用考究的眼光看“器材”——小班化体育器材细节处理

在当前小班化教育趋势下，在体育教学小班化研究道路上，我们要用比以往更加考究的眼光来看“器材”，多角度多视野的看待体育器材的细节，将视野拉回到“小班”。这样对于体育器材的细节的把握会要更加细致与准确。

Optimization Algorithm for Operation Comfortability of Master Manipulator of Minimally Invasive Surgery Robot

To evaluate the operation comfortability in the master-slave robotic minimally invasive surgery(MIS), an optimal function was built with two operation comfortability decided indices, i.e., the center distance and volume contact ratio. Two verifying experiments on Phantom Desktop and Micro Hand S were conducted. Experimental results show that the operation effect at the optimal relative location is better than that at the random location, which means that the optimal function constructed in this paper is effective in optimizing the operation comfortability.

Postoperative sequential chemotherapy and radiotherapy for locally advanced gastric cancer

Objective The aim of the study was to evaluate the role of postoperative sequential chemotherapy and radiotherapy in patients with locally advanced gastric cancer.Methods From January 2003 to December 2010, 146 gastric cancer patients at our institution(Department of Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China) received postoperative sequential chemotherapy and radiotherapy after radical surgery. Radiotherapy was administered as a dose of 4500 cGy in 25 fractions. For patients with positive margins, the dose was raised to 5040 cGy in 28 fractions. Three cycles of m FOLFOX or PF(cisplatin, 5-fluorouracil) chemotherapy regimen were applied before and after radiotherapy. Three-and 5-year survival rates were analyzed; any adverse effects with respect to hematology, hepatic and renal function, or the gastrointestinal tract that occurred during the treatment were evaluated.Results This cohort consisted of non-metastatic patients: 104 men and 42 women with a median age of 51.0 years. The full course of sequential chemotherapy and radiotherapy(4500–5040 cGy) was completed by 129 patients(88.4%). Seventeen regional relapses(9.8%) and 46 distant relapses(23.8%) were recorded. Fifty patients(34.2%) died during follow-up. The 3-and 5-year overall survival rates(OS) were 60% and 54%, and disease-free survival rates(DFS) were 53% and 47%, respectively. There were no significant differences in survival rate with respect to age, sex, histopathology, N stage, site of the tumor, or margin status. Multivariate analysis showed that only the depth of tumor invasion(T stage) was an independent prognostic factor for OS(P = 0.009) and DFS(P = 0.006). The rates of grades 3 and 4 neutropenia and vomiting were 9.6% and 3.4%, respectively, during the treatment.Conclusion Postoperative sequential chemotherapy with an m FOLFOX or PF regimen and radiotherapy were found to be an effective means of treating advanced gastric cancer patients with T3–T4 disease. The adverse effects of this treatment were tolerable.

New self-calibration approach to space robots based on hand-eye vision

To overcome the influence of on-orbit extreme temperature environment on the tool pose(position and orientation) accuracy of a space robot,a new self-calibration method based on a measurement camera(hand-eye vision) attached to its end-effector was presented.Using the relative pose errors between the two adjacent calibration positions of the space robot,the cost function of the calibration was built,which was different from the conventional calibration method.The particle swarm optimization algorithm(PSO) was used to optimize the function to realize the geometrical parameter identification of the space robot.The above calibration method was carried out through self-calibration simulation of a six-DOF space robot whose end-effector was equipped with hand-eye vision.The results showed that after calibration there was a significant improvement of tool pose accuracy in a set of independent reference positions,which verified the feasibility of the method.At the same time,because it was unnecessary for this method to know the transformation matrix from the robot base to the calibration plate,it reduced the complexity of calibration model and shortened the error propagation chain,which benefited to improve the calibration accuracy.

ROBOTIC PASSIVE COMPLIANT WRIST AND ITS OPTIMAL DESIGN

Based on the mechanism of passive compliant assembly, geometric- force models of the assembly are presented, and the stiffness matrix of the laminated circular elastic element is set up. The optimum method of RCC wrist is compiled by way of two ohases, respectively.

