bluuebunny/crossref_metadata_2025 huggingface dataset:
Ab initio studies on complexes formed by melamine and cyclotrione
Authors: Zhu Liangiang , Teng Qiwen , Wu Shi
Published: August 2007

Ab initio methods were used to study the binding energies of non-bonded complexes formed by melamine and cyclotrione, with the STO-3G, 3-21G and 6-31G (d) basis sets. The electronic spectra were computed using the INDO/CIS method, and the IR spectra, Raman and NMR spectra with the RHF/6-31G (d)method. It was demonstrated that the complexes could be formed because of the negative binding energies, which were changed with the change in the electronic properties of the monomers. A red-shift of the first absorptions in the electronic spectra and the vibrational frequencies of the N-H bonds in the IR and Raman spectra of the complexes, compared with those of the monomers, occurred; simultaneously, the 1Hand 13C chemical shifts were altered, due to the non-bonded interaction. .
Analysis of long-range correlation in sequences data of proteins
Authors: Isvoran Adriana , Unipan Laura , Craciun Dana , Morariu Vasile
Published: August 2007

The results presented here suggest the existence of correlations in the sequence data of proteins. 32 proteins, both globular and fibrous, both monomeric and polymeric, were analyzed. The primary structures of these proteins were treated as time series. Three spatial series of data for each sequence of a protein were generated from numerical correspondences between each amino acid and a physical property associated with it, i.e., its electric charge, its polar character and its dipole moment. For each series, the spectral coefficient, the scaling exponent and the Hurst coefficient were determined. The values obtained for these coefficients revealed non-randomness in the series of data. .
Surface characterization of polymers by inverse gas chromatography
Authors: Nastasovic Aleksandra , Onjia Antonije
Published: August 2007

An inverse gas chromatographic (IGC) study of the sorption properties of macroporous crosslinked poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate), PGME, and PGME modified with ethylene diamine, PGME-en, was presented. At infinite dilution, the thermodynamic parameters of adsorption, the dispersive components of the surface free energies, the acid/base constants and the interaction parameters for the initial and modified copolymer samples were investigated. The adsorption isotherms determined by IGC under conditions of finite surface coverage were used to estimate the surface area, the isosteric heat of adsorption and the adsorption energy distribution on the surface of the initial and modified copolymer samples. .
Synthesis and pharmacological evaluation of several N-(2-nitrophenyl) piperazine derivatives
Authors: Andric Deana , Tovilovic Gordana , Roglic Goran , Vaskovic Djurdjica , Soskic Vukic , Tomic Mirko , Kostic-Rajacic Sladjana
Published: August 2007

Six newly synthesized heterocyclic (2-nitrophenyl)piperazines, with a specific structure of the heteroaryl group, whichmimics the catechol moiety of dopamine (benzimidazoles and substituted benzimidazoles), were evaluated for their binding affinity to rat dopamine (DA), serotonin (5-HT) and _1 receptors. All compounds with a benzimidazole group had a 5-HT2A/D2 receptors binding ratio characteristic for atypical neuroleptics (>1, pK i values). Compound 7c, 4-bromo-6-{2-_4-(2-nitrophenyl)piperazin- 1-yl_ethyl}-1H-benzimidazole, expressed higher affinities for all receptor classes than clozapine. Also, it exhibited the best characteristic for atypical neuroleptics and presents a compound with the best profile for further in vivo investigations.
Antibacterial evaluation of some benzimidazole derivatives and their zinc(II) complexes
Authors: Podunavac-Kuzmanovic S.O. , Cvetkovic D.M.
Published: August 2007

Zinc(II) chloride was reacted with some 1-benzylbenzimidazole derivatives (L) to give complexes of the formula ZnL2Cl2. All the ligands and their zinc(II) complexes were evaluated for their in vitro antibacterial activity against Pseudomonas aeruginosa, Bacillus cereus, Staphylococcus aureus and Sarcina lutea. Themajority of the investigated compounds displayed in vitro antimicrobial activity against very persistent microorganisms. It was found that all the tested compounds were more active against gram-positive than gram-negative bacteria. The minimum inhibitory concentration (MIC) was determined for all ligands and their complexes. The effect of the structure of the ligands and complexes on the antimicrobial activity is discussed. The complexes were found to be more toxic than the ligands.
Oxidation of dibenzothiophene as a model substrate for the removal of organic sulphur from fossil fuels by iron(III) ions generated from pyrite by Acidithiobacillus ferrooxidans
Authors: Beskoski Vladimir , Matic Valerija , Milic Jelena , Godjevac Dejan , Mandic Boris , Vrvic Miroslav
Published: August 2007

Within this paper a new idea for the removal of organically bonded sulphur from fossil fuels is discussed. Dibenzothiophene (DBT) was used as a model compound of organicmolecules containing sulphur. This form of (bio)desulphurization was performed by an indirect mechanism in which iron(III) ions generated from pyrite by Acidithiobacillus ferrooxidans performed the abiotic oxidation. The obtained reaction products, dibenzothiopene sulfoxide and dibenzothiophene sulfone, are more soluble in water than the basic substrate and the obtained results confirmed the basic hypothesis and give the possibility of continuing the experiments related to application of this (bio)desulphurization process. .
A facile synthesis and the antimicrobial activity of some 4-aryltriazoles
Authors: Baluja Shipra , Chanda Sumitra , Chabhadiya Rajesh , Kachhadia Nikunj , Nair Rathish , Solanki Asif
Published: August 2007

