Gemini surfactants have important advantages, e.g., low micromolar CMCs and slow millisecond monomer ↔ micelle kinetics, for membrane mimetics and for delivering nucleic acids for gene therapy or RNA silencing. However, as a prerequisite, it is important to characterize interactions occurring between Gemini surfactants and proteins. Here NMR and CD spectroscopies are employed to investigate the interactions of cationic Gemini surfactants with RNase Sa, a negatively charged ribonuclease. We find that RNase Sa binds Gemini surfactant monomers and micelles at pH values above 4 to form aggregates. Below pH 4, where the protein is positively charged, these aggregates dissolve and interactions are undetectable. Thermal denaturation experiments show that surfactant lowers RNase Sa's conformational stability, suggesting that surfactant binds the protein's denatured state preferentially. Finally, Gemini surfactants were found to bind RNA, leading to the formation of large complexes. Interestingly, Gemini surfactant binding did not prevent RNase Sa from cleaving RNA.

Magnetite Fe3O4 nanoparticles (NPs) were prepared by chemical coprecipitation method. Silica-coated magnetite NPs were prepared by sol-gel reaction, subsequently coated with 3-aminopropyltriethoxysilane (APTES) via silanization reaction, and then were activated with 2,4,6-trichloro-1,3,5-triazine (TCT) and covalently immobilized with bovine serum albumin (BSA). The size and structure of the particles were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and dynamic light scattering (DLS) techniques. The immobilization was confirmed by Fourier transform infrared spectroscopy (FT-IR). XRD analysis showed that the binding process has not done any phase change to Fe3O4. The immobilization time for this process was 4 h and the amount of immobilized BSA for the initial value of 1.05 mg BSA was about 120 mg/gr nanoparticles. Also, the influences of three different buffer solutions and ionic strength on covalent immobilization were evaluated.

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Quantum digital signatures apply quantum mechanics to the problem of guaranteeing message integrity and nonrepudiation with information-theoretical security, which are complementary to the confidentiality realized by quantum key distribution. Previous experimental demonstrations have been limited to transmission distances of less than 5 km of optical fiber in a laboratory setting. Here we report the first demonstration of quantum digital signatures over installed optical fiber as well as the longest transmission link reported to date. This demonstration used a 90-km long differential phase shift quantum key distribution system to achieve approximately one signed bit per second -an increase in the signature generation rate of several orders of magnitude over previous optical fiber demonstrations. For many years, it was generally trusted that a simple handwritten signature was hard to forge and, therefore, could be taken as certification that the signatory was willing to be considered a source of the message and agreed with the contents. In addition, there was an acceptance that a signed message would be validated by a third party, which allowed complex transaction systems to operate with reasonable ease.The field of digital signatures seeks to restore some of the practical security aspects of handwritten signatures lost in the transition to digital communications. Digital signatures must guarantee no forging (that a message is signed by the legitimate sender and has not been modified), and non-repudiation (Alice cannot repudiate her message, that is, successfully deny that she sent it). Currently used digital signature schemes typically rely on "one-way" functions, which are computationally easy to evaluate in one direction but computationally difficult to invert without additional information. However, there is no existing proof of the long-term security of these signature schemes and they are vulnerable to algorithmic breakthroughs, emerging quantum data processing technologies and even significant large-scale investment in conventional computational technologies, -thus they only offer "computational security" against an attacker with currently accepted standards of reasonable computational resources.Naturally, there is strong motivation to develop digital signature schemes that offer "information-theoretical security", meaning that they are secure against all attackers, even those with unlimited computational resources Wegman-Carter message authentication offers information-theoretical security. However, to guarantee non-repudiation as well, one possibility is to use quantum digital signatures. QDS schemes operate using technology similar to that of QKD but employ protocols that do not require distillation of a fully secret key. Indeed, it is possible that both QKD and QDS schemes can work in parallel along the same optical fibers. This paper demonstrates the first implementation of QDS in an installed

The effects of osmotic stress induced by polyethylene glycol on the seed germination of 16 walnut genotypes (‘Z30’, ‘Z53’, ‘Z67’, ‘Z60’, ‘Z63’, ‘K72’, ‘B21’, ‘V30’, ‘Panegine20’, ‘Hartley’, ‘Pedro’, ‘Vina’, ‘Lara’, ‘Serr’, ‘Ronde de Montignac’, and ‘Chandler’) of Juglans regia L. were studied. Potted seeds were kept under controlled conditions (12/12-h light/dark photoperiod and 25 ± 1 °C) during the experiments. The objective was to screen genotypes and determine the critical range of osmotic potential (ψS) for walnut seeds during germination. Decreasing the ψS of the germination solutions markedly reduced germination percentage in all genotypes, but there were variations in degree among the genotypes. The Z genotypes were the most sensitive to osmotic stress, and their germination rates were the lowest at ψS more negative than –0.75 MPa. Cluster analysis produced a dendrogram with four groups differing in their tolerance to osmotic stress. Based on factor analysis, four factors explained 90.45% of data total variance. Factor analysis showed that tissue fresh and dry weight, tissue water content, and thickness were the most important traits under drought condition. Regression analysis failed to show a significant relationship between percent germination and either seed weight (r2 = 0.0601) or kernel weight (r2 = 0.0258).