bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Chlorine Contents in Geological Survey of Japan Reference Materials by Prompt Gamma Neutron Activation Analysis
Authors: Sano Takashi , Fukuoka Takaaki , Hasenaka Toshiaki
Published: May 2007

We determined chlorine contents in nine GSJ (Geological Survey of Japan) reference materials (JB‐1, 1a, 2, 3; JA‐1, 2, 3; JR‐1, 2) by prompt gamma neutron activation analysis, employing the standard addition method. Pressed powder disks of each reference material were used for neutron irradiation and gammaray measurement, after known quantities (25‐200 μl) of sodium chloride solution were added. The influence of the nearby sodium peak overlap was checked, and fluctuations in the chlorine count rate were corrected using silicon as an internal standard. The slopes of calibration lines for seven reference materials (JB‐1, 2, 3; JA‐1, 2, 3; JR‐2) and SiO2 powders fall within 5% error, and their chlorine values were obtained from the intercepts. Chlorine contents in JB‐1 a and JR‐1 were also determined by using the calibration lines. Our chlorine values ranged from 26.1 to 934 μg g‐1, which agrees well with the previously reported values.
Preparation of a Synthetic Titanite Glass Calibration Material for In Situ Microanalysis by Direct Fusion in Graphite Electrodes: A Preliminary Characterisation by EPMA and LA‐ICP‐MS
Authors: Ødegård Magne , Skår Øyvind , Schiellerup Henrik , Pearson Norman J.
Published: May 2007

This paper describes a technique for the preparation of a titanite (CaTiSiO5) glass calibration material for use in in situ microanalysis of major, minor, and trace elements in geological materials. The starting composition was a titanite matrix doped with minor and trace elements at ∼ 200 μg g‐1. The elements Sc, Y, REEs, Th and U were added in the form of nitrates in solution, and the elements V, Cr, Mn, Fe, Co, Ni, Zr, Nb, Hf and W were added as solid oxides. The synthetic titanite glass was produced by direct fusion by resistance heating in graphite electrodes at 1600‐1700 °C, and quenched in air. Backscattered electron images indicate good homogeneity, with no signs of separate phases or vesicles, and analysis of the major elements Ca, Ti and Si by electron microprobe showed relative standard deviations between 0.5 and 0.7%, based on six independent measurements. Deviations from nominal concentrations for Ca, Si and Ti were measured to ‐1.2, ‐3.3 and ‐0.8%, respectively. The homogeneity of the trace elements in the glass was assessed by LA‐ICP‐MS analyses, using NIST SRM 610, 612 and 616 as external calibrators, and Ca as the internal standard element. Determinations were made both with a quadrupole mass spectrometer and a sector field instrument, and both raster and spot modes of analysis were used. For the majority of doped elements, precision was better than 10%, and relative deviations from nominal values were, with few exceptions, between 5 and 10%.
Chemical Separation and Isotopic Variations of Cu and Zn From Five Geological Reference Materials
Authors: Chapman John B. , Mason Thomas F.D. , Weiss Dominik J. , Coles Barry J. , Wilkinson Jamie J.
Published: May 2007

This paper presents an adapted anion exchange column chemistry protocol which allowed separation of high‐purity fractions of Cu and Zn from geological materials. Isobaric and non‐spectral interferences were virtually eliminated for consequent multiple‐collector ICP‐MS analysis of the isotopic composition of these metals. The procedure achieved ∼ 100% recoveries, thus ensuring the absence of column‐induced isotopic fractionation. By employing these techniques, we report isotopic analyses for Cu and Zn from five geological reference materials: BCR‐027 blende ore (BCR), δ65Cu = 0.52 ± 0.15‰ (n = 10) and δ66Zn = 0.33 ± 0.07‰ (n = 8); BCR‐030 calcined calamine ore (BCR), δ66Zn = ‐0.06 ± 0.09‰ (n = 8); BCR‐1 basalt (USGS), δ66Zn = 0.29 ± 0.12‰ (n = 8); NOD‐P‐1 manganese nodule (USGS), δ65Cu = 0.46 ± 0.08‰ (n = 10) and δ66Zn = 0.78 ± 0.09‰ (n = 9); SU‐1 Cu‐Co ore (CCRMP), δ65Cu = ‐0.018 ± 0.08‰ (n = 10) and δ66Zn = 0.13 ± 0.17‰ (n = 6). All uncertainties are ± 2s; copper isotope ratios are reported relative to NIST SRM‐976, and zinc isotope ratios relative to the Lyon‐group Johnson Matthey metal (batch 3‐0749 L) solution, JMC Zn. These values agree well with the limited data previously published, and with results reported for similar natural sample types. Samples were measured using a GVi IsoProbe MC‐ICP‐MS, based at the Natural History Museum, London. Long‐term measurement reproducibility has been assessed by repeat analyses of both single element and complex matrix samples, and was commonly better than ± 0.07‰ for both δ66Zn and δ65Cu.
Trace Element Analysis of Fused Whole‐Rock Glasses by Laser Ablation‐ICP‐MS and PIXE
Authors: Kurosawa Masanori , Shima Kunihiro , Ishii Satoshi , Sasa Kimikazu
Published: May 2007

