Master crack types and typical acoustic emission characteristics during rock failure

Acoustic emission(AE)signals contain substantial information about the internal fracture characteristics of rocks and are useful for revealing the laws governing the release of energy stored therein.Reported here is the evolution of rock failure with diferent master crack types as investigated using Brazilian splitting tests(BSTs),direct shear tests(DSTs),and uniaxial compression tests(UCTs).The AE parameters and typical modes of each fracture type were obtained,and the energy release characteristics of each fracture mechanism were discussed.From the observed changes in the AE parameters,the rock fracture process exhibits characteristics of staged intensifcation.The scale and energy level of crack activity in the BSTs were signifcantly lower than those in the DSTs and UCTs.The proportion of tensile cracks in the BSTs was 65%–75%,while the proportions of shear cracks in the DSTs and UCTs were 75%–85%and 70%–75%,respectively.During the rock loading process under diferent conditions,failure was accompanied by an increased number of shear cracks.The amplitude,duration,and rise time of the AE signal from rock failure were larger when the failure was dominated by shear cracks rather than tensile ones,and most of the medium-and high-energy signals had medium to low frequencies.After calculating the proposed energy amplitude ratio,the energy release of shear cracks was found to exceed that of tensile cracks at the same fracture scale.

Finite-time Control of Linear Singular Systems with Parametric Uncertainties and Disturbances

The concept of finite-time stability for linear singular system is induced in this paper.Finite-time control problem is considered for linear singular systems with time-varying parametricuncertainties and exogenous disturbances. The disturbance satisfies a dynamical system with para-metric uncertainties. A su?cient condition is presented for robust finite-time stabilization via statefeedback. The condition is translated to a feasibility problem involving restricted linear matrix in-equalities (LMIs). A detailed solving method is proposed for the restricted linear matrix inequalities.Finally, an example is given to show the validity of the results.

Alteration of cyclin D1 in gastric carcinoma and its clinicopathologic significance

AIM: To detect the genetic alteration and abnormal expression of cyclin D1 in gastric carcinoma and investigate its clinicopathologic significance in advanced gastric carcinoma. METHODS: Proteins of cyclin D1 were detected by immunohistochemistry in 42 cases of advanced gastric carcinoma with their follow-up data available, 27 cases of early stage carcinoma, 21 cases of gastric adenoma, 22 cases of hyperplastic polyp and 20 cases of normal mucosa adjacent to adenocarcinomas. Genetic alteration of cyclin D1 was detected by Southern blot and expression of cyclin D1 mRNA was detected by PT-PCR in 42 cases of advanced gastric carcinoma. RESULTS: Cyclin D1 protein was not expressed in normal mucosa, hyperplastic polyp and gastric adenoma, while it was only positively expressed in gastric carcinoma. The expression rate of cyclin D1 protein in early stage gastric carcinoma, advanced gastric carcinoma and lymph node metastasis was 48.1%, 47.4% and 50.0%, respectively. The amplification of cyclin D1 gene was detected in 16.6% of advanced gastric carcinomas. The overexpression of cyclin D1 mRNA was detected in 40.5% of the samples. There was no significant correlation between cyclin D1 protein expression and age, lymph-node metastasis and histological grading in patients with advanced gastric carcinoma (x^2=0.038,0.059,0.241, P>0.05). Significant correlation was observed between the expression of cyclin D1 protein and the 5-year survival rate (x^2=3.92, P<0.05). CONCLUSION: Detection of cyclin D1 protein by immunohistochemistry may be useful in the diagnosis of early gastric carcinomas. Patients with positive expression of cyclin D1 protein tend to have a worse prognosis.

