基于情境教学的高分子化学思政课堂探索——以聚合物的化学反应章节为例

将思政元素充分融入高分子化学课程中,可发挥专业基础课程在“立德树人”方面的重要作用。以聚合物的化学反应章节为例,将塑料垃圾的处理作为情境进行教学设计,构建以聚合物的化学反应知识为主体,以塑料垃圾的处理方法、绿色化学的思想、当前科技研究的前沿内容等元素为主导的教学思路。

高分子化学“聚合物的化学反应”项目式教学:芯片制造中的关键材料——光刻胶

以“芯片制造中的关键材料——光刻胶”为项目式教学主题,开展大学高分子化学中“聚合物的化学反应”的教学。从芯片的制造引入,通过学习光刻胶中感光树脂的合成方法了解高分子的基团反应特点以及功能高分子材料的合成策略;再通过光刻胶的光刻反应学习聚合物的交联和降解反应原理,进一步理解聚合物的化学反应实质;最后通过光刻胶在芯片制造中的应用实例,了解聚合物化学反应在实际生产的应用和实施方式。将科技前沿和实际生产相关知识与课堂教学相融合,培养学生的科学探究精神和创新意识。

酯交换法合成聚碳酸酯催化剂性能考察

以双酚A和碳酸二苯酯为原料,采用非光气熔融酯交换法合成聚碳酸酯。考察了氢氧化钾、氢氧化钠、四丁基氢氧化铵、碳酸钠、吡啶以及复合催化剂对聚碳酸酯合成反应速率及聚碳酸酯分子量和色差的影响。研究表明,氢氧化钾作为催化剂较适合于聚碳酸酯合成工艺,使用复合催化剂可以得到分子量较高、色差较低的聚碳酸酯。

LHQ-11催化剂在Unipol工艺上的中试研究

茂金属聚乙烯催化剂在Unipol气相法中试装置上进行了聚合评价试验。对催化剂活性、氢调敏感性、共聚性能、运行稳定性以及产品性能分析表明,LHQ-11催化剂的催化活性及其他综合性能与国外对比催化剂相当。

Spherizone工艺技术研究现状

Spherizone工艺是美国Lyondell Basell公司在Spheripol工艺基础上开发的最新颖、最先进的聚丙烯生产技术。介绍了Spherizone工艺技术特点、催化剂种类、反应器特点、聚丙烯产品典型牌号以及在薄膜、纤维、热成型和注塑领域的应用。Spherizone工艺作为最新一代的聚丙烯生产工艺,具有广阔的应用前景。

β成核剂对聚丙烯力学性能的影响

通过在抗冲聚丙烯基础树脂中添加自主研制的酰胺型高效β成核剂,在升高聚丙烯耐热温度的同时有效提高聚丙烯树脂EPS30R的冲击强度,研究酰胺型β成核剂PA-01、TMB-5和FB-1添加量对聚丙烯树脂EPS30R力学性能的影响,通过微观形态分析增韧的内在原因,并考察成核剂对聚丙烯树脂EPS30R的成核效果。结果表明,添加β成核剂后,聚丙烯的力学性能明显改善,且β成核剂诱导聚丙烯的成核效果较好。

Influence of CXCR4/SDF-1 axis on E-cadherin/β-catenin complex expression in HT29 colon cancer cells

AIM： To study the influence of CXCR4/stromal cell- derived factor-1 （SDF-1） axis on E-cadherin/β-catenin complex expression in HT29 colon cancer ceils and its underlying mechanisms. METHODS： Effect of SDF-1 on E-cadherin/β-catenin expression was detected by immunocytochemistry. E-cadherin and/3-catenin mRNA expression levels were measured by reverse transcriptase-polymerase chain reaction. SDF-l-induced phosphorylation of phosphati- dylinositol 3-kinase （PI3K）/AKT and β-catenin was detected by Western blotting. RESULTS： The E-cadherin and β-catenin mRNA ex-pression levels in HT29 cells were lower 48 h after incubated with SDF-1 at the concentrations of 20 and 40 ng/mL （P 〈 0.05）. SDF-l-induced significant phosphorylation of PI3K/AKT and β-catenin. AMD3100 and LY294002 inhibited the phosphorylation of PI3K/AKT and β-catenin. CONCLUSION： SDF-1 down-regulates the E-cadherin/ β-catenin complex expression in HT29 cells by decreasing mRNA synthesis and increasing β-catenin phosphorylation.

