scholarly journals Study on the Structural Characteristics of Bird Necks and Their Static Motion Features in the Sagittal Plane

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1228
Author(s):  
Jiajia Wang ◽  
Wenfeng Jia ◽  
Fu Zhang ◽  
Xiqiang Ma ◽  
Zhaomei Qiu ◽  
...  
Keyword(s):  
Sagittal Plane ◽  
Structural Characteristics ◽  
Structural Parameters ◽  
Measuring Method ◽  
Structural Features ◽  
Theoretical Concept ◽  
Natural Motion ◽  
General Law ◽  
Dimensional Parameters ◽  
Motion Characteristics

The necks of birds that possess complex structures, graceful curves, and flexible movements are perfect natural motion actuators. Studying their structural features, mechanic characteristics, and motion rules can provide valuable references for imitating such actuators and motion functions artificially. Previous studies have analyzed the influence of two-dimensional motion geometric features and anatomical structure of the neck on motion efficiency and motion stability. However, the mechanism of motion flexibility from the perspective of neck structure has not been investigated. This study investigates the general law of the relationship between the structural parameters and motion characteristics of birds’ necks using tomography technology and 3D reconstruction technology. The results show that the structural characteristics of geese and ducks are similar, and there are significant differences in joint motion characteristics. Geese obtains complex neck postures through active intervertebral joints and highly flexible facet joints and possesses higher neck flexibility than ducks. This study provides a generic measuring method for obtaining birds’ cervical spinal vertebral structural dimensional parameters and offers a new theoretical concept for bionic robotic structural design and manufacture.

171Intravascular polarimetry in patients with coronary artery disease: a first-in-human pilot study

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
K Otsuka ◽  
M Villiger ◽  
A Karanasos ◽  
L J C Van Zandvoort ◽  
P Doradla ◽  
...  
Keyword(s):  
Pilot Study ◽  
Clinical Presentation ◽  
Structural Characteristics ◽  
Structural Parameters ◽  
Structural Features ◽  
Plaque Morphology ◽  
Cross Sectional ◽  
Research Fellowship ◽  
Coronary Syndrome ◽  
Insight Into

Abstract Background Polarization-sensitive (PS-) optical frequency domain imaging (OFDI) measures polarization properties of tissue together with conventional cross-sectional OFDI images of subsurface microstructure. PS-OFDI offers refined insight into plaque morphology and composition, which are implicated in the pathogenesis of acute coronary syndromes (ACS). Purpose This first-in-human pilot study of intravascular polarimetry aimed to investigate birefringence and depolarization features of coronary plaques in patients and to examine the relationship of these features with established structural characteristics available to conventional OFDI and with clinical presentation. Methods 30 patients undergoing PS-OFDI (acute coronary syndrome; ACS, n=12 and stable angina pectoris; SAP, n=18) participated in this study. 342 cross-sectional images evenly distributed along all imaged coronary arteries were classified into one of seven plaque categories according to conventional OFDI. Polarization features averaged over the entire intimal area of each cross-section were compared between plaque types and with structural parameters. Further, we assessed the polarization properties in the fibrous caps of ACS and SAP culprit lesions and compared them with structural features using a generalized linear model. Results The median birefringence and depolarization showed statistically significant differences among plaque types (both p<0.001, one-way ANOVA). Depolarization significantly differed between individual plaque types (p<0.05), except between fibro-fatty and fibro-calcified plaques. Caps of ACS lesions and ruptured caps exhibited lower birefringence than caps of SAP lesions (p<0.01). In addition to clinical presentation, cap birefringence also associated with macrophage accumulation as assessed by normalized standard deviation. Intravascular polarimetry Conclusions Intravascular polarimetry provides quantitative metrics that help to characterize coronary arterial tissues and may offer refined insight into coronary arterial atherosclerotic lesions in patients (Figure). Quantitative assessment of plaque polarization properties by intravascular polarimetry may open new avenues for studying plaque progression and detecting high-risk patients. Acknowledgement/Funding The JSPS Overseas Research Fellowship, the Uehara Memorial Foundation, and the Japan Heart Foundation and Bayer Yakuhin

scholarly journals Novel Dihydro-1,3,2H-benzoxazine Derived from Furfurylamine: Crystal Structure, Hirshfeld Surface Analysis, Photophysical Property, and Computational Study

