2,675 research outputs found

    Microprocessor-based insulin delivery device with amperometric glucose sensing

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    This paper details the design of a closed-loop insulin delivery device, consisting of a glucose sensing circuit, and a basic microprocessor-based syringe pump. The glucose sensing circuit contains the required components to interface with CGMS\u27s glucose sensor assembly, while the syringe pump design uses microprocessor to allow flexible control over the pump driver. Instrumentation developed in this paper provides a ready reference to other researchers on the construction of a closed-loop insulin delivery apparatus with amperometric glucose sensor.<br /

    The effects of vortex modeling on blade-vortex interaction noise prediction

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    The use of a blade vortex interaction noise prediction scheme, based on CAMRAD/JA, FPR and RAPP, quantifies the effects of errors and assumptions in the modeling of the helicopter's shed vortex on the acoustic predictions. CAMRAD/JA computes the wake geometry and inflow angles that are used in FPR to solve for the aerodynamic surface pressures. RAPP uses these surface pressures to predict the acoustic pressure. Both CAMRAD/JA and FPR utilize the Biot-Savart Law to determine the influence of the vortical velocities on the blade loading and both codes use an algebraic vortex model for the solid body rotation of the vortex core. Large changes in the specification of the vortex core size do not change the inplane wake geometry calculated by CAMRAD/JA and only slightly affect the out-of-plane wake geometry. However, the aerodynamic surface pressure calculated by FPR changes in both magnitude and character with small changes to the core size used by the FPR calculations. This in turn affects the acoustic predictions. Shifting the CAMRAD/JA wake geometry away from the rotor plane by 1/4 chord produces drastic changes in the acoustic predictions indicating that the prediction of acoustic pressure is extremely sensitive to the miss distance between the vortex and the blade and that this distance must be calculated as accurately as possible for acceptable noise predictions. The inclusion or exclusion of a vortex in the FPR-RAPP calculation allows for the determination of the relative importance of that vortex as a BVI noise source

    Medicinal properties of Plantago major: hypoglycaemic and male fertility studies

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    Plantago major extract has been traditionally used for treating diabetes and to increase male fertility. This study was conducted to verify its efficacy. The hypoglycaemic property of P. major aqueous leaf extract was determined 1Yy oral administration of four treatment doses (l00, 200, 400 and 600 mg/kg body weight). Saline and glibenclamide were used as controls. Glucose Tolerance Test was done at -10, 0, 5, 15, 30, 60, 90, 120 and 180 minutes and the plasma glucose concentration was determined 1Yy the glucose oxidase assay. The study showed that only the 600 mg/kg dose had a significant effect in reducing blood glucose level in diabetic rats. However, the effect of the aqueous extracts was less pronounced compared to glibenclamide. In the fertility study, an aqueous extract from P. major seeds was given orally to rats at 30, 60, 100 and 200 mg/kg body weight respectively. The effect of each dose on vas deferens sperm concentrations after 20 days of treatment was determined. Analysis of the data showed significant increases in sperm concentrations in the 60, 100 and 200 mg/kg body weight groups. However, the trend in increased testosterone levels from day 8 to 14 in the 60 and 200 mg/kg groups was insignificant, suggestive of other factors, possibly antiestrogens in the seed extract contributing to the spermatogenic effect. The studies suggest that aqueous extract from P. major could contain chemicals for treating diabetes mellitus and male infertility problems

    Comparison of engagement and emotional responses of older and younger adults interacting with 3D cultural heritage artefacts on personal devices

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    The availability of advanced software and less expensive hardware allows museums to preserve and share artefacts digitally. As a result, museums are frequently making their collections accessible online as interactive, 3D models. This could lead to the unique situation of viewing the digital artefact before the physical artefact. Experiencing artefacts digitally outside of the museum on personal devices may affect the user's ability to emotionally connect to the artefacts. This study examines how two target populations of young adults (18–21 years) and the elderly (65 years and older) responded to seeing cultural heritage artefacts in three different modalities: augmented reality on a tablet, 3D models on a laptop, and then physical artefacts. Specifically, the time spent, enjoyment, and emotional responses were analysed. Results revealed that regardless of age, the digital modalities were enjoyable and encouraged emotional responses. Seeing the physical artefacts after the digital ones did not lessen their enjoyment or emotions felt. These findings aim to provide an insight into the effectiveness of 3D artefacts viewed on personal devices and artefacts shown outside of the museum for encouraging emotional responses from older and younger people

