Anti-melanoma, tyrosinase inhibitory and anti-microbial activities of gold nanoparticles synthesized from aqueous leaf extracts of Teraxacum officinale

There has been a tenacious search for pharmaceuticals of natural origin, as they are cost-effective and are noted for having little or no side effects. The rate at which diseases are developing resistance to synthetic drugs is quite alarming, and the side effects of these drugs remain an excruciating agony to the pharmaceutical industry. Gold nanoparticles (AuNPs) have wide applications in current technology. However, their use in medicine has not been adequately explored. Chemical methods for the synthesis are associated with environmental benignity and tissue toxicity on in vivo administration. For the first time, we have synthesized AuNPs from leaf extracts of Teraxacum officinale that were found to have significant anti-melanoma, tyrosinase inhibitory and anti-microbial effects, and hence stand as promising candidates for use in cosmetics medical and food industries.     

Red yeast barley reduces plasma glucose levels and activates AMPK phosphorylation in <Emphasis Type=Italic>db/db</Emphasis> mice

Red yeast (Monascus purpureus) fermented over rice has a limited hypoglycemic activity. To enhance its glucose-lowering effect, we fermented red yeast over waxy barley, a hypoglycemic grain with high levels of fibers and β-glucans, and investigated the metabolic effects of red yeast barley (RYB) in high-fat-fed hyperglycemic db/db mice for 6 weeks. The fasting glucose levels were significantly reduced in the RYB group at 6 weeks by 25% (p<0.05), as was the glucose tolerance (−27% of area under the curve in RYB vs. controls, p<0.05). Plasma insulin levels and the expression of PPAR-γ were unaltered, however, the phosphorylation activation of hepatic AMP-activated protein kinase (AMPK) was increased significantly in RYB group compared with controls suggesting that hypoglycemic effect of RYB may be achieved by AMPK-dependent mechanism. RYB may be used as a hypoglycemic functional food modulating cellular AMPK activity.     

Application of real/mixed μ computational techniques to an H∞ missile autopilot

A multivariable missile autopilot is synthesized using an H_∞ approach. A tradeoff is achieved between performance, actuators solicitation and uncertainties in the actuators and bending modes dynamics. Robust stability and performance of the control law are then studied in the face of large real parametric aerodynamic uncertainties: computational techniques for real and mixed μ analysis (namely De Gaston and Safonov's, Dailey's, Jones’, Young and Doyle's, Fan, Tits and Doyle's and Safonov and Lee's methods) are briefly reviewed before being used to compute either the exact value, or an interval of the structured singular value (SSV). For small amounts of parameters, the upper and lower bounds provided by these methods are compared to the exact value, computed by De Gaston and Safonov's method. For larger amounts of parameters, NP hardness of the problem prohibits the use of algorithms which compute the exact value: these algorithms are indeed necessarily exponential-time. As an alternative in this case, the use of polynomial-time methods for computing upper and lower bounds leads in our examples to accurate approximates of the real and mixed structured singular values.     

Activatable Peptides for Rapid and Simple Visualization of Protease Activity Secreted in Living Cells

Activity-based monitoring of cell-secreted proteases has gained significant interest due to the implication of these substances in diverse cellular functions. Here, we demonstrated a cell-based method of monitoring protease activity using fluorescent cell-permeable peptides. The activatable peptide consists of anionic (EEEE), cleavable, and cationic sequences (RRRR) that enable intracellular delivery by matrix metalloproteinase-2 (MMP2), which is secreted by living cancer cells. Compared to HT-29 cells (MMP2-negative), HT-1080 cells (MMP2-positive) showed a strong fluorescence response to the short fluorescent peptide via cell-secreted protease activation. Our approach is expected to find applications for the rapid visualization of protease activity in living cells.     

On the secrecy outage probability and performance trade-off of the multi-hop cognitive relay networks

Telecommunication Systems - We study the physical-layer security of multi-hop secondary network under spectrum sharing constraint caused by the primary, which consists of many simultaneously...     

