bluuebunny/crossref_metadata_2025_split huggingface dataset:
Opposite trends in thermodynamic compatibility between copolyamide and chitosan in their binary blend
Authors: Safronov Alexander P. , Suvorova Anna I. , Tyukova Irina S. , Smirnova Yelena A. 
Published: August 2007

AbstractGibbs energy, enthalpy, and entropy of mixing in binary blends of chitosan with ter‐copolyamide 6/66/610 at ambient conditions have been determined over the entire concentration range using thermodynamic cycle based on dissolution of individual polymers and their blends of different composition in a common solvent – formic acid. Experimental procedure included stepwise equilibrium vapor sorption of glacial formic acid on the cast films and isothermal microcalorimetry of dissolution of these films in liquid glacial formic acid at 25 °C. Formic acid appeared to be a very good solvent for individual polymers and their blends. Flory‐Huggins interaction parameter determined from sorption isotherms was negative and varied from −2.56 to −1.79 depending upon blend composition. The enthalpies of dissolution of individual polymers and their blends were strongly exothermic and varied from −200 to −40 Joule/g. Independent thermodynamic cycles for Gibbs free energy and enthalpy remarkably revealed similar trends in concentration dependence of different thermodynamic functions of mixing between chitosan and copolyamide. At high chitosan content, the binary blend is characterized by large and negative values of Gibbs free energy, enthalpy, and entropy of mixing that provide high polymer compatibility. On the contrary, at high copolyamide content the blends are incompatible and are characterized by positive values of enthalpy, entropy, and Gibbs free energy of mixing. Such complicated thermodynamic behavior is the result of the superposition of strong molecular interactions (H‐bonds) between polymers in the blend and isothermal fusion of copolyamide crystallites. Thermodynamic analysis correlates well with the data obtained by polarized microscopy. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2603–2613, 2007
Deformation and fracture behavior of high‐energy electron irradiated poly(vinylidene fluoride‐trifluorethylene) ferroelectric copolymer films under uniaxial tension
Authors: Fang F. , Yang W. , Zhang M. Z. , Wang Z. 
Published: August 2007

AbstractThe deformation and fracture behavior under uniaxial tension were characterized for high‐energy irradiated poly(vinylidene fluoride‐trifluorethylene) (P(VDF‐TrFE)) 68/32 mol % copolymer films. The results show that the stress–strain behavior of the irradiated copolymer films exhibits ductile polymeric behavior, with its fracture strain being more than five times of that of the nonirradiated ones but of much lower maximum strength. X‐ray diffraction (XRD) analysis and scanning electron microscope (SEM) observation are carried out to examine the microstructure and morphology changes caused by the uniaxial tension. It is demonstrated that the tensile mechanical field reintroduces the polar β‐phase that was previously lost through irradiation. It is suggested that the conformational change from the nonpolar phase to the polar β‐phase during the uniaxial tension, as well as the low crystallinity and loosely packed molecular chain structure, mainly contribute to the observed stress–strain behavior for the irradiated copolymer films. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2563–2567, 2007
Antitumor activity of Hypericum hookerianum against DLA induced tumor in mice and its possible mechanism of action
Authors: Dongre Santoshkumar H. , Badami Shrishailappa , Godavarthi Ashok 
Published: August 2007

AbstractA large number of plants belonging to the genus Hypericum and their phytoconstituents are known to possess potent anticancer nature. Earlier studies from our laboratories indicated a strong cytotoxic nature of the methanol extract of Hypericum hookerianum stem (MEHH). In the present study, the in vivo antitumor activity of MEHH against the Dalton's lymphoma ascitic (DLA) model was determined at 100 and 200 mg/kg body weight given orally for 10 days. The results indicate that administration of the extract not only increased the survival of animals with ascites tumor, decreased the body weight induced by the tumor burden and reduced the packed cell volume and viable tissue cell count, but also altered many hematological parameters changed during tumor progression indicating the potent antitumor nature of the extract. Hematological and biochemical analysis were carried out to prove the anticancer and antioxidant nature of the extract. Copyright © 2007 John Wiley & Sons, Ltd.
The Planck‐Benzinger thermal work function: Determining the thermal set point in interacting biological systems
Authors: Chun Paul W. 
Published: August 2007

