Objectives To identify the 5'untranslated region of Zika virus(ZIKV 5'UTR)RNA-binding proteins and to investigate the impact of the binding protein on the activity of internal ribosomal entry site(IRES)located...Objectives To identify the 5'untranslated region of Zika virus(ZIKV 5'UTR)RNA-binding proteins and to investigate the impact of the binding protein on the activity of internal ribosomal entry site(IRES)located in ZIKV 5'UTR and virus production.Methods Interacting proteins in U251 cells were captured using tRSA-tagged ZIKV 5'UTR RNA and tRSA-ZIKV 5'UTR RNA-binding proteins were visualized by SDS-PAGE silver staining,Subsequently,liquid chromatographytandem mass spectrometry(LC-MS/MS),bioinformatics analysis,and Western blot were used to identify the candidate proteins binding to ZIKV 5'UTR.Dicistronic expression assay and plaque forming assay were performed to analyze the effect of the binding protein on ZIKV IRES activity and ZIKV production,respecitvely.Results tRSA RNA pull-down assay,LC-MS/MS,and Western blot analysis showed that polypyrimidine tractbinding protein(PTB)bound to the ZIKV 5'UTR.Furthermore,dual luciferase reporter assay revealed that overexpression of PTB significantly enhanced the IRES activity of ZIKV(t=10.220,P<0.001),while PTB knockdown had the opposite effect(t=4.897,P<0.01).Additionally,virus plaque forming assay demonstrated that up-regulation of PTB expression significantly enhanced viral titer(t=6.400,P<0.01),whereas reducing PTB expression level weakened virus infectivity(t=5.055,P<0.01).Conclusion PTB positively interacts with the ZIKV 5'UTR and enhances IRES activity and virus production.展开更多
Objective To study the central role of ginkgolide B (BN52021) in regulating cardiovascular function of nerve center by examining the effects of ginkgolide B on the electrical activity of rat paraventricular nucleus ...Objective To study the central role of ginkgolide B (BN52021) in regulating cardiovascular function of nerve center by examining the effects of ginkgolide B on the electrical activity of rat paraventricular nucleus (PVN) neurons in hypothalamic slice preparation and to elucidate the mechanism involved. Methods Extracellular single-unit discharge recording technique. Results (1) In response to the application of ginkgolide t3 (0.1, 1, 10 μmol/L; n = 27) into the perfusate for 2 rain, the spontaneous discharge rates (SDR) of 26 (26/27, 96.30%) neurons were significantly decreased in a dose-dependent manner. (2) Pretreatment with L-glutamate (L-Glu, 0.2 mmol/L) led to a marked increase in the SDR of all 8 (100%) neurons in an epileptiform pattern. The increased discharges were suppressed significantly after ginkgolide B (1 μmol/L) was applied into the perfusate for 2 min. (3) In 8 neurons, perfusion of the selective L-type calcium channel agonist, Bay K 8644 (0.1 μmol/L), induced a significant increase in the discharge rates of 8 (8/8, 100%) neurons, while ginkgolide B (1μmol/L) applied into the perfusate, could inhibit the discharges of 8 (100%) neurons. (4) In 8 neurons, the broad potassium channels blocker, tetraethylammonium (TEA, 1 mmol/L) completely blocked the inhibitory effect of ginkgolide B (1 μmol/L). Conclusion These results suggest that ginkgolide B can inhibit the electrical activity of paraventricular neurons. The inhibitory effect may be related to the blockade of L-type voltage-activated calcium channel and potentially concerned with delayed rectifier potassium channel (KDR).展开更多
[ Objective] The aim of this study was to investigate the construction and identification of siRNA expression vector targeting nucleocapsid protein N gone of PRRSV. [Method] Three siRNA oligonucleotides targeting nucl...[ Objective] The aim of this study was to investigate the construction and identification of siRNA expression vector targeting nucleocapsid protein N gone of PRRSV. [Method] Three siRNA oligonucleotides targeting nucleocapsid protein N gone sequence of PRRSV were designed or synthesized, and then inserted into CMV promoter downstream to clone into pSilencer 4,1 -CMV eukaryotic expression vector. The recombinant expression vector was identified by enzyme digestion and DNA sequencing. [ Result] The results showed that the siRNA interference recombinant plasmid vector pSilencer-N targeting nucleocapsid protein gone expression had been successfully constructed. [ Conclusion] This study lays a foundation for studies on the controlling PRRSV by RNA interference technique .展开更多
The aim of this work was to improve the rate of conventionally blind enucleation for bovine somatic cell nuclear transfer. The cross section of a 0.5 ml Eppendorf tube was attached with a sheet of 400 mesh/inch2-cell ...The aim of this work was to improve the rate of conventionally blind enucleation for bovine somatic cell nuclear transfer. The cross section of a 0.5 ml Eppendorf tube was attached with a sheet of 400 mesh/inch2-cell screen after the bottom of the Eppendorf tube had been cut, and put into a 1 mL Eppendorf tube. In experiment 1, the oocytes in the metaphase Ⅱ stage were placed on the membrane in the Eppendorf tube, and centrifuged at 1,000, 2,000, or 3,000 r/min for 10 min, respectively. The oocytes were stained with Hoechst 33342 and then the relative position of the first polar