Characteristics and outcomes of acute upper gastrointestinal bleeding after therapeutic endoscopy in the elderly

AIM: To characterize the effects of age on clinical presentations and endoscopic diagnoses and to determine outcomes after endoscopic therapy among patients aged ≥ 65 years admitted for acute upper gastrointestinal bleeding (UGIB) compared with those aged < 65 years. METHODS: Medical records and an endoscopy data-base of 526 consecutive patients with overt UGIB admitted during 2007-2009 were reviewed. The initial presentations and clinical course within 30 d after endoscopy were obtained. RESULTS: A total of 235 patients aged ≥ 65 years constituted the elderly population (mean age of 74.2 ± 6.7 years, 63% male). Compared to young patients, the elderly patients were more likely to present with melena (53% vs 30%, respectively; P < 0.001), have comorbidities (69% vs 54%, respectively; P < 0.001), and receive antiplatelet agents (39% vs 10%, respectively; P < 0.001). Interestingly, hemodynamic instability was observed less in this group (49% vs 68%, respectively; P < 0.001). Peptic ulcer was the leading cause of UGIB in the elderly patients, followed by varices and gastropathy. The elderly and young patients had a similar clinical course with regard to the utilization of endoscopic therapy, requirement for transfusion, duration of hospital stay, need for surgery [relative risk (RR), 0.31; 95% confidence interval (CI), 0.03-2.75; P = 0.26], rebleeding (RR, 1.44; 95% CI, 0.92-2.25; P = 0.11), and mortality (RR, 1.10; 95% CI, 0.57-2.11; P = 0.77). In Cox's regression analysis, hemodynamic instability at presentation, background of liver cirrhosis or disseminated malignancy, transfusion requirement, and development of rebleeding were significantly associated with 30-d mortality. CONCLUSION: Despite multiple comorbidities and the concomitant use of antiplatelets in the elderly patients, advanced age does not appear to influence adverse outcomes of acute UGIB after therapeutic endoscopy.

Giant pedunculated sarcomatoid hepatocellular carcinoma: a case report

We report a case who was a 74-year-old female with hepatitis B virus （HBV） carrier for more than 30 years. The serum levels of AFP, CEA and CA199 were within normal range. CT scan demonstrated that a huge pedunculated mass of the right hepatic lobe presenting as Iobulated and cystic-solid appearance and heterogeneous density of the solid portion composed of multiple nodules. The patient was performed surgery, and the tumor was removed. Sarcomatoid hepatocallular carcinoma （SHC） was diagnosed by pathological and immunohistochemical test. The patient has been living for 4 months without tumor recurrence, which indicates that pedunculated SHC might have a high probability for resection and acquire better survival.

Development of Five-Finger Multi-DoF Myoelectric Hands with a Power Allocation Mechanism

To be used as five-fingered myoelectric hands in daily living, robotic hands must be lightweight with the size of human hands. In addition, they must possess the DoFs （degrees of freedom） and high grip force similar to those of human hands. Balancing these requirements involves a trade-off; ideal robotic hands have yet to sufficiently satisfy both requirements. Herein, a power allocation mechanism is proposed to improve the grip force without increasing the size or weight of robotic hands by using redundant DoFs during pinching motions. Additionally, this mechanism is applied to an actual five-fingered myoelectric hand, which produces seven types of motions necessary for activities of daily living and realizes a -60% improvement in fingertip force, allowing three fingers to pinch objects exceeding 1 kg.

Design of a novel finger of DLR/HIT dextrous robot hand based on mechatronic integration

With the idea of mechatronic integration,a novel finger of the dextrous robot hand has been designed. The finger with nice envelop has four joints with three DOFs driven by three brushless DC motors with smaller size and more torque. The use of rigid gear head,bevel gears and linkage in the transmission system makes the finger more rigid. Abundant sensors such as joint angle sensors,joint torque sensors and temperature sensors are located in the finger. Integration and modularization are achieved at most by high integration of finger body,driving system,sensors and electronics.