Novel Components of the Sex Pheromones Produced by Emerald Moths: Identification,Synthesis, and Field Evaluation

The subfamily Geometrinae (Lepidoptera: Geometridae) includes many species called emerald moths. Based on our recent finding of novel polyenyl compounds, including a double bond at the 12-position from two geometrine species, Hemithea tritonaria and Thalassodes immissaria intaminata, (6Z,9Z,12Z)-6,9,12-trienes and (3Z,6Z,9Z,12Z)-3,6,9,12-tetraenes with a C₁₇–C₂₀ straight chain were synthesized and analyzed by GC-MS. The 6,9,12-trienes, which were prepared by a double Wittig reaction between two alkanals and an ylide derived from (Z)-1,6-diiodo-3-hexene, characteristically produced fragment ions at m/z 79, 150, and M–98. The 3,6,9,12-tetraenes, which were prepared by a coupling between (Z)-3-alkenal and an ylide derived from (3Z,6Z)-1-iodo-3,6-nonadiene, showed fragment ions at m/z 79, 148, and M–96. These diagnostic ions were useful to distinguish these compounds from other known polyenyl pheromones, such as 4,6,9- and 6,9,11-trienes and 1,3,6,9-tetraenes. With reference to the GC-MS data, pheromone extracts of other species in Geometrinae inhabiting the Iriomote Islands were analyzed, and the 6,9,12-trienes were identified in the pheromone gland extracts of Pamphlebia rubrolimbraria rubrolimbraria and Maxates versicauda microptera. Furthermore, a field evaluation of the synthetic polyenes in a mixed forest of Tokyo revealed the following new male attractants for emerald moths: Idiochlora ussuriaria by a C₁₇ 6,9,12-triene and Jodis lactearia by a C₂₀ 3,6,9,12-tetraene, indicating the characteristic chemical structures of Geometrinae pheromones. On the other hand, through reexamination of the pheromone extract of H. tritonaria, (3E,6E)-α-farnesene was identified as an electrophysiologically active component in addition to the C₁₇ 6,9,12-triene. The binary mixture attracted more males than the single component lure baited with the triene in the Iriomote Islands.     

Disruption of ergosterol biosynthesis,growth, and the morphological transition in <Emphasis Type="Italic">Candida albicans</Emphasis> by sterol methyltransferase inhibitors containing sulfur at C-25 in the sterol side chain

The sterol substrate analog 25-thialanosterol and its corresponding sulfonium salt were evaluated for their ability to serve as antifungal agents and to inhibit sterol methyltransferase (SMT) activity in Candida albicans. Both compounds inhibited cell proliferation, were fungistatic, interrupted the yeastlike-form to germ-tube-form transition, and resulted in the accumulation of zymosterol and related Δ²⁴-sterols concurrent with a decrease in ergosterol, as was expected for the specific inhibition of SMT activity. Feedback on sterol synthesis was evidenced by elevated levels of cellular sterols in treated vs. control cultures. However, neither farnesol nor squalene accumulated in significant amounts in treated cultures, suggesting that carbon flux is channeled from the isoprenoid pathway to the sterol pathway with minor interruption or redirection until blockage at the C-methylation step. Activity assays using solubilized C. albicans SMT confirmed the inhibitors impair SMT action. Kinetic analysis indicated that 25-thialanosterol inhibited SMT with the properties of a time-dependent mechanismbased inactivator K _i of 5 =gmM and apparent k _inact of 0.013 min⁻¹, whereas the corresponding sulfonium salt was a reversible-type transition state analog exhibiting a K _i of 20 nM. The results are interpreted to imply changes in ergosterol homeostasis as influenced by SMT activity can control growth and the morphological transition in C. albicans, possibly affecting disease development.     

Influence of some vegetable oils on the photocrosslinking of coatings based on an o-cresol novolac epoxy resin and a bis-cycloaliphatic diepoxide

The influence of cashew nut shell oil (CNO), epoxidized soybean oil (ESO), castor oil (CO), and dioctyl phtalate (DOP) on the photocrosslinking kinetics of UV curable mixtures containing an o-cresol novolac epoxy resin (CNE), a bis-cycloaliphatic diepoxide monomer (BCDE), and a triarylsulfonium salt (TAS) as a cationic photoinitiator has been studied. The formulation with a weight ratio CNE/BCDE/TAS of 60/40/5 was found to have the highest cure rate and the greatest final conversion of epoxy groups upon UV exposure. The presence of an unsaturated oil or of DOP in the UV curable formulation, at a content ranging from 0.07 to 0.79 mol/kg, was shown to increase the initial polymerization rate of the epoxy groups from 12 up to 31 mol/kg s, and the epoxy conversion after 18 s UV exposure from 80 up to 95%. It was found that the UV cured coatings containing CNO or DOP at concentrations between 0.3 and 0.6 mol/kg and ESO at concentrations between 0.12 and 0.19 mol/kg exhibit the best performance. These results were explained by a number of competitive factors, mainly the effects of the chemical structure and content of the oils and of DOP on the polarity, viscosity, compatibility, and internal filter effect of the UV curable resins, as well as by the characteristics of the tridimensional polymer networks formed upon UV exposure. The materials produced under the optimal conditions determined in this study can be used as high performance decorative and protective coatings and also as adhesives in different sectors of applications.