Emulsion of waxy crude oil is one of the common states in the subsea pipeline. At low temperatures in offshore environment, waxy crude oils with water could form the crude oil emulsion gel of oil-in-water emulsion. Th...Emulsion of waxy crude oil is one of the common states in the subsea pipeline. At low temperatures in offshore environment, waxy crude oils with water could form the crude oil emulsion gel of oil-in-water emulsion. Thus, the waxy crude oil emulsion viscoelastic behavior for deep sea transportation and restarting pipeline safety is particularly important. By means of MASIII HAAKE rheometer which is produced by German company, waxy crude oil emulsion viscoelastic behavior is explored at different volumetric water contents and different shear stresses. By analyzing the rate of change of shear rate in the initial stage, the influence rules of viscoelastic properties were summarized, with the change of volumetric water content and the applied shear stress and based on the experimental results, the law of emulsion is explained from the micro level. It is proposed that brittle fracture exists between wax crystals, and flexible fracture was found in the interaction between water droplets and wax crystals.展开更多
<span style="font-family:Verdana;">T</span><span style="font-family:Verdana;font-size:12px;">he T</span><span style="font-family:Verdana;font-size:12px;">i&l...<span style="font-family:Verdana;">T</span><span style="font-family:Verdana;font-size:12px;">he T</span><span style="font-family:Verdana;font-size:12px;">i</span><span style="font-family:Verdana;font-size:12px;">Se</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">nanosheets</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">were</span><span style="font-family:Verdana;font-size:12px;"> prepared by means of ultrasound-assisted liquid </span><span style="font-family:Verdana;font-size:12px;">phase exfoliation (LPE)</span><span style="font-family:Verdana;font-size:12px;"> and the </span><span style="font-family:Verdana;font-size:12px;">nonlinear </span><span style="font-family:Verdana;font-size:12px;">saturable absorption</span><span style="font-family:Verdana;font-size:12px;"> properties</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">were experimentally</span><span style="font-family:Verdana;font-size:12px;"> investigated. The modulation depth, saturation intensity and nonsaturable absorbance</span><span style="font-family:Verdana;font-size:12px;"> of the prepared </span><span style="font-family:Verdana;font-size:12px;">1T-TiSe</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">SA </span><span style="font-family:Verdana;font-size:12px;">were</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">1</span><span style="font-family:Verdana;font-size:12px;">5.7</span><span style="font-family:Verdana;font-size:12px;">%,</span><span style="font-family:Verdana;font-size:12px;"> 1.28 M</span><span style="font-family:Verdana;font-size:12px;">W/cm</span><sup><span style="font-family:Verdana;font-size:12px;vertical-align:super;">2</span></sup><span style="font-family:Verdana;font-size:12px;"> and 8.</span><span style="font-family:Verdana;font-size:12px;">2</span><span style="font-family:Verdana;font-size:12px;">%, </span><span style="font-family:Verdana;font-size:12px;">respectively</span><span style="font-family:Verdana;font-size:12px;">. Taking advantage of the saturable absorption properties of </span><span style="font-family:Verdana;font-size:12px;">T</span><span style="font-family:Verdana;font-size:12px;">i</span><span style="font-family:Verdana;font-size:12px;">Se</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;">-based SA, a passively Q-switched erbium-doped fiber (EDF) laser was</span><span style="font-family:Verdana;font-size:12px;"> systematically demonstrated</span><span style="font-family:Verdana;font-size:12px;">. The pulse repetition rates varied from 24.50 kHz up to 73.79 kHz with the increasing pump power. The obtained shortest pulse width was 1.31 </span><span style="font-family:Verdana;font-size:12px;">μ</span><span style="font-family:Verdana;font-size:12px;">s with pulse energy of 79.28 nJ. The </span><span style="font-family:Verdana;font-size:12px;">system presented merits of low-cost SA preparation, system compactness,</span><span style="font-family:Verdana;font-size:12px;"> superb stability and high competition.</span>展开更多
