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Hydrogels with adjustable mechanical properties have been engineered as matrices for mammalian cells and allow the dynamic, mechano-responsive manipulation of cell fate and function. Recent research yielded hydrogels, where biological photoreceptors translated optical signals into a reversible and adjustable change in hydrogel mechanics. While their initial application provided important insights into mechanobiology, broader implementation is limited by a small dynamic range of addressable stiffness. Here, we overcome this limitation by developing a photoreceptor-based hydrogel with reversibly adjustable stiffness from 800 Pa to the sol state. The hydrogel is based on star-shaped polyethylene glycol, functionalized with the red/far-red light photoreceptor phytochrome B (PhyB), or phytochrome-interacting factor 6 (PIF6). Upon illumination with red light, PhyB heterodimerizes with PIF6, thus crosslinking the polymers and resulting in gelation. However, upon illumination with far-red light, the proteins dissociate and trigger a complete gel-to-sol transition. We comprehensively characterize the hydrogel’s light-responsive mechanical properties and apply it as reversible extracellular matrix for the spatiotemporally controlled deposition of mammalian cells within a microfluidic chip. We anticipate that this technology will open new avenues for the site- and time-specific positioning of cells and will contribute to overcome spatial restrictions.

Hexavalent chromium, Cr(VI), and trivalent chromium, Cr(III), are two chromium compounds with practical importance due to their high occurrence and solubility in the environment. Current Cr(VI) treatment techniques involve chemical reduction of Cr(VI) to Cr(III), which posed serious threat to workers and environment notably from long exposure and toxic fumes. Numerous reports have demonstrated the feasibility of using biological processes for the treatment of Cr(VI) industrial effluents by either pure culture or a consortium of Cr(VI)-reducing bacteria, with various degrees of success. Among issues to be considered include high cost of nutrient for the bacteria, low Cr resistant-reducing ability of environmental isolates, difficulty in scaling up finding in the laboratory to pilot scale and on-site application as well as the understanding on the dynamic underlying mechanisms for bacterial Cr(VI) reduction. This review highlights cytotoxicity and genotoxicity properties of Cr(VI), which form the biggest motivation for continuous development in the field of Cr(VI) treatment technologies, latest finding in aerobic and anaerobic bacterial reduction of Cr(VI), operational challenges for bacterial Cr(VI) reduction, and some examples for laboratory-scale and pilot-scale evaluation of free and immobilized (biofilm) cells of Cr(VI) resistant-reducing bacteria.

Selenium at high levels may cause adverse health effects on human beings and endanger aquatic lives due to its toxicity. Se(VI) reduction in continuous-flow reactors packed with Shigella fergusonii strain TB42616 immobilized by Ca2+-alginate gel beads was investigated under various hydraulic retention times (HRT) and influent Se(VI) concentrations. Removal efficiency up to 98.8 % was achieved after 96 days operation under an HRT of 5 days and an influent Se(VI) concentration of 400 mg/L. The results showed that the overall selenium removal efficiency was affected by the HRT and the bed height of the reactor but not the influent Se(VI) concentration. The steady-state data were analyzed using a mathematical model and Monod-type kinetics. Biokinetic parameters of half-velocity constants and maximum specific reduction rates were optimized using steady-state data obtained under a range of HRTs (0.73–5.0 days) at a constant influent Se(VI) concentration of 50 mg/L. The model was validated using steady-state data obtained under influent Se(VI) concentrations ranging from 10 to 400 mg/L while maintaining the HRT at 5.0 days. The high correlation coefficients between model calculated Se(VI) and Se(IV) concentrations and the experimental data indicate that the model is robust to predict the performance of the continuous-flow bioreactor.

