bluuebunny/crossref_metadata_2025 huggingface dataset:
UO2 (111) Single Crystal: Comparison of Stoichiometric and Defective Surfaces by XPS
Authors: Senanayake Sanjaya D. , Idriss Hicham
Published: December 2007

This work undertakes a photoelectron study of the surface of a uranium dioxide(111) single crystal. The formation of a defected surface with argon ions sputtering can be identified as an n-type semiconductor, UO2-x phase. Annealing to high temperatures under an oxygen pressure of ∼5 × 10−6 Torr for 30 min or more yielded the hyper-stoichiometric p-type semiconductor, UO2+x phase. A shift in the core level line of U4+ ions is observed and attributed to a shift in the Fermi level from hyper-stoichiometric UO2+x to sub-stoichiometric UO2-x.
Cr2O3 Thin Films on Ag(111) by XPS
Authors: Priyantha W.A.A. , Waddill George D.
Published: December 2007

Cr2O3 (0001) films are grown on Ag(111) by repeated cycles of 0.5 ML deposition of Cr followed by annealing in O2 at 240 °C for 5 min at 10-5 Torr. The spectra shown are for a 15 Å thick Cr2O3 film.
ZnO:Er(III) Nanosystems Analyzed by XPS
Authors: Armelao Lidia , Barreca Davide , Bottaro Gregorio , Gasparotto Alberto , Leonarduzzi Daniele , Maragno Cinzia , Tondello Eugenio
Published: December 2007

ZnO:Er(III) nanosystems were synthesized by a combined rf-sputtering/sol-gel (SG) approach. In particular, the adopted route consists in the rf-sputtering of erbium (guest) onto as-prepared zinc oxide xerogels (host) obtained via sol-gel, followed by ex-situ heat treatments in air (300-600 °C, 1-5 h). The obtained samples were analyzed by glancing incidence x-ray diffraction (GIXRD), atomic force microscopy (AFM), secondary ion mass spectrometry (SIMS) and x-ray photoelectron spectroscopy (XPS), for a detailed investigation of their microstructure, surface morphology and chemical composition. The present work focuses on the XPS analysis of a selected ZnO:Er specimen, annealed at 400 °C for 5 h. Besides the wide scan spectrum, detailed spectra for the Zn 2p3/2, Zn 3p, Er 4d, O ls and C 1s regions and related data are presented and discussed.
XPS Study of MgO Nanopowders Obtained by Different Preparation Procedures
Authors: Khairallah Fares , Glisenti Antonella
Published: December 2007

Three different samples of nanoscale magnesium oxide were synthesized using an “aqueous wet chemical method” and a “surfactant method”. In the first case, MgO was obtained by gelation/precipitation from a solution containing Mg2+ while in the surfactant method a micellar liquid is created by adding the Mg2+ solution to the surfactant. In this last case two different surfactants have been used: Brij 56 and Triton 100-x. In this work, the influence of the preparation procedure on the surface properties is investigated by XPS. Besides the wide scan spectrum, detailed spectra for the Mg 1s, Mg 2p, O 1s and C is regions and related data are presented and discussed. The XPS analysis shows the presence of magnesium carbonate in the outermost layers. Carbonate species are more evident in the samples obtained by the surfactant method whereas no significant differences can be observed by using different surfactants. Moreover, in all the nanopowders, both MgO and Mg(OH)2 are evident.
Core Level XPS Spectra of Silicon Dioxide Using Zirconium and Magnesium Radiations
Authors: Chourasia A. R.
Published: December 2007

Core levels of silicon and oxygen in silicon dioxide have been studied by x-ray photoelectron spectroscopy. For this purpose zirconium Lalpha (energy = 2042.4 eV) and magnesium Kalpha (energy = 1253.6 eV) radiations have been employed. The XPS data in the silicon 1s, 2s, 2p, and Auger KLL, and oxygen 1s, and Auger KLL regions are presented. The spectral data have not been corrected for the charging effect. The data set will serve as a source of valuable information for analyzing spectra associated with silicon and oxygen in silicon dioxide.
Cleaved Natural Orpiment (As2S3) by XPS
Authors: Corkhill Claire , Wincott Paul L. , Vaughan David J.
Published: December 2007

Orpiment (As2S3) is an arsenic ore mineral formed in low temperature hydrothermal veins and hotsprings, and commonly associated with other arsenic minerals such as realgar (AsS). It is of significance environmentally in areas affected by acid mine drainage where oxidation causes both the generation of acid and the release of arsenic in surface water and groundwater. The sample studied here is a natural crystal from Twin Creeks Mine, Nevada, which was fractured along the [010] cleavage plane under a dry nitrogen atmosphere before XPS analysis. General survey and high resolution spectra were collected using a Kratos Axis Ultra spectrometer under normal operating conditions. Adventitious carbon was used for energy referencing. Charge corrected binding energies for the photoelectrons emitted from orpiment (S 2s, S 2p, As 3p, As 3d, O 1s and C 1s) are reported. These binding energies are of use in experiments characterising the surface chemistry of orpiment providing insights into the reactivity of the mineral.
Cleaved Natural Realgar (AsS) by XPS
Authors: Corkhill Claire , Wincott Paul L. , Vaughan David J.
Published: December 2007

Realgar (AsS) is an arsenic ore mineral formed in low temperature hydrothermal veins and hotsprings, and commonly associated with other arsenic minerals such as orpiment (As2S3). It is of significance environmentally in areas affected by acid mine drainage where oxidation causes both the generation of acid and the release of arsenic in surface water and groundwater. The sample studied here is a natural crystal from The Realgar Mine, Shimen, China, which was fractured along the [010] cleavage plane under a dry nitrogen atmosphere before XPS analysis. General survey and high resolution spectra were collected using a Kratos Axis Ultra spectrometer under normal operating conditions. Adventitious carbon was used for energy referencing. Charge corrected binding energies for the photoelectrons emitted from realgar (S 2s, S 2p, As 3p, As 3d, O 1s and C 1s) are reported. These binding energies are of use in experiments characterising the surface chemistry of realgar providing insights into the reactivity of the mineral.
Cerium (III) Fluoride Thin Films by XPS
Authors: Barreca Davide , Gasparotto Alberto , Maccato Chiara , Maragno Cinzia , Tondello Eugenio
Published: December 2007

