325 research outputs found
Enhanced Eshelby twist on thin wurtzite InP nanowires and measurement of local crystal rotation
We have performed a detailed study of the lattice distortions of InP wurtzite nanowires containing an axial screw dislocation. Eshelby predicted that this kind of system should show a crystal rotation due to the dislocation induced torque. We have measured the twisting rate and the dislocation Burgers vector on individual wires, revealing that nanowires with a 10-nm radius have a twist up to 100% larger than estimated from elasticity theory. The strain induced by the deformation has a Mexican-hat-like geometry, which may create a tube-like potential well for carriers
Galeorhinus galeus, Tope
Tope (Galeorhinus galeus) is a medium-sized (to 200 cm total length) bentho-pelagic shark, widespread in temperate waters in most oceans. It is present across the Northeast, Eastern Central, Southwest, and Southeast Atlantic, the Mediterranean Sea, the Eastern Indian, and across all of the Pacific, except in the Northwest Pacific. It occurs on continental shelves and upper to mid slopes from shallow inshore to well offshore to depths of 826 m, though most frequently to depths of 200 m. Genetic and tagging data support up to six separate subpopulations of Tope and while the species makes extensive movements within each of the subpopulations, there is no evidence of mixing between them. Tope has a particularly low biological productivity with a late age-at-maturity and triennial reproductive cycle. It is caught globally as target and bycatch in industrial and small-scale demersal and pelagic gillnet and longline fisheries, and to a lesser extent in trawl and hook-and-line fisheries. Tope is often retained for the meat and fins but is discarded or released in some areas, in line with regional management measures. Steep subpopulation and stock reductions of >80% over the past three generation lengths (79 years) have occurred in the Southwest Atlantic, southern Africa, and Australia. In the Northeast Atlantic, the subpopulation is estimated to have undergone a reduction of 76% over the past three generation lengths (79 years). The New Zealand stock is estimated to have undergone a reduction of 30?49% over the past three generation lengths (79 years). In the Northeast Pacific, a dramatic decline in the subpopulation occurred in the early 1940s, with no recovery until 1997?2004 when localized management led to a localized increase in abundance. The consistent steep subpopulation reductions across most of the analyzed subpopulations and stocks together with the lack of movement between the subpopulations are cause for serious concern. Management in Australia, probably aided by the immigration of large mature animals from New Zealand, appears to have stabilized that stock since 2000. The subpopulation in the Northeast Atlantic has been stable in recent years, possibly due to management measures, and there is some recovery in part of the Northeast Pacific. Release of this species is mandatory since 2011 off Canada. Release is mandatory in European Union waters for line-caught Tope. The global population is estimated to have undergone a reduction of 88% with the highest probability of >80% reduction over the last three generations (79 years) due to levels of exploitation, and Tope is assessed as Critically Endangered A2bd.Fil: Walker, T. I.. University of Melbourne; AustraliaFil: Rigby, C. L.. James Cook University; AustraliaFil: Pacoureau, N.. University Fraser Simon; CanadáFil: Ellis, J.. No especifĂca;Fil: Kulka, D. W.. No especifĂca;Fil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Herman, K.. Georgia Aquarium; Estados Unido
New Histamine-Related Five-Membered N-Heterocycle Derivatives as Carbonic Anhydrase I Activators
A series of histamine (HST)-related compounds were synthesized and tested for their activating properties on five physiologically relevant human Carbonic Anhydrase (hCA) isoforms (I, II, Va, VII and XIII). The imidazole ring of HST was replaced with different 5-membered heterocycles and the length of the aliphatic chain was varied. For the most interesting compounds some modifications on the terminal amino group were also performed. The most sensitive isoform to activation was hCA I (K(A) values in the low micromolar range), but surprisingly none of the new compounds displayed activity on hCA II. Some derivatives (1, 3a and 22) displayed an interesting selectivity for activating hCA I over hCA II, Va, VII and XIII
Effect of virtual reality rehabilitation on functional outcomes for return-to-work patients with Parkinson's disease: an umbrella review of systematic reviews
BACKGROUND: Parkinson's disease (PD) is a neurodegenerative disease characterized by loss of substantia nigra neurons with deficiency of dopamine. The main symptoms are tremor, rigidity and bradykinesia. Rehabilitation has an important role in the treatment of this condition and virtual reality (VR) is one of the most recent tools. OBJECTIVE: The purpose of this umbrella review is to evaluate the effectiveness of VR systems on gait control for return to work in patients with PD. METHODS: The electronic search, for reviews and meta-analysis studies that investigated the effectiveness of VR on gait control in PD patients, was performed through December 2021 using the following databases: PubMed, Scopus, PEDro, and Google Scholar. Mesh terms used were: Job integration/reintegration OR return-to-work AND Parkinson's disease AND virtual reality OR exergame. No limit on the year of publication of the article was used. CONCLUSIONS: A total of 14 articles were included in our analysis. The included evidence shows a stride length improvement in patients treated with VR compared to conventional active treatments. No difference was found in walking speed. Also, the included articles show an improvement on various measures of balance, motor function and severity of PD motor symptoms. In addition, the literature shows an improvement in the quality of life and neuropsychiatric symptoms in patients undergoing VR rehabilitation training. RESULTS: he results of our study suggest that VR rehabilitation improves gait performance, particularly stride length, thus being able to provide an improvement in the quality of life and a more effective return to work training in patients with PD
Optical phonon modes of wurtzite InP
Optical vibration modes of InP nanowires in the wurtzite phase were investigated by Raman scattering spectroscopy. The wires were grown along the [0001] axis by the vapor-liquid-solid method. The A1(TO), E2h, and E1(TO) phonon modes of the wurtzite symmetry were identified by using light linearly polarized along different directions in backscattering configuration. Additionally, forbidden longitudinal optical modes have also been observed. Furthermore, by applying an extended 11-parameter rigid-ion model, the complete dispersion relations of InP in the wurtzite phase have been calculated, showing a good agreement with the Raman experimental data
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The novel RASSF6 and RASSF10 candidate tumour suppressor genes are frequently epigenetically inactivated in childhood leukaemias.
