1,173 research outputs found
Robust decentralized authentication for public keys and geographic location:
No full textAuthentication has traditionally been done either in a decentralized manner with human assistance or automatically through a centralized security infrastructure. In the security infrastructure approach, a central trusted authority takes on the responsibility of authenticating participants within its domain of control. While the security infrastructure approach works well in traditional organizations, it does not address the needs of open membership systems.
We propose automatic decentralized authentication mechanisms for peer-to-peer systems, email systems, and ad-hoc networks. Our byzantine fault tolerant public-key authentication protocol (BPKA) provides decentralized authentication to peer-to-peer systems with honest majority. Authentication is done over an insecure asynchronous network without using trusted third parties or human input. We also authenticate public keys in the email environment through our social-group key authentication protocol (SGKA). The protocol provides end-to-end authentication at the email client without using infrastructure or centralized authorities. Finally, location authentication in ad-hoc networks is proposed through our geographical secure path routing protocol (GSPR). The protocol authenticates geographic locations of anonymous nodes in order to provide location authentication and anonymity simultaneously.Ph.D.Includes bibliographical references (p. 121o-128)by Vivek Patha
A comprehensive review of synthetic strategies and SAR studies for the discovery of PfDHODH inhibitors as antimalarial agents. Part 1: triazolopyrimidine, isoxazolopyrimidine and pyrrole-based (DSM) compounds
No full textOne of the deadliest infectious diseases, malaria, still has a significant impact on global morbidity and mortality. Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH) catalyzes the fourth step in de novo pyrimidine nucleotide biosynthesis and has been clinically validated as an innovative and promising target for the development of novel targeted antimalarial drugs. PfDHODH inhibitors have the potential to significantly slow down parasite growth at the blood and liver stages. Several PfDHODH inhibitors based on various scaffolds have been explored over the past two decades. Among them, triazolopyrimidines, isoxazolopyrimidines, and pyrrole-based derivatives known as DSM compounds showed tremendous potential as novel antimalarial agents, and one of the triazolopyrimidine-based compounds (DSM265) was able to reach phase IIa clinical trials. DSM compounds were synthesized as PfDHODH inhibitors with various substitutions based on structure-guided medicinal chemistry approaches and further optimised as well. For the first time, this review provides an overview of all the synthetic approaches used for the synthesis, alternative synthetic routes, and novel strategies involving various catalysts and chemical reagents that have been used to synthesize DSM compounds. We have also summarized SAR study of all these PfDHODH inhibitors. In an attempt to assist readers, scientists, and researchers involved in the development of new PfDHODH inhibitors as antimalarials, this review provides accessibility of all synthetic techniques and SAR studies of the most promising triazolopyrimidines, isoxazolopyrimidines, and pyrrole-based PfDHODH inhibitors
Conservational Analysis of Influenza A Virus RNA-dependent RNA Polymerase
No full textCompeting Interests: The authors have declared that no competing interests exist. Copyright: 2015 Darapaneni V et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. *Correspondence to: Vivek Darapaneni, Department of virology and computational biochemistry, Sake
sj-pdf-1-ajs-10.1177_03635465231180323 – Supplemental material for Efficacy and Safety of Stempeucel in Osteoarthritis of the Knee
No full textSupplemental material, sj-pdf-1-ajs-10.1177_03635465231180323 for Efficacy and Safety of Stempeucel in Osteoarthritis of the Knee by Pawan Kumar Gupta, Sunil Maheshwari, Joe Joseph Cherian, Vijay Goni, Arun Kumar Sharma, Sujith Kumar Tripathy, Keerthi Talari, Vivek Pandey, Parag Kantilal Sancheti, Saurabh Singh, Syamasis Bandyopadhyay, Naresh Shetty, Surendra Umesh Kamath, Purohit Sharad Prahaldbhai, Jijy Abraham, Suresh Kannan, Samatha Bhat, Shivashankar Parshuram, Vinayaka Shahavi, Akhilesh Sharma, Nikhil N. Verma and Uday Kumar in The American Journal of Sports Medicine</p
Debt maturity and firm performance : a panel study of Indian companies
Get PDFEconomic policy makers traditionally hold the view that, because of imperfections in capital markets, a shortage of long-term finance acts as a barrier to industrial performance and growth. Long term finance is thought to allow firms to invest in more productive technologies, even when they do not produce immediate payoffs, without fear of premature liquidation. As a result, special state-supported term-lending institutions have been established, especially in developing countries. But some believe that short-term finance may offer better incentives because it allows suppliers of finance to monitor and control firms more effectively, thus improving the firms'performance. The authors empirically investigate the determinants and consequences of the term structure of debt. Using a rich panel of data on privately owned companies in India, they also examine the influence of debt maturity structures on those firm's performance, especially on productivity. The results are not conclusive, but seem to support conventional beliefs about the importance of long term finance to firm performance. Heavy leveraging, however, has a strong negative impact on productivity. They base their econometric evidence on estimates of a maturity equation and of a production function augmented by financial variables. The data on which these results are based have been generated by a financial system in which there is little competition, in which state-owned financial institutions are not guided by the profit motive and have no control over interest rates, so one cannot say whether short term finance would have been more beneficial in a less regulated system. Moreover, by the end of the 1980s, the capital base of India's government-owned financial institutions had been severely eroded and they carried a heavy burden of nonperforming assets. This means that the benefits of long term finance must be weighed against the costs.Banks&Banking Reform,Financial Intermediation,Economic Theory&Research,Municipal Financial Management,Environmental Economics&Policies
Simple and low energy consuming synthesis of cyanate ester functional naphthoxazines and their properties