AbstractOne of the more interesting discoveries in recent studies of biological thermodynamics concerns the way in which application of the Planck–Benzinger methodology allows one to evaluate how the thermal set point of a biological system is established and maintained on a molecular level. Macromolecular interactions will always exhibit a negative minimum value of the Gibbs free energy change at a well‐defined temperature, <TS>, which may be defined as the thermal set point. Each interacting biological system will have its own unique value of <TS> where the bound unavailable energy TΔS0 = 0. In the human body, that thermal set point is 37°C. At the thermal set point, the maximum work can be accomplished and the system is at its most stable. Each interacting biological system examined by the Chun method confirms the existence of a thermodynamic molecular switch wherein a change of sign in ΔCp0(T) leads to true negative minimum in the Gibbs free energy change of reaction, and hence a maximum in the related equilibrium constant, Keq. Application of the Planck–Benzinger methodology has demonstrated that there is a lower cutoff point, <Th>, where entropy is favorable but enthalpy is unfavorable, and an upper cutoff, <Tm>, above which enthalpy is favorable but entropy unfavorable. Only between these two limits, where ΔG0(T) = 0, is the net chemical driving force favorable for such biological processes as protein folding, protein–protein or protein–nucleic acid interaction and protein self‐assembly. In examining interacting biological systems, the thermal set point will vary from one organism to another, but TΔS0, the bound unavailable energy, will always be equal to zero. It is apparent from Chun's extensive studies of biological interactions that the origins of life in any chosen system are inevitably linked to a single, unique thermal set point. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Effect of sampling method on diatom composition for use in monitoring and assessing large river condition
Authors: Lane Charles R. , Flotemersch Joseph E. , Blocksom Karen A. , Decelles Susanna 
Published: August 2007

AbstractMultiple diatom sampling methods exist for the assessment of lotic systems but few comparisons of their application efficacies in monitoring have been conducted. In this study 60 sites were sampled on four large, non‐wadeable rivers in Ohio and Kentucky, USA, which varied in depth, flow rate, surrounding land use and hydrologic modification. Four algae sampling methods were tested: three methods U.S. Environmental Protection Agency (U.S. EPA) Environmental Monitoring and Assessment Program (EMAP), U.S. Geological Survey (USGS QUAL and USGS QUAN) collected algae from rocks, debris and sediment in the littoral zone along a 1–2 km reach, while one method (USGS PHYTO) consisted of three cross‐river phytoplankton grab samples collected from a boat. Physical and chemical data were also collected. Little difference in diatom assemblage composition was found among the EMAP, QUAL and QUAN methods. Although compositionally similar, the PHYTO method collected a substantial proportion of relatively unique diatoms compared to the littoral zone methods.Two disturbance gradients were calculated, one based on 1 km upstream land use within a 500 m buffer, and the other based on principal component analysis dimension reduction of measured water parameters (PCAWQ). Metrics, generally indicators of eutrophication, were calculated for each sampling method and correlated with the disturbance gradients. After Bonferroni corrections, the EMAP method had six metrics correlated with the PCAWQ, while the PHYTO and QUAL methods each had four correlated metrics. Two QUAN metrics were correlated with the PCAWQ. Few metrics were correlated with the land use measure of disturbance. While the EMAP method had the most correlated metrics, this method, along with QUAL and QUAN methods are time and labour intensive (>1 h), relative to the phytoplankton method (<20 min). Resource managers may desire to weigh the benefits of two additional metrics with the EMAP method versus the costs associated with increased sampling time and effort. Published in 2007 by John Wiley & Sons, Ltd.
Outcome of antenatally diagnosed abdominal wall defects
Authors: Fratelli N. , Papageorghiou A. T. , Bhide A. , Sharma A. , Okoye B. , Thilaganathan B. 
Published: August 2007

