bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular Motion in Solid [Sb(CH3)4]X, X = Cl, Br, I, PF6, and BF4. 1H, 19F NMR Second Moment and Crystal Structure
Authors: Burbach Günter , Dou Shi‐Qi , Weiss Alarich
Published: November 2010

The tumbling motion of the tetramethylstibonium cation [Sb(CH3)4]+ has been studied in the ionic compounds [Sb(CH3)4]X, X = Cl, Br, I, PF6, and BF4, by measurement of the second moment of the protons M2(1H) in the temperature range 95 ≧ T/K ≧ 340. — At room temperature the iodide, hexafluorophosphate, and tetrafluoroborate crystallize with hexagonal unit cell. The crystal structure of [Sb(CH3)4]I was determined by single crystal X‐ray diffraction: a = 728.4(3) pm, c = 1037.7(5) pm, space group C46v — P63 mc, Z = 2. — M2 (1H) of [Sb(CH3)4]I shows cation tumbling at T > 320 K. The methyl groups are rotating about their threefold axes in the whole temperature range studied. — In [Sb(CH3)4]PF6 and [Sb(CH3)4]PF4 both, cation and anion are tumbling at T ≧ 259 K and T ≧ 248 K, respectively, as seen by M2(1H) and M2(19F). A jump in the second moments and differential thermal analysis (DTA) of [Sb(CH3)4]BF4 reveals a solid‐solid phase transition with hysteresis (width 28 K). Activation energies for the tumbling motion of the tetramethylstibonium cation have been determined.
Diffusion of Hydrogen in ZrV2Hx
Authors: Schönfeld C. , Schätzler R. , Hempelmann R.
Published: November 2010

The diffusion of hydrogen in the cubic Laves‐phase hydride ZrV2Hx with 0.5 ≦ x ≦ 4.8 has been intensively studied by means of quasielastic neutron scattering using the newly built high resolution backscattering spectrometer at the FRJ‐2 reactor in Jülich. A remarkable feature of this hydride is its phase diagram: by means of differential thermoanalysis we determined the stability range of ordered hydride phases; above 320 K the homogeneous α‐solubility‐phase extends over the whole concentration range. Therefore this system offers the possibility to study the concentration dependence of the H‐diffusion over a wide range not being disturbed by phase transitions. The tracer diffusion coefficient increases with concentration possibly due to the occupation of interstitial sites of different site energy. At low hydrogen concentration we found evidence for a localized motion of hydrogen in the metal host lattice.
The Phase‐Diagram CuI — HgI2
Authors: Nölting J. , Wiegert F. , Puschmann E.
Published: November 2010

Calorimetric measurements have been performed on mixed crystals of couprous and mercury iodide at a wide range of compositions. From these investigations specific heats, transition enthalpies and finally the phase diagram CuI — HgI2were derived. The separating lines of different phase regions were calculated from enthalpies of transition versus composition diagrams. In this way the homogeneous region of the existing compound Cu2HgI4could be determined too.
Thermal Decomposition and Oxidation of HfTe5 Single Crystals
Authors: Saibene S. , Butz T. , Lerf A.
Published: November 2010

We report on time differential perturbed angular correlation measurements of the nuclear quadrupole interaction of 181Hf(β−)181Ta in HfTe5 single crystals during thermal decomposition and oxidation above room temperature. — HfTe5 decomposes under vacuum to HfTe3 + Te and finally to HfTe2 + Te at temperatures between 740–830 K and 820–860 K, respectively. Upon subsequent annealing at about 730 K both products recrystallize to HfTe5. — In air HfTe5 reacts at mild temperatures (380 K) and is completely transformed to a cream‐coloured product after 220 h. Above 730 K this product reacts to HfTe3O8, which is stable up to 1050 K. At higher temperatures this material decomposes irreversibly to HfO2.
Spin Density and Magnetic Susceptibility of Charge‐Transfer Complexes with Chalkogenanthrene Donors
Authors: Gunßer W. , Henning J. H. , Klar G. , Martínez E. Sánchez
Published: November 2010

Spin densities n of CT‐complexes Vn2E2·TCNQ and Vn2E2·DDQ [Vn2E2 = 2,3,7,8‐Tetramethoxychalkogenanthrene (“5,10‐Dichalkogena‐cyclo‐diveratrylene”) with E = S, Se; TCNQ = 7,7,8,8‐Tetracyanoquinodimethane; DDQ = 2,3‐dichloro‐5,6‐dicyanoquinone] are evaluated from EPR measurements in the temperature range of 5–400 K. Three temperature regions with different slopes of ln n vs. 1/T are found. Correlations between donor/acceptor combinations, electrical, magnetic and structural properties are discussed.
Fluid Dynamics in Concurrent Rotary Dryers and Comparison of their Performance with a Modified Dryer
Authors: Silvério B. C. , Façanha J. M. F. , Arruda E. B. , Murata V. V. , Barrozo M. A. S.
Published: November 2010

The present work analyzed aspects of the fluid dynamics of the conventional concurrent dryer equipped with lifting flights and their influence on the performance of a rotary dryer. The drying of granulated fertilizers (GTSP) in a conventional concurrent rotary dryer was experimentally investigated and compared with a modified configuration known as the roto‐aerated dryer. The main feature of this new dryer is the presence of an aerated system consisting of a central pipe (encased in the drum) from which a series of mini‐pipes lead hot air directly to the particle bed, flowing at the bottom (without flights). The results obtained confirm the superior performance of the roto‐aerated dryer due to its more effective gas‐particle contact.
Cellular, Molecular, and Metabolic Basis of Muscle Fatigue
Authors: Fitts Robert H.
Published: November 2010

