The lime-depressed pyrite from Cu differential flotation tailings with acid mine drainage(AMD)as a natural activator was recovered.The effect of AMD on lime-depressed pyrite flotation was investigated by a series of l...The lime-depressed pyrite from Cu differential flotation tailings with acid mine drainage(AMD)as a natural activator was recovered.The effect of AMD on lime-depressed pyrite flotation was investigated by a series of laboratory flotation tests and surface analytical techniques.Flotation test results indicated that AMD could effectively activate the pyrite flotation with a sodium butyl xanthate(SBX)collector,and a high-quality sulfur concentrate was obtained.Pulp ion concentration analysis results indicated that AMD facilitated desorption of Ca~(2+)and adsorption of Cu~(2+)on the depressed-pyrite surface.Adsorption measurements and contact angle analysis results confirmed that adding AMD improved the adsorption amount of SBX collector on the pyrite surface and increased the contact angle by 31°.Results of Raman spectroscopy and X-ray photoelectron spectroscopy analysis indicated that AMD treatment promoted the formation of hydrophobic species(S~0 hydrophobic entity and copper sulfides)and the removal of hydrophilic calcium and iron species on the pyrite surface,which reinforced the adsorption of collector.The findings of the present research provide important theoretical basis and technical support for a cleaner production of copper sulfide ores.展开更多
Sodium 2,3-dihydroxypropyl dithiocarbonate(SGX), which contains —OH and —CSS— in the molecule, was used to explore selective depression of galena from chalcopyrite in the flotation tests with ammonium dibutyl dit...Sodium 2,3-dihydroxypropyl dithiocarbonate(SGX), which contains —OH and —CSS— in the molecule, was used to explore selective depression of galena from chalcopyrite in the flotation tests with ammonium dibutyl dithiophosphate(DDTP), and zeta potential and adsorption measurements were performed to study the interaction between SGX and minerals. The flotation tests of single minerals show that SGX has slight activation on chalcopyrite and strong depression on galena in the whole p H range. With SGX dosage increasing, the recovery of galena decreases rapidly, while that of chalcopyrite increases slightly. At p H=6, the copper grade and recovery of concentrate are 29.52% and 82.15% respectively when mixture of two minerals is tested. Zeta potential and adsorption measurements indicate that SGX has strong adsorption on galena and slight adsorption on chalcopyrite.展开更多
Chlorophyll fluorescence emission, pigment composition and photosynthetic rate of shade-grown cotton ( Gossypium hirsutum L.) plants were measured immediately after suddenly exposing to full sunlight and at regular in...Chlorophyll fluorescence emission, pigment composition and photosynthetic rate of shade-grown cotton ( Gossypium hirsutum L.) plants were measured immediately after suddenly exposing to full sunlight and at regular intervals there after within 15 d. Photoinhibition occurred in shade-grown cotton leaves immediately after exposed to full sunlight. The chlorophyll fluorescence parameter F-v/F-m and PhiPS II, which reflect the efficiency of PS II,obviously decreased in shade-grown leaves, much lower than that of the full sunlight-grown leaves. On the contrary, F-o value was sharply increased. Neither of these parameters could completely recover till next morning. The photoinhibition was chronic and continued for about 4 d, while the F-v/F-m and the net photosynthetic rate ( P-n) continued to decline, then began to increase gradually 6 d later and turned stable after 10 - 12 d, appearing as an acclimation phenomenon. However, the final value of F-v/F-m and P-n did not reach the level as in those leaves grown in the full sunlight ever before. The final P-n was higher by 60% than that before exposure, but lower for more than 40% than that of the full sunlight-grown leaves. The most notable response of chloroplast pigment composition was a pronounced increase in the pool size of carotenoids in xanthophyll cycle over a period of 3 d. The results indicated that when shade-grown cotton seedlings were suddenly transferred to the full sunlight, the decline of F-v/F-m and P-n might associate with the damage of the PS II reaction center. During the light acclimation, photoprotective mechanisms such as the xanthophyll cycle-dependent energy dissipation were increased, so that photodamage in leaves transferred from low to high light might be reduced.展开更多
Pseudo glycolythiourea acid(PGA) was synthesized and used as depressant for flotation separation of Cu and Mo.The results indicate that a low amount of PGA has strong depression effect on chalcopyrite.Mo grade of 26...Pseudo glycolythiourea acid(PGA) was synthesized and used as depressant for flotation separation of Cu and Mo.The results indicate that a low amount of PGA has strong depression effect on chalcopyrite.Mo grade of 26.17% and recovery of 89.83% were achieved with rougher and scavenger one time and cleaners twice,while the recovery of Mo was deceased by 2% when Na2S was used as depressant.Measurement on adsorption of PGA on the mineral surface indicates that PGA and xanthate were adsorbed on mineral surface by competition,and PGA was adsorbed on chalcopyrite surface much stronger than on molybdenite surface.FTIR results indicate a chemical absorption process for PGA on chalcopyrite surface and a physical adsorption process on molybdenite surface.The frontier orbital calculation shows that the S atom is an active center,and the depression of PGA can be explained with the Fermi level of energy based on the electrochemical mechanism.展开更多
