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This paper represents the first study to simulate the biodegradation rates (BDRs) of several components in the sewer using the sewer biodegradation model (SBDM). In order to verify the fitness between the experimental values and model values, experiments were conducted in a 21 m long sewer pilot plant and the results showed high fitness (All correlational coefficient values were greater than 0.91). Since the SBDM was validated, the biodegradation rate (BDR) was simulated. The production of hydrogen sulfide was also simulated. The results revealed that aerobic growth of heterotrophs in biofilm predominated the biodegradation. The growth rate of heterotrophs in biofilm was greater than the decay rate from initial time to the 3rd hour, but it changed after the 4th hour because of low substrate concentration. During the experimental period, the BDRs were greater than the supply rate for five components. For two components, the supply rates were greater than the BDRs. The BDR of dissolved oxygen was greater than the supply rate before the 3rd hour but that reversed after the 3rd hour. According to the results, the sewer biodeterioration could be simulated using SBDM.

The Al-5Ti-1B, Al-10Ti, Al-4B master alloys and TiB2 powder were applied to refine the pure aluminum, respectively. The effects of the TiAl3 phase, TiB2 particle, and AlB2 phase on the grain size of pure aluminum were compared. The grain refinement mechanism of the Al-5Ti-1B grain refiner was studied. The results showed that the TiAl3 phase was an effective heterogeneous nucleus of the α-Al grain. But the TiAl3 phase in the Al-5Ti-1B grain refiner was not the heterogeneous nucleus of the α-Al grain due to its re-melting in the Al melt. The separate TiB2 particle or AlB2 phase was not the heterogeneous nucleus of the α-Al grain. However, the TiB2 coated by the TiAl3 phase can be the effective heterogeneous nucleus of the α-Al grain. The grain refinement mechanism of the Al-5Ti-1B grain refiner can be summarized as follows: when the Al-5Ti-1B grain refiner is added into the Al melt, the TiAl3 phases are re-melted to release the Ti atoms, while the TiB2 particles are remaining in the Al melt. During the solidification of the Al melt, the Ti atoms are segregating on the surface of TiB2 particles to form the TiAl3 phases. The TiB2 particles coated by the TiAl3 phases then reacts with the Al melt to generate α-Al crystal nucleus.

The effects of La and Ce mixed rare earth on the microstructure and properties of Al-0.75Mg-0.6Si alloy were studied by optical microscopy, digital eddy current conductive instrument and tensile testing machine. Results showed that the addition of La and Ce mixed rare earth had a positive effect on the grain refinement of Al-0.75Mg-0.6Si alloy, which is beneficial to improve the electrical conductivity and strength. With increasing the additive amount of La and Ce mixed rare earth, the electrical conductivity, tensile strength and elongation of Al-0.75Mg-0.6Si alloy gradually increased. When the additive amount of La and Ce mixed rare earth increased to 0.5%, the electrical conductivity of Al-0.75Mg-0.6Si alloy was 55.7% IACS, the tensile strength and elongation of Al-0.75Mg-0.6Si alloy were 236 MPa and 16.7%, respectively. The electrical conductivity increased by 5.7%, tensile strength and elongation increased by 11.3% and 15.2% compared with that of Al-0.75Mg-0.6Si alloy without adding the La and Ce mixed rare earth.

In the present investigation the casting-forging integrated technology was adopted to manufacture Al-1.1Mg-0.6Si-0.4Cu alloy automobile brake calipers. The effect of forging pressure on the microstructure and mechanical properties of Al-1.1Mg-0.6Si-0.4Cu alloy calipers were studied. The results showed that the shrinkage porosities and cracks in the Al-1.1Mg-0.6Si-0.4Cu alloy calipers could be removed by the forging process. The ultimate tensile strength and elongation of Al-1.1Mg-0.6Si-0.4Cu alloy calipers increased with the increase of forging pressure. When the forging pressure was 120 MPa, the ultimate tensile strength and elongation of Al-1.1Mg-0.6Si-0.4Cu alloy calipers with T6 heat treatment were 365.3 MPa and 11.5%, which were improved by 22.8% and 38.2%, respectively compared with that of Al-1.1Mg-0.6Si-0.4Cu alloy calipers without forging. The tensile fracture images revealed that the fracture modes of Al-1.1Mg-0.6Si-0.4Cu alloy calipers were more ductile at higher forging pressure.

