Impact of open dumping of municipal solid waste on soil properties in mountainous region

This paper presents the effect of open dumping of municipal solid waste(MSW) on soil characteristics in the mountainous region of Himachal Pradesh, India. The solid waste of dumpsite contains various complex characteristics with organic fractions of the highest proportions. As leachate percolates into the soil, it migrates contaminants into the soil and affects soil stability and strength. The study includes the geotechnical investigation of dump soil characteristics and its comparison with the natural soil samples taken from outside the proximity of dumpsites. The geochemical analysis of dumpsite soil samples was also carried out by scanning electron microscopy(SEM) and energy dispersive X-ray spectroscopy(EDS).Visual inspection revealed that the MSW consists of high fraction of organics, followed by paper. The soil samples were collected from five trial pits in the dumpsites at depths of 0.5 m, 1 m and 1.5 m. Then the collected soil samples were subjected to specific gravity test, grain size analysis, Atterberg’s limit test,compaction test, direct shear test, California bearing ratio(CBR) test and permeability analysis. The study indicated that the dumpsite soils from four study regions show decreasing trends in the values of maximum dry density(MDD), specific gravity, cohesion and CBR, and increasing permeability as compared to the natural soil. The results show that the geotechnical properties of the soils at all four study locations have been severely hampered due to contamination induced by open dumping of waste.

Tailoring of structural,optical and electrical properties of anatase TiO_(2)via doping of cobalt and nitrogen ions

Pure(pristine)anatase and mono–doped and co–doped derivatives of TiO_(2)having nitrogen(N)and cobalt(Co)as dopants with respective fixed doping concentrations of 0.7 mol.%and 1.0 mol.%were synthesized using auto–combustion sol–gel technique.The doping effects at corresponding non–metal and transition metal sites of TiO_(2)on the basis of the structural,optical and electrical properties have been investigated.X–ray diffraction(XRD)measurement confirms the formation of pure anatase phase of TiO_(2)for all samples having I41/amd space group of tetragonal structure which has been also verified by the Raman spectroscopy measurement.Various crystallographic parameters have been calculated by performing Rietveld refinement of XRD data including average crystallite size that has been observed in the range of10–15 nm.Pure anatase phase indicates the incorporation of Co^(2+)into TiO_(2)lattice which assists the substitution of N in place of oxygen in co–doped TiO_(2).The band gap tuning towards the visible region from3.2 to 2.1 e V has been achieved with mono–doping and co–doping of the N and Co in TiO_(2)lattice.This can be described in terms of the formation of localized levels of N–2p and Co–3d states in mono–doping and an isolated intermediate band formation in co–doping case.Electrical properties have been investigated in details and explained as the synergetic effects of structural and inherent ionic characters of various dopants.The observed band gaps of all doped samples lie within the visible region which makes them pertinent as the solar energy harnessing materials for photocatalytic and photovoltaic applications.

Loss of the BRCA1-PALB2 interaction accelerates p53-associated tumor development in mice

The BRCA1-PALB2-BRCA2 axis,or the BRCA pathway,plays key roles in genome stability maintenance and suppression of breast and several other cancers.Due to frequent p53 mutations in human BRCA1 breast cancers and mouse mammary tumors from Brcal,Brca2 and Palb2 conditional knockout models,it is often thought that p53 inactivation accelerates BRCA1/2 and PALB2-associated tumorigenesis.Here,we studied tumor development in mice with a mutation in Palb2 that disengages the PALB2-BRCA1 interaction in different Trp53 backgrounds.Rather than mammary tumors,Palb2 and Trp53 compound mutant mice developed,with greatly reduced latencies,lymphomas and sarcomas that are typically associated with germline Trp53 inactivation.Whole exome sequencing failed to identify any significant differences in genomic features between the same tumor types of Trp53 single mutant and Palb2;Trp53 compound mutant mice.These results suggest that loss of the BRCA pathway accelerates p53-associated tumor development,possibly without altering the fundamental tumorigenic processes.