Design of wireless inductive power receiver circuit in artificial subretinal chip

A scheme of inductive wireless receiver circuit is put forward, according to special requirement of inductive wireless power supply in artificial subretinal prosthesis circuit. The proposed receiver circuit can be divided into CMOS rectifier, regulator and self-biasing circuit. The CMOS rectifier is used to provide power supply for regulator and self-biasing circuit. The self-biasing circuit furnishes the regulator with bias voltage and bias current which is independent from power supply. The proposed receiver circuit is designed by Cadence tool and Chartered 0.35 μm CMOS device model, and oscillator in artificial subretinal chip is used as the proposed receiver circuit’s load. The results show that the proposed receiver circuit can provide load capacity of 3.3 V and >1 mA,with a layout size of 62 μm×195 μm.     

病毒的锌指蛋白在病毒感染中的作用

锌指（zinc fingers,ZF）结构是一种广泛存在于动植物、微生物包括许多病毒中的蛋白结构,肽链中氨基酸残基的特征基团与Zn²⁺结合从而稳定形成一种很短的、可自我折叠成“手指”形状的多肽空间构型。具有ZF结构的蛋白被称为锌指蛋白（zinc-finger protein,ZNF）,研究发现,部分病毒可以编码具有ZF结构的蛋白且该蛋白会影响到病毒的复制、成熟病毒粒子的包装释放、调节激活病毒转录和裂解性感染及协助病毒的先天免疫逃逸等。本文就目前病毒的ZNF在病毒感染过程中发挥作用的研究进展作一综述,为ZNF的深入研究及以ZNF为靶位点的抗病毒药物研制提供参考。     

单自由度平面六杆手指机构解域综合方法

为适应机器人手指多用途、多尺寸的设计要求,提出一种基于单自由度平面六杆机构解域的手指机构设计综合方法。根据平面六杆机构4个给定的运动位置可得到无穷多机构解,将这些机构解表示在一个平面域上,该域称为解域。本文给定平面六杆机构的4个运动位置,限制待求铰链点的坐标范围,通过给出的铰链点曲线求解方法,得到铰链点解曲线和可行段,对可行段进行分段,得到解域,在此基础上,引入力传递性能指标K,限定其范围,对解域进行进一步的筛选,得到新的可行解域,并得到K在解域上的分布规律,最终可在新解域中选择满足全部条件的机构作为机构解。K值的引入使得所得的机构具有较好的力学性能。解域上的每一点均为满足要求的平面六杆机构,可根据设计的目的(如仿生手指、康复手指等)选择不同的机构进行手指的设计。从新可行解域中选择一个机构设计手指样机,该样机证明了所提出方法的正确性和有效性。     

兴安圆柏嫩枝插穗生根相关内源激素特征分析

为了提高兴安圆柏扦插生根率,探讨兴安圆柏的扦插生根机理,以改进的HPLC法测定了兴安圆柏嫩枝插穗生根过程中4种内源激素的含量变化。结果表明,外源激素处理促进了插穗内IAA合成,显著提高了插穗内IAA含量、IAA/ABA值,ABA含量变化不明显;低浓度的ZT促进生根,插穗生根过程中ZT含量较低,NAA处理使ZT含量比对照显著降低;外施激素降低了生根初期插穗内GA含量,促进了愈伤组织和根原基形成,提高了不定根形成期插穗内GA含量,有利于不定根生长。     

Finger gesture detection and its application to real-time control of prosthetic finger movements

A DSP-based experimental system with real-time finger joint angle detection and prosthetic finger control is designed here. The prototype system is mainly composed of four parts: real-time finger posture detection, joint angle analysis, control pulse encode, and underactuated prosthetic hand with three individually active fingers, i.e. thumb, index finger and middle finger. The real-time finger joint movement is detected by acceleration sensor ADXL330, and the microprocessor DSPTMS320F2812 is used to collect the output of acceleration sensor and calculate angle changes of the finger joint instantaneously. Then, the angle changes are encoded to PWM pulse sequence to control the stepper motor, which drove the rotation of prosthetic finger joint. Preliminary tests are given to multi-finger motion detection and real-time prosthetic finger control, respectively. The experimental results show that the acceleration sensor ADXL330 can be used to reliably detect the gesture of finger movements, it can effectively drive flexion movement and extension movement of prosthetic finger, and the grip action can be completed with the coordination of thumb, index finger, and middle finger.     

