Synthesis of branched carbon nanotubes by carbonization of solid polyvinylidene fluoride fibers

Branched carbon nanotubes (b-CNTs) were synthesized by carbonization of polyvinylidene fluoride (PVDF) fibers containing a Pt catalyst. The solid fibrous polymer converted into carbon nanotubes with simultaneous growth of branches on the surface of the tubes during carbonization. The Pt particles were expected to decompose PVDF polymer inside the tubes into volatile carbonaceous species leaving a hollow center, and also to act as catalytic sites for the growth of carbon branches. The resulting b-CNTs had a high degree of graphitization and a large electrochemical surface area, and also showed a possibility as a supporting material for electrocatalysts.     

A promising bioelectrode based on gene of Mycobacterium leprae immobilized onto poly(4‐aminophenol)

A new bioelectrode for gene detection of Mycobacterium leprae, also known as Hansen's bacillus, was produced by immobilizing of single‐stranded DNA (ssDNA) with 78 bases long (specific gene related to Mycobacterium leprae) on graphite electrode modified with poly(4‐aminophenol). This biosensing platform was able to recognize complementary DNA molecules via hybridization process. Hybridization between probe and target was monitored by voltammetry, using ferrocenecarboxyaldehyde as electrochemical DNA hybridization indicator. The hybridization of nucleic acid probe with the DNA target resulted in significant decrease in the oxidation peak current of ferrocenecarboxyaldehyde, indicating greater affinity of this compound for ssDNA than for double‐strand DNA (dsDNA). The linear range of detection for the DNA target was found to be 0.35 – 35 ng/μL. ssDNA hybridization with the DNA target was also investigated by electrochemical impedance spectroscopy (EIS), showing significant modification in Nyquist plot, by modification in electrode surface after addition of the complementary target. The effective immobilization of specific gene of Mycobacterium leprae onto graphite electrode modified with poly(4‐aminophenol) and the detection of the hybridization process with the DNA target, monitored by voltammetry and EIS indicate that this is a new and promising biosensing platform to gene detection of Hansen's bacillus. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Current methods for characterising mixing and flow in microchannels

This article reviews existing methods for the characterisation of mixing and flow in microchannels, micromixers and microreactors. In particular, it analyses the current experimental techniques and methods available for characterising mixing and the associated phenomena in single and multiphase flow. The review shows that the majority of the experimental techniques used for characterising mixing and two-phase flow in microchannels employ optical methods, which require optical access to the flow, or off-line measurements. Indeed visual measurements are very important for the fundamental understanding of the physics of these flows and the rapid advances in optical measurement techniques, like confocal scanning laser microscopy and high resolution stereo micro particle image velocimetry, are now making full field data retrieval possible. However, integration of microchannel devices in industrial processes will require on-line measurements for process control that do not necessarily rely on optical techniques. Developments are being made in the areas of non-intrusive sensors, magnetic resonance techniques, ultrasonic spectroscopy and on-line flow through measurement cells. The advances made in these areas will certainly be of increasing interest in the future as microchannels are more frequently employed in continuous flow equipment for industrial applications.     

NMR and molecular modelling studies on elastase inhibitor-peptides for wound management

Proteases play an important and critical role in the physiological process of wound repair. However, excessive and unregulated release of proteolytic enzymes (e.g., elastase) mediates abnormal degradation of healthy tissues, which leads to inflammatory disorders such as chronic wounds. Thus, it is of therapeutic interest to develop novel synthetic inhibitor-peptides of elastase, which can restore the balance between the free enzyme and the endogenous inhibitors in chronic wounds. In previous works, we have reported two different drug delivery systems to release novel elastase inhibitors to the wound site. In both systems synthetic peptides (KRCCPDTCGIKCL-Pep4 and KRMMPDTMGIKML-Pep4M) based on the primary structure of the endogenous elastase inhibitor, secretory leucocyte protease inhibitor, were used as active material. Phosphorylation of the reported peptides prompts significant structural differences, which reflects in distinct inhibitory capacity towards elastase. These structural modifications were prompted by electrostatic interactions and hydrogen bonds established from the peptide phosphoresidue. The current study was also extended to another synthetic peptide (WCTASVPPQCY-PepBBI) that is based on the reactive loop of another elastase inhibitor, the Bowmen-Birk inhibitor. PepBBI, phosphorylated and non-phosphorylated, displays similar behaviour to Pep4 and Pep4M. The structural modifications reported herein were evaluated by two-dimensional nuclear magnetic resonance and molecular modelling approaches.     

Characteristics of coal upgraded with heavy oils

We investigated the ability of an oil coating to upgrade Indonesian low-rank coal, which has a low ash content and a moisture content of approximately 30%. Proximate and ultimate analyses of the characteristics of coal samples containing different amounts of asphalt (ASP) and palm fatty acid distillate (PFAD) were studied, including the samples’ calorific values, crossing-point temperatures (CPT), specific surface areas, pore sizes, structural changes, and moisture readsorption. The results showed that the 0.5% PFAD-coated coal was the highest quality. This coal showed few physical and chemical changes, and it had a low surface area and a high CPT value.     

ANFIS modeling of surface roughness in abrasive waterjet machining of carbon fiber reinforced plastics

Journal of Mechanical Science and Technology - This study discusses the development of an Adaptive neuro–fuzzy inference system (ANFIS) model for determining the surface roughness (Ra) during...     

A Review of the Design Strategies for Tailored Cathode Catalyst Materials in Rechargeable Li-O2 Batteries

For the purpose of reducing not only the consumption of natural resources, but also the environmental pollution from internal combustion engines, much effort has been dedicated to developing new energy storage systems (ESSs) and electric vehicles (EVs) powered by batteries. There are several stringent requirements, such as high power/energy density, good safety, and high reliability against external environmental abuse. For next-generation batteries to meet these requirements, the development of a new energy conversion system is crucial. Therefore, lithium-oxygen (lithium-O₂) batteries have attracted intensive attention, due to their high theoretical energy density, compared with those of gasoline engines. However, present lithium-O₂ batteries exhibit low round-trip efficiency and cyclic degradation, thus preventing their commercialization as next-generation power sources. This drawback may be attributed to the high thermodynamic stability of discharge products and their intrinsic insulating character, leading to the surge of polarization in oxygen reduction reactions/oxygen evolution reactions (ORRs/OERs). To alleviate cyclic degradation and improve round-trip efficiency, it has been reported that the polarization can be reduced by adopting adequate cathode catalysts, based on their surface structures regulating oxygen adsorption. Here we provide and discuss several design strategies for tailoring catalytic materials from a structural and morphological viewpoint, as well as their effect on discharge products.     

Heart Failure and Atrial Fibrillation: From Basic Science to Clinical Practice

Heart failure (HF) and atrial fibrillation (AF) are two growing epidemics associated with significant morbidity and mortality. They often coexist due to common risk factors and shared pathophysiological mechanisms. Patients presenting with both HF and AF have a worse prognosis and present a particular therapeutic challenge to clinicians. This review aims to appraise the common pathophysiological background, as well as the prognostic and therapeutic implications of coexistent HF and AF.