Background Perioperative disorder of magnesium, an important cation in the human body, may affect clinical anesthesia. The pharmacological data of propofol use, which is popularly used in the anesthesiology department...Background Perioperative disorder of magnesium, an important cation in the human body, may affect clinical anesthesia. The pharmacological data of propofol use, which is popularly used in the anesthesiology department and intensive care unit, is incomplete in Chinese patients. This study aimed to assess the effect of magnesium sulfate on the calculated plasma medial effective concentration (Cp5Ocal) of propofol at loss of response to command in Chinese females.展开更多
A detailed study on a small scale of the effect of phosphatization on the chemistry of marine cobalt-rich ferromanganese crusts supplies useful information for the evaluation and comprehensive utilization of crust min...A detailed study on a small scale of the effect of phosphatization on the chemistry of marine cobalt-rich ferromanganese crusts supplies useful information for the evaluation and comprehensive utilization of crust mineral resources. Sub-samples from top to bottom of a 10-cm thick sample from the NW Pacific Magellan seamount were taken at 5 mm intervals. The concentration profiles of ore-forming and rare earth elements show that obvious differences exist between young unphosphatized crusts and old phosphatized crusts. In the old crusts Fe, Mn, Si, Al, Zn, Mg, Co, Ni and Cu elements are depleted and Ca, P, Sr, Ba and Pb elements are enriched. The order of depletion is Co > Ni > Mg > Al > Mn > Si> Cu > Zn > Fe, while the order of enrichment is P > Ca > Ba > Pb > Sr. The phosphate mineral controls the concentration variation of the ore-forming elements in crusts and causes loss of the main ore-forming elements such as Co and Ni. The phosphatization also affects the abundance of REEs in the crusts. REEs are more abundant and the content of Ce in old crusts is higher than that in young crusts, however, the pattern of REEs and their fractionation characteristics in new and old crusts are not fundamentally changed. A Y-positive anomaly in old crusts has no relationship to the phosphatization.展开更多
Eu3+ doped SiO2 nano-crystalline glasses were prepared by sol-gel method. The broad peak of XRD pattern indicates an amorphous SiO2 matrix. The affection of anneal time and anneal temperatures on photoluminescence (PL...Eu3+ doped SiO2 nano-crystalline glasses were prepared by sol-gel method. The broad peak of XRD pattern indicates an amorphous SiO2 matrix. The affection of anneal time and anneal temperatures on photoluminescence (PL) properties of SiO2 glass under different Eu doping concentration were studied systematically. It is found that the optimized anneal time is about 3 h. The excitation spectra of 2% Eu3+ doped SiO2 glass powder were measured under various anneal temperatures, and the optimized anneal temperature is observed around 700℃. The fluorescence-quenching effect can be observed in the emission spectra when the annealing temperature exceeds 700℃. The emission spectra of different molar ratio dopants were measured at an annealed temperature of 500℃, and the concentration-quenching phenomenon has also been observed in SiO2 glass powder when the molar ratio of Eu3+ ion exceeds 3% . The result shows that the PL intensity approaches its maximum when the molar ratio of Eu3+ ions in the sample is about 3% . In addition, a comparatively stronger emission spectrum at wavelength of 703 nm which is corresponding to the energy transition 5D0→7F4 of Eu ions is also obtained.展开更多
The aim of this study was to evaluate the effects of low concentrations of DEHP and MEHP on steroidogenesis in a murine Leydig tumor cell line (MLTC-1) in vitro. The result of flow cytometry analysis revealed that t...The aim of this study was to evaluate the effects of low concentrations of DEHP and MEHP on steroidogenesis in a murine Leydig tumor cell line (MLTC-1) in vitro. The result of flow cytometry analysis revealed that the proportion of apoptotic cells was significantly increased after the exposure to DEHP. All three genes (P450scc, P450c17, and 38HSD) under study showed an increased expression following exposure to DEHP or MEHP, although some insignificant inhibitory effects appeared in the 10μmol/L treatment group as compared with the controls. It was also found that DEHP or MEHP stimulated INSL3 mRNA and protein especially in the 0.001 μmol/L treatment group. Testosterone secretions were stimulated after the exposure to DEHP or MEHP. Alterations of steroidogenic enzymes and INSL3 in MLTC-1 cells might be involved in the biphasic effects of DEHP/MEHP on androgen production.展开更多
Adsorption/desorption in a new Zn(Ⅱ)-TiO2 adsorption system was investigated at different particle concentrations (Cp). TEM, SEM and XRD analyses revealed that the TiO2 particles were an aggregation of nano-sized...Adsorption/desorption in a new Zn(Ⅱ)-TiO2 adsorption system was investigated at different particle concentrations (Cp). TEM, SEM and XRD analyses revealed that the TiO2 particles were an aggregation of nano-sized (approximately 10 nm) pure anatase-type TiO2. Adsorption experiments were carried out with particle concentrations of 100, 400 and 1000 mg/L, and their adsorption isotherms were found to decline successively, showing an obvious Cp effect. Desorption experiments indicated that adsorption in this system was irreversible, and the irreversibility increased with increasing Cp. These phenomena could be explained by the MEA (metastable equilibrium adsorption) theory and the Cp effect could be modeled well with an MEA-Freundlich-type Cp effect isotherm equation. This study may heln understand environmental behavior of contaminants on ultrafine natural particles.展开更多
Transparent conductive cadmium indium oxide films (CdIn2O4) were prepared by r.f. reactive sputtering from Cd-In alloy targets under an Ar-O2 atmosphere. Electrical conductivity of the order of 105Ω-1.m-1 and the opt...Transparent conductive cadmium indium oxide films (CdIn2O4) were prepared by r.f. reactive sputtering from Cd-In alloy targets under an Ar-O2 atmosphere. Electrical conductivity of the order of 105Ω-1.m-1 and the optical transmission as high as 94% are easily attained by postdeposition annealing treatment. The effects of oxygen concentration in the reactive gas mixture and post-deposition annealing treatment on the optical transmittance as well as optical parameters, such as refractive index (n), extinction coefficient (k), real part (ε') and imaginary part (ε') of the dielectric constant, were studied in the visible and near-infrared region. The highfrequency dielectric constant ε∞ the plasma frequency ωP, and the conduction band effective mass mc of different samples were also investigated展开更多
