Assessment of NORMs (238U, 232Th, 40K) and radiation hazard indices in Beldih apatite mine region of Purulia district, West Bengal, India

The radiation arising from naturally occurring radioactive materials (NORMs) is the foremost contributor to the collective dose received by the global population. The present study aims to measure the natural background radiation level and the associated gamma radiation dose in air in the Beldih apatite mine region of Purulia district, India. This study is primarily focused on the determination of 238U, 232Th and 40K activities in the sub-surface soil of the study area. The measurements were carried out using a High Purity Germanium (HPGe) detector-based gamma-ray spectrometer with a relative efficiency of 80%. To achieve uniformity in exposure estimations, radium equivalent activity has been calculated. Additionally, the internal hazard index, external hazard index, radioactivity level index and gamma dose rates have been evaluated to estimate the radiation hazard levels in the study area. The comparison of obtained concentrations and hazard indices with global data (UNSCEAR. (2008). Sources, effects and risks of ionizing radiation. United nations scientific committee on the effects of atomic radiation (report to the general assembly, with Annexes).) suggests that this region lies in a relatively high background radiation zone.

Estimation of gross α-β and tritium activities in groundwater samples using LSC-TDCR technique in and around the geothermal region of Eastern India

The present study is an attempt to assess the radiogenic quality of groundwater on the basis of gross α, gross β and tritium (3H or H-3) activities in the Bakreswar-Tantloi geothermal region of Chotanagpur Plateau, West Bengal and Jharkhand, India. The aforesaid parameters in groundwater samples were measured using liquid scintillation counting triple to double coincidence ratio (LSC-TDCR) technique. Groundwater samples collected from Bakreswar-Tantloi geothermal region show gross α activities from below the minimum detectable activity (BMDA) to 0.5 ± 0.05 Bq/L, gross β activities from BMDA to 0.2 ± 0.01 Bq/L and H-3 activities from BMDA to 63.42 Bq/L. The average gross α, gross β and H-3 activities are also within the permissible limits prescribed by the World Health Organization (WHO). Though the annual effective doses in some samples were higher than the reference dose level of 0.1 mSv, the overall result suggests that the groundwater in the Bakreswar-Tantloi geothermal region is radiologically safe considering the radionuclides covered in this study.

Green tea leaves extract with low concentration of EGCG can provide health benefits without causing renal damage

Green tea or its concentrated extract is coveted for its health promoting catechin-like polyphenols, especially epigallocatechin-3-gallate (EGCG). However, its amicable efficacy is now being doubted considering the recent occurrence of several cases of hepato- and nephrotoxicity, after the ingestion of EGCG-fortified (≥85–90%) nutritional supplements. Therefore, the current study was carried out to ascertain the effect of green tea leaves extract (GTE), having low EGCG content (73.8%), on liver and kidney functions of male Wistar rats using various in vivo experiments and in vitro radical scavenging activity. In terms of acute toxicity, GTE was observed to be safe when delivered at a dosage of 2000 mg kg−1 body weight (BW). Oral delivery of GTE for 28 days at a concentration of 200 mg kg−1 BW/day did not trigger sub-acute toxicity to the liver and kidneys, as per serum biochemical analyses and histopathological examination. In contrast, GTE counteracted the effects of carbon tetrachloride (a potent hepato-degenerative compound) on the liver. Furthermore, increase in high-density lipoprotein―cholesterol with concomitant lowering of serum triglycerides and low-density lipoprotein―cholesterol were noticed in GTE-treated rats. These findings suggest that low EGCG containing GTE, with appreciable antioxidant activity (IC50 = 53.18–71.28 μg mL−1), can serve as a hepatoprotective, hypolipidemic, and hypocholesterolemic ingredient.

A Non-Fourier Bioheat Transfer Model for Cryosurgery of Tumor Tissue with Minimum Collateral Damage

BACKGROUND AND OBJECTIVES

Incorporation of non-Fourier heat conduction while studying heat transfer phenomena in biological materials has emerged has an important approach as it predicts better and more realistic results than Fourier based models. In this article we have proposed a non-Fourier computational model and applied the same to simulate cryosurgery of lung tumor and attempted minimization of freezing damage of healthy lung tissue using pulsed laser irradiation.

METHODS

A non-Fourier bioheat transfer model for phase change in biological tissues is solved via a Fourier heat conduction based solution approach. A unified model is proposed combining all variants of bioheat models: Fourier's heat conduction based Pennes' bioheat model, hyperbolic heat conduction model and dual phase lag model. The proposed model takes into account the different thermophysical properties of frozen and unfrozen regions. In order to mimic the actual biotransport process, the blood perfusion and metabolic heat generation are switched off in the frozen region. Implicit source based enthalpy method is used to model phase change process. A new iterative enthalpy update equation is developed for capturing evolution of freezing front implicitly. Finite Volume based numerical discretization technique is used to discretize the governing PDE. The resulting discrete algebraic equation set is solved implicitly by Tri-diagonal Matrix Algorithm. The proposed model is verified with existing results from the literature.

