A Review of In‑Situ Techniques for Probing Active Sites and Mechanisms of Electrocatalytic Oxygen Reduction Reactions

Electrocatalytic oxygen reduction reaction(ORR)is one of the most important reactions in electrochemical energy technologies such as fuel cells and metal–O2/air batteries,etc.However,the essential catalysts to overcome its slow reaction kinetic always undergo a complex dynamic evolution in the actual catalytic process,and the concomitant intermediates and catalytic products also occur continuous conversion and reconstruction.This makes them difficult to be accurately captured,making the identification of ORR active sites and the elucidation of ORR mechanisms difficult.Thus,it is necessary to use extensive in-situ characterization techniques to proceed the real-time monitoring of the catalyst structure and the evolution state of intermediates and products during ORR.This work reviews the major advances in the use of various in-situ techniques to characterize the catalytic processes of various catalysts.Specifically,the catalyst structure evolutions revealed directly by in-situ techniques are systematically summarized,such as phase,valence,electronic transfer,coordination,and spin states varies.In-situ revelation of intermediate adsorption/desorption behavior,and the real-time monitoring of the product nucleation,growth,and reconstruction evolution are equally emphasized in the discussion.Other interference factors,as well as in-situ signal assignment with the aid of theoretical calculations,are also covered.Finally,some major challenges and prospects of in-situ techniques for future catalysts research in the ORR process are proposed.

Synthesis and Antitumor Activity of 3-[2-(4-Hydroxy-Phenyl)-Ethyl]-Benzo[d] Isoxazole-4,6-Diol

A new phloretin derivative 1 3-[2-(4-hydroxy-phenyl)-ethyl]-benzo[d] isoxazole-4,6-diol (yield 63%) was synthesized from phloretin by carbonyl nucleophilic addition condensation reaction. Its structure was characterized by 1H NMR, 13C NMR and HR-MS. The phloretin, compound 1, resveratrol and acetylated resveratrol were determined by comparing them with paclitaxel. Anti-tumor activity of alcohol on SPC-A1, EC109, A549, MCF-7 and MDA-MB-231 cell lines. Compound 1 showed better antitumor activity than docetaxel against A549 tumor cells.

Synthesis, Structural Characterization and Antimicrobial Activity of a Novel Cobalt(II) Complex Based on 3-Methyl-1-Phenyl-4-(2-Thienoyl)-Pyrazol-5-One

New cobalt(II) complex, [Co(O2C15H11N2S)2(OH2)2]∙2H2O (1∙2H2O), has been synthesized upon reaction of cobalt chloride hexahydrate (Co(Cl)2∙6H2O) with 3-methyl-1-Phenyl-4-(2-thienoyl)-pyrazol-5-one (referred as HL) in ethanol at room temperature. Single crystal X-ray diffraction (XRD), spectroscopic methods, and microelemental analyses were used to characterize 1∙2H2O. Compound 1∙2H2O crystallizes in the orthorhombic crystal system with a Pbca space group and with the cobalt atom being pseudo-octahedral coordinated. The broth microdilution technique was used to screen the free ligand (HL) and the complex (1∙2H2O) for antimicrobial activities. HL has a low activity (MIC > 100 μg/mL) on all microorganisms, whereas compound 1∙2H2O displayed moderate activity (10 ∙2H2O exhibited bactericidal and fungicidal activity respectively on all the bacteria and yeasts tested. These findings reveal that the antimicrobial activity of HL was enhanced upon coordination to Co(II) ion against all microorganisms (bacteria and fungus).

In-situ/operando techniques to identify active sites for thermochemical conversion of CO_(2) over heterogeneous catalysts

The catalytic conversion of CO_(2) to fuels or chemicals is considered to be an effective pathway to mitigate the greenhouse effect. To develop new types of efficient and durable catalysts, it is critical to identify the catalytic active sites, surface intermediates, and reaction mechanisms to reveal the relationship between the active sites and catalytic performance. However, the structure of a heterogeneous catalyst usually dynamically changes during reaction, bringing a great challenge for the identification of catalytic active sites and reaction pathways. Therefore, in-situ/operando techniques have been employed to real-time monitor the dynamic evolution of the structure of active sites under actual reaction conditions to precisely build the structure–function relationship. Here, we review the recent progress in the application of various in-situ/operando techniques in identifying active sites for catalytic conversion of CO_(2) over heterogeneous catalysts. We systematically summarize the applications of various optical and X-ray spectroscopy techniques, including Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS), in identifying active sites and determining reaction mechanisms of the CO_(2) thermochemical conversion with hydrogen and light alkanes over heterogeneous catalysts. Finally, we discuss challenges and opportunities for the development of in-situ characterization in the future to further enlarge the capability of these powerful techniques.

