bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of pH and ionic strength on Cu(II) biosorption by aerobic granular sludge and biosorption mechanism
Authors: Gai Li‐Hong , Wang Shu‐Guang , Gong Wen‐Xin , Liu Xian‐Wei , Gao Bao‐Yu , Zhang Hua‐Yong 
Published: March 2008

AbstractBACKGROUND: To elucidate the process and mechanism of Cu(II) biosorption onto aerobic granules, the influence of pH and ionic strength (IS) on the Cu(II) biosorption capacity and biosorption mechanism was studied.RESULTS: The biosorption of Cu(II) onto aerobic granules under different conditions of pH (3, 4 and 5), IS (0, 0.1 and 0.5 mol L−1) and Cu(II) concentration (25–250 mg L−1) was investigated. The correlation coefficients of the pseudo‐second‐order kinetic model were $R_{2}^{2} > 0.99$, while those of the Langmuir and Freundlich models were $R_{1}^{2} > 0.975$ and $R_{2}^{2} > 0.955$ respectively. The biosorption of Cu(II) increased with increasing pH, while the effect of IS on the biosorption was complicated, which could be explained by the competition among different metallic ions, colloidal chemistry theory or Derjaguin, Landau, verwey and Overbeek (DLVO) theory. About 70% of the solid phase Cu(II) was exchanged by Na(I), Ca(II) and Mg(II) released from the aerobic granules at pH 4 and 5. The results revealed that ion exchange is the most important biosorption mechanism but that other mechanisms also play a part.CONCLUSION: The sorption performance can be optimised by adjusting the pH and IS. Aerobic granules can be used as an alternative effective, economical and practical biosorbent for heavy metal removal. Copyright © 2008 Society of Chemical Industry
Selective enrichment of trace copper(II) from biological and natural water samples by SPE using ion‐imprinted polymer
Authors: Zhai Yunhui , Yang Dong , Chang Xijun , Liu Yongwen , He Qun 
Published: March 2008

AbstractA novel Cu(II)‐imprinted polymer sorbent was prepared by an ion‐imprinted polymer (IIP) technique using (2Z)‐N,N′‐bis(2‐aminoethylic)but‐2‐enediamide as the functional monomer and pentaerythritol triacylate as a crosslinker. IR, XPS, and elemental analysis techniques were used to confirm the obtained product. Subsequently, when this polymer was used as sorbent in SPE, it exhibited excellent selectivity for template ion from an aqueous solution. Quantitative extraction of Cu(II) was achieved in the pH range of 4–7. The time needed to extract each sample was less than 30 min by the batch method. The distribution ratio (D) values of IIP for Cu(II) were greatly larger than that for other ions. At optimal pH value, the maximum extraction capacity of IIP and nonimprinted polymer (NIP) was found to be 29.8 and 7.0 mg/g, respectively. The adsorption behavior of Cu(II) on the sorbents could be described by Langmuir adsorption isotherm equation. The feasible flow rate of Cu(II)‐containing solution for quantitative extraction onto the column packed with IIP was 1–4 mL/min, whereas for elution it was less than 1 mL/min. The developed method was successfully applied to the separation and enrichment of trace Cu(II) in biological and natural water samples with satisfactory results.
Double‐wall nanotube as vibrational system: Mathematical approach
Authors: Shubov Marianna A. , Rojas‐Arenaza Miriam 
Published: March 2008

AbstractIn this paper, we present a recently developed mathematical model for short double‐wall carbon nanotubes. The model is governed by a system of four hyperbolic equations representing the two Timoshenko beams coupled through the Van der Waals forces. The system is equipped with a four‐parameter family of the boundary conditions and can be reduced to an evolution equation. This equation defines a strongly continuous semi‐group. Spectral properties of the semi‐group generator are presented in the paper. We show that it is an unbounded non‐selfadjoint operator with compact resolvent. Moreover, this operator is a relatively compact perturbation of a certain selfadjoint operator. Copyright © 2008 John Wiley & Sons, Ltd.
Treatment of juvenile xanthogranuloma
Authors: Stover Daniel G. , Alapati Srilatha , Regueira Osvaldo , Turner Curtis , Whitlock James A. 
Published: March 2008

