Aim To investigate novel bioactive and structural metabolites from marineorganisms. Methods Column chromatography in association with semi-preparative HPLC were used for theisolation of compounds. 1D and 2D NMR, IR, U...Aim To investigate novel bioactive and structural metabolites from marineorganisms. Methods Column chromatography in association with semi-preparative HPLC were used for theisolation of compounds. 1D and 2D NMR, IR, UV, and MS were employed for structure elucidation.Results From the butanol fraction of the 95% EtOH extract of the starfish Asterias rollestoni, a newcompound N^7 -2'-deoxypseudoxanthosine (1), along with sixteen known compounds, 2'-0-methyl-inosine(2), 2'-deoxyinosine (3), 2'-0-methylguanosine (4), inosine (5); thymine (6), uracil (7), thymidine(8), deoxyuridine (9), 2'-0-methyluridine (10), ( ― )-(1S, 3S)-1-methyl-1, 2, 3,4-terrahydro-β-carboline-3-carboxyl-ic acid (11), ( ― )-(1R, 3S)-1-methyl-1, 2, 3,4-tetrahydro-β-carboline-3-carboxylic acid (12) , ( ― )-(3S)- 1, 2, 3,4-tetrahydro-β-carboline-3-carboxylic acid (13), L-tryptophan (14), L-phenylalanine (15), 3-carboxyindole (16), and p-hydroxybenzoic acid (17) , have been isolated. Conclusion Compound 1 is a newnatural product, and compounds 8, 9 and 10 are isolated from natural sources for the first time, andthe known compounds except 14 and 15 are first reported from starfish Asterias rollestoni.展开更多
Using the method of mathematical morphology,this paper fulfills filtration,segmentation and extraction of morphological features of the satellite cloud image.It also gives out the relative algorithms,which is realized...Using the method of mathematical morphology,this paper fulfills filtration,segmentation and extraction of morphological features of the satellite cloud image.It also gives out the relative algorithms,which is realized by parallel C programming based on Transputer networks.It has been successfully used to process the typhoon and the low tornado cloud image.And it will be used in weather forecast.展开更多
As the only source of stem cells, satellite cells play and extraordinary role in the remediation process of skeletal muscle after injury. This paper overviewed the biological characteristic of skeletal muscle satellit...As the only source of stem cells, satellite cells play and extraordinary role in the remediation process of skeletal muscle after injury. This paper overviewed the biological characteristic of skeletal muscle satellite cells and its role in repairing muscle injury, and put forward the prospects of its application in muscle trauma repair.展开更多
Iron is an essential element involved in various biological pathways. When present in excess within the cell, iron can be toxic due to its ability to catalyse the formation of damaging radicals, which promote cellular...Iron is an essential element involved in various biological pathways. When present in excess within the cell, iron can be toxic due to its ability to catalyse the formation of damaging radicals, which promote cellular injury and cell death. Within the liver, iron related oxidative stress can lead to fibrosis and ultimately to cirrhosis. Here we review the role of excessive iron in the pathologies associated with various chronic diseases of the liver. We also describe the molecular mechanism by which iron contributes to the development of hepatic fibrosis.展开更多
A patented double-ring-plate gear reducer was designed and its dynamic performance was simulated. One unique characteristic of this novel drive is that the phase angle difference between two parallelogram mechanisms i...A patented double-ring-plate gear reducer was designed and its dynamic performance was simulated. One unique characteristic of this novel drive is that the phase angle difference between two parallelogram mechanisms is a little less than 180 degree and four counterweights on two crankshafts are designed to balance inertia forces and inertia moments of the mechanisms. Its operating principle, advantages, and design issues were discussed. An elasto-dynamics model was presented to acquire its dynamic response by considering the elastic deformations of ring-plates, gears, bearings, etc. The simulation results reveal that compared with housing bearings, planetary bearings work in more severe conditions. The fluctuation of loads on gears and bearings indicates that the main reason for reducer vibration is elastic deformations of the system rather than inertia forces and inertia moments of the mechanisms.展开更多
