1,536 research outputs found
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Distributed diagnostics, prognostics and maintenance planning: Realizing industry 4.0
In this paper, a novel distributed yet integrated approach for diagnostics and prognostics is presented. An experimental study is conducted to validate the performance. Results showed that distributed prognostics give better performance in leaser computational time. Also, the proposed approach helps in making the results of the machine learning techniques comprehensible and more accurate. These results will be handy in arriving at predictive maintenance schedule considering the criticality of the system, the dependency of the components, available maintenance resources and confidence level in the results of the prognostic.Royal Academy of Engineering London, UK (IAPP 18-19/31
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Product quality driven auto-prognostics: Low-cost digital solution for SMEs
Setting out existing prognostics solutions in small and medium enterprises (SMEs) is accompanied by challenges. These include employing expensive sensors, acquisition systems; and attending geometric limitations. Additionally, these solutions call for a specialist to take on feature engineering, machine learning algorithm selection, etc. Presented in this paper is a low-cost digital solution (intelligently integrate cost-cutting off-the-shelf technologies) for SMEs via product quality driven auto-prognostics. First, we develop upon existing solutions by addressing their drawbacks viz. cost, geometric limitations via a new product quality-centered condition monitoring strategy. Every SME must investigate the quality of their products, and therefore the authors believe this to be a low-cost solution. Next, the proposed solution integrates automated machine learning via Auto-WEKA, an off-the-shelf open-source technology. Lastly, the practical advantages of the proposed solution over the existing sensor-based solution were investigated via a case study. Results depict that this low-cost prognostics solution is vital for maintenance planning in SMEs.Royal Academy of Engineering London, UK (IAPP 18-19/31)
COMPARISON OF RP-HPLC AND UV SPECTROPHOTOMETRIC METHODS FOR ESTIMATION OF HALOPERIDOL IN PURE AND PHARMACEUTICAL FORMULATION
An accurate, precise, sensitive and reproducible High-performance liquid chromatographic (HPLC) and UV spectrophotometric methods were developed and validated for the quantitative determination of haloperidol (HPD) in bulk drug and pharmaceutical formulation. Different analytical performance parameters such as linearity, precision, accuracy, specificity, limit of detection (LOD) and limit of quantification (LOQ) were determined according to International Conference on Harmonization ICH Q2B guidelines. The RP-HPLC method was developed by the isocratic technique on a reversed-phase Thermo C18 (250 × 4.6 mm, 5µm) column with mobile phase consisting of Methanol: Acetonitrile (50:50v/v) at flow rate of 1.0 ml/min. The retention time for HPD was 2.238±0.3min. The UV spectrophotometric determinations were performed at 244 nm using 80% methanol as a solvent. The linearity range for HPD was 5-25 μg/ml for both HPLC and UV method. The linearity of the calibration curves for each analyte in the desired concentration range was good (r2 >0.999) by both the HPLC and UV methods. The method showed good reproducibility and recovery with percent relative standard deviation less than 2%. Moreover, the accuracy and precision obtained with HPLC co-related well with the UV method which implied that UV spectroscopy can be a cheap, reliable and less time consuming alternative for chromatographic analysis. The proposed methods are highly sensitive, precise and accurate and hence successfully applied for determining the assay and in vitro dissolution of a marketed formulation.
Keywords: HPLC, UV Spectrophotometry, Haloperidol, Pharmaceutical formulation, Method validation, Quantitative analysi
Analytical Method Development and Validation for the Simultaneous Estimation of Aspirin, Clopidogrel and Rosuvastatin in Pharmaceutical Dosage Form
A new, simple, novel, accurate, precise, reliable, rapid and linear reverse phase high-performance liquid chromatography (RP-HPLC) method was developed and fully validated for simultaneous qualitative and quantitative estimation of Rosuvastatin (ROS), Clopidogrel (CLOP) and Aspirin (ASP) in bulk and pharmaceutical dosage form as per International Conference on Harmonization (ICH) guidelines. In the present work, good chromatographic separation was achieved by isocratic method using a Hypersil BDS C18 column (250 mm ×4.6, 5 μm) and a mobile phase consisting of KH2Po4 buffer pH-6.0: acetonitrile in the ratio 60:40, at a flow rate of 1 ml/min. The effluents obtained were monitored at 242nm with the UV-visible detector. The calibration curves obtained were linear (r2=0.999) over the concentration range of 7.5-22.5μg/ml and 1-3μg/ml for CLOP, ASP and ROS respectively. A run time of 7.0 minutes for each sample made it possible to analyze more than 200 samples per day. The retention time of ASP, CLOP and ROS was found to be 3.103 min, 4,277 min and 5.707 min respectively. The high recovery values (99%-101%) indicate a satisfactory accuracy. The low percent relative standard deviation (% RSD) values in the precision study reveal that the method is precise therefore the method can be used for routine monitoring of CLOP, ASP and ROS in industry in the assay of bulk drug and dosage form.
