SYNTHESIS OF ADENOSINE DERIVATIVES WITH CARBOXYALKYL SIDE CHAIN AT 2',3'OR 5'POSITION

Some nucleoside carhoxylic acid derivatives,such as(±)ethyl ester of griseolic acid (4)and 9-(2'-deoxy-2'-(benzyloxycarbonyl)-methylene-β-D-rihohept-2'-enofuranosyluranate)adenine (11),were synthesized.The formation of lactone of 5'-deoxy-adenosineacetic acid(AAA,3)was investigated by using different reagents for lactonization from AAA,but all of the efforts failed, and sone unexpected compounds were obtained.

Infrared Photodissociation Spectroscopic and Theoretical Study of the HC2nO+（n=3-6） Cations

The carbon chain cations, HC2nO+(n=3-6) are produced via a pulsed laser vaporization supersonic expansion ion source in the gas phase. Their infrared spectra are measured via mass-selected infrared photodissociation spectroscopy of the CO “tagged”[HC2nO·CO]+ cation complexes in 1600-3500 cm-1 frequency range. The geometric and electronic structures of the [HC2nO·CO]+ complexes and the core HC2nO+(n=3-6) cations are determined with the aid of density functional theory calculations. These HC2nO+(n=3-6) ions are identified to be linear carbon chain derivatives terminally capped by hydrogen and oxygen. The triplet ground states are 10-15 kcal/mol lower in energy than the singlet states, indicating cumulene-like carbon chain structures.

The Traveling Wave Solutions of Space-Time Fractional Differential Equation Using Fractional Riccati Expansion Method

In this paper, we firstly give a counterexample to indicate that the chain rule is lack of accuracy. After that, we put forward the fractional Riccati expansion method. No need to use the chain rule, we apply this method to fractional KdV-type and fractional Telegraph equations and obtain the tangent and cotangent functions solutions of these fractional equations for the first time.

Counterexample of Local Fractional Order Chain Rule and Modified Definition of Local Fractional Order

Fractional calculus is a powerful tool for modeling nonlinear systems.It is necessary to discuss the basic properties of fractional order before solving a fractional order model.Using the formula of power function defined by local fractional derivative and the chain rule to calculate a compound function,the results are inconsistent.This shows that the chain rule of local fractional derivatives similar to classical calculus is suspicious,and fractional complex transformation based on the chain rule is also suspicious and needs further discussion.In order to overcome this inconsistency,an improved definition of local fractional derivative,which can be regarded as a fractal derivative,is proposed based on the results derived from the relationship between the mass function and the Hausdorff measure.

Identification and Characterization of Genes Responsible for Drought Tolerance in Rice Mediated by Pseudomonas fluorescens

Drought is one of the major abiotic stresses which adversely affect crop plants limiting growth and yield potential.Structural and functional characterization of drought stress-induced genes has contributed to a better understanding of how plants respond and adapt to the drought stress.In the present study,differential display technique was employed to study the gene expression of rice plants at the reproductive stage that were subjected to drought stress by withholding water,Pseudomonas fluorescens strain(Pf1) treated plants subjected for drought stress by withholding water and control(well-watered).Differentially expressed c DNAs of six genes(COX1,PKDP,b ZIP1,AP2-EREBP,Hsp20 and COC1) were identified,cloned and sequenced.Real-time q PCR analysis showed that all the six genes were upregulated in drought-stressed plants treated with Pf1.This revealed that the remarkable influence of Pf1 colonization leads to drought tolerance at the reproductive stage.These results showed that high levels of gene expression in plants lacking adequate water can be remarkably influenced by Pf1 colonization,which might be a key element for induced systemic tolerance by microbes.

Minor change in the length of carbon chain has a great influence on the antitumor effect of paclitaxel-fatty alcohol prodrug nanoassemblies:Small roles,big impacts

Prodrug-based nanoassembly emerges as a hopeful way for the efficient delivery of antitumor drugs,with carrier-free structure and ultra-high drug loading.Carbon chains are widely used to design self-assembling prodrugs.The impacts of the length of carbon chains on the self-assembly stability,drug delivery efficiency and antitumor effect of prodrugs have not been fully elucidated.Here,three paclitaxel prodrugs were synthesized by conjugating paclitaxel with octanol(C_(8)),decanol(C_(10))or dodecanol(C_(12))through disulfide bond.The three prodrugs could form homogeneous nanoparticles,with over 50%drug loading and redox dual-responsivity.Interestingly,the length extension of carbon chains ameliorates the self-assembly and the colloidal stability of prodrugs,thus improving the drug delivery efficiency.The optimal paclitaxel-dodecanol prodrug nanoassemblies exhibit better antitumor efficacy than Taxol and Abraxane.These findings are meaningful for the rational design of advanced nanomedicines in cancer therapy.

