bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of cardiac time intervals using high temporal resolution real‐time spiral phase contrast with UNFOLDed‐SENSE
Authors: Kowalik Grzegorz T. , Knight Daniel S. , Steeden Jennifer A. , Tann Oliver , Odille Freddy , Atkinson David , Taylor Andrew , Muthurangu Vivek
Published: February 2014

Purpose

To develop a real‐time phase contrast MR sequence with high enough temporal resolution to assess cardiac time intervals.

Methods

The sequence utilized spiral trajectories with an acquisition strategy that allowed a combination of temporal encoding (Unaliasing by fourier‐encoding the overlaps using the temporal dimension; UNFOLD) and parallel imaging (Sensitivity encoding; SENSE) to be used (UNFOLDed‐SENSE). An in silico experiment was performed to determine the optimum UNFOLD filter. In vitro experiments were carried out to validate the accuracy of time intervals calculation and peak mean velocity quantification. In addition, 15 healthy volunteers were imaged with the new sequence, and cardiac time intervals were compared to reference standard Doppler echocardiography measures. For comparison, in silico, in vitro, and in vivo experiments were also carried out using sliding window reconstructions.

Results

The in vitro experiments demonstrated good agreement between real‐time spiral UNFOLDed‐SENSE phase contrast MR and the reference standard measurements of velocity and time intervals. The protocol was successfully performed in all volunteers. Subsequent measurement of time intervals produced values in keeping with literature values and good agreement with the gold standard echocardiography. Importantly, the proposed UNFOLDed‐SENSE sequence outperformed the sliding window reconstructions.

Conclusion

Cardiac time intervals can be successfully assessed with UNFOLDed‐SENSE real‐time spiral phase contrast. Real‐time MR assessment of cardiac time intervals may be beneficial in assessment of patients with cardiac conditions such as diastolic dysfunction. Magn Reson Med 73:749–756, 2015. © 2014 Wiley Periodicals, Inc.
A novel computational approach for large deformation and post‐failure analyses of segmental retaining wall systems
Authors: Bui Ha H. , Kodikara Jayantha K. , Bouazza Abdelmalek , Haque Asadul , Ranjith Pathegama G.
Published: February 2014

Segmental retaining wall (SRW) systems are commonly used in geotechnical practice to stabilize cut and fill slopes. Because of their flexibility, these systems can tolerate minor movements and settlements without incurring damage or crack. Despite these advantages, very few numerical studies of large deformations and post‐failure behavior of SRW systems are found in the current literature. Traditional numerical methods, such as the finite element method, suffer from mesh entanglement, thus are unable to simulate large deformations and flexible behavior of retaining wall blocks in SRW systems. To overcome the above limitations, a novel computational framework based on the smoothed particle hydrodynamics (SPH) method was developed to simulate large deformations and post‐failure behavior of soils and retaining wall blocks in SRW systems. The proposed numerical framework is a hybrid continuum/discontinuum approach that can model soil as an elasto‐plastic material and retaining wall blocks as independent rigid bodies associated with both translational and rotational degrees of freedom. A new contact model is proposed within the SPH framework to simulate the interaction between the soil and the blocks and between the blocks. As an application of the proposed numerical method, a two‐dimensional simulation of an SRW collapse was simulated and compared to experimental results conducted under the same conditions. The results showed that the proposed computational approach provided satisfactory agreement with the experiment. This suggests that the new framework is a promising numerical approach to model SRW systems. Copyright © 2014 John Wiley & Sons, Ltd.
Constructing a strict total order for alternatives characterized by multiple criteria: An extension
Authors: Dehnokhalaji Akram , Korhonen Pekka J. , Köksalan Murat , Nasrabadi Nasim , Tezcaner Öztürk Diclehan , Wallenius Jyrki
Published: February 2014

The problem of finding a strict total order for a finite set of multiple criteria alternatives is considered. Our research extends previous work by us, which considered finding a partial order for a finite set of alternatives. We merge the preference information extracted from the preference cones and corresponding polyhedral sets, with the information derived from pairwise comparisons of two alternatives, yielding a preference matrix. This preference matrix is used as input to an integer programming model to obtain a strict total order that provides a transitive ranking for the set of alternatives. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 155–163, 2014
Modeling and analysis of exhaustive probabilistic search
Authors: Chung Timothy H. , Silvestrini Rachel T.
Published: February 2014

This article explores a probabilistic formulation for exhaustive search of a bounded area by a single searcher for a single static target. The searcher maintains an aggregate belief of the target's presence or absence in the search area, concluding with a positive or negative search decision on crossing of decision thresholds. The measure of search performance is defined as the expected time until a search decision is made as well as the probability of the search decision being correct. The searcher gathers observations using an imperfect detector, that is, one with false positive and negative errors, and integrates them in an iterative Bayesian manner. Analytic expressions for the Bayesian update recursion of the aggregate belief are given, with theoretical results describing the role of positive and negative detections, as well as sensitivity results for the effect of the detection errors on the aggregate belief evolution. Statistical studies via design of simulation experiments provide insights into the significant search parameters, including imperfect sensor characteristics, initial belief value, search decision threshold values, and the available prior probability information. Regression analysis yields statistical models to provide prescriptive guidance on the search performance as a function of these search parameters.Copyright © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 164–178, 2014
Bioreducible polyspermine as less toxic and efficient gene carrier
Authors: Park Hongsuk , Nichols Joseph W. , Kang Han Chang , Bae You Han
Published: February 2014

