对定压成型陶瓷磨具组织号统计规律的探讨

本文通过用数理统计方法处理大量磨具组织号数据,证明了定压成型陶瓷磨具生产工艺因素在允差内变动所引起的磨具组织号波动遵从正态分布规律,并确定了波动幅度的概率,同时探索出组织号与结合剂量间的直线关系。

45钢高、低温硼稀土粉末共渗层组织与性能分析

分别对 4 5钢进行高、低温硼稀土粉末共渗处理 ,分析测试了共渗层的组织、厚度及显微硬度 ,并对试样的耐磨性、耐蚀性和脆性等性能进行对比。结果表明 ,低温共渗层比高温共渗层致密 ,疏松、孔洞少 ,耐蚀性与早期耐磨性优于高温共渗层 ;高温共渗层的脆性小于低温共渗层 ,且渗层厚、硬度高。

伤科Ⅱ号膏药对急性筋伤兔模作用的实验研究

为观察评价伤科Ⅱ号膏药对急性筋伤的药效作用,建立急性筋伤兔模,分为伤科Ⅱ号组(A组),扶他林软膏组(B组),空白对照组(C组),观测对外表损伤指数、血浆黏度、病理学检查、前列腺E2(PGE2)含量的影响。结果伤科Ⅱ号组在消肿散瘀、降低血浆黏度、损伤组织修复方面均优于扶他林组(P<0.05),在抑制PGE2合成上逊于扶他林组(P<0.05),两组与空白药物组比较均有显著性差异((P<0.01)。表明伤科Ⅱ号膏药治疗急性筋伤有确切良好的疗效。

少先队组织微信公众号的建设与运营——以“嘉定红领巾”微信公众号为例

在互联网时代,微信公众号逐渐成为少先队组织进行思想启蒙和价值观塑造的载体,本文以“嘉定红领巾”微信公众号为例,从创建背景与意义、运营与成果等方面进行分析,研究总结“嘉定红领巾”微信公众号“新媒体+”运营模式,并基于5W模式、使用与满足理论构建家校社合作的“全员育人”新平台,从传播者、传播内容、受传者、传播媒介、传播效果五个方面对“嘉定红领巾”微信公众号运营成果进行分析梳理。在为基层少先队组织微信公众号建设提供参考、为少先队社会化网络宣传阵地建设提供启发的同时,少先队组织微信公众号建设还面临着如何处理巩固和发展的关系、如何处理内容与形式的关系、如何处理特殊与一般的关系等问题和挑战。

Microstructure and high temperature tribological behavior of laser cladding Ni60A alloys coatings on 45 steel substrate

The crack-free Ni60 A coating was fabricated on 45 steel substrate by laser cladding and the microstructure including solidification characteristics, phases constitution and phase distribution was systematically investigated. The high temperature friction and wear behavior of the cladding coating and substrate sliding against GCr15 ball under different loads was systematically evaluated. It was found that the coating has homogenous and fine microstructure consisting of γ（Ni） solid solution, a considerable amount of network Ni-Ni3 B eutectics, m^23C6 with the floret-shape structure and Cr B with the dark spot-shape structure uniformly distributing in interdendritic eutectics. The microhardness of the coating is about 2.6 times as much as that of the substrate. The coating produces higher friction values than the substrate under the same load condition, but the friction process on the coating keeps relatively stable. Wear rates of the coating are about 1/6.2 of that of the substrate under the higher load（300 g）. Wear mechanism of the substrate includes adhesion wear, abrasive wear, severe plastic deformation and oxidation wear, while that of the coating is merely a combination of mild abrasive wear and moderate oxidation wear.

Dynamic expression of extracellular signal-regulated kinase in rat liver tissue during hepatic fibrogenesis

