Direct observation of syringeal muscle function in songbirds and a parrot

2002 ◽  
Vol 205 (1) ◽  
pp. 25-35
Author(s):  
Ole Næsbye Larsen ◽  
Franz Goller
Keyword(s):  
Minor Role ◽  
Tracheal Lumen ◽  
Experimental Conditions ◽  
Cardinalis Cardinalis ◽  
Direct Observations ◽  
Adductor Muscles ◽  
Simultaneous Activation ◽  
Muscle Groups ◽  
A Minor ◽  
Aperture Control

SUMMARYThe role of syringeal muscles in controlling the aperture of the avian vocal organ, the syrinx, was evaluated directly for the first time by observing and filming through an endoscope while electrically stimulating different muscle groups of anaesthetised birds.In songbirds (brown thrashers, Toxostoma rufum, and cardinals, Cardinalis cardinalis), direct observations of the biomechanical effects of contraction largely confirm the functions of the intrinsic syringeal muscles proposed from indirect studies. Contraction of the dorsal muscles, m. syringealis dorsalis (dS) and m. tracheobronchialis dorsalis, constricts the syringeal lumen and thus reduces airflow by adducting connective tissue masses, the medial (ML) and lateral (LL) labia. Activity of the medial portion of the dS appears to affect the position of the ML and, consequently, plays a previously undescribed role in aperture control. Under the experimental conditions used in this study, full constriction of the syringeal lumen could not be achieved by stimulating adductor muscles. Full closure may require simultaneous activation of extrinsic syringeal muscles or the supine positioning of the bird may have exerted excessive tension on the syrinx. Contraction of m. tracheobronchialis ventralis enlarges the syringeal lumen and thus increases airflow by abducting the LL but does not affect the ML. The largest syringeal muscle, m. syringealis ventralis, plays a minor role, if any, in direct aperture control and thus in gating airflow.In parrots (cockatiels, Nymphicus hollandicus), direct observations show that even during quiet respiration the lateral tympaniform membranes (LTMs) are partially adducted into the tracheal lumen to form a narrow slot. Contraction of the superficial intrinsic muscle, m. syringealis superficialis, adducts the LTMs further into the tracheal lumen but does not close the syringeal aperture fully. The intrinsic deep muscle, m. syringealis profundus, abducts the LTMs through cranio-laterad movement of a paired, protruding half-ring. The weakly developed extrinsic m. sternotrachealis seems to increase tension in the ipsilateral LTM but does not move it in or out of the syringeal lumen.

Licvd of Cr(C,O) Films from Cr(CO)6 at 248 NM: Gas-Phase and Surface Processes

1988 ◽  
Vol 129 ◽  
Author(s):  
R. Nowak ◽  
L. Konstantinov ◽  
P. Hess
Keyword(s):  
Carbon Monoxide ◽  
Gas Phase ◽  
Laser Fluence ◽  
Film Deposition ◽  
Surface Processes ◽  
Minor Role ◽  
Relative Importance ◽  
Experimental Conditions ◽  
Krf Excimer Laser ◽  
A Minor

ABSTRACTThe influence of laser fluence and carbon monoxide partial pressure on the deposition rate of thin Cr(C,O) films was investigated. The films were deposited from Cr(CO)6 mixtures with CO and Ar using a KrF excimer laser. The observed results are discussed with respect to the relative importance of gasphase and surface processes. The results reveal that under the present experimental conditions chromium atoms produced in the gas phase play only a minor role as direct film precursors in KrF laser-induced film deposition.

scholarly journals Pathways of glyceride glycerol synthesis

1974 ◽  
Vol 140 (2) ◽  
pp. 249-251 ◽  
Author(s):  
Robert Rognstad ◽  
Dallas G. Clark ◽  
Joseph Katz
Keyword(s):  
Minor Role ◽  
Dihydroxyacetone Phosphate ◽  
Glycerol Phosphate ◽  
Experimental Conditions ◽  
Liver Parenchymal ◽  
Isolated Rat Liver ◽  
Glycerol Synthesis ◽  
A Minor ◽  
Parenchymal Cells ◽  
Intracellular Glycerol

Isolated rat liver parenchymal cells were incubated for various periods with [U-14C,2-3H]glycerol and the radioisotopic yields in the major products were determined, as well as the 3H/14C ratios in glyceride glycerol and intracellular glycerol phosphate. Under the conditions used (0.1mm-glycerol+10mm-l-lactate or 10mm-glycerol as substrates), only small differences were found between these 3H/14C ratios. The results suggest a minor role for a pathway of glyceride glycerol synthesis involving reduction of acylated dihydroxyacetone phosphate, under these experimental conditions.

