367 research outputs found

    Regenerative memory in time-delayed neuromorphic photonic resonators

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    We investigate a photonic regenerative memory based upon a neuromorphic oscillator with a delayed self-feedback (autaptic) connection. We disclose the existence of a unique temporal response characteristic of localized structures enabling an ideal support for bits in an optical buffer memory for storage and reshaping of data information. We link our experimental implementation, based upon a nanoscale nonlinear resonant tunneling diode driving a laser, to the paradigm of neuronal activity, the FitzHugh-Nagumo model with delayed feedback. This proof-of-concept photonic regenerative memory might constitute a building block for a new class of neuron-inspired photonic memories that can handle high bit-rate optical signals

    Computational Biology and Bioinformatics in Nigeria

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    Over the past few decades, major advances in the field of molecular biology, coupled with advances in genomic technologies, have led to an explosive growth in the biological data generated by the scientific community. The critical need to process and analyze such a deluge of data and turn it into useful knowledge has caused bioinformatics to gain prominence and importance. Bioinformatics is an interdisciplinary research area that applies techniques, methodologies, and tools in computer and information science to solve biological problems. In Nigeria, bioinformatics has recently played a vital role in the advancement of biological sciences. As a developing country, the importance of bioinformatics is rapidly gaining acceptance, and bioinformatics groups comprised of biologists, computer scientists, and computer engineers are being constituted at Nigerian universities and research institutes. In this article, we present an overview of bioinformatics education and research in Nigeria. We also discuss professional societies and academic and research institutions that play central roles in advancing the discipline in Nigeria. Finally, we propose strategies that can bolster bioinformatics education and support from policy makers in Nigeria, with potential positive implications for other developing countries. © 2014 Fatumo et al.SAF was supported by H3ABioNet NABDA Node, Abuja, Nigeria with NIH Common Fund Award/NHGRI Grant Number U41HG006941 and Genetic Epidemiology Group at Wellcome Trust Sanger Institute.Published versio

    Mycobacterium tuberculosis lineage 4 comprises globally distributed and geographically restricted sublineages

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    Generalist and specialist species differ in the breadth of their ecological niches. Little is known about the niche width of obligate human pathogens. Here we analyzed a global collection of Mycobacterium tuberculosis lineage 4 clinical isolates, the most geographically widespread cause of human tuberculosis. We show that lineage 4 comprises globally distributed and geographically restricted sublineages, suggesting a distinction between generalists and specialists. Population genomic analyses showed that, whereas the majority of human T cell epitopes were conserved in all sublineages, the proportion of variable epitopes was higher in generalists. Our data further support a European origin for the most common generalist sublineage. Hence, the global success of lineage 4 reflects distinct strategies adopted by different sublineages and the influence of human migration.We thank S. Lecher, S. Li and J. Zallet for technical support. Calculations were performed at the sciCORE scientific computing core facility at the University of Basel. This work was supported by the Swiss National Science Foundation (grants 310030_166687 (S.G.) and 320030_153442 (M.E.) and Swiss HIV Cohort Study grant 740 to L.F.), the European Research Council (309540-EVODRTB to S.G.), TB-PAN-NET (FP7-223681 to S.N.), PathoNgenTrace projects (FP7-278864-2 to S.N.), SystemsX.ch (S.G.), the German Center for Infection Research (DZIF; S.N.), the Novartis Foundation (S.G.), the Natural Science Foundation of China (91631301 to Q.G.), and the National Institute of Allergy and Infectious Diseases (5U01-AI069924-05) of the US National Institutes of Health (M.E.)

