Screening of <Emphasis Type="Italic">Isochrysis</Emphasis> Strains and Utilization of a Two-Stage Outdoor Cultivation Strategy for Algal Biomass and Lipid Production

Isochrysis is a genus of marine algae without cell wall and capable of accumulating lipids. In this study, the lipid production potential of Isochrysis was assessed by comparing 15 Isochrysis strains with respect to their growth rate, lipid production, and fatty acid profiles. Three best strains were selected (lipid productivity, 103.0~121.7 mg L^?1 day^?1) and their lipid-producing capacities were further examined under different controlled parameters, e.g., growth phase, medium nutrient, and light intensity in laboratory cultures. Furthermore, the three Isochrysis strains were monitored in outdoor panel photobioreactors with various initial cell densities and optical paths, and the strain CS177 demonstrated the superior potential for outdoor cultivation. A two-stage semi-continuous strategy for CS177 was subsequently developed, where high productivities of biomass (1.1 g L^?1 day^?1) and lipid (0.35 g L^?1 day^?1) were achieved. This is a comprehensive study to evaluate the lipid-producing capability of Isochrysis strains under both indoor and outdoor conditions. Results of the present work lay a solid foundation for the physiological and biochemical responses of Isochrysis to various conditions, shedding light on the future utilization of this cell wall-lacking marine alga for biofuel production.     

Enzymatic Hydrolysis of Black Liquor Xylan by a Novel Xylose-Tolerant,Thermostable β-Xylosidase from a Tropical Strain of <Emphasis Type="Italic">Aureobasidium pullulans</Emphasis> CBS 135684

From three cell-associated β-xylosidases produced by Aureobasidium pullulans CBS 135684, the principal enzyme was enriched to apparent homogeneity and found to be active at high temperatures (60–70 °C) over a pH range of 5–9 with a specific activity of 163.3 units (U) mg^?1. The enzyme was thermostable, retaining over 80% of its initial activity after a 12-h incubation at 60 °C, with half-lives of 38, 22, and 10 h at 60, 65, and 70 °C, respectively. Moreover, it was tolerant to xylose inhibition with a K _i value of 18 mM. The K _m and V _max values against p-nitrophenyl-β-d-xylopyranoside were 5.57 ± 0.27 mM and 137.0 ± 4.8 μmol min^?1 mg^?1 protein, respectively. When combining this β-xylosidase with xylanase from the same A. pullulans strain, the rate of black liquor xylan hydrolysis was significantly improved by up to 1.6-fold. The maximum xylose yield (0.812 ± 0.015 g g^?1 dry weight) was obtained from a reaction mixture containing 10% (w/v) black liquor xylan, 6 U g^?1 β-xylosidase and 16 U g^?1 xylanase after incubation for 4 h at 70 °C and pH 6.0.     

Application of Physicochemical Treatment Allows Reutilization of <Emphasis Type="Italic">Arthrospira platensis</Emphasis> Exhausted Medium

Since cultivations of Arthrospira platensis have a high water demand, it is necessary to develop treatment methods for reusing the exhausted medium that may prevent environmental problems and obtaining useful biomass. The exhausted Schlösser medium obtained from A. platensis batch cultivation in bench-scale mini-tanks was treated by varying concentrations of different coagulants, ferric chloride (6, 10, and 14 mg L^?1) or ferric sulfate (15, 25, and 35 mg L^?1) and powdered activated carbon (PAC, 30 and 50 mg L^?1). Such treated effluent was restored with NaNO₃ and reused in new cultivations of A. platensis performed in Erlenmeyer flasks. Reusing media through the cultivation of A. platensis showed satisfactory results, particularly in the medium treated with ferric chloride and PAC. The maximum cell concentration obtained in the flasks was 1093 mg L^?1, which corresponded to the medium treated with ferric chloride (6 mg L^?1) and PAC (30 mg L^?1). This cellular growth was higher than in the medium treated with ferric sulfate and PAC, in which values of maximum cell concentration did not exceed 796 mg L^?1. The cultures in the media after treatment did not modify the biomass composition. Thus, combined coagulation/adsorption processes, commonly used in water treatment processes, can be efficient and viable for treating exhausted medium of A. platensis, allowing the production of such biomass with the reduction of production cost and saving water.     