Bioreducible polymers have attracted intense attention as a gene carrier due to their low cell toxicity compared to other polymer‐based gene delivery counterparts. We have synthesized low‐molecular‐weight spermine‐originated bioreducible polyspermines (BPSs) to serve as a plasmid DNA (pDNA) carrier complex with low cytotoxicity and high transfection efficiency. Spermine is biogenic and ubiquitous and is of benefit to nucleic acid delivery in many respects. We found that the BPSs formed nano‐sized, positively charged complexes with pDNA. In addition, they showed a high buffering capacity from the polyamine‐based proton sponge effect which facilitates endosomal escape. With degradable characteristics in thiol‐rich (intracellular) environments, BPSs exhibited significantly improved cell viability and suitable transfection efficiency across several cell lines in comparison to linear and branched polyethylenimine, the current gold standards of non‐viral gene carriers. BPSs appear to be promising polymers for use as effective pDNA carriers. Copyright © 2014 John Wiley & Sons, Ltd.
Prognostic factors of Epstein–Barr virus‐associated hemophagocytic lymphohistiocytosis in children: Report of the Japan Histiocytosis Study Group
Authors: Kogawa Kazuhiro , Sato Hiroki , Asano Takeshi , Ohga Shouichi , Kudo Kazuko , Morimoto Akira , Ohta Shigeru , Wakiguchi Hiroshi , Kanegane Hirokazu , Oda Megumi , Ishii Eiichi
Published: February 2014

Background

Despite several advances in the treatment of Epstein–Barr virus (EBV) in recent years, patients with Epstein–Barr virus‐associated hemophagocytic lymphohistiocytosis (EBV‐HLH) do not always show satisfactory outcomes. We here conducted a nationwide survey in Japan to identify prognostic factors of EBV‐HLH in children with this disease in an effort to improve the management and the outcomes of these patients.

Procedure

Between January 2003 and June 2008, we enrolled 98 children younger than 18 years of age who were diagnosed with EBV‐HLH. We then studied the clinical characteristics and laboratory findings at the time of diagnosis with the aim to identify prognostic factors for EBV‐HLH.

Results

The mean age of onset of EBV‐HLH was 3.9 ± 2.8 years. Most of our patients presented with fever, hepatosplenomegaly, lymphadenopathy, and hemophagocytosis of bone marrow. Sixty‐two percent of patients showed T cell clonality, and 97% had EBV infection in either T or natural killer cells. Most patients (60%) were treated with a multi‐agent chemotherapeutic regimen, including corticosteroid, etoposide, and cyclosporine. After initial treatment, 90.3% of patients were in remission, and 7 patients (8.2%) experienced recurrence of EBV infection. Among several prognostic factors, patients with both hyperbilirubinemia (>1.8 mg/dl) and hyperferritinemia (>20,300 ng/ml) at the time of diagnosis had significantly poorer outcomes than those with low serum bilirubin and ferritin levels.

Conclusions

These findings suggest that the therapeutic strategy for children with EBV‐HLH could be tailored according to the laboratory findings at diagnosis. Pediatr Blood Cancer 2014;61:1257–1262. © 2014 Wiley Periodicals, Inc.
Study on the compatibility of ethylene‐vinyl acetate copolymer/vermiculite in biaxially oriented polypropylene films
Authors: Li Lidong , Xu Wencai , Qi Yingqun , Shang Wei , Fu Yabo , Liao Ruijuan
Published: February 2014

A process for preparing expanded vermiculite/ethylene vinyl acetate nanocomposites by ball milling expanded vermiculite (EVMT) in cyclohexane solution of ethylene vinyl acetate copolymer resin (EVA) was presented, and the influence of EVA/EVMT nanocomposites on mechanical, barrier performance of modified biaxially oriented polypropylene (BOPP) films was discussed in this article. By the process, the EVMT is intercalated and exfoliated to obtain a kind of EVMT/EVA nanocomposite, in which EVA serves as both intercalating agent into EVMT and compatibilizer between EVMT and polypropylene (PP); so, when EVMT/EVA was melt blended with PP, platelets of vermiculite can be exfoliated easily and dispersed relatively well in the PP matrix. Compared with original (nonmodified) BOPP, when EVMT loading ranged from 0.1% to 0.5%, both strength and toughness of the modified BOPP films was increased. Moreover, platelets (flakes) of vermiculite dispersed in PP matrix improved barrier properties of modified BOPP films also. The improved barrier properties of BOPP films accorded with Nielsen model. POLYM. COMPOS., 36:78–87, 2015. © 2014 Society of Plastics Engineers
Study on synthesis and application of collagen‐modified polylactic acid
Authors: Su Ruixia , Liu Leili , Li Xiao , Cui Miaomiao , Ma Feng
Published: February 2014

To modify the degradability and improve the hydrophilicity of polylactic acid (PLA), collagen‐modified polylactide (CPLA) was synthesized by means of grafting modification method including chloridization and aminolysis, and its structure was characterized by FTIR, 1H NMR, and fluorescein isothiocyanate‐labeled fluorescence spectra. Subsequently, the hydrophilicity and degradation behavior of CPLA were characterized. Finally, CPLA was used as a carrier for the preparation of the trypsin sustained release microspheres via the emulsion‐solvent evaporation technique, followed with its characterization. Results showed that the collagen had been grafted into PLA and the graft ratio of collagen measured about 6.7%. Water absorption behavior test indicated that the hydrophilicity of CPLA was significantly higher than PLA. Furthermore, degradability test revealed that the degradation behavior of PLA was obviously modified and there was no obvious acid‐catalyzed self‐accelerating degradation behavior in the degradation process of CPLA. It was also indicated that the encapsulation efficiency and drug content in trypsin‐loaded CPLA microspheres were all clearly higher than trypsin‐loaded PLA microspheres. The results suggested that CPLA showed a great potential as matrix for drug delivery. POLYM. COMPOS., 36:88–93, 2015. © 2014 Society of Plastics Engineers
Transposition of the great arteries: factors influencing prenatal diagnosis
Authors: Bertagna F. , Rakza T. , Vaksmann G. , Ramdane‐Sebbane N. , Devisme L. , Storme L. , Francart C. , Vaast P. , Houfflin‐Debarge V.
Published: February 2014

Objective

The objective of this study is to highlight the factors that may affect prenatal diagnosis of transposition of the great arteries (TGA) in order to improve it.

