scholarly journals The role of the circle of Willis in internal carotid artery stenosis and anatomical variations: a computational study based on a patient-specific three-dimensional model

2015 ◽  
Vol 14 (1) ◽  
Author(s):  
Guangyu Zhu ◽  
Qi Yuan ◽  
Jian Yang ◽  
Joon Hock Yeo
Keyword(s):  
Carotid Artery ◽  
Internal Carotid ◽  
Computational Study ◽  
Three Dimensional ◽  
Anatomical Variations ◽  
Internal Carotid Artery Stenosis ◽  
Patient Specific ◽  
Dimensional Model ◽  
Three Dimensional Model

scholarly journals Substrate (aglycone) specificity of human cytosolic beta-glucosidase

2003 ◽  
Vol 373 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Jean-Guy BERRIN ◽  
Mirjam CZJZEK ◽  
Paul A. KROON ◽  
W. Russell MCLAUCHLAN ◽  
Antoine PUIGSERVER ◽  
...  
Keyword(s):  
Structural Model ◽  
Homology Modelling ◽  
Three Dimensional ◽  
Amino Acid Residues ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Mutant Proteins ◽  
Metabolizing Enzyme ◽  
Beta Glucosidase

Human cytosolic β-glucosidase (hCBG) is a xenobiotic-metabolizing enzyme that hydrolyses certain flavonoid glucosides, with specificity depending on the aglycone moiety, the type of sugar and the linkage between them. Based upon the X-ray structure of Zea mays β-glucosidase, we generated a three-dimensional model of hCBG by homology modelling. The enzyme exhibited the (β/α)8-barrel fold characteristic of family 1 β-glucosidases, with structural differences being confined mainly to loop regions. Based on the substrate specificity of the human enzymes, sequence alignment of family 1 enzymes and analysis of the hCBG structural model, we selected and mutated putative substrate (aglycone) binding site residues. Four single mutants (Val168→Tyr, Phe225→Ser, Tyr308→Ala and Tyr308→Phe) were expressed in Pichia pastoris, purified and characterized. All mutant proteins showed a decrease in activity towards a broad range of substrates. The Val168→Tyr mutation did not affect Km on p-nitrophenyl (pNP)-glycosides, but increased Km 5-fold on flavonoid glucosides, providing the first biochemical evidence supporting a role for this residue in aglycone-binding of the substrate, a finding consistent with our three-dimensional model. The Phe225→Ser and Tyr308→Ala mutations, and, to a lesser degree, the Tyr308→Phe mutation, resulted in a drastic decrease in specific activities towards all substrates tested, indicating an important role of those residues in catalysis. Taken together with the three-dimensional model, these mutation studies identified the amino-acid residues in the aglycone-binding subsite of hCBG that are essential for flavonoid glucoside binding and catalysis.

The Parametric Analysis of the Threshold Value Judging Mechanism in MEMS Safety and Arming Device

2015 ◽  
Vol 645-646 ◽  
pp. 968-971
Author(s):  
Fu Fu Wang ◽  
Wen Zhong Lou ◽  
Fang Yi Liu ◽  
Da Kui Wang ◽  
Ming Rong Zhang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Threshold Value ◽  
Element Model ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Long Distance ◽  
And Control ◽  
The Mathematical Model ◽  
The Finite Element Model

In this paper, a mechanical MEMS S&A device has been proposed. The size of the device is 10mm×13mm×0.5mm. The role of the threshold value judging mechanism is to determine the environment suffered by centrifugal force and control the sub-centrifugal slider not movement under the threshold, so as to effectively guarantee the time of long-distance arming. Through establishing the three-dimensional model of threshold value judging mechanism, establishing the force and the parameters of locking-releasing mechanism, deriving the mathematical model according to the rigid dynamic mechanics theory and establishing the finite element model by using ANSYS/LS-DYNA, appropriate threshold value judging mechanism is designed to meet two items, one item is the deformation of threshold value rod is not enough to release sub-centrifugal slider when the speed is less than 60000r/min; the other item is deformation of threshold value rod can release sub-centrifugal slider when the speed is more than 60000r/min.

scholarly journals A multiscale model for the study of cardiac biomechanics in single-ventricle surgeries: a clinical case

2015 ◽  
Vol 5 (2) ◽  
pp. 20140079 ◽  
Author(s):  
Alessio Meoli ◽  
Elena Cutrì ◽  
Adarsh Krishnamurthy ◽  
Gabriele Dubini ◽  
Francesco Migliavacca ◽  
...  
Keyword(s):  
Clinical Case ◽  
Single Ventricle ◽  
Three Dimensional ◽  
Multiscale Model ◽  
Patient Specific ◽  
Complex Congenital Heart Disease ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Sequential Approach ◽  
Lp Model

Complex congenital heart disease characterized by the underdevelopment of one ventricular chamber (single ventricle (SV) circulation) is normally treated with a three-stage surgical repair. This study aims at developing a multiscale computational framework able to couple a patient-specific three-dimensional finite-element model of the SV to a patient-specific lumped parameter (LP) model of the whole circulation, in a closed-loop fashion. A sequential approach was carried out: (i) cardiocirculatory parameters were estimated by using a fully LP model; (ii) ventricular material parameters and unloaded geometry were identified by means of the stand-alone, three-dimensional model of the SV; and (iii) the three-dimensional model of SV was coupled to the LP model of the circulation, thus closing the loop and creating a multiscale model. Once the patient-specific multiscale model was set using pre-operative clinical data, the virtual surgery was performed, and the post-operative conditions were simulated. This approach allows the analysis of local information on ventricular function as well as global parameters of the cardiovascular system. This methodology is generally applicable to patients suffering from SV disease for surgical planning at different stages of treatment. As an example, a clinical case from stage 1 to stage 2 is considered here.

scholarly journals The Model of Digital Cartographic Layers of Different Scales to Calculate the Ratios of Cartographic Generalizations: An Applied Study to Anah City

2021 ◽  
Vol 16 (7) ◽  
pp. 1245-1252
Author(s):  
Zuhair Jaber Mushref ◽  
Ameer Mohammed Khalaf ◽  
Salah Othman Abed Al-Ani
Keyword(s):  
Three Dimensional ◽  
Land Uses ◽  
Dimensional Model ◽  
Functional Importance ◽  
Three Dimensional Model ◽  
Applied Study ◽  
Digital Cartography ◽  
Accurate Perception ◽  
Modern Technologies

The research aims to give an accurate perception of the role of modern technologies, represented by geographic information systems, in extracting data and information, and then building a geographical database for urban land uses in an Ana city to reach generalized models based on the source map with a scale of 1/5000 and then building generalized models through The application of digital generalization elements according to the different standards adopted in the research (1/10000, 1/25000, 1/50000, 1/100000) in order to reach the end to the best results in the cartographic production of these models in a way that facilitates the process of understanding and perception by finding The most appropriate way to represent this data on a map according For the functional importance of each of the uses through disposal to eliminate overlap between uses Depending on the generalization elements of selecting, deleting, simplifying, smoothing, coding and exaggeration, and finally, as The research showed that there is a difference in the areas, uses and preparation of methods when moving from one scale to another. the research concluded by building a three-dimensional model to simulate the natural process of generalizing digital cartography according to different scales.

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