Effect of condensation methods on mechanical and physical properties of restorative composites

OBJECTIVE: To evaluate the effect of different condensation techniques on their flexural strength (FS) and compressive strength (CS) of different composite-resin restoration, to evaluate the effect of different condensation techniques and different curing durations on the level of cure of different composite resins at different depths. METHODS: Three manipulation instruments were tested: SonicFill (Kavo), ET 3000 (Brasseler) and Hand Condenser. Two different composite-resins were tested: Filtek Supreme Ultra (3M ESPE), SonicFill (Kerr). For compressive strength (CS), Cylinder-shaped specimens (N=10/group) measuring 4×6 mm were prepared. For flexural strength (FS), rectangular bars measuring 2×2×25 mm (N=10/group) were prepared. For level of cure, Cylinder-shaped specimens (N=27/ each composite) measuring 4×6 mm formed in Teflon molds and cured for three light curing durations (10, 20, 40 seconds) photocured with Bluephase 16i (ivoclar vivadent) that generate light intensity of 1350 mW/cm2 were prepared. All specimens were stored in water at 37 C° for 24 hours prior to testing. Specimens were tested for the flexural and compressive strength in an Instron machine. Vickers microhardness Test (Micromet 2003, Buehler) for the level of cure. Measurements were taken at 6 different depth levels from the top: 0.1, 2, 3, 4, 5 and 6 mm. Four indentations were recorded at each level. A total of 24 measurements for the level of cure were taken for each specimen. Data were analyzed using ANOVA and multiple comparison tests. RESULTS: Two-way ANOVA indicated a significant difference in the compressive strength between the two types of composites and the three different condensation techniques (P0.05). Moreover, this study investigated the effect of different condensation techniques and curing duration on the increase in the microhardness of composites and significance was recorded at different depth levels of the composite specimens (p value<0.05). CONCLUSIONS: The following were drawn: • The type of composite can increase significantly the material’s compressive strength and flexural strength. While the condensation techniques significantly increases only the compressive strength. • Curing time had significant effects on the microhardness of both composites (P< 0.0001). The condensing method had significant effects on the microhardness of SonicFillTM composite (P= 0.0001), but had no significant effects on the microhardness of Filtek Supreme Ultra composite (P= 0.1111).2019-09-26T00:00:00

معوقات تحقيق المعلِّمين لمبدأ مراعاة الفروق الفرديّة بين التّلاميذ من وجهة نظرهم دراسة ميدانية في مدارس الحلقة الأولى في مدينة اللّاذقية

هدفَ البحث إلى تعرّف معوقات تحقيق المعلِّمين لمبدأ مراعاة الفروق الفرديّة بين التّلاميذ من وجهة نظرهم, وفيما إذا تختلف وجهات نظر المعلِّمين حول هذه المعوقات باختلاف متغيّرات (المؤهِّل العلمي, والخبرة في التّعليم, ونوع المدرسة, ومستوى الصّف الدِّراسي). لتحقيق أهداف البحث؛ أعدّت الباحثة استبانة موجّهة إلى المعلِّمين في مدارس مدينة اللاذقية, تشمل (42) بنداً, موزّعاً إلى مجالات: معوّقات تتعلّق بالبيئة المدرسية, ومعوّقات تتعلّق بالعملية التّعليمية, ومعوقات تتعلّق بالمعلِّم. طُبّقت الاستبانة على عيّنة عشوائية مؤلّفة من (178) معلِّماً ومعلِّمةً وكان المنهج وصفي. أظهرت نتائج البحث أن أكثر المعوقات التي تعيق المعلِّم عن تحقيق مبدأ مراعاة الفروق الفرديّة من وجهة نظره هي: المعوقات المتعلّقة به, تليها المعوقات المتعلّقة بالعملية التّعليمية, ثمّ المتعلّقة بالبيئة المدرسية. وأبرز هذه المعوقات هي كثرة الأعباء التّربوية والتّعليمية المطلوب تحقيقها ضمن وقت محدد. ولم تُظهر النتائج وجود فروق في وجهات نظر المعلِّمين حول المعوقات التي تعيقهم عن تحقيق مبدأ مراعاة الفروق الفرديّة, تبعاً لمتغيّرات: المؤهِّل العلمي والخبرة في التّعليم ومستوى الصّف الدِّراسي, بينما أظهرت وجود فروق في وجهات نظرهم تبعاً لمتغير نوع المدرسة (لصالح المدارس العامّة)

Exposure Assessment of Aflatoxin B1 through Consumption of Rice in the United Arab Emirates

