A new nanometer material, nanometer AlO（OH） loaded on the fiberglass with activated carbon fibers felt（ACF） as the carrier, was prepared by hydrolytic reaction for the removal of Cd（II） from aqueous solution usi...A new nanometer material, nanometer AlO（OH） loaded on the fiberglass with activated carbon fibers felt（ACF） as the carrier, was prepared by hydrolytic reaction for the removal of Cd（II） from aqueous solution using column adsorption experiment. As was confirmed by XRD determination, the hydrolysis production loaded on fiberglass was similar to the orthorhombic phase AlO（OH）. SEM images showed that AlO（OH） particles were in the form of small aggregated clusters. The Thomas model was applied for estimating the kinetic parameters and the saturated adsorption ability of Cd（II） adsorption on the new adsorbent. The results showed that the maximum adsorption capacity of Cd（II） was 128.50 mg·g^-1 and 117.86 mg·g^-1 for the adsorbent mass of 0.3289 g and the adsorbent mass of 0.2867 g, respectively. The elution experiment result indicated that the adsorbed Cd ions was easily desorbed from the material with 0.1 mol·L^-1 HCl solution. Adsorption-desorption cycles showed the feasibility of repealed uses of the composited material. The adsorption capacities were influenced by pH and the initial Cd（II） concentration. The amount adsorbed was greatest at pH 6.5 and the initial Cd（II） concentration of 0.07 mg·L^-1, respectively. Nanometer AlO（OH） played a major role in the adsorption process, whereas the fiberglass and ACF were assistants in the process of removing Cd（II）. In addition, the adsorption capacities for Cd（II） were obviously reduced from 128.50 mg·L^-1 to 64.28 mg·L^-1 when Pb ions were present because Pb ions took up more adsorption sites.展开更多
A facile one-step co-precipitation method was demonstrated to fabricate amorphous sulfurcontaining calcium phosphate （SCP） nanoparticles, in which the sulfur group was in-situ introduced into calcium phosphate. The ...A facile one-step co-precipitation method was demonstrated to fabricate amorphous sulfurcontaining calcium phosphate （SCP） nanoparticles, in which the sulfur group was in-situ introduced into calcium phosphate. The resulting SCP exhibited a noticeable enhanced performance for Pb（II） removal in comparison with hydroxyapatite （HAP）, being capable of easily reducing 20 ppm of Pb（II） to below the acceptable standard for drinking water within less than 10 min. Remarkably, the saturated removal capacities of Pb（II） on SCP were as high as 1720.57 mg/g calculated by the Langmuir isotherm model, exceeding largely that of the previously reported absorbents. Significantly, SCP displayed highly selective removal ability toward Pb（II） ions in the presence of the competing metal ions （Ni（II）, Co（II）, Zn（II）, and Cd（II））. Further investigations indicated that such ultra-high removal efficiency and preferable affinity of Pb（II） ions on SCP may be reasonably ascribed to the formation of rodlike hydroxypyromorphite crystals on the surface of SCP via dissolution-precipitation and ion exchange reactions, accompanied by the presence of lead sulfide precipitates. High removal efficiency, fast removal kinetics and excellent selectivity toward Pb（II） made the obtained SCP material an ideal candidate for Pb（II） ions decontamination in practical application.展开更多
A process of treatment for containing Cd 2+ wastewater by sulfate reducing bacteria with upflow anaerobic fluidized bed reactor has been studied. When the concentration of COD and Cd 2+ in the influent were...A process of treatment for containing Cd 2+ wastewater by sulfate reducing bacteria with upflow anaerobic fluidized bed reactor has been studied. When the concentration of COD and Cd 2+ in the influent were 270 5mg/L and 100mg/L respectively and hydraulic retention time was 4 hours, the removal rate of COD and Cd 2+ were higher than 73 8% and 99 8% respectively. The reactor can treat as high as 1000mg/L of concentration of Cd 2+ . The highest removal velocity rate of Cd 2+ reached 2999 1mg/(L·d). And the possible relationship between sulfate reducing bacteria and methanogenic bacteria was discussed.展开更多
