bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies of substrate specificities of lipases from different sources
Authors: Song Xin , Qi Xiaoyu , Hao Bin , Qu Yinbo
Published: August 2008

Although lipases are widely applied in a wide variety of reactions, available information on the factors that are responsible for the substrate specificities of lipases from different sources is scarce. In this paper, nine lipase‐producing microorganism strains were isolated from oil‐containing samples. The properties of these enzymes, including pH optima, temperature optima, thermal stability, and pH stability, vary significantly with the different sources from which these lipases were isolated. The substrate specificities of the nine lipases, including fatty acid and positional specificities, were also studied. The fatty acid specificities of the nine lipases were observably different toward 15 substrates with different carbon chain lengths, different saturation degrees and different side chains. The lipases from S3 Penicillium citrinum (PCL), MJ1 Aspergillus niger (ANL), MJ2 Aspergillus oryzae (AOL), YM Bacillus coughing (BCL), S9 Geotrichum candidum (GCL), and S11 Candida lypolytica (CLL) showed the strongest specificities to short‐chain esters, and the other lipases showed strong selectivity for medium‐ or long‐chain and branched esters. The positional specificities were examined by analyzing the hydrolytic products of triolein catalyzed by the nine lipases, using TLC. The lipases can be mainly classified into two groups by their specificities for the ester bond at position 2 of triglycerides; one group can selectively hydrolyze the ester bond at position 2 of the triglycerides, the other group cannot. All these nine lipases were divided into four groups by hierarchical clustering analysis on the basis of the results of fatty acid and positional specificities.
Synthesis of Alkaloids of Galipea officinalis by Alkylation of an α‐Amino Nitrile
Authors: Shahane Saurabh , Louafi Fadila , Moreau Julie , Hurvois Jean‐Pierre , Renaud Jean‐Luc , van de Weghe Pierre , Roisnel Thierry
Published: August 2008

A new synthetic approach directed towards the synthesis of naturally occurring 2‐alkyl‐tetrahydroquinolines is described. The C–C bonds in the α position relative to the nitrogen atom were formed by the reversal of the polarity of the C=N bond of α‐amino nitrile 6, which was prepared electrochemically from 1‐(phenylethyl)‐tetrahydroquinoline. A NaBH4‐mediated reductive decyanation process furnished benzylic amines 16a–d as mixtures of diastereomers (50–60 % de). The catalytic hydrogenolysis of these amines was performed in the presence of Pearlman's catalyst to give the tetrahydroquinolines 17a–d in yields ranging from 70 % to 95 %. Methylation of the free nitrogen atom afforded the title compounds 1–4 in 70–90 % yields.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Electroanalytical Determination of Promethazine Hydrochloride in Pharmaceutical Formulations on Highly Boron‐Doped Diamond Electrodes Using Square‐Wave Adsorptive Voltammetry
Authors: Ribeiro Francisco Wirley P. , Cardoso Amanda S. , Portela Rafael R. , Lima Janete E. S. , Machado Sergio A. S. , de Lima‐Neto Pedro , De Souza Djenaine , Correia Adriana N.
Published: August 2008

The electrochemical oxidation of promethazine hydrochloride was made on highly boron‐doped diamond electrodes. Cyclic voltammetry experiments showed that the oxidation mechanisms involved the formation of an adsorbed product that is more readily oxidized, producing a new peak with lower potential values whose intensity can be increased by applying the accumulation potential for given times. The parameters were optimized and the highest current intensities were obtained by applying +0.78 V for 30 seconds. The square‐wave adsorptive voltammetry results obtained in BR buffer showed two well‐defined peaks, dependent on the pH and on the voltammetric parameters. The best responses were obtained at pH 4.0, frequency of 50 s−1, step of 2 mV, and amplitude of 50 mV. Under these conditions, linear responses were obtained for concentrations from 5.96×10−7 to 4.76×10−6 mol L−1, and calculated detection limits of 2.66×10−8 mol L−1 (8.51 μg L−1) for peak 1 and of 4.61×10−8 mol L−1 (14.77 μg L−1) for peak 2. The precision and accuracy were evaluated by repeatability and reproducibility experiments, which yielded values of less than 5.00% for both voltammetric peaks. The applicability of this procedure was tested on commercial formulations of promethazine hydrochloride by observing the stability, specificity, recovery and precision of the procedure in complex samples. All results obtained were compared to recommended procedure by British Pharmacopeia. The voltammetric results indicate that the proposed procedure is stable and sensitive, with good reproducibility even when the accumulation steps involve short times. It is therefore very suitable for the development of the electroanalytical procedure, providing adequate sensitivity and a reliable method.
Fabrication of a Sensitive Impedance Biosensor of DNA Hybridization Based on Gold Nanoparticles Modified Gold Electrode
Authors: Zhang Keying , Ma Haiyan , Zhang Liping , Zhang Yuzhong
Published: August 2008

In this work, we report on the preparation of a simple, sensitive DNA impedance sensor. Firstly gold nanoparticles were electrodeposited on the surface of a gold electrode, and then probe DNA was immobilized on the surface of gold nanoparticles through a 5′‐thiol‐linker. Electrochemical impedance spectroscopy (EIS) was used to investigate probe DNA immobilization and hybridization. Compared to the bare gold electrode, the gold nanoparticles modified electrode could improve the density of probe DNA attachment and the sensitivity of DNA sensor greatly. The difference of electron transfer resistance (ΔRet) was linear with the logarithm of complementary oligonucleotides sequence concentrations in the range of 2.0×10−12 to 9.0×10−8 M, and the detection limit was 6.7×10−13 M. In addition, the DNA sensor showed a fairly good reproducibility and stability during repeated regeneration and hybridization cycles.
The Influence of the Electrodeposition Conditions on the Electroanalytical Performance of the Bismuth Film Electrode for Lead Determination
Authors: Nunes Luiza M. S. , Faria Ronaldo C.
Published: August 2008

