bluuebunny/crossref_metadata_2025 huggingface dataset:
McKusick‐Kaufman syndrome: The difficulty of establishing a prenatal diagnosis of an uncommon disorder
Authors: Slavin Thomas P. , McCandless Shawn E. , Lazebnik Noam
Published: January 2010

Prenatal evaluation of abdominal cystic masses can be complex and challenging. We report the case of a fetus with a large cystic abdominal mass and discuss how the differential diagnosis was narrowed to include McKusick‐Kaufman syndrome (MKS). MKS is characterized by the triad of postaxial polydactyly, congenital heart disease, hydrometrocolpos, and genital malformations in males. Rare conditions such as MKS are difficult to diagnose prenatally and require postnatal phenotyping and molecular studies before a definitive diagnosis can be established. © 2010 Wiley Periodicals, Inc. J Clin Ultrasound 2010
Is neonatal risk from vasa previa preventable? The 20‐year experience from a single medical center
Authors: Smorgick Noam , Tovbin Yosef , Ushakov Fred , Vaknin Zvi , Barzilay Bernard , Herman Arie , Maymon Ron
Published: January 2010

Background.

Vasa previa is a rare condition associated with neonatal morbidity and mortality that may be diagnosed prenatally using transvaginal sonography. The aim of this study was to assess the prenatal detection of vasa previa and its subsequent impact on neonatal outcomes in two 10‐year periods (1988–1997 versus 1998–2007).

Method.

Retrospective review of all cases of vasa previa. Data on obstetrical history, modes of conception, sonographic scans, delivery mode, and neonatal outcome were retrieved and recorded.

Result.

There were 19 pregnancies (21 neonates) with confirmed vasa previa (overall incidence of 1.7/10,000 deliveries). Vasa previa were diagnosed prenatally in 10 (52.6%) cases. In cases without prenatal diagnosis, there was a higher proportion of neonates with 1′ Apgar score ≤5 and cord blood pH <7 compared with cases diagnosed prenatally (66.7% versus 10%, p ≤ 0.05, and 33.3% versus 0%, p < 0.05, respectively). The prenatal detection rate of vasa previa increased from 25 to 60% between the 2 time periods (p > 0.05), whereas perinatal mortality and 1′ Apgar scores ≤5 decreased from 25 to 0% and from 50 to 33.3% (p > 0.05).

Conclusion.

Prenatal sonographic screening using targeted scans for vasa previa in women at risk or as part of routine mid‐gestation scanning may significantly impact its obstetric manifestations. © 2010 Wiley Periodicals, Inc. J Clin Ultrasound, 2010
On the purity of 2‐[ortho‐anilinyl]‐1,3‐benzoxazole derived from 2H‐3,1‐benzoxazine‐2,4(1H)dione (isatoic anhydride) [1,2]
Authors: Button Karen M. , Gossage Robert A. , Jenkins Hilary A. , Mahdi Tayseer , Resanović Sanja
Published: January 2010

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The Lewis acid catalyzed synthesis and chromatographic purification of isatoic anhydride‐derived 2‐(2′‐anilinyl)‐1,3‐benzoxazole (2) can result in the co‐isolation of 2 and a light pink colored impurity (<5%). This latter species has been identified (NMR, single crystal X‐ray diffraction, mp) as 2′‐hydroxy‐2‐aminobenzanilide (3), which represents a predictable intermediate in the formation of 2. Compound 3 crystallizes in an orthorhombic crystal system of space group P212121 with four molecules in the unit cell (α = β = γ = 90°; a = 6.715 (2) Å, b = 12.100 (4) Å, c = 13.321 (4) Å; V = 1082.2 (6) Å3). Pure 2 is characterized as a colorless, high‐melting solid; unlike the dark colored oil that is isolated if 2 contains traces of 3. J. Heterocyclic Chem., (2010).
D‐Serine metabolism in C6 glioma cells: Involvement of alanine‐serine‐cysteine transporter (ASCT2) and serine racemase (SRR) but not D‐amino acid oxidase (DAO)
Authors: Sikka Pilleriin , Walker Rosie , Cockayne Rebecca , Wood Matthew J.A. , Harrison Paul J. , Burnet Philip W.J.
Published: January 2010

D‐serine is an endogenous N‐methyl‐D‐aspartate (NMDA) receptor coagonist. It is synthesized from L‐serine by serine racemase (SRR), but many aspects of its metabolism remain unclear, especially in the forebrain, which lacks active D‐amino acid oxidase (DAO), the major D‐serine degradative enzyme. Candidate mechanisms include SRR operating in α,β‐eliminase mode (converting D‐serine to pyruvate) and regulation by serine transport, in which the alanine‐serine‐cysteine transporter ASCT2 is implicated. Here we report studies in C6 glioma cells, which “simulate” the forebrain, in that the cells express SRR and ASCT2 but lack DAO activity. We measured D‐serine, ASCT2, SRR, and DAO expression and DAO activity in two situations: after incubation of cells for 48 hr with serine isomers and after increased or decreased SRR expression by transfection and RNA interference, respectively. Incubation with serine enantiomers decreased [3H]D‐serine uptake and ASCT2 mRNA and increased SRR immunoreactivity but did not alter DAO immunoreactivity, and DAO activity remained undetectable. SRR overexpression increased D‐serine and pyruvate and decreased [3H]D‐serine uptake and ASCT2 mRNA but did not affect DAO. SRR knockdown did not alter any of the parameters. Our data suggest that D‐serine transport mediated by ASCT2 contributes prominently to D‐serine homeostasis when DAO activity is absent. The factors regulating D‐serine are important for understanding normal NMDA receptor function and because D‐serine, along with DAO and SRR, is implicated in the pathogenesis and treatment of schizophrenia. © 2010 Wiley‐Liss, Inc.
Serum ceruloplasmin and copper are early biomarkers for traumatic brain injury‐associated elevated intracranial pressure
Authors: Dash Pramod K. , Redell John B. , Hergenroeder Georgene , Zhao Jing , Clifton Guy L. , Moore Anthony
Published: January 2010

