60 research outputs found
Subdivision Shell Elements with Anisotropic Growth
A thin shell finite element approach based on Loop's subdivision surfaces is
proposed, capable of dealing with large deformations and anisotropic growth. To
this end, the Kirchhoff-Love theory of thin shells is derived and extended to
allow for arbitrary in-plane growth. The simplicity and computational
efficiency of the subdivision thin shell elements is outstanding, which is
demonstrated on a few standard loading benchmarks. With this powerful tool at
hand, we demonstrate the broad range of possible applications by numerical
solution of several growth scenarios, ranging from the uniform growth of a
sphere, to boundary instabilities induced by large anisotropic growth. Finally,
it is shown that the problem of a slowly and uniformly growing sheet confined
in a fixed hollow sphere is equivalent to the inverse process where a sheet of
fixed size is slowly crumpled in a shrinking hollow sphere in the frictionless,
quasi-static, elastic limit.Comment: 20 pages, 12 figures, 1 tabl
Passive Cooling Technologies for Reducing the Heating of Containers
Containers are widely used within the Bundeswehr, especially in military camps. These containers often overheat, most notably in southern areas. High temperatures can cause problems like accelerated ageing of stored material or failure of electronic equipment running inside. Air conditioning systems can counteract this but consume high amounts of energy and require regular maintenance.
Passive cooling technologies, i.e. technologies that cool without requiring additional energy, are intended to alleviate this problem. The simplest passive cooling technology is shading e.g. by applying additional roofing or camouflage nets. However, the disadvantages are the additional required material and the assembly and disassembly whenever the container is moved.
New technologies for passive cooling are based on different mechanisms: Coatings can reduce the solar heat-up either by being highly reflective or through a novel mechanism called passive daytime radiative cooling (PDRC). Another technique is the use of heat storage panels, which contain phase change material (PCM) to minimize the daytime heating of the containers. Furthermore, spacer fabrics on the surface of containers allow cooling based on the chimney effect.
To evaluate the passive cooling power of the different technologies, containers were equipped with three different cooling coating systems, heat storage panels, spacer fabrics, roofing and camouflage net. Two regular containers were used as a baseline. Temperature was measured at each container at different spots inside and outside. Further, every container was equipped with an air conditioning system and a power meter to measure energy consumption.
All containers with passive cooling technologies showed lower temperatures compared to the reference containers. The power measurements confirmed a lower energy consumption of the air-conditioning systems. PDRC coatings, PCMs und spacer fabrics show a better passive cooling power than shadowing like e.g. roofing. PDRC coatings were the most effective technology overall in this setup, but dependent on the application scenarios, the other passive cooling systems can also be powerful
Factors Associated with the Development of Opportunistic Infections in HIV-1-Infected Adults with High CD4+ Cell Counts: A EuroSIDA Study
BackgroundLimited data exist on factors predicting the development of opportunistic infections (OIs) at higher-than-expected CD4+ cell counts in human immunodeficiency virus (HIV) type 1-infected adults MethodsMultivariate Poisson regression models were used to determine factors related to the development of groups of OIs above their respective traditional upper CD4+ cell count thresholds: group 1 (â©Ÿ100 cells/ÎŒL), OIs caused by cytomegalovirus, Mycobacterium avium complex, and Toxoplasma gondii; group 2 (â©Ÿ200 cells/ÎŒL), Pneumocystis pneumonia and esophageal candidiasis; and group 3 (â©Ÿ300 cells/ÎŒL), pulmonary and extrapulmonary tuberculosis ResultsIn groups 1, 2, and 3, 71 of 9219, 125 of 7934, and 36 of 7838 patients, respectively, developed â©Ÿ1 intragroup OI. The strongest predictor of an OI in groups 1 and 2 was current CD4+ cell count (for group 1, incidence rate ratio [IRR] per 50% lower CD4+ cell count, 5.37 [95% confidence interval {CI}, 3.71-7.77]; for group 2, 4.28 [95% CI, 2.98-6.14]). Injection drug use but not current CD4+ cell count predicted risk in group 3. Use of antiretroviral treatment was associated with a lower incidence of OIs in all groups, likely by reducing HIV-1 RNA levels (IRR per 1-log10 copies/mL higher HIV-1 RNA levels for group 1, 1.50 [95% CI, 1.15-1.95]; for group 2, 1.68 [95% CI, 1.40-2.02]; and for group 3, 1.89 [95% CI, 1.40-2.54]) ConclusionAlthough the absolute incidence is low, the current CD4+ cell count and HIV-1 RNA level are strong predictors of most OIs in patients with high CD4+ cell count
