Purification and Spectral Characteristics of Cytochrome b-559 from Oxygen-evolving Photosystem Ⅱ Core Complexes of Spinach and Rice

Cytochrome b_559 in photosystem Ⅱ reaction center was purified from spinach ( Spinacia oleracea L.) and rice ( Oryza sativa L.) by a rapid and simple procedure. Their low temperature fluorescence emission and excitation spectra, ultraviolet fluorescence spectra and absolute absorption spectra were presented. The author's purification methods, which enhanced the yield of pure protein and shorted the time for isolation, have several advantages: 1. use of oxygen_evolving PSⅡ core complexes as the starting material in order to avoid disturbing from other cytochromes; 2. isocratic elution of cytochrome b_559 from a DEAE_Sephacel column for eliminating the impurity and yielding the protein in pure state; 3. a simple column procedure for removal of excess Triton X_100. Purified cytochromes b_559 from these species have similar optical spectra and mobility during gel electrophoresis under native conditions. From the results of novel electrophoresis (Tricine_SDS_PAGE), cytochrome b_559 from both spinach and rice reveal two polypeptide bands (apparent molecular weight 9 kD and 4 kD, respectively). By measuring of 77 K fluorescence spectra, it was shown that for the purified cytochrome b_559 there were two excitation peaks at 439 nm and 413 nm, and two emission peaks at 563 nm and 668 nm. This is the first indication that Cyt b_559 is able to emit fluorescence and also transfer excited electrons to chlorophyll. By the use of ultraviolet fluorescence spectra, it was demonstrated for the first time that the location of Trp residue could be in the hydrophobic transmembrane region of cytochrome b_559.

Dioxygen Affinity and Catalytic Performance of Bis-(furaldehyde) Schiff Bases Co(II) Complexes in Cyclohexene Oxidation

Oxygenation constants and thermodynamic parameters DeltaH degrees and DeltaS degrees of cobalt (II) complexes with bis-(furaldehyde) Schiff bases (1, 2, 3, 4)were obtained by mearsuring saturated dioxygen uptake of these complexes in pyridine at different temperature. These complexes could activate molecular oxygen and were used as catalysts in cyclohexene oxidation. The influence of ligand structure on the dioxygen affinity and catalytic activity of the complexes were discussed.

Studies on Transition Metal Complexes of Schiff Base( Ⅰ )——Oxygen-carrying Properties of Cobalt( Ⅱ )Schiff Base Complexes

Introduction The compounds that can take up and release molecular oxygen reversibly is of significance because they can be used as model compounds for the study of the reversible oxygenation mechanisms involved in the very complex natural oxygen carriers, e.g., the hemoglobins and hemocyanins, and as the means of separating molecular oxygen from the air. The dioxygen carriers extensively studied are the Cobalt

An investigation of oxygen pressure acid leaching of Gacun complex Cu-Pb bulk concentrate

The treatment of the Gacun complex Cu-Pb bulk concentrate with high Zn,Ag,etc.,by oxygen pressure acid leaching was studied.The pri-mary copper and leadminerals in the concentrate are tetrahedrite and galena.The treatment of tetrahedrite was rarely studied,and most of silver occurred in themineral too.The optimum operating parameters of oxygen pressure acid leaching were established by conditional tests.Under these parameters,the result of pilot scale test showed that the leaching percentages of copper and zinc were separately as high as 98.9 wt.% and 94.9 wt.%,while lead and silver were transformed into sulfate and sulfide precipitations,respectively.The copper and zinc in lixivium were reclaimed by extraction-electrowinning and purification-electrowinning,respectively,and the lead and silver in the residue were reclaimed separately by carbonate transformation-silicofluoric acid leaching and thiourea leaching.

Co(II)-salen complex encapsulated into MIL-100(Cr) for electrocatalytic reduction of oxygen

Co（Ⅱ）-salen was encapsulated in MIL- 100（Cr） metal organic framework by ＂ship in a bottle＂ to synthesize a new electrocatalyst, Cosalen@MIL- 100（Cr）. The material was characterized by XRD, FT-IR, UV-Vis and N2-adsorption. The Cosalen@MIL-100（Cr） modified glassy carbon electrode exhibits a well-defined reduction peak at the potential of -0.21 V toward the oxygen reduction reaction （ORR） by cyclic voltam- metry （CV） in pH = 6.84 phosphate buffer. Almost 400 mV positive shift of potential at Cosalen@MIL-100（Cr） modified electrode for ORR compared with that at bare glassy carbon, indicates that Cosalen@MIL-100（Cr） possesses excellent electrocatalytic activity. The transferred number of electrons for ORR was determined by chronocoulometry. The result suggests that the introduction of Co（II）-salen complex into MOF increases the electrocatalytic activity via a four-electron reduction pathway. Furthermore, this electrocatalyst exhibits good stability and reproducibility.