Some 4-aryltriazoles were synthesized and tested for their antibacterial effects against Bacillus cereus, Pseudomonas testosteroni, Klebsiella pneumoniae Micrococcus flavus, and Citrobacter freundii. The 4-aryltriazoles were obtained by cyclization of the potassium salt of the appropriately substituted dithiocarbazinic acid with aromatic amines. The new synthesized compounds were characterized using infrared and 1H nuclear magnetic resonance spectroscopy and further supported by mass spectrometry. .
Structural effects of metallic chromium on its electrochemical behavior
Authors: Jegdic Bore , Drazic Dragutin , Popic Jovan , Radmilovic Velimir
Published: August 2007

Chromium dissolution in aqueous sulfuric acid solution of pH 1 was studied electrochemically on chromium electrodes with different crystallographic structures. A slow potentiodynamic method was used for the electrochemical measurements in deaerated solutions (purgedwith nitrogen),while the Cr(III) ions in the solution after the corrosion were determined by atomic absorption spectrometry. Three electrode materials with a very dominant crystallite orientation resembling single crystal structures (i.e., 111 and 110) confirmed by the electron backscattering diffraction (EBSD), were used in the experiments. The (111) structures were somewhat more active electrochemically (both anodic and cathodic) than the (110) structure. However, Cr electrochemically deposited in standard plating bath, assumed from literature data to has also the (111) structure, was more than 4 times active for anodic dissolution and, by the same number, less active for cathodic hydrogen evolution. The concentrations of Cr(III) ions determined in the solution after definite times of corrosion of all the materials showed almost two times larger dissolution rates than observed electrochemically by three different electrochemical methods (Wagner-Traud, Stern-Geary, electrochemical impedance spectroscopy). This is explained by the simultaneous occurrence of potential independent chemical dissolution of Cr, by a direct reaction of metallic Cr with H2O molecules, proposed a long time ago by Kolotyrkin and coworkers. .
Determination of lead in water resources by flame atomic absorption spectrometry after pre-concentration with ammonium pyrrolidinedithiocarbamate immobilized on surfactant-coated alumina
Authors: Talebi Morteza , Safigholi Homeyra
Published: August 2007

Arapid, simple, and sensitive procedure based on modified solid phase extraction was developed for the pre-concentration and determination of trace amount of lead in water resources. Lead was reacted with ammonium pyrrolidinedithiocarbamate (APDC) to make a complex. The complex was then collected in a column packed with surfactant-coated alumina. The parameters affecting the collection efficiency and desorption rate of the lead complexes from the column were investigated and optimized. The collection efficiency of the lead complex on the adsorbent was excellent under the optimized conditions. The results obtained from the recovery test showed the capability and reliability of the method for the analysis of trace amounts of lead. The proposed pre-concentration procedure made it possible to apply conventional flame atomic absorption spectrometry (FAAS) for the sensitive determination of trace amounts of lead in water resources. .
Bacterially generated Fe2(SO4)3 from pyrite, as a leaching agent for heavy metals from lignite ash
Authors: Jekic Jelena , Beskoski Vladimir , Gojgic-Cvijovic Gordana , Grbavcic Mirjana , Vrvic Miroslav
Published: August 2007

Investigations of heavy metals from lignite ash, which is a coal combustion by-product, have for years been very interesting from different aspects of environmental protection. In this study, the possibility of microbiological ash leaching, with a strong oxidation agent, bacterially generated Fe2(SO4)3 was investigated in order to minimize the concentration of toxic ash elements. Leaching experiment by the shake flask testing technique was performed during a period of 20 d at a temperature of 28?C. The results obtained show 5- to 22-fold (for Cd and Ni approx. 5, Zn approx. 6, Mn approx. 8, Cr approx. 13 and Cu approx. 22) higher metal leaching efficiency in the suspension with bacterially generated Fe2(SO4)3 than in the control suspension. .
Effect of an industrial chemical waste on the uptake of cations by green oat
Authors: Radulescu Hortensia , Taubert Lidia , Kiss Sándor , Princz Ecaterina , Stefanovits-Bányai Éva
Published: August 2007

Calcium carbonate, obtained as a waste in the industrial manufacture of magnesium carbonate and magnesium oxide from dolomites, can be applied in agriculture. The appreciable amounts of calcium and magnesium in this waste, together with impurities such as iron, zinc, manganese, chromium and copper compounds can be useful in soil amendment and plant nutrition. This paper presents preliminary results of the testing of several waste doses on soil, pursuing their effect on the uptake of cations by green oat (Avena sativa L.). The obtained results show an increase in the amount of calcium, magnesium, zinc and copper found in green oat plants, as well as a decrease of the content of iron and manganese with increasing waste dose. These results may be explained by lower absorptions of iron and manganese because of the antagonistic effect created by high amounts of calcium and magnesium, as well as by the presence of copper and zinc. .
Extraction of 137cs from Cetraria islandica lichen using acid solutions
Authors: Cuculovic Ana , Veselinovic Dragan , Miljanic Scepan
Published: August 2007

The extraction of 137Cs sorbed in samples of C. islandica using acid solutions was investigated. An equation describing the reduction of the 137Cs content in a dry lichen sample with the number of volumes of acid solutions used for successive extractions was used. The possibility of the existence of two different types of sorption of 137Cs in the lichen was confirmed. Acid rains were shown to influence the extraction of 137Cs. .
Effect of polymorphism of Al2O3 on sintering and grain growth of magnesia aluminate spinel
Authors: Zhihui Z. , Nan L. , Guozhi R.
Published: August 2007

