bluuebunny/crossref_metadata_2025 huggingface dataset:
The ternary Ga‐Pd‐Sb phase diagram: A system relevant to contact materials for GaSb
Authors: Richter K. W. , Ipser H.
Published: July 2012

The phase relationships of GaSb in the ternary system Ga‐Pd‐Sb were studied for an isothermal section at 500°C by means of X‐ray diffraction (XRD) and electron probe micro analyses (EPMA). Eight invariant ternary phase reactions, i.e. three quasibinary eutectic reactions, three ternary transition reactions and two ternary eutectics were identified by means of differential thermal analyses (DTA). All experimental phase diagram informations were combined to construct a complete reaction scheme (Scheil diagram) in the investigated composition area and the liquidus surface was derived based on the results of the DTA measurements. The gallium‐rich part of the limiting binary Ga‐Pd system was reinvestigated by means of DTA and XRD.
Experimental investigations of the enthalpies of formation of Zr‐based metallic amorphous binary and ternary alloys
Authors: Turchanin A. A. , Tomilin I. A.
Published: July 2012

The enthalpies of formation of amorphous Zr‐Cu, Zr‐Ni, Zr‐Cu‐Al, Zr‐Ni‐Al and Zr‐Ni‐Ti alloys from pure crystalline elements at 298 K were measured in an isoperibolic Calvet‐type solution calorimeter which is operating in the temperature range 298–1300 K. The alloys of the following compositions were investigated:

Zr1‐xCux (x = 0.30, 0.40, 0.50, 0.60, 0.65, 0.70)

Zr1‐xNix (x = 0.33, 0.40, 0.67)

(Zr0.65Cu0.35)1‐x (Zr0.65Cu0.35)x (x = 0, 0.10, 0.20, 0.40, 0.50, 0.60, 0.70, 0.80)

(Zr0.60Ni0.40)1‐x (Zr0.60Ni0.40)x (x = 0, 0.125, 0.250, 0.374, 0.500)

(Zr0.33Ni0.67)1‐x (Ti0.33Ni0.67)x (x = 0, 0.15, 0.30, 0.45)

The results are discussed in comparison with thermodynamic data about enthalpies of formation of liquid alloys and intermetallic compounds available in the literature. In all investigated systems the enthalpies of formation show great negative values and a strong chemical interaction between the atoms.
Measurements of thermophysical properties of solid and liquid Fe‐Ni alloys
Authors: Seifter A. , Pottlacher G. , Jäger H. , Groboth G. , Kaschnitz E.
Published: July 2012

Enthalpy, resistivity and density as a function of temperature of binary Fe‐Ni alloys have been measured by a fast resistive pulse heating technique. Six different concentrations, including Invar‐type alloy, have been investigated to cover the entire range of the phase diagram. The temperature range was from room temperature to 2400 K.
Thermodynamic study of CaO‐Sb2O3 system by emf method
Authors: Katayama I. , Kemori N. , Denholm W. T.
Published: July 2012

The emf of the following galvanic cells with stabilized zirconia solid electrolyte was measured to determine the calcium antimonites which can coexist with liquid antimony in the temperature range 930−1100 K; (−)Pt, Re|Sb(1), two phases in CaO‐Sb2O3 system | O2− | air, Pt(+) Equilibrium oxygen pressures are obtained as follows:

3/2RT In PO2/kJ = −687.5+0.2433 T/K±0.6 for Sn, Sb2O3;

−817.8+0.2402T/K±0.6 for Sb(1), 4CaO·Sb2O3, CaO;

−800.5+0.2463T/K±0.6 for Sb(1), 4CaO·Sb2O3, 2CaO·Sb2O3;

−762.5+0.2828T/K±0.5 for Sb(1), 2CaO·Sb2O3, CaO·Sb2O3;

−690.5+0.2436T/K±1.0 for Sb(1), CaO·Sb2O3, Sb2O3.

Standard Gibbs free energies of formation of double oxides coexisting with liquid antimony from CaO(s) and Sb2O3 are derived as follows:

4CaO(s)+Sb2O3(1)=4CaO·Sb2O3(s); ΔG°/kJ = −130.3−0.0031 T/K

2CaO(s)+Sb2O3(1)=2CaO·Sb2O3(s); ΔG°/kJ = −121.7−0.00005 T/K

CaO(s)+Sb2O3(1)=CaO·Sb2O3(s); ΔG°/kJ = −98.3+0.0197 T/K.

The activities of Sb2O3 and CaO in the two phase regions at 1000 and 1100 K are derived and the most stable double oxide is CaO·Sb2O3 in this system. By an X‐ray diffractometry, it was found that 3CaO·Sb2O3(s) cannot coexist with Sb(1).
Development of Si‐B‐C‐N ceramics supported by phase diagrams and thermochemistry
Authors: Seifert Hans Jürgen , Lukas Hans Leo , Aldinger Fritz
Published: July 2012

To explain the crystallization behaviour and phase relationships of precursor derived Si‐B‐C‐N ceramics, In (pN2)‐Tdiagrams were calculated. The results can be used to optimize the chemical composition and the physico‐chemical conditions for heat treatment. Stabilization of specific phase assemblages requires careful adjustment of the N2partial pressure during heating and cooling. The high thermal stability of silicoboron carbonitrides can be explained by their particular microstructure and the resulting stabilization of Si3N4.
Electronic conduction in cryolite‐alumina melts
Authors: Haarberg G.M. , Thonstad J. , Egan J.J. , Oblakowski R. , Pietrzyk S.
Published: July 2012

Previous work by the authors has shown that electrons are an important constituent of cryolite melts saturated with alumina and in contact with aluminum. This has a negative effect on the current efficiency of aluminum production in industrial cells.

