bluuebunny/crossref_metadata_2025 huggingface dataset:
Uniform exponential decay of the free energy for Voronoi finite volume discretized reaction‐diffusion systems
Authors: Glitzky Annegret
Published: September 2011

Our focus are energy estimates for discretized reaction‐diffusion systems for a finite number of species. We introduce a discretization scheme (Voronoi finite volume in space and fully implicit in time) which has the special property that it preserves the main features of the continuous systems, namely positivity, dissipativity and flux conservation.

For a class of Voronoi finite volume meshes we investigate thermodynamic equilibria and prove for solutions to the evolution system the monotone and exponential decay of the discrete free energy to its equilibrium value with a unified rate of decay for this class of discretizations. The fundamental idea is an estimate of the free energy by the dissipation rate which is proved indirectly by taking into account sequences of Voronoi finite volume meshes. Essential ingredient in that proof is a discrete Sobolev‐Poincaré inequality.
Thin film equations with soluble surfactant and gravity: Modeling and stability of steady states
Authors: Escher Joachim , Hillairet Matthieu , Laurençot Philippe , Walker Christoph
Published: September 2011

A thin film on a horizontal solid substrate and coated with a soluble surfactant is considered. The governing degenerate parabolic equations for the film height and the surfactant concentrations on the surface and in the bulk are derived using a lubrication approximation when gravity is taken into account. It is shown that the steady states are asymptotically stable.
Asthma and Rhinitis During Pregnancy
Authors: Namazy Jennifer A. , Schatz Michael
Published: September 2011

Pregnancy may be complicated by new‐onset or preexisting rhinitis, or asthma. This article reviews the recognition and management of rhinitis and asthma during pregnancy, as well as general principles of medication use during pregnancy. Asthma is one of the most common potentially serious medical problems to complicate pregnancy, and chronic rhinitis is even more common in pregnant women. Both conditions may substantially affect maternal quality of life and directly or indirectly affect the pregnancy. Optimal management of asthma and rhinitis during pregnancy is thus important for both mother and baby. This article reviews the assessment and management of rhinitis and asthma in pregnant women. Mt Sinai J Med 78:661–670, 2011. © 2011 Mount Sinai School of Medicine
Food Allergy
Authors: Sicherer Scott H.
Published: September 2011

1 Food allergy appears to be increasing in prevalence and is estimated to affect >2% and possibly up to 10% of the population. Food allergies are defined by an immune response triggered by food proteins. Emerging data suggest that carbohydrate moieties on food proteins, specifically mammalian meats, may also elicit allergic responses. Food is the most common trigger of anaphylaxis in the community, which can be fatal. The underlying mechanisms of food allergy usually involve food‐specific immunoglobulin E antibodies, but cell‐mediated disorders account for a variety of chronic or subacute skin and gastrointestinal reactions. Eosinophilic esophagitis is an emerging food‐related chronic disorder. The diagnosis of food allergy is complicated by the observation that detection of food‐specific immunoglobulin E (sensitization) does not necessarily indicate clinical allergy. Diagnosis requires a careful medical history, laboratory studies, and, in many cases, oral food challenges to confirm a diagnosis. Novel diagnostic methods, many of which rely upon evaluating immune responses to specific food proteins or epitopes, may improve diagnosis and prognosis in the future. Current management relies upon allergen avoidance and preparation to promptly treat severe reactions with epinephrine. Studies suggest that some children with milk or egg allergy might tolerate extensively heated forms, for example milk or egg baked into muffins, without symptoms and possibly with some immunotherapeutic benefits. Novel therapeutic strategies are under study, including oral and sublingual immunotherapy, Chinese herbal medicine, anti–immunoglobulin E antibodies, and modified vaccines. Mt Sinai J Med 78:683–696, 2011. © 2011 Mount Sinai School of Medicine
Rituximab as potential therapy for paraneoplastic cerebellar degeneration in pediatric Hodgkin disease
Authors: Yeo Kee Kiat , Walter Andrew W. , Miller Robin E , Dalmau Josep
Published: September 2011

Paraneoplastic cerebellar degeneration (PCD) is a rare neurological syndrome associated with lung cancer, breast adenocarcinoma, ovarian adenocarcinoma, and Hodgkin disease. It is rarely seen in pediatrics. We report a case of a 10‐year‐old boy with a 2‐year prodrome that led to a diagnosis of PCD in association with stage IV Hodgkin disease. He received radiation and chemotherapy for his Hodgkin disease with resolution of his lymphoma. Based on promising data in adults on the efficacy of rituximab over other immunosuppressive agents in paraneoplastic disorders, he was treated with rituximab with marked improvement of the cerebellar syndrome. Pediatr Blood Cancer 2012; 58: 986–987. © 2011 Wiley Periodicals, Inc.
Enhancement of POM thermooxidation resistance through POSS nanoparticles
Authors: Vilà Ramirez Narciso , Sanchez‐Soto Miguel , Illescas Silvia
Published: September 2011

Thermooxidative degradation at and beyond processing temperatures has been carried out on polyoxymethylene (POM) enhanced with four different types of POSS, being Glycidyl, GlycidylIsobutyl, Aminopropylisobutyl, and Poly(ethylene glycol). The quantification of such degradation was carried out through FTIR spectrography, color spectrophotometry, and thermogravimetric analysis methods. The results showed that the presence of POSS in the blend improves dramatically the thermal stability of the POM matrix. The best performance was found with Aminopropylisobutyl, whereby the onset of degradation temperature increased by more than 50°C. Said improvement is referred to the conditions where the nanocomposite developed only 2% of carbonyl yield and 8% of yellowing of the 100% deterioration suffered by the standard POM copolymer. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Thiazolothiazole‐containing polythiophenes with low HOMO level and high hole mobility for polymer solar cells
Authors: Shi Qinqin , Fan Haijun , Liu Yao , Chen Jianming , Shuai Zhigang , Hu Wenping , Li Yongfang , Zhan Xiaowei
Published: September 2011

