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1.
IEEE Access ; 8: 177647-177666, 2020.
Article in English | MEDLINE | ID: mdl-34786292

ABSTRACT

Rapid spread of Coronavirus disease COVID-19 leads to severe pneumonia and it is estimated to create a high impact on the healthcare system. An urgent need for early diagnosis is required for precise treatment, which in turn reduces the pressure in the health care system. Some of the standard image diagnosis available is Computed Tomography (CT) scan and Chest X-Ray (CXR). Even though a CT scan is considered a gold standard in diagnosis, CXR is most widely used due to widespread, faster, and cheaper. This study aims to provide a solution for identifying pneumonia due to COVID-19 and healthy lungs (normal person) using CXR images. One of the remarkable methods used for extracting a high dimensional feature from medical images is the Deep learning method. In this research, the state-of-the-art techniques used is Genetic Deep Learning Convolutional Neural Network (GDCNN). It is trained from the scratch for extracting features for classifying them between COVID-19 and normal images. A dataset consisting of more than 5000 CXR image samples is used for classifying pneumonia, normal and other pneumonia diseases. Training a GDCNN from scratch proves that, the proposed method performs better compared to other transfer learning techniques. Classification accuracy of 98.84%, the precision of 93%, the sensitivity of 100%, and specificity of 97.0% in COVID-19 prediction is achieved. Top classification accuracy obtained in this research reveals the best nominal rate in the identification of COVID-19 disease prediction in an unbalanced environment. The novel model proposed for classification proves to be better than the existing models such as ReseNet18, ReseNet50, Squeezenet, DenseNet-121, and Visual Geometry Group (VGG16).

2.
Data Brief ; 13: 460-468, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28702485

ABSTRACT

This paper presents an experimental study on the development of polymer bio-composites. The powdered coconut shell, walnut shells and Rice husk are used as reinforcements with bio epoxy resin to form hybrid composite specimens. The fiber compositions in each specimen are 1:1 while the resin and hardener composition 10:1 respectively. The fabricated composites were tested as per ASTM standards to evaluate mechanical properties such as tensile strength, flexural strength, shear strength and impact strength are evaluated in both with moisture and without moisture. The result of test shows that hybrid composite has far better properties than single fibre glass reinforced composite under mechanical loads. However it is found that the incorporation of walnut shell and coconut shell fibre can improve the properties.

3.
Lancet ; 383(9911): 40-47, 2014 Jan 04.
Article in English | MEDLINE | ID: mdl-24035220

ABSTRACT

BACKGROUND: A serogroup A meningococcal polysaccharide-tetanus toxoid conjugate vaccine (PsA-TT, MenAfriVac) was licensed in India in 2009, and pre-qualified by WHO in 2010, on the basis of its safety and immunogenicity. This vaccine is now being deployed across the African meningitis belt. We studied the effect of PsA-TT on meningococcal meningitis and carriage in Chad during a serogroup A meningococcal meningitis epidemic. METHODS: We obtained data for the incidence of meningitis before and after vaccination from national records between January, 2009, and June, 2012. In 2012, surveillance was enhanced in regions where vaccination with PsA-TT had been undertaken in 2011, and in one district where a reactive vaccination campaign in response to an outbreak of meningitis was undertaken. Meningococcal carriage was studied in an age-stratified sample of residents aged 1-29 years of a rural area roughly 13-15 and 2-4 months before and 4-6 months after vaccination. Meningococci obtained from cerebrospinal fluid or oropharyngeal swabs were characterised by conventional microbiological and molecular methods. FINDINGS: Roughly 1·8 million individuals aged 1-29 years received one dose of PsA-TT during a vaccination campaign in three regions of Chad in and around the capital N'Djamena during 10 days in December, 2011. The incidence of meningitis during the 2012 meningitis season in these three regions was 2·48 per 100,000 (57 cases in the 2·3 million population), whereas in regions without mass vaccination, incidence was 43·8 per 100,000 (3809 cases per 8·7 million population), a 94% difference in crude incidence (p<0·0001), and an incidence rate ratio of 0·096 (95% CI 0·046-0·198). Despite enhanced surveillance, no case of serogroup A meningococcal meningitis was reported in the three vaccinated regions. 32 serogroup A carriers were identified in 4278 age-stratified individuals (0·75%) living in a rural area near the capital 2-4 months before vaccination, whereas only one serogroup A meningococcus was isolated in 5001 people living in the same community 4-6 months after vaccination (adjusted odds ratio 0·019, 95% CI 0·002-0·138; p<0·0001). INTERPRETATION: PSA-TT was highly effective at prevention of serogroup A invasive meningococcal disease and carriage in Chad. How long this protection will persist needs to be established. FUNDING: The Bill & Melinda Gates Foundation, the Wellcome Trust, and Médecins Sans Frontères.


