53 research outputs found
Isozyme diversity of Garcinia gummigutta (L.) N. Robson in Western Ghat region, South India
Isozyme genetic markers are efficient tools to study genetic variations within and betweenpopulations of less known wild species as well as for studies on spatial distribution of geneticvariation. A study was conducted with four important isozyme markers namely, peroxidase,polyphenol oxidase, esterase and superoxide dismutase in Garcinia gummigutta populationcollected from Western Ghats in South India. The cluster analysis of the marker bands showedthat most of the population from similar geographic locations was the first one to groupthemselves, though a significant pattern was not noticed. The mean percentage of polymorphicloci was 52.5%. Total heterozygocity was 0.97 which is consistent with the average of tropicaltree species.
 
Simultaneous Observation of Carrier-Specific Redistribution and Coherent Lattice Dynamics in 2H-MoTe with Femtosecond Core-Level Spectroscopy
We employ few-femtosecond extreme ultraviolet (XUV) transient absorption
spectroscopy to reveal simultaneously the intra- and interband carrier
relaxation and the light-induced structural dynamics in nanoscale thin films of
layered 2H-MoTe semiconductor. By interrogating the valence electronic
structure via localized Te 4 (39-46 eV) and Mo 4 (35-38
eV) core levels, the relaxation of the photoexcited hole distribution is
directly observed in real time. We obtain hole thermalization and cooling times
of 155 fs and 38090 fs, respectively, and an electron-hole
recombination time of 1.50.1 ps. Furthermore, excitations of coherent
out-of-plane A (5.1 THz) and in-plane E (3.7 THz) lattice
vibrations are visualized through oscillations in the XUV absorption spectra.
By comparison to Bethe-Salpeter equation simulations, the spectral changes are
mapped to real-space excited-state displacements of the lattice along the
dominant A coordinate. By directly and simultaneously probing the
excited carrier distribution dynamics and accompanying femtosecond lattice
displacement in 2H-MoTe within a single experiment, our work provides a
benchmark for understanding the interplay between electronic and structural
dynamics in photoexcited nanomaterials
Growth kinetics and atomistic mechanisms of native oxidation of ZrSSe and MoS crystals
A thorough understanding of native oxides is essential for designing
semiconductor devices. Here we report a study of the rate and mechanisms of
spontaneous oxidation of bulk single crystals of ZrSSe alloys and
MoS. ZrSSe alloys oxidize rapidly, and the oxidation rate
increases with Se content. Oxidation of basal surfaces is initiated by
favorable O adsorption and proceeds by a mechanism of Zr-O bond switching,
that collapses the van der Waals gaps, and is facilitated by progressive redox
transitions of the chalcogen. The rate-limiting process is the formation and
out-diffusion of SO. In contrast, MoS basal surfaces are stable due to
unfavorable oxygen adsorption. Our results provide insight and quantitative
guidance for designing and processing semiconductor devices based on
ZrSSe and MoS, and identify the atomistic-scale mechanisms of
bonding and phase transformations in layered materials with competing anions
Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial
Background
Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
Effects of antiplatelet therapy after stroke due to intracerebral haemorrhage (RESTART): a randomised, open-label trial
Background:
Antiplatelet therapy reduces the risk of major vascular events for people with occlusive vascular disease, although it might increase the risk of intracranial haemorrhage. Patients surviving the commonest subtype of intracranial haemorrhage, intracerebral haemorrhage, are at risk of both haemorrhagic and occlusive vascular events, but whether antiplatelet therapy can be used safely is unclear. We aimed to estimate the relative and absolute effects of antiplatelet therapy on recurrent intracerebral haemorrhage and whether this risk might exceed any reduction of occlusive vascular events.
Methods:
The REstart or STop Antithrombotics Randomised Trial (RESTART) was a prospective, randomised, open-label, blinded endpoint, parallel-group trial at 122 hospitals in the UK. We recruited adults (≥18 years) who were taking antithrombotic (antiplatelet or anticoagulant) therapy for the prevention of occlusive vascular disease when they developed intracerebral haemorrhage, discontinued antithrombotic therapy, and survived for 24 h. Computerised randomisation incorporating minimisation allocated participants (1:1) to start or avoid antiplatelet therapy. We followed participants for the primary outcome (recurrent symptomatic intracerebral haemorrhage) for up to 5 years. We analysed data from all randomised participants using Cox proportional hazards regression, adjusted for minimisation covariates. This trial is registered with ISRCTN (number ISRCTN71907627).
