bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of weak, interrupted sinusoidal low frequency magnetic field on neural regeneration in rats: Functional evaluation
Authors: Bervar Marijan 
Published: May 2005

AbstractA study of the effect of weak, interrupted sinusoidal low frequency magnetic field (ISMF) stimulation on regeneration of the rat sciatic nerve was carried out. In the experiment, 60 Wistar rats were used: 24 rats underwent unilateral sciatic nerve transection injury and immediate surgical nerve repair, 24 rats underwent unilateral sciatic nerve crush injury, and the remaining 12 rats underwent a sham surgery. Half of the animals (n = 12) with either sciatic nerve lesion were randomly chosen and exposed between a pair of Helmholtz coils for 3 weeks post‐injury, 4 h/day, to an interrupted (active period to pause ratio = 1.4 s/0.8 s) sinusoidal 50 Hz magnetic field of 0.5 mT. The other half of the animals (n = 12) and six rats with sham surgery were used for two separate controls. Functional recovery was followed for 6 weeks for the crush injuries and 7½ months for the transection injuries by video assisted footprint analysis in static conditions and quantified using a recently revised static sciatic index (SSI) formula. We ascertained that the magnetic field influence was weak, but certainly detectable in both injury models. The accuracy of ISMF influence detection, determined by the one‐way repeated measures ANOVA test, was better for the crush injury model: F(1, 198) = 9.0144, P = .003, than for the transection injury model: F(1, 198) = 6.4826, P = .012. The Student–Newman–Keuls range test for each response day yielded significant differences (P < .05) between the exposed and control groups early in the beginning of functional recovery and later on from the points adjacent to the beginning of the plateau, or 95% of functional recovery, and the end of observation. These differences probably reflect the ISMF systemic effect on the neuron cell bodies and increased and more efficient reinnervation of the periphery. Bioelectromagnetics 26:351–356, 2005. © 2005 Wiley‐Liss, Inc.
Perception of local DC and AC electric fields in humans
Authors: Chapman C. Elaine , Blondin Jean‐Pierre , Lapierre Anne Marie , Nguyen Duc H. , Forget Robert , Plante Michel , Goulet Daniel 
Published: May 2005

AbstractThe goal of this study was to address some of the factors that contribute to the human ability to detect the presence of weak electric fields generated by direct current (DC) and alternating current (AC) sources. An exposure chamber allowed us to expose a limited surface of the body (forearm and hand) to DC fields of up to 65 kV/m and AC fields up to a maximum of 35 kV/m (frequency 60 Hz). Perception was examined using a staircase procedure and a rating procedure derived from signal detection theory. Sixteen subjects participated in the experiments, and none detected the local DC fields. In contrast, 9/16 subjects were sensitive to local AC electric fields, although detection thresholds (index of sensitivity, d′ = 1.0) were widely variable between subjects. When regional exposure was limited to the dorsal forearm, performance was similar to that seen when the forearm and hand were exposed. In contrast, subjects did not reliably detect the AC electric fields when exposure was limited to the hand (either hairy or glabrous skin), although a minority of subjects (3/9) showed some evidence of detecting fields presented to the glabrous palm. Subjects were unable to detect AC electric fields when the hair was removed from the forearm and hand, suggesting that the evoked sensation is mainly dependent on movement of hair located in the exposed region. Bioelectromagnetics 26:357–366, 2005. © 2005 Wiley‐Liss, Inc.
Controversial cytogenetic observations in mammalian somatic cells exposed to extremely low frequency electromagnetic radiation: A review and future research recommendations
Authors: Vijayalaxmi  , Obe Guenter 
Published: May 2005

AbstractDuring the years 1990–2003, a large number of investigations were conducted using animals, cultured rodent and human cells as well as freshly collected human blood lymphocytes to determine the genotoxic potential of exposure to nonionizing radiation emitted from extremely low frequency electromagnetic fields (EMF). Among the 63 peer reviewed scientific reports, the conclusions from 29 studies (46%) did not indicate increased damage to the genetic material, as assessed from DNA strand breaks, incidence of chromosomal aberrations (CA), micronuclei (MN), and sister chromatid exchanges (SCE), in EMF exposed cells as compared with sham exposed and/or unexposed cells, while those from 14 investigations (22%) have suggested an increase in such damage in EMF exposed cells. The observations from 20 other studies (32%) were inconclusive. This study reviews the investigations published in peer reviewed scientific journals during 1990–2003 and attempts to identify probable reason(s) for the conflicting results. Recommendations are made for future research to address some of the controversial observations. Bioelectromagnetics 26:412–430, 2005. © 2005 Wiley‐Liss, Inc.
Influence of pulsed electromagnetic field with different pulse duty cycles on neurite outgrowth in PC12 rat pheochromocytoma cells
Authors: Zhang Y. , Ding J. , Duan W. , Fan W. 
Published: May 2005

