bluuebunny/crossref_metadata_2025 huggingface dataset:
Electron Velocity Distribution at a Sheath Edge in the Presence of Secondary Electron Emission From a Metal Surface
Authors: Inai K. , Ohya K. , Kawamura G. , Tomita Y.
Published: May 2010

To estimate the reduction of the electron temperature at a sheath edge in the presence of secondary electron (SE) emission from tungsten (W) and beryllium (Be), we combined the ELECTRAN code, which calculates SE emission from metals, with a kinetic code that used a particle‐in‐cell (PIC) technique. Because the emitted electrons were accelerated toward the bulk plasma by the sheath electric field, the decrease of the effective temperature of electrons at the sheath edge was attributed to the lower sheath electric field. The electron yield for W (high‐Z) was higher than that for Be (low‐Z). SE emission decreased the sheath electric field. Therefore, the effective temperature of electrons for W is lower than that for Be (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dependency of Tritium Retention in Graphite on Temperature Control of Molecular Dynamics
Authors: Ito A. , Ohya K. , Inai K. , Nakamura H.
Published: May 2010

We have investigated the carbon plasma facing material and hydrogen atom interaction by the use of molecular dynamics simulation to clarify chemical erosion processes on divertor plate. The present paper is our first try at elucidation of temperature dependence by the molecular dynamics. Temperature was controlled by using Langevin thermostat method. As a result, the retention of hydrogen atom achieve steady state, and the CH4 was generated, which was not found MD simulations without a temperature control method. About 30 percent of injected hydrogen atoms are retained. CH4 yields has a peak at 600 K, which accords with experimental results. A dominant path of CH4 generation found by the present molecular dynamics simulation is as follows: a CH is detached from eroded surface and then it grows into CH4 adsorbing hydrogen atoms via CH2 and CH3. In addition, we propose the problem that the hydrogen atom retention and CH𝓍 yields depend on the thermal relaxation time in MD simulation using temperature control methods (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Enthalpy/Entropy Compensation in the Melting of Thermotropic Nitrogen‐Containing Chelating Ligands and Their Lanthanide Complexes: Successes and Failures
Authors: Escande Aude , Guénée Laure , Terazzi Emmanuel , Jensen Thomas B. , Nozary Homayoun , Piguet Claude
Published: May 2010

In this short overview dedicated to the thermodynamics of liquid crystalline chelating nitrogen‐containing ligands and their lanthanide complexes (i.e., lanthanidomesogens), we first go through the initial successes obtained with the introduction of the concept of enthalpy/entropy compensation for rationalizing and programming melting and clearing temperatures in thermotropic mesophases. In the second part, the failures encountered during our attempts for switching from a qualitative toward a quantitative interpretation of the melting processes in polycatenar lanthanidomesogens are discussed, together with the delicate correlations established between the thermodynamic parameters of intermolecular cohesion measured in noncoordinating solvents and those operating in pure mesophases.
Mesomerization of S4‐Symmetric Tetrahedral Chelate Complex [In4(L3)4]: First‐Time Monitored by Temperature‐Dependent 1H NMR Spectroscopy
Authors: Saalfrank Rolf W. , Maid Harald , Scheurer Andreas , Puchta Ralph , Bauer Walter
Published: May 2010

VT 1H NMR spectroscopy proved that a non‐dissociative and reversible mesomerization process links the tetranuclear indium(III) complexes meso‐(Δ,Δ,Λ,Λ)(P,P,M,M)‐3 and meso‐(Λ,Λ,Δ,Δ)(M,M,P,P)‐3′. During this process four tandem Bailar twists, resulting in the (Δ)/(Λ) isomerization at the indium centers, and the (P)/(M) inversion of the four coordinating face‐centered, helical ligands (L3)3– are involved. In addition, gas‐phase DFT calculations (B3LYP/LANL2DZp) revealed a C1‐symmetric transition state (+21.9 kcal mol–1) for the mesomerization mechanism which connects 3 and 3′.
Microwave‐Enhanced Rhodium‐Catalyzed [2+2+2] Cycloaddition Reactions To Afford Highly Functionalized Pyridines and Bipyridines
Authors: Garcia Lídia , Pla‐Quintana Anna , Roglans Anna , Parella Teodor
Published: May 2010

Rhodium(I)‐catalyzed [2+2+2] cycloaddition reactions of N‐tosyl‐, carbon‐, and oxygen‐tethered cyanodiynes in a completely intramolecular fashion have been optimized to afford highly functionalized pyridines by conventional and/or microwave heating. Microwaves have been shown to enhance the process by allowing the reaction to be conducted effectively in short reaction times. The methodology has been extended for the synthesis of bipyridines, either by treating a cyanodiyne with an appended pyridine or by conducting a double [2+2+2] cycloaddition reaction on a dicyanotetrayne scaffold. The choice of the solvent in the microwave heating reaction has been shown to be crucial for the success of the process.
A Novel Polycatechol/Ordered Mesoporous Carbon Composite Film Modified Electrode and Its Electrocatalytic Application
Authors: Bai Jing , Bo Xiangjie , Qi Bin , Guo Liping
Published: May 2010

Polycatechol (PCC) was prepared by electropolymerizing catechol (CC) on the surface of an ordered mesoporous carbon (OMC) modified electrode for the first time. Scanning electron microscopy (SEM) and cyclic voltammetry (CV) were used to characterize the structure and electrochemical behaviors of PCC/OMC nanocomposite film. Compared with the bare GC and OMC/GC electrodes, the PCC/OMC/GC electrode exhibits a good electrocatalysis toward the oxidation of NADH at 0.0 V with a high sensitivity (8.7 mA/mM). These make PCC/OMC/GC electrode a promising candidate for stable and efficient electrochemical sensors for the detection of NADH.
Electrocatalytic Performances of Pure and Mixed Hexacyanoferrates of Cu and Pd for the Reduction of Hydrogen Peroxide
Authors: Guadagnini Lorella , Giorgetti Marco , Tarterini Fabrizio , Tonelli Domenica
Published: May 2010