Nanocrystalline cerium fluoride thin films were synthesized by chemical vapor deposition (CVD) using Ce(hfa)3·diglyme (hfa=1,1,1,5,5,5-hexafluoro-2,4-pentanedionate; diglyme=bis (2-metoxyethyl)ether) as precursor compound on Si(100) under N2+O2 atmosphere. The obtained samples were analyzed by glancing-incidence x-ray diffraction (GIXRD), x-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), for a thorough characterization of their microstructure, chemical composition, and morphology. This work is specifically dedicated to the XPS characterization of a representative CeF3 thin film deposited at 350 °C. Besides the wide scan spectrum, detailed spectra for the Ce 3d, F 1s, O 1s, and C 1s regions and related data are presented and discussed. Both the F/Ce atomic ratio and Ce 3d peak shape and position point out to the formation of CeF3 films, in agreement with the structural characterization. Moreover, carbon contamination is merely limited to the outermost sample layers.
THE AUSLANDER–REITEN SEQUENCES ENDING AT GABRIEL–ROITER FACTOR MODULES OVER TAME HEREDITARY ALGEBRAS
Authors: CHEN BO
Published: December 2007

Let Λ = kQ be a finite dimensional hereditary algebra over an algebraically closed field k with Q a quiver of Euclidean type [Formula: see text], [Formula: see text], or [Formula: see text]. We study the Auslander–Reiten sequences terminating at Gabriel–Roiter factor modules and show that for almost all but finitely many Gabriel–Roiter factor modules, the Auslander–Reiten sequences have indecomposable middle terms.
GROUPS OF EVEN REAL GENUS
Authors: MAY COY L.
Published: December 2007

Let G be a finite group. The real genusρ (G) is the minimum algebraic genus of any compact bordered Klein surface on which G acts. Here we develop some constructions of groups of even real genus, first using the notion of a semidirect product. As a consequence, we are able to show that for each integer g in certain congruence classes, there is at least one group of genus g. Next we consider the direct product Zn × G, in which one factor is cyclic and the other is a group of odd order that is generated by two elements. By placing a restriction on the genus action of G, we find the real genus of the direct product, in case n is relatively prime to |G|. We give some applications of this result, in particular to O*-groups, the odd order groups of maximum possible order. Finally we apply our results to the problem of determining whether there is a group of real genus g for each value of g. We prove that the set of integers for which there is a group has lower density greater than 5/6.
PURE SEMISIMPLE FINITELY ACCESSIBLE CATEGORIES AND HERZOG'S CRITERION
Authors: CÁRCELES A. I. , GARCÍA J. L.
Published: December 2007

Let [Formula: see text] be a finitely accessible category with products, and assume that its symmetric category [Formula: see text] is also finitely accessible and pure semisimple. We study necessary and sufficient conditions in both categories for [Formula: see text] (and hence [Formula: see text]) to be of locally finite representation type. In particular, we obtain a generalization of Herzog's criterion for finite representation type of left pure semisimple and right artinian rings. As an application, we prove that a left pure semisimple ring R with enough idempotents which has a self-duality is of locally finite representation type if and only if it is left locally finite.
FACTORIZATION OF QUADRATIC POLYNOMIALS IN THE RING OF FORMAL POWER SERIES OVER ℤ
Authors: BIRMAJER DANIEL , GIL JUAN B. , WEINER MICHAEL D.
Published: December 2007

We establish necessary and sufficient conditions for a quadratic polynomial to be irreducible in the ring ℤ[[x]] of formal power series over the integers. In particular, for polynomials of the form pn + pm βx + αx2 with n,m ≥ 1 and p prime, we show that reducibility in ℤ[[x]] is equivalent to reducibility in ℤp[x], the ring of polynomials over the p-adic integers.
STAR PRODUCTS ON GENERALIZED COMPLEX MANIFOLDS
Authors: ISIDRO JOSÉ M.
Published: December 2007

We regard classical phase space as a generalized complex manifold and analyze the B-transformation properties of the ⋆-product of functions. The C⋆-algebra of smooth functions transforms in the expected way, while the C⋆-algebra of holomorphic functions (when it exists) transforms nontrivially. The B-transformed ⋆-product encodes all the properties of phase-space quantum mechanics in the presence of a background magnetic field.
PARAMETRIC NONHOLONOMIC FRAME TRANSFORMS AND EXACT SOLUTIONS IN GRAVITY
Authors: VACARU SERGIU I.
Published: December 2007

A generalized geometric method is developed for constructing exact solutions of gravitational field equations in Einstein theory and generalizations. First, we apply the formalism of nonholonomic frame deformations (formally considered for nonholonomic manifolds and Finsler spaces) when the gravitational field equations transform into systems of nonlinear partial differential equations which can be integrated in general form. The new classes of solutions are defined by generic off-diagonal metrics depending on integration functions on one, two and three (or three and four) variables if we consider four (or five) dimensional spacetimes. Second, we use a general scheme when one (two) parameter families of exact solutions are defined by any source-free solutions of Einstein's equations with one (two) Killing vector field(s). A successive iteration procedure results in new classes of solutions characterized by an infinite number of parameters for a non-Abelian group involving arbitrary functions on one variable. Five classes of exact off-diagonal solutions are constructed in vacuum Einstein and in string gravity describing solitonic pp-wave interactions. We explore possible physical consequences of such solutions derived from primary Schwarzschild or pp-wave metrics.
GRADED INFINITE ORDER JET MANIFOLDS
Authors: SARDANASHVILY G.
Published: December 2007

