740 research outputs found

    Synthesis and Characterization of Vanadium Substituted Potassium Tungsten Bronzes, K x V y W 1-y O 3

    Get PDF
    A series of vanadium substituted potassium hexagonal tungsten bronzes KxVyW1-yO3 (K-HTB) were prepared by conventional solid state method at 800 °C with compositions of x = 0.30 and 0.00 ? y ? 0.15. A mixture of K-HTB and non bronze phases with y ? 0.20 was observed. The proportion of this non bronze phase increases with increasing vanadium content. The non bronze phases in the mixture could not be indexed yet. In contrast, a very small amount of vanadium can be substituted in potassium tetragonal tungsten bronzes (K-TTB) at 800 °C with x = 0.50 and 0.00 ? y ? 0.02, however at 700 °C vanadium substituted K-TTB can be prepared with 0.00 ? y ? 0.05. Further substitution of vanadium in K-TTB decomposes to K-HTB and non-bronze phases

    A Strategic Approach Using Representative LV Networks in the Assessment of Technical Losses on LV Network with Solar Photovoltaic

    Get PDF
    Low voltage network (LVN) forms an extensive part of the distribution network as it is used to connect electricity supply from utility substations to diverse segments of loads in different geographic locations. With the increasingly high penetration of solar PV in LVN, utility companies are finding it necessary to establish the contribution of these solar PV to the overall technical losses in the distribution network. This paper presents a strategic approach using representative LVN to determine the impact of solar PV on technical losses on the LVN. Five types of representative LVN characterized by different customer load segments (domestic, commercial and industrial) and peak load demand were developed. The impact on technical losses of solar PV connected to these representatives LVN were assessed on a statistical basis for a supply zone. The results obtained are consistent and could be applied to establish investment strategies on distribution network, tariff revision exercise and optimization of distribution network planning/design

    Cost efficiency of Yemen Islamic banks: An inefficiency effects approach (2002-2014)

    Get PDF
    REFERENCES   Battese, G. E. and T. J. Coelli. 1988. Prediction of firm-level technical efficiencies with a generalized frontier production function and panel data. Journal of Econometrics 38(3):387-399. Battese, G. E. and T. J. Coelli. 1992. Frontier production functions, technical efficiency and panel data: with application to paddy farmers in India. Journal of Productivity Analysis 3(1-2):153-169. Battese, G. E. and T. J. Coelli. 1995. A model for technical inefficiency effects in a stochastic frontier production function for panel data. Empirical Economics 20(2):325-332. Bushara, M. and M. Abuagla. 2016. Measuring production efficiency of sorghum small farmers in Rahad Agricultural Scheme season (2011-2012). Journal of Socialomics 5(192):1-10. Bushara, M. O. and M. G. Mohayidin. 2008. Cost efficiency of Malaysian oil and fat industry: An empirical evidence. Sudan Journal of  Agricultural Research 9:135-147. Hasan, M. and J. Dridi. 2011. The effects of the global crisis on Islamic and conventional banks: A comparative study. Journal of International Commerce, Economics and Policy 2(2):163-200. Huang, C. J. and J.-T. Liu. 1994. Estimation of a non-neutral stochastic frontier production function. Journal of Productivity Analysis 5(2):171-180. Isik, I. and M. K. Hassan. 2003. Financial deregulation and total factor productivity change: An empirical study of Turkish commercial banks. Journal of Banking and Finance 27(8):1455-1485. Kumbhakar, S. C., S. A. Ghosh and J. T. McGuckin. 1991. A generalized production frontier approach for estimating determinants of inefficiency in US dairy farms. Journal of Business and Economic Statistics 9(3):279-286. Kyj, L. and I. Isik. 2008. Bank x-efficiency in Ukraine: An analysis of service characteristics and ownership. Journal of Economics and Business 60(4):369-393. McKinnon, R. 1997. Money and capital in economic development. The Brookings Washington DC. Pasiouras, F. 2008. Estimating the technical and scale efficiency of Greek commercial banks: The impact of credit risk, off-balance sheet activities, and international operations. Research in International Business and Finance 22(3):301-318. Pitt, M. M., and L.F. Lee. 1981. The measurement and sources of technical inefficiency in the Indonesian weaving industry. Journal of Development Economics 9(1):43-64. Reifschneider, D. and R. Stevenson. 1991. Systematic departures from the frontier: A framework for the analysis of firm inefficiency. International Economic Review32(3):715-723. Samad, A. and M. K. Hassan. 1999. The performance of Malaysian Islamic bank during 1984-1997: An exploratory study. International Journal of Islamic Financial Services 1(3):1-14. Schmidt, P. and C. K. Lovell. 1979. Estimating technical and allocative inefficiency relative to stochastic production and cost frontiers. Journal of Econometrics 9(3):343-366. Sealey, C. W. and J. T. Lindley. 1977. Inputs, outputs and a theory of production and cost at depository financial institutions. The Journal of Finance 32(4):1251-1266. Sufian, F. and M. Akbar Noor Mohamad Noor. 2009. The determinants of Islamic banks' efficiency changes: Empirical evidence from the MENA and Asian banking sectors. International Journal of Islamic and Middle Eastern Finance and Management 2(2):120-138. Sufian, F. and M. S. Habibullah. 2010. Assessing the impact of financial crisis on bank performance: Empirical evidence from Indonesia. ASEAN Economic Bulletin27(3):245-262. Tecles, P. L. and B. M. Tabak. 2010. Determinants of bank efficiency: The case of Brazil. European Journal of Operational Research 207(3):1587-1598. Weill, L. 2004. Measuring cost efficiency in European banking: A comparison of frontier techniques. Journal of Productivity Analysis 21(2):133-152. Willison, B. 2009. Technology trends in Islamic investment banking. Islamic Finance News 6(19):22-23

