2,769 research outputs found

    Regionalizing telecommunications reform in West Africa

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    In recent years, there has been an increasing recognition that significant welfare gains could be realized through deep forms of regional integration which entail harmonization of legal, regulatory and institutional frameworks. Reforms that reduce cross-border transaction costs and improve the performance of “backbone” infrastructure services are arguably even more important for the creation of an open, unified regional economic space than trade policy reforms narrowly defined. This paper assesses the potential gains from regionalized telecommunications policy in West Africa. To this end, the paper: (i) discusses how regional cooperation can overcome national limits in technical expertise, enhance the capacity of nations credibly to commit to stable regulatory policy, and ultimately facilitate infrastructure investment in the region; (ii) identifies trade-distorting regulations that inhibit opportunities for regional trade and economic development, and so are good candidates for regional trade negotiations to reduce indirect trade barriers; and (iii) describes substantive elements of a harmonized regional regulatory policy that can deliver immediate performance benefits.E-Business,Environmental Economics&Policies,ICT Policy and Strategies,Transport Economics Policy&Planning,Emerging Markets

    Antimicrobial resistance patterns of phenotype Extended Spectrum Beta-Lactamase producing bacterial isolates in a referral hospital in northern Tanzania

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    Background: Production of Extended Spectrum Beta-Lactamase (ESBL) by bacteria is a chronic problem in a health care set up. In order to have adequate information for treatment of bacterial infections especially ESBL producing isolates, it is crucial to understand the trends in the antibiotic-resistance pattern, occurrence and their geographical spread.  The objective of this study was to determine the antimicrobial resistance pattern among phenotype ESBL producing isolates in northern Tanzania.Methods: From July 2013 to January 2014, urine, pus and blood samples were collected from patients suspected to have bacterial infections at Kilimanjaro Christian Medical Centre in Moshi, Tanzania. The isolates were identified based on standard laboratory procedures. Antimicrobial susceptibility tests were carried out using various antimicrobial discs as per the recommendations of Clinical Laboratory Standard Institute.Results: A total of 330 specimens were collected. They consisted of 46 urine, 264 pus (from wound) and 20 blood samples. Among isolated bacteria, ESBL producers were 29.7% (98) and non-producers were 70.5% (232).  Escherichia coli and Klebsiella pneumoniae were the most isolated bacteria and dominant ESBL producers.  ESBL production was highly associated with moderate condition at discharge and longer periods of admission. More than 60% of the ESBL producing E. coli were resistant to ceftazidime, cefpodoxime, cefotaxime, amoxycilin, ciprofloxacin, and gentamycin. More than 80% of ESBL producing K. pneumonia and Proteus mirabilis were resistant to ceftazidime and cefotaxime. Fifty four percent of ESBL producing K. pneumonia were resistant to gentamycin.Conclusion: This study shows that ESLB phenotypes among Gram-negative bacteria are common among patients attending a tertiary hospital in northern in Tanzania. The findings suggest that clinical microbiology laboratories should take into account the diagnosis of ESBL producers in order to define the degree of the problem so as to establish a proper treatment protocol

    Contributions of Spore Secondary Metabolites to UV-C Protection and Virulence Vary in Different Aspergillus fumigatus Strains

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    Fungi are versatile organisms which thrive in hostile environments, including the International Space Station (ISS). Several isolates of the human pathogen Aspergillus fumigatus have been found contaminating the ISS, an environment with increased exposure to UV radiation. Secondary metabolites (SMs) in spores, such as melanins, have been shown to protect spores from UV radiation in other fungi. To test the hypothesis that melanin and other known spore SMs provide UV protection to A. fumigatus isolates, we subjected SM spore mutants to UV-C radiation. We found that 1,8-dihydroxynaphthalene (DHN)-melanin mutants of two clinical A. fumigatus strains (Af293 and CEA17) but not an ISS-isolated strain (IF1SW-F4) were more sensitive to UV-C than their respective wild-type (WT) strains. Because DHN-melanin has been shown to shield A. fumigatus from the host immune system, we examined all DHN mutants for virulence in the zebrafish model of invasive aspergillosis. Following recent studies highlighting the pathogenic variability of different A. fumigatus isolates, we found DHN-melanin to be a virulence factor in CEA17 and IF1SW-F4 but not Af293. Three additional spore metabolites were examined in Af293, where fumiquinazoline also showed UV-C-protective properties, but two other spore metabolites, monomethylsulochrin and fumigaclavine, provided no UV-C-protective properties. Virulence tests of these three SM spore mutants indicated a slight increase in virulence of the monomethylsulochrin deletion strain. Taken together, this work suggests differential roles of specific spore metabolites across Aspergillus isolates and by types of environmental stress

