微量锗分析测定的研究进展

主要梳理了近年来微量锗测定分析方法研究的进展情况,从微量锗样品原料的前期处理工作开始介绍,对各种微量锗的测定分析方法进行分析和研究,其中包括极谱法、光度吸光法、原子光谱吸收法等测定分析方法,同时对各种方法进行了有针对性的总结评述,并对微量锗测定分析方法的未来发展加以展望.     

水中悬浮物分析方法的改进

采用不同分析方法对水中悬浮物进行对比试验,对不同分析样品找出最佳分析方法,对重量法和仪器法以及不同仪器之间的对比进行了分析并提出了改进方法。     

烟草中痕量金属元素分析方法的研究进展

综述了近年来烟草中痕量金属元素分析方法的研究进展。探讨了样品的前处理技术,并对原子光谱法、分子光谱法、离子色谱法等方法进行了归纳和评述;展望了烟草中痕量金属元素分析方法的研究方向和发展前景。     

硅烷的纯化技术与检测分析方法

高纯硅烷主要用于电子和半导体行业中,是一系列含硅化合物的基本原料。概述了硅烷的纯化技术和分析方法。纯化技术有吸附法、冷冻法、精馏法;检测分析方法包括DID、PDHID气相色谱分析仪和气相色谱—质谱联用分析仪。     

茶叶中痕量铅分析方法的研究进展

综述了近年来茶叶中痕量铅分析方法的研究进展.从原子光谱法、分子光谱法、电化学分析法等方法进行了归纳和评述;展望了茶叶中痕量铅分析方法未来的研究方向和发展前景.     

做好石化企业经济分析,努力增加经济效益

企业经济分析是企业生产经营优化和提高经济效益的基础。石化企业是典型的流程型工业,其经济分析方法不同于离散型行业。石化企业常用的经济分析方法有边际贡献法、净产出法及线性规划模型法。结合作者多年工作经验,介绍了这些分析方法在应用过程中的易出现问题及注意事项,供石化行业生产经营计划及优化管理人员借鉴。     

几种有限元分析方法在机头流道分析中的应用研究

研究了 3种有限元分析方法———流函数法、侧壁因子修正法和全高三棱柱单元法在挤出机平板机头流道分析中的应用情况。结果表明 ,流函数法只适合分析流道高度不变化或变化极小的情况 ;侧壁因子修正法误差较小 ;全高三棱柱单元法比较精确 ,但分析方法复杂     

纺丝油剂用磷酸酯类单体分析方法

介绍了用于纺丝油剂用磷酸酯类单体的混合指示剂法、电位滴定法、核磁共振法、色谱法等分析方法,表述了各方法的优缺点,指出结合多种分析方法对该类单体进行分析是今后实现其结构和组成定量分析的方向。     

非甾体抗炎药修饰查尔酮衍生物的制备和表征

长期服用非甾体抗炎药会给患者带来严重的副作用,如胃肠道出血、心血管疾病等。受查尔酮生物活性多样性的启发,本文以非甾体抗炎药（阿司匹林、布洛芬、萘普生、甲灭酸、氟灭酸、依托度酸、吲哚美辛）和查尔酮为原料,EDCI为缩合剂,DMAP为催化剂,经酯化反应得到7种查尔酮衍生物,产物的收率为67%～86%。     

煤及其燃烧产物中无机组分分析方法比较

从三个方面对煤及其燃烧产物中无机组分的分析方法进行了比较和评价：1)比较和评价了煤及其燃烧产物中矿物分析方法，其中主要讨论了XRD法和CCSEM法；2)比较和评价了煤及其燃烧产物中元素含量的分析方法，主要包括X-射线和v-射线技术；原子吸收或发射技术(AAS／AES)和质谱法(MS)；3)比较和评价了煤及其燃烧产物中微量元素的赋存形态分析方法，主要包括直接分析方法和间接分析方法．     

In-situ monitoring of pharmaceutical and specialty chemicals crystallization processes using endoscopy–stroboscopy and multivariate image analysis

This contribution presents the proof of concept of endoscopy–stroboscopy based in situ low-cost imaging of crystallization processes. This low-cost sensor currently is widely spread in the field of medical diagnosis of human vocal chords and this work presents its application in the context of pharmaceutical and chemical crystallization process monitoring. The model compounds used in this study are the active pharmaceutical ingredient (API) flufenamic acid and citric acid.     

