The effects of various activators on flotation performance of lime-depressed pyrrhotite

The effects of various activators on the flotation behaviour of lime-depressed pyrrhotite (FeS_1.1) were investigated. The activation mechanisms were studied using electrochemical analysis, Fourier transform infrared spectroscopy, zeta potential measurements, and X-ray photoelectron spectroscopy. Micro-flotation results showed that the floatability of pyrrhotite declined sharply from 97.6% to 5.1% with the addition of lime. The flotation performance improved with the addition of both acid and salt activators; oxalic acid was the best activator, with a recovery > 97.0%. Ca- and Fe-based hydrophilic films formed on the lime-depressed pyrrhotite surface, preventing the adsorption and oxidation of the collector on the pyrrhotite surface. The activator increases its own surface potential to prevent the production of hydrophiles, and also removed hydrophiles from the pyrrhotite surface. In addition, the oxalic acid formed a stable chelate and removed hydrophilic material from the pyrrhotite surface. This study contributes to understanding the flotation mechanism and activation of lime-depressed pyrrhotite.     

The Goettingen "Pro-Stab" removable plate system. A retrospective cephalometric study of the effects of a new Class II treatment appliance

The new removable double-plate appliance has characteristics which provide for efficient treatment of Class II malocclusions: virtually unimpaired speaking and free breathing seem to support patient compliance. The sagittal activation is easy to change and the plates for the upper and the lower jaw can be worn separately or in combination, with and without the "Pro-Stab" rods even with different wearing hours (modular concept). Evaluation of lateral head films taken at the beginning and at the end of treatment (mean interval 1.45 years) of 40 patients provided information on therapy-induced changes, which were then compared with results of recent publications. The data obtained with the new system indicate similar results as with bite-jumping appliances and headgear-supported activators. Inhibition of the sagittal development of the upper jaw and retrusion of the upper incisor segment have been primarily responsible for the correction of Class II malocclusions. The effect as regards the sagittal position of the lower jaw has been moderate. In comparison with similar appliances, protrusion of the lower incisors was more pronounced when treated with the Goettingen Type I "Pro-Stab" removable plate system.     

离子束辅助沉积对TiAlSiN薄膜性能的影响

分别利用真空电弧沉积技术与等离子体辅助真空电弧沉积技术在不锈钢片、高速钢片和单晶硅片上沉积TiAlSiN多元薄膜，通过X射线衍射和扫描电镜对采用两种方法制备的薄膜物相及表面形貌进行了分析比较，测定了高速钢片上薄膜的显微硬度，进行了耐磨性实验。结果表明，采用离子束辅助沉积制备的薄膜，有（200）面的择优取向，薄膜的表面形貌得到改善，硬度和耐磨性提高。     

喷雾热蒸发炭膜用于二次锂离子电池负极的研究

以有机热解炭(石墨)为原料,用喷雾热蒸发法制备了用于二次锂离子电池负极的炭膜,用循环伏安法和恒电流充放电法测试了所获炭膜的电化学性能,测试结果表明,在第1循环周期中存在1个还原峰对应在电极表面形成固体电解质中间相膜;当充放电电流大小合适时,容量和每mol炭中嵌入其他物质的摩尔数(x)值都较大,基于这些实验结果,认为所获得的炭膜能用作电池负极以相对测试其他正极材料的电化学性能。     

Structure and Some Properties of Pb(Zr,Ti)O 3 Thin Films

The possibility of obtaining Pb(Zr,Ti)O₃ (PZT) films by oxidation of Pb ― Zr ― Ti layers was investigated. The films were obtained by vacuum evaporation on a polished SiO₂ or glassceramics at 300-800 K. The PZT films obtained at 500 K were amorphous. With a rise in the condensation temperature to 600 K, film crystallization occurred in the perovskite structure. The dielectric and optical properties of PZT films were investigated. For metal ― dielectric ― metal (MDM) structures based on PZT films with a thickness of 0.8 μm, the capacity was 2.60 μF, which corresponds to a value of the dielectric constant of about 74,880. The energy-gap width determined by the short-wave boundary of self-absorption was equal to 3.5 eV. The advantages of the proposed method for obtaining PZT films are low deposition temperatures and the possibility of performing all technology in one cycle, including modification of the composition and properties of the films by doping.     

