204 research outputs found
Energy Management of Dynamic Wireless Power Transfer Systems for Electric Vehicle Applications
Wireless power transfer is a method of transferring electric power from a transmitter to a receiver without requiring any physical connection between the two. Dynamic Wireless Power Transfer (DWPT) entails having the transmitters buried under the roadway and the receiver unit being installed on the Electric Vehicle (EV). In this method, EVs are charged while driving over the transmitters as they receive bursts of electric energy at the time of significant alignment between transmitters and receivers. Compared to the stationary charging method which involves parking the EV for long hours for a full charge, the dynamic charging method (i.e., DWPT) offers convenience as the vehicle gets charged while driving. It also facilitates extended driving range of EVs. Despite offering these advantages, DWPT causes a few significant issues. DWPT charging results in a transient power profile both at grid side and EV side, which not only hampers grid-side regulation but also affects EV-battery longevity. To address these two issues, both grid-side and EV-side energy management are needed to be employed to protect the grid and the vehicle from sudden exposure to harmful power transients. In this dissertation, the grid-side and EV-side energy management methods have been investigated. Firstly, a detection system to safely detect the vehicle on charging lane is proposed. This detection system is used to facilitate safe and efficient operation of DWPT chargers on EV roadways. Secondly, A novel DWPT system is proposed, which reduces the grid-side power transients with minimal additional hardware requirements. Finally, an EV-side energy management system is proposed which reduces the exposure of EV batteries to pulsating DPWT-power, thereby helping batteries to last longer
The Frequency of IgA Nephropathy at a Single Center in Pakistan
Objectives: To detect the prevalence of IgA nephropathy in Pakistani patients, as no significant published data from this part of the developing world is available in the international literature for reference.
Method: The study was conducted in a university hospital on 105 consecutive renal biopsy specimens. Direct immunofluorescence microscopy was performed using antibodies specific for the heavy chains of IgG, IgA, IgM, C3 and fibrinogen.
Results: Seventy-nine (79) cases were classified as glomerulopathies, out of which 10 cases (12.65%) were diagnosed as IgA nephropathy, among which one case was that of Henoch- Schonlein purpura. The age range was 6 to 65 years with median age of 25 years and male to female ratio was 1.5: 1. Nephrotic range proteinuria was seen in 40% of cases and 50% cases showed impaired renal function. The light microscopic examination revealed diffuse proliferative pattern in 3 cases out of which one case showed crescent formations. Focal-segmental glomerulosclerosis, minimum histologic lesion and advanced chronic glomerulonephritic patterns were observed in 2 cases each and in one case focal proliferative morphology was appreciated.
Conclusion: The frequency of IgA nephropathy among glomerular diseases was 12.65% in our study, which is somewhat higher when comparing the studies from North America, United Kingdom and Northwest Europe. However, it was significantly lower when comparing the studies from other parts of Asi
Community participatory learning and action cycle groups to reduce type 2 diabetes in Bangladesh (D:Clare trial): study protocol for a stepped-wedge cluster randomised controlled trial.
BACKGROUND: An estimated 463 million people globally have diabetes, with the prevalence growing in low-and middle-income settings, such as Bangladesh. Given the need for context-appropriate interventions to prevent type 2 diabetes mellitus (T2DM), the 'Diabetes: Community-led Awareness, Response and Evaluation' (D:Clare) trial will rigorously evaluate the replication and scale-up of a participatory learning and action (PLA) cycle intervention in Bangladesh, to inform policy on population-level T2DM prevention and control. METHODS: This is a stepped-wedge cluster randomised controlled trial, with integrated process and economic evaluations, conducted from March 2020 to September 2022. The trial will evaluate a community-based four-phase PLA cycle intervention focused on prevention and control of T2DM implemented over 18 months, against a control of usual care. Twelve clusters will be randomly allocated (1:1) to implement the intervention at project month 1 or 12. The intervention will be evaluated through three cross-sectional surveys at months 1, 12 and 24. The trial will be conducted in Alfadanga Upazila, Faridpur district, with an estimated population of 120,000. Clusters are defined as administrative geographical areas, with approximately equal populations. Each of the six unions in Alfadanga will be divided into two clusters, forming 12 clusters in total. Given the risk of inter-cluster contamination, evaluation surveys will exclude villages in border areas. Participants will be randomly sampled, independently for each survey, from a population census conducted in January 2020. The primary outcome is the combined prevalence of intermediate hyperglycaemia and T2DM, measured through fasting and 2-h post-glucose load blood tests. A total of 4680 participants provide 84% power to detect a 30% reduction in the primary outcome, assuming a baseline of 30% and an ICC of 0.07. The analysis will be by intention-to-treat, comparing intervention and control periods across all clusters, adjusting for geographical clustering. DISCUSSION: This study will provide further evidence of effectiveness for community-based PLA to prevent T2DM at scale in a rural Bangladesh setting. However, we encountered several challenges in applying the stepped-wedge design to our research context, with particular consideration given to balancing seasonality, timing and number of steps and estimation of partial versus full effect. TRIAL REGISTRATION: ISRCTN: ISRCTN42219712 . Registered on 31 October 2019
Participatory learning and action to address type 2 diabetes in rural Bangladesh: a qualitative process evaluation
BACKGROUND:
