scholarly journals Regeneration of Planarian Auricles and Reestablishment of Chemotactic Ability

2021 ◽  
Vol 9 ◽  
Author(s):  
Eugene Matthew P. Almazan ◽  
Joseph F. Ryan ◽  
Labib Rouhana
Keyword(s):  
Molecular Mechanisms ◽  
Behavioral Experiments ◽  
X Ray ◽  
Preferential Expression ◽  
Chemical Stimuli ◽  
And Function ◽  
Function Models ◽  
Chemotactic Ability

Detection of chemical stimuli is crucial for living systems and also contributes to quality of life in humans. Since loss of olfaction becomes more prevalent with aging, longer life expectancies have fueled interest in understanding the molecular mechanisms behind the development and maintenance of chemical sensing. Planarian flatworms possess an unsurpassed ability for stem cell-driven regeneration that allows them to restore any damaged or removed part of their bodies. This includes anteriorly-positioned lateral flaps known as auricles, which have long been thought to play a central role in chemotaxis. The contribution of auricles to the detection of positive chemical stimuli was tested in this study using Girardia dorotocephala, a North American planarian species known for its morphologically prominent auricles. Behavioral experiments staged under laboratory conditions revealed that removal of auricles by amputation leads to a significant decrease in the ability of planarians to find food. However, full chemotactic capacity is observed as early as 2 days post-amputation, which is days prior from restoration of auricle morphology, but correlative with accumulation of ciliated cells in the position of auricle regeneration. Planarians subjected to x-ray irradiation prior to auricle amputation were unable to restore auricle morphology, but were still able to restore chemotactic capacity. These results indicate that although regeneration of auricle morphology requires stem cells, some restoration of chemotactic ability can still be achieved in the absence of normal auricle morphology, corroborating with the initial observation that chemotactic success is reestablished 2-days post-amputation in our assays. Transcriptome profiles of excised auricles were obtained to facilitate molecular characterization of these structures, as well as the identification of genes that contribute to chemotaxis and auricle development. A significant overlap was found between genes with preferential expression in auricles of G. dorotocephala and genes with reduced expression upon SoxB1 knockdown in Schmidtea mediterranea, suggesting that SoxB1 has a conserved role in regulating auricle development and function. Models that distinguish between possible contributions to chemotactic behavior obtained from cellular composition, as compared to anatomical morphology of the auricles, are discussed.

Characterization of Natural and Synthesized FeTiO3 Crystals With RBS/PIXE/XRD

1997 ◽  
Vol 07 (03n04) ◽  
pp. 265-275
Author(s):  
R. Q. Zhang ◽  
S. Yamamoto ◽  
Z. N. Dai ◽  
K. Narumi ◽  
A. Miyashita ◽  
...  
Keyword(s):  
Single Crystals ◽  
Ion Beam ◽  
Pressure Control ◽  
Floating Zone ◽  
X Ray Diffraction ◽  
X Ray ◽  
Beam Analysis ◽  
Ppm Level

Natural FeTiO 3 (illuminate) and synthesized FeTiO 3, single crystals were characterized by Rutherford backscattering spectroscopy combined with channeling technique and particle-induced x-ray emission (RBS-C and PIXE). The results obtained by the ion beam analysis were supplemented by the x-ray diffraction analysis to identify the crystallographic phase. Oriented single crystals of synthesized FeTiO 3 were grown under the pressure control of CO 2 and H 2 mixture gas using a single-crystal floating zone technique. The crystal quality of synthesized FeTiO 3 single crystals could be improved by the thermal treatment but the exact pressure control is needed to avoid the precipitation of Fe 2 O 3 even during the annealing procedure. Natural FeTiO 3 contains several kinds of impurities such as Mn , Mg , Na and Si . The synthesized samples contain Al , Si and Na which are around 100 ppm level as impurities. The PBS-C results of the natural sample imply that Mn impurities occupy the Fe sublattice in FeTiO 3 or in mixed phase between ilmenite and hematite.

Characterization of WC-Co Coatings Using HP/HVOF Process

1996 ◽  
Author(s):  
S.Y. Hwang ◽  
B.G. Seong ◽  
M.C. Kim
Keyword(s):  
Wear Resistance ◽  
X Ray Diffraction ◽  
High Carbon ◽  
Properties Of Coatings ◽  
X Ray ◽  
Hvof Process ◽  
Number Of Passes ◽  
Oxygen Fuel

Abstract To maintain surface roughness of process rolls in cold rolling steel plants, WC-Co coatings have been known to be effective ones. In this study, a high pressure/high velocity oxygen fuel (HP/HVOF) process was used to obtain WC-Co coatings. To get the best quality of coatings, WC-Co coatings are sprayed with numerous powders made by various processes. These powders include agglomerated sintered powders, fused-crushed powders, extra high carbon WC-Co powders and (W2C, WC)-Co powders. After spraying, properties of coatings such as hardness, wear resistance. X-ray diffraction, and microstructures were analyzed. For coatings produced by agglomerated-sintered powders, hardness of the coating increased as power levels and the number of passes were increased. In case of the coatings produced by fused-crushed powders, a very low deposition rate was obtained due to a low flowablity of the powders. In addition, the WC-Co coatings sprayed with extra carbon content of WC-Co did not show improved hardness and wear resistance. Also, some decomposition of WC was observed in the coating. Finally, the coatings produced by (W2C, WC)-Co powders produced higher hardness and lower wear resistance coating.

