bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of a chlorosulfolipid from Ochromonas danica by matrix‐assisted laser desorption/ionization quadrupole ion trap time‐of‐flight mass spectrometry
Authors: Darsow Kai H. , Lange Harald A. , Resch Martin , Walter Christian , Buchholz Rainer 
Published: June 2007

AbstractMatrix‐assisted laser desorption/ionization (MALDI) time‐of‐flight (ToF) mass spectrometry (MS) is an established tool for analyzing high mass molecules, such as proteins, whereas it attracts far less interest in the field of lipid analysis. In the study reported here a new chlorosulfolipid (CSL), 3,8,12,15‐tetrachloroeicosane‐1,17,18‐triyl tris(hydrogen sulfate), was identified from the alga Ochromonas danica and de novo characterized by matrix‐assisted laser desorption/ionization quadrupole ion trap time‐of‐flight (MALDI‐QIT‐ToF) MS in negative ion mode. This method provides an effective alternative for the analysis of compounds directly derived from organic cell extracts. For MALDI analyses several frequently used solid MALDI matrices as well as some ionic liquid matrices (ILMs) were tested to enhance the analyte response to UV‐laser and its ionization. The molecular weight of the observed compound could be determined as Li‐, Na‐ and K‐adducts [M+Me2H]−. The characteristic isotopic patterns of the measured ions and the well‐allocated molecular fragments by MS1, MS2 and MS3 indicate the fourfold chlorination and threefold sulfation of the investigated compound. The MS fragmentation alongside of the chlorine‐bearing C‐atoms is accompanied by the generation of a double bond at the opposite fragment in MS1. This obtained fragmentation pattern provides an insight into the allocation of the chlorine‐bearing C‐atoms along the carbon chain. Copyright © 2007 John Wiley & Sons, Ltd.
Double acylation for identification of amino‐terminal peptides of proteins isolated by polyacrylamide gel electrophoresis
Authors: Sanchez Aniel , Ramos Yassel , Solano Yanni , Gonzalez Luis Javier , Besada Vladimir , Betancourt Lazaro , Gil Jeovanis , Alvarez Felix , Rodriguez Meilyn , Perez Lincidio , Pujol Merardo , Padron Gabriel 
Published: June 2007

AbstractWe report here a method for the identification of free or blocked N‐terminal peptide of in‐gel digested isolated proteins. The primary amino groups of the gel‐entrapped protein are blocked with normal acetic or succinic anhydride, and the protein is digested with a high‐specificity protease. The generated peptides are treated with an equimolar mixture of normal and deuterated acetic anhydride. Upon mass spectrometric analysis internal peptides display a complex isotopic ion distribution while the N‐terminal peptide shows a normal isotopic ion distribution. The procedure was applied to the identification of the N‐terminus of individual and protein mixtures isolated by sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS‐PAGE). Copyright © 2007 John Wiley & Sons, Ltd.
Optimization of an isotope dilution gas chromatography/mass spectrometry method for the detection of endogenous estrogen metabolites in urine samples
Authors: Knust Ulrike , Strowitzki Thomas , Spiegelhalder Bertold , Bartsch Helmut , Owen Robert Wyn 
Published: June 2007

AbstractA gas chromatography/mass spectrometry (GC/MS) method for the simultaneous quantitation of ten estrogen metabolites in human urine was optimized. The method consists of initial enzymatic hydrolysis of the estrogen conjugates using β‐glucuronidase followed by solid‐phase extraction (SPE) on Sep‐pak C18 columns and further sample purification by ion‐exchange chromatography on QAE‐Sephadex cartridges in the acetate form. QAE‐Sephadex cartridges in the borate form were used to separate estrogens into two fractions: one fraction containing estrogens lacking vicinal cis‐hydroxyls (Fr 1) and another containing estrogens possessing vicinal cis‐hydroxyls (catecholestrogens; Fr 2). Finally, following O‐trimethylsilyl ether derivatization, the estrogens were analyzed by GC/MS in the selected ion monitoring mode. Estrogens were quantitated using deuterated internal standards, which were added to the samples at the initiation of the work‐up procedures. After addition to estrogen‐low male human samples the standards showed good chromatographic linear response and reproducibility. A reduction in the number of steps and improvements in the robustness of the work‐up procedures were achieved. The modified method described is less complex, amenable to use with commercially available SPE columns and fulfils all the reliability criteria, resulting in highly specific and accurate results. Copyright © 2007 John Wiley & Sons, Ltd.
Robustness analysis of an adjoint optimal iterative learning controller with experimental verification
Authors: Ratcliffe James D. , Hätönen Jari J. , Lewin Paul L. , Rogers Eric , Owens David H. 
Published: June 2007

