bluuebunny/crossref_metadata_2025 huggingface dataset:
Colonic phytobezoar as a rare cause of large bowel obstruction
Authors: Law Gin Way , Lin Diwei , Thomas Rebecca
Published: April 2015

Bezoars are masses formed by the concretion of stomach contents or debris within the gastrointestinal tract. Bezoars are rare and account for only 0.4–4% of all cases of gastrointestinal obstruction and mainly occur in the stomach or small intestine. Intestinal obstruction caused by colonic bezoars is extremely rare. We report a case of a distal sigmoid obstruction caused by a phytobezoar in a 60-year-old man with no obvious precipitating causes. He presented to the emergency department acutely unwell and a subsequent abdominal CT scan showed a mass within the proximal sigmoid colon suspicious for a bezoar. He proceeded to have an urgent laparotomy and the obstructive intraluminal mass in the sigmoid colon was identified and manually broken down. Subsequent histopathological assessment reported amorphous material and plant cellular matter consistent with the diagnosis of a phytobezoar.
Stress-induced cardiomyopathy
Authors: Lisung Fausto Gabriel , Shah Ankit B , Levitt Howard L , Coplan Neil B
Published: April 2015

A woman in her early 70s presented with chest pain, dyspnoea and diaphoresis 30 min after her husband expired in our hospital. Cardiac markers were elevated and there were acute changes in ECG suggestive for acute coronary syndrome. Echocardiogram showed apical akinesis, basal segment hyperkinesis with an ejection fraction of 30%. Cardiac catheterisation was performed showing non-obstructive coronary arteries, leading to the diagnosis of stress-induced cardiomyopathy. The patient improved with medical management. Repeat echocardiogram 2 months later showed resolution of heart failure with an ejection fraction of 65–70%.
Prognostic role of the neutrophil–lymphocyte ratio in renal cell carcinoma: a meta-analysis
Authors: Hu Kaimin , Lou Lixia , Ye Juan , Zhang Suzhan
Published: April 2015

Objective

Increasing evidence suggests that cancer-associated inflammation is associated with poor prognosis in patients with cancer. The role of the neutrophil–lymphocyte ratio (NLR) as a predictor in renal cell carcinoma (RCC) remains controversial. We conducted the meta-analysis to determine the association between NLR and clinical outcome of patients with RCC.

Methods and materials

Studies were identified from PubMed and EMBASE databases in March 2014. Meta-analysis was performed to generate combined HRs with 95% CIs for overall survival (OS) and recurrence-free/progress-free survival (RFS/PFS).

Results

15 cohorts containing 3357 patients were included. Our analysis results indicated that elevated NLR predicted poorer OS (HR=1.82, 95% CI 1.51 to 2.19) and RFS/PFS (HR=2.18, 95% CI 1.75 to 2.71) in patients with RCC. These findings were robust when stratified by study region, sample size, therapeutic intervention, types of RCC and study quality. However, it differed significantly by assessment of the cut-off value defining ‘elevated NLR’ in RFS/PFS (p=0.004). The heterogeneity in our meta-analysis was mild to moderate.

Conclusions

Elevated NLR indicates a poorer prognosis for patients with RCC. NLR should be monitored in patients with RCC for rational risk stratification and treatment individualisation.
What the public knows and wants to know about medicines research and development: a survey of the general public in six European countries
Authors: Parsons Suzanne , Starling Bella , Mullan-Jensen Christine , Tham Su-Gwan , Warner Kay , Wever Kim
Published: April 2015

Objectives

To explore public knowledge of, and interest in, learning more about medicines R&D in six European countries.

Design

Online survey of 6931 members of the public across Europe.

Methods

The survey formed part of a public omnibus survey. A quota sampling approach was used with quotas set according to national census data on age, gender and government region. The survey explored the public's knowledge and awareness of medicines R&D, their interest in learning more and the perceived influences on this.

Results

The survey was completed by 6931 members of the public, over 75% of whom reported having no or less than good knowledge of medicines R&D. Males were more likely than females to report good knowledge (17% vs 15%), and knowledge appeared to decrease with age. Those who were currently or had previously been involved in medical research were almost five times more likely to report good knowledge of medicines R&D overall (43% vs 13%). Participants reported good knowledge of medicines safety and clinical trials but little knowledge of pharmacoeconomics. They were most interested in learning more about medicines safety and personalised and predictive medicine and least interested in pharmacoeconomics. Older people, women and respondents with current good knowledge of medicines R&D were most interested in learning more about medicines R&D.

Conclusions

Experience of medical research appears to play a key role in increasing public awareness of and future interest in medicines R&D. Some groups may need to be specifically targeted to increase their awareness of medicines R&D, for example, women expressed great interest in learning more but reported less knowledge than men. It may be useful to explore further the views of those who are currently uninterested in learning more.
Hydrogen sulfide and traffic-related air pollutants in association with increased mortality: a case-crossover study in Reykjavik, Iceland
Authors: Finnbjornsdottir Ragnhildur Gudrun , Oudin Anna , Elvarsson Bjarki Thor , Gislason Thorarinn , Rafnsson Vilhjalmur
Published: April 2015

Objectives

To study the association between daily mortality and short-term increases in air pollutants, both traffic-related and the geothermal source-specific hydrogen sulfide (H2S).