The relevant material on differential calculus on graded infinite order jet manifolds and its cohomology is summarized. This mathematics provides the adequate formulation of Lagrangian theories of even and odd variables on smooth manifolds in terms of the Grassmann-graded variational bicomplex.
Corticosteroids increase glutamine utilization in human splanchnic bed
Authors: Thibault Ronan , Welch Susan , Mauras Nelly , Sager Brenda , Altomare Astride , Haymond Morey , Darmaun Dominique
Published: December 2007

Glutamine is the most abundant amino acid in the body and is extensively taken up in gut and liver in healthy humans. To determine whether glucocorticosteroids alter splanchnic glutamine metabolism, the effect of prednisone was assessed in healthy volunteers using isotope tracer methods. Two groups of healthy adults received 5-h intravenous infusions of l-[1-14C]leucine and l-[2H5]glutamine, along with q. 20 min oral sips of tracer doses of l-[1-13C]glutamine in the fasting state, either 1) at baseline (control group; n = 6) or 2) after a 6-day course of 0.8 mg·kg−1·day−1 prednisone (prednisone group; n = 8). Leucine and glutamine appearance rates (Ra) were determined from plasma [1-14C]ketoisocaproate and [2H5]glutamine, respectively, and leucine and glutamine oxidation from breath 14CO2 and 13CO2, respectively. Splanchnic glutamine extraction was estimated by the fraction of orally administered [13C]glutamine that failed to appear into systemic blood. Prednisone treatment 1) did not affect leucine Ra or leucine oxidation; 2) increased plasma glutamine Ra, mostly owing to enhanced glutamine de novo synthesis (medians ± interquartiles, 412 ± 61 vs. 280 ± 190 μmol·kg−1·h−1, P = 0.003); and 3) increased the fraction of orally administered glutamine undergoing extraction in the splanchnic territory (means ± SE 64 ± 6 vs. 42 ± 12%, P < 0.05), without any change in the fraction of glutamine oxidized (means ± SE, 75 ± 4 vs. 77 ± 4%, not significant). We conclude that high-dose glucocorticosteroids increase in splanchnic bed the glutamine requirements. The role of such changes in patients receiving chronic corticoid treatment for inflammatory diseases or suffering from severe illness remains to be determined.
Aldosterone acts centrally to increase brain renin-angiotensin system activity and oxidative stress in normal rats
Authors: Zhang Zhi-Hua , Yu Yang , Kang Yu-Ming , Wei Shun-Guang , Felder Robert B.
Published: December 2007

Aldosterone acts upon mineralocorticoid receptors in the brain to increase blood pressure and sympathetic nerve activity, but the mechanisms are still poorly understood. We hypothesized that aldosterone increases sympathetic nerve activity by upregulating the renin-angiotensin system (RAS) and oxidative stress in the brain, as it does in peripheral tissues. In Sprague-Dawley rats, aldosterone (Aldo) or vehicle (Veh) was infused for 1 wk via an intracerebroventricular (ICV) cannula, while RU-28318 (selective mineralocorticoid receptor antagonist), Tempol (superoxide dismutase mimetic), losartan [angiotensin II type 1 receptor (AT1R) antagonist], or Veh was infused simultaneously via a second ICV cannula. After 1 wk of ICV Aldo, plasma norepinephrine was increased and mean arterial pressure was slightly elevated, but heart rate was unchanged. These effects were ameliorated by ICV infusion of RU-28318, Tempol or losartan. Aldo increased expression of AT1R and angiotensin-converting enzyme (ACE) mRNA in hypothalamic tissue. RU-28318 minimized and Tempol prevented the increase in AT1R mRNA; RU-28318 prevented the increase in ACE mRNA. Losartan had no effect on AT1R or ACE mRNA. Immunohistochemistry revealed Aldo-induced increases in dihydroethidium staining (indicating oxidative stress) and Fra-like activity (indicating neuronal excitation) in neurons of the hypothalamic paraventricular nucleus (PVN). RU-28318 prevented the increases in superoxide and Fra-like activity in PVN; Tempol and losartan minimized these effects. Acute ICV infusions of sarthran (AT1R antagonist) or Tempol produced greater sympathoinhibition in Aldo-treated than in Veh-treated rats. Thus aldosterone upregulates key elements of brain RAS and induces oxidative stress in the hypothalamus. Aldosterone may increase sympathetic nerve activity by these mechanisms.
The effects of caloric restriction- and exercise-induced weight loss on left ventricular diastolic function
Authors: Riordan Matt M. , Weiss Edward P. , Meyer Timothy E. , Ehsani Ali A. , Racette Susan B. , Villareal Dennis T. , Fontana Luigi , Holloszy John O. , Kovács Sándor J.
Published: December 2007

Little is known about the effects of weight loss on diastolic function. Furthermore, it is not known whether both caloric restriction (CR)- and exercise (Ex)-induced weight loss have salutary effects on diastolic function. Therefore, we assessed the effects of yearlong CR ( n = 12) and Ex ( n = 13) interventions, which induced ∼12% weight loss, on diastolic function in healthy, nonobese (body mass index = 23.5–29.9 kg/m2) men and women aged 50 to 60 yr. Recordings of Doppler transmitral flow and Doppler tissue imaging were acquired and analyzed by conventional approaches and a validated parameterized diastolic filling (PDF) formalism. Isovolumic relaxation time decreased after weight loss in both groups ( P < 0.05). Septal peak early mitral annular velocity (E′) increased ( P < 0.01) and peak E-wave velocity/E′ decreased ( P < 0.05) after weight loss in the CR group. Based on the PDF-derived indexes, CR resulted in a decrease in global ventricular stiffness ( k) and increases in longitudinal (septal annulus motion) stored elastic strain ( x′o), peak force ( k′ x′o), and peak stored strain energy (1/2 k′ xoprime;2). In the Ex group, k was unchanged, although septal x′o and 1/2 k′ xo′2 increased significantly and k′ x′o ( P = 0.13) tended to increase. We conclude that weight loss, whether induced by CR or Ex, has salutary effects on diastolic function.
PPAR-γ agonists inhibit profibrotic phenotypes in human lung fibroblasts and bleomycin-induced pulmonary fibrosis
Authors: Milam Jami E. , Keshamouni Venkateshwar G. , Phan Sem H. , Hu Biao , Gangireddy Srinivasa R. , Hogaboam Cory M. , Standiford Theodore J. , Thannickal Victor J. , Reddy Raju C.
Published: December 2007

