bluuebunny/crossref_metadata_2025 huggingface dataset:
A retrospective study on the effects of colistin therapy in children with multidrug-resistant Gram-negative bacterial pathogens: impact of HIV status on outcome
Authors: Dimitriades Konstantinos , Morrow Brenda May , Jeena Prakash
Published: October 2013

Background

Nosocomially acquired multidrug-resistant (MDR) Gram-negative bacteria are important contributors to paediatric intensive care unit (PICU) mortality and morbidity, with limited treatment options.

Aim

To investigate the outcomes of all children treated with colistin for infection with MDR Gram-negative bacteria while admitted to PICU.

Methods

Retrospective observational study of 19 months. Primary endpoints were all-cause intensive care unit mortality and safety. Secondary endpoints evaluated clinical and microbiological outcomes. Cases were stratified according to HIV status.

Results

Twenty-seven children received 30 colistin courses during the study period. Eight patients (29.6%) were HIV infected, six (22.2%) were HIV uninfected but exposed, and 11 (40.7%) were HIV uninfected and unexposed. Common MDR Gram-negative bacteria cultured were: Acinetobacter species (n=22, 81.5%), Pseudomonas aeruginosa (n=11, 40.7%) and Klebsiella pneumoniae (n=7, 25.9%). Mortality was 37%, with no significant difference between HIV strata. No adverse drug reactions were noted. A composite clinical improvement was noted in 16 courses (53.3%) of colistin. Only 30% of colistin courses used in HIV-infected children resulted in an improved clinical assessment as compared with 83.3% of courses in HIV-uninfected/unexposed children (p=0.04). In HIV-infected children, five of 10 (50%) courses of colistin showed bacteriological clearance compared to the HIV uninfected/unexposed group where all cases showed bacterial eradication (p=0.02).

Conclusions

HIV-infected children had poorer clinical and bacteriological responses to colistin treatment than HIV uninfected/unexposed. These results require confirmation with prospective studies to determine whether findings are due to poor microbial response, immunodeficiency or repeated reinfections.
Mind the gap: difference between Framingham heart age and real age increases with age in HIV-positive individuals–a clinical cohort study
Authors: Davies Teri-Louise , Gompels Mark , Johnston Sarah , Bovill Begoña , May Margaret T
Published: October 2013

Objectives

To measure the excess risk of cardiovascular disease (CVD) in HIV-positive individuals by comparing ‘heart age’ with real age and to estimate associations of patients’ characteristics with heart age deviation (heart age–real age).

Design

Clinical Cohort Study.

Setting

Bristol HIV clinic, Brecon Unit at Southmead Hospital, Bristol, UK.

Participants

749 HIV-positive adults who attended for care between 2008 and 2011. Median age was 42 years (IQR 35–49), 67% were male and 82% were treated with antiretroviral therapy.

Main outcome measures

We calculated the Framingham 10-year risk of CVD and traced back to ‘heart age’, the age of an individual with the same score but ideal risk factor values. We estimated the relationship between heart age deviation and real age using fractional polynomial regression. We estimated crude and mutually adjusted associations of sex, age, CD4 count, viral load/treatment status and period of starting antiretroviral therapy with heart age deviation.

Results

The average heart age for a male aged 45 years was 48 years for a non-smoker and 60 years for a smoker. Heart age deviation increased with real age and at younger ages was smaller for females than males, although this reversed after 48 years. Compared to patients with CD4 count <500 cells/mm3, heart age deviation was 2.4 (95% CI 0.7 to 4.0) and 4.3 (2.3 to 6.3) years higher for those with CD4 500–749 cells/mm3and ≥750 cells/mm3, respectively.

Conclusions

In HIV-positive individuals, the difference between heart age and real age increased with age and CD4 count and was very dependent on smoking status. Heart age could be a useful tool to communicate CVD risk to patients and the benefits of stopping smoking.
Treadmill walking speed and survival prediction in men with cardiovascular disease: a 10-year follow-up study
Authors: Chiaranda Giorgio , Bernardi Eva , Codecà Luciano , Conconi Francesco , Myers Jonathan , Terranova Francesco , Volpato Stefano , Mazzoni Gianni , Grazzi Giovanni
Published: October 2013

Objective

To determine whether the walking speed maintained during a 1 km treadmill test at moderate intensity predicts survival in patients with cardiovascular disease.

Design

Population-based prospective study.

Setting

Outpatient secondary prevention programme in Ferrara, Italy.

Participants

1255 male stable cardiac patients, aged 25–85 years at baseline.

Main outcome measures

Walking speed maintained during a 1 km treadmill test, measured at baseline and mortality over a median follow-up of 8.2 years.

Results

Among 1255 patients, 141 died, for an average annual mortality of 1.4%. Of the variables considered, the strongest predictor of all-cause mortality was walking speed (95% CI 0.45 to 0.75, p<0.0001). Based on the average speed maintained during the test, participants were subdivided into quartiles and mortality risk adjusted for confounders was calculated. Compared to the slowest quartile (average walking speed 3.4 km/h), the relative mortality risk decreased for the second, third and fourth quartiles (average walking speed 5.5 km/h), with HRs of 0.73 (95% CI 0.46 to 1.18); 0.54 (95% CI 0.31 to 0.95) and 0.20 (95% CI 0.07 to 0.56), respectively (p for trend <0.0001). Receiver operating curve analysis showed an area under the curve of 0.71 (p<0.0001) and the highest Youden index (0.35) for a walking speed of 4.0 km/h.

