708 research outputs found

    Mid-Mesozoic leaves from near Ida Bay, southern Tasmania, Australia

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    Several leaf specimens from a locality in southern Tasmania are described. They are assigned to Coniopteris websterii sp.nov., Cladophlebis indica (Oldham & Morris) Sahni & Rao, Pachypteris sp. cf. indica (Oldham & Morris) Bose & Roy, Otozamites sp., Pterophyllum? sp. and Conites sp. The specimen of Olozamiles sp. is also partially petrified and, thus, gives some indication of its internal tissues. These genera and species suggest a mid-Mesozoic, rather than a Tertiary, age for this locality

    B₂cat₂-Mediated Reduction of Sulfoxides to Sulfides

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    An efficient and operationally simple method for the reduction of sulfoxides to sulfides has been developed using bis(catecholato)diboron (B₂cat₂) as a reducing agent. The present method accommodates various functional groups which are generally prone to reduction: halides, alkynes, carbonyls, nitriles, and heterocycles are totally intact, and only sulfoxide moieties undergo reduction chemoselectively. Moreover, the remaining diboron and the resulting boron‐containing wastes are readily removable, the practicality of this protocol being thus demonstrated

    Integrated engineering environments for large complex products

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    An introduction is given to the Engineering Design Centre at the University of Newcastle upon Tyne, along with a brief explanation of the main focus towards large made-to-order products. Three key areas of research at the Centre, which have evolved as a result of collaboration with industrial partners from various sectors of industry, are identified as (1) decision support and optimisation, (2) design for lifecycle, and (3) design integration and co-ordination. A summary of the unique features of large made-to-order products is then presented, which includes the need for integration and co-ordination technologies. Thus, an overview of the existing integration and co-ordination technologies is presented followed by a brief explanation of research in these areas at the Engineering Design Centre. A more detailed description is then presented regarding the co-ordination aspect of research being conducted at the Engineering Design Centre, in collaboration with the CAD Centre at the University of Strathclyde. Concurrent Engineering is acknowledged as a strategy for improving the design process, however design coordination is viewed as a principal requirement for its successful implementation. That is, design co-ordination is proposed as being the key to a mechanism that is able to maximise and realise any potential opportunity of concurrency. Thus, an agentoriented approach to co-ordination is presented, which incorporates various types of agents responsible for managing their respective activities. The co-ordinated approach, which is implemented within the Design Co-ordination System, includes features such as resource management and monitoring, dynamic scheduling, activity direction, task enactment, and information management. An application of the Design Co-ordination System, in conjunction with a robust concept exploration tool, shows that the computational design analysis involved in evaluating many design concepts can be performed more efficiently through a co-ordinated approach

    Reach and adoption of a Geriatric Emergency Department Accreditation program in the United States

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    STUDY OBJECTIVE: The objectives of this study were to describe the reach and adoption of Geriatric Emergency Department Accreditation (GEDA) program and care processes instituted at accredited geriatric emergency departments (EDs). METHODS: We analyzed a cross-section of a cohort of US EDs that received GEDA from May 2018 to March 2021. We obtained data from the American College of Emergency Physicians and publicly available sources. Data included GEDA level, geographic location, urban/rural designation, and care processes instituted. Frequencies and proportions and median and interquartile ranges were used to summarize categorical and continuous data, respectively. RESULTS: Over the study period, 225 US geriatric ED accreditations were issued and included in our analysis-14 Level 1, 21 Level 2, and 190 Level 3 geriatric EDs; 5 geriatric EDs reapplied and received higher-level accreditation after initial accreditation at a lower level. Only 9 geriatric EDs were in rural regions. There was significant heterogeneity in protocols enacted at geriatric EDs; minimizing urinary catheter use and fall prevention were the most common. CONCLUSION: There has been rapid growth in geriatric EDs, driven by Level 3 accreditation. Most geriatric EDs are in urban areas, indicating the potential need for expansion beyond these areas. Future research evaluating the impact of GEDA on health care utilization and patient-oriented outcomes is needed

    Conformational behavior and electronic structure of silylketenes studied with quantum chemical calculations and photoelectron spectroscopy

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    The He(I) photoelectron spectra of silylketenes (Me3Si)2C=C=O (1), Me5Si2CH=C=O (2), Me2Si(CH=C=O)2 (3), MeSi(CH=C=O)3 (4), (SiMe2CH=C=O)2 (5), and (CH2SiMe2CH=C=O)2 (6) have been recorded and their structures and orbital energies have been calculated by ab initio methods. Orbital energies for disilanes 2 and 5 are strongly dependent on a Si-Si-C-C torsional angle due to σ–π orbital interaction. Comparisons between experimental and simulated spectra show that 2 and 5 prefer conformations in which the Si—Si bond and ketene group(s) are approximately orthogonal (113° and 111°, respectively). Silylalkenes Me5Si2CH=CH2 (7) and (SiMe2CH=CH2)2 (8), which have been included in the computational study, show the same behavior as their corresponding silylketenes. Silylbis- and trisketenes 3–6 do not exhibit π–π interaction of any significance. For Si—Si containing compounds, the best agreement between experimental and computed data was obtained when Becke3LYP/6-31G*//HF/3-21G* was employed

    Structure-activity relationships of pentamidine analogs against Giardia lamblia and correlation of antigiardial activity with DNA-binding affinity.

