bluuebunny/crossref_metadata_2025_split huggingface dataset:
Theoretical studies on electron delocalization in diaminoguanidine
Authors: Bharatam Prasad V. , Iqbal Pansy 
Published: December 2005

AbstractAb initioMO and density functional methods have been employed to understand the electronic structure and second‐order delocalizations in diaminoguanidine. The potential energy surfaces of the three different positional isomers of diaminoguanidine (DAG1, DAG2, and DAG3) have been studied in detail, which suggest greater stability for DAG1 over the other isomers. Natural Population Analysis (NPA) has been employed to understand the primary and the secondary electron delocalizations in diaminoguanidine. The absolute proton affinity of diaminoguanidine is greater than both guanidine as well as aminoguanidine due to the extra stability from the intramolecular interactions in protonated diaminoguanidine. The increase in the electron delocalization upon protonation in diaminoguanidine is similar to that of guanidine and aminoguanidine. © 2005 Wiley Periodicals, Inc. J Comput Chem 27: 334–343, 2006
Superlinear scaling in master‐slave quantum chemical calculations using in‐core storage of two‐electron integrals
Authors: Fossgård Eirik , Ruud Kenneth 
Published: December 2005

AbstractWe describe the implementation of a parallel, in‐core, integral‐direct Hartree–Fock and density functional theory code for the efficient calculation of Hartree–Fock wave functions and density functional theory. The algorithm is based on a parallel master‐slave algorithm, and the two‐electron integrals calculated by a slave are stored in available local memory. To ensure the greatest computational savings, the master node keeps track of all integral batches stored on the different slaves. The code can reuse undifferentiated two‐electron integrals both in the wave function optimization and in the evaluation of second‐, third‐, and fourth‐order molecular properties. Superlinear scaling is achieved in a series of test examples, with speedups of up to 55 achieved for calculations run on medium‐sized molecules on 16 processors with respect to the time used on a single processor. © 2005 Wiley Periodicals, Inc. J Comput Chem 27: 326–333, 2006
Gaseous reaction mechanism of C2F radical with water
Authors: Wang Jian , Ding Yi‐Hong , Wu Gong‐Bing , Sun Chia‐Chung 
Published: December 2005

AbstractThe kinetic properties of the carbon–fluorine radicals are little understood except those of CFn (n =1–3). In this article, a detailed mechanistic study was reported on the gas‐phase reaction between the simplest π‐bonded C2F radical and water as the first attempt to understand the chemical reactivity of the C2F radical. Various reaction channels are considered. The most kinetically competitive channel is the quasi‐direct hydrogen‐abstraction route forming P5 HCCF + OH. At the CCSD(T)/6‐311+G(2d,2p)//B3LYP/6‐311G(d,p)+ZPVE, CCSD(T)/6‐311+G(3df,2p)//QCISD/6‐311G(d,p)+ZPVE and Gaussian‐3//B3LYP/6‐31G(d) levels, the overall H‐abstraction barriers (4.5, 4.7, and 4.2 kcal/mol) for the C2F + H2O reaction are comparable to the corresponding values (5.5, 3.7, and 5.7 kcal/mol) for the analogous C2H + H2O reaction. This suggests that C2F is a reactive radical like the extensively studied C2H, in contrast to the situation of the CF and CF2 radicals that have much lower reactivity than the corresponding hydrocarbon species. Thus, the C2F radical is expected to play an important role in the combustion processes of the carbon–fluorine chemistry. Furthermore, addition of a second H2O can catalyze the reaction with the H‐abstraction barrier significantly reduced to a marginally zero value (0.5 kcal/mol). This is also indicative of the potential relevance of the title reactions in the low‐temperature atmospheric chemistry. © 2005 Wiley Periodicals, Inc. J Comput Chem 27: 363–367, 2006
Common intersection designs
Authors: Lee Jooyoung , Stinson Douglas R. 
Published: December 2005

AbstractMotivated by an application to sensor networks, Lee and Stinson [6] defined a new type of set system termed a “common intersection design.” Briefly, a µ‐common intersection design is a 1‐design in which no pair of points occurs in more than one block, and in which any two disjoint blocks intersect at least µ blocks in common. In general, we want to maximize µ as a function of the other parmameters of the design. In this paper, we analyze combinatorial properties of common intersection designs. We determine necessary conditions for “optimal” common intersection designs and provide several existence results. Connections with other types of designs are pointed out. © 2005 Wiley Periodicals, Inc. J Combin Designs 14: 251–269, 2006
Use of volatile and non‐volatile amines to evaluate the freshness of anchovies stored in ice
Authors: Pons‐Sánchez‐Cascado Sofía , Veciana‐Nogués M Teresa , Bover‐Cid Sara , Mariné‐Font Abel , Vidal‐Carou M Carmen 
Published: December 2005

