AIM: To assess the mechanisms of protective action by different mild irritants through maintenance of gastric mucosal integrity and modulation of mucosal nitric oxide (NO) in experimental gastritis rats.METHODS: Etche...AIM: To assess the mechanisms of protective action by different mild irritants through maintenance of gastric mucosal integrity and modulation of mucosal nitric oxide (NO) in experimental gastritis rats.METHODS: Etcher 200 mL/L ethanol, 50 g/L NaG or 0.3 mol/L HCl was pretreated to normal or 800 mL/L ethanol-induced acute gastritis Sprague-Dawley rats before a subsequent challenge with 500 mL/L ethanol. Both macroscopic lesion areas and histological damage scores were determined in the gastric mucosa of each group of animals. Besides,gastric mucosal activities of NO synthase isoforms and of superoxide dismutase, along with mucosal level of leukotriene (LT)C4 were measured.RESULTS: Macroscopic mucosal damages were protected by 200 mL/L ethanol and 50 g/L NaCI in gastritis rats.However, although 200 mL/L ethanol could protect the surface layers of mucosal cells in normal animals (protection attenuated by NG-nitro-L-arginine methyl ester), no cytoprotection against deeper histological damages was found in gastritis rats. Besides, inducible NO synthase activity was increased in the mucosa of gastritis animals and unaltered by mild irritants. Nevertheless, the elevation in mucosal LTC4 level following 500 mL/L ethanol administration and under gastritis condition was significantly reduced by pretreatment of all three mild irritants in both normal and gastritis animals.CONCLUSION: These findings suggest that the aggravated 500 mL/L ethanol-evoked mucosal damages under gastritis condition could be due to increased inducible NO and LTC4 production in the gastric mucosa. Only 200 mL/L ethanol is truly 'cytoprotective' at the surface glandular level of nongastritis mucosa. Furthermore, the macroscopic protection of the three mild irritants involves reduction of LTC4 level in both normal and gastritis mucosa, implicating preservation of the vasculature.展开更多
The growing attention on urban tourism was very widespread. There are two angles to study urban tourism: supply-side and demand-side. And the supply-side of the tourism remains very important. The RBD (Recreation Busi...The growing attention on urban tourism was very widespread. There are two angles to study urban tourism: supply-side and demand-side. And the supply-side of the tourism remains very important. The RBD (Recreation Business District) is a useful framework to understand the components of urban tourism and how they fit together. The paper begins with a review on the RBD and the spatial structure of tourism in urban areas and then attempts to develop a more general understanding of the spatial structure evolution of RBDs in a tourist-historic city-Suzhou. The spatial structures and functions of the RBDs in Suzhou are examined, based on field observations, interviews with city officials and industry leaders, and a review of available documents. The urban tourism of Suzhou has developed in a range of contexts, that various types of RBDs have emerged as a result of different urban development strategies. The spatial structure has evolved from the past "Single-cored Structure" to "Double-cored Structure" at present, and then to "Chain Structure" in the future. The spatial form and evolution of RBD in Suzhou are closely relative with its urban spatial expansion. Urban area dispersal is the prerequisite of the emergence of the RBD. Planning and constructing the RBD becomes a new impetus to urban growth or renewal. Finally, a number of strategies for planning and developing the RBD in Suzhou are suggested. The different RBDs should adopt different strategies. Intensification can be the possible strategy for the RBDs in the ancient city. Accreting with the urban theme park or engrafting on the Jinji Lake is suggested respectively for the RBD in the Suzhou New District and the Suzhou Industrial Park.展开更多
