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1.
Environ Toxicol Pharmacol ; 78: 103398, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32361396

RESUMO

The present study was carried out to investigate the impact of various concentrations of SiO2 nanoparticles (SiO2 NP) on the commonly available freshwater fish Oreochromis mossambicus. The 96 h median lethal concentration (LC50) of SiO2 NP was found to be between 270-280 ppm. This novel study has demonstrated histological alterations in the hepatic tissues and a dose-dependent depletion of tissue protein content and an elevated transaminases activity in the treated fish, which has facilitated understanding of the impact of SiO2 NP in O. mossambicus.


Assuntos
Fígado/efeitos dos fármacos , Nanopartículas/toxicidade , Dióxido de Silício/toxicidade , Tilápia , Poluentes Químicos da Água/toxicidade , Animais , Proteínas de Peixes/metabolismo , Fígado/metabolismo , Fígado/patologia , Tilápia/metabolismo
2.
J Family Med Prim Care ; 8(3): 1134-1137, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31041263

RESUMO

BACKGROUND: Supraglottic airway devices are used for anesthesia in elective surgical procedures circumventing the need for intubation. We investigated the efficacy and safety of Baska® mask in comparison to an I-Gel® device. METHODS: In this cross-sectional, observational study, we randomized 100 female patients (age 18-45 years, American Society of Anaesthesiologists grade I or II) undergoing elective short gynecological procedures into two groups, to receive ventilation with either Baska mask® (group 1, n = 50) or an I-Gel® device (group 2, n = 50). We excluded patients with obesity, short neck, and known systemic and upper airway disorders. The primary outcome was the oropharyngeal airway seal pressure, and the secondary outcomes were the ease of insertion and the complication rate. The results were analyzed using Mann-Whitney U-test and Fisher's exact test, and correlation analysis was done by Spearman's correlation test. RESULTS: A total of 56 patients underwent dilatation and curettage, whereas the remaining had hysteroscopy in the study. The airway seal pressure achieved was higher with Baska® mask than I-Gel® device (35.8 ± 10.3 and 26.9 ± 7.5 of cm H2O, respectively; P < 0.0001). The ease of insertion (P < 0.0001) was better in group 1 and the complication rates were similar in both the groups (P > 0.05). CONCLUSION: Baska® mask offers a superior airway seal pressure with minimum complications in comparison to an I-Gel® device. Further studies with a large number of patients in different surgical settings are required to confirm our findings.

3.
Int J Radiat Biol ; 95(6): 753-763, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30822214

RESUMO

Purpose: The effect of low level cobalt-60 (60Co) gamma radiation on the freshwater prawn Macrobrachium rosenbergii was evaluated by observing their hemocyte counts and biochemical parameters. Materials and methods: Prawns were exposed to 3, 30, 300 and 3000 milligray (mGy) dose levels and their tissues of gills, hepatopancreas and muscle were analyzed. Results: The results showed that the number of hemocytes in the hemolymph and concentrations of protein and carbohydrate were significantly reduced in irradiated groups than compared to the control prawn. Increased aspartate transaminase (AST), alanine transaminase (ALT), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), Acetyl choline esterase (AChE) in the irradiated groups reflects tissue damage. Conclusions: Hence, this study concludes that even low level of ionizing radiation (60Co gamma) can cause acute damages in gills, hepatopancreas and muscles in irradiated groups. Highlights 60Co exposures effect the THC and biochemical of prawn M. rosenbergii. Different dose levels such as 3, 30, 300 and 3000 mGy. Biochemical parameters serve as reliable indicators of physical status of organism. Self-regulating mechanisms might be the reason for preventing from the lethality. Suggested that nuclear industries should manage below 3 mGy.