Chemical synthesis and characterization of single-chain C18-chloroparaffin materials with defined degrees of chlorination
Technical chlorinated paraffins (CPs) are produced via radical chlorination of n-alkane feedstocks with different carbon chain-lengths (âŒC10-C30). Short-chain CPs (SCCPs, C10-C13) are classified as persistent organic pollutants (POPs) under the Stockholm Convention. This regulation has induced a shift to use longer-chain CPs as substitutes. Consequently, medium-chain (MCCPs, C14-C17) and long-chain (LCCPs, C>17) CPs have become dominant homologues in recent environmental samples. However, no suitable LCCP-standard materials are available. Herein, we report on the chemical synthesis of single-chain C18-CP-materials, starting with a pure n-alkane and sulfuryl chloride (SO2Cl2). Fractionation of the crude product by normal-phase liquid-chromatography and pooling of suitable fractions yielded in four C18-CP-materials with different chlorination degrees (mCl,EA = 39-52%). In addition, polar side-products, tentatively identified as sulfite-, sulfate- and bis-sulfate-diesters, were separated from CPs. The new single-chain materials were characterized by LC-MS, 1H-NMR and EA. LC-MS provided Relative retention times for different C18-CP homologues and side-products. Mathematical deconvolution of full-scan mass spectra revealed the presence of chloroparaffins (57-93%) and chloroolefins (COs, 7-26%) in the four single-chain C18-CP-materials. Homologue distributions and chlorination degrees were deduced for CPs and COs. 1H-NMR revealed chemical shift ranges of mono-chlorinated (ÎŽÂ = 3.2-5.3 ppm) and non-chlorinated (ÎŽÂ = 1.0-3.2 ppm) hydrocarbon moieties. The synthesized C18-single-chain standard materials and respective spectroscopic data are useful to identify and quantify LCCPs in various materials and environmental samples. CP- and CO-distributions resemble the ones of existing SCCP and MCCP reference materials and technical mixtures. Furthermore, these materials now allow specific studies on the environmental fate and the transformation of long-chain chloroparaffins and chloroolefins
Successful Treatment of Disseminated Acanthamoeba sp. Infection with Miltefosine
We report on an HIV-negative but immunocompromised patient with disseminated acanthamoebiasis, granulomatous amoebic encephalitis, and underlying miliary tuberculosis and tuberculous meningitis. The patient responded favorably to treatment with miltefosine, an alkylphosphocholine. The patient remained well with no signs of infection 2 years after treatment cessation
Susceptibility of adult cat fleas (Siphonaptera: Pulicidae) to insecticides and status of insecticide resistance mutations at the Rdl and knockdown resistance loci
This is an Open Access article. © 2015 The Author(s). Published by Springer Berlin Heidelberg.The susceptibility of 12 field-collected isolates and 4 laboratory strains of cat fleas, Ctenocephalides felis was determined by topical application of some of the insecticides used as on-animal therapies to control them. In the tested field-collected flea isolates the LD50 values for fipronil and imidacloprid ranged from 0.09 to 0.35 ng/flea and 0.02 to 0.19 ng/flea, respectively, and were consistent with baseline figures published previously. The extent of variation in response to four pyrethroid insecticides differed between compounds with the LD50 values for deltamethrin ranging from 2.3 to 28.2 ng/flea, etofenprox ranging from 26.7 to 86.7 ng/flea, permethrin ranging from 17.5 to 85.6 ng/flea, and d-phenothrin ranging from 14.5 to 130 ng/flea. A comparison with earlier data for permethrin and deltamethrin implied a level of pyrethroid resistance in all isolates and strains. LD50 values for tetrachlorvinphos ranged from 20.0 to 420.0 ng/flea. The rdl mutation (conferring target-site resistance to cyclodiene insecticides) was present in most field-collected and laboratory strains, but had no discernible effect on responses to fipronil, which acts on the same receptor protein as cyclodienes. The kdr and skdr mutations conferring target-site resistance to pyrethroids but segregated in opposition to one another, precluding the formation of genotypes homozygous for both mutations.Peer reviewedFinal Published versio
Expression and subcellular localization of USH1C/harmonin in human retina provides insights into pathomechanisms and therapy