    Nanoparticle dynamics in the presence and absence of a cellular uptake altering chemical

    Get PDF
    The far-reaching applications of nanoparticles (NPs) in drug delivery, medical imaging, diagnostics, and therapeutics have led to an increased potential for interfacing with a diverse range of biological environments. While metallic NPs such as copper NPs have been explored for their antimicrobial and catalytic properties, they have been shown to induce undesirable toxic effects. Nonetheless, biomodulators may be employed to control this cytotoxicity. Dynasore is a dynamin GTPase inhibitor that has been shown to rapidly and reversibly block clathrindependent endocytic traffic within minutes of application. Here, we demonstrate that Dynasore can chemically bio-modulate the toxic effects of copper nanoparticles (Cu NPs), but not through reducing Cu NP internalization. In fact, Dynasore seems to possess secondary effects that have been unreported to date. We propose and test three potential mechanisms of cytotoxicity modulation: 1) through changes in agglomeration pattern, 2) through potential quenching of reactive oxygen species (ROS), and 3) through Cu+2 ion chelation. These results have far-reaching implications for understanding the complex interactions that occur at the interface of NPs in biological environments, especially during mechanistic chemical modification strategies

    Computable Delay Margins for Adaptive Systems with State Variables Accessible

    Get PDF
    Robust adaptive control of plants whose state variables are accessible in the presence of an input time delay is established in this paper. It is shown that a standard model reference adaptive controller modified with projection ensures global boundedness of the overall adaptive system for a range of nonzero delays. The upper bound of such delays, that is, the delay margin, is explicitly defined and can be computed a priori. © 1963-2012 IEEE

    High performance methylated DNA markers for detection of colon adenocarcinoma

    Get PDF
    BACKGROUND: Colon cancer (CC) is treatable if detected in its early stages. Improved CC detection assays that are highly sensitive, specific, and available at point of care are needed. In this study, we systematically selected and tested methylated markers that demonstrate high sensitivity and specificity for detection of CC in tissue and circulating cell-free DNA. METHODS: Hierarchical analysis of 22 candidate CpG loci was conducted using The Cancer Genome Atlas (TCGA) COAD 450K HumanMethylation database. Methylation of 13 loci was analyzed using quantitative multiplex methylation-specific PCR (QM-MSP) in a training set of fresh frozen colon tissues (N = 53). Hypermethylated markers were identified that were highest in cancer and lowest in normal colon tissue using the 75th percentile in Mann–Whitney analyses and the receiver operating characteristic (ROC) statistic. The cumulative methylation status of the marker panel was assayed in an independent test set of fresh frozen colon tissues (N = 52) using conditions defined and locked in the training set. A minimal marker panel of 6 genes was defined based on ROC area under the curve (AUC). Plasma samples (N = 20 colorectal cancers, stage IV and N = 20 normal) were tested by cMethDNA assay to evaluate marker performance in liquid biopsy. RESULTS: In the test set of samples, compared to normal tissue, a 6-gene panel showed 100% sensitivity and 90% specificity for detection of CC, and an AUC of 1.00 (95% CI 1.00, 1.00). In stage IV colorectal cancer plasma versus normal, an 8-gene panel showed 95% sensitivity, 100% specificity, and an AUC of 0.996 (95% CI 0.986, 1.00) while a 5-gene subset showed 100% sensitivity, 100% specificity, and an AUC of 1.00 (95% CI 1.00, 1.00), highly concordant with our observations in tissue. CONCLUSIONS: We identified high performance methylated DNA marker panels for detection of CC. This knowledge has set the stage for development and implementation of novel, automated, self-contained CC detection assays in tissue and blood which can expeditiously and accurately detect colon cancer in both developed and underdeveloped regions of the world, enabling optimal use of limited resources in low- and middle-income countries. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13148-021-01206-2

