bluuebunny/crossref_metadata_2025 huggingface dataset:
Functionalization of Single-Walled Carbon Nanotubes with a Redox Active and Acid/Base Responsive TTFV Polymer
Authors: Liang Shuai , Chen Guang , Peddle Jessica , Zhao Yuming
Published: May 2012

A tetrathiafulvalene vinylogue (TTFV) and phenylacetylene based conjugated polymer was designed and synthesized. The polymer backbone can reversibly fold and unfold under the control of redox and acid/base stimuli. This conformational switching property allows the polymer to reversibly disperse and release single-walled carbon nanotubes in organic solvents in a controlled manner, which in turn offers a new non-covalent functionalization method for single-walled carbon nanotube processing.
Gold Nanoparticles Decorating Carbon Nanotubes toward Organic Solar Cells
Authors: Abdel-Fattah Tarek M.
Published: May 2012

Multi-walled carbon nanotubes (MWCNTs) were fabricated by chemical vapor deposition (CVD) using iron oxides as catalysts. The resulted MWCNTs were oxidized by nitric acid to form functionalized MWCNTs with carboxylic acid function groups (-COOH). Also, we synthesized 20 nm gold nanoparticles (AuNPs) by reducing Hydrogen tetrachloroaurate (HAuCl4) using citrates solution. The resultant AuNPs were coated with anionic species of citrate ions as the dispersant. By electrostatic interaction, the MWCNTs-COOH could be successfully coated with about 20 nm gold nanoparticles. Transmission electron spectroscopy (TEM) was used to characterize the morphology MWNTs, AuNPs and the resultant MWCNTs decorated gold nanoparticles.
Characterization of Copper Nanostructures Grown on Porous Silicon by Displacement Deposition
Authors: Bandarenka Hanna , Petrovich Vladimir , Komar Olga , Nenzi Paolo , Balucani Marco , Bondarenko Vitaly
Published: May 2012

Different copper nanostructures have been deposited onto porous silicon (PS) by using HF-based solutions of CuSO4 and immersion technique. The variation of the porous template parameters and deposition regimes has been found to allow obtaining of copper nanoparticles, copper rough films and porous copper layers. The dimensions, roughness, structural parameters and phase composition of the obtained copper nanostructures have been established.
Robust Ultrathin (20-25 nm)Trilayer Dielectric Low k Cu Damascene Cap for Sub-30 nm Nanoelectric Devices
Authors: Nguyen Son V. , Haigh Thomas , Tagami Masayoshi , Grill Alfred , Cohen Stephan , Shobha Hosadurga , Hu Chao-Kun , Adams Ed , Liniger Eric , Shaw Thomas , Cheng Tien , Yusuff Hakeem , Xu Yiheng , Ko Tze-Man , Molis Steven , Spooner Terry , Skordas Spyridon , Liu Xiao Hu , Bonilla Griselda , Edelstein Dan
Published: May 2012

Robust ultrathin (20 nm) trilayer low k SiNx/SiNy/SiCNH dielectric Cu caps (k ~4.0-4.2) with post ultraviolet (UV) cure compressive stress were developed and integrated into 22nm CMOS Back End Of Line (BEOL) devices. The new cap reduces device's capacitance (~ 4 %) and enhances stress stability in Cu-Ultra low k structures
Conformal EL Ni Fill in Through-Silicon-Via for 3D Interconnects
Authors: Tiwari Chandra S.
Published: May 2012

Through-silicon-via (TSV) metallization is a key step in 3D interconnects. Cu electroplating has been the primarily focus for this application from the semiconductor industry. Electroless nickel has been developed as an alternative to Cu electroplating; however, because vias are quite deep, achieving good step coverage within the vias has presented a considerable challenge. This paper presents a new electroless process; that yields good step coverage performance.
A "Looking Glass" into Electrolyte Properties: Cyclic Carbonate and Ester-LiClO4 Mixtures
Authors: Seo Daniel M. , Afroz Taliman , Ly Quang D. , O'Connell Michael , Boyle Paul D. , Henderson Wesley A.
Published: May 2012

Phase diagrams have been prepared for cyclic carbonate and ester mixtures with LiClO4. A Raman analysis of the mixtures enables the determination of the degree of solvation of the Li+ cations. Key insight into the link between solvent structure and solvation is obtained. It was discoverd that GBL solvates Li+ cations more effectively than EC despite having a lower permittivity than EC.
Solvent-LiBF4 Phase Diagrams, Ionic Association and Solubility - Cyclic Carbonates and Lactones
Authors: Allen Joshua L. , Seo Daniel M. , Ly Quang D. , Boyle Paul D. , Henderson Wesley A.
Published: May 2012

In this study, LiBF4 mixtures with the cyclic carbonate ethylene carbonate (EC) and ester γ-butyrolactone (GBL) have been investigated. To determine how the physical properties of these electrolytes are influenced by the solvation that exists, a multi-step process has been employed. Each system has been tested via DSC analysis to produce phase diagrams. From the phase diagrams, single crystal solvates were obtained and analyzed using XRD analysis to determine the solvate structures that are present in the solid-state. Raman spectroscopy was used to determine the degree of solvation that is present in the liquid electrolytes, which may then be directly correlated to the physical properties of the electrolyte.
Delving into the Properties and Solution Structure of Nitrile-Lithium Difluoro(Oxalato)Borate (LiDFOB) Electrolytes for Li-Ion Batteries
Authors: Han Sang-Don , Allen Joshua L. , Boyle Paul D. , Henderson Wesley A.
Published: May 2012

