Epoxy acrylic resin experimental analysis of runaway reaction

Journal of Thermal Analysis and Calorimetry - Epoxy acrylic resin (EAR) has been widely used in the chemical industry for many years. However, its potential hazard is still to be ascertained....     

Polar Metabolites from the Actinobacterium Isoptericola chiayiensis Isolated from Mangrove Soil

Chemistry of Natural Compounds -     

Bis-conjugation of Bioactive Molecules to Cisplatin-like Complexes through (2,2′-Bipyridine)-4,4′-Dicarboxylic Acid with Optimal Cytotoxicity Profile Provided by the Combination Ethacrynic Acid/Flurbiprofen

A facile route to Pt^II complexes doubly functionalized with bioactive molecules through a bipyridine-type ligand is described. Initially, ligands L ^EE (containing two ethacrynic acid units), L ^EF (ethacrynic acid+flurbiprofen) and L ^EB (ethacrynic acid+biotin) were obtained in moderate to good yields from 2,2′-bipyridine-4,4′-dicarboxylic acid. Subsequent reaction of the ligands with [PtCl₂(DMSO)₂] afforded complexes [PtCl₂( L ^EE )] ( 2 ), [PtCl₂( L ^EF )] ( 3 ) and [PtCl₂( L ^EB )] ( 4 ) in high yields. All compounds were fully characterized by analytical and spectroscopic methods. Complexes 2 – 4 are highly stable in water/DMSO solution at 37 °C after 72 h, whereas progressive release of the bioactive fragments was detected in a cell culture medium. The compounds were assessed for their in vitro antiproliferative activity towards tumorigenic A2780, A2780cisR and Y79 cells and non-tumourigenic HEK293 cells. In particular, the combination of ethacrynic acid and flurbiprofen in 3 overcomes cisplatin-based resistance and provides strong cancer cell selectivity. Enzyme inhibition assays on human GST P1 and human COX-2 and cross-experiments with complex 1 , analogous to 2 – 4 but lacking bio-groups, revealed a clear synergy between the Pt^II frame and the bioactive organic components.     

Alkaline-developable and negative-type photosensitive polyimide with high sensitivity and excellent mechanical properties using photo-base generator

An alkaline developable and negative-type PSPI with a high sensitivity and excellent mechanical properties based on a poly(amic acid) (PAA) and a photo-base generator has been developed. The PAA was prepared by the polycondensation of p-phenylenediamine (PDA) with an equimolar of 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) and 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6-FDA) and converted thermally to the corresponding polyimide, PI(PDA-BPDA/6-FDA). PI(PDA-BPDA/6-FDA) showed the high thermal and mechanical properties and the dimensional stability such as the thermal decomposition temperature of 530°C, glass transition temperature of 369°C, linear coefficient of thermal expansion of 28 ppm/K, ultimate tensile strength of 148 MPa, elongation at break of 25% and dielectric constant of 2.8. The PSPI was formulated directly from PAA(PDA-BPDA/6-FDA) with a photo-base generator (PBG), (E)-3-(2-hydroxy-4-methoxyphenyl)-1-(piperidin-1-yl)prop-2-en-1-one (HMPP) (10 wt% to PAA) and the optimized parameters for photolithographic process were investigated including the PBG content, post-exposure bake (PEB) temperature, and PEB time. The PSPI based on PAA(PDA-BPDA/6-FDA) and HMPP (10 wt% to PAA) showed a sensitivity of 114 mJ/cm² and contrast of 1.29 when exposed to 365-nm light (i-line), post-exposure baked at 160°C for 5 min, and developed with an aqueous solution of 2.38 wt% tetramethylammonium hydroxide and iso-propanol. A clear negative 8-μm features pattern was obtained by contact-printing and converted into the PI pattern upon heating at 250°C, confirming by scanning electron microscopy and infrared spectroscopy.     

Effects of amorphous poly(3‐hexylthiophene) on active‐layer structure and solar cells performance

A key challenge to the development of polymer‐based organic solar cells is the issue of long‐term stability, which is mainly caused by the unstable time‐dependent morphology of active layers. In this study, poly(3‐hexylthiophene) (P3HT)/[6,6]‐phenyl C60‐butyric acid methyl ester (PCBM) blend is used as a model system to demonstrate that the long‐term stability of power conversion efficiency can be significantly improved by the addition of a small amount of amorphous regiorandom P3HT into semicrystalline regioregular one. The optical properties measured by UV–vis absorption and photoluminescence reveal that regiorandom P3HT can intimately mix with PCBM and prevent the segregation of PCBM. In addition, X‐ray scattering techniques were adopted to evidence the retardation of phase separation between P3HT and PCBM when regiorandom P3HT is added, which is further confirmed by optical microscopy that shows a reduction of large PCBM crystals after annealing at high temperature in the presence of regiorandom P3HT. The improvement of the long‐term stability is attributed to the capability of amorphous P3HT to be thermodynamically miscible with PCBM, which allows the active layer to form a more stable structure that evolves slower and hence decelerates the device decay. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 975–985     

