The pulsatile blood flow through constricted artery generates fluid mechanical forces on internal layer of artery, endothelium. These fluid mechanical factors affect endothelial lining from keeping ...artery healthy. In this paper, a series of numerical simulations of modeled bell shaped stenosed artery have been carried out for investigation of fluid mechanical factors of realistic pulsatile flow at the inlet of modeled stenosis with bell shaped geometry. The governing equations for two-dimensional unsteady laminar flow of incompressible fluid are solved by finite volume method followed by SIMPLER algorithm. The fluid mechanical factors, particularly wall pressure, streamline contour, peak wall shear stress, low wall shear stress and oscillatory shear index, having inferences to the arterial disease, are investigated by simulation results of different percentage of restrictions. All these parameters have a noticeable impact for the plaque deposition. The impacts of Reynolds number and Womersley number for both of mild stenosis and severe stenosis on arterial disease, atherosclerosis are also investigated by evaluating fractional flow reverse and oscillatory shear potential.
Background: In India, substance abuse has infiltrated all
socio-cultural and economic strata causing loss of
productivity.Prevention of relapse is crucial for its control.
Objectives: To find out the ...pattern of substance use, relapse rate, its
association with various socio-demographic factors and treatment
related issues. Methods: An observational study with cross-sectional
design during April 2009-March 2010 at a de addiction centre was
conducted among consecutive 284 clients admitted with relapse. They
were detoxified earlier in the same centre. Data were collected by
interviewing clients with schedule and clinical examination. Results:
Brown sugar (an adulterated form of Heroin) was primary drug of abuse
in urban area contrary to alcohol in rural area. Commonest age of
initiation was between 15-20 years. Polydrug abusers (59.1%) were
common. Only 31.3% of the relapse cases took regular follow up. Common
psychiatric illnesses were anxiety (44.7%) and depression (30.6%). Peer
pressure (77.8%) was commonest cause of relapse. Significantly higher
relapse episodes were present with increasing age,Muslim religion, ever
marriage, poor literacy, current unemployment, living in nuclear rather
than joint family, early age of initiation, longer duration of abuse
and no follow up. Conclusion: Regular follow up with family, peer and
social support are essential along with vocational rehabilitation to
prevent relapse.
In this paper, performance simulation of a hybrid diffuser, hybrid diffuser with suction and hybrid diffuser with fence have been carried out. The two-dimensional steady differential equations for ...conservation of mass and momentum have been solved for the Reynolds number ranging from 100 to 600. During the simulation, a fixed aspect ratio of 2 and a fixed value of half divergence angle of 3.5° have been considered for all the diffuser geometries. At the inlet, fully developed velocity profile has been used. The effect of Reynolds number on average static pressure have been studied in detail, and compared between three diffuser geometries. The effective diffuser lengths for achieving maximum average static pressure at the diffuser exit have been computed for the considered Reynolds numbers.
In the present paper, the effect of symmetrical and asymmetrical bell-shaped stenoses on wall pressure drop, streamline contour, and rise in wall shear stress for the progression of the disease, ...atherosclerosis has been investigated numerically. The governing equations have been solved by finite volume method. Both steady and pulsatile flow at inlet is considered in our study. It is revealed from the study that the impact of wall pressure and peak wall shear stress on progression of disease are always high for asymmetrical shaped stenosis for both steady and pulsatile flow. The impact of asymmetrical shape on plaque deposition zone is less, if the aggravation changes the shape of stenosis due to change in stricture length only keeping percentage of restriction same. Whereas, the impact of asymmetrical shape on plaque deposition zone will be high, if shape of stenosis changes by increasing both stricture length and percentage of restriction for both steady and pulsatile flow. Impact of pulsatile nature of flow on the aggravation of disease is higher at some timesteps in comparison to steady flow.
Purpose - This paper aims to perform numerical simulations through different shaped double stenoses in a vascular tube for a better understanding of arterial blood flow patterns, and their possible ...role during the progression of atherosclerosis. The dynamics of flow features have been studied by wall pressure, streamline contour and wall shear stress distributions for all models.Design methodology approach - A finite volume method has been employed to solve the governing equations for the two-dimensional, steady, laminar flow of an incompressible and Newtonian fluid.Findings - The paper finds that impact of pressure drop, reattachment length and peak wall shear stress at each restriction primarily depends upon percentage of restriction, if restriction spacing is sufficient. The quantum of impact of pressure drop, reattachment length and peak wall shear stress is much effected for smaller restriction spacing. If recirculating bubble of first restriction merges with the recirculating bubble formed behind the second restriction in this smaller restriction spacing. The similar effect of smaller restriction spacing is observed, if Reynolds number increases also.Originality value - The effect of different shaped stenoses, restriction spacing and Reynolds number on the flow characteristics has been investigated and the role of all the flow characteristics on the progression of the disease, atherosclerosis, is discussed.