The effect of polymorphism of Al2O3 on sintering and grain growth of magnesia aluminate spinel was studied. ? - Al2O3 and ? - Al2O3 were mixed with MgO according to the stoichiometric MA ratio, respectively, and pressed into billets with a 20mm diameter and 15mm height, and then were sintered at temperature from 1250?C to 1400?C in air atmosphere. Bulk density, apparent porosity and grain size were measured. The results indicated that the grain size of MA with ?-Al2O3 is larger than the grain size of MA with ? - Al2O3. This is because the activation energy of grain growth of magnesia aluminate spinel prepared by ?-Al2O3 is lower than that by ? -Al2O3, the former is 159KJ/mol and the latter is 217KJ/mol.
High pressure sintered ZrO2-6%wt REO
Authors: Kuranaga C. , Bobrovnitchii G.S.
Published: August 2007

The sintering conditions employed in this work are innovative, due to the use of an alternative technology to process ZrO2-REO (rare earth oxide mixture), so called high temperature - high pressure (HPHT). A pressure of 5GPa was used, temperatures of 1100, 1200, and 1300 o C, for times of 2 and 5 minutes. The best results were obtained for samples sintered at 5GPa/1300 o C/5min., where a micro-hardness of 4.8GPa, fracture toughness of 5.3MPa.m ?, density of 97.9%, and 88% in volume of a tetragonal phase retained at room temperature were achieved.
Troubled locations
Authors: Jansen Stef
Published: August 2007

This article confronts the nationalist and foreign interventionist discourses on 'home' in post-war Bosnia-Herzegovina with the everyday experiences of a category of persons who are perceived as the ultimate embodiment of the promised homecoming encapsulated in sedentarism: minority returnees. It ethnographically traces the initially mirroring movements of two households and their differential ways to overcome the effects of displacement as well as their insertion in broader transformations. Infusing the notion of 'home' with an eye for security in its widest sense, and, in particular, highlighting the importance of the life course, it investigates the significance of place through a contextualized household political economy of 'home'. In that way it explores the conditions in which certain remakings of 'home' come to be seen as more feasible than others.
Anatomy of a disaster
Authors: Whitehead Judith
Published: August 2007

This article discusses the networked forms of governance that have arisen as part of roll-out neo-liberal policies in Mumbai, India, focusing on the flood of 26 July 2005 and its aftermath. The municipal government's inaction during and after the flood is attributed to the decentralization of governance, as well as to cutbacks to public health and basic services in recent years. The rise of competitive urbanism as a part of roll-out neo-liberalism is analyzed as producing gaps in disaster management planning and implementation. The article concludes with a call for a refinanced state and a centralization of municipal bodies under a unified municipal council, seen as necessary to provide the professionalized services required during large-scale emergencies such as floods.
Strawberry fields forever?
Authors: Ivancheva Mariya
Published: August 2007

This article is based on fieldwork conducted among Romanian and Bulgarian students working under the Seasonal Agricultural Workers Scheme in the UK. It shows how a public discourse on the benefits of and for immigrant seasonal workers silences the voices of these workers. It also discusses how a hidden transcript of the student workers shows they are deeply frustrated about their exploitation in terms of wages, living conditions, and the fact that they have come to the UK on false promises of cultural exchange and learning. The confinement of Bulgarian and Romanian immigrants—such as these student workers—to the unskilled and underpaid labor sector in the UK, which continues despite Romania and Bulgaria's recent accession to the EU, not only reproduces the dual labor market in the UK itself but it also reduces Romania and Bulgaria to 'second-hand' EU members states.
Methylkarranjic acid and Pongamol from Derris indica Seeds and their Antibacterial Activity
Authors: Baki M Abdullahil , Sadik Golam , Mondal KAM Shahadat Hossain , Mosaddik M Ashilk , Rahman M Mukhlesur
Published: August 2007

Two phenolic compounds, methylkarranjic (1) acid and pongamol (2), were isolated from the petroleum ether soluble fraction of an ethanolic extract of Derris indica seeds. The structures of these compounds were confirmed by LC-MS and a series of 1D and 2D NMR data. The solvent solvent partionates of the ethanolic extract and compounds (1 and 2) exhibited moderate antibacterial activity against several test organisms. The minimum inhibitory concentrations (MICs) of 1 and 2 were found to be in the range of 32-128 μg/ml against Bacillus megatorium, Streptococcus β-haemolyticus, Shigella dysenteriae and E. coli.

Key words: Derris indica; Leguminosae; Methylkarranjic acid; Pongamol; Antibacterial activity

Dhaka Univ. J. Pharm. Sci. 6(1): 9-13, 2007 (June)

The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website
Preparation and Evaluation of Inclusion Complex of the Lipid Lowering Drug Lovastatin with ?-Cyclodextrin
Authors: Patel RP , Patel MM
Published: August 2007

Several attempts have been made to improve the solubility of water insoluble drugs. Over the years, inclusion complexation of drugs with ?-cyclodextrin has emerged as a viable attempt to improve the dissolution of water insoluble drugs. The aim of the present work was to improve the dissolution rate of lovastatin, a water insoluble drug, by inclusion complexation with ?-cyclodextrin. The stoichiometric ratio determined by phase solubility analysis for inclusion complexation of lovastatin with ?-cyclodextrin was 1:1. The solubility of lovastatin increased with increasing amount of ?-cyclodextrin in water. Gibbs free energy (?Gtr°) values were all negative, indicating the spontaneous nature of lovastatin solubilization. Complexes of lovastatin were prepared with ?-cyclodextrin by various methods such as kneading, coevaporation and physical mixing. The complexes were characterized by Fourier-transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and X-ray diffraction (XRD) patterns. These studies indicated the inclusion of lovastatin in the cavity of ?-cyclodextrin. The complexation resulted in a marked improvement in the solubility of lovastatin. The complex prepared by kneading method showed fastest and highest in vitro dissolution rate compared to the tablets of pure of lovastatin. Physical mixture of ?-cyclodextrin/lovastatin also showed significant improvement in the dissolution rate compared to pure lovastatin. Mean dissolution time (MDT) of lovastatin decreased significantly after preparation of complexes and physical mixture of lovastatin with ?-cyclodextrin. Similarity factor (f2) indicated significant difference between the release profiles of lovastatin from complexes and from pure lovastatin.

