Abstract: The traditional design method of machine tool column easily leads to material redundancy and it is difficult to achieve the best structural efficiency. A bionic method is proposed, bamboo was used as the biological archetype, to design the column structure of an extra-heavy duty CNC boring and milling machine. The macroscopical and microscopic structural characteristic and the mechanical property of the bamboo are analyzed, and the intrinsic relationship between the microstructure and mechanical properties is obtained. The column is designed as cylindrical structure firstly, and the relationship between the number of transverse ribs and the whole bending deformation is ascertained. The transverse ribs are designed for cylindrical structure .By evolving the cylindrical member, A, B two kinds of bionic column are designed and compared. The specific stiffness of B type structure is increased 10.9% and its overall performance is better than the A. So the B scheme is selected as the final bionic structure of the column.
Abstract: Recently, ionic actuator as a kind of artificial muscle has attracted great attentions according to their remarkable strain under low-voltage stimulation. Here, we investigated a biocompatible ionic polymer actuator, which consists of multi-walled carbon nanotubes (MCNTs) film as the double electrode layer and an electrolyte layer equipped with a chitosan polymer skeleton. As a result, we found it presented various electromechanical properties under the preparation factors of the different additive glycerol (0mL, 2mL, 4mL). The actuators with 2mL glycerol behaved a longer life bending (65 times), which was obviously surpassed by the others. Also, based on strain and stress testing, Young's modulus of the electrolyte presented a decreasing trend. In fact, the improvement was mainly due to the weakened inter-molecular hydrogen and the rotation molecular of the electrolyte film. Results show the additive inside the electrolyte is very effective to improve the performance of artificial muscle.
Abstract: Bone grafting is a surgical procedure that replaces missing bone with material from patient′s own body, an artificial, synthetic, or natural substitute. As natural bone grows, it generally replaces the graft material completely, resulting in a fully integrated region of new bone. The type of bone graft are allograft-based bone graft involves allograft bone, Factor-based bone graft are natural and recombinant growth , cell-based bone grafts, ceramic-based bone graft substitutes, polymer-based bone graft. The aim of study are to explore the influence of variations in the composition of alginate 8wt % , 10wt % , 12wt % to the characterization and the role of compacting pressure variation to the characterization of hydroxyapatite – alginate and to explore the best composition variation of alginate in which provides the best characteristics for application as a bone graft. All of the materials were mixed with a magnetic stirrer into liquid until homogeny, dried with oven with temperature of 50 °C, and then frozen for optimalizing the drying with sublimation method. The variation of Alginate composition were 8%wt, 10%wt, 12%wt, while the variation of compaction were 1 N/m2, 2 N/m2, 3 N/m2. The sample characterization used Fourrier Transform Infra Red (FTIR) test, compressive strength test, and MTT Assay test. Based on morphology assay, the pore sizes from samples with greater compaction force produces an increasingly smaller pore size. The result showed that variation of hydroxyapatite – alginate composition had effect to compressive strength value. The higher percentage composition of alginate, the greater pressure will increase the value of its compressive compaction and strength. The result of cytotoxicity test showed that nine samples were non toxic. In this research, the sample with composition 12% wt alginate and 3 N/ m2 in compaction was the best characteristic according to mechanical aspect.
Abstract: HA and HA+Y2O3 films were prepared by pulsed laser deposition. The microstructure and composition of films were studied by EPMA, XRD, AFM and SEM. In vitro study was performed by immersing the sample in simulate body fluid (SBF) in different days. There are more droplets on films prepared by HA+Y2O3 target than that of HA. And addition of Y2O3 can decrease the size of crystal grains. The XRD results show that the peaks corresponding to HA slightly shift to lower angel which indicates the HA lattice distorting due to addition of Y2O3. The critical load of the films increases from 10.3N to 13N when Y2O3 added. The film prepared by target HA+Y2O3 shows a higher resistance to dissolution and the precipitated grain size is small. New precipitated phases have similar functional groups with the original films.
Abstract: Although effective, chemotherapeutic drugs often cause undesired side-effects. Thus, encapsulating chemotherapeutic drugs into nanoscale drug delivery vehicles (DDVs) has the potential to reduce side effects and promote targeted delivery. By mimicking ABA like block-co-polymer systems, we have developed a new amphiphilic biomimetic co-polymer Boc-Ile-PEG-Ile-Boc which was found to readily self-assemble into nanomicelles within hydrophilic shell structures. To facilitate targeting tumor cells, the nanoassemblies were bound to folate, leading to the formation of core shell like structures (IBP-F). Gold nanoparticles (AuNPs), were then embedded followed by functionalization with a second layer of folate. The final DDV system abbreviated (IBP-F-Au-F) formed a multi-layered nanostructure that was capable of efficiently encapsulating the anti-tumor drug tamoxifen. For comparison, we also examined the efficacy of the IBP-F assemblies as DDVs in the absence of AuNPs and a second folate layer. Release profiles showed an initial burst release, followed by sustained release. The DDVs were found to be biocompatible. Upon encapsulating the DDVs with tamoxifen, cell proliferation was inhibited over a period of 72 hours for both DDVs, while non-cancerous dermal fibroblasts continued to proliferate, thus indicating specific targeting ability of the DDVs. Confocal microscopy studies conducted in the presence of human breast cancer cells, MDA-MDB 231 revealed that the drug loaded assemblies were successfully internalized within the cells. SPR analysis demonstrate that IBP-F-Au-F had a higher affinity for breast cancer cells over non-cancerous keratinocyte cells. Thus, we have developed a new family of DDVs that selectively targets tumor cells.