This experiment was an attempt to use the soybean residue derived from the production of 'soy milk'. The residue contains about 18% protein, 70% caf bohydrates and 7.5% lipid as fish feed for reafing common ca...This experiment was an attempt to use the soybean residue derived from the production of 'soy milk'. The residue contains about 18% protein, 70% caf bohydrates and 7.5% lipid as fish feed for reafing common carp, Cyrinus carpto. There were 4 types of diets: (1)soybean residue, (2 ) soybean residue digested with Papain, (3) soybean residue (64%)mixed with beef liver (34%) and (4) same mixture as (3) but digested with Papain. The results indicate that the percentage increase in weight and length of fish feeding with beef liver supplemented diets was higher than those feeding with soybean residue alone. This was possibly due to the fact that beef liver was able to supplement the nutrient deficiency in soybean. The two types of feeds (2 and 4) digested with Papain also yielded significantly better fish growth in terms of weight and length gains, than their counterparts without digestion. Furthermore, the water turbidity of the tanks added with digested feeds was significantly less, as papain was able to hyrolyse the protein substrates suspended in the water, and thus lowered the turbidity展开更多
Task-based language teaching can be regarded as one particular development within the broader “communicative approach”. This article outlines the principles that underlie task-based language teaching and gives examp...Task-based language teaching can be regarded as one particular development within the broader “communicative approach”. This article outlines the principles that underlie task-based language teaching and gives examples of classroom activities within the approach. First it discusses what is meant by the term “task”. It attempts to illuminate the notion of “task” by presenting a continuum from “focusing on form” to “focusing on meaning”. This continuum is described and explored in more detail in the following section, which provides a range of examples from different parts of it. The article then outlines a way of looking at tasks in terms of how they contribute to the linguistic, cognitive and personality, development of the students. Finally the main aims and benefits of task-based learning are summarised by means of a mnemonic based on the word “task” itself.展开更多
Responses of Sesbania rostrata and S. cannabina to Pb, Zn, Cu and Cd toxicities were assessed by a seed-suspending seedbed(SSS) approach. The results showed that the SSS approach was suitable for testing the tolerance...Responses of Sesbania rostrata and S. cannabina to Pb, Zn, Cu and Cd toxicities were assessed by a seed-suspending seedbed(SSS) approach. The results showed that the SSS approach was suitable for testing the tolerance of a plant to the stress of toxic metals. The endpoints include seed germination success, straightened radicle and hypocotyl of the seedlings from the seeds. The measurements could be done easily and accurately. It was found that the elongation of radicle was the most sensitive indicator to the stress of heavy metals among the endpoints. When exposure to lower or medium concentrations of Pb, Zn, and Cd, the development of the lateral roots were favorable. Species of S. rostrata was more tolerant than S. cannabina to the heavy metals, especially to Zn and Cd. The ED 50 of Pb, Zn, Cu and Cd were 32.90, 5.32, 4.40 and 12.00 μg/ml for S. rostrata, respectively, and they were 30.11, 2.87, 4.05 and 4.94 μg/ml respectively for S. cannabina.展开更多
An aqueous acidic polysaccharide, named rhamnogalacturonan (designated as TTP-D2) was isolated from Tribulus terrestris L by means of DEAE-cellulose chromatography and gel filtration. The molecular mass of TTP-D2 wa...An aqueous acidic polysaccharide, named rhamnogalacturonan (designated as TTP-D2) was isolated from Tribulus terrestris L by means of DEAE-cellulose chromatography and gel filtration. The molecular mass of TTP-D2 was estimated to be 26 KDa by gel filtration. TTP-D2 is composed of galacturonic acid, rhamnose, arabinose, galactose, fucose, mannose, xylose and glucose in a ratio of 71.4 : 13.5 : 5.6 : 4.9 : 3.1 : 1.9 : 1.9 : 1.0. The main chain structure of TTP-D2 was elucidated as an acidic hetero-polysaccharide with the connection of a-(1-4) galacturonic acid with a-(1-3) rhamnose by GC analysis of partially hydrolyzed products and the determination of 1H, 13C-NMR spectra.展开更多