Key words: Lovastatin, ?-cyclodextrin, inclusion complexation, in vitro dissolution studies.

Dhaka Univ. J. Pharm. Sci. 6(1): 25-36, 2007 (June)

The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website
Antioxidant Effect of Spirulina in Long Evans Rat
Authors: Hossain M Sabir , Mohamad Akim Uddin , Alam Md. Shafiul , Hossain Md. Aktar , Rahman Md. Shafiqur , Haque Md. Enamul
Published: August 2007

Spirulina, a naturally occurring micro algae, was suspended in water and administrated orally to streptozotocin induced diabetic and nondiabetic rats at a dose of 400 mg per kg body weight. The animal of the control group was administrated extract of Spinacea oleracea (locally known as Palong Shak). Thirty days after the oral administration all the rats were sacrificed for the determination of super oxide dismutase. Spirulina increased the level of oxidative stress responsive enzyme Super oxide dismutase (SOD) in erythrocyte by 17.5% (p<0.0005) in diabetic rats suggesting that the herb may have antioxidant properties.

Key words: Diabetes Mellitus, Spirulina, Rat

Dhaka Univ. J. Pharm. Sci. 6(1): 43-45, 2007 (June)

The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website
Analgesic Activity of Bark of Hibiscus mutabilis
Authors: Ghogare PB , Bhalke RD , Girme AS , Nirmal SA , Jadhav RS , Tambe VD
Published: August 2007

Dhaka Univ. J. Pharm. Sci. 6(1): 55-57, 2007 (June)

The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website
Bioactivities of Sesbania sesban Extractives
Authors: Hossain Md. Alamgir , Rahman Mohammad S , Chowdhury AM Sarwaruddin , Rashid Mohammad A
Published: August 2007

Dhaka Univ. J. Pharm. Sci. 6(1): 61-63, 2007 (June)

The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website
General Photo‐Patterning of Polyelectrolyte Thin Films via Efficient Ionic Bis(Fluorinated Phenyl Azide) Photo‐Crosslinkers and their Post‐Deposition Modification
Authors: Khong S.‐H. , Sivaramakrishnan S. , Png R.‐Q. , Wong L.‐Y. , Chia P.‐J. , Chua L.‐L. , Ho P. K. H.
Published: August 2007

We have extended the well known bisfluorinated(phenyl azide) (bisFPA) methodology to develop an ionic bisFPA process suitable for photo‐crosslinking a wide variety of polyelectrolyte thin films. The crosslinking efficiencies (0.1–1.0 crosslink per photo‐reaction) are sufficiently high for the gel fraction to exceed 80 % for crosslinker concentrations of only a few weight %. This method is based on the photo‐induced formation of singlet nitrenes from FPAs and their insertion into unactivated C–H or other bonds, which thus general and not dependent on the presence of specific chemical functional groups. By derivatizing with ionic charge groups, we obtained ionic bisFPAs that can be properly dispersed into polyelectrolyte thin films. The sorbed moisture always present in these films however severely limits the photo‐crosslinking efficiency, apparently through nitrene protonation and intersystem crossing. This can be avoided by dehydration of the films, in some cases, to 130 °C for 10 min in nitrogen before photo‐exposure. We found that efficient photo‐crosslinking can then be achieved for polyelectrolytes even when they have nucleophilic groups. These include poly(styrenesulfonic acid) and their salts, poly(acrylic acid) and their salts, poly(dimethyldiallylammonium salts), as well as the electrically‐conducting poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonic acid) complex (PEDT:PSSH). We further demonstrate using this ionic bisFPA methodology both photo‐patterning and post‐deposition chemical modifications of polyelectrolyte thin films. This opens broad new possibilities in membrane, sensor and actuator technologies, as well as for organic semiconductor plastic electronics (such as field‐effect transistors) and polyelectrolyte‐based devices.
Interfacial Effect on Dielectric Properties of Polymer Nanocomposites Filled with Core/Shell‐Structured Particles
Authors: Shen Y. , Lin Y. H. , Nan C.‐W.
Published: August 2007

Novel polymer nanocomposites were prepared by solution processing with core/shell structured nanoparticles (carbonaceous shell coating on silver cores) as fillers. The organic carbonaceous shells act as interlayers between the Ag cores as well as with the polymer matrix. It is shown that the electrical properties of the interlayers play a dominative role in determining the dielectric behavior of the nanocomposites. Insulating interlayers reduce the tunnel current between neighboring Ag cores by causing potential barriers, endowing the nanocomposites with stable and high dielectric constants and low dielectric loss. Furthermore, the stable dielectric constants of the nanocomposites could be tuned by adjusting the thickness of the interlayers. Increasing the conductivity of the interlayers lowers the potential barriers, making the dielectric behavior of the nanocomposites more similar to that of conventional percolative composites.
Growth among Tibetans at high and low altitudes in India
Authors: Tripathy Vikal , Gupta Ranjan
Published: August 2007

