|Publication number||US5869129 A|
|Application number||US 08/706,630|
|Publication date||Feb 9, 1999|
|Filing date||Sep 6, 1996|
|Priority date||Oct 18, 1993|
|Also published as||DE69428320D1, DE69428320T2, EP0649160A1, EP0649160B1, US6087769|
|Publication number||08706630, 706630, US 5869129 A, US 5869129A, US-A-5869129, US5869129 A, US5869129A|
|Inventors||Gerardus V. A. Aben, Jurgen P. A. Heymbeeck, Marcus J. Van Bommel, Angela C. L. Van de Poel|
|Original Assignee||U.S. Philips Corporation|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (5), Non-Patent Citations (2), Referenced by (13), Classifications (38), Legal Events (5)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This is a continuation of application Ser. No. 08/324,568, filed Oct. 18, 1994, now abandoned.
The invention relates to a method of manufacturing an antistatic coating which consists of more than one layer on a display screen and which comprises at least one antistatic layer.
The invention also relates to a display screen having an antistatic coating.
Antistatic coatings are used on display screens of display devices, in particular CRTs. Such coatings are sufficiently electroconductive to ensure that a high electrostatic voltage present on the outside surface of the display screen is removed within a few seconds. Thus, the user does not experience an unpleasant shock if he touches the screen. Besides, the attraction of atmospheric dust is reduced.
One of the layers of the coating is an antistatic layer comprising an electroconductive compound. Known coatings comprise, in addition to such antistatic layer, layers having, for example, an antireflective or antiglare effect or a layer which improves the scratch resistance. Usually these other layers are provided by spinning or spraying of a silica layer.
A method of the type mentioned in the opening paragraph is known from "Japan Display '92, pp. 289-292: "Anti-glare, Anti-reflection and antistatic (AGRAS) Coating for CRTs"", by H. Tohda et. al. In this document a method is described in which a display screen is provided with a conductive (antistatic) SnO layer by means of CVD (Chemical Vapour Deposition), whereafter a central and outermost SiO2 layer are provided by, respectively, spinning, spraying and a thermal treatment.
This method is very laborious and time consuming; the CVD process is carried out in a separate reaction space. After the SnO layer is provided the surface is treated by means of polishing and cleaning.
It is an object of the invention to provide a simple method of manufacturing multilayer antistatic coatings.
In accordance with the invention, the object of providing a simple method of manufacturing a multilayer antistatic coating is achieved in that a layer of conductive particles is provided on the display screen, whereafter a second layer of a compound is provided and this compound penetrates into the first layer, after which the compound is converted into an additional second layer by subjecting it to a treatment at an increased temperature.
The penetrating compound causes the layer to be sealed and to adhere to the surface of the display screen. It is no longer necessary to subject the first layer to further treatments, such as polishing and cleaning, to obtain a satisfactory adhesion between the first and the second layer. By virtue thereof, a substantial simplification of the method is possible. Preferably the layer of conductive particles is a porous layer. Penetration of the compound into the first layer is thereby promoted.
It should preferably also be possible to carry out the method at relatively low temperatures. The use of relatively low temperatures generally reduces the process time and the risk of damage as a result of thermal stresses.
To this end, an embodiment of the method in accordance with the invention is characterized in that an aqueous suspension of particles of antimony-doped tin oxide is provided on the display screen and subsequently dried thereby forming the antistatic layer, whereafter, preferably a second layer of an alcoholic or aqueous alkoxy silane or titane compound is provided on the antistatic layer, after which said alkoxy silane compound is converted into silicon dioxide or titanium dioxide by subjecting it to a treatment at an increased temperature.
This embodiment of the method in accordance with the invention enables a subsequent layer to be provided on the antistatic layer without previously curing the antistatic layer. The alkoxy silane compound can be converted into silicon dioxide at relatively low temperatures (up to 200° C.). By virtue thereof the method can be simplified.
The conversion into silicon dioxide takes place, for example, by means of a treatment of at least 30 minutes at a temperature in the range between 150° C. and 170° C. The alkoxy groups of the alkoxy silane compound are converted into hydroxy groups by acidified water, with the hydroxy groups reacting with each other and with hydroxy groups of the glass surface of the display screen. During drying and heating a firmly adhering network of silicon dioxide is formed by polycondensation. A similar conversion takes place for alkoxy titane compounds.
The use of aqueous suspensions for the antimony-doped tin oxide particles has the advantage that they are less harmful to the environment. Consequently, fewer measures or perhaps no measures at all have to taken to preclude environmental pollution, so that the method can be simplified. A further advantage is that the square resistance of the layer obtained is low, i.e. approximately 1-10 MΩ. This resistance value is much lower than the values obtained with conductive layers on the basis of ATO which are made in a different manner. A further advantage of aqueous suspensions is that the adhesion of the ATO particles to the display screen suffices to dispense with a temperature treatment after the layer has dried, so that the second layer can be directly provided, for example from an aqueous or alcoholic solution of an alkoxy silane or titane compound. As soon as the coating of ATO particles has dried, the layer of the alkoxy silane solution can be provided.
The aqueous suspension is preferably provided by means of spinning. The layer thickness of the first layer, which thickness determines, inter alia, the optical and electrical properties of the coating, can then be accurately controlled. The first layer may comprise further particles, e.g. to influence the optical properties of the first layer e.g. the transmissivity and/or the refractive index.
The second layer is preferably provided by spinning.
By spinning of the alkoxy silane or titane solution a homogeneous, smooth layer is formed. Optionally, a surface-active substance is added to the solution, for example in quantities of from 0.001 to 5 wt. %.
The terms "spinning" or "spin coating" generally refer to a method in which a layer is provided on a rotating member, in this case a display screen.
Preferably, both the first and the second layer are provided by spinning without interrupting the rotation of the display screen.
This has the advantage that the production of a two-layer coating can be carried out in one and the same spinning unit. The second layer can be provided without a change of position. The display screen continues to rotate, thereby precluding dust from settling on the display screen since the air flow produced above the display screen during spinning is maintained. This enables both a simplification of the method as well as an improvement of the quality of the coating.
The method in accordance with the invention can be used for applying a coating on a display screen of a display device. Within the framework of the invention it has been recognized that the preferred method can be used and, preferably, is used for applying coatings to a display screen which forms part of a cathode ray tube.
In the method disclosed in the above-mentioned article from Japan Display, a coating is applied to a display screen which constitutes a separate part, i.e. first a display screen is provided with a coating and it is not until the display screen has been provided with a coating that the cathode ray tube is assembled. This holds the risk that the coating is damaged during assembly of the cathode ray tube. This risk is avoided by providing the coating on a display screen which forms part of a cathode ray tube. The known method is not suited for this purpose.
The antistatic layer produced by means of the method in accordance with the invention comprises conductive, for example ATO (Antimony-doped Tin Oxide) particles, which ATO particles provide the antistatic properties of the layer.
Preferably, the conductive (ATO) particles used are very small, i.e. their dimensions are preferably below 50 nm. By virtue of these small dimensions no visible scattering of light occurs and the first layer formed is transparent. The particles are sufficiently electroconductive if the molar ratio Sb/Sn is smaller than 0.3.
The particle size is preferably below 30 nm. By virtue of the small dimensions of the ATO particles, Van der Waals' forces occur which cause the adhesion of the ATO particles to a glass substrate to be sufficient to provide the second layer without disturbing the first layer. The ATO particles are provided on the display screen from an aqueous, stable ATO suspension (hydrosol). In the suspension, the ATO particles are charge-stabilized instead of sterically stabilized. Such a suspension can suitably be used for the manufacture of very thin layers having a surface resistance of approximately 1-20 MΩ/square. The preparation of such an ATO suspension is described in U.S. Pat. No. 4,775,412. By virtue of the small particle size, the mechanical strength and adherence of the layer suffices to directly provide a second layer without an intermediate curing step.
The first layer is preferably supplemented with layers of silicon dioxide having an antireflective or antiglare effect, with the additional layers also increasing the scratch resistance. The second layer serves, inter alia, as an adhesive for the first layer with ATO particles. The alkoxy silane compound (for example TEOS) penetrates into the first layer and adheres to the underlying surface. Preferably, the second layer and the first layer together form a 2-layer antireflective layer. Antireflective layers are used on display screens to reduce reflection losses of traversing light and to suppress disturbing reflections in images (specular reflection). Antiglare layers are used to reduce the specular reflection of ambient light.
An alkoxy silane compound which can suitably be used in the method in accordance with the invention is tetraethyl orthosilicate (TEOS). It is alternatively possible to use other known alkoxy silane compounds of the type Si(OR)4 and oligomers thereof, wherein R is an alkyl group, preferably a C1 -C5 alkyl group. For the solvent use is made of, for example, methanol or ethanol.
The invention also relates to a display device comprising a display screen having an antistatic, antireflective coating. A display device comprising a display window having an antistatic coating which consists of more than one layer and which comprises at least one antistatic layer is characterized according to the invention in that the antistatic layer is directly adjacent to the display window and comprises conductive particles having a diameter below 50 nm which are embedded in silicon dioxide or titanium dioxide, which antistatic layer is covered by a second smooth layer which contains silicon dioxide or titanium dioxide, the assembly of the first and the second layer having an antireflective effect for visible light.
