Innovative approaches for augmenting dielectric properties in cross-linked polyethylene (XLPE): A review.

Throughout the history of power systems, power cables have been used to securely and efficiently distribute electrical energy to the destined locations. Cross-linked polyethylene (XLPE), a commonly used insulator in high-voltage cables, have several desirable properties, such as low dielectric loss, high dielectric constant, high thermal conductivity, enhanced thermal stability, and superior resistance against electrical stress. However, further improvements of XLPE's performance are needed. The incorporation of large specific surface area nanoparticles, such as boron nitride nanosheets and graphene oxide, exhibited a great potential in enhancing XLPE's properties. These nanoparticles create numerous trapping sites, even at small loading levels, due to their large interfacial regions. In addition, voltage stabilisers with polar groups can scavenge high-energy electrons generated by local electric fields, thereby inhibiting the electrical tree growth. Another important aspect of enhancing XLPE's dielectric performance is the inclusion of antioxidants with phenolic groups. These antioxidants react with peroxyl radicals, mitigating their harmful effects. This review summarises the effects of nanoparticles, voltage stabilisers, antioxidants, and polymer amalgamation on dielectric performance of XLPE as an insulation material. The major challenges in dielectric insulation such as breakdown voltage strength, electrical tree growth, structural defect, space charge accumulation, and thermal aging are addressed.

Initiation and Carbene Induced Radical Chain Reactions in CH2F2 Pyrolysis.

High temperature dissociations of organic molecules typically involve a competition between radical and molecular processes. In this work, we use a modeling, experiment, theory (MET) framework to characterize the high temperature thermal dissociation of CH2F2, a flammable hydrofluorocarbon (HFC) that finds widespread use as a refrigerant. Initiation in CH2F2 proceeds via a molecular elimination channel; CH2F2→CHF+HF. Here we show that the subsequent self-reactions of the singlet carbene, CHF, are fast multichannel processes and a facile source of radicals that initiate rapid chain propagation reactions. These have a marked influence on the decomposition kinetics of CH2F2. The inclusion of these reactions brings the simulations into better agreement with the present and literature experiments. Additionally, flame simulations indicate that inclusion of the CHF+CHF multichannel reaction leads to a noticeable enhancement in predictions of laminar flame speeds, a key parameter that is used to determine the flammability of a refrigerant.

GC Analysis of Metformin, Ranitidine and Famotidine from Pharmaceuticals and Human Serum.

A method has been designed based on gas chromatography with flame ionization detection (FID) for the separation and analyses of ranitidine, famotidine and metformin after pre-column derivatization with trifluoroacetylacetone and ethyl chloroformate. DB-1 (30 m × 0.32 mm id) column with film thickness 0.25 µm was used for the separation at an initial temperature of column was 100°C for 2 min, and ramping at 20°C/min up to 250°C, with a hold time of 3 min. The rate of nitrogen flow was 2.5 mL/min and FID was used for detection. Complete separation was obtained between all the three drugs including excess of derivatization reagents. Linear calibration curves and detection limits were obtained in the ranges 0.1-30 µg/mL and 0.011-0.015 µg/mL. The procedure was repeatable in terms of peak heights/peak areas and retention time (n = 5) for derivatization, quantitation and separation with relative standard deviations (RSDs) within 2.0-3.0%. The approach was examined for the analyses of drug products and serum after the intake of the drugs by healthy volunteers, and recoveries were obtained within 95-98% with RSDs 2.4-3.1%.

International controlled study of revascularization and outcomes following COVID-positive mechanical thrombectomy.

BACKGROUND AND PURPOSE: Previous studies suggest that mechanisms and outcomes in patients with COVID-19-associated stroke differ from those in patients with non-COVID-19-associated strokes, but there is limited comparative evidence focusing on these populations. The aim of this study, therefore, was to determine if a significant association exists between COVID-19 status with revascularization and functional outcomes following thrombectomy for large vessel occlusion (LVO), after adjustment for potential confounding factors. METHODS: A cross-sectional, international multicenter retrospective study was conducted in consecutively admitted COVID-19 patients with concomitant acute LVO, compared to a control group without COVID-19. Data collected included age, gender, comorbidities, clinical characteristics, details of the involved vessels, procedural technique, and various outcomes. A multivariable-adjusted analysis was conducted. RESULTS: In this cohort of 697 patients with acute LVO, 302 had COVID-19 while 395 patients did not. There was a significant difference (p < 0.001) in the mean age (in years) and gender of patients, with younger patients and more males in the COVID-19 group. In terms of favorable revascularization (modified Thrombolysis in Cerebral Infarction [mTICI] grade 3), COVID-19 was associated with lower odds of complete revascularization (odds ratio 0.33, 95% confidence interval [CI] 0.23-0.48; p < 0.001), which persisted on multivariable modeling with adjustment for other predictors (adjusted odds ratio 0.30, 95% CI 0.12-0.77; p = 0.012). Moreover, endovascular complications, in-hospital mortality, and length of hospital stay were significantly higher among COVID-19 patients (p < 0.001). CONCLUSION: COVID-19 was an independent predictor of incomplete revascularization and poor functional outcome in patients with stroke due to LVO. Furthermore, COVID-19 patients with LVO were more often younger and had higher morbidity/mortality rates.