BACKGROUND: Insulin receptor (IR) expression in the substantia nigra of patients with Parkinson disease (PD) is not only significantly lower than that in the substantia nigra of normal persons of the same age, but als...BACKGROUND: Insulin receptor (IR) expression in the substantia nigra of patients with Parkinson disease (PD) is not only significantly lower than that in the substantia nigra of normal persons of the same age, but also significantly lower than that in other regions in brain of himself/herself. It suggests that the abnormal effect of insulin receptor-mediated insulin, as a neurotrophic factor, is very possibly related to the loss of dopaminergic neurons in the substantia nigra and striatum in patients with Parkinson disease.OBJECTIVE: To observe the interventional effect of insulin on 1-methyl-4-phenylpyridinium ion (MPP+)-induced apoptosis of PC12.DESIGN: Controlled observation.SETTINGS: Department of Neurology, Beijing China-Japan Friendship Hospital; Department of Neurology, Huashan Hospital Affiliated to Fudan University.MATERIALS: PC12 cells were provided by the Cell Bank, Shanghai Institute of Cell Biology, Chinese Academy of Science. MPP+, MTT, HOECHST 33258 (Invitrogen Life Technologies), reverse transcription-polymerase chain reaction (RT-PCR) reagent (Takara Shuzo Co., Ltd.), flow cytometer (Bacton Dickionson, San Jose, CA), enzyme labelling instrument (Bio-Tek, Winooski, VT) and PCR circulation instrument (Takara Shuzo Co., Ltd) were used in this study.METHODS: This study was carried out in the Department of Neurology, Huashan Hospital Affiliated to Fudan University during June 2003 to August 2004. ① Cell culture and experimental grouping: PC12 cells were cultured according to the method from Peng et al, then were randomized into 3 groups; blank control group, MPP+ group and insulin group.② Detection of relative survival rate of cells: The relative survival rate of cells at different MPP+ final concentrations (0, 50, 100, 200, 300, 1 000 μmol/L) and at different culture time (0, 4, 8, 12, 18, 24 hours) in the 300 μmol/L MPP+ group and different concentrations of insulin (0, 15, 50, 100 nmol/L) in the insulin group was detected with MTT method according to the method from Hansen et al. ③ Observation of cell apoptosis: After stained by HOECHST 33258, the apoptotic cells were observed under the fluorescence miscroscope with the method from Chen et al. ④ Dection of apoptotic rate of cells: Apoptotic rate of cells was detected with flow cytometry according to the method from Zhang et al. ⑤ The expression of tyrosine hydroxylase (TH) mRNA in PC12 cells was detected with RT-PCR methods according to the modified method from Peng et al.MAIN OUTCOME MEASURES: Comparison of relative survival rate, apoptosis rate, the expression of IR mRNA and TH mRNA and cell apoptosis.RESULTS: ① After 12-hour incubation of 100, 200, 300 and 1 000 μmol/L MPP+, the relative survival rate of PC12 cells was (72.88±2.91)%, (60.64±0.81)%, (54.56±0.76)% and (16.89±2.83)%, respectively, which was significantly lower than that of blank control group (100%, P < 0.05); After 12, 18 and 24-hour incubation, the relative survival rate of PC12 cells was (54.56±0.76)%, (42.43±0.16)% and (23.56±0.17)% respectively, which was significantly lower than that of blank control group (100%, P < 0.05); When 15, 50 and 100 nmol/L insulin was pre-added to cells, the relative survival rate was (70.10±0.16)%, (78.01±2.43)% and (83.55±1.43)%, respectively, which was significantly higher than MPP+ alone [(54.56±0.76)%, P < 0.05]. ② Appototic bodies were rarely seen in the blank control group, but densely gathered in the MPP+ group and were significantly decreased in the insulin group. ③ Apoptosis rate of PC12 cells in the MPP+ group was significantly higher than that in the blank control group [(36.56±0.89)% vs. (2.34±0.23)%, P < 0.05], and that in the 15, 50, 100 nmol/L insulin group [(30.01±0.04)%, (24.23±0.37)%, (20.01±1.01)%, respectively] was significantly lower than that in MPP+ group (P < 0.05). ④ The TH mRNA expression in PC12 cells in MPP+ group was significantly lower than that in blank control group; The expression of TH mRNA in insulin group was gradually increased in an insulin dose-dependent manner. There were no significant changes in the expression of IR mRNA under different experimental conditions.CONCLUSION: Insulin can resist MPP+-induced apoptosis of PC12 cells, lessen the damage of PC12 cells, but does not change the gene expression of target cell insulin receptor.展开更多
In this work, nitrogen-doped cobalt nanoparticles/nitrogen-doped plate-like ordered mesoporous carbons(N/Co/OMCs) were used as noble-metal free electrocatalysts with high catalytic efficiency. Compared with OMCs with ...In this work, nitrogen-doped cobalt nanoparticles/nitrogen-doped plate-like ordered mesoporous carbons(N/Co/OMCs) were used as noble-metal free electrocatalysts with high catalytic efficiency. Compared with OMCs with long channel length, due to more entrances for catalytic target accessibility and a short pathway for rapid diffusion, the utilization efficiency of cobalt nanoparticles inside the plate-like OMCs with short pore length is well improved, which can take full advantage of porous structure in electrocatalysis and increase the utilization of catalysts. The active sites in N/Co/OMCs for oxygen reduction reaction(ORR) are highly exposed to oxygen molecule, which results in a high activity for ORR. By combination of the catalytic properties of nitrogen dopant, incorporation of Co nanoparticles, and structural properties of OMCs, the N/Co/plate-like OMCs are highly active noble-metal free catalysts for ORR in alkaline solution.展开更多