In the present paper, methods used to measure electronic conduction, electron mobilities, and electron concentrations in cryolite alumina melts (NaF/AlF3 molar ratio=3) will be reviewed. New results will then be reported on electronic conduction in melts with a NaF/AlF3 molar ratio of 2.4 at various sodium activities. In particular, a ratio nearer to that used in industrial cells was examined. AC resistance measurements were performed on cryolite‐based alumina melts equilibrated with aluminum‐silver alloys between 967 and 1037°C.

The results were used to estimate the effect of electrons on current efficiency in cells used for the production of aluminum. Equations for the current efficiency formerly used by the authors are reviewed and calculations based on the new results are presented. In general, current efficiencies between 94.5% and 99% were obtained.
The In‐Sn‐Zn system
Authors: Xie Y. , Schicketanz H. , Mikula A.
Published: July 2012

DTA measurements, lattice parameter investigations and micro‐probe analyses were performed on fourty ternary In‐Sn‐Zn alloys to determine the phase diagram. The investigations were carried out along three cross‐sections with a constant Sn to Zn ratio of 2:1, 1:1 and 1:2. A vertical section with 10 at% In was also measured. Based on this data as well as thermodynamic and phase diagram data of the three binary systems from literature the ternary phase diagram was optimised by using different models.

Since some of these alloys might be a useful candidate for lead free solder materials the temperature dependence of the thermo‐emf was measured for some compositions.
Aerogels: Production, modification and applications
Authors: Burger T. , Fricke J.
Published: July 2012

Aerogels are highly porous, nanostructured sol‐gel derived materials. In the nineteen sixties and seventies highly transparent and monolithic silica aerogels have mainly been used in Cherenkov detectors to determine the momentum of relativistic particles. After an increasing availability of granular SiO2‐aerogels from a BASF pilot plant in the eighties, applications of these materials in solar architecture (especially for daylighting purposes and transparent thermal insulations) have been investigated. Today, additionally research focuses on metalloxide‐, organic‐ and carbon‐aerogels. The applications range from acoustic impedance matching layers in ultrasonic transducers to subtrates for catalytic materials, transparent molds for melt casting, sensors, electrodes in supercapacitors and fuel cells as well as capture of cosmic dust and micrometeorits. Particularly interesting with respect to mass applications is the use of aerogel powder in the evacuated superinsulation of the BMW latent heat storage device which can be employed to defrost the windshield or to preheat the engine. A broad availability of cheap aerogels is expected from a production process based on subcritical drying (versus supercritical extraction in an autoclave) currently persued by Hoechst AG.
Reversible molecular adsorption as a tool to observe freezing and to perform design of heteropolymer gels
Authors: Tanaka Toyoichi , Enoki Takashi , Grosberg Alexander YU. , Masamune Satoru , Oya Taro , Takaoka Yukikazu , Tanaka Kazunori , Wang Changnan , Wang Guoqiang
Published: July 2012

Protein folding is one of the most challenging problems in science. How can polymers memorize and fold into unique conformations? How can they recognize molecules, catalyze chemical reactions, transfer molecular information, and create motions! The principle behind these mechanisms lies in the concept of thernodynamically stable phases of heteropolymers. Recent theories predict that the collapsed phase should be further classified into three phases: freely fluctuating like liquid, frozen in degenerate conformations, and frozen in a unique conformation. This yields a clue on how one can attempt creation artificial polymers capable to mimic some of the protein properties and functions. The reversible adsorption of target molecules is suggested as a primary means to achieve this goal. Target molecules with multiple adsorption sites play a twofold role. First, they mediate specific interactions between monomers and thus serve as “gluons”. Second, monitoring the adsorption provides the experimental possibility to test directly on monomer contacts, which is directly related to observation of the order parameter associated with heteropolymer freezing transition. A slight change in the backbone conformation alters the spacial arrangement of the group, allowing for reversible adsorption and release. Polymer gels are developed that can reversibly change their affinity to target molecules by orders of magnitude. The gels are made of copolymers of backbone monomers that can reorganize themselves through thermal volume phase transition and of monomers that can attract the target at multiple contact points. Further the gels “imprinted” with the target showed a marked increase in the affinity, thus mimicing a protein‐like ability to memorize and recognize certain target.
Polymer gel template for porous TiO2 production
Authors: Caruso R. A. , Giersig M. , Willig F. , Antonietti M.
Published: July 2012

Porous networks of titanium dioxide have been produced using polymer gels as templates. Titanium dioxide is well known for its semiconductor and catalysis properties, and for being a very stable material. The porous polymer gels are produced in aqueous surfactant solutions. Following cleaning and solvent exchange procedures the titanium precursor can be incorporated within the gel and hydrolysed. The organic material is removed during calcination leaving the structured titanium dioxide. Both the rutile and anatase forms of titanium dioxide can be produced. The resulting crystal structure and the surface area of the oxide are important for determining its scope of application. These properties have been studied using electron microscopy, X‐ray diffraction and gas sorption.
Influence of surfactant on the gelation of novel ethylene glycol esters of silicic acid
Authors: Sattler K. , Gradzielski M. , Mortensen K. , Hoffmann H.
Published: July 2012

The sol‐gel transition of a novel glycol ester of ortho silicic acid is investigated by small angle neutron scattering technique. We measured the changes of scattering intensity as a function of time during gelation and show the formation of a fractal structure.