[Objective] To produce drug resistance, seek non-toxic environmental so as to change the current biological drugs that did not excessive use of antibiotics. [Methods] A strain of Bacillus was purified and isolated fro...[Objective] To produce drug resistance, seek non-toxic environmental so as to change the current biological drugs that did not excessive use of antibiotics. [Methods] A strain of Bacillus was purified and isolated from fresh and healthy in- testines of grass carps. Biochemical identification was carried out by conventional bacterial biochemical test method. Two pairs of primers were designed, 16S rRNA detection and sequencing analysis were carried out. Drug sensitive test was carried out by agar diffusion method. In vitro inhibition test on Staphylococcus aureus was carried out by Oxford cup method. [Results] The isolated bacterium had basically the same biochemical characters as Bacillus subtilis; and the homology reached 100%. Thus, the isolated bacterium was identified to be Bacillus subtilis. It was insensitive to amoxicillin, ampicillin, penicillin G and so on, but sensitive to amikacin, cefalexin, ciprofloxacin and cefradine. The inhibitory effects of Bacillus subtilis on Staphylococ- cus aureus were significant. The minimum inhibitory concentration (MIC) was 2.8×10^8×2^-5/ml and minimum bactericidal concentration (MBC) was 2.8×10^8×2^-2/ml. [Conclusions] The isolated Bacillus subtilis could be used to prevent and control diseases caused by Staphylococcus aureus, and reduce the abuse of antibiotics.展开更多
A novel synthesized reagent, O,O-bis(2,3-dihydroxypropyl) dithiophosphate (DHDTP), was investigated as depressant on the depression of chalcopyrite and galena, when ammonium dibutyl dithiophosphate (DDTP) was us...A novel synthesized reagent, O,O-bis(2,3-dihydroxypropyl) dithiophosphate (DHDTP), was investigated as depressant on the depression of chalcopyrite and galena, when ammonium dibutyl dithiophosphate (DDTP) was used as the collector in flotation tests. Zeta potential and adsorption measurement were performed to study the interaction between depressant and minerals. The flotation tests of two minerals show that DHDTP has slight depression on chalcopyrite in the whole pH range and strong depression on galena in the pH range of 6-10. When DHDTP dosage is increased, the recovery of galena decreases rapidly, while that of the chalcopyrite decreases slightly. The satisfied separation results of artificially mixed samples are that the copper grade and recovery rates of concentrate are 24.08% and 81%, respectively, when the pH is 6 with 278 mg/L DHDTP. Zeta potential and adsorption measurements show that DHDTP has more strongly adsorotion capacity to galena than chalcoovrite.展开更多
In midday ginkgo ( Ginkgo biloba L.) leaves have to bear photon flux density over 1400 μmol·m -2 ·s -1 in combination with high temperatures around 35 ℃ at natural habitat. They show typical mi...In midday ginkgo ( Ginkgo biloba L.) leaves have to bear photon flux density over 1400 μmol·m -2 ·s -1 in combination with high temperatures around 35 ℃ at natural habitat. They show typical midday depression of stomatal conductance and of CO 2 assimilation rate. The zeaxanthin changes with light intensity during the day. The influence of the combination of strong light and temperature on photoinhibition was also examined in the laboratory. A low CO 2 internal conductance (31 mmol·m -2 ·s -1 ) was found in ginkgo leaves, which had been exposed to excessive light at temperature between 15 ℃ and 35 ℃ with reduced CO 2 (80 μL·L -1 ) or oxygen (2%) for 2 h, causing a low CO 2 concentration at the carboxylation site and a high proportion of photorespiration. The ratio of electron transport to CO 2 fixation was rather high in ginkgo (16 e -/CO 2 at 25 ℃) as compared with other plants. It increased with temperature also in 2% O 2 which could not be explained solely as due to change of photorespiration. The reduction of oxygen in 340 or 80 μL·L -1 CO 2 had no effect on the extent of photoinhibition at all temperatures, which indicated that electron flow caused by photorespiration in excess light was negligible in protective effect in ginkgo leaves. However, a decreased CO 2 concentration increased photoinhibition, especially at high temperature. It is concluded that the dissipation of excessive excitation energy in the PSⅡ antennae through the xanthophyll cycle may be the major protective mechanism to preventing from the deteriorated effects of strong light in ginkgo leaves.展开更多
Changes in the efficiency of the primary light energy conversion, fluorescence quenching parameters and contents of photosynthetic pigments were compared between two wheat ( Triticum aestivum L.) genotypes in respo...Changes in the efficiency of the primary light energy conversion, fluorescence quenching parameters and contents of photosynthetic pigments were compared between two wheat ( Triticum aestivum L.) genotypes in response to high light stress. The contents of chlorophyll and carotenoid in “Jing_411' were slightly higher than those in “Xiaoyan_54'. Under high light stress, photoinhibition as indicated by a sustained decrease in PSⅡ photochemical efficiency was more pronounced in “Jing_411' than in “Xiaoyan_54'. The content of ascorbate and the activity of the deepoxidase were higher in “Xiaoyan_54' than in “Jing_411'. The genotypic difference in resistance to photoinhibition is related to the capacity to dissipate the excess energy nonradiatively.展开更多
The performance of hydroxamic polyacrylamide(HPAM) in mineral flotation was tested on the samples of calcite, diaspore and pyrite. It is found that HPAM expresses intensive depression on pyrite and can be used as effe...The performance of hydroxamic polyacrylamide(HPAM) in mineral flotation was tested on the samples of calcite, diaspore and pyrite. It is found that HPAM expresses intensive depression on pyrite and can be used as effective depressants for pyrite. The depression mechanism of HPAM to pyrite was investigated by the determination of contact angle, zeta potential, adsorptive capacity for collectors and infrared spectrum. A lower contact angle, more negative zeta potential, less xanthate adsorptive capacity, and the formation of chemical bonding were determined, which reveals that the strong chemical interactions exist between HPAM and pyrite surface. The group electronegativity of HPAM was calculated to explain the differences of interaction between reagent and minerals.展开更多