Production of <Emphasis Type="Italic">R</Emphasis>-Mandelic Acid Using Nitrilase from Recombinant <Emphasis Type="Italic">E. coli</Emphasis> Cells Immobilized with Tris(Hydroxymethyl)Phosphine

Recombinant Escherichia coli cells harboring nitrilase from Alcaligenes faecalis were immobilized using tris(hydroxymethyl)phosphine (THP) as the coupling agent. The optimal pH and temperature of the THP-immobilized cells were determined at pH 8.0 and 55 °C. The half-lives of THP-immobilized cells measured at 35, 40, and 50 °C were 1800, 965, and 163 h, respectively. The concentration of R-mandelic acid (R-MA) reached 358 mM after merely 1-h conversion by the immobilized cells with 500 mM R,S-mandelonitrile (R,S-MN), affording the highest productivity of 1307 g L^?1 day^?1 and the space-time productivity of 143.2 mmol L^?1 h^?1 g^?1. The immobilized cells with granular shape were successfully recycled for 60 batches using 100 mM R,S-MN as substrate at 40 °C with 64% of relative activity, suggesting that the immobilized E. coli cells obtained in this study are promising for the production of R-MA.     

High-efficiency enrichment of uranium(VI) from aqueous solution by hydromagnesite and its calcination products

The removal of uranium from aqueous solution by hydromagnesite and its calcination products was investigated. Through the study, we found that the adsorption capacities of hydromagnesite, magnesium carbonate and magnesium oxide for uranium could reach 342.96, 493.79, 2154.14 mg g^?1, respectively. The high temperature will reduce the activity of magnesium oxide, resulting in the adsorption capacity decrease. The results indicate that the optimum pH for the heat-treated samples was 3.0–4.5 and for hydromagnesite 6.0–7.0. Thermodynamic parameters such as ?G, ?H and ?S, indicated that the adsorption processes are spontaneous and endothermic.     

Growth Parameters,Photosynthetic Performance,and Biochemical Characterization of Newly Isolated Green Microalgae in Response to Culture Condition Variations

This work aimed to characterize two native microalgal strains newly isolated from South Mediterranean areas and identified as Chlorella sorokiniana ES3 and Neochloris sp. AM2. The growth properties and biochemical composition of these microalgae were evaluated in different culture media (Algal, BG-11, f/2, and Conway). Among the tested media, nitrate- and phosphate-rich Algal medium provided the maximum biomass productivities (85.5 and 111.5 mg l^?1 day^?1 for C. sorokiniana and Neochloris sp., respectively), while the nitrate- and phosphate-deficient f/2 medium resulted in the highest lipid productivities (24.1 and 35.8 mg l^?1 day^?1 for C. sorokiniana and Neochloris sp., respectively). The physiological state of both microalgae was investigated under different light and temperature levels using the pulse amplitude-modulated fluorometry. The better photosynthetic efficiency of C. sorokiniana was obtained at 23 °C with a light saturation of 156 μE m^?2 s^?1, while that of Neochloris sp. was achieved at 15 °C with a light saturation of 151 μE m^?2 s^?1. The analysis of fatty acid profile and biodiesel parameters revealed that C. sorokiniana, cultivated in Algal and f/2 media, can be considered as a suitable candidate for high-quality biodiesel production.     

Bamboo (<Emphasis Type="Italic">Phyllostachys pubescens</Emphasis>) as a Natural Support for Neutral Protease Immobilization

Lignin polymers in bamboo (Phyllostachys pubescens) were decomposed into polyphenols at high temperatures and oxidized for the introduction of quinone groups from peroxidase extracted from bamboo shoots and catalysis of UV. According to the results of FT-IR spectra analysis, neutral proteases (NPs) can be immobilized on the oxidized lignin by covalent bonding formed by amine group and quinone group. The optimum condition for the immobilization of NPs on the bamboo bar was obtained at pH 7.0, 40 °C, and duration of 4 h; the amount of immobilized enzyme was up to 5 mg g^?1 bamboo bar. The optimal pH for both free NP (FNP) and INP was approximately 7.0, and the maximum activity of INP was determined at 60 °C, whereas FNP presented maximum activity at 50 °C. The K_m values of INP and FNP were determined as 0.773 and 0.843 mg ml^?1, respectively; INP showed a lower K_m value and V_max, than FNP, which demonstrated that INP presented higher affinity to substrate. Compared to FNP, INP showed broader thermal and storage stability under the same trial condition. With respect to cost, INP presented considerable recycling efficiency for up to six consecutive cycles.     