The microstructure of Al-5Ti-1B grain refiner was analyzed by XRD and SEM. The effect of the Al-5Ti-1B grain refiner on the microstructure and mechanical properties of 7075 aluminum alloy were studied. Results show that when the addition amount of Al-5Ti-1B grain refiner is 0.1%, the microstructure of 7075 aluminum alloy is refined from coarse dendrite to equiaxed grains with an average diameter of 55.1μm. The tensile strength and elongation of 7075 aluminum alloy are improved by 11.32% and 36.04% compared with that of 7075 aluminum alloy without adding Al-5Ti-1B grain refiner. With increasing the addition amount of Al-5Ti-1B grain refiner from 0.1% to 0.5%, both the tensile strength and elongation are improved. When the addition amount of Al-5Ti-1B grain refiner increases to 0.5%, the microstructure of 7075 aluminum alloy is refined to uniform equiaxed grains with an average diameter of 32.5μm. The tensile strength and elongation are improved by 18.11% and 48.76%, respectively.

An Al-5Zr-1.1B grain refiner was prepared by in-situ synthesis from Al melt and K2ZrF4+KBF4 mixed powder. The microstructure of Al-5Zr-1.1B grain refiner was analyzed by XRD, SEM and EDS. The effect of Al-5Zr-1.1B grain refiner on the microstructure and mechanical properties of AZ91D magnesium alloy were studied. Results show that a large number of fine ZrB2 particles were observed in the Al-5Zr-1.1B grain refiner and the ZrB2 particles could act as the heterogeneous nuclei of α-Mg grains. With the increase of the addition amount of Al-5Zr-1.1B grain refiner, the α-Mg grains of AZ91D magnesium alloy were refined from coarse dendrites to equiaxed grains. When the addition amount of Al-5Zr-1.1B grain refiner increased to 0.6%, the α-Mg grains of AZ91D magnesium alloy were refined to fine equiaxed grains with an average diameter of 45 μm, and the tensile strength and elongation of AZ91D magnesium alloy were improved to 195.3 MPa and 3.94%, respectively. The α-Mg grains average diameter of AZ91D magnesium alloy decreased by 73.5% and the tensile strength and elongation improved by 25.9% and 27.9% compared with that of AZ91D magnesium alloy without adding the Al-5Zr-1.1B grain refiner. It is concluded that the Al-5Zr-1.1B is an effective grain refiner to refine the α-Mg grains of AZ91D magnesium alloy.

The effect of sludge retention time (SRT) on biomass, kinetic parameters, and stoichiometric parameters of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in anaerobic/anoxic/oxic (A2O) process were explored in this study. The results showed that the growth rate constants were 1.52, 1.22, and 0.85 day−1, respectively, for AOB, those were 1.59, 1.19, and 0.87 day−1, respectively, for NOB when SRT was 20, 10, and 5 days. The lysis rate constants of AOB and NOB were 0.14 and 0.09 day−1, respectively. The yield coefficients were 0.23 and 0.22, respectively, for AOB and NOB. They did not change with SRT obviously. The biomass of AOB was 50.94, 26.35, and 14.68 mg L−1, respectively, and the biomass of NOB was 116.77, 60.00, and 44.25 mg L−1, respectively, at SRT of 20, 10, and 5 days. When SRT diminished from 20 to 5 days, the biomass of AOB and NOB diminished by 36.26 and 75.52 mg L−1, respectively. The removal efficiency of NH4 +–N diminished by 68.9 %. The removal efficiency of total nitrogen diminished by 42.9 %.

The effect of applied forging pressure on microstructure and mechanical properties of 6061 aluminum alloy was examined. The results showed that the ultimate tensile strength, elongation and hardness of the alloy after heat-treated treatment increase with the applied forging pressure, and the corresponding highest values, 365MPa, 11.52% and 146.53HV, were obtained at the applied forging pressure of 120MPa. Compared to casting condition without forging pressure, the ultimate tensile strength, elongation and hardness can be increased by 22.8%, 98.2% and 48.7%, respectively. The defects such as the shrinkage pores and cracks were absent in the microstructure due to the applied forging pressure. The SEM observation indicated that the fracture mode of 6061 aluminum alloy is more ductile at higher applied forging pressure.