When we mix our ester with an aqueous surfactant solution no precipitate is formed as observed in common template synthesis of mesoporous materials. Because of the water solubility of our silicate precursor it can be dissolved into the surfactant phase without phase separation. During hydrolysis of the precursor ethylene glycol is produced which does not affect the hydrophobic interaction of the surfactant.

It is shown by contrast variation that surfactant does not affect the fractal dimension of the final silica gel. Measurements after gelation demonstrate the unchanged presence of surfactant micelles.
Monomeric encapsulation of phthalocyanine‐dye molecules in the pores of Si‐MCM‐41 and Ti‐MCM‐41
Authors: Wark M. , Ortlam A. , Ganschow M. , Schulz‐Ekloff G. , Wöhrle D.
Published: July 2012

Titanium species and substituted or unsubstituted zinc phthalocyanine (ZnPc) complexes exhibiting negative, positive or no charges are incorporated in mesoporous MCM‐41 materials by (i) hydrothermal synthesis in the presence of hexadecyltrimethylammonium chloride as surfactant and (ii) impregnation of pre‐synthesized calcined Si‐MCM‐41.

The ordering of the hexagonal MCM‐41 structures is revealed from X‐ray diffractograms and nitrogen adsorption isotherms. The dispersion and the coordination of the Ti in the walls or in the pores is deduced from UV/Vis diffuse reflectance spectra (DR‐UV/Vis). The amount of Ti built into the walls of the MCM‐41 under maintenance of a perfect hexagonal structure is restricted to about 2 wt.‐%. In the pores up to 8 wt.‐% Ti can be fixed a silanol groups under molecular, i.e. non‐aggregated, dispersion.

The degree of dispersion of ZnPc is concluded from the analysis of the Q‐band structure in the DR‐UV/Vis spectra. Predominantly non‐aggregated ZnPcs in a monomeric state can be obtained, (i) if the ZnPC is incorporated in the micellar structure of the surfactant molecules by adding it to the synthesis gel of the MCM‐41 or (ii) if the ZnPc is adsorbed to Ti‐MCM‐41 with Ti species in high dispersion in the pores. A tight contact between the donor ZnPc and the acceptor titanium oxide, enables an electron transfer and a quenching of the fluorescence of the dye.
Spectroscopic investigations of the entrapment of hematoporphyrin IX in sol‐gel prepared silica and silica/titania gels and monoliths
Authors: Krüger J. M. , Breuer H. D.
Published: July 2012

By using the sol‐gel process, free base porphyrin doped silica and silica/titania, gels, monoliths, and glasses, with up to 20 wt.% titania, have been synthesised. The monoliths were characterised by BET isotherms, X‐Ray spectroscopy, and AFM spectroscopy. Absorption and fluorescence spectroscopic measurements indicate that, in Si and Si/Ti‐monoliths an equilibrium between the free base hematoporphyrin IX and its dicationic form exists. By additionally doping of pyrene as a donor dye, the energy transfer to hematoporphyrin IX as acceptor was investigated. Stem‐Volmer quenching of the fluorescence of pyrene was found in monoliths.
An EXAFS study on thiolcapped CdTe nanocrystals
Authors: Rockenberger Jörg , Tröger Larc , Rogach Andrey L. , Tischer Markus , Grundmann Marius , Weller Horst , Eychmüller Alexander
Published: July 2012

Temperature dependent EXAFS measurements have been carried out on 2‐mercaptoethanol‐stabilized CdTe nanocrystals. The technique allows to study the structural and dynamic properties of the CdTe core and the Cd‐SR (R = organic rest) shell separately. Based on the coordination numbers and the Cd/Te‐ratio determined by EXAFS, the formula [Cd54 Te32(SCH2CH2OH)52]8− is suggested. The underlying structure is a tetrahedral CdTe core (zincblende) partially coated by a Cd‐SR surface layer.
Fluorescence spectroscopical investigation of the gelation of sterical stabilised titanium dioxide sols
Authors: Krüger J. M. , Breuer H. D.
Published: July 2012

The gelation of TiO2‐sols, prepared by sol‐gel process, can be monitored by adding polyethylene glycol as polymer (sterical stabilisation). The forming of the inorganic TiO2 network was examined by using the microprobe technique. Pyrene was doped in TiO2‐sols and its characteristic fluorescence spectroscopic changes were investigated during the gelation. The vibrational fine structure of its emission spectrum changes and the ratio I3/I1 was determined and compared with homogenous solvents. By pulse fluorimetric measurements two different lifetimes of pyrene in TiO2‐sols were found.
X‐ray diffraction study of CCl4 crystallisation in vycor and silica gel mesopores
Authors: Schäfer Bernd , Langel Walter
Published: July 2012

The crystallisation of CCl4 in the mesopores of Vycor glass and silica gel has been studied by X‐ray powder diffraction. For the phase transitions from the liquid to the high temperature phase Ib and from Ib to the low temperature phase II undercooling is observed. At low temperatures the pore crystallites in Vycor have a coherence length of about 120 Å, which corresponds well to the pore chord distribution. Heating up from 67 K induces recrystallisation at about 180 K. The resulting crystallites of 500 Å in diameter show the phase transitions to the Ib phase and to the liquid at the bulk temperatures. We attribute this effect, which had not been seen before, to irreversible increase of the molecular order during cooling. The highly ordered phase attained at 67 K is thermodynamically unstable at 180 K and recrystallises. — In addition to Bragg reflections intense diffuse scattering is observed indicating amorphous zones with coherence lengths of the order of 11‐18 Å. We assign this to a surface layer whose structure is perturbed due to the interaction with the fractal Vycor surface.
Antiferroelectric gels
Authors: Strauss J. , Kitzerow H.‐S.
Published: July 2012