This paper presents the analysis of two-layer cilia induced flow of Phan-Thien-Tanner(PTT) fluid with thermal and concentration effect.The Phan-Thien-Tanner fluid model has been used in the analogy of mucus present in...This paper presents the analysis of two-layer cilia induced flow of Phan-Thien-Tanner(PTT) fluid with thermal and concentration effect.The Phan-Thien-Tanner fluid model has been used in the analogy of mucus present in the respiratory tract.The two-layer model approach was used due to the Peri Ciliary liquid Layer(PCL) and Airway Ciliary Layer(ACL) present on the epithelium cell in respiratory tract.The mathematical modelling of two-layer flow problem was simplified using long wavelength and small Reynold ’ s number approximation.The resulting differential equation with moving boundary gives exact solution for velocity,temperature and concentration profiles in two layers.The change in pressure has calculated by the results of velocity profile,also the pressure rise was evaluated by the numerical integration of pressure gradient along the channel wall.The impact of physical parameters on pressure rise,velocity,temperature and concentration profile was explained by the graphs.It can be seen from graphs that velocity and temperature profile are maximum in the inner layer of fluid(PCL) and concentration profile is maximum at outer layers of fluid(ACL).展开更多
Effects of abrasive concentration on material removal rate CMRR) and surtace quality m the chemical mecnamcal polishing (CMP) of light-emitting diode sapphire substrates are investigated. Experimental results show ...Effects of abrasive concentration on material removal rate CMRR) and surtace quality m the chemical mecnamcal polishing (CMP) of light-emitting diode sapphire substrates are investigated. Experimental results show that the MRR increases linearly with the abrasive concentration, while the rms roughness decreases with the increasing abrasive concentration. In addition, the in situ coefficient of friction (COF) is also conducted during the sapphire polishing process. The results present that COF increases sharply with the abrasive concentration up to 20 wt% and then shows a slight decrease from 20wt% to 40wt%. Temperature is a product of the friction force that is proportional to COF, which is an indicator for the mechanism of the sapphire CMP.展开更多
Superoxide dismutase(SOD) is a crucial antioxidant enzyme playing the first defense line in antioxidant pathways against reactive oxygen species in various organisms including marine invertebrates. There exist mainl...Superoxide dismutase(SOD) is a crucial antioxidant enzyme playing the first defense line in antioxidant pathways against reactive oxygen species in various organisms including marine invertebrates. There exist mainly two specific forms, Cu/Zn-SOD(SOD1) and Mn-SOD(SOD2), in eukaryotes. SODs are known to be concurrently modulated by a variety of environmental stressors. By using central composite experimental design and response surface method, the joint effects of water temperature(18–34°C) and copper ion concentration(0.1–1.5 mg/L) on the total SOD activity in the digestive gland of Crassostrea ariakensis were studied. The results showed that the linear effect of temperature was highly significant(P〈0.01), the quadratic effect of temperature was significant(P〈0.05); the linear effect of copper ion concentration was not significant(P〉0.05), while the quadratic effect of copper ion concentration was highly significant(P〈0.01); the interactive effect of temperature and copper ion concentration was not significant(P〉0.05); the effect of temperature was greater than that of copper ion concentration. The model equation of digestive gland SOD enzyme activity towards the two factors of interest was established, with R2 and predictive R2 as high as 0.961 6 and 0.820 7, respectively, suggesting that the goodness-offit to experimental data be very satisfactory, and could be applied to prediction of digestive gland SOD activity in C. ariakensis under the conditions of the experiment. Our results would be conducive to addressing the health of aquatic animals and/or to detecting environmental problems by taking SOD as a potential bioindicator.展开更多
Under bilateral cooperation between the United States of America and the People's Republic of China, a series of research cruises were conducted over the western Pacific Ocean. It was found that a) the non-sea-sal...Under bilateral cooperation between the United States of America and the People's Republic of China, a series of research cruises were conducted over the western Pacific Ocean. It was found that a) the non-sea-salt sulfate aerosol particles are the major source of cloud condensation nuclei, b) the population of clouds and the total albedo are proportional to the concentration of condensation nuclei and consequently to the concentration of the non-sea-salt aerosol particles, and c) the amount of rainfall is inversely proportional to the concentration of non-sea-salt sulfate aerosol particles. It seems that anthropogenic sulfate aerosol particles affect the regional planetary albedo and climate and that the contribution from biogenically derived sulfate aerosol particles is of lesser importance.展开更多
In this current paper, the exposure time effects on four endocrine disruptors and teleost fishes were evaluated using the reduced life expectancy (RLE) model based on the effect concentration (EC<sub>50</sub&...In this current paper, the exposure time effects on four endocrine disruptors and teleost fishes were evaluated using the reduced life expectancy (RLE) model based on the effect concentration (EC<sub>50</sub>) of available literature published. The result on the regression analysis over different exposure times has demonstrated that the EC<sub>50</sub> of hepatic biomarkers falls with increasing exposure times in a predictable manner. The slopes of the regression equations reflect the strength of the toxic effects on the various teleost fish. The EC<sub>50</sub> reduction over time can be interpreted based on the bioconcentration process, which can be used to understand transfer routes of the compounds from water to fish body. RLE model also provides useful information in assessing the toxic effects on fish life expectancy as a result of the occurrence of compounds.展开更多