Sawdust (SD) a very low cost material has been utilized as adsorbent material for the removal of Cd (II) from aqueous solutions after treatment with mono methylol urea (MMU) in the presence of zinc chloride as a catal...Sawdust (SD) a very low cost material has been utilized as adsorbent material for the removal of Cd (II) from aqueous solutions after treatment with mono methylol urea (MMU) in the presence of zinc chloride as a catalyst to form MMU-SD. The reaction of MMU-SD was carried out under different conditions including MMU/SD molar ratio, catalyst concentration, and reaction time and temperature. Adsorption studies have been carried out to determine the effect of agitation time, pH, adsorbent and adsorbate concentrations on the adsorption capacity of Cd (II) ions onto MMU-SD. Langmuir, Freundlich and Redlich-Peterson isotherm models were applied in the adsorption studies. The experimental data were analyzed using various sorption kinetic models. The removal processes of Cd (II) onto MMU-SD particles could be well described by the pseudo-second order model. The maximum adsorption capacity of Cd(II) onto MMU-SD was 909 mg/g. Similarly, the Freundlich constant 1/n value was 0.45.展开更多
A new 3D Cd(II) coordination polymer, [Cd(Hpidc)]n(1, H3 pidc = 2-(pyrid-2-yl)-1H-imidazole-4,5-dicarboxy acid), has been prepared and characterized by elemental analysis, IR spectra, PXRD, and single-crystal X-ray di...A new 3D Cd(II) coordination polymer, [Cd(Hpidc)]n(1, H3 pidc = 2-(pyrid-2-yl)-1H-imidazole-4,5-dicarboxy acid), has been prepared and characterized by elemental analysis, IR spectra, PXRD, and single-crystal X-ray diffraction. Compound 1 crystallizes in orthorhombic, space group Fdd2 with a = 22.833(9), b = 25.536(9), c = 7.437(3) A, V = 4336(3) A3, Z = 16, Dc = 2.105 Mg·m-3, μ = 2.025 mm-1, F(000) = 2656, and the final R = 0.0261 and w R = 0.0636. The structure determination reveals that 1 exhibits a rare 3D 3-connected lig net with a point symbol of(82·10). In addition, the solid state properties such as thermogravimetric analysis and luminescence of 1 were also studied.展开更多
This work examined the removal of Pb(II) using a chitosan derivative (SB, synthesized from benzaldehyde) assisted by a magnetic field. The adsorption capacity for Pb(II) was investigated. It was found that 1) the pH a...This work examined the removal of Pb(II) using a chitosan derivative (SB, synthesized from benzaldehyde) assisted by a magnetic field. The adsorption capacity for Pb(II) was investigated. It was found that 1) the pH and concentration of the ion solution, as well as exposure time and strength of magnetic field, affected the degree of adsorption;and 2) studies of the adsorption isotherms and kinetics of ions onto SB revealed that SB showed enhanced adsorption capacity towards Pb(II) ions in a magnetic field compared with magnetically untreated samples. The Langmuir and Freundlich isotherm were applied to describe the experimental adsorption, and the maximum adsorption capacity of SB for Pb(II) was 2.5040 mg/g, when assisted by a magnetic field of 480 kA/m.展开更多
Natural freshwater surface coatings(biofilms and associated minerals), which were developed in the Nanhu Lake, Changchun, P. R. China, were used as an efficient biosorbent for the removal of Cd(Ⅱ) from aqueous soluti...Natural freshwater surface coatings(biofilms and associated minerals), which were developed in the Nanhu Lake, Changchun, P. R. China, were used as an efficient biosorbent for the removal of Cd(Ⅱ) from aqueous solutions. The batch experiments were carried out to determine the adsorption properties of Cd(Ⅱ) onto the natural surface coatings. The classical Langmuir adsorption isotherm was applied to estimating the equilibrium coefficients of Cd(Ⅱ) adsorbed on the surface coatings. The results show that the maximum adsorption capacity of the surface coatings is 434.78 μmol Cd/m2(being equal to 0.17 mmol Cd/g of surface coatings or 10.38 mmol Cd/g Fe) and the Cd(Ⅱ) removal from solution media by the natural surface coatings was shown to be strongly affected by solution pH and ion strength. The resulted information also indicates that the maximum Cd removal efficiency(CRE) was determined to be approximately 90% at initial Cd mass concentration of 0.1 mg/L(the concentration limit of Cd (Ⅱ) in wastewaters for discharge in aquatic media in Chinese legislation), and the kinetic adsorption of Cd(Ⅱ) onto the surface coatings is fast with around 70% of the total adsorption-taking place in 150 min in solution under the controlled laboratory conditions (mineral salts solution with defined speciation, ionic strength 0.05 mol/L, and 25 ℃). With the advantage of high Cd adsorption capacity, the natural surface coatings appear to be a potentially effective biosorbent for the removal and recovery of Cd (Ⅱ) from polluted water.展开更多
