Participation of H_2O_2 in Enhancement of Cold Chilling by Salicylic Acid in Banana Seedlings

The possible physiological mechanism of enhancement of cold tolerance by salicylic acid (SA) in banana seedlings ( Musa acuminata cv. Williams 8188) was explored. Measurements of leakage electrolyte after 2 d of recovery at 30/22 ℃ (day/night) following 3 d of cold stress at 7 ℃ showed that pretreatment with hydroponic solution containing SA 0.3-0.9 mmol/L as foliar spray under normal growth conditions (30/22 ℃) could significantly enhance cold tolerance of banana plants. The highest enhancing effect of SA occurred at 0.5 mmol/L and it showed the lowest leakage rate of electrolyte or smaller leaf wilting area after 2 d of recovery at normal temperature from 3 d of 7 ℃ or 5 ℃ cold stress. Higher concentrations (≥2.5 mmol/L) of SA, however, caused more electrolyte leakage, indicating that they aggravated chilling damage. Enhanced cold tolerance by SA could be related to H 2O 2 metabolism. Compared with water_treated seedlings (control), SA 0.5 mmol/L treatment inhibited activities of catalase (CAT) and ascorbate peroxidase (APX), increased peroxidase (POX) activity, but did not affect the activity of superoxide dismutase (SOD) under normal growth conditions, and these changes might lead to an accumulation of H 2O 2, whereas SA pretreatment enhanced the activities of CAT and APX, and reduced the increase in productions of H 2O 2 and thiobarbituric acid_reaction substances (TBARS) during subsequent 7 ℃ cold stress and recovery periods. Exogenous H 2O 2 treatments (1.5 -2.5 mmol/L) also increased cold tolerance of banana seedlings. Furthermore, pretreatment of banana seedlings with dimethylthiourea (a trap for H 2O 2) significantly inhibited cold tolerance induced by SA. These results suggested that endogenous H 2O 2 may be required for SA_enhanced cold tolerance. The significance of the interaction of SA, H 2O 2 and H 2O 2_metabolizing enzymes during cold stress has been discussed.

φ-pH diagram of V-Ti-H_2O system during pressure acid leaching of converter slag containing vanadium and titanium

To analyze the thermodynamic characteristics of leaching process of converter slag, φ-pH diagram of V-Ti-H2O system at oxygen partial pressure of 0.5 MPa, ionic mass concentration of 0.1 mol/kg and temperatures ranging from 60 to 200 ℃ was obtained by recently published critically assessed standard Gibbs energies and activity coefficients of various species. When pH2, stable regions of V3＋, VO2＋ and VO2＋ exist in the stable region of TiO2. The pH values of stable regions of vanadium and titanium decrease and redox potentials become more positive with the temperature increasing. Vanadium and titanium could be separated by one-step leaching based on thermodynamics. The experiment results of pressure acid leaching of converter slag show that leaching rates of vanadium and titanium are 96.87% and 8.76% respectively, at 140 ℃ of temperature, 0.5 MPa of oxygen partial pressure, 0.055-0.075mm of particle size, 15：1 of liquid to solid ratio, 120 min of leaching time, 500 r/min of stirring speed and 200 g/L of initial acid concentration. Vanadium and titanium could be selectively separated in the pressure acid leaching process, and the experiment result is in agreement with thermodynamic calculation result.

h‑MoO_(3)/SiO_(2)催化合成季戊四醇异辛酸酯

采用固相研磨法,制备了一系列h-MoO_(3)/SiO_(2)催化剂,这些催化剂用于季戊四醇(PER)和异辛酸(i-EHA)反应,合成季戊四醇异辛酸酯(POE),并采用X射线衍射(XRD)、傅里叶红外光谱(FTIR)、X射线光电子能谱(XPS)、N2吸附-脱附、扫描电镜(SEM)、透射电镜(TEM)对催化剂进行表征测试。结果表明,h-MoO_(3)负载量为15%的(200)晶面择优取向的h-MoO_(3)/SiO_(2)是合成POE的优良催化剂。适宜的反应工艺条件(ni-EHA/nPER=4.3,mh-MoO_(3)/SiO_(2)/mPER=0.003,T=220℃,t=4 h)下,酯化率可达90.83%,POE的选择性可达100%。

Electrokinetic-mechanism of water and furfural oxidation on pulsed laser-interlaced Cu_(2)O and CoO on nickel foam