AbstractA new modification to the steepest‐descent algorithm for discrete‐time iterative learning control is developed for plant models with multiplicative uncertainty. A theoretical analysis of the algorithm shows that if a tuning parameter is selected to be sufficiently large, the algorithm will result in monotonic convergence provided the plant uncertainty satisfies a positivity condition. This is a major improvement when compared to the standard version of this algorithm, which lacks a mechanism for finding a balance between convergence speed and robustness. The proposed algorithm has been investigated experimentally on an industrial gantry robot and found to display a high degree of robustness to both plant modelling error and initial state error. The algorithm also exhibits both long‐term performance and excellent tracking performance, as demonstrated by experimental tests of up to 4000 iterations. To further examine robustness, the plant has been approximated by simple models including one consisting of an integrator and a gain. A simple tuning rule for this reduced model is proposed, which generates a stable system with a good rate of convergence. The robustness properties of the steepest descent algorithm have then been experimentally verified. Copyright © 2007 John Wiley & Sons, Ltd.
Interval estimation of binomial proportion in clinical trials with a two‐stage design
Authors: Tsai Wei‐Yann , Chi Yunchan , Chen Chia‐Min 
Published: June 2007

AbstractGenerally, a two‐stage design is employed in Phase II clinical trials to avoid giving patients an ineffective drug. If the number of patients with significant improvement, which is a binomial response, is greater than a pre‐specified value at the first stage, then another binomial response at the second stage is also observed. This paper considers interval estimation of the response probability when the second stage is allowed to continue. Two asymptotic interval estimators, Wald and score, as well as two exact interval estimators, Clopper–Pearson and Sterne, are constructed according to the two binomial responses from this two‐stage design, where the binomial response at the first stage follows a truncated binomial distribution. The mean actual coverage probability and expected interval width are employed to evaluate the performance of these interval estimators. According to the comparison results, the score interval is recommended for both Simon's optimal and minimax designs. Copyright © 2007 John Wiley & Sons,
Ltd.
Coverage‐adjusted entropy estimation
Authors: Vu Vincent Q. , Yu Bin , Kass Robert E. 
Published: June 2007

AbstractData on ‘neural coding’ have frequently been analyzed using information‐theoretic measures. These formulations involve the fundamental and generally difficult statistical problem of estimating entropy. We review briefly several methods that have been advanced to estimate entropy and highlight a method, the coverage‐adjusted entropy estimator (CAE), due to Chao and Shen that appeared recently in the environmental statistics literature. This method begins with the elementary Horvitz–Thompson estimator, developed for sampling from a finite population, and adjusts for the potential new species that have not yet been observed in the sample—these become the new patterns or ‘words’ in a spike train that have not yet been observed. The adjustment is due to I. J. Good, and is called the Good–Turing coverage estimate. We provide a new empirical regularization derivation of the coverage‐adjusted probability estimator, which shrinks the maximum likelihood estimate. We prove that the CAE is consistent and first‐order optimal, with rate OP(1/log n), in the class of distributions with finite entropy variance and that, within the class of distributions with finite qth moment of the log‐likelihood, the Good–Turing coverage estimate and the total probability of unobserved words converge at rate OP(1/(log n)q). We then provide a simulation study of the estimator with standard distributions and examples from neuronal data, where observations are dependent. The results show that, with a minor modification, the CAE performs much better than the MLE and is better than the best upper bound estimator, due to Paninski, when the number of possible words m is unknown or infinite. Copyright © 2007 John Wiley & Sons, Ltd.
A Bayesian cost–benefit approach to the determination of sample size in clinical trials
Authors: Kikuchi Takashi , Pezeshk Hamid , Gittins John 
Published: June 2007