In India, Tibetans have been living at different altitudes for more than 40 years. This study describes physical growth in terms of height, weight, sitting height, skinfold thickness at triceps and upper arm circumference of Tibetans born and raised at three Tibetan refugee settlements (3,521; 970; and 800 m) from the view point of the hypothesis that growth is retarded at high altitude. Samples consist of individuals between the ages of 2 and 40 years. Tibetans at high altitude in India show a growth pattern similar to that previously observed among Tibetans in Tibet. Tibetans at high altitude are taller and heavier compared to Andean highlanders. The general trends show that Tibetan children and adults of both sexes at low altitude in India are advanced in terms of height, weight, skinfold thickness at triceps and upper arm circumference compared to Tibetans at high altitude. Trunk length (sitting height) is similar at the two altitudes but relative sitting height is greater at high altitude. Greater relative sitting height and lesser leg length at high altitude than at low altitudes is discussed in terms of effect of altitude, temperature, and nutritional status. Am. J. Hum. Biol., 2007. © 2007 Wiley‐Liss, Inc.
Improving dispersion of multiwalled carbon nanotubes in polyamide 6 composites through amino‐functionalization
Authors: Li Juan , Fang Zhengping , Tong Lifang , Gu Aijuan , Liu Fu
Published: August 2007

The focus of this study is to investigate the state of dispersion of different treated multiwalled carbon nanotubes (MWNTs) in polyamide 6 (PA6). The MWNTs used in composites were grafted by 1,6‐hexamethylenediamine (HMD) via acid‐thionyl chloride to improve their compatibility with PA6 matrix. A microstructure transformation of MWNTs is found during the treatment process. Acidification makes the MWNTs compact and grafting HMD promotes the compact structure loose again. The MWNTs after different treatment were used to fabricate MWNTs/PA6 composites through melt blending. The dispersion of different MWNTs in PA6 was observed by a combination of scanning electron microscopy, optical microscopy, and transmission electron microscopy. The results show that the amino‐functionalized MWNTs are dispersed more homogeneously in PA6 than the purified MWNTs, and the poorest dispersion is achieved for acid treated MWNTs. It is indicated that the loose structure and functionalized surface of MWNTs benefit the dispersion of MWNTs in PA6. In addition, the amino‐functionalization of MWNTs improves the compatibility between the MWNTs and PA6, resulting in stronger interfacial adhesion. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Synthesis and characterization of biodegradable network poly(ethylene glycol) films with elastic properties
Authors: Nagata Minoru , Sugiura Ryosuke , Sakai Wataru , Tsutsumi Naoto
Published: August 2007

Novel biodegradable network films with elastic properties were prepared from trimesic acid (Y) and poly(ethylene glycol)s (PEGs) with different molecular weights (MW) and/or 4,7,10‐trioxa‐1,13‐tridecanediamine (I). Prepolymers prepared by a melt polycondensation were cast from N,N′‐dimethylformamide solution and postpolymerized at 290°C for various times to form a network. The resultant films were transparent, flexible, and insoluble in organic solvents. The X‐ray diffraction scattering pattern showed that all network films are amorphous. The densities of the network films decreased, whereas their water uptake increased with increasing MWs of PEG. The thermal and tensile properties were measured in dry and wet conditions and were affected remarkably not only by MWs of PEG, but also by the water uptake of the films. The glass transition temperatures (Tg) decreased with increasing MWs of PEG. YPEG200 and YPEG1000 films showed good elastomeric properties with an ultimate elongation of 225 and 277%, respectively, in dry condition. The tensile strength of 13 MPa and Young's modulus of 214 MPa were the highest for YPEG200 among the network elastic films studied. All sample films in wet condition had lower Tg's and tensile properties. The hydrolytic degradation was measured by the weight loss of network films in a buffer solution with or without Rhizopus delemar lipase at 37°C. The degree and the rate of the degradation increased with increasing MWs of PEG, which is compatible with the increase in water uptake of the films. Incorporation of large amount of I moiety into YPEG1000 film increased the glass transition temperatures, tensile strength and Young's modulus, but depressed elastic nature of the films. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Flame retardant polyesters. I. Phosphorous flame retardants
Authors: Yang Seung‐Cheol , Kim Jae Pil
Published: August 2007

Commercially available two types of phosphorous flame retardants (FRs) for polyester were compared from the viewpoint of chemical reactivity, reaction mechanism, and byproduct formation. 3‐(Hydroxyphenyl phosphinyl) propanoic acid (HPP) and 9,10‐dihydro‐9‐oxa‐10‐2,3‐dicarbonylpropyl)‐10‐phosphophenanthrene‐10‐oxide (DI) were used as a main chain type and a pendant type, respectively. HPP and DI showed different behavior with ethylene glycol (EG). More acidic HPP reacted with EG spontaneously and then produced esterified terminal hydroxy end group reacted with EG to form terminal diethylene glycol (DEG) end group. But the composition in the HPP solution was not varied for a long time below the esterification temperature. Contrast to HPP, DI showed normal esterification procedure. DI esterified with EG to form DI ester of EG, and DEG formation is not distinct. The difference of reactivity and DEG formation is caused by the difference of acidity in EG solution. For production of phosphorous containing polyester, it is desirable that HPP is introduced into the reactor in the mere solution state and DI in the esterified state. In addition, for production of polyester having the same phosphorous content in commercial scale, it is more beneficial to apply HPP than DI because of low input of FR due to low molecular weight. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Synthesis and characterization of the chiral stationary phase based on chitosan
Authors: Son Seung‐Hee , Jegal Jonggeon
Published: August 2007

