(n.) A carpentry obstruction, stockade, or other obstacle made in a passage in order to stop an enemy.
(n.) A fortress or fortified town, on the frontier of a country, commanding an avenue of approach.
(n.) A fence or railing to mark the limits of a place, or to keep back a crowd.
(n.) An any obstruction; anything which hinders approach or attack.
(n.) Any limit or boundary; a line of separation.
Example Sentences:
(1) Here we have asked whether protection from blood-borne antigens afforded by the blood-brain barrier is related to the lack of MHC expression.
(2) We conclude that chloramphenicol resistance encoded by Tn1696 is due to a permeability barrier and hypothesize that the gene from P. aeruginosa may share a common ancestral origin with these genes from other gram-negative organisms.
(3) The findings clearly reveal that only the Sertoli-Sertoli junctional site forms a restrictive barrier.
(4) This suggests that a physiological mechanism exists which can increase the barrier pressure to gastrooesophageal reflux during periods of active secretion of the stomach, as occurs in digestion.
(5) Comparison of the 50% binding concentrations of the compounds for the various PBPs of the five strains with their antibacterial activity indicates that the different antibiotics are excluded to a greater or lesser degree by the outer membrane permeability barrier and that the exclusion is most pronounced in P. aeruginosa.
(6) Preservation of dopaminergic and H1 neurotransmission, probably within the blood barrier, is needed to allow the neuroendocrine transduction of cholinergic inputs, whereas the role of 5-HT neurotransmission remains uncertain.
(7) Their levels in urine are a useful indicator of the integrity of membrane barriers of the kidney glomerular capillary wall.
(8) The IgG index (formula: see text) corrects for the influence of serum protein abnormalities as well as a bloodbrain barrier damage and is, therefore, a better measure for the presence of an IgG elevation in CSF due to IgG synthesis, when compared with other IgG quotients commonly used.
(9) In the far east is the arid, depressed country leading down Hell’s Canyon, which bottoms out at the Snake River, which the wolves crossed when they moved from Idaho, and which they now treat more as a crosswalk than a barrier.
(10) No signs of the blood-brain barrier disruption were observed.
(11) Although no anatomical 'barrier' has been described, it has been suggested that the gel mucus and epithelial phospholipids are constituents.
(12) Despite their wide dispersion, Vmax and the stereological determinations correlated strongly at 2 mo of age, confirming that Vmax is a robust indicator of the surface area of the air-blood barrier.
(13) Developmental changes are delineated, with particular reference to recent work on the ovine blood-brain barrier.
(14) Features of barrier island physiography and ecology were studied relative to selective bait deployment and site biosecurity.
(15) This study sought to determine if and why barriers to the over-the-counter purchase of syringes in the St. Louis metropolitan area might exist, given that no ordinance prohibits such a sale there.
(16) It is suggested that the intercalated disc functioned as a barrier to the freezing process.
(17) To explain some of these results a theoretical model is presented to demonstrate that while short circuiting can block the passive ionic movement, it will cause an increase in the energy consumption of the system and introduce certain important changes in the ionic barriers and e.m.fs.
(18) Our results show that paramagnetic enhancement with T1-weighted imaging adds specificity and enables rapid assessment of abnormalities of the blood-brain barrier.
(19) A functional impairment of the amino acid transport systems at the level of the blood-brain barrier seems to play a crucial role in causing deleterious modifications of the synaptic neurotransmission in the central nervous system.
(20) There was a significant correlation between the lesion index and the PD reduction, although the integrity of the resting gastric mucosal barrier remained unaltered.