AbstractCurrent practice for sample size computations in clinical trials is largely based on frequentist or classical methods. These methods have the drawback of requiring a point estimate of the variance of the treatment effect and are based on arbitrary settings of type I and II errors. They also do not directly address the question of achieving the best balance between the cost of the trial and the possible benefits from using the new treatment, and fail to consider the important fact that the number of users depends on the evidence for improvement compared with the current treatment. Our approach, Behavioural Bayes (or BeBay for short), assumes that the number of patients switching to the new medical treatment depends on the strength of the evidence that is provided by clinical trials, and takes a value between zero and the number of potential patients. The better a new treatment, the more the number of patients who want to switch to it and the more the benefit is obtained. We define the optimal sample size to be the sample size that maximizes the expected net benefit resulting from a clinical trial. Gittins and Pezeshk (Drug Inf. Control 2000; 34:355–363; The Statistician 2000; 49(2):177–187) used a simple form of benefit function and assumed paired comparisons between two medical treatments and that the variance of the treatment effect is known. We generalize this setting, by introducing a logistic benefit function, and by extending the more usual unpaired case, without assuming the variance to be known. Copyright © 2007 John Wiley & Sons, Ltd.
Firm performance, rent appropriation, and the strategic resource divestment capability
Authors: Moliterno Thomas P. , Wiersema Margarethe F. 
Published: June 2007

AbstractDynamic capabilities manifest the organizational capacity to purposefully create or modify the firm's resource base. In this paper, we consider resource divestment an important firm‐level resource management capability that manifests a two‐step organizational change routine. Firms must first be motivated to engage in resource divestment, and then decide which resources should be ‘sold off.’ In exploring this firm‐level capability, we employ factor market theory to consider the ‘seller side’ of the market, and provide a useful framework for conceptualizing how firms generate competitive advantage through resource divestment. We test our model of the resource divestment capability with a dataset of professional baseball franchises during the period 1969–83. Copyright © 2007 John Wiley & Sons, Ltd.
Effects of intravenous glucose on dopaminergic function in the human brain in vivo
Authors: Haltia Lauri T. , Rinne Juha O. , Merisaari Harri , Maguire Ralph P. , Savontaus Eriika , Helin Semi , Någren Kjell , Kaasinen Valtteri 
Published: June 2007

AbstractDopamine is known to regulate food intake by modulating food reward via the mesolimbic circuitry of the brain. The objective of this study was to compare the effects of high energy input (i.v. glucose) on striatal and thalamic dopamine release in overweight and lean individuals. We hypothesized that glucose would induce dopamine release and positive ratings (e.g., satiety) in Behavioral Analog Scales, particularly in food‐deprived lean subjects. [11C]raclopride PET was performed for 12 lean (mean BMI = 22 kg/m2) and 12 overweight (mean BMI = 33 kg/m2) healthy subjects. Each subject was imaged twice in a blinded counter‐balanced setting, after 300 mg/kg i.v. glucose and after i.v. placebo. Dopamine D2 receptor binding potentials (BPs) were estimated. The voxel‐based analysis of the baseline scans indicated lower striatal BPs in the overweight group and a negative correlation between BMIs and BPs. Intravenous glucose did not have a significant effect on BPs in overweight or lean subjects (male and female groups combined). However, BP changes were opposite in the two gender groups. In male subjects, significant BP reductions after glucose were seen in the right and left caudate nucleus, left putamen, and right thalamus. In female subjects, increases in BP secondary to glucose were seen in the right caudate nucleus and right and left putamen. The sexually dimorphic effect of glucose was seen in both overweight and lean subjects. Although gender differences were not among the a priori hypotheses of the present study and, therefore, they must be considered to be preliminary findings, we postulate that this observation is a reflection of an interaction between glucose, sex steroids (estrogen), leptin, and dopamine. Synapse 61:748–756, 2007. © 2007 Wiley‐Liss, Inc.
Ritanserin reverses repeated methamphetamine‐induced behavioral and neurochemical sensitization in mice
Authors: Ago Yukio , Nakamura Shigeo , Kajita Naoko , Uda Misato , Hashimoto Hitoshi , Baba Akemichi , Matsuda Toshio 
Published: June 2007