The sections in this article are:

Definition and Current Theories of Fatigue

Muscle Fiber‐Type Composition

Mechanical Properties

The Isometric Contractile Properties

The Maximal Shortening Speed and Peak Power

The Force‐Frequency Relationship

Excitation‐Contraction Coupling

Sarcolemma and T‐Tubular Membranes

T‐Tubular–Sarcoplasmic Reticulum Junction and Calcium Release

Lactic Acid, Intracellular pH And Fatigue

Muscle Lactate

Hydrogen Ion and Muscle Fatigue

Inorganic Phosphate and Muscle Fatigue

Total Phosphate and the Diprotonated Form

Mechanisms of Phosphate Action

High‐Energy Phosphates and the Free Energy ofATPHydrolysis

ATPand Muscle Fatigue

Blood Glucose and Muscle Glycogen

Hypoglycemia and Performance

Carbohydrate Metabolism and Muscle Fatigue

Ultrastructural Changes and Muscle Fatigue

Muscle Damage and Exercise Intensity

Organelle Susceptibility to Damage

Summary and Conclusions
Thin‐Film Voltammetry of a Lutetium Bisphthalocyanine at Ionic Liquid|Water Interface
Authors: Nassi Achille , Ebelle Christophe Thiery , Njanja Evangeline , Ngameni Emmanuel
Published: November 2010

At room temperature, tetraoctylphosphonium bromide is a viscous ionic liquid, this gel‐like organic phase can be cast over a basal‐plane graphite electrode (BPGE). Cyclic voltammetry at such a modified electrode, in contact with an aqueous solution have revealed one reversible oxidation and five reversible reduction steps for a LuIII bisphthalocyanine dissolved in the ionic liquid film, a proof that the highly reactive reduced species were protected from interaction with water in this highly lipophilic phase. It has also been shown that the redox properties are influenced by the ions in the aqueous phase, a property which has been attributed to ion‐pairing effects; obviously, the ion transfers at the organic|aqueous interface has been ignored. Electrochemistry of Lu(III)[(tBu)4Pc]2 (cyclic voltammetry and square wave voltammetry) under similar conditions shows that the nature and concentration of the anion in the aqueous solution in contact with the ionic liquid film influences the potential of the electrode reaction. This can be attributed to variations of the interfacial potential and also because the organic phase is an anion exchanger. Moreover, SWV experiments suggest that the rate of the overall reaction varies with the nature and concentration of the anion of the aqueous electrolyte, which implies that the ion transfer through the organic|aqueous interface is slower than the electron exchange rate of the molecule at the surface of graphite.
A novel paradigm in greenhouse gas mitigation
Authors: Azad Abdul‐Majeed , McDaniel Eric , Al‐batty Sirhan
Published: November 2010

The ultimate chemical fate of the conventional fossil fuel combustion is always CO2 and H2O, two well‐known greenhouse gases responsible for contributing considerably to the global warming. We propose a radically new concept where CO2 and H2O are converted into carbon monoxide and hydrogen (individually) at one hand and into syngas (if present together; a more likely scenario) under mild experimental conditions. The products then become practical feeds for generating clean electric power via solid oxide fuel cells. Syngas is also an ideal precursor for the manufacturing of scores of valuable organic compounds, including synthetic fuels by Fischer–Tropsch process. Thus, the technique promotes beneficiation rather than sequestration and storage—currently the most widely accepted option for addressing the issue of mitigating the CO2‐related greenhouse gas emission. The process uses either a ferrous metal or its oxide for the target‐specific conversion. In addition to being inexpensive and readily available commodities, the oxide, in particular, happens to be an industrial waste as well; most of it is landfill destined. Furthermore, the two greenhouse gases are reduced into ready‐to‐use fuel precursors, and the solid reactants are transformed into a component from which ceramic magnets (ferrites) could be manufactured. Thus, the concept is innovative because it not only creates valuable clean energy precursors, but it does so while reducing the impact of yet another industrial and ecological pollutant. © 2010 American Institute of Chemical Engineers Environ Prog, 2010
Demand side integration: four potential business cases and an analysis of the 2020 situation
Authors: De Ridder Fjo , Hommelberg Maarten , Peeters Eefje
Published: November 2010

In this study, we explore four different business cases for smart power by means of simulations. The demand and supply are extrapolated to the year 2020 and the influences of photovoltaic installations and demand response are investigated. A district of 300 houses is simulated, where each household consists of three types of intelligent systems: electric devices with a storage capacity like boilers, shiftable loads like washing machines and batteries. Agents, representing devices can trade power on virtual markets, like the PowerMatcher. First, the relation between load flows and smart power is examined. We found, as a rule of thumb, that the variations in load flow decrease proportionally to the fraction controlled power. This might have important consequences for investment policies in power networks. Next, the stability of a cluster is examined. Here it is estimated how long a cluster can remain stable if a constant power flux is imposed. This flexibility can be traded, directly on an imbalance market or through a balance responsible party (BRP). In the next two business cases, the implications for retailers and end‐users are examined for three billing types: a fixed tariff, a two‐tariff structure, and an hourly “real‐time” tariff structure. Compared to the fixed tariff structure, the incentive to use smart devices is small in the double tariff structure. In a real‐time tariff structure incomes increase and risks decrease for retailers, while end‐users have the potential to decrease costs. If we succeed to implement 20% demand response by 2020, our power grid remains able to transport the increased power flows. Copyright © 2010 John Wiley & Sons, Ltd.
Effect of pH Value on Performance of PtRu/C Catalyst Prepared by Microwave‐Assisted Polyol Process for Methanol Electrooxidation
Authors: Chu Y.‐Y. , Wang Z.‐B. , Jiang Z.‐Z. , Gu D.‐M. , Yin G.‐P.
Published: November 2010

