bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of Noether's Method of Sample Size Determination for the Wilcoxon‐Mann‐Whitney Test
Authors: Vollandt Rüdiger , Horn Manfred 
Published: May 2007

AbstractNOETHER (1987) proposed a method of sample size determination for the Wilcoxon‐Mann‐Whitney test. To obtain a sample size formula, he restricted himself to alternatives that differ only slightly from the null hypothesis, so that the unknown variance o2 of the Mann‐Whitney statistic can be approximated by the known variance under the null hypothesis which depends only on n. This fact is frequently forgotten in statistical practice. In this paper, we compare Noether's large sample solution against an alternative approach based on upper bounds of σ2 which is valid for any alternatives. This comparison shows that Noether's approximation is sufficiently reliable with small and large deviations from the null hypothesis.
Logistic and Nonlogistic Density Functions in Binary Regression with Nonstochastic Covariates
Authors: Tiku M. L. , Vaughan D. C. 
Published: May 2007

AbstractA binary random variable depends on nonstochastic covariates through a density function. The equations that determine the maximum likelihood estimators of the parameters are intractable and difficult to solve iteratively. We develop modified maximum likelihood estimators for both logistic and nonlo‐gistic densities. These estimators are explicit functions of sample observations and are, therefore, easy to compute. They are asymptotically fully efficient and, for small samples, are almost fully efficient. The appropriateness of the logistic density function is also discussed.
On Semi‐Parametric Models in Occult Tumour Experiments
Authors: Rai Shesh N. 
Published: May 2007

AbstractNonparametric statistical analyses of rodent carcinogenicity experiments involving occult tumours of intermediate lethality require numerous interim sacrifices. In recent papers, various semi‐parametric analyses have been proposed which specify a parametric relationship between the death rate in tumour‐bearing and tumour‐free animals as a means of relaxing the requirement for multiple interim sacrifices. These semi‐parametric methods involve different combinations of discrete and continuous time scales for the death and tumour‐onset processes. The effect of combining different scales on this parametric relationship is studied further and illustrated via an example.
Role of Asn2 and Glu7 residues in the oxidative folding and on the conformation of the N‐terminal loop of apamin
Authors: Le‐Nguyen Dung , Chiche Laurent , Hoh François , Martin‐Eauclaire Marie France , Dumas Christian , Nishi Yoshinori , Kobayashi Yuji , Aumelas André 
Published: May 2007

AbstractThe X‐ray structure of [N‐acetyl]‐apamin has been solved at 0.95 Å resolution. It consists of an 1‐7 N‐terminal loop stabilized by an Asn‐β‐turn motif (2–5 residues) and a helical structure spanning the 9–18 residues tightly linked together by two disulfide bonds. However, neither this accurate X‐ray nor the available solution structures allowed us to rationally explain the unusual downfield shifts observed for the Asn2 and Glu7 amide signals upon Glu7 carboxylic group ionization. Thus, apamin and its [N‐acetyl], [Glu7Gln], [Glu7Asp], and [Asn2Abu] analogues and submitted to NMR structural studies as a function of pH. We first demonstrated that the Glu7 carboxylate group is responsible for the large downfield shifts of the Asn2 and Glu7 amide signals. Then, molecular dynamics (MD) simulations suggested unexpected interactions between the carboxylate group and the Asn2 and Glu7 amide protons as well as the N‐terminal α‐amino group, through subtle conformational changes that do not alter the global fold of apamin. In addition, a structural study of the [Asn2Abu] analogue, revealed an essential role of Asn2 in the β‐turn stability and the cis/trans isomerization of the Ala5‐Pro6 amide bond. Interestingly, this proline isomerization was shown to also depend on the ionization state of the Glu7 carboxyl group. However, neither destabilization of the β‐turn nor proline isomerization drastically altered the helical structure that contains the residues essential for binding. Altogether, the Asn2 and Glu7 residues appeared essential for the N‐terminal loop conformation and thus for the selective formation of the native disulfide bonds but not for the activity. © 2007 Wiley Periodicals, Inc. Biopolymers 86: 447–462, 2007.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
Free nitrous acid inhibition on anoxic phosphorus uptake and denitrification by poly‐phosphate accumulating organisms
Authors: Zhou Yan , Pijuan Maite , Yuan Zhiguo 
Published: May 2007

