Synthesis and evaluation of coastal and marine biodiversity spatial information in the United Arab Emirates for ecosystem-based management

The United Arab Emirates (UAE) host valuable coastal and marine biodiversity that is subjected to multiple pressures under extreme conditions. To mitigate impacts on marine ecosystems, the UAE protects almost 12% of its Exclusive Economic Zone. This study mapped and validated the distribution of key coastal and marine habitats, species and critical areas for their life cycle in the Gulf area of the UAE. We identified gaps in the current protection of these ecological features and assessed the quality of the data used. The overall dataset showed good data quality, but deficiencies in information for the coastline of the north-western emirates. The existing protected areas are inadequate to safeguard key ecological features such as mangroves and coastal lagoons. This study offers a solid basis to understand the spatial distribution and protection of marine biodiversity in the UAE. This information should be considered for implementing effective conservation planning and ecosystem-based management.

Domination of Filamentous Anoxygenic Phototrophic Bacteria and Prediction of Metabolic Pathways in Microbial Mats from the Hot Springs of Al Aridhah

Microbial mats in hot springs form a dynamic ecosystem and support the growth of diverse communities with broad-ranging metabolic capacity. In this study, we used 16S rRNA gene amplicon sequencing to analyse microbial communities in mat samples from two hot springs in Al Aridhah, Saudi Arabia. Putative metabolic pathways of the microbial communities were identified using phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt). Filamentous anoxygenic phototrophic bacteria associated with phylum Chloroflexi were abundant (> 50 %) in both hot springs at 48 °C. Chloroflexi were mainly represented by taxa Chloroflexus followed by Roseiflexus. Cyanobacteria of genus Arthrospira constituted 3.4 % of microbial mats. Heterotrophic microorganisms were mainly represented by Proteobacteria, Actinobacteria, Bacteroidetes, and Firmicutes. Archaea were detected at a lower relative abundance (< 1 %). Metabolic pathways associated with membrane transport, carbon fixation, methane metabolism, amino acid biosynthesis, and degradation of aromatic compounds were commonly found in microbial mats of both hot springs. In addition, pathways for production of secondary metabolites and antimicrobial compounds were predicted to be present in microbial mats. In conclusion, microbial communities in the hot springs of Al Aridhah were composed of diverse bacteria, with taxa of Chloroflexus being dominant.

Featuring dental education research: applying the principles of action research to improve teaching of dental prosthetics

This article focuses on educational research conducted at the newly merged UWC faculty of dentistry. The research emphasises the change in teaching methods employed to address the concerns experienced in teaching the new large classes as observed in the prosthetic techniques module. These educational interventions were conducted over 5 years and the study design included the principles of action research. Students were assisted in learning the theory of the practical procedures and the subsequent completion of these procedures with the accurate application of the theoretical concepts. Changes in the teaching methods enhanced students learning and successful translation of the theory into practical work. The active learning exercises incorporated into the teaching further motivated and assisted students with deep learning. The debates indicated that students know and accept the value of the module as part of their training.

Determining the dimensional stability, fracture toughness and flexural strength of light-cured acrylic resin custom tray material

Light-cured acrylic resin custom tray material is used in commercial dental laboratories but little evidence-based scientific information on its physical properties is available.

OBJECTIVES

This study investigates the dimensional stability of light-cured acrylic resin custom tray material and compares its fracture toughness and flexural strength to a chemically-cured acrylic material.

METHOD

For dimensional stability, 20 light-cured specimens were fabricated and measured 3 times at regular time intervals over 48 hours. Mean shrinkage was calculated for each time interval and the mean values were compared to the standard using the Wilcoxon Rank Sum test. A p-value of <0.05 was considered significant. For fracture toughness, 2 groups of 20 light-cured and chemically-cured acrylic materials with a single-edge notch were subjected to a compressive load using the 3-point bending technique. For flexural strength, 1 group (n=20) of each material was subjected to a compressive load using 3-point bending. The highest load before failure was used to calculate the fracture toughness and flexural strength. Differences in fracture toughness and flexural strength values between the 2 groups were compared using ANOVA testing. A p-value of <0.05 was considered significant. The chemically-cured group was accepted as the control group.

RESULTS

Compared to the standard, shrinkage was significant for all time intervals (p<0.05). The difference in shrinkage among time intervals was not significant (p>0.05). The fracture toughness and flexural strength were significantly higher for the light-cured material.

CONCLUSIONS

Trays made from light-cured acrylic resin can be used immediately following polymerization. The light-cured material is more resistant to bending and crack propagation than the chemically-cured type.