AbstractThe influence of low frequency (50 Hz repetition rate) pulsed electromagnetic field (EMF) on PC12 cell neurite outgrowth in vitro was investigated in this study. We studied the percentage of neurite bearing cells, average length of neurites, and directivity of neurite outgrowth in PC12 cells cultured for 96 h in the presence of nerve growth factor (NGF). PC12 cells were exposed in one incubator to pulsed EMF at 1.36 mT (peak value) generated by a pair of Helmholtz coils, and the control samples were placed in another identical incubator. We found that the pulse duty cycle had significant effect on neurite outgrowth. Low (10%) pulse on‐time significantly inhibited the percentage of neurite bearing cells, but at the same time increased the average length of neurites, while 100% on‐time (DC) had exactly the opposite effects. Furthermore, we found that neurites were prone to extend along the direction of pulsed EMF with 10% pulse on‐time. Our studies show that neurite outgrowth in PC12 cells is sensitive to the pulse duty and this sensitivity was associated with NGF concentration. Bioelectromagnetics 26:406–411, 2005. © 2005 Wiley‐Liss, Inc.
Conformation of gramicidin a in water: Inference from analysis of hydrogen/deuterium exchange behavior by matrix assisted laser desorption ionization mass spectrometry
Authors: Jagannadham M. V. , Nagaraj Ramakrishnan 
Published: May 2005

AbstractGramicidin A (the major component of gramicidin D) is a highly hydrophobic peptide with very little solubility in water. Hence, the conformation of this peptide has been extensively investigated in organic solvents and model membranes, but not in water. The peptide adopts a β6.3‐helical conformation in the monomeric and dimeric forms. We have investigated the conformation of gramicidin A in water by monitoring hydrogen–deuterium exchange by matrix‐assisted laser desorption ionization–time‐of‐flight mass spectrometry. Our results indicate that gramicidin A is monomeric and exists in a highly folded conformation. The metal ion bound forms are clearly discernible in the monomers. The presence of the dimeric form is not observed. It is unlikely this is due to the operating conditions or the method used, as both hetero‐ and homodimers in gramicidin D are detected when methanol is used as a solvent. The present study also establishes that the linear gramicidins retain a history of solvent environment when ions are generated by matrix‐assisted laser desorption ionization and analyzed by time‐of‐flight. © 2005 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 80: 708–713, 2005This 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
Comparison of acetate and propionate uptake by polyphosphate accumulating organisms and glycogen accumulating organisms
Authors: Oehmen Adrian , Yuan Zhiguo , Blackall Linda L. , Keller Jürg 
Published: May 2005

AbstractEnhanced biological phosphorus removal (EBPR) performance is directly affected by the competition between polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs). This study investigates the effects of carbon source on PAO and GAO metabolism. Enriched PAO and GAO cultures were tested with the two most commonly found volatile fatty acids (VFAs) in wastewater systems, acetate and propionate. Four sequencing batch reactors (SBRs) were operated under similar conditions and influent compositions with either acetate or propionate as the sole carbon source. The stimulus for selection of the PAO and GAO phenotypes was provided only through variation of the phosphorus concentration in the feed. The abundance of PAOs and GAOs was quantified using fluorescence in situ hybridisation (FISH). In the acetate fed PAO and GAO reactors, “Candidatus Accumulibacter phosphatis” (a known PAO) and “Candidatus Competibacter phosphatis” (a known GAO) were present in abundance. A novel GAO, likely belonging to the group of Alphaproteobacteria, was found to dominate the propionate fed GAO reactor. The results clearly show that there are some very distinctive differences between PAOs and GAOs in their ability to take up acetate and propionate. PAOs enriched with acetate as the sole carbon source were immediately able to take up propionate, likely at a similar rate as acetate. However, an enrichment of GAOs with acetate as the sole carbon source took up propionate at a much slower rate (only about 5% of the rate of acetate uptake on a COD basis) during a short‐term switch in carbon source. A GAO enrichment with propionate as the sole carbon source took up acetate at a rate that was less than half of the propionate uptake rate on a COD basis. These results, along with literature reports showing that PAOs fed with propionate (also dominated by Accumulibacter) can immediately switch to acetate, suggesting that PAOs are more adaptable to changes in carbon source as compared to GAOs. This study suggests that the PAO and GAO competition could be influenced in favour of PAOs through the provision of propionate in the feed or even by regularly switching the dominant VFA species in the wastewater. Further study is necessary in order to provide greater support for these hypotheses. © 2005 Wiley Periodicals, Inc.
A simple method to estimate the contribution of biological floc and reactor‐solution to mass transfer of oxygen in activated sludge processes
Authors: Mahendraker Venkatram , Mavinic Donald S. , Rabinowitz Barry 
Published: May 2005

