Antilipolytic actions of insulin on basal and hormone-induced lipolysis in rat adipocytes

The levels of insulin, free fatty acids (FFA), and triglycerides in rat sera increase with age. The increase in serum FFA levels accompanied the stimulation of basal lipolysis (i.e., lipolysis in the absence of lipolytic agents) in fat cells and enlargement of the diameter of the cells. An overnight fast resulted in a significant increase in basal lipolysis in fat cells from 6- and 8-week-old rats. Although insulin inhibited lipolysis induced by norepinephrine and ACTH at a concentration of 10(-10) M, it failed to inhibit basal lipolysis even at a concentration of 10(-6) M. Propranolol, another antilipolytic agent like insulin, also did not affect basal lipolysis. Insulin did not inhibit the accelerated basal lipolysis in enlarged fat cells, fasted fat cells, and sonicated cells. These results indicate that insulin inhibits only the lipolysis induced by lipolytic agents such as norepinephrine and ACTH but not the basal lipolysis found in the absence of lipolytic agents. The possibility that free fatty acids produced by enlarged fat cells initiate insulin resistance and diabetes mellitus, is discussed.     

Optical rotatory dispersion and circular dichroism studies of copolyaspartates with long alkyl side chain

Copoly(hexyl-l-aspartate-benzyl-l-aspartate), copoly(nonyl-l-aspartate-benzyl-l-aspartate) and copoly(dodecyl-l-aspartate-benzyl-l-aspartate) with various compositions were prepared by ester exchange reaction of poly(β-benzyl-l-aspartate). Copolyaspartates of low degree of alkylation were found to take a left handed α helix, similar to poly(β-benzyl-l-aspartate), and those of high degree of alkylation changed to a right handed α helix. Copoly(hexyl-l-aspartate-benzyl-l-aspartate) and copoly(dodecyl-l-aspartate-benzyl-l-aspartate) changed helix sense from left to right at 50% hexylation and 10% dodecylation, respectively. A small induced circular dichroism trough appeared around 230nm for these two copolyaspartates above 75% alkylation, indicative of a certain ordering of the carbonyl group due to the formation of an ordered structure of a long alkyl side chain. However, copoly(nonyl-l-aspartate-benzyl-l-aspartate) of 13% nonylation exhibited the induced circular dichroism spectrum and took a left handed α helix. Copoly(nonyl-l-aspartate-benzyl-l-aspartate) caused the reversal in helix sense above 70% nonylation according to a stabilizing effect of the ordered structure of the side chain.     

Sorption and permeation behavior of water vapor and carbon dioxide gas through ethylene ionomer membranes

Sorption and permeation of water vapor and carbon dioxide gas through ethylene ionomer membranes were studied as a function of pressure. Water sorption increased with an increase of the acid content and especially degree of neutralization of ethylene ionomers. The sodium salt ionomer enhanced water sorption compared to the zinc salt ionomer. However, there was no remarkable difference of permeability coefficient of water vapor through the sodium and zinc ionomer membranes. Diffusion coefficient of the sodium salt ionomer is one order smaller than that of zinc salt ionomer, corresponding to an immobilized water structure in the sodium salt ionomer. Differential scanning calorimetry studies on water sorbed to membrane manifested that water sorbed was almost nonfreezable. Sorption of carbon dioxide gas in ethylene ionomers was a dual-mode type. The pressure dependence of permeability coefficient of carbon dioxide gas was interpreted in terms of a partial immobilization model, independent of the kind of the metal salt in ethylene ionomer.     

Novel at-design-rule via-to-metal overlay metrology for 193-nm lithography

The effect of scanner aberrations on pattern placement errors (PPE) in the copper interconnect lithography process is studied both in simulations and experimentally. A new grating-based overlay mark, advanced imaging metrology, enables measuring device feature overlay. It is shown that the grating mark exhibits superior performance over conventional box-in-box marks. A comparison between grating-based optical and direct CD scanning electron microscopic (SEM) device overlay measurements was done. Both CD SEM and grating mark optical measurements show sensitivity to PPE. Good matching between the new grating target and device overlays was demonstrated.     

