Nanomaterials Design and Fabrication for Solar Energy Conversion and Photocatalysis Applications

The use of nanomaterials in solar energy conversion and photocatalytic degradation of environmental pollutants represents an opportunity to improve the performance, density, and ease of transportation in renewable resources. Among renewables resources, solar energy is considered as the largest exploitable resource, supplying the earth with energy in 1 hour equivalent to mankind’s total energy consumption in an entire year. Collecting and storing sunlight in chemical bonds (solar fuel) using photoelectrochemical water splitting (PEC) is a promising, a clean and sustainable way for hydrogen generation. Moreover, the photocatalytic process has great potential and high efficiency for removal of organic pollutants from water under direct natural sunlight irradiation. The aim of this project is to design, fabricate, characterize and performance enhancement of novel semiconductor materials that could efficiently harvest and store solar energy by splitting water to produce hydrogen and to perform dye degradation as well. The lack of suitable p-type photocathode has been considered and the focus of this work was to design and develop the new stable visible light absorbing photocathode materials. In pursuit of the stable photocathode, in this work YFeO3, which is a cheap and abundant material, with promising properties, and so was chosen as the photocathode in the development of the PEC cell. YFeO3 thin films were produced by spray pyrolysis technique onto fluorine-doped tin oxide film on glass. Results showed that YFeO3 photoelectrode has achieved a photocurrent of 0.6 mA cm-2 at 0.5 V vs. RHE and maximum of 0.41 μmol/cm2 of hydrogen has obtained as well. Similarly, to look for suitable and cheap materials for environmental remediation, Bi2WO6 thin films were produced by spray pyrolysis and aerosol-assisted chemical vapour deposition techniques. Results showed that the nanostructure and texture of the films can be controlled by controlling the deposition parameters. Moreover, photocatalytic degradation of rhodamine B (RhB) and methylene blue (MB) dyes have been successfully achieved. Finally, α-Fe2O3 films were fabricated as counter electrodes for dye-sensitized solar cells in order to compete for platinum counter electrode. These films were fabricated using aerosol-assisted chemical vapour deposition and spray pyrolysis techniques. The results showed that the performance of the samples prepared by aerosol-assisted chemical vapour deposition as a counter electrodes is higher than of the samples prepared by spray pyrolysis

Combined effects of different temperature-time modes on the mechanical characteristics of sous-vide and conventional oven-cooked camel meat

Camel meat was subjected to sous-vide and conventional oven cooking at different combinations of temperature (70, 80, 90, and 100 °C) and time (30, 60, 90, 120, 150, and 180 minutes). The influence on the mechanical properties (shear force, penetration force, and texture profile) were studied. In general, our results revealed significant differences (p ≤ 0.05) between the sous-vide and conventional oven cooking methods for most of the studied parameters. Increasing the sous-vide cooking temperature-time combination resulted in lower shear and penetration forces. Moreover, a clear decline in meat hardness, chewiness, and gumminess was observed. Sous-vide cooking depends on water for cooking, where the thermal conductivity coefficient is high and uniform. The textural changes during sous-vide cooking made the meat more homogenous and tender. Conversely, the conventional oven method depends on dry air heat where the thermal conductivity coefficient is low in comparison with sous-vide cooking. The elevation of the penetration force, hardness, chewiness, and gumminess along with the increasing temperature-time values combination was obvious for the conventional oven-cooked meat

Patient safety attitudes and their predictors among emergency healthcare providers in a military medical city in the Kingdom of Saudi Arabia: a cross-sectional study