Lateral jaw muscles of Elachistodon westermanni Reinhardt (Reptilia: Serpentes)

1976 ◽  
Vol 54 (4) ◽  
pp. 510-521 ◽  
Author(s):  
Herbert I. Rosenberg ◽  
Carl Gans
Keyword(s):  
Adductor Muscle ◽  
Minor Role ◽  
Jaw Muscles ◽  
Lower Jaw ◽  
Adductor Muscles ◽  
Harderian Glands ◽  
A Minor ◽  
Shift Of Origin ◽  
First Time ◽  
Jaw Musculature

Lateral jaw musculature of the very rare Elachistodon is described for the first time and compared with Dasypeltis. The enormous Harderian glands of both genera and their relationships with adjacent muscles are also described. Myological differences and similarities between Elachistodon, Dasypeltis, and some generalized colubrid snakes are tabulated. The primary myological differences are found in the adductor muscles of the lower jaw. Elachistodon and Dasypeltis have a single, major adductor muscle of the lower jaw, that attaches dorsally along the length of the quadrate and ventrally along the lower jaw. This muscle probably represents a fused medialis and profundus. Both species also have a small superficialis that may play a minor role in elevating the lower jaw. The reduction in size and shift of origin of the adductors is discussed in terms of functional demands associated with egg eating. Morphological similarities indicate that Elachistodon and Dasypeltis are probably related.

Tem Study of Metal Impurity Precipitates in the Surface Regions of Silicon Wafers

1987 ◽  
Vol 104 ◽  
Author(s):  
M. Seibt ◽  
K. Graff
Keyword(s):  
Particle Growth ◽  
High Resolution Electron Microscopy ◽  
Minor Role ◽  
Specimen Preparation ◽  
Dislocation Loops ◽  
Experimental Conditions ◽  
Resolution Electron ◽  
Precipitation Behaviour ◽  
Precipitation Phenomena ◽  
A Minor

ABSTRACTThe precipitation behaviour of the transition metals Co, Ni, Cu and Pd has been studied by means of conventional and high - resolution electron microscopy. Special experimental conditions for specimen preparation were chosen, which lead to the formation of haze. These conditions were the same for all metals. Therefore, a direct comparison of the respective precipitation phenomena was possible. Co and Ni were found to precipitate as Si - rich silicide particles exhibiting various morphologies attributed to different stages of particle growth and ripening. It is shown that the generation of Si- self - interstitials (and vacancies) plays a minor role in the preci-pitate formation. On the other hand Cu and Pd precipitate as metal - rich silicide particles. They form star - like colonies consisting of small particles and extended extrinsic edge - type dislocation loops. The precipitation behaviour of these two met-als is governed by the generation of Si - self - interstitials due to the large misfit of the metal - rich silicide particles.

The role of Hemolysis during Extracorporeal Homologous Liver Perfusion

1981 ◽  
Vol 4 (4) ◽  
pp. 178-185 ◽  
Author(s):  
M. Fischer ◽  
H.J. Jokiel ◽  
S. v. Sommoggy ◽  
T. Wustrow
Keyword(s):  
Liver Perfusion ◽  
Minor Role ◽  
Experimental Conditions ◽  
Volume Number ◽  
Plasma Hemoglobin ◽  
Priming Volume ◽  
Filtration Effect ◽  
Best Parameter ◽  
A Minor

The rate of hemolysis and the behaviour of platelets were investigated during extracorporeal pig liver perfusions. In 8 animals whose iliac vessels had been cannulated and which were perfused for 6 hours in our circuit, packed cell volume, number of red blood cells and concentration of hemoglobin changed moderately after hemodilution with the machine's priming volume. Similiar results were obtained in 10 pigs which were perfused with homologous isolated pig livers up to 6 hours. The best parameter to determine hemolysis was the plasma hemoglobin. Its level was twice as high as the initial value after mixture of the blood with the machine's priming volume in the iliac bypass experiments. Instead it remained practically unchanged throughout 6 hours of extracorporeal liver perfusions. The liver seemed to act as a filter under these experimental conditions. It had similar filtration effects on the enzymes LDH and alpha-HBDG which are set free in hemolysis. The decrease of platelets was more pronounced in extracorporeal liver perfusions than in iliac bypass experiments. Especially the functioning platelets decreased significantly in extracorporeal liver perfusions after 4–5 hours. The filtration effect of the liver seemed to be due to its intact RES. Xenogenous immunreactions played a minor role.

