Effect of methacholine chloride on rheology and transport of canine tracheal mucus

1979 ◽  
Vol 47 (1) ◽  
pp. 26-31 ◽  
Author(s):  
M. King ◽  
N. Viires
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Base Line ◽  
Low Doses ◽  
Mucociliary Transport ◽  
Frog Palate ◽  
High Doses ◽  
Tracheal Mucus ◽  
Higher Doses ◽  
Cytology Brush

The effect of methacholine chloride (M) on tracheal mucus was investigated in three conscious tracheostomized dogs. Aerosols of M in concentrations of 2--32 mg/ml were delivered intratracheally for 1 min. Mucus was sampled with a cytology brush at 2 min postchallenge and at irregular intervals thereafter. The mechanical properties of each sample were determined in the magnetic microrheometer, and correlated with mucociliary transportability as assayed by the frog palate technique. With high doses of M, there was an increase in volume of secretion collected per unit time. The elastic modulus (G′) at 2 min postchallenge went up (to 1.5 x 2.3 x control for 16 and 32 mg/ml, respectively) then fell below control before returning to base line after 30 or 45 min. With low doses of M (2--8 mg/ml) the secretion rate was also above control, but only a decrease in G′ (to 0.54 x control) was observed. The decrease in G′ at low doses did not significantly alter the frog palate transport rate; however, the increase at higher doses did impede mucociliary transport.

Morphology-Property Relationships in EPDM-Polybutadiene Blends

1982 ◽  
Vol 55 (1) ◽  
pp. 151-160 ◽  
Author(s):  
Gary R. Hamed
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Interfacial Adhesion ◽  
Pure Component ◽  
Dispersed Phase ◽  
Minor Effect ◽  
Low Doses ◽  
High Doses ◽  
A Minor ◽  
Higher Doses

Abstract When mixing EPDM and BR in the Brabender a heterogeneous blend results; the dispersed phase is first sheared into fibrous strands and then broken down into micron sized particles. At low doses of irradiation, the morphology of the blend only has a minor effect on the energy to break, whereas at high doses the Eb may increase by a factor of three as the dispersed particle size is reduced from the 100 micron range. The Eb of the blend is the weight-average of the two pure components at low doses (independent of morphology), but is greater than either pure component at higher doses. Interfacial adhesion may play a key role in determining the mechanical properties in rubbery blends.

Effect of naloxone on ethanol- and pentobarbital-induced narcosis

1982 ◽  
Vol 60 (10) ◽  
pp. 1315-1318 ◽  
Author(s):  
J. M. Khanna ◽  
J. M. Mayer ◽  
H. Kalant ◽  
G. Shah
Keyword(s):  
Sleep Duration ◽  
Low Doses ◽  
Small Reduction ◽  
High Doses ◽  
Higher Doses ◽  
Convulsant Effect

Single or repeated subcutaneous administrations of naloxone in doses of up to 4 mg∙kg−1 did not alter the time for onset or the duration of ethanol- or pentobarbital-induced narcosis in rats. An increase in the naloxone dosage to 50 mg∙kg−1 s.c. resulted in a small reduction of ethanol-induced sleep duration. Repeated i.p. or i.v. administrations of much higher doses of naloxone (300–400 mg∙kg−1 and 120–180 mg∙kg−1, respectively) did produce significant reductions in ethanol-induced narcosis. However, similar naloxone doses, when administered alone, i.v., had marked convulsant effect. It appears that naloxone, in low doses, is not an effective antidote for narcosis caused by ethanol or pentobarbital at the ethanol and pentobarbital doses tested, whereas the antagonism of ethanol-induced sleep by high doses of naloxone may be due to the analeptic action of this drug.