AbstractObjectiveTo examine the natural history and detailed outcome of antenatally diagnosed abdominal wall defects.MethodsThis was a retrospective review of the antenatal reports, pediatric surgery records and subsequent follow‐up information of all cases of omphalocele and gastroschisis diagnosed in a 10‐year period in our tertiary referral center.ResultsThere were 109 cases of abdominal wall defects, including omphalocele in 67 cases and gastroschisis in 42 cases. Of the 67 cases of omphalocele there were 26 (39%) with chromosomal abnormalities and 22 (33%) underwent termination of pregnancy, mainly for associated structural abnormalities. Of the ongoing 19 cases there were five (26%) in‐utero deaths, 12 (63%) survivors and two (11%) neonatal deaths, both associated with prematurity. Excluding chromosomal abnormalities, the survival rate in isolated omphalocele was 7/16 (44%) whilst it was 5/25 (20%) in those with associated abnormalities. Gastroschisis was isolated in 40 (95%) cases. Among these 40 isolated cases there were two (5%) terminations. Of the 38 ongoing cases, there were two (5%) in‐utero deaths, and 36 (95%) live births. Four of the 36 liveborn infants (11%) died in the postoperative period owing to complications of small bowel atresia.ConclusionsAlthough only 18% of infants with antenatally diagnosed omphalocele were alive in the neonatal period, postoperative morbidity was low. The majority (90%) of fetuses with antenatally diagnosed gastroschisis survived to delivery, but the mortality in affected newborns was 11%. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Alte Faustregeln für das Design optischer Schichtsysteme
Authors: Kaiser Norbert 
Published: August 2007

AbstractOptische Schichten dienen zum Einstellen der optischen Eigenschaften einer Oberfläche. Ihre Funktion beruht auf dem Interferenzeffekt und/oder den intrinsischen Eigenschaften der Schicht‐ und Substratmaterialien. Im Folgenden werden alte Faustregeln wiederholt, die grundlegend für das Design optischer Schichten sind.
Optimization of plastisol processes by dynamic mechanical analysis
Authors: Daniels Paul H. 
Published: August 2007

AbstractDynamic mechanical analysis (DMA) can be a particularly useful tool for studying PVC plastisol manufacturing processes. DMA temperature sweeps are uniquely able to characterize plastisol gelation and fusion behavior under low shear stress conditions that are similar to conditions found in many commercial plastisol processing operations. Dynamic mechanical analysis is also well‐suited for studying plastisol melt viscosities at low shear rates such as might be encountered in a flexible PVC foaming process or rotomolding process. Likewise, DMA rate sweeps or strain sweeps can give insights into self‐association and flow properties in a plastisol which ordinary viscometers cannot provide. J. VINYL ADDIT. TECHNOL., 13:151–154, 2007. © 2007 Society of Plastics Engineers
Use of nonpolar processing aids to improve the efficiencies of extruded polyolefins
Authors: Marshall Niall , Visser Gideon 
Published: August 2007

AbstractThe addition of nonpolar processing aids has been shown to widen the processing window for manufacturers of polyolefin film and other extruded products. Opportunities exist to run lines stably at faster speeds with power savings. The benefits of using a nonpolar processing aid in blown film are discussed. J. VINYL ADDIT. TECHNOL., 13:155–158, 2007. © 2007 Society of Plastics Engineers
Rapid method for determination of unsulfonated oils
Authors: Weeks L. E. , Haynes R. T. , Eccles E. J. 
Published: August 2007

AbstractA primary limitation to alkylbenzene sulfonation processes has been the lack of a rapid method to sense the quality of sulfonation. This is especially true for a process using sulfur trioxide where both the level of sulfonating agent and time are critical: too little reagent results in high oils; too much reagent degrades product color; and a delay in the process also degrades color. Although steam distillation of oils from the neutralized sulfonate can be conducted in about one and one‐half hours for commercial dodecylbenzene derivatives, far greater time is required for higher molecular weight homologs. Extraction of oils requires about one hour and more operator time than distillation.The use of ethylene glycol as the principal carrier solvent, along with a small amount of water, provides oil values within 10 min distillation time. It is also applicable to longer chain alkylbenzene. sulfonates besides those from dodecylbenzene. Subsequently, extracted oils are high, ca. 90%, in sulfone content. Glycol distilled oils plus subsequently extracted oils (sulfones) are slightly greater than oils obtained exclusively by extraction. It has been realized that some of the more volatile oils are lost during the usual extraction procedure.The glycol oils distillation method has been successfully used in plants for alkylbenzene sulfonic acid quality control.
The preparation and properties of some synthetic glycerides. I. Procedures to Minimize contaminants in intermediates and constituent fatty acids
Authors: Jackson J. E. , Lundberg W. O. 
Published: August 2007