The electrocatalytic oxidation of biomass-derived furfural(FF)feedstocks into 2-furoic acid(FA)holds immense industrial potential in optics,cosmetics,polymers,and food.Herein,we fabricated Co O/Ni O/nickel foam(NF)and Cu_(2)O/Ni O/NF electrodes via in situ pulsed laser irradiation in liquids(PLIL)for the bifunctional electrocatalysis of oxygen evolution reaction(OER)and furfural oxidation reaction(FOR),respectively.Simultaneous oxidation of NF surface to NiO and deposition of CoO and/or Cu_(2)O on NF during PLIL offer distinct advantages for enhancing both the OER and FOR.CoO/NiO/NF electrocatalyst provides a consistently low overpotential of~359 m V(OER)at 10 m A/cm^(2),achieving the maximum FA yield(~16.37 m M)with 61.5%selectivity,79.5%carbon balance,and a remarkable Faradaic efficiency of~90.1%during 2 h of FOR at 1.43 V(vs.reversible hydrogen electrode).Mechanistic pathway via in situ electrochemical-Raman spectroscopy on CoO/NiO/NF reveals the involvement of phase transition intermediates(NiOOH and CoOOH)as surface-active centers during electrochemical oxidation.The carbonyl carbon in FF is attacked by hydroxyl groups to form unstable hydrates that subsequently undergo further oxidation to yield FA products.This method holds promise for large-scale applications,enabling simultaneous production of renewable building materials and fuel.

Comparison of the Effects of H_2O_2 and Salicylic Acid on Alternative Respiratory Pathway in Aged Potato Tuber Slices

The influences of exogenous H 2O 2 and salicylic acid (SA) treatments on the alternative respiratory pathway (ARP) in aged potato (Solanum tuberosum L.) tuber slices were compared. The results showed that both H 2O 2(5.0 mmol/L) and SA (0.1 mmol/L) treatments had a significant inducing effect on ARP capacity (V alt ) and its ratio to total respiration (V alt /V t) in potato slices aged for 24 h. With a monoclonal antibody against the alternative oxidase (AOX), Western blotting results showed that both H 2O 2 and SA treatments increased the AOX expression levels in aged potato tuber slices. However, the results of oxygen isotope discrimination experiments showed that H 2O 2 had no influence on the in vivo ARP activity (ρV alt ) and its contribution to V t(expressed as ρV alt /V t) in potato slices aged for 24 h, but SA had a significant influence on the ρV alt and ρV alt /V t values of the aged potato tuber slices. These results indicate that there are differences between the effects of H 2O 2 and SA on ARP in plant tissues. Both of them possess the ability to induce ARP capacity through inducing AOX expression. However, SA can simultaneously stimulate the operation of ARP, but H 2O 2 can not.

构建双通道路径增强iCOF/Bi_(2)O_(3)S型异质结在纯水体系中光催化合成H2O2性能

太阳能光催化技术是一种绿色、经济、可持续的制备H_(2)O_(2)方法,被认为是取代传统蒽醌法最有前景的策略。然而,由于有限的光捕获能力、快速的光生载流子复合以及氧化还原能力不足等问题,单一组分光催化剂表现出温和的光催化活性。并且,在光催化合成H_(2)O_(2)反应系统中需要额外添加牺牲剂。在这项研究中,我们通过光沉积法将Bi_(2)O_(3)(BO)纳米颗粒负载于离子型有机共价框架材料(iCOF)纳米纤维上,构建一种S型异质结用于双通道路径光催化合成H_(2)O_(2)。在纯水体系中,在iCOF表面负载10 wt%BO时,复合催化剂iCOF/BO10表现出最高的H_(2)O_(2)产率,达到了9.76 mmol·g^(-1)·h^(-1)(在420 nm处的量子效率为5.5%)。这一性能分别是纯iCOF的2.2倍,纯BO的5.6倍。原位表征技术(包括原位X射线光电子能谱、DFT理论计算、活性物种捕获实验以及原位漫反射红外傅里叶变换光谱)揭示该S型异质结不仅能促进光生载流子的分离和增强光吸收能力,而且能实现氧化还原能力最大化,使得反应体系同时通过间接2e^(-)氧气还原反应和4e^(-)水氧化反应双通道路径产生H_(2)O_(2)。此外,4e^(-)水氧化反应生成的O_(2)能够通过间接2e^(-)氧气还原反应加快H_(2)O_(2)生成的反应动力学,实现光催化H_(2)O_(2)的全合成。该项工作为开发新颖催化剂实现高效光催化合成H2O_(2)提供了独特的见解。

