Elucidation of physico-chemical characteristics and mycoflora of bovine milk available in selected area of Karachi, Pakistan.

ISO 14000 has opened the field for enhancing the awareness towards healthy environment and gives the ideology of regular assessment of threshold values not only of nutrients but contaminants as well. Under this statement microbiological studies in terms of mycoflora followed by physical characteristics and level of some essential elements Mg, Fe, Cu and Zn, and deleterious metal Cd were analyzed in fresh milk samples (FMS) and tetra pack milk or UHT processed milk samples (PMS) available in Gulshan-e-Iqbal Town, Karachi for the residents. Samples were collected in the morning time during winter season. Physical parameters like pH, conductivity, density, viscosity, surface tension and refractive index were observed very soon after sample collection. Percentage of ash and total dissolved solids (TDS) were also measured. For fungal flora studies PDA (Potato Dextrose Agar) and Sabourouds Agar were used for the fungal growth. The concentrations of metals considered were estimated after wet digestion of samples using atomic absorption spectroscopy. The ranges of average concentration of Mg, Fe, Cu and Zn were found to be 77.120 – 141.915mg/l, 0.580 – 7.320mg/l, 0.004 – 0.070mg/l and 2.574 – 4.872mg/l. The level of Cd was estimated in the samples between 0.0050 – 0.053mg/l, but was not observed in most of the samples. Among the fungi, the highest diversity was that of Aspergillus spp. that produces aflatoxins. ©JASEMKey words: physical characteristics, essential elements, toxic elements, fungal specie

Enhanced hard magnetic properties in partially-doped Mn3-xGdxGa (x <= 0.03)

The effect of partial (1-3%) rare-earth Gadolinium doping in D0(22 )Mn(3)Ga hard magnet has been investigated in this work. The Mn 3 Ga undergoes magnetic transition at T-c similar to 745 K, which decreases down to T-c similar to 715 K upon 1% Gd-doping with introduction of mixed Mn valence states, as revealed from XPS study. The hard magnetic behavior of Mn3Ga has been observed in a wide temperature range (up to T-c ). More importantly, the partial Gd-doping significantly enhances the room temperature hard magnetic properties i.e. squareness ratio (m(r)/m(s)), coercivity (H-c) and energy product (BHmax ) from 0.43, 2.73 kOe and 0.39 MGOe (Mn3Ga) to 0.57, 4.25 kOe and 0.5 MGOe (Mn2.97Gd0.03Ga), respectively. The modified Stoner-Wohlfarth model and low-field minor loop analysis reveal the nucleation hardening mechanism for the magnetization reversal. The study proposes the partial rare-earth doping as a new approach to enhance the hard magnetic properties of rare-earth free hard magnets

Signature of a Griffiths phase in layered canted antiferromagnet Sr2IrO4

The complex magnetic nature of 5d layered iridate Sr2IrO4, owing to Ir0 6 octahedral rotation has triggered great interest in recent years. In this article, we investigated the magnetic excitations in layered canted antiferromagnet Sr2IrO4 via dc magnetization measurements and report the Griffiths phase (GP) signatures above the magnetic ordering temperature T-N. The non-analytic nature of GP leads to unique critical exponent, beta = 0.75(1) extracted from modified Arrott plot, in corroboration with magneto-caloric study. However, the analysis by Bray model in GP regime yields a reliable critical exponent value of beta = 0.18(1), belonging to two-dimensional XYh(4) universality class. The study also suggests a new picture of largely debated insulating nature of Sr2IrO4 in context of GP above T-N

Intrinsic property of phenylalanine to trigger protein aggregation and hemolysis has a direct relevance to phenylketonuria

Abstract Excess accumulation of phenylalanine is the characteristic of untreated Phenylketonuria (PKU), a well-known genetic abnormality, which triggers several neurological, physical and developmental severities. However, the fundamental mechanism behind the origin of such diverse health problems, particularly the issue of how they are related to the build-up of phenylalanine molecules in the body, is largely unknown. Here, we show cross-seeding ability of phenylalanine fibrils that can effectively initiate an aggregation process in proteins under physiological conditions, converting native protein structures to β-sheet assembly. The resultant fibrils were found to cause severe hemolysis, yielding a plethora of deformed erythrocytes that is highly relevant to phenylketonuria. Unique arrangement of zwitterionic phenylalanine molecules in their amyloid-like higher order entities is predicted to promote both hydrophobic and electrostatic interaction, sufficient enough to trap proteins and to preferentially interact with the membrane components of RBCs. Since the prevalence of hemolysis and amyloid related psychoneurological severities are mostly observed in PKU patients, we propose that the inherent property of phenylalanine fibrils to trigger hemolysis and to induce protein aggregation may have direct relevance to the disease mechanism of PKU