A Wireless Power Transfer System Based on a Hybrid Transmitting Coil for Targeted Therapy Microrobots in the Intestine

Ding Han,Guozheng Yan,Zhiwu Wang,Pingping Jiang,Lin Yan 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.6

A wireless power transfer system for targeted therapy microrobots has been received more attention recently. However, it usually fails to work due to weak coupling caused by misalignment in position and angle between the transmitting coil and the receiving coil. It will not be tolerated even if it occurs at certain angles. To address this issue, a three-dimensional hybrid transmitting coil, combining a fixed Helmholtz coil pair and an adjustable curved rectangular coil pair, is proposed. Based on the novel structure, the proposed hybrid transmitting coil could produce a three-dimensional magnetic field, realizing well coupled with the receiving coil embedded on the microrobot at any posture. To verify the efficiency and practical applicability of the transmitting coil proposed in this paper, we build the coil model via both analytical calculation and simulation analysis. Finally, the designed hybrid transmitting coil is also implemented in the wireless power transfer system with a receiving coil. The magnetic field distribution indicates that a large and uniform magnetic field could be obtained. The experimental results demonstrate that in the central zone of the transmitting coil, 300 × 200 mm, the magnetic field distribution is uniform, which can meet the requirements of the microrobot system working area. And the maximum output efficiency and power can be reached at 5% and 1001 mW, respectively. What's more, the proposed hybrid transmitting coil has solved the weak coupling problem due to misalignment in position and angle with which the electromagnetic energy decays quickly.

Reaction of O,S-Acetals and Phosphites in the Presence of Lewis Acids : Chemoselectivity in the Cleavage of the Acetals

Han, Ding-Il,Kim, Dae-Young,Oh, Dong-Young Korean Chemical Society 1989 Bulletin of the Korean Chemical Society Vol.10 No.3

Excessive mechanical strain accelerates intervertebral disc degeneration by disrupting intrinsic circadian rhythm

Ding Sheng-Long,Zhang Tai-Wei,Zhang Qi-Chen,Ding Wang,Li Ze-Fang,Han Guan-Jie,Bai Jin-Song,Li Xi-Lei,Dong Jian,Wang Hui-Ren,Jiang Li-Bo 생화학분자생물학회 2021 Experimental and molecular medicine Vol.53 No.-

Night shift workers with disordered rhythmic mechanical loading are more prone to intervertebral disc degeneration (IDD). Our results showed that circadian rhythm (CR) was dampened in degenerated and aged NP cells. Long-term environmental CR disruption promoted IDD in rats. Excessive mechanical strain disrupted the CR and inhibited the expression of core clock proteins. The inhibitory effect of mechanical loading on the expression of extracellular matrix genes could be reversed by BMAL1 overexpression in NP cells. The Rho/ROCK pathway was demonstrated to mediate the effect of mechanical stimulation on CR. Prolonged mechanical loading for 12 months affected intrinsic CR genes and induced IDD in a model of upright posture in a normal environment. Unexpectedly, mechanical loading further accelerated the IDD in an Light-Dark (LD) cycle-disrupted environment. These results indicated that intrinsic CR disruption might be a mechanism involved in overloading-induced IDD and a potential drug target for night shift workers.

Preliminary Study on a Three-coil Wireless Power Transfer System for Endoscope Micro-robot of Intestinal Diagnosis: Design, Optimization and Validation

Han Ding,Yan Guozheng,Kuang Shuai,Wang Wei,Zhao Kai 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.4

A wireless power transfer (WPT) system based on inductive resonant coupling makes it possible for endoscope micro robot (EMR) to explore intestine noninvasively. However, due to the increased demand for energy in such micro robot system, such as autonomous movement and drug delivery, the small receiving coil (Φ 15 mm × 13 mm) embedded in limited space on micro robot could not supply enough power as expected. To improve the power supply issue, this article proposes a threecoil WPT system for EMRs system. Based on the refl ected impedance theory, the receiving end of three-coil WPT system is analyzed. Then, according to maximum power transfer principle, parameters relative to performance of WPT system have been optimized through simulation. After that, some bench tests are constructed. A good match is found between analysis results and experimental data. By comparing the three-coil PTW and two-coil WPT systems, it has verifi ed that the transmission effi ciency can be increased signifi cantly to 11.2% by optimized three-coil WPT system and the power dissipation of receiving end could be reduced greatly when the micro robot is under a high power consumption, which is more suitable for endoscope micro robot system with limited space.