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 568
Author(s):  
Worawat Wattanathana ◽  
Yuranan Hanlumyuang ◽  
Suttipong Wannapaiboon ◽  
Kantapat Chansaenpak ◽  
Piyanut Pinyou ◽  
...  
Keyword(s):  
Computational Study ◽  
Structural Characteristics ◽  
Structural Parameters ◽  
Photophysical Properties ◽  
Chair Conformation ◽  
Structural Features ◽  
Vital Role ◽  
One Pot ◽  
Td Dft ◽  
Oxazine Ring

Dihydro-1,3,2H-benzoxazines (or benzoxazine monomers) are a class of compounds that have been widely utilized in many areas such as the production of the functional polymers and optoelectronic materials. The structure variety of the benzoxazines plays a vital role in their desired properties. The effort of synthesizing functionalized benzoxazines from bioresources is of interest for sustainable development. Herein, we report the synthesis of the novel benzoxazine monomer referred to as 3-(furan-2-ylmethyl)-6-methyl-3,4-dihydro-2H-benzo[e][1,3]oxazine or benzoxazine (I) from a one-pot Mannich reaction using p-cresol, paraformaldehyde, and furfurylamine (a bio-derived amine). An X-ray crystallographic study was performed at low temperature (100 K) to obtain the structural characteristics of the benzoxazine (I). The result reveals that the oxazine ring adopts a half chair conformation to locate all the members of the benzoxazine ring as planar as possible by employing the expansion of the bond angles within the ring. Apart from the structural parameters, the intermolecular interactions were also examined. It was found that the significant interactions within the crystal are C–H···N, C–H···O, and the C–H···π interactions. The C–H···N interactions link the benzoxazine (I) molecules into an infinite molecular chain, propagating along the [100] direction. Hirshfeld surfaces and their corresponding fingerprint plots were comprehensively analyzed to confirm and quantify the significance of these interactions. Moreover, the photophysical properties of the benzoxazine (I) were investigated in solvents with various polarities. The corresponding relations between the structural features, frontier molecular orbitals, and absorption-and-emission characteristics were proposed and explained according to the DFT and TD-DFT calculations.

scholarly journals Coupled Fluid–Solid Numerical Simulation for Flow Field Characteristics and Supporting Performance of Flexible Support Cylindrical Gas Film Seal

Aerospace ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 97
Author(s):  
Junfeng Sun ◽  
Meihong Liu ◽  
Zhen Xu ◽  
Taohong Liao ◽  
Xiangping Hu ◽  
...  
Keyword(s):  
Flow Field ◽  
Film Thickness ◽  
Fluid Dynamic ◽  
Structural Characteristics ◽  
Structural Parameters ◽  
Equivalent Stress ◽  
Three Dimensional ◽  
High Rotational Speed ◽  
Flexible Support ◽  
Flow Field Characteristics

A new type of cylindrical gas film seal (CGFS) with a flexible support is proposed according to the working characteristics of the fluid dynamic seal in high-rotational-speed fluid machinery, such as aero-engines and centrifuges. Compared with the CGFS without a flexible support, the CGFS with flexible support presents stronger radial floating characteristics since it absorbs vibration and reduces thermal deformation of the rotor system. Combined with the structural characteristics of a film seal, an analytical model of CGFS with a flexible wave foil is established. Based on the fluid-structure coupling analysis method, the three-dimensional flow field of a straight-groove CGFS model is simulated to study the effects of operating and structural parameters on the steady-state characteristics and the effects of gas film thickness, eccentricity, and the number of wave foils on the equivalent stress of the flexible support. Simulation results show that the film stiffness increases significantly when the depth of groove increases. When the gas film thickness increases, the average equivalent stress of the flexible support first decreases and then stabilizes. Furthermore, the number of wave foils affects the average foils thickness. Therefore, when selecting the number of wave foils, the support stiffness and buffer capacity should be considered simultaneously.