AbstractAmounts of volatile and biogenic amines, pH and microbial counts were monitored in Mediterranean anchovy (Engraulis encrasicholus) over 23 days of ice storage with the aim of examining their suitability as indicators of freshness. Counts of Enterobacteriaceae reached the maximum limits stipulated by Spanish regulations after 5 days of storage in ice, while those of mesophilic bacteria took 7 days. Levels of volatile amines hardly increased during ice storage. Amounts of biogenic amines did increase, though there were differences from one amine to the other. Cadaverine, the most abundant biogenic amine, showing the earliest increase, coinciding with the shelf‐life time as determined through Enterobacteriaceae counts. Amounts of histamine remained below the maximum levels established by both European Union and Food and Drug Administration regulations. Other biogenic amines were found at much higher levels than histamine. Results demonstrated the suitability of the biogenic amine index (as the sum of histamine + tyramine + putrescine + cadaverine) as a freshness indicator for anchovies stored in ice, with a limit of acceptability set at 15 mg kg−1. Copyright © 2005 Society of Chemical Industry
Effect of maltodextrin and emulsifiers on the viscosity of cake batter and on the quality of cakes
Authors: Lakshminarayan Sudha M , Rathinam Vetrimani , KrishnaRau Leelavathi 
Published: December 2005

AbstractThe effect of fat replacement by maltodextrin on cake batter viscosity and the quality of the resultant cakes was studied. The viscosity of batter was reduced significantly when fat was replaced with equal quantities of maltodextrin. Cakes prepared from this batter had low volume and firmer texture. Relatively better cakes were obtained when lower quantities of maltodextrin were used in the formulation. Viscosity of the above cake batter was relatively higher. A relationship between batter viscosity and cake volume was observed. Further improvement in cake volume could be achieved using emulsifiers. In the presence of glycerol monostearate little improvement in cake batter was observed, but the resultant cake volume was improved. However, sodium steroyl lactylate, which improved the batter viscosity, did not improve the cake volume or texture. Copyright © 2005 Society of Chemical Industry
The effects of genetic variation at r, rb and Tri loci in Pisum sativum L. on apparent ileal digestibility of amino acids in young broilers
Authors: Wiseman Julian , Al‐Marzooqi Waleed , Hedley Cliff , Wang Trevor L , Welham Tracey , Domoney Claire 
Published: December 2005

AbstractThe nutritional effect of genetic variation at r and rb loci was investigated by determining apparent and true amino acid digestibility of four near‐isogenic lines of pea (RRRbRb, RRrbrb, rrRbRb, rrrbrb) fed to young broilers in a metabolism study. The results demonstrated that the round‐seeded line (RRRbRb) generally had the lowest amino acid content with, for example, 2.5 g cystine kg−1 dry matter (DM) and 1.6 g methionine kg−1 DM, compared with contents in the three wrinkled‐seeded lines (rrRbRb, RRrbrb and rrrbrb). The double mutant line (rrrbrb) generally had the highest amino acid content, with 3.2 g cystine kg−1 DM and 2.3 g methionine kg−1 DM, and an elevated amino acid content compared with the single mutant lines (RRrbrb, rrRbRb). However, the round‐seeded line (RRRbRb) consistently had the highest coefficient of true (CTID), and apparent (CAID), ileal digestibility for all amino acids (e.g. 0.959 and 0.928 respectively for CTID and CAID for methionine) when compared with the three wrinkled lines RRrbrb, rrRbRb and rrrbrb (0.853, 0.877 and 0.866, respectively, for CTID, and 0.862, 0.882 and 0.874 for CAID). A second experiment examined the digestibility of amino acids in a pair of lines, HC8 and LC8, near‐isogenic except for the locus controlling the concentration of seed trypsin inhibitor (H, high; L, low). The results showed that the CAID and CTID obtained for all amino acids were consistently higher for LC8 than for HC8 (for methionine: 0.905 and 0.709 for CTID, respectively, for LC8 and HC8; 0.887 and 0.729, respectively, for CAID), indicating the very specific effects of quantitative variation in these proteins on nutritional value of peas for poultry. Copyright © 2005 Society of Chemical Industry
Functional properties of caseinate glycoconjugates prepared by controlled heating in the ‘dry’ state
Authors: Oliver Christine M , Melton Laurence D , Stanley Roger A 
Published: December 2005

