Waveguide-integrated silicon T centres

The performance of modular, networked quantum technologies will be strongly dependent upon the quality of their quantum light-matter interconnects. Solid-state colour centres, and in particular T centres in silicon, offer competitive technological and commercial advantages as the basis for quantum networking technologies and distributed quantum computing. These newly rediscovered silicon defects offer direct telecommunications-band photonic emission, long-lived electron and nuclear spin qubits, and proven native integration into industry-standard, CMOS-compatible, silicon-on-insulator (SOI) photonic chips at scale. Here we demonstrate further levels of integration by characterizing T centre spin ensembles in single-mode waveguides in SOI. In addition to measuring long spin T_1 times, we report on the integrated centres' optical properties. We find that the narrow homogeneous linewidth of these waveguide-integrated emitters is already sufficiently low to predict the future success of remote spin-entangling protocols with only modest cavity Purcell enhancements. We show that further improvements may still be possible by measuring nearly lifetime-limited homogeneous linewidths in isotopically pure bulk crystals. In each case the measured linewidths are more than an order of magnitude lower than previously reported and further support the view that high-performance, large-scale distributed quantum technologies based upon T centres in silicon may be attainable in the near term

Effects observed in the Latin American sector ionospheric F region during the intense geomagnetic disturbances in the early part of November 2004

The Sun was very active in the early part of November 2004. During the period of 8-10 November 2004, intense geomagnetic disturbances with two superstorms were observed. In this paper, we have investigated the generation and suppression of equatorial ionospheric irregularities and the daytime changes in the F region electron density in the Latin American sector during the period of intense geomagnetic disturbances. We present the ionospheric sounding observations carried out at Manaus and Sao Jose dos Campos, Brazil, during this geomagnetically disturbed period. Also, GPS observations obtained from several stations in Brazil, Argentina, and St. Croix, U.S. Virgin Islands, during the disturbed period are presented. During the main phase of the first superstorm, around the prereversal enhancement time (night of 7-8 November), prompt penetration of electric field was observed and the presence of equatorial ionospheric irregularities was detected from St. Croix, U.S. Virgin Islands (in the northern hemisphere) to Bahia Blanca, Argentina (in the southern hemisphere). The ionospheric sounding observations at Manaus indicate inhibition of prereversal enhancement on the nights of 9-10 and 10-11 November, possibly due to the disturbed thermospheric winds or disturbance electric fields. Virtually no phase fluctuations on the nights of 9-10 and 10-11 November were observed in the Latin American sector. During the daytime on 8 November, the vertical total electron content (VTEC) observations show a negative storm phase at Porto Alegre (Brazil) and Bahia Blanca (Argentina). Again during the daytime on 10 November, the VTEC observations show a negative storm phase from Brasilia (Brazil) to Bahia Blanca. These negative storm phases are associated with a decrease in the O/N2 ratio. During the daytime on 9 November, the VTEC observations show a positive storm phase extending from St. Croix to Porto Alegre, and again on 10 November, VTEC observations show a positive storm phase. These positive storm phases observed are possibly due to changes in large-scale wind circulation and an increase in the O/N2 ratio.Facultad de Ciencias Astronómicas y Geofísica

Effects observed in the Latin American sector ionospheric F region during the intense geomagnetic disturbances in the early part of November 2004

