bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multiple options in the past and the present: The impact on inaction inertia
Authors: van Putten Marijke , Zeelenberg Marcel , van Dijk Eric 
Published: July 2008

AbstractInaction inertia is the effect that people do not act on an attractive opportunity only because they previously missed a more attractive opportunity. We investigated the effect of the presence of alternative options on the occurrence of this effect. We hypothesized and found that the likelihood to act on a current opportunity increases when evaluated in the context of another current option compared to when it is presented separately (Experiments 1 and 2). Likelihood of action decreases when the missed opportunity is presented next to another missed opportunity (Experiment 3). We conclude that when multiple options are currently present, the impact of the missed opportunity as a point of reference decreases, and that when multiple options are missed, the impact of these missed opportunities as a point of reference increases. These results are discussed in light of the literatures about inaction inertia and multiple options. Copyright © 2008 John Wiley & Sons, Ltd.
Sensitive periods for developmental toxicity of orally administered artesunate in the rat
Authors: White Tacey E.K. , Clark Robert L. 
Published: July 2008

AbstractBACKGROUND: Artesunate has been reported to cause embryolethality and malformations when administered orally to rats during organogenesis. The purpose of this study was to determine the most sensitive period(s) for the induction of these effects in order to provide clues about possible mechanisms and to identify a short treatment regimen for further studies.METHODS: Pregnant rats were orally administered artesunate (10, 17 or 30 mg/kg/day) on single or multiple days of gestation. Cesarean sections and fetal evaluations were conducted on Day 21 postcoitum (pc).RESULTS: Embryolethality, cardiovascular malformations and a syndrome of skeletal defects were observed after single doses on days 10 to 14 pc, while no developmental effects were observed before (day 9 pc) or after (days 16 or 17 pc) that period. The most sensitive day for embryo lethality was day 11 pc, where lethality occurred with a very steep dose response (postimplantation loss was ∼15% at 10 mg/kg and 100% at 17 mg/kg/day). The most sensitive day for the induction of malformations was day 10 pc. Malformations tended to occur in partially resorbed litters and included cardiovascular defects and bent and misshapen long bones and scapulae.CONCLUSIONS: The sensitive window for developmental toxicity of artesunate in the rat was identified as days 10 to 14 pc. Single oral doses produced embryolethality and similar cardiovascular and skeletal malformations as previously reported in longer term dosing experiments. These single dose treatment regimens could be useful to further investigate the mechanistic basis for artesunate‐induced developmental toxicity. Birth Defects Research (Part B) 2008. © 2008 Wiley‐Liss, Inc.
Bayesian Analysis of Severe Acute Respiratory Syndrome: The 2003 Hong Kong Epidemic
Authors: Lekone Phenyo E. 
Published: July 2008

AbstractThis paper analyzes data arising from a Severe Acute Respiratory Syndrome (SARS) epidemic in Hong Kong in 2003 involving 1755 cases. A discrete time stochastic model that uses a back‐projection approach is proposed. Markov Chain Monte Carlo (MCMC) methods are developed for estimation of model parameters. The algorithm is further extended to integrate numerically over unobserved variables of the model. Applying the method to SARS data from Hong Kong, a value of 3.88 with a posterior standard deviation of 0.09 was estimated for the basic reproduction number. An estimate of the transmission parameter at the beginning of the epidemic was also obtained as 0.149 with a posterior standard deviation of 0.003. A reduction in the transmission parameter during the course of the epidemic forced the effective reproduction number to cross the threshold value of one, seven days after control interventions were introduced. At the end of the epidemic, the effective reproduction number was as low as 0.001 suggesting that the epidemic was brought under control by the intervention measures introduced. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Design of Long‐Term HIV Dynamic Studies Using Semiparametric Mixed‐Effects Models
Authors: Huang Yangxin , Park Jeong‐Gun , Zhu Yiliang 
Published: July 2008