Two regiochemically defined polythiophenes containing thiazolothiazole acceptor unit were synthesized by palladium(0)‐catalyzed Stille coupling reaction. The thermal, electrochemical, optical, charge transport, and photovoltaic properties of these copolymers were examined. Compared to P1 with head‐to‐head coupling of two middle thiophenes, P2 with head‐to‐tail coupling of two middle thiophenes exhibits 40 nm red shift of absorption spectrum in film and 0.3 eV higher HOMO level. Both polymers exhibit field‐effect hole mobility as high as 0.02 cm2 V−1 s−1. Polymer solar cells (PSCs) were fabricated based on the blend of the polymers and methanofullerene[6,6]‐phenyl C71‐butyric acid methyl ester (PC71BM). The PSC based on P1:PC71BM (1:2, w/w) exhibits a power conversion efficiency of 2.7% under AM 1.5, 100 mW cm−2, two times of that based on P2:PC71BM. The higher efficiency is attributed to lower HOMO (−5.6 eV) and smaller phase separation scale in P1:PC71BM blend. Tiny change in thiophene connection of P1 and P2 lead to great difference in HOMO, phase separation scale, and efficiency of their photovoltaic devices. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Prescont: Predicting protein‐protein interfaces utilizing four residue properties
Authors: Zellner Hermann , Staudigel Martin , Trenner Thomas , Bittkowski Meik , Wolowski Vincent , Icking Christian , Merkl Rainer
Published: September 2011

An important task of computational biology is to identify those parts of a polypeptide chain, which are involved in interactions with other proteins. For this purpose, we have developed the program PresCont, which predicts in a robust manner amino acids that constitute protein‐protein interfaces (PPIs). PresCont reaches state‐of‐the‐art classification quality on the basis of only four residue properties that can be readily deduced from the 3D structure of an individual protein and a multiple sequence alignment (MSA) composed of homologs. The core of PresCont is a support vector machine, which assesses solvent‐accessible surface area, hydrophobicity, conservation, and the local environment of each amino acid on the protein surface. For training and performance testing, we compiled three nonoverlapping datasets consisting of permanently formed or transient complexes, respectively. A comparison with SPPIDER, ProMate, and meta‐PPISP showed that PresCont compares favorably with these highly sophisticated programs, and that its prediction quality is less dependent on the type of protein complex being considered. This balance is due to a mutual compensation of classification weaknesses observed for individual properties: For PPIs of permanent complexes, solvent‐accessible surface and hydrophobicity contribute most to classification quality, for PPIs of transient complexes, the assessment of the local environment is most significant. Moreover, we show that for permanent complexes a segmentation of PPIs into core and rim residues has only a moderate influence on prediction quality. PresCont is available as a web service at http://www‐bioinf.uni‐regensburg.de/. Proteins 2012; © 2011 Wiley Periodicals, Inc.
Urbach tail and bandgap analysis in near stoichiometric LiNbO3 crystals
Authors: Bhatt R. , Bhaumik I. , Ganesamoorthy S. , Karnal A. K. , Swami M. K. , Patel H. S. , Gupta P. K.
Published: September 2011

Energy of the indirect and direct optical bandgap of near‐stoichiometric lithium niobate (nSLN) crystals is evaluated by optical absorption measurement. The value of the indirect bandgap (3.95 eV) is consistent with the earlier reports. However, the direct bandgap energy of 4.12 eV is higher than the previously reported experimental value (3.68 eV). The direct bandgap energy obtained here is closer to the recent theoretical value estimated by Thierfelder et al. [Phys. Status Solidi C 7, 362 (2010)] in comparison to the previously predicted value by Ching et al. [Phys. Rev. B 50, 1992 (1994)]. The phonons involved in the indirect allowed transitions have energies ∼85 meV (685 cm−1) and are identified as the E(TO9) and E(LO8) optical phonon modes from the Raman scattering measurement.
Evidence for Fe2+ in Wurtzite Coordination: Iron Doping Stabilizes ZnO Nanoparticles
Authors: Xiao Jianping , Kuc Agnieszka , Pokhrel Suman , Schowalter Marco , Parlapalli Satyam , Rosenauer Andreas , Frauenheim Thomas , Mädler Lutz , Pettersson Lars G. M. , Heine Thomas
Published: September 2011

First‐principles calculations are used to investigate the structural and electronic properties of Fe‐doped ZnO nanoparticles. Based on extensive validation studies surveying various density functionals, the hybrid functional PBE0 is employed to calculate the structures, formation energies, and electronic properties of Fe in ZnO with Fe concentrations of 6.25, 12.5, and 18.75 at%. Substitution of Zn by Fe, zinc vacancies, and interstitial oxygen defects is studied. High‐resolution inner‐shell electron energy loss spectroscopy measurements and X‐ray absorption near‐edge structure calculations of Fe and O atoms are performed. The results show that Fe‐doped ZnO nanoparticles are structurally and energetically more stable than the isolated FeO (rocksalt) and ZnO (wurtzite) phases. The Fe dopants distribute homogeneously in ZnO nanoparticles and do not significantly alter the host ZnO lattice parameters. Simulations of the absorption spectra demonstrate that Fe2+ dominates in the Fe‐doped ZnO nanoparticles reported recently, whereas Fe3+ is present only as a trace.
Nanodiamond as a Vector for siRNA Delivery to Ewing Sarcoma Cells
Authors: Alhaddad Anna , Adam Marie‐Pierre , Botsoa Jacques , Dantelle Géraldine , Perruchas Sandrine , Gacoin Thierry , Mansuy Christelle , Lavielle Solange , Malvy Claude , Treussart François , Bertrand Jean‐Rémi
Published: September 2011