The concentrations of fifty trace elements, including relatively volatile elements and transition metal elements, in fused glasses of Geological Survey of Japan rock reference materials GSJ JR‐2, JA‐1, JA‐2, JB‐1a, JB‐3, JGb‐1 and JF‐1 were determined by particle (proton) induced X‐ray emission (PIXE) and laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS). The fused glasses were prepared by rapid fusion and subsequent quenching in welded platinum capsules and were found to be homogeneous for major elements and for trace elements with concentrations of more than 1 μg g‐1 within the observed precision (± 10% mean) on a 70 μm sampling scale. The values obtained by PIXE and LA‐ICP‐MS for the transition elements (Cr, Mn, Fe, Ni and Cu), the relatively volatile elements (Zn, Ga, Rb and Pb) and the refractory elements (Y, Zr, Nb and Th) with concentrations greater than a few μg g‐1 showed good agreement (within 10 % relative difference). The values for almost all the elements detected at concentrations higher than 1 μg g‐1 as determined by LA‐ICP‐MS also agreed well with the reference values (mean relative difference < ± 10%), except for B and Cu. The good agreement confirmed the appropriateness of the NIST SRM 600 series glass calibration reference material for LA‐ICP‐MS analysis of glasses with variable major‐element compositions for almost all elements. The concentrations of Cu in all the samples were lower than the reference values, which was attributed to adsorption of the transition metals onto the platinum capsule during preparation.
Determination of Ti, K, Sm and Gd Values in Geological Survey of Japan Reference Materials by Prompt Gamma Neutron Activation Analysis
Authors: Sano Takashi , Hasenaka Toshiaki , Sawahata Hiroyuki , Fukuoka Takaaki
Published: May 2007

Prompt gamma neutron activation analysis was applied to the determination of the titanium, potassium, samarium and gadolinium contents of nine Geological Survey of Japan (GSJ) reference materials (JB‐1, 1a, 2, 3; JA‐1, 2, 3; JR‐1, 2). Firstly, the values in JB‐1 were determined by the standard addition method: pressed powder disks of JB‐1 were used for neutron irradiation and gamma‐ray measurements, after known quantities of standard reagents had been added. Secondly, the contents of eight other reference materials were determined by comparison methods using JB‐1 as the comparative standard. The precision of analyses were obtained by replicate determinations on these samples. The relative standard deviation was generally less than 5%. For most samples, analysed values agreed well (< 5%) with the recommended values.
Airway hyperresponsiveness, peak flow variability and inflammatory markers in non‐asthmatic subjects with respiratory infections
Authors: Björnsson Eyþór , Lúðvíksdóttir Dóra , Hedenström Hans , Eriksson Britt‐Marie , Högman Marieann , Venge Per , Janson Christer
Published: May 2007

Objective:  The aim of this study was to characterise non‐asthmatic subjects with asthma‐like symptoms during a common cold, particularly in relation to airway hyperresponsiveness (AHR).

Materials and Methods:  Subjects with acute respiratory infections and a group of controls (n = 20 + 20), age 20–65 years, underwent bronchial provocations with methacholine, adenosine and cold air. All were non‐smokers and had no history of asthma or heart disease. Those with infection had asthma‐like symptoms (>2). Measurements of exhaled nitric oxide (eNO), serum levels of eosinophil cationic protein (ECP), eosinophil peroxidase, myeloperoxidase and human neutrophil lipocalin were made at each provocation. A 17‐day symptom and peak flow diary was calculated.

Results:  No differences between the two groups were found, regarding responsiveness to methacholine, adenosine or cold air challenge, as well as the inflammatory markers measured. In the infected group, the mean (standard deviation) ECP was higher in those with AHR to methacholine or cold air [15.7 (6.5) and 11.4 (4.2) µg/L, respectively; P < 0.05]; furthermore, eNO was higher in the infected group [116 (54) and 88 (52) nL/min, respectively; P = 0.055]. The infected group had, at all times, more symptoms and higher peak flow, with a decrease in the symptoms (P = 0.02) and a tendency to change in peak flow variation (P = 0.06).

Conclusion:  AHR does not seem to be the main cause of asthma‐like symptoms in adults with infectious wheezing. Peak flow variation and symptom prevalence during the post‐infection period may imply airway pathology different from AHR.

Please cite this paper as: Björnsson E, Lúdvíksdóttir D, Hedenström H, Eriksson B‐M, Högman M, Venge P and Janson C. Airway hyperresponsiveness, peak flow variability and inflammatory markers in non‐asthmatic subjects with respiratory infections. The Clinical Respiratory Journal 2007;1:42–50.
Immunopathogenesis of hepatitis C virus infection and hepatic fibrosis: New insights into antifibrotic therapy in chronic hepatitis C
Authors: Teixeira Rosângela , Marcos Luis A. , Friedman Scott L.
Published: May 2007

Fibrosis and cirrhosis represent the consequences of a sustained wound‐healing response to chronic liver injury of any cause. Chronic hepatitis C virus (HCV) has emerged as a leading cause of cirrhosis in the USA and throughout the world. HCV may induce fibrogenesis directly by hepatic stellate cell activation or indirectly by promoting oxidative stress and apoptosis of infected cells. The ultimate result of chronic HCV injury is the accumulation of extracellular matrix with high density type I collagen within the subendothelial space of Disse, culminating in cirrhosis with hepatocellular dysfunction. The treatment of hepatitis C with the combination of pegylated interferon and ribavirin is still both problematic and costly, has suboptimal efficacy, serious side effects and a high level of intolerance, and is contraindicated in many patients. Hence, new approaches have assumed greater importance, for which there is an urgent need. The sustained progress in understanding the pathophysiology of hepatic fibrosis in the past two decades has increased the possibility of developing drugs specifically targeting the fibrogenic process. Future efforts should identify genetic markers associated with fibrosis risk in order to tailor the treatment of HCV infection based on genetically regulated pathways of injury and/or fibrosis. Such advances will expand the arsenal to overcome liver fibrosis, particularly in patients with hepatic diseases who have limited treatment options, such as those patients with chronic hepatitis C who have a high risk of fibrosis progression and recurrent HCV disease after liver transplantation.
Clinical and pathological features of a prolonged type of acute intrahepatic cholestasis
Authors: Watanabe Norihito , Takashimizu Shinji , Kojima Seiichiro , Kagawa Tatehiro , Nishizaki Yasuhiro , Mine Tetsuya , Matsuzaki Shohei
Published: May 2007

Aim:  We examined the clinical and pathological features of drug‐induced acute intrahepatic cholestasis (AIC) to elucidate the pathogenesis of prolonged cases.

