The rising carbon dioxide (CO2) emissions over the decades is known to be a huge contributor to the greenhouse effect. CO2 capture and storage methods have been perceived as favourable solutions to prevent global warming and climate change rising from the greenhouse effect. One energy efficient technology for separating CO2 is the development of high-performing CO2 gas separating membranes. A variety of membrane-based gas separation technologies designed have shown promising results and are inexpensive. A high-performing membrane must have a defect-free, thin dense skin-layer with a porous sub-layer for support that permits great permeation rate and selectivity. Of all ranges of polymers used to make polymeric membranes for CO2/nitrogen (N2) separation, cellulose acetate (CA) polymer membranes are known for their high CO2 solubility. In this research, the effect of CA polymer concentrations at low acetyl group of 39.8% and casting thickness on the structure and morphologies of the membranes were studied. The CA polymer concentration was optimised from a range of 10 wt%, 15 wt% and 20 wt%, and the casting thickness was optimised from a range of 150 μm to 400 μm using wet-phase inversion technique. The results obtained exhibit a CA membrane with thin dense, selective skin-layer achieved at CA polymer concentration of 15 wt% and a casting thickness of 300 μm, with a CO2 permeance rate of 401.173 ± 0.579 (GPU), N2 permeance rate of 133.499 ± 0.148 (GPU) and selectivity of 3.009 ± 0.00656. This CA membrane is able to contribute to promising gas separation performances with enhanced physical and mechanical support by improvement of membrane permeance and selectivity towards CO2/N2 separation performance.
Although the use of contraceptive hormones is a risk factor for development of breast cancer, level of risk is unknown; thus the current research was conducted to investigate the effect of factors related to fertility and hormone use on risk of breast cancer in women aged under 50 years old in the west of Iran.
Introduction: Several lines of evidence suggest the contribution of cancer stem cells (CSCs) to the tumorigenicity of bladder cancer. Although CD133 and CD24 CSC biomarkers are associated with survival disadvantages in some cancers, the biological attributes of a specific tumor alters the expression of these markers and any associated phenotypic characteristics. Aim: To analyze CD133 and CD24 expression and their different phenotypes in urinary bladder carcinoma. Material and methods: Expression of CD133 and CD24 and their divergent phenotypes were analyzed in patients with urinary bladder carcinoma (n=60) and correlated with clinicopathological parameters. Results: CD133 + and CD24 + umor cells were more frequent in high grade, less differentiated carcinomas (18/22, and 15/17, p =0.022 and 0.01, respectively), muscle invasive tumors (20/22, p =0.017 and 17/17, p =0.001, respectively), and tumors with advanced stage ( p =0.001 and 0.007, respectively). The expression of CD24 slightly correlated with lymphovascular invasion ( p =0.04), whereas CD133 was associated with distant metastasis. The CD133 + CD24 + phenotype exhibited more aggressive tumorigenic behavior than other phenotypes. Conclusion: CD133 + and CD24 + cells correlated with determinants of aggressive behavior and may be involved in tumor progression and distant metastasis. The CD133 + subpopulation is likely to have a more potent tumorigenic capacity. Although divergent, the strong correlation between the two populations may support phenotypic plasticity among them. Compared to the CD133 + CD24 - and CD133 - CD24 + phenotypes, the CD133 + CD24 + phenotype is the most aggressive. These putative biomarkers can potentially aid in the selection of high-risk patients for more aggressive targeted therapy.
Worldwide, in the last decade, the numbers of new HIV infections and AIDS-related deaths have drastically decreased. Despite that, around 18 million infected individuals receive antiretroviral therapy and thus tend to live longer. This cross-sectional study was conducted to assess the level of HIV-related knowledge among undergraduate dental students at Ain Shams University (ASU) in Cairo, Egypt and to determine their attitudes toward treating HIV-positive patients.