AbstractIn this study, the mass transfer coefficient of biological floc (KLabf) was estimated from the mass transfer coefficient of the mixed‐liquor (KLaf) and the reactor‐solution (KLae). The biological floc resistance (BFR) and reactor‐solution resistance (SR) were defined as the reciprocal of KLabf and KLae, respectively, by applying the concept of serial‐resistance originally presented in two‐film theory (Lewis and Whitman (1924) Ind Eng Chem 16:1215–1220). The specific biological floc resistance (SBFR) was defined as biological floc resistance per unit biomass concentration. The data indicated that an activated sludge process yielding low BFR/MLR and BFR/SR tended to produce higher oxygen transfer efficiency. Surprisingly, the reactor‐solution posed the same level of resistance as clean water in all experiments, except in a 5‐day SRT, non‐nitrifying, completely mixed activated sludge (CMAS) process run. Furthermore, SBFR successfully represented biological floc and showed a positive correlation to sludge volume index (SVI). In addition, SBFR/SR and oxygen transfer efficiency (OTEf) followed an exponential relationship for the complete data set. The method of separating the mixed‐liquor into biological floc and reactor‐solution improved the understanding of oxygen transfer under process conditions, without resorting to intrusive techniques or direct handling of fragile biological floc. © 2005 Wiley Periodicals, Inc.
From ‘community’ to ‘neighbourhood’ policing: police community support officers and the ‘police extended family’ in London
Authors: Johnston Les 
Published: May 2005

AbstractCommunity policing lacks a coherent definition. Despite this, the term has been used as a rhetorical device to support nostalgic and state‐centric models of policing. These models are increasingly challenged by diversity. Government has responded to this challenge by advocating an ‘extended family’ model of policing. This paper explores the role of Police Community Support Officers (PCSOs) in the ‘extended family’ model. It draws upon research carried out on PCSOs in London between October 2002 and December 2003. The paper consists of four sections. The first considers the extent of PCSO integration within the Metropolitan Police Service (MPS). The second looks at the impact of PCSO recruitment on the goal of diversifying the MPS workforce. Section three considers public attitudes towards PCSOs in London. The final section considers PCSOs in a national context, focusing on two issues: the relationship between PCSO policy implementation and the ‘evidence‐base’ used to justify it; and the future role of PCSOs in ‘neighbourhood policing’, the latest incarnation of community policing. Copyright © 2005 John Wiley & Sons, Ltd.
Kanamycin A‐Derived Cationic Lipids as Vectors for Gene Transfection
Authors: Sainlos Matthieu , Hauchecorne Michelle , Oudrhiri Noufissa , Zertal‐Zidani Samia , Aissaoui Abderrahim , Vigneron Jean‐Pierre , Lehn Jean‐Marie , Lehn Pierre 
Published: May 2005

AbstractCationic lipids nowadays constitute a promising alternative to recombinant viruses for gene transfer. We have recently explored the transfection potential of a new class of lipids based upon the use of aminoglycosides as cationic polar headgroups. The encouraging results obtained with a first cholesterol derivative of kanamycin A prompted us to investigate this family of vectors further, by modulating the constituent structural units of the cationic lipid. For this study, we have investigated the transfection properties of a series of new derivatives based on a kanamycin A scaffold. The results primarily confirm that aminoglycoside‐based lipids are efficient vectors for gene transfection both in vitro and in vivo (mouse airways). Furthermore, a combination of transfection and physicochemical data revealed that some modifications of the constitutive subunits of kanamycin A‐based vectors were associated with substantial changes in their transfection properties.
Molecular Basis of the Interaction Specificity between the Human Glucocorticoid Receptor and Its Endogenous Steroid Ligand Cortisol
Authors: von Langen Johannes , Fritzemeier Karl‐Heinrich , Diekmann Stephan , Hillisch Alexander 
Published: May 2005

