The pH and Concentration of Hydrogen Peroxide – Impact upon Dental Enamel Properties and Response to Dietary Staining, Erosion, and Remineralisation

Ph. D. Thesis.Hydrogen peroxide (HP) based whitening products can damage enamel due to their pH and concentration. This in-vitro study investigates the effect of HP pH and concentration on selected enamel properties. In addition, combined effects of whitening/remineralisation and subsequent resistance to simulated dietary erosion and staining were investigated. Polished bovine enamel samples were treated with 6, 20, 40wt.% HP at pH 5, 7 and 9, for 2 hours daily for ten days. Samples were stored in artificial saliva at 37C before and after treatment. Whitening/remineralisation investigations were performed using 6wt.% HP in combination with either casein phosphopeptide–amorphous calcium phosphate (CPP-ACP) or nanohydroxyapatite (nHA). Samples were then subjected to simulated dietary staining using coffee and erosion using 0.3% citric acid (pH3.8). Measurements of enamel roughness (Ra), hardness (HV), and colour change (E) were made before and after treatment using atomic force microscopy, micro-hardness testing, and spectrophotometry. Mineral loss and qualitative surface evaluations were undertaken using energy dispersive x-ray spectroscopy (EDX) and scanning electron microscopy (SEM), respectively, after treatment. As HP concentration increased and pH decreased there was a statistically significant increase in E (P<0.05). Greatest increase in Ra and decrease in HV occurred in enamel treated with pH9 40% HP. Remineralisation did not significantly affect E, Ra, and HV of whitened enamel. CPP-ACP was effective in preventing statistically significant changes in Ra and HV values after erosive cycling. Enamel treated with nHA exhibited the greatest dietary stain uptake. No significant changes in enamel Ca, C, and P occurred after whitening, remineralisation, and erosion. SEM images revealed distinct surface changes mostly in pH9 and nHA treated samples. All whitened specimens exhibited significantly greater colour change than the control group. Neutral HP caused the least damage to whitened enamel while producing a satisfactory whitening effect. Remineralising agents did not reduce whitening side effects, however, CPPACP prevented significant Ra and HV changes after dietary erosion.College of Dentistry-Princess Nourah bint Abdulrahman Universit

Assessing the Role of Foreign Labour on Saudi Labour Unemployment in Saudi Arabia

Saudi labour unemployment is a very serious issue in Saudi Arabia which is further increasing with over dependence on foreign labour. This study empirically investigates this issue by employing ARDL cointegration technique on a sample period of 1980-2015. Our estimates suggest that foreign labour, wage rate and female participation are responsible for an increasing Saudi labour unemployment. On the other hand, number of graduates and government social security benefits are helping in combating Saudi labour unemployment. Therefore, our study recommends the Saudi government to control foreign labour inflows up to some reasonable limit, to rationalize the minimum wage rate and to increase spending on education and social security benefits. Social Security Benefits; Cointegratio

Green Human Resource Management, Financial Markets and Pollution Nexus in Saudi Arabia

Financial markets play an important role in accelerating the economic activities in any country but it may also harm environment if financial funds are invested in the project which are environment friendly. Further, Green Human Resource Management (GHRM) may help in reducing Co2 emissions.  This paper examines the influences of Financial Market Development (FMD) and GHRM on the pollution of Saudi Arabia. We explore this by using cointegration on time-series of 1971-2016. Results of this study corroborate that FMD and Economic Growth (EG) are positively contributing in CO2 emissions and GHRM is helping in reducing. We recommend the financial sector to provide concessional loans to the projects which are using clean energy technology and GHRM needs attention to support clean environment. Keywords: Financial Market Development; Co2 Emissions; Economic Growth  JEL Classifications: D53; Q53; O4

A conceptual examination about the correlates of psychological capital (PsyCap) among the Saudi Arabian workforce

Psychological capital (PsyCap), which is considered a higher-order construct, is composed of hope, efficacy, optimism, and resilience. The importance of PsyCap stems from the fact that it has the propensity to motivate individuals in their accomplishment of organizational tasks and goals. The concept is related to many behavioral concepts including: subjective well-being, social capital, employee engagement, and emotional intelligence. The majority of the research literature on PsyCap has originated from the West, and limited literature exists about its antecedents and consequences among the Saudi population. Studies undertaken in Saudi Arabia must take into account unique cultural aspects. The present work attempts to identify the contribution that could emerge from the relationship of PsyCap, with constructs like subjective well-being, social capital, and employee engagement, considered through the prism of culture. It also recognizes the influence of, and upon, the external environment. Going beyond the replication of earlier studies, the present work considers the constructs to have a yin-yang relationship. The study presented a model of comprehensive framework emerging from the relevant literature to bring out the complex connections between PsyCap and other constructs. It also emphasized the importance of culture on the identified constructs, and its implication on contribution and performance. The proposed framework needs to be further tested by academics, researchers, and practitioners to confirm its practical implications in industry

Evaluation of inhaled nitric oxide (iNO) treatment for moderate-to-severe ARDS in critically ill patients with COVID-19: A multicenter cohort study

