scholarly journals Seventeen-Armed Star Polystyrenes in Various Molecular Weights: Structural Details and Chain Characteristics

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1894
Author(s):  
Jia Chyi Wong ◽  
Li Xiang ◽  
Kuan Hoon Ngoi ◽  
Chin Hua Chia ◽  
Kyeong Sik Jin ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Star Polymers ◽  
Star Polymer ◽  
Dimensional Structure ◽  
Density Profiles ◽  
Molecular Weights ◽  
Radiation Sources ◽  
Structural Details

Star-shaped polymers are very attractive because of their potential application ability in various technological areas due to their unique molecular topology. Thus, information on the molecular structure and chain characteristics of star polymers is essential for gaining insights into their properties and finding better applications. In this study, we report molecular structure details and chain characteristics of 17-armed polystyrenes in various molecular weights: 17-Arm(2k)-PS, 17-Arm(6k)-PS, 17-Arm(10k)-PS, and 17-Arm(20k)-PS. Quantitative X-ray scattering analysis using synchrotron radiation sources was conducted for this series of star polymers in two different solvents (cyclohexane and tetrahydrofuran), providing a comprehensive set of three-dimensional structure parameters, including radial density profiles and chain characteristics. Some of the structural parameters were crosschecked by qualitative scattering analysis and dynamic light scattering. They all were found to have ellipsoidal shapes consisting of a core and a fuzzy shell; such ellipse nature is originated from the dendritic core. In particular, the fraction of the fuzzy shell part enabling to store desired chemicals or agents was confirmed to be exceptionally high in cyclohexane, ranging from 74 to 81%; higher-molecular-weight star polymer gives a larger fraction of the fuzzy shell. The largest fraction (81%) of the fuzzy shell was significantly reduced to 52% in tetrahydrofuran; in contrast, the lowest fraction (19%) of core was increased to 48%. These selective shell contraction and core expansion can be useful as a key mechanism in various applications. Overall, the 17-armed polystyrenes of this study are suitable for applications in various technological fields including smart deliveries of drugs, genes, biomedical imaging agents, and other desired chemicals.

scholarly journals Brain capillary structures of schizophrenia cases and controls show a correlation with their neuron structures

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rino Saiga ◽  
Masayuki Uesugi ◽  
Akihisa Takeuchi ◽  
Kentaro Uesugi ◽  
Yoshio Suzuki ◽  
...  
Keyword(s):  
Blood Vessels ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Superior Temporal Gyrus ◽  
Anterior Cingulate ◽  
Dimensional Structure ◽  
Constant Diameter ◽  
The Mean ◽  
Cartesian Coordinate ◽  
Micrometer Scale

AbstractBrain blood vessels constitute a micrometer-scale vascular network responsible for supply of oxygen and nutrition. In this study, we analyzed cerebral tissues of the anterior cingulate cortex and superior temporal gyrus of schizophrenia cases and age/gender-matched controls by using synchrotron radiation microtomography or micro-CT in order to examine the three-dimensional structure of cerebral vessels. Over 1 m of cerebral blood vessels was traced to build Cartesian-coordinate models, which were then used for calculating structural parameters including the diameter and curvature of the vessels. The distribution of vessel outer diameters showed a peak at 7–9 μm, corresponding to the diameter of the capillaries. Mean curvatures of the capillary vessels showed a significant correlation to the mean curvatures of neurites, while the mean capillary diameter was almost constant, independent of the cases. Our previous studies indicated that the neurites of schizophrenia cases are thin and tortuous compared to controls. The curved capillaries with a constant diameter should occupy a nearly constant volume, while neurons suffering from neurite thinning should have reduced volumes, resulting in a volumetric imbalance between the neurons and the vessels. We suggest that the observed structural correlation between neurons and blood vessels is related to neurovascular abnormalities in schizophrenia.

