An explanation to the high efficiency ofm-THPC (temporfin) used in photodynamic therapy

Meso-tetrahydroxylphenyl chlorin (m-THPC) is one of the most efficient prospective sensitizers used in photodynamic therapy (PDT). ESR spectroscopy, fluorescence quenching experiments and cyclic voltammogram measurement were used to study its redox properties. The results showed that the ability of m-THPC generating superoxide radical anions was very strong, and the rate constant of m-THPC fluorescence quenching by oxygen k_q (O₂)=1.46×10¹⁰ mol^-1·s^-1. The values of fluorescence quen- ching rate constant of m-THPC by some other electron acceptors, such as methyl viologen (MV²⁺) and anthraquinone (An), were also measured. And they were k_q (MV²⁺)=5.51×10⁹ mol^-1·s^-1, k_q (An)=7.81×10⁹ mol^-1·s^-1. The oxidation potential of m-THPC was examined to be +0.62 V (vs. NHE) in acetonitrile. All these suggested that m-THPC should be a much stronger electron donor than photofrin, the currently used in clinical photodrug, and may react easily through electron transfer with biological matter to yield various radicals. So it seemed reasonable that the type Ⅰ reaction may play an important role in the high activity of m-THPC-PDT.     

Partial oxidation of methane to syngas in tubular oxygen-permeable reactor

A dense Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ membrane tube was prepared by the extruding method. Furthermore, a membrane reactor with this tubular membrane was successfully applied to partial oxidation of methane (POM) reaction, in which the separation of oxygen from air and the partial oxidation of methane are integrated in one process. At 875℃, 94% of methane conversion, 98% of CO selectivity, 95% of H₂ selectivity, and as high as 8.8 mL/(min · cm²) of oxygen flux were obtained. In POM reaction condition, the membrane tube shows a very good stability.     

Effect of Mn cluster on the formation of superoxide radicals in photoinhibition of photosystem Ⅱ

To further realize the action of superoxide radicals (O₂^{− .}) in photoinhibition of photosystem Ⅱ (PSⅡ), we employed 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a spin trap, associated with EPR spectroscopy, to study the effect of illumination time on O₂^{− .} formation during high light photoinhibition in PSⅡ membranes and Mn-depleted PSⅡ membranes. Results indicated that the removal of Mn cluster from PS
membranes has a strong influence on the dynamics of superoxide formation. The relative mechanism was also discussed. These novel findings may further promote the studies of the structure and function of PSⅡ and the mechanism of photoinhibition.     

Experimental measurement of the electrical conductivity of single crystal olivine at high temperature and high pressure under different oxygen fugacities

At 1.0?4.0 GPa and 1123?1473 K and under oxygen fugacity-controlled conditions (Ni+NiO, Fe+Fe₃O₄, Fe+FeO and Mo+MoO₂ buffers), a YJ-3000t Model six-anvil solid high-pressure apparatus and a Sarltron-1260 Impedance/Gain-Phase analyzer were employed to conduct an in situ measurement of the electrical conductivity of single crystal olivine. Experimental results showed that: (1) within the range of experimentally selected frequencies (10³?10⁶ Hz), the electrical conductivity of the sample is of great dependence on the frequency; (2) with the rise of temperature (T), the electrical conductivity (σ) will increase, and the Arrenhius linear relationship is established between lgσ and 1/T; (3) under the control of oxygen buffer Fe+Fe₃O₄, with the rise of pressure, the electrical conductivity tends to decrease whereas the activation enthalpy and independent-of-temperature preexponential factor tend to increase, with the activation energy and activation volume of the sample estimated at (1.25±0.08) eV and (0.105±0.025) cm³/mol, respectively; (4) under given pressure and temperature conditions, the electrical conductivity tends to increase whereas the activation energy tends to decrease with increasing oxygen fugacity; and (5) the mechanism of electrical conduction of small polarons can provide insight into the behavior of electrical conduction of olivine under high pressure and high temperature.     