The refractive index of the antistatic layer comprising conductive (ATO) particles generally differs from, and is higher than, the refractive index of the additional silicon dioxide layer (for TiO2 the refractive index of the conductive layer could be lower than the TiO2 layer). The respective layer thicknesses of a two-layer coating are preferably selected such that destructive interference occurs at a central wavelength λ in the visible range, for example approximately 550 nm. For this wavelength, and for wavelengths in a range around said wavelength, the stack of layers has an antireflective effect. It is known to those skilled in the art that the optical thicknesses n.t (wherein n is the refractive index and t is the layer thickness) of the layers must be equal to λ/4, wherein λ is the central wavelength. Such an additional layer of silicon or titanium dioxide can be manufactured by providing an alcoholic solution of an alkoxy silane or titane compound, followed by a treatment at an increased temperature, thereby forming a layer of silicon or titanium dioxide. If the additional layer is provided by spinning, the layer thickness obtained depends, inter alia, on the number of revolutions and the viscosity of the solution. Preferably, the particle size is smaller than 50 nm. The first layer may comprise other particles influencing e.g. the optical properties of the first layer, e.g. transmissivity and/or refractive index. The anti-reflective effect could be obtained in cooperation with a third or fourth etc layer.
Preferably, a third layer of silicon dioxide having an antiglare effect is provided. This layer is provided on the first additional layer by spraying or atomizing an alcoholic solution of an alkoxy silane compound, followed by a treatment at an increased temperature, thereby forming a layer of silicon dioxide. The layer obtained is scratch resistant and has antiglare properties due to the surface texture obtained by spraying. The antiglare effect is substantially independent of the wavelength of the light. A mat surface texture is obtained by spraying or atomizing the alkoxy silane solution, so that the layer exhibits an antiglare effect. By virtue thereof, ambient light is diffusely reflected.
Further advantages of the additional layers of silicon dioxide are the reduced sensitivity to fingerprints and the higher hardness and scratch resistance.
If desired, one of the additional layers may be provided with a pigment or dye to selectively influence the light transmission. Such pigments or dyes are selected in such a manner that the light emitted by the phosphors of a cathode ray tube is selectively transmitted, whereas, for example, the ambient light reflecting at the rear side of the display screen is absorbed. Examples of pigments are transition metal oxides, such as iron oxide and chromium oxide. An example of a suitable dye is Rhodamine B.
In an embodiment of the invention, latex particles of polypyrrole are added to the aqueous solution of (ATO) particles. The polypyrrole particles provide the light-absorbing properties of the first layer. After drying, the first layer then comprises polypyrrole-latex particles.
For the polypyrrole compound use can be made of polypyrrole, N-substituted polypyrrole and β-substituted polypyrrole. For the substituents use can be made of: alkyl groups having, for example, up to 5 carbon atoms, aryl groups, alkoxy groups, nitro groups and halogen atoms. Such materials and the preparation of latex particles, inter alia, for use as an antistatic coating, are described in U.S. Pat. No. 4,959,162. Also this American Patent describes a centrifuging step and a re-dispersion step to purify the latex thus prepared. Preferably, the latex particles consist of unsubstituted polypyrrole.
Owing to the optical properties, uniformity and homogeneity of the layer, it is desirable for the latex particles to have uniform dimensions. The latex particles are spherical and preferably have an average diameter in the range between 50 and 150 nm, preferably around 60 nm. In such an embodiment, antistatic and light-absorbing properties are combined in a single layer. As a result of the method in accordance with the above embodiment of the invention, the coating comprises a homogeneous mixture of both types of particles. The layer thickness of the coating lies in the range between 50 and 200 nm. The colour of the coating is neutral grey, i.e. the transmission is independent of the wavelength. Dependent upon the layer thickness and the concentration of polypyrrole in the layer, the transmission can be adjusted, for example, between 90% and 30%, while preserving the required antistatic effect. A sufficient antistatic effect of the coating is attained if the surface resistance of the layer ranges below 1010 Ω/square, preferably between 104 and 1010 Ω/square.
As described above, the combination of the coating and the additional layer of silicon dioxide exhibit an antireflective effect if the optical layer thicknesses of these layers are equal to approximately λ/4. The desired layer thicknesses can easily be experimentally determined. Important process parameters are the number of revolutions during spinning, the temperature and the viscosity of the solution.
The invention will be explained in greater detail by means of exemplary embodiments and with reference to a drawing, in which
FIG. 1 shows a display device,
FIG. 2 is a sectional, diagrammatic view of a display window of a display device,
FIGS. 3a, 3b and 3c show an embodiment of the method in accordance with the invention,
FIG. 4 shows the transmission T (in %) as a function of the wavelength λ (in nm) of a coating in accordance with the invention,
FIGS. 5a and 5b show the relative reflection R (in %) as a function of the wavelength λ (in nm) of a coating consisting of ATO (and polypyrrole) particles carrying an additional layer of silicon dioxide and a second additional antiglare layer of silicon dioxide.
FIG. 1 is a diagrammatic cut-away view of a cathode ray tube 1 having a glass envelope 2 comprising a display screen 3, a cone 4 and a neck 5. In the neck there is provided an electron gun 6 for generating an electron beam. This electron beam is focused on a phosphor layer on the inside 7 of the display screen 3. In operation, the electron beam is deflected across the display screen 3 in two mutually perpendicular directions by means of a deflection coil system (not shown). The display screen 3 is provided on the outside with an antistatic coating 8 in accordance with the invention.
FIG. 2 is a diagrammatic, sectional view of a display screen in accordance with the invention. An antistatic coating 8 is provided on the display screen 3. This antistatic coating 8 comprises a first layer 9 (AS), a second layer 10 and a third layer 11. The first layer 9 comprises conductive particles 12, in this case antimony-doped tin oxide particles, embedded in a second compound, in this example silicon dioxide. The second layer is made of the second-mentioned compound, in this example silicon dioxide. The first layer and the second layer together form an antireflection filter (AR). To this end, the thickness of both layers 9 and 10 is approximately λ/4, wherein λ is situated in the visible range, for example between 500 and 600 nm. The first layer may be provided with polypyrrole latex particles, enabling the transmission properties of the first layer to be determined. The third layer 11 (AG) provides an antiglare effect and consists, for example, of sprayed-on silicon dioxide.
FIGS. 3a up to 3c illustrate a method in accordance with the invention.
A porous layer 31 is provided on the display screen 3. This is preferably carried out, for example, by providing an aqueous solution of conductive (ATO) particles on the display screen and drying said particles. A second layer 32 of a compound is applied to the layer 31 and the compound penetrates into the first layer. After provision of the second layer, a thermal treatment is carried out. This treatment results in the formation of a silicon dioxide layer. Subsequently, a third layer is applied to obtain an antiglare effect, for example, by spraying of a silicon-dioxide antiglare layer.
Below a description will be given of a number of embodiments of the invention.
An aqueous ATO suspension is prepared as described, for example, in U.S. Pat. No. 4,775,412. According to this document, SnCl2 and SbCl3 are dissolved in diluted hydrochloric acid, whereafter ammonium bicarbonate is added to the solution. In an autoclave a hydrosol of antimony-doped tin oxide is formed by hydrothermal conversion. The ATO particles are smaller than 30 nm. In a typical example, the molar ratio Sb/Sn is 0.3. The aqueous ATO suspension amounts to 5 wt. %. This ATO suspension is provided on the display screen and dried.
A solution of an alkoxy silane compound has been or is manufactured in accordance with Table 1.
TABLE 1______________________________________preparation of TEOS-solution (250 ml)Composition and preparation: *mix (grams):______________________________________ TEOS 11.25 ethanol 5.63 0.175 M HCL 5.63______________________________________ *hydrolysing for 30 min *adding ethanol/butanol (1:1) to obtain 250 ml
On the first layer, which is obtained as described hereinabove (a dried layer comprising conductive particles (for example ATO)), a layer of the TEOS solution prepared in accordance with Table 1 is provided, for example, by spinning. The layer is maintained at a temperature of 160° C. for approximately 90 minutes, thereby forming a firmly adhering, smooth layer of silicon dioxide. This additional layer of silicon dioxide has a layer thickness of, for example, 135 nm and a refractive index of 1.44. This layer, in combination with the antistatic layer which comprises ATO particles and into which silicon dioxide has penetrated and which has a refractive index of 1.62 and a layer thickness of 60 nm, exhibits an antireflective effect. It is noted that the sequence in which the layers are applied is important. If the silicon dioxide layer were to be provided before the layer containing the ATO particles, this would adversely affect the adhesion of the coating and the refractive index of the layer comprising ATO particles would be different, namely approximately 1.4, and the layer would contain no or perhaps hardly any silicon oxide. Furthermore, an anti-reflective effect would be virtually non-existant (the indices of refraction of both layers would hardly differ).