Thrombocytopenia Induced in Mice by Thromboplastin Infusion – Essential Role of the Third Complement Component

1978 ◽  
Vol 39 (03) ◽  
pp. 733-742
Author(s):  
Luis A Giraudo ◽  
Agustin P Dalmasso
Keyword(s):  
Blood Platelet ◽  
Total Serum ◽  
Minor Role ◽  
Slight Reduction ◽  
Experimental Conditions ◽  
Slow Infusion ◽  
A Minor ◽  
Deficient Mice

SummaryStudies were performed in mice to investigate the effects of the slow infusion of brain thromboplastin (tissue factor) on blood platelet levels. Thromboplastin caused pronounced thrombocytopenia in all strains of mice tested without histological evidence of intravascular coagulation. The role of the complement system in the thrombocytopenic response to thromboplastin administration was evaluated by using complement-deficient animals. Depending on experimental conditions, the degree of platelet reduction in C5-deficient mice was similar to or significantly lower than in normocomplementemic animals. C5-deficient mice reconstituted with mouse plasma or purified human C5 had a thrombocytopenic reaction identical to that of normocomplementemic controls. The thrombocytopenic response of B10.D2/new and old line mice could be abrogated by inactivating C3 with cobra venom factor prior to the administration of thromboplastin. We conclude that in mice C3 plays a central role in the thrombocytopenia induced by thromboplastin infusion, while C5 (and/or other late acting components) plays only a minor role. In vivo activation of complement by thromboplastin was indicated by the finding that thromboplastin infusion in B10.D2/new mice caused a significant reduction in total serum hemolytic complement and a slight reduction in C3 measured immunochemically. The platelet counts of uninjected B10.D2/new mice were slightly but significantly higher than in B10.D2/old mice.

The Effect of Path Length and Display Size on Memory for Spatial Information

2012 ◽  
Vol 59 (3) ◽  
pp. 147-152 ◽  
Author(s):  
Katherine Guérard ◽  
Sébastien Tremblay
Keyword(s):  
Path Length ◽  
Potential Role ◽  
Spatial Information ◽  
Recall Performance ◽  
Minor Role ◽  
Length Effect ◽  
Serial Memory ◽  
Fixed Reference ◽  
A Minor

In serial memory for spatial information, some studies showed that recall performance suffers when the distance between successive locations increases relatively to the size of the display in which they are presented (the path length effect; e.g., Parmentier et al., 2005) but not when distance is increased by enlarging the size of the display (e.g., Smyth & Scholey, 1994). In the present study, we examined the effect of varying the absolute and relative distance between to-be-remembered items on memory for spatial information. We manipulated path length using small (15″) and large (64″) screens within the same design. In two experiments, we showed that distance was disruptive mainly when it is varied relatively to a fixed reference frame, though increasing the size of the display also had a small deleterious effect on recall. The insertion of a retention interval did not influence these effects, suggesting that rehearsal plays a minor role in mediating the effects of distance on serial spatial memory. We discuss the potential role of perceptual organization in light of the pattern of results.

Use of Different Tissue Thromboplastins in the Control of Anticoagulant-Therapy

1958 ◽  
Vol 02 (05/06) ◽  
pp. 462-480 ◽  
Author(s):  
Marc Verstraete ◽  
Patricia A. Clark ◽  
Irving S. Wright
Keyword(s):  
Prothrombin Time ◽  
Anticoagulant Therapy ◽  
Factor Vii ◽  
Rabbit Brain ◽  
Minor Role ◽  
Rabbit Lung ◽  
Coagulation Mechanism ◽  
Time Test ◽  
The One ◽  
A Minor