Chitosan was modified with N‐nicotinoyl‐L‐phenylalanine and 3,5‐dimethylphenylisocyanate to prepare a chiral stationary phase for the high performance liquid chromatography application, especially for the separation of optical isomers of series of α‐amino acids. The modified chitosan with N‐nicotinoyl‐L‐phenylalanine group and 3,5‐dimethylphenylcarbamate group was characterized with several analytical methods such as differential scanning calorimeter, thermo gravimetric analyzer, X‐ray diffractometer, and HPLC; its solubility, thermal property, and chiral separation performance were studied. Contrary to chitosan, the modified chitosan prepared in this study showed good solubility in several organic solvents and was easy to handle to coat the silica particles to prepare chiral HPLC column. It showed good chiral separation capabilities. It was also thermally stable at over 100°C, suggesting potential wide operating temperature range of its chiral HPLC column. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Thermodynamics of Hydrophobic Interactions: Entropic Recognition of a Hydrophobic Moiety by Poly(Ethylene Oxide)–Zinc Porphyrin Conjugates
Authors: Iwamoto Hiroya , Mizutani Tadashi , Kano Koji
Published: August 2007

The recognition of 4‐alkylpyridines by water‐soluble poly(ethylene oxide)–zinc porphyrin conjugates was studied with a focus on the thermodynamic parameters of binding. Microcalorimetric studies indicated that binding of the alkyl group of the guest in water is driven by the entropic term (δΔH0=ΔH0(4‐pentylpyridine)− ΔH0(4‐methylpyridine)=+1.7 kJ mol−1, δTΔS0=TΔS0(4‐pentylpyridine)− TΔS0(4‐methylpyridine)=+11.8 kJ mol−1 at 298 K), thus showing the significance of water reorganization during host–guest interaction. The enthalpy–entropy compensation temperature of binding of 4‐alkylpyridines was as low as 38 K; only below this temperature could the enthalpic term be a driving force. The binding affinity was modulated by the addition of cations and by varying the degree of polymerization of poly(ethylene oxide), which suggests that guest binding is coupled with polymer conformation.
CD38 regulates oxytocin secretion and complex social behavior
Authors: Bartz Jennifer A. , McInnes L. Alison
Published: August 2007

The peptide hormone oxytocin plays a critical role in regulating affiliative behaviors including mating, pair‐bond formation, maternal/parenting behavior, social recognition, separation distress and other aspects of attachment. Jin and colleagues1 recently reported intriguing findings that CD38, a transmembrane receptor with ADP‐ribosyl cyclase activity, plays a critical role in maternal nurturing behavior and social recognition by regulating oxytocin secretion. This research may have implications for understanding disorders marked by deficits in social cognition and social functioning, including autism, social anxiety disorder, borderline personality disorder and schizophrenia. BioEssays 29:837–841, 2007. © 2007 Wiley Periodicals, Inc.
Scalaradial, a Dialdehyde‐Containing Marine Metabolite That Causes an Unexpected Noncovalent PLA2 Inactivation
Authors: Monti Maria Chiara , Casapullo Agostino , Cavasotto Claudio N. , Napolitano Assunta , Riccio Raffaele
Published: August 2007

Several marine terpenoids that contain at least one reactive aldehyde group, such as manoalide and its congeners, possess interesting anti‐inflammatory activities that are mediated by the covalent inactivation of secretory phospholipase A2 (sPLA2). Scalaradial, a 1,4‐dialdehyde marine terpenoid that was isolated from the sponge Cacospongia mollior, is endowed with a relevant anti‐inflammatory profile, both in vitro and in vivo, through selective sPLA2 inhibition. Due to its peculiar dialdehyde structural feature, it has been proposed that scalaradial exerts its enzymatic inactivation by means of an irreversible covalent modification of its target. In the context of our on‐going research on anti‐PLA2 natural products and their interaction at a molecular level, we studied scalaradial in an attempt to shed more light on the molecular mechanism of its PLA2 inhibition. A detailed analysis of the reaction profile between scalaradial and bee venom PLA2, a model sPLA2 that shares a high structural homology with the human synovial enzyme, was performed by a combination of spectroscopic techniques, chemical reactions (selective modifications, biomimetic reactions), and classical protein chemistry (such as proteolytic digestion, HPLC and mass spectrometry), along with molecular modeling studies. Unexpectedly, our data clearly indicated the noncovalent forces to be the leading event in the PLA2 inactivation process; thus, the covalent modification of the enzyme emerges as only a minor side event in the ligand–enzyme interaction. The overall picture might be useful in the design of SLD analogues as new potential anti‐inflammatory compounds that target sPLA2 enzymes.
Transient early embryonic expression of Nkx2‐5 mutations linked to congenital heart defects in human causes heart defects in Xenopus laevis
Authors: Bartlett Heather L. , Sutherland Lillian , Kolker Sandra J. , Welp Chelsea , Tajchman Urszula , Desmarais Vera , Weeks Daniel L.
Published: August 2007