Rice is one of the most consumed staple foods worldwide and a major part of the diet for half of the global population. Being primarily cultivated in countries with warm and humid environments increases rice’s susceptibility for mycotoxins contamination, especially the hepatotoxic and carcinogenic aflatoxin B1 (AFB1). Since no study was published before on the exposure to AFB1 from consuming rice in the UAE, our study aims to assess the levels of AFB1 in rice marketed in the country and determine the estimated daily exposure of the population for this carcinogenic metabolite and its associated liver cancer risk. All white, brown, and parboiled rice brands available in the retail markets in the UAE were procured twice. Using an enzyme-linked immunosorbent assay (ELISA) method, AFB1 was detected in 48 out of 128 rice samples (38%). The average contamination ± standard deviation of AFB1 among positive samples (above the detection limit) was found to be 1.66 ± 0.89 μg/kg, ranging from 1 μg/kg (detection limit) to 4.69 μg/kg. The contamination level in all the samples was below the limit set by the Gulf Cooperation Council Standardization Organization (≤5 μg/kg), while 10 (20.8%) of the positive samples had a contamination level above the maximum limit set by the European Union (≥2 μg/kg). The moisture content in all the assessed samples was ≤14%. Furthermore, there was a significant difference in AFB1 between samples in both collections (p-value = 0.043). However, the rice type, grain size, packing country, packing season, country of origin, collection season, and packing to purchasing time had no significant effect on AFB1. The calculated mean daily exposure level of the Emirati population to AFB1 from consuming rice was 4.83 ng/kg.This research was funded by Office of Research and Sponsored Programs, Abu Dhabi University, United Arab Emirates

Exposure to Ochratoxin A from Rice Consumption in Lebanon and United Arab Emirates: A Comparative Study

Our study aims to evaluate the ochratoxin A (OTA) in rice marketed in Lebanon and the United Arab Emirates (UAE), and to determine the exposure to OTA from rice consumption. All brands available in the market were collected twice (total number of collected samples: 105 and 127 in Lebanon and the UAE, respectively). Using ELISA, the OTA in 56 (53%) samples in Lebanon and 73 (58%) samples in the UAE were above the limit of quantification (0.8 μg/kg). The average concentrations of the positive samples ± standard deviations were 1.29 ± 0.32 and 1.40 ± 0.42 μg/kg in Lebanon and the UAE, respectively. Only one sample (1%) in Lebanon had a level at the borderline of the European Union (EU) limit, and two samples (1.6%) in the UAE had a level above the EU limit (5 μg/kg). The OTA in brown rice was higher than in white and parboiled rice for both countries, yet the difference was not significant. The packing season, packing country, and country of origin did not have any significant effects. The presence of a food safety certification resulted in lower OTA in the rice, but the difference was significant (p = 0.04) in the UAE only. Long grains had higher OTA than short grains, yet the difference was only significant in Lebanon (p = 0.046). The exposures were calculated as 1.27 ng/kg body weight/day in Lebanon and 1.42 ng/kg body weight/day in the UAE, and no health risk was observed for both the neoplastic and non-neoplastic effects.This research was funded by Abou Dhabi University, United Arab Emirates

Support for UNRWA's survival

The United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) provides life-saving humanitarian aid for 5·4 million Palestine refugees now entering their eighth decade of statelessness and conflict. About a third of Palestine refugees still live in 58 recognised camps. UNRWA operates 702 schools and 144 health centres, some of which are affected by the ongoing humanitarian disasters in Syria and the Gaza Strip. It has dramatically reduced the prevalence of infectious diseases, mortality, and illiteracy. Its social services include rebuilding infrastructure and homes that have been destroyed by conflict and providing cash assistance and micro-finance loans for Palestinians whose rights are curtailed and who are denied the right of return to their homeland

Effects of Morinda citrifolia L. fruit extract on diabetic retinopathy biomarkers in retinal cells in vitro

Diabetic retinopathy is a leading cause of vision loss. It has been correlated with increased oxidative stress and the activity of aldose reductase (AR). The aim of the present study was to evaluate the protective and therapeutic properties of Morinda citrifolia L. (known as noni) fruit extract, in human retinal pigment epithelial cells (ARPE-19) exposed to high glucose. ARPE-19 cell line was incubated in normal (5.5 mM) and high (45 mM) glucose for 5 days in the absence and presence of indicated doses of noni fruit extract (10 and 50 μg/ml). In another experiment ARPE-19 cell line was incubated in normal (5.5 mM) and high (45 mM) glucose for 4 days and then incubated with or without indicated doses of noni fruit extract (10 and 50 μg/ml) for 24 hours before termination of experiment. Cell viability was assessed by MTT assay. Aldose reducatase (AR), vascular endothelial growth factor (VEGF), and advanced glycation end products (AGEs) were determined by enzyme immunoassay (ELISA). Total glutathione (GSH), reactive oxygen species (ROS), and malondialdehyde (MDA) were also assessed. The results showed that GSH content was significantly decreased after the addition of high glucose concentration. The presence of noni fruit extract prevented the reduction and maintained the GSH at the level found in cells exposed to 5.5 mM glucose concentration. Moreover, the levels of ROS, AGEs and MDA were significantly increased (P<0.05) after high glucose exposure compared to cell exposed to 5.5 mM glucose. The presence of noni fruit extract had reduced and maintained the ROS, AGEs and MDA at the levels found in control cells. Notably, the high glucose condition led to a significantly increased of AR and VEGF as compared to control cells, and noni fruit extract prevented this increment. This study demonstrated that noni fruit extract could prevent high glucose–induced oxidative stress and VEGF secretion via inhibition of aldose reductase in human retinal pigment epithelial cells (ARPE-19). In addition, the results of this study indicated that noni fruit could be an ideal agent used for treatment and protection against biomarkers of diabetic retinopathy

