Mechanical constrictive effect

These compounds are the first examples for the stabilization of the LS state of iron(II) with saturated nitrogen as the most abundant donors this has been ascribed by the authors to the enhanced ligand field strength due to the constrictive effect of the mechanically confining in-plane macrocyclic ligand . Six-coordinate iron(II) complexes are formed with relatively weak axial ligands such as X = CH3C002 >... 

Analysis on the Basis of Bubble Dynamics The bubble behavior and hence the pressure pulse generated at the collapse of the cavity in the case of hydrodynamic cavitation depends upon the operating conditions as well as the geometry of the mechanical constriction that results in the generation of cavitating conditions downstream of the orifice. Thus, as a first step towards the design of hydrodynamic-cavitation reactors, it is important to understand the relationship between the cavity behavior and the operating parameters and possibly quantify the intensity of cavitation and then the net cavitational effects as a direct function... 

Primary irritants cause inflammation. Inflammation is one of the body s defence mechanisms. It is the reaction of a tissue to harm which is insufficient to kill the tissue and is typified by constriction of the small vessels in the affected area, dilation of the blood vessels, increased permeability of the vessel walls, and migration of the white blood and other defensive cells to the invading harmful chemical. The aim is to concentrate water and protein in the affected area to dilute the effect and wash away the chemical. Production of new cells is speeded up and contaminated surface cells are shed. 

Rapid-acting neurotoxin that causes irreversible depolarization of neural and muscular tissue by an unknown mechanism. It has a very potent effect on coronary arteries and death may result from constriction of the blood vessels of the heart. It is a solid obtained from bacterium associated with soft corals (Palythoa caribaerum and Palythoa toxica). It is soluble in water and alcohol, and stable to heat. 

Because the respiratory tract is an initial target of any air pollutant challenge, it usually receives primary attention in tests to determine irritant effects of exposure. Other aspects of interest include hematology, blood enzyme biochemistry, eye irritation, and p chomotor performance. Constriction of the large airways, maldistribution of ventilation due to narrowing in some small airways, constriction of peripheral lung units, and mechanical or gas diffusion impairment due to edema are possible effects of insult by pollutants. A variety of pulmonary tests is required to examine the possibilities. 

Mechanism of Action An antihypertensive that blocks endothelin-l, the neurohormone that constricts pulmonary arteries. Therapeutic Effect Improves exercise ability and slows clinical worsening of pulmonary arterial hypertension (PAH). Pharmacokinetics Highlybound to plasma proteins, mainlyalbumin. Metabolized in the liver. Eliminated by biliary excretion. Half-life Approximately 5 hr. 

Mechanism of Action A parasympathetic, anticholinesterase agent that inhibits destruction of acetylcholine by acetylcholinesterase, thus causing accumulation of acetylcholine at cholinergic synapses. Results in an increase in cholinergic responses such as miosis, increased tonus of intestinal and skeletal muscles, bronchial and ureteral constriction, bradycardia, and increased salivary and sweat gland secretions. Therapeutic Effect Diagnosis of myasthenia gravis. 

Mechanism of Action A direct-acting sympathomimetic amine that acts on alpha-adrenergic receptors in arterioles of the nasal mucosa to produce constriction. Therapeutic Effect Causes vasoconstriction resulting in decreased blood flow and decreased nasal congestion. 

Mechanism of Action A vasoconstrictor that stimulates alpha-adrenergic receptors in sympathetic nervous system. Constricts arterioles. Therapeutic Effect Reduces redness, irritation, and congestion. 

The mechanical stability of PSM and AMM-5 samples was investigated by pressing the sample in a die (having a diameter of 16 mm) under different pressures for 15 min. The effects of compression on the surface areas and pore properties of the materials are shown in Table 1. It can be seen that the surface areas of both PSM and AMM-5 samples decrease under high pressure compression. The decrease of surface area, which is proportional to the pressure exerted on the samples, is accompanied with the decrease of pore volume, with no obvious decrease of the pore diameter for both samples. The results indicate that, under high pressure compression, some of the mesoporous channels of MCM-41 have collapsed completely and not constricted to pores of smaller diameter. 

Another major concern for toxicity of vigabatrin is sever persistent visual field constriction associated with retinal cone system dysfunction [63, 82], The effect did not appear to be reversible upon discontinuation of the drug. Vigabatrin also causes GABA to accumulate in retinal glial cells in rats, suggesting a mechanism for the toxic effect [83]. 

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