body to the chromosomes, and the efficiency of enucleation were evaluated. In experiment 2, enucleated oocytes were fused with granulosa cells, following centrifugation and enucleation, and the potential development of the reconstituted embryos was estimated. The results indicated that the rate of enucleation in oocytes after centrifugation at 2,000 r/min for 10 min was 86.6% with an angle less then 20° between the first polar body and chromosomes. The rate of enucleation in cells spun at 2,000 r/min was higher than that of controls (87.4% vs. 64.4%, P 〈 0.05). Fur- thermore; centrifugation of recipient oocytes did not have a detrimental effect on the development of reconstituted embryos following nuclear transfer. In conclusion, centrifugation assisted enucleation may significantly improve the rate of bovine oocyte enucleation.展开更多
[ Objective] This study was to investigate the effect of VEGF and its receptor Fit-1 mRNA expression in Mongolia sheep umbilical vein endothelial cells by ghrelin antisense inhibition. [ Method] Experiments were divid...[ Objective] This study was to investigate the effect of VEGF and its receptor Fit-1 mRNA expression in Mongolia sheep umbilical vein endothelial cells by ghrelin antisense inhibition. [ Method] Experiments were divided into 4 groups: group Ⅰ (blank control group) ; group Ⅱ (liposome group) ; group Ⅲ (SCON group: 20 μmol/L sense oligonucleotide) ; group Ⅳ (ASCON: 20 μmol/L antisense oligonucleotide). VEGF and its receptor Fit-1 mRNA expression changes were detected by using real-time fluorescence quantitative detection after 24, 36 and 48 h. [ Result] The expression of VEGF mRNA in group Ⅰ, group Ⅱ were insignificantly different at higher expression levels, and did not change significantly with the time; the expression of VEGF mRNA in group Ⅲ assumed a slight decrease, but there were no significant differences between group I and group Ⅱ (P 〉0.05), the expression of VEGF mRNA in group Ⅳ(antisense oligonucleotide group ) decreased significantly (P 〈 0.05) ; the expression of VEGF receptor FLT-1 mRNA was similar to that of VEGF. [ Conclusion] Antisense inhibition ghrelin has a downward effect to the expression of VEGF and its receptor Fit-1 the mRNA.展开更多
AIM: Nuclear factor kappa B (NF-κB) regulates a large number of genes involved in the inflammatory response to critical illnesses, but it is not known if and how NF-KB is activated and intercellular adhesion molecule...AIM: Nuclear factor kappa B (NF-κB) regulates a large number of genes involved in the inflammatory response to critical illnesses, but it is not known if and how NF-KB is activated and intercellular adhesion molecule-1 (ICAM-1) expressed in the gut following traumatic brain injury (TBI). The aim of current study was to investigate the temporal pattern of intestinal NF-κB activation and ICAM-1 expression following TBI. METHODS: Male Wistar rats were randomly divided into six groups (6 rats in each group) including controls with sham operation and TBI groups at hours 3, 12, 24, and 72, and on d 7. Parietal brain contusion was adopted using weight-dropping method. All rats were decapitated at corresponding time point and mid-jejunum samples were taken. NF-KB binding activity in jejunal tissue was measured using EMSA. Immunohistochemistry was used for detection of ICAM-1 expression in jejunal samples. RESULTS: There was a very low NF-κB binding activity and little ICAM-1 expression in the gut of control rats after sham surgery. NF-KB binding activity in jejunum significantly increased by 160% at 3 h following TBI (P<0.05 vs control), peaked at 72 h (500% increase) and remained elevated on d 7 post-injury by 390% increase. Compared to controls, ICAM-1 was significantly up-regulated on the endothelia of microvessels in villous interstitium and lamina propria by 24 h following TBI and maximally expressed at 72 h post-injury (P<0.001). The endothelial ICAM-1 immunoreactivity in jejunal mucosa still remained strong on d 7 post-injury. The peak of NF-κB activation and endothelial ICAM-1 expression coincided in time with the period during which secondary mucosal injury of the gut was also at their culmination following TBI. CONCLUSION: TBI could induce an immediate and persistent up-regulation of NF-κB activity and subsequent up-regulation of ICAM-1 expression in the intestine. Inflammatory response mediated by increased NF-κB activation and ICAM-1 expression may play an important role in the pathogenesis of acute gut mucosal injury following TBI.展开更多
Locality preserving projection (LPP) is a newly emerging fault detection method which can discover local manifold structure of a data set to be analyzed, but its linear assumption may lead to monitoring performance de...Locality preserving projection (LPP) is a newly emerging fault detection method which can discover local manifold structure of a data set to be analyzed, but its linear assumption may lead to monitoring performance degradation for complicated nonlinear industrial processes. In this paper, an improved LPP method, referred to as sparse kernel locality preserving projection (SKLPP) is proposed for nonlinear process fault detection. Based on the LPP model, kernel trick is applied to construct nonlinear kernel model. Furthermore, for reducing the computational complexity of kernel model, feature samples selection technique is adopted to make the kernel LPP model sparse. Lastly, two monitoring statistics of SKLPP model are built to detect process faults. Simulations on a continuous stirred tank reactor (CSTR) system show that SKLPP is more effective than LPP in terms of fault detection performance.展开更多