This work describes the simultaneous deter- mination of catechins and caffeine in green, black tealeaves and canned tea-drink using micellar electrokinetic chromatography. The catechins analyzed include (+)-catechin, ...This work describes the simultaneous deter- mination of catechins and caffeine in green, black tealeaves and canned tea-drink using micellar electrokinetic chromatography. The catechins analyzed include (+)-catechin, (-)- epicatechin, (-)-epigallocatechin, (-)-epicatechin gallate and (-)-epigallocatechin gallate. Using UV absorption method at 280 nm, the limits of detections of catechins and caffeine are 10-6 mol/L, which is suitable for the real sample determination. Using this analytical method, the extraction of these compounds from the tealeaves with hot water is compared under different temperatures. The effects of temperature on the amount of catechins and caffeine extracted are evident, showing that (-)-epigallocatechin gallate is the most easiest to be extracted at 100℃. The stability of catechins and caffeine in stocking solution of tea-drink at 4℃ is also compared on five consecutive days. The contents of catechins and caffeine in green and black teas are discussed and the difference of the content between different tealeaves can provide a reference for the assessment of tea quality.展开更多
Vitellogenin (Vtg) is the precursor of yolk protein. Its expression and secretion are estrogen-regulated and are crucial for oocyte maturation. An in vitro xenoestro- gen screening model was established by measuring V...Vitellogenin (Vtg) is the precursor of yolk protein. Its expression and secretion are estrogen-regulated and are crucial for oocyte maturation. An in vitro xenoestro- gen screening model was established by measuring Vtg in- duction in cultured primary hepatocytes from crucian carp. Vtg production was detected by biotin-avidin sandwich ELISA method while Vtg and cytochrome P4501A1 (CYP1A1) mRNA induction were measured by semi- quan- titative PCR-primer dropping technique. Vtg and Vtg mRNA were dose-dependently induced by diethylstilbestrol (DES, 0.2—200 ng/mL) in hepatocytes of crucian carp. Co-treatment of the DES-induced hepatocytes with either 2,3,7,8-TCDD (TCDD, 0.1—4 pg/mL) or benzo[a]pyrene (B[a]P, 5—1000 ng/mL) resulted in a reduction of Vtg pro- duction and an increment of CYP1A1 mRNA expression both in a dose dependent manner, indicating the anti-estro- genic effects of the compounds. However, at lower tested concentrations, TCDD (0.1, 0.2 pg/mL), B[a]P (5 ng/mL) seemed to have a potentiating effect on Vtg expression and secretion, although by their own these compounds had no observable estrogenic effect on Vtg induction. Tamoxifen (a selective estrogen receptor modulators, 1 nmol/L—1 μmol/L), and β-naphtho-flavone (β-NF, an aryl hydrocarbon receptor inducing compounds, 2.5—1000 ng/mL) also were employed to study the possible interactions in DES-induced Vtg ex- pression. In co-treatment of the DES-induced hepatocytes with β-NF or tamoxifen, the decrease in Vtg production did parallel induction of CYP1A1 for β-NF, but tamoxifen inhib- ited Vtg induction did not parallel induced CYP1A1 expres- sion in all test concentrations. On the contrary, it was found that in co-treatment of the TCDD-induced hepatocytes with DES, TCDD induced CYP1A1 mRNA production was inhib- ited by DES also. These results implicated a possible cross talk between estrogen receptor- and aryl hydrocarbon re- ceptor-mediated pathways in the hepatocytes.展开更多
Recent developments in studies of directed transport processes in interacting particle systems are retrospected. Due to the interactions among elements, the directed transport process exhibits complicated and novel co...Recent developments in studies of directed transport processes in interacting particle systems are retrospected. Due to the interactions among elements, the directed transport process exhibits complicated and novel cooperative dynamics. We considered various possibilities in achieving ratchet motion by breaking different symmetries of many-body systems. It is shown that the directional transport can even be induced by breaking the coupling symmetry and the spatiotemporal symmetries.展开更多
The aim of this paper is to develop a fast numerical method for two-dimensional boundary integral equations of the first kind with logarithm kernels when the boundary of the domain is smooth and closed. In this case, ...The aim of this paper is to develop a fast numerical method for two-dimensional boundary integral equations of the first kind with logarithm kernels when the boundary of the domain is smooth and closed. In this case, the use of the conventional boundary element methods gives linear systems with dense matrix. In this paper, we demonstrate that the dense matrix can be replaced by a sparse one if appropriate graded meshes are used in the quadrature rules. It will be demonstrated that this technique can increase the numerical efficiency significantly.展开更多
