A mathematical model for the sequestering of chemical contaminants by magnetic particles

A mathematical model is developed and implemented to characterize the pickup of various liquid chemical contaminants by polyethylene-coated magnetic particles. The model and its associated experimental and analytical protocols were applied to a wide range of liquid chemicals in order to gain insights into the physical basis for the pickup phenomenon. The characteristics of the pickup isotherms range between “ideal” and “nonideal” behaviors that are reflected in the mathematical model by a single parameter, �0, where �0=1 corresponds to ideal behavior and �0�1 corresponds to a departure from idealized behavior that is directly quantified by the magnitude of �0. The parameter �0 is also related to the efficiency of pickup, and since most isotherms observed in the study deviate from ideality, the high efficiency of pickup observed in these systems has been attributed in part to this deviation. The proposed model and its associated experimental and analytical protocols demonstrate great potential for the systematic evaluation of the uptake of chemical contaminants using magnetic particle technology

Properties of Char Produced from Pyrolysis of Southern Pine

Bench scale pyrolyses were carried out on southern pine at conditions of 250, 350, 400, 500, and 800 C for 1, 2, and 4 hours in a flowing nitrogen atmosphere at flow rates of 135 and 405 milliliters per minute. Data presented in this paper represent work on the properties of the chars produced under these conditions. Results of oxygen bomb calorimetry, density and specific gravity measurements, carbon and hydrogen analyses, and gravimetric yields were statistically analyzed to determine the influence of process conditions on char properties. In general, char yield and percentage of hydrogen and oxygen decreased, while the carbon percentage increased with increasing temperature

What factors are associated with ambulance use for non-emergency problems in children?:A systematic mapping review and qualitative synthesis

Objective To explore what factors are associated with ambulance use for non-emergency problems in children. Methods This study is a systematic mapping review and qualitative synthesis of published journal articles and grey literature. Searches were conducted on the following databases, for articles published between January 1980 and July 2020: MEDLINE, EMBASE, PsycINFO, CINAHL and AMED. A Google Scholar and a Web of Science search were undertaken to identify reports or proceedings not indexed in the above. Book chapters and theses were searched via the OpenSigle, EThOS and DART databases. A literature advisory group, including experts in the field, were contacted for relevant grey literature and unpublished reports. The inclusion criteria incorporated articles published in the English language reporting findings for the reasons behind why there are so many calls to the ambulance service for non-urgent problems in children. Data extraction was divided into two stages: extraction of data to generate a broad systematic literature € map', and extraction of data from highly relevant papers using qualitative methods to undertake a focused qualitative synthesis. An initial table of themes associated with reasons for non-emergency calls to the ambulance for children formed the € thematic map' element. The uniting feature running through all of the identified themes was the determination of € inappropriateness' or € appropriateness' of an ambulance call out, which was then adopted as the concept of focus for our qualitative synthesis. Results There were 27 articles used in the systematic mapping review and 17 in the qualitative synthesis stage of the review. Four themes were developed in the systematic mapping stage: socioeconomic status/geographical location, practical reasons, fear of consequences and parental education. Three analytical themes were developed in the qualitative synthesis stage including practicalities and logistics of obtaining care, arbitrary scoring system and retrospection. Conclusions There is a lack of public and caregiver understanding about the use of ambulances for paediatrics. There are factors that appear specific to choosing ambulance care for children that are not so prominent in adults (fever, reassurance, fear of consequences). Future areas for attention to decrease ambulance activation for paediatric low-acuity reports were highlighted as: identifying strategies for helping caregivers to mitigate perceived risk, increasing availability of primary care, targeted education to particular geographical areas, education to first-time parents with infants and providing alternate means of transportation. PROSPERO registration number CRD42019160395

Chrysanthemum species used as food and medicine: Understanding quality differences on the global market