Generalized Numerical Differentiation Method for Stability Calculation of Periodic Delayed Differential Equation: Application for Variable Pitch Cutter in Milling

Ding Chen,XiaoJian Zhang,Han Ding 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.11

This paper proposes a generalized numerical differentiation method for stability prediction of the non-autonomous delayed differential equations (DDEs) with periodic coefficients and discrete delays. Firstly, the periodic DDE is described in statespace form and the period of a system is equally discretized. Then, the discrete first derivatives versus time are approximated by a linear combination of the state function values at multiple neighboring sampling grid points based on the finite-difference formulas. Such that, the original DDE is approximated as a series of algebraic equations and the Floquet transition matrix can be constructed on one period. At last, the system stability is determined according to the Floquet theory by checking the eigenvalues. The delayed damped Mathieu equation is regarded as a typical case to verify the effectiveness and efficiency of the presented method. The stability diagrams and rate of convergence are computed in comparison with those via the benchmark algorithm (the semi-discretization method). As an application, the presented method is used to predict the stability of milling with variable pitch cutter, and the computational result agrees well with the experimentally verified example

Ginsenoside Rg1 alleviates A deposition by inhibiting NADPH oxidase 2 activation in APP/PS1 mice

Han Zhang,Yong Su,Zhenghao Sun,Ming Chen,Yuli Han,Yan Li,Xianan Dong,Shixin Ding,Zhirui Fang,Weiping Li,Weizu Li 고려인삼학회 2021 Journal of Ginseng Research Vol.45 No.6

Background: Ginsenoside Rg1 (Rg1), an active ingredient in ginseng, may be a potential agent for thetreatment of Alzheimer’s disease (AD). However, the protective effect of Rg1 on neurodegeneration in ADand its mechanism of action are still incompletely understood. Methods: Wild type (WT) and APP/PS1 AD mice, from 6 to 9 months old, were used in the experiment. The open field test (OFT) and Morris water maze (MWM) were used to detect behavioral changes. Neuronal damage was assessed by hematoxylin and eosin (H&E) and Nissl staining. Immunofluorescence,western blotting, and quantitative real-time polymerase chain reaction (q-PCR) were used toexamine postsynaptic density 95 (PSD95) expression, amyloid beta (Ab) deposition, Tau and phosphorylatedTau (p-Tau) expression, reactive oxygen species (ROS) production, and NAPDH oxidase 2(NOX2) expression. Results: Rg1 treatment for 12 weeks significantly ameliorated cognitive impairments and neuronaldamage and decreased the p-Tau level, amyloid precursor protein (APP) expression, and Ab generation inAPP/PS1 mice. Meanwhile, Rg1 treatment significantly decreased the ROS level and NOX2 expression inthe hippocampus and cortex of APP/PS1 mice. Conclusions: Rg1 alleviates cognitive impairments, neuronal damage, and reduce Ab deposition byinhibiting NOX2 activation in APP/PS1 mice.

Cyclosporin A and sanglifehrin A enhance chemotherapeutic effect of cisplatin in C6 glioma cells

Han, Xuezhe,Yoon, Sung H,Ding, Yan,Choi, Tae G,Choi, Won J,Kim, Yun H,Kim, Young-Joo,Huh, Young-Buhm,Ha, Joohun,Kim, Sung S Spandidos Publications 2010 ONCOLOGY REPORTS Vol.23 No.4

<P>Glioma is the most common type of brain tumors in adults, and treatment of high-grade gliomas is still palliative. Studies to date have revealed only modest effect in attenuating growth of these tumors with single agent therapy, but combination treatment appears to be more effective. Cyclophilin A (CypA), a target of immunosuppressive drugs cyclosporin A (CsA) and sanglifehrin A (SFA), is an intracellular protein that has peptidyl-prolyl cis-trans isomerase (PPIase) enzymatic activity. Previously, we showed that overexpressed CypA induced chemoresistance in cancer cells. Here we provide evidence that combination of cisplatin with either CsA or SFA synergistically enhances apoptotic cell death in C6 glioma cells, compared with single agent treatment. Enhanced apoptotic cell death is a result of an increase in ROS generation and a decrease in intracellular glutathione levels. Consistently, CypA knockdown by siRNA also enhances cisplatin-induced apoptosis. Immunohistochemical analysis showed increased expression of CypA in human glioblastoma multiforme, but not in normal human astrocytes. CypA was also shown to be up-regulated in C6 glioma cells during hypoxia. In conclusion, CsA or SFA in combination with cisplatin synergistically enhances cisplatin-induced apoptosis in C6 glioma cells via inhibition of PPIase activity of CypA, indicating that development of new drugs that selectively inhibit the CypA PPIase activity without immune suppression may facilitate alleviation of chemoresistance in treatment of high-grade glioma.</P>

