bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental problems in the application of UV/visible based methods as the quantification tool for the entrapped/released insulin from PLGA carriers
Authors: Lassalle V.L. , Ferreira M.L. 
Published: March 2009

AbstractBACKGROUND: Controlled release of medicaments from biodegradable polymers remains the most convenient way for their sustained release. Although a number of articles have been published, experimental work involving the preparation of polymer‐based carriers and release procedures are not described with sufficient level of detail to allow other researchers to reproduce the experiments and to compare published results with their own. In this contribution the experimental background of the entrapment and release of insulin from PLGA carriers is described and the problems found at each step related to UV/Visible method used to quantify them are addressed in detail.RESULTS: The quantification of entrapped insulin by UV/visible methods was affected by aggregation. The design of the release experiment influenced the results regarding the entrapment efficiency (EE) and the maximum percentage of released insulin. It was also found that the presence of colloidal polymeric particles, insufficient centrifugation times and the kind of solvent used in the release test might lead to mistakes in the percentage of liberated insulin when UV/visible based methods are employed.CONCLUSIONS: This contribution demonstrates that serious discrepancies in the EE and percentage of released protein may arise if some key experimental factors are not taken into account. Therefore, the analysis presented here tries to point out important aspects of this topic currently not reported, unnoticed or not properly analyzed in the open literature. The results are useful for the entrapment of any protein on any polymeric device using UV/visible based methods to quantify them. Copyright © 2009 Society of Chemical Industry
Synthesis of 3‐substituted 4H‐1‐benzothiopyran‐4‐ones
Authors: Nakazumi Hiroyuki , Endo Takashi , Sonoda Hikaru , Kitao Teijiro 
Published: March 2009

Abstract3‐Substituted 2‐phenyl‐4H‐1‐benzothiopyran‐4‐ones (thioflavones) were prepared to test antimicrobial activity. It was found that 3‐(phenyl)thiochromone derivatives (isothioflavones) were prepared by the Meerwein reaction of thiochromone with p‐nitrobenzenediazonium ion. 3‐(Formyl)thioflavone exhibits weak antimicrobial activity against Trichophytons and Candida.
Stabilization of Liposomes by Polyelectrolytes: Mechanism of Interaction and Role of Experimental Conditions
Authors: Rinaudo Marguerite , Quemeneur François , Pépin‐Donat Brigitte 
Published: March 2009

Abstractζ‐potential measurements on LUVs allow to evidence the influence of pH, ionic salt concentration, and polyelectrolyte charge on the interaction between polyelectrolyte (chitosan and hyaluronan) and zwitterionic lipid membrane. First, chitosan adsorption is studied: adsorption is independent on the chitosan molecular weight and corresponds to a maximum degree of decoration of 40% in surface coverage. From the dependence with pH and independence with MW, it is concluded that electrostatic interactions are responsible of chitosan adsorption which occurs flat on the external surface of the liposomes. The vesicles become positively charged in the presence of around two repeat units of chitosan added per lipid accessible polar head in acid medium down to pH = 7.2. Direct optical microscopy observations of GUVs shows a stabilization of the composite liposomes under different external stresses (pH and salt shocks) which confirms the strong electrostatic interaction between the chitosan and the lipid membrane. It is also demonstrated that the liposomes are stabilized by chitosan adsorption in a very wide range of pH (2.0 < pH < 12.0).Then, hyaluronan (HA), a negatively charged polyelectrolyte, is added to vesicles; the vesicles turn rapidly negatively charged in presence of adsorbed HA Finally, we demonstrated that hyaluronan adsorbs on positively charged chitosan‐decorated liposomes at pH < 7.0 leading to charge inversion in the liposome decorated by the chitosan‐hyaluronan bilayer. Our results demonstrate the adsorption of positive and/or negative polyelectrolyte at the surface of lipidic vesicles as well as their role on vesicle stabilization and charge control.
Thermogravimetric and weathering study of novolac resin composites reinforced with mercerized bamboo fiber
Authors: Das M. , Prasad V.S. , Chakrabarty D. 
Published: March 2009