Methods

This is a retrospective study performed between 2004 and 2009 in the maternity units from North of France. We identified a total of 68 cases of TGA (isolated or associated with only VSD or coarctation of aorta), of which 32 (47.1%) had prenatal diagnosis (PND+) and 36 did not (PND−). Maternal characteristics and ultrasound factors were studied in relation to PND.

Results

Maternal weight and body mass index were significantly higher in the PND− group (70.4 kg and 26.5 kg/m2 vs 63.6 kg and 23.6 kg/m2, respectively). Maternal obesity (body mass index >30) was significantly more frequent in the PND− group (27.8% vs 12.5%). More than a quarter of TGA (28.1%) were diagnosed during the third trimester.

Conclusion

Obesity is the main cause of missed PND of TGA. Obese patients with suboptimal prenatal scans may benefit from reassessment of fetal cardiac anatomy and/or from referral for fetal echocardiography. © 2014 John Wiley & Sons, Ltd.
Highly conductive p  + + ‐AlGaAs/n  + + ‐GaInP tunnel junctions for ultra‐high concentrator solar cells
Authors: Barrigón Enrique , García Ivan , Barrutia Laura , Rey‐Stolle Ignacio , Algora Carlos
Published: February 2014

Tunnel junctions are key for developing multijunction solar cells (MJSC) for ultra‐high concentration applications. We have developed a highly conductive, high bandgap p  + + ‐AlGaAs/n  + + ‐GaInP tunnel junction with a peak tunneling current density for as‐grown and thermal annealed devices of 996 A/cm 2 and 235 A/cm 2, respectively. The J–V characteristics of the tunnel junction after thermal annealing, together with its behavior at MJSCs typical operation temperatures, indicate that this tunnel junction is a suitable candidate for ultra‐high concentrator MJSC designs. The benefits of the optical transparency are also assessed for a lattice‐matched GaInP/GaInAs/Ge triple junction solar cell, yielding a current density increase in the middle cell of 0.506 mA/cm 2 with respect to previous designs. Copyright © 2014 John Wiley & Sons, Ltd.
Suspension trapping (STrap) sample preparation method for bottom‐up proteomics analysis
Authors: Zougman Alexandre , Selby Peter J. , Banks Rosamonde E.
Published: February 2014

Despite recent developments in bottom‐up proteomics, the need still exists in a fast, uncomplicated, and robust method for comprehensive sample processing especially when applied to low protein amounts. The suspension trapping method combines the advantage of efficient SDS‐based protein extraction with rapid detergent removal, reactor‐type protein digestion, and peptide cleanup. Proteins are solubilized in SDS. The sample is acidified and introduced into the suspension trapping tip incorporating the depth filter and hydrophobic compartments, filled with the neutral pH methanolic solution. The instantly formed fine protein suspension is trapped in the depth filter stack—this crucial step is aimed at separating the particulate matter in space. SDS and other contaminants are removed in the flow‐through, and a protease is introduced. Following the digestion, the peptides are cleaned up using the tip's hydrophobic part. The methodology allows processing of protein loads down to the low microgram/submicrogram levels. The detergent removal takes about 5 min, whereas the tryptic proteolysis of a cellular lysate is complete in as little as 30 min. We have successfully utilized the method for analysis of cellular lysates, enriched membrane preparations, and immunoprecipitates. We expect that due to its robustness and simplicity, the method will become an essential proteomics tool.
Novel alkoxyanthracene donor and benzothiadiazole acceptor for organic thin film transistor and bulk heterojunction organic photovoltaic cells
Authors: Ma Jae Yeol , Yun Hui‐Jun , Kim Seul‐Ong , Lee Gi Back , Cha Hyojung , Park Chan Eon , Kwon Soon‐Ki , Kim Yun‐Hi
Published: February 2014

Novel alkoxy anthracene (ODA)‐based polymeric semiconductors were designed for polymer solar cell applications. Alkoxyanthracene, which contains many π electrons and electron donating group, was easily synthesized. The copolymers, poly(alkoxy anthracene‐alt‐thiophene benzothiadiazole thiophene) poly(ODA‐TBT) and poly(alkoxy anthracene‐alt‐benzothiadiazole) poly(ODA‐BT), have been obtained by Suzuki coupling polymerization. Both polymers have ODA unit as a donor and benzothiadiazole as an acceptor. ODA‐TBT has thiophene linkages between ODA and benzothiadiazole. The optical, thermal, and electrochemical properties have been investigated by UV–visible absorption, thermal gravimetric analysis, differential scanning calorimetry, and CV. Organic thin‐film transistor using polymers showed that the hole mobility of poly(ODA‐alt‐TBT) was around 3.6 × 10−3 cm2/Vs with on/off ratio of 9.91 × 105 while that of poly(ODA‐alt‐BT) was around 1.21 × 10−2 cm2/Vs with on/off ratio of 2.64 × 106. Organic photovoltaic performance based on polymers were evaluated with a configuration of ITO/PEDOT:PSS/active layer/LiF/Al. Poly(ODA‐TBT) exhibits a short circuit current (Jsc) of 3.9 mA/cm2 and power conversion efficiency (PCE) of 1.4%, and poly(ODA‐BT) exhibits the Jsc of 6.4 mA/cm2 and PCE of 2.2%. The better device performance of poly(ODA‐BT) is attributed to its charge transfer ability and enhanced mobility and crystallinity although poly(ODA‐BT) does not have extended π‐conjugation due to twisted structure compared with poly(ODA‐TBT). © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1306–1314
Living and stereoselective polymerization of rac‐lactide by bimetallic aluminum Schiff‐Base complexes
Authors: Qu Zhi , Duan Ranlong , Pang Xuan , Gao Bo , Li Xiang , Tang Zhaohui , Wang Xianhong , Chen Xuesi
Published: February 2014