Methods:  Twenty‐six cases of drug‐induced AIC were divided into prolonged and non‐prolonged groups. Serum bilirubin levels and other biochemical data were compared between the two groups. Biopsy liver specimens were examined by light and electron microscopy. The localization of multidrug resistance protein 2 (MRP2) was immunohistochemically assessed by the Envision technique.

Results:  The causative drugs of four prolonged cases were found to be tiopronin, chlorpromazine and diclofenac. Two of the patients either died or underwent liver transplantation. The maximal total bilirubin levels (35.2 ±> 13.8 mg/dL) were significantly higher and a half‐life of total bilirubin (78.8 ±> 69.6 days) was markedly longer in the prolonged cases, in comparison to the non‐prolonged cases (16.8 ±> 8.1 mg/dL, 22.1 ±> 12.7 days, respectively). The liverbiopsy specimens revealed canalicular cholestasis and a slight degree of lobular inflammation. In the prolonged cases, liver cell injury and cholestasis was marked, and the interlobular bile ducts disappeared in the portal triads. The reaction products of MRP2, recognized on the bile canaliculi in a control liver, were weakened and found in the pericanalicular vesicles in AIC.

Conclusion:  These results indicated disturbances in the canalicular bilirubin transport through MRP2 in the prolonged cases, resulting from severe cholestasis, liver cell injury and vanishing bile ducts. The histological findings of the liver at the acute icteric phase may be important to understand the pathogenesis and to predict the prognosis in AIC.
Excited flux tube from q¯g hybrid mesons
Authors: Buisseret F. , Semay C. , Mathieu V. , Silvestre-Brac B.
Published: May 2007

In the framework of quark models, hybrid mesons are either seen as two-body q¯ systems with an excited flux tube connecting the quark to the antiquark or as three-body q¯g systems including a constituent gluon. In this work we show that, starting from the three-body wave function of the q¯g hybrid meson in which the gluonic degrees of freedom are averaged, the excited flux tube picture emerges as an equivalent q¯ potential. This equivalence between the excited flux tube and the constituent-gluon approach is confirmed for heavy hybrid mesons but, for the first time, it is shown to hold in the light sector too, provided the contribution of the quark dynamics is correctly taken into account.
GROWTH OF SiC SUBSTRATES
Authors: POWELL ADRIAN , JENNY JASON , MULLER STEPHAN , McD. HOBGOOD H. , TSVETKOV VALERI , LENOARD ROBERT , CARTER CALVIN
Published: May 2007

In recent years SiC has metamorphisized from an R&D based materials system to emerge as a key substrate technology for a significant fraction of the world production of green, blue and ultraviolet LEDs. Emerging markets for SiC homoepitaxy include high-power switching devices and microwave devices. Applications for heteroepitaxial GaN-based structures on SiC substrates include lasers and microwave devices. In this paper we review the properties of SiC, assess the current status of substrate and epitaxial growth, and outline our expectations for SiC in the future.
ROUTING LIGHT AT WILL
Authors: ASSANTO GAETANO , PECCIANTI MARCO
Published: May 2007

We present a comprehensive review on the routing of self-confined light-beams in liquid crystals, i.e., generation, propagation and angular steering of self-induced waveguides or spatial solitons in a nonlinear non local dielectric with a large electro-optic response. We describe all-optical routing through soliton-soliton or soliton-beam interactions, as well as voltage-controlled steering in an anisotropic geometry via birefringence or refraction/reflection at a graded interface.
TWO-PHOTON STEREOLITHOGRAPHY
Authors: LEE KWANG-SUP , KIM RAN HEE , PRABHAKARAN PREM , YANG DONG-YOL , LIM TAE WOO , PARK SANG HU
Published: May 2007

Two-photon stereolithography based on photopolymerization provides the ability to fabricate real three-dimensional (3D) microstructures beyond the resolution of focal size. In this paper, our recent research focusing on improvement of spatial resolution in two-photon stereolithography is reviewed. The influence of system and fabrication conditions in relation to the spatial resolution is discussed. For small and low aspect ratio voxels, a minimum power and minimum exposure time (MPMT) scheme is introduced. During the two-photon process, an ascending technique, wherein the truncation amount of volumetric pixels is controlled, can be applied to improve the resolution of two-dimensional patterns. 3D Microfabrication with less than 100 nm resolution can be realized by using the radical quenching effect. After the two-photon process, the resolution of fabricated patterns can be refined to 60 nm by post-processing of plasma ashing.
ELECTRIC FIELD TUNING A SPECTRUM OF NEMATIC LIQUID CRYSTAL LASING WITH THE USE OF A PERIODIC SHADOW MASK
Authors: BLINOV L. M. , LAZAREV V. V. , PALTO S. P. , CIPPARRONE G. , MAZZULLA A. , PAGLIUSI P.
Published: May 2007