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    1,5-Di(4-amidinophenoxy)pentane (pentamidine) and 38 analogs of pentamidine were screened for in vitro activity against the enteric protozoan Giardia lamblia WB (ATCC 30957). All compounds were active against G. lamblia as measured by a [methyl-3H]thymidine incorporation assay. Antigiardial activity varied widely, with 50 % inhibitory concentrations (IC50s) ranging from 0.51 ± 0.13 ΌM (mean ± standard deviation) for the most active compound to over 100.0 ΌM for the least active compounds. The IC50of the most potent antigiardial agent.1,5-Di(4-amidinophenoxy)pentane (pentamidine) and 38 analogs of pentamidine were screened for in vitro activity against the enteric protozoan Giardia lamblia WB (ATCC 30957). All compounds were active against G. lamblia as measured by a [methyl-3H]thymidine incorporation assay. Antigiardial activity varied widely, with 50 % inhibitory concentrations (IC50s) ranging from 0.51 ± 0.13 ΌM (mean ± standard deviation) for the most active compound to over 100.0 ΌM for the least active compounds. The IC50of the most potent antigiardial agent

    Dynamic Carboniferous tropical forests: new views of plant function and potential for physiological forcing of climate

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138385/1/nph14700_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138385/2/nph14700.pd

    Primary and secondary metabolism of pentamidine by rats.

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    The antiprotozoal drug pentamidine [1,5-bis(4'-amidinophenoxy)pentane] has been previously shown to be metabolized by rat liver microsomes, and five of the seven putative primary metabolites have been identified. With the synthesis and identification of 5-(4'-amidinophenoxy)pentanoic acid and 5-(4'-amidinophenoxy)-1-pentanol as the remaining two metabolites, the primary metabolism of pentamidine in rats appears fully characterized. Use of [14C]pentamidine with rat liver microsomes confirms this conclusion, since no unidentified radioactive peaks were detected by high-performance liquid chromatography (HPLC). Isolated, perfused rat livers were used with [14C]pentamidine to identify secondary metabolites. Only two novel radioactive peaks were detected by HPLC analysis of perfused liver samples. The treatment of liver samples with sulfatase or beta-glucuronidase resulted in the reduction or elimination of these peaks and gave rise to peaks identified as para-hydroxybenzamidine and 5-(4'-amidinophenoxy)pentanoic acid. It was concluded from these results that only these two primary metabolites were conjugated with sulfate or glucuronic acid. After 4 h of incubation in the perfused liver system, approximately 15% of the recovered radiolabel was pentamidine. These results suggest that pentamidine metabolism can be rapid and extensive in rats

    Finite difference calculations of permeability in large domains in a wide porosity range.

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    Determining effective hydraulic, thermal, mechanical and electrical properties of porous materials by means of classical physical experiments is often time-consuming and expensive. Thus, accurate numerical calculations of material properties are of increasing interest in geophysical, manufacturing, bio-mechanical and environmental applications, among other fields. Characteristic material properties (e.g. intrinsic permeability, thermal conductivity and elastic moduli) depend on morphological details on the porescale such as shape and size of pores and pore throats or cracks. To obtain reliable predictions of these properties it is necessary to perform numerical analyses of sufficiently large unit cells. Such representative volume elements require optimized numerical simulation techniques. Current state-of-the-art simulation tools to calculate effective permeabilities of porous materials are based on various methods, e.g. lattice Boltzmann, finite volumes or explicit jump Stokes methods. All approaches still have limitations in the maximum size of the simulation domain. In response to these deficits of the well-established methods we propose an efficient and reliable numerical method which allows to calculate intrinsic permeabilities directly from voxel-based data obtained from 3D imaging techniques like X-ray microtomography. We present a modelling framework based on a parallel finite differences solver, allowing the calculation of large domains with relative low computing requirements (i.e. desktop computers). The presented method is validated in a diverse selection of materials, obtaining accurate results for a large range of porosities, wider than the ranges previously reported. Ongoing work includes the estimation of other effective properties of porous media
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