Anthraquinone Derivative Chiral Schiff Base Copper（Ⅱ） Complexes for Enzyme Type Bio-Fuel Cell Mediators

Electrochemically, laccase, a family of multi-copper oxidase, has specificity for performing not only one-electron oxidation of phenolic-related compounds but also four-electron reduction of oxygen, which is expected to be a cathode of biofuel ceils. We have prepared three amino-acid derivatives （for enhancing affinity to laccase） and one control （just for determining redox behavior of ligands and Cu（II/I）） copper（lI） complexes 0-3 having phenolic-related ligands involving anthraquinone moiety. Enhancing current density of electron transfer between the cathode （composed of electron conducting materials such as Nation and carbon nanotube） and laccase could be observed for all 1-3 acting as good mediators according to （spectro）electrochemical results.

Photodegradation of bisphenol A in Fe(Ⅲ)-oxalate complexes solution

The aqueous photodegradation of bisphenol A （BPA） in the presence of Fe（Ⅲ）-oxalate complexes （Fe（Ⅲ）-Ox）, which are common compositions of natural water, was investigated in this study. BPA underwent rapid indirect photolysis in Fe（Ⅲ）-Ox solution under simulated solar irradiation, proceeding pseudo-first-order kinetics. The photolysis rate increased with decreasing pH or initial BPA level and increasing Fe（Ⅲ）/oxalate concentration ratio. Hydroxyl radicals （·OH）, which were generated from the photochemical processes of Fe（Ⅲ）-Ox complexes and contributed to the photooxidation of BPA, were determined by molecular probe and electron spin resonance （ESR） methods with the steady-state concentration of 2.56 × 10^-14 mol/L. Superoxide anion radical （O2^·-） was considered as the precursor of. OH and qualitatively determined by adding nitro blue tetrazolium as well as ESR experiments. Based on the structural analysis of the intermediate photoproducts of BPA in Fe（Ⅲ）-Ox complexes solution, the possible degradation pathways of BPA were proposed, involving ·OH addition, alkyl scission and alky oxidation. The results indicate that the photochemical reactivity of Fe（Ⅲ） may affect the environmental fate of BPA in natural water significantly.

In situ doping brushite on zinc manganese oxide toward enhanced water oxidation performance: Mimicry of an oxygen‐evolving complex

We report in situ doping of brushite on zinc manganese oxide（ZMO）, fabricated by calcining a Mn（II） oxalate‐impregnated metal‐organic framework. The doping process was conducted in com‐bination with the photocatalytic water oxidation reaction which was catalyzed by ZMO in neutral phosphate‐buffered aqueous solution containing [Ru（bpy）3]^2＋‐Na2S2O8 and calcium（II） triflate salt, exhibiting greatly enhanced water oxidation performance with optimized turnover frequency of 0.18 mmol（O2） mol（Mn）^（–1） s^（–1）. Different analytical techniques indicated that photodeposited calci‐um‐phosphate（CaP） acted as a co‐catalyst to promote the O2 evolution activity of ZMO. This system involved the use of manganese oxide and calcium ion, and the operation was conducted under am‐bient temperature and neutral conditions, thus, it efficiently mimicked the oxygen‐evolving complex in photosystem II.

Oxygen pressure acid leaching of Gacun complex Cu concentrates

The treatment of the Gacun complex Cu concentrate with high contents of Pb,Zn,Ag,etc by oxygen pressure acid leaching was studied.It is unusual that tetrahedrite,whose treatment was rarely studied,is the primary copper mineral of the concentrates.Most of silver also occurs in the mineral.The optimum operating parameters of oxygen pressure acid leaching were established by conditional tests.Pilot scale test was carried out under the parameters,and the leaching rates of copper and zinc are as high as 97.10% and 89.83% while lead and silver are transformed into sulfate and sulfide respectively and stay in leaching residue.The copper and zinc in lixivium were reclaimed by extraction-electrowinning and purification-electrowinning,respectively,and the lead and silver in the residue were reclaimed separately by chloride leaching and thiourea leaching.The extraction rate of copper achieves 96%,and the leaching rates of lead and silver reach 90% and 95%,respectively.

