bluuebunny/crossref_metadata_2025 huggingface dataset:
At Low pH, Influenza Virus Matrix Protein M1 Undergoes a Conformational Change Prior to Dissociating from the Membrane
Authors: Fontana Juan , Steven Alasdair C.
Published: March 2013

The M1 matrix protein of influenza A virus, which plays multiple roles in virion assembly and infection, underlies the viral envelope. However, previous studies have given differing accounts of the number of layers in the M1-envelope complex and their thicknesses and compositions. To resolve this issue, we performed cryo-electron microscopy and cryo-electron tomography on the self-same specimens. At neutral pH, there were two kinds of complexes, corresponding to a lipid bilayer with embedded glycoproteins, with and without a closely associated, 4-nm-thick sheet of M1 protein. The reported discrepancies arose from differences in imaging conditions, i.e., in defocus and in whole-particle projections versus thin tomographic slices. Exposure of virions to low pH (as in the endosome) promotes membrane fusion, and previous work has shown that the M2 ion channel causes the virion interior to acidify also. We found that after 5 min at pH 4.9, the proportion of virions lacking an M1 layer increased from 10% to 50%. In virions retaining an M1 layer under these conditions, the M1-envelope complex exhibited two states, viz, the original, neutral-pH state and one in which the M1 layer appeared thinner and/or closer to the membrane. These observations extend previous indications that acidic pH causes the M1 layer to dissociate, leaving the envelope more pliable and, consequently, fusion compatible, and they show that dissociation is preceded by a conformational change in M1.
The Hepatitis E Virus Capsid C-Terminal Region Is Essential for the Viral Life Cycle: Implication for Viral Genome Encapsidation and Particle Stabilization
Authors: Shiota Tomoyuki , Li Tian-Cheng , Yoshizaki Sayaka , Kato Takanobu , Wakita Takaji , Ishii Koji
Published: March 2013

Although the C-terminal 52 amino acids (C52aa) of hepatitis E virus (HEV) capsid are not essential for morphology, the C52aa-encoding region is required for replication. Transfection of a C52aa knockdown mutant showed transient growth, and the earliest population included a majority of noninfectious (possibly empty) particles and a minority of infectious particles with C-terminal capsid degradation. Finally, the complete revertant was generated reproducibly. C52aa is essential for the viral life cycle, promoting accurate encapsidation and stabilizing encapsidated particles.
Ovine Fetal Immune Response to Cache Valley Virus Infection
Authors: Rodrigues Hoffmann Aline , Dorniak Piotr , Filant Justyna , Dunlap Kathrin A. , Bazer Fuller W. , de la Concha-Bermejillo Andres , Welsh Christabel Jane , Varner Patricia , Edwards John Francis
Published: March 2013

Cache Valley virus (CVV)-induced malformations have been previously reproduced in ovine fetuses. To evaluate the development of the antiviral response by the early, infected fetus, before the development of immunocompetency, ovine fetuses at 35 days of gestation were inoculatedin uterowith CVV and euthanized at 7, 10, 14, 21, and 28 days postinfection. The antiviral immune response in immature fetuses infected with CVV was evaluated. Gene expression associated with an innate, immune response was quantified by real-time quantitative PCR. The upregulated genes in infected fetuses includedISG15,Mx1,Mx2,IL-1,IL-6,TNF-α,TLR-7, andTLR-8. The amount of Mx1 protein, an interferon-stimulated GTPase capable of restricting growth of bunyaviruses, was elevated in the allantoic and amniotic fluid in infected fetuses. ISG15 protein expression was significantly increased in target tissues of infected animals. B lymphocytes and immunoglobulin-positive cells were detected in lymphoid tissues and in the meninges of infected animals. These results demonstrated that the infected ovine fetus is able to initiate an innate and adaptive immune response much earlier than previously known, which presumably contributes to viral clearance in infected animals.
Reassortment of NS Segments Modifies Highly Pathogenic Avian Influenza Virus Interaction with Avian Hosts and Host Cells
Authors: Petersen Henning , Wang Zhongfang , Lenz Eva , Pleschka Stephan , Rautenschlein Silke
Published: March 2013

Highly pathogenic avian influenza viruses (HPAIV) of subtypes H5 and H7 have caused numerous outbreaks in diverse poultry species and rising numbers of human infections. Both HPAIV subtypes support a growing concern of a pandemic outbreak, specifically via the avian-human link. Natural reassortment of both HPAIV subtypes is a possible event with unpredictable outcome for virulence and host specificity of the progeny virus for avian and mammalian species. NS reassortment of H5N1 HPAIV viruses in the background of A/FPV/Rostock/1934 (H7N1) HPAIV has been shown to change virus replication kinetics and host cell responses in mammalian cells. However, not much is known about the virus-host interaction of such viruses in avian species. In the present study, we show that the NS segment of A/Vietnam/1203/2004 (FPV NS VN, H5N1) HPAIV significantly altered the characteristics of the H7 prototype HPAIV in tracheal organ cultures (TOC) of chicken and turkey
in vitro
, with decreased replication efficiency accompanied by increased induction of type I interferon (IFN) and apoptosis. Furthermore, species-specific differences between chicken and turkey were demonstrated. Interestingly, NS-reassortant FPV NS VN showed an overall highly pathogenic phenotype, with increased virulence and replication potential compared to the wild-type virus after systemic infection of chicken and turkey embryos. Our data demonstrate that single reassortment of an H5-type NS into an H7-type HPAIV significantly changed virus replication abilities and influenced the avian host cell response without prior adaptation.
Regulation of Viral and Cellular Gene Expression by Kaposi's Sarcoma-Associated Herpesvirus Polyadenylated Nuclear RNA
Authors: Rossetto Cyprian C. , Tarrant-Elorza Margaret , Verma Subhash , Purushothaman Pravinkumar , Pari Gregory S.
Published: March 2013

