基于氢键的侧链型超分子电光聚合物的制备与表征

设计并制备了一种基于氢键的侧链型超分子聚乙烯基吡啶电光聚合物,非线性发色团与聚合物主链之间的氢键作用经红外光谱进行表征。采用氢键将发色团挂接到聚合物,可一定程度地抑制发色团分子的聚集,防止宏观相分离,实现发色团的高浓度掺杂。同时,利用超分子氢键作用挂接也可在一定程度上抑制发色团间的偶极-偶极相互作用力,测得此体系极化电光聚合物薄膜的最大电光系数为17.6pm/V。

改进CNDO双电子排斥积分近似的新方法及链分子构象能的计算

本文以CNDO为例,分析了半经验量子化学方法用于聚合链构象计算中所遇到的困难,指出双电子排斥积分的近似是产生这类困难的原因。提出了在双电子排斥积分中附加与旋转键对称性有关的项,并计算了聚乙烯的构象能图,得到了与实验相吻合的结果。

深圳市非淋菌性尿道炎患者解脲支原体、人型支原体及沙眼衣原体感染的分子流行病学调查

目的了解深圳市非淋菌性尿道炎(NGU)患者解脲支原体(Uu)、人型支原体(M h)及沙眼衣原体(CT)感染的流行病学状况。方法采用聚合酶链反应(PCR)方法对2001年2月～2004年11月在深圳市第二人民医院门诊部就诊的2016例NGU患者的泌尿生殖道分泌物同时进行Uu、M h和CT的DNA检测。结果690份男性标本中,407份标本呈现阳性结果,总阳性检出率高达58.98%(407/690),其中Uu、M h和CT单项阳性检出率分别为21.74%、6.67%和30.57%;1326份女性标本中,845份标本呈现阳性反应,总阳性检出率高达63.72%(845/1326),其中Uu、M h和CT单项阳性检出率分别为34.16%、8.37%和21.19%,男性CT阳性检出率明显高于女性(P<0.05),而女性Uu阳性检出率则明显高于男性(P<0.05),M h的阳性检出率无明显性别差异(P>0.05)。三个项目总的重叠阳性率为20.04%,其中Uu+CT重叠阳性率为9.57%,Uu+M h为7.77%,CT+M h为4.12%,Uu+M h+CT为1.24%。2001、2002、2003和2004年三个项目总的阳性检出率分别为49.11%、58.21%、58.63%和72.56%。结论Uu、M h和CT是深圳市NGU最重要的致病病原体,总感染率高达62.10%,且呈逐年升高趋势,三者间的重叠感染在NGU的流行病学中扮演着重要的角色。

基于分子动力学模拟的天然橡胶黏弹性材料力学行为

以天然橡胶为例,采用分子动力学模拟方法,研究了单轴拉伸条件下材料分子链聚合度参数p、环境温度T和加载率R对黏弹性材料力学性能的影响.结果表明,材料应力随分子链聚合度和加载率的增加而增加,随温度的升高而降低,低温高频下材料呈现出塑性特点.在R=10^(8)s^(-1),T=250 K的条件下,p=20,40时,材料应力峰值分别为79.8和99.8 MPa;当p=40,R=10^(10)s^(-1)时,T=100,250 K条件下,应力幅值分别为134.9和103.9 MPa;在p=40,T=250 K情况下,R=10^(9),10^(10)s^(-1)时,应力峰值分别为122.7和134.9 MPa.在加载过程中,非键结势能对系统总势能的变化起主导作用,分子动力学模拟方法可以较好地分析分子链聚合度、环境温度和加载率等参数对黏弹性材料应力、系统能量和自由体积变化的影响.