AbstractJuvenile xanthogranuloma (JXG) is generally a benign, self‐limited histiocytic disorder of the skin. We report two cases of multisystem JXG presenting with clinical features more commonly seen in Langerhans cell histiocytosis (LCH), including diabetes insipidus and lytic bony lesions. Histologically, the skin lesions demonstrated a histiocytic dermal infiltrate that stained for CD‐68, but S‐100 and CD1a stains were negative. Treatment according to LCH‐based chemotherapy regimens resulted in prompt resolution of symptoms. A literature review of multisystem JXG cases treated with chemotherapy suggests that symptomatic patients can successfully be treated with LCH‐based regimens that include both corticosteroids and vinca alkaloids. Pediatr Blood Cancer 2008;51:130–133. © 2008 Wiley‐Liss, Inc.
Management of women with psychosis during pregnancy
Authors: Howard Louise , Seneviratne Trudi 
Published: March 2008

AbstractIn the first of a series of reviews focusing on the management of women with psychiatric and neurological conditions during pregnancy, Dr Howard and Dr Seneviratne discuss the many issues surrounding the care of women with psychotic disorders during pregnancy and postpartum, including risks to the mother and fetus, use of antipsychotic medication and child protection issues. Copyright © 2008 Wiley Interface Ltd
Computational studies on the solvolysis of the chemical warfare agent VX
Authors: Daniel Kelly A. , Kopff Laura A. , Patterson Eric V. 
Published: March 2008

AbstractThe reaction of the chemical warfare agent VX with hydroxide and hydroperoxide has been studied using a combination of correlated molecular orbital and density functional theory. It is found that the alkaline hydrolysis leads to a mixture of neurotoxic and non‐toxic products while hydroperoxidolysis leads to exclusive formation of non‐toxic products. Natural bond orbital (NBO) analysis is used to rationalize the observation that hydroxide will attack opposite the alkoxide ligand, while hydroperoxide will attack opposite the thiolate. The current results are in good agreement with previous experimental and computational work and serve to clarify the mechanism for destruction of this highly potent nerve agent. Copyright © 2008 John Wiley & Sons, Ltd.
Effects of a herbal gel containing carvacrol and chalcones on alveolar bone resorption in rats on experimental periodontitis
Authors: Botelho Marco Antonio , Rao Vietla Satyanarayana , Montenegro Danusa , Bandeira Mary Anne Menezes , Fonseca Said Gonçalves Cruz , Nogueira Nadia Accioly Pinto , Ribeiro Ronaldo Albuquerque , Brito Gerly Anne Castro 
Published: March 2008

AbstractCarvacrol and dimeric chalcones are the respective bioactive components of Lippia sidoides and Myracrodruon urundeuva, popular medicinal plants of Northeastern Brazil with proven antimicrobial and antiinflammatory properties. Periodontal disease is associated with inflammation and microbiological proliferation, thus the study aimed to investigate the effect of a topical gel based on carvacrol and chalcones in the experimental periodontal disease (EPD) in rats. Animals were treated with carvacrol and/or chalcones gel, immediately after EPD induction, three times a day for 11 days. Appropriate controls were included in the study. Animals were weighed daily. They were killed on day 11, the mandibles dissected and alveolar bone loss was measured. The periodontium were examined at histopathology and the neutrophil influx into the gingiva was assayed using myeloperoxidase activity. The bacterial flora were assessed through culture of the gingival tissue. Alveolar bone loss was significantly (p < 0.05) inhibited by combined carvacrol and chalcones gel, compared with the vehicle and non‐treated groups. The treatment with the combined gel reduced tissue lesion at histopathology, decreased myeloperoxidase activity in gingival tissue and inhibited the growth of oral microorganisms as well as the weight loss. Carvacrol and chalcones combination gel has a beneficial effect upon EPD in this model. Copyright © 2008 John Wiley & Sons, Ltd.
Xα‐DVM investigation of double water molecule interactions with active sites of α‐ and β‐subunits of hemoglobin
Authors: Yuryeva Elmira I. 
Published: March 2008

AbstractIn this work, the results of Xα‐discrete variation method calculations of the electronic structure and interatomic parameters of chemical bonding between iron (II) and oxygen molecule with and without extra electrons and protons in active site (AS) of α‐ and β‐subunits of oxyhemoglobin are presented. The Skulachev model Skulachev, Sorosovskii obrazovatel'nyi zhurnal, 1998, 8, 2 of O2 molecule existing in respiration medium in the 2H2O form was used. The introduction of extra electrons does not change considerably the interaction of the iron atom with the O2 oxygen molecule, but strengthens the repulsion in the FeN bonds. In this case, the estimated effective charge of the iron atom is +1.8/1.5e for AS of α‐/β‐subunits of oxyhemoglobin, and the magnetic moment of iron atoms becomes zero. The deoxygenation effect of the AS of the α‐ and β‐subunits of oxyhemoglobin is due to the ability of extra protons to break down covalent attraction between the iron atom and the nearest oxygen atom and also to weakening of the repulsive component of the covalent FeN interactions. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Entanglement of angular momenta of atoms and molecules
Authors: Mishima K. , Yamashita K. 
Published: March 2008