Design

Population-based, time stratified case-crossover. A lag time to 4 days was considered. Seasonal, gender and age stratification were calculated. Also, the best-fit lag when introducing H2S >7 µg/m3was selected by the Akaike Information Criterion (AIC).

Setting

The population of the greater Reykjavik area (n=181 558) during 2003–2009.

Participants

Cases were defined as individuals living in the Reykjavik capital area, 18 years or older (N=138 657), who died due to all natural causes (ICD-10 codes A00-R99) other than injury, poisoning and certain other consequences of external causes, or cardiovascular disease (ICD-10 codes I00-I99) during the study period.

Main outcome measure

Percentage increases in risk of death (IR%) following an interquartile range increase in pollutants.

Results

The total number of deaths due to all natural causes was 7679 and due to cardiovascular diseases was 3033. The interquartile range increased concentrations of H2S (2.6 µg/m3) were associated with daily all natural cause mortality in the Reykjavik capital area. The IR% was statistically significant during the summer season (lag 1: IR%=5.05, 95% CI 0.61 to 9.68; lag 2: IR%=5.09, 95% CI 0.44 to 9.97), among males (lag 0: IR%=2.26, 95% CI 0.23 to 4.44), and among the elderly (lag 0: IR%=1.94, 95% CI 0.12 to 1.04; lag 1: IR%=1.99, 95% CI 0.21 to 1.04), when adjusted for traffic-related pollutants and meteorological variables. The traffic-related pollutants were generally not associated with statistical significant IR%s.

Conclusions

The results suggest that ambient H2S air pollution may increase mortality in Reykjavik, Iceland. To the best of our knowledge, ambient H2S exposure has not previously been associated with increased mortality in population-based studies and therefore the results should be interpreted with caution. Further studies are warranted to confirm or refute whether H2S exposure induces premature deaths.
A cross sectional study of surgical training among United Kingdom general practitioners with specialist interests in surgery
Authors: Ferguson H J M , Fitzgerald J E F , Reilly J , Beamish A J , Gokani V J
Published: April 2015

Objectives

Increasing numbers of minor surgical procedures are being performed in the community. In the UK, general practitioners (family medicine physicians) with a specialist interest (GPwSI) in surgery frequently undertake them. This shift has caused decreases in available cases for junior surgeons to gain and consolidate operative skills. This study evaluated GPwSI's case-load, procedural training and perceptions of offering formalised operative training experience to surgical trainees.

Design

Prospective, questionnaire-based cross-sectional study.

Setting/participants

A novel, 13-item, self-administered questionnaire was distributed to members of the Association of Surgeons in Primary Care (ASPC). A total 113 of 120 ASPC members completed the questionnaire, representing a 94% response rate. Respondents were general practitioners practising or intending to practice surgery in the community.

Results

Respondents performed a mean of 38 (range 5–150) surgical procedures per month in primary care. 37% (42/113) of respondents had previously been awarded Membership or Fellowship of a Surgical Royal College; 22% (25/113) had completed a surgical certificate or diploma or undertaken a course of less than 1 year duration. 41% (46/113) had no formal British surgical qualifications. All respondents believed that surgical training in primary care could be valuable for surgical trainees, and the majority (71/113, 63%) felt that both general practice and surgical trainees could benefit equally from such training.

Conclusions

There is a significant volume of surgical procedures being undertaken in the community by general practitioners, with the capacity and appetite for training of prospective surgeons in this setting, providing appropriate standards are achieved and maintained, commensurate with current standards in secondary care. Surgical experience and training of GPwSI's in surgery is highly varied, and does not yet benefit from the quality assurance secondary care surgical training in the UK undergoes. The Royal Colleges of Surgery and General Practice are well placed to invest in such infrastructure to provide long-term, high-quality service and training in the community.
CareTrack Kids—part 1. Assessing the appropriateness of healthcare delivered to Australian children: study protocol for clinical indicator development
Authors: Wiles Louise K , Hooper Tamara D , Hibbert Peter D , White Les , Mealing Nicole , Jaffe Adam , Cowell Christopher T , Harris Mark F , Runciman William B , Goldstein Stan , Hallahan Andrew R , Wakefield John G , Murphy Elisabeth , Lau Annie , Wheaton Gavin , Williams Helena M , Hughes Clifford , Braithwaite Jeffrey
Published: April 2015

Introduction

Despite the widespread availability of clinical guidelines, considerable gaps remain between the care that is recommended (appropriate care) and the care provided. This protocol describes a research methodology to develop clinical indicators for appropriate care for common paediatric conditions.

Methods and analysis

We will identify conditions amenable to population-level appropriateness of care research and develop clinical indicators for each condition. Candidate conditions have been identified from published research; burden of disease, prevalence and frequency of presentation data; and quality of care priority lists. Clinical indicators will be developed through searches of national and international guidelines, and formatted with explicit criteria for inclusion, exclusion, time frame and setting. Experts will review the indicators using a wiki-based approach and modified Delphi process. A formative evaluation of the wiki process will be undertaken.