Subject(s)
Meningitis, Meningococcal/prevention & control , Meningococcal Vaccines , Neisseria meningitidis, Serogroup A/isolation & purification , Adolescent , Adult , Age Distribution , Carrier State/diagnosis , Carrier State/epidemiology , Carrier State/prevention & control , Chad/epidemiology , Child , Child, Preschool , Epidemics , Humans , Incidence , Infant , Meningitis, Meningococcal/diagnosis , Meningitis, Meningococcal/epidemiology , Population Surveillance/methods , Vaccination , Young Adult
4.
Ghana Med J ; 48(2): 112-22, 2014 Jun.
Article in English | MEDLINE | ID: mdl-25667560

ABSTRACT

The presumptive approach was the World Health Organisation (WHO) recommended to the management of malaria for many years and this was incorporated into syndromic guidelines such as the Integrated Management of Childhood Illnesses (IMCI). In early 2010 however, WHO issued revised treatment guidelines that call for a shift from the presumptive to the test-based approach. Practically, this implies that in all suspected cases, the diagnosis of uncomplicated malaria should be confirmed using rapid test before treatment is initiated. This revision effectively brings to an end an era of clinical practice that span several years. Its implementation has important implications for the health systems in malaria-endemic countries. On the basis of research in Ghana and other countries, and evidence from program work, the Ghana National Malaria Control Program has issued revised national treatment guidelines that call for implementation of test-based management of malaria in all cases, and across all age groups. This article reviews the evidence and the technical basis for the shift to test-based management and examines the implications for malaria control in Ghana.


Subject(s)
Malaria/diagnosis , Malaria/prevention & control , Ghana , Humans , Parasitology/methods
5.
Clin Microbiol Infect ; 17(11): 1617-23, 2011 Nov.
Article in English | MEDLINE | ID: mdl-21951597

ABSTRACT

With declining transmission of malaria in several regions of the world and renewed interest in the elimination of malaria, strategies for malaria control using antimalarial drugs are being revisited. Drug-based strategies to reduce transmission of malaria need to target the asymptomatic carriers of infection. Drugs that are effective against gametocytes are few in number, but it may be possible to reduce gametocyte production by killing the asexual stages, for which more drugs are available. Drugs for use in large-scale programmes must be safe and tolerable. Strategies include improving access to treatment for malaria with an efficacious drug, intermittent-treatment programmes, and mass drug administration, with and without screening for malaria. Recent proposals have targeted high-risk groups for interventions. None of the strategies has been rigorously tested with appropriate control groups for comparison. Because of the lack of field evidence, modelling has been used. Models have shown, first, that for long-lasting effects, drug administration programmes should be linked with vector control, and second, that if elimination is the aim, programmes are likely to be more successful when applied to smaller populations of a few thousand or less. In order to sustain the gains following the scaling up of vector control and use of artemisinin combination therapies (ACTs), strategies that use antimalarials effectively need to be devised and evidence generated for the most cost-efficient way forward.