Assuntos
Radioisótopos de Cobalto/efeitos adversos , Raios gama/efeitos adversos , Hemócitos/citologia , Hemócitos/efeitos da radiação , Palaemonidae/efeitos da radiação , Animais , Metabolismo dos Carboidratos/efeitos da radiação , Contagem de Células , Palaemonidae/citologia , Palaemonidae/metabolismo
4.
Environ Toxicol Pharmacol ; 66: 55-61, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30597380

RESUMO

The present study was aimed to analyze the effect of ZnO and TiO2 nanoparticles (NPs) on Haemato-immunological parameters in adult Tilapia, Oreochromis mossambicus. The nanoparticles size found as 47 nm and 30 nm for ZnO and TiO2 respectively. The acute toxicity (96 h) of ZnO (LC50: 100-110 ppm) and TiO2 (LC50: 80-90 ppm) NPs were identified by using probit analysis. RBC, Hb and HCT levels decreased in nanoparticles exposed groups resulted in decreased oxygen carrying capacity of RBC and other erythrocyte indices (MCH, MCV, MCHC). Increased WBC, neutrophils & monocytes and decreased lymphocyte levels were observed as increased concentration of the nanoparticles. The results were found as statistically significant (p < 0.05). In conclusion, the present study depicts that ZnO NPs exhibits more toxicity than TiO2 NPs. Nanoparticles presence even in low concentration (ppm) cause damage to the connective tissues of fish, so the existing permissible levels of these nanoparticles in water are need to be revised.


Assuntos
Nanopartículas/toxicidade , Tilápia/sangue , Titânio/toxicidade , Poluentes Químicos da Água/toxicidade , Óxido de Zinco/toxicidade , Animais , Feminino , Testes Hematológicos , Dose Letal Mediana , Masculino , Tilápia/imunologia
5.
Environ Toxicol Pharmacol ; 59: 74-81, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29544187

RESUMO

In the present study, freshwater fish Oreochromis mossambicus were exposed to sub lethal concentrations (120, 150 and 180 ppm) of Aluminium oxide nanoparticles (Al2O3 NPs) for 96 h. Histological abnormalities were not observed in the organs of control fishes whereas severe damages and extensive architectural loss was found in the brain, gill, intestine, kidney and muscle tissues of treated fishes with more pronounced effects in 180 ppm. The results showed that the acute exposure to Al2O3NPs altered the histoarchitecture in various fish tissues.


Assuntos
Óxido de Alumínio/toxicidade , Nanopartículas/toxicidade , Tilápia , Poluentes Químicos da Água/toxicidade , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Brânquias/efeitos dos fármacos , Brânquias/patologia , Intestinos/efeitos dos fármacos , Intestinos/patologia , Rim/efeitos dos fármacos , Rim/patologia , Microscopia Eletrônica de Transmissão , Músculos/efeitos dos fármacos , Músculos/patologia , Nanopartículas/ultraestrutura
6.
Mar Pollut Bull ; 127: 541-547, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29475695

RESUMO

Comparative study of trace metals distribution in the surface sediment of Sundarban mangrove ecosystem in India and Bangladesh is one of the primary baseline study done so far. Trace metal distribution assessment covering lower salinity zone to higher salinity zone was done along Matla River (tidal river) in Indian side and freshwater zone to higher salinity zone along Passur River in Bangladesh side of Sundarban; representing anthropogenic influenced area, agricultural area, tourist site and pristine area. Trace metals distribution in the surface sediments of Sundarban mangrove ecosystem shows relatively higher value of trace metals, Co, Cr, Cu, Fe, Ni, Pb and Zn in Indian part when compared to Bangladesh. Enrichment factor shows the highest enrichment of Pb in both parts of Sundarban mangroves. Co, Cr, Cu, Pb and Zn show EF>1 indicates sediment contamination from anthropogenic activities. Cr, Ni and Pb were found to have moderate accumulation in geoaccumulation index with Fe showing high accumulation. Normalized data of trace metals shows 87.5% from Indian site and 80% of Bangladesh site as outlier, indicating anthropogenic influence. Out of total sampling site 50% of Indian and 40% of Bangladesh site show trace metal values enriched more than predicted value of trace metals indicating Indian part have more polluted sites than Bangladesh side of Sundarban, which is also confirmed by enrichment factor, I-geo and normalization values in both the sides.


