Micro/Nano imprinting or hot embossing is currently a target of interest for industrial production of micro and Nano devices for the low cost aspect. In Fluidic MEMS (Micro Electromechanical Systems) applications, polymer materials have been widely employed for their low cost to fabricate the economical products (Becker and Heim in Sens Acuators A 83: 120-135, 2000; Becker and Gaertner in Mol Biotechnol 82:89-99, 2001). However glasses are much more suitable for the higher temperature applications or under the stronger chemical environments. Moreover UV absorption of glass materials is much less than that of polymers, which is the advantage for bio-analysis. In Optical MEMS as well, glasses are good candidate materials for the better optical properties, such as high refractive index, low UV absorption and others. Although wet etching of glasses is widely employed for fabrication of fluidic MEMS devices, the wet etching is not satisfactory for the low machining resolution, the isotropic etched profile and poor roughness of the fabricated structures. Dry etching of glasses is then an alternative for Micro/Nano structuring, but the etching rate is extremely low (order of 0.1 lm/min) and the cost is too high because of the expensive RIE (Reactive Ion Etching) facility. Above mentioned is the reason why we are interested in hot embossing or imprinting of glasses of Micro/Nano scale. In our previous study, Micro/Nano imprinting was developed for Pyrex glasses using GC (Glassy Carbon) mold prepared by FIB machining (Takahashi et al. in Symposium on DTIP 2004 pp 441-446, 2004. The disadvantage of FIB machining is limited area of etching. The typical area of FIB is less than several hundreds micrometer square. This is the reason why we tried the large area of embossing using GC mold fabricated by dicing machine. Micro hot embossed test structures were successfully demonstrated with good fidelity. Fabricated micro structures can be applied for fabrication of microchamber array for PCR (Akagi et al. in Sci Techol
A 23-year-old asymptomatic woman was referred to our hospital for further examination of a systolic ejection murmur with fixed splitting of the second heart sound auscultated at the third left sternal border. Initial echocardiography could not detect the cause. Subsequently performed low-dose computed tomography, however, ruled out the possibility of any congenital heart diseases, but revealed a markedly shortened anteroposterior diameter of the chest, which led us to a diagnosis of straight back syndrome. A vertically oriented “pancake” appearance of the heart, straight vertebral column, and compression of the right ventricular outflow tract were clearly demonstrated on the reconstructed images.
Uric acid (UA) is a final product of catabolization of the purine nucleosides, and it causes problems because humans do not possess the enzyme to digest it to a soluble form. On the other hand, as a substitute antioxidant, it may play a protection role, because it is involved in many pathological changes and/or damage development. Most UAs are excreted by urine, and the determination of UA in human urine and serum is very important due to the need for data in the diagnosis and therapy of patients suffering from a range of disorders, such as gout, hyperuricemia, malignant lymphoma, hemolytic anemia, diabetes, renal insufficiency, and Lesch-Nyhan syndrome. 1 In addition, hyperuricemia has recently become a useful index of metabolic syndrome. 2Methods for analyzing UA include spectrophotometry, 3-7 electroanalysis, [8][9][10][11][12] high performance liquid chromatogtaphy (HPLC), 13 fluorometry, [14][15][16] and chemiluminescence method. [17][18][19] While there are many colorimetric assays 20,21 for the determination of UA, most of them are not satisfactory, showing low sensitivity, low reproducibility, time-consuming procedure and interference of foreign substances such as ascorbic acid.On the other hand, UA has several donor atoms capable of metal complex formation and binding with copper(II), zinc(II), nickel(II), iron(II), and similar metals. In analysis of a compound having complex-forming ability, we have recognized that a method with a dye and a metal ion was a very superior procedure with simplicity, sensitivity and selectivity, and we have developed simple and sensitive methods for various organic compounds, such as hydrogen peroxide, 22 ethylenediaminetetraacetic acid, 23 propranolol 24 and biological active thiols. 25In the color reaction between o-hydroxyhydroquinonephthalein (QP) and palladium(II) in a hexadecyltrimethylammonium (HTA) surfactant medium, we noticed that the color development of the QP-palladium(II)-HTA complex was interfered with severely by small amounts of UA, and the decrease in absorbance of QP-palladium(II)-HTA was proportional to the concentration of UA. Here, a new, sensitive, and simple spectrophotometric determination of UA is described, and the proposed method is applied to the assay of UA in human urine. Experimental Reagents and apparatusA stock solution (1.0 × 10 -2 M, 1 M = 1 mol dm -3 ) of UA was prepared by dissolving the UA (Wako Pure Chem. Co. Ltd.) in small amounts of 0.1 M sodium hydroxide solution and diluting with water. The working solution was prepared by suitable dilution of this stock solution as required. A solution (5.0 × 10 -4 M) of palladium(II) was prepared from a stock solution (Wako Pure Chem. Co. Ltd., 1000 μg dm -3 ) by dilution with water. A solution of QP, which had been synthesized according to a method described in the literature, 26,27 was prepared in a 1.0 × 10 -3 M methanol solution containing one drop of hydrochloric acid. A 1.0 × 10 -2 M aqueous solution of hexadecyltrimethylammonium bromide (HTAB, Tokyo Kasei Kogyo Co.) was prepared by disso...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.