Yingping Huang

Aligned gold nanoneedle arrays for surface-enhanced Raman scattering

A simple Ar(+)-ion irradiation route has been developed to prepare gold nanoneedle arrays on glass substrates for surface-enhanced Raman scattering (SERS)-active substrates. The nanoneedles exhibited very sharp tips with an apex diameter of 20 nm. These arrays were evaluated as potential SERS substrates using malachite green molecules and exhibited a SERS enhancement factor of greater than 10(8), which is attributed to the localized electron field enhancement around the apex of the needle and the surface plasmon coupling originating from the periodic structure. This work demonstrates a new technique for producing controllable and reproducible SERS substrates potentially applicable for chemical and biological assays.

Swimming capability and swimming behavior of juvenile acipenser schrenckii.

Acipenser schrenckii, the Amur Sturgeon, was a commercially valuable fish species inhabiting the Amur (Heilongjiang) River but populations have rapidly declined in recent years. Dams impede A. schrenckii spawning migration and wild populations were critically endangered. Building fishways helped maintain fish populations but data on swimming performance and behavior was crucial for fishway design. To obtain such data on A. schrenckii, a laboratory study of juvenile A. schrenckii (n = 18, body mass = 32.7 ± 1.2 g, body length = 18.8 ± 0.3 cm) was conducted using a stepped velocity test carried out in a fish respirometer equipped with a high-speed video camera at 20°C. Results indicate: (1) The counter-current swimming capability of A. schrenckii was low with critical swimming speed of 1.96 ± 0.10 BL/sec. (2) When a linear function was fitted to the data, oxygen consumption, as a function of swimming speed, was determined to be MO2  = 337.29 + 128.10U (R(2)  = 0.971, P < 0.001) and the power value (1.0) of U indicated high swimming efficiency. (3) Excess post-exercise oxygen cost was 48.44 mgO2 /kg and indicated excellent fatigue recovery. (4) Cost of transport decreased slowly with increased swimming speed. (5) Increased swimming speed led to increases in the tail beat frequency and stride length. This investigation contributed to the basic science of fish swimming behavior and provided data required for the design of fishways. Innovative methods have allowed cultivation of the species in the Yangtze River and, if effective fishways could be incorporated into the design of future hydropower projects on the Amur River, it would contribute to conservation of wild populations of A. schrenckii. The information provided here contributes to the international effort to save this critically endangered species. J. Exp. Zool. 319A:149-155, 2013.

Aerobic Swimming Performance of Juvenile Largemouth Bronze Gudgeon (Coreius guichenoti) in the Yangtze River

Largemouth bronze gudgeon (Coreius guichenoti), a fish species once abundant in the Yangtze River, has been rapidly declining in recent years. One important factor, among many, is the interruption of the free-flowing rivers by dams. To obtain data that can be applied to the design of an effective fishway for C. guichenoti and other species in the fish community, a laboratory study of juvenile C. guichenotis swimming ability and energetics was conducted in a flume-type respirometer equipped with a high-speed video camera system to record swimming behavior. The critical swimming speed (Ucrit ), standard metabolic rate (SMR), and maximum metabolic rate (MO2,max ) were determined during steady swimming at four water temperatures (10, 15, 20, and 25°C). A power function accurately describes the relationship between oxygen consumption rate (MO2 ) and swimming speed (U) at the four temperatures. The Ucrit , SMR, MO2,max , and metabolic scope increased with increasing temperature. The relationship between cost of transport (COT) and U was characteristically inverse bell-shaped, with minimum COT at Uopt = 4.5-5.0 body lengths per second (bl sec(-1)). This investigation provides data on the swimming ability of C. guichenoti that will add to the basic science required for fishway design.

Integrating water flow, locomotor performance and respiration of Chinese sturgeon during multiple fatigue-recovery cycles.

The objective of this study is to provide information on metabolic changes occurring in Chinese sturgeon (an ecologically important endangered fish) subjected to repeated cycles of fatigue and recovery and the effect on swimming capability. Fatigue-recovery cycles likely occur when fish are moving through the fishways of large dams and the results of this investigation are important for fishway design and conservation of wild Chinese sturgeon populations. A series of four stepped velocity tests were carried out successively in a Steffensen-type swimming respirometer and the effects of repeated fatigue-recovery on swimming capability and metabolism were measured. Significant results include: (1) critical swimming speed decreased from 4.34 bl/s to 2.98 bl/s; (2) active oxygen consumption (i.e. the difference between total oxygen consumption and routine oxygen consumption) decreased from 1175 mgO2/kg to 341 mgO2/kg and was the primary reason for the decrease in U crit; (3) excess post-exercise oxygen consumption decreased from 36 mgO2/kg to 22 mgO2/kg; (4) with repeated step tests, white muscle (anaerobic metabolism) began contributing to propulsion at lower swimming speeds. Therefore, Chinese sturgeon conserve energy by swimming efficiently and have high fatigue recovery capability. These results contribute to our understanding of the physiology of the Chinese sturgeon and support the conservation efforts of wild populations of this important species.

Heterogeneous Fenton Photodegradation of Microcystin-LR with Visible Light Irradiation

Under the condition of visible light irradiation (lambda>450 nm), the degradation mechanism of microcystin-LR was studied using H(2)O(2) and FeY catalyst, which is prepared by means of loading Fe(2+) to the molecular sieve NaY. The results indicate that the degradation rate of microcystin-LR is up to 90% in the wide pH range using Vis/FeY/H(2)O(2) system. Based on the intermediates detected by LC-MS analysis, the possible pathways and three vulnerable oxidation sites are put forward: (1) the conjugated double bonds of the Adda chain, (2) the methoxy group of the Adda chain, (3) unsaturated double bond of the Mdha chain. FeY catalyst is of good stability, having catalytic activity after 5 times repetition, which indicates its potential application to the control of the alga wastewater.

Removing organic contaminants by an electro-Fenton system constructed with graphene cathode

ABSTRACT The aim of the present investigation was to examine the use of a new electro-catalysis material graphene for electro-Fenton (EF) system to attain a more efficient degradation of organic contaminants, which adversely affect the aqueous ecosystem. The degradation of Rhodamine B (RhB), a toxic azo dye, using EF system was determined in an electrolysis cell with a fabricated graphene cathode. The electro-catalytic behavior of graphene cathode exposed to a 10 g/L disodium sulfate (Na2SO4) solution was studied utilizing cyclic voltammetry and electrochemical impedance spectroscopy methods. Results demonstrated that the EF system based on the graphene cathode effectively degraded RhB in situ by ultimately generating both hydrogen peroxide (H2O2) and hydroxyl radicals (·OH). The breakdown of RhB was determined by Fourier transform infrared spectroscopy and total organic carbon analysis, and data showed that the RhB was oxidized to some small molecules including carbon dioxide, carboxylic acids, and amines.

Degradation of 2, 4-D acid using Mn2+ as catalyst under UV irradiation

AbstractIn this paper, the oxidative degradation of 2, 4-dichlorophenoxyacetic acid (2, 4-D) using Mn2+/H2O2 reagent under UV irradiation was studied. The results show that 2, 4-D was degraded more completely in Mn2+/H2O2 solution than traditional Fenton solutions. The effects of the concentration of Mn2+, H2O2 and pH were also investigated. And under the optimal condition of

Electro-catalytic degradation of sulfisoxazole by using graphene anode.

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