A study on the performances of mixed hexacyanoferrates of Cu and Pd (CuPdHCFs), potentiodynamically grown on glassy carbon surfaces, was carried out. Morphological (SEM‐EDX analysis) and electrochemical characterizations were performed, and the electrocatalytic ability of films with various compositions was tested by chronoamperometry. CuPdHCFs were found to display good electrocatalytic performances, with a maximum sensitivity of 45.3 mA M−1 cm−2 at 0.0 V vs. SCE (depending on the Cu and Pd ratio), against the value of 9.1 mA M−1 cm−2 obtained with pure copper hexacyanoferrate (CuHCF). Additionally, mixed hexacyanoferrates showed a higher pH and operational stability. The key role of Cu in Cu‐based hexacyanoferrates was investigated and highlighted.
Stripping Voltammetry of Trace Metals at Bismuth‐Film Electrodes by Batch‐Injection Analysis
Authors: Economou Anastasios , Voulgaropoulos Anastasios
Published: May 2010

In this work, we explore the utility of batch‐injection analysis (BIA) for the determination of trace metals by stripping voltammetry utilising a bismuth‐film electrode (BiFE). This methodology is characterised by experimental simplicity, low cost, rapidity, versatility and low consumption of solutions. The BIA‐stripping voltammetry combination was applied to the determination of Cd(II), Pb(II), Zn(II) and In(III) by anodic stripping voltammetry (ASV) and of Ni(II), Co(II), U(VI) and Al(III) by adsorptive stripping voltammetry (AdSV). Different strategies using stripping voltammetry in combination with BIA have been investigated, such as the use of polymer‐coated BiFEs and the application of the “medium‐exchange” approach. The analytical usefulness of the methodology has been demonstrated for the analysis of real samples.
Porous Bismuth Film Electrodes for Signal Increase in Anodic Stripping Voltammetry
Authors: Urbanová Veronika , Bartoš Martin , Vytřas Karel , Kuhn Alexander
Published: May 2010

The hard sphere template approach has been used to elaborate highly porous bismuth film electrodes. These electrodes of controlled porosity show an increased internal electroactive area that can be used to enhance significantly the signals obtained for the detection of various metals like lead and cadmium by anodic stripping voltammetry. This leads to improved detection limits opening promising applications in the field of trace analysis.
Voltammetric Determination of Aliphatic Phthalate Esters at a Hanging Mercury Drop Minielectrode and a Meniscus Modified Silver Solid Amalgam Electrode
Authors: Qureshi Munawar Saeed , Fischer Jan , Barek Jiří , Sirajuddin  , Bhanger Muhammad Iqbal
Published: May 2010

A new simple, fast and sensitive differential pulse voltammetric method was developed for the determination of different aliphatic phthalates. Dibutyl phthalate, diethyl phthalate, didecyl phthalate, and diallyl phthalate can be determined in 0.1 M tetramethylammonium bromide in methanol using a hanging mercury drop minielectrode and a meniscus modified silver solid amalgam electrode. Optimum conditions were found including concentration and composition of supporting electrolyte and solvent, scan rate, pulse amplitude, pulse width, etc. Linear calibration curves were obtained for 10−5 and 10−6 M and for hanging mercury drop minielectrode also for 10−7 M.
Depression and hypertension among Chinese nonagenarians and centenarians
Authors: Wen Zhao , Bi‐Rong Dong , Chang‐Quan Huang , Zhen‐Chan Lu , Yuan Zhuang , Hong‐Mei Wu , Yan‐Ling Zhang , Hui Wang , Ping He
Published: May 2010

Purpose

In this study, we explored association between hypertension and depression in the very elderly using a sample ranged in age from 90 to 108 years.

Methods

A cross‐sectional study.

Results

The sample included 687 unrelated Chinese nonagenarians/centenarians (67.4% women, mean age 93.51 years). The mean depression score (measured with brief 23‐item geriatrics depression scale Chinese‐edition (GDS‐CD)) was 8.46 (standard deviation (SD) 3.33 range 0–20). There was no significant difference in depression scores between subjects with and without hypertension and there was also no significant difference in depression prevalence between subjects with and without hypertension. There was no significant difference in prevalence of hypertension between subjects with and without depression and there were also no significant differences in levels of arterial blood pressure (including SBP and DBP). Neither odd ratio (OR) of depression as a function of increased hypertension nor OR of hypertension as a function of increased depression was significant.

Conclusions

In summary, we found that depression was not directly correlated with hypertension among Chinese nonagenarians and centenarians. Copyright © 2010 John Wiley & Sons, Ltd.
Dynamical modelling of concentration–age–discharge in watersheds
Authors: Duffy Christopher J.
Published: May 2010

