1,733 research outputs found
Chemistry of South African Lamiaceae: Structures and Biological Activity of Terpenoids
South Africa flora is one of the most important mega floras with high endemic species percentage. Lamiaceae is an important family in South Africa with ±308 species in 41 genera and contains many important plants (~23%) traditionally used for treatment of different human diseases. The chemical profile of Lamiaceae is very rich in terpenoids in general and more specifically diterpenes. Genera like Leonotis and Plectranthus are well studied, while on the other hand, genus like Stachys (~41 species, ~50% endemic) didn’t receive any attention. Different classes of diterpenes were identified and some of them demonstrating important biological activities
Numerical assessment of the overall heat transfer and pressure drop performances of an aqueous ammonia base-nanofluids in rectangular microchannel heat sinks
In this paper, the thermal and hydrodynamic performances of an aqueous ammonia base-nanofluid (Al2O3-NH3(aqu)) cooled in a rectangular microchannel heat sink was numerically investigated. The range of Reynolds number used in the investigation were between 140-1400. In order to assess the performance of the system during the employment of the proposed nanofluid, H2O and Al2O3-H2O were also tested and their performances were compared to Al2O3-NH3(aqu) performance in terms of thermal resistance and pressure drop. Results from the simulation showed that the proposed nanofluid outperformed pure water and slightly higher than Al2O3-H2O in terms of thermal resistance (for Re = 1400, 0.0474, 0.0449 and 0.04647 oK/W for H2O, Al2O3-H2O and Al2O3-NH3(aqu), respectively). However, it exceeds the performance of both pure water and Al2O3-H2O in terms of pressure drop (for Re = 1400, 785288, 911217, 753591 Pa for H2O, Al2O3-H2O and Al2O3-NH3(aqu), respectively). The key findings from the current study may be used to attract more research about the proposed nanofluid to be used in the cooling process of microchannel heat sinks
Efecto sobre la oxidación de triglicéridos purificados del aceite de girasol, del extracto de acetona del fruto de Maclura pomifera, de la pomiferina y de la osajina
omiferin and osajin have been isolated from the acetonic extract of M. pomifera fruits. Effects of total acetonic extract, pomiferin and osajin on the autooxidation of purified sunflower triacylglycerol were studied. Pomiferin showed a high antioxidant activity whereas total acetonic extract showed moderate and osajin revealed a low activity.Se han aislado la pomiferina y la osajina del extracto de hexano del fruto de M. pomifera. Se han estudiado los efectos sobre la oxidación de triglicéridos purificados del aceite de girasol, del extracto de acetona, de la pomiferina y de la osajina. La pomiferina mostró una actividad antioxidante elevada en cambio, el extracto de acetona mostró una actividad moderada y la osajina baja
New cytotoxic cinnamic acid derivatives from leaves of Bonamia trichantha
Journal ArticleBioassay-guided fractionation of the methanolic extract of the young leaves of Bonamia trichantha led to the isolation of four new cinnamic acid derivatives trichanthins A-D (l-4).Their structures were established by spectroscopic methods. All compounds were tested in cytotoxic assays against the MCF-7, H-460 and SF-268 human cancer cell lines
Mejora de las soluciones del problema del viajante múltiple mediante técnicas de aprendizaje automático y optimización de Harris Hawks
This work introduces an approach to solving the Multiple Traveling Salesman Problem (mTSP) by integrating metaheuristic algorithms (MHs) with machine learning (ML) techniques. Specifically, the Discrete Harris Hawks Optimization (DHHO) algorithm was developed to handle the discrete nature of the mTSP, as the original Harris Hawks Optimization (HHO) was designed for continuous problems. The DHHO algorithm, enhanced with SARSA-based learning mechanisms for solution initialization and parameter tuning, significantly improves the efficiency of mTSP solutions. By leveraging ML's adaptability within the robust MH framework, this study offers a novel perspective on combinatorial optimization problems, surpassing the best-known solutions (BKS) in various mTSP instances. The results were tested using TSPLIB benchmark instances, including Att48, Berlin52, Bier127, Pr76, and Rat99, for two, three, and four salesmen, achieving optimal results in 12 out of 15 instances. The DHHO's performance was validated by the quality of solutions and consistency across multiple runs, with optimal results in 5 out of 5 instances for two salesmen, 3 out of 5 for three salesmen, and 4 out of 5 for four salesmen. Statistical validation using the Wilcoxon signed-rank test confirmed the significance