Structural modeling and role of HAX-1 as a positive allosteric modulator of human serine protease HtrA2

2019 ◽  
Vol 476 (20) ◽  
pp. 2965-2980
Author(s):  
Lalith K. Chaganti ◽  
Shubhankar Dutta ◽  
Raja Reddy Kuppili ◽  
Mriganka Mandal ◽  
Kakoli Bose
Keyword(s):  
Pdz Domain ◽  
Limited Proteolysis ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Multifunctional Protein ◽  
Promising Therapeutic Target ◽  
Wide Range ◽  
Structural Details ◽  
Structural Architecture ◽  
First Time

Abstract HAX-1, a multifunctional protein involved in cell proliferation, calcium homeostasis, and regulation of apoptosis, is a promising therapeutic target. It regulates apoptosis through multiple pathways, understanding of which is limited by the obscurity of its structural details and its intricate interaction with its cellular partners. Therefore, using computational modeling, biochemical, functional enzymology and spectroscopic tools, we predicted the structure of HAX-1 as well as delineated its interaction with one of it pro-apoptotic partner, HtrA2. In this study, three-dimensional structure of HAX-1 was predicted by threading and ab initio tools that were validated using limited proteolysis and fluorescence quenching studies. Our pull-down studies distinctly demonstrate that the interaction of HtrA2 with HAX-1 is directly through its protease domain and not via the conventional PDZ domain. Enzymology studies further depicted that HAX-1 acts as an allosteric activator of HtrA2. This ‘allosteric regulation’ offers promising opportunities for the specific control and functional modulation of a wide range of biological processes associated with HtrA2. Hence, this study for the first time dissects the structural architecture of HAX-1 and elucidates its role in PDZ-independent activation of HtrA2.

scholarly journals Report on the Real Structure of Benzene Molecules and the Thickness of Graphene

2021 ◽  
Author(s):  
Ning Wang ◽  
Dulun Wang
Keyword(s):  
Molecular Structure ◽  
Layer Structure ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Quantum Mechanical ◽  
Ultraviolet Spectroscopy ◽  
Quantum Mechanical Calculations ◽  
Covalent Bonds ◽  
Wide Range ◽  
Long Time

Abstract The problem of the benzene molecular structure has not been solved for a long time. This research proposes a new concept of covalent bonds based on the existing theory: each electron shared by the nucleus corresponds to a half-valent bond, and a half-valent bond can be formed between interval carbon atoms of the benzene ring. A new theory was established. Quantum mechanical calculations results can quantitatively explain experimental results, such as the hydrogenation heat and ultraviolet spectroscopy of benzene. It has solved more than one hundred years of difficult problems. The design of the new structural forms of benzene molecules shows half-valent bonds with dotted lines, which have a wide range of adaptability, and shows the structural forms and reaction formulas of more than dozens of benzene homologs and derivatives. Under the guidance of the new theory, the stacked three-dimensional structure of benzene was explored. The thickness of the three-layer benzene tube is calculated to be almost equal to the thickness of the graphene. Therefore, it is speculated that graphene may be a three layer structure.

Yhe Compression Meso-Mechanics Theoretical Model and Experimental Verification of Polyurethane-Based Warp-Knit Spacer Fabric Composites

2021 ◽  
Vol 8 (5) ◽  
pp. 30-38
Author(s):  
Si Chen
Keyword(s):  
Theoretical Model ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Beam Theory ◽  
Theoretical Research ◽  
Dimensional Structure ◽  
Static Compression ◽  
Theoretical Simulation ◽  
Winkler Elastic Foundation ◽  
Spacer Fabric

In this research, a new type of binary material, a polyurethane-based warp-knitted spacer fabric composite (PWSF), having a unique three-dimensional structure, high strength, and a variety of surface structures was prepared. The compression meso-mechanics theoretical model based on the Winkler elastic foundation beam theory and structural parameters of PWSF were used to predict the compression performance of PWSF. To verify the validity of compression model, the compression stress-strain curves of theoretical simulation were compared with the quasi-static compression test results. The deviation between these two compression moduli was less than 7%. The compression meso-mechanics model established in this study can effectively simulate the actual compression behaviors for different PWSF specimens. A regular pattern of compression properties of this novel composite from the theoretical research on meso-mechanics perspectives can be proposed.

scholarly journals Crystal structure of 2-[(1R,2R,4aS,8aS)-2-hydroxy-2,5,5,8a-tetramethyldecahydronaphthalen-1-yl]-N-(o-tolyl)acetamide