AIM： To investigate whether extracellular signal-regulated kinase 1 （ERK1） is activated and associated with hepatic stellate cell （HSC） proliferation in fibrotic rat liver tissue.METHODS： Rat hepatic fibrosis was induced by bile duct ligation （BDL）. Histopathological changes were evalo uated by hernatoxylin and eosin staining, and Masson＇ s trichrorne method. ERK1 mRNA in rat liver tissue was determined by reverse transcription-polyrnerase chain reaction, while the distribution of ERK1 was assessed by irnrnunohistochernistry. ERK1 protein was detected by Western blotting analysis. The number of activated HSCs was quantified after alpha smooth muscle actin （α-MA） staining.RESULTS： With the development of hepatic fibrosis, the positive staining cells of α-SMA increased obviously, and mainly resided in the portal ducts. Fiber sepia and perisinuses were accompanied with proliferating bile ducts. The positive staining areas of the rat livers in model groups 1-4 wk after ligation of common bile duct （12.88% ± 2.63%, 22.65% ± 2.16%, 27.45% ± 1.86%, 35.25% ± 2.34%, respectively） were significantly larger than those in the control group （5.88% ± 1.46%, P 〈 0.01）. With the development of hepatic fibrosis, the positive cells of ERK1 increased a lot, and were mainly distributed in portal ducts, fiber sepia around the bile ducts, vascular endothelial cells and perisinusoidal cells. Western blotting analysis displayed that the expression of ERK1 and ERK1 protein was up-regulated during the model course, and its level was the highest 4 wk after operation, being 3.9-fold and 7.2-fold higher in fibrotic rat liver than in controls. ERK1 mRNA was expressed in normal rat livers as well, which was up-regulated two days after BDL and reached the highest 4 wk after BDL. The expression of ERK1 was positively correlated with α-MA expression （r = 0.958, P 〈 0.05）.CONCLUSION： The expression of ERK1 protein and mRNA is greatly increased in fibrotic rat liver tissues, which may play a key role in HSC proliferation and hepatic fibrogenesis.

Wnt signaling in disease and in development

The highly conserved Wnt secreted proteins are critical mediators of cell-to-cell signaling during development of animals. Recent biochemical and genetic analyses have led to significant insight into understanding how Wnt signals work. The catalogue of Wnt signaling components has exploded. We now realize that multiple extracellular, cytoplasmic, and nuclear components modulate Wnt signaling. Moreover, receptor-ligand specificity and multiple feedback loops determine Wnt signaling outputs. It is also clear that Wnt signals are required for adult tissue maintenance. Perturbations in Wnt signaling cause human degenerative diseases as well as cancer.

Effect of BN52021 on NFκ-Bp65 expression in pancreatic tissues of rats with severe acute pancreatitis

AIM： To investigate dynamic changes and significance of expression of NF-κBp65 in pancreatic tissues of rats with severe acute pancreatitis （SAP）, as well as BN52021 effects. METHODS： Wistar male rats were randomly divided into negative control group （NC group, n = 60）, SAP-model group （SAP group, n = 60）, and BN52021-treated group （BN group, n = 60）, and each of the above groups was respectively divided into 6 subgroups at different time points after operation （1 h, 2 h, 3 h, 6 h, 12 h, and 24 h） （n = 10）. By RT-PCR and Western blot, NF-κBp65 mRNA and its protein expression in pancreatic tissues of rats were detected respectively. RESULTS： The expression of NF-κBp65 mRNA dynamically changed in both SAP groups and BN groups. The mRNA level was higher in SAP groups than NC groups at 2 h, 3 h, 12 h, and 24 h after operation （P 〈 0.05）, higher in BN groups than NC groups at all time points （P 〈 0.05）, and higher in BN groups than SAP group at 1 h （P 〈 0.05）. The NF-κBp65 protein level was higher in SAP groups than NC groups at 1 h, 3 h, and 6 h （P 〈 0.01）, and 2 h, 12 h, and 24 h （P 〈 0.05）, higher in BN groups than NC groups at all time points （P 〈 0.05）, and lower in BN groups than SAP groups at 1 h, 3 h, and 6 h （P 〈 0.05）. CONCLUSION： The expression of NF-κBp65 in pancreatic tissues is dynamically changed and the changes play an important role in pathogenesis of SAR BN52021 exerts therapeutic effects through reducing the expression level of NF-κBp65 protein in the early stage of SAR

Clinical significance of expression of apoptotic signal proteins in gastric carcinoma tissue