Kaposi's sarcoma-associated herpesvirus (KSHV) is the cause of Kaposi's sarcoma and body cavity lymphoma. In cell culture, KSHV results in a latent infection, and lytic reactivation is usually induced with the expression of K-Rta or by treatment with phorbol 12-myristate 13-acetate (TPA) and/or
n
-butyrate. Lytic infection is marked by the activation of the entire viral genomic transcription cascade and the production of infectious virus. KSHV-infected cells express a highly abundant, long, noncoding transcript referred to as polyadenylated nuclear RNA (PAN RNA). PAN RNA interacts with specific demethylases and physically binds to the KSHV genome to mediate activation of viral gene expression. A recombinant BACmid lacking the PAN RNA locus fails to express K-Rta and does not produce virus. We now show that the lack of PAN RNA expression results in the failure of the initiation of the entire KSHV transcription program. In addition to previous findings of an interaction with demethylases, we show that PAN RNA binds to protein components of Polycomb repression complex 2 (PRC2). RNA-Seq analysis using cell lines that express PAN RNA shows that transcription involving the expression of proteins involved in cell cycle, immune response, and inflammation is dysregulated. Expression of PAN RNA in various cell types results in an enhanced growth phenotype, higher cell densities, and increased survival compared to control cells. Also, PAN RNA expression mediates a decrease in the production of inflammatory cytokines. These data support a role for PAN RNA as a major global regulator of viral and cellular gene expression.
Adeno-Associated Virus-Mediated Gene Transfer Leads to Persistent Hepatitis B Virus Replication in Mice Expressing HLA-A2 and HLA-DR1 Molecules
Authors: Dion Sarah , Bourgine Maryline , Godon Ophélie , Levillayer Florence , Michel Marie-Louise
Published: March 2013

Hepatitis B virus (HBV) persistence may be due to impaired HBV-specific immune responses being unable to eliminate efficiently or cure infected hepatocytes. The immune mechanisms that lead to HBV persistence have not been completely identified, and no appropriate animal model is available for such studies. Therefore, we established a chronic HBV infection model in a mouse strain with human leukocyte antigen A2/DR1 (HLA-A2/DR1) transgenes and an H-2 class I/class II knockout. The liver of these mice was transduced with adeno-associated virus serotype 2/8 (AAV2/8) carrying a replication-competent HBV DNA genome. In all AAV2/8-transduced mice, hepatitis B virus surface antigen, hepatitis B virus e antigen, and HBV DNA persisted in serum for at least 1 year. Viral replication intermediates and transcripts were detected in the livers of the AAV-injected mice. The hepatitis B core antigen was expressed in 60% of hepatocytes. No significant inflammation was observed in the liver. This was linked to a higher number of regulatory T cells in liver than in controls and a defect in HBV-specific functional T-cell responses. Despite the substantial tolerance resulting from expression of HBV antigens in hepatocytes, we succeeded in priming functional HBV-specific T-cell responses in peripheral tissues, which subsequently reached the liver. This AAV2/8-HBV-transduced HLA-A2/DR1 murine model recapitulates virological and immunological characteristics of chronic HBV infection, and it could be useful for the development of new treatments and immune-based therapies or therapeutic vaccines for chronic HBV infections.
Infection with 2009 H1N1 Influenza Virus Primes for Immunological Memory in Human Nose-Associated Lymphoid Tissue, Offering Cross-Reactive Immunity to H1N1 and Avian H5N1 Viruses
Authors: Mahallawi Waleed H. , Kasbekar Anand V. , McCormick Maxwell S. , Hoschler Katja , Temperton Nigel , Leong Samuel C. , Beer Helen , Ferrara Francesca , McNamara Paul S. , Zhang Qibo
Published: March 2013

Influenza is a highly contagious mucosal infection in the respiratory tract. The 2009 pandemic H1N1 (pH1N1) influenza virus infection resulted in substantial morbidity and mortality in humans. Little is known on whether immunological memory develops following pH1N1 infection and whether it provides protection against other virus subtypes. An enzyme-linked immunosorbent spot assay was used to analyze hemagglutinin (HA)-specific memory B cell responses after virus antigen stimulation in nose-associated lymphoid tissues (NALT) from children and adults. Individuals with serological evidence of previous exposure to pH1N1 showed significant cross-reactive HA-specific memory B cell responses to pH1N1, seasonal H1N1 (sH1N1), and avian H5N1 (aH5N1) viruses upon pH1N1 virus stimulation. pH1N1 virus antigen elicited stronger cross-reactive memory B cell responses than sH1N1 virus. Intriguingly, aH5N1 virus also activated cross-reactive memory responses to sH1N1 and pH1N1 HAs in those who had previous pH1N1 exposure, and that correlated well with the memory response stimulated by pH1N1 virus antigen. These memory B cell responses resulted in cross-reactive neutralizing antibodies against sH1N1, 1918 H1N1, and aH5N1 viruses. The 2009 pH1N1 infection appeared to have primed human host with B cell memory in NALT that offers cross-protective mucosal immunity to not only H1N1 but also aH5N1 viruses. These findings may have important implications for future vaccination strategies against influenza. It will be important to induce and/or enhance such cross-protective mucosal memory B cells.
Post-traumatic intrahepatic splenosis mimicking a neuroendocrine tumour
Authors: Leong Chee Weng , Menon Tulsi , Rao Sudhakar
Published: March 2013

