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Objectives. To assess participants' knowledge about HIV/AIDS and to identify the factors associated with HIV/AIDS in Sudan. Methods. Observational cross-sectional study carried out at Omdurman National Voluntary Counseling and Testing Centre, Sudan covered 870 participants. Sociodemographic data as well as information related to sexual behavior were collected. Results. Most of the respondents were knowledgeable about the true transmission modes for AIDS virus. Very few respondents knew someone infected with AIDS (4.5%), died of AIDS (8.1%), accepted to live with someone infected with AIDS (4.7%) or to work with someone infected with AIDS (2.1%). Regarding sexual behavior, 96.5% had reported their first sexual experience between 20 and 30 years, with 85.7% reporting one or two partners, and only 1.8% reported using condom. Multivariate logistic regression showed that circumcision, religion, marital status, age at first sex, number of sexual partners, education level, and misconception of knowledge are the main risk factors associated with HIV/AIDS. Conclusion. Our results showed that a number of diversity risk factors were associated with HIV/AIDS. It is unlikely that a holistic approach will be found to immediately change sexual-risk-relating behavior. Interventions including sustained educational programs, promotion of condom, and encouragement of voluntary testing and active involvement of the country's political and religious leaders will be needed to alleviate this problem.

oxide-based experimental silane primers enhance shear bond strength between resin composite and zirconia. Eur J Oral Sci 2019; 127: 570-576. © 2019 Eur J Oral SciDespite various mechanical and chemical surface-pretreatment methods, long-term bonding of resin composite to dental zirconia (ZrO 2 ) remains a major concern. In this study, graphene oxide (GO) sheets were infused into two commercially available primers and the enclosed mould shear bond strength (EM-SBS) of resin composite to ZrO 2 was evaluated. Twelve fully sintered ZrO 2 blanks were pretreated and randomly allocated to four groups according to the primers used: RelyX (RX); GO blended RelyX (RXGO); Monobond-S (MB); and GO blended Monobond-S (MBGO). The resin composite stubs were bonded onto the pretreated ZrO 2 surfaces and analysed at baseline and after storage in distilled water for 2 and 4 months. The experimental primers blended with GO sheets influenced the surface morphology, visualized as increased surface roughness, and slightly increased the water contact angle measurements. Moreover, the infusion of primers with GO increased the mass fraction (wt%) of carbon and oxygen. The highest EM-SBS values were found for RXGO, with mean (SD) EM-SBS values of 26.4 (3.7) MPa and 21.5 (5.1) MPa after 2 and 4 months of storage, respectively. Infusion of silane primers with nanometre-to micrometre-size GO sheets enhanced the SBS between resin composite and ZrO 2 .

The purpose of this laboratory study was to formulate and characterize the graphene oxide-poly(methyl methacrylate) resin composite with an intended use as bone cement. Graphene oxide was fabricated through ultrasonication route. The autopolymerization resin (Eco Cryl Cold, Protechno, Vilamalla Girona, Spain) was used to prepare the specimens of required dimensions for different testing parameters. The control group (C-group) was prepared as such. However, for GO1-group, 0.024 wt/wt.-% of graphene oxide was incorporated in a resin matrix and GO2-group was a composite with 0.048 wt/wt.-% of graphene oxide in a resin matrix. TEM examination of graphene oxide sheets demonstrated them in the range of ∼500 nm to ∼2 µm. The mechanical properties were characterized using three-point bending and wear resistance, while material properties were assessed through transmission electron microscope, scanning electron microscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, differential scanning calorimetry and thermo-gravimetric analysis. The results suggest that 0.024 wt/wt.-% and 0.048 wt/wt.-% of loading of GO have no effect on the physiochemical characteristics. However, thermal characteristics might slightly be improved. According to the analysis of variance results (p < 0.05, n = 5), wear resistance and bending strength of both GO1 and GO2 groups significantly improved compared to C-group. The bending strength of GO2 improved to 87.0 ± 7.2 MPa from 65.9 ± 11.5 MPa of C-group. Scanning electron microscopy examination of the fractured surface demonstrated granule like structure where the graphene oxide sheets might be covered inside PMMA. The use of GO-PMMA composites favorably enhances the mechanical properties of bone cement.

Background: University students might experience numerous sources of stress in their daily lives. Previous research has found that stress affects food selection patterns, but the effect might vary by country and sex. No previous study conducted in Saudi Arabia has assessed the association between stress and dietary habits among university students. Thus, this study aimed to examine the association between perceived stress and food selection patterns among undergraduate students by sex at King Saud University (KSU). Methods: A cross-sectional study of 400 students attending the College of Applied Medical Sciences in Riyadh, Saudi Arabia, was conducted. The self-administered questionnaire that was used consisted of three sections: sociodemographic, food frequency questionnaire, and Cohen's Perceived Stress Scale. Results: Approximately (59.0%) of the participants reported suffering from some level of stress, with more females (64.5%) experiencing stress than males (54.0%). The univariate analysis showed that under stress, more females (68.0%) reported eating more than usual than males (49.0%), while the percentage of respondents that reported eating less than usual was higher for females (23.0%) than that for males (31.0%). The McNemar test indicated that under stress, there was an increased preference for salty flavors, which was not associated with sex. Significantly more females (82.0%) than males (64.5%) reported preferring sweets under stress. More males reported preferring bitter and savory flavors than females. Under stress, females preferred homemade food, while males preferred takeout foods. More females (68.0%) reported losing control and overeating than males (49.0%). A logistic regression showed that for female students, perceived stress was associated with frequent consumption of sweets, cake/cookies, snacks and beverages and less frequent consumption of fruits and vegetables. For males, the consumption of fast food and meat was significantly positively associated with perceived stress. Conclusion: Perceived stress led to unhealthy changes in eating patterns in both sexes, as evidenced by reports of an increased preference for sweets, snacks and cake/cookies among females and an increased preference for fast food and meat among males. These results may be potentially important targets for interventions for stress-related food consumption.