There is now a wide literature on the use of tracer age and transit time distributions to diagnose transport in environmental systems. Theories have been proposed using idealized tracer age modelling for ocean ventilation, atmospheric circulation, soil, stream and groundwater flow. Most approaches assume a steady flow regime and stationarity in the concentration (tracer) distribution function for age, although recent work shows that this is not a necessary assumption. In this paper, dynamic model for flow, concentration, and age in volume‐averaged and a spatially distributed watershed system are derived in terms of the moments of the underlying distribution function for tracer age, time, and position. Several theoretical and practical issues are presented: (1) The low‐order moments of the age distribution function are sufficient to construct a dynamical system for the mean age and concentration under steady or transient flow conditions. (2) Solutions to the coupled system of equations for flow, concentration and age show that ‘age’ of solutes stored within the watershed or leaving the watershed is a dynamic process which depends on flow variations as well as the solute or tracer dynamics. (3) Intermittency of wetting and drying cycles leads to an apparent increase in the tracer age in proportional to the duration of the ‘dry’ phase. (4) The question of how mobile/immobile flow may affect the age of solutes is examined by including a low permeable, passive store that relaxes the well‐mixed assumption. (5). A spatially distributed advective and dispersive transport solution for age evolution over a simple 1‐D hillslope is developed to demonstrate the age theory for a distributed source of water and tracer, and the solution is shown to have very similar input–output behaviour when compared to the volume‐average model for comparable parameters. Copyright © 2010 John Wiley & Sons, Ltd.
Definitions of homework, types of homework, and ratings of the importance of homework among psychologists with cognitive behavior therapy and psychoanalytic theoretical orientations
Authors: Kazantzis Nikolaos , Dattilio Frank M.
Published: May 2010

A random sample of 827 psychologists were surveyed to assess their definitions of homework, use of homework tasks, and perceived importance of homework. Theoretical orientation distinguished practitioners' responses. Cognitive‐behavioral therapists defined homework as being closer to empirically supported therapy, whereas psychodynamic therapists rated homework as less characteristic of a process that embraces client responsibility and adaptive skills. Cognitive‐behavior therapists did not limit their choices to activity‐based tasks, and psychodynamic therapists reported using behavioral tasks “sometimes.” Monitoring dreams and conscious thought were also used among the entire sample surveyed. Psychodynamic therapists rated homework as “somewhat” or “moderately” important, whereas cognitive‐behavior therapists more often rated homework as “very important.” Data suggest some homework may be common to different psychotherapeutic approaches. Findings are discussed in the context of recent theoretical work on homework in psychotherapy and recommendations for future research. © 2010 Wiley Periodicals, Inc. J Clin Psychol 66:1–16, 2010.
Alcohol dehydrogenase in non‐aqueous media using high‐pressure technologies: reaction set‐up and deactivation determination
Authors: Thorey Paul , Knez Željko , Habulin Maja
Published: May 2010

BACKGROUND: The demand for enantiomerically pure molecules is growing continuously and biocatalysis is a powerful technique for their production. In this work, the catalyst was an enzyme combined with its coenzyme, NADP. High pressure technology, a second clean technology, was applied as well. Dense gases are promising solvents for biocatalysis. They have been investigated extensively as reaction media for lipase‐catalysed reactions, but seldom for reactions, catalysed with alcohol dehydrogenases, as in this work.

RESULT: The production of optically pure R‐1‐phenylethanol from acetophenone was investigated. The NADP‐dependent alcohol dehydrogenase from Lactobacillus brevis (LBADH) was used as a catalyst. The hydrogenation was performed with isopropanol as a co‐substrate in different conditions: dense propane with LBADH and NADP co‐immobilized on glass beads and in the biphasic system water/dense propane. The obtained R‐1‐phenylethanol was enantiopure. The conversions were up to 90%. Deactivation of LBADH was also measured in these media.

CONCLUSION: Protocols were successfully developed for the testing of alcohol dehydrogenase activity in dense gases. Enantioselectivity of LBADH is excellent in those media but it deactivated quickly. An LBADH‐catalysed reaction was performed in a dense gas for the first time. Copyright © 2010 Society of Chemical Industry
Kinetics of toluene and sulfur compounds removal by means of an integrated process involving the coupling of absorption and biodegradation
Authors: Darracq Guillaume , Couvert Annabelle , Couriol Catherine , Amrane Abdeltif , Le Cloirec Pierre
Published: May 2010

BACKGROUND: Scrubbing using an organic solution instead of an aqueous solution could be a useful way to improve the removal of hydrophobic compounds. Absorption of toluene, dimethyldisulfide (DMDS) and dimethylsulfide (DMS) in an organic solution (di‐2‐ethylhexyladipate—DEHA), followed by biodegradation by activated sludge was considered, with particular attention to kinetic aspects. DEHA was selected for its relevance in terms of absorption capacity and absorption velocity of the selected volatile organic compounds (VOCs). After the biodegradation step and owing to its cost, recycling of the VOC‐free solvent should be considered.

RESULTS: Enhancement of VOC mass transfer from the organic to the aqueous phase due to bacterial activity was highlighted and the main driving force was found to be biosurfactant production rather than biodegradation reaction. However, the mass transfer rate between the two phases was shown to be lower than VOC biodegradation rate; hence, significant biodegradation of DMDS and toluene was recorded in a few days during batch experiments, 0.10 and 0.09 mmol respectively. Toluene showed higher biodegradation rates (about 0.05 and 0.10 mg h−1 for DMDS and toluene), leading to higher growth rates. Contrarily, owing to its high volatility, important DMS losses were observed.