Conclusions

The average speed maintained during a 1 km treadmill walking test is inversely related to survival in patients with cardiovascular disease and is a simple and useful tool for stratifying risk in patients undergoing secondary prevention and cardiac rehabilitation programmes.
Loss to follow-up occurs at all stages in the diagnostic and follow-up period among HIV-infected patients in Guinea-Bissau: a 7-year retrospective cohort study
Authors: Hønge Bo Langhoff , Jespersen Sanne , Nordentoft Pernille Bejer , Medina Candida , da Silva David , da Silva Zacarias José , Østergaard Lars , Laursen Alex Lund , Wejse Christian ,   for the Bissau HIV cohort study group
Published: October 2013

Objectives

To describe loss to follow-up (LTFU) at all stages of the HIV programme.

Design

A retrospective cohort study.

Setting

The HIV clinic at Hospital National Simão Mendes in Bissau, Guinea-Bissau.

Participants

A total of 4080 HIV-infected patients.

Outcome measures

Baseline characteristics, percentages and incidence rates of LTFU as well as LTFU risk factors at four different stages: immediately after HIV diagnosis (stage 1), after the first CD4 cell count and before a follow-up consultation (stage 2), after a follow-up consultation for patients not eligible for antiretroviral treatment (ART; stage 3) and LTFU among patients on ART (stage 4).

Results

Almost one-third of the patients were lost to the programme before the first consultation where ART initiation is decided; during the 7-year observation period, more than half of the patients had been lost to follow-up (overall incidence rate=51.1 patients lost per 100 person-years). Age below 30 years at inclusion was a risk factor for LTFU at all stages of the HIV programme. The biggest risk factors were body mass index <18.5 kg/m2(stage 1), male gender (stage 2), HIV-2 infection (stage 3) and CD4 cell count <200 cells/μL (stage 4).

Conclusions

In this study, LTFU constituted a major problem, and this may apply to other similar ART facilities. More than half of the patients were lost to follow-up shortly after enrolment, possibly implying a high mortality. Thus, retention should be given a high priority.
Cross-sectional survey: risk-averse French GPs use more rapid-antigen diagnostic tests in tonsillitis in children
Authors: Michel-Lepage Audrey , Ventelou Bruno , Nebout Antoine , Verger Pierre , Pulcini Céline
Published: October 2013

Objectives

We tested the following hypotheses: (1) risk-averse general practitioners (GPs) might use more Rapid Antigen Diagnostic Tests (RADTs) in tonsillitis in children, probably to decrease their diagnostic uncertainty regarding the aetiology of the disease (viral vs due to group AStreptococcus); and (2) GPs not using RADT might prescribe more antibiotics when they are risk averse.

Design, setting and participants

We conducted a cross-sectional survey of a nationwide French representative sample of 1093 GPs in 2012.

Outcome measures

Multivariate analyses adjusted on the four stratification variables (age, gender, location and volume of activity, ie, the number of annual consultations) were performed to identify the risk domains associated with indicators of good or poor practice.

Results

69.4% of GPs were aware of national guidelines regarding tonsillitis and declared that they had taken these guidelines into account for their last paediatric tonsillitis case. 59.1% declared they used RADT in their last patient aged between 3 and 16 years presenting with tonsillitis; 29.7% of these tests were positive. Among the GPs who used RADT, 30.7% prescribed an antibiotic; 98.3% did either prescribe an antibiotic because of a positive RADT result, or did not prescribe an antibiotic in view of a negative result. Among the GPs who did not use RADT, 50.7% prescribed an antibiotic. In multivariate analyses, risk-averse GPs declared being more aware of and compliant with guidelines (OR=1.56, p<0.01), and used RADTs more often for their last patient (OR=1.30, p<0.05). Among GPs not using RADT in their last patient, risk-averse GPs prescribed more antibiotics compared with risk-tolerant doctors (OR=1.18, p<0.05).

Conclusions

Individual risk attitudes influenced GPs’ practices in tonsillitis, particularly the use of RADTs and antibiotic prescriptions.
Associations between antinuclear antibody staining patterns and clinical features of systemic lupus erythematosus: analysis of a regional Swedish register
Authors: Frodlund Martina , Dahlström Örjan , Kastbom Alf , Skogh Thomas , Sjöwall Christopher
Published: October 2013

Objective

Antinuclear antibody (ANA) analysis by immunofluorescence (IF) microscopy remains a diagnostic hallmark of systemic lupus erythematosus (SLE). The clinical relevance of ANA fine-specificities in SLE has been addressed repeatedly, whereas studies on IF-ANA staining patterns in relation to disease manifestations are very scarce. This study was performed to elucidate whether different staining patterns associate with distinct SLE phenotypes.

Design

Observational cohort study.

Setting

One university hospital rheumatology unit in Sweden.

Participants

The study population consisted of 222 cases (89% women; 93% Caucasians), where of 178 met ≥4/11 of the 1982 American College of Rheumatology (ACR-82) criteria. The remaining 20% had an SLE diagnosis based on positive IF-ANA (HEp-2 cells) and ≥2 typical organ manifestations at the time of diagnosis (Fries’ criteria).

Outcome measures

The IF-ANA staining patterns homogenous (H-ANA), speckled (S-ANA), combined homogenous and speckled (HS-ANA), centromeric (C-ANA), nucleolar (N-ANA)±other patterns and other nuclear patterns (oANA) were related to disease manifestations and laboratory measures. Antigen-specificities were also considered regarding double-stranded DNA (Crithidia luciliae) and the following extractable nuclear antigens: Ro/SSA, La/SSB, Smith antigen (Sm), small nuclear RNP (snRNP), Scl-70 and Jo-1 (immunodiffusion and/or line-blot technique).

