bluuebunny/crossref_metadata_2025 huggingface dataset:
Cell Surface Nucleolin Facilitates Enterovirus 71 Binding and Infection
Authors: Su Pei-Yi , Wang Ya-Fang , Huang Sheng-Wen , Lo Yu-Chih , Wang Ya-Hui , Wu Shang-Rung , Shieh Dar-Bin , Chen Shun-Hua , Wang Jen-Ren , Lai Ming-Der , Chang Chuan-Fa
Published: February 2015

Because the pathogenesis of enterovirus 71 (EV71) remains mostly ambiguous, identifying the factors that mediate viral binding and entry to host cells is indispensable to ultimately uncover the mechanisms that underlie virus infection and pathogenesis. Despite the identification of several receptors/attachment molecules for EV71, the binding, entry, and infection mechanisms of EV71 remain unclear. Herein, we employed glycoproteomic approaches to identify human nucleolin as a novel binding receptor for EV71. Glycoproteins purified by lectin chromatography from the membrane extraction of human cells were treated with sialidase, followed by immunoprecipitation with EV71 particles. Among the 16 proteins identified by tandem mass spectrometry analysis, cell surface nucleolin attracted our attention. We found that EV71 interacted directly with nucleolin via the VP1 capsid protein and that an antinucleolin antibody reduced the binding of EV71 to human cells. In addition, the knockdown of cell surface nucleolin decreased EV71 binding, infection, and production in human cells. Furthermore, the expression of human nucleolin on the cell surface of a mouse cell line increased EV71 binding and conferred EV71 infection and production in the cells. These results strongly indicate that human nucleolin can mediate EV71 binding to and infection of cells. Our findings also demonstrate that the use of glycoproteomic approaches is a reliable methodology to discover novel receptors for pathogens.

IMPORTANCE
Outbreaks of EV71 have been reported in Asia-Pacific countries and have caused thousands of deaths in young children during the last 2 decades. The discovery of new EV71-interacting molecules to understand the infection mechanism has become an emergent issue. Hence, this study uses glycoproteomic approaches to comprehensively investigate the EV71-interacting glycoproteins. Several EV71-interacting glycoproteins are identified, and the role of cell surface nucleolin in mediating the attachment and entry of EV71 is characterized and validated. Our findings not only indicate a novel target for uncovering the EV71 infection mechanism and anti-EV71 drug discovery but also provide a new strategy for virus receptor identification.
Generation of Mutant Uukuniemi Viruses Lacking the Nonstructural Protein NSs by Reverse Genetics Indicates that NSs Is a Weak Interferon Antagonist
Authors: Rezelj Veronica V. , Överby Anna K. , Elliott Richard M.
Published: February 2015

Uukuniemi virus (UUKV) is a tick-borne member of the
Phlebovirus
genus (family
Bunyaviridae
) and has been widely used as a safe laboratory model to study aspects of bunyavirus replication. Recently, a number of new tick-borne phleboviruses have been discovered, some of which, like severe fever with thrombocytopenia syndrome virus and Heartland virus, are highly pathogenic in humans. UUKV could now serve as a useful comparator to understand the molecular basis for the different pathogenicities of these related viruses. We established a reverse-genetics system to recover UUKV entirely from cDNA clones. We generated two recombinant viruses, one in which the nonstructural protein NSs open reading frame was deleted from the S segment and one in which the NSs gene was replaced with green fluorescent protein (GFP), allowing convenient visualization of viral infection. We show that the UUKV NSs protein acts as a weak interferon antagonist in human cells but that it is unable to completely counteract the interferon response, which could serve as an explanation for its inability to cause disease in humans.

IMPORTANCE
Uukuniemi virus (UUKV) is a tick-borne phlebovirus that is apathogenic for humans and has been used as a convenient model to investigate aspects of phlebovirus replication. Recently, new tick-borne phleboviruses have emerged, such as severe fever with thrombocytopenia syndrome virus in China and Heartland virus in the United States, that are highly pathogenic, and UUKV will now serve as a comparator to aid in the understanding of the molecular basis for the virulence of these new viruses. To help such investigations, we have developed a reverse-genetics system for UUKV that permits manipulation of the viral genome. We generated viruses lacking the nonstructural protein NSs and show that UUKV NSs is a weak interferon antagonist. In addition, we created a virus that expresses GFP and thus allows convenient monitoring of virus replication. These new tools represent a significant advance in the study of tick-borne phleboviruses.
Deep Sequencing of Virus-Derived Small Interfering RNAs and RNA from Viral Particles Shows Highly Similar Mutational Landscapes of a Plant Virus Population
Authors: Kutnjak Denis , Rupar Matevž , Gutierrez-Aguirre Ion , Curk Tomaž , Kreuze Jan F. , Ravnikar Maja
Published: February 2015