Based on statistical analysis on the situation of casing damage and water injection pressure in Pubei Oilfield, it shows that the main forms of casing damage in Pubei Oilfield are deformation and dislocation. Dip angl...Based on statistical analysis on the situation of casing damage and water injection pressure in Pubei Oilfield, it shows that the main forms of casing damage in Pubei Oilfield are deformation and dislocation. Dip angle and faults have a significant impact on casing damage and casing damage is closely related to water injection pressure. Through laboratory simulating experiment and theoretical calculation, the formula of critical injection pressure giving rise to casing damage is obtained and the preventive measures are drafted.展开更多
In process of crude oil production and transportation, wax and other solid deposition issues have a significant impact on oilfield production. Solid precipitation not only reduces the production efficiency and increas...In process of crude oil production and transportation, wax and other solid deposition issues have a significant impact on oilfield production. Solid precipitation not only reduces the production efficiency and increases the cost of production. Therefore, there is a need to study the rate of paraffin wax deposition and cloud point temperature in order to guide the oil field control the paraffin wax deposition. In this paper, we use the Flory theory of polymer solution to correct the liquid activity coefficients, and regular solution theory to correct for the non ideality of the solid mixture, and we consider the impact of isoparaffin. Finally, thermodynamic model is established. The actual example calculation shows that the forecast results of this model are more accurate.展开更多
Thixotropic properties are one of the low temperature rheology behaviors of gelled waxy crudes. In order to study the thixotropic behavior of gelled waxy crudes oil under cyclic loading of linear increasing and decrea...Thixotropic properties are one of the low temperature rheology behaviors of gelled waxy crudes. In order to study the thixotropic behavior of gelled waxy crudes oil under cyclic loading of linear increasing and decreasing of shear rate, three different types of waxy crude oil were studied ex-perimentally by using MARSIII rheometer. It is found that hysteresis loop area could represent strength of thixotropic properties under that loading. With increasing of the rate of share rate sweep, the area of second hysteresis loop is much smaller than first one and began a slow decline from the third hysteresis loop. Areas of each hysteresis loops were decreased with increasing temperature, but it was different in decline rate—the lower the temperature, the greater the rate of decline. The maximum rate of decrease is the first hysteresis loop with exponential decline, and remaining hysteresis hoops approximately decrease linearly. In addition, based on the experi-mental results an empirical correlation is developed to describe the relationship of hysteresis loop area and rate of share rate sweep.展开更多
Plant cytoplasmic male sterility(CMS)is maternally inherited and often manifested as aborted pollen development,but the molecular basis of abortion remains to be identified.To facilitate an investigation of CMS in cot...Plant cytoplasmic male sterility(CMS)is maternally inherited and often manifested as aborted pollen development,but the molecular basis of abortion remains to be identified.To facilitate an investigation of CMS in cotton,the complete sequence of cotton mitochondrial(mt)genome for CMS-D2 line ZBA was determined.The mt genome was assembled as a single circular molecule with 634,036 bp in length.A total of 194 ORFs,36 protein-coding genes,six r RNAs,and 24 t RNAs were identified.Several chimeric genes encoding hypothetical proteins with transmembrane domains were identified.Among them,a previously unknown chimeric gene,orf610a,which is composed of atp1 and a 485-bp downstream sequence of unknown nature,was identified.RT-PCR and q RT-PCR validation indicated that orf610a was expressed specifically in a sterile line.Ectopic expression of orf610a in yeast resulted in excessive accumulation of reactive oxygen species and reduction in ATP content,in addition to inhibition of cellular growth.Transgenic A.thaliana overexpressing orf610a fused with a mitochondrial targeting peptide displayed partial male sterility.Interaction between ORF610a and the nuclear-encoded protein RD22 indicated an association between ORF610a and pollen abortion.Positive feedback during transcriptional regulation between nuclear regulatory factors and the mt CMS gene may account for the male sterility of ZBA.展开更多