The effect of combined exercises with digital communication technology in developing forms of correction and deception for junior specialists in handball

Handball players aged 13–15 years in the Middle Euphrates belonging to the Central Handball Federation were distributed according to the specialised centers in the governorates (Karbala, Babylon, and Qadisiyah), which numbered 90 players. The specialised centers affiliated to Qadisiyah Governorate numbered thirty players, and the number of players of the studied age was twenty-two players. The renewal in the methods of communication and presentation of skills in advance and the possibility of reviewing them during performance and freely left to the learner contributed positively to the development of the combinatorial capabilities and the studied skills; and that the process of blending in the exercises prepared by the researcher between the combinatorial abilities and the studied skills contributed greatly to the development of the combinatorial capabilities and the studied skills; and that accreditation In developing skills for young ages in combination with combinatorial abilities, it is the one that will have a great impact in the future as it depends on a very high level

دور استخدام البرمجة الخطية في ترشيد القرارات الإنتاجية - دراسة حالة شركة مدار للمنظفات في محافظة اللاذقية-

يهدف هذا البحث إلى بيان مدى أهمية استخدام نموذج البرمجة الخطية في عملية ترشيد القرارات الإنتاجية، وذلك نظراً للدور الكبير الذي يلعبه هذا النموذج في اتخاذ قرارات علمية ومنطقية لحل المشكلات التي يواجهها متخذو القرارات في الشركات، إذ يساعد هذا النموذج متخذ القرار على اختيار البديل الأفضل من بين مجموعة البدائل المتاحة لحل المشكلة التي تواجهه، مما ينعكس إيجابياً على عمل الشركة، ولتحقيق هذا الهدف تم صياغة نموذج البرمجة الخطية وحلَّه باستخدام برنامج QM WINDOWS ، ومن ثم إجراء تحليل الحساسية للنموذج، وقد توصل البحث إلى أن تطبيق نموذج البرمجة الخطية في شركة مدار للمنظفات قد أسهم بترشيد القرارات الإنتاجية، وذلك عن طريق الاستخدام الأمثل للموارد المتاحة، والاستغلال الأمثل للطاقة الإنتاجية في الشركة محل الدراسة، بالإضافة إلى زيادة كمية الإنتاج بمقدار (280.498) طن، وبالتالي أدى ذلك إلى تعظيم ربحية الشركة بمقدار (208158924) ل.س

دور استخدام البرمجة الخطية في ترشيد القرارات الإنتاجية - دراسة حالة شركة مدار للمنظفات في محافظة اللاذقية-

يهدف هذا البحث إلى بيان مدى أهمية استخدام نموذج البرمجة الخطية في عملية ترشيد القرارات الإنتاجية، وذلك نظراً للدور الكبير الذي يلعبه هذا النموذج في اتخاذ قرارات علمية ومنطقية لحل المشكلات التي يواجهها متخذو القرارات في الشركات، إذ يساعد هذا النموذج متخذ القرار على اختيار البديل الأفضل من بين مجموعة البدائل المتاحة لحل المشكلة التي تواجهه، مما ينعكس إيجابياً على عمل الشركة، ولتحقيق هذا الهدف تم صياغة نموذج البرمجة الخطية وحلَّه باستخدام برنامج QM WINDOWS ، ومن ثم إجراء تحليل الحساسية للنموذج، وقد توصل البحث إلى أن تطبيق نموذج البرمجة الخطية في شركة مدار للمنظفات قد أسهم بترشيد القرارات الإنتاجية، وذلك عن طريق الاستخدام الأمثل للموارد المتاحة، والاستغلال الأمثل للطاقة الإنتاجية في الشركة محل الدراسة، بالإضافة إلى زيادة كمية الإنتاج بمقدار (280.498) طن، وبالتالي أدى ذلك إلى تعظيم ربحية الشركة بمقدار (208158924) ل.س