A Study of the Anchor Effect Based on Structural Parameters of Flexible Pressurized Anchor and Pressure from Surrounding Rock

2011 ◽  
Vol 71-78 ◽  
pp. 4634-4637
Author(s):  
Tian Lin Cui ◽  
Jing Kun Pi ◽  
Yong Hui Liu ◽  
Zhen Hua He
Keyword(s):  
Structural Parameters ◽  
Structural Features ◽  
Surrounding Rock ◽  
Design Parameters ◽  
Optimized Design ◽  
Anchor Effect ◽  
The Finite Element Method ◽  
Anchor System ◽  
New Type ◽  
Stress Relation

In order to optimize the design of flexible pressurized anchor, this paper gives a further analysis on structural features of the new type of flexible pressurized anchor and carries out a contact analysis on anchor system by using the finite element method. It calculates as well as researches the contact stress relation of interactional anchor rod and surrounding rock under the circumstance of anchoring, obtaining the law of all major design parameters of anchor rod structure and pressure from surrounding rock influencing the anchoring performance and arriving at the conclusion that the anchor rod is adapted to various conditions of surrounding rock. They not only serve as important references for optimized design and application of anchor rod, but also provide a basis for the experiment of new type of anchor rod.

Synthetic Transfer Zone Characterization Using Seismic Attributes: An Example from the Parihaka Fault System in the Taranaki Basin, New Zealand.

2021 ◽  
pp. 1-73
Author(s):  
Pierre Karam ◽  
Shankar Mitra ◽  
Kurt Marfurt ◽  
Brett M. Carpenter
Keyword(s):  
New Zealand ◽  
Structural Characteristics ◽  
Structural Parameters ◽  
Seismic Attributes ◽  
Fault System ◽  
Structural Interpretation ◽  
Transfer Zones ◽  
Seismic Characterization ◽  
The Individual ◽  
Transfer Zone

Synthetic transfer zones develop between fault segments which dip in the same direction, with relay ramps connecting the fault blocks separated by the different fault segments. The characteristics of the transfer zones are controlled by the lithology, deformation conditions, and strain magnitude. The Parihaka fault is a NE-SW trending set of three major en-echelon faults connected by relay ramps in the Taranaki Basin, New Zealand. The structure in the basin is defined by extension during two episodes of deformation between the late Cretaceous and Paleocene and between the Late Miocene and recent. To better understand the evolution of a synthetic transfer zone, we study the geometry and secondary faulting between the individual fault segments in the Parihaka fault system using structural interpretation of 3D seismic data and seismic attributes. This interpretation allows for a unique application of seismic attributes to better study transfer zones. Seismic attributes, including coherence, dip, and curvature are effective tools to understand the detailed geometry and variation in displacement on the individual faults, the nature of secondary faulting along the transfer zones, and the relationship between the faults and drape folds. Seismic characterization of the fault system of Miocene to Pliocene age horizons highlights variations in the degree of faulting, deformation, and growth mechanism associated with different stages of transfer zone development. Coherence, dip, and curvature attributes show a direct correlation with structural parameters such as deformation, folding, and breaching of relay ramps.. All three attributes enhance the visualization of the major and associated secondary faults and better constrain their tectonic history. The observed correlation between seismic attributes and structural characteristics of transfer zones can significantly improve structural interpretation and exploration workflow.

