bluuebunny/crossref_metadata_2025 huggingface dataset:
Methods for the detection and characterisation of noroviruses associated with outbreaks of gastroenteritis: Outbreaks occurring in the north‐west of England during two norovirus seasons
Authors: Gallimore Chris I. , Green Jonathan , Richards Alison F. , Cotterill Hillary , Curry Alan , Brown David W.G. , Gray Jim J.
Published: April 2004

This article describes the methods used to investigate 407 outbreaks of acute non‐bacterial gastroenteritis occurring in the North‐West of England between January 2000 and July 2001 and suspected to be caused by noroviruses (NV) [Mayo (2002) Arch Virol 147:1655–1663]. These included 319 outbreaks in hospitals and nursing homes and 88 other settings. Eight hundred and seventy‐one faecal samples from 407 outbreaks were tested using electron microscopy (EM), an enzyme‐linked immunosorbent assay (ELISA) specific for Grimsby virus (GRV) capsid antigen and/or by reverse transcriptase‐polymerase chain reaction (RT‐PCR) for NV, allowing the utility of each assay for routine diagnosis to be assessed. Preliminary genomic characterisation of detected strains was performed using the heteroduplex mobility assay (HMA) and DNA sequencing. The results demonstrate the continuing predominance of GII‐4 GRV strain of NV as a cause of outbreaks, particularly in hospital and nursing home settings. Overall, NV were detected in 223/407 (55%) of outbreaks tested. However, a wide range of apparently diverse strains was identified, including several not previously reported. Genomic characterisation revealed clusters of linked outbreaks not recognised previously. J. Med. Virol. 73:280–288, 2004. © 2004 Wiley‐Liss, Inc.
Inhibition of respiratory syncytial virus infection with the CC chemokine RANTES (CCL5)
Authors: Elliott Matthew B. , Tebbey Paul W. , Pryharski Karin S. , Scheuer Catherine A. , Laughlin Todd S. , Hancock Gerald E.
Published: April 2004

Respiratory syncytial virus (RSV) is a major cause of respiratory tract disease in infants, aged adults, and immunosuppressed patients. The only approved medicines for RSV disease are administration of prophylatic antibodies or treatment with a synthetic nucleoside. Both approaches are expensive and the latter is not without risk and of controversial benefit. The present investigation studied whether pharmaceutical or biologic compounds based upon chemokines might be useful in preventing RSV disease. Of interest was RANTES/CCL5, which inhibits infection by HIV strains that use chemokine receptor (CCR)‐5 as co‐receptor. Herein, we report that prior or simultaneous treatment of HEp‐2 cells with recombinant human CCL5 provides dose‐dependent inhibition of infection with RSV. Other recombinant chemokines (MIP‐1α/CCL3, MIP‐1β/CCL4, MCP‐2/CCL8, eotaxin/CCL11, MIP‐1δ/CCL15, stromal cell derived factor (SDF)‐1α/CXCL12) were not inhibitory. The data suggested that CCL5 might inhibit infection by blocking fusion (F) protein–epithelial cell interactions. Infections by mutant RSV strains deleted of small hydrophobic and/or attachment proteins and only expressing F protein in the envelope were inhibited by prior treatment with CCL5 or a biologically inactive N‐terminally modified met‐CCL5. Inhibition was also observed when virus adsorption and treatment with CCL5 were performed at 4°C. Flow cytometry further revealed that epithelial cells were positive for CCR3, but not CCR1 or CCR5. Thus, novel mimetics of CCL5 may be useful prophylatic agents to prevent respiratory tract disease caused by RSV. J. Med. Virol. 73:300–308, 2004. © 2004 Wiley‐Liss, Inc.
NMDA and AMPA receptor expression and cortical neuronal death are associated with p38 in glutamate‐induced excitotoxicity in vivo
Authors: Rivera‐Cervantes M.C. , Torres J. Segura , Feria‐Velasco A. , Armendariz‐Borunda J. , Beas‐Zárate C.
Published: April 2004

Early overstimulation of ionotropic glutamate receptors (iGluRs), such as the N‐methyl‐D‐aspartate (NMDA) and α‐amino‐3‐hydroxy‐5‐methylisoxazole‐4‐propionate (AMPA) receptors, produces excitotoxicity in several brain regions. The molecular composition of those receptors and their regulation by intracellular signaling systems could be determinants in the development of progressive neurodegenerative mechanisms in the central nervous system (CNS). Studies of p38 mitogen‐activated protein kinase (MAPK) activation, morphologic changes including cell number, and the expression of the NR1 and GluR2 subunits, by reverse transcriptase‐PCR were evaluated at early postnatal ages (postnatal day [PD]8–14) in cerebral cortex of rats treated with monosodium glutamate (MSG; 4 mg/g body weight) administered subcutaneously on PD1, 3, 5, and 7. An important increase in p38 activity at PD8 and loss of cortical cell number were observed from PD8–14 in animals treated with MSG, together with significant morphologic changes characterized by cell shrinkage, nuclear hyperchromatism, and cytoplasmic vacuolation. These morphologic changes were prevented by SB203580, an inhibitor of p38 signaling, at PD8–14. No change in cerebral cortex thickness was observed among experimental or control rats. A significant increase in NR1 subunit expression was observed in response to MSG from PD8–14. GluR2 expression increased from PD8–12, but at PD14, its expression was reduced to 54% with respect to controls. SB203580 prevented alone the decreased in GluR2 expression induced by MSG. These results suggest that initial neuronal death (at PD8 and 10) in cerebral cortex may be due to an excessive Ca2+ influx through NMDA receptors, whereas the further damage process could be mediated by AMPA receptors through p38 signaling. This could represent a determinant mechanism to decide whether nerve cells survive or die. © 2004 Wiley‐Liss, Inc.
Hyperpolarization‐activated, cyclic nucleotide‐gated cation channels: Roles in the differential electrophysiological properties of rat primary afferent neurons
Authors: Tu Huiyin , Deng Lunbin , Sun Qian , Yao Lei , Han Ji‐Sheng , Wan You
Published: April 2004

