The effects of heat stress exposure on free amino acid concentrations within the plasma and the brain of heat-exposed chicks: A systematic review and meta-analysis.

This study was conducted in order to investigate the effects of heat stress exposure on the concentrations of amino acids within the plasma and the brain of chicks. Methodology: Five electronic databases including; PubMed, Scopus, Web of Science, Embase and ProQuest were reviewed to find relative literature published until the March 8, 2019. A total of eight relative studies and 194 chicks were analyzed. The Random Effects model and the Fixed Effects model were performed. Using the Random Effects model for amino acids, a Standardized mean difference (SMD) of 2.05 and 1.46 was obtained for alanine and threonine concentrations respectively. This indicates a significant increase in the concentration of these amino acids within the plasma. An SMD of -2.68 and -2.46 was obtained for cysteine and proline concentrations respectively, this indicates a significant decrease in the concentration of these amino acids within the plasma. The pooled estimates regarding the effect of heat stress exposure on plasma amino acid concentrations for proline were -0.013. The SMDs obtained for amino acid concentrations within the brain (diencephalon) including leucine, methionine, valine and isoleucine were 1.799, 0.88, 2.11, 1.85, respectively, This indicates a significant increase in the concentration of these amino acids within the brain (P < 0.05). Comparing the SMD obtained for long-term heat exposure (two weeks) with the SMD obtained for short-term heat exposure shows that plasma amino acid concentrations including aspartic acid, glutamic acid, leucine, lysine, methionine, valine, isoleucine, tyrosine, glycine, proline, phenylalanine and threonine had all decreased. The relationship between heat exposure and changes in the concentration of some amino acids in the plasma is an important scientific finding.

Extraction of Hydroxyapatite Nanostructures from Marine Wastes for the Fabrication of Biopolymer-Based Porous Scaffolds.

Three-dimensional porous nanocomposites consisting of gelatin-carboxymethylcellulose (CMC) cross-linked by carboxylic acids biopolymers and monophasic hydroxyapatite (HA) nanostructures were fabricated by lyophilization, for soft-bone-tissue engineering. The bioactive ceramic nanostructures were prepared by a novel wet-chemical and low-temperature procedure from marine wastes containing calcium carbonates. The effect of surface-active molecules, including sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium bromide (CTAB), on the morphology of HA nanostructures is shown. It is demonstrated that highly bioactive and monophasic HA nanorods with an aspect ratio > 10 can be synthesized in the presence of SDS. In vitro studies on the bioactive biopolymer composite scaffolds with varying pore sizes, from 100 to 300 µm, determine the capacity of the developed procedure to convert marine wastes to profitable composites for tissue engineering.

Carbon-Pt nanoparticles modified TiO2 nanotubes for simultaneous detection of dopamine and uric acid.

The present work describes sensing application of modified TiO2 nanotubes having carbon-Pt nanoparticles for simultaneous detection of dopamine and uric acid. The TiO2 nanotubes electrode was prepared using anodizing method, followed by electrodeposition of Pt nanoparticles onto the tubes. Carbon was deposited by decomposition of polyethylene glycol in a tube furnace to improve the conductivity. The C-Pt-TiO2 nanotubes modified electrode was characterized by cyclic voltammetry and differential pulse voltammetry methods. The modified electrode displayed high sensitivity towards the oxidation of dopamine and uric acid in a phosphate buffer solution (pH 7.00). The electro-oxidation currents of dopamine and uric acid were linearly related to the concentration over a wide range of 3.5 x 10(-8) M to 1 x 10(-5) M and 1 x 10(-7) M to 3 x 10(-5) M respectively. The limit of detection was determined as 2 x 10(-10) M for dopamine at signal-to-noise ratio of 3. The interference of uric acid was also investigated. Electro-oxidation currents of dopamine in the presence of fix amount of uric acid represented a linear behaviour towards successive addition of dopamine in range of 1 x 10(-7) M to 1 x 10(-5) M. Furthermore, in a solution containing dopamine, uric acid and ascorbic acid the overlapped oxidation peaks of dopamine and ascorbic acid could be easily separated by using C-Pt-TiO2 nanotubes modified electrode.

Sensitive determination of dopamine in the presence of uric acid and ascorbic acid using TiO2 nanotubes modified with Pd, Pt and Au nanoparticles.

A simple modified TiO(2) nanotubes electrode was fabricated by electrodeposition of Pd, Pt and Au nanoparticles. The TiO(2) nanotubes electrode was prepared using the anodizing method, followed by modifying Pd nanoparticles onto the tubes surface, offering a uniform conductive surface for electrodeposition of Pt and Au. The performance of the modified electrode was characterized by cyclic voltammetry and differential pulse voltammetry methods. The Au/Pt/Pd/TiO(2) NTs modified electrode represented a high sensitivity towards individual detection of dopamine as well as simultaneous detection of dopamine and uric acid using 0.1 M phosphate buffer solution (pH 7.00) as the base solution. In both case, electro-oxidation peak currents of dopamine were linearly related to accumulated concentration over a wide concentration range of 5.0 × 10(-8) to 3.0 × 10(-5) M. However in the same range of dopamine concentration, the sensitivity had a significant loss at Pt/Pd/TiO(2) NTs electrode, suggesting the necessity for Au nanoparticles in modified electrode. The limit of the detection was determined as 3 × 10(-8) M for dopamine at signal-to-noise ratio equal to 3. Furthermore, the Au/Pt/Pd/TiO(2) NTs modified electrode was able to distinguish the oxidation response of dopamine, uric acid and ascorbic acid in mixture solution of different acidity. It was shown that the modified electrode possessed a very good reproducibility and long-term stability. The method was also successfully applied for determination of DA in human urine samples with satisfactory results.