Zap Q-Learning for Optimal Stopping Time Problems

The objective in this paper is to obtain fast converging reinforcement learning algorithms to approximate solutions to the problem of discounted cost optimal stopping in an irreducible, uniformly ergodic Markov chain, evolving on a compact subset of $\mathbb{R}^n$. We build on the dynamic programming approach taken by Tsitsikilis and Van Roy, wherein they propose a Q-learning algorithm to estimate the optimal state-action value function, which then defines an optimal stopping rule. We provide insights as to why the convergence rate of this algorithm can be slow, and propose a fast-converging alternative, the "Zap-Q-learning" algorithm, designed to achieve optimal rate of convergence. For the first time, we prove the convergence of the Zap-Q-learning algorithm under the assumption of linear function approximation setting. We use ODE analysis for the proof, and the optimal asymptotic variance property of the algorithm is reflected via fast convergence in a finance example

Diagnostic accuracy of TB-LAMP for pulmonary tuberculosis: a systematic review and meta-analysis.

BACKGROUND:The need for a rapid, molecular test to diagnose tuberculosis (TB) has prompted exploration of TB-LAMP (Eiken; Tokyo, Japan) for use in resource-limited settings. We conducted a systematic review to assess the accuracy of TB-LAMP as a diagnostic test for pulmonary TB. METHODS:We analyzed individual-level data for eligible patients from all studies of TB-LAMP conducted between Jan 2012 and October 2015 to compare the diagnostic accuracy of TB-LAMP with that of smear microscopy and Xpert MTB/RIF® using 3 reference standards of varying stringency. Pooled sensitivity and specificity and pooled differences in sensitivity and specificity were estimated using random effects meta-analysis. Study quality was evaluated using QUADAS-2. RESULTS:Four thousand seven hundred sixty individuals across 13 studies met eligibility criteria. Methodological quality was judged to be low for all studies. TB-LAMP had higher sensitivity than sputum smear microscopy (pooled sensitivity difference + 13·2, 95% CI 4·5-21·9%) and similar sensitivity to Xpert MTB/RIF (pooled sensitivity difference - 2·5, 95% CI -8·0 to + 2·9) using the most stringent reference standard available. Specificity of TB-LAMP was similar to that of sputum smear microscopy (pooled specificity difference - 1·8, 95% CI -3·8 to + 0·2) and Xpert MTB/RIF (pooled specificity difference 0·5, 95% CI -0·9 to + 1·8). CONCLUSIONS:From the perspective of diagnostic accuracy, TB-LAMP may be considered as an alternative test for sputum smear microscopy. Additional factors such as cost, feasibility, and acceptability in settings that continue to rely on sputum smear microscopy should be considered when deciding to adopt this technology. Xpert MTB/RIF should continue to be preferred in settings where resource and infrastructure requirements are adequate and where HIV co-infection or drug-resistance is of concern

PENGARUH TEMPERATUR TUANG TERHADAP SIFAT MEKANIS DAN MIKROSTRUKTUR ALUMINIUM A356 MENGGUNAKAN PENGECORAN METODE COOLING SLOPE

Penggunaan aluminium yang begitu luas dalam bidang teknik dikarenakan memiliki massa jenis yang ringan dan ketahanan korosi yang baik tetapi aluminium memiliki sifat mekanis yang masih perlu ditingkatkan khususnya aluminium yang diproduksi dengan menggunakan metode pengecoran. Pada proses pengecoran sangat banyak variabel yang akan mempengaruhi kekuatan aluminium yang salah satunya adalah temperatur tuang. Penelitian ini bertujuan untuk melihat pengaruh temperatur tuang terhadap sifat mekanis aluminium A356 yang meliputi kekerasan,impak,tarik,aus, serta mikrostruktur dengan menggunakan metode pengecoran tipe cooling slope. Cooling slope digunakan untuk mengalirkan alumunium yang sudah mencair ke dalam cetakan. Cooling slope ini sendiri mempunyai 5 sudut kemiringan, yaitu 15˚, 30˚, 45˚, 60˚,dan 75˚. Penelitian ini dilakukan dengan memvariasikan temperatur tuang 620˚C, 650˚C, 680˚C, 710˚C, dan 740˚C serta sudut dari cooling slope adalah 15˚ menggunakan cetakan permanen. Kekerasan tertinggi diperoleh pada variasi temperatur tuang 680˚C sebesar 52,8 BHN. Nilai impak tertinggi di dapat pada variasi temperatur tuang 710˚C sebesar 0,18 J/mm². Nilai uji tarik tertinggi diperoleh pada variasi temperatur tuang 680˚C sebesar 106,72 Mpa. Pengujian keausan dilakukan dengan metode pin on disk dengan variasi putaran 150 Rpm, 180 Rpm, dan 210 Rpm. Hasil photo mikro terlihat pada temperatur 680˚C distribus silikon di dalam matrik alumunium lebih merata dibandingkan dengan temperatur yang lainnya

Fabrication and Evaluation of Aceclofenac Buccal Patches using Musa Paradiasica Gum as Adhesive Polymer

