Low attenuation microwave waveguides

PhDAn investigation of the dispersion and attenuation characteristics of cylindrical structures supporting guided electromagnetic waves with low attenuation is described. The object of the investigation is to understand how the cross-sectional shape and the nature of the boundary conditions affects the propagation characteristics. Attention is directed towards structures supporting the least number of propagating modes under the conditions which yield low attenuation over a reasonable bandwidth. Elliptical waveguides with both smooth-walls and corrugated walls are studied in detail. This reveals errors in previous-theories which are corrected. Some aspects of corrugated rectangular and circular waveguides are considered. Potential low attenuation waveguides such as the dielectric lined and dielectric waveguides are evaluated

Propolis Modulates Inflammatory Mediators and Improves Histopathology in Male Rats with L-arginine-induced Acute Pancreatitis

ABSTRACT: Objectives: This study aimed to determine the effects of propolis on immune mediators and tissue histopathology in rats with L-arginine-induced acute pancreatitis (AP). Methods: This study was conducted at Imam Abdulrahman Bin Faisal University, Dammam, Saudia Arabia between September and November 2017. A total of 24 male albino Wistar rats were divided into three equal groups. Group one was the negative control, group two was the positive control (L-arginine-induced AP) and group three received treatment (L-arginineinduced AP and propolis). The rats in group three were treated with 100 mg/kg propolis for seven days after AP induction. Pancreatic tissue was evaluated histologically and levels of interleukin (IL)-6, IL-22 and IL-1β and tumour necrosis factor-alpha (TNF-α) were measured. Results: Propolis reduced the quanitity of proinflammatory molecules (TNF-α, IL-1β and IL-6) in group three compared to group two, significantly increased the overall anti-inflammatory effect of IL-22 (P <0.005) and reduced interstitial inflammation and neutrophil cell infiltration of the pancreatic tissues. Conclusion: Propolis may exert a therapeutic effect in AP. Further studies are required to demonstrate the mechanisms of propolis in AP.Keywords: Propolis; Arginine; Pancreatitis; Interleukins; Cytokinesis; Rats; Saudi Arabia

Determinants Contributing To The Primary Market Spread Of Securitization In Malaysia

During the year 1997, the Asian financial crisis disclosed the inherent weaknesses of the financial market in Asia. Organisations had an over-dependence to the banks as the primary sources of fund is one of the reasons why companies faced difficulty during the financial crisis. One of the factors that contributed to the financial crisis was that organizations failed to diversify their financing structure. It is to be noted that when organisations want to source for funds, they can either issue stocks, bonds or finance from banks locally or globally. Source capital from equity and borrowing through debt is considered difficult, expensive and will distort the financial leverage of the company. The development of securitization allows the organization to smooth up their cash flow by converting the illiquid assets into a liquid asset through a special purpose vehicle (SPV). SPV is a legally separated entity from the company or the holder of the assets. SPV can take the forms of either a trust, corporation or partnership set up just for the purchasing of the originator's assets. There are many literature pieces of research that regard the factors that contribute to the pricing of corporate bonds but there are few empirical studies on the determinants on securitization in Malaysia. In view of the increases of awareness of securitization, this paper intends to investigate the determinants contribute to the primary market spread of securitization in Malaysia. The primary market rate is the initial or first-time offer rate by the originator and issued by the SPV. The rate offered by the SPV is based on the underlying lease payment form the originator collection. This research applied regression analysis for the period from 2004 to 2014. The regression results show that three variables have negative and one positive relationship with the primary market spread. Thus, it can conclude that selective variables can act as an important influence to the primary market spread in helping the originators setting the competitive prices in securitization

Modeling An Islamic Student Financing Securitization

The study investigates developing an Islamic student financing securitization model based on sukuk structures. This study employs sample of descriptive, analytical, and comparative analyses utilized to discuss a novel framework of Islamic securitization through the different structures of sukuk wakalah derived from asset securitization. The result served to investigate the use of Islamic student financing securitization in a Shariah-compliant manner, which would be implementable in Malaysia. It emphasized the sukuk structures based on the wakeel principle, which indicated a situation where a wakeel or representative appointment was made to manage a project on the behalf of the sukuk holder. The findings of this study supported the economic benefits obtained in the form of lower overall financing costs through the use of securitization for student financing in higher education. This paper offers important implications specifically for the creation of sukuk structures and issuing a highly graded and marketable sukuk, which are compliant towards global Shariah principles. The paper fills the gap perceived within the existing literature of Islamic finance by showing Islamic securitization via sukuk as a viable source of funds potential utilizable in stabilizing the securities market. It can also pose as a solution for securing a sustainable funding

Factors Influencing Spread In Malaysia Securitization Market

The purpose of this paper is to propose a model to test the factors influencing on spread in Malaysia securitization market. An extension Vink’s model is tested and revalidated to determine and measure the factors influencing spread of securitized firms in Malaysia. The study consists firm characteristics and macroeconomic factors. Firm characteristic factors based on Vink’s model, such as Liquidity and Leverage. In addition, economic and market condition factors such as Interest and Inflation also maintain high impact to spread securitized firms. Ordinary Least square method, Panel data and multiple regression analysis are applied for the study period 2004-2012. The result shows two determinants influence or contribute to the primary market spread and are statistically significant in developing the securitization in Malaysia. It can be concluded that inflation and interest rate significantly contribute to the determinant of primary market spread. From four hypotheses, two hypotheses support that the determinants had a relationship with primary market spread. The result may become a model and benchmark for other ASEAN countries to be used as Malaysia resilient during subprime mortgage in 2008

