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Search Results: 1 - 10 of 1441 matches for " Christiane Dolecek "
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Multiplierless Wideband and Narrowband CIC Compensator for SDR Application  [PDF]
Gordana Jovanovic Dolecek
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2017, DOI: 10.4236/ijcns.2017.108B003
Abstract:
This paper presents multiplierless CIC compensator for software-defined radio (SDR) application. The compensator is composed of two simple filters with sinewave form of magnitude responses. The parameters of the design are the sinewave amplitudes expressed as powers-of-two and estimated in a way to fulfill the absolute value of the maximum passband deviation of 0.25 dB and 0.05 dB, for the wideband and narrowband compensations, respectively. The proposed compensator requires maximum nine adders. The comparisons with the methods proposed in literature show the benefits of the proposed compensator.
Traction Converting Substation from Viewpoint of Feeding Interlocking Plant at Czech Railwayes
Radovan Dolecek
Advances in Electrical and Electronic Engineering , 2004,
Abstract: This paper presents analyses current and voltage harmonic in traction converting substation 3 kV. It researches their rise and influence to three-phase cable line 6 kV, 50 Hz that is used for feeding interlocking plant. Processing of this task is arisen from requirement practice for line Pě ky - Po í any - Rostoklaty where happened to adverse ratio in particular transmission line of feeding system. It is meant especially about backward influence traction substation rectifier Pe ky to three - phase cable line 6 kV, 50 Hz. At the determinate lenght of the cable line, when resonace frequency of circuit transformer 22 kV/6 kV and the cable line 6 kV, 50 Hz is approached frequency 550 Hz and 650 Hz (i.e. 11 and 13 harmonic) are happened to socalled "annulations input reactance of this circuit". That is caused by the leakage of current resonace frequency from traction converting substation to cable line. That proceduces additional losses and deformation waveform of voltage too. This deformation can be reflected on how interlocking plant is working.
An Open Randomized Comparison of Gatifloxacin versus Cefixime for the Treatment of Uncomplicated Enteric Fever
Anil Pandit, Amit Arjyal, Jeremy N. Day, Buddhi Paudyal, Sabina Dangol, Mark D. Zimmerman, Bharat Yadav, Kasia Stepniewska, James I. Campbell, Christiane Dolecek, Jeremy J. Farrar, Buddha Basnyat
PLOS ONE , 2007, DOI: 10.1371/journal.pone.0000542
Abstract: Objective To assess the efficacy of gatifloxacin versus cefixime in the treatment of uncomplicated culture positive enteric fever. Design A randomized, open-label, active control trial with two parallel arms. Setting Emergency Room and Outpatient Clinics in Patan Hospital, Lagankhel, Lalitpur, Nepal. Participants Patients with clinically diagnosed uncomplicated enteric fever meeting the inclusion criteria. Interventions Patients were allocated to receive one of two drugs, Gatifloxacin or Cefixime. The dosages used were Gatifloxacin 10 mg/kg, given once daily for 7 days, or Cefixime 20 mg/kg/day given in two divided doses for 7 days. Outcome Measures The primary outcome measure was fever clearance time. The secondary outcome measure was overall treatment failure (acute treatment failure and relapse). Results Randomization was carried out in 390 patients before enrollment was suspended on the advice of the independent data safety monitoring board due to significant differences in both primary and secondary outcome measures in the two arms and the attainment of a priori defined endpoints. Median (95% confidence interval) fever clearance times were 92 hours (84–114 hours) for gatifloxacin recipients and 138 hours (105–164 hours) for cefixime-treated patients (Hazard Ratio[95%CI] = 2.171 [1.545–3.051], p<0.0001). 19 out of 70 (27%) patients who completed the 7 day trial had acute clinical failure in the cefixime group as compared to 1 out of 88 patients (1%) in gatifloxacin group(Odds Ratio [95%CI] = 0.031 [0.004 – 0.237], p<0.001). Overall treatment failure patients (relapsed patients plus acute treatment failure patients plus death) numbered 29. They were determined to be (95% confidence interval) 37.6 % (27.14%–50.2%) in the cefixime group and 3.5% (2.2%–11.5%) in the gatifloxacin group (HR[95%CI] = 0.084 [0.025–0.280], p<0.0001). There was one death in the cefixime group. Conclusions Based on this study, gatifloxacin is a better treatment for uncomplicated enteric fever as compared to cefixime. Trial Registration Current Controlled Trials ISRCTN75784880
Genetic Variability of Plasmodium malariae dihydropteroate synthase (dhps) in Four Asian Countries
Naowarat Tanomsing, Mayfong Mayxay, Paul N. Newton, Francois Nosten, Christiane Dolecek, Tran Tinh Hien, Nicholas J. White, Nicholas P. J. Day, Arjen M. Dondorp, Mallika Imwong
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0093942
Abstract: The dihydropteroate synthase (dhps) genes of 44 P. malariae strains from four Asian countries were isolated. Only a limited number of polymorphisms were observed. Comparison with homologous mutations in other Plasmodium species showed that these polymorphisms are unlikely to be associated with sulfadoxine resistance.