The phase diagram of acetonitrile-LiDFOB mixtures was determined. Raman spectroscopic analysis of the DFOB- anion vibrational bands indicates that a diverse range of solvates are present in solution. As demonstrated here, an in-depth analysis of (AN)n-LiDFOB electrolyte mixtures through the combination of the phase diagram with Raman spectroscopic characterization (and known crystalline solvate structures) enables the identification of the solvate species present. This information greatly aids in understanding the link between solution structure and electrolyte properties.
Genetically Programming Interfaces between Active Materials, Conductive Pathway and Current Collector in Li-Ion Batteries
Authors: Xu Kang , Oh Dahyun , Yi Hyunjung , Qi Jifa , Xu Alice , Snyder James , Belcher Angela
Published: May 2012

In this work we genetically programmed the M13 virus, so that the new clone expressed multifunctional coat protein sequences that selectively bind to designated surfaces and species. Using these new clones, composite network consisting of ironphosphate nanowire (a-FePO4) and single wall carbon nanotubes were self-assembled onto aluminum surfaces. Spectroscopic and electrochemical characterizations confirmed the 3D-structure as well as the electrochemical activity of such composite nanowires.
Prevention of the Micro Cracks Generation in LiNiCoAlO2 Cathode by the Restriction of ΔDOD
Authors: Watanabe Shoichiro , Hosokawa Takashi , Morigaki Ken'ichi , Kinoshita Masahiro , Nakura Kensuke
Published: May 2012

Lithium Nickel-Cobalt-Aluminum oxide cathode material taking out from lithium-ion cell after restricted DOD (Depth of Discharge) range cycle was analyzed by X-ray diffraction (XRD), cross section scanning electron microscope (SEM), transmission electron microscope (TEM) and scanning transmission electron energy-loss spectroscopy (STEM-EELS). Many of the micro cracks were observed in the cathode particles after 0-100% DOD range cycle. On the other hand, that was little confirmed regardless of the operated voltage area when cycled DOD range was restricted. After generation of the micro cracks, the crystal structure at the surface of primary particles which was faced on them was immediately changed to rock salt like structure. The cycle performance under the conditions of restriction of ΔDOD showed superior results of 3000 cycles even at 50°.
Achieving High Capacity by Vanadium Substitution into Li2FeSiO4 for Li-Ion Battery
Authors: Li Yunsong , Cheng Xuan , Zhang Ying
Published: May 2012

The feasibility of vanadium substitution into Li2FeSiO4 to achieve beyond one electron reaction to enhance capacity of cathode material for lithium ion battery is investigated by first-principles calculation based on density functional theory (DFT) within the generalized gradient approximation adding Hubbard-like correlation (GGA+U). The evolutions of the local structures and electronic structures for Li2Fe0.5V0.5SiO4 upon delithiation are analyzed in detail. It is demonstrated that vanadium substitution into Li2FeSiO4 may be thermodynamically possible to achieve more than one lithium ion extractions and, therefore, to significantly enhance the capacity of the Li2FeSiO4 cathode material, and improve electronic conductivity with lower band gap to Li2FeSiO4. Smaller cell parameter changes and more minor local structural distortions with vanadium substitution might be beneficial to stabilize the delithiated phases.
First-Principles Study of Charge Compensation in Olivine Positive
Authors: Asari Yusuke , Suwa Yuji , Hamada Tomoyuki , Dinh Van An , Nara Jun , Ohno Takahisa
Published: May 2012

Mechanisms of charge compensation in olivine-type positive electrodes LiMPO4 (M=Fe and Ni) are theoretically investigated by using the first-principles density functional theory. By introducing the stepwise-elevating Hubbard U, it is shown that the lattice parameters, the bond lengths, the magnetic moments, and the density of states are strongly correlated. According to the site-projected density-of-states, redox center for M=Fe is transition metal regardless of U. In contrast, redox reaction for M=Ni is significantly affected by U. While the redox reaction is Ni2+/Ni3+ at U = 0 eV, the redox center is found to be oxygen at U > 4 eV, where Ni is electrochemically inert because large U makes Ni-3d level deeper in fully-delithiated phase, NiPO4.
C/Li2MnSiO4 as a Composite Cathode Material for Li-Ion Batteries
Authors: Świętosławski Michal , Molenda Marcin , Zaitz Małgorzata M. , Dziembaj Roman
Published: May 2012

This research concerns synthesis of C/Li2MnSiO4 nanocomposite materials and investigation of their structural and electrochemical properties. C/Li2MnSiO4 nanocomposites were produced in a one step process using sol-gel method. Primary carbon coatings of the active material grains were obtained from residual organic gel matrix. Morphology and properties of C/Li2MnSiO4 nanocomposite materials were investigated by thermal analysis (EGA-TGA/DTG/SDTA), X-ray diffraction (XRD), electrical conductivity measurements (EC), N2-BET adsorption measurements and transmission electron microscopy (TEM). The charge/discharge tests in electrochemical Li/Li+/(C/Li2MnSiO4) cells were carried out to characterize electrochemical behavior of the materials. Electrical conductivity measurements reveal very good conductivity of obtained composites (up to 0,36 S•cm-1) at room temperature (RT).
Discharge Performance Dependence on Electrode Thickness for Li4Ti5O12/LiMn2O4 Cells for Application in Wafer-Integrated Microbatteries
Authors: Thunman Mikael , Marquardt Krystan , Hahn Robert , Kober Delf , Goerke Oliver , Schubert Helmut
Published: May 2012