Keywords: RP-HPLC, Rosuvastatin, Clopidogrel, Aspirin, Method validation, ICH guidelines
Macrodystrophia lipomatosa involving multiple nerves
Macrodystrophia lipomatosa (MDL), a rare congenital disorder, is considered by some to be a localized form of Proteus syndrome. The implication of the PTEN (phosphatase and tensin homolog deleted on chromosome 10) gene in both strengthens this belief. We present a case who had MDL in multiple nerve territories—all on the same side of the body—with hypertrophy of mainly fibroadipose tissue throughout their distribution, thus pointing to a form of localized hemihypertrophy; both hemihypertrophy and lipomatous tumors are components of Proteus syndrome
A statistical framework to evaluate virtual screening
<p>Abstract</p> <p>Background</p> <p>Receiver operating characteristic (ROC) curve is widely used to evaluate virtual screening (VS) studies. However, the method fails to address the "early recognition" problem specific to VS. Although many other metrics, such as RIE, BEDROC, and pROC that emphasize "early recognition" have been proposed, there are no rigorous statistical guidelines for determining the thresholds and performing significance tests. Also no comparisons have been made between these metrics under a statistical framework to better understand their performances.</p> <p>Results</p> <p>We have proposed a statistical framework to evaluate VS studies by which the threshold to determine whether a ranking method is better than random ranking can be derived by bootstrap simulations and 2 ranking methods can be compared by permutation test. We found that different metrics emphasize "early recognition" differently. BEDROC and RIE are 2 statistically equivalent metrics. Our newly proposed metric SLR is superior to pROC. Through extensive simulations, we observed a "seesaw effect" – overemphasizing early recognition reduces the statistical power of a metric to detect true early recognitions.</p> <p>Conclusion</p> <p>The statistical framework developed and tested by us is applicable to any other metric as well, even if their exact distribution is unknown. Under this framework, a threshold can be easily selected according to a pre-specified type I error rate and statistical comparisons between 2 ranking methods becomes possible. The theoretical null distribution of SLR metric is available so that the threshold of SLR can be exactly determined without resorting to bootstrap simulations, which makes it easy to use in practical virtual screening studies.</p
First case of childhood Takayasu arteritis with renal artery aneurysms
Takayasu arteritis is a large vessel systemic granulomatous vasculitis characterized by stenosis or obliteration of large and medium sized arteries. It commonly involves elastic arteries such as the aorta and its main branches. Renal artery involvement is rare and has not been reported in a child. We report a 12-year-old boy with Takayasu arteritis who developed severe hypertension, proteinuria, microscopic hematuria and renal dysfunction. Conventional angiography demonstrated aneurysms of both renal arteries and multiple microaneurysms of the superior mesenteric artery. This case report illustrates that the children with Takayasu arteritis can develop renal involvement resulting in hematuria, proteinuria and even renal failure
Combinatorial Computational Approaches to Identify Tetracycline Derivatives as Flavivirus Inhibitors
Limited structural information of drug targets, cellular toxicity possessed by lead compounds, and large amounts of potential leads are the major issues facing the design-oriented approach of discovering new leads. In an attempt to tackle these issues, we have developed a process of virtual screening based on the observation that conformational rearrangements of the dengue virus envelope protein are essential for the mediation of viral entry into host cells via membrane fusion. Screening was based solely on the structural information of the Dengue virus envelope protein and was focused on a target site that is presumably important for the conformational rearrangements necessary for viral entry. To circumvent the issue of lead compound toxicity, we performed screening based on molecular docking using structural databases of medical compounds. To enhance the identification of hits, we further categorized and selected candidates according to their novel structural characteristics. Finally, the selected candidates were subjected to a biological validation assay to assess inhibition of Dengue virus propagation in mammalian host cells using a plaque formation assay. Among the 10 compounds examined, rolitetracycline and doxycycline significantly inhibited plaque formation, demonstrating their inhibitory effect on dengue virus propagation. Both compounds were tetracycline derivatives with IC(50)s estimated to be 67.1 µM and 55.6 µM, respectively. Their docked conformations displayed common hydrophobic interactions with critical residues that affected membrane fusion during viral entry. These interactions will therefore position the tetracyclic ring moieties of both inhibitors to bind firmly to the target and, subsequently, disrupt conformational rearrangement and block viral entry. This process can be applied to other drug targets in which conformational rearrangement is critical to function
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