Usher syndrome (USH) is the most common form of hereditary deaf-blindness in humans. USH is a complex genetic disorder, assigned to three clinical subtypes differing in onset, course and severity, with USH1 being the most severe. Rodent USH1 models do not reflect the ocular phenotype observed in human patients to date; hence, little is known about the pathophysiology of USH1 in the human eye. One of the USH1 genes, USH1C, exhibits extensive alternative splicing and encodes numerous harmonin protein isoforms that function as scaffolds for organizing the USH interactome. RNA-seq analysis of human retinae uncovered harmonin_a1 as the most abundant transcript of USH1C. Bulk RNA-seq analysis and immunoblotting showed abundant expression of harmonin in MĂŒller glia cells (MGCs) and retinal neurons. Furthermore, harmonin was localized in the terminal endfeet and apical microvilli of MGCs, presynaptic region (pedicle) of cones and outer segments (OS) of rods as well as at adhesive junctions between MGCs and photoreceptor cells (PRCs) in the outer limiting membrane (OLM). Our data provide evidence for the interaction of harmonin with OLM molecules in PRCs and MGCs and rhodopsin in PRCs. Subcellular expression and colocalization of harmonin correlate with the clinical phenotype observed in USH1C patients. We also demonstrate that primary cilia defects in USH1C patient-derived fibroblasts could be reverted by the delivery of harmonin_a1 transcript isoform. Our studies thus provide novel insights into PRC cell biology, USH1C pathophysiology and development of gene therapy treatment(s)
The bii4africa dataset of faunal and floral population intactness estimates across Africa's major land uses
This is the final version. Available on open access from Nature Research via the DOI in this recordCode availability: R code for calculating aggregated intactness scores for a focal region (e.g., ecoregion or country) and/or taxonomic group can be downloaded with the bii4africa dataset on Figshare; see Data Records section.Sub-Saharan Africa is under-represented in global biodiversity datasets, particularly regarding the impact of land use on species' population abundances. Drawing on recent advances in expert elicitation to ensure data consistency, 200 experts were convened using a modified-Delphi process to estimate 'intactness scores': the remaining proportion of an 'intact' reference population of a species group in a particular land use, on a scale from 0 (no remaining individuals) to 1 (same abundance as the reference) and, in rare cases, to 2 (populations that thrive in human-modified landscapes). The resulting bii4africa dataset contains intactness scores representing terrestrial vertebrates (tetrapods: ±5,400 amphibians, reptiles, birds, mammals) and vascular plants (±45,000 forbs, graminoids, trees, shrubs) in sub-Saharan Africa across the region's major land uses (urban, cropland, rangeland, plantation, protected, etc.) and intensities (e.g., large-scale vs smallholder cropland). This dataset was co-produced as part of the Biodiversity Intactness Index for Africa Project. Additional uses include assessing ecosystem condition; rectifying geographic/taxonomic biases in global biodiversity indicators and maps; and informing the Red List of Ecosystems.Jennifer Ward Oppenheimer Research Gran
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The bii4africa dataset of faunal and floral population intactness estimates across Africaâs major land uses
Sub-Saharan Africa is under-represented in global biodiversity datasets, particularly regarding the impact of land use on speciesâ population abundances. Drawing on recent advances in expert elicitation to ensure data consistency, 200 experts were convened using a modified-Delphi process to estimate âintactness scoresâ: the remaining proportion of an âintactâ reference population of a species group in a particular land use, on a scale from 0 (no remaining individuals) to 1 (same abundance as the reference) and, in rare cases, to 2 (populations that thrive in human-modified landscapes). The resulting bii4africa dataset contains intactness scores representing terrestrial vertebrates (tetrapods: ±5,400 amphibians, reptiles, birds, mammals) and vascular plants (±45,000 forbs, graminoids, trees, shrubs) in sub-Saharan Africa across the regionâs major land uses (urban, cropland, rangeland, plantation, protected, etc.) and intensities (e.g., large-scale vs smallholder cropland). This dataset was co-produced as part of the Biodiversity Intactness Index for Africa Project. Additional uses include assessing ecosystem condition; rectifying geographic/ taxonomic biases in global biodiversity indicators and maps; and informing the Red List of Ecosystems
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