Rechargeable lithium-ion microbatteries are attracting attention for application in self-sufficient microelectronic systems. However, energy densities need to be improved. Introduction of thicker electrodes would increases the energy density. Thus, discharge performance investigations on Li4Ti5O12(s)|LiPF6(sol.)|LiMn2O4(s) pouch-cells containing electrodes with 0.95, 1.90, 2.85, 3.80, and 4.75 mAh cm-2 loading were done. The results showed that for lower current densities (< 13 mA cm-2) the thicker electrodes generate a higher discharged capacity. On the other hand, as the current density rises, the discharged capacity seems to become almost independent of the electrode thickness. This maximum capacity retention might be related to the polarization in the electrolyte and electrodes upon discharging. Based on the Newman model for micro porous electrodes, simulation of the battery discharge characteristics has been done with help of the simulation software COMSOL multiphysics.
Composite Multifunctional Lithium-Ion Batteries
Authors: Mullenax Joshua , Browning Patrick , Huebsch Wade , Gautam Mridul , Sabolsky Edward M.
Published: May 2012

The goal of this work was to design a battery that serves as the structural material as well as the power source for a vessel. The combination of both mechanical and electrochemical aspects within one material defines the component as a multifunctional material, or in this case, a multifunctional battery. The initial work focused on the fabrication of a novel multifunctional lithium ion battery structure, where reinforcement composite fibers were substituted and utilized as active components within the electrodes and separator, enduring cyclic voltage-capacity testing. The second part of this work investigated an approach to modify a conventional lithium ion pouch battery architecture by creating perforations through the cell architecture in order to reduce delamination or wrinkling of the battery during bending loads. The future aim is to fabricate the battery as part of the composite structure instead of a separate piece of the structure.
Li+-Solvation Structure Directs Interphasial Processes on Graphitic Anodes
Authors: Xu Kang , Von Cresce Arthur
Published: May 2012

Using a mass spectrum technique and an "SEI-marker", we successfully established a direct link between Li+-solvation sheath structure and the interphasial processes occurring at graphitic anode.
On the Mechanism of Lithium Insertion into A2Ti6O13 (A = Na, Li)
Authors: Pérez Flores Juan Carlos , Hoelzel Markus , Kuhn Alois , García Alvarado Flaviano
Published: May 2012

A combined structural and electrochemical study of the compounds Na2Ti6O13 and Li2Ti6O13 titanates as anode electrodes for Li-ion batteries is presented. The structural differences between both titanates, where Na and Li atoms are located in an eightfold and [3+1] coordination, respectively, play a crucial role in the electrochemical behavior. Two-dimensional difference Fourier synthesis maps of LixNa2Ti6O13 and LixLi2Ti6O13 using NPD data provide valuable information about the possible reaction mechanism. In the first stages of Li insertion into Na2Ti6O13, Li enters the central tunnel site position (0.5, 0.5, 0.5), whereas the site of truly inserted Li in Li2Ti6O13 could not yet be unequivocally assessed. The different electrochemical behavior of Na2Ti6O13 and Li2Ti6O13 as electrodes in lithium rechargeable batteries is thought to be determined by the structural difference arising from the tunnel alkali metals Na+ and Li+.
Solid State Multinuclear Magnetic Resonance Investigation of Electrolyte Decomposition Products on Lithium-Ion Electrodes
Authors: DeSilva J.H.S.R. , Udinwe Victor , Sideris Paul J. , Smart Marshall C. , Krause F.C. , Hwang C. , Smith K. A. , Greenbaum Steve G.
Published: May 2012

Solid electrolyte interphase (SEI) formation in lithium ion cells prepared with advanced electrolytes is investigated by solid state multinuclear (7Li, 19F, 31P) magnetic resonance (NMR) measurements of electrode materials harvested from cycled cells subjected to an accelerated aging protocol. The electrolyte composition is varied to include the addition of fluorinated carbonates and triphenyl phosphate (TPP, a flame retardant). In addition to species associated with LiPF6 decomposition, cathode NMR spectra are characterized by the presence of compounds originating from the TPP additive. Substantial amounts of LiF are observed in the anodes as well as compounds originating from the fluorinated carbonates.
Status of Carbonate Fuel Cell Materials
Authors: Yuh Chao-Yi , Hilmi Abdelkader , Chen Ling , Franco Adam , Farooque Mohammad
Published: May 2012

The high-temperature carbonate fuel cell is an ultra-clean and high-efficiency power generator. It is operated at ~550-650ºC, an optimum temperature range to facilitate fast fuel-cell reaction kinetics, provide high-quality waste heat, and allow use of commercial available materials. Over eighty power plants manufactured by FCE are operating at customer sites throughout the world. The material selections are founded on many years of focused research. Long-term stack endurance as well as field operation results to date show that the baseline construction materials meet the present 5-year endurance goals. Material durability is well understood and solutions are available to further enhance life and durability.
Hysteresis in the Active Oxidation of SiC
Authors: Jacobson Nathan , Harder Bryan J. , Myers Dwight D.
Published: May 2012