AbstractThe effect of alkali treatment of bamboo strips on the thermal and weathering properties of unidirectional bamboo strips‐novolac resin composites were investigated in this work. Both alkali treated and untreated bamboo fiber‐reinforced composites were fabricated. All types of composite specimens were subjected to accelerated weathering and the % water absorption and dimensional changes were recorded after 120 h immersion in water at room temperature and atmospheric pressure and further characterized by flexural property measurements. The composites were also subjected to exposure at 100% humidity and UV exposure (sun light) for 75 h. The results showed that the composites with treated bamboo strips showed a better weathering characteristics compared with the untreated ones. Thermogravimatric analysis of all the samples indicated better thermal properties of alkali treated samples. These findings confirmed the improved interfacial interactions arising from covalent bonds between the alkali treated bamboo fibers and novolac resin. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers
Adaptation of polystyrene/multi‐wall carbon nanotube composite properties in respect of its thermal stability
Authors: Slobodian Petr , Králová Daniela , Lengálová Anežka , Novotný Radko , Sáha Petr 
Published: March 2009

AbstractPolystyrene (PS)/multi‐wall carbon nanotube (MWCNT) nanocomposites were prepared by melt mixing and by coagulation of PS/MWCNT sonicated dispersion. Before mixing and coagulation particles of MWCNT were covered with PS nanospheres by microemulsion polymerization to increase their dispersibility and compatibility with the matrix. Microemulsion polymerization was carried out under sonication in the presence of surfactants and a cross‐linking agent. The structure of modified MWCNT filler was revealed by SEM and TEM microscopy analyses. They show that PS is well grafted onto surface of MWCNT in form of ca 30 nm nanospheres or as ca 3–8 nm PS film layer. Significant changes in properties were recorded mainly for the coagulated sample. Although no shift of Tg was recorded for the melt mixed composite, the coagulated sample shows an increase by 9°C. Also the reinforcing effect of MWCNT was more pronounced for the same method of preparation (further supported by the filler modification). The creep response of this material shifts to longer times not only in the Tg area, but also as low as 70°C below it, which is perceived as an improvement of temperature stability (the same properties kept for a longer time). This was also proved by the increase of creep modulus, and consequently by the prolonged time needed to reach the same tensile creep compliance after aging. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Tyrosine phosphoproteome of hamster spermatozoa: Role of glycerol‐3‐phosphate dehydrogenase 2 in sperm capacitation
Authors: Kota Venkatesh , Dhople Vishnu M. , Shivaji Sisinthy 
Published: March 2009

AbstractCapacitation confers on the spermatozoa the competence to fertilize the oocyte. At the molecular level, a cyclic adenosine monophosphate (cAMP) dependent protein tyrosine phosphorylation pathway operates in capacitated spermatozoa, thus resulting in tyrosine phosphorylation of specific proteins. Identification of these tyrosine‐phosphorylated proteins and their function with respect to hyperactivation and acrosome reaction, would unravel the molecular basis of capacitation. With this in view, 21 phosphotyrosine proteins have been identified in capacitated hamster spermatozoa out of which 11 did not identify with any known sperm protein. So, in the present study attempts have been made to ascertain the role of one of these eleven proteins namely glycerol‐3‐phosphate dehydrogenase 2 (GPD2) in hamster sperm capacitation. GPD2 is phosphorylated only in capacitated hamster spermatozoa and is noncanonically localized in the acrosome and principal piece in human, mouse, rat, and hamster spermatozoa, though in somatic cells it is localized in the mitochondria. This noncanonical localization may imply a role of GPD2 in acrosome reaction and hyperactivation. Further, enzymatic activity of GPD2 during capacitation correlates positively with hyperactivation and acrosome reaction thus demonstrating that GPD2 may be required for sperm capacitation.
Outcome of children with pulmonary lymphangiectasis
Authors: Mettauer Nicole , Agrawal Shruti , Pierce Christine , Ashworth Micheal , Petros Andy 
Published: March 2009