PtRu/C catalysts with different mean particle sizes have been synthesised by microwave‐assisted polyol process at various pH values and characterised by transmission electron microscopy (TEM), energy dispersive analysis of X‐ray (EDAX) and X‐ray diffraction (XRD). Their electrochemical performances have been tested by cyclic voltammetry, amperomeric i–t, and CO‐stripping techniques. The effects of pH values on performances of the PtRu/C catalysts have been mainly investigated. It has been found that the particle size, composition and catalytic activity of the PtRu/C catalyst are very sensitive to the pH value of reducing solution, and the PtRu/C catalyst prepared at the pH value of 8 exhibits the better performance for methanol electrooxidation than the other samples. The size of the nanoparticles decreases as the pH value increases from 0.2 to 10 with the largest size of 4.4 nm and the smallest one of 2.1 nm. The two metal elements distribute uniformly in the catalyst and their metal loadings are similar to the theoretical value.
Subquasivarieties of implicative locally‐finite quasivarieties
Authors: Pynko Alexej P.
Published: November 2010

A quasivariety is said to be implicative if it is generated by a class of algebras with equationally‐definable implication of equalities. Implicative finitely‐generated quasivarieties appear naturally within logic, for instance, as equivalent quasivarieties of Gentzen‐style calculi for finitely‐valued propositional logics with equality determinant (cf. [17], [18, Subsection 7.5] and Section A). Furthermore, any discriminator quasivariety is implicative. We prove that, for any implicative locally‐finite quasivariety ℚ and any skeleton S of the class of all finite ℚ‐simple members of ℚ, the image of the first component of a natural Galois connection between the dual poset of subquasivarieties of ℚ and the poset of all sets of finite subsets of S is the closure system of all US‐ideals of the poset 〈S, ⪯〉, where ⪯ is the embeddability relation and US is the up‐set on S constituted by all members of S having a one‐element subalgebra, with closure basis determined by the sets of all principal and non‐empty finitely‐generated up‐sets on S. It is also shown that the first component of the Galois connection under consideration is injective if and only if, for each finite sequence

magnified image

of members of S and any subdirect product 𝔅 of

magnified image

, there is a covering C of the image of

magnified image

such that, for each P ∈ 𝒞, ∏ P is embeddable into 𝔅. This condition (even with one‐element coverings) holds, for instance, when ℚ is discriminator or when ℚ has a set of binary terms satisfying semilattice identities while the direct product of any finite T ⊆ S is generated by corresponding semilattice zeros. We present several examples of quasivarieties which are equivalent to Gentzenstyle calculi for certain well‐known finitely‐valued logics with equality determinant, satisfy the latter sufficient condition of injectivity but are not congruence‐permutable, some of them having non‐simple relatively‐simple algebras. Moreover, we give an example of a quasivariety equivalent to Gentzen‐style calculi for some wellknown finitely‐valued logics with equality determinant, for which the first component of the Galois connection involved is not injective. We also apply our general elaboration to some discriminator quasivarieties, one of which is equivalent to no Gentzen‐style calculus associated with any finitely‐valued logic having an equality determinant while is equivalent to an extension of such a calculus (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Functional MRI characterization of isolated human islet activation
Authors: Leoni Lara , Serai Suraj D. , Magin Richard L. , Roman Brian B.
Published: November 2010

The noninvasive assessment of pancreatic islets would be an invaluable tool in advancing the treatment of type I diabetes and in understanding its pathophysiology. As shown previously in rodents, manganese‐enhanced MRI (MEMRI) can be successfully used to quantify β‐cell function. In this study, we successfully applied this technique to isolated human pancreatic islets in both a static and, more significantly, MRI‐compatible perfusion set‐up. Unlike rodent islets, which produced a significant increase in the signal‐to‐noise ratio (SNR) when treated with 25 µM MnCl2 or less, human islets demonstrated significant manganese uptake when exposed to an extracellular concentration of 50 µM MnCl2. Nonspecific passive manganese uptake was present and quantified in a 15% SNR increase over the control group. However, glucose‐induced manganese uptake caused an SNR increase equal to 45% over nonactivated islets. This corresponds to a statistically significant decrease in the T1 relaxation time from 1501 ms for untreated islets to 1362 ms following passive uptake, and to 861 ms following glucose stimulation. As expected, no manganese cytotoxicity was measured, as shown by normal insulin secretion profiles. These data confirm the viability of MEMRI to assess isolated human islet functionality in vitro, and this technique shows promise for the monitoring of their performance in vivo following transplantation. Copyright © 2010 John Wiley & Sons, Ltd.
A study on fine motor skills of Iranian children with attention deficit/hyper activity disorder aged from 6 to 11 years
Authors: Lavasani Negar Miri , Stagnitti Karen
Published: November 2010