Ethics and dissemination

Human Research Ethics Committee approvals have been received from Sydney Children's Hospital Network, Children's Health Queensland Hospital and Health Service, and the Women's and Children's Health Network (South Australia). Applications are under review with Macquarie University and the Royal Australian College of General Practitioners. We will submit the results of the study to relevant journals and offer national and international presentations.
CareTrack Kids—part 2. Assessing the appropriateness of the healthcare delivered to Australian children: study protocol for a retrospective medical record review
Authors: Hooper Tamara D , Hibbert Peter D , Mealing Nicole , Wiles Louise K , Jaffe Adam , White Les , Cowell Christopher T , Harris Mark F , Runciman William B , Goldstein Stan , Hallahan Andrew R , Wakefield John G , Murphy Elisabeth , Lau Annie , Wheaton Gavin , Williams Helena M , Hughes Clifford , Braithwaite Jeffrey
Published: April 2015

Introduction

Australian and international clinical practice guidelines are available for common paediatric conditions. Yet there is evidence that there are substantial variations between the guidelines, recommendations (appropriate care) and the care delivered. This paper describes a study protocol to determine the appropriateness of the healthcare delivered to Australian children for 16 common paediatric conditions in acute and primary healthcare settings.

Methods and analysis

A random sample of 6000–8000 medical records representing a cross-section of the Australian paediatric population will be reviewed for appropriateness of care against a set of indicators within three Australian states (New South Wales, Queensland and South Australia) using multistage, stratified sampling. Medical records of children aged <16 years who presented with at least one of the study conditions during 2012 and 2013 will be reviewed.

Ethics and dissemination

Human Research Ethics Committee approvals have been received from the Sydney Children's Hospital Network, Children's Health Queensland Hospital and Health Service and Women's and Children's Hospital Network (South Australia). An application is under review for the Royal Australian College of General Practitioners. The authors will submit the results of the study to relevant journals and offer oral presentations to researchers, clinicians and policymakers at national and international conferences.
Left ventricular diastolic reserve in patients with type 2 diabetes mellitus
Authors: Leung Melissa , Phan Victoria , Whatmough Melinda , Heritier Stephane , Wong Vincent W , Leung Dominic Y
Published: April 2015

Aims

Diastolic reserve is the ability of left ventricular filling pressures to remain normal with exercise. Impaired diastolic reserve may be an early sign of diabetic cardiomyopathy. We aimed to determine whether diastolic reserve differs in type 2 diabetes (DM) compared with non-DM, and to identify clinical, anthropological, metabolic and resting echocardiographic correlates of impaired diastolic reserve in patients with DM.

Methods and results

237 patients (aged 53±11 years, 133 DM, ejection fraction 68±9%) underwent rest and exercise echocardiography. Mitral E and septal e′ were measured at rest, immediately post, and 10 min into recovery. Analysis of covariance (ANCOVA) and binary regression with continuous outcomes were used to model e′ and E/e′ changes with exercise to identify impaired diastolic reserve defined as post-exercise E/e′ ≥15.

After adjusting for baseline differences, patients with DM immediately post-exercise had a lower septal e′, a lower Δe′ (1.2 vs 2.3 cm/s, p=0.006) and a higher Δ septal E/e′ (1.7 vs 0.08, p<0.001) than patients without DM. In patients with normal resting E/e′ of ≤8 (n=130), DM had a significantly higher post-exercise septal E/e′ and a higher Δseptal E/e′ (2.63 vs 0.50, p<0.001). E/e′ in patients with DM remained significantly elevated up to 10 min post-exercise. Hypertension, longer duration of insulin therapy, poorer glycaemic control, worse renal function, larger left atrial volume and lower septal e′ were independent correlates of impaired diastolic reserve in patients with DM.

Conclusions

Patients with DM have impaired diastolic reserve manifest as a blunted e′ response with exercise, persisting into recovery. Clinical, anthropometric, metabolic and echocardiographic correlates of impaired diastolic reserve in patients with DM were identified. An impaired LV diastolic reserve may be the underlying pathophysiological mechanism in patients with DM with unexplained exertional dyspnoea and may allow earlier detection of DM cardiomyopathy.
Estimating the monetary value of the annual productivity gained in patients with early rheumatoid arthritis receiving etanercept plus methotrexate: interim results from the PRIZE study
Authors: Zhang Wei , Bansback Nick , Sun Huiying , Pedersen Ronald , Kotak Sameer , Anis Aslam H
Published: April 2015

Objective

To measure and value the impact of combined etanercept (ETN) and methotrexate (MTX) therapy on work productivity in patients with early rheumatoid arthritis (RA) over 52 weeks.

Methods

MTX- and biological-naïve patients with RA (symptom onset ≤12 months; Disease Activity Score based on a 28-joint count (DAS28) >3.2) received open-label ETN50/MTX for 52 weeks. The Valuation of Lost Productivity (VOLP) questionnaire, measuring paid and unpaid work productivity impacts, was completed approximately every 13 weeks. Bootstrapping methods were used to test changes in VOLP outcomes over time. One-year productivity impacts were compared between responders (DAS28 ≤3.2) at week 13 and non-responders using zero-inflated models for time loss and two-part models for total costs of lost productivity.

Results

196 patients were employed at baseline and had ≥1 follow-up with VOLP. Compared with baseline, at week 52, patients gained 33.4 h per 3 months in paid work and 4.2 h per week in unpaid work. Total monetary productivity gains were €1322 per 3 months. Over the 1-year period, responders gained paid (231 h) and unpaid work loss (122 h) compared with non-responders, which amounted to a gain of €3670 for responders.

Conclusions

This is the first clinical trial to measure and value the impact of biological treatment on all the labour input components that affect overall productivity. Combination therapy with ETN50/MTX was associated with a significant productivity gain for patients with early RA who were still observed at week 52. Over the 1-year treatment period, responders at week 13 suffered significantly less productivity loss than non-responders suggesting this gain was related to treatment response.

