快速回程液压缸的作用机理研究

文章主要分析和探讨了靠面积变速的液压缸快速回程的作用机理。

试谈昆曲艺术对苏州现当代文学创作的影响——以周瘦鹃创作作为考察中心

昆曲艺术对现当代吴地作家的文学创作,无论是显在影响还是潜在影响,都有着不言而喻的滋养作用,它哺育了一代又一代的苏州作家。本文主要以苏州现当代作家周瘦鹃作品为例,考察昆曲艺术对周瘦鹃文学创作的渗透作用。

An Improved Enucleation Method of Bovine Somatic Cell Nuclear Transfer

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.

MODELING METHOD FOR CROSSCUTTING CONCERNS IN CONCURRENT SOFTWARE SYSTEM

A method for modeling crosscutting concerns in the concurrent software system is presented based on the aspect-oriented（A-O） technique and the statechart of unified modeling language （UML）. Modeled with UML statechart diagrams, the primary system functions and corresponding traversal features are enveloped into various orthogonal regions of a composite state. The mutual relationships between orthogonal regions are implied by the orders of broadcast events. Using a modular transition system as a basic computational model, the formalization description of A-O statechart models is proposed. The precise semantics of model elements and modeling procedures is given. The example study indicates that the separation strategy of crosscutting concerns is implemented in the design phase of the concurrent software system with this method. Meanwhile, the software modeling method has advantages of loose coupling, adaptability and traceability.

Hepatic artery infusion with raltitrexed or 5-fluorouracil for colorectal cancer liver metastasis

AIM To evaluate the efficiency and safety of hepatic artery infusion chemotherapy(HAIC) using raltitrexed or 5-fluorouracil for colorectal cancer(CRC) liver metastasis(CRCLM).METHODS A retrospective analysis of patients with unresectable CRCLM who failed systemic chemotherapy and were subsequently treated with HAIC at our institute from May 2013 to April 2015 was performed. A total of 24 patients were treated with 5-fluorouracil, and 18 patients were treated with raltitrexed. RESULTS The median survival time(MST) from diagnosis of CRC was 40.8 mo in the oxaliplatin plus raltitrexed(TOMOX) arm and 33.5 mo in the oxaliplatin plus 5-fluorouracil(FOLFOX) arm(P = 0.802). MST from first HAIC was 20.6 mo in the TOMOX arm and 15.4 mo in the FOLFOX arm(P = 0.734). Median progression-free survival(PFS) from first HAIC was 4.9 mo and 6.6 mo, respectively, in the TOMOX arm and FOLFOX arm(P= 0.215). Leukopenia(P = 0.026) was more common in the FOLFOX arm, and hepatic disorder(P = 0.039) was more common in the TOMOX arm. There were no treatment-related deaths in the TOMOX arm and one treatment-related death in the FOLFOX arm. Analysis of prognostic factors indicated that response to HAIC was a significant factor related to survival.CONCLUSION No significant difference in survival was observed between the TOMOX and FOLFOX arms. HAIC treatment with either TOMOX or FOLFOX was demonstrated as an efficient and safe alternative choice.

The research progress and prospect for the technology of controlling surface subsidence by grouting separated layer in overburden at coal mines in China

The developed process and theoretical achievement for the technology of controlling surface subsidence by grouting separated layer in overburden is summarized in this paper. The research progress of the technology is discussed synthetically on the basis of practice and research results obtained at coal mine of China in recent years. According to the development tendency of mining under buildings, water bodies and railroads and the properties of the technology, the future research direction is proposed.

Science Letters:A novel way of liver preservation improves rat liver viability upon reperfusion

