scholarly journals Kinetochore-driven outgrowth of microtubules is a central contributor to kinetochore fiber maturation in crane-fly spermatocytes

2014 ◽  
Vol 25 (9) ◽  
pp. 1437-1445 ◽  
Author(s):  
James R. LaFountain ◽  
Rudolf Oldenbourg
Keyword(s):  
Liquid Crystal ◽  
Life Histories ◽  
Polarized Light ◽  
Fiber Formation ◽  
Image Brightness ◽  
Early Stages ◽  
Anaphase Onset ◽  
Bipolar Spindles ◽  
Polarized Light Imaging

We use liquid crystal polarized light imaging to record the life histories of single kinetochore (K-) fibers in living crane-fly spermatocytes, from their origins as nascent K-fibers in early prometaphase to their fully matured form at metaphase, just before anaphase onset. Increased image brightness due to increased retardance reveals where microtubules are added during K-fiber formation. Analysis of experimentally generated bipolar spindles with only one centrosome, as well as of regular, bicentrosomal spindles, reveals that microtubule addition occurs at the kinetochore-proximal ends of K-fibers, and added polymer expands poleward, giving rise to the robust K-fibers of metaphase cells. These results are not compatible with a model for K-fiber formation in which microtubules are added to nascent fibers solely by repetitive “search and capture” of centrosomal microtubule plus ends. Our interpretation is that capture of centrosomal microtubules—when deployed—is limited to early stages in establishment of nascent K-fibers, which then mature through kinetochore-driven outgrowth. When kinetochore capture of centrosomal microtubules is not used, the polar ends of K-fibers grow outward from their kinetochores and usually converge to make a centrosome-free pole.

scholarly journals Design and Realization of a Compact Efficient Beam Combiner, Based on Liquid Crystal Pancharatnam–Berry Phase Gratings

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 220
Author(s):  
Boxuan Gao ◽  
Jeroen Beeckman ◽  
Kristiaan Neyts
Keyword(s):  
Liquid Crystal ◽  
Berry Phase ◽  
Polarized Light ◽  
Laser Beams ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Beam Combiner ◽  
High Diffraction Efficiency ◽  
High Diffraction ◽  
Crystal Mixture

We demonstrate a laser beam combiner based on four photo-patterned Pancharatnam–Berry (PB) phase gratings, which is compact and has high diffraction efficiency for incident circularly polarized light. The nematic liquid crystal mixture E7 is used as anisotropic material, and the thickness of the layer is controlled by spacers. The beam combiner can bring two parallel laser beams closer to each other while remaining parallel. This work shows the potential to realize components based on flat optical LC devices.

Lamellar Lyotropic Liquid Crystal Phases as a Carrier for Skin Delivery of Morus alba Stem Extract

2021 ◽  
Vol 901 ◽  
pp. 67-72
Author(s):  
Chein Yhirayha ◽  
Sakchai Wittaya-Areekul ◽  
Tasana Pitaksuteepong
Keyword(s):  
Liquid Crystal ◽  
Biological Activities ◽  
Polarized Light ◽  
Water Extract ◽  
Skin Penetration ◽  
Morus Alba ◽  
Lyotropic Liquid Crystal ◽  
Mixed Surfactant ◽  
Skin Delivery ◽  
Stem Extract

Morus alba stem extract possesses several biological activities. However, skin delivery of the extract is limited by the stratum corneum. In this study, lamellar lyotropic liquid crystal (LLC) was investigated for the potential application in the skin delivery of M. alba stem extract. The four formulations were developed and incorporated with M. alba stem extract at 3% w/w. These formulations were stored at room temperature in light-protected containers for 3 months. The optical pattern under polarized light microscope, viscosity and remaining of the extract were determined. The skin penetration enhancing property of the formulations was investigated using excised porcine ear skin model. The results showed that all formulations remained stable after 3-month storage. The two formulations exhibiting good penetration enhancing properties were F3 consisting of PEG-7 glyceryl cocoate/n-Dodecane/Water/extract (55.29/19.40/22.31/3.00 %w/w) and F4 consisting of mixed Surfactant/n-Dodecane/Water/extract (48.50/4.85/43.65/3.00 %w/w). The mixed surfactant composed of PEG-7 glyceryl cocoate/PEG-40 hydrogenated castor oil/Glyceryl oleate (40/33.24/26.76 %w/w). It can be concluded that the lamellar LLC formulations developed in this study can be used as a carrier for delivering of M. alba stem extract. The components of the formulations which play important roles are the oil and the surfactant.

