Evolution of b-values before large earthquakes of mb ≥6.0 in the Andaman region

We have considered six earthquakes of mb ≥6.0, with focal depths within 45 km, in Andaman region during 2000 to 2012 to examine the spatial variations of b-value at epicentre within a one-year period prior to the occurrence of the earthquakes. We have found a correlation between the low b for the one year time interval and the occurrence of large events. The epicentral b-values of six earthquakes are lower than 1.0 and five out of six earthquakes show very low b-value at the epicentre. Our study may indicate that b-value can be employed as a possible precursor for the forecasting of a major earthquake

A review of crust and upper mantle structure beneath the Indian subcontinent

This review presents an account of the variations in crustal and upper mantle structure beneath the Indian subcontinent and its environs, with emphasis on passive seismic results supplemented by results using controlled seismic sources. Receiver function results from more than 600 seismic stations, and over 10,000 km of deep seismic profiles have been exploited to produce maps of average crustal velocities and thickness across the region. The crustal thickness varies from 29 km at the southern tip of India to 88 km under the Himalayan collision zone, and the patterns of variation show significant deviations from the predictions of global models. The average crustal shear velocity (Vs) is low in the Himalaya–Tibet collision zone compared to Indian shield. Major crustal features are as follows: (a) the Eastern Dharwar Craton has a thinner and simpler crustal structure crust than the Western Dharwar Craton, (b) Himalayan crustal thickness picks clearly follow a trend with elevation, (c) the rift zones of the Godavari graben and Narmada–Son Lineament show deeper depths of crust than their surroundings, and (d) most of the Indian cratonic fragments, Bundelkhand, Bhandara and Singhbhum, show thick crust in comparison to the Eastern Dharwar Craton. Heat flow and crustal thickness estimates do not show any positive correlations for India. Estimates of the thickness of the lithosphere show large inconsistencies among various techniques not only in terms of thickness but also in the nature of the transition to the asthenosphere (gradual or sharp). The lithosphere beneath India shows signs of attrition and preservation in different regions, with a highly heterogeneous nature, and does not appear to have been thinned on broader scale during India's rapid motion north towards Asia. The mantle transition zone beneath India is predominantly normal with some clear variations in the Himalayan region (early arrivals) and Southwest Deccan Volcanic Province and Southern Granulite Terrain (delayed arrivals). No clear patterns on influence on the mantle transition zone discontinuities can be associated with lithospheric thickness. Over 1000 anisotropic splitting parameters from SKS/SKKS phases and 139 using direct S waves are available from various studies. The shear-wave splitting results clearly show the dominance of absolute-plate-motion related strain of a highly anisotropic Indian lithospheric mantle with delay times between the split S phases close to 1 s. There are still many parts of India where there is, at best, limited information on the character of the crust and the mantle beneath. It is to be hoped that further installations of permanent and temporary stations will fill these gaps and improve understanding of the geodynamic environment of the Indian subcontinent.This study has been supported by a grant from the Ministry of Earth Sciences (MoES), IITKGP/CKH

Production of tetanus toxin by using media substantially free from meat and blood

The present study was to redesign the conventional Mueller and Miller medium to produce tetanus toxin from Clostridium tetani. Meat based ingredients (such as Bovine Heart/ Brain/ Liver Infusion) were replaced with vegetable peptone & alternate casein hydrolysate and scaled up from 100mL to 1000mL. Modified Mueller and Miller Medium containing vegetable peptone (substitute of BHI) and alternate casein hydrolysate were used for production and scale -up of tetanus toxin. Detoxification of tetanus toxin was carried out by using formaldehyde to produce tetanus toxoid. Purification of tetanus toxoid was achieved by fractional precipitation. It was found that under optimum conditions, use of meat free media leads to production of tetanus toxin with equal limes flocculation (Lf) titer and high antigenic content at par with conventional meat based media without any post vaccination infections. The yield of toxin was improved during scale-up of the process. The present study provides a method for growth of Clostridium tetani that maximizes tetanus toxin production without any use of animal-derived components