High intracranial pressure (ICP) is a prominent secondary pathology after traumatic brain injury (TBI) and is a major contributor to morbidity and mortality. Currently, there are no clinically proven methods for predicting which TBI patients will develop high ICP. In the present study, we examined whether the serum levels of the copper‐binding protein ceruloplasmin are differentially altered in patients with elevated ICP (≥25 mmHg) vs. those whose ICP remained below 20 mmHg throughout the study period. Consistent with its role as an acute‐phase reactant, we found that ceruloplasmin levels were significantly increased by 3 days post‐TBI compared with healthy volunteers. However, prior to this delayed increase, ceruloplasmin levels during the first 24 hr following injury were found to be significantly reduced in patients who subsequently developed high ICP. This decrease was found to have prognostic accuracy in delineating TBI patients based on their ICP status (cutoff of 140 μg/ml; sensitivity: 87%, specificity: 73%), Likewise, low total serum copper (below 1.32 μg/ml) was also found to be predictive of high ICP (sensitivity 86%, specificity 73%). These results suggest that initial serum ceruloplasmin/copper levels may have diagnostic value in predicting patients at risk for developing high intracranial pressure. © 2010 Wiley‐Liss, Inc.
Effects of detrital carbonate on stable oxygen and carbon isotope data from varved sediments of the interglacial Piànico palaeolake (Southern Alps, Italy)
Authors: Mangili Clara , Brauer Achim , Plessen Birgit , Dulski Peter , Moscariello Andrea , Naumann Rudolf
Published: January 2010

Contamination with detrital matter is a well‐known bias in δ18O records from lake carbonates but quantitative information of this effect is yet lacking. Therefore, we developed a new methodological approach combining isotope analyses with microfacies, X‐ray diffraction and micro‐X‐ray fluorescence data and applied this in a case study for the Piànico interglacial lake record in order to provide a quantitative estimate of the effect of detrital carbonate on stable δ18O and δ13C data. The Piànico record contains a long series of distinct and well‐preserved calcite varves and is correlated to Marine Isotope Stage 11. Intercalated in the varve sequence are detrital layers triggered by surface erosion events. These detrital layers are mainly composed of dolomite, thus reflecting the mineralogical signature of the catchment. Microfacies analyses of a 9350 varve year interval allows the identification of detrital layers down to sub‐millimetre scale and a precise selection of three different types of samples for isotope analyses: (1) pure endogenic calcite varves (five varves per sample) without detrital contamination; (2) individual detrital layers; and (3) ‘mixed’ samples including five calcite varves and up to four thin detrital layers. Detrital samples show the isotopic signature of the catchment dolomite and are up to 5.7‰ enriched in δ18O values with respect to endogenic calcite samples. In mixed samples, the degree of isotopic enrichment is directly related to the amount of detrital contamination; δ18O of bulk carbonates is significantly biased when the detrital component amounts to more than 5% of the sample. It is also shown that samples containing detrital material have an influence on the calculation of the covariance between δ13C and δ18O. Covariance is high (r = 0.76) when the correlation coefficient is calculated on the base of all samples, but absent (r = −0.43) when samples containing detrital dolomite are excluded. It has been demonstrated that microfacies analysis is a quick tool to avoid or reduce detrital contamination in bulk carbonate samples during sample selection. Copyright © 2009 John Wiley & Sons, Ltd.
Simultaneous HPLC determination of 14 tricyclic antidepressants and metabolites in human plasma
Authors: Mercolini Laura , Mandrioli Roberto , Finizio Giulia , Boncompagni Giancarlo , Raggi Maria Augusta
Published: January 2010

A HPLC method has been developed for the simultaneous determination of seven tricyclic antidepressants (TCAs) and seven metabolites in human plasma. The analyte separation was obtained using a C8 reversed phase column and a mobile phase composed of 68% aqueous phosphate buffer at pH 3.0 and 32% ACN. The UV detector was set at 220 nm and loxapine was used as the internal standard. A careful pre‐treatment procedure for plasma samples was developed, using SPE on C2 cartridges, which gives satisfactory extraction yields (>80%) and good sample purification. The LOQs were always lower than 9.1 ng/mL and the LODs always lower than 3.1 ng/mL for all analytes. The method was successfully applied to plasma samples from depressed patients undergoing therapy with one or more TCA drugs. Precision data (RSD <8.1%), as well as accuracy results (recovery >80%), were satisfactory and no interference from other drugs was found. Hence the method seems to be suitable for the therapeutic drug monitoring of patients treated with TCAs under monotherapy or polypharmacy regimens.
Visible light initiated polymerization of styrenic monolithic stationary phases using 470 nm light emitting diode arrays
Authors: Walsh Zarah , Levkin Pavel A. , Jain Vijay , Paull Brett , Svec Frantisek , Macka Mirek
Published: January 2010