Secondary Metabolites from the Actinobacterium Amycolatopsis taiwanensis

Chemistry of Natural Compounds -     

Thin Film Growth of 3D Sr-based Metal-Organic Framework on Conductive Glass via Electrochemical Deposition

Integration of metal-organic frameworks (MOFs) as components of advanced electronic devices is at a very early phase of development and the fundamental issues related to their crystal growth on conductive substrate need to be addressed. Herein, we report on the structural characterization of a newly synthesized Sr-based MOF {[Sr(2,5-Pzdc)(H₂O)₂] ⋅ 3 H₂O}_n ( 1 ) and the uniform crystal growth of compound 1 on a conducting glass (fluorine doped tin oxide (FTO)) substrate using electrochemical deposition techniques. The Sr-based MOF 1 was synthesized by the reaction of Sr(NO₃)₂ with 2,5-pyrazinedicarboxylic acid dihydrate (2,5-Pzdc) under solvothermal conditions. A single-crystal X-ray diffraction analysis revealed that 1 has a 3D structure and crystallizes in the triclinic P space group. In addition, the uniform crystal growth of this MOF on a conducting glass (FTO) substrate was successfully achieved using electrochemical deposition techniques. Only a handful of MOFs have been reposed to grown on conductive surfaces, which makes this study an important focal point for future research on the applications of MOF-based devices in microelectronics.     

Composition and antifungal activities of the leaf essential oil of Litsea coreana from Taiwan

The hydrodistilled leaf essential oil of Litsea coreana was analyzed by GC/FID and GC/MS. Fifty-two compounds were identified, the main components being n-decanal (27.5%), 2E,6E-farnesol (25.8%), beta-eudesmol (10.3%), ethyl n-dodecanoate (8.0%) and tau-cadinol (6.6%). Oxygenated sesquiterpenes (56.8%) and non-terpenoids (37.0%) were the predominant groups of compounds. The leaf oil exhibited excellent antifungal and anti-wood-decay fungal activities.     

Ultrasensitive detection of indoleamines by combination of nanoparticle-based extraction with capillary electrophoresis/laser-induced native fluorescence

For the first time, citrate-capped gold nanoparticles (citrate-AuNPs) have been used for the selective extraction of indoleamines – 5-hydroxytryptophan (5-HTP), tryptophan (Trp), tryptamine (TA), 5-hydroxytryptamine (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) – prior to their analysis by capillary electrophoresis/laser-induced native fluorescence (CE/LINF). The extinction spectra obtained for the citrate-AuNPs in the presence of indoleamines revealed that 5-HTP, 5-HT, and 5-HIAA were extracted mainly because of van der Waals interactions between the indole ring and the citrate-AuNPs (hydrophobic surface), while 5-HT and TA were extracted by electrostatic attractions between the amine group of the indoleamines and the citrate ligands adsorbed on the AuNP surface. The extracted indoleamines could be liberated from the AuNP surface by the addition of high concentrations of 2-mercaptoethanol (2-ME), which binds strongly to the AuNPs. The sensitivity of this method to indoleamines could be significantly enhanced by increasing the AuNP concentration, incubation time, and sample volume. Under optimal extraction and separation conditions, the combination of NP-based extraction and CE-LINF provided 48-, 4077-, 985-, 920-, and 4030-fold improvements in the limits of detection (signal-to-noise ratio of 3) for 5-HTP, Trp, TA, 5-HT, and 5-HIAA as compared to the analysis of five indoleamines by CE-LINF. In addition, this proposed method was successfully used for the determination of TA and 5-HT in urine.     

Statistical properties of agent-based models in markets with continuous double auction mechanism

Real world markets display power-law features in variables such as price fluctuations in stocks. To further understand market behavior, we have conducted a series of market experiments on our web-based prediction market platform which allows us to reconstruct transaction networks among traders. From these networks, we are able to record the degree of a trader, the size of a community of traders, the transaction time interval among traders and other variables that are of interest. The distributions of all these variables show power-law behavior. On the other hand, agent-based models have been proposed to study the properties of real financial markets. We here study the statistical properties of these agent-based models and compare them with the results from our web-based market experiments. In this work, three agent-based models are studied, namely, zero-intelligence (ZI), zero-intelligence-plus (ZIP) and Gjerstad-Dickhaut (GD). Computer simulations of variables based on these three agent-based models were carried out. We found that although being the most naive agent-based model, ZI indeed best describes the properties observed in real markets. Our study suggests that the basic ingredient to produce the observed properties from real world markets could in fact be the result of a continuously evolving dynamical system with basic features similar to the ZI model.