Background: Inhaled nitric oxide (iNO) is used as rescue therapy in patients with refractory hypoxemia due to severe COVID-19 acute respiratory distress syndrome (ARDS) despite the recommendation against the use of this treatment. To date, the effect of iNO on the clinical outcomes of critically ill COVID-19 patients with moderate-to-severe ARDS remains arguable. Therefore, this study aimed to evaluate the use of iNO in critically ill COVID-19 patients with moderate-to-severe ARDS. Methods: This multicenter, retrospective cohort study included critically ill adult patients with confirmed COVID-19 treated from March 01, 2020, until July 31, 2021. Eligible patients with moderate-to-severe ARDS were subsequently categorized into two groups based on inhaled nitric oxide (iNO) use throughout their ICU stay. The primary endpoint was the improvement in oxygenation parameters 24 h after iNO use. Other outcomes were considered secondary. Propensity score matching (1:2) was used based on the predefined criteria. Results: A total of 1598 patients were screened, and 815 were included based on the eligibility criteria. Among them, 210 patients were matched based on predefined criteria. Oxygenation parameters (PaO2, FiO2 requirement, P/F ratio, oxygenation index) were significantly improved 24 h after iNO administration within a median of six days of ICU admission. However, the risk of 30-day and in-hospital mortality were found to be similar between the two groups (HR: 1.18; 95% CI: 0.77, 1.82; p = 0.45 and HR: 1.40; 95% CI: 0.94, 2.11; p= 0.10, respectively). On the other hand, ventilator-free days (VFDs) were significantly fewer, and ICU and hospital LOS were significantly longer in the iNO group. In addition, patients who received iNO had higher odds of acute kidney injury (AKI) (OR (95% CI): 2.35 (1.30, 4.26), p value = 0.005) and hospital/ventilator-acquired pneumonia (OR (95% CI): 3.2 (1.76, 5.83), p value = 0.001). Conclusion: In critically ill COVID-19 patients with moderate-to-severe ARDS, iNO rescue therapy is associated with improved oxygenation parameters but no mortality benefits. Moreover, iNO use is associated with higher odds of AKI, pneumonia, longer LOS, and fewer VFDs

A Conceptual Examination about the Correlates of Psychological Capital (PsyCap) among the Saudi Arabian Workforce

Psychological capital (PsyCap), which is considered a higher-order construct, is composed of hope, efficacy, optimism, and resilience. The importance of PsyCap stems from the fact that it has the propensity to motivate individuals in their accomplishment of organizational tasks and goals. The concept is related to many behavioral concepts including: subjective well-being, social capital, employee engagement, and emotional intelligence. The majority of the research literature on PsyCap has originated from the West, and limited literature exists about its antecedents and consequences among the Saudi population. Studies undertaken in Saudi Arabia must take into account unique cultural aspects. The present work attempts to identify the contribution that could emerge from the relationship of PsyCap, with constructs like subjective well-being, social capital, and employee engagement, considered through the prism of culture. It also recognizes the influence of, and upon, the external environment. Going beyond the replication of earlier studies, the present work considers the constructs to have a yin-yang relationship. The study presented a model of comprehensive framework emerging from the relevant literature to bring out the complex connections between PsyCap and other constructs. It also emphasized the importance of culture on the identified constructs, and its implication on contribution and performance. The proposed framework needs to be further tested by academics, researchers, and practitioners to confirm its practical implications in industry

Ultrasound-guided continuous spinal anesthesia for cesarean section in a parturient with scoliosis corrected with harrington's rod surgery

With rapid improvement in healthcare in Saudi Arabia, increasing number of women with surgically corrected kyphoscoliosis are likely to present for cesarean section (CS) or vaginal delivery requiring anesthesia or analgesia. Despite the surgical correction, these patients have poor cardiopulmonary reserves which increase the risks associated with general anesthesia. Whereas altered vertebral anatomy from previous surgery and the presence of metal work in spine make performing of regional anesthesia (RA) difficult and unpredictable, we report anesthetic management of such a patient who underwent CS using continuous spinal anesthesia technique. Challenges of placement of a spinal catheter in such a patient are discussed, and use of ultrasonography to circumnavigate these challenges is described. We propose that ultrasound can prove extremely valuable in performing of RA in patients with surgically corrected kyphoscoliosis. We could not find a similar case report from Saudi Arabia in the published literature

Impact of Acute Eccentric versus Concentric Running on Exercise-Induced Fat Oxidation and Postexercise Physical Activity in Untrained Men

Introduction. This study aimed at comparing the rate of exercise-induced fat oxidation and postexercise free-living physical activity after constant-load flat running (FR) and downhill running (DHR) bouts at an intensity that elicited maximal fat oxidation. Methods. Participants were 11 healthy untrained men (mean age 25.6±3.3 years; VO2max39.11±8.05 ml/kg/min). The study included four visits. The first two visits determined the intensity of maximal fat oxidation during incremental FR and DHR tests. The second two visits involved constant-load FR or DHR at the intensity that elicited maximal fat oxidation in a counterbalanced order separated by two weeks. Gas exchange analysis was used to measure substrate oxidation during all exercise sessions. Sedentary time and physical activity were measured using ActiGraph triaxial accelerometers for three days including the day of exercise tests (the second day). Results. During the incremental exercise tests, fat oxidation was significantly greater during the first stage of FR (P<0.05) but started to increase during the fourth stage of DHR, although this did not reach significance. Of the 11 participants, 7 had greater fat oxidation during DHR. During continuous constant-load running, fat oxidation was higher during DHR than FR but at only two stages was either significant or borderline significant, and the time/group interaction was not significant. There was no significant effect on sedentary time of time/group interaction (P=0.769), but there was a significant effect of time (P=0.005), and there was no significant effect on total physical activity of time/group interaction (P=0.283) or time (P=0.602). Conclusion. Acute aerobic eccentric exercise at an intensity eliciting maximal fat oxidation enhanced exercise-induced fat oxidation without worsening postexercise free-living physical activity, indicating it could be a useful training modality in weight management programs