The aim of this study was to compare the fine motor skills of two groups of Iranian children. Of the 55 male Tehranian children aged 6 to 10 years, 29 children were typically developing and 26 were identified as attention deficit hyperactivity disorder (ADHD) using the Diagnostic and Statistical Manual of Mental Disorder. All children were assessed using the Raven Intelligence Test and nine fine motor tasks. There were no significant differences between the groups based on intelligence. In eight of the fine motor tasks, there was a significant difference between the groups. These tasks were cutting, placing dots in a grid pattern without direction, threading beads, drawing a line within 1 and 2 minutes, finger movements and Purdue pegboard. Boys who have been identified as ADHD have poorer fine motor skills compared to typically developing boys of the same age. Children aged 6 to 10 years who have been identified as ADHD will require more attention to their fine motor skill performance to enable greater participation in daily living tasks in Tehran such as writing, fine arts and dressing which require fast and quick hand motor skills. There are still limitations in this area; therefore, research in fine motor skills and ADHD children are recommended for future research. Copyright © 2010 John Wiley & Sons, Ltd.
MRI and DWI: feasibility of DWI and ADC maps in the evaluation of placental changes during gestation
Authors: Manganaro Lucia , Fierro Francesca , Tomei Alessandra , La Barbera Laura , Savelli Sara , Sollazzo Paolo , Eleonora Sergi Maria , Vinci Valeria , Ballesio Laura , Marini Mario
Published: November 2010

Objective

To establish if a correlation exists between apparent diffusion coefficient (ADC) values, obtained by diffusion‐weighted imaging (DWI), and placental aging.

Method

The study is divided into a retrospective phase and a prospective one.

In the first phase, 145 pregnant women underwent fetal magnetic resonance imaging (MRI) for suspected disorders in several organs. We performed DWI (bvalue 0, 200 and 700 s/mm2) in all the fetuses, evaluating the patients in whom the whole placenta was visible.

In the prospective phase, 50 women (52 fetuses) underwent MRI. We performed, in the same patient, two echo‐planar sequences withbvalues of 0, 200 and 700, and 50, 200 and 700 s/mm2, including the whole placenta.

The ADC maps were calculated for all fetuses, divided into three groups based on gestational age (GA): group I: 20–26 weeks' gestation, II: 27–33, III: 34–40.

Results

In the retrospective phase, ADC values had a range from 1 to 2.4 mm2/s, showing a significant correlation between ADC values and GA.

ADC values obtained by DWI withbvalue 0, 200 and 700 s/mm2had a range from 0.8 to 2.5 mm2/s, with an inverse correlation between ADC values and GA, whereas the ADC values withbvalue 50, 200 and 700 s/mm2did not show any statistical correlation (range: 1.5–1.7 mm2/s).

Conclusion

DWI with ADC maps can not be considered markers for placental aging because they are affected by perfusional and circulatory motion. Copyright © 2010 John Wiley & Sons, Ltd.
Is the neutral Knoevenagel reaction initiated by the carbanion formation?
Authors: Yamabe Shinichi , Yamazaki Shoko
Published: November 2010

The title reactions were studied by means of the density functional theory calculations. A base promoted reaction (called here ‘B’) was traced in a model composed of benzaldehyde, malononitrile, and (H2O)11. A neutral model (‘N’) of Ph‐CHO, H2C(CN)2 and (H2O)12 was also examined in line with a reported clean reaction. It was found that the ion pair of HC(CN) and H3O+ is generated at the first step for N. For B, there are five elementary processes, and for N, four ones were obtained. By RB3LY/6‐311 + G** SCRF = PCM//RB3LYP/6‐31(+)G* energy calculations, the rate determining steps for both B and N reactions are the second proton removal, TS5(B) and TS3(N), respectively. In both B and N, the neutral species Ph(HO)HC‐CH(CN)2 is the key intermediate. Copyright © 2010 John Wiley & Sons, Ltd.
Light emission from SrTiO3
Authors: Kanemitsu Yoshihiko , Yamada Yasuhiro
Published: November 2010

We summarized our recent optical studies on perovskite semiconductor SrTiO3 crystals. Photocarrier recombination dynamics of undoped, electron‐doped, and vacancy‐doped SrTiO3 crystals were studied by photoluminescence (PL) and transient absorption (TA) spectroscopy. By high‐density photoexcitation and electron doping, the blue PL is clearly observed in SrTiO3 crystals at room temperature. The PL spectrum and dynamics are sensitive to the photoexcited carrier density and the chemically doped electron density. The PL and TA decay dynamics under high‐density excitation are determined by nonradiative Auger recombination. It is demonstrated that the PL lifetime can be used as a probe for determining spatial profiles of carriers and defects in SrTiO3.
Decay kinetics of the triplet luminescence from self‐trapped excitons in CdMoO4 and ZnWO4
Authors: Itoh Minoru , Kajitani Takushi
Published: November 2010

Decay kinetics of the intrinsic luminescence from the triplet excited state of self‐trapped excitons in CdMoO4 and ZnWO4 has been investigated in a wide temperature range between 7 and 300 K. The measurements are carried out under low‐density excitation with the fourth harmonics (266 nm) of a Nd:YAG laser. The decay curves show two decay components, fast and slow, at T < 40 K in CdMoO4 and at T < 15 K in ZnWO4. At higher temperatures, the decay curves in both materials are well described by single‐exponential functions. A three‐level model consisting of two excited states separated by an energy D and a ground state is applied to explain the temperature dependences of fast and slow decay times. From the fit to the experimental data, we obtain D = 3.7 ± 0.5 meV for CdMoO4 and 2.1 ± 0.3 meV for ZnWO4.
Localization and screening in GdNi alloy films
Authors: Wu N. , LaGraffe D. , Yakovkin I. N. , Dowben P. A.
Published: November 2010