A series of bimetallic aluminum Schiff‐base complexes have been prepared and characterized. The complexes used as catalysts were applied in the lactide polymerization to test their activities and stereoselectivities. All polymerizations are living, as evidenced by the narrow polydispersities and the good fit between calculated and found number‐average molecular weights of the isolated polymers. Isotactic enriched polylactide was obtained by using these complexes. Kinetic studies indicated that the polymerizations are both first‐ordered with respect to lactide monomer and catalyst. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1344–1352
Self‐consistent field theory investigation of directed self‐assembly in cylindrical confinement
Authors: Laachi Nabil , Delaney Kris T. , Kim Bongkeun , Hur Su‐Mi , Bristol Robert , Shykind David , Weinheimer Corey J. , Fredrickson Glenn H.
Published: February 2014

We use self‐consistent field theory to study the self‐assembly of cylinder‐forming diblock copolymers confined in a cylindrical prepattern. This situation arises in contact holes—the hole shrink problem—where the goal is to produce a cylindrical hole with reduced dimensions relative to a guiding prepattern. In this study, we focus on systems with a critical prepattern dimension ranging from 50 nm to 100 nm that consequently lead to the formation of a single cylinder in the middle of the hole. We find that a variety of defect morphologies arise from the self‐assembly process and are strongly governed by the prepattern dimensions, wetting conditions as well as the polymer molecular weight. We also consider blends of diblock copolymers and homopolymers and determine optimal blending configurations that not only favor the formation of the desired cylindrical morphology but also extend the processing window relative to the pure diblock case. When defective structures form inside the prepattern, we compute their formation energy and use the string method to examine the kinetic pathways for the transition from the defective state to the perfect cylindrical state. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015, 53, 142–153
Multilayer films composed of conductive poly(3‐hydroxybutyrate)/carbon nanotubes bionanocomposites and a photoresponsive conducting polymer
Authors: Valentini Luca , Fabbri Paola , Messori Massimo , Degli Esposti Micaela , Bittolo Bon Silvia
Published: February 2014

In order to develop new electronic devices, it is necessary to find innovative solutions to the eco‐sustainability problem of materials as substrates for circuits. We realized a photoresponsive device consisting of a semiconducting polymer film deposited onto optically semitransparent and conductive biodegradable poly(3‐hydroxybutyrate) (PHB)/carbon nanotube (CNT) substrates. The experiments indicated that the PHB‐CNT bionanocomposite substrate behaves as an optical window trapping electric charges produced by the photoexcitation of the semiconducting polymer. Such PHB‐CNT functional substrates are expected to be attractive for eco‐friendly electronics. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 596–602
Characterising Runoff Generation Processes in a Lake‐Rich Thermokarst Landscape (Old Crow Flats, Yukon, Canada) using δ18O, δ2H and d‐excess Measurements
Authors: Turner Kevin W. , Edwards Thomas W. D. , Wolfe Brent B.
Published: February 2014

Application of novel hydrological methods for assessing runoff generation in remote northern landscapes is necessary to identify the consequences of climate variability and change. In Old Crow Flats, a lake‐rich thermokarst landscape in northern Yukon Territory (Canada), local land users have concerns over the effects of recent lake drainage and fluctuating river discharge on their traditional way of life. In the absence of hydrometric stations, we evaluate the utility of isotopic monitoring of the lower Old Crow River, which is fed by several tributaries and drains the flats, for tracking runoff generation. Isotopic ‘snapshots’ obtained from 2007, 2008 and 2009 during the recession limb of the spring freshet hydrograph provided characteristic patterns of deuterium excess (d‐excess) along the Old Crow River. River sampling in June 2007 captured a pulse of evaporatively enriched lake water originating from a rainfall‐triggered catastrophic lake drainage event, identified by decreased d‐excess values. June 2008 was marked by negligible variability in d‐excess values along the same reach of the river, consistent with minimal export of lake waters after a winter of below‐normal snow accumulation. In contrast, rising d‐excess values along the study reach in June 2009 indicate enhanced rainfall‐generated runoff. River isotope sampling could be used to monitor spatial and temporal variability in runoff generation processes in the Old Crow Flats and other northern lake‐rich landscapes drained by rivers. Copyright © 2014 John Wiley & Sons, Ltd.
Cystic Fibrosis Database (CFDB): A new web‐based tool for cystic fibrosis specialists
Authors: Buzzetti Roberto , Cirilli Natalia , Minicucci Laura , Raia Valeria , Salvatore Donatello , Maffeis Paolo
Published: February 2014

