The leaching of chalcopyrite with ferric sulfate

The leaching kinetics of natural chalcopyrite crystals with ferric sulfate was studied. The morphology of the leached chalcopyrite and the electrochemical properties of chalcopyrite electrodes also were investigated. The leaching of chalcopyrite showed parabolic-like kinetics initially and then showed linear kinetics. In the initial stage, a dense sulfur layer formed on the chalcopyrite surface. The growth of the layer caused it to peel from the surface, leaving a rough surface. In the linear stage, no thick sulfur layer was observed. In this investigation, chalcopyrite leaching in the linear stage was principally studied. The apparent activation energy for chalcopyrite leaching was found to range from 76.8 to 87.7 kJ mol⁻¹, and this suggests that the leaching of chalcopyrite is chemically controlled. The leaching rate of chalcopyrite increases with an increase in Fe(SO₄)_1.5 concentration up to 0.1 mol dm⁻³, but a further increase of the Fe(SO₄)_1.5 concentration has little effect on the leaching rate. The dependency of the mixed potential upon Fe(SO₄)_1.5 concentration was found to be 79 mV decade⁻¹ from 0.01 mol dm⁻³ to 1 mol dm⁻³ Fe(SO₄)_1.5. Both the leaching rate and the mixed potential decreased with an increased FeSO₄ concentration. The anodic current of Fe(II) oxidation on the chalcopyrite surface in a sulfate medium was larger than that in a chloride medium.     

Cytology and microenvironment of somatostatin (D) cells in the gastric fundic mucosa of rodents

Somatostatin from gastric D-cells exerts an inhibitory effect upon the release of gastric acid, enzymes and gastrin. From previous investigations, a paracrine mode of action of somatostatin has been postulated. However, the exact route of the delivery of gastric somatostatin remains still uncertain and controversial. To obtain a closer view of fundic D-cells, the complete shapes and their microanatomical relationships to neighboring tissue elements were examined in immunostained serial semithin (0.5 mu m) sections of the fundic mucosa of rats, mice and golden hamsters, exemplarily by the combined utilization of computer-assisted 3D reconstructions. All the D cells examined in the present study were found to belong to the 'closed-type' of entero-endocrine cells lacking contiguity to the luminal surface. In their shape, the D cells in this region displayed an expressed 'pleomorphism'. A subpopulation of D cells, ovoid in shape, were thoroughly enclosed by single parietal cells. Most of the D cells appeared to be intimately juxtaposed to parietal cells and/or chief cells with their cell bodies or cytoplasmic processes, but simultaneously blood capillaries were regularly located in close vicinity to such D cells. Thus, somatostatin from the fundic D cells may act upon parietal cells and chief cells via both paracrine (direct cell to cell or diffusion) and endocrine (local circulatory system). The morphological heterogeneity of gastric fundic D cells may reflect certain functional states.     

A new model for evaluating the dynamic shear strength of rocks based on laboratory test data for earthquake-resistant design

The dynamic shear strength of rocks is required for the earthquake-resistant design of nuclear power plants in Japan.This research aims to propose a mathematical model for estimating the dynamic strength and to validate the model.Two different types of specimens were prepared for the model validation,and the monotonic and cyclic loading tests were conducted to obtain the mathematical model parameters.Subsequently,multistep cyclic loading tests were performed,followed by simulations using the mathematical model.The test results demonstrated that the dynamic shear strength exceeded the static shear strength,which agreed with previous researches.Furthermore,the dynamic shear strength calculated using the mathematical model was generally consistent with that obtained from the experimental data.     

FTY720 Reduces Lipid Accumulation by Upregulating ABCA1 through Liver X Receptor and Sphingosine Kinase 2 Signaling in Macrophages

Formation of foam cells as a result of excess lipid accumulation by macrophages is a pathological hallmark of atherosclerosis. Fingolimod (FTY720) is an immunosuppressive agent used in clinical settings for the treatment of multiple sclerosis and has been reported to inhibit atherosclerotic plaque development. However, little is known about the effect of FTY720 on lipid accumulation leading to foam cell formation. In this study, we investigated the effects of FTY720 on lipid accumulation in murine macrophages. FTY720 treatment reduced lipid droplet formation and increased the expression of ATP-binding cassette transporter A1 (ABCA1) in J774 mouse macrophages. FTY720 also enhanced the expression of liver X receptor (LXR) target genes such as FASN, APOE, and ABCG1. In addition, FTY720-induced upregulation of ABCA1 was abolished by knockdown of sphingosine kinase 2 (SphK2) expression. Furthermore, we found that FTY720 treatment induced histone H3 lysine 9 (H3K9) acetylation, which was lost in SphK2-knockdown cells. Taken together, FTY720 induces ABCA1 expression through SphK2-mediated acetylation of H3K9 and suppresses lipid accumulation in macrophages, which provides novel insights into the mechanisms of action of FTY720 on atherosclerosis.     