Nkx2‐5 is a homeobox containing transcription factor that is conserved and expressed in organisms that form hearts. Fruit flies lacking the gene (tinman) fail to form a dorsal vessel, mice that are homozygous null for Nkx2‐5 form small, deformed hearts, and several human cardiac defects have been linked to dominant mutations in the Nkx2‐5 gene. The Xenopus homologs (XNkx2‐5) of two truncated forms of Nkx2‐5 that have been identified in humans with congenital heart defects were used in the studies reported here. mRNAs encoding these mutations were injected into single cell Xenopus embryos, and heart development was monitored. Our results indicate that the introduction of truncated XNkx2‐5 variants leads to three principle developmental defects. The atrial septum and the valve of the atrioventricular canal were both abnormal. In addition, video microscopic timing of heart contraction indicated that embryos injected with either mutant form of XNkx2‐5 have conduction defects. Developmental Dynamics 236:2475–2484, 2007. © 2007 Wiley‐Liss, Inc.
Zebrafish homologue irx1a is required for the differentiation of serotonergic neurons
Authors: Cheng Chi Wa , Yan Carol Hiu Mei , Choy Siu Wah , Hui Michelle Nga Yu , Hui Chi‐Chung , Cheng Shuk Han
Published: August 2007

Serotonergic (5HT) neurons produce neurotransmitter serotonin, which modulates various neuronal circuits. The specification and differentiation of 5HT neurons require both extrinsic signals such as Shh and Fgf, as well as intrinsic transcription factors such as nkx2.2, mash1, phox2b, Gata2, and pet1. In this study, we show that iroquois homeodomain factor irx1a, but not irx1b, is expressed in the 5HT neurons. Knockdown of irx1a by antisense morpholino nucleotides reveals that it is a critical determinant for the differentiation of 5HT neurons in the hindbrain. However, irx1a morphants do not show a reduction of the progenitors of 5HT neurons. Hence, irx1a is not required for the initial specification but it is required for the complete differentiation of 5HT neurons. Developmental Dynamics 236:2661–2667, 2007. © 2007 Wiley‐Liss, Inc.
Sclerotomal origin of smooth muscle cells in the wall of the avian dorsal aorta
Authors: Wiegreffe Christoph , Christ Bodo , Huang Ruijin , Scaal Martin
Published: August 2007

The dorsal aorta is the earliest formed intraembryonic blood vessel. It is composed of an inner lining consisting of endothelial cells and an outer wall consisting of smooth muscle cells (SMCs) and fibrocytes. Aortic SMCs have been suggested to arise from several developmental lineages. Cephalic neural crest provides SMCs of the proximal part of the aorta, and SMCs of the distal part are derived from the paraxial mesoderm. Here, we show by using quail‐chick chimerization that in the avian embryo, SMCs in the wall of the dorsal aorta at trunk level arise from the sclerotome. Our findings indicate a two‐step process of aortic wall formation. First, non‐paraxial mesoderm‐derived mural cells accumulate at the floor of the aorta. We refer to these cells as primary SMCs. Second, SMCs from the sclerotome are recruited to the roof and sides of the aorta, eventually replacing the primary SMCs in the aortic floor. Developmental Dynamics 236:2578–2585, 2007. © 2007 Wiley‐Liss, Inc.
Integrin α5 is required for somite rotation and boundary formation in Xenopus
Authors: Kragtorp Katherine A. , Miller Jeffrey R.
Published: August 2007

The morphogenesis of somites in Xenopus laevis is characterized by a complex process of cell turning that requires coordinated regulation of cell shape, adhesion, and motility. The integrin α5 subunit has been implicated in the formation of somite boundaries in organisms utilizing epithelialization to create morphologically distinct somites, but its function has not been examined in Xenopus. We used a splice‐blocking morpholino to knock down expression of integrin α5 during somite formation. Loss of integrin α5 delayed somite turning and accumulation of integrin β1 at somite boundaries, and disrupted the fibronectin matrix surrounding developing somites. Irregular somite boundaries with a sparse and discontinuous fibronectin matrix formed upon eventual completion of somite turning. Recovery of somite morphology was improved, but still incomplete in far posterior somites. These data demonstrate that the role of integrin α5 in somite boundary formation is conserved in a species using a unique mechanism of somitogenesis. Developmental Dynamics 236:2713–2720, 2007. © 2007 Wiley‐Liss, Inc.
On the Mechanism of Palladium‐Catalyzed Cross‐Coupling of Diazonium Salts with Aryltrifluoroborates: A Combined ESI‐MS/NMR Study
Authors: Taccardi Nicola , Paolillo Rossella , Gallo Vito , Mastrorilli Piero , Nobile Cosimo F. , Räisänen Minna , Repo Timo
Published: August 2007

A combined ESI‐MS/NMR mechanistic study on the palladium‐catalysed cross‐coupling reaction between aryldiazonium salts and aryltrifluoroborates with bis(μ‐acetato)bis(4,4′‐difluoroazobenzene‐C2,N)dipalladium(II) (4) as the precatalyst is reported. The reaction follows a Pd0/PdII cycle after reduction of 4 to a molecular Pd0 species (I), which according to the combined ESI‐MS and 19F NMR studies, bears an arylated azobenzene ligand. Oxidative addition by the diazonium salt generates the arylpalladium(II) intermediate (II), which was also detected in solution. The catalytic cycle is completed with a transmetallation between II and theorganoborate, which is followed by fast reductive elimination of the cross‐coupling product to restore the molecular Pd0 species I. A concurrent activation path was also observed which consists of the formation of (4,4′‐difluoroazobenzene‐C2,N)dipalladium(II) tetrafluoroborate (7) by the reaction of 4 with the diazonium salt and subsequent reduction by the aryltrifluoroborate to give I. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Identification of cis‐12,cis‐15 octadecadienoic acid and other minor polyenoic fatty acids in ruminant fat
Authors: Alves Susana P. , Bessa Rui J. B.
Published: August 2007