Blood compatibility of amorphous titanium oxide films synthesized by ion beam enhanced deposition

Titanium oxide films were synthesized on titanium, cobalt alloy and low-temperature isotropic pryolytic carbon by ion beam enhanced deposition. The non-stoichiometrical titanium oxide films were obtained. Blood compatibility of the films were evaluated by clotting time measurement, platelet adhesion investigation and hemolysis analyses. The results revealed that blood compatibility of the materials was improved by the coating of titanium oxide films. Semiconductor nature of non-stoichiometric titanium oxide films might be responsible for the improvement of blood compatibility.     

The serpin PAI-1 inhibits cell migration by blocking integrin alpha V beta 3 binding to vitronectin

During wound healing, migrating cells increase expression of both the vitronectin receptor (VNR) integrins and plasminogen activators. Here we report that vitronectin significantly enhances the migration of smooth muscle cells (SMCs), and that the specific VNR alpha V beta 3 is required for cell motility. We also show that the alpha V beta 3 attachment site on vitronectin overlaps with the binding site for plasminogen activator inhibitor (PAI)-1, and that the active conformation of PAI-1 blocks SMC migration. This effect requires high-affinity binding to vitronectin, and is not dependent on the ability of PAI-1 to inhibit plasminogen activators. Formation of a complex between PAI-1 and plasminogen activators results in loss of PAI-1 affinity for vitronectin and restores cell migration. These data demonstrate a direct link between plasminogen activators and integrin-mediated cell migration, and show that PAI-1 can control cell-matrix interactions by regulating the accessibility of specific cell-attachment sites. This indicates that the localization of plasminogen activators at sites of focal contact does not initiate a proteolytic cascade leading to generalized matrix destruction, but instead is required to expose cryptic cell-attachment sites necessary for SMC migration.     

Langmuir films from antibodies based on amphiphilic polyelectrolytes

A technique for forming Langmuir films from antibodies based on an amphiphilic polyelectrolyte was developed. The physicochemical and immunochemical properties of the Langmuir films obtained were studied. The interaction of HBsAg with the films was found to be described by a model with one binding site, whereas that of HBsAg with antibodies adsorbed on a polystyrene plate, by a model with a positive cooperativity. The use of the novel Langmuir films from antibodies increases the sensitivity of the immunoenzyme assay.     

Allosteric interactions between the membrane-bound acetylcholine receptor and chemical mediators: equilibrium measurements

An approach to equilibrium dialysis measurements has been developed which enables one to study the interaction of chemical mediators with the membrane-bound acetylcholine receptor and to gain information of a type previously obtainable only with soluble proteins. Equilibrium dialysis experiments conducted at pH 7.0,4 degrees C, and mu = 0.18 M, with electroplax membrane preparations from Electrophorus electricus revealed apparently homogeneous binding isotherms for decamethonium with dissociation constants in the range of 0.2-0.4 muM. The following new information has been obtained. (1) The activators of neural transmission, decamethonium and carbamylcholine, occupy overlapping binding sites. (2) These activators and the inhibitors, alpha-bungarotoxin and d-tubocurarine, compete for only one-half of the sites available to them even through the stoichiometry of these is 1:1 as measured with decamethonium (a reversibly binding activator) and alpha-bungarotoxin (an irreversible specific inhibitor). Different receptor molecules, preexisting nonequivalent binding sites, or an allosteric mechanism involving ligand-induced conformational changes are often considered to account for such observations.     

Fabrication and Magnetic Properties of Highly Oriented ZnO:Eu Films by Sol-Gel Process

A series of Eu-doped ZnO films were prepared by a sol-gel method. Precursor and films were characterized by thermal analysis (TG-DTA), X-ray diffraction (XRD), scanning electron microscope (SEM), UV-vis spectra, as well as the magnetism measurement. The wurtzite structure of obtained films presents an extreme high c-orientation character. The film susceptibility resembles a Curie-Weiss behavior at high temperature, and presents an obvious enhancement at low temperature, indicating the presence of antiferromagnetic interactions in the Zn0.9Eu0.1O films.     

