Adsorption of diehtyl dithiophosphate on chalcopyrite has been studied using UV-visible spectroscopy at pH values of 4, 6, and 9. It was found that the adsorption of diethyl dithiophosphate decreased with the increasi...Adsorption of diehtyl dithiophosphate on chalcopyrite has been studied using UV-visible spectroscopy at pH values of 4, 6, and 9. It was found that the adsorption of diethyl dithiophosphate decreased with the increasing pH treatments. The inhibition of diethyl dithiophosphate adsorption was found prominent in higher pH as a result of metal hydroxide species formation onto chalcopyrite surface. First order kinetic has been proposed and represented the adsorption mechanism. Flotation test using Hallimond tube has also been conducted and the results were consistent with the proposed mechanism. Furthermore, the morphological changes of the treated chalcopyrite were observed using Atomic Force Microscopy (AFM) showing the propensity of growth of islands, the new surfaces as products of the reaction. The hydrophobicity was measured in the form of force of adhesion. The results resembled with the approached mechanism.展开更多
One-dimensional strontium hydroxyapatite (Sr-HAp) nanorods were successfully synthesized by a simple solvothermal method. The products were characterized via X-ray diffraction (XRD), Fourier transform infrared (....One-dimensional strontium hydroxyapatite (Sr-HAp) nanorods were successfully synthesized by a simple solvothermal method. The products were characterized via X-ray diffraction (XRD), Fourier transform infrared (.FT-IR), .cold field emission.sc.anning.elec.tron microscopy_.(FESEM), transmission.electron microscopy (TEM),photoluminescence (PL) excitation and emission spectra. The experimental results indicated that oleic acid as a surfactant played a key role in confining the growth of the Sr-HAp powders. A possible formation mechanism of the one-dimensional nanorod was proposed and elaborated. Moreover, the as-obtained Sr-HAp samoles showed an intense and bright emission band centered at 460 nm under long-wavelength UV light excitation and the contents of NaOH used in the synthetic process had an obvious impact on the optical performance of Sr-HAp powders. The possible luminescent mechanism of the Sr-HAp samples was discussed.展开更多
Alkali metal(Li, Na, K) doped ZnO powders were synthesized by solid-state reaction at different calcination temperatures and holding time. Effects of holding time and K sources on the infrared emissivity of ZnO were i...Alkali metal(Li, Na, K) doped ZnO powders were synthesized by solid-state reaction at different calcination temperatures and holding time. Effects of holding time and K sources on the infrared emissivity of ZnO were investigated. The structure and surface morphologies of samples were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The UV-Vis absorption and infrared emissivities were investigated by a UV-Vis spectrophotometer and an infrared emissometer, respectively. XRD patterns confirm the wurtzite structure of the as prepared samples with single phase. Smooth grain surfaces are detected in all doped ZnO samples, while ZnO:Li and ZnO:Na present the aggregation of grains. The redshifts in the optical band-gap are observed in K-, Na-, and Li-doped ZnO with the values 3.150, 3.144, and 3.142 eV. Due to better crystalline quality, ZnO:K shows a lower emissivity than others. The emissivity of K-doped ZnO decreases to the minimum value(0.804), at 1200 °C and holding 2 h. Compared with KNO3 as K source, K2CO3 doped ZnO has lower emissivities.展开更多
Purpose: to evaluate the in vitro influence of Copaiferalangsdorffii essential oil on the antinecrotic activity in macrophages, and on the antiapoptotic activity in macrophages and lymphocytes of Swiss mice. Methods...Purpose: to evaluate the in vitro influence of Copaiferalangsdorffii essential oil on the antinecrotic activity in macrophages, and on the antiapoptotic activity in macrophages and lymphocytes of Swiss mice. Methods: lymphocytes and macrophages were obtained from ten 60-day-old male mice weighing 42-45 g, and then cultured in 24-well plates. Cells were treated with concentrations of 2%, 5%, 10% and 20% of oil from Copaiferalangsdorffii before or after induction of apoptosis with ultraviolet light. We used positive and negative controls. Hoechst staining was performed, and then images of cells under fluorescence microscope were captured and digitalized. We used Image J_1.46o to quantify the fluorescence intensity/brightness of condensation of the chromatin ofapoptotic cells. We used one-way ANOVA with Bonferroni's and Tukey's multiple comparison tests. Results are expressed as the means of relative densities after adjustment and 95% confidence intervals; P 〈 0.05 was considered statistically significant. Results: oil from Copaiferalangsdorffii at different concentrations has decreased necrosis and apoptosis of both lymphocytes and macrophages from mice, when compared to C+ (all P 〈 0.05). Discussion: Copaiferalangsdorffii is typically Brazilian and found in the Amazon region, with anti-inflammatory, antioxidant and antineoplastic effects due to its oil compounds, such as xyloglucans and kaurenoic acid. Its potential therapeutical usage was demonstrated in a national study. The present study showed that its oil has significant in vitro antiapoptotic and antinecrotic activity and it should be tested experimentally in vivo.展开更多
