bluuebunny/crossref_metadata_2025_split huggingface dataset:
Posttraining intrahippocampal infusion of a protein kinase AII inhibitor impairs spatial memory retention in rats
Authors: Sharifzadeh Mohammad , Sharifzadeh Kurdistan , Naghdi Nasser , Ghahremani Mohammad H. , Roghani Ali 
Published: January 2005

AbstractThe role of protein kinase AII (PKA II) in spatial memory retention in male rats and its regulation of cholinergic gene expression were explored through the effects of intrahippocampal infusion of H‐89, a selective PKA II inhibitor. Alterations in escape latency, travel distance, and swimming speed in a Morris water maze were measured. Animals were trained for 3 days; each day included two blocks, and each block contained four trials. Stereotaxic surgery was employed for the infusions after the last trial on the third day of training, and the animals were tested 48 hr after surgery. Bilateral intrahippocampal infusion of H‐89 (2.5 or 5 μM) into the CA1 region generated significant alterations in escape latency and traveled distance but not swimming speed. The response was fairly dose dependent, and the maximal effect was obtained with 5 μM H‐89. After behavioral testing, several of the infused animals were transcardially perfused and their brains removed. Brain tissue sections from these rats were subjected to immunohistochemical staining analysis with anticholine acetyltransferase (ChAT) antibodies. These analyses indicated that 5 μM H‐89 infusions qualitatively reduced the density of ChAT‐containing cholinergic nerve terminals in the dorsal hippocampus. The intrahippocampal infusions with 5 μM H‐89 also caused an apparent reduction in the number of ChAT‐containing neurons in the medial septum. Our results suggest that PKA II is involved in regulation of cholinergic gene expression and plays an important role in spatial memory retention in rats. © 2004 Wiley‐Liss, Inc.
Weather regimes and their connection to the winter rainfall in Portugal
Authors: Santos J.A. , Corte‐Real J. , Leite S.M. 
Published: January 2005

AbstractWintertime rainfall over Portugal is strongly coupled with the large‐scale atmospheric flow in the Euro‐Atlantic sector. A K‐means cluster analysis, on the space spanned by a subset of the empirical orthogonal functions of the daily mean sea‐level pressure fields, is performed aiming to isolate the weather regimes responsible for the interannual variability of the winter precipitation. Each daily circulation pattern is keyed to a set of five weather regimes (C, W, NAO−, NAO+ and E). The dynamical structure of each regime substantiates the statistical properties of the respective rainfall distribution and validates the clustering technique. The C regime is related to low‐pressure systems over the North Atlantic that induce southwesterly and westerly moist winds over the country. The W regime is characterized by westerly disturbed weather associated with low‐pressure systems mainly located over northern Europe. The NAO− regime is manifested by weak low‐pressure systems near Portugal. The NAO+ regime corresponds to a well‐developed Azores high with generally settled and dry weather conditions. Finally, the E regime is related to anomalous strong easterly winds and rather dry conditions. Although the variability in the frequencies of occurrence of the C and NAO− regimes is largely dominant in the interannual variability of the winter rainfall throughout Portugal, the C regime is particularly meaningful over northern Portugal and the NAO− regime acquires higher relevance over southern Portugal. The inclusion of the W regime improves the description of the variability over northern and central Portugal. Dry weather conditions prevail in both the NAO+ and E regimes, with hardly any exceptions. The occurrence of the NAO+ and the NAO− regimes is also strongly coupled with the North Atlantic oscillation. Copyright © 2005 Royal Meteorological Society
Recent temporal and spatial temperature changes in Egypt
Authors: Domroes Manfred , El‐Tantawi Attia 
Published: January 2005