A 3-D digital core describes the pore space microstructure of rocks. An X-ray micro CT scan is the most accurate and direct but costly method to obtain a 3-D digital core. In this study, we propose a hybrid method whi...A 3-D digital core describes the pore space microstructure of rocks. An X-ray micro CT scan is the most accurate and direct but costly method to obtain a 3-D digital core. In this study, we propose a hybrid method which combines sedimentation simulation and simulated annealing (SA) method to generate 3-D digital cores based on 2-D images of rocks. The method starts with the sedimentation simulation to build a 3-D digital core, which is the initial configuration for the SA method. We update the initial digital core using the SA method to match the auto-correlation function of the 2-D rock image and eventually build the final 3-D digital core. Compared with the typical SA method, the hybrid method has significantly reduced the computation time. Local porosity theory is applied to quantitatively compare the reconstructed 3-D digital cores with the X-ray micro CT 3-D images. The results indicate that the 3-D digital cores reconstructed by the hybrid method have homogeneity and geometric connectivity similar to those of the X-ray micro CT image. The formation factors and permeabilities of the reconstructed 3-D digital cores are estimated using the finite element method (FEM) and lattice Boltzmann method (LBM), respectively. The simulated results are in good agreement with the experimental measurements. Comparison of the simulation results suggests that the digital cores reconstructed by the hybrid method more closely reflect the true transport properties than the typical SA method alone.展开更多
To improve the separation performance of a supersonic gas separation device for the treatment of gas mixture with a single heavy component, a novel structure with shorter settlement distance was constructed and a meth...To improve the separation performance of a supersonic gas separation device for the treatment of gas mixture with a single heavy component, a novel structure with shorter settlement distance was constructed and a method of droplet enlargement was applied. A series of experiments were carried out in the improved separation device under various conditions, using air-ethanol vapor as the medium and micro water droplets as nucleation cen- ters. The effects of the inlet pressure, temperature and relative humidity, the swirling intensity, and mass flow rate of water on the separation performance were investigated. The separation was improved by increasing the inlet pressure and relative humidity. With the decrease of swirling intensity and mass flow rate of water, the separation efficiency increased first and then decreased. The inlet temperature had a slight effect on the separation. The results showed that the separation performance was effectively improved using the proposed structure and method, and the best separation in this study was obtained with the ethanol removal rate about 55% and dew point depression 27 K. The addition of water had little pollution to the air-ethanol vapor system since the water carry-over rate was within the range of -2 %-0 in most cases.展开更多
Transforming growth factor-β (TGF-β) signaling is tightly regulated to ensure its proper physiological functions in different cells and tissues. Like other cell surface receptors, TGF-β receptors are internalized...Transforming growth factor-β (TGF-β) signaling is tightly regulated to ensure its proper physiological functions in different cells and tissues. Like other cell surface receptors, TGF-β receptors are internalized into the cell, and this process plays an important regulatory role in TGF-β signaling. It is well documented that TGF-β receptors are endocytosed via clathrin-coated vesicles as TGF-β endocytosis can be blocked by potassium depletion and the GTPasedeficient dynamin K44A mutant. TGF-β receptors may also enter cells via cholesterol-rich membrane microdomain lipid rafts/caveolae and are found in caveolin-l-positive vesicles. Although receptor endocytosis is not essential for TGF-β signaling, clathrin-mediated endocytosis has been shown to promote TGF-β-induced Smad activation and transcriptional responses. Lipid rafts/caveolae are widely regarded as signaling centers for G protein-coupled recep- tors and tyrosine kinase receptors, but they are indicated to facilitate the degradation of TGF-β receptors and there- fore turnoff of TGF-β signaling. This review summarizes current understanding of TGF-β receptor endocytosis, the possible mechanisms underlying this process, and the role of endocytosis in modulation of TGF-β signaling.展开更多