Mathematical Model and Advanced Control for Gas-phase Olefin Polymerization in Fluidized-bed Catalytic Reactors

In this study, the developments in modeling gas-phase catalyzed olefin polymerization fluidized-bed reactors （FBR） using Ziegler-Natta catalyst is presented. The modified mathematical model to account for mass and heat transfer between the solid particles and the surrounding gas in the emulsion phase is developed in this work to include site activation reaction. This model developed in the present study is subsequently compared with well-known models, namely, the bubble-growth, well-mixed and the constant bubble size models for porous and non porous catalyst. The results we obtained from the model was very close to the constant bubble size model, well-mixed model and bubble growth model at the beginning of the reaction but its overall behavior changed and is closer to the well-mixed model compared with the bubble growth model and constant bubble size model after half an hour of operation. Neural-network based predictive controller are implemented to control the system and compared with the conventional PID controller, giving acceptable results.

Osteopontin increases hepatocellular carcinoma cell growth in a CD44 dependant manner

AIM:To investigate the role of osteopontin(OPN) and its splice variants in the proliferation of hepatocellular carcinoma(HCC).METHODS:The expression of OPN variants in HCC cell lines as well as HCC tissue samples and nontumour tissue was studied using polymerase chain reaction.OPN variant cDNAs were cloned into a mammalian expression vector allowing both transient expression and the production of stable OPN expressing cell lines.OPN expression was studied in these cells using Western blotting,immunofluoresnce and enzyme linked immunosorbent assay.A CD44 blocking antibody and siRNA targeting of CD44 were used to examine the role of this receptor in the OPN stimulated cell growth observed in culture.Huh-7 cells stably expressing either OPN-A,-B or-C were injected subcutaneously into the flanks of nude mice to observe in vivo tumour growth.Expression of OPN mRNA and protein in these tumours was examined using reverse transcriptionpolymerase chain reaction and immunohistochemistry.RESULTS:OPN is expressed in HCC in 3 forms,the full length OPN-A and 2 splice variants OPN-B and-C.OPN variant expression was noted in HCC tissue as well as cognate surrounding cirrhotic liver tissue.Expression of these OPN variants in the HCC derived cell line Huh-7 resulted in secretion of OPN into the culture medium.Transfer of OPN conditioned media to na ve Huh-7 and HepG2 cells resulted in significant cell growth suggesting that all OPN variants can modulate cell proliferation in a paracrine manner.Furthermore the OPN mediated increase in cellular proliferation was dependent on CD44 as only CD44 positive cell lines responded to OPN conditioned media while siRNA knockdown of CD44 blocked the proliferative effect.OPN expression also increased the proliferation of Huh-7 cells in a subcutaneous nude mouse tumour model,with Huh-7 cells expressing OPN-A showing the greatest proliferative effect.CONCLUSION:This study demonstrates that OPN plays a significant role in the proliferation of HCC through interaction with the cell surface receptor CD44.Modulation of this interaction could represent a novel strategy for the control of HCC.

Bile-acid-activated farnesoid X receptor regulates hydrogen sulfide production and hepatic microcirculation

AIM: To investigate whether the farnesoid X receptor (FXR) regulates expression of liver cystathionase (CSE), a gene involved in hydrogen sulfi de (H2S) generation. METHODS: The regulation of CSE expression in response to FXR ligands was evaluated in HepG2 cells and in wild-type and FXR null mice treated with 6-ethyl chenodeoxycholic acid (6E-CDCA), a synthetic FXR ligand. The analysis demonstrated an FXR responsive element in the 5'-flanking region of the human CSE gene. The function of this site was investigated by luciferase reporter assays, chromatin immunoprecipitation and electrophoretic mobility shift assays. Livers obtained from rats treated with carbon tetrachloride alone, or in combination with 6-ethyl chenodeoxycholic acid, were studied for hydrogen sulphide generation and portal pressure measurement. RESULTS: Liver expression of CSE is regulated by bile acids by means of an FXR-mediated mechanism. Western blotting, qualitative and quantitative polymerase chain reaction, as well as immunohistochemical analysis, showed that expression of CSE in HepG2 cells and in mice is induced by treatment with an FXR ligand. Administration of 6E-CDCA to carbon tetrachloride treated rats protected against the down-regulation of CSE expression, increased H2S generation, reduced portal pressure and attenuated the endothelial dysfunction of isolated and perfused cirrhotic rat livers. CONCLUSION: These results demonstrate that CSE is an FXR-regulated gene and provide a new molecular explanation for the pathophysiology of portal hypertension.