Indoor air quality (IAQ) in educational institutions: a review on risks of poor IAQ, sampling strategies, and building-related health symptoms

Health and academic achievement of students from every level of education are affected by the provision of good Indoor Air Quality (IAQ) since the students spend more than 5 hours of a day in school on average. Hence, this paper discusses on issues related to IAQ studies in maintaining a healthy level in educational institution. The presence of indoor pollutants such as VOCs, CO2, and other hazardous elements were assessed in terms of its effects on students’ well-being and health. This paper also examines commonly reported health problems related to poor IAQ such as sick building syndrome (SBS) and asthma. Every measurements and consideration regarding IAQ provision comes with different techniques and strategies, which were highlighted regarding its relative importance and frequency of use by different researchers. The review suggested substitution of natural-based products for indoor cleaning agents and installation of air ventilation and purification systems for a more acceptable indoor air quality

Solid-State NMR Spectroscopy:Towards Structural Insights into Starch-Based Materials in the Food Industry

Solid-state NMR is a nondestructive and noninvasive technique used to study the chemical structure and dynamics of starch-based materials and to bridge the gap between structure–function relationships and industrial applications. The study of crystallinity, chemical modification, product blending, molecular packing, amylose–amylopectin ratio, end chain motion, and solvent–matrix interactions is essential for tailoring starch product properties to various applications. This article aims to provide a comprehensive and critical review of research characterizing starch-based materials using solid-state NMR, and to briefly introduce the most advanced and promising NMR strategies and hardware designs used to overcome the sensitivity and resolution issues involved in structure–function relationships

The global burden of adolescent and young adult cancer in 2019 : a systematic analysis for the Global Burden of Disease Study 2019

Background In estimating the global burden of cancer, adolescents and young adults with cancer are often overlooked, despite being a distinct subgroup with unique epidemiology, clinical care needs, and societal impact. Comprehensive estimates of the global cancer burden in adolescents and young adults (aged 15-39 years) are lacking. To address this gap, we analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, with a focus on the outcome of disability-adjusted life-years (DALYs), to inform global cancer control measures in adolescents and young adults. Methods Using the GBD 2019 methodology, international mortality data were collected from vital registration systems, verbal autopsies, and population-based cancer registry inputs modelled with mortality-to-incidence ratios (MIRs). Incidence was computed with mortality estimates and corresponding MIRs. Prevalence estimates were calculated using modelled survival and multiplied by disability weights to obtain years lived with disability (YLDs). Years of life lost (YLLs) were calculated as age-specific cancer deaths multiplied by the standard life expectancy at the age of death. The main outcome was DALYs (the sum of YLLs and YLDs). Estimates were presented globally and by Socio-demographic Index (SDI) quintiles (countries ranked and divided into five equal SDI groups), and all estimates were presented with corresponding 95% uncertainty intervals (UIs). For this analysis, we used the age range of 15-39 years to define adolescents and young adults. Findings There were 1.19 million (95% UI 1.11-1.28) incident cancer cases and 396 000 (370 000-425 000) deaths due to cancer among people aged 15-39 years worldwide in 2019. The highest age-standardised incidence rates occurred in high SDI (59.6 [54.5-65.7] per 100 000 person-years) and high-middle SDI countries (53.2 [48.8-57.9] per 100 000 person-years), while the highest age-standardised mortality rates were in low-middle SDI (14.2 [12.9-15.6] per 100 000 person-years) and middle SDI (13.6 [12.6-14.8] per 100 000 person-years) countries. In 2019, adolescent and young adult cancers contributed 23.5 million (21.9-25.2) DALYs to the global burden of disease, of which 2.7% (1.9-3.6) came from YLDs and 97.3% (96.4-98.1) from YLLs. Cancer was the fourth leading cause of death and tenth leading cause of DALYs in adolescents and young adults globally. Interpretation Adolescent and young adult cancers contributed substantially to the overall adolescent and young adult disease burden globally in 2019. These results provide new insights into the distribution and magnitude of the adolescent and young adult cancer burden around the world. With notable differences observed across SDI settings, these estimates can inform global and country-level cancer control efforts. Copyright (C) 2021 The Author(s). Published by Elsevier Ltd.Peer reviewe

The global burden of cancer attributable to risk factors, 2010-19 : a systematic analysis for the Global Burden of Disease Study 2019

Background Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. Methods The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk-outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. Findings Globally, in 2019, the risk factors included in this analysis accounted for 4.45 million (95% uncertainty interval 4.01-4.94) deaths and 105 million (95.0-116) DALYs for both sexes combined, representing 44.4% (41.3-48.4) of all cancer deaths and 42.0% (39.1-45.6) of all DALYs. There were 2.88 million (2.60-3.18) risk-attributable cancer deaths in males (50.6% [47.8-54.1] of all male cancer deaths) and 1.58 million (1.36-1.84) risk-attributable cancer deaths in females (36.3% [32.5-41.3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20.4% (12.6-28.4) and DALYs by 16.8% (8.8-25.0), with the greatest percentage increase in metabolic risks (34.7% [27.9-42.8] and 33.3% [25.8-42.0]). Interpretation The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.Peer reviewe