bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prostatic basal cells in the peripheral and transitional zones: Zonal variation in morphology and in immunophenotype
Authors: Garcia Fernando U. , Haber Marian M. , Chen Xiaoli 
Published: September 2007

AbstractBACKGROUNDBenign prostatic hyperplasia and prostatic adenocarcinoma exhibit prominent zonal predilections. Basal cells from the transitional zone and from the peripheral zone are postulated to have different underlying biological properties. We studied basal cells in both prostatic zones.METHODSTissue microarrays (TMA) were prepared from 65 whole‐mounted prostatectomy specimens with prostatic adenocarcinoma. The transitional zone and peripheral zone were sampled from each prostate. TMA sections were stained with a basal cell cocktail (CK 34βE12 + p63). The immunostaining pattern and the morphology of basal cells were recorded.RESULTSTriangular‐shaped basal cells were highlighted by CK 34βE12 cytoplasmic and p63 nuclear staining. These basal cells had their long axis oriented perpendicular to the basement membrane and their apex toward the lumen interdigited between secretory luminal cells. This morphology was seen in the majority of peripheral zone benign prostatic glands (92.0%) but only a minority of transitional zone benign prostatic glands (18.0%). Basal cells of the transitional zone showed weak or absent CK 34βE12 staining in 65.9% of glands while maintaining p63. All glands with high‐grade prostatic intraepithelial neoplasia (HGPIN) contained the triangular basal cells. In addition, basal cell clusters were identified in 8.7% of peripheral zone glands and 5.2% of HGPIN glands.CONCLUSIONSOur results indicate that the basal cell morphology and the basal cell immunophenotype have a zonal variation. The finding of a unique morphology of basal cells and the presence of basal cell clusters in the peripheral zone suggests that the peripheral zone might be the stem/progenitor cell‐rich area in the human prostates. Prostate 67: 1686–1692, 2007. © 2007 Wiley‐Liss, Inc.
Structure of 2‐deoxy‐scyllo‐inosose synthase, a key enzyme in the biosynthesis of 2‐deoxystreptamine‐containing aminoglycoside antibiotics, in complex with a mechanism‐based inhibitor and NAD+
Authors: Nango Eriko , Kumasaka Takashi , Hirayama Toshifumi , Tanaka Nobuo , Eguchi Tadashi 
Published: September 2007

AbstractA key enzyme in the biosynthesis of clinically important aminoglycoside antibiotics is 2‐deoxy‐scyllo‐inosose synthase (DOIS), which catalyzes carbocycle formation from D‐glucose‐6‐phosphate to 2‐deoxy‐scyllo‐inosose through a multistep reaction. This reaction mechanism is similar to the catalysis by dehydroquinate synthase (DHQS) of the cyclization of 3‐deoxy‐D‐arabino‐heputulosonate‐7‐phosphate to dehydroquinate in the shikimate pathway, but significant dissimilarity between these enzymes is also known, particularly in the stereochemistry of the phosphate elimination reaction and the cyclization. Here, the crystal structures of DOIS from Bacillus circulans and its complex with the substrate analog inhibitor carbaglucose‐6‐phosphate, NAD+, and Co2+ have been determined to provide structural insights into the reaction mechanism. The complex structure shows that an active site exists between the N‐terminal and C‐terminal domains and that the inhibitor coordinates a cobalt ion in this site. Two subunits exist as a dimer in the asymmetric unit. The two active sites of the dimer were observed to be different. One contains a dephosphorylated compound derived from the inhibitor and the other includes the inhibitor without change. The present study suggested that phosphate elimination proceeds through syn‐elimination assisted by Glu 243 and the aldol condensation proceeds via a boat conformation. Also discussed are significant similarities and dissimilarities between DOIS and DHQS, particularly in terms of the structure at the active site and the reaction mechanism. Proteins 2008. © 2007 Wiley‐Liss, Inc.
A chirality index for investigating protein secondary structures and their time evolution
Authors: Pietropaolo Adriana , Muccioli Luca , Berardi Roberto , Zannoni Claudio 
Published: September 2007