EMC Increasing of PWM Rectifier in Comparison with Classical Rectifier
J. Lettl,R. Dolecek
Radioengineering , 2008,
Abstract: Pulse width modulated rectifier is a very popular topic nowadays. The modern industrial production demands continuous and lossless conversion of electrical energy parameters. This need leads to wide spread of power semiconductor converters. The rapid development in power electronics and microprocessor technology enables to apply sophisticated control methods that eliminate negative side effects of the power converters on the supply network. The phase controlled thyristor rectifiers overload the supply network with higher harmonics and reactive power consumption. That is why the PWM rectifier is being examined. In comparison with the phase controlled rectifier it can be controlled to consume nearly sinusoidal current with power factor equal to unity. Another advantage is its capability of energy recuperation. The PWM rectifier can assert itself for its good behavior in many applications, for example as an input rectifier in indirect frequency converter, or in traction. Traction vehicles equipped with PWM rectifier do not consume reactive power, do not load the supply network with higher harmonics, and the recuperation is possible. The paper deals with the PWM rectifier functional model realization and examination. Electromagnetic compatibility of PWM rectifier and classical phase controlled rectifier is compared on the basis of the input current harmonic analysis.
Transient Effects at Power-Supply System of the Czech Railways from EMC Viewpoint
R. Dolecek,K. Hlava
Radioengineering , 2007,
Abstract: The paper deals with the behavior of the traction power-supply system 25 kV, 50 Hz at the Czech Railways. Electrical conditions on a contact line affect electrical conditions in a feeding station. This relation represents galvanic coupling from EMC viewpoint. Explanation of transient effects during short-circuits at the contact line can be considered as the main problem. These effects can arise during a failure in a traction circuit. Therefore, the attention is turned to an adjustment protection design of the traction circuit. Simulation diagrams were created. The design can be utilizable for a feeding station with Filter-Compensation Equipment, which is designed for the EMI reduction.
The sensitivity of real-time PCR amplification targeting invasive Salmonella serovars in biological specimens
Tran Nga, Abhilasha Karkey, Sabina Dongol, Hang Thuy, Sarah Dunstan, Kathryn Holt, Le Tu, James I Campbell, Tran Chau, Nguyen Chau, Amit Arjyal, Samir Koirala, Buddha Basnyat, Christiane Dolecek, Jeremy Farrar, Stephen Baker
BMC Infectious Diseases , 2010, DOI: 10.1186/1471-2334-10-125
Abstract: We developed and optimised a novel multiplex three colour real-time PCR assay to detect specific target sequences in the genomes of Salmonella serovars Typhi and Paratyphi A. We performed the assay on DNA extracted from blood and bone marrow samples from culture positive and negative enteric fever patients.The assay was validated and demonstrated a high level of specificity and reproducibility under experimental conditions. All bone marrow samples tested positive for Salmonella, however, the sensitivity on blood samples was limited. The assay demonstrated an overall specificity of 100% (75/75) and sensitivity of 53.9% (69/128) on all biological samples. We then tested the PCR detection limit by performing bacterial counts after inoculation into blood culture bottles.Our findings corroborate previous clinical findings, whereby the bacterial load of S. Typhi in peripheral blood is low, often below detection by culture and, consequently, below detection by PCR. Whilst the assay may be utilised for environmental sampling or on differing biological samples, our data suggest that PCR performed directly on blood samples may be an unsuitable methodology and a potentially unachievable target for the routine diagnosis of enteric fever.The detection of invasive Salmonella serovars such as Salmonella Typhi (S. Typhi) and Salmonella Paratyphi A (S. Paratyphi A) remains a challenging problem. Depending on the location, various different tests and clinical criteria are used to distinguish febrile disease of differing aetiology, many of which still may remain unsatisfactorily identified. In resource poor settings with a high disease burden, enteric fever is largely distinguished on the basis of clinical symptoms and syndromes [1-4]. Yet, clinical symptoms are not the most reliable assessment for enteric fever, as other conditions, such as typhus, malaria and leptospirosis have similar clinical manifestations and are also common in places such as Nepal [5,6].The current WHO guidelin
A Rapid, Multiplexed, High-Throughput Flow-Through Membrane Immunoassay: A Convenient Alternative to ELISA
Sujatha Ramachandran,Mitra Singhal,Katherine G. McKenzie,Jennifer L. Osborn,Amit Arjyal,Sabina Dongol,Stephen G. Baker,Buddha Basnyat,Jeremy Farrar,Christiane Dolecek,Gonzalo J. Domingo,Paul Yager,Barry Lutz
Diagnostics , 2013, DOI: 10.3390/diagnostics3020244
Abstract: This paper describes a rapid, high-throughput flow-through membrane immunoassay (FMIA) platform. A nitrocellulose membrane was spotted in an array format with multiple capture and control reagents for each sample detection area, and assay steps were carried out by sequential aspiration of sample and reagents through each detection area using a 96-well vacuum manifold. The FMIA provides an alternate assay format with several advantages over ELISA. The high surface area of the membrane permits high label concentration using gold labels, and the small pores and vacuum control provide rapid diffusion to reduce total assay time to ~30 min. All reagents used in the FMIA are compatible with dry storage without refrigeration. The results appear as colored spots on the membrane that can be quantified using a flatbed scanner. We demonstrate the platform for detection of IgM specific to lipopolysaccharides (LPS) derived from Salmonella Typhi. The FMIA format provides analytical results comparable to ELISA in less time, provides integrated assay controls, and allows compensation for specimen-to-specimen variability in background, which is a particular challenge for IgM assays.