The Sun was very active in the early part of November 2004. During the period of 8-10 November 2004, intense geomagnetic disturbances with two superstorms were observed. In this paper, we have investigated the generation and suppression of equatorial ionospheric irregularities and the daytime changes in the F region electron density in the Latin American sector during the period of intense geomagnetic disturbances. We present the ionospheric sounding observations carried out at Manaus and Sao Jose dos Campos, Brazil, during this geomagnetically disturbed period. Also, GPS observations obtained from several stations in Brazil, Argentina, and St. Croix, U.S. Virgin Islands, during the disturbed period are presented. During the main phase of the first superstorm, around the prereversal enhancement time (night of 7-8 November), prompt penetration of electric field was observed and the presence of equatorial ionospheric irregularities was detected from St. Croix, U.S. Virgin Islands (in the northern hemisphere) to Bahia Blanca, Argentina (in the southern hemisphere). The ionospheric sounding observations at Manaus indicate inhibition of prereversal enhancement on the nights of 9-10 and 10-11 November, possibly due to the disturbed thermospheric winds or disturbance electric fields. Virtually no phase fluctuations on the nights of 9-10 and 10-11 November were observed in the Latin American sector. During the daytime on 8 November, the vertical total electron content (VTEC) observations show a negative storm phase at Porto Alegre (Brazil) and Bahia Blanca (Argentina). Again during the daytime on 10 November, the VTEC observations show a negative storm phase from Brasilia (Brazil) to Bahia Blanca. These negative storm phases are associated with a decrease in the O/N2 ratio. During the daytime on 9 November, the VTEC observations show a positive storm phase extending from St. Croix to Porto Alegre, and again on 10 November, VTEC observations show a positive storm phase. These positive storm phases observed are possibly due to changes in large-scale wind circulation and an increase in the O/N2 ratio.Facultad de Ciencias Astronómicas y Geofísica

Additional roles of a peripheral loop–loop interaction in the Neurospora VS ribozyme

Many RNAs contain tertiary interactions that contribute to folding the RNA into its functional 3D structure. In the VS ribozyme, a tertiary loop–loop kissing interaction involving stem–loops I and V is also required to rearrange the secondary structure of stem–loop I such that nucleotides at the base of stem I, which contains the cleavage–ligation site, can adopt the conformation required for activity. In the current work, we have used mutants that constitutively adopt the catalytically permissive conformation to search for additional roles of the kissing interaction in vitro. Using mutations that disrupt or restore the kissing interaction, we find that the kissing interaction contributes ∼1000-fold enhancement to the rates of cleavage and ligation. Large Mg2+-dependent effects on equilibrium were also observed: in the presence of the kissing interaction cleavage is favored >10-fold at micromolar concentrations of Mg2+; whereas ligation is favored >10-fold at millimolar concentrations of Mg2+. In the absence of the kissing interaction cleavage exceeds ligation at all concentrations of Mg2+. These data provide evidence that the kissing interaction strongly affects the observed cleavage and ligation rate constants and the cleavage–ligation equilibrium of the ribozyme

Bariatric surgery in obese patients with end-stage heart failure with ventricular assist devices

This is the raw data captured for a systematic review and individual participant data (IPD) meta-analysis evaluating the trends in body mass indices of obese patients with end-stage heart failure (ESHF) with ventricular assist devices (VADs) after undergoing bariatric surgery (BS).A systematic search was performed in ClinicalTrials.gov, Cochrane, Embase and PubMed on November 23rd, 2019. Additional searches were conducted in Google Scholar, websites of the most important journals for ESHF and BS, which also contained the proceedings of the most relevant scientific meetings in such specialties:-The Journal of Heart and Lung Transplantation-Journal of Cardiac Failure, Obesity Surgery-Surgery for Obesity and Related Diseases-Journals of following groups (journal families): --Journal of the American College of Cardiology--Circulation--European Heart JournalThese searches were performed at different before April 20th, 2020. Multiple official indexing terms and additional relevant terms for VADs and BS were used.Studies were selected if they reported IPD for the postoperative BMI of VAD patients after undergoing BS. Only patients with VAD support at the time of BS were included in the study. References selection, and data extraction were performed independently and in parallel by two investigators. In cases of disagreements, consensus was attempted through discussion, but if that was not achieved, a third investigator helped to solve the tie by simple majority. This database contains the most relevant variables from an ESHF and BS stand point.More details about data description and analyses can be found in the meta-analysis and data publication related to this project.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Laparoscopic sleeve gastrectomy in obese patients with ventricular assist devices