The bismuth film is a great promise as a suitable material to replace the mercury electrodes due to its low toxicity and good cathodic potential range. This work studies the influence of the electrodeposition conditions in the morphology and electroanalytical performance of the bismuth film electrodeposited onto copper electrode. The bismuth films were obtained in nitric or hydrochloric acid solutions with and without the presence of sodium citrate. The films were characterized by field emission scanning electron microscopy (FE‐SEM) and scanning electron microscopy with energy dispersive X‐ray spectrometry (SEM‐EDX). The microscopic analysis of the bismuth film obtained in HCl solution with sodium citrate (BIFE‐Cit) showed more homogeneous structure with higher content of bismuth than the film obtained in HCl only (BiFE‐HCl). The BiFE‐Cit exhibited a better analytical performance for lead with good adherence to the copper substrate.
Development of a Creatinine Sensor Based on a Molecularly Imprinted Polymer‐Modified Sol‐Gel Film on Graphite Electrode
Authors: Patel Amit Kumar , Sharma Piyush Sindhu , Prasad Bhim Bali
Published: August 2008

An electrochemical creatinine sensor based on a molecularly imprinted polymer (MIP)‐modified sol‐gel film on graphite electrode was developed. The surface coating of MIP over sol‐gel was advantageous to obtain a porous film with outwardly exposed MIP cavities for unhindered selective rebinding of creatinine from aqueous and biological samples. A fast differential pulse, cathodic stripping voltammetric response of creatinine can be obtained after being preanodized the sensor in neutral medium containing appropriate amount of creatinine at +1.8 V versus SCE for 120 s. A linear response over creatinine concentration in the range of 1.23 to 100 μg mL−1 was exhibited with a detection limit of 0.37 μg mL−1 (S/N=3).
Study on the Indirect Electrochemical Detection of Ammonium Ion with In Situ Electrogenerated Hypobromous Acid
Authors: Takahashi Miki , Nakamura Kenta , Jin Jiye
Published: August 2008

The electrochemical oxidation of bromide in the presence of ammonium ion (NH$\rm{ {_{4}^{+}}}$) was studied by cyclic voltammetry and UV‐vis spectroscopy. The experimental results suggested that the anodically generated bromine (Br2) would be hydrolyzed to hypobromous acid (HBrO) at the pH range of 5–7 and was further disproportionate to hypobromite anion (BrO−) when pH was larger than 7. Both HBrO and BrO− were confirmed to be participated in the following homogeneous chemical reaction with the coexisted ammonium ion. However, HBrO is electroactive whereas BrO‐ is electroinactive at carbon electrode. Based upon the reaction of HBrO with NH$\rm{ {_{4}^{+}}}$, an indirect electrochemical method was proposed for determination of NH$\rm{ {_{4}^{+}}}$ with dual‐electrode configuration in phosphate buffer solution (pH 7), where HBrO was produced at a generator electrode and the excess HBrO was subsequently detected at a collector electrode after a reaction with NH$\rm{ {_{4}^{+}}}$ in a batch solution or in a micro flow injection analytical (micro‐FIA) system by using an interdigitated array (IDA) Pt microelectrode and a carbon film ring‐disk electrode (CFRDE), respectively. The decreasing of reduction current at the collector electrode was proportional to the concentration NH$\rm{ {_{4}^{+}}}$ in both systems, with the detection limit below 3.0 μM. This approach shows the advantage of highly selectivity even in presence of a large amount of coexisted cations, and was successfully applied for the determination of NH$\rm{ {_{4}^{+}}}$ in environmental water samples.
Clonal expansions of 6‐thioguanine resistant T lymphocytes in the blood and tumor of melanoma patients
Authors: Albertini Mark R. , Macklin Michael D. , Zuleger Cindy L. , Newton Michael A. , Judice Stephen A. , Albertini Richard J.
Published: August 2008

The identification of specific lymphocyte populations that mediate tumor immune responses is required for elucidating the mechanisms underlying these responses and facilitating therapeutic interventions in humans with cancer. To this end, mutant hypoxanthine‐guanine phosphoribosyltransferase (HPRT) deficient (HPRT‐) T‐cells were used as probes to detect T‐cell clonal amplifications and trafficking in vivo in patients with advanced melanoma. Mutant T‐cells from peripheral blood were obtained as clonal isolates or in mass cultures in the presence of 6‐thioguanine (TG) selection and from tumor‐bearing lymph nodes (LNs) or metastatic melanoma tissues by TG‐selected mass cultures. Nonmutant (wild‐type) cells were obtained from all sites by analogous means, but without TG selection. cDNA sequences of the T‐cell receptor (TCR) beta chains (TCR‐β), determined directly (clonal isolates) or following insertion into plasmids (mass cultures), were used as unambiguous biomarkers of in vivo clonality of mature T‐cell clones. Clonal amplifications, identified as repetitive TCR‐β V‐region, complementarity determining region 3 (CDR3), and J‐region gene sequences, were demonstrated at all sites studied, that is, peripheral blood, LNs, and metastatic tumors. Amplifications were significantly enriched among the mutant compared with the wild‐type T‐cell fractions. Importantly, T‐cell trafficking was manifested by identical TCR‐β cDNA sequences, including the hypervariable CDR3 motifs, being found in both blood and tissues in individual patients. The findings described herein indicate that the mutant T‐cell fractions from melanoma patients are enriched for proliferating T‐cells that infiltrate the tumor, making them candidates for investigations of potentially protective immunological responses. Environ. Mol. Mutagen., 2008. Published 2008 Wiley‐Liss, Inc.
Antimicrobial effect of vapours of terpineol, (R)‐(–)‐linalool, carvacrol, (S)‐(–)‐perillaldehyde and 1,8‐cineole on airborne microbes using a room diffuser
Authors: Krist Sabine , Sato Kei , Glasl Sabine , Hoeferl Martina , Saukel Johannes
Published: August 2008

