A systems-level perspective of the biomechanics of the trunk flexion-extension movement: Part II – Fatigued low back conditions

Our companion paper demonstrated the importance of a systems-level perspective on spine biomechanics by showing the effects of lower extremity constraints during simple, trunk flexion-extension motions. This paper explores the impact of trunk muscle fatigue and stress-relaxation of lumbar passive tissues on this systems-level response. Twelve participants performed experimental protocols to achieve lumbar passive tissue stress-relaxation fatigue and lumbar muscle fatigue. Participants performed full range of sagittal-plane trunk flexion-extension under unconstrained stoop movement and pelvic/lower extremity constrained stoop movement. They performed these motions both before and after the fatigue protocols and trunk kinematics and muscle activities in trunk and lower extremity muscles were monitored. Under the condition of passive tissue fatigue, low back muscles and lower extremity muscles revealed significantly increased activation level (21% and 22%, respectively) in the free stoop condition but under the restricted stoop condition, there was no significant effect of the protocol. Under the lumbar muscle fatigue condition, a significant antagonistic and lower extremity activation effect (34% increase in abdominal muscles, 16% increase in lower extremity muscles) was observed in the free stooping condition while these variables were not affected by the protocol under the restricted stooping condition.Relevance to industryFatigue of the lumbar musculature and passive tissues is prevalent in jobs requiring full trunk flexion postures. Developing accurate biomechanical models of spinal stress in these full stooping postures can help in the development of appropriate interventions to reduce the prevalence of back injuries in these jobs.     

Paper-based digital microfluidics

In this paper, a new fabrication method for digital microfluidics is proposed. In which, paper, graphite, and adhesive tape are used as substrate, electrodes, and dielectric layer, respectively. The graphite is sprayed over a template on the paper substrate. Two different water repellants are used as the hydrophobic layer, which replace with expensive materials such as Teflon-AF^®. The paper substrate is low cost, available, and flexible. The proposed device is disposable, and its fabrication procedure is simple, fast, and low cost which allows creation of a new device for each individual experiment. Therefore, problems such as adsorption and dielectric breakdown will not occur in this type of digital microfluidics. This device can perform two types of droplet operations, merging and moving on droplets in volumes of 15–50 μL.     

Robot Finger Using Electro-Conjugate Fluid

Abstract

An electro-conjugate fluid (ECF) is a kind of functional fluid, which produces a jet flow (ECF jet) when subjected to high DC voltage. It is known that a strong ECF jet is generated under a non-uniform electric field (e.g., a field with a pair of needle and ring electrodes (a needle–ring electrode pair)). This study introduces the ECF jet to develop a novel flexible robot finger. First, we propose a concept for a novel robot finger. The robot finger mainly consists of a bending actuator, an ECF tank and ECF jet generators, which could be a micro fluid pressure source of the robot finger. Second, we characterize each component of the robot finger (i.e., the bending actuator and the ECF jet generator). We investigate the influences of electrode parameters on ECF jet generator performance in order to design the finger prototype. Finally we clarify the characteristics of the robot finger. The length, the diameter and the mass of the robot finger are 34.2 mm, 12 mm and 3.8 g, respectively. The robot finger can generate a force of 0.28 N and bend approximately 70°.     

基于生理舌头模型的语音可视化系统

目的 目前针对舌头的语音同步动画技术还未得到广泛的研究。在此背景下,提出了一种基于生理模型的舌头动画合成方法。方法 首先构建了一个精细的、能够在肌肉激励下产生逼真舌头变形的舌头生理模型;其次利用该舌头模型合成了大量的舌头运动样本,并据此通过学习得到一个从肌肉激励到舌头轮廓的转换模型;然后对采集的动态2维舌头轮廓数据进行运动参数估计以得到与音素对应的体素(肌肉激励序列和刚体位移序列);最后将体素按一定的排列方式输入到舌头生理模型进行仿真以生成相应的舌头动画。结果 该系统可以合成听觉效果逼真的语音和视觉效果逼真且与合成语音同步的舌头动画。结论 本文方法可以根据汉语普通话或其他语言的2维舌头轮廓数据构建音素—体素数据库,并据此合成该语言对应的高真实感的3维舌头动画。     