Pulmonary fibrosis is characterized by alterations in fibroblast phenotypes resulting in excessive extracellular matrix accumulation and anatomic remodeling. Current therapies for this condition are largely ineffective. Peroxisome proliferator-activated receptor-γ (PPAR-γ) is a member of the nuclear hormone receptor superfamily, the activation of which produces a number of biological effects, including alterations in metabolic and inflammatory responses. The role of PPAR-γ as a potential therapeutic target for fibrotic lung diseases remains undefined. In the present study, we show expression of PPAR-γ in fibroblasts obtained from normal human lungs and lungs of patients with idiopathic interstitial pneumonias. Treatment of lung fibroblasts and myofibroblasts with PPAR-γ agonists results in inhibition of proliferative responses and induces cell cycle arrest. In addition, PPAR-γ agonists, including a constitutively active PPAR-γ construct (VP16-PPAR-γ), inhibit the ability of transforming growth factor-β1 to induce myofibroblast differentiation and collagen secretion. PPAR-γ agonists also inhibit fibrosis in a murine model, even when administration is delayed until after the initial inflammation has largely resolved. These observations indicate that PPAR-γ is an important regulator of fibroblast/myofibroblast activation and suggest a role for PPAR-γ ligands as novel therapeutic agents for fibrotic lung diseases.
Measuring endothelial glycocalyx dimensions in humans: a potential novel tool to monitor vascular vulnerability
Authors: Nieuwdorp Max , Meuwese Marijn C. , Mooij Hans L. , Ince Can , Broekhuizen Lysette N. , Kastelein John J. P. , Stroes Erik S. G. , Vink Hans
Published: December 2007

The endothelial glycocalyx is increasingly considered as an intravascular compartment that protects the vessel wall against pathogenic insults. The purpose of this study was to translate an established experimental method of estimating capillary glycocalyx dimension into a clinically useful tool and to assess its reproducibility in humans. We first evaluated by intravital microscopy the relation between the distance between the endothelium and erythrocytes, as a measure of glycocalyx thickness, and the transient widening of the erythrocyte column on glycocalyx compression by passing leukocytes in hamster cremaster muscle capillaries. We subsequently assessed sublingual microvascular glycocalyx thickness in 24 healthy men using orthogonal polarization spectral imaging. In parallel, systemic glycocalyx volume (using a previously published tracer dilution technique) as well as cardiovascular risk profiles were assessed. Estimates of microvascular glycocalyx dimension from the transient erythrocyte widening correlated well with the size of the erythrocyte-endothelium gap ( r = 0.63). Measurements in humans were reproducible (0.58 ± 0.16 and 0.53 ± 0.15 μm, coefficient of variance 15 ± 5%). In univariate analysis, microvascular glycocalyx thickness significantly correlated with systemic glycocalyx volume ( r = 0.45), fasting plasma glucose ( r = 0.43), and high-density lipoprotein-cholesterol ( r = 0.40) and correlated negatively with low-density lipoprotein-cholesterol ( r = −0.41) as well as body mass index ( r = −0.45) (all P < 0.05). In conclusion, the dimension of the endothelial glycocalyx can be measured reproducibly in humans and is related to cardiovascular risk factors. It remains to be tested whether glycocalyx dimension can be used as an early marker of vascular damage and whether therapies aimed at glycocalyx repair can protect the vasculature against pathogenic challenges.
Respiration during feeding on solid food: alterations in breathing during mastication, pharyngeal bolus aggregation, and swallowing
Authors: Matsuo Koichiro , Hiiemae Karen M. , Gonzalez-Fernandez Marlis , Palmer Jeffrey B.
Published: December 2007

During feeding, solid food is chewed and propelled to the oropharynx, where the bolus gradually aggregates while the larynx remains open and breathing continues. The aggregated bolus in the valleculae is exposed to respiratory airflow, yet aspiration is rare in healthy individuals. The mechanism for preventing aspiration during bolus aggregation is unclear. One possibility is that alterations in the pattern of respiration during feeding could help prevent inhalation of food from the pharynx. We hypothesized that respiration was inhibited during bolus aggregation in the valleculae. Videofluorography was performed on 10 healthy volunteers eating solid foods with barium. Respiration was monitored concurrently with plethysmography and nasal air pressure. The timing of events during mastication, food transport, pharyngeal bolus aggregation, and swallowing were measured in relation to respiration. Respiratory cycle duration decreased during chewing ( P < 0.001) but increased with swallowing ( P < 0.001). During 66 recordings of vallecular bolus aggregation, there was inspiration in 8%, expiration in 41%, a pause in breathing in 17%, and multiple phases (including inspiration) in 35%. Out of 98 swallows, 47% started in the expiratory phase and 50% started during a pause in breathing, irrespective of bolus aggregation in the valleculae. Plethysmography was better than nasal manometry for determining the end of active expiration during feeding and swallowing with solid food. The hypothesis is rejected in that respiration was not inhibited during bolus aggregation. These findings suggest that airflow through the pharynx does not have a role in preventing aspiration during bolus aggregation in the oropharynx.
Maintenance of gasping and restoration of eupnea after hypoxia is impaired following blockers of α1-adrenergic receptors and serotonin 5-HT2 receptors
Authors: St.-John Walter M. , Leiter J. C.
Published: December 2007