Pyrophyllite (H2Al2,Si4 O22, ) dust (P-dust) is a mixture of silica (10-40% ), differentproportions of a luminium oxide (Al2O3 ), and various metal compounds. People with occupa-tions known to be associated with expos...Pyrophyllite (H2Al2,Si4 O22, ) dust (P-dust) is a mixture of silica (10-40% ), differentproportions of a luminium oxide (Al2O3 ), and various metal compounds. People with occupa-tions known to be associated with exposure to P-dust include miners, other industrial workersand persons engaged in artistic carving. Currently, little is known about pyrophyllite pneumo-coniosis from P-dust. This study was designed to investigate the hazardous effects of P-dustand to suggest a maximum allowable concentration (MAC) of the dust.This.study included four parts: (i) Occupational epidemiology surveys in 781 workersfrom 1 pyrophyllite mine (PM) and four pyrophyllite carving mills (PCM), with a registra-tion rate of 98 %. (ii) In vitro studies: Six groups of rats were expeed to different levels ofP-dust; the cytotoxicity of P-dust on rat alveolar macrophages (AM) was investigated by de-termining the potassium'content of AM and the activity levels of lactate dehydrogenase (LDH)in AM culture fluid. (iii) Mineralogical analysis of P-dust: The contents of silica (SiO2 ), alu-minium (Al), ferrum (Fe), niikel (Ni), zinc (Zn) and copper (Cu) in hath PM-dust andPCMdust were determined. (iv ) Determination of P-dust MAC: Using the life-talbemethod, an investigation of the hygiene standard of P-dust was carried out in 625 workers ex-POSed to either PM-dust or PCM-dust, uPon whom routine radiographs were Performed.The results suggest that the risk of developing pneumoconiosis from pyrophyllite dust issignificantly higher for PM workers than for PCM workers. The prevalence rate of PCM-dustpneumoconiosis is significantly higher in men than in women. The content of SiO2 and AlO3in the mixture of P-dust is the most important factor in the etiology of pyrophyllitosis. De-pending on the different P-dust MAC values, we suggest that 2 rng/m3 and 4 mg/m' shouldbe considered as the MAC for PM-dust and PCM-dust, respectively, and 3 mg/m' fOr P-dust. We believe that establishing different hygiene standards is more accurate even thoughworkers are exposured to the 'same' dust展开更多
Relative tillering rate(RTR)increased linear-ly with the increasing of leaf N concentration(NLV)has been already reported.To testwhether this relationship could be used toquantitatively explain the difference in tille...Relative tillering rate(RTR)increased linear-ly with the increasing of leaf N concentration(NLV)has been already reported.To testwhether this relationship could be used toquantitatively explain the difference in tilleringamong a wide range of N application,field ex- periments were conducted at the IRRI farm,Los Banos,Laguna,the Philippines.Two in- dica cultivars,IR 72 and IR68284H wereused.For each cultivar,12 treatments includ- ing 4 N levels(0,60,120,and 180kgN·ha)and 3 transplanting spacing(30×20,20×20,and 10×20cm)were arranged in a ran-domized split-plot design with 4 replications.The N treatments were designated as mainplots and spacings as subplots.Fourteen-day-old seedlings were transplanted with 3seedlings per hill.The subplot area was 20m~2.Nitrogen fertilizer was applied as basal,atmidtillering,and at panicle initiation in threeequal splits.P,K,and Zn were applied asbasal at normal dosage.The field was flooded.Plant samples were taken every 7-14 d from 14d after transplanting to flower展开更多
We studied the effect of agar concentration inmedia on callus induction rate and green plant-let regeneration frequency in rice.Materialswere Fgeneration of indica/indica or indica/japonica,which were 96E76(Hei’e/Zha...We studied the effect of agar concentration inmedia on callus induction rate and green plant-let regeneration frequency in rice.Materialswere Fgeneration of indica/indica or indica/japonica,which were 96E76(Hei’e/Zhaiye- qing 8),96E80[(IR 24/Guanglu'ai 4//Zhongnan’ai)/Yifengzao],96E86(Zhong- munong 9/Zhaiyeqing 8).The induction mediaused was M8+2mg/L 2,4-D,and agar con-centrations were 0.6%,0.8%,and 1.0%,respectively.Regeneration media was MS+2mg/L KT+0.5mg/L IAA+0.5mg/LNAA,and agar concentrations were 0.6% and1.0%.Results indicated that the calli induc-展开更多
Objective To investigate the effect of exogenous thyroid hormone on serum NO and iNOS activity of intestinal mucosa in septic rats. Methods Septic model was established by cecal ligation puncture (CLP) in male SD rats...Objective To investigate the effect of exogenous thyroid hormone on serum NO and iNOS activity of intestinal mucosa in septic rats. Methods Septic model was established by cecal ligation puncture (CLP) in male SD rats. Triiodothyronine ( T3 ) was administered intraperitoneally to correct the low T3 syndrome of septic rats. Blood was collected to examine serum NO and thyroid hormone concentration. Intestinal mucosa iNOS activity was assayed using immunochemical stain. Results Mortality rate in the prevention group was significantly lower than the septic group (Log rank = 3. 85, P 【 0.05). Serum NO concentration was significantly lower in the prevention group (F=19.6,F【0.01). The degree of inflammatory injury of intestinal mucosa was much milder in the prevention group than in the septic group (x2 = 5.303,P【0. 05). Mucosa iNOS activity was also significantly lower in the prevention group (x2 = 4. 876, P【0. 01). Conclusion Thyroid hormone protects the intestinal mucosa barrier inhibiting the expression of展开更多
BACKGROUND Propofol is a short-acting,rapid-recovering anesthetic widely used in sedated colonoscopy for the early detection,diagnosis and treatment of colon diseases.However,the use of propofol alone may require high...BACKGROUND Propofol is a short-acting,rapid-recovering anesthetic widely used in sedated colonoscopy for the early detection,diagnosis and treatment of colon diseases.However,the use of propofol alone may require high doses to achieve the induction of anesthesia in sedated colonoscopy,which has been associated with anesthesia-related adverse events(AEs),including hypoxemia,sinus bradycardia,and hypotension.Therefore,propofol co-administrated with other anesthetics has been proposed to reduce the required dose of propofol,enhance the efficacy,and improve the satisfaction of patients receiving colonoscopy under sedation.AIM To evaluate the efficacy and safety of propofol target-controlled infusion(TCI)in combination with butorphanol for sedation during colonoscopy.METHODS In this controlled clinical trial,a total of 106 patients,who were scheduled for sedated colonoscopy,were prospectively recruited and assigned into three groups to receive different doses of butorphanol before propofol TCI:Low-dose butorphanol group(5μg/kg,group B1),high-dose butorphanol group(10μg/kg,group B2),and control group(normal saline,group C).Anesthesia was achieved by propofol TCI.The primary outcome was the median effective concentration(EC50)of propofol TCI,which was measured using the up-and-down sequential method.The secondary outcomes included AEs in perianesthesia and recovery characteristics.RESULTS The EC50 of propofol for TCI was 3.03μg/mL[95%confidence interval(CI):2.83-3.23μg/mL]in group B2,3.41μg/mL(95%CI:3.20-3.62μg/mL)in group B1,and 4.05μg/mL(95%CI:3.78-4.34μg/mL)in group C.The amount of propofol necessary for anesthesia was 132 mg[interquartile range(IQR),125-144.75 mg]in group B2 and 142 mg(IQR,135-154 mg)in group B1.Furthermore,the awakening concentration was 1.1μg/mL(IQR,0.9-1.2μg/mL)in group B2 and 1.2μg/mL(IQR,1.025-1.5μg/mL)in group B1.Notably,the propofol TCI plus butorphanol groups(groups B1 and B2)had a lower incidence of anesthesia AEs,when compared to group C.Furthermore,no significant differences were observed in the rates of AEs in perianesthesia,including hypoxemia,sinus bradycardia,hypotension,nausea and vomiting,and vertigo,among group C,group B1 and group B2.CONCLUSION The combined use with butorphanol reduces the EC50 of propofol TCI for anesthesia.The decrease in propofol might contribute to the reduced anesthesia-related AEs in patients undergoing sedated colonoscopy.展开更多