Aberrant methylation of the 3q25 tumor suppressor gene PTX3 in human esophageal squamous cell carcinoma

AIM:To identify the novel methylation-silenced gene pentraxin 3(PTX3) in esophageal squamous cell carcinoma(ESCC).METHODS:PTX3 mRNA expression was examined in six human ESCC cell lines,one human immortalized normal esophageal epithelial cell line,primary ESCC tumor tissue,and paired adjacent nontumor tissue using reverse transcription polymerase chain reaction(RTPCR).Semi-quantitative immunohistochemistry was used to examine cellular localisation and protein levels.Methylation specific PCR and bisulphite genomic sequencing were employed to investigate the methylation of the candidate gene.RESULTS:In the majority of ESCC cell lines,we found that PTX3 expression was down-regulated due to gene promoter hypermethylation,which was further confirmed by bisulphite genomic sequencing.Demethylation treatment with 5-aza-2'-deoxycytidine restored PTX3 mRNA expression in ESCC cell lines.Methylation was more common in tumor tissues(85%) than in adjacent nontumor tissues(25%)(P < 0.01).CONCLUSION:PTX3 is down-regulated through promoter hypermethylation in ESCC,and could potentially serve as a biomarker of ESCC.

Clinicopathological Features of Non-familial Colorectal Cancer with High-frequency Microsatellite Instability

Objective To explore the clinicopathological features of non-familial colorectal cancer with high-frequency microsatellite instability (MSI-H). Methods One hundred and fifty patients with colorectal cancer who had no family history were enrolled in this study from June 2006 to June 2008. Five standard microsatellite loci including BAT25, BAT26, D2S123, D5S346, and D17S250 were amplified with immunofluorescent polymerase chain reaction. The patient information including age, sex, and tumor location was recorded. Pathological features including differentiation, mucinous differentiation, histological heterogeneity, and Crohn's-like reaction were observed under light microscope. The presence of tumor-infiltrating lymphocytes (TLs, CD4+ and CD8+) was detected by means of immunohistochemistry. A regression equation was obtained by stepwise logistic regression analysis to evaluate the relationship between MSI-H phenotype in colorectal cancer ands pathological features. Results MSI-H phenotype occurred in 13.33% of the 150 patients with non-familial colorectal cancer. Poor differentiation, histological heterogeneity, Crohn's-like reaction, and presence of TLs were found to be independent factors to identify MSI-H non-familial colorectal cancer. Logistic regression equation showed an overall sensitivity of 70.0%, specificity of 99.2%, and accuracy of 95.3% in identifying MSI-H non-familial colorectal cancer. Conclusion MSI-H non-familial colorectal cancer manifests specific pathological features, which may be relied upon for effective identification of that disease.

Statistical deduction and experimental verification on kinetic equations for the curing reactions of epoxy resins/amines

Based on three typical mechanisms (second-order, third-order and competitive mechanisms) for the curing reactions of the epoxy resins with amines, a pair of the kinetic equations (for primary and secondary aminations) was presented to explain the uniformity and relationship among the three different kinetic mechanisms of the reactions. The presented macro-equations were deduced from the kinetic micro-equations by the statistics method. And the constitutive equations were verified by experimental data at different reaction times and temperatures (95°C, 60°C and 39°C), taking diglycidyl ether of bisphenol A (DGEBA) /ethyleneamine (EA) as a model.

Expression and significance of microRNA-32 in multiple myeloma

Objective: This study was aimed to explore the expression of microRNA-32(miR-32) in multiple myeloma(MM), and study its association with β2-microglobulin and staging of MM by Durie-Salmon classification. Methods: The expression level of miR-32 in bone marrow mono-nuclear cells of MM were examined by real-time polymerase chain reaction(real-time PCR), and the correlations between the expression level of miR-32 and related clinic pathologic features β2-microglobulin, staging of MM by Durie-Salmon classification were further analyzed. Results: The expression of miR-32 in MM patients was obviously higher than that in normal control(P < 0.05). The expression of miR-32 in relapsed/ refractory MM patients was obviously higher than that in newly diagnosed MM patients. The expression of miR-32 in MM patients decreased after chemical therapy than that before treatment, especially in effective group(P < 0.05). There was no statistically significant change in ineffective/progress group after chemical therapy(P > 0.05).The expression of miR-32 was associated to staging of MM and β2-microglobulin level. Conclusion: Expression level of miR-32 in MM patients is significantly higher than that in normal bone marrow, these data indicated that miR-32 may play an important role in the development of MM. High-regulated expression of miR-32 was associated with β2-microglobulin and staging of MM by Durie-Salmon classification.