Background: Cold chain maintenance is an essential activity to maintain
the potency of vaccines and to prevent adverse events following
immunization. One baseline study highlighted the unsatisfactory ...cold
chain status in city of Kolkata in India. Objectives: To assess the
changes which occurred in the cold chain status after the intervention
undertaken to improve the status and also to assess the awareness of
the cold chain handlers regarding cold chain maintenance. Methods:
Intervention consisted of reorganization of cold chain points and
training of health manpower in Kolkata Municipal area regarding
immunization and cold chain following the guidelines as laid by the
government of India. Reevaluation of cold chain status was done at 20
institutions selected by stratified systematic random sampling after
the intervention. The results were compared with baseline survey.
Results: Significant improvement had been observed in correct placing
of cold chain equipment, maintenance of stock security, orderly placing
of ice packs, diluents and vaccines inside the equipment, temperature
recording and maintenance. But awareness and skill of cold chain
handlers regarding basics of cold chain maintenance was not
satisfactory. Conclusions: The success of intervention included
significant improvement of cold chain status including creation of a
designated cold chain handler. The gaps lay in non-availability of
non-electrical cold chain equipment and separate cold chain room, which
policy makers should stress. Cold chain handlers need reorientation
training regarding heat and cold sensitive vaccines, preventive
maintenance and correct contingency plan.
The medical and economic problem of thalassaemia are considered to be a vast public health problem in the thalassaemia belt countries, emphasizing more on prenatal diagnosis as the solution of the ...problem.
A cross-sectional descriptive study was conducted in the Institute of Haematology & Transfusion Medicine located in Medical College, Kolkata, India to assess the socio-demographic profile, clinical presentation, expenditure for treatment of thalassaemia patients and awareness about cause and prevention of the disease.
Thalassaemia patients attended the Govt. setting were mostly from lower socioeconomic status with low level of literacy. Annual expenditure for treatment of thalassaemia ranged from $ 108 to 432; depending on type of treatment with average cost per transfusion was $ 5.2±2.2. Average 18.5%±14.3 of the total annual income was spent on the treatment for thalassaemia. Average man days or school days lost for the patients was 29.87±18.5 and 19.07±12.7 for the accompanying persons.
Blood transfusion and carrier screening facilities should be decentralized to decrease the expenditure for treatment and alleviate the harassment of the families. Folate and calcium tablets, hepatitis B vaccination can be made available at government setting free of cost.
Numerical solutions of the steady viscous flow in the neighborhood of different double stenoses are obtained under laminar flow conditions with the motivation for modeling blood flow through stenosed ...artery formed due to arterial disease. The flowing blood is considered to be incompressible and Newtonian. A finite volume method has been employed to solve the governing equations. The dynamics of flow features have been studied by wall pressure, streamline contour, and wall shear stress distributions for all models. The results have demonstrated that when the shapes of stenosis change at primary stenosis keeping no change in the shape of secondary stenosis, the impact of changes in primary stenosis on secondary one is noted to be more, whereas, no impact of primary stenosis on secondary stenosis and vice versa is observed in case of changes in the shapes of secondary stenosis keeping no change in the shape of primary stenosis. When Reynolds number changes, the impact of changes in primary stenosis on secondary one is also noted to be higher.
Noise is a major health threat in occupations where its level exceeds the permissible level (90dB). Most serious health effect is Noise Induced Hearing Loss (NIHL). Objective of the present study was ...to find out any relationship between occupational noise exposure and hearing impairment of the employees in a heavy engineering industry.
A cross-sectional study was conducted during May 2005 to April 2006 in a selected heavy engineering industry in Kolkata. All the employees working in the factory were included in the study. Data were collected through interview, physical examination, audiometry and environmental noise survey.
Among the total of 278 employees of this study, 235 employees were exposed above the permissible occupational noise level (90dB), out of whom 82 (34.90%) employees were deaf which was much more than the deafness among the nonexposed workers 3 (6.98%). Hearing impairment increased as exposure level increased and this was statistically significant (chi2 = 17.97, df = 2, p = 0.0001). Hearing impairment also increased with duration of exposure (chi2 = 7.12, df = 2, p = 0.0284).
Hearing impairment is associated with occupational noise exposure and thus pre-placement and periodical medical examination is of vital importance.
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