Congestion

The most challenging of these applications has been the location and characterisation of anomalies in thick concrete structures using seismic methods and the detection of reinforcing steel and pre-stressing cables in congested structures using radar. 

Measuring concrete eover aecurately where reinforcement is congested and spliced... 

One precaution is that, especially with congested molecules, these potential energy loci should not be taken too literally because rotated atoms or groups (within the model) can stick during rotation, then suddenly snap into place , giving a potential energy discontinuity that has no counterpart in the real molecule. 

Concentrations in air as low as IO7 g/ms can cause lung congestion, skin damage, or eye damage. Exposure to osmium tetroxide should not exceed 0.0016 mg/ms (8-hour time weighted average - 40-hour work week). 

The cyclization to form very congested quaternary carbon centers involving the intramolecular insertion of di-, tri-, and tetrasubstituted alkenes is particularly useful for natural products synthesis[l36-138], In the total synthesis of gelsemine, the cyclization of 166 has been carried out, in which very severe steric hindrance is e.xpected. Interestingly, one stereoisomer 167... 

The chemoselective desilylation of one of the two different silyi enoi ethers in 10 to give the monosilyl enol ether II is realized by the Pd-catalyzed reaction of Bu3SnF. The chemoselectivity is controlled by steric congestion and the relative amount of the reagent[7,8]. An interesting transformation of the 6-alkoxy-2,3-dihydro-6//-pyran-3-one 12 into the cyclopentenone derivative 13 proceeds smoothly with catalysis by Pd(OAc)2 (10 mol%)[9]. 

Approach of borohydnde to the top face of the carbonyl group is sterically hindered by one of the methyl groups The bottom face of the carbonyl group is less congested and the major product is formed by hydride transfer from this direction... 

Gua/aco/ is obtained by chemical treatment of lignum vitae the wood from a species of tree that grows in warm climates It is some times used as an expectorant to help relieve bronchial congestion... 

This general behaviour is characteristic of type A, B and C bands and is further illustrated in Figure 6.34. This shows part of the infrared spectrum of fluorobenzene, a prolate asymmetric rotor. The bands at about 1156 cm, 1067 cm and 893 cm are type A, B and C bands, respectively. They show less resolved rotational stmcture than those of ethylene. The reason for this is that the molecule is much larger, resulting in far greater congestion of rotational transitions. Nevertheless, it is clear that observation of such rotational contours, and the consequent identification of the direction of the vibrational transition moment, is very useful in fhe assignmenf of vibrational modes. 

In a large molecule fhe vibrational and rofafional levels associated wifh any elecfronic sfafe become so exfremely congested af high vibrational energies fhaf fhey form a pseudo-continuum. This is illusfrafed for Sq, Si and fhe lowesf excited friplef sfafe T, lying below Sj,... 

Congestive heart failure Conglomerone [480-25-1] b-Conglycimn Conglycinin Congo Congo red... 

Toxicity. Fluorine is extremely corrosive and irritating to the skin. Inhalation at even low concentrations irritates the respiratory tract at high concentrations fluorine inhalation may result in severe lung congestion. 

Nevertheless, although the nonsedating H antihistamines have substantially improved the acceptabiUty and clinical efficacy of this class of compounds, these do not provide complete rehef eye disease responds less well than nasal disease, of the rhinitis symptoms nasal congestion responds poorly, breakthrough symptoms occur at high poUen counts, and only some 70% of patients report excellent to good treatment responses. Considerable research therefore still continues in the H antihistamine field. New antihistamines are continually being introduced. 

Oxygen inhalators are used as a first-aid measure for a long Hst of emergencies, including heart attacks and suffocation, and as a result are carried routinely by rescue squads. Oxygen—helium mixtures have proved beneficial in asthmatic attacks, because these permit more rapid flow of gas into congested areas of the respiratory system. 

The location of the pipe in the rack is selected to minimize the congestion and eliminate line crossing. If a process line connects two nozzles which are elevated higher than the piperack, then the upper level of the rack is used. Similarly, if the nozzles are both below the piperack, then the lower level rack is used. Other cases in which one nozzle is below and the other above use the least congested part of the piperack. Lines with valves are more easily accessed from the upper level, but require an access platform. 

Cardiomyopathy. Cardiomyopathy, or diseased heart muscle, may reach a point at which the heart can no longer function. It arises from a combination of factors, including hypertension, arrhythmias, and valve disease. Other problems, such as congestive heart failure, cause the interrelated heart—lung system to break down. Because the heart can no longer adequately pump, duid builds up in the lungs and other areas. 

Artificial Hearts. Congestive heart failure (CHF) is a common cause of disabiHty and death. It is estimated that three to four million Americans suffer from this condition. Medical therapy in the form of inotropic agents, diuretics (qv), and vasofilators is commonly used to treat this disorder (see Cardiovascularagents). Cardiac transplantation has become the treatment of choice for medically intractable CHF. Although the results of heart transplantation are impressive, the number of patients who might benefit far exceeds the number of potential donors. Long-term circulatory support systems may become an alternative to transplantation (5). 

Acute benzene poisoning results in CNS depression and is characterized by an initial euphoria followed by staggered gait, stupor, coma, and convulsions. Exposure to approximately 4000 ppm benzene results in complete loss of consciousness. Insomnia, agitation, headache, nausea, and drowsiness may persist for weeks after exposure (126). Continued inhalation of benzene to the point of euphoria has caused irreversible encephalopathy with tremulousness, emotional lability, and diffuse cerebral atrophy (125). In deaths arising from acute exposure, respiratory tract infection, hypo- and hyperplasia of sternal bone marrow, congested kidneys, and cerebral edema have been found at autopsy. 

Agents used in the treatment of congestive heart failure, Antiatherosclerotic agents. 

The Class I agents have many similar side effects and toxicities. The anticholinergic side effects include dry mouth, constipation, and urinary hesitancy and retention. Common gastrointestinal (GI) side effects include nausea, vomiting, diarrhea, and anorexia. Cardiovascular adverse effects are hypotension, tachycardia, arrhythmias, and myocardial depression, especially in patients with congestive heart failure. Common central nervous system (CNS) side effects are headache, dizziness, mental confusion, hallucinations, CNS stimulation, paraesthesias, and convulsions. 

Nitroglycerin remains the dmg of choice for treatment of angina pectoris. It has also been found useful for the treatment of congestive heart failure, myocardial infarction, peripheral vascular disease, such as Raynaud s disease, and mitral insufficiency, although the benefits of nitroglycerin in mitral insufficiency have been questioned. 

AGENTS USED IN THE TREATMENT OF CONGESTIVE HEART FAILURE... 

---