A novel approach is presented for measuring the phase synchronization (frequency-locking) of coupled nonidentical oscillators, which can characterize frequency-locking for chaotic systems without well-defined phase b...A novel approach is presented for measuring the phase synchronization (frequency-locking) of coupled nonidentical oscillators, which can characterize frequency-locking for chaotic systems without well-defined phase by measuring the mean frequency. Numerical simulations confirm the existence of frequency-locking. The relations between the mean frequency and the coupling strength and the frequency mismatch are given. For the coupled hyperchaotic systems, the frequency-locking can be better characterized by more than one mean frequency curves.展开更多
Pot-grown tomato plants (Lycopersicon esculentum Mill. cv. Maofen) was used to study the effects of three shading levels (0, 75% and 40%) for 8 days on dry matter partitioning, contents of nitrogen (N), phosphorus (P)...Pot-grown tomato plants (Lycopersicon esculentum Mill. cv. Maofen) was used to study the effects of three shading levels (0, 75% and 40%) for 8 days on dry matter partitioning, contents of nitrogen (N), phosphorus (P) and potassium (K) in leaves arid yield at three growth stages (early flowering (EF), peak flowering (PF) and later flowering (LF)). Shading reduced the dry weight of root and stem tissues at the EF and PF stages, but the 40% shading increased root dry weight and stem dry weight by 43.2% and 21.6%, respectively, at the LF stage. The influence of shading on the dry weight of leaves was very small at most growth stages. Shading had no effects on total leaf N, P and K contents at the EF and PF stages, showing that N, P and K absorption were regulated by the carbon assimilation at these two stages. The leaf N, P and K contents of 40% shaded plants at the LF stage were significantly increased. There were no obvious differences in leaf N and K contents between 75% and 40% shading treatments, but significant difference in leaf P contents was found between them at the LF stage. Shading significantly enhanced the fruit yield of 40% shaded tomato plants at the LF stage, but failed to affect the fruit yield of shaded plants at the EF stage. These showed that tomato could grow well and a better yield could be obtained if some moderate shading (i.e., 40% shading) was applied at the LF stage at summer midday.展开更多
Introduced the characteristics of series communicat io n I 2C bus and basic communication protocol, and introduced the application of the bus I 2C according to the image sensor OV7610.The computer correspondence s tyl...Introduced the characteristics of series communicat io n I 2C bus and basic communication protocol, and introduced the application of the bus I 2C according to the image sensor OV7610.The computer correspondence s tyle can be divided the parallel correspondence and the series correspondence. T he rate of series correspondence is rapid, and the property of real time is exce llent. Because the number of ports which it takes is great, it is not proper to miniaturize. Whereas the rate of series correspondence is low, but when the corr espondence of data is not great, it is simpleconvenient and agile to dispose t he circuit. Commonly series correspondence divide synchronization correspondence and asynchronies correspondence. The standard of interface RC232 is series asyn chronies correspondence. Recently the standard of bus I 2C is adopted widely in the micro-electronics correspondence realm, it is a special form of synchr onization correspondence. I 2C bus is a two-cabledouble-direction series co rrespondence bus. The address of the machine is set in hardware, and software pe rform the search of the address instead of hardware. So it reduce the number of the corresponding cable, moreover it predigest the design of the hardware. It resolve many interface problems in design of numeric circuit. More and more se miconductor manufacturer accept the standard. Its characteristics can be listed as followed. In text, the image sensor OV7610 is introduced as the example the bus I 2C appl ication.展开更多
Concentrations of C-reactive protein (CRP) in the serum of 14 patients suffering from Lyme diseasc were measured. 86% of these patients were found to have abnormally high concentrations of serum CRP (range 14-158 mg/L...Concentrations of C-reactive protein (CRP) in the serum of 14 patients suffering from Lyme diseasc were measured. 86% of these patients were found to have abnormally high concentrations of serum CRP (range 14-158 mg/L). The CRP concentration of a 60-yearold patient abated from 29 mg/L to 13 mg/L after treatrnent. Results suggest that serum CRP concentration can provide a valuable and accurate means for the clinical diagnosis and monitoring of Lyme disease展开更多