The kinetics of Se(VI) reduction by a defined co-culture of a Se(VI)-reducing strain Shigella fergusonii TB42616 (TB) and a Se(IV)-reducing strain Pantoea vagans EWB32213-2 (EWB) was investigated in batch reactors. Se(VI) reduction was a two-stage process from Se(VI) to Se(IV) and then from Se(IV) to Se(0). Biokinetic parameters were optimized with a Monod-type kinetic model using batch pure culture data through the Robust Global Optimization Algorithm embedded in a computer package including yield coefficients, decay coefficients, maximum specific growth rates, and half-velocity constants. Se(VI) reduction by the defined co-culture was then simulated and verified over a range of culture compositions and initial Se(VI) concentrations, respectively. An inter-species inhibition term was incorporated into the model to illustrate the competition for Se(IV) between these two species during Se(VI) reduction in the co-culture. The results indicated that the incubation time corresponding to the peak level of Se(IV) increased with initial Se(VI) concentrations and a significant increase of Se(IV) accumulation with higher initial Se(VI) concentration. However, Se(IV) accumulation can be reduced with increasing population ratio of EWB to TB. The relatively high correlation coefficients suggested that the model was robust and applicable in simulating Se(VI) reduction by the defined co-culture.

Carbon and nitrogen stable isotopic ratios are increasingly used in sediment fingerprinting studies. However, questions remain regarding tracer conservativeness during sediment transport and other error considerations. We investigate conservativeness processes, including carbon oxidation and nitrogen mineralization, using experiments. We also test how other considerations impact the isotopic ratios including algae accrual into temporary sediment deposits in the river, the physical loss of organic matter via disaggregation, concentration dependent mixing, and time-varying isotopic ratios of sediment sources. Results show all processes and considerations can change isotope abundance, however, significance varied. Carbon oxidation, nitrogen mineralization and upland seasonality of sediment sources did not significantly change isotopic ratios. Algae accrual, concentration dependency mixing, physical loss of organic matter during transport, and seasonality of the in-stream sediment source significantly changed the isotopic ratios for the conditions tested. Fertilization significantly impacted the stable carbon isotopic ratio in one case considered. Results from sediment fingerprinting simulations and testing how well the virtual mixture fits the mass balance equation agreed with significance results for tracer changes, and some uncertainty considerations changed fractional contribution of sources by as much as 50%. A noteworthy recommendation is the mean isotopic ratios of sediment sources should be separated by at least 1‰ to lessen tracer conservativeness concerns in fingerprinting simulation. We recommend concentration dependent mixing becomes the accepted practice when using isotopic ratios, however, we warn against using particle size corrections. We recommend the loss of organic matter during disaggregation be accounted for in fingerprinting estimates. We recommend algae accrual in in-stream sediment deposits should either be accounted for or in-stream sediment should be treated as a time-varying source in sediment fingerprinting simulations. Finally, we recommend both the carbon and nitrogen isotopic ratio should be tested as potential tracers because the two tracers performed similarly when testing how well the virtual mixture fits the mass balance equations.

Selenium reduction was evaluated with pure batch cultures of Shigella fergusonii strain TB42616 (TB) and Pantoea vagans strain EWB32213-2 (EWB), respectively. A two-stage process, from Se(VI) to Se(IV) and then from Se(IV) to Se(0), was observed. The second stage of reduction, from Se(IV) to Se(0), was observed as the rate-limiting step resulting in accumulation of the more toxic Se(IV). In order to facilitate Se(VI) reduction and reduce Se(IV) accumulation, the Se(VI)-reducing strain TB was co-cultured with a Se(IV)-reducing strain EWB. Although Se(VI) reduction rate was not affected, Se(IV) reduction was significantly enhanced with low Se(IV) accumulation in the defined co-culture. Effects of culture composition as well as nitrate and arsenate on Se(VI) reduction were also investigated. A co-culture composition of 10:1 (EWB:TB) ratio was observed to achieve the best total selenium reduction. In addition, nitrate at 50 mg/L was observed to inhibit Se(IV) reduction but not Se(VI) reduction, while arsenate at 200 mg/L exhibited slight inhibition on both Se(VI) and Se(IV) reduction.