Trial registration number

ClinicalTrials.gov numberNCT00913458
A simplified approach to computing flow and bedload along gravel dune-like bedforms
Authors: Attar S. , Li S. Samuel
Published: April 2015

River dunes are important bedforms. Problems associated with the development and evolution of dune bedforms include increased flood risks, channel erosion, and damage to fish habitats. The purpose of this paper is to investigate the near-bed flow structure and bedload transport along gavel dune-like bedforms. The velocity field is computed using a relatively simple multi-layer hydrodynamic model, with a parameterization of flow separation in the leeside of dunes. The computation is of high efficiency and avoids uncertainties caused by flow separation. Fractional transport rates for a sediment mixture of sands and gravel are calculated using surface-based techniques. The computed flow velocities and bed shear stresses are in good comparison with acoustic Doppler velocimeter measurements. Bedload transport is shown to increase non-linearly with distance toward the dune crest and reach the maximum at the crest. This implies that dune-length averaged bed shear stress is not suitable for bedload calculations. At low discharges, the bed shear stress is the limiting factor, resulting in insignificant bedload. At high discharges when the bed shear stress exceeds a threshold, the effect of sediment-grain hiding and sediment-size availability are important for bedload calculations. The discharge–transport relationship is highly non-linear. This paper has demonstrated selective transport and potential dune surface coarsening. The simplified modelling approach has a good potential for application to field conditions.
Modeling height-diameter curves for prediction
Authors: Mehtätalo Lauri , de-Miguel Sergio , Gregoire Timothy G.
Published: April 2015

Individual tree heights are needed in many situations, including estimation of tree volume, dominant height, and simulation of tree growth. However, height measurements are tedious compared to tree diameter measurements, and therefore height–diameter (H–D) models are commonly used for prediction of tree height. Previous studies have fitted H–D models using approaches that include plot-specific predictors in the models and those that do not include them. In both these approaches, aggregation of the observations to sample plots has usually been taken into account through random effects, but this has not always been done. In this paper, we discuss four alternative model formulations and report an extensive comparison of 16 nonlinear functions in this context using a total of 28 datasets. The datasets represent a wide range of tree species, regions, and ecological zones, consisting of about 126 000 measured trees from 3717 sample plots. Specific R-functions for model fitting and prediction were developed to enable such an extensive model fitting and comparison. Suggestions on model selection, model fitting procedures, and prediction are given and interpretation of the predictions from different models are discussed. No uniformly best function, model formulation, or model fitting procedure was found. However, a 2-parameter Näslund and Curtis function provided satisfactory fit in most datasets for the plot-specific H–D relationship. Model fitting and height imputation procedures developed for this study are provided in an R-package for later use.
Predicting tree damage in fragmented landscapes using a wind risk model coupled with an airflow model
Authors: Dupont Sylvain , Ikonen Veli-Pekka , Väisänen Hannu , Peltola Heli
Published: April 2015

Forest mechanistic wind risk models are widely applied on heterogeneous landscapes, whereas their wind load parameterizations are often derived either from homogeneous stand conditions or from simple forest edge conditions. To evaluate the impact of improving the wind flow representation of the mechanistic wind risk model HWIND on tree damage predictions when applied on heterogeneous environments, we coupled HWIND with the airflow model Aquilon. Aquilon provides to HWIND the velocity profiles and the gust factor (deduced from an approach based on the probability distribution of the wind velocity and on the turbulent kinetic energy). HWIND–Aquilon is compared with HWIND alone on different stand configurations of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) comprising newly clearcuts or shelter stands. Although both models showed the same pattern of differences in edge-tree critical wind speeds with differences in clear-cut length and shelter stand height, the model comparison reveals significant differences in the magnitude of critical wind speeds between them. This discrepancy is explained by the wind velocity and gust factor parameterizations used in HWIND alone, as in other wind risk models that exhibit weaknesses in heterogeneous configurations. This result confirms the need for improving the wind flow representation in mechanistic wind risk models when applied to heterogeneous landscapes.
Applications of Algebra for Some Game Theoretic Problems
Authors: Gandhi Ratnik , Chatterji Samaresh
Published: April 2015

In this paper we present applications of polynomial algebra for the problem of computing Nash equilibria of a subclass of finite normal form games.We characterize Nash equilibria of a normal form game as solutions to a system of polynomial equations and define the subclass of games under consideration. We present an algebraic method for deciding membership decision to the subclass of games. A method based on group action to compute all Nash equilibria of the subclass of games is presented with examples to show working of the methods. We also present some related results and discuss properties of the subclass of games.
h-Principle and ϕ-free embeddings in calibrated manifolds
Authors: Ünal İbrahim
Published: April 2015

In this paper, we prove that the h-principle holds for ϕ-free embeddings for coassociative, Cayley and quaternionic calibrations. As a result, we show that for coassocative calibration *φ, an orientable smooth closed 4-manifold N4can be embedded into any G2-manifold M7as *φ-free if the Euler characteristic of N, χ(N) and the signature of N, τ(N) are equal to zero.
Non-energy semi-stable radial solutions
Authors: Villegas Salvador
Published: April 2015

