54 research outputs found
Erosion Study of Tungsten Carbide films under 100 keV Kr+ ion irradiation
Tungsten carbide (WC) stands out as a crucial material for exploration in
extreme environments due to its resistance to radiation and impressive
mechanical strength. Widely utilized in cutting tools, high-wear components,
and as a potential contender for plasma-facing material in nuclear reactors,
WC's erosion behavior under surrogate irradiations is a subject of
investigation. In the present work, WC films were synthesized at two different
substrate temperatures of 400 K and 600 K using RF sputtering and were then
irradiated with 100 keV Kr1+ ions at a fluence of 1x1017 ions/cm2. The
crystalline phases of as deposited WC films were confirmed by glancing
incidence X-ray diffraction (GIXRD) measurements. Rutherford Backscattering
Spectrometry (RBS) was employed to determine the thicknesses of pristine
samples and the sputtering rate by measuring the difference in the areal
densities of the pristine and irradiated films. The erosion rate of both types
of films was found to be ~ 1.6 atoms per incident Kr+ ion. These findings
contribute to a foundational comprehension of the radiation tolerance behavior
of WC thin films, crucial for their performance in the demanding conditions of
extreme radiation.Comment: 10 pages, 5 figure
An atypical adenomatoid odontogenic tumour in the mandible: a report of a paediatric case
An adenomatoid odontogenic tumour (AOT) is a rare odontogenic tumour that is often misdiagnosed as an odontogenic cyst. To acquire additional information about AOT, all reports regarding AOT that had been cited in ‘Pub Med’ since 1990 onwards were reviewed. AOT accounts for about 1–9% of all odontogenic tumours. It is predominantly found in young and female patients, is located more often in the maxilla, and in most cases is associated with an unerupted permanent tooth. The differential diagnosis between AOT and other odontogenic tumours such as ameloblastoma should be well made to avoid extensive ablative surgery. However, AOT frequently resembles other odontogenic lesions such as dentigerous cysts or ameloblastoma. Immunohistochemically, AOT is characterized by positive reactions with certain cytokeratins. For illustration a rare case of an AOT in the mandible is presented that had atypical findings such as buccolingual cortical perforation and resorption with displacement of adjoining teeth.Keywords: adenomatoid odontogenic tumor, dentigerous cyst, odontogenic tumor, paediatric cas
Plant Species Diversity along an Altitudinal Gradient of Bhabha Valley in Western Himalaya
The present study highlights the rich species diversity of higher plants in the Bhabha Valley of western Himalaya in India. The analysis of species diversity revealed that a total of 313 species of higher plants inhabit the valley with a characteristic of moist alpine shrub vegetation. The herbaceous life forms dominate and increase with increasing altitude. The major representations are from the families Asteraceae, Rosaceae, Lamiaceae and Poaceae, suggesting thereby the alpine meadow nature of the study area. The effect of altitude on species diversity displays a hump-shaped curve which may be attributed to increase in habitat diversity at the median ranges and relatively less habitat diversity at higher altitudes. The anthropogenic pressure at lower altitudes results in low plant diversity towards the bottom of the valley with most of the species being exotic in nature. Though the plant diversity is less at higher altitudinal ranges, the uniqueness is relatively high with high species replacement rates. More than 90 % of variability in the species diversity could be explained using appropriate quantitative and statistical analysis along the altitudinal gradient. The valley harbours 18 threatened and 41 endemic species, most of which occur at higher altitudinal gradients due to habitat specificit
Mesodermal fate decisions of a stem cell: the Wnt switch
Stem cells are a powerful resource for cell-based transplantation therapies in osteodegenerative disorders, but before some kinds of stem cells can be applied clinically, several aspects of their expansion and differentiation need to be better controlled. Wnt molecules and members of the Wnt signaling cascade have been ascribed a role in both these processes in vitro as well as normal development in vivo. However some results are controversial. In this review we will present the hypothesis that both canonical and non-canonical signaling are involved in mesenchymal cell fate regulation, such as adipogenesis, chondrogenesis and osteogenesis, and that in vitro it is a timely switch between the two that specifies the identity of the differentiating cell. We will specifically focus on the in vitro differentiation of adipocytes, chondrocytes and osteoblasts contrasting embryonic and mesenchymal stem cells as well as the role of Wnts in mesenchymal fate specification during embryogenesis
Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial
Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome
Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial
Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome
Ecological Characterization of High Altitude Himalayan Landscapes in the Upper Satluj River Watershed, Kinnaur, Himachal Pradesh, India
The Indian Remote Sensing (IRS) LISS III
satellite imagery was used to classify three landscapes
in the upper Satluj river watershed in Kinnaur region
of western Himalaya viz. Nichar, Kalpa and Pooh.
These landscapes representing different eco-climatic
zones were subjected to landscape ecological analysis
and various landscape composition, patch and edge
characteristic metrics were computed to find the
extent of fragmentation in the natural vegetation.
The natural vegetation comprised of forests (10.24%),
grasslands (31.04%) and scrublands (2.95%) as the
landscape elements (LSE). These LSEs were further
segregated into different LSE types based on the
dominant species of plant communities in the landscapes.
These LSE types were surveyed for species
diversity in the three landscapes. The total landscape
area (TLA) covered by natural vegetation in Nichar,
Kalpa and Pooh landscapes was calculated to be
651.42, 529.02 and 1,673.72 km2 making the total
area covered with natural vegetation in the district as
2,854.16 km2. The Pooh block, lying in the east of the
district, though covered the largest area of the
landscape, was poor in terms of landscape composition
as compared to the Nichar block which was rich
in landscape elements as suggested by the diversity
measures. The extent of fragmentation was found to
be highest in Nichar. The Nichar landscape was
observed to be having higher mean values of species
diversity than other blocks which is consistent with
the trends observed with patches diversity. This was
in contrast to the Pooh landscape where the patch
diversity as well as the species diversity was the
lowest. Thus, an ecological analysis utilizing landscape
metrics and biodiversity field sampling of
vegetation, was attempted for such heterogenous
landscapes in high altitudes of Himalaya, which
provided a baseline data for the management and
conservation of these virgin mountainous area
Long-term ecological and biodiversity monitoring in the western Himalaya using satellite remote sensing
The IPCC in its Fourth Assessment Report (AR4)
described the Himalayan Region as data-deficient in
terms of climate monitoring. This is a serious impediment
to global research initiatives and thus necessitates
long-term ecological monitoring (LTEM) across
the Himalaya. Being governed by low temperature
conditions, the high-altitude regions in Himalaya are
more responsive to changing environmental conditions
and hence serve as better indicators. We identified few
Protected Areas (PAs) and selected forest core area
and ecotones along the temperate, sub-alpine, alpine
and cold desert ecosystems in Himachal Pradesh to
establish a network of permanent monitoring plots
(PMPs). Land and vegetation cover map of three
selected PAs has been prepared using Landsat TM
satellite data. Among the 10 PMPs, the temperate and
tree line forests in the GHNP were found to have the
highest tree diversity with Taxus wallichiana showing
good stand density and regeneration. The soil pH was
found to be higher for cold desert and lower for tree
line forests and alpine meadows. Soil total carbon and
nitrogen contents ranged from 1.08% to 13.37% and
0.094% to 1.14% respectively. It was observed that
the herbs diversity showed a positive trend with
increasing soil carbon and nitrogen concentrations.
Satellite remote sensing proves to be a useful tool in
an LTEM study, including biodiversity assessment
and climate change research in complex terrains such
as the Himalaya
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