CONCLUSION: The relevance of the proposed integrated process was shown for hydrophobic VOC removal, at least for toluene and DMDS. Unfortunately, the absorbent phase was also degraded, proved by detection of by‐products during analyses of the aqueous phase headspace. The comparison of DEHA with other solvents or solid polymers available for multiphase bioreactor applications may be a reliable option to continue this work. Copyright © 2010 Society of Chemical Industry
A facile synthesis of tetrasubstituted 2,3‐dihydrofuran derivatives using poly(ethylene glycol) as soluble support
Authors: Feng Chun , Lu Cuifen , Chen Zuxing , Dong Nianguo , Shi Jiawei , Yang Guichun
Published: May 2010

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A facile synthesis of tetrasubstitude 2,3‐dihydrofurans has been conducted using poly(ethylene glycol) (PEG) as a soluble polymer support. The PEG‐supported pyridinium ylides react with 3‐arylidene‐2,4‐pentanedione in the presence of triethylamine (TEA) via conjugate addition to form PEG‐supported dihydrofuran derivatives, being cleaved by 1% KCN/EtOH to afford trans‐tetrasubstitude‐2,3‐dihydrofurans, varying from good to excellent yields. J. Heterocyclic Chem., (2010).
A straightforward synthesis of pentosidine framework
Authors: Liu Yahua , Zhang Weihan , Sayre Lawrence M.
Published: May 2010

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Pentosidine framework 4‐butyl‐2‐propyl‐4H‐aminoimidazo[4,5‐b]pyridine (2) was synthesized through a five steps reaction sequence. The regiochemistry of 2 was confirmed by an unambiguous synthesis, and the UV absorption and fluorescent properties of 2 were examined. J. Heterocyclic Chem., (2010).
Facile synthesis of 2,6‐diaryl‐4‐secondary aminonicotinonitriles and highly substituted unsymmetrical 2,2′‐bipyridines
Authors: Bhosale Sidhanath V. , Patil Umesh D. , Kalyankar Mohan B. , Nalage Santosh V. , Patil Vijay S. , Desale Kamlesh R.
Published: May 2010

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The ring transformation of 2H‐pyran‐2‐one by N‐aryl amidine in the presence of KOH in DMF at room temperature resulted in a facile synthesis of the 2,6‐diaryl‐4‐secondary aminonicotinonitrile and highly substituted unsymmetrical 2,2′‐bipyridines in moderate yield. J. Heterocyclic Chem., (2010).
Synthesis of α,β‐unsaturated caprolactams starting from heterocyclic imines
Authors: Johannes Katharina , Watzke Martin , Martens Jürgen
Published: May 2010

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New classes of α,β‐unsaturated caprolactams containing variable heteroatoms in δ‐position were synthesized from heterocyclic imines as a starting material. The synthetic route is based on an acid chloride addition followed by a ring‐closing metathesis using a ruthenium catalyst. J. Heterocyclic Chem., (2010).
Sol/Gel Transition of Aqueous Alginate Solutions Induced by Fe2+ Cations
Authors: Hernández Rebeca , Sacristán Javier , Mijangos Carmen
Published: May 2010

Novel information on the gelation mechanism of aqueous alginate solutions in the presence of iron cations is obtained by combining confocal Raman spectroscopy and viscoelastic measurements. The mechanism of gelation of alginate with iron cations is proposed to occur through a combined acid and ionotropic gelation. The low binding ability of iron cations to alginate uronate chains suggests that the formation of iron alginate hydrogels preferentially occurs through an acid gelation. This gives rise to a structure more similar to chemical gels than to physical gels in the sense that they are composed of random aggregates, in contrast to the rod‐like structure exhibited by Ca‐alginate gels.

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Tailoring of Co‐Continuous Polymer Blend Morphology: Joint Action of Nanoclays and Compatibilizers
Authors: Persenaire Olivier , Raquez Jean‐Marie , Bonnaud Leïla , Dubois Philippe
Published: May 2010

The effect of both organoclay (Cloisite® 30B) and compatibilizers (EVA copolymer or MAgPE) on the morphology and mechanical properties is investigated with a special focus on co‐continuous structures. For that purpose, LDPE and PBAT are selected as an inert/reactive polymer pair model. The influence of the nature of the nanoclay/compatibilizer pair on the morphology of the nanocomposite is studied by means of SEM and TEM. Depending on the compatibilizer, it comes out that the organoclay can be selectively located in either the polyolefinic or polyester phase while the interface is invariably stabilized by clay platelets. Interestingly enough, it appears that such a combination (organoclay plus compatibilizer) allows for tailoring the final properties of polymer blends.

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SET‐RAFT Polymerization of Progargyl Methacrylate and a One‐Pot/One‐Step Preparation of Side‐chain Functionalized Polymers via Combination of SET‐RAFT and Click Chemistry
Authors: Zhang Weidong , Zhang Wei , Zhang Zhengbiao , Zhu Jian , Zhu Xiulin
Published: May 2010

A clickable alkyne monomer, PgMA, was successfully polymerized in a well‐controlled manner via single electron transfer initiation and propagation through the radical addition fragmentation chain transfer (SET‐RAFT) method. The living nature of the polymerization was confirmed by the first‐order kinetic plots, the linear relationships between molecular weights and the monomer conversions while keeping relatively narrow $\overline M _{\rm w} /\overline M _{\rm n}$ (≤1.55), and the successful chain‐extension with MMA. The better controllability of SET‐RAFT than other CRP methods is attributed to the less competitive termination in view of the presence of the CTA as well as the Cu(II) that is generated in situ. Moreover, a one‐pot/one‐step technique combining SET‐RAFT and “click chemistry” methods has been successfully employed to prepare the side‐chain functionalized polymers.