Si and SiC show both passive oxidation behavior where a protective film of SiO2 forms and active oxidation behavior where a volatile suboxide SiO(g) forms. The active-to-passive and passive-to-active oxidation transitions are explored for both Si and SiC. Si shows a dramatic difference between the P(O2) for the two transitions of ~10-4 bar. The active-to-passive transition is controlled by the condition for SiO2/Si equilibrium and the passive-to-active transition is controlled by the decomposition of SiO2. In the case of SiC, the P(O2) for these transitions are much closer. The active-to-passive transition appears to be controlled by the condition for SiO2/SiC equilibrium. The passive-to-active transition appears to be controlled by the interfacial reaction of SiC and SiO2 and subsequent generation of gases at the interface which leads to scale breakdown.
Effect of Surface Preparation on Corrosion Resistance of Electrochemically Deposited Ni-Mo Alloys in the Presence 1-Methyl-Imidazolium Chloride Ionic Liquid
Authors: Allahyarzadeh Mohammad Hossein , Roozbehani Behrooz , Ashrafi Ali , Shadizadeh Seyyed Reza
Published: May 2012

Electrodeposition of Ni-Mo was successfully carried out in the presence of 1-methyl-imidazolium chloride as an additive using ammonia-citrate bath. To investigate the effect of substrate preparation on corrosion resistance; the corrosion resistance of Ni-Mo coatings deposited on mild steel substrate, that was electropolished or mechanically polished, have been compared in 3.5 wt.% NaCl solution using potentiodynamic polarization and electrochemical impedance spectroscopy. The structural properties of Ni-Mo were evaluated using X-ray diffraction and their morphology, microstructure and chemical composition were also investigated using scanning electron microscopy and X-ray energy dispersive spectroscopy. Temperature and pH of the bath have been also changed in order to investigate their effects on corrosion resistance. The results showed that, the Ni-Mo deposited onto electropolished substrates were more resistant to corrosion than on mechanically polished ones; and ionic liquid leads to increase the corrosion resistance of coatings at pH of 8.5, but decreases the corrosion resistance of coatings deposited at pH of 9.5.
Investigation of Ni and Co Deposition into Porous Silicon and the Influence of the Electrochemical Parameters on the Physical Properties
Authors: Rumpf Klemens , Granitzer Petra , Reissner Michael , Poelt Peter , Albu Mihaela
Published: May 2012

Metal-nanostructures are electrochemically deposited within the pores of porous silicon to achieve a hybrid material with specific magnetic properties. For this purpose first the porous silicon template is prepared by wet etching of an n+-type silicon wafer offering pore-diameters between 30 and 100 nm, depending on the anodization parameters. Secondly a ferromagnetic metal is electrodeposited into the pores, whereas the metal structures can be precipitated with various geometries and different spatial distributions depending on an accurate control of the deposition conditions. This method allows to deposit structures as spheres, ellipsoids or wires with a size up to a few micrometers in length whereas the diameter corresponds to the pore-diameter. In the case of Ni the deposition of small particles (2 - 5 nm) succeeded. These nanoparticles are covering the pore-walls and form depending on the packing density tube-like arrangements.
Two-Dimensional Metallo-Semiconductor Networks for Electronic and Photonic Applications
Authors: Tiginyanu Ion , Monaico Eduard , Ursaki Veaceslav
Published: May 2012

Two-dimensional metallo-semiconductor networks have been fabricated by pulsed electrochemical deposition of Pt inside porous GaP membranes with parallel pores possessing diameters in the micrometer and sub-micrometer ranges. The electrochemical parameters were optimized for a uniform metal deposition on the inner surface of the pores. This technology was applied for the fabrication of a variable capacitance device on the basis of Pt/GaP Schottky diodes formed on Pt/GaP interpenetrating networks. The capacitance density variation caused by the change in voltage applied to this device is much higher than that inherent to standard devices. Taking into account the quasi-ordered spatial distribution of pores in the GaP template, one can assume that the produced 2D metallo-semiconductor networks are promising also for specific photonic applications.
Hyaluronic acid regulates normal intestinal and colonic growth in mice
Authors: Riehl Terrence E. , Ee Xueping , Stenson William F.
Published: May 2012

Hyaluronic acid (HA), a component of the extracellular matrix, affects gastrointestinal epithelial proliferation in injury models, but its role in normal growth is unknown. We sought to determine the effects of exogenous HA on intestinal and colonic growth by intraperitoneal injection of HA twice a week into C57BL/6 mice from 3 to 8 wk of age. Similarly, to determine the effects of endogenous HA on intestinal and colonic growth, we administered PEP-1, a peptide that blocks the binding of HA to its receptors, on the same schedule. In mice treated with exogenous HA, villus height and crypt depth in the intestine, crypt depth in the colon, and epithelial proliferation in the intestine and colon were increased. In mice treated with PEP-1, intestinal and colonic length were markedly decreased and crypt depth and villus height in the intestine, crypt depth in the colon, and epithelial proliferation in the intestine and colon were decreased. Administration of HA was associated with increased levels of EGF (intestine) and IGF-I (colon), whereas administration of PEP-1 was associated with decreased levels of IGF-I (intestine) and epiregulin (colon). Exogenous HA increases intestinal and colonic epithelial proliferation, resulting in hyperplasia. Blocking the binding of endogenous HA to its receptors results in decreased intestinal and colonic length and a mucosal picture of hypoplasia, suggesting that endogenous HA contributes to the regulation of normal intestinal and colonic growth.
Steatohepatitis in laboratory opossums exhibiting a high lipemic response to dietary cholesterol and fat
Authors: Chan Jeannie , Sharkey Francis E. , Kushwaha Rampratap S. , VandeBerg Jane F. , VandeBerg John L.
Published: May 2012