Potentially predictive microRNAs of gastric cancer with metastasis to lymph node

AIM:To detect the expression of 60 microRNAs(miRNAs)in gastric cancer tissues and find new predictive biomarkers of gastric cancer with metastasis.METHODS:The expressions of 60 candidate miRNAs in 30 gastric cancer tissues and paired normal tissues were detected by stem-loop real-time reverse transcription-polymerase chain reaction.After primary screening of miRNAs expression,5 selected miRNAs were further testified in another 22 paired gastric tissues.Based on the expression level of miRNAs and the status of metastasis to lymph node(LN),receiver-operating-characteristic(ROC)curve were used to evaluate their ability in predicting the status of metastasis to LN.RESULTS:Thirty-eight miRNAs expressions in gastric cancer tissues were significantly different from those in paired normal tissues(P<0.01).Among them,31miRNAs were found to be up-expressed in cancer tissues and 1 miRNAs were down-expressed≥1.5 fold vs paired normal gastric tissue.Five microRNAs(miR-125a-3p,miR-133b,miR-143,miR-195 and miR-212)were differently expressed between different metastatic groups in 30 gastric cancer biopsies(P<0.05).Partial correlation analysis showed that hsa-mir-212 and hsa-mir-195 were correlated with the status of metastasis to LN in spite of age,gender,tumor location,tumor size,depth of invasion and cell differentiation.ROC analysis indicated that miR-212 and miR-195 have better sensi-tivities(84.6%and 69.2%,respectively)and specifici-ties(both 100%)in distinguishing biopsies with metastasis to LN from biopsies without metastasis to LN.CONCLUSION:miR-212 and miR-195 could be independent biomarkers in predicting the gastric cancer with metastasis to LN.

More attention should be paid on the interpretation of gene expression data

Molecular profiling of gene expression is important for determining signatures in cancer progression and diagnosis.For this purpose,polymerase chain reactionbased techniques are preferentially used as a feasible and sensitive approach.Nevertheless,when relative quantitative analyses are performed on gene expression,the interpretation of mathematical equations must be carefully done.This letter to the editor is focused on recently published gene expression data in World Journal of Gastroenterology by Ozmen et al demonstrating increased levels of LYVE-1,VEGFR-3 and CD44 genes in gastric cancer samples compared to nonneoplastic gastric tissues.However,there are major concerns about misinterpretation of the gene expression data obtained with the 2-ΔΔCt relative quantitative method.In the study,2-ΔΔCt values calculated for many samples were smaller than 1(2-ΔΔCt < 1) which indicate decreased levels of LYVE-1,VEGFR-3 and CD44 gene expression in the gastric cancer tissues.This unfortunate mistake is an important example showing how a simple error in the interpretation of relative-quantitative gene expression data may result in misleading scientific conclusions.In this letter,a brief explanation of the 2-ΔΔCt method is given.In addition,the importance of technical quality and interpretation in gene expression studies is discussed.

Polymorphisms of ICAM-1 are associated with gastric cancer risk and prognosis

AIM:To investigate the association between single nu-cleotide polymorphisms (SNPs) in intercellular adhesion molecule-1 (ICAM-1) and the risk,biological behavior and prognosis of gastric cancer (GC) in Chinese population.METHODS:The study group consisted of 332 GC patients and 380 healthy controls.Genotyping was performed using polymerase chain reaction and the results were confirmed by sequencing.The associa-tion of ICAM-1 K469E polymorphisms and the risk of GC were studied,and the correlation of ICAM-1 K469E polymorphisms with the clinicopathological parameters and prognosis of the patients with complete clinical and follow-up data was analyzed.RESULTS:Carriers of AA genotype had a significantly increased risk of GC compared with carriers of AG and GG genotypes [odds ratios:1.36;95% confidence in-terval (CI):1.01-1.84;P=0.041].GC patients with AA genotype were more prone to distant metastasis than those carrying AG and GG genotypes (18.9% vs 7.0%,respectively;P=0.002).In addition,patients at stage Ⅳ had significantly more carriers of AA genotype than those of AG and GG genotype (27.4% vs 16.9%,re-spectively;P=0.046).Follow-up study showed that the overall cumulative survival rate was 23.7% in AA geno-type group and 42.9% in AG and GG genotypes group.In univariate analysis,AA genotype was correlated with the overall cumulative survival (P=0.034).But in multi-variate analysis,ICAM-1 polymorphism was not an inde-pendent prognostic factor for the overall survival (relative risk,1.145;95% CI:0.851-1.540;P=0.370).CONCLUSION:Polymorphisms of ICAM-1 K469E can be a useful biomarker for identifying individuals with higher risk of GC,predicting disease progression,and guiding individualized treatment.