Results

54% of the patients with SLE displayed H-ANA, 22% S-ANA, 11% HS-ANA, 9% N-ANA, 1% C-ANA, 2% oANA and 1% were never IF-ANA positive. Staining patterns among patients meeting Fries’ criteria alone did not differ from those fulfilling ACR-82. H-ANA was significantly associated with the 10th criterion according to ACR-82 (‘immunological disorder’). S-ANA was inversely associated with arthritis, ‘immunological disorder’ and signs of organ damage.

Conclusions

H-ANA is the dominant IF-ANA pattern among Swedish patients with SLE, and was found to associate with ‘immunological disorder’ according to ACR-82. The second most common pattern, S-ANA, associated negatively with arthritis and organ damage.
Effects of tanshinone on hyperandrogenism and the quality of life in women with polycystic ovary syndrome: protocol of a double-blind, placebo-controlled, randomised trial
Authors: Shen Wenjuan , Zhang Yuehui , Li Wei , Cong Jing , Zhou Ying , Ng Ernest H Y , Wu Xiaoke
Published: October 2013

Introduction

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in reproductive-age women. Chinese herbal medicine has been used for the treatment of PCOS, but the evidence for its efficacy and safety is minimal. Tanshinones are a class of bioactive molecules isolated fromSalvia miltiorrhiza, a commonly used herb in Traditional Chinese Medicine. This study aims to evaluate the efficacy of tanshinones on hyperandrogenism and quality of life in women with PCOS who do not attempt to conceive.

Methods and analysis

A total of 100 patients will be recruited and randomised into the tanshinone or placebo group. Tanshinone or placebo capsules will be taken orally for 12 weeks. The primary outcome parameter will be a change in plasma testosterone. Secondary end points will be changes in human chorionic gonadotropin-induced androgen response, insulin resistance, reproductive hormones, fasting lipid profiles, oral glucose tolerance test, quality of life and side effects.

Ethics and dissemination

Written informed consent will be obtained from each participant at the time of enrolling in the study. The trial has been approved by the Ethics Committee of First Affiliated Hospital of Heilongjiang University of Chinese Medicine. Results will be disseminated through a publicly accessible website.

Registration details

The study has been registered at the Chinese Clinical Trials Registry (ChiCTR-TRC-12002973) and at clinicaltrials.gov (NCT 01452477).
A prospective cohort study to refine and validate thePanic Screening Scorefor identifying panic attacks associated with unexplained chest pain in the emergency department
Authors: Foldes-Busque Guillaume , Denis Isabelle , Poitras Julien , Fleet Richard P , Archambault Patrick , Dionne Clermont E
Published: October 2013

Introduction

Panic-like anxiety (panic attacks with or without panic disorder), a highly treatable condition, is the most prevalent condition associated with unexplained chest pain in the emergency department. Panic-like anxiety may be responsible for a significant portion of the negative consequences of unexplained chest pain, such as functional limitations and chronicity. However, more than 92% of panic-like anxiety cases remain undiagnosed at the time of discharge from the emergency department. The 4-itemPanic Screening Score(PSS) questionnaire was derived in order to increase the identification of panic-like anxiety in emergency department patients with unexplained chest pain.

Methods and analysis

The goals of this prospective cohort study were to (1) refine the PSS; (2) validate the revised version of the PSS; (3) measure the reliability of the revised version of the PSS and (4) assess the acceptability of the instrument among emergency physicians. Eligible and consenting patients will be administered the PSS in a large emergency department. Patients will be contacted by phone for administration of the criterion standard for panic attacks as well as by a standardised interview to collect information for other predictors of panic attacks. Multivariate analysis will be used to refine the PSS. The new version will be prospectively validated in an independent sample and inter-rater agreement will be assessed in 10% of cases. The screening instrument acceptability will be assessed with theOttawa Acceptability of Decision Rules Instrument.

Ethics and dissemination

This study protocol has been reviewed and approved by the Alphonse-Desjardins research ethics committee. The results of the study will be presented in scientific conferences and published in peer-reviewed scientific journals. Further dissemination via workshops and a dedicated website is planned.
PRImary care Streptococcal Management (PRISM) study: identifying clinical variables associated with Lancefield group A β-haemolytic streptococci and Lancefield non-Group A streptococcal throat infections from two cohorts of patients presenting with an acute sore throat
Authors: Little Paul , Moore Michael , Hobbs F D R , Mant David , McNulty Cliodna , Williamson Ian , Cheng Edith , Stuart Beth , Kelly Joanne , Barnett Jane , Mullee Mark ,   on behalf of the PRISM investigators
Published: October 2013

Objective

To assess the association between features of acute sore throat and the growth of streptococci from culturing a throat swab.

Design

Diagnostic cohort.

Setting

UK general practices.

Participants

Patients aged 5 or over presenting with an acute sore throat. Patients were recruited for a second cohort (cohort 2, n=517) consecutively after the first (cohort 1, n=606) from similar practices.

Main outcome

Predictors of the presence of Lancefield A/C/G streptococci.

Results

The clinical score developed from cohort 1 had poor discrimination in cohort 2 (bootstrapped estimate of area under the receiver operator characteristic (ROC) curve (0.65), due to the poor validity of the individual items in the second data set. Variables significant in multivariate analysis in both cohorts were rapid attendance (prior duration 3 days or less; multivariate adjusted OR 1.92 cohort, 1.67 cohort 2); fever in the last 24 h (1.69, 2.40); and doctor assessment of severity (severely inflamed pharynx/tonsils (2.28, 2.29)). The absence of coryza or cough and purulent tonsils were significant in univariate analysis in both cohorts and in multivariate analysis in one cohort. A five-item score based on Fever, Purulence, Attend rapidly (3 days or less), severely Inflamed tonsils and No cough or coryza (FeverPAIN) had moderate predictive value (bootstrapped area under the ROC curve 0.73 cohort 1, 0.71 cohort 2) and identified a substantial number of participants at low risk of streptococcal infection (38% in cohort 1, 36% in cohort 2 scored ≤1, associated with a streptococcal percentage of 13% and 18%, respectively). A Centor score of ≤1 identified 23% and 26% of participants with streptococcal percentages of 10% and 28%, respectively.