In severe hypoxia or ischemia, normal eupneic breathing fails and is replaced by gasping. Gasping serves as part of a process of autoresuscitation by which eupnea is reestablished. Medullary neurons, having a burster, pacemaker discharge, underlie gasping. Conductance through persistent sodium channels is essential for the burster discharge. This conductance is modulated by norepinephrine, acting on α1-adrenergic receptors, and serotonin, acting on 5-HT2 receptors. We hypothesized that blockers of 5-HT2 receptors and α1-adrenergic receptors would alter autoresuscitation. The in situ perfused preparation of the juvenile rat was used. Integrated phrenic discharge was switched from an incrementing pattern, akin to eupnea, to the decrementing pattern comparable to gasping in hypoxic hypercapnia. With a restoration of hyperoxic normocapnia, rhythmic, incrementing phrenic discharge returned within 10 s in most preparations. Following addition of blockers of α1-adrenergic receptors (WB-4101, 0.0625–0.500 μM) and/or blockers of 5-HT2 (ketanserin, 1.25–10 μM) or multiple 5-HT receptors (methysergide, 3.0–10 μM) to the perfusate, incrementing phrenic discharge continued. Fictive gasping was still induced, although it ceased after significantly fewer decrementing bursts than in preparations than received no blockers. Moreover, the time for recovery of rhythmic activity was significantly prolonged. This prolongation was in excess of 100 s in all preparations that received both WB-4101 (above 0.125 μM) and methysergide (above 2.5 μM). We conclude that activation of adrenergic and 5-HT2 receptors is important to sustain gasping and to restore rhythmic respiratory activity after hypoxia-induced depression.
The cross-bridge cycle and skeletal muscle fatigue
Authors: Fitts Robert H.
Published: December 2007

The functional correlates of fatigue observed in both animals and humans during exercise include a decline in peak force (P0), maximal velocity, and peak power. Establishing the extent to which these deleterious functional changes result from direct effects on the myofilaments is facilitated through understanding the molecular mechanisms of the cross-bridge cycle. With actin-myosin binding, the cross-bridge transitions from a weakly bound low-force state to a strongly bound high-force state. Low pH reduces the number of high-force cross bridges in fast fibers, and the force per cross bridge in both fast and slow fibers. The former is thought to involve a direct inhibition of the forward rate constant for transition to the strong cross-bridge state. In contrast, inorganic phosphate (Pi) is thought to reduce P0 by accelerating the reversal of this step. Both H+ and Pi decrease myofibrillar Ca2+ sensitivity. This effect is particularly important as the amplitude of the Ca2+ transient falls with fatigue. The inhibitory effects of low pH and high Pi on P0 are reduced as temperature increases from 10 to 30°C. However, the H+-induced depression of peak power in the slow fiber type, and Pi inhibition of myofibrillar Ca2+ sensitivity in slow and fast fibers, are greater at high compared with low temperature. Thus the depressive effects of H+ and Pi at in vivo temperatures cannot easily be predicted from data collected below 25° C. In vitro, reactive oxygen species reduce myofibrillar Ca2+ sensitivity; however, the importance of this mechanism during in vivo exercise is unknown.
Biomarker discovery: proteome fractionation and separation in biological samples
Authors: Matt Peter , Fu Zongming , Fu Qin , Van Eyk Jennifer E.
Published: December 2007

Proteomics, analogous with genomics, is the analysis of the protein complement present in a cell, organ, or organism at any given time. While the genome provides information about the theoretical status of the cellular proteins, the proteome describes the actual content, which ultimately determines the phenotype. The broad application of proteomic technologies in basic science and clinical medicine has the potential to accelerate our understanding of the molecular mechanisms underlying disease and may facilitate the discovery of new drug targets and diagnostic disease markers. Proteomics is a rapidly developing and changing scientific discipline, and the last 5 yr have seen major advances in the underlying techniques as well as expansion into new applications. Core technologies for the separation of proteins and/or peptides are one- and two-dimensional gel electrophoresis and one- and two-dimensional liquid chromatography, and these are coupled almost exclusively with mass spectrometry. Proteomic studies have shown that the most effective analysis of even simple biological samples requires subfractionation and/or enrichment before protein identification by mass spectrometry. Selection of the appropriate technology or combination of technologies to match the biological questions is essential for maximum coverage of the selected subproteome and to ensure both the full interpretation and the downstream utility of the data. In this review, we describe the current technologies for proteome fractionation and separation of biological samples, based on our lab workflow for biomarker discovery and validation.
X-ray reflectivity and diffraction investigation on TiN/SiNx nanolayered coatings deposited by magnetron sputtering
Authors: An Tao , Tian Hongwei , Zheng Weitao
Published: December 2007

Polycrystalline
TiN/SiNx multilayer coatings were deposited by reactive magnetron sputtering from Ti and Si targets. Interfaces, structures, and mechanical properties of the multilayers were characterized using X-ray reflectivity (XRR), X-ray diffraction (XRD), and nanoindentation analyses. Results showed that substrate bias voltage had a significant influence on the structures and mechanical properties of the multilayer coatings, in which sharp interfaces are responsible for an enhancement of mechanical properties of the multilayer coatings. The maximum hardness occurs at the −80 V coating with the sharpest interface and the strongest [200] preferred orientation.
Neutron diffraction study on crystal structure and phase transformation in Ni-Mn-Ga ferromagnetic shape memory alloys
Authors: Cong D. Y. , Wang Y. D. , Xu J. Z. , Zuo L. , Zetterström P. , Delaplane R.
Published: December 2007

