ANALYSIS OF NATURALLY OCCURRING PHENOLIC COMPOUNDS IN AROMATIC PLANTS BY RP-HPLC AND GC-MS AFTER SILYLATION

Aromatic plants of Greek origin, Origanum dictamnus (dictamus), Eucalyptus globulus (eucalyptus), Origanum vulgare L. (oregano), Mellisa officinalis L. (balm mint) and Sideritis cretica (mountain tea) were examined for the content of phenolic substances. Reversed phase high performance liquid chromatography was used for the analysis of the plant extracts. Gas chromatography–mass spectrometry method was also used for identification of phenolic compounds after silylation. The most abundant phenolic acids were gallic acid (1.5–2.6 mg 100 g ^{− 1} dry sample), ferulic acid (0.34–6.9 mg 100 g ^{− 1} dry sample) and caffeic acid (1.0–13.8 mg 100 g ^{− 1} dry sample). ( + )-Catechin and ( − )-epicatechin were the main flavonoids identified in oregano and mountain tea. Quercetin was detected only in eucalyptus and mountain tea.

PRACTICAL APPLICATIONS

Plant-derived polyphenols receive considerable interest because of their potential antioxidant and antimicrobial properties. Undoubtedly, it is very important not only to determine those properties but also to determine each and every phenol in aromatic plants both qualitatively and quantitatively. A number of analytical methods have been proposed for the separation and determination of these compounds. Most of these protocols are based on a high performance liquid chromatography technique with ultraviolet spectrophotometry. Gas chromatography–mass spectrometry after silylation of the phenolic compounds is used in this research together with the aforementioned technique as an alternative and more sensitive method to detect and understand the compositional profile of the extracts as well as the structure and functional relationship of the components in the extracts, based on MS spectra.     

Use of Magnetic Resonance Procedures for Measurement of Oil in French-style Dressings

Magnetic resonance imaging and spectroscopy techniques have been developed for measuring percentage of edible oil in French-style salad dressings. In imaging, one takes advantage of the variations in signal intensities related to differences in relaxation times of the oil and aqueous phases, and of the proportionality of projected frequencies to spatial distribution of sample constituents. In spectroscopy, percentage of oil is determined from standard curves where the integrals of oil/ total spectra are correlated to known amounts of oil in standard preparations. Both procedures permit rapid, nondestructive analysis of commercially packaged dressings in unopened bottles with nonmagnetic closures. Results obtained in imaging or by NMR spectroscopy were within ± 2% of the expected values.     

优化车刀大幅度提高生产效率

大量生产有其自身规律.因此对于一、二百万件的批量生产,需要在很长的一段时间内始终保持加工的质量标准.首要考虑的是存在多少影响变量.在很多情况下,机床的温度变化可能完全不同,刀具对加工表面的影响无法预测,不同批次的原材料也不可能完全一样等等.每周七天,一年365天,机床的运行状态也是无法控制的.     

IS THE ST. LOUIS REDEVELOPMENT PROGRAM FISCALLY BENEFICIAL?

ABSTRACT: St. Louis is one of many U.S. cities suffering from urban decay and fiscal crisis. To resolve these problems, the city has adopted a redevelopment program under Missouri State Statute 353. This Chapter 353 program grants private developers 25 years of tax abatement for making property improvements and permits them to accumulate property through the exercise of eminent domain. The program includes the city's entire central business district and has been extended to cover residential areas. This article discusses the research study on which this Chapter 353 program was based, points out a number of serious problems, and concludes that the program may, in fact, further reduce the city's fiscal integrity.     

ABSORPTION OF VANADIUM, NICKEL, ALUMINUM AND MOLYBDENUM BY SWISS CHARD GROWN ON SOIL AMENDED WITH OIL FLY ASH OR BOTTOM ASH

An appreciable percentage of electric power is generated by oil-fired power plants. The ash resulting from such plants is typically very high in elements such as vanadium, nickel, aluminum and molybdenum. Oil bottom ash and fly ash when disposed or fly ash fallout from such power plants could result in absorption of such metals by agricultural crops. Swiss chard (Beta vulgaris L.) was grown in potted soils amended with oil bottom ash and fly ash at 2% and 1% (w/w), respectively. The crop absorbed significantly higher concentrations of each of the metals as compared to those in the control crop grown on soil alone. Higher levels of the ashes in soil resulted in phytotoxicity to the swiss chard .     

Meter as Mechanism: A Neural Network Model that Learns Metrical Patterns

One kind of prosodic structure that apparently underlies both music and some examples of speech production is meter. Yet detailed measurements of the timing of both music and speech show that the nested periodicities that define metrical structure can be quite noisy in time. What kind of system could produce or perceive such variable metrical timing patterns? And what would it take to be able to store and reproduce particular metrical patterns from long-term memory? We have developed a network of coupled oscillators that both produces and perceives patterns of pulses that conform to particular meters. In addition, beginning with an initial state with no biases, it can learn to prefer the particular meter that it has been previously exposed to.