Background/aim： Currently, the liver is cold-preserved at 0-4 ℃ for experimental and clinical purposes. Here, we investigated whether milder hypothermia during the initial phase of the preservation period was beneficial for liver viability upon reperfusion. Methods： In the first set of experiments, rat livers were preserved either conventionally in clinically used histidine-trypthopan-ketoglutarate （HTK） solution （Group A： 45 min and Group B： 24 h） or by slow cooling HTK solution （from 13 ℃ to 3 ℃） during the initial 45 min of preservation （Group C： 24 h）. In the second set of experiments, additional groups of livers were evaluated： Group BB-preservation according to Group B and Group CC-preservation according to Group C. Further, some livers were preserved at 13 ℃ for 24 h. Livers were then reperfused using a blood-free perfusion model. Results： Bile production was approximately 2-fold greater in Group C compared to Group B. Alanine transaminase （ALT） and aspartate transaminase （AST） release into perfusate were 2-3-fold higher in Group B compared to Group C. No significant differences were found in ALT and AST release between Group C and Group A. Livers in Group CC compared to Group BB exhibited significantly lower portal resistance, greater oxygen consumption and bromosulfophthalein excretion into bile and lower lactate dehydrogenase （LDH） release into perfusate. Histological evaluation of tissue sections in Group BB showed parenchymal dystrophy of hepatocytes, while dystrophy ofhepatocytes was absent in Group CC. Livers preserved at 13 ℃ for 24 h exhibited severe ischemic injury Conclusion： These results suggest that the conventional way of liver preservation is not suitable at least for rat livers and that slow cooling of HTK solution during the initial phase of cold storage can improve liver viability during reperfusion.

Nuclear factor-KB decoy oligodeoxynucleotides attenuates ischemia/reperfusion injury in rat liver graft

AIM： To evaluate the protective effect of NF-kB decoy oligodeoxynucleotides （ODNs） on ischemia/reperfusion （I/R） injury in rat liver graft. METHODS： Orthotopic syngeneic rat liver transplantation was performed with 3 h of cold preservation of liver graft in University of Wisconsin solution containing phosphorothioated double-stranded NF-kB decoy ODNs or scrambled ODNs. NF-kB decoy ODNs or scrambled ODNs were injected intravenously into donor and recipient rats 6 and 1 h before operation, respectively. Recipients were killed 0 to 16 h after liver graft reperfusion. NF-kB activity in the liver graft was analyzed by electrophoretic mobility shift assay （EMSA）. Hepatic mRNA expression of TNF-α, IFN-γ and intercellular adhesion molecule-1 （ICAM-1） were determined by semiquantitative RT-PCR. Serum levels of TNF-α and IFN-γ were measured by enzyme-linked immunosorbent assays （ELISA）. Serum level of alanine transaminase （ALT） was measured using a diagnostic kit. Liver graft myeloperoxidase （MPO） content was assessed. RESULTS： NF-kB activation in liver graft was induced in a time-dependent manner, and NF-kB remained activated for 16 h after graft reperfusion. NF-kB activation in liver graft was significant at 2 to 8 h and slightly decreased at 16 h after graft reperfusion. Administration of NF-kB decoy ODNs significantly suppressed NF-kB activation as well as mRNA expression of TNF-α, IFN-γ, and ICAM-1 in the liver graft. The hepatic NF-kB DNA binding activity [presented as integral optical density （IOD） value] in the NF-kB decoy ODNs treatment group rat was significantly lower than that of the I/R group rat （2.16±0.78 vs 36.78 ±6.35 and 3.06±0.84 vs 47.62± 8.71 for IOD value after 4 and 8 h of reperfusion, respectively, P〈0.001）. The hepatic mRNA expression level of TNF-α, IFN-γ and ICAM-1 rpresented as percent of β-actin mRNA （%）] in the NF-kB decoy ODNs treatment group rat was significantly lower than that of the I/R group rat （8.31 ±3.48 vs 46.37±10.65 and 7.46± 3.72 vs 74.82±12.25 for hepatic TNF-α mRNA, 5.58±2.16 vs 50.46±9.35 and 6.47±2.53 vs 69.72±13.41 for hepatic IFN-γ mRNA, 6.79 ±2.83 vs 46.23±8.74 and 5.28±2.46 vs 67.44±10.12 for hepatic ICAM-1 mRNA expression after 4 and 8 h of reperfusion, respectively, P〈0.001）. Administration of NF-kB decoy ODNs almost completely abolished the increase of serum level of TNF-α and IFN-γ induced by hepatic ischemia/reperfusion, the serum level （pg/mL） of TNF-α and in the NF-kB decoy ODNs treatment group rat was significantly lower than that of the I/R group rat （42.7±13.6 vs 176.7±15.8 and 48.4±15.1 vs 216.8±17.6 for TNF-α level, 31.5±12.1 vs 102.1±14.5 and 40.2±13.5 vs 118.6±16.7 for IFN-γ level after 4 and 8 h of reperfusion, respectively, P〈0.001）. Liver graft neutrophil recruitment indicated by MPO content and hepatocellular injury indicated by serum ALT level were significantly reduced by NF-kB decoy ODNs, the hepatic MPO content （A655） and serum ALT level （IU/L） in the NF-kB decoy ODNs treatment group rat was significantly lower than that of the I/R group rat （0.17±0.07 vs 1.12±0.25 and 0.46±0.17 vs 1.46±0.32 for hepatic MPO content, 71.7±33.2 vs 286.1±49.6 and 84.3±39.7 vs 467.8±62.3 for ALT level after 4 and 8 h of reperfusion, respectively, P〈0.001）. CONCLUSION： The data suggest that NF-kB decoy ODNs protects against I/R injury in liver graft by suppressing NF-kB activation and subsequent expression of proinflammatory mediators.