The unwanted light transmitting through the gap spaces of low fill factor lens array will deteriorate the signal contrast detected by the sensor. The high cost photolithographic techniques and optical coating technology have to be used to deposit a metallic film precisely filling these gap regions, which is only suitable for the lens array on flat substrate. In this paper, we will propose an efficient way for the fabrication of gap-masked lens array on a curved plastic substrate by using the direct diamond turning and spray coating process. The semi-finished lens array (SFLA) on a convex surface is first fabricated by rough cutting with fast tool servo. A paint film layer with mirror surface effect is then formed uniformly by spray coating on the SFLA which has a rotation speed controlled by the computer-numerically controlled (CNC) machine. At last, the lenslet surfaces are uncovered and regenerated by finishing cutting process. Without any reloading or re-position error, this cost-effective method can generate various gap-masked array optics on curved substrate with customized period and grid pattern.

Se(VI) and Se(IV) are the two major species of selenium in water. They are toxic to aquatic lives and human beings at high levels. Biological reduction of Se(VI) is a two-stage process, fir...

This study investigated the neural basis of social adjustment using multimodal brain imaging and social-adjustment measurements to analyze functional and structural brain features during social adjustment in college students. The results showed that, regarding brain function, some dimensions of social adjustment were associated with the insula, and some regions of the frontal and occipital lobes. Self-adjustment and satisfaction required activation of the middle frontal gyrus, while career adjustment and academic adjustment required inhibition of the inferior frontal gyrus and lingual gyrus, respectively. Decreased metabolic activity of the lingual gyrus was beneficial for obtaining satisfaction. Regarding brain structure, the total score and some dimensions of social adaptation were associated with the gray matter of portions of the temporal and parietal lobes. The superior temporal gyrus was associated with the total social adjustment and satisfaction score, the middle temporal gyrus with campus-life adjustment and satisfaction, and the post central gyrus and the inferior parietal lobule with emotional adjustment. The changes in the gray matter volume of these brain regions to a certain extent reflected socially adaptive behaviors. The results suggest that social adaptability is associated with various brain regions dispersed among both hemispheres of the brain, and requires synergistic inter-actions between multiple brain regions and both brain hemispheres.

Selenium removal by activated alumina (AA) in batch and continuous-flow reactors was investigated in this study. The adsorption kinetics fitted pseudo-first as well as pseudo-second order models with equilibrium time for Se(VI) and Se(IV) adsorption of 8 and 12 hr, respectively. A significant higher adsorption capacity for Se(IV) than Se(VI) was observed in isothermal adsorption experiments. The adsorption isotherms of Se(VI) and Se(IV) agreed well with both Langmuir and Freundlich adsorption models. The results also showed that Se(VI) adsorption was adversely affected by NaHCO3 concentrations, while Se(IV) adsorption was not due to the selectivity of activated alumina for anions. In the continuous-flow reactor packed with AA and inoculated with Shigella fergusonii strain TB42616 under a hydraulic detention time of 3 days, approximately 74% and 70% Se(VI) were removed after 40 days at influent concentrations of 10 and 50 mg/L, respectively. Effluent concentrations of Se(IV) from the bioreactor were insignificant due to the combination of bioactivities and adsorption. The AA-packed bioreactor is promising in both Se(VI) and Se(IV) removal as better removal efficiency may be accomplished by increasing the liquid retention time. PRACTITIONER POINTS: The adsorption capacity for Se(IV) of activated alumina was significantly higher than that for Se(VI). Se(VI) adsorption was inhibited by NaHCO3 , while Se(IV) adsorption was not. Se(IV) formed by biological Se(VI) reduction was adsorbed by activated alumina in continuous-flow reactors. Both Se(VI) and Se(IV) were significantly removed by activated alumina-packed continuous-flow reactors.