A single-layer Artificial Neural Network (ANN) model was developed to predict the removal efficiency of Ni(II) ions from aqueous solution using shelled Moringa Oleifera seed (SMOS) powder. Batch experiments resulted i...A single-layer Artificial Neural Network (ANN) model was developed to predict the removal efficiency of Ni(II) ions from aqueous solution using shelled Moringa Oleifera seed (SMOS) powder. Batch experiments resulted into standardization of optimum conditions: biomass dosage (4.0 g), Ni(II) concentration (25 mg/L) volume (200 mL) at pH 6.5. A time of forty minutes was found sufficient to achieve the equilibrium. The ANN model was designed to predict sorption efficiency of SMOS for target metal ion by combining back propagation (BP) with principle component analysis. A sigmoid axon was used as transfer function for input and output layers. The Levenberg–Marquardt Algorithm (LMA) was applied, giving a minimum mean squared error (MSE) for training and cross validation at the ninth place of decimal.展开更多
The present study is aimed to examine the adsorption characteristics of Cu(II) by using the novel cellulose acetate composite and to apply it for the removal of Cu(II) from real wastewater samples. In order to achieve...The present study is aimed to examine the adsorption characteristics of Cu(II) by using the novel cellulose acetate composite and to apply it for the removal of Cu(II) from real wastewater samples. In order to achieve this objective, ethylenediamine, diethylenetriamine, triethylenetetramine and te-traethylenepentanene were used for immobilization of grafted cellulose acetate-nanoscale manganese dioxide. Cellulose was extracted from mangrove species Avicennia marina and converted to cellulose acetate then it was formed composite with nano-manganese dioxide via precipitation of nano-manganese dioxide on it. The composite was grafted with acrylamide monomer before immobilization. The synthesized compounds were used for adsorption of Cu(II) and characterized by FT-IR, TGA and SEM. The adsorption characteristics of synthesized sorbents were optimized. Langmuir and Freundlich models were used to establish sorption equilibria. The analytical applications of these modified materials were applied successfully for the removal of Cu(II).展开更多
A supramolecular complex of Cd（II） with 1D water tapes as pillars[Cd2（dpa）2（phen）2（H2O）2]·6H2O 1 （H2dpa = diphenic acid, phen = phenanthroline）, has been synthesized and characterized by elemental analy...A supramolecular complex of Cd（II） with 1D water tapes as pillars[Cd2（dpa）2（phen）2（H2O）2]·6H2O 1 （H2dpa = diphenic acid, phen = phenanthroline）, has been synthesized and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction analysis. The crystal is of triclinic, space group P1^- with a = 9.7029（4）, b = 11.9601（5）, c = 12.1788（4） A, α = 71.6990（10）, β = 71.8740（10）, γ = 74.4680（10）°, V = 1252.39（8） A^3, C52H48Cd2N4O16, Mr = 1209.76, Z= 1, Dc = 1.604 g/cm^3,μ = 0.925 mm^-1, F（000） = 612, R = 0.0679 and wR = 0.2514 for 3870 observed reflections （I 〉 2σ（I））. Two intramolecular Cd（II） centers of this complex are encircled by two dpa^2- ligands forming an 18-membered ring, which is further assembled into a pillared three-dimensional （3D） supramolecular architecture through the synergetic effect of intermolecular face-to-face π…π stacking and weak O-H…O hydrogen-bonding interactions. Moreover, this complex exhibits photoluminescence with the main emission bands located at about 456 nm upon excitation at 355 nm in the solid state at room temperature.展开更多
