Isolation and identification of a high-efficiency hexavalent uranium adsorption strain and preliminary study of the influencing factors and adsorption mechanism.

In this study, a bacterial strain Chryseobacterium bernardetii WK-3 was isolated from the rhizosphere soil of a uranium tailings in Southern China. It can efficiently adsorb hexavalent uranium with an adsorption ratio of 92.3%. The influence of different environmental conditions on the adsorption ratio of Chryseobacterium bernardetii strain WK-3 was investigated, and the adsorption mechanism was preliminarily discussed by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS). The results showed that the optimal adsorption conditions for U(VI) by Chryseobacterium bernardetii strain WK-3 were pH = 5, temperature 30 ℃, NaCl concentration 1%, and inoculation volume 10%. When the initial concentration of U was 50 ~ 150 mg/L, the adsorption capacity of Chryseobacterium bernardetii strain WK-3 to U(VI) reached the maximum and maintained the equilibrium at 44 h. SEM-EDS results showed that phosphorus in cells participates in the interaction of uranyl ions, which may indicate that phosphate was produced during cell metabolism and was further combined to form U(VI)-phosphate minerals. In summary, Chryseobacterium bernardetii strain WK-3 would be a promising alternative for environmental uranium contamination remediation.

Tungsten oxide encapsulated phosphate-rich porous alginate composites for efficient U(VI) capture: Insights into synthesis, adsorption kinetics and thermodynamics.

In this work, novel monoclinic tungsten oxide (WO3)-encapsulated phosphate-rich porous sodium alginate (PASA) microspherical hydrogel beads were prepared for efficient U(VI) capture. These macroporous and hollow beads were systematically characterized through XRD, FTIR, EDX-mapping, and SEM-EDS techniques. The O and P atoms in the PO and monoclinic WO3 offered inner-spherical complexation with U(VI). The in situ growth of WO3 played a significant role inside the phosphate-rich biopolymeric network to improve its chemical stability, specific surface area, adsorption capacity, and sorption rate. The phytic acid (PA) served for heteroatom doping and crosslinking. The encapsulated WO3 mass ratio was optimized in different composites, and WO3/PASA3 (the microspherical beads with a mass ratio of 30.0 % w/w) exhibited remarkable maximum sorption capacity qm (336.42 mg/g) computed through the best-fit Langmuir model (R2 ≈ 0.99) and rapid sorption equilibrium, teq (150 min). The isothermal sorption studies were conducted at different temperatures (298, 303, and 308 K) and thermodynamic parameters concluded that the process of U(VI) sorption using WO3/PASA3 is endothermic and feasible having ΔHo (8.19 kJ/mol), ΔGo (-20.75, -21.38, and - 21.86 kJ/mol) and proceeds with a minute increase in randomness ΔSo (0.09 kJ/mol.K). Tungsten oxide (WO3)-encapsulated phosphate-rich porous microspherical beads could be promising material for uranium removal.

Piezoelectric hydrogel for treatment of periodontitis through bioenergetic activation.

The impaired differentiation ability of resident cells and disordered immune microenvironment in periodontitis pose a huge challenge for bone regeneration. Herein, we construct a piezoelectric hydrogel to rescue the impaired osteogenic capability and rebuild the regenerative immune microenvironment through bioenergetic activation. Under local mechanical stress, the piezoelectric hydrogel generated piezopotential that initiates osteogenic differentiation of inflammatory periodontal ligament stem cells (PDLSCs) via modulating energy metabolism and promoting adenosine triphosphate (ATP) synthesis. Moreover, it also reshapes an anti-inflammatory and pro-regenerative niche through switching M1 macrophages to the M2 phenotype. The synergy of tilapia gelatin and piezoelectric stimulation enhances in situ regeneration in periodontal inflammatory defects of rats. These findings pave a new pathway for treating periodontitis and other immune-related bone defects through piezoelectric stimulation-enabled energy metabolism modulation and immunomodulation.

Macroporous and ultralight polyethyleneimine-grafted chitosan/nano-TiO2 foam as a novel adsorbent with antibacterial activity for the efficient U(VI) removal.