RNA viruses exist within a host as a population of mutant sequences, often referred to as quasispecies. Within a host, sequences of RNA viruses constitute several distinct but interconnected pools, such as RNA packed in viral particles, double-stranded RNA, and virus-derived small interfering RNAs. We aimed to test if the same representation of within-host viral population structure could be obtained by sequencing different viral sequence pools. Using ultradeep Illumina sequencing, the diversity of two coexisting
Potato virus Y
sequence pools present within a plant was investigated: RNA isolated from viral particles and virus-derived small interfering RNAs (the derivatives of a plant RNA silencing mechanism). The mutational landscape of the within-host virus population was highly similar between both pools, with no notable hotspots across the viral genome. Notably, all of the single-nucleotide polymorphisms with a frequency of higher than 1.6% were found in both pools. Some unique single-nucleotide polymorphisms (SNPs) with very low frequencies were found in each of the pools, with more of them occurring in the small RNA (sRNA) pool, possibly arising through genetic drift in localized virus populations within a plant and the errors introduced during the amplification of silencing signal. Sequencing of the viral particle pool enhanced the efficiency of consensus viral genome sequence reconstruction. Nonhomologous recombinations were commonly detected in the viral particle pool, with a hot spot in the 3′ untranslated and coat protein regions of the genome. We stress that they present an important but often overlooked aspect of virus population diversity.

IMPORTANCE
This study is the most comprehensive whole-genome characterization of a within-plant virus population to date and the first study comparing diversity of different pools of viral sequences within a host. We show that both virus-derived small RNAs and RNA from viral particles could be used for diversity assessment of within-plant virus population, since they show a highly congruent portrayal of the virus mutational landscape within a plant. The study is an important baseline for future studies of virus population dynamics, for example, during the adaptation to a new host. The comparison of the two virus sequence enrichment techniques, sequencing of virus-derived small interfering RNAs and RNA from purified viral particles, shows the strength of the latter for the detection of recombinant viral genomes and reconstruction of complete consensus viral genome sequence.
Dissecting the Roles of the 5′ Exoribonucleases Xrn1 and Xrn2 in Restricting Hepatitis C Virus Replication
Authors: Li You , Yamane Daisuke , Lemon Stanley M.
Published: February 2015

The replication of hepatitis C virus (HCV) is uniquely dependent on a host microRNA, miR-122. Previous studies using genotype 1a H77S.3 virus demonstrated that miR-122 acts in part by protecting the RNA genome from 5′ decay mediated by the cytoplasmic 5′ exoribonuclease, Xrn1. However, this finding has been challenged by a recent report suggesting that a predominantly nuclear exoribonuclease, Xrn2, mediates the degradation of genotype 2a JFH1 RNA. Here, we dissect the roles of these two 5′ exoribonucleases in restricting the replication of different HCV strains and mediating the decay of HCV RNA. Small interfering RNA (siRNA) depletion experiments indicated that Xrn1 restricts replication of all HCV strains tested: JFH1, H77S.3, H77D (a robustly replicating genotype 1a variant), and HJ3-5 (a genotype 1a/2a chimeric virus). In contrast, the antiviral effects of Xrn2 were limited to JFH1 and H77D viruses. Moreover, such effects were not apparent in cells infected with a JFH1 luciferase reporter virus. Whereas Xrn1 depletion significantly slowed decay of JFH1 and HJ3-5 RNAs, Xrn2 depletion marginally enhanced the JFH1 RNA half-life and had no effect on HJ3-5 RNA decay. The positive effects of Xrn1 depletion on JFH1 replication were largely redundant and nonadditive with those of exogenous miR-122 supplementation, whereas Xrn2 depletion acted additively and thus independently of miR-122. We conclude that Xrn1 is the dominant 5′ exoribonuclease mediating decay of HCV RNA and that miR-122 provides protection against it. The restriction of JFH1 and H77D replication by Xrn2 is likely indirect in nature and possibly linked to cytopathic effects of these robustly replicating viruses.

IMPORTANCE
HCV is a common cause of liver disease both within and outside the United States. Its replication is dependent upon a small, liver-specific noncoding RNA, miR-122. Although this requirement has been exploited for the development of an anti-miR-122 antagomir as a host-targeting antiviral, the molecular mechanisms underpinning the host factor activity of miR-122 remain incompletely defined. Conflicting reports suggest miR-122 protects the viral RNA against decay mediated by distinct cellular 5′ exoribonucleases, Xrn1 and Xrn2. Here, we compare the roles of these two exoribonucleases in HCV-infected cells and confirm that Xrn1, not Xrn2, is primarily responsible for decay of RNA in cells infected with multiple virus strains. Our results clarify previously published research and add to the current understanding of the host factor requirement for miR-122.
Pancreaticopleural fistula: an unusual complication of pancreatitis
Authors: Francisco Elsa , Mendes Miguel , Vale Sílvio , Ferreira Joana
Published: February 2015

Pancreaticopleural fistula is an uncommon complication of pancreatitis. The authors describe a case of a man in his mid-40s with a history of alcohol abuse, who presented with dyspnoea and whose chest X-ray revealed a massive left pleural effusion. Further diagnostic work up revealed a pancreaticopleural fistula. There was no improvement with a conservative approach and endoscopic treatment was not feasible, leading to the need for a surgical intervention.
Developing a ward round checklist to improve patient safety
Authors: Hale Gordon , McNab Duncan
Published: February 2015

Checklists have been shown to improve care and reduce morbidity and mortality in the healthcare setting.[1] Their application in safety-critical industries outside of medicine continues to offer a strong argument for their application to medicine.[2] The daily in-patient medical ward round is a complex process and includes multiple potential risks to patient safety. This project aims to evaluate the effectiveness of a ward round review checklist on one general medical ward in a district general hospital in the UK.