Aceclofenac belongs to the drug class known as NSAIDs. It is normally indicated for the treatment of dental pain, rheumatoid arthritis, osteoarthritis and ankylosing spondylitis. It is selective cox-2 inhibitor. It has an extensive and highly variable hepatic first pass metabolism following oral administration having half life of 4 hours. The usual dose of Aceclofenac is 100 mg twice daily with systemic bioavailability of 40- 50% due to extensive “first-pass” metabolism and has a narrow absorption window. In order to prolong the drug release, an attempt was made to develop buccal drug delivery system for Aceclofenac in the form of matrix diffusion controlled BDDS. The polymers used in this study were a blend of HPMC and EUDRAGIT RL-100(F1-F5) and polymer combination of HPMC,EUDRAGIT and Musa Paradiasica natural gum polymer(F6-F10). The plasticizer used was Polyethylene glycol-400. Dimethyl Sulphoxide was used as permeation enhancer. The patches were prepared by solvent evporation method and the formulated patches were evaluated for various physicochemical parameters, in vitro release and compatibility studies. The percentage moisture and moisture absorption increased with an increase in the concentration of Musa Paradiasica gum polymer along with HPMC and EUDRAGIT R L 100. No significant difference in thickness among each group indicates that the patches were uniform throughout. The increase in the average weight was due to increase in the plasticizer concentration(F1-F5) and use of permeation enhancer (F6-F10). There was a slight increase in the folding endurance (F6-F10) due to the increase in the plasticizer concentration. There was no significant difference in the drug content among patches indicating the uniformity in drug content. Formulation variables such as polymer ratio, plasticizer and permeation enhancers were found to influence the in vitro drug release behaviour of the formulated patches. Increasing the concentration of hydrophobic polymers (EUDRAGIT and Musa paradiasica gum polymer) were found to increase the in vitro drug release of the formulated patches. From the studies performed, F10 formulation with HPMC to EUDRAGIT to Musa paradiasica gum polymer ratio 4:3:2 showed the best results and exhibited the cumulative percentage of drug release of 85.8 in 12 hrs. FTIR studies were performed and reported no abnormal peaks and thus it was concluded that there is no incompatibility between the drug and the polymer blends. An attempt was made to develop the complete buccal system of the drug by using the backing membrane and release liner. From this study it can be concluded that it is possible to design a buccal drug delivery system for Aceclofenac, where therapeutic efficacy and patient compliance are of prime importance.CONCLUSION : • Matrix type buccal patches of Aceclofenac have been successfully prepared by solvent evaporation method. • Aceclofenac, an NSAID was selected for the preparation of matrix buccal system. • Various ratios of HPMC,EUDRAGIT and Musa paradiasica were used as polymer blend for the preparation of buccal patches. • Polymeric matrix type Aceclofenac buccal patches were prepared by solvent evaporation method using combination of HPMC,EUDRAGIT and Musa paradiasica in varying ratio with plasticiser polyethylene glycol-400 and permeation enhancers Dimethyl sulphoxide, which exhibited good flexibility, proper physio-mechanical characteristics, handling properties and drug release. • Based on the physicochemical parameters and in vitro release studies, the F10 formulation with HPMC,EUDRAGIT and Musa paradiasica in the ratio 4:3:3 with PEG-400 and DMSO as a permeation enhancer showed the best results, which exhibited the cumulative percentage of drug release of 85.8% in 12 hrs. • The compatibility study by IR spectroscopy revealed that there were no physical and chemical interaction between the drug and polymers. • Based on the encouraging results, the Aceclofenac buccal patch is one of the best controlled drug delivery systems in the treatment of Rheumatoid arthritis, pain and inflamation where the drug is made available for an extended period of time, so frequency of administration can be minimized. • An attempt was made to develop the complete buccal system of the drug by using the backing membrane and release liner. From this study it can be concluded that it is possible to design a buccal drug delivery system for Aceclofenac, where therapeutic efficacy and patient compliance are of prime importance. However, long term pharmacokinetic and pharmacodynamic studies are needed to be undertaken to establish the usefulness of these patches

Unusual Radiographic Presentation of Pneumocystis Pneumonia in a Patient with AIDS.

Pneumocystis jirovecii pneumonia (PCP) typically presents as an interstitial and alveolar process with ground glass opacities on chest computed tomography (CT). The absence of ground glass opacities on chest CT is thought to have a high negative predictive value for PCP in individuals with AIDS. Here, we report a case of PCP in a man with AIDS who presented to our hospital with subacute shortness of breath and a nonproductive cough. While his chest CT revealed diffuse nodular rather than ground glass opacities, bronchoscopy with bronchoalveolar lavage and transbronchial biopsies confirmed the diagnosis of PCP and did not identify additional pathogens. PCP was not the expected diagnosis based on chest CT, but it otherwise fit well with the patient's clinical and laboratory presentation. In the era of combination antiretroviral therapy, routine prophylaxis for PCP, and increased use of computed tomography, it may be that PCP will increasingly present with nonclassical chest radiographic patterns. Clinicians should be aware of this presentation when selecting diagnostic and management strategies

Enzyme Production Using an Extremophilic Biocatalyst

Bio-detergents are useful in many markets because they contain enzymes that can break down proteins and in turn enhance stain removal. However, many of these enzymes deactivate at high temperatures so sterilization and stain removal must be done in two separate processes. This process produces extremozymes, enzymes derived from extremophilic microorganisms that have optimal activity and stability at harsh conditions, to be used in bio-detergents. The thermostable characteristics of this enzyme allow it to accomplish high levels of protein breakdown at temperatures conducive to sterilization. It is expected that this characteristic provides a 15% price premium over the leading incumbant. The extremophilic biocatalyst used for this process is Natronomonas pharaonis and the selected enzyme has optimal activity at 60℃ and pH 10.0. The target production rate is 4,500 MT per year with the final product being 87% and selling for $36.00/kg. According to a 10-year profitability analysis, the predicted IRR is 15$880,900. In the third year of production the ROI will be 17.36%