bluuebunny/crossref_metadata_2025 huggingface dataset:
A Novel Structure and Cycle Performance of Co3O4-C prepared by Electro-codepositing as Negative Electrode for Lithium-ion Batteries
Authors: Yu Weiping , Wang Pengpeng , Yu Weiping , Zhang Ning , Zhang Ning
Published: May 2008

Co3O4-C negative electrode for lithium-ion batteries has been prepared by a electro-codepositing in 0.5mol/L Co(NO3)2+C solutions after sintered under 0.1atm vacuum at 245°C. Without carbon in the film, it has a 20~30 nm thick layer of Co3O4 with beehive-like structure. When the film contains 10.84% of carbon, it has a beehive-like structure that consists of composite Co3O4-C particles. When the film contains 32.76% of carbon, it was made up of some bulky carbon with Co3O4-C all around and a part of porous beehive with Co3O4-C composite needles inside. When the Co3O4-C and Li are assembled to simulative batteries, charged and discharged at 0.2C, film contains 32.76% of carbon has the best cycle performance, after charged/recharged 230 cycles, the charge specific capacity was 669.8 mAh•g-1, and the holding ratio was 100%; after charged/recharged 260 cycles, the charge specific capacity was decreased to 505.3 mAh•g-1, it still keeps partial beehive-like structure.
Experimental System for Studying Interfacial Electrochemistry at Temperatures Above 300oC
Authors: Balashov Victor , Fedkin Mark , Lvov Serguei , Dooley R. B.
Published: May 2008

A new experimental electrochemical system was developed for measuring corrosion rates in high temperature dilute electrolyte solutions. The system was tested at temperatures and pressures up to 350 oC and 20 MPa. The low corrosion rates in the aqueous boiler solutions are difficult to quantify using the traditional mass loss and metallography techniques. The newly designed electrochemical system with annular-duct flow-through working-counter electrode assembly was proved to be efficient for in-situ corrosion studies. The electrochemical impedance spectroscopy (EIS) methods were found the most applicable techniques to measure the corrosion current in the high temperature/very dilute electrolyte solutions at temperatures to 350 oC.
Crevice Corrosion Damage Evolution in High Temperature Brines
Authors: Payer Joe H. , Shan Xi , Agarwal Arun S. , Landau Uziel
Published: May 2008

The overall objective of this work is to provide deeper insight into chemical/electrochemical processes that control the initiation, propagation, stifling, and arrest of crevice corrosion. Crevice corrosion is an important degradation mode to be evaluated for corrosion performance of passive metals exposed to high temperature brines over long exposure periods. Both modeling and experimental work has been performed on the initiation and propagation of crevice corrosion. The requirements for the initiation and propagation of localized corrosion are analyzed and conditions for continued propagation are identified. Each of the components of the electrochemical corrosion cell can limit corrosion rates: electrolyte layer- resistance between the anode and cathode limits the current; cathode-current capacity cannot meet the anode demand; anode-current requirement for critical crevice chemistry stability is not met and anode/cathode-incompatibility of coupled processes for a given scenario.
A Mechanistic Understanding of Solid Oxide Fuel Cell Chemistry Through In-Situ Raman Spectroscopy
Authors: Pomfret Michael B. , Owrutsky Jeffrey , Walker Robert
Published: May 2008

Raman spectroscopy has been used in-situ to characterize graphitic intermediates formed by hydrocarbons fuels on porous Ni/YSZ SOFC anodes. Low molecular weight (MW), carbon containing fuels and fuel mixtures were chosen to isolate (and mimic) the contributions to SOFC performance from various species that form when higher MW species such as C4H10 undergo gas-phase pyrolysis prior to reaching SOFC anodes. Raman spectra of all mixtures display peaks at 1570 cm-1 and 1345 cm-1, assigned to the graphite G and D peaks, respectively. The D peak intensity is indicative of the amount of structural disorder in the graphite on the surface. A trend of increasing disorder with higher MW fuels mixes is observed. The electrochemical behavior of cells operated with C4H10 is duplicated when fuel mixtures contain ethylene and propylene.
Thin Film Electrochemical Deposition at Temperatures up to 180 {degree sign}C for Photovoltaic Applications
Authors: Levy-Clement Claude
Published: May 2008

This paper presents several examples of thin films synthesized by electrochemical deposition in view of their application in photovoltaic. An overview of the deposition of CdTe, d-SnS, Bi2S3, ZnO and CuInSe2 is given to illustrate the versatility of the electrodeposition method. CdTe/CdS and CuInSe2/CdS solar cells made by electrochemical methods are in the stage of pilot lines, while the research on ZnO/CdSe/CuSCN solar cell based on an advanced concept of sensitization of wide bandgap materials is briefly described.
Ion Adsorption on Metal Oxide Surfaces to Hydrothermal Conditions.
Authors: Wesolowski D. J. , Machesky Michael L. , Ridley Moira K. , Palmer Donald A. , Zhang Zhan , Fenter Paul A. , Predota Milan , Cummings Peter T.
Published: May 2008

In this article, we review the sorption of multivalent cations on rutile (alpha-TiO2) powder surfaces in aqueous 1:1 electrolyte media from room temperature to 250 degrees C. All cations are shown to occupy 'inner sphere' sorption sites in contact with surface oxygens and hydroxyl groups, as well as the diffuse portion of the electrical double layer (EDL). Sorption is shown to increase strongly with increasing temperature, and the sorption affinity is strongly-related to cation radius and charge. Macroscopic powder pH-titration results obtained with ORNL's high temperature hydrogen electrode concentration cells can be rationalized with Gouy-Chapman-Stern models of the EDL, augmented by atomic-scale structural and proton affinity data from synchrotron X-ray studies and computational modeling approaches.
Interfacial Chemistry of Hydrothermal Deposition of Zirconia on Metal Substrates
Authors: Zhou Zhuangfei , Chalkova Elena , Balashov Victor , Chou Peter , Lvov Serguei
Published: May 2008