Poly(styrene‐co‐divinylbenzene) monolithic stationary phases have been synthesized for the first time by photoinitiated polymerization. An initiator composed of (+)‐(S)‐camphorquinone/ethyl‐4‐dimethylaminobenzoate/N‐methoxy‐4‐phenylpyridinium tetrafluoroborate was activated using a 470 nm light emitting diode array as the light source. Spatially controlled polymerization of styrenic monoliths has been achieved within specific sections of a 100 μm id polytetrafluoroethylene‐coated fused‐silica capillary using simple photo masking. The sharpness of the edges was confirmed by optical microscopy, while SEM was used to verify a typical porous, globular morphology. Flow resistance data were used to assess the permeability of the monoliths and they were found to have good flow through properties with a flow resistance of 0.725 MPa/cm at 1 μL/min (water, 20°C). Conductivity profiling along the length of the capillary was used to assess their lateral homogeneity. Monoliths which were axially rotated during polymerization were found to be homogeneous along the whole length of the capillary. The monolithic stationary phases were applied to the RP gradient separation of a mixture of proteins. Column fabrication showed excellent reproducibility with the retention factor (k) having a RSD value of 2.6% for the batch and less than 1.73% on individual columns.
Photodynamic therapy of cottontail rabbit papillomavirus‐induced papillomas in a severe combined immunodeficient mouse xenograft system
Authors: Lee Richard G. , Vecchiotti Mark A. , Heaphy John , Panneerselvam Ashok , Schluchter Mark D. , Oleinick Nancy L. , Lavertu Pierre , Alagramam Kumar N. , Arnold James E. , Sprecher Robert C.
Published: January 2010

Objectives/Hypothesis:

To evaluate the efficacy of photodynamic therapy (PDT) with the phthalocyanine photosensitizer Pc 4 for treating an animal model of recurrent respiratory papillomatosis (RRP).

Methods:

Rabbit skin was grafted onto the dorsum of severe combined immunodeficient mice, two xenografts per animal. After the graft healed, it was inoculated with cottontail rabbit papillomavirus (CRPV). When papillomas developed, Pc 4 (0.6 or 1.0 mg/kg) was administered systemically, and 48 hours later, one papilloma of the two on each animal was exposed to 675‐nm photoactivating light at either 100 or 150 J/cm2. In addition to the contralateral tumors, which received Pc 4 but no light, other controls included animals receiving light only or neither agent. Response was assessed by measuring papilloma size with a caliper. Some papillomas and residual skin were harvested for histological assessment.

Results:

For the lower‐dose PDT regimens, papilloma growth rates were not significantly different from the controls. In contrast, 13 of 15 papillomas receiving the higher Pc 4 dose (1.0 mg/kg) and the higher light fluence (150 J/cm2) regressed completely and did not regrow within the observation period of up to 79 days. The response of these papillomas was significantly different from the controls (P < .001). Histological analysis confirmed the absence of residual tumor following complete response and replacement with near‐normal epithelium.

Conclusions:

Pc 4‐PDT is highly effective in treating virally induced (CRPV) papillomas in a murine model of RRP, and thus warrants further study as a treatment for HPV‐induced papillomas. Laryngoscope, 2010
Effect of defects on fatigue life of plates with fastener holes
Authors: Liu Y. S. , Gou B. W. , Liu J. , Yue Z. F.
Published: January 2010

The behavior of defects (inclusions and cavities) on fatigue life of plates with fastener holes under tensile loading has been analyzed. Special attentions have been paid on the influence of the size and location of defects on fatigue life of plates with fastener holes. Thirty‐five different finite element models of plates with different size and location of defects are established and the nominal stress method is used to estimate the fatigue lives of this models. The results show that there is a region whose center is the maximum stress point of the hole without defects. When the defect is located in this region, the influence of defects on fatigue life of plates with fastener holes is obvious. When the defects are far away form this region' center, the defects hardly influence the fatigue life of plates with fastener hole. The larger the size of the defect is, the bigger this region is. In this region, the larger the size of the defect and the shorter the distance between the defect and the region's center, the shorter the fatigue life of plates with fastener hole is.
Mild microscopic wear in the boundary lubrication regime
Authors: Bosman R.
Published: January 2010

The transition from a mild wear situation to a severe (adhesive) wear situation is of great interest to be able to design highly loaded concentrated contacts operating in the boundary lubricated regime. In this article a method is described to estimate this transition, based on a thermal criterion. It is stated that if a certain percentage of the contacting asperities transcends a critical temperature which is determined experimentally the transition from mild to severe wear takes place. The theory presented is validated with a model system and the results from experiments are is good agreement with the simulations.
Postconditioning protects skeletal muscle from ischemia‐reperfusion injury
Authors: Park Jong Woong , Kang Jong Woo , Jeon Woo Joo , Na Heung Sik
Published: January 2010