AbstractIn order to detect and to estimate trends of temperature change in Egypt, trend analyses applying the least‐squares method and the non‐parametric Mann–Kendall test for trends were carried out at six stations for the period 1941–2000 (60 years), and at nine stations for the period 1971–2000 (30 years).According to the trend computations for the period 1941–2000, variable temperature trends over time and space have been observed. Decreasing trends of the mean annual temperature were observed in northern Egypt and (weakly) increasing trends in southern Egypt. Seasonally, positive trends prevailed in summer compared with negative trends in winter. For the recent period, 1971–2000, positive trends were computed for the mean annual and mean minimum temperatures at all stations except Port Said in northern Egypt, where the annual trend was weakly negative. The mean maximum temperature trends were, however, negative at most stations. Seasonally, a definite trend of warming occurred in summer, in contrast to the observations of a global temperature increase in winter.A principal component analysis was applied to compute the all‐Egypt temperature trends. For the observation period, 1941–2000, decreasing trends were shown for annual, maximum, winter and autumn temperatures and increasing trends for minimum, winter and spring temperatures. For the recent period, 1971–2000, all trends were positive except maximum temperature. Copyright © 2005 Royal Meteorological Society
1.70 Å X‐ray structure of human apo kallikrein 1: Structural changes upon peptide inhibitor/substrate binding
Authors: Laxmikanthan Gurunathan , Blaber Sachiko I. , Bernett Matthew J. , Scarisbrick Isobel A. , Juliano Maria Aparecida , Blaber Michael 
Published: January 2005

AbstractHuman kallikreins are serine proteases that comprise a recently identified large and closely related 15‐member family. The kallikreins include both regulatory‐ and degradative‐type proteases, impacting a variety of physiological processes including regulation of blood pressure, neuronal health, and the inflammatory response. While the function of the majority of the kallikreins remains to be elucidated, two members are useful biomarkers for prostate cancer and several others are potentially useful biomarkers for breast cancer, Alzheimer's, and Parkinson's disease. Human tissue kallikrein (human K1) is the best functionally characterized member of this family, and is known to play an important role in blood pressure regulation. As part of this function, human K1 exhibits unique dual‐substrate specificity in hydrolyzing low molecular weight kininogen between both Arg‐Ser and Met‐Lys sequences. We report the X‐ray crystal structure of mature, active recombinant human apo K1 at 1.70 Å resolution. The active site exhibits structural features intermediate between that of apo and pro forms of known kallikrein structures. The S2 to S2′ pockets demonstrate a variety of conformational changes in comparison to the porcine homolog of K1 in complex with peptide inhibitors, including the displacement of an extensive solvent network. These results indicate that the binding of a peptide substrate contributes to a structural rearrangement of the active‐site Ser 195 resulting in a catalytically competent juxtaposition with the active‐site His 57. The solvent networks within the S1 and S1′ pockets suggest how the Arg‐Ser and Met‐Lys dual substrate specificity of human K1 is accommodated. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Role of trehalose and heat in the structure of the C‐terminal activation domain of the heat shock transcription factor
Authors: Bulman Amanda L. , Nelson Hillary C.M. 
Published: January 2005

AbstractThe heat shock transcription factor (HSF) is the primary transcriptional regulator of the heat shock response in eukaryotes. Saccharomyces cerevisiae HSF1 has two functional transcriptional activation domains, located N‐ and C‐terminal to the central core of the protein. These activation domains have a low level of transcriptional activity prior to stress, but they acquire a high level of transcriptional activity in response to stresses such as heat. Previous studies on the N‐terminal activation domain have shown that it can be completely disordered.1 In contrast, we show that the C‐terminal activation domain of S. cerevisiae HSF1 does contain a certain amount of secondary structure as measured by circular dichroism (CD) and protease resistance. The α‐helical content of the domain can be increased by the addition of the disaccharide trehalose but not by sucrose. Trehalose, but not sucrose, causes a blue shift in the fluorescence emission spectra, which is suggestive of an increase in tertiary structure. Trehalose, which is known to be a chemical chaperone, also increases proteases' resistance and promotes heat‐induced increases in α‐helicity. The latter is particularly intriguing because of the physiological role of trehalose in yeast. Trehalose levels are increased dramatically after heat shock, and this is thought to protect protein structure prior to the increase of heat shock protein levels. Our results suggest that the dramatic changes in S. cerevisiae HSF1 transcriptional activity in response to stress might be linked to the combined effects of trehalose and elevated temperatures in modifying the overall structure of HSF1's C‐terminal activation domain. Proteins 2005. © 2005 Wiley‐Liss, Inc.
The key role of atom types, reference states, and interaction cutoff radii in the knowledge‐based method: New variational approach
Authors: Ruvinsky A. M. , Kozintsev A. V. 
Published: January 2005