We have investigated the electro‐optic properties of a gel consisting of an antiferroelectric liquid crystalline (AFLC) mixture and an anisotropic polymer network, formed by photopolymerization of a mesogenic monomer. Like the pure AFLC mixture, the gel exhibits the well‐known tristable electro‐optical switching but with a decreased slope of the electro‐optic response curve, thus making gray‐scales available. In addition, the spontaneous polarization and the switching angle are reduced by the polymer network, whereas the switching times are independent of the polymer concentration. Applying a simple model, we found that the polymer network primarily changes the anchoring conditions of the liquid crystal.
Surface effects accompanying the Lα‐to‐L+α transition of the amphiphile C12E4 in water as studied by Neutron reflectivity
Authors: Steitz R. , Braun Chr. , Bowers J. , Lang P. , Findenegg G. H.
Published: July 2012

The interface of a concentrated solution of the amphiphile C12E4 in D2O against a hydrophobic‐coated silicon wafer has been studied near the congruent transition from the isotropic phase L1 to the lamellar phase Lα in a temperature range from 20 to 44°C by neutron reflectometry. The measurements reveal that the Lα phase — which is stable only in a narrow temperature range (20.6‐20.9°C at the chosen composition of 29 wt‐% C12E4 in D2O) ‐ couples strongly to the solid substrate, i.e. adjacent lamellae exhibit strong lateral correlation and are oriented parallel to the surface of the substrate. As the temperature is increased the sample transforms to a phase L+α which is stable from 20.9°C up to the highest experimental temperature. Unlike Lα, the Lα+ phase exhibits a broad Bragg peak in the reflectivity curve, indicating weak lateral correlation of adjacent lamellae. Furthermore, rocking scans reveal no significant coupling of the layers to the substrate surface. This finding is consistent with a disordered multilayered structure of the Lα+ phase suggested by other authors.
Molecular dynamics simulation of tracer diffusion of acetonitril in polyacrylamide hydrogels
Authors: Oldiges Christian , Tönsing Thorsten , Netz Paulo , Eimer Wolfgang
Published: July 2012

The diffusional motion of individual acetonitril molecules in polyacrylamide hydrogels has been investigated by molecular dynamics simulation. The mobility and the reorientation of the probe particles depend on their location within the polymer network. It can be separated between slow bound molecules and faster unbound molecules. To uncover the change in diffusion mechanism, we have followed the motion of individual probe molecules. Strong polymer‐solute interactions, which are dominated by hydrogen bonding, result in a significant retardation of the transport properties. In the solvent‐rich pores of the polymer matrix the acetonitril molecules can move freely as in pure water. A comparison of calculated diffusion coefficients reveals good agreement of the MD simulation results with experimental data.
Dynamics during thermoreversible gelation of the polysaccharide schizophyllan
Authors: Richtering Walter , Fuchs Tania , Burchard Walther
Published: July 2012

The β‐1.3/1.6 glucan schizophyllan is a fungal polysaccharid that is known to suppress tumor growth. Addition of sorbitol to aqueous solutions of schizophyllan led to a thermoreversible formation of optically transparent gels. The gelation process was followed by low amplitude oscillatory shear as well as by static and dynamic light scattering. Power law behavior of storage modulus G′(ω) and loss modulus G″(ω) was found at the gel temperature with an exponent n = 0.5. However, no power law was found for the time correlation functions as measured by dynamic light scattering. Two separated relaxation modes were found above and below the gel transition. The slow mode diverged below the gel temperature indicating a second critical point related to heterogeneities in the gel.
Birefringence and rubber‐elastic properties of crosslinked polymers in uniaxial deformation
Authors: Rennar Nikolaus
Published: July 2012

Measurements of birefringence and stress on well characterized endlinked PDMS, randomly crosslinked NR/IR elastomers, and polyether networks are reported in both uniaxial extension and compression. The experimental results are compared with predictions from modern theoretical concepts.

The reduced birefringence and the reduced stress are found to be dependent on the inverse deformation ratio 1/λ with a slight increase of both properties when going from extension to compression. Nevertheless, birefringence and stress seem to have the same dependence on extension respectively compression resulting in a stress‐optical coefficient (SOC) independent of the type and the amount of uniaxial deformation in the range 1.5>λ>0.7 according to the classical Kuhn‐Grün theory. Furthermore, the stress‐optical coefficients of endlinked PDMS and randomly crosslinked NR/IR networks in the unswollen state are constant over a wide range of crosslink densities and junction functionalities.