A baseline audit was performed, examining case-notes for a set of pre-defined outcome measures relevant to patient safety. Compliance with documentation of each outcome measure was assessed prior to the introduction of a ward round checklist. This was followed by a quality improvement project through the use of PDSA cycles, with the aim of introducing and developing a ward round checklist over a nine month period. Following the introduction of a checklist, overall compliance with documentation of each outcome measure improved from 45% to 89%.

In conclusion, a quality improvement project involving the introduction of a ward round checklist for daily use has resulted in improved documentation of outcome measures that are relevant to patient safety. Teamwork and leadership skills from clinicians committed to improving patient safety is essential to sustaining improvements in traditional ward round practice.
A novel approach to improving coagulation sample ordering in an emergency department
Authors: Murphy Emma , MacGlone Sile , McGroarty Claire
Published: February 2015

Driven by emergency department targets, there is a need for rapid initial assessment and investigations of attendees to the department, and blood tests are often performed before full patient assessment. It has been shown that many investigations ordered in the emergency department are inappropriate. Coagulation samples are acknowledged as one the commonest blood samples requested on admission. We predicted that the majority of the routine coagulation samples performed in our ED department were unnecessary.

We aimed to determine if coagulation tests sent from our department were appropriate, develop guidance for appropriate testing and to increase the percentage of appropriate tests to 90%. Criterion based audit was used. All coagulation samples sent from the ED over a one week period were reviewed and the indications for testing compared to guidance developed by consensus with ED consultants.

On the first data collection, 66 of 369 (17%) samples were deemed appropriate. Feedback to clinical staff was given at educational meetings and appropriate indications discussed. In collaboration with both senior nursing and medical staff, coagulation screen request bottles were removed from the main clinical area and were only available in the resuscitation area.

Following these interventions, 69 of 97 (71%) samples were deemed appropriate and a further intervention is planned to reach our standard.

This improvement could lead to a £100,000 saving annually and a cross-site collaborative study is planned to spread these improvements.
Reducing avoidable time delays in immediate medication administration - learning from a failed intervention
Authors: Nagar Sachin , davey nicola
Published: February 2015

Stat medications are regularly prescribed on hospital wards as part of the ongoing care for patients. Because they are prescribed at variable times that do not coincide with regular nursing drug administration times, they rely on good communication and vigilance on staff to ensure they are administered in a timely manner. Delays in drug administration can lengthen patient recovery times, prolong admission, and can lead to avoidable patient harm and suffering.

While working on a geriatrics ward I noticed that there were often significant delays in administration of stat medications which occurred on a regular basis. I therefore investigated this by collecting data over a two week period to assess the situation based on our current practice. After root cause analysis (figure 1), it became clear that communication between staff was a significant factor in delayed administration. A solution was implemented in the form of "ward bay wall charts" to aid documentation and communication of stat medication requirements between nursing and medical staff with the intention to reduce delays by improving communication.

After gaining support of medical and nursing staff, a trial was undertaken and a further two weeks of data collected to see the effect of the intervention. The results showed that there was an increase in the median time delay (1 hour 34 minutes to 2 hours 26 minutes, a 55% increase in median time delay) after the implementation of the my intervention, suggesting that it actually made communication worse, creating more delays. Subsequent feedback and analysis showed that this was due to a number of factors that led to worsened communication between staff and therefore an increase in medication delays. Early recognition allowed the intervention to be promptly withdrawn and a re-assessment of the nature of the initial problem.

This project highlights the importance of measurement in determining if an intervention actually works and is an improvement on current practice.
Patient handover in orthopaedics, improving safety using Information Technology
Authors: Pearkes Tim
Published: February 2015

Good inpatient handover ensures patient safety and continuity of care. An adjunct to this is the patient list which is routinely managed by junior doctors. These lists are routinely created and managed within Microsoft Excel or Word. Following the merger of two orthopaedic departments into a single service in a new hospital, it was felt that a number of safety issues within the handover process needed to be addressed. This quality improvement project addressed these issues through the creation and implementation of a new patient database which spanned the department, allowing trouble free, safe, and comprehensive handover. Feedback demonstrated an improved user experience, greater reliability, continuity within the lists and a subsequent improvement in patient safety.
Changing trends in the UK management of upper GI bleeding: is there evidence of reduced UK training experience?
Authors: Penny H A , Kurien M , Wong E , Ahmed R , Ejenavi E , Lau M , Romaya C , Gohar F , Dear K L , Kapur K , Hoeroldt B , Lobo A J , Sanders D S
Published: February 2015

Objective

The aim of this study was to evaluate UK trainee experience in endoscopy for acute upper gastrointestinal bleeding (AUGIB).

Methods

Data was prospectively collected from all patients presenting to South Yorkshire Hospitals with AUGIB from September 2011 to December 2011 and compared with data from 1996. Concurrently, all gastroenterology trainees registered with the British Society of Gastroenterology were invited to respond to a web-based questionnaire regarding their experience in AUGIB management.

