Facile synthesis of hierarchical nickel (III) oxide nanostructure: A synergistic remediating action towards water contaminants

Heavy metal ion removal from consumable water is an indispensable need to maintain healthy life. Therefore cost effective and highly efficient sorbents are strongly needed to pose threat to real water pollution. Nanomaterials are widely used to maintain clean aqueous system in a very cost effective way with high removal efficiency. In this present work, pure coral like Ni₂O₃ nanostructures were prescribed for Cr(VI) remediation which were prepared by two step synthesis procedure at room temperature. The single hierarchical morphology as confirmed from HRTEM (size∼200 nm) were subjected to toxic Cr(VI) ion removal experiments. They were found to remove ∼65% Cr(VI) ions that was higher than that of pure Ni₂O₃ nanoparticles of comparable size. The enhanced properties were explained on the basis of the defect states present within the nanostructure, investigated by positron annihilation lifetime spectroscopy (PALS). It was found that the hierarchical nanostructure had more number of di-vacancies and vacancy-clusters as compared to the particles. On performing isotherm fitting, it was found that the coral like morphology had a high heterogeneity factor that aided to a high adsorption rate when compared to the pure Ni₂O₃ nanoparticles (which had a homogenous surface). The synthesized nanostructure was severely toxic to bacterial community having minimum inhibitory concentration (MIC) of ∼300 μg/L. Also the nanostructure exhibited dual functionality towards Cr(VI) and bacteria contaminated water at 200 μg/ml. The maximum Cr(VI) removal efficiency for this dual system is found to be 39% whereas antibacterial activity was turned out to be 30% which was extensively higher than that of toxic Cr(VI) ions. A plausible mechanism for the dual functionality was also predicted.

Respiratory effect related to exposure of different concentrations of arsenic in drinking water in West Bengal, India

Arsenic toxicity due to drinking of arsenic contaminated water has been one of the worst environmental health hazards. High levels of arsenic have been reported in different natural water sources from West Bengal for more than two decades. Groundwater contamination by arsenic and its adverse effects on the health of a big population in nine districts of West Bengal have been reported. The problems found were mainly related to skin and respiratory, digestive, cardiovascular and nervous systems. The respiratory effects are largely confined to those who had the skin lesion. The present study was undertaken to evaluate the respiratory effects of exposure to different levels of arsenic in drinking water. The water samples were collected from different tube wells and wells in the study area. Analysis of arsenic was done by Atomic Absorption Spectrophotometer with hydride generation system. Based on the consumption of arsenic concentrations in drinking water the populations were divided into three categories, i.e., <=50 microg/L, >50 - <= 150 microg/L and >150 microg/L. Standard techniques of medical examination were applied to elicit signs and recorded in the pre-designed proforma. A written consent was taken from each subject for their voluntary participation in the study. 112 subjects were investigated. The respiratory effect was evaluated by measuring the pulmonary function test (PFT). Vital Capacity (VC) and Forced Vital Capacity (FVC) were measured by Spirovit-SP-10 (Schiller Health Care Pvt Ltd., Switzerland) and Peak Expiratory Flow Rate by Wrights Peak Flow Meter (Clement and Clarke, UK). The PFT values showed gradual decrement among the males following skin pigmentation, keratosis and arsenicosis. The respiratory function impairment among the male subjects found as restrictive type (26.41%), obstructive type (3.77%) and combined type (7.54%), whereas in females only the restrictive type of impairment (10.16%) was found. Restrictive type of impairments among the subjects increased as the concentration of arsenic in drinking water increased, in males 15.78%, 29.41% and 35.29% and in females 4.54%, 5.00% and 23.52% respectively. The pathophysiologic mechanism, by which ingested arsenic leads to impairments of lung function and increased respiratory symptoms, is yet to be understood and needs further investigation.

Pulmonary function in aluminium smelter and surrounding community--a case study

The increase of industrial activities in the Angul-Talcher area, Orissa resulted in indiscriminate disposal of waste into the environment leading to the deterioration of the quality of the environment, which affects the health of the workers as well as the community people. Considering the magnitude of the problem, the pulmonary function study had been carried out in one of the largest aluminium producing plant of the country as well as surrounding community people. Aluminium is produced from oxides of alumina by Hall-Heroult smelting process. The electrolysis called as aluminium smelting is carried out in an electrolytic cell (pot) having anode, cathode and electrolyte. The aluminium is deposited in the cathode and the oxygen moves towards anode is released. The workers working at the captive power plant (CPP), which is necessary to meet the power demand of the smelter plant were also investigated. 180 smelter plants workers (non-smoker 129, smoker-51) of different sections and 37 captive power plant workers (non-smoker 29, smoker-8) had undergone pulmonary function tests. Besides these, 85 persons from the surrounding community (non-smoker-66, smoker-19) were also investigated. The workers were all male. Spirometric assessments of Vital Capacity (VC), Forced Vital Capacity (FVC), and Peak Expiratory Flow Rate (PEFR) were done by Spirovit-sp-10 (Schiller Health Care Ltd, Switzerland) and Wrights Peak flow meter (Clement and Clarke, UK). Different lung volumes like FEV1, FEV1%, and flow rates like FEF200-1200ml, FEF25-75% and FEF75-85% were calculated from the same tracings pulmonary function test (PFT) results of the workers according to different age groups, duration of exposures and smoking habits. The mean values of SVC, FVC and FEV1 of smelter plant workers were found higher compared to the community people but the values of captive power plant workers were very much close to the values of the community people. A gradual decrement of the PFT values was found as duration of exposure increased. Lung volumes and the flow rates were decreased as age increases but in some age groups that trend was not followed. It has been found that in each category of subjects, smokers have the higher mean pulmonary function values compared to the non-smokers. Except the community people in all other cases the different flow rates were found higher in nonsmokers compared to smokers. The restrictive, obstructive and combined restrictive and obstructive types of impairments among the subjects were noticed. The respiratory impairment among the workers as a whole was found higher in smelter plant workers (9.44%) followed by the captive power plant workers (5.40%) and the community people (2.35%). In smelter plant workers both the restrictive and obstructive impairments were found higher compared to captive power plant and the community people.