Consequently, the optical and mechanical properties of the assembly of the first and the second layer depend on the sequence in which the layers are provided. Preferably, the antistatic layer and the second layer are provided by spinning. Preferably, this is carried out in one and the same spinning unit without interrupting the spinning process of the display screen. This results in a simplification of the method and precludes dust from settling on the display screen.
Subsequently, if desired, use is made of a TEOS solution and a similar temperature treatment to provide a second additional layer of silicon dioxide by spinning. This layer has a mat surface texture having an antiglare effect. Consequently, the coating obtained is less sensitive to fingerprints. In addition, the reflection is less dependent on the wavelength because the incident light is diffusely scattered. The above method can be used to provide a coating (two-layer or multilayer) on a loose display screen, i.e. a display screen which does not (yet) form part of a cathode ray tube. Preferably, however, the method is used to provide a coating on a display screen which forms part of a cathode ray tube. The risk that the coating becomes damaged is smaller then.
In this exemplary embodiment a description is given of a method and a display device in which the first layer also influences the transmission of visible light by the incorporation of polypyrrole latex particles in the first layer.
Polypyrrole latex particles are prepared by vigorously stirring a mixture of 0.938 g pyrrole, 8.65 g FeCl3.6H2 O and 1 g polyvinyl alcohol (steric stabilizer) in 100 ml water for at least 10 hours until a clear solution is obtained. The formation of polypyrrole particles can be recognized by the blackening of the mixture. The suspension obtained is dialysed with demineralised water to remove Fe2+ ions and Cl- ions. After dialysis, several millilitres of ethanol, butanol and ethyl acetate are added to the suspension. Finally, the suspension is passed through a 5 μm and a 0.2 m filter of polyamide. Electron microscopy shows that the latex particles have a regular, spherical shape and that they are monodisperse with an average particle size of 80 nm.
The preparation of an ATO suspension is carried out in the way described in example 1.
Equal quantities of both suspensions are subsequently mixed, thereby forming a stable suspension of ATO and polypyrrole particles. This suspension is subsequently provided on a display screen by means of spin coating. After drying, a homogeneous, neutral grey coating having a thickness of 60 nm and a resistance of 1 MΩ/square is obtained. This is amply sufficient for the desired antistatic effect (a surface resistance in the range between 104 and 1010 Ω is desirable) and makes it possible to bring the light transmission properties to the desired value by changing the layer thickness and the concentration of the polypyrrole, while preserving the necessary antistatic effect. The transmission T (in %) as a function of the wavelength λ (in rim) of the coating obtained is shown in FIG. 4. The resistance value of the coating in accordance with the invention is much lower than the values of layers of silicon dioxide in which ATO particles or polypyrrole particles with a steric stabilizer are dispersed. Such layers have a resistance of approximately 100 MΩ. A solution of an alkoxy silane compound is prepared having the following composition: 0.9 mol tetraethyl orthosilicate (TEOS), 3.6 mol water, 5.10-4 mol nitric acid, which is made up to 1 litre by adding ethanol.
The first layer obtained in accordance with exemplary embodiment 2 is provided with a layer of TEOS solution by spinning. The layer is maintained at a temperature of 160° C. for 30 minutes, thereby forming a firmly adhering, smooth layer of silicon dioxide. This additional layer of silicon dioxide has a layer thickness of 135 nm and a refractive index of 1.44. This layer, in combination with the coating which comprises ATO and polypyrrole particles and which has a refractive index of 1.62 and a layer thickness of 60 nm, has an antireflective effect. It is possible to fine-tune the anti-reflective effect by slightly altering the layer thicknesses, for instance making the thickness of the first layer approximately 100 nm and the thickness of the second layer approximately 80 nm.
Subsequently, the same TEOS solution is used and a similar temperature treatment is carried out to provide a second additional layer of silicon dioxide by spraying. This layer has a mat surface texture having an antiglare effect. As a result, the coating obtained is less sensitive to fingerprints. In addition, the reflection is less dependent on the wavelength because the incident light is diffusely scattered.
FIG. 5a represents the relative reflection R (in %) as a function of the wavelength λ (in nm) of a coating consisting of the above-described layer of ATO particles (example 1) on which the additional layer of silicon dioxide and an antiglare layer (curve A) are provided. In the measuring process, uncoated display-screen glass is used as the reference material.
FIG. 5b represents the relative reflection R (in %) as a function of the wavelength λ (in nm) of a coating consisting of the above-described layer of ATO and polypyrrole particles (example 2) on which the additional layer of silicon dioxide (curve A) is provided. In the measuring process, uncoated displayscreen glass is used as the reference material. Curve B shows the effect of the additional antiglare layer. The antireflective effect of the coating has become less dependent on the wavelength.
The scratch resistance of the outermost layer is tested by means of a conical diamond which is moved over the surface at a force of 50 g and which does not form scratches which are visible to the naked eye.
The hardness is tested by means of a pencil-hardness test in which pencils having a different hardness exert a force of 7.5N on the surface over which they are moved at an angle of 45° and a velocity of 0.05 m/s. In accordance with this test, the inventive layer has a degree of hardness of from 3 H to 4 H.
By means of the above embodiments of the invention, effective antistatic coatings and, if desired, light-absorbing coatings are manufactured and provided on a display screen of a cathode ray tube in a simple manner, with the coatings enabling the light-transmission properties to be adjusted, whether or not as a function of the wavelength.
It will be clear that within the framework of the invention many other embodiments are possible. For instance an exemplary embodiment 3 in which an ATO-layer is covered with a TiO2 layer is described below.
An ATO suspension as described in exemplary embodiment 1 above is applied to a display screen and dried (dried means within the concept of the invention also left to dry). A solution of an alkoxy titane compound has been or is manufactured in accordance with Table 2.
TABLE 2______________________________________preparation of TEOTi-solution (250 ml)Composition and preparation:*mix (grams, ml)______________________________________TEOTi 5,775 grethanol 123 mlbutanol 120 mlwater (0.5 M HCl) 1,83 gr______________________________________ *stir for several hours
On the first layer of ATO particles a second layer of the TEOTi solution according to table 2 is applied, for instance by spinning. The double layer is subsequently held for approximately 90 minutes at a temperature of 160° C. The resulting coating comprises a second layer of TiO2 having an refractive index of approximately 2.0 on top of a layer comprising ATO-particles in a TiO2 matrix due to the fact that the titane compound is penetrated in the layer with ATO particles. The bottom layer has a refractive index of approximately 1.8 to 1.9. The bottom layer can have for instance a thickness of 60 nm whereas the second layer has a thickness of for instance 200 nm. On top of the TiO2 layer a SiO2 layer can be provided for instance by spinning a layer of a silane compound on the TiO2 layer.
It is also possible that the first layer may comprise further particles, e.g. to influence the optical properties of said first layer e.g. the transmissivity and/or the refractive index. An example has been given above in which the first layer comprises latex particles which influence the transmissivity of the first layer and therewith of the coating. It is also possible that the first layer comprises, besides the conductive particles, particles influencing other properties of the first layer, such as for instance the refractive index. A fourth exemplary embodiment is given below in which said first layer comprises particles influencing the refractive index of the first layer. By influencing the refractive index a fine-tuning of the optical properties and more in particular of the reflective properties of the coating can be achieved.
By mixing the conductive particles with e.g. anorganic colloidal oxides, such as SiO2 or Al3 O2 it is possible to influence the refractive index of the first layer. Preferably the oxide particles are smaller than 100 nm.
For example, to 100 grams of an ATO-solution (12% by weight), 7 grams of a colloidal SiO2 solution (40 weight % of SiO2) is added. This solution is diluted 1:4 with an alcoholic solution and applied to a screen by means of spinning. When the layer has dried up, a TEOTi solution (see e.g. exemplary embodiment 3) is by means of spinning applied to the screen. When the second layer has dried up, a third layer of a TEOS solution (see e.g. exemplary embodiment) is by means of spinning applied to the screen. Thereafter the three-layer coating is subjected to a treatment at a raised temperature to harden the coating. An exemplary coating in which the first layer (comprising ATO-particles and SiO2 particles) has a thickness of 70 nm and a refractive index of 1.75, the second layer (TiO2) has a thickness of 102 nm and a refractive index of 1.95 and the third layer SiO2 has a thickness of 90 nm and a refractive index of 1.44 has excellent anti-reflective properties. In the visible range the reflectivity is strongly reduced and between approximately 400 and 600 nm, the reflectivity is reduced to less than 10% of the reflectivity without a coating.
