牙周袋内挥发性硫化物对牙周基础治疗效果的影响

目的:初步探讨牙周袋内挥发性硫化物(volatile sulphur compounds,VSC)水平与慢性牙周炎(chronic periodontitis,CP)炎症程度的关系及其对牙周基础治疗效果的影响。方法:选择25例CP患者(男13例、女12例,平均年龄35岁),在治疗前用金刚牙周诊断仪检测硫化物水平,并记录探诊深度、附着丧失、探诊出血等临床指标,基础治疗后3个月再次检查各项临床指标。结果:在治疗前,浅、中、深袋组的VSC阳性位点率分别为17.1%、52.3%、86.0%,各组间差异有显著性(P<0.001);各个水平级别的VSC在不同袋深组中均有分布,各组中VSC水平<1.0的位点占绝大多数,随着袋深的增加,高水平的VSC位点比例逐渐增高,差异有显著性(P<0.01)。治疗后,VSC阴性位点的各项临床指标均较治疗前有显著性改善;VSC阳性位点的临床指标虽较治疗前有改善,但探诊深度、附着丧失的改善均明显差于阴性位点。结论:VSC水平可以在一定程度上反映牙周的炎症程度,并影响牙周基础治疗的效果。VSC的检测可以作为评判牙周炎活动性及预后的辅助手段。

HPLC法测定大鼠肺组织中双(对-氟苄基)三硫醚及其降解产物的浓度

目的：建立一种测定大鼠肺组织中双（对-氟苄基）三硫醚（BFTS）及其降解产物双（对-氟苄基）二硫醚（BFDS）的RP—HPLC分析方法。方法：在0．2g大鼠肺组织中加入正己烷-异丙醇（95：5，v／v）5．0ml，11．50μg／ml内标（苄基二硫醚）溶液20μl，制成匀浆，离心后取上清液4．0ml，真空抽干，残渣加流动相（乙腈：水=65：35，v／v）150μl复溶，离心后取上清液进行HPLC分析。HPLC分析条件为：SB—C18柱，流动相为乙腈-水（65：35，v／v）；流速：1．0ml／min；柱温：30℃；检测波长：220nm；进样量：100μl。结果：BFTS和BFDS在0．04712～14．78μg／g（r=0．999）及0．04831～23．96μg／g（r=0．999）范围内呈线性关系，定量限分别为0．04712μg／g和0．04831μg／g，回收率分别为95．71％～107．2％和90．00％～110．5％，精密度RSD均小于10％。该方法已成功地用于大鼠静脉注射12．5mg／kg BFTS后，肺组织中BFTS及BFDS的含量测定。结论：该法准确、灵敏、可靠，可用于BFTS及BFDS的组织分布研究。

Kinetics of the Chlorination of Copper （I） Sulphide by Calcium Chloride in the Presence of Oxygen

The chemism of the chlorination of copper （I） sulphide by calcium chloride in the presence of oxygen has been determined based on the thermodynamic analysis in the Cu2S-CaCl2-O2 system as well as characterization of used raw materials and obtained products. The influence of temperature （from 473 to 773 K）, time （from 2 to 120 min）, oxygen flow （from 20 to 100 L/h） and calcium chloride quantity （from 5 to 40%） on the chlorination degree has been investigated. Kinetic analysis and the activation energy values of 20.89 kJ/mol showed that the chlorination of copper （I） sulphide by calcium chloride in the presence of oxygen is diffusion controlled.

Simultaneous Determination of Halogen Compounds and Sulfur Oxides in Flue Gas by Ion Chromatography

Ion chromatography （IC） is a suitable analytical method for the determination of anions. As analytical methods for the halogen compounds in flue gas, those of bromine compound, fluorine compound, chlorine （Cl2） and hydrogen chloride （HCI） are listed in JIS. However, IC has not been adopted in JIS except for HCI and C12. Because the carbon dioxide in flue gas is absorbed in a 0.1 M sodium hydroxide solution as an absorber, it is interfered with the measurement of F^- and Cl^- ions. This paper describes the development of the pretreatment equipment for the flue gas analysis by IC, and its applications to real flue gas analysis. The F^-, Cl^-, Br^- and SO4^2- in the absorbing solution can be clearly separated by IC using the pretreatment equipment. The halogen compounds and sulfur oxides in flue gas can be simultaneously determined by IC.