Effects of Taxotere on invasive potential and multidrug resistance phenotype in pancreatic carcinoma cell line SUIT-2

INTRODUCTIONDevelopment of drug-resistance to chemotherapyand subsequent metastasis of tumor are primarilyresponsible for treatment failure and the death fromcancer. There have been many previous studies onthe relationship between expression of multidrugresistance (MDR) phenotype P-glycoprotein (P-gp)and the malignant properties of tumors, but theresults are often conflicting[1-8]. The difference intumor types or MDR phenotype induced by specificagents might account for this discrepancy. Taxotere(TXT), a member of the family of taxanes, hasantitumor activity through its effect of promotingthe polymerization of tubulin[9,10].

Effects of the number of imidazoline ring and the length of alkyl group chain of imidazoline derivatives on corrosion inhibition of carbon steel in HCl solution:Molecular simulation and experimental validation

The effects of the number of imidazoline ring and the length of alkyl group chain of imidazoline derivatives were investigated using quantum chemical calculation,molecular dynamics simulation and experimental techniques.Three corrosion inhibitors including symmetrical lauric acid imidazoline(SAI),tetracyclic lauric acid imidazoline(LAI),and symmetric stearic acid imidazoline(SPI)were synthesized and their inhibition performance was evaluated using weight loss measurement,electrochemical techniques and surface characterization.The results show that SAI and LAI with the same length of alkyl group chain,LAI with more imidazoline rings could supply a better inhibition performance since the increase of active sites.The increase of active sites attached to the metal surface may also change the distribution of corrosion inhibitor,which could limit inhibition performance improvement.While,SAI and SPI with the same number of imidazoline rings,SPI with longer alkyl group chain shows a better inhibition efficiency due to the better hydrophobic performance of alkyl groups.Among the three inhibitors,SPI shows the best inhibition performance,indicating that the alkyl group chain length affects the inhibition performance more obvious than the number of the imidazoline rings.

Expression and functional characterization of platelet-derived growth factor receptor-like gene

AIM:To investigate the role of platelet-derived growth factor receptor-like gene(PDGFRL)in the anti-cancer therapy for colorectal cancers(CRC).METHODS:PDGFRL mRNA and protein levels were measured by reverse transcription-polymerase chain reaction(RT-PCR)and immunohistochemistry in CRC and colorectal normal tissues.PDGFRL prokaryotic expression vector was carried out in Escherichia coli(E.coli),and purified by immobilized metal affinity chromatography.The effect of PDGFRL protein on CRC HCT-116 cells was detected by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide(MTT),clone counting,cell cycle,and wound healing assay.RESULTS:Both RT-PCR and immunohistochemistry showed that the expression of PDGFRL in colorectal normal tissues was higher than in cancer tissues.Recombinant pET22b-PDGFRL prokaryotic expression vector was successfully expressed in E.coli,and the target protein was expressed in the form of inclusion bodies.After purification and refolding,recombinant human PDGFRL(rhPDGFRL)could efficiently inhibit the proliferation and invasion of CRC HCT-116 cells detected by MTT,clone counting and wound healing assay.Moreover,rhPDGFRL arrested HCT-116 cell cycling at the G0/G1 phase.CONCLUSION:PDGFRL is a potential gene for application in the anti-cancer therapy for CRC.

Sensitivity Analysis of Radial Basis Function Networks for River Stage Forecasting

Sensitivity analysis of neural networks to input variation is an important research area as it goes some way to addressing the criticisms of their black-box behaviour. Such analysis of RBFNs for hydrological modelling has previously been limited to exploring perturbations to both inputs and connecting weights. In this paper, the backward chaining rule that has been used for sensitivity analysis of MLPs, is applied to RBFNs and it is shown how such analysis can provide insight into physical relationships. A trigonometric example is first presented to show the effectiveness and accuracy of this approach for first order derivatives alongside a comparison of the results with an equivalent MLP. The paper presents a real-world application in the modelling of river stage shows the importance of such approaches helping to justify and select such models.

肉制品中马源性成分重组酶介导链置换等温扩增实时检测方法的建立及应用

目的:建立一种快速鉴定肉及肉制品中马源性成分的重组酶介导链置换等温扩增实时检测方法。方法:以马源性ATpase 6基因为靶基因设计多组特异性引物和Exo探针,通过引物筛选及反应参数优化,建立一种采用重组酶介导链置换等温扩增技术检测马源性成分的方法,并对该方法进行特异性、灵敏度和稳定性验证,同时通过对不同掺入比例混合样品、不同加工工艺模拟样品和市售样品进行检测,分析方法的检出限、适用性和准确性。结果:该方法反应迅速、特异性强、灵敏度高。可在39℃恒温条件下16min内完成反应;对23种非目标源性具有良好特异性;目标DNA的检测灵敏度可达到1.8copies/μL水平;对生肉的检出限为0.01%(质量分数,下同),对熟肉制品的检出限为0.1%;对90份市售样品进行检测,结果与标准方法一致。结论:建立的重组酶介导链置换等温扩增方法可用于肉及肉制品中马源性成分的掺假鉴别检测。