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|U.S. Classification||427/64, 427/68, 427/407.2, 427/419.3, 427/380, 427/126.3, 427/162, 427/385.5, 427/165, 427/389.7, 427/108, 427/226, 427/419.2, 427/126.2|
|International Classification||H01J9/20, H04N5/64, C03C17/34, H05F1/02, H01J29/86, C03C17/00, H01J29/89|
|Cooperative Classification||H05F1/02, C03C2217/47, C03C2217/45, C03C17/007, C03C17/3417, H01J29/896, C03C2217/445, C03C17/3411, H01J29/868, C03C2217/42, C03C2217/476|
|European Classification||C03C17/34D2, H01J29/86H2, H05F1/02, H01J29/89F, C03C17/00D2, C03C17/34D|
|Jul 24, 2002||FPAY||Fee payment|
Year of fee payment: 4
|Jul 27, 2006||FPAY||Fee payment|
Year of fee payment: 8
|Sep 13, 2010||REMI||Maintenance fee reminder mailed|
|Feb 9, 2011||LAPS||Lapse for failure to pay maintenance fees|
|Mar 29, 2011||FP||Expired due to failure to pay maintenance fee|
Effective date: 20110209


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Compensation for discharge of worn mold material as well as mold material output losses.
Due to the mechanical, thermal, and chemical loads certain wear products occur in the mold material cycle. Examples include quartz sandfines, inactive clay contents, decomposition products of coal dust or core binders, oolitized quartz grains.
The flow of coresand particles can also introduce harmful wear products. They all accumulate in the mold material system. By means of controlled feeding of new sand and discharge of the same amount of worn mold material (s. Mold material balance) it is possible to ensure that specified limits are not exceeded to thus maintain a specific level properties.
The adjustment of the sediment content is of particular importance. Moreover, new sand must be added to compensate for the mold material output losses.
Mold material management
Mold material recovery
Mold material control


Here we report on the second-order nonlinear optical properties of chiral chromophore-functionalized polybinaphtalenes. These materials are designed from chiral binaphtalene units, connected with rigid groups. This molecular architecture gives rise to a rigid, rod like (helical) structure. Chromophores which moderate to good hyperpolarizabilities were incorporated to induce a strong second-order nonlinear optical response. The polymers are soluble in common organic solvents and spincoated films of high optical quality can be readily obtained. The spincoated films were subsequently poled by an external electric field and analyzed by second-harmonic generation. The films showed excellent second-order nonlinearities, as high as 100 pm/V. Maybe even more important was the observation that the nonlinearity of these materials increases linearly with increasing chromophore content, in contrast to what has been observed for traditional side-chain polymers. This is due to the rigid character of the polymer backbone which effectively prevents detrimental chromophore aggregation at high chromophore concentrations. This property opens up perspectives to achieve materials with very high second-order nonlinearities. Another interesting observation was the fact that chiral contributions to the nonlinear optical response can be observed, which may further increase the nonlinearity.


|Brand Name|| |
COLLAGEN PEPTIDE TYPE (1) SODIUM HYALURONATE,CHONDROITIN SULFATE SODIUM AND VITAMIN C
|Pack Type|| |
|Pack Size|| |
10 X 1 X10
Tendomor contains nutritional supplement which is Collagen Peptide Type-1, Sodium Hyaluronate, Chondroitin Sulfate & Vitamin C which are used in various bone and joint disorders as it acts as building blocks for tissues like skin, bones, cartilage, teeth, tendons, etc. the tablets are very useful in the treatment of joint and muscles as it provides the strength, flexibility, and recovery the injury of issue tear.
Collagen peptide type I constitutes 30% of body protein and is known as the main building protein in bone and cartilage, skin, and other connective tissues. The tablets help to improve the cartilage damage by supporting the repairing and offering fluids for cushion and elasticity.
Sodium Hyaluronate with Chondroitin Sulphate helps in decreasing the inflammation (swelling and redness) associated with Osteoarthritis problems whereas Vitamin C is a water-soluble vitamin with antioxidant activity required by the body to make collagen the most abundant protein in the body. The table also helps in the problems like arthritic pain, stiffness, joint pain, and osteoarthritis.
Collagen Peptide Type-1, Sodium Hyaluronate, Chondroitin Sulfate & Vitamin C Tablets Beneficial For
These tablets are used in the treatment of Arthralgia (Joint Pain). All the active ingredients are proteoglycan synthesis stimulators which help in the building of cartilage which leads to the process of joint repairing. Cartilage is a non-vascular type of soft tissue that cushions the joints. Along with it, this medication also lowers pain, swelling, and inflammation.
Collagen Peptide Type-1, Sodium Hyaluronate, Chondroitin Sulfate & Vitamin C Tablets may cause some common side effects which aren’t big in nature and tend to go away with time. A doctor’s consultation should be taken if they don’t go away after a while as they can worsen over the period of time.
Directions For Use
This medicine should be used after having a meal as it will help in its proper digestion. The dosage should be continued as per the advice of the doctor so that none of the doses gets skipped and it should be tried to take them at the same time every day.
These tablets should be taken as per the guidance of the concerned doctor and taking an overdose isn’t advised as it can lead to some chronic problems which can cause further problems. The individual should consult a doctor before using these tablets if suffering from any liver, kidney, or another disease.
Aden Healthcare is one of the top leading Pharma companies that are doing very well to offer a wide range of pharma drugs to all the linked individuals. A good number of promotional tools are being offered by us which makes us the top Collagen Peptide Type-1, Sodium Hyaluronate, Chondroitin Sulfate & Vitamin C Tablets manufacturer and supplier in India. The company is also recognized as one of the best firms who are offering Collagen Peptide Type-1, Sodium Hyaluronate, Chondroitin Sulfate & Vitamin C Tablets PCD Pharma Franchise in various parts of the nation. The manufacturing unit of the firm is featured by a good number of machines that are capable of processing bulk orders whenever required.


This low pH cleanser mildly cleanses skin and removes impurities with gentle foam action. The ingredients soothe and calm irritated skin at the same time.
This product is currently sold out.
- Centella asiatica extracts soothe irritated skin and moisturizes.
- Madecassoside creates a barrier to protect skin and keep moisture in.
About the brand: COSRX is a South Korean beauty brand that has been providing clean beauty to their customers since 2015. They focus on using transparent ingredients, cruelty free practices and creating hypoallergenic products.
How to Use
Can be used after an oil based cleanser to double cleanse. Lather the product and massage onto face. Rinse with lukewarm water and follow up with the rest of skincare routine.
Caution: For external use only. Always patch test. Discontinue use if you feel any discomfort. Follow additional instructions on box. Individual results may vary. This product contains citric acid: an alpha hydroxy acid that may increase your skin's sensitivity to the sun and particularly the possibility of sunburn. Please limit sun exposure while using this product and for a week afterwards.
Water, sodium cocoyl isethionate, glycerin, glyceryl stearate, stearyl alcohol, coco-betaine, sodium methyl cocoyl taurate, sodium chloride, coco-glucoside, caprylyl glycol, glyceryl caprylate, citric acid, eucalyptus globulus leaf oil, disodium edta, ocimum basilicum (basil) oil, 1,2-hexanediol, quillaja saponaria bark extract, propanediol, centella asiatica extract, centella asiatica leaf extract, centella asiatica root extract, saccharomyces ferment, ethylhexylglycerin, asiatic acid, asiaticoside, madecassic acid, madecassoside, pinus pinaster bark extract.*May contain additional ingredients.


Projects per year
Towards the synthesis of the novel natural product Agariblazeispirol C, (5aR*,11bR*)-9-methoxy-3,8,11b-trimethyl-5,6,7,11b-tetrahydro-1H-pentaleno[1,6a-a]naphthalen-4(2H)-one, C20H24O2, has been prepared at a key stage of the preparative programme. The structure shows the desired stereochemical outcome of the central cyclization protocol, viz. a syn-relationship between the aliphatic methyl group on the 11b-position and the methylene group on the 5a-position [C-C-C-C = -34.57 (18)degrees].
|Number of pages||2|
|Journal||Acta Crystallographica Section C: Crystal Structure Communications|
|Publication status||Published - Sep 2010|
- alpha-carbonyl radicals
- formal total-synthesis
FingerprintDive into the research topics of 'A tetrahydropentaleno[1,6a-a]naphthalen-4(2H)-one of defined relative stereochemistry for use towards Agariblazeispirol C'. Together they form a unique fingerprint.
- 1 Finished


I have long been a bit creeped out when i enter a room full of burning candles. I love the ambience, but paraffin, folks, is a hydrocarbon just like diesel, and hydrocarbon exhaust is hydrocarbon exhaust. I wouldn’t feel good about hanging out in a room filled with burning diesel lamps, no matter how mellow the ambience.
Fortunately there are alternatives: beeswax and soy wax, for two, that avoid some of the downsides of paraffin and also don’t feed the oil industry.
This from a pamphlet put out by Avalon Sunset Candles, makers of beeswax candles:
Many commercial candles are made from paraffin, the greyish-black sludge that oozes from the backside of the petroleum refineries. It’s bleached, textured with a carcinogenic product called acrolyn, chemically coloured and artificially scented.
Did you know? — Paraffin candles create black smoke and soot that coats your home and even your lungs. Fumes from a paraffin candle are like breathing diesel exhaust fumes.
What about the wick? — Health Canada is urging the Canadian candle industry to stop manufacturing and importing candles with lead and zinc core wicks. They are hazardous to human health — even in small amounts. Some candlemakers use lead and zinc cores to make the wicks rigid.
