Modelling and experimental investigation of carangiform locomotion for control

We propose a model for planar carangiform swimming based on conservative equations for the interaction of a rigid body and an incompressible fluid. We account for the generation of thrust due to vortex shedding through controlled coupling terms. We investigate the correct form of this coupling experimentally with a robotic propulsor, comparing its observed behavior to that predicted by unsteady hydrodynamics. Our analysis of thrust generation by an oscillating hydrofoil allows us to characterize and evaluate certain families of gaits. Our final swimming model takes the form of a control-affine nonlinear system

SUMMARY OF THE WORKSHOP ON PERINATAL AND POSTNATAL DEFECTS AND NEUROLOGIC ABNORMALITIES FROM CHEMICAL EXPOSURES

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73502/1/j.1749-6632.1979.tb56627.x.pd

PFGE, Lior serotype, and antimicrobial resistance patterns among Campylobacter jejuni isolated from travelers and US military personnel with acute diarrhea in Thailand, 1998-2003

<p>Abstract</p> <p>Background</p> <p><it>Campylobacter jejuni </it>is a major cause of gastroenteritis worldwide. In Thailand, several strains of <it>C. jejuni </it>have been isolated and identified as major diarrheal pathogens among adult travelers. To study the epidemiology of <it>C. jejuni </it>in adult travelers and U.S. military personnel with acute diarrhea in Thailand from 1998-2003, strains of <it>C. jejuni </it>were isolated and phenotypically identified, serotyped, tested for antimicrobial susceptibility, and characterized using pulsed-field gel electrophoresis (PFGE).</p> <p>Results</p> <p>A total of 312 <it>C. jejuni </it>isolates were obtained from travelers (n = 46) and U.S. military personnel (n = 266) in Thailand who were experiencing acute diarrhea. Nalidixic acid and ciprofloxacin resistance was observed in 94.9% and 93.0% of the isolates, respectively. From 2001-2003, resistance to tetracycline (81.9%), trimethoprim-sulfamethoxazole (57.9%), ampicillin (28.9%), kanamycin (5.9%), sulfisoxazole (3.9%), neomycin (2.0%), and streptomycin (0.7%) was observed. Combined PFGE analysis showed considerable genetic diversity among the <it>C. jejuni </it>isolates; however, four PFGE clusters included isolates from the major Lior serotypes (HL: 36, HL: 11, HL: 5, and HL: 28). The PFGE analysis linked individual <it>C. jejuni </it>clones that were obtained at U.S. military exercises with specific antimicrobial resistance patterns.</p> <p>Conclusions</p> <p>In summary, most human <it>C. jejuni </it>isolates from Thailand were multi-resistant to quinolones and tetracycline. PFGE detected spatial and temporal <it>C. jejuni </it>clonality responsible for the common sources of <it>Campylobacter </it>gastroenteritis.</p

CTL epitope distribution patterns in the Gag and Nef proteins of HIV-1 from subtype A infected subjects in Kenya: Use of multiple peptide sets increases the detectable breadth of the CTL response

BACKGROUND: Subtype A is a major strain in the HIV-1 pandemic in eastern Europe, central Asia and in certain regions of east Africa, notably in rural Kenya. While considerable effort has been focused upon mapping and defining immunodominant CTL epitopes in HIV-1 subtype B and subtype C infections, few epitope mapping studies have focused upon subtype A. RESULTS: We have used the IFN-γ ELIspot assay and overlapping peptide pools to show that the pattern of CTL recognition of the Gag and Nef proteins in subtype A infection is similar to that seen in subtypes B and C. The p17 and p24 proteins of Gag and the central conserved region of Nef were targeted by CTL from HIV-1-infected Kenyans. Several epitope/HLA associations commonly seen in subtype B and C infection were also observed in subtype A infections. Notably, an immunodominant HLA-C restricted epitope (Gag 296–304; YL9) was observed, with 8/9 HLA-C(W)0304 subjects responding to this epitope. Screening the cohort with peptide sets representing subtypes A, C and D (the three most prevalent HIV-1 subtypes in east Africa), revealed that peptide sets based upon an homologous subtype (either isolate or consensus) only marginally improved the capacity to detect CTL responses. While the different peptide sets detected a similar number of responses (particularly in the Gag protein), each set was capable of detecting unique responses not identified with the other peptide sets. CONCLUSION: Hence, screening with multiple peptide sets representing different sequences, and by extension different epitope variants, can increase the detectable breadth of the HIV-1-specific CTL response. Interpreting the true extent of cross-reactivity may be hampered by the use of 15-mer peptides at a single concentration and a lack of knowledge of the sequence that primed any given CTL response. Therefore, reagent choice and knowledge of the exact sequences that prime CTL responses will be important factors in experimentally defining cross-reactive CTL responses and their role in HIV-1 disease pathogenesis and validating vaccines aimed at generating broadly cross-reactive CTL responses

First multi-locus sequence typing scheme for Arcobacter spp.