A study on blood eosinophil level and ventilatory pulmonary function of the workers exposed to storage grain dust

The workers engaged in storage grain handling are exposed to storage grain dust and suffer from different respiratory symptoms like, cough wheezing, chest tightness, eye and nasal irritations. It has been reported abroad and the present study results noted that the grain handlers have allergic symptoms like redness of eyes, itching, sneezing, skin rash, breathlessness and decrement of pulmonary function test values. According to their nature of job, the workers of storage grain godowns were divided into four categories i.e., load handling worker (LHW), ancillary, quality control and depot administration workers. The pulmonary function tests (PFT) and the differential count of leucocytes were carried out among the workers by standard technique. Decrement of pulmonary function test values was noted with the increment of blood eosinophil level.

The PFT results were presented according to the blood eosinophil level. The decrement of mean PFT values were noticed as the blood level of eosinophil gradually increased from, up to -4%, >4-10% and above 10%. The maximum numbers of workers in different job categories are belonged to >4 -10% of eosinophil level. The percentage figure of workers in different departments were LHW 48.38%, (n=45), ancillary 38.88%, (n=7), quality control 54.54% (n=6) and depot administration workers 47.05% (n=16) are belonged to that range. Among the total workers the higher figure was found >4-10% ranges 47.43% (n=74) workers. The allergic manifestations like redness, itchiness and watering of eyes, sneezing, cough, breathless etc. are reported. These workers have blood eosinophil level and low pulmonary function test values. The respiratory impairments among the workers are restrictive, obstructive and combined restrictive and obstructive type.

Respiratory health status of the roadside school children at Kolkata

School students in metro cities are often exposed to vehicle exhausts as their schools are situated mostly on the high traffic roadside. Acute exposure to automobile exhaust is associated with increased respiratory symptoms and may decrease and impair lung function in children. The lung functioning performance of the city school children was compared with rural school children where there is no pollution and automobile exhausts. In Kolkata, two schools for boys (n = 210) and two schools for girls (n = 200) and in rural area one school for boys (n = 99) and the other school for girls (n = 95) were investigated. City schools are situated on the main roadside, nearer to the traffic junction. The detail histories about health status of children, if they have any subjective feelings of health related problems during the school hours or after returning from the school, and the family histories were taken by questionnaire method. The pulmonary function tests (PFT) were carried out by Spirometric method by Spirovit-Sp-10 and Wright's Peak flow meter. The mean PFT values of the students found in the normal range. Boys were having higher values compared to the girls in both city and rural schools. Lung volumes and flow rates were significantly higher in rural students. Symptomatic changes like breathlessness, cough and other problems (sneezing, eye irritation, running nose etc.) among city schoolboys found 13%, 7% and 15% and in girls found 12%, 6% and 7% respectively. In symoptomatic students, mean PFT values were significantly lowered compared to non-symptomatic. PFT values were presented in relation to age and height. It has been found that a number of city school students are having different types of respiratory symptoms. Long-term effect of exposure into such environment may develop lung functional impairments.

Environmental pollution in rural areas of Orissa state due to industrial emissions--with special reference to fluoride

Angul - Talcher belt in Central Orissa, having a number of industries contributing to a great extent to deteriorate the air quality of the surrounding villages. Previous reports showed higher SPM, SO2, NO, levels in air and prevalence of respiratory illness, skin and teeth disorders among village population. Higher ground water fluoride, urine and serum fluoride among the cattle were also reported in some villages. Present study reports SPM, SO2, NOx and Fluorides (gaseous and Particulate) in ambient air around aluminium smelter during February and August 1996. High volume sampling technique for SPM and the standard colorimetric methods (BIS) for analyses of SO2 and NOx were adopted. Fluoride in air and water were estimated by standard fluoride ion selective electrode method. Higher SPM, SO2 and NOx values than prescribed CPCB standard were obtained in February. Gaseous fluoride in village air were varied between, 1.66 - 7.64 mg/m3 in February and 1.11 - 22.75 mg/m3 in August, whereas particulate fluoride ranged between, 0.054 - 19.61 mg/m3. Water sources of the villages near the smelter showed fluoride values above permissible limit. The study indicated higher fluoride pollution in air and water of the surrounding villages.