- Beeswax candles produce negative ions that attract positive ions. But positive ions aren’t so positive. They’re the pollutants such as dust, odours, toxins, pollen, mold, bacteria and viruses that are floating in the air. Beeswax neutralizes the pollutants and they simply fall to the ground. The dustier your home, the more “black debris” you’ll find deposited in the wax around the wick.
- Beeswax is a safe, valuable fuel — one of the purest known. It burns slower than paraffin, so it’s cheaper to use. Beeswax burns with a golden halo and is significantly hotter than paraffin. Please note: candles listing beeswax as an ingredient may contain as little as 30% beeswax. If it doesn’t state on the label “100% beeswax,” it probably isn’t.
And here’s a page of info on candles made of soy.
You have to do a bit of searching (in nonmainstream stores, of course) but i’ve found both soy and beeswax candles in Ucluelet, so they must be available pretty much everywhere. Be mellow, be healthy!


Two individuals have died in Ontario, Canada after drinking alcohol based hand sanitizer. According to CBC News, the hand sanitizer contained methanol which is lethal if ingested.
According to the news article:
“Hand sanitizers typically contain ethyl alcohol, not methanol. Ontario’s Centre of Forensic Sciences performed tests on bottles of Bodico-brand hand sanitizer and confirmed that they contained methanol, although the ingredient label did not list it. They are working with the company to test additional products and to issue a recall.”
Because the hand sanitizer was not properly labeled according to the article, there has been a recall of the product.
If you are in Canada and need more information about this brand of alcohol based hand sanitizer and its recall, please see the info below.
Health Canada is working with the company to implement a recall of these products.
Report health or safety concerns
Call toll-free at 1-866-234-2345
Visit MedEffect Canada’s web page on Adverse Reaction Reporting for information on how to report online, by mail or by fax.
** Please note that SafeHands Alcohol Free Hand sanitizer does not contain ethanol or methanol or any of the ingredients mentioned in the above article.
Also note: We are complying with FTC and FDA regulations and not mentioning any brand names of alcohol based hand sanitizers which are FDA approved as safe and effective. There is no category defining alcohol brand of hand sanitizer.


Taking too much folic acids?
- 07-16-2011, 10:06 PM #9Registered User
- Join Date
- May 2011
- hong kong
Noted that Materna formula in hong kong and in Canada the formulation different.
Also 1mg is 1000mcg
As I said on my first post. Different country got different formulation and ur not over dozing
- 07-17-2011, 06:53 AM #10Registered User
- Join Date
- Jan 2009
- Hong Kong
folic acid 1000mcg?
Yes, agree that folic acid is water soluble, so you will eliminate what isn't used (it is not like fat soluble vitamins which are stored in the body, accumulative and therefore used with caution in pregnancy). However, most B vitamins (folic acid incuded) have synergistic relationsips with other vitamins meaning taking too much or something can put the balance out of another nutrient. Having said that, there are studies sugesting that 1000mcg is now the preferred dose of folic acid and is associated with the prevention of miscarriage and neural tube defects.
- By Zoska in forum Hong Kong Pregnancy ForumReplies: 4Last Post: 05-07-2011, 06:04 PM
- By dorothy_melody in forum Hong Kong Pregnancy ForumReplies: 9Last Post: 07-27-2008, 08:37 PM
- By helywong in forum PreconceptionReplies: 12Last Post: 06-09-2008, 01:07 PM
- By putput in forum Hong Kong Pregnancy ForumReplies: 8Last Post: 08-22-2007, 02:35 PM
- By Spanjo in forum Hong Kong Pregnancy ForumReplies: 2Last Post: 08-07-2003, 01:57 PM


A Perfect Reaction: You are about to write a paper. You have fully characterized your compound, so you do not need to rerun any experiments before submission. Also, you have written an exact description of your experiment in your notebook, which another chemist can reproduce without further consultation, on the first try.
A Nightmare Scenario: It's time to write your thesis. You find that characterization data is missing, and need to repeat some experiments you ran earlier. Your notebook is not very detailed, and you have trouble reproducing the results, and have to work out the experimental conditions and a purification protocol all over again.
Designate a notebook for literature search information. Record the date, the search parameters, what references were found, and which ones you looked up.
Develop a filing system for literature/ experimental procedures that is consistent and allows you to find things easily. Everyone has different methods that make sense to them.
Ask your advisor how to organize your notebook entries- each group has different standards.
Leave space for an index at the beginning of the notebook, and record each experiment and the results by page number.
Write a complete experimental procedure.
Write in your notebook the complete reference for the literature source you are using.
Record the date you start an experiment.
Do NOT write down a complete equation (Reactants --> products) until after you have run the experiment and identified the products. Instead, start with "Reactants --> <blank>". Sometimes you don't get what you expected, and sometimes the experiment doesn't work. It is nice to be able to see what happened from the equation in the notebook.This way you can record what actually happened during the experiment.
Calculate and write down the theoretical yield of the process.
Write the concentration of the reagents in solvent (see Rule of thumb).
If you've run the experiment before, reference the earlier page for procedure. You should still record times, yield, and anything you do differently from the referenced page.
Write down the time (o'clock) you start the reaction, times of temperature changes, and the time you quench it. Sometimes recording TLC data at an intermediate time is also informative.
Record observations like color, clarity of solution, appearance of precipitate, etc.
Include all TLC plate data, including type of stain, solvent system, and any colors or UV activity. Drawing a picture of the plate or even Xeroxing it is a good idea.
Describe the workup and purification method in detail, noting any problems that occur along the way. This is very helpful when repeating the experiment.
Calculate and record yield, and describe the appearance of the isolated product.
If you have ideas for changes to improve the process, WRITE the suggestions in your notebook. These notes will be helpful for reference, the next time you run the experiment.
Develop a consistent labeling system for experiments that produce more than one product.
Starting with the most nonpolar compound, label the first product (notebook #)-A, the second (notebook #)-B, etc.
Develop a method for organizing your spectra.
Write your notebook page number on your spectrum.
Write the structure of the suspected product on the spectrum, as well as isomer ratios, if applicable.
Keep routine spectra in notebook number sequence. For example, I-10 (crude), I-10A, I-10B, I-11, etc.
Keep all good-quality spectra (1H and 13C NMR, IR, etc.) for important compounds together in their own files.
Develop a method for organizing storage of your synthetic samples
Keep everything that is an unsolved mystery.
Keep small samples of synthetic intermediates for TLC comparison.
Keep samples well sealed, well-labeled and in the freezer.
Keep any sample intermediate or reagent you made that is greater than or equal to 0.5 grams - someone might find it useful!


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Exclusive Creatine Blend For Amazing Results!
Creatine is one of the most effective supplements you can buy. Its benefits include:
• Increased Muscle Growth and Strength
• More Training Energy
• Improved Recovery
• Improved Pumps
Leave it to Top Secret to take the effectiveness of creatine and improve it!
Introducing Creavar: The Evolution of Creatine
Most everybody already knows about the benefits of creatine, but there may be more than you’re aware of. Creatine is made from the combination of three amino acids: arginine, glycine, and methionine. Its primary function in the body is as part of the ATP energy system. When ATP energy is used, it becomes ADP; creatine phosphate converts ADP back into ATP to be re-used as energy. This energy re-cycling process has numerous benefits, such as improved contraction time – this means you can train harder before you hit failure. This particular energy system is capable of generating about 4-30 seconds of energy. Research has indicated that supplementing with creatine may improve anaerobic ATP synthesis for fast twitch type II muscle fibers. As well, research conducted by the University of Maryland, among many other studies, has shown that creatine increases strength, promotes muscle growth and improves recovery time.
We took the basics of what creatine does for the body and enhanced it by surrounding it with several muscle strength, support, and growth facilitators.
We’re using a Creatine Tri-Blend in Craevar. We start with Creapure, a pure, superior quality creatine monohydrate that’s manufactured by AlzChem AG and has a well-deserved reputation for quality and purity, in large part due to the precise selection of raw materials and the use of an advanced, patented system for synthesizing creatine.
Secondly we use Creatine MagnaPower. This combination of magnesium and creatine has been research shown to have substantial positive benefits. It’s interesting to note that each compound has some similar functions and actually alternate together in numerous specific functions. This realization led Albion Advanced Nutrition, the manufacturer of Creatine MagnaPower, to combine magnesium and creatine, a ground-breaking idea that makes sense. Creatine MagnaPower is so revolutionary it’s patented.
This combination of magnesium and creatine provides the benefits:
• Increased ATP Production for Improved Workout Performance
• Enhanced Pump
• Improved Protein Synthesis
The final component of our Creatine Tri-Blend is Creatine AAB 2:1 - another patented version of creatine monohydrate, this time combined with alpha amino n-butyrate, which is a metabolite of leucine. This addition enhances muscle protein synthesis and reduces muscle breakdown. To see how creatine benefits in this case, we need take a look at branched-chain amino acids, primarily leucine. Leucine has been the target of quite a bit of extensive research that shows its anti-catabolic and protein synthesis enhancing benefits – in fact this research has caused quite a bit of excitement. In other words, leucine is directly involved in muscle growth.
