bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitroimidazoles. V. Synthesis and anti-HIV evaluation of new 5-substituted piperazinyl-4-nitroimidazole derivatives
Authors: Al-Soud Yaseen , Al-Masoudi Najim , Hassan Hamed , De Clercq Erik , Pannecouque Christophe 
Published: January 2008

Nitroimidazoles. V. Synthesis and anti-HIV evaluation of new 5-substituted piperazinyl-4-nitroimidazole derivativesA series of 2-alkylthio-1-[4-(1-benzyl-2-ethyl-4-nitro-1H- -imidazol-5-yl)-piperazin-1-y]lethanones (3-9) and alkyl- [4-(1-benzyl-2-ethyl-4-nitro-1H-imidazol-5-yl)-piperazin- -1-yl)ketones (11-20) as well as the indole analogue22were synthesized from 4-nitro-5-piperazinyl imidazole derivative1, with the aim to develop newly non-nucleoside reverse transcriptase inhibitors (NNRTIs). The newly synthesized compounds were assayed against HIV-1 and HIV-2 in MT-4 cells. Compound2showed inhibition of HIV-1 (EC50 0.45 mg mL-1) and HIV-2 (0.50 mg mL-1), while9showed inhibition of HIV-1 (EC502.48 mg mL-1, SI = 4).
Ketorolac-dextran conjugates: Synthesis, in vitro and in vivo evaluation
Authors: Vyas Savita , Trivedi Piyush , Chaturvedi Subhash 
Published: January 2008

Ketorolac-dextran conjugates: Synthesis,in vitroandin vivoevaluationKetorolac is a non-steroidal anti-inflammatory drug. Dextran conjugates of ketorolac (KD) were synthesized and characterized to improve ketorolac aqueous solubility and reduce gastrointestinal side effects. An N-acylimidazole derivative of ketorolac (KAI) was condensed with a model carrier polymer, dextran of different molecular masses (40000, 60000, 110000 and 200000). IR spectral data confirmed formation of ester bonding. Ketorolac contents were evaluated by UV-spectrophotometric analysis. The molecular mass was determined by measuring viscosity using the Mark-Howink-Sakurada equation. Invitrohydrolysis studies were performed in aqueous buffers (pH 1.2, 7.4, 9) and in 80% (V/V) human plasma (pH 7.4). At pH 9, a higher rate of ketorolac release from KD was observed as compared to aqueous buffer of pH 7.4 and 80% human plasma (pH 7.4), following first-order kinetics.In vivobiological screening in mice and rats indicated that conjugates retained analgesic and anti-inflammatory activities with significantly reduced ulcerogenicity compared to the parent drug.
Chitosan inserts for periodontitis: Influence of drug loading, plasticizer and crosslinking on in vitro metronidazole release
Authors: Barat Romi , Srinatha Anegundha , Pandit Jayanta , Anupurba Shampa , Mittal Neelam 
Published: January 2008

Chitosan inserts for periodontitis: Influence of drug loading, plasticizer and crosslinking onin vitrometronidazole releaseChitosan based metronidazole (MZ) inserts were fabricated by the casting method and characterized with respect to mass and thickness uniformity, metronidazole loading andin vitrometronidazole release kinetics. The fabricated inserts exhibited satisfactory physical characteristics. The mass of inserts was in the range of 5.63 ± 0.42 to 6.04 ± 0.89 mg. The thickness ranged from 0.46 ± 0.06 to 0.49 ± 0.08 mm. Metronidazole loading was in the range of 0.98 ± 0.09 to 1.07 ± 0.07 mg except for batch CM3 with MZ loading of 2.01 ± 0.08 mg. The inserts exhibited an initial burst release at the end of 24 h, irrespective of the drug to polymer ratio, plasticizer content or cross-linking. However, further drug release was sustained over the next 6 days. Cross-linking with 10% (m/m) of glutaraldehyde inhibited the burst release by ~30% and increased the mean dissolution time (MDT) from 0.67 to 8.59 days. The decrease in drug release was a result of reduced permeability of chitosan due to cross-linking.
A Novel and Efficient Synthesis of Tocopheryl Quinones by Homogeneous and Heterogeneous Methyltrioxorhenium/Hydrogen Peroxide Catalytic Systems
Authors: Saladino Raffaele , Neri Veronica , Farina Angela , Crestini Claudia , Nencioni Lucia , Palamara Anna Teresa 
Published: January 2008