The thermal elasto-hydrodynamic lubrication characteristics of the internal meshing gears in a planetary gear train under vibrations were examined considering the influence of the modification coefficient and time-var...The thermal elasto-hydrodynamic lubrication characteristics of the internal meshing gears in a planetary gear train under vibrations were examined considering the influence of the modification coefficient and time-varying meshing stiffness.Based on dynamic theory of the gear system,a dynamic model of the planetary gear train was established.The lubrication performances of modified gear systems under vibrations and static loads were analyzed.Compared with other transmission types,the best lubrication effect could be produced by the positive transmission.A thicker lubricating oil film could be formed,and the friction coefficient and oil film flash temperature are the smallest.Increasing modification coefficient improves the lubrication performance continuously but intensifies the engage-in and tooth-change impact.For the planetary and inner gears,the increase in the modification coefficient also leads a decrease in the oil film stiffness.展开更多
To compare liver proteolysis and proteasome activation in steatotic liver grafts conserved in University of Wisconsin (UW) and Institut Georges Lopez-1 (IGL-1) solutions.METHODSFatty liver grafts from male obese Z...To compare liver proteolysis and proteasome activation in steatotic liver grafts conserved in University of Wisconsin (UW) and Institut Georges Lopez-1 (IGL-1) solutions.METHODSFatty liver grafts from male obese Zücker rats were conserved in UW and IGL-1 solutions for 24 h at 4 °Cand subjected to “ex vivo” normo-thermic perfusion (2 h; 37 °C). Liver proteolysis in tissue specimens and perfusate was measured by reverse-phase high performance liquid chromatography. Total free amino acid release was correlated with the activation of the ubiquitin proteasome system (UPS: measured as chymotryptic-like activity and 20S and 19S proteasome), the prevention of liver injury (transaminases), mitochondrial injury (confocal microscopy) and inflammation markers (TNF 1 alpha, high mobility group box-1 (HGMB-1) and PPAR gamma), and liver apoptosis (TUNEL assay, cytochrome c and caspase 3).RESULTSProfiles of free AA (alanine, proline, leucine, isoleucine, methionine, lysine, ornithine, and threonine, among others) were similar for tissue and reperfusion effluent. In all cases, the IGL-1 solution showed a significantly higher prevention of proteolysis than UW (P < 0.05) after cold ischemia reperfusion. Livers conserved in IGL-1 presented more effective prevention of ATP-breakdown and more inhibition of UPS activity (measured as chymotryptic-like activity). In addition, the prevention of liver proteolysis and UPS activation correlated with the prevention of liver injury (AST/ALT) and mitochondrial damage (revealed by confocal microscopy findings) as well as with the prevention of inflammatory markers (TNF1alpha and HMGB) after reperfusion. In addition, the liver grafts preserved in IGL-1 showed a significant decrease in liver apoptosis, as shown by TUNEL assay and the reduction of cytochrome c, caspase 3 and P62 levels.CONCLUSIONOur comparison of these two preservation solutions suggests that IGL-1 helps to prevent ATP breakdown more effectively than UW and subsequently achieves a higher UPS inhibition and reduced liver proteolysis.展开更多
I type system model of CCCAM(Contention-Collision Cancellation Access Mode) is studied through mathematical modelling and simulation. There are two innovations: (1) in the process of mathematical modelling, the instan...I type system model of CCCAM(Contention-Collision Cancellation Access Mode) is studied through mathematical modelling and simulation. There are two innovations: (1) in the process of mathematical modelling, the instance of 'serving customers unsuccessfully' is taken into account; (2) the time at which customers depart after having been served successfully are chosen to be the embedded point, thereby 'free period' is introduced reasonably. So the mathematical modelling and analysis result in this paper are significant for application of wire star LAN and wireless star LAN.展开更多
