1,532 research outputs found
Full and ideal mixing behavior between Zr-Wd (K2ZrSi3O9) and Ti-Wd (K2TiSi3O9): evidences from mineral chemistry, X-ray diffraction pattern and Raman spectrum
No full textA series of wadeite solid solutions (Wd(ss)) along the join K2ZrSi3O9 (Zr-wadeite, Zr-Wd)-K2TiSi3O9 (Ti-wadeite, Ti-Wd) was synthesized at 2 GPa and 1,200-1,400 A degrees C for 24 h with a piston-cylinder apparatus. The chemical composition data demonstrated that Ti and Zr readily substitute for each other, and a full series of Wd(ss) exists between the Zr-Wd and Ti-Wd end-members at the P-T conditions of our synthesizing experiments. The volume-composition relationship at ambient P-T conditions did not show any significant deviation from the Vegard's law, indicating a nearly ideal mixing between the Zr-Wd and Ti-Wd. All the Raman peaks observed at ambient P-T conditions were linearly correlated with the composition, suggesting an almost full structural relaxation for the Wd(ss). These findings suggest that the complete mixing behavior along the join K2ZrSi3O9-K2TiSi3O9, as demonstrated by our high-P experiments, may extend to a much wider range of P-T conditions. Consequently, the coexistence of the Zr-Wd and Ti-Wd in the lamproites from the Leucite Hills, Wyoming, may be due to a chemical composition change of the magma rather than a crystal structural limit.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000350310900006&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Materials Science, MultidisciplinaryMineralogySCI(E)[email protected]
Contrast-enhanced CMR in patients after percutaneous closure of the left atrial appendage: A pilot study
No full textAbstract Background To evaluate the feasibility and value of first-pass contrast-enhanced dynamic and post-contrast 3D CMR in patients after transcatheter occlusion of left atrial appendage (LAA) to identify incorrect placement and persistent leaks. Methods 7 patients with different occluder systems (n = 4 PLAATO; n = 2 Watchman; n = 1 ACP) underwent 2 contrast-enhanced (Gd-DOTA) CMR sequences (2D TrueFISP first-pass perfusion and 3D-TurboFLASH) to assess localization, artifact size and potential leaks of the devices. Perfusion CMR was analyzed visually and semi-quantitatively to identify potential leaks. Results All occluders were positioned within the LAA. The ACP occluder presented the most extensive artifact size. Visual assessment revealed a residual perfusion of the LAA apex in 4 cases using first-pass perfusion and 3D-TurboFLASH indicating a suboptimal LAA occlusion. By assessing signal-to-time-curves the cases with a visually detected leak showed a 9-fold higher signal-peak in the LAA apex (567 ± 120% increase from baseline signal) than those without a leak (61 ± 22%; p Conclusion This CMR pilot study provides valuable non-invasive information in patients after transcatheter occlusion of the LAA to identify correct placement and potential leaks. We recommend incorporating CMR in future clinical studies to evaluate new device types.</p
Histopathology of postpercutaneous transluminal coronary angioplasty remodeling in human coronary arteries
No full textBACKGROUND:
We studied the histomorphometric correlates of long-term successful coronary balloon angioplasty (percutaneous transluminal coronary angioplasty [PTCA]). Restenosis after PTCA may occur secondary to the failure of compensatory arterial enlargement or post-PTCA arterial constriction. The histopathology of this process in human subjects remains poorly defined.
METHODS:
Forty-two coronary segments from 41 patients treated with PTCA 60 +/- 58 weeks before death were studied. The histomorphometric findings at the PTCA site were compared with those obtained at a proximal reference site.
RESULTS:
Histologic long-term success was seen in 18 (43%) of 42 arteries. Histologically successful PTCA arteries (PTCA site lumen of >/=50% of the reference lumen) demonstrated a larger acute lumen, smaller plaque size (normalized to the internal elastic lamina area), and thinner adventitia compared with histologic failures. Relative to the reference sites, histologically successful PTCA showed expansion of the external elastic lamina. In contrast, histologic failures showed a reduced external elastic lamina area, suggesting constrictive remodeling. Neointimal area correlated with the extent of internal elastic lamina disruption, but neither variable was related to histologic PTCA success or failure.