Conclusions

Items widely used to help identify streptococcal sore throat may not be the most consistent. A modified clinical scoring system (FeverPAIN) which requires further validation may be clinically helpful in identifying individuals who are unlikely to have major pathogenic streptococci.
Influence of streamside buffers on stream temperature response following clear-cut harvesting in western Oregon
Authors: Cole Elizabeth , Newton Michael
Published: October 2013

Determining the effectiveness of different riparian buffers for mitigating forest-harvesting impacts on stream temperatures continues to be of interest throughout the world. Four small, low or medium elevation streams in managed western Oregon forests were studied to determine how the arrangement and amount of streamside retention strips (buffers) in clear-cut units influenced stream temperatures. Buffers included (i) no tree, (ii) predominantly sun-sided 12 m wide partial, and (iii) two-sided (Best Management Practice, (BMP)) 15–30 m wide buffers. Harvested units alternated with uncut units along 1800–2600 m study reaches. Impacts of harvesting on stream temperatures were determined by time series comparisons of postharvest and preharvest regressions. Trends for daily maximum and mean stream temperature significantly increased after harvest in no tree buffer units. Partial buffers led to slight (<2 °C) or no increased warming. BMP units led to significantly increased warming, slight, or no increased warming. Temperature responses in uncut units appeared to be linked to responses in upstream harvested units. In many instances, when harvested units exhibited significantly higher postharvest trends, lower trends were observed in the uncut units downstream. Stream temperature trends of 7 day moving maxima indicated warming through the no tree buffer units and some of the BMP units. Peaks in maxima were not maintained in downstream units. Stream temperature responses were related to buffer implementation and stream features, relating to cooling and warming.
STRING FIELD THEORY FROM QUANTUM GRAVITY
Authors: CRANE LOUIS
Published: October 2013

Recent work on neutrino oscillations suggests that the three generations of fermions in the standard model are related by representations of the finite group A(4), the group of symmetries of the tetrahedron. Motivated by this, we explore models which extend the EPRL model for quantum gravity by coupling it to a bosonic quantum field of representations of A(4). This coupling is possible because the representation category of A(4) is a module category over the representation categories used to construct the EPRL model. The vertex operators which interchange vacua in the resulting quantum field theory reproduce the bosons and fermions of the standard model, up to issues of symmetry breaking which we do not resolve. We are led to the hypothesis that physical particles in nature represent vacuum changing operators on a sea of invisible excitations which are only observable in the A(4) representation labels which govern the horizontal symmetry revealed in neutrino oscillations. The quantum field theory of the A(4) representations is just the dual model on the extended lattice of the Lie group E6, as explained by the quantum McKay correspondence of Frenkel, Jing and Wang.

The coupled model can be thought of as string field theory, but propagating on a discretized quantum spacetime rather than a classical manifold.
THE EVALUATION OF AN ORE DEPOSIT DEVELOPMENT PROSPECT THROUGH APPLICATION OF THE "GAMES AGAINST NATURE" APPROACH
Authors: KRZAK MARIUSZ
Published: October 2013

Geological-mining projects are usually associated with relatively high risk and uncertainty in many aspects, including geological, mining, ecologic, economic, market, legal and social conditions. A mineral deposit is an underground natural resource and hence it is difficult to unequivocally predict the actual results of its discovery. Depending on the extent of the resource, the operation of the mine can extend to a few decades. It is necessary to conduct investment actions in successive stages and to evaluate the results of the work stage by stage. This reduces the investment risk and facilitates the decision-making process. In this paper, the use of a specific kind of game, the so-called "game against Nature," is suggested before a final decision on deposit development is made. This methodology was tested on the example of one of the zinc-lead ore deposits in the Silesia-Cracow region. Apart from supporting the decision-making process, this methodology offers the means to evaluate further research and costs which may be incurred for obtaining supplementary information related to the ore deposit parameters, specifically its reserves.
A LOW POWER 2.4 GHz RF TRANSCEIVER FOR ZIGBEE APPLICATIONS
Authors: LIU WEIYANG , CHEN JINGJING , WANG HAIYONG , WU NANJIAN
Published: October 2013

This paper presents a low power RF transceiver for 2.4 GHz ZigBee applications. The current reused inductor-less-load balun low noise amplifier (LNA) with quadrature mixer is proposed for area and power saving for low-IF receiver. The transmitter adopts power efficient power amplifier (PA) to improve transmitting efficiency. This RF transceiver is implemented in 0.18 μm CMOS technology. The receiver achieves 6.5 dB noise figure (NF) and 20 dB conversion gain. The transmitter delivers maximum +3 dBm output power with PA efficiency of 30%. The receiver and transmitter front-end dissipate 1.9 mW and 5.3 mW at 1.8 V supply, respectively. The whole die area is 0.95 mm2.
A RE-CONFIGURABLE ARCHITECTURE FOR SWITCHED CAPACITOR SIGMA-DELTA ANALOG-TO-DIGITAL CONVERSION
Authors: WAN KAREN , CHAN GIGI , WONG WILLIAM , WAN KAM CHUEN , YAU BRYCE , WU ANDY , KWONG DAVID , BASCHIROTTO ANDREA
Published: October 2013