scholarly journals Crystallization, optimization and preliminary X-ray characterization of a metal-dependent PI-PLC fromStreptomyces antibioticus

2012 ◽  
Vol 68 (11) ◽  
pp. 1378-1386 ◽  
Author(s):  
Michael R. Jackson ◽  
Thomas L. Selby
Keyword(s):  
X Ray Diffraction ◽  
Hanging Drop ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Streptomyces Antibioticus ◽  
Cell Parameters ◽  
Heavy Atoms ◽  
Hanging Drop Method

A recombinant metal-dependent phosphatidylinositol-specific phospholipase C (PI-PLC) fromStreptomyces antibioticushas been crystallized by the hanging-drop method with and without heavy metals. The native crystals belonged to the orthorhombic space groupP222, with unit-cell parametersa= 41.26,b= 51.86,c = 154.78 Å. The X-ray diffraction results showed significant differences in the crystal quality of samples soaked with heavy atoms. Additionally, drop pinning, which increases the surface area of the drops, was also used to improve crystal growth and quality. The combination of heavy-metal soaks and drop pinning was found to be critical for producing high-quality crystals that diffracted to 1.23 Å resolution.

scholarly journals Evolutionary Conservation of Reactions in Translation

2002 ◽  
Vol 66 (3) ◽  
pp. 460-485 ◽  
Author(s):  
M. Clelia Ganoza ◽  
Michael C. Kiel ◽  
Hiroyuki Aoki
Keyword(s):  
Molecular Mechanisms ◽  
Tertiary Structure ◽  
Evolutionary Conservation ◽  
Initiation Factor ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Common Features ◽  
New Information ◽  
And Function

SUMMARY Current X-ray diffraction and cryoelectron microscopic data of ribosomes of eubacteria have shed considerable light on the molecular mechanisms of translation. Structural studies of the protein factors that activate ribosomes also point to many common features in the primary sequence and tertiary structure of these proteins. The reconstitution of the complex apparatus of translation has also revealed new information important to the mechanisms. Surprisingly, the latter approach has uncovered a number of proteins whose sequence and/or structure and function are conserved in all cells, indicating that the mechanisms are indeed conserved. The possible mechanisms of a new initiation factor and two elongation factors are discussed in this context.

Characterization and Granulometric Correction Soil for the Production of Soil-Cement Blocks for Two Method, Particle Size and X-Ray Florescence to be Inserted in Phase Change Materials (PCMS)

2014 ◽  
Vol 798-799 ◽  
pp. 355-359 ◽  
Author(s):  
Valter Bezerra Dantas ◽  
U.U. Gomes ◽  
A.B. Vital ◽  
G.S. Marinho ◽  
Ariadne de Souza Silva
Keyword(s):  
Particle Size ◽  
Phase Change Materials ◽  
Clay Content ◽  
Particle Size Analysis ◽  
Liquid Limit ◽  
Size Analysis ◽  
X Ray ◽  
Soil Cement

This paper presents the results of tests for characterization of soil samples collected in Mossoró-RN, UFERSA-RN Campus (5 ° 12'34 .68 "South latitude, 37 ° 19 '5.74 "west longitude), for the purpose of producing soil-cement for the manufacture of pressed blocks. Objective of improving the quality of soil-cement, and provide conditions for the use of the soil making it ideal for the production of soil-cement block. Tests of compaction, particle size analysis, plastic limit, liquid limit and correct particle size, X-ray fluorescence and morphology by scanning electron microscopy (SEM). It was concluded that the soil needs correction particle size, due to the high clay content. The method combined grading, sieving, sedimentation and blooming X-ray as the fastest and most accurate in correcting soil particle size.

scholarly journals Growth and Characterization of BxGa1−xN on 6H-SiC (0001) by Movpe

1999 ◽  
Vol 4 (S1) ◽  
pp. 429-434 ◽  
Author(s):  
C. H. Wei ◽  
Z. Y. Xie ◽  
J. H. Edgar ◽  
K. C. Zeng ◽  
J. Y. Lin ◽  
...  
Keyword(s):  
Single Phase ◽  
Band Edge Emission ◽  
Reactant Ratio ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Edge Emission ◽  
X Ray ◽  
Two Phases