Lasing has been observed in the dye-doped isotropic and nematic phases of liquid crystals in a plane layer placed between one substrate with a uniform transparent electrode and another substrate with a system of parallel chromium (nontransparent) electrodes. The latter has a periodicity of 15 μm and plays a double role: (i) in both the phases it operates as a shadow mask providing a spatial modulation of the pump beam and consequently, a gain of the material and (ii) in the nematic phase it additionally creates a Bragg resonator structure with spatial modulation of the refraction index when an electric voltage is applied across the transparent and non-transparent electrodes. The resonator operates at high order Bragg resonance modes of numbers m = 71–79 for three lasing dyes studied. With that simple cell, a voltage induced tuning of the spectral positions of lasing lines over 25 nm has been demonstrated without using holographic or other complicated techniques. The mechanism of the observed phenomenon is discussed using modeling of the liquid crystal reorientation and optical properties in the spatially periodic electric field.
STUDY OF PULSE EVOLUTION AND OPTICAL BISTABILITY UNDER THE INFLUENCE OF CUBIC-QUINTIC NONLINEARITY AND THIRD ORDER DISPERSION
Authors: ROY SAMUDRA , BHADRA SHYAMAL
Published: May 2007

Using the variational method, we examine the evolution of different parameters to characterize an optical pulse propagating in a non-Kerr type medium having cubic-quintic nonlinearity in the vicinity of zero dispersion wavelength. The validity of the derived results is tested by applying different ansatz functions over a critical propagation distance. Furthermore, the results are compared with numerically simulated data generated through the Split Step Fourier beam propagation method, solving the dynamic nonlinear cubic-quintic Schrödinger equation (NLCQSE). Subsequently, the effect of higher order dispersion on optical bistability under cubic-quintic nonlinearity is studied in the framework of our proposed model.
CASCADE OF PHASE SHIFTS FOR NONLINEAR SCHRÖDINGER EQUATIONS
Authors: CARLES RÉMI
Published: May 2007

We consider a semi-classical nonlinear Schrödinger equation. For initial data causing focusing at one point in the linear case, we study a nonlinearity which is super-critical in terms of asymptotic effects near the caustic. We prove the existence of infinitely many phase shifts appearing at the approach of the critical time. This phenomenon is suggested by a formal computation. The rigorous proof shows a quantitatively different asymptotic behavior. We explain these aspects, and discuss some problems left open.
GLOBAL REGULARITY FOR A LOGARITHMICALLY SUPERCRITICAL DEFOCUSING NONLINEAR WAVE EQUATION FOR SPHERICALLY SYMMETRIC DATA
Authors: TAO TERENCE
Published: May 2007

We establish global regularity for the logarithmically energy-supercritical wave equation □u = u5 log (2 + u2) in three spatial dimensions for spherically symmetric initial data, by modifying an argument of Ginibre, Soffer and Velo for the energy-critical equation. This example demonstrates that critical regularity arguments can penetrate very slightly into the supercritical regime.
A MATHEMATICAL THEORY OF ISOLATED SYSTEMS IN RELATIVISTIC PLASMA PHYSICS
Authors: CALOGERO SIMONE
Published: May 2007

The existence and the properties of isolated solutions to the relativistic Vlasov–Maxwell system with initial data on the backward hyperboloid [Formula: see text] are investigated. Isolated solutions of Vlasov–Maxwell can be defined by the condition that the particle density is compactly supported on the initial hyperboloid and by imposing the absence of incoming radiation on the electromagnetic field. Various consequences of the mass-energy conservation laws are derived by assuming the existence of smooth isolated solutions which match the inital data. In particular, it is shown that the mass-energy of isolated solutions on the backward hyperboloids and on the surfaces of constant proper time are preserved and equal, while the mass-energy on the forward hyperboloids is non-increasing and uniformly bounded by the mass-energy on the initial hyperboloid. Moreover the global existence and uniqueness of classical solutions in the future of the initial surface is established for the one-dimensional version of the system.
GLOBAL SOLUTION FOR ROTATING COMPRESSIBLE PLASMA FLOW WITH LARGE DATA
Authors: WANG DEHUA , WANG ZEJUN
Published: May 2007

The initial boundary value problem for the Euler–Poisson equations of the two-dimensional compressible rotating plasma flow with large data in L∞is studied in the isothermal case. The shock capturing method is used to construct the approximate solution. The uniform estimate and the H-1estimate of the entropy dissipation measures are obtained, and the compensated compactness method is applied to show the convergence of the approximate solution. The nonlocal effect of the Poisson equation is analyzed. The limit of the approximate solution is a weak entropy solution. Therefore the global weak entropy solution in L∞to the Euler–Poisson equations for rotating plasma flow is constructed and the global existence is established.
Expression of c-Kit receptor tyrosine kinase and effect on β-cell development in the human fetal pancreas
Authors: Li Jinming , Quirt Jaclyn , Do Hung Quoc , Lyte Kristina , Fellows Fraser , Goodyer Cynthia G. , Wang Rennian
Published: May 2007