CONCLUSIONS:
These data provide histomorphometric confirmation of the hypothesis that constrictive remodeling, not neointimal formation, determines the long-term outcome of PTCA
Phosphorus Loss in Overfertilized Soils: The Selective P Partitioning and Redistribution Between Particle Size Separates
No full textUsing 12 well-characterised European soils contrasting in their physical and chemical properties, we demonstrate significant differences in the partitioning of phosphorus (P) between various particle size separates. Samples of each soil were subjected to one of three methods of increasingly aggressive dispersion in the order water (WD), mechanical (MD) or chemical (CD). A general, although not exclusive, inverse relationship existed between the concentration of various attributes (these included organic carbon, oxalate and dithionite iron contents, total P, resin and water extractable P) and particle size. The quantity, composition and physico-chemical properties of individual size separates were sensitive to the dispersion method used. This suggested an interaction between the ease of dispersion and particulate properties even within a single size class. Typically the total P concentration was highest in the most easily dispersed (WD) clay fraction. The total P content of the whole soil could be reasonably obtained by summing the appropriate quantities of each particle size material, however, resin and water extractable P were not adequately predicted using this approach. Together these observations have implications for laboratory and field situations where artificial disaggregation and/or selective separation and transport of fine soil material may occur. Finally a comparison of water soluble P between whole soils and their MD dispersed size fractions suggested three broad situations might exist, where either sorption processes, a precipitate or some combined P precipitate and sorption mechanism controlled P release
David Cheverill photograph, Cheltenham Fair, 1958.
No full textR. Edwards' ex-WD Scammell - registration FMW915 Queen Elizabeth II - photographed 1958
Accretion onto WD 2226-210, the central star of the Helix Nebula
No full textThe central star of the Helix Nebula, WD 2226210 presents enigmatic hard X-ray emission and mid-IR excess. The latter has been attributed to a dusty disc or a cloud-like structure around WD 2226210 formed from material of Kuiper Belt-like or comet-like objects in highly eccentric orbits. We present here a detailed analysis of multi-epoch Chandra and XMM-Newton X-ray observations of WD 2226210, comparing these to previous Einstein and ROSAT data. The luminosity of the hard X-ray component of WD 2226210 has remained basically constant in the decade from 1992 to 2002, with very subtle evidence for variability in time-scales of hours. Under the assumption that the X-ray emission from WD 2226210 is due to accretion of material, an accretion rate of M yr is estimated. The origin of the material accreted by WD 2226210 is uncertain, and can be attributed to the disc-like structure around it or to a substellar donor companion. The accretion rate proposed for the continuous replenishment by bombardment of the mid-IR-emitting structure around WD 2226210 cannot match that required by the X-ray emission. © 2024 The Author(s).The authors thank comments and suggestions from an anonymous
referee that helped improving the presentation and discussion of our
results.
SE-D thanks support to CONACyT-Mexico for a student grant.
JAT acknowledges support from UNAM PAPIIT project IN102324.
MAG acknowledges financial support from grants CEX2021-
001131-S funded by MCIN/AEI/10.13039/501100011033 and
PID2022-142925NB-I00 from the Spanish Ministerio de Ciencia,
Innovacion´ y Universidades (MCIU) cofunded with FEDER funds.
RFM acknowledges support from the Programa de Becas posdoctorales of the Direccion´ General de Asuntos del Personal Academico ´ of
the Universidad Nacional Autonoma ´ de Mexico ´ (DGAPA, UNAM,
Mexico). Y-HC acknowledges the support of the grant NSTC112-
2112-M-001-065 from the National Science and Technology Council
of Taiwan. This work is based on observations obtained with XMM–
Newton, an European Science Agency (ESA) science mission with
instruments and contributions directly funded by ESA Member States
and NASA. This research has made use of data obtained from the
Chandra Data Archive and software provided by the Chandra X-ray
Center (CXC) in the application packages CIAO. This work has made
extensive use of NASA’s Astrophysics Data System.With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2021-001131-S).Peer reviewe
Analisis Kualitas Pelayanan Pada Pasien Badan Penyelenggara Jaminan Sosial Kesehatan Kelas III Rawat Inap Rumah Sakit Umum Daerah Adnan WD Kota Payakumbuh Provinsi Sumatera Barat
No full textAdnan WD Payakumbuh Regional General Hospital is one of the government hospitals whose duties and functions include individual health service efforts and referrals. Regional General Hospital Adnan WD Payakumbuh in accordance with the Decree of the Minister of Health of the Republic of Indonesia Number 191/Menkes/SK/II/1993 in 1978 – 1992 the status of RSUD dr. Adnaan WD is Type D and in 1993 it became Type C which is in the Payakumbuh regional government area of West Sumatra Province. Like other government hospitals, Adnan WD General Hospital Payakumbuh is also expected to be able to provide health services to patients as a whole, including efforts to improve health. So the formulation of the problem in this study is how the quality of service for patients participating in the Class III Health Social Security Administering Body (BPJS) at RSUD dr. Adnan WD Payakumbuh City, West Sumatra Province. This research method uses a descriptive qualitative research approach with data collection techniques, namely interview, observation, and documentation techniques. From the results of interviews that the authors did, the satisfaction level of patients who were hospitalized in this hospital was generally maximum. This can be seen from the five indicators that the author has determined, that the service at this hospital has changed a lot since when one of the research families was admitted to this hospital in 2018
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