In order to help specialists involved in CF care and clinical research to know the current best evidence about clinical effectiveness of interventions in CF, we designed and developed a web‐based, free access tool called “CFDB”—Cystic Fibrosis DataBase (www.inetflow.it/CFDB). The database was built by searching in Medline, Embase, Cochrane Library and worldwide trials registries all studies involving clinical interventions in CF. The tool lets the user define queries starting from one or more types of pathological conditions and one or more interventions. The output of the queries is structured in three levels: (1) how many and which studies deal with the conditions formulated in the query; (2) which are the main results of these studies; (3) a critical summary of the literature related to the query. This tool, providing a quick overview of the available evidence in clinical research in CF, may help clinical decision making, designing of new trials and building guidelines. Pediatr Pulmonol. 2014; 49:938–940. © 2014 Wiley Periodicals, Inc.
The bronchodilator response as a predictor of inhaled corticosteroid responsiveness in asthmatic children with normal baseline spirometry
Authors: Galant Stanley P. , Morphew Tricia , Guijon Olga , Pham Linh
Published: February 2014

Rationale

Although inhaled corticosteroids (ICS) are considered first line controller therapy in children with persistent asthma, heterogeneity of the ICS response can be an important clinical problem. The purpose of this study is to determine the value of the bronchodilator response (BDR) in identifying the ICS responder and establish the optimal BDR cut‐point that could be particularly useful in the clinic setting when baseline spirometry is normal.

Methods

Mexican American asthmatic children, 5–18 years, with normal baseline spirometry who required low dose (step 2), or medium dose (step 3) ICS therapy were evaluated by skin prick test for atopy, and pre‐ and post‐bronchodilator spirometry. ICS responders were defined by a ≥7.5% improvement in the FEV1 following 4–6 weeks of therapy. The optimal cut‐point was determined by Receiver Operator Characteristic (ROC) curves as the best balance between sensitivity and specificity.

Results

There were 34.8% of the 132 study patients who were ICS responders. ROC curves showed the BDR ≥10% to be an optimal cut‐point with sensitivity 46%, specificity 76%, positive predictive value (PPV) 50%, and negative predictive value (NPV) 72%. Atopic females with a BDR ≥10% had a PPV of 73%.

Conclusions

The composite phenotype of female gender, atopic, and the BDR of ≥10% identified 73% as ICS responders compared to 50% in our overall population with a BDR of ≥10% alone, with minimal false positives. We suggest that the BDR in conjunction with gender and atopic status be considered as potentially useful predictors of the ICS responder, particularly when baseline spirometry is normal. Pediatr Pulmonol. 2014; 49:1162–1169. © 2014 Wiley Periodicals, Inc.
Proteomic and other analyses to determine the functional consequences of deregulated kallikrein‐related peptidase (KLK) expression in prostate and ovarian cancer
Authors: Fuhrman‐Luck Ruth Anna , Silva Munasinghage Lakmali , Dong Ying , Irving‐Rodgers Helen , Stoll Thomas , Hastie Marcus Lachlan , Loessner Daniela , Gorman Jeffrey John , Clements Judith Ann
Published: February 2014

Rapidly developing proteomic tools are improving detection of deregulated kallikrein‐related peptidase (KLK) expression, at the protein level, in prostate and ovarian cancer, as well as facilitating the determination of functional consequences downstream. MS‐driven proteomics uniquely allows for the detection, identification, and quantification of thousands of proteins in a complex protein pool, and this has served to identify certain KLKs as biomarkers for these diseases. In this review, we describe applications of this technology in KLK biomarker discovery and elucidate MS‐based techniques that have been used for unbiased, global screening of KLK substrates within complex protein pools. Although MS‐based KLK degradomic studies are limited to date, they helped to discover an array of novel KLK substrates. Substrates identified by MS‐based degradomics are reported with improved confidence over those determined by incubating a purified or recombinant substrate and protease of interest, in vitro. We propose that these novel proteomic approaches represent the way forward for KLK research, in order to correlate proteolysis of biological substrates with tissue‐related consequences, toward clinical targeting of KLK expression and function for cancer diagnosis, prognosis, and therapies.
THz intersubband transitions in AlGaN/GaN multi‐quantum‐wells
Authors: Beeler Mark , Bougerol Catherine , Bellet‐Amalaric Edith , Monroy Eva
Published: February 2014

Various designs of AlGaN/GaN structures displaying intersubband absorption in the THz spectral range are reported upon. Firstly, samples with 3‐layer quantum wells (step‐quantum‐wells) displaying far‐infrared intersubband absorption are presented. Theoretical analysis of the reproducibility issues associated to this architecture is done, and a more robust design based on 4‐layer quantum wells is proposed. Such a structure has been fabricated by plasma‐assisted molecular‐beam epitaxy using two Al effusion cells to produce three AlGaN concentrations, without growth interruptions. Samples have been structurally validated by transmission electron microscopy and X‐ray diffraction. Fourier transform infrared spectroscopy measurements show far‐infrared absorption of TM‐polarized light, which gets broader and deeper for increasing doping levels.
75As NQR signature of the isoelectronic nature of ruthenium for iron substitution in LaFeRuAsO
Authors: Mazzani Marcello , Bonfà Pietro , Allodi Giuseppe , Sanna Samuele , Martinelli Alberto , Palenzona Andrea , Manfrinetti Pietro , Putti Marina , De Renzi Roberto
Published: February 2014

