Mutual counteraction

Since a herbal combination has obvious advantages in treatment, the relationships between the herbs used in traditional Chinese medicine (TCM) have been carefully studied and certain types of relationship are identified. They are called the seven relations between herbs, e.g. mutual accentuation, mutual enhancement, mutual counteraction, mutual suppression, mutual antagonism, mutual incompatibility and single effect. Some of these are very useful in treatment, but some are harmful and therefore must be avoided. 

Of the above seven types of relationship, those of mutual accentuation and mutual enhancement are commonly used in treatment mutual counteraction and mutual suppression can also be used, especially to reduce herbs side effects or toxicity. The single herb effect is only used in a limited number of disorders relations of mutual antagonism and mutual incompatibility should be avoided in treatment. 

Mutual enhancement (Xiang Shi)/Mutual counteraction (Xiang Wei) ... 

In the case of highly polar molecules there is not even any need for coordinative interactions (e.g., hydrogen bonding) for the formation of the associates. In polar solvents, therefore, the electrostatic interactions between the molecules may also lead to dipole associates. In the associates the monomer molecules may be situated in either a parallel or an antiparallel arrangement. In the case of an antiparallel arrangement, the dipole moments of the monomer molecules are in opposite directions, whereas in a parallel arrangement they are in the same direction. If the arrangement is fully antiparallel, the directional polarization becomes zero the associated dipoles mutually counteract the effect of one another, and the polarization will be equal to the sum of the electronic and atomic polarizations. 

A typical solution present in the capillary consists of a polar solvent in which electrolytes are soluble. Low electrolyte concentrations, 10 5 to 10 3 mol 1, are typically used in ESMS. When turned on, the field Ec will penetrate the solution at the capillary tip and the positive and negative electrolyte ions in the solution will move under the influence of the field until a charge distribution results which counteracts the imposed field and leads to essentially field-free conditions inside the solution. When the capillary is the positive electrode, positive ions will have drifted downfield in the solution, i.e., toward the meniscus of the liquid, and negative ions will have drifted away from the surface. The mutual repulsion between the positive ions at the surface overcomes the surface tension of the liquid and the surface begins to expand, allowing the positive charges and liquid to move downfield. A cone forms, the so-called Taylor cone [19], and if the... 

By way of contrast, the segments are mutually repulsive in a good solvent since, by definition, contacts with solvent molecules are enthalpically favoured. This tends to cause the polymer chains to swell, a process that is counteracted by the loss in configurational entropy as the chains expand. Nonetheless, the polymer molecules are mutually repulsive so that the volume available in the polymer solution is effectively reduced below the nominal volume. This causes the effective polymer concentration to be greater than that expected for an ideal system and results in positive deviations from ideality. 

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