Treatment of chromium effluent by adsorption on chitosan activated with ionic liquids

This study proposes, verifies, and refines the use of biopolymers treated with two new ionic liquids (ILs) (sec-butylammonium acetate and n-octylammonium acetate), as a platform for chromium adsorption. The ILs were synthesized, characterized, and applied to chitosan treatment. Analyzing the size distribution of microparticles of chitosan and chitosan activated with ILs (sec-butylammonium acetate and n-octylammonium acetate), we observed that a little decrease in the particle size occurred with the activation of chitosan (176 ± 0.02 μm to 167 ± 0.054 and 168.5 ± 0.05 μm, respectively), as well as changes in the X-ray diffraction FTIR_ATR spectra. Further studies were performed using the best adsorbent – chitosan treated with sec-butylammonium acetate. In this case, the chromium VI concentration in the sample was reduced by more than 99% when using chitosan treated with IL sec-butylammonium acetate. The best reaction time was determined as 1 h, which allowed a chromium adsorption of 99.1% and the adsorption kinetic data were best represented by the second-order model (k₂ = 11.7258 g mg^?1 min^?1). The maximum adsorption capacity was obtained using the Langmuir isotherm model (20.833 mg g^?1 at pH 4 during 1 h, using 1.0 g of chitosan), and the adsorption efficiency was enhanced at 25 °C by the Freundlich isotherm model, in which the constants KF and n were determined as 0.875 mg L^?1 and 1.610, respectively.     

Dye removal using 4A-zeolite/polyvinyl alcohol mixed matrix membrane adsorbents: preparation,characterization, adsorption,kinetics, and thermodynamics

In pursuit of improving performance of the methylene blue adsorption process, the potential of a novel 4A-zeolite/polyvinyl alcohol (PVA) membrane adsorbent was investigated. Adding 4A-zeolite particles to the PVA membrane adsorbent provided an effective structure for the adsorptive membrane in dye removal processes. Effect of zeolite content was also studied via synthesis of different mixed matrix membrane adsorbents (MMMAs) with 5, 10, 15, and 20 wt% 4A-zeolite content. Morphology of MMMAs was analyzed by scanning electron microscope and the intermolecular interactions were determined by Fourier transform infrared spectroscopy. X-ray diffraction was performed to determine the crystal structure of MMMAs. For the sake of finding optimum condition, the adsorption capacity was examined at various operating parameters, such as contact time, temperature, pH, and initial concentration. The maximum value of the adsorption capacity (q _e) of 41.08 mg g^?1 and the highest removal efficiency of 87.41 % were obtained by applying 20 wt% loading of 4A-zeolite. The experimental data were fitted well with the Freundlich adsorption isotherm model (R ² = 0.9917) compared with the Langmuir (R ² = 0.9489) and the Tempkin (R ² = 0.8886) adsorption isotherm models, and the adsorption kinetic data verified the best fitting with the pseudo-second-order model (R ² = 0.9999). The estimated data for Gibb’s free energy (ΔG°) showed that the adsorption process is spontaneous at lower temperature values and non-spontaneous at higher temperature values. Other evaluated thermodynamic parameters such as changing in enthalpy (ΔH°) and entropy (ΔS°) revealed that the adsorption process is exothermic with an increase in orderliness at the solid/solution interface.     

Structure and dynamics of a free aquaporin (AQP1) by a coarse-grained Monte Carlo simulation

Structure and dynamics of a free aquaporin (AQP1) are studied by a coarse-grained Monte Carlo simulation as a function of temperature using a phenomenological potential with the input of a knowledge-based residue–residue interaction. Response of the radius of gyration (R _g) of the protein to the temperature (T) is found to be nonlinear: Decay of R _g at T ≤ T _c is followed by a continuous increase at T ≥ T _c before reaching its saturation. In thermo-responsive regime, the protein exhibits segmental globularization with the persistence of three regions along its sequence involving residues ¹M–²⁵V and ²⁵⁰V–²⁶⁹K toward the beginning and end segments with a narrow intermediate region around ¹⁵⁵A–¹⁶³D. A detail analysis of the structure factor S(q) shows a global random coil conformation at high temperatures with an effective dimension D _e ~ 1.74 and a globular structure (D _e ~ 3) at low temperatures. In thermo-responsive regime, the variation of S(q) with the wave vector q reveals a systematic redistribution of self-organizing residues (in globular and fibrous sections) that depends on the length scale and the temperature.     