Gd/Ni compounds with different Gd concentration have been investigated with constant initial state spectroscopy (CIS) of photoemission utilizing the light of synchrotron radiation. The photoemission cross‐sections of Gd 5d and 4f states show a strong resonance in CIS spectra at the Gd 5p absorption edge. The screenings of Gd ions by Ni 3d conduction electrons results in a dramatic suppression of the 5p64f75d16s2 to 5p54f75d26s2 resonant enhancement of photoemission valence band intensities. This decrease in the super‐Coster–Kronig photoemission resonant enhancement of the valence band can be related to the hybridized Gd 5d and Ni 3d bands near the Fermi level, consistent with performed first‐principles calculations of local densities of states.
Analysis of thin films and molecular orientation using cluster SIMS
Authors: Green Felicia M. , Seah Martin P. , Gilmore Ian S. , Salter Tara L. , Spencer Steve J.
Published: November 2010

A study of phenylalanine films of different thicknesses from submonolayer to 55 nm on Si wafers has been made using Bin+ and C60+ cluster primary ions in static SIMS. This shows that the effect of film thickness on ion yield is very similar for all primary ions, with an enhanced molecular yield at approximately 1 monolayer attributed to substrate backscattering. The static SIMS ion yields of phenylalanine at different thicknesses are, in principle, the equivalent of a static SIMS depth profile, without the complication of ion beam damage and roughness resulting from sputtering to the relevant thickness. Analyzing thin films of phenylalanine of different thicknesses allows an interpretation of molecular bonding to, and orientation on, the silicon substrate that is confirmed by XPS. The large crater size for cluster ions has interesting effects on the secondary ion intensities of both the overlayer and the substrate for monolayer and submonolayer quantities. This study expands the capability of SIMS for identification of the chemical structure of molecules at surfaces. © Crown copyright 2010.
Self‐Organized Ce1‐xGdxO2‐y Nanowire Networks with Very Fast Coarsening Driven by Attractive Elastic Interactions
Authors: Gibert Marta , Abellán Patricia , Benedetti Alessandro , Puig Teresa , Sandiumenge Felip , García Alberto , Obradors Xavier
Published: November 2010

Assembling arrays of ordered nanowires is a key objective for many of their potential applications. However, a lack of understanding and control of the nanowires’ growth mechanisms limits their thorough development. In this work, an appealing new path towards self‐organized epitaxial nanowire networks produced by high‐throughput solution methods is reported. Two requisites are identified to generate the nanowires: a thermodynamic driving force for an unrestricted elongated equilibrium island shape, and a very fast effective coarsening rate. These requirements are met in anisotropically strained Ce1‐xGdxO2‐y nanowires with the (011) orientation grown on the (001) surface of LaAlO3 substrates. Nanowires with aspect ratios above ≈100 oriented along two mutually orthogonal axes are obtained leading to labyrinthine networks. A very fast effective nanowire growth rate (≈60 nm min−1) for ex‐situ thermally annealed nanostructures derives from simultaneous kinetic processes occurring in a branched network. Ostwald ripening and anisotropic dynamic coalescence, both promoted by strain‐driven attractive nanowire interaction, and rapid recrystallization, enabled by fast atomic diffusion associated with a high concentration of oxygen vacancies, contribute to such an effective growth rate. This bottom‐up approach to self‐organized nanowire growth has a wide potential for many materials and functionalities.
Concise Review: Mesenchymal Stem Cell Treatment of the Complications of Diabetes Mellitus
Authors: Volarevic Vladislav , Arsenijevic Nebojsa , Lukic Miodrag L. , Stojkovic Miodrag
Published: November 2010

Mesenchymal stem cells (MSCs) are multipotent, self-renewing cells that can be found in almost all postnatal organs and tissues. The main functional characteristics of MSCs are their immunomodulatory ability, capacity for self-renewal, and differentiation into mesodermal tissues. The ability of MSCs to differentiate into several cell types, including muscle, brain, vascular, skin, cartilage, and bone cells, makes them attractive as therapeutic agents for a number of diseases including complications of diabetes mellitus. We review here the potential of MSCs as new therapeutic agents in the treatment of diabetic cardiomyopathy, diabetic nephropathy, diabetic polyneuropathy, diabetic retinopathy, and diabetic wounds. Also, in this review we discuss the current limitations for MSCs therapy in humans.
Characterisation of a megavoltage linear accelerator Bremsstrahlung by means of Monte Carlo simulations
Authors: Valente M. , Malano F. , Pérez P. , Castro N. , Carrasco F.
Published: November 2010

This work presents a method for megavoltage X‐ray Bremsstrahlung assessment by means of Monte Carlo (MC) (PENELOPE) simulations. The proposed method provides suitable spectrum characterisation by means of a few parameters, namely the acceleration potential and incident angle of electron beam on the anode. The obtained spectra have been used as incident beam for in‐depth dose distribution determination with the aim of performing further comparisons with experimental data. This comparison procedure has been employed for Bremsstrahlung assessment optimisation. Once the Linac Bremsstrahlung is well established, it may be used as incident beam for further dosimetric purposes, such as spatial dose distribution calculations.

The whole process has been applied for the characterisation of the megavoltage Bremsstrahlung from a typical Linac, namely the 10 MV Varian Clinac 18. The obtained results for in‐depth dose distributions, when compared with experimental measurements, show an overall good agreement, which may suggest the feasibility of the method. Copyright © 2010 John Wiley & Sons, Ltd.
Attitudes of Nigerian women toward the presence of their husband or partner as a support person during labor
Authors: Oboro Victor O. , Oyeniran Ayodeji O. , Akinola Samuel E. , Isawumi Adegboye I.
Published: November 2010

Objective

To assess the attitudes of Nigerian women regarding the presence of a husband/partner during labor.

