676 research outputs found

    Selecting the Best Using Data Envelopment Analysis

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    One of the most important strengths of Data Envelopment Analysis, (DEA), is that it allows almost complete freedom in the way that each decision making unit, (DMU), evaluates itself relative to its peers. This tends to result in many DMUs receiving a high efficiency score. Particularly when DEA is applied in a decision making context, it may be desirable to select a single option rather than determining the set of efficient alternatives in ranking efficient DMU or to Assist selecting a best DMU. Several extensions to DEA have been proposed and used. This paper examines, compares, and integrates a variety of these methods. A less complicated application area is used to investigate the subtleties of DEA cross-efficiency

    Pancreatic ductal adenocarcinoma and chronic pancreatitis may be diagnosed by exhaled-breath profiles:a multicenter pilot study

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    Background: The diagnosis of pancreatic adenocarcinoma and chronic pancreatitis often rely on expensive and invasive diagnostic approaches, which are not always discriminative since patients with chronic pancreatitis and pancreatic adenocarcinoma may present with similar symptoms. Volatile organic compounds (VOCs) in expired breath, could be used as a non-invasive diagnostic biological marker for detection of pancreatic pathology. Detection and discrimination of pancreatic pathology with an electronic nose has not yet been reported. Purpose: The objective of this pilot study was to determine the diagnostic potential of an electronic nose to identify pancreatic adenocarcinoma and chronic pancreatitis by analyzing volatile organic compoundg (VOC) profiles in exhaled air. Patients and methods: In a multicenter study, the exhaled air of 56 chronic pancreatitis patients, 29 pancreatic adenocarcinoma patients, and 74 disease controls were analyzed using an electronic nose based on 3 metal oxide sensors (MOS). The measurements were evaluated utilizing an artificial neural network. Results: VOC profiles of chronic pancreatitis patients could be discriminated from disease controls with an accuracy of 0.87 (AUC 0.95, sensitivity 80%, specificity 92%). Also, VOC profiles of patients with pancreatic adenocarcinoma differed from disease controls with an accuracy of 0.83 (AUC 0.87, sensitivity 83%, specificity 82%). Discrimination between chronic pancreatitis and pancreatic adenocarcinoma showed an accuracy of 0.75 (AUC 0.83, sensitivity 83%, specificity 71%). Conclusion: An electronic nose may be a valuable diagnostic tool in diagnosis of pancreatic adenocarcinoma and chronic pancreatitis. The current study shows the potential of an electronic nose for discriminating between chronic pancreatitis, pancreatic adenocarcinoma and healthy controls. The results from this proof-of-concept study warrant external validation in larger cohorts

    The effect of racemic gossypol and AT-101 on angiogenic profile of OVCAR-3 cells: a preliminary molecular framework for gossypol enantiomers

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    To compare the effect of racemic gossypol with its (–)/(–) enantiomer (AT-101) on expression profiles of angiogenic molecules by mRNA levels in human ovarian cancer cell line OVCAR-3. Methods: Cell viability assay (2,3-bis (2-methoxy-4-nitro-5- sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide) was used to detect cytotoxicity of gossypol enantiomers. DNA fragmentation by an enzyme-linked immunosorbent (ELISA) assay was used to evaluate the rate of apoptosis. The mRNA expression levels of angiogenic molecules were investigated by Human Angiogenesis RT2 ProfilerTM PCR Array (SuperArray, Frederick, MD). Results: Both racemic form and AT-101 resulted in a significant cytotoxicity and induced apoptosis. This effect was observed in a dose- and time dependent manner. However, AT-101 was much more potent. In addition, the treatment of 10 μM of racemic gossypol alone and 3 μM of AT-101 alone resulted in significant down-regulation (≥ 3 fold) in mRNA levels of some pivotal angiogenic molecules in OVCAR-3, but altered gene profiles were different by the treatment of each enantiomer. Conclusion: The efficacy of two gossypol enantiomers in OVCAR-3 cells showed distinction. AT-101 was much more potent than racemic gossypol, not only by means of cell death and apoptosis, but also by modulation of angiogenic molecules released from OVCAR-3 cells. Further studies with endothelial cells should be done to verify the anti-angiogenic effect of gossypol enantiomers in cancer treatment

    Synthesis of Carboxymethyl Starch for increasing drilling mud quality in drilling oil and gas wells

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    This paper describes the impact of carboxymethyl starch preparation conditions on physicochemical properties of polysaccharide reagent, widely used as fluid loss reducing agent in drilling mud. Variation of the main parameters of carboxymethylation is researched in the experiment. The following conditions such as temperature and reaction time, amount of water, as well as ratio of NaOH to monochloracetic acid define the characteristics of carboxymethyl starch. The degree of substitution is defined for polysaccharides, as well as the characteristics of samples have been studied by infrared spectroscopy. Rheological characteristics and fluid loss indicator have been investigated to study the impact of the reagents on drilling mud quality