The ability of diamond nanoparticles (nanodiamonds, NDs) to deliver small interfering RNA (siRNA) into Ewing sarcoma cells is investigated with a view to the possibility of in‐vivo anticancer nucleic‐acid drug delivery. siRNA is adsorbed onto NDs that are coated with cationic polymer. Cell uptake of NDs is demonstrated by taking advantage of the NDs’ intrinsic fluorescence from embedded color‐center defects. Cell toxicity of these coated NDs is shown to be low. Consistent with the internalization efficacy, a specific inhibition of EWS/Fli‐1 gene expression is shown at the mRNA and protein level by the ND‐vectorized siRNA in a serum‐containing medium.
A Preoperative Predictive Scoring System for Postoperative Pancreatic Fistula after Pancreaticoduodenectomy
Authors: Yamamoto Yusuke , Sakamoto Yoshihiro , Nara Satoshi , Esaki Minoru , Shimada Kazuaki , Kosuge Tomoo
Published: September 2011

Background

Postoperative pancreatic fistula (POPF) remains a leading cause of morbidity after pancreaticoduodenectomy (PD). In the present study we sought to establish a preoperative scoring system with which to predict this complication.

Patients and methods

The clinical records of 387 consecutive patients who underwent PD for periampullary tumor between 2004 and 2009 were reviewed retrospectively. Patients were divided into two groups; 279 consecutive patients constituted the study group and the next 108 patients constituted the validation group. Univariate and multivariate logistic regression analyses were performed using preoperative and surgical factors potentially influencing grade B or C POPF in the study group, and a score to predict POPF was constructed. This score was confirmed in the validation group.

Results

In the study group, grade A POPF was recognized in 45 patients (16%), grade B in 98 (35%), and grade C in 5 (2%). A preoperative predictive scoring system for POPF (0‐7 points) was constructed using the following 5 factors; main pancreatic duct index <0.25 (2 points), away from portal vein on computed tomography (2 points), disease other than pancreatic cancer (1 point), male (1 point), and intra‐abdominal thickness >65 mm (1 point). The nomogram showed an area under the curve (AUC) of 0.808. This scoring system was highly predictive for grade B or C POPF in the validation group (AUC = 0.834).

Conclusions

The present scoring system satisfactorily predicted the occurrence of POPF and thus will be useful for the perioperative risk management of patients undergoing PD in a high‐volume center hospital.
Dietary plasma proteins attenuate the innate immunity response in a mouse model of acute lung injury
Authors: Maijó Mònica , Miró Lluïsa , Polo Javier , Campbell Joy , Russell Louis , Crenshaw Joe , Weaver Eric , Moretó Miquel , Pérez-Bosque Anna
Published: September 2011

We examined whether oral plasma protein supplements affect the innate immune response in a model of acute lung inflammation. Mice were fed diets supplemented with 8 % spray-dried plasma (SDP) or 2 % plasma Ig concentrate (IC) from day 19 (weaning) until day 34. The mice were challenged with intranasal lipopolysaccharide (LPS) at day 33 (and killed 24 h later for cytokine and leucocyte analyses) or at day 34 (and killed 6 h later for cytokine determinations). In bronchoalveolar lavage fluid (BALF), LPS increased the number of leucocytes by twenty-sevenfold, an effect that was partly prevented by both SDP and IC, and by twentyfold the percentage of activated monocytes, which was partly prevented by SDP. In the lung tissue, LPS increased the infiltrated leucocytes, and this effect was prevented in part by SDP. In unchallenged mice, both SDP and IC diets reduced the percentage of resident neutrophils and monocytes (P < 0·05). In the blood, both SDP and IC completely prevented LPS-dependent monocyte activation (CD14+; P < 0·05). LPS dramatically increased the concentration of cytokines (TNF-α, IL-1α, IL-6, granulocyte-macrophage colony-stimulating factor and granulocyte colony-stimulating factor) and chemokines (CXCL1, CCL2, CCL3 and CCL4) in BALF. The acute response of cytokine production was reduced by 20–80 % by both SDP and IC. For chemokines, plasma supplements had no effect on LPS-induced CXCL1 expression but significantly reduced CCL2, CCL3 and CCL4 production (P < 0·05). The results support the view that dietary plasma proteins can be used to attenuate endotoxin-associated lung inflammation.
Measurement and error of hoof horn growth rate in sheep
Authors: SHELTON J. , USHERWOOD N. M. , WAPENAAR W. , BRENNAN M. L. , GREEN L. E.
Published: September 2011

Determining the rate of hoof horn growth in sheep is important for understanding the physiology and pathology of the foot and the impact of the environment and the treatment of diseased feet on foot health. It could lead to improved understanding of the interaction between hoof horn and pasture/barn floor characteristics and in methods for prevention and treatment of ovine foot diseases. In the current study, the hoof horn was measured using a previously tested protocol on all eight digits of 21 healthy yearling mule ewes on a farm in North Wales on four occasions over a period of 53 days. The mean hoof horn growth rate was 0·11 mm (s.e.m. 0·02) per day; the residual error variance was 0·024 and the R2 was 0·245. There were no significant differences between hoof horn growth rates in front and hind feet or between medial and lateral claws or over time.
Atlas of the barnacles on marine vertebrates in Japanese waters including taxonomic review of superfamily Coronuloidea (Cirripedia: Thoracica)
Authors: Hayashi Ryota
Published: September 2011

