bluuebunny/crossref_metadata_2025 huggingface dataset:
Voluntary organ donation system adapted to Chinese cultural values and social reality
Authors: Huang Jiefu , Millis J. Michael , Mao Yilei , Millis M. Andrew , Sang Xinting , Zhong Shouxian
Published: December 2014

Organ donation and transplant systems have unique characteristics based on the local culture and socioeconomic context. China's transplant and organ donation systems developed without regulatory oversight until 2006 when regulation and policy were developed and then implemented over the next several years. Most recently, the pilot project of establishing a voluntary citizen‐based deceased donor program was established. The pilot program addressed the legal, financial, and cultural barriers to organ donation in China. The pilot program has evolved into a national program. Significantly, it established a uniquely Chinese donor classification system. The Chinese donor classification system recognizes donation after brain death (category I), donation after circulatory death (category II), and donation after brain death followed by circulatory death (category III). Through August 2014, the system has identified 2326 donors and provided 6416 organs that have been allocated though a transparent organ allocation system. The estimated number of donors in 2014 is 1147. As China's attitudes toward organ donation have matured and evolved and as China, as a nation, is taking its place on the world stage, it is recognizing that its past practice of using organs from executed prisoners is not sustainable. It is time to recognize that the efforts to regulate transplantation and provide voluntary citizen‐based deceased organ donation have been successful and that China should use this system to provide organs for all transplants in every province and hospital in China. At the national organ transplant congress on October 30, 2014, the Chairman of the China's national organ donation and transplantation committee, Jeifu Huang required all hospitals to stop using organs from executed prisoners immediately and the civilian organ donation will be sole source for organ transplant in China starting January 2015. Liver Transpl 21:419–422, 2015. © 2015 AASLD.
Thrombolytic protocol minimizes ischemic‐type biliary complications in liver transplantation from donation after circulatory death donors
Authors: Seal John B. , Bohorquez Humberto , Reichman Trevor , Kressel Adam , Ghanekar Anand , Cohen Ari , McGilvray Ian D. , Cattral Mark S. , Bruce David , Greig Paul , Carmody Ian , Grant David , Selzner Markus , Loss George
Published: December 2014

Liver transplantation (LT) with donation after circulatory death (DCD) donors has been associated with a high rate of ischemic‐type biliary strictures (ITBSs) and inferior graft survival. To investigate the impact of an intraoperative tissue plasminogen activator (tPA) on outcomes following DCD LT, we conducted a retrospective analysis of DCD LT at the Toronto General Hospital (TGH) and the Ochsner Medical Center (OMC). Between 2009 and 2013, 85 DCD LTs were performed with an intraoperative tPA injection (n = 30 at TGH, n = 55 at OMC), and they were compared with 33 DCD LTs without a tPA. Donor and recipient characteristics were similar in the 2 groups. There was no significant difference in the intraoperative packed red blood cell transfusion requirement (3.2 ± 3.4 versus 3.1 ± 2.3 U, P = 0.74). Overall, biliary strictures occurred less commonly in the tPA‐treated group (16.5% versus 33.3%, P = 0.07) with a much lower rate of diffuse intrahepatic strictures (3.5% versus 21.2%, P = 0.005). After 1 and 3 years, the tPA group versus the non‐tPA group had superior patient survival (97.6% versus 87.0% and 92.7% versus 79.7%, P = 0.016) and graft survival (96.4% versus 69.7% and 90.2% versus 63.6%, P < 0.001). In conclusion, a tPA injection into the hepatic artery during DCD LT reduces ITBSs and improves graft and patient survival without increasing the risk for bleeding. Liver Transpl 21:321–328, 2015. © 2015 AASLD.
Analysis of ischemia/reperfusion injury in time‐zero biopsies predicts liver allograft outcomes
Authors: Ali Jason M. , Davies Susan E. , Brais Rebecca J. , Randle Lucy V. , Klinck John R. , Allison Michael E. D. , Chen Yining , Pasea Laura , Harper Simon F. J. , Pettigrew Gavin J.
Published: December 2014

Ischemia/reperfusion injury (IRI) that develops after liver implantation may prejudice long‐term graft survival, but it remains poorly understood. Here we correlate the severity of IRIs that were determined by histological grading of time‐zero biopsies sampled after graft revascularization with patient and graft outcomes. Time‐zero biopsies of 476 liver transplants performed at our center between 2000 and 2010 were graded as follows: nil (10.5%), mild (58.8%), moderate (26.1%), and severe (4.6%). Severe IRI was associated with donor age, donation after circulatory death, prolonged cold ischemia time, and liver steatosis, but it was also associated with increased rates of primary nonfunction (9.1%) and retransplantation within 90 days (22.7%). Longer term outcomes in the severe IRI group were also poor, with 1‐year graft and patient survival rates of only 55% and 68%, respectively (cf. 90% and 93% for the remainder). Severe IRI on the time‐zero biopsy was, in a multivariate analysis, an independent determinant of 1‐year graft survival and was a better predictor of 1‐year graft loss than liver steatosis, early graft dysfunction syndrome, and high first‐week alanine aminotransferase with a positive predictive value of 45%. Time‐zero biopsies predict adverse clinical outcomes after liver transplantation, and severe IRI upon biopsy signals the likely need for early retransplantation. Liver Transpl 21:487‐499, 2015. © 2015 AASLD.
Global dynamics of a competitive system of rational difference equations
Authors: Khan A. Q. , Qureshi M. N.
Published: December 2014