Diabetes is 7th largest cause of death worldwide, and prevalence is increasing rapidly in low-and middle-income countries. There is an urgent need to develop and test interventions to prevent and control diabetes and develop the theory about how such interventions can be effective. We conducted a participatory learning and action (PLA) intervention with community groups in rural Bangladesh which was evaluated through a cluster randomised controlled trial. There was a large reduction in the combined prevalence of type 2 diabetes and intermediate hyperglycaemia in the PLA group compared with the control group. We present findings from qualitative process evaluation research to explore how this intervention was effective. //
METHODS:
We conducted group interviews and focus group discussions using photovoice with purposively sampled group attenders and non-attenders, and intervention implementers. Data were collected before the trial analysis. We used inductive content analysis to generate theory from the data. //
RESULTS:
The intervention increased the health literacy of individuals and communities - developing their knowledge, capacity and self-confidence to enact healthy behaviours. Community, household and individual capacity increased through social support and social networks, which then created an enabling community context, further strengthening agency and enabling community action. This increased opportunities for healthy behaviour. Community actions addressed lack of awareness about diabetes, gendered barriers to physical activity and lack of access to blood glucose testing. The interaction between the individual, household, and community contexts amplified change, and yet there was limited engagement with macro level, or ‘state’, barriers to healthy behaviour. //
CONCLUSIONS:
The participatory approach enabled groups to analyse how context affected their ability to have healthy behaviours and participants engaged with issues as a community in the ways that they felt comfortable. We suggest measuring health literacy and social networks in future interventions and recommend specific capacity strengthening to develop public accountability mechanisms and health systems strengthening to complement community-based interventions
Generation of Genic Diversity among Streptococcus pneumoniae Strains via Horizontal Gene Transfer during a Chronic Polyclonal Pediatric Infection
Although there is tremendous interest in understanding the evolutionary roles of horizontal gene transfer (HGT) processes that occur during chronic polyclonal infections, to date there have been few studies that directly address this topic. We have characterized multiple HGT events that most likely occurred during polyclonal infection among nasopharyngeal strains of Streptococcus pneumoniae recovered from a child suffering from chronic upper respiratory and middle-ear infections. Whole genome sequencing and comparative genomics were performed on six isolates collected during symptomatic episodes over a period of seven months. From these comparisons we determined that five of the isolates were genetically highly similar and likely represented a dominant lineage. We analyzed all genic and allelic differences among all six isolates and found that all differences tended to occur within contiguous genomic blocks, suggestive of strain evolution by homologous recombination. From these analyses we identified three strains (two of which were recovered on two different occasions) that appear to have been derived sequentially, one from the next, each by multiple recombination events. We also identified a fourth strain that contains many of the genomic segments that differentiate the three highly related strains from one another, and have hypothesized that this fourth strain may have served as a donor multiple times in the evolution of the dominant strain line. The variations among the parent, daughter, and grand-daughter recombinant strains collectively cover greater than seven percent of the genome and are grouped into 23 chromosomal clusters. While capturing in vivo HGT, these data support the distributed genome hypothesis and suggest that a single competence event in pneumococci can result in the replacement of DNA at multiple non-adjacent loci
Polypyrrole-Fe[sub]2O[sub]3 nanocomposites with high dielectric constant : in situ chemical polymerisation
Novel nanocomposites of polypyrrole (PPy) dispersed with iron oxide (Fe2O3) particles have been synthesised by in-situ chemical oxidative polymerisation of pyrrole in the presence of ammonium persulfate (APS) as an oxidising agent. The concentration of Fe2O3 was varied between 10-50wt% of PPy. The simultaneous polymerisation of pyrrole and oxide addition led to the complete synthesis of
nanocomposites. A maximum dielectric constant of ~28500 was observed at 20wt% of Fe2O3. The nanocomposites were characterised by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD analysis confirmed the structure and crystallinity of the nanocomposites, and a strong interaction between PPy and the Fe2O3 nanoparticles was observed by FTIR technique. SEM and TEM images showed that Fe2O3 particles had been coated with PPy by establishing a network during the polymerisation process. The values of dielectric constant were obtained from capacitance measurements. The value of dielectric constant for nanocomposites with 20wt% of Fe2O3 was observed to be almost 12 times that of the pure PPy matrix.
The high value of dielectric constant indicated a high packing density of Fe2O3 particles in the PPy matrix.
These nanocomposites have potential applications in electronic or biomedical devices
Design and validation of a supragenome array for determination of the genomic content of Haemophilus influenzae isolates
Abstract
Background
Haemophilus influenzae colonizes the human nasopharynx as a commensal, and is etiologically associated with numerous opportunistic infections of the airway; it is also less commonly associated with invasive disease. Clinical isolates of H. influenzae display extensive genomic diversity and plasticity. The development of strategies to successfully prevent, diagnose and treat H. influenzae infections depends on tools to ascertain the gene content of individual isolates.