AbstractA convenient and efficient application of heterogeneous poly(4‐vinylpyridine), poly(4‐vinylpyridine N‐oxide), and polystyrene/methylrhenium trioxide systems for the selective oxidation of tocopherols and tocopherol derivatives to the corresponding ortho‐ and para‐tocopherylquinones is described. Environment friendly, easily available, and low‐cost hydrogen peroxide (H2O2) was used as the oxygen atom donor. The antiviral activity of the newly synthesized tocopherylquinones and their parent tocopherols against influenza A virus is also reported. On the basis of the biological assay, the activity of tocopherols against influenza virus is higher than that showed by the corresponding tocopherylquinones, thus suggesting, for the first time, a drawback effect of the oxidative metabolism on the antiviral activity of these compounds.
Fast Suzuki–Miyaura Cross‐Coupling Reaction with Hexacationic Triarylphosphine Bn‐Dendriphos as Ligand
Authors: Snelders Dennis J. M. , Kreiter Robert , Firet Judith J. , van Koten Gerard , Klein Gebbink Robertus J. M. 
Published: January 2008

AbstractThe application of hexa[(dimethylamino)methyl]‐functionalized triphenylphosphine (1) and its benzylammonium salt, Bn‐Dendriphos (2), in the Suzuki–Miyaura cross‐coupling of aryl bromides with arylboronic acids is described. The 3,5‐bis[(benzyldimethylammonio)methyl] substitution pattern in 2 leads to a rate enhancement compared to both the non‐ionic parent compound 1 and triphenylphospine (PPh3) itself. At the same time, the resulting catalytic species are stable towards palladium black formation, even at a phosphine/palladium ratio of 1. These observations are attributed to the presence of a total of six ammonium groups in the backbone of the phosphine ligand, which presumably leads to an unsaturated phosphine‐palladium complex.
Ratiometric and selective fluorescent chemodosimeter for Cu(II) by Cu(II)‐induced oxidation
Authors: Xiang Yu , Tong Aijun 
Published: January 2008

AbstractA new rhodamine derivative, rhodamine B 4‐N,N‐dimethylaminobenzaldehyde hydrazone (1), was designed for ratiometric sensing of Cu(II) selectively. A red‐shift from 515 to 585 nm was observed in the fluorescence spectrum when Cu(II) was added to 1 in acetonitrile. Other metal ions of interest showed no ratiometric response. The interaction between Cu(II) and 1 was found to be the Cu(II)‐induced oxidation of 1. Copyright © 2008 John Wiley & Sons, Ltd.
Chemiluminescence determination of bromhexine hydrochloride with morin as chemiluminescent reagent
Authors: Jiang Qingqing , Nie Fei , Lu Jiuru 
Published: January 2008

AbstractA new chemiluminescence (CL) reaction was observed when cerium(IV) solution was injected into bromhexine hydrochloride–morin solution. Based on this, a flow‐injection CL method for the determination of bromhexine hydrochloride was established. A possible mechanism of the CL reaction was proposed via the investigation of the CL kinetic characteristics, the CL spectrum and the fluorescence spectra of some related substances. Under optimum conditions, the CL signal was correlated linearly with concentration of bromhexine hydrochloride over the range 2.0 × 10–9–2.0 × 10–7 g/mL, with a linear correlation of 0.9995. The detection limit was 9 × 10–10 g/mL bromhexine hydrochloride and the relative standard deviation was 1.0% (c = 2.0 × 10–8 g/mL bromhexine hydrochloride, n = 11). The method was applied to the determination of bromhexine hydrochloride in pharmaceutical preparations and human urine samples with satisfactory results. Copyright © 2008 John Wiley & Sons, Ltd.
Effect of methacrylic monomers on phagocytes reactive oxygen species: a possible BDDMA modulating action
Authors: Nocca Giuseppina , Lupi Alessandro , De Santis Fabio , Giardina Bruno , De Palma Francesco , Chimenti Claudio , Gambarini Gianluca , De Sole Pasquale 
Published: January 2008

AbstractIn the last years the studies regarding the biocompatibility of dental materials investigate, in addition to the classic cytotoxic tests, the interactions between the materials and the host cells to better explain the causes of the adverse effects observed sometimes in the clinical practice. In the present study the ability of diurethane dimethacrylate (DUDMA) and 1,4‐butanediol dimethacrylate (BDDMA) methacrylic monomers present in dental composite resins to alter the functionality of peripheral blood monocytes (PBMs) and polymorphonucleate cells (PMNs) was examined. These cells are involve in the biological response to materials and in the host ability to respond to bacteria. The results obtained suggest that the examined methacrylates induce a relevant decrease of PBMs oxidative burst whereas the basal ROS production is only slightly decreased. In PMNs DUDMA induces a decrease of both basal and stimulated ROS production. BDDMA, on the contrary, it does not alter total oxidative burst in presence of stimulus while induces a statistically significant decrease of basal ROS production. Moreover this monomer alters the reaction kinetics of stimulated ROS production. The reported finding seems to indicate that this molecule could be able to stabilize PMNs in resting state and maximize their stimulated activity. Copyright © 2008 John Wiley & Sons, Ltd.
Renin‐angiotensin system inhibitors, angiotensin I‐converting enzyme gene insertion/deletion polymorphism, and cancer
Authors: van der Knaap Ronald , Siemes Claire , Coebergh Jan‐Willem W. , van Duijn Cornelia M. , Hofman Albert , Stricker Bruno H. Ch. 
Published: January 2008