Crystal structure and phase transformation behaviors in two
Ni-Mn-Ga
ferromagnetic shape memory alloys (FSMAs) with compositions of
Ni48Mn30Ga22 and
Ni53Mn25Ga22 (at. %) as a function of temperature were investigated by in situ neutron diffraction experiments. Neutron diffraction technique proves to be highly efficient in characterizing structural transformation in
Ni-Mn-Ga
FSMAs, which consist of nearby elements in the periodic table. Our neutron results show that
Ni48Mn30Ga22 has a cubic, L21 Heusler structure from 373 to 293 K. Its crystal structure changes into a seven-layered orthorhombic martensitic structure when cooled to 243 K, and no further transformation is observed upon cooling to 19 K. Neutron diffraction results also show that
Ni53Mn25Ga22 has a tetragonal I4/mmm martensitic structure from 20 to 403 K. A pre-transformation around room temperature is observed from an abrupt jump in unit-cell volume of
Ni53Mn25Ga22, which corresponds with an endothermic peak detected in a heated DSC curve.
Identification of traditional Chinese medicine Costustoot by X-ray diffraction Fourier fingerprint pattern method
Authors: Ning-bo Gong , Yang Lu , Xiao-wei Zheng , Ji Zhang
Published: December 2007

X-ray powder diffraction was used to analyze and evaluate 11 samples of traditional Chinese medicine, Costustoot, found at various locations in China. A reference fingerprint pattern with 48 characteristic peaks for Costustoot was obtained from X-ray diffraction patterns of six Costustoots from the rhizomes of Aucklandia lappa Decne. The reference fingerprint pattern with 48 characteristic peaks for Costustoot was then used to evaluate the remaining five Costustoot materials. X-ray diffraction results show that the X-ray diffraction Fourier fingerprint pattern method can be used for rapid classification, identification, and quality control of Costustoots.
XRD characterization of texture and internal stress in electrodeposited copper films on Al substrates
Authors: Hong Bo , Jiang Chuan-hai , Wang Xin-jian
Published: December 2007

Internal stresses and textures of electroplated copper films (t=2, 8, 15, 30, 45, and 60) electrodeposited on Al substrates were studied using X-ray diffraction techniques. Results show that the stresses in the films are tensile. The 8 to 60 μm thick films have (220) fiber texture, in good agreement with strain energy minimization calculation. Results also show that a further rotational alignment of the fiber-textured grains was developed, and small amounts of the fiber-textured grains have their (2, −2, 0) planes aligned parallel to the flow direction of the electrodeposited currents. The degree of the rotation alignment increases with film thickness. Values of stress and the degree of texture of copper films were found to be adjustable using an ultrasound technique. Internal stress and the degree of the (220) texture decrease significantly by applying an ultrasound treatment during the electrodeposition process.
Crystal structure of microwave dielectric ceramics Ba[(Mg1−xCdx)0.33Nb0.67]O3
Authors: Deng J. X. , Xing X. R. , Chen J. , Yu R. B. , Liu G. R. , Meng J.
Published: December 2007

A series of complex perovskite solid solutions of
Ba[(Mg1−xCdx)0.33Nb0.67]O3 have been synthesized by the columbite method. Detailed Rietveld refinement of their X-ray diffraction data show that
Ba[(Mg1−xCdx)0.33Nb0.67]O3 has an order trigonal structure. The ordering degree as determined by the B-site occupancies increases with the partial substitution of Cd for Mg. However, a decrease in the ordering degree in the
Ba(Cd0.33Nb0.67)O3 sample is observed, which can be attributed to a relatively lower synthesis temperature. All the impurity phases are successfully identified by X-ray quantitative phase analysis. Dielectrics properties at low frequencies for all the
Ba[(Mg1−xCdx)0.33Nb0.67]O3 compounds have been measured successfully.
Powder X-ray diffraction and Rietveld analysis of Cd1−xCuxCr2O4(0.1≤x≤0.7)
Authors: Yan L. Q. , Jiang Z. W. , Peng X. D. , He L. H. , Wang F. W.
Published: December 2007

Structural properties of
Cd1−xCuxCr2O4(CCCO) have been investigated by means of X-ray powder diffraction and Rietveld analysis. A structural phase transformation from Fd3m to I42d at x=0.64 has been detected. The lattice constant a of the cubic unit cell decreases rapidly with increasing Cu content up to x=0.62. At x=0.64, the cubic unit cell is compressed into a tetragonal cell and
CrO6 octahedrons are distorted. With continuing Cu content increases above 0.64, the distortion of the unit cell is released slightly according to the changes in c/a. Magnetic properties of
Cd1−xCuxCr2O4(x=0.1,0.3,0.5,0.7) have also been measured and are discussed.
Thermal expansion of anatase and rutile between 300 and 575 K using synchrotron powder X-ray diffraction
Authors: Hummer D. R. , Heaney P. J. , Post J. E.
Published: December 2007

High-precision unit-cell parameters for the
TiO2 polymorphs anatase and rutile at temperatures between 300 and 575 K have been determined using Rietveld analysis of synchrotron powder XRD data. Polynomial models were used to express the tetragonal unit-cell parameters as a function of absolute temperature, with a (anatase)=1.759 37×10−8×T2+6.418 16×10−6×T+3.779 84, c (anatase)=6.6545×10−8×T2+4.0464×10−5×T+9.4910, V (anatase)=2.237 58×10−6×T2+1.027 77×10−3×T+135.602, a (rutile)=−6.636 42×10−11×T3+1.005 01×10−7×T2−1.009 9310−5×T+4.586 34, c (rutile)=−4.115 50×10−11×T3+6.405 94×10−8×T2+4.675 61×10−7T+2.951 81, and V (rutile)=−2.7790×10−9×T3+4.2386×10−6×T2−3.3551×10−4×T+62.100. The polynomial expressions were used to calculate linear (α) and volume (β) thermal expansion coefficients of anatase and rutile between 300 and 575 K. At 298.15 K, these values were αa=4.46943×10−6 K−1, αc=8.4283×10−6 K−1, and β=17.3542×10−6 K−1 for anatase, and αa=6.99953×10−6 K−1, αc=9.36625×10−6 K−1, and β=28.680×10−6 K−1 for rutile.
Rietveld refinement of ternary compound Gd117Fe52Ge112
Authors: He Wei , Zhang Jiliang , Zeng Lingmin
Published: December 2007

