Effects of Purified Persimmon Tannin and Tannic Acid on Survival and Reproduction of Bean Bug, Riptortus clavatus

We evaluated the effects of tannic acid and purified perrsimmon tannin on survival and reproduction of bean bugs, Riptortus clavatus.Feeding behavior of R. clavatus was also examined on sweet (cv. Fuyu) and astringent (cv. Chongdosi) persimmon fruits. Soluble tannin in sweet persimmon fruits decreased from 3% in early June to 0.5% in late September, but it increased from 2 to 8% during the same period in astringent persimmon fruits. More bugs visited sweet than astringent persimmon. Numbers of piercing/sucking spots were higher on sweet than on astringent persimmon. When fed 1 and 3% solutions of persimmon tannin, adult bugs ingested only 64.1 and 9.5% of the amount of water ingested by those offered the control (distilled water). Amounts of persimmon tannin ingested by the adult bugs were 6.5 and 2.8 times higher at 1 and 3% tannin solutions compared to a 0.1% solution. Persimmon tannin exerted negative effects on survival and reproduction of R. clavatus at higher concentrations (1 and 3% solutions). Feeding of R. clavatus adults decreased with increasing tannin concentrations. When results from both sexes were pooled, 50% mortality was achieved at 11 and 4 days after treatment with the 1 and 3% tannin solutions, respectively. Reproduction decreased with 1% tannin, and no eggs were produced with 3% tannin solution. Tannic acid was similar in its effects on R. clavatus. All nymphs died 14, 12, and 7 days after feeding on 0.1, 1, and 3% tannic acid, respectively. Adults were less sensitive than nymphs, and their survival was not affected by 0.1% tannic acid. However. 1 and 3% tannic acid solutions were fatal. Survivorship decreased to 50% at 11 and 6 days after supplying tannin solutions of 1 and 3% concentrations. Higher concentrations (1 and 3%) resulted in reduced reproduction, as was seen with persimmon tannin. Our data may explain why R. clavatus does not invade sweet persimmon orchards until late July, when concentrations of soluble tannin are low enough to allow them to feed.     

Molecular aspects of the transport and toxicity of ochratoxin a

Ochratoxins are a class of naturally occurring compounds produced by several fungi. The most toxic is ochratoxin A (OTA), and occurrence of some human nephropathies and tumors correlate with enhanced OTA exposure. In this Account, the following areas are examined: molecular details of the binding of OTA to human serum albumin (HSA), the influences of binding to HSA on the trans-port of OTA across epithelial cell membranes by organic anion transport proteins, the oxidative activation of OTA, and the formation of OTA adducts with biological molecules. These studies are beginning to provide a detailed chemical model for the trans-port, accumulation, and genotoxic and carcinogenic effects of OTA.     

SEQUENTIAL LOOP CLOSING IDENTIFICATION OF MULTIVARIABLE PROCESSES USING THE BIASED RELAY FEEDBACK METHOD

Each controller in multiloop control systems for multivariable processes can be tuned sequentially with the ultimate information for the paired input and output while former loops have been closed, and hence, single-input single-output autotuning methods can be applied. In this sequential autotuning for multiloop control systems, several iterations are usually required for better control performances. Especially when pairings are undesirable, the autotuning sequences should be repeated with correct pairings, which result in long field experiments. Here, to avoid this drawback, a simple method to identify process models while loops are being sequentially tuned is proposed. The identified models can be used to correct pairings of multiloop control systems and to improve tuning performances without several field iterations. In addition, they can be used to obtain model-based control systems such as decoupling control systems.     