QSAR AND PHARMACOPHORE MODELING OF 4-ARYLTHIENO [3, 2-d] PYRIMIDINE DERIVATIVES AGAINST ADENOSINE RECEPTOR OF PARKINSON'S DISEASE

2010 ◽  
Vol 09 (06) ◽  
pp. 975-991 ◽  
Author(s):  
SHIEK S. S. J. AHMED ◽  
A. AHAMEETHUNISA ◽  
WINKINS SANTOSH
Keyword(s):  
Structural Parameters ◽  
Pharmacophore Model ◽  
Structural Features ◽  
Pharmacophore Modeling ◽  
Hydrogen Bond Donor ◽  
Pyrimidine Derivatives ◽  
Antagonist Activity ◽  
Qsar Studies ◽  
Adenosine A1 ◽  
Adenosine A2a

A series of 47, 4-arylthieno[3, 2-d] pyrimidine derivatives was subjected to quantitative structure-antiparkinson activity relationships (QSAR) studies to evaluate the antagonist activity towards both adenosine A1 and adenosine A2A targets in Parkinson's drug discovery. QSAR models were derived with the aid of genetic function approximation (GFA) technique using descriptors to make connections between structural parameters and antiparkinson's activity followed by ADMET analysis and pharmacophore model generation. QSAR model was assessed using a test set of 12 compounds for A1 (r2 pred = 0.961), (q2 = 0.912) and 12 compounds for A2a (r2 pred = 0.914), (q2 = 0.781) receptor. The results revealed the significant role of DIPOLE MAG, CHI-V-3-P, WIENER, AREA, SC-2 and PHI-MAG descriptors in the antiparkinson activity of the studied compounds against adenosine A1 and adenosine A2A receptors. Subsequent, ADMET analysis shows 28 compounds can be the better candidates of drug and execution of pharmacophore model, explores the hydrogen bond donor, aromatic ring and hydrophobic groups are the key structural features for the antagonist activity.

Abstract TP436: Dysfunctional Cerebral Neovascularization And Remodeling Patterns In Obese And Lean Models Of Type 2 Diabetes

Stroke ◽  
2013 ◽  
Vol 44 (suppl_1) ◽  
Author(s):  
Roshini Prakash ◽  
Maribeth Johnson ◽  
Susan C Fagan ◽  
Adviye Ergul
Keyword(s):  
Type 2 Diabetes ◽  
Glycemic Control ◽  
Structural Characteristics ◽  
Structural Parameters ◽  
Volume Density ◽  
3 Dimensional ◽  
Gk Rats ◽  
Dimensional Reconstruction ◽  
Branch Density

We previously reported intense pial cerebral collateralization and arteriogenesis in a mild and lean model of type 2 diabetes, Goto-Kakizaki (GK) rats. Further 3-dimensional fluroscein (FITC) imaging studies revealed regional differences in increased cerebral neovascularization which was associated with poor vessel wall maturity. Building upon these findings, the goals of this study were a) to compare and contrast this pathological neovascularization pattern in db/db mice and GK models of diabetes, and b) determine the effect of glycemic control on erratic cerebral neovascularization. Total vascular volume, density and surface area as well as structural parameters including microvessel/macrovessel ratio, non-FITC perfusing vessel abundance, penetrating arteriole (PA) branching density and diameter, and tortuosity were measured by 3 dimensional reconstruction of FITC stained vasculature using Z-stacked images obtained with confocal microscopy. Lean GK rats exhibited an increase in both micro and macrovessel density, non-perfusing vessel abundance, branch density, diameter and tortuosity. Glycemic control with metformin prevented these changes. Obese db/db mice, on the other hand, showed an increase in only microvascular density but this was not associated with an increase in non-FITC perfusing vessels. PA branch density was higher than controls but branch diameter was reduced. Diabetes also promoted astrogliosis. These results suggests that type 2 diabetes leads to cerebral neovascularization and remodeling but structural characteristics of newly formed vessels differ between lean and obese models that have mild or severe hyperglycemia, respectively. The prevention of dysfunctional cerebral neovascularization by early glucose control suggests that hyperglycemia is a mediator of this response. N=4-8 * p≤ 0.05, ** p≤ 0.005 *** 0.0005

Optimal Design of Composite Material Maintenance Structure for Aircraft Based on ANSYS Workbench