A new ternary compound
Gd117Fe52Ge112 has been successfully synthesized and studied by means of X-ray powder diffraction technique.
Gd117Fe52Ge112 crystallizes in a cubic
Tb117Fe52Ge112-type structure with space group Fm3m(#225) and lattice parameter a=28.7680(1) Å. Crystal structure of
Gd117Fe52Ge112 has been successfully refined using the Rietveld method from X-ray diffraction data. The R-factors for the Rietveld refinement are Rp=0.099 and Rwp=0.128. X-ray powder diffraction data with the figure of merit F30 of 80.4(30) are also reported.
Crystal structure and powder diffraction pattern of high-temperature modification of Pd73Sn14Te13
Authors: Laufek F. , Vymazalová A. , Plášil J.
Published: December 2007

Crystal structure of high-temperature modification of
Pd73Sn14Te13 has been refined by the Rietveld method from laboratory X-ray powder diffraction data. Refined crystallographic data of
Pd73Sn14Te13 are a=7.6456(3) Å, c=13.9575(9) Å, V=706.75(6) Å3, space group P63cm (No. 185), Z=6, and Dx=10.71 g/cm3. The title compound is isostructural with
Pd5Sb2 and
Ni5As2; it can be considered as a stacking and filling variant of the
Ni2In
structure. An important structural feature in the high-temperature modification of
Pd73Sn14Te13 is the presence of various
Pd-Pd
bonds.
X-ray powder diffraction investigation of new oxynitride precursors: rare earth oxide compounds of fluorite- and sheelite-type structures in the Yb-(Zr,W)-O system
Authors: Maillard Pascal , Bénard-Rocherullé Patricia , Roisnel Thierry , Tessier Franck
Published: December 2007

Nanocrystallized oxide precursors of colored (oxy)nitrides related to the system Yb-(Zr-W)-O have been successfully prepared using achimie douceprocess—the amorphous citrate route. The process involves first a formation of fine and homogeneous powdered solids obtained by calcination at 600 °C, a temperature much lower than that of the conventional solid-state method. At this stage, the X-ray diffraction patterns exhibit large line broadening effects. Finally, two well-crystallized and pure quaternary oxides have been readily obtained by heating and under annealing conditions at 850 and 900 °C for 12 h. For one of the patterns, all the X-ray diffraction lines can be easily indexed to a cubic phase with the fluorite structure conforming to theFm3mspace group [Yb2Zr1.21W0.41O6.65◻1.35called C-phase:a=5.1864(2) Å]. The second phase adopts the sheelite-type structure [Yb2ZrWO8called T-phase: space groupI41/a,a=5.1584(5), andc=10.8246(6) Å]. By taking into account the present compositions determined by EDS measurements, Rietveld structure refinements produce finalRBfactors of 0.015 and 0.044, andRwpfactors of 0.069 and 0.089, respectively. In order to characterize the microstructure of the materials (crystallite size and lattice distortion) at the nanometer scale, a study based on diffraction line broadening analysis applying the whole pattern refinement method was also undertaken with confidence. The results show smooth angular variations of the values of FWHMs, indicating that the microstructural properties are isotropic for the cubic and tetragonal oxides. More precisely, the results indicate that whatever the profile fitting approach used (“profile matching” procedure and Rietveld method), the reliability factorsRwpare systematically better with a combined size strain than with zero strain considerations. The strain magnitudes observed for the C-phase-850 °C as well as for the T-phase-900 °C should be viewed as realistic strain.
p38 MAPK Inhibition Reduces Aortic Ultrasmall Superparamagnetic Iron Oxide Uptake in a Mouse Model of Atherosclerosis
Authors: Morris Joanne B. , Olzinski Alan R. , Bernard Roberta E. , Aravindhan Karpagam , Mirabile Rosanna C. , Boyce Rogely , Willette Robert N. , Jucker Beat M.
Published: December 2007

Objective—

Ultrasmall superparamagnetic iron oxide (USPIO) contrast agents have been used for noninvasive MRI assessment of atherosclerotic plaque inflammation. The purpose of this study was to noninvasively evaluate USPIO uptake in aorta of apoE
−/−
mice and to determine the effects of Angiotensin II (Ang II) infusion and chronic antiinflammatory treatment with a p38 MAPK inhibitor on this uptake.

Methods and Results—

ApoE
−/−
mice were administered saline or Ang II (1.44 mg/kg/d) for 21 days. In vivo MRI assessment of USPIO uptake in the aortic arch was observed in all animals. However, although the Ang II group had significantly higher absolute iron content (↑103%,
P
<0.001) in the aortic arch compared with the saline group, the p38 MAPK inhibitor (SB-239063, 150 mg/kg/d) treatment group did not (↑6%, NS). The in vivo MRI signal intensity was significantly correlated to the absolute iron content in the aortic arch. Histological evaluation of the aortic root lesion area showed colocalization of USPIO with macrophages and a reduction in USPIO but not macrophage content with SB-239063 treatment.