A 52-year-old man presented with abdominal pain with a background of splenectomy 25 years previously. Initial investigations lead to suspicion of a neuroendocrine tumour. Positron emission tomography octreotide scanning and chromogranin were raised. He subsequently underwent a lateral segmentectomy. The histopathology was consistent with splenosis.

1. Splenosis must be considered as differential in any patient with abdominal symptoms post-traumatic splenectomy.

2. Positron emission tomography (PET) octreotide scanning can detect splenosis giving false positives for a neuroendocrine tumour. This is the first case to describe such an association.
Macular hole formation after toxoplasmic retinochoroiditis
Authors: Panos Georgios D , Papageorgiou Elena , Kozeis Nikolaos , Gatzioufas Zisis
Published: March 2013

A 56-year-old female patient presented with toxoplasmic retinochoroiditis (TR) in the right eye. Optical coherence tomography revealed a full-thickness macular hole (MH) in the affected eye. Fluorescence angiography and indocyanine green-angiography disclosed focal choroidal ischaemia in the area of inflammation. Heidelberg retinal flowmetry confirmed the significant hypoperfusion in this area. Proper medication was administered. Ophthalmological examination 4 weeks later revealed an improvement of the clinical findings without visual restoration. This case supports the clinical hypothesis that retinochoroidal ischaemia due to TR may induce the development of MH, indicating that patients with TR may have a certain risk for MH formation.
Novel stretch-sensor technology allows quantification of adherence and quality of home-exercises: a validation study
Authors: Rathleff Michael Skovdal , Bandholm Thomas , Ahrendt Peter , Olesen Jens Lykkegaard , Thorborg Kristian
Published: March 2013

Objective

To investigate if a new stretch sensor attached to an elastic exercise band can assist health professionals in evaluating adherence to home exercises. More specifically, the study investigated whether health professionals can differentiate elastic band exercises performed as prescribed, from exercises not performed as prescribed.

Methods

10 participants performed four different shoulder-abduction exercises in two rounds (80 exercise scenarios in total). The scenarios were (1) low contraction speed, full range of motion (0–90°), (2) high contraction speed, full range of motion (0–90°), (3) low contraction speed, diminished range of motion (0–45°) and (4) unsystematic pull of the elastic exercise band. Stretch-sensor readings from each participant were recorded and presented randomly to the raters. Two raters were asked to differentiate between unsystematic pull (scenario 4), from shoulder abduction strength exercises (scenarios 1–3). The next two raters were asked to identify the four different exercise scenarios (scenarios 1–4).

Results

The first two raters were able to differentiate between unsystematic pull (scenario 4) from shoulder abduction strength exercises (scenarios 1–3). They made no errors (100% success rate). The second two raters were both able to identify each of the 80 scenarios (scenarios 1–4). They too made no errors (100% success rate).

Conclusions

The stretch-sensor readings from the elastic exercise band allow health professionals to quantify whether strength-exercises have been performed as prescribed. These findings have great implications for future clinical practice and research where home exercises are the drugs-of-choice, as they enable clinicians and researchers to measure the exact adherence and quality of the prescribed exercises.
Meteorological factors and risk of community-acquired Legionnaires’ disease in Switzerland: an epidemiological study
Authors: Conza Lisa , Casati Simona , Limoni Costanzo , Gaia Valeria
Published: March 2013

Objectives

The aim of this study was to identify meteorological factors that could be associated with an increased risk of community-acquired Legionnaires’ disease (LD) in two Swiss regions.

Design

Retrospective epidemiological study using discriminant analysis and multivariable Poisson regression.

Setting

We analysed legionellosis cases notified between January 2003 and December 2007 and we looked for a possible relationship between incidence rate and meteorological factors.

Participants

Community-acquired LD cases in two Swiss regions, the Canton Ticino and the Basle region, with climatically different conditions were investigated.

Primary outcome measures

Vapour pressure, temperature, relative humidity, wind, precipitation and radiation recorded in weather stations of the two Swiss regions during the period January 2003 and December 2007.

Results

Discriminant analysis showed that the two regions are characterised by different meteorological conditions. A multiple Poisson regression analysis identified region, temperature and vapour pressure during the month of infection as significant risk factors for legionellosis. The risk of developing LD was 129.5% (or 136.4% when considering vapour pressure instead of temperature in the model) higher in the Canton Ticino as compared to the Basle region. There was an increased relative risk of LD by 11.4% (95% CI 7.70% to 15.30%) for each 1 hPa rise of vapour pressure or by 6.7% (95% CI 4.22% to 9.22%) for 1°C increase of temperature.