A re-configurable switched capacitor sigma-delta analog-to-digital conversion architecture1,2 is proposed. The architecture consists of a MASH sigma delta modulator with nth lower-order (first- or second-order) loops cascaded together. Each loop can be powered on or off operating in high or low performance mode, according to application needs. The architecture can be configured to optimize performance and power consumption for specific resolution and applications. The architecture is proven by means of a prototype, implemented as a fourth-order and fabricated in a standard 0.18 um CMOS technology. The outputs of both high performance mode (fourth-order) and medium performance mode (second-order, first loop ON) are measured to demonstrate the configurability. The FFT demonstrates that the noise shaping for the fourth-order modulator is better than that of the second-order modulator with steeper noise shaping slope.
VCO-BASED CONTINUOUS-TIME SIGMA DELTA ADC BASED ON A DUAL-VCO-QUANTIZER-LOOP STRUCTURE
Authors: XU Z. T. , ZHANG X. L. , CHEN J. Z. , HU S. G. , YU Q. , LIU Y. , LIM W. M.
Published: October 2013

This paper explores a continuous time (CT) sigma delta (ΣΔ) analog-to-digital converter (ADC) based on a dual-voltage-controlled oscillator (VCO)-quantizer-loop structure. A third-order filter is adopted to reduce quantization noise and VCO nonlinearity. Even-order harmonics of VCO are significantly reduced by the proposed dual-VCO-quantizer-loop structure. The prototype with 10 MHz bandwidth and 400 MHz clock rate is designed using a 0.18 μm RF CMOS process. Simulation results show that the signal-to-noise ratio and signal-to-noise distortion ratio (SNDR) are 76.9 and 76 dB, respectively, consuming 37 mA at 1.8 V. The key module of the ADC, which is a 4-bit VCO-based quantizer, can convert the voltage signal into a frequency signal and quantize the corresponding frequency to thermometer codes at 400 MS/s.
A POWER AND AREA EFFICIENT 65 nm CMOS DELAY-LINE ADC FOR ON-CHIP VOLTAGE SENSING
Authors: SHEN SIDA AMY , XIE SHUANG , NG WAI TUNG
Published: October 2013

This paper presents a 4-bit windowed delay-line analog-to-digital converter (ADC) implemented in 65 nm CMOS technology for VLSI dynamic voltage scaling power management applications. Good linearity is achieved in the proposed power and area efficient ADC without the use of resistors for compensation. The circuit performance was analyzed theoretically and verified experimentally. The measured DNL is within ±0.25 LSB and INL ±0.15 LSB. It occupies an area of 0.009 mm2. With a sampling rate of 4 MHz, the ADC consumes 14 μW with an ENOB of 4.1 and voltage sensing range from 0.87 V to 1.32 V.
The Γ-limit for singularly perturbed functionals of Perona–Malik type in arbitrary dimension
Authors: Bellettini Giovanni , Chambolle Antonin , Goldman Michael
Published: October 2013

In this paper, we generalize to arbitrary dimensions a one-dimensional equicoerciveness and Γ-convergence result for a second derivative perturbation of Perona–Malik type functionals. Our proof relies on a new density result in the space of special functions of bounded variation with vanishing diffuse gradient part. This provides a direction of investigation to derive approximation for functionals with discontinuities penalized with a "cohesive" energy, that is, whose cost depends on the actual opening of the discontinuity.
Optimal monodomain approximations of the bidomain equations used in cardiac electrophysiology
Authors: Coudière Yves , Bourgault Yves , Rioux Myriam
Published: October 2013

The bidomain model is the current most sophisticated model used in cardiac electrophysiology. The monodomain model is a simplification of the bidomain model that is less computationally intensive but only valid under equal conductivity ratio. We propose in this paper optimal monodomain approximations of the bidomain model. We first prove that the error between the bidomain and monodomain solutions is bounded by the error ‖B - A‖ between the bidomain and monodomain conductivity operators. Optimal monodomain approximations are defined by minimizing the distance ‖B - A‖, which reduces for solutions over all ℝd to minimize the Lp norm of the difference between the operator symbols. Similarly, comparing the symbols pointwise amounts to compare the propagation of planar waves in the bidomain and monodomain models. We prove that any monodomain model properly propagates at least d planar waves in ℝd. We next consider and solve the optimal problem in the L∞ and L2 norms, the former providing minimal propagation error uniformly over all directions. The quality of these optimal monodomain approximations is compared among themselves and with other published approximations using two sets of test cases. The first one uses periodic boundary conditions to mimic propagation in ℝd while the second is based on a square domain with common Neumann boundary conditions. For the first test cases, we show that the error on the propagation speed is highly correlated with the error on the symbols. The second test cases show that domain boundaries control propagation directions, with only partial impact from the conductivity operator used.
UNBOUNDED TAME QUASIREPRESENTATIONS WITH COMMUTATIVE DISCREPANCIES FOR AMENABLE GROUPS
Authors: SHTERN A. I.
Published: October 2013

Continuing the study of representations of amenable groups, we discuss one of the simplest cases in which a (not necessarily bounded) Banach space quasirepresentation of an amenable group is close to an ordinary representation of the group in the same space.
EVALUATION OF CAPACITY SPECTRUM METHOD IN ESTIMATING SEISMIC DEMANDS OF TRIPLE PENDULUM BEARINGS UNDER NEAR-FIELD GROUND MOTIONS
Authors: AMIRI GHOLAMREZA GHODRATI , NAMIRANIAN PEJMAN
Published: October 2013