The receptor, c-Kit, and its ligand, stem cell factor (SCF), are critical for hematopoietic stem cell differentiation and have been implicated in the development, function, and survival of rodent islets. Previously, we reported that exogenous SCF treatments of cultured human fetal (14–16 wk fetal age) islet-epithelial clusters enhanced islet cell differentiation and proliferation (Li J, Goodyer CG, Fellows F, Wang R. Int J Biochem Cell Biol 38: 961–972, 2006). In the present study, we examined the expression pattern of c-Kit in early to midgestation human fetal pancreata and the relevance of c-Kit receptor tyrosine kinase for insulin gene expression and β-cell survival. c-Kit is expressed in the intact pancreas in a cell-specific manner, with a significant decrease in immunoreactivity in the duct regions from 8 to 21 wk fetal age, paralleled by a significant increase in expression within endocrine regions. These c-Kit-positive cells are highly proliferative and show frequent coexpression with insulin and glucagon. Treatment of islet-epithelial clusters with anti-ACK45 antibody stimulates c-Kit phosphorylation paralleled by a significant increase in PDX-1 and insulin expression, increased cell proliferation, and reduced β-cell death. In contrast, transient transfection with c-Kit siRNA results in a three- to fourfold decrease in c-Kit, PDX-1, and insulin expression and decreased cell proliferation. This study describes important changes in the distribution and dynamics of c-Kit-expressing cells during human fetal pancreatic neogenesis, suggesting that c-Kit may be a marker for human pancreatic islet progenitor cells. Functional analysis of the c-Kit receptor tyrosine kinase provides evidence that phosphorylation of c-Kit receptor may be involved in mediating early β-cell differentiation and survival.
Acute hyperglycemia exacerbates myocardial ischemia/reperfusion injury and blunts cardioprotective effect of GIK
Authors: Su Hui , Sun Xin , Ma Heng , Zhang Hai-Feng , Yu Qiu-Jun , Huang Chen , Wang Xiao-Ming , Luan Rong-Hua , Jia Guo-Liang , Wang Hai-Chang , Gao Feng
Published: May 2007

There is a close association between hyperglycemia and increased risk of mortality after acute myocardial infarction (AMI). However, whether acute hyperglycemia exacerbates myocardial ischemia/reperfusion (MI/R) injury remains unclear. We observed the effects of acute hyperglycemia on MI/R injury and on the cardioprotective effect of glucose-insulin-potassium (GIK). Male rats were subjected to 30 min of myocardial ischemia and 6 h of reperfusion. Rats were randomly received one of the following treatments (at 4 ml·kg−1·h−1 iv): Vehicle, GIK (GIK during reperfusion; glucose: 200g/l, insulin: 60 U/l, KCL: 60 mmol/l), HG (high glucose during ischemia; glucose:500 g/l), GIK + HG (HG during I and GIK during R) or GIK + wortmannin (GIK during R and wortmannin 15 min before R). Blood glucose, plasma insulin concentration and left ventricular pressure (LVP) were monitored throughout the experiments. Hyperglycemia during ischemia not only significantly increased myocardial apoptosis (23.6 ± 1.7% vs. 18.8 ± 1.4%, P < 0.05 vs. vehicle), increased infarct size (IS) (45.6 ± 3.0% vs. 37.6 ± 2.0%, P < 0.05 vs. vehicle), decreased Akt and GSK-3β phosphorylations (0.5 ± 0.2 and 0.6 ± 0.1% fold of vehicle, respectively, P < 0.05 vs. vehicle) following MI/R, but almost completely blocked the cardioprotective effect afforded by GIK, as evidenced by significantly increased apoptotic index (19.1 ± 2.0 vs. 10.3 ± 1.2%, P < 0.01 vs. GIK), increased myocardial IS (39.2 ± 2.8 vs. 27.2 ± 2.1%, P < 0.01 vs. GIK), decreased Akt phosphorylation (1.1 ± 0.1 vs. 1.7 ± 0.2%, P < 0.01 vs. GIK) and GSK-3β phosphorylation (1.4 ± 0.2 vs. 2.3 ± 0.2%, P < 0.05 vs. GIK). Hyperglycemia significantly exacerbates MI/R injury and blocks the cardioprotective effect afforded by GIK, which is, at least in part, due to hyperglycemia-induced decrease of myocardial Akt activation.
Calculating glucose fluxes during meal tolerance test: a new computational approach
Authors: Hovorka Roman , Jayatillake Harsha , Rogatsky Eduard , Tomuta Vlad , Hovorka Tomas , Stein Daniel T.
Published: May 2007

A new calculation method is proposed to quantify the endogenous glucose production (EGP), the glucose appearance rate due to meal ingestion (Ra meal), and the glucose disposal (Rd) during a three-tracer study design. The method utilizes the maximum likelihood theory combined with a regularization method to achieve a theoretically coherent computational framework. The method uses the two-compartment formulation of the glucose kinetics. Instead of assuming smoothness of unlabeled and labeled glucose concentrations, the method assumes that the EGP, the Ra meal, and the fractional glucose clearance are smooth, increasing plausibility of their individual estimates. The method avoids transformation of the measurement errors, which may skew the estimates of the EGP, Ra meal, and Rd with the traditional approach. Finally, the sequential nature of the calculations is replaced by calculating the EGP, Ra meal, and Rd in “one go” to avoid the propagation of the errors from the EGP and Ra meal into Rd. An example study is shown demonstrating the utility of the approach. A better performance of the new method is demonstrated in a simulation study.
A Biocompatible Titanium Headpost for Stabilizing Behaving Monkeys
Authors: Adams Daniel L. , Economides John R. , Jocson Cristina M. , Horton Jonathan C.
Published: May 2007

Many neurophysiological experiments involving monkeys require that the head be stabilized while the animal performs a task. Often a post is attached to the skull to accomplish this goal, using a headcap formed from dental acrylic. We describe a new headpost, developed by refinement of several prototypes, and supply an AutoCAD file to aid in machine shop production. This headpost is fabricated from a single piece of commercially pure titanium. It has a footplate consisting of four limbs arranged in the configuration of a “K.” These are bent during surgery to match the curvature of the skull and attached with specialized titanium bone screws. Headposts were implanted in seven rhesus monkeys ranging in age from 2 yr to adult. None has been rejected after up to 17 mo of regular use. They require little or no daily toilette and create only a 0.80-cm2 defect in the scalp. Computed tomography after implantation showed that the skull undergoes remodeling to embed the footplate in bone. This finding was confirmed by necropsy in two subjects. The outer table of the skull had grown over the titanium footplate, whereas the inner table had thickened to bury the tips of the titanium screws. The remarkable strength of the skull/implant bond was demonstrated by applying increasing amounts of torque to the headpost. At 26.3 Nm, the headpost tore from its metal footplate, but no screws came loose. The excellent performance of this implant is explained by integration of biocompatible titanium into remodeled bone tissue. The headpost is simpler to implant, more securely anchored, easier to maintain, and less obtrusive than devices attached with acrylic.
Spinal and Supraspinal Effects of Long-Term Stimulation of Sensorimotor Cortex in Rats
Authors: Chen Xiang Yang , Pillai Shreejith , Chen Yi , Wang Yu , Chen Lu , Carp Jonathan S. , Wolpaw Jonathan R.
Published: May 2007