In this study the antimicrobial activities of five volatiles, which represent main compounds of several essential oils, were tested. Terpineol, (R)‐(–)‐linalool, carvacrol, (S)‐(–)‐perillaldehyde and 1,8‐cineole were evaluated for their influence on airborne microbes when vaporized with a room diffuser. In the present investigation terpineol and (S)‐(–)‐perillaldehyde showed the highest antimicrobial activities. The average reduction of the germ count was 59.4% and 42.3%, respectively, after 5 h of spreading in a testing room. Carvacrol (average germ reduction 37.5%) and (R)‐(–)‐linalool (29.7%) showed lower results. For 1,8‐cineole only, no unambiguous antimicrobial effect was detectable. It has to be considered that the amounts of vapour spread during 5 h of testing time were different, depending on the volatility of the scent used. Nevertheless, four of the investigated volatiles showed satisfying antimicrobial action against airborne microbes. Copyright © 2008 John Wiley & Sons, Ltd.
Correlation of environmental and cultural chronology in New Caledonia
Authors: Carson Mike T.
Published: August 2008

A case study in New Caledonia explores the changes in the natural and cultural setting at the end of the Lapita period in the first millennium B.C. After the mid‐Holocene highstand, sea level fell about 1.5 m, thereby enlarging coastal plains, altering previous mangrove and marshy settings, and transforming nearshore marine environments. Many of these changes occurred gradually over several centuries, but the termination of finely decorated Lapita pottery coincided with the first signs of loss of coastal habitat optimal for marine‐based horticulturalists in the first millennium B.C. Organized village compounds and extensively cultivated landscapes emerged much later, in the first millennium A.D. The results suggest that, although the Lapita phenomenon represents the founding ancestry of Oceanic societies, it also represents the end of an era and way of life that eventually could not be maintained in a changing world. © 2008 Wiley Periodicals, Inc.
A micromorphological analysis of stratigraphic integrity and site formation at Cactus Hill, an Early Paleoindian and hypothesized pre‐Clovis occupation in south‐central Virginia, USA
Authors: Macphail1 Richard I. , McAvoy Joseph M.
Published: August 2008

Twenty thin sections were studied from Cactus Hill, a ca. 20 ka stratified sand dune site in Virginia, USA, with a Clovis and hypothesized pre‐Clovis component. The high‐resolution soil micromorphology investigation focused on testing the integrity of Clovis and pre‐Clovis stratigraphy from one location where there is a high density of artifacts. Site formation processes were dominated by eolian (dune) sand formation. There was also ephemeral topsoil development and associated occupation, along with their penecontemporaneous disturbance and dispersal by scavenging animals (assumed) and localized down‐working by small invertebrate mesofauna (as evidenced by aggregates of fine phytolith‐rich humic soil and fine soil‐coated charcoal fragments). Partial erosion of these occupation soils (deflation?) was followed by successive sand burial. Post‐depositional processes affecting these sand‐buried occupations involved only small‐scale bioturbation and overprinting of clay lamellae, suggesting site stratigraphy has been stable for a long time. Soil micromorphological analysis has defined a difference between occupational units (pre‐Clovis and Clovis) and sterile units found between these units as well as above and below. In summary, according to this analysis, the site appears intact with only minor disturbances affecting the long‐term integrity of the stratigraphy. © 2008 Wiley Periodicals, Inc.
The effects of cigarette smoking and abstinence on auditory verbal learning
Authors: Soar Kirstie , Dawkins Lynne , Begum Husna , Parrott Andrew C.
Published: August 2008

Smoking has been associated with both enhanced and impaired cognitive performance; across a variety of domains, but there is limited evidence demonstrating the effects on verbal learning. The current study assessed the effect of smoking and abstinence on verbal learning, immediate memory and retention using the Auditory Verbal Learning Test (AVLT). Three groups: 20 smokers, 20 abstaining smokers and 20 non‐smoking adults were assessed on the AVLT on two occasions. At session one, abstaining smokers refrained from smoking for 12 h (pre‐cigarette), whilst smokers had continued to smoke to satiety. Session two commenced after a 15‐min break when both smoking groups were instructed to smoke a cigarette, followed by administration of the second version of the AVLT (post‐cigarette). Abstaining smokers showed significant deficits in learning compared to smokers during the pre‐cigarette session. Following re‐initiation of smoking in the abstaining smokers, these learning decrements were no longer evident. There were trends towards significant group findings in immediate memory and retention during the pre‐cigarette session, which again were no longer evident in the post‐cigarette session. These findings provide further evidence that smoking abstinence affects verbal learning and furthermore smoking simply restores cognitive performance to pre‐abstinence levels. Copyright © 2008 John Wiley & Sons, Ltd.
Variation in lung cancer risk by smoky coal subtype in Xuanwei, China
Authors: Lan Qing , He Xingzhou , Shen Min , Tian Linwei , Liu Larry Z. , Lai Hong , Chen Wei , Berndt Sonja I. , Hosgood Howard Dean , Lee Kyoung‐Mu , Zheng Tongzhang , Blair Aaron , Chapman Robert S.
Published: August 2008