The hydrothermally deposition process for applying zirconia coating onto metal substrates was studied at different conditions to understand better the interfacial chemistry of the coating formation. In this study, a new non-recirculating autoclave coating system, incorporating the precursor-supply-system, which delivered the solution with constant concentration, was designed. A number of operating parameters (temperature, pH of aqueous solution, oxidant concentration, solution hydrodynamics, and duration of deposition process) have been investigated in terms of their effect on the deposition of ZrO2 films. The coating quality was analyzed. The process window for formation of adherent coating appeared to be relatively narrow: solution temperature 190-200 ºC, the pH of the aqueous reservoir 5.3-7.5. Oxidant concentration affected coating adhesion rather than coating formation.
Understanding the Water Retention of Composite Proton Exchange Membranes Based on Surface Chemistry of Inorganic Fillers
Authors: Fedkin Mark , Chalkova Elena , Wesolowski D. J. , Lvov Serguei
Published: May 2008

Use of metal oxide additives is considered a viable option for improving thermal, chemical, and transport properties of the proton exchange membranes for fuel cells operating at elevated temperatures (>100 oC) and reduced relative humidity (<70%). The purpose of this paper is to review the characteristics of some specific oxide materials for fuel cell applications based on available experimental surface chemistry data and surface modeling. Several commonly used oxides were differentiated based on their thermodynamic solubility, surface charge, and states of the surface water. Surface charge is discussed as a primary factor controlling water retention by the composite membranes in dehydrating environments.
Modeling flow in collecting lymphatic vessels: one-dimensional flow through a series of contractile elements
Authors: Macdonald A. J. , Arkill K. P. , Tabor G. R. , McHale N. G. , Winlove C. P.
Published: May 2008

The lymphatic system comprises a series of elements, lymphangions, separated by valves and possessed of active, contractile walls to pump interstitial fluid from its collection in the terminal lymphatics back to the main circulation. Despite its importance, there is a dearth of information on the fluid dynamics of the lymphatic system. In this article, we describe linked experimental and computational work aimed at elucidating the biomechanical properties of the individual lymphangions. We measure the static and dynamic mechanical properties of excised bovine collecting lymphatics and develop a one-dimensional computational model of the coupled fluid flow/wall motion. The computational model is able to reproduce the pumping behavior of the real vessel using a simple contraction function producing fast contraction pulses traveling in the retrograde direction to the flow.
Diacylglycerol kinase-ε restores cardiac dysfunction under chronic pressure overload: a new specific regulator of Gαqsignaling cascade
Authors: Niizeki Takeshi , Takeishi Yasuchika , Kitahara Tatsuro , Arimoto Takanori , Ishino Mitsunori , Bilim Olga , Suzuki Satoshi , Sasaki Toshiki , Nakajima Osamu , Walsh Richard A. , Goto Kaoru , Kubota Isao
Published: May 2008

Gαqprotein-coupled receptor (GPCR) signaling pathway, which includes diacylglycerol (DAG) and protein kinase C (PKC), plays a critical role in cardiac hypertrophy. DAG kinase (DGK) catalyzes DAG phosphorylation and controls cellular DAG levels, thus acting as a regulator of GPCR signaling. It has been reported that DGKε acts specifically on DAG produced by inositol cycling. In this study, we examined whether DGKε prevents cardiac hypertrophy and progression to heart failure under chronic pressure overload. We generated transgenic mice with cardiac-specific overexpression of DGKε (DGKε-TG) using an α-myosin heavy chain promoter. There were no differences in cardiac morphology and function between wild-type (WT) and DGKε-TG mice at the basal condition. Either continuous phenylephrine infusion or thoracic transverse aortic constriction (TAC) was performed in WT and DGKε-TG mice. Increases in heart weight after phenylephrine infusion and TAC were abolished in DGKε-TG mice compared with WT mice. Cardiac dysfunction after TAC was prevented in DGKε-TG mice, and the survival rate after TAC was higher in DGKε-TG mice than in WT mice. Phenylephrine- and TAC-induced DAG accumulation, the translocation of PKC isoforms, and the induction of fetal genes were blocked in DGKε-TG mouse hearts. The upregulation of transient receptor potential channel (TRPC)-6 expression after TAC was attenuated in DGKε-TG mice. In conclusion, these results demonstrate the first evidence that DGKε restores cardiac dysfunction and improves survival under chronic pressure overload by controlling cellular DAG levels and TRPC-6 expression. DGKε may be a novel therapeutic target to prevent cardiac hypertrophy and progression to heart failure.
The transcriptional coactivator PGC-1α is essential for maximal and efficient cardiac mitochondrial fatty acid oxidation and lipid homeostasis
Authors: Lehman John J. , Boudina Sihem , Banke Natasha Hausler , Sambandam Nandakumar , Han Xianlin , Young Deanna M. , Leone Teresa C. , Gross Richard W. , Lewandowski E. Douglas , Abel E. Dale , Kelly Daniel P.
Published: May 2008