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Xanthohumol, a prenylated chalcone from hops, modulates hepatic expression of genes involved in thyroid hormone distribution and metabolism
Authors: Radović Branislav , Hussong Ragna , Gerhäuser Clarissa , Meinl Walter , Frank Norbert , Becker Hans , Köhrle Josef
Published: May 2010

In the present study, we analyzed the influence of xanthohumol (XN) on thyroid hormone (TH) distribution and metabolism in rats. A potent and selective competition of XN for thyroxine (T4) binding to transthyretin (IC50=1 μM at 1.7 nM [125I]T4) was found in human and rat sera in vitro. Female rats treated orally with XN showed increased hepatic expression of T4‐binding globulin and decreased transthyretin and albumin. Thyrotropin levels and hepatic type 1 deiodinase activity were moderately increased. Northern blot analysis revealed diminished expression of liver sulfotransferase (Sult1a1) and uridine‐diphosphate glucuronosyltransferase (Ugt1a1) after XN treatment. The transcript levels of constitutive androstane receptor (CAR), known to be involved in regulation of enzymes metabolizing hormones, drugs and xenobiotics, was lower in rats treated with >10 mg XN/kg body weight per day. Immunoblot analysis indicates reduced amounts of CAR protein. The phenobarbital‐inducible cytochrome P450 mRNA level was decreased in rats treated with >10 mg XN/kg/day, in agreement with reduced CAR protein. Although only moderate changes in TH serum levels were observed, the XN‐dependent altered expression of components involved in TH homeostasis might be important not only for hormone metabolism, but also for hepatic phase I and II elimination of drug metabolites and xenobiotics.
A strictly noninvasive MR setup dedicated to longitudinal studies of mechanical performance, bioenergetics, anatomy, and muscle recruitment in contracting mouse skeletal muscle
Authors: Giannesini Benoît , Vilmen Christophe , Le Fur Yann , Dalmasso Christiane , Cozzone Patrick J. , Bendahan David
Published: May 2010

MR techniques have proven their ability to investigate skeletal muscle function in situ. Their benefit in terms of noninvasiveness is, however, lost in animal research, given that muscle stimulation and force output measurements are usually achieved using invasive surgical procedures, thereby excluding repeated investigations in the same animal. This study describes a new setup allowing strictly noninvasive investigations of mouse gastrocnemius muscle function using 1H‐MRI and 31P‐MR spectroscopy. Its originality is to integrate noninvasive systems for inducing muscle contraction through transcutaneous stimulation and for measuring mechanical performance with a dedicated ergometer. In order to test the setup, muscle function was investigated using a fatiguing stimulation protocol (6 min of repeated isometric contractions at 1.7 Hz). T2‐weighted imaging demonstrated that transcutaneous stimulation mainly activated the gastrocnemius. Moreover, investigations repeated twice with a 7‐day interval between bouts did show a high reproducibility in measurements with regard to changes in isometric force and energy metabolism. In conclusion, this setup enables us for the first time to access mechanical performance, energy metabolism, anatomy, and physiology strictly noninvasively in contracting mouse skeletal muscle. The possibility for implementing longitudinal studies opens up new perspectives in many research areas, including ageing, pharmaceutical research, and gene and cell therapy. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Bone vascularization and trabecular bone formation are mediated by PKBalpha/Akt1 in a gene‐dosage‐dependent manner: In vivo and ex vivo MRI
Authors: Vandoorne Katrien , Magland Jeremy , Plaks Vicki , Sharir Amnon , Zelzer Elazar , Wehrli Felix , Hemmings Brian A. , Harmelin Alon , Neeman Michal
Published: May 2010

PKBalpha/Akt1, a protein kinase, is a major mediator of angiogenic signaling. The purpose of this study was to determine the role of PKBalpha/Akt1 in bone vascularization and development. For that aim, macromolecular dynamic contrast enhanced MRI was applied to examine in vivo vascular changes in long bones of 40‐day‐old growing PKBalpha/Akt1‐deficient, heterozygous, and wild‐type mice. Ex vivo μMRI and μCT were applied to monitor the impact of PKBalpha/Akt1 gene dosage on trabecular bone formation during endochondral bone growth. PKBalpha/Akt1‐deficient mice and, remarkably, also heterozygous mice showed significantly reduced blood volume fraction in the humerus compared to wild‐type mice. Moreover, PKBalpha/Akt1‐deficient mice showed a more severe vascular deficiency with reduced permeability. μCT and μMRI of trabeculae revealed impaired bone formation in both PKBalpha/Akt1‐deficient and heterozygous mice, whereas cortical bone parameters were only reduced in PKBalpha/Akt1‐deficient mice. Reduction of metaphyseal blood vessel invasion, concomitant with aberrant trabeculae and shorter long bones, demonstrates a gene‐dose‐dependent role for PKBalpha/Akt1 in regulation of overall size and endochondral bone growth. MRI proved to provide high sensitivity for in vivo detection of subtle gene dose effects leading to impaired bone vascularity and for uncovering changes in trabecular bone. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Swan neck deformities in rheumatoid arthritis: a qualitative study on the patients' perspectives on hand function problems and finger splints
Authors: van der Giesen F. J. , Nelissen R. G. H. H. , van Lankveld W. J. , Kremers‐Selten C. , Peeters A. J. , Stern E. B. , le Cessie S. , Vliet Vlieland T. P. M.
Published: May 2010

Objective: To identify hand function problems and the reasons for choosing a specific finger splint in patients with rheumatoid arthritis (RA) and swan neck deformities.

Methods: A qualitative study was performed alongside a randomized, controlled cross‐over trial comparing the effectiveness of two types of finger splints (the silver ring splint [SRS] and the prefabricated thermoplastic splint [PTS]) in 50 patients with RA and swan neck deformities. Questions on the patients' main hand function problem and reasons for choosing a specific splint type were performed at baseline and after using each splint. The qualitative analyses included the identification of meaning units and (sub)concepts related to hand function problems and splint preferences.

Results: RA patients with swan neck deformities experience problems with flexion initiation, painful proximal interphalangeal joint hyperextension, grip activities and comprehensive hand function activities. Reasons for preferring or not preferring a specific type of finger splint included: effect, ease of use, appearance, comfort and side effects. Apart from the splint slipping off and a negative attitude towards the appearance of the splint, which appeared to be more frequently mentioned in connection with the SRS, no clear pattern of positive or negative appreciation of either type of splint could be distinguished.