Synthesis, Structural Characterization and Antimicrobial Activity of a Novel Cobalt(II) Complex Based on 3-Methyl-1-Phenyl-4-(2-Thienoyl)-Pyrazol-5-One

New cobalt(II) complex, [Co(O2C15H11N2S)2(OH2)2]∙2H2O (1∙2H2O), has been synthesized upon reaction of cobalt chloride hexahydrate (Co(Cl)2∙6H2O) with 3-methyl-1-Phenyl-4-(2-thienoyl)-pyrazol-5-one (referred as HL) in ethanol at room temperature. Single crystal X-ray diffraction (XRD), spectroscopic methods, and microelemental analyses were used to characterize 1∙2H2O. Compound 1∙2H2O crystallizes in the orthorhombic crystal system with a Pbca space group and with the cobalt atom being pseudo-octahedral coordinated. The broth microdilution technique was used to screen the free ligand (HL) and the complex (1∙2H2O) for antimicrobial activities. HL has a low activity (MIC > 100 μg/mL) on all microorganisms, whereas compound 1∙2H2O displayed moderate activity (10 ∙2H2O exhibited bactericidal and fungicidal activity respectively on all the bacteria and yeasts tested. These findings reveal that the antimicrobial activity of HL was enhanced upon coordination to Co(II) ion against all microorganisms (bacteria and fungus).

Study on Component Synthesis Active Vibration Suppression Method Using Zero-placement Technique

The component synthesis active vibration suppression method （CSVS） can be applied to suppress the vibration of flexible systems. By this method, several same or similar time-varying components are arranged according to certain rules along the time axis. The synthesized command can suppress the arbitrary unwanted vibration harmonic while achieving the desired rigid body motion. The number of the components increases rapidly when the number of harmonic vibration is growing. In this article, the CSVS based on zero-placement technique is used to construct the synthesized command to suppress the multi-harmonics simultaneously in the discrete domain. The nature of zero-placement method is to put enough zeros to cancel system poles at necessary points. The designed synthesized command has equal time intervals between each component and which is much easier to be implemented. Using this method, the number of components increases linearly with the increasing of the number of being suppressed harmonics. For the spacecraft with flexible appendages, CSVS based on zero-placement is used to design the time optimal large angle maneuver control strategy. Simulations have verified the validity and superiority of the proposed approach.

Expression, Purification and Insecticidal Activity Analysis of Cry1Ac without Helix α-1

[Objective] This study aimed to analyze the expression, purification and insecticidal activity of Cry1Ac without helix α-1 of domain I in E. coli. [Method] Plasmid of B. thuringiensis HD-1 was used as the template for amplification of Cry1Ac gene, which was linked with pET28a vector to construct the recombinant plasmid. After transformation and IPTG induction, expression of target protein was detected by using SDS-PAGE method. Target protein was extracted and coated on the surface of feed for H. armigera to determine the insecticidal activity. [Result] Cry1Acdela1 gene could normally express the target protein in E. coli. However, the target protein existed in the form of inclusion body. Results of bioassay analysis showed that under the same concentration, fatality rate of activated Cry1Ac toxin reached above 75%, while that of Cry1Acdelα1 was only about 10%. [Conclusion] E. coli-expressed Cry1Acdelα1 had no insecticidal activity against H. armigera.

Techniques of Activating Textbooks for Intensive Reading

This paper presents four teaching techniques of activating the textbook for intensive reading which include:injecting contemporary elements into the text,relating the text to students' life,questioning about the text challengingly and ingeniously,and spicing up the text.