AbstractBACKGROUND.Angiotensin I‐converting enzyme (ACE) inhibitors, angiotensin II antagonists, and the ACE insertion/deletion (I/D) gene polymorphism all influence serum angiotensin II action. Because angiotensin II levels have been associated with cancer, the objective of the current epidemiologic study was to investigate whether renin‐angiotensin system inhibitors and/or ACE genotypes were associated with an altered risk of colorectal, lung, breast, and prostate cancer.METHODS.Data were obtained from the Rotterdam Study, a population‐based, prospective cohort study with 7983 participants. Participants who had a history of 1 of the cancers of interest (n = 216) or who had a medication history <6 months (n = 88) were excluded, leaving 7679 participants, of whom the ACE genotypes could be assessed in 6670 individuals. The mean follow‐up was 9.6 years, during which 730 incident cancers occurred. The effect of medication, ACE I/D genotypes, and their interaction on cancer risk and progression was studied by using Cox proportional hazard models.RESULTS.Carriers of the high‐activity genotype DD had an increased risk of breast cancer compared with low‐activity II/ID genotype carriers (hazard ratio [HR], 1.47; 95% confidence interval [95% CI], 1.05–2.04), but no association was demonstrated for other cancers. DD carriers who were exposed to long‐term and high‐dose medication were at lower risk for cancer (HR, 0.28; 95% CI, 0.10–0.79). Short‐term, high‐dose users were at risk for colorectal cancer progression in the II/ID stratum (HR, 3.83; 95% CI, 1.67–8.79).CONCLUSIONS.Renin‐angiotensin system‐inhibiting drugs seemed to protect against cancer in individuals with the DD genotype, which was associated with high levels of ACE. Cancer 2008. © 2008 American Cancer Society.
Sir Humphry Davy: Boundless Chemist, Physicist, Poet and Man of Action
Authors: Thomas Sir John Meurig , Edwards Peter P. , Kuznetsov Vladimir L. 
Published: January 2008

AbstractThe years 2007 and 2008 mark the bi‐centenary of two brilliant discoveries by Sir Humphry Davy: the isolation of sodium and potassium (1807) and the subsequent first observation (1808) of the beautiful blue and bronze colours now known to be characteristic of the solvated electron1 in potassium–ammonia systems. In celebration of these dazzling discoveries, we reflect on Davy’s many extraodinary contributions to science, technology and poetry. Humphry Davy, a truly great man, of Cornish spirit, brought immeasurable benefits to humankind.
Synthesis and Redox Behavior of 1‐Azulenyl Sulfides and Efficient Synthesis of 1,1′‐Biazulenes
Authors: Shoji Taku , Higashi Junya , Ito Shunji , Toyota Kozo , Asao Toyonobu , Yasunami Masafumi , Fujimori Kunihide , Morita Noboru 
Published: January 2008

AbstractThe reaction of azulenes with several sulfoxides in the presence of acid anhydrides to afford the corresponding 1‐azulenylsulfonium and 1,3‐azulenediyldisulfonium ions is reported. The subsequent conversion of these ions in high yields into 1‐azulenyl methyl and phenyl sulfides and 1,3‐bis(methyl‐ and phenylthio)azulenes through treatment with diethylamine is also described. Reaction of the 1‐azulenyl sulfides with MCPBA afforded 1‐azulenyl sulfoxides, which were then efficiently transformed into 1,1′‐biazulene derivatives under acidic conditions. The redox properties of 1‐azulenyl methyl and phenyl sulfides, 1,3‐bis(methyl‐ and phenylthio)azulenes, and 1,1′‐biazulene derivatives bearing methylthio or phenylthio substituents on each azulene ring are reported based on the results of cyclic voltammetry experiments.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Skew‐Hadamard matrices of orders 436, 580, and 988 exist
Authors: Đoković Dragomir Ž. 
Published: January 2008

