563,310 research outputs found
Visita Prof. PD Lyden a Roma
No full textPD Lyden è professore di neurologia alla UCSD dove dirige lo Stroke Center. E' un esperto di fama internazionale di terapia dell'ictus acuto. Durante il soggiorno a Roma ha partecipato alla pianificazione di attività comuni di ricerca, ha collaborato alla preparazione di un articolo scientifico e ha tenuto numerosi seminari sulle malattie cerebrovascolarigiugno 200
Novel nonalloyed thermally stable Pd/Sn and Pd/Sn/Au ohmic contacts for the fabrication of GaAs MESFETs
Full text linkGaAs metal-semiconductor field-effect transistors (MESFETs) have been fabricated utilizing thermally stable Pd/Sn and Pd/Sn/Au ohmic contacts for the first time. MESFETs with Pd/Ge ohmic contacts are fabricated for comparison. The thermal stability of the Pd/Sn, Pd/Ge and Pd/Sn/Au ohmic contacts is also presente
The CTLA-4 and PD-1/PD-L1 inhibitory pathways independently regulate host resistance to Plasmodium-induced acute immune pathology.
Full text linkThe balance between pro-inflammatory and regulatory immune responses in determining optimal T cell activation is vital for the successful resolution of microbial infections. This balance is maintained in part by the negative regulators of T cell activation, CTLA-4 and PD-1/PD-L, which dampen effector responses during chronic infections. However, their role in acute infections, such as malaria, remains less clear. In this study, we determined the contribution of CTLA-4 and PD-1/PD-L to the regulation of T cell responses during Plasmodium berghei ANKA (PbA)-induced experimental cerebral malaria (ECM) in susceptible (C57BL/6) and resistant (BALB/c) mice. We found that the expression of CTLA-4 and PD-1 on T cells correlates with the extent of pro-inflammatory responses induced during PbA infection, being higher in C57BL/6 than in BALB/c mice. Thus, ECM develops despite high levels of expression of these inhibitory receptors. However, antibody-mediated blockade of either the CTLA-4 or PD-1/PD-L1, but not the PD-1/PD-L2, pathways during PbA-infection in ECM-resistant BALB/c mice resulted in higher levels of T cell activation, enhanced IFN-γ production, increased intravascular arrest of both parasitised erythrocytes and CD8(+) T cells to the brain, and augmented incidence of ECM. Thus, in ECM-resistant BALB/c mice, CTLA-4 and PD-1/PD-L1 represent essential, independent and non-redundant pathways for maintaining T cell homeostasis during a virulent malaria infection. Moreover, neutralisation of IFN-γ or depletion of CD8(+) T cells during PbA infection was shown to reverse the pathologic effects of regulatory pathway blockade, highlighting that the aetiology of ECM in the BALB/c mice is similar to that in C57BL/6 mice. In summary, our results underscore the differential and complex regulation that governs immune responses to malaria parasites
MoCA and MMSE subitems’ sensitivity across the PD-cognitive spectrum
No full textreservedA sample of PD patients was administered MMSE (Mini-Mental State Examination) and MoCA (Montreal Cognitive Assessment). The aim of the study is to determine which MoCA and MMSE subitems are more sensitive in detecting cognitive abnormalities in patients with PD across the entire cognitive spectrum, ranging from PD with normal cognition (PD-NC), mild cognitive impairment (PD-MCI) and dementia (PDD). The findings could shed new light on the development of a PD-specific brief cognitive scale with good psychometric properties.A sample of PD patients was administered MMSE (Mini-Mental State Examination) and MoCA (Montreal Cognitive Assessment). The aim of the study is to determine which MoCA and MMSE subitems are more sensitive in detecting cognitive abnormalities in patients with PD across the entire cognitive spectrum, ranging from PD with normal cognition (PD-NC), mild cognitive impairment (PD-MCI) and dementia (PDD). The findings could shed new light on the development of a PD-specific brief cognitive scale with good psychometric properties
HAXPES spectra of Pd
No full textThis dataset consists of HAXPES spectra at Pd measured at SPring-8 BL46XU, and is a part of HAXPES database (MDR HAXPES DB, https://doi.org/10.48505/nims.3056) as a collection of MD
PD-1 and PD-L1 expression.
