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51.
This paper shows a secured key-based (k, n) threshold cryptography scheme, where key as well as secret data is shared among set of participants. In this scheme, each share has some bytes missing and these missing bytes can be recovered from a set of exactly k shares, but not less than k. Therefore, each share contains partial secret information which is also encrypted by DNA encoding scheme. Additionally, this paper introduces a concept, where each share information size is varied. More precisely, each share contains a different percentage of secret information and which is strongly dependent on the key. Moreover key sensitivity analysis and statistical analysis prove the robustness against different cryptanalysis attacks and thus ensures high acceptability for information security requirements. 相似文献
52.
Gold nanoparticles (AuNPs) of about 5 nm in diameter were biosynthesized at room temperature (300 K). The PVA/2.5 wt% KH2PO4 or KDP composite film and PVA/2.5 wt% KDP/AuNPs nanocomposite films with different concentrations of AuNPs were prepared. Interestingly, addition of 0.05 wt% of AuNPs to the PVA/2.5 wt% KDP percolative composite film destroys percolative behavior of this composite film. Furthermore, the PVA/2.5 wt% KDP/0.05 wt% AuNPs nanocomposite film exhibited high room temperature dielectric permittivity (ε′ ∼ 590 at 1 kHz). The behavior of AC conductivity (σac) of the nanocomposite films indicated correlated barrier hopping type of conduction mechanism. The Cole–Davidson dielectric response becomes evident as the interfacial polarization process acquires a more symmetric form, tending to Debye relaxation. High value of ε′ promises direct application in capacitors. Moreover, the novel feature of destroying the percolative behavior by AuNPs may be applied even in other systems. 相似文献
53.
Ratiometric Interactions of Anionic Surfactants with Calf Thymus DNA Bound Cationic Surfactants: Study II 下载免费PDF全文
Tandrima Chaudhuri Animesh Pan Suman Das Satya Priya Moulik 《Journal of surfactants and detergents》2018,21(1):127-137
Cationic surfactant cetyltrimethylammonium bromide (CTAB) and cetylpyridinium bromide (CPB) bind to the calf thymus DNA (ct‐DNA) like anionic biopolymers electrostatically, and establish equilibrium in aqueous medium at pH 7. At low concentration, ct‐DNA does not interact with anionic surfactants, sodium dodecylsulfate (SDS) and sodium dodecylbenzylsulfonate (SDBS). However, in the ground state, anionic surfactant is found to clearly establish equilibrium with ct‐DNA‐bound cationic surfactant whereby the same surfactant–DNA isosbestic point reappears. We herein report a detail ratiometric binding of CPB with ct‐DNA, and interaction of anionic SDBS with DNA‐bound CPB in comparison with the combined ct‐DNA–CTAB–SDS system. Compaction of ct‐DNA in presence of CPB and its decompaction using anionic SDBS is also studied in comparison with CTAB–SDS combination. The techniques used are tensiometry, spectrophotometry, viscometry, cyclic voltammetry, circular dichroism, isothermal titration calorimetry, and density functional theory (DFT)‐based computational calculations. The size and surface charge density of the surfactant headgroups and the phosphate group in DNA have a contributing role in the DNA compaction–decompaction phenomenon. 相似文献
54.
Banani Ray Chowdhury Runu Chakraborty Utpal Ray Chaudhuri 《Journal of food engineering》2007,80(4):1171-1175
Data for the cell growth of Pediococcus acidilactici H during the fermentative production of bacteriocin, pediocin AcH (taken from a previous study) was modeled by two sigmoidal functions, modified Gompertz and Logistic. Results showed that the models could adequately account for the cell growth up to the growth phase, but failed to account for the stationary and death phase. 相似文献
55.
This paper describes the fabrication, experimentation and simulation stages of converting a 165 l domestic electric refrigerator to a solar powered one. A conventional domestic refrigerator was chosen for this purpose and was redesigned by adding battery bank, inverter and transformer, and powered by solar photovoltaic (SPV) panels. Various performance tests were carried out to study the performance of the system. The coefficient of performance (COP) was observed to decrease with time from morning to afternoon and a maximum COP of 2.102 was observed at 7 AM. Simulations regarding economic feasibility of the system for the climatic conditions of Jaipur city (India) were also carried out using RETScreen 4. It was observed that the system can only be economically viable with carbon trading option taken into account, and an initial subsidy or a reduction in the component costs – mainly SPV panels and battery bank. 相似文献
56.