This article presents experimental characterization and numerical simulation techniques used to create large amplitude and high frequency surface waves with the help of a metal/ceramic composite transducer array. Four piezoelectric bimorph transducers are cascaded and operated in a nonlinear regime, creating broad band resonant vibrations. The used metallic plate itself resembles a movable wall which can align perfectly with an airfoil surface. A phase-shifted operation of the actuators results in local displacements that generate a surface wave in the boundary layer for an active turbulence control application. The primary focus of this article is actuator design and a systematic parameter variation experiment which helped optimize its nonlinear dynamics. Finite Element Model (FEM) simulations were performed for different design variants, with a primary focus in particular on the minimization of bending stress seen directly on the piezo elements while achieving the highest possible deflection of the vibrating metallic plate. Large output force and a small yield stress (leading to a relatively small output stoke) are characteristics intrinsic to the stiff piezo-ceramics. Optimized piezo thickness and its spatial distribution on the bending surface resulted in an efficient stress management within the bimorph design. Thus, our proposed resonant transduction array achieved surface vibrations with a maximum peak-to-peak amplitude of 500 μ m in a frequency range around 1200 Hz.

Batch studies on selenium reduction were conducted to assess the reduction rate of Se(VI) as well as Se(IV) using Escherichia coli Strain EWB32213 isolated in the laboratory. The rate of Se...

This article reports on the experimental design and optimization of a piezoelectric bimorph transducer array used to create large amplitude and high frequency vibrations at an airfoil surface demonstrating an active flow control strategy. Broad-band resonant surface vibrations are created with the help of a metal / ceramic composite actuator design which operates in a nonlinear regime. The array design comprises of a flat metallic surface plate which can align perfectly to an airfoil hence resembling a movable wall in a turbulent boundary layer. A phase shifted operation of the actuators results in local displacements that generate transverse surface waves in the turbulent boundary layer. Furthermore, the flow control functionality is validated by performing Particle Image Velocimetry (PIV) measurements in an atmospheric wind tunnel.

As a kind of cloud computing infrastructure, Hadoop has attracted more attention from a group of corporations and has been widely used. The framework and character of Hadoop were detailed introduced and analyzed as well as the application opportunities of Hadoop in the field of communication in the future were prospected in this paper. An application based on Hadoop was designed and experiment result demonstrates the efficiency of Hadoop on dealing with big dataset.

We use higher dimensional B-splines as basis functions to find the approximations for the Dirichlet problem of the Poisson equation in dimension two and three. We utilize the boundary data to remove unnecessary bases. Our method is applicable to more general linear partial differential equations. We provide new basis functions which do not require as many B-splines. The number of new bases coincides with that of the necessary knots. The reducing process uses the boundary conditions to redefine a basis without extra artificial assumptions on knots which are outside the domain. Therefore, more accuracy would be expected from our method. The approximation solutions satisfy the Poisson equation at each mesh point and are solved explicitly using tensor product of matrices. © 2013 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 393–405, 2014

BACKGROUND: To clearly identify specific species and subspecies of the Lactobacillus acidophilus group using phenotypic and genotypic (16S rDNA sequence analysis) techniques alone is difficult. The aim of this study was to use the recA gene for species discrimination in the L. acidophilus group, as well as to develop a species-specific primer and single nucleotide polymorphism primer based on the recA gene sequence for species and subspecies identification. RESULTS: The average sequence similarity for the recA gene among type strains was 80.0%, and most members of the L. acidophilus group could be clearly distinguished. The species-specific primer was designed according to the recA gene sequencing, which was employed for polymerase chain reaction with the template DNA of Lactobacillus strains. A single 231-bp species-specific band was found only in L. delbrueckii. A SNaPshot mini-sequencing assay using recA as a target gene was also developed. The specificity of the mini-sequencing assay was evaluated using 31 strains of L. delbrueckii species and was able to unambiguously discriminate strains belonging to the subspecies L. delbrueckii subsp. bulgaricus. CONCLUSION: The phylogenetic relationships of most strains in the L. acidophilus group can be resolved using recA gene sequencing, and a novel method to identify the species and subspecies of the L. delbrueckii and L. delbrueckii subsp. bulgaricus was developed by species-specific polymerase chain reaction combined with SNaPshot mini-sequencing. Copyright © 2012 Society of Chemical Industry