Research conducted by Layman, indicates that after a workout, for muscle protein synthesis to take place, intake of protein or a branched-chain amino acid mixture was required. During a workout, the body requires more leucine to support an anabolic environment. It’s at this point that alpha amino butyrate enters the picture. AAB is very close to leucine, for this reason it’s been indicated that AAB can impact protein synthesis in the same manner if levels of leucine are low.
This version of Creatine AAB 2:1 provides the following benefits:
• Enhanced Protein Synthesis
• Improved Workout Endurance
Many products would stop right there, after all, we already have three effective creatines, what else is needed? A team of supporting ingredients:
1. Red Beet Extract
The primary benefit of Red beet root is that it’s high in nitrates (NO3); research has suggested NO3 can improve training performance. Research conducted in 2009 by the University of Exeter and published in the Journal of Applied Physiology, determined that NO3 can increase cycling endurance. Nitrates are important to athletes due to the fact that they can rapidly bring oxygen to working muscles. In another study, conducted in 2009 by Bailey et al. it was determined that supplementing with beet root can decrease the oxygen cost of exercise, this means that beet root can help extend intense training sessions.
Its been suggested that enhanced workout performance is because of an increase in levels of nitric oxide by a different means than the typical l-arginine nitric oxide pathway. This is referred to as the nitrate nitrite nitric oxide pathway, and it functions primarily in response to decreased levels of oxygen, such as can be experienced during exercise. It works like this: Red beet nitrates (NO3) convert to nitrites (NO2) which then convert to Nitric Oxide (NO).
Red Beet Extract Benefits Include:
• Increased Nitric Oxide Production
• Enhanced Muscle Cell Swelling
• Improved Workout Endurance
2. Cinnulin PF
Cinnulin PF is a water soluble extract of Cinnamomum burmannii, its standardized for double bound Type-A Polymers, primarily tetramers and trimmers – research has indicated a number of positive health benefits. Cinnulin PF is able to mimic the effects of insulin, resulting in reduced body fat and increased lean muscle.
Cinnulin PF benefits:
• Enhanced Lean Muscle and Strength
3. Betaine HCl
Betaine is another compound that works well when combined with creatine. Research conducted in 2010 and published in the Journal of the International Society of Sports Nutrition indicates that following 14 weeks of taking a betaine supplement, test subjects had an increase in power and force in such exercises as: bench press, vertical press, and squat.
Benefits of Betaine Include:
• Enhanced Muscle Cell Volume
• Improved Training Endurance
• Improved Strength
4. Astravar 2.0
Astravar 2.0 consists of Astragin, Rhodiola rosea, BioPerine and red beet extract. Astragin is a plant-based ingredient - it’s actually taken from Panax ginseng and Astragalus, two well-known herbs. Research indicates that Astragin can increase nutrient absorption.
Rhodiola rosea originates in the higher latitudes of the mountains of the Northern hemisphere. Research shows that Rhodiola rosea can promote training endurance.
BioPerine is a standardized extract that comes from Piper nigrum L, or black pepper. BioPerine can enhance nutrient absorption.
Astravar 2.0 Benefits Include:
• Increases Nitric Oxide by Both the NO2 and NO3 Pathways
• Increased Nutrient Absorption
• Improved Training Endurance
Get Top Secret and Get Serious About Your Results!
Serving Size: 1 Scoop (6 Grams)
Servings Per Container: 55
Amount Per Serving
Calcium (As Calcium Silicate) - 40mg 4%
Creatine Synergistic Blend - 4,200mg
Creapure® (Creatine Monohydrate), Creatine MagnaPower, Creatine, AAB 2:1
Strength And Power Booster - 1,580mg
Betaine HCL, Beet Root Extract (Beta Vulgaris)(Root) (High Nitrates), Cinnulin PF® (Cinnamomum Burmannii) (Bark)(Water Extract), Rhodiola Rosea (Root) Extract (Std. 3% Rosavins), Astravar 2.0™ ((Beet Root Extract (Beta Vulgaris)(Root)(High Nitrates), AstraGin™ (Panax Notoginseng Root Ext, Astragalus Root Ext.)), Rhodiola Rosea (Root) Extract, BioPerine® Proprietary (Piper Nigrum) Extract
Mix 1 scoop in 8 ounces (236-295mL) cold water or the beverage of your choice.
Discuss use with your physician before taking this product if you have a medical condition or are taking any medications. Do not use if pregnant or nursing. Must be 18 or older to use this product. Keep away from children.
* No claims found on this web page or in print have been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
No claim or opinion about weight loss, bodybuilding or general health on this web page is intended to be, nor should be construed to be, medical advice. Please consult with a
healthcare professional before starting any weight loss diet or exercise program.


In this work the microstructure analysis of composite from ZrO2 – Ti system were presented. For the preparation of the composite samples nanometric ZrO2 powder stabilized by 3 mol% of Y2O3 and micrometric titanium powder were used. The composites with 10 vol.% addition of titanium particles were prepared by slip casting method. The sintering process was conducted at 1450°C with 2 hours’ dwell time, in the inert atmosphere of argon. The microstructure observations were carried out with the use of SEM and STEM microscopes. The quantitative analysis and stereological characterization were performed. The SEM and STEM observations allowed characterizing the microstructure of composite samples. Especially, the interface between titanium particles and zirconia matrix was described. The growth of the zirconia grains around the Ti rich areas was observed. The increase of the zirconia grains size results from the reaction on the interface between titanium particle and zirconia matrix during the sintering process.


It can be incredibly challenging to make sense of the advice, marketing and commentary on collagen. I find my patients are often left confused concerning their initial steps into collagen supplementation. Albeit daunting, there are a few fundamentals, which can help narrow your approach and ensure you are responding adequately and effectively to your skin's needs.
Collagen as an oral supplement
First and foremost, a popular measure is oral consumption or ingestion of collagen through animal products such as bone broth and gelatine. Collagen being a formative component to the connective tissues found in animals means that invariably, products derived from animals are naturally high in this protein.
A key caveat here is that there’s less evidence to suggest that oral consumption can ostensibly ‘restock’ your collagen stores, particularly when it comes to skin. A more measured and proven approach would be to stimulate your body’s natural production with specific physical, topical and oral practices that can non-invasively induce collagen production.
Studies suggest there is some benefit to having daily animal derived collagen supplements, but more for other aspects of health (gut and joints for example) than purely for skin. Nonetheless, I encourage looking for organic, grass fed options where possible (for bovine derived products) and investigating the source of fish derived products to ensure minimal exposure to heavy metal toxins (which can be a contaminant in some fish derived collagen supplements). Making your own bone broth from a grass fed source is probably the best form of supplementation. After that, there is good evidence for liposomal vitamin C supplements, as Vitamin C is a precursor for collagen production.
Investing in quality skin care products with Vitamin C and Vitamin A will also serve as an effective and proactive first step in your journey towards collagen stimulation, as vitamin C in particular is one of the key precursors for collagen production in the body, both orally and topically. Both vitamins C and A play a very important role in the healing and preservation of connective tissue, encouraging the natural production of collagen in the skin.
There is extensive evidence for the use of both vitamin C and vitamin A in topical skincare products to enhance collagen production in the skin.
Collagen stimulating skincare
When creating the SkinW1 product range, I chose to work with a patented complex of key active ingredients Methylglucoside phosphate and Copper Lysinate/Prolinate, which I had used extensively in clinic for many years, with great results. However I couldn’t find suitable retail products with a high enough percentage of actives to recreate my in-clinic results. The SkinW1 products were born out of a desire to make these ingredients, and my approach, more accessible to everyone.
The active ingredients I have focused on in the Skin W1® product range work to induce the synthesis of key proteins in the dermis involved in the maintenance of collagen type I, collagen type III, tropoelastin and elastin. As we age, our skin's structure to support this collagen deteriorates. My products work to stimulate the protein synthesis with energy provided from the aforementioned key active ingredients. Working together on a molecular level, the Skin W1® range is a great foundation for supporting your collagen production and overall skin health.


This paper reports a digital micro-mirror device (DMD)-enabled real-time multi-channel biosensing system based on angular interrogation surface plasmon resonance (SPR). In the experiments, angular scanning is achieved by a DMD that facilitates SPR measurements using a single-point photodetector. In the four-channel measurement setup, real-time monitoring of bovine serum albumin (BSA) and anti-BSA binding interactions is performed at various concentration levels. The experimental results have verified that the system has a resolution of 3.54 × 10−6 RIU (refractive index unit); and a detection limit of 9 ng/mL. The new DMD-based SPR interrogation system presents a new design route for practical solid-state SPR biosensing with a user-selectable range of interrogation, enhanced signal-to-noise ratio, and fast data throughput.
© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Surface plasmon resonance (SPR) sensor has been widely demonstrated as a practical label-free sensing technology for analyte detection and characterization of biomolecular interactions in the past two decades . It utilizes the evanescent field of a special mode of electromagnetic field propagating at a metal/dielectric interface, i.e., surface plasmon, to measure variations in the refractive index of the dielectric in the proximity of the interface. Most biological species have higher refractive index (RI) comparing to that of water. An increase of RI is typically associated with biomolecular binding as it results in the formation of an ultra-thin organic layer on the metal film . This phenomenon has led to wide applications of SPR in various fields of health and biological sciences, e.g., environmental monitoring , clinical diagnostics , food safety screening , drug discovery , and measurement of optical constants .