AIM: To evaluate the anti-viral effect of emodin plus Astragalus polysaccharide (APS) in hepatitis B virus (HBV) transgenic mice.METHODS: Sixty HBV transgenic mice (HBV TGM) whose weight varied between 18 and 24 g wer...AIM: To evaluate the anti-viral effect of emodin plus Astragalus polysaccharide (APS) in hepatitis B virus (HBV) transgenic mice.METHODS: Sixty HBV transgenic mice (HBV TGM) whose weight varied between 18 and 24 g were randomly divided into 3 groups, with 20 mice in each group. Group A was the normal control, where the mice were treated with physiological saline; group B was the positive control where the mice were treated with lamivudine solution (100 mL/kg per day). Group C was the experimental group where the mice were treated with physiological saline containing emodin and APS (57.59 mg/kg per day and 287.95 mg/kg per day, respectively). The mice were treated daily for 3 wk. After 1 wk recovery time, the mice were sacrifi ced and serum as well as liver tissues were collected for ELISA and histological examination.RESULTS: After 21 d treatment, HBV DNA levels in group B and group C significantly declined when compared with group A (P < 0.05). However, a signif icant increase in HBV DNA content was observed in group B, whereas this phenomenon was not observed in group C. A reduction in the contents of HBsAg, HBeAg and HBcAg in the mice from group B and C was observed when compared with group A.CONCLUSION: Emodin and APS have a weak but persistent inhibitory effect on HBV replication in vivo, which may function as a supplementary modality in the treatment of hepatitis B infection.展开更多
In order to selectively separate chalcopyrite from pyrite,the effect of organic depressant lignosulfonate calcium(LSC) on the flotation separation of chalcopyrite from pyrite was investigated by flotation tests. The d...In order to selectively separate chalcopyrite from pyrite,the effect of organic depressant lignosulfonate calcium(LSC) on the flotation separation of chalcopyrite from pyrite was investigated by flotation tests. The depression mechanism was studied by Fourier-transform-infrared(FTIR) analysis. The flotation tests of single mineral show that LSC can depress the flotation of pyrite in a certain pH range,but it has little effect on chalcopyrite flotation. Flotation separation of a mixture of chalcopyrite and pyrite can be completed to obtain a copper concentrate grade up to 24.73% with a recovery of 80.36%. IR analysis shows that LSC and butyl xanthate compete in absorption on pyrite surface,and there exists an LSC characteristic peak on pyrite surface. There is little adsorption of LSC on chalcopyrite.展开更多
Chinese seabuckthorn berry contains functional components. The berry was extracted by ethanol-water solution. MTT assay and growth rate method were applied to determine antibacterial ability in vitro of the extract so...Chinese seabuckthorn berry contains functional components. The berry was extracted by ethanol-water solution. MTT assay and growth rate method were applied to determine antibacterial ability in vitro of the extract solution. The antibacterial and antifungal assay indicated that the extract exhibited different degree of inhibitory activity. The result showed that the extract at a concentration of 1 250 mg/L had the maximum inhibitory effect against Escherichia coli, Bacillus subtilis, and Staphylococcus aureus. Inhibitory effect against B. subtilis was much larger than that against the other two bacterial species. MIC values(minimum inhibitory concentration) of the extract on three bacterial species were 5 000, 1 250, and 1 000 mg/L respectively. IC_(50)(50% inhibiting concentration) evaluation of Trichoderma viride, Rhizopus stolonifer, Aspergillus niger, Penicillium expansum, and Vintage Red indicated that the berry had the strongest inhibitory effect against P. expansum(5 520 mg/L), while it had the weakest inhibitory effect against R. stolonifer(18 870 mg/L). The results proved that seabuckthorn berry had highly effective and comprehensive antimicrobial function.展开更多
AIM: To investigate the inhibitory effect and possible mechanism of action of schisandrin B in SC-B on gastric cancer cells in vitro.METHODS: SC-B consisted of schisandrin B, aloeemodin, and Astragalus polysaccharid...AIM: To investigate the inhibitory effect and possible mechanism of action of schisandrin B in SC-B on gastric cancer cells in vitro.METHODS: SC-B consisted of schisandrin B, aloeemodin, and Astragalus polysaccharides. Exponentially growing human gastric cancer SGO7901 cells were divided into six treatment groups: (1) control group (RPMI 1640 medium); (2) negative control group (2% DMSO); (3) positive control group (50 mg/L 5-Fluorouracil, 5-FU); (4) low-dose group (LSC, final concentration of schisandrin B, 25 mg/L), (5) moderate-dose group (MSC, final concentration of schisandrin B, 50 mg/L); (6) highdose group (HSC, final concentration of schisandrin B, 100 mg/L). Follow-up was done at 12-48 h. An MTT (Methylthiazolyldiphenyl-tetrazolium bromide) assay was used to examine the inhibitory effect of SOB on gastric cancer cells. The mitosis index was assessed using an inverted microscope. Flow cytometry was used to visualize the cell cycle. An RT-PCR (Reverse transcription-Polymerase chain reaction) -based assay was used to detect mRNA expression for cyclin D1 and glyceraldehyde-3-phosphate dehydrogenase (GAPDH).RESULTS: The MTT assay showed that the number of living cells in the LSC, MSC and HSC groups was significantly smaller than that in the DMSO-treated group (P 〈 0.05) at 12-48 h. The inhibitory rate (IR) of the LSC group was 41.15% ± 3.86%, 59.24% ± 5.34% and 69.93% ± 7.81% at 12, 24 and 48 h, respectively. The IR of the MSC group was 42.82% ± 4.94%, 62.68% ± 7.58% and 71.79% ± 8.12% at 12, 24 and 48 h, respectively. The IR of the HSC group was 37.50% ± 3.21%, 40.34% ± 2.98% and 61.99% ± 4.88% at 12, 