2015 ◽  
Vol 71 (10) ◽  
pp. o788-o789
Author(s):  
Dang-Dang Li ◽  
Xin-Wei Shi ◽  
Qiang-Qiang Lu ◽  
Sheng-Kun Li
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Compound C ◽  
Amide Derivative ◽  
Ring Motif

The title compound, C23H35NO2, is an amide derivative of the lactone (+)-sclareolide, and was synthesized from natural sclareol. In the molecular structure, the two six-membered rings (AandB) of the labdane skeleton aretrans-fused, and adopt chair conformations. There is an intramolecular N—H...O hydrogen bond present forming anS(7) ring motif. In the crystal, O—H...O hydrogen bonds link the molecules into helical chains propagating along theb-axis direction. The chains are linkedviaC—H...π interactions, forming a three-dimensional structure.

Three-Dimensional Structure Trajectory Guiding Scan and Points Cloud Registration

2013 ◽  
Vol 300-301 ◽  
pp. 423-426
Author(s):  
Yong Cai
Keyword(s):  
Point Cloud ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Surface Model ◽  
Visual Measurement ◽  
Local Point ◽  
Inverse Kinematics Problem ◽  
The Relationship ◽  
Measurement Approach

Three-dimensional visual scanning is an advanced non-contact measurement approach that can obtain a complete surface model of object. But, in the method, the local raster point cloud sets calculated must be registered to a whole. To reduce fluctuating errors and increase efficiency, we propose a new method that scanner can be moved around object guided by pre-planning trajectory of the robot. First, considering the structural parameters of the robot, the Inverse Kinematics Problem of each joint rotating function is derived, and the moving trajectory is simulated. Then, the relationship between the distances of controlled motion and data gotten by scanner is analyzed, a transform matrix which registered the local point cloud sets is deduced, the raster data can be normalized to the world coordinate by it. The experimental results show that error of registration is less than 0.09mm. The method is suited to measuring different targets in robot workspace. It can improve the efficiency and flexibility of visual measurement system.

Correlation of shearing properties with the structure of garment leathers

1990 ◽  
Vol 48 (4) ◽  
pp. 838-839
Author(s):  
B. Lokanadam ◽  
V. Subramaniam ◽  
T. Ramasami
Keyword(s):  
Three Dimensional ◽  
Dimensional Structure ◽  
Stress And Strain ◽  
Radial Deformation ◽  
Intrinsic Properties ◽  
Textile Fabrics ◽  
Structural Details ◽  
Simple Instrument ◽  
Shear Stress And Strain ◽  
Shape Retention

Shearing property is of fundamental importance in influencing the complex deformations of a garment leather during use. The properties such as stretch, shape retention etc., are closely related to the shearing behaviour of garment leather. Although, textile fabrics have been investigated extensively for their shearing properties(1-3), the studies on leather have been limited. It is logical to expect the three-dimensional structure of leather and the intrinsic properties of collagenous fibre would be markedly different from those of other textile fabrics. The shearing property of a fabric can be expected to be influenced by its weave and matrix structure. An attempt has now been made to correlate the ultra and micro structural details of a garment leather with its shearing properties.A simple instrument has now been developed to assess the shearing behaviour of a soft fabric like garment leather. The shear test on garment leather involves the radial deformation of a sample piece by small degrees and measurement of the resultant shear stress and strain levels. Full chrome grain garment and suede garment leathers obtained from sheep skins were used for measurement of shearing properties.

scholarly journals Splayed Tetrahymena cilia. A system for analyzing sliding and axonemal spoke arrangements.