AbstractStudies of HIV dynamics in AIDS research are very important in understanding the pathogenesis of HIV‐1 infection and also in assessing the effectiveness of antiviral therapies. There are many AIDS clinical trials on HIV dynamics currently in development worldwide, giving rise to many design issues yet to be addressed. For example, most studies are focused on short‐term viral dynamics and the existing models may not be applicable to describe long‐term virologic response. In this paper, we use a simulation‐based approach to study the designs of long‐term viral dynamics under semiparametric nonlinear mixed‐effects models. These models not only can preserve the meaningful interpretation of the short‐term HIV dynamics, but also characterize the long‐term virologic responses to antiretroviral (ARV) treatment. We investigate a number of feasible clinical protocol designs similar to those currently used in AIDS clinical trials. In particular, we evaluate whether earlier samplings can result in more useful information about the viral response trajectory; we also evaluate the effectiveness of two strategies: more frequent samplings per subject with fewer subjects versus fewer samplings per subject with more subjects while keeping the total number of samplings constant. The results of our investigation provide quantitative guidance for designing and selecting ARV therapy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In vivo and in vitro characterization of CCK8 bearing a histidine‐based chelator labeled with 99mTc‐tricarbonyl
Authors: D'Andrea Luca D. , Testa Irma , Panico MariaRosaria , Di Stasi Rossella , Caracò Corradina , Tarallo Laura , Arra Claudio , Barbieri Antonio , Romanelli Alessandra , Aloj Luigi 
Published: July 2008

AbstractThe development of receptor targeting radiolabeled ligands has gained much interest in recent years for diagnostic and therapeutic applications in nuclear medicine. Cholecystokinin (CCK) receptors have been shown to be overexpressed in a subset of neuroendocrine and other tumors. We are evaluating binding and biodistribution properties of a CCK8 peptide derivative labeled with 99mTc(I)‐tricarbonyl. The CCK8 peptide was modified at its N‐terminus by adding to its N‐terminus two lysine–histidine modules (KH), where histidine is coupled to the side chain of the lysine ((KH)2‐CCK8). 99mTc(I)‐tricarbonyl was generated with the IsoLink™ kit. A431 cells stably transfected with a cDNA encoding for the human CCK2 receptor were utilized to determine binding affinity, internalization, and retention of the labeled peptide, in comparison with wild‐type A431 cells. A nude mouse tumor model was obtained by generating A431‐CCK2R and A431‐control tumors in opposite flanks of the animals. High specific activity labeling with 99mTc was achieved. In A431‐CCK2R cells, specific saturable binding was observed as well as evident internalization of the radiolabeled peptide after binding. Biodistribution experiments showed rapid, specific localization of (KH)2‐CCK8 on A431‐CCK2R xenografts compared with control tumors, although absolute uptake values were not markedly higher compared with background activity. Clearance of unbound radioactivity was both urinary and hepatobiliary. In imaging experiments, while targeting to CCK2R positive tumors could be appreciated, there was poor contrast between target and nontarget areas. (KH)2‐CCK8 shows adequate in vitro and in vivo properties for CCK2R targeting although improvement of biodistribution warrant further development. © 2008 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 90: 707–712, 2008.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Inactivation of N‐TIMP‐1 by N‐terminal acetylation when expressed in bacteria
Authors: Van Doren Steven R. , Wei Shuo , Gao Guanghua , DaGue Beverly B. , Palmier Mark O. , Bahudhanapati Harinath , Brew Keith 
Published: July 2008

AbstractThe high‐affinity binding of tissue inhibitors of metalloproteinases (TIMPs) to matrix metalloproteinases (MMPs) is essential for regulation of the turnover of the extracellular matrix during development, wound healing, and progression of inflammatory diseases, such as cancer, atherosclerosis, and arthritis. Bacterially expressed N‐terminal inhibitory domains of TIMPs (N‐TIMPs) have been used extensively for biochemical and biophysical study of interactions with MMPs. Titration of N‐TIMP‐1 expressed in E. coli indicates, however, that only about 42% of the protein is active as an MMP inhibitor. The separation of inactive from fully active N‐TIMP‐1 has been achieved both by MMP affinity and by high‐resolution cation exchange chromatography at an appropriate pH, based on a slight difference of charge. Purification by cation exchange chromatography with a Mono S column enriches the active portion of N‐TIMP‐1 to >95%, with Ki of 1.5 nM for MMP‐12. Mass spectra reveal that the inactive form differs from active N‐TIMP‐1 in being N‐terminally acetylated, underscoring the importance of the free α‐NH2 of Cys1 for MMP inhibition. Nα‐acetylation of the CTCVPP sequence broadens the N‐terminal sequence motifs reported to be susceptible to α‐amino acetylation by E. coli N‐acetyl transferases. © 2008 Wiley Periodicals, Inc. Biopolymers 89: 960–968, 2008.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Nucleic acids absorbance in Mid IR and its effect on diagnostic variates during cell division: A case study with lymphoblastic cells
Authors: Sahu Ranjit K. , Mordechai Shaul , Manor Ester 
Published: July 2008