Let X = {Xt,t >=0} be a d-dimensional (d>= 2) standard Brownian motion with drift c started at a fixed x, and BR = {x E Rd: |x| < R}, the ball centered at 0 with radius R. Consider the distributions of TR(t) ...Let X = {Xt,t >=0} be a d-dimensional (d>= 2) standard Brownian motion with drift c started at a fixed x, and BR = {x E Rd: |x| < R}, the ball centered at 0 with radius R. Consider the distributions of TR(t) and TR(∞), where TR(t) denotes the time spent by X in BR up to time t and TR(∞) the total time of X spent in BR. Explicit formulas for the Laplace transform of TR(∞) and the double Laplace transform of TR(t) are obtained.展开更多
文摘AIM: To assess the mechanisms of protective action by different mild irritants through maintenance of gastric mucosal integrity and modulation of mucosal nitric oxide (NO) in experimental gastritis rats.METHODS: Etcher 200 mL/L ethanol, 50 g/L NaG or 0.3 mol/L HCl was pretreated to normal or 800 mL/L ethanol-induced acute gastritis Sprague-Dawley rats before a subsequent challenge with 500 mL/L ethanol. Both macroscopic lesion areas and histological damage scores were determined in the gastric mucosa of each group of animals. Besides,gastric mucosal activities of NO synthase isoforms and of superoxide dismutase, along with mucosal level of leukotriene (LT)C4 were measured.RESULTS: Macroscopic mucosal damages were protected by 200 mL/L ethanol and 50 g/L NaCI in gastritis rats.However, although 200 mL/L ethanol could protect the surface layers of mucosal cells in normal animals (protection attenuated by NG-nitro-L-arginine methyl ester), no cytoprotection against deeper histological damages was found in gastritis rats. Besides, inducible NO synthase activity was increased in the mucosa of gastritis animals and unaltered by mild irritants. Nevertheless, the elevation in mucosal LTC4 level following 500 mL/L ethanol administration and under gastritis condition was significantly reduced by pretreatment of all three mild irritants in both normal and gastritis animals.CONCLUSION: These findings suggest that the aggravated 500 mL/L ethanol-evoked mucosal damages under gastritis condition could be due to increased inducible NO and LTC4 production in the gastric mucosa. Only 200 mL/L ethanol is truly 'cytoprotective' at the surface glandular level of nongastritis mucosa. Furthermore, the macroscopic protection of the three mild irritants involves reduction of LTC4 level in both normal and gastritis mucosa, implicating preservation of the vasculature.
文摘The growing attention on urban tourism was very widespread. There are two angles to study urban tourism: supply-side and demand-side. And the supply-side of the tourism remains very important. The RBD (Recreation Business District) is a useful framework to understand the components of urban tourism and how they fit together. The paper begins with a review on the RBD and the spatial structure of tourism in urban areas and then attempts to develop a more general understanding of the spatial structure evolution of RBDs in a tourist-historic city-Suzhou. The spatial structures and functions of the RBDs in Suzhou are examined, based on field observations, interviews with city officials and industry leaders, and a review of available documents. The urban tourism of Suzhou has developed in a range of contexts, that various types of RBDs have emerged as a result of different urban development strategies. The spatial structure has evolved from the past "Single-cored Structure" to "Double-cored Structure" at present, and then to "Chain Structure" in the future. The spatial form and evolution of RBD in Suzhou are closely relative with its urban spatial expansion. Urban area dispersal is the prerequisite of the emergence of the RBD. Planning and constructing the RBD becomes a new impetus to urban growth or renewal. Finally, a number of strategies for planning and developing the RBD in Suzhou are suggested. The different RBDs should adopt different strategies. Intensification can be the possible strategy for the RBDs in the ancient city. Accreting with the urban theme park or engrafting on the Jinji Lake is suggested respectively for the RBD in the Suzhou New District and the Suzhou Industrial Park.