Evaluation of Mechanical Properties of Surface Layer Injection Molded Polypropylene by Nanoindentation Test

2016 ◽  
Vol 699 ◽  
pp. 86-90
Author(s):  
David Manas ◽  
Miroslav Manas ◽  
Martin Ovsik ◽  
Michal Stanek ◽  
Pavel Stoklasek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Layer ◽  
Elastic Modulus ◽  
Considerable Increase ◽  
Hardness Test ◽  
Beta Radiation ◽  
Nanoindentation Test ◽  
Indentation Hardness ◽  
Low Doses ◽  
Injection Molded

The influence of beta radiation on the changes in the structure and selected properties (mechanical and thermal) polymers were proved. The use of low doses of beta radiation for polypropylene and its influence on the changes of micro, macro mechanical properties was thoroughly studied. The specimens of polypropylene were made by injection molding technology and irradiated by low doses of beta radiation (0, 15 and 33 kGy). The changes in the microstructure and micromechanical properties of surface layer were evaluated using WAXS and instrumented nano hardness test. The results of the measurements showed considerable increase in mechanical properties (indentation hardness, indentation elastic modulus) when the beta radiation are used.

Mechanism of Action of Trazodone: a Multifunctional Drug

CNS Spectrums ◽  
2009 ◽  
Vol 14 (10) ◽  
pp. 536-546 ◽  
Author(s):  
Stephen M. Stahl
Keyword(s):  
Controlled Release ◽  
Adrenergic Receptors ◽  
Low Dose ◽  
Low Doses ◽  
Release Formulation ◽  
Therapeutic Mechanism ◽  
High Doses ◽  
Pharmacologic Actions ◽  
Dose Dependent ◽  
Higher Doses

Multifunctional drugs are those with more than one therapeutic mechanism. Trazodone is a multifunctional drug with dose-dependent pharmacologic actions. That is, it has hypnotic actions at low doses due to blockade of 5-HT2A receptors, as well as H1 histamine receptors and α1 adrenergic receptors. Higher doses recruit the blockade of the serotonin transporter (SERT) and turn trazodone into an antidepressant. Although trazodone has traditionally been used as a low dose hypnotic, a new controlled release formulation that has the potential to improve the tolerability of high doses may provide an opportunity to revisit this multifunctional drug as an antidepressant as well.

Involvement of 5-Hydroxytryptamine in Platelet Aggregation In Vivo in Rats and Guinea Pigs

1989 ◽  
Vol 61 (03) ◽  
pp. 463-467 ◽  
Author(s):  
G M Smith
Keyword(s):  
Platelet Count ◽  
Guinea Pigs ◽  
Platelet Adhesion ◽  
Adenosine Diphosphate ◽  
Rate Of Return ◽  
Low Doses ◽  
Dose Dependent ◽  
Higher Doses ◽  
Rat Platelets

SummaryIn this study, 5-hydroxytryptamine (5-HT) caused a dose- dependent fall in the circulating platelet count suggesting that 5-HT receptors are activated in rat platelets to cause platelet adhesion and aggregation. When low doses of adenosine diphosphate (ADP) were simultaneously injected with 5-HT, there was a significant potentiation of the responses to ADR Ketanserin significantly reduced the potentiated responses. When higher doses of ADP were infused with bolus injections of 5-HT there was no potentiation and ketanserin did not reduce these responses. Ketanserin did not inhibit the collagen-induced fall in circulating platelet count, but did significantly increase the rate of return to the basal platelet count compared with control. 5-HT did not cause a fall in platelet count in guinea-pigs

ANTAGONISTIC ACTION OF NORETHYNODREL ON THE TESTOSTERONE-DEPENDENT PROCESS OF FRUCTOSE FORMATION IN MOUSE SEX ACCESSORY ORGANS

1966 ◽  
Vol 51 (2) ◽  
pp. 224-230 ◽  
Author(s):  
John A. Thomas ◽  
Edward T. Knych
Keyword(s):  
Antagonistic Activity ◽  
Low Doses ◽  
Antagonistic Action ◽  
Dependent Process ◽  
High Doses