1976 ◽  
Vol 71 (2) ◽  
pp. 589-605 ◽  
Author(s):  
W S Sale ◽  
P Satir
Keyword(s):  
Structural Parameters ◽  
Three Dimensional ◽  
Tetrahymena Pyriformis ◽  
Dimensional Structure ◽  
Ciliary Movement ◽  
Dimensional Changes ◽  
Local Contraction ◽  
Critical Point Drying ◽  
Triton X ◽  
Section Analysis

This study makes use of a procedure designed to illustrate, without serial section analysis, the three-dimensional changes in the ciliary axoneme produced by microtubule sliding, and to confirm essential features of the sliding microtubule hypothesis of ciliary movement. Cilia, isolated from Tetrahymena pyriformis by the dibucaine procedure, are attached to polylysine substratum, and treated with Triton X-100. Critical point drying maintains three-dimensional structure without embedding. The detergent removes the membrane and many axonemes unroll, always in an organized fashion so that doublets follow one another in sequence, according to the enantiomorphic form of the cilium. The central pair of microtubules fall to the side as a unit. The parallel doublet microtubules retain relative longitudinal positions in part by interdoublet or nexin links. Spoke organization and tip patterns are preserved in the opened axonemes. We generalize the work of Warner and Satir (Warner, F. D., and P. Satir, 1976. J. Cell Biol. 63:35-63) to show that spoke group arrangements are maintained for all doublets in straight regions, while systematic displacements occur in bent regions. The conclusion that local contraction of microtubles is absent in the axoneme is strengthened, and direct graphic demonstrations of sliding at the ciliary tip are shown. A morphogenetic numbering scheme is presented which results in a quantitative fit of the tip images to the images predicated by the equation for doublet sliding, and which makes possible new comparisons of structural parameters between axonemes and with cilia of other organisms.

scholarly journals Crystal structure of 2-[(3S,4S)-4-(anthracen-9-yl)-1-(4-methoxyphenyl)-2-oxoazetidin-3-yl]-2-aza-2H-phenalene-1,3-dione unknown solvate

2015 ◽  
Vol 71 (3) ◽  
pp. o184-o185 ◽  
Author(s):  
Ísmail Çelik ◽  
Mehmet Akkurt ◽  
Aliasghar Jarrahpour ◽  
Javad Ameri Rad ◽  
Ömer Çelik
Keyword(s):  
Molecular Structure ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Dihedral Angles ◽  
Maximum Deviation ◽  
Stacking Interactions ◽  
Acta Cryst ◽  
Compound C ◽  
Lactam Ring ◽  
Solvent Molecules

The central β-lactam ring of the title compound, C36H24N2O4, is almost planar (r.m.s. deviation = 0.003 Å) and makes dihedral angles of 17.17 (19), 89.76 (17) and 78.44 (17)° with the benzene ring, the anthracene ring (r.m.s. deviation = 0.003 Å) and the 1H-benzo[de]isoquinoline-1,3(2H)-dione moiety, which is nearly planar [maximum deviation = 0.098 (2) Å], respectively. The molecular structure is stabilized by an intramolecular C—H...N hydrogen bond. In the crystal, molecules are linkedviaC—H...π and π–π stacking interactions [centroid–centroid distances = 3.5270 (19) and 3.779 (2) Å], forming a three-dimensional structure. A region of disordered electron density, probably disordered solvent molecules, was treated with the SQUEEZE procedure inPLATON[Spek (2015).Acta Cryst.C71, 9–18], which indicated a solvent cavity of 322 Å3containing approximately 91 electrons. Their formula mass and unit-cell characteristics were not taken into account during the refinement.

scholarly journals Crystal structure of 1,3-bis(1H-benzotriazol-1-ylmethyl)benzene

2016 ◽  
Vol 72 (6) ◽  
pp. 815-818 ◽  
Author(s):  
Mario A. Macías ◽  
Nelson Nuñez-Dallos ◽  
John Hurtado ◽  
Leopoldo Suescun
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Aromatic Ring ◽  
Title Compound ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Dihedral Angles ◽  
Benzene Nucleus ◽  
Π Interactions ◽  
Compound C

The molecular structure of the title compound, C20H16N6, contains two benzotriazole units bonded to a benzene nucleus in ametaconfiguration, forming dihedral angles of 88.74 (11) and 85.83 (10)° with the central aromatic ring and 57.08 (9)° with each other. The three-dimensional structure is controlled mainly by weak C—H...N and C—H...π interactions. The molecules are connected in inversion-related pairs, forming the slabs of infinite chains that run along the [-110] and [110] directions.

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