Stars with masses between 1 and 8 solar masses(M⊙)lose large amounts of material in the form of gas and dust in the late stages of stellar evolution,during their Asymptotic Giant Branch(AGB)phase.Such stars supply up...Stars with masses between 1 and 8 solar masses(M⊙)lose large amounts of material in the form of gas and dust in the late stages of stellar evolution,during their Asymptotic Giant Branch(AGB)phase.Such stars supply up to 35%of the dust in the interstellar medium and thus contribute to the material out of which our solar system formed.In addition,the circumstellar envelopes of these stars are sites of complex organic chemistry with over 80 molecules detected in them.We show that internal ultraviolet photons,either emitted by the star itself or from a close-in,orbiting companion,can significantly alter the chemistry that occurs in the envelopes particularly if the envelope is clumpy in nature.At least for the cases explored here,we find that in the presence of a stellar companion,such as a white dwarf star,the high flux of UV photons destroys H2O in the inner regions of carbon-rich AGB stars to levels below those observed and produces species such as C^+deep in the envelope in contrast to the expectations of traditional descriptions of circumstellar chemistry.展开更多
According to a review article by Biecker et al published in a previous issue of World Journal of Gastroenterology in March 2011,intestinal decontamination with norfloxacin remains the mainstay of primary prophylaxis o...According to a review article by Biecker et al published in a previous issue of World Journal of Gastroenterology in March 2011,intestinal decontamination with norfloxacin remains the mainstay of primary prophylaxis of spontaneous bacterial peritonitis(SBP) at the expense of development of quinolone-resistant bacteria after long-term use.In our research,the administration of a 4-wk regimen with rifaximin 1200 mg/d reduced significantly the ascitic neutrophil count in cirrhotic patients with sterile ascites in line with a significant decrease in plasma endotoxin levels.Our observations concur with recent findings,showing a significantly reduced 5-year probability of SBP in cirrhotic patients taking rifaximin.展开更多
As one of the masterpieces for Don Delillo, Libra was regarded as a classic postmodern novel once after its publication. Based on Kennedy assassination, this novel mainly deals with the isolation and dissimilation fee...As one of the masterpieces for Don Delillo, Libra was regarded as a classic postmodern novel once after its publication. Based on Kennedy assassination, this novel mainly deals with the isolation and dissimilation feelings for the American citizens. As a representative postmodern novel, Libra's stylistic features and narrative strategies are both quite typical. This thesis will discuss its narrative angles, its narrative structure and its dialogue expressions in order to understand Libra's postmodern narrative technique.展开更多
Objective.To investigate PTEN expression and loss of heterozygosity(LOH)of its epigenetic microsatel-lites in gastric carcinoma and explore their roles in tumorigenesis and progression of gastric carcinoma.Methods.LOH...Objective.To investigate PTEN expression and loss of heterozygosity(LOH)of its epigenetic microsatel-lites in gastric carcinoma and explore their roles in tumorigenesis and progression of gastric carcinoma.Methods.LOH of epigenetic microsatellites of PTEN(D10S541,D10S583and D10S1687)was exam-ined in advanced gastric carcinomas(n=56)by PCR-SSCP.The mRNA and protein expressions of PTEN gene were evaluated in normal mucosa(n=56),early(n=11)and advanced carcinomas(n=56)of the stomach using RT?PCR and immunohistochemoistry respectively.PTEN mRNA and protein expressions were compared with clinicopathological staging and lymph node metastasis of tumors.The relationship be-tween PTEN mRNA expression and LOH of microsatellites was discussed,as well as