637 research outputs found

    Characteristics of polar coronal hole jets

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    High spatial- and temporal-resolution images of coronal hole regions show a dynamical environment where mass flows and jets are frequently observed. These jets are believed to be important for the coronal heating and the acceleration of the fast solar wind. We studied the dynamics of two jets seen in a polar coronal hole with a combination of imaging from EIS and XRT onboard Hinode. We observed drift motions related to the evolution and formation of these small-scale jets, which we tried to model as well. We found observational evidence that supports the idea that polar jets are very likely produced by multiple small-scale reconnections occurring at different times in different locations. These eject plasma blobs that flow up and down with a motion very similar to a simple ballistic motion. The associated drift speed of the first jet is estimated to be ≈\approx 27 km s−1^{-1}. The average outward speed of the first jet is ≈171\approx 171 km s−1^{-1}, well below the escape speed, hence if simple ballistic motion is considered, the plasma will not escape the Sun. The second jet was observed in the south polar coronal hole with three XRT filters, namely, C−_{-}poly, Al−_{-}poly, and Al−_{-}mesh filters. We observed that the second jet drifted at all altitudes along the jet with the same drift speed of ≃\simeq 7 km s−1^{-1}. The enhancement in the light curves of low-temperature EIS lines in the later phase of the jet lifetime and the shape of the jet's stack plots suggests that the jet material is falls back, and most likely cools down. To support this conclusion, the observed drifts were interpreted within a scenario where reconnection progressively shifts along a magnetic structure, leading to the sequential appearance of jets of about the same size and physical characteristics. On this basis, we also propose a simple qualitative model that mimics the observations.Comment: Accepted Astronomy and Astrophysic

    A large multilobulated ankle swelling: rare presentation of gout

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    We are presenting a case study of a male patient presented to our outpatient department with large lobulated hard swelling in subcutaneous plane of left ankle. We found large whitish soft tissue masses. We did chemical analysis of same and it showed presence of uric acid crystals. This is a very rare presentation of gout. Upto the best of our knowledge only one such lesion has been reported from Turkey. So we wish to report this rare presentation of Gout

    Subsidence Movements and Structural Damage Related to an Abandoned Coal Mine

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    An area in southwestern Illinois has been experiencing surface and subsurface movements with associated damage to surface structures. The area is underlain by an abandoned, partially extracted room-and-pillar underground coal mine. Instrumentation included TDR (Time Domain Reflectometry), Inclinometers, Sondex, Tiltplates, and precision land surveys. This paper presents the results of a 16-month cooperative study between the Department of Mining Engineering at SIUC and a local coal company

    Carrier Recombination and Generation Rates for Intravalley and Intervalley Phonon Scattering in Graphene

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    Electron-hole generation and recombination rates for intravalley and intervalley phonon scattering in Graphene are presented. The transverse and the longitudinal optical phonon modes (E2gE_{2g}-modes) near the zone center (Γ\Gamma-point) contribute to intravalley interband carrier scattering. At the zone edge (K(K′)K(K')-point), only the transverse optical phonon mode (A1′A'_{1}-mode) contributes significantly to intervalley interband scattering with recombination rates faster than those due to zone center phonons. The calculated recombination times range from less than a picosecond to more than hundreds of picoseconds and are strong functions of temperature and electron and hole densities. The theoretical calculations agree well with experimental measurements of the recombination rates of photoexcited carriers in graphene.Comment: 6 pages, 9 figure

    Extended reverse sural artery pedicle flap: a versatile and reproducible option for coverage of ankle and foot defects

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    Background: Coverage of soft tissue defects around distal third of the leg, particularly ankle and foot is a common situation faced by a plastic and reconstructive surgeon. Options available for such defects are limited due to scarcity of additional soft tissue that can be used without exposing tendons or bone. Associated conditions such as major vascular compromise, comorbidities and lack of facilities or expertise make free tissue transfer less preferred. Distally based sural artery flap has been a frequently used flap in such conditions, easy to perform and has reproducible results. We extended the reach of the flap and reproduced the results.Methods: We performed extended reverse sural artery pedicled flaps in 19 patients who presented to us between 2015 to 2017 with soft tissue defects around ankle and foot. Patients included 15 post RTA, 2 diabetic foot, 1 post resection defect and 1 post burn contracture release defect. Size of the defect ranged between 8x6cm to 14x10cm. Average follow up period was ranging from 8 months to 2.5 years.Results: All the flaps healed well without any obvious complications except one patient in whom marginal necrosis (2 cm margin of distal most flap) was observed and was secondarily treated with skin grafting.Conclusions: We observed that extended reverse sural pedicle flap is a rapid, reliable option for coverage of soft tissue defects around ankle and heel, sparing major vessel compromise and lengthy surgical procedure during free tissue transfer. This flap should be the first option for the patients with trauma and defects over weight bearing foot in whom peroneal axis vessels are preserved

    The Transcriptomic Response of Rat Hepatic Stellate Cells to Endotoxin: Implications for Hepatic Inflammation and Immune Regulation

