Transparent Cell

2011 ◽  
pp. 229-248
Keyword(s):  
Transparent Cell

scholarly journals AN IMPROVED AIR-DRIVEN TYPE OF ULTRACENTRIFUGE FOR MOLECULAR SEDIMENTATION

1937 ◽  
Vol 65 (4) ◽  
pp. 565-586 ◽  
Author(s):  
Johannes H. Bauer ◽  
Edward G. Pickels
Keyword(s):  
High Speed ◽  
Optical Systems ◽  
Centrifugal Field ◽  
Braking System ◽  
Axis Of Rotation ◽  
Protein Molecules ◽  
Transparent Cell ◽  
Definition Of ◽  
Operation Characteristics

1. A description is given of the construction details and operation characteristics of an improved type of air-driven ultracentrifuge operating in vacuum and suitable for the determination of sedimentation constants of protein molecules. 2. The rotor of the centrifuge is made of a forged aluminum alloy; it is oval in shape, measures 185 mm. at its greatest diameter, and weighs 3,430 gm. It carries a transparent cell located at a distance of 65 mm. from the axis of rotation and designed to accommodate a fluid column 15 mm. high. 3. The rotor has been run repeatedly over long periods at a speed of 60,000 R.P.M., which corresponds to a centrifugal force of 260,000 times gravity in the center of the cell. At this speed no deformation of the rotor nor leakage of the cell has been observed. 4. The sharp definition of sedimentation photographs taken at high speed serves to indicate the absence of detectable vibrations in the centrifuge. 5. When a vacuum of less than 1 micron of mercury is maintained in the centrifuge chamber, the rise in the rotor temperature amounts to only 1 or 2°C. after several hours' run at high speed. 6. There has been no evidence of convection currents interfering with normal sedimentation of protein molecules in the centrifugal field. 7. A driving air pressure of about 18 pounds per square inch is sufficient to maintain the centrifuge at a steady speed of 60,000 R.P.M. With a driving pressure of 80 pounds per square inch, it can be accelerated to this speed in less than 20 minutes, and also brought to rest in about the same length of time by the application of the braking system. 8. The adaptation of Svedberg's optical systems to this centrifuge for photographically recording the movement of sedimentation boundaries is described.

scholarly journals The Effect of Polarized Light on the Growth of a Transparent Cell

1960 ◽  
Vol 43 (5) ◽  
pp. 897-909 ◽  
Author(s):  
L. F. Jaffe
Keyword(s):  
Growth Response ◽  
Alternative Explanation ◽  
Polarized Light ◽  
Radial Position ◽  
Infinite Cylinder ◽  
Homogeneous Sphere ◽  
Surface Reflection ◽  
Transparent Cell ◽  
Coaxial Shell

It is shown that light lost by reflection before entering a clear and homogeneous sphere or infinite cylinder is precisely compensated by light retained within these bodies by internal reflection; compensation means that the total rate of light absorption by infinitely dilute photoreceptors as integrated through the whole of these bodies or even through any concentric or coaxial shell making them up is independent of surface reflection. In the Phycomyces sporangiophore this theorem precludes a reflection explanation of R, the polarization dependence of the light growth response. An alternative explanation based upon anisotropic absorption by the receptors is explored and found tenable. Formulae are derived for R in any transparent cylindrical cell as a function of the constants of anisotropic absorption by the photoreceptors taken as a group (CH' and CL'), of the radial position of the receptors, and of the refractive indices of the cell (n) and of the medium (N). It is inferred that the photoreceptors in the Phycomyces sporangiophore are most absorbent for light vibrating in the direction of a hoop around a barrel. Orientation of the receptors by linkage to the cell wall is then shown to be a plausible explanation of the inferred anisotropy. On the basis of anisotropic reception, it is predicted that R should be constant for any N > n, and it is shown how CH', C,L' and the radial position of the receptors may all be obtained from a careful determination of R as a function of N.

Aquimonospora tratensis gen. et sp. nov. (Diaporthomycetidae, Sordariomycetes), a new lineage from a freshwater habitat in Thailand

Phytotaxa ◽  
2019 ◽  
Vol 397 (2) ◽  
pp. 146 ◽  
Author(s):  
JING YANG ◽  
JIAN-KUI (JACK) LIU ◽  
KEVIN D. HYDE ◽  
E.B. GARETH JONES ◽  
ZONG-LONG LUO ◽  
...  
Keyword(s):  
New Genus ◽  
Unique Feature ◽  
Sequence Data ◽  
Phylogenetic Analyses ◽  
New Taxon ◽  
The Novel ◽  
Lower Semi ◽  
The Family ◽  
Freshwater Stream ◽  
Transparent Cell

An interesting hyphomycetous taxon was collected on submerged wood in a freshwater stream in Trat Province, Thailand. It is morphologically similar to endophragmiella-like taxa, characterized by macronematous, mononematous conidiophores, monoblastic, enteroblastic conidiogenous cells and clavate to obovoid, septate brown conidia. The unique feature of this taxon is that the mature conidium often bears a young new conidial primordium which develops percurrently from a lower semi-transparent cell and they secede simultaneously. Phylogenetic analyses of a combined LSU, SSU and RPB2 sequence data support the placement of this fungus together with Platytrachelon and close to the family Papulosaceae within Diaporthomycetidae, Sordariomycetes. A new genus is introduced to accommodate the new taxon as Aquimonospora. The novel species Aquimonospora tratensis is described and illustrated and is compared with other morphologically similar taxa.

scholarly journals A transparent cell-culture microchamber with a variably controlled concentration gradient generator and flow field rectifier

2008 ◽  
Vol 2 (2) ◽  
pp. 024105 ◽  
Author(s):  
Ji-Yen Cheng ◽  
Meng-Hua Yen ◽  
Ching-Te Kuo ◽  
Tai-Horng Young
Keyword(s):  
Cell Culture ◽  
Flow Field ◽  
Concentration Gradient ◽  
Gradient Generator ◽  
Transparent Cell
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