Assuntos
Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Metais Pesados/análise , Oligoelementos/análise , Poluentes Químicos da Água/análise , Áreas Alagadas , Bangladesh , Índia , Rios/química
7.
J Trace Elem Med Biol ; 44: 125-131, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28965567

RESUMO

Adverse effects of nanoparticles on aquatic environment and organisms have drawn much special attention to many researches. Aluminium oxide nanoparticles (Al2O3-NPs) have potential uses in varied fields and are seen entering into the ecosystem. Their potential toxicity to the freshwater fish is not much studied. Hence this study was framed to investigate the effect Al2O3 NPs on freshwater fish Oreochromis mossambicus in terms of sub lethal toxicity, histological changes and hepato somatic index (HSI) under laboratory conditions. Fishes were exposed to varying concentrations of Al2O3 NPs for 96hr. LC50 value was found to be in between 235 and 245ppm. The findings of the present work showed that the NPs were accumulated in the fish liver and caused major histological anomalies such as structural alterations in the portal vein, necrotic hepatocytes, vacuolation, aggregation of blood cells and melanomacrophages. Significant histological alterations were observed in the highest concentration. Our results evidenced that the Al2O3 NPs in the aquatic environment affects the health condition of the fishes.


Assuntos
Óxido de Alumínio/toxicidade , Água Doce , Fígado/patologia , Nanopartículas/toxicidade , Tilápia/fisiologia , Animais , Fígado/irrigação sanguínea , Fígado/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Nanopartículas/ultraestrutura , Pâncreas/efeitos dos fármacos , Pâncreas/patologia , Veia Porta/efeitos dos fármacos , Veia Porta/patologia , Testes de Toxicidade Aguda , Difração de Raios X
8.
Mar Pollut Bull ; 118(1-2): 112-124, 2017 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-28238488

RESUMO

A study on vertical distribution of magnetic susceptibility, carcinogenic and endocrine disrupting PAHs was performed in the reclaimed mudflat sediments adjacent to the Thane Creek of Mumbai. The 5-rings PAHs and ΣC-PAHs were more dominant at 120cm depth contributing 52.23% and 60.19% respectively to ∑PAHs. The average ratio values of LMW/HMW PAHs (0.58); Fla/(Fla+Pyr) (0.50); Ant/(Ant+Phe) (0.50); BaA/(Chry+BaA) (0.48); BaP/BghiP (2.06), Phe/Ant (1.03) and BaA/Chr (0.93) indicate that the PAH contamination might have raised due to inefficient combustion and pyrogenic emissions during the open burning of solid waste in the vicinity. This was further supported by the anthropogenic ferri(o)magnetic loading over the last 100years influencing the Creek sediments. The PAHs toxicity estimation was performed by calculating the toxic equivalent quantity (TEQ) value of 8.62ng TEQ/g which was below the safe level (600ng TEQ/g) suggested by the Canadian risk-based soil criterion for protection of human health.


Assuntos
Monitoramento Ambiental , Sedimentos Geológicos/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise , Carcinógenos/análise , Disruptores Endócrinos/análise , Humanos , Índia , Solo/química
9.
Appl Radiat Isot ; 122: 121-126, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28130980

RESUMO

Alpha spectra were acquired with Quantulus 1220 liquid Scintillation Counter (LSC) and correlations among parameters, such as alpha particle energy, sample quenching, peak's centroid and resolution were established. The effect of quenching and factors such as types of counting vials, extractive reagents and composition of extractive scintillation cocktail on alpha spectral resolution, was experimentally studied.