C6H10S2O联合Nano-CaCO3对铅染毒小鼠海马学习记忆功能的影响

评价 C6H10S2O联合Nano-CaCO3对铅染毒小鼠的海马学习记忆功能产生的影响,以指导铅染毒相关问题的处理。方法 选择齐齐哈尔医学院动物实验中心提供的20-30g 健康雌性 KM 小鼠,健康清洁级,分为正常对照组、模型对照组、C6H10S2O 组、Nano-CaCO3组、联合治疗组,其中后四组均为铅染毒模型。五组的饲养条件相同,方法 /剂量建立铅染毒模型,提供对应治疗方法,通过评估体质量与血液中铅元素含量、NO含量和ACHE活力、水迷宫、新物体识别测量的结果,判断治疗效果。结果 与空白对照组比较,模型对照组的体质量显著降低(P<0.05),血铅含量显著增加(P<0.05);与模型对照组比较,C6H10S2O组和联合治疗组小鼠的体质量显著提高(P<0.05),而血铅含量仅在联合治疗组显著减少(P<0.05);其他三组的体质量和血铅含量均无统计学差异(P>0.05)。与模型对照组比较,联合治疗组的跨越隐匿平台次数和平台象限游泳路程显著增加(P<0.05);与Nano-CaCO3组比较,联合治疗组的跨越隐匿平台次数和平台象限游泳路程也显著增加(P<0.05)。五组在NO含量和ACHE活力、认知指数方面的对比,差异均不存在统计学意义(P>0.05)。结论 C6H10S2O联合Nano-CaCO3可以减少铅含量,提高体质量,对空间学习能力有一定影响,但对认知能力、学习记忆能力不存在显著影响。

A dendritic Cu/Cu_(2)O structure with high curvature enables rapid and efficient reduction of carbon dioxide to C_(2) in an H-cell

Electrocatalytic reduction of CO_(2)(CO_(2)RR)to multicarbon products is an efficient approach for ad-dressing the energy crisis and achieving carbon neutrality.In H-cells,achieving high-current C_(2)products is challenging because of the inefficient mass transfer of the catalyst and the presence of the hydrogen evolution reaction(HER).In this study,dendritic Cu/Cu_(2)O with abundant Cu^(0)/Cu^(+)interfaces and numerous dendritic curves was synthesized in a CO_(2)atmosphere,resulting in the high selectivity and current density of the C_(2)products.Dendritic Cu/Cu_(2)O achieved a C_(2)Faradaic efficiency of 69.8%and a C_(2)partial current density of 129.5 mA cm^(-2)in an H-cell.Finite element simulations showed that a dendritic structure with a high curvature generates a strong electric field,leading to a localized CO_(2)concentration.Additionally,DRT analysis showed that a dendritic struc-ture with a high curvature actively adsorbed the surrounding high concentration of CO_(2),enhancing the mass transfer rate and achieving a high current density.During the experiment,the impact of the electronic structure on the performance of the catalyst was investigated by varying the atomic ratio of Cu^(0)/Cu^(+) on the catalyst surface,which resulted in improved ethylene selectivity.Under the optimal atomic ratio of Cu^(0)/Cu^(+),the charge transfer resistance was minimized,and the desorption rate of the intermediates was low,favoring C_(2) generation.Density functional theory calculations indicated that the Cu^(0)/Cu^(+) interfaces exhibited a lower Gibbs free energy for the rate-determining step,enhancing C_(2)H_(4) formation.The Cu/Cu_(2)O catalyst also exhibited a low Cu d-band center,which enhanced the adsorption stability of *CO on the surface and facilitated C_(2)formation.This observa-tion explained the higher yield of C_(2) products at the Cu^(0)/Cu^(+) interface than that of H_(2) under rapid mass transfer.The results of the net present value model showed that the H-cell holds promising industrial prospects,contingent upon it being a catalyst with both high selectivity and high current density.This approach of integrating the structure and composition provides new insights for ad-vancing the CO_(2)RR towards high-current C_(2) products.

Effects of exogenous salicylic acid on growth and H_2O_2-metabolizing enzymes in rice seedlings under lead stress

Salicylic acid （SA） was an essential component of the plant resistance to pathogens and also plays an important role in mediating plant response to some abiotic stress. The possible effects of SA on the growth and H2O2-metabolizing enzymes in rice seedlings under lead stress were studied. When rice seedlings grown in nutrient solution containing Pb^2＋ （0, 0.05, 0.15, 0.25 mmol/L） for 18 d, the plant biomass as well as the chlorophyll content of leaves decreased with increasing Pb concentration. The pre-treatment with SA （treated with 0.1 mmol/L SA for 48 h before Pb stress） partially protected seedlings from Pb toxicity. The chlorophyll contents were significant higher in leaves of Pb-exposed with SA pre-treatment seedlings than in Pb-exposed plants at the same Pb intensity. SA pre-treated alone could significantly increase the length of shoot and root of seedlings but the vigour difference was not marked under long-term exposure to Pb toxicity. SA pre-treated influence the H2O2 level in leaves of seedlings by up-regulating the activity of superoxide dismutase （SOD）, repressing the activity of catalase （CAT） and ascorbate peroxidase （APX） depending on the concentrations of Pb^2＋ in the growth medium. The results supported the conclusion that SA played a positive role in rice seedlings against Pb toxicity.

