Bitter patterns

BITTER PATTERNS. A method for detecting domain boundaries at the surface of ferromagnetic crystals. If a drop of a colloidal suspension of ferromagnetic particles is placed on the surface of the crystals, the particles will collect along the domain boundaries where the field is strongest,... 

The zone model proposed by Brissonneau is consistent not only with his own field ion microscopic observations, but also with larger scale and often puzzling phenomena observed. PtCo magnets, for instance, form Bitter patterns on a scale quite easily visible under a light microscope. Bitter patterns do not fit the picture of a fine-particle hardening mechanism unless they also describe a larger scale phenomenon, such as Brissonneau zone boundaries. 

Bitter pattern A microscopic pattern that forms on the surface of a ferromagnetic material that has been coated with a colloidal suspension of small iron particles. The patterns outline the boundaries of the magnetic domains (see magnetism). They were first observed by F. Bitter in 1931. 

There are four methods of directly observing magnetic domains Bitter patterns, the Kerr effect, Faraday rotation, and electron microscopy. 

Bitter patterns are observed by placing a magnetic colloid containing tiny FcjO particles on the surface of the sample. The surface should be polished and etched to remove surface strains. If the surface... 

When food contains both sweet and bitter substances, the temporal pattern of reception, ie, the order in which sweet and bitter tastes are perceived, affects the total quaUtative evaluation. This temporal effect is caused by the physical location of taste buds. The buds responding to sweet are located on the surface and the tip of the tongue, the bitter in grooves toward the rear. Therefore, the two types of taste buds can be activated sequentially. 

Researchers have oscillated between emphasizing specificity of neurons ( labeled lines ) and responses to a spectrum of tastants by one cell. More recently, patterns of activation of a number of sensory cells are favored for coding specific taste sensations (Smith and Margolskee, 2001). Neural distinction of different tastes requires simultaneous activation of different cell types. The brain receives a single channel of information, simply bitter for a number of different compounds. 

Wu Zhu Yu is very pungent, bitter and hot, and enters the Liver, Spleen and Kidney meridians. It can warm the meridian, descend the Liver-Qi and treat ascending of the Liver-Qi due to excess cold in the Liver meridian. The indication is headache, particularly on the top of the head. In addition, Wu Zhu Yu can spread the Liver-Qi and can be used when the Liver-Qi attacks the Stomach, which manifests as cramping pain with a cold sensation in the Stomach and in the lateral sides of the lower abdomen, vomiting of clear fluid, and a wiry and slow pulse. This pattern can be found in disorders such as migraine, hypertension, peptic ulcer, chronic gastritis and dysmenorrhea. 

One method to realize the taste sensor may be the utilization of similar materials to biological systems as the transducer. The biological membrane is composed of proteins and lipids. Proteins are main receptors of taste substances. Especially for sour, salty, or bitter substances, the lipid-membrane part is also suggested to be the receptor site [6]. In biological taste reception, taste stimulus changes the receptor potentials of taste cells, which have various characteristics in reception [7,8]. Then the pattern constructed of receptor potentials is translated into the excitation pattern in taste neurons (across-fiber-pattem theory). 

Figure 8 shows the electrical potential pattern from 8 channels for five kinds of taste qualities of sour, salty, bitter, sweet and umami. 

The pattern of each taste substance is different, and hence each taste substance can be easily discriminated The reproducibility is very high, because the standard deviations are smaller than 1 % or so. The taste sensor shows similar response patterns to the same group of taste. As examples of sour substances, HC1, citric acid and acetic acid show similar response patterns. Bitter substances such as quinine, MgS04 and phenylthiourea show similar patterns. 

Figure 9(a) shows the response patterns to typical amino acids, each of which elicits different taste quality in humans [23]. Each channel responded to them in different ways depending on their tastes. L-Tryptophan, which elicits almost pure bitter taste, increased the potentials of channels 1, 2 and 3 greatly. This tendency was also observed for other amino acids which mainly exhibit bitter taste L-phenylalanine and L-isoleucine. L-Valine and L-methionine, which taste mainly bitter and slightly sweet, decreased the potential of channel 5 the responses of channels 1 and 2 were small. 

A typical Bitter decoration pattern for ErNi2B2C (Vinnikov et al., 2005) in the antiferromagnetic state is shown in Figure 56(a). Bands of vortices aligned along... 

Bitterness occurs as a defect in dairy products as a result of casein proteolysis by enzymes that produce bitter peptides. Bitter peptides are produced in cheese because of an undesirable pattern of hydrolysis of milk casein (Habibi-Najafi and Lee 1996). According to Ney (1979), bitterness in amino acids and peptides is related to hydrophobic-ity. Each amino acid has a hydrophobicity value (Af), which is defined as the free energy of transfer of the side chains and is based on solubility properties (Table 7-6). The average hydrophobicity of a peptide, Q, is obtained as the sum of the Af of component amino acids divided by the number of amino acid residues. Ney (1979) reported that bitterness is found only in peptides with molecular weights... 

One of the most famous sources of caffeine is chocolate, also made from the seeds of a tropical tree. Chocolate, which contains a lot of fat and is very bitter, must be mixed with sugar to make it palatable. It, too, contains a stimulating drug, and cases of chocolate dependence are easy to find. You probably know a few "chocoholics." People who regularly consume chocolate or go on chocolate-eating binges may not realize they are involved with a drug, but their consumption usually follows the same sort of pattern as with coffee, tea, and cola drinks. 

Importantly, each taste receptor cell expresses many different members of the T2R family. This pattern of expression stands in sharp contrast to the pattern of one receptor type per cell that characterizes the olfactory system (Figure 32.16). The difference in expression patterns accounts for the much greater specificity of our perceptions of smells compared with tastes. We are able to distinguish among subtly different odors because each odorant stimulates a unique pattern of neurons. In contrast, many tastants stimulate the same neurons. Thus, we perceive only "bitter" without the ability to discriminate cycloheximide from quinine. 

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