AIM: To evaluate the expressions of apoptotic signal proteins FADD, TRADD, FasL, Fas, and NFκB in gastric carcinoma tissues and their clinical significance. METHODS: Western blot immune trace method was adopted to detect the expressions of apoptotic signal proteins FADD, TRADD, FasL, Fas, and NFκB in 55 tissue specimens of gastric carcinoma. RESULTS: Five apoptotic signal proteins had different expressions in the gastric carcinoma samples and their expressions were not correlated to age (P= 0.085). Expressions of the FADD, FasL, Fas, and NFkB proteins reduced with increase of the volume of tumor with the exception of increased expression the TRADD protein (64.7-71.1%, P= 0.031). With gradual increase of the malignancy of gastric carcinoma tissues, expressions of the FADD, FasL, and Fas proteins decreased (78.6-28.0%, P= 0.008; 78.6-65.9%, P= 0.071; 100.0-46.3%, P= 0.014), while expressions of the TRADD and NFkB proteins increased (42.9-78.1%, P= 0.063; 78.6-79.1%, P= 0.134). With gradual increase of serum CEA, expression of the FADD protein decreased (62.5-34.0%, P = 0.073), but expressions of the TRADD, FasL, Fas, and NFκB proteins increased (0.0-80.8%, P=0.005; 62.5-70.2%, P= 0.093; 0.0-70.2%, P=0.003; 62.5-80.9%, P= 0.075). When compared to the tissues of gastric carcinoma without metastasis, the positive rate of expressions of the FADD and FasL proteins increased, whereas expressions of the TRADD, FADD, and NFkB proteins decreased. There was no significant difference between them (P= 0.095). CONCLUSION: Gastric carcinoma is endurable to Fas-related apoptosis and apoptotic signal proteins are differently expressed in gastric carcinoma.

Mesenchymal stromal cells' role in tumor microenvironment:involvement of signaling pathways

Mesenchymal stromal cells(MSCs) are adult multipotent stem cells residing as pericytes in various tissues and organs where they can differentiate into specialized cells to replace dying cells and damaged tissues. These cells are commonly found at injury sites and in tumors that are known to behave like "wounds that do not heal." In this article, we discuss the mechanisms of MSCs in migrating, homing, and repairing injured tissues. We also review a number of reports showing that tumor microenvironment triggers plasticity mechanisms in MSCs to induce malignant neoplastic tissue formation, maintenance, and chemoresistance, as well as tumor growth. The antitumor properties and therapeutic potential of MSCs are also discussed.

Metallurgical behavior and variation of vibro-acoustic signal during preheating assisted friction stir welding between AA6061-T6 and AA7075-T651 alloys

The present work investigated the effects of pin profiles(cylindrical and square),pin eccentricity(0.5 mm and 1 mm)in cylindrical tool and preheating(secondary heating)on metallurgical behavior,variation of vibro-acoustic signal pattern and joint strength during friction stir welding(FSW)between AA6061-T6 and AA7075-T651 alloys.The eccentric tool pins were observed to provide good flowability and intermixing between dissimilar metals,increased the size of stir zone,and the grains in stir zone were sufficiently finer with eccentric tool pin than concentric pin.The magnitude of vibro-acoustic signal increased when shoulder plunging started and drop in signal was noted when the tool shoulder reached its desired depth.The signal magnitude was noted to be higher in welding stage compared to tool plunging stage as the tool took in fresh material during tool movement along the weld path.Preheating the workpiece prior to pin plunging and during welding notably influenced the flow behavior and mixing pattern,and the grains in stir zone were slightly coarser than those in specimen without preheating.Significant reduction in the magnitude of the signal was also observed after preheating.Tensile and flexural strength of joints were also improved slightly when additional heating was employed.

Promoting human embryonic stem cell renewal or differentiation by modulating Wnt signal and culture conditions