Conclusion—

The present study demonstrates that noninvasive assessment of USPIO uptake, as a marker for inflammation in murine atherosclerotic plaque, is feasible and that p38 MAPK inhibition attenuates the uptake of USPIO in aorta of Ang II–infused apoE
−/−
mice.
Final Common Molecular Pathways of Aging and Cardiovascular Disease
Authors: Cosentino Francesco , Francia Pietro , Camici Giovanni G. , Pelicci Pier Giuseppe , Volpe Massimo , Lüscher Thomas F.
Published: December 2007

Oxidative stress affects the availability of key-regulators of vascular homeostasis and controls a number of signaling pathways relevant to myocardial and vascular disease. Reactive oxygen species are generated by different intracellular molecular pathways principally located in mitochondria. The notion that mice carrying a targeted mutation of the p66Shcgene display prolonged lifespan, reduced production of intracellular oxidants, and increased resistance to oxidative stress–induced apoptosis prompted a series of studies aimed at defining the biochemical function of p66Shcand its possible implication in cardiovascular diseases. Indeed, p66Shc−/−mice are protected against vascular, cardiac, and renal impairment attributable to hypercholesterolemia, aging, diabetes, and ischemia/reperfusion. The present review focuses on the biochemical and physiological function of the p66Shcadaptor protein as well as on the mechanisms linking p66Shc-associated generation of free radicals to the pathophysiology of aging and cardiovascular disease. On the whole, the evidence so far reported and here discussed supports the concept that pharmacological modulation of p66Shcexpression and activity may be a novel and effective target for the treatment of atherosclerotic vascular disease as well as myocardial adaptation to hypertrophic, inflammatory and neuro-hormonal stimuli in the overloaded heart.
Oxidant Generation Predominates Around Calcifying Foci and Enhances Progression of Aortic Valve Calcification
Authors: Liberman Marcel , Bassi Estêvão , Martinatti Marina Kamla , Lario Fábio Cerqueira , Wosniak João , Pomerantzeff Pablo M.A. , Laurindo Francisco R.M.
Published: December 2007

Objective—

We hypothesized that reactive oxygen species (ROS) contribute to progression of aortic valve (AV) calcification/stenosis.

Methods and Results—

We investigated ROS production and effects of antioxidants tempol and lipoic acid (LA) in calcification progression in rabbits given 0.5% cholesterol diet +10
4
IU/d Vit.D
2
for 12 weeks. Superoxide and H
2
O
2
microfluorotopography and 3-nitrotyrosine immunoreactivity showed increased signals not only in macrophages but preferentially around calcifying foci, in cells expressing osteoblast/osteoclast, but not macrophage markers. Such cells also showed increased expression of NAD(P)H oxidase subunits Nox2, p22phox, and protein disulfide isomerase. Nox4, but not Nox1 mRNA, was increased. Tempol augmented whereas LA decreased H
2
O
2
signals. Importantly, AV calcification, assessed by echocardiography and histomorphometry, decreased 43% to 70% with LA, but increased with tempol (
P
≤0.05). Tempol further enhanced apoptosis and Nox4 expression. In human sclerotic or stenotic AV, we found analogous increases in ROS production and NAD(P)H oxidase expression around calcifying foci. An in vitro vascular smooth muscle cell (VSMC) calcification model also exhibited increased, catalase-inhibitable, calcium deposit with tempol, but not with LA.

Conclusions—

Our data provide evidence that ROS, particularly hydrogen peroxide, potentiate AV calcification progression. However, tempol exhibited a paradoxical effect, exacerbating AV/vascular calcification, likely because of its induced increase in peroxide generation.
VE-Cadherin
Authors: Vestweber Dietmar
Published: December 2007

Vascular endothelial (VE)-cadherin is a strictly endothelial specific adhesion molecule located at junctions between endothelial cells. In analogy of the role of E-cadherin as major determinant for epithelial cell contact integrity, VE-cadherin is of vital importance for the maintenance and control of endothelial cell contacts. Mechanisms that regulate VE-cadherin–mediated adhesion are important for the control of vascular permeability and leukocyte extravasation. In addition to its adhesive functions, VE-cadherin regulates various cellular processes such as cell proliferation and apoptosis and modulates vascular endothelial growth factor receptor functions. Consequently, VE-cadherin is essential during embryonic angiogenesis. This review will focus on recent new developments in understanding the role of VE-cadherin in controlling endothelial cell contacts and influencing endothelial cell behavior by various outside-in signaling processes.
Upregulation of Pentraxin-3 in Human Endothelial Cells After Lysophosphatidic Acid Exposure
Authors: Gustin Cindy , Delaive Edouard , Dieu Marc , Calay Damien , Raes Martine
Published: December 2007

Objective—

The earliest event in atherogenesis appears to be endothelium dysfunction. Lysophosphatidic acid (LPA), one of the major bioactive lipid components of oxidized low-density lipoproteins (oxLDL), can cause the activation of endothelial cells (ECs), which start to secrete multiple proinflammatory polypeptides/proteins. The purpose of this study was to better document the proatherogenic properties of LPA using a subproteomic approach focused on the secretome of LPA-treated ECs.

Methods and Results—

The secretome of LPA-treated ECs was analyzed using the 2D-DIGE approach. Among the 20 spots displaying significant variations of abundance compared with the control cells, we identified pentraxin-3 by mass spectrometry. Pentraxin-3 upregulation was confirmed at the mRNA and protein level, both on immortalized and primary ECs. LPA- but also oxLDL-induced pentraxin-3 upregulation was reduced in the presence of an antagonist of the LPA-receptors and largely dependent on NFκB activation. Finally, we demonstrated, for the first time, the chemotactic activity of pentraxin-3 on human THP-1 monocytes by using a chemotaxis assay.

Conclusions—

Our findings favor the proatherogenic role of LPA, a bioactive lipid produced by activated platelets and present in oxLDL, because it enhances pentraxin-3 secretion that could contribute to the accumulation of monocytes in the atherosclerotic lesion.