The large, medium‐sized, and small neurons of the dorsal root ganglion (DRG) have different functions in the processing of various senses. Hyperpolarization‐activated, cyclic nucleotide‐gated channels (HCN) contribute greatly to neuronal excitability. In the present study, which used whole‐cell patch clamp techniques and immunohistochemical staining methods, the electrophysiological properties of DRG neurons were systematically compared, and the roles of HCN‐1, ‐2, and ‐4 were examined. The main results were as follows. 1) The large neurons had significantly higher V0.5 values (membrane potential at which the HCN channels were half‐activated) and shorter time constants (τ) than small or medium‐sized DRG neurons. However, large DRG neurons had higher Ih density (HCN neuron current). 2) HCN‐1 was found predominantly, but not exclusively, in large and medium‐sized DRG neurons; HCN‐2 was found in all DRG neurons; and HCN‐4 was poorly visualized in all DRG neurons. HCN‐1 and HCN‐2 were colocalized in large and medium‐sized neurons with immunostaining of adjacent sections. In the dorsal horn of the spinal cord, HCN‐1, HCN‐2, and HCN‐4 were all expressed in laminae I–IV, although HCN‐1 was not detectable in lamina II. 3) Blockade of Ih current in DRG neurons caused a significant decrease in V0.5, resting membrane potential, and repetitive firing number of action potential and a significant increase in time of rising phase of action potential. These results suggest that the different HCN channels in the three types of DRG neurons might contribute to their differential electrophysiological properties. © 2004 Wiley‐Liss, Inc.
Melt Rheological Properties of Branched Polyethylenes Produced with Pd‐ and Ni–Diimine Catalysts
Authors: Ye Zhibin , AlObaidi Fahad , Zhu Shiping
Published: April 2004

Summary: Seven branched polyethylenes differing in chain topology from hyperbranched to linear structure were synthesized with chain walking Pd‐diimine catalyst, [(ArNC(Me)C(Me)NAr) Pd(CH3)(NCMe)]SbF6 (1), and Ni‐diimine catalyst, (ArNC(An)C(An)NAr) NiBr2 (2)/MMAO, respectively. An extensive rheological study, employing steady‐shear, creep‐recovery, and dynamic oscillation tests, was conducted to examine and compare the melt rheological properties of this novel series of polymers. It was found that the change of chain topology dramatically affected the polymer flow behavior, flow activation energy, and dynamic moduli (G′(ω), G″(ω)). The hyperbranched polymers exhibited typical Newtonian flow behavior and extremely low viscosity. The polymers with chain topology intermediate between hyperbranched and linear structures, however, were essentially viscoelastic materials. All the polymers obeyed the time‐temperature superposition and exhibited enhanced flow activation energy (43.8∼57.2 kJ/mol) compared to HDPE and LLDPE. In the terminal region, these polymers had different dependencies of dynamic moduli (G′(ω), G″(ω)) on angular frequency (ω) and different master curves in the log(G′) versus log(G″) plot. The hyperbranched polymer was also blended with more linear samples as a rheology modifier and was found to significantly lower the viscosity of the blends.

Structure of the Pd‐ and Ni‐catalysts used in this study.

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Structure of the Pd‐ and Ni‐catalysts used in this study.
A Detailed On‐Line FT/NIR and 1H NMR Spectroscopic Investigation into Factors Causing Inhibition in Xanthate‐Mediated Vinyl Acetate Polymerization
Authors: Favier Arnaud , Barner‐Kowollik Christopher , Davis Thomas P. , Stenzel Martina H.
Published: April 2004

Summary: Potential sources of inhibition have been investigated via in situ Fourier transform – near infra‐red (FT‐NIR) and off‐line 1H NMR spectroscopy in the RAFT/MADIX bulk polymerization of vinyl acetate (VA) in the presence of an O‐isopropyl xanthate, i.e. methyl (isopropoxycarbonothioyl)sulfanyl acetate. The very high reactivity of the vinyl acetate propagating radical makes it vulnerable to oxygen, by‐products generated during the xanthate synthesis, and stabilizers present as impurities. These impurities induce strong and variable inhibition periods in the polymerization. In addition, the MADIX process, using xanthates as reversible chain transfer agents, has been confirmed to be an efficient method for living VA polymerization. Congruent data are obtained when the monomer consumption with time is followed via both 1H NMR and in situ FT‐NIR spectroscopy. The xanthate‐mediated polymerization of VA exhibits no retardation effects and excellent control of the molecular weight distribution can be achieved, leading to poly(VA) of molecular weights exceeding 50 000 g · mol−1 with relatively low polydispersities.

