Desmin integrates the three-dimensional mechanical properties of muscles

Striated muscle is a linear motor whose properties have been defined in terms of uniaxial structures. The question addressed here is what contribution is made to the properties of this motor by extramyofilament cytoskeletal structures that are not aligned in parallel with the myofilaments. This question arose from observations that transverse loads increase muscle force production in diaphragm but not in the hindlimb muscle, thereby indicating the presence of structures that couple longitudinal and transverse properties of diaphragmatic muscle. Furthermore, we find that the diaphragms of null mutants for the cytoskeletal protein desmin show 1) significant reductions in coupling between the longitudinal and transverse properties, indicating for the first time a role for a specific protein in integrating the three-dimensional mechanical properties of muscle, 2) significant reductions in the stiffness and viscoelasticity of muscle, and 3) significant increases in tetanic force production. Thus desmin serves a complex mechanical function in diaphragm muscle by contributing both to passive stiffness and viscoelasticity and to modulation of active force production in a three-dimensional structural network. Our finding changes the paradigm of force transmission among cells by placing our understanding of the function of the cytoskeleton in the context of the structural and mechanical complexity of muscles.     

Efficient lipase-selective synthesis of dilauryl mannoses by simultaneous reaction–extraction system

An efficient method for enzymatic-selective synthesis of dilauryl mannoses was developed using lipase-catalyzed condensation of d-mannose and lauric acid in a simultaneous reaction–extraction system. The highest equilibrium conversion of diesters of 51% (1,6-diester: 14%; 3,6-diester: 18%; 4,6-diester: 19%) and the total conversion of mono and dilauryl mannoses of 76% were achieved at the n-hexane/acetonitrile ratio of 1:1, the molar ratio of lauric acid to mannose of 4:1, 60 g/l molecular sieves and 5 g/l lipase at 50°C for 72 h in 15 ml SRE system. The new system will be important for the synthesis of dilauryl mannoses.     

Incidence,Characteristics and Risk Factors of Acute Kidney Injury among Dengue Patients: A Retrospective Analysis

Background

Dengue induced acute kidney injury (AKI) imposes heavy burden of illness in terms of morbidity and mortality. A retrospective study was conducted to investigate incidence, characteristics, risk factors and clinical outcomes of AKI among dengue patients.

Methodology

A total 667 dengue patients (2008–2013) were retrospectively evaluated and were stratified into AKI and non-AKI groups by using AKIN criteria. Two groups were compared by using appropriate statistical methods.

Results

There were 95 patients (14.2%) who had AKI, with AKIN-I, AKIN-II and AKIN-III in 76.8%, 16.8% and 6.4% patients, respectively. Significant differences (P<0.05) in demographics and clinico-laboratory characteristics were observed between patients with and without AKI. Presence of dengue hemorrhagic fever [OR (95% CI): 8.0 (3.64–17.59), P<0.001], rhabdomyolysis [OR (95% CI): 7.9 (3.04–20.49)], multiple organ dysfunction [OR (95% CI): 34.6 (14.14–84.73), P<0.001], diabetes mellitus [OR (95% CI): 4.7 (1.12–19.86), P = 0.034], late hospitalization [OR (95% CI): 2.1 (1.12–19.86), P = 0.033] and use of nephrotoxic drugs [OR (95% CI): 2.9 (1.12–19.86), P = 0.006] were associated with AKI. Longer hospital stay (>3 days) was also observed among AKI patients (OR = 1.3, P = 0.044). Additionally, 48.4% AKI patients had renal insufficiencies at discharge that were signicantly associated with severe dengue, secondary infection and diabetes mellitus. Overall mortality was 1.2% and all fatal cases had AKI.

Conclusions

The incidence of AKI is high at 14.2% among dengue patients, and those with AKI portended significant morbidity, mortality, longer hospital stay and poor renal outcomes. Our findings suggest that AKI in dengue is likely to increase healthcare burden that underscores the need of clinicians’ alertness to this highly morbid and potentially fatal complication for optimal prevention and management.     

Mixed Convection Flow of Viscoelastic Fluid by a Stretching Cylinder with Heat Transfer

Flow of viscoelastic fluid due to an impermeable stretching cylinder is discussed. Effects of mixed convection and variable thermal conductivity are present. Thermal conductivity is taken temperature dependent. Nonlinear partial differential system is reduced into the nonlinear ordinary differential system. Resulting nonlinear system is computed for the convergent series solutions. Numerical values of skin friction coefficient and Nusselt number are computed and discussed. The results obtained with the current method are in agreement with previous studies using other methods as well as theoretical ideas. Physical interpretation reflecting the contribution of influential parameters in the present flow is presented. It is hoped that present study serves as a stimulus for modeling further stretching flows especially in polymeric and paper production processes.     