AbstractIn this article, we investigate the entanglement degrees of angular momenta of atoms and molecules. We demonstrate theoretically and numerically the guidelines, how to prepare maximally entangled states and how the entanglement of the angular momenta changes by changing the quantum numbers of atoms and molecules. We show that the entanglement degree reduces to the Clebsch–Gordan coefficients frequently encountered in angular momentum theory. The maximally entangled states found in this manner are useful for quantum computers and quantum information science. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Structure‐hepatoprotective activity relationship study of sesquiterpene lactones: A QSAR analysis
Authors: Paukku Yuliya , Rasulev Bakhtiyor , Syrov Vladimir , Khushbaktova Zainab , Leszczynski Jerzy 
Published: March 2008

AbstractThis study has been carried out using quantitative structure‐activity relationship analysis (QSAR) for 22 sesquiterpene lactones to correlate and predict their hepatoprotective activity. Sesquiterpenoids, the largest class of terpenoids, are a widespread group of substances occurring in various plant organisms. QSAR analysis was carried out using methods such as genetic algorithm for variables selection among generated and calculated descriptors and multiple linear regression analysis. Quantum‐chemical calculations have been performed by density functional theory at B3LYP/6‐311G(d, p) level for evaluation of electronic properties using reference geometries optimized by semi‐empirical AM1 approach. Three models describing hepatoprotective activity values for series of sesquiterpene lactones are proposed. The obtained models are useful for description of sesquiterpene lactones hepatoprotective activity and can be used to estimate the hepatoprotective activity of new substituted sesquiterpene lactones. The models obtained in our study show not only statistical significance, but also good predictive ability. The estimated predictive ability (r) of these models lies within 0.942–0.969. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Coherent x‐ray diffraction measurements of Cu thin lines
Authors: Takahashi Yukio , Furukawa Hayato , Kubo Hideto , Yamauchi Kazuto , Nishino Yoshinori , Ishikawa Tetsuya , Matsubara Eiichiro 
Published: March 2008

Abstract1‐µm‐thick Cu thin lines with adjacent connections, which simulate via structures in large‐scale integration circuits, were fabricated on Si3N4 membranes by both electron‐beam evaporation and a focused ion beam for coherent x‐ray diffraction measurements. A direct current was applied to a Cu thin line to prepare an electromigration sample. In the scanning electron microscope image of the electromigration sample, a roughness of a few hundred nanometers was observed on the surface around the via structures. Coherent x‐ray diffraction patterns of both the thin line and electromigration samples were measured using synchrotron x‐rays at SPring‐8. Characteristic diffraction patterns resulting from both the shape of the Cu thin lines and the defects around the via structures formed by the application of the current were observed. Copyright © 2008 John Wiley & Sons, Ltd.
Practical guidelines for assessing power and false discovery rate for a fixed sample size in microarray experiments
Authors: Tong Tiejun , Zhao Hongyu 
Published: March 2008

AbstractOne major goal in microarray studies is to identify genes having different expression levels across different classes/conditions. In order to achieve this goal, a study needs to have an adequate sample size to ensure the desired power. Owing to the importance of this topic, a number of approaches to sample size calculation have been developed. However, due to the cost and/or experimental difficulties in obtaining sufficient biological materials, it might be difficult to attain the required sample size. In this article, we address more practical questions for assessing power and false discovery rate (FDR) for a fixed sample size. The relationships between power, sample size and FDR are explored. We also conduct simulations and a real data study to evaluate the proposed findings. Copyright © 2008 John Wiley & Sons, Ltd.
An imputation strategy for incomplete longitudinal ordinal data
Authors: Demirtas Hakan , Hedeker Donald 
Published: March 2008

AbstractA new quasi‐imputation strategy for correlated ordinal responses is proposed by borrowing ideas from random number generation. The essential idea is collapsing ordinal levels to binary ones and converting correlated binary outcomes to multivariate normal outcomes in a sensible way so that re‐conversion to the binary and then ordinal scale, after conducting multiple imputation, yields the original marginal distributions and correlations. This conversion process ensures that the correlations are transformed reasonably, which in turn allows us to take advantage of well‐developed imputation techniques for Gaussian outcomes. We use the phrase ‘quasi’ because the original observations are not guaranteed to be preserved. We present an application using a data set from psychiatric research. We conclude that the proposed method may be a promising tool for handling incomplete longitudinal or clustered ordinal outcomes. Copyright © 2008 John Wiley & Sons, Ltd.
Calibrating standards using chemical reagents for glass bead x‐ray fluorescence analyses of geochemical samples
Authors: Nakayama Kenichi , Nakamura Toshihiro 
Published: March 2008