Subject(s)
Antimalarials/administration & dosage , Disease Transmission, Infectious/prevention & control , Malaria/drug therapy , Malaria/prevention & control , Animals , Carrier State/drug therapy , Carrier State/epidemiology , Carrier State/prevention & control , Drug Therapy/methods , Humans , Insect Control , Malaria/epidemiology
6.
Acta Bioeng Biomech ; 13(1): 77-84, 2011.
Article in English | MEDLINE | ID: mdl-21500767

ABSTRACT

In the last decades, researchers have developed new materials to improve the quality of human life. Owing to the frequent occurrence of bone fractures, it is important to develop plate materials for the fixation of fractured bones. These plate materials have to be lightweight, compatible with human tissues and ought to allow stiffness. Natural fibers have the advantage that they are renewable resources and have marketing appeal. The Asian markets have been supplying natural fibers for many years, e.g., sisal, banana and roselle are common reinforcement in India. In this research, the fabrication of plate material from powdered natural fibers like sisal (Agave sisalana), banana (Musa sapientum) and roselle (Hibiscus sabdariffa), with bio-epoxy resin Grade 3554A and Hardner 3554B, using moulding method, is described. The present work deals with the prediction of flexural rigidity of the NFRP composite which is compared with that obtained using the ANSYS solution. They are found to be in good agreement. In this work, microstructure is scanned by the scanning electron microscope. The objective of this research was to utilize the advantages offered by renewable resources for the development of biocomposite materials based on biopolymers and natural fibers. In the future, this plate material externally coated with calcium phosphate and hydroxyapatite (hybrid) composite can be used for inside fixation and also external fixation of fractured bones.


Subject(s)
Biocompatible Materials/chemistry , Bone Substitutes , Bone Transplantation/methods , Absorption , Biomechanical Phenomena , Biopolymers/chemistry , Cellulose/chemistry , Epoxy Resins , Fracture Healing , Humans , Materials Testing , Microscopy, Electron, Scanning/methods , Models, Chemical , Musa , Plants/chemistry
7.
Trop Med Int Health ; 14(9): 1003-10, 2009 Sep.
Article in English | MEDLINE | ID: mdl-19558374

ABSTRACT

We discuss the potential public health impact of IPTi by estimating the cases of malaria, anaemia and hospital admissions likely to be averted in different transmission settings; and we review the mechanism of action, choice of drugs regimens, and the effect on immunity of IPTi. IPTi using an efficacious drug is likely to substantially reduce cases of clinical malaria in moderate to high transmission settings. However, geographical heterogeneity in malaria transmission could hamper rolling out IPTi as a national policy.


Subject(s)
Anemia/prevention & control , Antimalarials/therapeutic use , Malaria/prevention & control , Preventive Health Services/standards , Anemia/epidemiology , Anemia/immunology , Drug Administration Schedule , Female , Humans , Infant , Malaria/epidemiology , Malaria/immunology , Malaria/transmission , Male , Models, Theoretical
8.
Asia Pac J Public Health ; 19(1): 14-7, 2007.
Article in English | MEDLINE | ID: mdl-17784654

ABSTRACT

This study compares the role and performance of active case detection (ACD) and passive case detection (PCD) in Jepara district, Indonesia. The number of blood slides examined and positive for malaria reported from 1994-1998 was retrieved from the district surveillance registers. Age of cases, parasite species, types of drugs and dosage, and time lapse were recorded from malaria registers at the three most endemic health centres. The quality of diagnosis was examined by re-reading 153 slides at the Department of Parasitology, Faculty of Medicine, Gadjah Mada University. Almost 60% of the 10,493 confirmed cases in Jepara district were identified from ACD. ACD detected significantly higher P. falciparum gametocyte infections than PCD (14.7% vs. 5.7%; p=0.002). The duration for slides prepared for examination was longer in ACD than in PCD (2.3 vs. 1.1 days; p<0.001), but this was still within the presumptive treatment period. Based on this we conclude that in the transition period to a decentralised health system, ACD for malaria parasites should be continued in a specified endemic area and therefore, efforts to retain the village malaria workers should be considered.