In this paper, we study the qualitative behavior of a competitive system of second‐order rational difference equations. More precisely, we investigate the boundedness character, existence and uniqueness of positive equilibrium point, local asymptotic stability and global stability of the unique positive equilibrium point and rate of convergence of positive solutions of the system. Some numerical examples are given to verify our theoretical results. Copyright © 2014 John Wiley & Sons, Ltd.
Comparative biokinetics and metabolism of pure monomeric, dimeric, and polymeric flavan‐3‐ols: A randomized cross‐over study in humans
Authors: Wiese Stefanie , Esatbeyoglu Tuba , Winterhalter Peter , Kruse Hans‐Peter , Winkler Stephanie , Bub Achim , Kulling Sabine E.
Published: December 2014

Scope

Flavan‐3‐ols are abundant polyphenols in human nutrition and are associated with beneficial health effects. The aim of this study was to comparatively investigate the metabolic fate of (‐)‐epicatechin, procyanidin B1, and polymeric procyanidins in a randomized cross‐over study in humans.

Methods and results

Parent compounds, conjugates, and microbial metabolites were determined in plasma, urine, and faeces by HPLC‐MS and GC‐MS/MS. Glucuronidated, sulfated, and methylated (‐)‐epicatechin and 5‐(3′,4′‐dihydroxyphenyl)‐valerolactone were the dominant metabolites in blood and urine. In addition, minor amounts of procyanidin B1 and 4‐hydroxy‐5‐(3′,4′‐dihydroxyphenyl)valeric acid and their conjugated metabolites were detected. The formation of 5‐(3′,4′‐dihydroxyphenyl)‐valerolactone and 4‐hydroxy‐5‐(3′,4′‐dihydroxyphenyl)valeric acid varied largely between individuals as well as with the degree of polymerization of flavan‐3‐ols. Monomer units were not detectable in plasma or urine after procyanidin B1 and polymeric procyanidin intake. No correlation was found between the intake of flavan‐3‐ols and the occurrence of phenolic acids in blood and urine or the phenolic compound profiles in faeces.

Conclusion

In addition to conjugated metabolites derived from the absorption of monomeric flavan‐3‐ols, 5‐(3′,4′‐dihydroxyphenyl)‐valerolactone represents an important in vivo metabolite of (‐)‐epicatechin and procyanidin B1 produced by the gut microbiota.
Efficient algorithms for the maximum concurrent flow problem
Authors: Bauguion Pierre‐Olivier , Ben‐Ameur Walid , Gourdin Eric
Published: December 2014

In this article, we propose a generic decomposition scheme for the maximum concurrent flow problem. This decomposition scheme encompasses many models, including, among many others, the classical path formulation and the less studied tree formulation, where the flows of commodities sharing a same source vertex are routed on a set of trees. The pricing problem for this generic model is based on shortest‐path computations. We show that the tree‐based linear programming formulation can be solved much more quickly than the path or the aggregated arc‐flow formulation. Some other decomposition schemes can lead to even faster resolution times. Finally, an efficient strongly polynomial‐time combinatorial algorithm is proposed for the single‐source case. © 2014 Wiley Periodicals, Inc. NETWORKS, Vol. 65(1), 56–67. 2015
On the effect of the bulk tangent matrix in partitioned solution schemes for nearly incompressible fluids
Authors: Franci Alessandro , Oñate Eugenio , Carbonell Josep Maria
Published: December 2014

The purpose of this paper is to study the effect of the bulk modulus on the iterative solution of free surface quasi‐incompressible fluids using a mixed partitioned scheme. A practical rule to set up the value of a pseudo‐bulk modulus a priori in the tangent bulk stiffness matrix for improving the conditioning of the linear system of algebraic equations is also given. The efficiency of the proposed strategy is tested in several problems analyzing the advantage of the modified bulk tangent matrix with regard to the stability of the pressure field, the convergence rate and the computational speed of the analyses. The technique has been tested on a finite calculus/particle finite element method Lagrangian formulation, but it can be easily extended to other quasi‐incompressible stabilized finite element formulations. Copyright © 2014 John Wiley & Sons, Ltd.
The genomic landscape of phaeochromocytoma
Authors: Flynn Aidan , Benn Diana , Clifton‐Bligh Roderick , Robinson Bruce , Trainer Alison H , James Paul , Hogg Annette , Waldeck Kelly , George Joshy , Li Jason , Fox Stephen B , Gill Anthony J , McArthur Grant , Hicks Rodney J , Tothill Richard W
Published: December 2014