文摘This experiment was an attempt to use the soybean residue derived from the production of 'soy milk'. The residue contains about 18% protein, 70% caf bohydrates and 7.5% lipid as fish feed for reafing common carp, Cyrinus carpto. There were 4 types of diets: (1)soybean residue, (2 ) soybean residue digested with Papain, (3) soybean residue (64%)mixed with beef liver (34%) and (4) same mixture as (3) but digested with Papain. The results indicate that the percentage increase in weight and length of fish feeding with beef liver supplemented diets was higher than those feeding with soybean residue alone. This was possibly due to the fact that beef liver was able to supplement the nutrient deficiency in soybean. The two types of feeds (2 and 4) digested with Papain also yielded significantly better fish growth in terms of weight and length gains, than their counterparts without digestion. Furthermore, the water turbidity of the tanks added with digested feeds was significantly less, as papain was able to hyrolyse the protein substrates suspended in the water, and thus lowered the turbidity
文摘Task-based language teaching can be regarded as one particular development within the broader “communicative approach”. This article outlines the principles that underlie task-based language teaching and gives examples of classroom activities within the approach. First it discusses what is meant by the term “task”. It attempts to illuminate the notion of “task” by presenting a continuum from “focusing on form” to “focusing on meaning”. This continuum is described and explored in more detail in the following section, which provides a range of examples from different parts of it. The article then outlines a way of looking at tasks in terms of how they contribute to the linguistic, cognitive and personality, development of the students. Finally the main aims and benefits of task-based learning are summarised by means of a mnemonic based on the word “task” itself.
文摘Responses of Sesbania rostrata and S. cannabina to Pb, Zn, Cu and Cd toxicities were assessed by a seed-suspending seedbed(SSS) approach. The results showed that the SSS approach was suitable for testing the tolerance of a plant to the stress of toxic metals. The endpoints include seed germination success, straightened radicle and hypocotyl of the seedlings from the seeds. The measurements could be done easily and accurately. It was found that the elongation of radicle was the most sensitive indicator to the stress of heavy metals among the endpoints. When exposure to lower or medium concentrations of Pb, Zn, and Cd, the development of the lateral roots were favorable. Species of S. rostrata was more tolerant than S. cannabina to the heavy metals, especially to Zn and Cd. The ED 50 of Pb, Zn, Cu and Cd were 32.90, 5.32, 4.40 and 12.00 μg/ml for S. rostrata, respectively, and they were 30.11, 2.87, 4.05 and 4.94 μg/ml respectively for S. cannabina.
文摘An aqueous acidic polysaccharide, named rhamnogalacturonan (designated as TTP-D2) was isolated from Tribulus terrestris L by means of DEAE-cellulose chromatography and gel filtration. The molecular mass of TTP-D2 was estimated to be 26 KDa by gel filtration. TTP-D2 is composed of galacturonic acid, rhamnose, arabinose, galactose, fucose, mannose, xylose and glucose in a ratio of 71.4 : 13.5 : 5.6 : 4.9 : 3.1 : 1.9 : 1.9 : 1.0. The main chain structure of TTP-D2 was elucidated as an acidic hetero-polysaccharide with the connection of a-(1-4) galacturonic acid with a-(1-3) rhamnose by GC analysis of partially hydrolyzed products and the determination of 1H, 13C-NMR spectra.
基金supported by the National Science Fund for Distinguished Young Scholars of China(Grant No.20125514)the National Natural Science Foundation of China(Grant Nos.50273046 and 20275043).
