Cardiovascular disease research in Saudi Arabia: a bibliometric analysis

In the previous three decades, in Saudi Arabia, prevalence of cardiovascular diseases (CVD) has increased and the government has invested significantly in education, healthcare, and research. This study examined the research productivity trends and characterized the types and focus of the all CVD research studies from Saudi Arabia. Data were extracted from studies published up until December 2015 and indexed in the PubMed database. Study eligibility criteria included: (1) sample selected within Saudi Arabia, and (2) CVD or a risk factor for CVD as an outcome, or (3) patients with CVD as study participants. Bibliometric data and study characteristics were extracted from each study; examples include authorship (number, gender, affiliation), journal, publication year, study location, research design, sample size, sample type (general or patient), sample composition (male or female), and sampling strategy (random or non-random). Analysis included 295 studies that pertained to 19 types of CVD; the most common were coronary artery disease (18%), hypertension (16%), stroke (14%), peripheral artery disease (11%), and congenital heart disease (10%). In the past 30 years, the overall productivity, use of a hypothesis-testing design (i.e. case–control, cohort, or trial), international collaborations, and funding increased incrementally. The experimental design constituted only 3% of all studies and less than 10% of the hypothesis-testing design studies. The scientific literature from Saudi Arabia addressed many of the CVD types. However, there were very few experimental studies conducted to date. Funding agencies should consider patronizing more studies with a hypothesis-testing design.     

Automatic analysis of human posture equilibrium using empirical mode decomposition

The present study proposes a new approach for the assessment of the human balance control. This approach is based on the decomposition of the center of pressure displacement using empirical mode decomposition (EMD) that provides an effective time-frequency analysis of non-stationary signals. Twenty-eight healthy subjects performed quiet standing in four conditions—feet apart/together with respect to eyes open/closed—while recording the stabilometric signals in the anteroposterior (AP) and mediolateral (ML) directions. The EMD method decomposes each stabilometric signal into several subsignals called intrinsic mode functions (IMFs). Stabilogram-diffusion analysis technique is applied to generate the diffusion curve of each IMF signal. Each diffusion curve is modeled as a second-order system and provides representative features, such as the gain parameter. Analysis of the gain parameter shows the major effect of visual input and feet conditions on the strategy to control/stabilize the balance. Significant differences were found between young and elderly, and between women and men. In addition, the impact of feet position seems to be higher in ML direction than in AP direction.     

Failure Investigation of Cracks in Bolted Flange

Cracks were observed on the outer diameter of the bolted flanges of a number of large control valves in high temperature service. An investigation was launched to determine the cause of cracking and propose corrective action. Metallurgical failure analysis and finite element analysis techniques were used to investigate the fracture, and concluded that the failures occurred due to thermal fatigue. A structural assessment performed on a cracked flange concluded that the cracks do not have an adverse effect on the integrity of the flange and it was concluded that the cracked flanges could be safely returned to service.     

Ontogeny of the testicular excurrent duct system of male Japanese quail (Coturnix japonica): A histological,ultrastructural, and histometric study

The testicular excurrent duct system undergoes several physiological and morphological changes during the reproductive stage or breeding season in mammals, birds, and reptiles. Studies on normal age-related histomorphological changes in the excurrent duct system of Japanese quails (Coturnix japonica) remain unreported, despite the extensive use of this bird as an avian model in research studies. The current study investigated the histological, ultrastructural, and histometric changes in the testicular excurrent duct system of the Japanese quail during three reproductive stages, namely prepubertal, pubertal, and adult. Simple squamous to low cuboidal cells formed the epithelia of the rete testis in prepubertal and pubertal birds, while in adult birds the lining was low cuboidal to cuboidal. In pubertal and adult birds, the nonciliated Type I epithelial cells of the proximal efferent duct displayed a subapical endocytotic apparatus comprising coated pits, coated apical tubules, and endosomes. There was a significant increase (p ≤ .001) in epithelial heights of all ducts of the excurrent duct system in the mature, sexually active, adult birds when compared to the other age groups. The luminal and tubular diameters, and the cross-sectional areas of efferent ducts and the epididymal duct unit increased significantly (p ≤ .001) with age. It is concluded that the morphology and morphometry of the excurrent ducts of the testis of the Japanese quail change as birds mature.     

