154 research outputs found

    B-site substituted lanthanum strontium ferrites as electrode materials for electrochemical applications

    Get PDF
    For electrochemical systems such as solid oxide fuel cells (SOFCs) or solid oxide electrolyzer cells (SOECs), perovskites are widely used as cathode material for the reduction of molecular oxygen. At present, strontium-substituted lanthanum manganite, La1-xSrxMnO3-δ (LSM), is used as standard SOFC cathode material for operation at high temperatures, whereas strontium-substituted lanthanum ferrite (LSF) is alternatively explored for medium-temperature SOFCs. Moreover, LSF is considered to be a potential candidate for oxygen separation membranes as the material reported interesting electrical properties. The design of new perovskite-type La transition-metal oxides is of significant technological importance in order to reduce the operating temperature to 600-800 °C and thus to reduce the SOFC system cost. For investigations on a new material class, (La1-xSrx)yFe1-z(Ni,Cu)zO3-δ was synthesized by a spray-pyrolysis process and modified on the A-site in both stoichiometric and non-stoichiometric configurations and on the B-site by substituting Fe with Ni and C

    Prophylactic titanium elastic nailing (TEN) following femoral lengthening (Lengthening then rodding) with one or two nails reduces the risk for secondary interventions after regenerate fractures: a cohort study in monolateral vs. bilateral lengthening procedures

    Full text link
    Background: Femoral fracture rates of up to 30% have been reported following lengthening procedures using fixators. “Lengthening then rodding” uses one or two titanium elastic nails (TENs) for prophylactic intramedullary nailing to reduce this complication. The aim of the study was to decide if usage of only one TEN is safe or has it a higher risk of getting a fracture? And we asked if there is a difference between patients with monolateral or bilateral lengthening procedures according to their fracture rate? Methods: One or two TENs were implanted in two groups of patients (monolateral and bilateral) after femoral lengthening procedures. The regenerate quality was classified using the Li system and fractures were categorized using the Simpson and Kenwright classification. The follow-up period was at least 1 year after removal of the frame. Results: Sixty-seven patients with 101 femoral lengthening procedures were included in 2007–2011. Group A included 34 patients with bilateral lengthening due to congenital short stature. Group B consisted of 33 patients with congenital disorders with leg length discrepancies. Seven fractures in six patients were seen in group A and five fractures in group B. One patient had residual shortening of 1 cm, and 11 fractures healed without relevant deviation (< 5°) or shortening (< 5 mm). A soft-tissue infection in one patient led to early removal of one TEN. Conclusions: Fractures occurred in both groups of patients in total in 12 of the 101 cases (12%). The rate of secondary interventions was markedly reduced. Usage of one or two TENs did not influence the fracture rate.<br

    Tofacitinib Loaded Squalenyl Nanoparticles for Targeted Follicular Delivery in Inflammatory Skin Diseases

    Get PDF
    Tofacitinib (TFB), a Janus kinase inhibitor, has shown excellent success off-label in treating various dermatological diseases, especially alopecia areata (AA). However, TFB’s safe and targeted delivery into hair follicles (HFs) is highly desirable due to its systemic adverse effects. Nanoparticles (NPs) can enhance targeted follicular drug delivery and minimize interfollicular permeation and thereby reduce systemic drug exposure. In this study, we report a facile method to assemble the stable and uniform 240 nm TFB loaded squalenyl derivative (SqD) nanoparticles (TFB SqD NPs) in aqueous solution, which allowed an excellent loading capacity (LC) of 20%. The SqD NPs showed an enhanced TFB delivery into HFs compared to the aqueous formulations of plain drug in an ex vivo pig ear model. Furthermore, the therapeutic efficacy of the TFB SqD NPs was studied in a mouse model of allergic dermatitis by ear swelling reduction and compared to TFB dissolved in a non-aqueous mixture of acetone and DMSO (7:1 v/v). Whereas such formulation would not be acceptable for use in the clinic, the TFB SqD NPs dispersed in water illustrated a better reduction in inflammatory effects than plain TFB’s aqueous formulation, implying both encouraging good in vivo efficacy and safety. These findings support the potential of TFB SqD NPs for developing a long-term topical therapy of AA

    Three-dimensional pore structure and ion conductivity of porous ceramic diaphragms

    Get PDF
    The ion conductivity of two series of porous ceramic diaphragms impregnated with caustic potash was investigated by electrochemical impedance spectroscopy. To understand the impact of the pore structure on ion conductivity, the three-dimensional (3-D) pore geometry of the diaphragms was characterized with synchrotron x-ray absorption tomography. Ion migration was calculated based on an extended pore structure model, which includes the electrolyte conductivity and geometric pore parameters, for example, tortuosity (τ) and constriction factor (β), but no fitting parameters. The calculated ion conductivities are in agreement with the data obtained from electrochemical measurements on the diaphragms. The geometric tortuosity was found to be nearly independent of porosity. Pore path constrictions diminish with increasing porosity. The lower constrictivity provides more pore space that can effectively be used for mass transport. Direct measurements from tomographs of tortuosity and constrictivity opens new possibilities to study pore structures and transport properties of porous materials

