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In this paper we investigate the effect of Ar concentration and shadow mask material on the etch rate, surface roughness, and micromask pit density and depth for reactive ion etching (RIE) of x-cut alpha quartz. The ratio of SF6 to Ar is varied at constant power and pressure to find an optimum Ar concentration for thinning x-cut quartz while maintaining good surface quality. The recipe is used with an STS320 RIE system to produce smooth, through-hole-free, insulating quartz membranes of 7 µm thickness in selective locations on 100 µm thick x-cut quartz wafers. We demonstrate that surface quality is much improved by replacing at least 75% of the SF6 by volume with Ar, and that for non-inductively coupled plasma RIE the standard mask material nickel is detrimental to surface quality for long etch times. [ABSTRACT FROM AUTHOR]

We describe techniques for constructing single-crystal silicon high-Q torsional oscillators. The oscillators are fabricated by the high-precision micromachining of silicon using orientationdependent etches. We describe methods for using these oscillators as very powerful probes of the mechanical properties of a variety of physical systems. [ABSTRACT FROM AUTHOR]

In addition to the ω-5 olefinic acids found in other Grevillea species, about 10% of the acyl groups of G. decora seed oil contain a hydroxy group and an ω-5 double bond. The chainlengths of these acids are from C to C, with the largest concentration at the C and C chainlengths. The hydroxy group is located on odd carbons from carbon-5 through carbon-13. These acids previously were unknown in nature. The most abundant of these are 7-hydroxy- cis-17-docosenoic, 7-hydroxy- cis-19-tetracosenoic, 9-hydroxy- cis-19-tetracosenoic, 9-hydroxy- cis-21-hexacosenoic, 11-hydroxy- cis-21-hexacosenoic, and 13-hydroxy- cis-23-octacosenoic acids. The oil also contains the largest known concentration of the unoxygenated C and C ω-5 monoenes. [ABSTRACT FROM AUTHOR]

A soybean extract or an ethanolic solution of cysteine and ferric chloride catalyzed the conversion of 13-L-hydroperoxy- cis-9, trans-11-octadecadienoic acid to numerous products among which was trans-12,13-epoxy-9-hydroperoxy- trans-10-octadecenoic acid. When this fatty acid was treated further with the cysteine-ferric chloride solution, 9-hydroxy-12,13-epoxy-10-octadecenoic and 9-oxo-12,13-epoxy-10-octadecenoic acids were formed. Thus, trans-12,13-epoxy-9-hydroperoxy- trans-10-octadecenoic acid probably is an intermediate in the formation of the latter two compounds. Additionally, the erythro and threo isomers of trans-12,13-epoxy-11-hydroperoxy- cis-9-octadecenoic acid tenatatively were identified as products. [ABSTRACT FROM AUTHOR]

In the presence of oxygen, a crude soy extract converted 13-hydroperoxy- cis-9, trans-11-octadecadienoic acid into numerous products, from which 9-oxo- trans-12,13-epoxy- trans-10-octadecenoic acid was isolated. Additionally, the soy extract oxidized linoleic acid to the oxo-epoxyoctadecenoic acid, presumably via a sequential reaction involving lipoxygenase oxidation of linoleic acid followed by degradation of the resultant linoleic acid hydroperoxide. However, the linoleic acid substrate yielded two isomeric linoleic acid hydroperoxides and because of this, two isomeric oxoepoxyoctadecenoic acids. [ABSTRACT FROM AUTHOR]

Catalyzed by 10 M ionic iron in 80% ethanol, N-acetylcysteine added to linoleic acid hydroperoxide, forming a thiobond. Reaction of a specific isomer of the hydroperoxide, 13-hydroperoxy- trans-11, cis-9-octadecadienoic acid, and N-acetylcysteine, forms a number of products, of which two were identified as addition compounds. One addition product was 9- S-( N-acetylcysteine)-13-hydroxy-10-ethoxy- trans-11-octadecenoic acid, and the other was 9- S-( N-acetylcysteine)-10,13-dihydroxy- trans-11-octadecenoic acid. [ABSTRACT FROM AUTHOR]