10.
Int J Radiat Biol ; 90(2): 179-86, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24279367

RESUMO

PURPOSE: An experiment was carried out to determine the effect of low dose gamma radiation on germination, plant growth, nitrogen and carbon fixation and carbon flow and release characteristics of groundnut. MATERIALS AND METHODS: Dry seeds of groundnut variety Trombay groundnut 37A (TG 37A), a radio mutant type developed by Bhabha Atomic Research Centre (BARC), Mumbai, India, were subjected to the pre-sowing treatment of gamma radiation within low to high dose physiological range, i.e., 0.0, 0.0082, 0.0164. 0.0328, 0.0656, 0.1312, 5, 25, 100, 500 Gray (Gy) from a cobalt source ((60)Co). Observations were recorded for the radiation effect on percentage germination, vigour, gas exchange attributes such as photosynthetic rate, stomatal conductance and transpiration rate, chlorophyll content, root exudation in terms of (14)C release, vascular sap flow rate and activities of rate defining carbon and nitrogen assimilating enzymes such as ribulose-1,5-bisphosphate carboxylase (rubisco) and nitrate reductase (NR). RESULTS: Seed germination was increased by 10-25% at the lower doses up to 5 Gy while the improvement in plant vigour in the same dose range was much higher (22-84%) than the unirradiated control. For radiation exposure above 5 Gy, a dose-dependent decline in germination and plant vigour was measured. No significant effect was observed on the photosynthesis at radiation exposure below 5 Gy but above 5 Gy dose there was a decline in the photosynthetic rate. Stomatal conductance and transpiration rate, however, were only inhibited at a high dose of 500 Gy. Leaf rubisco activity and NR activities remained unaffected at all the investigated doses of gamma irradiation. Mean root exudation and sap flow rate of the irradiated plants, irrespective of the dose, was reduced over the unirradiated control more so in a dose-dependent manner. CONCLUSIONS: Results indicated that a very low dose of gamma radiation, in centigray to gray range, did not pose any threat and in fact stimulated metabolic functions in such a way to aid growth and development of groundnut plants. It further showed that the radiation threshold for the gas exchange traits and rubisco activity, which ultimately determine the plant health and yield, were higher than compared to the other metabolic attributes and were well beyond 500 Gy and that the dose range above 500 Gy should be targeted to measure lethal effects of radiation on carbon assimilation attributes in leguminous crops, in general, and groundnut in particular.


Assuntos
Arachis/efeitos da radiação , Raios gama , Arachis/metabolismo , Relação Dose-Resposta à Radiação , Germinação/efeitos da radiação , Nitrato Redutase/metabolismo , Folhas de Planta/efeitos da radiação , Ribulose-Bifosfato Carboxilase/metabolismo
11.
Aquat Toxicol ; 144-145: 36-49, 2013 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-24140570

RESUMO

This study was framed to investigate the (60)Co gamma radiation induced morphological and histological variations in freshwater prawn Macrobrachium rosenbergii. The LD50 value of (60)Co gamma irradiated M. rosenbergii observed (by probit analysis) at 30 Gy. Prawns were irradiated to four different dose levels (3 mGy, 30 mGy, 300 mGy and 3,000 mGy) using Theratron Phoenix TeleCobalt Unit [P-33] and one control group (without irradiation) maintained separately. Irradiated groups exhibited several morphological variations such as discoloration; damaged rostrum; opaque coloration in cephalothorax; black bands and dot formation in abdomen; deformed uropods and telson in tail regions when compared with control group. The Hepato Somatic Index reflected the severity of radiation on hepatopancreas. Histological variations in gills, hepatopancreas and muscles of irradiated groups were observed. In gills, structural changes such as swollen and fused lamellae, abnormal gill tips, hyperplasic, necrotic and clavate-globate lamellae were observed in gamma irradiated prawns. Accumulation of hemocytes in hemocoelic space, interstitial sinuses filled with abnormal infiltrated hemocytes, the tubular epithelium with ruptured basal laminae, abnormal and coagulated lumen, necrotic tubules, thickened basal laminae, tissue debris, necrotic hepatocytes were observed in irradiated prawn hepatopancreas. In muscle, shrinkage of muscular fiber and necrotic musculature were observed in irradiated prawns. These structural alterations of the organs it is felt could affect the vital physiological functions such as respiration, osmotic and ionic regulation in gills and muscles; absorption, storage and secretion of the hepatopancreas which in turn could adversely affect the growth and survival of freshwater prawn M. rosenbergii.


