An Endoscope Manipulating Robot Design Xiaohui, Xie; Xiuan, Zhang; Lining, Sun ...
Journal of physics. Conference series,
06/2019, Letnik:
1213, Številka:
2
Journal Article
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This paper mainly studies a new type of endoscope manipulating robot to replace the nurse or assistant to manipulate and hold the endoscope in surgery. By analyzing the operating environment of ...minimally invasive surgery, the paper presented the basic requirements of the endoscope manipulating mechanism design, and developed a endoscope manipulating system with seven degree of freedom. In order to meet the intraoperative spatially invariant point required by the minimally invasive surgery, a new romote-center-of- motion(RCM) mechanism, parallelogram RCM mechanism, was designed by improving composite parallelogram mechanism. In addition, a wire-driven modular joint with single-degree-of- freedom was also developed, which has been used for the endoscope operating in-out the human body. The motion test of RCM mechanism shows that the robot has good flexibility and can fully meet the design requirements of the endoscope manipulating mechanism.
Radiotherapy is a treatment choice for local control of breast cancer, particularly after the removal of tumor tissues by surgery. However, intrinsic radioresistance of cancer cells limits ...therapeutic efficacy. Here, we determined in breast cancer cells the potential radiosensitizing activity of SM-164, a small molecule compound, that mimics the activity of SMAC, a mitochondrial protein released during apoptosis to activate caspases by inhibiting cellular inhibitor of apoptosis proteins, cIAP-1, and XIAP. We found that SM-164 at nanomolar concentrations promoted degradation of cIAP-1, disrupted the inhibitory binding of XIAP to active caspase-9, and sensitized breast cancer cells to radiation with a sensitization enhancement ratio (SER) of 1.7–1.8. In one line of breast cancer cells resistant to SM-164 as a single agent, SM-164 radiosensitization was mediated by intrinsic apoptosis pathway through activation of caspases-9 and -3. In a line of breast cancer cells sensitive to SM-164 as a single agent, SM-164 radiosensitization was mediated by both extrinsic and intrinsic apoptosis pathways through activation of caspases-9, -8, and -3. Consistently, blockage of caspase activation, through siRNA knockdown or treatment with a pan-caspase inhibitor z-VAD-fmk, inhibited apoptosis and abrogated SM-164 radiosensitization. Our study demonstrates that IAPs are valid radiosensitizing targets in breast cancer cells and SM-164 could be further developed as a novel class of radiosensitizers for the treatment of radioresistant breast cancer.
Immune evasion of cancer cells is mainly due to the impaired transduction of apoptotic signals from immune cells to cancer cells, as well as inhibition of subsequent apoptosis signal cascades within ...the cancer cells. Over the past few decades, the research has focused more on the impaired transduction of the apoptotic signal from immune cells to cancer cells, rather than inhibition of the intracellular signaling pathways. In this study, miR-221 inhibitor was transfected into bladder cancer cell lines 5637, J82 and T24 to repress the expression of miR-221. As a result, the repression of miR-221 on p53 upregulated modulator of apoptosis (PUMA) was abolished, resulting in increased expression of the pro-apoptotic Bax and reduced expression of the anti-apoptotic Bcl-2, which promotes apoptosis of bladder cancer cells. The expression of MMP-2, MMP-9 and VEGF-C were reduced, resulting in reduced invasiveness and infiltration capability of bladder cancer cells, thereby inhibiting the immune evasion of bladder cancer cells.
In this paper, a new arc-surfaced frictional damper (AFD) is proposed and its hysteretic behavior is experimentally studied. Then the device is applied to container crane based on a seesaw mechanism. ...The major advantage of the seesaw damping system is that the long tension cables can be utilized as bracing between the seesaw member and the portal legs to avoid compression and buckling of the cables. A simplified trilinear force-displacement model on the basis of experimental results is adopted to represent the hysteretic behavior of AFD. After that, seismic responses of container crane with and without dampers to four earthquakes are studied using nonlinear dynamic time-history analysis. Besides this system, a diagonal-brace-AFD system is studied for comparison. A method based on the displacement and energy dissipation ratio is proposed to find the optimum slip force for seesaw damping system. Performance of AFD control system is assessed though various parameters including displacement and maximum portal frame drift angle. Results prove a feasible application of AFD control system to absorb large amounts of seismic energy and significantly reduce the structural responses.
A type of space-coiling acoustic metamaterials (AMs) featuring quasi-fractal geometries is proposed, with filling curves based on the construction for recursive substructures of triangles. The ...bandgap properties and the acoustic isolation capabilities of the fractal acoustic metamaterials (FAMs) are evaluated by the dispersion relations and the transmission properties on the subwavelength scale. The effective responses for the FAMs with various fractal levels are clarified based on the transfer matrix method and equivalent medium theory. Besides, the behaviors of the zero-phase-difference transmission arising from density-near-zero and the acoustic focusing are also explored in the FAMs applications. The results show that the FAMs exhibit superior broadband properties, with the maximum percentage of complete bandgaps over 33% across the considered spectrum, and the FAMs with higher fractal level possess greater numbers and lower frequency bands. In addition, the FAMs can enable multiple applications including 180 degrees bending transmission, acoustic cloaking, acoustic tunneling, wave front shaping and point source imaging. This design might contribute new insights for controlling low frequency acoustic waves with broadband and developing multifunctional acoustic devices.