主动循环呼吸训练联合讲解-模拟-练习-沟通-支持模式护理对肺癌术后患者心理状态及心肺功能的影响

目的探讨主动循环呼吸训练(ACBT)联合讲解-模拟-练习-沟通-支持模式(ESPCS)护理对肺癌术后患者心理状态及心肺功能的影响。方法将2017年9月—2020年9月接受常规护理干预的80例肺癌术后患者设为对照组,将2020年10月—2023年9月接受ACBT联合ESPCS护理的80例肺癌术后患者设为联合组,2组患者均持续干预2个月。比较2组患者心理状态、心脏功能指标、肺功能指标、生活质量以及并发症发生情况。结果干预后,联合组心理状态优于对照组,差异有统计学意义(P<0.05)。干预后,联合组左室射血分数(LVEF)、第1秒用力呼气容积(FEV_(1))、用力肺活量(FVC)、FEV_(1)与FVC比值(FEV_(1)/FVC)、肺活量(VC)、每分钟最大通气量(MMV)、生活质量和6 min步行试验(6MWT)结果高于对照组,二尖瓣口舒张期早期和收缩早期最大血流速度比值(E/A)、左室舒张末期内径(LVEDD)、呼吸频率和Borg量表评分低于对照组,差异有统计学意义(P<0.05)。联合组并发症发生率为8.75%,低于对照组的21.25%,差异有统计学意义(P<0.05)。结论ACBT联合ESPCS护理可以改善肺癌术后患者心理状态,提高心肺功能和生活质量,降低并发症发生率。

A review on medicinal importance,pharmacological activity and bioanalytical aspects of beta-carboline alkaloid "Harmine"

Harmine,a beta-carboline alkaloid,is widely distributed in the plants,marine creatures,insects, mammalians as well as in human tissues and body fluids.Harmine was originally isolated from seeds of Peganum harmal in 1847 having a core indole structure and a pyridine ring.Harmine has various types of pharmacological activities such as antimicrobial,antifungal,antitumor,cytotoxic, antiplasmodial,antioxidaant,antimutagenic,antigenotoxic and hallucinogenic properties.It acts on gamma-aminobutyric acid type A and monoamine oxidase A or B receptor,enhances insulin sensitivity and also produces vasorelaxant effect.Harmine prevents bone loss by suppressing osteoclastogenesis.The current review gives an overview on pharmacological activity and analytical techniques of harmine,which may be useful for researcheres to explore the hidden potential of harmine and and will also help in developing new drugs for the treatment of various diseases.

A Pair of New Spirocyclic Alkaloid Enantiomers with TrxR Inhibitory Activities Were Isolated from Marine-Derived Aspergillus ruber TX-M4-1

One new spirocyclic alkaloid,5-isopentenyl-cryptoechinuline D(1),along with 11 known compounds(2–12),were iso-lated from a marine fungus Aspergillus ruber TX-M4-1.The structures of compounds 1–12 were elucidated by spectroscopic evi-dences.Compound 1 was initially isolated as an enantiomer,and further separation of 1 by chiral HPLC afforded a pair of enantio-mers,including(-)-5-isopentenyl-cryptoechinuline D(1a)and(+)-5-isopentenyl-cryptoechinuline D(1b).Their absolute configura-tions were elucidated by ECD spectroscopic data.Compounds 1a,5 and 10 could inhibit thioredoxin reductase(TrxR)activity with IC50 values of 6.2,36.3 and 18.6μmol L^(-1),respectively.Surface plasmon resonance(SPR)study also demonsrated the interactions between compounds 6,8 and Niemann-Pick C1 Like 1(NPC1L1)respectively,which indicate that compounds 6 and 8 are potential NPC1L1 inhibitors.

Accumulation of heavy metals in two crop seeds due to soil contamination as determined by neutron activation analysis techniques

Samples of two crop seeds (corn and sesame) grown on different contaminated soil sources were collected and prepared for neutron activation analysis. Soil contamination sources were organic waste compost applied to soil amendments namely, sewage sludge(Bs) and municipal solid waste (MSW) at 4%, 6% and 8% respectively. The non destructive NAA technique was used to determine some trace elements accumulation in plant seeds. Results revealed that increasing rate of tested organic waste resulted in dramatic increase in tested heavy metals levels in seeds(i.e., Fe, Zn, Co, Cr, Sc and Hg). Sesame seeds showed higher affinity to accumulate trace elements than corn grains in most tested elements. Moreover, MSW addition enhanced the accumulation of tested metals in seeds more than Bs compost.