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When will larger‐sized female models in advertisements be viewed positively? The moderating effects of instructional frame, gender, and need for cognition
Authors: Peck Joann , Loken Barbara
Published: April 2004

A variety of negative consequences for girls and women have been associated with women's and men's viewing unrealistic portrayals of women in advertising. However, research on the positive consequences of presenting larger‐sized women in advertisements, and the conditions under which they are effective, has been lacking. The present research examined such positive effects and found that larger‐sized female models in ads were rated as more attractive when an instructional frame activated nontraditional beliefs (a new women's magazine that features larger‐sized models) than when it activated traditional beliefs (a traditional women's magazine). These effects were more pronounced for women than for men, and particularly for women who scored higher in their need for cognition. The degree to which women generated positive thoughts about themselves in response to the ads tended to correspond with their ratings of increased attractiveness of the models in the ads. Implications of findings for using positive larger‐sized female models in ads are discussed. © 2004 Wiley Periodicals, Inc.
New decay estimates for linear damped wave equations and its application to nonlinear problem
Authors: Ikehata Ryo
Published: April 2004

We present new decay estimates of solutions for the mixed problem of the equation vtt−vxx+vt=0, which has the weighted initial data [v0,v1]∈(H10(0,∞) ∩L1,γ(0,∞)) × (L2(0,∞)∩L1,γ(0,∞)) (for definition of L1,γ(0,∞), see below) satisfying γ∈[0,1]. Similar decay estimates are also derived to the Cauchy problem in ℝN for utt−Δu+ut=0 with the weighted initial data. Finally, these decay estimates can be applied to the one dimensional critical exponent problem for a semilinear damped wave equation on the half line. Copyright © 2004 John Wiley & Sons, Ltd.
A remark on the pressure for the Navier–Stokes flows in 2‐D straight channel with an obstacle
Authors: Morimoto H.
Published: April 2004

Let T=ℝ×(‐1,1) and &ℴ⊂ℝ2 be a smoothly bounded open set, closure of which is contained in T. We consider the stationary Navier–Stokes flows in $\Omega {:=} T \backslash \bar{\scriptstyle{O}}$. In general, the pressure is determined up to a constant. Since Ω has two extremities, we want to know if we can choose the constant same. We study the behaviour of the pressure at the infinity in Ω and give a relation between the velocity and the pressure difference. Copyright © 2004 John Wiley & Sons, Ltd.
The long‐time behaviour of the thermoconvective flow in a porous medium
Authors: Efendiev M. A. , Fuhrmann J. , Zelik S. V.
Published: April 2004

For the Boussinesq approximation of the equations of coupled heat and fluid flow in a porous medium we show that the corresponding system of partial differential equations possesses a global attractor. We give lower and upper bounds of the Hausdorff dimension of the attractor depending on a physical parameter of the system, namely the Rayleigh number of the flow. Numerical experiments confirm the theoretical findings and raise new questions on the structure of the solutions of the system. Copyright © 2004 John Wiley & Sons, Ltd.
MESFET two‐dimensional nonlinear current model extraction for Volterra‐series analysis
Authors: Huang Chien‐Chang , Pai Han‐Ting
Published: April 2004

A two‐dimensional (2D) Taylor‐series coefficient evaluation of MESFET drain currents is presented based on low‐frequency harmonic‐power measurements with associated phase polarities. The formulation is a systematic approach to acquire the general forms for any nonlinear orders. The extraction procedure is performed using a recursive scheme in order to reduce the number of unknowns in each solving process. Simulations and measurements of a two‐tone intermodulation distortion for a MESFET amplifier show the validity of the proposed method. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 461–463, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20171
Calculation of the renal perfusion and glomerular filtration rate from the renal impulse response obtained with MRI
Authors: Hermoye L. , Annet L. , Lemmerling Ph. , Peeters F. , Jamar F. , Gianello P. , Van Huffel S. , Van Beers B.E.
Published: April 2004

The aim of this study was to assess the importance of deconvolution for the calculation of renal perfusion and glomerular filtration rate (GFR) on the basis of concentration–time curves as measured with perfusion MRI. Six rabbits were scanned dynamically after injection of a gadolinium chelate. Concentration–time curves were generated by manually drawing regions of interest in the aorta and the renal cortex. To remove the dependency on the arterial input function, a regularized structured total least‐squares deconvolution algorithm was used to calculate the renal impulse response. This curve was fitted by the sum of two gamma variate functions, corresponding to the passage of the contrast agent in the glomeruli and the proximal convoluted tubules. Tracer kinetics models were applied to these two functions to obtain the renal perfusion and GFR. For comparison, these two parameters were also calculated on the basis of the renal concentration–time curve before deconvolution. The renal perfusion values correlated well (r = 0.9, P = 0.014) with the values calculated by a validated upslope method. The GFR values correlated well (r = 0.9, P = 0.014) with the values obtained from the clearance of 51Cr‐EDTA. A comparison of the values obtained with and without deconvolution demonstrated the necessity of deconvolution. Magn Reson Med 51:1017–1025, 2004. © 2004 Wiley‐Liss, Inc.
Quantitative description of proton exchange processes between water and endogenous and exogenous agents for WEX, CEST, and APT experiments
Authors: Zhou Jinyuan , Wilson David A. , Sun Phillip Zhe , Klaus Judith A. , van Zijl Peter C.M.
Published: April 2004