Subject(s)
Malaria/diagnosis , Population Surveillance/methods , Adolescent , Child , Child, Preschool , Female , Humans , Indonesia/epidemiology , Infant , Malaria/blood , Malaria/epidemiology , Male , Registries
9.
Microb Ecol ; 53(4): 591-9, 2007 May.
Article in English | MEDLINE | ID: mdl-17356948

ABSTRACT

Bacterial growth efficiency (BGE) is a key factor in understanding bacterial influence on carbon flow in aquatic ecosystems. We report intra-annual variability in BGE, and bacteria-mediated carbon flow in the tropical Mandovi and Zuari estuaries (southwest India) and the adjoining coastal waters (Arabian Sea). BGE ranged from 3% to 61% and showed clear temporal variability with significantly (ANOVA, p < 0.01) higher values in the estuaries (mean, 28 +/- 14%) than coastal waters (mean, 12 +/- 6%). The greater variability of BGE in the estuaries than coastal waters suggest some systematic response to nutrient composition and the variability of dissolved organic matter pools, as BGE was governed by bacterial secondary production (BP). Monsoonal rains and its accompanied changes brought significant variability in BGE and bacterial productivity/primary productivity (BP/PP) ratio when compared to nonmonsoon seasons in the estuaries and coastal waters. High BP/PP ratio (>1) together with high carbon flux through bacteria (>100% of primary productivity) in the estuarine and coastal waters suggests that bacterioplankton consumed dissolved organic carbon in excess of the amount produced in situ by phytoplankton of this region, which led to the mismatch between primary production of carbon and amount of carbon consumed by bacteria. Despite the two systems being subsidized by allochthonous inputs, the low BGE in the coastal waters may be attributable to the nature and time interval in the supply of allochthonous carbon.


Subject(s)
Bacteria/growth & development , Carbon/metabolism , Seasons , Tropical Climate , Water Microbiology , Bacteria/metabolism , Food Chain , Oceans and Seas , Rain , Rivers/microbiology , Water/chemistry
10.
Biometals ; 20(6): 821-8, 2007 Dec.
Article in English | MEDLINE | ID: mdl-17205210

ABSTRACT

The present study examines the metal and antibiotic resistant bacteria in ice and water from lakes east and west of the Indian base camp (Maitri) in Antarctica. The isolates from western and eastern lakes showed distinct geographical differences in properties like metal resistance and enzyme expression. This may be attributed to high organic loading in the lakes on the west of Maitri. However, there was no marked geopraphical distinction in antibiotic resistance between the lakes. Bacteria from the lakes on the eastern side showed resistance to three or more metals including mercury while, those from the western were resistant to only 1-2 metals excluding mercury. Multiple enzyme expression was more pronounced in the lakes on the western side. On the eastern side multiple metal resistance was encountered in bacterial isolates associated with fewer enzyme expressions suggesting a "trade-off". Thus these Antarctic isolates from the east trade their ability to express multiple enzymes for developing resistance to multiple metals including mercury.


Subject(s)
Bacteria/metabolism , Mercury/analysis , Mercury/pharmacology , Metals/chemistry , Water Microbiology , Antarctic Regions , Bacteria/enzymology , Colony Count, Microbial , Drug Resistance, Bacterial , Drug Resistance, Microbial , Drug Resistance, Multiple, Bacterial , Geography , Hydrogen-Ion Concentration , Microbial Sensitivity Tests , Water/chemistry
11.
J Med Entomol ; 43(3): 580-8, 2006 May.
Article in English | MEDLINE | ID: mdl-16739419