High-capacity mitochondrial ATP production is essential for normal function of the adult heart, and evidence is emerging that mitochondrial derangements occur in common myocardial diseases. Previous overexpression studies have shown that the inducible transcriptional coactivator peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α is capable of activating postnatal cardiac myocyte mitochondrial biogenesis. Recently, we generated mice deficient in PGC-1α (PGC-1α−/−mice), which survive with modestly blunted postnatal cardiac growth. To determine if PGC-1α is essential for normal cardiac energy metabolic capacity, mitochondrial function experiments were performed on saponin-permeabilized myocardial fibers from PGC-1α−/−mice. These experiments demonstrated reduced maximal (state 3) palmitoyl-l-carnitine respiration and increased maximal (state 3) pyruvate respiration in PGC-1α−/−mice compared with PGC-1α+/+controls. ATP synthesis rates obtained during maximal (state 3) respiration in permeabilized myocardial fibers were reduced for PGC-1α−/−mice, whereas ATP produced per oxygen consumed (ATP/O), a measure of metabolic efficiency, was decreased by 58% for PGC-1α−/−fibers. Ex vivo isolated working heart experiments demonstrated that PGC-1α−/−mice exhibited lower cardiac power, reduced palmitate oxidation, and increased reliance on glucose oxidation, with the latter likely a compensatory response.13C NMR revealed that hearts from PGC-1α−/−mice exhibited a limited capacity to recruit triglyceride as a source for lipid oxidation during β-adrenergic challenge. Consistent with reduced mitochondrial fatty acid oxidative enzyme gene expression, the total triglyceride content was greater in hearts of PGC-1α−/−mice relative to PGC-1α+/+following a fast. Overall, these results demonstrate that PGC-1α is essential for the maintenance of maximal, efficient cardiac mitochondrial fatty acid oxidation, ATP synthesis, and myocardial lipid homeostasis.
Cyclic AMP acts through Rap1 and JNK signaling to increase expression of cutaneous smooth muscle α2C-adrenoceptors
Authors: Eid A. H. , Chotani M. A. , Mitra S. , Miller T. J. , Flavahan N. A.
Published: May 2008

Cold increases cutaneous vasoconstriction by unmasking the contractile activity of α2C-adrenoceptors (α2C-ARs) in vascular smooth muscle cells (VSMCs), which is mediated by the cold-induced mobilization of α2C-ARs from the transGolgi to the cell surface. The expression of α2C-ARs in human cutaneous VSMCs is under dual regulation by cyclic AMP: gene transcription is inhibited by cyclic AMP acting through protein kinase A but is increased by cyclic AMP acting through the exchange protein directly activated by cyclic AMP (EPAC) and the GTP-binding protein Rap1. Experiments were performed to further characterize the Rap1 signaling pathway. Forskolin (10 μM), the selective EPAC activator, 8-pCPT-2′-O-Me-cyclic AMP (CMC; 100 μM), or a constitutively active mutant of Rap1 (Rap1CA) increased the activity of c-Jun NH2-terminal kinase (JNK) in human cutaneous VSMCs. This was associated with the increased phosphorylation of c-Jun and activation of an activator protein (AP)-1 reporter construct, which were inhibited by the JNK inhibitor SP600125 (3 μM). Rap1CA increased the activity of an α2C-AR promoter-reporter construct, which was inhibited by SP600125 (3 μM) or by the mutation of an AP-1 binding site in the α2C-AR promoter. Furthermore, forskolin (10 μM) or CMC (100 μM) increased the expression of the α2C-AR protein, and these effects were inhibited by SP600125 (3 μM). Therefore, cyclic AMP increases the expression of α2C-ARs in cutaneous VSMCs by activating a novel Rap1 signaling pathway, mediated by the activation of JNK, AP-1, and the subsequent transcriptional activation of the α2C-AR gene. By increasing the expression of cold-responsive α2C-ARs, this pathway may contribute to enhanced cold-induced vasoconstriction in the cutaneous circulation, including Raynaud's phenomenon.
Intracellular calcium dynamics at the core of endocardial stationary spiral waves in Langendorff-perfused rabbit hearts
Authors: Tang Liang , Hwang Gyo-Seung , Hayashi Hideki , Song Juan , Ogawa Masahiro , Kobayashi Kenzaburo , Joung Boyoung , Karagueuzian Hrayr S. , Chen Peng-Sheng , Lin Shien-Fong
Published: May 2008

In vitro models of sustained monomorphic ventricular tachycardia (MVT) are rare and do not usually show spiral reentry on the epicardium. We hypothesized that MVT is associated with the spiral wave in the endocardium and that this stable reentrant propagation is supported by a persistently elevated intracellular calcium (Cai) transient at the core of the spiral wave. We performed dual optical mapping of transmembrane potential ( Vm) and Cai dynamics of the right ventricular (RV) endocardium in Langendorff-perfused rabbit hearts ( n = 12). Among 64 induced arrhythmias, 55% were sustained MVT (>10 min). Eighty percent of MVT showed stationary spiral waves (>10 cycles, cycle length: 128 ± 14.6 ms) in the endocardial mapped region, anchoring to the anatomic discontinuities. No reentry activity was observed in the epicardium. During reentry, the amplitudes of Vm and Cai signals were higher in the periphery and gradually decreased toward the core. At the core, maximal Vm and Cai amplitudes were 42.95 ± 5.89% and 43.95 ± 9.46%, respectively, of the control ( P < 0.001). However, the trough of the Vm and Cai signals at the core were higher than those in the periphery, indicating persistent Vm and Cai elevations during reentry. BAPTA-AM, a calcium chelator, significantly reduced the maximal Cai transient amplitude and prevented sustained MVT and spiral wave formation in the mapped region. These findings indicate that endocardial spiral waves often anchor to anatomic discontinuities causing stable MVT in normal rabbit ventricles. The spiral core is characterized by diminished Vm and Cai amplitudes and persistent Vm and Cai elevations during reentry.
ACTH-induced hypertension is dependent on the ouabain-binding site of the α2-Na+-K+-ATPase subunit
Authors: Lorenz John N. , Loreaux Elizabeth L. , Dostanic-Larson Iva , Lasko Valerie , Schnetzer J. Renee , Paul Richard J. , Lingrel Jerry B
Published: May 2008

