581 research outputs found

    Antibacterial and Cytotoxic Activities of Capparis zeylanica Linn Roots

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    Se analizaron extractos crudos y un ácido graso, ácido octadec-7-en-5-ynoic (1), de la corteza de la raíz de Capparis zeylanica Linn. (familia de las Capparidaceae) para observar sus actividades antibacterianas frente a la bacteria Gram positiva y Gram negativa. Entre los extractos crudos, el extracto de cloroformo mostró una buena actividad frente a todos los organismos de prueba. El ácido graso (1) aislado del extracto de cloroformo mostró actividades antibacterianas frente a todos los organismos de prueba, a excepción de E. coli. Las actividades se compararon con un antibiótico estándar: la kanamicina. Las concentraciones inhibitorias mínimas (CIH) de 1, determinadas mediante la técnica de dilución en serie, fueron 64 μg/ml frente a Bacillus subtilis y Shigella dysenteriae. Las actividades citotóxicas del extracto crudo y del ácido graso (1) se observaron mediante el bioensayo de gambas en salmuera y el valor de LC50 del compuesto fue 6,27 μg/mlCrude extracts and a fatty acid, octadec-7-en-5-ynoic acid (1), from the root bark of Capparis zeylanica Linn. (Fam. Capparidaceae) were screened for their antibacterial activities against Gram positive and Gram negative bacteria. Among the crude extracts, chloroform extract showed good activity against all test organisms. The fatty acid (1) isolated from chloroform extract exhibited antibacterial activities against test organisms except E. coli. The activities were compared to a standard antibiotic- kanamycin. The minimum inhibitory concentrations (MICs) of 1, determined by serial dilution technique, were found to be 64 μg/ml against Bacillus subtilis and Shigella dysenteriae. The cytotoxic activities of crude extract and fatty acid (1) were observed by brine shrimp biassay and LC50 value of the compound was found to be 6.27 μg/m

    Chemical ultraviolet absorbers topically applied in a skin barrier mimetic formulation remain in the outer stratum corneum of porcine skin

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    The objective of the present study was to evaluate the fate of three chemical sunscreens, isoamyl p-methoxycinnamate (IPMC), diethylamino hydroxybenzoyl hexyl benzoate (DHHB), and bis-ethylhexylphenol methoxyphenyl triazine (BEMT), topically applied to mammalian skin from a skin barrier mimetic oil-in-water formulation. High Performance Liquid Chromatography (HPLC) methods were developed for the analysis of each molecule and validated. Franz cell permeation studies were conducted following application of finite doses of the formulations to excised porcine skin. A vehicle formulation containing no sunscreens was evaluated as a control. Permeation studies were conducted for 12 h after which full mass balance studies were carried out. Analysis of individual UV sunscreens was achieved with HPLC following application of the formulation to the skin with no interference from the vehicle components. No skin permeation of any of the chemical sunscreens was evident after 12 h. While sunscreens were detected in up to 12 tape strips taken from the SC, 87% or more of the applied doses recovered in the first 5 tape strips. When corrected for the amount of protein removed per tape strip this corresponded to a penetration depth in porcine stratum corneum of ∼1.7 μm. Mass balance studies indicated total recovery values were within accepted guidelines for cosmetic formulations. Overall, only superficial penetration into the SC was observed for each compound. These findings are consistent with the physicochemical properties of the selected UV absorbing molecules and their formulation into an ordered biomimetic barrier formulation thus support their intended use in topical consumer formulations designed to protect from UV exposure. To our knowledge this is the first report of depth profiling of chemical sunscreens in the SC that combines tape stripping and protein determination following in vitro Franz cell studies

    A Survey of Scheduling in 5G URLLC and Outlook for Emerging 6G Systems

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    Future wireless communication is expected to be a paradigm shift from three basic service requirements of 5th Generation (5G) including enhanced Mobile Broadband (eMBB), Ultra Reliable and Low Latency communication (URLLC) and the massive Machine Type Communication (mMTC). Integration of the three heterogeneous services into a single system is a challenging task. The integration includes several design issues including scheduling network resources with various services. Specially, scheduling the URLLC packets with eMBB and mMTC packets need more attention as it is a promising service of 5G and beyond systems. It needs to meet stringent Quality of Service (QoS) requirements and is used in time-critical applications. Thus through understanding of packet scheduling issues in existing system and potential future challenges is necessary. This paper surveys the potential works that addresses the packet scheduling algorithms for 5G and beyond systems in recent years. It provides state of the art review covering three main perspectives such as decentralised, centralised and joint scheduling techniques. The conventional decentralised algorithms are discussed first followed by the centralised algorithms with specific focus on single and multi-connected network perspective. Joint scheduling algorithms are also discussed in details. In order to provide an in-depth understanding of the key scheduling approaches, the performances of some prominent scheduling algorithms are evaluated and analysed. This paper also provides an insight into the potential challenges and future research directions from the scheduling perspective

