Tunable Permittivity Sensors

This thesis presents a novel electric permittivity sensor based on Bleustein- Gulyaev (BG) waves; waves that propagate along the surface of shear-poled piezoelectric materials. BG waves couple electromagnetic and acoustic waves, thereby reducing the speed of electromagnetic propagation to near acoustic speeds. Exploiting this property allows the development of permittivity sensors that feature several orders of magnitude reduction in size and operating frequency. This releases the limitations of RF complexity while reducing cost considerably. It also makes the sensor attractive for biological applications, as opposed to RF sensors that are limited by the water relaxation phenomenon at frequencies beyond 4 GHz. To date, sensors that used BG waves were limited to sensing mechanical properties, such as viscosity and density, which exploited the acoustic component of the wave only. To our best knowledge, this is the first attempt to probe and sense an electrical property acoustically using BG-waves. Towards that end, the nonlinear partial differential equations governing an electromechanical BG wave resonator are formulated. The permittivity of the medium-under-test was found to influence the sensor eigenvalues, enabling the implementation of a frequency-shift permittivity sensor. We also find that the sensor sensitivity is enhanced by increasing bias voltage to drive the sensor into the nonlinear regime, but this is limited by electrical breakdown. Sensor prototypes were fabricated on PZT4 and LiNbO3 shear-poled substrates. A novel method to characterize shear-horizontal surface acoustic waves, SHSAW, using a 1D Laser Doppler Vibrometer was developed to test the sensors. The method was also shown to be able to estimate the in-plane displacement field decay rate into the substrate. This technique provides researchers with a quick and effective method for the characterization of SH-SAW. The resonator model was validated using this experimental method. A Vector Network Analyzer was employed to observe the shift in the fundamental natural frequency of the fabricated permittivity sensors in the presence of various media-under-test. Measurements show deterministic and repeatable frequency shifts in the natural frequency in the presence of ethanol and deionized water compared to that of the bare surface, thereby demonstrating the permittivity sensor

Dyslipidemia is the hallmark of the metabolic syndrome in postmenopausal women: Dyslipidemia in postmenopausal women

The incidence of cardiovascular diseases (CVD) increases after menopause and may be due to changes in the plasma lipid-lipoprotein levels that occur following menopausal transition. Physiological estrogen withdrawal during menopause plays a major role in abnormal lipid metabolism such as elevated low-density lipoprotein concentration. The aim of this study was to determine the relationship between dyslipidemia and the causative factors of metabolic syndrome in postmenopausal women. In this cross-sectional study, 290 postmenopausal Sudanese women were included. Lipid profiles were measured by spectrophotometer, estrogen hormone determined by ELISA, insulin resistance determined by HOMA-2 calculator and lipid accumulation product was calculated by the following equation (waist circumference in cm X triglyceride concentration in mM). The results revealed that total cholesterol, triglycerides, low-density lipoprotein levels and very low-density lipoprotein levels were significantly higher in the postmenopausal women with metabolic syndrome (MS) in comparison to those without the MS. Elevated total cholesterol levels were seen in 51.7 %, elevated triglycerides were seen in 49.7% and elevated low-density lipoprotein levels were seen in 29.3% whereas reduced high density lipoprotein levels were seen in 16.89% of the postmenopausal women. Total cholesterol, triglycerides and very low-density lipoprotein values showed a significant positive correlation with insulin resistance and lipid accumulation and a significant negative correlation with the estrogen hormone level. In addition, high density lipoproteins showed a significant negative correlation with lipid accumulation levels

Formulation and Characterization of Thymoquinone Bioadhesive Gel for Treatment of Chronic Gum Inflammation

The aim of study is to formulate Thymoquinone gel and investigate its effect in chronic periodontitis in terms of clinical periodontal parameters, anti-oxidant capacity and the levels of IL-1β in gingival crevicular fluid. different gelling agents (carbopol, hydroxyl propyl methyl cellulose and chitosan) were used for the development of TQ gel. The optimized gel formulation was used for the clinical study. The study was conducted on 68 subjects (25-58 years old). 48 patients were clinically diagnosed with moderate to severe chronic periodontitis. Patients were divided into three groups; Group I (24 patients): received non-surgical periodontal therapy and Thymoquinone-chitosan gel (0.1 % w/w), Group II (24 patients): received only non-surgical periodontal therapy and Group III: 20 healthy subjects (control group). All patients were evaluated for clinical parameters including plaque index (PI), gingival index (GI), probing depth (PD) and clinical attachment level (CAL).  The levels of IL-1β and total anti-oxidant capacity were recorded in gingival crevicular fluid at baseline (prior to treatment) and at weeks 4 and 12 after treatment. The results showed that combination of non-surgical periodontal therapy and Thmoquinone gel (group I)  exhibited statistically significant improvement in biochemical parameters compared to non-surgical periodontal therapy alone (group II). In conclusion we can say that the adjunctive use of thymoquinone gel with non-surgical periodontal therapy improves the biochemical parameters accompanied with chronic periodontitits significantly after 4 weeks only