relationship between PTEN mRNA and protein expression.Results.LOH of D10S541,D10S583and D10S1687was found in28.6%(16/56)of advanced gas-tric carcinomas.The positive rates of PTEN expression were80.4%(45/56),45.5%(5/11)and32.1%(18/56)in normal gastric mucosa,early and advanced gastric carcinomas at mRNA level,while78.6%(44/56),36.4%(4/11)and28.6%(16/56)at protein level.PTEN mRNA and protein were less fre-quently expressed in early and advanced gastric carcinomas than normal gastric mucosa(P<0.05).There was negative correlation between PTEN mRNA expression and LOH of microsatellites(P<0.05).PTEN protein expression paralleled to its mRNA expression(P<0.05).The PTEN mRNA and protein expres-sions were negatively correlated with lymph node metastasis of advanced gastric carcinomas(P<0.05).Conclusion.Down?regulated expression of PTEN and frequent LOH of its epigenetic microsatellites might play an important role in gastric carcinogenesis.Reduced PTEN mRNA expression was closely as-sociated with LOH of its epigenetic microsatellites.Altered expression of PTEN might contribute to lymph node metastasis of gastric carcinoma by decreasing cell adhesion and apoptosis,increasing angiogenesis and cell mobility.展开更多
AIM: To study the effect of rosiglitazone, which is a ligand of peroxisome proliferator-activated receptor gamma (PPARy), on the expression of PPARy in hepatic stellate cells (HSCs) and on the biological characte...AIM: To study the effect of rosiglitazone, which is a ligand of peroxisome proliferator-activated receptor gamma (PPARy), on the expression of PPARy in hepatic stellate cells (HSCs) and on the biological characteristics of HSCs. METHODS: The activated HSCs were divided into three groups: control group, 3 μmol/L rosiglitazone group, and 10 μmol/L rosiglitazone group. The expression of PPARγ, α-smooth muscle actin (α-SMA), and type Ⅰ and Ⅲ collagen was detected by RT-PCR, Western blot and immunocytochemical staining, respectively. Cell proliferation was determined with methylthiazolyltetrazolium (MTT) colodmetric assay. Cell apoptosis was demonstrated with flow cytometry. RESULTS: The expression of PPARγ at mRNA and protein level markedly increased in HSCs of 10 μmol/L rosiglitazone group (tvalue was 10.870 and 4.627 respectively, P〈0.01 in both). The proliferation of HSCs in 10 μmol/L rosiglitazone group decreased significantly (t = 5.542, P〈0.01), α-SMA expression level and type Ⅰ collagen synthesis ability were also reduced VS controls (tvalue = 10.256 and 14.627 respectively, P〈0.01 in both). The apoptotic rate of HSCs significantly increased in 10 μmol/L rosiglitazone group vs control (X^2= 16.682, P〈0.01). CONCLUSION: By increasing expression of PPARγ in activated HSCs, rosiglitazone, an agonist of PPARγ, decreases α-SNA expression and type Ⅰ collagen synthesis, inhibits cell proliferation, and induces cell apoptosis.展开更多
Using 10-year (2001 10) monthly evaporation, precipitation, and sea surface salinity (SSS) datasets, the relationship between local freshwater flux and SSS in the north Indian Ocean (NIO) is evaluated quantitatively. ...Using 10-year (2001 10) monthly evaporation, precipitation, and sea surface salinity (SSS) datasets, the relationship between local freshwater flux and SSS in the north Indian Ocean (NIO) is evaluated quantitatively. The results suggest a highly positive linear correlation between freshwater flux and SSS in the Arabian Sea (correlation coefficient, R=0.74) and the western equatorial Indian Ocean (R=0.73), whereas the linear relationships are relatively weaker in the Bay of Bengal (R=0.50) and the eastern equatorial Indian Ocean (R=0.40). Additionally, the interannual variations of freshwater flux and SSS and their mutual relationship are investigated in four sub- regions for pre-monsoon, monsoon, and post-monsoon seasons separately. The satellite retrievals of SSS from the Soil Moisture and Ocean Salinity (SMOS) and Aquarius missions can provide continuous and consistent SSS fields for a better understanding of its variability and the differences between the freshwater flux and SSS signals, which are commonly thought to be linearly related.展开更多