Simplified methods for analyzing seismically isolated structures are always used either as a design procedure or as checking criteria for the results of time history procedure. The main purpose of this study is to evaluate the accuracy of one of these methods, the capacity spectrum method (CSM), in predicting the seismic demands, such as isolator displacement and maximum base shear force, of structures with triple pendulum bearings (TPBs) under bidirectional near-field ground motions. By comparing the results of this method with those of the nonlinear time history analysis (NTHA), it can be concluded that the CSM is able to predict the maximum isolator displacement and base shear of the structure with acceptable accuracy. It should be noted that for softer soil site conditions, the values of demand calculated by CSM are sometimes underestimated compared with the results of NTHA, especially when the effective period of system exceeds 3.0 s or when the TPB works on the fifth regime of its pendulum mechanism.
KINETIC CORRELATION IN NON-EQUILIBRIUM FERMION–BOSON GAS
Authors: RAMONAS M. , KATILIUS R. , MATULIONIS A. , GANTSEVICH S. V.
Published: October 2013

We present a theoretic treatment of particle–particle correlation in a non-equilibrium fermion–boson gas subjected to strong electric field. The detailed description is based on an example of hot electrons and hot phonons in a solid under quasi-classical approach in terms of Boltzmann-like kinetic equations. We develop the mathematical apparatus, based on diagrammatic approach, for quantitative investigation of the flows of correlated particles. Non-trivial terms are resolved, and the correlations crucial for electric fluctuations are discussed.
DECOMPOSING MODULES INTO DIRECT SUMS OF COTYPE SUBMODULES
Authors: ALVARADO-GARCÍA ALEJANDRO , RINCÓN-MEJÍA HUGO ALBERTO , RÍOS-MONTES JOSÉ , TOMÉ-ARREOLA BERTHA
Published: October 2013

In this paper, we study the decompositions of an amply supplemented module M into a direct sum of cotype submodules. For this purpose, we introduce some conatural classes, such as the class of all q-molecular modules, the class of all q-bottomless modules, the class of all q-discrete modules and the class of all q-continuous modules, which are defined for every ring. We also find conditions on the structure of the cotype submodules of an amply supplemented module M, in order for M to have certain direct sum decompositions.
COLEMAN AUTOMORPHISMS OF STANDARD WREATH PRODUCTS OF NILPOTENT GROUPS BY GROUPS WITH PRESCRIBED SYLOW 2-SUBGROUPS
Authors: LI ZHENGXING , HAI JINKE
Published: October 2013

Let G = N wr H be the standard wreath product of N by H, where N is a finite nilpotent group and H is a finite group whose Sylow 2-subgroups are either cyclic, dihedral or generalized quaternion. It is shown that every Coleman automorphism of G is inner. As a direct consequence of this result, it is obtained that the normalizer property holds for G.
EFFECT OF FLOW ACCELERATION ON DEFORMATION AND ADHESION DYNAMICS OF CAPTURED CELLS
Authors: HE L. , LUO Z. Y. , XU F. , BAI B. F.
Published: October 2013

Cell deformation and adhesion under shear flows play an important role in both cell migration in vivo and capture based microfluidic devices in vitro. Adhesion dynamics of captured cell (e.g., firm adhesion, cell rolling and cell detachment) under steady shear flows have been studied extensively. However, cell adhesion under accelerating flows is common both in vivo and in vitro, and dynamics of cell adhesion under accelerating flows remains unknown. As such, we used a mathematical model based on the front tracking method and investigated the effect of flow acceleration on deformation and adhesion dynamics of captured cells, including cell deformation index, cell shape evolution, the velocities of cell center, contact time and wall shear stress for cell rolling and detachment by using a series of parameter values for leukocyte. The results showed that the cell presented three dynamics states (i.e., firm adhesion, rolling and detachment) with increasing wall shear stress under uniform flows. Wall shear stresses were < 0.56 Pa and > 1.12 Pa for firm adhesion and detachment, respectively. The wall shear stresses were at the range 1.48–1.63 Pa (higher than 1.12 Pa) when cell left the bottom surface of the channel under flow accelerations (a = 0.975–1.625 m/s2). The minimum of deformation index under accelerating flow was smaller than that under uniform flow. In conclusion, the flow acceleration promotes the deformation and adhesion of captured cells. These findings could further the understanding of cell migration in vivo and promote the development of capture based microfluidic devices in vitro.
Quantum-chemical study on relationship between structure and antioxidant properties of hepatoprotective compounds occurring in Cynara scolymus and Silybum marianum
Authors: Mikulski Damian , Eder Krzysztof , Molski Marcin
Published: October 2013

Accurate quantum computations based on the density functional theory have been performed to study the relationship between the electronic geometry and antioxidant capacity of chlorogenic acid, silybin and all geometric stereoisomers of cynarine, isolated from plant extract of Cynara scolymus and Silybum marianum. To elucidate their antioxidant activity, the HOMO orbital distribution, adiabatic ionization potential (AIP), spin density in free radicals, homolytic dissociation enthalpies (BDE), and proton dissociation enthalpies (PDE) of the O – H bonds have been calculated. For minimum energy conformations, the antioxidative parameters were quantitatively analyzed at the B3LYP/6-311G(d,p) level of theory. The results have shown that the hydrogen transfer mechanism is more preferable in nonpolar medium than in water. From the results obtained we can conclude that SET-PT (single electron transfer followed by proton transfer) is the most preferred mechanism in water medium. The catechol moiety and planar geometry of trans-stilbene and cis-stilbene moieties in cynarine stereoisomers, chlorogenic acid and their phenoxy radicals strongly contribute to enhancement of the antioxidant activity of these compounds. Trans,trans-cynarine appears to be the best candidate for proton and hydrogen atom donor. It has been predicted that cis,cis, trans,cis and cis,trans stereoisomers of cynarine show antioxidant capacity. Our study shows that all of the investigated compounds reveal strong antioxidant activity.
AG NANOPARTICLES-MODIFIED ANATASE TiO2 SINGLE CRYSTALS CUBES FOR IMPROVING PHOTOELECTRIC CONVERSION
Authors: LIANG Y. Q. , CUI Z. D. , ZHU S. L. , LI Z. Y. , YANG X. J.
Published: October 2013