Characteristics of a COVID-19 Cohort With Large Vessel Occlusion: A Multicenter International Study.

BACKGROUND: The mechanisms and outcomes in coronavirus disease (COVID-19)-associated stroke are unique from those of non-COVID-19 stroke. OBJECTIVE: To describe the efficacy and outcomes of acute revascularization of large vessel occlusion (LVO) in the setting of COVID-19 in an international cohort. METHODS: We conducted an international multicenter retrospective study of consecutively admitted patients with COVID-19 with concomitant acute LVO across 50 comprehensive stroke centers. Our control group constituted historical controls of patients presenting with LVO and receiving a mechanical thrombectomy between January 2018 and December 2020. RESULTS: The total cohort was 575 patients with acute LVO; 194 patients had COVID-19 while 381 patients did not. Patients in the COVID-19 group were younger (62.5 vs 71.2; P < .001) and lacked vascular risk factors (49, 25.3% vs 54, 14.2%; P = .001). Modified thrombolysis in cerebral infarction 3 revascularization was less common in the COVID-19 group (74, 39.2% vs 252, 67.2%; P < .001). Poor functional outcome at discharge (defined as modified Ranklin Scale 3-6) was more common in the COVID-19 group (150, 79.8% vs 132, 66.7%; P = .004). COVID-19 was independently associated with a lower likelihood of achieving modified thrombolysis in cerebral infarction 3 (odds ratio [OR]: 0.4, 95% CI: 0.2-0.7; P < .001) and unfavorable outcomes (OR: 2.5, 95% CI: 1.4-4.5; P = .002). CONCLUSION: COVID-19 was an independent predictor of incomplete revascularization and poor outcomes in patients with stroke due to LVO. Patients with COVID-19 with LVO were younger, had fewer cerebrovascular risk factors, and suffered from higher morbidity/mortality rates.

The role of antibody responses against glycans in bioprosthetic heart valve calcification and deterioration.

Bioprosthetic heart valves (BHVs) are commonly used to replace severely diseased heart valves but their susceptibility to structural valve degeneration (SVD) limits their use in young patients. We hypothesized that antibodies against immunogenic glycans present on BHVs, particularly antibodies against the xenoantigens galactose-α1,3-galactose (αGal) and N-glycolylneuraminic acid (Neu5Gc), could mediate their deterioration through calcification. We established a large longitudinal prospective international cohort of patients (n = 1668, 34 ± 43 months of follow-up (0.1-182); 4,998 blood samples) to investigate the hemodynamics and immune responses associated with BHVs up to 15 years after aortic valve replacement. Early signs of SVD appeared in <5% of BHV recipients within 2 years. The levels of both anti-αGal and anti-Neu5Gc IgGs significantly increased one month after BHV implantation. The levels of these IgGs declined thereafter but anti-αGal IgG levels declined significantly faster in control patients compared to BHV recipients. Neu5Gc, anti-Neu5Gc IgG and complement deposition were found in calcified BHVs at much higher levels than in calcified native aortic valves. Moreover, in mice, anti-Neu5Gc antibodies were unable to promote calcium deposition on subcutaneously implanted BHV tissue engineered to lack αGal and Neu5Gc antigens. These results indicate that BHVs manufactured using donor tissues deficient in αGal and Neu5Gc could be less prone to immune-mediated deterioration and have improved durability.

Delirium definition influences prediction of functional survival in patients one-year postcardiac surgery.