Lung cancer rates in Xuanwei County have been among the highest in China for both males and females and have been causally associated with exposure to indoor smoky (bituminous) coal emissions that contain very high levels of polycyclic aromatic hydrocarbons. There are numerous coal mines across the County. Although lung cancer risk is strongly associated with the use of smoky coal as a whole, variation in risk by smoky coal subtype has not been characterized as yet. We conducted a population‐based case–control study of 498 lung cancer cases and 498 controls, individually matched to case subjects on age (±2 years) and sex to examine risk by coal subtype. Odds ratios (ORs) and 95% confidence intervals (CIs) for coal subtype were calculated by conditional logistic regression, adjusting for potential confounders. Overall, smoky coal use was positively and statistically significantly associated with lung cancer risk, when compared with the use of smokeless coal or wood (OR = 7.7, 95% CI = 4.5–13.3). Furthermore, there was a marked heterogeneity in risk estimates for specific subtypes of smoky coal (test for heterogeneity: p = 5.17 × 10−10). Estimates were highest for coal of the Laibin (OR = 24.8, 95% CI = 12.4–49.6) and Longtan (OR = 11.6, 95% CI = 5.0–27.2) coal types and lower for coal from other subtypes. These findings strongly suggest that in Xuanwei and elsewhere, the carcinogenic potential of coal combustion products can exhibit substantial local variation by specific coal source. Published 2008 Wiley‐Liss, Inc.
ApoG2, a novel inhibitor of antiapoptotic Bcl‐2 family proteins, induces apoptosis and suppresses tumor growth in nasopharyngeal carcinoma xenografts
Authors: Hu Zhe‐Yu , Zhu Xiao‐Feng , Zhong Zhen‐Dong , Sun Jian , Wang Jing , Yang Dajun , Zeng Yi‐Xin
Published: August 2008

Nasopharyngeal carcinoma (NPC) is a common malignant tumor in South China. It has been reported that overexpression of antiapoptotic Bcl‐2 family proteins in NPC has caused the lack of long‐term efficacy of conventional therapies. Apogossypolone (ApoG2), a novel small‐molecule inhibitor of antiapoptotic Bcl‐2 family proteins, has been discovered as the optimized derivative of gossypol. In this study, we found that in NPC cells, ApoG2 totally blocked the antiapoptotic function of Bcl‐2 family proteins without affecting the expression levels of these proteins. ApoG2 selectively inhibited proliferation of 3 NPC cell lines (C666‐1, CNE‐1 and CNE‐2) that highly expressed the antiapoptotic Bcl‐2 proteins. This inhibitory activity was associated with release of cytochrome c, activation of caspase‐9 and caspase‐3 and apoptosis of sensitive NPC cells. However, ApoG2 had no obvious inhibitory effect on NPC cell line HONE‐1, which expressed antiapoptotic Bcl‐2 and Bcl‐xL at a low level. We further found that ApoG2 effectively suppressed tumor growth of NPC xenografts in nude mice and enhanced the antitumor effect of CDDP (cisplatin) on NPC cells in vitro and in vivo. Immunohistochemical results showed that the expression of CD31 decreased after ApoG2 treatment, which suggested inhibition of angiogenesis in NPC xenografts. Our findings strongly suggest that ApoG2 may serve as a novel inhibitor of Bcl‐2 family proteins and, by targeting these proteins, may become a promising drug for the treatment of NPC. © 2008 Wiley‐Liss, Inc.
Rosiglitazone, a PPAR gamma agonist: Potent promoter of hydroxybutyl(butyl)nitrosamine‐induced urinary bladder cancers
Authors: Lubet Ronald A. , Fischer Susan M. , Steele Vernon E. , Juliana M. Margaret , Desmond Renee' , Grubbs Clinton J.
Published: August 2008

In an initial study to determine if rosiglitazone had chemopreventive activity, Fischer‐344 female rats were administered twice weekly doses of hydroxybutyl(butyl)nitrosamine (OH‐BBN), a urinary bladder specific carcinogen, for 8 weeks. Two weeks following the last dose of OH‐BBN, rats were administered rosiglitazone (50 mg/kg BW) daily by gavage for the remainder of the study (7 months). Only 57% of OH‐BBN‐treated animals developed palpable urinary bladder cancers during the course of the study, while all of the OH‐BBN plus rosiglitazone treated rats developed large cancers (p < 0.01). Surprisingly, examination for PPAR gamma by immunohistochemistry in the urinary bladders of rats showed that while untreated bladder urothelium and preneoplastic lesions clearly expressed PPAR gamma, frank carcinomas exhibited significantly lower levels. This was confirmed by employing microarray studies of the same samples. In additional studies, lower doses of rosiglitazone (10, 2 and 0.4 mg/kg BW/day) were administered. The 10 mg/kg BW/day dose greatly enhanced bladder cancer incidence (p < 0.01). The dose of 2 mg/kg BW/day, which is roughly equivalent to a standard human dose, also significantly increased bladder cancer incidence (controls, 48%; rosiglitazone‐treated, 84%). The lowest dose did not significantly increase tumor incidence (rosiglitazone at 0.4 mg/kg BW/day, 64%) or tumor weight in the rats, although there was a trend in that direction. Rosiglitazone alone (10 mg/kg BW/day) given in the absence of OH‐BBN did not result in bladder cancer formation when given for 10 months. In summary, rosiglitazone over a wide dose range enhanced urinary bladder carcinogenesis in the OH‐BBN model in rats. Published 2008 Wiley‐Liss, Inc.
In vitro cytotoxicity of maxillofacial silicone elastomers: Effect of accelerated aging
Authors: Bal Bilge Turhan , Yılmaz Handan , Aydın Cemal , Karakoca Seçil , Yılmaz Şükran
Published: August 2008

