scholarly journals Engineering polar vortex from topologically trivial domain architecture

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Congbing Tan ◽  
Yongqi Dong ◽  
Yuanwei Sun ◽  
Chang Liu ◽  
Pan Chen ◽  
...  
Keyword(s):  
Data Storage ◽  
Domain Architecture ◽  
Vortex Formation ◽  
Three Dimensional ◽  
Polar Vortex ◽  
Dimensional Structure ◽  
Negative Capacitance ◽  
Cross Sectional ◽  
Epitaxial Strain ◽  
Nontrivial Topology

AbstractTopologically nontrivial polar structures are not only attractive for high-density data storage, but also for ultralow power microelectronics thanks to their exotic negative capacitance. The vast majority of polar structures emerging naturally in ferroelectrics, however, are topologically trivial, and there are enormous interests in artificially engineered polar structures possessing nontrivial topology. Here we demonstrate reconstruction of topologically trivial strip-like domain architecture into arrays of polar vortex in (PbTiO3)10/(SrTiO3)10 superlattice, accomplished by fabricating a cross-sectional lamella from the superlattice film. Using a combination of techniques for polarization mapping, atomic imaging, and three-dimensional structure visualization supported by phase field simulations, we reveal that the reconstruction relieves biaxial epitaxial strain in thin film into a uniaxial one in lamella, changing the subtle electrostatic and elastostatic energetics and providing the driving force for the polar vortex formation. The work establishes a realistic strategy for engineering polar topologies in otherwise ordinary ferroelectric superlattices.

Three Dimensional X-Ray Image Synthesis

1972 ◽  
Vol 16 ◽  
pp. 336-343
Author(s):  
David G. Grant
Keyword(s):  
Three Dimensional ◽  
Image Synthesis ◽  
Dimensional Structure ◽  
Cross Sectional ◽  
Projection System ◽  
X Ray ◽  
Optical Projection ◽  
Planar Images ◽  
Scan Length ◽  
Simple Filter

AbstractTomographic systems are able to produce cross sectional planar images of three dimensional volumes because of the relative motion of the source, film and the volume under examination. Analysis shows that the image produced is a result of a three dimensional linear filtering process where the filter characteristics are determined by the scan geometry (3). If, instead of integrating continuously on a single film, a set of N radiographs are recorded, each corresponding to a point along the scan trajectory, then a simple filter can be defined to reconstruct the entire three dimensional structure from this data. In this case, the transfer function exhibits repetitive peaks whose spacing is determined by N and whose width is determined by the total scan length. The number of views required to produce the same “blurring” as the continuous case can then be determined by the Nyquist criteria(3).An optical projection system based on circular geometry for producing three dimensional medical images has been fabricated and tested. The technique can be generalized to any geometry and to all x-ray applications where plane-by-plane examination of a structure would prove beneficial.

scholarly journals Structural analysis of tRNA(His) guanylyltransferase comlexed with tRNA

2014 ◽  
Vol 70 (a1) ◽  
pp. C1816-C1816
Author(s):  
Akiyoshi Nakamura ◽  
Taiki Nemoto ◽  
Isao Tanaka ◽  
Min Yao
Keyword(s):  
Crystal Structures ◽  
Domain Architecture ◽  
Gel Filtration ◽  
Three Dimensional ◽  
Trna Synthetase ◽  
Dimensional Structure ◽  
Catalytic Core ◽  
X Ray ◽  
Catalytic Activation ◽  
X Ray Scattering

tRNA(His) guanylyltransferase (Thg1) of eukaryote adds a guanylate to the 5' end of immature or incorrectly processed tRNAs (3'-5' polymerization) by three reaction steps: adenylylation; guanylylation and dephosphorylation. This additional guanylate provides the major identity element for histidyl-tRNA synthetase to recognize its cognate substrate tRNA(His) and differentiates tRNA(His) from the pool of tRNAs present in the cell (1). Previous studies indicate that Thg1 is a structural homolog of canonical 5'-3' polymerases in the catalytic core with no obvious conservation of the amino acid sequence(2). However, the substrate binding of Thg1 is unclear and requires information on the three-dimensional structure in complex with tRNA. In this study, we determined the crystal structures of Thg1 from Candida albicans (CaThg1) in tRNA-bound (CaThg1-tRNA), ATP-bound (CaThg1-ATP), and GTP-bound (CaThg1-GTP) form, and elucidated how Thg1 functions as a reverse polymerase to add nucleotide(3). The crystal structures of CaThg1-tRNA complex shows that two tRNAs are bound to tetrameric Thg1 in parallel orientation which is consistent with SAXS (Small angle X-ray scattering) and gel filtration analysis. One tRNA interacts with three monomers for its positioning, anticodon recognition, and catalytic activation. The end of the acceptor stem and the anticodon loop are both recognized by the same sub-domain belonging to the different monomers. Moreover, the structural comparison of Thg1-tRNA with canonical 5'-3' polymerase shows that the domain architecture of Thg1 is reversed to that of canonical 5'-3' polymerase.