Although there exist a few good schemes to protect the kernel hooks of operating systems, attackers are still able to circumvent existing defense mechanisms with spurious context infonmtion. To address this challenge,...Although there exist a few good schemes to protect the kernel hooks of operating systems, attackers are still able to circumvent existing defense mechanisms with spurious context infonmtion. To address this challenge, this paper proposes a framework, called HooklMA, to detect compromised kernel hooks by using hardware debugging features. The key contribution of the work is that context information is captured from hardware instead of from relatively vulnerable kernel data. Using commodity hardware, a proof-of-concept pro- totype system of HooklMA has been developed. This prototype handles 3 082 dynamic control-flow transfers with related hooks in the kernel space. Experiments show that HooklMA is capable of detecting compomised kernel hooks caused by kernel rootkits. Performance evaluations with UnixBench indicate that runtirre overhead introduced by HooklMA is about 21.5%.展开更多
We have previously reported that the human ACAT1 gene produces a chimeric mRNA through the interchromosomal processing of two discontinuous RNAs transcribed from chromosomes 1 and 7. The chimeric mRNA uses AUG1397-139...We have previously reported that the human ACAT1 gene produces a chimeric mRNA through the interchromosomal processing of two discontinuous RNAs transcribed from chromosomes 1 and 7. The chimeric mRNA uses AUG1397-1399 and GGC1274-1276 as translation initiation codons to produce normal 50-kDa ACAT1 and a novel enzymatically active 56-kDa isoform, respectively, with the latter being authentically present in human cells, including human monocyte- derived macrophages. In this work, we report that RNA secondary structures located in the vicinity of the GGC1274-1276 codon are required for production of the 56-kDa isoform. The effects of the three predicted stem-loops (nt 1255-1268, 1286-1342 and 1355-1384) were tested individually by transfecting expression plasmids into cells that contained the wild-type, deleted or mutant stem-loop sequences linked to a partial ACAT1 AUG open reading frame (ORF) or to the ORFs of other genes. The expression patterns were monitored by western blot analyses. We found that the upstream stem-loop1255-1268 from chromosome 7 and downstream stem-loop1286-1342 from chromosome 1 were needed for production of the 56-kDa isoform, whereas the last stem-loop135s-1384 from chromosome 1 was dispensable. The results of experi- ments using both monocistronic and bicistronic vectors with a stable hairpin showed that translation initiation from the GGC1274-1276 codon was mediated by an internal ribosome entry site (IRES). Further experiments revealed that translation initiation from the GGC1274-1276 codon requires the upstream AU-constituted RNA secondary structure and the downstream GC-rich structure. This mechanistic work provides further support for the biological significance of the chimeric nature of the human ACAT1 transcript.展开更多
It is a challenge to verify integrity of dynamic control flows due to their dynamic and volatile nature. To meet the challenge, existing solutions usually implant an "attachment" in each control transfer. However, t...It is a challenge to verify integrity of dynamic control flows due to their dynamic and volatile nature. To meet the challenge, existing solutions usually implant an "attachment" in each control transfer. However, the attachment introduces additional cost except performance penalty. For example, the attachment must be unique or restrictedly modified. In this paper, we propose a novel approach to detect integrity of dynamic control flows by counting executed branch instructions without involving any attachment. Our solution is based on the following observation. If a control flow is compromised, the number of executed branch instructions will be abnormally increased. The cause is that intruders usually hijack control flows for malicious execution which absolutely introduces additional branch instructions. Inspired by the above observation, in this paper, we devise a novel system named DCFI- Checker, which detect integrity corruption of dynamic control flows with the support of Performance Monitoring Counter (PMC). We have developed a proof-of-concept prototype system of DCFI-Checker on Linux fedora 5. Our experiments with existing kemel rootkits and buffer overflow attack show that DCFI- Checker is effective to detect compromised dynamic control transfer, and performance evaluations indicate that performance penaltyinduced by DCFI-Checker is acceptable.展开更多
Cleavage of chromosomal DNA into oligonucleosomal size fragments is an integral part of apoptosis. Elegant biochemical work identified the DNA fragmentation factor (DFF) as a major apoptotic endonuclease for DNA fragm...Cleavage of chromosomal DNA into oligonucleosomal size fragments is an integral part of apoptosis. Elegant biochemical work identified the DNA fragmentation factor (DFF) as a major apoptotic endonuclease for DNA fragmentation in vitro. Genetic studies in mice support the importance of DFF in DNA fragmentation and possibly in apoptosis in vivo. Recent work also suggests the existence of additional endonucleases for DNA degradation. Understanding the roles of individual endonucleases in apoptosis, and how they might coordinate to degrade DNA in different tissues during normal development and homeostasis, as well as in various diseased states, will be a major research focus in the near future.展开更多