The channel lateral pocket or halo region of NMOSFET characterized by interface state R G current of a forward gated diode has been investigated numerically for the first time.The result of numerical analysis demons...The channel lateral pocket or halo region of NMOSFET characterized by interface state R G current of a forward gated diode has been investigated numerically for the first time.The result of numerical analysis demonstrates that the effective surface doping concentration and the interface state density of the pocket or halo region are interface states R G current peak position dependent and amplitude dependent,respectively.It can be expressed quantitatively according to the device physics knowledge,thus,the direct characterization of the interface state density and the effective surface doping concentration of the pocket or halo becomes very easy.展开更多
Chlorpyrifos and dimethoate are overused agricultural pesticides that can trigger trophic cascades, resulting in toxicity to both terrestrial and aquatic organisms as well as altered ecosystems. In previous studies, s...Chlorpyrifos and dimethoate are overused agricultural pesticides that can trigger trophic cascades, resulting in toxicity to both terrestrial and aquatic organisms as well as altered ecosystems. In previous studies, substantial attention has been given to the effects of pesticides on vertebrate species and, to a lesser extent, species of zooplankton. The present study was designed to show that the fission time effective concentration in ciliates is a potential aquatic detection index for environmental monitoring. The ciliate Urostyla grandis was treated with doses of chlorpyrifos and dimethoate. After exposed to the pesticides, the LC_(50)(i.e., concentration that killed 50% of the ciliate cells within 24 h) values were 0.029 mg L^(-1) for chlorpyrifos and 0.0685 mg L^(-1) for dimethoate. The fission time effective concentrations after 168 h of exposure were 0.0075–0.0093 mg L^(-1) for chlorpyrifos and 0.2640–0.2750 mg L^(-1) for dimethoate. These results show that the fission time effective concentration is lower than the LC_(50) value in ciliates, indicating that fission time effective concentration is more suitable than the LC_(50) value for environmental monitoring using ciliates. The effects of chlorpyrifos and dimethoate on ciliate cell ultrastructures included agglutination of chromatin in the macronucleus, protruded and discontinuous macronuclear and micronuclear membranes, loss of integrity of mitochondrial membranes and contents, and abscission and deformation of the adoral zone of membranelles.展开更多
This study aimed to develop original laboratory culture and sediment toxicity testing protocols for the freshwater gastropod Bellamya aeruginosa (Reeve), a new potential species for sediment toxicity testing. B. aer...This study aimed to develop original laboratory culture and sediment toxicity testing protocols for the freshwater gastropod Bellamya aeruginosa (Reeve), a new potential species for sediment toxicity testing. B. aeruginosa was successfully cultured with an effective culture system under proposed laboratory conditions. Optimal ad libitum feeding levels for larvae, juveniles, and adults were 2.0, 6.0, and 16.0 mg fish food/(snall.day), respectively. Mean survival rates of juveniles were higher than 90%, The snails could be sexed at 9 weeks of age, and their generation time is approximately 4 months. Reproduction continued all year around; the mean fecundity was 0.55 newborn/(female.day). The utility of this species for bioassays was evaluated in both 10-day and 28-day case studies with artificial sediments. The 10-day LC50 of Cu for larvae was 480 μg/g dry weight (dw), and the lowest observed effects concentration of Cu for survival and growth of larvae was 195 μg/g dw. Survival and growth are reliable indicators of acute toxicity. Larvae accumulated more Cu than adults. B. aeruginosa exhibited a higher sensitivity to Cu exposure than standard test species (Hyalella azteca and Chironomus tentans). The 28-day test of sediment toxicity with adults showed that fecundity was a robust endpoint indicator of reproductive toxicity, and the biochemical endpoints of superoxide dismutase, catalase, and glutathione could be used as sensitive biomarkers for Cu-induced oxidative damage. B. aeruginosa can be therefore recommended as a candidate for the standardization of the freshwater sediment toxicity test protocol.展开更多
The phytotoxicity of chlorobenzoic acids(CBAs) was studied and the biochemical endpoints' suitability and sensibility was evaluated. Two terrestrial plant species in the same family were exposed to different conce...The phytotoxicity of chlorobenzoic acids(CBAs) was studied and the biochemical endpoints' suitability and sensibility was evaluated. Two terrestrial plant species in the same family were exposed to different concentrations of CBAS and tested their germination according to the guideline of Organization for Economic Cooperation and Development(OECP, 1984). The results showed that CBA dose-inhibition rate of classical endpoint had the distinct linear relationship in the range of 10%—50% inhibition rate for root elongation(p<0.01), and the dose variances of CBAs had the greater influence on the inhibition rate of germination than on inhibition rate of root elongation. The CBA dose half effect concentration-inhibition rate of two antioxidant enzyme activity superoxide dismutase(SOD) and catalase (CAT) had the quadratic relationship, and CBA dose-inhibition rate of the peroxides(POD) activity had the linear relationship(p<0.05). Comparing the half effect concentration (EC_ 50) of two kinds of endpoints, the POD activity was more sensitive than classical endpoint, however, SOD and CAT activity were not sensitive in the experiment.展开更多
文摘Background Perioperative disorder of magnesium, an important cation in the human body, may affect clinical anesthesia. The pharmacological data of propofol use, which is popularly used in the anesthesiology department and intensive care unit, is incomplete in Chinese patients. This study aimed to assess the effect of magnesium sulfate on the calculated plasma medial effective concentration (Cp5Ocal) of propofol at loss of response to command in Chinese females.