We consider a generalized spin star configuration that can be solved exactly, with the central spin-1/2 system embedded in an outer ring of N spin-1/2 particles (denoted as spin bath). In this model, we consider a m...We consider a generalized spin star configuration that can be solved exactly, with the central spin-1/2 system embedded in an outer ring of N spin-1/2 particles (denoted as spin bath). In this model, we consider a modified version of the spin star model, by taking into account, besides the interaction of the central spin with the bath, the interactions between the spins of the bath as well. The general expressions of the eigenstates as well as the eigenvalues of the model are derived with the use of the symmetries of system. We then investigate the properties of the ground quantum phase transitions in some limiting cases in the model and show that the occurrence of quantum phase transitions and the desired ground states can be obtained by varying the external control parameters.展开更多
This paper reviews the recoverable satellites China has developed over the past forty years.The main missions,technical specifications,scientific and technical experiments of these satellites,including the SJ-10 scien...This paper reviews the recoverable satellites China has developed over the past forty years.The main missions,technical specifications,scientific and technical experiments of these satellites,including the SJ-10 scientific experiment satellite launched on April 6,2016 are introduced.Recommendations for future technical upgrades for recoverable satellites are also proposed in the paper.展开更多
文摘Aim To investigate novel bioactive and structural metabolites from marineorganisms. Methods Column chromatography in association with semi-preparative HPLC were used for theisolation of compounds. 1D and 2D NMR, IR, UV, and MS were employed for structure elucidation.Results From the butanol fraction of the 95% EtOH extract of the starfish Asterias rollestoni, a newcompound N^7 -2'-deoxypseudoxanthosine (1), along with sixteen known compounds, 2'-0-methyl-inosine(2), 2'-deoxyinosine (3), 2'-0-methylguanosine (4), inosine (5); thymine (6), uracil (7), thymidine(8), deoxyuridine (9), 2'-0-methyluridine (10), ( ― )-(1S, 3S)-1-methyl-1, 2, 3,4-terrahydro-β-carboline-3-carboxyl-ic acid (11), ( ― )-(1R, 3S)-1-methyl-1, 2, 3,4-tetrahydro-β-carboline-3-carboxylic acid (12) , ( ― )-(3S)- 1, 2, 3,4-tetrahydro-β-carboline-3-carboxylic acid (13), L-tryptophan (14), L-phenylalanine (15), 3-carboxyindole (16), and p-hydroxybenzoic acid (17) , have been isolated. Conclusion Compound 1 is a newnatural product, and compounds 8, 9 and 10 are isolated from natural sources for the first time, andthe known compounds except 14 and 15 are first reported from starfish Asterias rollestoni.
文摘Using the method of mathematical morphology,this paper fulfills filtration,segmentation and extraction of morphological features of the satellite cloud image.It also gives out the relative algorithms,which is realized by parallel C programming based on Transputer networks.It has been successfully used to process the typhoon and the low tornado cloud image.And it will be used in weather forecast.
文摘As the only source of stem cells, satellite cells play and extraordinary role in the remediation process of skeletal muscle after injury. This paper overviewed the biological characteristic of skeletal muscle satellite cells and its role in repairing muscle injury, and put forward the prospects of its application in muscle trauma repair.
文摘Iron is an essential element involved in various biological pathways. When present in excess within the cell, iron can be toxic due to its ability to catalyse the formation of damaging radicals, which promote cellular injury and cell death. Within the liver, iron related oxidative stress can lead to fibrosis and ultimately to cirrhosis. Here we review the role of excessive iron in the pathologies associated with various chronic diseases of the liver. We also describe the molecular mechanism by which iron contributes to the development of hepatic fibrosis.
基金Supported by the Key Project of Ministry of Education of China ( No.106050)National Natural Science Foundation of China(No.50205019)Doctoral Foundation of Ministry of Education of China(No.20040056018) .