Preparation and phase change performance of Na_2HPO_4·12H_2O@poly(lactic acid) capsules for thermal energy storage

Micro-encapsulated phase-change materials(micro PCMs) with Na_2 HPO_4·12 H_2 O encapsulated in poly(lactic acid)(PLA) shell were prepared by a solvent evaporation–precipitation method that involves the use of a coaxial needle. The effects of PLA concentration, stirring speed, injection rate of core and shell solutions, and polyvinyl alcohol(PVA) concentration on phase change properties were investigated. The thermal properties of microP CMs were characterized by differential scanning calorimetry(DSC). The capsules prepared under the optimal conditions are about 2 mm in diameter and show a latent heat of up to 122.2 J·g^(-1).

Nitric acid pressure leaching of limonitic laterite ores:Regeneration of HNO3 and simultaneous synthesis of fibrous CaSO4·2H2O by-products

An innovative technology,nitric acid pressure leaching of limonitic laterite ores,was proposed by our research team.The HNO3 regeneration is considerable significance for the improvement of the proposed technology and its commercial application,but it has not been systematically investigated.Herein,regenerating HNO3 from Ca(NO3)2 solution with low-cost H2SO4,and simultaneous synthesis of fibrous CaSO4·2H2O by-products were studied.As a theoretical basis,the solubility of CaSO4·2H2O in HNO3 medium is studied.It is concluded that the solubility of CaSO4·2H2O increases with increasing temperature or increasing HNO3 concentration,which has considerable guiding significance for the subsequent experimental research and analysis.Then,the effects of various factors on the residual Ca^2+ concentration of filtrate,the regenerated HNO3 concentration and the morphology of synthesized products are investigated using ICP-AES and SEM.And the effect mechanism is also analyzed.The results indicate the regenerated HNO3 concentration reaches 116 g/L with the residual Ca^2+ concentration being 9.7 g/L at the optimum conditions.Moreover,fibrous CaSO4·2H2O by-products with high aspect ratios(length,406.32μm;diameter,14.71μm;aspect ratio,27.62)can be simultaneously synthesized.

Highly efficient synthesis of 2,3-dihydroquinazolin-4(1H)-ones catalyzed by heteropoly acids in water

Heteropoly acids efficiently catalyzed the cyclocondensation reaction of anthranilamide with aldehydes in water at ambient temperature and afforded the corresponding 2,3-dihydro-4（1H）-quinazolinones compounds in good to excellent yields.This method provides mild reaction conditions and clean reaction profiles,using a small quantity of catalyst and a simple workup procedure.

Design of hierarchical, three-dimensional free-standing single-atom electrode for H2O2 production in acidic media

Electrochemical reduction of molecular O2 to hydrogen peroxide(H2O2)offers a promising solution for water purification and environmental remediation.Here,we design a hierarchical free-standing single-Co-atom(with Co-N4 coordination)electrode for oxygen reduction reaction(ORR)via a two-electron pathway to make H2O2 in acidic media.The current density of the single-Co-atom electrode reached 51 mA/cm2 at 0.1 V vs reversible hydrogen electrode,lasting for more than 10 hours of continuous operation with H2O2 selectivity greater than 80%.Toward practical application,the single-Co-atom electrode was directly used to assemble an electrochemical cell to produce H2O2 at a rate of 676 mol/kgcat/h with a cell voltage of about 1.6 V.

Three New Zn(Ⅱ)/Cd(Ⅱ) Coordination Polymers Constructed with 2-Mercaptonicotinic Acid and 1,2-Di(4-pyridyl)ethylene: Syntheses and Structure Analysis

Three new Zn（Ⅱ）/Cd（Ⅱ） coordination polymers based on 2-mercaptonicotinic acid （H2mna） with 1,2-di（4-pyridyl）ethylene （dpe） introduced as a bridging ligand have been synthesized via hydrothermal method and structurally characterized by single-crystal X-ray diffraction as well as elemental analysis and IR. As reported in this paper, [Zn2（dpe）0.5（mna）2] （1） can be classified as a two-dimensional layer structure in which the 1D chain composed of Zn（Ⅱ） and mna ligands is bridged by dpe ligands, while the complex named [Zn4（dpe）4（mna）4] （2） is a tetra-nuclear cluster compound. These two compounds are further extended to three-dimensional structures by hydrogen bonds along with C–H…π and π…π interactions. Compound 3 with general formular [Cd2（dpe）0.5（mna）2]·H2O belongs to a three-dimensional porous structure in which the 2D metal layers formed by the coordination of Cd（Ⅱ） and mna ligands are connected with the bridging of dpe ligands.