AbstractPulmonary lymphangiectasis (PL) is a very rare developmental defect of the lungs, which has previously been reported to have a very poor prognosis. However, recent reports have suggested improved outcomes, possibly as a result of advances in neonatal and pediatric intensive care medicine. We performed a retrospective study on the outcome of children with PL between 1990 and 2008 referred to our tertiary center. Seven patients with histologically proven PL were identified over the 18‐year period. Six patients presented in the neonatal period and one patient at 7 months of age, all of them requiring intensive care treatment. Three neonatal patients required extracorporeal membrane oxygenation (ECMO). Six of the seven patients did not survive including all those who received ECMO. Two of the six non‐survivors died of other causes than their underlying disease. The only survivor had an antenatal diagnosis of hydrops and required in utero chest drain insertion. Postnatally he was managed with maximal medical treatment for bilateral pleural effusions and persistent pulmonary hypertension. A 7‐month follow‐up showed this infant to be doing well. In conclusion overall the prognosis of congenital PL remains poor. The one survivor demonstrates that this condition is survivable with aggressive intervention and as current evidence suggests gradual improvement of symptoms may occur over time, and that maximal medical treatment remains warranted. Pediatr Pulmonol. 2009; 44:351–357. © 2009 Wiley‐Liss, Inc.
The Brichos domain of prosurfactant protein C can hold and fold a transmembrane segment
Authors: Johansson Hanna , Eriksson Maria , Nordling Kerstin , Presto Jenny , Johansson Jan 
Published: March 2009

AbstractProsurfactant protein C (proSP‐C) is a 197‐residue integral membrane protein, in which the C‐terminal domain (CTC, positions 59–197) is localized in the endoplasmic reticulum (ER) lumen and contains a Brichos domain (positions 94–197). Mature SP‐C corresponds largely to the transmembrane (TM) region of proSP‐C. CTC binds to SP‐C, provided that it is in nonhelical conformation, and can prevent formation of intracellular amyloid‐like inclusions of proSP‐C that harbor mutations linked to interstitial lung disease (ILD). Herein it is shown that expression of proSP‐C (1–58), that is, the N‐terminal propeptide and the TM region, in HEK293 cells results in virtually no detectable protein, while coexpression of CTC in trans yields SDS‐soluble monomeric proSP‐C (1–58). Recombinant human (rh) CTC binds to cellulose‐bound peptides derived from the nonpolar TM region, but not the polar cytosolic part, of proSP‐C, and requires ≥5‐residues for maximal binding. Binding of rhCTC to a nonhelical peptide derived from SP‐C results in α‐helix formation provided that it contains a long TM segment. Finally, rhCTC and rhCTC Brichos domain shows very similar substrate specificities, but rhCTCL188Q, a mutation linked to ILD is unable to bind all peptides analyzed. These data indicate that the Brichos domain of proSP‐C is a chaperone that induces α‐helix formation of an aggregation‐prone TM region.
Effects of Mo back contact thickness on the properties of CIGS solar cells
Authors: Kamikawa‐Shimizu Yukiko , Shimada Shuuhei , Watanabe Manabu , Yamada Akimasa , Sakurai Keiichiro , Ishizuka Shogo , Komaki Hironori , Matsubara Koji , Shibata Hajime , Tampo Hitoshi , Maejima Keigou , Niki Shigeru 
Published: March 2009

AbstractEffects of Mo back contact thickness on the photovoltaic properties of CIGS solar cells were investigated. When the Mo was thin, an increase in series resistance and leakage current adversely affected the FF (fill factor) in solar cells fabricated using the Mo layers. On the other hand, when the thickness of the Mo layer was as thick as 0.8 μm, sodium out‐diffusion from the SLG decreased. The resulting reduced sodium concentration in CIGS films grown on top of the contact layers resulted in reduced open circuit voltage (VOC). As a consequence of the tradeoff between the decreased sodium diffusion for thicker Mo layers and reduced FF in thin Mo layers, the optimal Mo thickness was found to be 0.2 μm. Water vapor introduction during the deposition of the CIGS absorber layer was found to be effective in improving overall photovoltaic properties especially in solar cells with thin Mo back contacts. With water vapor introduction, cell efficiencies as high as 16.9% and 16.0% were obtained with Mo thicknesses of 0.2 μm and 0.07 μm, respectively. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fourier transform infrared surface photovoltage spectroscopy for the investigation of mid‐infrared semiconductor lasers
Authors: Sharma Tarun K. , Fox Natasha E. , Hosea T. J. C. 
Published: March 2009