    Screening of suitable ionic liquids as green solvents for extraction of eicosapentaenoic acid (EPA) from microalgae biomass using COSMO-RS model

    Get PDF
    Omega-3 poly unsaturated fatty acids (PUFA) particularly eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), have many health benefits including reducing the risk of cancer and cardiovascular disease. Recently, the use of ionic liquids (ILs) in lipid extraction from microalgae provides the potential to overcome common drawbacks, offers several other benefits. To date, very limited researches are available to focus on extracting microalgae lipid and PUFA in particular by using ILs. The objective of current work is to screen the potential ILs that can be applied in EPA extraction. In this study, fast ILs screening was performed with the help of a conductor like screening model for real solvents (COSMO-RS) and the ILs with higher capacity values for use in extraction of EPA were compared. According to the results, the highest capacity for EPA extraction among 352 screened cation/anion combinations belongs to [TMAm][SO4]. It is expected to achieve a higher yield of EPA once applying this combination as the solvent in the process of extraction. ILs with small anions were observed to have higher capacities, as well possessing higher charge density compared to larger ones, and therefore, they are more preferable for extraction purposes. Moreover, shorter alkyl chain cations are preferred when using imidazolium-based IL, which agrees with experimental data

    Favorable Changes in Fasting Glucose in a 6-month Self-Monitored Lifestyle Modification Programme Inversely Affects Spexin Levels in Females with Prediabetes

    Get PDF
    Spexin (SPX) is a novel peptide thought to have a role in various metabolic regulations. Given its presumed body-weight regulatory functions, we aimed to determine whether lifestyle intervention programs on weight loss and fasting glucose (FG) improvement among people with impaired glucose regulation also alter levels of circulating SPX. A total of 160 Saudi adult males and females with prediabetes were randomly selected from a larger cohort (N = 294) who underwent a 6-month lifestyle modification program to improve their glycemic status. Participants were split into two groups based on differences in glucose levels post-intervention, with the first 50% (improved group) having the most significant reduction in FG. SPX was measured at baseline and after 6 months. Changes in SPX was significant only in the improved group [baseline: median (Q1\u2013Q3) of 164 pg/ml (136\u2013227) vs follow-up: 176 pg/ml (146\u2013285); p < 0.01]. When stratified by sex, the significant increase was observed only in females [159 pg/ml (127\u2013252) vs 182.5 (152,369.1); p < 0.01]. Furthermore, SPX levels showed a significant inverse association with FG (\u3b2 = 120.22, p = 0.003) even after adjustment with age and BMI, again only in females. Circulating SPX levels increase over time in people with prediabetes, particularly women who responded favorably in a 6-month lifestyle intervention program. Whether an unknown mechanism regulating the sexual disparity seen in SPX levels post-intervention exists should be further investigated using a larger sample size

    COSMO-RS based prediction for alpha-linolenic acid (ALA) extraction from microalgae biomass using room temperature ionic liquids (RTILS)

    Get PDF
    One of the essential fatty acids with therapeutic impacts on human health is known to be omega-3 polyunsaturated fatty acids (PUFA). More lately, ionic liquids (ILs) have received significant attention among scientists in overcoming the disadvantages of traditional solvents in biomass lipid extraction. However, the large pool of cations and anions possibly accessible will lead to a growing number of innovatively synthesized ILs. Nevertheless, the exhaustive measurement of all these systems is economically impractical. The conductive screening model for real solvents (COSMO-RS) is considered a precious approach with the availability of a few models to predict the characteristics of ILs. This work introduces the estimate of capacity values at infinite dilution for a range of ILs using COSMO-RS software as part of solid-liquid extraction. This favorable outcome presented that the capacity values of the IL molecules are extremely dependent on both anions and cations. Among the 352 combinations of cation/anion tested, short alkyl chain cations coupled with inorganic anions were found to be most efficient and therefore superior in the extraction method. Sulphate-, chloride-, and bromide-based ILs were found to have higher extraction capacities in contrast with the remainders, while propanoate revealed an extraordinary capacity when combined with ethyl-based cations. Eventually, the predicted results from COSMO-RS were validated through the experimentally calculated extraction yield of alpha-linolenic acid (ALA) compound from Nannochloropsis sp. microalgae. Three selected ILs namely [EMIM][Cl], [TMAm][Cl], and [EMPyrro][Br] were selected from COSMO-RS for empirical extraction purpose and the validation results pinpointed the good prediction capability of COSMO-RS
    corecore