Barnacles of the superfamily Coronuloidea are epibiotic on marine vertebrates. In the present study, 13 species in 9 genera of coronulid barnacles were collected in Japan and a distributional map of epibiotic barnacles (Cirripedia: Thoracica: Coronuloidea) in Japanese waters is presented. The hosts including sea turtles, whales and dolphins and 4 species of these barnacles are listed as new records for Japan.
Stability and change in the intergenerational family: a convoy approach
Authors: ANTONUCCI TONI C. , BIRDITT KIRA S. , SHERMAN CAREY W. , TRINH SARAH
Published: September 2011

There have been fundamental changes in the intergenerational family, and yet families continue to be an important part of people's lives. We use the convoy model to describe the factors that influence supportive relations within intergenerational families, beginning with a description of the changing structure of the intergenerational family. We next outline support exchanges, detailing how personal characteristics, especially gender, race, age and socio-economic status, and situational characteristics, in particular family structure and intergenerational context, influence support exchanges. Instrumental and emotional family exchanges are described, with special attention to the unique circumstances of care-giving in intergenerational families. We also examine the importance of recognising differences in the quality of intergenerational relations, again noting the influence of personal and situational characteristics. Variations in support quality,e.g. positive, negative and ambivalent, and its influence on wellbeing are discussed. As families and individuals change, differences emerge at the individual, family and societal levels. We consider the implications of changes and stability in intergenerational relations and make recommendations about how best to envisage and plan future intergenerational family support. Societies with fewer resources as well as individuals and families with diverse individual histories must be innovative and creative in meeting the needs of older people as well as those of all family members.
Adjusting the cut: fashion, the body and age on the UK high street
Authors: TWIGG JULIA
Published: September 2011

The article explores the interplay between bodily and cultural ageing in the provision of clothing for older women, examining how design directors of UK clothing retailers act as cultural mediators, shaping the ways in which later years are imagined, experienced and performed at an embodied level. Based on interviews with clothing retailers with a significant involvement with the older market: Marks & Spencer, George at Asda, Jaeger, Viyella and Edinburgh Woollen Mill, it analyses the contexts in which they design, discussing: the potential of the grey market; the association of fashion and youthfulness; and the tensions between lifestyle and age in the formation of the market. It explores the ways in which they adjust the cut, colour and style of clothes to meet the requirements of older bodies and the changing cultural interpretations of these, addressing debates around the interplay of bodily and cultural ageing, and the role of consumption in the constitution of age. Reflecting both the cultural and material turns, it argues for the need to expand the social gerontology imaginary to encompass wider sources shaping the meanings of later years.
Human Factors and Maritime Safety
Authors: Chauvin Christine
Published: September 2011

This paper presents key models and concepts developed in psychology which help to understand the role of human factors in complex systems. It aims to explain their significance for anyone who wants to analyze the role of human factors in maritime accidents. Reason (1990, 1997, 2000) makes a crucial distinction between “active failures” that are made by first-line operators (captain, officers or members of a crew) and “latent failures” that are deeper causes and upstream factors concerning people who are at a distance from the accident. In agreement with this theoretical framework, this paper proposes examining the role of human factors in maritime accidents at three different levels:i) the level of individual – and namely cognitive – factors of first-line operators,ii) the level of social – and namely interpersonal – factors andiii) the level of systemic or organizational factors which correspond to “latent failures”. For each level, the main and recent contributions of the human and social sciences are presented and then used to analyze an emblematic accident.
Modelling Port Water Collision Risk Using Traffic Conflicts
Authors: Debnath Ashim Kumar , Chin Hoong Chor , Haque Md. Mazharul
Published: September 2011

Navigational collisions are one of the major safety concerns for many seaports. Despite the extent of work recently done on collision risk analysis in port waters, little is known about the influential factors of the risk. This paper develops a technique for modelling collision risks in port waterways in order to examine the associations between the risks and the geometric, traffic, and regulatory control characteristics of waterways. A binomial logistic model, which accounts for the correlations in the risks of a particular fairway at different time periods, is derived from traffic conflicts and calibrated for the Singapore port fairways. Results show that the fairways attached to shoreline, traffic intersection and international fairway attribute higher risks, whereas those attached to confined water and local fairway possess lower risks. Higher risks are also found in the fairways featuring higher degree of bend, lower depth of water, higher numbers of cardinal and isolated danger marks, higher density of moving ships and lower operating speed. The risks are also found to be higher at night.
The language features and architecture of B-Prolog
Authors: ZHOU NENG-FA
Published: September 2011

B-Prolog is a high-performance implementation of the standard Prolog language with several extensions including matching clauses, action rules for event handling, finite-domain constraint solving, arrays and hash tables, declarative loop constructs, and tabling. The B-Prolog system is based on the Tree-Oriented Abstract Machine (TOAM) architecture which differs from the Warren Abstract Machine (WAM) mainly in that (1) arguments are passed old fashionedly through the stack, (2) only one frame is used for each predicate call, and (3) instructions are provided for encoding matching trees. The most recent architecture, called TOAM Jr., departs further from the WAM in that it employs no registers for arguments or temporary variables, and provides variable-size instructions for encoding predicate calls. This paper gives an overview of the language features and a detailed description of the TOAM Jr. architecture, including architectural support for action rules and tabling.
Thioamide quenching of intrinsic protein fluorescence
Authors: Goldberg Jacob M. , Wissner Rebecca F. , Klein Alyssa M. , Petersson E. James
Published: September 2011