Photocatalytic Activity of TiO_(2) Coatings Fabricated on Al_(2)O_(3) by Mechanical Coating Technique

The titanium coatings were prepared on Al_(2)O_(3) balls by mechanical coating technique (MCT),and then the coatings were oxidized to titanium oxides(TiO_(2)) films at 300-600 ℃.The effects of different milling time and oxidation temperature on thickness of films were studied.The composition and microstructure of the films were analyzed by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS).The results show that the thickest coatings with an average thickness of 20 μm were obtained at the milling time of 15 h.In addition,with the increase of the oxidation temperature,the oxidation of the film is increased.When the milling time is 15 h,the oxidation temperature is 500 ℃,and the addition of photocatalyst is 1 g/mL.The films have the best photocatalytic performance when the degradation rate of methyl orange solution reaches the maximum value of 74.9 %,and the films have a good reusability.

Estimation of active earth pressure based on pseudo-dynamic approach and discretization technique

A method combining the pseudo-dynamic approach and discretization technique is carried out for computing the active earth pressure.Instead of using a presupposed failure mechanism,discretization technique is introduced to generate the potential failure surface,which is applicable to the case that soil strength parameters have spatial variability.For the purpose of analyzing the effect of earthquake,pseudo-dynamic approach is adopted to introduce the seismic forces,which can take into account the dynamic properties of seismic acceleration.A new type of micro-element is used to calculate the rate of work of external forces and the rate of internal energy dissipation.The analytical expression of seismic active earth pressure coefficient is deduced in the light of upper bound theorem and the corresponding upper bound solutions are obtained through numerical optimization.The method is validated by comparing the results of this paper with those reported in literatures.The parametric analysis is finally presented to further expound the effect of diverse parameters on active earth pressure under non-uniform soil.

Activity of the Fungicide JS399-19 Against Fusarium Head Blight of Wheat and the Risk of Resistance

This report reviews the characteristics of JS399-19, a novel cyanoacrylate fungicide. JS399-19 strongly inhibits the mycelial growth of the fungal plant pathogens of the genus Fusarium and exhibits great potential in controlling Fusarium head blight （FHB） on wheat and other cereals. The mode of action of JS399-19 is evidently different from that of benzimidazole （for example, carbendazim） and other sort of fungicides, making it a possible replacement for carbendazim in China to manage carbendazim-resistant subpopulations of Fusarium graminearum and F. asiaticum. JS399-t9 has excellent protective and curative activity against these pathogens. Incorrect use of this fungicide, however, is likely to select for resistance. Among JS399-19-resistant mutants of F. asiaticum induced in the laboratory, the resistant level of mutants was high and the phenotype of resistance against JS399-19 was conferred by a major gene by genetic analysis. The fitness of laboratory-induced JS399-19-resistant mutants of F. asiaticum was nearly equal to that of their parents. JS399-19 lacks cross resistance with other sort fungicides. To control FHB with JS399-19 and to delay the development of the fungicide-resistance, farmers should use tank mixtures containing JS399-19 and carbendazim, metconazole, tebuconazole, or prothioconazole.

Calculation of Activity Coefficients for Components in Ti-15-3 Melt

Based on Kohler’s ternary solution model and Miedemaa’s model for calculating the heats of formation-△Hij of binary Systems, the integral equation has ben established for calculating the activity coefficients in ternarysolution. With the equation, the activity coefficients in Ti-15-3 melt have been calculated. The results show that allof components’ activity coefficients are less than 1, in other wolds, compared with ideal solution, all components takeon a negative deviation. At 2000K, the activity coefficients in Ti-15-3 melt are shown as: about 0.9 for Ti, about0.85 for V, about 0. 1 for Al, aboaut 0.5 for Cr and about 0.23 for Sn. me addition of V lowers the activity coefficient of Ti, but raise the ones of Al, Cr and Sn. These results can be directly used to calculate the evaporation loss ofAl, Cr and Sn during the ISM(Induction Skull Melting) process and at the same time estimate the reactivity betweenTi-15-3 melt and refractory during the cast production.