使用线约束运动最小二乘法的视差图像拼接

目的 图像配准是影响拼接质量的关键因素。已有的视差图象拼接方法没有解决匹配特征点对间的错误配准问题,容易引起不自然的拼接痕迹。针对这一问题,提出了使用线约束运动最小二乘法的配准算法,减少图像的配准误差,提高拼接质量。方法 首先,计算目标图像和参考图像的SIFT（scale-invariant feature transform）特征点,应用RANSAC（random sample consensus）方法建立特征点的匹配关系,由此计算目标到参考图像的最佳单应变换。然后,使用线约束运动最小二乘法分别配准两组图像：1）第1组是目标图像和参考图像;2）第2组是经单应变换后的目标图像和参考图像。第1组用逐点仿射变换进行配准,而第2组配准使用了单应变换加上逐点仿射变换。最后,在重叠区域,利用最大流最小割算法寻找最优拼接缝,沿着拼接缝评估两组配准的质量,选取最优的那组进行融合拼接。结果 自拍图库和公开数据集上的大量测试结果表明,本文算法的配准精度超过95%,透视扭曲比例小于17%。与近期拼接方法相比,本文配准算法精度提高3%,拼接结果中透视扭曲现象减少73%。结论 运动最小二乘法可以准确地配准特征点,但可能会扭曲图像中的结构对象。而线约束项则尽量保持结构,阻止扭曲。因此,线约束运动最小二乘法兼顾了图像结构的完整性和匹配特征点的对准精度,基于此配准模型的拼接方法能够有效减少重影和鬼影等人工痕迹,拼接结果真实自然。     

Investigating haptic distance-to-break using linear and nonlinear materials in a simulated minimally invasive surgery task

Accurate detection of mediated haptic information in minimally invasive surgery (MIS) is critical for applying appropriate force magnitudes onto soft tissue with the aim of minimising tissue trauma. Force perception in MIS is a dynamic process, with surgeons’ administration of force into tissue revealing information about the remote surgical site which further informs the surgeons’ haptic interactions. The relationship between applied force and material deformation rate provides biomechanical information specifying the deformation distance remaining until a tissue will fail: which is termed distance-to-break (DTB). The current study demonstrates that observers can detect DTB while deforming simulated tissues and stop before reaching the tissues’ failure points. The design of training simulators, control devices and automated robotic systems for applications outside of MIS is discussed.

Practitioner Summary: In MIS, haptic information is critical for applying appropriate forces onto soft tissue to minimise tissue trauma. Observers used force information to detect how far they could deform a virtual tissue before it would break. The design of training simulators, control devices and automated robotic systems is discussed.     

Improving device-aware Web services and their mobile clients through an aspect-oriented,model-driven approach

ContextMobile devices have become an essential element in our daily lives, even for connecting to the Internet. Consequently, Web services have become extremely important when offering services through the Internet. However, current Web services are very inflexible as regards their invocation from different types of device, especially if we consider the need for them to be adaptable when being invoked from mobile devices.ObjectiveIn this paper, we provide an approach for the creation of flexible Web services which can be invoked transparently from different device types and which return subsequent responses, as well as providing the client’s adaptation as a result of the particular device characteristics and end-user preferences in a completely decoupled way.MethodAspect-Oriented Programming and model-driven development have been used to reduce both the impact of service and client code adaptation for multiple devices as well as to facilitate the developer’s task.ResultsA model-driven methodology can be followed from system models to code, providing the Web service developer with the option of marking which services should be adapted to mobile devices in the UML models, and obtaining the decoupled adaptation code automatically from the models.ConclusionWe can conclude that the approach presented in this paper provides us with the possibility of following the development of mobile-aware Web services in an integrated platform, benefiting from the use of aspect-oriented techniques not only for maintaining device-related code completely decoupled from the main functionality one, but also allowing a modularized non-intrusive adaptation of mobile clients to the specific device characteristics as well as to final user preferences.     