Investigation of novel zirconium based perovskite-type mixed conducting membranes for oxygen separation

A series of BaZr_0.2Co_0.8-xFe_xO_3-δ materials for oxygen separation were synthesized through a citric and EDTA acid combined complexing method, and their crystal structures, oxygen permeabilities, sintering and sealing abilities were investigated. The results showed that the cubic perovskite structure was formed for materials in the composition range investigated. Oxygen permeation flux and stability, as well as sintering and sealing abilities of the synthesized materials were increased or improved apparently due to the introduction of zirconium. For example, the oxygen permeation flux reached 0.8 mL/min·cm² when x = 0.2 or 0.3 at 950℃, and a stable time-related oxygen permeation flux was found for the BaZr_0.2Co_0.3Fe_0.5O_3-δ membrane at 800℃.     

Voltammetric studies on free radicals of lower fatty alcohols

In this work, both generation and reduction processes of the a -radicals of lower fatty alcohols were studied by voltammetry in lower fatty alcohols/peroxydisul- fate/phosphate buffer system. Experimental results showed that such three reactions were successively completed at negative potential on mercury electrode surface: (ⅰ) sulfate radical anion SO₄^.- was generated electrochemically from one-electron reduction of peroxydisulfate ion S₂O₆^2-, (ⅱ) the SO₄^.-oxidized lower fatty alcohols to the corresponding a -radicals and (ⅲ) the a -radicals were reduced in one-electron and one-proton addition to produce their own reduction waves. The apparent free energy ΔrGm of the a -radicals of lower straight-chain fatty alcohols such as methanol, ethanol, propanol, butanol and pentanol obtained were 107.09, 116.74, 122.53, 126.39 and 129.28 kJ·mol/L, respectively. The proposed method is more simple and convenient than the current approaches based on the radical-chain reaction for studying alcohol oxidation.     

Energy flow between litter of Puccinellia tenuiflora community and soil microorganisms in Songnen Grassland in Northeast China

The energy flow process between litter of Puccinellia tenuiflora community and soil microorganisms has been studied and a compartment model established to discuss the characteristics and function of microorganism during decomposing litter. The results show that during the process of energy flow through microorganism, the energy input is 1357.84 kj'm^-2'a^-1; the energy absorbed by microorganism is 733.97 kj'm^-2'a^-1in which up to 552.29 kj'm^-2'a^-1 energy is consumed for respiration and the energy about 181.23kj'm^-2'a^-1 is formed for microorganism biomass. 95% of the litter accumulated on the ground annually would be decomposed in 1. 85 years and the decomposition index is 1. 93. The mathematical model of the energy x^( t) absorbed by microorganism of the year was described as x₂(i) = 733. 97 -0. 82e^-1.85t and the model of the energy x₂(t) formed for microorganism biomass of the year is expressed as x2( t) = 181.23 - 0. 37ee^-1.85t + 0.005ee^-4.05t. The equilibrium state of the energy absorbed by microorganism is 733.97 kJ'm^-2*a^-1 and the equilibrium state of the energy formed for microorganism biomass is 181.23 kj*m^-2*a^-1.     

Kinetic studies of the decom position reaction of adducts of dinuclear Fe( Ⅱ )/O2

Kinetic studies of the decomposition reaction of dinuclear Fe( Ⅱ ) adducts [Fe2(N-Et-HPTB){O2P(OPh)2}](CIO4)2 (1)and [Fe2(N-Et-HPTB) {O2P(Ph)2}] (CIO4)2 (2) with O2 have been carried out at low temperature using UV-vis spectra. The decomposition reaction of Fe( Ⅱ)/O2 adducts was first-order in the experimental conditions, and the activation parameters were obtained. △H￠ = 85.62 kJ @ mol-1, △S≠= 19.43 J @ mol-1 @ K-1 for compound (1) and △H￠ = 97.97 kJ @ mol-1,△S≠ = 55.68 J @ mol-1 @ K-1 for compound (2). These results are similar to those of dioxygen adducts of other metals complexes and natural enzymes such as methane monooxygenase (MMOH).     