Results

77% (589/766) of the patient cohort underwent endoscopy for AUGIB; 15% (90/589) were performed by trainees. 7.2% (9/125) of the out of hours endoscopy case load was performed by trainees; all were low-risk or medium-risk cases (pre-endoscopy Rockall score ≤4). During the study period, dual therapy was delivered by a trainee on only four occasions. Comparison with the 1996 cohort demonstrated a marked reduction in the number of trainee performed endoscopies (76% vs 15%; p<0.001). Questionnaires were returned by 51% (245/478) of British Society of Gastroenterology trainees. 81% (198/245) thought that <10% of the gastroscopies they had performed involved therapeutic intervention. 23% (57/245) felt they would not be competent in AUGIB endoscopy by completion of specialty training.

Conclusions

This study demonstrates the decline over time in trainee experience in AUGIB endoscopy. It also highlights a lack of trainee exposure to more challenging cases, out of hours endoscopy and therapeutic procedures. Furthermore, trainees are concerned that a level of competency may not be attained during specialty training. We advocate reviewing UK endoscopic training provision for AUGIB to ensure that experienced endoscopists are produced to meet future service needs.
Pre-travel health preparation for malaria prevention among Hong Kong travellers
Authors: Hung Kevin K C , Lin Agatha K Y , Cheng Calvin K Y , Chan Emily Y Y , Graham Colin A
Published: February 2015

Background

Malaria remains a significant cause of travel-related mortality and morbidity. Asians are known to have higher risks because they are less careful in pre-travel health preparations. This study reports on a cohort of travellers to malaria-prone regions examined in a previous study, which explored general levels of pre-travel health preparation.

Objectives

To describe the preparations taken by travellers at Hong Kong International Airport going to destinations with significant malaria risks according to the WHO.

Method

A cross-sectional survey was conducted by personal interviews at the boarding gates of flights in April 2013. The flights were chosen from those to malaria-prone regions (type I or above) from the 2012 WHO International Travel and Health Country List.

Results

403 respondents (75.6% Chinese ethnicity) were travelling to malaria-prone regions. 95.3% were travelling to developing countries including China, Thailand, Malaysia and India. 55.1% of respondents had taken at least one mosquito prevention measure and 8.9% of respondents had malaria chemoprophylaxis. Stepwise multivariate logistic regression analysis showed that female gender (OR=2.21, 95% CI 1.23 to 3.97), residence outside Hong Kong (OR=2.71, 95% CI 1.46 to 5.04) and travel including rural areas (OR=5.67, 95% CI 3.11 to 10.34) were predictors of optimum pre-travel health preparations.

Conclusions

Underestimation of malaria risks was a major barrier to adequate pre-travel health preparations. Targeted health education and information about risk is necessary to improve levels of travel health preparedness.
Relationships between preptin and osteocalcin in obese, overweight, and normal weight adults
Authors: El-Eshmawy Mervat , Abdel Aal Ibrahim
Published: February 2015

Preptin is an endocrine peptide secreted from pancreatic β cells; it acts as a physiological amplifier of glucose-mediated insulin secretion. Osteocalcin, secreted by osteoblasts, is also involved in the regulation of body energy in that it modulates fat and glucose metabolism. The aim of this study was to investigate circulating preptin and osteocalcin levels and the possible association between them in obese and overweight adults. A total of 100 obese–overweight adults and 50 healthy controls matched for age and sex were enrolled in this study. Anthropometric measurements were taken and fasting glucose, insulin, homeostasis model assessment of insulin resistance (HOMA-IR), lipid profile, preptin, and osteocalcin were assessed. Preptin was significantly higher in obese and overweight subjects than in controls, whereas osteocalcin was significantly lower. In multiple regression analysis, preptin was independently influenced by waist circumference (WC) (β = 3.75, P = 0.03), fasting insulin (β = 4.77, P = 0.01), HOMA-IR (β = 8.21, P = 0.003), and osteocalcin (β = –28.41, P = 0.04). Osteocalcin was independently influenced by body mass index (β = –1.46, P = 0.05), WC (β = –2.04, P = 0.03), fasting insulin (β = –2.69, P = 0.02), HOMA-IR (β = –0.19, P = 0.006), and triglyceride (β = –4.54, P = 0.001). In conclusion, elevated serum preptin and decreased osteocalcin concentrations, together with insulin resistance, are associated with obesity and overweight. Serum preptin is also independently associated with osteocalcin, which may explain, at least in part, the crosstalk between bone and the β cells of the pancreas.
The quantization for in-homogeneous self-similar measures with in-homogeneous open set condition
Authors: Zhu Sanguo
Published: February 2015

Let [Formula: see text] be a family of contractive similitudes satisfying the open set condition. Let ν be a self-similar measure associated with [Formula: see text]. We study the quantization problem for the in-homogeneous self-similar measure μ associated with a condensation system [Formula: see text]. Assuming a version of in-homogeneous open set condition for this system, we prove the existence of the quantization dimension for μ of order r ∈ (0, ∞) and determine its exact value ξr. The finiteness and positivity of the ξr-dimensional upper and lower quantization coefficient are also explored.
RENEWABLE ENERGY CONSUMPTION, POLITICAL AND INSTITUTIONAL FACTORS: EVIDENCE FROM A GROUP OF EUROPEAN, ASIAN AND LATIN AMERICAN COUNTRIES
Authors: APERGIS NICHOLAS , ELEFTHERIOU SOFIA
Published: February 2015