Impact of radiation,melting,and chemical reaction on magnetohydrodynamics nanoparticle aggregation flow across parallel plates

The heat transfer between two corresponding plates,disks,and concentric pipes has many applications,including water cleansing and lubrication.Furthermore,TiO_(2)-water-based nanofluids are used widely because it is useful for operating and controlling the temperature,especially in photovoltaic technology and solar panels.Motivated by these applications,the current study is based on the nanoparticle aggregation effect on magnetohydrodynamics(MHD)flow via rotating parallel plates with the chemical reaction.To achieve maximum heat transportation,the Bruggeman model is used to adapt the Maxwell model.Also,melting and thermal radiation effects are considered in the modeling to discuss heat transport.The Runge-Kutta-Fehlberg 4th−5th order method is used to attain numerical solutions.The main focus of this study is to see the thermodynamic behavior considering several aspects of nanoparticle aggregation.The heat transfer rate between the parallel plates is enhanced by improving the thermophoresis,radiation,and Brownian motion parameters.The rise in Schmidt number and chemical reaction rate parameter decreases the concentration distribution.This study will be helpful in enhancing the thermal efficiency of photovoltaic technology in solar plates,water purifying,thermal management of electronic devices,designing effective cooling systems,and other sustainable technologies.

Effects of 4-amino-2-methyl-cantharidinimide on GABA_C receptors

The antiepileptic effect of 4-amino-2-methyl-cantharidinimide（AMC） was reported,but its mechanism remains unknown.In this study,we investigated the effects of AMC on a rat model of penicillin-induced epilepsy.The doses of 88 and 22 mg/kg AMC and the dose of 154 mg/kg sodium valproate（VPA） were administered intragastrically（i.g.） 30 min before penicillin injection,respectively.The epileptiform activity was verified by electrocorticographic（ECoG） recordings.The levels of GABA and GABAC receptors in hippocampus were determined by immunohistochemistry,and real-time polymerase chain reaction（RT-PCR） technique was used to detect the mRNA expression of GABAC receptor ρ2.The mean frequency and amplification of spike epileptiform activity were significantly decreased in AMC and VPA-pretreated rats compared with those of non-pretreated penicillin-induced epilepsy（PIE） group.The levels of GABA,GABAC receptors and the mRNA expression of GABAC receptors ρ2 in AMC and VPA-pretreated rats were significantly increased as compared with PIE group.These findings indicate that AMC and VPA have an antiepileptic effect on PIE in rats,and the antiepileptic effect of AMC may be mediated by the GABAC receptors and GABA.

Effect of Wuziyanzong pill on levels of sex hormones, and expressions of nuclear- associated antigen Ki-67 and androgen receptor in testes of young rats

OBJECTIVE: To evaluate the effects of Wuziyanzong pill on the levels of serum follicle stimulating hormone(FSH), luteinizing hormone(LH), testosterone(T) and the expressions of nuclear-associated antigen Ki67(Ki67), androgen receptor(AR) in testes of young rats.METHODS: Sixteen 20-day-old Wistar male rats were randomly divided into control and treatment group(n = 8). Rats in treatment group were administered Wuziyanzong pill by gavage; rats in control group administered the same volume of saline. After 10 days of treatment, the rats were killed, and then serum and testes were taken. The levels of FSH, LH and T were measured by radioimmunoassay(RIA). The histology of seminiferous tubule was observed by hematoxylin-eosin(HE) staining. The expression of Ki67 was detected by immunohistochemical assay(IHC). The m RNA level of Ki67, ARand CK-18 was detected with quantitative real-time polymerase chain reaction(Q-RT-PCR), the protein level of AR and CK-18 were tested by Western blot.RESULTS: Compared with control group, T level in treatment group increased significantly(P < 0.05).HE staining showed that both leydig cells and germ cells increased in treatment group. Expressions of Ki67 and AR became higher after treatment. There were no changes in CK-18 expression.CONCLUSION: Wuziyanzong pill can up-regulate AR level to promote germ cell proliferation and differentiation in young male rats.

Recent advances of the Bergman cyclization in polymer science

The Bergman cyclization has strongly impacted on a number of fields including pharmaceutics, synthetic chemistry, and material science. The diradical intermediates stemmed from enediynes can not only cause DNA cleavage under physiological conditions but also function as monomer or initiator participants in polymer science. The homo-polymerization of enediynes through the Bergman cyclization to fabricate conjugated polymers is a fascinating strategy due to the advantages of facial operation, high efficiency, tailored structure, and catalyst-free operation. Moreover, conjugated polymers generated through the Bergman cyclization show many remarkable properties, such as excellent thermal stability, good solubility, and processability, which enables these polymers to be further manufactured into carbon-rich materials. Recent times have seen extensive efforts devoted to the application of the Bergman cyclization in polymer science and materials chemistry. A variety of synthetic strategies have been developed to fabricate structurally unique materials via the Bergman cyclization, including the fabrication of rod-like polymers with polyester, dendrimers and chiral imide side chains, functionalization of carbon nanomaterials by surface-grafting conjugated polymers, formation of nanoparticles by intramolecular collapse of single polymer chains, and the construction of carbon nanomembranes with different morphologies. Future developments involving the Bergman cyclization in polymer science, probably by altering the reaction mechanism to precisely control the microstructure of polymeric products, are also proposed in this review article.