The proton exchange processes between water and solutes containing exchangeable protons have recently become of interest for monitoring pH effects, detecting cellular mobile proteins and peptides, and enhancing the detection sensitivity of various low‐concentration endogenous and exogenous species. In this work, the analytic expressions for water exchange (WEX) filter spectroscopy, chemical exchange‐dependent saturation transfer (CEST), and amide proton transfer (APT) experiments are derived by the use of Bloch equations with exchange terms. The effects of the initial states for the system, the difference between a steady state and a saturation state, and the relative contributions of the forward and backward exchange processes are discussed. The theory, in combination with numerical calculations, provides a useful tool for designing experimental schemes and assessing magnetization transfer (MT) processes between water protons and solvent‐exchangeable protons. As an example, the case of endogenous amide proton exchange in the rat brain at 4.7 T is analyzed in detail. Magn Reson Med 51:945–952, 2004. © 2004 Wiley‐Liss, Inc.
Reduced RF power without blurring: Correcting for modulation of refocusing flip angle in FSE sequences
Authors: Busse Reed F.
Published: April 2004

In order to reduce the RF power deposition of fast spin echo sequences operated at high field strength, the flip angles of the refocusing pulse train are varied from pulse to pulse using a modulated angle refocusing train method. The technique employs high flip angle pulses prior to sampling the center of k‐space in order to preserve T2 contrast, low flip angles after sampling the center of k‐space to reduce power and prolong relaxation, and a smooth transition between the high and low flip angle regimes in order to maintain the pseudosteady‐state, maximizing signal and avoiding artifact‐inducing oscillations. An analytical expression is used to predict and correct for the flip angle dependence of the signal, thus eliminating any deleterious effects of flip angle modulation on the point spread function. Analysis of resolution and SNR were performed in simulation and phantom studies. In human imaging studies, it is shown that RF energy deposition per slice in a single‐shot fast spin echo application can be reduced by up to 75%, making the sequence as practical at 3 T as it is has been at 1.5 T. Magn Reson Med 51:1031–1037, 2004. © 2004 Wiley‐Liss, Inc.
In vivo precision of quantitative shoulder cartilage measurements, and changes after spinal cord injury
Authors: Vanwanseele B. , Eckstein F. , Hadwighorst H. , Knecht H. , Spaepen A. , Stüssi E.
Published: April 2004

Recent advances in MRI have enabled the quantitative assessment of articular cartilage morphology in human joints. In this study, we tested the hypothesis that the precision of quantitative shoulder cartilage measurements is sufficient to detect changes between and within patients, and that shoulder cartilage thickness in paraplegic patients increases due to increased loading. We imaged the shoulders of seven healthy volunteers four times using a coronal 3D, fat‐suppressed, gradient‐echo sequence. The humeral head cartilage in seven paraplegic patients was evaluated soon after injury and 1 year post injury. A precision of 4.5% (root mean square (RMS) average coefficient of variation (CV) %) was found for shoulder cartilage thickness measurements in the humeral head. Whereas a significant decrease of cartilage thickness (−11%, P < 0.05) was observed in the knee, there was no significant change in articular cartilage thickness in the shoulder (−1.1%). Our data show, for the first time, that articular cartilage of the humeral head can be quantified with acceptable precision in vivo. It was demonstrated that, in contrast to the knee, the articular cartilage morphology of the humeral head changes very little (i.e., there is no significant increase or decrease in thickness) after spinal cord injury (SCI). Magn Reson Med 51:1026–1030, 2004. © 2004 Wiley‐Liss, Inc.
Association of spinal and bulbar muscular atrophy with myotonic dystrophy type 1
Authors: Jinnai Kenji , Nishimoto Keisuke , Itoh Kyoko , Hashimoto Kozo , Takahashi Keiichi
Published: April 2004

A man with spinal and bulbar muscular atrophy (SBMA) had a short (CTG)n expansion in the myotonic dystrophy protein kinase gene as well as (CAG)n expansion in the androgen receptor gene in leukocytes. The patient had the characteristic clinical findings of SBMA, but none of myotonic dystrophy type 1 (DM1). All of his three children (a son and two daughters) had the DM1 phenotype with long (CTG)n expansions. The daughters also had heterozygous long (CAG)n expansions. Postmortem examination of the patient revealed the characteristic pathological changes of SBMA as well as muscle degeneration compatible with DM1. Gene analysis of the organs disclosed unstable long expansions of the (CTG)n repeats, in contrast to the stable (CAG)n expansions. We have assumed that SBMA and DM1 developed independently in our patient, but cannot exclude the possibility that interactive gene effects increased somatic instability. Muscle Nerve 29: 729–733, 2004
Canine inflammatory myopathy: Analysis of cellular infiltrates
Authors: Pumarola Marti , Moore Peter F. , Shelton G. Diane
Published: April 2004

Inflammatory myopathies (IMs) occur relatively frequently in dogs, and, with the exception of masticatory muscle myositis (MMM), have not been characterized. This study analyzed the distribution and types of cellular infiltrates in 21 cases of generalized IM, 3 cases of focal IM (MMM), and 1 case with features of both generalized and focal IM, using a panel of monoclonal antibodies to cell surface markers. In generalized IM, mononuclear cells showed an endomysial and perimysial distribution with invasion of non‐necrotic fibers similar to human IM. T lymphocytes with T‐cell receptor (TCR)αβ predominated. Distinct differences were seen in MMM including prominent B‐cell infiltration, dendritic cells and macrophages in greater numbers than T cells, and numerous T cells with TCRγδ. Thus, generalized IM and MMM appear to be distinct diseases with different mechanisms. Canine generalized IM may be an important animal model for human IM. Muscle Nerve 29: 782–789, 2004
Comparative behavior of polybutadiene and polynorbornene‐based latices prepared by dispersion ring‐opening metathesis polymerization with a poly(ethylene oxide) macromonomer
Authors: Chemtob Abraham , Héroguez Valérie , Gnanou Yves
Published: April 2004