Plasma VLDL and LDL cholesterol were markedly elevated (>40-fold) in high-responding opossums, but moderately elevated (6-fold) in low-responding opossums after they had consumed a high-cholesterol and high-fat diet for 24 wk. In both high- and low-responding opossums, plasma triglycerides were slightly elevated, threefold and twofold, respectively. Dietary challenge also induced fatty livers in high responders, but not in low responders. We studied the lipid composition, histopathological features, and gene expression patterns of the fatty livers. Free cholesterol (2-fold), esterified cholesterol (11-fold), and triglycerides (2-fold) were higher in the livers of high responders than those in low responders, whereas free fatty acid levels were similar. The fatty livers of high responders showed extensive lobular disarray by histology. Inflammatory cells and ballooned hepatocytes were also present, as were perisinusoidal fibrosis and ductular proliferation. In contrast, liver histology was normal in low responders. Hepatic gene expression revealed differences associated with the development of steatohepatitis in high responders. The accumulation of hepatic cholesterol was concomitant with upregulation of the HMGCR gene and downregulation of the CYP27A1, ABCG8, and ABCB4 genes. Genes involved in inflammation ( TNF, NFKB1, and COX2) and in oxidative stress ( CYBA and NCF1) were upregulated. Upregulation of the growth factor genes ( PDGF and TGFB1) and collagen genes ( Col1A1, Col3A1, and Col4A1) was consistent with fibrosis. Some of the histological characteristics of the fatty livers of high-responding opossums imitate those in the livers of humans with nonalcoholic steatohepatitis.
Distinct profiles of neuromuscular fatigue during muscle contractions below and above the critical torque in humans
Authors: Burnley Mark , Vanhatalo Anni , Jones Andrew M.
Published: May 2012

Whether the transition in fatigue processes between “low-intensity” and “high-intensity” contractions occurs gradually, as the torque requirements are increased, or whether this transition occurs more suddenly at some identifiable “threshold”, is not known. We hypothesized that the critical torque (CT; the asymptote of the torque-duration relationship) would demarcate distinct profiles of central and peripheral fatigue during intermittent isometric quadriceps contractions (3-s contraction, 2-s rest). Nine healthy men performed seven experimental trials to task failure or for up to 60 min, with maximal voluntary contractions (MVCs) performed at the end of each minute. The first five trials were performed to determine CT [∼35–55% MVC, denoted severe 1 (S1) to severe 5 (S5) in ascending order], while the remaining two trials were performed 10 and 20% below the CT (denoted CT-10% and CT-20%). Dynamometer torque and the electromyogram of the right vastus lateralis were sampled continuously. Peripheral and central fatigue was determined from the fall in potentiated doublet torque and voluntary activation, respectively. Above CT, contractions progressed to task failure in ∼3–18 min, at which point the MVC did not differ from the target torque (S1 target, 88.7 ± 4.3 N·m vs. MVC, 89.3 ± 8.8 N·m, P = 0.94). The potentiated doublet fell significantly in all trials, and voluntary activation was reduced in trials S1–S3, but not trials S4 and S5. Below CT, contractions could be sustained for 60 min on 17 of 18 occasions. Both central and peripheral fatigue developed, but there was a substantial reserve in MVC torque at the end of the task. The rate of global and peripheral fatigue development was four to five times greater during S1 than during CT-10% (change in MVC/change in time S1 vs. CT-10%: −7.2 ± 1.4 vs. −1.5 ± 0.4 N·m·min−1). These results demonstrate that CT represents a critical threshold for neuromuscular fatigue development.
N-acetylcysteine reverses cardiac myocyte dysfunction in HIV-Tat proteinopathy
Authors: Chen Fangping , Lewis William , Hollander John M. , Baseler Walter , Finkel Mitchell S.
Published: May 2012

HIV cardiomyopathy remains highly prevalent among the estimated 33 million HIV-infected individuals worldwide. This is particularly true in developing countries. Potential mechanisms responsible for myocardial dysfunction following HIV infection include direct effects of HIV proteins. We have previously reported that cardiac myocyte-specific expression of HIV-Tat (Tat) results in a murine cardiomyopathy model. We now report that Tat exhibits decreased myocardial ATP [wild type (WT) vs. Tat transgenic (TG), P < 0.01] and myocyte GSH levels (WT vs. TG, P < 0.01), decreased GSH/GSSG ratio (WT vs. TG, P < 0.01), increased H2O2 levels (WT vs. TG, P < 0.05), and increased catalase (TG vs. WT, P < 0.05) and GPX1 (glutathione peroxidase 1) activities (WT vs. TG, P < 0.05), blunted cardiac myocyte positive inotropy (% peak shortening, WT vs. TG, P < 0.01; +d l/d t, WT vs. TG, P < 0.01) and negative inotropy (−d l/d t, WT vs. TG, P < 0.01), and blunted inotropic responses to Ca2+ ( P < 0.01, for each) and shortened anatomical and functional survival in vitro ( P < 0.01). The sulfhydryl donor, N-acetylcysteine (NAC; 10−4 M), completely reversed both the positive and negative inotropic defects in Tat; increased GSH ( P < 0.01) and GSH/GSSG ( P < 0.01); reversed H2O2 level ( P < 0.05) and GPX1 activity ( P < 0.05); and normalized the blunted inotropic response to Ca2+ ( P < 0.01). NAC (10−7) M normalized duration of contractile function from <40 min to >120 min ( P < 0.01), with no effect on GSH and GSH/GSSG. NAC (10−4 M) reverses cardiac myocyte dysfunction and markers of oxidative stress. NAC (10−7 M) enhances myocyte function independent of changes in glutathione. Elucidating the molecular mechanisms involved in the GSH-dependent and GSH-independent salutary effects of NAC should identify novel therapeutic targets for myocardial proteinopathies recently appreciated in human cardiomyopathies.
The 10-20-30 training concept improves performance and health profile in moderately trained runners
Authors: Gunnarsson T. P. , Bangsbo J.
Published: May 2012