Conclusions

In this study, higher water vapour pressure and heat were associated with a higher risk of community-acquired LD in two regions of Switzerland.
Low prevalence of methicillin-resistantStaphylococcus aureusamong men who have sex with men attending an STI clinic in Amsterdam: a cross-sectional study
Authors: Joore I K C W , van Rooijen Martijn Sebastiaan , Schim van der Loeff Maarten Franciscus , de Neeling A J , van Dam Alje , de Vries Henry J C
Published: March 2013

Objective

Community-associated methicillin-resistantStaphylococcus aureus(CA-MRSA) is common among men who have sex with men (MSM) in the USA. It is unknown whether this is also the case in Amsterdam, the Netherlands.

Design

Cross-sectional study.

Setting

Sexually transmitted infection outpatient low-threshold clinic, Amsterdam, the Netherlands.

Participants

Between October 2008 and April 2010, a total of 211 men were included, in two groups: (1) 74 MSM with clinical signs of a skin or soft tissue infection (symptomatic group) and (2) 137 MSM without clinical signs of such infections (asymptomatic group).

Primary outcome measures

S aureusand MRSA infection and/or colonisation. Swabs were collected from the anterior nasal cavity, throat, perineum, penile glans and, if present, from infected skin lesions. Culture forS aureuswas carried out on blood agar plates and for MRSA on selective chromagar plates after enrichment in broth. If MRSA was found, the spa-gene was sequenced.

Secondary outcome measures

Associated demographic characteristics, medical history, risk factors for colonisation withS aureusand high-risk sexual behaviour were collected through a self-completed questionnaire.

Results

The prevalence ofS aureuscolonisation in the nares was 37%, the pharynx 11%, the perianal region 12%, the glans penis 10% and in skin lesions 40%. In multivariable analysis adjusting for age, anogenitalS aureuscolonisation was significantly associated with the symptomatic group (p=0.01) and marginally with HIV (p=0.06). MRSA was diagnosed in two cases: prevalence 0.9% (95% CI 0.1% to 3.4%)). Neither had CA-MRSA strains.

Conclusions

CA-MRSA among MSM in Amsterdam is rare. Genital colonisation ofS aureusis not associated with high-risk sexual behaviour.
Circles of care: should community development redefine the practice of palliative care?
Authors: Abel Julian , Walter Tony , Carey Lindsay B , Rosenberg John , Noonan Kerrie , Horsfall Debbie , Leonard Rosemary , Rumbold Bruce , Morris Deborah
Published: March 2013

Specialist palliative care, within hospices in particular, has historically led and set the standard for caring for patients at end of life. The focus of this care has been mostly for patients with cancer. More recently, health and social care services have been developing equality of care for all patients approaching end of life. This has mostly been done in the context of a service delivery approach to care whereby services have become increasingly expert in identifying health and social care need and meeting this need with professional services. This model of patient centred care, with the impeccable assessment and treatment of physical, social, psychological and spiritual need, predominantly worked very well for the latter part of the 20th century. Over the last 13 years, however, there have been several international examples of community development approaches to end of life care. The patient centred model of care has limitations when there is a fundamental lack of integrated community policy, development and resourcing. Within this article, we propose a model of care which identifies a person with an illness at the centre of a network which includes inner and outer networks, communities and service delivery organisations. All of these are underpinned by policy development, supporting the overall structure. Adoption of this model would allow individuals, communities, service delivery organisations and policy makers to work together to provide end of life care that enhances value and meaning for people at end of life, both patients and communities alike.
Transvenous to arterial Onyx embolization
Authors: Albuquerque Felipe C , Ducruet Andrew F , Crowley R Webster , Bristol Ruth E , Ahmed Azam , McDougall Cameron G
Published: March 2013

Background/objective

Transarterial infusion of Onyx is now widely used in the treatment of arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVFs). Transvenous Onyx embolization is rarely performed, and usually in cases of carotid cavernous fistulas. We describe a novel technique of transvenous Onyx embolization in the treatment of three high risk DAVFs and one vein of Galen (VOG) AVM.

Methods

Cases were evaluated with specific attention to technical caveats, clinical indications, and complications. Patients were treated during 2011–2012 by two operators (FCA and CGM). Standard transfemoral venous approaches were employed in order to obtain access into the draining venous system in all cases.

Results

Four female patients, aged 5 months to 68 years, were treated. Two patients, one presenting with headache and the other with a bruit, demonstrated high risk DAVFs involving the transverse–sigmoid sinuses. One patient, who was asymptomatic, manifested a high risk ethmoidal DAVF that was discovered incidentally during treatment of a basilar aneurysm. The final patient presented with symptoms of a pineal region mass and was found to have a VOG AVM. In all cases, a microcatheter was navigated through the draining venous pouch and into the ostium of an arterial feeder. A single Onyx infusion from this position filled multiple arterial feeders and resulted in cures in the first three patients and a significant reduction in AVM nidus in the fourth patient. No complications occurred.