Magnetic resonance imaging susceptibility artifact due to pigmented intraorbital silicone prosthesis

Magnetic resonance imaging (MRI) findings of two cases with intracranial disease and pigmented intraorbital prosthetics are presented. A brown prosthetic (Case 1) caused a significant magnetic susceptibility artifact, which necessitated removal to properly image the brain. The artifact observed on MRI images is likely due to ferromagnetic pigments used for coloring. A black prosthetic (Case 2) caused no imaging artifact. The carbon‐based pigments used to color the black prosthetic implant do not appear to cause imaging artifact. The pigments currently used to color the brown pigmented orbital prostheses cause significant magnetic susceptibility artifact and may require removal to evaluate the brain and surrounding structures completely.     

ZFP580, a novel transcription factor,is involved in cardioprotection of hypoxic preconditioning against hypoxia-reoxygenation injury in myocardial cells

AIM：To elucidate whether ZFP580 is involved in the cardioprotective effects of hypoxic preconditioning (HPC) against hypoxia-reoxygenation (H/R) injury in H9c2 myocardial cells. METHODS：Rat heart-derived H9c2 cells were cultured in DMEM. H/R was induced by incubation under ischemic hypoxia for 3 h and reoxygenation for 2 h. HPC was induced by exposing the H9c2 cells to 10 min of hypoxia and 20 min of reoxygenation for 3 cycles before H/R treatment. MTT staining and LDH leakage detection were used to evaluate the effects of HPC. Western blotting was used to detect the protein levels of ZFP580, phosphorylated ERK1/2 and cleaved caspased-3. The effects of ZFP580 overexpre-ssion or knockdown on H/R induced apoptosis were determined. RESULTS：The results of MTT staining and LDH leakage detection showed evidence of HPC cytoprotection against H/R-induced cell death in H9c2 cells. ZFP580 protein level and ERK1/2 phosphorylation were significantly increased in the HPC group compared with control group and H/R group. PD98059, an inhibitor of ERK1/2 phosphorylation, significantly suppressed the HPC-induced up-regulation of ZFP580 protein expression. ZFP580 overexpression significantly inhibited apoptosis and caspase-3 activation in H9c2 cells. CONCLUSION：HPC exhibits cytoprotection against H/R and leads to high level of ZFP580 protein in H9c2 cells. ZFP580 is regulated by ERK1/2 activation and mediates the anti-apoptotic effect of the ERK1/2 signaling pathway in HPC cytoprotection.     

Cohort study examining long‐term respiratory health,career duration and racing performance in racehorses that undergo left‐sided prosthetic laryngoplasty and ventriculocordectomy surgery for treatment of left‐sided laryngeal hemiplegia

Reasons for performing study: The risk of respiratory conditions, such as inflammatory airway disease (IAD) and exercise‐induced pulmonary haemorrhage (EIPH), are thought to be higher in racehorses that undergo prosthetic laryngoplasty with ventriculocordectomy (PLVC) surgery to treat left‐sided laryngeal hemiplegia (LLH) than in racehorses with normal laryngeal function. However, this has not been investigated formally owing to the difficulty of obtaining reliable follow‐up data. Objectives: To determine the incidence of respiratory conditions (IAD and EIPH), duration of racing career, number of starts and number of starts for which stakes money was earned in racehorses that had undergone PLVC surgery to treat LLH, compared with racehorses that did not have LLH or undergo any laryngeal surgery. Methods: A retrospective cohort study design was used, with surgical, clinical and race data of Thoroughbred racehorses obtained from the time of importation until retirement. The surgical cohort consisted of racehorses that had undergone PLVC for LLH and met specific inclusion criteria. Every surgical case was matched, according to trainer, year of import into Hong Kong and pre‐import international handicap rating, to 2 unexposed racehorses. Results: Respiratory conditions, such as excessive tracheal mucus and epistaxis due to severe EIPH, were significantly increased in the surgical cohort, compared with the matched unexposed cohort (P values <0.001 and <0.004, respectively). Racing career duration in the surgical cohort was significantly shorter than in the unexposed cohort, which was primarily due to retirement because of epistaxis. The number of race starts was fewer in the surgical than in the unexposed cohort after surgery/matching, but the number of starts for which stakes money was earned was not significantly different. Conclusions and potential relevance: Owners and trainers should be advised that racehorses with LLH that undergo PLVC surgery are at an increased risk of respiratory conditions (IAD and severe EIPH), which is likely to shorten their racing career compared to racehorses with normal laryngeal function. Racing performance in terms of race starts was significantly less in racehorses that had undergone PLVC surgery; however, the number of starts for which stakes money was earned was similar to those racehorses that were unexposed.