The fatty acid pattern of ruminant edible fats is very complex and its diversity is mostly determined by extensive interactions between dietary factors and rumen metabolism. Characterization of intermediates of polyunsaturated fatty acid (PUFA) biohydrogenation in lipids from ruminants, particularly when supplemented with oils, can be a rather difficult task. In this study, we characterized some minor PUFA that occur in muscle samples from linseed oil‐fed lambs, by covalent adduct chemical ionization tandem mass spectrometry (CACI‐MS/MS) using acetonitrile as reagent of chemical ionization. Two minor metabolites, cis‐12,cis‐15 18:2 and cis‐9,trans‐11,cis‐15 18:3 were identified for the first time in lamb meat through CACI‐MS/MS. However, the cis‐9,trans‐11,cis‐15 18:3 isomer was incompletely resolved from 20:3n‐9 under our GC/MS conditions. Thus, in studies reporting biohydrogenation intermediates in meat, caution must be taken in order to ensure proper resolution of these two fatty acid methyl esters (FAME) and therefore avoid quantitative overestimations. CACI‐MS/MS was a powerful and rapid method for the structural characterization of minor polyenoic FAME present in ruminant fat, and it seems to be a good alternative to classic 4,4‐dimethyloxazoline and picolinyl derivatization methods.
Monitoring long‐memory air quality data using ARFIMA model
Authors: Pan Jeh‐Nan , Chen Su‐Tsu
Published: August 2007

Statistical control chart is commonly used in the industry to help ensure stability of manufacturing process and it can also be used to monitor the environmental data, such as industrial waste or effluent of manufacturing process. However, control chart needs to be modified if the set of environmental data exhibits the property of long memory. In this paper, a control chart for autocorrelated data using autoregressive fractionally integrated moving‐average (ARFIMA) model is proposed to monitor the long‐memory air quality data. Finally, we use the air quality data of Taiwan as examples to compare the difference between ARFIMA and autoregressive integrated moving‐average (ARIMA) models. The results show that residual control charts using ARFIMA models are more appropriate than those using ARIMA models. Copyright © 2007 John Wiley & Sons, Ltd.
Arterial ammonia and clinical risk factors for encephalopathy and intracranial hypertension in acute liver failure
Authors: Bernal William , Hall Catherine , Karvellas Constantine J. , Auzinger Georg , Sizer Elizabeth , Wendon Julia
Published: August 2007

High circulating ammonia concentrations are common in patients with acute liver failure (ALF) and are associated with hepatic encephalopathy (HE) and intracranial hypertension (ICH). Other risk factors are poorly characterized. We evaluated the relation of the admission arterial ammonia concentration and other clinical variables with the development of HE and ICH. Arterial ammonia was measured on admission to the intensive care unit in 257 patients; 165 had ALF and severe HE, and there were 3 control groups: acute hepatic dysfunction without severe HE (n = 50), chronic liver disease (n = 33), and elective surgery (n = 9). Variables associated with ICH and HE were investigated with regression analysis. Ammonia was higher in ALF patients than controls. An independent risk factor for the development of severe HE and ICH, a level greater than 100 μmol/L predicted the onset of severe HE with 70% accuracy. The model for end-stage liver disease (MELD) score was also independently predictive of HE, and its combination with ammonia increased specificity and accuracy. ICH developed in 55% of ALF patients with a level greater than 200 μmol/L, although this threshold failed to identify most cases. After admission, ammonia levels remained high in those developing ICH and fell in those who did not. Youth, a requirement for vasopressors, and renal replacement therapy were additional independent risk factors.

Conclusion:

Ammonia is an independent risk factor for the development of both HE and ICH. Additional MELD scoring improved the prediction of HE. Factors other than ammonia also appear important in the pathogenesis of ICH. Ammonia measurements could form part of risk stratification for HE and ICH, identifying patients for ammonia-lowering therapies and invasive monitoring. (Hepatology 2007.)
Epidemiologic findings on serologically defined chronic atrophic gastritis strongly depend on the choice of the cutoff‐value
Authors: Brenner Hermann , Rothenbacher Dietrich , Weck Melanie N.
Published: August 2007

Chronic atrophic gastritis (CAG), a precursor of intestinal gastric cancer, is mostly ascertained noninvasively by serum pepsinogens in epidemiologic studies. However, serological definitions vary widely. We aimed to investigate the impact of this variation on estimated prevalence of CAG and its association with its main risk factors, age and Helicobacter pylori infection. Serum pepsinogen I and II and antibodies against H. pylori were measured by ELISA among 9,444 women and men aged 50–74 years in a population‐based cohort study in Saarland/Germany. Application of the various definitions resulted in a wide range of prevalence estimates of CAG prevalence (2.1%–8.2%, with an outlier of 18.8% for one particular definition) and its associations with age and H. pylori infection (age adjusted odds ratios, OR, for CagA positive H. pylori infection: 0.98–4.48). Definitions of CAG based on both pepsinogen I and the pepsinogen I/II ratio or on the pepsinogen I/II ratio only revealed much clearer associations with both age and H. pylori infection than definitions of CAG based on pepsinogen I only (ORs for H. pylori infection: 1.45–4.48 and 0.86–1.30, respectively). Epidemiologic findings on CAG lack comparability due to the heterogeneity in serologic definitions of CAG. The association of age and H. pylori infection with CAG may be strongly underestimated in studies in which CAG is defined by pepsinogen I only. © 2007 Wiley‐Liss, Inc.