This paper explores the dynamic relationships between renewable energy consumption and a number of institutional and political factors for a group of countries from Europe, Asia and Latin America spanning the period 1995–2011. The paper employs the methodology of long and short-run panel causality approach as well as the methodology of the panel Error Correction model. The empirical findings provide strong evidence that, after controlling the economic environment, both political and institutional factors exert a strong and statistically significant effect on renewable energy consumption. These findings are expected to have serious implications for policies related to clean energy.
A Computable Characterization of the Extrinsic Mean of Reflection Shapes and Its Asymptotic Properties
Authors: Ding Chao , Qi Hou-Duo
Published: February 2015

The reflection shapes of configurations in ℜm with k landmarks consist of all the geometric information that is invariant under compositions of similarity and reflection transformations. By considering the corresponding Schoenberg embedding, we embed the reflection shape space into the Euclidean space of all (k - 1) by (k - 1) real symmetric matrices. In this paper, we provide a computable formula of the extrinsic mean of the reflection shapes in arbitrary dimensions. Moreover, the asymptotic analysis of the extrinsic mean of the reflection shapes is studied. By using the differentiability of spectral operators, we obtain a central limit theorem of the sample extrinsic mean of the reflection shapes. As a direct application, the two-example hypothesis test of the reflection shapes is also derived.
Dynamic cubic instability in a 2D Q-tensor model for liquid crystals
Authors: Iyer Gautam , Xu Xiang , Zarnescu Arghir D.
Published: February 2015

We consider a four-elastic-constant Landau–de Gennes energy characterizing nematic liquid crystal configurations described using the Q-tensor formalism. The energy contains a cubic term and is unbounded from below. We study dynamical effects produced by the presence of this cubic term by considering an L2 gradient flow generated by this energy. We work in two dimensions and concentrate on understanding the relations between the physicality of the initial data and the global well-posedness of the system.
A locking-free model for Reissner–Mindlin plates: Analysis and isogeometric implementation via NURBS and triangular NURPS
Authors: Beirão Da Veiga L. , Hughes T. J. R. , Kiendl J. , Lovadina C. , Niiranen J. , Reali A. , Speleers H.
Published: February 2015

We study a reformulated version of Reissner–Mindlin plate theory in which rotation variables are eliminated in favor of transverse shear strains. Upon discretization, this theory has the advantage that the "shear locking" phenomenon is completely precluded, independent of the basis functions used for displacement and shear strains. Any combination works, but due to the appearance of second derivatives in the strain energy expression, smooth basis functions are required. These are provided by Isogeometric Analysis, in particular, NURBS of various degrees and quadratic triangular NURPS. We present a mathematical analysis of the formulation proving convergence and error estimates for all physically interesting quantities, and provide numerical results that corroborate the theory.
A Hybrid Parallel Implementation of the Aho–Corasick and Wu–Manber Algorithms Using NVIDIA CUDA and MPI Evaluated on a Biological Sequence Database
Authors: Kouzinopoulos Charalampos S. , Assael John-Alexander M. , Pyrgiotis Themistoklis K. , Margaritis Konstantinos G.
Published: February 2015

Multiple matching algorithms are used to locate the occurrences of patterns from a finite pattern set in a large input string. Aho–Corasick and Wu–Manber, two of the most well known algorithms for multiple matching require an increased computing power, particularly in cases where large-size datasets must be processed, as is common in computational biology applications. Over the past years, Graphics Processing Units (GPUs) have evolved to powerful parallel processors outperforming Central Processing Units (CPUs) in scientific calculations. Moreover, multiple GPUs can be used in parallel, forming hybrid computer cluster configurations to achieve an even higher processing throughput. This paper evaluates the speedup of the parallel implementation of the Aho–Corasick and Wu–Manber algorithms on a hybrid GPU cluster, when used to process a snapshot of the Expressed Sequence Tags of the human genome and for different problem parameters.
Inference of Pathway Decomposition Across Multiple Species Through Gene Clustering
Authors: Vitsios Dimitrios M. , Psomopoulos Fotis E. , Mitkas Pericles A. , Ouzounis Christos A.
Published: February 2015

In the wake of gene-oriented data analysis in large-scale bioinformatics studies, focus in research is currently shifting towards the analysis of the functional association of genes, namely the metabolic pathways in which genes participate. The goal of this paper is to attempt to identify the core genes in a specific pathway, based on a user-defined selection of genomes. To this end, a novel algorithm has been developed that uses data from the KEGG database, and through the application of the MCL clustering algorithm, identifies clusters that correspond to different “layers” of genes, either on a phylogenetic or a functional level. The algorithm's complexity, evaluated experimentally, is presented and the results on three characteristic case studies are discussed.
A combination of hadronic form factors for modeling the kaon photoproduction process γp → K+Λ
Authors: Syukurilla L. , Mart T.
Published: February 2015

We have phenomenologically investigated the kaon photoproduction process γp → K+Λ by combining different types of hadronic form factors (HFFs) inside a covariant isobar model. We obtained the best model with the smallest χ2/N by using the dipole form factor in the Born terms and a combination of the dipole, Gaussian, as well as generalized dipole form factors in the hadronic vertices of the nucleon, kaon and hyperon resonances. By utilizing this model we found that the experimental data used in the analysis are internally consistent, whereas the behavior of differential cross-section at forward angles is not significantly affected by the variation of hadronic coupling constants (CCs) and form factor cutoffs in the model.
PENTACENE-BASED ORGANIC THIN FILM TRANSISTOR WITH SiO2 GATE DIELECTRIC
Authors: DEMIR AHMET , BAĞCI SADIK , SAN SAIT EREN , DOĞRUYOL ZEKERIYA
Published: February 2015