Influence of side chain structure on sorption of xenon and carbon dioxide gas by polypeptide membranes

The influence of side chain structure on sorption of xenon and carbon dioxide gas by polypeptides is examined in two ways: chemical structure of side chain and higher order structure of the side chain region. Sorption of xenon gas increases progressively with increase in side chain length of poly(n-alkyl L -glutamates). The sorption isotherms of a polymer at various temperatures are reduced to one curve when the data are arranged in the form of sorption per residue versus fugacity ratio (as activity). The sorption of carbon dioxide gas shows a minimum at an intermediate length of side chains, corresponding to poly(n-propyl or n-butyl glutamate). The behavior is considered the result of overlapping influences of looseness of the side chain region and density of polar groups. The Langmuir constants and the enthalpy and entropy of sorption explain this quantitatively. Sorption of carbon dioxide gas is influenced by the higher-order structure of poly(γ-benzyl L -glutamate). In this polymer, the benzyl ester part is the main sorption site, and it was confirmed that the stacking between side-chain benzene rings significantly reduces the extent of sorption.     

Numerical analysis of flow in ultra micro centrifugal compressor -influence of meridional configuration

A single stage ultra micro centrifugal compressor constituting ultra micro gas turbine is required to operate at high rotational speed in order to achieve the pressure ratio which establishes the gas turbine cycle. As a consequence, the aerodynamic losses can be increased by the interaction of a shock wave with the boundary layer on the blade surface. Moreover, the centrifugal force which exceeds the allowable stress of the impeller material can act on the root of blades. On the other hand, the restrictions of processing technology for the downsizing of impeller not only relatively enlarge the size of tip clearance but also make it difficult to shape the impeller with the three-dimensional blade. Therefore, it is important to establish the design technology for the impeller with the two-dimensional blade which possesses the sufficient aerodynamic performance and enough strength to bear the centrifugal force caused by the high rotational speed. In this study, the flow in two types of impeller with the two-dimensional blade which have different meridional configuration was analyzed numerically. The computed results clarified the influence of the meridional configuration on the loss generations in the impeller passage.     

Theoretical study of van der Waals dispersion pressures considering one-dimensional material distributions in the in-plane direction

The van der Waals dispersion pressures between a half-space consisting of a uniform material and a half-space with a one-dimensional material distribution in the in-plane direction have been theoretically derived. Two patterns of material distribution were considered: a periodic distribution of materials (Pattern 1) and a distribution of two materials with a single interface (Pattern 2). The van der Waals pressure for Pattern 1 was derived based on a Fourier series, while the van der Waals pressure for Pattern 2 was derived as elementary functions. Both of the van der Waals pressures derived consist of two terms: a conventional term between half-spaces made of uniform materials and a spatial fluctuation term due to the material distribution. The basic characteristics of these van der Waals pressures were quantitatively clarified. Furthermore, an approximate method for obtaining the van der Waals pressure of Pattern 1 from Pattern 2 was proposed.     

Structure and gas sorption properties of an aromatic polyamide with long alkyl side chains

An aromatic polyamide with long alkyl side chain, A‐C12, was synthesized from the condensation of 1,4‐didodecylester of pyromellitic acid and p‐phenylenediamine to clarify the relationship between its higher order structure and gas sorption properties. A‐C12 formed a layered structure composed of alternating rigid aromatic main chain layers and flexible dodecyl side chain layers. This polyamide could be imidized by the usual imidization method. Imidized A‐C12 could not keep the layered structure of A‐C12. CO₂ sorption of A‐C12 occurred only in the side chain layer region, which is almost a liquid‐like environment, and the sorption isotherms obeyed Henry's law. This result also indicates that the main chain layer is very dense and cannot sorb CO₂. On the other hand, imidized A‐C12 showed a large sorption amount of CO₂ and dual mode sorption, despite high density, meaning imidized A‐C12 does not contain a layered order structure but an amorphous glassy state. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1771–1775, 2005