AbstractNitrite has been found in previous research an inhibitor on anoxic phosphorus uptake in enhanced biological phosphorus removal systems (EBPR). However, the inhibiting nitrite concentration reported varied in a large range. This study investigates the nitrite inhibition on anoxic phosphorus uptake by using four different mixed cultures performing EBPR with pH considered an important factor. The results showed that the protonated species of nitrite, HNO2 (or free nitrous acid, FNA), rather than nitrite, is likely the actual inhibitor on the anoxic phosphorus uptake, as revealed by the much stronger correlation of the phosphorus uptake rate with the FNA than with the nitrite concentration. All the four EBPR sludges showed decreased anoxic phosphorus uptake rates with increased FNA concentrations in the studied range of 0.002–0.02 mg HNO2‐N/L. The phosphorus uptake by all four cultures was completely inhibited at 0.02 mg HNO2‐N/L. Granular sludge appeared to be more tolerant to HNO2 than flocular sludge likely due to its stronger resistance to the transfer of nitrite into the bacterial aggregates. Furthermore, denitrification by the phosphorus‐accumulating organisms (PAOs) was also found to be inhibited by HNO2. The denitrification rate decreased by approximately 40% when the FNA concentration was increased from 0.002 to 0.02 mg HNO2‐N/L. Biotechnol. Bioeng. 2007;98: 903–912. © 2007 Wiley Periodicals, Inc.
Model‐based characterization of an amino acid racemase from Pseudomonas putida DSM 3263 for application in medium‐constrained continuous processes
Authors: Bechtold M. , Makart S. , Reiss R. , Alder P. , Panke S. 
Published: May 2007

AbstractThe amino acid racemase with broad substrate specificity from Pseudomonas putida DSM 3263 was overproduced and characterized with respect to application in an integrated multi‐step process (e.g., dynamic kinetic resolution) that—theoretically—would allow for 100% chemical yield and 100% enantiomeric excess. Overexpression of the racemase gene in Escherichia coli delivered cell free extract with easily sufficient activity (20–50 U mg−1 total protein) for application in an enzyme membrane reactor (EMR) setting. Model‐based experimental analysis of a set of enzyme assays clearly indicated that racemization of the model substrates D‐ or L‐methionine could be accurately described by reversible Michaelis–Menten kinetics. The corresponding kinetic parameters were determined from progress curves for the entire suitable set of aqueous‐organic mixtures (up to 60% methanol and 40% acetonitrile) that are eligible for an integrated process scheme. The resulting kinetic expression could be successfully applied to describe enzyme membrane reactor performance under a large variety of settings. Model‐based calculations suggested that a methanol content of 10% and an acetonitrile content of 20% provide maximum productivity in EMR operations. However product concentrations were decreased in comparison to purely aqueous operation due to decreasing solubility of methionine with increasing organic solvent content. Finally, biocatalyst stability was investigated in different solvent compositions following a model‐based approach. Buffer without organic content provided excellent stability at moderate temperatures (20–35°C) while addition of 20% acetonitrile or methanol drastically reduced the half‐life of the racemase. Biotechnol. Bioeng. 2007; 98: 812–824. © 2007 Wiley Periodicals, Inc.
Twenty‐four‐well plate miniature bioreactor high‐throughput system: Assessment for microbial cultivations
Authors: Isett Kevin , George Hugh , Herber Wayne , Amanullah Ashraf 
Published: May 2007