The use of light-cured acrylic resin for custom trays by undergraduate dental students: a survey

INTRODUCTION

It is unknown how the use of a light-cured acrylic resin is appreciated over the traditional chemically cured resins for the construction of custom trays in a teaching environment.

OBJECTIVE

To evaluate the acceptance of light-cured acrylic resin for custom trays by dental students.

METHOD

A questionnaire addressing the use and handling properties of both light-cured (Megatray, Megadent, Germany) and chemically-cured (Excel, Wright Health Group, UK) custom tray materials was distributed amongst undergraduate dental students of the University of the Western Cape.

RESULTS

Of a total of 196 dental students, 38 were absent on the day of the survey. Of the 158 questionnaires that were distributed and returned, 18 did not meet the inclusion criteria and 1 person chose not to participate. Of the 139 participating students, 98 were in 4th year, 41 in 5th year. With regards to the light-cured acrylic custom tray material, 77% used it most often, 64% said it saved time and 62 % said that it was easier to handle. Fifty two percent indicated that both types of materials should be taught in undergraduate training, 26% preferred the light-cured acrylic resin custom tray material, 20% suggested that only the light-cured resin be used and no one suggested the chemically-cured resin exclusively.

CONCLUSIONS

Most undergraduate students positively accepted the light-cured resin, but training in the use of both materials was recommended.

Tyrosinase inhibitory lignans from the methanol extract of the roots of Vitex negundo Linn. and their structure-activity relationship

Phytochemical investigation of the methanol extract of Vitex negundo afforded eight lignans; negundin A 1, negundin B 2, 6-hydroxy-4-(4-hydroxy-3-methoxy)-3-hydroxymethyl-7-methoxy-3,4-dihydro-2-naphthaledehyde 3, vitrofolal E 4, (+)-lyoniresinol 5, (+)-lyoniresinol-3alpha-O-beta-d-glucoside 6, (+)-(-)-pinoresinol 7, and (+)-diasyringaresinol 8. The structures of these compounds were elucidated unambiguously by spectroscopic methods including 1D and 2D NMR analysis and also by comparing experimental data with literature data. The tyrosinase inhibitory potency of these compounds has been evaluated and attempts to justify their structure-activity relationships have been made in the present work. The compound 5 was found to be the most potent (IC(50)=3.21 microM) while other compounds demonstrated moderate to potent inhibitions. It was found that the substitution of functional group(s) at C-2 and C-3 positions and the presence of the -CH(2)OH group plays a vital role in the potency of the compounds. The compound 5 can act as a potential lead molecule to develop new drugs for the treatment of hyperpigmentation associated with the high production of melanocytes.

Aesthetic clasp design for removable partial dentures: a literature review

Removable partial dentures (RPD) are an effective and affordable treatment option for partial edentulism. If the main reason for seeking treatment is the need for improved aesthetics, treatment should be geared towards achieving this goal. This article is the result of a literature study on aesthetic clasp design for the conventional RPD. In this context, the position of the clasp on the tooth, clasp types, clasp material and alternative methods of retention are reviewed. Although published in reputable journals, the authors report that many articles published on this subject are of a descriptive nature and lack scientific evidence. Therefore, clinicians are encouraged to be critical in their interpretation of literature and the application of published information in their clinical practices.

Analysis of histone deacetylase inhibitor, depsipeptide (FR901228), effect on multiple myeloma

Multiple myeloma (MM) is a neoplastic proliferation of plasma cells and remains an incurable disease because of the development of drug resistance. Histone deacytylase (HDAC) inhibitors are a new class of chemotherapeutic reagents that cause growth arrest and apoptosis of neoplastic cells. Depsipeptide, a new member of the HDAC inhibitors, was found to be safe in humans and has been shown to induce apoptosis in various cancers. In order to evaluate the effects of depsipeptide, a MM cell line, U266 [interleukin (IL)-6 dependent], was analysed for viability and apoptosis. The combined effect of depsipeptide with melphalan and changes in BCL-2 family proteins (BCL-2, BCL-XL, BAX and MCL-1) were also investigated. In addition, the RPMI 8226 cell line (IL-6 independent), and primary patient myeloma cells were also analysed for apoptosis after depsipeptide treatment. Depsipeptide induced apoptosis in both U266 and RPMI 8226 cell lines in a time- and dose-dependent fashion, and in primary patient myeloma cells. We also demonstrated that depsipeptide had an additive effect with melphalan (10 micromol/l). BCL-2, BCL-XL and MCL-1 showed decreased expression in depsipeptide-treated samples. Based on recent clinical trials demonstrating minimal clinical toxicity, our study supports the future clinical utilization of depsipeptide in the management of MM.