BackgroundThe increase in the number of patient safety incidents poses a challenge for hospital management. Various studies have been conducted on the safety of patients in healthcare settings, but gaps exist concerning the attitude of healthcare providers (HCPs) toward the safety of patients, including those in the emergency department (ED) in Saudi Arabian hospitals.AimThis study aimed to determine the attitude of HCPs toward patient safety in the ED at Prince Sultan Military Medical City (PSMMC) and to identify demographic factors predictive of HCPs’ attitude.MethodsA descriptive–correlational design was used. The study was conducted on a convenience sample of 202 HCPs working in the ED at PSMMC. Data were collected in December of 2022 and analyzed using SPSS v.23. Multiple linear regression analyses were performed separately for the six domains and overall patient safety attitude as dependent variables. For the seven models, the demographic variables were considered predictor variables.ResultsOverall, HCPs demonstrated a positive attitude toward patient safety (Mean = 3.75/5). Among the six domains, job satisfaction scored highest (Mean = 3.96), while stress recognition scored lowest (Mean = 3.54). However, the respondents reported some patient safety issues and agreed on the difficulty in speaking up if they perceived a problem with patient care, as well as in discussing errors. Significant relationships and predictors were established in all six dimensions and in the overall patient safety attitude. The study findings revealed that three demographic variables, namely, certification in ED (p = 0.044), value of patient safety (p = 0.001), and profession (p = 0.014), demonstrated significant correlations with the overall attitude toward patient safety. Furthermore, years of experience as an HCP in ED (p = 0.019), value of patient safety (p = 0.004), and profession (p = 0.047) were identified as predictors of the overall patient safety attitude.ConclusionThe overall attitude of HCPs toward patient safety in the ED at PSMMC was found to be positive across all six domains and overall. Several demographic factors were identified as significantly influencing their positive attitudes toward patient safety. However, some patient safety issues still need to be resolved, needing interventional and strategic solutions from hospital administration. These solutions should take into account, and give high consideration to, the significant demographic factors identified as predictors of HCPs’ attitudes toward patient safety

Ketamine-based sedation use in mechanically ventilated critically ill patients with COVID-19: A multicenter cohort study

Backgrounds: Ketamine possesses analgesia, anti-inflammation, anticonvulsant, and neuroprotection properties. However, the evidence that supports its use in mechanically ventilated critically ill patients with COVID-19 is insufficient. The study's goal was to assess ketamine's effectiveness and safety in critically ill, mechanically ventilated (MV) patients with COVID-19. Methods: Adult critically ill patients with COVID-19 were included in a multicenter retrospective-prospective cohort study. Patients admitted between March 1, 2020, and July 31, 2021, to five ICUs in Saudi Arabia were included. Eligible patients who required MV within 24 hours of ICU admission were divided into two sub-cohort groups based on their use of ketamine (Control vs. Ketamine). The primary outcome was the length of stay (LOS) in the hospital. P/F ratio differences, lactic acid normalization, MV duration, and mortality were considered secondary outcomes. Propensity score (PS) matching was used (1:2 ratio) based on the selected criteria. Results: In total, 1,130 patients met the eligibility criteria. Among these, 1036 patients (91.7 %) were in the control group, whereas 94 patients (8.3 %) received ketamine. The total number of patients after PS matching, was 264 patients, including 88 patients (33.3 %) who received ketamine. The ketamine group's LOS was significantly lower (beta coefficient (95 % CI): −0.26 (−0.45, −0.07), P = 0.008). Furthermore, the PaO2/FiO2 ratio significantly improved 24 hours after the start of ketamine treatment compared to the pre-treatment period (6 hours) (124.9 (92.1, 184.5) vs. 106 (73.1, 129.3; P = 0.002). Additionally, the ketamine group had a substantially shorter mean time for lactic acid normalization (beta coefficient (95 % CI): −1.55 (−2.42, −0.69), P 0.01). However, there were no significant differences in the duration of MV or mortality. Conclusions: Ketamine-based sedation was associated with lower hospital LOS and faster lactic acid normalization but no mortality benefits in critically ill patients with COVID-19. Thus, larger prospective studies are recommended to assess the safety and effectiveness of ketamine as a sedative in critically ill adult patients

The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

Aim The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. Methods This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. Results Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. Conclusion One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease

Association between rhesus and ABO blood group types and their impact on clinical outcomes in critically ill patients with COVID-19: A multi-center investigation

