Maximizing the Efficiency using Montgomery Multipliers on FPGA in RSA Cryptography for Wireless Sensor Networks

The architecture and modeling of RSA public key encryption/decryption systems are presented in this work. Two different architectures are proposed, mMMM42 (modified Montgomery Modular Multiplier 4 to 2 Carry Save Architecture) and RSACIPHER128 to check the suitability for implementation in Wireless Sensor Nodes to utilize the same in Wireless Sensor Networks. It can easily be fitting into systems that require different levels of security by changing the key size. The processing time is increased and space utilization is reduced in FPGA due to its reusability. VHDL code is synthesized and simulated using Xilinx-ISE for both the architectures. Architectures are compared in terms of area and time. It is verified that this architecture support for a key size of 128bits. The implementation of RSA encryption/decryption algorithm on FPGA using 128 bits data and key size with RSACIPHER128 gives good result with 50% less utilization of hardware. This design is also implemented for ASIC using Mentor Graphics

Progesterone Signaling Mechanisms in Brain and Behavior

Steroid hormone, progesterone, modulates neuroendocrine functions in the central nervous system resulting in alterations in physiology and behavior. These neuronal effects are mediated primarily by intracellular progestin receptors (PRs) in the steroid-sensitive neurons, resulting in transcription-dependent genomic actions (classical mechanism). In addition to progesterone, intracellular PRs can also be activated in a “ligand-independent” manner by neurotransmitters, peptide growth factors, cyclic nucleotides, and neurosteroids. Recent studies indicate that rapid, non-classical progesterone actions involving cytoplasmic kinase signaling and/or extranuclear PRs can result in both transcription-independent and transcription-dependent actions. Cross-talk between extranuclear and classical intracellular signaling pathways promotes progesterone-dependent behavior in mammals. This review focuses on the mechanisms by which progesterone-initiated signaling mechanisms converge with PRs in the brain to modulate reproductive behavior in female rodents

Protein synthesis in Mycobacterium tuberculosis H37Rv and the effect of streptomycin in Streptomycin-Susceptible and -resistant Strains

An efficient in vitro amino acid-incorporating system from Mycobacterium tuberculosis H37Rv was standardized. Ribonucleic acid (RNA) isolated from phage-infected M. smegmatis cells served as natural messenger RNA and directed the incorporation of 14C-amino acids into protein. The effects of various antitubercular drugs and "known inhibitors" of protein synthesis on amino acid incorporation were studied. Antibiotics like chloramphenicol and tetracycline inhibited mycobacterial protein synthesis, though they failed to prevent the growth of the organism. This failure was shown to be due to the impermeability of mycobacteria to these drugs by use of "membrane-active" agents along with the antibiotics in growth inhibition studies. Several independent streptomycin-resistant mutants of M. tuberculosis H37Rv were isolated. Streptomycin inhibited the incorporation of 14C-amino acids into proteins by whole cells of a streptomycin-susceptible strain by more than 90%, whereas very little or no inhibition was observed in either high-level or low-level streptomycin-resistant strains. In vitro, streptomycin was an effective inhibitor of susceptible strains, whereas in streptomycin-resistant strains the concentration of streptomycin at which half-maximal inhibition was produced varied according to the resistance of whole cells, and there was a correlation between the two. In one low-level streptomycin-resistant mutant, the in vitro amino acid-incorporating system was as sensitive to various concentrations of streptomycin as the parental type, and a possible involvement of a membrane site in the development of low-level resistance was indicated. Streptomycin susceptibility and high-level resistance were shown to be ribosomal in nature

Effect of phytohormones on nuclear RNA synthesis in germinating seeds of Trigonella foenumgraeceum and its callus

Treatment of Trigonella foenumgraeceum (fenugreek) seedlings with naphthalene acetic acid plus gibberellic acid enhanced the RNA synthesising capacity of nuclei isolated from the hypocotyl and cotyledonary regions. This increase was more pronounced in the nuclei from the hypocotyl region than from the cotyledonary region. In vitro addition of these phytohormones did not stimulate RNA synthesis by nuclei. The RNA synthesis by mitochondria was not affected by preincubating the seedlings with the hormones. The nuclei isolated from callus cultures of fenugreek hypocotyl treated with the hormone also showed increased RNA synthesis

Chromatinized templates reveal the requirement for the LEDGF/p75 PWWP domain during HIV-1 integration in vitro

Integration is an essential step in the retroviral lifecycle, and the lentiviral integrase binding protein lens epithelium-derived growth factor (LEDGF)/p75 plays a crucial role during human immunodeficiency virus type 1 (HIV-1) cDNA integration. In vitro, LEDGF/p75 stimulates HIV-1 integrase activity into naked target DNAs. Here, we demonstrate that this chromatin-associated protein also stimulates HIV-1 integration into reconstituted polynucleosome templates. Activation of integration depended on the LEDGF/p75-integrase interaction with either type of template. A differential requirement for the dominant DNA and chromatin-binding elements of LEDGF/p75 was however observed when using naked DNA versus polynucleosomes. With naked DNA, the complete removal of these N-terminal elements was required to abate cofactor function. With polynucleosomes, activation mainly depended on the PWWP domain, and to a lesser extent on nearby AT-hook DNA-binding motifs. GST pull-down assays furthermore revealed a role for the PWWP domain in binding to nucleosomes. These results are completely consistent with recent ex vivo studies that characterized the PWWP and integrase-binding domains of LEDGF/p75 as crucial for restoring HIV-1 infection to LEDGF-depleted cells. Our studies therefore establish novel in vitro conditions, highlighting chromatinized DNA as target acceptor templates, for physiologically relevant studies of LEDGF/p75 in lentiviral cDNA integration

RNA polymerase activity in isolated nuclei of Nicotiana sanderae callus: characteristics and modulation during differentiation

Isolated nuclei from differentiating cultures of Nicotiana sanderae showed increased levels of RNA polymerase activity as compared to the nuclei from callus cultures. The RNA synthetic activity was dependent on nucleotide triphosphates and Mg2+ and was destroyed by RNase. Maximum activity was obtained in the presence of 50 mM (NH4)2 SO4 and α-amanitin inhibited 40% and 55% of the activity in the nuclei from callus and differentiating tissue respectively. The nuclei from differentiating tissue elicited a 3-fold increase in RNA polymerase I and a 4-fold augmentation in RNA polymerase II activities

Efficient Retransmission QoS-Aware MAC Scheme in Wireless Sensor Networks

In this paper, an Efficient Retransmission Random Access Protocol (ERRAP) is designed that combines scheme of collision avoidance and energy management for low-cost, short-range wireless radios and low-energy sensor nodes applications. This protocol focuses on efficient Media Access Control (MAC) schemes to provide autonomous Quality of Service (QoS) to the sensor nodes in one-hop QoS retransmission group in WSNs where the source nodes do not have receiver circuits. These sensor nodes can only transmit data to a destination node, but cannot receive acknowledgement or control signals from the destination node. The proposed scheme ERRAP provides QoS to the nodes which work independently on predefined time by allowing them to transmit each packet an optimal number of times within a given period. Our simulation results demonstrate the superiority of ERRAP scheme which increases the delivery probability and reduces the energy consumption