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Biomedical subjects

B Bhattacharya

Publications and source records attributed to B Bhattacharya.

At least 19 recordsLinked to original sources

Machine learning in soil classification.

In a number of engineering problems, e.g. in geotechnics, petroleum engineering, etc. intervals of measured series data (signals) are to be attributed a class maintaining the constraint of contiguity and standard classification methods could be inadequate. Classification in this case needs involvement of an expert who observes the magnitude and trends of the signals in addition to any a priori information that might be available. In this paper, an approach for automating this classification procedure is presented. Firstly, a segmentation algorithm is developed and applied to segment the measured signals. Secondly, the salient features of these segments are extracted using boundary energy method. Based on the measured data and extracted features to assign classes to the segments classifiers are built; they employ Decision Trees, ANN and Support Vector Machines. The methodology was tested in classifying sub-surface soil using measured data from Cone Penetration Testing and satisfactory results were obtained.

Algorithms↗

Machine learning in sedimentation modelling.

The paper presents machine learning (ML) models that predict sedimentation in the harbour basin of the Port of Rotterdam. The important factors affecting the sedimentation process such as waves, wind, tides, surge, river discharge, etc. are studied, the corresponding time series data is analysed, missing values are estimated and the most important variables behind the process are chosen as the inputs. Two ML methods are used: MLP ANN and M5 model tree. The latter is a collection of piece-wise linear regression models, each being an expert for a particular region of the input space. The models are trained on the data collected during 1992-1998 and tested by the data of 1999-2000. The predictive accuracy of the models is found to be adequate for the potential use in the operational decision making.

Algorithms↗

Immunogenetic association and thyroid autoantibodies in juvenile autoimmune thyroiditis in North India.

OBJECTIVES: Autoimmune thyroid diseases (AITD) encompass a number of conditions that have in common cellular and humoral responses targeting the thyroid gland. Interactions between susceptibility genes and environmental triggers are thought to initiate an autoimmune response to thyroid antigens leading to disease manifestation. Commencement of the disease in childhood leads to the presumption that genetics may have an important role in the causation of the disease. DESIGN: The present study was aimed at evaluating the human leucocyte antigen (HLA) encoded susceptibility to develop juvenile autoimmune thyroiditis (JAT) in patients from North India. PATIENTS: We studied 48 consecutive patients of JAT along with 176 first-degree relatives for their thyroid function (FT4, TSH) and anti-thyroid peroxidase antibody status (AbTPO). MEASUREMENTS: HLA studies were carried out using serology for HLA-class I antigens and DNA analysis of HLA-class II alleles. The data were compared with a cohort of 308 ethnically matched healthy individuals. RESULTS: We observed overt hypothyroidism in 50% and AbTPO positivity in 70.8% of the index cases. Among the first-degree relatives, goitre was observed in 51.7%, thyroid dysfunction in 28.4% and AbTPO in 29.5% of individuals. Of the 37 relatives who underwent fine-needle aspiration cytology (FNAC), 60% had evidence of chronic lymphocytic thyroiditis (CLT). A strong positive association of HLA-DRB1*1404 was observed with the JAT (35.4%vs. 10.4%, chi2 = 19.8, Pc = 0.0001). We also observed a higher (72%, P = 0.03) paternal transmission of HLA-DRB1*1404 to affected offspring in comparison to unaffected offspring. HLA-DRB1*03 was also increased among JAT patients but did not reach statistical significance. CONCLUSION: These studies point towards an important role of immune modifying genes, such as HLA, in influencing susceptibility to juvenile-onset AITD.

Adolescent↗

Most commercial insulin assays fail to detect recombinant insulin analogues.

Insulin assays are utilized in various clinical scenarios, including the assessment of insulin therapy compliance or of suspected insulin overdose. In an interpretative exercise carried out by UK National External Quality Assessment Service (NEQAS), serum sent to the participating laboratories was spiked with 30 pmol/L of the short-acting insulin analogue Human Actrapid. Only two out of 24 participant laboratories had sufficient assay cross-reactivity with Actrapid to interpret the results as suggestive of insulin administration. The development of specific insulin assays has led to deterioration in the ability to detect non-compliance or overdose with recombinant insulin treatment. Clinicians should be aware of this significant limitation, which could lead to misdiagnosis.

Adolescent↗

Relation between increased anaerobic glycolysis and visual acuity in long-standing type 2 diabetes mellitus without retinopathy.