AbstractCalibration standards for glass bead x‐ray fluorescence (XRF) analysis of geochemical samples are discussed in this article. Although rock references issued by geological organizations have often been applied to glass bead XRF, several problems remain: limited varieties and numbers, and uncertainty related to uncertified (recommended or preferred) values. Various geological references (e.g. rocks, sediments, and materials) having extensive elemental composition have often been applied for calibration. The XRF intensities must be corrected using an appropriate matrix‐correction method because the matrix effect resulting from the application of various references was not negligible. Attempts have been made to extend the calibration range by geological reference with such approaches as blending some references and adding chemical reagents to references. However, geological references for the calibrating standards should be used intact because the reliability of the certified values of references is lost. Synthesized calibrating standards with chemical reagents have constitutive properties which are superior to those of the rock references. Synthesized standards can ensure the traceability of the analytical procedure and the resultant accuracy and propriety of calibration curves. Reliable calibration curves are obtainable by designing such parameters as the number of plots, plotting arrangements, and calibrating ranges. Synthesized standards must be prepared by fitting the elemental composition to each geological sample. This discussion reviews calibration standards applying rock references or chemical reagents related to glass bead XRF. Copyright © 2008 John Wiley & Sons, Ltd.
Lifetime‐broadening‐suppressed XANES spectra of copper complexes
Authors: Hayashi Hisashi , Matsuo Shuji , Kurisaki Tsutomu , Kawamura Naomi 
Published: March 2008

AbstractLifetime‐broadening‐suppressed (LBS) Cu K‐XANES spectra of several Cu (II) complexes have been measured by partially fluorescent yield technique. The obtained spectra were compared with oscillator strength distributions calculated by discrete variational Xα method. It was demonstrated that LBS‐XANES spectra are sensitive to ligands, and hence are applicable as a helpful probe in coordination chemistry. Copyright © 2008 John Wiley & Sons, Ltd.
Powder briquette/x‐ray fluorescence analysis of major and minor elements in alkali‐washed fly ash of municipal solid waste
Authors: Ohbuchi Atsushi , Kitano Masaru , Nakamura Toshihiro 
Published: March 2008

AbstractX‐ray fluorescence (XRF) analyses of 13 major and 5 minor components in alkali‐washed fly ash of municipal solid waste were developed using powder briquette method. Fly ash samples were ground for 80 min using a ball mill to prepare reproducible powder briquette. The resultant particles had 12‐µm modal diameter and gave good reproducibility (3.2%). Calibration curves for analyses of 13 major and 5 minor elements required 16 reagents containing 18 analytes. They were ground for 20 min by ball milling after 80‐min mixing with a V‐type mixing machine or 2‐h manual mixing using an alumina mortar. Lower limits of detection corresponding to 3 times the standard deviation (n = 6) for blank measurements were: Na2O, 23 ppm; MgO, 22 ppm; Al2O3, 24 ppm; SiO2, 21 ppm; P2O5, 3.0 ppm; SO4, 3.1 ppm; Cl, 232 ppm; K2O, 51 ppm; CaO, 26 ppm; TiO2, 32 ppm; Cr, 6.3 ppm; MnO, 7.2 ppm; Fe2O3, 18 ppm; Ni, 5.3 ppm; Cu, 4.7 ppm; Zn, 5.4 ppm; Br, 4.7 ppm; and Pb, 4.6 ppm. This method was applied to analyses of 13 major and 5 minor elements in fly ash samples, which mainly consisted of Al2O3, SiO2, Cl, and CaO. Several thousand parts per million of Zn and Pb were included in most fly ash samples; Cl and Br were analyzed though their volatile characteristics. Copyright © 2008 John Wiley & Sons, Ltd.
Contribution of gut microbial lysine to liver and milk amino acids in lactating does
Authors: Abecia Leticia , Balcells Joaquím , Fondevila Manuel , Belenguer Alvaro , Holtrop Grietje , Lobley Gerald E. 
Published: March 2008