Enhanced Harvesting of <Emphasis Type="Italic">Chlorella vulgaris</Emphasis> Using Combined Flocculants

In this study, a novel flocculation strategy for harvesting Chlorella vulgaris with combined flocculants, poly (γ-glutamic acid) (γ-PGA) and calcium oxide (CaO), has been developed. The effect of flocculant dosage, the order of flocculant addition, mixing speed, and growth stage on the harvesting efficiency was evaluated. Results showed that the flocculation using combined flocculants significantly decreases the flocculant dosage and settling time compared with control. It was also found that CaO and γ-PGA influenced microalgal flocculation by changing the zeta potential of cells and pH of microalgal suspension. The most suitable order of flocculant addition was CaO first and then γ-PGA. The optimal mixing speed was 200 rpm for 0.5 min, followed by 50 rpm for another 4.5 min for CaO and γ-PGA with the highest flocculation efficiency of 95 % and a concentration factor of 35.5. The biomass concentration and lipid yield of the culture reusing the flocculated medium were similar to those when a fresh medium was used. Overall, the proposed method requires low energy input, alleviates biomass and water contamination, and reduces utilization of water resources and is feasible for harvesting C. vulgaris for biofuel and other bio-based chemical production.     

Bioaccumulation of <Superscript>137</Superscript>Cs and <Superscript>60</Superscript>Co by bacteria isolated from spent nuclear fuel pools

This paper is focused on a characterization of bacterial contamination in pool water of the interim spent fuel storage (JAVYS Inc.) in Slovak Republic and on bioaccumulation of ¹³⁷Cs and ⁶⁰Co by isolated bacteria. Bacterial community in pool water is kept on very low level by extremely low concentration of solutes in deionized water and by the efficient water filtration system. Based on standard methods and sequencing of 16S rDNA four pure bacterial cultures were identified as Kocuria palustris, Micrococcus luteus, Ochrobactrum spp. and Pseudomonas aeruginosa. Isolated aerobic bacteria were able to bioaccumulate ¹³⁷Cs and ⁶⁰Co in laboratory experiments. The mechanism of Co and Cs binding involve rapid interactions with anionic groups of the components of cell surface and in the case of Cs⁺ ions is followed by transport processes across cytoplasm membranes and by intracellular distribution. The maximum specific uptake of Cs⁺ after 48 h cultivation in mineral medium (MM) reached 7.54 ± 0.48 μmol g^?1 dw (Ochrobactrum spp.), 19.6 ± 0.1 μmol g^?1 dw (M. luteus) and 20.1 ± 2.2 μmol g^?1 dw (K. palustris). The maximum specific uptake of Co²⁺ after 24 h cultivation in MM reached 31.1 ± 3.5 μmol g^?1 dw (Ochrobactrum spp.), 86.6 ± 12.2 μmol g^?1 dw (M. luteus) and 16.9 ± 1.2 μmol g^?1 dw (K. palustris). These results suggest that due to the long lasting uptake of ¹³⁷Cs, ⁶⁰Co and other radionuclides by biofilm in pool water high specific radioactivities (Bq m^?2) can be expected on stainless steel walls of pools.     

Function Analysis of Caffeoyl-CoA O-Methyltransferase for Biosynthesis of Lignin and Phenolic Acid in <Emphasis Type="Italic">Salvia miltiorrhiza</Emphasis>

In this study, we cloned a full-length cDNA and the genomic DNA sequence of SmCCoAOMT (GenBank ID JQ007585) from Salvia miltiorrhiza. The 744-bp open-reading frame encodes a protein of 247 amino acids that shares 95 % similarity with one in Vitis vinifera. Real-time quantitative PCR analysis revealed that SmCCoAOMT is most highly expressed in the stems and can be induced by methyl jasmonate (MeJA) and XC-1 treatment. To evaluate its function in vivo, we generated RNA interference transgenic plants through Agrobacterium tumefaciens-mediated gene transfer. Compared with untransformed control plants, the transgenics had significantly less lignin and the expression of lignin-biosynthetic genes SmCCR and SmCOMT was depressed. In 90-day-old roots from plants of transgenic line M5, accumulations of rosmarinic acid and salvianolic acid B (Sal B) were greatly reduced by 0.89- and 0.69-fold, respectively. This low-Sal B phenotype was stable in the roots, with the level of accumulation being approximately 43.58 mg g^?1 dry weight, which was 52 % of the amount measured in the untransformed control. Our results suggest that SmCCoAOMT is involved in lignin biosynthesis and affects the accumulation of phenolic acids. This study also provides potential guidance for using lignin-related genes to genetically engineer Salvia miltiorrhiza.     