Chemical compositions of natural zeolites, porcelanite (opal-CT) and local sands were determined by X-ray fluorescence (XRF) and correlated with their Pb(II) removal efficiencies. Zeolites and porcelanite were from th...Chemical compositions of natural zeolites, porcelanite (opal-CT) and local sands were determined by X-ray fluorescence (XRF) and correlated with their Pb(II) removal efficiencies. Zeolites and porcelanite were from the Mikawer, Aritain and Hannon areas in Jordan. Sands (white, red and yellow) were from the United Arab Emirates (UAE). The effect of Pb(II) concentration and zeolite dosage on removal efficiency was investigated at 25.0°C using the batch equilibrium method. Commercial kaolinite, silica and alumina were also studied for comparison. Removal efficiencies, in mg Pb(II)/g adsorbent, were: 76.9, 52.7 and 42.1 for Hannon, Mikawer and Aritain zeolites, respectively;58.2 for porcelanite;29.7, 11.0 and 8.5 for yellow, red and white sand, respectively;7.2, 3.3 and 1.3 for kaolinite, silica and alumina, respectively. XRF data indicate that adsorbents with intermediate molar ratios of Si/Al, in the range 2.70 - 2.93, are most efficient in Pb(II) removal. Scanning electron microscope (SEM) images of adsorbents suggest that morphology, in addition to chemical composition, plays a key role. In particular, a combination of factors, including shapes and sizes of crystals, channels in zeolites and pores in porcelanite, appear to favor removal of Pb(II).展开更多
Angiotensin II (Ang II) is known to elicit cardiac fibrosis by activating the AT1 receptor and CD44 expression in the in vivo model. However, the cellular/molecular mechanisms underlying cardiac fibrosis are still not...Angiotensin II (Ang II) is known to elicit cardiac fibrosis by activating the AT1 receptor and CD44 expression in the in vivo model. However, the cellular/molecular mechanisms underlying cardiac fibrosis are still not well understood. This study examines the roles of the AT1 receptor and CD44 gene expression in collagen synthesis through Ang II stimulated cardiac fibroblasts. Fibroblasts were isolated from the neonatal rat hearts;the activation of fibroblasts was evaluated using the assays of cell viability and migration, and silencing of CD44 gene expression was conducted with small interfering RNA (siRNA). Results showed that Ang II significantly increases the cell proliferation and migration in a dose-dependent manner. Upon activation, the protein levels of TGF-β1, Smad2, Smad4 and collagen I were significantly increased (all p < 0.05 vs. unstimulated cells), but these changes were significantly downregulated by the AT1 receptor blocker, telmisartan (all p < 0.05 vs. Ang II activated cells). Furthermore, mRNA and protein level of CD44 were upregulated, and there was a linear correlation between CD44 and TGF-β1 as demonstrated by Pearson correlation analysis (r = 0.955, p < 0.01). Gene transfection of fibroblasts with Ad-CD44 siRNA, as evidenced by low levels of CD44 mRNA and protein, significantly reduced the production of collagen I. In summary, these results indicate that the proliferation, migration and collagen production from Ang II activated cardiac fibroblasts are potentially mediated by the AT1 receptor and CD44. Such a signaling mechanism could be crucial for the production of collagen and the development of tissue fibrosis in the heart.展开更多
文摘A new nanometer material, nanometer AlO（OH） loaded on the fiberglass with activated carbon fibers felt（ACF） as the carrier, was prepared by hydrolytic reaction for the removal of Cd（II） from aqueous solution using column adsorption experiment. As was confirmed by XRD determination, the hydrolysis production loaded on fiberglass was similar to the orthorhombic phase AlO（OH）. SEM images showed that AlO（OH） particles were in the form of small aggregated clusters. The Thomas model was applied for estimating the kinetic parameters and the saturated adsorption ability of Cd（II） adsorption on the new adsorbent. The results showed that the maximum adsorption capacity of Cd（II） was 128.50 mg·g^-1 and 117.86 mg·g^-1 for the adsorbent mass of 0.3289 g and the adsorbent mass of 0.2867 g, respectively. The elution experiment result indicated that the adsorbed Cd ions was easily desorbed from the material with 0.1 mol·L^-1 HCl solution. Adsorption-desorption cycles showed the feasibility of repealed uses of the composited material. The adsorption capacities were influenced by pH and the initial Cd（II） concentration. The amount adsorbed was greatest at pH 6.5 and the initial Cd（II） concentration of 0.07 mg·L^-1, respectively. Nanometer AlO（OH） played a major role in the adsorption process, whereas the fiberglass and ACF were assistants in the process of removing Cd（II）. In addition, the adsorption capacities for Cd（II） were obviously reduced from 128.50 mg·L^-1 to 64.28 mg·L^-1 when Pb ions were present because Pb ions took up more adsorption sites.