24 and 48 h, respectively. These results suggested that a moderate dosage had the most obvious inhibitory efficacy at 48 h. Compared to the DMSO group, the mitosis index of the LSC, MSC, HSC groups was greatly decreased (P 〈 0.05) at all time points. Any dose of SC-B suppressed mitosis within 12-48 h. Compared to the DMSO group, the percentage of cells in the G0/G1 phase of the MSC group was greatly increased, and that of the S + G2M phase was greatly decreased, while the percentage of cell inhibition (PCI) in the MSC group was greatly increased (P 〈 0.05). This suggested that SC-B could exclusively arrest cells in the G0/G1 phase. Cyclin D1 mRNA expression was lower in the MSC group than that in the DMSO group (P 〈 0.05).CONCLUSION: SC-B can inhibit the proliferation and aberrant mitosis of human gastric cancer SCG-7901 cells /n v/tro, This inhibitory effect may be due to the down- regulation of cyclin D1 mRNA expression, which causes cell cycle arrest of gastric cancer cells.展开更多
A small molecular organic depressor glycerine-xanthate was synthesized. The effect of glycerine-xanthate on the flotation of sulfide minerals was investigated based on a function of pH value and concentration of glyce...A small molecular organic depressor glycerine-xanthate was synthesized. The effect of glycerine-xanthate on the flotation of sulfide minerals was investigated based on a function of pH value and concentration of glycerine-xanthate through flotation experiments in the presence and absence of Cu^2+. The results show that glycerinee-xanthate has a strong dressing effect on marmatite at pH〉6 and on arsenopyrite in weak acid and base conditions with butyl-xanthate as collector. In the presence of glycerine -xanthate, marmatite is activated by addition of Cu^2+, but arsenopyrite cannot be activated and remains unfloatable. So the selective separation can be achieved for two minerals. The depression of glycerine-xanthate on sulfide minerals was discussed based on the radical electronegative calculation and the theory of HSAB. Infrared spectrum shows that there are some -OH and-CSS-in glycedne-xanthate molecule, which competes with butyl-xanthate on the mineral surface. As a result of many hydrophilic groups in glycerine-xanthate, the surfaces of marmatite and arsenopyrite become hydrophilic, thus the flotation of marmatite and arsenopyrite is depressed. The collector is adsorbed preferentially on the surface of marmatite and it shows a better floatability in the presence of Cu^2+, whereas, the surface of arsenopyrite absorbs glycerine-xanthate and the flotation of arsenopyrite is depressed by glycerine-xanthate.展开更多
AIM: To explore the effect of Astraga/us mongholicus polysaccharide (APS) on gene expression and mitogenactivated protein kinase (MAPK) transcriptional activity in intestinal epithelial cells (IEC). METHODS: I...AIM: To explore the effect of Astraga/us mongholicus polysaccharide (APS) on gene expression and mitogenactivated protein kinase (MAPK) transcriptional activity in intestinal epithelial cells (IEC). METHODS: IEC were divided into control group, lipopolysaccharide (LPS) group, LPS+ 50 μg/mL APS group, LPS+ 100 μg/mL APS group, LPS+ 200 μg/mL APS group, and LPS+ 500 μg/mL APS group. Levels of mRNAs in LPS-induced inflammatory factors, tumor necrosis factor (TNF)-α and interleukin (IL)-8, were measured by reverse transcription-polymerase chain reaction. MAPK protein level was measured by Western blotting. RESULTS: The levels of TNF-α and IL-8 mRNAs were significantly higher in IEC with LPS-induced damage than in control cells. APS significantly abrogated the LPS-induced expression of the TNF-α and IL-8 genes. APS did not block the activation of extracellular signal- regulated kinase or c Jun amino-terminal kinase, but inhibited the activation of p38, suggesting that APS inhibits LPS-induced production of TNF-α and IL-8 mRNAs, possibly by suppressing the p38 signaling pathway.CONCLUSION: APS-modulated bacterial productmediated p38 signaling represents an attractive strategy for prevention and treatment of intestinal inflammation.展开更多
Tragacanth gum(TG)was explored as a depressant to realize the flotation separation of molybdenite and talc.The flotation experiments indicated that when using potassium butyl xanthate(PBX)as a collector,molybdenite sh...Tragacanth gum(TG)was explored as a depressant to realize the flotation separation of molybdenite and talc.The flotation experiments indicated that when using potassium butyl xanthate(PBX)as a collector,molybdenite showed excellent floatability while talc was completely depressed by TG,thus realizing the flotation separation of the two minerals.X-ray photoelectron spectroscopy(XPS)analysis results showed that TG was adsorbed on molybdenite surface via chemisorption.The results of contact angle measurement,Fourier transform infrared(FTIR)spectroscopy,and time-of-flight secondary ion mass spectrometry(ToF-SIMS)indicated that the pre-adsorption of TG on molybdenite could not hinder the further chemisorption of PBX on molybdenite.Because PBX has no collecting ability on talc,the flotation separation of molybdenite and talc came true using PBX to collect molybdenite and TG to depress talc.展开更多
Objective:To identify new favorable agents and develop novel approaches for the chemoprevention and treatment of superficial bladder cancer and investigate the effects of combination of retinoids and interferon α-2a ...Objective:To identify new favorable agents and develop novel approaches for the chemoprevention and treatment of superficial bladder cancer and investigate the effects of combination of retinoids and interferon α-2a on growth inhibition and apoptosis induction in bladder cancer cell lines. Methods:Four bladder cancer cell lines,grade 1 to 3,and two retinoids,all-trans-retinoic acid(ATRA),9-cis retinoic acid(9cRA),combined with interferon α-2a(INF),were used in the study.We compared the competence of these agents to inhibit growth,induce apoptosis,affect the expression of nuclear retinoid receptors,and modulate STAT1 protein. Results: Most of the bladder cancer cell lines were resistant to the effect of ATRA and 9cRA on growth inhibition and apoptosis induction,even at higher concentration(10 -5M).The effects of ATRA and 9c RA on cell growth and apoptosis were enhanced by INF α- 2a. Combination of ATRA and IFNα-2a induced RARβ and Stat 1 expression in three bladder cancer cell lines. Conclusion:The results demonstrated that INFα-2a synergize with the inhibitory effect of ATRA and 9c RA on the growth inhibition and apoptosis of bladder cancer cells in vitro,which suggested that it has a potential interest for the treatment of transitional cell carcinoma of bladder.展开更多