Analysis of sitting comfortability of driver's seat by contact shape

Abstract

In order to evaluate sitting comfort qualitatively, a flexible and very thin sensor was developed to measure the contact shape between a seated man and the seal surface. Each tape has twenty strain guages on it at regular intervals, and the fourteen tape sensors were arranged on the bottom and back surface of the experimental driver's seat. The contact shapes and postures in thirty two male drivers were measured with two types of seal cushion and sitting posture: free and recommended. Sensory evaluation was made for each experimental condition. The results of the interrelation between the characteristics of the surface deformation, the parameters of body build, sitting posture and feeling of comfort shows that the comfort of each morphological fitting does not correspond to one special and single parameter from those physical factors, but is represented by a function with many parameters related to the deformation, posture and body build. By using these relations, a sensory model for the prediction of the sitting comfort was constructed.     

Shoulder and neck muscle activities during typing with articulating forearm support at different heights

Use of forearm support is known to reduce physical stress of computer users, but research about how to properly position the forearm support is insufficient. This study was aimed to determine whether the height of forearm support influences muscular loads during typing. Twenty four subjects performed a typing task with a pair of articulating forearm support at three different heights as well as without any support, while shoulder, neck and forearm muscle activities and posture data were recorded. Typing with the support at resting elbow height produced significantly (p < 0.05) lower shoulder and neck muscle activities than that of no support condition. Typing with the support at heights higher than the resting elbow height produced significantly greater shoulder and neck muscle activities compared to the no support condition. Results suggest that forearm support can help computer users lessen physical stress in typing, but only when the supports are positioned at resting elbow height.

Practitioner Summary: Use of forearm support is known to alleviate physical stress of PC users in computer works such as typing. This experimental study addressed the importance of proper positioning of forearm support by comparing neck and upper extremity muscle activities between conditions with varying heights of forearm support in keyboard typing.     

Letter: Solution‐processed flexible zinc‐tin oxide thin‐film transistors on ultra‐thin polyimide substrates

In this letter, solution‐processed flexible zinc‐tin oxide (Z_0.35T_0.65O_1.7) thin‐film transistors with electrochemically oxidized gate insulators (AlOx:Nd) fabricated on ultra‐thin (30 µm) polyimide substrates are presented. The AlOx:Nd insulators exhibited wonderful stability under bending and excellent insulating properties with low leakage current, high dielectric constant, and high breakdown field. The device exhibited a mobility of 3.9 cm²/V · s after annealing at 300 °C. In addition, the flexible device was able to maintain the electricity performance under various degrees of bending, which was attributed to the ultra‐thin polyimide substrate.     

Medical device on pharmacists' work-related musculoskeletal complaints and burnouts

This study analysed the total number of consumed vials of chemotherapy drugs during the year 2007 to determine workloads, and investigated the effects of using the Spike medical device in contrast to the use of traditional needles on oncology pharmacists' dispensing time, muscle soreness, work-related burnout and fatigue symptoms. Work-related burnout and physiological symptoms were measured using the Copenhagen Burnout Inventory (CBI) and a visual analogue pain scale. The Spike device significantly reduced the time spent in drawing up fluorouracil (39.46 ± 9.43 s vs. 57.13 ± 13.47 s) or cisplatin (29.65 ± 11.22 s vs. 60.93 ± 20.54 s) compared with traditional needles (P < 0.001). The CBI burnout score improved significantly with the Spike device (53.21 ± 8.58 vs. 73.21 ± 5.42; P = 0.007) because finger and palm muscle soreness complaints and subjective fatigue symptoms for eye tiredness and shoulder–wrist pain were significantly reduced (P < 0.05).