文摘A facile one-step co-precipitation method was demonstrated to fabricate amorphous sulfurcontaining calcium phosphate （SCP） nanoparticles, in which the sulfur group was in-situ introduced into calcium phosphate. The resulting SCP exhibited a noticeable enhanced performance for Pb（II） removal in comparison with hydroxyapatite （HAP）, being capable of easily reducing 20 ppm of Pb（II） to below the acceptable standard for drinking water within less than 10 min. Remarkably, the saturated removal capacities of Pb（II） on SCP were as high as 1720.57 mg/g calculated by the Langmuir isotherm model, exceeding largely that of the previously reported absorbents. Significantly, SCP displayed highly selective removal ability toward Pb（II） ions in the presence of the competing metal ions （Ni（II）, Co（II）, Zn（II）, and Cd（II））. Further investigations indicated that such ultra-high removal efficiency and preferable affinity of Pb（II） ions on SCP may be reasonably ascribed to the formation of rodlike hydroxypyromorphite crystals on the surface of SCP via dissolution-precipitation and ion exchange reactions, accompanied by the presence of lead sulfide precipitates. High removal efficiency, fast removal kinetics and excellent selectivity toward Pb（II） made the obtained SCP material an ideal candidate for Pb（II） ions decontamination in practical application.
文摘A process of treatment for containing Cd 2+ wastewater by sulfate reducing bacteria with upflow anaerobic fluidized bed reactor has been studied. When the concentration of COD and Cd 2+ in the influent were 270 5mg/L and 100mg/L respectively and hydraulic retention time was 4 hours, the removal rate of COD and Cd 2+ were higher than 73 8% and 99 8% respectively. The reactor can treat as high as 1000mg/L of concentration of Cd 2+ . The highest removal velocity rate of Cd 2+ reached 2999 1mg/(L·d). And the possible relationship between sulfate reducing bacteria and methanogenic bacteria was discussed.
文摘Sawdust (SD) a very low cost material has been utilized as adsorbent material for the removal of Cd (II) from aqueous solutions after treatment with mono methylol urea (MMU) in the presence of zinc chloride as a catalyst to form MMU-SD. The reaction of MMU-SD was carried out under different conditions including MMU/SD molar ratio, catalyst concentration, and reaction time and temperature. Adsorption studies have been carried out to determine the effect of agitation time, pH, adsorbent and adsorbate concentrations on the adsorption capacity of Cd (II) ions onto MMU-SD. Langmuir, Freundlich and Redlich-Peterson isotherm models were applied in the adsorption studies. The experimental data were analyzed using various sorption kinetic models. The removal processes of Cd (II) onto MMU-SD particles could be well described by the pseudo-second order model. The maximum adsorption capacity of Cd(II) onto MMU-SD was 909 mg/g. Similarly, the Freundlich constant 1/n value was 0.45.
基金Supported by the NSRF of Hubei Provincial Education Office of China(Q20141201)the SRASF of Yichang of Hubei Province(A13-302a-02)
文摘A new 3D Cd(II) coordination polymer, [Cd(Hpidc)]n(1, H3 pidc = 2-(pyrid-2-yl)-1H-imidazole-4,5-dicarboxy acid), has been prepared and characterized by elemental analysis, IR spectra, PXRD, and single-crystal X-ray diffraction. Compound 1 crystallizes in orthorhombic, space group Fdd2 with a = 22.833(9), b = 25.536(9), c = 7.437(3) A, V = 4336(3) A3, Z = 16, Dc = 2.105 Mg·m-3, μ = 2.025 mm-1, F(000) = 2656, and the final R = 0.0261 and w R = 0.0636. The structure determination reveals that 1 exhibits a rare 3D 3-connected lig net with a point symbol of(82·10). In addition, the solid state properties such as thermogravimetric analysis and luminescence of 1 were also studied.