Conclusions

Transvenous Onyx infusion into a single arterial feeder can produce retrograde embolization of numerous other arterial feeders supplying high risk DAVFs and complex cerebral AVMs. This technique appears to be safe and potentially curative in select cases.
Endovascular Reperfusion and Cooling in Cerebral Acute Ischemia (ReCCLAIM I)
Authors: Horn Christopher M , Sun Chung-Huan J , Nogueira Raul G , Patel Vishal N , Krishnan Arun , Glenn Brenda A , Belagaje Samir R , Thomas Tommy T , Anderson Aaron M , Frankel Michael R , Schindler Kiva M , Gupta Rishi
Published: March 2013

Background

The efficacy of hypothermia as a neuroprotectant has yet to be demonstrated in acute ischemic stroke. We conducted a phase I pilot study to assess the feasibility and safety of performing intravascular hypothermia after definitive intra-arterial reperfusion therapy (IAT).

Methods

ReCCLAIM (Reperfusion andCooling inCerebralAcuteIschemia) is a prospective single-arm open-label clinical trial conducted between May and August 2012 at Grady Memorial Hospital. Twenty patients with Alberta Stroke Program Early CT Score (ASPECTS) 5–7 and NIH Stroke Scale (NIHSS) score > 13 were enrolled and treated with intravascular cooling immediately after IAT. The incidence of pneumonia, deep vein thrombosis, cardiac arrhythmias and postoperative hemorrhages was documented for the entire length of stay. Secondary outcomes included blood–brain barrier (BBB) breakdown on gadolinium-enhanced MRIs and 90-day modified Rankin scores (mRS).

Results

The mean age, median NIHSS score and median final infarct volume were 59.7±14.6 years, 19 (IQR16–22) and 78 cm3(IQR 16–107), respectively. The average time to the target temperature (33°C) was 64±50 min. Intracranial hemorrhages were found in three patients, of which one was symptomatic. Evidence of BBB breakdown was observed on 3 of 14 MRIs (21%). Six patients died due to withdrawal of care, whereas six patients (30%) achieved mRS of 0–2 at 90 days. In a binary logistical regression model comparing ReCCLAIM patients with 68 historical controls at our institution, hypothermia was protective against intracerebral hemorrhages (OR 0.09, 95% CI 0.02 to 0.56; p<0.01).

Conclusions

Hypothermia can be safely performed after definitive IAT in patients with large pretreatment core infarcts. A phase II study randomizing patients to hypothermia or normothermia is needed to properly assess the efficacy of hypothermia as a neuroprotectant for reperfusion injury.

Trial registration number

NCT01585597.
Resilient modulus of unsaturated subgrade soil: experimental and theoretical investigations
Authors: Ng C.W.W. , Zhou C. , Yuan Q. , Xu J.
Published: March 2013

The resilient modulus, MR, of subgrade soil is an important stiffness parameter for analysing fatigue cracking in either the asphalt or concrete layer of a pavement. Although subgrade soil is often unsaturated and subject to seasonal variations of moisture content and hence suction in the field, effects of soil suction on the resilient modulus are generally not accounted for in existing testing methods. In this study, MRvalues of a subgrade soil under various stress and suction conditions were investigated using a suction-controlled cyclic triaxial apparatus. To enhance the accuracy of measurements, Hall-effect transducers were employed to monitor the local axial and radial deformation of each specimen. It was found that MRincreases with number of load applications when a soil contracts, but decreases slightly when a soil dilates. When suction increases, the soil response tends to change from contractive to dilative due to suction-induced dilatancy. Moreover, the measured MRis highly dependent on the stress state. It decreases with cyclic stress due to the nonlinearity of the soil stress–strain behaviour, but increases significantly with suction due to the presence of water tension. At the same stress and suction conditions, MRmeasured along the wetting path is generally larger than that measured along the drying path. A new semi-empirical equation representing the stress-dependency of MRis proposed and was verified using experimental results of four different soils.
INFORMATION FILTERING BASED ON USERS' NEGATIVE OPINIONS
Authors: GUO QIANG , LI YANG , LIU JIAN-GUO
Published: March 2013

The process of heat conduction (HC) has recently found application in the information filtering [Zhang et al., Phys. Rev. Lett.99, 154301 (2007)], which is of high diversity but low accuracy. The classical HC model predicts users' potential interested objects based on their interesting objects regardless to the negative opinions. In terms of the users' rating scores, we present an improved user-based HC (UHC) information model by taking into account users' positive and negative opinions. Firstly, the objects rated by users are divided into positive and negative categories, then the predicted interesting and dislike object lists are generated by the UHC model. Finally, the recommendation lists are constructed by filtering out the dislike objects from the interesting lists. By implementing the new model based on nine similarity measures, the experimental results for MovieLens and Netflix datasets show that the new model considering negative opinions could greatly enhance the accuracy, measured by the average ranking score, from 0.049 to 0.036 for Netflix and from 0.1025 to 0.0570 for Movielens dataset, reduced by 26.53% and 44.39%, respectively. Since users prefer to give positive ratings rather than negative ones, the negative opinions contain much more information than the positive ones, the negative opinions, therefore, are very important for understanding users' online collective behaviors and improving the performance of HC model.
DETERMINISTIC ANTS IN LABYRINTH — INFORMATION GAINED BY MAP SHARING
Authors: MALINOWSKI JANUSZ , KANTELHARDT JAN W. , KUŁAKOWSKI KRZYSZTOF
Published: March 2013