This study critically examines the similarities and differences between poly(ethylene oxide) (PEO) stabilized latices of polynorbornene and polybutadiene. Features such as the kinetics of copolymerization of norbornene and cyclooctadiene with a macromonomer of PEO, the particles' size and morphology, the type of copolymer formed, and the stability of these latices were investigated and the results obtained are considered. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2705–2716, 2004
Effects of a brief intervention program for patients with cancer and their partners on feelings of inequity, relationship quality and psychological distress
Authors: Kuijer Roeline G. , Buunk Bram P. , de Jong G. Majella , Ybema Jan F. , Sanderman Robbert
Published: April 2004

When one member of a couple develops a serious illness, the lives of both partners are likely to be affected. Interventions directed at both partners are generally lacking, however. In the present study, a brief counseling program directed at couples confronted with cancer was evaluated. The intervention focused mainly on the exchange of social support and help between both partners and was aimed at restoring perceptions of equity. Couples were randomly assigned to an experimental group or a waiting‐list group. After the intervention, both patients and their partners reported lower levels of perceptions of underinvestment and overbenefit, and higher levels of relationship quality. Moreover, among patients psychological distress decreased after the intervention. These effects were generally maintained until follow‐up three months later. Associations between perceptions of equity and relationship quality and psychological distress were also examined. Copyright © 2003 John Wiley & Sons, Ltd.
Androgen deprivation therapy for prostate cancer: Current status and future prospects
Authors: Miyamoto Hiroshi , Messing Edward M. , Chang Chawnshang
Published: April 2004

Androgens play a major role in promoting the development and progression of prostate cancer. As a result, androgen ablation or blockade of androgen action through the androgen receptor (AR) has been the cornerstone of treatment of advanced prostate cancer. Different strategies involving this hormonal therapy produce a significant clinical response in most of the patients, but most responders eventually lose dependency, resulting in mortality. Thus, whether hormonal therapy contributes to the improvement of overall survival rates, especially in patients with advanced prostate cancer, remains controversial. However, patients with advanced disease clearly have a benefit from androgen deprivation‐based treatment for palliating their symptoms and for improving the quality of their lives. In order to improve overall survival, novel treatment strategies that prolong the androgen‐dependent state and that are useful for androgen‐independent disease based on specific molecular mechanisms need to be identified. © 2004 Wiley‐Liss, Inc.
Density functional theory study of formamide–formamidic acid tautomerization
Authors: Du Dongmei , Fu Aiping , Zhou Zhengyu
Published: April 2004

The mechanism of tautomerization reaction of formamide–formamidic acid in gas phase and in water has been completely investigated in the present study using, density functional theory (DFT) and the second‐order Møller–Plesset perturbation (MP2) method. Large basis sets 6‐311++G(d,p) have been employed to determine the equilibrium structure and vibrational frequencies. Activation energy of the non‐water F → FA reaction is 202.9 kJ/mol at B3LYP/6‐311++G(d,p) level. Extensions to situations in which tautomerization is assisted by neighboring solvent molecule(s) are considered. If a single H2O molecule is considered, three stable structures and transition states of formamide–water complexes are found. If the water locates between the HN group and the CO moiety, the activation energy decreases to 94.5 kJ/mol. If the water locates in other positions, it can cause the activation energy to increase to 2–4 kJ/mol. When two intimate H2O molecules locate between the HN group and the CO moiety, the activation energy decreases to 89.3 kJ/mol. Intimate solvent participation is thus found much more strongly affecting the activation energy than the overall thermodynamics in this case. Finally, the solution phase studies are also carried out using the Onsager reaction field model, with a range of dielectric constants from 2 to 80 at the B3LYP/6‐311++G(d,p) level. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Attitudes toward chemistry among 11th grade students in high schools in Greece
Authors: Salta Katerina , Tzougraki Chryssa
Published: April 2004

The development of valid and reliable instruments for attitudes' measurement has been proven crucial for the quality of research. This study is dealing with the development and validation of an attitude toward chemistry instrument. By using this instrument, 11th grade Greek students' attitudes regarding the difficulty, the interest, the usefulness of chemistry course, and the importance of chemistry were investigated. Gender and study specialization differences in students' attitudes toward chemistry were examined for this population. Report card grades for the chemistry course were used to measure students' achievement in chemistry and its correlation with students' attitudes toward chemistry was explored. © 2004 Wiley Periodicals, Inc. Sci Ed 88:535–547, 2004
Model-checking dense-time Duration Calculus
Authors: Fränzle Martin
Published: April 2004

Since the seminal work of Zhou Chaochen, M. R. Hansen, and P. Sestoft on decidability of dense-time Duration Calculus [ZHS93] it is well known that decidable fragments of Duration Calculus can only be obtained through withdrawal of much of the interesting vocabulary of this logic. While this was formerly taken as an indication that key-press verification of implementations with respect to elaborate Duration Calculus specifications were also impossible, we show that the model property is well decidable for
realistic
designs which feature natural constraints on their switching dynamics.