    Use of comparative data for integrated cancer services

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    Background: Comparative data are an important resource for management of integrated care. In 2001, the English Department of Health created 34 cancer networks, broadly serving populations of half to three million people, to coordinate cancer services across providers. We have investigated how national and regional routine data are used by the cancer network management teams.Methods: Telephone interviews using a standardised semi-structured questionnaire were conducted with 68 participants in 29 cancer network teams. Replies were analysed both quantitatively and qualitatively.Results: While most network teams had a formal information strategy, data were used ad hoc more than regularly, and were not thought to be as influential in network decision making as other sources of information. Data collection was more prominent in information strategies than data use. Perceptions of data usefulness were mixed and there were worries over data quality, relevance, and potential misuse. Participants were receptive to the idea of a new limited dataset collating comparative data from currently available routine data sources. Few network structural factors were associated with data use, perceptions of current data, or receptivity to a new dataset.Conclusion: Comparative data are underused for managing integrated cancer services in England. Managers would welcome more comparative data, but also desired data to be relevant, quality assured and contextualised, and for the teams to be better resourced for data use

    Finite-Element Modelling of Biotransistors

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    Current research efforts in biosensor design attempt to integrate biochemical assays with semiconductor substrates and microfluidic assemblies to realize fully integrated lab-on-chip devices. The DNA biotransistor (BioFET) is an example of such a device. The process of chemical modification of the FET and attachment of linker and probe molecules is a statistical process that can result in variations in the sensed signal between different BioFET cells in an array. In order to quantify these and other variations and assess their importance in the design, complete physical simulation of the device is necessary. Here, we perform a mean-field finite-element modelling of a short channel, two-dimensional BioFET device. We compare the results of this model with one-dimensional calculation results to show important differences, illustrating the importance of the molecular structure, placement and conformation of DNA in determining the output signal

    Boundary Spanners and Calculative Practices

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    This paper questions to what extent particular calculative practices used for inter organisational decision-making help or hinder boundary spanners meet performativity ideals. It uses programmatic rationalities of government as a framework to study reciprocity between them and the conditions of performativity. Empirical data was collected from health care commissioning spaces of English NHS. Data triangulation was achieved through documentary analysis, data collected through interviews, and observation notes taken in local commissioning meetings and national conferences. Findings revealed an apparent lack of reciprocity between programmatic rationality and calculative practices surrounding the commissioning activities of boundary spanners. As a consequence, in local commissioning situations boundary spanners with formal roles used calculative practices differently than semi-formal boundary spanners. Unlike their formal counterparts, who used only accounting information in their calculative practices, semi-formal boundary spanners incorporated non-accounting information and devised alternative calculative practices. In addition, while formal boundary spanners on NHS Committees used calculative practices in maintaining clear boundaries between commissioning and provider organisations, semi-formal boundary spanners observed made use of the data of both parties in order to reach inter organisational decisions. The study has three main contributions. First, it differentiates boundary spanners and explains differences in their interaction with calculative practices. Second, it introduces the concept of reciprocity to inter-organisational studies in accounting. Third, it shows how conditions of performativity reflected in micro settings influenced how semi-formal boundary spanners used calculative practices (and other supplementary information) to achieve performance ideals of government programmes

    Dexamethasone potentiates the antiangiogenic activity of docetaxel in castration-resistant prostate cancer

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    We sought to characterise whether dexamethasone (DEX) may enhance tumour response to docetaxel in in vitro and in vivo models of metastatic prostate cancer (CaP). In vitro experiments conducted on PC3 and human bone marrow endothelial cells (hBMECs) determined that administration of DEX (10 nM) reduced constitutive nuclear factor-κB (NF-κB) activity, decreasing interleukin (IL)-8, CXCL1 and VEGF gene expression in PC3 cells. Dexamethasone also attenuated docetaxel-induced NF-κB and activator protein-1 transcription and reduced docetaxel-promoted expression/secretion of IL-8 and CXCL1 in PC3 and hBMECs. Although DEX failed to enhance docetaxel cytotoxicity on PC3 cells, DEX potentiated the antiangiogenic activity of docetaxel in vitro, further reducing vessel area and vessel length in developing endothelial tubes (P<0.05). Docetaxel had a potent antiangiogenic activity in the dorsal skin flap-implanted PC3 tumours in vivo. Small blood vessel formation was further suppressed in tumours co-treated with docetaxel and DEX, substantiated by an increased average vessel diameter and segment length and a decreased number of branch points in the residual tumour vasculature (P<0.001). Our data show that DEX potentiates the antiangiogenic activity of docetaxel, suggesting a putative mechanism for the palliative and survival benefits of these agents in metastatic CaP
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