MR images of mycobacterial infection

With the progress of imaging technologies such as CT and MR imaging, we can obtain various informations from CT and MR images. Especially, thin-section high resolution CT (HRCT) provides very useful information for the diagnosis of mycobacterial infection and other diseases of pulmonary parenchyma. Advantages of MR images over HRCT are higher tissue contrast and multidirection capability. The T2-weighted images and Gd-DTPA enhanced T1-weighted images accurately reflect pathologic structure of the lesion. Therefore, MR images can add many useful findings to CT on the selected cases which are differentiation of tubercloma from lung cancer, chronic empyema from mesothelioma, aspergiloma from lung cancer and lymphadenopathy from lymph node metastasis. We describe the usefulness of MR images for diagnosing mycobacterial infection and its differentiation from other pulmonary diseases.     

Advanced energy-efficient house (HARBEMAN house) with solar thermal, photovoltaic, and sky radiation energies (experimental results)

An energy-independent residential house (‘HARBEMAN house’; Harmony BEtween Man And Nature), incorporating sky radiation cooling, solar thermal, and photovoltaic energies was built in Sendai, Japan during July, 1996. This paper reports monitored results of this house since September 1996 to date. The paper also presents simulation results for the HARBEMAN house and its results compared with the annual experimental data. The HARBEMAN house, which meets almost all the energy demands, including space heating and cooling, domestic hot water, electricity generated by photovoltaic cell and rainwater for standard Japanese homes. Sky radiation cooling, solar thermal/photovoltaic (PV), and underground coolness as well as rainwater and waste heat are utilized in combination. Annual variations of water temperature in the underground main tank, heating/cooling/domestic hot water demands, collected and emitted heats by the solar collector and sky radiator have been monitored.     

野外试验场场址土壤蒸发量的计算

为了确定野外试验场场址由地表向地下土壤渗入的水量,必须计算场址的地表蒸发量。在野外试验场安装了环境气象自然监装置,每１０分钟自动记录一次监测数据,观测历时二年多。将所获取和气象数据和有关参数用Ｐｅｎｍａｎ法,能量平衡法,失窃代法和湍流相关法四种方法计算了土壤蒸发量,计算结果表明,试验场址的土壤年蒸发量与降水量基本一致,在４００－６００ｍｍ／ａ之间。     

Fluid flow and heat transfer of natural convection at a slightly inclined,upward‐facing,heated plate

Natural convective flows over upward‐facing, inclined plates were investigated experimentally, with an emphasis on the role of opposing flows that appear over the plates inclined slightly from the horizontal line. The flow fields over the plates and the surface temperatures of the heated plates were visualized with both dye and a liquid‐crystal thermometry. The results showed that both the descending and ascending flows appeared over the plates when the inclination angles of the plates were less than 15°. The two flows collided with each other at a certain distance from the plate edge, and then detached from the plate to become a thermal plume. It was found that the above distance was determined solely by the inclination angles and was independent of sizes and heat fluxes of the plates. The local heat transfer coefficients of the plates were also measured. The results showed that the heat transfer from the plate was enhanced by the occurrence of the descending flows. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(5): 362–375, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10036     

Electrolytic reduction of Eu(III) to Eu(II) in acidic chloride solutions with titanium cathode

The feasibility of a rare earth separation process by electrolytic reduction of Eu(III) with a titanium cathode was examined by cathodic polarization characteristics of Eu(III) on a titanium electrode and batch-type electrolytic reduction of Eu(III) using a bipolar electrolytic cell in acidic aqueous solutions of EuCl₃. The reduction of Eu(III) started at a cathode potential of about −0.6 Vvs standard hydrogen electrode (SHE). The plateau current for the reduction of Eu(III) was observed at around −1.2 Vvs SHE, but a further decrease in cathodic potential resulted in a decrease in the reduction current, which was caused by the hydrolysis of Eu(III). The plateau current is a diffusion-limiting current in the reduction of Eu(III). In the batch-type electrolytic reduction of Eu(III) using a bipolar electrolytic cell, complete reduction of aqueous 0.1 kmol m⁻³ EuCl₃ solution with a current efficiency of over 0.6 could be achieved by keeping the catholyte pH at 2, to avoid hydrolysis of Eu(III). The final percent Eu(III) reduction of the solution from an industrial europium purification process, which contained other rare earths, was lower than that of a synthetic EuCl₃ single electrolyte solution probably because of a more significant hydrolysis of rare earth ions. However, the final percent reduction increased with decreasing reduction current, the concentration of rare earths, and the viscosity of solution.     

Heavy metals removal from automobile shredder residues (ASR)

The fate of heavy metals during a separation process for automobile shredder residues (ASR) was investigated. A washing method to remove heavy metals from the ASR was also investigated. Although the separation process was not designed for removal of heavy metals, but for the recovery of reusable materials, the heavy metal content in the ASR was efficiently decreased. The concentrations of Pb, Cr and Cd in ASR were effectively reduced by a nonferrous metals removal process, and the As concentration was reduced by the removal of light dusts during the separation process. Five heavy metals (As, Se, Pb, Cr, Cd) remaining in the ASR after the separation process satisfied the content criteria of the Environmental Quality Standards for Soil (EQSS), while the concentrations of As, Se, Pb in the leachate from the remaining ASR did not satisfy the elution criteria of the EQSS. After additional washing of the remaining ASR with a pH 1 acid buffer solution, the As, Se, and Pb concentrations satisfied the EQSS for elution. These results indicate that an ASR residue can be safely recycled after a separation process, followed by washing at acidic pH.