An organic thin film transistor (OTFT) based on pentacene was fabricated with SiO 2 as the gate dielectric material. We have investigated the effects of the thickness of pentacene layer and the organic semiconductor (OSC) material on OTFT devices at two different thicknesses. Au metal was deposited for gate, source and drain contacts of the device by using thermal evaporation method. Pentacene thin film layer was also prepared with thermal evaporation. Our study has shown that the change in pentacene thickness makes a noteworthy difference on the field effect mobility (μFET), values, threshold voltages (VT) and on/off current ratios (Ion/Ioff). OTFTs exhibited saturation at the order of μFET of 3.92 cm2/Vs and 0.86 cm2/Vs at different thicknesses. Ion/Ioff and VT are also thickness dependent. Ion/Ioff is 1 × 103, 2 × 102 and VT is 15 V, 27 V of 40 nm and 60 nm, respectively. The optimized thickness of the pentacene layer was found as 40 nm. The effect of the OSC layer thickness on the OTFT performance was found to be conspicuous.
Comments on “Extremal Cayley Digraphs of Finite Abelian Groups” [Intercon. Networks 12 (2011), no. 1-2, 125–135]
Authors: FIOL M. A.
Published: February 2015

We comment on the paper “Extremal Cayley digraphs of finite Abelian groups” [Intercon. Networks 12 (2011), no. 1-2, 125–135]. In particular, we give some counterexamples to the results presented there, and provide a correct result for degree two.
Lower Bounds on Box Counting for Complex Networks
Authors: ROSENBERG ERIC
Published: February 2015

Determining the fractal dimension dBof a complex network requires computing N(s), the minimal number of boxes of size s needed to cover the network. While effective approximation methods for this problem are known, the computation of a lower bound on N(s) has not been studied. We show that a lower bound can be obtained by formulating the covering problem as an uncapacitated facility location problem, and applying dual ascent to the dual of its linear programming relaxation. We illustrate the method on a small example, and provide numerical results on some larger problems. The upper and lower bounds on N(s) can be used to define a linear program which yields upper and lower bounds on dB.
On The Unitary Cayley Ring Signed Graphs$S_n^\oplus$
Authors: SINHA DEEPA , DHAMA AYUSHI
Published: February 2015

A Signed graph (or sigraph in short) is an ordered pair S = (G, σ), where G is a graph G = (V, E) and σ : E → {+, −} is a function from the edge set E of G into the set {+, −}. For a positive integer n > 1, the unitary Cayley graph Xnis the graph whose vertex set is Zn, the integers modulo n and if Undenotes set of all units of the ring Zn, then two vertices a, b are adjacent if and only if a − b ∈ Un. In this paper, we have obtained a characterization of balanced and clusterable unitary Cayley ring sigraph [Formula: see text]. Further, we have established a characterization of canonically consistent unitary Cayley ring sigraph [Formula: see text], where n has at most two distinct odd primes factors. Also sign-compatibility has been worked out for the same.
Local well-posedness of a class of hyperbolic PDE–ODE systems on a bounded interval
Authors: Peralta Gilbert , Propst Georg
Published: February 2015

The well-posedness theory for hyperbolic systems of first-order quasilinear PDE's with ODE's boundary conditions (on a bounded interval) is discussed. Such systems occur in multi-scale blood flow models, as well as valveless pumping and fluid mechanics. The theory is presented in the setting of Sobolev spaces Hm (m ≥ 3 being an integer), which is an appropriate set-up when it comes to proving existence of smooth solutions using energy estimates. A blow-up criterion is also derived, stating that if the maximal time of existence is finite, then the state leaves every compact subset of the hyperbolicity region, or its first-order derivatives blow-up. Finally, we discuss physical examples which fit in the general framework presented.
Amplification of pulses in nonlinear geometric optics
Authors: Coulombel Jean-François , Williams Mark
Published: February 2015

In this companion paper to our study of amplification of wavetrains J.-F. Coulombel, O. Guès and M. Williams, Semilinear geometric optics with boundary amplification, Anal. PDE7(3) (2014) 551–625, we study weakly stable semilinear hyperbolic boundary value problems with pulse data. Here weak stability means that exponentially growing modes are absent, but the so-called uniform Lopatinskii condition fails at some boundary frequency in the hyperbolic region. As a consequence of this degeneracy there is again an amplification phenomenon: outgoing pulses of amplitude O(ε2) and wavelength ε give rise to reflected pulses of amplitude O(ε), so the overall solution has amplitude O(ε). Moreover, the reflecting pulses emanate from a radiating pulse that propagates in the boundary along a characteristic of the Lopatinskii determinant. In the case of N × N systems considered here, a single outgoing pulse produces on reflection a family of incoming pulses traveling at different group velocities. Unlike wavetrains, pulses do not interact to produce resonances that affect the leading order profiles. However, pulse interactions do affect lower-order profiles and so these interactions have to be estimated carefully in the error analysis. Whereas the error analysis in the wavetrain case dealt with small divisor problems by approximating periodic profiles by trigonometric polynomials (which amounts to using a high frequency cutoff), in the pulse case we approximate decaying profiles with nonzero moments by profiles with zero moments (a low frequency cutoff). Unlike the wavetrain case, we are now able to obtain a rate of convergence in the limit describing convergence of approximate to exact solutions.
New tensorial estimates in Besov spaces for time-dependent (2 + 1)-dimensional problems
Authors: Shao Arick
Published: February 2015