Sorption separation of Eu and As from single-component systems by Fe-modified biochar: kinetic and equilibrium study

The utilization of carbonaceous materials in separation processes of radionuclides, heavy metals and metalloids represents a burning issue in environmental and waste management. The main objective of this study was to characterize the effect of chemical modification of corncob-derived biochar by Fe-impregnations on sorption efficiency of Eu and As as a model compounds of cationic lanthanides and anionic metalloids. The biochar sample produced in slow pyrolysis process at 500 °C before (BC) and after (IBC) impregnation process was characterized by elemental, FTIR, SEM-EDX analysis to confirm the effectiveness of Fe-impregnation process. The basic physico-chemical properties showed differences in surface area and pH values of BC- and IBC-derived sorbents. Sorption processes of Eu and As by BC and IBC were characterized as a time- and initial concentration of sorbate-dependent processes. The sorption equilibrium was reached for both sorbates in 24 h of contact time. Batch equilibrium experiments revealed the increased maximum sorption capacities (Q _max) of IBC for As about more than 20 times (Q _max BC 0.11 and Q _max IBC 2.26 mg g^?1). Our study confirmed negligible effect of Fe-impregnation on sorption capacity of biochar for Eu (Q _max BC 0.89 and Q _max IBC 0.98 mg g^?1). The iron-impregnation of biochar-derived sorbents can be utilized as a valuable treatment method to produce stable and more effective sorption materials for various xenobiotics separation from liquid wastes and aqueous solutions.     

Modeling of fixed-bed column studies for removal of cobalt ions from aqueous solution using <Emphasis Type="Italic">Chrysanthemum indicum</Emphasis>

The present study investigates the adsorption capability of raw and biochar forms of Chrysanthemum indicum flowers biomass to remove cobalt ions from aqueous solution in a fixed-bed column. Column adsorption experiments were conducted by varying the bed height (1.0, 2.0, 3.0 cm), flow rate (1.0, 2.5, 5.0 mL min^?1) and initial cobalt ion concentration (25, 50, 75 mg L^?1) to obtain the experimental breakthrough curves. The adsorption capacity of the raw and biochar forms of C. indicum flowers were found to be 14.84 and 28.34 mg g^?1, respectively, for an initial ion concentration of 50 mg L^?1 at 1.0 cm bed height and 1.0 mL min^?1 flow rate for Co (II) ion adsorption. Adam–Bohart, Thomas and Yoon–Nelson models were applied to the experimental column data to analyze the column performance. The Thomas model was found to best represent the column data with the predicted and experimental uptake capacity values correlating well and with higher R ² values for all the varying process parameters. Desorption studies revealed the suitability of the adsorbents for repeated use up to four adsorption–desorption cycles without significant loss in its efficiency. It can thus be inferred from the fixed-bed column studies that C. indicum flowers can suitably be used as an effective adsorbent for Co (II) ion removal from aqueous solution on a higher scale.     

Density,Viscosity, and Glass Transition of an Ethylenediamine–Ethylene Glycol Binary System

Densities ρ and viscosities η were measured for the binary mixtures of ethylenediamine (EDA) and ethylene glycol (EG) in the temperature range 288.15–323.15 K for ρ and at 273.15–323.15 K for η, both of which are broader temperature ranges than those reported previously. The value of ρ monotonously decreases against the mole fraction of EDA, x _EDA, and increasing temperature. The concentration dependence of η exhibits a maximum in the intermediate concentration range at all temperatures measured. The glass transition temperature, T _g, for samples with x _EDA < 0.7 was measured using differential scanning calorimetry. The measured T _g values show a peak in the intermediate concentration range, which is a behavior similar to that of η; however, the peak concentrations for η and T _g did not precisely align because of a deviation in the maximum hydrogen-bond density. The partial molar volumes for EDA and EG and the thermal expansivities, α, were obtained from ρ. Results in the present study are discussed in terms of the extensively increasing hydrogen-bond density for polyamine–polyhydric alcohol systems.     