The radioactive contamination from the excessive discharge of uranium-containing wastewater seriously threatens environmental safety and human health. Herein, macroporous and ultralight polyethyleneimine-grafted chitosan/nano-TiO2 composite foam (PCT) with antibacterial activity was synthesized, which could quickly remove U(VI) from solution. Among different PCT adsorbents, PCT-2 had the best adsorption performance for U(VI), which could be due to its honeycomb macroporous structures and the presence of abundant amino/imine groups. The kinetics and adsorption isotherms data were found in agreement with the pseudo-second-order model and the Langmuir model, respectively, indicating chemisorption or complexation as the main adsorption mechanism. The saturated adsorption capacity of PCT-2 for U(VI) reaches 259.91 mg/g at pH 5.0 and 298 K. The PCT-2 also presents good selectivity for U(VI) with the coefficient (ßU/M) order of Na+ > K+ > Mg2+ > Ca2+ > Ni2+ > Co2+ > Mn2+ > Al3+ > Fe3+ > Cu2+. The adsorption mechanism was explored using FT-IR and XPS analysis, indicating that amino/imine groups and hydroxyl groups are responsible for U(VI) complexation. Thermodynamic calculations show that U(VI) adsorption is endothermic and spontaneous. The ease of preparation, excellent adsorption performance and environmental friendliness of PCT-2 make it a novel adsorbent with antibacterial activity for radioactive contamination control.

Polyethyleneimine incorporated chitosan/α-MnO2 nanorod honeycomb-like composite foams with remarkable elasticity and ultralight property for the effective removal of U(VI) from aqueous solution.

The development of new adsorbents is needed to address the environmental challenges of radioactive wastewater treatment. Herein we reported a novel polyethyleneimine incorporated chitosan/α-MnO2 nanorod honeycomb-like composite (PCM) foam with remarkable elasticity and ultralight property for U(VI) removal. Among different PCM sorbents, PCM-40 possessed the highest sorption capacity for U(VI) due to its highly developed macroporous structure and high content of amine/imine groups. The kinetics were well-simulated by the pseudo-second-order model, indicating chemisorption as the rate-controlling step. The isotherms could be described by the Langmuir model, suggesting mono-layer homogeneous sorption of U(VI). The maximum sorption U(VI) capacity for PCM-40 reaches up to 301.9 mg/g at pH 4.5 and 298 K. The thermodynamic parameters revealed the spontaneous and endothermic nature of the adsorption process. The main sorption mechanism is related to the complexation of uranyl ions with the amine/imine and hydroxyl groups. The high sorption capacity, fast kinetic rate and relatively good selectivity of PCM-40 highlights its promising application in radioactive pollution cleanup.

Naringin Promotes Osteogenic/Odontogenic Differentiation of Dental Pulp Stem Cells via Wnt/ß-Catenin.

Purpose: This investigation intended to unravel the effect and mechanism of naringin on the proliferation and osteogenic differentiation of human dental pulp stem cells (hDPSCs). Methods: hDPSCs were induced to differentiate, and the degree of cell differentiation was observed by alizarin red staining, Oil Red O staining, and Alcian blue staining. hDPSCs were treated with 0, 20, 40, and 80 µmol/L naringin for 48 h, respectively. The proliferation rate and chemotaxis of the cells were measured by MTT and transwell assay, alkaline phosphatase (ALP) activity and osteogenic differentiation degree by ALP staining and alizarin red staining, and gene expression of osteogenic markers by qRT-PCR. Additionally, western blot was performed to test the levels of Wnt/ß-catenin signaling-related proteins in hDPSCs. Results: The isolated hDPSCs with spindle-shaped morphology had good differentiation capability. Further experiments confirmed naringin-caused increases in the proliferation rate and migration ability of hDPSCs. In addition, compared with the control group, naringin-treated cells had strong ALP activity and ossification levels and higher expression of Runx2, OPN, DSPP, and DMP1. The western blot results showed that naringin significantly activated Wnt/ß-catenin signaling in hDPSCs. Conclusion: Taken together, naringin enhances the proliferation, migration, and osteogenesis of hDPSCs through stimulating Wnt/ß-catenin signaling pathway.

Selective biosorption of U(VI) from aqueous solution by ion-imprinted honeycomb-like chitosan/kaolin clay composite foams.