Association Study of Thyroid Papillary Carcinoma with Depression and BDNF Expression

Objective: To analyze the correlation between Val66Met gene of brain-derived neurotrophic factor (BDNF) and papillary thyroid carcinoma (PTC) complicated with depression. To evaluate the clinical value of papillary thyroid carcinoma. Methods: Self-rating Anxiety Scale (SAS) and Self-rating Depression Scale (SDS) were used to assess the correlation of BDNF in the blood of patients with depressive disorder of thyroid papillary carcinoma using polymerase chain reaction PCR. The relationship between BDNF gene polymorphism and the incidence of thyroid papillary carcinoma was analyzed, and the susceptibility factors of thyroid papillary carcinoma complicated with depression were explored. Results: Compared with normal control group, T3 and T4 of PTC in non-depressed group were decreased, while TSH and TPOAb were increased (P < 0.05). Compared with normal control group, T3, T4 and TPOAb were increased and TSH was decreased in PTC depression group (P < 0.05). PTC depression score was higher than that of healthy control group (P < 0.05), and PTC combined depression score was higher than that of normal control group (P < 0.05). The depression rate of PTC combined with depression was 86.7%, which was higher than that of other groups (P < 0.05). The distribution of RS6265 locus genotype of BDNF gene was significantly different between PTC with depression group and PTC without depression group (P Conclusion: There is a significant difference between PTC with depression and PTC without depression, which is related to SNP rs6265 of BDNF gene. AG and GG are both risk sites of PTC with depression, and GG type is more prone to PTC with depression.

C_(3)产业链高质量发展研究及建议

分析预测了我国丙烯及其衍生物聚丙烯、丙烯腈、丙烯酸、苯酚/丙酮、环氧丙烷、丁辛醇等的市场供需情况;指出了我国C_(3)产业链产能全面过剩的原因;提出了新形势下进入C_(3)产业链的切入点、高质量发展建议。

共情与狂欢:“卡塔尔小王子”形象传播策略

2022卡塔尔世界杯第一次在北半球冬季的阿拉伯地区举办。世界杯的举办不仅向全球展示了阿拉伯文化,而且塑造了全新的卡塔尔国家形象。世界杯开幕期间,“卡塔尔小王子”形象暗合体育赛事中吉祥物兼具本土与全球的特征,在场景建构、迷因扩散、互动仪式链构型、审美共通等方面引发了情感共鸣与网络狂欢,从文化共性探寻、媒体奇观构建、整合碎片化传播的角度,为降低文化折扣和以柔性传播的方式实现文明交流互鉴、建构国家形象提供启示。

紫杉醇外泌体的载药工艺优化及体外抗肿瘤作用研究

目的优化紫杉醇(PTX)外泌体给药系统的载药工艺并评价其有效性和安全性,为开发新型抗肝癌制剂提供依据。方法采用超速离心法提取骨髓间充质干细胞外泌体(BMSCs-Exo);电穿孔法包载紫杉醇,以药物包封率作为评价指标,通过响应面法优化载药工艺;高效液相色谱法测定紫杉醇外泌体(Exo-PTX)的载药量及考察释药行为;CCK-8法检测Exo-PTX对肝癌细胞HepG2增殖的抑制作用;溶血实验评价Exo-PTX的安全性。结果Exo-PTX的最佳电穿孔法载药工艺条件为:PTX药物浓度81.80μg·mL^(-1)、电压0.6 mV、电击次数8次,Exo-PTX的平均包封率为(22.38±0.08)%。同时Exo-PTX具有良好的缓释性能,且在微酸性的肿瘤微环境下可加速释放,在模拟正常体液和肿瘤环境下,48 h时的累计释放度分别为(49.35±0.67)%、(61.94±0.43)%。Exo-PTX对体外HepG2细胞具有显著的抑制作用且无溶血风险。结论在最佳载药工艺条件下制备的Exo-PTX具有较好的体外抗肝癌作用,并呈明显的浓度依赖性,缓释性良好,为PTX制剂的二次开发提供了依据。