This study was carried out to provide a platform for the pre-clinical evaluation of anti-cancer properties of a unique CAM (complementary and alternative medicine) agent,Antrodia camphorataalcohol extract (ACAE), in a mouse model with the advantageous non-invasivein vivobioluminescence molecular imaging technology.In vitroanalyses on the proliferation, migration/invasion, cell cycle and apoptosis were performed on ACAE-treated non-small cell lung cancer cells, H441GL and control CGL1 cells.In vivo, immune-deficient mice were inoculated subcutaneously with H441GL followed by oral gavages of ACAE. The effect of ACAE on tumor progression was monitored by non-invasive bioluminescence imaging. The proliferation and migration/invasion of H441GL cells were inhibited by ACAE in a dose-dependent manner. In addition, ACAE induced cell cycle arrest at G0/G1 phase and apoptosis in H441GL cells as shown by flow cytometric analysis, Annexin-V immunoflourescence and DNA fragmentation.In vivobioluminescence imaging revealed that tumorigenesis was significantly retarded by oral treatment of ACAE in a dose-dependent fashion. Based on our experimental data, ACAE contains anti-cancer properties and could be considered as a potential CAM agent in future clinical evaluation.

It has been known that parasites developed sophisticated strategies to escape from the host immune assault. More recently, one strategy to induce immune evasion involved CD4(+)CD25(+) regulatory T cells (Tregs). Mice were infected with Schistosoma japonicum cercariae and then injected intraperitoneally with anti-CD25 monoclonal antibody (anti-CD25 mAb). The results showed that the percentages of CD4(+)CD25(+) Tregs in mice were expanded by S. japonicum infection, and it could be partially blocked by anti-CD25 mAb. Worm burden in anti-CD25 mAb group (23.17 ± 6.94) was significantly lower than that in infected group (30.17 ± 5.85). The level of interferon gamma was increased with anti-CD25 mAb administration; meanwhile, lower concentration of interleukin 10 was observed in the same group. These results suggest that CD4(+)CD25(+) Tregs contribute to the escape of S. japonicum from the host immune responses, while anti-CD25 mAb can partially block CD4(+)CD25(+) Tregs and enhance the protective immunity to the parasite by Th1-type immune response.

As(III) oxidation by a chemoautotrophic bacterium, Thiomonas arsenivorans strain b6, was evaluated in a continuous stirred tank reactor (CSTR) under a range of influent As(III) concentrations (2,000–4,000 mg/L) and hydraulic retention times (HRTs) (21.7–74.9 h). Five steady states were obtained after the CSTR was continuously operated for 115 days with over 99% As(III) oxidized under the optimal growth conditions for strain b6 at pH 6 and 30°C . The culture exhibited strong resilience by recovering from an As(III) overloading of 4,847.4±290.9 mg/day/L operated at a HRT of 21.7 h. Arsenic mass balance analysis revealed that As(III) was mainly oxidized to As(V), with unaccounted arsenic well within the analytical error of measurement. The best estimates of biokinetic parameters for As(III) oxidation were obtained using the steady-state data and the Monod expression based model [ k=5 mg As(III)/mg dry cell weight/h; Ks =20.1 mg/L ; kd =0.008 h−1 ; and Y=0.011 mg cell dry weight/mg As(III)]. The Monod model ...

Arsenite [As(III)] oxidation by Thiomonas arsenivorans Strain b6 was investigated in batch reactors at pH 6 and 30°C over As(III) concentrations ranging from 10 to 1,000 mg/L in the absence of added organic carbon. Strain b6 completely oxidized As(III) to arsenate [As(V)] during exponential growth phase for lower levels of As(III) concentrations ( ≤100 mg/L ) . At higher levels of 500 and 1,000 mg/L, As(III) oxidation was observed mostly in the exponential phase but continued into the stationary phase of growth. The Haldane substrate inhibition model was used to estimate biokinetic parameters for As(III) oxidation. The best fit parameters of half saturation constant Ks =33.2±1.87 mg/L , maximum specific substrate utilization rate k= ( 0.85±0.18 ) -mg As(III)/mg dry cell weight/h, substrate inhibition coefficient Ki =602.4±33.6 mg/L , yield coefficient Y= ( 0.088±0.0048 ) -mg cell dry weight/mg As(III), and endogenous decay coefficient kd =0.006±0.002 h−1 were obtained using the Adams-Bashforth-Moulton al...