AbstractThe preparation of 1‐monotritylglycerol and the debromination of tetrabromostearic acid have been modified to increase the purity of glycerides synthesized by procedures involving these two compounds. Solubility and melting point data showed that ditritylglycerol, formed as a by‐product in the reaction between trityl chloride and glycerol, is not readily separable from monotritylglycerol, and its presence is difficult to detect unless special melting point methods are used. To minimize formation of ditritylglycerol, large excesses of glycerol were used in the preparation of monotritylglycerol. In the preparation of linoleic acid from tetrabromostearic acid, formation oftrans double bonds was reduced to a minimum by increasing the amount of mineral acid used to promote the debromination with zinc dust.
Hydrogenation of linolenate. VIII. Effects of catalyst concentration and of temperature on rate, selectivity, andtrans formation
Authors: Johnston A. E. , ven Horst Helen M. , Cowan J. C. , Dutton H. J. 
Published: August 2007

AbstractThe effects of catalyst concentration and of temperature on linolenate selectivity,trans formation, and rate of hydrogenation have been studied for a commercial electrolytic nickel catalyst. Results obtained with an equimixture of linoleate and linolenate, following the procedure previously described, are presented as isometric drawings, which cover the experimentally practicable temperature ranges from 70舑230C and nickel concentration from 0.05舑10%. Whereas the rate of hydrogenation depends upon both temperature and catalyst concentration,trans formation is essentially a function of temperature while selectivity is little influenced by either parameter.
The analysis ofCis‐trans fatty acid isomers using gas‐liquid chromatography
Authors: Litchfield Carter , Reiser Raymond , Isbell A. F. 
Published: August 2007

AbstractThe geometric isomers of many unsaturated fatty acid methyl esters can be separated using high‐resolution gas‐liquid chromatography on polyester or Apiezon columns. Separations reported for the geometric isomers of monounsaturated, ricinoleic, linoleic, conjugated, and epoxy fatty acids are reviewed here. New data is presented on the resolution of linolenate geometric isomers on both polyester and Apiezon columns. The separation of methyl oleate and methyl elaidate on a polyester column has also been accomplished. Techniques for preparing and using the high‐resolution columns necessary for these separations are reviewed.
Interactions in the system: Clay‐detergent‐cellulose
Authors: Schott Hans 
Published: August 2007

AbstractThe McBain equation describing detergency was used to study the process cellulose·clay+detergent= cellulose·detergent+clay·detergent, by taking thoroughly purified cotton, montmorillonite swelling clay, and n−C12H25O (CH2CH2O)−14H as well as other nonionic and anionic detergents. The three binary equilibria which add up to this ternary system were also studied.X‐ray diffraction showed that monionic detergents sorbed by the clay were intercalated between adjacent, 9.5 Å thick lattice layers of clay with their chains parallel to these layers, in sheets one or two molecules thick. The process was accompanied by dehydration and proceeded down to low equilibrium detergent concentrations. The deflocculation of sodium montmorillonite suspensions by polyoxyethylated compounds was shown by an increase in turbidity and decreases in viscosity and sedimentation volume. Cellulose sorbed C12H25O (CH2CH2O)14H reversibly. Its uptake was considerably less than that of clay on a weight basis but was comparable on an area basis.Kaolinite and calcium montmorillonite picked up by cellulose from aqueous suspensions were gradually removed by washing with water, following first‐order kinetics.Of the sodium montmorillonite picked up, 0.13±0.01% could not be removed by washing with water. This level of tenaciously retained clay was independent of clay concentration, rate of stirring, and temperature. The ash of fabric treated with sodium montmorillonite was a shrunken replica of the fabric, preserving microscopic details faithfully. This and comparison of the specific surface areas of cotton and sodium montmorillonite indicate that cotton was completely coated with clay to an average depth of three to four lattice layers. The reason for this thickness is that the primary particles in sodium montmorillonite dispersions are packets of three to four lattice layers.Anionic and cationic detergents removed little or none of the 0.13% sodium montmorillonite. Polyoxyethylated and polyoxypropylated compounds removed part but always left behind at least 0.04%. This is the amount of clay required to cover the cellulose surface completely with a sheet of single, nonoverlapping lattice layers. However, when brought into contact in the presence of nonionic detergents, cellulose retained no sodium montmorillonite at all.
The chemistry of detergent perfumery
Authors: Steltenkamp Robert J. 
Published: August 2007