In the adenine-induced renal failure rats, reversibility of renal failure and recovery of bone mineral density (BMD) by discontinuation of adenine-rich diet were reported: We think that the effect to bone metabolism w...In the adenine-induced renal failure rats, reversibility of renal failure and recovery of bone mineral density (BMD) by discontinuation of adenine-rich diet were reported: We think that the effect to bone metabolism with medication may be able to be evaluated as reinforcement of the BMD recovery. We have so far investigated the Chinese herbal medicine based on Hachimi-jio-gan (HJG) which are more effective than HJG alone. In this study, we investigated the effects of our Chinese herbal prescription on BMD in the adenine-treated rats compared to that of vitamin D3treatment. Young male rats were administrated 100 mg/ml adenine for 8 weeks, and they showed renal failure and bone loss. The adenine-treated rats were divided into the following 3 groups, that is, the group experienced no treatment (control), the group givenour Chinese herbal medicine (HAO), and the group given vitamin D3 (VD3) medication. It is likely that VD3 medication was less effective for increase of the femoral BMD than increase of the spinal BMD. In contrast, HAO was effective for increase of the femoral BMD. The VD3 group showed low deoxypyridinoline (Dpd: bone resorption maker) as compared to the control group.However, the HAO group showed same or slightly high Dpd. It is suggested that VD3 may increase BMD by reduction of bone resorption, while HAO may show effect on BMD by activating bone metabolism. It is indicated that HAO may become a curative medicine for bone loss because of the different target site from vitamin D3.展开更多
In recent years, the water content of oilfield production fluid is high and there is a large amount of oily sewage. In order to improve the capability of sewage treatment, usually using demulsifier for oily sewage pro...In recent years, the water content of oilfield production fluid is high and there is a large amount of oily sewage. In order to improve the capability of sewage treatment, usually using demulsifier for oily sewage processing. This article uses simulated water sample to test the treatment effect of the optimized reverse demulsifier at different oscillation time. As the increase of action time and oscillation, the average size of droplets increases and the amount of the droplets under 1 μm decreases.展开更多
Thixotropy is a great rheological behavior of waxy crudes oils and is of great importance for hydraulic characteristics and security of oil pipeline restart. In this paper, through the experiment of four waxy crudes, ...Thixotropy is a great rheological behavior of waxy crudes oils and is of great importance for hydraulic characteristics and security of oil pipeline restart. In this paper, through the experiment of four waxy crudes, three kinds of thixotropic rheology characteristics in the conditions that shear stress decays under a constant shear rate, shear stress decays after shear rate steps up and hysteresis loop of shear rate cycle changes are studied . For eight thixotropic models, experimental data are fitted in the method of least-squares and average deviation is taken as a statistical indicator to evaluate the thixotropic models. It shows that the model with the idea of Cheng that completely reversible and totally irreversible structures both exist in waxy oil products and based on Houska model can describe thixotropic behaviors of waxy crudes most well.展开更多
Recrystallization is a critical issue in ITER and future fusion devices as it strongly deteriorates the prop-erties and serving life of tungsten divertor armor.In this work,we investigated the influence of neon on the...Recrystallization is a critical issue in ITER and future fusion devices as it strongly deteriorates the prop-erties and serving life of tungsten divertor armor.In this work,we investigated the influence of neon on the recrystallization behavior of tungsten and its underlying mechanism by both experimental anal-ysis and molecular dynamics simulation.Rolled tungsten was irradiated by neon ion with energies of 10 and 100 keV and fluences of 1×10^(18)-1×10^(20)m^(−2),followed by isochronal annealing at various temperatures(1473-2073 K)for 1 h.The results indicate that 10 keV neon ion irradiation slightly in-hibits tungsten recrystallization