No full textWhole blood was labeled to determine PD-1 and PD-L1 subsets. (A) Histogram plots representatives of one healthy individual and one VL-HIV-1+ individual. PD-L1+ and PD-L1hi were determined in CD4+, in CD8+ and CD19+ cells. (B) Frequencies of PD-1hi or PD-L1hi in CD4+, CD8+ T and CD19+ cells and (C) MFI (median fluorescence intensity) of PD-1 and PD-L1 expression in CD4+, CD8+ T and CD19+ cells. Median [Q1-Q3]; represented. * = p<0.05 when comparing conditions. Each symbol corresponds to an individual.</p
Synthesis and analysis of adaptive Pd-integrated perovskite catalysts for effective NO<sub>x</sub>-reduction under lean conditions
No full textThe literature reports a series of precious metal integrated perovskite based catalysts revealing intelligent properties [1]. Lanthanum based perovskites are among these catalysts that are able to stabilize precious metal ions such as Pd, Pt, Rh, Ru, etc. in their crystal lattice. Precious metal ions in the catalyst respond reversibly to the changes in the exhaust gas composition by diffusing out of the perovskitic lattice as metallic nanoparticles under reducing conditions and by re-adsorbing into the crystal structure under oxidizing conditions. This behaviour improves the sintering resistance of precious metal particles and leads to enhanced NOx-reduction capability of the catalysts. Moreover, additional active species are formed in these catalysts which require less precious metal consumption in automotive catalytic converters.
The present study is devoted to the synthesis of La-based perovskite catalysts by the polymeric citrate route and their analysis to establish the adaptive behaviour of the precious metal ions. In order to investigate the state and behaviour of the palladium ions in the perovskite, the catalysts were calcined under redox conditions at different temperatures and analyzed via XRD, SEM, TEM and XPS. XRD analysis showed that the La-based perovskites form an orthorhombic phase above 700°C and palladium ions are soluble in the perovskite lattice up to this temperature. FE-SEM observations displayed that no segregation of the palladium particles or agglomerates occurs in the oxidized conditions of the perovskite based catalyst. TEM-analysis of the as-prepared perovskite confirmed the presence of palladium in the matrix (or perovskitic crystal lattice), but small oxidic palladium particles on the perovskite surface were found as well. This observation agrees well with the XPS analysis showing signals with a Pd 3d5/2 binding energy of 336.5 eV, which correspond to Pd2+ in PdO, together with signals at higher binding energies, which can be assigned to intra-crystalline Pd2+at the surface an in the bulk of the crystalline [1]. TEM-EDX mapping analysis showed that lanthanum and iron were homo-geneously distributed in the perovskite matrix, however, few cobalt- and palladium- rich zones were also found.
On reduction of a Pd-integrated perovskite catalyst in (20:1) N2:H2 atmosphere, palladium agglomerates in 10-15 nm sizes were detected indicating the diffusion of palladium ions out of the crystal structure to form Pd° as reported by Tanaka et al [1]. Binding energies of ~335.1 eV corresponding to Pd 3d5/2 were measured by XPS thus supporting the TEM and SEM observations. A Pd-supported perovskite Pd-LaFe(1-x)CoxO3 which was prepared by the classical impregnation method, clearly showed formation of palladium agglomerates in sizes up to 50 nm upon reduction treatment in 20:1 N2:H2 atmosphere. The XPS study suggested that some of the Pd-ions in the supported catalyst may have entered the first surface-layers of the perovskite lattice during the calcinations performed.
The catalytic experiments demonstrated that these catalyst offer higher effi-ciency in NOx-conversion than typical SCR-catalysts under lean conditions employing either hydrogen or propene as reducing agents. The Pd-integrated perovskite e.g. LaFe0.65Co0.3Pd0.05O3 displayed a maximum NOx-conversion of 74 % and N2-selectivity of 60 % at 206°C in the reduction of NO by H2 in the presence of 5 vol-% O2 which is better than the performance of typical platinum supported catalysts i.e. Pt/SiO2 [2] which produce mostly N2O under similar reaction conditions. These NOx-conversions values were maintained in the presence of H2O + CO2. The challenge of the H2-SCR of NOx technology is to reduce NOx at a relative wide temperature window less than 300°C. This issue can be solved by substitution of other elements at the A-site of the host perovskite structure. In fact, the addition of ceria into the A-site of the La-based perovskite resulted in improvement of the N2-selectivity (73.7 %) at the maximum NOx-conversion (72 %) in the presence of H2O and CO2 in the feed.