The effect of the sintering temperature, quartz and sodium phosphate content on the core strength,shrinking percentage and solubility of alumina matrix ceramic cores was investigated．The results show that：the more the quartz is, the higher of the bending, tensile strength at room temperature of core are;It has the extreme point when quartz is 10wt%, then decreases slightly.The shrinkage rate and the room temperature strength of core increases with the rising of sintering temperature,but decreases with the increasing of content of sodium phosphate. Furthermore, the effect of the sintering temperature,quartz powder and sodium phosphate content on solubility of core was discussed.

Continuous semisolid extruding extending forming process was adopted to produce LY11 alloy flat bar. The forming process, metal flow behavior in die cavity and microstructure and mechanical property of flat bar were investigated. It is shown that the LY11 alloy flat bar with transverse section of 10×50 mm and with good surface and fine equiaxed grains can be obtained by the continuous semisolid extruding extending forming process with melt pouring temperature of 770～780°C. The metal streamlines show that the semisolid slurry fills the die cavity in radiation manner and moves forward layer by layer and the velocity of slurry flow in the central area of die cavity is the maximum, and then decreases gradually from the center to side of die cavity. The tensile strength and elongation of flat bar with T6 heat treatment are 420.5 MPa and 14.2%, respectively.

BACKGROUND: Pesticides are sometimes non-biodegradable and, moreover, toxic to microorganisms. If pesticides exceed the tolerance of microorganisms, failure of the activated sludge process (ASP) occurs. Therefore the effects of two types of organophosphate pesticides on heterotrophic growth rate constant in sludge from ASP were investigated. Oxygen uptake rate was employed to measure the rate constants. RESULTS: The results indicated that the value of heterotrophic growth rate constant decreased from 3.88 d−1 to 1.46 d−1 or by 62% when 0.5 mg L−1 of glyphosate was added. When adding 0.5 mg L−1 of malathion, the value of heterotrophic growth rate constant decreased to 1.33 d−1 or by 66%. The value of heterotrophic growth rate constant decreased to 1.98 d−1 or by 49% when 0.5 mg L−1 of pesticide combination (50% for each) was added. CONCLUSIONS: The inhibitory effects of glyphosate and malathion were in good agreement with non-competitive inhibition kinetics, but pesticide combination did not follow non-competitive kinetics. The inhibition coefficient values for glyphosate, malathion and their combination were 0.29, 0.29 and 0.58 mg L−1, respectively. For comparison, linear and exponential types of models were derived by regression. According to non-competitive kinetics, and linear and exponential models, the inhibitory effects of glyphosate and malathion were almost consistent. Finally, the degree of inhibition was simulated using different types of model. It was found that the toxicity of the two pesticides agreed with the antagonism well. Copyright © 2009 Society of Chemical Industry

A two-step reheating process was proposed and applied to perform reheating experiments on the semi-solid 2024 alloy billet. In this process, the semi-solid billet was firstly heated over liquidus temperature and then isothermally held at solid-liquid zone temperature. Microstructure evolution of the semi-solid billet during two-step reheating was studied by optical microscope and compared with that during isothermal reheating. The results show that the remelting rate of the semi-solid billet during two-step reheating is faster than that during isothermal reheating. Under the same reheating time, the grains of the semi-solid billet reheated by two-step reheating process are finer and rounder than those by isothermal reheating process. The present experimental results indicate that accelerating the formation of liquid phase during the two-step reheating process can restrain the coalescence of grains to a certain extent, and thus refine the grain size and promote the grain spheroidization.

Cartap is an insecticide known to produce contraction and damage to mouse and rabbit diaphragms, and plays a pivotal role in respiratory paralysis and mortality in rabbits. The aim of this study was conducted to screen for the toxic properties and blood concentrations of commercialized cartap products in New Zealand White (NZW) rabbits. Five granular formulations (GRs) with different concentrations (4, 6, 6.5, 6.66 or 10%) and seven water-soluble powders (SPs, 50%) of commercialized cartap products were chosen to study toxicity following ocular instillation. Furthermore, ocular instillation (5, 12.5, 25 or 50 mg kg−1) and oral administration (25 mg kg−1) of the technical material (TC) cartap was also performed to compare blood concentration changes in rabbits. There was no death or eye irritation with all GR products; however, soluble powder (SP) products produced severe toxicity and mortality in rabbits. The blood concentration of TC cartap in rabbits started to increase from 2 min and reached peak level...