Donation after cardio-circulatory death liver transplantation

The renewed interest in donation after cardio-circulatory death (DCD) started in the 1990s following the limited success of the transplant community to expand the donation after brain-death (DBD) organ supply and following the request of potential DCD families. Since then, DCD organ procurement and transplantation activities have rapidly expanded, particularly for nonvital organs, like kidneys. In liver transplantation (LT), DCD donors are a valuable organ source that helps to decrease the mortality rate on the waiting lists and to increase the availability of organs for transplantation despite a higher risk of early graft dysfunction, more frequent vascular and ischemia-type biliary lesions, higher rates of re-listing and re-transplantation and lower graft survival, which are obviously due to theinevitable warm ischemia occurring during the declaration of death and organ retrieval process. Experimental strategies intervening in both donors and recipients at different phases of the transplantation process have focused on the attenuation of ischemia-reperfusion injury and already gained encouraging results, and some of them have found their way from pre-clinical success into clinical reality. The future of DCD-LT is promising. Concerted efforts should concentrate on the identification of suitable donors (probably Maastricht category Ⅲ DCD donors), better donor and recipient matching (high risk donors to low risk recipients), use of advanced organ preservation techniques (oxygenated hypothermic machine perfusion, normothermic machine perfusion, venous systemic oxygen persufflation), and pharmacological modulation (probably a multi-factorial biologic modulation strategy) so that DCD liver allografts could be safely utilized and attain equivalent results as DBD-LT.

Gene expression profile in rat small intestinal allografts after cold preservation/reperfusion

AIM: To determine the changes of gene expression profile in small intestinal allografts in rats after cold preservation/ reperfusion, and to identify the genes relevant to cold preservation/reperfusion injury. METHODS: Heterotopic segmental small bowel transplantation was performed in six rats with a sham operation and they were used as controls. Total RNA was extracted from the allografts (experimental group) and normal intestines (control group) 1 h after cold preservation/ reperfusion, and then purified to mRNA, which was then reversely transcribed to cDNA, and labeled with fluorescent Cy5-dUTP and Cy3-dUTP to prepare hybridization probes. The mixed probes were hybridized to the cDNA microarray. After high-stringent washing, the fluorescent signals on cDNA microarray chip were scanned and analyzed. RESULTS: Among the 4 096 target genes, 82 differentially expressed genes were identified between the two groups. There were 18 novel genes, 33 expression sequence tags, and 31 previously reported genes. The selected genes may be divided into four classes: genes modulating cellular adhesion, genes regulating cellular energy, glucose and protein metabolism, early response genes and other genes. CONCLUSION: A total of 82 genes that may be relevant to cold preservation/reperfusion injury in small intestinal allografts are identified. Abnormal adhesion between polymorphonuclears and endothelia and failure in energy, glucose and protein metabolism of the grafts may contribute to preservation/reperfusion injury. The functions of the novel genes identified in our study need to be clarified further.

