Ultraviolet irradiation induced oxidative stress and response of antioxidant system in an intertidal macroalgae Corallina officinalis L.

The response of the antioxidant defense system of an intertidal macroalgae Corallina officinalis L.to different dosages of UV-B irradiation was investigated.Results showed that superoxide dimutase （SOD） and peroxidase （POX） increased and then maintained at a relatively stable level when subjected to UV-B irradiation.Catalase （CAT） activity under medium dosage of UV-B irradiation （Muv） and high dosage of UV-B irradiation （Huv） treatments were significantly decreased.Ascorbate peroxidase （APX） activity first remained unaltered and then increased in Huv treatment.In addition,the assay on isozymes was carried out using non-denaturing polyacrylamide gel electrophoresis （PAGE）.The activities of some SOD isoforms were altered by UV-B.Two new bands （POX V and POX VII） appeared upon exposure to all three UV-B dosages.CAT III activity was increased by low dosage of UV-B irradiation （Luv）,whereas CAT III and CAT IV disappeared when the alga was exposed to Muv and Huv.Two bands of APX （APX VI and APX VII） were increased and a new band （APX X） was observed under Huv exposure.H 2 O 2 and thiobarbituric acid reacting substance （TBARS） increased under Muv and Huv treatments.Overall,UV-B protection mechanisms are partly inducible and to a certain extent sufficient to prevent the accumulation of damage in C.officinalis.

Photoluminescence and thermoluminescence properties of dysprosium doped zinc metaborate phosphors

Polycrystalline powder samples of dysprosium doped Zn（BO2）2 phosphors were prepared by solid state reaction in air at high temperature and characterized by X-ray powder diffraction. The IR, Photoluminescence （PL）, diffuse reflectance and three-dimensional （3D） thermoluminescence （TL） emission spectrum after 60^Co gamma ray irradiation were investigated. The characteristic 3D TL emission bands at about 425, 481 and 573 um with a main emission band of around 573 um were attributed to the host emission, 4^F9/2→6H15/2 and F9/2→6^H13/2 f-f transitions of Dy^3＋ ions. No emission from Dy^2＋ ions was observed in the measurement wavelength range. The TL-dose response of the Zn（BO2）2：Dy polycrystalline powder sample to gamma ray radiation in the range from 1 to 100 Gy at clinical dose levels was almost linear. The experimental results showed that Zn（BO2）2：Dy had potential use as the materials of gamma-ray thermoluminescence dosimeter （TLD） for clinical dosimetry.

Effect of UV-B irradiation on interspecific competition between Ulva pertusa and Grateloupia filicina

We report the effect of UV-B irradiation(9.6 kJ m-2day-1)on interspecific competition between two species of macroalgae,Ulva pertusa(U)and Grateloupia filicina(G),in co-culture.Growth of U.pertusa and G.filicina was inhibited by UV-B irradiation in mono-culture and specific growth rate (μ)declined as a result.Interspecific competition between U.pertusa and G.filicina was closely related to the initial weights when co-cultured.When initial ratios of U.pertusa(U)to G.filicina(G)were U:G=1.2:1 and 1:1,U.pertusa was the dominant algae.When the initial U:G ratio was 1:1.2,G.filicina was competitively dominant in the earlier stage,but U.pertusa grew faster,superseding G.filicina in the later stage.At initial ration U:G=1:1.4,G.filicina was predominant.Under UV-B irradiation,the competitive ability of G.filicina was weakened and the interspecific competitive balance favored U.pertusa,which suggests that G.filicina was more sensitive to UV-B irradiation.We also probed the potential allelopathic effects between the two species,which led to mutual growth inhibition.

Facile and Convenient One-pot Synthesis of 1,1-Disubstituted Cyclopropanes in Water

A facile and convenient one-pot synthesis method of substituted cyclopropanes in water has been developed. A series of 1,1-disubstituted cyclopropanes 3 were synthesized from the reaction of β-dicarbonyl compounds 1 with 1,2-dibromoethane 2, in very high yields catalyzed by tetrabutylammonium bromide（TBAB） at 50 ℃ in the presence of K2CO3 in water. The catalyst TBAB in the aqueous phase can be reused after the separation of organic products.

