On the security of the Yen-Guo's domino signal encryption algorithm (DSEA)

Recently, a new domino signal encryption algorithm (DSEA) was proposed for digital signal transmission, especially for digital images and videos. This paper analyzes the security of DSEA, and points out the following weaknesses: 1) its security against the brute-force attack was overestimated; 2) it is not sufficiently secure against ciphertext-only attacks, and only one ciphertext is enough to get some information about the plaintext and to break the value of a sub-key; 3) it is insecure against known/chosen-plaintext attacks, in the sense that the secret key can be recovered from a number of continuous bytes of only one known/chosen plaintext and the corresponding ciphertext. Experimental results are given to show the performance of the proposed attacks, and some countermeasures are discussed to improve DSEA.Comment: 11 pages, 5 figure

Low Cost Spacelift to LEO, GTO, and Beyond using the OSP-2 Peacekeeper Space Launch Vehicle

The Peacekeeper (PK) Space Launch Vehicle (SLV) is a new launch vehicle for providing cost effective spacelift for small-to-medium, Government-sponsored spacecraft, including addressing an emerging need of small Geosynchronous (GEO) spacecraft. This vehicle is being developed by Orbital Sciences under the Orbital Suborbital Program 2 (OSP-2) contract with the United States Air Force (USAF) Space and Missile Systems Center (SMC) Detachment 12 Rocket System Launch Program (RSLP). Preliminary designs and capabilities were presented at the 2003 Small Satellite Conference. In the year since, there has been significant interest in the PK SLV, and the first missions have been initiated with an anticipated first launch in 2007. In addition to the baseline LEO and MEO orbital missions, a burgeoning interest has been revealed in using a PK SLV derivative to deliver small spacecraft to high energy orbits, such as geosynchronous transfer orbits (GTO) and beyond, including potential lunar missions. This Peacekeeper Space Lift Vehicle (PK SLV) follows in the heritage of RSLP and Orbital’s Minotaur SLV, merging advanced commercial launch vehicle technology with surplus Air Force boosters to provide a low cost, low risk spacelift capability to US-Government sponsored spacecraft. The baseline PK SLV uses the first three Peacekeeper solid-rocket stages in unmodified form, along with the same Orion 38 Stage 4 insertion motor as Pegasus, Taurus, and Minotaur. The avionics design is shared with the other OSP-2 vehicles, including the Minotaur SLV. It also uses the 92 inch payload fairing that was developed and flown for Orbital’s Taurus SLV. This combination of common, flight proven avionics and subsystems, along with existing ICBM motors results in a new vehicle that has a very low risk and low cost development. This paper presents the status and capabilities of this baseline PK SLV system. More significantly, it will cover the development of the enhanced evolution that addresses the development of the capability for delivering relatively small spacecraft to GTO and other high energy orbits. To maximize performance to these high orbits, different upper stage motors have been evaluated and the mechanical design mass optimize

VR Hackfest

We built the future of the web — today! Our four-person eLibrary team designed an afternoon workshop and corresponding network-connected public exhibit centered around two cutting-edge internet technologies: IPFS and A-Frame

Isolation and Identification of Acholeplasma sp. from the Mud Crab, Scylla serrata

For the first time, a mollicute-like organism (MLO) was cultured from moribund mud crabs (Scylla serrata) during an outbreak of clearwater disease in Zhejiang Province, China. The MLO displayed a fried-egg colony morphology in culture, did not possess a cell wall, and was not retained by 0.45 μm and 0.2 μm filters. It was able to ferment glucose, sucrose, lactose, and maltose, but it did not utilize arginine and urea. The MLO grew in the absence of bovine serum and was not susceptible to digitonin. Sequence analysis of the 16S rRNA gene revealed that this MLO had 99% identity with Acholeplasma laidlawii PG-8A, which indicates that the organism isolated from mud crabs is a member of the genus Acholeplasma

Icariin stimulates differentiation of bone marrow-derived mesenchymal stem cells (BM-MSCs) through activation of cAMP/PKA/CREB

Icariin, a prenylated flavonol glycoside isolated from Epimedium, has been considered as a potential alternative therapy for osteoporosis. The present study aimed to clarify the detailed molecular mechanisms of action of icariin on osteoblast function, using bone marrow-derived mesenchymal stem cells (BM‑MSCs). BM-MSCs were first stimulated by icariin. Then, gene and protein expression of cAMP/ PKA/CREB signaling molecules were analyzed by RT-PCR and western blotting (WB), and alkaline phosphatase (ALP) was analyzed in cell lysates by ELISA. MTT assays indicated that icariin did not have significant effects on cell viability up to 1 μM. Icariin showed a dose-dependent effect on the alkaline phosphatase activity of BM-MSCs. WB analysis showed that icariin treatment of BM-MSCs significantly enhanced the protein expression of protein kinase A (PKA) and cAMP-responsive element binding protein (CREB), while RT-PCR results showed that icariin dose-dependently increased the mRNA levels of PKA and CREB. Icariin induced BM-MSC differentiation by BMP2, Smad1, and Runx2. RT‑PCR and WB results indicated that icariin significantly increased the expression of BMP2, Smad1, and Runx2 in BM‑MSCs. These results suggest that icariin is an agonist of the cAMP/PKA/CREB pathway in BM-MSC differentiation, raising the possibility that it could be used in the treatment of osteoporosis