The radioactive pollution caused by the discharge of radioactive wastewater poses a serious threat to public health and ecosystem stability owing to its long-term detriments. Herein, the ion-imprinted honeycomb-like chitosan/kaolin clay (ICK) composite foams were successfully fabricated and applied to the selective biosorption of U(VI) from aqueous solution. It was found that the ICK-2 was the best among various ICK foams owing to its well-developed honeycomb-like structure and the presence of abundant functional groups. As compared to the non-imprinted sorbent (NICK-2), the ion-imprinted sorbent (ICK-2) presents higher sorption and better selectivity since it can smartly recognize the target ions. The sorption isotherms was well-fitted with Langmuir model, and the maximum sorption capacity of ICK-2 was evaluated as 286.85 mg/g for U(VI) at 298 K and pH 5.0. The kinetic data could be described by pseudo-second order model. The FTIR and XPS results suggest that both amine and hydroxyl groups are responsible for U(VI) coordination. The ICK-2 presents high sorption capacity, good selectivity and fast kinetic rate, and thus it has potential application for U(VI) separation from radioactive wastewater.

Release behavior and mechanism of uranium and thorium from Ta-Nb tailings under simulated rainfall in Jiangxi Province, China.

Tantalum-niobium ore belongs to associated radioactive ore, which is accompanied by a certain amount of radioactive uranium and thorium. The remaining slag is enriched with a large number of radionuclides; after weathering, natural rainfall, and surface water scouring, radioactive elements such as uranium, thorium, and some heavy metal elements are exposed or washed into the soil, which poses a threat to the ecological environment and human health. In this study, for characterization analysis during, before, and after leaching, dynamic simulation experiment was carried out on a Ta-Nb slag sample in Jiangxi, China. From SEM analysis, the soluble substances adsorbed on the slag surface dissolve into the solution after leaching in simulated rainfall, and the remained slag becomes smooth with different particle sizes. The XRD diffraction analysis of the sample showed that after leaching in simulated rainfall, the existing forms of elements are different. pH of the leachate of Ta-Nb slag is 1.79; Ta-Nb slag contains many rare metal elements, nonmetal elements, radioactive elements, and some salt compounds; and the content of thorium is higher than that of uranium by EDS analysis. The release of uranium and thorium is obviously affected by the amount of leachate and pH. Under the lower pH of leaching solution, the release of uranium and thorium is more effective. The results of Fick diffusion theory and Elovich equation show that the release and migration mode of uranium and thorium in Ta-Nb slag are mainly surface elution; under acidic conditions, the release and migration of uranium and thorium are faster. This study provides basic data and scientific information for solving the key problems of pollution control of associated radioactive waste in environmental protection.

Cell-Traction-Triggered On-Demand Electrical Stimulation for Neuron-Like Differentiation.

Electromechanical interaction of cells and extracellular matrix are ubiquitous in biological systems. Understanding the fundamentals of this interaction and feedback is critical to design next-generation electroactive tissue engineering scaffold. Herein, based on elaborately modulating the dynamic mechanical forces in cell microenvironment, the design of a smart piezoelectric scaffold with suitable stiffness analogous to that of collagen for on-demand electrical stimulation is reported. Specifically, it generated a piezoelectric potential, namely a piezopotential, to stimulate stem cell differentiation with cell traction as a loop feedback signal, thereby avoiding the unfavorable effect of early electrical stimulation on cell spreading and adhesion. This is the first time to adapt to the dynamic microenvironment of cells and meet the electrical stimulation of cells in different states by a constant scaffold, diminishing the cumbersomeness of inducing material transformation or trigging by an external stimulus. This in situ on-demand electrical stimulation based on cell-traction-mediated piezopotential paves the way for smart scaffolds design and future bioelectronic therapies.

Electroactive Biomaterials and Systems for Cell Fate Determination and Tissue Regeneration: Design and Applications.

During natural tissue regeneration, tissue microenvironment and stem cell niche including cell-cell interaction, soluble factors, and extracellular matrix (ECM) provide a train of biochemical and biophysical cues for modulation of cell behaviors and tissue functions. Design of functional biomaterials to mimic the tissue/cell microenvironment have great potentials for tissue regeneration applications. Recently, electroactive biomaterials have drawn increasing attentions not only as scaffolds for cell adhesion and structural support, but also as modulators to regulate cell/tissue behaviors and function, especially for electrically excitable cells and tissues. More importantly, electrostimulation can further modulate a myriad of biological processes, from cell cycle, migration, proliferation and differentiation to neural conduction, muscle contraction, embryogenesis, and tissue regeneration. In this review, endogenous bioelectricity and piezoelectricity are introduced. Then, design rationale of electroactive biomaterials is discussed for imitating dynamic cell microenvironment, as well as their mediated electrostimulation and the applying pathways. Recent advances in electroactive biomaterials are systematically overviewed for modulation of stem cell fate and tissue regeneration, mainly including nerve regeneration, bone tissue engineering, and cardiac tissue engineering. Finally, the significance for simulating the native tissue microenvironment is emphasized and the open challenges and future perspectives of electroactive biomaterials are concluded.