scholarly journals Questing functions and structures of hypothetical proteins from Campylobacter jejuni: a computer-aided approach

2020 ◽  
Vol 40 (6) ◽  
Author(s):  
Md. Amran Gazi ◽  
Sultan Mahmud ◽  
Shah Mohammad Fahim ◽  
Md. Rezaul Islam ◽  
Subhasish Das ◽  
...  
Keyword(s):  
Campylobacter Jejuni ◽  
Protein Interactions ◽  
In Silico ◽  
Domain Architecture ◽  
Three Dimensional ◽  
Physicochemical Characterization ◽  
Dimensional Structure ◽  
Hypothetical Proteins ◽  
Roc Curve Analysis ◽  
Full Spectrum

Abstract Campylobacter jejuni (C. jejuni) is considered to be one of the most frequent causes of bacterial gastroenteritis globally, especially in young children. The genome of C. jejuni contains many proteins with unknown functions termed as hypothetical proteins (HPs). These proteins might have essential biological role to show the full spectrum of this bacterium. Hence, our study aimed to determine the functions of HPs, pertaining to the genome of C. jejuni. An in-silico work flow integrating various tools were performed for functional assignment, three-dimensional structure determination, domain architecture predictors, subcellular localization, physicochemical characterization, and protein–protein interactions (PPIs). Sequences of 267 HPs of C. jejuni were analyzed and successfully attributed the function of 49 HPs with higher confidence. Here, we found proteins with enzymatic activity, transporters, binding and regulatory proteins as well as proteins with biotechnological interest. Assessment of the performance of various tools used in this analysis revealed an accuracy of 95% using receiver operating characteristic (ROC) curve analysis. Functional and structural predictions and the results from ROC analyses provided the validity of in-silico tools used in the present study. The approach used for this analysis leads us to assign the function of unknown proteins and relate them with the functions that have already been described in previous literature.

Development and Validation of the Nurse Prescribing Self-Efficacy Scale

2020 ◽  
pp. 019394592096250
Author(s):  
Teresa Galiana-Camacho ◽  
María Dolores Ruiz-Fernandez ◽  
Iria Dobarrio-Sanz ◽  
José Granero-Molina ◽  
Cayetano Fernandez-Sola ◽  
...  
Keyword(s):  
Internal Consistency ◽  
Content Validity ◽  
Self Efficacy ◽  
Intraclass Correlation ◽  
Temporal Stability ◽  
Three Dimensional ◽  
Cross Sectional Study ◽  
Dimensional Structure ◽  
Cross Sectional ◽  
Nurse Prescribing

Low self-efficacy is a barrier to effective nurse prescribing. Therefore, nurses’ self-efficacy should be assessed using validated tools. We aimed to develop and psychometrically test the Nurse Prescribing Self-Efficacy Scale (NP-SES). We conducted an observational cross-sectional study with 290 nurses between January and June 2019. We studied the NP-SES’ reliability (i.e., internal consistency and temporal stability), validity (i.e., content, criterion, and construct) and legibility. The NP-SES showed good internal consistency (Cronbach’s alpha=0.958) and temporal stability (intraclass correlation coefficient=0.783). The NP-SES also showed good content validity (scale’s content validity index=0.98) and criterion validity ( r=0.75; p<0.001). Construct validity analysis revealed the NP-SES’ three-dimensional structure and showed its ability to detect significant differences between nurses with different levels of experience. Our psychometric analysis suggests that the NP-SES is a reliable and valid instrument that could be used to assess nurses’ self-efficacy in nurse prescribing.

Cross-sectional features and three-dimensional structure of human placental Villi

Placenta ◽  
1987 ◽  
Vol 8 (3) ◽  
pp. 235-247 ◽  
Author(s):  
Peter Kaufmann ◽  
Michael Luckhardt ◽  
Gertfried Schweikhart ◽  
Steven John Cantle
Keyword(s):  
Three Dimensional ◽  
Dimensional Structure ◽  
Cross Sectional ◽  
Three Dimensional Structure ◽  
Placental Villi

scholarly journals Luminal particles within cellular microtubules

2006 ◽  
Vol 174 (6) ◽  
pp. 759-765 ◽  
Author(s):  
Boyan K. Garvalov ◽  
Benoît Zuber ◽  
Cédric Bouchet-Marquis ◽  
Mikhail Kudryashev ◽  
Manuela Gruska ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Cross Sectional ◽  
Microtubule Associated Proteins ◽  
Associated Proteins ◽  
Quantitative Manner ◽  
Internal Side ◽  
20 Nm ◽  
Cellular Components