Synthesis, oxygenation and catalytic performance of manganese complex with p-aminomethyl benzoic acid Schiff base

The amino acid Schiff base complex (Sal-AMBA-Mn) was prepared with p-amino-methylbenzoic acid, salicylaldehyde and Mn(OAc)2·4H2O. Its structures was characterized with IR and UV spectra. Oxygenation mechanism of the complex in N, N-dimethylformamide solution was investigated. The results show that lower temperature is in favor of the oxygenation, and energy, enthalpy and entropy are -3.8 kJ/mol, -4.2 J/mol and -161.44 J/(mol·K), respectively. In the presence of the manganese complex, dehydroepiandrosterone acetate is effectively oxidized by molecular oxygen and the corresponding enone 7-ketodehydroepiandrosterone acetate is obtained. The yield is 62.1% when the oxidation is carried out under the reaction conditions of 60 ℃, 2 MPa of O2 pressure, C5H5N as a solvent and molar ratio of the substrate to the complex of 1:10.

Suppression and compensation effect of oxygen on the behavior of heavily boron-doped diamond films

This work investigates the suppression and compensation effect of oxygen on the behaviors and characteristics of heavily boron-doped microwave plasma chemical vapor deposition(MPCVD)diamond films.The suppression effect of oxygen on boron incorporation is observed by an improvement in crystal quality when oxygen is added during the diamond doping process.A relatively low hole concentration is expected and verified by Hall effect measurements due to the compensation effect of oxygen as a deep donor in diamond.A low acceptor concentration,high compensation donor concentration and relatively larger acceptor ionization energy are then induced by the incorporation of oxygen;however,a heavily boron-doped diamond film with high crystal quality can also be expected.The formation of an oxygen–boron complex structure instead of oxygen substitution,as indicated by the results of x-ray photoelectron spectroscopy,is suggested to be more responsible for the observed enhanced compensation effect due to its predicted low formation energy.Meanwhile,density functional theory calculations show that the boron–oxygen complex structure is easily formed in diamond with a formation energy of-0.83 eV.This work provides a comprehensive understanding of oxygen compensation in heavily boron-doped diamond.

Formation and Evolution of Chromitites in the Hongshishan Complex,Beishan Orogenic Collage,NW China:Constraints from Mineralogical Compositions,Re-Os Isotopes and Platinum-Group Element Geochemistry

The Hongshishan chromitite deposits are situated to the north of the Beishan orogenic collage,in the southern part of the Central Asian Orogenic Belt.This study describes the mineral chemistry,Re-Os isotopes and platinum-group elements geochemistry of the Hongshishan chromitites for the purpose of constraining the origin,evolution and composition of their parental melts.The restricted ranges of Al_(2)O_(3),Cr_(2)O_(3)and Cr#-Mg#variation of chromite-cores and chromites fall within the field of the mid-ocean ridge and ophiolitic podiform chromite settings.The(^(187)Os/^(188)Os)i ratios of the chromitites are in the range of 0.12449–0.12745(average 0.12637)and theγOs are from-1.92 to-0.06(average-0.83).In the Re-Os isotope diagrams,all the samples fall in the field of chromitites and show a residual peridotitic trend.The range of Os isotopic compositions andγOs values indicate that they overlap the depleted MORB mantle(DMM)as well as being close to global Os isotopic data andγOs of ophiolite chromitites.The characteristics of the PGE contents can be roughly subdivided into two groups:podiform chromitites and Ural-Alaskan type complexes.For the ferritchromite cores,the calculated Al_(2)O_(3)concentrations of the parental melt are higher(average 16.65 wt%)in high-Cr than high-Al chromitite(average 16.17 wt%)and for the chromite,the calculated Al_(2)O_(3)concentrations are even higher(average 16.48 wt%)in the high-Cr than the high-Al examples(average 15.38 wt%).In the(TiO_(2))melt vs.TiO_(2)diagrams,most high-Al melts fall in the MORB,while the high-Cr melts fall in the ARC field.The calculated Fe O/Mg O ratios for the parental melt show the closest resemblance to a MORB magma composition.The inferred parental melt composition for studied chromitites falls in the field of mid-ocean ridge basalt(MORB)magmas and far away from boninite.The calculated degrees of partial melting producing the chromitites are 16%-22%(average 19%),which is around the range of those of the MORB magmas.The chromitites are suggested to have been formed in a MORB setting.The chromites and ferritchromite cores are mostly scattered along the MORB and SSZ harzburgite–dunite fields.Ferritchromite rims and ferritchromites with high YFes formed as a result of alteration during serpentinization..