AbstractHigh‐throughput (HT) miniature bioreactor (MBR) systems are becoming increasingly important to rapidly perform clonal selection, strain improvement screening, and culture media and process optimization. This study documents the initial assessment of a 24‐well plate MBR system, Micro (µ)‐24, for Saccharomyces cerevisiae, Escherichia coli, and Pichia pastoris cultivations. MBR batch cultivations for S. cerevisiae demonstrated comparable growth to a 20‐L stirred tank bioreactor fermentation by off‐line metabolite and biomass analyses. High inter‐well reproducibility was observed for process parameters such as on‐line temperature, pH and dissolved oxygen. E. coli and P. pastoris strains were also tested in this MBR system under conditions of rapidly increasing oxygen uptake rates (OUR) and at high cell densities, thus requiring the utilization of gas blending for dissolved oxygen and pH control. The E. coli batch fermentations challenged the dissolved oxygen and pH control loop as demonstrated by process excursions below the control set‐point during the exponential growth phase on dextrose. For P. pastoris fermentations, the µ‐24 was capable of controlling dissolved oxygen, pH, and temperature under batch and fed‐batch conditions with subsequent substrate shot feeds and supported biomass levels of 278 g/L wet cell weight (wcw). The average oxygen mass transfer coefficient per non‐sparged well were measured at 32.6 ± 2.4, 46.5 ± 4.6, 51.6 ± 3.7, and 56.1 ± 1.6 h−1 at the operating conditions of 500, 600, 700, and 800 rpm shaking speed, respectively. The mixing times measured for the agitation settings 500 and 800 rpm were below 5 and 1 s, respectively. Biotechnol. Bioeng. 2007;98: 1017–1028. © 2007 Wiley Periodicals, Inc.
Plea bargaining recommendations by criminal defense attorneys: evidence strength, potential sentence, and defendant preference
Authors: Kramer Greg M. , Wolbransky Melinda , Heilbrun Kirk 
Published: May 2007

AbstractAlthough most criminal cases are disposed of through the process of plea bargaining, little research has focused on this process, and that research has focused on two variables: probability of conviction and potential sentence. This study examined the plea bargaining process from the perspective of the criminal defense attorney and expands prior research by including a third variable: defendant preference regarding plea. Attorney participants (N = 186) responded to a survey containing a vignette presented in a 2 × 2 × 2 between‐subjects design, in which there was systematic manipulation of the following three variables in the context of criminal litigation: likelihood of conviction based on the strength of evidence, defendant preference regarding plea, and potential sentence if convicted. All of these variables were considered important to criminal defense attorneys, and how these variables significantly interacted with each other is explained. We discuss these findings in light of past research and theory that suggested attorneys make plea recommendations according only to probability of conviction and potential sentence, and we discuss implications and directions for future research. Copyright © 2007 John Wiley & Sons, Ltd.
p38MAPK regulation of transcription factor targets in muscle and heart of the hibernating bat, Myotis lucifugus
Authors: Eddy Sean F. , Storey Kenneth B. 
Published: May 2007

AbstractMammalian hibernation combines a profound net metabolic rate suppression with the selective up‐regulation of key genes whose protein products address specific metabolic needs of the hibernator. The signal transduction pathways and transcription factors involved in regulating hibernation‐responsive gene expression are of great interest. The present study suggests an important role for the p38 mitogen‐activated protein kinase (p38MAPK) and selected downstream transcription factors under its control (CREB, ATF‐2, Elk‐1) in the metabolic response by skeletal muscle during hibernation of little brown bats, Myotis lucifugus. Western blotting was used to quantify both total protein and levels of the phosphorylated, active forms of p38MAPK, CREB, ATF‐2 and Elk‐1 in both skeletal muscle and heart of euthermic and hibernating bats. The p38MAPK pathway was not apparently activated in heart during torpor but skeletal muscle showed strong increases (2.2–11‐fold) in the amounts of phosphorylated p38T180/Y182, CREBS133, ATF‐2T69/71 and Elk‐1S383 in the torpid versus aroused state. By contrast both total and phosphorylated levels of Elk‐1 in heart were reduced during hibernation to just 30% of the euthermic values. These data implicate p38MAPK and its transcription factor targets, CREB, ATF‐2 and Elk‐1 in skeletal muscle maintenance during hibernation. Copyright © 2007 John Wiley & Sons, Ltd.
A State‐of‐the‐Art Cyanation of Aryl Bromides: A Novel and Versatile Copper Catalyst System Inspired by Nature
Authors: Schareina Thomas , Zapf Alexander , Mägerlein Wolfgang , Müller Nikolaus , Beller Matthias 
Published: May 2007

AbstractA general protocol for the cyanation of aryl halides with the nontoxic cyanide source K4[Fe(CN)6] using copper catalysis and a ligand system based on 1‐alkylimidazoles is presented. The advantages of this system are the high selectivity, a unique substrate range, easy handling, and inexpensive reagents.
Distribution of type 1 cannabinoid receptor (CB1)‐immunoreactive axons in the mouse hypothalamus
Authors: Wittmann Gábor , Deli Levente , Kalló Imre , Hrabovszky Erik , Watanabe Masahiko , Liposits Zsolt , Fekete Csaba 
Published: May 2007