Association of Cutibacterium acnes with human thyroid cancer

IntroductionThe diverse subtypes of thyroid carcinoma have distinct clinical outcomes despite a comparable spectrum of underlying genetic alterations. Beyond genetic alterations, sparse efforts have been made to characterize the microbes associated with thyroid cancer. In this study, we examine the microbial profile of thyroid cancer.MethodsWe sequenced the whole transcriptome of 70 thyroid cancers (40 papillary and 30 anaplastic). Using Infectious Pathogen Detector IPD 2.0, we analysed the relative abundance of 1060 microbes across 70 tumours from patients with thyroid cancer against 118 tumour samples from patients with breast, cervical, colorectal, and tongue cancer.ResultsOur analysis reveals a significant prevalence of Cutibacterium acnes in 58.6% thyroid cancer samples compared to other cancer types (p=0.00038). Immune cell fraction analysis between thyroid cancer samples with high and low Cutibacterium loads identify enrichment of immunosuppressive cells, including Tregs (p=0.015), and other anti-inflammatory cytokines in the tumour microenvironment, suggesting an immune evasion/immunosuppression milieu is associated with the infection. A higher burden of Cutibacterium acnes was also found to be associated with poor survival defining a distinct sub-group of thyroid cancer.ConclusionCutibacterium acnes is associated with immune suppression and poor prognosis in a subpopulation of thyroid cancer. This study may help design novel therapeutic measures involving appropriate antibiotics to manage the disease better

Spatial variation of seismic b-values across the NW Himalaya

The frequency–magnitude distribution is investigated along the entire north-western Himalaya (28°–36°N; 72°–81°E). The analysis includes a complete set of 1819 earthquakes of Mb ≥ 2.9 taken from the International Seismological Catalogue (ISC) bulletin which occurred between 1964 and 2010. The study area has been divided into three blocks (A, B and C) that include the Kashmir, Kangra–Chamba and Garhwal–Kumaun segments, respectively. The b-value of each block has been determined to see the disparity among the different segments. A comprehensive study of the spatial mapping of frequency–magnitude distribution is also made for the whole area. Significant variations in the b-value are detected with b ranging from b ≈ 0.6 to 1.3. The study shows that the accumulated stresses are high at the Kumaun as well as in the Kangra–Chamba region which may indicate the possibility of future large earthquakes at these locations

Evolution of b-values before large earthquakes of mb ≥6.0 in the Andaman region

We have considered six earthquakes of mb ≥6.0, with focal depths within 45 km, in Andaman region during 2000 to 2012 to examine the spatial variations of b-value at epicentre within a one-year period prior to the occurrence of the earthquakes. We have found a correlation between the low b for the one year time interval and the occurrence of large events. The epicentral b-values of six earthquakes are lower than 1.0 and five out of six earthquakes show very low b-value at the epicentre. Our study may indicate that b-value can be employed as a possible precursor for the forecasting of a major earthquake

Seismic noise analysis of broadband stations in the Eastern Ghat Mobile Belt of India using power spectral density

The seismic background noise is studied at newly constructed sites of the Eastern Ghat Mobile Belts (EGMB), in Orissa. Ten broadband stations have been deployed along two profiles. The area has not been previously attempted for any broadband experiment. To assess the performance of the stations, we investigate the characteristics of different types of noises dominated at those sites. The power spectral densities of ambient background noise for each site are calculated and compared with the global noise model. The results suggest that the noise levels at all stations that belong to profile-1 are within the global high and low bounds. Along profile-2, the station PATN stabilizes after some time post-deployment while noise levels at other two stations are within the proposed limits. Results show that profile-1 is predominated by cultural noise, and the microseismic noise levels are observed to be low in both the profiles. Assessment of the temporal and seasonal variation of the noise has also been done, along with the calculation of the power spectral densities in the East and North components of the seismometer for this station. Overall, our observations suggest that installation of the seismometers have been successful in all the sites

Tumor Microenvironment and Its Role in Racial Disparities Observed in Prostate Cancer

Disparities in cancer are common among the racial and ethnical minorities in the United States and are of significant social and clinical concern. Prostate cancer is the most commonly diagnosed non-cutaneous malignancy in American men and exhibits substantial racial disparities with African American men bearing the highest burden in terms of incidence and mortality. A multitude of factors, including socioeconomic, behavioral, and access to healthcare, have been implicated as the underlying causes of such disparities. More recent data also suggest that there are inherent genetic and biological differences in prostate tumors of patients having distinct racial backgrounds. Tumor microenvironment has tremendous impact on the course of cancer progression and clinical outcome and may also contribute to the racial disparities observed in prostate cancer. A better understanding of critical differences in the tumor microenvironment components will provide newer directions to study the biological causes of prostate cancer health disparities and may identify novel therapeutic targets. This review discusses the findings related to the tumor microenvironment differences between the of African American and Caucasian American prostate cancer patients to suggest their potential significance in prostate cancer disparities