    Effect of acrylic acid on the properties of polyvinylpyrrolidone hydrogel prepared by the application of gamma radiation

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    Hydrogels based on polyvinylpyrrolidone (PVP) networks grafted with acrylic acid (AAc) was prepared by using γ-rays from a Co-60 source at room temperature. The parameters like effect of radiation dose and concentration of AAc were studied. The properties such as gel content, swelling behavior and thermal stability were also evaluated. The result indicated that gel content of hydrogel increased with increased radiation dose and it reached a maximum value at 25 kGy radiation dose. Gel content also increased with increased concentration of AAc in the feed solution. Moreover, swelling ratio decreased with increased radiation dose, but increased with increased concentration of AAc. Water absorption of hydrogel increased from ~1400 to ~3800% for the range of AAc concentration 0 to 1.5% at 25 kGy. It was also observed that the melting temperature of hydrogel depended on concentration of AAc. The fourier transform infra-red (FTIR) spectroscopy investigation of hydrogel was carried out. The prepared hydrogel was applied to adsorb dye from aqueous medium.Keywords: Hydrogel, polyvinylpyrrolidone, acrylic acid, swelling behavior, gel conten

    COMPARISON OF THE EFFECTS OF GROWTH REGULATORS ON IN VITRO REGENERATION OF RIDGE GOURD AND SPONGE GOURD THROUGH SHOOT

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    Abstract Context: Luffa cylindrica and Luffa acutangula are highly cross pollinated crops and propagated mainly by seeds. Genetic stability cannot be maintained easily by seed propagation. It can be maintain by developing special vegetative technique through tissue culture. Objectives: To compare the effects of growth regulators between two species of Luffa using shoot tips for develop the rapid, simple and efficient in vitro regeneration protocol. Materials and Methods: Shoot tips used were collected from in vivo grown plants. They were excised from plants and surface sterilized by HgCl2 treatment. The isolated tips were cultured on semisolid MS medium supplemented with different concentrations and combinations of different growth regulators. Results: The highest result of direct shoot multiplication of ridge gourd was observed using 2 mg/l BAP + 0.2 mg/l GA and in case of sponge gourd it was 1.5 mg/l BAP. For callus induction significant result was found using 4 mg/l BAP + 0.2 mg/l NAA in ridge gourd and 3 mg/l BAP + 0.2 mg/l NAA in sponge gourd. Indirect regeneration was performed by subculturing organogenic callus of sponge gourd on MS with 1.5 mg/l BAP + 0.2 mg/l GA3 and the callus of ridged gourd on MS + 1.5 mg/l BAP + 0.2 mg/l NAA + 0.2 mg/l nicotinic acid. Regenerated shoots of both species were rooted well on MS containing NAA at low concentration. Conclusion: Hormonal differences and simple rapid in vitro regeneration protocol of L. cylindrica and L. acutangula have been established

    In vitro permeation and disposition of niacinamide in silicone and porcine skin of skin barrier-mimetic formulations.

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    Niacinamide (NIA) is an amide form of vitamin B3 which is used in cosmetic formulations to improve various skin conditions and it has also been shown to increase stratum corneum thickness following repeated application. In this study, three doses (5, 20 and 50μl per cm(2)) of two NIA containing oil-in-water skin barrier-mimetic formulations were evaluated in silicone membrane and porcine ear skin and compared with a commercial control formulation. Permeation studies were conducted over 24h in Franz cells and at the end of the experiment membranes were washed and niacinamide was extracted. For the three doses, retention or deposition of NIA was generally higher in porcine skin compared with silicone membrane, consistent with the hydrophilic nature of the active. Despite the control containing a higher amount of active, comparable amounts of NIA were deposited in skin for all formulations for all doses; total skin absorption values (permeation and retention) of NIA were also comparable across all formulations. For infinite (50μL) and finite (5μL) doses the absolute permeation of NIA from the control formulation was significantly higher in porcine skin compared with both test formulations. This likely reflects differences in formulation components and/or presence of skin penetration enhancers in the formulations. Higher permeation for the 50 and 20μl dose was also evident in porcine skin compared with silicone membrane but the opposite is the case for the finite dose. The findings point to the critical importance of dose and occlusion when evaluating topical formulations in vitro and also the likelihood of exaggerated effects of excipients on permeation at infinite and pseudo-finite dose applications

    Optimization of Tremblay's battery model parameters for plug-in hybrid electric vehicle application

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    Accurate modeling of batteries for plug-in hybrid vehicle applications is of fundamental importance to optimize the operation strategy, extend battery life and improve vehicle performance. Tremblay’s battery model has been specificallydesigned and validated for electric vehicle applications. Tremblay’s parameter identification method is based on evaluating the three remarkable points manually picked from a manufacturer’s discharge curve. This method is error prone and the resultant discharge curve may deviate significantly from the experimental curve as reported in previous studies. This paper proposes to use a novel quantum-behaved particle swarm optimization (QPSO) parameter estimation technique to estimate the model parameters. The performance of QPSO is compared to that of genetic algorithm (GA) and particle swarm optimization (PSO) approaches. The QPSO technique needs less tuning effort than other techniques since it only uses one tuning parameter. Reducing the number of iterations should be a welcome development in most applications areas. Results show that the QPSO parameter estimation technique converges to acceptable solutions with fewer iterations than that obtained by the GA and the PSO approaches