Thioamides quench tryptophan and tyrosine fluorescence in a distance-dependent manner and thus can be used to monitor the binding of thioamide-containing peptides to proteins.
(−)‐Epigallocatechin gallate suppresses adipocyte differentiation through the MEK/ERK and PI3K/Akt pathways
Authors: Kim Hyojung , Sakamoto Kazuichi
Published: September 2011

EGCG [(−)‐epigallocatechin gallate], tea catechin, is one of the compounds that has been reported to act against obesity and diabetes. To determine the effect of EGCG on adipocyte differentiation, we treated 3T3‐L1 preadipocytes with different catechins. Oil Red O staining showed significantly reduced intracellular lipid accumulation, especially with EGCG. Cell cycle analysis showed that EGCG inhibited cell proliferation by disturbing the cell cycle during the clonal expansion of 3T3‐L1. RT‐PCR (real‐time PCR) demonstrated that EGCG noticeably reduced mRNA expression of PPARα (peroxisome proliferator‐activated receptor α), C/EBPα (CCAAT/enhancer‐binding protein α) and FoxO1 (forkhead box class O1). EGCG also caused a significant decrease in the transcription of FoxO1 – the forkhead transcription factor class O1 involved in adipocyte differentiation – via the PI3K (phosphoinositide 3‐kinase)/Akt and MEK [MAPK (mitogen‐activated protein kinase)/ERK (extracellular‐signal‐regulated kinase) kinase] pathways. These results suggest that EGCG suppresses the clonal expansion of adipocytes by inactivating FoxO1 via insulin signalling and stress‐dependent MAPK pathways.
Charging phenomena in dielectric/semiconductor heterostructures during x-ray photoelectron spectroscopy measurements
Authors: Perego M. , Seguini G.
Published: September 2011

The determination of the valence band offset (VBO) by x-ray photoelectron spectroscopy (XPS) is commonly performed using the so-called Kraut’s method that was developed for VBO determination in semiconductor/semiconductor heterojunctions. Although the physical model, which is the basis of the method, can be safely extended to dielectric/semiconductor (D/S) heterojunctions, in these systems a careful evaluation of the experimental results is necessary due to the differential charging phenomena originating at D/S interface during x-ray bombardment. As a consequence, precise determination of the VBO requires an accurate calibration of the energy scale in order to remove artifacts induced by the progressive charging of the oxide during the XPS measurement. In this work a detailed analysis of the band alignment between e-beam evaporated amorphous HfO2 films and Si substrates is reported. The HfO2/Si heterojunction was selected as a prototype for this study since HfO2 based dielectrics have already been implemented as gate dielectrics in real devices and have been the subject of a wide number of publications providing controversial results in terms of VBO values. A clear dependence of the binding energy of the Hf 4f and O 1s core lines on the thickness of the HfO2 film is identified. The time evolution of these signals indicates that different steady states are reached after prolonged x-ray bombardment depending on the thickness of the HfO2 films. On the basis of the original work of Iwata et al. [J. App. Phys. 79, 6653 (1996)], a rigorous method to remove these artifacts and empirically determine the real band offsets in D/S heterojunctions is proposed and validated by comparison with internal photoemission and photoconductivity data obtained on the same set of samples.
Nonlinear thermal transport and negative differential thermal conductance in graphene nanoribbons
Authors: Hu Jiuning , Wang Yan , Vallabhaneni Ajit , Ruan Xiulin , Chen Yong P.
Published: September 2011

We employ classical molecular dynamics to study the nonlinear thermal transport in graphene nanoribbons (GNRs). For GNRs under large temperature biases beyond linear response regime, we have observed the onset of negative differential thermal conductance (NDTC). NDTC is tunable by varying the manner of applying the temperature biases. NDTC is reduced and eventually disappears when the length of the GNR increases. We have also observed NDTC in triangular GNRs, where NDTC exists only when the heat current is from the narrower to the wider end. These effects may be useful in nanoscale thermal managements and thermal signal processing utilizing GNRs.
Defect mediated optical emission of randomly oriented ZnO nanorods and unusual rectifying behavior of Schottky nanojunctions
Authors: Bayan Sayan , Mohanta Dambarudhar
Published: September 2011

We report on the interrelation of optical emission of randomly oriented ZnO nanorod system with the carrier transport properties of Ag/ZnO nanorod-based rectifying junctions. The ZnO nanorods, exhibiting a hexagonal wurtzite phase, were fabricated by a cost-effective rapid thermal annealing process and at different annealing temperatures. The photoluminescence spectra of the as grown samples have revealed various Zn and O related native defects (e.g., vacancies, interstitials etc.) located at ∼400, 428, 491, and 535 nm. As evident from the I-V characteristic curves, though all the Ag/ZnO nanojunctions show Schottky behavior, the nanorods grown at a temperature of 550 °C and 650 °C are characterized by very large ideality factors of respective values 35.4 and 33.2, apart from displaying unusually high reverse currents. Whereas, the samples grown at 450 °C and 750 °C show usual rectifying nature having relatively lower ideality factors (18.4 and 12.2), along with low leakage-current under reverse biasing. The enhancement or suppression of the reverse currents can be attributed to the eventual lowering or raising of the Schottky barrier heights which result from the variation in the native defect states of various ZnO nanorod systems. Correlating optical events and electrical response through native defects would find scope in assessing figure of merit and sensitivity while making rectifying nanojunctions and single electron devices.
Probing the aromaticity of the [(HtAc)3(μ2-H)6], [(HtTh)3(μ2-H)6],+, and [(HtPa)3(μ2-H)6] clusters
Authors: Ramírez-Tagle Rodrigo , Alvarado-Soto Leonor , Arratia-Perez Ramiro , Bast Radovan , Alvarez-Thon Luis
Published: September 2011