Ischemia‐reperfusion (I/R) injury caused by abrupt restoration of the circulation after prolonged ischemic insult induces significant morbidity after reconstructive microsurgery. The authors investigated whether a postconditioning (post‐con) procedure attenuated skeletal muscle I/R injury and protected muscular function. Three hours of complete ischemia was induced by occluding the muscular branches of rat extensor digitorum longus (EDL) muscle. The post‐con procedure was started at the end of ischemia and involved six cycles of 15 seconds of reperfusion followed by 15 seconds of re‐occlusion (3 minutes of total intervention) prior to initiating unlimited reperfusion. EDL muscle contractilities were compared with those of normal sides (no ischemic exposure), and experimental group results were also compared with control group results (3 hours of ischemia followed by full reperfusion without post‐con) at 3 hours and 5 days postreperfusion. Muscle wet weights, myeloperoxidase (MPO) activities, and histological results were also evaluated. The muscle contractilities in the post‐con group were significantly preserved at both 3 hours and 5 days postreperfusion as compared with ischemic controls. Decreased inflammatory cell infiltration, MPO activity, and wet weight of postconditioned EDL muscle suggested that post‐con attenuated acute inflammatory reactions induced by I/R. This study demonstrates that post‐con provides effective functional protection to skeletal muscles from I/R injury. © 2010 Wiley‐Liss, Inc. Microsurgery 2010.
A super‐toughened nylon 12 blends via anionic ring‐opening polymerization of lauryllactam in a twin screw extruder. Preparation, morphology, and mechanical properties
Authors: Du Libo , Yang Guisheng
Published: January 2010

Nylon 12 blends (BP) with nitrile‐butadiene ultrafine full‐vulcanized powdered rubber (NBUFPR) were successfully synthesized in a corotating intermeshing twin screw extruder via anionic ring‐opening polymerization of lauryllactam at 250°C. The in situ formed blends were characterized by mechanical test, fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. A brittle‐tough transition occurs when NBUFPR content is 4 wt%. And the notched Izod impact strength achieves 989 J m−1 when 5 wt% NBUFPR was added. Because of the good dispersion property of NBUFPR during the process ofreactive extrusion, the interparticle distance decrease remarkably. Besides, the in situ formed NBUFPR‐graft‐PA12 leads to better adhesion between the two phases. For comparison, another series of blends (BL) were also prepared by melt blending hydrolytic‐polymeric PA12 and NBUFPR in the same twin screw extruder. Brittle‐tough transition did not appear in BL blends within the same range of NBUFPR content. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
New computational method for prediction of interacting protein loop regions
Authors: Danielson Matthew L. , Lill Markus A.
Published: January 2010

Flexible loop regions of proteins play a crucial role in many biological functions such as protein–ligand recognition, enzymatic catalysis, and protein–protein association. To date, most computational methods that predict the conformational states of loops only focus on individual loop regions. However, loop regions are often spatially in close proximity to one another and their mutual interactions stabilize their conformations. We have developed a new method, titled CorLps, capable of simultaneously predicting such interacting loop regions. First, an ensemble of individual loop conformations is generated for each loop region. The members of the individual ensembles are combined and are accepted or rejected based on a steric clash filter. After a subsequent side‐chain optimization step, the resulting conformations of the interacting loops are ranked by the statistical scoring function DFIRE that originated from protein structure prediction. Our results show that predicting interacting loops with CorLps is superior to sequential prediction of the two interacting loop regions, and our method is comparable in accuracy to single loop predictions. Furthermore, improved predictive accuracy of the top‐ranked solution is achieved for 12‐residue length loop regions by diversifying the initial pool of individual loop conformations using a quality threshold clustering algorithm. Proteins 2010. © 2010 Wiley‐Liss, Inc.
Current status of membrane protein structure classification
Authors: Neumann Sindy , Fuchs Angelika , Mulkidjanian Armen , Frishman Dmitrij
Published: January 2010

For over 2 decades, continuous efforts to organize the jungle of available protein structures have been underway. Although a number of discrepancies between different classification approaches for soluble proteins have been reported, the classification of membrane proteins has so far not been comparatively studied because of the limited amount of available structural data. Here, we present an analysis of α‐helical membrane protein classification in the SCOP and CATH databases. In the current set of 63 α‐helical membrane protein chains having between 1 and 13 transmembrane helices, we observed a number of differently classified proteins both regarding their domain and fold assignment. The majority of all discrepancies affect single transmembrane helix, two helix hairpin, and four helix bundle domains, while domains with more than five helices are mostly classified consistently between SCOP and CATH. It thus appears that the structural constraints imposed by the lipid bilayer complicate the classification of membrane proteins with only few membrane‐spanning regions. This problem seems to be specific for membrane proteins as soluble four helix bundles, not restrained by the membrane, are more consistently classified by SCOP and CATH. Our findings indicate that the structural space of small membrane helix bundles is highly continuous such that even minor differences in individual classification procedures may lead to a significantly different classification. Membrane proteins with few helices and limited structural diversity only seem to be reasonably classifiable if the definition of a fold is adapted to include more fine‐grained structural features such as helix–helix interactions and reentrant regions. Proteins 2010. © 2010 Wiley‐Liss, Inc.
Negative differential conductivity in the hopping transport model
Authors: Jansson F. , Nenashev A. V. , Baranovskii S. D. , Gebhard F. , Österbacka R.
Published: January 2010