The quest for better detection performance has resulted in the development of numerous SPR sensor platforms. The schemes of optical excitation of surface plasmons include attenuated total reflection (prism coupling) , diffraction on periodic metallic gratings (grating coupling)  and nanoparticle-enhanced localized SPR . The modulation approaches used in SPR sensors are based on wavelength , angle  and phase [13–15] interrogation. However, no matter which SPR configuration is used, measurements are basically performed by measuring intensities of light; therefore the performance of SPR sensors are predominantly limited by photon statistics .
Existing SPR solutions utilize an array detector such as CCD to record the intensity data . This imaging array is similar to that used in a scientific camera. However, the use of array detectors presents a significant challenge. They are either quite expensive or typically of less than optimal performance in terms of signal-to-noise (S/N) ratio, rate of response and issues related to inter-pixel cross-talks. In some cases, dead pixels and pixel-to-pixel non-uniformity will further prohibit the possibility of achieving ultimate sensing performance close to the theoretical limit.
It has been predicted that future improvement of SPR sensors will depend mostly on the development of optical detectors with a higher S/N ratio and faster data throughput. The ultimate detection noise is limited by the statistical fluctuations corresponding to the number of detected photons, which suggests that higher photon flux levels are always desired. This objective can only be achieved by using a detector that has large size, wide dynamic range and the capacity of taking temporal average of intensity measurements . Such attributes suggest that single-point photodetectors may be a better light detecting device in future SPR sensors. It has been shown that with a photodiode array detector, the maximum S/N ratio is about 14 times higher than that of the CCD . Single-point photodetector has been used in angular interrogation SPR system to measure SPR response in different angles [19,20]. However, the angular scanning was achieved by mechanical rotation of a laser source or prism coupling system, which is slow, mechanically unstable, and prone to hysteresis.
To realize a high performance SPR system, we have developed a digital micro-mirror device (DMD)-enabled angular interrogation-based SPR sensor configuration using a single-point photodetector. A DMD is a high-speed 2-D light modulation device (max. pattern rate: 32.5 kHz) containing several millions of micromirrors. The unique capability of DMD enables a high-speed, scanless, and programmable SPR sensor design that uses a single-point detector with high S/N ratio, wide dynamic range, and fast response, thereby achieving high-resolution SPR measurements with substantially reduced cost.
All chemicals used in SPR biosensing are purchased from Sigma Aldrich. To generate a monolayer with carboxyl termination, 1 mM 11-mercaptoundecanoic acid (MUA) solution is kept at room temperature to settle overnight. Excess MUA is rinsed with ethanol and followed by deionized water. Freshly prepared 2-(N- Morpholino) ethane sulfonic acid (MES) from mixing equal volume of 400 mM 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and 150 mM N-hydroxysuccinimide (NHS) is then added and incubated for 10 min at room temperature in order to activate the carboxyl terminal on the chip and form covalent bonding with the amine group of the target molecules. For the biosensing experiments that monitor antigen-antibody interaction, 1 mg/mL bovine serum albumin (BSA) is incubated on the chip for 30 min at room temperature. The BSA immobilized on the chip surface is considered as an antigen, while the anti-BSA antibody is added to bind specifically on the BSA. Various concentrations (0.2, 2, 20 µg/mL) of the antibody are injected and incubated for the indicated time at room temperature. Phosphate-buffered saline (PBS) solution is then flown into the reaction chamber to remove the excess antibody. 50 mM NaOH, an alkaline that denatures antibody to remove its binding affinity on antigen, is injected and then PBS is added again. SPR signal is recorded at 20-sec intervals.
2.2 Preparation of the SPR sensor chip
The SPR cell is composed of a right-angle prism made of BK7 glass, a SPR gold chip, and a flow chamber device. The gold chip, fabricated by sputtering, has a gold film with a thickness of approximately 50 nm (refractive index matching oil is used to connect the prism and the chip). The flow chamber device is mounted on the chip surface allowing different sample solutions to make contact with the gold film. For the simultaneous multiple sensing experiments, the flow chamber device contains four channels; each channel acts as an independent cell. The width and length of each flow channel is 0.9 mm and 10.0 mm respectively, i.e., the contact area between the fluid and the sensing surface is 9 mm2 in the calculation of mass sensitivity. The distance between adjacent channels is 0.8 mm.
2.3 Optical configuration
Figure 1 presents the optical configuration of the SPR system, where a He-Ne laser is used as the light source. The laser beam is expanded by a telescope system and directed to the DMD (1140 × 912 pixels, DLP4500VIS, Texas Instrument). The scanning speed of the DMD device is 4.2 kHz. The selection of individual incident angle for SPR excitement is accomplished by selectively switching the columns of micromirrors on the DMD to the “on” or “off” positions. Accordingly, only light rays with the desired angle are reflected to the SPR cell and further to the detector. The single-point photodetector in the system is OPT101 (Monolithic Photodiode and Single-supply Transimpedance Amplifier, Texas Instruments). The size of the detection area is 2.29 × 2.29 mm2 and the measurement bandwidth is 14 kHz. Adjacent columns of micromirrors are turned on successively to conduct angular scanning; and angular interrogation SPR responses are measured successively by the single-point detector. In this respect, angular interrogation of SPR is realized in the time domain. This architecture, with its programmable operation range enabled by the DMD, offers the advantages of angle selection agility, repeatability, and mechanical stability. Light rays selectively reflected by the DMD are subsequently divided by a polarizing beam-splitter. The s-polarized light is focused onto the point detector D1 through a spherical lens (fL3 = 100 mm) to serve as the reference signal. The p-polarized light passes through a cylindrical lens (fCL1 = 50 mm) to form a convergent beam with an incident angle ranging from 70.2° to 76.2° with respect to the sensor surface. After passing through the SPR cell, the reflected light is collimated by another cylindrical lens (fCL2 = 50 mm) to form a collimated light beam, which is subsequently collected by a spherical lens (fL4 = 100 mm) before finally entering the point detector D2.
The proposed SPR sensor architecture offers the capability to perform simultaneous multi-channel biosensing. To realize this, each column of micromirrors on the DMD may be further divided into multiple regions in the horizontal direction. The SPR excitation in different biosensor cells (arranged in the horizontal direction) within the linear array is achieved by selectively activating different micromirror clusters, i.e., turning rows of micromirrors on the DMD to the “on” or “off” positions to excite only the desired SPR cell. The reflected light rays from different SPR channels are focused onto the same point and measured by the single-point detector. This ensures that all sensing elements are addressed sequentially at high speed.
2.4 System control and data analysis
An Arduino board is used to control the SPR system. The output trigger signal of the DMD is utilized for synchronizing the two detectors (D1 and D2) with the pattern sequence. During the period of a single DMD frame, the Arduino board reads ten data points (in voltage) from the detector D1 and D2 in the reference arm and the probe arm respectively. We average the 10 data points from each arm as the final output. Then, the voltage outputs are converted into the radiant powers. The ratio of the power in the probe arm to that in the reference arm is calculated as the final response signal of the SPR system, i.e., power ratio. The collected data are analyzed using a custom-developed software in MATLAB. This process is repeated until all the patterns are displayed successively. Depending on the need, a pattern defined by a rectangle of arbitrary size can be uploaded to the DMD. For real-time multi-channel sensing experiments, the pattern exposure time of the DMD is set to 10 ms, during which the Arduino board reads 10 voltage data points from each detector and calculates the power ratio for the current pattern, or equivalently, the incident angle that it represents. There are 45 angular points in total. Therefore, each complete angular scan for one channel can be completed in 450 ms, which means that for 4 channels the total measurement time is 1.8 s. The total required time for performing the measurement is approximately 20 seconds. This time resolution is currently limited by the data acquisition and transmission speed of the Arduino board, which can be further improved by using a more powerful microcontroller board.
3. Results and discussion
3.1 Characterization of the SPR system
For an angular interrogation SPR system, an SPR response curve indicates the reflected intensity of light versus the incident angle, which can be derived from the three-layer Fresnel equation . The angle yielding the minimum light intensity on the SPR curve is denoted as the resonance angle (RA). Accordingly, we deﬁne that the sensor sensitivity (S) as the RA shift () caused by a small refractive index change (), which can be mathematically expressed in Eq. (1):
Sensor resolution (R) is defined as the lowest detection limit that the SPR sensor can resolve. This parameter is affected by the measurement uncertainty standard deviation (S.D.), which is described in Eq. (2):
To estimate the performance of the SPR system, experiments are performed to measure the RA shift with refractive index variation caused by dissolving glycerol in water. Glycerol-water mixtures with various solute concentrations, i.e., 0% (water), 0.0625%, 0.125%, 0.25%, 0.5%, 1%, 2%, 4% and 8% in weight ratio are injected into the prism coupling system as samples. The corresponding refractive indexes range from 1.3330 to 1.3424 RIU. As shown in Fig. 2(a), the SPR curves are fitted by 3rd-order polynomials [22,23] to the theoretical Fresnel equation , which provides a close fit with an optimal sensitivity . The minimum values of the fitting curves are then determined as RAs. Within the most sensitive region of the SPR response plot, we find a RA shift of 0.0735° for the refractive index change from 1.3330 to 1.3331 RIU (from water to 0.0625% solution), as shown in Fig. 2(b). The fluctuation of the measurement is estimated by monitoring the S.D. of 10 data points collected from a sample containing 8% of glycerol. The monitoring period is 10 min with each data point collected in every minute. The best experimental S.D. is found to be 0.0026°. Taking this as the minimum angular measurement that the system can resolve, the estimated sensor resolution is 3.54 × 10−6 RIU.