Get PDFNaphthoxazines functionalized with a cyanate ester group are synthesized in high yield under moderate conditions, including room temperature synthesis, compared with general benzoxazine synthesis. Additionally, this synthesis can shorten reaction pathways for another cyanate ester functional benzoxazine whose polymer exhibits higher thermal properties than general polybenzoxazines. Catalytic polymerization evaluated by differential scanning calorimetry (DSC) indicates multiple exotherm maxima, seemingly including cyanate ester trimerization and polymerization of naphthoxazine. The nature of each exotherm is studied by Fourier transform infrared spectroscopy (FT-IR). Furthermore, their observed exothermic temperatures are lower than those of the reported normal benzoxazines, dicyanate ester blends and cyanate ester functional benzoxazines. Thermal properties determined by thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA), such as the char yield and glass transition temperature, are relatively high compared to those of ordinary polybenzoxazines, and polymerized blends of benzoxazines and dicyanate esters.Fil: Ohashi, Seishi. Case Western Reserve University; Estados UnidosFil: Pandey, Vivek. Case Western Reserve University; Estados UnidosFil: Rodriguez Arza, Carlos. Case Western Reserve University; Estados UnidosFil: Froimowicz, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; Argentina. Case Western Reserve University; Estados UnidosFil: Ishida, Hatsuo. Case Western Reserve University; Estados Unido
Lattice approximation in the stochastic quantization of ([phi]4̳)2̳fields
No full textCaption title. "August 1988." On the title page, the bracketed word in the title appears as the Greek mathematical symbol representing [phi], the numeral four preceded by a double underscore appears as superscript, and the numeral two preceded by a double underscore appears as subscript.Includes bibliographical references.The research of the second author was supported in part by the U.S. Army Research Office, contract DAAL03-86-K-0171 The research of the second author was supported in part by the Air Force Office of Scientific Research under contract AFOSR-85-0227by Vivek S. Borkar, Sanjoy K. Mitter
Recent advances in the production of value added chemicals and lipids utilizing biodiesel industry generated crude glycerol as a substrate - Metabolic aspects, challenges and possibilities: An overview
No full textOne of the major ecological concerns associated with biodiesel production is the generation of waste/
crude glycerol during the trans-esterification process. Purification of this crude glycerol is not economically
viable. In this context, the development of an efficient and economically viable strategy would be
biotransformation reactions converting the biodiesel derived crude glycerol into value added chemicals.
Hence the process ensures the sustainability and waste management in biodiesel industry, paving a path
to integrated biorefineries. This review addresses a waste to wealth approach for utilization of crude glycerol
in the production of value added chemicals, current trends, challenges, future perspectives, metabolic
approaches and the genetic tools developed for the improved synthesis over wild type
microorganisms were described
On a 3GPP ray-based spatial channel model for MIMO system emulation: implementation and evaluation
No full textThe mitigation of random effects in a wireless communication channel is a problem considered for many years. In the present day context, given the ever increasing need for, and growth of, bandwidth intensive applications like streaming wireless HD video on fast moving user equipment (UEs, i.e., user communication devices), this issue has intensified from being a theoretical pursuit to a must-be-solved practical endeavor. In that regard, the ability to accurately model the outdoor (or indoor) propagation conditions in a laboratory setting becomes vital to validating state-of-the-art wireless standards and the devices that derive from them. Laboratory-based analysis is a significant catalyst in reducing the time-to-market for telecom equipment manufacturers. Modeling a wireless channel has been a topic under quite a bit of study. This has progressed from the Jakes model developed for single antenna systems to the correlation and ray-based models used for multiple antenna systems. The models prescribed by the 3rd Generation Partnership Project (3GPP) in its standards, like the ray-based model, aim to realistically reproduce channel environments in software and hardware, by incorporating all the variables that characterize any particular fading scenario. In this thesis, the technical report produced by 3GPP detailing the Spatial Channel Modeling (SCM) for multiple input multiple output (MIMO) simulations is followed closely as a basis for developing a real-time channel emulator on a National Instruments (NI) based Real Time (RT) Platform. First, a general purpose channel emulator is described in terms of its structure and functionality and currently known channel models are briefly investigated. Next, the spatial channel model in the standard is described in detail along with the reasons for choosing to use it in the thesis. All the parameters involved are defined, and the formula for constructing the channel is carefully investigated. Next, the channel emulator built on the National Instruments LabVIEW platform is described along with both the changes and modifications made to the design parameters so as to adapt it to the operating constraints of the RT platform. The spatial and temporal characteristics of the model are also described and plotted. Finally, the model is tested for reliability by methodically changing the various channel parameters and observing their effects on an Orthogonal Frequency Division Multiplexing (OFDM) test vector by generating BER performance plots in MATLAB. Diversity schemes are also employed to improve rate performance.M.S.Includes bibliographical referencesby Sabarish Karthik Vivek Sarath
RETRACTED: Water hyacinth a potential source for value addition: An overview
No full textWater hyacinth a fresh water aquatic plant is considered as a noxious weed in many parts of the world since it grows very fast and depletes nutrients and oxygen from water bodies adversely affecting the growth of both plants and animals. Hence conversion of this problematic weed to value added chemicals and fuels helps in the self-sustainability especially for developing countries. The present review discusses the various value added products and fuels which can be produced from water hyacinth, the recent research and developmental activities on the bioconversion of water hyacinth for the production of fuels and value added products as well as its possibilities and challenges in commercialization. (C) 2017 Elsevier Ltd. All rights reserved.GR-G
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