Miniature reciprocating heat pumps and engines

The present invention discloses a miniature thermodynamic device that can be constructed using standard micro-fabrication techniques. The device can be used to provide cooling, generate power, compress gases, pump fluids and reduce pressure below ambient (operate as a vacuum pump). Embodiments of the invention relating to the production of a cooling effect and the generation of electrical power, change the thermodynamic state of the system by extracting energy from a pressurized fluid. Energy extraction is attained using an expansion process, which is as nearly isentropic as possible for the appropriately chosen fluid. An isentropic expansion occurs when a compressed gas does work to expand, and in the disclosed embodiments, the gas does work by overcoming either an electrostatic or a magnetic force

Adverse Drug Reactions in Hospitalised Children

Adverse Drug Reactions (ADRs) are a global health problem and a leading cause of death, illness and injury in economically developed countries. Therapeutic response, as well the occurrence of undesired effects, can differ significantly between children and adults and many drugs have not been sufficiently studied in the paediatric population. Existing studies on ADRs in children differ widely in study design and outcome reporting, and many are methodically problematic. The incidence and characteristics of ADRs in hospitalised children and factors associated with an increased risk of experiencing and ADR, were assessed in a large, prospective, observational study. 17.7% of all children experienced at least one ADR. Opiate analgesia and drugs used in general anaesthesia (GA) accounted for more than 50% of all drugs implicated in ADRs. Less than 1% of ADRs caused permanent harm or required admission to a higher level of care. Children post GA were more than six times more likely to experience an ADR than children who had not received a GA (HR 6.38; 95%CI 5.3-7.7). Other risk factors identified were increasing age (HR 1.05 for each year; 95%CI 1.04-1.07), increasing number of medicines (HR 1.25 for each additional medicine; 95%CI 1.22-1.28) and being an oncology patient (HR 1.89; 95%CI 1.36-2.63). The proportion of ADRs caused by GA agents and opiate analgesia has previously been underestimated. The cost of excess bed days due to ADRs, has been estimated to be £2 Million per year for a 400-bed adult hospital. The cost of excess bed days in our study was only £35,000 per year for a 300-bed hospital. Other parameters and methods might need to be considered when assessing the financial impact of ADRs in children. Cisplatin is used in cancer treatment and causes irreversible hearing loss in 42-88% of children. Cathechol-O-Methyltransferase (COMT) and Thiopurine-S-Methyltransferase (TPMT) genetic variants have been associated with hearing loss in paediatric patients, but findings from subsequent studies are contradictory. The occurrence of COMT and TPMT genetic variants in a UK population was examined in a retrospective, multicentre cohort study. Known risk factors for ototoxicity were confirmed; increasing cumulative dose of cisplatin younger age (p< 0.01), cranial radiotherapy (p <0.028) and exposure to vincristine p< 0.091). The association with COMT and TPMT genetic polymorphisms could not be replicated. ADRs in children are common and improving medicines safety in children remains a vital aspect of clinical care. New assessment tools are aiming to address some of the challenges faced by clinicians and researchers. Our knowledge of pharmacokinetics and pharmacodynamics in children is still limited, but advances in the field of paediatric pharmacogenomics are beginning to translate into improved medicines safety and efficacy for children. Further work about non-Oncology ADRs would benefit from a focus on high impact events that are described in this thesis

Imaging ellipsometry of graphene

Imaging ellipsometry studies of graphene on SiO2/Si and crystalline GaAs are presented. We demonstrate that imaging ellipsometry is a powerful tool to detect and characterize graphene on any flat substrate. Variable angle spectroscopic ellipsometry is used to explore the dispersion of the optical constants of graphene in the visible range with high lateral resolution. In this way the influence of the substrate on graphene's optical properties can be investigatedComment: 3 pages, 3 figure

Identifying rainfall-runoff events in discharge time series: a data-driven method based on information theory

