2,626 research outputs found

    Tuning gastropod locomotion: Modeling the influence of mucus rheology on the cost of crawling

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    Common gastropods such as snails crawl on a solid substrate by propagating muscular waves of shear stress on a viscoelastic mucus. Producing the mucus accounts for the largest component in the gastropod's energy budget, more than twenty times the amount of mechanical work used in crawling. Using a simple mechanical model, we show that the shear-thinning properties of the mucus favor a decrease in the amount of mucus necessary for crawling, thereby decreasing the overall energetic cost of locomotion.Comment: Corrected typo

    Enhanced aging properties of HKUST-1 in hydrophobic mixed-matrix membranes for ammonia adsorption.

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    Metal-organic frameworks (MOFs) in their free powder form have exhibited superior capacities for many gases when compared to other materials, due to their tailorable functionality and high surface areas. Specifically, the MOF HKUST-1 binds small Lewis bases, such as ammonia, with its coordinatively unsaturated copper sites. We describe here the use of HKUST-1 in mixed-matrix membranes (MMMs) prepared from polyvinylidene difluoride (PVDF) for the removal of ammonia gas. These MMMs exhibit ammonia capacities similar to their hypothetical capacities based on the weight percent of HKUST-1 in each MMM. HKUST-1 in its powder form is unstable toward humid conditions; however, upon exposure to humid environments for prolonged periods of time, the HKUST-1 MMMs exhibit outstanding structural stability, and maintain their ammonia capacity. Overall, this study has achieved all of the critical and combined elements for real-world applications of MOFs: high MOF loadings, fully accessible MOF surfaces, enhanced MOF stabilization, recyclability, mechanical stability, and processability. This study is a critical step in advancing MOFs to a stable, usable, and enabling technology

    Fuel Consumption of a Carburetor Engine at Various Speeds and Torques

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    An investigation was conducted to obtain fuel-consumption curves for a single-cylinder engine with a Wright 1820-G and Pratt & Whitney 1340-H cylinder at varying speeds, manifold pressures, and air-fuel ratios. The 1340- H cylinder was tested at speeds from 1,200 to 2,400 r.p.m. and at manifold pressures from 21 to 38 inches of mercury absolute. Less than extensive tests were made of the 1820-G cylinder. The results of the tests showed that the minimum brake fuel consumption was obtained when the engines were operating at high torques and at speeds from 60 to 70 percent of the rated speed. The fuel consumption increased at an increasing rate as the torque was reduced; and, at 45 percent of maximum torque, the fuel consumption was 20 percent higher than at maximum torque when the engines were operating at 70 percent of rated speed. Minimum specific fuel consumption was obtained at the same air-fuel ratio regardless of compression ratio. No improvement in fuel consumption was obtained when mixtures leaner than an air-fuel ratio of 15.5 were used. The leanest mixture ratio on which the engine with the 1340-H cylinder would operate smoothly was 18.5 and the spark advance for maximum power with this mixture ratio was 50 degrees B.T.C. A method is discussed for reducing the amount of testing necessary to obtain curves for minimum brake fuel consumption

    Comparative Performance of Engines Using a Carburetor, Manifold Injection, and Cylinder Injection

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    The comparative performance was determined of engines using three methods of mixing the fuel and the air: the use of a carburetor, manifold injection, and cylinder injection. The tests were made of a single-cylinder engine with a Wright 1820-G air-cooled cylinder. Each method of mixing the fuel and the air was investigated over a range of fuel-air ratios from 0.10 to the limit of stable operation and at engine speeds of 1,500 and 1,900 r.p.m. The comparative performance with a fuel-air ratio of 0.08 was investigated for speeds from 1,300 to 1,900 r.p.m. The results show that the power obtained with each method closely followed the volumetric efficiency; the power was therefore the highest with cylinder injection because this method had less manifold restriction. The values of minimum specific fuel consumption obtained with each method of mixing of fuel and air were the same. For the same engine and cooling conditions, the cylinder temperatures are the same regardless of the method used for mixing the fuel and the air

    Differential localization and expression of complement in a rat model of motor neuron disease

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    ComBio is the major ASBMB conference held each year, in association with other organisations. This page has links to past, current and future ComBio meetings. Further information and links will be placed online as they become available

