Impact of COVID-19 on Patients’ Attitudes and Perceptions of Dental Health Services: A Questionnaire Based Study in an Australian University Dental Clinic

COVID-19, the global pandemic, has significantly interrupted the provision of oral health care to many individuals. This study aims to evaluate patients’ attitudes to and perceptions of dental visits in the COVID-19 pandemic and assess if socio-economic status influences their perception of risk associated with dental visits. Patients attending the dental clinic were invited to participate in this study by completing a questionnaire administered in August 2021. Composite indicators for access, attitude, perception and socio-economic status were created based on subsets of questions. A total of 247 completed questionnaires were obtained. Analysis was performed with the perception, attitude and access indicators against the socio-economic status indicator. This study found that there is a statistically significant difference between socio-economic groups and their attitudes and perceptions around dental health care services in the current COVID-19 pandemic. Individuals from lower socio-economic status groups were less influenced by the pandemic. Participants from higher socio-economic status groups were found to be more cautious around COVID-19 and its risks

Fabrication of Tin and Zinc Gas Diffusion Electrodes for Electrochemical Reduction of Carbon Dioxide

This study explores the electrochemical reduction of carbon dioxide (CO2) using tin (Sn) and zinc (Zn) catalyst-loaded gas diffusion electrodes (GDEs). The research explores the influence of electrolytic potential and catalyst loading on the efficiency of CO2 conversion to valuable chemicals, specifically formic acid and carbon monoxide. The best Sn loading for Sn-loaded GDEs, according to the morphological study, is 7 mg.cm-2, which results in higher current density (0.33 mA.cm-2) and current efficiency (36%). An electrolytic potential of -1.3 V Vs. Ag/AgCl is identified as optimal for Sn GDEs, offering a balance between high current efficiency (35%) and controlled current density. For Zn-loaded GDEs, an optimal loading of 5 mg.cm²- yields the highest current efficiency of 19.4% and a peak current density of 0.28 mA.cm²- at an electrolytic potential of -1.55 V Vs. Ag/AgCl, in addition to highlighting the crucial role that catalyst loading and electrolytic potential play in enhancing CO2 reduction efficiency, this research offers insightful information for environmentally friendly CO2 conversion technology

Mortality of emergency abdominal surgery in high-, middle- and low-income countries

Background: Surgical mortality data are collected routinely in high-income countries, yet virtually no low- or middle-income countries have outcome surveillance in place. The aim was prospectively to collect worldwide mortality data following emergency abdominal surgery, comparing findings across countries with a low, middle or high Human Development Index (HDI). Methods: This was a prospective, multicentre, cohort study. Self-selected hospitals performing emergency surgery submitted prespecified data for consecutive patients from at least one 2-week interval during July to December 2014. Postoperative mortality was analysed by hierarchical multivariable logistic regression. Results: Data were obtained for 10 745 patients from 357 centres in 58 countries; 6538 were from high-, 2889 from middle- and 1318 from low-HDI settings. The overall mortality rate was 1⋅6 per cent at 24 h (high 1⋅1 per cent, middle 1⋅9 per cent, low 3⋅4 per cent; P < 0⋅001), increasing to 5⋅4 per cent by 30 days (high 4⋅5 per cent, middle 6⋅0 per cent, low 8⋅6 per cent; P < 0⋅001). Of the 578 patients who died, 404 (69⋅9 per cent) did so between 24 h and 30 days following surgery (high 74⋅2 per cent, middle 68⋅8 per cent, low 60⋅5 per cent). After adjustment, 30-day mortality remained higher in middle-income (odds ratio (OR) 2⋅78, 95 per cent c.i. 1⋅84 to 4⋅20) and low-income (OR 2⋅97, 1⋅84 to 4⋅81) countries. Surgical safety checklist use was less frequent in low- and middle-income countries, but when used was associated with reduced mortality at 30 days. Conclusion: Mortality is three times higher in low- compared with high-HDI countries even when adjusted for prognostic factors. Patient safety factors may have an important role. Registration number: NCT02179112 (http://www.clinicaltrials.gov)