The effect of negative differential conductivity (NDC) in the hopping transport mode is studied by computer simulations. NDC is an important effect in a class of memory devices. Understanding the origin of NDC is vital to modeling these devices. Based on analytical arguments, it has been suggested by Shklovskii et al. that NDC can arise in the hopping model due to geometrical traps. Our computer simulations have confirmed this result. Another possibility is that the NDC is caused by Coulomb interaction between the charge carriers. This has been reported for special configurations of sites by Shin et al. We show that the NDC effect due to Coulomb interaction is not sensitive to the exact configuration of sites, and that it can appear also when the sites are placed randomly.
Doping of oligo(phenyl acetylene) with iodine vapour
Authors: Bakker R. , Weijers P. , van der Werf C. H. M. , Rath J. K. , Schropp R. E. I.
Published: January 2010

The doping with I2‐vapour and dopant effusion of thin films of conjugated oligomers are reported in this work. The layers have been created solvent‐free, by initiated chemical vapour deposition (iCVD). FTIR spectra show an interaction of the dopant with the phenyl ring of the oligomer. Reflectance/transmittance measurements showed a saturation of the dopant in the 400 nm thick layers after 40 min. The films change from transparent to brown‐green in the doping process and show a drastic increase in conductivity. The material is quite easily processable and can be grown at an adequate rate (∼3.5 nm/min) for thin film device applications.
UV‐sensitive optical sensors based on ITO‐gallium phosphide heterojunctions
Authors: Malik Oleksandr , Javier De la Hidalga‐Wade F. , Zúňiga‐Islas Carlos , Abundis Patiño Jesús H.
Published: January 2010

Design and characteristics of wide‐band UV sensors based on ITO/GaP heterostructures are discussed. Such sensors have perfect electrical parameters and high UV‐visible sensitivity in comparison with surface‐barrier structures using a semi‐transparent thin metal film as an electrode. Many applications require UV sensors with an effective rejection of visible radiation and a wide temperature operating interval.

For this aim, the theoretical modelling of extreme selective optical sensors with a double Ag/ITO thin film on the GaP surface, in which the thin silver film serves as a narrow bandpass filter at 320 nm, has been conducted. With this modelling the optimal thickness combination for the silver and ITO films was found for the maximum rejection of the sensitivity to visible radiation (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical processing devices based on a‐SiC:H multilayer architectures
Authors: Vieira M. , Louro P. , Vieira M. A. , Fernandes M. , Costa J. , Fantoni A. , Barata M. A.
Published: January 2010

Red, green and blue optical signals were directed to an a‐SiC:H multilayered device, each one with a specific transmission rate. The combined optical signal was analyzed by reading out, under different applied voltages, the generated photocurrent. Results show that when a chromatic time dependent wavelength combination with different transmission rates irradiates the multilayered structure, the device operates as a tunable wavelength filter and can be used in wavelength division multiplexing systems for short range communications. An application to fluorescent proteins detection is presented. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Erbium‐doped nanocrystalline silicon thin films produced by RF sputtering ‐ annealing effect on the Er emission
Authors: Cerqueira M. F. , Monteiro T. , Soares M. J. , Kozanecki A. , Alpuim P. , Alves E.
Published: January 2010

In the present work, erbium doped nanocrystalline silicon thin films were produced by reactive magnetron sputtering on glass substrates under different conditions (substrate temperature and Er content). The film structure was studied using Raman spectroscopy. The chemical composition was determined using the RBS technique. All the samples show sharp 4I13/2 → 4I15/2 intra‐4f11 emission of Er3+ related centres with its maximum positioned at the1.54 μm. However, the intensity of this transition (strongly dependent on the chemical composition of the matrix where the nanocrystals are embedded in and also on the structure of the matrix) changes after thermal annealing treatment. For the less crystalline samples our results show an increase of the Er3+ PL intensity and for the highly crystalline ones the Er emission vanishes even at low temperature. This behaviour was studied and explained in this work, on the basis of energy transfer between Si and Er ions (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Lifetime distribution of photoluminescence and radiative recombination rate of electron‐hole pairs in a‐Si:H
Authors: Ogihara Chisato , Morigaki Kazuo
Published: January 2010

Temperature variations of radiative recombination rates of electron‐hole pairs responsible for photoluminescence in a‐Si:H films have been analysed from the intensity, I, and the characteristic value of the lifetime, τ, obtained from frequency resolved spectroscopy. In a defective a‐Si:H film, the radiative recombinationrate increases with increasing temperature because of thermal excitation of the electrons and holes from the tail states to more ex‐tended tail states. In the case of a high‐quality a‐Si:H film, the temperature variation of Iτ–1 is explained by contributions from regions in the vicinity of the defects and the regions not affected by the defects (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The annealing temperature effect on the electrical properties of boron‐doped hydrogenated amorphous silicon a‐Si:H(B)
Authors: Khelifati N. , Tata S. , Rahal A. , Cherfi R. , Fedala A. , Kechouane M. , Mohammed‐Brahim T.
Published: January 2010