基金financially supported from the National Natural Science Foundation of China(No.52164021)the Natural Science Foundation of Yunnan Province,China(No.2019FB078)。
文摘The lime-depressed pyrite from Cu differential flotation tailings with acid mine drainage(AMD)as a natural activator was recovered.The effect of AMD on lime-depressed pyrite flotation was investigated by a series of laboratory flotation tests and surface analytical techniques.Flotation test results indicated that AMD could effectively activate the pyrite flotation with a sodium butyl xanthate(SBX)collector,and a high-quality sulfur concentrate was obtained.Pulp ion concentration analysis results indicated that AMD facilitated desorption of Ca~(2+)and adsorption of Cu~(2+)on the depressed-pyrite surface.Adsorption measurements and contact angle analysis results confirmed that adding AMD improved the adsorption amount of SBX collector on the pyrite surface and increased the contact angle by 31°.Results of Raman spectroscopy and X-ray photoelectron spectroscopy analysis indicated that AMD treatment promoted the formation of hydrophobic species(S~0 hydrophobic entity and copper sulfides)and the removal of hydrophilic calcium and iron species on the pyrite surface,which reinforced the adsorption of collector.The findings of the present research provide important theoretical basis and technical support for a cleaner production of copper sulfide ores.
基金Project(2012BAB01B03)supported by National Key Technologies R&D Program of China
文摘Sodium 2,3-dihydroxypropyl dithiocarbonate(SGX), which contains —OH and —CSS— in the molecule, was used to explore selective depression of galena from chalcopyrite in the flotation tests with ammonium dibutyl dithiophosphate(DDTP), and zeta potential and adsorption measurements were performed to study the interaction between SGX and minerals. The flotation tests of single minerals show that SGX has slight activation on chalcopyrite and strong depression on galena in the whole p H range. With SGX dosage increasing, the recovery of galena decreases rapidly, while that of chalcopyrite increases slightly. At p H=6, the copper grade and recovery of concentrate are 29.52% and 82.15% respectively when mixture of two minerals is tested. Zeta potential and adsorption measurements indicate that SGX has strong adsorption on galena and slight adsorption on chalcopyrite.
文摘Chlorophyll fluorescence emission, pigment composition and photosynthetic rate of shade-grown cotton ( Gossypium hirsutum L.) plants were measured immediately after suddenly exposing to full sunlight and at regular intervals there after within 15 d. Photoinhibition occurred in shade-grown cotton leaves immediately after exposed to full sunlight. The chlorophyll fluorescence parameter F-v/F-m and PhiPS II, which reflect the efficiency of PS II,obviously decreased in shade-grown leaves, much lower than that of the full sunlight-grown leaves. On the contrary, F-o value was sharply increased. Neither of these parameters could completely recover till next morning. The photoinhibition was chronic and continued for about 4 d, while the F-v/F-m and the net photosynthetic rate ( P-n) continued to decline, then began to increase gradually 6 d later and turned stable after 10 - 12 d, appearing as an acclimation phenomenon. However, the final value of F-v/F-m and P-n did not reach the level as in those leaves grown in the full sunlight ever before. The final P-n was higher by 60% than that before exposure, but lower for more than 40% than that of the full sunlight-grown leaves. The most notable response of chloroplast pigment composition was a pronounced increase in the pool size of carotenoids in xanthophyll cycle over a period of 3 d. The results indicated that when shade-grown cotton seedlings were suddenly transferred to the full sunlight, the decline of F-v/F-m and P-n might associate with the damage of the PS II reaction center. During the light acclimation, photoprotective mechanisms such as the xanthophyll cycle-dependent energy dissipation were increased, so that photodamage in leaves transferred from low to high light might be reduced.
基金Project(51164001) supported by the National Natural Science Foundation of ChinaProject(0991082) supported by the Science and Technology Department of Guangxi,ChinaProject(GJR201147-12) supported by Guangxi Higher Education Institutes Talent Highland Innovation Team Scheme,China
文摘Pseudo glycolythiourea acid(PGA) was synthesized and used as depressant for flotation separation of Cu and Mo.The results indicate that a low amount of PGA has strong depression effect on chalcopyrite.Mo grade of 26.17% and recovery of 89.83% were achieved with rougher and scavenger one time and cleaners twice,while the recovery of Mo was deceased by 2% when Na2S was used as depressant.Measurement on adsorption of PGA on the mineral surface indicates that PGA and xanthate were adsorbed on mineral surface by competition,and PGA was adsorbed on chalcopyrite surface much stronger than on molybdenite surface.FTIR results indicate a chemical absorption process for PGA on chalcopyrite surface and a physical adsorption process on molybdenite surface.The frontier orbital calculation shows that the S atom is an active center,and the depression of PGA can be explained with the Fermi level of energy based on the electrochemical mechanism.