Macroporous ion-imprinted chitosan foams for the selective biosorption of U(VI) from aqueous solution.

The radiological toxicity of uranium in nuclear industrial wastewater poses a long-term threat to environment, thus the effective separation of radionuclide from wastewater is very important for environmental safety. Herein, the macroporous ion-imprinted chitosan foams (ICFs) were synthesized by the combination of the facile freezing-drying and ion-imprinting techniques. Compared with non-imprinted chitosan foam, the ICFs showed much higher adsorption capacities (qm = 248.9-253.6 mg/g) and better adsorption selectivity for U(VI) owing to their smart recognition of the target ions for matching the cavities formed during U(VI)-imprinting process. The adsorption kinetics could be fitted by pseudo-second-order model; whereas the adsorption isotherms could be described by Langmuir model, indicating chemisorption or complexation mechanism. The FT-IR and XPS analysis further confirms that the coordination between U(VI) and the active sites (amine and hydroxyl groups) is the main adsorption mechanism. The thermodynamic parameters suggest that the adsorption of U(VI) is endothermic and spontaneous. This work provides new insights for the design of novel macroporous biosorbents with both high adsorption capacity and excellent adsorption selectivity for U(VI) biosorption from wastewater.

Preparation of porous chitosan/carboxylated carbon nanotube composite aerogels for the efficient removal of uranium(VI) from aqueous solution.

The porous chitosan/carboxylated carbon nanotubes composite aerogels (CS-CCN) with different CCN contents were prepared for the efficient removal of U(VI) from aqueous solution. The successful formation of CS-CCN aerogels with highly porous structure was confirmed by different characterizations (such as SEM, TEM, XRD, etc.). The sorption capacity of the aerogels depends on CCN content, which has significant impact on the porous structure and the sorption ability of the aerogels. The CS-CCN aerogels were found to be very effective for U(VI) sorption: the maximum mono-layer sorption capacity for CS-CCN2 aerogel reached 307.5 mg/g at pH 5.0 and 298 K. The chemisorption or surface complexation through sharing of O/N lone pair electrons on the active sites (carboxylic and amine groups) was responsible for U(VI) sorption, which is confirmed by the IR and XPS analysis. Meanwhile, the good-fitting of both sorption kinetics by pseudo-second-order model and sorption isotherms by Langmuir model also indicates chemisorption mechanism. The thermodynamic data suggest that U(VI) sorption on CS-CCN aerogel is endothermic and spontaneous. The unique characteristics such as high sorption capacity, fast kinetic, and easy recovery from solution make CS-CCN aerogels be very efficient sorbents for the treatment of radioactive wastewater.

[Determination of forbidden and restricted pesticides in Angelicae Sinensis Radix].

The present study is to establish a method for simultaneous determination of 50 kinds of pesticides in Angelicae Sinensis Radix by using liquid chromatography tandem mass spectrometry. The forbidden,restricted and customary pesticides were picked out as detecting indexes according to the principals of risk management. The factors affecting the extraction,purification,and detection were optimized,and the final condition was established as follows: the samples were extracted with acetonitrile. The separation of target compounds were performed by liquid column,and quantitative analysis was carried out by LC-MS/MS with MRM model. The calibration curves were linear in the range of 1-100 µg·L~(-1) with correction coefficients of greater than 0. 990. The recoveries of more than 93. 9%pesticides were ranged from 60% to 140% at three spiked levels. The detecting indexes in the method cover most forbidden and restricted pesticides,which is meaningful for the safety supervision of the Angelicae Sinensis Radix. With the advantage of rapidness and accuracy,this method can be used for routine determination of multi-pesticides in Angelicae Sinensis Radix.

Absorption of Codonopsis pilosula Saponins by Coexisting Polysaccharides Alleviates Gut Microbial Dysbiosis with Dextran Sulfate Sodium-Induced Colitis in Model Mice.