Phaeochromocytomas (PCCs) and paragangliomas (PGLs) are rare neural crest‐derived tumours originating from adrenal chromaffin cells or extra‐adrenal sympathetic and parasympathetic tissues. More than a third of PCC/PGL cases are associated with heritable syndromes involving 13 or more known genes. These genes have been broadly partitioned into two groups based on pseudo‐hypoxic and receptor tyrosine kinase (RTK) signalling pathways. Many of these genes can also become somatically mutated, although up to one third of sporadic cases have no known genetic driver. Furthermore, little is known of the genes that co‐operate with known driver genes to initiate and drive tumourigenesis. To explore the genomic landscape of PCC/PGL, we applied exome sequencing, high‐density SNP‐array analysis, and RNA sequencing to 36 PCCs and four functional PGL tumours. All tumours displayed low mutation frequency, in contrast to frequent large segmental copy‐number alterations, aneuploidy, and evidence for chromothripsis in one case. Multi‐region sampling of one benign familial PCC tumour provided evidence for the timing of mutations during tumourigenesis and ongoing clonal evolution. Thirty‐one of 40 (77.5%) cases could be explained by germline or somatic mutations or structural alterations affecting known PCC/PGL genes. Deleterious somatic mutations were also identified in known tumour‐suppressor genes associated with genome maintenance and epigenetic modulation. A multitude of other genes were also found mutated that are likely important for normal neuroendocrine cell function. We revisited the gene‐expression subtyping of PCC/PGL by integrating published microarray data with our RNA‐seq data, enabling the identification of six robust gene‐expression subtypes. The majority of cases in our cohort with no identifiable driver mutation were classified into a gene‐expression subtype bearing similarity to MAX mutant PCC/PGL. Our data suggest there are yet unknown PCC/PGL cancer genes that can phenocopy MAX mutant PCC/PGL tumours. This study provides new insight into the molecular diversity and genetic origins of PCC/PGL tumours. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Non‐toxic luminescent carbon dot/poly(dimethylacrylamide) nanocomposite reagent for latent fingermark detection synthesized via surface initiated reversible addition fragmentation chain transfer polymerization
Authors: Dilag Jessirie , Kobus Hilton , Yu Yang , Gibson Christopher T , Ellis Amanda V
Published: December 2014

Here, non‐toxic luminescent carbon nanoparticles, namely carbon dots (C‐dots), were facilely synthesized via a one‐pot hydrothermal route. Raman, Fourier transform infrared, fluorescence, carbon NMR and X‐ray photoelectron spectroscopies revealed that the C‐dots possessed a graphitic‐like core with an oxidized surface. The oxidized surface of the C‐dots allowed for functionalization of the C‐dots with a 2‐methyl‐2‐[(dodecylsulfanylthiocarbonyl)sulfanyl]propanoic acid chain transfer agent. Poly(N,N‐dimethylacrylamide) (p(DMA)) was then grafted from the C‐dot surface via surface initiated reversible addition fragmentation chain transfer (RAFT) polymerization. The resulting luminescent C‐dot/polymer nanocomposite, C‐dot/p(DMA), was analyzed using UV−visible and fluorescence spectrometry verifying that the functionalized surface was responsible for the C‐dots' luminescence. This C‐dot/p(DMA) nanocomposite was water soluble and was used as a solution for the luminescent detection of latent fingermarks deposited on non‐porous aluminium foil substrates. © 2014 Society of Chemical Industry
Advances in high‐resolution accurate mass spectrometry application to targeted proteomics
Authors: Lesur Antoine , Domon Bruno
Published: December 2014

Targeted quantitative proteomic analyses aim at systematically measuring the abundance of proteins in large sets of samples, without biases or missing values. One typical implementation is the verification of biomarker candidates in bodily fluids, which measures extended lists of validated transitions using triple quadrupole instruments in selected reaction monitoring (SRM) mode. However, the selectivity of this mass spectrometer is limited by the resolving power of its mass analyzers, and interferences may require the reanalysis of the samples. Despite the efforts undertaken in the development of software, and resources to design SRM studies, and to analyze and validate the data, the process remains tedious and time consuming. The development of fast scanning high‐resolution and accurate mass (HRAM) spectrometers, such as the quadrupole TOF and the quadrupole orbitrap instruments, offers alternatives for targeted analyses. The selectivity of HRAM measurements in complex samples is greatly improved by effectively separating co‐eluting interferences. The fragment ion chromatograms are extracted from the high‐resolution MS/MS data using a narrow mass tolerance. The entire process is straightforward as the selection of fragment ions is performed postacquisition. This account describes the different HRAM techniques and discusses their advantages and limitations in the context of targeted proteomic analyses.
Force balances and dynamical regimes of numerically simulated cold fronts within the boundary layer
Authors: Sinclair V. A. , Keyser D.
Published: December 2014

The governing dynamics of numerically simulated cold fronts, as they collapse towards a minimum cross‐frontal scale, are identified by determining force balances and the Rossby and Ekman numbers in frontal regions. A hierarchy of numerical simulations of cold fronts is performed with the Weather Research and Forecasting model and individual terms in the horizontal momentum equations are calculated from the model output to construct force balances. An inviscid, three‐dimensional, idealized front is simulated at three different horizontal grid spacings (100, 20 and 4 km) and then the experiments are repeated with a planetary boundary layer (PBL) parametrization scheme included. Additionally, a full‐physics simulation of the cold front originally analyzed by Sanders is conducted. The leading edge of the idealized, inviscid cold front is characterized by small Rossby numbers and hence balanced dynamics at all three model resolutions. When the PBL scheme is included, large Rossby numbers and unbalanced flow develop at the leading edge of the cold front, but only when the front is simulated at high resolution; at coarse resolution, balanced dynamics remain. The acceleration is in the cross‐front direction and arises due to a localized pressure gradient force. Unlike the inviscid experiments or the coarse‐resolution PBL experiments, the front in the high‐resolution PBL experiment has a large cross‐front thermal gradient, strong forced ascent and sharp surface pressure trough, which enables a large cross‐front pressure gradient force to develop. The dynamics of the Sanders front agree qualitatively with the idealized PBL simulation, but much larger Rossby numbers occur at the leading edge of the Sanders front. This finding indicates that the dynamics of the Sanders front are more unbalanced than the dynamics of the idealized simulations.
Culturally Diverse Literature
Authors: Boyd Fenice B. , Causey Lauren L. , Galda Lee
Published: December 2014