In this study, we propose a data-driven approach for automatically identifying rainfall-runoff events in discharge time series. The core of the concept is to construct and apply discrete multivariate probability distributions to obtain probabilistic predictions of each time step that is part of an event. The approach permits any data to serve as predictors, and it is non-parametric in the sense that it can handle any kind of relation between the predictor(s) and the target. Each choice of a particular predictor data set is equivalent to formulating a model hypothesis. Among competing models, the best is found by comparing their predictive power in a training data set with user-classified events. For evaluation, we use measures from information theory such as Shannon entropy and conditional entropy to select the best predictors and models and, additionally, measure the risk of overfitting via cross entropy and Kullback–Leibler divergence. As all these measures are expressed in “bit”, we can combine them to identify models with the best tradeoff between predictive power and robustness given the available data. We applied the method to data from the Dornbirner Ach catchment in Austria, distinguishing three different model types: models relying on discharge data, models using both discharge and precipitation data, and recursive models, i.e., models using their own predictions of a previous time step as an additional predictor. In the case study, the additional use of precipitation reduced predictive uncertainty only by a small amount, likely because the information provided by precipitation is already contained in the discharge data. More generally, we found that the robustness of a model quickly dropped with the increase in the number of predictors used (an effect well known as the curse of dimensionality) such that, in the end, the best model was a recursive one applying four predictors (three standard and one recursive): discharge from two distinct time steps, the relative magnitude of discharge compared with all discharge values in a surrounding 65&thinsp;h time window and event predictions from the previous time step. Applying the model reduced the uncertainty in event classification by 77.8&thinsp;%, decreasing conditional entropy from 0.516 to 0.114 bits. To assess the quality of the proposed method, its results were binarized and validated through a holdout method and then compared to a physically based approach. The comparison showed similar behavior of both models (both with accuracy near 90&thinsp;%), and the cross-validation reinforced the quality of the proposed model. Given enough data to build data-driven models, their potential lies in the way they learn and exploit relations between data unconstrained by functional or parametric assumptions and choices. And, beyond that, the use of these models to reproduce a hydrologist's way of identifying rainfall-runoff events is just one of many potential applications.</p

Skeletopy of the intumescentia lumbalis and conus medullaris applied to epidural anaesthesia in Leopardus geoffroyi

Background: Leopardus geoffroyi is a Neotropical wild felid with wide distribution in the south of the South American continent. The objective was to investigate the skeletopy of the intumescentia lumbalis (IL) and conus medullaris (CM) from 11 specimens of L. geoffroyi collected dead on highways. Materials and methods: The cadavers were fixed in formaldehyde solution and dissected to allow the dorsal exposure of IL and CM. The cranial and caudal limits were marked with radiopaque pins and radiographic projections were used to determine the skeletopy. The lengths of IL and CM were measured with a pachymeter. Results: In most specimens, the IL was located at the level of L4 and L5 vertebrae, although in 4 (1 male and 3 females) individuals its cranial limit was L3 and in 3 specimens (2 male and 1 female) the caudal limit was L6. The length of IL was 35.6 ± 6.7 mm. The CM had its base predominantly at the level of the L5 vertebra, although in some specimens the base was in L4 and in others in L6. The apex of the CM can be found since the lumbosacral junction until the level of the Cd2 vertebra. The CM measured 74.4 ± 14.3 mm. Conclusions: Based on the skeletopy, it can be suggested that epidural anaesthesia procedures in L. geoffroyi are safer with the introduction of the catheter through the sacrocaudal interarcual space, as recommended by some anaesthetists for the domestic cat

Adverse drug reactions and off-label and unlicensed medicines in children: a nested case control study of inpatients in a pediatric hospital

Off-label and unlicensed (OLUL) prescribing has been prevalent in pediatric practice. Using data from a prospective cohort study of adverse drug reactions (ADRs) among pediatric inpatients, we aimed to test the hypothesis that OLUL status is a risk factor for ADRs

Mirror Symmetry, Mirror Map and Applications to Calabi-Yau Hypersurfaces

Mirror Symmetry, Picard-Fuchs equations and instanton corrected Yukawa couplings are discussed within the framework of toric geometry. It allows to establish mirror symmetry of Calabi-Yau spaces for which the mirror manifold had been unavailable in previous constructions. Mirror maps and Yukawa couplings are explicitly given for several examples with two and three moduli.Comment: 59 pages. Some changes in the references, a few minor points have been clarifie