The effects of the boron incorporation on the physico‐chemical, optical and electric properties of hydrogenated amorphous silicon (a‐Si:H) films are presented. Boron‐doped hydrogenated amorphous silicon (a‐Si:H(B)) thin films were deposited by DC magnetron sputtering where silicon and boron are co‐pulverized. They are characterized by infrared, optical absorption and electrical conductivity measurements. The boron concentration varies between 1.3 1017 cm‐3 and 1.6 1022 cm‐3. The boron incorporation induced an increase in the refractive index and a decrease in the optical gap. This incorporation is followed by a decrease of the hydrogen film content, an improvement of the electrical conductivity under darkness (σd) with a decrease of its activation energy. These results can be related to the shift of the Fermi level towards the valence band due to boron doping, but then to a significant change of structural properties. The electrical measurements under white light showed that the incorporated boron conducts to a degradation of the light sensitivity of the films. Effect of annealing temperature on electrical conductivity also shows that boron atoms passivated by hydrogen can be activated from the annealing temperature through bridging Si‐H‐‐‐B bonds dissociation (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Performance and stability of low temperature hydrogenated amorphous silicon thin film transistors fabricated on stainless steel substrate
Authors: Kim Sung Hwan , Kim Sung Ki , Lee Jong‐Kwon , Lee Seok‐Woo , Lee Hong Koo , Peak Seung Han , Park Yong‐In , Kim Chang‐Dong , Hwang Yong Kee , Chung In‐Jae
Published: January 2010

The key development issues in the flexible displays are TFT backplane technology, which requires competitive device performance and low temperature process compatible with flexible substrate. Here, we have fabricated low temperature hydrogenated amorphous silicon thin film transistor on a stainless steel substrate coated with organic barrier layer. Then, we have studied initial device performance by varying plasma gas and pressure conditions at a low power and a low temperature during amorphous silicon and silicon nitride deposition steps. Also, we discuss the stability characteristics of this low temperature processed thin film transistor, which reveals enough possibility for use in flexible display applications. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Aged garlic extract inhibits CD36 expression in human macrophages via modulation of the PPARγ pathway
Authors: Morihara Naoaki , Ide Nagatoshi , Weiss Norbert
Published: January 2010

Expression of CD36 scavenger receptors on macrophages is involved in oxidized low‐density lipoprotein uptake and foam cell formation during atherosclerotic lesion development. We examined the effects of aged garlic extract (AGE), a garlic preparation enriched in water‐soluble cysteinyl moieties that increases cellular total thiols and glutathione concentrations, on CD36 expression in human monocytes/macrophages (THP‐1 cells and primary human monocytes). Compared to control, AGE (1–5 mg/mL) dose‐dependently and significantly suppressed CD36 expression up to by 61.8 ± 7.4% in THP‐1‐derived macrophages and up to 50.5 ± 7.1% in primary human macrophages, respectively. Furthermore, AGE prevented induction of CD36 expression by the peroxisome proliferator activator receptor (PPAR) γ agonist troglitazone, and decreased binding of nuclear proteins to a PPARγ response element. AGE showed a stronger inhibitory effect on CD36 expression in THP‐1 cells during simultaneous incubation with phorbol 12‐myristate 13‐acetate (PMA) compared to cells that had been pre‐incubated with PMA. Furthermore, AGE decreased CD11b expression in a dose‐dependent manner. These data indicate that AGE inhibits CD36 expression by modulating the PPARγ pathway in human macrophages and monocytes differentiation into macrophages, and suggests that the extract could be useful for the prevention of atherosclerotic lesions. Copyright © 2010 John Wiley & Sons, Ltd.
Ab initio calculations of surface electronic states in indium oxide
Authors: Fuks David , Shapiro Dina , Kiv Arnold , Golovanov Vyacheslav , Liu Chung‐Chiun
Published: January 2010

A slab approach in the framework of ab initio calculations was applied to study surface electronic states in In2O3 crystal. Density functional theory (DFT) calculations were carried out employing the WIEN 2k code and using the full potential method with Augmented Plane Waves + local orbitals (APW+lo) formalism. Total and partial DOS (Density of States) were calculated for In and O atoms in two upper (110) surface layers. Comparison of total and partial DOS allowed determining a contribution of electronic states of different In and O surface atoms into formation of surface electronic spectra and corresponding chemical bonds. A dominant ionic character of chemical bonds in In2O3 is found. Calculations were performed for three slab models with different geometry parameters. It was shown that an optimal ratio between the whole vertical size of a supercell and the vertical size of atomic cluster has to be chosen. The size of vacuum region in the slab model influences significantly on the reliability of calculated characteristics of the surface electronic structure. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Structure and optical spectra of bis(pyrrol‐2‐ylmethyleneamine) complexes: A DFT and TDDFT study of the self‐assembly complexes of bis(pyrrol‐2‐ylmethyleneamine) ligands linked by alkyl spacers with Cu(II)
Authors: Li Wei , Yang Feng , Wang Zhengdong
Published: January 2010