In this study we report about the aromaticity of the prototypical [(HtAc)3(μ2-H)6], [(HtTh)3(μ2-H)6]+, and [(HtPa)3(μ2-H)6] clusters via two magnetic criteria: nucleus-independent chemical shifts (NICS) and the magnetically induced current density. All-electron density functional theory calculations were carried out using the two-component zeroth-order regular approach and the four-component Dirac-Coulomb Hamiltonian, including scalar and spin-orbit relativistic effects. Four-component current density maps and the integration of induced ring-current susceptibilities clearly show that the clusters [(HtAc)3(μ2-H)6] and [(HtTh)3(μ2-H)6]+ are non-aromatic whereas [(HtPa)3(μ2-H)6] is anti-aromatic. However, for the thorium cluster we find a discrepancy between the current density plots and the classification through the NICS index. Our results also demonstrate the increasing influence of f orbitals, on bonding and magnetic properties, with increasing atomic number in these clusters. We think that the enhanced electron mobility in [(HtPa)3(μ2-H)6] is due the significant 5f character of its valence shell. Also the participation of f orbitals in bonding is the reason why the protactinium cluster has the shortest bond lengths of the three clusters. This study provides another example showing that the magnetically induced current density approach can give more reliable results than the NICS index.
Amplitude equations for breathing spiral waves in a forced reaction-diffusion system
Authors: Ghosh Pushpita , Ray Deb Shankar
Published: September 2011

Based on a multiple scale analysis of a forced reaction-diffusion system leading to amplitude equations, we explain the existence of spiral wave and its photo-induced spatiotemporal behavior in chlorine dioxide-iodine-malonic acid system. When the photo-illumination intensity is modulated, breathing of spiral is observed in which the period of breathing is identical to the period of forcing. We have also derived the condition for breakup and suppression of spiral wave by periodic illumination. The numerical simulations agree well with our analytical treatment.
Radiation patterns from coupled photonic crystal nanocavities
Authors: Brunstein M. , Karle T. J. , Sagnes I. , Raineri F. , Bloch J. , Halioua Y. , Beaudoin G. , Le Gratiet L. , Levenson J. A. , Yacomotti A. M.
Published: September 2011

We report on far field measurements on two coupled photonic crystal nanocavities. The distinct features of the antisymmetric modes (minima of intensity at zero-emission angles) allow us to demonstrate a π-phase difference between the cavity fields, a clear signature of evanescent coupling. Good agreement between experimental results and simulated radiation patterns has been found.
Optical-optical double resonance spectroscopy of the quasi-linear S2 state of CHF and CDF. I. Spectroscopic analysis
Authors: Tao Chong , Richmond Craig , Mukarakate Calvin , Dawes Richard , Kable Scott H. , Reid Scott A.
Published: September 2011

In this work, we report on our full results of the spectroscopic analysis of the quasi-linear S2 state of the prototypical halocarbene, CHF, and its deuterated isotopomer CDF using optical-optical double resonance spectroscopy through the S1 state. A total of 51 S2 state vibrational levels with angular momenta in the range ℓ = 0–3 were observed for CHF, and 76 levels for CDF. Progressions involving all three fundamental vibrations were observed, and rotational constants were determined for each of these levels by measuring spectra through different intermediate J levels of the S1 state. Our experimental results are in excellent agreement with the predictions of vibrational calculations using the discrete variable representation method. The variational vibrational calculations were performed with an analytic potential energy surface fit to ab initio data by the method of interpolating moving least squares. The ab initio data are Davidson-corrected multi-reference configuration interaction calculations based on a state-averaged multiconfigurational self-consistent field reference incorporating a generalized dynamic weighting scheme.
Atomic force microscopy at ambient and liquid conditions with stiff sensors and small amplitudes
Authors: Wutscher Elisabeth , Giessibl Franz J.
Published: September 2011

We report on atomic force microscopy (AFM) in ambient and liquid environments with the qPlus sensor, a force sensor based on a quartz tuning fork with an all-electrical deflection measurement scheme. Small amplitudes, stiff sensors with bulk diamond tips and high Q values in air and liquid allow to obtain high resolution images. The noise sources in air and liquid are analyzed and compared for standard silicon cantilevers and qPlus sensors. First, epitaxial graphene was imaged in air, showing atomic steps with 3 Å  height and ridges. As a second sample system, measurements on calcite (CaCO3) in liquids were performed in water and polyethylenglycol (PEG). We demonstrate high resolution images of steps in PEG on calcite and nanolithography processes, in particular with frequency-modulation AFM the controlled dissolution of calcite monolayers.
Experimental evidence of ferroelectric negative capacitance in nanoscale heterostructures
Authors: Islam Khan Asif , Bhowmik Debanjan , Yu Pu , Joo Kim Sung , Pan Xiaoqing , Ramesh Ramamoorthy , Salahuddin Sayeef
Published: September 2011