    Gene network exploration of crosstalk between apoptosis and autophagy in chronic myelogenous leukemia

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    Copyright © 2015 Fengfeng Wang et al. Background. Gene expression levels change to adapt the stress, such as starvation, toxin, and radiation. The changes are signals transmitted through molecular interactions, eventually leading to two cellular fates, apoptosis and autophagy. Due to genetic variations, the signals may not be effectively transmitted to modulate apoptotic and autophagic responses. Such aberrant modulation may lead to carcinogenesis and drug resistance. The balance between apoptosis and autophagy becomes very crucial in coping with the stress. Though there have been evidences illustrating the apoptosis-autophagy interplay, the underlying mechanism and the participation of the regulators including transcription factors (TFs) and microRNAs (miRNAs) remain unclear. Results. Gene network is a graphical illustration for exploring the functional linkages and the potential coordinate regulations of genes. Microarray dataset for the study of chronic myeloid leukemia was obtained from Gene Expression Omnibus. The expression profiles of those genes related to apoptosis and autophagy, including MCL1, BCL2, ATG, beclin-1, BAX, BAK, E2F, cMYC, PI3K, AKT, BAD, and LC3, were extracted from the dataset to construct the gene networks. Conclusion. The network analysis of these genes explored the underlying mechanisms and the roles of TFs and miRNAs for the crosstalk between apoptosis and autophagy.Link_to_subscribed_fulltex

    Interacting rhythms enhance sensitivity of target detection in a fronto-parietal computational model of visual attention

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    Even during sustained attention, enhanced processing of attended stimuli waxes and wanes rhythmically, with periods of enhanced and relatively diminished visual processing (and subsequent target detection) alternating at 4 or 8 Hz in a sustained visual attention task. These alternating attentional states occur alongside alternating dynamical states, in which lateral intraparietal cortex (LIP), the frontal eye field (FEF), and the mediodorsal pulvinar exhibit different activity and functional connectivity at α, β, and γ frequencies—rhythms associated with visual processing, working memory, and motor suppression. To assess whether and how these multiple interacting rhythms contribute to periodicity in attention, we propose a detailed computational model of FEF and LIP, which reproduced the rhythmic dynamics and behavioral consequences of observed attentional states when driven by θ-rhythmic inputs simulating experimentally-observed pulvinar activity. This model reveals that the frequencies and mechanisms of the observed rhythms allow for peak sensitivity in visual target detection while maintaining functional flexibility.https://www.biorxiv.org/content/10.1101/2021.02.18.431872v

    Uncoupling of neurogenesis and differentiation during retinal development

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    Conventionally, neuronal development is regarded to follow a stereotypic sequence of neurogenesis, migration, and differentiation. We demonstrate that this notion is not a general principle of neuronal development by documenting the timing of mitosis in relation to multiple differentiation events for bipolar cells (BCs) in the zebrafish retina using in vivo imaging. We found that BC progenitors undergo terminal neurogenic divisions while in markedly disparate stages of neuronal differentiation. Remarkably, the differentiation state of individual BC progenitors at mitosis is not arbitrary but matches the differentiation state of post-mitotic BCs in their surround. By experimentally shifting the relative timing of progenitor division and differentiation, we provide evidence that neurogenesis and differentiation can occur independently of each other. We propose that the uncoupling of neurogenesis and differentiation could provide neurogenic programs with flexibility, while allowing for synchronous neuronal development within a continuously expanding cell pool

    Upper Extremity Superficial Vein Thromboses Presenting as Acute Neck Pain in a Young and Healthy Male: A Case Report

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    # Background and Purpose Neck pain in the United States is pervasive and contributes to disability. While the majority of neck pain in young and healthy individuals is neuromusculoskeletal in nature, screening for red flags is necessary for ruling-out serious medical pathologies. The purpose of this case report is to describe a young and healthy male subject with a primary complaint of acute neck pain with multiple underlying upper extremity superficial vein thromboses (UESVTs). # Case Description The subject was a 27-year-old male active-duty Soldier referred to physical therapy by his primary care provider (PCP) for acute left-sided neck pain. Prior to physical therapy, the subject had been treated with cyclobenzaprine, oxycodone-acetaminophen, trigger point injection and had undergone a D-dimer to rule out a potential thrombus due to air travel and lower extremity immobilization. # Outcomes The subject underwent a D-dimer, Doppler ultrasound, pharmacological treatment of Rivaroxaban, and was referred to hematology/oncology to rule out systemic causes of SVTs. Evidence of subtle increases in blood pressure over the course of three months, a positive D-dimer, and symptoms incongruent with clinical presentation contributed to referral to a hematology/oncology specialist and a diagnosis of multiple UESVTs. The subject was able to return to his previous level of activity by six months and remained free of SVTs at two-year follow-up. # Discussion UESVT events are rare and can be challenging to identify. This case report describes a unique presentation of acute neck pain caused by underlying UESVTs in an otherwise healthy and active young male. # Level of Evidence Level