Insulin‐like growth factor‐2 messenger RNA‐binding protein 3 (IGF2BP3) has been reported to contribute to tumorigenesis in several human cancers. However, the biological functions of IGF2BP3 in ...bladder cancer are poorly understood. We investigated the relation between IGF2BP3 expression and prognosis of bladder cancer patients. Cell proliferation, cell cycle and cell apoptosis assays were performed to assess IGF2BP3 functions. The results showed that IGF2BP3 was overexpressed in bladder cancer tissues compared with that in normal bladder tissues, and its higher expression was closely correlated with poor prognosis in bladder cancer patients. Overexpression of IGF2BP3 markedly promoted cell proliferation and cell cycle progression and inhibited cell apoptosis, while knockdown of IGF2BP3 notably suppressed the proliferation, promoted cell apoptosis and induced cell cycle arrest at the G0/G1 phase. Mechanistically, we revealed that IGF2BP3 promotes the activation of the JAK/STAT pathway in bladder cancer cells. Moreover, the JAK/STAT inhibitor dramatically blocked the tumour‐promoting activity of IGF2BP3. Tumour growth in vivo was also suppressed by knocking down of IGF2BP3. Hence, IGF2BP3 facilitated bladder cancer cell proliferation by activating the JAK/STAT signalling pathway. These findings suggest that IGF2BP3 exhibits an oncogenic effect in human bladder cancer progression.
Abstract Background Renal ischemia-reperfusion injury (IRI) is a complex pathophysiologic process involving cell apoptosis and oxidant damages that leads to acute renal failure in both native kidneys ...and renal allografts. Pioglitazone is a novel class of oral antidiabetic agents currently used to treat type 2 diabetes mellitus. Pioglitazone exerts protective effects on acute myocardial ischemia and acute cerebral ischemia. The aim of this study was to investigate the possible beneficial effects of pioglitazone on renal IRI in mice. Methods IRI was induced by bilateral renal ischemia for 45 min followed by reperfusion. Fifty-five healthy male Balb/c mice were randomly assigned to one of the following groups: PBS + IRI, pioglitazone + IRI, PBS + sham IRI, pioglitazone + sham IRI. Kidney function tests, histopathologic examination, renal cell Bcl-2, and Bax expression were determined 24 h after reperfusion. Animals’ survival was examined 7 days after operation. Results Animals pretreated with pioglitazone had lower plasma levels of blood urea nitrogen and creatinine caused by IRI, lower histopathologic scores, and improved survival rates following IRI. Renal cell apoptosis induced by IRI was abrogated in kidneys of mice pretreated by pioglitazone, with an increase in Bcl-2 expression and a decrease in Bax expression. Furthermore, pioglitazone pretreatment protected against lethal renal IRI. Conclusions Peroxisome proliferator–activated receptor activation by pioglitazone exerts protective effects on renal IRI in mice by abrogating renal cell apoptosis. Thus, pioglitazone could be a novel therapeutic tool in renal IRI.
Recent studies have shown the remarkable gender differences in the susceptibility or expression of many diseases. The mechanism underlying the gender differences is unclear. In the present study, we ...evaluated the effects of gender differences and different ischemia time on the renal ischemia-reperfusion injury (IRI). The IRI was induced in the bilateral kidneys of 156 male and 30 female BALB/c mice. Renal function, serum creatinine and blood urea nitrogen, and pathology of the kidneys were examined at 24 hr after IRI. Renal IRI was generated successfully in 182 of 186 mice with a 97.85% success rate. The levels of serum creatinine and blood urea nitrogen were significantly increased in male mice subjected to 30 min, 35 min, or 45 min of renal ischemia and in female mice subjected to 75 min of renal ischemia, compared to the control group at 24 hr after operation. In males following 35 min or 45 min of ischemia and in females following 75 min of ischemia, typical acute tubular necrosis was found in the areas of corticomedullary junction and the histopathologic scores, which represent the degree of renal tissue injuries, were significantly increased. In view of our data, the kidneys of male are much more susceptible to IRI than those of female. The optimal ischemia time of kidney is 35 - 45 min in males and 75 min in females for generating a stable model of IRI in mice. Investigation of the gender differences might provide a new area for mechanistic study of renal IRI.
This work proposes a design strategy for an acoustic metasurface with the goal of flexibly modulating reflected waveforms. The metasurface unit is composed of a rigid base and a column of rectangular ...partitions arranged in a comb-like configuration. A full 2π phase shift of the reflected waves can be achieved by adjusting the height of these rectangular partitions. The utilization of a particle swarm optimization algorithm determines the specific phase shift of the units along the metasurface. As a pragmatic example, it is shown that the comb-like metasurface offers a superior ability to direct the propagation of reflected sound waves in the desired directions, and experiments are performed to verify this anomalous reflection phenomenon. Furthermore, numerical calculations effectively demonstrate the application of the acoustic ground illusion. This work presents an effective and feasible design scheme for acoustic wave manipulation.
•A particle swarm algorithm is applied to the comb-like metasurface design.•Two applications: anomalous reflection and acoustic ground illusion are explored.•The wavefront tailoring capability of the comb-like metasurface is validated.
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