due to the shallow depth distribution of neon(35 nm),whereas 100 keV neon ion irradiation exerts a significant retarding effect on tungsten recrystallization when neon con-centration reaches∼102 appm.Grain boundaries can hardly move with neon concentration reaching 400 appm,above which the retarding effect is very strong and varies little.The retarded recrystallization is mainly attributed to the pinning effect of neon clusters/bubbles on the grain boundary movement dur-ing annealing.Large neon clusters are found to play a predominant role in the retarding effect and the un-clustered neon atoms show a very limited effect on the grain boundary movement.By comparing the neon effects on recrystallization in this work and helium effects reported in the literature,we found that helium exhibits a relatively stronger recrystallization retarding effect than neon.This is because helium is more easily to diffuse into grain boundaries and form larger clusters due to its high diffusivity and low self-trapping energy in tungsten,which can greatly impede the migration of grain boundaries.This work provides a fundamental insight into the neon-concentration dependent recrystallization retarding effect in tungsten and the corresponding underlying atomic-level mechanisms.展开更多
文摘Emulsion of waxy crude oil is one of the common states in the subsea pipeline. At low temperatures in offshore environment, waxy crude oils with water could form the crude oil emulsion gel of oil-in-water emulsion. Thus, the waxy crude oil emulsion viscoelastic behavior for deep sea transportation and restarting pipeline safety is particularly important. By means of MASIII HAAKE rheometer which is produced by German company, waxy crude oil emulsion viscoelastic behavior is explored at different volumetric water contents and different shear stresses. By analyzing the rate of change of shear rate in the initial stage, the influence rules of viscoelastic properties were summarized, with the change of volumetric water content and the applied shear stress and based on the experimental results, the law of emulsion is explained from the micro level. It is proposed that brittle fracture exists between wax crystals, and flexible fracture was found in the interaction between water droplets and wax crystals.
文摘<span style="font-family:Verdana;">T</span><span style="font-family:Verdana;font-size:12px;">he T</span><span style="font-family:Verdana;font-size:12px;">i</span><span style="font-family:Verdana;font-size:12px;">Se</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">nanosheets</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">were</span><span style="font-family:Verdana;font-size:12px;"> prepared by means of ultrasound-assisted liquid </span><span style="font-family:Verdana;font-size:12px;">phase exfoliation (LPE)</span><span style="font-family:Verdana;font-size:12px;"> and the </span><span style="font-family:Verdana;font-size:12px;">nonlinear </span><span style="font-family:Verdana;font-size:12px;">saturable absorption</span><span style="font-family:Verdana;font-size:12px;"> properties</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">were experimentally</span><span style="font-family:Verdana;font-size:12px;"> investigated. The modulation depth, saturation intensity and nonsaturable absorbance</span><span style="font-family:Verdana;font-size:12px;"> of the prepared </span><span style="font-family:Verdana;font-size:12px;">1T-TiSe</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">SA </span><span style="font-family:Verdana;font-size:12px;">were</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">1</span><span style="font-family:Verdana;font-size:12px;">5.7</span><span style="font-family:Verdana;font-size:12px;">%,</span><span style="font-family:Verdana;font-size:12px;"> 1.28 M</span><span style="font-family:Verdana;font-size:12px;">W/cm</span><sup><span style="font-family:Verdana;font-size:12px;vertical-align:super;">2</span></sup><span style="font-family:Verdana;font-size:12px;"> and 8.</span><span style="font-family:Verdana;font-size:12px;">2</span><span style="font-family:Verdana;font-size:12px;">%, </span><span style="font-family:Verdana;font-size:12px;">respectively</span><span style="font-family:Verdana;font-size:12px;">. Taking advantage of the saturable absorption properties of </span><span style="font-family:Verdana;font-size:12px;">T</span><span style="font-family:Verdana;font-size:12px;">i</span><span style="font-family:Verdana;font-size:12px;">Se</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;">-based SA, a passively Q-switched erbium-doped fiber (EDF) laser was</span><span style="font-family:Verdana;font-size:12px;"> systematically demonstrated</span><span style="font-family:Verdana;font-size:12px;">. The pulse repetition rates varied from 24.50 kHz up to 73.79 kHz with the increasing pump power. The obtained shortest pulse width was 1.31 </span><span style="font-family:Verdana;font-size:12px;">μ</span><span style="font-family:Verdana;font-size:12px;">s with pulse energy of 79.28 nJ. The </span><span style="font-family:Verdana;font-size:12px;">system presented merits of low-cost SA preparation, system compactness,</span><span style="font-family:Verdana;font-size:12px;"> superb stability and high competition.</span>