The key issue is that the classical undecidability results rely on a notion of validity of a formula that refers to a class of models which is considerably richer than the possible behaviours of actual embedded real-time systems: that of finitely variable trajectories. By analysing two suitably sparser model classes we obtain model-checking procedures for rich subsets of Duration Calculus. Together with undecidability results also obtained, this sheds light upon the exact borderline between decidability and undecidability of Duration Calculi and related logics.
Identification of chloride intracellular channel proteins in spermatozoa
Authors: Myers Kimberley , Somanath Payaningal R. , Berryman Mark , Vijayaraghavan Srinivasan
Published: April 2004

We have identified for the first time the presence of chloride intracellular channel (CLIC) proteins in bovine epididymal spermatozoa. CLIC1 was discovered during microsequencing of proteins that co‐purified with protein phosphatase 1, PP1γ2, in sperm extracts. In addition to CLIC1, Western blot showed that two additional CLIC family members, CLIC4 and CLIC5, are also present in spermatozoa. CLIC fusion proteins, GST‐CLIC1, GST‐CLIC4 and GST‐CLIC5, were all able to bind to PP1γ2 in sperm extracts during pull‐down assays. Immunofluorescence microscopy revealed that each of the three isoforms occupies a distinct location within the cell. Given that PP1γ2 is a key enzyme regulating sperm motility, PP1γ2‐binding proteins, such as the CLIC proteins, are likely to play significant roles in sperm function.
Cationic oligopeptide‐mediated delivery of dsRNA for post‐transcriptional gene silencing in plant cells
Authors: Unnamalai Narayanan , Kang Bong Gu , Lee Woo Sung
Published: April 2004

We have used cationic oligopeptide polyarginine‐12mer (POA) to deliver double‐stranded RNA (dsRNA), prepared in vitro, to tobacco (Nicotiana tabacum) suspension cells. POA interacts electrostatically with dsRNA to form a complex. When dsRNA for the GUS or NPTII gene was delivered into cells carrying the same genes, the corresponding mRNA was degraded. Using RNase protection assay we were able to detect 21‐bp small interfering RNA in dsRNA/POA‐treated cells. These results demonstrate that POA can be used to deliver dsRNA to induce post‐transcriptional gene silencing in plant cells.
Use of a Nonablative Radiofrequency Device to Rejuvenate the Upper One‐Third of the Face
Authors: Bassichis Benjamin A. , Dayan Steven , Thomas J. Regan
Published: April 2004

OBJECTIVE

To evaluate the use of the ThermaCool TC nonablative radiofrequency device for rejuvenation of the upper one‐third of the face, as determined by brow elevation.

STUDY DESIGN AND SETTING

Twenty‐four patients in a facial plastic surgery office were treated with the nonablative radiofrequency device. The patients had pretreatment photos, in‐office procedure, and follow‐up photos. Brow elevation measurements were used to gauge efficacy of the procedure. These results were compared to an untreated, control group of 12 patients.

RESULTS

Compared to the control group, the post‐treatment measurements were improved (P < 0.05). The post‐treatment measurements were also improved from pretreatment baseline (P < 0.05). Subjective results obtained from patient satisfaction questionnaires did not correlate to the objective data. The data also showed that improvement in brow elevation was not uniform in each patient.

CONCLUSION

The ThermaCool TC nonablative radiofrequency device for in‐office rejuvenation of the upper one‐third of the face procedure does provide brow elevation in a majority of patients; however, the majority of the study patients did not perceive benefit from the procedure. Patient satisfaction in facial plastic surgery must be an important part of the decision of whether or not to introduce a new device into a practice setting. (Otolaryngol Head Neck Surg 2004;130:397–406.)
Treatment of Solid Sarcomas in Immunocompetent Mice With Novel, Oncolytic Herpes Simplex Viruses
Authors: Sugiura Saiko , Goshima Fumi , Takakuwa Hiroki , Sata Tetsutaro , Nakashima Tsutomu , Nishiyama Yukihiro
Published: April 2004

OBJECTIVE

Attenuated, replication‐competent herpes simplex viruses (HSVs) have shown promise as antitumor agents for cancer therapy. In this study, we sought to develop a novel type of oncolytic HSV with more potent antitumor activity for use in localized malignant tumors.

STUDY DESIGN

A new, attenuated multimutated HSV (termed HL) was developed, and then a highly metastatic murine fibrosarcoma cell line, NfSa Y83, was injected into the necks or flanks of immuno‐competent C3H mice. The mice were treated with attenuated HSV mutants by intratumoral injection, and antitumor efficacy was assessed by measuring tumor dimensions and overall survival rates.

RESULTS

Treatment with intratumoral injection of HL resulted in marked regression of tumors. In fact, roughly 75% of flank tumors and 50% of neck tumors were completely eradicated.

CONCLUSION

A novel type of attenuated HSV recombinant HL demonstrated a remarkable antitumor efficacy in a localized tumor model in mice. (Otolaryngol Head Neck Surg 2004;130:470‐8.)
A modeling study of ionospheric conductivities in the high‐latitude electrojet regions
Authors: Zhang Bei‐Chen , Kamide Y. , Liu Rui‐Yuan , Shinagawa H. , Iwamasa K.
Published: April 2004