We previously showed that Wnt3a could stimulate human embryonic stem （hES） cell proliferation and affect cell fate determination. In the absence of feeder cell--derived factors, hES cells cultured under a feeder-free condition survived and proliferated poorly. Adding recombinant Wnt3a in the absence of feeder cell derived-factors stimulated hES cell proliferation but also differentiation. In the present study, we further extended our analysis to other Wnt ligands such as Wntl and Wnt5a. While Wntl displayed a similar effect on hES cells as Wnt3a, Wnt5a had little effect in this system. Wnt3a and Wntl enhanced proliferation of undifferentiated hES cells when feeder-derived self-renewal factors and bFGF are also present. To explore the possibility to promote the proliferation of undifferentiated hES cells by activating the Wnt signaling, we overexpressed Wnt3a or Wntl gene in immortalized human adult fibroblast （HAFi） cells that are superior in supporting long-term growth of undifferentiated hES cells than primary mouse embryonic fibroblasts. HAFi cells with or without a Wnt tmnsgene can be propagated indefinitely. Over-expression of the Wnt3a gene significantly enhanced the ability of HAFi feeder cells to support the undifferentiated growth of 3 different hES cell lines we tested. Co-expression of three commonly-used drug selection genes in Wnt3a-overpressing HAFi cells further enabled us to select rare hES clones after stable transfection or transduction. These immortalized engineered feeder cells （W3R） that co-express growth-promoting genes such as Wnt3a and three drug selection genes should empower us to efficiently make genetic modified hES cell lines for basic and translational research.

Diagnostic efficacy of gadoxetic acid-enhanced MRI for hepatocellular carcinoma and dysplastic nodule

AIM:To evaluate the relationship between the signal intensity of hepatobiliary phase images on gadoxetic acid-enhanced magnetic resonance imaging(MRI)and histological grade.METHODS:Fifty-nine patients with 82 hepatocellular lesions were evaluated retrospectively.Hepatobiliary phase images on gadoxetic acid-enhanced MRI were classified into 3 groups:low,iso or high.Angiographyassisted computed tomography(CT)findings were also classified into 3 groups:CT during arterial portography,and CT hepatic arteriography:A:iso,iso or low;B:slightly low,iso or low;;and C:low,high.We correlated angiography-assisted CT,hepatobiliary phase findings during gadoxetic acid-enhanced MRI and histological grades.Furthermore,correlations between MRI findings and histological grade for each hemodynamic pattern were performed.Correlations among radiologicaland pathological findings were statistically evaluated using the chi-square test and Fisher's exact test.RESULTS:There was a significant correlation between histological grade and hemodynamic pattern(P<0.05).There was a significant correlation between histological grade and signal intensity in the hepatobiliary phase(P<0.05)in group A lesions.There was no significant correlation between histological grade and signal intensity in the hepatobiliary phase in group B or C lesions(P>0.05).CONCLUSION:Signal intensity in the hepatobiliary phase correlated with histological grade in the lesions that maintained portal blood flow,but did not correlate in lesions that showed decreased or defective portal blood flow.

JAK/STAT signaling regulates tissue outgrowth and male germline stem cell fate in Drosophila

In multicellular organisms, biological activities are regulated by cell signaling. The various signal transduction path- ways regulate cell fate, proliferation, migration, and polarity. Miscoordination of the communicative signals will lead to disasters like cancer and other fatal diseases. The JAK/STAT signal transduction pathway is one of the pathways, which was first identified in vertebrates and is highly conserved throughout evolution. Studying the JAK/STAT signal transduc- tion pathway in Drosophila provides an excellent opportunity to understand the molecular mechanism of the cell regu- lation during development and tumor formation. In this review, we discuss the general overview of JAK/STAT signaling in Drosophila with respect to its functions in the eye development and stem cell fate determination.

Tissue factor/FVII regulates doxorubicin-induced apoptosis in glioblastoma via activating PI3K/Akt signaling

Objective： To investigate the role of tissue factor （TF） in chemotherapeutic reagent - induced apoptosis on human glioblastoma and explore its mechanism. Methods： The expression of TF was examined by Western blotting. The cytotoxicity of doxorubicin was determined by WST assay. The activation of Caspase-3 and PARP induced by adoxorubicin were tested by Western blotting. Results： Human glioblastoma cell line U373MG expressed high level of TF while LN-229 was with low-TF level. The chemotherapeutic reagent doxorubicin revealed stronger cytotoxic effect on high-TF U373MG cells than IowoTF LN-229 cells. Enforced strong expression of TF was achieved by transfection of TF-pcDNA3 combinant on LN-229 cells in a dose-dependent manner. Enforced TF expression in transfected LN-229 cells not only impaired the doxorubicin-induced cleavage of Caspase-3 and PARP, but also inhibited the cytotoxic effect of doxorubicin. Furthermore, activation of Akt was strong in high-TF U373MG cells but weak in IowoTF LN-229 cells. Incubation of factor VII （FVII） with enforced TF-expressing LN-229 cells increased the phosphorylaUon of Akt in a time-dependent manner. Conclusion： These results suggest that over-expression of TF on glioblastoma could inhibit doxorubicin-induced apoptosis. Interaction of FVII and TF activates the downstream PI3K/Akt pathway. Tumor-derived over-expression of TF might play a role in chemotherapy resistance in glioblastoma, at lest in part, by activating PI3K/Akt-mediated survival and anti-apoptotic mechanism through the interaction of TF/FVII signaling.