AbstractChronic administration of methamphetamine (METH) elicits progressive enhancement of locomotor activity known as behavioral sensitization. We have recently shown that chronic METH enhanced METH challenge‐induced increase in 5‐HT levels in the prefrontal cortex and that 5‐HT1A receptor activation attenuated this neurochemical sensitization as well as behavioral sensitization. This study examined whether the nonselective 5‐HT2 receptor antagonist, ritanserin affects METH‐induced behavioral and neurochemical sensitization in mice. Ritanserin at doses of 1 and 3 mg/kg inhibited the development and expression of METH‐induced behavioral sensitization in a dose‐dependent manner. Furthermore, chronic administration of ritanserin for a week attenuated the maintenance of behavioral sensitization, indicating the improvement of established behavioral sensitization. Microdialysis analysis showed that chronic ritanserin inhibited the neurochemical sensitization that chronic METH enhanced METH challenge‐induced increase in extracellular 5‐HT levels in the prefrontal cortex. Furthermore, acute ritanserin inhibited METH challenge‐induced increase in extracellular 5‐HT but not DA levels in the prefrontal cortex. These results suggest that 5‐HT2 receptors are involved in METH‐induced hyperactivity and behavioral sensitization in mice. Synapse 61:757–763, 2007. © 2007 Wiley‐Liss, Inc.
Evaluation of distribution of adenosine A2A receptors in normal human brain measured with [11C]TMSX PET
Authors: Mishina Masahiro , Ishiwata Kiichi , Kimura Yuichi , Naganawa Mika , Oda Keiichi , Kobayashi Shiro , Katayama Yasuo , Ishii Kenji 
Published: June 2007

AbstractAdenosine A2A receptor (A2AR) is thought to interact with dopamine D2 receptor. Selective A2AR antagonists have attracted attention as the treatment of Parkinson's disease. In this study, we investigated the distribution of the A2ARs in the living human brain using positron emission tomography (PET) and [7‐methyl‐11C]‐(E)‐8‐(3,4,5‐trimethoxystyryl)‐1,3,7‐trimethylxanthine ([11C]TMSX). We recruited five normal male subjects. A dynamic series of PET scans was performed for 60 min, and the arterial blood was sampled during the scan to measure radioactivity of the parent compound and labeled metabolites. Circular regions of interest of 10‐mm diameter were placed in the PET images over the cerebellum, brainstem, thalamus, head of caudate nucleus, anterior and posterior putamen, frontal lobe, temporal lobe, parietal lobe, occipital lobe, and posterior cingulate gyrus for each subject. A two‐tissue, three‐compartment model was used to estimate K1, k2, k3, and k4 between metabolite‐corrected plasma and tissue time activity of [11C]TMSX. The binding potential (BP) was the largest in the anterior (1.25) and posterior putamen (1.20), was next largest in the head of caudate nucleus (1.05) and thalamus (1.03), and was small in the cerebral cortex, especially frontal lobe (0.46). [11C]TMSX PET showed the largest BP in the striatum in which A2ARs were enriched as in postmortem and nonhuman studies reported, but that the binding of [11C]TMSX was relatively larger in the thalamus to compare with other mammals. To date, [11C]TMSX is the only promising PET ligand, which is available to clinical use for mapping the A2ARs in the living human brain. Synapse 61:778–784, 2007. © 2007 Wiley‐Liss, Inc.
Dietary restriction modulates α‐synuclein expression in the aging rat cortex and hippocampus
Authors: Mladenovic Aleksandra , Perovic Milka , Tanic Nikola , Petanceska Suzana , Ruzdijic Sabera , Kanazir Selma 
Published: June 2007

AbstractDietary restriction (DR) is one of the promising environmental interventions known to attenuate aging and decrease risk of age‐related neurodegenerative disorders. The aim of this study was to assess the effects of DR on expression of α‐synuclein, a presynaptic protein involved in pathogenesis of Parkinson's and some other neurodegenerative diseases, in the cortex and hippocampus of adult, middle‐aged, late middle‐aged, and aged rats. Using Real Time RT‐PCR, the authors report that aging regulates the expression of α‐synuclein in a tissue‐specific manner and that long‐term DR reverts the late age‐related changes of α‐synuclein expression. Synapse 61:790–794, 2007. © 2007 Wiley‐Liss, Inc.
On‐line measurements of oscillating mitochondrial membrane potential in glucose‐fermenting Saccharomyces cerevisiae
Authors: Andersen Ann Zahle , Poulsen Allan K. , Brasen Jens Christian , Olsen Lars Folke 
Published: June 2007