Conclusion: RA patients with swan neck deformities experience a variety of problems, including impairments in functions and limitations in daily activities. With the prescription of finger splints, a substantial number of potentially positive and negative consequences of their use need to be taken into account. Copyright © 2010 John Wiley & Sons, Ltd.
Abnormal liver transaminases and conjugated hyperbilirubinemia at presentation of acute lymphoblastic leukemia
Authors: Segal Idit , Rassekh S. Rod , Bond Mason C. , Senger Christof , Schreiber Richard A.
Published: May 2010

Background

Acute lymphoblastic leukemia (ALL) is the most common malignancy in childhood. While hepatitis is a well‐known complication during the treatment phase of ALL, the association of abnormal liver biochemistries at initial presentation of leukemia is poorly described. The aim of this study is to examine the prevalence and assess the clinical impact of hepatitis at diagnosis in children with ALL.

Procedure

All children diagnosed with ALL at BC Children's Hospital between 2001and 2006 were included. Charts were reviewed and data recorded to a computerized spreadsheet. Descriptive statistical analyses were performed.

Results

One hundred forty‐seven ALL patients were identified. Over one third of patients had abnormal liver transaminase values (AST and/or ALT). Of the patients with abnormal transaminases, (52%) had ALT elevations twice the upper limit of normal. Risk factors for elevated transaminases included a high WBC count at diagnosis, older age, bulky disease, and T‐cell leukemia. Conjugated hyperbilirubinemia was observed in 3.4% of subjects. Of these cases, 60% received steroids prior to induction chemotherapy and all had rapid resolution of their hyperbilirubinemia to normal levels.

Conclusions

Elevated transaminases are common at initial presentation of ALL and are likely due to hepatic injury from leukemic infiltrates. Conjugated hyperbilirubinemia at presentation may require treatment modification and dose reduction. A short course of steroids prior to initiation of induction chemotherapy appears to result in rapid resolution of the hyperbilirubinemia with subsequent ability to provide full dosing of induction chemotherapy. Pediatr Blood Cancer. 2010;55:434–439. © 2010 Wiley‐Liss, Inc.
A spectroscopic approach for structural characterization of polypropylene/clay nanocomposite
Authors: Banerjee Saikat , Joshi Mangala , Ghosh Anup K.
Published: May 2010

This study focuses on the degree of dispersion and structural development of organomodified MMT clay (OMMT) during processing of polypropylene clay nanocomposites using both conventional and nonconventional characterization techniques. PP‐g‐MA and Cloisite 15A were melt blended with three different grades of PP separately in a micro‐twin screw compounder at selected screw speed and temperature. The clay was modified with fluorescent dyes and the adsorbed dye content in the clay gallery was estimated by using UV‐spectrophotometric method. The effects of residence time and molecular weight of the PP matrix on the clay dispersion were studied. The extent of dispersion and exfoliation of the clay in polymer matrix determined from the torque versus time data obtained from microcompounder. It was further supported by XRD, SEM, TEM, and DSC analysis. Offline dielectric and fluorescence spectrophotometric studies were also carried out. Changes in dielectric constant and dielectric loss with both frequency and temperature yielded quantitative information about the extent of clay exfoliation and intercalation in the polymer matrix. It was observed that with an increase in MFI (decrease in molecular weight) and mixing time, the extent of clay dispersion and exfoliation were also improved due to easy diffusion of polymer chains inside clay gallery. POLYM. COMPOS., 31:2007–2016, 2010. © 2010 Society of Plastics Engineers
Synthesis and morphology transformation of amphiphilic diblock polyurethane copolymers in aqueous solution
Authors: Miao Qing , Jin Yong , Dong Yang , Cao Zhifeng , Zhang Biao
Published: May 2010

Amphiphilic block copolymers possess both hydrophobic and hydrophilic properties and can form versatile micellar structures in aqueous solution. The aim of the research presented was to prepare a series of non‐ionic amphiphilic diblock polyurethane copolymers (PUn) based on isophorone diisocyanate, monoallyl‐end‐capped poly(ethylene oxide) and poly(propylene oxide) (PPO), followed by an investigation of their micellization properties and morphology transformation in aqueous solution. The PUn samples were synthesized by condensation polymerization. These polyurethanes exhibit surface tension as low as 33.7–37.0 mN m−1. There is an obvious decrease in critical micelle concentration as the hydrophobic PPO molecular weight increases. According to transmission electron microscopy, the morphology of aggregates of the copolymers can be tuned by varying the concentration in aqueous solution rather than organic solvent. For example, for PU7, large compound micelles are produced instead of vesicles. For PU17, the concentration can be used to control the size and thickness of vesicles. Vesicle size increases from 60 to 500 nm and vesicle thickness from 40 to 60 nm with concentration ranging from 0.003 to 0.03 wt%. The study shows that the copolymers in aqueous solution have excellent surface activities. In addition, they can self‐assemble into large compound micelles or vesicles at certain concentrations. Moreover, the synthesis method described allows one to obtain a desired morphology of aggregates by adjusting the composition of hydrophilic and hydrophobic segments, which provides a novel and simple way to obtain particles on the nanometer scale. Copyright © 2010 Society of Chemical Industry
Nanocomposite coatings via simultaneous organic–inorganic photo‐induced polymerization: synthesis, structural investigation and mechanical characterization
Authors: Belon Cindy , Chemtob Abraham , Croutxé‐Barghorn Céline , Rigolet Séverinne , Schmitt Marjorie , Bistac Sophie , Le Houérou Vincent , Gauthier Christian
Published: May 2010

