277 research outputs found

    Supramolecularly directed rotary motion in a photoresponsive receptor

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    Stimuli-controlled motion at the molecular level has fascinated chemists already for several decades. Taking inspiration from the myriad of dynamic and machine-like functions in nature, a number of strategies have been developed to control motion in purely synthetic systems. Unidirectional rotary motion, such as is observed in ATP synthase and other motor proteins, remains highly challenging to achieve. Current artificial molecular motor systems rely on intrinsic asymmetry or a specific sequence of chemical transformations. Here, we present an alternative design in which the rotation is directed by a chiral guest molecule, which is able to bind non-covalently to a light-responsive receptor. It is demonstrated that the rotary direction is governed by the guest chirality and hence, can be selected and changed at will. This feature offers unique control of directional rotation and will prove highly important in the further development of molecular machinery

    Action planning and the timescale of evidence accumulation

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    Perceptual decisions are based on the temporal integration of sensory evidence for different states of the outside world. The timescale of this integration process varies widely across behavioral contexts and individuals, and it is diagnostic for the underlying neural mechanisms. In many situations, the decision-maker knows the required mapping between perceptual evidence and motor response (henceforth termed “sensory-motor contingency”) before decision formation. Here, the integrated evidence can be directly translated into a motor plan and, indeed, neural signatures of the integration process are evident as build-up activity in premotor brain regions. In other situations, however, the sensory-motor contingencies are unknown at the time of decision formation. We used behavioral psychophysics and computational modeling to test if knowledge about sensory-motor contingencies affects the timescale of perceptual evidence integration. We asked human observers to perform the same motion discrimination task, with or without trial-to-trial variations of the mapping between perceptual choice and motor response. When the mapping varied, it was either instructed before or after the stimulus presentation. We quantified the timescale of evidence integration under these different sensory-motor mapping conditions by means of two approaches. First, we analyzed subjects’ discrimination threshold as a function of stimulus duration. Second, we fitted a dynamical decision-making model to subjects’ choice behavior. The results from both approaches indicated that observers (i) integrated motion information for several hundred ms, (ii) used a shorter than optimal integration timescale, and (iii) used the same integration timescale under all sensory-motor mappings. We conclude that the mechanisms limiting the timescale of perceptual decisions are largely independent from long-term learning (under fixed mapping) or rapid acquisition (under variable mapping) of sensory-motor contingencies. This conclusion has implications for neurophysiological and neuroimaging studies of perceptual decision-making

    Deficient supplies of drugs for life threatening diseases in an African community

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    <p>Abstract</p> <p>Background</p> <p>In Malawi essential drugs are provided free of charge to patients at all public health facilities in order to ensure equitable access to health care. The country thereby spends about 30% of the national health budget on drugs. In order to investigate the level of drug shortages and eventually find the reasons for the drugs shortages in Malawi, we studied the management of the drug supplies for common and life threatening diseases such as pneumonia and malaria in a random selection of health centres.</p> <p>Methods</p> <p>In July and August 2005 we visited eight out of a total of 37 health centres chosen at random in the Lilongwe District, Malawi. We recorded the logistics of eight essential and widely used drugs which according to the treatment guidelines should be available at all health centres. Five drugs are used regularly to treat pneumonia and three others to treat acute malaria. Out-of-stock situations in the course of one year were recorded retrospectively. We compared the quantity of each drug recorded on the Stock Cards with the actual stock of the drug on the shelves at the time of audit. We reviewed 8,968 Patient Records containing information on type and amount of drugs prescribed during one month.</p> <p>Results</p> <p>On average, drugs for treating pneumonia were out of stock for six months during one year of observation (median value 167 days); anti-malarial drugs were lacking for periods ranging from 42 to138 days. The cross-sectional audit was even more negative, but here too the situation was more positive for anti-malarial drugs. The main reason for the shortage of drugs was insufficient deliveries from the Regional Medical Store. Benzyl penicillin was in shortest supply (4% received). The median value for non-availability was 240 days in the course of a year. The supply was better for anti-malarial drugs, except for quinine injections (9 %). Only 66 % of Stock Card records of quantities received were reflected in Patient Records showing quantities dispensed.</p> <p>Conclusion</p> <p>We conclude that for the eight index drugs the levels of supply are unacceptable. The main reason for the observed shortage of drugs at the health centres was insufficient deliveries from the Regional Medical Store. A difference between the information recorded on the Stock Cards at the health centres and that recorded in the Patient Records may have contributed to the overall poor drug supply situation. In order to ensure equitable access to life saving drugs, logistics in general should be put in order before specific disease management programmes are initiated.</p

