Dual Gate Black Phosphorous Photodetectors Using a Polymer Electrolyte for Integrated Photonics and Optoelectronics Applications

Les photodétecteurs occupent une place prépondérante dans un nombre important de dispositifs. Ceux-ci sont utilisés dans plusieurs pour les communications optiques, la détection d'images, la vision nocturne, l’inspection alimentaire, l’imagerie médicale, etc. La conception de détecteurs infrarouges requiert l’utilisation de matériaux autre que le silicium démontrant une haute efficacité, détectivité et un temps de réponse rapide. Ceux-ci sont typiquement couteux et difficiles à intégrés avec des substrats flexibles ou des circuits photoniques et optoélectroniques conventionnels. Dans cette thèse, nous présentons un photodétecteur à base de phosphore noir avec une architecture à double grille basé sur sur un électrolyte polymère solide pour des applications en photonique intégrée et en optoélectronique. La combinaison de la grille électrolytique et du photodétecteur BP conventionnel permet un contrôle efficace du transport électrique et de la modulation de la densité de porteurs dans le canal BP. Les détecteurs à double grille fabriqués avec cette approche améliorent le rapport ON / OFF de 50 fois par rapport à l’architecture conventionnelle. Ceux-ci présentent également du courant de drain avec la configuration de contact source-drain orthogonale. Finalement, l’électrolyte polymère protège les flocons de BP de l'oxydation de surface et présentent des caractéristiques électriques stables dans les conditions ambiantes. Nous obtenons une modulation du photocourant par un facteur de 4 pour des puissances incidentes variant de 0.5 mW à 5 mW. Dans cette gamme de puissance, une modulation du photocourant par un facteur de 2 est obtenu en variant la tension de grille supérieure (variée de 3V à -3V) à une longueur d'onde de 808 nm. À plus faible puissance, le photodétecteur donne une modulation de photocourant largement supérieure à l’architecture conventionnelle: environ 16 fois avec une tension de grille d'électrolyte ajustée de -2 V à 2 V par rapport au dispositif à grille inférieure qui est d'environ 2.5 fois avec une tension de grille variant de -10 V 10 V dans le proche infrarouge. Des sensibilités de centaines de mA / W sont obtenues pour les photodétecteurs BP dans les régimes visible et proche-infrarouge.----------Abstract Visible and infrared photodetectors have become important in a multitude of present-day devices that find emerging applications in several fields: optical communications, image sensing, night vision, food monitoring and medical imaging etc. However, photodetection beyond the visible region of spectrum requires investigating unconventional materials and designs that deliver superior performance in terms of photocurrent/responsivity, detectivity and response speed, that also allow ultra-low weight, low-cost, flexible and easy integration with the photonic and optoelectronic circuits. In this thesis, we report on a dual-gate black phosphorous photodetector based on solid polymer electrolyte for integrated photonics and optoelectronic applications. The combination of polymer electrolyte gate with the conventional back-gate black phosphorous (BP) photodetector allows for efficient control of electrical transport and carrier-density modulation in the BP channel. Our dual-gate field effect transistors provide a 50-fold enhancement in the drain currents that lead to high ON/OFF ratio as compared to the conventional SiO2 bottom gating. The BP FETs with polymer electrolyte film also protect BP flake from surface oxidation and show stable electrical characteristics under ambient conditions. The polymer electrolyte-based FETs also show an enhancement in the drain current with the orthogonal source-drain contact configuration. Photocurrent modulation by a factor of four by incident powers (varied from 0.5 to 5 mW) at a wavelength of 808 nm. At these modest powers, a factor of two modulation in the photocurrent is achieved by varying the top-gate voltage (from 3 V to -3 V). At lower powers, the dual-gate polymer electrolyte based BP photodetector shows a photocurrent a substantial enhancement of the photocurrent by 16 when the electrolyte gate voltage tuned from -2 V to 2 V as compared to the bottom gate device which is 2.5 times, when the gate voltage varied from -10 V to 10 V. Responsivities of the order of hundreds of mA/W are obtained for the BP photodetectors in both visible and NIR regimes

Cardiovascular Outcomes of Transradial Versus Transfemoral Percutaneous Coronary Intervention in End-Stage Renal Disease: A Regression-Based Comparison