RESULTS

For Fourier heat conduction, freezing time of 99.99% of tumor is 1247s, which increases to 1267s for τ_q= 5s (τ_T= 0s) and again reduces to 1255s for τ_q= 5s and τ_T= 3s. τ_q and τ_T are phase lag parameters for non-Fourier heat conduction. For τ_q= 5s and τ_T= 0.05s, the freezing damage of healthy tissue decreases by 23.76% when pulsed laser irradiation (I_o = 10⁶ W/m²) is used to warm the neighboring healthy tissue.

CONCLUSIONS

So non-Fourier bioheat transport models are better and more accurate in predicting temperature history, freezing time and freezing front propagation as compared to Fourier based models. Pulsed laser irradiation can prove to be a very efficient technique in minimizing collateral damage during cryosurgery.

Identification of earthquake precursors in soil radon-222 data of Kutch, Gujarat, India using empirical mode decomposition based Hilbert Huang Transform

Soil radon (Rn-222) has been continuously monitored at Badargadh station (23.47°N, 70.62°E) in Kutch region of Gujarat to study the pre-seismic anomalies prior to occurrence of local earthquakes. This monitoring site is in close proximity to the South Wagad Fault, a seismically active fault in the study area. The raw data of radon along with meteorological parameters such as temperature, pressure and humidity in soil of this station for the period of January 01 to December 31, 2017 with a sampling interval of 10 min were used in the analysis. The wind speed and rainfall data of the corresponding period were collected from the nearest weather station. From descriptive statistics, we found an average soil radon concentration of 343 Bq.m^-3. It is observed that radon has a maximum concentration during the rainy season compared to the other two seasons. We found that radon emission rate is less during mid-nights and early morning, whereas, the radon emission is more during afternoon hours when the sun light intensity is more. In order to identify and extract the periodic oscillations in the radon time series, the Empirical Mode Decomposition (EMD) was applied to the soil radon (Rn-222) time series by decomposing it into different oscillatory modes known as the Intrinsic Mode Function (IMF). Several interesting non-linear features emerged from the analysis after applying Hilbert Huang Transform (HHT) on significant IMFs. The temporal variation of the instantaneous energy is well correlated with four local earthquakes during the study period. Most interestingly, intermittencies in the temporal evolution of the instantaneous energy function have been observed prior to these local earthquakes. We present the results of the seismic and aseismic periods as well as a brief discussion of the analysis of radon data which can be used as a precursor of seismic activity. It is now possible to identify anomalies in radon time series using EMD based HHT method even for small-magnitude earthquakes.

Floral contrivances and specialised pollination mechanism strongly influence mixed mating in Wrightia tomentosa (Apocynaceae)

Reproductive success of a plant species is largely influenced by the outcome of mating pattern in a population. It is believed that a significantly larger proportion of animal-pollinated plants have evolved a mixed-mating strategy, the extent of which may vary among species. It is thus pertinent to investigate the key contributors to mating success, especially to identify the reproductive constraints in depauperate populations of threatened plant species. We examined the contribution of floral architecture, pollination mechanism and breeding system on the extent of outcrossing rate in a near-threatened tree species, Wrightia tomentosa. The breeding system was ascertained from controlled pollination experiments. In order to determine outcrossing rate, 60 open-pollinated progeny were analysed using an AFLP markers. Although the trees are self-compatible, herkogamy and compartmentalisation of pollen and nectar in different chambers of the floral tube effectively prevent spontaneous autogamy. Pollination is achieved through specialised interaction with moths. Differential foraging behaviour of settling moths and hawkmoths leads to different proportions of geitonogamous and xenogamous pollen on the stigma. However, most open-pollinated progeny were the result of xenogamy (outcrossing rate, tm = 0.68). The study shows that floral contrivances and pollination system have a strong influence on mating pattern. The differential foraging behaviour of the pollinators causes deposition of a mixture of self- and cross-pollen to produce a mixed brood. Inbreeding depression and geitonogamy appear to play a significant role in sustaining mixed mating in this species.

Monitoring of soil radon by SSNTD in Eastern India in search of possible earthquake precursor

The present paper deals with monitoring soil radon-222 concentration at two different locations, designated Site A and Site B, 200 m apart at Jadavpur University campus, Kolkata, India, with a view to find possible precursors for the earthquakes that occurred within a few hundred kilometers from the monitoring site. The solid state nuclear track detector CR-39 has been used for detection of radon gas coming out from soil. Radon-222 time series at both locations during the period August 2012-December 2013 have been analysed. Distinct anomalies in the soil radon time series have been observed for seven earthquakes of magnitude greater than 4.0 M that occurred during this time. Of these, radon anomalies for two earthquakes have been observed at both locations A and B. Absence of anomalies for some other earthquakes has been discussed, and the observations have been compared with some earthquake precursor models.