草酸与铁氧化物相互作用及光化学活化分子氧过程的研究进展

草酸与铁氧化物共存于自然环境中,二者之间的相互作用及光化学行为强烈影响着分子氧的活化.而分子氧活化影响共存体系中污染物的迁移与转化,是发展绿色污染控制氧化技术的关键.因此,探讨草酸与铁氧化物之间的相互作用与光化学活化分子氧是目前的研究热点之一.本文系统总结了近年来围绕草酸与铁氧化物相互作用以及草酸诱导铁氧化物活化分子氧的研究成果,论述了草酸在铁氧化表面的吸附与转化特性、草酸铁络合物光化学过程以及活性氧产生与转移途径,同时探讨了上述过程对环境污染物降解的影响,借此加深理解草酸诱导铁氧化物环境光化学行为与活化分子氧原理,并对今后的研究发展方向提出了展望,以期为利用天然铁氧化物和有机质发展原位环境修复技术提供依据.

PN^(3)P-钳型镍硝酸根配合物的合成及光反应性质

PN^(P-)钳型镍硝酸根配合物2可通过其前体镍氯化物1与硝酸银复分解反应制备,产率高达95%;配合物2的结构通过核磁、红外、HRMS、X-射线单晶衍射等表征进行了确认,其中硝酸根以η^(1)-ONO_(2)的方式与金属镍配位。配合物2具有优异的光反应性质,通过控制光照时间,可分别转化为钳型镍硝基配合物3、氧原子分子内转移的硝基配合物4和配体磷完全氧化的镍双硝酸根配合物5。它们的结构均通过核磁和单晶表征证实,配合物3的结构还通过对比1与亚硝酸银反应生成产物的核磁数据进行了验证。

尿酸对果蝇幼虫生长发育的影响及机制分析

目的探讨尿酸(UA)对果蝇幼虫生长发育的影响及其机制。方法收集刚孵化的野生型黑腹果蝇(W1118)1龄幼虫1350只,采用高嘌呤饮食构建高尿酸血症果蝇模型,分为对照组(标准玉米粉培养基)、低浓度干预组(含0.05%腺嘌呤的玉米粉培养基)和高浓度干预组(含0.10%腺嘌呤的玉米粉培养基),每组150只,另设2个平行实验组,观察各组幼虫的生长发育情况,测定果蝇体内UA和激素水平,以及生长发育相关基因的表达情况。结果与对照组比较,低浓度干预组和高浓度干预组果蝇体内UA水平均显著增高(P均<0.001)、果蝇幼虫发育时间显著延长(P=0.024,P<0.001),高浓度干预组果蝇幼虫的生存率、蛹化率、羽化率均显著降低(P均<0.001),而果蝇幼虫体内保幼激素(JH)、20-羟基蜕皮甾酮(20E)水平均显著升高(P均<0.001)。PCR结果显示,与对照组比较,高浓度干预组果蝇幼虫体内活性氧(ROS)、叉头框O亚型(FOXO)、哺乳动物雷帕霉素靶蛋白(mTOR)mRNA的表达水平显著增高,应激诱导蛋白Sestrin、mTOR复合物1(mTORC1)、AMP活化的蛋白激酶mRNA的表达水平显著降低(P均<0.001)。结论高浓度UA可能通过调节果蝇体内JH、20E的表达,促进ROS/FOXO/mTORC1/mTOR信号通路的表达水平,从而抑制果蝇幼虫的生长发育。