We identified the patients with end-stage heart failure and ventricular assist devices (VADs) who underwent bariatric surgery at Ochsner Medical Center, the only center with a VAD program in the State of Louisiana, USA. Every patient underwent a comprehensive preoperative evaluation that included psychological, metabolic, nutritional, and cardiovascular assessments. All patients were over the age of 18 years and underwent laparoscopic sleeve gastrectomy (LSG) between 2016 and January 2020. All patients were on chronic antiplatelet and anticoagulation therapy with warfarin and aspirin. Both medications were held at the time of admission and heparin infusion was started until the midnight prior to LSG. If the INR was > 1.5 the evening prior to the surgery, the patient received fresh frozen plasma and then, the INR was remeasured in the morning prior to surgery, which was performed when the INR was ≤ 1.5. Provided that the patient developed no bleeding complication, heparin was started at 200 U/hr eight hours after LSG, increased to 400 U/hr during the postoperative day one. The following day, heparin was titrated to a goal thromboplastin time of 35-45 sec with addition of aspirin. On postoperative day three, the goal thromboplastin time was increased to 45-54 sec and warfarin was restarted at a dose of 1 mg. This dataset (database: LSG in patients with VADs) includes baseline, periprocedural, and outcome data, which are described in one of the attached documents (description of variables)

Characteristics and Outcomes of Pulmonary Angioplasty With or Without Stenting for Sarcoidosis-Associated Pulmonary Hypertension: Systematic Review and Individual Participant Data Meta-Analysis

Background: Pulmonary angioplasty has been performed in patients with sarcoidosis-associated pulmonary hypertension (SAPH) but most evidence comes from case reports and small case series. Overall outcomes remain unclear. We conducted an individual participant data (IPD) meta-analysis of baseline, procedural, and outcome data of pulmonary angioplasty in patients with SAPH. Methods: We performed searches and systematically reviewed references from PubMed, Embase, Cochrane, ClinicalTrials.gov, and grey literature. We included IPD of patients who underwent pulmonary angioplasty for SAPH. Those without definitive diagnosis of sarcoidosis or with other causes of pulmonary vascular stenosis or compression were excluded. Results: Of 1293 screened references, 7 were included. IPD was obtained for 17 patients (median age 60 (55-65) years; 82.4% female); most of whom were Scadding stages III or IV and had NYHA FC III or IV. All patients with documented changes in 6-minute-walk distance (6MWD) had a significant improvement that ranged from 12.6 to 102.4% (P < 0.01). There were no deaths during a median follow-up of 6 (3-18) months. Conclusions: Pulmonary angioplasty with or without stenting of focal stenosis or compressions of pulmonary vessels may lead to significant improvement in 6MWD in patients with SAPH. However, this study had a small sample and some methodological limitations, such as analysis mostly of case reports and series. Randomized controlled clinical trials and/or large multicenter registry studies are needed to provide higher evidence in this topic

The low information content of Neurospora splicing signals: implications for RNA splicing and intron origin.

When we expressed a small (0.9 kb) nonprotein-coding transcript derived from the mitochondrial VS plasmid in the nucleus of Neurospora we found that it was efficiently spliced at one or more of eight 5' splice sites and ten 3' splice sites, which are present apparently by chance in the sequence. Further experimental and bioinformatic analyses of other mitochondrial plasmids, random sequences, and natural nuclear genes in Neurospora and other fungi indicate that fungal spliceosomes recognize a wide range of 5' splice site and branchpoint sequences and predict introns to be present at high frequency in random sequence. In contrast, analysis of intronless fungal nuclear genes indicates that branchpoint, 5' splice site and 3' splice site consensus sequences are underrepresented compared with random sequences. This underrepresentation of splicing signals is sufficient to deplete the nuclear genome of splice sites at locations that do not comprise biologically relevant introns. Thus, the splicing machinery can recognize a wide range of splicing signal sequences, but splicing still occurs with great accuracy, not because the splicing machinery distinguishes correct from incorrect introns, but because incorrect introns are substantially depleted from the genome