1,133 research outputs found

    Direct Tuning Phase-Shift Angle In Dab Dc-Dc Converter Using Moth Flame Optimization (Mfo) Algorithm

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    The world is currently experiencing a global energy crisis due to the limited natural energy resources that are used to power industrial society, where as demand increases, the available resources are being depleted. The evolution of renewable energy able to overcome this energy crisis. DC-DC converter is one of the vital components used in the renewable energy system as power conversion tools. However, most of the existing DCDC converter has unidirectional power flow which have limitations in term of energy management efficiency due to one way power flow. Besides, the non-isolated bidirectional power flow has restrictions in high voltage conversion gain, safety and power quality. Therefore, a 100 kW isolated bidirectional Dual Active Bridge (DAB) DC-DC converter with single phase shift (SPS) modulation have been developed using MATLAB/Simulink software. Apart from that, the tuning method of phase-shift angle variable in DAB plays the important role to produce the desired output. Since the conventional tuning has a couple of downsides, mainly related to the time-consuming and inconsistence accuracy, the auto-tuning phase shift angle using Moth Flame Optimization (MFO) algorithm in DAB is proposed in this project. The proposed method is tested in terms of accuracy, efficiency and convergence speed for various load system which is 100 kW, 75 kW and 50 kW under various reference voltage. The results from the research depicts that the DAB system with 100 kW, 75kW and 50 kW respectively has the best convergence speed, highest efficiency and highest accuracy with lowest ripple. With aforementioned results, the MFO algorithm have well-functioning in DAB system

    Comparative transcriptomics of multidrug-resistant Acinetobacter baumannii in response to antibiotic treatments

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    Abstract Multidrug-resistant Acinetobacter baumannii, a major hospital-acquired pathogen, is a serious health threat and poses a great challenge to healthcare providers. Although there have been many genomic studies on the evolution and antibiotic resistance of this species, there have been very limited transcriptome studies on its responses to antibiotics. We conducted a comparative transcriptomic study on 12 strains with different growth rates and antibiotic resistance profiles, including 3 fast-growing pan-drug-resistant strains, under separate treatment with 3 antibiotics, namely amikacin, imipenem, and meropenem. We performed deep sequencing using a strand-specific RNA-sequencing protocol, and used de novo transcriptome assembly to analyze gene expression in the form of polycistronic transcripts. Our results indicated that genes associated with transposable elements generally showed higher levels of expression under antibiotic-treated conditions, and many of these transposon-associated genes have previously been linked to drug resistance. Using co-expressed transposon genes as markers, we further identified and experimentally validated two novel genes of which overexpression conferred significant increases in amikacin resistance. To the best of our knowledge, this study represents the first comparative transcriptomic analysis of multidrug-resistant A. baumannii under different antibiotic treatments, and revealed a new relationship between transposons and antibiotic resistance

    A simple, rapid typing method for Streptococcus agalactiae based on ribosomal subunit proteins by MALDI-TOF MS

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    Streptococcus agalactiae (Group B Streptococcus, GBS), is a frequent human colonizer and a leading cause of neonatal meningitis as well as an emerging pathogen in non-pregnant adults. GBS possesses a broad animal host spectrum, and recent studies proved atypical GBS genotypes can cause human invasive diseases through animal sources as food-borne zoonotic infections. We applied a MALDI-TOF MS typing method, based on molecular weight variations of predefined 28 ribosomal subunit proteins (rsp) to classify GBS strains of varying serotypes into major phylogenetic lineages. A total of 249 GBS isolates of representative and varying capsular serotypes from patients and animal food sources (fish and pig) collected during 2016-2018 in Hong Kong were analysed. Over 84% (143/171) noninvasive carriage GBS strains from patients were readily typed into 5 globally dominant rsp-profiles. Among GBS strains from food animals, over 90% (57/63) of fish and 13% (2/15) of pig GBS matched with existing rsp-profiles, while the remainder were classified into two novel rsp-profiles and we failed to assign a fish strain into any cluster. MALDI-TOF MS allowed for high-throughput screening and simultaneous detection of novel, so far not well described GBS genotypes. The method shown here is rapid, simple, readily transferable and adapted for use in a diagnostic microbiology laboratory with potential for the surveillance of emerging GBS genotypes with zoonotic potential

    Patients’ perceptions and experiences of living with a surgical wound healing by secondary intention : a qualitative study