AbstractType 1 cannabinoid receptor (CB1) is the principal receptor for endocannabinoids in the brain; it mainly occurs in preterminal/terminal axons and mediates retrograde neuronal signaling mechanisms. A large body of physiological and electrophysiological evidence indicates the critical role of CB1 in the regulation of hypothalamic functions. Conversely, the distribution of CB1‐containing axons in the hypothalamus is essentially unknown. Therefore, we have analyzed the distribution and the ultrastructural characteristics of the CB1‐immunoreactive (IR) axons in the mouse hypothalamus by using an antiserum against the C‐terminal 31 amino acids of the mouse CB1. We found that CB1‐IR axons innervated densely the majority of hypothalamic nuclei, except for the suprachiasmatic and lateral mammillary nuclei, in which only scattered CB1‐IR fibers occurred. CB1‐IR innervation of the arcuate, ventromedial, dorsomedial, and paraventricular nuclei and the external zone of the median eminence corroborated the important role of CB1 in the regulation of energy homeostasis and neuroendocrine functions. Ultrastructural studies to characterize the phenotype of CB1‐IR fibers established that most CB1 immunoreactivity appeared in the preterminal and terminal portions of axons. The CB1‐IR boutons formed axospinous, axodendritic, and axosomatic synapses. Analysis of labeled synapses in the paraventricular and arcuate nuclei detected approximately equal numbers of symmetric and asymmetric specializations. In conclusion, the study revealed the dense and differential CB1‐IR innervation of most hypothalamic nuclei and the median eminence of the mouse brain. At the ultrastructural level, CB1‐IR axons established communication with hypothalamic neurons via symmetric and asymmetric synapses indicating the occurrence of retrograde signaling by endocannabinoids in hypothalamic neuronal networks. J. Comp. Neurol. 503:270–279, 2007. © 2007 Wiley‐Liss, Inc.
An in vivo comparison of photoactivatable fluorescent proteins in an avian embryo model
Authors: Stark Danny A. , Kulesa Paul M. 
Published: May 2007

AbstractTracing the lineage or neighbor relationships of cells in a migratory population or deep within an embryo is difficult with current methods. The recent explosion of photoactivatable fluorescent proteins (PAFPs) offers a unique cell labeling tool kit, yet their in vivo performance in intact embryos and applicability have not been thoroughly explored. We report a comparison study of PAGFP, PSCFP2, KikGR, and Kaede analyzed in the avian embryo using confocal and 2‐photon microscopy. PAFPs were introduced into the chick neural tube by electroporation and each photoconverted in the neural crest or cells in the neural tube with exposure to 405 nm light, but showed dramatic differences in photoefficiency and photostability when compared at the same 2% laser power. KikGR and Kaede photoconverted with ratios only slightly lower than in vitro results, but cells rapidly photobleached after reaching maximal photoefficiency. PSCFP2 had the lowest photoefficiency and photoconverted nearly 70 times slower than the other dual‐color PAFPs tested, but was effective at single‐cell marking, especially with 2‐photon excitation at 760 nm. The dual‐color PAFPs were more effective to monitor cell migratory behaviors, since non‐photoconverted neighboring cells were fluorescently marked with a separate color. However, photoconverted cells were limited in all cases to be visually distinguishable for long periods, with PSCFP2 visible from background the longest (48 hr). Thus, photoactivation in embryos has the potential to selectively mark less accessible cells with laser accuracy and may provide an effective means to study cell–cell interactions and short‐term cell lineage in developmental and stem cell biology. Developmental Dynamics 236:1583–1594, 2007. © 2007 Wiley‐Liss, Inc.
Comparison of Cyclodextrin‐Dipeptide Inclusion Complexes in the Absence and Presence of Urea by Means of Capillary Electrophoresis, Nuclear Magnetic Resonance and Molecular Modeling
Authors: Waibel Benjamin , Scheiber Josef , Meier Claudia , Hammitzsch Manuela , Baumann Knut , Scriba Gerhard K. E. , Holzgrabe Ulrike 
Published: May 2007