TIP30 regulates apoptosis-related genes in its apoptotic signal transduction pathway

AIM: To investigate the role of TIP30 in apoptotic signal pathway in hepatoblastoma cells and to provide a basis for TIP30 as a gene therapy candidate in the regression of hepatoblastoma cells.METHODS: Apoptosis of human hepatoblastoma cell lines HepG2 (p53 wild), Hep3B (p53 null) and PLC/RPF/5 (p53mutant) infected with Ad-TIP30 (bearing a wild type human Tip30 gene) were analyzed and p53, Bax and Bclxl expression levels were compared among these cells.MlT assay, DNA fragmentation, in situ 3' end labeling of DNA, annexin-Ⅴ FITC staining were used to detect cell death and apoptosis in cells at various time intervals subsequent to infection, and to determine whether TIP30 had an effect on the expression levels of some apoptosis-related gene products such as Bax, p53 and Bcl-xl. A similar time course experiment was performed by Western blotting.RESULTS: In MTT assay, the viability of HepG2 cells decreased significantly from 99.7% to 10% and displayed more massive cell death within 5-8 d than Hep3B and PLC/RPF/5 cells, with their viability decreased from 97.8% to 44.3% and 98.1% to 50.4%, respectively. In annexin-ⅤFITC assay, the percentage of apoptosis cells in HepG2cells was two to three-fold higher than that in control cells (infected with Ad-GFP), two-fold higher than that in Hep3B cells and 1.4-fold higher than that in PLC/RPF/5 cells 36 h after infection, respectively. Moreover, in HepG2 cells, the p53 began to increase 6-8 h after infection, reaching a maximum level between 8 and 12 h after infection and then dropped. Bax showed a similar increase in the cells as p53 reached the maximum at 8-12 h and subsequently decreased. Interestingly, Bcl-xl protein levels were down regulated during 24 to 36 h after Ad-TIP30 infection. In contrast, ectopic expression of TIP30 in Hep3B and PLC/RPF/5 cells had no effect on the regulation of Bax expression, but had an effect on Bcl-xl levels. In comparison with HepG2 cells, these data suggested that up-regulation of p53 levels by TIP30 might be a pre-requisite for Bax and Bax/Bcl-xl ratio increase. We hypothesized that TIP30 might regulate Bax gene partly through p53, which sensitizes cells to apoptosis by involving a p53 apoptosis signal transduction pathway.CONCLUSION: TIP30 plays an important role in predisposing hepatoblastoma cells to apoptosis through regulating expression levels of these genes. Ad-TIP30carrying exogenous TIP30-anti-tumor genes may be regarded as a potential candidate for the treatment of hepatocellular carcinoma.

Clinical significance of plasma D-dimer and von Willebrand factor levels in patients with ulcer colitis

AIM: To investigate the levels of D-dimer(DD) and vonWillebrand factor(vWF) and the relationship between DDand vWF in ulcerative colitis(UC) patients.METHODS: A total of 29 plasma specimens were obtainedfrom patients with ulcerative colitis (male 13, female 16),aged 21-47 years (33 + 11). Disease activity was assessed byTruelove-Writeria. Patients with a score of above 5 wereregarded as having active colitis. Twenty healthy people(male 12, female 8),aged 19-53 years(31 + 14), ssrved asnormal controls. Blood samples were taken from anantecubital vein puncture. Blood(1.8 mL) was injected intothe tubes containing sodium citrate (0. 13 mmol/L). Theplasma was obtained by centrifugation at 3000 r@ min-1 for 10min, and stored at -80 ℃ until assayed by ELISA.RESULTS: The mean plasma levels of DD and vWF in activeUC patients were significantly higher than those of thecontrols(0.69+0.41 vs0.27+0.11, P＜0.01;143+46 vs103 + 35, P ＜ 0.01 ). The mean plasma levels of DD in thepatients with active disease were higher than those withinactive disease(0. 69 + 0. 41 vs 0.48+0.29, P＜0.05). Thelevls of v WF were not different between active and inactivepatients. DD levels were positively related to vWF levels( r =0.574, P ＜ 0. 01 ). There was no significant differencebetween levels of DD and vWF and the scope of disease cndsex of the patients.CONCLUSION: vWF is an important feature and a goodmarker of UC; intravascular thrombus and endothelial celldysfunction were found in UC patients; and the combinedtest of DD and vWF is helpful to distinguish the activity ofthe UC patients.