Findings:
Between May 22, 2013, and May 31, 2018, 537 participants were recruited a median of 76 days (IQR 29–146) after intracerebral haemorrhage onset: 268 were assigned to start and 269 (one withdrew) to avoid antiplatelet therapy. Participants were followed for a median of 2·0 years (IQR [1·0– 3·0]; completeness 99·3%). 12 (4%) of 268 participants allocated to antiplatelet therapy had recurrence of intracerebral haemorrhage compared with 23 (9%) of 268 participants allocated to avoid antiplatelet therapy (adjusted hazard ratio 0·51 [95% CI 0·25–1·03]; p=0·060). 18 (7%) participants allocated to antiplatelet therapy experienced major haemorrhagic events compared with 25 (9%) participants allocated to avoid antiplatelet therapy (0·71 [0·39–1·30]; p=0·27), and 39 [15%] participants allocated to antiplatelet therapy had major occlusive vascular events compared with 38 [14%] allocated to avoid antiplatelet therapy (1·02 [0·65–1·60]; p=0·92).
Interpretation:
These results exclude all but a very modest increase in the risk of recurrent intracerebral haemorrhage with antiplatelet therapy for patients on antithrombotic therapy for the prevention of occlusive vascular disease when they developed intracerebral haemorrhage. The risk of recurrent intracerebral haemorrhage is probably too small to exceed the established benefits of antiplatelet therapy for secondary prevention
Effects of antiplatelet therapy after stroke due to intracerebral haemorrhage (RESTART): a randomised, open-label trial
Background:
Antiplatelet therapy reduces the risk of major vascular events for people with occlusive vascular disease, although it might increase the risk of intracranial haemorrhage. Patients surviving the commonest subtype of intracranial haemorrhage, intracerebral haemorrhage, are at risk of both haemorrhagic and occlusive vascular events, but whether antiplatelet therapy can be used safely is unclear. We aimed to estimate the relative and absolute effects of antiplatelet therapy on recurrent intracerebral haemorrhage and whether this risk might exceed any reduction of occlusive vascular events.
Methods:
The REstart or STop Antithrombotics Randomised Trial (RESTART) was a prospective, randomised, open-label, blinded endpoint, parallel-group trial at 122 hospitals in the UK. We recruited adults (≥18 years) who were taking antithrombotic (antiplatelet or anticoagulant) therapy for the prevention of occlusive vascular disease when they developed intracerebral haemorrhage, discontinued antithrombotic therapy, and survived for 24 h. Computerised randomisation incorporating minimisation allocated participants (1:1) to start or avoid antiplatelet therapy. We followed participants for the primary outcome (recurrent symptomatic intracerebral haemorrhage) for up to 5 years. We analysed data from all randomised participants using Cox proportional hazards regression, adjusted for minimisation covariates. This trial is registered with ISRCTN (number ISRCTN71907627).
Findings:
Between May 22, 2013, and May 31, 2018, 537 participants were recruited a median of 76 days (IQR 29–146) after intracerebral haemorrhage onset: 268 were assigned to start and 269 (one withdrew) to avoid antiplatelet therapy. Participants were followed for a median of 2·0 years (IQR [1·0– 3·0]; completeness 99·3%). 12 (4%) of 268 participants allocated to antiplatelet therapy had recurrence of intracerebral haemorrhage compared with 23 (9%) of 268 participants allocated to avoid antiplatelet therapy (adjusted hazard ratio 0·51 [95% CI 0·25–1·03]; p=0·060). 18 (7%) participants allocated to antiplatelet therapy experienced major haemorrhagic events compared with 25 (9%) participants allocated to avoid antiplatelet therapy (0·71 [0·39–1·30]; p=0·27), and 39 [15%] participants allocated to antiplatelet therapy had major occlusive vascular events compared with 38 [14%] allocated to avoid antiplatelet therapy (1·02 [0·65–1·60]; p=0·92).
Interpretation:
These results exclude all but a very modest increase in the risk of recurrent intracerebral haemorrhage with antiplatelet therapy for patients on antithrombotic therapy for the prevention of occlusive vascular disease when they developed intracerebral haemorrhage. The risk of recurrent intracerebral haemorrhage is probably too small to exceed the established benefits of antiplatelet therapy for secondary prevention
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