    Interactions between selected bile salts and Triton X-100 or sodium lauryl ether sulfate

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    <p>Abstract</p> <p>Background</p> <p>In order to develop colloidal drug carriers with desired properties, it is important to determine physico-chemical characteristics of these systems. Bile salt mixed micelles are extensively studied as novel drug delivery systems. The objective of the present investigation is to develop and characterize mixed micelles of nonionic (Triton X-100) or anionic (sodium lauryl ether sulfate) surfactant having oxyethylene groups in the polar head and following bile salts: cholate, deoxycholate and 7-oxodeoxycholate.</p> <p>Results</p> <p>The micellization behaviour of binary anionic-nonionic and anionic-anionic surfactant mixtures was investigated by conductivity and surface tension measurements. The results of the study have been analyzed using Clint's, Rubingh's, and Motomura's theories for mixed binary systems. The negative values of the interaction parameter indicate synergism between micelle building units. It was noticed that Triton X-100 and sodium lauryl ether sulfate generate the weakest synergistic interactions with sodium deoxycholate, while 7-oxodeoxycholate creates the strongest attractive interaction with investigated co-surfactants.</p> <p>Conclusion</p> <p>It was concluded that increased synergistic interactions can be attributed to the larger number of hydrophilic groups at α side of the bile salts. Additionally, 7-oxo group of 7-oxodeoxycholate enhance attractive interactions with selected co-surfactants more than 7-hydroxyl group of sodium cholate.</p

    Modelling malaria treatment practices in Bangladesh using spatial statistics

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    <p>Abstract</p> <p>Background</p> <p>Malaria treatment-seeking practices vary worldwide and Bangladesh is no exception. Individuals from 88 villages in Rajasthali were asked about their treatment-seeking practices. A portion of these households preferred malaria treatment from the National Control Programme, but still a large number of households continued to use drug vendors and approximately one fourth of the individuals surveyed relied exclusively on non-control programme treatments. The risks of low-control programme usage include incomplete malaria treatment, possible misuse of anti-malarial drugs, and an increased potential for drug resistance.</p> <p>Methods</p> <p>The spatial patterns of treatment-seeking practices were first examined using hot-spot analysis (Local Getis-Ord Gi statistic) and then modelled using regression. Ordinary least squares (OLS) regression identified key factors explaining more than 80% of the variation in control programme and vendor treatment preferences. Geographically weighted regression (GWR) was then used to assess where each factor was a strong predictor of treatment-seeking preferences.</p> <p>Results</p> <p>Several factors including tribal affiliation, housing materials, household densities, education levels, and proximity to the regional urban centre, were found to be effective predictors of malaria treatment-seeking preferences. The predictive strength of each of these factors, however, varied across the study area. While education, for example, was a strong predictor in some villages, it was less important for predicting treatment-seeking outcomes in other villages.</p> <p>Conclusion</p> <p>Understanding where each factor is a strong predictor of treatment-seeking outcomes may help in planning targeted interventions aimed at increasing control programme usage. Suggested strategies include providing additional training for the Building Resources across Communities (BRAC) health workers, implementing educational programmes, and addressing economic factors.</p

    Multivariable control of a grid-connected wind energy conversion system with power quality enhancement

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    This document is the Accepted Manuscript version of the following article: Kaddour Fouad, Houari Merabet Boulouiha, Ahmed Allali, Ali Taibi, and Mouloud Denai, ‘Multivariable control of a grid-connected wind energy conversion system with power quality enhancement’, Energy Systems, Vol. 9 (1): 25-57, February 2018. The final publication is available at Springer via: https://doi.org/10.1007/s12667-016-0223-7This paper proposes the design of a multivariable robust control strategy for a variable-speed WECS based on a SCIG. Optimal speed control of the SCIG is achieved by a conventional PI controller combined with a MPPT strategy. DTC-SVM technique based on a simple Clarke transformation is used to control the generator-side three-level converter in the variable speed WECS. The flow of real and reactive power between the inverter and the grid is controlled via the grid real and reactive currents and the DC link voltage using multivariable H∞ control. The overall WECS and control scheme are developed in Matlab/Simulink and the performance of the proposed control strategy is evaluated via a set of simulation scenarios replicating various operating conditions of the WECS such as variable wind speed and asymmetric single grid faults. The power quality of the WECS system under H∞ control control approach is assessed and the results show a significant improvement in the total harmonic distorsion as compared to that achieved with a classical PI control.Peer reviewedFinal Accepted Versio
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