Langevin Diffusion: An Almost Universal Algorithm for Private Euclidean (Convex) Optimization

In this paper we revisit the problem of differentially private empirical risk minimization (DP-ERM) and stochastic convex optimization (DP-SCO). We show that a well-studied continuous time algorithm from statistical physics called Langevin diffusion (LD) simultaneously provides optimal privacy/utility tradeoffs for both DP-ERM and DP-SCO under $\epsilon$-DP and $(\epsilon,\delta)$-DP. Using the uniform stability properties of LD, we provide the optimal excess population risk guarantee for $\ell_2$-Lipschitz convex losses under $\epsilon$-DP (even up to $\log n$ factors), thus improving on Asi et al. Along the way we provide various technical tools which can be of independent interest: i) A new R\'enyi divergence bound for LD when run on loss functions over two neighboring data sets, ii) Excess empirical risk bounds for last-iterate LD analogous to that of Shamir and Zhang for noisy stochastic gradient descent (SGD), and iii) A two phase excess risk analysis of LD, where the first phase is when the diffusion has not converged in any reasonable sense to a stationary distribution, and in the second phase when the diffusion has converged to a variant of Gibbs distribution. Our universality results crucially rely on the dynamics of LD. When it has converged to a stationary distribution, we obtain the optimal bounds under $\epsilon$-DP. When it is run only for a very short time $\propto 1/p$, we obtain the optimal bounds under $(\epsilon,\delta)$-DP. Here, $p$ is the dimensionality of the model space. Our work initiates a systematic study of DP continuous time optimization. We believe this may have ramifications in the design of discrete time DP optimization algorithms analogous to that in the non-private setting, where continuous time dynamical viewpoints have helped in designing new algorithms, including the celebrated mirror-descent and Polyak's momentum method.Comment: Added a comparison to the work of Asi et a

Detection of NP, N3 and N7 antibodies to avian influenza virus by indirect ELISA using yeast-expressed antigens

<p>Abstract</p> <p>Background</p> <p>Avian influenza viruses, belonging to the family Orthomyxoviridae, possess distinct combinations of hemagglutinin (H) and the neuraminidase (N) surface glycoproteins. Typing of both H and N antigens is essential for the epidemiological and surveillance studies. Therefore, it is important to find a rapid, sensitive, and specific method for their assay, and ELISA can be useful for this purpose, by using recombinant proteins.</p> <p>Results</p> <p>The nucleoprotein (NP) and truncated neuraminidase subtype 3 and 7 of avian influenza virus (AIV) were expressed in <it>Saccharomyces cerevisiae </it>and used to develop an indirect enzyme-linked immunosorbent assay for antibody detection. The developed assays were evaluated with a panel of 64 chicken serum samples. The performance of NP-ELISA was compared with the commercially available ProFlok^®AIV ELISA kit. The results showed comparable agreement and sensitivity between the two tests, indicating that NP-ELISA assay can be used for screening the influenza type A antibody in AIV infected birds. The N3 and N7- ELISAs also reacted specifically to their type specific sera and did not exhibit any cross-reaction with heterologous neuraminidase subtype specific sera.</p> <p>Conclusion</p> <p>The study demonstrates the expression of the NP, N3, and N7 proteins of AIV in yeast (<it>S. cerevisiae</it>) and their application in developing an indirect ELISA for detecting NP, N3 and N7 antibodies from AIV-infected chicken sera. The described indirect ELISAs are rapid, sensitive, specific and can be used as promising tests during serological surveillance.</p

Production of bio-gas (In urban areas using different types of wastes)

The focus of the research paper is to investigate the importance of biogas as an alternative energy sources in urban area. Urban waste, including wastewater treatment plants, food waste from households and businesses, yard clippings, human wastes, vegetable market wastes, and non-recyclable paper, will create biogas under the right conditions. Food waste from grocery stores, restaurants, cafeterias and homes contains energy and valuable nutrients. These wastes of specific area should collect in single tank and use them in bio-gas production