We have investigated the effects of the isovalent ruthenium substitution in LaFeRuAsO, by extensive 75As NQR (nuclear quadrupole resonance) measurements, supported by DFT (density functional theory) calculations, in order to characterize both the lattice and electronic structure details. The evidence for five different local configurations around the arsenic site emerges upon increasing ruthenium for iron substitution. DFT calculations confirm the attribution of the measured electric field gradients (EFGs) to ruthenium atom occupancies (0, 1, 2, 3, and 4) on the nearest‐neighbour sites of arsenic. It is found that the low‐frequency (Ru‐free) NQR peak remains almost unaffected upon ruthenium substitution, providing an experimental confirmation that ruthenium does not introduce delocalized carriers in the iron plane.
Enhanced Debye level in nano , , and NiSb: Nuclear inelastic spectroscopy on121 Sb
Authors: Claudio Tania , Bessas Dimitrios , Birkel Christina S. , Kieslich Gregor , Panthöfer Martin , Sergueev Ilya , Tremel Wolfgang , Hermann Raphael P.
Published: February 2014

The121 Sb partial density of phonon states (DPS) in nanopowder antimonides were obtained with nuclear inelastic scattering on , , and NiSb prepared by a wet chemistry route. The DPS is compared with the bulk counterpart. An increase of the Debye level indicative of a decrease of the isothermal speed of sound is systematically observed. This observation reveals that the decrease in speed of sound observed in nanostructured thermoelectric materials is not restricted to sintered nanocomposites.
Spin entanglement generation and detection in semiconductor nanostructures
Authors: Belzig Wolfgang , Bednorz Adam
Published: February 2014

Entanglement, viz. the non‐separability of quantum states, is a fundamental prediction of quantum mechanics, which is at odds with the classical perception of reality. Furthermore, it constitutes a resource for quantum computation and quantum communication. Electronic degrees of freedom in nanostructures –in particular the spin –constitute promising candidates to implement quantum information architectures in scalable solid state circuits. In this topical review, we will summarize some efforts to create and detect entanglement in such structures. We concentrate first on entanglement in double quantum dots, since they promise to be viable candidates to produce entanglement by confining electrons to a small interaction region. The quantitative detection of the entanglement through transport measurements can be done via current and noise. Secondly, we concentrate on the creation of spin entanglement at quantum point contacts, which has the advantage that the two electrons are automatically spatially separated. We discuss the possibility of performing a Bell test of non‐local correlations. However, as we will point out, a reliable entanglement detection can be performed by current‐correlation measurements, although they require some trust in the experimental setup. Finally, we present a hierarchy of mesoscopic Bell tests, which could be useful to evaluate theoretical proposals and experimental setups.
Self‐aligned gate‐last enhancement‐ and depletion‐mode AlN/GaN MOSHEMTs on Si
Authors: Huang Tongde , Ma Jun , Lu Xing , Liu Zhao Jun , Zhu Xueliang , Lau Kei May
Published: February 2014

This paper demonstrates the fabrication of self‐aligned gate‐last enhancement‐ and depletion‐mode (E/D‐mode) AlN/GaN metal‐oxide‐semiconductor high‐electron‐mobility‐transistors (MOSHEMTs). In addition, the effects of annealing on threshold voltage (Vth) are analyzed. The E and D‐mode transistors were fabricated with Ni/Au and Ti/Au as the gate metal, respectively. The Ni/Au gated MOSHEMTs show Vth = +0.3 V after post‐gate metallization annealing, and the Ti/Au gated MOSHEMTs without annealing show Vth= ‐1.8 V. In the E‐mode (Ni/Au gated) transistors, the Vth shift after post‐gate annealing is due to the decrease of fixed charges at the Al2O3/GaN interface. An investigation has been conducted for the understanding of the Vth shift, which is crucial for improving the transistors' stability in various applications. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐efficiency blue and green LEDs grown on Si with 5 micrometer thick GaN buffer
Authors: Zou Xinbo , Wong Ka Ming , Chong Wing Cheung , Ma Jun , Lau Kei May
Published: February 2014

High‐efficiency blue and green light‐emitting diodes (LEDs) were grown on planar Si substrates using a 5 µm thick GaN buffer by metalorganic chemical vapor deposition (MOCVD). AlN/GaN superlattices (SLs)–based interlayers were inserted twice for stress balancing and dislocation reduction. Smooth surface and low dislocation density of 1 × 109 cm–2 were achieved. The light output power (LOP) of bare 300 × 300 µm2 447 nm–LEDs and 510 nm–LEDs on Si was measured to be 2.15 mW and 0.85 mW at 20 mA, respectively. At –15 V, leakage current of as low as 3 µA was achieved for 447 nm–LEDs while higher leakage current was measured for green LEDs. After Si substrate removal, the LOP of packaged 440 nm– and 500 nm–LEDs reached 8.50 mW and 4.85 mW at 20 mA, respectively. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of semipolar {11$ \bar 2 $2} light‐emitting diodes using a hole blocking layer
Authors: Nakao Kota , Haziq Muhammad , Okamura Yasumasa , Yamane Keisuke , Okada Narihito , Tadatomo Kazuyuki
Published: February 2014

In this study, we fabricated {11$ \bar 2 $2} light‐emitting diodes (LEDs) using a single quantum well (SQW) and hole blocking layer (HBL) with various Al compositions and investigated the effect of the HBL on the characteristics of the LED. The electroluminescence (EL) intensity increased with an increase of the Al composition of the HBL. Furthermore, the EL intensity increased by a factor of six when the Al composition of the HBL increased by 25%. The forward voltages of the LEDs with the HBLwere approximately 3 V regardless of the Al composition of the HBL. The prevention of hole overflow using the HBL is demonstrated by the injection current dependence of the EL intensity and the blueshift by comparing the SQW LEDs with the HBLs with the SQW LEDs without the HBL and a multiple quantum well LED. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Non‐polar (11$ \bar 2 $0) InGaN quantum dots with short exciton lifetimes grown by metal‐organic vapour phase epitaxy
Authors: Emery Robert M. , Zhu Tongtong , Oehler Fabrice , Reid Benjamin , Taylor Robert A. , Kappers Menno J. , Oliver Rachel A.
Published: February 2014