The purpose of this work is to evaluate the effect of thuringiensin on the adenylate cyclase activity in rat cerebral cortex. The cyclic adenosine 3'5'-monophosphate (cAMP) levels were shown to be dose-dependently elevated 17-450% or 54-377% by thuringiensin at concentrations of 10 microM-100 mM or 0.5-4 mM, due to the activation of basal adenylate cyclase activity of rat cerebral cortical membrane preparation. Thuringiensin also activated basal activity of a commercial adenylate cyclase from Escherichia coli. However, the forskolin-stimulated adenylate cyclase activity in rat cerebral cortex was inhibited by thuringiensin at concentrations of 1-100 microM, thus cAMP production decreased. Furthermore, thuringiensin or adenylate cyclase inhibitor (MDL-12330A) reduced the forskolin (10 microM)-stimulated adenylate cyclase activity at concentrations of 10 microM, 49% or 43% inhibition, respectively. In conclusion, this study demonstrated that thuringiensin could activate basal adenylate cyclase activity and increase cAMP concentrations in rat cerebral cortex or in a commercial adenylate cyclase. Comparing the dose-dependent effects of thuringiensin on the basal and forskolin-stimulated adenylate cyclase activity, thuringiensin can be regarded as a weak activator of adenylate cyclase or an inhibitor of forskolin-stimulated adenylate cyclase.

Cartap is extensively used to control agricultural pests. Pertinent literatures have indicated that it causes no eye irritation [D.E. Ray, Insecticides derived from plants and other organisms, in: W.J. Hayes, E.R. Laws (Eds.), Handbook of Insecticide Toxicology, Classes of Insecticides, vol. 2, Academic Press, New York, 1991, p. 611; C. Tomlin, Cartap, in: C. Tomlin (Ed.), The Insecticide Manual, 12th ed., British Crop Protection Council, Surrey, UK, 2000, p. 144]; however, the instillation of a little cartap through the eye has caused death in rabbits. The aim of this study was to determine the ocular toxicity of cartap in New Zealand White rabbits. Cartap was directly instilled into the low conjunctival sac of eyes, at doses of 0, 5, 7.5, 10 and 12.5 mg/kg body weight. The changes in the enzymes and isoenzymes of creatine kinase (CK), lactate dehydrogenase (LD), as well as pathological changes in the muscles of the heart, thigh and diaphragm were determined in the cartap-treated rabbits. Moreover, the neuromuscular effect of cartap was examined using the isolated rabbit phrenic-nerve diaphragm model. The results indicated that rabbits developed severe signs and they died within 20 min of ocular instillation. The ocular LD50 of cartap was 8.1 mg/kg body weight. Treatment with cartap increased the activities of CK and LD enzymes and their isoenzymes, CK-1, CK-2, and CK-3 in serum, and CK-3 and LD-5 in the diaphragm. Microscopically, hypercontraction bands and the rupture of myofibers of the diaphragm were observed in dead rabbits. Cartap did not affect nerve-evoked twitch but induced irreversible contracture and twitch depression on the isolated rabbit's diaphragm. These results indicate that the rabbit is susceptible to cartap toxicity; the effect of cartap caused contracture and damage to the diaphragm might play a pivotal role in respiratory paralysis and death of rabbits during intoxication.

The ion migration in polymer solutions of different molecular weights is investigated by conductometry for various inorganic salts. The electric conductivity κ declines with increasing the number c...

The partition of ionic surfactants (sodium alkyl sulfate and alkyl trimethyl ammonium bromide) between phosphatidylcholine vesicles and aqueous phase is investigated by simple conductometry under different temperatures. The experimental results can be well represented by the proposed regular solution theory and the thermodynamic parameters satisfy the thermodynamic consistency. The deviation from ideal partition is manifested through the effective interaction energy between lipid and surfactant wb, which is O(kT) large. It is found that wb rises as the alkyl chain is decreased for a specified head group. This is attributed to significant mismatch of chain lengths between surfactant and lipid molecules. The partition coefficient K declines with increasing temperature. The energy barrier from bilayer to aqueous phase, Δμ/kT∝ln K, is in the range of 16–26 kJ/mol. As the alkyl chain length is decreased for a given head group, Δμ is lowered by 1.3–1.5 kJ/mol per methylene group. Two independent analyses are em...