ABSTRACT Norethynodrel antagonized the fructose stimulating effects of exogenous testosterone in sex accessory organs of castrate mice. It was antiandrogenic at both low doses (50 μg) and high doses (400 μg) of testosterone. Norethindrone and ethisterone suppressed fructose formation in the testosterone-treated castrate mouse, but not as effectively as norethynodrel. Norethandrolone exerted no antagonistic activity.

scholarly journals Experimental Analysis of the Mechanical Properties and Resistivity of Tectonic Coal Samples with Different Particle Sizes

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2303
Author(s):  
Congyu Zhong ◽  
Liwen Cao ◽  
Jishi Geng ◽  
Zhihao Jiang ◽  
Shuai Zhang
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Uniaxial Compressive Strength ◽  
Coalbed Methane ◽  
Coal Sample ◽  
Fine Particles ◽  
Particle Sizes ◽  
Tectonic Coal

Because of its weak cementation and abundant pores and cracks, it is difficult to obtain suitable samples of tectonic coal to test its mechanical properties. Therefore, the research and development of coalbed methane drilling and mining technology are restricted. In this study, tectonic coal samples are remodeled with different particle sizes to test the mechanical parameters and loading resistivity. The research results show that the particle size and gradation of tectonic coal significantly impact its uniaxial compressive strength and elastic modulus and affect changes in resistivity. As the converted particle size increases, the uniaxial compressive strength and elastic modulus decrease first and then tend to remain unchanged. The strength of the single-particle gradation coal sample decreases from 0.867 to 0.433 MPa and the elastic modulus decreases from 59.28 to 41.63 MPa with increasing particle size. The change in resistivity of the coal sample increases with increasing particle size, and the degree of resistivity variation decreases during the coal sample failure stage. In composite-particle gradation, the proportion of fine particles in the tectonic coal sample increases from 33% to 80%. Its strength and elastic modulus increase from 0.996 to 1.31 MPa and 83.96 to 125.4 MPa, respectively, and the resistivity change degree decreases. The proportion of medium particles or coarse particles increases, and the sample strength, elastic modulus, and resistivity changes all decrease.

scholarly journals Experimental and Numerical Analysis of the Mechanical Properties of a Pretreated Shape Memory Alloy Wire in a Self-Centering Steel Brace

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 80
Author(s):  
Bo Zhang ◽  
Sizhi Zeng ◽  
Fenghua Tang ◽  
Shujun Hu ◽  
Qiang Zhou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Energy Dissipation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Loading Rate ◽  
Effective Elastic Modulus ◽  
Maximum Energy ◽  
Numerical Results ◽  
Energy Dissipation Capacity

As a stimulus-sensitive material, the difference in composition, fabrication process, and influencing factors will have a great effect on the mechanical properties of a superelastic Ni-Ti shape memory alloy (SMA) wire, so the seismic performance of the self-centering steel brace with SMA wires may not be accurately obtained. In this paper, the cyclic tensile tests of a kind of SMA wire with a 1 mm diameter and special element composition were tested under multi-working conditions, which were pretreated by first tensioning to the 0.06 strain amplitude for 40 cycles, so the mechanical properties of the pretreated SMA wires can be simulated in detail. The accuracy of the numerical results with the improved model of Graesser’s theory was verified by a comparison to the experimental results. The experimental results show that the number of cycles has no significant effect on the mechanical properties of SMA wires after a certain number of cyclic tensile training. With the loading rate increasing, the pinch effect of the hysteresis curves will be enlarged, while the effective elastic modulus and slope of the transformation stresses in the process of loading and unloading are also increased, and the maximum energy dissipation capacity of the SMA wires appears at a loading rate of 0.675 mm/s. Moreover, with the initial strain increasing, the slope of the transformation stresses in the process of loading is increased, while the effective elastic modulus and slope of the transformation stresses in the process of unloading are decreased, and the maximum energy dissipation capacity appears at the initial strain of 0.0075. In addition, a good agreement between the test and numerical results is obtained by comparing with the hysteresis curves and energy dissipation values, so the numerical model is useful to predict the stress–strain relations at different stages. The test and numerical results will also provide a basis for the design of corresponding self-centering steel dampers.