AbstractWe present a variational method to derive knowledge‐based potentials. The method is based on an optimization procedure of objective variables: atom types, reference states, and interaction cutoff radii. We suggest and apply new unsymmetrical reference states. The cutoff radii and atom types are optimized to improve docking accuracy of the corresponding potentials. The atom types are varied along an atom type tree, with 6 root and 49 top atom types, and the set of 18 optimal atom types is obtained. We demonstrate strong dependence between the choice of atom types and the docking accuracy of the potentials derived with these atom types. The averaged root‐mean square deviations (RMSDs) of the ligand docked positions relative to the experimentally determined positions decrease when the elements C, N, O are split into the optimal types. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Prediction of binding modes for ligands in the cytochromes P450 and other heme‐containing proteins
Authors: Kirton Stewart B. , Murray Christopher W. , Verdonk Marcel L. , Taylor Richard D. 
Published: January 2005

AbstractThe cytochromes P450 (P450s) are a family of heme‐containing monooxygenase enzymes involved in a variety of functions, including the metabolism of endogenous and exogenous substances in the human body. During lead optimization, and in drug development, many potential drug candidates are rejected because of the affinity they display for drug‐metabolising P450s. Recently, crystal structures of human enzymes involved in drug metabolism have been determined, significantly augmenting the prospect of using structure‐based design to modulate the binding and metabolizing properties of compounds against P450 proteins. An important step in the application of structure‐based metabolic optimization is the accurate prediction of docking modes in heme binding proteins. In this paper we assess the performance of the docking program GOLD at predicting the binding mode of 45 heme‐containing complexes. We achieved success rates of 64% and 57% for Chemscore and Goldscore respectively; these success rates are significantly lower than the value of 79% observed with both scoring functions for the full GOLD validation set. Re‐parameterization of metal‐acceptor interactions and lipophilicity of planar nitrogen atoms in the scoring functions resulted in a significant increase in the percentage of successful dockings against the heme binding proteins (Chemscore 73%, Goldscore 65%). The modified scoring functions will be useful in docking applications on P450 enzymes and other heme binding proteins. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Energy transfer phenomena in the luminescence of wide band‐gap scintillators
Authors: Nikl M. 
Published: January 2005

AbstractLuminescence and scintillation dynamics can be extensively influenced by the energy transfer processes, which is demonstrated at three selected scintillator materials: PbWO4, Ce‐doped aluminium garnets and PrF3:Ce single crystals. Charge carrier retrapping processes can delay radiative recombination at the luminescence centers in an extended time scale, which makes a substantial part of generated scintillation light technically unexploitable. Correlated measurements based on time‐resolved emission spectroscopy and thermoluminescence are of great help to evaluate these phenomena and to understand their microscopic origin. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electronic and atomic relaxation processes in irradiated cryocrystals
Authors: Savchenko E. V. , Bondybey V. E. 
Published: January 2005

AbstractRelaxation processes and stability of charge centers in preirradiated cryocrystals doped with atomic and molecular species are discussed. The study was performed combining techniques of spectrally resolved thermally stimulated luminescence (TSL), thermally stimulated exoelectron emission (TSEE) and photon‐stimulated exoelectron emission (PSEE). Comparison of the yields of electrons and photons in VUV and visible ranges made it possible to discriminate between reactions of charge carriers and neutral reactive species and find interconnection between atomic and electronic processes of relaxation. The radiative mechanism of electronic relaxation stimulation via an atomic subsystem is verified. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photostimulable defects in nano‐crystallites in fluorozirconate glasses
Authors: Schweizer S. , Spaeth J.‐M. , Secu M. , Edgar A. , Williams G. V. M. 
Published: January 2005

AbstractThe photostimulated luminescence (PSL) from Eu‐doped fluorobromo‐ and fluorochlorozirconate glass‐ceramics is reviewed. The PSL is attributed to the characteristic emission of Eu2+ present in BaX2 (X = Br, Cl) crystallites which form in the glass upon thermal processing. Both the photoluminescence intensity and the PSL efficiency increase with the size of the crystallites in a way that is consistent with a PSL‐inert surface layer surrounding the crystallites. The increasing crystallite sizes also result in decreased optical transparency at the stimulation wavelength due to scattering. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
DFT study of surface reactivity of CX3I (XH and F) with CH2I2 to form CH2CX2 on the Ag(111) surface
Authors: Lin Jyh Shing , Chou Wen‐Chi 
Published: January 2005