A few ant robots are placed in a labyrinth, formed by a square lattice with a small number of corridors removed. Ants move according to a deterministic algorithm designed to explore all corridors. Each ant remembers the shape of corridors which it has visited. Once two ants meet, they share the information acquired. We evaluate how the time of getting a complete information by an ant depends on the number of ants, and how the length known by an ant depends on time. Numerical results are presented in the form of scaling relations.
ANALYTICAL RANDOM VIBRATION ANALYSIS OF BOUNDARY-EXCITED THIN RECTANGULAR PLATES
Authors: HOSSEINLOO ASHKAN HAJI , YAP FOOK FAH , VAHDATI NADER
Published: March 2013

Fatigue life, stability and performance of majority of the structures and systems depend significantly on dynamic loadings applied on them. In many engineering cases, the dynamic loading is random vibration and the structure is a plate-like system. Examples could be printed circuit boards or jet impingement cooling systems subjected to random vibrations in harsh military environments. In this study, the response of thin rectangular plates to random boundary excitation is analytically formulated and analyzed. In the presented method, closed-form mode shapes are used and some of the assumptions in previous studies are eliminated; hence it is simpler and reduces the computational load. In addition, the effects of different boundary conditions, modal damping and excitation frequency range on dynamic random response of the system are studied. The results show that increasing both the modal damping ratio and the excitation frequency range will decrease the root mean square acceleration and the maximum deflection of the plate.
IN-PLANE VIBRATION OF CIRCULAR ARCHES WITH VARYING CROSS-SECTIONS
Authors: TUFEKCI EKREM , YIGIT OZNUR OZDEMIRCI
Published: March 2013

The in-plane free vibration of circular arches with continuously varying cross-sections is studied by means of the exact solution. The exact solution can be obtained only for a circular arch with constant cross-section. As an approximation, the circular arch with varying cross-sections is divided into a number of arch elements with constant cross-sections. The cross-section of each arch element is determined by averaging the upper and lower cross-sections. Then, the exact solution of free vibrations for each arch element can be obtained by using the initial value method. The axial extension, transverse shear deformation and rotatory inertia effects are included in the analysis. As the number of the arch elements increases, the fast convergence of the frequencies to those of the original arch is observed. Clamped–clamped (CC), hinged–hinged (HH), hinged–clamped (HC), clamped–free (CF) and free–free (FF) boundary conditions are studied for different opening angles, taper types and taper ratios. A detailed parametric study is performed, by which the mode transition phenomenon is observed. The results obtained are compared with those available in the literature.
IMPORTANCE OF NONLINEARITY OF TRACK SUPPORT SYSTEM IN MODELING OF RAILWAY TRACK DYNAMICS
Authors: SADEGHI J. , FESHARAKI M.
Published: March 2013

Attention is drawn to the fact that the recent increase in axle loads, speed and traffic volume in railway tracks, as well as concerns over passengers' riding comfort and safety have resulted in fresh challenges that are needed to be addressed. These challenges can only be successfully tackled with a more accurate modeling of the dynamic behavior of railway tracks. Although a significant amount of research involving mathematical modeling of railway track dynamics has been conducted in the last two decades, the nonlinearity of track support systems has not been given sufficient attention. This paper is concerned with the effect of nonlinearity of the support sub-layers on the dynamic responses of the railway track. To this end, a railway track model that considers the nonlinear properties of the track sub-layers is developed. Then, a field investigation into the dynamic responses of the railway track system under moving trains is conducted. The effect of the nonlinearity properties of the track support system on the track responses is investigated by comparing the results obtained by the numerical model, with or without consideration of track support nonlinearity, with those from the field tests. It is illustrated that consideration of the nonlinear properties of the track support system improves the accuracy of the calculated responses by a factor of three. It is also shown that the train axle loads and track accumulative loading have a significant effect on the nonlinearity of the track support system and, as a result, on the modeling of track responses.
A MODEL BASED ON ARAS-G AND AHP METHODS FOR MULTIPLE CRITERIA PRIORITIZING OF HERITAGE VALUE
Authors: TURSKIS ZENONAS , ZAVADSKAS EDMUNDAS KAZIMIERAS , KUTUT VLADISLAVAS
Published: March 2013

The paper discusses the meaning and nature of urban cultural heritage, and the available methods for its valuation in the perspective of sustainable city development. From this perspective, decision-making problems of renovation often involve a complex decision-making process in which multiple requirements and conditions have to be taken into consideration simultaneously. In project development it is hardly possible to get exhaustive and accurate information. As a result, the situations occur, the consequences of which can be very damaging to the project. Sometimes the loss is related to symbolic values that the public perceive as disregarded by the project, despite the overall improved conditions. This paper presents the multiple criteria assessment of alternatives of the cultural heritage renovation projects in Vilnius city. The model consists of the following elements: determining attributes set affecting built and human environment renovation; information collection and analysis, decision modeling and solution selection. The main purpose of the model is to improve the condition of the built and human environment through efficient decision making in renovation supported by multiple attribute evaluation. Delphi, AHP and ARAS-G methods, considering different environment factors as well as stakeholders' needs, are applied to solve problem.
A FUZZY APPROACH TO BUSINESS TRAVEL AIRLINE SELECTION USING AN INTEGRATED AHP-TOPSIS-MSGP METHODOLOGY
Authors: LIAO CHIN-NUNG
Published: March 2013