A detailed analysis of the birefringence data and the mechanical properties completed by the results of swelling tests indicates a considerable contribution of topological interactions (trapped entanglements) in a certain range of crosslink densities. This contribution seems to depend on the actual conditions of the network formation. The consistency of the above conclusions is supported by transversal 1H‐NMR relaxation experiments on the crosslinked samples.
Defined photo‐crosslinking and viscometric data I: Crosslinking via phenylindene and stilbazolium chromophors
Authors: Schinner Robert , Wolff Thomas , Kuckling Dirk
Published: July 2012

The photochemical formation of crosslinks between polymer chains leading to networks was studied in chloroform solution of polystyrene and in aqueous solution of poly‐N‐isopropylacrylamide. The former polymer was substituted with phenylindene, the latter with stilbazolium moieties. Both of which are chromophors crosslinkable via photodimerization. Depending on polymer concentration and chromophor content the polystyrene system in chloroform formed networks upon irradiation as revealed by increased viscosity and by the appearance of viscoelasticity. Up to three stress relaxation processes were indicated by rheological analysis of relaxation curves in viscoelastic solutions. In contrast, the poly‐N‐isopropylacrylamide system showed Newtonian flow throughout with moderate viscosity increase upon irradiation. This indicated that links were formed within separate polymer coils only.
Kinetic studies in liquid and gelated water/triblock copolymers mixtures
Authors: Knoll H. , Gille K.
Published: July 2012

Rate constants of the thermal cis‐trans isomerization of an azo dye in triblock copolymer (PEO‐PPO‐PEO)/water mixtures were determined by means of conventional flash photolysis. The rate constants change characteristically on micelle formation upon increasing the temperature. Moreover they indicate that the microenvironment of the dye molecules in the water/PEO interface layers of concentrated micellar solutions does not change significantly on gelation.
Electronic structures and nature of host excitation in borates
Authors: Mishra K. C. , Deboer B. G. , Schmidt P. C. , Osterloh I. , Stephan M. , Eyert V. , Johnson K. H.
Published: July 2012

We report the electronic structures of three large band gap borates β‐BaB2O4, YBO3 and LuBO3, and corresponding binary oxides BaO, Y2O3, Lu2O3 and B2O3. The main objective of this investigation is to explore how the electronic structures of complex oxides relates to their binary oxides, and how tightly bound anionic groups lead to large gap oxides. The calculated electronic structures lead to good agreement between observed optical gap and structure of the valence band for these oxides. While the borates lead to large gap materials, the excitations across the band gap do not always involve bonding and antibonding states of borate groups that are common to all the ternary oxides considered in this work. Although the top of the valence band is characterized by hybridized O 2p‐ and B 2p‐like states, the bottom of the conduction band can be due to metallic states. The presence of such states near the bottom of the conduction band was speculated earlier from the excitation properties of YBO3. We have also explored the possibility of designing a multi‐photon phosphor through core valence luminescence from a ternary oxide of Ba.
Viscous fingering at the liquid/liquid interface between two coexisting phases of mixtures with a miscibility gap
Authors: Wolf H. , Woermann D.
Published: July 2012

The influence of the viscosity contrast factor A [( = η“‐η′)/(η“+η), η, shear viscosity: (′)(”), indices of the coexisting phases; η“>η′]on the formation of viscous fingers at a mechanically unstable liquid/liquid interface of mixtures with a miscibility gap in a narrow rectangular glass cell (closed Hele‐Shaw cell) is studied. The systems used for the experiments are: (a) 2‐butoxyethanol (C4E1)/water mixtures of critical composition. They are studied in the vicinity of the lower critical point at temperatures above the critical temperature [1.05 < (η”η') < 2.0, corresponding to 0.05<A<0.4]. A is varied by changing the temperature of the mixture; (b) poly(ethylene glycol) (PEG)/dextran (D)/water mixtures at different compositions in the vicinity of the plait point at constant temperature [10<(η“/η')<40, corresponding to 0.762<A<0.950]. The liquid/liquid interfacial tension of both systems is small (σ<0.1 mN m−1). The experimental results are analysed in terms of theoretical work of Tryggvason and Aref (J. Fluid. Mech. 177, 207 (1985)). The viscous fingering process is treated as a two‐dimensional viscous flow. For small values of A (<0.12; system (C4El1/water) the growth rates of the viscous fingers in the upward and downward direction have about the same value and the fingers have a similar shape. At larger values of A (>0.3) the fingers formed by the phase with the higher viscosity advance faster into the phase with the lower viscosity than the fingers advancing in the opposite direction. This effect is pronounced in the system PEG/D/water for which A has large values (A>0.75). In this system the viscous fingers formed by the phase with the higher viscosity are long and narrow whereas that formed by the low viscosity phase are short and broad. The temperature dependence of the mean distance  between viscous fingers of the system C4E1/water advancing in opposite directions approaches the theoretically expected dependence at temperature differences (Tp‐Tc)>l K corresponding to a ratio (λmax/b) > 3 (λmax, wave length of fasted growing interfacial instability; b, width of the glass cell). The experiments show that the preferential wetting of the glass walls of the Hele‐Shaw cell by one of the coexisting liquid phases leads to a three‐dimensional shape of the viscous fingers.
Soot formation in the pyrolysis of halogenated hydrocarbons. Part I, binary mixtures of carbon tetrachloride with hydrogen and iron pentacarbonyl
Authors: Starikovsky A. Yu. , Thienel Th. , Wagner H. Gg. , Zaslonko Is.
Published: July 2012

Measurements on carbon particle growth during CCl4 thermal decomposition were carried out behind both incident and reflected shock waves. Three kind of mixture compositions have been investigated: 4000 ppm CCl4 in argon; 200 to 4000 ppm CCl4 and 200 to 8000 ppm Fe(CO)5 in argon; 4000 ppm CCl4 and 4000 ppm hydrogen in argon. The temperature range 1200<T/K<3200, pressure around 25 bar. Kinetics of the particle growth was detected via the attenuation of the laser beam (He‐Ne laser, 632.8 nm).