基金supported by grant DY95-08-05 from the China Ocean Mineral Resources R&D Associationthe National Natural Science Foundation of China(Grant 40373002).
文摘A detailed study on a small scale of the effect of phosphatization on the chemistry of marine cobalt-rich ferromanganese crusts supplies useful information for the evaluation and comprehensive utilization of crust mineral resources. Sub-samples from top to bottom of a 10-cm thick sample from the NW Pacific Magellan seamount were taken at 5 mm intervals. The concentration profiles of ore-forming and rare earth elements show that obvious differences exist between young unphosphatized crusts and old phosphatized crusts. In the old crusts Fe, Mn, Si, Al, Zn, Mg, Co, Ni and Cu elements are depleted and Ca, P, Sr, Ba and Pb elements are enriched. The order of depletion is Co > Ni > Mg > Al > Mn > Si> Cu > Zn > Fe, while the order of enrichment is P > Ca > Ba > Pb > Sr. The phosphate mineral controls the concentration variation of the ore-forming elements in crusts and causes loss of the main ore-forming elements such as Co and Ni. The phosphatization also affects the abundance of REEs in the crusts. REEs are more abundant and the content of Ce in old crusts is higher than that in young crusts, however, the pattern of REEs and their fractionation characteristics in new and old crusts are not fundamentally changed. A Y-positive anomaly in old crusts has no relationship to the phosphatization.
基金Project supported by the National Natural Science Foundation of China (50272063)
文摘Eu3+ doped SiO2 nano-crystalline glasses were prepared by sol-gel method. The broad peak of XRD pattern indicates an amorphous SiO2 matrix. The affection of anneal time and anneal temperatures on photoluminescence (PL) properties of SiO2 glass under different Eu doping concentration were studied systematically. It is found that the optimized anneal time is about 3 h. The excitation spectra of 2% Eu3+ doped SiO2 glass powder were measured under various anneal temperatures, and the optimized anneal temperature is observed around 700℃. The fluorescence-quenching effect can be observed in the emission spectra when the annealing temperature exceeds 700℃. The emission spectra of different molar ratio dopants were measured at an annealed temperature of 500℃, and the concentration-quenching phenomenon has also been observed in SiO2 glass powder when the molar ratio of Eu3+ ion exceeds 3% . The result shows that the PL intensity approaches its maximum when the molar ratio of Eu3+ ions in the sample is about 3% . In addition, a comparatively stronger emission spectrum at wavelength of 703 nm which is corresponding to the energy transition 5D0→7F4 of Eu ions is also obtained.
基金supported by the National Natural Science Foundation of China(No.81273028)
文摘The aim of this study was to evaluate the effects of low concentrations of DEHP and MEHP on steroidogenesis in a murine Leydig tumor cell line (MLTC-1) in vitro. The result of flow cytometry analysis revealed that the proportion of apoptotic cells was significantly increased after the exposure to DEHP. All three genes (P450scc, P450c17, and 38HSD) under study showed an increased expression following exposure to DEHP or MEHP, although some insignificant inhibitory effects appeared in the 10μmol/L treatment group as compared with the controls. It was also found that DEHP or MEHP stimulated INSL3 mRNA and protein especially in the 0.001 μmol/L treatment group. Testosterone secretions were stimulated after the exposure to DEHP or MEHP. Alterations of steroidogenic enzymes and INSL3 in MLTC-1 cells might be involved in the biphasic effects of DEHP/MEHP on androgen production.
基金Project supported by the National Natural Science Foundation of China(No.20537020)the "Hundred Talent Scientist Program" of the Chinese Academy of Sciences.
文摘Adsorption/desorption in a new Zn(Ⅱ)-TiO2 adsorption system was investigated at different particle concentrations (Cp). TEM, SEM and XRD analyses revealed that the TiO2 particles were an aggregation of nano-sized (approximately 10 nm) pure anatase-type TiO2. Adsorption experiments were carried out with particle concentrations of 100, 400 and 1000 mg/L, and their adsorption isotherms were found to decline successively, showing an obvious Cp effect. Desorption experiments indicated that adsorption in this system was irreversible, and the irreversibility increased with increasing Cp. These phenomena could be explained by the MEA (metastable equilibrium adsorption) theory and the Cp effect could be modeled well with an MEA-Freundlich-type Cp effect isotherm equation. This study may heln understand environmental behavior of contaminants on ultrafine natural particles.