Prevalence of hypertension and sociodemographic characteristics of adult hypertensives in Riyadh City, Saudi Arabia

OBJECTIVES

To estimate the prevalence of hypertension in adults residing in Riyadh city and to study the sociodemographic characteristics of adult hypertensives.

DESIGN

Cross-sectional survey.

SETTING

Primary Health Care Centres (PHCCs) in Riyadh city selected by stratified random sampling, the subjects resident in each PHCC catchment area were selected by systematic sampling from their records in the PHCCs.

SUBJECTS AND METHODS

A total of 1394 adults aged 15 years and over were interviewed and examined during March 1993 to March 1994. The average of three measurements of blood pressure (BP) was taken to represent their current pressures. A subject is considered hypertensive if the average BP reading is 160/95 mm Hg or more, or is currently under treatment.

RESULTS

The total hypertensive subjects were 214 giving an overall prevalence of hypertension of 15.4%. Of these 157 (11.3%) subjects were known hypertensives and were under some form of treatment. On the other hand 57 (4.1%) other subjects were newly detected by the study. Hypertension (BP = 160/95 mm Hg or more) was significantly related to age, marriage, education, occupation and employment status and consanguinity. Male subjects had a higher prevalence of hypertension but the differences were not significant. Nationality and income were not related to high BP.

CONCLUSION

Hypertension is a problem among adults in Riyadh city. It is significantly related to some sociodemographic and family factors. About 27% of all hypertensives are not aware of their disease and more than 31% of known hypertensives are apparently not well controlled. There is a need for a programme to prevent and control hypertension in Riyadh city. Similar studies need to be done in other areas of the country to estimate the prevalence of hypertension and associated factors as prerequisites for any programme to control the disease.

Smoking behaviour and attitudes among adult Saudi nationals in Riyadh City, Saudi Arabia

OBJECTIVE

To measure the smoking behaviour and attitudes among Saudi adults residing in Riyadh City, the capital of the Kingdom of Saudi Arabia.

DESIGN

Cross-sectional survey.

SETTING AND SUBJECTS

Primary health care centres (PHCCs) in Riyadh City were selected by stratified random sampling. Subjects resident in each PHCC catchment area were selected by systematic sampling from their records in the PHCCs; 1534 adults aged 15 years and older were interviewed during January to April 1994.

MAIN OUTCOME MEASURES

Self-reported smoking prevalence; age of smoking initiation; daily cigarette consumption; duration of smoking; reasons for smoking, not smoking, and quitting smoking; intentions to smoke in the future; and attitudes toward various tobacco control measures.

RESULTS

25.3% of respondents were current smokers, 10.2% were ex-smokers, and 64.5% had never smoked. About 79% of all smokers started smoking between the ages of 15 and 30 years, and 19.5% before age 15. Significantly higher smoking prevalence and daily cigarette consumption were associated with being male, single, and being more highly educated. Relief of psychological tension, boredom, and imitating others were the most important reasons for smoking, whereas health and religious considerations were the most important reasons for not smoking among never-smokers, for quitting among ex-smokers, and for attempting to quit or thinking about quitting among current smokers. About 90% of all subjects thought that they would not smoke in the future. Physicians and religious men were identified as the most effective anti-smoking advocates by a much higher proportion of respondents (44%) than nurses, health educators, and teachers (each less than 5%). Health and religious education were generally cited as more effective in deterring smoking than tobacco control laws and policies.

CONCLUSIONS

Cigarette smoking is prevalent among Saudi adults in Riyadh, particularly males, most of whom begin to smoke rather early in life and continue for many years. Health and religious education should be the cornerstone for any organised tobacco control activities, which are urgently needed to combat the expected future epidemic of smoking-related health problems.

An internal criterion of test validity

It has been suggested that the procedures of construct validation include at least two distinct processes: one is the validation of the test for measuring a hypothesized construct and the other is the validation of the construct, i.e., its usefulness and significance as a part of a theoretical system. Factor analysis has been re-evaluated as a method for studying construct validity of new instruments in face of both theoretical and computational advances in the field of factor analysis. A numerical index of construct validity has been suggested to be the multiple correlation of the observed variables with the factor (hypothesized construct). The notion of universe of content, the limiting value of the multiple correlation when n → ∞, etc. have been shown to have important implications for the concept of construct validity. The usefulness of such a procedure for the study of content and predictive validities, item analysis, interpretation of scores and validation of psychological theories has been outlined.