The low temperature boundary for soot particles detection and magnitude of soot yield in CCl4 pyrolysis is the same as that for most of the hydrocarbons studied. The temperature change during CCl4 pyrolysis is an important factor for its kinetic interpretation. The first order rate constants of soot growth kt/[C]are higher than those for all hydrocarbons, including benzene under comparable conditions. At T<2200 K the induction times tindare close to those for hydrocarbons with respect to both, absolute values and activation energy. In the middle temperature range studied, 2200<T/K<2500, an “induction‐less behaviour” of soot growth was observed; tind at T2500 K show a negative activation energy. Hydrogen additives significantly act on soot formation characteristics depending on H/Cl‐ratio.

Chemical reaction in mixtures CCl4/Fe(CO)5 was observed even at relatively low temperatures behind incident shock waves. However, iron additives only slightly change the soot yield as compared to CCl4 pyrolysis. A qualitative interpretation of experimental findings observed is suggested based on the consideration of the hierarchy of characteristic times in reacting systems followed by the growth of soot particles.
Direct investigations of reactions of 2‐butoxy radicals using laser pulse initiated oxidation: Reaction with O2 and unimolecular decomposition at 293 K and 50 mbar
Authors: Hein H. , Hoffmann A. , Zellner R.
Published: July 2012

Reactions of 2‐butoxy radicals have been investigated using time‐resolved measurements of NO2 and OH concentration profiles in the flash initiated oxidation of 2‐bromobutane and subsequent numerical simulation. 2‐butoxy radicals were produced selectively by the excimer‐laser photolysis of 2‐bromobutane at 193 or 248 nm followed by the reaction of 2‐butyl radicals with O2 and NO. Whereas NO2 was detected by cw‐LIF, detection of OH was achieved by laser long‐path absorption at 308 nm. All experiments were performed at 293 K and a total pressure of 50 mbar. The rate coefficients of the O2 reaction (kO2) and of unimolecular decomposition (kdecomp) have been varied, using the FACSIMILE code, until best fits were obtained. The following rate coefficients were derived: kO2 = (6.5±2) × 10−15 cm3‐molecule−1·s−1 and kdecomp = (3.5±2) × 10−3 s−1.
Nuclear spin state relaxation of formaldehyde in mixtures with inert gases
Authors: Peters G. , Schramm B.
Published: July 2012

Measurements of the rate constant of the ortho‐para conversion of monomeric gaseous formaldehyde H2CO in mixtures with He, Ar, H2, N2, CO, O2, CH3F and SF6 are described. Separation of the nuclear spin isomers of formaldehyde was obtained by selective UV laser photolysis of ortho‐formaldehyde in the natural ortho‐para mixture. Inert gas pressure was varied up to atmospheric pressure, formaldehyde pressure was 2.8 mbar in all experiments. At low pressures a linear increase of the rate constant with the inert gas pressure was found in all gases. With the noble gases, this increase was very small. In mixture with H2, N2, O2 and SF6 the rate constant rises up to a maximum and then shows a steep decrease as a function of the inert gas pressure. With the noble gases, CO and CH3F only the increase of the rate constant with pressure could be measured. The results are compared to the theory of Curl et al. [37]for the pressure dependence of the nuclear spin state relaxation of formaldehyde.
Sample size determination in clinical trials with multiple co‐primary endpoints including mixed continuous and binary variables
Authors: Sozu Takashi , Sugimoto Tomoyuki , Hamasaki Toshimitsu
Published: July 2012

In the field of pharmaceutical drug development, there have been extensive discussions on the establishment of statistically significant results that demonstrate the efficacy of a new treatment with multiple co‐primary endpoints. When designing a clinical trial with such multiple co‐primary endpoints, it is critical to determine the appropriate sample size for indicating the statistical significance of all the co‐primary endpoints with preserving the desired overall power because the type II error rate increases with the number of co‐primary endpoints. We consider overall power functions and sample size determinations with multiple co‐primary endpoints that consist of mixed continuous and binary variables, and provide numerical examples to illustrate the behavior of the overall power functions and sample sizes. In formulating the problem, we assume that response variables follow a multivariate normal distribution, where binary variables are observed in a dichotomized normal distribution with a certain point of dichotomy. Numerical examples show that the sample size decreases as the correlation increases when the individual powers of each endpoint are approximately and mutually equal.
Biocatalytic conversion of lignocellulose to platform chemicals
Authors: Jäger Gernot , Büchs Jochen
Published: July 2012

Naturally occurring lignocellulose can be used as a renewable resource for the sustainable production of platform chemicals that can in turn be converted to valuable fine chemicals, polymers, and fuels. The biocatalytic conversion of lignocellulose is a very promising approach due to its high selectivity, mild conditions, and low exergy loss. However, such biocatalytic processes are still seldom applied at the industrial scale since the single conversion steps (pretreatment, hydrolysis, and fermentation) may exhibit low conversion rates, low efficiencies, or high costs. The biocatalytic conversion of lignocellulose to platform chemicals is reviewed in this work. Structures and production rates of lignocellulose are described, and platform chemicals that may be produced from lignocellulose are summarized. Biocatalytic conversion of lignocellulose is distinguished from conventional non‐selective approaches. All essential conversion steps used in biocatalytic approaches (pretreatment, hydrolysis, and fermentation) are reviewed in detail. Finally, potential interactions between these conversion steps are highlighted and the advantages as well as disadvantages of integrated process configurations are elucidated. In conclusion, a comprehensive understanding of the biocatalytic conversion of lignocellulose is provided in this review.
Biomimetic soluble collagen purified from bones
Authors: Ferreira Ana Marina , Gentile Piergiorgio , Sartori Susanna , Pagliano Cristina , Cabrele Chiara , Chiono Valeria , Ciardelli Gianluca
Published: July 2012