Results
We describe and validate a Haemophilus influenzae supragenome hybridization (SGH) array that can be used to characterize the full genic complement of any strain within the species, as well as strains from several highly related species. The array contains 31,307 probes that collectively cover essentially all alleles of the 2890 gene clusters identified from the whole genome sequencing of 24 clinical H. influenzae strains. The finite supragenome model predicts that these data include greater than 85% of all non-rare genes (where rare genes are defined as those present in less than 10% of sequenced strains). The veracity of the array was tested by comparing the whole genome sequences of eight strains with their hybridization data obtained using the supragenome array. The array predictions were correct and reproducible for ~ 98% of the gene content of all of the sequenced strains. This technology was then applied to an investigation of the gene content of 193 geographically and clinically diverse H. influenzae clinical strains. These strains came from multiple locations from five different continents and Papua New Guinea and include isolates from: the middle ears of persons with otitis media and otorrhea; lung aspirates and sputum samples from pneumonia and COPD patients, blood specimens from patients with sepsis; cerebrospinal fluid from patients with meningitis, as well as from pharyngeal specimens from healthy persons.
Conclusions
These analyses provided the most comprehensive and detailed genomic/phylogenetic look at this species to date, and identified a subset of highly divergent strains that form a separate lineage within the species. This array provides a cost-effective and high-throughput tool to determine the gene content of any H. influenzae isolate or lineage. Furthermore, the method for probe selection can be applied to any species, given a group of available whole genome sequences.http://deepblue.lib.umich.edu/bitstream/2027.42/112375/1/12864_2012_Article_5193.pd
Distribution of diabetes, hypertension and non-communicable disease risk factors among adults in rural Bangladesh: a cross-sectional survey
Background: Non-communicable diseases (NCDs) are increasing in low-income settings. We conducted a survey of risk factors, blood pressure and blood glucose in rural Bangladesh and assessed variations by age, sex and wealth. Methods: We surveyed a random sample of 12 280 adults aged >30 years in 96 villages in rural Bangladesh. Fieldworkers measured blood glucose and conducted an insulin tolerance test with a repeat blood test 120 min post glucose ingestion. Blood pressure, anthropometric, socioeconomic, lifestyle and behavioural risk factors data were also collected. Data were analysed to describe the prevalence of diabetes, intermediate hyperglycaemia, hypertension and NCD risk factors by age, sex and wealth. Results: Women had higher levels of overweight or obesity and lower levels of physical activity and fruit and vegetable consumption than men; 63% of men used tobacco compared with 41.3% of women. Overweight or obesity and abdominal obesity (waist to hip ratio) increased with socioeconomic status (least poor vs most poor: OR (95% CI) 3.21 (2.51 to 4.11) for men and 2.83 (2.28 to 3.52) for women). Tobacco use, passive smoke exposure and salt consumption fell with increasing socioeconomic status in both sexes. Clustering of risk factors showed more than 70% of men and women reported at least three risk factors. Women in the least poor group were 33% more likely to have three or more risk factors compared with women in the most poor group (1.33 (95% CI 1.17 to 1.58)). The combined prevalence of impaired fasting glucose, impaired glucose tolerance and diabetes was 26.1% among men and 34.9% among women, and increased with age. The prevalence of prehypertension and hypertension was 30.7% and 15.9% among men and 27.2% and 22.5% among women, with similar rising prevalence with age. Conclusion: NCD risk factors, hyperglycaemia and raised blood pressure are an immediate health threat in rural Bangladesh. Initiatives to improve detection, treatment and prevention strategies are needed
Differences in genotype and virulence among four multidrug-resistant <i>Streptococcus pneumoniae</i> isolates belonging to the PMEN1 clone
We report on the comparative genomics and characterization of the virulence phenotypes of four <i>S. pneumoniae</i> strains that belong to the multidrug resistant clone PMEN1 (Spain<sup>23F</sup> ST81). Strains SV35-T23 and SV36-T3 were recovered in 1996 from the nasopharynx of patients at an AIDS hospice in New York. Strain SV36-T3 expressed capsule type 3 which is unusual for this clone and represents the product of an in vivo capsular switch event. A third PMEN1 isolate - PN4595-T23 - was recovered in 1996 from the nasopharynx of a child attending day care in Portugal, and a fourth strain - ATCC700669 - was originally isolated from a patient with pneumococcal disease in Spain in 1984. We compared the genomes among four PMEN1 strains and 47 previously sequenced pneumococcal isolates for gene possession differences and allelic variations within core genes. In contrast to the 47 strains - representing a variety of clonal types - the four PMEN1 strains grouped closely together, demonstrating high genomic conservation within this lineage relative to the rest of the species. In the four PMEN1 strains allelic and gene possession differences were clustered into 18 genomic regions including the capsule, the blp bacteriocins, erythromycin resistance, the MM1-2008 prophage and multiple cell wall anchored proteins. In spite of their genomic similarity, the high resolution chinchilla model was able to detect variations in virulence properties of the PMEN1 strains highlighting how small genic or allelic variation can lead to significant changes in pathogenicity and making this set of strains ideal for the identification of novel virulence determinant
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