The effect of an alteration from regular endurance to interval (10-20-30) training on the health profile, muscular adaptations, maximum oxygen uptake (V̇o2max), and performance of runners was examined. Eighteen moderately trained individuals (6 females and 12 males; V̇o2max: 52.2 ± 1.5 ml·kg−1·min−1) (means ± SE) were divided into a high-intensity training (10-20-30; 3 women and 7 men) and a control (CON; 3 women and 5 men) group. For a 7-wk intervention period the 10-20-30 replaced all training sessions with 10-20-30 training consisting of low-, moderate-, and high-speed running (<30%, <60%, and >90% of maximal intensity) for 30, 20, and 10 s, respectively, in three or four 5-min intervals interspersed by 2 min of recovery, reducing training volume by 54% (14.0 ± 0.9 vs. 30.4 ± 2.3 km/wk) while CON continued the normal training. After the intervention period V̇o2max in 10-20-30 was 4% higher, and performance in a 1,500-m and a 5-km run improved ( P < 0.05) by 21 and 48 s, respectively. In 10-20-30, systolic blood pressure was reduced ( P < 0.05) by 5 ± 2 mmHg, and total and low-density lipoprotein (LDL) cholesterol was lowered ( P < 0.05) by 0.5 ± 0.2 and 0.4 ± 0.1 mmol/l, respectively. No alterations were observed in CON. Muscle membrane proteins and enzyme activity did not change in either of the groups. The present study shows that interval training with short 10-s near-maximal bouts can improve performance and V̇o2max despite a ∼50% reduction in training volume. In addition, the 10-20-30 training regime lowers resting systolic blood pressure and blood cholesterol, suggesting a beneficial effect on the health profile of already trained individuals.
Does increased baseline ventilation heterogeneity following chest wall strapping predispose to airway hyperresponsiveness?
Authors: Chapman David G. , Berend Norbert , Horlyck Karla R. , King Gregory G. , Salome Cheryl M.
Published: May 2012

Baseline ventilation heterogeneity is associated with airway hyperresponsiveness (AHR) in asthma; however, it is unknown whether increased baseline ventilation heterogeneity leads to AHR or both are independent effects of similar disease pathophysiology. Reducing functional residual capacity (FRC) in healthy subjects increases baseline ventilation heterogeneity and airway responsiveness, but the relationship between the two is unclear. The aim was to determine whether an increase in baseline ventilation heterogeneity due to a reduction in FRC correlated with the increase in response to methacholine. In 13 healthy male subjects, ventilation heterogeneity was measured by multiple-breath N2 washout before a cumulative high-dose (0.79–200 μmol) methacholine challenge. On a separate day, the protocol was performed with chest wall strapping (CWS) to reduce FRC. Indexes of ventilation heterogeneity in the convection-dependent (Scond) and diffusion-convection-dependent (Sacin) airways were calculated from the multiple-breath N2 washout. CWS decreased FRC by 15.6 ± 2.7% ( P < 0.0001). CWS increased the percent fall in forced expiratory volume in 1 s during bronchial challenge ( P = 0.006), and the magnitude of this effect was independently determined by the effect of CWS on Sacin and FRC ( radj2 = 0.55, P = 0.02). This suggests that changes in baseline ventilation heterogeneity in healthy subjects are sufficient to increase airway responsiveness, independent of the presence of disease pathology.
Gene Signatures Associated with Mouse Postnatal Hindbrain Neural Stem Cells and Medulloblastoma Cancer Stem Cells Identify Novel Molecular Mediators and Predict Human Medulloblastoma Molecular Classification
Authors: Corno Daniela , Pala Mauro , Cominelli Manuela , Cipelletti Barbara , Leto Ketty , Croci Laura , Barili Valeria , Brandalise Federico , Melzi Raffaella , Di Gregorio Alessandra , Sergi Lucia Sergi , Politi Letterio Salvatore , Piemonti Lorenzo , Bulfone Alessandro , Rossi Paola , Rossi Ferdinando , Consalez Gian Giacomo , Poliani Pietro Luigi , Galli Rossella
Published: May 2012

Medulloblastoma arises from mutations occurring in stem/progenitor cells located in restricted hindbrain territories. Here we report that the mouse postnatal ventricular zone lining the IV ventricle also harbors bona fide stem cells that, remarkably, share the same molecular profile with cerebellar white matter–derived neural stem cells (NSC). To identify novel molecular mediators involved in medulloblastomagenesis, we compared these distinct postnatal hindbrain-derived NSC populations, which are potentially tumor initiating, with murine compound Ptch/p53 mutant medulloblastoma cancer stem cells (CSC) that faithfully phenocopy the different variants of human medulloblastoma in vivo. Transcriptome analysis of both hindbrain NSCs and medulloblastoma CSCs resulted in the generation of well-defined gene signatures, each reminiscent of a specific human medulloblastoma molecular subclass. Most interestingly, medulloblastoma CSCs upregulated developmentally related genes, such as Ebfs, that were shown to be highly expressed in human medulloblastomas and play a pivotal role in experimental medullo-blastomagenesis. These data indicate that gene expression analysis of medulloblastoma CSCs holds great promise not only for understanding functional differences between distinct CSC populations but also for identifying meaningful signatures that might stratify medulloblastoma patients beyond histopathologic staging.

