Arches, unstable

Fig. 12.15a-c. The Tile classification. The black areas represent fracture zones. No displacement of the posterior arch. Incomplete disruption of the posterior arch (partially stable). Complete disruption of the posterior arch (unstable)... 

With RNH2 the products are also imines these, too, are usually unstable unless one of the substituents on the carbonyl carbon atom is aromatic, e.g. ArCH=NR—the stable products are then known as Schiff bases. With R2NH, the initial adduct (74) cannot lose water in the normal way some such species have been isolated but they are not particularly stable. If, however, the adduct has any a-H atoms then a different dehydration can be made to take place yielding an enamine (75) ... 

Rifkin A, Quitkin F, Carrillo C, et al. Lithium carbonate in emotionally unstable character disorder. Arch Gen Psychiatry 1972 27 519-523. 

However, these compounds are generally unstable. Most imines with a hydrogen on the nitrogen spontaneously polymerize.143 Stable hemiaminals can be prepared from polychlorinated and polyfluorinated aldehydes and ketones, and diaryl ketones do give stable imines Ar2C=NH.144 Aside from these, when stable compounds are prepared in this reaction, they are the result of combinations and condensations of one or more molecules of 12 and/or 13 with each other or with additional molecules of ammonia or carbonyl compound. The most important example of such a product is hexamethylenetetramine145 (11), prepared from ammonia and formaldehyde.146 Aromatic aldehydes give hydrobenzamides ArCH(N=CHAr)2 derived from three molecules of aldehyde and two of ammonia.147... 

Zinkham WH. Unstable hemoglobins and the selective hemolytic action of sulfonamides. Arch Intern Med 1977 137(10) 1365-6. 

O Rourke RA, Hochman JS, Cohen MC, et al. New approaches to diagnosis and management of unstable angina and non-ST-segment elevation myocardial infarction. Arch Intern Med 2001 161 674-682. 

Bearing arch status Stable Unstable Unstable... 

Storage Protect from light highly unstable may be store for a few days if kept -20 C Uses Textile and fiber bleaching, water purification, antiseptic, disinfectant, sanitizer chlorinating agent Manuf./Distrib. Arch Chems. http //www.archchemicals.com Trade Name Synonyms HyPure A [Olin/Chlor Alkali http //www.oiinchioraikaii.com], J-3 Sol n. t[Arch Chems./HTH Water Prods.]... 

Magnetic fields arch from one spot to the other. Under conditions that are poorly understood, the magnetic fields of the sunspot structures can become very unstable, ultimately producing a solar flare intense brightening of a... 

The histological structure of the carotid bodies is very typical. The chemoreceptor cell contains unstable granules that disappear when the nerve endings of the carotid bodies are stimulated. The mechanism by which the chemical stimulus is converted to an electrical impulse is not known. Aortic chemoreceptors are found between the aortic arch and the pulmonary artery on the dorsal aspect of the pulmonary artery. 

The exposed surface, whether it is an arch or a pipe, is stable when the unconfined yield strength is higher than the stress acting on the exposed surface Oj and unstable when is less than The condition for no arching or piping, therefore, is ... 

The first design for the Gateway Arch in St. Louis, Missouri, had a fatal flaw that made it unstable at the required height. The final design used 886 tons of stainless steel, making it a very expensive structure. 

Fig. 21.3. MDCT angiography in a 9-month-old infant with sudden onset of dyspnea and unstable hemodynamic situation demonstrates a double aortic arch (arrows), which leads to intermittent tracheal constriction. CT imaging was performed using short sedation without breath holding...

Rifkin A. QuitkiO F. CarillO C. Blumberg A. and Klein D. F. (1972) Lithium carbonate in emotionally unstable character disorder Arch. Gen. Psychiat. 27, 519-523. 

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