Boron was incorporated into GaN in order to determine its limits of solubility, its ability of reducing the lattice constant mismatch with 6H-SiC, as well as its effects on the structural and optical properties of GaN epilayers. BxGa1−xN films were deposited on 6H-SiC (0001) substrates at 950 °C by low pressure MOVPE using diborane, trimethylgallium, and ammonia as precursors. A single phase alloy with x=0.015 was successfully produced at a gas reactant B/Ga ratio of 0.005. Phase separation into pure GaN and BxGa1−xN alloy with x=0.30 was deposited for a B/Ga reactant ratio of 0.01. This is the highest B fraction of the wurtzite structure alloy ever reported. For B/Ga ratio ≥ 0.02, no BxGa1−xN was formed, and the solid solution contained two phases: wurtzite GaN and BN based on the results of Auger and x-ray diffraction. The band edge emission of BxGa1−xN varied from 3.451 eV for x=0 with FWHM of 39.2 meV to 3.465 eV for x=0.015 with FWHM of 35.1 meV. The narrower FWHM indicated that the quality of GaN epilayer was improved with small amount of boron incorporation.

scholarly journals General discussion summary

2002 ◽  
Vol 357 (1426) ◽  
pp. 1419-1420 ◽  
Keyword(s):  
Water Splitting ◽  
Molecular Mechanisms ◽  
Structure And Function ◽  
X Ray ◽  
X Ray Crystallography ◽  
And Function ◽  
Splitting Process

This general discussion was chaired by A. W. Rutherford ( Service de Bioénergétique, Saclay, France ) and revolved around two major topics: (i) the implications of X–ray crystallography on the relationships between structure and function; (ii) the molecular mechanisms of the water–splitting process.

Growth and Characterization of BxGal-xN on 6H-SiC (0001) by MOVPE

1998 ◽  
Vol 537 ◽  
Author(s):  
C. H. Wei ◽  
Z. Y. Xie ◽  
J. H. Edgar ◽  
K. C. Zeng ◽  
J. Y. Lin ◽  
...  
Keyword(s):  
Single Phase ◽  
Band Edge Emission ◽  
Reactant Ratio ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Edge Emission ◽  
X Ray ◽  
Two Phases

AbstractBoron was incorporated into GaN in order to determine its limits of solubility, its ability of reducing the lattice constant mismatch with 6H-SiC, as well as its effects on the structural and optical properties of GaN epilayers. BxGal-xN films were deposited on 6H-SiC (0001) substrates at 950 °C by low pressure MOVPE using diborane, trimethylgallium, and ammonia as precursors. A single phase alloy with x=0.015 was successfully produced at a gas reactant B/Ga ratio of 0.005. Phase separation into pure GaN and BxGal-xN alloy with x=0.30 was deposited for a B/Ga reactant ratio of 0.01. This is the highest B fraction of the wurtzite structure alloy ever reported. For B/Ga ratio ≥ 0.02, no BxGal-xN was formed, and the solid solution contained two phases: wurtzite GaN and BN based on the results of Auger and x-ray diffraction. The band edge emission of BxGal-xN varied from 3.451 eV for x=0 with FWHM of 39.2 meV to 3.465 eV for x=0.015 with FWHM of 35.1 meV. The narrower FWHM indicated that the quality of GaN epilayer was improved with small amount of boron incorporation.

Synthesis and Characterization of Star-Like Copper Oxide (CuO) with Submicrometer Sizes

2012 ◽  
Vol 465 ◽  
pp. 186-191
Author(s):  
Shou Long Gong ◽  
Fang Lin Du
Keyword(s):  
Electron Microscopy ◽  
Synthesis And Characterization ◽  
Simple Liquid ◽  
Liquid Phase Deposition ◽  
Monoclinic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Star-like CuO with submicrometer sizes was fabricated via a simple liquid-phase deposition with the assistant of PVP and Na2MoO4. The as-prepared CuO have been characterized by X-ray diffraction(XRD) and scanning electron microscopy (SEM). The results showed that the as-prepared CuO owned monoclinic structure, the concentrations of PVP, Na2MoO4 and NaOH are very important to the morphology of CuO. The quality of PVP impacts the formation of thin flakes on the skeletons. Meanwhile, the growth of dendritic skeletons was depended on the addition of Na2MoO4, and the effect of NaOH is to control the dimension of CuO structure.

Hydrothermal Synthesis and Structural Characterization of Orthorhombic LiMnO2 with Low Stacking Faults

2015 ◽  
Vol 1120-1121 ◽  
pp. 174-178
Author(s):  
Li Zhu Zhao ◽  
G. Chen
Keyword(s):  
Aqueous Solution ◽  
Structural Characterization ◽  
Stacking Faults ◽  
Lithium Hydroxide ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
Hydrothermal Technique ◽  
X Ray

LiMnO2 are synthesized by hydrothermal technique by using Mn(CH3COO)2.4H2O and MnO2 with the same mole ratio which are dissolved in aqueous solution with different concentration LiOH. Structural characterization based on X-ray diffraction and Raman spectroscopy reveals that LiMnO2 is in a well-order orthorhombic structure with lower stacking faults compared to the LiMnO2 prepared by other techniques. Experimental results show that the concentration of lithium hydroxide in aqueous solution affect the quality of LiMnO2.

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