Shahabi C. Ghandeharizadeh S. Chaudhuri S. 《Knowledge and Data Engineering, IEEE Transactions on》2002,14(2):447-455
In multiuser multimedia information systems (e.g., movie-on-demand, digital-editing), scheduling the retrievals of continuous media objects becomes a challenging task. This is because of both intra and inter lobject time dependencies. Intraobject time dependency refers to the real-time display requirement of a continuous media object. Interobject time dependency is the temporal relationships defined among multiple continuous media objects. In order to compose tailored multimedia presentations, a user might define complex time dependencies among multiple continuous media objects with various lengths and display bandwidths. Scheduling the retrieval tasks corresponding to the components of such a presentation in order to respect both inter and intra task time dependencies is the focus of this study. To tackle this task scheduling problem (CRS), we start with a simpler scheduling problem (ARS) where there is no inter task time dependency (e.g., movie-on-demand). Next, we investigate an augmented version of ARS (termed ARS+) where requests reserve displays in advance (e.g., reservation-based movie-on-demand). Finally, we extend our techniques proposed for ARS and ARS+ to address the CRS problem. We also provide formal definition of these scheduling problems and proof of their NP-hardness 相似文献
57.
The role of nitric oxide (NO) in the pathophysiology of gram-positive sepsis is uncertain. In inflammatory conditions, high-output NO production is catalyzed by the enzyme inducible nitric oxide synthase (iNOS). The ability of 2 strains of pneumococci, pneumococcal cell wall preparations, and purified pneumococcal capsule (Pnu-Imune 23) to trigger the production of iNOS protein and NO in RAW 264.7 murine macrophages was tested. Live pneumococci, oxacillin-killed pneumococci, and pneumococcal cell wall preparations stimulated the production of iNOS and NO by RAW 264.7 cells in the presence, but not the absence, of low concentrations of recombinant murine interferon-gamma. In contrast, purified pneumococcal capsule induced little or no iNOS or NO production by these cells. Thus, pneumococci stimulate high-output NO production by murine macrophages. The potential role of NO in the pathogenesis of pneumococcal sepsis deserves further study. 相似文献
58.
59.
BR Moed BK Ahmad JG Craig GP Jacobson MJ Anders 《Canadian Metallurgical Quarterly》1998,80(4):537-546
Cells of the innate immune system secrete cytokines early in immune responses that guide maturing T helper (Th) cells along appropriate lineages. This study investigates the role of cytokine networks, bridging the innate and acquired immune systems, in the pathogenesis of an organ specific autoimmune disease. Experimental allergic encephalomyelitis (EAE), a demyelinating disease of the central nervous system, is widely used as an animal model for multiple sclerosis. We demonstrate that interleukin (IL)-12 is essential for the generation of the autoreactive Th1 cells that induce EAE, both in the presence and absence of interferon gamma. The disease-promoting effects of IL-12 are antagonized by IL-10 produced by an antigen nonspecific CD4+ T cell which, in turn, is regulated by the endogenous production of IL-12. This unique immunoregulatory circuit appears to play a critical role in controlling Th cell differentiation and provides a mechanism by which microbial triggers of the innate immune system can modulate autoimmune disease. 相似文献
60.
The present study tested the hypothesis that one or more tyrosine kinase(s) are downstream of protein kinase C (PKC) in the signal transduction pathway responsible for the cardioprotective effect of ischemic preconditioning (PC). Isolated rabbit hearts were subjected to 30 min of regional ischemia followed by 2 h of reperfusion. Infarct size was measured by triphenyltetrazolium staining and expressed as a percentage of the area at risk. Infarction in control hearts was 32.9+/-1.8%. Ischemic PC with 5-min ischemia/10-min reperfusion reduced infarct size to 11.5+/-1.5% (P<0.05). Infusion of the tyrosine kinase inhibitors, genistein (50 microM) or lavendustin A (0.5 microM), alone did not affect the level of infarction. When infused around the 5-min PC ischemia genistein failed to block protection (13.7+/-1.0%). However, when present at the onset of the 30-min ischemia both genistein and lavendustin A completely aborted protection (31.4+/-2.0 and 28.1+/-1.5%, respectively). Activation of PKC by phorbol 12-myristate 13-acetate (PMA, 0.05 nmol) was as protective is ischemic PC (14.9+/-3.0%; P<0. 05). Similar to PC, PMA-induced protection was completely prevented by both genistein and lavendustin A. Conversely, anisomycin (50 ng/ml), an activator of MAP kinase kinases (dual tyrosine and threonine kinases), was very protective (7.5+/-1.6%; P<0.05) and this protection was still present when PKC was inhibited by 5 microM chelerythrine (12.1+/-1.6%; P<0.05). In conclusion, activation of a tyrosine kinase during the long ischemia appears to be required for cardioprotection in the rabbit heart. Furthermore, the ability of tyrosine kinase inhibitors to block PMA-induced protection in conjunction with the failure of PKC inhibition to prevent anisomycin-induced protection suggests that the tyrosine kinase is downstream of PKC and that the tyrosine kinase may be a MAP kinase kinase. 相似文献