文摘A patented double-ring-plate gear reducer was designed and its dynamic performance was simulated. One unique characteristic of this novel drive is that the phase angle difference between two parallelogram mechanisms is a little less than 180 degree and four counterweights on two crankshafts are designed to balance inertia forces and inertia moments of the mechanisms. Its operating principle, advantages, and design issues were discussed. An elasto-dynamics model was presented to acquire its dynamic response by considering the elastic deformations of ring-plates, gears, bearings, etc. The simulation results reveal that compared with housing bearings, planetary bearings work in more severe conditions. The fluctuation of loads on gears and bearings indicates that the main reason for reducer vibration is elastic deformations of the system rather than inertia forces and inertia moments of the mechanisms.
基金Projects(51575289,51705270)supported by the National Natural Science Foundation of China。
文摘The thermal elasto-hydrodynamic lubrication characteristics of the internal meshing gears in a planetary gear train under vibrations were examined considering the influence of the modification coefficient and time-varying meshing stiffness.Based on dynamic theory of the gear system,a dynamic model of the planetary gear train was established.The lubrication performances of modified gear systems under vibrations and static loads were analyzed.Compared with other transmission types,the best lubrication effect could be produced by the positive transmission.A thicker lubricating oil film could be formed,and the friction coefficient and oil film flash temperature are the smallest.Increasing modification coefficient improves the lubrication performance continuously but intensifies the engage-in and tooth-change impact.For the planetary and inner gears,the increase in the modification coefficient also leads a decrease in the oil film stiffness.
基金Supported by Instituto de Salud Carlos III(ISCIII)through the FIS project PI12/0056,co-funded by FEDER from Regional Development European Funds(European Union)
文摘To compare liver proteolysis and proteasome activation in steatotic liver grafts conserved in University of Wisconsin (UW) and Institut Georges Lopez-1 (IGL-1) solutions.METHODSFatty liver grafts from male obese Zücker rats were conserved in UW and IGL-1 solutions for 24 h at 4 °Cand subjected to “ex vivo” normo-thermic perfusion (2 h; 37 °C). Liver proteolysis in tissue specimens and perfusate was measured by reverse-phase high performance liquid chromatography. Total free amino acid release was correlated with the activation of the ubiquitin proteasome system (UPS: measured as chymotryptic-like activity and 20S and 19S proteasome), the prevention of liver injury (transaminases), mitochondrial injury (confocal microscopy) and inflammation markers (TNF 1 alpha, high mobility group box-1 (HGMB-1) and PPAR gamma), and liver apoptosis (TUNEL assay, cytochrome c and caspase 3).RESULTSProfiles of free AA (alanine, proline, leucine, isoleucine, methionine, lysine, ornithine, and threonine, among others) were similar for tissue and reperfusion effluent. In all cases, the IGL-1 solution showed a significantly higher prevention of proteolysis than UW (P < 0.05) after cold ischemia reperfusion. Livers conserved in IGL-1 presented more effective prevention of ATP-breakdown and more inhibition of UPS activity (measured as chymotryptic-like activity). In addition, the prevention of liver proteolysis and UPS activation correlated with the prevention of liver injury (AST/ALT) and mitochondrial damage (revealed by confocal microscopy findings) as well as with the prevention of inflammatory markers (TNF1alpha and HMGB) after reperfusion. In addition, the liver grafts preserved in IGL-1 showed a significant decrease in liver apoptosis, as shown by TUNEL assay and the reduction of cytochrome c, caspase 3 and P62 levels.CONCLUSIONOur comparison of these two preservation solutions suggests that IGL-1 helps to prevent ATP breakdown more effectively than UW and subsequently achieves a higher UPS inhibition and reduced liver proteolysis.
基金Supported by Natural Science Foundation of Qingdao University
文摘I type system model of CCCAM(Contention-Collision Cancellation Access Mode) is studied through mathematical modelling and simulation. There are two innovations: (1) in the process of mathematical modelling, the instance of 'serving customers unsuccessfully' is taken into account; (2) the time at which customers depart after having been served successfully are chosen to be the embedded point, thereby 'free period' is introduced reasonably. So the mathematical modelling and analysis result in this paper are significant for application of wire star LAN and wireless star LAN.