InGaN quantum dot (QD) structures have been grown by metal organic vapour phase epitaxy (MOVPE) on non‐polar (11‐20) GaN surfaces by employing an anneal step in nitrogen immediately after the growth of the InGaN. Here, we compare the growth of such structures on pseudo‐substrates grown using an epitaxial lateral overgrowth (ELOG) technique and on pseudo‐substrates grown using a simpler in situ SiNx interlayer. The less complex defect reduction approach results in a significantly higher defect density, but does not detrimentally effect the QD formation. For both types of pseudo‐substrate, sharp peaks with resolution limited widths are observed in both cathodoluminescence at 9 K and micro‐photoluminescence at 4.2 K. The QDs demonstrate significantly reduced exciton lifetimes compared to structures grown on c‐plane, which has advantages for possible applications in single photon sources. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
GaN tubes with coaxial non‐ and semipolar GaInN quantum wells
Authors: Heinz Dominik , Fikry Mohamed , Aschenbrenner Timo , Schowalter Marco , Meisch Tobias , Madel Manfred , Huber Florian , Hocker Matthias , Frey Manuel , Tischer Ingo , Neuschl Benjamin , Mehrtens Thorsten , Müller Knut , Rosenauer Andreas , Hommel Detlef , Thonke Klaus , Scholz Ferdinand
Published: February 2014

We present the position‐controlled growth of GaN nanotubes with coaxial GaInN quantum wells by using ZnO nanowires grown on top of GaN pyramids as templates. High resolution scanning transmission electron microscopy allows us to perform a detailed structural analysis of individual tubes. In particular, we report about structural properties like indium incorporation, thickness, and homogeneity of quantum wells realized on nonpolar m‐plane side facets or on semipolar tips. Additionally, high resolution spatially and spectrally resolved cathodoluminescence spectroscopy performed at low temperature enables us to clearly identify the quantum well luminescence contributions for different kinds of facets on a single tube. The luminescence of the quantum wells deposited at variable temperatures shows a clear spectral shift in the cathodoluminescence signal, yielding an activation energy for the indium desorption from the m‐plane side facets of about 1.6 eV. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
GaN‐on‐Si wafers for HEMTs with high power‐driving capability
Authors: Hu Cheng‐Yu , Murad Saad , Nishikawa Atsushi , Groh Lars , Pinos Andrea , Tan Weisin , Chitnis Ashay , Sizov Victor , Yagi Takuma , Lutgen Stephan
Published: February 2014

By means of our patented strain engineering technology, we achieved high crystal quality and near zero wafer bow on our 150 mm GaN‐on‐Si wafers. To show the feasibility of our wafers for HEMTs with large gate periphery, we investigated the buffer breakdown(VBR) yield on device test structures with different periphery. To reduce the processing complexity, we used comb‐shaped structures with only source and drain contacts and N+ implant isolation in between the contacts. The VBR was defined at buffer leakage of 1 µA/mm. For a typical source‐drain distance of 14 µm, the VBR yield specification is 600 V. Then we demonstrated over 80% VBR yield for 100 mm device test structures on our 150 mm GaN‐on‐Si wafers. This high yield for large periphery test structures shows that our 150 mm GaN‐on‐Si wafers are very suitable for fabricating large HEMT devices. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of thermoelectric properties of GaN and ZnO samples
Authors: Kucukgok B. , Wang B. , Melton A. G. , Lu N. , Ferguson I. T.
Published: February 2014

In this paper, room temperature thermoelectric (TE) properties of wide bandgap thin film GaN and bulk ZnO are studied. Bulk GaN is also incorporated with epitaxy films to make comparison. GaN and ZnO materials have superior electrical performance and chemical stability at high temperatures and are currently found in many commercial applications, such as, photovoltaic, solid‐state lighting, and gas sensors. Since there are not many semiconductor materials that can operate effectively at high temperatures, wide bandgap materials like GaN and ZnO would be a promising solution for high temperatures thermoelectric power generation. In order to understand their TE properties, we systematically compared and characterized TE behaviour of GaN and ZnO thin films with a function of doping concentrations. The common trend of a decrease in Seebeck coefficients with the increase of carrier concentration for thin film and bulk GaN is observed, however, reverse TE trend for bulk ZnO, were observed. The most commonly observed TE trend is attributed to Mott‐Jones relation to simple transport models while inverse trend could be suggested as hopping conductance. Moreover, the Seebeck coefficients of ZnO samples are found to be larger than those of thin film and bulk GaN samples in the similar carrier density. Highest power factors, 2.6×10–4 W/mK2and 0.65×10–4 W/mK2, and Seebeck coefficients, 478 µV/K and 481 μV/K were measured for thin film GaN and bulk ZnO, respectively. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Flash MOS‐HFET operational stability for power converter circuits
Authors: Kirkpatrick Casey , Lee Bongmook , Ramanan Narayanan , Misra Veena
Published: February 2014

The enhancement mode metal oxide semiconductor heterojuntion field effect transistor with a flash gate stack (Flash MOS‐HFET) device structure is demonstrated as the switching device in a boost converter circuit operating at 1 MHz. The Flash MOS‐HFET device maintains a constant threshold voltage for the duration of circuit operation at temperatures up to 125 °C. This is the first report of Flash MOS‐HFET operation at high temperature without charge loss over time resulting in negative threshold voltage shift. The Flash MOS‐HFET structure therefore is not limited by charge loss and can be inserted into power electronic device circuits as a traditional enhancement mode device. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
InN quantum dots on GaN nanowires grown by MOVPE
Authors: Bi Zhaoxia , Lindgren David , Johansson B. Jonas , Ek Martin , Wallenberg L. Reine , Gustafsson Anders , Borgström Magnus T , Ohlsson Jonas , Monemar Bo , Samuelson Lars
Published: February 2014