ACTH-induced-hypertension is commonly employed as a model of stress-related hypertension, and despite extensive investigation, the mechanisms underlying elevated blood pressure (BP) are not well understood. We have reported that ACTH treatment increases tail-cuff systolic pressure in wild-type mice but not in mutant mice expressing ouabain-resistant α2-Na+-K+-ATPase subunits (α2R/R mice). Since tail-cuff measurements involve restraint stress, the present study used telemetry to distinguish between an effect of ACTH on resting BP vs. an ACTH-enhanced stress response. We also sought to explore the mechanisms underlying ACTH-induced BP changes in mutant α2R/R mice vs. wild-type mice (ouabain-sensitive α2-Na+-K+-ATPase, α2S/S mice). Baseline BP was not different between the two genotypes, but after 5 days of ACTH treatment, BP increased in α2S/S (104.0 ± 2.6 to 117.7 ± 3.0 mmHg) but not in α2R/R mice (108.2 ± 3.2 to 111.5 ± 4.0 mmHg). To test the hypothesis that ACTH hypertension is related to inhibition of α2-Na+-K+-ATPase on vascular smooth muscle by endogenous cardiotonic steroids, we measured BP and regional blood flow. Results suggest a differential sensitivity of renal, mesenteric, and cerebral circulations to ACTH and that the response depends on the ouabain sensitivity of the α2-Na+-K+-ATPase. Baseline cardiac performance was elevated in α2S/S but not α2R/R mice. Overall, the data establish that the α2-Na+-K+-ATPase ouabain-binding site is of central importance in the development of ACTH-induced hypertension. The mechanism appears to be related to alterations in cardiac performance, and perhaps vascular tone in specific circulations, presumably caused by elevated levels of circulating cardiotonic steroids.
Xanthine oxidase and mitochondria contribute to vascular superoxide anion generation in DOCA-salt hypertensive rats
Authors: Viel Emilie C. , Benkirane Karim , Javeshghani Danesh , Touyz Rhian M. , Schiffrin Ernesto L.
Published: May 2008

Vascular superoxide anion (O2•−) levels are increased in DOCA-salt hypertensive rats. We hypothesized that the endothelin (ET)-1-induced generation of ROS in the aorta and resistance arteries of DOCA-salt rats originates partly from xanthine oxidase (XO) and mitochondria. Accordingly, we blocked XO and the mitochondrial oxidative phosphorylation chain to investigate their contribution to ROS production in mesenteric resistance arteries and the aorta from DOCA-salt rats. Systolic blood pressure rose in DOCA-salt rats and was reduced after 3 wk by apocynin [NAD(P)H oxidase inhibitor and/or radical scavenger], allopurinol (XO inhibitor), bosentan (ETA/B receptor antagonist), BMS-182874 (BMS; ETA receptor antagonist), and hydralazine. Plasma uric acid levels in DOCA-salt rats were similar to control unilaterally nephrectomized (UniNx) rats, reduced with allopurinol and bosentan, and increased with BMS. Levels of thiobarbituric acid-reacting substances were increased in DOCA-salt rats versus UniNx rats, and BMS, bosentan, and hydralazine prevented their increase. Dihydroethidium staining showed reduced O2•− production in mesenteric arteries and the aorta from BMS- and bosentan-treated DOCA-salt rats compared with untreated DOCA-salt rats. Increased O2•− derived from XO was reduced or prevented by all treatments in mesenteric arteries, whereas bosentan and BMS had no effect on aortas from DOCA-salt rats. O2•− generation decreased with in situ treatment by tenoyltrifluoroacetone and CCCP, inhibitors of mitochondrial electron transport complexes II and IV, respectively, whereas rotenone (mitochondrial complex I inhibitor) had no effect. Our findings demonstrate the involvement of ETA receptor-modulated O2•− derived from XO and from mitochondrial oxidative enzymes in arteries from DOCA-salt rats.
Chronic doxycycline exposure accelerates left ventricular hypertrophy and progression to heart failure in mice after thoracic aorta constriction
Authors: Vinet Laurent , Rouet-Benzineb Patricia , Marniquet Xavier , Pellegrin Noémie , Mangin Laurence , Louedec Liliane , Samuel Jane-Lise , Mercadier Jean-Jacques
Published: May 2008

Tetracycline is a powerful tool for controlling the expression of specific transgenes (TGs) in various tissues, including heart. In these mouse systems, TG expression is repressed/enhanced by adding doxycycline (Dox) to the diet. However, Dox has been shown to attenuate matrix metalloproteinase (MMP) expression and activity in various tissues, and MMP inactivation mitigates left ventricular (LV) remodeling in animal models of heart failure. Therefore, we examined the influence of Dox on LV remodeling and MMP expression in mice after transverse aortic constriction (TAC). One month after TAC, cardiac hypertrophy (99% vs. 67%) and the proportion of mice exhibiting congestive heart failure (CHF, 74% vs. 32%) were higher in the TAC + Dox group than in the TAC group ( P < 0.05). These differences were no longer seen 2 mo after TAC, although LV was more severely dilated in TAC + Dox mice than in TAC mice ( P < 0.05). One month after TAC, the increase in brain natriuretic peptide and β-myosin heavy chain mRNA levels was 1.6 and 1.7 times higher, respectively, in TAC + Dox mice than in TAC mice ( P < 0.01). MMP-2 gelatin zymographic activity increased 1.9- and 2.4-fold in TAC and TAC + Dox mice, respectively ( P < 0.01 and P < 0.05 relative to respective sham-operated animals), but the difference between TAC + Dox and TAC mice did not reach statistical significance. Dox did not significantly alter TAC-associated perivascular and interstitial myocardial fibrosis. These findings demonstrate that Dox accelerates the onset of cardiac hypertrophy and the progression to CHF following TAC in mice. Accordingly, care should be taken when designing and interpreting studies based on TG mouse models of LV hypertrophy using the tetracycline-regulated (tet)-on/tet-off system.
Inhibition of brain proinflammatory cytokine synthesis reduces hypothalamic excitation in rats with ischemia-induced heart failure
Authors: Kang Yu-Ming , Zhang Zhi-Hua , Xue Baojian , Weiss Robert M. , Felder Robert B.
Published: May 2008