AbstractThe differences in the absorbance in the mid infrared region (Mid IR) between normal and abnormal tissues have been shown to be a possible criterion for the detection of different forms of cancer. The present work aimed to study the effects of cell growth and DNA synthesis on the RNA/DNA ratio, which is a promising parameter for cancer diagnosis by inducing synthesis of DNA. Lymphoblastic cell lines were synchronized by methotrexate and harvested for Fourier transform infrared microscopy (FTIR‐MSP) at 30‐min interval after thymidine addition. The distribution of DNA in the cells/nuclei and variation of nuclear size was studied using the fluorescent dye propidium iodide (PI) and the nuclear volume was calculated from microscopy. We analyzed the ratio of RNA and DNA to quantify the relative amounts during the process by taking the ratios I(1121)/I(1020) (symmetric) and the I(1244)/I(1230) (antisymmetric) phosphate vibrations. The pattern of changes in the ratios overtime obtained in the symmetric and antisymmetric vibrations were similar though the magnitudes were different. Only a minor effect on the RNA/DNA ratio (due to nuclear volume changes) was observed. The effect due to the unfolding of DNA is greatly masked due to RNA absorbance. The effectiveness of this ratio may lie in the increased transcriptional levels in carcinogenic tissues rather than changes occurring due to unfolding and folding of DNA. © 2008 Wiley Periodicals, Inc. Biopolymers 89: 993–1001, 2008.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
The role of weakly polar and H‐bonding interactions in the stabilization of the conformers of FGG, WGG, and YGG; An aqueous phase computational study
Authors: Csontos József , Murphy Richard F. , Lovas Sándor 
Published: July 2008

AbstractThe energetics of intramolecular interactions on the conformational potential energy surface of the terminally protected N‐Ac‐Phe‐Gly‐Gly‐NHMe (FGG), N‐Ac‐Trp‐Gly‐Gly‐NHMe (WGG), and N‐Ac‐Tyr‐Gly‐Gly‐NHMe (YGG) tripeptides was investigated. To identify the representative conformations, simulated annealing molecular dynamics (MD) and density functional theory (DFT) methods were used. The interaction energies were calculated at the BHandHLYP/aug‐cc‐pVTZ level of theory. In the global minima, 10%, 31%, and 10% of the stabilization energy come from weakly polar interactions, respectively, in FGG, WGG, and YGG. In the prominent cases 46%, 62%, and 46% of the stabilization energy is from the weakly polar interactions, respectively, in FGG, WGG, and YGG. On average, weakly polar interactions account for 15%, 34%, and 9% of the stabilization energies of the FGG, WGG, and YGG conformers, respectively. Thus, weakly polar interactions can make an important energetic contribution to protein structure and function. © 2008 Wiley Periodicals, Inc. Biopolymers 89: 1002–1011, 2008.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Investigations of thermotropic phase behavior of newly developed synthetic PEGylated lipids using Raman spectro‐microscopy
Authors: Bista Rajan K. , Bruch Reinhard F. , Covington Aaron M. , Sorger Alexander , Gerstmann Thoralf , Otto Alexander 
Published: July 2008