Heat Generation/Absorption Effects in a Boundary Layer Stretched Flow of Maxwell Nanofluid: Analytic and Numeric Solutions

Analysis has been done to investigate the heat generation/absorption effects in a steady flow of non-Newtonian nanofluid over a surface which is stretching linearly in its own plane. An upper convected Maxwell model (UCM) has been utilized as the non-Newtonian fluid model in view of the fact that it can predict relaxation time phenomenon which the Newtonian model cannot. Behavior of the relaxations phenomenon has been presented in terms of Deborah number. Transport phenomenon with convective cooling process has been analyzed. Brownian motion “D_b” and thermophoresis effects “D_t” occur in the transport equations. The momentum, energy and nanoparticle concentration profiles are examined with respect to the involved rheological parameters namely the Deborah number, source/sink parameter, the Brownian motion parameters, thermophoresis parameter and Biot number. Both numerical and analytic solutions are presented and found in nice agreement. Comparison with the published data is also made to ensure the validity. Stream lines for Maxwell and Newtonian fluid models are presented in the analysis.     

Effect of Joule Heating and Thermal Radiation in Flow of Third Grade Fluid over Radiative Surface

This article addresses the boundary layer flow and heat transfer in third grade fluid over an unsteady permeable stretching sheet. The transverse magnetic and electric fields in the momentum equations are considered. Thermal boundary layer equation includes both viscous and Ohmic dissipations. The related nonlinear partial differential system is reduced first into ordinary differential system and then solved for the series solutions. The dependence of velocity and temperature profiles on the various parameters are shown and discussed by sketching graphs. Expressions of skin friction coefficient and local Nusselt number are calculated and analyzed. Numerical values of skin friction coefficient and Nusselt number are tabulated and examined. It is observed that both velocity and temperature increases in presence of electric field. Further the temperature is increased due to the radiation parameter. Thermal boundary layer thickness increases by increasing Eckert number.     

Predictors of Two Months Culture Conversion in Multidrug-Resistant Tuberculosis: Findings from a Retrospective Cohort Study

Background

Various studies have reported culture conversion at two months as a predictor of successful treatment outcome in multidrug-resistant tuberculosis (MDR-TB).

Objectives

The present study was conducted with the aim to evaluate the rate and predictors of culture conversion at two months in MDR-TB patients.

Methods

All confirmed pulmonary MDR-TB patients enrolled for treatment at Lady Reading Hospital Peshawar, Pakistan from 1 January to 31 December 2012 and met the inclusion criteria were reviewed retrospectively. Rate and predictors of culture conversion at two months were evaluated.

Results

Eighty seven (53.4%) out of 163 patients achieved culture conversion at two months. In a multivariate analysis lung cavitation at baseline chest X-ray (P = 0.006, OR = 0.349), resistance to ofloxacin (P = 0.041, OR = 0.193) and streptomycin (P = 0.017, OR = 0.295) had statistically significant (P<0.05) negative association with culture conversion at two months.

Conclusion

A reasonable proportion of patients achieved culture conversion at two months. Factors negatively associated with culture conversion at two months can be easily identified either before diagnosis or early in the course of MDR-TB treatment. This may help in better care of individual patients by identifying them early and treating them vigorously.     

Characterization and identification of compost bacteria based on 16S rRNA gene sequencing

The aim of this study was to isolate and characterize bacteria from the compost of fruit and vegetable waste (FVW) for plant growth-promoting (PGP) activities and investigate the pro-active influence of bacterial isolates on wheat growth. Fourteen bacterial strains (RHC-1 to RHC-14) were isolated and purified in tryptic soya agar (TSA). In addition to being biochemically characterized, these bacterial strains were also tested for their PGP traits, such as phosphate (P)-solubilization, nifH gene amplification, indole-3-acetic acid (IAA) quantification and the production of ammonia, oxidase and catalase. Based on 16S rRNA gene sequencing, these bacterial strains were identified as belonging to species of Bacillus, Lysinibacillus, Lysobacter, Staphylococcus, Enterobacter, Pseudomonas and Serratia. All bacterial strains solubilized tri-calcium phosphate and produced IAA. Two bacterial strains RHC-8 (Enterobacter sp.) and RHC-13 (Pseudomonas sp.) solubilized the maximum amount of tri-calcium phosphate, i.e. 486 and 464 μg/ml, respectively. P-solubilization was associated with a significant drop in the pH of the broth culture from an initial pH of 7 to pH 4.43. In addition to P-solubilization and IAA production, six bacterial strains also carried the nifH gene and were further evaluated for their effect on wheat (Triticum aestivum) growth under controlled conditions. All six bacterial strains enhanced wheat growth as compared to uninoculated control plants. Two of the bacterial strains, RHC-8 and RHC-13, identified as Enterobacter aerogenes and Pseudomonas brenneri, respectively, were assessed as potential PGP rhizobacteria due to exhibiting characteristics of four or more PGP traits and enhancing wheat growth though their specific mechanism of action.