Down-regulation of STAT3 expression by vector-based small interfering RNA inhibits pancreatic cancer growth

AIM:To evaluate the effect of RNA interference (RNAi) mediated silence of signal transduction and activation of transcription (STAT)3 on the growth of human pancreatic cancer cells both in vitro and in vivo.METHODS:STAT3 specific shRNA was used to silence the expression of STAT3 in pancreatic cancer cell line SW1990.The anti-growth effects of RNAi against STAT3 were studied in vitro and in experimental cancer xenografts in nude mice.The potential pathways involved in STAT3 signaling were detected using reverse transcription polymerase chain reaction and western blotting.RESULTS:The expression of the STAT3 was inhibited using RNAi in SW1990 cells.RNAi against STAT3 inhibited cell proliferation,induced cell apoptosis and significantly reduced the levels of CyclinD1 and Bcl-xL when compared with parental and control vector-transfected cells.In vivo experiments showed that RNAi against STAT3 inhibited the tumorigenicity of SW1990 cells and significantly suppressed tumor growth when it was directly injected into tumors.CONCLUSION:STAT3 signaling pathway plays an important role in the progression of pancreatic cancer,and silence of STAT3 gene using RNAi technique may be a novel therapeutic option for treatment of pancreatic cancer.

Isolation of Main Genes Involved in Flowering of Saffron （Crocus sativus L.） in Order to Study Effective Flowering Protein

Saffron （Crocus sativus L.） always is grown for using its flowers in nutrient industry, color industry and healthy compounds due to its flowers and specially stigmas. Because of its expensive flowers, surveying and recognizing on effective genes for flowering is very important and its results can help us to control rate and timing of flowering at an early stage of flowering. The gene and gene state meant Pistillata like MADS box （PIC2） were surveyed for recognizing its molecular mechanism. The molecular sequence at the genes has high similarity to members of family MADS that is a factor for controls of protein at flowering stage. PIC2 gene was studied by bioinforrnatics resources. Primers were designed for replicating the gene and DNA and RNA were extracted from saffron＇s leaves. The gene＇s eDNA was built by recopying enzyme and used such a pattern for replicating gene PIC2 at polymerase chain reactions （PCR）. Segments were replicated such 900 eDNA pair-nucleotides and a segment such 2,100 of DNA＇s pair-nucleotides. The gene codes a protein that was composed of 210 amino acids that has MADS sequence box. Analysis of protein＇s molecular structure and homological modeling of the protein indicated that it has a regular structure.

Translocation of Polymer Through a Nanopore Studied by Langevin Dynamics:Effect of the Friction Coefficient

The driven polymer translocation through a nanopore with unbiased initial configuration has been studied by using Langevin dynamics(LD) simulations.It is found that the scaling relationship between translocation time and the polymer chain length is strongly affected by the friction coefficient in LD and the driving force.However,there is no scaling relationship between the translocation time and the friction coefficient.The translocation time is almost inversely proportional to the driving force,which is in agreement with those obtained in biased translocation.The scaling relationship between gyration radius(R g) of subchain at the trans side with the subchain length(L) is R g ～L 0.33 that is in good agreement with the limiting value for molten globule state,while the curve of R g of subchain at the cis side has two distinct stages.During translocation,the subchain at the cis side is being stretched gradually,and the structure of the subchain transforms from sphere-like to rod-like.When the effect of stretching reaches the tail end,the subchain is at the most stretched state.Finally the subchain will rapidly restore to coil structure.According to the results of force analysis,the retarding force at the trans side is more crucial during the practical translocation.

