A Bayesian Approach to Parameter Inference in Queueing Networks

The application of queueing network models to real-world applications often involves the task of estimating the service demand placed by requests at queueing nodes. In this article, we propose a methodology to estimate service demands in closed multiclass queueing networks based on Gibbs sampling. Our methodology requires measurements of the number of jobs at resources and can accept prior probabilities on the demands. Gibbs sampling is challenging to apply to estimation problems for queueing networks since it requires one to efficiently evaluate a likelihood function on the measured data. This likelihood function depends on the equilibrium solution of the network, which is difficult to compute in closed models due to the presence of the normalizing constant of the equilibrium state probabilities. To tackle this obstacle, we define a novel iterative approximation of the normalizing constant and show the improved accuracy of this approach, compared to existing methods, for use in conjunction with Gibbs sampling. We also demonstrate that, as a demand estimation tool, Gibbs sampling outperforms other popular Markov Chain Monte Carlo approximations. Experimental validation based on traces from a cloud application demonstrates the effectiveness of Gibbs sampling for service demand estimation in real-world studies

A novel multiplex assay combining autoantibodies plus PSA has potential implications for classification of prostate cancer from non-malignant cases

<p>Abstract</p> <p>Background</p> <p>The lack of sufficient specificity and sensitivity among conventional cancer biomarkers, such as prostate specific antigen (PSA) for prostate cancer has been widely recognized after several decades of clinical implications. Autoantibodies (autoAb) among others are being extensively investigated as potential substitute markers, but remain elusive. One major obstacle is the lack of a sensitive and multiplex approach for quantifying autoAb against a large panel of clinically relevant tumor-associated antigens (TAA).</p> <p>Methods</p> <p>To circumvent preparation of phage lysates and purification of recombinant proteins, we identified B cell epitopes from a number of previously defined prostate cancer-associated antigens (PCAA). Peptide epitopes from cancer/testis antigen NY-ESO-1, XAGE-1b, SSX-2,4, as well as prostate cancer overexpressed antigen AMACR, p90 autoantigen, and LEDGF were then conjugated with seroMAP microspheres to allow multiplex measurement of autoAb present in serum samples. Moreover, simultaneous quantification of autoAb plus total PSA was achieved in one reaction, and termed the "A+PSA" assay.</p> <p>Results</p> <p>Peptide epitopes from the above 6 PCAA were identified and confirmed that autoAb against these peptide epitopes reacted specifically with the full-length protein. A pilot study was conducted with the A+PSA assay using pre-surgery sera from 131 biopsy-confirmed prostate cancer patients and 121 benign prostatic hyperplasia and/or prostatitis patients. A logistic regression-based A+PSA index was found to enhance sensitivities and specificities over PSA alone in distinguishing prostate cancer from nonmalignant cases. The A+PSA index also reduced false positive rate and improved the area under a receiver operating characteristic curve.</p> <p>Conclusions</p> <p>The A+PSA assay represents a novel platform that integrates autoAb signatures with a conventional cancer biomarker, which may aid in the diagnosis and prognosis of prostate cancer and others.</p

Contamination of Zayandeh Rud sediments with some heavy metals and chemical parameters

Background: The Zayandeh Rud, as a main river in the center of Iran, is the most important source of water for irrigation, industrial development and municipal use. The aim of this study was to evaluate the changes in contamination of Zayandeh Rud sediments. Materials and Methods: Samples were taken from the 6 stations along the river. Electrical conductivity, pH, organic matter and concentration of Pb, Cd and Ni were determined in the sediment samples.Results: The results showed a much sharper increase in electrical conductivity from station no.4 (Ejieh) to station no. 6 (Gavkhuni). Also, the sediment pH of Zayandeh Rud was alkaline with a minimum of 7.3 in station no. 2 (Chom) and a maximum of 7.9 in station no. 4. Concentration of Ni and content of organic matter increased from station no. 1 (Siosepol) to station no. 3 (Ziyar). The highest concentration of Pb was 72.1 mg/kg in station no. 2. Conclusion: According to the results of this study, concentration of Pb in urban areas was higher than the downstream. Concentration of Cd was 2 mg/kg in station no. 5 and in another stations was very low. Therefore, the sediments of the river are not contaminated with cadmium

Hydrotalcite as an Efficient and Reusable Catalyst for Acylation of Phenols, Amines and Thiols Under Solvent-free Conditions

A wide variety of alcohols, phenols, amines and thiols were efficiently acylated with carboxylic acid anhydrides and chlorides in the presence of Hydrotalcite under solvent-free conditions at room temperature in good to high yields. Eco-friendly conditions and reusability of the catalyst are the most important advantages of this protocol

One-step synthesis of silver nanostructures using Heracleum persicum fruit extract, their cytotoxic activity, anti-cancer and anti-oxidant activities

Bio-inspired techniques are used for synthesis in terms of application, green chemical research, facile, and eco-friendly chemistry study of silver nanostructures utilizing plant extracts as natural reducing/stabilization and solid adjuvants without the use of toxic and damaging reagents. The present study investigates the biosynthesis of Ag nanoparticles via the mediation of the methanolic extract of Heracleum persicum seeds, without utilizing any stabilizer or surfactant. These nanostructures were identified utilizing ultraviolet-visible spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, high-resolution transmission electron microscopy, Fourier-transform infrared spectroscopy and dynamic light scattering. The attributes of AgNPs versus usual human breast adenocarcinoma cell lines that is, Hs 281.T, MDA-MB-468, AU565 AU-565, MCF7, CAMA-1, SK-BR-3, NMU, and RBA were evaluated. The livability of breast adenocarcinoma cell line diminishes dose-dependently in the existence of AgNPs. After clinical studies, AgNPs can be used as a green drug in the treatment of human breast adenocarcinoma