    PELATIHAN PENGELOLAAN DOI BAGI EDITOR JURNAL POLITEKNIK PERKAPALAN NEGERI SURABAYA

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      Perguruan tinggi memiliki tugas yang tertuang dalam Tridharma Perguruan Tinggi. Aspek pendidikan, penelitian dan pengabdian kepada masyarakat merupakan aspek-aspek yang termaktub dalam Tridharma Perguruan Tinggi. Hasil kegiatan penelitian dan pengabdian masyarakat harus didukung oleh Digital Object Identifier yang aktif dan terpublikasi. Pengelolaan Digital Object Identifier belum dijalankan secara maksimal di Politeknik Perkapalan Negeri Surabaya. Hal ini mendorong inisiasi suatu kegiatan guna menunjang aspek tersebut. Pelatihan pengelolaan Digital Object Identifier menjadi salah satu solusi yang ditawarkan guna meningkatkan pemahaman dan pengetahuan mengenai pengelolaan Digital Object Identifier. Pelatihan diikuti oleh pengelola jurnal dibawah naungan Politeknik Perkapalan Negeri Surabaya. Luaran dari kegiatan ini menunjukan bahwa editor jurnal dibawah naungan Politeknik Perkapalan Negeri Surabaya berhasil dalam mempublikasikan Digital Object Identifier. Hal tersebut dapat meningkatkan dan mengoptimalkan kinerja artikel ilmiah yang mendukung proses akreditasi jurnal di Indonesia

    On the Prediction of Extreme Ecological Events

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    Ecological studies often focus on average effects of environmental factors, but ecological dynamics may depend as much upon environmental extremes. Ecology would therefore benefit from the ability to predict the frequency and severity of extreme environmental events. Some extreme events (e.g., earthquakes) are simple events: either they happen or they don\u27t, and they are generally difficult to predict. In contrast, extreme ecological events are often compound events, resulting from the chance coincidence of run-of-the-mill factors. Here we present an environmental bootstrap method for resampling short-term environmental data (rolling the environmental dice) to calculate an ensemble of hypothetical time series that embodies how the physical environment could potentially play out differently. We use this ensemble in conjunction with mechanistic models of physiological processes to analyze the biological consequences of environmental extremes. Our resampling method provides details of these consequences that would be difficult to obtain otherwise, and our methodology can be applied to a wide variety of ecological systems. Here, we apply this approach to calculate return times for extreme hydrodynamic and thermal events on intertidal rocky shores. Our results demonstrate that the co-occurrence of normal events can indeed lead to environmental extremes, and that these extremes can cause disturbance. For example, the limpet Lottia gigantea and the mussel Mytilus californianus are co-dominant competitors for space on wave-swept rocky shores, but their response to extreme environmental events differ. Limpet mortality can vary drastically through time. Average yearly maximum body temperature of L. gigantea on horizontal surfaces is low, sufficient to kill fewer than 5% of individuals, but on rare occasions environmental factors align by chance to induce temperatures sufficient to kill \u3e99% of limpets. In contrast, mussels do not exhibit large temporal variation in the physical disturbance caused by breaking waves, and this difference in the pattern of disturbance may have ecological consequences for these competing species. The effect of environmental extremes is under added scrutiny as the frequency of extreme events increases in response to anthropogenically forced climate change. Our method can be used to discriminate between chance events and those caused by long-term shifts in climate

    Appropriateness of antibiotic prescribing in the Emergency Department

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    Background Antibiotics are some of the most commonly prescribed drugs in the Emergency Department (ED) and yet data describing the overall appropriateness of antibiotic prescribing in the ED is scarce. Objectives To describe the appropriateness of antibiotic prescribing in the ED. Methods A retrospective, observational study of current practice. All patients who presented to the ED during the study period and were prescribed at least one antibiotic were included. Specialists from Infectious Disease, Microbiology and Emergency Medicine and a Senior Pharmacist assessed antibiotic appropriateness against evidence-based guidelines. Results A total of 1019 (13.6%) of patient presentations involved the prescription of at least one antibiotic. Of these, 640 (62.8%) antibiotic prescriptions were assessed as appropriate, 333 (32.7%) were assessed as inappropriate and 46 (4.5%) were deemed to be not assessable. Adults were more likely to receive an inappropriate antibiotic prescription than children (36.9% versus 22.9%; difference 14.1%, 95% CI 7.2%–21.0%). Patients who met quick Sepsis-related Organ Failure Assessment (qSOFA) criteria were more likely to be prescribed inappropriate antibiotics (56.7% versus 36.1%; difference 20.5%, 95% CI, 2.4%–38.7%). There was no difference in the incidence of appropriate antibiotic prescribing based on patient gender, disposition (admitted/discharged), reason for antibiotic administration (treatment/prophylaxis) or time of shift (day/night). Conclusions Inappropriate administration of antibiotics can lead to unnecessary adverse events, treatment failure and antimicrobial resistance. With over one in three antibiotic prescriptions in the ED being assessed as inappropriate, there is a pressing need to develop initiatives to improve antibiotic prescribing to prevent antibiotic-associated patient and community harms.No Full Tex
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