Synthesis of visible light responsive ultrafine K_4Ce_2Nb_(10)O_(30) by a stearic acid method

K4Ce2Nb10O30 ultrafine powders were prepared by stearic acid method (SAM). The obtained products were analyzed by X-ray diffraction, transmission electron microscopy, energy dispersive X-ray spectrometry, scanning electron microscopy and UV-visible absorption spectra. XRD patterns revealed that K4Ce2Nb10O30 powders treated at 900 oC for 2 h presented tetragonal structure without the presence of deleterious phases. Furthermore, the K4Ce2Nb10O30 prepared by SAM had considerable activity under visible light irradiation.

Hydrothermal Syntheses and Crystal Structures of Two Metal-organic Complexes with 2,3-Pyridinedicarboxylic Acid and 2-Methyl-dipyrido[3,2-f:2',3'-h]quinoxaline Ligands

Two unusual one-dimensional（1-D） compounds,viz.[Co（Medpq）（QUI）·H2O]2n· 2.4nH2O 1 and [Cd（Medpq）（QUI）·H2O]n·nH2O 2,were synthesized by the combination of two different metallic salts and organic ligands,namely 2,3-pyridinedicarboxylic acid（H2QUI） and 2-methyldipyrido[3,2-f：2＇,3＇-h]quinoxaline（Medpq） ligand.The compounds were characterized by elemental analyses,TG,fluorescent emission and single-crystal X-ray diffraction analyses.

CRYSTAL STRUCTURE OF BINUCLEAR Y(Ⅲ) COMPLEX WITH p-METHYLBENZOIC ACID, Y_2(p-CH_3C_6H_4COO)_6(C_(12)H_8N_2)_2

Y_2(p-CH_3C_6H_4COO)_6(C_(12)H_8N_2)_2, Mr=1349.08, triclinic, space group P, a=13.00(3), b=19.743(2), c=12.754(3)A, α=97.94(1), β=106.24(2), γ=91.66(1)°, V=3177(1)~3, Z=2, Dc=1.41gcm^(-3), λ(MoKα)=0.71069, μ=18.92 cm^(-1), F(ooo)=1384, T=295K, final R=0.073 for 6504 observed reflections with Ⅰ>36(Ⅰ). There are two nonidentical binuclear molecules with different bridging connection patterns in a cell. One has four bridging carboxyl groups bound two Y(Ⅲ) ions and another only has two. The Y-Y distance is 4.196 for the former and 5.302 for the latter respectively.

The Mechanism of Sol-Gel Synthesis of Normal Spinel LiMn_2O_4 with Chelation of Citric Acid

The sol-gel process of citric acid chelating with metal cations for the synthesis of normal spinel LiMn 2O 4 and the reaction mechanism were investigated by means of XRD,IR,TG-DTA, and SEM.The results show that at the beginning lithium citrate and chelate compound of citric acid with manganese ions formed,and then with heating the esterification and condensation reactions occured between them and glycol.The products obtained are polymers in which metal cations are distributed homogeneously on atomic scale that ensure high reactivity to cations of Li + and Mn 2+.Firing the gel prepared by this process,the lattice diffusions of solid reactant ions caused by non-homogeneity of reactants are eliminated and avoided.At 400℃ phase-pure LiMn 2O 4 with nanometer scale crystallization having precise stoichiometry and perfect crystallization can be obtained.The model of chelate coordinate of double-molecule between citric acid and Mn 2+ in the gel network is proposed.It is important for explaining the dispersion state of Mn 2+ and the formation process of gel by this model.

A Green Synthesis of 2-Ethylanthraquinone by Dehydration of 2-(4'-ethylbenzoyl) benzoic Acid over Solid Acid Catalysts

The dehydration of 2-（4＇-ethylbenzoyl） benzoic acid （BE acid） to 2-ethylanthraquinone （2-EAQ） was investigated over solid acid catalysts. The results showed that H-beta zeolite catalyst modified by dilute HNO3 solution exhibited an excellent performance. In our study, the conversion of BE acid can reach 96.7%, and the selectivity to 2-EAQ is up to 99.6%.