It is important to accurately determine the ionospheric conductivities for a better estimation of energy deposition in the upper atmosphere, particularly at high latitudes. It is a common practice to assume that enhancements in the conductivities are caused by solar radiation and particle precipitation, which can be regarded as external origins. However, little attention has been paid to effects caused by the presence of electrojet currents themselves. We call this effect an internal origin for influencing the ionospheric conductivities. The presence of electrojet current changes the conductivities, and, in turn, the already changed conductivities modify the current systems. That is, a feedback process is expected to take place in magnetosphere‐ionosphere coupling current systems. We use a one‐dimensional high‐latitude ionospheric model in which the continuity equations, as well as momentum and energy equations, are solved self‐consistently to study the conductivities in auroral regions where electrojets exist. The heating effect from the Farley‐Buneman instability, which possibly occurs in the electrojet regions, is considered. Electrojet‐related joule heating and frictional heating are also taken into account. Thermal processes are analyzed in response to the electrojet current. As a result of changes in the thermal structure, we demonstrate the response of the conductivities due to changes in the chemical reaction rate, which results in a higher electron density. The response of altitude profiles of the conductivities is determined by changes in the collision frequency of ions and electrons with neutral components, while an enhancement in the conductance is mainly caused by the electron density. The results show that both the Hall and Pedersen conductances, i.e., the height‐integrated conductivities, increase significantly. The ratio between Hall and Pedersen conductances also changes considerably.
On the sources of bias in aerosol optical depth retrieval in the UV range
Authors: Arola Antti , Koskela Tapani
Published: April 2004

In this paper we discuss and evaluate the systematic sources of bias in aerosol optical depth (AOD) values in the UV range due to (1) the entrance of diffuse light into the finite field of view, (2) diurnal atmospheric changes of ozone under urban conditions, (3) the influence of omitting the effect of NO2 absorption, and (4) stray light of a single monochromator. These error sources have been neglected before in Brewer AOD retrieval. However, if these bias estimates are added together, it appears likely that the main reason for the recent results, that is, an AOD wavelength dependency that is in contradiction to the Ångstrom law, lies in the omitted sources of systematic error in the AOD retrieval. For instance, the estimated negative bias in AOD difference between 306.3 and 320.1 nm is ∼0.0772, while between 310.1 and 320.1 nm it is ∼0.0346. If the true Ångstrom α was 1 and the AOD at 320.1 was 0.5, then the actual difference between 306.3 and 320.1 nm would be positive and equal to 0.022, while between 310.1 and 320.1 nm it would be 0.016. Therefore the neglected source of bias can mask this difference and result in a negative Ångstrom exponent (AE) value. In addition to these sources of bias, we also discuss other potential sources of uncertainty that have been previously neglected.
The use of foraminifera as a record of the past neodymium isotope composition of seawater
Authors: Vance Derek , Scrivner Adam E. , Beney Patricia , Staubwasser Michael , Henderson Gideon M. , Slowey Niall C.
Published: April 2004

We present new isotopic data for sedimentary planktonic foraminifera, as well as for potential water column and sedimentary sources of neodymium (Nd), which confirm that the isotopic composition of the foraminifera is the same as surface seawater and very different from deep water and sedimentary Nd. The faithfulness with which sedimentary foraminifera record the isotopic signature of surface seawater Nd is difficult to explain given their variable and high Nd/Ca ratios, ratios that are often sedimentary foraminifera, ratios that are often much higher than is plausible for direct incorporation within the calcite structure. We present further data that demonstrate a similarly large range in Nd/Ca ratios in plankton tow foraminifera, a range that may be controlled by redox conditions in the water column. Cleaning experiments reveal, in common with earlier work, that large amounts of Nd are released by cleaning with both hydrazine and diethylene triamine penta‐acetic acid, but that the Nd released at each step is of surface origin. While further detailed studies are required to verify the exact location of the surface isotopic signature and the key controls on foraminiferal Nd isotope systematics, these new data place the use of planktonic foraminifera as recorders of surface water Nd isotope ratios, and thus of variations in the past supply of Nd to the oceans from the continents via weathering and erosion, on a reasonably sure footing.
Calibration of active antenna arrays using a sky brightness model
Authors: Rogers Alan E. E. , Pratap Preethi , Kratzenberg Eric , Diaz Marcos A.
Published: April 2004

Low‐frequency arrays (120–400 MHz) can be calibrated using a sky model based on sky maps. For a single antenna the variation of measured power with the Earth's rotation is needed to separate receiver gain and noise temperature. For an array an instantaneous calibration can be made using normalized correlations or normalized beam power for which the receiver gain cancels out. Examples of the sky model for various antenna orientations are shown along with measured data used to perform a calibration. The effects of unmodeled mutual coupling of the received signals and receiver noise on the calibration method are analyzed and are found to result in errors of only a few percent in an array of 5 × 5 crossed dipoles designed to observe the deuterium line at 327 MHz.
Control of the CDPethanolamine pathway in mammalian cells: effect of CTP:phosphoethanolamine cytidylyltransferase overexpression and the amount of intracellular diacylglycerol
Authors: BLEIJERVELD Onno B. , KLEIN Wil , VAANDRAGER Arie B. , HELMS J. Bernd , HOUWELING Martin
Published: April 2004