Methods

Women who were invited to participate in a randomized trial regarding companionship in labor at the Ladoke Akintola University of Technology Teaching Hospital, Osogbo, Nigeria, were interviewed in a qualitative cross‐sectional survey. Demographic characteristics and opinions regarding the presence of a partner/husband as a support person during labor were assessed.

Results

Of the 197 women interviewed, 69 declined all forms of social companionship during labor; of the remaining 128 participants—who did not object to having a social companion—71 declined to have their husband/partner present during labor because of: personal embarrassment (28 [39.4%]); fear of loss of sexual attractiveness (19 [26.8%]); concern for their husband/partner (17 [23.9%]); and lack of privacy (15 [21.1%]). Of the 57 women whose husband/partner accompanied them during labor, 38 (66.7%) said that they would repeat the experience in subsequent labor, and 34 (59.6%) would recommend it. However, 15 (26.3%) expressed dissatisfaction.

Conclusion

The issue of husband/partner companionship during labor is viewed with concern by Nigerian women, who should be allowed to make an informed decision.
Optical characterization of a precipitation event in a moderately hypersaline lake
Authors: Reifel Kristen M. , Swan Brandon K. , Ehrhardt Christopher J. , Jones Burton H.
Published: November 2010

The role of mineral precipitation events in creating large patches of bright green water in the Salton Sea was investigated by comparing in situ inherent optical properties (IOPs) and constituent concentrations within and outside a green water region. While absorption was similar in both regions, scatter and backscatter were ∼2 and 3 times higher in green water, respectively. Ratios of scatter to absorption and backscatter to absorption had nearly identical spectral shapes but much higher magnitudes within green water. CIE chromaticity values were similar between stations, but luminance was 2.4 times greater in green water. Therefore, differences in observed water color were mostly due to increased brightness within green water. Further analyses of IOPs indicated that particles were small at both stations (average diameter ∼0.3 μm), but a larger proportion of particles present in green water were inorganic. Scanning electron microscopy analysis revealed the presence of small (up to 5 μm) particles consistent with gypsum. Because precipitated minerals only increase backscatter and do not by themselves affect water color, simple reflectance ratios will not always detect these events. Therefore, the magnitude of reflectance must be incorporated into analyses of precipitation events.
Effect of top electrode materials on bipolar resistive switching behavior of gallium oxide films
Authors: Gao Xu , Xia Yidong , Ji Jianfeng , Xu Hanni , Su Yi , Li Haitao , Yang Chunjun , Guo Hongxuan , Yin Jiang , Liu Zhiguo
Published: November 2010

Well-developed bipolar resistive switching behaviors have been revealed in Pt/GaOx/ITO stacks without an electroforming process. By substituting platinum with titanium as the top electrode, switching polarity changed from “counter-Figure-8” to “Figure-8.” The modulation of Schottky barrier at the Pt/GaOx interface induced by migration of oxygen vacancies was proposed to explain the switching in Pt/GaOx/ITO stacks, while the switching in Ti/GaOx/ITO stacks was ascribed to the redox reaction at the Ti/GaOx interface. Our experimental result further confirms the migration of oxygen vacancies in the vicinity of the electrode area plays an important role in the resistive switching process.
Modifying infrared scattering effects of single yeast cells with plasmonic metal mesh
Authors: Malone Marvin A. , Prakash Suraj , Heer Joseph M. , Corwin Lloyd D. , Cilwa Katherine E. , Coe James V.
Published: November 2010

The scattering effects in the infrared (IR) spectra of single, isolated bread yeast cells (Saccharomyces cerevisiae) on a ZnSe substrate and in metal microchannels have been probed by Fourier transform infrared imaging microspectroscopy. Absolute extinction [(3.4±0.6)×10−7 cm2 at 3178 cm−1], scattering, and absorption cross sections for a single yeast cell and a vibrational absorption spectrum have been determined by comparing it to the scattering properties of single, isolated, latex microspheres (polystyrene, 5.0 μm in diameter) on ZnSe, which are well modeled by the Mie scattering theory. Single yeast cells were then placed into the holes of the IR plasmonic mesh, i.e., metal films with arrays of subwavelength holes, yielding “scatter-free” IR absorption spectra, which have undistorted vibrational lineshapes and a rising generic IR absorption baseline. Absolute extinction, scattering, and absorption spectral profiles were determined for a single, ellipsoidal yeast cell to characterize the interplay of these effects.
Evaluation of clinical management of gonorrhoea using enhanced surveillance in South East Queensland
Authors: Field Emma , Heel Karen , Palmer Cheryn , Vally Hassan , Beard Frank , McCall Brad
Published: November 2010

Background: Gonorrhoea is the second most common notifiable sexually transmissible infection (STI) in Queensland. Notifications have been increasing since 2002. Enhanced surveillance was undertaken in this study in order to evaluate clinical management and add to understanding of the epidemiology of gonorrhoea and in South East Queensland. Methods: Information on clinical management and an enhanced surveillance form were faxed to clinicians who notified gonorrhoea in the Brisbane Southside Population Health Unit area from 2003 to 2008. Ceftriaxone was recommended for treatment of gonorrhoea cases, as was simultaneous treatment for chlamydia, testing for other STIs and management of sexual contacts. Enhanced surveillance focussed on collecting more detailed epidemiological and clinical management information. Results: A total of 909 enhanced surveillance forms were returned (response rate 72.2%). The use of ceftriaxone increased significantly over the study period from 31.3% in 2003 to 68.4% in 2008 (P < 0.05). However, there remained a considerable proportion of cases that did not receive ceftriaxone (31.6% in 2008). Simultaneous treatment for chlamydia was reported for 70.5% of cases and did not increase over the study period. A high proportion of males were not screened for high risk co-infection such as HIV (49.6%) and syphilis (51.7%). Contact tracing was initiated for 76.5% of cases and did not increase during the study period. Conclusions: Continued education of clinicians on treatment guidelines is needed. Screening of other STIs such as HIV in males with gonorrhoea and increasing contact tracing were identified as aspects of clinical management for future improvement. Overall this study provides useful insights into the clinical management of gonorrhoea in South East Queensland.
NADPH oxidase-mediated reactive oxygen species production activates hypoxia-inducible factor-1 (HIF-1) via the ERK pathway after hyperthermia treatment
Authors: Moon Eui Jung , Sonveaux Pierre , Porporato Paolo E. , Danhier Pierre , Gallez Bernard , Batinic-Haberle Ines , Nien Yu-Chih , Schroeder Thies , Dewhirst Mark W.
Published: November 2010