The UV‐Vis absorption spectra of self‐assembly Cu (II) complexes for bis(pyrrol‐2‐ylmethyleneamine) linked by alkyl(CH2)n(n = 2,3,4,6) spacers were recorded. The ground‐state geometries and electronic structures were investigated by density functional theory employing generalized‐gradient approximation Perdew‐Burke‐Ernzerhof (PBE) and hybrid B3LYP (20% Ex,HF)and PBE0 (25% Ex,HF) functional, in conjugation with four basis set combinations.[BS1:6‐31G(d); BS2:Lanl2dz for Cu and 6‐31G(d) for C,H,N; BS3:6‐31+G(d); BS4:6‐311+G(d,p) for C,H,N and Lanl2dz for Cu]. Compared the optimized geometries with XRD structures, it was found that the choice of methods appeared to have a more pronounced effect on structure than that of the basis set. PBE0/BS4 optimized geometries provide the best agreement with XRD experimental results and the mean absolute errors for bond length is 0.018 Å and for bond angle is 2.1°. Transition excited states of complexes 1–4 in the gas phase and in CH2ClCH2Cl solution have been studied by the time‐dependent density functional theory in conjugated with the Polarizable Continuum Model. Pure PBE and hybrid B3LYP, PBE0 functionals, as well as BS1, BS2, and BS5 [6‐311++G (d,p)] were selected. Calculations indicate that PBE functional provides more accurate descriptions on main UV‐vis absorptions than B3LYP and PBE0 functionals. The strongest absorption bands located at 338–356 nm are due to intraligand charge transfer (ILCT) transitions, a mixed‐character ILCT + metal‐ligand charge transfer (MLCT) absorptions are calculated at 280–291 nm, the shoulder bands located at 250–257 nm mainly arise from MLCT or ligand‐metal charge transfer transitions. Alkyl spacer does not play a crucial role on the main electron transitions. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Determination of some descriptors of the real world working on the fundamental identity of the basic concept and the origin of the electronegativity and the global hardness of atoms, part 1: Evaluation of internuclear bond distance of some heteronuclear diatomics
Authors: Ghosh Dulal C. , Islam Nazmul
Published: January 2010

In our previous report, we have posited that there is much conceptual commonality between the two fundamental theoretical descriptors of chemistry and physics—the electronegativity and the hardness and both the fundamental descriptors originate from the same source—the electron attracting power of the screened nucleus upon the valence electrons. We have discovered the surprising result that if one measures hardness, the electronegativity is simultaneously measured and vice versa. In the present report, we have calculated the internuclear bond distances of a series of diatomic molecules invoking the ansatz for computing such bond distances in terms of the electronegativities (χ) of the atoms. We have just substituted the electronegativities (χ) by the global hardness (η) in the well established ansatz for computing bond distances of Ray et al. We have found that the computed internuclear distances are very close to the experimental bond distances. This is one validity test of our hypothesis that the electronegativity and global hardness are two different labels or legends of one and the same fundamental property of the atoms. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Kernel energy method applied to an energetic nitrate ester
Authors: Huang Lulu , Massa Lou
Published: January 2010

A recent synthesis results in a nitrate ester explosive C6N6O16H8 (Hisk75), composed of four nitrate ester groups (ONO2) and two nitro groups (NO2), with the property of being solid at room temperature with a low‐melting point allowing the convenience of poured mold casting (Chavez et al., Angew Chem Int Ed 2008, 47, 8307). Using the crystal geometry, we have calculated the quantum chemical interaction energies, including basis set superposition errors between nearest neighboring molecules. Using quantum mechanics and the computer program CHEETA, we have calculated the explosive parameters of this new molecule, comparing to those of HMX, corroborating previous estimates of these same parameters. Calculations confirm this compound to be one of the best performing high‐energy/high‐density explosives. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Whether there is a hardness equalization principle analogous to the electronegativity equalization principle—A quest
Authors: Ghosh Dulal C. , Islam Nazmul
Published: January 2010

In this report, we have attempted to explore whether the hardness equalization principle can be conceived analogous to the well‐established electronegativity equalization principle. We have relied upon the fact that the hardness, like the electronegativity, is a qualitative property, and there is commonality in the basic philosophy of the origin and the operational significance of these two fundamental descriptors—the electronegativity and the hardness of atoms in physics and chemistry. Starting from the empirical radial dependent formula of computing the hardness of atoms suggested by us, we have derived an ansatz of the molecular hardness assuming that hardness equalization principle is operative and justifiably valid. For a validity test, we have applied the suggested ansatz to compute the hardness of as many as four sets of compounds with widely divergent physical and chemical nature. As hardness is not an experimentally measurable property, there is no benchmark to perform any validity test of our computed data. We have, therefore, computed the hardness data of these four different sets of the compound invoking the approximate and operational formula of Parr and Pearson, (I − A)/2, to evaluate hardness values and to compute I and A, we have invoked Koopmans' theorem and an ab initio quantum chemical method. We have observed that there is a close correlation between the four sets of hardness data computed through the semi‐empirical ansatz of this work and the quantum mechanical method. Thus, it appears that the ansatz of computing molecular hardness derived on the basis of the hardness equalization principle is efficacious in computing molecular hardness. The detailed comparative study suggests that the paradigm of the hardness equalization principle may be another law of nature like the established electronegativity equalization principle. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Modeling, experimenting, and improving skid steering on a 6 × 6 all‐terrain mobile platform
Authors: Fauroux J.‐C. , Vaslin P.
Published: January 2010