Local structure and photocatalytic activity of B2O3–SiO2/TiO2 ternary mixed oxides prepared by sol–gel method

The local structure and the photoactivity of B₂O₃–SiO₂/TiO₂ ternary mixed oxides (SiO₂ content was fixed as 30 at.% with respect to TiO₂) was investigated by using XRD, FT-IR, BET, UV-vis spectra, and electron paramagnetic resonance (EPR) measurement. In FT-IR analysis, boron was incorporated into the framework of titania matrix with replacing Ti---O---Si with Si---O---B or Ti---O---B bonds. Also, paramagnetic species such as O⁻ and Ti³⁺ defects were formed by the boron incorporation. In SiO₂/TiO₂ mixed oxides, a blue shift in the light absorption band was observed due to the quantization of band structure. All B₂O₃–SiO₂/TiO₂ samples had pure anatase phase and no rutile phase was formed even though the calcination temperature was over 900 °C. Incorporating boron oxides of more than 10% enlarges the grain size of anatase phase and causes a red shift of the light absorption spectrum. The surface area was monotonically decreased with increasing the content of boron content. As a result, the photoactivity of B₂O₃–SiO₂/TiO₂ ternary mixed oxides was greatly influenced by the content of boron oxide. The highest photoactivity (g moles/min l) was obtained when the boron content was 5% and seven times higher than that of silica/titania binary mixed oxide. In addition, the specific photoactivity (g moles/m² l) was maximum still at 5%. It was concluded that the large reduction of surface area, the change of band structure, and more formation of bulk Ti³⁺ sites are responsible for the deterioration in the photoactivity of B₂O₃–SiO₂/TiO₂ ternary mixed oxides when the content of boron is over 10%, although their crystallinity was enhanced by increasing the calcination temperature with keeping anatase phase.     

The characteristics of microbial ecosystem response with the changes of hydrolic retention time on an aerobic fixed-biofilm biological nutrient removal system

The influence of an aerobic fixed-biofilm activity, microbial ecosystem and mass transfer with respect to HRT variation in a BNR (biological nutrient removal) system has been investigated in this study. The process used in this study was an anoxic (1)/aerobic (1)/anoxic (2)/aerobic (2) system. The study was demonstrated by several kinds of techniques such as INT-dehydrogenase activity (DHA), INT (2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetra-zolium chloride), DAPI (4’,6’-diamidino-2-phenylindole hydrochloride), and microelectrode. The study used by synthetic wastewater and HRT variation demonstrated that the DHA activity, density and heterotrophs/autotrophs ratio increased, as the HRT decreased from 8 hr to 4 hr. In comparing two aerobic reactors in fixed-biofilm process, the first aerobic reactor of the higher C/N ratio showed higher heterotrophs/autotrophs ratio and microbial activity than the second aerobic reactor. It was therefore concluded that the heterotrophs/autotrophs ratio and microbial activity were a greater influence on the first aerobic reactor, as organic loading rate was increased by HRT variation.     

Three-zone simulated moving-bed (SMB) for separation of cytosine and guanine

Separation of guanine and cytosine base pairs in nucleotide is an interesting topic for investigation of DNA structure. Therefore, an understanding of nucleotide separation by chromatography is necessary to prepare DNA molecules. Guanine and cytosine separation in SMB was simulated by Aspen chromatography and it was experimented by assembled 3-zone simulated moving bed (SMB) with change of stream flow rates, sample concentration, and desorbent flow rate. The simulation of batch chromatography was also confirmed by HPLC experiments. Based on these, good operating conditions of SMB chromatography were determined. Three-zone SMB equipment was set up by connecting three C₁₈-HPLC columns, four HPLC pumps, and six multiposition valves. Batch chromatography of cytosine and guanine was conducted to determine the isotherms of the two nucleotides. The outlet streams of SMB, raffinate and extract were sampled and analyzed by analytical HPLC system. The adsorption isotherms of cytosine and guanine were H_C= 0.5 and H _G =1.05. The highest experimental purity of cytosine and guanine in SMB was obtained as 94.9% and 89.8% with operating parameters of Q _feed =0.2 mL/min, Q _desorbent =0.6 mL/min, Q _extract =0.2 mL/min, Q _raffinate =0.6 mL/min, and switching time=7 min.     