The purpose of this in vitro study was to evaluate the cytotoxicity of three maxillofacial silicone elastomers at 24, 48, and 72 h on L‐929 cells and to determine the effect of accelerated aging on the cytotoxicity of these silicone elastomers. Disc‐shaped test samples of maxillofacial silicone elastomers (Cosmesil, Episil, Multisil) were fabricated according to manufacturers' instructions under aseptic conditions. Samples were then divided into three groups: (1) not aged; (2) aged for 150 h with an accelerated weathering tester; and (3) aged for 300 h. Then the samples were placed in Dulbecco's Modified Eagle Medium/Ham's F12 (DMEM/F12) for 24, 48, and 72 h. After the incubation periods, cytotoxicity of the extracts to cultured fibroblasts (L‐929) was measured by MTT assay. The degree of cytotoxicity of each sample was determined according to the reference value represented by the cells with a control (culture without sample). Statistical significance was determined by repeated measurement ANOVA (p < 0.01) followed by Duncan's test (p < 0.05). All test materials in each group demonstrated high survival rates in MTT assay (Episil; 93.84%, Multisil; 88.30%, Cosmesil; 87.50%, respectively); however, in all groups, Episil material demonstrated significantly higher cell survival rate after each of the experimental incubation periods (p < 0.05). Accelerated aging for 150 and 300 h had no significant effect on the biocompatibility of maxillofacial silicone elastomers tested (p > 0.05). © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Rituximab as an adjunct to plasma exchange in TTP: A report of 12 cases and review of literature
Authors: Jasti Sushama , Coyle Thomas , Gentile Teresa , Rosales Lawrence , Poiesz Bernard
Published: August 2008

Idiopathic thrombotic thrombocytopenic purpura (TTP) is caused by the production of autoantibodies against the Von Willebrand factor cleaving enzyme. This provides a rationale for the use of rituximab in this disease. We report a retrospective review of 12 patients treated with rituximab for TTP refractory to plasma exchange. Eleven patients were treated during initial presentation, and one patient was treated for recurrent relapse. Ten patients responded to treatment. Median time to response after first dose of rituximab was 10 days (5–32). Of the 11 patients treated during initial presentation, nine remain free of relapse after a median follow‐up of 57+ months (1+–79+). Two patients died during initial treatment. One patient was lost to follow‐up 1 month after achieving complete response. The patient treated for recurrent disease during second relapse remained disease free for 2years, relapsed and was treated again with rituximab, and was in remission for 22 months. She relapsed again, was retreated, and has now been in remission for 21+ months. We conclude that rituximab is an useful addition to plasma exchange treatment in TTP, but its exact role and dosing need to be verified in prospective studies. J. Clin. Apheresis, 2008. © 2008 Wiley‐Liss, Inc.
Combination of Cobe AutoPBSC and Gambro Elutra as a platform for monocyte enrichment in dendritic cell (DC) therapy: Clinical study
Authors: Chen Ying , Hoecker Paul , Zeng Jia , Dettke Markus
Published: August 2008

Monocytes are a common source for generating dendritic cells (DCs). The aim of the present study was to evaluate the efficiency of a platform for monocyte collection and enrichment in a clinical setting. The platform was based on the combination of two semiautomated devices; the Cobe Spectra Auto PBSC for mononuclear cells (MNC) collection followed by counterflow elutriation for monocyte enrichment (Gambro BCT Elutra). Twenty‐four patients with various types of epithelial cancer participated in the study. MNC collections were first performed as large volume leukapheresis (LVL). Subsequently, MNC products were processed with an elutriation system for monocyte isolation. LVL resulted in the collection of MNC at a median of 8.1 × 109 cells, containing of 31.4% monocytes. A similar efficacy was also shown in patients with lower peripheral blood counts. Elutriation of the MNC product with the Cobe Elutra device resulted in the enrichment of monocytes at a median of 2.7 × 109 cells, with a recovery of 80.2% and a purity of 90.7%. These monocytes were then successfully developed into DCs for clinical therapy after in vitro manipulation. These data suggest that the combination of the Cobe Spectra Auto PBSC and the Gambro BCT Elutra is an effective platform for monocyte enrichment in clinical practice according to GCP standards and GMP guidelines, and can be easily implemented in the clinical routine under current DC protocols. J. Clin. Apheresis, 2008. © 2008 Wiley‐Liss, Inc.
Fermentation of cheese whey powder solution to ethanol in a packed‐column bioreactor: effects of feed sugar concentration
Authors: Ozmihci Serpil , Kargi Fikret
Published: August 2008

BACKGROUND: Cheese whey powder (CWP) is a concentrated source of lactose and other essential nutrients for ethanol fermentation. CWP solution containing different concentrations of total sugar was fermented to ethanol in an up‐flow packed‐column bioreactor (PCBR) at a constant hydraulic residence time (HRT) of 50 h. Total sugar concentration in the feed was varied between 50 and 200 g L−1 and a pure culture of Kluyveromyces marxianus was used for ethanol fermentation of lactose. Variations of ethanol and sugar concentrations with the height of the column and with the feed sugar concentration were determined.