AbstractWe propose a methodology for the description of the secondary structure of proteins, based on assigning a chirality parameter to short aminoacid sequences according to their arrangement in space at a certain time. We validated the method on ideal and crystalline structures, showing that it can assign secondary structures and that this assignment is robust with respect to random conformational perturbations. From the values of the index and its pattern along a sequence it is possible to recognize many structural motifs of a protein, and in particular poly‐L‐proline II left‐handed helices, often not detected by secondary structure assignment algorithms.Assigning an instantaneous chirality index to the fragments also allows the dynamics to be studied. With this purpose, molecular dynamics simulations were carried out in water for selected hemoglobin (110 ns) and immunoglobulin antigen fragments (50 ns), showing the capability of the chiral index in identifying the stable secondary structure elements, as well as in following their time evolution and conformational changes during the trajectory. Proteins 2008. © 2007 Wiley‐Liss, Inc.
Impact of alpha‐cypermethrin on honey bees foraging on spring oilseed rape (Brassica napus) flowers in field conditions
Authors: Karise Reet , Viik Eneli , Mänd Marika 
Published: September 2007

AbstractBACKGROUND: Cruciferous oil‐bearing crops have gained in importance worldwide. The expansion of the growing area of these crops has caused a proliferation of pests. Exposure to organophosphate, carbamate and pyrethroid insecticides has been associated with bee poisoning in food crops. This study examines the repellent effect of alpha‐cypermethrin on the number of foraging honey bees, Apis mellifera L., on fields of spring oilseed rape, Brassica napus L. var. oleifera.RESULTS: The first experiment was conducted on differently sprayed 10 m2 experimental plots where alpha‐cypermethrin was applied at different times. Another experiment was conducted on a 4 ha seed production field divided into two parts: one part was treated with alpha‐cypermethrin and the other was not treated with this insecticide. The results show that there was no difference in the number of honey bees between alpha‐cypermethrin‐treated and untreated patches. The result persisted through three observation years, regardless of varying flower and honey bee densities.CONCLUSION: No repellent effect of the insecticide on honey bees was found even 24 h after spraying. The density of oilseed rape flowers most likely played a major role in choosing the foraging area. Copyright © 2007 Society of Chemical Industry
Pesticide residues in beeswax samples collected from honey bee colonies (Apis mellifera L.) in France
Authors: Chauzat Marie‐Pierre , Faucon Jean‐Paul 
Published: September 2007

AbstractIn 2002 a field survey was initiated in French apiaries in order to monitor the health of honey bee colonies (Apis mellifera L.). Studied apiaries were evenly distributed across five sites located in continental France. Beeswax samples were collected once a year over 2 years from a total of 125 honey bee colonies. Multiresidue analyses were performed on these samples in order to identify residues of 16 insecticides and acaricides and two fungicides. Residues of 14 of the searched‐for compounds were found in samples. Tau‐fluvalinate, coumaphos and endosulfan residues were the most frequently occurring residues (61.9, 52.2 and 23.4% of samples respectively). Coumaphos was found in the highest average quantities (792.6 µg kg−1). Residues of cypermethrin, lindane and deltamethrin were found in 21.9, 4.3 and 2.4% of samples respectively. Statistical tests showed no difference between years of sampling, with the exception of the frequency of pyrethroid residues. Beeswax contamination was the result of both in‐hive acaricide treatments and, to a much lesser extent, environmental pollution. Copyright © 2007 Society of Chemical Industry
The incidence of honey bee pests and diseases in England and Wales
Authors: Wilkins Selwyn , Brown Mike A , Cuthbertson Andrew GS 
Published: September 2007

AbstractThe Central Science Laboratory (CSL) National Bee Unit (NBU) has been responsible for maintaining the Integrated Bee Health Programme in England and Wales since the early 1990s. The role of the Bee Health Programme is to protect the honey bee, a major pollinator of agricultural and horticultural crops and wild flora, and to provide up‐to‐date technical support to beekeepers. The Bee Health Programme is funded in England by the Department for Environment, Food and Rural Affairs (Defra) and in Wales by the Welsh Assembly Government (WAG). The work includes inspection of honey bee colonies, disease and pest diagnosis, development of contingency plans for emerging threats, minimising the risk of introduction of potentially serious exotic pests and diseases through importation by import risk analysis and related extension work and consultancy services to both government and industry. There is also an underpinning programme of research and development. © Crown copyright 2007. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.
Risk assessment to honey bees: a scheme developed in France for non‐sprayed systemic compounds
Authors: Alix Anne , Vergnet Christine 
Published: September 2007