This paper is devoted to the study of semi-stable radial solutions [Formula: see text] of [Formula: see text] in [Formula: see text], where [Formula: see text] and [Formula: see text]. We establish sharp pointwise estimates for such solutions. In addition, we prove that in dimension [Formula: see text], any semi-stable radial weak solution of [Formula: see text], posed in [Formula: see text] with Dirichlet data [Formula: see text], is regular.
Finite-dimensional pointed Hopf algebras over finite simple groups of Lie type II: Unipotent classes in symplectic groups
Authors: Andruskiewitsch Nicolás , Carnovale Giovanna , García Gastón Andrés
Published: April 2015

We show that Nichols algebras of most simple Yetter–Drinfeld modules over the projective symplectic linear group over a finite field, corresponding to unipotent orbits, have infinite dimension. We give a criterion to deal with unipotent classes of general finite simple groups of Lie type and apply it to regular classes in Chevalley and Steinberg groups.
STABILITY AND RESPONSIVENESS OF THE CARDIOVASCULAR SYSTEM UNDER A PHYSIOLOGICALLY INSPIRED BAROREFLEX MODEL
Authors: DUGGENTO ANDREA , TOSCHI NICOLA , CANICHELLA ANTONIO , VANNUCCI ITALO , GUERRISI MARIA
Published: April 2015

We investigate the Seidel–Herzel model of the human baroreflex feedback control mechanism in terms of parameter choices and its ability to mimic heart rate physiology. We show that this model has the potential to be re-parameterized to better mimic features commonly observed in human physiology. We investigate the modification of the RR return maps as a function of parameter values and show that the model exhibits chaotic behavior. Extensive simulations are performed to establish which parameters mostly contribute to model flexibility in terms of observable output, and critical considerations are cast about potential pitfalls in model re-parameterization to mimic health and pathological behaviors. The Seidel–Herzel model is then merged with a detailed 21-compartment model for the vascular bed in order to examine sensitivity of RR dynamics to whole body simulation parameters. Pathological situations are simulated by altering total blood volume, ventricular compliances and baroreflex gains. The RR solutions show bifurcation diagrams typical of chaotic behavior, where the extension of the chaotic regions is in general smaller in simulated pathological states when compared to baseline (healthy) situations. We speculate that, despite the limits of the model and the limitations of the physiological parameterization, a loss of chaotic behavior correlates with the presence of disease-related aberrations.
RANDOM FOREST BASED CLASSIFICATION OF MEDICAL X-RAY IMAGES USING A GENETIC ALGORITHM FOR FEATURE SELECTION
Authors: NEDJAR IMANE , EL HABIB DAHO MOSTAFA , SETTOUTI NESMA , MAHMOUDI SAÏD , CHIKH MOHAMED AMINE
Published: April 2015

Automated classification of medical images is an increasingly important tool for physicians in their daily activities. However, due to its computational complexity, this task is one of the major current challenges in the field of content-based image retrieval (CBIR). In this paper, a medical image classification approach is proposed. This method is composed of two main phases. The first step consists of a pre-processing, where a texture and shape based features vector is extracted. Also, a feature selection approach was applied by using a Genetic Algorithm (GA). The proposed GA uses a kNN based classification error as fitness function, which enables the GA to obtain a combinatorial set of feature giving rise to optimal accuracy. In the second phase, a classification process is achieved by using random Forest classifier and a supervised multi-class classifier based on the support vector machine (SVM) for classifying X-ray images.
NETWORK APPROACHES FOR ANALYSIS AND MODELING OF THE HUMAN METABOLISM
Authors: FONTANAROSA GABRIELE , MENICHETTI GIULIA , GIAMPIERI ENRICO , CASTELLANI GASTONE , MARTINELLI GIOVANNI , REMONDINI DANIEL
Published: April 2015

We describe a novel approach for metabolic network reconstruction in order to switch from the full reaction-metabolite scheme to a more synthetic description at a pathway level. The network thus obtained retains much information of the original model, allowing easier graphical visualizations and multiscale modeling. We apply our approach to the state-of-the-art database of human metabolic network (Recon2): our approach allows different ranking of the network elements based on its topology and on Markov dynamics induced by network structure.
Hydrophilic bioconjugatable trans-AB-porphyrins and peptide conjugates
Authors: Sahin Tuba , Vairaprakash Pothiappan , Borbas K. Eszter , Balasubramanian Thiagarajan , Lindsey Jonathan S.
Published: April 2015

Porphyrins bearing a single bioconjugatable group and a single water-solubilization motif in a trans-AB-architecture (with no other substituents) provide a compact design of value for studies in diverse disciplines. Established synthetic methods have been employed to prepare four new free base porphyrins and one Mn ( III ) chelate. The hydrophilic motif includes 4-N-methylpyridinium, 2,4,6-tris(carboxymethoxy)phenyl, 2,6-bis(phosphonomethoxy)phenyl, and carboxy; the bioconjugatable unit includes carboxy, maleimido, and N-hydroxysuccinimido (NHS) ester. Bioconjugation experiments with a protected porphyrin-diphosphate or unprotected porphyrin-diphosphonate were examined in organic solution or water, respectively. Both approaches were employed to conjugate to the ε-amino group of Lys11 in AcKPV- NH 2, a tripeptide fragment [ Ac -α-MSH(11-13)- NH 2] of melanocyte stimulating hormone, yielding porphyrin-peptide conjugates.
Synthesis of arylsulfanyl-subphthalocyanines and their ring expansion reaction
Authors: Sakamoto Keiichi , Yoshino Satoru , Takemoto Makoto , Sugaya Kazuhiro , Kubo Hitomi , Komoriya Tomoe , Kamei Shinnosuke , Furukawa Shigeki
Published: April 2015