We report a proof-of-concept demonstration of negative capacitance effect in a nanoscale ferroelectric-dielectric heterostructure. In a bilayer of ferroelectric Pb(Zr0.2Ti0.8)O3 and dielectric SrTiO3, the composite capacitance was observed to be larger than the constituent SrTiO3 capacitance, indicating an effective negative capacitance of the constituent Pb(Zr0.2Ti0.8)O3 layer. Temperature is shown to be an effective tuning parameter for the ferroelectric negative capacitance and the degree of capacitance enhancement in the heterostructure. Landau’s mean field theory based calculations show qualitative agreement with observed effects. This work underpins the possibility that by replacing gate oxides by ferroelectrics in nanoscale transistors, the sub threshold slope can be lowered below the classical limit (60 mV/decade).
Electronic transport in single-walled carbon nanotube/graphene junction
Authors: Pei Tian , Xu Haitao , Zhang Zhiyong , Wang Zhenxing , Liu Yu , Li Yan , Wang Sheng , Peng Lian-Mao
Published: September 2011

Graphene/carbon nanotube (CNT) junctions were fabricated by depositing mechanically exfoliated graphene on substrate followed by direct chemical vapor deposition growth of CNT, and their electronic transport properties were investigated. Unlike metallic CNT/graphene junction with good contact, there exists an obvious Schottky barrier between semiconducting CNT and graphene due to the difference of their work functions, which lead to typical rectification properties and directionally field-effect behavior.
Communication: Stabilization of radical anions with weakly bound electron in condensed media: A case study of diacetonyl radical anion
Authors: Saenko Elizaveta V. , Laikov Dimitri N. , Baranova Irina A. , Feldman Vladimir I.
Published: September 2011

The radical anion resulting from electron capture by diacetonyl molecule has been characterized by EPR and optical absorption spectroscopy in glassy ether matrices at 77 K. In non-polar alkane glasses this species was not observed under the same conditions, which confirms the crucial role of matrix interactions in stabilizing this species. Calculations at the MP2 level show the vertical detachment energy to increase gradually from roughly zero for a bare anion to ∼1 eV for the complex involving six ether molecules.
Drinking behaviour of yellow-footed rock-wallabies (Petrogale xanthopus celeris) in semiarid Queensland
Authors: Sharp Andy
Published: September 2011

This study examined the patterns of water use by yellow-footed rock-wallabies (Petrogale xanthopus celeris) at a colony in semiarid Queensland. Visitation by wallabies to an earthen tank was monitored, over a three-year period, via radio-tracking. The rate of visitation to the tank was negatively linked to both rainfall in the previous month and rainfall during tracking, while being positively related to temperature. Drinking rate increased considerably when mean pasture moisture content fell below 20%. The regular visitation to the tank suggests that Queensland populations of wallabies may have a stronger reliance on free water than previously thought. The closure of artificial waters on conservation reserves and pastoral properties could result in dramatic declines in wallaby numbers and potentially localised extinctions.
Estimating brush-tailed rock-wallaby population size using individual animal recognition
Authors: Vernes Karl , Green Stuart , Thomas Piers
Published: September 2011

We undertook surveys of brush-tailed rock-wallabies (Petrogale penicillata) at four colonies in Oxley Wild Rivers National Park, north-eastern New South Wales, with the aim of developing a technique based upon individual animal recognition that could be used to obtain robust population estimates for rock-wallaby colonies. We identified individuals on the basis of distinct morphological characters in each colony using visual observations, and used the data within a ‘mark–recapture’ (or sight–resight) framework to estimate population size. More than 37 h of observations were made over 10 sampling days between 18 May and 9 June 2010. We could identify 91.7% of all rock-wallabies that were independently sighted (143 of 156 sightings of 35 animals). A small percentage of animals could not be identified during a visit because they were seen only fleetingly, were in dense cover, or were partly obscured by rock. The number of new animals sighted and photographed declined sharply at the midpoint of the survey, and there was a corresponding increase in resighting of known individuals. Population estimates using the mark–recapture methodology were nearly identical to estimates of total animals seen, suggesting that this method was successful in obtaining a complete census of rock-wallabies in each colony.
DNA ligand designed to antagonize EBNA1 represses Epstein–Barr virus‐induced immortalization
Authors: Yasuda Ai , Noguchi Kohji , Minoshima Masafumi , Kashiwazaki Gengo , Kanda Teru , Katayama Kazuhiro , Mitsuhashi Junko , Bando Toshikazu , Sugiyama Hiroshi , Sugimoto Yoshikazu
Published: September 2011

Epstein–Barr virus (EBV) transforms human B lymphocytes into immortalized cells in vitro and is associated with various malignancies in vivo. EBNA1, which is expressed in the majority of EBV‐infected cells, recognizes specific DNA sequences at the cis‐acting latent origin of plasmid replication (oriP) element of the EBV genome. EBNA1 plays a critical role in the viral episome maintenance and transactivates viral transforming genes in latently infected cells. Therefore, DNA‐targeting agents that can disrupt the EBNA1–oriP interaction will offer novel functional inhibitors of EBNA1. Pyrrole–imidazole polyamides, sequence‐specific DNA ligands, can be designed to interfere with the binding of various transcriptional factors. Here, we synthesized pyrrole–imidazole polyamides targeting EBNA1‐bound DNA sequences and developed an inhibitor for the EBNA1–oriP interaction. A pyrrole‐imidazole polyamide, designated as DSE‐3, bound adjacent to the EBNA1 recognition sequences located in the dyad symmetry element of oriP, and selectively inhibited EBNA1–oriP binding both in vitro and in vivo. DSE‐3 also inhibited the proliferation of established lymphoblastoid cell lines by eradicating EBV episomes from the cells. In addition, DSE‐3 repressed the expression of viral transforming genes after infecting human peripheral blood mononuclear cells with EBV and, as a consequence, inhibited EBV‐mediated B‐cell immortalization. These results suggest that EBNA1 functions will be an attractive pharmacological target for EBV‐associated diseases. (Cancer Sci 2011; 102: 2221–2230)
Four polymorphisms of the CAPN 10 gene and their relationship to polycystic ovary syndrome susceptibility: a meta‐analysis
Authors: Huang Miaoling , Xiao Jianpeng , Zhao Xiaomiao , Liu Changhao , Chen Qing
Published: September 2011

Objective  To investigate the association between CAPN 10 gene polymorphism and polycystic ovary syndrome (PCOS) susceptibility.