AbstractA novel application of the surface photovoltage spectroscopy (SPS) technique, using a Fourier transform infrared (FTIR) interferometer, has been developed for the investigation of narrow‐gap mid‐infrared semiconductor quantum well (QW) laser structures. We demonstrate the FTIR‐SPS technique at room temperature for a GaInSb/AlGaInSb type I QW laser structure, grown on GaAs, emitting in the mid‐infrared at ∼4 μm, revealing an unambiguous detection of the ground and excited state transitions of the GaInSb QW, as well as the AlGaInSb barrier bandgap energy. As a further corroboration of the new technique, the FTIR‐SPS spectrum of a ∼1.5 μm communication laser structure has also been measured and shown to be in good agreement with conventional grating‐based electro‐modulated reflectance and SPS spectroscopic measurements on this sample. A detailed numerical analysis of the room temperature FTIR‐SPS results for the mid‐infrared semiconductor laser structure is also presented, including a comparison with theoretical predictions of the QW transition energies. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Physicochemical Properties of Banana Starch Oxidized under Different Conditions
Authors: Sánchez‐Rivera Mirna M. , Méndez‐Montealvo Guadalupe , Núñez‐Santiago Carmen , de la Rosa‐Millan Julian , Wang Ya‐Jane , Bello‐Pérez Luis A. 
Published: March 2009

AbstractStarch isolated from unripe bananas was oxidized under different conditions and the physicochemical properties of the oxidized banana starches were characterized. It was found that pH was the dominating factor in the formation of carboxyl groups. Higher yields of carboxyl groups were found when oxidized starch was prepared at pH 11.5 as compared with 7.5. Longer reaction time also produced a higher carboxyl value. Maltese crosses were still visible in the polarized light micrographs of oxidized banana starch, indicating that the ordered arrangement of starch molecules was not altered. The diffraction pattern of both native and oxidized banana starches was a mixture of A‐ and B‐types. No difference was noted in the absorbance ratio as measured by infrared spectroscopy between the oxidized banana starches at both pHs. The onset and peak gelatinization temperatures increased and gelatinization range decreased with increasing pH during the oxidation. For pasting properties, viscosity significantly decreased during heating and cooling with the most drastic reduction noted for the sample oxidized at pH 11.5. All starches showed a non‐Newtonian shear‐thinning behavior. The oxidation reaction that incorporated chemical groups produced a softer system in banana starch due to the possible incorporation of more water molecules in its structure.
Patterns of rapid and extremely rapid (avalanche) sedimentation: implications for marine oil and gas generation
Authors: Lisitsyn A.P. 
Published: March 2009

AbstractAccording to recent data from seas and oceans, marine sediments have extremely uneven thicknesses varying from tens of meters to 15–20 km. Sedimentary material is localized mainly at three global levels: river–sea boundary (zero level, continental base of erosion), continental rise (3–5 km), and trenches (6–11 km). As a result of extremely rapid (“avalanche”) deposition in trenches, large amounts of organic matter accumulate in bottom sediments, thus providing their high petroleum reservoir potential. Sediments in areas of rapid sedimentation have a particular rheology, which causes them to move downslope hundreds of kilometers on the sea floor. Continental rise is a global area where gravitites accelerate, with their potential energy due to a depth difference of 3 to 5 km. Global-scale drift of sedimentary masses driven by eustatic sea level change produces very large deposition zones rich in oil and gas at the continental rise (global piedmont), i.e., at the second level. Predicted oil and gas fields of this kind have been discovered recently at sea depths over 3.5 km, which lie in stock for future development through the 21st century.
Variation in the Chemical Composition of Mangels
Authors: Wood T. B. , Berry R. A. 
Published: March 2009