Fe离子注入二氧化钛复合薄膜制备及光吸收性能研究

采用溶胶凝胶法在石英基体上制备了纯TiO2薄膜,并通过离子注入方法对TiO2薄膜进行Fe掺杂改性以促进TiO2薄膜光吸收边红移,提高其光吸收性能。利用XRD、XPS及UV-vis对不同注入剂量的Fe掺杂TiO2复合薄膜的晶相结构、原子化学态以及光吸收性能进行了表征。XRD测试结果表明,溶胶凝胶法制得的TiO2薄膜为锐钛矿相,经Fe离子注入后,复合TiO2薄膜经退火后锐钛矿相消失,金红石相出现,因为Fe3+离子进入晶胞代替Ti4+,在TiO2基体形成铁的固溶体,结果氧空缺形成促进了TiO2从锐钛矿向金红石的转变;XPS测试结果表明,经过退火Fe在复合TiO2薄膜中以Fe和Fe3O4形式存在,说明Fe离子进入TiO2晶格取代Ti,但Fe及其氧化物晶体峰未在XRD上观测到,说明两者结晶程度不高,以非晶形态存在;通过对溶胶凝胶法制备的TiO2薄膜注入不同剂量Fe的复合薄膜的紫外-可见吸收光谱分析可知,由于复合薄膜中Fe3O4的存在,使复合薄膜紫外-可见光吸收边发生了红移,并随注入剂量增加红移增大,根据红移效果确定Fe的适宜注入剂量为1×1017 cm-2。     

某低品位难选白钨矿常温浮选试验研究

江西某白钨矿石含钨0.23%,原矿钨品位低、嵌布粒度较细、萤石含量高,是典型的白钨-方解石-萤石（或重晶石）型难选白钨矿.针对该难选白钨矿中有价金属钨无法有效回收的现状,对其进行了试验研究,结果表明,采用组合药剂（GYW＋731）做捕收剂,新型药剂WH做活化剂,实现了该低品位难选白钨矿的常温浮选,闭路试验获得了品位为35.11%,回收率为72.20%的钨精矿.     

Suppression of the voltage-gated K+ current of human megakaryocytes by thrombin and prostacyclin

We examined the effects of platelet activators and inhibitors of platelet function on the voltage-gated delayed rectifier K+ current of human megakaryocytes. We found that both the activators such as thrombin, the thrombin receptor peptide (TRP42-47) and ADP and the inhibitors such as prostacyclin suppressed the delayed rectifier current through two different mechanisms. The cAMP dependent protein kinase (A-kinase) inhibitor IP20 blocked the suppression of the delayed rectifier current by prostacyclin and failed to block the suppression by thrombin, TRP42-47 and ADP. The effects of IP20 suggest that the action of prostacyclin is mediated by A-kinase and the action of the three activators is not mediated by A-kinase. Pertussis toxin (PTX) an inhibitor of the inhibitory GTP-binding proteins (Gi) blocked the suppression of the delayed rectifier current by thrombin, TRP42-47 and ADP and failed to block the suppression by prostacyclin. The effects of PTX suggests that the action of the three activators is mediated by Gi or some other PTX-sensitive GTP-binding protein. We speculate that thrombin and other platelet activators that activate Gi may be suppressing the delayed rectifier current via a direct interaction of Gi or a subunit of it with the delayed rectifier potassium channel itself.     

利用Bi原子的调控作用制备快速有序的L10-FePt薄膜

利用磁控溅射的方法,在玻璃基片上制备了以不同厚度Bi作底层的FePt薄膜,然后经不同温度真空热处理,得到L10有序结构的FePt薄膜；同时,系统地研究了退火时间以及Bi底层的厚度对FePt薄膜的磁性能和微结构的影响.实验结果表明:利用Bi作底层,通过Bi原子在薄膜中的扩散作用可以有效地调控FePt薄膜的有序化程度,从而对薄膜的矫顽力进行控制；更重要的是,利用上述Bi原子对FePt原子有序化的调控作用,可以实现FePt原子的快速有序化,制备出能够快速有序的L10-FePt薄膜.     