RESULTS: Ethanol concentration increased and total sugar decreased with the column height for all feed sugar contents. The highest effluent ethanol concentration (22.5 g L−1) and ethanol formation rate were obtained with feed sugar content of 100 g L−1. Percentage sugar utilization decreased with increasing feed sugar content above 100 g L−1 yielding lower ethanol contents in the effluent. The highest ethanol yield coefficient (0.52 gE g−1S) was obtained with a feed sugar content of 50 g L−1. Biomass concentration also decreased with column height, yielding low ethanol formation in the upper section of the column.

CONCLUSION: The packed column bioreactor was found to be effective for ethanol fermentation from CWP solution. The optimum feed sugar content maximizing the effluent ethanol and the specific rate of ethanol formation was found to be 100 g L−1. High sugar content above 100 g L−1 resulted in low ethanol productivities due to high maintenance requirements. Copyright © 2008 Society of Chemical Industry
Bioconversion of linoleic acid to conjugated linoleic acid by Lactobacillus reuteri under different growth conditions
Authors: Hernandez‐Mendoza Adrian , Lopez‐Hernandez Arnoldo , Hill Charles G , Garcia Hugo S
Published: August 2008

BACKGROUND: Lactobacillus reuteri was grown in De Man/Rogosa/Sharpe (MRS) broth (initial pH 6.5) supplemented with free linoleic acid (LA) at different concentrations (5, 10, 20 and 30 mg mL−1) and incubated aerobically at different temperatures (4, 10, 16, 22 and 30 °C) in order to test its ability to accomplish the bioconversion of LA to conjugated linoleic acid (CLA). Temperatures and LA concentrations producing the highest conversion of LA to CLA in the initial trials were tested further using micro‐anaerobic conditions and a lower initial pH (5.5).

RESULTS: Data showed that production of CLA exhibited variations with regard to the fermentation conditions used. The highest production of CLA (0.108 mg mL−1) was measured in a broth containing 20 mg mL−1 free LA that was incubated aerobically at 10 °C for 30 h. When the initial pH of the reaction medium was reduced from 6.5 to 5.5, CLA production decreased. Micro‐aerobic conditions reduced the ability of Lb. reuteri to produce CLA, since production of CLA under aerobic conditions was at least 1.4 times greater.

CONCLUSION: Production of CLA by Lb. reuteri at low temperatures and relatively high substrate concentrations provides novel opportunities for the development of functional foods with the benefits of enrichment in CLA and probiotic bacteria. Copyright © 2008 Society of Chemical Industry
Plant‐mediated synthesis of silver and gold nanoparticles and their applications
Authors: Kumar Vineet , Yadav Sudesh Kumar
Published: August 2008

Nanobiotechnology deals with the synthesis of nanostructures using living organisms. Among the use of living organisms for nanoparticle synthesis, plants have found application particularly in metal nanoparticle synthesis. Use of plants for synthesis of nanoparticles could be advantageous over other environmentally benign biological processes as this eliminates the elaborate process of maintaining cell cultures. Biosynthetic processes for nanoparticles would be more useful if nanoparticles were produced extracellularly using plants or their extracts and in a controlled manner according to their size, dispersity and shape. Plant use can also be suitably scaled up for large‐scale synthesis of nanoparticles. In view of this, we have reviewed here the use of plants or their extracts in the synthesis of silver and gold nanoparticles for various human applications. Copyright © 2008 Society of Chemical Industry
Ability of sorption–desorption experiments to predict potassium leaching from calcareous soils
Authors: Jalali Mohsen , Kolahchi Zahra
Published: August 2008

When potassium (K+) fertilizers are applied to the soil, K+ is subject to displacement through the soil profile. Leaching can play an important role in agricultural K+ losses that can decrease groundwater quality. To avoid overfertilization, estimation of K+ leaching from soil is important. The ability of the soils to retain K+ against leaching varies according to the adsorption coefficient of the soils. The aim of this study was to relate the K+ leaching from a wide range of calcareous soils to the values obtained from a sorption–desorption experiment. The soil columns were leached with 10 mM CaCl2 solution and the leachate was analyzed for K+. The breakthrough curves for K+ were different, and the amounts of K+ leached varied considerably between different soils. In these calcareous soils where crops are irrigated with water containing significant concentrations of Ca2+ and other cations, large amounts of K+ will be leached. Cumulative K+ leached after five pore volumes leaching with 10 mM CaCl2 was significantly (r = 0.776, p < 0.01) related to the equilibrium K+ concentration. The results of this study enabled us in many cases to estimate the K+ leaching from soil without conducting column experiments, minimizing the laborotary work.
Phosphorus dynamics in peat‐based substrates
Authors: Khandan‐Mirkohi Azizollah , Schenk Manfred K.
Published: August 2008

