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One-dimensional optical waveguide calculations were performed to study the dependence of waveguide design on confinement factor (Γ) and optical losses (αi) of nitride laser diodes for emission wavelength ranging from 405 nm to 520 nm. We found that the conventional waveguide design containing GaN waveguide and AlGaN cladding layers known from violet laser diode does not support sufficient confinement of the optical mode for long wavelength devices (λ > 450 nm). We proposed a new design consisting of a thick InGaN waveguide which enhances the confinement. We compared the theoretical predictions with laser diodes grown by plasma assisted molecular beam epitaxy. [ABSTRACT FROM AUTHOR]

AIM OF THE STUDY: The preventive effect of the hydro-alcoholic extracts of Artemisia herba-alba Asso (AHA), and Centaurium erythraea Rafn (CE), two medicinal plants used in traditional treatment of diabetes in the north-eastern Algeria, were evaluated in animal models of type 2 diabetic induced with a standardised high fat diet (HFD). MATERIALS AND METHODS: Plant extracts were administered orally by gavage at a dose of 2 g/kg bodyweight daily for 20 weeks to male C57BL/6J mice fed HFD. Animals were weighed and plasma glucose measured weekly and insulin at the end of study using standard ELISA methods. RESULTS: After 6 weeks, blood glucose levels increased in HFD control mice. At end of study (20 weeks) in groups treated with AHA or CE extracts vs. HFD control group there was a significant reduction in mean (+/-SD) fasting blood glucose (respectively 108.0+/-42.0 and 120.4+/-45.1 vs. 183.1+/-19.1 mg/dl, p<0.05), triglyceride concentrations (26.9+/-6.7 and 27.9+/-17.8 vs. 48.9+/-12.1 mg/dl, p<0.05) and serum insulin levels (1.1+/-1.0 and 0.6+/-0.7 vs. 3.1+/-1.8 ng/ml, p<0.05). Plant extracts also markedly reduced insulin resistance as measured by the homeostasis model assessment (HOMA) compared to HFD controls (AHA: 4.4+/-5.3, CE: 3.0+/-3.3 vs. HFD control 38.3+/-26.6, p<0.05). The plant extracts had no effect on calorie intake or body weight. CONCLUSION: AHA had been shown to have a hypoglycaemic effect in diabetes but this is the first demonstration of a preventive effect of AHA and CE on HFD-induced diabetes. [ABSTRACT FROM AUTHOR]

Ethnopharmacological Relevance: Plants are traditionally used in Algeria to treat many disorders, including diabetes mellitus. Knowledge of the plants that are used may provide insight on their properties, for further exploration. This study reviewed all the available published and unpublished reports concerning the use of herbal medicines in the treatment of diabetes in Algeria., Aim of the Study: To describe the plants used in Algeria to treat diabetes, as reported in the literature., Material and Methods: Systematic review of ethnobotanical papers published in the medical literature, from literature databases (Pubmed, Web of Science), as well as Google, for English, French and Arabic -language publication, and a manual search of local libraries and bookshops, as well as the university repository of PhD and master's theses. The reference lists of the papers retrieved were also examined for further papers., Results: Many plants are cited in the ethnobotanical surveys, but only very few pharmacological studies were found. In the ethnobotanical surveys, 171 plants were reported, from 58 families of which the most often cited were Asteraceae, Lamiaceae and Apiaceae. The plants with the best evidence of use and activity are: Anabasis articulata (Forssk.) Moq., Trigonella foenum-graecum L., Centaurium erythraea Rafn, Artemisia herba-alba Asso, Marrubium vulgare L., Agathophora alopecuroides (Delile) Fenzl ex Bunge, Anabasis articulata (Forssk.) Moq., Hammada elegans (Bunge) Botsch., Helianthemum kahiricum Delile, Salsola baryosma (Schult.) Dandy, Salsola vermiculata L., Olea europaea L., Conclusion: Traditional herbal medicines are still very much used in Algeria to control diabetes. However they are generally poorly characterized and none have been properly tested in man. There is a need for systematic evaluation of the more commonly used plants to confirm their antidiabetic activity, identify possible mechanimss of action, and recommend best use., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Ethnopharmacological Relevance: Centaurium erythraea Rafn (CE), Artemisia herba-alba Asso (AHA) and Trigonella foenum-graecum L. (TFG) are traditionally used to treat type 2 diabetes in Algeria, previous studies have found that extracts of these plants