文摘This work examined the removal of Pb(II) using a chitosan derivative (SB, synthesized from benzaldehyde) assisted by a magnetic field. The adsorption capacity for Pb(II) was investigated. It was found that 1) the pH and concentration of the ion solution, as well as exposure time and strength of magnetic field, affected the degree of adsorption;and 2) studies of the adsorption isotherms and kinetics of ions onto SB revealed that SB showed enhanced adsorption capacity towards Pb(II) ions in a magnetic field compared with magnetically untreated samples. The Langmuir and Freundlich isotherm were applied to describe the experimental adsorption, and the maximum adsorption capacity of SB for Pb(II) was 2.5040 mg/g, when assisted by a magnetic field of 480 kA/m.
文摘Natural freshwater surface coatings(biofilms and associated minerals), which were developed in the Nanhu Lake, Changchun, P. R. China, were used as an efficient biosorbent for the removal of Cd(Ⅱ) from aqueous solutions. The batch experiments were carried out to determine the adsorption properties of Cd(Ⅱ) onto the natural surface coatings. The classical Langmuir adsorption isotherm was applied to estimating the equilibrium coefficients of Cd(Ⅱ) adsorbed on the surface coatings. The results show that the maximum adsorption capacity of the surface coatings is 434.78 μmol Cd/m2(being equal to 0.17 mmol Cd/g of surface coatings or 10.38 mmol Cd/g Fe) and the Cd(Ⅱ) removal from solution media by the natural surface coatings was shown to be strongly affected by solution pH and ion strength. The resulted information also indicates that the maximum Cd removal efficiency(CRE) was determined to be approximately 90% at initial Cd mass concentration of 0.1 mg/L(the concentration limit of Cd (Ⅱ) in wastewaters for discharge in aquatic media in Chinese legislation), and the kinetic adsorption of Cd(Ⅱ) onto the surface coatings is fast with around 70% of the total adsorption-taking place in 150 min in solution under the controlled laboratory conditions (mineral salts solution with defined speciation, ionic strength 0.05 mol/L, and 25 ℃). With the advantage of high Cd adsorption capacity, the natural surface coatings appear to be a potentially effective biosorbent for the removal and recovery of Cd (Ⅱ) from polluted water.
文摘A single-layer Artificial Neural Network (ANN) model was developed to predict the removal efficiency of Ni(II) ions from aqueous solution using shelled Moringa Oleifera seed (SMOS) powder. Batch experiments resulted into standardization of optimum conditions: biomass dosage (4.0 g), Ni(II) concentration (25 mg/L) volume (200 mL) at pH 6.5. A time of forty minutes was found sufficient to achieve the equilibrium. The ANN model was designed to predict sorption efficiency of SMOS for target metal ion by combining back propagation (BP) with principle component analysis. A sigmoid axon was used as transfer function for input and output layers. The Levenberg–Marquardt Algorithm (LMA) was applied, giving a minimum mean squared error (MSE) for training and cross validation at the ninth place of decimal.
文摘The present study is aimed to examine the adsorption characteristics of Cu(II) by using the novel cellulose acetate composite and to apply it for the removal of Cu(II) from real wastewater samples. In order to achieve this objective, ethylenediamine, diethylenetriamine, triethylenetetramine and te-traethylenepentanene were used for immobilization of grafted cellulose acetate-nanoscale manganese dioxide. Cellulose was extracted from mangrove species Avicennia marina and converted to cellulose acetate then it was formed composite with nano-manganese dioxide via precipitation of nano-manganese dioxide on it. The composite was grafted with acrylamide monomer before immobilization. The synthesized compounds were used for adsorption of Cu(II) and characterized by FT-IR, TGA and SEM. The adsorption characteristics of synthesized sorbents were optimized. Langmuir and Freundlich models were used to establish sorption equilibria. The analytical applications of these modified materials were applied successfully for the removal of Cu(II).