Assuntos
Radioisótopos de Cobalto , Poluentes Ambientais/toxicidade , Raios gama , Palaemonidae/efeitos da radiação , Animais , Brânquias/efeitos da radiação , Hepatopâncreas/efeitos da radiação , Dose Letal Mediana , Músculos/efeitos da radiação , Palaemonidae/anatomia & histologia , Palaemonidae/citologia
12.
Ecotoxicol Environ Saf ; 92: 155-60, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23587558

RESUMO

Present study was designed to observe the effects of (60)Co gamma radiation in behavioral and histological changes in the gills of giant fresh water prawn Macrobrachium rosenbergii. The adult prawns were irradiated with four different dose levels (3mGy, 30mGy, 300mGy and 3000mGy) and the control group (without irradiation) was maintained separately. Behavioral changes like hyperactivity, loss of balance, reduced swimming rate, slower rate of food intake and convulsions were observed in higher dose levels of 300mGy and 3000mGy. The histological alterations such as accumulated haemocytes in haemocoelic spaces, abnormal gill tips, lifted lamellar epithelium, swollen and fused lamellae, hyperplasic, necrotic, clavate-globate and complete disorganization of lamellae were observed in (60)Co gamma irradiated prawns. Significantly more considerable histological alterations were observed in the highest dose level of 3000mGy, but no mortality was evidenced. This study serves as biomonitoring tool to assess the radiation pollution in the aquatic environment.


Assuntos
Radioisótopos de Cobalto/toxicidade , Brânquias/efeitos da radiação , Palaemonidae/efeitos da radiação , Poluentes Radioativos da Água/toxicidade , Animais , Água Doce , Brânquias/patologia , Hemócitos/efeitos da radiação
13.
J Environ Radioact ; 113: 57-62, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22634030

RESUMO

The irradiation effect of (60)Co at the three dose level of 3 mGy, 30 mGy and 300 mGy on the histology of liver of the freshwater fish Oreochromis mossambicus was investigated. The liver of O. mossambicus was dissected out and processed for light microscopy studies. (60)Co exposed O. mossambicus were found to result in several alterations in the histoarchitecture of liver. The alterations included mild congestion of blood vessels, structural alteration, cellular swelling, vacuolation and necrotic liver cells, indicating a definite response to (60)Co irradiation. The results suggest that the liver of O. mossambicus exposed to (60)Co were structurally altered with increasing dose levels. It is to record that alteration in the liver does not affect the physiology, behaviour or lethality of the individuals. Self regulating mechanisms would have influenced the liver to remain sustained. To confirm the same further studies in the direction by increasing dose level is required.


Assuntos
Radioisótopos de Cobalto/toxicidade , Fígado/patologia , Fígado/efeitos da radiação , Tilápia/metabolismo , Animais , Água Doce
14.
Anal Methods ; 3(3): 622-627, 2011 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32938082

RESUMO

ThO2 with approximately 3% 233UO2 is the proposed fuel for the Advanced Heavy Water Reactor (AHWR) and characterized as a mixed oxide (MOX) fuel. Due to the existence of a single oxidation state, quantitative dissolution of MOX samples like (Th-U)O2 and (Th-Pu)O2 is a challenging task for any analytical chemist. However, dissolution is a pre-requisite for complete characterization of the fuel. The present paper describes a detailed study carried out on the comparison of dissolution of sintered (Th-U)O2 mixed oxide pellets, in 16 M HNO3 using microwave and conventional heating techniques, under reflux conditions. The study was carried out with variation of parameters such as concentration of HF and UO2 substitution in the MOX solid solution. The concentration of dissolved U and Th was determined by modified Davies and Gray potentiometric titration and Th-EDTA complexometric titration using xylenol orange as the titration end point indicator respectively. Experimental results clearly indicate that the microwave heating assisted dissolution rate is 2 to 3 times higher than the conventional infrared heating assisted dissolution rate, for sintered pellets. The concentration of HF is a critical parameter, an excess leads to precipitation of insoluble ThF4. The concentration of HF was optimized to 0.025 M. Experimental results also clearly show that at this concentration of HF in 16 M HNO3, a higher substitution of UO2 in MOX solid solution also facilitates the dissolution process. Different trace metal impurities were determined in the MOX samples after dissolving by microwave and infra red heating techniques and it was observed that the results are comparable.

