Studies of Neural Degeneration Indicate that Fasciculus Retroflexus Is a Weak Link in Brain for Many Drugs of Abuse

All studies on primary neural degeneration in the cochlea have evaluated the end stages of degeneration or the indiscriminate destruction of both sensory cells and cochlear neurons. We have developed a model which selectively simulates the dystrophic changes denoting cochlear neural degeneration while sparing the cochlear hair cells. Such a model can be used to define more precisely the mechanism of presbycusis or the hearing loss in aging man.Twenty-two pigmented guinea pigs (200-250 gm) were perfused by the perilymphatic route as live preparations using fluorocitrate in various concentrations (15-250 ug/cc) and at different incubation times (5-150 minutes). The barium salt of DL fluorocitrate, (C6H4O7F)2Ba3, was reacted with 1.0N sulfuric acid to precipitate the barium as a sulfate. The perfusion medium was prepared, just prior to use, as follows: sodium phosphate buffer 0.2M, pH 7.4 = 9cc; fluorocitrate = 15-200 mg/cc; and sucrose = 0.2M.

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Structural analysis of a Σ5 grain boundary in YBa2Cu3O7δ

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010015054x ◽

1993 ◽

Vol 51 ◽

pp. 942-943

Author(s):

J.-Y. Wang ◽

Y. Zhu ◽

A.H. King ◽

M. Suenaga

Keyword(s):

Grain Boundary ◽

Lattice Mismatch ◽

Weak Link ◽

Coincidence Site Lattice ◽

Large Angle ◽

Dislocation Core ◽

Superconducting Order Parameter ◽

Outstanding Problem ◽

Transmission Electron

One outstanding problem in YBa2Cu3O7−δ superconductors is the weak link behavior of grain boundaries, especially boundaries with a large-angle misorientation. Increasing evidence shows that lattice mismatch at the boundaries contributes to variations in oxygen and cation concentrations at the boundaries, while the strain field surrounding a dislocation core at the boundary suppresses the superconducting order parameter. Thus, understanding the structure of the grain boundary and the grain boundary dislocations (which describe the topology of the boundary) is essential in elucidating the superconducting characteristics of boundaries. Here, we discuss our study of the structure of a Σ5 grain boundary by transmission electron microscopy. The characterization of the structure of the boundary was based on the coincidence site lattice (CSL) model.Fig.l shows two-beam images of the grain boundary near the projection. An array of grain boundary dislocations, with spacings of about 30nm, is clearly visible in Fig. 1(a), but invisible in Fig. 1(b).

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Effect of thermal annealing on grain boundary chemistry of polycrystalline TiBa2Ca2Cu3Oy films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100172577 ◽

1994 ◽

Vol 52 ◽

pp. 968-969

Author(s):

Z. L. Wang ◽

C. L. Briant ◽

J. DeLuca ◽

A. Goyal ◽

D. M. Kroeger ◽

...

Keyword(s):

Grain Boundary ◽

Weak Link ◽

Zero Field ◽

Stabilized Zirconia ◽

Local Texture ◽

Transmission Electron ◽

Axis Alignment ◽

Boundary Chemistry ◽

Small Misorientation ◽

Misorientation Angles

Recent studies have shown that spray-pyrolyzed films of the Tl-1223 compound (TlxBa2Ca2Cu3Oy, with 0.7 < × < 0.95) on polycrystalline yttrium stabilized zirconia substrates can be prepared which have critical current density Jc near 105 A/cm2 at 77 K, in zero field. The films are polycrystalline, have excellent c-axis alignment, and show little evidence of weak-link behavior. Transmission electron microscopy (TEM) studies have shown that most grain boundaries have small misorientation angles. It has been found that the films have a nigh degree of local texture indicative of colonies of similarly oriented grains. It is believed that inter-colony conduction is enhanced by a percolative network of small angle boundaries at colony interfaces. It has also been found that Jc is increased by a factor of 4 - 5 after the films were annealed at 600 °C in oxygen. This study is thus carried out to determine the effect on grain boundary chemistry of the heat treatment.

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Weak Link Between Hormones, Sexual Desire

Clinical Endocrinology News ◽

10.1016/s1558-0164(06)70436-9 ◽

2006 ◽

Vol 1 (12) ◽

pp. 16

Author(s):

KATE JOHNSON

Keyword(s):

Sexual Desire ◽

Weak Link

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The Use of Prescription Drugs and Drugs of Abuse for Neuroenhancement in Europe

European Psychologist ◽

10.1027/1016-9040/a000228 ◽

2015 ◽

Vol 20 (3) ◽

pp. 155-166 ◽

Cited By ~ 45

Author(s):

Larissa J. Maier ◽

Michael P. Schaub

Keyword(s):

Prescription Drugs ◽

Illicit Drugs ◽

Adverse Reactions ◽

Low Dose ◽

Drugs Of Abuse ◽

Mental Performance ◽

Or Education ◽

Learning Techniques ◽

Monitoring The Future ◽

Definition Of

Abstract. Pharmacological neuroenhancement, defined as the misuse of prescription drugs, illicit drugs, or alcohol for the purpose of enhancing cognition, mood, or prosocial behavior, is not widespread in Europe – nevertheless, it does occur. Thus far, no drug has been proven as safe and effective for cognitive enhancement in otherwise healthy individuals. European studies have investigated the misuse of prescription and illicit stimulants to increase cognitive performance as well as the use of tranquilizers, alcohol, and cannabis to cope with stress related to work or education. Young people in educational settings report pharmacological neuroenhancement more frequently than those in other settings. Although the regular use of drugs for neuroenhancement is not common in Europe, the irregular and low-dose usage of neuroenhancers might cause adverse reactions. Previous studies have revealed that obtaining adequate amounts of sleep and using successful learning techniques effectively improve mental performance, whereas pharmacological neuroenhancement is associated with ambiguous effects. Therefore, non-substance-related alternatives should be promoted to cope with stressful situations. This paper reviews the recent research on pharmacological neuroenhancement in Europe, develops a clear definition of the substances used, and formulates recommendations for practitioners regarding how to react to requests for neuroenhancement drug prescriptions. We conclude that monitoring the future development of pharmacological neuroenhancement in Europe is important to provide effective preventive measures when required. Furthermore, substance use to cope with stress related to work or education should be studied in depth because it is likely more prevalent and dangerous than direct neuroenhancement.

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