Analyzing Drug Release Kinetics from Water-Soluble Polymers

The ability to develop predictive mathematical models of therapeutic release from pharmaceutical formulations has enormous potential to enhance our understanding of such systems and improve the controlled release of the payload. The current work describes the development and testing of a one-dimensional model of drug transport from amorphous, swelling/dissolving polymers. Model parameters such as the diffusivities of water and drug, the initial loading of the drug, the polymer dissolution rate, drug-polymer interactions, and the tablet thickness were varied, demonstrating the ability to tune the release to be controlled by either drug diffusion or polymer chain disentanglement. In addition, predictions of the concentration profiles of water and drug within the gel layer, the locations of the erosion and swelling boundaries, and gel layer thickness were obtained for diffusion- and disentanglement-controlled release. To highlight the generalizability of this model, multiple parameters were varied, and it was shown that increasing the diffusivities of water and drug and the initial drug loading and decreasing the polymer dissolution rate sufficiently resulted in diffusion-controlled release. The model was fit to experimental data for a model tablet system comprising of sodium diclofenac entrapped in a poly(vinyl pyrrolidone) matrix and yielded physically meaningful values of the model parameters. The work presented here demonstrates the predictive power of the model for rapid and rational design of future pharmaceutical formulations for controlled drug delivery

Kinetics of Inclusion Body Formation and Its Correlation with the Characteristics of Protein Aggregates in Escherichia coli

The objective of the research was to understand the structural determinants governing protein aggregation into inclusion bodies during expression of recombinant proteins in Escherichia coli. Recombinant human growth hormone (hGH) and asparaginase were expressed as inclusion bodies in E.coli and the kinetics of aggregate formation was analyzed in details. Asparaginase inclusion bodies were of smaller size (200 nm) and the size of the aggregates did not increase with induction time. In contrast, the seeding and growth behavior of hGH inclusion bodies were found to be sequential, kinetically stable and the aggregate size increased from 200 to 800 nm with induction time. Human growth hormone inclusion bodies showed higher resistance to denaturants and proteinase K degradation in comparison to those of asparaginase inclusion bodies. Asparaginase inclusion bodies were completely solubilized at 2–3 M urea concentration and could be refolded into active protein, whereas 7 M urea was required for complete solubilization of hGH inclusion bodies. Both hGH and asparaginase inclusion bodies showed binding with amyloid specific dyes. In spite of its low β-sheet content, binding with dyes was more prominent in case of hGH inclusion bodies than that of asparaginase. Arrangements of protein molecules present in the surface as well as in the core of inclusion bodies were similar. Hydrophobic interactions between partially folded amphiphillic and hydrophobic alpha-helices were found to be one of the main determinants of hGH inclusion body formation. Aggregation behavior of the protein molecules decides the nature and properties of inclusion bodies

Science Attitudes and Knowledge among Preclinical Medical Students in Pokhara, Nepal

Knowledge of science and the scientific method are important in learning about and using evidence-based medicine in practice. Courses in research methodology have been introduced for both medical students and practicing doctors. In Pokhara, the basic science subjects are taught in an integrated manner during the first four semesters of the undergraduate medical course. Studies on students’ attitudes towards and knowledge of science are lacking in medical colleges in Nepal. Hence the study was carried out to obtain information on students’ attitude towards and knowledge of science and scientific methodology among preclinical medical students and note the association, if any, of students’ attitudes and their demographic characteristics. The study was carried out in March 2005 among the students of the first four semesters at the Manipal College of Medical Sciences, Pokhara, Nepal using a questionnaire developed by Hren and coworkers. Two hundred and twenty students (overall response rate 73.3%) successfully completed the questionnaire. Seventy- five respondents were Nepalese, 115 were Indians, 27 were Sri Lankans and 3 belonged to other nationalities. The X±SD total attitude score was 147.4±10.8 (neutral score 135). The X±SD scores on the subscales, value of science to humanity, value of scientific methodology and value of science to medicine were 51.3±5.4, 39.6±3.7 and 58.5±5.9 (neutral scores were 36, 51 and 48 respectively). The knowledge score measured using a set of 8 multiple choice questions was 3.3±1.4. The attitude scores were lower and the knowledge score was comparable to that reported previously in a study in Croatia but higher than that reported from Southeast Europe

