60 research outputs found

    Amino Acids Generated from Hydrated Titan Tholins: Comparison with Miller-Urey Electric Discharge Products

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    Various analogues of Titan haze particles (termed tholins) have been made in the laboratory. In certain geologic environments on Titan, these haze particles may come into contact with aqueous ammonia (NH3) solutions, hydrolyzing them into molecules of astrobiological interest. A Titan tholin analogue hydrolyzed in aqueous NH3 at room temperature for 2.5 years was analyzed for amino acids using highly sensitive ultra-high performance liquid chromatography coupled with fluorescence detection and time-of-flight mass spectrometry (UHPLC-FDToF-MS) analysis after derivatization with a fluorescent tag. We compare here the amino acids produced from this reaction sequence with those generated from room temperature Miller-Urey (MU) type electric discharge reactions. We find that most of the amino acids detected in low temperature MU CH4N2H2O electric discharge reactions are generated in Titan simulation reactions, as well as in previous simulations of Triton chemistry. This argues that many processes provide very similar mixtures of amino acids, and possibly other types of organic compounds, in disparate environments, regardless of the order of hydration. Although it is unknown how life began, it is likely that given reducing conditions, similar materials were available throughout the early Solar System and throughout the universe to facilitate chemical evolution

    Evaluation of a Gas Chromatograph-Differential Mobility Spectrometer for Potential Water Monitoring on the International Space Station

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    Environmental monitoring for manned spaceflight has long depended on archival sampling, which was sufficient for short missions. However, the longer mission durations aboard the International Space Station (ISS) have shown that enhanced, real-time monitoring capabilities are necessary in order to protect both the crewmembers and the spacecraft systems. Over the past several years, a number of real-time environmental monitors have been deployed on the ISS. Currently, volatile organic compounds (VOCs) in the station air are monitored by the Air Quality Monitor (AQM), a small, lightweight gas chromatograph-differential mobility spectrometer. For water monitoring, real-time monitors are used for total organic carbon (TOC) and biocide analysis. No information on the actual makeup of the TOC is provided presently, however. An improvement to the current state of environmental monitoring could be realized by modifying a single instrument to analyze both air and water. As the AQM currently provides quantitative, compound-specific information for VOCs in air samples, this instrument provides a logical starting point to evaluate the feasibility of this approach. The major hurdle for this effort lies in the liberation of the target analytes from the water matrix. In this presentation, we will discuss our recent studies, in which an electro-thermal vaporization unit has been interfaced with the AQM to analyze target VOCs at the concentrations at which they are routinely detected in archival water samples from the ISS. We will compare the results of these studies with those obtained from the instrumentation routinely used to analyze archival water samples

    Quality of Artemisinin-based Combination Therapy for malaria found in Ghanaian markets and public health implications of their use.

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    BACKGROUND: Ghana changed their antimalarial drug policy from monotherapies to Artemisinin-based Combination Therapies in 2004 in order to provide more efficacious medicines for treatment of malaria. The policy change can be eroded if poor quality Artemisinin-based Combination Therapies are allowed to remain on the Ghanaian market unchecked by regulatory bodies and law enforcement agencies. The presence and prevalence of substandard and counterfeit Artemisinin-based Combination Therapies need to be determined on open markets in Ghana; a review of the current policy; identifying any gaps and making recommendations on actions to be taken in addressing gaps identified are essential as the data provided and recommendations made will help in ensuring effective control of malaria in Ghana. METHODS: A field survey of antimalarial drugs was conducted in the central part of Ghana. The amount of active pharmaceutical ingredient in each Artemisinin-based Combination Therapy sample identified in the survey was measured using high performance liquid chromatographic analyses. Active pharmaceutical ingredient within the range of 85-115 % was considered as standard and active pharmaceutical ingredient results out of the range were considered as substandard. All samples were screened to confirm stated active pharmaceutical ingredient presence using mass spectrometry. RESULTS: A total of 256 Artemisinin-based Combination Therapies were purchased from known medicine outlets, including market stalls, hospitals/clinics, pharmacies, drug stores. Artemether lumefantrine (52.5 %) and artesunate amodiaquine (43.2 %) were the predominant Artemisinin-based Combination Therapies purchased. Of the 256 Artemisinin-based Combination Therapies purchased, 254 were tested, excluding two samples of Artesunate-SP. About 35 % of Artemisinin-based Combination Therapies were found to be substandard. Nine percent of Artemisinin-based Combination Therapies purchased were past their expiry date; no counterfeit (falsified) medicine samples were detected by either high performance liquid chromatographic or mass spectrometry. CONCLUSION: A high proportion of Artemisinin-based Combination Therapies sold in central Ghana were found to be substandard. Manufacturing of medicines that do not adhere to good manufacturing practices may have contributed to the poor quality of the Artemisinin-based Combination Therapies procured. A strict law enforcement and quality monitoring systems is recommended to ensure effective malaria case management as part of malaria control

    Conducting Miller-Urey Experiments

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    In 1953, Stanley Miller reported the production of biomolecules from simple gaseous starting materials, using apparatus constructed to simulate the primordial Earth's atmosphere-ocean system. Miller introduced 200 ml of water, 100 mmHg of H2, 200mmHg of CH4, and 200mmHg of NH3 into the apparatus, then subjected this mixture, under reflux, to an electric discharge for a week, while the water was simultaneously heated. The purpose of this manuscript is to provide the reader with a general experimental protocol that can be used to conduct a Miller-Urey type spark discharge experiment, using a simplified 3 L reaction flask. Since the experiment involves exposing inflammable gases to a high voltage discharge, it is worth highlighting important steps that reduce the risk of explosion. The general procedures described in this work can be extrapolated to design and conduct a wide variety of electric discharge experiments simulating primitive planetary environments

    Prevalence of substandard and falsified artemisinin-based combination antimalarial medicines on Bioko Island, Equatorial Guinea.

