Contents and its change during storage of alpha-solanine and alpha-chaconine in potatoes

Contents of alpha-solanine and alpha-chaconine in native species of potato (May Queen, Danshaku and Waseshiro), and in species (Jagakids Red '90 (Red) and Jagakids Purple '90 (Purple)) on the market, and their change during storage at room temparature were investigated. alpha-Solanine and alpha-chaconine were extracted from potatoes with methanol, cleaned up by using a Sep-Pak Plus C18 cartridge, and then subjected to HPLC. The recoveries of alpha-solanine and alpha-chaconine from potatoes were both more than 96%, and the quantitation limits were both 2 microg/g. alpha-Solanine and alpha-chaconine were detected in periderm in all samples at the levels of 260-320 microg/g in May Queen,190-240 microg/g in Danshaku, 43-63 microg/g in Waseshiro, 140-200 microg/g in Red and 84-130 microg/g in Purple, respectively. alpha-Solanine and alpha-chaconine were detected in the cortex in all samples of May Queen and Danshaku at the levels of 2.7-12 microg/g and 5.8-31 microg/g, respectively. Contents of alpha-solanine and alpha-chaconine in the cortex of May Queen and Danshaku were less than 10% of those in the periderm. When potatoes were stored for 90 days at room temparature in a dark place, no marked change in the contents of alpha-solanine and alpha-chaconine was observed in any of the potato samples.     

Adaptor polymerase chain reaction for single molecule amplification

The adaptor polymerase chain reaction (PCR) permits the amplification of DNA fragments with arbitrary sequences. In this paper, we describe the successful amplification of plasmid-derived single molecule DNAs digested by a restriction enzyme. By using adaptors made of short and long oligonucleotides, nonspecific interactions during PCR were suppressed. The method will be applicable to the detection of single molecule DNA fragments even if their sequence is unknown.     

Anion exchange membranes prepared from chloromethylstyrene and 2-methyl-5-vinylpyridine

Strongly basic anion exchange membranes were prepared by the radical copolymerization of chloromethylstyrene and 2-methyl-5-vinylpyridine. The formation of a three-dimensional structure and the presence of the quarternary pyridinium group were confirmed by infrared spectrum analysis and its strongly basic anion exchange properties. Their electrochemical properties and morphology were compared with those of the anion exchange membranes prepared from chloromethylstyrene-divinylbenzene and 2-methyl-5-vinylpyridine-divinylbenzene. The chloromethylstyrene-2-methyl-5-vinylpyridine membranes were proved to have larger anion exchange capacity, smaller electric resistance, larger water content, and higher permeability than the chloromethylstyrene-divinylbenzene and 2-methyl-5-vinylpyridine-divinylbenzene membranes. Also, the membranes have heterogeneity in the cross-linking structure.     

Stimulated activation of platelet-derived growth factor receptor in vivo in balloon-injured arteries: a link between angiotensin II and intimal thickening

BACKGROUND: Growth factors such as platelet-derived growth factor (PDGF) have been postulated to be important mediators of neointimal formation in balloon-injured artery. Binding of growth factors to their receptors activates intrinsic receptor tyrosine kinase, resulting in tyrosine phosphorylation of receptors themselves and cellular substrate proteins. We investigated in vivo activities of growth factors by determining the extent of tyrosine phosphorylation of growth factor receptors and substrate proteins in injured artery. METHODS AND RESULTS: Rat balloon-injured carotid artery was analyzed for phosphotyrosine content of PDGF alpha- and beta-receptors, epidermal growth factor (EGF) receptors, and insulin receptor substrate-1 (IRS-1) by immunoprecipitation and anti-phosphotyrosine Western blot. The development of intimal thickening after deendothelializing balloon catheterization of rat carotid artery was accompanied by transient twofold to threefold increases in the extent of tyrosyl phosphorylation of PDGF alpha- and beta-receptors but not EGF receptor or IRS-1. The AT1 angiotensin II (Ang II) receptor antagonist TCV-116 markedly inhibited both tyrosyl phosphorylation of PDGF alpha- and beta-receptors and intimal thickening. The AT1 antagonist reduced mRNA levels of both PDGF-A and -B chains in injured arteries. CONCLUSIONS: The present study provides direct evidence for increased PDGF activities in injured artery in situ and the involvement of Ang II in stimulated activation of PDGF receptors. These results are consistent with the pathogenetic role for PDGF in intimal thickening.     

