Studying cellular crosstalk is important for understanding tumor initiation, progression, metastasis, and therapeutic resistance. Moreover, a three-dimensional (3D) cell culture model can provide a more physiologically meaningful culture microenvironment. However, studying cellular crosstalk in a 3D cell culture model involves tedious processing. In this study, a paper/poly(methyl methacrylate) (PMMA) hybrid 3D cell culture microfluidic platform was successfully developed for the study of cellular crosstalk. The platform was a paper substrate with culture microreactors placed on a PMMA substrate with hydrogel-infused channels. Different types of cells were directly seeded and cultured in the microreactors. Aberrant cell proliferation of the affected cells was induced by secretions from transfected cells, and the proliferation ratios were investigated using a colorimetric method. The results showed that the responses of cellular crosstalk were different in different types of cells. Moreover, neutralizing and competitive assays were performed to show the functionality of the platform. Additionally, the triggered signaling pathways of the affected cells were directly analyzed by a subsequent immunoassay. The microfluidic platform provides a simple method for studying cellular crosstalk and the corresponding signaling pathways in a 3D culture model.
The vibrational structure of the S(1)-S(0) electronic band of phenylacetylene has been recorded by 1 + 1 resonance-enhanced multiphoton ionization, accompanied by slow electron velocity map imaging photoelectron spectroscopy at each resonant vibrational band. Assignments of the S(1) vibrations (up to 2000 cm(-1) above the band origin) are based upon the relative intensities of the vibronic bands calculated by complete second-order vibronic coupling, vibration-rotation (Coriolis and Birss) coupling calculations, and the vibrational structure of the S(1) resonant photoelectron spectra. Although this is an allowed electronic transition, the relative intensities of the a(1) bands are often largely determined by vibronic coupling rather than simple Franck-Condon factors, and second-order coupling is substantial. Nonsymmetric vibrations have intensities obtained through either vibronic or Coriolis coupling, and the calculations have been instrumental in discriminating between alternate possibilities in the assignments. Strong vibronic effects are expected to be present in the spectra of most monosubstituted benzenes, and the calculations presented here show that theoretical treatments based upon electronic structure calculations will generally be useful in the analysis of their spectra.
Owing to growing demand for figure hugging and comfortable clothes made with stretchable fibers, spandex fibers are being used in underwear, diapers, hosiery, leisurewear, sportswear, jeans, and so on. In the present study a polyester core-spun yarn containing spandex fibers was made using a self-designed, multi-section drawing frame and a ring spinning frame. The mechanical properties of the core-spun elastic yarns were examined in various processing conditions. The analytical results show that when the main drawing ratio of the spandex fibers was either 2.2 or 2.7, the maximum breaking tenacity and elongation of the core-spun elastic yarns exceeded those in any other of the main drawing ratio conditions. Demand for elastic fibers is still growing. Consumption of elastic fibers reached 137,000 tons in Asia in 2001. Bayer in Germany was the first to develop polyurethane elastic fibers. US scientists began to develop the commercial applications of polyurethane from the 1940s. Soft and flexible elastomer or hard and abrasion-resistant materials can be fabricated with polyurethane. Spandex fibers are long-chain polymer fibers containing at least 85% segmented polyurethane [2]. Spandex fibers have been developed and produced by numerous companies, for example Spanzelle, Vyrene, Lycra, Glospan, etc.Various previous studies have reported the physical and chemical properties of spandex fibers. An elastic fiber has been characterized by high breaking elongation (exceeding 100% and generally 500 to 800%), a low modulus of elasticity (approximately 1/1000 that of a conventional "hard" fiber, such as nylon, cotton, and so on), and both a high degree and a high rate of recovery from 100% stretching (about 95%). Spandex fibers are resistant to hydrolysis (Lycra had power retention of 100% after boiling for 1 hour in water at pH 3 to 11). In addition the spandex fibers have good resistance to ultraviolet radiation, oxygen, heat, and oil [5]. Babaarslan described a method of producing a polyester/viscose core-spun yarn using spandex fibers. The spandex fibers (Lycra) were covered with polyester staple fibers of 38 mm and 1.3 dtex and viscose staple fibers of 38 mm and 2.4 dtex using a modified ring spinning frame with a positive feed roller system and a V-groove guide. The mechanical properties of the yarn and its uniformity were examined. The corespun yarns had lower tenacity than polyester/viscose staple yarns, but they had higher elongation [1]. Previously, several investigators have studied core-yarns containing a nylon or polyester filament [3,4,6,7].Nowadays, the textile industry is producing various core-spun yarns with spandex fibers of 22 to 156 dtex. The spandex fibers covered with staple fibers can be used for daily commodities and industrial products. This work made a polyester core-spun yarn from spandex fibers using a self-designed, multi-section drawing frame and a ring spinning frame. To keep their elas-
The sensitivity of vibronic calculations to electronic structure methods and basis sets is explored and compared to accurate relative intensities of the vibrational bands of phenylacetylene in the S(1)(A(1)B(2)) ← S(0)(X(1)A(1)) transition. To provide a better measure of vibrational band intensities, the spectrum was recorded by cavity ringdown absorption spectroscopy up to energies of 2000 cm(-1) above the band origin in a slit jet sample. The sample rotational temperature was estimated to be about 30 K, but the vibrational temperature was higher, permitting the assignment of many vibrational hot bands. The vibronic structure of the electronic transition was simulated using a combination of time-dependent density functional theory (TD-DFT) electronic structure codes, Franck-Condon integral calculations, and a second-order vibronic model developed previously [Johnson, P. M.; Xu, H. F.; Sears, T. J. J. Chem. Phys. 2006, 125, 164331]. The density functional theory (DFT) functionals B3LYP, CAM-B3LYP, and LC-BLYP were explored. The long-range-corrected functionals, CAM-B3LYP and LC-BLYP, produced better values for the equilibrium geometry transition moment, but overemphasized the vibronic coupling for some normal modes, while B3LYP provided better-balanced vibronic coupling but a poor equilibrium transition moment. Enlarging the basis set made very little difference. The cavity ringdown measurements show that earlier intensities derived from resonance-enhanced multiphoton ionization (REMPI) spectra have relative intensity errors.
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