Cryptanalysis and Security Enhancement of an Advanced Authentication Scheme using Smart Cards, and a Key Agreement Scheme for Two-Party Communication

In this work we consider two protocols for performing cryptanalysis and security enhancement. The first one by Song, is a password authentication scheme based on smart cards. We note that this scheme has already been shown vulnerable to the off-line password guessing attack by Tapiador et al. We perform a further cryptanalysis on this protocol and observe that it is prone to the clogging attack, a kind of denial of service (DOS) attack. We observe that all smart card based authentication protocols which precede the one by Song, and require the server to compute the computationally intensive modular exponentiation, like the one by Xu et al., or Lee at al., are prone to the clogging attack. We then suggest an improvement on the protocol to prevent the clogging attack. The other protocol we consider is a two-party identity-based authenticated key agreement protocol by Hölbl et al. They have devised two such protocols in their work. They call them Protocol 1 and Protocol 2. Both the protocols have already been shown vulnerable to the insider attack in a recent work by Chen et al. Here we consider Protocol 2 and show its vulnerability to a simple man-in-the-middle attack where the adversary does not know or calculate either party\u27s private key, or the session key. Protocol 2 by Hölbl et al is an improvement over a previous work by Tseng. This makes the Tseng\u27s protocol vulnerable to the attack we illustrate. We further suggest an additional step for these protocols to make them immune against the man-in-the-middle attack

A Second Generation 2-Methoxyestradiol Prodrug Is Effective Against Barrett's Adenocarcinoma in a Mouse Xenograft Model

This is the author's accepted manuscript. The original is available at http://mct.aacrjournals.org/content/12/3/2552-Methoxyestradiol (2-ME2) is an endogenous metabolite of estradiol. In preclinical models, 2-ME2 is effective against different types of tumors. Unfortunately, only low systemic concentrations of 2-ME2 can be achieved following oral administration, even after very high doses are administered to patients. In an effort to solve this problem we have now synthesized and tested a new prodrug of 2-ME2 that is water soluble due to a bio-reversible hydrophilic group added at the 3-position and more effectively resists metabolic inactivation due to an ester moiety added to mask the 17-position alcohol. We are reporting here for the first time that this double prodrug of 2-ME2 is effective as an antiproliferative and anti-cancer agent for both in vitro and in vivo studies against Barrett's esophageal adenocarcinoma (BEAC), and provided greater potency than 2-ME2 in inhibiting the growth of BEAC xenografts. Finally, studies indicate that, like 2-ME2, the 2-ME2-PD1 exhibits anticancer effect through possible disruption of microtubule-network

The Drosophila Anion Exchanger (DAE) lacks a detectable interaction with the spectrin cytoskeleton

<p>Abstract</p> <p>Background</p> <p>Current models suggest that the spectrin cytoskeleton stabilizes interacting ion transport proteins at the plasma membrane. The human erythrocyte anion exchanger (AE1) was the first membrane transport protein found to be associated with the spectrin cytoskeleton. Here we evaluated a conserved anion exchanger from Drosophila (DAE) as a marker for studies of the downstream effects of spectrin cytoskeleton mutations.</p> <p>Results</p> <p>Sequence comparisons established that DAE belongs to the SLC4A1-3 subfamily of anion exchangers that includes human AE1. Striking sequence conservation was observed in the C-terminal membrane transport domain and parts of the N-terminal cytoplasmic domain, but not in the proposed ankyrin-binding site. Using an antibody raised against DAE and a recombinant transgene expressed in <it>Drosophila </it>S2 cells DAE was shown to be a 136 kd plasma membrane protein. A major site of expression was found in the stomach acid-secreting region of the larval midgut. DAE codistributed with an infolded subcompartment of the basal plasma membrane of interstitial cells. However, spectrin did not codistribute with DAE at this site or in anterior midgut cells that abundantly expressed both spectrin and DAE. Ubiquitous knockdown of DAE with dsRNA eliminated antibody staining and was lethal, indicating that DAE is an essential gene product in <it>Drosophila</it>.</p> <p>Conclusions</p> <p>Based on the lack of colocalization and the lack of sequence conservation at the ankyrin-binding site, it appears that the well-characterized interaction between AE1 and the spectrin cytoskeleton in erythrocytes is not conserved in <it>Drosophila</it>. The results establish a pattern in which most of the known interactions between the spectrin cytoskeleton and the plasma membrane in mammals do not appear to be conserved in <it>Drosophila</it>.</p

Photoinduced hole-transfer in nanoparticle-dye hybrid composites: a route for exciton dissociation leading to photovoltaic devices

We present a hybrid nanocomposite system based on lead sulfide (PbS) quantum dots and a metal phthalocyanine derivative for photovoltaic devices. The composite has been chosen in such a manner that photoinduced hole-transfer from the quantum dot to the dye is energetically favorable. Photoluminescence of PbS nanoparticles quenched upon PbS:dye composite formation substantiating that such a hole-transfer occurred leading to dissociation of photogenerated excitons. The devices based on the PbS:phthalocyanine systems sandwiched between two electrodes have yielded photovoltaic characteristics. Short-circuit current of the devices has increased with an increase in concentration of the dye in hybrid nanocomposites. Since the devices are based on PbS quantum dots, they moreover have acted as NIR-active solar cells

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Not AvailableConservation agriculture (CA)-based practices have been promoted and recouped, as they hold the potential to enhance farm profits besides a consistent improvement in soil properties. A 7 years’ field experiment consisting of three crop establishment practices viz., zero-till flatbed (ZTFB), permanent beds (PNB), conventional system (CT) along with the three-nutrient management; nutrient expertbased application (NE), recommended fertilization (RDF), and farmers’ fertilizer practice (FFP), was carried out from 2013 to 2020. The CA-based practices (ZTFB/PNB) produced 13.9–17.6% greater maize grain-equivalent yield (MGEY) compared to the CT, while NE and RDF had 10.7–20% greater MGEY than the FFP. PNB and ZTFB gave 28.8% and 24% additional net returns than CT, while NE and RDF had 22.8% and 17.4% greater returns, respectively over FFP. PNB and ZTFB had 2.3–4.1% (0.0–0.20 m soil layers) lower bulk density than the CT. Furthermore, microbial biomass carbon (MBC) increased by 8–19% (0.0–0.50 m soil layers) in ZTFB/PNB over the CT, and by 7.6–11.0% in NE/RDF over FFP. Hence, CA-based crop establishment coupled with the NE or RDF could enhance the yields, farm profits, soil properties of the maize–chickpea rotation, thereby, could sustain production in the long run.Not Availabl