<p>Abstract</p> <p>Background</p> <p><it>Arcobacter </it>spp. are a common contaminant of food and water, and some species, primarily <it>A. butzleri </it>and <it>A. cryaerophilus</it>, have been isolated increasingly from human diarrheal stool samples. Here, we describe the first <it>Arcobacter </it>multilocus sequence typing (MLST) method for <it>A. butzleri</it>, <it>A. cryaerophilus</it>, <it>A. skirrowii, A. cibarius </it>and <it>A. thereius</it>.</p> <p>Results</p> <p>A sample set of 374 arcobacters, including 275 <it>A. butzleri</it>, 72 <it>A. cryaerophilus</it>, 15 <it>A. skirrowii </it>and 8 <it>A. cibarius </it>isolates from a wide variety of geographic locations and sources, was typed in this study. Additionally, this sample set contained four strains representing a new <it>Arcobacter </it>species, <it>A. thereius</it>. The seven loci used in the four-species <it>Arcobacter </it>MLST method are the same as those employed previously in <it>C. jejuni</it>, <it>C. coli</it>, <it>C. helveticus </it>and <it>C. fetus </it>(i.e. <it>aspA</it>, <it>atpA</it>(<it>uncA</it>), <it>glnA</it>, <it>gltA</it>, <it>glyA, pgm </it>and <it>tkt</it>). A large number of alleles were identified at each locus with the majority of isolates containing a unique sequence type. All <it>Arcobacter </it>isolates typed in this study contain two <it>glyA </it>genes, one linked to <it>lysS </it>(<it>glyA1</it>) and the other linked to <it>ada </it>(<it>glyA2</it>). <it>glyA1 </it>was incorporated into the <it>Arcobacter </it>MLST method while <it>glyA2 </it>was not because it did not increase substantially the level of discrimination.</p> <p>Conclusion</p> <p>No association of MLST alleles or sequence types with host or geographical source was observed with this sample set. Nevertheless, the large number of identified alleles and sequence types indicate that this MLST method will prove useful in both <it>Arcobacter </it>strain discrimination and in epidemiological studies of sporadic <it>Arcobacter</it>-related gastroenteritis. A new <it>Arcobacter </it>MLST database was created <url>http://pubmlst.org/arcobacter/</url>; allele and ST data generated in this study were deposited in this database and are available online.</p

Cost and feasibility: an exploratory case study comparing use of a literature review method with questionnaires, interviews and focus groups to identify barriers for a behaviour-change intervention

Background: It is often recommended that behaviour-change interventions be tailored to barriers. There is a scarcity of research into the best method of barrier identification, although combining methods has been suggested to be beneficial. This paper compares the feasibility and costs of three different methods of barrier identification used in three implementation projects conducted in primary care. Methods: Underpinned by a theory-base, project one used a questionnaire and interviews; project two used a single focus group and questionnaire, and project three used a literature review of published barriers. The feasibility of each project, as experienced by the research team, and labour costs are summarised. Results: The literature review of published barriers was the least costly and most feasible method, being quick to conduct and avoiding the challenges of recruitment experienced when using interviews or a questionnaire. The feasibility of using questionnaires was further reduced by the time taken develop the instruments. Conducting a single focus group was also found to be a more feasible method, taking less time than interviews to collect and analyse the barriers. Conclusions: Considering the ease of recruitment, time required and cost of the different methods to collect barriers is crucial at the start of implementation studies. The literature review method is the least costly and most feasible method. Use of a single focus group was found to be more feasible than conducting individual interviews or administering a questionnaire, with less recruitment challenges experienced, and quicker data collection. Future research would benefit from comparing the robustness of the methods in terms of the comprehensiveness of barriers identified

Etiology of Acute Diarrheal Disease and Antimicrobial Susceptibility Pattern in Children Younger Than 5 Years Old in Nepal

Diarrhea is a common cause of morbidity and mortality among children younger than 5 years in developing countries. Children from 3 to 60 months of age were recruited from two hospitals in Nepal— Bharatpur Hospital, Bharatpur, and Kanti Children’s Hospital, Kathmandu—in 2006 to 2009. Stool specimens collected from 1,200 children with acute diarrhea (cases) and 1,200 children without diarrhea (control subjects) were examined for a broad range of enteropathogens by standard microbiology, including microscopy, enzyme immunoassay for viral pathogens (adenovirus, astrovirus, and rotavirus) and protozoa (Giardia, Cryptosporidium, and Entamoeba histolytica), as well as by using reverse transcription real-time polymerase for norovirus. Antimicrobial susceptibility testing was performed using the disk diffusion method. Overall, rotavirus (22% versus 2%), norovirus (13% versus 7%), adenovirus (3% versus 0%), Shigella (6% versus 1%), enterotoxigenic Escherichia coli (8% versus 4%), Vibrio (7% versus 0%), and Aeromonas (9% versus 3%) were identified significantly more frequently in cases than control subjects. Campylobacter, Plesiomonas, Salmonella, and diarrheagenic E. coli (enteropathogenic, enteroinvasive, enteroaggregative) were identified in similar proportions in diarrheal and non-diarrheal stools. Campylobacter was resistant to second-generation quinolone drugs (ciprofloxacin and norfloxacin), whereas Vibrio and Shigella were resistant to nalidixic acid and trimethoprim/sulfamethoxazole. This study documents the important role of rotavirus and norovirus in acute diarrhea in children younger than 5 years, followed by the bacteria Shigella, enterotoxigenic E. coli, Vibrio cholera, and Aeromonas. Data on the prevalence and epidemiology of enteropathogens identify potential pathogens for public health interventions, whereas pathogen antibiotic resistance pattern data may provide guidance on choice of therapy in clinical settings.publishedVersio