AbstractWe construct two difference families on each of the cyclic groups of order 109, 145, and 247, and use them to construct skew‐Hadamard matrices of orders 436, 580, and 988. Such difference families and matrices are constructed here for the first time. The matrices are constructed by using the Goethals‐Seidel array. © 2008 Wiley Periodicals, Inc. J Combin Designs 16: 493–498, 2008
Histological features of lymph node metastasis in patients with biliary tract cancer
Authors: Morimoto Haruki , Ajiki Tetsuo , Ueda Takashi , Sawa Hidehiro , Fujita Tsunenori , Matsumoto Ippei , Yasuda Takeo , Fujino Yasuhiro , Kuroda Yoshikazu , Ku Yonson 
Published: January 2008

AbstractBackground and ObjectivesThe presence of lymph node (LN) metastases is an important prognostic factor in patients with biliary cancers. The aim of this study was to characterize systematically the morphological features of metastatic LNs in biliary cancers.MethodsFour hundred ninety‐six LNs (including 112 para‐aortic LNs) dissected from 47 patients with biliary cancer were examined. The diameter of the long axis (size) and the percent metastatic area relative to whole‐node area were measured from histologic specimens.ResultsThe average size of metastatic LNs (9.5 mm) was significantly larger than those without metastasis (6.5 mm; P < 0.01). The optimum cut‐off size for positive LNs was >7.5 mm, but the sensitivity of this predictor of metastasis was low (60.8%). In general, metastatic area correlated significantly with the size of metastatic LNs (P = 0.023). Para‐aortic LNs contained metastasis in 7.1% of cases, and only 25% of para‐aortic LNs with a high ratio of metastatic area could be evaluated from preoperative CT scans.Although large LNs are highly suggestive of metastasis, poor detection of many small LNs with a low percentage of metastatic area can increase risk in patients with biliary tract cancer. J. Surg. Oncol. 2008;97:423–427. © 2008 Wiley‐Liss, Inc.Although large LNs are highly suggestive of metastasis, poor detection of many small LNs with a low percentage of metastatic area can increase risk in patients with biliary tract cancer. J. Surg. Oncol. © 2008 Wiley‐Liss, Inc.
Studying the photophysical properties of a polymerizable 1,8‐naphthalimide dye and its copolymer with styrene as potential fluorescent sensors for metal cations
Authors: Grabchev Ivo , Dumas Stephane , Chovelon Jean‐Marc 
Published: January 2008

AbstractThe photophysical characteristics of a polymerizable 1,8‐naphthalimide dye and its copolymer with styrene have been investigated. The functional properties of both low and high molecular weight fluorophores in the presence of different metal cations have been discussed with regard to their potential application as fluorosensors for the metal cations and protons. In acetonitrile solution the monomeric 1,8‐naphthalimide enhances its fluorescence emission in the presence of metal cations (Zn2+, Fe3+, Co2+, Pb2+, Cu2+, Ni2+, and Mn2+). In aqueous media the poly(St‐co‐MD) exhibits a selective response to Fe3+ cations. The monomeric and polymeric fluorophores also exhibit a considerable increase in their fluorescence intensity at acidic pH values (pH < 6) which suggest that they could be used as ON–OFF probes in analytical devices for signaling the presence of protons. Copyright © 2008 John Wiley & Sons, Ltd.
Magnetic hysteresis loop in antiferromagnetically coupled bilayer structures
Authors: Ma Yan , Du An 
Published: January 2008

AbstractThe hysteresis behavior of a bilayer film system, in which a hard ferromagnetic layer with larger anisotropy and spin‐3/2 couples with a soft ferromagnetic layer with smaller anisotropy and spin‐1 antiferromagnetically, is studied by using the Ising model and the linear cluster approach. We calculate the magnetic reversal of the soft magnetic layer at low field while keeping the saturated magnetization state of the hard magnetic layer unperturbed, and find a phenomenon of exchange bias. The influences of anisotropy, intralayer exchange in the soft magnetic layer, and the interlayer exchange on the coercivity and exchange bias in the bilayer film are discussed. It is found that increasing the interlayer coupling can enhance the exchange bias of the system, and the easy plane anisotropy in soft magnetic layers can induce the hysteresis loop moving towards positive field. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Lattice energy of zinc blende (AIIIBV and AIIBVI) solids
Authors: Verma A. S. , Sharma D. 
Published: January 2008

AbstractIn this paper we present an expression relating the lattice energy (U in kcal/mol) for the AIIIBV and AIIBVI semiconductors with the product of ionic charges (Z1Z2) and nearest‐neighbor distance d (Å). The lattice energy of these compounds exhibit a linear relationship when plotted on a log–log scale against the nearest‐neighbor distance d (Å), but fall on different straight lines according to the ionic charge product of the compounds. A fairly good agreement has been found between the observed and calculated values of the lattice energy for AIIIBV and AIIBVI semiconductors. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Strain solitary wave propagation in laser‐excited solids
Authors: Mirzade Fikret Kh. 
Published: January 2008