The mobility of nutrients in soils is well characterized, whereas little information is available for common horticultural substrates based on peat. Aim of the current study was to investigate the mobility and dynamics of phosphorus (P) as well as the parameters involved in P transport to plant roots in peat‐based substrates. A series of experiments was run to determine the impedance factor (f) and the buffer power (b). The impedance factor was determined for black peat and black peat mixed with 20% and 40% (v/v) of mineral component at volumetric water content (θ) of 40%, 50%, 60%, and 70% and at different diffusion time. Buffer power was calculated for black peat and black peat mixed with 20% (v/v) of seven different mineral components. Phosphorus was applied at rates of 0, 35, and 100 mg (L substrate–1), respectively. The impedance factor was not affected by addition of the mineral component to peat. However, f increased from 0.03 to 0.2, by increasing θ from 40% to 60%, indicating that water content has a significant effect on this parameter. Substrate‐solution P ranged from 0.3 to 27 and from 1 to 95 mg P (L solution)–1 for the P‐application rate of 35 and 100 mg P (L substrate)–1, respectively. Buffer power of the substrates ranged from 1 to 17.25 depending on the mineral component, and it was positively correlated with oxalate‐soluble Fe and Al in the substrate. The calculated effective diffusion coefficient for P in the substrate was in the range of 10–7 to 10–8 cm2 s–1. This high value could be attributed mostly to the low buffer power rather than to the high impedance factor.
Molecular imaging and darkfield microspectroscopy of live cells using gold plasmonic nanoparticles
Authors: Wax A. , Sokolov K.
Published: August 2008

Noble metal nanoparticles exhibit a plasmonic resonance that provides them with unique optical properties. The sensitivity of the plasmonic resonance to the surrounding dielectric environment has lead to the development of metal nanoparticles as the basis of biosensing schemes. The sharp enhancement in scattering and absorption at the plasmonic resonance frequency has been exploited to develop metal nanoparticles as imaging contrast agents. In this review article, we recap recent efforts that combine both of these features of metal nanoparticles to enable simultaneous molecular imaging and environmental sensing through the use of darkfield microspectroscopy schemes. Recent experimental results demonstrate molecular imaging of epidermal growth factor receptor in live cancer cells and show that additional information can be obtained by monitoring changes in the plasmonic resonance through darkfield microspectroscopy.
Stochastic immersed boundary method incorporating thermal fluctuations
Authors: Atzberger Paul J. , Kramer Peter R. , Peskin Charles S.
Published: August 2008

We give a brief introduction to the stochastic immersed boundary method which allows for simulation of small length‐scale physical systems in which elastic structures interact with a fluid flow in the presence of thermal fluctuations. The conventional immersed boundary method is extended to account for thermal fluctuations by introducing stochastic forcing terms in the fluid equations. This gives a system of stiff SPDE's for which standard numerical approaches perform poorly. We discuss a numerical method derived using stochastic calculus to overcome the stiff features of the equations. We then discuss results which indicate that the method captures physical features predicted by statistical mechanics for small length‐scale systems. The stochastic immersed boundary method holds promise as a numerical approach in simulating microscopic mechanical systems in which thermal fluctuations play a fundamental role. A more detailed discussion of this work is given in [1, 2, 3]. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spectral computations: from operators to matrices
Authors: d'Almeida F. D. , Vasconcelos P. B.
Published: August 2008

In this work we will address the problem of finding spectral values and bases for the corresponding spectral subspaces for a bounded operator on a Banach space. We will make a bridge between the spectral problem for the continuous operator and the computation of the eigenpairs of a matrix. This approximate problem results first from an approximation by a sequence of continuous operators with finite rank, followed by the reduction to a spectral problem for an operator whose domain as well as range are finite dimensional. Some discussion on defect correction procedures will be also presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Computing minimal optimization horizons for stabilizing unconstrained MPC schemes
Authors: Grüne Lars
Published: August 2008

We present a method for the computation of minimal stabilizing optimization horizons in MPC schemes without stabilizing terminal constraints. The method applies to general nonlinear control systems satisfying a controllability assumption. Key idea is the formulation of a small linear program whose solution determines the minimal horizon. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A best‐fit kinetic model for the walk of myosin V
Authors: Hoyle Rebecca B. , Skau Karl I. , Turner Matthew S.
Published: August 2008

We model the stepping cycle of myosin V, a processive molecular motor, and develop a novel scheme to compare our results with experimental data.[1] (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Towards explicit evaluation of pharmacokinetic outcomes of patient drug intake behaviour
Authors: Li Jun , Nekka Fahima
Published: August 2008

Poor compliance is now well recognized to seriously compromise drug efficacy. Using a probabilistic approach, we established an analytical compliance‐pharmacokinetic formalism for common drug administration routes. This work allows to further characterize different levels of drug concentration variations directly inherited from patient compliance. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transverse isotropic flow in biphasic materials
Authors: Ricken Tim
Published: August 2008

Biological and artificial tissues like muscles, brain material, saturated paper or other functionally graded porous materials often show a transverse isotropic permeability caused by their inner structure. The transverse isotropic permeability influences the motion of the saturating fluid and with this the overall deformation state of the mixture body. Starting with the multi‐phase Theory of Porous Media, a model is presented to describe this deformation affected by the anisotropic inner permeability. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Generalized discrepancies on the sphere
Authors: Seri Raffaello , Choirat Christine
Published: August 2008