Studies on some Sporozoa in Polychaete Worms

Parasitology ◽  
1930 ◽  
Vol 22 (3) ◽  
pp. 370-398 ◽  
Author(s):  
Harendra Nath Ray
Keyword(s):  
Life Histories ◽  
Morphological Characters ◽  
Diagnostic Characters ◽  
Early Stages ◽  
First Time

1. The main facts in Brasil's (1907) account of the intracellular schizogony inSelenidium caulleryifromProtula tubulariahave been confirmed. Early stages in the sporogony of this species are described now for the first time.2. Intracellular schizogony is described for the first time inSelenidium mesniliBrasil fromMyxicola infundibulum, and here also the early stages in sporogony are noted for the first time.3. The life histories of Caullery and Mesnil's two unnamed species ofSelenidium(now calledS. spionis(Köll.) andS. foliatumn.sp.) fromScolelepis fuliginosahave been exhaustively studied. No schizogonic phase has been observed in either. The gametocysts, here described for the first time, are found to develop fully only after escape into the sea. The gametocysts ofS. spionisare ovoid, 108μ x 60μ and contain spores with four sporozoites: those ofS. foliatumare spherical, 70μ in diameter, and their spores contain eight sporozoites.4. New or hitherto little known species ofSelenidiumare recorded fromCirratulus cirratusMüll.,Branchiomma vesiculosumMont.,Sabella pavoninaSav.,Pomatoceros triqueterL. andTerebella lepidoriaKühl, and the morphological characters of the trophozoites are described.5. A discussion follows of the value of the diagnostic characters of the genusSelenidium. It is suggested that this genus requires drastic revision and will probably have to be dismembered. Stress is laid, however, on the occurrence in all the gregarines examined, and at all the observed stages of their development, of characteristic chromatic bodies at the anterior end, structures which have hitherto escaped the notice of most observers.

Quantitative comparison of human myocardial fiber orientations derived from DTI and polarized light imaging

2018 ◽  
Vol 63 (21) ◽  
pp. 215003 ◽  
Author(s):  
Feng Yang ◽  
Yue-Min Zhu ◽  
Gabrielle Michalowicz ◽  
Pierre-Simon Jouk ◽  
Laurent Fanton ◽  
...  
Keyword(s):  
Polarized Light ◽  
Quantitative Comparison ◽  
Myocardial Fiber ◽  
Polarized Light Imaging

scholarly journals Mesomorphism behaviour and photoluminescent properties of new asymmetrical 1,2-di(4-alkoxybenzylidene)hydrazines

2019 ◽  
Vol 43 (1-2) ◽  
pp. 67-77 ◽  
Author(s):  
Adil A Awad ◽  
Al-Ameen Bariz OmarAli ◽  
Ahmed Jasim M Al-Karawi ◽  
Zyad Hussein J Al-Qaisi ◽  
Samer Ghanim Majeed
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Polarized Light ◽  
Luminescent Properties ◽  
Scanning Calorimetry ◽  
Crystalline Materials ◽  
X Ray ◽  
Step Procedure ◽  
Liquid Crystalline Materials

{1-[4-( n-Alkoxy)]-2-(4’-decyloxy)benzylidene}hydrazines ( n-alkoxy = O(CH2) nH, n = 1–9, 12, 16 or 18), an asymmetrical series of 1,2-disubstituted hydrazines, were prepared in a simple two-step procedure as a part of our continuing work in evaluating hydrophobic azine compounds as photoluminescent liquid crystalline materials. The compounds were characterized spectroscopically and their liquid crystalline behaviour and luminescent properties were evaluated using polarized light optical microscopy, differential scanning calorimetry and X-ray powder diffraction techniques. The studies revealed that all of these compounds are liquid crystalline materials exhibiting photoluminescent properties in the crystalline and liquid crystal states.

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