AbstractNonlinear dynamics of long 1D longitudinal waves in laser‐excited plates is investigated by taking into account the interaction of the longitudinal displacements with the temperature field and the field of concentration of non‐equilibrium (recombining) atomic point defects. The governing nonlinear equation is derived for describing the self‐consistent thermoelastic strain fields. It is found that the thermoelastic effect on the strain waves manifests itself in the appearance of dissipative terms, which describe the heat transfer and the thermoe lastic interaction caused by the strain‐induced heat releasedue to the recombination of atomic defects. The equation that describes the evolution of the amplitude of nonlinear localized waves with time in the single‐wave approximation is derived, and, on the basis of this equation, the damping increments of these waves are determined with allowance the dissipative losses. The effect of interaction of counterpropagating waves is considered. The influence of stress‐induced decay of defect complexes on the evolution of nonlinear dispersive strain waves is analyzed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bi‐stable behaviour in GaN‐based resonant tunnelling diode structures
Authors: Leconte S. , Golka S. , Pozzovivo G. , Strasser G. , Remmele T. , Albrecht M. , Monroy E. 
Published: January 2008

AbstractWe have investigated the vertical electronic transport in AlN/GaN/AlN double barrier structures grown by plasma‐assisted molecular‐beam epitaxy, with AlN barrier thickness of 0.5 nm and a GaN well thickness varying from 0.5 nm to 2 nm. Two different current levels were observed in different devices in all the samples, the highest one being attributed to leakage through dislocations, and the lower one to tunnelling transport through the barriers. In the sample with a well thickness of 0.5 nm, we observed a bi‐stable behaviour, with an apparent negative differential resistance in the current‐voltage characteristic when scanning the voltage from negative to positive bias. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Flexible parametric models for random‐effects distributions
Authors: Lee Katherine J. , Thompson Simon G. 
Published: January 2008

AbstractIt is commonly assumed that random effects in hierarchical models follow a normal distribution. This can be extremely restrictive in practice. We explore the use of more flexible alternatives for this assumption, namely the t distribution, and skew extensions to the normal and t distributions, implemented using Markov Chain Monte Carlo methods. Models are compared in terms of parameter estimates, deviance information criteria, and predictive distributions. These methods are applied to examples in meta‐analysis and health‐professional variation, where the distribution of the random effects is of direct interest. The results highlight the importance of allowing for potential skewing and heavy tails in random‐effects distributions, especially when estimating a predictive distribution. We describe the extension of these random‐effects models to the bivariate case, with application to a meta‐analysis examining the relationship between treatment effect and baseline response. We conclude that inferences regarding the random effects can crucially depend on the assumptions made and recommend using a distribution, such as those suggested here, which is more flexible than the normal. Copyright © 2007 John Wiley & Sons, Ltd.
The Relationship Between Wheat Flour and Starch Pasting Properties and Starch Hydrolysis: Effect of Non‐starch Polysaccharides in a Starch Gel System
Authors: Brennan Charles S. , Suter Manfred , Luethi Thomas , Matia‐Merino Lara , Qvortrup Jacqueline 
Published: January 2008

AbstractNon‐starch polysaccharides (NSPs) and celite (used as inert filler) were incorporated into wheat flour and wheat starch paste preparations at levels of 1, 2.5, and 5% in both addition and replacement modes. Pasting properties of gums were compared using a Rapid Visco Analyser. Use of guar gum and locust bean gum elevated the peak and final viscosities of the resulting pastes (when used in either addition or replacement modes), whereas arabic gum significantly reduced the peak and final viscosity properties of the pastes. Samples which comprised wheat starch yielded higher peak and final viscosity characteristics compared to wheat flour containing samples, however higher breakdown and setback values were observed for samples using wheat flour as a base compared to wheat starch. The firmness of the gels (as determined using a texture analyser) increased with the use of wheat starch compared to wheat flour. Little significant difference was observed between NSP used and mode of application (replacement or addition). In vitro starch degradation was conducted on the wheat flour gels. Guar gum and locust bean gum reduced the amount of starch degradation in these gels, whereas arabic gum and celite increased the amount of starch hydrolysis (or were similar to the control). The rate of starch hydrolysis appears to be related to the viscosity altering behaviour of the NSPs in a starch‐rich system. The results indicate that selection of NSPs is important as gum arabic has the potential to increase starch hydrolysis compared to the control.