Sensorimotor cortex (SMC) modifies spinal cord reflex function throughout life and is essential for operant conditioning of the H-reflex. To further explore this long-term SMC influence over spinal cord function and its possible clinical uses, we assessed the effect of long-term SMC stimulation on the soleus H-reflex. In freely moving rats, the soleus H-reflex was measured 24 h/day for 12 wk. The soleus background EMG and M response associated with H-reflex elicitation were kept stable throughout. SMC stimulation was delivered in a 20-day-on/20-day-off/20-day-on protocol in which a train of biphasic 1-ms pulses at 25 Hz for 1 s was delivered every 10 s for the on-days. The SMC stimulus was automatically adjusted to maintain a constant descending volley. H-reflex size gradually increased during the 20 on-days, stayed high during the 20 off-days, and rose further during the next 20 on-days. In addition, the SMC stimulus needed to maintain a stable descending volley rose steadily over days. It fell during the 20 off-days and rose again when stimulation resumed. These results suggest that SMC stimulation, like H-reflex operant conditioning, induces activity-dependent plasticity in both the brain and the spinal cord and that the plasticity responsible for the H-reflex increase persists longer after the end of SMC stimulation than that underlying the change in the SMC response to stimulation.
Differential expression, distribution, and function of PPAR-γ in the proximal and distal colon
Authors: Su Weidong , Bush Craig R. , Necela Brian M. , Calcagno Shelly R. , Murray Nicole R. , Fields Alan P. , Thompson E. Aubrey
Published: May 2007

Suppression of colon carcinogenesis by peroxisome proliferator-activated receptor (PPAR)-γ is likely due to some effect of PPAR-γ on normal colonic epithelial cells. However, our understanding of the effects of PPAR-γ in such cells is limited. We analyzed the abundance, distribution, and function of PPAR-γ in epithelial cells isolated from the murine proximal and distal colon. Marked differences in PPAR-γ abundance and distribution were observed, suggesting tissue-specific responses. Analysis of PPAR-γ effects on DNA synthesis, formation of preneoplastic lesions, and activation of MAPK signaling in proximal and distal colonic epithelial cells in vivo indicates that PPAR-γ regulates both tissue-specific and common responses within the proximal and distal colon. Three major functional cohorts of PPAR-γ target genes were identified by genomic profiling of isolated colonic epithelial cells: genes that are involved in metabolism, in signaling, and in cellular adhesion and motility. Two subsets of PPAR-γ target genes were differentially expressed in the proximal and distal epithelium. Proximal target genes were primarily involved in metabolic activities, whereas signal transduction, adhesion, and motility targets were more pronounced in the distal colon. Remarkably, those target genes that are differentially expressed in the proximal colon were all induced on activation of PPAR-γ, whereas all target genes that are preferentially expressed in the distal colon were repressed. Our data indicate that PPAR-γ exerts both common and tissue-specific effects in the colon and challenge the general conclusions that PPAR-γ is induced on differentiation of colonic epithelial cells and that this receptor stimulates differentiated function in epithelial cells throughout the colon.
Dead or alive: gene expression profiles of advanced atherosclerotic plaques from autopsy and surgery
Authors: Sluimer Judith C. , Kisters Natasja , Cleutjens Kitty B. , Volger Oscar L. , Horrevoets Anton J. , van den Akker Luc H. , Bijnens Ann-Pascale J. , Daemen Mat J.
Published: May 2007

Since inclusion of atherosclerotic tissues from different sources is often indispensable to study the full atherogenic spectrum, we investigated to what extent the expression profiles of advanced, stable atherosclerotic lesions obtained during autopsy and surgery are comparable. The gene expression profiles of human carotids with advanced atherosclerosis obtained at autopsy and at vascular surgery were studied by microarray analysis. Expression analysis was performed both at the single gene (Rosetta, Gene Ontology) and at the pathway level using Ingenuity and Gene Set Enrichment Analysis. In addition, mRNA and protein expression levels were validated using quantitative (q) RT-PCR and immunohistochemistry on unrelated advanced carotid lesions from autopsy and surgery. Microarray analysis indicated that the 97.2% of genes showed similar expression levels in advanced atherosclerotic lesions from autopsy and surgery. While the expression data revealed no differences in common atherosclerotic related pathways such as lipid metabolism and inflammation, the differentially expressed genes were mainly involved in basal cell metabolism and hypoxia driven pathways. qRT-PCR confirmed the differential expression of hypoxia-driven genes VEGF-A (2.3-fold ↑), glucose transporter (GLUT)-1 (2.5-fold ↑), GLUT3 (8.3-fold ↑), and hexokinase 1 (2.4-fold ↑) in autopsy vs. surgical specimens. Immunohistochemistry revealed that the transcriptional differences in these hypoxia-related genes were not reflected at the protein level. The gene expression profiles of advanced atherosclerotic lesions from autopsy and surgery are largely similar. However, >500 genes, mostly involved in basal cell metabolism and hypoxia were differentially expressed at mRNA, but not at the protein level.
Gene expression responses over 24 h to lengthening and shortening contractions in human muscle: major changes in CSRP3, MUSTN1, SIX1, and FBXO32
Authors: Kostek Matthew C. , Chen Yi-Wen , Cuthbertson Daniel J. , Shi Rongye , Fedele Mark J. , Esser Karyn A. , Rennie Michael J.
Published: May 2007