Ag nanoparticles were deposited by polyol process onto the as-synthesized anatase TiO 2 cubes with single crystals by hydrothermal method. The materials were characterized by SEM, XRD, TEM, XPS and UV-vis spectroscopy and their photoconversion efficiencies were also evaluated. The photocurrent measurements revealed that the modification of the anatase TiO 2 cubes with Ag nanoparticles improved the photoelectrochemical properties of electrodes.
NITRITE REMOVAL FROM AQUEOUS SOLUTION USING SURFACE MODIFIED MAGHEMITE NANOPARTICLES
Authors: MIRZAYI BEHRUZ , NEMATOLLAHZADEH ALI , FIROUZNIA FOROUGH , HEYDARI SIMA
Published: October 2013

In the present work, maghemite nanoparticles (MNP) was synthesized by a simplified method and then modified by sodium dodecyl benzene sulfonate (NaDBS) for the removal of nitrite from aqueous solution. The prepared nanoparticles were characterized by Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The SEM image and XRD analysis showed that the average particle size and crystallite of the maghemite nanopaticles are ca. 32.7 nm and 33.5 nm, respectively. Different parameters namely, pH of the adsorption solution, adsorbent dosage and spectrophotometric reagents were optimized. Spectrophotometric determination of nitrite in an optimized condition showed that the MNP is able to deplete over 88% of nitrite from the initial solution. Moreover, dynamic adsorption study per se confirmed the shortest necessary contact time (ca. 6 min) in the adsorption process of nitrite which is quite encouraging from a practical and industrial point of view. The kinematic study revealed that the nitrite adsorption is a pseudo-first-order process. In addition, two different models (Freundlich- and kinetic-type model) were developed for the adsorbent dosage effect on nitrite adsorption. A Freundlich-type model manifested high coefficients of regression, indicating its robustness.
PREPARATION AND PROPERTY STUDIES OF Zn3P2/CALCIUM ALGINATE
Authors: JIANG JIANFANG , CUI HAIXIN , CAO YU
Published: October 2013

Zn 3 P 2 is an acute and effective rodenticide used widely to protect grains in stores and domestically to kill rodents. This study aims to postpone the time of poisoning symptoms after eating Zn 3 P 2 and improve the effect of killing rodents. Zn 3 P 2/calcium alginate ( Zn 3 P 2/ CA ) was synthesized through the reaction of sodium alginate and calcium chloride by the reversed-phase microemulsion method and then loaded with Zn 3 P 2 technical. It was characterized by X-ray diffractometer, laser particle size analyzer, scanning electron microscope (SEM) and transmission electron microscopy (TEM). The drug loading capacity, slow-controlled release performances and toxic effects were also investigated. The results showed that Zn 3 P 2/ CA was spherical, average particle size was 353.9 nm, and particle dispersion index (PDI) was 0.195. The mass ratios of calcium alginate and Zn 3 P 2 technical ( CA / Zn 3 P 2) had significant impacts to drug loading capacity and slow-controlled release performances of Zn 3 P 2/ CA . The palatability and efficacy of Zn 3 P 2/ CA were significantly improved and enhanced compared with Zn 3 P 2 technical. The results showed that Zn 3 P 2/ CA presented high loading efficiency, commendable sustained-release performance and good environmental compatibility, and this delivery carrier may be extended to other slow-controlled release and high-efficient pesticide formulation in future.
SYNTHESIS, CHARACTERIZATION, CONTROLLED RELEASE AND CYTOTOXIC EFFECT OF ANTHRANILIC ACID-LOADED CHITOSAN AND POLYETHYLENE GLYCOL-MAGNETIC NANOPARTICLES ON MURINE MACROPHAGE RAW 264.7 CELLS
Authors: HUSSEIN-AL-ALI SAMER HASAN , ARULSELVAN PALANISAMY , HUSSEIN MOHD ZOBIR , FAKURAZI SHARIDA , ISMAIL MAZNAH , DORNIANI DENA , EL ZOWALATY MOHAMMAD EZZAT
Published: October 2013

Magnetic nanoparticles (MNPs) were prepared by the coprecipitation method using a molar ratio of Fe 3+: Fe 2+ of 2:1. The surface of MNP was coated with chitosan (CS) and polyethylene glycol (PEG) to form CS–MNP and PEG–MNP nanoparticles, respectively. Anthranilic acid (AA) was loaded on the surface of the resulting nanoparticles to form AA–CS–MNP and AA–PEG–MNP nanocomposites, respectively. The nanocomposites obtained were characterized using powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetry analysis (TGA), vibrating sample magnetometer (VSM) and scanning electron microscopy (SEM). XRD results showed that the as-synthesized nanocomposites are pure magnetite. FTIR results analysis indicated the existence of two polymers on the particle surface of the MNP and the presence of loaded AA on the surface of CS–MNP and PEG–MNP nanoparticles. Anthranilic acid loading and the release profiles of AA–CS–MNP and AA–PEG–MNP nanocomposites showed that up to 8.8% and 5.5% of the adsorbed drug were released in 670 min and 771 min, respectively. Anthranilic acid release profiles followed a pseudo-second-order kinetic controlled process. The cytotoxicity of the as-synthesized anthranilic acid nanocomposities were determined using MTT assay using murine macrophage RAW 264.7 cells. MTT results showed that the cytotoxic effects of AA–CS–MNP were higher than AA–PEG–MNP against the tested cells as compared to free anthranilic acid. In this manner, this study introduces novel anthranilic acid nanocomposites that can be used on-demand for biomedical applications.
MULTISTAGE DYNAMIC SYSTEM OF MICROBIAL BATCH FERMENTATION AND ITS PARAMETER IDENTIFICATION
Authors: WANG YAN , LI XIAOHONG , FENG ENMIN , XIU ZHILONG
Published: October 2013