AbstractRecently, Chiang's research group successfully carried out the temperature programmed reaction (TPR) spectroscopy under ultrahigh‐vacuum conditions to probe the reaction pathways of adsorbed methyl (CH3(ads)) and trifluoromethyl (CF3(ads)) with coadsorbed methylene (CH2(ads)) via the CH2 insertion reaction, leading to the formation of adsorbed 1,1,1‐trifluoro‐ethyl (CF3CH2(ads)) and ethyl (CH3CH2(ads)) on the Ag(111) surface. Additionally, the authors found it feasible for CF3CH2(ads) to proceed the subsequent β‐fluoride elimination on the Ag(111) surface to produce 1,1 difluoroethylene (CF2CH2(g)) but difficult for CH3CH2(ads) to proceed β‐hydride elimination to form ethylene (CH2CH2(g)) on the Ag(111) surface. To elaborate on this noticeably different reactivity between β‐hydride and β‐fluoride eliminations on the Ag(111) surface we performed total energy calculations based on density functional theory in connection with ultrasoft pseudopotential and generalized gradient spin‐polarized approximation, and partial structural constraint path minimization to establish the energetically more favorable pathways for the CH2 insertion into AgCX3 (XH and F) bonds followed by β–X elimination to generate an isolated CH2CX2(g) on the Ag(111) surface. Following our proposed reaction pathways, namely, the diffusion of the fcc‐hollow site of CX3(ads) toward the bridge site of CH2(ads) through the CH2 insertion and the subsequent β–X elimination to form both isolated CH2CX2(g) and hcp‐hollow site of X(ads) on the Ag(111) surface, our calculated energy barrier for β‐hydride elimination is significantly larger than (∼0.661 eV) that for β‐fluoride elimination. This unusual high‐energy barrier prohibits β‐hydride elimination of CH2CH3(ads) to form an isolated CH2CH2(g) on the Ag(111) surface and explains what we observed from the TPR experimental data. We also attribute this much higher energy barrier to forming a largely distorted seven‐center ring transition state structure with a larger distortion of the AgC(α)H2C(β)H3Ag and a less stable AgH bond on the Ag(111) surface. Finally, our calculated energy barrier for β‐fluoride elimination to form CH2CF2(g) is 0.687 eV, in very good agreement with the experimental data. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Positive and negative ion chemistry of the anesthetic halothane (1‐bromo‐1‐chloro‐2,2,2‐trifluoroethane) in air plasma at atmospheric pressure
Authors: Marotta Ester , Bosa Elisabetta , Scorrano Gianfranco , Paradisi Cristina 
Published: January 2005

AbstractThe ion chemistry of 1‐bromo‐1‐chloro‐2,2,2‐trifluoroethane (the common anesthetic halothane) in air plasma at atmospheric pressure was investigated by atmospheric pressure chemical ionization mass spectrometry (APCI‐MS). The major positive ion observed at low declustering (API interface) energies is the ionized dimer, M+.M, an unexpectedly abundant species which possibly is stabilized by two H‐bonding interactions. At higher energies [MHF]+. and [MBr]+ prevail; the former, corresponding to ionized olefin [ClBrCCF2]+., appears to originate from M+.M and is quite stable towards fragmentation. The latter fragment ion ([MBr]+) and its analogue, [MCl]+, which is also observed though at much lower abundance, are originally ethyl cations +CHXCF3 (X = Br, Cl) which, upon collisional activation, rearrange and fragment to CHFX+ via elimination of CF2. All of the above described ions are also observed in humid air: in addition, the oxygenated ion [ClBrCCFOH]+. also forms in humid air via water addition to [ClBrCCF2]+. and HF elimination, as observed earlier for ionized trichloroethene. In contrast with similar chloro‐ and fluoro‐substituted ethanes, halothane does not react with H3O+ in the APCI plasma, a result confirmed by selected ion APCI triple‐quadrupole (TQ) experiments. Major negative ions formed from halothane in the air plasma are Br− and, to a lesser extent, Cl−, and their complexes with neutral halothane. APCI‐TQ experiments indicated that Br− and Cl− are formed via reaction of halothane with O, O(H2O) and O, possibly via dissociative electron transfer or nucleophilic substitution. Competing proton transfer was also observed in the reaction with O and, at high halothane pressure, also with O(H2O); at lower pressures the molecular anion M−. was observed instead. The other minor anions of the air plasma, NO, N2O and NO, were found to be unreactive towards halothane. Copyright © 2005 John Wiley & Sons, Ltd.
On the formation of conjugated linoleic acid diagnostic ions with acetonitrile chemical ionization tandem mass spectrometry
Authors: Michaud Anthony L. , Lawrence Peter , Adlof Richard , Brenna J. Thomas 
Published: January 2005