Development of molecularly imprinted co-polymeric devices for controlled delivery of flufenamic acid using supercritical fluid technology

This work reports the development of a novel class of affinity co-polymeric materials using supercritical fluid technology. Polymeric materials with molecular recognition to flufenamic acid, were first synthesized in supercritical carbon dioxide (scCO₂) using the drug as template. Molecularly imprinted co-polymers of methacrylic acid (MAA) or N-isopropyl acrylamide (NIPAAm) crosslinked with ethylene glycol dimethacrylate (EGDMA) were synthesized using different crosslinking degrees and template:monomer ratios, at 65 °C and 21 MPa. High-pressure NMR experiments confirmed that the nature of the interactions between the drug and the functional monomers during the polymerization step are mainly hydrogen bonds. scCO₂-assisted impregnation revealed that the imprinted matrices were able to uptake higher amounts of flufenamic acid. This effect was particularly evidenced in the more crosslinked matrices, with P(MAA-EGDMA) imprinted copolymers binding up to 101.5 mg drug/g polymer against only 50.5 mg/g in the non-imprinted copolymer. In vitro drug delivery experiments showed that imprinted co-polymers release the drug in a more sustained way than the corresponding non-imprinted matrices. Overall it was shown that supercritical fluid technology is a viable approach for the development of self-assembly molecular recognition polymers with potential application in controlled drug delivery systems.     

Effect of 2-Hydroxypropyl-β-cyclodextrin on Solubility of Sparingly Soluble Drug Derivatives of Anthranilic Acid

Guest-host complex formation of three drug derivatives of anthranilic acid, mefenamic acid, niflumic acid, and flufenamic acid with 2-hydroxypropyl-β-cyclodextrin (2HP-β-CD) in aqueous solutions was investigated using "Phase solubility study" with UV-vis spectrophotometry. Solubility of sparingly soluble drugs has been improved by addition of 2HP-β-CD at two temperatures 298.15 K and 310.15 K and two pH values 2 and 7. The influence of different 2HP-β-CD concentration on solubility of drugs at different pH and temperatures has been investigated. The 2HP-β-CD-drug complex stability constants (K(s)), and dissociations constants (K(d)), as well as the thermodynamic parameters of reaction, i.e., the free energy change (ΔG), the enthalpy change (ΔH) and the entropy change (ΔS), were determined. The experimental data indicated formation of 1:1 inclusion complexes, which were found effective binders increasing the solubility of drugs.     

Dopamides,Vanillylamides, Ethanolamides,and Arachidonic Acid Amides of Anti‐inflammatory and Analgesic Drug Substances as TRPV1 Ligands

Drug substances can be acylated metabolically to give derivatives with specific and strong molecular effects. We generated potentially naturally occurring acid amides of several anti‐inflammatory and analgesic drugs. In the amides, the drug moieties served either as amine or acid components. All compounds were evaluated for activity toward transient receptor potential vanilloid subfamily member 1 (TRPV1) in a cell‐based Ca²⁺ influx assay; TRPV1 is a key receptor in the pain pathway and a promising target for analgesic drugs. We found that dopamine amides of fenamic acids have TRPV1 agonist activity in the nanomolar range, and that the arachidonoyl amide of a dipyrone metabolite has TRPV1 antagonist activity. Flufenamic acid dopamide, the most potent TRPV1 agonist reported herein, retains the cyclooxygenase (COX) inhibition properties of the parent compound flufenamic acid. Thus it acts on two different major players in the pain processing machinery. The compounds could be further keys to understanding the mechanism of action of fenamates and dipyrone at the molecular level. The fenamic acid dopamine amides qualify as new lead structures for drug development.     