AbstractWe analyzed the binding of five steroids to the human glucocorticoid receptor (hGR) experimentally as well as theoretically. In vitro, we measured the binding affinity of aldosterone, cortisol, estradiol, progesterone, and testosterone to hGR in competition with the ligand dexamethasone. The binding affinity relative to the endogenous ligand cortisol (100 %) is reduced for progesterone (22 %) and aldosterone (20 %) and is very weak for testosterone (1.5 %) and estradiol (0.2 %). In parallel, we constructed a homology model of the hGR ligand‐binding domain (LBD) based on the crystal structure of the human progesterone receptor (hPR). After docking the five steroids into the hGR model ligand‐binding pocket, we performed five separate 4‐ns molecular dynamics (MD) simulations with these complexes in order to study the complex structures. We calculated the binding affinities with two different approaches (MM/PBSA, FlexX) and compared them with the values of the experimentally determined relative binding affinities. Both theoretical methods allowed discrimination between strongly and weakly binding ligands and recognition of cortisol as the endogenous ligand of the hGR in silico. Cortisol binds most strongly due to a nearly perfect steric and electrostatic complementarity with the hGR binding pocket. Chemically similar ligands such as estradiol, testosterone, and progesterone also fit into the hGR binding pocket, but they are unable to form all those contacts with the amino acids of the protein that are necessary to yield a stable, transcriptionally active receptor conformation. Our analysis thus explains the selectivity of the human glucocorticoid receptor for its endogenous ligand cortisol at a molecular level.
Domain‐Selective Ligand‐Binding Modes and Atomic Level Pharmacophore Refinement in Angiotensin I Converting Enzyme (ACE) Inhibitors
Authors: Tzakos Andreas G. , Gerothanassis Ioannis P. 
Published: May 2005

AbstractSomatic ACE (EC 3.4.15.1), a ZnII metalloproteinase, is composed of functionally active N and C domains resulting from tandem gene duplication. Despite the high degree of sequence similarity between the two domains, they differ in substrate and inhibitor specificity and in their activation by chloride ions. Because of the critical role of ACE in cardiovascular and renal diseases, both domains are attractive targets for drug design. Putative structural models have been generated for the interactions of ACE inhibitors (lisinopril, captoril, enalaprilat, keto‐ACE, ramiprilat, quinaprilat, peridoprilat, fosinoprilat, and RXP 407) with both the ACE_C and the ACE_N domains. Inhibitor‐domain selectivity was interpreted in terms of residue alterations observed in the four subsites of the binding grooves of the ACE_C/ACE_N domains (S1: V516/N494, V518/T496, S2: F391/Y369, E403/R381, S1′: D377/Q355, E162/D140, V379/S357, V380/T358, and S2′: D463/E431, T282/S260). The interactions governing the ligand–receptor recognition process in the ACE_C domain are: a salt bridge between D377, E162, and the NH2 group (P1′ position), a hydrogen bond of the inhibitor with Q281, the presence of bulky hydrophobic groups in the P1 and P2′ sites, and a stacking interaction of F391 with a benzyl group in the P2 position. In ACE_N these interactions are: hydrogen bonds of the inhibitor with E431, Y369, and R381, and a salt bridge between the carboxy group in the P2 position of the inhibitor and R500. The calculated complexes were evaluated for their consistency with structure–activity relationships and site‐directed mutagenesis data. A comparison between the calculated interaction free energies and the experimentally observed biological activities was also made. Pharmacophore refinement was achieved at an atomic level, and might provide an improved basis for structure‐based rational design of secondgeneration, domain‐selective inhibitors.
Creating Space for Large Secondary Alcohols by Rational Redesign of Candida antarctica Lipase B
Authors: Magnusson Anders O. , Rotticci‐Mulder Johanna C. , Santagostino Alberto , Hult Karl 
Published: May 2005

AbstractThe active site of Candida antarctica lipase B (CALB) hosts the catalytic triad (Ser‐His‐Asp), an oxyanion hole and a stereospecificity pocket. During catalysis, the fast‐reacting enantiomer of secondary alcohols places its medium‐sized substituent in the stereospecificity pocket and its large substituent towards the active‐site entrance. The largest group to fit comfortably in the stereospecificity pocket is ethyl, and this restricts the number of secondary alcohols that are good substrates for CALB. In order to overcome this limitation, the size of the stereospecificity pocket was redesigned by changing Trp104. The substrate specificity of the Trp104Ala mutant compared to that of the wild‐type lipase increased 270 times towards heptan‐4‐ol and 5500 times towards nonan‐5‐ol; this resulted in the high specificity constants 1100 and 830 s−1 M−1, respectively. The substrate selectivity changed over 400 000 times for nonan‐5‐ol over propan‐2‐ol with both Trp104Ala and the Trp104Gln mutations.
Chemoenzymatic Synthesis of HIV‐1 gp41 Glycopeptides: Effects of Glycosylation on the Anti‐HIV Activity and α‐Helix Bundle‐Forming Ability of Peptide C34
Authors: Wang Lai‐Xi , Song Haijing , Liu Shuwen , Lu Hong , Jiang Shibo , Ni Jiahong , Li Hengguang 
Published: May 2005