SummaryAn analysis of the results of prothrombin time tests with different types of thromboplastins sheds some light on the problem why the administration of coumarin is difficult to standardize in different centers. Our present ideas on the subject, based on experimental data may be summarized as follows.Several factors of the clotting mechanism are influenced by coumarin derivatives. The action of some of these factors is by-passed in the 1-stage prothrombin time test. The decrease of the prothrombin and factor VII levels may be evaluated in the 1-stage prothrombin time determination (Quick-test). The prolongation of the prothrombin times are, however, predominantly due to the decrease of factor VII activity, the prothrombin content remaining around 50 per cent of normal during an adequate anticoagulant therapy. It is unlikely that this degree of depression of prothrombin is of major significance in interfering with the coagulation mechanism in the protection against thromboembolism. It may, however, play a minor role, which has yet to be evaluated quantitatively. An exact evaluation of factor VII is, therefore, important for the guidance of anticoagulant therapy and the method of choice is the one which is most sensitive to changes in factor VII concentration. The 1-stage prothrombin time test with a rabbit lung thromboplastin seems the most suitable method because rabbit brain preparations exhibit a factor VII-like activity that is not present in rabbit lung preparations.

Produktivkraft als Versprechen

2016 ◽  
Vol 46 (185) ◽  
pp. 621-638 ◽  
Author(s):  
Christian Siefkes
Keyword(s):  
Private Consumption ◽  
Minor Role ◽  
Progressive Reduction ◽  
Internal Forces ◽  
A Minor

The ‘Fragment on Machines’ from Marx’s Grundrisse is often cited as an argument that the internal forces of capitalism will lead to its doom. But the argument that the progressive reduction of labor must doom capitalism lacks a proper foundation, as a comparison with the ‘Schemes of Reproduction’ given in Capital II shows. The latter, however, aren’t fully convincing either. In reality, more depends on the private consumption of capitalists than either model recognizes. Ultimately, most can be made of the ‘Fragment on Machines’ by reading it not as an exposure of capitalism’s internal contractions, but as a discussion of a possible communist future where labor (or work) will play but a minor role.

Effects of Myo-inositol Alone and in Combination with Seleno-Lmethionine on Cadmium-Induced Testicular Damage in Mice

2019 ◽  
Vol 12 (4) ◽  
pp. 311-323 ◽  
Author(s):  
Salvatore Benvenga ◽  
Antonio Micali ◽  
Giovanni Pallio ◽  
Roberto Vita ◽  
Consuelo Malta ◽  
...  
Keyword(s):  
Structural Changes ◽  
Natural Antioxidants ◽  
Minor Role ◽  
Positive Role ◽  
Testosterone Levels ◽  
Tnf Α ◽  
Testicular Lesions ◽  
A Minor ◽  
Immunohistochemical Analyses

Background: Cadmium (Cd) impairs gametogenesis and damages the blood-testis barrier. Objective: As the primary mechanism of Cd-induced damage is oxidative stress, the effects of two natural antioxidants, myo-inositol (MI) and seleno-L-methionine (Se), were evaluated in mice testes. Methods: Eighty-four male C57 BL/6J mice were divided into twelve groups: 0.9% NaCl (vehicle; 1 ml/kg/day i.p.); Se (0.2 mg/kg/day per os); Se (0.4 mg/kg/day per os); MI (360 mg/kg/day per os); MI plus Se (0.2 mg/kg/day); MI plus Se (0.4 mg/kg/day); CdCl2 (2 mg/kg/day i.p.) plus vehicle; CdCl2 plus MI; CdCl2 plus Se (0.2 mg/kg/day); CdCl2 plus Se (0.4 mg/kg/day); CdCl2 plus MI plus Se (0.2 mg/kg/day); and CdCl2 plus MI plus Se (0.4 mg/kg/day). After 14 days, testes were processed for biochemical, structural and immunohistochemical analyses. Results: CdCl2 increased iNOS and TNF-α expression and Malondialdehyde (MDA) levels, lowered glutathione (GSH) and testosterone, induced testicular lesions, and almost eliminated claudin-11 immunoreactivity. Se administration at 0.2 or 0.4 mg/kg significantly reduced iNOS and TNF-α expression, maintained GSH, MDA and testosterone levels, structural changes and low claudin-11 immunoreactivity. MI alone or associated with Se at 0.2 or 0.4 mg/kg significantly reduced iNOS and TNF-α expression and MDA levels, increased GSH and testosterone levels, ameliorated structural organization and increased claudin-11 patches number. Conclusion: We demonstrated a protective effect of MI, a minor role of Se and an evident positive role of the association between MI and Se on Cd-induced damages of the testis. MI alone or associated with Se might protect testes in subjects exposed to toxicants, at least to those with behavior similar to Cd.

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