BACKGROUND: The Ras-association family (RASSF) of tumour suppressor genes (TSGs) contains 10 members that encode proteins containing Ras-association (RA) domains. Several members of the RASSF family are frequently epigenetically inactivated in cancer, however, their role in leukaemia has remained largely uninvestigated. Also, RASSF10 is a predicted gene yet to be experimentally verified. Here we cloned, characterised and demonstrated expression of RASSF10 in normal human bone marrow. We also determined the methylation status of CpG islands associated with RASSF1-10 in a series of childhood acute lymphocytic leukaemias (ALL) and normal blood and bone marrow samples. RESULTS: COBRA and bisulphite sequencing revealed RASSF6 and RASSF10 were the only RASSF members with a high frequency of leukaemia-specific methylation. RASSF6 was methylated in 94% (48/51) B-ALL and 41% (12/29) T-ALL, whilst RASSF10 was methylated in 16% (8/51) B-ALL and 88% (23/26) T-ALL. RASSF6 and RASSF10 expression inversely correlated with methylation which was restored by treatment with 5-aza-2'deoxycytidine (5azaDC). CONCLUSION: This study shows the hypermethylation profile of RASSF genes in leukaemias is distinct from that of solid tumours and represents the first report of inactivation of RASSF6 or RASSF10 in cancer. These data show epigenetic inactivation of the candidate TSGs RASSF6 and RASSF10 is an extremely frequent event in the pathogenesis of childhood leukaemia. This study also warrants further investigation of the newly identified RASSF member RASSF10 and its potential role in leukaemia.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
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Potential for Induced Seismicity Related to the Northern California CO2 Reduction Project Pilot Test, Solano County, California
The objective of this technical report is to analyze the potential for induced seismicity due to a proposed small-scale CO{sub 2} injection project in the Montezuma Hills. We reviewed currently available public information, including 32 years of recorded seismic events, locations of mapped faults, and estimates of the stress state of the region. We also reviewed proprietary geological information acquired by Shell, including seismic reflection imaging in the area, and found that the data and interpretations used by Shell are appropriate and satisfactory for the purpose of this report. The closest known fault to the proposed injection site is the Kirby Hills Fault. It appears to be active, and microearthquakes as large as magnitude 3.7 have been associated with the fault near the site over the past 32 years. Most of these small events occurred 9-17 miles (15-28 km) below the surface, which is deep for this part of California. However, the geographic locations of the many events in the standard seismicity catalog for the area are subject to considerable uncertainty because of the lack of nearby seismic stations; so attributing the recorded earthquakes to motion along any specific fault is also uncertain. Nonetheless, the Kirby Hills Fault is the closest to the proposed injection site and is therefore our primary consideration for evaluating the potential seismic impacts, if any, from injection. Our planned installation of seismic monitoring stations near the site will greatly improve earthquake location accuracy. Shell seismic data also indicate two unnamed faults more than 3 miles east of the project site. These faults do not reach the surface as they are truncated by an unconformity at a depth of about 2,000 feet (610 m). The unconformity is identified as occurring during the Oligocene Epoch, 33.9-23.03 million years ago, which indicates that these faults are not currently active. Farther east are the Rio Vista Fault and Midland Fault at distances of about 6 miles (10 km) and 10 miles (16 km), respectively. These faults have been identified as active during the Quaternary (last 1.6 million years), but without evidence of displacement during the Holocene (the last 11,700 years). The stress state (both magnitude and direction) in the region is an important parameter in assessing earthquake potential. Although the available information regarding the stress state is limited in the area surrounding the injection well, the azimuth of the mean maximum horizontal stress is estimated at 41{sup o} and it is consistent with strike-slip faulting on the Kirby Hills Fault, unnamed fault segments to the south, and the Rio Vista Fault. However, there are large variations (uncertainty) in stress estimates, leading to low confidence in these conclusions regarding which fault segments are optimally oriented for potential slip induced by pressure changes. Uncertainty in the stress state can be substantially reduced by measurements planned when wells are drilled at the site. Injection of CO{sub 2} at about two miles depth will result in a reservoir fluid pressure increase, which is greatest at the well and decreases with distance from the well. After the injection stops, reservoir fluid pressures will decrease rapidly. Pressure changes have been predicted quantitatively by numerical simulation models of the injection. Based on these models, the pressure increase on the Kirby Hills Fault at its closest approach to the well due to the injection of 6,000 metric tons of CO{sub 2} would be a few pounds per square inch (psi), which is a tiny fraction of the natural pressure of approximately 5,000 psi at that depth. The likelihood of such a small pressure increase triggering a slip event is very small. It is even more unlikely that events would be induced at the significantly greater depths where most of the recorded earthquakes are concentrated, because it is unlikely that such a small pressure pulse would propagate downwards any appreciable distance. Therefore, in response to the specific question of the likelihood of the CO{sub 2} injection causing a magnitude 3.0 (or larger) event, this preliminary analysis suggests that no such induced or triggered events would be expected. However, it is possible that a fault, too small to be detected by the existing seismic data, yet sufficiently large to cause a magnitude 3 event, could exist in close proximity to the injection point where the pressure increase could cause slippage. However, the existence of such a fault would be detectable in the data planned for collection from the well prior to injection. We do note that natural earthquake events of up to 3.7 in magnitude have occurred in this area and would be expected to occur again regardless of the proposed CO{sub 2} injection
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