Brief exposure

Another version of the o-aminobenzyl anion synthon is obtained by dilithi-ation of A-f-Boc-protected o-alkylanilines. These intermediates are C-acylated by DMF or A"-methoxy-At-melhyl carboxamides, leading to either 3- or 2,3-disubstituted indoles. In this procedure dehydration is not spontaneous but occurs on brief exposure of the cyelization product to acid[4]. Use of CO as the electrophile generates oxindoles. 

An important chemical finishing process for cotton fabrics is that of mercerization, which improves strength, luster, and dye receptivity. Mercerization iavolves brief exposure of the fabric under tension to concentrated (20—25 wt %) NaOH solution (14). In this treatment, the cotton fibers become more circular ia cross-section and smoother ia surface appearance, which iacreases their luster. At the molecular level, mercerization causes a decrease ia the degree of crystallinity and a transformation of the cellulose crystal form. These fine stmctural changes iacrease the moisture and dye absorption properties of the fiber. Biopolishing is a relatively new treatment of cotton fabrics, involving ceUulase enzymes, to produce special surface effects (15). 

In the past, chloroform was used extensively as a surgical anesthetic, but this use was abandoned because exposure to narcotic concentrations often resulted in sudden death from effects on the heart and circulation or from severe injury to the Hver. In addition, chloroform for this and other consumer uses was harmed by FDA in 1976 with the discovery that it is carcinogenic in mice (38). When splashed into the eye, chloroform causes local pain and irritation, but serious injury is not expected. Skin contact for single, brief exposures ordinarily causes Htde or no local irritation. 

Overexposure to tetrachloroethylene by inhalation affects the central nervous system and the Hver. Dizziness, headache, confusion, nausea, and eye and mucous tissue irritation occur during prolonged exposure to vapor concentrations of 200 ppm (15). These effects are intensified and include incoordination and dmnkenness at concentrations in excess of 600 ppm. At concentrations in excess of 1000 ppm the anesthetic and respiratory depression effects can cause unconsciousness and death. A single, brief exposure to concentrations above 6000 ppm can be immediately dangerous to life. Reversible changes to the Hver have been reported foUowing prolonged exposures to concentrations in excess of 200 ppm (16—22). Alcohol consumed before or after exposure may increase adverse effects. 

Note that localized corrosion having the appearance illustrated in Figs. 12.18 through 12.20 could be associated with brief exposure to a strong acid. In this case, however, all available information indicated that the tubes had never been exposed to an acid of any type. Cavitation was caused by high-frequency vibration of the tubes. The vibration apparently induced a threshold cavitation intensity such that rough or irregular surfaces produced cavitation bubbles, and smooth internal surfaces did not. 

Speeifie short-term exposure limits are listed by the HSE for those ehemieals whieh pose a risk of aeute effeets sueh as eye irritation from brief exposures. Eor other ehemieals a reeommended... 

Exposure to sulfur dioxide in the ambient air has been associated with reduced lung function, increased incidence of respiratory symptoms and diseases, irritation of the eyes, nose, and throat, and premature mortality. Children, the elderly, and those already suffering from respiratory ailments, such as asthmatics, are especially at risk. Health impacts appear to be linked especially to brief exposures to ambient concentrations above 1,000 ixg/in (acute exposures measured over 10 minutes). Some epidemiologic studies, however, have shown an association between relatively low annual mean levels and excess mortality. It is not clear whether long-... 

Tlie following are the typical reactions of the dithietane 73. Treatment of 73 with PI13P led to the loss of one sulfur and the formation of the rearrangement products 121 and 122. Treatment with PhS resulted in the formation of 123, whereas brief exposure to NaBFL, followed by trapping with Mel led to the novel episulhdes 124 and 125 and the alkene 126. 

Extremely poisonous V small concns are fatal after brief exposure Refs 1) Gmelin, Syst Nr 26 (1930), 82-91 2) O. Hijnigschmid T. Johannsen, ZNatur-forsch 1, 650 (1946) not found in CA 3) G. Brauer, Ed, Handbook of Preparative Inorganic Chemistry , Vol 1, Academic Press, NY (1963), 893—4 4) Merck (1968), 144 5) Sax... 

Historically, storability, ignitibility and burn time have been recurring problems in tracer munition fabrication. The endothermic decompn of metal salt oxidizers and the brief exposure to the propint flame (0.5j-2msec) brought about the need for special igniters and... 

Griseofulvin Beneficial effects may not be noticed for some time tiierefore, take the drug for die full course of dierapy. Avoid exposure to sunlight and sunlamps because an exaggerated skin reaction (which is similar to a severe sunburn) may occur even after a brief exposure to ultraviolet light. 

Doxycycline This drug can cause photosensitivity. Even relatively brief exposure to sunlight may cause sunburn. Avoid exposure to die sun by wearing protective clodiing (eg, long-sleeved shirts and wide-brimmed hats) and by using a sunscreen. 

Some antihistamines may cause dizziness, disturbed coordination, fatigue, hypotension, headache, epigastric distress, and photosensitivity (exaggerated response to brief exposure to the sun, resulting in moderately severe to severe sunburn). 

From this brief exposure to the pervasive character of metal-vapor cryochemistry and matrix-isolation spectroscopy, it is clear that a field of multidisciplinary concern is surveyed. However, in this review, we shall focus on those accomplishments of greatest interest to the inorganic community in general, while pointing out, where applicable, the relevance of the results to other branches of chemistry and physics. 

Dimethylphenols yield turquoise-colored chromatogram zones on a violet background, that are converted to blue-violet zones on a flesh-colored background on brief exposure to ammonia vapor. 

Brief exposure to nitrous fumes (up to 3 min) leaves the fluorescent power of the acid-instable fluorescence indicator 254. incorporated into most TLC layers, largely unaffected, so that the nitroaromatics so formed can be detected as dark zones on a green fluorescent background [1]. For purposes of in situ quantitation it is recommended that the fluorescence indicator be destroyed by 10 min exposure to nitrous fumes in order to avoid difficulties in the subsequent evaluation [1]. 

In the presence of air, the roots, coleoptile, mesocotyl, endosperm, scutellum, and anther wall of maize synthesise a tissue-specific spectrum of polypeptides. The scutellum and endosperm of the immature kernel synthesise many or all of the ANPs constitutively, along with many other proteins under aerobic conditions. Under anaerobic conditions all of the above organs selectively synthesise only the ANPs. Moreover, except for a few characteristic qualitative and quantitative differences, the patterns of anaerobic protein synthesis in these diverse organs are remarkably similar (Okimoto et al., 1980). On the other hand, maize leaves, which have emerged from the coleoptile, do not incorporate labelled amino acids under anaerobic conditions and do not survive even a brief exposure to anaerobiosis (Okimoto et al., 1980). 

The study of a CuO/ZnO/AlaOs methanol synthesis catalyst showed the working catalyst surface under our experimental conditions to consist of metallic Cu, ZnO, and Al Os. Brief exposure of such catalysts to air results In Instant formation of a few percent Cu+l. Thus, the use of a combined reactlon/analysls system as described here is absolutely essential In surface analytical studies of reactive catalyst surfaces. 

The acceptable limits for toxic exposure depend on whether the exposure is brief or prolonged. Lethal concentration for airborne materials and lethal dose for non-airbome materials are measured by tests on animals. The limits for brief exposure to toxic materials that are airborne are usually measured by the concentration of toxicant that is lethal to 50% of the test group over a given... 

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