Background: There is increasing evidence suggesting that ABO blood type may play a role in the immunopathogenesis of COVID-19 infection. In addition to ABO blood type, the Rhesus (Rh) factor has also been implicated in various disease processes. Therefore, our study aimed to assess the association between both ABO and Rh blood types in critically ill patients with COVID-19 and their clinical outcomes. Methods: A multicenter retrospective cohort study conducted in Saudi Arabia between March 1, 2020, and July 31, 2021, involving adult COVID-19 patients admitted to Intensive Care Units, aimed to explore potential associations between rhesus blood group types (Positive versus Negative) and clinical outcomes. The primary endpoint assessed was the hospital length of stay (LOS). Other endpoints were considered secondary. Results: After propensity score matching (3:1 ratio), 212 patients were included in the final analysis. The hospital length of stay was longer in a negative Rh blood group compared with patients in the Rh-positive group (beta coefficient 0.26 (0.02, 0.51), p = 0.03). However, neither 30-day mortality (HR 0.28; 95% CI 0.47, 1.25, p = 0.28) nor in-hospital mortality (HR 0.74; 95% CI 0.48, 1.14, p = 0.17) reached statistical significance. Additionally, among the different ABO types, the A+ blood group exhibited a higher proportion of thrombosis/infarction and in-hospital mortality (28.1% and 31.2%, respectively). Conclusion: This study highlights the potential impact of blood group type on the prognosis of critically ill patients with COVID-19. It has been observed that patients with a negative Rh blood group type tend to have a longer hospital stay, while their mortality rates and complications during ICU stay are similar to the patients with a Rh-positive group

Fracture Resistance of Primary Zirconia Crowns: An In Vitro Study

In this study, we evaluated the fracture resistance of three commercially available prefabricated primary zirconia crowns and their correlation with dimensional variance. Methods: a total of 42 zirconia crowns were selected from three companies, (1) NuSmile primary zirconia crowns, (2) Cheng Crowns zirconia, and (3) Sprig EZ crowns. The crowns were divided into two groups based on their location in the oral cavity and further divided into subgroups based on the brand. All of the samples were subjected to fracture tests using a universal testing machine. Results: the mean load observed was highest with Cheng Crowns zirconia anterior crowns (1355 ± 484) and the least load was seen with Sprig EZ anterior crowns with a mean load of 339 ± 94. The mean load observed was highest with Cheng Crowns zirconia posterior crowns (1990 ± 485) followed by NuSmile posterior crowns and the least load was seen with Sprig EZ posterior crowns with a mean load of 661 ± 184. Conclusion: the Cheng crowns showed the highest fracture resistance amongst all three groups. Overall, the zirconia crowns (anterior and posterior) tested showed optimum mechanical properties to withstand the masticatory forces.</jats:p

Fracture Resistance of Primary Zirconia Crowns: An In Vitro Study

In this study, we evaluated the fracture resistance of three commercially available prefabricated primary zirconia crowns and their correlation with dimensional variance. Methods: a total of 42 zirconia crowns were selected from three companies, (1) NuSmile primary zirconia crowns, (2) Cheng Crowns zirconia, and (3) Sprig EZ crowns. The crowns were divided into two groups based on their location in the oral cavity and further divided into subgroups based on the brand. All of the samples were subjected to fracture tests using a universal testing machine. Results: the mean load observed was highest with Cheng Crowns zirconia anterior crowns (1355 ± 484) and the least load was seen with Sprig EZ anterior crowns with a mean load of 339 ± 94. The mean load observed was highest with Cheng Crowns zirconia posterior crowns (1990 ± 485) followed by NuSmile posterior crowns and the least load was seen with Sprig EZ posterior crowns with a mean load of 661 ± 184. Conclusion: the Cheng crowns showed the highest fracture resistance amongst all three groups. Overall, the zirconia crowns (anterior and posterior) tested showed optimum mechanical properties to withstand the masticatory forces