were effective to treat or prevent experimental diabetes induced by high-fat diet (HFD)., Aim of the Study: Describe the additional effects of these extracts on lipid tissue deposition in HFD., Materials and Methods: Male C57BL/6J mice were fed with HFD to induce type 2 Diabetes. Groups of mice were given plant extracts orally at 2g/kg/bodyweight daily for 20 weeks during establishment of diabetes, or for 18 weeks after confirmation of diabetes at the 17th week. Liver and other tissue samples were stained with Oil Red O., Results: Liver steatosis was confirmed with HFD. CE, AHA and TFG extracts improved liver steatosis by the end of the preventive (20 weeks) and curative periods (35 weeks). This was most marked for CE extract (p<0.05), less so with TFG and AHA. No steatosis was found in other tissues., Conclusion: CE extract had a clear hepatoprotective effect in this mouse model of diet-induced type 2 diabetes. AHA and TFG had a minimal or no significant effect on steatosis. Beyond its effect as an antidiabetic agent, CE may also be promising to prevent or treat non-alcoholic liver steatosis., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Ethnopharmacological Relevance: Trigonella foenum-graecum L. (TFG) is traditionally used to treat diabetes in North Africa. we therefore tested the effects of the hydro-alcoholic extract of TFG seeds in a C57/BL6J mouse model of diabetes induced by a standardised high-fat diet (HFD)., Materials and Methods: Plant extracts (2 g/kg daily) were administered orally by gavage at the start of HFD, or after confirmation of established diabetes (17th week), for 20 or 18 weeks, respectively, to male C57BL/6J mice. Animals were weighed; food intake and plasma glucose, lipid profile, insulin and insulin resistance were measured., Results: TFG extracts opposed the development of diabetes: compared with untreated HFD mice, TFG-treated HFD mice had lower mean (± SD) plasma glucose (129.3 ± 39.4 vs. 183.1 ± 19.1mg/dL, p<0.05), plasma insulin (1.3 ± 0.8 vs. 3.1 ± 1.8 ng/mL, p<0.05) and triglycerides (18.9 ± 12.9 vs. 48.9 ± 12.1mg/dL, p<0.05), and less insulin resistance as estimated by the homeostasis model assessment (HOMA: 9.7 ± 11.1 vs. 38.3 ± 26.6, p<0.05). In mice with established diabetes, TFG reduced fasting plasma glucose (170.4 ± 24.1 vs. 229.0 ± 20.8 mg/dL, p<0.05), plasma insulin (1.7 ± 1.3 vs. 3.3 ± 14.3 ng/mL, p<0.05) and insulin resistance (HOMA: TFG: 19.2 ± 15.7 vs. HFD control: 38.5 ± 30.3, p<0.05). In addition, administration of TFG extract also caused significant reduction in triglycerides (17.9 ± 9.7 vs. 62.8 ± 18.3 mg/dL, p<0.05) and total cholesterol (1.30 ± 0.20 vs. 1.80 ± 1.10 g/L, p<0.05), and an increase in HDL-cholesterol (1.6 ± 0.2 vs. 1.2 ± 0.1 g/L). The plant extract had no effect on calorie intake or body weight., Conclusion: TFG extract opposed the development of experimental HFD diabetes in mice, and had an anti-diabetic effect in mice with established diabetes., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Aim of the Study: Hydro-alcoholic extracts of Centaurium erythraea Rafn (CE), Gentianaceae and Artemisia herba-alba Asso (AHA), Asteraceae, medicinal plants used in traditional treatment of diabetes in north-eastern Algeria, were tested in established type 2 diabetes induced with a standardized high fat diet (HFD) in mice., Materials and Methods: After confirmation of diabetes (17th week), plant extracts were administered orally by gavage at a dose of 2 g/kg daily for 18 weeks to male C57BL/6J mice fed HFD. Animals were weighed, food intake and plasma glucose measured weekly, insulin and lipid profile at study end., Results: At 35 weeks, groups treated with AHA or CE vs. HFD control had a significant reduction in mean (±SD) fasting blood glucose concentrations (143.8±23.9 and 139.5±14.2 vs. 229.0±20.8 mg/dL, p<0.05, respectively), triglyceride (18.9±11.1 and 16.0±6.5 vs. 62.8±18.3 mg/dL, p<0.05), total cholesterol (1.2±0.1 and 1.2±0.3 vs. 1.8±1.1 g/L, p<0.05) and serum insulin concentrations (1.7±0.7 and 0.9±0.7 vs. 3.3±14.3 ng/mL, p<0.05). Plant extracts also markedly reduced insulin resistance as compared to HFD controls (AHA: 15.6±9.1, CE: 9.0±7.7 vs. HFD control 38.5±30.3, p<0.05). The plant extracts decreased calorie intake and had little effect on body weight or HDL-cholesterol., Conclusion: AHA has already been shown to have a antihyperglycaemic and antihyperlipidemic effect but this is the first demonstration of an effect of AHA and CE on established HFD-induced diabetes., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)