Airline selection is a multi-criteria decision-making (MCDM) problem faced in business travel. The evaluation process primarily involves the evaluation of several complex factors for selecting an airline that will best meet business travel needs. Previous studies have proposed several different methods that a company or organization can use to evaluate or select an airline. In its proposed approach to solving airline selection, this study integrates the analytical hierarchy process (AHP) with a type of preference ordering involving the determination a solution's similarity to an ideal solution (TOPSIS) and multi-segment goal programming (MSGP). A real-life case study on selecting an airline is also presented.
ULTRAFINE AU NANODOTS ON GRAPHENE OXIDE FOR CATALYTIC REDUCTION OF 4-NITROPHENOL
Authors: CHEN JIANLI , CHENG GANG , LI ZHUANGNAN , MIAO FUJUN , CUI XIAOQIANG , ZHENG WEITAO
Published: March 2013

Graphene oxide nanosheet is an ideal platform to capture nanoparticles for highly efficient catalysis, electrochemical sensing and biosensing. In this work, we have described a simple synthesis method for preparation graphene oxide– Au nanohybrid. Au nanodots with an average size of 1.6 nm uniformly dispersed on the surface of graphene oxide. The well-defined nanostructure has been characterized by transmission electron microscopy (TEM) and atomic force microscopy (AFM). The nanohybrid also exhibits enhanced catalytic activity toward the reduction of 4-nitrophenol by NaBH4 . Comparing with pure Au nanodots and graphene oxide, graphene oxide– Au nanohybrid shows the highest catalytic activity. This approach not only suggests a wide potential application of graphene oxide nanosheet as a host material for supporting a variety of nanoparticles, but also provides a new approach for the fabrication of graphene-based nanohybrids with multiple physical and chemical properties.
Pulmonary and cutaneous O2gas exchange: a student laboratory exercise in the frog
Authors: Tattersall Glenn J. , Currie Suzanne , LeBlanc Danielle M.
Published: March 2013

Gas exchange in animals is ultimately diffusion based, generally occurring across dedicated respiratory organs. In many aquatic amphibians, however, multiple modes of gas exchange exist, allowing for the partitioning of O2uptake and CO2excretion between respiratory organs with different efficiencies. For example, due to the physical properties of O2being vastly different between air and water phases, the lung and skin play disproportionately important roles in O2uptake. Many aquatic frogs are renowned for their cutaneous gas exchange capacity, where often the majority of CO2is excreted across the skin. Furthermore, the roles of these gas exchange organs change with the animal's behavior. Under diving conditions, most of the frog's gas exchange needs must be met by the skin. In this article, we describe an interactive undergraduate laboratory that allows a class of students to share equipment while assessing pulmonary and cutaneous respiration in frogs provided with an air/water choice and under enforced dive conditions. Concepts explored in this laboratory exercise include animal energetics, diving reflex, pulmonary and cutaneous gas exchange processes, diffusion-based gas flux, and O2debt.
Effect of an individual readiness assurance test on a team readiness assurance test in the team-based learning of physiology
Authors: Gopalan Chaya , Fox Dainielle J. , Gaebelein Claude J.
Published: March 2013

We examined whether requiring an individual readiness assurance test (iRAT) before a team readiness assurance test (tRAT) would benefit students in becoming better problem solvers in physiology. It was tested in the form of tRAT scores, the time required to complete the tRAT assignment, and individual performance on the unit examinations. Students in one section were given the iRAT at the beginning of the team-based learning session. The same set of questions was given to students as their tRAT immediately after their iRAT. Students in the second section were not given the iRAT before the tRAT. This pattern was reversed for the next scheduled team-based learning activity between the two sections. We found that the section having both the iRAT and tRAT scored higher on the tRAT and completed their assignments in less time than the section with the tRAT alone. This suggests that the tRAT combined with the iRAT is an effective team-based approach to the teaching of physiology compared with the tRAT alone.
Evaluation of a peer mentoring program for a mature cohort of first-year undergraduate paramedic students
Authors: Hryciw Deanne H. , Tangalakis Kathy , Supple Briony , Best Gill
Published: March 2013

The purpose of this study was to evaluate the effectiveness of a peer-assisted study session (PASS) program for a large class of Bachelor of Health Science (Paramedic) students. This cohort was made up predominantly of mature aged students who have not undertaken any study for many years. Within a bioscience first-year core subject, student mentees attended PASS sessions on a voluntary basis, with second-year Bachelor of Health Science (Paramedic) students acting as mentors. Mentors were recruited based on their outstanding academic performance in bioscience the previous year and selected based on group and individual interviews. Successful candidates participated in a compulsory 2 days of student mentor training and were supported throughout the program to develop their mentoring skills in both face-to-face workshops and online. Mentee students were allocated to a PASS session with a maximum size of 25 students/group that was facilitated by 2 student mentors. In general, the program was viewed favorably by both mentors and mentees. There was an increase in academic performance and a decrease in the fail rate of the mentee group compared with the cohort of students that did not participate in the PASS program. Importantly, mentees believed that the program improved their study skills and gave them confidence in their approach to studying. This is a significant consideration for the improvement of student transition and retention in a mature aged student cohort.
A writing-intensive course improves biology undergraduates' perception and confidence of their abilities to read scientific literature and communicate science
Authors: Brownell Sara E. , Price Jordan V. , Steinman Lawrence
Published: March 2013