Biodegradable polycaprolactone/cuttlebone scaffold composite using salt leaching process

We prepared biodegradable polycaprolactone/cuttlebone scaffold composite by salt leaching process. In the first step, a co-continuous blend of biodegradable materials, polycaprolactone (PCL) and cuttlebone (CB), and an amount of sodium chloride salt particles were mixed using a stirrer. Next, the extraction of mineral salts using de-ionized distilled water was performed using a biodegradable PCL/CB scaffold with fully interconnected pores. Finally, the durable morphology of the scaffolds was fabricated by freeze-drying process at ?53 °C for 24 hrs in a vacuum. In addition, the quadrilateral pres ranged from about 250 to 300 ??m in diameter. Scanning electron microscopy (SEM) and mercury intrusion porosimeter techniques were carried out to characterize the pore morphology. By increasing the CB and sodium chloride salt particle content, the number of interconnected pores, material properties, and pore morphology were dramatically changed. The average compressive strengths (load at 50% strain) of the different porous PCL/CB scaffolds were found to decrease from 133 to about 79 (load at 50% strain, gf) with an increase in porosity. The values of the porosity increased as the sodium chloride salt volume fraction increased     

Separation of N2/SF6 binary mixtures using polyethersulfone (PESf) hollow fiber membrane

PESf hollow fiber membrane was used to recover sulfur hexafluoride (SF₆) from N₂/SF₆ binary mixture gas. To fabricate a hollow fiber membrane, a dry-wet phase inversion method was used. Fiber was post-treated by methanol to increase permeance. Fabricated membrane was characterized by scanning electron microscopy (SEM) and N₂, SF₆ single gas permeation according to temperature and pressure difference. Using N₂/SF₆ binary mixture gas (10 vol% of SF₆), we checked the separation of mixture gas in a manufactured single module according to temperature, pressure difference, and retentate flow rate. The highest SF₆ purity in recovered gas was 50.4 vol% when the pressure difference, temperature, and stage cut was highest in experimental conditions, but the recovery ratio marked the lowest value.     

Cost of energy analysis of integrated gasification combined cycle (IGCC) power plant with respect to CO2 capture ratio under climate change scenarios

This paper presents the results of the cost of energy (COE) analysis of an integrated gasification combined cycle (IGCC) power plant with respect to CO₂ capture ratio under the climate change scenarios. To obtain process data for a COE analysis, simulation models of IGCC power plants and an IGCC with carbon capture and sequestration (CCS) power plant, developed by the United States Department of Energy (DOE) and National Energy Technology Laboratory (NETL), have been adopted and simulated using Aspen Plus. The concept of 20-year levelized cost of energy (LCOE), and the climate change scenarios suggested by International Energy Agency (IEA) are also adopted to compare the COE of IGCC power plants with respect to CO₂ capture ratio more realistically. Since previous studies did not consider fuel price and CO₂ price changes, the reliability of previous results of LCOE is not good enough to be accepted for an economic comparison of IGCC power plants with respect to CO₂ capture ratio. In this study, LCOEs which consider price changes of fuel and CO₂ with respect to the climate change scenarios are proposed in order to increase the reliability of an economic comparison. And the results of proposed LCOEs of an IGCC without CCS power plant and IGCC with CCS (30%, 50%, 70% and 90% capture-mole basis- of CO₂ in syngas stream) power plants are presented.     

A study on thermal analysis of MgH2 powder made by hydriding chemical vapor deposition method

The desorption kinetics of Mg hydride made by the HCVD method was assessed by thermal analysis in order to study desorption behavior. Desorption kinetics was analyzed by the theoretical equation which was derived on the basis of a continuous moving boundary model. At various initial hydride wt% from 1.65 to 7.42, the sample was heated to 573 K at a rate of 1.0 K/min. The starting temperature of evolution of hydrogen rises higher as the initial hydride wt% increases. The number of thermal desorption peaks corresponds to the occupation sites of hydrogen. As the heating rate was increased, the peak temperatures increased; the peak temperatures for heating rates 1, 2, 3 and 4 K/min were 667, 683, 690 and 698 K, respectively. The pressure range is 0.1 to 0.2 atm for measuring. The activation energy for the decomposition of Mg hydride made by HCVD method was 166 kJ/ mol.