文摘Transparent conductive cadmium indium oxide films (CdIn2O4) were prepared by r.f. reactive sputtering from Cd-In alloy targets under an Ar-O2 atmosphere. Electrical conductivity of the order of 105Ω-1.m-1 and the optical transmission as high as 94% are easily attained by postdeposition annealing treatment. The effects of oxygen concentration in the reactive gas mixture and post-deposition annealing treatment on the optical transmittance as well as optical parameters, such as refractive index (n), extinction coefficient (k), real part (ε') and imaginary part (ε') of the dielectric constant, were studied in the visible and near-infrared region. The highfrequency dielectric constant ε∞ the plasma frequency ωP, and the conduction band effective mass mc of different samples were also investigated
文摘This paper presents the analysis of two-layer cilia induced flow of Phan-Thien-Tanner(PTT) fluid with thermal and concentration effect.The Phan-Thien-Tanner fluid model has been used in the analogy of mucus present in the respiratory tract.The two-layer model approach was used due to the Peri Ciliary liquid Layer(PCL) and Airway Ciliary Layer(ACL) present on the epithelium cell in respiratory tract.The mathematical modelling of two-layer flow problem was simplified using long wavelength and small Reynold ’ s number approximation.The resulting differential equation with moving boundary gives exact solution for velocity,temperature and concentration profiles in two layers.The change in pressure has calculated by the results of velocity profile,also the pressure rise was evaluated by the numerical integration of pressure gradient along the channel wall.The impact of physical parameters on pressure rise,velocity,temperature and concentration profile was explained by the graphs.It can be seen from graphs that velocity and temperature profile are maximum in the inner layer of fluid(PCL) and concentration profile is maximum at outer layers of fluid(ACL).
基金Supported by the National Major Scientific and Technological Special Project during the Twelfth Five-year Plan Period under Grant No 2011ZX02704the National Natural Science Foundation of China under Grant No 51205387the Science and Technology Commission of Shanghai under Grant Nos llnm0500300 and 14XD1425300
文摘Effects of abrasive concentration on material removal rate CMRR) and surtace quality m the chemical mecnamcal polishing (CMP) of light-emitting diode sapphire substrates are investigated. Experimental results show that the MRR increases linearly with the abrasive concentration, while the rms roughness decreases with the increasing abrasive concentration. In addition, the in situ coefficient of friction (COF) is also conducted during the sapphire polishing process. The results present that COF increases sharply with the abrasive concentration up to 20 wt% and then shows a slight decrease from 20wt% to 40wt%. Temperature is a product of the friction force that is proportional to COF, which is an indicator for the mechanism of the sapphire CMP.
基金The Guangdong Province Education Department under contract No.GCZX-A0909the Guangdong Province Ocean and Fisheries Science & Technology Extension Project under contract No.20120980+1 种基金the Guangdong Province Industry-University-Science Partnership Project under contract No.20110908the Science&Technology Project of Huaiyin Normal University under contract No.WH0031
文摘Superoxide dismutase(SOD) is a crucial antioxidant enzyme playing the first defense line in antioxidant pathways against reactive oxygen species in various organisms including marine invertebrates. There exist mainly two specific forms, Cu/Zn-SOD(SOD1) and Mn-SOD(SOD2), in eukaryotes. SODs are known to be concurrently modulated by a variety of environmental stressors. By using central composite experimental design and response surface method, the joint effects of water temperature(18–34°C) and copper ion concentration(0.1–1.5 mg/L) on the total SOD activity in the digestive gland of Crassostrea ariakensis were studied. The results showed that the linear effect of temperature was highly significant(P〈0.01), the quadratic effect of temperature was significant(P〈0.05); the linear effect of copper ion concentration was not significant(P〉0.05), while the quadratic effect of copper ion concentration was highly significant(P〈0.01); the interactive effect of temperature and copper ion concentration was not significant(P〉0.05); the effect of temperature was greater than that of copper ion concentration. The model equation of digestive gland SOD enzyme activity towards the two factors of interest was established, with R2 and predictive R2 as high as 0.961 6 and 0.820 7, respectively, suggesting that the goodness-offit to experimental data be very satisfactory, and could be applied to prediction of digestive gland SOD activity in C. ariakensis under the conditions of the experiment. Our results would be conducive to addressing the health of aquatic animals and/or to detecting environmental problems by taking SOD as a potential bioindicator.
文摘Under bilateral cooperation between the United States of America and the People's Republic of China, a series of research cruises were conducted over the western Pacific Ocean. It was found that a) the non-sea-salt sulfate aerosol particles are the major source of cloud condensation nuclei, b) the population of clouds and the total albedo are proportional to the concentration of condensation nuclei and consequently to the concentration of the non-sea-salt aerosol particles, and c) the amount of rainfall is inversely proportional to the concentration of non-sea-salt sulfate aerosol particles. It seems that anthropogenic sulfate aerosol particles affect the regional planetary albedo and climate and that the contribution from biogenically derived sulfate aerosol particles is of lesser importance.
文摘In this current paper, the exposure time effects on four endocrine disruptors and teleost fishes were evaluated using the reduced life expectancy (RLE) model based on the effect concentration (EC<sub>50</sub>) of available literature published. The result on the regression analysis over different exposure times has demonstrated that the EC<sub>50</sub> of hepatic biomarkers falls with increasing exposure times in a predictable manner. The slopes of the regression equations reflect the strength of the toxic effects on the various teleost fish. The EC<sub>50</sub> reduction over time can be interpreted based on the bioconcentration process, which can be used to understand transfer routes of the compounds from water to fish body. RLE model also provides useful information in assessing the toxic effects on fish life expectancy as a result of the occurrence of compounds.