Hyperthermia (HT) is a strong adjuvant treatment with radiotherapy and chemotherapy because it causes tumor reoxygenation. However, the detailed molecular mechanisms of how HT enhances tumor oxygenation have not been elucidated. Here we report that 1 h of HT activates hypoxia-inducible factor-1 (HIF-1) in tumors and its downstream targets, vascular endothelial growth factor (VEGF) and pyruvate dehydrogenase kinase 1 (PDK1). Consistent with HIF-1 activation and up-regulation of its downstream genes, HT also enhances tumor perfusion/vascularization and decreases oxygen consumption. As a result, tumor hypoxia is reduced after HT, suggesting that these physiological changes contribute to HT-induced tumor reoxygenation. Because HIF-1 is a potent regulator of tumor vascularization and metabolism, our findings suggest that HIF-1 plays a role in HT-induced tumor reoxygenation by transactivating its downstream targets. We demonstrate that NADPH oxidase-mediated reactive oxygen species production, as a mechanism, up-regulates HIF-1 after HT. Furthermore, we determine that this pathway is initiated by increased transcription of NADPH oxidase-1 through the ERK pathway. In conclusion, this study determines that, although HIF-1 is a good therapeutic target, the timing of its inhibition needs to be optimized to achieve the most beneficial outcome when it is combined with other treatments of HT, radiation, and chemotherapy.
Phylogenetic character mapping of proteomic diversity shows high correlation with subspecific phylogenetic diversity in
Trypanosoma cruzi
Authors: Telleria Jenny , Biron David G. , Brizard Jean-Paul , Demettre Edith , Séveno Martial , Barnabé Christian , Ayala Francisco J. , Tibayrenc Michel
Published: November 2010

We performed a phylogenetic character mapping on 26 stocks of
Trypanosoma cruzi
, the parasite responsible for Chagas disease, and 2 stocks of the sister taxon
T. cruzi marinkellei
to test for possible associations between
T. cruzi
–subspecific phylogenetic diversity and levels of protein expression, as examined by proteomic analysis and mass spectrometry. We observed a high level of correlation (
P
< 10
−4
) between genetic distance, as established by multilocus enzyme electrophoresis, and proteomic dissimilarities estimated by proteomic Euclidian distances. Several proteins were found to be specifically associated to
T. cruzi
phylogenetic subdivisions (discrete typing units). This study explores the previously uncharacterized links between infraspecific phylogenetic diversity and gene expression in a human pathogen. It opens the way to searching for new vaccine and drug targets and for identification of specific biomarkers at the subspecific level of pathogens.
Cep152 and Plk4 form a double act
Authors: Short Ben
Published: November 2010

Two centrosomal proteins work together to duplicate centrioles.
Cdc42-mediated MTOC polarization in dendritic cells controls targeted delivery of cytokines at the immune synapse
Authors: Pulecio Julian , Petrovic Jelena , Prete Francesca , Chiaruttini Giulia , Lennon-Dumenil Ana-Maria , Desdouets Chantal , Gasman Stephane , Burrone Oscar R. , Benvenuti Federica
Published: November 2010

The immune synapse (IS) forms as dendritic cells (DCs) and T cells interact in lymph nodes during initiation of adaptive immunity. Factors that contribute to the formation and maintenance of IS stability and function have been mostly studied in T cells, whereas little is known about events occurring during synapse formation in DCs. Here, we show that DCs activated by Toll-like receptor (TLR) agonists reorient the microtubule-organizing center (MTOC) toward the interacting T cell during antigen-specific synapse formation through a mechanism that depends on the Rho GTPase Cdc42. IL-12, a pivotal cytokine produced by DCs, is found enriched around the MTOC at early time points after TLR ligation and is dragged to the DC–T cell interface in antigen-specific synapses. Synaptic delivery of IL-12 induces activation of pSTAT4 and IFN-γ neosynthesis in CD8+ naive T cells engaged in antigen-specific conjugates and promotes the survival of antigen-primed T cells. We propose that DC polarization increases the local concentration of proinflammatory mediators at the IS and that this represents a new mechanism by which T cell priming is controlled.
Do ribosomopathies explain some cases of common variable immunodeficiency?
Authors: Khan S , Pereira J , Darbyshire P J , Holding S , Doré P C , Sewell W A C , Huissoon A
Published: November 2010