    A comparative analysis of the Libyan national essential medicines list and the WHO model list of essential medicines

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    Aim and Objectives: To examine the concordance of the Libyan Pharmaceutical List of Essential Medicines (LPLEM) with the World Health Organization Model List of Essential Medicines 2009 (WMLEM 2009). Methods: The concordance between generic medicines listed in the WMLEM 2009 (standard reference list) and the LPLEM 2006 (comparator list) was evaluated. Results: The total number of Basic Essential Medicines (BEMs) listed on the WMLEM 2009 was 347. The total number of generic medicines listed on the LPLEM was 584. Although the LPLEM has more listed medicines, only 270 (77.6%) of BEMs from the WMLEM were listed as available. However, 25 of the 77 missing medicines were deemed to have appropriate alternatives. A total of 52 medicines from the WMLEM 2009 were therefore missing from the LPLEM. Discrepancies compared to the WMLEM 2009 were identified in 15 out of 29 therapeutic sections. The highest discrepancy rate from the WMLEM 2009 was in the anti-infective section (35 missing medicines). Missing BEMs were noted in many subclassifications of the anti-infective medicines section, but omissions were particularly prevalent in the antibacterial medicines subsection (11 missing medicines). Antituberculosis medications had the highest discrepancy rate for antibacterial BEMs with one-third of the single medicines recommended by the WHO in the WMLEM 2009 not listed on the LPLEM. Of the 314 additional medicines on the LPLEM, 18 were deemed to be irrational non-essential medicines. Conclusion: The LPLEM does not include several essential medicines recommended by the WHO in the WMLEM 2009. These discrepancies may have serious public health implications for management of some infectious diseases, particularly, tuberculosis and HIV

    A need for the standardization of the pharmaceutical sector in Libya

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    Medicines are health technologies that can translate into tangible benefits for numerous acute as well as chronic health conditions. A nation's pharmaceutical sector needs to be appropriately structured and managed in order to ensure a safe, effective and quality supply of medicines to society. The process of medicines management involves the sequential management of five critical activity areas; namely; registration, selection, procurement, distribution and use. Formalized and standardized management of all five critical activity areas positively influences the availability, quality and affordability of medicines and ultimately increases the reliability and quality of the national healthcare system

    Rapid Implementation of an Integrated Large-Scale HIV Counseling and Testing, Malaria, and Diarrhea Prevention Campaign in Rural Kenya

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    BACKGROUND: Integrated disease prevention in low resource settings can increase coverage, equity and efficiency in controlling high burden infectious diseases. A public-private partnership with the Ministry of Health, CDC, Vestergaard Frandsen and CHF International implemented a one-week integrated multi-disease prevention campaign. METHOD: Residents of Lurambi, Western Kenya were eligible for participation. The aim was to offer services to at least 80% of those aged 15-49. 31 temporary sites in strategically dispersed locations offered: HIV counseling and testing, 60 male condoms, an insecticide-treated bednet, a household water filter for women or an individual filter for men, and for those testing positive, a 3-month supply of cotrimoxazole and referral for follow-up care and treatment. FINDINGS: Over 7 days, 47,311 people attended the campaign with a 96% uptake of the multi-disease preventive package. Of these, 99.7% were tested for HIV (87% in the target 15-49 age group); 80% had previously never tested. 4% of those tested were positive, 61% were women (5% of women and 3% of men), 6% had median CD4 counts of 541 cell/µL (IQR; 356, 754). 386 certified counselors attended to an average 17 participants per day, consistent with recommended national figures for mass campaigns. Among women, HIV infection varied by age, and was more likely with an ended marriage (e.g. widowed vs. never married, OR.3.91; 95% CI. 2.87-5.34), and lack of occupation. In men, quantitatively stronger relationships were found (e.g. widowed vs. never married, OR.7.0; 95% CI. 3.5-13.9). Always using condoms with a non-steady partner was more common among HIV-infected women participants who knew their status compared to those who did not (OR.5.4 95% CI. 2.3-12.8). CONCLUSION: Through integrated campaigns it is feasible to efficiently cover large proportions of eligible adults in rural underserved communities with multiple disease preventive services simultaneously achieving various national and international health development goals