The expression of proinflammatory cytokines increases in the hypothalamus of rats with heart failure (HF). The pathophysiological significance of this observation is unknown. We hypothesized that hypothalamic proinflammatory cytokines upregulate the activity of central neural systems that contribute to increased sympathetic nerve activity in HF, specifically, the brain renin-angiotensin system (RAS) and the hypothalamic-pituitary-adrenal (HPA) axis. Rats with HF induced by coronary ligation and sham-operated controls (SHAM) were treated for 4 wk with a continuous intracerebroventricular infusion of the cytokine synthesis inhibitor pentoxifylline (PTX, 10 μg/h) or artificial cerebrospinal fluid (VEH). In VEH-treated HF rats, compared with VEH-treated SHAM rats, the hypothalamic expression of proinflammatory cytokines was increased, along with key components of the brain RAS (renin, angiotensin-converting enzyme, angiotensin type 1 receptor) and corticotropin-releasing hormone, the central indicator of HPA axis activation, in the paraventricular nucleus (PVN) of the hypothalamus. The expression of other inflammatory/excitatory mediators (superoxide, prostaglandin E2) was also increased, along with evidence of chronic neuronal excitation in PVN. VEH-treated HF rats had higher plasma levels of norepinephrine, ANG II, interleukin (IL)-1β, and adrenocorticotropic hormone, increased left ventricular end-diastolic pressure, and increased wet lung-to-body weight ratio. With the exception of plasma IL-1β, an indicator of peripheral proinflammatory cytokine activity, all measures of neurohumoral excitation were significantly lower in HF rats treated with intracerebroventricular PTX. These findings suggest that the increase in brain proinflammatory cytokines observed in rats with ischemia-induced HF is functionally significant, contributing to neurohumoral excitation by activating brain RAS and the HPA axis.
Triglyceride-rich lipoprotein lipolysis increases aggregation of endothelial cell membrane microdomains and produces reactive oxygen species
Authors: Wang Limin , Sapuri-Butti Annapoorna R. , Aung Hnin Hnin , Parikh Atul N. , Rutledge John C.
Published: May 2008

Triglyceride-rich lipoprotein (TGRL) lipolysis may provide a proinflammatory stimulus to endothelium. Detergent-resistant plasma membrane microdomains (lipid rafts) have a number of functions in endothelial cell inflammation. The mechanisms of TGRL lipolysis-induced endothelial cell injury were investigated by examining endothelial cell lipid rafts and production of reactive oxygen species (ROS). Lipid raft microdomains in human aortic endothelial cells were visualized by confocal microscopy with fluorescein isothiocyanate-labeled cholera toxin B as a lipid raft marker. Incubation of Atto565-labeled TGRL with lipid raft-labeled endothelial cells showed that TGRL colocalized with the lipid rafts, TGRL lipolysis caused clustering and aggregation of lipid rafts, and colocalization of TGRL remnant particles on the endothelial cells aggregated lipid rafts. Furthermore, TGRL lipolysis caused translocation of low-density lipoprotein receptor-related protein, endothelial nitric oxide synthase, and caveolin-1 from raft regions to nonraft regions of the membrane 3 h after treatment with TGRL lipolysis. TGRL lipolysis significantly increased the production of ROS in endothelial cells, and both NADPH oxidase and cytochrome P-450 inhibitors reduced production of ROS. Our studies suggest that alteration of lipid raft morphology and composition and ROS production could contribute to TGRL lipolysis-mediated endothelial cell injury.
Reduced heart size and increased myocardial fuel substrate oxidation in ACC2 mutant mice
Authors: Essop M. Faadiel , Camp Heidi S. , Choi Cheol Soo , Sharma Saumya , Fryer Ryan M. , Reinhart Glenn A. , Guthrie Patrick H. , Bentebibel Assia , Gu Zeiwei , Shulman Gerald I. , Taegtmeyer Heinrich , Wakil Salih J. , Abu-Elheiga Lutfi
Published: May 2008

The cardiac-enriched isoform of acetyl-CoA carboxylase (ACC2) is a key regulator of mitochondrial fatty acid (FA) uptake via carnitine palmitoyltransferase 1 (CPT1). To test the hypothesis that oxidative metabolism is upregulated in hearts from animals lacking ACC2 (employing a transgenic Acc2-mutant mouse), we assessed cardiac function in vivo and determined rates of myocardial substrate oxidation ex vivo. When examined by echocardiography, there was no difference in systolic function, but left ventricular mass of the Acc2-mutant (MUT) mouse was significantly reduced (∼25%) compared with wild-types (WT). Reduced activation of the mammalian target of rapamycin (mTOR) and its downstream target p70S6K was found in MUT hearts. Exogenous oxidation rates of oleate were increased ∼22%, and, unexpectedly, exogenous glucose oxidation rates were also increased in MUT hearts. Using a hyperinsulinemic-euglycemic clamp, we found that glucose uptake in MUT hearts was increased by ∼83%. Myocardial triglyceride levels were significantly reduced in MUT vs. WT while glycogen content was the same. In parallel, transcript levels of PPARα and its target genes, pyruvate dehydrogenase kinase-4 (PDK-4), malonyl-CoA decarboxylase (MCD), and mCPT1, were downregulated in MUT mice. In summary, we report that 1) Acc2-mutant hearts exhibit a marked preference for the oxidation of both glucose and FAs coupled with greater utilization of endogenous fuel substrates (triglycerides), 2) attenuated mTOR signaling may result in reduced heart sizes observed in Acc2-mutant mice, and 3) Acc2-mutant hearts displayed normal functional parameters despite a significant decrease in size.
Localized elasticity measured in epithelial cells migrating at a wound edge using atomic force microscopy
Authors: Wagh Ajay A. , Roan Esra , Chapman Kenneth E. , Desai Leena P. , Rendon David A. , Eckstein Eugene C. , Waters Christopher M.
Published: May 2008