Hybrid sol–gel films were prepared via a simultaneous organic‐inorganic UV‐curing process using a diaryliodonium salt as a superacid photogenerator. In this single‐step procedure, an epoxy functionalized reactive resin mixed with a variable amount of either of two epoxy trialkoxysilane precursors was UV‐irradiated, causing both the initiation of epoxy ring‐opening copolymerization and the catalysis of trialkoxysilyl sol–gel reactions. The concomitant photo‐induced sol–gel process was found to have a significant effect on the two related propagation mechanisms in competition for the oxirane ring‐opening—the active chain‐end and the activated monomer mechanisms—as proved by a systematic examination of the hybrid material microstructure through 29Si and 13C solid‐state NMR spectroscopy. The effect of the oxo‐silica network generation on the epoxy reaction kinetics was also evaluated using real‐time Fourier transform infrared spectroscopy upon varying the epoxysilane structure and its concentration. Thermal and dynamic mechanical analyses were systematically performed on these hybrids, by studying thoroughly their structure–property interdependence. Other mechanical characterizations through tribological and scratch tests suggested that the present photopolymer–silica hybrid material provides a powerful tool to tailor mechanical property profiles. Copyright © 2010 Society of Chemical Industry
Patient's perceived need and psychological distress and/or quality of life in ambulatory breast cancer patients in Japan
Authors: Akechi Tatsuo , Okuyama Toru , Endo Chiharu , Sagawa Ryuichi , Uchida Megumi , Nakaguchi Tomohiro , Akazawa Terukazu , Yamashita Hiroko , Toyama Tatsuya , Furukawa Toshiaki A.
Published: May 2010

Objective: A needs assessment can be used as a direct index of what patients perceive they need help with. The purposes of this study were to investigate the association between patients' perceived needs and psychological distress and/or quality of life (QOL) and to clarify the characteristics of patients with a high degree of unmet needs.

Methods: Randomly selected ambulatory female patients with breast cancer participated in this study. The patients were asked to complete the Short‐form Supportive Care Needs Survey questionnaire, which covers five domains of need (health system and information, psychological, physical, care and support, and sexuality needs); the Hospital Anxiety and Depression Scale; and the European Organization for Research and Treatment of Cancer QLQ‐C 30.

Results: Complete data were available for 408 patients. The patients' needs were significantly associated with both psychological distress (r=0.63, p<0.001) and QOL (r=−0.52, p<0.001). A multiple regression analysis revealed that employment status (without full‐time /part‐time job), duration since diagnosis (less than 6 months), advanced stage, and a lower performance status were significantly associated with higher total needs. Only sexuality needs were significantly associated with a younger age, while the other domains were significantly associated with duration since diagnosis, advanced stage, and a lower performance status.

Conclusions: Moderate to strong associations exist between patients' needs and psychological distress and/or QOL. The characteristics associated with patients' needs are multi‐factorial, and interventions to respond to patients' needs may be one possible strategy for ameliorating psychological distress and enhancing QOL. Copyright © 2010 John Wiley & Sons, Ltd.
The Meaning‐Making intervention (MMi) appears to increase meaning in life in advanced ovarian cancer: a randomized controlled pilot study
Authors: Henry Melissa , Cohen S. Robin , Lee Virginia , Sauthier Philippe , Provencher Diane , Drouin Pierre , Gauthier Philippe , Gotlieb Walter , Lau Susie , Drummond Nancy , Gilbert Lucy , Stanimir Gerald , Sturgeon Jeremy , Chasen Martin , Mitchell Julie , Huang Lina Nuoxin , Ferland Mira‐Klode , Mayo Nancy
Published: May 2010

Objective: This pilot study aimed to provide supportive evidence for the acceptability and usefulness of the Meaning‐Making intervention (MMi) in patients newly diagnosed with Stage III or IV ovarian cancer, and to provide estimates of parameters needed to design a full‐scale study.

Methods: A randomized controlled trial with 24 patients (12 experimental and 12 control) was conducted. Existential well‐being (primary outcome), overall quality of life, distress, anxiety, depression and self‐efficacy were measured.

Results: Compared to the control group, patients in the experimental group had a better sense of meaning in life at one and three months post‐intervention.

Conclusion: The MMi seems a promising intervention for advanced cancer patients, and a full randomized controlled trial is warranted to further investigate its efficacy. Copyright © 2010 John Wiley & Sons, Ltd.
Glass‐substrate‐based high‐performance ZnO‐TFT by using a Ta2O5 insulator modified by thin SiO2 films
Authors: Zhang L. , Li J. , Zhang X. W. , Yu D. B. , Jiang X. Y. , Zhang Z. L.
Published: May 2010

Thin SiO2 films were used to modify the Ta2O5 insulator (STS) in the ZnO‐TFTs fabricated at room temperature by RF magnetron sputtering. The performance of the device was obviously improved after adding thin SiO2 layers, such as: enhancement of on/off ratio by one order of magnitude, reduction of the subthreshold swing from 0.32 to 0.28 V/dec, increase of the field effect mobility (from 46.2 to 52.4 cm2/V s), as well as reduction of the hysteresis in IDS versus VGS curves and capacitance–voltage characteristics. The capacitance–voltage and C−2 versus voltage characteristics were investigated, from which the trapped charge density at or near the interface between insulator and ZnO layer as well as the carriers concentration of the ZnO film are calculated. The performance enhancements are attributed to the reduce of leakage current, smoother surface morphology, and suppress of charge trapping by using SiO2 films to modify the high‐κ Ta2O5 dielectric.
Structural analysis of nitride‐based LEDs grown on micro‐ and nano‐scale patterned sapphire substrates
Authors: Su Y. K. , Chen J. J. , Lin C. L. , Kao C. C.
Published: May 2010