AbstractGlucose, ribose, fructose, lactose, fructo‐oligosaccharide (inulin) and a mixture of inulin and fructose were conjugated with caseinate via the Maillard reaction using controlled heating and low water activity conditions in order to improve the functional properties of caseinate for food purposes. Conjugation with ribose and glucose increased the viscosity of caseinate 28‐fold over that of the unmodified caseinate control but also produced the most browning. Glycoconjugates of caseinate–fructose reacted at a substrate ratio of 1:0.2 w/w and 60 °C at 67% relative humidity for 48 h increased the viscosity of caseinate 24‐fold with less browning. At 80% relative humidity the reaction occurred so rapidly that, within 24 h gels containing darkly coloured particulate matter were produced. Incorporation of inulin at 1:1:0.2 w/w/w caseinate/inulin/fructose prevented formation of gels and produced glycoconjugates having 15‐fold the viscosity of unmodified caseinate with minimal browning. Copyright © 2005 Society of Chemical Industry
Organochlorine pesticide residues in poultry feed, chicken muscle and eggs at a poultry farm in Punjab, India
Authors: Aulakh Rabinder S , Gill Jatinder Paul S , Bedi Jasbir S , Sharma Jagdish K , Joia Balbir S , Ockerman Herbert W 
Published: December 2005

AbstractAnimals intended for human food may absorb pesticides from residues in their feed, water or during direct/indirect exposure in the course of pest control. The objective of the present investigation was to monitor organochlorine pesticide residues in poultry feed, chicken muscle and eggs at a selected poultry farm. The samples were Soxhlet extracted for 8 h in 200 mL hexane–acetone (1:1, v/v) mixture. The clean‐up of the samples was performed by silica gel column chromatography and analysis was done on a gas chromatograph equipped with an electron capture detector. The mean total hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT), endosulfan sulfate and heptachlor epoxide residues were 0.65, 0.91, 0.42 and 0.02 mg kg−1, respectively, in feed while respective values for chicken muscle were 0.11, 0.24, 0.10 and 0.07 mg kg−1. Higher residues were encountered in eggs as compared to muscle. None of the muscle samples exceeded maximum residue limits (MRL) for organochlorine pesticides, while all egg samples had values above the MRL for HCH and heptachlor epoxide and seven egg samples exceeded MRL for DDT residues. The results indicated that poultry feed could be one of the major sources of contamination for chicken and eggs. These residues are present despite complete ban on the use of technical HCH and DDT for agricultural purposes in India. Copyright © 2005 Society of Chemical Industry
Use of lasers and light‐based therapies for treatment of acne vulgaris
Authors: Mariwalla Kavita , Rohrer Thomas E. 
Published: December 2005

AbstractOver the last two decades, lasers and light‐based therapies have been developed to treat a wide variety of cutaneous maladies. Given the prevalence and number of patients who suffer from refractory acne, alternatives to existing care are constantly sought after. In this review, we discuss the evidence currently available to justify the use of laser and light‐based modalities and conclude that in combination therapy, such approaches provide a safe and effective treatment for acne vulgaris. Lasers Surg. Med. 37:333–342, 2005. © 2005 Wiley‐Liss, Inc.
Poly[(4‐hydroxybutyric acid)‐alt‐(glycolic acid)]: Synthesis by Thermal Polycondensation of Metal Salts of 4‐Chlorobutyric Acid Carboxymethyl Ester
Authors: Martínez‐Palau Meritxell , Franco Lourdes , Ramis Xavier , Puiggalí Jordi 
Published: December 2005

AbstractSummary: A new sequential copolyester consisting of glycolic acid and 4‐hydroxybutyric acid units was prepared by a thermal polycondensation method that uses the formation of metal chloride salts as a driving force. The polymerization conditions (time, temperature) were studied in order to obtain appropriate molecular weights and high yields. Thermal properties and thermal stability were also determined. The polymerization kinetics of sodium, potassium and cesium monomer derivatives were studied by differential scanning calorimetry and the results compared. Non‐isothermal data and an isoconversional procedure (free model) were applied to determine the Arrhenius parameters (activation energy and pre‐exponential factor). The kinetic model was selected according to both the Coats‐Redfern method and the evaluation of isokinetic parameters.DSC heating runs of sodium, potassium and cesium salts of 4‐chlorobutyric acid carboxymethyl ester after preheating at 100 °C.imageDSC heating runs of sodium, potassium and cesium salts of 4‐chlorobutyric acid carboxymethyl ester after preheating at 100 °C.
Multi‐Arm Star Polyglycerol‐block‐poly(tert‐butyl acrylate) and the Respective Multi‐Arm Poly(acrylic acid) Stars
Authors: Shen Zhong , Chen Yu , Barriau Emilie , Frey Holger 
Published: December 2005