Mechanical Properties of Secondary Wall and Compound Corner Middle Lamella near the Phenol-Formaldehyde (PF) Adhesive Bond Line Measured by Nanoindentation

2011 ◽  
Vol 236-238 ◽  
pp. 1746-1751 ◽  
Author(s):  
Kun Liang ◽  
Guan Ben Du ◽  
Omid Hosseinaei ◽  
Si Qun Wang ◽  
Hui Wang
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Secondary Wall ◽  
Phenol Formaldehyde ◽  
Middle Lamella ◽  
Adhesive Bond ◽  
Cellular Level ◽  
Bond Line ◽  
Line Region ◽  
Penetration Behavior

To find out the penetration of PF into the wood cell wall and its effects onthe mechanical properties in the cellular level, the elastic modulus and hardness of secondary wall (S2layer) and compound corner middle lamella (CCML) near PF bond line region were determined by nanoindentation. Compare to the reference cell walls (unaffected by PF), PF penetration into the wood tissues showed improved elastic modulus and hardness. And the mechanical properties decreased slowly with the increasing the distance from the bond line, which are attributed to the effects of PF penetration into S2layer and CCML. The reduced elastic modulus variations were from18.8 to 14.4 GPa for S2layer, and from10.1 to 7.65 GPa for CCML. The hardness was from 0.67 to 0.52 GPa for S2layer, and from 0.65 to 0.52 GPa for CCML. In each test viewpoint place, the average hardness of CCML was almost as high as that of S2layer, but the reduced elastic modulus was about 50% less than that of S2layer. But the increase ratio of mechanical properties was close. All the results showed PF penetrates into the CCML. The penetration behavior and penetration depth from bond line were similar in both S2layer and CCML.

scholarly journals Assessment of the Rheological and Mechanical Properties of Geopolymer Concrete Comprising Fly Ash and Fluid Catalytic Cracking Residue as Aluminosilicate Precursor

2021 ◽  
Vol 11 (7) ◽  
pp. 3032
Author(s):  
Tuan Anh Le ◽  
Sinh Hoang Le ◽  
Thuy Ninh Nguyen ◽  
Khoa Tan Nguyen
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Flexural Strength ◽  
Catalytic Cracking ◽  
Fluid Catalytic Cracking ◽  
High Alumina ◽  
Geopolymer Concrete ◽  
Sem Images

The use of fluid catalytic cracking (FCC) by-products as aluminosilicate precursors in geopolymer binders has attracted significant interest from researchers in recent years owing to their high alumina and silica contents. Introduced in this study is the use of geopolymer concrete comprising FCC residue combined with fly ash as the requisite source of aluminosilicate. Fly ash was replaced with various FCC residue contents ranging from 0–100% by mass of binder. Results from standard testing methods showed that geopolymer concrete rheological properties such as yield stress and plastic viscosity as well as mechanical properties including compressive strength, flexural strength, and elastic modulus were affected significantly by the FCC residue content. With alkali liquid to geopolymer solid ratios (AL:GS) of 0.4 and 0.5, a reduction in compressive and flexural strength was observed in the case of geopolymer concrete with increasing FCC residue content. On the contrary, geopolymer concrete with increasing FCC residue content exhibited improved strength with an AL:GS ratio of 0.65. Relationships enabling estimation of geopolymer elastic modulus based on compressive strength were investigated. Scanning electron microscope (SEM) images and X-ray diffraction (XRD) patterns revealed that the final product from the geopolymerization process consisting of FCC residue was similar to fly ash-based geopolymer concrete. These observations highlight the potential of FCC residue as an aluminosilicate source for geopolymer products.

Sign in / Sign up

Export Citation Format

Share Document