噬菌肽SEYT4对食品链中常见致病菌的清除效果

为探究噬菌肽在食品加工链中的应用前景,以1种含有37个氨基酸的新型噬菌肽SEYT4为研究对象,分析其结构特性,并选择食品加工链中常见的致病细菌,在不同温度、盐度及pH下进行杀菌试验,测定SEYT4的杀菌谱、杀菌效率及杀菌特性,利用C57BL/6雌性小鼠评估SEYT4的安全性,并通过模拟被致病菌污染的叶菜和厨具,探究SEYT4清除食品链中致病菌的效果。结果显示:噬菌肽SEYT4是1个发夹状的双α-螺旋结构,分子质量约为4.5ku,理论等电点为9.69;能够清除大多数高毒性且耐药的革兰氏阳性和革兰氏阴性致病菌,杀菌率高达99.99%,在不同温度下均具有较高活性,且在中性和弱碱性环境下杀菌效果更好,但在高盐环境下会失活;对小鼠红细胞无溶血作用;在构建的人工污染香菜模型中能将叶片和洗涤液中的致病菌清除约90.00%,同时能清除食品接触面上99.00%以上的致病菌。结果表明,噬菌肽SEYT4是一种对致病菌有良好的杀菌效果且安全性高的新型抗菌肽,能够有效防控食品链中污染的致病菌,有望成为一种食品加工链中的实用消毒剂。

侧链衍生季铵盐型氯胺的合成及抗菌应用

以5,5-二甲基海因(DMH)为原料,设计合成了一系列侧链衍生的季铵盐型氯胺抗菌剂(10-14),表征了前体和氯胺结构。以大肠杆菌(E.coli)和金黄葡萄球菌(S.aureus)为模式菌株,以三甲基季铵盐氯胺1为对照,初步测试了氯胺10-14的抗菌活性。结果表明,氯胺10-13抗菌能力随侧链变长先增强后减弱,其中三丁基季铵盐氯胺12对S.aureus和E.coli的杀灭对数(KL)值分别为1.07±0.09和6.49,表现出这一系列中相对更优的抗菌活性,这可能是12达到了分子触杀所需的最佳亲疏水平衡状态,与菌体细胞膜作用更强所致。此外,携羟乙基侧链氯胺14实现了对S.aureus和E.coli全杀,展现了10-14中最出色的抗菌性能,这可能和氯胺分子更易穿透菌体细胞膜有关。本工作制备的一系列高活性季铵盐氯胺抗菌剂,为更高效离子型氯胺抗菌剂的设计研发提供了参考借鉴。

宏基因组二代测序在实体器官移植感染防控中的应用

器官移植已成为多种终末期疾病的有效治疗手段,但器官移植受者术后需长期服用免疫抑制药,导致免疫功能低下,使得细菌、病毒和真菌感染的发生率相对较高。以病原学培养、免疫学检测和聚合酶链反应为代表的传统微生物检测方法被广泛用于感染检测,但存在耗时长、需预先假定病原体等问题。宏基因组二代测序由于具有病原体检出率高、对病原谱检测全面的优点,近年来被广泛应用于器官移植领域的感染防控。本文就宏基因组二代测序技术在实体器官移植感染防控上的应用现状进行综述,以期对移植相关感染的诊断和治疗提供参考。

多重实时荧光定量聚合酶链式反应在芝麻酱掺假鉴别中的应用

目的研究基于分子生物学技术,建立多重实时荧光定量聚合酶链式反应(polymerase chain reaction,PCR)技术检测芝麻酱中的植物源性成分,实现芝麻酱的快速掺假鉴别,突破单标准单物种检测的局限性。方法该研究以芝麻2S albumim mRNA基因、花生Ara b2基因、大豆Lectin基因、玉米adh1基因设计特异性引物和探针,优化反应体系,建立多重实时荧光定量PCR技术检测芝麻酱中的芝麻源性成分、花生源性成分、大豆源性成分、玉米源性成分,并应用于市售的芝麻酱样本检测分析。结果该方法高效低成本,特异性好,对小米、绿豆等10种非目标源性成分无特异性扩增;对芝麻源性成分、花生源性成分、大豆源性成分、玉米源性成分的最低检出限为100 pg/μL,具有较高的灵敏度;应用建立的方法,对市售21份芝麻酱样本进行检测分析,检测结果与标签标注不符合的有4份,标签标注符合率为80.95%,与参比方法检测结果一致。结论建立的多重实时荧光定量PCR技术对加工成品的检测具有较好的适用性,为芝麻酱的掺假鉴别提供了一种新的分子生物学方法。

产业链视角下网约车衍生广告商业模式研究

网约车市场竞争日趋加剧,各方盈利水平快速下降,衍生广告业务将成为平台、车辆持有方、司机的重要利润增长点。本文通过梳理网约车衍生广告产业链及其中各利益相关方关系,介绍并分析四种传统网约车衍生广告模式优劣势,引出新的互联网车载屏模式。该模式能够合理关切各方诉求,具有较强的可复制性、较低的边际成本。这一模式在解决行业初期面临的高投入、低可控度、低产品效能、低市场认可度等问题后,有望成为主流网约车衍生广告模式。