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991.
Polymer‐dispersed liquid crystal (PDLC) composite films were fabricated by thermal polymerization with E7 liquid crystal, monomers, and novel azobenzene derivatives synthesized in this study. To investigate the effects of azocompounds on the optical switching of PDLC films, a series of novel azobenzene derivatives of 4‐alkyloxy‐4′‐methoxyazobenzene with carbon numbers of 3–6, chiral compounds of amyl‐4‐(4‐hexyloxyphenylazo)benzoate, and bornyl‐4‐(4‐hexyloxyphenylazo)benzoate were synthesized. The compounds synthesized in this investigation were identified using FTIR, NMR, and elemental analysis. The optical texture of the composite films was analyzed under crossed nicols with a polarizing microscope. The morphological observation of the solid polymer in the composite films was performed with a scanning electron microscope (SEM). The optical behavior of the composite films on UV irradiation and the effects of the curing time on the thermal stability of the composite films were investigated. Isomerization of the azobenzene derivatives due to UV irradiation was confirmed by a texture study and image recording method. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 789–799, 2004 相似文献
992.
Hsin-Ling Yin Chun-Chieh Wu Chih-Hung Lin Chee-Yin Chai Ming-Feng Hou Shu-Jyuan Chang Hung-Pei Tsai Wen-Chun Hung Mei-Ren Pan Chi-Wen Luo 《International journal of molecular sciences》2016,17(9)
Triple negative breast cancer (TNBC) displays higher risk of recurrence and distant metastasis. Due to absence of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2), TNBC lacks clinically established targeted therapies. Therefore, understanding of the mechanism underlying the aggressive behaviors of TNBC is required for the design of individualized strategies and the elongation of overall survival duration. Here, we supported a positive correlation between β1 integrin and malignant behaviors such as cell migration, invasion, and drug resistance. We found that silencing of β1 integrin inhibited cell migration, invasion, and increased the sensitivity to anti-cancer drug. In contrast, activation of β1 integrin increased cell migration, invasion, and decreased the sensitivity to anti-cancer drug. Furthermore, we found that silencing of β1 integrin abolished Focal adhesion kinese (FAK) mediated cell survival. Overexpression of FAK could restore cisplatin-induced apoptosis in β1 integrin-depleted cells. Consistent to in vitro data, β1 integrin expression was also positively correlated with FAK (p = 0.031) in clinical tissue. More importantly, β1 integrin expression was significantly correlated with patient outcome. In summary, our study indicated that β1 integrin could regulate TNBC cells migration, invasion, drug sensitivity, and be a potential prognostic biomarker in TNBC patient survival. 相似文献
993.
Hung‐Te Chang Hsun‐Tsing Lee En‐Chiuan Chang Mou‐Yung Yeh 《Polymer Engineering and Science》2007,47(9):1380-1387
Two soluble fluorescent polymers, poly(2‐decyloxy‐5‐(4′‐tert‐butylphenyl)‐1,4‐phenylenevinylene) (DtBP‐PPV) and poly(2‐decyloxy‐1,4‐phenylenevinylene) (DO‐PPV), were prepared by a method similar to the Gilch procedure. The DtBP‐PPV and DO‐PPV have a same chemical structure except for the conjugated tert‐bytulphenyl substituents in the former. The polymers are characterized by using 1H NMR, FTIR, UV–vis, photoluminescence (PL), and electroluminescence (EL) spectroscopies and thermogravimetric analysis (TGA). The 1H NMR spectra show no tolane‐bis‐benzyl (TBB) structure defects in DtBP‐PPV but some in DO‐PPV. Both UV–vis absorption and PL emission peaks of the DtBP‐PPV exhibit a red‐shift phenomenon as compared with those of the DO‐PPV. Moreover, with the DtBP‐PPV and DO‐PPV acting as light‐emitting polymers separately, EL devices were fabricated with a sequential lamination of ITO/PEDOT/DtBP‐PPV (or DO‐PPV)/Ca/Ag. The DtBP‐PPV‐based device shows a lower turn‐on voltage, a longer EL emission wavelength, and a higher brightness than the DO‐PPV‐based device. The maximum brightness of DtBP‐PPV‐based device is 57 cd/m2 at an applied voltage of 12 V. POLYM. ENG. SCI., 47:1380–1387, 2007. © 2007 Society of Plastics Engineers 相似文献
994.
995.
The artificial neural network (ANN) theory has been widely applied to practical applications in hydrology. Since watershed
rainfall–runoff processes are nonlinear and exhibit spatial and temporal variability, the ANN model, which considers watershed
nonlinear characteristics, can usually but not always obtain satisfactory simulation results. The training of an ANN network
is based completely on the reliability of the available hydrologic records. The objective of this study was to provide deterministic
insight into the limitations of storm runoff simulation when using ANN. Hydrologic records of 42 storm events from two watersheds
in Taiwan were adopted for analysis. A deterministic runoff model was used to classify the hydrologic records into “usual”
and “unusual” storm events. The analytical results show that the ANN model could provide good simulation results for “usual”
storm events; however, its performance was poor when it was applied to “unusual” storm events because no consistent hydrologic
characteristics could be extracted from the storm event records using ANN. The success of the ANN model in usual storm discharge
simulations may be mainly due to the input vectors including the previous observed discharge. Moreover, the number of past
periods of rainfall that were set as the input vectors of the ANN model was found to be highly correlated with the watershed
time of concentration. It can be used to efficiently determine the ANN network structure instead of using iterative network
training. 相似文献
996.