BACKGROUND: Delirium after cardiac surgery is associated with prolonged intensive care unit (ICU) and hospital length of stay and elevated rates of mortality. The Society of Thoracic Surgery National Database (STS-ND) includes delirium in routine data collection but restricts its definition to hyperactive symptoms. The objective is to determine whether the Confusion Assessment Method for ICU (CAM-ICU), which includes hypo- and hyperactive symptoms, is associated with improved prediction of poor 1-year functional survival following cardiac surgery. METHODS: Clinical and administrative databases were used to determine the influence of postoperative delirium on 1-year poor functional survival, defined as being institutionalized or deceased at 1 year. Patients experiencing postoperative delirium using the STS-ND definition (2007-2009) were compared with patients with delirium identified by the CAM-ICU (2010-2012). A propensity score match was undertaken, and multivariable Cox proportional hazards regression models were generated to determine risk of poor 1-year functional survival. RESULTS: There were 2756 and 2236 patients in the STS-ND and CAM-ICU cohorts, respectively. Propensity matching resulted in a cohort of 1835 patients (82.1% matched). The overall rate of delirium in the matched study population was 7.6% in the STS-ND cohort and 13.0% in the CAM-ICU cohort (P < .001). Delirium in the CAM-ICU cohort was independently associated with poor 1-year functional survival (hazard ratio, 2.58; 95% confidence interval, 1.20-5.54; P = .02); delirium in the STS-ND cohort was not associated with poor 1-year functional survival (hazard ratio, 0.92; 95% confidence interval, 0.49-1.71; P = .79). CONCLUSIONS: A systematic screening tool identifies postoperative delirium with improved prediction of poor 1-year functional survival following cardiac surgery.

Anti-neutrophil Cytoplasmic Antibody-Associated Glomerulonephritis Secondary to Hydralazine: A Case Report.

Hydralazine is a vasodilator used in the treatment of resistant hypertension. It is a safe and widely used antihypertensive medicine. Its common adverse effects include headache, rebound tachycardia, fluid retention, and angina. It is a rare cause of anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV) with pulmonary and renal involvement. We report a case of a 74-year-old woman, with over eight years of use of hydralazine, who presented to the hospital with shortness of breath and cough. Blood work revealed deranged renal function with high creatinine levels. Serology workup was positive for anti-histone antibodies (AHA), anti-nuclear antibodies (ANA), myeloperoxidase (MPO) ANCA and proteinase-3 (PR-3) ANCA. Renal biopsy showed diffusely flattened tubular epithelium, focal micro vesicular degeneration, and focal loss of the brush border of the proximal tubular epithelium. Hydralazine was stopped and the patient was treated with corticosteroids, resulting in the resolution of her kidney injury.

Perceptions Regarding COVID-19 Vaccination Among a Representative Pakistani Population Coming to Tertiary Care Cardiac Hospital.

BACKGROUND: The deleterious effects caused by coronavirus disease 2019 (COVID-19) infection have been compounded by COVID-19 vaccine hesitancy throughout the world, including Pakistan. We are lacking representative national data regarding the COVID-19 vaccine acceptance. This study aims to determine COVID-19 vaccination acceptance rates and predictors of its acceptance and hesitancy among a representative Pakistani population. METHODS: This cross-sectional study was conducted at the National Institute of Cardiovascular Disease, Karachi, from March 2021 to April 2021. Participants included patients, and their attendants visiting the outpatient clinics and healthcare workers of the institute. Participants were labeled as 'acceptant' or 'hesitant' based on their responses of 'yes' or 'no' and 'not sure' on the willingness to get vaccinated, respectively. The Chi-square test was used to calculate the significant association between different variables. A p-value ≤0.05 was set as a level of significance for all statistical analyses. RESULTS: Overall, 1500 participants were enrolled with a vaccine acceptance rate of only 49%. Factors like male gender, unmarried and employed status, higher education, high socioeconomic class, Punjabi and Sindhi ethnicity, medical professional, and self or family exposure of COVID-19 were positively related to COVID-19 vaccine acceptance. The commonest stated reason for the vaccine hesitancy was distrust in vaccine efficacy or fear of vaccine adverse effects. CONCLUSION: Vaccine hesitancy remains a serious challenge in our population, related to multiple demographic and thought factors. Focused actions and modification of these factors are the keys to conclude this COVID pandemic.

Environment-Friendly Zinc Oxide Nanorods-Grown Cellulose Nanofiber Nanocomposite and Its Electromechanical and UV Sensing Behaviors.