The temperature-dependent oxidation of Pt nanoclusters on a thin film of Al 2 O 3 on NiA1(100), in the absence of a gaseous oxidizing agent, was investigated with various surface probe techniques. The Pt clusters (of mean diameter 2.2 nm and height 0.4 nm) grown from vapor deposition on the thin film of Al 2 O 3 on NiA1(100) at 300 K became partially oxidized, as charge transfer from the Pt clusters to the oxide was indicated by a significant negative shift (0.4-0.5 eV) of binding energy (BE) of AI ox 2p and O Is states from Al 2 O 3 . The oxidation of the cluster proceeded to a further level when the sample was annealed above 450 K; the Pt 4f 7/2 core level moved positively from BE 72.0 eV with increasing annealing temperature and eventually attained 72.6 eV above 650 K, which indicates a state of Pt 2+ . Accompanying this further oxidation, signals of both AI ox 2p and O Is shifted back to greater BE. The valence spectra indicate that the Pt-Al 2 O 3 interaction was sustained whereas a new Pt-O bond was formed. Formation of a Pt x Al y O z complex is proposed to explain the observations. The new Pt oxide binding was substantially stronger than the initial one, as was evident from the oxidized clusters being resistant to sintering induced in electrochemical processes. The oxidation was associated also with a migration of oxide materials onto the Pt clusters, as both Al 2 O 3 (100) and NiAl(001) facets roughened after the annealing, and a probe of methanol adsorption showed no bare Pt clusters exposed but alumina-like structures on the surface.

Arsenic(III) oxidation was evaluated in a continuous-flow fluidized-bed reactor (FBR) with Alcaligenes faecalis strain 01201 immobilized in gel beads. The FBR was operated under 300 mg/L citrate and a range of influent As(III) concentrations (75 to 3000 mg/L) at short hydraulic retention times (1.06 to 3.17 hours). The pH and temperature in the FBR were maintained at optimal growth conditions for strain O1201 (pH 7 and 30 degrees C) throughout the study. A total of 10 quasi-steady-state operating conditions were obtained after 54 days of operation under an As(III) concentration of 441 mg/L (10 000 mg/L/d loading rate), with As (III) removal efficiency ranging from 76% to near complete. Material balance analysis over the FBR revealed that the difference between the cumulative influent As (III) and the sum of cumulative effluent As(III) and As(V) was insignificant. The major mechanism of As(III) removal from the FBR is biological oxidation to As(V).

As(III) oxidation by a pure bacterial culture, Alcaligenes faecalis strain O1201, was evaluated using a continuous stirred tank reactor. The bioreactor system was operated for 204 days under a wide range of influent As(III) concentrations (500–8,000 mg∕L) and hydraulic retention times (25.6–90.7 h) with citrate as the sole carbon and energy source at pH 7 and 30°C. Nine steady-state conditions were obtained with As(III) oxidation efficiency exceeding 95%. The system quickly recovered from an As(III) overloading at 15,000 mg∕day∕L while it operated at a HRT of 12.8 h . A material balance analysis revealed that nearly all the As(III) removed in the continuous stirred tank reactor (CSTR) was oxidized to As(V) and only 3.2% of the As(III) fed to the CSTR was unaccounted for. Biokinetic parameters, kmc =0.86 mg∕mg cell dry weight/h and Kc =70 mg∕L , for As(III) oxidation were obtained using the Monod expression and data obtained at steady-state conditions.