Make-or-buy decisions in R&D: small technology based firms inthe United States and Japan

This paper examines key factors which affect make-or-buy decisions in research and development (R&D) settings-whether technology is developed in house or acquired from external sources (e.g., through licensing or R&D contracts). The paper constructs several hypotheses from the literature survey and discussions and tests these hypotheses by using data from small technology based firms in the United States and Japan. Our analyses show external technology acquisitions are more likely to be practiced when the number of rivals expected to develop a similar product is greater, and the needed technology is less related to a firm's core technology. Our analyses also imply two qualitatively different goals in external technology acquisitions: to shorten development time, and thereby reap short-term profits (short-term strategy), and to maximize long-term profits over the life of the innovation (long-term strategy). Our analyses suggest the dominance of the former strategy     

Design of stabilized digital inverse systems

As is well known, due to the existence of unstable limiting zeros and/or the minimum phase property of continuous-time systems, there are many cases that the discretized systems are of non-minimum phase. In this case, it is impossible to construct a stable digital inverse by usual methods. However, in this paper, we will show that if the inter-sample output is used in the design, one can always construct a stable digital inverse system.     

Soliton self-frequency shift accelerated by femtosecond soliton interaction

Nonlinear interaction between femtosecond solitons has been investigated in a distributed erbium-doped fibre amplifier (DEDFA). It is shown that when the input femtosecond soliton pair is in phase, the soliton self-frequency shift is greatly accelerated by soliton interaction.<>     

All-optical bit-pattern matching with photonic switching arrays

An all-optical XOR logic circuit is demonstrated using photonic switching arrays that integrate multiple-quantum-well reflection modulators and phototransistors. The switching element performs a Boolean logic A B operation on two binary input light signals that are separately incident on the phototransistor and modulator. The XOR logic function is derived by optical coupling of the switching elements. The device features high contrast that enables high-speed bit pattern matching in parallel     

A voltage source PWM rectifier-inverter with feedforward control of instantaneous power

In general, diode rectifiers with electrolytic capacitors on the dc side have been used as dc power supplies for voltage source inverters. This type of rectifiers, however, causes many problems such as poor power factor and harmonics. Recently, voltage source PWM rectifier-inverters have been studied to provide the following advantages; (1) harmonic-free on both ac sides; (2) unity power factor on the input ac side; (3) power flow of either direction or power regeneration; (4) reduction of the dc capacitor. It is, however, difficult for a conventional one to regulate the capacitor voltage on transient states because of having only a voltage feed-back loop. This paper describes a voltage source PWM rectifier-inverter with feed-forward control of instantaneous power. Based on the pq theory, the instantaneous power which is calculated in the control circuit of the inverter is fed forward to the control circuit of the rectifier. The feed-forward control of instantaneous power makes a great contribution to sufficiently suppress voltage fluctuation of the dc capacitor on transient states. Transient characteristics are discussed and some interesting experimental results of a laboratory model are shown.     

Ro separation of rare earth ions from aqueous solution by hydrous fe oxide cellulose — composite membrane

The composite membrane was prepared by impregnation of hydrous iron oxide into porous cellulose acetate membrane which served as a support. The composite membrane looks like a brownish solid solution. It has a magnetic susceptibility of 1.50 X 10^-5 emu/g. Rejection of inorganic solute was increased by impregnation. The result is to a certain extent interpreted in terms of the Donnan ion exclusion effect.