95,027 research outputs found
Interview with Theodore Y. Wu
No full textAn interview in three sessions, February-March 2002, with Theodore Y. Wu, professor of engineering science, emeritus, in the Division of Engineering and Applied Science. Dr. Wu was born in China and received his BSc from Chiao-Tung University (1946), his MS from Iowa State University (1948), and his PhD from Caltech (1952).
In this interview, he recalls his boyhood and tribulations during Japan's invasion of China in World War II, his emigration and matriculation at Iowa State in 1948, and his arrival at Caltech a year later. Recollections of H. S. Tsien, R. A. Millikan, Theodore von Kármán, Julian Cole. Works with Paco Lagerstrom's aeronautics group developing asymptotic perturbation method pioneered by Ludwig Prandtl. Joins faculty as a research fellow in 1952. Interest in hydrodynamics. Origins of the department of engineering science in the mid-1950s by Tsien, Milton Plesset, and Charles De Prima.
Interest in bioengineering, beginning in 1960; studies bird flight and fish locomotion. Discusses influence of G. I. Taylor and James Lighthill, and recalls his own work on flagellar and ciliary motion of microorganisms. Caltech's 1974 pioneering symposium on Swimming and Flying in Nature; new field of biofluiddynamics. Recollections of Y. C. (Burt) Fung.
Recalls his sabbatical, 1964-65, at University of Hamburg with Georg Weinblum. Joins Advisory Committee for Reactor Safeguards. Recollections of Caltech presidents Lee DuBridge and Marvin L. Goldberger. Visit to China in 1979.
Discusses his work, since 1996 retirement, on modeling of water waves; solitons and tsunamis. Concludes with comments on good relations between Chinese and Chinese American scientists and the flood of Chinese students to US for graduate work in late 1970s, after reestablishment of diplomatic relations
Phospholipid meets all-Trans-retinal: The making of RPE bisretinoids
No full textThe lipid phase of the photoreceptor outer segment membrane is essential to the photon capturing and signaling functions of rhodopsin. Rearrangement of phospholipids in the bilayer accompanies the formation of the active intermediates of rhodopsin following photon absorption. Furthermore, evidence for the formation of a condensation product between the photolyzed chromophore all-trans-retinal and phosphatidylethanolamine indicates that phospholipid may also participate in the movement of the retinoid in the membrane. The downside of these interactions is the formation of bisretinoid-phosphatidylethanolamine compounds that accumulate in retinal pigment epithelial cells with age and that are particularly abundant in some retinal disorders. The propensity of these compounds to negatively impact on the cells has been linked to the pathogenesis of some retinal disorders including juvenile onset recessive Stargardt disease and age-related macular degeneration.-Sparrow, J. R., Y. Wu, C. Y. Kim, and J. Zhou. Phospholipid meets all-trans-retinal: the making of RPE bisretinoids. Copyright �� 2010 by the American Society for Biochemistry and Molecular Biology, Inc
Chao Yuen Ren (1892–1982)
No full textY. R. Chao is easily the most famous linguist to have come out of China. Born before the end of the last dynasty in China, he received a traditional Confucian education, but was also one of the first Chinese people to be sent to the West for training in modern Western science (under the Boxer Indemnity Fund). The remarkable breadth and scope of his studies included physics, mathematics, linguistics, musical and literary composition, and translation, and he was a pioneer in many of these fields
Control and Filtering for Discrete Linear Repetitive Processes with H infty and ell 2--ell infty Performance
No full textRepetitive processes are characterized by a series of sweeps, termed passes, through a set of dynamics defined over a finite duration known as the pass length. On each pass an output, termed the pass profile, is produced which acts as a forcing function on, and hence contributes to, the dynamics of the next pass profile. This can lead to oscillations which increase in amplitude in the pass to pass direction and cannot be controlled by standard control laws. Here we give new results on the design of physically based control laws for the sub-class of so-called discrete linear repetitive processes which arise in applications areas such as iterative learning control. The main contribution is to show how control law design can be undertaken within the framework of a general robust filtering problem with guaranteed levels of performance. In particular, we develop algorithms for the design of an H? and dynamic output feedback controller and filter which guarantees that the resulting controlled (filtering error) process, respectively, is stable along the pass and has prescribed disturbance attenuation performance as measured by and – norms
SPECIFIC RECOGNITION OF N-ACETYLNEURAMINIC ACID IN THE G(M2) EPITOPE BY HUMAN G(M2) ACTIVATOR PROTEIN
No full textG(M2) Activator is a low molecular weight protein cofactor that stimulates the enzymatic conversion of G(M2) into G(M3) by human beta-hexosaminidase A and also the conversion of G(M2) into G(A2) by clostridial sialidase (Wu, Y.-Y., Lockyer, J. M., Sugiyama, E., Pavlova, N. V., Li, Y.-T., and Li, S.- C. (1994) J. Biol. Chem. 269, 16276-16283). Among the five known activator proteins for the enzymatic hydrolysis of glycosphingolipids, only G(M2) activator is effective in stimulating the hydrolysis of G(M2). However, the mechanism of action of G(M2) activator is still not well understood, Using a unique disialosylganglioside, GalNAc-G(D1a), as the substrate, we were able to show that in the presence of G(M2) activator, GalNAc-G(D1a) was specifically converted into GalNAc-G(M1a) by clostridial sialidase, while in the presence of saposin B, a nonspecific activator protein, GalNAc-G(D1a) was converted into both GalNAc-G(M1a) and GalNAc-G(M1b). individual products generated from GalNAc-G(D1a) by clostridial sialidase were identified by thin layer chromatography, negative secondary ion mass spectrometry, and immunostaining with a monoclonal IgM that recognizes the G(M2) epitope. Our results clearly show that G(M2) activator recognizes the G(M2) epitope in GalNAc-G(D1a). Thus, G(M2) activator may interact with the trisaccharide structure of the G(M2) epitope and render the GalNAc and NeuAc residues accessible to beta-hexosaminidase A and sialidase, respectively
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
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