Background Chrysanthemum flowers [Ch. x morifolium (Ramat.) Hemsl. and Ch. indicum L.] are a globally used and pharmacologically interesting botanical drug, however, with variable product quality. Objective We aim at understanding the chemical variability of primary material available commercially based on different origins and associated quality problems like contamination with heavy metals. This needs to be assessed in the context of the current regulations for this botanical drug and associated problems. Material and Methods 15 C. indicum L. and 50 C. x morifolium (Ramat.) Hemsl., including a range of geographical cultivars recognized in China, samples from the USA, Europe and China were analyzed using High Performance Thin Layer Chromatography (HPTLC) to compare their general chemical profile. Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) was used to quantify heavy metal contamination. Results The: HPTLC fingerprints of C. indicum samples are clearly distinguishable from C. x morifolium. Fingerprints of samples from the same cultivars collected from markets in different countries (USA and China) show different patterns. Large variance of fingerprints within each cultivar group was observed. The heavy metal analysis showed excessive amounts of some harmful heavy metal in some commercial products with excessive cadmium being the most frequent problem. Conclusions The Chinese medicinal cultivars vary. Differences between samples sourced from the USA and China might be ascribable to geographical factors (e.g. soil composition), degradation during transport/storage or adulteration, but geographical differences should also be taken into account. Importantly, a much more detailed definition of the drug are needed for better quality control. In addition, with continuous contamination problem observed, a more widespread regulation is an essential requirement for better quality

Regression discontinuity analysis for pharmacovigilance:statin example reflected trial findings showing little evidence of harm

OBJECTIVES: The study aims to explore the use of regression discontinuity analysis (RDA) to examine effects of prescription of statins on total cholesterol and adverse outcomes (type 2 diabetes, rhabdomyolysis and myopathy, myalgia and myositis, liver disease, CVD, and mortality). STUDY DESIGN AND SETTING: We conducted a prospective cohort study using the Clinical Practice Research Datalink including patients with QRISK scores of 10 to 30 in 2010 to 2013 who were last followed-up in October 2016. Comparing patients with QRISK≥20 and QRISK<20, we explored RDA assumptions, provided proof of concept analyses (total cholesterol as outcome), and investigated the effect of statins prescription on adverse outcomes. RESULT: RDA confirmed statin prescription reduced total cholesterol (Mean difference (MD) -1.33 mmol/L, 95%Confidence Interval (CI) -1.93 to -0.73). RDA provided little evidence for adverse effects on diabetes, myalgia and myositis, liver disease, CVD, or mortality. The RDA analysis findings are similar to RCT results. Findings from non-RDA analysis agree with published observational studies. CONCLUSION: RDA can be used with large routine clinical datasets to provide evidence on effects of medications which are prescribed according to a threshold. Testable RDA assumptions were satisfied, but confidence intervals were wide, partly due to the low compliance with the prescribing threshold

Neurocysticercosis as a first presentation of tonic-clonic seizures: a case report

We report the case of a 28 year-old immigrant Asian man from the Punjab region with a first presentation of seizures. This patient had no significant past medical history, but suffered several headaches in the preceding week and was pyrexial on presentation. A CT scan of his head showed a single area of subcortical low attenuation initially suggesting ischaemia. A lumbar puncture and CSF examination was unremarkable. Further investigation revealed discrete calcified gluteal lesions on pelvic X-ray, and serum immunology positive for cysticercosis. The diagnosis of neurocysticercosis was made, and the patient improved on dexamethasone and a short course of vermicide, to be discharged a week later. With increasing global migration, the prevalence of neurological parasitic infections seen in the UK is likely to rise. This case highlights the importance of careful interpretation of non-specific head CTs in the context of first presentation of seizures in a susceptible population

A conjectural extension of Hecke’s converse theorem

We formulate a precise conjecture that, if true, extends the converse theorem of Hecke without requiring hypotheses on twists by Dirichlet characters or an Euler product. The main idea is to linearize the Euler product, replacing it by twists by Ramanujan sums. We provide evidence for the conjecture, including proofs of some special cases and under various additional hypotheses