Thermodynamic screening of suitable oxygen carriers for a three reactor chemical looping reforming system

Hydrogen (H₂) production by using a three reactor chemical looping reforming (TRCLR) technology is an innovative process which utilizes fossil fuels as feed stocks. This process occurs in three steps by employing an oxygen carrier (OC), which is generally a transition metal. As the OC plays an important role, its selection should be done after carefully considering the chemical and physical properties of the material. In this study, various candidate materials for use in a TRCLR process, with methane (CH₄) as a fuel stock, were investigated. The results show that the iron (Fe)- and molybdenum (Mo)-based OCs oxidize CH₄ completely in the FR at low temperatures. In terms of H₂ yield, tungsten (W)-based OCs produce the highest yield, ～3.9 mol-H₂/mol-CH₄. The equilibrium oxygen partial pressures and the solid circulation rates are the highest for Fe-based OCs. The oxygen carrying capacity of Fe-based OCs is relatively high while its price is low. Therefore, among the OCs investigated, Fe-based OCs were identified as the preferred OC option for a TRCLR process.     

Hydrous iron oxide for removal of inorganic contaminants in simulated stormwater: A batch sorption kinetics study

Urban stormwater runoff, which consists of inorganic and organic contaminants, is a major source of pollutants to receiving waters and therefore they need to be removed. Simultaneous removal of contaminants, Cd²⁺, Cu²⁺, Ni²⁺, Zn²⁺ (heavy metal cations), and SeO₄²⁻ (oxyanion) from a simulated stormwater by a hydrous ferric oxide (HFO) was studied in batch and column sorption experiments. In the batch experiment the rate of sorption of the ions was rapid at the beginning and reached equilibrium in approximately 300 min. The amounts of ions sorbed were proportionate to the respective initial concentration of the ions added to the HFO. Cluster analysis showed that all heavy metals had similar sorption behavior, whereas Se had a distinctly different sorption process. Of the three different kinetic models tested the pseudo-first order kinetic model fitted the data the best. The column experimental results beyond 180 min were consistent with those of the batch experiment that the removal efficiencies of the ions were in proportion to the ion concentration in the feed. Below 180 min, Cu appeared to be preferentially removed than Zn.     

Exploring the main building blocks of SOA method: SOA maturity model perspective

The most successful enterprises plan its SOA adoption process as a series of maturity stages, where each stage acts as a foundation for the next. Various SOA maturity models (SOAMMs) are available to judge the current level of SOA adoption maturity of an enterprise. However, only a very few models review the formal use of SOA methods in the maturity assessment process. In this work, the SOAMMs are evaluated in terms of how they assess the methodological aspects of SOA adoption at each level of maturity. Based on methodical features, we introduce a set of building blocks for different maturity levels to assist the method engineers in SOA method definition. Welke’s SOAMM is selected as a base model to derive maturity guidelines for SOA methods. This work establishes the role of SOAMM in realizing the true potential of SOA and discusses why CMMI models are inapplicable to assess SOA adoption maturity. The main intention of this work is to develop a conceptual framework that describes the building block of SOA methods at different levels of maturity, including their processes, tools and technologies, and sourcing mechanisms. We adopt a real case study to determine the maturity level of SOA methodology dimension and to demonstrate how SOA adoption maturity can be improved by focusing on the methodical building blocks identified.     

Can the dietary element content of virgin argan oils really be used for adulteration detection?

Levels of eight dietary elements were assessed by ICP-AES in virgin edible and beauty argan oil samples prepared from four remote locations of the argan forest, and over a three-year period. The data showed sufficiently little variability to assess that all argan oil samples present, in terms of dietary elements, a similar composition, independently from the tree location within the argan forest. Therefore, adulteration detection by trace element analysis in edible and beauty argan oil is a method that can be generalised.     

Epoxidized linolenic acid salts as multifunctional additives for the thermal stability of plasticized PVC

Calcium and zinc salts of epoxidized linolenic acid were synthesized and used as multifunctional additives, to minimize or prevent the reaction of epoxidized soybean oil (ESO) with liberated hydrochloric acid (HCl) during the thermal degradation of poly(vinyl chloride) (PVC) in particular. These metal epoxy salts were incorporated as thermal stabilizers for both diisodecyl phthalate and ESO–plasticized PVC blends that underwent thermal degradation studies at 170°C. The overall performance of these metal epoxy salts was examined by thermal gravimetric analysis and visual color retention of the PVC blends. The weight loss profiles of the metal salt stabilized PVC were comparable to those of blends containing metal stearates. There were, however, vast improvements in color retention of the plasticized PVC using these novel additives. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41736.