Most scientists agree that comprehension of primary scientific papers and communication of scientific concepts are two of the most important skills that we can teach, but few undergraduate biology courses make these explicit course goals. We designed an undergraduate neuroimmunology course that uses a writing-intensive format. Using a mixture of primary literature, writing assignments directed toward a layperson and scientist audience, and in-class discussions, we aimed to improve the ability of students to 1) comprehend primary scientific papers, 2) communicate science to a scientific audience, and 3) communicate science to a layperson audience. We offered the course for three consecutive years and evaluated its impact on student perception and confidence using a combination of pre- and postcourse survey questions and coded open-ended responses. Students showed gains in both the perception of their understanding of primary scientific papers and of their abilities to communicate science to scientific and layperson audiences. These results indicate that this unique format can teach both communication skills and basic science to undergraduate biology students. We urge others to adopt a similar format for undergraduate biology courses to teach process skills in addition to content, thus broadening and strengthening the impact of undergraduate courses.
APS at 125: a look back at the founding of the American Physiological Society
Authors: Ryan Kathy L.
Published: March 2013

Early efforts in physiological research in the United States were produced by lone investigators working in laboratories funded by their own medical practices. In Europe, however, Claude Bernard and Carl Ludwig produced a new model of scientific research laboratories funded by the state that sought to develop the pursuit of biomedical research as an occupation. American physicians such as Henry Pickering Bowditch and S. Weir Mitchell were exposed to this new “research ethic” during their international studies and brought this new perspective home to America. Along with H. Newell Martin, these men began training professional physiologists who would assume new research positions in academic institutions. In 1887, Bowditch, Mitchell, and H. Newell Martin proposed the formation of a new society for these professional physiologists, the American Physiological Society (APS). Seventeen of the original twenty-eight members met on December 30, 1887, in New York City, NY, to establish APS. From these humble beginnings, APS evolved to become a force for change in American biomedical science.
Recognition of American Physiological Society members whose research publications had a significant impact on the discipline of physiology
Authors: Tipton Charles M.
Published: March 2013

Society members whose research publication during the past 125 yr had an important impact on the discipline of physiology were featured at the American Physiological Society (APS)'s 125th Anniversary symposium. The daunting and challenging task of identifying and selecting significant publications was assumed by the Steering Committee of the History of Physiology Interest Group, who requested recommendations and rationales from all Sections, select Interest Groups, and active senior APS members. The request resulted in recommendations and rationales from nine Sections, one Interest Group, and 28 senior members, identifying 38 publications and 43 members for recognition purposes. The publication recommendations included 5 individuals (Cournand, Erlanger, Gasser, Hubel, and Wiesel) whose research significantly contributed to their selection for the Nobel Prize in Medicine or Physiology, 4 individuals who received multiple recommendations [i.e., Cannon ( 3 ), Curran ( 2 ), Fenn ( 3 ), and Hamilton ( 2 )], and 11 members who had been APS Presidents. Of the recommended articles, 33% were from the American Journal of Physiology, with the earliest being published in 1898 (Cannon) and the latest in 2007 (Sigmund). For the brief oral presentations, the History of Physiology Steering Committee selected the first choices of the Sections or Interest Group, whereas rationales and representation of the membership were used for the presentations by senior members.
Testosterone enhances tubuloglomerular feedback by increasing superoxide production in the macula densa
Authors: Fu Yiling , Lu Yan , Liu Eddie Y. , Zhu Xiaolong , Mahajan Gouri J. , Lu Deyin , Roman Richard J. , Liu Ruisheng
Published: March 2013

Males have higher prevalence of hypertension and renal injury than females, which may be attributed in part to androgen-mediated effects on renal hemodynamics. Tubuloglomerular feedback (TGF) is an important mechanism in control of renal microcirculation. The present study examines the role of testosterone in the regulation of TGF responses. TGF was measured by micropuncture (change of stop-flow pressure, ΔPsf) in castrated Sprague-Dawley rats. The addition of testosterone (10−7 mol/l) into the lumen increased the ΔPsf from 10.1 ± 1.2 to 12.2 ± 1.2 mmHg. To determine whether androgen receptors (AR) are involved, mRNA of AR was measured in the macula dense cells isolated by laser capture microdissection from kidneys, and a macula densa-like cell line (MMDD1). AR mRNA was expressed in the macula densa of rats and in MMDD1 cells. We next examined the effects of the AR blocker, flutamide (10−5 mol/l) on the TGF response. The addition of flutamide blocked the effects of testosterone on TGF. The addition of Tempol (10−4 mol/l) or polyethylene glycol-superoxide dismutase (100 U/ml) to scavenge superoxide blocked the effect of testosterone to augment TGF. We then applied apocynin to inhibit NAD(P)H oxidase and oxypurinol to inhibit xanthine oxidase and found the testosterone-induced augmentation of TGF was blocked. In additional experiments in MMDD1 cells, we found that testosterone increased O2− generation. Apocynin or oxypurinol blocked the testosterone-induced increases of O2−, while blockade of COX-2 with NS-398 had no effect. These findings suggest that testosterone enhances TGF response by stimulating O2− production in macula densa via an AR-dependent pathway.