Ultra low power wearable sleep diagnostic systems

Sleep disorders are studied using sleep study systems called Polysomnography that records several biophysical parameters during sleep. However, these are bulky and are typically located in a medical facility where patient monitoring is costly and quite inefficient. Home-based portable systems solve these problems to an extent but they record only a minimal number of channels due to limited battery life. To surmount this, wearable sleep system are desired which need to be unobtrusive and have long battery life. In this thesis, a novel sleep system architecture is presented that enables the design of an ultra low power sleep diagnostic system. This architecture is capable of extending the recording time to 120 hours in a wearable system which is an order of magnitude improvement over commercial wearable systems that record for about 12 hours. This architecture has in effect reduced the average power consumption of 5-6 mW per channel to less than 500 uW per channel. This has been achieved by eliminating sampled data architecture, reducing the wireless transmission rate and by moving the sleep scoring to the sensors. Further, ultra low power instrumentation amplifiers have been designed to operate in weak inversion region to support this architecture. A 40 dB chopper-stabilised low power instrumentation amplifiers to process EEG were designed and tested to operate from 1.0 V consuming just 3.1 uW for peak mode operation with DC servo loop. A 50 dB non-EEG amplifier continuous-time bandpass amplifier with a consumption of 400 nW was also fabricated and tested. Both the amplifiers achieved a high CMRR and impedance that are critical for wearable systems. Combining these amplifiers with the novel architecture enables the design of an ultra low power sleep recording system. This reduces the size of the battery required and hence enables a truly wearable system.Open Acces

Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals &lt;1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Elective cancer surgery in COVID-19-free surgical pathways during the SARS-CoV-2 pandemic: An international, multicenter, comparative cohort study

PURPOSE As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19–free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19–free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19–free surgical pathways. Patients who underwent surgery within COVID-19–free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19–free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score–matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19–free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION Within available resources, dedicated COVID-19–free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

Elective Cancer Surgery in COVID-19-Free Surgical Pathways During the SARS-CoV-2 Pandemic: An International, Multicenter, Comparative Cohort Study.

PURPOSE: As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19-free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS: This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19-free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS: Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19-free surgical pathways. Patients who underwent surgery within COVID-19-free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19-free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score-matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19-free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION: Within available resources, dedicated COVID-19-free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

Results of Radiofrequency Ablation of Permanent Atrial Fibrillation of >2 Years Duration and Left Atrial Size >5 cm Using 2-mm Irrigated Tip Ablation Catheter and Targeting Areas of Complex Fractionated Atrial Electrograms

Complex fractionated atrial electrograms (CFAEs) have shown promise as target sites for ablation of atrial fibrillation (AF); however, the data are limited with regard to patients with a large left atrium (LA) (>5 cm), and/or a permanent AF duration of >2 years. We tested the hypothesis that ablation of user-defined, computer-generated CFAE and pulmonary vein isolation, without additional lines would help long-term maintenance of sinus rhythm (SR). A total of 21 patients, 9 men and 12 women, aged 32 to 78 years (mean 44 ± 3.3) were selected. All had chronic AF for >2 years (range 2 to 20; mean 3.8) and a LA of 5.3 to 11.3 cm (mean 6.4 cm). The underlying structural heart disease was rheumatic mitral valve disease in 18, aortic stenosis in 1, and hypertension in 2. Mapping and ablation was done using the NAVx Ensite system and a 2-mm-tip IBI Therapy Cool Path ablation catheter. The target included circumferential pulmonary vein ablation and elimination of areas in the LA and proximal coronary sinus showing CFAEs. During ablation, 3 patients converted to SR. In 15 others, significant organization of the atrial activity occurred. They then underwent successful electrical cardioversion. Three patients showed no change in atrial activity nor had electrical cardioversion. No procedural complications occurred. Patients took oral amiodarone for 3 months after the procedure. At 3 to 12 months (mean 9.8) of follow-up, 3 patients who were in AF at the end of the ablation procedure continued to be in AF. Of the rest, all but 3 were able to maintain SR without antiarrhythmic drugs. In conclusion, ablation using a 2-mm tip irrigation catheter, targeting user-defined CFAEs and pulmonary vein isolation facilitated maintenance of SR in most patients with a LA >5 cm and an AF duration of >2 years

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Not AvailableThe present study was undertaken to test vip3A protein from Bacillus thuringiensis for use against lepidopteran pests especially Spodoptera litura and whether cloning and expression of the vip3A gene will help in formulating an improved bioinsecticide. Eight isolates that showed amplification of the vip3A gene (675bp) were selected from 150 B. thuringiensis isolates. The isolate BT-EG1 was selected for further studies as the vip3A protein extracts from this isolate was found to cause mortality of Spodoptera litura (LC 50 of 9.09-9.92 µg/ml). The 2.367bp complete CDS was amplified using VCL1 and VCL2 specific primers and cloned into P UC19 at NdeI and XhoI restriction sites. The positive clones were sequence confirmed. The vip3A was the successfully cloned into pET21a (NdeI/XhoI) expression vector and confirmed by restriction digestion and SDS-PAGE. The crude protein extracts obtained after 16h of IPTG induction showed a LC 50 of 5.83 µg/ml against S. litura at 72h. The extracts were however highly toxic to Plutella xylostella (LC 50 of 0.43 µg/ml after 16h of IPTG induction at 48h). The extracts however did not cause mortality of Helicoverpa armigera suggested the requirement of a combination of vip proteins for broad spectrum activity.Not Availabl

New Flavone-Cyanoacetamide Hybrids with a Combination of Cholinergic, Antioxidant, Modulation of β‑Amyloid Aggregation, and Neuroprotection Properties as Innovative Multifunctional Therapeutic Candidates for Alzheimer’s Disease and Unraveling Their Mechanism of Action with Acetylcholinesterase

In line with the modern multi-target-directed ligand paradigm of Alzheimer’s disease (AD), a series of 19 compounds composed of flavone and cyanoacetamide groups have been synthesized and evaluated as multifunctional agents against AD. Biological evaluation demonstrated that compounds <b>7j</b>, <b>7n</b>, <b>7o</b>, <b>7r</b>, and <b>7s</b> exhibited excellent inhibitory potency (AChE, IC₅₀ of 0.271 ± 0.012 to 1.006 ± 0.075 μM) and good selectivity toward acetylcholinesterase, significant antioxidant activity, good modulation effects on self-induced Aβ aggregation, low cytotoxicity, and neuroprotection in human neuroblastoma SK-N-SH cells. Further, an inclusive study on the interaction of <b>7j</b>, <b>7n</b>, <b>7o</b>, <b>7r</b>, and <b>7s</b> with AChE at physiological pH 7.2 using fluorescence, circular dichroism, and molecular docking methods suggested that these derivatives bind strongly to the peripheral anionic site of AChE mostly through hydrophobic interactions. Overall, the multifunctional profiles and strong AChE binding affinity highlight these compounds as promising prototypes for further pursuit of innovative multifunctional drugs for AD