Formulation and Evaluation of Tropicamide loaded Niosomes

Tropicamide is an antimuscarinic drug used in eye disease. The niosomal vesicular drug delivery system facilitate the permeation of drug through the cornea because of the micron/nano size of vesicles containing drugs, which will increase the corneal penetration of drug, and increase the residence time of formulation in ocular cavity that result to increase the bioavailability of drug. Tropicamide loaded Niosomes by investigating the relationship between drug/Nonionic surfactant ratio were successfully prepared by thin film hydration method and compare the result of different grade of span used (20,40,60) with different ratio of cholesterol. niosomes were evaluated for particle size ,drug entrapment efficiency, drug content ,corneal permeation study and in–vitro drug release. Respectively as a result the niosomes designed showed nearly spherical particles with a mean particle size 156.3nm. Niosomes prepared using cholesterol and span 60 in the ratio (1:1) f9 shoed higher entrapment efficiency (84.35%) in-vitro drug release (94.02%) was optimized. Keywords: Niosomes, in-situ gel, vesicles, ocular cul-de-sac, viscoelastic gel

Yttrium Enhanced Glass-Forming Ability of Zr-Based Metallic Glasses

803-810Thermodynamic behavior of Zr56-xCo28Al16Yx (x = 0, 2, 7, 10 at. %) bulk metallic glass-forming alloys has been studied using an analytical approach where some of the key thermodynamic quantities such as ΔH, ΔS and ΔG have been estimated using a hyperbolic temperature dependence of specific heat difference ΔCp in the supercooled liquid region. The study is focused on understanding the effect of yttrium (Y) doping on the thermodynamics of the alloys in the supercooled region and on the glass-forming ability (GFA) of these alloys. The analytical approach has been found to give estimates of ΔG in a wide supercooled liquid region which is in excellent agreement with the experimental results. Estimated ΔG values are found to be minimum for Y concentration of 7% and 10% which is consistent with the observed high GFA for these compositions. Fundamental elemental properties such as atomic size, electronegativity, the heat of mixing have been found to play an important role in governing the thermodynamics of the alloys in the supercooled liquid region

Yttrium Enhanced Glass-Forming Ability of Zr-Based Metallic Glasses

Thermodynamic behavior of Zr56-xCo28Al16Yx (0, 2, 7, 10) bulk metallic glass-forming alloys has been studied using an analytical approach where some of the key thermodynamic quantities such as ΔH, ΔS and ΔG has been estimated using a hyperbolic temperature dependence of specific heat difference ΔCp in the supercooled liquid region. The study is focused on understanding the effect of Yttrium-doping on the thermodynamics of the alloys in the supercooled region and on the glass-forming ability of these alloys. The analytical approach has been found to give estimates of ΔG in a wide supercooled liquid region in excellent agreement with the experimental results. Estimated ΔG values are found to be minimum for Y concentration of 7 and 10% which is consistent with the observed high GFA for these compositions. Fundamental elemental properties such as atomic size, electronegativity, the heat of mixing have been found to play an important role in governing the thermodynamics of the alloys in the supercooled liquid region

A STUDY ON PATTERN OF ALCOHOL USE USING AUDIT AMONG THE COLLEGE STUDENTS IN A MEDICAL COLLEGE OF NORTH INDIA

ABSTRACT Background: Alcohol and other substance use by medical students poses risks to them and can also have serious consequences on their effectiveness and fitness to practise as tomorrow&apos;s doctors. The aim of the study was to find out the prevalence of alcohol use among the undergraduates of Rohilkhand Medical College, Bareilly and the factors affecting its use