One-step preparation of sulfonated carbon and subsequent preparation of hybrid material with polyaniline salt: a promising supercapacitor electrode material

The present trend to increase the energy density of electrochemical supercapacitor is to hybrid the electrochemical double layer capacitance electrode materials of carbon with loading or encapsulation of transition metal oxide or conductive polymeric pseudocapacitor materials as the binary or ternary hybrid electrochemical active materials. In this work, we selected polyaniline salt-sulfonated carbon hybrid (PANI-SA?C _SA ) as a cheaper electrode material for supercapacitor electrode. Sulfonated carbon (C _SA ) was prepared from hydrothermal carbonization of furaldehyde and p-toluenesulfonic acid. Polyaniline-sulfate salt containing sulfonated carbon was prepared by chemical oxidative polymerization of aniline using ammonium persulfate in presence of sulfuric acid and sulfonated carbon via aqueous, emulsion and interfacial polymerization pathways. Formation of hybrid material was confirmed from scanning electron microscopy. Among the hybrid prepared with three different polymerization pathways, hybrid prepared by aqueous polymerization pathway showed better electrochemical performance. The specific capacitance of the hybrid prepared via aqueous polymerization was 600 F g^?1, which is higher than that of the pristine PANI-SA (350 F g^?1) and C _SA (30 F g^?1). Hybrid material was subjected for 8000 charge-discharge cycles and at 8000 cycles; it showed 88% retention of its original specific capacitance value of 485 F g^?1 with coulombic efficiency (97–100%). These results showed that C _SA micro spheres prevent the degradation of PANI-SA chains during charge/discharge cycles. Specific capacitance, cycle life, low solution resistance, low charge transfer resistance and high phase angle value of PANI-SA?C _SA supercapacitor cell indicates a higher performance supercapacitor system.

Open image in new window

Graphical abstract Synthesis of hybrid of sulfonated carbon with polyaniline sulfate salt and its supercapacitor performance Ravi Bolagam, Palaniappan Srinivasan,^* Rajender Boddula

     

Induction of radiative forbidden transitions in an oxygen molecule in O<Subscript>2</Subscript>–H<Subscript>2</Subscript>O collision complexes

By the DFT/B3LYP method the equilibrium structures of oxygen complexes with water are calculated in various geometric conformations with symmetries C _2v and C _s . By the MRCI/CASSCF method potential energy surface cross-sections of the ^1.3[O₂–H₂O] complexation reaction are constructed. With taking into account the spin-orbit coupling, the forbidden transition moments a ¹Δ _g –X ³Σ _g ^?, b ¹Σ _g ⁺–a ¹Δ _g , c ¹Σ _u ^?–a ¹Δ _g , A ³Σ _u ⁺–X ³Σ _g ^? of the complexes are calculated and changes in their intensities at different geometric configurations of the complex are revealed.     

The sol–gel chromium-modified V<Subscript>6</Subscript>O<Subscript>13</Subscript> as a cathodic material for lithium batteries

A new V₆O₁₃-based material has been synthesized via the sol–gel route. This sol–gel mixed oxide has been obtained from an appropriate heat treatment of the chromium-exchanged V₂O₅ xerogel performed under reducing atmosphere. This new compound, with the chemical formula Cr_0.36V₆O_13.50, exhibits a monoclinic structure (C2/m) with the following unit cell parameters, a=11.89 Å, b=3.68 Å, c=10.14 Å, β=101.18°. The electrochemical characterization of this compound has been performed using galvanostatic discharge–charge experiments in the potential range 4–1.5 V and completed by ac impedance spectroscopy measurements. It exhibits a specific capacity of about 370 mAh g^?1, which makes the compound Cr_0.36V₆O_13.50 the best one in the V₆O₁₃-based system: 85% of the initial capacity (315 mAh g^?1) after the 35th cycle is still available at C/25 without any polarization. From impedance spectroscopy, a high kinetics of Li transport (D _Li=1.8×10^?9 cm² s^?1) is found at mid-discharge.     

Synthesis,antifungal and insecticidal activity of novel [1,2,4]triazolo[4,3-<Emphasis Type="Italic">a</Emphasis>]pyridine derivatives containing a sulfide substructure

A series of [1,2,4]triazolo[4,3-a]pyridine derivatives bearing a sulfide substructure was designed, synthesized and characterized via ¹H·NMR, ¹³C·NMR, IR and elemental analyses. Bioassay Results indicated some of the derivatives displayed good fungicidal activity on Rhizoctonia cerealis, moderated insecticidal activity against Plutella xylostella and good insecticidal activity on Helicoverpa armigera. The inhibitory effects of compounds 4g and 4u against Rhizotonia cerealis were 70.9% at 50 μg mL^?1; the IC₅₀ values of compounds 4d and 4s against Plutella xylostella were 43.87 and 50.75 μg mL^?1, respectively. And the IC₅₀ values of compounds 4d, 4q, and 4s on Helicoverpa armigera were 58.3, 77.14 and 65.31 μg mL^?1, respectively, which were better than that of commercial chlorpyrifos (103.77 μg mL^?1).