In this paper, we consider various tensorial estimates in geometric Besov-type norms on a one-parameter foliation of surfaces with evolving geometries. Moreover, we wish to accomplish this with only very weak control on these geometries. Several of these estimates were proved in [S. Klainerman and I. Rodnianski, Causal geometry of Einstein-vacuum spacetimes with finite curvature flux, Invent. Math. 159 (2005) 437–529; S. Klainerman and I. Rodnianski, Sharp trace theorems for null hypersurfaces on Einstein metrics with finite curvature flux, Geom. Funct. Anal. 16(3) (2006) 164–229], but in very specific settings. A primary objective of this paper is to significantly simplify and make more robust the proofs of the estimates. Another goal is to generalize these estimates to more abstract settings. In [S. Alexakis and A. Shao, On the geometry of null cones to infinity under curvature flux bounds, Class. Quantum Grav. 31 (2014) 195012], we will apply these estimates in order to consider a variant of the problem in [S. Klainerman and I. Rodnianski, Causal geometry of Einstein-vacuum spacetimes with finite curvature flux, Invent. Math. 159 (2005) 437–529], that of a truncated null cone in an Einstein-vacuum spacetime extending to infinity. This analysis will then be used in [S. Alexakis and A. Shao, Bounds on the Bondi energy by a flux of curvature, to appear in J. Eur. Math. Soc.] to study and to control the Bondi mass and the angular momentum under minimal conditions.
On Trapping Porphyrin Free-Bases Between Graphene Oxide Plates
Authors: Montes Carlos J. , Ojeda María Luisa , González Federico , García-Sánchez Miguel Ángel , Rojas Fernando , Velásquez Celso
Published: February 2015

A synergistic combination of properties between graphene oxide (GO) nanosheets and porphyrin molecules has been accomplished via the entrapment of the latter species within the pore space formed by parallel plates of the carbon material. A hybrid material, synthesized in this manner, would likely lead to the development of efficient photovoltaic cells, given the high capacity of porphyrin molecules to absorb sunlight or radiation of wavelength shorter than 700 nm as well as because of the excellent electron conduction and fine solar energy capture that can be achieved by the graphene substrate. Herein, materials consisting of trapped porphyrin molecules in-between GO plates have been prepared to develop preliminary solar cell devices for an efficient capture of sunlight energy. The hybrid systems created this way can be physicochemically characterized through diverse techniques, which include fluorescence emission to confirm and avail both the presence and manifest luminescent characteristics of the tetrapyrrolic species that are captured and retained in-between GO plates.
Fracture Analysis of Sinusoidal CNT-Based Nanocomposites with Uniform and Nonuniform CNT Distributions
Authors: Golestanian Hossein , Hamedi Mahdieh
Published: February 2015

In this investigation, the effects of carbon nanotube (CNT) shape and distribution on nanocomposite failure are investigated. To achieve our goals, nanocomposites consisting of straight and sinusoidal CNTs with uniform and nonuniform distributions have been modeled. Failure of these nanocomposites is investigated using finite element simulations and micromechanics models. Initially, straight CNT-reinforced polymer is simulated and the stress–strain diagram for this nanocomposite is obtained. To validate our models, the simulation results of this nanocomposite are compared with those found in the literature. Then, sinusoidal CNT-reinforced polymers with uniform and nonuniform CNT distributions are modeled. The results are compared to determine the influence of CNT shape and distribution on nanocomposite failure mechanisms.
A Laboratory Plant for Gas Liquefaction
Authors: De Salve M. , Milani D. , Panella B. , Roveta G.
Published: February 2015

A prototype gas liquefaction plant has been designed and manufactured for Politecnico di Torino cryogenic laboratory and has been used for cryogenic applications like superconducting cables and low temperature refrigeration devices. The plant is able to liquefy nitrogen and, by means of little changes, hydrogen and other cryogenic fluids too. The thermal energy is removed by four high speed (up to 360 000 revolutions per minute) helium turbines that are connected in series. The gas liquefaction is carried out by the cooling condensation process of the gas flow that feeds a 0.15 m3 super insulated tank that is cooled inside. The cryogenic system is based on the Claude and Collins cycles, fed with helium that provides the cold sink. The paper shows the characteristics of the plant main components, and the time history of the measured temperatures, pressures, and flow rates during the plant start-up, as well as the steady state liquefied gas production rate. From the energetic point of view, the plant performance is acceptable for a research laboratory and the plant efficiency is not far from that of commercial larger size plants.
Adiabatic Capillary Tube Model for a Carbon Dioxide Transcritical Cycle
Authors: Nunes R. O. , Faria R. N. , Bouzidi N. , Machado L. , Koury R. N. N.
Published: February 2015