In this study, the annealed effect (at 150 °C ∼ 250 °C for 1 h) on the tensile mechanical properties of thin copper wires with φ = 25 μm (1 mil) was investigated. The microstructural characteristics and the mechanical properties before and after an electric flame-off (EFO) were also studied. Results indicate that with annealing temperatures of more than 200 °C, the wires possessed a fully annealed structure, the tensile strength and the hardness decreased, and the elongation was raised significantly. Through recrystallization, equiaxed grains and a few annealed twins formed in the matrix structure. The microstructures of the free air ball (FAB) of the various wires after EFO contained column-like grains. The column-like grains grew from the heat-affected zone (HAZ) to the Cu ball, and the preferred orientation was . According to Weibull’s reliability analysis, the failure rates of all the specimens were the modus of wear-failure. The tensile strength and the reliability of both the 200 °C and 250 °C annealed wires in the HAZs showed the highest values of all.

Manganese(II) oxidation by a new bacterium isolate, Pseudomonas putida strain EC112, was studied in batch reactors over a range of Mn(II) concentrations (1–26 mg/L) in a chemically defined liquid medium (at pH 6.5 and 30°C). Bacterial Mn(II) oxidation initiated after the exponential growth phase and carbon source consumption. The best fit kinetic oxidation parameters of half-saturation coefficient Ks=1.086±0.029 mg/L and maximum specific substrate utilization rate constant k=0.180±0.003 mg Mn(II)/(mg dry cell mass·h) were obtained using Monod-type kinetics and fitted with the Levenberg-Marquardt nonlinear least-squared algorithm. Additional experiments assessed the potential of Mn(II) oxidation by strain EC112 in the presence of the oxidation products of humic acid (HA) and manganese dioxide (MnO2). Results show enhanced biological Mn oxidation and growth. This suggests MnO2 oxidizes biologically refractory organic matter to substrates that support microorganism growth.

A new species, Pythiogeton zizaniae, was isolated from diseased water bamboo (Zizania latifo- lia) in central Taiwan. The organism formed a colony with scanty mycelia and mycelial aggregates on rye- water bamboo medium. Special treatments were required for production of sporangia which were terminal, noncaducous and mostly ovoid. Chlamydo- spores were absent. The fungus was homothallic. Oogonia produced on V-8 water bamboo medium in water were mostly globose to subglobose and each was attached with a club-shaped, monoclinous antherid- ium by the base of the oogonium stalk. Oospores were plerotic and globose to subglobose. Py. zizaniae caused death of water bamboo suckers but did not infect seedlings of corn, rice, wheat, sorghum, cucumber, tomato, soybean or water spinach. It also did not affect cucumber and tomato fruit, carrot roots or potato tubers.

Compared with gold wire, copper wire is cheaper and possesses lower cost, greater strength and better electrical conductivity, and therefore is becoming more commonly used. But the lower ductility and oxidation undermine the reliability of copper wire bonding, making the wire susceptible to breaking. In the present study, the annealed effect (at 150-250°C for 1 hour) on the tensile mechanical properties of copper wires with Φ = 25μm (1 mil) was investigated. In addition, the microstructural characteristics and the mechanical properties before and after an electric flame-off (EFO) process were also studied. Experimental results indicate that with annealing temperatures of more than 200°C, the copper wires possessed a fully annealed structure, the tensile strength and the hardness decreased, and the elongation was raised significantly. Through recrystallization, the matrix structure transferred from long, thin grains to equiaxed grains and a few annealed twins. The microstructures of the free air ball (FAB) of the variation annealing wires after an EFO process were column-like grains. The column-like grains grew from the heat-affected zone (HAZ) to the Cu ball, and the preferred orientation was (100). Under the thermal effect of EFO, the necks of the Cu balls underwent recrystallization and the grain growth was induced. Additionally, the decreased hardness and the strength of the HAZ resulted in the breakage sites of the EFO wires being in the HAZ near the Cu balls.