The regulation of microtubule dynamics is attributed to microtubule-associated proteins that bind to the microtubule outer surface, but little is known about cellular components that may associate with the internal side of microtubules. We used cryoelectron tomography to investigate in a quantitative manner the three dimensional structure of microtubules in intact mammalian cells. We show that the lumen of microtubules in this native state is filled with discrete, globular particles with a diameter of 7 nm and spacings between 8 and 20 nm in neuronal cells. Cross-sectional views of microtubules confirm the presence of luminal material in vitreous sections of brain tissue. Most of the luminal particles had connections to the microtubule wall, as revealed in tomograms. A higher accumulation of particles was seen near the retracting plus ends of microtubules. The luminal particles were abundant in neurons, but were also observed in other cells, such as astrocytes and stem cells.

Sectioning Clay Models Makes Anatomy & Development Tangible

2010 ◽  
Vol 72 (5) ◽  
pp. 313-314 ◽  
Author(s):  
Carina Endres Howell ◽  
James Endres Howell
Keyword(s):  
Embryonic Development ◽  
Cross Sections ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Dimensional Structure ◽  
Cross Sectional ◽  
Three Dimensional Structure ◽  
Teaching Aids

Clay models have proved to be useful teaching aids for many topics in biology that depend on three-dimensional reasoning. Students studying embryonic development struggle to mentally reconstruct the three-dimensional structure of embryos and larvae by observing prepared slides of cross-sectional slices. Students who build clay models of embryos and slice them into cross sections, however, have a much easier time interpreting the slices of real embryos and gain a deeper understanding of development in three dimensions.

scholarly journals Automated S/TEM Sample Preparation for Semiconductor Process Support

2007 ◽  
Vol 15 (1) ◽  
pp. 26-29
Author(s):  
Greg Cuti ◽  
Taha Jabbar
Keyword(s):  
Semiconductor Industry ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Cross Sectional ◽  
Critical Dimensions ◽  
Manufacturing Operations ◽  
Process Support ◽  
Scanning Transmission ◽  
Cross Sectional Imaging ◽  
20 Nm

The semiconductor industry has unquestionably entered the realm of nanotechnology. Critical dimensions of many features are specified in nanometers. Gate oxides are only a few nanometers thick. Barrier and seed layers for copper processes are not much more. Gate lengths are forecast at less than 20 nm by the end of the decade. Additionally, the drive to increase device density is leading to the adoption of FinFET and other new transistor designs that include complex three-dimensional structure. Even conventional planar CMOS designs now incorporate processes such as damascene interconnects that are inherently three dimensional. The combined need for higher spatial resolution and cross-sectional imaging of complex structures has led to a significant increase in the demand for scanning transmission electron microscopy (STEM) and (TEM) in semiconductor manufacturing operations.

Three dimensional structure and fluid flow through the hydrospires of the blastoid echinoderm, Pentremites rusticus

2010 ◽  
Vol 84 (1) ◽  
pp. 109-117 ◽  
Author(s):  
Ronald C. Schmidtling ◽  
Charles R. Marshall
Keyword(s):  
Fluid Flow ◽  
Digital Image ◽  
Full Range ◽  
Three Dimensional ◽  
Initial Study ◽  
Dimensional Structure ◽  
Cross Sectional ◽  
Form And Function ◽  
Flow Through ◽  
And Function

The fluid flow through the complex hydrospires of the spiraculate blastoid Pentremites rusticus was analyzed using the first high-resolution three-dimensional digital image (and animation) of the hydrospires taken from a serially sectioned specimen. Measurements of the cross-sectional areas within the hydrospires, in conjunction with the Principle of Continuity, were used to infer the relative water velocity throughout the structures. Even though the calyx narrows adorally, the hydrospires expand in size, keeping pace with the increasing volume of water that entered through the hydrospire pores. Thus, the water maintained a relatively constant velocity within the hydrospire canals, 3.4 to 4.5 times the incurrent velocity. The spiracular openings are sufficiently large that no substantial increase in the exit velocity of the seawater would have been achieved unless the spiracular cover plates were used to reduce the size of the spiracular openings, which we infer was probably the case. The three-dimensional images underscore the fact that the two hydrospires that lie under each ambulacrum do not share the same spiracle and are not connected. Thus, we here redefine the term “hydrospire set” to refer to the pair of hydrospires that are connected. A number of anomalous accessory pores and canals were identified in the digital images. This initial study is based on a single specimen, and thus we were unable to determine the full range of variation present in Pentremites rusticus. Nonetheless, the digital image and the application of the Principle of Continuity offer new insights into the form and function of these remarkable respiratory structures.

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

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