15.
Radiat Prot Dosimetry ; 133(4): 214-22, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19339303

RESUMO

In order to meet the proposed regulatory compliances for the protection of non-human species from the ionising radiation, a comprehensive dose-evaluation process for terrestrial and aquatic biota was worked out at Trombay. During this work, dose rate (external and internal) from ionising radiation to the terrestrial plants and marine organisms (mixed varieties of fish) was evaluated by estimating the concentration of anthropogenic ((137)Cs, (90)Sr) and natural radionuclides ((238)U, (232)Th and (40)K) in environmental matrices, such as soil, vegetation, sea water and sediment. The samples were processed as per the International Atomic Energy Agency protocol for the estimation of naturally occurring and anthropogenic radionuclides. The average values of radiation exposure to the terrestrial plants for (40)K, (90)Sr, (137)Cs, (232)Th and (238)U were 632.8 +/- 40.5, 167.4 +/- 48.2, 691.2 +/- 29.9, 48769 +/- 13203 and 1801 +/- 1495 microGy y(-1), respectively. In the case of marine organisms (fish), the maximum external exposure was 195 microGy y(-1) due to (40)K concentration in bottom sediment, whereas the minimum was 0.004 microGy y(-1) due to (137)Cs in sea water. Internal exposure to fish was maximum (700 microGy y(-1)) due to (40)K, whereas the minimum of 0.12 microGy y(-1) was due to (90)Sr. Considering the dose limit of 10 mGy d(-1) (3.65 Gy y(-1)), proposed by the US Department of Energy, evaluated radiation exposure (external + internal) and dose rate in the present study to the terrestrial plants and marine organisms are orders of magnitude less.


Assuntos
Biodiversidade , Sedimentos Geológicos/análise , Plantas/efeitos da radiação , Monitoramento de Radiação , Poluentes Radioativos do Solo/análise , Poluentes Radioativos da Água/análise , Índia , Radiação Ionizante , Espectrometria gama
16.
Appl Radiat Isot ; 67(4): 501-5, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19128979

RESUMO

During this work, controlled redox potential methodology was adopted for the complete separation of traces of uranium from the host matrix of mixed hydroxide of Iron. Precipitates of Fe(+2) and Fe(+3) along with other transuranic elements were obtained from acid leached solution of soil by raising the pH to 9 with 14N ammonia solution. The concentration of the uranium observed in the soil samples was 200-600 ppb, whereas in sediment samples, the concentration range was 61-400 ppb.

17.
J Phys Condens Matter ; 20(27): 275205, 2008 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-21694367

RESUMO

We report an investigation of Mn-doped ZnO pellets with diluted Mn concentration by soft-x-ray emission and absorption spectroscopy. We have compared the electronic structure of two samples with different Mn concentration and different magnetic properties at room temperature: ferromagnetism in one case (Zn(0.98)Mn(0.02)O) and no magnetic order in the other (Zn(0.96)Mn(0.04)O). The results show that most of the Mn ions of the ferromagnetic sample are in the divalent state. For the nonmagnetic sample, a larger contribution of higher oxidation Mn states is present, which can be correlated to the suppressed ferromagnetism. The presence of oxygen atoms bonded to Mn ions and hybridized Mn 3d-O 2p states has been detected in both compounds. The partial density of states in the valence band has been measured with x-ray emission spectroscopy and the Mn 3d states have been found inside the bandgap of ZnO.

