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From the multitude of materials currently available on the market that can be used in the development of microparticles, sodium alginate has become one of the most studied natural anionic polymers that can be included in controlled-release pharmaceutical systems alongside other polymers due to its low cost, low toxicity, biocompatibility, biodegradability and gelatinous die-forming capacity in the presence of Ca2+ ions. In this review, we have shown that through coacervation, the particulate systems for the dispensing of drugs consisting of natural polymers are nontoxic, allowing the repeated administration of medicinal substances and the protection of better the medicinal substances from degradation, which can increase the capture capacity of the drug and extend its release from the pharmaceutical form.  相似文献   
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ABSTRACT

We combine satellite imagery, urban growth modelling, groundwater modelling and hydrogeological field expeditions to estimate the potential impacts in 2050 of rapid urbanization and climate change on groundwater in Arusha, Tanzania, and by extension similar areas in Sub-Saharan Africa. Our analysis suggests that a reduction of groundwater recharge by 30–44% will cause groundwater levels to drop by up to 75 m, mainly due to increased evapotranspiration and to an expansion in paved surface. If this scenario becomes reality, we predict that wells will run dry, creating health, social and environmental risks.  相似文献   
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Computer aided casting of aluminum using die-casting was developed. A piston, which is an automobile part and very important in internal combination engine, was chosen for the research. Pistons are made of aluminum alloy. Models of the products were developed to aid the casting process. Mathematical models that show the dimensions of the casting were also developed. Since the project is about using computer to aid casting process, a program using visual basic (VB) Language was developed. The program was used to incorporate die-casting process into computer system. The written program was tested and the model of the casting product (piston) was displayed. The result shows that computer which is faster with accurate result can be used as an aid in the production of aluminum piston using die-casting process, for accurate planning in the manufacture of the product.  相似文献   
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Zinc is an essential nutrient for human health. It plays key roles in maintaining protein structure and stability, serves as catalytic factor for many enzymes, and regulates diverse fundamental cellular processes. Zinc is important in affecting signal transduction and, in particular, in the development and integrity of the immune system, where it affects both innate and adaptive immune responses. The eye, especially the retina‐choroid complex, has an unusually high concentration of zinc compared to other tissues. The highest amount of zinc is concentrated in the retinal pigment epithelium (RPE) (RPE‐choroid, 292 ± 98.5 µg g?1 dry tissue), followed by the retina (123 ± 62.2 µg g?1 dry tissue). The interplay between zinc and inflammation has been explored in other parts of the body but, so far, has not been extensively researched in the eye. Several lines of evidence suggest that ocular zinc concentration decreases with age, especially in the context of age‐related disease. Thus, a hypothesis that retinal function could be modulated by zinc nutrition is proposed, and subsequently trialled clinically. In this review, the distribution and the potential role of zinc in the retina‐choroid complex is outlined, especially in relation to inflammation and immunity, and the clinical studies to date are summarized.  相似文献   
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The research focused on nanomaterial solutions and their flow characteristics in relation to their usage. The application of such composites in biological rheological models, in particular, has received a lot of interest. The use of nanofluids in cooling tiny electronic devices like microchips and associated devices cannot be emphasized. Our goal is to explore the influence of a binary chemical reaction and Arrhenius activation energy on a hybrid nanofluid over a melting wedge in a spongy media. It is anticipated that the water-based nanoparticle contains gyrotactic microbes. By using appropriate similarity variables, the resultant dimensional nonlinear boundary-layer model is reduced and turned into a dimensionless form. A Chebyshev spectral collocation approach is useful in solving the highly nonlinear model. In terms of physical importance, the effects of important factors on developing profiles are displayed graphically and explained. Computational outcomes are obtained via MATHEMATICA. The plot of residual error is also shown to demonstrate the method's rapid convergence. According to the study's findings, by increasing the melting parameter, the rate of heat transportation at the wall decreases greatly on the average of 12.81%, but the Sherwood number becomes effective for the chemical reaction rate with a rate of about 24.81%.  相似文献   
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This study was carried out to determine the chemical composition, antinutrient and phytonutrient contents of some wild fruits, namely African star apple (Chrysophyllum albidum G. Don.), hog plum (Spondias mombin Linn.), bush mango (Irvingiagabonensis Baill) and monkey cola (Colamillenii K. Schum). Samples of the wild fruit commonly consumed were collected from some villages in Ido Local Government Area, Oyo State Nigeria. The wild fruits were analysed for phytonutrients, antioxidants and mineral composition. Ranges of total phenolics and total anthocyanin content of these wild fruits were 27.78 ± 6.01 in I. gabonensis, 57.42 ± 4.47 in S. mombin, 121.29 ± 4.97 in C. millenii and 398.23 ± 0.00 in C. albidum respectively. Significant differences (p < 0.05) were found in antinutrient, phytonutrient and mineral composition of C. albidum, I. gabonensis and C. millenii. The analysis of variance revealed that calcium and manganese contents of I. gabonensis were significantly (p < 0.05) higher than those of C. albidum and C. millenii. The antioxidants especially vitamin C content ranged from as low as 15.87 mg/100 g in C. albidum to as high as 204.86 mg/100 g in S. mombin. The values for total carotenoid ranged from 172.77 μg/100 g (in C. millenii) to 1380.17 μg/100 g (in C. albidum). The wild fruits are sources of phytonutrients, antioxidants such as vitamin C, total carotenoids and some minerals. Planting of the wild fruit trees or the incorporation in farming systems should thus be encouraged to increase production and availability to consumers and as industrial raw materials.  相似文献   
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Kaduna     
Compared with other ancient towns like Kano, Ile-Ife or Oyo, Kaduna is relatively new in the hierarchy of towns in Nigeria. It has, however, the distinction of having being established in the large northern protectorate solely for colonial administrative purposes. Kaduna was originally built on a grid pattern, with all roads intersecting and properly named. Facilities were well planned and most town planning rules obeyed. But the pressure of urbanization, the existence of many development agencies whose activities are not coordinated and political interference in planning functions are threatening to deface the beauty of the city. The government is constantly evolving strategies to maintain and enhance the beauty of the town through various land management procedures.  相似文献   
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