In this work, growth of InN quantum dots (QDs) on GaN nanowires (NWs) by metal‐organic vapour phase epitaxy is demonstrated, illustrating the feasibility to combine 0D and 1D structures for nitride semiconductors. Selective area growth was used to generate arrays of c‐oriented GaN NWs using Si3N4 as the mask material. In general, InN QDs tend to form at the NW edges between the m‐plane side facets, but the QD growth can also be tuned to the side facets by controlling the growth temperature and the growth rate. TEM characterization reveals that I1‐type stacking faults are formed in the QDs and originate from the misfit dislocations at the InN/GaN interface. Photoluminescence measurement at 4 K shows that the peak shifts to high energy with reduced dot size. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermoelectric properties of unoxidized graphene/Bi2Te2.7Se0.3 composites synthesized by exfoliation/re‐assembly method
Authors: Kim Jin Il , Lee Eun Sil , Kim Jong‐Young , Choi Soon‐Mok , Lee Kyu Hyoung , Seo Won‐Seon
Published: February 2014

Nanocomposites of n‐type thermoelectric Bi2Te2.7Se0.3 (BTS) and unoxidized graphene (UG) were prepared from the exfoliated BTS and UG nanoplatelets. Polycrystalline BTS ingots were exfoliated into nanoscoll‐type crystals by chemical exfoliation, and were re‐assembled with UG nanoplatelets. The composites were chemically reduced by hydrazine hydrate and sintered by a spark‐plasma‐sintering method. The thermoelectric properties of the sintered composites were evaluated and exhibited decreased carrier concentration and increased thermal conductivity due to the embedded graphene. The peak ZT values for the UG/BTS‐US and UG/BTS‐EX composites were ∼0.8 at the UG concentration of 0.05 wt%. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Solid‐phase epitaxy of InOx Ny alloys via thermal oxidation of InN films on yttria‐stabilized zirconia
Authors: Kobayashi Atsushi , Itoh Takeki , Ohta Jitsuo , Oshima Masaharu , Fujioka Hiroshi
Published: February 2014

The characteristics of InOx Ny alloy films prepared via thermal oxidation of InN epitaxial films with In‐ or N‐polarities grown on nearly lattice‐matched, yttria‐stabilized zirconia (YSZ) substrates are investigated. The InN films were oxidized to InOx Ny with a gradual change in O/N composition by annealing in air. Structural analysis revealed that the temperature for phase transition from wurtzite structure depends on the polarity of InN, and N‐polar InOx Ny films can retain their wurtzite structure even at higher temperatures compared with the case of In‐polar films. Furthermore, changes in the valence band structure and optical characteristics of the InOx Ny alloys take place via thermal oxidation. These results indicate that InOx Ny grown via thermal oxidation of N‐polar InN on YSZ can be considered as an alloy semiconductor for optoelectronic devices. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental, thermodynamic and quantum chemical studies on adsorption and corrosion inhibition performance of synthesized pyridine derivatives on N80 steel in HCl solution
Authors: Yadav Mahendra , Kumar Sumit
Published: February 2014

The corrosion inhibition properties of synthesized pyridine derivatives, namely, 4‐(4‐methoxyphenyl)‐5,6‐dimethyl‐2‐morpholinopyridine‐3‐carbonitrile and 4‐(4‐methoxyphenyl)‐5,6‐dimethyl‐2‐piperazinyl‐pyridine‐3‐carbonitrile on N80 steel in 15% HCl solution were studied using gravimetric measurement, potentiodynamic polarization and electrochemical impedance spectroscopy techniques. The inhibition efficiency was found to increase with increasing inhibitor concentration and decreases on increasing the temperature from 303 to 333K. Some thermodynamic and kinetic parameters were calculated and discussed. The adsorption of inhibitor on the N80 steel surface obeys the Langmuir adsorption isotherm. Polarization studies showed that both the inhibitors behave as a mixed‐type inhibitor. Scanning electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy and atomic force microscopy were performed for the surface study of uninhibited and inhibited N80 steel samples. The density functional theory was employed for theoretical calculations. Copyright © 2014 John Wiley & Sons, Ltd.
Contribution of elastic photoelectron scattering to the shape of the measured XPS intensity in‐depth profile
Authors: Zommer L. , Lisowski W. , Jablonski A.
Published: February 2014

The in‐depth profiles obtained from Auger electron spectroscopy or X‐ray photoelectron spectroscopy (XPS) experiments are known to differ from an actual concentration profiles due to limitations of surface‐sensitive techniques, e.g. finite sampling depth, or atomic mixing during sputtering. However, the monitored signal intensities are also affected by elastic scattering of signal electrons. Calculations performed for idealized multilayer structures indicate that elastic scattering of photoelectrons may significantly influence the in‐depth signal intensity. In the present work, an attempt is made to evaluate the contribution of elastic photoelectron scattering to measured signal intensity profile for samples with diffused interfaces. The in‐depth profile measured for the 5x(Au/Ni)/Si multilayer structure has been submitted to this analysis. A relatively simple procedure to evaluate the contribution of elastic scattering to the profile shape has been proposed. The effect of elastic scattering is found to be a reduction of the XPS intensity by 5–10% in the investigated cases. Copyright © 2014 John Wiley & Sons, Ltd.