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    With their location in the perisinusoidal space of Disse, hepatic stellate cells (HSCs) communicate with all of the liver cell types both by physical association (cell body as well as cytosolic processes penetrating into sinusoids through the endothelial fenestrations) and by producing several cytokines and chemokines. Bacterial lipopolysaccharide (LPS), circulating levels of which are elevated in liver diseases and transplantation, stimulates HSCs to produce increased amounts of cytokines and chemokines. Although recent research provides strong evidence for the role of HSCs in hepatic inflammation and immune regulation, the number of HSC-elaborated inflammatory and immune regulatory molecules may be much greater then known at the present time. Here we report time-dependent changes in the gene expression profile of inflammatory and immune-regulatory molecules in LPS-stimulated rat HSCs, and their validation by biochemical analyses. LPS strongly up-regulated LPS-response elements (TLR2 and TLR7) but did not affect TLR4 and down-regulated TLR9. LPS also up-regulated genes in the MAPK, NFκB, STAT, SOCS, IRAK and interferon signaling pathways, numerous CC and CXC chemokines and IL17F. Interestingly, LPS modulated genes related to TGFβ and HSC activation in a manner that would limit their activation and fibrogenic activity. The data indicate that LPS-stimulated HSCs become a major cell type in regulating hepatic inflammatory and immunological responses by altering expression of numerous relevant genes, and thus play a prominent role in hepatic pathophysiology including liver diseases and transplantation

    X-Ray and Ultraviolet Flares on AT Microscopii Observed by AstroSat

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    We present observations of the active M-dwarf binary AT Mic (dM4.5e+dM4.5e) obtained with the orbital observatory AstroSat. During 20 ks of observations, in the far ultraviolet (130−180130-180 nm) and soft X-ray (0.3−70.3-7 keV) spectral ranges, we detected both quiescent emission and at least five flares on different components of the binary. The X-ray flares were typically longer than and delayed (by 5−65-6 min) with respect to their ultraviolet counterparts, in agreement with the Neupert effect. Using X-ray spectral fits, we have estimated the parameters of the emitting plasma. The results indicate the presence of a hot multi-thermal corona with the average temperatures in the range of ∼7−15\sim 7-15 MK and the emission measure of ∼(2.9−4.5)×1052\sim (2.9-4.5)\times 10^{52} cm−3\textrm{cm}^{-3}; both the temperature and the emission measure increased during the flares. The estimated abundance of heavy elements in the corona of AT Mic is considerably lower than at the Sun (∼0.18−0.34\sim 0.18-0.34 of the solar photospheric value); the coronal abundance increased during the flares due to chromospheric evaporation. The detected flares had the energies of ∼1031−1032\sim 10^{31}-10^{32} erg; the energy-duration relations indicate the presence of magnetic fields stronger than in typical solar flares.Comment: Accepted for publication in Research in Astronomy and Astrophysic

    Impact of Donor Pre-Procurement Cardiac Arrest (PPCA) on Clinical Outcomes in Liver Transplantation

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    BACKGROUND Transplantation of liver grafts from deceased donors who experienced cardiac arrest prior to liver procurement is now common. This single-center study analyzed the impact of pre-donation arrest time on clinical outcomes in liver transplantation. MATERIAL AND METHODS Records of all orthotopic liver transplants performed at a single center over a 15-year period were reviewed. Donor records were reviewed and total arrest time was calculated as cumulative minutes. Post-transplant liver graft function was assessed using laboratory values. Graft survival was assessed with Cox regression analysis. RESULTS Records for 1830 deceased donor transplants were reviewed, and 521 donors experienced pre-procurement cardiac arrest (28%). Median arrest time was 21 min (mean 25 min, range 1-120 min). After transplant, the peak alanine aminotransferase and bilirubin levels for liver grafts from donors with arrest were lower compared to those for donors without arrest (p40 min arrest) demonstrated no statistically significant difference in survival at 10 years. Subgroup analysis of 93 donation after cardiac death grafts showed no significant difference for these same outcomes. CONCLUSIONS These results support the use of select deceased liver donors who experience pre-donation cardiac arrest. Pre-donation arrest may be associated with less early allograft dysfunction, but had no impact on long-term clinical outcomes. The results for donation after cardiac death donors were similar

    Designing Process for Concentration of a Low Grade Copper Ore

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    The paper deals with the results of chracterisation and flotation studies carried out on a low grade and complex copper ore sample with a view to design process for its concentration. Flotation studies were carried out under varying conditions of process parameters. Effects of gran-ulametry of the feed, dosage of sodium iso-propyl xanthate as collector, pH and gangue depressant dispersant were studied. Sulphidization technique and use of potassium octyl hydroxamate as auxiliary collector for flotation of oxidised minerals was observed to enhance copper recovery. Use of sodium silicate as depressant/dispersant for sili-ceous gangues helped in improving grade of copper conce-ntrate. Rougher followed by multi-stage cleaning were found necessary to produce a high grade copper concentrate. Based on the studies undertaken the process was designed for concentration of the low grade copper ore sample
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