The authors argue for the overwhelming importance of finding and including culturally diverse literature into the curricula teachers are authorized to teach. They discuss the implications of use and offer ideas on how to identify quality literature to include in classroom and school libraries.
Genetic Information‐Seeking Behaviors and Knowledge among Family Members and Patients with Inherited Bone Marrow Failure Syndromes
Authors: Hamilton Jada G. , Hutson Sadie P. , Frohnmayer Amy E. , Han Paul K. J. , Peters June A. , Carr Ann G. , Alter Blanche P.
Published: December 2014

Inherited bone marrow failure syndromes (IBMFS) including Fanconi anemia, dyskeratosis congenita, Diamond‐Blackfan anemia, and Shwachman‐Diamond syndrome are rare genetic disorders characterized by hematologic complications and increased risk of cancer. Patients and their families likely experience obstacles in obtaining sufficient health information given their disorders’ rarity. To investigate this possibility, we examined information‐seeking behaviors and levels of general and disorder‐specific genetic knowledge among 315 members of 174 families with an IBMFS, and how information‐seeking behaviors and socio‐demographic factors may be associated with their genetic knowledge. Cross‐sectional survey data indicated that participants were most likely to have ever used the Internet or healthcare providers for genetic information. On average, participants correctly answered 57 % of items assessing general genetic knowledge and 49–59 % of disorder‐specific knowledge items. Greater knowledge was associated with greater education and ever experiencing genetic counseling, attending a scientific meeting, and seeking information from the Internet and scientific literature. Among families with Fanconi anemia (whose family support organization has the longest history of providing information), greater disorder‐specific genetic knowledge was also associated with seeking information from support groups and other affected families. Results suggest that families with IBMFS have uncertainty regarding genetic aspects of their disorder, and highlight potential channels for delivering educational resources.
Battle of the hemichannels – Connexins and Pannexins in ischemic brain injury
Authors: Davidson J.O. , Green C.R. , Bennet L. , Gunn A.J.
Published: December 2014

Perinatal ischemic brain injury can occur as a result of a global ischemic insult or focal ischemic stroke in the preterm or full‐term neonate. One of the most striking features of HI injury is that, after initial recovery of cellular oxidative metabolism, there is a delayed, ‘secondary’ mitochondrial failure that spreads over time from the most severely damaged areas outwards, into previously undamaged regions. This secondary failure is accompanied by transient seizure activity and cytotoxic edema.

The specific mechanisms of this spread are poorly understood, but it is at least partly associated with spreading waves of depression that can trigger cell death in neighboring uninjured tissues. Both Connexin and Pannexin hemichannels may mediate release of paracrine molecules that in turn propagate cell death messages by releasing intracellular mediators, such as ATP, NAD+, or glutamate or by abnormally prolonged opening to allow cell edema. This review will discuss the controversy around the relative contribution of both Connexin and Pannexin hemichannels and mechanisms by which they may contribute to the spread of ischemic brain injury.
Status epilepticus in adults: A study from Nigeria
Authors: Owolabi Lukman , Ibrahim Aliyu , Mohammed Alhassan , Owolabi Shakirah
Published: December 2014

Background Status epilepticus (SE) is a common neurologic emergency. Immediate treatment to stop seizure activity and prompt diagnostic evaluation to recognize potentially treatable causes are paramount in the management of SE. Thus, increased awareness of presentation, etiologies, and treatment of status epilepticus SE is central in the practice of critical care medicine. However, there is a paucity of information on SE from Nigeria.

Objective We evaluated the clinical profile and predictors of one-month outcome in a group of Nigerian patients with SE.

Methodology Patients with SE were recruited from the medical, high dependency unit, intensive care unit and accident and emergency departments of a tertiary hospital from 2008 to 2013. The outcome was assessed using Glasgow Outcome Score (GOS). The outcome, which was categorized into dead (GOS = 1) or alive was analyzed in a multivariate logistic regression model.

Result A total of 76 patients was studied. The four most common underlying etiologies were stroke, antiepileptic drug (AED) non-compliance, CNS infections and metabolic derangement. Fifty-nine (77.6%) patients survived. Duration of seizure, delay in initiation of treatment (Odd ratio (OR) = 4.4, 95% CI = 1.17–16.56), refractory status epilepticus (OR = 87.1, 95% CI = 12.94–781.1) were significantly associated with death. On multivariate analysis, however, refractory status epilepticus remained an independent predictor of death.