Based on 1,3-propanediol production from batch fermentation of glycerol by Klebsiella pneumoniae, a multistage dynamic system and its parameter identification are discussed in this paper. The batch fermentation process is divided into three stages exhibiting different dynamic behaviors and characteristics, from which a corresponding nonlinear multistage dynamic system is built. We then propose a parameter identification optimization model whose objective function is the average relative error. The model is solved by particle swarm optimization weighted by inertia, and the result shows that the relative error of our proposed model is 2–10% smaller than those of existing models.
FIBONACCI MATRICES AND HYBRID MATRIX CRYPTOGRAPHY
Authors: PRASAD BANDHU
Published: October 2013

In this paper, we develop hybrid matrix cryptography followed by Fibonacci Qp,h(x) matrix, where h(x) is a polynomial with real coefficients and p = 1, 2, 3, …. They are the generalization of classical Fibonacci Q matrix for a continuous domain. They are used for designing super reliable cryptosystems.
A Global Attractor in Some Discrete Contest Competition Models with Delay under the Effect of Periodic Stocking
Authors: AlSharawi Ziyad
Published: October 2013

We consider discrete models of the formxn+1=xnf(xn−1)+hn, wherehnis a nonnegativep-periodic sequence representing stocking in the population, and investigate their dynamics. Under certain conditions on the recruitment functionf(x), we give a compact invariant region and use Brouwer fixed point theorem to prove the existence of ap-periodic solution. Also, we prove the global attractivity of thep-periodic solution whenp=2. In particular, this study gives theoretical results attesting to the belief that stocking (whether it is constant or periodic) preserves the global attractivity of the periodic solution in contest competition models with short delay. Finally, as an illustrative example, we discuss Pielou's model with periodic stocking.
Animal Models of Diabetic Retinopathy: Summary and Comparison
Authors: Lai Angela Ka Wai , Lo Amy C. Y.
Published: October 2013

Diabetic retinopathy (DR) is a microvascular complication associated with chronic exposure to hyperglycemia and is a major cause of blindness worldwide. Although clinical assessment and retinal autopsy of diabetic patients provide information on the features and progression of DR, its underlying pathophysiological mechanism cannot be deduced. In order to have a better understanding of the development of DR at the molecular and cellular levels, a variety of animal models have been developed. They include pharmacological induction of hyperglycemia and spontaneous diabetic rodents as well as models of angiogenesis without diabetes (to compensate for the absence of proliferative DR symptoms). In this review, we summarize the existing protocols to induce diabetes using STZ. We also describe and compare the pathological presentations, in both morphological and functional aspects, of the currently available DR animal models. The advantages and disadvantages of using different animals, ranging from zebrafish, rodents to other higher-order mammals, are also discussed. Until now, there is no single model that displays all the clinical features of DR as seen in human. Yet, with the understanding of the pathological findings in these animal models, researchers can select the most suitable models for mechanistic studies or drug screening.
Nonlinear Hydroelastic Waves beneath a Floating Ice Sheet in a Fluid of Finite Depth
Authors: Wang Ping , Cheng Zunshui
Published: October 2013

The nonlinear hydroelastic waves propagating beneath an infinite ice sheet floating on an inviscid fluid of finite depth are investigated analytically. The approximate series solutions for the velocity potential and the wave surface elevation are derived, respectively, by an analytic approximation technique named homotopy analysis method (HAM) and are presented for the second-order components. Also, homotopy squared residual technique is employed to guarantee the convergence of the series solutions. The present formulas, different from the perturbation solutions, are highly accurate and uniformly valid without assuming that these nonlinear partial differential equations (PDEs) have small parameters necessarily. It is noted that the effects of water depth, the ice sheet thickness, and Young’s modulus are analytically expressed in detail. We find that, in different water depths, the hydroelastic waves traveling beneath the thickest ice sheet always contain the largest wave energy. While with an increasing thickness of the sheet, the wave elevation tends to be smoothened at the crest and be sharpened at the trough. The larger Young’s modulus of the sheet also causes analogous effects. The results obtained show that the thickness and Young’s modulus of the floating ice sheet all greatly affect the wave energy and wave profile in different water depths.
Footstep and Vehicle Detection Using Seismic Sensors in Wireless Sensor Network: Field Tests
Authors: Koç Gökhan , Yegin Korkut
Published: October 2013

Extensive field tests were carried out to assess the performance of adaptive thresholds algorithm for footstep and vehicle detection using seismic sensors. Each seismic sensor unit is equipped with wireless sensor node to communicate critical data to sensor gateway. Results from 92 different test configurations were analyzed in terms of detection and classification. Hit and false alarm rates of classification algorithm were formed, and detection ranges were determined based on these results. Amplification values of low-intensity seismic data were also taken into account in the analysis. Algorithm-dependent constants such as adaptive thresholds sample sizes were examined for performance. Detection and classification of seismic signals due to footstep, rain, or vehicle were successfully performed.