Below is a brief summary of the chief points of interest which our investigations appear to have suggested so far:That the most convenient method of sampling roots for analysis is to remove a core from each root, and that when using this method at least 50 roots must be cored in order to obtain a sample representing the composition of the bulk of roots grown on a field.That a large proportion of the commonly grown strains of mangels may be assigned to one or other of five types.That of these types, four have their cropping power and percentage of dry matter so nearly in inverse proportion that they yield practically the same weight of dry matter per acre.That the fifth type, Long Bed, yields considerably more dry matter per acre than the other four varieties.That large roots on the average contain more water and less dry matter than smaller ones.That there is a considerable variation in the composition of mangels from year to year, probably depending on such conditions as rainfall and sunshine at particular periods of growth.That manurial treatment causes distinct variations in composition, the most noticeable point being that excessive applications of nitrogen delay ripening and decrease the percentage of dry matter.That different farms grow roots of different composition.That there is very great variation among individual roots of the same variety grown side by side, in content of dry matter, sugar, and nitrogen, and in size, shape, colour; in fact, in all the characters which we have been able to observe.That there is so little correlation between the different characters that it is possible to pick out for seed-mothers large roots containing high percentages of dry matter rich in any desired constituent, and it is suggested that, from analogy with the sugar beet, continuous selection carried out in this manner may result in improvement in any desired direction.That since colour, shape, and specific gravity of root or of juice are shown not to be correlated with percentage of dry matter, sugar, or nitrogen, selection for these characters is not likely to lead to any improvement.
The Action of Heat and Antiseptics on Soils
Authors: Pickering Spencer Umfreville 
Published: March 2009

When soils are treated with antiseptics, such as carbon disulphide, chloroform, benzene, ether or paraffin oil, they undergo chemical change, and the soluble organic matter in them is increased, just as in case of their being heated; they also exhibit the same inhibitory effect on the germination of seeds that heated soils do.The different antiseptics differ in the intensity of their action, but the inhibitory substance formed is probably the same in all cases, and also the same as that formed by heat, for the quantity formed has the same effect on seeds, whether produced by antiseptics or by heat.On keeping treated soils for a few weeks at a summer temperature, some of the organic matter which was rendered soluble becomes insoluble, and the inhibitory action is reduced. This is also the case with heated soils, especially when repeatedly watered; though with unheated soils under similar conditions the soluble organic matter increases.The treatment of soils with antiseptics induces a change equivalent to that obtained by heating the soil to 60°—75°, and this may be sufficient to account for the increased growth observed in plants grown in them.The production by heat of a substance inhibitory to germination appears to be a property common to all soils, twelve instances having been examined: the proportion of it formed depends on the increase in the amount of organic matter rendered soluble by heating; but the actual amount of the soluble organic matter in the heated soil is not always a criterion as to the intensity of its inhibitory action, and still less is the amount of soluble organic matter originally present in the unheated soil, though in the majority of cases it may be so. There appears to be no connexion between the fertility of a soil and the extent to which it is altered by heating.Soils in their natural state appear generally to contain a certain amount of this inhibitory substance, as they act less favourably towards germination than pure water does: whether in any cases soils can act more favourably than water—as the earlier experiments had indicated they could—is open to doubt, but the probability is in favour of their doing so. So far as the instances now examined are concerned, the richer soils, and those containing most soluble organic matter, are slightly less favourable to germination than the poorer soils.
The Feeding Value of Mangels
Authors: Wood T. B. 
Published: March 2009

The paper describes attempts to test the following points—the comparative feeding value of Yellow Globe and Long Red mangels as constituents of a liberal fattening diet, the comparative feeding value of Golden Tankard and Long Red mangels, also as constituents of a fattening diet, and the comparative feeding value of Yellow Globe and Long Red mangels for store cattle.The results point to the following conclusions:The rates of fattening of individual animals vary so greatly that little reliance can be placed on the results of single experiments with the small numbers of animals commonly employed in feeding tests.The feeding values of Long Reds and Yellow Globes were compared on seven occasions, and the results discussed according to the ordinary methods used in the theory of probabilities.