For the multi-channel sensing experiments, water is injected to all channels and RAs are recorded as the baseline. Experimental data, i.e., the 15 lowest data points, are fitted by 3rd-order polynomials. Then glycerol-water mixtures with various solute concentrations, i.e., 1%, 2%, 4% and 8% in weight ratio are injected into channel 1, 2, 3, 4 as samples. RAs are recorded and presented in Table 1. The slightly different responses among different channels for the same solution are attributed to the thickness variation of the gold film across the different sensing surfaces. Relative shifts of RAs are plotted in Fig. 3; the results confirm the sensor array’s capability for simultaneously detecting multiple analytes.
To demonstrate multi-channel scanning capability of the DMD-enabled SPR system, a sensor head containing four channels is used to independently monitor BSA antigen-antibody binding at different concentration levels. The experimental results are presented in Fig. 4. Channel 1 is set as the negative control with distilled water flowing inside the chamber during the entire immobilization of BSA. In step 1, surface activation with MES is performed in Channel 2 - 4, where a sharp increase in SPR signal is observed (Fig. 4). The increase in SPR signal is due to a large refractive index difference between the MES and distilled water. Afterwards, the BSA is injected into Channel 4, where in Fig. 4 a corresponding gradual increase of SPR signal can be observed. In step 5, Channel 2 is not blocked with excess MES-activated group, thereby leaving the possibility of downstream covalent protein conjugation. In step 8, the SPR signal of Channel 4 is increased quickly within the first few minutes when the anti-BSA is added, indicating rapid binding of the anti-BSA antibody on the coated BSA surface by molecular binding affinity. The response curves saturate in around 15 min, suggesting that the binding has reached equilibrium. In step 9, the injection of the PBS solution, removing all unbound anti-BSA antibody, reveals that the true SPR signal change is solely due to the antigen-antibody interaction, rather than the sum of antigen-antibody interaction plus reflective index difference in anti-BSA antibody solution. The small change in SPR signal in Channel 1 - 3 suggests that there is non-specific adsorption of anti-BSA antibody on the chip surface. To prepare the SPR sensing surface for reuse, SPR signal is recorded during and after NaOH circulation. In step 9, the signal returns to the original value in Channel 1, 3 and 4, suggesting the adsorbed and bound anti-BSA antibody are dissociated from the BSA-coated surface (The final signal in Channel 4 is slightly higher than the original value; this is due to the fact that the adsorbed and bound anti-BSA antibody are not fully dissociated from the BSA-coated surface during the NaOH circulation), while the signal remains unchanged in Channel 2, suggesting the anti-BSA antibody is covalently bound on the unblocked MES-activated SPR surface and the anti-BSA antibody in Channel 2 cannot be dissociated simply by the reduction of binding affinity with a pH change.
As a demonstration, we apply our SPR system to measure quantitative real-time antigen-antibody interaction in four channels simultaneously. Concentration-dependent SPR responses obtained from the four channels are presented in Fig. 5. After surface functionalization by the BSA antigen, samples of anti-BSA antibody at various concentration levels (0, 0.2, 2, 20 µg/mL) are injected into the different channels, as shown in Fig. 5(a); and Fig. 5(b) is the summary of the net change in SPR signal of anti-BSA antibody addition in Fig. 5(a).
The measured SPR angular shift of 0.2 μg/mL (or 200 ng/mL) is 0.0456 as shown in Fig. 5(b). On the other hand, the steady baseline of PBS injection shows an S.D. of 0.002. The detection limit of the anti-BSA antibody detection is calculated according to the established equation: Detection Limit = Concentration of Biomolecule / Sensor Response Measurement Stability. Therefore, it is 200 ng/mL / 0.0456 × 0.002 = 9 ng/mL, which is similar to other SPR systems for bio-sensing on BSA antigen-antibody binding [24,25]. Since each flow channel in our device has a volume of 0.0108 mL, the corresponding system mass sensitivity is calculated to be (9 ng/mL 0.0108 mL) / 9 mm2 = 10.8 pg/mm2. The mass sensitivity ranges from 0.5 to 10 pg/mm2 in other reported SPR systems with a similar RIU of 10−6, where lower mass sensitivity (0.5 pg/mm2) is indeed achieved by pre-coating biomolecules in a 3-D dextran matrix (CM5 chip) instead of monolayer format reported here [26,27]. To illustrate the repeatability of the sensing system, the anti-BSA antibody and NaOH are injected into the system for measurement; and the experiments are repeated three times. The results are presented in Fig. 6. From Fig. 6, one may observe that the system is highly repeatable, where measured curves in all three experiments have similar rising and decreasing traits. For the analysis of reproducibility, coefficient of variation (CV) is introduced. CV is the analysis of the intermediate precision of a single system over multiple detections, and measure variability of CV percentage (CV%) < 5% is considered as an accurate detection . CV% is calculated as (Standard Deviation / Mean) 100 = (0.008/0.473) 100 = 1.7%, which supports high reproducibility in our biosensing measurement.
In summary, we have developed a DMD-enabled real-time multi-channel biosensor system based on angular interrogation of the Kretchmann configuration. Notably, the system employs a single-point detector that simultaneously optimizes the system S/N ratio, provides a wide dynamic range and fast response. The experimental results have confirmed that the system has a resolution of 3.54 × 10−6 RIU; and a detection limit of 9 ng/mL, calculated based on real-time monitoring of BSA/anti-BSA binding interactions at various concentration levels using a four channel biosensor array. Further enhancement of measurement resolution can be achieved by increasing the laser excitation power or optimizing the shot-noise limited performance of the single-point detector.
HKSAR Research Grants Council (RGC) General Research Fund (GRF) (412613 and 14206517); CUHK Direct Grant (CUHK 3132798 & 4053100); AoE Scheme Funding (AoE/P-0/12); HKSAR Innovation and Technology Commission (ITS/428/17FP).
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The Role of Tryptophan and Its Derivatives in Elucidating A PCET Mechanism in the Model Protein Azurin
Long, Hanna LK
The role and properties of electron-rich tyrosine in the proton-coupled electron transport (PCET) pathway has been extensively studied, specifically relating to ribonucleotide reductase. Tryptophan is another electron-rich amino acid that can be derivatized into unnatural amino acids (UAAs) to further explore the mechanism of PCET. The purpose of this study is to computationally study the properties of tryptophan and its derivatives, modeled as simplified indole rings, to rationalize key experimental findings. Calculations were performed using density functional theory (DFT) to provide information on structure, energetics, and properties in a reliable, efficient manner. Ionization potentials of the halogenated and hydroxylated indole rings were studied with and without a solvent environment to understand certain features of the experimentally derived Pourbaix (potential vs. pH) diagram. Spin density distributions of the radical cations were examined regarding their relationship to the signature fine structure in the electron paramagnetic resonance spectra of the fluorinated derivatives of tryptophan. Electrostatic potential maps were calculated to provide a simple yet reliable means of evaluating charge distribution in the neutral and radical species. Results indicate that DFT mimicked the trends found in the Pourbaix diagram and gave insight on the properties of UAAs such as charge stabilization. Ultimately, a computationally-guided synthesis of an UAA, with its properties explicitly known, into the bacterial protein azurin could provide further insight into the PCET pathway.
Long, Hanna LK. (April 2021). The Role of Tryptophan and Its Derivatives in Elucidating A PCET Mechanism in the Model Protein Azurin (Honors Thesis, East Carolina University). Retrieved from the Scholarship. (http://hdl.handle.net/10342/9015.)
Long, Hanna LK. The Role of Tryptophan and Its Derivatives in Elucidating A PCET Mechanism in the Model Protein Azurin. Honors Thesis. East Carolina University, April 2021. The Scholarship. http://hdl.handle.net/10342/9015. September 26, 2023.
Long, Hanna LK, “The Role of Tryptophan and Its Derivatives in Elucidating A PCET Mechanism in the Model Protein Azurin” (Honors Thesis., East Carolina University, April 2021).
Long, Hanna LK. The Role of Tryptophan and Its Derivatives in Elucidating A PCET Mechanism in the Model Protein Azurin [Honors Thesis]. Greenville, NC: East Carolina University; April 2021.
East Carolina University