AbstractWe employed the fluorescent cyanine dye DiOC2(3) to measure membrane potential in semi‐anaerobic yeast cells under conditions where glycolysis was oscillating. Oscillations in glycolysis were studied by means of the naturally abundant nicotinamide adenine dinucleotide (NADH). We found that the mitochondrial membrane potential was oscillating, and that these oscillations displayed the same frequency and duration as the NADH oscillations. It was confirmed that DiOC2(3) localizes itself in the mitochondrial membrane and thus reports qualitative changes solely in mitochondrial membrane potential. Our studies showed that glycolytic oscillations perturb the mitochondrial membrane potential and that the mitochondria do not have any controlling effect on the dynamics of glycolysis under these conditions. Depolarization of the mitochondrial membrane by addition of FCCP quenched mitochondrial membrane potential oscillations and delocalized DiOC2(3), while glycolysis continued to oscillate unaffected. Copyright © 2007 John Wiley & Sons, Ltd.
History and dietary husbandry of pangolins in captivity
Authors: Yang Ci Wen , Chen Suming , Chang Chi‐Yen , Lin Mei Fong , Block Erik , Lorentsen Ronald , Chin Jason S.C. , Dierenfeld Ellen S. 
Published: June 2007

AbstractThe objective of this study was to establish a history of feeding and dietary husbandry of pangolin in captivity. Over the past 150 years, several zoos have attempted to maintain pangolins (Manis spp). Most of these zoos have not succeeded in maintaining these animals for long periods, associated largely with dietary problems. This study reviews the historic records of captive pangolins. The dietary husbandry of pangolins in Taipei Zoo is discussed in detail. Zoo Biol 0:1–8, 2007. © 2007 Wiley‐Liss, Inc.
Impaired Emptying of the Retained Distal Stomach Causes Delayed Gastric Emptying after Pylorus‐preserving Pancreaticoduodenectomy
Authors: Shan Yan‐Shen , Hsieh Yu‐Hsiang , Yao Wei‐Jen , Tsai Mei‐Ling , Lin Pin‐Wen 
Published: June 2007

AbstractObjectiveDelayed gastric emptying (DGE) is the major morbidity after pylorus‐preserving pancreaticoduodenectomy (PPPD). Gastroscintigraphy was used to characterize food distribution in the proximal and distal stomach during emptying.Patients and MethodsBetween October 2000 and June 2003, 20 healthy volunteers and 23 PPPD patients underwent single‐phase gastric emptying scintigraphy 14 days after surgery. Scintigraphic studies of the stomach were divided into proximal and distal regions, and the ratio of proximal to distal radiation counts (P/DR) was plotted. Momentary monitor‐displayed images were compared to evaluate meal distribution during emptying.ResultsThere were 21 eligible patients, 12 without symptoms of DGE (sDGE–) and 9 with symptoms of DGE (sDGE+). In healthy volunteers the mean P/DR value was maintained at a level of ≥ 2.5, and momentary images showed dilated proximal and constricted distal stomach throughout meal emptying. In both the solid and liquid phase tests, the average P/DR value for sDGE– patients was slightly lower than that for healthy volunteers, and momentary images showed early emptying of the solid meal. The mean P/DR value for sDGE+ patients was abnormally low and remained constant throughout the assessment. Momentary images showed significant dilatation of the distal stomach, with constant full size. The odds ratio for the change in P/DR per minute decreased after surgery, especially in sDGE+ patients, indicating a loss of contractility of the distal stomach. At the 6‐month follow‐up, the P/DR values exhibited a normal decreasing trend but were lower for sDGE+ patients than for healthy volunteers.ConclusionsThe P/DR curve provides new insight into normal and pathological gastric function. After surgery, temporary loss of contractility of the distal stomach causes symptoms of DGE.