摘要: Foot temperature can be affected by friction and contact pressure, in this study, we explored the specific changes of foot temperature under different friction conditions, running with socks versus no socks. The relationship between vertical loading force and foot temperature will also be investigated at the same time. Ten male recreational runners wore the same shoes and socks and were tested running 8km/h on a treadmill. The plantar temperature during running was recorded every 3 minutes for a total of 45 minutes. Post-run temperature change was recorded every 3 minutes for 12 minutes. The plantar pressure was recorded before running and at the first 15 minutes during running. The subjects with socks and no socks were tested on separate occasions. There were no significant differences found between the socks and no socks conditions. However, central metatarsal head, lateral metatarsal head, medial rearfoot and lateral rearfoot regions exist differences were reflected at the first 6minutes-12minutes of running. The foot temperature became more stable after 15minutes of running. Also, plantar pressure increased significantly in the hallux, other toes, first metatarsal head and central metatarsal regions. It also could conclude that lower initial temperature had a greater increase trend during the running start stage. When the ankle in plantarflexion stage, toe and forefoot regions showed a higher rise in temperature and also presented higher plantar pressure correspondingly.
摘要: Calcium-silicate cement mainly based on dicalcium-silicate (C2S) was synthesized by the mean of solid state reaction. Beta-C3P was added to C2S to obtain C2S-C3P. Zinc oxide and bismuth oxide was incorporated to prepare radioc cement. In this work, the bioactivity and the mechanical strength of the synthesized cement were investigated. The in vitro test was carried out by immersion of cement pastilles in the artificial saliva in different periods from 4 hours to 30 days. Whereas the mechanical strength of some samples was operated at 28 and 72 days. The specimens are characterized by X-ray diffraction , Infrared spectroscopy and scanning electron microscopy. The finding results indicated that hydroxyapatite may appear after 24 hours of soaking; it was also shown that the presence of C3P with a small amount of the cement can enhance the bioactivity and develop more resistance strength of cement. Moreover, the addition of zinc oxide and bismuth oxide increase the radiopacity of the cement. However, the mechanical strength enhances with the incorporation of the zinc oxide while decrease with bismuth oxide. It was concluded then that there is possibility of combining addition of C3P (10%) and an agent radiopacifiers ZnO/Bi2O3 (15%) with small amounts on C2S to obtain a cement with excellent bioactivity, good mechanical strength and significante radiopacity that makes this material a great candidate as a biomaterial for biomedical use.
摘要: The use of hydroxyapatite coatings is limited by their inferior mechanical properties such as brittle nature, low wear resistance, abrasion, fatigue, and hardness. This ultimately leads to the wear and early rupture of the hydroxyapatite coating on the implant. The main objective of this study is to improve the mechanical properties of hydroxyapatite by using additional reinforcement material such as alumina (Al2O3). The HAp powder has been reinforced with 15wt% Al2O3 and its effect on the properties of HAp coatings has been studied. The HAp and HAp +15 wt% Al2O3 coatings were deposited on AISI 304 L SS substrates using the plasma spraying technique. The morphology of the coatings developed was characterized using SEM/EDX, XRD, and FTIR techniques. The corrosion resistance studies have been performed on uncoated and coated samples and found that HAp coated samples show superior resistance against corrosion (ICorr = 0.538 μA) than uncoated (ICorr = 3.550 μA) and HAp+15 wt% Al2O3 coated (ICorr = 1.440 μA) samples when electrochemical corrosion studies were performed in Ringer’s solution. Surface roughness and microhardness were found to increase with the addition of Al2O3. Crystallinity (%) of the HAp coatings and HAp+15 wt% Al2O3 coatings increases after the corrosion testing.
摘要: Infections total hip arthroplasty (THA) are common and can lead to serious complications for patients. Newly developed antibiotic spacers successfully eradicated infection in more than 90 percent of patients. However, the low mechanical strength of the orthopedic cement can be a serious handicap for the success of the surgical operation. The reinforcement of cement spacers with high strength materials can improve the efficiency of this type of surgery. In this study, the three-dimensional finite element method (FEM) is coupled with the experimental design method (EDM) to optimize the geometrical and mechanical properties of the reinforcement that can be applied to cements spacers. The obtained results show that the full stem reinforcement in bio-ceramic with a thickness of 8.2 mm can represent the optimal model to ensure good mechanical resistance of the cement spacer.
摘要: The success in the chewing process depends on the performance of the tooth used. Actually, taking care of the tooth and improving its performance can change our life. Therefore, the treatment process of the teeth has become more necessary in the life of a dental patient. Nowadays, a post plays an important vital role in this process. In the present work, analysis of the effect of the post material on the performances of the components of endodontically treated teeth (ETT) was carried out through the finite element analysis (FEA). The effects of post material on the von Mises stress component (Svon), shear stress, and displacement component (Usum) occurred on the all components of ETT were investigated. After that, the determination of the optimum material for an endodontic prefabricated post (EPP) was investigated through the sub-problem approximation method.