A Few Questions that Should be Clarified in the Polymerase Chain Reaction

The polymerase chain reaction is one of the most useful technical ad- vance and inventions in modern molecular biology. Developed in 1983 by Kary Mullis, PCR is now a common and indispensable technique used in medical and bi- ology research labs for a variety of applications. A large number of articles relat- ed to PCR are available on the internet and other places. People know well about the basic principle and are very familiar with the procedures of the PCR. But, some details were neglected on the numbers of the target sequence and other DNA strands number after 30 to 35 cycles of the PCR. In most papers, the number of newly synthesized DNA strands including target DNA and non target DNA is am- biguous and even wrong. In this paper, highlights were given to the theoretical number of target DNA number in details and the exact number of the target DNA number can be concluded by analysis.

女性生殖道解脲脲原体感染状况及其分群价值的研究

目的研究女性生殖道解脲脲原体（Uu）的感染状况和分群。方法选择2009年8~12月拟诊为尿道炎、阴道炎的女性患者668例为病例组,同期体检女性396例为对照组,取宫颈管分泌物同时进行Uu液体培养和固体培养,阳性标本采用PCR技术进行分群,再随机挑选部分阳性标本进行DNA测序。结果病例组Uu阳性率39.67%（265/668）,对照组Uu阳性率34.34%（136/396）,差异无统计学意义（P〉0.05）;病例组检出生物群206例（77.74%）,对照组检出生物群101例（74.26%）,差异无统计学意义（P〉0.05）;病例组Uu感染者中检出生物1群146例（占70.87%）,检出生物2群48例（占23.30%）,混合感染12例（占5.83%）,对照组Uu感染者中检出生物1群85例（占84.16%）,检出生物2群10例（占9.90%）,混合感染6例（占5.94%）,差异有统计学意义（P〈0.05）。结论健康女性泌尿生殖道可存在无症状的Uu携带状态。由于反复感染,存在未定型的解脲脲原体。Uu生物1群可能为泌尿生殖道的正常寄生微生物,而Uu生物2群可能是致病群。

采用新型压裂液技术实时控制压裂液的流变性

在对油气藏实施水力压裂强化增产处理过程中 ,实时控制压裂液的流变性是提高施工作业成功率 ,确保压裂油气井获得长效高产和提高压裂作业经济效益的有效途径。本文介绍的新型短链分子聚合物压裂液具备了流变性可实时控制的优良性能。现场应用实践证实 ,新型压裂液可在压裂液用量大幅度减少的条件下 ,明显提高作业气井的产量 ,改善气藏产状。另外 ,新型压裂液可循环再利用 。

Application of named reactions in polymer synthesis

In recent years, with the rapid development of polymer science, the application of classical named reactions has transferred from small-molecule compounds to polymers. The versatility of named reactions in terms of monomer selection, solvent environment, reaction temperature, and post-modification permits the synthesis of sophisticated macromolecular structures under conditions where other reaction processes will not operate. In this review, we divided the named reactions employed in polymer-chain synthesis into three types: transition metal-catalyzed cross-coupling reactions, metal-free cross-coupling reactions, and multi-components reactions. Thus, we focused our discussion on the progress in the utilization of these named reactions in polymer synthesis.

Blue light-emitting polyfluorenes containing dibenzothiophene-S,S-dioxide unit in alkyl side chain

Blue light-emitting polyfluorenes containing dibenzothiophene-S,S-dioxide(SO) unit in alkyl side chain(PF-FSOs and PF-CzSOs) were synthesized. All the polymers show high thermal stability with the decomposition temperatures over400 °C. The highest occupied molecular orbital(HOMO) and the lowest unoccupied molecular orbital(LUMO) energy levels of the copolymer slightly decrease with the increase of SO content in side chain. PL spectra of the polymers show slightly red shift and broadening with the increase of solvent polarities, indicating unremarkable intramolecular charge transfer(ICT) effect in the polymers containing SO unit in alkyl side chain. EL spectra of the polymers are almost unchanged in the current densities from 100 to 400 mA cm.2, indicating the superb EL stability of the resulted polymers. The EL spectra of the copolymers exhibit obvious blue-shift and narrowing with the CIE of(0.18, 0.11) for PF-FSO10 and(0.17, 0.11) for PF-CzSO10, respectively,compared with PF-SO10 containing SO unit in main chain with the CIE of(0.16, 0.17) and PFO with the CIE of(0.18, 0.18).The superior device performances were obtained with the luminous efficiency(LEmax) of 1.17 and 0.68 cd A.1 for PF-FSO15 and PF-CzSO20, respectively, compared with the LEmax of 0.37 cd A.1 for PFO. The results indicate that linking SO unit to alkyl side chain of the polyfluorene is a promising strategy for efficient blue light-emitting polymers.