亚铁联合不同氧化剂对石油烃污染场地热脱附废水的处理

采用亚铁（Fe²⁺）分别联合次氯酸钠（NaClO）、过硫酸钠（Na?S?O₈）和过氧化氢（H₂O₂） 3种氧化剂处理某原油浸染土壤的热脱附废水，考察了pH值、Fe²⁺投加量、氧化剂投加量和反应时间对处理效能的影响。Fe²⁺/H₂O₂和Fe²⁺/ Na?S?O₈均能有效去除热脱附废水中的典型污染物——石油烃物质，去除率分别达到100.0%和97.8%，但Fe²⁺/H₂O₂体系对化学耗氧量（COD）的去除效果明显优于Fe²⁺/Na?S?O₈。Fe²⁺/H₂O₂可将有机物彻底氧化分解，而Fe²⁺/NaClO和Fe²⁺/Na?S?O₈仅是将有机物氧化分解为中间物质。多元变量分析结果表明，pH值和氧化剂投加量是影响去除效果的主要因素，Fe²⁺/H₂O₂处理热脱附废水的吨水处理成本较高，但是综合效果最好；Fe²⁺/Na?S?O₈处理成本次之，但无法彻底降解COD；Fe²⁺/NaClO成本最低，但对有机物去除效果最差。综合去除效果和经济因素考量， Fe²⁺/H₂O₂体系更适用于处理热脱附废水。     

Synthesis and structure of Cu5(BTA)6(TTA)4 · 5DMF, a copper-nitrogen cluster containing η Π3-benzotriazolate

The title cluster compound—Cu₅(BTA)₆(TTA)₄·5DMF was prepared using thenyltrifluoroacetone and benzotriazolate ligands. The crystal structure indicates that a tetrahedral array of Cu(1), Cu(2), Cu(3) and Cu(4) ions surrounding a central Cu(5) ion are held together by bridging tridentate BTA^- and terminated by TTA^- bond cap. The three nitrogen atoms of a BTA^- bond three different copper ions to form a η³-benzotriazolate. The central Cu ion has a distorted octahedral structure and the surrounding Cu ions are 5 coordinated forming distorted tetragonal structures. The distances between the surrounding Cu(Ⅱ) ions and the central Cu(Ⅱ) ion are in the range of 0.3561—0.3755 nm and those between the surrounding Cu(Ⅱ) ions are in the range of 0.5785—0.6301 nm.     

Investigation of the cross-reaction mechanism of C<Subscript>6</Subscript>H<Subscript>5</Subscript>F-HNO<Subscript>2</Subscript> aqueous solution irradiated at 355 nm by transient absorbance spectrum technique

The transient absorption spectrum technique was employed to investigate the cross-reaction mechanism of C6H5F-HNO2 aqueous solution irradiated at 355 nm. The characteristic and the kinetic parameters of transient species were also detected. Hydroxyl radical derived from the photolysis of HNO2 was added to monofluorobenzene with a second-order rate constant of （5.83±0.17）×10^9 L·mol^-1·s^-1 to form an adduct, C6H5F…OH, which was able to react with HNO2 as the main reaction pathway with a rate constant of （8.3±0.1）×10^7 L·mol^-1·s^-1. The C6F6…OH adduct can also be decayed by elimination of H2O to yield monofluorophenyl radical C6H4F-. By GC-MS technique, the final products were identified to be monofluorophenol, nitro-monofluorobenzene, nitro-monofluorophenol and para-fluorobiphenyl.     

Synthesis, Characterization and Calorimetry of Ni（C4H8N2O3）2Cl2

A coordination complex was synthesized from NiCl2 and dipeptide glycylglycine（GG）. It was characterized by element analysis, NMR and TG methods, and then was determined to be Ni（C4HsN2O3）2Cl2. Using an isoperibolic reaction calorimeter, the standard molar enthalpy of formation of Ni（GG）2Cl2（solid） has been determined to be -（1 674.66±2.02） kJ · mol^-1 at 298.15 K.     