A transient-state model was developed to simulate simultaneous Cr(VI) reduction and phenol degradation by a coculture of Cr(VI)-reducing/phenol-degrading bacteria growing on glass bead surfaces in a fixed-film bioreactor. The coculture consisted of the Cr(VI) reducers, Escherichia coli ATCC 33456, and the phenol degraders, Pseudomonas putida DMP-1. Phenol was supplied as the sole added carbon source and electron donor. The model simulated cell growth kinetics with E. coli utilizing metabolites formed from phenol degradation in P. putida as carbon sources. Substrate utilization and Cr(VI) reduction in the fixed-film bioreactor was represented by a system of (second-order) partial differential equations (PDEs). The PDE system was solved by the fourth-order Runge–Kutta method adjusted for mass transport resistance by the second-order Crank–Nicholson and backward Euler methods. A heuristic procedure, genetic search algorithm, was used to optimize the model against experimental data. The model predicted efflue...

Batch experiments were conducted to examine the oxidation of arsenite (As (III)) to arsenate (As (V)) by Alcaligenes faecalis strain O1201 isolated from soils. Pure cultures of O1201 completely oxidized As (III) to As (V) in the exponential growth phase at As (III) concentrations ranging from 10 to 1,000 mg∕L in less than 12 h. The growth of O1201 requires an organic substrate as the carbon and energy source, and the oxidation of As (III) was mainly observed in the exponential growth phase. As (III) concentration at 500 mg∕L inhibited the growth of O1201, whereas its oxidation product As (V) did not show any inhibition effects even at concentration as high as 1,000 mg∕L . Kinetics studies of As (III) oxidation were performed under the optimal conditions for O1201 at pH 7 and 30°C in a chemical defined medium with citrate as the sole carbon source. The Monod expression coupled with a logistic growth model was used to analyze the kinetics of As (III) oxidation. The best fit parameters of half-velocity coeff...

Chromium is one of the most widely used metals in industry. In addition, trivalent chromium( Cr(III)), is an essential trace element necessary for glucose and lipid metabolism and for the utilization of amino acids. Current treatment techniques for chromium-containing wastes generally involve aqueous reduction of hexavalent chromium (Cr(VI)) to Cr(III) by using a reducing agent at lowered pH with subsequent adjustment of the solution pH to near-neutral ranges to precipitate the less soluble Cr(III). Many facultative anaerobes are capable of reducing Cr(VI) to Cr(III) under appropriate conditions. Chromium-reducing bacteria may utilize a variety of organic compounds as electron donors for chromium reduction. The toxicity of Cr(VI) toward Cr(VI) reduction may be illustrated by the finite capacity of cells. The ability of an enzyme-based kinetic model to analyze Cr(VI) reduction was further demonstrated with two other strains, D. vulgaris and P. ambigua, reported in the literature. The model illustrates an important characteristic of microbial Cr(VI) reduction. The electron donors known for Cr(VI) reduction are generally limited to nontoxic aliphatic compounds, mainly low-molecular-weight carbohydrates, amino acids, and fatty acids. Recent work has revealed the potential of using Cr(VI)-reducing microorganisms for detoxifying Cr(VI)-contaminated environments or for treating Cr(VI)-containing wastes, even if the biochemical mechanisms of Cr(VI) reduction are not yet fully understood. Recent success in using a biofilm reactor for continuous reduction of Cr(VI) may have shed some light on methods for the biological treatment of Cr(VI)-containing wastes.

Flexible flow shops can be thought of as generalizations of simple flow shops. In the past, the processing time for each job was usually assumed to be known exactly, but in many real-world applications, processing times may vary dynamically due to human factors or operating faults. In T.P. Hong, W.C. Chen [Journal of Advanced Computing Intelligence 2 (4) (1998) 142–149], we have demonstrated how discrete fuzzy concepts could easily be used in the Sriskandarajah and Sethi's algorithm for managing uncertain flexible-flow-shop scheduling. In this paper, we generalize it to continuous fuzzy domains. We use triangular membership functions for flexible flow shops with two machine centers to examine processing-time uncertainties and to make scheduling more suitable for real applications. We first use triangular fuzzy LPT algorithm to allocate jobs, and then use triangular fuzzy Johnson algorithm to deal with sequencing the tasks. The proposed method thus provides a more flexible way of scheduling jobs than conventional scheduling methods.