Multi Construction Research Articles

Hepatitis C virus DNA vaccines: a systematic review

BackgroundVaccination against HCV is an effective measure in reduction of virus-related public health burden and mortality. However, no prophylactic vaccine is available as of yet. DNA-based immunization is a promising modality to generate cellular and humoral immune responses. The objective of this study is to provide a systematic review of HCV DNA vaccines and investigate and discuss the strategies employed to optimize their efficacies.MethodsMEDLINE (PubMed), Web of Science, Scopus, ScienceDirect, and databases in persian language including the Regional Information Centre for Science & Technology (RICeST), the Scientific Information Database and the Iranian Research Institute for Information Science and Technology (IranDoc) were examined to identify studies pertaining to HCV nucleic acid vaccine development from 2000 to 2020.ResultsTwenty-seven articles were included. Studies related to HCV RNA vaccines were yet to be published. A variety of strategies were identified with the potential to optimize HCV DNA vaccines such as incorporating multiple viral proteins and molecular tags such as HBsAg and Immunoglobulin Fc, multi-epitope expression, co-expression plasmid utilization, recombinant subunit immunogens, heterologous prime-boosting, incorporating NS3 mutants in DNA vaccines, utilization of adjuvants, employment of less explored methods such as Gene Electro Transfer, construction of multi- CTL epitopes, utilizing co/post translational modifications and polycistronic genes, among others. The effectiveness of the aforementioned strategies in boosting immune response and improving vaccine potency was assessed.ConclusionsThe recent progress on HCV vaccine development was examined in this systematic review to identify candidates with most promising prophylactic and therapeutic potential.

Tabu Search and Perturbation Methods in the Construction of Supersaturated Designs

SYNOPTIC ABSTRACTWe adapt the columnwise-pairwise algorithm (CP) of Li and Wu (1997) to the construction of multi- and mixed-level supersaturated designs. One inherent difficulty associated with the use of many heuristic algorithms is premature convergence to a local optima. Meyer and Nachtsheim (1988) discussed the use of simulated annealing method for constructing D-optimal designs. As an extension to their work, this research proposes two modified CP algorithms: tabu-enhanced CP and CP with perturbation. The performance of the two methods is evaluated in the construction of multi-level supersaturated designs. Using these algorithms yields a class of supersaturated designs that is more efficient than existing designs in terms of the optimality criteria. Results are also compared with Fang, Lin, and Ma (2000). The application of the CP algorithms to mixed-level supersaturated designs is examined as well.

5@5 – a 5 GeV energy threshold array of imaging atmospheric Cherenkov telescopes at 5 km altitude

We discuss the concept and the performance of a powerful future ground-based astronomical instrument, 5@5 – a 5 GeV energy threshold stereoscopic array of several large imaging atmospheric Cherenkov telescopes (IACTs) installed at a very high mountain elevation of about 5 km a.s.l. – for the study of the γ-ray sky at energies from approximately 5 to 100 GeV, where the capabilities of both the current space-based and ground-based γ-ray projects are quite limited. With its potential to detect the “standard” EGRET γ-ray sources with spectra extending beyond several GeV in exposure times from 1 to 103 s, such a detector may serve as an ideal “gamma-ray timing explorer” for the study of transient non-thermal phenomena like γ-radiation from AGN jets, synchrotron flares of microquasars, the high energy (GeV) counterparts of gamma ray bursts, etc. 5@5 also would allow detailed γ-ray spectroscopy of persistent nonthermal sources like pulsars, supernova remnants, plerions, radiogalaxies, and others, with unprecedented for γ-ray astronomy photon statistics. The existing technological achievements in the design and construction of multi(1000)-pixel, high resolution imagers, as well as of large, 20 m diameter class multi-mirror dishes with rather modest optical requirements, would allow the construction of such a detector in the foreseeable future, although in the longer terms from the point of view of ongoing projects of 100 GeV threshold IACT arrays like HESS which is in the build-up phase. An ideal site for such an instrument could be a high-altitude, 5 km a.s.l. or more, flat area with a linear scale of about 100 m in a very arid mountain region in the Atacama desert of Northern Chile.