The contribution of microbial amino acids through caecotrophy to tissue protein metabolism was investigated in lactating does. Attempts were made to vary microbial supply through a dietary antibiotic, Zn bacitracin, and to vary tissue demand through manipulation of litter size. Three groups of eight New Zealand does were fed different experimental diets from day 28 of pregnancy to day 26 of lactation. The control group received the basal diet formulated to meet requirements with grass hay, wheat, soyabean meal and barley grain. The second (no antibiotic) group and the third (bacitracin; BAC) group ingested the basal diet supplemented with ammonium sulfate (5 g/kg), initially unlabelled (day 1 to day 8) then labelled with15N (day 9 to day 30), while the BAC diet was also supplemented throughout with antibiotic (Zn bacitracin; 100 mg/kg). From just after birth each group of does was subdivided into two groups, each of four females, with the litter size either five (LS5) or nine (LS9) pups. The15N enrichment in liver, milk and caecal bacteria amino acids was determined by GC-combustion-isotope ratio MS. All amino acids in bacterial protein were enriched with the (15NH4)2SO4treatment, with lysine15N enrichment significantly greater in caecal bacteria (0·23 (se0·0063) atom % excess (ape)) than in liver (0·04 (se0·0004) ape) or milk protein (0·05 (se0·0018) ape), confirming the double origin (bacterial and dietary) of tissue lysine. The contribution of microbes to tissue lysine was 0·23 (se0·006) when milk protein was used as reference.
Extreme values for Benedicks–Carleson quadratic maps
Authors: MOREIRA FREITAS ANA CRISTINA , FREITAS JORGE MILHAZES 
Published: March 2008

AbstractWe consider the quadratic family of maps given by fa(x)=1−ax2 with x∈[−1,1], where a is a Benedicks–Carleson parameter. For each of these chaotic dynamical systems we study the extreme value distribution of the stationary stochastic processes X0,X1,… , given by Xn=fan, for every integer n≥0, where each random variable Xn is distributed according to the unique absolutely continuous, invariant probability of fa. Using techniques developed by Benedicks and Carleson, we show that the limiting distribution of Mn=max {X0,…,Xn−1} is the same as that which would apply if the sequence X0,X1,… was independent and identically distributed. This result allows us to conclude that the asymptotic distribution of Mn is of type III (Weibull).
Preparation, Characterization and Refolding in Vitro of a Recombinant Human Cyclophilin A Mutant: Effect of a Single Pro/Ser Substitution on Cyclophilin A Structure and Properties
Authors: Xu Li‐Ren , Yan Xiao , Luo Man , Guan Yi‐Xin , Yao Shan‐Jing 
Published: March 2008

AbstractA recombinant cyclophilin A (CypA) mutant, which carries a serine instead of proline at sequence 16, was prepared for structural and functional assessment for human CypA. Soluble expression of the recombinant CypA mutant in E. coli was obtained under 30 °C, 180 rpm culture condition after being induced by IPTG. Ion exchange chromatography was used to purify the CypA mutant in a single step, and a high activity recovery of target protein with a high purity was achieved. Peptide fragments produced by trypsin proteolysis were applied to MALDI‐TOF‐MS, and searching results from the NCBI protein databank confirmed the protein attribution as well as the mutation sequence. Peptidyl‐prolyl cis‐ trans isomerase activity was assayed for the CypA mutant using tetrapeptide substrate Suc‐Ala‐Ala‐Pro‐Phe‐ p‐nitroanilide, and the calculated kcat/ Km value was 1.5 × 106 M−1 s−1 at 10 °C, which was 10‐fold lower than the previously reported constant for wild‐type CypA. An Eyring plot was also carried out. Inhibition by cyclosporine A demonstrated that the IC50 value was 26.5 nM. Meanwhile the expected enhancement of intrinsic tryptophan fluorescence was quenched by the mutation. The effect of CypA mutant on accelerating protein refolding in vitro was investigated in ribonuclease A refolding process, and it was found that 10% slow phase could be catalyzed by CypA. The protein was subject to urea and GdmCl denaturation, where both activity and fluorescence served as structural probes. Activity recovery indicated this CypA mutant was extremely sensitive to GdmCl and the susceptibility to urea was increased. Low pH could also destabilize CypA. Furthermore the refolding of this CypA mutant itself was studied. Although the activity yield was nearly unchanged, the former proposed folding/assembly pathway might be altered. Fluorescence chart also demonstrated that the folding time was extended, and fast‐folding and slow‐folding analysis indicated the slow‐folding rate constant presented a concentration dependence property denoting the autocatalysis of the foldase.