scholarly journals Scaffold Library for Tissue Engineering: A Geometric Evaluation

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Nattapon Chantarapanich ◽  
Puttisak Puttawibul ◽  
Sedthawatt Sucharitpwatskul ◽  
Pongnarin Jeamwatthanachai ◽  
Samroeng Inglam ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Stress Level ◽  
Computer Aided Design ◽  
High Stress ◽  
Fe Method ◽  
Intersection Index ◽  
Truncated Octahedron ◽  
Beam Thickness ◽  
High Stress Level ◽  
Aided Design

Tissue engineering scaffold is a biological substitute that aims to restore, to maintain, or to improve tissue functions. Currently available manufacturing technology, that is, additive manufacturing is essentially applied to fabricate the scaffold according to the predefined computer aided design (CAD) model. To develop scaffold CAD libraries, the polyhedrons could be used in the scaffold libraries development. In this present study, one hundred and nineteen polyhedron models were evaluated according to the established criteria. The proposed criteria included considerations on geometry, manufacturing feasibility, and mechanical strength of these polyhedrons. CAD and finite element (FE) method were employed as tools in evaluation. The result of evaluation revealed that the close-cellular scaffold included truncated octahedron, rhombicuboctahedron, and rhombitruncated cuboctahedron. In addition, the suitable polyhedrons for using as open-cellular scaffold libraries included hexahedron, truncated octahedron, truncated hexahedron, cuboctahedron, rhombicuboctahedron, and rhombitruncated cuboctahedron. However, not all pore size to beam thickness ratios (PO : BT) were good for making the open-cellular scaffold. The PO : BT ratio of each library, generating the enclosed pore inside the scaffold, was excluded to avoid the impossibility of material removal after the fabrication. The close-cellular libraries presented the constant porosity which is irrespective to the different pore sizes. The relationship between PO : BT ratio and porosity of open-cellular scaffold libraries was displayed in the form of Logistic Power function. The possibility of merging two different types of libraries to produce the composite structure was geometrically evaluated in terms of the intersection index and was mechanically evaluated by means of FE analysis to observe the stress level. The couples of polyhedrons presenting low intersection index and high stress level were excluded. Good couples for producing the reinforced scaffold were hexahedron-truncated hexahedron and cuboctahedron-rhombitruncated cuboctahedron.

Implementation of K-Modes Algorithm for Clustering of Stress Causes in University Students

2021 ◽  
Vol 9 (3) ◽  
pp. 419
Author(s):  
Ni Putu Mira Novita Dewi ◽  
Ida Bagus Gede Dwidasmara
Keyword(s):  
Stress Level ◽  
Clustering Algorithm ◽  
High Stress ◽  
Optimal Number ◽  
Mild Stress ◽  
Student Groups ◽  
High Stress Level ◽  
Internal And External Factors ◽  
Python Programming ◽  
Cluster 2

Stress is an inevitable part of life in a college environment. The variety of factors that cause stress in students, it is necessary to cluster the factors that cause stress in students to see the description of the characteristics of each cluster of students. The clustering process is carried out to identify the causes of stress in student groups and their relationship to these internal and external factors. Cluster analysis can be used as a reference to decide on efforts to handle and prevent increased stress in students. The clustering process is carried out using the Python programming language. The algorithm used is the k-modes clustering algorithm. This algorithm is suitable for clustering categorical data. The optimal number of clusters obtained from the implementation of the elbow method is three clusters. Cluster 1 is a cluster with a mild stress level, the main cause of stress is academic issues. Cluster 1 is the only group where the majority of the cause of stress is not financial. Cluster 2 is a cluster with a high stress level which causes various stressors. However, cluster 2 is the only cluster where the cause of stress is on careers and on involvement in hostels, clubs, and society. Cluster 3 is a cluster with a medium stress level. This cluster is the only cluster dominated by male gender. The main cause of stress in this cluster is academic and financial.

scholarly journals Study on the Effect of Laser Quenching on Fretting Fatigue Life

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 566 ◽  
Author(s):  
Hongjian Zhang ◽  
Xufeng Yang ◽  
Haitao Cui ◽  
Weidong Wen
Keyword(s):  
Fatigue Life ◽  
Stress Level ◽  
High Stress ◽  
Fretting Fatigue ◽  
Test System ◽  
Experimental Results ◽  
Laser Quenching ◽  
Error Band ◽  
Hydraulic Servo ◽  
High Stress Level

Laser quenching hardening is one of the most used surface treated technologies. In order to study the effect of laser quenching on the fretting fatigue life, fretting fatigue experiments of TC11 (Ti-6.5Al-1.5Zr-3.5Mo-0.3Si) titanium alloy specimens with different surface conditions were carried out on a special hydraulic servo fatigue test system. The experimental results showed that laser quenching hardening has a good performance in increasing the fretting fatigue lives of the TC11 alloy. However, the effects of laser quenching on fretting fatigue are more obviously at low stress level than at high stress level, the fretting fatigue life was increased by 110.78% at low stress level and 17.56% at high stress level, respectively. Based on the critical plane approach, the traditional SWT (Smith–Watson–Topper) parameter was modified and used to describe the fretting fatigue life of the TC11 alloy after hardening by the consideration of the variations of the hardening layer’s elastic modulus. Compared with the experimental results, all the errors of the predicted results lied in the error band of two.