of these improvements (p < 0.05). This work highlights the impact of integrating MHs and ML, making a substantial contribution to the current literature.Este trabajo presenta un enfoque para resolver el Problema del Viajante Múltiple (mTSP) mediante la integración de algoritmos metaheurísticos (MHs) con técnicas de aprendizaje automático (ML). En particular, se desarrolló el algoritmo de Optimización Discreta de Halcones de Harris (DHHO) para manejar la naturaleza discreta del mTSP, ya que el algoritmo original de Optimización de Halcones de Harris (HHO) fue diseñado para problemas continuos. El algoritmo DHHO, mejorado con mecanismos de aprendizaje basados en SARSA para la inicialización de soluciones y ajuste de parámetros, mejora significativamente la eficiencia de las soluciones del mTSP. Al aprovechar la adaptabilidad del ML dentro del robusto marco de MH, este estudio ofrece una nueva perspectiva sobre los problemas de optimización combinatoria, superando las mejores soluciones conocidas (BKS) en varias instancias del mTSP. Los resultados se probaron utilizando instancias de referencia de TSPLIB, incluyendo Att48, Berlin52, Bier127, Pr76 y Rat99, para dos, tres y cuatro vendedores, logrando resultados óptimos en 12 de las 15 instancias. El rendimiento del DHHO se validó por la calidad de las soluciones y la consistencia a lo largo de múltiples ejecuciones, obteniendo resultados óptimos en 5 de 5 instancias para dos vendedores, 3 de 5 para tres vendedores y 4 de 5 para cuatro vendedores. La validación estadística mediante la prueba de rango con signo de Wilcoxon confirmó la significancia de estas mejoras (p < 0.05). Este trabajo destaca el impacto de integrar MHs y ML, contribuyendo de manera sustancial a la literatura actual
Uterine sparing approaches in management of placenta accreta: a summarized review
Placenta accreta is a potentially life-threatening obstetric condition that required multidisciplinary approach to management. Placenta accreta occurs in complete absence of the decidua basalis. Women with previous cesarean section delivery or placenta previa are known to be at greater risk of placenta accreta. A previous study reported that 24%& 67% increase in the incidence of placenta accreta in women 1 versus 3 or more previous cesarean deliveries respectively. Antenatal diagnosis of placental invasion has the potential to improve maternal and fetal outcomes. In practice, incomplete non-separation of the placenta at delivery leads to massive obstetric hemorrhage resulting in maternal morbidities such as massive blood transfusion, DIC, injury to the bladder and intestines and the need for hysterectomy. Sonographic examination with gray scale and color doppler imaging is the recommended first line modality for diagnosis of morbidly adherent placenta. Techniques developed for conservative management are techniques developed to preserve uterus and future fertility which is crucially linked to societal status and self-esteem
THE ANTI-CATARACT EFFECT OF COENZYME Q10 IN RABBITS
Objective: cataract is the opacity of the lens which progressively impairs the light transmission to the retina and finally prevents the vision, these opacity result from the oxidative process in the eye. The study aimed to prevent opacity of the lens by using Coenzyme Q10 as eye drops.Methods: Sodium selenite 0.01w/v injected intravitreal to the rabbit's eye to induce the disease, a group of rabbits were receive Coenzyme Q10 eye drop, and another group received distilled water, pre and post induction, cataract maturity was measured to evaluate the opacity deterioration.Results: the group of rabbits that received distilled water after induction of cataract, the opacity occurred within 48-72 h and the mean score of opacity reached to (4±0.00), while Coenzyme Q10 treated group the degree of opacity was (1.5±0.02), and there was a highly significant difference (p<0.01).Conclusion: Coenzyme q10 has an antioxidant activity when use as eye drops and this effect enable Coenzyme Q10 to prevent the opacity which is the major cause of cataract due to oxidative stress
Problems of the fuel and energy complex of Iraq: Analysis and possible solutions
In this article, the authors analyze the state of the fuel and energy complex in Iraq. Authors try to make Iraq start a new path for development fuel and energy sector by reviewing investments in this sector. Iraqi Ministry of oil has announced ambitious plans to raise oil production and exports over the current decade by relying on foreign investment as a main means to achieve this increased production, and the main way for investors seeking to enter the Iraqi oil and gas market is growing by the oil licensing rounds announced by the Iraqi ministry of oil
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