Creation of reversed phase high-performance liquid chromatographic technique to assay platelet-activating factor

Objective: To establish a new assay for platelet-activating factor (PAF), to compare it with bio-assay; and to discuss its significance in some elderly people diseases such as cerebral infarction and coronary heart disease. Methods: To measure PAF levels in 100 controls, 23 elderly patients with cerebral infarction and 65 cases with coronary heart disease by reversed phase high-performance liquid chromatographic technique (rHPLC). Results:rHPLC is more convenient, sensitive,specific, and less confusing, compared with bio-assay. The level of plasma PAF in patients with cerebral infarction was higher than that in the controls (P<0.01), and in patients with coronary heart disease. Conclusion: Detection of PAF with rHPLC is more reliable and more accurate. The new assay has important significance in PAF research.

基于4H-SiC APD单光子探测的主动淬灭电路研究

为了对比不同类型淬灭电路对4H-SiC雪崩光电二极管(APD)探测性能的影响,采用被动淬灭电路(PQC)和主动淬灭电路(AQC),对两种类型SiC紫外APD进行了单光子探测实验,发现在PQC较长死区时间内,会频发后脉冲现象,导致APD的暗计数率(DCR)较高,从而降低器件的信噪比;对APD后脉冲概率的时间分布进行了研究,并进一步对AQC在更高器件过偏压下单光子探测中出现的问题进行了分析,提出了电路改进方案。结果表明,通过将AQC死区时间调整至45 ns,在相同单光子探测效率下,可将器件DCR减少至原先水平的1/4;通过有效抑制后脉冲和加快APD恢复速度,AQC可使器件展现出更加优越的探测性能。此研究为SiC APD在单光子探测中的应用提供了一定的参考。

Characterization and Anti-tumor Activity of Glycopeptides from Ganoderma sinensis

The water-soluble part（GS） of Ganoderma sinense Zhao, Xu et Zhang was divided into high molecular（GS-H） and low molecular（GS-L） parts by Cellulose Super Filtration, and GS was also fractionated into four fractions, GS-1, 2, 3, and 4 by ethanol precipitation according to their molecular weights. Chemical analysis shows that GS and GS-1, 2, 3, 4 were complexes of polysaccharide and peptide. The fractions with molecular weights over 4000, GS-1, 2, 3, and GS-H show anti-tumor activities, however, the fractions with molecular weights lower than 4000, GS-4, and GS-L have no anti-tumor activity, indicating that the anti-tumor activity of Ganoderma Sinensis was caused by glucopeptides with molecular weight ranging from 4000 to 20000. Two purified glucopeptides, GS-6b and GS-7b were obtained from GS-H by ion-exchange and gel-permeation chromatography. Their molecular weights, glycosidic linkages, and configurations were detected by means of IR spectrum, sugar composition analysis, and methylation analysis. The polysaccharide parts of GS-6b and GS-7b had glucan backbone consisting of β-1→3 Glc, and side chain containing glucosyl, mannosyl, fucosyl, xylosyl, galactosyl, and glucuronic acid residues attached on 1-2, 1-4, 1-6 positions of the backbone of GS-6b, or 1-6, 1-4 positions of the backbone of GS-7b. The peptide parts in GS-6b and GS-7b were composed of 10 kinds of amino acids, including Asp, Ser, Arg, Gly, Thr, Pro, Ala, Val, Met, and Lys.

Synthesis, Crystal Structure and Antitumor Activity of (E)-4-tert-Butyl-N-(2,4-dichlorobenzylidene)-5-(1,2,4-triazol-1-yl)-thiazol-2-amine

The title compound （E）-4-tert-butyl-N-（2,4-dichlorobenzylidene）-5-（1,2,4-triazol-1-yl）-thiazol-2-amine was synthesized by the reaction of 4-tert-butyl-5-（1,2,4-triazol-1-yl）-thiazol-2-amine with 2,4-dichlorobenzaldehyde, and its crystal structure was determined by singlecrystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1 with a = 7.9748（4）, b = 10.1803（5）, c = 11.4603（6）, α = 102.882（1）, β = 100.253（1）, γ = 104.457（1）°, V = 850.95（7）3, Z = 2, F（000） = 392, C16H15Cl2N5S, Mr = 380.29, Dc = 1.484 g/cm3, S = 1.095, μ = 0.512 mm-1, the final R = 0.0301 and wR = 0.0965 for 3334 observed reflections （I 〉 2σ（I））. The preliminary antitumor activity shows that for the title compound the IC50 of Hela is 0.175 μmol/mL and that of Bel7402 is 0.156 μmol/mL.