The purpose of this work is to evaluate the pulmonary toxicity of purified thuringiensin in Sprague–Dawley rats. Rats were intratracheally instillated with 0, 0.4, 0.8, 1.6, 3.2, 6.4 and 9.6 mg/kg body weight of thuringiensin. The results indicated that the acute pulmonary LD 50 of thuringiensin for rats was 4.4 mg/kg. The total number of inflammatory cells and lactate dehydrogenase (LDH) activity in the bronchoalveolar lavage (BAL) fluid increased in a dose-dependent manner after thuringiensin instillation. Furthermore, an effective dose of 1.6 mg/kg was selected for the time course study of pulmonary toxicity. The treated animals showed a significant increase in the weights of the lungs, hydroxyproline levels in the lungs and total number of cells in BAL fluid 2, 4, 7, 14, 28 and 56 days after treatment. In comparison with the control, the total protein concentrations in BAL fluid were increased by 361, 615, 116, 41, 34 and 41%, after 2, 4, 7, 14, 28 and 56 days, respectively. The LDH activity in BAL fluid showed a significant increase after 1, 2, 4, 7, 14, 28 and 56 days. The increases in fibronectin levels were 164, 552, 490, 769, 335, 257 and 61% at the corresponding times, but neither tumor necrosis factor nor interleukin-1 increased. The treated rats presented abnormal histology including distributed inflammation in the bronchioles and alveoli, bronchial cellular necrosis on days 1 and 2, and areas of septal thickening with cellular infiltration and collagen deposit in the intestinal and alveolar spaces on days 4–56. Based on these biochemical and pathological parameters, intratracheal instillation of purified thuringiensin might cause significant pulmonary toxicity in rats.

The second virial coefficients Bij (nm3) of poly(ethylene glycol) with molecular weight M = 600−104 in water are measured by freezing point depression. B12 represents the virial cross coefficient for two PEG solutes with different molecular weights M1 and M2. B11 can be well described by the scaling law M3ν with ν ≃ 0.60. That is, the good solvent behavior is observed even for such low molecular weight. In terms of the hard-sphere model, the effective diameter of PEG ranges from 1.3 to 7.9 nm. Since the second virial coefficient is generally increased with decreasing temperature, our results at freezing point provide an upper bound. The virial cross coefficient is found to follow B12 = B11[1 + (M2/M1)ν]3/8. This result indicates that the effective hard-sphere picture is also reasonable for dilute solutions of different polymer molecules in good solvents.

The effect of sludge retention time (SRT) on biomass, kinetic parameters, and stoichiometric parameters of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in anaerobic/anoxic/oxic (A(2)O) process were explored in this study. The results showed that the growth rate constants were 1.52, 1.22, and 0.85 day(-1), respectively, for AOB, those were 1.59, 1.19, and 0.87 day(-1), respectively, for NOB when SRT was 20, 10, and 5 days. The lysis rate constants of AOB and NOB were 0.14 and 0.09 day(-1), respectively. The yield coefficients were 0.23 and 0.22, respectively, for AOB and NOB. They did not change with SRT obviously. The biomass of AOB was 50.94, 26.35, and 14.68 mg L(-1), respectively, and the biomass of NOB was 116.77, 60.00, and 44.25 mg L(-1), respectively, at SRT of 20, 10, and 5 days. When SRT diminished from 20 to 5 days, the biomass of AOB and NOB diminished by 36.26 and 75.52 mg L(-1), respectively. The removal efficiency of NH4 (+)-N diminished by 68.9 %. The removal efficiency of total nitrogen diminished by 42.9 %.

This paper reports the occurrence of two new species of Digamasellidae from Taiwan, Dendroseius vulgaris n. sp. and Dendrolaelaps (Foveodendrolaelaps) linjianzheni n. sp. Dendroseius vulgaris is described based on the morphology of adult females, adult males and deutonymph, and D. linjianzheni is based on the morphology of adult females and males. This is the first report on the mite species of Digamasellidae from Taiwan.

