Regulation and Role of Neuron-Derived Hemoglobin in the Mouse Hippocampus

Hemoglobin (Hb) is the oxygen transport protein in erythrocytes. In blood, Hb is a tetramer consisting of two Hb-alpha (Hb-α) chains and two Hb-beta (Hb-β) chains. A number of studies have also shown that Hb-α is also expressed in neurons in both the rodent and human brain. In the current study, we examined for age-related regulation of neuronal Hb-α and hypoxia in the hippocampus and cerebral cortex of intact male and female mice. In addition, to confirm the role and functions of neuronal Hb-α, we also utilized lentivirus CRISPR interference-based Hb-α knockdown (Hb-α CRISPRi KD) in the non-ischemic and ischemic mouse hippocampus and examined the effect on neuronal oxygenation, as well as induction of hypoxia-inducible factor-1α (HIF-1α) and its downstream pro-apoptotic factors, PUMA and NOXA, and on neuronal survival and neurodegeneration. The results of the study revealed an age-related decrease in neuronal Hb-α levels and correlated increase in hypoxia in the hippocampus and cortex of intact male and female mice. Sex differences were observed with males having higher neuronal Hb-α levels than females in all brain regions at all ages. In vivo Hb-α CRISPRi KD in the mouse hippocampus resulted in increased hypoxia and elevated levels of HIF-1α, PUMA and NOXA in the non-ischemic and ischemic mouse hippocampus, effects that were correlated with a significant decrease in neuronal survival and increased neurodegeneration. As a whole, these findings indicate that neuronal Hb-α decreases with age in mice and has an important role in regulating neuronal oxygenation and neuroprotection.     

Recycled milk pouch and virgin LDPE‐LLDPE‐based jute fiber composites

The present investigation deals with the thermo‐mechanical recycling of post consumer milk pouches (LDPE‐LLDPE blend) and its use as jute fiber composite materials for engineering applications. The mechanical, thermal, morphological, and dynamic‐mechanical properties of recycled milk pouch‐based jute fiber composites with different fiber contents were evaluated and compared with those of the virgin LDPE‐LLDPE/jute fiber composites. Effect of artificial weathering on mechanical properties of different formulated composites was determined. The recycled polymer‐based jute fiber composites showed inferior mechanical properties as well as poor thermal stability compared to those observed for virgin polymer/jute fiber composites. However, the jute‐composites made with (50:50) recycled milk pouch‐virgin LDPE‐LLDPE blend as polymer matrix indicated significantly superior properties in comparison to the recycled milk pouch/jute composites. Overall mechanical performances of the recycled and virgin polymeric composites were correlated by scanning electron microscopy (SEM). The dynamic mechanical analysis showed that storage modulus values were lower for recycled LDPE‐LLDPE/jute composites compared to virgin LDPE‐LLDPE/jute composites throughout the entire temperature range, but an increase in the storage modulus was observed for recycled‐virgin LDPE‐LLDPE/jute composites. POLYM. COMPOS. 28:78–88, 2007. © 2007 Society of Plastics Engineers     

Excellent electromagnetic interference shielding and mechanical properties accomplished in a manganese dioxide decorated graphene/polymer composite

In this work, we have incorporated pristine graphene and graphene sheets decorated with α and δ forms of manganese dioxide in a hydrogenated nitrile butadiene rubber matrix to obtain high-performance composites. The dual mixing technique was adopted to fabricate the composites having enhanced tensile, dielectric, and electromagnetic interference (EMI) shielding properties. The pristine graphene was introduced at various loadings, however, the α and δ manganese dioxide doped graphene was integrated at a single 8 phr concentration onto the rubber matrix. At an optimized concentration of 8 phr graphene in the matrix, a 101% increase in the tensile strength was observed compared to the unfilled rubber. An excellent improvement in the dielectric properties and a high EMI shielding value of 24.5 dB was observed for the15 phr loaded composite having a thickness of 2 mm. The composites should principally find applications as a robust and lightweight EMI shielding material.     

Properties of spray-deposited cobalt oxide selective coatings on aluminium and galvanised iron substrates

Highly stable selective coatings of cobalt oxide have been prepared on commercial aluminium and galvanised iron substrates by the method of spray pyrolysis. The optothermal, structural and optical properties of these films have been investigated to determine the optimum growth parameters. Best selectivity values are obtained for films with thicknesses 0·30 μm on aluminium and 0·32 μm on galvanised iron. The optimised films on aluminium give = 0·88 and _100°C = 0·15 whereas those on galvanised iron give = 0·88 and _100°C = 0·13. The films are extremely adherent and are stable up to 500°C in the case of aluminium and 350°C in the case of galvanised iron substrates.     

Influence of interaction promoter on the properties of thermoplastic elastomeric blends of natural rubber and polyethylene

The influence of a third component as interaction promoter on the properties of natural rubber-polyethylene thermoplastic blends, both uncured and cured, has been studied. The third component chosen has some structural similarity with polyethylene and is amorphous in nature. Ethylene propylene diene (EPDM) rubber, chlorinated polyethylene and chlorosulphonated polyethylene have been used as the third component. All the third components have better adhesion with the plastic phase and the rubber phase. The adhesive strength is highest with EPDM. The properties are improved by using the above third components both for cured and uncured blends. In comparing the properties, the strength of the composite is divided by the modulus of the composite to take care of the hard-phase contribution. The size of the dispersed domain is reduced by using the third component and is approximately 1.2 m. All the properties could be explained in terms of the strengths of the individual phases, the morphology and the adhesion between components.     

Investigations of the effect of non-uniform insert pitch on vibration during face milling

In the present work optimal tooth spacing vs spectral redistribution criteria for face milling has been used as one of the methods for vibration control. A special milling cutter with non-uniform pitch has been designed and fabricated and its effect on machine tool vibration is studied. The frequency response spectrum of the machine tool is found out analytically using Finite Element Programme. The spacing between the teeth of milling cutters is found out by minimizing the total power of the relative cutter-workpiece vibration. The newly designed cutter is fabricated and tested experimentally to determine its effectiveness when compared with a standard cutter with evenly spaced inserts.