AbstractBACKGROUND: Directive 91/414/EEC envisages that the systemic properties of active substances, if any, are taken into account in evaluating the risk posed to the environment by plant protection products. Among others, honey bees may be exposed to substances via this route, which may pose problems when substances with high toxicity are ingested through pollen or nectar. The guidance documents in support of the risk assessment to bees within the framework of Directive 91/414/EEC do not provide detailed technical guidance on how to proceed in a risk assessment for substances with systemic properties.RESULTS: A stepwise approach aiming specifically to assess the risk posed by non‐sprayed systemic substances to bees is therefore proposed. This approach first identifies substances with systemic properties, which should be quantified in plant material as pollen and nectar. Exposure estimates calculated for different categories of bees (e.g. foraging bees), based on expected concentrations of the product in pollen or nectar, may be compared with several toxicity endpoints for acute or chronic effects on adults and/or larvae with a toxicity/exposure ratio, which is a measurement of potential risks.CONCLUSION: Such a ratio is proposed to be used as a trigger for any further refined assessment that would focus on the measurement of effects at the colony level. Copyright © 2007 Society of Chemical Industry
Comparative study of unscreened and screened molecular static linear polarizability in the Hartree–Fock, hybrid‐density functional, and density functional models
Authors: Zope Rajendra R. , Baruah Tunna , Pederson Mark R. , Dunlap B. I. 
Published: September 2007

AbstractThe sum‐over‐states (SOS) polarizabilities are calculated within approximate mean‐field electron theories such as the Hartree–Fock approximation and density functional models using the eigenvalues and orbitals obtained from the self‐consistent solution of the single‐particle equations. The SOS polarizabilities are then compared with those calculated using the finite‐field (FF) method. Three widely used mean‐field models are as follows: (1) the Hartree–Fock (HF) method, (2) the three parameter hybrid generalized gradient approximation (GGA) (B3LYP), and (3) the parameter‐free generalized gradient approximation due to Perdew–Burke–Ernzerhof (PBE). The comparison is carried out for polarizabilities of 142 molecules calculated using the 6‐311++G(d,p) basis set at the geometries optimized at the B3LYP/6‐311G** level. The results show that the SOS method almost always overestimates the FF polarizabilities in the PBE and B3LYP models. This trend is reversed in the HF method. A few exceptions to these trends are found. The mean absolute errors (MAE) in the screened (FF) and unscreened (SOS) polarizability are 0.78, 1.87, and 3.44 Å3 for the HF, B3LYP, and PBE‐GGA methods, respectively. Finally, a simple scheme is devised to obtain FF quality polarizability from the SOS polarizability. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Compound‐specific 81Br/79Br analysis by capillary gas chromatography/multicollector inductively coupled plasma mass spectrometry
Authors: Sylva Sean P. , Ball Lary , Nelson Robert K. , Reddy Christopher M. 
Published: September 2007

AbstractBrominated organic compounds (BOCs) are of great interest in atmospheric chemistry, natural products, geochemistry, and marine chemistry. The Br isotope ratios (81Br and 79Br; average 81Br/79Br = 0.97277) have significant potential for the study of the source, transport, and fate of these compounds. Currently, there is no published method for determining the Br isotopic content of BOCs in complex mixtures. To measure the ratios of stable Br in BOCs on a compound‐specific basis, we assembled a gas chromatography/multicollector inductively coupled plasma mass spectrometry (GC/MCICPMS) system. Background signals, the formation of Ar dimers from organic hydrogen, and the solvent peak did not affect the results. The analysis of three brominated benzenes revealed that 0.3‰ precision can be attained when 0.3 nmol of Br are injected. For samples larger than 0.3 nmol Br, the isotopic precision was within a factor of 3 of the shot‐noise limit, which is the best possible statistical precision attainable avoiding all other sources of noise. Copyright © 2007 John Wiley & Sons, Ltd.
Analysis of low molecular weight acids by negative mode matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Shroff Rohit , Muck Alexander , Svatoš Aleš 
Published: September 2007