Silver nanoparticles were obtained by reduction method. Various techniques, such as UV-Vis spectroscopy, transmission electron microscopy (TEM) and light-scattering spectroscopy, were used to characterize nanopartic...Silver nanoparticles were obtained by reduction method. Various techniques, such as UV-Vis spectroscopy, transmission electron microscopy (TEM) and light-scattering spectroscopy, were used to characterize nanoparticles. Sodium borohydride or sodium citrate was adopted as reduction regent, and polyvinyl alcohol or polyethylene glycol was adopted as stabilizing regent. An experimental condition was studied in detail. After the water was eliminated, the silver nanoparticle was fixed in the solid polymer. The silver nanoparticle in polymer could be re-dissolved in water. It was found that light scattering characteristic of silver nanoparticle storied in polymer was not changed. A new method of storing silver nanoparticles in solid polymer was given in this paper.展开更多
Dengue vector is responsible for millions of deaths every year and has caused disastrous impacts on health systems. The continuous use of chemical insecticides, such as carbamates, pyrethroids and organophosphates gen...Dengue vector is responsible for millions of deaths every year and has caused disastrous impacts on health systems. The continuous use of chemical insecticides, such as carbamates, pyrethroids and organophosphates generates resistant populations of the mosquito, therefore, new control methods must be investigated. The joint action of the population and guidelines for preventing the reproduction of the mosquito associated with the use of photoactivatable insecticides can be the alternative for the control of epidemiological outbreaks in affected regions. In this study, the photo-larvicidal activity of Photogem^(PG), a derivative of hematoporphyrin, was investigated against 2nd-early 3rd instar of Aedes aegypti larvae (Diptera: Culicidae) under different lighting conditions (artificial lighting system and sunlight). The dynamics of PG accumulation was characterized by CLSM (confocal laser scanning microscopy) and total time PG eliminationin solution was investigated by ultraviolet-visible spectrophotometry. The maximum photo-activity of PG was observed in 0.5 h under sunlight exposure which achieved 100% larval mortality. Fluorescence images showed a uniform distribution of PG along the digestive tract. PG remained stable in the sunlight for 48 h and in an artificial lighting system for longer periods, therefore, it can be used for the control ofAedes aegypti larvae as a new alternative to chemical insecticides. The method is considered environmentally friendly due to its rapid degradation in the presence of light. Further studies are required, so that the potential of the technique can be explored in real breeding places.展开更多
The nucleation and growth mechanism and polymorph-property correlations in the molecular cocrystal field are widely sought but currently remain unclear. Herein, a new wire-like morphology of phenazine(Phz)-chloranilic...The nucleation and growth mechanism and polymorph-property correlations in the molecular cocrystal field are widely sought but currently remain unclear. Herein, a new wire-like morphology of phenazine(Phz)-chloranilic acid(H2ca) cocrystal(PHC) is demonstrated for the first time, and the self-assembly of Phz and H2ca is controlled to selectively prepare kinetically stable wires and thermodynamically stable plates. Specifically, low precursor concentration is beneficial for one-dimensional(1D) self-assembly along the [010] crystallographic direction, while only supersaturation can trigger 2D self-assembly along the [100] and [010] directions, respectively. This is understandable in terms of the(020) face showing the largest attachment energy(Eatt) and the(002) face possessing the smallest surface energy(Esurf). Moreover, anisotropic Raman spectra related to the mode symmetry and atomic displacements in two types of PHCs are revealed, and the same Raman-active vibrational bands of PHC wire and plate show different polarization responses, which is intrinsically ascribed to their different molecular orientations.Overall, this is the first case that morphologies of cocrystal are precisely tuned with comprehensive investigations of their anisotropic vibrational characteristics.展开更多
Gallium oxide (Ga203) films were deposited on singlecrystalline sapphire (0001) substrate by radio frequency (RF) magnetron sputtering technique in the temperature range of 300--500 ℃. The microstructure of the...Gallium oxide (Ga203) films were deposited on singlecrystalline sapphire (0001) substrate by radio frequency (RF) magnetron sputtering technique in the temperature range of 300--500 ℃. The microstructure of the fl-Ga203 films were investigated in detail using X-ray diffractometer (XRD) and scanning electron microscope (SEM). The results show that the film prepared at 500℃ exhibits the best crystallinity with a monoclinic structure (fl-Ga203). Structure analysis reveals a clear out-of-plane orientation offl-Ga203 (201) II A1203 (0001). The average transmittance of these films in the visible wavelength range exceeds 90%, and the optical band gap of the films varies from 4.68 eV to 4.94 eV which were measured by an ultraviolet-visible-near infrared (UV-vis-NIR) spectrophotometer. Therefore, it is hopeful that the fl-Ga203 film can be used in the UV optoelectronic devices.展开更多
文摘Adsorption of diehtyl dithiophosphate on chalcopyrite has been studied using UV-visible spectroscopy at pH values of 4, 6, and 9. It was found that the adsorption of diethyl dithiophosphate decreased with the increasing pH treatments. The inhibition of diethyl dithiophosphate adsorption was found prominent in higher pH as a result of metal hydroxide species formation onto chalcopyrite surface. First order kinetic has been proposed and represented the adsorption mechanism. Flotation test using Hallimond tube has also been conducted and the results were consistent with the proposed mechanism. Furthermore, the morphological changes of the treated chalcopyrite were observed using Atomic Force Microscopy (AFM) showing the propensity of growth of islands, the new surfaces as products of the reaction. The hydrophobicity was measured in the form of force of adhesion. The results resembled with the approached mechanism.