Genetic susceptibility of CYP1A1 gene and risk of pesticide exposure in prostate cancer

2020 ◽  
Vol 29 (4) ◽  
pp. 429-440
Author(s):  
Amar Abhishek ◽  
Nasreen Ghaji Ansari ◽  
Vishwajeet Singh ◽  
Rahul Janak Sinha ◽  
Prabhakar Mishra ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Stress Level ◽  
Genetic Factors ◽  
Pesticide Exposure ◽  
High Stress ◽  
P Value ◽  
Specific Pcr ◽  
Cyp1a1 Gene ◽  
High Stress Level ◽  
High Level

BACKGROUND: The etiology of prostate cancer (PCa) is multi-factorial including environmental and genetic factors. Present study evaluates the association between level of pesticides, stress level and CYP1A1 gene polymorphism with PCa patients. METHODS: A case control study was conducted with 102 PCa patients and age match symptomatic (n= 107) and asymptomatic benign prostatic hyperplasia (BPH, n= 70) patients. Pesticide level was characterized by Gas Chromatography. The oxidative stress and scavenging mechanisms were determined by biochemical method. Two polymorphisms of CYP1A1 gene, rs4646903 and rs1048943, were analyzed by polymerase chain reaction (PCR) followed by restriction fragment length polymorphism and allele specific PCR method. RESULTS: Higher level of pesticide namely beta-hexachlorocyclohexane (β-HCH), Malathion, Chlorpyrifos and Fenvalerate were found in PCa group (all p value: < 0.05). Kruskal Wallis H test depicted that level of β-HCH and Malathion significantly correlated with higher grade of PCa (all p< 0.05). The PCa Patients with simultaneously low antioxidant activity and high stress level tended to suffer worst clinical outcomes. Dominant model of rs4646903 and rs1048943 suggested that substitution is associated with a higher risk of PCa (OR: 2.2, CI: 1.6–3.8, p: 0.009 and OR: 1.95, CI: 1.1–3.4, p: 0.026; respectively) and this risk was also influenced by smoking and pesticide exposure. CONCLUSION: Environmental and genetic factors are reported to raise risk; person with high level of these pesticides especially in high risk genotype might be more susceptible to PCa.

Distress screening in patients with urogenital malignancies.

2017 ◽  
Vol 35 (6_suppl) ◽  
pp. 412-412
Author(s):  
Pia Paffenholz ◽  
Maria Angerer-Shpilenya ◽  
Johannes Salem ◽  
David Pfister ◽  
Axel Heidenreich
Keyword(s):  
Psychological Distress ◽  
Stress Level ◽  
Malignant Tumors ◽  
High Stress ◽  
Salvage Treatment ◽  
Distress Screening ◽  
Prospective Longitudinal Study ◽  
Psychological Burden ◽  
High Stress Level ◽  
Prospective Longitudinal

412 Background: Malignant tumors do not only have a somatic but also a psychological impact on patients. To date, only a few studies are available which evaluated the potential psychological burden of patients suffering from urogenital cancers. In this prospective, longitudinal study we examine the baseline psychological distress of patients treated for urogenital malignancies focussing on testicular cancer (TC) and prostate cancer (PCA). Methods: Psychological distress of 192 inpatients treated for urogenital malignancies was evaluated using the distress thermometer (DT), an established tool for the detection of distress, prior to any surgical or systemic therapy. The DT consists of a visual analogue scale ranging from 0 to 10 resulting in a low (0-3), moderate (4-6) or high (7-10) stress level. Furthermore, it contains a 36-item list of problems subdivided into 5 categories (practical, family, emotional, spiritual/religious, physical). Results: The mean DT score was 5 (interquartile range (IQR) 3-7) with the most common stressors being of emotional origin, namely fear (50%), worry (44%), nervousness (42%), sleep disorders (39%) and fatigue (32%). DT analysis did not reveal any difference between the tumor entities but 64% of all patients displayed a moderate to high stress level requiring psycho-oncological support. The comparison of PCA and TC demonstrated a higher distress level in PCA patients in the subgroups of metastatic disease (median 5.5, IQR 4-8 vs. median 4, IQR 2-6; p = 0.018), secondary therapy (median 6, IQR 5-8 vs. median 4.5, IQR 2.75-6; p = 0.023) and salvage treatment (median 7, IQR 4.5-9 vs. 5, IQR 2.75-6; p = 0.021). PCA patients receiving salvage treatment displayed significantly higher distress levels compared to non-salvage treated patients (median 7, IQR 4.5-9 vs. median 5, IQR 2-7; p 0.028). Conclusions: Our study shows that 64% of urological tumor patients should be offered psycho-oncological support. Especially patients suffering from advanced stage PCA seem to have a high stress level. Thus, physicians in the field of urologic oncology should be aware of their patients’ psychological distress in order to identify high-risk patients and provide them with an appropriate psycho-oncological support.

scholarly journals Design by chip: Computer-aided tissue engineering

2007 ◽  
Vol 29 (1) ◽  
pp. 20-23
Author(s):  
Jae Nam, Binil Starly and Wei Sun
Keyword(s):  
Tissue Engineering ◽  
Computer Aided Design ◽  
Medical Image ◽  
Computational Analysis ◽  
Medical Image Processing ◽  
Cellular Tissue ◽  
Computer Aided ◽  
Disciplinary Field ◽  
Organ Level ◽  
Aided Design

Computer-aided tissue engineering (CATE) is an evolving, multi-disciplinary field that utilizes the tools of medical image processing, computer-aided design (CAD), computational analysis, multiscale modelling and biomanufacturing for the purposes of tissue engineering. The merging of computation and automation with tissue engineering could have the potential for profound advances in developing tissue replacements and also in better understanding of physiology and pathology at a cellular, tissue, and organ level.

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