For an insight regarding the control of PtdEtn (phosphatidylethanolamine) synthesis via the CDPethanolamine pathway, rat liver cDNA encoding ECT (CTP:phosphoethanolamine cytidylyltransferase) was transiently or stably transfected in Chinese-hamster ovary cells and a rat liver-derived cell line (McA-RH7777), resulting in a maximum of 26- and 4-fold increase in specific activity of ECT respectively. However, no effect of ECT overexpression on the rate of [3H]ethanolamine incorporation into PtdEtn was detected in both cell lines. This was explored further in cells overexpressing four times ECT activity (McA-ECT1). The rate of PtdEtn breakdown and PtdEtn mass were not changed in McA-ECT1 cells in comparison with control-transfected cells. Instead, an accumulation of CDPethanolamine (label and mass) was observed, suggesting that in McA-ECT1 cells the ethanolaminephosphotransferase-catalysed reaction became rate-limiting. However, overexpression of the human choline/ethanolaminephosphotransferase in McA-ECT1 and control-transfected cells had no effect on PtdEtn synthesis. To investigate whether the availability of DAG (diacylglycerol) limited PtdEtn synthesis in these cells, intracellular DAG levels were increased using PMA or phospholipase C. Exposure of cells to PMA or phospholipase C stimulated PtdEtn synthesis and this effect was much more pronounced in McA-ECT1 than in control-transfected cells. In line with this, the DAG produced after PMA exposure was consumed more rapidly in McA-ECT1 cells and the CDPethanolamine level decreased accordingly. In conclusion, our results suggest that the supply of CDPethanolamine, via the expression level of ECT, is an important factor governing the rate of PtdEtn biosynthesis in mammalian cells, under the condition that the amount of DAG is not limiting.
Different subcellular localization of sulphotransferase 2B1b in human placenta and prostate
Authors: HE Dongning , MELOCHE Connie A. , DUMAS Nicole A. , FROST Andra R. , FALANY Charles N.
Published: April 2004

The human hydroxysteroid SULT (sulphotransferase) 2B1 subfamily consists of two isoforms, SULT2B1a and SULT2B1b. These two isoenzymes are transcribed from the same gene by alternative splicing of their first exons and share 94% amino acid sequence identity. The SULT2B1 isoforms are highly selective for the sulphation of 3β-hydroxysteroids. Immunoblot analysis of SULT2B1 expression in several human tissues indicates the presence of only SULT2B1b protein. Immunoreactive SULT2B1b protein was detected in human prostate, skin, placenta and lung tissue. SULT2B1b mRNA expression was detected in RNA isolated from term placenta, normal prostate, prostate carcinoma, benign prostate hyperplasia, LNCaP prostate cancer cells, breast cancer specimens and MCF-7 breast cancer cells. Immunohistochemical localization of SULT2B1b, in terms placental and prostate tissues, detected it in nuclei of placental syncytiotrophoblasts and cytoplasm of epithelial cells in prostate tissues. Immunoreactive and catalytically active SULT2B1b was identified in nuclei isolated from term human placenta. Also SULT2B1b was capable of translocating to nuclei in BeWo placental cells after stable transfection and differentiation. In contrast, immunohistochemical analysis of human prostate showed only cytosolic localization of SULT2B1b in the basal and luminal prostate epithelial cells. SULT2B1b was not detected in isolated nuclei from LNCaP prostate cancer cells but was present in the cytosolic fraction. Differential subcellular localization of SULT2B1b in prostate and placenta suggests that SULT2B1b may be differentially regulated and have different physiological functions in these two hormonally responsive human tissues.
Rhesus monkey gastric mucins: oligomeric structure, glycoforms and Helicobacter pylori binding
Authors: LINDÉN Sara , BORÉN Thomas , DUBOIS André , CARLSTEDT Ingemar
Published: April 2004

Mucins isolated from the stomach of Rhesus monkey are oligomeric glycoproteins with a similar mass, density, glycoform profile and tissue localization as human MUC5AC and MUC6. Antibodies raised against the human mucins recognize those from monkey, which thus appear to be orthologous to those from human beings. Rhesus monkey muc5ac and muc6 are produced by the gastric-surface epithelium and glands respectively, and occur as three distinct glycoforms. The mucins are substituted with the histo blood-group antigens B, Lea (Lewis a), Leb, Lex, Ley, H-type-2, the Tn-antigen, the T-antigen, the sialyl-Lex and sialyl-Lea structures, and the expression of these determinants varies between individuals. At neutral pH, Helicobacter pylori strains expressing BabA (blood-group antigen-binding adhesin) bind Rhesus monkey gastric mucins via the Leb or H-type-1 structures, apparently on muc5ac, as well as on a smaller putative mucin, and binding is inhibited by Leb or H-type-1 conjugates. A SabA (sialic acid-binding adhesin)-positive H. pylori mutant binds to sialyl-Lex-positive mucins to a smaller extent compared with the BabA-positive strains. At acidic pH, the microbe binds to mucins substituted by sialylated structures such as sialyl-Lex and sialylated type-2 core, and this binding is inhibited by DNA and dextran sulphate. Thus mucin–H. pylori binding occurs via at least three different mechanisms: (1) BabA-dependent binding to Leb and related structures, (2) SabA-dependent binding to sialyl-Lex and (3) binding through a charge-mediated mechanism to sialylated structures at low pH values.
Location of promoter elements necessary and sufficient to direct testis-specific expression of the Hst70/Hsp70.2 gene
Authors: ŚCIEGLIŃSKA Dorota , VYDRA Natallia , KRAWCZYK Zdzisław , WIDŁAK Wiesława
Published: April 2004

The rat Hst70 gene and its mouse counterpart Hsp70.2 are expressed specifically in pachytene primary spermatocytes and spermatids. Here we demonstrate that a 165 bp fragment of the Hst70 gene promoter, containing the T1 transcription start site region, entire exon 1 and 42 bp 5´ region of the intron, is sufficient to drive testis-specific expression of the chloramphenicol acetyltransferase reporter gene in transgenic mice with the same developmentally regulated pattern as the endogenous Hsp70.2 gene. We show further that high-level tissue-specific gene expression requires additional sequences localized upstream of the T2 transcription start site. Electrophoretic mobility-shift assay analysis revealed that only testes of juvenile rats, when Hst70 gene expression is repressed, contain proteins that specifically bind to the Oct (octamer) sequence localized directly downstream of the T1 site.