For dye-sensitized solar cells, phthalocyanines require strong absorption of far-red light between 700 and 850 nm because of their high electron transfer efficiency. Nevertheless phthalocyanines lack of affinity to basal plats, they inhibit utilization as dye-sensitized solar cell photosensitizer. Then, subphthalocyanines are used as precursors to prepare asymmetric 3:1 type phthalocyanines using a ring-enlargement technique to give affinity to basal plates. As subphthalocyanines having arylsulfanyl substituents used as a precursor, asymmetric phthalocyanines are expected to have good affinity to basal plates. Spectroscopic properties and electron transfer abilities to synthesize non-peripheral arylsulfanyl-subphthalocyanines were estimated. In addition to prepare as trial, asymmetric 3:1 type phthalocyanine, hexakis[(4-methylphenyl)thio]phthalocyanine, was synthesized from corresponding subphthalocyanine.
Enhanced NOx Gas Sensing Performance Based on Indium-Doped Co(OH)2 Nanowire–Graphene Nanohybrids
Authors: Song Jiabao , Lin Yufei , Kan Kan , Wang Jingchao , Liu Songying , Li Li , Shi Keying
Published: April 2015

In this paper, the In ( OH )3/ Co ( OH )2/ rGO (ICG) nanohybrids have been synthesized via a simple reflux method. It was found that the nanostructures were actually composed of thin nanosheets or nanowires. The addition of indium in Co ( OH )2 on rGO results in increase in the specific area of nanohybrids (105.7m2g-1). That enhanced the gas sensing responses to NO x compared with Co ( OH )2/ rGO significantly. The ICG nanohybrids with the mass ratio of 5:1 (ICG-5) exhibited excellent gas-sensing properties with low detection limit of 0.97ppm and high sensitivity of 75.32% to 97ppm NO x at room temperature (RT). The gas sensor also showed excellent selectivity to NO x when other common gases such as NH 3, CO , C 2 H 2 and H 2 were present. The sensing mechanism could be attributed to the charge carrier concentration of Co ( OH )2 greatly increased by indium doping, which at last encourages the electron transfer during the interaction with gases.
Limiting spectral measures for random matrix ensembles with a polynomial link function
Authors: Miller Steven J. , Swanson Kirk , Tor Kimsy , Winsor Karl
Published: April 2015

Consider the ensembles of real symmetric Toeplitz matrices and real symmetric Hankel matrices whose entries are i.i.d. random variables chosen from a fixed probability distribution p of mean 0, variance 1, and finite higher moments. Previous work on real symmetric Toeplitz matrices shows that the spectral measures, or densities of normalized eigenvalues, converge almost surely to a universal near-Gaussian distribution, while previous work on real symmetric Hankel matrices shows that the spectral measures converge almost surely to a universal non-unimodal distribution. Real symmetric Toeplitz matrices are constant along the diagonals, while real symmetric Hankel matrices are constant along the skew diagonals. We generalize the Toeplitz and Hankel matrices to study matrices that are constant along some curve described by a real-valued bivariate polynomial (other authors refer to the dependencies among the matrix elements as arising from a link function). Using the Method of Moments and an analysis of the resulting Diophantine equations, we show that the spectral measures associated with linear bivariate polynomials converge in probability and almost surely to universal non-semicircular distributions. We prove that for certain choices these limiting distributions approach the semicircle in the limit of large values of the polynomial coefficients. We then prove that the spectral measures associated with the sum or difference of any two real-valued polynomials with different degrees converge in probability and almost surely to a universal semicircular distribution.
Marine C, S and N biogeochemical processes in the redox-stratified early Cambrian Yangtze ocean
Authors: Cai C. , Xiang L. , Yuan Y. , He X. , Chu X. , Chen Y. , Xu C.
Published: April 2015

The temporal change of redox conditions of the Yangtze ocean has been revealed by investigating the Ediacaran–Cambrian transition section at Zhalagou, South China. During the earliest Cambrian, cherts and shales were deposited under an anoxic and ferruginous bottom water with significantly increasing total organic carbon and P contents, and negative shift in kerogen δ
13
C values in the lowest part of the section. Euxinic bottom water conditions occurred during the earliest Cambrian Stage 2, with the surface water dominated by N
2
utilization by cyanobacteria or sulphur bacteria leading to negative kerogen δ
15
N values. During Stage 3, dissolved oxygen and sulphate concentrations were significantly increased, and thus the oxidized surface water and the redox transition zone overlying a euxinic bottom water may have been expanded, resulting in an increase in kerogen δ
15
N increasing to 2–4‰, a decrease in pyrite δ
34
S decreasing to as low as –24.6‰ and differences in δ
34
S values between kerogen and pyrite as high as 37‰. This period coincided with the abrupt appearance of large-body metazoans. Thus, the expanding oxic surface water may have reinforced the evolution of animals or vice versa. Interestingly, kerogen δ
34
S values show negative relationships to FePy/FeHR ratios and pyrite sulphur contents, indicating that they can be used to reflect redox conditions, with the lightest values being obtained from euxinic environments.
Regulation of NHE3 by lysophosphatidic acid is mediated by phosphorylation of NHE3 by RSK2
Authors: No Yi Ran , He Peijian , Yoo Byong Kwon , Yun C. Chris
Published: April 2015