AbstractFree 9‐aminoacridine base is demonstrated to be a suitable matrix for negative mode matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometric (MALDI‐TOFMS) analysis of a wide range of low molecular weight organic acids including aliphatic (from acetic to palmitic acid), aromatic acids, phytohormones (e.g. jasmonic and salicylic acids), and amino acids. Low limits of quantitation in the femtomolar range (jasmonic – 250 fmol; caffeic – 160 fmol and salicylic – 12.5 fmol) and linear detector response over two concentration orders in the pico‐ and femtomolar range are extremely encouraging for the direct study of such acids in complex biological matrices. Copyright © 2007 John Wiley & Sons, Ltd.
Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry for the detection of hemoglobins as the protein biomarkers for fecal occult blood
Authors: Lin Shu‐Yao , Shih Shu‐Hung , Wu Deng‐Chyang , Lee Yi‐Chern , Wu Chen‐I , Lo Li‐Hua , Shiea Jentaie 
Published: September 2007

AbstractIn this study, we discover that hemoglobins (Hb), highly water‐soluble globular proteins that are the most predominant proteins detected by matrix‐assisted laser desorption ionization/time‐of‐flight (MALDI‐TOF) mass spectrometry in blood, can be used as protein biomarkers for fecal occult blood (FOB). Hemoglobins were extracted from the feces with pure water and separated from the solids in feces through centrifugation. Singly charged molecular ions of Hb‐related α chains (theoretical MW: 15 126) and β chains (theoretical MW: 15 867) were detected by MALDI‐TOF operated in linear mode using 4‐hydroxy‐α‐cyanocinnamic acid (α‐CHC) as the matrix (with a volumetric ratio of 1:1). The detection limit of FOB using this method is estimated to be lower than 0.1 µg blood per mg of feces, which is approximately 10 to 100 times lower than that of the conventional chemical approaches. The foods and dietary supplements that commonly interfere with the conventional chemical assays of FOB – such as animal blood food products and tablets containing iron and vitamin C – do not interfere with the detection of Hb biomarkers during MALDI‐TOF analysis. Copyright © 2007 John Wiley & Sons, Ltd.
An ion optics for effective ion detection in single particle mass spectrometry
Authors: Cho Sung‐Woo , Lee Donggeun 
Published: September 2007

AbstractRecently, we reported that significant ion loss occurs prior to detection in conventional single particle mass spectrometry. A more serious type of loss is ion‐kinetic‐energy‐dependent loss. This leads to significant errors in the measured chemical composition of nanoparticles, especially when they have a core‐shell structure. In this paper, a novel ion optics for effective detection of ions generated from a single nanoparticle is designed. Using the commercial software SIMION, the trajectories of ions launched at different speeds inside a single particle mass spectrometer are simulated. The effects of changes are investigated with different repelling plates, Einzel lens additions, and substitutions of the tube electrode between extraction and acceleration grids on the ion flight. The best design was found when assembling the trials in the present condition. It was demonstrated experimentally that the new ion optics works well not only in theory, but also in practice. Copyright © 2007 John Wiley & Sons, Ltd.
Experimental investigation of mass analysis using an island of stability with a quadrupole with 2.0% added octopole field
Authors: Moradian Annie , Douglas D. J. 
Published: September 2007