Protective effect of L-arginine preconditioning on ischemia and reperfusion injury associated with rat small bowel transplantation

AIM: To investigate the protective effect and possible mechanism of L-arginine preconditioning on ischemia and reperfusion injury associated with small bowel transplantation (SBT).METHODS: Male inbred Wistar rats weighting between 180 and 250 g were used as donors and recipients in thestudy. Heterotopic rat SBT was performed according to the techniques of Li and Wu. During the experiment, intestinal grafts were preserved in 4 ℃ Ringer's solution for 8 h before being transplanted. Animals were divided into three groups. In group 1, donors received intravenous L-arginine (50 mg/kg, 1 mL) injection 90 min before graft harvesting. However, donors in control group were given normal saline (NS) instead. In group 3, six rats were used as sham-operated control. Specimens were taken from intestinal grafts 15 min after reperfusion. Histological grading, tissue malondialdehyde (MDA) and myeloperoxidase (MPO) levels were assessed. The graft survival of each group was monitored daily until 14 d after transplantation. RESULTS: Levels of MDA and MPO in intestine of shamoperated rats were 2.0±0.22 mmol/g and 0.66±0.105 U/g. Eight hours of cold preservation followed by 15 min of reperfusion resulted in significant increases in tissue MDA and MPO levels. Pretreatment with L-arginine before graft harvesting resulted in lower enhancement of tissue levels of MDA and MPO and the differences were significant (4.71±1.02 mmol/g vs8.02±3.49 mmol/g, 1.03±0.095 U/g vs 1.53±0.068 U/g, P＜0.05). Besides, animals in L-arginine pretreated group had better histological structures and higher 2-wk graft survival rates comparing with that in NS treated group (3.3±0.52 vs6±0.1, 0/6 vs6/6, P＜0.05or 0.01).CONCLUSION: L-arginine preconditioning attenuates ischemia and reperfusion injury in the rat SBT model,which was due to antioxidant activities partially.

EXPERIMENTAL STUDY OF NERVE GRAFT WITH VASCULAR IMPLANTATION

Objective To study the performance of free nerve graft with vascular implantation Material and method Three groups of rats were used A 10 mm nerve defect was made in the sciatic nerve It was repaired respectively with vascularised nerve graft(VNG), free nerve graft with vascular implantation(NGV) or free nerve graft(NG) Before 30 days the revascularisation of the nerve graft was assessed;at 2 to 3 month regeneration of nerve was evaluated Histochemical staining, vascular morphology and electrophysiological examination were undertaken Result and conclusion The number of regenerated blood vessels in VNG and NGV was significantly increased than that in NG before 30 days The ratio of regenerated nerve fiber area and conduction velocity in the first two groups were much better than those in NG at 2 to 3 months

How to protect liver graft with nitric oxide

Organ preservation and ischemia reperfusion injury associated with liver transplantation play an important role in the induction of graft injury. One of the earliest events associated with the reperfusion injury is endothelial cell dysfunction. It is generally accepted that endothelial nitric oxide synthase （e-NOS） is cell-pro- tective by mediating vasodilatation, whereas inducible nitric oxide synthase mediates liver graft injury after transplantation. We conducted a critical review of the literature evaluating the potential applications of regulating and promoting e-NOS activity in liver preservation and transplantation, showing the most current evidence to support the concept that enhanced bioavailability of NO derived from e-NOS is detrimental to ameliorate graft liver preservation, as well as preventing subse- quent graft reperfusion injury. This review deals mainly with the beneficial effects of promoting ＂endogenous＂ pathways for NO generation, via e-NOS inducer drugs in cold preservation solution, surgical strategies such as ischemic preconditioning, and alternative ＂exogenous＂ pathways that focus on the enrichment of cold storage liquid with NO donors. Finally, we also provide a basic bench-to-bed side summary of the liver physiology and cell signalling mechanisms that account for explaining the e-NOS protective effects in liver preservation and transplantation.

Introducing aggregate into grouting material and its influence on load transfer of the rock bolting system

A fully grouted bolt provides greater shear load capacity for transmitting the load from the rock to the bolt, and vice versa. When grout fills irregularities between the bolt and the rock, a keying effect is created to transfer the load to the bolt via shear resistance at the interface and within the grout. Previous research has revealed that the mechanical properties of the grout had a great impact on the load transfer capacity of the rock bolting system. This paper presents a method to enhance the rock bolting strength by introducing metal granules into the grouting material. Experimental results suggest that both the average peak load of pullout tests and the total energy absorption of the system will increase if some metal granules are mixed into the resin.