Effect of sodium pyrophosphate on the flotation separation of chalcopyrite from galena

The effect of sodium pyrophosphate （SPH） on the separation of chalcopyrite from galena was examined through flotation, adsorption, electrokinetic studies and infrared spectral analysis. Differential flotation tests indicate that satisfactory separation can be achieved within the pH range from 2.5 to 6 using SPH to depress the galena, but not the chalcopyrite when O-isopropyl-N-ethyl thionocarbamate （IPETC） is used as the collector. The electrophoretic mohilities of both the minerals dramatically become negatively charged following SPH adsorption in the pH range from 2.5 to 12, The infrared spectral analysis suggests that chemical adsorption occurs on galena surface treated by SPH, indicating that a chelate complex has formed. At weakly acidic pH values, the adsorption density of IPETC onto galena is significantly reduced in the presence of SPH. However, the amount of IPETC adsorbed onto chalcopyrite almost remains at the same level. Since the observed adsorption density of IEPTC onto chalcopyrite is quite high compared to galena, the observed flotation results are explained. A possible mechanism for the interaction between the two sulphide minerals and SPH is discussed.

The Chemical Principle of Green Coal Power

Coal is still a major source of energy, also a major source of SO_2, NOx and CO_2 emission though. Removal of SO_2 and NOx doubled the cost of power generation, and capture of CO_2 is equivalent to double the market price of power coal. The GCP （green coal power） is the power generated in coal-combustion with zero emission. The author indicates that it is possible to make coal-fired power plants emission free based on thermodynamic analysis and purposely designed experiments using SFG （simulated flue gases）. It is concluded in the study that all SO_2 and NOx in the post-combustion flue gas are reduced to inoffensive substances at temperature lower than 750 ℃ when contacting carbon and elemental sulfur is separated in succeeded cooling of flue gas at temperatures 200-400 ℃, and the ultrafine dusts are trapped in condensed water at temperature blow 100 ℃. Based on chemical engineering expertise the author is sure that the cost for removing acid gases is much lower than any clean coal technologies known to today. Instead of capture, the remained CO_2 is converted to CO in the second time contact with carbon at 900-950 ℃. CO is the raw material of chemical synthesis and, thus, CO_2 is stored in chemical products such as methanol, fertilizer, plastics, etc. The simple and low-cost processing allows GCP utilized in practice easily.

Electron Momentum Spectroscopy of Ethanethiol Complete Valence Shell

The binding energy spectra and electron momentum distributions for the complete valence orbitals of ethanethiol were measured for the first time by binary （e, 2e） electron momentum spectroscopy employing non-coplanar symmetric kinematics at an impact energy of 1200 eV plus binding energy. The experimental results are generally consistent with the theoretical calculations using density functional theory and Hartree-Fock methods with various basis sets. A possible satellite line at 17.8 eV in binding energy spectrum was observed and studied by electron momentum spectroscopy.

Preparation of the complex metallic oxides additive for naphtha sulfur reduction in FCC

The M/USY/Al2O3/kaolinite sulfur reduction additive systems containing vanadium were prepared by different methods. The influence of the preparation methods, the active constituent forerunners, the vanadium content and the type of molecular sieves on sulfur reduction of fluid catalytic cracking （FCC） gasoline were studied by a small fixed bed. The results showed that when FCC catalyst was blended with the sulfur reduction additives prepared by the special method at the ratio of 95：5, the relative sulfur reduction rate reached 35% and there was little influence on distribution of the products and quality of the gasoline. The XRD analysis indicated that the Y molecular sieve crystal structure in the additives prepared by the specific method retained integrity.