文摘Pyrophyllite (H2Al2,Si4 O22, ) dust (P-dust) is a mixture of silica (10-40% ), differentproportions of a luminium oxide (Al2O3 ), and various metal compounds. People with occupa-tions known to be associated with exposure to P-dust include miners, other industrial workersand persons engaged in artistic carving. Currently, little is known about pyrophyllite pneumo-coniosis from P-dust. This study was designed to investigate the hazardous effects of P-dustand to suggest a maximum allowable concentration (MAC) of the dust.This.study included four parts: (i) Occupational epidemiology surveys in 781 workersfrom 1 pyrophyllite mine (PM) and four pyrophyllite carving mills (PCM), with a registra-tion rate of 98 %. (ii) In vitro studies: Six groups of rats were expeed to different levels ofP-dust; the cytotoxicity of P-dust on rat alveolar macrophages (AM) was investigated by de-termining the potassium'content of AM and the activity levels of lactate dehydrogenase (LDH)in AM culture fluid. (iii) Mineralogical analysis of P-dust: The contents of silica (SiO2 ), alu-minium (Al), ferrum (Fe), niikel (Ni), zinc (Zn) and copper (Cu) in hath PM-dust andPCMdust were determined. (iv ) Determination of P-dust MAC: Using the life-talbemethod, an investigation of the hygiene standard of P-dust was carried out in 625 workers ex-POSed to either PM-dust or PCM-dust, uPon whom routine radiographs were Performed.The results suggest that the risk of developing pneumoconiosis from pyrophyllite dust issignificantly higher for PM workers than for PCM workers. The prevalence rate of PCM-dustpneumoconiosis is significantly higher in men than in women. The content of SiO2 and AlO3in the mixture of P-dust is the most important factor in the etiology of pyrophyllitosis. De-pending on the different P-dust MAC values, we suggest that 2 rng/m3 and 4 mg/m' shouldbe considered as the MAC for PM-dust and PCM-dust, respectively, and 3 mg/m' fOr P-dust. We believe that establishing different hygiene standards is more accurate even thoughworkers are exposured to the 'same' dust
文摘Relative tillering rate(RTR)increased linear-ly with the increasing of leaf N concentration(NLV)has been already reported.To testwhether this relationship could be used toquantitatively explain the difference in tilleringamong a wide range of N application,field ex- periments were conducted at the IRRI farm,Los Banos,Laguna,the Philippines.Two in- dica cultivars,IR 72 and IR68284H wereused.For each cultivar,12 treatments includ- ing 4 N levels(0,60,120,and 180kgN·ha)and 3 transplanting spacing(30×20,20×20,and 10×20cm)were arranged in a ran-domized split-plot design with 4 replications.The N treatments were designated as mainplots and spacings as subplots.Fourteen-day-old seedlings were transplanted with 3seedlings per hill.The subplot area was 20m~2.Nitrogen fertilizer was applied as basal,atmidtillering,and at panicle initiation in threeequal splits.P,K,and Zn were applied asbasal at normal dosage.The field was flooded.Plant samples were taken every 7-14 d from 14d after transplanting to flower
文摘We studied the effect of agar concentration inmedia on callus induction rate and green plant-let regeneration frequency in rice.Materialswere Fgeneration of indica/indica or indica/japonica,which were 96E76(Hei’e/Zhaiye- qing 8),96E80[(IR 24/Guanglu'ai 4//Zhongnan’ai)/Yifengzao],96E86(Zhong- munong 9/Zhaiyeqing 8).The induction mediaused was M8+2mg/L 2,4-D,and agar con-centrations were 0.6%,0.8%,and 1.0%,respectively.Regeneration media was MS+2mg/L KT+0.5mg/L IAA+0.5mg/LNAA,and agar concentrations were 0.6% and1.0%.Results indicated that the calli induc-
文摘Objective To investigate the effect of exogenous thyroid hormone on serum NO and iNOS activity of intestinal mucosa in septic rats. Methods Septic model was established by cecal ligation puncture (CLP) in male SD rats. Triiodothyronine ( T3 ) was administered intraperitoneally to correct the low T3 syndrome of septic rats. Blood was collected to examine serum NO and thyroid hormone concentration. Intestinal mucosa iNOS activity was assayed using immunochemical stain. Results Mortality rate in the prevention group was significantly lower than the septic group (Log rank = 3. 85, P 【 0.05). Serum NO concentration was significantly lower in the prevention group (F=19.6,F【0.01). The degree of inflammatory injury of intestinal mucosa was much milder in the prevention group than in the septic group (x2 = 5.303,P【0. 05). Mucosa iNOS activity was also significantly lower in the prevention group (x2 = 4. 876, P【0. 01). Conclusion Thyroid hormone protects the intestinal mucosa barrier inhibiting the expression of
文摘BACKGROUND Propofol is a short-acting,rapid-recovering anesthetic widely used in sedated colonoscopy for the early detection,diagnosis and treatment of colon diseases.However,the use of propofol alone may require high doses to achieve the induction of anesthesia in sedated colonoscopy,which has been associated with anesthesia-related adverse events(AEs),including hypoxemia,sinus bradycardia,and hypotension.Therefore,propofol co-administrated with other anesthetics has been proposed to reduce the required dose of propofol,enhance the efficacy,and improve the satisfaction of patients receiving colonoscopy under sedation.AIM To evaluate the efficacy and safety of propofol target-controlled infusion(TCI)in combination with butorphanol for sedation during colonoscopy.METHODS In this controlled clinical trial,a total of 106 patients,who were scheduled for sedated colonoscopy,were prospectively recruited and assigned into three groups to receive different doses of butorphanol before propofol TCI:Low-dose butorphanol group(5μg/kg,group B1),high-dose butorphanol group(10μg/kg,group B2),and control group(normal saline,group C).Anesthesia was achieved by propofol TCI.The primary outcome was the median effective concentration(EC50)of propofol TCI,which was measured using the up-and-down sequential method.The secondary outcomes included AEs in perianesthesia and recovery characteristics.RESULTS The EC50 of propofol for TCI was 3.03μg/mL[95%confidence interval(CI):2.83-3.23μg/mL]in group B2,3.41μg/mL(95%CI:3.20-3.62μg/mL)in group B1,and 4.05μg/mL(95%CI:3.78-4.34μg/mL)in group C.The amount of propofol necessary for anesthesia was 132 mg[interquartile range(IQR),125-144.75 mg]in group B2 and 142 mg(IQR,135-154 mg)in group B1.Furthermore,the awakening concentration was 1.1μg/mL(IQR,0.9-1.2μg/mL)in group B2 and 1.2μg/mL(IQR,1.025-1.5μg/mL)in group B1.Notably,the propofol TCI plus butorphanol groups(groups B1 and B2)had a lower incidence of anesthesia AEs,when compared to group C.Furthermore,no significant differences were observed in the rates of AEs in perianesthesia,including hypoxemia,sinus bradycardia,hypotension,nausea and vomiting,and vertigo,among group C,group B1 and group B2.CONCLUSION The combined use with butorphanol reduces the EC50 of propofol TCI for anesthesia.The decrease in propofol might contribute to the reduced anesthesia-related AEs in patients undergoing sedated colonoscopy.