文摘BACKGROUND: Insulin receptor (IR) expression in the substantia nigra of patients with Parkinson disease (PD) is not only significantly lower than that in the substantia nigra of normal persons of the same age, but also significantly lower than that in other regions in brain of himself/herself. It suggests that the abnormal effect of insulin receptor-mediated insulin, as a neurotrophic factor, is very possibly related to the loss of dopaminergic neurons in the substantia nigra and striatum in patients with Parkinson disease.OBJECTIVE: To observe the interventional effect of insulin on 1-methyl-4-phenylpyridinium ion (MPP+)-induced apoptosis of PC12.DESIGN: Controlled observation.SETTINGS: Department of Neurology, Beijing China-Japan Friendship Hospital; Department of Neurology, Huashan Hospital Affiliated to Fudan University.MATERIALS: PC12 cells were provided by the Cell Bank, Shanghai Institute of Cell Biology, Chinese Academy of Science. MPP+, MTT, HOECHST 33258 (Invitrogen Life Technologies), reverse transcription-polymerase chain reaction (RT-PCR) reagent (Takara Shuzo Co., Ltd.), flow cytometer (Bacton Dickionson, San Jose, CA), enzyme labelling instrument (Bio-Tek, Winooski, VT) and PCR circulation instrument (Takara Shuzo Co., Ltd) were used in this study.METHODS: This study was carried out in the Department of Neurology, Huashan Hospital Affiliated to Fudan University during June 2003 to August 2004. ① Cell culture and experimental grouping: PC12 cells were cultured according to the method from Peng et al, then were randomized into 3 groups; blank control group, MPP+ group and insulin group.② Detection of relative survival rate of cells: The relative survival rate of cells at different MPP+ final concentrations (0, 50, 100, 200, 300, 1 000 μmol/L) and at different culture time (0, 4, 8, 12, 18, 24 hours) in the 300 μmol/L MPP+ group and different concentrations of insulin (0, 15, 50, 100 nmol/L) in the insulin group was detected with MTT method according to the method from Hansen et al. ③ Observation of cell apoptosis: After stained by HOECHST 33258, the apoptotic cells were observed under the fluorescence miscroscope with the method from Chen et al. ④ Dection of apoptotic rate of cells: Apoptotic rate of cells was detected with flow cytometry according to the method from Zhang et al. ⑤ The expression of tyrosine hydroxylase (TH) mRNA in PC12 cells was detected with RT-PCR methods according to the modified method from Peng et al.MAIN OUTCOME MEASURES: Comparison of relative survival rate, apoptosis rate, the expression of IR mRNA and TH mRNA and cell apoptosis.RESULTS: ① After 12-hour incubation of 100, 200, 300 and 1 000 μmol/L MPP+, the relative survival rate of PC12 cells was (72.88±2.91)%, (60.64±0.81)%, (54.56±0.76)% and (16.89±2.83)%, respectively, which was significantly lower than that of blank control group (100%, P < 0.05); After 12, 18 and 24-hour incubation, the relative survival rate of PC12 cells was (54.56±0.76)%, (42.43±0.16)% and (23.56±0.17)% respectively, which was significantly lower than that of blank control group (100%, P < 0.05); When 15, 50 and 100 nmol/L insulin was pre-added to cells, the relative survival rate was (70.10±0.16)%, (78.01±2.43)% and (83.55±1.43)%, respectively, which was significantly higher than MPP+ alone [(54.56±0.76)%, P < 0.05]. ② Appototic bodies were rarely seen in the blank control group, but densely gathered in the MPP+ group and were significantly decreased in the insulin group. ③ Apoptosis rate of PC12 cells in the MPP+ group was significantly higher than that in the blank control group [(36.56±0.89)% vs. (2.34±0.23)%, P < 0.05], and that in the 15, 50, 100 nmol/L insulin group [(30.01±0.04)%, (24.23±0.37)%, (20.01±1.01)%, respectively] was significantly lower than that in MPP+ group (P < 0.05). ④ The TH mRNA expression in PC12 cells in MPP+ group was significantly lower than that in blank control group; The expression of TH mRNA in insulin group was gradually increased in an insulin dose-dependent manner. There were no significant changes in the expression of IR mRNA under different experimental conditions.CONCLUSION: Insulin can resist MPP+-induced apoptosis of PC12 cells, lessen the damage of PC12 cells, but does not change the gene expression of target cell insulin receptor.