2021 ◽  
Vol 871 ◽  
pp. 216-221
Author(s):  
Jing Tao Dai ◽  
Pei Zhong Zhao ◽  
Hong Bo Su ◽  
Hao Dong Liu ◽  
Yu Bo Wang ◽  
...  
Keyword(s):  
Finite Element ◽  
Composite Material ◽  
Optimal Design ◽  
Structural Characteristics ◽  
Structural Parameters ◽  
Element Model ◽  
Composite Cement ◽  
Composite Patch ◽  
Length Width ◽  
Ansys Workbench

Composite material is widely used to maintain damaged structures of aircraft. The 3D finite element model of composite cement maintenance for aircraft is established by finite element method software ANSYS Workbench. The structural characteristics and usage status of the composite cement maintenance model is analyzed, and then the optimal structural parameters of the composite patch are obtained, including the length, width and thickness. The results show that the composite cement maintenance method could effectively restore the rigidity, and improve the strength of the structure. Furthermore, the optimal design for composite patch ensures safety of aircraft, economics of maintenance, and operability of repair methods.

scholarly journals Three Structural Features of Functional Food Components and Herbal Medicine with Amyloid β42 Anti-Aggregation Properties

Molecules ◽  
2019 ◽  
Vol 24 (11) ◽  
pp. 2125 ◽  
Author(s):  
Kazuma Murakami ◽  
Kazuhiro Irie
Keyword(s):  
Amino Acid ◽  
Functional Food ◽  
Structural Characteristics ◽  
Salt Bridge ◽  
Basic Amino Acid ◽  
Structural Features ◽  
Amino Acid Residues ◽  
Treatment And Prevention ◽  
Food Components ◽  
Underlying Mechanisms

Aggregation of amyloid β42 (Aβ42) is one of the hallmarks of Alzheimer’s disease (AD). There are numerous naturally occurring products that suppress the aggregation of Aβ42, but the underlying mechanisms remain to be elucidated. Based on NMR and MS spectroscopic analysis, we propose three structural characteristics found in natural products required for the suppressive activity against Aβ42 aggregation (i.e., oligomerization by targeting specific amino acid residues on this protein). These characteristics include (1) catechol-type flavonoids that can form Michael adducts with the side chains of Lys16 and 28 in monomeric Aβ42 through flavonoid autoxidation; (2) non-catechol-type flavonoids with planarity due to α,β-unsaturated carbonyl groups that can interact with the intermolecular β-sheet region in Aβ42 aggregates, especially aromatic rings such as those of Phe19 and 20; and (3) carboxy acid derivatives with triterpenoid or anthraquinoid that can generate a salt bridge with basic amino acid residues such as Lys16 and 28 in the Aβ42 dimer or trimer. Here, we summarize the recent body of knowledge concerning amyloidogenic inhibitors, particularly in functional food components and Kampo medicine, and discuss their application in the treatment and prevention of AD.

The Structure, Microhardness and Wear Resistance of Coatings Obtained through Non-Vacuum Electron Beam Cladding of Chromium and Titanium Carbides on Low Carbon Steel

2018 ◽  
Vol 927 ◽  
pp. 13-19 ◽  
Author(s):  
Tatyana A. Krylova ◽  
Konstantin V. Ivanov ◽  
Vladimir E. Ovcharenko
Keyword(s):  
Wear Resistance ◽  
Electron Beam ◽  
Carbon Steel ◽  
Volume Fraction ◽  
Structural Characteristics ◽  
Low Carbon Steel ◽  
Structural Features ◽  
Low Carbon ◽  
Indentation Tests ◽  
Titanium Carbides

An interrelation between structural features, microhardness and wear resistance was studied in the coatings obtained by non-vacuum relativistic electron beam cladding of chromium and titanium carbides powder mixture on low carbon steel. Five coatings differing in the amount of the entered energy were investigated using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), indentation tests and wear resistance measurements. It was found that the concentration of alloying elements both in solid solution and eutectic as well as the volume fraction of eutectic are the main structural characteristics which defines the microhardness of the coatings. The distribution of TiC phase plays a key role in the resistance to wear.

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