Protective effects of transplanted and mobilized bone marrow stem cells on mice with severe acute pancreatitis

AIM: To evaluate the protective effects of transplanted and mobilized bone marrow stem cells (BMSCs) on mice with severe acute pancreatitis (SAP) and to probe into their possible mechanisms.METHODS: A mouse model of SAP induced by intraparitoneal injections of L-arginine was employed in the present study.Two hundred female Balb/c mice weighing 18-22 g were randomly assigned into 4 groups. Group A was the stem cell mobilized group treated by injection of granulocytecolony stimulating factor (G-CSF) into mice for 4 days at a dose of 40 μg@kg-1@d-1 before induction of SAP. Group B was the group of BMSCs transplantation, in which the mice were given the isolated BMSCs via the tail vein 4 days prior to induction of SAP. Group C served as the model control and only SAP was induced. The mice without induction of SAP in group D acted as the normal control. At the time of animal sacrifice at 24, 48 and 72 h after induction of SAP, blood samples were obtained and prepared to detect serum amylase, while the abdominal viscera were examined both grossly and microscopically for the observation of pathological changes.RESULTS: The mortality of mice in the model control, groups A and B was 34%, 8% and 10% respectively within 72 h after induction of SAP. The serum level of amylase in the model control was significantly increased at all time points after induction of SAP as compared with that of the normal control (P＜0.05-0.01). When the mice were pretreated with BMSCs' transplantation or G-CSF injection, their serum level of amylase was significantly reduced at 48 h and 72 h after induction of SAP in comparison with that of the model control (P＜0.05-0.01). In accordance with these observations,both gross and microscopic examinations revealed that the pathological changes of SAP in mice pretreated with BMSCs transplantation or G-CSF injection were considerably attenuated as compared with those in the model control at all observed time points.CONCLUSION: Both transplanted allogenic and mobilized autologous BMSCs can protect mouse pancreas from severe damage in the process of SAP.

Aggregate formation of hepatitis B virus X protein affects cell cycle and apoptosis

AIM: To investigate whether the formation of aggregated HBx has a potential linking with its cellular responses.METHODS: Recombinant HBx was expressed in Escherichia coli and purified by Ni-NTA metal-affinity chromatography.Anti-HBx monoclonal antibody was developed for immunocytochemical detection. Bicistronic expression vector harboring full-length DNA of HBx was employed for transfection of human HepG2 ceils. Immunocytochemical staining was used to examine the intracellular HBx aggregates in cells. The effects of HBx aggregation on cell cycle and apoptosis were assessed by flow cytometry.RESULTS: Immunocytochemical staining revealed most of the HBx was formed intracellular aggregate in cytoplasm and frequently accumulated in large granules. Flow cytometry analysis showed that HepG2 cells transfected with vector harboring HBx significantly increased apoptosis and largely accumulated in the G0-G1 phase by maintenance in serum medium for 36 hours. Control cells without HBx aggregates in the presence of serum entered S phase and proliferated more rapidly at the same time.EGFP fluorescence in HBx expression cells was significantly decreased.CONCLUSION: Our observations show that cells with HBx aggregate undergo growth arrest and apoptosis, whereas control cells without HBx remain in growth and progression into S phase. Our data may provide helpful information to understand the biological effects of HBx aggregates on cells.

Natural organic matter(NOM) removal from surface water by coagulation

Poly aluminum chloride sulfate(PACS) with different SO 2- 4/Al 3+ mole ratios and bacicity(γ) of 2 0 was synthesized using AlCl 3\56H\-2O, Al\-2(SO\-4)\-3\518H 2O and Na 2CO 3 as raw materials. The effect of SO 2- \-4/Al 3+ ratio on the performance of PACS for removal of natural organic matter(NOM) with humic rich actual water was examined. It was found that PACS with SO 2- \-4/Al 3+ mole ratio of 0.0664 achieved the best NOM removal results and was selected to investigate its performance in comparison with PAC, FeCl 3 and alum(Al 2 (SO 4) 3·18H 2O). The experimental results showed that the optimum NOM removals were achieved at pH 5.0\_8.2 and the dose of about 5 0 mg/L as Al both for the selected PACS and PAC, at pH 5 0\_6 0 and the dose of about 7 0 mg/L as Fe for FeCl 3, and at pH 5 0\_7 0 and the dose of about 7 0 mg/L as Al for alum, respectively. At the optimum conditions, the selected PACS achieved the best NOM removal result, followed by PAC, FeCl 3, and then alum. The concentration of residual aluminum in treated water by the selected PACS and PAC under the optimum coagulant conditions was approximately 115 μg/L, which can completely comply with the regulated limits.