基金Supported by the Cooperation Subject(09003699)the Project of Jiangxi Education Department(GJJ12237)the Project of Science and Technology Department of Jiangxi(20122BBF60082)~~
文摘[Objective] To produce drug resistance, seek non-toxic environmental so as to change the current biological drugs that did not excessive use of antibiotics. [Methods] A strain of Bacillus was purified and isolated from fresh and healthy in- testines of grass carps. Biochemical identification was carried out by conventional bacterial biochemical test method. Two pairs of primers were designed, 16S rRNA detection and sequencing analysis were carried out. Drug sensitive test was carried out by agar diffusion method. In vitro inhibition test on Staphylococcus aureus was carried out by Oxford cup method. [Results] The isolated bacterium had basically the same biochemical characters as Bacillus subtilis; and the homology reached 100%. Thus, the isolated bacterium was identified to be Bacillus subtilis. It was insensitive to amoxicillin, ampicillin, penicillin G and so on, but sensitive to amikacin, cefalexin, ciprofloxacin and cefradine. The inhibitory effects of Bacillus subtilis on Staphylococ- cus aureus were significant. The minimum inhibitory concentration (MIC) was 2.8×10^8×2^-5/ml and minimum bactericidal concentration (MBC) was 2.8×10^8×2^-2/ml. [Conclusions] The isolated Bacillus subtilis could be used to prevent and control diseases caused by Staphylococcus aureus, and reduce the abuse of antibiotics.
基金Project(2008BAB34B01)supported by the National Key Technology R&D Program of China
文摘A novel synthesized reagent, O,O-bis(2,3-dihydroxypropyl) dithiophosphate (DHDTP), was investigated as depressant on the depression of chalcopyrite and galena, when ammonium dibutyl dithiophosphate (DDTP) was used as the collector in flotation tests. Zeta potential and adsorption measurement were performed to study the interaction between depressant and minerals. The flotation tests of two minerals show that DHDTP has slight depression on chalcopyrite in the whole pH range and strong depression on galena in the pH range of 6-10. When DHDTP dosage is increased, the recovery of galena decreases rapidly, while that of the chalcopyrite decreases slightly. The satisfied separation results of artificially mixed samples are that the copper grade and recovery rates of concentrate are 24.08% and 81%, respectively, when the pH is 6 with 278 mg/L DHDTP. Zeta potential and adsorption measurements show that DHDTP has more strongly adsorotion capacity to galena than chalcoovrite.
文摘In midday ginkgo ( Ginkgo biloba L.) leaves have to bear photon flux density over 1400 μmol·m -2 ·s -1 in combination with high temperatures around 35 ℃ at natural habitat. They show typical midday depression of stomatal conductance and of CO 2 assimilation rate. The zeaxanthin changes with light intensity during the day. The influence of the combination of strong light and temperature on photoinhibition was also examined in the laboratory. A low CO 2 internal conductance (31 mmol·m -2 ·s -1 ) was found in ginkgo leaves, which had been exposed to excessive light at temperature between 15 ℃ and 35 ℃ with reduced CO 2 (80 μL·L -1 ) or oxygen (2%) for 2 h, causing a low CO 2 concentration at the carboxylation site and a high proportion of photorespiration. The ratio of electron transport to CO 2 fixation was rather high in ginkgo (16 e -/CO 2 at 25 ℃) as compared with other plants. It increased with temperature also in 2% O 2 which could not be explained solely as due to change of photorespiration. The reduction of oxygen in 340 or 80 μL·L -1 CO 2 had no effect on the extent of photoinhibition at all temperatures, which indicated that electron flow caused by photorespiration in excess light was negligible in protective effect in ginkgo leaves. However, a decreased CO 2 concentration increased photoinhibition, especially at high temperature. It is concluded that the dissipation of excessive excitation energy in the PSⅡ antennae through the xanthophyll cycle may be the major protective mechanism to preventing from the deteriorated effects of strong light in ginkgo leaves.
基金The Chinese State Key Basic Research and Development Plan to KUANGT-Y
文摘Changes in the efficiency of the primary light energy conversion, fluorescence quenching parameters and contents of photosynthetic pigments were compared between two wheat ( Triticum aestivum L.) genotypes in response to high light stress. The contents of chlorophyll and carotenoid in “Jing_411' were slightly higher than those in “Xiaoyan_54'. Under high light stress, photoinhibition as indicated by a sustained decrease in PSⅡ photochemical efficiency was more pronounced in “Jing_411' than in “Xiaoyan_54'. The content of ascorbate and the activity of the deepoxidase were higher in “Xiaoyan_54' than in “Jing_411'. The genotypic difference in resistance to photoinhibition is related to the capacity to dissipate the excess energy nonradiatively.
文摘The performance of hydroxamic polyacrylamide(HPAM) in mineral flotation was tested on the samples of calcite, diaspore and pyrite. It is found that HPAM expresses intensive depression on pyrite and can be used as effective depressants for pyrite. The depression mechanism of HPAM to pyrite was investigated by the determination of contact angle, zeta potential, adsorptive capacity for collectors and infrared spectrum. A lower contact angle, more negative zeta potential, less xanthate adsorptive capacity, and the formation of chemical bonding were determined, which reveals that the strong chemical interactions exist between HPAM and pyrite surface. The group electronegativity of HPAM was calculated to explain the differences of interaction between reagent and minerals.