    The benzene polycarboxylic acid (BPCA) pattern of wood pyrolyzed between 200°C and 1000°C

    Full text link
    Environmental charcoals represent a poorly defined part of the black carbon (BC) combustion continuum and may differ widely in their chemical and physical properties, depending on combustion conditions and source material. The benzene polycarboxylic acid (BPCA) molecular marker method is well established to quantify the BC component in charcoal, soil and sediment, although observed variations between labs could stem from subtle differences in methods. The objectives of this study were to identify and improve potential sources of analytical uncertainty. The improved method was then used to qualitatively characterize wood charred at 200–1000 °C. One significant improvement of the BPCA method was to replace citric acid with phthalic acid as an internal standard, which is more stable in acidic solution and more similar to the target compounds. Also, including a soil reference material as a quality control in each analysis proved to be a robust tool to detect for variations in reproducibility. For the thermosequence, elemental O/C and H/C ratios typically decreased with temperature to 60.03 at 1000 °C, whereas BPCA concentrations peaked at 700 °C. With temperature B6CA proportions increased consistently (6–98%), except for a plateau at 250–500 °C. Thus, relative contributions of B6CA reflected the pyrolysis temperature and probably also the degree of condensation of the charcoals we investigated. Future work will show if our results can be directly related to charcoal produced under oxygen limited conditions, including charcoal formed at wildfires or so called biochar for agricultural use

    Physics Opportunities of a Fixed-Target Experiment using the LHC Beams

    Full text link
    We outline the many physics opportunities offered by a multi-purpose fixed-target experiment using the LHC proton and Pb beams extracted by a bent crystal. In a proton run with the LHC 7-TeV beam, one can analyze pp, pd and pA collisions at sqrt(s_NN)~115 GeV and even higher using the Fermi motion in a nuclear target. In a Pb run with a 2.76 TeV-per-nucleon beam, sqrt(s_NN) is as high as 72 GeV. Bent crystals can be used to extract about 5x10^8 protons/s; the integrated luminosity over a year reaches 0.5fb-1 on a typical 1 cm-long target without species limitation. Such an extraction mode does not alter the performance of the collider experiments at the LHC. By instrumenting the target-rapidity region, gluon and heavy-quark proton and neutron PDFs can be accessed at large x and even at x larger than 1 in the nuclear case. Single diffractive physics and, for the first time, the large negative-xF domain can be accessed. The nuclear target-species versatility provides a unique opportunity to study nuclear matter vs. the features of the hot and dense matter formed in heavy-ion collisions, which can be studied in PbA collisions over the full range of target-rapidity domain with a large variety of nuclei. The polarization of hydrogen and nuclear targets allows an ambitious spin program, including measurements of the QCD lensing effects which underlie the Sivers single-spin asymmetry, the study of transversity distributions and possibly of polarized PDFs. We also emphasize the potential offered by pA ultra-peripheral collisions where the nucleus target A is used as a coherent photon source, mimicking photoproduction processes in ep collisions. Finally, we note that W and Z bosons can be produced and detected in a fixed-target experiment and in their threshold domain for the first time, providing new ways to probe the partonic content of the proton and the nucleus.Comment: 14 pages, 2 figures, 5 tables. Comments are welcom

    A benzene-degrading nitrate-reducing microbial consortium displays aerobic and anaerobic benzene degradation pathways