Type I collagen has been extensively exploited as a biomaterial for biomedical applications and drug delivery; however, small molecular alterations occurring during the isolation procedure and its interaction with residual bone extracellular matrix molecules or proteins might affect the overall material biocompatibility and performance. The aim of the current work is to study the potential alterations in collagen properties and organization associated with the absence of proteoglycans, which mimic pathological conditions associated with age‐related diseases. A new approach for evaluating the effect of proteoglycans on the properties of isolated type I collagen from the bone matrix is described. Additional treatment with guanidine hydrochloride was introduced to remove residual proteoglycans from the collagen matrix. The properties of the isolated collagen with/without guanidine hydrochloride treatment were investigated and compared with a commercial rabbit collagen as control. We demonstrate that the absence of proteoglycans in the isolated type I collagen affects its thermal properties, the extraction into its native structure, and its ability to hydrate and self‐assemble into fibers. The fine control and tuning of all these features, linked to the absence of non‐collagenous proteins as proteoglycans, offer the possibility of designing new strategies and biomaterials with advanced biomimetic properties aimed at regenerating bone tissue in the case of fragility and/or defects.
The future of the protein data bank
Authors: Berman Helen M. , Kleywegt Gerard J. , Nakamura Haruki , Markley John L.
Published: July 2012

The Worldwide Protein Data Bank (wwPDB) is the international collaboration that manages the deposition, processing and distribution of the PDB archive. The wwPDB's mission is to maintain a single archive of macromolecular structural data that are freely and publicly available to the global community. Its members [RCSB PDB (USA), PDBe (Europe), PDBj (Japan), and BMRB (USA)] host data‐deposition sites and mirror the PDB ftp archive. To support future developments in structural biology, the wwPDB partners are addressing organizational, scientific, and technical challenges. © 2012 Wiley Periodicals, Inc. Biopolymers 99: 218–222, 2013.
Modulation of cell attachment and collagen production of anterior cruciate ligament cells via submicron grooves/ridges structures with different cell affinity
Authors: Wang Peng‐Yuan , Wu Tsung‐Han , Chao Pen‐Hsiu Grace , Kuo Wei‐Hsuan , Wang Meng‐Jiy , Hsu Cheng‐Che , Tsai Wei‐Bor
Published: July 2012

This study aimed to investigate the effects of submicron‐grooved topography and surface cell affinity on the attachment, proliferation and collagen synthesis of anterior cruciate ligament (ACL) cells. Two grooved polystyrene (PS) surfaces (equal groove/ridge width of 800 nm) with a groove depth of 100 or 700 nm were fabricated and modified by oxygen plasma treatment, dopamine deposition and conjugation of RGD‐containing peptides to enhance cell affinity. The elongation and alignment of ACL cells was enhanced by grooved structures with increasing groove depths regardless of surface chemistry. On the other hand, cell spreading and proliferation mainly depended on surface chemistry, in accordance with surface cell affinity: O2 plasma < dopamine deposition < RGD conjugation. The synthesis of type I collagen was the highest by the ACL cells cultured on the 700 nm grooved surface conjugated with RGD peptides, indicating that both surface grooved topography and chemistry play a role in modulating collagen production of ACL cells. Furthermore, the type I collagen deposited on the 700 nm PS surface was aligned with grooves/ridges. Our results indicated that both ligand presentation and cell alignment are important in the physiological activities of ACL fibroblasts. Such information is critical for design of biomaterials for ACL tissue engineering. Biotechnol. Bioeng. 2013; 110: 327–337. © 2012 Wiley Periodicals, Inc.
Simultaneous clostridial fermentation, lipase‐catalyzed esterification, and ester extraction to enrich diesel with butyl butyrate
Authors: van den Berg Corjan , Heeres Arjan S. , van der Wielen Luuk A. M. , Straathof Adrie J. J.
Published: July 2012

The recovery of 1‐butanol from fermentation broth is energy‐intensive since typical concentrations in fermentation broth are below 20 g L−1. To prevent butanol inhibition and high downstream processing costs, we aimed at producing butyl esters instead of 1‐butanol. It is shown that it is possible to perform simultaneously clostridial fermentation, esterification of the formed butanol to butyl butyrate, and extraction of this ester by hexadecane. The very high partition coefficient of butyl butyrate pulls the esterification towards the product side even at fermentation pH and relatively low butanol concentrations. The hexadecane extractant is a model diesel compound and is nontoxic to the cells. If butyl butyrate enriched diesel can directly be used as car fuel, no product recovery is required. A proof‐of‐principle experiment for the one‐pot bio‐ester production from glucose led to 5 g L−1 butyl butyrate in the hexadecane phase. The principle may be extended to a wide range of esters, especially to longer chain ones. Biotechnol. Bioeng. 2013; 110: 137–142. © 2012 Wiley Periodicals, Inc.
Functional heterogeneity and heritability in CHO cell populations
Authors: Davies Sarah L. , Lovelady Clare S. , Grainger Rhian K. , Racher Andrew J. , Young Robert J. , James David C.
Published: July 2012