    Diphyllobothriasis in a nine-year-old child in India: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>The <it>Diphyllobothrium </it>genus belongs to the <it>Diphyllobothridea </it>order of tapeworms. <it>Diphyllobothrium </it>spp., which is commonly known as fish tapeworm, is generally transmitted in humans, but also in other species, such as bears, dogs, cats, foxes, and other terrestrial carnivores. Although worldwide in distribution, the original heartland of <it>Diphyllobothrium </it>spp. spreads across Scandinavia, northern Russia, and western Serbia. We report a rare case that occurred in India.</p> <p>Case presentation</p> <p>A nine-year-old south Indian girl was brought to the casualty at the Prathima Institute of Medical Sciences with complaints of vomiting and loose stools that had started three days earlier. The vomit did not have a foul smell and contained no blood or mucus, but it did contain undigested food particles. The patient described a history of recurrent abdominal pain. She was a non-vegetarian and said she had a history of eating fish.</p> <p>Conclusion</p> <p>The incidence of <it>Diphyllobothrium </it>spp. infection is infrequent in India. Since this is only the fourth reported case in India, and since the previously reported cases also involved observed pediatric patients, we emphasize the need for clinical microbiologists and pediatricians to suspect fish tapeworm infection and recommend epidemiological study of <it>Diphyllobothrium </it>spp. infection.</p

    Detection and phenotypic characterization of methicillin-resistant Staphylococcus aureus from clinical and community samples in Abakaliki, Ebonyi State, Nigeria

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    Objective: The objective of this study was to isolate and phenotypically characterize methicillin-resistant Staphylococcus aureus (MRSA)from clinical and community samples in Abakaliki, Nigeria. Methods: A total of 709 clinical (303) and community samples (406) samples were obtained for this study. MRSA isolates were detected using Kirby-Bauer disc diffusion method with the inclusion of 1 \ub5g oxacillin and cefoxitin antibiotic disc. The isolates were screened for the \u3b2-lactamase production using nitrocefin sticks. Results: A total of 44 MRSA isolates were obtained from the samples with prevalence frequency of 22.6 % and 20.8 % from clinical and community samples respectively. The clinical isolates were completely resistant (100 %) to ceftazidime, tetracycline and penicillin. Gentamicin and ciprofloxacin were the most effective antibiotics against the clinical and community isolates respectively with a susceptibility frequency of 63.2 % and 80 %. Exactly 38.1 % and 24.2 % of the clinical and community S. aureus isolates were positive for beta-lactamase production respectively. The HA-MRSA and CA-MRSA isolates had MARI values within the range of 0.3 to 1.0. Conclusion: This present findings of multi-drug resistance MRSA is very worrisome as it further highlights the pressing need to keep a strict watch on MRSA emerging from this study area. DOI: https://dx.doi.org/10.4314/ahs.v19i2.26 Cite as: Ariom TO, Iroha IR, Moses IB, Iroha CS, Ude UI, Kalu AC. Detection and phenotypic characterization of methicillin-resistant staphylococcus aureus from clinical and community samples in Abakaliki, Ebonyi State, Nigeria. Afri Health Sci.2019;19(2): 2026-2035. https:// dx.doi.org/10.4314/ahs.v19i2.2

    Geomicrobiology of the built environment

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    Microbial colonization and growth can have significant effects in the built environment, resulting in a range of effects from discolouration and staining to biodeterioration and decay. In some cases, formation of biofilms, crusts and patinas may confer bioprotection of the substrate. This perspective aims to discuss how geomicrobial transformations in the natural environment - particularly involving rocks, minerals, metals and organic matter - may be applied to understand similar processes occurring on fabricated human structures. However, the built environment may offer further strictures as well as benefits for microbial activity and these should be taken into consideration when considering analogy with natural processes, especially when linking observations of microbial biodiversity to the more obvious manifestations of microbial attack

    The primary therapy chosen for patients with localized prostate cancer between the university hospital and its affiliated hospitals in Nara Uro-oncological research group registration

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    <p>Abstract</p> <p>Background</p> <p>We investigated the differences between the preferential primary therapy conceived by the primary doctors and the primary therapy actually conducted for prostate cancer patients in Nara, Japan.</p> <p>Methods</p> <p>The distribution of primary therapy and clinical characteristics of 2303 prostate cancer patients - diagnosed between 2004 and 2006 at Nara Medical University and its 23 affiliated hospitals - were assessed. Moreover, the preferential primary therapy for the patients at each clinical stage (cT1-T3bN0M0) conceived by the primary doctors was investigated and compared to the actual therapy.</p> <p>Results</p> <p>Of all patients, 51% received primary androgen deprivation therapy (PADT), 30% underwent radical prostatectomy (RP), and 14% received radiation therapy (RT). The preferential primary therapy for cT1-2N0M0 was RP (92%) while 38% of the patients actually received PADT (RP: 40%). For cT3aN0M0, the preferential primary therapy was both RP and external beam radiation therapy (EBRT) while 58% of the patients actually received PADT (RP: 16%, EBRT: 24%). For cT3bN0M0, the most preferential primary therapy was EBRT (46%) while 67% of the patients actually received PADT (EBRT: 21%). This trend was more notable in the affiliated hospitals than in the University hospital. The hospitals with lower volume of RP per year significantly conducted PADT compared with those with higher volume of RP.</p> <p>Conclusions</p> <p>PADT was commonly used to treat localized prostate cancer as well as locally advanced prostate cancer in Japan. There was a definite discrepancy between the preferential primary therapy conceived by the primary doctors and the actual therapy provided to the patients.</p

