Total and acylated ghrelin levels in children and adolescents with idiopathic short stature and poor appetite

Context. Ghrelin is a hormone secreted primarily from stomach that can affect growth by its somatotropic and orexigenic activities. Objective. The aim of this study was to investigate the relationship of ghrelin and growth in children and adolescents with idiopathic short stature. Subjects and Methods. After thorough clinical examination, 56 subjects including 31 with normal weight and height and 25 with short stature were evaluated for fasting total (TG) and acylated (active) ghrelin (AG) levels. All the parameters of growth including growth hormone and IGF-1 levels, bone age and body mass index were also investigated. Appetite was also assessed and all the studied subjects were also divided into two groups, poor or good appetite. Results. TG and AG levels were not significantly different in the two groups. There was not any significant correlation between ghrelin and parameters of growth. On the other hand, TG concentration was significantly higher in subjects with poor appetite, but AG was not significantly different. Conclusions. The results of this study show that ghrelin is not significantly altered in idiopathic short stature. Although TG is increased in children with poor appetite its acylation is not increased concomitantly. © 2015, Editura Academiei Romane. All rights reserved

Synthesis, modification and optimization of titanate nanotubes-polyamide thin film nanocomposite (TFN) membrane for forward osmosis (FO) application

In the present study, the self-synthesized thin film nanocomposite (TFN) membrane incorporated with hydrophilic functionalized titanate nanotubes (TNTs) has been fabricated and tested for forward osmosis (FO) desalination. The ATR-FTIR results showed that NH2-TNTS were successfully modified by AATPS and while TEM and XRD revealed the tubular morphology and crystal structure of NH2-TNTs nanotubes, respectively. The presence of the chemical bondings between NH2-TNTs and polyamide (PA) selective top layer of TFN is corroborated with the FTIR results. The existence of NH2-TNTs in PA top layer was further confirmed by XPS analysis on the control and TFN membranes. The effect of NH2-TNTs on the PA layer was investigated and discussed in terms of surface morphology and separation performance. The morphology of the PA layer was investigated through FESEM and AFM micrographs and the outgrowth of the "leaf-like" structure was observed following the increase in NH2-TNTs content. Compared to the thin film composite (TFC) control membrane, the TFN membrane embedded with 0.05wt% NH2-TNTs (designated as TFN0.05) exhibited two times improvement in water flux without sacrificing salt rejection

Influence of mesoporous phosphotungstic acid on the physicochemical properties and performance of sulfonated poly ether ether ketone in proton exchange membrane fuel cell

This study demonstrates the successful development of hybrid mesoporous siliceous phosphotungstic acid (mPTA-Si) and sulfonated poly ether ether ketone (SPEEK) as a proton exchange membrane with a high performance in hydrogen proton exchange membrane fuel cells (PEMFC). SPEEK acts as a polymeric membrane matrix and mPTA-Si acts as the mechanical reinforcer and proton conducting enhancer. Interestingly, incorporating mPTA-Si did not affect the morphological aspect of SPEEK as dense membrane upon loading the amount of mPTA-Si up to 2.5 wt%. The water uptake reduced to 14% from 21.5% when mPTA-Si content increases from 0.5 to 2.5 wt% respectively. Meanwhile, the proton conductivity increased to 0.01 Scm−1 with 1.0 wt% mPTA-Si and maximum power density of 180.87 mWcm−2 which is 200% improvement as compared to pristine SPEEK membrane. The systematic study of hybrid SP-mPTA-Si membrane proved a substantial enhancement in the performance together with further improvement on physicochemical properties of parent SPEEK membrane desirable for the PEMFC application

Power generation and wastewater treatment using a novel SPEEK nanocomposite membrane in a dual chamber microbial fuel cell

In this paper, the performance of two common and two self-fabricated proton exchange membranes were compared. Nafion 112 and Nafion 117, which are two of the most common proton exchange membranes that can be used in all fuel cell systems, were compared to SPEEK and SP/CC/TAP. The results showed that at lower COD such as 2000 mg/l, Nafion 117 has the highest performance in terms of power production and COD removal, while once the COD of wastewater goes up to 5000 mg/l, SP/CC/TAP has approximately the same performance as Nafion 117. The membranes were characterized by FESEM, while the degree of sulfonation was measured by NMR. The oxidation activity of microorganisms was measure by cyclic voltammetry (CV). Also, the attachment of bacteria onto the anode electrode was observed by SEM, which showed that different bacteria from the media with a mixed culture inoculum had attached to the anode electrode

Power generation and wastewater treatment using a novel SPEEK nanocomposite membrane in a dual chamber microbial fuel cell

In this paper, the performance of two common and two self-fabricated proton exchange membranes were compared. Nafion 112 and Nafion 117, which are two of the most common proton exchange membranes that can be used in all fuel cell systems, were compared to SPEEK and SP/CC/TAP. The results showed that at lower COD such as 2000 mg/l, Nafion 117 has the highest performance in terms of power production and COD removal, while once the COD of wastewater goes up to 5000 mg/l, SP/CC/TAP has approximately the same performance as Nafion 117. The membranes were characterized by FESEM, while the degree of sulfonation was measured by NMR. The oxidation activity of microorganisms was measure by cyclic voltammetry (CV). Also, the attachment of bacteria onto the anode electrode was observed by SEM, which showed that different bacteria from the media with a mixed culture inoculum had attached to the anode electrode

Development of dense void-free electrospun SPEEK-Cloisite15A membrane for direct methanol fuel cell application: optimization using response surface methodology

Response surface methodology (RSM) was utilized to design the experiments at the settings of solution concentration, voltage and the collector distance. It also imparted the evaluation of the significance of each parameter on the resultant physico chemicals (proton conductivity, methanol permeability and water uptake). The investigations were carried out in the two-variable process domains of several collector distances as applied voltage and the solution concentration were varied at a fixed polymer molecular weight. The result showed that all three factors were found statistically significant in the production of void free electrospun SPEEK/Cloisite membrane. All responses were correlated to these variables by using a second order polynomial function. The optimum condition for void free electrospun SPEEK/cloisite was at 0.17 wt% concentration with applied voltage of 22.15 kV and 18.83 cm distance from needle tip to screen collector