In this study, we address the hypothesis that it is possible to exploit genetic/functional variation in parental Chinese hamster ovary (CHO) cell populations to isolate clonal derivatives that exhibit superior, heritable attributes for biomanufacturing—new parental cell lines which are inherently more “fit for purpose.” One‐hundred and ninety‐nine CHOK1SV clones were isolated from a donor CHOK1SV parental population by limiting dilution cloning and microplate image analysis, followed by primary analysis of variation in cell‐specific proliferation rate during extended deep‐well microplate suspension culture of individual clones to accelerate genetic drift in isolated cultures. A subset of 100 clones were comparatively evaluated for transient production of a recombinant monoclonal antibody (Mab) and green fluorescent protein following transfection of a plasmid vector encoding both genes. The heritability of both cell‐specific proliferation rate and Mab production was further assessed using a subset of 23 clones varying in functional capability that were subjected to cell culture regimes involving both cryopreservation and extended sub‐culture. These data showed that whilst differences in transient Mab production capability were not heritable per se, clones exhibiting heritable variation in specific proliferation rate, endocytotic transfectability and N‐glycan processing were identified. Finally, for clonal populations most “evolved” by extended sub‐culture in vitro we investigated the relationship between cellular protein biomass content, specific proliferation rate and cell surface N‐glycosylation. Rapid‐specific proliferation rate was inversely correlated to CHO cell size and protein content, and positively correlated to cell surface glycan content, although substantial clone‐specific variation in ability to accumulate cell biomass was evident. Taken together, our data reveal the dynamic nature of the CHO cell functional genome and the potential to evolve and isolate CHO cell variants with improved functional properties in vitro. Biotechnol. Bioeng. 2013; 110: 260–274. © 2012 Wiley Periodicals, Inc.
Jurors' Use of Standards of Proof in Decisions about Punitive Damages
Authors: Woody William Douglas , Greene Edie
Published: July 2012

Standards of proof define the degree to which jurors must be satisfied that a fact is true, and plaintiffs in civil lawsuits assume the burden of proving their claims to the requisite standard of proof. Three standards—preponderance of evidence, clear and convincing evidence, and beyond a reasonable doubt—are used by different jurisdictions in trials involving liability for punitive damages. We investigated whether individual mock jurors apply these standards appropriately by instructing them to read two personal injury trial summaries and to use one of three standards in either qualitative or quantitative format when deciding punitive liability. Results showed that jurors tended not to incorporate the standard into their judgments: defendants were just as likely to be found liable when the plaintiff's burden was high (“beyond a reasonable doubt”) as when the burden was low (“preponderance of evidence”). The format of the instruction also had a negligible effect. We suggest that nonuse of the standard of proof is related to jurors' preferences for less effortful or experiential processing in situations involving complicated or ambiguous material. Copyright © 2012 John Wiley & Sons, Ltd.
Networked multiplayer cooperative interaction using decoupled motion control method in a shared virtual environment with haptic, visual and movement feedback
Authors: Liu Guanyang , Lu Keke
Published: July 2012

This paper focuses on multiplayer cooperative interaction in a shared haptic environment based on a local area network. Decoupled motion control, which allows one user to manipulate a haptic interface to control only one‐dimensional movement of an avatar, is presented as a new type haptic‐based cooperation among multiple users. Users respectively move an avatar along one coordinate axis so that the motion of the avatar is the synthesis of movements along all axes. It is different from previous haptic cooperation where all users can apply forces on an avatar along any direction to move it, the motion of which completely depends on the resultant force. A novel concept of movement feedback is put forward where one user can sense other users’ hand motions through his or her own haptic interface. The concept can also be explained wherein one person who is required to move a virtual object along only one axis can also feel the motions of the virtual object along other axes. Movement feedback, which is a feeling of motion, differs from force feedback, such as gravity, collision force and resistance. A spring‐damper force model is proposed for the computation of motion feedback to implement movement transmission among users through haptic devices. Experimental results validate that movement feedback is beneficial for performance enhancement of such kind of haptic‐based cooperation, and the effect of movement feedback in performance improvement is also evaluated by all subjects.Copyright © 2012 John Wiley & Sons, Ltd.
Effect of Massachusetts health insurance reform on mammography use and breast cancer stage at diagnosis
Authors: Keating Nancy L. , Kouri Elena M. , He Yulei , West Dee W. , Winer Eric P.
Published: July 2012

BACKGROUND:

Massachusetts law requires all residents to maintain a minimum level of health insurance, and rates of uninsurance in that state decreased from 6.4% in 2006 to 1.9% in 2010. The authors of this report assessed whether health insurance expansion was associated with use of mammography and earlier stage at breast cancer diagnosis.

METHODS:

By using a prereform/postreform design with a concurrent control (California), mammography rates in the last year were assessed using the Behavioral Risk Factor Surveillance System survey and the diagnosis of stage I (vs II/III/IV) breast cancers based on cancer registry data among women ages 41 to 64. Propensity score analyses were used to compare California women who were most similar to women in Massachusetts with Massachusetts women.

RESULTS:

Among propensity‐weighted cohorts, adjusted mammography rates in Massachusetts were 69.2% in 2006, 69.5% in 2008, and 69.0% in 2010. In California, the rates were 59% in 2006, 60.3% in 2008, and 56.2% in 2010 (P = .89 for interaction by state for 2010 vs 2006). Among propensity‐weighted cohorts, adjusted rates of diagnosis with stage I cancers were 52.2% in 2006, 53.5% in 2007, and 52.4% in 2008 in Massachusetts versus 46.4% in 2006, 46.3% in 2007, and 45.7% in 2008 in California (P = .58 for interaction by state for 2010 vs 2006).

CONCLUSIONS:

Health insurance reform in Massachusetts was not associated with increased rates of mammography or earlier stage at diagnosis compared with California, possibly because of insurance and mammography rates that already were high. Additional research is needed to assess the impact of insurance expansions in other populations, especially those with higher uninsurance rates. Cancer 2013. © 2012 American Cancer Society.