A novel kernel learning method for object-oriented (00) software fault prediction is proposed in this paper. With this method, each set of classes that has inheritance relation named class hierarchy, is treated as a...A novel kernel learning method for object-oriented (00) software fault prediction is proposed in this paper. With this method, each set of classes that has inheritance relation named class hierarchy, is treated as an elemental software model. A layered kernel is introduced to handle the tree data structure corresponding to the class hierarchy models. This method was vali- dated using both an artificial dataset and a case of industrial software from the optical communication field. Preliminary experi- ments showed that our approach is very effective in learning structured data and outperforms the traditional support vector learning methods in accurately and correctly predicting the fault-prone class hierarchy model in real-life OO software.展开更多
文摘Objectives To identify the 5'untranslated region of Zika virus(ZIKV 5'UTR)RNA-binding proteins and to investigate the impact of the binding protein on the activity of internal ribosomal entry site(IRES)located in ZIKV 5'UTR and virus production.Methods Interacting proteins in U251 cells were captured using tRSA-tagged ZIKV 5'UTR RNA and tRSA-ZIKV 5'UTR RNA-binding proteins were visualized by SDS-PAGE silver staining,Subsequently,liquid chromatographytandem mass spectrometry(LC-MS/MS),bioinformatics analysis,and Western blot were used to identify the candidate proteins binding to ZIKV 5'UTR.Dicistronic expression assay and plaque forming assay were performed to analyze the effect of the binding protein on ZIKV IRES activity and ZIKV production,respecitvely.Results tRSA RNA pull-down assay,LC-MS/MS,and Western blot analysis showed that polypyrimidine tractbinding protein(PTB)bound to the ZIKV 5'UTR.Furthermore,dual luciferase reporter assay revealed that overexpression of PTB significantly enhanced the IRES activity of ZIKV(t=10.220,P<0.001),while PTB knockdown had the opposite effect(t=4.897,P<0.01).Additionally,virus plaque forming assay demonstrated that up-regulation of PTB expression significantly enhanced viral titer(t=6.400,P<0.01),whereas reducing PTB expression level weakened virus infectivity(t=5.055,P<0.01).Conclusion PTB positively interacts with the ZIKV 5'UTR and enhances IRES activity and virus production.
文摘Objective To study the central role of ginkgolide B (BN52021) in regulating cardiovascular function of nerve center by examining the effects of ginkgolide B on the electrical activity of rat paraventricular nucleus (PVN) neurons in hypothalamic slice preparation and to elucidate the mechanism involved. Methods Extracellular single-unit discharge recording technique. Results (1) In response to the application of ginkgolide t3 (0.1, 1, 10 μmol/L; n = 27) into the perfusate for 2 rain, the spontaneous discharge rates (SDR) of 26 (26/27, 96.30%) neurons were significantly decreased in a dose-dependent manner. (2) Pretreatment with L-glutamate (L-Glu, 0.2 mmol/L) led to a marked increase in the SDR of all 8 (100%) neurons in an epileptiform pattern. The increased discharges were suppressed significantly after ginkgolide B (1 μmol/L) was applied into the perfusate for 2 min. (3) In 8 neurons, perfusion of the selective L-type calcium channel agonist, Bay K 8644 (0.1 μmol/L), induced a significant increase in the discharge rates of 8 (8/8, 100%) neurons, while ginkgolide B (1μmol/L) applied into the perfusate, could inhibit the discharges of 8 (100%) neurons. (4) In 8 neurons, the broad potassium channels blocker, tetraethylammonium (TEA, 1 mmol/L) completely blocked the inhibitory effect of ginkgolide B (1 μmol/L). Conclusion These results suggest that ginkgolide B can inhibit the electrical activity of paraventricular neurons. The inhibitory effect may be related to the blockade of L-type voltage-activated calcium channel and potentially concerned with delayed rectifier potassium channel (KDR).
基金Supported by Based on Cuttingedge technology and research Project of Henan Province(072300430060)The focus of Scientific andTechnological Project of Henan Province(072102130023)Colleges and Universities of Henan Province in Support of TechnologicalInnovation Plan~~
文摘[ Objective] The aim of this study was to investigate the construction and identification of siRNA expression vector targeting nucleocapsid protein N gone of PRRSV. [Method] Three siRNA oligonucleotides targeting nucleocapsid protein N gone sequence of PRRSV were designed or synthesized, and then inserted into CMV promoter downstream to clone into pSilencer 4,1 -CMV eukaryotic expression vector. The recombinant expression vector was identified by enzyme digestion and DNA sequencing. [ Result] The results showed that the siRNA interference recombinant plasmid vector pSilencer-N targeting nucleocapsid protein gone expression had been successfully constructed. [ Conclusion] This study lays a foundation for studies on the controlling PRRSV by RNA interference technique .
基金This work was supported by the National High Technology Research and Development Program of China(863 Program)(No.2001 AA213081).