Khanitta Somtrakoon Sudarat Suanjit Prayad Pokethitiyook Maleeya Kruatrachue Michael B. Cassidy Jack T. Trevors Hung Lee Suchart Upatham 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(11):1660-1668
BACKGROUND: Many polycyclic aromatic hydrocarbon (PAH) contaminated sites also contain high levels of toxic heavy metals. The presence of heavy metals can adversely affect PAH biodegradation. Encapsulation of bacterial cells has been shown to improve survival and activity of cells under various environmental stresses. This study examined if encapsulation of a phenanthrene‐mineralizing bacterial strain could improve its survival and phenanthrene degradation in heavy metal contaminated soils. RESULTS: Alginate encapsulation did not improve survival and phenanthrene degradation by Pseudomonas sp. UG14Lr in heavy metal contaminated soil. Phenanthrene degradation by, and survival of, free cells and alginate‐encapsulated cells were similar in soil contaminated with 5 mg kg?1 dry soil of As, Cd, or Pb. The number of UG14Lr cells decreased to undetectable level when the concentration of each heavy metal was increased to 100 mg kg?1 dry soil. UG14Lr, when inoculated as free cells, survived the best and they were detected over 60 days of incubation in soil. Cells in both wet and dry alginate beads survived less well than free cells at the higher metal concentrations. Correspondingly, phenanthrene degradation in soil inoculated with free UG14Lr was better than that in soil inoculated with alginate‐encapsulated cells. CONCLUSION: Alginate encapsulation adversely affected the survival and phenanthrene degradation ability of UG14Lr cells in heavy metal contaminated soil. It is postulated that alginate may have concentrated the metals which in turn increased the toxicity to UG14Lr cells. The results are of interest to those interested in the use of encapsulation technology to formulate microbial cells for bioremediation purposes. Copyright © 2009 Society of Chemical Industry 相似文献
997.
Shiang Suo Huang Yi Hung Chen Long Y. Chiang Ming Cheng Tsai 《Fullerenes, Nanotubes and Carbon Nanostructures》1999,7(4):551-571
The effects of hexasulfobutylated C60 (FC4S) on membrane potentials and currents were studied by tight-seal, whole-cell recording in thin slices of the neonatal rat thalamus. Silent neuron with resting membrane potentials of around -62.4 ± 0.7 mV was found in whole-cell current clamp recordings. Hexasulfobutylated C60 depolarized the neuron by a concentration dependent manner. It also (1) prolonged the decay time constant of action potential and (2) decreased the threshold of the directly elicited action potentials of the neuron. Hexasulfobutylated C60 did not alter the input resistance of the excitable membrane. In whole-cell voltage clamp studies, depolarizing command pulses from a holding potential of about -70 mV evoked a fast inward current followed by an outward current in the thalamic neurons. Hexasulfobutylated C60 (30 - 100 μM) increased the total inward sodium current of the neuron, while hexasulfobutylated C60 did not alter the outward potassium currents in all voltage steps tested. It was concluded that hexasulfobutylated C60 (1) decreased the threshold of the action potential and (2) prolonged the decay time constant of the directly elicited action potential of the neonatal rat thalamic neurons. The effect may be closely associated with the Na+ current in thalamic neurons. 相似文献
998.
999.
1000.
William O. S. Doherty Christopher M. Fellows Sargon Gorjian Ernest Senogles Wai Hung Cheung 《应用聚合物科学杂志》2003,90(1):316-325
Rapid flocculation and sedimentation of suspended particles in primary cane sugar juice is achieved using a high molecular weight anionic polymer flocculant. This work reports on efforts to enhance the performance of an anionic flocculant by the addition of cationic polymers. Homopolymers of poly(trimethylammonium ethyl methacrylate chloride) (TMAEMAC) and cationic copolymers of poly(trimethylammonium ethyl acrylate chloride) (TMAEAC) and acrylamide were synthesized and their performance, to enhance the flocculation and sedimentation of cane sugar juice particles, was evaluated by turbidity and settling rate measurements. The charge–patch mechanism best explains the performance of the homopolymers, whereas the action of the copolymers is attributed to the bridging mechanism. The results of this work indicate that the copolymers are more effective than the homopolymers to aid flocculation and sedimentation of the cane sugar juice particles, and that the best‐performing polymers are those that act by the bridging mechanism. Addition of increased amounts of anionic flocculant did not confer an improvement, suggesting that the cationic bridging flocculant targets a different population of particles that is largely responsible for the residual turbidity. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 316–325, 2003 相似文献