NMR-Guided Repositioning of Non-Steroidal Anti-Inflammatory Drugs into Tight Junction Modulators

Bioavailability is a major bottleneck in the clinical application of medium molecular weight therapeutics, including protein and peptide drugs. Paracellular transport of these molecules is hampered by intercellular tight junction (TJ) complexes. Therefore, safe chemical regulators for TJ loosening are desired. Here, we showed a potential application of select non-steroidal anti-inflammatory drugs (NSAIDs) as TJ modulators. Based on our previous observation that diclofenac and flufenamic acid directly bound various PDZ domains with a broad specificity, we applied solution nuclear magnetic resonance techniques to examine the interaction of other NSAIDs and the first PDZ domain (PDZ1) of zonula occludens (ZO)-1, ZO-1(PDZ1). Inhibition of ZO-1(PDZ1) is expected to provide loosening of the epithelial barrier function because the domain plays a crucial role in maintaining TJ integrity. Accordingly, diclofenac and indomethacin were found to decrease the subcellular localization of claudin (CLD)-2 but not occludin and ZO-1 at the apicolateral intercellular compartment of Madin–Darby canine kidney (MDCK) II cells. These NSAIDs exhibited 125–155% improved paracellular efflux of fluorescein isothiocyanate insulin for the Caco-2 cell monolayer. We propose that these NSAIDs can be repurposed as drug absorption enhancers for peptide drugs.     

硬脂酸柱撑类水滑石的制备及应用

采用离子交换法制备了硬脂酸柱撑类水滑石,并用红外光谱分析对其进行了表征.通过HAAKE流变仪、颜色测定仪研究了硬脂酸柱撑类水滑石与钙锌热稳定剂并用时的热稳定性,重点考察了水滑石的结构对PVC稳定性能的影响.结果表明硬脂酸柱撑类水滑石与钙皂/锌皂复配显著改善了PVC热老化过程中的初期着色性.     

硬脂酸柱撑类水滑石的制备及应用

采用离子交换法制备了硬脂酸柱撑类水滑石,采用红外光谱分析对其结构进行了表征。通过HAAKE流变仪、颜色测定仪研究了硬脂酸柱撑类水滑石与钙锌热稳定剂并用时的热稳定性,重点考察了水滑石的结构对PVC稳定性能的影响。结果表明硬脂酸柱撑类水滑石与钙皂/锌皂复配显著改善了PVC热老化过程中的初期着色性。     

Processing triacetyl-β-cyclodextrin in the liquid phase using supercritical CO2

TA-β-CD has been proposed as an effective sustained release carrier for highly water soluble drugs with short biological half-lives. In this work, the possibility of preparing drug - triacetyl-β-cyclodextrin (TA-β-CD) complexes in the liquid phase by exploring its solid-liquid-gas equilibrium (S-L-G) under supercritical CO₂ atmosphere was evaluated. The S-L-G equilibrium line for the binary system TA-β-CD + CO₂ was determined by a visual method for pressures up to 25.3 MPa. At the studied conditions, a homogeneous and translucent liquid phase emerge at 307 K when exposed to CO₂ pressurized at 16 MPa and this temperature further increases with increasing pressure, up to 318 K at 25.3 MPa. The S-L-G equilibrium behaviour observed is typical of this kind of asymmetric systems, it is totally CO₂ density-dependent and opens the possibility of further processing TA-β-CD in the liquid phase. In order to investigate the possibility of preparing a drug-TA-β-CD complex in the liquid phase of TA-β-CD, a preliminary experiment was performed at 25 MPa and 308 K using flufenamic acid (FA) as the model active principle.     

NMR spectroscopy as basis for characterization of Pluronic® F108 and its derivatives

The hydroxyl end groups of Pluronic®F108 {a triblock copolymer surfactant of poly(ethylene glycol) and poly(propylene glycol) [PEG‐PPG‐PEG]} were modified into primary amine, sulfonic acid, and quaternary ammonium equivalents for use in affinity chromatography. NMR was used for monitoring the efficacy of modifications on intermediaries and final products. The primary amine equivalents were prepared via conversion of the hydroxyl groups to a tosylate, its displacement with an azide, followed by reduction to the primary amine. The sulfonic acid equivalents were prepared via hydroxyl group tosylation, the displacement of tosylate with thiol, and its oxidation to sulfonic acid. The conversion to trimethyl ammonium was achieved via hydroxyl group tosylation, tosylate displacement by halide, and halide displacement with trimethylamine. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 109–117, 2000