Earticle

1,1-Bis(n-butyl)-2,3,4,5-tetraphenyl-1-silacyclopentadiene (3) and 1,1-bis(t-butyl)-2,3,4,5- tetraphenyl-1-silacyclopentadiene (4) are synthesized from the reaction of the versatile silole dianion (2) with n-butyl bromide and t-butyl bromide. Reduction of (3) and (4) with an excess of lithium to give 1,1-bis(n-butyl)-2,5-dilithio-2,3,4,5-tetraphenyl-1- silacyclopenta-3-enide (6) and 1,1-bis(t-butyl)-2,5-dilithio-2,3,4,5-tetraphenyl-1-silacyclopenta-3-enide (7). 13C-NMR study of two 2,5- carbodianions (6 and 7) shows tert-carbanion at 73.18 and 78.12 ppm respectively. Two bulky tert- butyl groups in (7) increase the inversion barrier at the tert-carbanion, line broadenings of tert-butyl groups in 1H and 13C-NMR spectrum are observed.

Bu3Sn-endded poly(vinyl)s with biological activity were obtained by the radical polymerization of vinyl monomers using thianthrene cation radical/nBu3H. Thianthrene cation and stannyl radicals promoted the homopolymerization and copolymerization of styrene and ethyl vinyl ether having number average molecular weights of 2000- 3100. Tributyltin hydride functions as a chain transfer agent. Such polymereization by cationic thianthrene and stannyl radicals could provide some clues for the biological reaction in living animals. Plausible polymerization mechanisms were suggested.

ZnO nanoparticles and vinyl pyridine were added to the mixture of MMA (methyl methacrylate), HEMA (2-hydroxy ethyl methacrylate) and NVP (N-vinylpyrrolidone) in a mould at various concentrations. Cross-linker EGDMA (ethyleneglycoldimethacrylate) and AIBN (azobisisobutyronitrile) initiator were finally added to the mixture and then heated at 80oC for 60 min to prepare high-performance hydrogel ophthalmic lens. The physical properties of the hydrogel ophthalmic material were investigated by measuring the average value of refractive index, water content and optical transmittance. The refractive index of 1.429~1.450, water content of 34~41%, and visible transmittance of 78~90% were obtained. The material is possibly used to manufacture UV-block hydrogel contact lens.

This paper describes a method for the preparation of porous polymethylmethacrylate showing optical reflectivity from the porous silicon template. A porous polymethylmethacrylate showing optical reflectivity was prepared by replicating porous silicon template which was obtained by applying a computer-generated periodic square current density and resulted in a mirror with high reflectivity in a specific narrow spectral region. A porous polymethylmethacrylate showing an excellent reflectivity was successfully obtained by dissolving the Porous silicon template from the porous polymethylmethacrylate composite film. A porous polymethylmethacrylate exhibited a sharp reflection resonance in the reflectivity spectrum. Surface image of the porous polymethylmethacrylate indicated that the surface of the porous polymethylmethacrylate film had a porous structure. These porous polymethylmethacrylate films in aqueous solutions were stable for several days without any degradation.

Polymerization of monomeric amyloid-β peptides (Aβ) into soluble oligomers and insoluble fibrils is one of the major pathways triggering the pathogenesis of Alzheimer’s disease (AD). Using small molecules to prevent the polymerization of Aβ peptides can, therefore, be an effective therapeutic strategy for AD. In this study, we investigated the effects of mono- and bi-flavonoids on Aβ42 toxicity and fibrillogenesis and found that the bi-flavonoid, taiwaniaflavone (TF) effectively and specifically inhibits Aβ toxicity and fibrillogenesis. Compared to TF, the mono-flavonoid apigenin (AP) is less effective and less specific. Our data showed that differential effects of the mono- and bi- flavonoids on Aβ fibrillogenesis correlate with their varying cytoprotective efficacies. We also found that other bi- flavonoids, namely 2',8''- biapigenin, amentoflavone, and sumaflavone, can also effectively inhibit Aβ toxicity and fibrillogenesis, implying that the participation of two mono-flavonoids in a single bi-flavonoid molecule enhanced their activity. Bi- flavonoids, while strongly inhibited Aβ fibrillogenesis, accumulated nontoxic Aβ oligomeric structures, suggesting that these are offpathway- oligomers. Moreover, TF abrogated the toxicity of preformed Aβ oligomers and fibrils, indicating that TF and other bi-flavonoids may also reduce the toxicity of toxic Aβ species. Altogether, our data clearly show that bi-flavonoids, possibly due to the possession of two Aβ binders separated by an appropriate size linker, are likely to be promising therapeutics to suppress Aβ toxicity.

Using computational approaches we can dock small molecules into the structures of Macromolecular targets and then score their potential complementarity to binding sites is widely used in hit identification and lead optimization techniques. This review seeks to provide the application of docking in structure-based drug design (binding mode prediction, Lead Identification and Lead optimization), and also discussed how to manage errors in docking methodology in order to overcome certain limitations of docking and scoring algorithm.

1-Aza-12-crown-4 macrocyclic ligand was combined with styrene (2th petroleum in 4th class hazardous materials) divinylbenzene copolymer having 1%, 2%, 3%, and 6% crosslinks by a substitution reaction, in order to synthesize resin. These synthetic resins were confirmed by chlorine content, elementary analysis and IR-spectrum. As the results of the effects of pH, equilibrium arrival time, crosslink of synthetic resin, and dielectric constant of a solvent on uranium ion adsorption for resin adsorbent, the uranium ion showed high adsorption at pH 3 or over and adsorption equilibrium of uranium ion was about 2 hours. In addition, adsorption selectivity for the resin in methanol solvent was the order of uranium (UO2 2+) > iron (Fe3+) > lutetium (Lu3+) ions, adsorbability of the uranium ion was in the crosslinks order of 1%, 2%, 3%, and 6% was increased with the lower dielectric constant.

We propose a mean value function for software failures in NHPP software reliability model. And we deal with the maximum likelihood estimation and the least squares estimation in the proposed mean value function. The explicit mean value function solution for the proposed model is presented by MLE and LSE in two data sets. The values of SSE and MSE is presented in two data sets by MLE and LSE. We compare the predicted number of faults with the actual two data sets using the proposed mean value function.

Korea, which is located in the middle-latitude area of the northern hemisphere, has four seasons. These seasons can be classified based on their months, mean temperatures, biology and natural phenomena. In this study, climatic changes were identified by biotic and temperature seasons, changing trends were compared by season, and the appropriateness of the biotic phenomena for the biotic season classification was examined. The data for this study included the mean temperatures, and biology · phenomenon observation dates, which had been observed for 38 years from the ASOSs in seven Gwangju and Jeonnam regions. Limitations were found in the classification of the temperature and biotic seasons. Especially in the case of the biotic season based on a single life, the points of the first sighting and the initial sound fluctuated so much that the accuracy of the results was not guaranteed. Therefore, the life species had to be selected subject to detailed verification and accurate specifications, and to be applied to the meteorological phenomena. In addition, there were lives in the standard biology that could no longer be observed because of environmental pollution and climatic change, which indicates the need to protect the existing standard biology.