The oil of Salvia nilotica Jacq. (Labiatae) seed contains 0.6% α-hydroxyoleic, 4.2% α-hydroxylinoleic, and 5.4% α-hydroxylinolenic acids. The first two have not been found previously in seed oils. In addition to the common fatty acids, also identified were small amounts of three unsaturated C acids and one branched chain C acid. Methyl esters of the component fatty acids were fractionated by both column and thin-layer chromatography. These esters were identified by combination of gas chromatography, GC-mass spectrometry, ozonolysis-GC, infrared, and nuclear magnetic resonance. [ABSTRACT FROM AUTHOR]

cis-5, cis-9-Octadecadienoic acid (2.7%) and cis-5, cis-9, cis-12-octadecatrienoic acid (24.9%) are present in the seed oil of Larix leptolepis. The double bond positions were identified by ozonolysis and by gas chromatography-mass spectrometry of methoxy derivatives. Small quantities of branched chain acids of various chain lengths were indicated by gas chromatography. The presence of C and C branched methyl esters was confirmed by gas chromatography-mass spectrometry. [ABSTRACT FROM AUTHOR]

The seed oil of Celastrus orbiculatus (family Celastraceae) was reinvestigated to determine whether the benzoic acid that it contains is esterified with glycerol. Unlike acetic acid, benzoic acid is not incorporated in glycerides of this oil but, instead, is esterified with two sesquiterpenoid triols of the empirical formula CHO. trans-Cinnamic acid also is esterified with these triols. Acetic acid is a component of these nonglyceride esters, as well as of the triglycerides. We found no evidence for the occurrence of formic acid in this oil. By countercurrent fractionation, we found that this oil contains 8% 'ordinary' triglycerides, 59% mono-acetotriglycerides, and 33% nonglyceride substances. [ABSTRACT FROM AUTHOR]

Routine analysis of fatty ester fractions of Lesquerella fendleri oil suggested the presence of epoxy compounds and other minor components. By a combination of open silica column and high performance liquid chromatography (HPLC) fractionations of the methyl esters prepared from the oil, these constitutents were isolated and then characterized by thin-layer chromatography-mass spectrometry (GC-MS-electron ionization, EI, and chemical ionization, CI) and nuclear magnetic resonance (NMR-H andC). Three epoxy acids, 15,16-epoxy-9,12-octadecadienoic, 9,10-epoxy-12-octadecenoic and 9,10-epoxy-octadecanoic, were found. Hydroxy acids present included a C-22 homologue of lesquerolic acid (16-hydroxy-12-docosenoic acid) and 14,15-dihydroxy-tricosanoic acid. Other minor ocmponents included four sterols, brassicasterol, campesterol, β-sitosterol and stigmasterol, and a series of saturated and unsaturated fatty acids up to C30. [ABSTRACT FROM AUTHOR]

Significant genetic variation for lauric acid (12∶0) and capric acid (10∶0) composition and seed weight was measured within lauric acid-rich, self-pollinating germplasm accessions of Cuphea wrightii, C. tolucana, and C. lutea. Means and ranges of individual plant progenies for 12∶0 content of C. wrightii accessions was 60.5±.63% (49.8±65.8%), 10∶0 content was 23.7±.54% (18.6±33.0%), and 1000-seed weight was 1.50±.03 g (1.20-2.47 g). Progenies of single plant selections carried to the S generation exhibited reduced variability within selections, but significant variation among selections for 12∶0, 10∶0 and 1000-seed weight. Variation among single plant selections of C. tolucana was less than that of C. wrightii and attributed to a restricted germplasm base. Means and ranges for 12∶0 content were 61.6±.47% (59.2-69.9%), 10∶0 was 22.3±.62% (11.7-25.3%), and 1000-seed weight was 1.40±.05 g (0.90-1.69 g). Cuphea lutea has a significantly different 12∶0−10∶0 profile than the other lauric acid-rich species. Means and ranges for 12∶0 were 36.8±.14% (33.7-40.8%), 10∶0 was 21.8±.08% (16.4-23.9%), 1000-seed weight was 2.26±.02 g (1.82-272 g). The 1000-seed weight was highly positively correlated with 8∶0, 10∶0, 18∶1 and 18∶2 contents and highly negatively correlated with 12∶0, 14∶0 and 16∶0 in both C. wrightii and C. tolucana. No such relationship was found for C. lutea. A highly significant negative correlation was also measured for 12∶0 and 10∶0 contents in C. wrightii and C. tolucana. [ABSTRACT FROM AUTHOR]