Arabian Partridge Abundance and Limiting Factors at the Northern Boundary of Its Range

The Arabian Partridge (Alectoris melanocephala), is an endemic bird species of the Arabian Desert that lives in groups and inhabits rocky hillsides with patchy vegetation. Throughout their range, Arabian Partridges contend with hunting and habitat destruction, factors that may limit their distribution and abundance. Although the abundance of this species has been assumed to be stable, no actual estimate of its population size has been undertaken. We assessed the distribution and estimated the abundance of the Arabian Partridge at the northern boundary of its range in Saudi Arabia. The estimated density and abundance of the Arabian Partridge in Harrat Uwayrid Biosphere Reserve was 25.6 (6.16 SE) birds/km2 and ~118 individuals, respectively, with higher numbers of individuals in less disturbed sites and near rocky outcrops and hillsides. In sites where hunting occurred, as indicated by the presence of hunting shelters, partridge numbers were extremely low or absent. Our study provides the first quantitative assessment of the Arabian Partridge at the northern limit of its range and highlights the need to reduce threats from hunting, livestock grazing, and feral donkeys and to undertake conservation measures to mitigate factors associated with partridge decline

A Lightweight Network for Real-Time Rain Streaks and Rain Accumulation Removal from Single Images Captured by AVs

In autonomous driving, object detection is considered a base step to many subsequent processes. However, object detection is challenged by loss in visibility caused by rain. Rainfall occurs in two main forms, which are streaks and streaks accumulations. Each degradation type imposes different effect on the captured videos; therefore, they cannot be mitigated in the same way. We propose a lightweight network which mitigates both types of rain degradation in real-time, without negatively affecting the object-detection task. The proposed network consists of two different modules which are used progressively. The first one is a progressive ResNet for rain streaks removal, while the second one is a transmission-guided lightweight network for rain streak accumulation removal. The network has been tested on synthetic and real rainy datasets and has been compared with state-of-the-art (SOTA) networks. Additionally, time performance evaluation has been performed to ensure real-time performance. Finally, the effect of the developed deraining network has been tested on YOLO object-detection network. The proposed network exceeded SOTA by 1.12 dB in PSNR on the average result of multiple synthetic datasets with 2.29× speedup. Finally, it can be observed that the inclusion of different lightweight stages works favorably for real-time applications and could be updated to mitigate different degradation factors such as snow and sun blare

Apium Graveolens and Rosmarinus Officinalis Protect from Liver Toxicity Induced by Sodium Valproate in Rats and Potentiate its Anticonvulsant Activity on Pentylenetetrazol-Treated Rats

Hepatic injury is a dose-limiting side effect of sodium valproate (VPA), a common used drug in the management of numerous nurological disorders, including epilepsy. The present study was designed to investigate the effect of Apium Grafionalies (AG) and Rosmarinus officinalis (RO) against VPA-induced liver injury. Hepatic toxicity was induced by the administration of VPA (500 mg/kg/day) once daily for a period of 7 days. The hepatoprotective group received ethanolic extracts of AG and RO (200 mg/kg/day) for 7 days prior to VPA treatment for seven days. VPA liver toxicity was evaluated based on serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities and, albumin, and total protein levels as well as by histology. Serum ALT and AST activities were elevated and albumin and total protein levels were depleted. Histopathological changes in liver such as fatty degeneration and focal necrosis were associated with significant increase in TUNEL-positive cells and P53 protein in immunohistochemical study indicating the presence of DNA fragmentation. This biochemical and histological changes were associated with increased oxidative stress damage as evidenced by increases in protein carbonyl (P.Carbonyl) and decreases in total antioxidant capacity (TAC) in liver. These biochemical and histological disturbances were effectively attenuated on pretreatment with either AG or RO extract, which normalized P.Carbonyl and TAC and attenuated histopathological changes induced by VPA. These observations shed light on the hepatoprotective actions of both AG and RO extracts against experimental VPA toxicity. AG was characterized for its apigenin content while RO was characterized for its rosmarinic acid and carnazol contents. Besides, in a pentylenetetrazole (PTZ) rat clonic convulsion model, pretreatment with AG and RO (200 mg/kg) before VPA protected against PTZ-induced convulsion, where it delayed the onset of clonic convulsion in PTZ treated rats

