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Spectacularly preserved yet least studied middle to late Eocene Kopili Formation in parts of East Jaintia Hills district, Meghalaya has been documented to understand the provenance, tectonic setting and palaeoweathering employing petrological and geochemical attributes. The Kopili Formation is characterized by alternations of fossiliferous marl-splintery grey to black shale-siltstone and fine to medium grained ferruginous sandstone with occasional coal streaks. Petrographically, Kopili sandstone has been grouped into two categories i.e. subarkose and sublitharenite. Geochemically, Kopili sandstone possesses high SiO2 and relatively low Al2O3 and Fe2O3 confirming to the modal composition Q72.70 F6.57 RF7.01 CT3.12 Mx2.28 M2.07 HM1.82. These are quartz-rich (SiO2 75.96%) clean sandstone depicting strong negative correlation of SiO2 with rest of the major oxide except for CaO which is relatively weak. High SiO2 is in conformity with quartz enrichment (73.50%), does indicate a passive (atlantic type) continental margin set up for the deposition of Kopili Formation. Neo-development of quartz and feldspar in parts reflect high degree of diagenesis. Chemical indices like CIA, CIW, PIA and ICV reveal intense weathering under semi-arid to semi-humid climatic conditions. Besides minor contributions from continent interior, sediments were largely derived from recycled orogen involving rhyolitic / granitic sources containing plagioclase feldspars in the range of An0-An70 as evident from geochemical attributes. [ABSTRACT FROM AUTHOR]

An attempt has been made to estimate the site amplification factors of different geomorphological units in Shillong city, northeastern India, based on the distribution of peak ground acceleration (PGA) due to maximum credible earthquakes that originated in nearby major faults. Empirical relations are used to determine the amount of shaking at base rock as a function of the magnitude of the earthquake (Mw), source depth (km), fault dimension (intraplate/interplate), velocity structure of medium and the distance from the source (km). The computed PGA values are convolved with the average shear wave velocity (Vs30) values at various geomorphological units of Shillong to ascertain the degree of amplification while travelling from base rock to the surface. The amplification for the highly dissected land in the city is found to be the maximum within a range of 2.77–2.92, while the high plateau segment is characterized by least values (2.01–2.16). Simultaneously, the effective ground motion mapped on the surface indicates the maximum value of 0.6–0.94 g for a probable earthquake of Mw 8.1 due to Dauki fault. Similarly, Dhubri and Kopili faults might produce a ground motion of 0.05–0.08 and 0.22–0.33 g for a maximum credible earthquake of Mw~7.0, respectively. [ABSTRACT FROM AUTHOR]

The present paper attempts to investigate the possible syllable structure of Pnar language, which is an Austro Asiatic language belonging to the Mon Khmer group. Pnar is spoken in Jayantia Hills district of Meghalaya which has been bifurcated into East Jayantia Hills District and West Jayantia Hills District in 2012. The study is based on Clement & Kesyer (1983) proposed idea of CV tier on syllable structure. The paper elaborates the major syllable structure of Pnar language and various classifications of Pnar words on the basis of CV structure. Every language has their own syllable structure which is depend on the speech sounds unit of particular language. The methodologies that adopted for the present study are interview method and the observation method for which the complete observation took place on data collected from the informants of Jawai, Shillong, Meghalaya. The study reveals that Pnar language has all four basic syllable structures. [ABSTRACT FROM AUTHOR]

Background: Highest incidence of oral squamous cell carcinoma (OSCC) has been reported in north-eastern India and causal association between cancer and raw areca-nut (RAN) consumption are well evident. Earlier studies revealed that monitoring the occurrence of precocious anaphase and expression of securin in blood lymphocytes can be a good biomarkers for cancer risk in RAN+lime chewers. Glutathione S -transferases (GSTs) are considered an important cellular detoxification system that provide protection against the effects of toxins and determine individual's cancer susceptibility. Aim: Although GST gene family has been extensively studied, its role as susceptibility factor in oral cancer risk in the RAN chewing population in Meghalaya state, India has not been explored. The association of polymorphisms in GSTP1 (Ile105Val) gene with OSCC risk in Meghalaya, India, was evaluated. Earlier both AA reference and the GG/AG mutant genotype of GSTP1 gene showed an association with different types of cancers. Methods: Genetic polymorphism was evaluated by genotyping 129 cases and 156 controls using PCR-RFLP method and validated by Sanger sequencing in a hospital-based case-control study. GSTP1's interaction status with c-Jun Kinase (JNK) was evaluated through protein-protein docking analysis and this was also validated experimentally by immunohistochemistry and qRT-PCR. Results: Individuals with AA allele of GSTP1 showed significant association with the risk of OSCC compared with individuals with AG/GG mutant genotypes in habit-matched "RAN-only" and "RAN+Tobacco" group. The binding geometry between JNK and GSTP1 was disrupted in mutant combinations. It was demonstrated that AA homozygous genotype of oral epithelial cells showed reduced c-Jun-phosphorylation and proapoptotic genes expression than AG/GG genotypes. In silico docking revealed that homodimeric GSTP1 with AA genotype showed weak catalytic activity in detoxification of RAN and tobacco toxins compared with the AG/GG mutant proteins. Interestingly, the quantitation of 8-Oxo-2´-deoxyguanosine in DNA digests by ELISA-kit showed no differences in these genotypes, however the frequency of sister-chromatid exchanges was significantly higher in individuals with GSTP1 AA genotype than GG genotype. Conclusion: Thus in this population, specific traditional habit along with GSTP1 AA genotype play a significant role in predisposition to oral cancer risk by showing higher DNA-lesions, might be caused by some specific RAN/tobacco metabolites, and lower c-Jun phosphorylation which may inhibit apoptosis. [ABSTRACT FROM AUTHOR]