Background: Limited data is available on the comparison of outcomes of transradial (TR) and transfemoral (TF) access for percutaneous coronary intervention (PCI) in patients with end-stage stage renal disease (ESRD). Methods: Online databases were queried to compare cardiovascular outcomes among TR. and TF in ESRD patients. The outcomes assessed included differences in mortality, cerebrovascular accidents (CVA), periprocedural myocardial infarction (MI), bleeding, transfusion, and periprocedural cardiogenic shock (CS). Unadjusted odds ratios (OR) were calculated using a random-effect effect model. Results: A total of 6 studies including 7,607 patients (TR-PCI = 1,288; TF-PCI = 6,319) were included. The overall mean age was 67.7 years, while the mean age for TR-PCI and TF-PCI was 69.7 years and 67.9 years, respectively. TR-PCI was associated with lower incidence of mortality (OR 0.46 95 % CI 0.30-0.70, p \u3c 0.05, I2 0.00 %), bleeding (OR 0.45 95 % CI 0.29, 0.68, p \u3c 0.05, I2 3.48 %), and transfusion requirement (OR 0.52 95 % CI 0.40, 0.67, p \u3c 0.05, I2 0.00 %) (Fig. 1). There were no differences among TR-PCI and TF-PCI for periprocedural MI, periprocedural CS, and CVA outcomes. Conclusion: TR access was associated with lower mortality, bleeding, and transfusion requirement as compared to TF access in patients with ESRD undergoing PCI

A clinical study of arrhythmias associated with acute coronary syndrome: a hospital based study of a high risk and previously undocumented population

Background: ACS represents a global epidemic. Arrhythmia in ACS is common. Careful investigation may lead to further improvement of prognosis. Retrospectively analyzed the year- round data of our center. Study was undertaken to analyze the incidence, frequency and type of arrhythmias in ACS. This is to aid timely intervention and to modify the outcome. Identification of the type of arrhythmia is of therapeutic and prognostic importance.Methods: This cross sectional analytical study was conducted in the Department of Cardiology, Apollo Hospitals Dhaka, from January 2019 to January 2020 with ACS patients. Enrolled consecutively and data analyzed.Results: There were 500 patients enrolled considering inclusion and exclusion criteria. Sample was subdivided into 3 groups on the type of ACS. Group-I with UA, Group-II with NSTE - ACS and Group-III with STE - ACS. Different types of arrhythmia noted. Types of arrhythmia were correlated with type of ACS. 500 patients included. Mean age 55.53±12.70, 71.6% male and 28.4% female. 60.4% hypertensive, 46.2% diabetic, 20.2% positive family history of CAD, 32.2% current smoker, 56.4% dyslipidaemic and 9.6% asthmatic. 31.2% UA, 39.2% NSTE-ACS and 29.6% STE-ACS. Type of arrhythmias noted. 22% sinus tachycardia, 20.2% sinus bradycardia, 9% atrial fibrillation, 5.2% ventricular ectopic, 4.8% supra ventricular ectopic, 2.8% bundle branch block, 2.2% atrio-ventricular block, 1% broad complex tachycardia, 0.4% narrow complex tachycardia, 0.2% sinus node dysfunction and 32.2% without any arrhythmia. Significant incidences of arrhythmia detected - respectively 29.8%, 39.2% and 31%, p<0.001.Conclusions: In conclusion, arrhythmias in ACS are common. More attention should be paid to improve their treatment and prognosis

Polyphenols-rich polyherbal mixture attenuates hepatorenal impairment, dyslipidaemia, oxidative stress and inflammation in alloxan-induced diabetic rats

ABSTRACTEffects of polyherbal mixture on hepatorenal injury and dyslipidaemia in alloxan-induced diabetic rats were evaluated. Alloxan monohydrate (120 mg/kg, i.p.) was injected into Wistar rats to induce diabetes. Animals were allotted to six groups (n = 6) and treatments were administered for consecutive six weeks as normal and diabetic controls, glibenclamide and polyherbal mixture (200, 400 and 600 mg/kg), respectively. Ameliorative effects of the polyherbal mixture were investigated by assessing FBG levels, changes in body and organ (liver and kidney) weights, biochemical parameters, oxidative stress along with inflammatory parameters in addition to histopathological examination of the liver and kidney. The results showed that alloxan-injected rats had significant (P < 0.05) hyperglycaemia in addition to elevated serum levels of hepatorenal injury indices (ALT, AST, ALP, bilirubin, total protein, albumin, creatinine, BUN and uric acid) and hyperlipidaemia evidenced by increased TC, TG, LDL-C, VLDL-C and decreased HDL-C levels. Furthermore, diabetes induction caused an increase in lipid peroxidation (MDA) and a reduction in antioxidant markers (SOD and CAT activities) as well as inflammation (TNF-α) in hepatic and renal tissues. Polyherbal mixture remarkably improved the aforementioned parameters in a dose-dependent manner. Histopathological findings supported the biochemical results. Conclusively, this study has provided novel insights into the efficacy of polyherbal mixtures in managing hyperglycaemia and its secondary complications in diabetes mellitus