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    Background: Most surgical wounds heal by primary intention, that is to say, the edges of the wound are brought together with sutures, staples, adhesive glue or clips. However, some wounds may be left open to heal (if there is a risk of infection, or if there has been significant tissue loss), and are known as ‘surgical wounds healing by secondary intention’. They are estimated to comprise approximately 28% of all surgical wounds and are frequently complex to manage. However, they are under researched and little is known of their impact on patients’ lives. Objectives: To explore patients’ views and experiences of living with a surgical wound healing by secondary intention. Design: A qualitative, descriptive approach. Settings: Participants were recruited from acute and community nursing services in two locations in the North of England characterised by high levels of deprivation and diverse populations. Participants: Participants were aged 18 years or older and had at least one surgical wound healing by secondary intention, which was slow to heal. Purposeful sampling was used to include patients of different gender, age, wound duration and type of surgery (general, vascular and orthopaedic). Twenty people were interviewed between January and July 2012. 2 Methods: Semi-structured interviews were conducted, guided by use of a topic guide developed with input from patient advisors. Data were thematically analysed using steps integral to the ‘Framework’ approach to analysis, including familiarisation with data; development of a coding scheme; coding, charting and cross comparison of data; interpretation of identified themes. Findings: Alarm, shock and disbelief were frequently expressed initial reactions, particularly to “unexpected” surgical wounds healing by secondary intention. Wound associated factors almost universally had a profound negative impact on daily life, physical and psychosocial functioning, and wellbeing. Feelings of frustration, powerlessness and guilt were common and debilitating. Patients’ hopes for healing were often unrealistic, posing challenges for the clinicians caring for them. Participants expressed dissatisfaction with a perceived lack of continuity and consistency of care in relation to wound management. Conclusions: Surgical wounds healing by secondary intention can have a devastating effect on patients, both physical and psychosocial. Repercussions for patients’ family members can also be extremely detrimental, including financial pressures. Health care professionals involved in the care of patients with these wounds face multiple, complex challenges, compounded by the limited evidence base regarding cost-effectiveness of different treatment regimens for these types of wounds

    Recognizing Intimate Partner Violence in Primary Care: Western Cape, South Africa

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    Introduction: Interpersonal violence in South Africa is the second highest contributor to the burden of disease after HIV/ AIDS and 62 % is estimated to be from intimate partner violence (IPV). This study aimed to evaluate how women experiencing IPV present in primary care, how often IPV is recognized by health care practitioners and what other diagnoses are made. Methods: At two urban and three rural community health centres, health practitioners were trained to screen all women fo

    The state of the Martian climate

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    60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

    Obstructive Sleep Apnea Alters Sleep Stage Transition Dynamics

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    Enhanced characterization of sleep architecture, compared with routine polysomnographic metrics such as stage percentages and sleep efficiency, may improve the predictive phenotyping of fragmented sleep. One approach involves using stage transition analysis to characterize sleep continuity.We analyzed hypnograms from Sleep Heart Health Study (SHHS) participants using the following stage designations: wake after sleep onset (WASO), non-rapid eye movement (NREM) sleep, and REM sleep. We show that individual patient hypnograms contain insufficient number of bouts to adequately describe the transition kinetics, necessitating pooling of data. We compared a control group of individuals free of medications, obstructive sleep apnea (OSA), medical co-morbidities, or sleepiness (n = 374) with mild (n = 496) or severe OSA (n = 338). WASO, REM sleep, and NREM sleep bout durations exhibited multi-exponential temporal dynamics. The presence of OSA accelerated the "decay" rate of NREM and REM sleep bouts, resulting in instability manifesting as shorter bouts and increased number of stage transitions. For WASO bouts, previously attributed to a power law process, a multi-exponential decay described the data well. Simulations demonstrated that a multi-exponential process can mimic a power law distribution.OSA alters sleep architecture dynamics by decreasing the temporal stability of NREM and REM sleep bouts. Multi-exponential fitting is superior to routine mono-exponential fitting, and may thus provide improved predictive metrics of sleep continuity. However, because a single night of sleep contains insufficient transitions to characterize these dynamics, extended monitoring of sleep, probably at home, would be necessary for individualized clinical application

    Informing etiologic research priorities for squamous cell esophageal cancer in Africa: a review of setting-specific exposures to known and putative risk factors

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    Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers in most Eastern and Southern African countries, but its etiology has been understudied to date. To inform its research agenda, we undertook a review to identify, of the ESCC risk factors which have been established or strongly suggested worldwide, those with a high prevalence or high exposure levels in any ESCC-affected African setting and the sources thereof. We found that for almost all ESCC risk factors known to date, including tobacco, alcohol, hot beverage consumption, nitrosamines and both inhaled and ingested PAHs, there is evidence of population groups with raised exposures, the sources of which vary greatly between cultures across the ESCC corridor. Research encompassing these risk factors is warranted and is likely to identify primary prevention strategies
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