CRISPR/Cas9系统:脑与认知科学研究的一个重要工具（英文）

Brain function is associated with the morphologies,organizations,synaptic connections,and circuit activities of neurons.As the building blocks of the brain,neurons display remarkable morphological diversity and form neural circuits with synaptic connections.Understanding the'wiring'connectomes among synapses and their roles in neural networks

How Do the Nucleons Pack in an Atomic Nucleus?

A nuclear structure model of “ring plus extra nucleon” is proposed. For nuclei larger than 4He, protons (P) and neutrons (N) are basically bound alternatively to form a ZP + ZN ring. The ring folds with a “bond angle” of 90° for every 3 continuous nucleons to make the nucleons packed densely. Extra N(‘s) can bind to ring-P with the same “bond angle” and “bond distance”. When 2 or more P’s are geometrically available, the extra N tends to be stable. Extra P can bind with ring N in a similar way when the ratio of N/P < 1 although the binding is weaker than that of extra N. Even-Z rings, as well as normal even-even nuclei, always have superimposed gravity centers of P and N;while for odd-Z rings, as well as all odd-A (A: number of nucleon) nuclei, the centers of P and N must be eccentric. The eccentricity results in a depression of binding energy (EB) and therefore odd and even Z dependent zigzag features of EB/A. This can be well explained by the shift of eccentricity by extra nucleons. Symmetrical center may present in even-Z rings and normal even-even nuclei. While for odd-Z ring, only antisymmetric center (every P can find an N through the center and vice versa) is possible. Based on this model, a pair of mirror nuclei, PX+nNX and PXNX+n, should be equivalent in packing structure just like black-white photo and the negative film. Therefore, an identical spin and parity was confirmed for any pair. In addition, the EB/A difference of mirror nuclei pair is nearly a constant of 0.184n MeV. Many other facts can also be easily understood from this model, such as the neutron halo, the unusual stability sequence of 9Be, 7Be and 8Be and so on.

Effects of Antifouling Technology Application on Marine Ecological Environment

Resolving the contradiction between Marine economic development and Marine ecological environment protection has become an unavoidable and sharp problem.The uncontrolled use of Marine antifouling technology will bring uncontrollable and even irreversible damage to the Marine biosphere,which will lead to ecological disaster and threaten the survival of human beings.Therefore,it is an urgent task to find antifouling technology with lower environmental toxicity under the premise of considering economy.More attention should be paid to the long-term impact of mature and new technologies on the Marine ecological environment.This paper introduces the development status of antifouling technology,its influence on Marine ecological environment and puts forward the design strategy of comprehensive biological fouling prevention and control technology.

Poly[(mercaptopropyl)methylsiloxane](PMMS)-based antibacterial polymer coatings prepared by a two-step sequential thiol–ene click chemistry

Poly[（mercaptopropyl）methylsiloxane] （PMMS）-based antibacterial polymer coatings have been prepared through a two-step sequential thiol-ene click chemistry utilizing 1-allyl-3-decylimidazolium bromide （ADIm） as antibacterial monomer and triallyl cyanurate （TAC） as the crosslinker. These films with different content of ADIm were characterized by thermogravimetric analysis （TGA）, dynamic mechanical analysis （DMA） and pencil hardness. It was found that the mechanical and thermal properties of these films were largely influenced by the content of ADIm in the films. Films with imidazolium bromide groups displayed excellent antimicrobial activity against Staphylococcus aureus with 100% killing efficiency.

Facile preparation of antibacterial polymer coatings via thiol-yne click photopolymerization

Novel antibacterial polymer coatings were prepared by a facile thiol-yne click photopolymerization of 1-propargyl-3-allYl-l,3-diazanyl-2,4-cyclopentadiene bromide （[PAIMIBr） and tetra（3-mercapto-pro- pionate）pentaerythritol （PETMP） （2：1 molar ratio） using 2,2-dimethoxy-2-phenylacetophenone （DMPA） as initiator. The antibacterial activity of the coatings was tested against Staphylococcus aureus （ATCC 292130） and Escherichia coli （ATCC 25922） by the dynamic shake method. The evaluation results revealed the antibacterial polymer coatings exhibited excellent inhibitory activity against S. aureus and E. coil, especially for S. aureus.