Cloning and expression of ornithine decarboxylase gene from human colorectal carcinoma

AIM: To construct and express ODC recombinant gene for further exploring its potential use in early diagnosis of colorectal carcinoma.METHODS: Total RNA was extracted from colon cancer tissues and amplified by reverse-transcription PCR with two primers, which span the whole coding region of ODC. The synthesized ODC cDNA was cloned into vector pQE-30 at restriction sites BamH I and Sal I which constituted recombinant expression plasmid pQE30-ODC. The sequence of inserted fragment was confirmed by DNA sequencing,the fusion protein including 6His-tag was facilitated for purification by Ni-NTA chromatographic column.RESULTS: ODC expression vector was constructed and confirmed with restriction enzyme digestion and subsequent DNA sequencing. The DNA sequence matching on NCBI Blast showed 99 % affinity. The vector was transformed into E.coli M15 and expressed. The expressed ODC protein was verified with Western blotting.CONCLUSION: The ODC prokaryote expression vector is constructed and thus greatly facilitates to study the role of ODC in colorectal carcinoma.

Intermediate fertile Triticum aestivum (+) Agropyron elongatum somatic hybrids are generated by low doses of UV irradiation

We report the production and characterization of somatic hybrids between Triticum aestivum L. and Agropyron elongatum (Host) Nevishi (the synonym is Thinopyrum ponticum). Asymmetric protoplast fusion was performed between Agropyron elongatum protoplasts irradiated with a low UV dose and protoplasts of wheat taken from nonregenerable suspension cultures. More than 40 green plantlets were obtained from 15 regenerated clones and one of them produced seeds. The phenotypes of the hybrid plants and seeds were intermediate between wheat and Agropyron elongatum. All of the regenerated calli and plants were verified as intergeneric hybrids on the basis of morphological observation and analysis of isozyme,cytological,5SrDNA spacer sequences and random amplified polymorphic DNA (RAPD). RFLP analysis of the mitochondrial genome revealed evidence of random segregation and recombination of mtDNA.

Imaging of Activity of Horseradish Peroxidase at β-Cyclodextrin Polymer by Scanning Electrochemical Microscopy

The activity of horseradish peroxidase at b-cyclodextrin polymer was imaged by scanning electrochemical microscopy using 3, 3', 5, 5'-tetramethylbenzide and H2O2 as the substrates.

Alterations in expression,proteolysis and intracellular localizations of clusterin in esophageal squamous cell carcinoma

AIM: To investigate biogenesis and intracellular Iocalizations of clusterin to elucidate the potential molecular mechanisms implicated in tumorigenesis of esophageal mucosa.METHODS: Semi-quantitative RT-PCR for multi-region alteration analysis, Western blot for different transcriptional forms and immunohistochemical staining for intracellular Iocalizations of clusterin were carried out in both tissues and cell lines of ESCC.RESULTS: The N-terminal deletions of the clusterin gene and the appearance of a 50-53 ku nuclear clusterin, an uncleaved, nonglycosylated, and disulfide-linked isoform,were the major alterations in cancer cells of esophagus.Naturally the 40 ku clusterin was located in the connective tissue of the lamina propria of epithelial mucosa and right under the basal membrane of epithelia, but it was disappeared in stromal mucosa of esophagus and the pre-matured clusterin was found positive in cancerous epithelia.CONCLUSION: The N-terminal deletion of clusterin may be essential for its alterations of biogenesis in ESCC.