基于荧光猝灭原理的比率式光纤溶解氧传感器研究

溶解氧浓度的准确测定在医疗应用、海洋监测、工农业生产等领域中,起到至关重要的作用。本篇论文提出了一种比率式光纤溶解氧传感器,以四乙氧基硅烷(TEOS)和正辛基三乙氧基硅烷(Octyl-triEOS)为前驱体的有机改性硅酸盐(ORMOSILs)作为载体基质,选用三(4,7-联苯-1,10-邻菲啰啉)二氯化钌(Ru(dpp)_(3)^(2+))为氧敏感染料,选用7-氨基-4-(三氟甲基)香豆素(AFC)为参比染料。吸收光谱表明,氧敏感染料和参比染料可以被中心波长为405nm的光源激发。发射光谱表明,氧敏感染料和参考染料的发射波长没有光谱重叠,因此可以使用比率法测量溶解氧浓度。通过溶胶-凝胶工艺制备的ORMOSILs将氧敏感染料和参比染料固定在塑料光纤端部,从而形成复合氧敏感薄膜,对传感膜的厚度和疏水性进行了表征,传感膜的厚度为569μm,水接触角为81°。将该传感器在水溶液中进行了测试,在光源激发下,氧敏感染料和参考染料在605和490nm处有明显的发射峰,随着溶解氧浓度的增加,氧敏感染料的荧光强度降低,而参比染料的荧光强度稳定在某一数值,通过测量氧敏感染料与参比染料的比率,达到检测氧浓度的目的。采用Stern-Volmer方程对溶解氧浓度和荧光强度比进行线性拟合,该传感器在0~20.05mg·L^(-1)溶解氧范围内,Stern-Volmer拟合度可达98.22%,灵敏度可达0.4334/[O_(2)],从饱和氮溶液到饱和氧溶液传感器的响应时间为12s,从饱和氧溶液到饱和氮溶液传感器的恢复时间为144s,引入非对称因子ASY表明传感时间的不对称性。对传感器的光稳定性和重复性进行了测试,比率式光纤传感器可以克服光源波动,相对单荧光强度传感有更强的稳定性。

一种水体长效增氧复合体及其功效研究

本研究旨在评估一种新型水体长效增氧复合体在静水水体中的增氧效果。研究结果显示,复合体方圆25 cm范围内,增氧效果显著,溶氧水平存在显著差异。在为期14 d的监测期内,与对照组相比,复合体周围的溶氧含量基本上都更高。展现出了长期且良好的增氧效果。本研究首次揭示了新型长效水体增氧复合体的增氧性能,填补了养殖水体长效增氧方面的研究空白,为水体增氧剂的发展提供了有力的数据支撑。

体外膜肺氧合辅助治疗高危复杂冠心病患者行PCI的临床效果

目的评估体外膜肺氧合(ECMO)辅助治疗接受经皮冠状动脉介入(PCI)的高危复杂冠心病患者(complex high-risk and indicated patients,CHIPs)的临床效果。方法回顾性分析52例CHIPs并接受PCI治疗的患者,按ECMO辅助时机分为术前辅助组(n=24)和术中辅助组(n=28)。对比两组患者基线资料、术前状态、院内病死率、冠状动脉造影结果、冠状动脉评分及并发症发生率。结果术前辅助组院内病死率显著低于术中辅助组(12.5%vs.64.3%,P<0.001)。术前辅助组中有5例(20.8%)联合使用主动脉内球囊反搏(intra-aortic balloon pump,IABP),而术中辅助组则为14例(50%)。两组白细胞计数、高密度脂蛋白水平、术中最差乳酸值及总病死率差异有统计学意义(均P<0.05),术前辅助组表现更佳。术前辅助组神经系统、心脏及四肢并发症的发生率也显著低于术中辅助组(均P<0.05),但冠脉评分、冠状动脉造影结果、冠脉血管病变程度、体外膜肺氧合上机操作时间、辅助时间及PCI手术时间等差异无统计学意义(均P>0.05)。结论ECMO辅助CHIPs患者PCI治疗时,术前应用更能有效降低病死率及ECMO相关并发症的发生率,可为CHIPs患者的治疗提供一种更为优化的策略。

“双碳”目标下中国社会——生态复合系统碳氧平衡时空格局分析

在“双碳”战略目标下,如何同步实现“稳增长”和“碳减排”,成为中国推进可持续发展、生态保护和高质量发展并重的焦点问题。论文基于碳氧平衡系数测算分析我国社会—生态复合系统2000—2020年排碳耗氧量、固碳释氧量以及碳氧平衡状况的时空格局。结果表明:2000年我国碳氧处于平衡状态,社会生态系统处于良性循环,随后,随着经济快速发展,排碳耗氧量剧增,同时,土地利用变化剧烈,林地和草地面积减少,固碳释氧量下降,导致碳氧处于失衡状态。进一步的碳氧平衡省际分析可知,2020年我国省际碳氧平衡差异明显,东部和中部大多数省份社会—生态复合系统处于碳氧失衡状态。测算分析社会—生态复合系统碳氧平衡时空格局,可为土地利用结构优化配置及不同区域间生态补偿和碳排放交易提供指导。