基金financial support from the National Natural Science Foundation of China(21405011)the Science and Technology Development Planning of Jilin Province(20150520014JH)
文摘In this work, nitrogen-doped cobalt nanoparticles/nitrogen-doped plate-like ordered mesoporous carbons(N/Co/OMCs) were used as noble-metal free electrocatalysts with high catalytic efficiency. Compared with OMCs with long channel length, due to more entrances for catalytic target accessibility and a short pathway for rapid diffusion, the utilization efficiency of cobalt nanoparticles inside the plate-like OMCs with short pore length is well improved, which can take full advantage of porous structure in electrocatalysis and increase the utilization of catalysts. The active sites in N/Co/OMCs for oxygen reduction reaction(ORR) are highly exposed to oxygen molecule, which results in a high activity for ORR. By combination of the catalytic properties of nitrogen dopant, incorporation of Co nanoparticles, and structural properties of OMCs, the N/Co/plate-like OMCs are highly active noble-metal free catalysts for ORR in alkaline solution.
文摘Based on statistical analysis on the situation of casing damage and water injection pressure in Pubei Oilfield, it shows that the main forms of casing damage in Pubei Oilfield are deformation and dislocation. Dip angle and faults have a significant impact on casing damage and casing damage is closely related to water injection pressure. Through laboratory simulating experiment and theoretical calculation, the formula of critical injection pressure giving rise to casing damage is obtained and the preventive measures are drafted.
文摘In process of crude oil production and transportation, wax and other solid deposition issues have a significant impact on oilfield production. Solid precipitation not only reduces the production efficiency and increases the cost of production. Therefore, there is a need to study the rate of paraffin wax deposition and cloud point temperature in order to guide the oil field control the paraffin wax deposition. In this paper, we use the Flory theory of polymer solution to correct the liquid activity coefficients, and regular solution theory to correct for the non ideality of the solid mixture, and we consider the impact of isoparaffin. Finally, thermodynamic model is established. The actual example calculation shows that the forecast results of this model are more accurate.
文摘Thixotropic properties are one of the low temperature rheology behaviors of gelled waxy crudes. In order to study the thixotropic behavior of gelled waxy crudes oil under cyclic loading of linear increasing and decreasing of shear rate, three different types of waxy crude oil were studied ex-perimentally by using MARSIII rheometer. It is found that hysteresis loop area could represent strength of thixotropic properties under that loading. With increasing of the rate of share rate sweep, the area of second hysteresis loop is much smaller than first one and began a slow decline from the third hysteresis loop. Areas of each hysteresis loops were decreased with increasing temperature, but it was different in decline rate—the lower the temperature, the greater the rate of decline. The maximum rate of decrease is the first hysteresis loop with exponential decline, and remaining hysteresis hoops approximately decrease linearly. In addition, based on the experi-mental results an empirical correlation is developed to describe the relationship of hysteresis loop area and rate of share rate sweep.
基金supported by funds from the National Natural Science Foundation of China(31871679)the Tianshan Youth Program(2018Q010)the Central Public-interest Scientific Institution Basal Research Fund(1610162021015)。
文摘Plant cytoplasmic male sterility(CMS)is maternally inherited and often manifested as aborted pollen development,but the molecular basis of abortion remains to be identified.To facilitate an investigation of CMS in cotton,the complete sequence of cotton mitochondrial(mt)genome for CMS-D2 line ZBA was determined.The mt genome was assembled as a single circular molecule with 634,036 bp in length.A total of 194 ORFs,36 protein-coding genes,six r RNAs,and 24 t RNAs were identified.Several chimeric genes encoding hypothetical proteins with transmembrane domains were identified.Among them,a previously unknown chimeric gene,orf610a,which is composed of atp1 and a 485-bp downstream sequence of unknown nature,was identified.RT-PCR and q RT-PCR validation indicated that orf610a was expressed specifically in a sterile line.Ectopic expression of orf610a in yeast resulted in excessive accumulation of reactive oxygen species and reduction in ATP content,in addition to inhibition of cellular growth.Transgenic A.thaliana overexpressing orf610a fused with a mitochondrial targeting peptide displayed partial male sterility.Interaction between ORF610a and the nuclear-encoded protein RD22 indicated an association between ORF610a and pollen abortion.Positive feedback during transcriptional regulation between nuclear regulatory factors and the mt CMS gene may account for the male sterility of ZBA.