Resistance training using lengthening (eccentric) contractions induces greater increases in muscle size than shortening (concentric) contractions, but the underlying molecular mechanisms are not clear. Using temporal expression profiling, we compared changes in gene expression within 24 h of an acute bout of each type of contractions conducted simultaneously in the quadriceps of different legs. Five healthy young men performed shortening contractions with one leg while the contralateral leg performed lengthening contractions. Biopsies were taken from both legs before exercise and 3, 6, and 24 h afterwards, in the fed state. Expression profiling ( n = 3) was performed using a custom-made Affymetrix MuscleChip containing probe sets of ∼3,300 known genes and expressed sequence tags expressed in skeletal muscle. We identified 51 transcripts differentially regulated between the two exercise modes. Using unsupervised hierarchical clustering, we identified four distinct clusters, three of which corresponded to unique functional categories (protein synthesis, stress response/early growth, and sarcolemmal structure). Using quantitative RT-PCR ( n = 5), we verified expression changes (lengthening/shortening) in SIX1 (3 h, −1.9-fold, P < 0.001), CSRP3 (6 h, 2.9-fold, P < 0.05), and MUSTN1 (24 h, 4.3-fold, P < 0.05). We examined whether FBXO32/atrogin-1/MAFbx, a known regulator of protein breakdown and of muscle atrophy was differentially expressed: the gene was downregulated after lengthening contractions (3 h, 2.7-fold, P < 0.05; 6 h, 3.3-fold, P < 0.05; 24 h, 2.3-fold, P < 0.05). The results suggested that lengthening and shortening contractions activated distinct molecular pathways as early as 3 h postexercise. The molecular differences might contribute to mechanisms underlying the physiological adaptations seen with training using the two modes of exercise.
Genetic Basis for Congenital Heart Defects: Current Knowledge
Authors: Pierpont Mary Ella , Basson Craig T. , Benson D. Woodrow , Gelb Bruce D. , Giglia Therese M. , Goldmuntz Elizabeth , McGee Glenn , Sable Craig A. , Srivastava Deepak , Webb Catherine L.
Published: May 2007

The intent of this review is to provide the clinician with a summary of what is currently known about the contribution of genetics to the origin of congenital heart disease. Techniques are discussed to evaluate children with heart disease for genetic alterations. Many of these techniques are now available on a clinical basis. Information on the genetic and clinical evaluation of children with cardiac disease is presented, and several tables have been constructed to aid the clinician in the assessment of children with different types of heart disease. Genetic algorithms for cardiac defects have been constructed and are available in an appendix. It is anticipated that this summary will update a wide range of medical personnel, including pediatric cardiologists and pediatricians, adult cardiologists, internists, obstetricians, nurses, and thoracic surgeons, about the genetic aspects of congenital heart disease and will encourage an interdisciplinary approach to the child and adult with congenital heart disease.
Noninherited Risk Factors and Congenital Cardiovascular Defects: Current Knowledge
Authors: Jenkins Kathy J. , Correa Adolfo , Feinstein Jeffrey A. , Botto Lorenzo , Britt Amy E. , Daniels Stephen R. , Elixson Marsha , Warnes Carole A. , Webb Catherine L.
Published: May 2007

Prevention of congenital cardiovascular defects has been hampered by a lack of information about modifiable risk factors for abnormalities in cardiac development. Over the past decade, there have been major breakthroughs in the understanding of inherited causes of congenital heart disease, including the identification of specific genetic abnormalities for some types of malformations. Although relatively less information has been available on noninherited modifiable factors that may have an adverse effect on the fetal heart, there is a growing body of epidemiological literature on this topic. This statement summarizes the currently available literature on potential fetal exposures that might alter risk for cardiovascular defects. Information is summarized for periconceptional multivitamin or folic acid intake, which may reduce the risk of cardiac disease in the fetus, and for additional types of potential exposures that may increase the risk, including maternal illnesses, maternal therapeutic and nontherapeutic drug exposures, environmental exposures, and paternal exposures. Information is highlighted regarding definitive risk factors such as maternal rubella; phenylketonuria; pregestational diabetes; exposure to thalidomide, vitamin A cogeners, or retinoids; and indomethacin tocolysis. Caveats regarding interpretation of possible exposure-outcome relationships from case-control studies are given because this type of study has provided most of the available information. Guidelines for prospective parents that could reduce the likelihood that their child will have a major cardiac malformation are given. Issues related to pregnancy monitoring are discussed. Knowledge gaps and future sources of new information on risk factors are described.
Daily Microwave-Derived Surface Temperature over Canada/Alaska
Authors: Mialon A. , Royer A. , Fily M. , Picard G.
Published: May 2007