Meta-Analysis Comparing Distal Radial Versus Traditional Radial Percutaneous Coronary Intervention or Angiography

Data comparing outcomes of distal radial (DR) and traditional radial (TR) access of coronary angiography and percutaneous coronary intervention (PCI) are limited. Online databases including Medline and Cochrane Central databases were explored to identify studies that compared DR and TR access for PCI. The primary outcome was the rate of radial artery occlusion (RAO) and access failure. Secondary outcomes included access site hematoma, access site bleeding, access site pain, radial artery spasm, radial artery dissection, and crossover. Unadjusted odds ratios (ORs) with a random-effect model, 95% confidence interval (CI), and p \u3c 0.05 were used for statistical significance. Metaregression was performed for 16 studies with 9,973 (DR 4,750 and TR 5,523) patients were included. Compared with TR, DR was associated with lower risk of RAO (OR 0.51, 95% CI 0.29 to 0.90, I2 = 42.6%, p = 0.02). RAO was lower in DR undergoing coronary angiography rather than PCI. Access failure rate (OR 1.77, 95% CI 0.69 to 4.55, I2 87.36%, p = 0.24), access site hematoma (OR 1.11, 95% CI 0.68 to 1.83, I2 0%, p = 0.68), access site pain (OR 2.22, 95% CI 0.28 to 17.38, I2 0%, p = 0.45), access site bleeding (OR 1.11, 95% CI 0.16 to 7.62, I2 85.11%, p = 0.91), radial artery spasm (OR 0.79, 95% CI 0.49 to 1.29, I2 0%, p = 0.35), radial artery dissection (OR 1.63, 95% CI 0.46 to 5.84, I2 0%, p = 0.45), and crossover (OR 1.54, 95% CI 0.64 to 3.70, I2 25.48%, p = 0.33) did not show any significant difference. DR was associated with lower incidence RAO when compared with TR, whereas other procedural-related complications were similar

Thigh-length compression stockings and DVT after stroke

Controversy exists as to whether neoadjuvant chemotherapy improves survival in patients with invasive bladder cancer, despite randomised controlled trials of more than 3000 patients. We undertook a systematic review and meta-analysis to assess the effect of such treatment on survival in patients with this disease

Azithromycin in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Background Azithromycin has been proposed as a treatment for COVID-19 on the basis of its immunomodulatory actions. We aimed to evaluate the safety and efficacy of azithromycin in patients admitted to hospital with COVID-19. Methods In this randomised, controlled, open-label, adaptive platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), several possible treatments were compared with usual care in patients admitted to hospital with COVID-19 in the UK. The trial is underway at 176 hospitals in the UK. Eligible and consenting patients were randomly allocated to either usual standard of care alone or usual standard of care plus azithromycin 500 mg once per day by mouth or intravenously for 10 days or until discharge (or allocation to one of the other RECOVERY treatment groups). Patients were assigned via web-based simple (unstratified) randomisation with allocation concealment and were twice as likely to be randomly assigned to usual care than to any of the active treatment groups. Participants and local study staff were not masked to the allocated treatment, but all others involved in the trial were masked to the outcome data during the trial. The primary outcome was 28-day all-cause mortality, assessed in the intention-to-treat population. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936. Findings Between April 7 and Nov 27, 2020, of 16 442 patients enrolled in the RECOVERY trial, 9433 (57%) were eligible and 7763 were included in the assessment of azithromycin. The mean age of these study participants was 65·3 years (SD 15·7) and approximately a third were women (2944 [38%] of 7763). 2582 patients were randomly allocated to receive azithromycin and 5181 patients were randomly allocated to usual care alone. Overall, 561 (22%) patients allocated to azithromycin and 1162 (22%) patients allocated to usual care died within 28 days (rate ratio 0·97, 95% CI 0·87–1·07; p=0·50). No significant difference was seen in duration of hospital stay (median 10 days [IQR 5 to >28] vs 11 days [5 to >28]) or the proportion of patients discharged from hospital alive within 28 days (rate ratio 1·04, 95% CI 0·98–1·10; p=0·19). Among those not on invasive mechanical ventilation at baseline, no significant difference was seen in the proportion meeting the composite endpoint of invasive mechanical ventilation or death (risk ratio 0·95, 95% CI 0·87–1·03; p=0·24). Interpretation In patients admitted to hospital with COVID-19, azithromycin did not improve survival or other prespecified clinical outcomes. Azithromycin use in patients admitted to hospital with COVID-19 should be restricted to patients in whom there is a clear antimicrobial indication. Funding UK Research and Innovation (Medical Research Council) and National Institute of Health Research