The structural properties of nitride‐based light‐emitting diodes (LEDs) grown on micro‐ and nano‐scale patterned sapphire substrates (PSS) were discussed in detail. The high resolution X‐ray diffraction (HRXRD) and etch‐pit density (EPD) results reveal that the crystalline quality of the epitaxial GaN film could be effectively improved by using the PSS technique, and depended on the aspect ratio of PSS. The crystalline quality of epitaxial GaN films grown on PSS‐2μm and PSS‐3μm was better than that of the LED grown on NPSS. The electrical characteristics and junction temperature results of the LED grown on micro‐scale PSS were better compared with nano‐scale PSS. But the output power of the LED grown on nano‐scale PSS was larger than that of the LED grown on micro‐scale PSS since the pattern‐size of PSS is related to the capability of light extraction. However, when the spacing of PSS is less than 2 μm, some voids formed at the GaN/sapphire interface may cause the thermal dissipation problem of LEDs. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Exciton localization in Al‐rich AlGaN ternary alloy epitaxial layers
Authors: Murotani Hideaki , Yamada Yoichi , Taguchi Tsunemasa , Kato Ryo , Yokogawa Toshiya
Published: May 2010

Exciton localization in Al‐rich AlGaN ternary alloy epitaxial layers has been studied by means of temperature‐dependent photoluminescence (PL) spectroscopy. Anomalous temperature dependence of the PL peak energy (red‐blue shift) was observed, which enabled us to estimate the localization energy of excitons. The localization energy increased as the 1.2th power of the exciton linewidth. The value of exponent for Al‐rich alloys was smaller than that for Ga‐rich alloys. This indicated that the excitons in Al‐rich alloys were strongly localized compared to that in Ga‐rich alloys. In addition, the exponent value for Al‐rich alloys increased with increasing excitation power density. This increase in the exponent suggested that the exciton population approached the extended states owing to the saturation of localized states by photo‐generated excess excitons. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth of In‐rich and Ga‐rich InGaN alloys by MOCVD and fabrication of InGaN‐based photoelectrodes
Authors: Liu Bin , Luo Wenjun , Zhang Rong , Zou Zhigang , Xie Zili , Li Zhaosheng , Chen Dunjun , Xiu Xiangqian , Han Ping , Zheng Youdou
Published: May 2010

The growth of In‐rich and Ga‐rich InGaN alloys on GaN templates by metal‐organic chemical vapor deposition was investigated. The In content x of InxGa1‐xN is determined by measuring the interplanar spacings of (0002) using high resolution X‐ray diffraction, which agrees with absorption edges obtained by optical transmission measurement. It is found the Ga‐rich InGaN alloys have better crystalline quality, lower background electron concentration and stronger band to band photoluminescence compared than the In‐rich InGaN alloys. The band gap bowing parameter b = 1.31 eV is obtained by fitting the band gap of InxGa1‐xN alloys as function as In content x. The InGaN‐based photoelectrodes were fabricated. The photoelectrodes working in aqueous HBr solution exhibit response to visible light. The incident photon conversion efficiency (IPCE) of an In0.2Ga0.8N photoelectrode achieves up to 9%, which provides one way to utilize solar energy (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Solvation of anionic water‐soluble porphyrins: A computational study
Authors: Guizado Teobaldo R. Cuya , Louro Sonia R. W. , Pascutti Pedro G. , Anteneodo Celia
Published: May 2010

Explicit solvent molecular dynamics simulations of meso‐tetra[4‐sulfonatophenyl] porphyrin (TPPS4−) in water were performed. The relation solute–solvent was examined through the radial distribution function g(r) of water molecules around different groups of the solute. The outcomes of the simulations show that, despite the presence of charged side groups in the particular case of TTPS4−, it displays a global hydrophobic character. Moreover, the hydropathic pattern of the different groups of the solute (central ring and side chains) is also characterized. Additionally, we show that this heterogeneous hydropathicity profile remains basically unaltered by complexing TPPS4− with Fe2+. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Determining the diffusion coefficient of Ni in Cu from a Ni/Cu thin film using linear heating, scanning Auger microscopy and a numerical solution of Fick's second law
Authors: Joubert H. D. , Terblans J. J. , Swart H. C.
Published: May 2010

In previous studies, linear temperature ramping was used to determine diffusion coefficients from bulk‐to‐surface segregation experiments of a low concentration solute. Thin film diffusion studies usually employ a classical heating regime, where a sample's annealing time is taken as the time between insertion and removal from a furnace. The aforementioned study type assumes that the time it takes to heat up a sample after insertion is instantaneous, while the sample cools down instantaneously after removal from the furnace. This assumption is incorrect, as it does not compensate for the various mechanisms that govern heat transfer. In order to eliminate the uncertainty, a linear ramping regime is used and samples were annealed inside an ultra high vacuum (UHV) environment with a programmed linear heating scheme. After each anneal, a depth profile was obtained by simultaneously bombarding the sample with Ar+ ions and monitoring the exposed surface with an electron beam which excites Auger electrons, among others. The depth profiles were normalised and the time scale converted to depth. In order to compare the diffusion profiles obtained from classical annealing studies to the linearly ramped studies, the diffusion coefficient obtained for a classical study of Ni diffusing in Cu was inserted into a numerical solution of Fick's second law, modified to include linear temperature ramping. A diffusion coefficient was also obtained from linearly ramped samples. Comparison of the diffusion profiles calculated with the diffusion coefficients obtained from classical heating and linear heating showed a large discrepancy between the profiles. Copyright © 2010 John Wiley & Sons, Ltd.