Restoration of lung homeostasis following injury requires efficient wound healing by the epithelium. The mechanisms of lung epithelial wound healing include cell spreading and migration into the wounded area and later cell proliferation. We hypothesized that mechanical properties of cells vary near the wound edge, and this may provide cues to direct cell migration. To investigate this hypothesis, we measured variations in the stiffness of migrating human bronchial epithelial cells (16HBE cells) ∼2 h after applying a scratch wound. We used atomic force microscopy (AFM) in contact mode to measure the cell stiffness in 1.5-μm square regions at different locations relative to the wound edge. In regions far from the wound edge (>2.75 mm), there was substantial variation in the elastic modulus in specific cellular regions, but the median values measured from multiple fields were consistently lower than 5 kPa. At the wound edge, cell stiffness was significantly lower within the first 5 μm but increased significantly between 10 and 15 μm before decreasing again below the median values away from the wound edge. When cells were infected with an adenovirus expressing a dominant negative form of RhoA, cell stiffness was significantly decreased compared with cells infected with a control adenovirus. In addition, expression of dominant negative RhoA abrogated the peak increase in stiffness near the wound edge. These results suggest that cells near the wound edge undergo localized changes in cellular stiffness that may provide signals for cell spreading and migration.
The inhaled Rho kinase inhibitor Y-27632 protects against allergen-induced acute bronchoconstriction, airway hyperresponsiveness, and inflammation
Authors: Schaafsma Dedmer , Bos I. Sophie T. , Zuidhof Annet B. , Zaagsma Johan , Meurs Herman
Published: May 2008

Recently, we have shown that allergen-induced airway hyperresponsiveness (AHR) after the early (EAR) and late (LAR) asthmatic reaction in guinea pigs could be reversed acutely by inhalation of the Rho kinase inhibitor Y-27632. The present study addresses the effects of pretreatment with inhaled Y-27632 on the severity of the allergen-induced EAR and LAR, the development of AHR after these reactions, and airway inflammation. Using permanently instrumented and unrestrained ovalbumin (OA)-sensitized guinea pigs, single OA challenge-induced EAR and LAR, expressed as area under the lung function (pleural pressure, Ppl) time-response curve, were measured, and histamine PC100(provocation concentration causing a 100% increase of Ppl) values were assessed 24 h before, and at 6 and 24 h after, the OA challenge (after the EAR and LAR, respectively). Thirty minutes before and 8 h after OA challenge, saline or Y-27632 (5 mM) was nebulized. After the last PC100value, bronchoalveolar lavage (BAL) was performed, and the inflammatory cell profile was determined. It was demonstrated that inhalation of Y-27632 before allergen challenge markedly reduced the immediate allergen-induced peak rise in Ppl, without significantly reducing the overall EAR and LAR. Also, pretreatment with Y-27632 considerably protected against the development of AHR after the EAR and fully prevented AHR after the LAR. These effects could not be explained by a direct effect of Y-27632 on the histamine responsiveness, because of the short duration of the acute bronchoprotection of Y-27632 (<90 min). In addition, Y-27632 reduced the number of total inflammatory cells, eosinophils, macrophages, and neutrophils recovered from the BAL. Altogether, inhaled Y-27632 protects against acute allergen-induced bronchoconstriction, development of AHR after the EAR and LAR, and airway inflammation in an established guinea pig model of allergic asthma.
Transforming growth factor-β signaling mediates hypoxia-induced pulmonary arterial remodeling and inhibition of alveolar development in newborn mouse lung
Authors: Ambalavanan Namasivayam , Nicola Teodora , Hagood James , Bulger Arlene , Serra Rosa , Murphy-Ullrich Joanne , Oparil Suzanne , Chen Yiu-Fai
Published: May 2008

Hypoxia causes abnormal neonatal pulmonary artery remodeling (PAR) and inhibition of alveolar development (IAD). Transforming growth factor (TGF)-β is an important regulator of lung development and repair from injury. We tested the hypothesis that inhibition of TGF-β signaling attenuates hypoxia-induced PAR and IAD. Mice with an inducible dominant-negative mutation of the TGF-β type II receptor (DNTGFβRII) and nontransgenic wild-type (WT) mice were exposed to hypoxia (12% O2) or air from birth to 14 days of age. Expression of DNTGFβRII was induced by 20 μg/g ZnSO4given intraperitoneally daily from birth. PAR, IAD, cell proliferation, and expression of extracellular matrix (ECM) proteins were assessed. In WT mice, hypoxia led to thicker, more muscularized resistance pulmonary arteries and impaired alveolarization, accompanied by increases in active TGF-β and phosphorylated Smad2. Hypoxia-induced PAR and IAD were greatly attenuated in DNTGFβRII mice given ZnSO4compared with WT control mice and DNTGFβRII mice not given ZnSO4. The stimulatory effects of hypoxic exposure on pulmonary arterial cell proliferation and lung ECM proteins were abrogated in DNTGFβRII mice given ZnSO4. These data support the conclusion that TGF-β plays an important role in hypoxia-induced pulmonary vascular adaptation and IAD in the newborn animal model.
The porcine lung as a potential model for cystic fibrosis
Authors: Rogers Christopher S. , Abraham William M. , Brogden Kim A. , Engelhardt John F. , Fisher John T. , McCray Paul B. , McLennan Geoffrey , Meyerholz David K. , Namati Eman , Ostedgaard Lynda S. , Prather Randall S. , Sabater Juan R. , Stoltz David Anthony , Zabner Joseph , Welsh Michael J.
Published: May 2008