    High HIV Incidence and Sexual Behavior Change among Pregnant Women in Lilongwe, Malawi: Implications for the Risk of HIV Acquisition

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    HIV incidence is higher among pregnant women than their non-pregnant counterparts in some sub-Saharan African settings. Our aims were (1) to estimate HIV incidence during pregnancy and (2) to compare sexual activity between pregnant, postpartum, and non-pregnant women.We examined a retrospective cohort of 1087 women to identify seroconverters using antenatal and labor ward HIV test results. We also conducted a cross-sectional survey, including a quantitative questionnaire (n = 200) and in-depth interviews (n = 20) among women in early pregnancy, late pregnancy, postpartum, and non-pregnancy. Outcomes included measures of sexual activity, reported spouse's risky behavior, and beliefs about abstinence.11 of 1087 women seroconverted during pregnancy yielding a 1% seroconversion risk and an incidence rate of 4.0/100 person years (95% CI 2.2-7.2). The reported sexual activity of the early pregnancy and non-pregnancy groups was similar, but significantly higher than the late pregnancy and postpartum groups (p<0.001). During pregnancy, sex acts decreased as gestation increased (p = 0.001). There was no reported difference in the spouse's risky behavior. Most women believed that sex should cease between the 6(th) and 8(th) month of pregnancy and should not resume until 6 months postpartum. Some talked about conflict between their cultural obligation to abstain and fear of HIV infection if their spouses find other partners.HIV incidence is high among pregnant women in Malawi, and sexual activity decreases during pregnancy and postpartum. Pregnant women need to be informed of their increased risk for HIV and the importance of using condoms throughout pregnancy and the postpartum period

    Dental erosive wear and salivary flow rate in physically active young adults

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    Background Little attention has been directed towards identifying the relationship between physical exercise, dental erosive wear and salivary secretion. The study aimed i) to describe the prevalence and severity of dental erosive wear among a group of physically active young adults, ii) to describe the patterns of dietary consumption and lifestyle among these individuals and iii) to study possible effect of exercise on salivary flow rate. Methods Young members (age range 18-32 years) of a fitness-centre were invited to participate in the study. Inclusion criteria were healthy young adults training hard at least twice a week. A non-exercising comparison group was selected from an ongoing study among 18-year-olds. Two hundred and twenty participants accepted an intraoral examination and completed a questionnaire. Seventy of the exercising participants provided saliva samples. The examination was performed at the fitness-centre or at a dental clinic (comparison group), using tested erosive wear system (VEDE). Saliva sampling (unstimulated and stimulated) was performed before and after exercise. Occlusal surfaces of the first molars in both jaws and the labial and palatal surfaces of the upper incisors and canines were selected as index teeth. Results Dental erosive wear was registered in 64% of the exercising participants, more often in the older age group, and in 20% of the comparison group. Enamel lesions were most observed in the upper central incisors (33%); dentine lesions in lower first molar (27%). One fourth of the participants had erosive wear into dentine, significantly more in males than in females (p = 0.047). More participants with erosive wear had decreased salivary flow during exercise compared with the non-erosion group (p < 0.01). The stimulated salivary flow rate was in the lower rage (≤ 1 ml/min) among more than one third of the participants, and more erosive lesions were registered than in subjects with higher flow rates (p < 0.01). Conclusion The study showed that a high proportion of physically active young adults have erosive lesions and indicate that hard exercise and decreased stimulated salivary flow rate may be associated with such wear
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