AbstractDetergents constitute a low‐price, bulk item, which consumes a large quantity of aromatic materials. Detergent perfumes must not only meet the normal requirements of odor and stability but also strict demands in low price and high availability.The perfumes used in detergents are normally a complex mixture consisting of synthetic materials produced from either petroleum or coal tar products, isolates of natural products or synthetics derived from isolates and natural products such as the essential oils.The synthetics and isolates which are commonly used in detergent perfumery are discussed with their methods of production. The essential oils that can meet the demands of price and availability are listed.
Surface activity of sodium salts ofalpha‐sulfo fatty esters. The oil/water interface
Authors: Subba Rao V. V. , Fix R. J. , Zettlemoyer A. C. 
Published: August 2007

AbstractAdsorption studies at the heptane/water and the benzene/water interfaces have been conducted for four α‐sulfo fatty esters: sodium hexyl α‐sulfopelargonate, sodium heptyl α‐sulfopelar‐gonate, sodium methyl α‐sulfomyristate, and sodium methyl α‐sulfopalmitate. The results were compared with those at the air/water (A/W) interface (3). Surfactant solutions with constant counter‐ion concentrations of 0.01 and 0.04 M Na+ were used. Interfacial tensions were measured by using a drop‐volume method and were found to be in the range 1 to 25 dynes/cm.The critical micelle concentration (CMC) values of, these esters were in the range 8.1 to 0.14 mM at the A/W interface (3); they were decreased by about 10% in the presence of heptane (7.2 to 0.11 mM) and by 30–40% in the presence of benzene (5.5 to 0.08 mM). This decrease in CMC was attributed to the water solubility of the hydrocarbon; the greater the solubility, the larger was the decrease in CMC.The co‐areas at the A/W interface were in the range 44 to 59 Å2/ for all the esters (3). At the heptane/water interface they were in the range 49 to 66 Å2/ and at the benzene/water interface in the range 59 to 75 Å2/, i.e., an increase of about 10% was obtained in the presence of heptane and about 30–40% in the presence of benzene. The surface films at the O/W interface were more expanded than at the A/W interface, as expected, owing to the lack of lateral cohesion between the hydrocarbon chains at the O/W interface.
Free radical addition of hydrogen sulfide and thiols to linseed oil and methyl oleate
Authors: Schwab A. W. , Gast L. E. , Cowan J. C. 
Published: August 2007

AbstractFree radical additions of hydrogen sulfide, ethanedithiol, and 1,6‐hexanedithiol have been made to methyl oleate and linseed oil with ultraviolet radiation. Reactions were carried out in dichloromethane at −70C and in benzene at 25C. With the dithiols, a new dibasic ester has been prepared from methyl oleate in which bridging is accomplished through a dithiol moiety. Hydrogen sulfide has been added to linseed oil in suitable solvents at both −70C and 25C. It appears that zero‐order kinetics control the additions at both temperatures. Infrared data show a linear relationship between mercapto absorption and the amount of sulfur incorporated. Nuclear magnetic resonance (NMR) spectra demonstrate a decrease in olefinic protons with an increase in sulfur content. Fair agreement on the extent of reaction exists between data from NMR, sulfur content, and infrared analyses. Hydrogen sulfide‐treated linseed oil films air‐dry slowly at room temperature; at 250C for 1 hr under a CO2 atmosphere these oils cure to brown films with Sward Rocker values of 24 to 32 and pencil hardness values of five to greater than six. Pencil hardness and alkali resistance increased with sulfur content. The film from the 4.2% sulfur sample resisted alkali at room temperature for 24 hr.
Cottonseed oil oxidation catalyzed by amino acids and albumin in aqueous and nonaqueous media
Authors: Farag R. S. , Osman S. A. , Hallabo S. A. S. , Nasr A. A. 
Published: August 2007

AbstractOxidation of refined cottonseed oils catalyzed by various α‐amino acids and albumin has been studied in aqueous and nonaqueous media, Cysteine, phenylalanine, and albumin possessed prooxidant effect in cottonseed oil in aqueous and nonaqueous media. Serine exhibited prooxidant activity in aqueous media and minor antioxidant activity in nonaqueous media. Effectiveness of the amino acids on cotton‐seed oil oxidation was in the following descending order in both aqueous and nonaqueous media: cysteine > phenylalanine > serine. The prooxidant effect in aqueous media might be due to the predominant presence of the protonated amino nitrogen, whereas amino acid‐metal complex might be responsible for the prooxidant effect in nonaqueous media.