Standard molar enthalpy of formation of morin studied by rotating-bomb combustion calorimetry

Flavonols are plant pigments that are ubiquitous in nature. Morin and other related plant flavonols have come into recent prominence because of their usefulness as anticancer, anti-tumor, anti-AIDS, and other important therapeutic activities of significant potency and low systemic toxicity. The heat of combustion of morin (molecular formula, C₁₅H₁₀O₇·H₂O) in oxygen was measured by a rotating-bomb type combustion calorimeter, the standard molar enthalpy of combustion of morin at T = 298.15 K was determined to be Δ_c H _m^⦵ (C₁₅H₁₀O₇·H₂O, s) = −(5 937.99 ± 2.99) kJ · mol⁻¹. The derived standard molar enthalpy of the formation of morin in solid powder state at T = 298.15 K, Δ_f H _m^⦵ (C₁₅H₁₀O₇·H₂O, s), was −(1 682.12 ± 3.58) kJ · mol⁻¹, which provide an accurate data of the stability of morin to the pharmacy and pharmacology. Biography: HOU Hanna(1956–), female, Visiting researcher, Associate professor of Hubei University of Education, research direction: thermochemistry.     

Interaction of aloe-emodin with human serum albumin

The presence of several high affinity binding sites on human serum albumin (HSA) makes it a possible target for many drugs. This study is designed to examine the effect of aloe-emodin on HSA by fluo-rescence, CD spectroscopy and molecular modeling. The results of fluorescence measurements sug-gested that the hydrophobic interaction was the predominant intermolecular force stabilizing the AE-HSA complex, which was in good agreement with the result of molecular modeling study. And the enthalpy change ΔH0 and the entropy change ΔS0 were calculated to be -7.041 kJ·mol-1 and 76.619 J·mol-1·K-1 according to the Van't Hoff equation. The alterations of protein secondary structure in the presence of AE in aqueous solution were quantitatively calculated from CD spectra, and the content of α-helices obviously increased.     

Electrochemical properties of LiNi<Subscript>0.5</Subscript>Mn<Subscript>1.3</Subscript>Ti<Subscript>0.2</Subscript>O<Subscript>4</Subscript>/Li<Subscript>4</Subscript>Ti<Subscript>5</Subscript>O<Subscript>12</Subscript> cells

Spinel compounds LiNi_0.5Mn_1.3Ti_0.2O₄ (LNMTO) and Li₄Ti₅O₁₂ (LTO) were synthesized by different methods. The particle sizes of LNMTO and LTO are 0.5–2 and 0.5–0.8 μm, respectively. The LNMTO/LTO cell exhibits better electrochemical properties at both a low current rate of 0.2C and a high current rate of 1C. When the specific capacity was determined based on the mass of the LNMTO cathode, the LNMTO/LTO cell delivered 137 mA·h·g⁻¹ at 0.2C and 118.2 mA·h·g⁻¹ at 1C, and the corresponding capacity retentions after 30 cycles are 88.5% and 92.4%, respectively.     

Trend, seasonal and diurnal variations of atmospheric CO2 in Beijing

The concentration of atmospheric CO₂ in Beijing increased rapidly at a mean growth rate of 3.7% · a⁻¹ from 1993 to 1995. After displaying a peak of (409.7±25.9) μmol · mol⁻¹ in 1995, it decreased slowly. Both the almost stable anthropogenic CO₂ source and increasing biotic CO₂ sink contribute to the drop of CO₂ concentration from 1995 to 2000. The seasonal variation of CO₂ concentration exhibits a clear cycle with a maximum in winter, averaging (426.8±20.6) μmol · mol⁻¹, and a minimum in summer, averaging (369.1±6.1) μmol·mol⁻¹. The seasonal variation of CO₂ concentration is mainly controlled by phenology. The mean diurnal variation of atmospheric CO₂ concentration for a year in Beijing is highly clear: daily maximum CO₂ concentration usually occurs at night, but daily minimum CO₂ concentration does in the daytime, with a mean diurnal difference more than 34.7 μmol·mol⁻¹. It has been revealed that the interannual variations of atmospheric CO₂ concentration in winter and autumn regulated the interannual trend of atmospheric CO₂, whereas the interannual variation of CO₂ concentration in summer affected the general tendency of atmospheric CO₂ in a less degree.     