文摘The aim of this work was to improve the rate of conventionally blind enucleation for bovine somatic cell nuclear transfer. The cross section of a 0.5 ml Eppendorf tube was attached with a sheet of 400 mesh/inch2-cell screen after the bottom of the Eppendorf tube had been cut, and put into a 1 mL Eppendorf tube. In experiment 1, the oocytes in the metaphase Ⅱ stage were placed on the membrane in the Eppendorf tube, and centrifuged at 1,000, 2,000, or 3,000 r/min for 10 min, respectively. The oocytes were stained with Hoechst 33342 and then the relative position of the first polar body to the chromosomes, and the efficiency of enucleation were evaluated. In experiment 2, enucleated oocytes were fused with granulosa cells, following centrifugation and enucleation, and the potential development of the reconstituted embryos was estimated. The results indicated that the rate of enucleation in oocytes after centrifugation at 2,000 r/min for 10 min was 86.6% with an angle less then 20° between the first polar body and chromosomes. The rate of enucleation in cells spun at 2,000 r/min was higher than that of controls (87.4% vs. 64.4%, P 〈 0.05). Fur- thermore; centrifugation of recipient oocytes did not have a detrimental effect on the development of reconstituted embryos following nuclear transfer. In conclusion, centrifugation assisted enucleation may significantly improve the rate of bovine oocyte enucleation.
基金Supported by National Natural Science Foundation of China(30860201)~~
文摘[ Objective] This study was to investigate the effect of VEGF and its receptor Fit-1 mRNA expression in Mongolia sheep umbilical vein endothelial cells by ghrelin antisense inhibition. [ Method] Experiments were divided into 4 groups: group Ⅰ (blank control group) ; group Ⅱ (liposome group) ; group Ⅲ (SCON group: 20 μmol/L sense oligonucleotide) ; group Ⅳ (ASCON: 20 μmol/L antisense oligonucleotide). VEGF and its receptor Fit-1 mRNA expression changes were detected by using real-time fluorescence quantitative detection after 24, 36 and 48 h. [ Result] The expression of VEGF mRNA in group Ⅰ, group Ⅱ were insignificantly different at higher expression levels, and did not change significantly with the time; the expression of VEGF mRNA in group Ⅲ assumed a slight decrease, but there were no significant differences between group I and group Ⅱ (P 〉0.05), the expression of VEGF mRNA in group Ⅳ(antisense oligonucleotide group ) decreased significantly (P 〈 0.05) ; the expression of VEGF receptor FLT-1 mRNA was similar to that of VEGF. [ Conclusion] Antisense inhibition ghrelin has a downward effect to the expression of VEGF and its receptor Fit-1 the mRNA.
基金Supported by Scientific Research Foundation of the Chinese PLA Key Medical Programs During the 10th Five-Year Plan Period, No. 01Z011
文摘AIM: Nuclear factor kappa B (NF-κB) regulates a large number of genes involved in the inflammatory response to critical illnesses, but it is not known if and how NF-KB is activated and intercellular adhesion molecule-1 (ICAM-1) expressed in the gut following traumatic brain injury (TBI). The aim of current study was to investigate the temporal pattern of intestinal NF-κB activation and ICAM-1 expression following TBI. METHODS: Male Wistar rats were randomly divided into six groups (6 rats in each group) including controls with sham operation and TBI groups at hours 3, 12, 24, and 72, and on d 7. Parietal brain contusion was adopted using weight-dropping method. All rats were decapitated at corresponding time point and mid-jejunum samples were taken. NF-KB binding activity in jejunal tissue was measured using EMSA. Immunohistochemistry was used for detection of ICAM-1 expression in jejunal samples. RESULTS: There was a very low NF-κB binding activity and little ICAM-1 expression in the gut of control rats after sham surgery. NF-KB binding activity in jejunum significantly increased by 160% at 3 h following TBI (P<0.05 vs control), peaked at 72 h (500% increase) and remained elevated on d 7 post-injury by 390% increase. Compared to controls, ICAM-1 was significantly up-regulated on the endothelia of microvessels in villous interstitium and lamina propria by 24 h following TBI and maximally expressed at 72 h post-injury (P<0.001). The endothelial ICAM-1 immunoreactivity in jejunal mucosa still remained strong on d 7 post-injury. The peak of NF-κB activation and endothelial ICAM-1 expression coincided in time with the period during which secondary mucosal injury of the gut was also at their culmination following TBI. CONCLUSION: TBI could induce an immediate and persistent up-regulation of NF-κB activity and subsequent up-regulation of ICAM-1 expression in the intestine. Inflammatory response mediated by increased NF-κB activation and ICAM-1 expression may play an important role in the pathogenesis of acute gut mucosal injury following TBI.
基金Supported by the National Natural Science Foundation of China (61273160), the Natural Science Foundation of Shandong Province of China (ZR2011FM014) and the Fundamental Research Funds for the Central Universities (10CX04046A).