文摘In the adenine-induced renal failure rats, reversibility of renal failure and recovery of bone mineral density (BMD) by discontinuation of adenine-rich diet were reported: We think that the effect to bone metabolism with medication may be able to be evaluated as reinforcement of the BMD recovery. We have so far investigated the Chinese herbal medicine based on Hachimi-jio-gan (HJG) which are more effective than HJG alone. In this study, we investigated the effects of our Chinese herbal prescription on BMD in the adenine-treated rats compared to that of vitamin D3treatment. Young male rats were administrated 100 mg/ml adenine for 8 weeks, and they showed renal failure and bone loss. The adenine-treated rats were divided into the following 3 groups, that is, the group experienced no treatment (control), the group givenour Chinese herbal medicine (HAO), and the group given vitamin D3 (VD3) medication. It is likely that VD3 medication was less effective for increase of the femoral BMD than increase of the spinal BMD. In contrast, HAO was effective for increase of the femoral BMD. The VD3 group showed low deoxypyridinoline (Dpd: bone resorption maker) as compared to the control group.However, the HAO group showed same or slightly high Dpd. It is suggested that VD3 may increase BMD by reduction of bone resorption, while HAO may show effect on BMD by activating bone metabolism. It is indicated that HAO may become a curative medicine for bone loss because of the different target site from vitamin D3.
文摘In recent years, the water content of oilfield production fluid is high and there is a large amount of oily sewage. In order to improve the capability of sewage treatment, usually using demulsifier for oily sewage processing. This article uses simulated water sample to test the treatment effect of the optimized reverse demulsifier at different oscillation time. As the increase of action time and oscillation, the average size of droplets increases and the amount of the droplets under 1 μm decreases.
文摘Thixotropy is a great rheological behavior of waxy crudes oils and is of great importance for hydraulic characteristics and security of oil pipeline restart. In this paper, through the experiment of four waxy crudes, three kinds of thixotropic rheology characteristics in the conditions that shear stress decays under a constant shear rate, shear stress decays after shear rate steps up and hysteresis loop of shear rate cycle changes are studied . For eight thixotropic models, experimental data are fitted in the method of least-squares and average deviation is taken as a statistical indicator to evaluate the thixotropic models. It shows that the model with the idea of Cheng that completely reversible and totally irreversible structures both exist in waxy oil products and based on Houska model can describe thixotropic behaviors of waxy crudes most well.
基金This work was financially supported by the National MCF En-ergy R&D Program(No.2019YFE03110100)the National Natural Science Foundation of China(Nos.12075020 and 12105304)the Academic Excellence Foundation of BUAA for PhD Students.Dr.Yue Yuan acknowledges the support from the Fundamental Re-search Funds for the Central Universities.
文摘Recrystallization is a critical issue in ITER and future fusion devices as it strongly deteriorates the prop-erties and serving life of tungsten divertor armor.In this work,we investigated the influence of neon on the recrystallization behavior of tungsten and its underlying mechanism by both experimental anal-ysis and molecular dynamics simulation.Rolled tungsten was irradiated by neon ion with energies of 10 and 100 keV and fluences of 1×10^(18)-1×10^(20)m^(−2),followed by isochronal annealing at various temperatures(1473-2073 K)for 1 h.The results indicate that 10 keV neon ion irradiation slightly in-hibits tungsten recrystallization due to the shallow depth distribution of neon(35 nm),whereas 100 keV neon ion irradiation exerts a significant retarding effect on tungsten recrystallization when neon con-centration reaches∼102 appm.Grain boundaries can hardly move with neon concentration reaching 400 appm,above which the retarding effect is very strong and varies little.The retarded recrystallization is mainly attributed to the pinning effect of neon clusters/bubbles on the grain boundary movement dur-ing annealing.Large neon clusters are found to play a predominant role in the retarding effect and the un-clustered neon atoms show a very limited effect on the grain boundary movement.By comparing the neon effects on recrystallization in this work and helium effects reported in the literature,we found that helium exhibits a relatively stronger recrystallization retarding effect than neon.This is because helium is more easily to diffuse into grain boundaries and form larger clusters due to its high diffusivity and low self-trapping energy in tungsten,which can greatly impede the migration of grain boundaries.This work provides a fundamental insight into the neon-concentration dependent recrystallization retarding effect in tungsten and the corresponding underlying atomic-level mechanisms.
