Verifiable (t, n) Threshold Signature Scheme Based on Elliptic Curve

Based on tht difficulty of solving the ECDLP (elliptic curve discretelogarithm problem) on the finite field, we present a (t, n) threshold signature scheme and averifiable key agreement scheme without trusted party. Applying a modified elliptic curve signatureequation, we gel a more efficient signature scheme than the existing ECDSA (elliptic curve digitalsignature algorithm) from the computability and security view. Our scheme has a shorter key, fastercomputation, and better security.

Relationship Between Changes in Leaf Endogenous Hormone Contents and Senescence During Grain Filling Stage of a Rice Hybrid and its Parents

A major problem in hybrid rice production is the occurrence of leaf senescence during the grain filling stage that can result in reduction of yield. Changes in contents of several endogenous hormones are related to leaf senescence. The relationship between endogenous hormones and leaf senescence in the rice hybrid Tiyou 418 and its parents Tijin and C418, was undertaken for investigation. Indicators of leaf senescence, including superoxide dismutase (SOD) activity, malondialdehyde (MDA) accumulation and chlorophyll content, as well as the contents of abscisic acid (ABA), zeatin riboside (ZR), gibberellin (GA1/3) and auxin (IAA) in the leaves were determined. Different rates of leaf senescence were observed in the three materials. Senescence occurred earliest and fastest in Tijin, followed by Tiyou 418 and then C418. A similar trend was recorded in ABA, ZR, and IAA contents during the grain filling stage in the three materials. Changes in (GA1/3+ZR+IAA)/ABA ratios were also similar, being quite stable during the early stage of leaf senescence, and decreasing markedly during the late stage. The ratio declined more dramatically in Tijin, in accordance with its faster leaf senescence. The results suggest that the ratio of (GA1/3+ZR+IAA)/ABA regulates chlorophyll content, SOD activity, MDA content and membrane lipid peroxidation. It is postulated that endogenous hormones may play a role in the regulation of leaf senescence in a systematic way.

Blind MIMO Channel Estimation Based on Modulation-Induced Two-Cycle Cyclostationarity

In this paper, a novel approach is presented to the multiuser channelidentification . The approach makes use of the modulation-induced Cyclostationarity, capable ofidentifying individual channels of different users. By means of the decomposition of the cyclicspectrum method, the blind estimation of the channel can be achieved . The approach is rathersimple, with considerable advantages over existing techniques, and suitable for the multiuser uplink. The identifiabilily condition and its proof are also concluded in the paper. And finally the.simulation of identification algorithm is given.

Joint Semi-Blind Channel Estimation and Data Sequence Detection of OFDM Systems

In this paper, a joint semi blind channel estimation and data sequence detection of OFDM systems over the multipath frequency selective fading channels is proposed and investigated. The basic idea of the algorithm is to first use the correlation among adjacent subchannels in the frequency domain to estimate the channel's parameters with an AutoRegressive (AR) process based on the decision directed estimation principle, and then to search the ML solution using the Viterbi algorithm. The algorithm realizes on line channel estimation and data detection of OFDM signals without any periodic pilot signal and statistic information about the channels, so it is suited to high data rate transmission over slow fading channels in the coming generation mobile communication systems.

Apoptosis in human germinal centre B cells by means of CC chemokine receptor 3 expression induced by interleukin-2 and interleukin-4

Background CC chemokine receptor 3 (CCR3), expressed on some inflammatory cells, is a member of the chemokine receptor family. Its ligand is eotaxin/CCL11. In this research, we studied the expression and function of CCR3 induced by interleukin-2 (IL-2) and interleukin-4 (IL-4) on human germinal centre (GC) B cells.Methods Cells isolated from human tonsils were stimulated with IL-2 or/and IL-4 followed by bonding with eotaxin/CCL11. Flow cytometry was used to detect expression of CCR3 on GC B cells and apoptosis of GC B cells. Real time quantitative reverse transcription polymerase chain reaction and Northern blot assays were used to analyse the CCR3 mRNA expressed in the GC B cells. Chemotaxis and adhesion assays were used to determine the effect of eotaxin/CCL11 ligand bonded to CCR3 on GC B cells.Results There was no CCR3 expression on human freshly isolated GC B cells. The combination IL-2 and IL-4 could upregulate CCR3 mRNA and protein expression on GC B cells. Eotaxin could not induce GC B cell chemotaxis and adhesion but triggered apoptosis of GC B cells.Conclusion IL-2 and IL-4 together induced expression of CCR3 on GC B cells, and the receptor acted as a death receptor.