Furthermore a prototype was developed for catalytic testing under near real reaction conditions. For this purpose, the Pd-integrated perovskite with composition LaFe0.65Co0.3Pd0.05O3 was coated on cordierite substrates. The catalytic converter displayed a NOx-conversion of 20 % at 400°C even in the presence of 4 vol. % water vapour in the feed at high space velocity SV = 60000 h-1 during the C3H6-SCR of NOx reaction.
[1] H. Tanaka, M. Misono, Curr. Opinion in Sol. State and Mat. Sci. 5 (2001) 381-387.
[2] R. Burch, M. D. Coleman, Appl. Catal. B: Environ. 23 (1999) 115-121
Original dataset for ID 32 Pd in Thermophysical Property Database
No full textThis is the original dataset for ID 32 Pd in Thermophysical Property Database (https://thermophys.nims.go.jp/thermophysicalproperty/experiments/32). The dataset was obtained at Japan Aerospace Exploration Agency (JAXA), and is a part of Thermophysical Property Original Datasets (https://doi.org/10.48505/nims.3877) as a collection of MDR
PD-L1 expression on platelets.
No full textWhole Blood, a pure platelet pellet, and platelet poor plasma from two patients, one with positive platelet PD-L1 (A) and one with negative platelet PD-L1 (D), was processed through CellSearch® in parallel with PD-L1 staining in the 4th channel. A. Fluorescent image of positive platelet PD-L1 (PE conjugated) expression obtained from initial whole blood processed through CellSearch® using the classic method. B. Fluorescent images of PD-L1 (PE conjugated), cytokeratin (FITC-conjugated), CD-45 (APC conjugated), and DNA (DAPI) for platelet pellet from patient in panel A with positive platelet PD-L1 processed through CellSearch®. C. Fluorescent images of PD-L1 (PE conjugated), cytokeratin (FITC-conjugated), CD-45 (APC conjugated), and DNA (DAPI) for platelet poor plasma from patient in panel A with positive platelet PD-L1 processed through CellSearch®. See Methods for details. D. Florescent image of negative platelet PD-L1 (PE conjugated) expression obtained from initial whole blood processed through CellSearch® using the classic method. E. Florescent images of PD-L1 (PE conjugated), cytokeratin (FITC-conjugated), CD-45 (APC conjugated), and DNA (DAPI) for platelet pellet from patient in panel D with negative platelet PD-L1 processed through CellSearch®. F. Florescent images of PD-L1 (PE conjugated), cytokeratin (FITC-conjugated), CD-45 (APC conjugated), and DNA (DAPI) for platelet poor plasma processed from patient in panel D with negative platelet PD-L1 through CellSearch®.</p
A novel calibration method for PD measurement in power cables and joints using capacitive couplers
No full textPartial discharge (PD) measurements are universally accepted as a technique giving some indication of the state of the insulation in high voltage apparatus. Cable end users are keen to adopt an on-line PD monitoring during commissioning of systems. However, because of noisy environments and the problems of interference the conventional methods are difficult to implement. As a consequence, ultra-high frequency (UHF) / very high frequency (VHF) techniques of on-site detection of partial discharges have been developed. A technique based on the capacitive coupling has received much attention. It has been demonstrated that it is possible to using the technique to monitor the partial discharge in cables, particularly in joints/terminations. However, in order to obtain quantitative information about PD, calibration is required for this technique. Existing calibration methods are difficulty to implement on-site. In this paper a novel method is proposed and compared with the conventional method on a short piece of cable. It has been shown that individual capacitive coupler can also be accurately calibrated on-site and online using the new method, therefore it provides quantitative information about the amount of apparent discharge. In practice this is important for electricity utilities as the quantitative information about PD can be used to determine the quality of cable system and to decide whether the system needs to be repaired or replaced
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