文摘Stars with masses between 1 and 8 solar masses(M⊙)lose large amounts of material in the form of gas and dust in the late stages of stellar evolution,during their Asymptotic Giant Branch(AGB)phase.Such stars supply up to 35%of the dust in the interstellar medium and thus contribute to the material out of which our solar system formed.In addition,the circumstellar envelopes of these stars are sites of complex organic chemistry with over 80 molecules detected in them.We show that internal ultraviolet photons,either emitted by the star itself or from a close-in,orbiting companion,can significantly alter the chemistry that occurs in the envelopes particularly if the envelope is clumpy in nature.At least for the cases explored here,we find that in the presence of a stellar companion,such as a white dwarf star,the high flux of UV photons destroys H2O in the inner regions of carbon-rich AGB stars to levels below those observed and produces species such as C^+deep in the envelope in contrast to the expectations of traditional descriptions of circumstellar chemistry.
文摘According to a review article by Biecker et al published in a previous issue of World Journal of Gastroenterology in March 2011,intestinal decontamination with norfloxacin remains the mainstay of primary prophylaxis of spontaneous bacterial peritonitis(SBP) at the expense of development of quinolone-resistant bacteria after long-term use.In our research,the administration of a 4-wk regimen with rifaximin 1200 mg/d reduced significantly the ascitic neutrophil count in cirrhotic patients with sterile ascites in line with a significant decrease in plasma endotoxin levels.Our observations concur with recent findings,showing a significantly reduced 5-year probability of SBP in cirrhotic patients taking rifaximin.
文摘As one of the masterpieces for Don Delillo, Libra was regarded as a classic postmodern novel once after its publication. Based on Kennedy assassination, this novel mainly deals with the isolation and dissimilation feelings for the American citizens. As a representative postmodern novel, Libra's stylistic features and narrative strategies are both quite typical. This thesis will discuss its narrative angles, its narrative structure and its dialogue expressions in order to understand Libra's postmodern narrative technique.
文摘Objective.To investigate PTEN expression and loss of heterozygosity(LOH)of its epigenetic microsatel-lites in gastric carcinoma and explore their roles in tumorigenesis and progression of gastric carcinoma.Methods.LOH of epigenetic microsatellites of PTEN(D10S541,D10S583and D10S1687)was exam-ined in advanced gastric carcinomas(n=56)by PCR-SSCP.The mRNA and protein expressions of PTEN gene were evaluated in normal mucosa(n=56),early(n=11)and advanced carcinomas(n=56)of the stomach using RT?PCR and immunohistochemoistry respectively.PTEN mRNA and protein expressions were compared with clinicopathological staging and lymph node metastasis of tumors.The relationship be-tween PTEN mRNA expression and LOH of microsatellites was discussed,as well as relationship between PTEN mRNA and protein expression.Results.LOH of D10S541,D10S583and D10S1687was found in28.6%(16/56)of advanced gas-tric carcinomas.The positive rates of PTEN expression were80.4%(45/56),45.5%(5/11)and32.1%(18/56)in normal gastric mucosa,early and advanced gastric carcinomas at mRNA level,while78.6%(44/56),36.4%(4/11)and28.6%(16/56)at protein level.PTEN mRNA and protein were less fre-quently expressed in early and advanced gastric carcinomas than normal gastric mucosa(P<0.05).There was negative correlation between PTEN mRNA expression and LOH of microsatellites(P<0.05).PTEN protein expression paralleled to its mRNA expression(P<0.05).The PTEN mRNA and protein expres-sions were negatively correlated with lymph node metastasis of advanced gastric carcinomas(P<0.05).Conclusion.Down?regulated expression of PTEN and frequent LOH of its epigenetic microsatellites might play an important role in gastric carcinogenesis.Reduced PTEN mRNA expression was closely as-sociated with LOH of its epigenetic microsatellites.Altered expression of PTEN might contribute to lymph node metastasis of gastric carcinoma by decreasing cell adhesion and apoptosis,increasing angiogenesis and cell mobility.