Differential Epidemiology of Salmonella Typhi and Paratyphi A in Kathmandu, Nepal: A Matched Case Control Investigation in a Highly Endemic Enteric Fever Setting
Abhilasha Karkey equal contributor,Corinne N. Thompson equal contributor,Nga Tran Vu Thieu,Sabina Dongol,Tu Le Thi Phuong,Phat Voong Vinh,Amit Arjyal,Laura B. Martin,Simona Rondini,Jeremy J. Farrar,Christiane Dolecek,Buddha Basnyat,Stephen Baker
PLOS Neglected Tropical Diseases , 2013, DOI: 10.1371/journal.pntd.0002391
Abstract: Background Enteric fever, a systemic infection caused by the bacteria Salmonella Typhi and Salmonella Paratyphi A, is endemic in Kathmandu, Nepal. Previous work identified proximity to poor quality water sources as a community-level risk for infection. Here, we sought to examine individual-level risk factors related to hygiene and sanitation to improve our understanding of the epidemiology of enteric fever in this setting. Methodology and principal findings A matched case-control analysis was performed through enrollment of 103 blood culture positive enteric fever patients and 294 afebrile community-based age and gender-matched controls. A detailed questionnaire was administered to both cases and controls and the association between enteric fever infection and potential exposures were examined through conditional logistic regression. Several behavioral practices were identified as protective against infection with enteric fever, including water storage and hygienic habits. Additionally, we found that exposures related to poor water and socioeconomic status are more influential in the risk of infection with S. Typhi, whereas food consumption habits and migration play more of a role in risk of S. Paratyphi A infection. Conclusions and significance Our work suggests that S. Typhi and S. Paratyphi A follow different routes of infection in this highly endemic setting and that sustained exposure to both serovars probably leads to the development of passive immunity. In the absence of a polyvalent vaccine against S. Typhi and S. Paratyphi A, we advocate better systems for water treatment and storage, improvements in the quality of street food, and vaccination with currently available S. Typhi vaccines.
Temporal Fluctuation of Multidrug Resistant Salmonella Typhi Haplotypes in the Mekong River Delta Region of Vietnam
Kathryn E. Holt equal contributor ,Christiane Dolecek equal contributor,Tran Thuy Chau,Pham Thanh Duy,Tran Thi Phi La,Nguyen Van Minh Hoang,Tran Vu Thieu Nga,James I. Campbell,Bui Huu Manh,Nguyen Van Vinh Chau,Tran Tinh Hien,Jeremy Farrar,Gordon Dougan,Stephen Baker
PLOS Neglected Tropical Diseases , 2011, DOI: 10.1371/journal.pntd.0000929
Abstract: Background Typhoid fever remains a public health problem in Vietnam, with a significant burden in the Mekong River delta region. Typhoid fever is caused by the bacterial pathogen Salmonella enterica serovar Typhi (S. Typhi), which is frequently multidrug resistant with reduced susceptibility to fluoroquinolone-based drugs, the first choice for the treatment of typhoid fever. We used a GoldenGate (Illumina) assay to type 1,500 single nucleotide polymorphisms (SNPs) and analyse the genetic variation of S. Typhi isolated from 267 typhoid fever patients in the Mekong delta region participating in a randomized trial conducted between 2004 and 2005. Principal Findings The population of S. Typhi circulating during the study was highly clonal, with 91% of isolates belonging to a single clonal complex of the S. Typhi H58 haplogroup. The patterns of disease were consistent with the presence of an endemic haplotype H58-C and a localised outbreak of S. Typhi haplotype H58-E2 in 2004. H58-E2-associated typhoid fever cases exhibited evidence of significant geo-spatial clustering along the S?ng H u branch of the Mekong River. Multidrug resistance was common in the established clone H58-C but not in the outbreak clone H58-E2, however all H58 S. Typhi were nalidixic acid resistant and carried a Ser83Phe amino acid substitution in the gyrA gene. Significance The H58 haplogroup dominates S. Typhi populations in other endemic areas, but the population described here was more homogeneous than previously examined populations, and the dominant clonal complex (H58-C, -E1, -E2) observed in this study has not been detected outside Vietnam. IncHI1 plasmid-bearing S. Typhi H58-C was endemic during the study period whilst H58-E2, which rarely carried the plasmid, was only transient, suggesting a selective advantage for the plasmid. These data add insight into the outbreak dynamics and local molecular epidemiology of S. Typhi in southern Vietnam.
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