AbstractSummary: Well‐defined multi‐arm star block copolymers, polyglycerol‐block‐poly(tert‐butyl acrylate) (PG‐b‐PtBA), with average arm‐numbers of 17, 27, 36, 66 and 90 arms, respectively, have been prepared by atom transfer radical polymerization (ATRP) of tBA in acetone, using a core‐first strategy. After hydrolysis with excess concentrated HCl in refluxing dioxane, full hydrolysis of the tert‐butyl ester groups was achieved, resulting in multi‐arm star polyelectrolytes, polyglycerol‐block‐poly(acrylic acid) (PG‐b‐PAA). The hyperbranched macroinitiators employed were prepared on the basis of hyperbranched polyglycerols via esterification with 2‐bromoisobutyryl bromide. Both CuBr/PMDETA and CuBr/Me6TREN catalyst systems have been employed for ATRP of tBA. CuBr/PMDETA was found to permit good control. Polydispersity indices for the new multi‐arm stars were mainly in the range of 1.22 to 1.4, and the absolute $\overline M _{\rm n}$ data were in agreement with the calculated values. Moreover, kinetic curves show a linear dependence of ln([M]0/[M]t) on time, confirming that the polymerizations are controlled.Relationship between arm numbers of the multi‐arm stars and maximum conversion achieved.imageRelationship between arm numbers of the multi‐arm stars and maximum conversion achieved.
Improving Impact Poly(propylene) Morphology and Production: Selective Poisoning of Catalyst Surface Sites and the Use of Antistatic Agents
Authors: Bouzid Djallel , McKenna Timothy F. L. 
Published: December 2005

AbstractSummary: Selective poisoning has been studied as a means of improving the morphology and rheological properties of high‐impact poly(propylene) copolymer particles. Two different methods of poisoning the catalyst surface in order to avoid the accumulation of ethylene‐propylene rubber (EPR) without influencing the reaction kinetics were tested: a slurry‐phase poisoning step using ethylene glycol dimethyl ether between the homopolymerisation and copolymerisation reaction steps; and direct poisoning via the use of a commercial antistatic agent during the gas‐phase copolymerisation reactor. It was observed that both methods eliminated the formation of rubber on the particle surface without noticeably influencing the kinetics. On the other hand, the use of the products directly in the gas‐phase reaction also contributed to the reduction of static electricity. It can be concluded from these experiments that industrial antistatic agents derive at least part of their effect from poisoning of the active sites on the surface of the catalyst. Furthermore, it appears that in the case of the catalyst used in this study, EPR does not appear to flow out of the growing particles. Most of the EPR found at the surface of the particles is formed close to it.SEM images of hiPP and GLYM001.imageSEM images of hiPP and GLYM001.
Synthesis and Characterization of Poly[((maleic anhydride)‐alt‐styrene)‐co‐(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid)]
Authors: Devrim Yilser G. , Rzaev Zakir M. O. , Pişkin Erhan 
Published: December 2005

AbstractSummary: Novel polyfunctional sulfone‐ and anhydride‐containing reactive terpolymers with different compositions have been synthesized by complex‐radical polymerization of the ternary MA‐St‐APMS acceptor‐donor‐acceptor monomer system. This method allows preparing terpolymers with a sufficiently high content of APMS which essentially increased polyelectrolyte, swelling, IEC and thermal stability of terpolymer films. The terpolymer structure‐composition‐properties (polyelectrolyte, thermal, swelling and cation exchange behavior) relationships were studied by FTIR and 1H{13C} NMR (DEPT‐135) spectroscopy, viscometry, DSC‐TGA methods, and by means of swelling and exchange capacity. The observed H‐bonding between sulfonic acid, amide and anhydride fragments played an important role in the formation of the physically crosslinked and self‐assembled architectures with controllable hydrophilic‐hydrophobic balance. These reactive terpolymers can be used as synthons for exchange membrane preparation and fuel cell applications.Physically crosslinked and self‐assembled macrocomplex.imagePhysically crosslinked and self‐assembled macrocomplex.
Pulsed Laser Polymerization of Alkyl Acrylates: Potential Effects of the Oxygen Presence and High Laser Power
Authors: Castignolles Patrice , Nikitin Anatoly N. , Couvreur Laurence , Mouraret Guillaume , Charleux Bernadette , Vairon Jean‐Pierre 
Published: December 2005

