Analytical modeling provides new insight into complex mutual coupling between surface loops at ultrahigh fields

2017 ◽  
Vol 30 (10) ◽  
pp. e3759 ◽  
Author(s):  
N. I. Avdievich ◽  
A. Pfrommer ◽  
I. A. Giapitzakis ◽  
A. Henning
Keyword(s):  
Mutual Coupling ◽  
Analytical Modeling ◽  
Ultrahigh Fields ◽  
Surface Loops ◽  
Insight Into

scholarly journals Structural Characterization of Cuta- and Tusavirus: Insight into Protoparvoviruses Capsid Morphology

Viruses ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 653
Author(s):  
Mario Mietzsch ◽  
Robert McKenna ◽  
Elina Väisänen ◽  
Jennifer C. Yu ◽  
Maria Ilyas ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Structure Evolution ◽  
Cellular Interactions ◽  
Human Pathogens ◽  
Cryo Electron Microscopy ◽  
Cellular Entry ◽  
Surface Loops ◽  
Antigenic Reactivity ◽  
Insight Into

Several members of the Protoparvovirus genus, capable of infecting humans, have been recently discovered, including cutavirus (CuV) and tusavirus (TuV). To begin the characterization of these viruses, we have used cryo-electron microscopy and image reconstruction to determine their capsid structures to ~2.9 Å resolution, and glycan array and cell-based assays to identify glycans utilized for cellular entry. Structural comparisons show that the CuV and TuV capsids share common features with other parvoviruses, including an eight-stranded anti-parallel β-barrel, depressions at the icosahedral 2-fold and surrounding the 5-fold axes, and a channel at the 5-fold axes. However, the viruses exhibit significant topological differences in their viral protein surface loops. These result in three separated 3-fold protrusions, similar to the bufaviruses also infecting humans, suggesting a host-driven structure evolution. The surface loops contain residues involved in receptor binding, cellular trafficking, and antigenic reactivity in other parvoviruses. In addition, terminal sialic acid was identified as the glycan potentially utilized by both CuV and TuV for cellular entry, with TuV showing additional recognition of poly-sialic acid and sialylated Lewis X (sLeXLeXLeX) motifs reported to be upregulated in neurotropic and cancer cells, respectively. These structures provide a platform for annotating the cellular interactions of these human pathogens.

scholarly journals Unveiling the Hidden Rules of Spherical Viruses Using Point Arrays

Viruses ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 467
Author(s):  
David P. Wilson
Keyword(s):  
Solvent Accessibility ◽  
Geometric Constraints ◽  
Predictive Tool ◽  
Bacteriophage Ms2 ◽  
Lysine Residues ◽  
Critical Insight ◽  
Surface Loops ◽  
Triangulation Number ◽  
Steric Hinderance ◽  
Insight Into

Since its introduction, the Triangulation number has been the most successful and ubiquitous scheme for classifying spherical viruses. However, despite its many successes, it fails to describe the relative angular orientations of proteins, as well as their radial mass distribution within the capsid. It also fails to provide any critical insight into sites of stability, modifications or possible mutations. We show how classifying spherical viruses using icosahedral point arrays, introduced by Keef and Twarock, unveils new geometric rules and constraints for understanding virus stability and key locations for exterior and interior modifications. We present a modified fitness measure which classifies viruses in an unambiguous and rigorous manner, irrespective of local surface chemistry, steric hinderance, solvent accessibility or Triangulation number. We then use these point arrays to explain the immutable surface loops of bacteriophage MS2, the relative reactivity of surface lysine residues in CPMV and the non-quasi-equivalent flexibility of the HBV dimers. We then explain how point arrays can be used as a predictive tool for site-directed modifications of capsids. This success builds on our previous work showing that viruses place their protruding features along the great circles of the asymmetric unit, demonstrating that viruses indeed adhere to these geometric constraints.

Insight into analytical modeling of electromagnetic forming

2018 ◽  
Vol 101 (9-12) ◽  
pp. 2585-2607 ◽  
Author(s):  
Zhipeng Lai ◽  
Quanliang Cao ◽  
Xiaotao Han ◽  
Meng Chen ◽  
Ning Liu ◽  
...  
Keyword(s):  
Analytical Modeling ◽  
Electromagnetic Forming ◽  
Insight Into

scholarly journals Improving Wind Turbine Drivetrain Reliability Using a Combined Experimental, Computational, and Analytical Approach

2014 ◽  
Author(s):  
Yi Guo ◽  
Roger Bergua ◽  
Jeroen van Dam ◽  
Jordi Jove ◽  
Jon Campbell
Keyword(s):  
Wind Turbine ◽  
Analytical Approach ◽  
Analytical Modeling ◽  
Turbine Rotor ◽  
Main Shaft ◽  
Aerodynamic Forces ◽  
Turbine Component ◽  
Bending Loads ◽  
Insight Into ◽  
Wind Turbine Rotor

Nontorque loads induced by the wind turbine rotor overhang weight and aerodynamic forces can greatly affect drivetrain loads and responses. If not addressed properly, these loads can result in a decrease in gearbox component life. This work uses analytical modeling, computational modeling, and experimental data to evaluate a unique drivetrain design that minimizes the effects of nontorque loads on gearbox reliability: the Pure Torque® drivetrain developed by Alstom. The drivetrain has a hub-support configuration that transmits nontorque loads directly into the tower rather than through the gearbox as in other design approaches. An analytical model of Alstom’s Pure Torque drivetrain provides insight into the relationships among turbine component weights, aerodynamic forces, and the resulting drivetrain loads. Main shaft bending loads are orders of magnitude lower than the rated torque and are hardly affected by wind conditions and turbine operations.