基金the State Key Basic Research and Development Plan of China (001CB108906)the Knowledge Innovation Program of the Chinese Academy of Sciences, the NSF (2006J0015)the Major Special Foundation of Fujian Province (2005HZ1027, 2005HZ01-1)
文摘A supramolecular complex of Cd（II） with 1D water tapes as pillars[Cd2（dpa）2（phen）2（H2O）2]·6H2O 1 （H2dpa = diphenic acid, phen = phenanthroline）, has been synthesized and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction analysis. The crystal is of triclinic, space group P1^- with a = 9.7029（4）, b = 11.9601（5）, c = 12.1788（4） A, α = 71.6990（10）, β = 71.8740（10）, γ = 74.4680（10）°, V = 1252.39（8） A^3, C52H48Cd2N4O16, Mr = 1209.76, Z= 1, Dc = 1.604 g/cm^3,μ = 0.925 mm^-1, F（000） = 612, R = 0.0679 and wR = 0.2514 for 3870 observed reflections （I 〉 2σ（I））. Two intramolecular Cd（II） centers of this complex are encircled by two dpa^2- ligands forming an 18-membered ring, which is further assembled into a pillared three-dimensional （3D） supramolecular architecture through the synergetic effect of intermolecular face-to-face π…π stacking and weak O-H…O hydrogen-bonding interactions. Moreover, this complex exhibits photoluminescence with the main emission bands located at about 456 nm upon excitation at 355 nm in the solid state at room temperature.
文摘Chemical compositions of natural zeolites, porcelanite (opal-CT) and local sands were determined by X-ray fluorescence (XRF) and correlated with their Pb(II) removal efficiencies. Zeolites and porcelanite were from the Mikawer, Aritain and Hannon areas in Jordan. Sands (white, red and yellow) were from the United Arab Emirates (UAE). The effect of Pb(II) concentration and zeolite dosage on removal efficiency was investigated at 25.0°C using the batch equilibrium method. Commercial kaolinite, silica and alumina were also studied for comparison. Removal efficiencies, in mg Pb(II)/g adsorbent, were: 76.9, 52.7 and 42.1 for Hannon, Mikawer and Aritain zeolites, respectively;58.2 for porcelanite;29.7, 11.0 and 8.5 for yellow, red and white sand, respectively;7.2, 3.3 and 1.3 for kaolinite, silica and alumina, respectively. XRF data indicate that adsorbents with intermediate molar ratios of Si/Al, in the range 2.70 - 2.93, are most efficient in Pb(II) removal. Scanning electron microscope (SEM) images of adsorbents suggest that morphology, in addition to chemical composition, plays a key role. In particular, a combination of factors, including shapes and sizes of crystals, channels in zeolites and pores in porcelanite, appear to favor removal of Pb(II).
文摘Angiotensin II (Ang II) is known to elicit cardiac fibrosis by activating the AT1 receptor and CD44 expression in the in vivo model. However, the cellular/molecular mechanisms underlying cardiac fibrosis are still not well understood. This study examines the roles of the AT1 receptor and CD44 gene expression in collagen synthesis through Ang II stimulated cardiac fibroblasts. Fibroblasts were isolated from the neonatal rat hearts;the activation of fibroblasts was evaluated using the assays of cell viability and migration, and silencing of CD44 gene expression was conducted with small interfering RNA (siRNA). Results showed that Ang II significantly increases the cell proliferation and migration in a dose-dependent manner. Upon activation, the protein levels of TGF-β1, Smad2, Smad4 and collagen I were significantly increased (all p < 0.05 vs. unstimulated cells), but these changes were significantly downregulated by the AT1 receptor blocker, telmisartan (all p < 0.05 vs. Ang II activated cells). Furthermore, mRNA and protein level of CD44 were upregulated, and there was a linear correlation between CD44 and TGF-β1 as demonstrated by Pearson correlation analysis (r = 0.955, p < 0.01). Gene transfection of fibroblasts with Ad-CD44 siRNA, as evidenced by low levels of CD44 mRNA and protein, significantly reduced the production of collagen I. In summary, these results indicate that the proliferation, migration and collagen production from Ang II activated cardiac fibroblasts are potentially mediated by the AT1 receptor and CD44. Such a signaling mechanism could be crucial for the production of collagen and the development of tissue fibrosis in the heart.