文摘The channel lateral pocket or halo region of NMOSFET characterized by interface state R G current of a forward gated diode has been investigated numerically for the first time.The result of numerical analysis demonstrates that the effective surface doping concentration and the interface state density of the pocket or halo region are interface states R G current peak position dependent and amplitude dependent,respectively.It can be expressed quantitatively according to the device physics knowledge,thus,the direct characterization of the interface state density and the effective surface doping concentration of the pocket or halo becomes very easy.
基金supported by the National Natural Science Foundation of China (Nos. 31601866 and 31501844)the Heilongjiang Province Colleges and Universities Youth Innovative Training Program (Nos. UNPYSCT2017178 and 2017180)
文摘Chlorpyrifos and dimethoate are overused agricultural pesticides that can trigger trophic cascades, resulting in toxicity to both terrestrial and aquatic organisms as well as altered ecosystems. In previous studies, substantial attention has been given to the effects of pesticides on vertebrate species and, to a lesser extent, species of zooplankton. The present study was designed to show that the fission time effective concentration in ciliates is a potential aquatic detection index for environmental monitoring. The ciliate Urostyla grandis was treated with doses of chlorpyrifos and dimethoate. After exposed to the pesticides, the LC_(50)(i.e., concentration that killed 50% of the ciliate cells within 24 h) values were 0.029 mg L^(-1) for chlorpyrifos and 0.0685 mg L^(-1) for dimethoate. The fission time effective concentrations after 168 h of exposure were 0.0075–0.0093 mg L^(-1) for chlorpyrifos and 0.2640–0.2750 mg L^(-1) for dimethoate. These results show that the fission time effective concentration is lower than the LC_(50) value in ciliates, indicating that fission time effective concentration is more suitable than the LC_(50) value for environmental monitoring using ciliates. The effects of chlorpyrifos and dimethoate on ciliate cell ultrastructures included agglutination of chromatin in the macronucleus, protruded and discontinuous macronuclear and micronuclear membranes, loss of integrity of mitochondrial membranes and contents, and abscission and deformation of the adoral zone of membranelles.
基金supported by the National Natural Science Foundation of China (No.20677021)the Science Foundation of Jishou University (No.jsdxkyzz200101)
文摘This study aimed to develop original laboratory culture and sediment toxicity testing protocols for the freshwater gastropod Bellamya aeruginosa (Reeve), a new potential species for sediment toxicity testing. B. aeruginosa was successfully cultured with an effective culture system under proposed laboratory conditions. Optimal ad libitum feeding levels for larvae, juveniles, and adults were 2.0, 6.0, and 16.0 mg fish food/(snall.day), respectively. Mean survival rates of juveniles were higher than 90%, The snails could be sexed at 9 weeks of age, and their generation time is approximately 4 months. Reproduction continued all year around; the mean fecundity was 0.55 newborn/(female.day). The utility of this species for bioassays was evaluated in both 10-day and 28-day case studies with artificial sediments. The 10-day LC50 of Cu for larvae was 480 μg/g dry weight (dw), and the lowest observed effects concentration of Cu for survival and growth of larvae was 195 μg/g dw. Survival and growth are reliable indicators of acute toxicity. Larvae accumulated more Cu than adults. B. aeruginosa exhibited a higher sensitivity to Cu exposure than standard test species (Hyalella azteca and Chironomus tentans). The 28-day test of sediment toxicity with adults showed that fecundity was a robust endpoint indicator of reproductive toxicity, and the biochemical endpoints of superoxide dismutase, catalase, and glutathione could be used as sensitive biomarkers for Cu-induced oxidative damage. B. aeruginosa can be therefore recommended as a candidate for the standardization of the freshwater sediment toxicity test protocol.
基金The National Natural Science Foundation of China(No. 20337010) and the Major State Basic Research Development Program(973) of China (No.2004CB418506)
文摘The phytotoxicity of chlorobenzoic acids(CBAs) was studied and the biochemical endpoints' suitability and sensibility was evaluated. Two terrestrial plant species in the same family were exposed to different concentrations of CBAS and tested their germination according to the guideline of Organization for Economic Cooperation and Development(OECP, 1984). The results showed that CBA dose-inhibition rate of classical endpoint had the distinct linear relationship in the range of 10%—50% inhibition rate for root elongation(p<0.01), and the dose variances of CBAs had the greater influence on the inhibition rate of germination than on inhibition rate of root elongation. The CBA dose half effect concentration-inhibition rate of two antioxidant enzyme activity superoxide dismutase(SOD) and catalase (CAT) had the quadratic relationship, and CBA dose-inhibition rate of the peroxides(POD) activity had the linear relationship(p<0.05). Comparing the half effect concentration (EC_ 50) of two kinds of endpoints, the POD activity was more sensitive than classical endpoint, however, SOD and CAT activity were not sensitive in the experiment.