Conclusion Our study showed that the most common underlying etiologies in SE were stroke, antiepileptic drug non-compliance CNS infections and metabolic derangement. Duration of seizure, delay in treatment and refractory the SE were significantly associated with death, but refractory seizure was an independent predictor of death in SE.
Problem‐solving effort and success in innovation contests: The role of national wealth and national culture
Authors: Bockstedt Jesse , Druehl Cheryl , Mishra Anant
Published: December 2014

Innovation contests allow firms to harness specialized skills and services from globally dispersed participants for solutions to business problems. Such contests provide a rich setting for operations management (OM) scholars to explore problem solving in global labor markets as firms continue to unbundle their innovation value chains. In this study, we examine the implications of specific types of diversity in innovation contests on problem‐solving effort and success. First, we conceptualize diversity among contestants in terms of national wealth (measured as gross domestic product per capita (GDPP) adjusted for purchasing power parity) and national culture (measured using the culture dimensions of performance orientation and uncertainty avoidance) and examine how such factors influence problem‐solving effort. Next, we examine how differences between contestants and contest holders in terms of the above factors influence contest outcomes. Using data from a popular online innovation contest platform and country‐level archival data, we find that contestants from countries with lower levels of GDPP are more likely to exert greater problem‐solving effort compared to other contestants. With regard to national culture, we find that performance orientation and uncertainty avoidance have positive and negative effects, respectively, each of which weakens with increasing levels of GDPP. Finally, our analysis provides evidence of homophily effects indicating that contestants who share greater similarities with the contest holder in terms of national wealth and national culture are more likely to be successful in a contest. We discuss the implications of the study's findings for contest holders and platform owners who organize innovation contests, and for emerging research on innovation contests.
Utilization of 18F‐FDG PET/CT as a staging tool in patients with newly diagnosed lymphoma
Authors: Cho Shih‐Feng , Chang Chin‐Chuan , Liu Yi‐Chang , Chang Chao‐Sung , Hsiao Hui‐Hua , Liu Ta‐Chih , Huang Chiung‐Tang , Lin Sheng‐Fung
Published: December 2014

The aim of this study was to investigate the role of 2‐fluorine‐18‐fluoro‐2‐deoxy‐D‐glucose (18F‐FDG) positron emission tomography/computed tomography (PET/CT) in the initial staging and prediction of bone marrow involvement in patients with newly diagnosed lymphoma. A total of 185 patients with newly diagnosed lymphoma were enrolled. All patients received PET/CT and bone marrow biopsy as part of a staging work‐up. At the initial staging, 17 patients (9.2%) with occult nodal or extranodal lesions were upstaged after a review of the PET/CT studies. PET/CT was found to be useful in the differentiation of aggressive lymphoma subtypes from the indolent subtype based on higher standardized uptake value (SUV) (16.67 vs. 7.98, p < 0.001). The results of bone marrow biopsy and PET/CT in the detection of bone marrow involvement were concordant in 152 patients (82.1%); positive concordance was observed in 21 patients, and negative concordance was observed in 131 patients. A high concordance rate was found between aggressive B cell lymphoma and Hodgkin's lymphoma (88.1% and 93.8%, respectively). High negative predictive values (NPVs) for excluding bone marrow involvement were observed in aggressive B‐cell lymphoma (93.2%) and Hodgkin's lymphoma (100%). Diffuse bone marrow FDG uptake accurately predicted bone marrow in aggressive B‐cell lymphoma with a positive predictive value (PPV) of 100%. The concordance rate was lower in indolent B‐cell lymphoma (66.0%). In conclusion, PET/CT resulted in the upstaging of patients with occult extranodal or nodal lesions. A high SUV level can predict aggressive subtype of lymphoma and detect aggressive components in indolent lymphoma. PET/CT had a high PPV for aggressive B‐cell lymphoma with diffuse bone marrow FDG uptake and high NPVs for excluding bone marrow involvement in aggressive B‐cell lymphoma and Hodgkin's lymphoma. Bone marrow biopsy may be omitted for the above subgroups of patients with medical conditions not suitable for this procedure. For patients with indolent B‐cell lymphoma, bone marrow biopsy is still an indispensable procedure for staging.
Nanoparticle hardness controls the internalization pathway for drug delivery
Authors: Li Ye , Zhang Xianren , Cao Dapeng
Published: December 2014

Rigid nanoparticles may internalize by an endocytic pathway, whereas soft nanoparticles tend to find a penetration pathway to enter biomembranes.
Micro-nanostructured CuO/C spheres as high-performance anode materials for Na-ion batteries
Authors: Lu Yanying , Zhang Ning , Zhao Qing , Liang Jing , Chen Jun
Published: December 2014

Micro-nanostructured CuO/C spheres, which were synthesized by aerosol spray pyrolysis, show high performance as anode materials for Na-ion batteries.
Optical and photoacoustic dual-modality imaging guided synergistic photodynamic/photothermal therapies
Authors: Yan Xuefeng , Hu Hao , Lin Jing , Jin Albert J. , Niu Gang , Zhang Shaoliang , Huang Peng , Shen Baozhong , Chen Xiaoyuan
Published: December 2014

A photo-theranostic platform was developed for enhanced fluorescence/photoacoustic dual-modality imaging and synergistic photodynamic/photothermal therapies.
Quantization of borderline Levi conjugacy classes of orthogonal groups
Authors: Ashton Thomas , Mudrov Andrey
Published: December 2014

We construct an equivariant quantization of a special family of Levi conjugacy classes of the complex orthogonal group SO(N), whose stabilizer contains a Cartesian factor SO(2) × SO(P), 1 ⩽ P < N, P ≡ N mod 2.
Absolute determination of photoluminescence quantum efficiency using an integrating sphere setup
Authors: Leyre S. , Coutino-Gonzalez E. , Joos J. J. , Ryckaert J. , Meuret Y. , Poelman D. , Smet P. F. , Durinck G. , Hofkens J. , Deconinck G. , Hanselaer P.
Published: December 2014