scholarly journals Innovative solutions in transformer theory

2021 ◽  
pp. 5-31
Author(s):  
Mansur A. Shakyrov ◽  
◽  
Anton A. Tkachuk ◽  
Keyword(s):  
Energy Transfer ◽  
Magnetic Permeability ◽  
Analytical Modeling ◽  
Poynting Vector ◽  
Practical Importance ◽  
Standard Theory ◽  
Physical Processes ◽  
Innovative Solutions ◽  
Mathematical Equations ◽  
Insight Into

Objective: Clarification of the reasons for errors in the traditional transformer theory and ways of correcting it based on more accurate physical and mathematical equations for describing the pro- cesses of energy transfer in a transformer using the Poynting vector. Demonstrating a new principle of operation and the resulting new properties of the transformer. Methods: The study applies transi- tion from analytical modeling of the device behavior to its equivalent circuit displaying the magnetic fluxes of the transformer. The specific feature of this approach is that at first it is applied to an ideali- zed transformer with infinite magnetic permeability of steel, after which the circuit is built up with elements that take into account saturation and losses in the steel of a real device. Results: The con- tradictions and paradoxes of the standard theory have been revealed. The findings have shown the need to replace it with a doctrine based on equations for real, measurable magnetic fluxes instead of virtual (contrived) fluxes of the official theory. The correctness and significance of the proposed theo- ry is confirmed by the discovery of new properties of transformers and the capability of using it to explain the magnetic overexcitation of individual sections of the transformer in emergency modes. Practical importance: Conditions are provided, and ways are outlined for creating correct textbooks instead of standard ones with outdated ideas about physical processes in transformers. A deeper insight into the operation of transformers resulting from the new theory should contribute to the improvement of methods for increasing their electrodynamic withstand

scholarly journals Unveiling the Hidden Rules of Spherical Viruses Using Point Arrays

2020 ◽  
Author(s):  
David Wilson
Keyword(s):  
Double Point ◽  
Solvent Accessibility ◽  
Geometric Constraints ◽  
Asymmetric Unit ◽  
Local Surface ◽  
Bacteriophage Ms2 ◽  
Surface Loops ◽  
Triangulation Number ◽  
Steric Hinderance ◽  
Insight Into

Since its introduction, the Triangulation number has been the most successful and ubiquitous scheme for classifying spherical viruses. However, despite its many successes, it fails to describe the relative angular orientations of proteins, as well as their radial mass distribution within the capsid. It also fails to provide any insight into critical sites of stability, modifications or possible mutations. We show how classifying spherical viruses using icosahedral point arrays, introduced by Keef and Twarock, unveils new geometric rules and constraints for understanding virus stability and key locations for exterior and interior modifications. We present a modified fitness measure which classifies viruses in an unambiguous and rigorous manner, irrespective of local surface chemistry, steric hinderance, solvent accessibility or triangulation number. We then utilize these point arrays to explain the immutable surface loops of bacteriophage MS2, the relative reactivity of surface lysines in CPMV and the non-quasiequivalent flexibility of the HBV dimers. We explain how using sister and double point arrays can function as predictive tools for site directed modifications in other systems. This success builds on our previous work showing that viruses place their protruding features along the great circles of the asymmetric unit, demonstrating that viruses indeed adhere to these geometric constraints.

Calibration problems in hydrogen luminosities

1966 ◽  
Vol 24 ◽  
pp. 322-330
Author(s):  
A. Beer
Keyword(s):  
Galactic Structure ◽  
B Stars ◽  
Insight Into

The investigations which I should like to summarize in this paper concern recent photo-electric luminosity determinations of O and B stars. Their final aim has been the derivation of new stellar distances, and some insight into certain patterns of galactic structure.

Stochasting modeling of planetary ring systems

1984 ◽  
Vol 75 ◽  
pp. 461-469 ◽  
Author(s):  
Robert W. Hart
Keyword(s):  
Maximum Entropy ◽  
Ring System ◽  
The Sun ◽  
Ultimate State ◽  
Interparticle Interactions ◽  
Ring Systems ◽  
First Order ◽  
Planetary Ring ◽  
Insight Into

ABSTRACTThis paper models maximum entropy configurations of idealized gravitational ring systems. Such configurations are of interest because systems generally evolve toward an ultimate state of maximum randomness. For simplicity, attention is confined to ultimate states for which interparticle interactions are no longer of first order importance. The planets, in their orbits about the sun, are one example of such a ring system. The extent to which the present approximation yields insight into ring systems such as Saturn's is explored briefly.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

Structure and function of neural networks in the retina

1988 ◽  
Vol 46 ◽  
pp. 26-27
Author(s):  
Peter Sterling
Keyword(s):  
Ganglion Cells ◽  
Three Dimensional ◽  
Structure And Function ◽  
Synaptic Connections ◽  
Visual Axis ◽  
One Dimensional ◽  
Cat Retina ◽  
Ultrathin Sections ◽  
And Function ◽  
Insight Into

The synaptic connections in cat retina that link photoreceptors to ganglion cells have been analyzed quantitatively. Our approach has been to prepare serial, ultrathin sections and photograph en montage at low magnification (˜2000X) in the electron microscope. Six series, 100-300 sections long, have been prepared over the last decade. They derive from different cats but always from the same region of retina, about one degree from the center of the visual axis. The material has been analyzed by reconstructing adjacent neurons in each array and then identifying systematically the synaptic connections between arrays. Most reconstructions were done manually by tracing the outlines of processes in successive sections onto acetate sheets aligned on a cartoonist's jig. The tracings were then digitized, stacked by computer, and printed with the hidden lines removed. The results have provided rather than the usual one-dimensional account of pathways, a three-dimensional account of circuits. From this has emerged insight into the functional architecture.

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