Spectral characteristics of micro-seismic signals obtained during the rupture of coal

This study was performed to investigate the spectral characteristics of micro-seismic signals observed during the rupture of coal. Coal rupture micro-seismic observations were obtained on a test system that included an electro-hydraulic servo pressure tester controlled by a YAW microcomputer, a micro-seismic sensor, a loading system, and a signal collection system. The results show that the micro-seismic signal increases with increasing compressive stress at the beginning of coal rupture. The signal remains stable for a period at this stage. A large number of micro-seismic signals appear immediately before the main rupture event. The frequency of micro-seismic events reaches a maximum immediately after the coal ruptures. Micro-seismic signals were decomposed into several Intrinsic Mode Functions (IMF's) by the empirical mode decomposition (EMD) method using a Hilbert-Huang transform (HHT). The main fre- quency band of the micro-seismic signals was found to range from 10 to 100 Hz in the Hilbert energy spectrum and from marginal spectrum calculations. The advantage of applying an HHT is that this can extract the main features of the signal. This fact was confirmed by an HHT analysis of the coal micro-seis- mic signals that shows the technique is useful in the field of coal rupture.

The expression and clinical significance of β-catenin and colorectal cancer stem cells marker EpCAM^(high)/CD44^+ in colorectal cancer

Objective： The aim of the study was to explore the role of Wnt βcatenin signalling pathway in the maintenance, invasion and metastasis of colorectal cancer stem cells. Methods： Double immunohistochemical staining was used to detect the expression of EpCAMhigh/CD44~ which is regarded as the marker of colorectal cancer stem cells in 80 cases of colorectal cancer and their corresponding liver metastases. The SP method of immunohistochemistry was used to detect the expression of the key protein βcatenin in the Wnt pathway in these tissue. The expression and correlation of ^-catenin and EpCAMh^gh/ CD44＋ in colorectal cancer were analyzed and their role on the biological behavior of colorectal cancer was explored. Results： The abnormal expression of βcatenin was significantly higher in colorectal cancer than in the paraneoplastic normal intes- tinal mucosa [55% （44/80） vs 10% （2/20）, P 〈 0.05]. The positive expression of EpCAMhigh/CD44＋ was significantly higher in colorectal cancer than in the paraneoplastic normal intestinal mucosa [66.25% （53/80） vs 0% （0/20）, P 〈 0.05]. In the 80 cases of colorectal cancer, the abnormal expression of ^-catenin has no correlation with gender （P = 0.079）, age （P = 0.416） and the magnitude （P = 0.816） of the tumor （P 〉 0.05）, but it was significantly correlated with degree of differentiation （P = 0.001）, depth of invasion （P = 0.001）, clinical stage （P = 0.000） and metastasis （P = 0.000）. In the colorectal cancer, the expression of EpCAMhi^h/CD44~ cells has no correlation with gender （P = 0.934） and the magnitude （P = 0.160） of the tumor （P 〉 0.05）, but was significantly correlated with age （P = 0.021）, degree of differentiation （P = 0.013）, depth of invasion （P = 0.000）, clinical stage （P = 0.000） and metastasis （P = 0.000）. In the corresponding liver metastases, we could also detecte EpCAMhih/CD44＋ cells. In cases with abnormal expression of βcatenin, the positive expression rate of EpCAMhigh/CD44＋ was significantly higher than those with normal expression of β-catenin （84.1% vs 44.4%）, and the difference was statistically significant （P 〈 0.05）. Conclusion： The abnormal activation of Wnt β-catenin signalling pathway may prompt the abnormal proliferation of the colorectal cancer stem cells, which leads to the recurrence and metastasis of the cancer.

