62 research outputs found
Formation mechanism of electrical discharge TiC-Fe composite coatings
Comparison of electric discharge (ED) processed single deposit and continuum TiC-Fe cermet coatings, formed from a sacrificial powder metallurgy TiC tool electrode at negative polarity, on 304 stainless steel, provided insight into the ED coating (EDC) formation mechanism. A deposit from a single spark event was dominated by TiC, phase separated from a ∼2 wt% Fe matrix, with strongly aligned grains and banded microstructure, indicative of solidification from the coating/substrate interface. Conversely, a continuum coating, subjected to ∼200 spark events per location, exhibited a more complex, banded microstructure, with a mixture of equiaxed and columnar TiC grains within a ∼30 wt% Fe-based matrix, along with some concentrations of carbon from the oil dielectric. It is considered that each sparking event remelts previously solidified coating material, with or without further TiC particle incorporation, leading to gradual TiC dilution and the development of a TiC-Fe composite coating with increasing levels of substrate material forming the matrix
Short and long term outcome of bilateral pallidal stimulation in chorea-acanthocytosis
BACKGROUND:
Chorea-acanthocytosis (ChAc) is a neuroacanthocytosis syndrome presenting with severe movement disorders poorly responsive to drug therapy. Case reports suggest that bilateral deep brain stimulation (DBS) of the ventro-postero-lateral internal globus pallidus (GPi) may benefit these patients. To explore this issue, the present multicentre (n=12) retrospective study collected the short and long term outcome of 15 patients who underwent DBS.
METHODS:
Data were collected in a standardized way 2-6 months preoperatively, 1-5 months (early) and 6 months or more (late) after surgery at the last follow-up visit (mean follow-up: 29.5 months).
RESULTS:
Motor severity, assessed by the Unified Huntington's Disease Rating Scale-Motor Score, UHDRS-MS), was significantly reduced at both early and late post-surgery time points (mean improvement 54.3% and 44.1%, respectively). Functional capacity (UHDRS-Functional Capacity Score) was also significantly improved at both post-surgery time points (mean 75.5% and 73.3%, respectively), whereas incapacity (UHDRS-Independence Score) improvement reached significance at early post-surgery only (mean 37.3%). Long term significant improvement of motor symptom severity (≥ 20 % from baseline) was observed in 61.5 % of the patients. Chorea and dystonia improved, whereas effects on dysarthria and swallowing were variable. Parkinsonism did not improve. Linear regression analysis showed that preoperative motor severity predicted motor improvement at both post-surgery time points. The most serious adverse event was device infection and cerebral abscess, and one patient died suddenly of unclear cause, 4 years after surgery.
CONCLUSION:
This study shows that bilateral DBS of the GPi effectively reduces the severity of drug-resistant hyperkinetic movement disorders such as present in ChAc
Discovery of widespread transcription initiation at microsatellites predictable by sequence-based deep neural network
Using the Cap Analysis of Gene Expression (CAGE) technology, the FANTOM5 consortium provided one of the most comprehensive maps of transcription start sites (TSSs) in several species. Strikingly, ~72% of them could not be assigned to a specific gene and initiate at unconventional regions, outside promoters or enhancers. Here, we probe these unassigned TSSs and show that, in all species studied, a significant fraction of CAGE peaks initiate at microsatellites, also called short tandem repeats (STRs). To confirm this transcription, we develop Cap Trap RNA-seq, a technology which combines cap trapping and long read MinION sequencing. We train sequence-based deep learning models able to predict CAGE signal at STRs with high accuracy. These models unveil the importance of STR surrounding sequences not only to distinguish STR classes, but also to predict the level of transcription initiation. Importantly, genetic variants linked to human diseases are preferentially found at STRs with high transcription initiation level, supporting the biological and clinical relevance of transcription initiation at STRs. Together, our results extend the repertoire of non-coding transcription associated with DNA tandem repeats and complexify STR polymorphism
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries
INTERNAL FRICTION STUDIES ON STRUCTURAL RELAXATION AND CRYSTALLIZATION IN Co75Si10B15 METALLIC GLASS
On a étudié le frottement interne /FI/ et le module de torsion en fonction de température dans l'alliage amorphe CO75Si10B15. Sur la courbe FI on a trouvé les maximums liés à la cristallisation du cobalt et à la précipitation de ces composés intermétalliques avec le bore et le silicium. Sur la courbe G/T/ on a démontré l'existance d'un processus de relaxation structurale. On a évalué l'énergie de ce processus : 0,48eV.Internal friction /IF/ and shear modulus as functions of temperature were investigated for Co75Si10B15 metallic glass. On the IF curves were found maxima associated with the crystallisation of cobalt and also with the precipitation of intermetallic compounds of cobalt with boron and silicon. A structural relaxation process was ascertained on the G/T/ curve. The energy of this process was estimated and found to be 0.48 eV
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