    The DIAMOND Initiative: Implementing Collaborative Care for Depression in 75 Primary Care Clinics

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    Background: The many randomized trials of the collaborative care model for improving depression in primary care have not described the implementation and maintenance of this model. This paper reports how and the degree to which collaborative care process changes were implemented and maintained for the 75 primary care clinics participating in the DIAMOND Initiative (Depression Improvement Across Minnesota–Offering a New Direction). Methods: Each clinic was trained to implement seven components of the model and participated in ongoing evaluation and facilitation activities. For this study, assessment of clinical process implementation was accomplished via completion of surveys by the physician leader and clinic manager of each clinic site at three points in time. The physician leader of each clinic completed a survey measure of the presence of various practice systems prior to and one and two years after implementation. Clinic managers also completed a survey of organizational readiness and the strategies used for implementation. Results: Survey response rates were 96% to 100%. The systems survey confirmed a very high degree of implementation (with large variation) of DIAMOND depression practice systems (mean of 24.4 ± 14.6%) present at baseline, 57.0 ± 21.0% at one year (P = \u3c0.0001), and 55.9 ± 21.3% at two years. There was a similarly large increase (and variation) in the use of various quality improvement strategies for depression (mean of 29.6 ± 28.1% at baseline, 75.1 ± 22.3% at one year (P = \u3c0.0001), and 74.6 ± 23.0% at two years. Conclusions: This study demonstrates that under the right circumstances, primary care clinics that are prepared to implement evidence-based care can do so if financial barriers are reduced, effective training and facilitation are provided, and the new design introduces the specific mental models, new care processes, and workers and expertise that are needed. Implementation was associated with a marked increase in the number of improvement strategies used, but actual care and outcomes data are needed to associate these changes with patient outcomes and patient-reported care

    Memory Acquisition and Retrieval Impact Different Epigenetic Processes that Regulate Gene Expression

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    Background: A fundamental question in neuroscience is how memories are stored and retrieved in the brain. Long-term memory formation requires transcription, translation and epigenetic processes that control gene expression. Thus, characterizing genome-wide the transcriptional changes that occur after memory acquisition and retrieval is of broad interest and importance. Genome-wide technologies are commonly used to interrogate transcriptional changes in discovery-based approaches. Their ability to increase scientific insight beyond traditional candidate gene approaches, however, is usually hindered by batch effects and other sources of unwanted variation, which are particularly hard to control in the study of brain and behavior. Results: We examined genome-wide gene expression after contextual conditioning in the mouse hippocampus, a brain region essential for learning and memory, at all the time-points in which inhibiting transcription has been shown to impair memory formation. We show that most of the variance in gene expression is not due to conditioning and that by removing unwanted variance through additional normalization we are able provide novel biological insights. In particular, we show that genes downregulated by memory acquisition and retrieval impact different functions: chromatin assembly and RNA processing, respectively. Levels of histone 2A variant H2AB are reduced only following acquisition, a finding we confirmed using quantitative proteomics. On the other hand, splicing factor Rbfox1 and NMDA receptor-dependent microRNA miR-219 are only downregulated after retrieval, accompanied by an increase in protein levels of miR-219 target CAMKIIγ. Conclusions: We provide a thorough characterization of coding and non-coding gene expression during long-term memory formation. We demonstrate that unwanted variance dominates the signal in transcriptional studies of learning and memory and introduce the removal of unwanted variance through normalization as a necessary step for the analysis of genome-wide transcriptional studies in the context of brain and behavior. We show for the first time that histone variants are downregulated after memory acquisition, and splicing factors and microRNAs after memory retrieval. Our results provide mechanistic insights into the molecular basis of cognition by highlighting the differential involvement of epigenetic mechanisms, such as histone variants and post-transcriptional RNA regulation, after acquisition and retrieval of memory
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