AbstractC34 is a 34‐mer peptide derived from the C‐terminal ectodomain of HIV‐1 envelope glycoprotein, gp41. The C34 region in native gp41 carries a conserved N‐glycan at Asn637 and the sequence is directly involved in the virus–host membrane fusion, an essential step for HIV‐1 infection. This paper describes the synthesis of glycoforms of C34 which carry a monosaccharide, a disaccharide, and a native oligosaccharide moiety. The synthesis of the glycopeptide which carries a native high‐mannose type N‐glycan was achieved by a chemoenzymatic approach by using an endoglycosidase‐catalyzed oligosaccharide transfer as the key step. The effects of glycosylation on the inhibitory activity and the helix‐bundle forming ability of C34 were investigated. It was found that glycosylation moderately decreases the anti‐HIV activity of C34 and, in comparison with C34, glyco‐C34 forms less compact six‐helix bundles with the corresponding N‐terminal peptide, N36. This study suggests that conserved glycosylation modulates the anti‐HIV activity and conformations of the gp41 C‐peptide, C34.
Microheterogeneous Solvation for Aminolysis Reactions in AOT‐Based Water‐in‐Oil Microemulsions
Authors: García‐Río Luis , Mejuto Juan Carlos , Pérez‐Lorenzo Moisés 
Published: May 2005

AbstractA kinetic study was carried out on the aminolysis of p‐nitrophenyl acetate (NPA) by n‐decylamine (DEC), piperazine (PIP) and sarcosine (SAR) in AOT/isooctane/water (w/o) microemulsions. By using the pseudophase model both the rate constants at the interface, ${k{{\,{\rm i}\hfill \atop 2\hfill}}}$, and the water microdroplet, ${k{{\,{\rm w}\hfill \atop 2\hfill}}}$, can be obtained. The obtained results show that ${k{{\,{\rm i}\hfill \atop 2\hfill}}}$ increases together with the water content of the microemulsion, whereas ${k{{\,{\rm w}\hfill \atop 2\hfill}}}$ increases as the water content of the system decreases. In the aqueous microdroplet the predominant interaction Na+⋅⋅⋅OH2 causes a decrease in the strength of the hydrogen bonds and therefore facilitates the desolvation of the reagents as W decreases. This desolvation of the reagents causes the increase of ${k{{\,{\rm w}\hfill \atop 2\hfill}}}$ as W decreases. In the interface of the microemulsion the predominant interaction SO3−⋅⋅⋅HOH causes an increase in the electronic density on the water molecules and the consequent decrease in their efficiency in the solvation of the partial negative charge, which develops on the carbonyl oxygen atom in the transition state of the reaction. This decrease in the solvation causes ${k{{\,{\rm i}\hfill \atop 2\hfill}}}$ to decrease together with the water content of the system.
Synthesis and Properties of Chiral Ammonium‐Based Ionic Liquids
Authors: Pernak Juliusz , Feder‐Kubis Joanna 
Published: May 2005

AbstractNew chiral ammonium‐based ionic liquids containing the (1R,2S,5R)‐(−)‐menthyl group can be easily and efficiently prepared under ambient conditions. The preparation and characterization of trialkyl[(1R,2S,5R)‐(−)‐menthoxymethyl]ammonium salts is reported. The salts have been demonstrated to be air‐ and moisture‐stable under ambient conditions and can be readily used in a variety of standard experimental procedures. The single‐crystal X‐ray structure of butyldimethyl[(1R,2S,5R)‐(−)‐menthoxymethyl]ammonium chloride has been determined. The chiral, room‐temperature ionic liquids have been characterized by physical properties such as specific rotation, density, viscosity, thermal degradation, and glass transition temperature. Trialkyl[(1R,2S,5R)‐(−)‐menthoxymethyl]ammonium chloride prototype ionic liquids have also been found to exhibit strong antimicrobial and high antielectrostatic activities.