基金Supported by the National Natural Science Foundation of China,No. 30371387
文摘AIM: To study the effect of rosiglitazone, which is a ligand of peroxisome proliferator-activated receptor gamma (PPARy), on the expression of PPARy in hepatic stellate cells (HSCs) and on the biological characteristics of HSCs. METHODS: The activated HSCs were divided into three groups: control group, 3 μmol/L rosiglitazone group, and 10 μmol/L rosiglitazone group. The expression of PPARγ, α-smooth muscle actin (α-SMA), and type Ⅰ and Ⅲ collagen was detected by RT-PCR, Western blot and immunocytochemical staining, respectively. Cell proliferation was determined with methylthiazolyltetrazolium (MTT) colodmetric assay. Cell apoptosis was demonstrated with flow cytometry. RESULTS: The expression of PPARγ at mRNA and protein level markedly increased in HSCs of 10 μmol/L rosiglitazone group (tvalue was 10.870 and 4.627 respectively, P〈0.01 in both). The proliferation of HSCs in 10 μmol/L rosiglitazone group decreased significantly (t = 5.542, P〈0.01), α-SMA expression level and type Ⅰ collagen synthesis ability were also reduced VS controls (tvalue = 10.256 and 14.627 respectively, P〈0.01 in both). The apoptotic rate of HSCs significantly increased in 10 μmol/L rosiglitazone group vs control (X^2= 16.682, P〈0.01). CONCLUSION: By increasing expression of PPARγ in activated HSCs, rosiglitazone, an agonist of PPARγ, decreases α-SNA expression and type Ⅰ collagen synthesis, inhibits cell proliferation, and induces cell apoptosis.
文摘Using 10-year (2001 10) monthly evaporation, precipitation, and sea surface salinity (SSS) datasets, the relationship between local freshwater flux and SSS in the north Indian Ocean (NIO) is evaluated quantitatively. The results suggest a highly positive linear correlation between freshwater flux and SSS in the Arabian Sea (correlation coefficient, R=0.74) and the western equatorial Indian Ocean (R=0.73), whereas the linear relationships are relatively weaker in the Bay of Bengal (R=0.50) and the eastern equatorial Indian Ocean (R=0.40). Additionally, the interannual variations of freshwater flux and SSS and their mutual relationship are investigated in four sub- regions for pre-monsoon, monsoon, and post-monsoon seasons separately. The satellite retrievals of SSS from the Soil Moisture and Ocean Salinity (SMOS) and Aquarius missions can provide continuous and consistent SSS fields for a better understanding of its variability and the differences between the freshwater flux and SSS signals, which are commonly thought to be linearly related.
基金The project supported by National Basic Research Program of China under Grant No.2007CB925204
文摘We consider a generalized spin star configuration that can be solved exactly, with the central spin-1/2 system embedded in an outer ring of N spin-1/2 particles (denoted as spin bath). In this model, we consider a modified version of the spin star model, by taking into account, besides the interaction of the central spin with the bath, the interactions between the spins of the bath as well. The general expressions of the eigenstates as well as the eigenvalues of the model are derived with the use of the symmetries of system. We then investigate the properties of the ground quantum phase transitions in some limiting cases in the model and show that the occurrence of quantum phase transitions and the desired ground states can be obtained by varying the external control parameters.
文摘This paper reviews the recoverable satellites China has developed over the past forty years.The main missions,technical specifications,scientific and technical experiments of these satellites,including the SJ-10 scientific experiment satellite launched on April 6,2016 are introduced.Recommendations for future technical upgrades for recoverable satellites are also proposed in the paper.