Practitioner Summary

The pharmacist needs to exert hand strength to counter the vial back-suction pressure to draw out the medical liquid, and confirm the volume during the drawing antineoplastic drug procedure. This study aimed to determine the effects of using a medical device, instead of a needle, on pharmacists' work-related musculoskeletal complaints and burnouts.     

Development of a color‐tunable polychromatic organic‐light‐emitting‐diode device for roll‐to‐roll manufacturing

A flexible vertically stacked flexible polychromatic color‐tunable OLED has been developed by means of low resistive intermediate electrode technology. The polychromatic OLED has a capability to show 16 million colors with 105% National Television Committee Standard (NTSC) color reproduction. The device can produce arbitrary shape with arbitrary colors, suitable for artistic expressions, just as many as those used in information displays. Independently controlled red, green, and blue light‐emitting layers are stacked vertically. With conventional indium tin oxide technology, because of the temperature restriction, it was quite difficult to achieve low resistance on plastic substrate. The reported numbers were all more than 80 Ω/□. According to the surface mobility control using Fick's law analysis, low sheet resistance 7.34 Ω/□ on plastic film was developed. At first, flexible 7.17 cm² transparent OLED was fabricated for the performance confirmation of transparent electrode. And then polychromatic color‐tunable OLED with the same size were successfully fabricated on plastic. With optical length optimization for each color stack of polychromatic OLED, more than 100% color reproduction in National Television Committee Standard was achieved by stack design. The polychromatic device can be used for colored illumination, as well as for organic‐light‐emitting display pixels for three times emission than conventional pixel design. The device is fabricated on plastic substrate so that the polychromatic organic‐light‐emitting‐diode device is manufacturable with roll‐to‐roll production line.     

Human Muscle Mass Measurement through passive Flexible UWB-Myogram Antenna sensor to diagnose Sarcopenia

Sarcopenia disease is due to low muscle mass in humans. Sarcopenia leads to osteoporosis, metabolic syndrome and difficulty in performing day-to-day activities. At present, Dual-energy X-ray Absorptiometry (DXA) measures muscle mass with few limitations. They are variations in measurements according to region under investigation, irregularities in hydration status, and low precision in tall and obese persons. These limitations are due to low dosage level of X-ray radiations in certain muscle regions of human body such as heart, head, lower and upper extremities. This paper presents a non-invasive passive flexible Ultra Wide Band (UWB) Myogram antenna sensor for the prediction of Sarcopenia through human muscle mass measurement. This antenna is adhesively fixed on ventral surface of forearm and biceps for the measurement of skeletal and lean mass respectively. The proposed antenna sensor performs electromagnetic energy absorption from muscle tissues under radiating near-field condition. The muscle tissue signal from antenna is applied to blind source filtering-Non-negative Matrix Factorization (NMF), then subjected to Multi-Synchro Squeezing Transform (MSST), and finally correlated using linear regression machine learning algorithm to diagnose Sarcopenia. Furthermore, the proposed methodology is developed as a product through the MATLAB Mobile App compatible with Android devices. The proposed method of diagnosing Sarcopenia achieves an accuracy of 85% in fifty samples.     

非规则弯曲形变的不变量表示

摘要： 目的：全局描述不变量具有低维数和相似性测量简单的特点,本文针对于非规则弯曲形变图形,提出一种基于中轴骨架测地距离改进的全局描述不变量。方法：首先利用测地距离对于弯曲形变的不敏感性,修正图像质心位置,其次提取弯曲形变图像的中轴骨架代替图像全局域作为运算点集,并分配权重,降低计算复杂度,进而以此为基础提出一种单维度全局不变量。结果：实验结果表明该不变量具有良好的TRS不变性和弯曲形变不敏感性,相对其他传统特征表示方法,能够有效表示和鉴别非规则弯曲图形。结论：本文提出的单维度全局描述不变量,结构简单,计算方便。对于同类图像的弯曲变形,能够有效的进行区分,为该类图形的识别提供一种新的方法和思路。     