文摘Locality preserving projection (LPP) is a newly emerging fault detection method which can discover local manifold structure of a data set to be analyzed, but its linear assumption may lead to monitoring performance degradation for complicated nonlinear industrial processes. In this paper, an improved LPP method, referred to as sparse kernel locality preserving projection (SKLPP) is proposed for nonlinear process fault detection. Based on the LPP model, kernel trick is applied to construct nonlinear kernel model. Furthermore, for reducing the computational complexity of kernel model, feature samples selection technique is adopted to make the kernel LPP model sparse. Lastly, two monitoring statistics of SKLPP model are built to detect process faults. Simulations on a continuous stirred tank reactor (CSTR) system show that SKLPP is more effective than LPP in terms of fault detection performance.
基金sponsored by NSFC(Grant No.40574030)CNPC Research Project(Grant No.06A30102)
文摘A 3-D digital core describes the pore space microstructure of rocks. An X-ray micro CT scan is the most accurate and direct but costly method to obtain a 3-D digital core. In this study, we propose a hybrid method which combines sedimentation simulation and simulated annealing (SA) method to generate 3-D digital cores based on 2-D images of rocks. The method starts with the sedimentation simulation to build a 3-D digital core, which is the initial configuration for the SA method. We update the initial digital core using the SA method to match the auto-correlation function of the 2-D rock image and eventually build the final 3-D digital core. Compared with the typical SA method, the hybrid method has significantly reduced the computation time. Local porosity theory is applied to quantitatively compare the reconstructed 3-D digital cores with the X-ray micro CT 3-D images. The results indicate that the 3-D digital cores reconstructed by the hybrid method have homogeneity and geometric connectivity similar to those of the X-ray micro CT image. The formation factors and permeabilities of the reconstructed 3-D digital cores are estimated using the finite element method (FEM) and lattice Boltzmann method (LBM), respectively. The simulated results are in good agreement with the experimental measurements. Comparison of the simulation results suggests that the digital cores reconstructed by the hybrid method more closely reflect the true transport properties than the typical SA method alone.
基金Supported by the Natural Science Foundation of Liaoning Province, China (20052193) and Ph.D. Programs Foundation of Ministry of Education o f China (20070141045).
文摘To improve the separation performance of a supersonic gas separation device for the treatment of gas mixture with a single heavy component, a novel structure with shorter settlement distance was constructed and a method of droplet enlargement was applied. A series of experiments were carried out in the improved separation device under various conditions, using air-ethanol vapor as the medium and micro water droplets as nucleation cen- ters. The effects of the inlet pressure, temperature and relative humidity, the swirling intensity, and mass flow rate of water on the separation performance were investigated. The separation was improved by increasing the inlet pressure and relative humidity. With the decrease of swirling intensity and mass flow rate of water, the separation efficiency increased first and then decreased. The inlet temperature had a slight effect on the separation. The results showed that the separation performance was effectively improved using the proposed structure and method, and the best separation in this study was obtained with the ethanol removal rate about 55% and dew point depression 27 K. The addition of water had little pollution to the air-ethanol vapor system since the water carry-over rate was within the range of -2 %-0 in most cases.
基金The work in Ye-Guang Chen's laboratory is supported by grants from the National Natural Science Foundation of China (30430360, 30671033) and the Ministry of Sciences and Technology of China 973 Program (2004CB720002, 2006CB943401, 2006CB910102) and 863 Program (2006AA02Z 172).
文摘Transforming growth factor-β (TGF-β) signaling is tightly regulated to ensure its proper physiological functions in different cells and tissues. Like other cell surface receptors, TGF-β receptors are internalized into the cell, and this process plays an important regulatory role in TGF-β signaling. It is well documented that TGF-β receptors are endocytosed via clathrin-coated vesicles as TGF-β endocytosis can be blocked by potassium depletion and the GTPasedeficient dynamin K44A mutant. TGF-β receptors may also enter cells via cholesterol-rich membrane microdomain lipid rafts/caveolae and are found in caveolin-l-positive vesicles. Although receptor endocytosis is not essential for TGF-β signaling, clathrin-mediated endocytosis has been shown to promote TGF-β-induced Smad activation and transcriptional responses. Lipid rafts/caveolae are widely regarded as signaling centers for G protein-coupled recep- tors and tyrosine kinase receptors, but they are indicated to facilitate the degradation of TGF-β receptors and there- fore turnoff of TGF-β signaling. This review summarizes current understanding of TGF-β receptor endocytosis, the possible mechanisms underlying this process, and the role of endocytosis in modulation of TGF-β signaling.
基金The authors would like to thank the anonymous reviewers for their insightful corrnlents that have helped improve the presentation of this paper. The work was supported partially by the National Natural Science Foundation of China under Grants No. 61070192, No.91018008, No. 61170240 the National High-Tech Research Development Program of China under Grant No. 2007AA01ZA14 the Natural Science Foundation of Beijing un- der Grant No. 4122041.