Metal sulfide quantum dots-aggregated PAMAM dendrimer for cadmium ion-selective electrode-based immunoassay of alpha-fetoprotein

An ion-selective electrode(ISE)-based immunoassay has been innovatively designed for the sensitive detection of liver cancer biomarker(alpha-fetoprotein,AFP),using metal sulfide quantum dot(QD)-based nano labels.Cd S QDs-aggregated PAMAM dendrimer(QD-DE)was first synthesized and functionalized with polyclonal rabbit anti-human AFP antibodies.Thereafter,a sandwich immunoreaction was implemented on monoclonal mouse anti-human AFP antibody-coated microplate by using antibody-functionalized QD-DE as the secondary antibody.Accompanying the immunocomplex,subsequent potentiometric detection of cadmium ion dissolved from the QD-DE under acidic condition was conducted on a portable cadmium ion-selective electrode(Cd-ISE).Results revealed that the electrode potential of the Cd-ISE increased with the increment of AFP concentration from 0.1 to 100 ng m L^(-1)at a detection limit(LOD)of 68 pg m L^(-1).The relative standard deviations(RSD)were below9.09%and 10.54%for the intra-and inter-assay,respectively.Additionally,six human serum specimens were determined on CdISE-based immunosensor by using commercial human AFP ELISA kit as the reference,and gave good relationship between two methods.Importantly,Cd-ISE-based immunoassay offers the promise for simple and cost-effective screening of disease-related biomarkers.

High precision in-situ Pb isotopic analysis of sulfide minerals by femtosecond laser ablation multi-collector inductively coupled plasma mass spectrometry

An in-situ microanalysis of Pb isotopic compositions in sulfide minerals is carried out by using femtosecond laser-ablation multi-collector inductively coupled plasma mass spectrometry （fsLA-MC-ICP-MS）. High-temperature-activated carbon was used to filter Hg contained in the carrier gas, which reduced the Hg background signal by 48% and also lowered the detection limit of the analysis. Fractionation and mass discrimination effects existing in the ICP-MS analytical processes were corrected using an internal reference T1 in conjunction with an external reference NIST SRM 610. The proposed method was used to an- alyze the Pb isotopic compositions of chalcopyrite, pyrite, and sphalerite from the Dulong Sn-Zn-In polymetallic ore district. The results showed that in this ore district, the sulfide minerals and different grains of the same sulfide mineral show a large variation in Pb content up to 1000-fold. The studied pyrites show relatively higher Pb contents and homogeneous Pb isotopic compositions, whereas the sphalerites have low Pb contents but most variable Pb isotopic compositions. It is suggested that the large variation of Pb isotopic composition may reflect a late hydrothermal superimposition on the primary sulfide formation. In addition, radiogenic Pb accumulated by radioactive decay of trace amounts of U over time in the host minerals may also be one of the causes for the large variation range of Pb content and Pb isotopic composition of those low-Pb sphalerites. Chalcopyrite and sphalerite grains with Pb content greater than 10 ppm presented a consistent Pb isotopic distribution, whereas all the sulfide grains with Pb content greater than 100 ppm had consistent Pb isotopic composition within 2s measurement uncertainties. The in-situ analysis of Pb isotopic composition agreed well with the results obtained by conventional chemical methods within 2s measurement uncertainties, indicating that the data obtained by fsLA-MC-ICP-MS are reliable. Additionally, this study indicates that the Pb isotopic composition could truthfully record the source of ore-forming minerals only for sulfide minerals with high Pb content. On the contrary, the Pb isotopic composition of low-Pb sulfide minerals may be affected by trace amounts of U in the host minerals that may lead to a highly radiogenic Pb isotope ratio. Alternatively, it is also possible that late fluid metasomatic overprinting may alter the Pb isotopic compositions.

Atomic process of oxidative etching in monolayer molybdenum disulfide

The microscopic process of oxidative etching of two-dimensional molybdenum disulfide(2D MoS_2) at an atomic scale is investigated using a correlative transmission electron microscope(TEM)-etching study.MoS_2 flakes on graphene TEM grids are precisely tracked and characterized by TEM before and after the oxidative etching. This allows us to determine the structural change with an atomic resolution on the edges of the domains, of well-oriented triangular pits and along the grain boundaries. We observe that the etching mostly starts from the open edges, grain boundaries and pre-existing atomic defects.A zigzag Mo edge is assigned as the dominant termination of the triangular pits, and profound terraces and grooves are observed on the etched edges. Based on the statistical TEM analysis, we reveal possible routes for the kinetics of the oxidative etching in 2D MoS_2, which should also be applicable for other 2D transition metal dichalcogenide materials like MoSe_2 and WS_2.