Mechanism Design of Palletizing Robot Based on Translating Cam Principle

Palletizing robot technology has been applied more and more extensively in logistics automation field.But there are some limitations in the current single-arm palletizing robot that it cannot do effective work in the process of moving back to the taking-end and the mechanical arm has so many freedoms that its control system is relatively complex.Based on the translating cam principle,a novel palletizing robot is designed.The horizontal movement of the palletizing mechanical arm is controlled by changeable outer slides,and the vertical movement is controlled by partitioned up-and-down spindles.To improve palletizing efficiency,the single palletizing mechanical arm is changed into multi-arm.Moreover,to improve its kinematic properties,the acceleration operating performance,joint driving force and palletizing trajectory are optimized through the multi-objective delaminating sequence method.According to the optimization results,the 3D model of the multi-arm palletizing robot is built in Pro/E,and the kinematic simulation is made.The simulation results show that the novel mechanism and optimization parameters are rational and feasible.This novel palletizing robot has the advantages of cam mechanism,so it simplifies the driving mode of palletizing movement and can lower the requirements for controlling system.At the same time,it can increase palletizing efficiency further by adding mechanical arms.

Experimental Results Regarding an Anthropomorphic Original Gripper with Two-Finger Tests during Grasping Objects with Varied Shapes

The paper presents theoretical and experimental results on an original anthropomorphic gripping concept. Compared to the existing anthropomorphic grippers, this gripper is very simple, yet it has the advantage of high performance in terms of gripping possibilities and a very low manufacturing cost. Source of inspiration was the human hand, which is able to catch objects by only using two fingers. The analyzed anthropomorphic gripper has two fingers, with two phalanxes each, and is based on a new mechanism with articulated bars. The kinematic analysis performed on the gripping mechanism reveals the optimal displacement in the translational coupling, which was experimentally validated. The gripping possibilities were increased by attaching clamping jaws to each phalanx. The clamping jaws have been attached by means of spherical couplings, thus offering the possibility to catch objects with any type of surface. By carrying out gripping tests with different objects, we underline the importance of a safe use of the two-fingered anthropomorphic grippers in different applications. Due to the innovative mechanical structure, the gripper can insure the minimal gripping conditions, whilst the complexity of the objects that can be gripped make it suitable for the use in robots.

Role of precoating in artificial vessel endothelialization

As the progress of vascular surgery, artificial vessels have become the substitute for large and middle diameter vessels but have not for small diameter ones owing to thrombogenesis and occlusion within a short period of time after being applied. Artificial vessel endothelialization is one of the ideal methods to resolve such issue and has been improved continuously since Herring in 1978 put forward this term in the first time and utilized vascular endothelial cells (ECs) harvested from living animals to perform the test of artificial vessel endothelialization. However, human endothelial cells show little adhesion to the currently available vascular graft materials and some expanded polytetrafluoroethylene (ePTFE) grafts have shown only 10%+/-7% endothelial cell attachment rate (ECA, ie, attachment of ECs when incubated in vitro). Moreover, when the graft is exposed to pulsatile blood flow, a high proportion of cells are washed off from the lumen. Maximum cell loss occurs in the first 30-45 min after exposure to pulsatile flow, with up to 70% of cells lost. After that, a slower exponential loss occurs over the next 24 h. The lack of retention of cells could be partly overcome by sodding, but other techniques, involving engineering the lumen to improve ECA and endothelial cell retention rate (ECR, ie, retention of ECs when the grafts are exposed to pulsatile flow) have been developed. These include shear stress preconditioning, electrostatic charging and, above all, most successfully to date, precoating with EC specific adhesive glues that are mostly found in the extracellular basement membrane of blood vessels. The commonest are chemical coatings, preclotting, chemical bonding, and surface modifications.

Three-dimensional cell culture models for investigating human viruses

Three-dimensional(3D) culture models are physiologically relevant, as they provide reproducible results, experimental flexibility and can be adapted for high-throughput experiments. Moreover,these models bridge the gap between traditional two-dimensional(2D) monolayer cultures and animal models. 3D culture systems have significantly advanced basic cell science and tissue engineering, especially in the fields of cell biology and physiology, stem cell research, regenerative medicine, cancer research, drug discovery, and gene and protein expression studies. In addition,3D models can provide unique insight into bacteriology, virology, parasitology and host-pathogen interactions. This review summarizes and analyzes recent progress in human virological research with 3D cell culture models. We discuss viral growth, replication, proliferation, infection, virus-host interactions and antiviral drugs in 3D culture models.