    Get PDF
    All sequence data from this study were deposited at the European Bioinformatics Institute under the accession numbers ERS1670018 to ERS1670023. Further, all assigned genes, taxonomy, function, sequences of contigs, genes and proteins can be found in Table S3.In this study, we report transcription of genes involved in aerobic and anaerobic benzene degradation pathways in a benzene-degrading denitrifying continuous culture. Transcripts associated with the family Peptococcaceae dominated all samples (2136% relative abundance) indicating their key role in the community. We found a highly transcribed gene cluster encoding a presumed anaerobic benzene carboxylase (AbcA and AbcD) and a benzoate-coenzyme A ligase (BzlA). Predicted gene products showed >96% amino acid identity and similar gene order to the corresponding benzene degradation gene cluster described previously, providing further evidence for anaerobic benzene activation via carboxylation. For subsequent benzoyl-CoA dearomatization, bam-like genes analogous to the ones found in other strict anaerobes were transcribed, whereas gene transcripts involved in downstream benzoyl-CoA degradation were mostly analogous to the ones described in facultative anaerobes. The concurrent transcription of genes encoding enzymes involved in oxygenase-mediated aerobic benzene degradation suggested oxygen presence in the culture, possibly formed via a recently identified nitric oxide dismutase (Nod). Although we were unable to detect transcription of Nod-encoding genes, addition of nitrite and formate to the continuous culture showed indication for oxygen production. Such an oxygen production would enable aerobic microbes to thrive in oxygen-depleted and nitrate-containing subsurface environments contaminated with hydrocarbons.This study was supported by a grant of BE-Basic-FES funds from the Dutch Ministry of Economic Affairs. The research of A.J.M. Stams is supported by an ERC grant (project 323009) and the gravitation grant “Microbes for Health and Environment” (project 024.002.002) of the Netherlands Ministry of Education, Culture and Science. F. Hugenholtz was supported by the same gravitation grant (project 024.002.002). B. Hornung is supported by Wageningen University and the Wageningen Institute for Environment and Climate Research (WIMEK) through the IP/OP program Systems Biology (project KB-17-003.02-023).info:eu-repo/semantics/publishedVersio

    Establishment of canine hemangiosarcoma xenograft models expressing endothelial growth factors, their receptors, and angiogenesis-associated homeobox genes

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Human hemangiosarcoma (HSA) tends to have a poor prognosis; its tumorigenesis has not been elucidated, as there is a dearth of HSA clinical specimens and no experimental model for HSA. However, the incidence of spontaneous HSA is relatively high in canines; therefore, canine HSA has been useful in the study of human HSA. Recently, the production of angiogenic growth factors and their receptors in human and canine HSA has been reported. Moreover, the growth-factor environment of HSA is very similar to that of pathophysiological angiogenesis, which some homeobox genes regulate in the transcription of angiogenic molecules. In the present study, we established 6 xenograft canine HSA tumors and detected the expression of growth factors, their receptors, and angiogenic homeobox genes.</p> <p>Methods</p> <p>Six primary canine HSAs were xenografted to nude mice subcutaneously and serially transplanted. Subsequently, the expressions of vascular endothelial growth factor (VEGF)-A, basic fibroblast growth factors (bFGF), flt-1 and flk-1 (receptors of VEGF-A), FGFR-1, and angiogenic homeobox genes HoxA9, HoxB3, HoxB7, HoxD3, Pbx1, and Meis1 were investigated in original and xenograft tumors by histopathology, immunostaining, and reverse transcription polymerase chain reaction (RT-PCR), using canine-specific primer sets.</p> <p>Results</p> <p>Histopathologically, xenograft tumors comprised a proliferation of neoplastic cells that were varied in shape, from spindle-shaped and polygonal to ovoid; some vascular-like structures and vascular clefts of channels were observed, similar to those in the original tumors. The expression of endothelial markers (CD31 and vWF) was detected in xenograft tumors by immunohistochemistry and RT-PCR. Moreover, the expression of VEGF-A, bFGF, flt-1, flk-1, FGFR-1, HoxA9, HoxB3, HoxB7, HoxD3, Pbx1, and Meis1 was detected in xenograft tumors. Interestingly, expressions of bFGF tended to be higher in 3 of the xenograft HSA tumors than in the other tumors.</p> <p>Conclusion</p> <p>We established 6 xenograft canine HSA tumors in nude mice and found that the expressions of angiogenic growth factors and their receptors in xenograft HSAs were similar to those in spontaneous HSA. Furthermore, we detected the expression of angiogenic homeobox genes; therefore, xenograft models may be useful in analyzing malignant growth in HSA.</p

    Cold atoms in space: community workshop summary and proposed road-map

    Get PDF
    We summarise the discussions at a virtual Community Workshop on Cold Atoms in Space concerning the status of cold atom technologies, the prospective scientific and societal opportunities offered by their deployment in space, and the developments needed before cold atoms could be operated in space. The cold atom technologies discussed include atomic clocks, quantum gravimeters and accelerometers, and atom interferometers. Prospective applications include metrology, geodesy and measurement of terrestrial mass change due to, e.g., climate change, and fundamental science experiments such as tests of the equivalence principle, searches for dark matter, measurements of gravitational waves and tests of quantum mechanics. We review the current status of cold atom technologies and outline the requirements for their space qualification, including the development paths and the corresponding technical milestones, and identifying possible pathfinder missions to pave the way for missions to exploit the full potential of cold atoms in space. Finally, we present a first draft of a possible road-map for achieving these goals, that we propose for discussion by the interested cold atom, Earth Observation, fundamental physics and other prospective scientific user communities, together with the European Space Agency (ESA) and national space and research funding agencies.publishedVersio
    corecore