CNC FLEXIBLE GENERATING SPECIFIC GEAR TOOTH PROFILE BASED ON STANDARD INVOLUTE GEAR HOB

A new method named orthogonal two-way link-shift here has been proposed.Based on the method and a standard involute gear hob, a specific gear tooth profile (including anarbitrary gear tooth profile and a modified involute gear tooth profile) can be generated on aCNC(computer numerical control) bobbing machine. Computer simulation has been carried out, and theresults prove that the method is right and practicable. So, the fabrication costs can be greatlydecreased than before. The new method has momentous significance to realize gear's optimizedmodification under different work conditions.

Studies on Manganese Peroxidase Immobilized in Gelatin-containing Microemulsion-based Gels

The immobilized technique of manganese peroxidase(MnP) in gelatin-containing microemulsion-based gels and the effects of storage time and reuse times on its catalytic activity were studied. The results show that the MnP immobilized together with Mn 2+ and H_2O_2 could effectively oxidize syringaldazine in n-heptane. The immobilized MnP still had a high catalytic activity after one-month storage under a freezing condition. The reuse times have a relation to the amount of the immobilized H_2O_2. When the amount of the immobilized H_2O_2 is sufficient, the microemulsion-based gels containing MnP could be used many times.

AFM Study on Interface of HTHP As-grown Diamond Single Crystal and Metallic Film

The study for the interface of as-grown diamond and metallic film surrounding diamond is an attractive way for understanding diamond growth mechanism at high temperature and high pressure (HTHP), because it is that through the interface carbon atom groups from the molten film are transported to growing diamond surface. It is of great interest to perform atomic force microscopy (AFM) experiment; which provides a unique technique different from that of normal optical and electron microscopy studies, to observe the interface morphology. In the present paper, we report first that the morphologies obtained by AFM on the film are similar to those of corresponding diamond surface, and they are the remaining traces after the carbon groups moving from the film to growing diamond. The fine particles and a terrace structure with homogeneous average step height are respectively found on the diamond (100) and (111) surface. Diamond growth conditions show that its growth rates and the temperature gradients in the boundary layer of the molten film at HTHP result in the differences of surface morphologies on diamond planes, being rough on (100) plane and even on the (111) plane. The diamond growth on the (100) surface at HPHT could be considered as a process of unification of these diamond fine particles or of carbon atom groups recombination on the growing diamond crystal surface. Successive growth layer steps directly suggest the layer growth mechanism of the diamond (111) plane. The sources of the layer steps might be two-dimensional nuclei and dislocations.

Androgen receptor isoforms in human and rat prostate

Aim: To investigate the androgen receptor (AR) isoforms and its variability of expression in human and rat prostatictissues. Methods: Human benign prostatic hyperplasia (BPH) and prostatic cancer tissues were obtained from pa-tients undergoing prostatectomy, and rat ventral prostate was incised 3 days after castration. Forty-one AR-positive BPHspecimens, 3 prostatic cancer specimens, and 6 rat prostates were used. After processing at 4℃, the tissues were ex-amined by means of high resolution isoelectric focusing (IEF) technique to determine their AR isoforms. Results:From the prostatic specimens, 3 types of AR isoforms were detected with pI values at 6.5, 6.0, and 5.3. In humanBPH tissues, 15/41 (36.6%) specimens showed all the three types of isoforms, while 19/41 (46.3%) showed 2 iso-fora at various combinations and 7/41 (17.1%), 1 isoform. For the 3 prostatic cancer specimens, one showed 3 iso-forms, one, 2 isoforms, and the other failed to show any isoform. All rat prostatic tissues showed 2 isoforms at differ-ent combinations. Binding of ~3H-dihydrotestosterone (DHT) to the isoforms was inhibited by the addition of 100-foldexcess of DHT or testosterone, but not progesterone, oestradiol or diethylstilboestrol. Conclusion: AR isoforms aredifferent in different patients. Although their genesis is not clear, the therapeutic implication of the present observationappears to be interesting, that may help clarifying the individual differences in the response to hormonal therapy.(Asian J Androl 2000 Dec; 2: 307-310)