Segmental dynamics near the chain end of polystyrene in its ultrathin films:a study by single-molecule fluorescence de-focus microscopy

Rotational motion of fluorophores chemically attached to polystyrene chain-ends in ultra-thin films on solid substrates was studied by single-molecule fluorescence de-focus microscopy.The collective feature of the rotational motion was found and evidenced by the sharp change of the population of fluorophores undergoing rotational motion within a very narrow temperature range(named as the changing temperature,T c).The T c value was found to depend on film thickness and interfacial chemistry and the variation of the T c value is also dependent on the molecular weight of the polymer.The results demonstrate that the spatial confinement effect enhances the segmental mobility near the polymer chain-ends while the interfacial attraction restricts the segmental motion inside the thin film.

Probing the effects of external species on poly(acrylate acid) chain dynamics by using cationic AIE-active fluorophore

We report here our results on the investigation of the chain dynamics of poly(acrylic acid) in aqueous solution. The concentration of poly(acrylic acid) was approximately 3.8×10^(-4) mol/L, two orders of magnitude higher than that reported in the literature. The p H value of the solution was 3.9, and the hydrogen bonds between the intrinsic and ionized carboxylic acid groups formed dynamic networks, which captured aggregation-induced emission-active molecules(a tetra-quaternary ammonium modified tetraphenylethene derivative) inside the polymer coils and induced fluorescence emission. The hydrogen bonds can be classified as intra- or intermolecular; both can be probed based on the emission change of the tetra-quaternary ammonium modified tetraphenylethene probes. The effects of different external stimuli on the polymer chain dynamics were investigated using different metal cations(including Na^+, Li^+, Zn^(2+), Ni^(2+), Ca^(2+), and Co^(2+)), different cation concentrations(1×10^(-6) to 4×10^(-4) mol/L), different poly(acrylic acid) molecular weights(5, 240, and 450 k Da), and different copolymers. The experimental results indicate that the long poly(acrylic acid) chains(high molecular weight) tend to form dense globular coils and exclude the probe molecules outside, which are robust and unsusceptible to water-soluble metal cations. However, the shorter poly(acrylic acid) chains tend to form intermolecular hydrogen bonds, which are helpful in capturing more probe molecules inside the networks, thus inducing stronger emission. Because of the dual functions of forming hydrogen bonds with carboxylic groups and acting as an acceptor of protons from the carboxylic acid group to form cationic species, copolymerization with acrylate amide [poly(acrylic acid)-co-poly(acrylamide)] can greatly affect the chain dynamics of poly(acrylic acid) segments, which is reflected by the drastically decreased emission intensity from the fluorescent probes.

Side-chain fluorination on the pyrido[3,4-b]pyrazine unit towards efficient photovoltaic polymers

A series of new polymer donors (PT-PP, PT-2fPP and PT-4fPP) were synthesized based on alkylthiophene substituted benzodithiophene (BDT-T) and pyrido[3,4-b]pyrazine (PP) building blocks and the effects of fluorination on the polymer properties were explored. Photophysical properties, charge mobilities and morphologies of the three polymers have been intensively investigated. The results indicated that the introduction of the fluorine atom at meta-positions of phenyl substituted PP unit hardly affected their highest occupied molecular orbital (HOMO) level. More importantly, controlling the degree of side-chain fluorination in the polymers is crucial for optimizing the blend morphology. Three polymers showed different photovoltaic properties. The polymer solar cell (PSC) based on the single layer device structure of ITO/PEDOT:PSS/PT-4fPP:PC71BM (1:1, w:w)/ZrAcac/Al demonstrates a high power conversion efficiency (PCE) of 7.61% under the illumination of AM 1.5G,100 mW cm-2, which is the highest value for PP-based PSCs.