基金Supported by the National Natural Science Foundation of China (20876157)the Fundamental Research Funds for the Central Universities (FRF-BR-10-002A)
文摘One-dimensional strontium hydroxyapatite (Sr-HAp) nanorods were successfully synthesized by a simple solvothermal method. The products were characterized via X-ray diffraction (XRD), Fourier transform infrared (.FT-IR), .cold field emission.sc.anning.elec.tron microscopy_.(FESEM), transmission.electron microscopy (TEM),photoluminescence (PL) excitation and emission spectra. The experimental results indicated that oleic acid as a surfactant played a key role in confining the growth of the Sr-HAp powders. A possible formation mechanism of the one-dimensional nanorod was proposed and elaborated. Moreover, the as-obtained Sr-HAp samoles showed an intense and bright emission band centered at 460 nm under long-wavelength UV light excitation and the contents of NaOH used in the synthetic process had an obvious impact on the optical performance of Sr-HAp powders. The possible luminescent mechanism of the Sr-HAp samples was discussed.
基金Project(JB141405)supported by the Fundamental Research Funds for the Central Universities of China
文摘Alkali metal(Li, Na, K) doped ZnO powders were synthesized by solid-state reaction at different calcination temperatures and holding time. Effects of holding time and K sources on the infrared emissivity of ZnO were investigated. The structure and surface morphologies of samples were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The UV-Vis absorption and infrared emissivities were investigated by a UV-Vis spectrophotometer and an infrared emissometer, respectively. XRD patterns confirm the wurtzite structure of the as prepared samples with single phase. Smooth grain surfaces are detected in all doped ZnO samples, while ZnO:Li and ZnO:Na present the aggregation of grains. The redshifts in the optical band-gap are observed in K-, Na-, and Li-doped ZnO with the values 3.150, 3.144, and 3.142 eV. Due to better crystalline quality, ZnO:K shows a lower emissivity than others. The emissivity of K-doped ZnO decreases to the minimum value(0.804), at 1200 °C and holding 2 h. Compared with KNO3 as K source, K2CO3 doped ZnO has lower emissivities.
文摘Purpose: to evaluate the in vitro influence of Copaiferalangsdorffii essential oil on the antinecrotic activity in macrophages, and on the antiapoptotic activity in macrophages and lymphocytes of Swiss mice. Methods: lymphocytes and macrophages were obtained from ten 60-day-old male mice weighing 42-45 g, and then cultured in 24-well plates. Cells were treated with concentrations of 2%, 5%, 10% and 20% of oil from Copaiferalangsdorffii before or after induction of apoptosis with ultraviolet light. We used positive and negative controls. Hoechst staining was performed, and then images of cells under fluorescence microscope were captured and digitalized. We used Image J_1.46o to quantify the fluorescence intensity/brightness of condensation of the chromatin ofapoptotic cells. We used one-way ANOVA with Bonferroni's and Tukey's multiple comparison tests. Results are expressed as the means of relative densities after adjustment and 95% confidence intervals; P 〈 0.05 was considered statistically significant. Results: oil from Copaiferalangsdorffii at different concentrations has decreased necrosis and apoptosis of both lymphocytes and macrophages from mice, when compared to C+ (all P 〈 0.05). Discussion: Copaiferalangsdorffii is typically Brazilian and found in the Amazon region, with anti-inflammatory, antioxidant and antineoplastic effects due to its oil compounds, such as xyloglucans and kaurenoic acid. Its potential therapeutical usage was demonstrated in a national study. The present study showed that its oil has significant in vitro antiapoptotic and antinecrotic activity and it should be tested experimentally in vivo.