Airway disease currently causes most of the morbidity and mortality in patients with cystic fibrosis (CF). However, understanding the pathogenesis of CF lung disease and developing novel therapeutic strategies have been hampered by the limitations of current models. Although the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) has been targeted in mice, CF mice fail to develop lung or pancreatic disease like that in humans. In many respects, the anatomy, biochemistry, physiology, size, and genetics of pigs resemble those of humans. Thus pigs with a targeted CFTR gene might provide a good model for CF. Here, we review aspects of porcine airways and lung that are relevant to CF.
Combating Methamphetamine Use in the Community
Authors: Listwan Shelley Johnson , Shaffer Deborah Koetzle , Hartman Jennifer L.
Published: May 2008

Methamphetamine use was historically a problem facing Western states; however, in recent years it has methodically spread throughout the nation. Methamphetamine use impacts communities, families, and the criminal justice system in a variety of ways. As such, many jurisdictions are developing policies to reduce the sale and consumption of this drug as well as increase penalties for its use. The question of whether methamphetamine users can be safely and effectively treated in the community is unresolved. This study explores whether community-based drug courts are a reasonable option for treating this population. Results of the study indicate that drug of choice does not influence outcome in a drug court setting. Policy implications are discussed.
Evaluating Awareness of Registered Sex Offenders in the Neighborhood
Authors: Craun Sarah W.
Published: May 2008

The goal of sex offender registration is to protect residents from recidivistic sexual offenders by providing public information about local offenders. This study determines what percentage of residents living near registered sex offenders are aware of the offenders and the predictors of awareness. The investigational group includes randomly selected residents, who completed surveys, living within one-tenth of a mile of registered sex offenders. A control group—those without sex offenders nearby—is included to see if residents believe offenders to be in every neighborhood. Significantly more investigational group respondents report that a sex offender lives in the neighborhood (31% vs. 2%). Hierarchical linear modeling confirms both individual and neighborhood predictors of awareness.
Controlling the Black School-Age Male
Authors: Fitzgerald Terence D.
Published: May 2008

Public schools have historically embedded mechanisms for control within their policies and procedures through a variety of means. This article investigates a moderately sized integrated public school system in an upscale to low socioeconomic Big Ten university community in Illinois. Through descriptive measures, the author examines the racial ramifications of using psychotropic medications (e.g., Ritalin) to control the undesired academic and social behavior of Black school-age boys. The study examines how federal policies (i.e., the Individuals with Disabilities Education Act of 1990 and Section 504) have allowed for the introduction of disproportionate behavioral-stimulant use with Black males as a mode for social control. This article situates findings within a larger argument regarding the ways in which racism and reproduction of the racialized social structure, from the inception of the United States through the 21st century, have included a cycle of control targeting Blacks, and specifically Black males.
A Mixed-Method Study of Teachers' Attitudes About Teaching in Urban and Low-Income Schools
Authors: Halvorsen Anne-Lise , Lee Valerie E. , Andrade Fernando H.
Published: May 2008

This multimethod study investigates the attitudes teachers in urban and low-income schools have about teaching early elementary students. The authors examine the contextual characteristics of elementary schools where such teachers are willing to take responsibility for children's learning. The quantitative analyses focus on a subsample of students and teachers in low-income schools from The Early Childhood Longitudinal Study—Kindergarten cohort. The qualitative data are drawn from a 2-year intensive study of eight kindergarten teachers and four first-grade teachers in urban public schools, with a focus on interviews with a subset of “highly responsible” teachers. The authors discuss policy implications, especially related to how to improve teachers' attitudes toward children from low-income environments.
Technological Innovation as Social Innovation
Authors: Núñez Jover Jorge , López Cerezo José Antonio
Published: May 2008

This article describes and analyzes the process of institutionalizing studies on science, technology, and society (STS) in Cuba, and the social and academic circumstances in which these studies are implemented there. The authors give a brief account of how science and technology have evolved in Cuba over the last four decades. The authors argue that the promotion of science and technological innovation in Cuba has purposely taken the form of social innovation. The authors offer our view of how the changes and demands on science, technology, and education can take advantage of the approaches and proposals of STS studies. The authors consider the traditions of thought that have influenced Cuban culture and construct a specific conceptual framework through which contemporary developments in STS are assimilated. Finally, on the basis of the above analysis, the authors describe experiences of the institutionalization of STS and their underlying objectives.
Structure of Glycerol and Cellulose Fiber Modified Water-Blown Soy Polyol-Based Polyurethane Foams
Authors: Banik Indranil , Sain Mohini M.
Published: May 2008

In this brief report, the effects of reinforcing agents, glycerol and refined cellulose fiber, have been studied on the foaming reactions of polyurethane based on polyol derived from soy bean oil. The presence of glycerol and cellulose fiber has been observed to have a considerable influence on the density of the foams. Changes in density of different foams have been correlated with the chemical structures generated in the presence of the components, and analyzed by fourier transform infrared (FTIR) spectroscopic study and thermogravimetric analysis (TGA). Scanning electron microscopic (SEM) observations are in line with the modifications induced by the reinforcing components.
Statistical Analysis of Delamination in Drilling Glass Fiber-Reinforced Plastics (GFRP)
Authors: Palanikumar K. , Rubio J. Campos , Abrão A. , Esteves A. , Davim J. Paulo
Published: May 2008