The role of Tbx2 in pancreatic cancers and its regulation by Wnt/β-catenin signaling

Objective: To investigate the expression of Tbx2 protein in pancreatic cancer tissues and its molecular regulation mechanism by Wnt/β-catenin signaling. Methods: 49 pancreatic cancer and 13 non-cancer tissue specimens were obtained and examined the expression of Tbx2, and the correlation between the expression of Tbx2 and clinicopathological parameters was analyzed. The immunohistochemistry, immunocytochemistry, RT-PCR and Western blot assay methods were used to detect the changes of expression levels of β-catenin and Tbx2. Results: Tbx2 was amplified in 34 of 49 pancreatic cancers, and in 13 non-cancer tissues, only one sample amplified. The further study demonstrated that Tbx2 had a significant positive correlation with tumor differentiation degree and clinical stage, but it did not relate to the sex, age and the disease region. Inhibi-tion of β-catenin degradation through the treatment of pancreatic cancer cells SW1990 with different concentrations of lithium chloride indicated that accumulation of β-catenin was sufficient to induce TBX2 expression. Conclusion: TBX2 gene plays an important role in the occurrence and development of pancreatic cancer and the accumulation of β-catenin contributes to the expression of TBX2. The Wnt/β-catenin signaling pathway participates the regulation of TBX2 in pancreatic cancer cells.

Modeling of Biological Tissues Response to Radio Frequency （RF）： Towards Remote Sensing of Electrocardiography Signal

Premature newborns are at high risk of developing infections, so they require continuous monitoring of vital parameters for long periods of time, until they approximately reach the pregnancy due date. ECG （electrocardiography） is one of the most widely used method for evaluating the structure-function relationship of the heart in health and in sickness. Due to incomplete skin development, premature newborns have some special requirements to the ECG monitoring electrodes. Contact ECG monitoring adversely affects the health and comfort of the newborns. The goal of this study is to determine the feasibility of using RF （radio frequency） in ECG signal remote sensing. This requires studying the interaction mechanisms between RF fields and biological tissues The ECG current propagated from the heart through the skin has an effect on the permittivity of the skin which is frequency dependent. Thus, the feasibility of detecting the change of the relative permittivity in the presence of ECG signal is also discussed. The RF biological tissues response is simulated using MATLAB software in preparation for experimental validation.

The effect of low-dose total body irradiation on tumor-inhibition and signal transduction in tumor tissues of mice bearing S180 sarcoma

Objective： By studying the influence of low-dose total body irradiation to proliferating cell nuclear antigens （PCNA）, epidermal growth factor receptor （EGFR）, erythropoietin （EPO） and vascular endothelial growth factor receptor （VEGFR） of tumor tissues in mice bearing S180 sarcoma, to further explore the mechanism of low doses radiation. Methods：S180 sarcoma cells were implanted subcutaneously into 58 male Kunming mice. Randomly these mice were divided into sham-irradiation （S） group and low-dose radiation （LDR） group. 12 days after implantation, the mice in LDR group were once delivered 75 mGy total-body ^60Co y-ray irradiation, while the mice in S group were left without irradiation. Then the mice in LDR group were executed at 6 h （LDR-6h group）, 12 h （LDR-12 h group）, 24 h （LDR-24 h group）, 48 h （LDR-48 h group） and 72 h （LDR-72h group） after irradiation. Tumor tissues were weighed and histological observed. Immunohistochemical staining was used to detect the expression of PCNA, VEGF, EPO and VEGFR of tumor tissues. Results： Though there was no significant difference between LDR group and S group in tumor weight, after irradiation the expression of PCNA and EPO of tumor tissues in LDR group decreased with time. LDR-24h, LDR-48h and LDR-72h groups were all statistically significantly different from S group. The expression of EGFR and VEGFR also decreased, and LDR-24h group was the lowest （P 〈 0.05）. Conclusion： Seventy-two h after low-dose total body irradiation, there was no significant change in tumor size of mice bearing S180 sarcoma. Low-dose total body radiation decreased the expression of PCNA inhibiting tumor growth; reduced the expression of EGFR in tumor tissue impacting the signal transduction of tumor cells. The study also indicated that low-dose total body irradiation, within a certain period of time, can decrease the expression of hypoxia factor EPO and VEGFR, which may improve the situation of tumor hypoxia and radiosensitivity of tumor itself.