In long-standing diabetes mellitus, blood flow to essential organs including the retina is reduced owing to macrovascular and/or microvascular changes. Poor glycolytic pathway of glucose metabolism owing to tissue hypoxia caused by ischemia at capillary bed of essential organs produces excessive lactic acid and less of adenosine triphosphate, which lead to poor cellular function. The purpose of the study was to evaluate the relationship between increased anaerobic glycolysis and visual acuity in type 2 diabetes mellitus without retinopathy. Fifty patients of type 2 diabetes mellitus of 10-12 years duration, without retinopathy, constituted the study group. The controls were 50 age-matched healthy persons without diabetes mellitus. Blood lactate level and best-corrected visual acuity (BCVA) were measured in both the groups. The mean blood lactate level was 1.05 mM/l in the control group and 2.32 mM/l in the study group. BCVA of 20/20 (log MAR 0) was seen in 48 (96%) patients of the control group and in 27 (54%) patients of the study group. BCVA of 20/30 (log MAR 0.2) was seen in 23 (46%) patients in the study group and 2 (4%) in the control group. Association of higher blood lactate level with decreased BCVA in the study group was statistically significant (P< 0.001).

Anaerobic Threshold↗

Coexistent partial anodontia and supernumerary tooth in the mandibular arch: a rare case.

Coexistent partial anodontia and supernumerary tooth in the lower jaw is a very uncommon condition. Very few cases have been reported in the literature of this condition, etiology of which is still obscure. Presented here is a rare case of simultaneous presence of single supernumerary tooth together with missing permanent central incisor teeth in the lower jaw without any associated systemic condition or syndrome.

Anodontia↗

Role of cytosolic phospholipase A2 in the enhancement of alpha2-adrenoceptor-mediated vasoconstriction by the thromboxane-mimetic U46619 in the porcine isolated ear artery: comparison with vasopressin-enhanced responses.

Pre-contraction with the thromboxane-mimetic U46619 enhances the subsequent alpha(2)-adrenoceptor-mediated vasoconstriction in the porcine ear artery through an enhanced activation of ERK-MAP kinase. In this study we determined the role of cPLA(2) in this enhanced response, and determined whether vasopressin is also able to enhance alpha(2)-adrenoceptor-mediated vasoconstriction through the same pathway. The cPLA(2) inhibitors AACOCF3 (50 microM) and MAFP (50 microM) both inhibited the U46619-enhanced alpha(2)-adrenoceptor response, but had no effect on the direct alpha(2)-adrenoceptor response. AACOCF3 also inhibited the enhanced ERK activation associated with the enhanced alpha(2)-adrenoceptor-mediated vasoconstriction. Pre-contraction with arachidonic acid mimicked the effect of U46619 by enhancing the contractile response to the alpha(2)-adrenoceptor agonist UK14304 (1 microM) and enhancing the alpha(2)-adrenoceptor-mediated ERK activation. Pre-contraction with vasopressin also enhanced the contractile response to UK14304, but neither PD98059 (50 microM) nor AACOCF3 (50 microM) had any effect this vasopressin-enhanced response, indicating that neither the ERK pathway, nor cPLA(2) are involved in vasopressin-enhanced responses. The alpha(2)-adrenceptor-stimulated activation of ERK was also unaffected by pre-contraction with vasopressin. On the other hand, inhibition of PKCzeta inhibited the enhanced alpha(2)-adrenoceptor contraction after pre-contraction with both U46619 and vasopressin. This study demonstrates that alpha(2)-adrenoceptor-mediated vasoconstriction can be enhanced through two different pathways-one dependent upon the enhanced activation of ERK-MAP kinase through activation of cPLA(2), and the other through a different, ERK/cPLA(2)-independent pathway.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗

Interspecific variation in heavy metal body concentrations in biota of Sunderban mangrove wetland, northeast India.

The coastal environment of West Bengal, recognized as the most diversified and productive ecosystem among all the maritime states of India, faces organic pollution from domestic sewage and urban and industrial effluents leading serious impacts on biota. The present paper aims at providing information on concentration level of heavy metals among the tissues of benthic polychaetes, bivalve molluscs and finfishes collected from Sundarban mangrove wetland, northeast coast of India. An overall common trend in bioaccumulation was revealed with the following decreasing order: Zn>Mn>Cu>Cr>Se>Hg with few exceptions. Both species dependent variability and temporal variations were pronounced. A high degree of organ specificity was evident in the bivalves where gill and mantle exhibited higher metal accumulation due to ion exchange property of the mucous layer covering these organs. Variability between closely related species is a reflection of different uptake rates, physiology and impact of environmental factors. The results of this analysis suggest that mollusks can play a significant role in trace metal trophic transfer studies, especially as their representatives are intertidally and subtidally ubiquitous.

Animals↗

Deep Impact: observations from a worldwide Earth-based campaign.

On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass to gas mass in the ejecta was much larger than before impact; (iii) the new activity did not last more than a few days, and by 9 July the comet's behavior was indistinguishable from its pre-impact behavior; and (iv) there were interesting transient phenomena that may be correlated with cratering physics.

Cosmic Dust↗

Erupted maxillary conical mesiodens in deciduous dentition in a Bengali girl--a case report.

Mesiodens is a midline supernumerary tooth commonly seen in the maxillary arch. It is the most significant dental anomaly affecting permanent dentition mainly and primary dentition rarely. It may occur as an isolated dental anomalous condition or may be associated with a syndrome. Many theories have been promulgated to explain its etiology. But an exact etiology is still obscure. Incidence of mesiodens in children varies from 0.15 to 3.8%. Boys are affected more (2:1) than girls. Morphologically, mesiodens may be of three types: the most commonly seen is conical, while tuberculate and supplementary types.