An integrating sphere-based setup to obtain a quick and reliable determination of the internal quantum efficiency of strongly scattering luminescent materials is presented. In literature, two distinct but similar measurement procedures are frequently mentioned: a “two measurement” and a “three measurement” approach. Both methods are evaluated by applying the rigorous integrating sphere theory. It was found that both measurement procedures are valid. Additionally, the two methods are compared with respect to the uncertainty budget of the obtained values of the quantum efficiency. An inter-laboratory validation using the two distinct procedures was performed. The conclusions from the theoretical study were confirmed by the experimental data.
Rate-state friction in microelectromechanical systems interfaces: Experiment and theory
Authors: Shroff Sameer S. , Ansari Naveed , Robert Ashurst W. , de Boer Maarten P.
Published: December 2014

A microscale, multi-asperity frictional test platform has been designed that allows for wide variation of normal load, spring constant, and puller step frequency. Two different monolayer coatings have been applied to the surfaces—tridecafluorotris(dimethylamino)silane (FOTAS, CF3(CF2)5(CH2)2 Si(N(CH3)2)3) and octadecyltrichlorosilane (OTS, CH3(CH2)17SiCl3). Static friction aging was observed for both coatings. Simulating the platform using a modified rate-state model with discrete actuator steps results in good agreement with experiments over a wide control parameter subspace using system parameters extracted from experiments. Experimental and modeling results indicate that (1) contacts strengthen with rest time, exponentially approaching a maximum value and rejuvenating after inertial events, and (2) velocity strengthening is needed to explain the shorter than expected length of slips after the friction block transitions from a stick state. We suggest that aging occurs because tail groups in the monolayer coatings reconfigure readily upon initial contact with an opposing countersurface. The reconfiguration is limited by the constraint that head groups are covalently bound to the substrate.
Non-additivity between substitution and cooperative effects in enhancing hydrogen bonds
Authors: Zhuo Hongying , Li Qingzhong , Li Wenzuo , Cheng Jianbo
Published: December 2014

Ternary systems XO2F:NCH:NCY and XO2F:CNH:CNY (X = P and As; Y = H and Li) as well as the corresponding binary ones were studied at the MP2/aug-cc-pVTZ level. Interestingly, the π-hole pnicogen bond in the PO2F complex is stronger than that in the AsO2F counterpart. The substituent Li in the Lewis base strengthens the hydrogen bond and pnicogen bond, but the more prominent enhancing effect is found for the pnicogen bond. The substitution effect is governed mainly through electrostatic interaction for the hydrogen bond but a combination of electrostatic and polarization interactions for the pnicogen bond. In the ternary systems, the π-hole pnicogen bond exhibits a positive cooperative effect with the hydrogen bond. Energy decomposition analysis indicates that the cooperativity is mainly attributed to the polarization energy. There is positive non-additivity between the substitution and cooperative effects, which is an effective measure for strengthening the hydrogen bond. The largest interaction energies occur in AsO2F:CNH:CNLi, amounting to −130.24 kJ/mol for the pnicogen bond and −119.90 kJ/mol for the hydrogen bond, and the former is a covalent interaction and the latter is an ion-pair hydrogen bond.
The ground state and electronic structure of Gd@C82: A systematic theoretical investigation of first principle density functionals
Authors: Dai Xing , Gao Yang , Xin Minsi , Wang Zhigang , Zhou Ruhong
Published: December 2014

As a representative lanthanide endohedral metallofullerene, Gd@C82 has attracted a widespread attention among theorists and experimentalists ever since its first synthesis. Through comprehensive comparisons and discussions, as well as references to the latest high precision experiments, we evaluated the performance of different computational methods. Our results showed that the appropriate choice of the exchange-correlation functionals is the decisive factor to accurately predict both geometric and electronic structures for Gd@C82. The electronic structure of the ground state and energy gap between the septet ground state and the nonet low-lying state obtained from pure density functional methods, such as PBE and PW91, are in good agreement with current experiment. Unlike pure functionals, the popularly used hybrid functionals in previous studies, such as B3LYP, could infer the qualitative correct ground state only when small basis set for C atoms is employed. Furthermore, we also highlighted that other geometric structures of Gd@C82 with the Gd staying at different positions are either not stable or with higher energies. This work should provide some useful references for various theoretical methodologies in further density functional studies on Gd@C82 and its derivatives in the future.
Coarse-graining in simulations of multicomponent polymer systems
Authors: Sethuraman Vaidyanathan , Nguyen Bryan H. , Ganesan Venkat
Published: December 2014

We investigate the mapping required between the interaction parameters of two different coarse-grained simulation models to ensure a match of the long-range structural characteristics of multicomponent polymeric system. The basis for our studies is the recent work of Morse and workers, which demonstrated the existence of a mapping between the interaction parameters of different coarse-grained simulation models which allow for a matching of the peak of the disordered state structure factor in symmetric diblock copolymers. We investigate the extensibility of their results to other polymeric systems by studying a variety of systems, including, asymmetric diblock copolymers, symmetric triblock copolymers, and diblock copolymer-solvent mixtures. By using the mapping deduced in the context of symmetric diblock copolymers, we observe excellent agreement for peak in the inverse structure between both two popular coarse grained models for all sets of polymeric melt systems investigated, thus showing that the mapping function proposed for diblock copolymer melts is transferable to other polymer melts irrespective of the blockiness or overall composition. Interestingly, for the limited parameter range of polymer-solvent systems investigated in this article, the mapping functions developed for polymer melts are shown to be equally effective in mapping the structure factor of the coarse-grained simulation models. We use our findings to propose a methodology to create ordered morphologies in simulations involving hard repulsive potentials in a computationally efficient manner. We demonstrate the outcomes of methodology by creating lamellar and cylindrical phases of diblock copolymers of long chains in the popularly used Kremer-Grest simulation model.
Generation of high-energy mono-energetic heavy ion beams by radiation pressure acceleration of ultra-intense laser pulses
Authors: Wu D. , Qiao B. , McGuffey C. , He X. T. , Beg F. N.
Published: December 2014