Kinetics of the Esterification Reaction Catalyzed by Lipase in W/O Microemulsions of Alkyl Polyglucoside

A novel kinetic mechanism of esterification reaction of 1-hexanoic acid with 1-butanol, catalyzed by lipase, was studied in water-in-oil microemulsions. The microemulsions were formed by alkyl polyglucoside C10G1.54/1-butanol / cyclohexane/phosphate buffer solution. The result shows that when the ratio of mol concentration of 1-butanol to 1-hexanoic acid is about 3.0, the initial rate V0 get the maximum values. This phenomenon was explained by the modified fishlike phase diagrams.

Inhibitory effect of heparin-derived oligosaccharides on secretion of interleukin-4 and interleukin-5 from human peripheral blood T lymphocytes

AIM: To investigate the inhibitory effect of heparin-derived oligosaccharides (Oligs) on secretion of interleukin-4 (IL-4) and interleukin-5 (IL-5) from human peripheral blood T lymphocytes (PBTLs).METHODS: Oligs were prepared by three different heparin depolymerization methods and separated by gel filtration chromatography. PBTLs from ten adult patients with allergic eosinophilic gastroenteritis were treated with phytahematoagglutinin (PHA) and Oligs. The supernatants from the cell culture of PBTLs were harvested and subjected to the determination of IL-4 and IL-5 contents by ELISA method.RESULTS: At the concentration of 5μg/mL, Oligs with different Mr had different effects on the secretion of IL-4 and IL-5. The tetrasaccharide with Mr of 1 142, produced by depolymerizing heparin with hydrogen peroxide, had the strongest inhibitory effect on the secretion of IL-4. It decreased the IL-4 content from 375.6±39.2 ng/L (PHA group) to 12.5±5.7 ng/L (P<0.01). The hexasaccharide with Mr of I 806, produced by depolymerizing heparin with βelimination method, had the strongest inhibitory effect on the secretion of IL-5. It decreased the IL-5 content from 289.2±33.4 ng/L (PHA group) to 22.0±5.2 ng/L (P<0.01).CONCLUSION: The inhibitory activity of Oligs on the secretion of IL-4 and IL-5 from human PBTLs closely depends on their molecular structure, and there may be an essential structure to act as an inhibitor. The most effective inhibitors of IL-4 and IL-5 secretion are tetrasaccharides and hexasaccharides, respectively.

A New Pullulan-Producing Yeast and Medium Optimization for Its Exopolysaccharide Production

Yeast strain Y68 producing high level of pullulan was isolated from the phyton collected in Toulouse, France. This strain was identified to be Rhodotorula bacarum by BIOLOG analysis. This is the first report that pullulan was produced by Rhodotorula bacarum. The optimal medium (g L -1) for pullulan production by this strain was 80 glucose, 20 soybean cake hydrolysate, 5 K 2HPO 4, 1 NaCl, 0.2 MgSO 4·7H 2O, 0.6 (NH 4) 2SO 4, pH 7.0. Under this condition, 54 g L -1 pullulan was produced within 60 h at 30 ℃. Pullulan is a better starting material for producing marine prodrugs.

Downregulation of alpha-fetoprotein siRNA inhibits proliferation of SMMC-7721 cells

AIM: To study the function of α-fetoprotein (AFP) in SMMC-7721 hepatoma cells.METHODS: A hairpin siRNA expressing plasmid pSilencer3.0-H1-afp was constructed and transfected into SMMC-7721 cells with Lipofectamine 2000. The expression of AFP was monitored by real-time RT-PCR and immunoassays, its effect on SMMC-7721 cell proliferation and cell death was detected by MTT and fluorescenceactivated cell sorter (FACS).RESULTS: The AFP-siRNA expressing plasmid downregulated the expression of AFP obviously (about 34%), and inhibited SMMC-7721 cell proliferation, but did not induce apoptosis.CONCLUSION: Downregulation of AFP siRNA inhibits proliferation of SMMC-7721 cells, but cannot cause apoptosis.