Multiple‐wheel all‐terrain vehicles without a steering system must use great amounts of power when skid steering. Skid steering is modeled with emphasis put on the ground contact forces of the wheels according to the mass distribution of the vehicle. To increase steering efficiency, it is possible to modify the distribution of the normal contact forces on the wheels. This paper focuses on two aspects: first, it provides a model and an experimental study of skid steering on an all‐road 6 × 6 electric wheelchair, the Kokoon mobile platform. Second, it studies two configurations of the distribution of the normal forces on the six wheels, obtained via suspension adjustments. This was both modeled and experimented. Contact forces were measured with a six‐component force plate. The first results show that skid steering can be substantially improved by only minor adjustments to the suspensions. This setting decreases the required longitudinal forces applied by the engines and improves the steering ability of the vehicle or robot. Skid‐steering characteristic parameters, such as the position of the center of rotation and absorbed skid power, are also dealt with in this paper. © 2010 Wiley Periodicals, Inc.
Error minimization in the envelope method for the determination of optical constants of a thin film
Authors: Kar Meenakshi
Published: January 2010

The algorithm for the determination of optical constants of a weakly absorbing thin film from the envelope method has been modified to minimize the error in the estimated values of extinction coefficient (k) as a function of wavelength. The refinement procedure is based on an extension of interference order adjustment method used for improving the estimated values of film thickness d and wavelength‐dependent refractive index n from the envelope method. The proposed modification when applied to a hypothetical as well as an experimental film is found to work well over a wide spectral region. Copyright © 2010 John Wiley & Sons, Ltd.
Effect of cyanoguanidine‐metal and urea‐metal complexes on the thermal degradation of poly(vinyl chloride)
Authors: Abdel‐Naby Abir S. , Al‐Ghamdi Refaa F. , Al‐Ghamdi Azza A.
Published: January 2010

Tin, nickel, cobalt, zinc, and copper complexes of cyanoguanidine and urea were synthesized and investigated as thermal stabilizers for rigid poly(vinyl chloride) at 180°C in air. Their stabilizing efficiencies were evaluated by measuring the induction period (the period during which no evolved hydrogen chloride could be detected) and the rate of dehydrochlorination as determined by continuous potentiometric measurements, in addition to the extent of discoloration. The results clearly revealed the greater efficiency of all of the investigated metal complexes as compared to those of well‐recognized reference stabilizers. The tin complex always exhibited the highest efficiency irrespective of the type of ligand used. The nickel and cobalt complexes also possessed high stabilizing efficiencies. The order of the stabilizing potency of the various metal complexes was Sn ⋙ Co, Ni ≫ Zn, Cu. Combining the ligand itself with dimethyltin‐s,s′‐bis (isooctyl thioglycolate), as a reference stabilizer containing a tin atom, led to a true synergism. This synergistic effect might be attributed to the formation in situ of a complex between the ligand and the tin atom. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers
Opportunistic delay‐margin‐based resource allocation for next‐generation wireless networks
Authors: Ho Quang‐Dung , Ashour Mohamed , Le‐Ngoc Tho
Published: January 2010

This paper studies and develops efficient traffic management techniques for downlink transmission at the base station (BS) of multi‐service IP‐based networks by combining quality‐of‐service (QoS) provision and opportunistic wireless resource allocation. A delay‐margin‐based scheduling (DMS) for downlink traffic flows based on the delays that each packet has experienced up to the BS is proposed. The instantaneous delay margin, represented by the difference between the required and instantaneous delays, quantifies how urgent the packet is, and thus it can determine the queuing priority that should be given to the packet. The proposed DMS is further integrated with the opportunistic scheduling (OPS) to develop various queueing architectures to increase the wireless channel bandwidth efficiency. Different proposed integration approaches are investigated and compared in terms of delay outage probability and wireless channel bandwidth efficiency by simulation. Copyright © 2010 John Wiley & Sons, Ltd.
Stability of a gradient elastic beam compressed by non‐conservative forces
Authors: Lazopoulos K.A. , Lazopoulos A.K.
Published: January 2010

The critical loads for five non‐conservative problems are defined under the context of gradient elasticity theory of a beam. The first problem deals with the stability of a gradient elastic beam compressed by a follower force (Beck's problem) and the second deals with the stability of a gradient elastic beam compressed by a force with a fixed line of action (Rent's problem). The governing dynamic equation with the boundary conditions is formulated on the bases of simple linear elasticity theory with the beam mass concentrated on the moving end. Also the case with uniform distribution of the mass along the beam will be considered. Further the effect of an additional conservative force acting on the moving end of the beam will also be discussed. Numerical applications indicate that although the surface energy term does not have a substantial effect, the intrinsic length due to gradient elasticity is of major importance. In fact, it increases of the critical load.