ABSTRACT

Entomological monitoring in four villages situated along an altitude transect in the Hai District of Northeastern Tanzania identified Anopheles arabiensis Patton as the principal vector of malaria and detected seasonal changes in vector behavior. Over a 13-mo sampling period, 10,557 mosquitoes were collected with CDC light traps, pyrethrum spray catches, and pit traps of which 5,969 (56.5%) wereAn. arabiensis, 762 (7.2%) wereAnopheles funestus Giles s.l., 3,578 (33.9%) were culicines, and 248 (2.3%) were nonvector anophelines. Vector densities declined rapidly with increasing altitude, demonstrating a 50% decrease in annual human biting rate for every 86-m rise in altitude. Light traps were found to be more efficient than spray catches for the collection of An. arabiensis. This observation was attributed to increased exophily of this species, most notably in the wet season, and is supported by seasonal changes in the human blood index and fed/gravid ratio. These results indicate that spray catches may underestimate the abundance of exophilic vectors such as An. arabiensis and that entomological monitoring may require more than one collection method, especially at low vector densities. The annual entomological inoculation rate (EIR) decreased sharply with increasing altitude, with large variation around the estimate at low vector densities. Increased transmission because of unpredictable short rains at low altitudes and spatial clustering of infective mosquitoes may contribute to elevated EIR estimates.


Subject(s)
Altitude , Anopheles , Insect Vectors , Malaria/transmission , Animals , Anopheles/classification , Anopheles/genetics , Blood , Humans , Insect Bites and Stings/epidemiology , Insect Control/methods , Malaria/epidemiology , Polymerase Chain Reaction , Population Density , Rural Population , Seasons , Tanzania/epidemiology
12.
Ecotoxicology ; 15(4): 379-84, 2006 May.
Article in English | MEDLINE | ID: mdl-16703457

ABSTRACT

In the wake of the findings that Antarctic krills concentrate heavy metals at ppm level, (Yamamoto et al. 1987), the Antarctic waters from the Indian side were examined for the incidence of metal and antibiotic-resistant bacteria during the austral summer (13th Indian Antarctic expedition) along the cruise track extending from 50 degrees S and 18 degrees E to 65 degrees S and 30 degrees E. The bacterial isolates from these waters showed varying degrees of resistance to antibiotics (Chloramphenicol, ampicillin, streptomycin, tetracycline and kanamycin) and metals (K(2)CrO(4), CdCl(2), ZnCl(2) and HgCl(2)) tested. Of the isolates screened, about 29% and 16% were resistant to 100 ppm of cadmium and chromium salt respectively. Tolerance to lower concentration (10 ppm) of mercury (Hg) was observed in 68% of the isolates. Depending on the antibiotics the isolates showed different percentage of resistance. Multiple drug and metal-resistance were observed. High incidence of resistance to both antibiotics and metals were common among the pigmented bacterial isolates. Increased resistance decreased the ability of bacteria to express enzymes. The results reiterate previous findings by other researchers that the waters of southern ocean may not be exempt from the spread of metal and antibiotic-resistance.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacteria/drug effects , Drug Resistance, Multiple, Bacterial , Metals, Heavy/pharmacology , Water Microbiology , Water Pollutants, Chemical/pharmacology , Antarctic Regions , Bacteria/enzymology , Bacteria/growth & development , Bacteria/isolation & purification , Gelatinases/analysis , Microbial Sensitivity Tests , Peptide Hydrolases/analysis , Seasons
13.
Trop Med Int Health ; 8(3): 211-8, 2003 Mar.
Article in English | MEDLINE | ID: mdl-12631310

ABSTRACT

Tuberculosis (TB) is a major public health problem in complex emergencies. Humanitarian agencies usually postpone the decision to offer TB treatment and opportunities to treat TB patients are often missed. This paper looks at the problem of tuberculosis treatment in these emergencies and questions whether treatment guidelines could be more flexible than international recommendations. A mathematical model is used to calculate the risks and benefits of different treatment scenarios with increasing default rates. Model outcomes are compared to a situation without treatment. An economic analysis further discusses the findings in a trade-off between the extra costs of treating relapses and failures and the savings in future treatment costs. In complex emergencies, if a TB programme could offer 4-month treatment for 75% of its patients, it could still be considered beneficial in terms of public health. In addition, the proportion of patients following at least 4 months of treatment can be used as an indicator to help evaluate the public health harm and benefit of the TB programme.