Na+/H+ exchange by Na+/H+ exchanger 3 (NHE3) is a major route of sodium absorption in the intestine and kidney. We have shown previously that lysophosphatidic acid (LPA), a small phospholipid produced ubiquitously by all types of cells, stimulates NHE3 via LPA5 receptor. Stimulation of NHE3 activity by LPA involves LPA5 transactivating EGF receptor (EGFR) in the apical membrane. EGFR activates proline-rich tyrosine kinase 2 (Pyk2) and ERK, both of which are necessary for NHE3 regulation. However, Pyk2 and ERK are regulated by EGFR via independent pathways and appear to converge on an unidentified intermediate that ultimately targets NHE3. The p90 ribosomal S6 kinase (RSK) family of Ser/Thr protein kinases is a known effector of EGFR and ERK. Hence, we hypothesized that RSK may be the convergent effector of Pyk2 and ERK although it is not known whether Pyk2 regulates RSK. In this study, we show that Pyk2 is necessary for the maintenance of phosphoinositide-dependent kinase 1 (PDK1) autophosphorylation, and knockdown of Pyk2 or PDK1 mitigated LPA-induced phosphorylation of RSK and stimulation of NHE3 activity. Additionally, we show that RSK2, but not RSK1, is responsible for NHE3 regulation. RSK2 interacts with NHE3 at the apical membrane domain, where it phosphorylates NHE3. Alteration of S663 of NHE3 ablated LPA-induced phosphorylation of NHE3 and stimulation of the transport activity. Our study identifies RSK2 as a new kinase that regulates NHE3 activity by direct phosphorylation.
Five years of data diuresis: what have WEH learned?
Authors: Sullivan Jennifer C. , Pollock Jennifer S.
Published: April 2015

This year represents the fifth annual Data Diuresis session of the Water and Electrolyte Homeostasis (WEH) section of the American Physiological Society (APS) at the 2015 Experimental Biology meeting. As opposed to taking a single organ approach to the study of physiology, the WEH section employs an integrative approach to encompass how the different organ systems interact to regulate numerous physiological and pathophysiological processes. The goal of this minireview is to highlight the broad spectrum of research themes that were presented over the first five years of Data Diuresis. Presentation topics include (but are not limited to) oxidative stress, inflammation, obesity, pregnancy, and hypertension spanning the brain, heart and vasculature, and kidney. WEH researchers continue to impact and help drive the direction of physiological research across multiple disciplines, leaving us excited to see what the next five years of Data Diuresis will bring.
Central alterations of neuromuscular function and feedback from group III-IV muscle afferents following exhaustive high-intensity one-leg dynamic exercise
Authors: Pageaux Benjamin , Angius Luca , Hopker James G. , Lepers Romuald , Marcora Samuele M.
Published: April 2015

The aims of this investigation were to describe the central alterations of neuromuscular function induced by exhaustive high-intensity one-leg dynamic exercise (OLDE, study 1) and to indirectly quantify feedback from group III-IV muscle afferents via muscle occlusion (MO, study 2) in healthy adult male humans. We hypothesized that these central alterations and their recovery are associated with changes in afferent feedback. Both studies consisted of two time-to-exhaustion tests at 85% peak power output. In study 1, voluntary activation level (VAL), M-wave, cervicomedullary motor evoked potential (CMEP), motor evoked potential (MEP), and MEP cortical silent period (CSP) of the knee extensor muscles were measured. In study 2, mean arterial pressure (MAP) and leg muscle pain were measured during MO. Measurements were performed preexercise, at exhaustion, and after 3 min recovery. Compared with preexercise values, VAL was lower at exhaustion (−13 ± 13%, P < 0.05) and after 3 min of recovery (−6 ± 6%, P = 0.05). CMEParea/Mareawas lower at exhaustion (−38 ± 13%, P < 0.01) and recovered after 3 min. MEParea/Mareawas higher at exhaustion (+25 ± 27%, P < 0.01) and after 3 min of recovery (+17 ± 20%, P < 0.01). CSP was higher (+19 ± 9%, P < 0.01) only at exhaustion and recovered after 3 min. Markers of afferent feedback (MAP and leg muscle pain during MO) were significantly higher only at exhaustion. These findings suggest that the alterations in spinal excitability and CSP induced by high-intensity OLDE are associated with an increase in afferent feedback at exhaustion, whereas central fatigue does not fully recover even when significant afferent feedback is no longer present.
Ultrasound-induced modulation of cardiac rhythm in neonatal rat ventricular cardiomyocytes
Authors: Fleischman Andrew , Vecchio Christopher , Sunny Youhan , Bawiec Christopher R. , Lewin Peter A. , Kresh J. Yasha , Kohut Andrew R.
Published: April 2015