Fiber-reinforced composites are widely recognized for their superior mechanical properties and advantages for applications in aerospace, defence and transportation sectors. Delamination is a problem associated with drilling fiber-reinforced composite materials. In this work, the effects of feed speed, rotational speed and drill geometry on the resulting delamination factor are comparable in spite of the drill point angle used. A mathematical model is proposed to predict delamination in drilling glass fiber-reinforced plastic composites.
Feasibility of Using Heat Treated Wood in Wood/Thermoplastic Composites
Authors: Kaboorani Alireza , Faezipour Mehdi , Ebrahimi Ghanbar
Published: May 2008

Using wood and other natural fibers with thermoplastic materials is always associated with a problem: poor compatibility between wood fibers and thermoplastic matrix. This paper deals with the mentioned problem and tries to solve, or at least ease, it through pre-heat treatment of wood prior to blending of wood fibers with other components of composites. In this study, wood pre-heat treated at different temperatures (175, 190 and 205°C) was used at various loadings (25 and 50%) with high density polyethylene (HDPE) and polypropylene-maleic anhydride copolymer (MAPP) to produce composites. The composite properties, including mechanical performance and morphological character, were investigated. The results of this study show that pre-heat treatment temperature and coupling agent content did not impact the composite properties at 25% wood content. Adding treated wood at 50% level to the composites enhanced the mechanical properties in comparison with untreated wood. The degree of the enhancement depended on pre-heat treatment temperature. Using wood treated at 190°C resulted in composites with the highest modulus of rupture (MOR) and tensile strength. In terms of modulus of elasticity (MOE), composites having wood treated at 205°C showed the highest MOE in both tensile and flexural tests. Adding 2% coupling agent caused an improvement in modulus of rupture (MOR) and tensile strength. An increase in wood content from 25 to 50% deceased strain at maximum load drastically. Morphological study showed that the mode of fracture is a function of wood and coupling agent content, and pre-heat treatment temperature.
Numerical Modeling of Concrete Cylinders Confined with CFRP Composites
Authors: Sadeghian Pedram , Rahai Ali R. , Ehsani Mohammad R.
Published: May 2008

This article presents the results of numerical analyses of concrete cylinders (i.e., columns) confined in composites jackets. The specimens were subjected to uniaxial compression and the analysis was carried out using a non-linear finite element method. Various parameters such as wrap thickness, fiber orientation, concrete strength, and interfacial bonding were considered. Three different wrap thicknesses (0.9, 1.8, and 2.7mm), fiber orientation of 0°, ±15°, ±30°, and ±45° with respect to the hoop direction, and concrete strength values ranging from 20 MPa to 40 MPa were investigated. The finite element analysis results were in good agreement with experimental data presented by other researchers. The numerical analysis results demonstrated significant enhancement in the compressive strength, stiffness, and ductility of the CFRP-wrapped concrete cylinders compared to unconfined concrete cylinders. The stress—strain response of cylinders was greatly affected by analysis parameters.
Failure Analysis of Bolted Joints in Foam-core Sandwich Composites
Authors: Zabihpoor Mahmood , Moslemian Ramin , Afshin Mehdi , Nazemi Mohammad Hassan
Published: May 2008

This study represents an effort to predict the bearing strength, failure modes, and failure load of bolted joints in foam-core sandwich composites. The studied joints have been used in a light full composite airplane. By using solid laminates, a new design for the joint zone is developed. These solid laminates include a number of glass plies with total thickness equal to core thickness. The effect of solid laminate size and interface angle of foam—solid laminate in the bonding zone on the bearing strength, failure loads and type of modes are investigated. The numerical study is performed using 3D FEM in ANSYS commercial code. Tsai—Wu failure criterion is used in the failure analysis. The results indicate that the most important parameter in the proposed joint zone design is the foam—solid laminate interface angle which plays an important role on the value of failure criterion (damage) in the bonding zone. Also, the use of squared shaped solid laminate as compared with a circular laminate will decrease the criterion value significantly. Finally, the influence of solid laminate size and interface angle on the buckling strength was discussed. As obtained through eigenvalue buckling analysis, the increase of solid laminate size or interface angle could result in considerable higher buckling strength.
The Elastic Properties of Sandwich Structure with Z-pinned Foam Core
Authors: Du L. , Jiao Guiqiong  , Huang Tao
Published: May 2008

Z-pinned foam core sandwich is a novel structural material. It is produced by reinforcing lightweight foam core with a truss network of pultruded carbon fiber rods and then laminated between composite face sheets. This investigation presents an approach to obtain the equivalent moduli of Z-pin reinforced foam core. The pins are treated as cylinder inclusions in foam at the same time they act as truss core. Based upon the Mori—Tanaka mean-field theory to account for the interaction between the pins and foam, an analytical approach is developed to assess the effective moduli of foam containing randomly oriented pins. Under the concept of space truss frame, a homogenization model is presented to calculate the effective elastic properties of pins truss core. First-order shear theory is developed to simulate the mechanical behaviors of a Z-pin reinforced foam core sandwich. Then, core shear tests were carried out to check the validity of a theoretical model. Furthermore, numerical examples have been given for a carbon fiber pins reinforced Rohacell foam core. Analysis results indicate that the equivalent moduli of reinforced core are strongly affected by the orientation, the volume fraction, and the properties of Z-pins.