Cartap, a nereistoxin analogue pesticide, is reported to have no irritation to eyes in rabbits. However, we have demonstrated recently that cartap could actually cause acute death in rabbits via ocular exposure. Our preliminary study with isolated mouse phrenic nerve diaphragms has shown that instead of neuromuscular blockade, cartap caused muscular contracture. The objective of the study was to examine the effect of cartap on the neuromuscular junction in more detail and to investigate its possible underlying mechanism with isolated mouse phrenic nerve diaphragms and sarcoplasmic reticulum (SR) vesicles. Cartap or nereistoxin at various concentrations was added in the organ bath with isolated mouse phrenic nerve diaphragm and both nerve- and muscle-evoked twitches were recorded. Instead of blocking the neuromuscular transmission as nereistoxin did, cartap caused contracture in stimulated or quiescent isolated mouse phrenic nerve diaphragm. Both the cartap-induced muscular contracture force and the time interval to initiate the contracture were dose-dependent. The contracture induced by cartap was not affected by the pretreatment of the diaphragm with the acetylcholine receptor blocker alpha-bungarotoxin; the Na(+) channel blocker tetrodotoxin; or various Ca(2+) channel blockers, NiCl(2), verapamil, and nifedipine. On the contrary, the contracture was significantly inhibited when the diaphragm was pretreated with ryanodine or EGTA containing Ca(2+)-free Krebs solution or in combination. This suggested that both internal and extracellular Ca(2+) might participate in cartap-induced skeletal muscle contracture. Moreover, cartap inhibited the [(3)H]-ryanodine binding to the Ca(2+) release channel of SR in a dose-dependent manner. Additionally, cartap could induce a significant reduction in Ca(2+)-ATPase activity of SR vesicles at a relatively high dose. The results suggested that cartap might cause the influx of extracellular Ca(2+) and the release of internal Ca(2+), with subsequent induction of muscular contracture in the isolated mouse phrenic nerve diaphragm. Based on these findings, we propose that the acute death of rabbits following ocular exposure to cartap might have resulted from respiratory failure secondary to diaphragm contracture.

Various formulations of agricultural chemicals, including solutions, wettable powders, and emulsifiable concentrates, contain adjuvants of solvents and surfactants in addition to active ingredients. Among these formulations, herbicides are among the most commonly used pesticides globally. Some pesticides have been demonstrated to cause severe circulatory failure in poisoned humans. To clarify the potential risk of herbicides and their adjuvants influence on the cardiovascular system, four technical grade (TG) herbicides and their end products (EP), including paraquat, glyphosate, glufosinate, and atrazine, as well as their formulated adjuvants isopropylamine (IPA), polyoxyethylene alkylether sulfate (AES), ethyl acetate (EA), xylene, petrolium-170 (P-170), and solvesso-100 (S-100), were assessed to determine their effects on isolated rat aorta and heart. The results revealed that the vasorelaxation effects of the herbicide EPs exceeded those of TGs, and atrazine produced more significant vasorelaxation in rat aortas than the other herbicides tested. The formulated adjuvants of IPA did not affect the aorta; however, AES, EA, xylene, P-170 and S-100 caused significant vasorelaxation. Herbicide EPs-induced vasorelaxation was generally endothelium-dependent. Furthermore, the TG and EP of paraquat, and the TG of glufosinate and glyphosate were found to have no effect on the isolated heart. However, the normal twitch tensions of the isolated heart were significantly inhibited by EPs of glyphosate and glufosinate, and by TG and EP of atrazine. Although, the adjuvants of IPA appeared unaffected, however, AES, EA, xylene, P-170 and S-100 caused complete inhibition and contraction on the isolated hearts. These results indicated that the adjuvants of herbicides might enhance hypotension and contributed to cardiovascular disorders during intoxication.