This paper reports a genuine environment-friendly hybrid nanocomposite made by growing zinc oxide (ZnO) nanorods on cellulose nanofiber (CNF) film. The nanocomposite preparation, characterizations, electromechanical property, and ultraviolet (UV) sensing performance are explained. CNF was extracted from the pulp by combining the 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) oxidation and the aqueous counter collision (ACC) methods. The CNF film was fabricated using doctor blade casting, and ZnO nanorods were grown on the CNF film by seeding and by a hydrothermal method. Morphologies, optical transparency, mechanical and electromechanical properties, and UV sensing properties were examined. The nanocomposite's optical transparency was more than 80%, and the piezoelectric charge constant d31 was 200 times larger than the CNF film. The UV sensing performance of the prepared ZnO-CNF nanocomposites was tested in terms of ZnO concentration, UV irradiance intensity, exposure side, and electrode materials. A large aspect ratio of ZnO nanorods and a work function gap between ZnO nanorods and the electrode material are essential for improving the UV sensing performance. However, these conditions should be compromised with transparency. The use of CNF for ZnO-cellulose hybrid nanocomposite is beneficial not only for electromechanical and UV sensing properties but also for high mechanical properties, renewability, biocompatibility, flexibility, non-toxicity, and transparency.

Quantification of pial collateral pressure in acute large vessel occlusion stroke: basic concept with patient outcomes.

PURPOSE: Pial collateral perfusion to the ischemic penumbra plays a critical role in determining patient outcomes in acute stroke. We aimed to assess the validity and reliability of an intra-procedural technique for measuring and quantifying the pial collateral pressure (QPCP) to ischemic brain tissue during acute stroke secondary to LVO. QPCP measurements were correlated with standard computed tomography angiography (CTA) and digital subtraction angiography imaging assessments of pial collateral perfusion and outcomes after mechanical endovascular revascularization (MER). METHODS: This prospective cohort study included 60 consecutive patients with middle cerebral artery (MCA)-M1 and proximal M2 occlusions. QPCP measurements were obtained during MER. The validity of QPCP measurements was evaluated using four widely accepted collateral grading scales. QPCP measurements were also analyzed as a predictor of patient outcomes utilizing National Institute of Health Stroke Scale reduction at 24 h and modified Rankin Scale (mRS) scores at 30 days. RESULTS: QPCP measurements and QPCP ratio (QPCP/systemic mean arterial blood pressure) showed a statistically significant association with single-phase pretreatment CTA Maas and American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology binary grading scales. Patient outcomes demonstrated for every 10-unit increase in QPCP, the odds of mRS 0-2 at 30 days increased by 76% (p = 0.019). CONCLUSION: QPCP measurements related best with the pretreatment CTA Maas collateral grading scale but were more strongly associated with patient outcomes than any of the four widely accepted collateral grading scales. Greater QPCP was significantly associated with better overall patient outcomes as defined by mRS at 30 days.

Cranial angiomatoid fibrous histiocytoma: A case report and review of literature.

BACKGROUND: Angiomatoid fibrous histiocytoma (AFH) is a rare low-grade soft-tissue tumor that typically arises from the deep dermal and subcutaneous tissue of the extremities in children and young adults. Intracranial AFH is exceedingly rare, and only four cases of primary AFH tumors have been reported to date. CASE DESCRIPTION: A 43-year-old male presented to our hospital with headaches, vision changes, and a known brain tumor suspected to be an atypical meningioma. After undergoing craniotomy for resection of the mass, the immunomorphologic features of the resected tumor showed typical features of AFH with ESWR1 (exon7) - ATF1 (exon 5) fusion. CONCLUSION: AFH is a difficult tumor to diagnose with imaging and histologic studies. Thus, further knowledge is necessary - particularly of intracranial cases - to aid clinicians in its diagnosis and management.

Taxation and tobacco plain packaging effect on Saudi smokers quitting intentions in Riyadh city, Saudi Arabia.

OBJECTIVES: The current research aims to study the impact of raising tobacco tax and implementation of plain packaging on male smokers' quitting intentions in Saudi Arabia. METHODS: The study adopts a quantitative approach where close-ended questionnaires are distributed among 1,015 male participants from different regions of Riyadh city, Saudi Arabia. Bivariate analysis and logistic regression analysis are conducted using SPSS software to analyze the collected primary data. RESULTS: The study found a significant association of taxation and plain packaging on the quitting intentions of smokers. On taxation, while a considerable number of participants (46.5%) stated that they would not quit smoking if the cigarette prices increased, participants who were planning to give up smoking said it would strengthen their intention (p less than 0.001). In addition, logistic regression was performed to identify the independent predictors of quitting intention. Participants who did not want to apply the concept of plain packaging to Saudi Arabia were more likely to have quitting intention (odds ratio: 2.30 [1.61-3.28]) in comparison to those who wanted to apply the concept. CONCLUSION: Although the current price of cigarette packs reported to be very high by the participants, imposing a new higher tax may motivate smokers who had plans to quit in the near future. Plain packaging seems to be an effective new strategy in addition to tobacco taxation in Saudi Arabia, yet, more time and further research are required to assess the effectiveness of the strategy.