Efficient electrocatalysis of L-cysteine oxidation at carbon ionic liquid electrode

The electrochemistry of L-cysteine (CySH) in neutral aqueous media was investigated using carbon ionic liquid electrode (CILE). Comparative experiments were carried out using glassy carbon electrodes. At CILE, highly reproducible and well-defined cyclic voltammograms were obtained for l-cysteine with a peak potential of 0.49V vs Ag/AgCl, showing that CILE manifests a good electrocatalytic activity toward oxidation of l-cysteine. A linear dynamic range of 2-210microM with an experimental detection limit of 2microM was obtained. The method was successfully applied to the determination of l-cysteine in a sample of soya milk. Cysteine oxidation at CILE does not result in deactivation of the electrode surface. Mechanistic studies showed that, at CILE, the overall CySH oxidation is controlled by the oxidation of the CyS(-) electroactive species.     

Nerve regeneration with aid of nanotechnology and cellular engineering

Repairing nerve defects with large gaps remains one of the most operative challenges for surgeons. Incomplete recovery from peripheral nerve injuries can produce a diversity of negative outcomes, including numbness, impairment of sensory or motor function, possibility of developing chronic pain, and devastating permanent disability. In the last few years, numerous microsurgical techniques, such as coaptation, nerve autograft, and different biological or polymeric nerve conduits, have been developed to reconstruct a long segment of damaged peripheral nerve. A few of these techniques are promising and have become popular among surgeons. Advancements in the field of tissue engineering have led to development of synthetic nerve conduits as an alternative for the nerve autograft technique, which is the current practice to bridge nerve defects with gaps larger than 30 mm. However, to date, despite significant progress in this field, no material has been found to be an ideal alternative to the nerve autograft. This article briefly reviews major up-to-date published studies using different materials as an alternative to the nerve autograft to bridge peripheral nerve gaps in an attempt to assess their ability to support and enhance nerve regeneration and their prospective drawbacks, and also highlights the promising hope for nerve regeneration with the next generation of nerve conduits, which has been significantly enhanced with the tissue engineering approach, especially with the aid of nanotechnology in development of the three-dimensional scaffold. The goal is to determine potential alternatives for nerve regeneration and repair that are simply and directly applicable in clinical conditions.     

Effects of type of binder and conducting phase on the performance of solid‐state electrochemiluminescence composites

The electrochemiluminescence (ECL) of tris(2,2‐bipyridyl)ruthenium [Ru(bpy)₃]²⁺ has received much attention. By immobilizing [Ru(bpy)₃]²⁺ on an electrode surface, solid‐state ECL has several advantages over solution‐phase ECL, such as reduced amounts of costly reagent and a simplified experimental design. Herein, different types of solid‐state ECL sensors were fabricated and the performances of paraffin oil and two ionic liquids (ILs) as the binders were compared for the construction of solid‐state ECL. Scanning electron microscopy (SEM), CCD camera, UV–vis, fluorescence spectroscopy, electrochemistry and ECL were applied to characterize and evaluate the performance of the solid‐state composites. According to the obtained results, Ru–graphite/IL octyl pyridinium hexaflurophosphate (OPPF₆) was introduced as a new solid‐state ECL with excellent properties such as simple preparation, low background current, fast electron‐transfer rate and good reproducibility and stability. Moreover, for a study of the effect of carbon structure on the performance of the electrode, graphite was replaced by multi‐walled carbon nanotubes (MWCNTs) and Ru–MWCNT/OPPF₆ was constructed and its efficiency was compared with Ru–graphite/OPPF₆ composite electrode. Copyright © 2013 John Wiley & Sons, Ltd.     

Improving the accumulation of recombinant human serum albumin (HSA) in transgenic tobacco plants by fusion with the N-terminal proline-rich domain of γ-zein (Zera)

In Vitro Cellular & Developmental Biology - Plant - Plants have long played a major role in human health as a source of herbal remedies. Recently, transgenic plants have become convenient...     

A mathematical model of maternal vascular growth and remodeling and changes in maternal hemodynamics in uncomplicated pregnancy

The maternal vasculature undergoes tremendous growth and remodeling (G&R) that enables a?>?15-fold increase in blood flow through the uterine vasculature from conception to term. Hemodynamic metrics (e.g., uterine artery pulsatility index, UA-PI) are useful for the prognosis of pregnancy complications; however, improved characterization of the maternal hemodynamics is necessary to improve prognosis. The goal of this paper is to develop a mathematical framework to characterize maternal vascular G&R and hemodynamics in uncomplicated human pregnancies. A validated 1D model of the human vascular tree from the literature was adapted and inlet blood flow waveforms at the ascending aorta at 4 week increments from 0 to 40 weeks of gestation were prescribed. Peripheral resistances of each terminal vessel were adjusted to achieve target flow rates and mean arterial pressure at each gestational age. Vessel growth was governed by wall shear stress (and axial lengthening in uterine vessels), and changes in vessel distensibility were related to vessel growth. Uterine artery velocity waveforms generated from this model closely resembled ultrasound results from the literature. The literature UA-PI values changed significantly across gestation, increasing in the first month of gestation, then dramatically decreasing from 4 to 20 weeks. Our results captured well the time-course of vessel geometry, material properties, and UA-PI. This 1D fluid-G&R model captured the salient hemodynamic features across a broad range of clinical reports and across gestation for uncomplicated human pregnancy. While results capture available data well, this study highlights significant gaps in available data required to better understand vascular remodeling in pregnancy.

     

Introduced Pseudomonas fluorescens VUPf5 as an important biocontrol agent for controlling Gaeumannomyces graminis var. tritici the causal agent of take-all disease in wheat

About 900 bacterial strains obtained from plants rhizosphere from different areas of Iran and biocontrol ability were widely survey in vitro and greenhouse conditions against Gaeumannomyces graminis var. tritici the causal agent of take-all disease. Finally the best strain (VUPf5 strain) in the additional tests biocontrol ability in vitro and greenhouse conditions was selected for next studies. VUPf5 suppressed of take-all disease 85%. Based on biochemical and morphological tests, this isolate is belonging to the species Pseudomonas fluorescens. This isolate significantly produced the secondary metabolites such as siderophores, hydrogen cyanide, protease, phenazine and volatile metabolites.