fixation


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Related to fixation: nitrogen fixation, Oral fixation

fixation:

see psychoanalysispsychoanalysis,
name given by Sigmund Freud to a system of interpretation and therapeutic treatment of psychological disorders. Psychoanalysis began after Freud studied (1885–86) with the French neurologist J. M.
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.

Fixation

 

a method of preserving the structure of animal and plant cells and tissues through treatment with chemical and physical agents. Fixation is used to obtain medicinal preparations.

Physical techniques include drying and freezing at low temperatures in a vacuum (lyophilization). Specimens may be treated chemically with such reagents as formaldehyde, alcohol, acetone, and osmium tetroxide. Many reagents are used in combination with other substances, such as potassium bichromate, mercuric chloride, and picric acid; such fixatives are usually named after the researchers who proposed them, for example, Zenker’s and Maximow’s fixatives and Flemming’s, Carnoy’s, and Bouin’s solutions. The choice of technique depends on the properties and size of the specimen and the purpose of the study. For example, alcohol fixation is adequate to preserve nucleic acids, but enzyme activity is completely preserved only after lyophilization. Fixation in aldehydes is recommended for electron microscopy. Double fixation is used for better preservation of tissue, that is, primary fixation with an aldehyde fixative and a second fixation with osmium tetroxide.

REFERENCES

Roskin, G. I., and L. B. Levinson. Mikroskopicheskaia tekhnika, 3rd ed. Moscow, 1957.
Rukovodstvo po tsitologii, vol. 1. Moscow-Leningrad, 1965.

M. E. ASPIZ

fixation

[fik′sā·shən]
(psychology)
A rigid habit developed as a consequence of repeated reinforcement, or of frustration.

fixation

1. Psychol
a. the act of fixating
b. (in psychoanalytical schools) a strong attachment of a person to another person or an object in early life
2. Chem
a. the conversion of nitrogen in the air into a compound, esp a fertilizer
b. the conversion of a free element into one of its compounds
3. the reduction of a substance from a volatile or fluid form to a nonvolatile or solid form
References in periodicals archive ?
- An overview of the internal fixation devices and discussion of their role in safeguarding bones
Filipov is more gratifying as compared to conventional screw fixation mentioned in literature.
There was no statistical difference between the 2 groups' practices for fixation of explored testis in case of torsion due to hydatid (p=0.2), epididymo-orchitis (p=0.11), or no pathology (p=0.15).
Over the years, several surgical fixation techniques have been proposed.
We hypothesized that the negative postbony-fixation stress test might be a more reliable indication than the positive prebony-fixation stress test of the choice of syndesmotic fixation of PER fracture with SMM fracture and that PER ankle fractures with SMM treated with or without syndesmotic screw fixation could achieve a similar outcome.
The right of rental is the right to authorize the commercial rental to the public of the original and copies of the performance fixed in an audiovisual fixation.
The saccade length has been used to reflect the quantity of information being taken in at each fixation (Rayner, 2009).
Conclusion: This study demonstrated operative fixation of Grade III and IV anterior cruciate ligament avulsion injuries as a successful surgical option in Military soldiers.
It also gives advantage for addressing projection which is the most important aspect required attention during reduction and fixation, along with post reduction stability.
The purpose of this study was to determine whether axial and torsional stiffness of a fixed distal tibia fracture are improved by supplemental internal fixation of an associated fibular fracture.
Time taken to apply mesh was noted in minutes from laying the mesh over anterior rectus sheath to completion of fixation by either method.