Subject(s)
Antitubercular Agents/therapeutic use , Relief Work , Tuberculosis, Pulmonary/drug therapy , Warfare , Drug Resistance, Bacterial , Emergencies , Health Care Costs , Humans , Models, Theoretical , Patient Compliance , Program Evaluation , Public Health/economics , Relief Work/economics , Risk Assessment/methods , Treatment Failure , Tuberculosis, Pulmonary/economics
14.
Microb Ecol ; 45(1): 88-96, 2003 Jan.
Article in English | MEDLINE | ID: mdl-12469247

ABSTRACT

Bacterial growth efficiency (BGE) is an index of organic carbon passing through bacteria in an aquatic system. BGE values of natural bacterioplankton assemblages were measured in tropical estuarine and adjacent coastal waters in Goa along the southwest coast of India. The BGE values for estuarine and coastal waters were 18 (+/-7.84%) and 11 (+/-4.19%), respectively. BGE in these waters were at the lower end of what is usually found in productive systems. This may be due to the high respiration rates. Further, it was observed that grazers also influenced BGE. As BGE was positively correlated with bacterial productivity, the observed variation in BGE was attributed to bacterial productivity. BGE was inversely related to C:N ratio, indicating a close coupling between the nature of the substrates and BGE. Being system-dependent, the variations in BGE at the two locations were dynamic and were regulated by the quality of the substrates. Therefore, a constant value for BGE would lead to error in carbon budgets in these waters.


Subject(s)
Bacteria/growth & development , Carbon/metabolism , Water Supply , Carbon/analysis , Ecosystem , Environmental Monitoring , India , Nitrogen/analysis , Nitrogen/metabolism , Tropical Climate
15.
Trop Med Int Health ; 6(7): 505-10, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11469942

ABSTRACT

We conducted a study of 1945 children and 2885 adults who presented with fever to a hospital outpatients clinic in an urban area of India order to develop and evaluate a clinical algorithm for the diagnosis of malaria. Only 139 (7%) children and 349 (12%) adults had microscopically confirmed malaria. None of the symptoms or signs elicited from the respondents were good predictors of clinical malaria. Simple scores were derived through combining clinical features which were associated with slide positivity or were judged by clinicians to be important. The best-performing algorithms were a score of 4 clinical features in children (sensitivity 60.0% and specificity 61.2%) and a score of 5 in adults (sensitivity 54.6% and specificity 57.5%). The clinical features differed and algorithm performances were poorer than in previous studies in highly endemic areas. The conclusion is that malaria diagnosis in areas of low endemicity requires microscopy to be accurate.


Subject(s)
Malaria/diagnosis , Adolescent , Adult , Algorithms , Child , Child, Preschool , Humans , India/epidemiology , Infant , Malaria/epidemiology , Malaria/physiopathology , Reproducibility of Results
16.
Int J Epidemiol ; 30(3): 509-14, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11416073

ABSTRACT

BACKGROUND: Verbal autopsy (VA) is an indirect method of ascertaining cause of death from information about symptoms and signs obtained from bereaved relatives. This method has been used in several settings to assess cause-specific mortality. However, cause-specific mortality estimates obtained by VA are susceptible to bias due to misclassification of causes of death. One way of overcoming this limitation of VA is to adjust the crude VA estimate of cause-specific mortality fractions (CSMF) using the sensitivity and specificity of the VA tool. This paper explores the application of sensitivity and specificity of VA data obtained from a hospital-based validation study for adjusting the effect of misclassification error in VA data obtained from a demographic surveillance system. METHOD: Data from a multi-centre validation study of 796 adult VA, conducted in Tanzania, Ethiopia and Ghana, were used to explore the effect of distribution of causes of death in the validation study population and the pattern of misclassification on the sensitivity and specificity of VA. VA estimates of CSMF for six causes (acute febrile illness, diarrhoeal diseases, TB/AIDS, cardiovascular disorders, direct maternal causes and injures) were obtained from a demographic surveillance system in Morogoro Rural District in Tanzania. These were adjusted for misclassification error by using sensitivity and specificity values of VA obtained from the validation study in a model proposed for correcting the effect of misclassification error in morbidity prevalence surveys. RESULTS: Sensitivity and specificity of VA differed between the three validation study sites depending on the distribution of causes of death. These differences were explained by variations in the level and pattern of misclassification between sites. When these estimates of sensitivity and specificity were applied to data from the demographic surveillance system with a comparable structure of causes of death the difference between crude and adjusted VA estimates of CSMF ranged from 3 to 83%. CONCLUSION: Estimates of sensitivity and specificity obtained from hospital-based validation studies must be used cautiously as a de facto 'gold standard' for adjusting the misclassification error in CSMF derived from VA. It is not possible to use sensitivity and specificity estimates derived from a location-specific validation study to adjust for misclassification in VA data from populations with substantially different patterns of cause-specific mortality.