Generation of high-energy mono-energetic heavy ion beams by radiation pressure acceleration (RPA) of intense laser pulses is investigated. Different from previously studied RPA of protons or light ions, the dynamic ionization of high-Z atoms can stabilize the heavy ion acceleration. A self-organized, stable RPA scheme specifically for heavy ion beams is proposed, where the laser peak intensity is required to match with the large ionization energy gap when the successive ionization state passes the noble gas configurations [such as removing an electron from the helium-like charge state (Z−2)+ to (Z−1)+]. Two-dimensional particle-in-cell simulations show that a mono-energetic Al13+ beam with peak energy 1.0 GeV and energy spread of only 5% can be obtained at intensity of 7×1020 W/cm2 through the proposed scheme. A heavier, mono-energetic, ion beam (Fe26+) can attain a peak energy of 17 GeV by increasing the intensity to 1022 W/cm2.
Thermal and mechanical response of particulate composite plates under inertial excitation
Authors: Miller Jacob K. , Woods Daniel C. , Rhoads Jeffrey F.
Published: December 2014

The thermal and mechanical, near-resonant responses of particulate composite plates formed from hydroxyl-terminated polybutadiene (HTPB) binder and varying volume ratios of ammonium chloride (NH4Cl) particles (50, 65, 75%) are investigated. Each test specimen is clamped and forced with three levels of band-limited, white noise inertial excitation (10–1000 Hz at 1.00, 1.86 and 2.44 g RMS). The mechanical response of each plate is recorded via scanning laser Doppler vibrometry. The plates are then excited at a single resonant frequency and the thermal response is recorded via infrared thermography. Comparisons are made between the mechanical operational deflection shapes of each plate and spatial temperature distributions, with correlation seen between the observed level of strain, as visualized by strain energy density, and heat generation. The effect of particle/binder ratio on both the thermal and mechanical responses is discussed. Acquired results are also compared to an analytical model of the system. The observed thermomechanical effects render an improved understanding of the thermomechanics of plastic-bonded composites, an essential step in support of the development of new technologies for the vapor-based detection of hidden explosives.
Improved equilibrium reconstructions by advanced statistical weighting of the internal magnetic measurements
Authors: Murari A. , Gelfusa M. , Peluso E. , Gaudio P. , Mazon D. , Hawkes N. , Point G. , Alper B. , Eich T. ,   JET-EFDA Contributors
Published: December 2014

In a Tokamak the configuration of the magnetic fields remains the key element to improve performance and to maximise the scientific exploitation of the device. On the other hand, the quality of the reconstructed fields depends crucially on the measurements available. Traditionally in the least square minimisation phase of the algorithms, used to obtain the magnetic field topology, all the diagnostics are given the same weights, a part from a corrective factor taking into account the error bars. This assumption unduly penalises complex diagnostics, such as polarimetry, which have a limited number of highly significant measurements. A completely new method to choose the weights, to be given to the internal measurements of the magnetic fields for improved equilibrium reconstructions, is presented in this paper. The approach is based on various statistical indicators applied to the residuals, the difference between the actual measurements and their estimates from the reconstructed equilibrium. The potential of the method is exemplified using the measurements of the Faraday rotation derived from JET polarimeter. The results indicate quite clearly that the weights have to be determined carefully, since the inappropriate choice can have significant repercussions on the quality of the magnetic reconstruction both in the edge and in the core. These results confirm the limitations of the assumption that all the diagnostics have to be given the same weight, irrespective of the number of measurements they provide and the region of the plasma they probe.
Inverse scattering transform of a new optical short pulse system
Authors: Tchokouansi Hermann T. , Kuetche Victor K. , Kofane Timoleon C.
Published: December 2014

We focus our attention on the coupled short-pulse equation recently derived by Feng [J. Phys. A: Math. Theor. 45, 085202 (2012)] from a two-dimensional Bäcklund transformation of the Toda lattice equation. Investigating the prolongation structure of such a system, we unveil the hidden structural symmetry that governs the dynamics of the wave solutions to the system alongside with the corresponding Lax-pairs. As a matter of illustration, following the Wadati-Konno-Ichikawa scheme, we construct some solitary wave solutions to the system and study their interactions.
Space magnetometer based on an anisotropic magnetoresistive hybrid sensor
Authors: Brown P. , Whiteside B. J. , Beek T. J. , Fox P. , Horbury T. S. , Oddy T. M. , Archer M. O. , Eastwood J. P. , Sanz-Hernández D. , Sample J. G. , Cupido E. , O’Brien H. , Carr C. M.
Published: December 2014