文摘Although there exist a few good schemes to protect the kernel hooks of operating systems, attackers are still able to circumvent existing defense mechanisms with spurious context infonmtion. To address this challenge, this paper proposes a framework, called HooklMA, to detect compromised kernel hooks by using hardware debugging features. The key contribution of the work is that context information is captured from hardware instead of from relatively vulnerable kernel data. Using commodity hardware, a proof-of-concept pro- totype system of HooklMA has been developed. This prototype handles 3 082 dynamic control-flow transfers with related hooks in the kernel space. Experiments show that HooklMA is capable of detecting compomised kernel hooks caused by kernel rootkits. Performance evaluations with UnixBench indicate that runtirre overhead introduced by HooklMA is about 21.5%.
文摘We have previously reported that the human ACAT1 gene produces a chimeric mRNA through the interchromosomal processing of two discontinuous RNAs transcribed from chromosomes 1 and 7. The chimeric mRNA uses AUG1397-1399 and GGC1274-1276 as translation initiation codons to produce normal 50-kDa ACAT1 and a novel enzymatically active 56-kDa isoform, respectively, with the latter being authentically present in human cells, including human monocyte- derived macrophages. In this work, we report that RNA secondary structures located in the vicinity of the GGC1274-1276 codon are required for production of the 56-kDa isoform. The effects of the three predicted stem-loops (nt 1255-1268, 1286-1342 and 1355-1384) were tested individually by transfecting expression plasmids into cells that contained the wild-type, deleted or mutant stem-loop sequences linked to a partial ACAT1 AUG open reading frame (ORF) or to the ORFs of other genes. The expression patterns were monitored by western blot analyses. We found that the upstream stem-loop1255-1268 from chromosome 7 and downstream stem-loop1286-1342 from chromosome 1 were needed for production of the 56-kDa isoform, whereas the last stem-loop135s-1384 from chromosome 1 was dispensable. The results of experi- ments using both monocistronic and bicistronic vectors with a stable hairpin showed that translation initiation from the GGC1274-1276 codon was mediated by an internal ribosome entry site (IRES). Further experiments revealed that translation initiation from the GGC1274-1276 codon requires the upstream AU-constituted RNA secondary structure and the downstream GC-rich structure. This mechanistic work provides further support for the biological significance of the chimeric nature of the human ACAT1 transcript.
基金The work is supported in part by the National Natural Science Foundation of China,Natural Science Foundation of Beijing,National 863 High-Tech Research Development Program of China
文摘It is a challenge to verify integrity of dynamic control flows due to their dynamic and volatile nature. To meet the challenge, existing solutions usually implant an "attachment" in each control transfer. However, the attachment introduces additional cost except performance penalty. For example, the attachment must be unique or restrictedly modified. In this paper, we propose a novel approach to detect integrity of dynamic control flows by counting executed branch instructions without involving any attachment. Our solution is based on the following observation. If a control flow is compromised, the number of executed branch instructions will be abnormally increased. The cause is that intruders usually hijack control flows for malicious execution which absolutely introduces additional branch instructions. Inspired by the above observation, in this paper, we devise a novel system named DCFI- Checker, which detect integrity corruption of dynamic control flows with the support of Performance Monitoring Counter (PMC). We have developed a proof-of-concept prototype system of DCFI-Checker on Linux fedora 5. Our experiments with existing kemel rootkits and buffer overflow attack show that DCFI- Checker is effective to detect compromised dynamic control transfer, and performance evaluations indicate that performance penaltyinduced by DCFI-Checker is acceptable.
基金NIDA (DAll284). M. X. is a National Alliance for Research on Schizophrenia and Depression investigator and issupported by NI
文摘Cleavage of chromosomal DNA into oligonucleosomal size fragments is an integral part of apoptosis. Elegant biochemical work identified the DNA fragmentation factor (DFF) as a major apoptotic endonuclease for DNA fragmentation in vitro. Genetic studies in mice support the importance of DFF in DNA fragmentation and possibly in apoptosis in vivo. Recent work also suggests the existence of additional endonucleases for DNA degradation. Understanding the roles of individual endonucleases in apoptosis, and how they might coordinate to degrade DNA in different tissues during normal development and homeostasis, as well as in various diseased states, will be a major research focus in the near future.
文摘A novel kernel learning method for object-oriented (00) software fault prediction is proposed in this paper. With this method, each set of classes that has inheritance relation named class hierarchy, is treated as an elemental software model. A layered kernel is introduced to handle the tree data structure corresponding to the class hierarchy models. This method was vali- dated using both an artificial dataset and a case of industrial software from the optical communication field. Preliminary experi- ments showed that our approach is very effective in learning structured data and outperforms the traditional support vector learning methods in accurately and correctly predicting the fault-prone class hierarchy model in real-life OO software.