18.
Radiat Prot Dosimetry ; 124(4): 378-84, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17545658

RESUMO

During this study, non-parametric statistical methods were used to validate the measured gamma dose rate with the calculated one, around Trombay. Portable dose rate digital gamma spectrometry system (target fieldSPEC) was used for in situ measurement of external gamma (gamma) dose rate (measured) with the range of 1 nSv/h-10 Sv/h. The activity concentration of U-238, Th-232, K-40 and Cs-137 in the soil and their respective external dose-conversion factor (nSv/h/Bq/kg) was used to evaluate the gamma dose rate (calculated). Non-parametric statistical tool like Box- and -Whisker Plot, Spearman's (rho) rank Correlation coefficient, the Wilcoxon/Mann-Whitney test and chi(2) distribution test have been applied for validation. The randomness or discrete behaviour of measured and calculated dose rate was obvious from the Box- and -Whisker Plot as mean and median of the two are not equal. The inter quartile range (Q3-Q1), which explains about the dispersion of measured and calculated dose rate were also evaluated and found to be 10 and 16 microSv/y, respectively. The linear association between the order of ranks of the two dose rates was established by using Spearman's (rho) rank correlation that showed a coefficient of R = +0.90 with the intercept +1.9, whereas Pearson's correlation was observed with a coefficient of R = +0.93 with the intercept -25.6. Wilcoxon/Mann-Whitney test shows that, medians of the calculated and the measured dose rate as significantly different under the assumption of null hypothesis and measured dose rate was made to the normal distribution by applying Z-statistics. Value of chi(2) was calculated and found to be 284.95, which was very much greater than the critical value of chi(2)(0.05) = 43.77 at a degree of freedom 30, concluding that there is a highly significant difference between the measured and calculated dose rate at 5% significance level.


Assuntos
Exposição Ambiental/análise , Raios gama , Poluentes Radioativos do Solo/análise , Estatísticas não Paramétricas , Contaminação Radioativa do Ar/análise , Humanos , Índia , Espectrometria gama
19.
Environ Int ; 32(2): 224-8, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16199088

RESUMO

During this work, size fractionation technique "ultra filtration" is used in speciation studies of trace elements in the coastal sea water. Filtration is the most commonly used method to fractionate trace metal species, but often only "dissolved" and "particulate" fraction. The purpose of the present study is to determine colloidal and suspended particulate concentrations of Fe, Zn, Cu, Ni, and Mn in sea water. Suspended particulate matter were separated in three different size groups namely (>2.7 microm, <2.7->0.45 microm and <0.45->0.22 microm) by suction filtration using cellulose acetate and nitrate filter membranes. Thereafter to concentrate the solution with colloidal particle <0.22 microm-1.1 nm (0.5 k Nominal Molecular Weight cut-off Limit {NMWL}), the solution obtained from filtration through <0.22 microm, is sequentially passed through the ultra-filtration membranes having pore diameters of 14 nm (300 k NMWL), 3.1 nm (50 k NMWL), 2.2 nm (30 k NMWL), 1.6 nm (10 k NMWL) and 1.1 nm (0.5 k NMWL) by using Stirred Ultra-filtration Cells, operating in concentration mode. The concentration of Fe, Zn, Cu, Ni, and Mn were measured in suspended and dissolved fraction by ion chromatography, ICP-AES and Atomic Absorption Spectrometer. The salinity of the solution in various dissolved fractions of sequential filtration varies between 30.89-34.22 parts per thousand. The maximum concentrations of colloidal Zn, Cu, Ni and Mn in dissolved fraction were in <2.2->1.6 nm fraction. In case of Fe, colloidal fractions <2.2->1.6 nm and <1.6-<1.1 nm shows higher concentration. The concentration of Zn, Cu, Ni and Mn increase with decrease in size in suspended particulate matter, while the reverse is observed in case of Fe. This size separation data that specifies the partitioning of metals between dissolved and suspended solid phases is necessary for developing physically based models of metal transport in aquatic system.


Assuntos
Monitoramento Ambiental/métodos , Metais Pesados/análise , Poluentes Químicos da Água/análise , Benzopiranos , Coloides/análise , Coloides/classificação , Substâncias Húmicas , Tamanho da Partícula , Água do Mar , Ultrafiltração
20.
J Synchrotron Radiat ; 8(Pt 2): 818-20, 2001 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-11512943

RESUMO

Intercalation effect on BSCCO (2212) system, although it increases the interlayer distance and the c-axis remarkably, produces only a small change in the transition temperature. Thus, amongst other things, intercalation provides an effective method to investigate the influence of the interblock coupling. Electrons are transferred from the host Cu-O2 layers to the guest molecules I2, HgBr2, HgI2 leading to evolution of the Tc. For this we have made high resolution XANES study on the O K and Cu L3 edges to estimate the density of the doping holes. We attempt on basis of our and earlier results the evolution of Tc in these as also the much larger decrease produced in Tc for I2-intercalation for which the increase in basal spacing is the smallest of the three halides.

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