Isolated neonatal rat ventricular cardiomyocytes were used to study the influence of ultrasound on the chronotropic response in a tissue culture model. The beat frequency of the cells, varying from 40 to 90 beats/min, was measured based upon the translocation of the nuclear membrane captured by a high-speed camera. Ultrasound pulses (frequency = 2.5 MHz) were delivered at 300-ms intervals [3.33 Hz pulse repetition frequency (PRF)], in turn corresponding to 200 pulses/min. The intensity of acoustic energy and pulse duration were made variable, 0.02-0.87 W/cm2 and 1–5 ms, respectively. In 57 of 99 trials, there was a noted average increase in beat frequency of 25% with 8-s exposures to ultrasonic pulses. Applied ultrasound energy with a spatial peak time average acoustic intensity (Ispta) of 0.02 W/cm2 and pulse duration of 1 ms effectively increased the contraction rate of cardiomyocytes ( P < 0.05). Of the acoustic power tested, the lowest level of acoustic intensity and shortest pulse duration proved most effective at increasing the electrophysiological responsiveness and beat frequency of cardiomyocytes. Determining the optimal conditions for delivery of ultrasound will be essential to developing new models for understanding mechanoelectrical coupling (MEC) and understanding novel nonelectrical pacing modalities for clinical applications.
Different pools of glutamate receptors mediate sensitivity to ambient glutamate in the cochlear nucleus
Authors: Yang Yang , Xu-Friedman Matthew A.
Published: April 2015

Ambient glutamate plays an important role in pathological conditions, such as stroke, but its role during normal activity is not clear. In addition, it is not clear how ambient glutamate acts on glutamate receptors with varying affinities or subcellular localizations. To address this, we studied “endbulb of Held” synapses, which are formed by auditory nerve fibers onto bushy cells (BCs) in the anteroventral cochlear nucleus. When ambient glutamate was increased by applying the glutamate reuptake inhibitor TFB-TBOA, BCs depolarized as a result of activation of N-methyl-d-aspartate receptors (NMDARs) and group I metabotropic glutamate receptors (mGluRs). Application of antagonists against NMDARs (in 0 Mg2+) or mGluRs caused hyperpolarization, indicating that these receptors were bound by a tonic source of glutamate. AMPA receptors did not show these effects, consistent with their lower glutamate affinity. We also evaluated the subcellular localization of the receptors activated by ambient glutamate. The mGluRs were not activated by synaptic stimulation and thus appear to be exclusively extrasynaptic. By contrast, NMDARs in both synaptic and extrasynaptic compartments were activated by ambient glutamate, as shown using the use-dependent antagonist MK-801. Levels of ambient glutamate appeared to be regulated in a spike-independent manner, and glia likely play a major role. These low levels of ambient glutamate likely have functional consequences, as even low concentrations of TBOA caused significant increases in BC spiking following synaptic stimulation. These results indicate that normal resting potential appears to be poised in the region of maximal sensitivity to small changes in ambient glutamate.
Interactions between rostral and caudal cortical motor areas in the rat
Authors: Deffeyes J. E. , Touvykine B. , Quessy S. , Dancause N.
Published: April 2015

In rats, forelimb movements can be evoked from two distinct cortical regions, the rostral (RFA) and the caudal (CFA) forelimb areas. RFA and CFA have numerous reciprocal connections, and their projections reach several common targets, which allows them to interact at multiple levels of the motor axis. Lesions affecting these areas result in profound and persistent deficits, supporting their essential role for the production of arm and hand movements. Whereas rats are widely used to study motor control and recovery following lesions, little is known as to how cortical motor areas in this model interact to generate movements. To study interactions between RFA and CFA, we used paired-pulse protocols with intracortical microstimulation techniques (ICMS). A conditioning stimulus (C) in RFA was applied simultaneously, or before a test stimulus (T) in CFA. The impact of RFA conditioning on CFA outputs was quantified by recording electromyographic signals (EMG) signals from the contralateral arm muscles. We found that stimulation of RFA substantially modulates the intensity of CFA outputs while only mildly affecting the latency. In general, the effect of RFA conditioning changed from predominantly facilitatory to inhibitory with increasing delays between the C and the T stimulus. However, inspection of individual cortical sites revealed that RFA has a wide range of influence on CFA outputs with each interstimulation delay we used. Our results show that RFA has powerful and complex modulatory effects on CFA outputs that can allow it to play a major role in the cortical control of forelimb movements.
Improvement of Starch Digestion Usingα-Amylase Entrapped in Pectin-Polyvinyl Alcohol Blend
Authors: Cruz Maurício , Fernandes Kátia , Cysneiros Cristine , Nassar Reginaldo , Caramori Samantha
Published: April 2015

Polyvinyl alcohol (PVA) and pectin blends were used to entrapα-amylase (Termamyl) using glutaraldehyde as a cross-linker. The effect of glutaraldehyde concentration (0.25, 0.5, 0.75, 1.0, and 1.25%) on the activity of the immobilized enzyme and rate of enzyme released was tested during a 24 h period. Characteristics of the material, such as scanning electron microscopy (SEM), tensile strength (TS), elongation, and rate of dissolution in water (pH 5.7), ruminal buffering solution (pH 7.0), and reactor containing 0.1 mol L−1sodium phosphate buffer (pH 6.5), were also analyzed. SEM results showed that the surfaces of the pectin/PVA/amylase films were highly irregular and rough. TS values increased as a function of glutaraldehyde concentration, whereas percentage of elongation (%E) decreased. Pectin/PVA/amylase films presented similar values of solubility in the tested solvents. The material obtained with 0.25% glutaraldehyde performed best with repeated use (active for 24 h), in a phosphate buffer reactor. By contrast, the material obtained with 1.25% glutaraldehyde presented higher performance duringin vitrotesting using an artificial rumen. The results suggest that pectin/PVA/amylase is a highly promising material for biotechnological applications.