Photochemical Activities of N‐Nitroso Carboxamides and Sulfoximides and Their Application to DNA Cleavage

N‐Nitroso compounds containing benzene, fluorene or fluorenone rings were synthesized. Photolysis of these compounds with 312‐nm UV light provided the NO ^. species, the presence of which was corroborated by use of an EPR method and of 2‐phenyl‐4,4,5,5‐tetramethylimidazolin‐1‐oxyl 3‐oxide (PTIO) as a trapping agent. During irradiation of N‐methyl‐N‐nitroso‐9‐fluorenone carboxamide ( 14 c ) in the absence of PTIO, it underwent decomposition followed by recombination to give the heterocyclic nitric oxide radical 15 . Incorporation of intercalating moieties endowed the N‐nitroso compounds with DNA‐cleaving ability through single‐strand scission upon UV irradiation in a phosphate buffer (pH 5.0–8.0) under aerobic conditions.     

Juncenolides H – K,New Briarane Diterpenoids from Junceella juncea

Chemical investigation of the Taiwanese gorgonian coral Junceella juncea resulted in the isolation of four new briarane‐type diterpenoids, juncenolides H, I, J, and K ( 1 – 4 ). Their structures were determined on the basis of spectroscopic analysis, especially 1‐ and 2D‐NMR. The inhibitory effects of compounds 1 – 4 on superoxide‐anion generation and elastase release by human neutrophils were evaluated.     

A novel architecture of poly(tetrafluoroethylene)-framed TiO2 electrodes for dye-sensitized solar cells

A novel architecture of polytetrafluoroethylene (PTFE)-framed TiO₂ electrodes is developed for dye-sensitized solar cells. The PTFE-framed TiO₂ electrodes with various thicknesses have been successfully fabricated, ranging from 20 to 160 μm. The optimal energy conversion efficiency of 9.04% is achieved with a film thickness of 60 μm. The PTFE-framed structure not only provides tunable film thickness but a reliable and cost-effective way for the mass production of photo-electrodes.     

Observation of a new rotational band in 104Nb nucleus

The high spin states in neutron-rich 104Nb have been investigated from study of prompt γ-rays in spontaneous fission of 252Cf with the Gammasphere detector array. A new rotational band has been identified for the first time. This band is proposed as a semi-decoupled band based on the configuration π5/2-[303](⊕)v1/2-[541].     

Size effect in plastically deformed passivated thin films

The flow theory of mechanism-based strain gradient plasticity theory (MSG) developed by Qiu et al. (2003) is extended for incompressible material. The MSG flow theory is used to predict the increase of plastic work hardening for plane strain tension of surface-passivated Cu thin film. The theoretical predictions agree well with experiments for suitably chosen material parameters. Contributed by HWANG Keh-Chih     

Far-field spectral intensity characteristics of a time-dependent gaussian pulse from a circular mask with a linear circular apertures array

The spectral characteristics of a time-dependent Gaussian pulse from a circular mask with a circular apertures array in the far field are theoretically investigated and presented with numerical results. A rigorous treatment, with the Fresnel diffraction integral, to the spectral changes of a time-dependent Gaussian-shaped pulse passing through a circular mask with a linear circular apertures array is given and some properties of the spectral intensity under different situations are provided. Also an accurate and concrete criteria judging the condition for the red shift, blue shift of spectral intensity distributions is obtained as well.     

Influence of reactive oxygen species on the sterilization of microbes

The influence of reactive oxygen species on living cells, including various microbes, is discussed. A sterilization experiment with bacterial endospores reveals that an argon–oxygen plasma jet very effectively kills endospores of Bacillus atrophaeus (ATCC 9372), thereby indicating that oxygen radicals are the key element of sterilization. Ozone in acidic water also kills endospores of B. atrophaeus very effectively, demonstrating the capability of cleaning a large surface area contaminated by toxic biological agents. The viable microbe numbers after the contact with acidic ozone water directly correlate with increase in the ozone decay time in water after lowering the pH value of water from pH = 7 to 4 indicating that acidic ozone water is an effective means of sterilizing microbes. However, advanced cells such as fertilized eggs were not greatly influenced by the acidic ozone water. Also, both human and canine cells after treatment with the acidic ozone water prospered without showing signs of stress due to ozone in acidic water. This study suggests that antioxidant enzymes such as superoxide dismutase can be developed in the advanced cells to protect themselves from attacks by reactive oxygen species. Meanwhile, the advanced cells utilize oxygen by certain enzymes, proliferating life on earth.     

Optimal Gradient Estimates and Asymptotic Behaviour for the Vlasov–Poisson System with Small Initial Data

The Vlasov–Poisson system describes interacting systems of collisionless particles. For solutions with small initial data in three dimensions it is known that the spatial density of particles decays as t ⁻³ at late times. In this paper this statement is refined to show that each derivative of the density which is taken leads to an extra power of decay, so that in N dimensions for N \geqq 3{N \geqq 3} the derivative of the density of order k decays as t ^−N-k . An asymptotic formula for the solution at late times is also obtained.     

Change in microstructure and surface properties of electrospray-synthesized silica layers

Silica layers with different microstructures were prepared by electrospraying. The microstructure of the layers was changed by controlling the viscosity of the precursor solutions in the electrospray deposition. Precursor solutions of low viscosity produced particulated silica layers, exhibiting superhydrophobicity. In contrast, fibrous silica layers exhibiting superhydrophilicity were attained with viscous precursor solutions. In particular, the particulated silica layers showed a good durability and resistance to ultraviolet illumination. The dramatic change in the wettability of silica layers without any chemical treatment is promising in speeding up their use in many fields.     

Synthesis of large ring 3,4-alkylenedioxythiophenes (ADOT) derivatives via Mitsunobu reaction

Poly(3,4-ethylenedioxythiophene) (PEDOT) stands out for its optimized conductivity, stability, and high degree of transparency which has led to its successful commercialization. These excellent properties of PEDOT are mostly ascribed to the alkylenedioxy bridge across the 3- and 4-positions, and thus much effort has been dedicated to synthesizing 3,4-ethylenedioxythiophene (EDOT) analogs. However, only few homologous compounds were successfully synthesized, such as 3,4-propylenedioxythiophene (PrDOT) or 3,4-(1,4-butylenedioxy)thiophene (BuDOT). In this Letter, we use Mitsunobu reaction to synthesize a series of 3,4-alkylenedioxythiophenes (ADOTs) derivatives with 8- to 16-membered rings. The eight-membered compounds were obtained in high or excellent yield. We also found that the 9- to 16-membered EDOT analogs were obtained in relatively low yield because of the competitive reaction to make dimers. Our method provides an easy way to modify ethylenedioxythiophenes (EDOTs), and these obtained ADOTs compounds are promising building blocks for the synthesis of functional π-conjugated systems used in material chemistry.