Effect of multi-walled carbon nanotubes on mechanical and rheological properties of poly(trimethylene terephthalate)

This paper investigates rheological and mechanical properties of poly(trimethylene terephthalate) (PTT) in presence of multi-walled carbon nanotubes (MWCNTs). Morphological characterization by scanning electron microscope and transmission electron microscope showed uniform distribution of MWCNTs in the PTT matrix. Incorporation of MWCNTs into PTT matrix resulted in higher complex viscosity (η), storage (G′) and loss modulus (G″) than those of neat PTT, especially in low-frequency region. The dramatic increase in melt viscosity of PTT observed upon incorporation of MWCNTs in the range of 0.25–1 wt% could be due to the formation of interconnected network of MWCNTs in the polymer matrix, and thus, this can be regarded as rheological percolation threshold concentration. Cole–Cole plot showed change in slope and also shift in G′ versus G″ plot, which suggested change in microstructure upon MWCNT addition. The reinforcing effect of MWCNTs was also confirmed by dynamic mechanical analysis, where, by adding CNTs, a noticeable increase in storage modulus of PTT was observed. However, addition of MWCNTs showed no significant effect on the tensile properties of PTT due to poor interfacial interaction between CNTs and polymer matrix.     

Toward p-type conduction in Cs-doped ZnO: an eco-friendly synthesis method

An alcohol-free, eco-friendly technique was adapted for the synthesis of undoped ZnO and Cs-(cesium) doped ZnO nanoparticles (NPs). The effect of annealing and dopant concentration on its structural and optical properties was investigated. X-ray diffraction results confirmed the formation of polycrystalline hexagonal wurtzite structure and enhanced crystallinity was observed for 1 mol%: Cs-doped ZnO NPs. Scanning electron microscopy results revealed triangular-shaped NPs and increase in the crystallite size is noticed with increase in dopant concentration. UV–visible results showed shift in the band edge toward higher wave length side with increasing Cs concentration. Reduction in bandgap was observed for Cs-doped ZnO NPs, due to quantum confinement effect. Transmittance value increased to 86 % with the inclusion of Cs in ZnO lattice. Room temperature photoluminescence analysis of Cs-doped ZnO NPs reveals bandedge emission along with 450 nm emission due to Zn vacancy and Zn interstitial defects. Electrical measurements confirmed the realization of p-type conductivity in Cs-doped ZnO NPs with a carrier concentration of 1.3 × 10¹⁸/cm³.     

Testis-Specific Isoform of Na+-K+ ATPase and Regulation of Bull Fertility

An advanced understanding of sperm function is relevant for evidence-based male fertility prediction and addressing male infertility. A standard breeding soundness evaluation (BSE) merely identifies gross abnormalities in bulls, whereas selection based on single nucleotide polymorphisms and genomic estimated breeding values overlooks sub-microscopic differences in sperm. Molecular tools are important for validating genomic selection and advancing knowledge on the regulation of male fertility at an interdisciplinary level. Therefore, research in this field is now focused on developing a combination of in vitro sperm function tests and identifying biomarkers such as sperm proteins with critical roles in fertility. The Na⁺-K⁺ ATPase is a ubiquitous transmembrane protein and its α4 isoform (ATP1A4) is exclusively expressed in germ cells and sperm. Furthermore, ATP1A4 is essential for male fertility, as it interacts with signaling molecules in both raft and non-raft fractions of the sperm plasma membrane to regulate capacitation-associated signaling, hyperactivation, sperm-oocyte interactions, and activation. Interestingly, ATP1A4 activity and expression increase during capacitation, challenging the widely accepted dogma of sperm translational quiescence. This review discusses the literature on the role of ATP1A4 during capacitation and fertilization events and its prospective use in improving male fertility prediction.     

Electrochemical characterization of oxide formed on chromium containing mild steel alloys in LiOH medium

Flow accelerated corrosion leads to wall thinning of outlet-feeder pipes in the primary heat transport system of pressurized heavy water reactors and can even necessitate enmasse feeder replacement. Replacement of carbon steel 106-grade-B (CS) with chromium containing carbon steel reduces the risk of this failure. This paper discusses the role of small additions of chromium in modifying the properties of the oxide film. CS and chromium containing mild steels viz., A333, 2.25Cr–1Mo and modified 9Cr–1Mo alloy were exposed to primary heat transport (PHT) system chemistry conditions. The oxide films formed were characterized by electrochemical and surface characterization techniques. Mott–Schottky analysis showed donor type of defects. The densities of defects in the oxides of chromium containing alloys were 3–15 times less than that in CS. In presence of ∼200 ppb of dissolved oxygen, the oxides formed were hematite with two orders of magnitude smaller concentration of defects as compared to that formed under reducing conditions. These results suggest that the presence of chromium lowers the defect density of the oxide film and thus ensures a reduced corrosion rate.     

1-[2-(1-Cyclobutylpiperidin-4-yloxy)-6,7-dihydro-4H-thiazolo[5,4-c]pyridin-5-yl]propan-1-one: a Histamine H3 Receptor Inverse Agonist with Efficacy in Animal Models of Cognition

A series of chemical optimizations, which was guided by in vitro affinity at histamine H₃ receptor (H₃R), modulation of lipophilicity, ADME properties and preclinical efficacy resulted in the identification of 1-[2-(1-cyclobutylpiperidin-4-yloxy)-6,7-dihydro-4H-thiazolo[5,4-c]pyridin-5-yl]propan-1-one ( 45 e ) as a potent and selective (K_i=4.0 nM) H₃R inverse agonist. Dipsogenia induced by (R)-α-methylhistamine was dose dependently antagonized by 45 e , confirming its functional antagonism at H₃R. It is devoid of hERG and phospholipidosis issues. Compound 45 e has adequate oral exposures and favorable half-life in both rats and dogs. It has demonstrated high receptor occupancy (ED₈₀=0.22 mg/kg) and robust efficacy in object recognition task and, dose dependently increased acetylcholine levels in brain. The sub-therapeutic doses of 45 e in combination with donepezil significantly increased acetylcholine levels. The potent affinity, selectivity, in vivo efficacy and drug like properties together with safety, warrant for further development of this molecule for potential treatment of cognitive disorders associated with Alzheimer's disease.     

Structural Characterization and Protective Properties of Spray-Deposited Titania Coating Obtained from Oxime-Modified Titanium(IV) Precursor

Protection of Metals and Physical Chemistry of Surfaces - Spray pyrolytic deposition (SPD) of titania coatings on steel substrates have been carried out using acetoxime-modified titanium(IV)...