Pulmonary Function Abnormalities Associated with Exposure to Automobile Exhaust in a Diesel Bus Garage and Roads

In Kolkata city the road transports are maintained by private and Government organization. A major work force belonged to the State Transport Corporation (KSTC), Government of West-Bengal. The pollution caused by these vehicles affects the workers health and caused different types of respiratory problems. This study was undertaken to assess the pulmonary function status of these workers. City KSTC garage workers were investigated and categorically divided into two group: garage mechanics and the (2) those transporting the passengers (drivers and conductors). Vital capacity (VC), forced vital capacity (FVC) and peak expiratory flow rate (PEFR) were recorded by Spirovit-SP-10 (Schiller Ltd, Switzerland) and Wright's Peak Flow Meter (UK) on 236 workers. The different flow volumes, FEV(1), FEV(1%), and flow rates, FEF(02-121), FEF(25-75%), etc. were calculated. The administrative people had higher PFT than the other categories. Drivers and conductors have almost equal mean PFT values but mechanical workers had slightly higher. PFT values according to different age ranges and duration of exposure showed gradual decrement as age and duration of exposure increased. Non-smokers had higher lung volumes compared to smokers and ex-smokers. Restrictive, obstructive and combined types of impairments were noticed in 28.4%, 1.7% and 2.9%, respectively, workers. The restrictive impairment was found to be 30.4% in conductors; 28.9% in drivers, 27.9% in mechanics and 21.7% in administration people. Obstructive type of impairment was found to be 2.9% in both drivers and conductors. The effect of pollution by dust and fumes may be responsible for these pulmonary function impairments, restrictive impairments being greater.

Propagation of dust-acoustic waves in a bounded dusty plasma

The linear and nonlinear propagation of dust-acoustic waves in a dusty plasma bounded in finite geometry has been theoretically investigated. It is found that the finite geometry of the bounded plasma makes a significant contribution to the instability of the wave. Moreover, the pseudopotential has a positive and inverted profile that prevents the trapping of particles and does not favor solitary waves in bounded dusty plasma.

A 3-D FEM analysis of single and multiple screw-root dental implant fixed in a mandible

Replacement of single tooth using a threaded titanium screw root coated with hydroxyapatite (HA) for faster bone apposition to implant site is common. Uncoated pure titanium is also used for osseointegration. Usually bone fixation of implant takes four to six months in either case. Quite often, a good number of teeth in a mandible or maxilla are replaced. Usually it is often said that bones appear to be well designed from the point of view of structural engineering. The "maximum-minimum law" claimed by Roux is a rational concept that states that bone provides maximum strength with a minimum of construction material. According to this proposition, stress distribution in bone will be almost uniform under a set of loading conditions. This was found to be true in the case of normal human mandibular bone as examined by some Japanese scientists. The present authors are interested in examining the stress distribution during multiple single tooth replacements using 3D-FEM technique to ascertain how the stress pattern changes with such implantation of three screws in a row in the human mandible, as we are in the process of clinical trial of hydroxyapatite coated and uncoated titanium implant. This will be of considerable interest to the dental surgeons, who prompted us to address this problem. Our results depicted the mean values of various stress in cortical and cancellous bone while applying the maximum masticatory load of 50 N in each teeth. The generated stress level is within the safe range of stress for bones. However, such screws cannot be applied to osteoporotic or other diseased mandible where bone strength may be quite low.

Stress analysis of an artificial temporal mandibular joint

To design a temporal mandibular joint (TMJ), the designer should pay attention to the range of movement in the joint, the strength of the joint, and the size of the implant should conform, so that it does not hamper facial configuration. As a number of designs are available, in this study we have considered one of the most common and widely used implants for analysis. The main objective of this study is to examine the stress-strain behavior at the implant and what is happening at the implant bone interface. We have also examined whether implant material can be replaced by UHMWPE (ultra high molecular weight polyethylene) instead of titanium or Co-Cr-Mo alloy. Whether the change of positions of the screw used for fixation has any effect or not, we have modeled it considering actual shape and size, then divided it into number finite elements by using a FEM package. An appropriate surgical construct was modeled and loaded and studied for different parameters. We have shown that the metallic prostheses are good from a stress-strain point of view and UHMWPE cannot be used as such.

Blood donation and risk of post-transfusion hepatitis

A survey was conducted among 300 blood donors of urban and rural population (the Sunderbans) and paid donors to evaluate the nutritional status, serum proteins, immunoglobulin and alanine aminotransferase (ALT) on the persistence of carrier state for post-transfusion hepatitis (PTH). Paid donors showed lowering of serum albumin and elevation of immunoglobulin and ALT. Nutritional and immunoglobulin profiles of rural donors of the Sunderbans, differed from those of voluntary donors of urban area. In the presence of subclinical hepatitis, ALT measurement alone is not a reliable guide for identification of individual carriers.