Generalized discrepancies are a class of discrepancies introduced in the seminal paper [1] to measure uniformity of points over the unit sphere in ℝ3. However, convergence to 0 of this quantity has been shown only in the case of spherical t –designs. In the following, we completely characterize sequences for which convergence to 0 of D (𝒫N ;A) holds. The interest of this result is that, when evaluating uniformity on the sphere, generalized discrepancies are much simpler to compute than the well‐known spherical cap discrepancy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
NFFT‐based extension of a particle simulation method using multigrid
Authors: Bolten Matthias , Sutmann Godehard
Published: August 2008

In the calculation of electrostatic problems using multigrid methods, computationally the most expensive part is often the charge assignment to a grid. We show how to improve an existing multigrid method by using an NFFT‐based scheme for this task. Numerical tests show that the new method outperforms the direct charge assignment schemes for the case where smooth charge distributions with large support are considered. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental investigations on the mechanical behavior of filled rubber
Authors: Dämgen Michael , Nackenhorst Udo
Published: August 2008

A lot of experimental results on the elastic as well as on the inelastic behavior of elastomer materials are known. However, so far now systematic examination on defined rubber mixtures has been reported. In this presentation the phenomenology of elastomer materials is characterized on the basis of extension and compression tests performed with dumbbell– and S2–specimen. Stiffness, upturn (stiffness at final deformation), hysteresis and remaining deformation have been analyzed for well defined rubber systems and environmental conditions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling of jointed structures using zero thickness interface elements
Authors: Geisler Johannes , Willner Kai
Published: August 2008

An important contribution to global damping of mechanical devices is structural damping due tomicroslip effects with friction in joint interfaces. In order to investigate the mechanical behaviour in these contact interfaces numerically, a contact element in the context of Finite Element Method (FEM) is presented. The suggested element is an isoparametric zero thickness element which is well suited for the present problem because the contact area is known and only small relative displacements occur. Arbitrary linear or nonlinear constitutive contact models for normal and tangential contact behaviour can be implemented. Using a proper parametrisation of the contact area, it is possible to apply the element in contact interfaces lying arbitrarily in space and in interfaces discretized with distorted elements. This method is described before a numerical example is compared with experimental results. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling and simulation of extrusion of aluminum alloys
Authors: Kayser Tobias , Parvizian Farhad , Hortig Christian , Svendsen Bob
Published: August 2008

The purpose of this work is the modeling and simulation of the material behavior of aluminum alloys during extrusion, cooling and metal forming processes. In particular, the alloys of the 6000 series (Al‐Mg‐Si) and 7000 series (Al‐Zn‐Mg) are relevant here. Under the corresponding conditions, their behavior is controlled mainly by dynamic recovery during the extrusion and static recrystallization during cooling. The current material model is based on the role of the energy stored in the material during extrusion as the driving force for microstructural evolution. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reciprocity in material space
Authors: Kienzler Reinhold
Published: August 2008

In Newtonian mechanics, reciprocity relations of Betti and Maxwell are useful tools in the analysis of engineering problems. Similar reciprocity relations have been established recently in Eshelbian Mechanics. In this contribution, a defect‐interaction problem is investigated and various aspects of reciprocity are studied. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dynamics and family of equilibria in a population kinetics model with cosymmetry
Authors: Kovaleva Ekaterina S. , Tsybulin Vyacheslav G. , Frischmuth Kurt
Published: August 2008

We study dynamics in the population kinetics model which is given by the system of nonlinear parabolic equations with cosymmetry property. The cosymmetry implies the emergence of continuous families of steady states with variable spectrum of stability. Different scenarios of evolution of families of equilibria and nonstationary regimes are analyzed numerically by a finite‐difference scheme which respects the cosymmetry property. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Non‐equilibrium gas‐liquid transition model
Authors: Librovich Bronislav V. , Nowakowski Andrzej F. , Chaer Issa , Tassou Savvas
Published: August 2008

A new rigorous mathematical model for evaporation/condensation, including boiling, has been proposed. A problem of phase transition and in particular evaporation/condensation is one of the most acute problems of modern technology with numerous applications in industry, such as: in refrigeration, distillation in chemical industry. It is very common to use equilibrium evaporation model, which assumes that concentrations of species in the gas phase is always at saturated condition. Such kind of approach can lead to significant errors, resulting in negative concentrations in complex computer simulations. In this work two analytical solution of simplified differential‐algebraic system have been obtained. One of them was deduced using assumption that the process is isothermal and gas volume fraction is constant. In the second solution the assumption about gas volume fraction has been removed. The code for numerical solution of differential‐algebraic system, using conservative scheme, has been developed. It was designed to solve both systems of equations with boiling and without. Numerical calculations of ammonia‐water system with various initial conditions, which correspond to evaporation and/or condensation of both components, have been performed. It has been shown that, although system quickly evolves to quasi equilibrium state (the differences between current and equilibrium concentrations are small) it is necessary to use non‐equilibrium evaporation model, to calculate accurately evaporation/condensation rates, and consequently all other dependent variables. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Automated solution of differential equations
Authors: Logg Anders
Published: August 2008

Differential equations are solved routinely by large computer programs, but the solution process is rarely automated. Each equation requires a different program and each such program requires a considerable amount of work to develop and maintain.

The FEniCS project provides a set of tools that automate important aspects of the solution process, ultimately aiming at a complete automation of computational mathematical modeling, including the automation of discretization, discrete solution, error control, modeling and optimization. A key component of FEniCS is the FEniCS Form Compiler (FFC), which automates the discretization of differential equations by taking as input a variational problem in mathematical notation and generating highly efficient optimized low‐level code for the evaluation of the corresponding discrete operator. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)