文摘This work describes the simultaneous deter- mination of catechins and caffeine in green, black tealeaves and canned tea-drink using micellar electrokinetic chromatography. The catechins analyzed include (+)-catechin, (-)- epicatechin, (-)-epigallocatechin, (-)-epicatechin gallate and (-)-epigallocatechin gallate. Using UV absorption method at 280 nm, the limits of detections of catechins and caffeine are 10-6 mol/L, which is suitable for the real sample determination. Using this analytical method, the extraction of these compounds from the tealeaves with hot water is compared under different temperatures. The effects of temperature on the amount of catechins and caffeine extracted are evident, showing that (-)-epigallocatechin gallate is the most easiest to be extracted at 100℃. The stability of catechins and caffeine in stocking solution of tea-drink at 4℃ is also compared on five consecutive days. The contents of catechins and caffeine in green and black teas are discussed and the difference of the content between different tealeaves can provide a reference for the assessment of tea quality.
文摘Vitellogenin (Vtg) is the precursor of yolk protein. Its expression and secretion are estrogen-regulated and are crucial for oocyte maturation. An in vitro xenoestro- gen screening model was established by measuring Vtg in- duction in cultured primary hepatocytes from crucian carp. Vtg production was detected by biotin-avidin sandwich ELISA method while Vtg and cytochrome P4501A1 (CYP1A1) mRNA induction were measured by semi- quan- titative PCR-primer dropping technique. Vtg and Vtg mRNA were dose-dependently induced by diethylstilbestrol (DES, 0.2—200 ng/mL) in hepatocytes of crucian carp. Co-treatment of the DES-induced hepatocytes with either 2,3,7,8-TCDD (TCDD, 0.1—4 pg/mL) or benzo[a]pyrene (B[a]P, 5—1000 ng/mL) resulted in a reduction of Vtg pro- duction and an increment of CYP1A1 mRNA expression both in a dose dependent manner, indicating the anti-estro- genic effects of the compounds. However, at lower tested concentrations, TCDD (0.1, 0.2 pg/mL), B[a]P (5 ng/mL) seemed to have a potentiating effect on Vtg expression and secretion, although by their own these compounds had no observable estrogenic effect on Vtg induction. Tamoxifen (a selective estrogen receptor modulators, 1 nmol/L—1 μmol/L), and β-naphtho-flavone (β-NF, an aryl hydrocarbon receptor inducing compounds, 2.5—1000 ng/mL) also were employed to study the possible interactions in DES-induced Vtg ex- pression. In co-treatment of the DES-induced hepatocytes with β-NF or tamoxifen, the decrease in Vtg production did parallel induction of CYP1A1 for β-NF, but tamoxifen inhib- ited Vtg induction did not parallel induced CYP1A1 expres- sion in all test concentrations. On the contrary, it was found that in co-treatment of the TCDD-induced hepatocytes with DES, TCDD induced CYP1A1 mRNA production was inhib- ited by DES also. These results implicated a possible cross talk between estrogen receptor- and aryl hydrocarbon re- ceptor-mediated pathways in the hepatocytes.
文摘Recent developments in studies of directed transport processes in interacting particle systems are retrospected. Due to the interactions among elements, the directed transport process exhibits complicated and novel cooperative dynamics. We considered various possibilities in achieving ratchet motion by breaking different symmetries of many-body systems. It is shown that the directional transport can even be induced by breaking the coupling symmetry and the spatiotemporal symmetries.
文摘The aim of this paper is to develop a fast numerical method for two-dimensional boundary integral equations of the first kind with logarithm kernels when the boundary of the domain is smooth and closed. In this case, the use of the conventional boundary element methods gives linear systems with dense matrix. In this paper, we demonstrate that the dense matrix can be replaced by a sparse one if appropriate graded meshes are used in the quadrature rules. It will be demonstrated that this technique can increase the numerical efficiency significantly.
基金香港研究资助局资助项目，the Hong Kong Baptist University Faculty Research Grant(FRG)，国家自然科学基金，国家重点基础研究发展计划(973计划)
文摘A novel approach is presented for measuring the phase synchronization (frequency-locking) of coupled nonidentical oscillators, which can characterize frequency-locking for chaotic systems without well-defined phase by measuring the mean frequency. Numerical simulations confirm the existence of frequency-locking. The relations between the mean frequency and the coupling strength and the frequency mismatch are given. For the coupled hyperchaotic systems, the frequency-locking can be better characterized by more than one mean frequency curves.