    Hamiltonian and Linear-Space Structure for Damped Oscillators: I. General Theory

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    The phase space of NN damped linear oscillators is endowed with a bilinear map under which the evolution operator is symmetric. This analog of self-adjointness allows properties familiar from conservative systems to be recovered, e.g., eigenvectors are "orthogonal" under the bilinear map and obey sum rules, initial-value problems are readily solved and perturbation theory applies to the_complex_ eigenvalues. These concepts are conveniently represented in a biorthogonal basis.Comment: REVTeX4, 10pp., 1 PS figure. N.B.: `Alec' is my first name, `Maassen van den Brink' my family name. v2: extensive streamlinin

    Bimetallic non-alloyed NPs for improving the broadband optical absorption of thin amorphous silicon substrates

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    We propose the use of bimetallic non-alloyed nanoparticles (BNNPs) to improve the broadband optical absorption of thin amorphous silicon substrates. Isolated bimetallic NPs with uniform size distribution on glass and silicon are obtained by depositing a 10-nm Au film and annealing it at 600°C; this is followed by an 8-nm Ag film annealed at 400°C. We experimentally demonstrate that the deposition of gold (Au)-silver (Ag) bimetallic non-alloyed NPs (BNNPs) on a thin amorphous silicon (a-Si) film increases the film\u27s average absorption and forward scattering over a broad spectrum, thus significantly reducing its total reflection performance. Experimental results show that Au-Ag BNNPs fabricated on a glass substrate exhibit resonant peaks at 437 and 540 nm and a 14-fold increase in average forward scattering over the wavelength range of 300 to 1,100 nm in comparison with bare glass. When deposited on a 100-nmthin a-Si film, Au-Ag BNNPs increase the average absorption and forward scattering by 19.6% and 95.9% compared to those values for Au NPs on thin a-Si and plain a-Si without MNPs, respectively, over the 300- to 1,100-nm range

    Eigenvector Expansion and Petermann Factor for Ohmically Damped Oscillators

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    Correlation functions C(t)C(t) \sim in ohmically damped systems such as coupled harmonic oscillators or optical resonators can be expressed as a single sum over modes jj (which are not power-orthogonal), with each term multiplied by the Petermann factor (PF) CjC_j, leading to "excess noise" when Cj>1|C_j| > 1. It is shown that Cj>1|C_j| > 1 is common rather than exceptional, that Cj|C_j| can be large even for weak damping, and that the PF appears in other processes as well: for example, a time-independent perturbation \sim\ep leads to a frequency shift \sim \ep C_j. The coalescence of JJ (>1>1) eigenvectors gives rise to a critical point, which exhibits "giant excess noise" (CjC_j \to \infty). At critical points, the divergent parts of JJ contributions to C(t)C(t) cancel, while time-independent perturbations lead to non-analytic shifts \sim \ep^{1/J}.Comment: REVTeX4, 14 pages, 4 figures. v2: final, 20 single-col. pages, 2 figures. Streamlined with emphasis on physics over formalism; rewrote Section V E so that it refers to time-dependent (instead of non-equilibrium) effect

    Parents’ Perceptions of the Physical Health Outcomes of Young People Diagnosed with First Episode Psychosis

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    This study explores parents’ perceptions of their son/daughter’s physical health needs following a first episode psychosis diagnosis and commencement on antipsychotic medication. The research process was guided by grounded theory methodology and data were collected using semi-structure interviews with 16 parents. Four categories were identified. Participants described the importance, challenges and strategies for their son/daughter to maintain their physical health, and the need to improve young people’s health literacy, particularly in areas of physical health, diet and lifestyle. These findings will assist health professionals to provide parents with information to better support their son/daughter to maintain their physical health
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