摘要: Autologous Chondrocyte Implantation (ACI) has been established for years to treat cartilage defect. Application of tissue engineering has advantages over ACI as tissue engineering requires simpler procedures without leaving morbidity at the donor site. Decellularized bovine cartilage scaffold and hypoxic stem cell differentiation were used in this in vitro experimental study. Comparative test was done between three study groups using bone marrow mesenchymal stem cells treated in three different conditions: growth factor-rich chondrogenic medium, scaffold without growth factor, and combination of both. Each group was given two oxygen tension conditions of normoxia and hypoxic within phase of stem cell differentiation. Immunohistochemical examinations on SOX9, RUNX2, and collagen type II were done for evaluation. After 5-week treatment, the result showed that the highest expression SOX9 and collagen type II were found within the group that used the combination of both scaffold and chondrogenic medium in hypoxic condition. Collagen type II expression in scaffold without additional growth factor showed no statistically significant difference compared with the combination group in hypoxic condition. Cartilage tissue engineering has proven its effectiveness for cartilage regeneration. Decellularized biomaterial scaffold limited the use of growth factor resulting in better cost and resource efficiency.
摘要: Experimental reproduction of duodeno-gastric reflux was performed among Wistar line 28 rats, which were injected with 50 % solution of medical bile by intragastric way. Morphological study had been shown significant structural changes in the gingival tissues, mucous membrane of an esophagus, stomach and duodenum. In the epithelial layer of gingiva and esophagus was observed numerous infringements in a process of differentiation cells, in the stroma was shown phenomena of fibrosis in a papillary layer, microcirculation disorders. In the gastric mucosa had been found out multiple erosions, the glandular cells were increased. It was demonstrated vacuolization of the basal and thorn layers of the stomach epithelium. In the stroma defined phenomena of fibrosis and a dense lymphocyte infiltration with eosinophils. In the duodenum was determined desquamation of a glandular epithelium, superficial erosions of the villi, lympho–histio–plasmocytosis infiltration in a stroma, microvascular disorders. The given experiment demonstrates a role of functional disorders in the pathogenesis of combined pathology in the upper gastrointestinal tract.
摘要: The following study is investigating the different GyrB mutations associated with Escherichia coli clinical isolates. The study interrogates part of the ATPase binding site (a.a 132-199) as it covers most of the naturally occurring mutations in GyrB. The following results were obtained: for Arg-136 two isolates had mutations, the first is isolate-1 (Ala-136), and the second is isolate-5 (Cys-136). Gly-164 had no changes for all tested isolates. For Thr-165 only isolate-3 had a change to Ser-165. Accuracy of sequence translation was checked by sequencing both CFT073 and MG1655. The current study presents novel mutations in the GyrB24 subdomain of the gyrase enzyme. These new mutations showed normal enzyme activity (no reduction in ATPase functions) indicating that they might be a result of GyrB interaction with ATP analog molecules rather than antibacterial agents such as coumarins. Furthermore, our findings are supporting the idea that mutations in the GyrB24 would require synchronization with the efflux pumps to maintain antibiotic resistance against coumarins.
摘要: Heart monitoring kits are only available for bedridden patients and the traditional heart monitoring kits have many wires that are obstacle patients’ mobility. Most of the existing heart monitoring kits can not detect heart diseases. Thus, the current study proposed a wireless heart monitoring kit to monitor patients with a heart abnormality. The proposed kit can detect and classify four arrhythmia types as well as normal ECG with high accuracy. The design and development of the wireless heart abnormality monitoring kit (WHAMK) in this research were divided into three stages. These stages are the development of an arrhythmias detection and classification method using artificial intelligence approach, design and implementation of the kit hardware, and design and coding of the kit software. Arrhythmias classification approach is divided into four stages, namely obtaining the electrocardiograph (ECG) signals, preprocessing, features extraction and classification. The features extraction method are based on statistical features. The library support vector machine (LIBSVM) was used to classify the ECG signals. The hardware of the kit is divided into two parts, namely ECG body sensor (EBS), and processing and displaying unit (PDU). EBS working on acquiring the ECG signal from patient's body. PDU working on processing the collected ECG signal, plotting it and detecting the arrhythmias. Arrhythmias classification approach was developed by using statistical features and LIBSVM. They were implemented in the software of the kit to enable it to detect the arrhythmias in the real-time and fully automatically. The kit can detect and classify four arrhythmia types as well as normal sinus rhythm (NSR). These types of arrhythmia are premature atrial contraction (PAC), premature ventricles contraction (PVC), Bradycardia and Tachycardia. The proposed kit gave a good accuracy for detecting and classifying Arrhythmia with the overall accuracy of 96.2%.