文摘Silver nanoparticles were obtained by reduction method. Various techniques, such as UV-Vis spectroscopy, transmission electron microscopy (TEM) and light-scattering spectroscopy, were used to characterize nanoparticles. Sodium borohydride or sodium citrate was adopted as reduction regent, and polyvinyl alcohol or polyethylene glycol was adopted as stabilizing regent. An experimental condition was studied in detail. After the water was eliminated, the silver nanoparticle was fixed in the solid polymer. The silver nanoparticle in polymer could be re-dissolved in water. It was found that light scattering characteristic of silver nanoparticle storied in polymer was not changed. A new method of storing silver nanoparticles in solid polymer was given in this paper.
文摘Dengue vector is responsible for millions of deaths every year and has caused disastrous impacts on health systems. The continuous use of chemical insecticides, such as carbamates, pyrethroids and organophosphates generates resistant populations of the mosquito, therefore, new control methods must be investigated. The joint action of the population and guidelines for preventing the reproduction of the mosquito associated with the use of photoactivatable insecticides can be the alternative for the control of epidemiological outbreaks in affected regions. In this study, the photo-larvicidal activity of Photogem^(PG), a derivative of hematoporphyrin, was investigated against 2nd-early 3rd instar of Aedes aegypti larvae (Diptera: Culicidae) under different lighting conditions (artificial lighting system and sunlight). The dynamics of PG accumulation was characterized by CLSM (confocal laser scanning microscopy) and total time PG eliminationin solution was investigated by ultraviolet-visible spectrophotometry. The maximum photo-activity of PG was observed in 0.5 h under sunlight exposure which achieved 100% larval mortality. Fluorescence images showed a uniform distribution of PG along the digestive tract. PG remained stable in the sunlight for 48 h and in an artificial lighting system for longer periods, therefore, it can be used for the control ofAedes aegypti larvae as a new alternative to chemical insecticides. The method is considered environmentally friendly due to its rapid degradation in the presence of light. Further studies are required, so that the potential of the technique can be explored in real breeding places.
基金supported by the National Natural Science Foundation of China (51303185, 21021091, 51033006, 51222306, 51003107, 61201105, 3591027043, 91222203, 91233205, 21473222 and 21773040)the Ministry of Science and Technology of China (2011CB808400, 2011CB932300, 2013CB933403, 2013CB933500 and 2014CB643600)the Chinese Academy of Sciences (Y42D0A12D1 and Y42D0412D1)。
文摘The nucleation and growth mechanism and polymorph-property correlations in the molecular cocrystal field are widely sought but currently remain unclear. Herein, a new wire-like morphology of phenazine(Phz)-chloranilic acid(H2ca) cocrystal(PHC) is demonstrated for the first time, and the self-assembly of Phz and H2ca is controlled to selectively prepare kinetically stable wires and thermodynamically stable plates. Specifically, low precursor concentration is beneficial for one-dimensional(1D) self-assembly along the [010] crystallographic direction, while only supersaturation can trigger 2D self-assembly along the [100] and [010] directions, respectively. This is understandable in terms of the(020) face showing the largest attachment energy(Eatt) and the(002) face possessing the smallest surface energy(Esurf). Moreover, anisotropic Raman spectra related to the mode symmetry and atomic displacements in two types of PHCs are revealed, and the same Raman-active vibrational bands of PHC wire and plate show different polarization responses, which is intrinsically ascribed to their different molecular orientations.Overall, this is the first case that morphologies of cocrystal are precisely tuned with comprehensive investigations of their anisotropic vibrational characteristics.
基金supported by the National Natural Science Foundation of China(Nos.61274113,61404091,61505144,51502203 and 51502204)the Opening Fund of Key Laboratory of Silicon Device Technology in Chinese Academy of Sciencesthe Tianjin Natural Science Foundation(Nos.14JCZDJC31500 and 14JCQNJC00800)
文摘Gallium oxide (Ga203) films were deposited on singlecrystalline sapphire (0001) substrate by radio frequency (RF) magnetron sputtering technique in the temperature range of 300--500 ℃. The microstructure of the fl-Ga203 films were investigated in detail using X-ray diffractometer (XRD) and scanning electron microscope (SEM). The results show that the film prepared at 500℃ exhibits the best crystallinity with a monoclinic structure (fl-Ga203). Structure analysis reveals a clear out-of-plane orientation offl-Ga203 (201) II A1203 (0001). The average transmittance of these films in the visible wavelength range exceeds 90%, and the optical band gap of the films varies from 4.68 eV to 4.94 eV which were measured by an ultraviolet-visible-near infrared (UV-vis-NIR) spectrophotometer. Therefore, it is hopeful that the fl-Ga203 film can be used in the UV optoelectronic devices.