Our previous study has demonstrated that instead of neuromuscular blockage cartap, an organonitrogen insecticide, could cause a marked irreversible Ca2+-dependent contracture in both isolated mouse and rabbit phrenic nerve-diaphragms. We further examined the potential of direct myocytotoxicity of cartap and the possible roles of calcium ion and oxidative stress on cartap-induced muscle cell injury using the mouse myoblast cell line, C2C12. Cartap exerted a dose- and time-dependent cytotoxic effect in C2C12 cells measured by MTT colorimetric assay and trypan blue dye exclusion. The extracellular activities of both creatine kinase (CK) and lactate dehydrogenase (LDH) were elevated in the cartap-treated groups at or greater than 100 microM. The isoenzymatic profiles showed that the elevations were mainly due to CK-3, LDH-3, and LDH-4. Following the addition of 0.5-2.5mM EGTA, a Ca2+ chelator, or 30-100 microM verapamil, an L-type Ca2+ channel blocker, the cartap-induced reduction in MTT metabolic rate of C2C12 cells was significantly restored in a dose-dependent manner in both EGTA and verapamil-treated cells. Furthermore, EGTA could significantly reduce the cartap-induced elevation in the levels of total extracellular CK and LDH activities. Additionally, cartap significantly increased the level of endogenous reactive oxygen species (ROS) in C2C12 cells in a dose- and time-dependent manner. The cartap-induced ROS generation could be significantly inhibited by antioxidants, including Vitamins C and E, catalase, and superoxide dismutase, with catalase the most effective. EGTA could significantly inhibit cartap-induced ROS generation in a dose-dependent manner. The results suggested that cartap could induce ROS generation in C2C12 cells via a Ca2+-dependent mechanism resulting in subsequent cytotoxicity, at least partially, to C2C12 cells. It is speculated that both Ca2+ and Ca2+-induced ROS may also play the central role on the myogenic contracture and myofiber injury of the diaphragm leading to respiratory failure and subsequent death in rabbits exposed ocularly to cartap.

This study was designed to investigate the endocrine-disrupting activity of carbendazim-induced reproductive and developmental toxicity in Sprague-Dawley rats treated orally with the fungicide. Cotreatment of male rats with 675 mg/kg carbendazim and 50 or 100 mg/kg flutamide, an androgen receptor antagonist, once daily for 28 d blocked decrease of testis weight induced by treatment with carbendazim alone. The cotreatment prevented losses of spermatozoa and cell morphology and decrease of sperm concentration induced by carbendazim. Premating treatment of male and female rats with 200 mg/kg carbendazim for 28 d produced androgenic effects including incomplete development of uterine horn, enlargement of uretha, absence of vagina, and induction of seminal vesicles in female offspring, without marked effects in male offspring. Premating treatment with 100mg/kg benomyl, the parent compound of carbendazim, resulted in incomplete development of uterine horn and absence of vagina in female offspring and produced testis and epidydimis atropy in male offspring. Treatment of male rats with 25, 50, 100, 200, 400, and 800 mg/kg carbendazim for 56 d produced dose-dependent increases of androgen receptor concentrations in testis and epididymis. Additions of 5, 50, and 500 microM carbendazim to testis extract from untreated rats replaced binding of [3H]-5 alpha-dihydrotestosterone to androgen receptor in a concentration-dependent manner. The present study demonstrates that reproductive toxicity induced by carbendazim is blocked by an androgen receptor antagonist in male rats and developmental toxicity of the fungicide shows androgenic properties in female offspring. These results suggest that androgen- and androgen receptor-dependent mechanisms are possibly involved in carbendazim-induced toxicity.

The neutral polymer-micelle interaction is investigated for various surfactants by viscometry and electrical conductometry. In order to exclude the well-known necklace scenario, we consider aqueous solutions of low molecular weight poly(ethylene glycol) (2-20)x10(3), whose radial size is comparable to or smaller than micelles. The single-tail surfactants consist of anionic, cationic, and nonionic head groups. It is found that the viscosity of the polymer solution may be increased several times by micelles if weak attraction between a polymer segment and a surfactant exists, epsilon

This paper reports the occurrence of two new species of Digamasellidae from Taiwan, Dendroseius vulgaris n. sp. and Dendrolaelaps (Foveodendrolaelaps) linjianzheni n. sp. Dendroseius vulgaris is described based on the morphology of adult females, adult males and deutonymph, and D. linjianzheni is based on the morphology of adult females and males. This is the first report on the mite species of Digamasellidae from Taiwan.

Tetranychus okinawanus Ehara have recently been found in Taiwan. To date they have only been collected by the authors from several locations in the counties of Pingtung, Taitung, and Hualien and from one spot in Nantou County by Takafuji, all from non-crop plants. The authors examined the specific characteristics and made sketches of the leg chaetotaxy, the palpal terminal of both sexes and the male aedeagus. Collection records and observations of body color variations as well as a list of natural enemies are also provided. The ribosomal internal transcribed spacer 2 (ITS2) region of this mite was amplified by polymerase chain reaction and sequenced. The sequences are extremely rich in AT content (67.7%), and are identical among the tested individuals and identical to the neucleotide sequence of the ITS2 region of Tetranychus okinawanus reported from Japan.