The land surface temperature variation over northern high latitudes in response to the increase in greenhouse gases is challenging because of the lack of meteorological stations. A new method to derive the surface temperature from satellite microwave measurements that improves the frequency of measurements relative to that of infrared data is presented. The daily Special Sensor Microwave Imager 25 km × 25 km Equal-Area Scalable Earth Grid (EASE-Grid) dataset provided by the National Snow and Ice Data Center in Boulder, Colorado, is processed to derive the surface temperature using the method proposed by Fily et al. A normalization approach based on the 40-yr ECMWF reanalysis (ERA-40; 2.5°) temperature diurnal cycle fitted for each pixel is applied to overcome the time acquisition variation of measurements as well as to interpolate missing data. An adaptive mask for discriminating between ice-free pixels and snow-free pixels is also applied. The resulting database is thus a new consistent hourly series of near-surface air temperatures during the summer (without snow). The mean accuracy is on the order of 2.5–3 K when compared with the synchronous in situ air temperature and different gridded datasets over Canada and Alaska. The trend over the last 10 yr confirms observed climate evolution: an increase in summer surface temperature of +0.09° ± 0.04°C yr−1, at the 90% confidence level, for Canada between 1992 and 2002, whereas a decrease of −0.15° ± 0.05°C yr−1, at the 95% confidence level, is observed for Alaska. Spatial and temporal anomalies show regional impacts of meteorological phenomena such as the El Niño extreme warm summer episode of 1998, the decrease in temperatures in 1992 in Canada following the volcanic eruption of Mount Pinatubo in June 1991, and the strong drought in the prairies in 2001. The annual sum of positive degree-days (thawing index) has been related to the permafrost distribution. The lower values of the derived thawing index (<1400 degree-days) are related well to the presence of continuous and dense discontinuous permafrost. The observed increase in the thawing index during the 1992–2002 period represents a decrease of classified permafrost area of 7%.
A Satellite-Based Parameter to Monitor the Aerosol Impact on Convective Clouds
Authors: Lensky Itamar M. , Drori Ron
Published: May 2007

A method to monitor the aerosol impact on convective clouds using satellite data is presented. The impacts of forest fires and highly polluting megacities on cloud precipitation formation processes are quantified by the vertical extent above cloud base to which convective cloud tops have to develop for onset of precipitation in terms of temperature difference D15. Large D15 is a manifestation of the precipitation suppression effect of small cloud condensation nuclei aerosols that elevate the altitude where effective precipitation processes are initiated. A warmer land surface with a greater sensible heat flux that increases the updraft velocity at cloud base may also contribute to the same effect. Therefore, D15 is greater for clouds that develop over more polluted and/or warmer surfaces that result from smoke and urban pollution and/or urban heat island, respectively. The precipitation suppression effects of both smoke from forest fires and urban effects can be vividly seen in a case study over Southeast Asia. Typical values of D15 are 1°–6°C for tropical maritime clouds, 8°–15°C for tropical clouds over land, 16°–26°C for urban air pollution, and 18°–39°C for clouds ingesting smoke from forest fires.
Evaluation of Ice Water Content Retrievals from Cloud Radar Reflectivity and Temperature Using a Large Airborne In Situ Microphysical Database
Authors: Protat A. , Delanoë J. , Bouniol D. , Heymsfield A. J. , Bansemer A. , Brown P.
Published: May 2007

The objective of this paper is to assess the performances of the proposed ice water content (IWC)–radar reflectivity Z and IWC–Z–temperature T relationships for accurate retrievals of IWC from radar in space or at ground-based sites, in the framework of the forthcoming CloudSat spaceborne radar, and of the European CloudNET and U.S. Atmospheric Radiation Measurement Program projects. For this purpose, a large airborne in situ microphysical database is used to perform a detailed error analysis of the IWC–Z and IWC–Z–T methods. This error analysis does not include the error resulting from the mass–dimension relationship assumed in these methods, although the expected magnitude of this error is bounded in the paper. First, this study reveals that the use of a single IWC–Z relationship to estimate IWC at global scale would be feasible up to −15 dBZ, but for larger reflectivities (and therefore larger IWCs) different sets of relationships would have to be used for midlatitude and tropical ice clouds. New IWC–Z and IWC–Z–T relationships are then developed from the large aircraft database and by splitting this database into midlatitude and tropical subsets, and an error analysis is performed. For the IWC–Z relationships, errors decrease roughly linearly from +210%/−70% for IWC = 10−4 g m−3 to +75%/−45% for IWC = 10−2 g m−3, are nearly constant (+50%/−33%) for the intermediate IWCs (0.03–1 g m−3), and then linearly increase up to +210%/−70% for the largest IWCs. The error curves have the same shape for the IWC–Z–T relationships, with a general reduction of errors with respect to the IWC–Z relationships. Comparisons with radar–lidar retrievals confirm these findings. The main improvement brought by the use of temperature as an additional constraint to the IWC retrieval is to reduce both the systematic overestimation and rms differences of the small IWCs (IWC < 0.01 g m−3). For the large IWCs, the use of temperature also results in a slight reduction of the rms differences but in a substantial reduction (by a factor of 2) of the systematic underestimation of the large IWCs, probably owing to a better account of the Mie effect when IWC–Z relationships are stratified by temperature.
A Statistical and Physical Description of Hydrometeor Distributions in Colorado Snowstorms Using a Video Disdrometer
Authors: Brandes Edward A. , Ikeda Kyoko , Zhang Guifu , Schönhuber Michael , Rasmussen Roy M.
Published: May 2007

Winter-storm hydrometeor distributions along the Front Range in eastern Colorado are studied with a ground-based two-dimensional video disdrometer. The instrument provides shape, size, and terminal velocity information for particles that are larger than about 0.4 mm. The dataset is used to determine the form of particle size distributions (PSDs) and to search for useful interrelationships among the governing parameters of assumed distribution forms and environmental factors. Snowfalls are dominated by almost spherical aggregates having near-exponential or superexponential size distributions. Raindrop size distributions are more peaked than those for snow. A relation between bulk snow density and particle median volume diameter is derived. The data suggest that some adjustment may be needed in relationships found previously between temperature and the concentration and slope parameters of assumed exponential PSDs. A potentially useful relationship is found between the slope and shape terms of the gamma PSD model.