INTERFERENCE CANCELLATION FOR MOBILE DISPERSIVE CHANNELS

A robust interference canceller for Multi-Carrier Code Division Multiple Access(MC-CDMA) using Orthogonal Frequency Division Multiplexing (OFDM) in Rayleigh fading isproposed. This interference canceller is robust in the sense that it cancels Inter-Carriers Inter-ference (ICI) and is suitable for use in dispersive channels. To come up the effects of the signaldispersion, Doppler shifts and delay spreads on the performance of MC-CDMA systems over mo-bile fading channels, this interference canceller exploits the merit of the orthogonal signaling andpilot signals to evaluate the channel parameters. This interface canceller is well suited to work initerative turbo interference cancellation.

Prediction of ground surface displacement caused by grouting

Ground surface displacement caused by grouting was calculated with stochastic medium theory. Ground surface displacement was assumed to be caused by the cavity expansion of grouting, slurry seepage, and slurry contraction. A prediction method of ground surface displacement was developed. The reliability of the presented method was validated through a comparison between theoretical results and results from engineering practice. Results show that the present method is effective. The effect of parameters on uplift displacement was illustrated under different grouting conditions. Through analysis, it can be known that the ground surface uplift is mainly caused by osmosis of slurry and the primary influence angle of stratum β determines the influence range of surface uplift. Besides, the results show that ground surface uplift displacement decreases notably with increasing depth of the grouting cavity but it increases with increasing diffusion radius of grout and increasing grouting pressure.

Studies of Selective Arterial Perfusion plus Chemoembolization on Hepatic Metastasis from Rectal Cancer

OBJECTIVE To develop an effectual method for treating hepatic metas-tasis from rectal cancer. METHODS A randomized control study of celiac artery perfusion plus transcatheter hepatic arterial chemoembolization (TACE) (observation group) and intravenous chemotherapy (control group) for 99 cases with hepatic me-tastasis from rectal cancer was performed. The perfusion was repeated once at 4 weeks after the first treatment of 52 cases in the observation group, and it was subsequently repeated at an interval of 2 or 3 months. Using intrave-nous administration, the perfusion was repeated once every 3 weeks with 47 cases in the control group. RESULTS Three months after treatment, the patients in the observation group who showed a relief or elimination of a former superior abdominal pain amounted to 70.6%, and those with a diminution of their intrahepatic mass reached 55.8%. In the control group, the patients with a relief or disappear-ance of hepatalgia reached 20%, and those with a diminution of their intrahe-patic mass reached 10.6%. The 1, 2 and 3-year survival rates were 80.8%, 46.2% and 25.0% in the cases of the observation group and 61.7%, 19.1% and 4.3% in the control group, respectively. CONCLUSION For the patients who failed to receive a surgical opera-tion on their hepatic metastasis from rectal cancer, celiac artery perfusion plus TACE is a more effective regimen for improvement of the clinical symp-toms and extension of the survival time, compared to intravenous chemo-therapy, and is a better choice for palliative therapy.

EFFECTS OF INFLAMMATORY CELLS IN COLD AND WARM ISCHEMIA-REPERFUSION INJURY OF THE GRAFTED LIVER

Objective To investigate whether the impairment of grafted livers after transplantation was induced by the same inflammatory cells both in cold and warm ischemia. Methods Male SD rats were divided into two groups at random,24 donor livers in each group were stored in Ringers solution at 4℃ for 120min or 240min of transplantation for blood sample and tissue specimen collection. Results Along with the prolongation of cold and warm ischemia time,the serum ALT,AST and LDH level increased gradually after transplantation.Under light microscopy,some hepatocytes presented necrosis after 3h and 6h of transplantation in cold ischemia,and neutrophilic infiltration in sinusoids were evident.Also,a large number of hepatocytes were necrotic 3h or 6h after transplantation in warm ischemia from NHBDs,and lymphocytic infiltration was evident in the sinusoids.The findings in electron microscopy was as the same as those of light microscopy,and the cells which infiltrated the sinusoids in warm ischemia were identified as T lymphocytes. Conclusion The impairment of grafted livers after transplantation appeared to be induced by two different kinds of inflammatory cells in cold and warm ischemia,that is,neutrophils mediated the cold ischemia-reperfusion,and T lymphocytes mediated the warm ischemia-reperfusion from NHBDs,but these findings are to be comfirmed in further investigations.