AbstractThe use of capillary electrophoresis (CE) modified with cyclodextrin (CD) for the separation of stereoisomers of peptides is well established. To increase the solubility of β‐CD, urea is often added to the buffer which may influence the complexation of a CD with a guest molecule. The aim of the present study was to investigate the influence of urea on the complexation between dipeptides and β‐CD using Ala‐Phe and Ala‐Tyr as model compounds. For this purpose three different analytical methods were employed: capillary electrophoresis (CE), 1H‐NMR spectroscopy and molecular dynamics simulations (MD). Electropherograms of the peptide enantiomers were different in the presence and absence of urea. For example, at pH 2.5 in the absence of urea the enantiomers of Ala‐Tyr are not separated in contrast to the use of buffers containing urea. Applying “complexation‐induced chemical shift (CICS)” in NMR spectroscopy and rotating frame Overhauser enhancement spectroscopy (ROESY) revealed differences in the complexation of the peptide enantiomers by β‐CD in the absence and presence of urea suggesting the stabilization of the complex through the phenolic hydroxyl group of tyrosine. MD simulations for different complexes were carried out with consideration of both water and urea molecules in solution. Simulations were performed for 1 ns. In conclusion, NMR spectroscopy and MD methods help to understand the structure of peptide‐CD complexes and the separation and migration behavior in CE. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Polymeric alkenoxy amino acid surfactants: V. Comparison of carboxylate and sulfate head group polymeric surfactants for enantioseparation in MEKC
Authors: Rizvi Syed Asad Ali , Shamsi Shahab A. 
Published: May 2007

AbstractIn this work, six amino acid derived (L‐leucinol, L‐leucine, L‐isoleucinol, L‐isoleucine, L‐valinol, and L‐valine) polymeric chiral surfactants with carboxylate and sulfate head groups that were recently synthesized in our laboratory [30, 33, 35] are compared for the simultaneous enantioseparation of several groups of structurally similar analytes under neutral and basic pH conditions. The physicochemical properties of the monomers and polymers of both classes of sulfated and carboxylated surfactants are compared. In addition, cryogenic high‐resolution electron microscopy showed tubular structures with distinct order of the tubes of 50–100 nm width. A Plackett–Burmann experimental design is used to study the factors that influence the chiral resolution and analysis time of ten structurally related phenylethylamines (PEAs). It is observed that increasing the number of hydroxy groups on the benzene ring of the PEAs resulted in deterioration of enantioseparation using any of the six polymeric surfactants. For all three classes of PEAs, polysodium N‐undecenoxycarbonyl‐L‐amino acidate (poly‐L‐SUCAA)‐type surfactants provided enhanced resolution compared to that of polysodium N‐undecenoxycarbonyl‐L‐amino acid sulfates (poly‐L‐SUCAASS). Several classes of basic and neutral chiral compounds (e.g., β‐blockers benzoin derivatives, PTH‐amino acids, and benzodiazepines) also provided improved chiral separations with poly‐L‐SUCAA. Among the poly‐L‐SUCAAs, polysodium N‐undecenoxycarbonyl‐L‐isoleucine sulfate (poly‐‐SUCL) exhibited overall the best enantioseparation capability for the investigated basic and neutral compounds, while among the poly‐L‐SUCAASs, polysodium N‐undecenoxycarbonyl‐L‐isoleucine sulfate (poly‐L‐SUCILS), and polysodium N‐undecenoxycarbonyl‐L‐valine sulfate (poly‐L‐SUCVS) proved to be equally effective for enantioseparation. This work clearly demonstrates that variation in the head group of polymeric alkenoxy amino acid surfactants has a significant effect on chiral separations.
The concept of gemeinschaft in health planning and management: A Japanese perspective
Authors: Ikegami Naoki 
Published: May 2007

AbstractThe rationale for public involvement in the health sector lies mainly in realizing equity values. As the Gesellschaft relationship of utility maximization cannot be relied upon to arrive at a level of health care regarded as equitable in geographic and other terms, this article argues that there is need to focus on the Gemeinschaft relationship of humanitarian concern. Policy‐makers would, firstly, have to define explicitly the objectives at each policy level; and, secondly, to convince and educate the public and the health providers that such is the way forward. At the operational level, the Japanese‐style management with its emphasis on the mutual commitment of the management and the workers to the organization, would seem to offer a way to unify the fragmented interests within the hospital setting. A comparative study of the health systems of the UK, Japan and the US is made to evaluate the constraints and opportunities each country faces, or would face, in realizing the Gemeinschaft concept at the policy and operational levels. The conclusion reached is that, despite the difficulties, this concept appears to offer a viable alternative to the intensified conflict for resources in the health sector.