AbstractIn this article, a temperature‐controlled Raman spectro‐microscopic technique has been utilized to detect and analyze the phase behaviors of two newly developed synthetic PEGylated lipids trademarked as QuSomes™, which spontaneously form liposomes upon hydration in contrast to conventional lipids. The amphiphiles considered in this study differ in their hydrophobic hydrocarbon chain length and contain different units of polyethylene glycol (PEG) hydrophilic headgroups. Raman spectra of these new artificial lipids have been recorded in the spectral range of 500–3100 cm−1 by using a Raman microscope system in conjunction with a temperature‐controlled sample holder. The gel to liquid phase transitions of the sample lipids composed of pure 1,2‐dimyristoyl‐rac‐glycerol‐3‐dodecaethylene glycol (GDM‐12) and 1,2‐distearoyl‐rac‐glycerol‐3‐triicosaethylene glycol (GDS‐23) have been revealed by plotting peak intensity ratios in the CH stretching region as a function of temperature. From this study, we have found that the main phase transitions occur at a temperature of ∼5.2 and 21.2°C for pure GDM‐12 and GDS‐23, respectively. Furthermore, the lipid GDS‐23 also shows a postphase transition temperature at 33.6°C. To verify our results, differential scanning calorimetry (DSC) experiments have been conducted and the results are found to be in an excellent agreement with Raman scattering data. This important information may find application in various studies including the development of lipid‐based novel substances and drug delivery systems. © 2008 Wiley Periodicals, Inc. Biopolymers 89: 1012–1020, 2008.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Computational analysis of glycoside hydrolase family 1 specificities
Authors: Hill Anthony D. , Reilly Peter J. 
Published: July 2008

AbstractGlycoside hydrolase family 1 consists of β‐glucosidases, β‐galactosidases, 6‐phospho‐β‐galactosidases, myrosinases, and other enzymes having similar primary and tertiary structures but diverse specificities. Among these enzymes, β‐glucosidases hydrolyze cellobiose to glucose, and therefore they are key players in any cellulose to glucose process. All family members attack β‐glycosidic bonds between a pyranosyl glycon and an aglycon, but most have little specificity for the aglycon or for the bond configuration. Furthermore, glycon specificity is not absolute. Sixteen family members (six β‐glucosidases, two cyanogenic β‐glucosidases, one 6‐phospho‐β‐galactosidase, two myrosinases, and five β‐glycosidases) have known tertiary structures. We have used automated docking to computationally bind disaccharides with allopyranosyl, galactopyranosyl, glucopyranosyl, mannopyranosyl, 6‐phosphogalactopyranosyl, and 6‐phosphoglucopyranosyl glycons, all linked by β‐(1,2), β‐(1,3), β‐(1,4), and β‐(1,6)‐glycosidic bonds to β‐glucopyranoside aglycons, along with β‐(1,1‐thio)‐allopyranosyl, ‐galactopyranosyl, ‐glucopyranosyl, and ‐mannopyranosyl) β‐glucopyranosides, into all of these structures to investigate the structural determinants of their enzyme specificities. The following are the eight active‐site residues: Glu191, Thr194, Phe205, Asn285, Arg336, Asn376, Trp378, and Trp465 (Zea mays β‐glucosidase numbering), that control a significant amount of glycon specificity. © 2008 Wiley Periodicals, Inc. Biopolymers 89: 1021–1031, 2008.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Microbial bio‐production of a recombinant stimuli‐responsive biosurfactant
Authors: Kaar W. , Hartmann B.M. , Fan Y. , Zeng B. , Lua L.H.L. , Dexter A.F. , Falconer R.J. , Middelberg A.P.J. 
Published: July 2008