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    INTRODUCTION: Poor-quality artemisinin-containing antimalarials (ACAs), including falsified and substandard formulations, pose serious health concerns in malaria endemic countries. They can harm patients, contribute to the rise in drug resistance and increase the public's mistrust of health systems. Systematic assessment of drug quality is needed to gain knowledge on the prevalence of the problem, to provide Ministries of Health with evidence on which local regulators can take action. METHODS: We used three sampling approaches to purchase 677 ACAs from 278 outlets on Bioko Island, Equatorial Guinea as follows: convenience survey using mystery client (n=16 outlets, 31 samples), full island-wide survey using mystery client (n=174 outlets, 368 samples) and randomised survey using an overt sampling approach (n=88 outlets, 278 samples). The stated active pharmaceutical ingredients (SAPIs) were assessed using high-performance liquid chromatography and confirmed by mass spectrometry at three independent laboratories. RESULTS: Content analysis showed 91.0% of ACAs were of acceptable quality, 1.6% were substandard and 7.4% falsified. No degraded medicines were detected. The prevalence of medicines without the SAPIs was higher for ACAs purchased in the convenience survey compared with the estimates obtained using the full island-wide survey-mystery client and randomised-overt sampling approaches. Comparable results were obtained for full island survey-mystery client and randomised overt. However, the availability of purchased artesunate monotherapies differed substantially according to the sampling approach used (convenience, 45.2%; full island-wide survey-mystery client, 32.6%; random-overt sampling approach, 21.9%). Of concern is that 37.1% (n=62) of these were falsified. CONCLUSION: Falsified ACAs were found on Bioko Island, with the prevalence ranging between 6.1% and 16.1%, depending on the sampling method used. These findings underscore the vital need for national authorities to track the scale of ineffective medicines that jeopardise treatment of life-threatening diseases and value of a representative sampling approach to obtain/measure the true prevalence of poor-quality medicines

    Quality of antimalarials at the epicenter of antimalarial drug resistance: results from an overt and mystery client survey in Cambodia.

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    Widespread availability of monotherapies and falsified antimalarials is thought to have contributed to the historical development of multidrug-resistant malaria in Cambodia. This study aimed to document the quality of artemisinin-containing antimalarials (ACAs) and to compare two methods of collecting antimalarials from drug outlets: through open surveyors and mystery clients (MCs). Few oral artemisinin-based monotherapies and no suspected falsified medicines were found. All 291 samples contained the stated active pharmaceutical ingredient (API) of which 69% were considered good quality by chemical analysis. Overall, medicine quality did not differ by collection method, although open surveyors were less likely to obtain oral artemisinin-based monotherapies than MCs. The results are an encouraging indication of the positive impact of the country's efforts to tackle falsified antimalarials and artemisinin-based monotherapies. However, poor-quality medicines remain an ongoing challenge that demands sustained political will and investment of human and financial resources

    Performance Evaluation of the Operational Air Quality Monitor for Water Testing Aboard the International Space Station

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    Real-time environmental monitoring on ISS is necessary to provide data in a timely fashion and to help ensure astronaut health. Current real-time water TOC monitoring provides high-quality trending information, but compound-specific data is needed. The combination of ETV with the AQM showed that compounds of interest could be liberated from water and analyzed in the same manner as air sampling. Calibration of the AQM using water samples allowed for the quantitative analysis of ISS archival samples. Some calibration issues remain, but the excellent accuracy of DMSD indicates that ETV holds promise for as a sample introduction method for water analysis in spaceflight

    Responding to the Pandemic of Falsified Medicines

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    Over the past decade, the number of countries reporting falsified (fake, spurious/falsely labeled/counterfeit) medicines and the types and quantities of fraudulent drugs being distributed have increased greatly. The obstacles in combating falsified pharmaceuticals include 1) lack of consensus on definitions, 2) paucity of reliable and scalable technology to detect fakes before they reach patients, 3) poor global and national leadership and accountability systems for combating this scourge, and 4) deficient manufacturing and regulatory challenges, especially in China and India where fake products often originate. The major needs to improve the quality of the world's medicines fall into three main areas: 1) research to develop and compare accurate and affordable tools to identify high-quality drugs at all levels of distribution; 2) an international convention and national legislation to facilitate production and utilization of high-quality drugs and protect all countries from the criminal and the negligent who make, distribute, and sell life-threatening products; and 3) a highly qualified, well-supported international science and public health organization that will establish standards, drug-quality surveillance, and training programs like the U.S. Food and Drug Administration. Such leadership would give authoritative guidance for countries in cooperation with national medical regulatory agencies, pharmaceutical companies, and international agencies, all of which have an urgent interest and investment in ensuring that patients throughout the world have access to good quality medicines. The organization would also advocate strongly for including targets for achieving good quality medicines in the United Nations Millennium Development Goals and Sustainable Development Goals
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