Effects of graded barriers on the operation of split-off band infrared detectors

Increasing the operating temperature of infrared detectors is a prime importance for practical applications. The use of split-off band transitions has been proposed for high operating temperature infrared detectors. Initial results showed increasing the potential barrier for free carrier emission has led to increases in operating temperature from 150 K for a detector with an 8 \u3bcm threshold to room temperature for detector with a 4 \u3bcm threshold. However, these detectors showed a low responsivity due to the capture of carriers in each emitter. A proposal was made to use graded barriers with an offset between the barriers on the two sides of an emitter as a method of reducing the capture in the emitters. Two GaAs/AlGaAs samples with a single graded barrier (Al fraction x = 0.57 to 1 and 0.45 to 0.75, respectively) were used to test the effects. The sample with the lower barrier show responsivity increased by a factor of 3c10 or more compared to the higher graded barrier sample and detectors without the graded barrier. The higher graded barrier sample, space charge build up causes almost all potential drop across the first barrier, and hence reduces the response. Based on the modeling it is believed that this effect will be greatly reduced in detectors with multiple periods of graded barriers and emitters, allowing the full gain effects of the graded barriers to be realized.Peer reviewed: YesNRC publication: Ye

Connecting Costa Rican small scale coffee farmers to the main stream European market: an integral chain strategy for sustainable development and improved competitiveness

Abstract A method is developed for electro-deposition of thin films of the conducting polymer polythiocyanogen on conducting tin oxide glass or other conducting substrate by anodic discharge of SCN − ions form a solution KSCN in propylene carbonate. Films are found to be highly stable and resistant to heat and chemical action. SEM pictures indicate that the films are uniform and free of pin hole. Band gap and band positions are determined from optical absorption spectra and Mott-Schottky plots, respectively. A photovoltaic cell is constructed by depositing polythiocyanogen on nanocrystalline films of n-TiO 2 followed by p-CuI to form a heterojunction. Photocurrent action spectra shows that light absorption by polythiocyanogen generates the photovoltaic response. Results suggest that polythiocyanogen could find applications in optoelectronic devices

Photovoltaic infrared detection with p-type graded barrier heterostructures

Photovoltaicinfrared detectors have significant advantages over photoconductive detectors due to zero bias operation, requiring low power and having reduced low frequency noise. They also exhibit no thermally assisted tunneling currents, leading to higher operating temperatures. p-type emitter/graded barrier GaAs/AlxGa1 12xAs structures were tested as photovoltaicdetectors in the infrared region, operating under uncooled conditions and without an applied bias voltage. A photovoltaic responsivity of 450 mV/W was obtained with a detectivity (D*) of 1.2\u2009 7\u200910^6 Jones at a peak wavelength 1.8 \u3bcm at 300 K. Responsivity and D* increased to 3c1.2 V/W and 2.8\u2009 7\u200910^6 Jones, respectively, at 280 K. A non-linear improvement in responsivity was observed with increased emitter thickness.Peer reviewed: YesNRC publication: Ye

Immunohistologic Analysis of Epithelial-Cell Populations in Oral Lichen-Planus

Previous studies have demonstrated heterogeneity within lesional lymphocytes in drug‐related oral lichen planus (D‐LP) and idiopathic lichen planus (I‐LP). This study examined the phenotype of Langerhans cells (LC) and keratinocytes in non‐erosive D‐LP and I‐LP. In I‐LP, keratinocytes expressed HLA‐DR antigens whilst LC co‐expressed CDIa, MHC Class II and CD4 antigens. The high levels of expression of MHC Class II antigens by LC were maintained during short term organ culture. In I‐LP, the epithelium contained occasional CD25 + dendritic cells (putative activated LC). These cell phenotypes are suggestive of cell activation and likely result from local production of gamma interferon. In D‐LP, expression of MHC Class II antigens on LC was reduced and no CD25+ cells were detected. The epithelium contained an increased number of CD45RA+ dendritic cells. While no differences between the production of interleukin‐1 and interleukin‐1 inhibitors by tissue samples could be detected, it is likely that the variations in epithelial cell phenotypes in I‐LP and D‐LP reflect altered cytokine production