HIV case reporting and HIV treatment outcomes in Qatar

AimThe aim of the paper is to provide an overview of available HIV case reporting and treatment data for in Qatar for the period 2015–2020.MethodsHIV case reporting data were analyzed by sex and mode of transmission. To construct HIV care continuum from the data available, we obtained information on the total number of HIV diagnosed patients on antiretroviral treatment (ART) between January 1st 2015 and December 31st 2020, number of patients on ART who had an HIV viral load test and the number who were virally suppressed (defined as having the viral load of less than 1,000 copies/mL).ResultsA total of 515 HIV cases were reported to the Ministry of Public Health since beginning of reporting in 1986, and that included Qatari nationals and expatriate residents diagnosed in Qatar. There was an increase in the annual number of newly reported HIV cases from 16 cases in 2015 (of these, 14 were males) to 58 cases in 2020 (of these, 54 were males). The total number of HIV diagnosed people on ART increased from 99 in 2015 to 213 in 2020. During 2020 the overall viral load testing coverage and viral load suppression among those tested for viral load in men were 72.5% and 93.1%, respectively, while in women these values were 60.4% and 84.4%, respectively.ConclusionDue to increase in newly reported HIV cases, there is a need to develop an effective HIV strategic information system in Qatar and data-driven and targeted national HIV response

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Pension Accounting and Disclosure Reforms: Determinants and Consequences

Accounting standard-setting bodies and regulators have imposed requirements to improve pension accounting regulations and disclosure practices due to the importance and materiality of defined benefit pension plans. In particular, IAS 19R was recently amended to address the excessive risk-taking in pension plan investments. In addition, academics, and practitioners have stressed the importance of high-quality and transparent disclosure to improve the usefulness of information aimed at stakeholders. Drawing on theories such as agency theory, positive accounting theory, stakeholder salience theory, collective bargaining theory, signalling theory, and behavioural decision theory, the study addresses three key research questions along two axes: the implications of accounting regulations on pension investment decisions followed respectively by the determinants and consequences of pension disclosure practices. Therefore, this study first examines the economic consequences of IAS 19R on pension asset allocations and the moderating role of firm financial distress by relying on a sample of European listed firms affected by IAS 19R, compared to a control group of US firms that share similar firms’ characteristics but are unaffected by the standard between 2009 and 2014. Second, by relying on an automated content analysis approach to evaluate the specificity of defined benefit pension plan information for 119 FTSE350 listed firms over the period 2017 to 2019, the study examines whether a firm’s unionisation level has an impact on the quality (specificity) of pension information in the strategic report and whether this relationship is moderated by the level of cash holdings. Thirdly, the study considers whether the pension information specificity affects credit rating agencies' (CRAs) decisions. It also examines whether and how pension information specificity influences credit rating disagreement between CRAs. Respectively, the analysis reveals firms shifted out of equities during the post-IAS 19R period, especially if they were in financial distress. Some firms allocated pension plans to other asset classes, but the types of asset classes being re-allocated varied across countries, suggesting that the economic consequences of IAS 19R on pension asset allocations are influenced by firms’ financial health and the country’s pension welfare system. Subsequently, the study found that while the strategic report became lengthier, there was a decline in the quality (specificity) of pension information. However, a higher unionisation rate improved the quality of pension disclosure, suggesting that trade unions are seen as salient stakeholders who can influence firms' disclosure strategies; especially if firms hold high cash levels that enhance employees-employers trust. Finally, there is a significantly negative association between the level of pension information specificity in the firm's strategic report and credit rating decisions, suggesting that higher pension information specificity is associated with a lower credit rating or downgrading. There is also evidence that greater pension information specificity reduces rating disagreement, particularly when the ratings are two notches or higher. Overall, standard-setting bodies and practitioners should consider the role of the dimension of social welfare characteristics in the allocation of pension plans to different asset classes, which may result in shifting rather than mitigating pension risk within the pension plan. Furthermore, regulators should pay attention to firms' disclosure strategies when they face salient stakeholders to accommodate their demands which may cause inconsistency in reporting behaviour resulting in a lack of information transparency to all stakeholders