Child, Preschool↗

The efficacy of topical administration of brimonidine to reduce ischaemia in the very early stage of diabetic retinopathy in good controlled type-2 diabetes mellitus.

It is now proved that diabetic micro-angiopathy is caused by ischaemia at the capillary bed of retina due to reduced capillary blood flow in long standing type-2 diabetes mellitus. Deranged metabolic process due to chronic hypoxia at the tissue level produces visual and vascular dysfunction. Brimonidine tartrate, an alpha-2 agonist which is commonly used in glaucoma to protect retinal ganglion cells from pressure related ischaemia induced cell apoptosis, is administered in very early stage of non-proliferative diabetic retinopathy to reduce ischaemia at the capillary bed of retina. Improved visual acuity and decreased micro-aneurysm formation, which indicate elimination of ischaemic stimulus at the tissue level, are seen in long standing type-2 diabetes mellitus.

Aneurysm↗

Enhancement of alpha2-adrenoceptor-mediated vasoconstriction by the thromboxane-mimetic U46619 in the porcine isolated ear artery: role of the ERK-MAP kinase signal transduction cascade.

1. Alpha(2)-adrenoceptor-mediated contractions in porcine blood vessels can be enhanced in the presence of the thromboxane-mimetic U46619, and forskolin. The aim of this study was to determine the role of U46619 in the enhanced contractions, and to determine whether signalling through the ERK-MAP kinase pathway is involved. 2. Responses to the alpha(2)-adrenoceptor agonist UK14304 (1 micro M) were increased from 22+/-3% of the response to 60 mM KCl to 68+/-12% (n=8, mean+/-s.e.m.) in the presence of a low concentration of U46619 (< 20% of the 60 mM KCl response). 3. Both the direct and the U46619-enhanced UK14304 responses were inhibited by 50 microM PD98059, an inhibitor of the ERK-MAP kinase pathway. UK14304-induced contractions were associated with an increase in ERK2 phosphorylation, indicating an increased activity. In the presence of U46619, there was an enhanced phosphorylation of ERK2. U46619 on its own had no effect on ERK phosphorylation. 4. Both the direct and enhanced UK14304 contractions were inhibited in the absence of extracellular calcium. These conditions also prevented the increase in ERK2 phosphorylation. This indicates a role for calcium influx in the enhanced contractions. 5. In conclusion, this study demonstrates that precontraction with the thromboxane-mimetic U46619 enhances alpha(2)-adrenoceptor-mediated vasoconstriction through the enhancement of the ERK-MAP kinase pathway, and influx of extracellular calcium.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗

The river Ganga of northern India: an appraisal of its geomorphic and ecological changes.

The Ganga is the most important perennial river originating from Gangotri in the snow-bound Himalayas about 3,900 m above mean sea level. Gorging a distance of about 220 km in the Himalayas, it enters the plain at Hardwar and after meandering and braiding over a distance of about 2,525 km through the Indo-Gangetic plains, ultimately joins the Bay of Bengal. The course of this river has been changed due to: (i) subsurface geotectonic movement leading to change in slope of the deltaic plain and subsidence of the Bengal basin; (ii) changing pattern of water discharge with time; (iii) variations in sediment load. The environment of Ganga basin is also deteriorating with time due to severe natural episodes of periodic floods and storms as well as anthropogenic factors such as population growth, deforestation, agricultural activities, urbanisation, fertiliser and fossil fuel consumption and construction activities such as dams and bridges. All these have inconceivable adverse impacts on the health and natural regeneration capacity of the river basin. The presence of micropollutants in water and sediments of this river turns the system into being unsustainable to the biota. The present study synthesises the available information on the changes of its geological, geomorphological and ecological aspects and suggests some remedial measures to be adopted now and in future.

Agriculture↗

Short-term REM sleep deprivation effect on temperature rhythm of rats.

Circadian rhythm of body temperature (CRT) is altered in endogenous depression and many psychiatric disorders. Even the sleep pattern is disrupted. Sleep deprivation alleviates symptoms in depression. The present study was conducted to find the role of noradrenergic innervation to the pineal gland in bringing about the effect of REM sleep deprivation (REMSD) on the CRT. Adult male Wistar rats (n = 12) divided into 2 groups were used for the study. The group I rats (n = 6) underwent superior cervical ganglionectomy and the group II rats (n = 6) were sham ganglionectomised. After recovery rats were given REMSD for 48 hours. The CRT was measured in three periods of the study i.e. basal, post operative and post REMSD. The results indicated REMSD increased the Amplitude and Mesor of the CRT in both the groups which was shortlasting and reversible thus suggesting non sympathetic mediation of the pineal in bringing about the circadian rhythm alteration due to REMSD.

Animals↗