The considerable clinical heterogeneity of patients with common variable immunodeficiency disorders (CVID) shares some similarity with bone-marrow failure disorders such as Diamond–Blackfan anaemia (DBA) and Shwachman–Diamond syndrome (SDS), now recognized as defects in ribosome biogenesis or ribosomopathies. The recognition of a patient with DBA who subsequently developed CVID lends support to our previous finding of a heterozygous mutation in the SBDS gene of SBDS in another CVID patient, suggesting that ribosome biogenesis defects are responsible for a subset of CVID. Genetic defects in the ribosomal translational machinery responsible for various bone marrow failure syndromes are recognized readily when they manifest in children, but diagnosing these in adults presenting with complex phenotypes and hypogammaglobulinaemia can be a challenge. In this perspective paper, we discuss our clinical experience in CVID patients with ribosomopathies, and review the immunological abnormalities in other conditions associated with ribosomal dysfunction. With genetic testing available for various bone marrow failure syndromes, our hypothesis that ribosomal abnormalities may be present in patients with CVID could be proved in future studies by testing for mutations in specific ribosomal genes. New knowledge might then be translated into novel therapeutic strategies for patients in this group of immunodeficiency disorders.
Functional genomics of the evolution of increased resistance to parasitism in Drosophila
Authors: WERTHEIM BREGJE , KRAAIJEVELD ALEX R. , HOPKINS MEIRION G. , WALTHER BOER MARK , GODFRAY H. CHARLES J.
Published: November 2010

Individual hosts normally respond to parasite attack by launching an acute immune response (a phenotypic plastic response), while host populations can respond in the longer term by evolving higher level of defence against parasites. Little is known about the genetics of the evolved response: the identity and number of genes involved and whether it involves a pre‐activation of the regulatory systems governing the plastic response. We explored these questions by surveying transcriptional changes in a Drosophila melanogaster strain artificially selected for resistance against the hymenopteran endoparasitoid Asobara tabida. Using micro‐arrays, we profiled gene expression at seven time points during development (from the egg to the second instar larva) and found a large number of genes (almost 900) with altered expression levels. Bioinformatic analysis showed that some were involved in immunity or defence‐associated functions but many were not. Previously, we had defined a set of genes whose level of expression changed after parasitoid attack and a comparison with the present set showed a significant though comparatively small overlap. This suggests that the evolutionary response to parasitism is not a simple pre‐activation of the plastic, acute response. We also found overlap in the genes involved in the evolutionary response to parasitism and to other biotic and abiotic stressors, perhaps suggesting a ‘module’ of genes involved in a generalized stress response as has been found in other organisms.
Inhibition of the migrating motor complex by duodenal drainage in man
Authors: NILSSON I. , SVENBERG T. , HEDENBORG G. , LÖRDAL M. , HELLSTRÖM P. M.
Published: November 2010

Abstract The effect of varying bile acid output on fasting small intestinal motility was investigated in healthy male volunteers. Biliary output was manipulated by jejunal infusion of isotonic mannitol, which resulted in increased output, and by prolonged drainage of duodenal contents, which resulted in decreased output. Intestinal motility was measured by manometric recordings performed at four levels in the proximal small intestine. A marker dilution technique was used to measure pancreatico‐biliary output. There were three experimental groups: duodenal drainage, non‐drainage and control. Both duodenal drainage and non‐drainage groups underwent jejunal saline infusion, followed by mannitol infusion. The control group did not receive drainage or infusions. In the drainage group, 0.41 (0.13‐0.68) activity fronts of the migrating motor complex (MMC) per hour were recorded during saline infusion, but only 0.06 (0‐0.19) activity fronts per hour were observed during mannitol infusion. In the nondrainage group, 0.71 (0.61‐0.81) activity fronts per hour were observed during saline infusion and 0.50 (0.18‐0.82) activity fronts per hour were recorded during mannitol infusion. In the control group, 0.58 (0.33–0.84) activity fronts per hour were recorded during the first 4‐h session and 0.58 (0.45‐0.71) activity fronts per hour during the second session. There was no difference between the number of activity fronts per hour observed in the control group and those observed in the saline infusion of the drainage group. In contrast, there was a significant decrease in the number of activity fronts per hour in the drainage group during mannitol infusion, compared to both non‐drainage group during mannitol infusion (P < 0.01) and controls (P < 0.05). In conclusion, decreased biliary output caused by duodenal drainage in combination with mannitol infusion is associated with inhibition of the cyclic activity of MMC in the proximal small intestine in man.
Effects of nutrient solutions on concentration analysis of non‐absorbable dilution markers – implications for studies of gastric emptying
Authors: RÜHL A. , LÜBKE H. , WIENBECK M.
Published: November 2010

Abstract Gastrointestinal luminal contents may interfere with concentration analysis of non‐absorbable dyes. However, non‐absorbable markers are broadly used for studies of gastric emptying rates of nutrient solutions. This prompted us to evaluate the properties of non‐absorbable markers to mark such nutrient solutions. In vitro concentrations of polyethylene glycol phenol red, dextran blue, two anthroquinone dyes and inulin were determined spectrophotometrically in the presence or absence of a formula diet, single compounds of the diet or an oligo‐peptide diet, and the reproducibility and validity of the analyses were evaluated. The presence of the formula diet or the oligopeptide diet seriously impaired the analyses of marker concentrations, whereas single nutrient compounds did not uniformly interfere. The analysis of polyethylene glycol and phenol red concentrations was impaired by proteins, while the analysis of inulin concentration was impaired by carbohydrates. Dextran blue and the anthroquinones were completely eliminated by protein‐precipitation procedures. In conclusion, phenol red and polyethylene glycol should only be used as marker substances for protein‐free meals or nutrient solutions, while inulin should not be used with meals or nutrient solutions containing carbohydrates. Marker dilution techniques cannot be recommended for measurements of gastric emptying rates of complete meals.