This paper presents a mathematical model for a capillary tube using CO2as fluid in steady flow transcritical cycle. The capillary tube is divided into N volumes controls and the model is based on applying the equations of conservation of energy, mass and momentum in the fluid in each of these volumes controls. The model calculates the mass flow of the CO2in the capillary tube as a function of CO2pressures at the inlet and outlet of the capillary and the temperature of CO2at the input of this device. The capillary tube is considered to be adiabatic, and the limit of operation due to blocked flow condition is also considered in the model. The validation of the model was performed with experimental data and the results showed that the model is capable of predicting the mass flow in the capillary tube with errors less than 10%. The model was also used to determine the minimum diameter of the capillary tube for various conditions of CO2transcritical cycle.
The role of Carclaze tin mine in eighteenth and nineteenth century geotourism
Authors: Bristow Colin
Published: February 2015

Carclaze tin mine was an open pit operation which exploited a massive cassiterite-bearing greisen-bordered quartz-tourmaline vein stockwork, straddling the granite margin near St Austell. It became a ‘must-see’ location for visitors to Cornwall from all over Europe in the late eighteenth and early nineteenth centuries, particularly those interested in the then-fashionable pursuits of geology and mineralogy. Intellectually, the early scientific interest in Carclaze can be seen as part of the Enlightenment, but in the nineteenth century the influence of Romanticism can also be detected. Much of the attraction was due to the openness and accessibility of Carclaze pit, which allowed the geology to be easily appreciated. This resulted in the development of the mine being particularly well documented by a large number of contemporary accounts and illustrations, which has also enabled an early, partly underground, canal to be rediscovered. The earliest account was by the Frenchman M. Jars who visited the pit in 1765; this was followed by accounts by other French geotourists from the early to mid-nineteenth century. The Germans Von Oeynhausen and Von Dechen provided the first geological map and cross-section of the pit in 1829. Accounts by local Cornish authors emphasize that Carclaze was a significant ‘sight’ for visitors. The earliest account of the pit by an English geologist was by Adam
Sedgwick in 1822
; in later publications he speculated on the formation of parallel vein swarms and schorl rock, partly based on his observations in Carclaze Old Tin Pit. De la Beche provided a pen-and-ink sketch of the south face of the pit in 1839. There are also many accounts by non-scientific visitors throughout the nineteenth century and, together with published lithographs, these are particularly helpful in describing and showing the methods of mining. Tin extraction from the Old Tin Pit had practically ceased by the mid-nineteenth century as production switched to china clay from new pits to the north. The historic south face of the Old Tin Pit, as illustrated by De La Beche, has survived into the twenty-first century and has been designated a County Geology Site by the Cornwall Geoconservation Group, although it is now threatened by housing and industrial development proposals.
MicroRNAs and the regulation of aldosterone signaling in the kidney
Authors: Butterworth Michael B.
Published: February 2015

The role of small noncoding RNAs, termed microRNAs (miRs), in development and disease has been recognized for many years. The number of miRs and regulated targets that reinforce a role for miRs in human disease and disease progression is ever-increasing. However, less is known about the involvement of miRs in steady-state, nondisease homeostatic pathways. In the kidney, much of the regulated ion transport is under the control of hormonal signaling. Evidence is emerging that miRs are involved in the hormonal regulation of kidney function and, particularly, in ion transport. In this short review, the production and intra- and extracellular signaling of miRs and the involvement of miRs in kidney disease are discussed. The discussion also focuses on the role of these small biological molecules in the homeostatic control of ion transport in the kidney. MiR regulation of and by corticosteroid hormones, in particular the mineralocorticoid hormone aldosterone, is considered. While information about the role of aldosterone-regulated miRs in the kidney is limited, an increase in the research in this area will undoubtedly highlight the involvement of miRs as central mediators of hormonal signaling in normal physiology.
Role of domain calcium in purinergic P2X2 receptor channel desensitization
Authors: Coddou Claudio , Yan Zonghe , Stojilkovic Stanko S.
Published: February 2015

Activation of P2X2 receptor channels (P2X2Rs) is characterized by a rapid current growth accompanied by a decay of current during sustained ATP application, a phenomenon known as receptor desensitization. Using rat, mouse, and human receptors, we show here that two processes contribute to receptor desensitization: bath calcium-independent desensitization and calcium-dependent desensitization. Calcium-independent desensitization is minor and comparable during repetitive agonist application in cells expressing the full size of the receptor but is pronounced in cells expressing shorter versions of receptors, indicating a role of the COOH terminus in control of receptor desensitization. Calcium-dependent desensitization is substantial during initial agonist application and progressively increases during repetitive agonist application in bath ATP and calcium concentration-dependent manners. Experiments with substitution of bath Na+ with N-methyl-d-glucamine (NMDG+), a large organic cation, indicate that receptor pore dilation is a calcium-independent process in contrast to receptor desensitization. A decrease in the driving force for calcium by changing the holding potential from −60 to +120 mV further indicates that calcium influx through the channel pores at least partially accounts for receptor desensitization. Experiments with various receptor chimeras also indicate that the transmembrane and/or intracellular domains of P2X2R are required for development of calcium-dependent desensitization and that a decrease in the amplitude of current slows receptor desensitization. Simultaneous calcium and current recording shows development of calcium-dependent desensitization without an increase in global intracellular calcium concentrations. Combined with experiments with clamping intrapipette concentrations of calcium at various levels, these experiments indicate that domain calcium is sufficient to establish calcium-dependent receptor desensitization in experiments with whole-cell recordings.