某浸染型低硫低镍铂钯矿石选矿试验研究

某浸染型低硫低镍铂钯矿石,铂、钯元素在矿物中的分布广泛而微量,无法明确其主要载体矿物。重选、浸出和初步浮选试验结果表明,重选和浸出对铂、钯的回收效果均不理想,而浮选比较适合用于从该矿石中回收铂、钯。通过浮选试验研究,硫化钠和硫酸铜是较理想的活化剂,最终闭路试验得到了Pt+Pd品位大于50 g/t的铂钯精矿。     

Structure and Properties of TiO2-CeO2 Films Deposited on Soda-Lime Silicate Glass Substrates by R.F.Magnetron Sputtering

TiO2-CeO2 films were deposited on soda-lime glass substrates at different ratio of O2 to Ar (0.10, 0.15,0.20) by R. F. magnetron sputtering. The structure, surface composition, UV-visible spectrum of the films were measured by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and spectrometer. The results show that the films are amorphous, and the relative molar ratio of Ce to Ti is higher than that of the target at lower ratio of O2 to Ar. Only tetravalent Ti 4 and Ce 4 ions are present in the films, and the obtained TiO2 -CeO2 films appear good uniformity and high density. The films deposited on the glass can shield ultraviolet light without significant absorption of visible light.     

Autonomic regulation of melatonin synthesis through intrinsic glutaminergic systems in mammalian pineal glands]

Prospects for the search for thrombolytic compositions on the basis of short-term and long-term acting plasminogen activators were shown. These will be useful as potential ambulance remedies for effective prehospital treatment. Combined proteolysis by plasminogen activators with complementary action mechanisms and significantly different pharmacokinetic behavior was suggested for this purpose.     

Grain Size and Wettability of TiO2/SiO2 Photocatalytic Composite Thin Films

The uniform transparent TiO2/SiO2 photocatalytic composite thin films are prepared by sol-gel method on the soda lime glass substrates, and characterized by UV-visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), BET surface area, FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS). It was found that the addition of SiO2 to TiO2 thin films can suppress the grain growth of TiO2 crystal, increase the hydroxyl content on the surface of TiO2 films, lower the contact angle for water on TiO2 films and enhance the hydrophilic property of TiO2 films. The super-hydrophilic TiO2/SiO2 photocatalytic composite thin films with the contact angle of 0-° are obtained by the addition of 10%-20% SiO2 in mole fraction.     

Conley lecture. A profession of trust: reflections on a fundamental virtue

The RNA polymerase II holoenzyme is the form of polymerase recruited to promoters for protein-coding genes. Several targets of mammalian activators, previously called coactivators, turn out to be subunits of the holoenzyme which activators use to recruit and regulate the holoenzyme. Several of these newly identified holoenzyme components have been implicated in human disease.     

Phase formation and microstructure in sputter-deposited Ti-Mo-C and Ti-W-C thin films

Ti-Mo-C and Ti-W-C films were deposited by cosputtering from carbide targets in order to examine the phase formation, microstructure, and mechanical properties. A series of Ti-Mo-C films were deposited, with compositions ranging from TiC to Mo₂C. The X-ray diffraction (XRD) analysis showed that multiphase Ti-Mo-C films, containing the (Ti,Mo)C, Mo₂C, and Mo₃C₂ phases, were only obtained in highly Mo-rich films. The transmission electron microscopy (TEM) analysis showed a higher defect content in single-phase alloy Ti-Mo-C films in comparison to TiC alone. The hardness for most Ti-Mo-C films was in the range of 8 to 10 GPa, but even lower values were obtained in the multiphase films. Ti-W-C films deposited by cosputtering of TiC and WC formed only (Ti,W)C solid solutions. The X-ray photoelectron spectroscopy (XPS) analysis of peak positions showed that the W 4f _7/2 binding energy decreased with increasing W content. The hardness of most of the Ti-W-C coatings was in the range of 15 to 17 GPa; however, a sample with 40 pct W had a hardness of 29 GPa. The TEM analysis of this sample revealed an extremely small grain size and a higher film density. The high hardness of this specimen is attributed to Hall-Petch strengthening.