文摘AIM: To evaluate the anti-viral effect of emodin plus Astragalus polysaccharide (APS) in hepatitis B virus (HBV) transgenic mice.METHODS: Sixty HBV transgenic mice (HBV TGM) whose weight varied between 18 and 24 g were randomly divided into 3 groups, with 20 mice in each group. Group A was the normal control, where the mice were treated with physiological saline; group B was the positive control where the mice were treated with lamivudine solution (100 mL/kg per day). Group C was the experimental group where the mice were treated with physiological saline containing emodin and APS (57.59 mg/kg per day and 287.95 mg/kg per day, respectively). The mice were treated daily for 3 wk. After 1 wk recovery time, the mice were sacrifi ced and serum as well as liver tissues were collected for ELISA and histological examination.RESULTS: After 21 d treatment, HBV DNA levels in group B and group C significantly declined when compared with group A (P < 0.05). However, a signif icant increase in HBV DNA content was observed in group B, whereas this phenomenon was not observed in group C. A reduction in the contents of HBsAg, HBeAg and HBcAg in the mice from group B and C was observed when compared with group A.CONCLUSION: Emodin and APS have a weak but persistent inhibitory effect on HBV replication in vivo, which may function as a supplementary modality in the treatment of hepatitis B infection.
基金Project(2006AA06Z120) supported by High-Technology Research and Development Program of ChinaProject(1343-74334000028) supported by the Graduate Student Education Innovation Project of Central South University, China
文摘In order to selectively separate chalcopyrite from pyrite,the effect of organic depressant lignosulfonate calcium(LSC) on the flotation separation of chalcopyrite from pyrite was investigated by flotation tests. The depression mechanism was studied by Fourier-transform-infrared(FTIR) analysis. The flotation tests of single mineral show that LSC can depress the flotation of pyrite in a certain pH range,but it has little effect on chalcopyrite flotation. Flotation separation of a mixture of chalcopyrite and pyrite can be completed to obtain a copper concentrate grade up to 24.73% with a recovery of 80.36%. IR analysis shows that LSC and butyl xanthate compete in absorption on pyrite surface,and there exists an LSC characteristic peak on pyrite surface. There is little adsorption of LSC on chalcopyrite.
基金Supported by Projects of International Cooperation and Exchanges of Ministry of Science and Technology in China(2014DFR31230)
文摘Chinese seabuckthorn berry contains functional components. The berry was extracted by ethanol-water solution. MTT assay and growth rate method were applied to determine antibacterial ability in vitro of the extract solution. The antibacterial and antifungal assay indicated that the extract exhibited different degree of inhibitory activity. The result showed that the extract at a concentration of 1 250 mg/L had the maximum inhibitory effect against Escherichia coli, Bacillus subtilis, and Staphylococcus aureus. Inhibitory effect against B. subtilis was much larger than that against the other two bacterial species. MIC values(minimum inhibitory concentration) of the extract on three bacterial species were 5 000, 1 250, and 1 000 mg/L respectively. IC_(50)(50% inhibiting concentration) evaluation of Trichoderma viride, Rhizopus stolonifer, Aspergillus niger, Penicillium expansum, and Vintage Red indicated that the berry had the strongest inhibitory effect against P. expansum(5 520 mg/L), while it had the weakest inhibitory effect against R. stolonifer(18 870 mg/L). The results proved that seabuckthorn berry had highly effective and comprehensive antimicrobial function.
基金Supported by The Project of Heilongjiang Natural Science Foundation No. TD 2005-01Department of Health, Heilongjiang Province No. 2006-391
文摘AIM: To investigate the inhibitory effect and possible mechanism of action of schisandrin B in SC-B on gastric cancer cells in vitro.METHODS: SC-B consisted of schisandrin B, aloeemodin, and Astragalus polysaccharides. Exponentially growing human gastric cancer SGO7901 cells were divided into six treatment groups: (1) control group (RPMI 1640 medium); (2) negative control group (2% DMSO); (3) positive control group (50 mg/L 5-Fluorouracil, 5-FU); (4) low-dose group (LSC, final concentration of schisandrin B, 25 mg/L), (5) moderate-dose group (MSC, final concentration of schisandrin B, 50 mg/L); (6) highdose group (HSC, final concentration of schisandrin B, 100 mg/L). Follow-up was done at 12-48 h. An MTT (Methylthiazolyldiphenyl-tetrazolium bromide) assay was used to examine the inhibitory effect of SOB on gastric cancer cells. The mitosis index was assessed using an inverted microscope. Flow cytometry was used to visualize the cell cycle. An RT-PCR (Reverse transcription-Polymerase chain reaction) -based assay was used to detect mRNA expression for cyclin D1 and glyceraldehyde-3-phosphate dehydrogenase (GAPDH).RESULTS: The MTT assay showed that the number of living cells in the LSC, MSC and HSC groups was significantly smaller than that in the DMSO-treated group (P 〈 0.05) at 12-48 h. The inhibitory rate (IR) of the LSC group was 41.15% ± 3.86%, 59.24% ± 5.34% and 69.93% ± 7.81% at 12, 24 and 48 h, respectively. The IR of the MSC group was 42.82% ± 4.94%, 62.68% ± 7.58% and 71.79% ± 8.12% at 12, 24 and 48 h, respectively. The IR of the HSC group was 37.50% ± 3.21%, 40.34% ± 2.98% and 61.99% ± 4.88% at 12, 24 and 48 h, respectively. These results suggested that a moderate dosage had the most obvious inhibitory efficacy at 48 h. Compared to the DMSO group, the mitosis index of the LSC, MSC, HSC groups was greatly decreased (P 〈 0.05) at all time points. Any dose of SC-B suppressed mitosis within 12-48 h. Compared to the DMSO group, the percentage of cells in the G0/G1 phase of the MSC group was greatly increased, and that of the S + G2M phase was greatly decreased, while the percentage of cell inhibition (PCI) in the MSC group was greatly increased (P 〈 0.05). This suggested that SC-B could exclusively arrest cells in the G0/G1 phase. Cyclin D1 mRNA expression was lower in the MSC group than that in the DMSO group (P 〈 0.05).CONCLUSION: SC-B can inhibit the proliferation and aberrant mitosis of human gastric cancer SCG-7901 cells /n v/tro, This inhibitory effect may be due to the down- regulation of cyclin D1 mRNA expression, which causes cell cycle arrest of gastric cancer cells.