Insight into the precursor nanofibers on the flexibility of La₂O₃-ZrO₂ nanofibrous membranes

Han, Weidong,Ding, Bin,Park, Mira,Cui, Fuhai,Chae, Su-Hyeong,Kim, Hak-Yong De Gruyter 2017 E-Polymers Vol.17 No.3

<P><B>Abstract</B></P><P>Poly(vinyl pyrrolidone) (PVP)/La<SUP>3+</SUP>/Zr<SUP>4+</SUP>precursor nanofibrous membranes (LZPNM) with various Zr contents were synthesized via a simple electrospinning method. By controlling the Zr incorporation, the tensile properties of precursor membranes dramatically change from 0.77 to 1.73 MPa. Meanwhile, the average diameters of precursor nanofibers increase with the increase of Zr contents (from 283 to 535 nm). In addition, flexible La<SUB>2</SUB>O<SUB>3</SUB>-ZrO<SUB>2</SUB>nanofibrous membranes (LZNM) were obtained by calcination of corresponding precursor membranes. Furthermore, the structures and morphologies of the precursor membranes were investigated using X-ray powder diffraction analysis (XRD) and field-emission scanning electron microscopy (FE-SEM). The surface functional groups and thermal properties of the precursor membranes were measured via Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA).</P>

Crossed Andreev reflection in a quantum dot coupled to a topological superconducting single-stranded DNA

Han-Zhao Tang,Guan-Jun Ding,Xue-Wen Guo 한국물리학회 2020 Current Applied Physics Vol.20 No.11

We investigate the crossed Andreev reflection (CAR) through a quantum dot (QD) coupled to topological superconducting single-stranded DNA (ssDNA). It is found that the topological nontrivial states appear in the QD due to leakage of the Majorana zero mode. Majorana zero mode can be identified by measuring the CAR. This device can be used as a Majorana zero mode detector that relies on the system parameters, such as the spin orbit coupling, the twist angle, molecular length. A high efficiency Cooper pair splitter can be realized by regulating the magnitude and direction of the gate voltage. In additions, the signature of CAR is robust against the Coulomb blockade and the disorder induced by distinct amino acids. This work provides an alternative method for detection of Majorana zero mode in ssDNA.

Solid-phase synthesis of perovskite using spent SCR catalyst and calcium carbonate and its application as ceramic opacifier

Han Zhang,Jianmeng Zhang,Hao Ding,Yangzi Li,Sijia Sun,Weihua Ao,Yu Liang 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.114 No.-

In this study, the synthetic perovskite powder (SPP) was produced by solid-phase method using S-SCRand calcium carbonate (CaCO3), and its structure, morphology, and application as ceramic opacifier werestudied. The results show that SPP with a single perovskite phase can be obtained by grinding and calciningraw materials. Adding SPP as opacifier of sanitary ceramics for firing, a white ceramic glaze withexcellent opacity was obtained. Among the glaze chromaticity values, L* is 93.09, a* is 0.76 and b* is4.98. The opacity of the glaze is stronger than that of the glaze using ZrSiO4 and TiO2 as opacifiers, andthe whiteness of the glaze is significantly greater than that of glaze with TiO2. The ceramic glaze layerusing SPP is mainly composed of glass phase, titanite and quartz, of which titanite is the opacified phase. Importantly, TiO2 is pre-combined into perovskite to make it unable to freely and avoid its own hightemperaturephase transition reaction, which is the mechanism to inhibit the yellowing of glaze surfacecaused by direct use of TiO2. This study can play a positive role in improving the utilization value of S-SCRand eliminating the yellowing of ceramic glazes using TiO2 as opacifier.