OBJECTIVES: Inflammatory Bowel Disease (IBD) is an autoimmune disease, and the gut microbiota has become a new therapeutic target. Herbal medicine (HM) has shown good efficacy in the clinical treatment of IBD; however, the synergistic actions of the dominant chemicals in HM decoctions are unclear. METHODS: In this study, we explored whether the complicated interconnections between HM and the gut microbiota could allow crosstalk between HM ingredients. Saponins and polysaccharides, i.e., the dominant chemicals in the Codonopsis pilosula Nannf (CPN) decoction, were investigated in a dextran sulfate sodium- (DSS-) induced mouse model. Bacterial 16S rRNA sequencing analyzed the change of gut microbiota structure and diversity. Gas chromatography (GC) determined the content of short-chain fatty acids (SCFAs) in feces. ELISA detected the expression of proinflammatory and anti-inflammatory cytokines associated with TH17/Treg balance. UPLC-QTOF-MS technology combined with PKsolver software analyzed the absorption of the highest exposure for monomeric compounds of CPN saponins in serum. The results indicated that CPN polysaccharides showed prebiotic-like effects in mice with DSS-induced colitis by simultaneously stimulating the growth of three important probiotics, i.e., Bifidobacterium spp., Lactobacillus spp., and Akkermansia spp., and inhibiting the growth of pathogenic bacteria, including Desulfovibrio spp., Alistipes spp., and Helicobacter spp. Moreover, CPN polysaccharides improved intestinal metabolism, enhanced the production of short-chain fatty acids, upregulated the expression of anti-inflammatory cytokines and downregulated the secretion of proinflammatory cytokines correlated with Th17/Treg balance, promoted the absorption of certain CPN saponins in the serum, and stimulated recovery of the holistic gut microbiota. CONCLUSION: CPN polysaccharides have the good prebiotic properties and shown good application prospects in the prevention and treatment of acute colitis. These findings provide insights into the specific bacteria responsible for active, inactive biotransformation of HM ingredients and those that are altered by HM administration.

Thalamocortical dysconnectivity in paroxysmal kinesigenic dyskinesia: Combining functional magnetic resonance imaging and diffusion tensor imaging.

BACKGROUND: Paroxysmal kinesigenic dyskinesia is associated with macrostructural and microstructural abnormalities in the thalamus. OBJECTIVES: To examine functional and structural connectivity of thalamocortical networks in paroxysmal kinesigenic dyskinesia and to further investigate the effect of mutation of the proline-rich transmembrane protein 2 on thalamocortical networks. METHODS: Patients with paroxysmal kinesigenic dyskinesia (n = 20), subdivided into proline-rich transmembrane protein 2-mutated (n = 8) and nonmutated patients (n = 12) and healthy controls (n = 20) underwent resting-state functional MRI and diffusion imaging scan. The functional properties of correlations in neural activity (functional connectivity) and the structural properties of white matter probabilistic tractography (structural connectivity) were analyzed to characterize thalamocortical networks. Furthermore, the effect of proline-rich transmembrane protein 2 mutation on functional and structural connectivity of thalamocortical networks were examined using one-way analysis of variance among three groups. RESULTS: Patients had increased functional and structural connectivity between ventral lateral/anterior thalamic nuclei and a lateral motor area, as compared to controls. This functional connectivity positively correlated with disease duration. Interestingly, proline-rich transmembrane protein 2-mutated patients showed decreased functional connectivity and preserved structural connectivity, between mediodorsal nucleus and prefrontal cortex, compared to nonmutated patients and controls. CONCLUSIONS: Thalamomotor/premotor hyperconnectivity suggests abnormal communication between thalamus and motor cortex in patients. Furthermore, thalamoprefrontal hypoconnectivity in proline-rich transmembrane protein 2-mutated patients might indicate that proline-rich transmembrane protein 2 mutations result in inefficient thalamoprefrontal integration. Our findings facilitate a deeper understanding of the crucial role of thalamocortical dysconnectivity in the pathophysiological mechanisms of paroxysmal kinesigenic dyskinesia. © 2017 International Parkinson and Movement Disorder Society.

Salvianolic acid A inhibits calpain activation and eNOS uncoupling during focal cerebral ischemia in mice.