Significance: The functional and molecular comparison between the cell progenitor lineages from which medulloblastoma is thought to arise and medulloblastoma CSCs might lead to the identification of novel, potentially relevant mediators of medulloblastomagenesis. Our findings provide a rationale for the exploitation of mouse CSCs as a valuable preclinical model for human medulloblastoma, both for the definition of CSC-associated gene signatures with predictive mean and for the identification of therapeutically targetable genes. Cancer Discov; 2(6); 554–68. © 2012 AACR.

This article is highlighted in the In This Issue feature, p. 473
A Bioluminescent Transposon Reporter-Trap Identifies Tumor-Specific Microenvironment-Induced Promoters in Salmonella for Conditional Bacterial-Based Tumor Therapy
Authors: Flentie Kelly , Kocher Brandon , Gammon Seth T. , Novack Deborah V. , McKinney Jeffrey S. , Piwnica-Worms David
Published: May 2012

Salmonella specifically localize to malignant tumors in vivo, a trait potentially exploitable as a delivery system for cancer therapeutics. To characterize mechanisms and genetic responses of Salmonella during interaction with living neoplastic cells, we custom-designed a promoterless transposon reporter containing bacterial luciferase. Analysis of a library containing 7,400 independent Salmonella transposon insertion mutants in coculture with melanoma or colon carcinoma cells identified five bacterial genes specifically activated by cancer cells: adiY, yohJ, STM1787, STM1791, and STM1793. Experiments linked acidic pH, a common characteristic of the tumor microenvironment, to a strong, specific, and reversible stimulus for activation of these Salmonella genes in vitro and in vivo. Indeed, a Salmonella reporter strain encoding a luciferase transgene regulated by the STM1787 promoter, which contains a tusp motif, showed tumor-induced bioluminescence in vivo. Furthermore, Salmonella expressing Shiga toxin from the STM1787 promoter provided potent and selective antitumor activity in vitro and in vivo, showing the potential for a conditional bacterial-based tumor-specific therapeutic.

Significance: Salmonella, which often encounter acidic environments during classical host infection, may co-opt evolutionarily conserved pathways for tumor colonization in response to the acidic tumor microenvironment. We identified specific promoter sequences that provide a platform for targeted Salmonella-based tumor therapy in vivo. Cancer Discov; 2(7); 624–37. ©2012 AACR.

Read the Commentary on this article by Hoffman, p. 588.

This article is highlighted in the In This Issue feature, p. 569.
Recurrent Anaphylactic Reactions: An Uncommon Debut of Lymphocytic Hypophysitis
Authors: Bobolea Irina , Guillén Daiana , Barranco Pilar , Alvarez-Escola Cristina , Quirce Santiago
Published: May 2012

We report on a 24-year-old male, with exercise-induced asthma and intermittent abdominal pain since puberty, who suffered from recurrent anaphylactic reactions. He also complained of occasional headaches. After extensive studies he was eventually diagnosed with idiopathic anaphylaxis, once the following diagnoses had been excluded: allergic origin [foods (including ω5-gliadin), latex and drugs], hydatidosis, carcinoid syndrome, systemic mastocytosis, autonomic epilepsy, hereditary angioedema, pheocromocitoma, Meckel diverticle, medullar thyroid carcinoma, leukemia, hyper-IgE and hypereosinophilic syndromes. Given the frequency and severity of the attacks, we started off-label treatment with omalizumab, initially well tolerated. Some days after the second dose the patient started to develop recurrent urticaria. Because of these new symptoms, blood work was repeated, and elevated TSH, decreased T4, positive antithyroid antibodies and decreased cortisol levels with normal ACTH were found. The antiadrenal autoantibodies were negative. The MRI showed a slight thickening of the infundibulum, without pituitary adenoma. Suspecting an autoimmune hypophysitis, we looked for antipituitary antibodies; the result was positive. A clinical picture of recurrent anaphylactic reactions, the result of complicated adrenal crises in an asthmatic patient, was a manifestation of lymphocytic hypophysitis, a rare chronic inflammatory disease of autoimmune etiology. One year after replacement therapy had been started, the patient remained asymptomatic.
Desensitization Effect of Preseasonal Seven-Injection Allergoid Immunotherapy with Olive Pollen on Basophil Activation: The Efficacy of Olive Pollen-Specific Preseasonal Allergoid Immunotherapy on Basophils
Authors: Gokmen Nihal Mete , Ersoy Ramazan , Gulbahar Okan , Ardeniz Omur , Sin Aytul , Unsel Mehmet , Kokuludag Ali
Published: May 2012

Background: It has previously been demonstrated that subcutaneous immunotherapy with allergoids positively affects clinical and immunological parameters even after 7 preseasonal injections. However, its effect on basophil activation remains unclear. We investigated the effect of preseasonal allergoid immunotherapy on basophils and concomitantly assessed its clinical and immunological efficacy in olive pollen-monosensitized patients. Methods: This study enrolled 437 consecutive patients with respiratory allergy and positive skin prick tests (SPTs); 212 (48.5%) patients were sensitized to olive pollen, and 33 (7.5%) patients were sensitized to olive pollen only. Of these patients, 23 received preseasonal immunotherapy with an olive pollen allergoid. The olive pollen-specific basophil activation, the titrated nasal provocation test, the nasal symptom score, and olive pollen-specific IgE, IgG1 and IgG4 levels were evaluated before immunotherapy and 8 months after the end of immunotherapy in the follow-up visit. Results: In comparison to baseline evaluation, 7 preseasonal injections of an allergoid resulted in a significant decrease in the percentage of basophils expressing CD63 (29 vs. 7%, respectively, p < 0.0001) and a significant increase in the titrated nasal provocative dose (1/10 vs. 1/1, respectively, p < 0.01). SPT induration diameters caused by an olive pollen extract decreased (12 mm at baseline vs. 5.5 mm at follow-up, p < 0.005), as did nasal symptom score (7 at baseline vs. 3 at follow-up, p < 0.01). Olive pollen-specific IgE (17.5 vs. 50 kU/l, p < 0.012), IgG1 (0.16 vs. 2.9 µg/ml, p < 0.0001) and IgG4 (0.07 vs. 1.92 µg/ml, p < 0.0001) levels significantly increased. Conclusions: Immunotherapy with 7 preseasonal injections of an olive pollen allergoid decreases olive pollen-specific basophil activation over 8 months, an effect observed in vitro and in vivo.
Biomarkers in Diverticular Diseases of the Colon
Authors: Tursi Antonio
Published: May 2012