Design  Meta‐analysis of published case–control studies of four single nucleotide polymorphisms (SNPs) in CAPN 10 and PCOS susceptibility.

Patients  Women with PCOS.

Measurements  Odds ratios (ORs) and 95% confidence intervals (CIs) for heterozygous, homozygous, dominant model, recessive model and allele.

Results  A total of 11 studies were involved in the meta‐analysis. UCSNP‐63 was significantly associated with PCOS, with homozygous carriers (TT vs CC: OR = 0·64; 95% CI: 0·45–0·90) and recessive model (TT vs CC and CT: OR = 0·64; 95% CI: 0·45–0·90) being protective factors. In addition, UCSNP‐19 was significantly associated with PCOS, with recessive model (ins/ins vs del/del and del/ins: OR = 0·72, 95% CI: 0·59–0·88) and insert allele (ins vs del: OR = 0·85, 95% CI: 0·76–0·96) being protective factors, while heterozygous carriers (del/ins vs del/del: OR = 1·56, 95% CI: 1·24–1·94) and deletion allele (del vs ins: OR = 1·18, 95% CI: 1·04–1·32) being risk factors. However, no significant associations were found between UCSNP‐44, ‐43 and PCOS. Moreover, the results of the Rotterdam criteria subgroup analysis were similar with that of overall analysis.

Conclusions  This is the first report on the association between CAPN 10 UCSNP‐63 and PCOS in genotype, with homozygous carriers and recessive model being protective factors. Additionally, insert allele and recessive model of UCSNP‐19 are protective factors, while deletion allele and heterozygous genotype are risk factors for PCOS development.
Increased vitamin D supplementation recommended during summer season in the gulf region: a counterintuitive seasonal effect in vitamin D levels in adult, overweight and obese Middle Eastern residents
Authors: Al‐Daghri Nasser M. , Al‐Attas Omar S. , Alokail Majed S. , Alkharfy Khalid M. , El‐Kholie Emad , Yousef Mansour , Al‐Othman Abdulaziz , Al‐Saleh Yousef , Sabico Shaun , Kumar Sudhesh , Chrousos George P.
Published: September 2011

Purpose  Seasonal variations in circulating vitamin D levels provide vital information as to the most appropriate time to either start or increase vitamin D supplementation to maintain optimal vitamin D levels. In this follow‐up study, we determined seasonal differences in serum 25(OH)‐vitamin D (25(OH)D) levels, as well as parallel changes in metabolic parameters, in a cohort of adult, overweight and obese Saudis.

Methods  A total of 121 adult, overweight, obese, and consenting Saudis aged 18–70 years were randomly recruited from four Primary Health Care Centers in Riyadh, Saudi Arabia. They were divided according to the season when baseline measurements were made [74 summer (April–October); 47 winter (November–March)]. Anthropometrics were obtained, and fasting blood samples were taken at baseline and every 3 months for 1 year. Fasting blood glucose, corrected calcium levels, and lipid profiles were measured routinely. Serum 25(OH)‐vitamin D was quantified using a specific enzyme‐linked immunosorbent assay (ELISA).

Results  Age‐ and BMI‐matched mean 25(OH)‐vitamin D levels from the winter group were significantly higher than those of the summer group (P < 0·001). In both groups, HDL‐C levels improved significantly as 25(OH)‐vitamin D levels increased with subsequent follow‐ups, even after adjusting for age, gender and BMI (P < 0·001).

Conclusion  Seasonal differences in serum 25(OH)‐vitamin D levels in Saudi Arabia are counterintuitive, with circulating levels being higher during the winter than the summer season. Increased vitamin D supplementation is thus recommended to maintain optimal serum 25(OH)‐vitamin D levels during the summer season.
Resolving uncertainty and creating value from the exercise of e‐commerce investment options
Authors: Otim Sam , Grover Varun
Published: September 2011

This study examines the effect of the resolution of uncertainty on real options exercise decisions with respect to three e‐commerce investment options: scale‐up, stage and joint investment, and the relationship between exercise of these options and firm performance. The results of a study of 172 public e‐commerce investment announcements show that resolution of external (exogenous) and internal (endogenous) uncertainty has a significant effect on option exercise decisions. However, the results also imply that simply waiting without investment in active learning does not create significant value from real options. The key differentiator is how a firm resolves endogenous uncertainty as this endows it with the ability to successfully undertake the information technology investment and exploit the economic opportunity implied by the resolution of exogenous uncertainty. Furthermore, our results imply that different options should be used to manage situations involving certainty of loss on one hand and severity of loss on the other hand. Thus, it is important for firms to make the right choices when using options‐based investing to manage risk. We suggest that, perhaps, managers need to maintain a portfolio of options to manage the two dimensions of risk simultaneously.