基金Project supported by the National Natural Science Foundation of China(No.40101005),the Provincial Natural Science Foundation of Shandong(No.Q2002E03)and the Provincial Education Committee of Shandong(No.J02L01).
文摘Pot-grown tomato plants (Lycopersicon esculentum Mill. cv. Maofen) was used to study the effects of three shading levels (0, 75% and 40%) for 8 days on dry matter partitioning, contents of nitrogen (N), phosphorus (P) and potassium (K) in leaves arid yield at three growth stages (early flowering (EF), peak flowering (PF) and later flowering (LF)). Shading reduced the dry weight of root and stem tissues at the EF and PF stages, but the 40% shading increased root dry weight and stem dry weight by 43.2% and 21.6%, respectively, at the LF stage. The influence of shading on the dry weight of leaves was very small at most growth stages. Shading had no effects on total leaf N, P and K contents at the EF and PF stages, showing that N, P and K absorption were regulated by the carbon assimilation at these two stages. The leaf N, P and K contents of 40% shaded plants at the LF stage were significantly increased. There were no obvious differences in leaf N and K contents between 75% and 40% shading treatments, but significant difference in leaf P contents was found between them at the LF stage. Shading significantly enhanced the fruit yield of 40% shaded tomato plants at the LF stage, but failed to affect the fruit yield of shaded plants at the EF stage. These showed that tomato could grow well and a better yield could be obtained if some moderate shading (i.e., 40% shading) was applied at the LF stage at summer midday.
文摘Introduced the characteristics of series communicat io n I 2C bus and basic communication protocol, and introduced the application of the bus I 2C according to the image sensor OV7610.The computer correspondence s tyle can be divided the parallel correspondence and the series correspondence. T he rate of series correspondence is rapid, and the property of real time is exce llent. Because the number of ports which it takes is great, it is not proper to miniaturize. Whereas the rate of series correspondence is low, but when the corr espondence of data is not great, it is simpleconvenient and agile to dispose t he circuit. Commonly series correspondence divide synchronization correspondence and asynchronies correspondence. The standard of interface RC232 is series asyn chronies correspondence. Recently the standard of bus I 2C is adopted widely in the micro-electronics correspondence realm, it is a special form of synchr onization correspondence. I 2C bus is a two-cabledouble-direction series co rrespondence bus. The address of the machine is set in hardware, and software pe rform the search of the address instead of hardware. So it reduce the number of the corresponding cable, moreover it predigest the design of the hardware. It resolve many interface problems in design of numeric circuit. More and more se miconductor manufacturer accept the standard. Its characteristics can be listed as followed. In text, the image sensor OV7610 is introduced as the example the bus I 2C appl ication.
文摘Concentrations of C-reactive protein (CRP) in the serum of 14 patients suffering from Lyme diseasc were measured. 86% of these patients were found to have abnormally high concentrations of serum CRP (range 14-158 mg/L). The CRP concentration of a 60-yearold patient abated from 29 mg/L to 13 mg/L after treatrnent. Results suggest that serum CRP concentration can provide a valuable and accurate means for the clinical diagnosis and monitoring of Lyme disease
基金Project supported by the National Natural Science Foundation of China (No.19801020) and the grant from the Research Grants Coun
文摘Let X = {Xt,t >=0} be a d-dimensional (d>= 2) standard Brownian motion with drift c started at a fixed x, and BR = {x E Rd: |x| < R}, the ball centered at 0 with radius R. Consider the distributions of TR(t) and TR(∞), where TR(t) denotes the time spent by X in BR up to time t and TR(∞) the total time of X spent in BR. Explicit formulas for the Laplace transform of TR(∞) and the double Laplace transform of TR(t) are obtained.