AbstractAcetonitrile chemical ionization tandem mass spectrometry has recently been shown to be a rapid method for the identification of double‐bond position and geometry in methyl esters of conjugated linoleic acids (CLAs); however, the structures of intermediate and diagnostic ions and their mechanisms of formation are not known. A mechanism is proposed here in which the m/z 54 ion, (1‐methyleneimino)‐1‐ethenylium (MIE), undergoes nucleophilic attack preferentially by the cis double bond in CLAs with mixed geometry (cis/trans, trans/cis), favoring the observed CC cleavage vinylic to the trans double bond. The [M+54]+ addition product intermediate is consistent with a heterocyclic six‐membered ring resulting from the two‐step addition of MIE to the CLA. Experiments with isotopically labeled CLAs and acetonitrile, and from MS/MS/MS experiments, yield data consistent with this proposal. The proposed mechanism is also consistent with known ion—molecule chemistry in smaller compounds, and explains most phenomena associated with MIE‐CLA ion chemistry. Copyright © 2005 John Wiley & Sons, Ltd.
Quantitative Fourier transform ion cyclotron resonance mass spectrometry—the determination of creatinine by isotope dilution mass spectrometry
Authors: Bristow Tony , Stokes Peter , O'Connor Gavin 
Published: January 2005

AbstractAccurate quantitation has been demonstrated on many different types of mass spectrometer. However, quantitative applications of Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) have been limited. In this study, the quantitative potential of FTICRMS has been investigated using an exact matching isotope dilution method for the determination of creatinine in serum. Creatinine is an important clinical biomarker and its measurement is used as an assessment of renal function. The quantitation of creatinine was selected because a high‐accuracy high‐performance liquid chromatography/mass spectrometry (HPLC/MS) determination using a triple quadrupole mass spectrometer has already been successfully developed in‐house. Therefore, a direct comparison of the quantitative capability of FTICRMS could be made against an established method. The accuracy of the quantitation of creatinine was found to be equivalent to that obtained using LC/MS. However, the expanded measurement uncertainty (k = 2) was larger, at 6%, when using FTICRMS compared with 1% when using HPLC/MS with the triple quadrupole mass spectrometer. Copyright © 2005 John Wiley & Sons, Ltd.
Update on master's genetic counseling training programs: Survey of curriculum content and graduate analysis summary
Authors: Smith Ann C. M. 
Published: January 2005

AbstractThe field of genetic counseling is a recognized specialty in medical genetics with the primary practitioners being masters degree prepared individuals. Since the inception of the first master's degree genetic counseling (MGC) training program in 1969, more than 1000 genetic counselors have graduated from established training programs in United States and Canada. The MGC programs involve a 2‐year academic curriculum of both didactic course work and supervised clinical field work (clinical praticums). A recent survey of 17 existing MGC training programs (16 U.S. and 1 Canadian) reveals that MGC graduates average a total of 1349 actual contact hours (range 854–1952 hours) during their 2‐year degree program course of study. Clinical experience gained through clinical practica accounts for 58% of required coursework, followed by didactic coursework in basic science (21%) and counseling (16%), respectively. A few programs also have requisite laboratory practica, which accounts for 5% of overall content hours. The 17 existing MGC programs produce approximately 100 graduates annually. Although the number of programs has grown since inception of the first MGC program in 1969, the mean number of graduates per program remains fairly constant. By year 2002, the estimated total number of master's degree trained genetic counselors will approach 2200.