AbstractSummary: Unexpected difficulties are encountered in the determination of propagation rate coefficients (kp) in free radical polymerization of alkyl acrylates by pulsed laser polymerization (PLP), mainly due to intramolecular transfer to polymer.1 This article is focused on the role played by the high laser power in these difficulties and the possible reactions of mid‐chain radical with residual oxygen. Removing the oxygen by simple bubbling of nitrogen is sufficient to avoid alteration of the polymerization kinetics of acrylates by residual oxygen under PLP conditions. Moreover, no degradation of polymer (or solvent) has been detected after irradiation with the high laser power typically used in PLP experiments. However, it has been shown that this high laser power completely prevents from having a temporally and spatially homogeneous radical concentration in the PLP cell. A model is proposed here to simulate the pulsed laser polymerization taking initiator consumption and laser energy absorption into account. According to our simulation results, this non‐negligible initiator consumption and laser power absorption can indeed have a positive influence, i.e., it favors the obtainment of a bimodal molar mass distribution fulfilling the IUPAC consistency criteria. This observation may contradict the idea that PLP‐SEC is not suitable to determine accurate kp values for acrylates above 20–30 °C.Instantaneous MMDs formed after N pulses. Simulation taking initiator consumption and laser absorption into account.imageInstantaneous MMDs formed after N pulses. Simulation taking initiator consumption and laser absorption into account.
Polymer‐Polymer Interaction: Consistent Modeling in Terms of Chain Connectivity and Conformational Response
Authors: Wolf Bernhard A. 
Published: December 2005

AbstractSummary:An approach developed for the modeling of polymer solutions is extended to polymer blends. It accounts explicitly for the fact that the segments of a given macromolecule cannot spread out over the entire volume of the system (chain connectivity) and that the space a polymer molecule occupies may change after contact formation between the components of a mixture (conformational responseζ). The validity of the equation obtained for the Flory‐Huggins interaction parameter between polymers is tested by means of critical data published for the system PVME/PS. The measured phase diagrams can be modeled equally well by two limiting assumptions concerning the temperature dependence of the conformational response. However, using these two different sets of parameters to calculate the phase behavior for high molar masses of both polymers, leads to fundamental differences. One of them yields double critical points and predicts well defined critical compositions in the limit of infinite molar masses of both polymers, in contrast to the original Flory‐Huggins theory. The physical meaning of the different parameters is analyzed and the composition and temperature dependencies of the Flory‐Huggins interaction parameter resulting from the present modeling are compared with corresponding data reported in the literature.Double critical line (double critical concentrationφDCas a function ofmandn) calculated by means of Equation (12) and (13) using the system specific parameters given in row two of Table 2, and its projections into the different planes.imageDouble critical line (double critical concentrationφDCas a function ofmandn) calculated by means of Equation (12) and (13) using the system specific parameters given in row two of Table 2, and its projections into the different planes.
Isoconversional Analysis of Combined Melt and Glass Crystallization Data
Authors: Vyazovkin Sergey , Dranca Ion 
Published: December 2005

AbstractSummary: As proposed earlier (Macromol. Rapid Commun., 2004, 25, 733) the Kg and U* parameters of the Hoffman‐Lauritzen theory can be derived from isoconversional analysis of DSC data on melt crystallization. In this study, the analysis is extended to include both melt and glass crystallization data. The analysis of DSC data on non‐isothermal crystallization of poly(ethylene terephthalate) (PET) and poly(ethylene 2,6‐naphthalate) (PEN) demonstrates that for each of these polymers the combined melt and glass crystallization data can be described by single set of the Kg and U* values. The respective values for PET are 3.6 × 105 K2 and 7.5 kJ · mol−1 and for PEN 2.2 × 105 K2 and 6.6 kJ · mol−1. The use of combined data sets helps to improve the precision of computations.Experimental E on T data for melt (circles) and glass (squares) crystallization of PET.imageExperimental E on T data for melt (circles) and glass (squares) crystallization of PET.