Recent data found that diverticular disease (DD) of the colon shows similarities with inflammatory bowel diseases (IBD). In particular, the detection of microscopic inflammation and the clinical response to mesalazine seem to confirm the hypothesis that inflammation may be a key point for the appearance of symptoms and development of complications. In light of this hypothesis, several studies have recently focused their attention on the role of biomarkers in predicting and monitoring the course of the disease. C-reactive protein (CRP), white blood cell count, erythrocyte sedimentation rate, and fecal calprotectin (FC) have therefore been investigated. As in IBD, CRP seems to be the most effective marker of histological and clinical severity of the disease. In particular, CRP below 50 mg/l suggests an acute uncomplicated diverticulitis (AUD), whereas CRP higher than 200 mg/l is a strong indicator of DD complicated by perforation. As in IBD, FC seems to be a noninvasive sensitive marker of DD severity. In particular, FC may show slight increased valued already in symptomatic uncomplicated DD (SUDD) (FC value ≥15 µg/ml seems to be predictive of SUDD). As expected, FC shows higher values in AUD (FC value ≥60 µg/ml seems to be predictive of AUD). Finally, FC seems to be useful also in monitoring the therapeutic response in DD. In fact, FC values decreased significantly in patients responding to therapy, whereas they persisted to increase in patients who failed to obtain remission.
Abnormalities of Neuromuscular Anatomy in Diverticular Disease
Authors: Böttner Martina , Wedel Thilo
Published: May 2012

The pathogenesis of diverticular disease is still poorly understood and considered to be multifactorial. Whereas classical pathogenetic concepts have focused on risk factors including increasing age, low-fiber diet and connective tissue disorders, novel concepts take into account that patients with diverticular disease exhibit disturbed intestinal motility patterns (that may result in functional obstruction and painful sensations) therefore postulating an underlying enteric neuro-/myopathy. Recent studies including quantitative evaluations of the enteric nervous system (ENS) in diverticular disease yielded hypoganglionic conditions of both myenteric and submucosal plexus as well as a nerve tissue remodeling in chronic diverticular disease. The disturbed neuromuscular communication was proven by demonstrating alterations in several enteric neurotransmitter systems, exemplified for the cholinergic, serotonergic, nitrergic system as well as for vasointestinal peptide, galanin and tachykinins. Novel lines of evidence have added the involvement of neurotrophic factors such as glial cell line-derived neurotrophic factor which is supposed to regulate ENS development and maintenance and which is downregulated in patients with diverticular disease. Consistent with the hypothesis of an enteric myopathy, deficits in smooth muscle integrity and composition such as hypertrophy, fibrotic transformation and gene expression deficits could be delineated. Taken together, the structural and functional findings on alterations of the ENS and the enteric musculature in diverticular disease provide evidence to strengthen the hypothesis that an enteric neuro-/myopathy may contribute to the development of colonic diverticula and the generation of symptoms in the course of the disease.
Pathology and Pathogenesis of Diverticular Disease and Patterns of Colonic Mucosal Changes Overlying the Diverticula
Authors: Haboubi N.Y. , Alqudah Mohammad
Published: May 2012

The aim of this article is to review the pathology of diverticular disease and draw attention to the histological changes that affect the wall and the mucosal lining of the sigmoid colon in this common condition. We were the first group to propose a histological classification for sigmoid colitis-associated diverticular disease, and in this paper we are adding another feature to our original observation.
Lifestyle Factors and the Course of Diverticular Disease
Authors: Strate Lisa L.
Published: May 2012

The dramatic increase in the prevalence of diverticular disease after industrialization has led to the belief that diet and lifestyle factors play a significant role in its pathogenesis. Dietary fiber deficiency has received the most attention, although data are limited and conflicting. Two recent cross-sectional studies found no association between fiber intake and diverticulosis, and one found a positive association. However, fiber may improve symptoms associated with uncomplicated diverticulosis and decrease the risk of diverticulitis. Red meat intake may also increase the risk of diverticular symptoms and complications. Contrary to a long-standing belief, a large prospective study found that nuts and corn did not increase the risk of diverticulitis or diverticular bleeding. A number of case-control and prospective studies have found positive associations between obesity and diverticular complications. Central obesity may be particularly important. Vigorous physical activity appears to reduce the risk of diverticulitis and diverticular bleeding. Findings regarding smoking and diverticular complications have been inconsistent, but suggest that smokers are at increased risk for complications, particularly perforation. Alcohol may increase the risk of asymptomatic diverticulosis and diverticulitis. Research is needed to define the role of lifestyle modification in the primary and secondary prevention of diverticulosis and its complications.