AbstractBiosurfactants have been the subject of recent interest as sustainable alternatives to petroleum‐derived compounds in areas ranging from soil remediation to personal and health care. The production of naturally occurring biosurfactants depends on the presence of complex feed sources during microbial growth and requires multicomponent enzymes for synthesis within the cells. Conversely, designed peptide surfactants can be produced recombinantly in microbial systems, enabling the generation of improved variants by simple genetic manipulation. However, inefficient downstream processing is still an obstacle for the biological production of small peptides. We present the production of the peptide biosurfactant GAM1 in recombinant E. coli. Expression was performed in fusion to maltose binding protein using chemically defined minimal medium, followed by a single‐step affinity capture and enzymatic cleavage using tobacco etch virus protease. Different approaches to the isolation of peptide after cleavage were investigated, with special emphasis on rapid and simple procedures. Solvent‐, acid‐, and heat‐mediated precipitation of impurities were successfully applied as alternatives to post‐cleavage chromatographic peptide purification, and gave peptide purities exceeding 90%. Acid precipitation was the method of choice, due to its simplicity and the high purification factor and recovery rate achieved here. The functionality of the bio‐produced peptide was tested to ensure that the resulting peptide biosurfactant was both surface active and able to be triggered to switch between foam‐stabilizing and foam‐destabilizing states. Biotechnol. Bioeng. 2009;102: 176–187. © 2008 Wiley Periodicals, Inc.
Directing vanillin production from ferulic acid by increased acetyl‐CoA consumption in recombinant Escherichia coli
Authors: Lee Eun‐Gyeong , Yoon Sang‐Hwal , Das Amitabha , Lee Sook‐Hee , Li Cui , Kim Jae‐Yean , Choi Myung‐Suk , Oh Deok‐Kun , Kim Seon‐Won 
Published: July 2008

AbstractThe amplification of gltA gene encoding citrate synthase of TCA cycle was required for the efficient conversion of acetyl‐CoA, generated during vanillin production from ferulic acid, to CoA, which is essential for vanillin production. Vanillin of 1.98 g/L was produced from the E. coli DH5α (pTAHEF‐gltA) with gltA amplification in 48 h of culture at 3.0 g/L of ferulic acid, which was about twofold higher than the vanillin production of 0.91 g/L obtained by the E. coli DH5α (pTAHEF) without gltA amplification. The icdA gene encoding isocitrate dehydrogenase of TCA cycle was deleted to make the vanillin producing E. coli utilize glyoxylate bypass which enables more efficient conversion of acetyl‐CoA to CoA in comparison with TCA cycle. The production of vanillin by the icdA null mutant of E. coli BW25113 harboring pTAHEF was enhanced by 2.6 times. The gltA amplification of the glyoxylate bypass in the icdA null mutant remarkably increased the production rate of vanillin with a little increase in the amount of vanillin production. The real synergistic effect of gltA amplification and icdA deletion was observed with use of XAD‐2 resin reducing the toxicity of vanillin produced during culture. Vanillin of 5.14 g/L was produced in 24 h of the culture with molar conversion yield of 86.6%, which is the highest so far in vanillin production from ferulic acid using recombinant E. coli. Biotechnol. Bioeng. 2009;102: 200–208. © 2008 Wiley Periodicals, Inc.
Detailed understanding of enhanced specific antibody productivity in NS0 myeloma cells
Authors: Khoo Soo Hean Gary , Al‐Rubeai Mohamed 
Published: July 2008

AbstractThe understanding of how cellular productivity is modulated in cell lines is of significant importance in the biopharmaceutical industry. Often, single molecular mechanisms fail to fully explain how specific antibody productivity is enhanced during proliferation arrest. Previously, we reported that certain physiological changes occur when proliferation is arrested by p21CIP1 over expression. In this work, we correlate physiological and molecular factors to enhance antibody productivity. Using biomass, cell volume and total cellular protein content as a basis for determining specific productivity, it was found that total cellular protein correlated best with cellular productivity. This meant that there was no preferential increase in antibody production relative to cellular proteins in arrested cultures. However, molecular analysis of mRNA transcription and stability indicated that both processes were altered in arrested cultures resulting in up to threefold increased heavy chain mRNA levels. While flow cytometric analysis revealed that arrested cells had elevated translational capacity for both heavy and light chains, the heavy to light chain polypeptide ratio was 10–50% higher than in the control. This resulted in a lower extracellular accumulation of light chains and a better utilization of cellular resources for the formation of complete antibodies. Active transcriptional regulation of heavy and light chain mRNA and the modulation of translational activities play a vital role in the modulation of overall antibody productivity of these cells. The combined effect of heavy chain mRNA enhancement and the increased cellular assembly capacity was determined to effectively increase specific productivity. Biotechnol. Bioeng. 2009;102: 188–199. © 2008 Wiley Periodicals, Inc.