AbstractWe describe experimental investigations of mass analysis using an island of stability with a linear quadrupole with a 2.0% added octopole field. The island is formed by auxiliary quadrupole excitation. The experiments confirm the results of previous computer simulations (Konenkov et al., J. Am. Soc. Mass Spectrom. 2007; 18: 826–834). With the resolving direct current (dc) applied to the quadrupole so that the Mathieu parameter a > 0, conventional mass analysis with applied radio‐frequency (rf) and dc and no auxiliary excitation is possible. In this case, use of an island of stability yields similar peak shape and resolution. However, with the polarity of the resolving dc reversed, so that a < 0, only very low resolution can be obtained; the added octopole prevents conventional mass analysis. By using a stability island when a < 0, the resolution is substantially improved. In this case the use of an island allows mass analysis under conditions where the added octopole field severely degrades conventional analysis. The experiments also confirm the position of the island predicted by the simulations. Copyright © 2007 John Wiley & Sons, Ltd.
Cross‐layer approach for an air interface of GEO satellite communication networks
Authors: Kota Sastri , Giambene Giovanni , Candio Nico Liberato 
Published: September 2007

AbstractSatellite communications play a significant role in supporting next‐generation IP‐based networks. To deploy state‐of‐the‐art satellite technologies supporting media‐rich applications, efficient utilization of radio resources and end‐to‐end Quality of Service support are mandatory requirements. The study of satellite communication constraints such as attenuation, propagation delays, fading is very critical to support user service level agreements. Adaptive resource management, advanced modulation and coding techniques and congestion control algorithms must be jointly conceived. Transport protocols need to address the impact on end‐to‐end system performance due to lower layer protocols. In this paper, we focus on cross‐layer adaptation and interaction analysis. In particular, we refer to TCP and lower layers in a geostationary‐based network architecture, assuming transport protocol enhancements such as TCP NewReno, SACK, Westwood+ and Hybla. At the physical layer, modulations and coding considered include BPSK and QPSK with convolutional coder/Viterbi decoder. The interest of this study is in evaluating the impact of two different transmission mode selection techniques: one scheme selects between the two modes on the basis of the layer 2 packer error rate performance (non‐cross‐layer method); while, the other technique selects the transmission mode on the basis of the TCP goodput performance (cross‐layer method). Our simulation results demonstrate that the second scheme permits the significant improvement of the end‐to‐end performance. Copyright © 2007 John Wiley & Sons, Ltd.
Experimental verification of optical backhaul links for high‐altitude platform networks: Atmospheric turbulence and downlink availability
Authors: Horwath Joachim , Perlot Nicolas , Knapek Markus , Moll Florian 
Published: September 2007

AbstractOptical backhaul downlinks from high‐altitude platforms (HAPs) are investigated. An experiment demonstrated the advantages of optical links: a small and lightweight terminal with low power consumption was launched to the stratosphere and data transmitted down to a ground station at a rate of 1.25 Gbit/s. Owing to the chosen system parameters and the high budget margin, disturbing turbulence effects did not decrease the link performance.The scientific aspect of the experiment was to study turbulence effects in order to design future systems with higher transmission performance. On the day of the experiment, measured scintillation and wavefront distortions were minimal in the morning. The best atmospheric conditions were observed about 3 h after sunrise with a peak of the atmospheric coherence length r0 at 16 cm. An r0 of 4 cm was measured as the worst case before sunrise and later during the day. This trend could also be observed for power‐ ($ {\sigma _P^2} $) and intensity scintillation index ($ {\sigma _I^2} $). The latter $ {\sigma _I^2} $ changed from 0.28 (best case) to 1.12. For small $ {\sigma _I^2} $, a lognormal intensity probability density function was measured.Apart from the robust intensity modulation scheme with direct detection which was used for the trial, future improved systems could benefit from a coherent transmission scheme. According to the r0 measurements and further simulations on heterodyne efficiency it turned out that the aperture size can be decreased from 40 to 10 cm without any significant change in the link margin.Future stratospheric optical links between HAPs or links from platforms to satellites will not suffer from cloud blockage but it remains an issue for up/downlinks to a ground station. This can be mitigated by ground‐station diversity. Four optical ground stations in the southern part of Europe can lead to an availability of over 98%. The separation distance of the ground stations is about 900 km with a negligible correlation of cloud cover. A change of wavelength from the employed 1.55 to a wavelength around 11‐µm with minimum cloud attenuation would increase the link availability for thin clouds. Copyright © 2007 John Wiley & Sons, Ltd.