Subject(s)
Autopsy/methods , Cause of Death , Classification/methods , Data Collection/methods , Ethiopia/epidemiology , Ghana/epidemiology , Humans , Population Surveillance , Reproducibility of Results , Sensitivity and Specificity , Tanzania/epidemiology
17.
Int J Epidemiol ; 30(3): 515-20, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11416074

ABSTRACT

BACKGROUND: Artificial neural networks (ANN) are gaining prominence as a method of classification in a wide range of disciplines. In this study ANN is applied to data from a verbal autopsy study as a means of classifying cause of death. METHODS: A simulated ANN was trained on a subset of verbal autopsy data, and the performance was tested on the remaining data. The performance of the ANN models were compared to two other classification methods (physician review and logistic regression) which have been tested on the same verbal autopsy data. RESULTS: Artificial neural network models were as accurate as or better than the other techniques in estimating the cause-specific mortality fraction (CSMF). They estimated the CSMF within 10% of true value in 8 out of 16 causes of death. Their sensitivity and specificity compared favourably with that of data-derived algorithms based on logistic regression models. CONCLUSIONS: Cross-validation is crucial in preventing the over-fitting of the ANN models to the training data. Artificial neural network models are a potentially useful technique for classifying causes of death from verbal autopsies. Large training data sets are needed to improve the performance of data-derived algorithms, in particular ANN models.


Subject(s)
Autopsy/methods , Cause of Death , Classification/methods , Neural Networks, Computer , Data Collection/methods , Ethiopia/epidemiology , Ghana/epidemiology , Humans , Logistic Models , Models, Statistical , Reproducibility of Results , Sensitivity and Specificity , Tanzania/epidemiology
19.
Appl Microbiol Biotechnol ; 57(3): 433-6, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11759698

ABSTRACT

The marine cyanobacteria Oscillatoria salina Biswas, Plectonema terebrans Bornet et Flahault and Aphanocapsa sp. degraded Bombay High crude oil when grown in artificial seawater nutrients as well as in plain natural seawater. Oil removal was measured by gravimetric and gas chromatographic methods. Around 45-55% of the total fractions of crude oil (containing 50% aliphatics, 31% waxes and bitumin, 14% aromatics and 5% polar compounds) were removed in the presence of these cultures within 10 days. Between 50% and 65% of pure hexadecane (model aliphatic compound) and 20% and 90% of aromatic compounds (anthracene and phenantherene) disappeared within 10 days. Mixed cultures of the three cyanobacterial species removed over 40% of the crude. Additionally, these cultures formed excellent cyanobacterial mats when grown in mixed cultures, and thus have the potential for use in mitigating oil pollution on seashores, either individually or in combination.


Subject(s)
Cyanobacteria/metabolism , Petroleum/metabolism , Water Pollutants, Chemical/metabolism , Water Purification/methods , Alkanes/metabolism , Anthracenes/metabolism , Chromatography, Gas , Cyanobacteria/growth & development , Phenanthrenes/metabolism
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