We report on the design and development of a low resource, dual sensor vector magnetometer for space science applications on very small spacecraft. It is based on a hybrid device combining an orthogonal triad of commercial anisotropic magnetoresistive (AMR) sensors with a totem pole H-Bridge drive on a ceramic substrate. The drive enables AMR operation in the more sensitive flipped mode and this is achieved without the need for current spike transmission down a sensor harness. The magnetometer has sensitivity of better than 3 nT in a 0–10 Hz band and a total mass of 104 g. Three instruments have been launched as part of the TRIO-CINEMA space weather mission, inter-calibration against the International Geomagnetic Reference Field model makes it possible to extract physical signals such as field-aligned current deflections of 20–60 nT within an approximately 45 000 nT ambient field.
Collisions of low-energy electrons with cyclohexane
Authors: Barbosa Alessandra Souza , Bettega Márcio H. F.
Published: December 2014

We report calculated cross sections for elastic scattering of low-energy electrons by cyclohexane (c-C6H12). We employed the Schwinger multichannel method implemented with norm-conserving pseudopotentials in the static-exchange and static-exchange plus polarization approximations, for impact energies up to 30 eV. We compare our calculated integral cross section with experimental total cross sections available in the literature. We also compare our calculated differential cross sections (DCSs) with experimental results for benzene and experimental and theoretical results for 1,4-dioxane, in order to investigate the similarities between those molecules under electron collisions. Although benzene is a cyclic six-carbon molecule, as cyclohexane, we found that the differential cross sections of the latter are more similar to those of 1,4-dioxane than those of benzene. These similarities suggest that the geometry may play an important role in the behavior of the DCSs of these molecules. Our integral cross section displays a broad structure at around 8.5 eV, in agreement with the total cross section experimental data of 8 eV and vibrational excitation data of 7.5 eV. The present integral cross section also shows the presence of a Ramsauer-Townsend minimum at around 0.12 eV. In general, our integral cross section shows a qualitative agreement with the experimental total cross section.
Design of set-point weighting PIλ + Dμ controller for vertical magnetic flux controller in Damavand tokamak
Authors: Rasouli H. , Fatehi A.
Published: December 2014

In this paper, a simple method is presented for tuning weighted PIλ + Dμ controller parameters based on the pole placement controller of pseudo-second-order fractional systems. One of the advantages of this controller is capability of reducing the disturbance effects and improving response to input, simultaneously. In the following sections, the performance of this controller is evaluated experimentally to control the vertical magnetic flux in Damavand tokamak. For this work, at first a fractional order model is identified using output-error technique in time domain. For various practical experiments, having desired time responses for magnetic flux in Damavand tokamak, is vital. To approach this, at first the desired closed loop reference models are obtained based on generalized characteristic ratio assignment method in fractional order systems. After that, for the identified model, a set-point weighting PIλ + Dμ controller is designed and simulated. Finally, this controller is implemented on digital signal processor control system of the plant to fast/slow control of magnetic flux. The practical results show appropriate performance of this controller.
A model for arsenic anti-site incorporation in GaAs grown by hydride vapor phase epitaxy
Authors: Schulte K. L. , Kuech T. F.
Published: December 2014

GaAs growth by hydride vapor phase epitaxy (HVPE) has regained interest as a potential route to low cost, high efficiency thin film photovoltaics. In order to attain the highest efficiencies, deep level defect incorporation in these materials must be understood and controlled. The arsenic anti-site defect, AsGa or EL2, is the predominant deep level defect in HVPE-grown GaAs. In the present study, the relationships between HVPE growth conditions and incorporation of EL2 in GaAs epilayers were determined. Epitaxial n-GaAs layers were grown under a wide range of deposition temperatures (TD) and gallium chloride partial pressures (PGaCl), and the EL2 concentration, [EL2], was determined by deep level transient spectroscopy. [EL2] agreed with equilibrium thermodynamic predictions in layers grown under conditions in which the growth rate, RG, was controlled by conditions near thermodynamic equilibrium. [EL2] fell below equilibrium levels when RG was controlled by surface kinetic processes, with the disparity increasing as RG decreased. The surface chemical composition during growth was determined to have a strong influence on EL2 incorporation. Under thermodynamically limited growth conditions, e.g., high TD and/or low PGaCl, the surface vacancy concentration was high and the bulk crystal was close to equilibrium with the vapor phase. Under kinetically limited growth conditions, e.g., low TD and/or high PGaCl, the surface attained a high GaCl coverage, blocking As adsorption. This competitive adsorption process reduced the growth rate and also limited the amount of arsenic that incorporated as AsGa. A defect incorporation model which accounted for the surface concentration of arsenic as a function of the growth conditions, was developed. This model was used to identify optimal growth parameters for the growth of thin films for photovoltaics, conditions in which a high growth rate and low [EL2] could be attained.
A note on the regularity of the solutions to the Navier-Stokes equations via the gradient of one velocity component
Authors: Skalák Zdeněk
Published: December 2014

We present a regularity criterion for the solutions to the Navier-Stokes equations based on the gradient of one velocity component. Starting with the method developed by Cao and Titi [“Global regularity criterion for the 3D Navier-Stokes equations involving one entry of the velocity gradient tensor,” Arch. Ration. Mech. Anal. 202, 919–932 (2011)] for the case of one entry of the velocity gradient and using further some inequalities concerning the anisotropic Sobolev spaces, we show as a main result that a weak solution u is regular on (0, T), T > 0, provided that ∇u3 ∈ Lt(0, T; Ls), where 2/t + 3/s = 3/2 + 3/(4s) and s ∈ (3/2, 2). It improves the known results for s ∈ (3/2, 15/8).