Abstract: At the children with chronic gastritis and duodenitis was revealed destroyed of morphological - functional property of gums with prevalence of degenerative component, which is manifested by appearance of basal and parabasal cells (0.3%), increasing of intermediate epithelial cells (84.7%), decreasing amount of surface nucleated epithelial cells (11.7%), and nuclear-free dead skin cells (4.3%). Majority of cells was with cytopathology shifts (18.2%), polymorphonuclear leukocytes (92.3%) and lymphocytes (20.5%). The data obtained in the research showed that 23 (21.5%) of samples, taken from children with chronic gastritis and duodenitis revealed cells in the early stages of differentiation, accumulation of leukocytes and fibrin, which demonstrates erosions of the gums in the epithelial layer. Adhesion of epithelial cells with Candida albicans at the children with chronic gastritis and duodenitis indicates about changes functional properties of the epithelial cells, growing on a background of the somatic pathology.
Abstract: The median frequency (MF) and mean power frequency (MPF) have been confirmed as reliable indicators of muscle fatigue during sustained contractions. The purpose of this study was to explore whether single-monitor arm could release muscle fatigue in neck-shoulder region while maintaining a prolonged seated posture viewing computer screen by measuring MF and MPF. Ten male healthy university students volunteered to participate in the test. Surface electromyography of splenius capitis (SC) and trapezius (TR) were recorded. Each subject performed normal text editing tasks or video watching activities for 120 minutes with different monitor arm positions (Fixed, moving downward and moving upward). Results showed that the MPF of SC and TR had significant decreased trend as monitor arm at fixed position. As monitor arm moving upward, the MF and MPF of both muscles decreased significantly with time and the MF showed the lowest decline rate during the entire testing process. No significant shift of MF and MPF were observed as monitor arm moving downward. Findings of this study may have important implications for people who use computer intensively to release neck-shoulder muscle fatigue.
Abstract: This study analyzes the effects of the devices that work at the frequency of 2450 MHz and that release electromagnetic waves on the growth of bacteria. E. Coli bacterial cells are used in this experiment. The bacterial cult is divided into two groups under sterilized conditions. For both groups, the temperature is held constant at 37 Co while the heating effect of the devices working at the frequency of 2450 MHz is minimized. Then, the bacterial cells in the experimental group are exposed to the electromagnetic waves released by the devices working at the frequency of 2450 MHz while the control group is incubated for 8 hours without any exposure to electromagnetic waves. At each hour, samples from the E. Coli bacteria that are exposed to electromagnetic waves and from the control group. After measuring the optical density of the samples, it is found that the electromagnetic waves released by the devices working at the frequency of 2450 MHz have negative effects on the growth of bacteria. So, the effects of the electromagnetic waves released by the devices working at the frequency of 2450 MHz on the growth of the bacteria might be thermal or stress-related. However, there is a need for further physiologic and morphologic studies on this issue. The studies on this issue should be conducted for the public health.
Abstract: Cell segmentation provides an opportunity to reveal object of interest from the background of an image. In the traditional graph cut segmentation approach, the user initiates the segmentation process by selecting pixels for foreground and background. However, one of the problems of traditional graph cut is that it is time consuming, especially on a large dataset. Thus, we propose a fully automatic technique for cell segmentation on graph cut to automate the selection of sample foreground and background pixels. In order to achieve this, a combination of two methods namely Otsu thresholding and kmeans clustering algorithm is explored. The Otsu thresholding and the k-means provides an initial cell segmentation, creating a platform to automatically select sample foreground and background pixels initiating the graph cut segmentation. Experimental results on two public datasets suggest promising results.
Abstract: Neurosurgery navigation system consists of an image workstation, infrared optical positioning device and surgical instrument components. The system can use the patient CT/MRI images to develop preoperative surgical plan, choose the best surgical approach, in surgery it can rely on the three-dimensional patient images and optical locator, avoiding critical organizations and major functional areas, to make surgery smaller incisions, more thorough, more secure. The development consists of the following steps: image group management, displaying three orthogonal plane (transverse, sagittal, coronal), 3D reconstruction, image segmentation, three-dimensional drawing, 3D image space and operative space registration structure and function like image fusion. The main work and contribution of this paper is: 1. three dimensional reconstruction using linear interpolation instead of the bilinear interpolation, improve image clarity; 2. 3D rendering, pixel reconstruction filter using windowing, then directly draw pixels to improve rendering speed; 3. human-computer interaction by reducing the resolution to accelerate and achieve real-time three-dimensional rotation; 4. 3D image space and space operation registration method using landmarks, enhanced registration reliability; 5. with fusion of the function and structure image surgery can be used to avoid important functional areas, reduce the risk of disability.