The giant magnetocaloric effect in Gd<Subscript>5</Subscript>Si<Subscript>2</Subscript>Ge<Subscript>2</Subscript> with low purity gadolinium

The giant magnetocaloric effect Gd5Si2Ge2 alloy was prepared with 99wt% low purity commercial Gd. Powder XRD and magnetic measurements showed that the Gd5Si2Ge2 alloy annealed at 1200℃ for 1h had a significant magnetic- crystallographic first order phase transition at about 270 K. The maximal magnetic entropy change is 17.55 J· kg^-1· K^-1 under a magnetic field change of 0-5 T. The distinct increase of magnetic entropy change belongs to the first-order phase transition from the orthorhombic Gd5Si4-type to the monoclinic Gd5Si2Ge2-type after high temperature heat-treatment.     

Theoretical study on the lithium bond interaction of furan homologues C4H4Y （Y=O,S） with LiCH3 via DFT and MP2

The optimizations geometries and interaction energy corrected by BSSE of the complexes between C4H4Y （Y=O, S） and CHiLi have been calculated at the B3LYP/6-311＋＋G^＊＊ and MP2/6-311＋＋G^＊＊ levels. Three complexes were obtained. Abnormally, the calculations showed that all the C10--Li14 bond lengths increased obviously but the blue-shift of C10-Li14 stretching frequency occurred after formed complexes. The calculated binding energy with basis set super-position error （BSSE） and zero-point vibrational energy corrections of complexes I-III is -45.757, -35.700 and -39.107 kJ·mol^-1, respectively. The analyses on the combining interaction with the atom-in-molecules theory （AIM） also showed that a relatively strong lithium bond interaction presented in furan homologues C4H4Y-LiCH3 systems. Natural bond orbital theory （NBO） analysis has been performed, and the results revealed that the complex I is formed with n-σ type lithium bond interaction between C4H40 and LiCH3, complex II is formed with TT-s type lithium bond interaction between C4H4O and LiCH3, and complex III is formed with TT-s and n-s type lithium bond interactions between C4H4S and LiCH3, respectively.     

Coordination behavior between zinc salts and L-α-methionine

The solubility properties of ZnCl\-2/ZnAc\-2/ZnSO\-4_Met_H\-2O systems at 25℃ in the whole cocentration range have been investigated by phase equilibrium method. The results indicate that ZnAc\-2 and ZnSO\-4 systems are both simple systems, which do not exist any compound; there are 2 complexes formed in ZnCl\-2 system: Zn(Met)Cl\-2 and Zn(Met)\-2Cl\-2·2H\-2O. Under the direction of phase equilibrium result, 2 solid complexes have been prepared in water and characterized by chemical analysis, IR, X_ray diffraction. Their combustion energies have also been determined by means of a RBC_type_1 rotating_bomb calorimeter, and their standard enthalpies of formation, Δ f, coor(s)H O-, have been calculated which are (-828.32±3.00) kJ·mol -1 and (-1 117.08±6.15) kJ·mol -1, respectively.     

Study on the reaction of carbon disulfide with hydroxyl radical in aqueous solution

Carbon disulfide is an important sulfur-containing compound in the environment, and its oxidation produces about 30% of the atmospheric COS[1]. In situ measure- ments show that CS2 is widespread in the sea surface wa- ters[2―4], and more recently, the continental water seems to be especially rich sources of CS2 due to industrial waste- water effluents. It is generally accepted that the ocean is an important source for atm. CS2, and Xie et al.[5] found that marine photochemical reaction of…