基金Project(50234010) supported by the National Natural Science Foundation of China
文摘A small molecular organic depressor glycerine-xanthate was synthesized. The effect of glycerine-xanthate on the flotation of sulfide minerals was investigated based on a function of pH value and concentration of glycerine-xanthate through flotation experiments in the presence and absence of Cu^2+. The results show that glycerinee-xanthate has a strong dressing effect on marmatite at pH〉6 and on arsenopyrite in weak acid and base conditions with butyl-xanthate as collector. In the presence of glycerine -xanthate, marmatite is activated by addition of Cu^2+, but arsenopyrite cannot be activated and remains unfloatable. So the selective separation can be achieved for two minerals. The depression of glycerine-xanthate on sulfide minerals was discussed based on the radical electronegative calculation and the theory of HSAB. Infrared spectrum shows that there are some -OH and-CSS-in glycedne-xanthate molecule, which competes with butyl-xanthate on the mineral surface. As a result of many hydrophilic groups in glycerine-xanthate, the surfaces of marmatite and arsenopyrite become hydrophilic, thus the flotation of marmatite and arsenopyrite is depressed. The collector is adsorbed preferentially on the surface of marmatite and it shows a better floatability in the presence of Cu^2+, whereas, the surface of arsenopyrite absorbs glycerine-xanthate and the flotation of arsenopyrite is depressed by glycerine-xanthate.
文摘AIM: To explore the effect of Astraga/us mongholicus polysaccharide (APS) on gene expression and mitogenactivated protein kinase (MAPK) transcriptional activity in intestinal epithelial cells (IEC). METHODS: IEC were divided into control group, lipopolysaccharide (LPS) group, LPS+ 50 μg/mL APS group, LPS+ 100 μg/mL APS group, LPS+ 200 μg/mL APS group, and LPS+ 500 μg/mL APS group. Levels of mRNAs in LPS-induced inflammatory factors, tumor necrosis factor (TNF)-α and interleukin (IL)-8, were measured by reverse transcription-polymerase chain reaction. MAPK protein level was measured by Western blotting. RESULTS: The levels of TNF-α and IL-8 mRNAs were significantly higher in IEC with LPS-induced damage than in control cells. APS significantly abrogated the LPS-induced expression of the TNF-α and IL-8 genes. APS did not block the activation of extracellular signal- regulated kinase or c Jun amino-terminal kinase, but inhibited the activation of p38, suggesting that APS inhibits LPS-induced production of TNF-α and IL-8 mRNAs, possibly by suppressing the p38 signaling pathway.CONCLUSION: APS-modulated bacterial productmediated p38 signaling represents an attractive strategy for prevention and treatment of intestinal inflammation.
基金The authors are grateful for the financial supports from the National Natural Science Foundation of China(No.51664020)the Natural Science Foundation of Jiangxi Province,China(No.20202ACBL214010)+1 种基金Open Foundation of State Key Laboratory of Mineral Processing,China(No.BGRIMM-KJSKL-2020-12)Open Foundation of Key Laboratory of Hunan Province for Clean and Efficient Utilization of Strategic Calcium-containing Mineral Resources,China(No.2018TP1002).
文摘Tragacanth gum(TG)was explored as a depressant to realize the flotation separation of molybdenite and talc.The flotation experiments indicated that when using potassium butyl xanthate(PBX)as a collector,molybdenite showed excellent floatability while talc was completely depressed by TG,thus realizing the flotation separation of the two minerals.X-ray photoelectron spectroscopy(XPS)analysis results showed that TG was adsorbed on molybdenite surface via chemisorption.The results of contact angle measurement,Fourier transform infrared(FTIR)spectroscopy,and time-of-flight secondary ion mass spectrometry(ToF-SIMS)indicated that the pre-adsorption of TG on molybdenite could not hinder the further chemisorption of PBX on molybdenite.Because PBX has no collecting ability on talc,the flotation separation of molybdenite and talc came true using PBX to collect molybdenite and TG to depress talc.
文摘Objective:To identify new favorable agents and develop novel approaches for the chemoprevention and treatment of superficial bladder cancer and investigate the effects of combination of retinoids and interferon α-2a on growth inhibition and apoptosis induction in bladder cancer cell lines. Methods:Four bladder cancer cell lines,grade 1 to 3,and two retinoids,all-trans-retinoic acid(ATRA),9-cis retinoic acid(9cRA),combined with interferon α-2a(INF),were used in the study.We compared the competence of these agents to inhibit growth,induce apoptosis,affect the expression of nuclear retinoid receptors,and modulate STAT1 protein. Results: Most of the bladder cancer cell lines were resistant to the effect of ATRA and 9cRA on growth inhibition and apoptosis induction,even at higher concentration(10 -5M).The effects of ATRA and 9c RA on cell growth and apoptosis were enhanced by INF α- 2a. Combination of ATRA and IFNα-2a induced RARβ and Stat 1 expression in three bladder cancer cell lines. Conclusion:The results demonstrated that INFα-2a synergize with the inhibitory effect of ATRA and 9c RA on the growth inhibition and apoptosis of bladder cancer cells in vitro,which suggested that it has a potential interest for the treatment of transitional cell carcinoma of bladder.