BACKGROUND: Salvianolic acid A (SAA) is obtained from Chinese herb Salviae Miltiorrhizae Bunge (Labiatae), has been reported to have the protective effects against cardiovascular and neurovascular diseases. HYPOTHESIS: The aim of present study was to investigate the relationship between the effectiveness of SAA against neurovascular injury and its effects on calpain activation and endothelial nitric oxide synthase (eNOS) uncoupling. STUDY DESIGN: SAA or vehicle was given to C57BL/6 male mice for seven days before the occlusion of middle cerebral artery (MCAO) for 60min. METHODS: High-resolution positron emission tomography scanner (micro-PET) was used for small animal imaging to examine glucose metabolism. Rota-rod time and neurological deficit scores were calculated after 24h of reperfusion. The volume of infarction was determined by Nissl-staining. The calpain proteolytic activity and eNOS uncoupling were determined by western blot analysis. RESULTS: SAA administration increased glucose metabolism and ameliorated neuronal damage after brain ischemia, paralleled with decreased neurological deficit and volume of infarction. In addition, SAA pretreatment inhibited eNOS uncoupling and calpain proteolytic activity. Furthermore, SAA inhibited peroxynitrite (ONOO-) generation and upregulates AKT, FKHR and ERK phosphorylation. CONCLUSION: These findings strongly suggest that SAA elicits a neurovascular protective role through the inhibition of eNOS uncoupling and ONOO- formation. Moreover, SAA attenuates spectrin and calcineurin breakdown and therefore protects the brain against ischemic/reperfusion injury.

Microenvironment-Driven Bioelimination of Magnetoplasmonic Nanoassemblies and Their Multimodal Imaging-Guided Tumor Photothermal Therapy.

Biocompatibility and bioelimination are basic requirements for systematically administered nanomaterials for biomedical purposes. Gold-based plasmonic nanomaterials have shown potential applications in photothermal cancer therapy. However, their inability to biodegrade has impeded practical biomedical application. In this study, a kind of bioeliminable magnetoplasmonic nanoassembly (MPNA), assembled from an Fe3O4 nanocluster and gold nanoshell, was elaborately designed for computed tomography, photoacoustic tomography, and magnetic resonance trimodal imaging-guided tumor photothermal therapy. A single dose of photothermal therapy under near-infrared light induced a complete tumor regression in mice. Importantly, MPNAs could respond to the local microenvironment with acidic pH and enzymes where they accumulated including tumors, liver, spleen, etc., collapse into small molecules and discrete nanoparticles, and finally be cleared from the body. With the bioelimination ability from the body, a high dose of 400 mg kg(-1) MPNAs had good biocompatibility. The MPNAs for cancer theranostics pave a way toward biodegradable bio-nanomaterials for biomedical applications.

Structure-based Inhibitor Design for the Intrinsically Disordered Protein c-Myc.

Intrinsically disordered proteins (IDPs) are associated with various diseases and have been proposed as promising drug targets. However, conventional structure-based approaches cannot be applied directly to IDPs, due to their lack of ordered structures. Here, we describe a novel computational approach to virtually screen for compounds that can simultaneously bind to different IDP conformations. The test system used c-Myc, an oncoprotein containing a disordered basic helix-loop-helix-leucine zipper (bHLH-LZ) domain that adopts a helical conformation upon binding to Myc-associated factor X (Max). For the virtual screen, we used three binding pockets in representative conformations of c-Myc370-409, which is part of the disordered bHLH-LZ domain. Seven compounds were found to directly bind c-Myc370-409 in vitro, and four inhibited the growth of the c-Myc-overexpressing cells by affecting cell cycle progression. Our approach of IDP conformation sampling, binding site identification, and virtual screening for compounds that can bind to multiple conformations provides a useful strategy for structure-based drug discovery targeting IDPs.

Pharmacokinetic, tissue distribution and excretion of ginsenoside-Rd in rodents.

Ginsenoside-Rd (GS-Rd) is one of the major active components of Panax ginseng, and was shown to have the protective effects against several insults. However, we still lack some basic knowledge of GS-Rd, including its pharmacokinetic, tissue distribution and excretion in vivo in experimental animal, such as mice and rats. In this study, HPLC and radioactive tracer assays were performed to determine pharmacokinetic, tissue distribution and excretion of GS-Rd in rodents. After intravascular administration with 20, 50 or 150 mg/kg GS-Rd, the dynamic changes of GS-Rd concentrations in plasma were consistent with a two-compartment model while the concentration of ³H-labeled GS-Rd was rapidly reached the peak in plasma, and distributed to various tissues, among which the highest concentration was observed in the lung.

Effect of temperature on iron leaching from bauxite residue by sulfuric acid.

Bauxite residue, as solid waste from alumina production, contains mainly hematite [Fe2O3]. Kinetic study of iron leaching of bauxite residue by diluted sulfuric acid at atmospheric pressure has been investigated. The results have been obtained as following: (i) Temperature play an important role in iron leaching from bauxite residue. Higher temperature is favor of Fe(III) leaching from bauxite residue. (ii) The leaching process is applicable to the intra-particle diffusion model and the apparent activation energy of model of leaching is found to be 17.32 kJ/mol.