Experimental evidence for ultrafast intermolecular relaxation processes in hydrated biomolecules

2018 ◽  
Vol 14 (10) ◽  
pp. 1062-1066 ◽  
Author(s):  
Xueguang Ren ◽  
Enliang Wang ◽  
Anna D. Skitnevskaya ◽  
Alexander B. Trofimov ◽  
Kirill Gokhberg ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Relaxation Processes ◽  
Intermolecular Relaxation

Vorticity generated by sound

1954 ◽  
Vol 226 (1164) ◽  
pp. 7-16 ◽  
Keyword(s):  
Wind Speed ◽  
Bulk Viscosity ◽  
Viscosity Coefficient ◽  
Order Effects ◽  
Relaxation Processes ◽  
Acoustic Disturbances ◽  
Specific Heats ◽  
Coefficient Of Viscosity ◽  
Bulk Viscosity Coefficient ◽  
Intermolecular Relaxation

A revision is given of the basic theory of second-order effects caused by acoustic disturbances in a fluid, especially the vorticity giving rise to the ultrasonic wind, which was first explained by Eckart. The ultrasonic wind is produced by the interaction of the radiative and the non-radiative components of the acoustic motion. The wind speed is for the most part proportional to the acoustic attenuation coefficient. Wind-speed measurements thus usually furnish no more information about the second coefficient of viscosity, or the bulk viscosity, than do other attenuation measurements. It appears reasonable to regard the Stokesian bulk viscosity coefficient as a parameter of intramolecular and intermolecular relaxation processes. It does not have a unique value for all frequencies. Provided other parameters such as the coefficients of shear viscosity and heat conduction, and the specific heats are known independently, this effective bulk viscosity can be evaluated from any type of attenuation measurement. Measurements over large enough frequency ranges can distinguish among the contributions of different relaxation processes to the effective bulk viscosity coefficient.

scholarly journals Temperature Effects in Rhodamine B Dyes and Improvement in CW Dye Laser Performance

1991 ◽  
Vol 11 (1) ◽  
pp. 31-38 ◽  
Author(s):  
M. A. Ali ◽  
J. Moghaddasi ◽  
S. A. Ahmed
Keyword(s):  
Rhodamine B ◽  
Room Temperature ◽  
Argon Laser ◽  
Dye Laser ◽  
Laser Medium ◽  
Quantum Yields ◽  
Threshold Power ◽  
Relaxation Processes ◽  
Negative Effects ◽  
Intermolecular Relaxation

The effect of cooling the laser medium on the lasing characteristics of an organic cw dye laser, Rhodamine B in ethylene glycol, pumped by an Argon laser was examined. Significant improvements in the performance of this dye laser were achieved as the solvent temperature was reduced below room temperature, namely: a significant reduction in the threshold power requirements and a considerable increase in the attainable output power. The results obtained may be understood in terms of increased quantum yield of the RhB dye as the temperature is reduced. This effect overrides possible negative effects that are normally expected due to intermolecular relaxation processes and which are normally observed for other dye lasers which already have high quantum yields at room temperature.

How do memory modules differentially contribute to familiarity and recollection?

2019 ◽  
Vol 42 ◽  
Author(s):  
Olya Hakobyan ◽  
Sen Cheng
Keyword(s):  
Recognition Memory ◽  
Experimental Evidence ◽  
Subjective Experience ◽  
Target Article ◽  
Memory Modules ◽  
Familiarity And Recollection ◽  
Memory Contents

Abstract We fully support dissociating the subjective experience from the memory contents in recognition memory, as Bastin et al. posit in the target article. However, having two generic memory modules with qualitatively different functions is not mandatory and is in fact inconsistent with experimental evidence. We propose that quantitative differences in the properties of the memory modules can account for the apparent dissociation of recollection and familiarity along anatomical lines.

Redox Reactions in Lipid Membranes as a Model for Primordial Energy-Conserving Systems

1997 ◽  
Vol 161 ◽  
pp. 437-442
Author(s):  
Salvatore Di Bernardo ◽  
Romana Fato ◽  
Giorgio Lenaz
Keyword(s):  
Experimental Evidence ◽  
Lipid Membranes ◽  
Energy Supply ◽  
Redox Reactions ◽  
Living Systems ◽  
Asymmetric Distribution ◽  
Conservation Of Energy ◽  
Asymmetrical Distribution ◽  
Energy Conserving ◽  
Living Organisms

AbstractOne of the peculiar aspects of living systems is the production and conservation of energy. This aspect is provided by specialized organelles, such as the mitochondria and chloroplasts, in developed living organisms. In primordial systems lacking specialized enzymatic complexes the energy supply was probably bound to the generation and maintenance of an asymmetric distribution of charged molecules in compartmentalized systems. On the basis of experimental evidence, we suggest that lipophilic quinones were involved in the generation of this asymmetrical distribution of charges through vectorial redox reactions across lipid membranes.

A Method for Setting the Clearance Angle

1972 ◽  
Vol 30 ◽  
pp. 388-389
Author(s):  
Michael T. Bucek ◽  
Howard J. Arnott
Keyword(s):  
Experimental Evidence ◽  
Light Source ◽  
Black Spot ◽  
Critical Factor ◽  
Clearance Angle ◽  
Crude Approximation ◽  
Ultrathin Sections

It is believed by the authors, with supporting experimental evidence, that as little as 0.5°, or less, knife clearance angle may be a critical factor in obtaining optimum quality ultrathin sections. The degree increments located on the knife holder provides the investigator with only a crude approximation of the angle at which the holder is set. With the increments displayed on the holder one cannot set the clearance angle precisely and reproducibly. The ability to routinely set this angle precisely and without difficulty would obviously be of great assistance to the operator. A device has been contrived to aid the investigator in precisely setting the clearance angle. This device is relatively simple and is easily constructed. It consists of a light source and an optically flat, front surfaced mirror with a minute black spot in the center. The mirror is affixed to the knife by placing it permanently on top of the knife holder.

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