    Monitoring of National Drug Policy (NDP) and its standardized indicators; conformity to decisions of the national drug selecting committee in Iran

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    BACKGROUND: Pharmaceuticals have made an important contribution to global reductions in morbidity and mortality. To help save lives and improve health, it is important to be sure about equity to access to drugs, drug efficacy, quality and safety, and rational use of drugs, which are standardized National Drug Policy (NDP) objectives. NDP's indicators are useful to evaluate the pharmaceutical system performance in a country. Iran has adapted a National Drug List (NDL). Since management of drug supply in Iran takes place only for drugs that have been selected in NDL and this list is selected by the member of Iran Drug Selecting Committee (IDSC), thus evaluation of IDSC's decision making during last 5 years is an appropriate way to evaluate the implementation of drug supply system in the country. METHODS: To identify strengths and weaknesses of pharmaceutical policy formation and implementation in Iran, four standard questionnaires of the World Health Organization (WHO) were used. To assess the agreement between decisions of IDSC and standardized NDP indicators in the last 5 years (1998–2002), a weighted questionnaire by nominal group technique based on the questions that should be answered during discussion about one drug in IDSC was designed and used. RESULTS: There is a totally generics based NDP with 95% local production, that provides affordable access to drugs. The system, structures, and mechanisms were in place; however, they did not function properly in some topics. Assessment of 59 dossiers of approved drugs for adding to NDL during last 5 years showed that IDSC's members pay more attention to efficacy, safety, and rationality in use rather than accessibility and affordability. CONCLUSION: Revision of drug system in term of implementation of the processes to achieve NDP's objectives is necessary to save public health. Clarification of NDP's objectives and their impact for IDSC's members will result in improvement of the equity in access to pharmaceuticals

    Factors influencing the utilization of research findings by health policy-makers in a developing country: the selection of Mali's essential medicines

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    BACKGROUND: Research findings are increasingly being recognized as an important input in the formation of health policy. There is concern that research findings are not being utilized by health policy-makers to the extent that they could be. The factors influencing the utilization of various types of research by health policy-makers are beginning to emerge in the literature, however there is still little known about these factors in developing countries. The object of this study was to explore these factors by examining the policy-making process for a pharmaceutical policy common in developing countries; an essential medicines list. METHODS: A study of the selection and updating of Mali's national essential medicines list was undertaken using qualitative methods. In-depth semi-structured interviews and a natural group discussion were held with national policy-makers, most specifically members of the national commission that selects and updates the country's list. The resulting text was analyzed using a phenomenological approach. A document analysis was also performed. RESULTS: Several factors emerged from the textual data that appear to be influencing the utilization of health research findings for these policy-makers. These factors include: access to information, relevance of the research, use of research perceived as a time consuming process, trust in the research, authority of those who presented their view, competency in research methods, priority of research in the policy process, and accountability. CONCLUSION: Improving the transfer of research to policy will require effort on the part of researchers, policy-makers, and third parties. This will include: collaboration between researchers and policy-makers, increased production and dissemination of relevant and useful research, and continued and improved technical support from networks and multi-national organizations. Policy-makers from developing countries will then be better equipped to make informed decisions concerning their health policy issues
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