柔性OLED

柔性有机电致发光器件(FOLED)被认为是最具发展前景的下一代显示技术之一。首先简单介绍了柔性OLED的起源,分析了其基本结构原理和优势。并针对其存在的问题,重点阐述了三种衬底材料及其封装技术。     

胸部解剖结构回归模型的虚拟双能量X线减影方法

目的 探索从常规X线胸片图像中分割出骨质结构,获取仅含软组织图像的虚拟双能量X线减影的方法,旨在不增加放射剂量的条件下获取高质量的临床肺结节影像诊断效果。方法 首先将肺区自动划分出8个特定解剖结构的子区域：左右侧肺叶的上、中、下部和左右肺门;然后针对每个特定解剖区域,利用从双能量设备获取的标准胸片和其对应的骨质图像对多分辨率的大规模训练人工神经网络（MTANNs）进行训练。训练好后,可以利用该ANN处理获得该解剖结构子区域的虚拟骨质图像。融合从8个多分辨率ANNs输出的骨质图像,融合得到一幅完整的虚拟骨质图像。接下来采用总变分最小化平滑的方法抑制虚拟骨质图像中的噪声,且增强骨骼边缘。最后将虚拟骨质图像从原图中相减获得虚拟软组织图像。结果 用110幅含有肺结节的胸片图像对算法进行了测试,新方法用于常规X线胸片所得虚拟软组织图像可有效地去除原片中骨质结构影像,较清晰地保留肺结节和血管影像,有利于临床肺结节的诊断。采用新方法可使肺结节的正确识别率提高到88%（传统方法识别率为70%）。结论 基于解剖结构的人工神经网络回归模型能有效地分离出骨骼,可以广泛地应用于临床诊断,帮助放射科医生检测出肺结节。     

Lumbar posture and individual flexibility influence back muscle flexion-relaxation phenomenon while sitting

Although numerous studies have documented back muscle flexion-relaxation phenomenon (FRP) in standing postures, few studies have examined the FRP in various seated lumbar postures and individual flexibilities. This study, therefore, recruited 18 male students and assigned to low- and high-flexibility groups (9 in each). Activation of thoracic and lumbar erector spinae (ES) and lumbosacral angles were examined while participants sat in two postures (lordosis and kyphosis) and flexed their trunks at 15°, 30°, 45°, 60°, and maximum flexion. Results showed that kyphotic lumbar posture caused relatively low and unchangeable thoracic and lumbar ES activations, whereas lordotic lumbar posture engendered more contractive and varying thoracic and lumbar ES activations. Flexible participants exhibited higher thoracic ES activation than less flexible participants during lordotic sitting. Thoracic ES seemed to play a compensative role to stabilize the spine in the lordotic sitting posture, especially when the trunk was flexed over 45°. In lordotic lumbar posture, FRP occurred only in the lumbar ES; however, the activation and lumbosacral angles were still higher than those in kyphotic posture. The increased back muscle activation associated with lumbar lordosis may partially share the load on passive interspinous tissues, which are close to the discs during these flexed trunk positions.Relevance to industryThis study suggests that various lumbar postures and individual flexibilities may cause different FRP patterns when sitting. While performing seated tasks, people should exercise caution about the lumbar posture.     

Semantics analysis through elementary meanings

Abstract. Thesaurus is a collection of words classified according to some relatedness measures among them. In this paper, we lay the theoretical foundations of thesaurus construction through elementary meanings of words. The concept of elementary meanings has been advocated and utilized in compiling Webster's Collegiate Thesaurus. If each word is supplied with elementary meanings so that all its meanings are covered by them in a standard fashion, we can define various similarity measures for a given set of words. Here we take an axiomatic way to analyze semantic structure of word groups. Assuming an abstract semantic world, we deduce closed sets as generalized synonym sets. That is, we show that under certain natural axioms, we only need to consider closed sets as far as the semantics are concerned. We also show that the set of generalized synonyms described as a certain pair of closed sets has a lattice structure. In order to have a flexible thesaurus, we also analyze structure changes corresponding to three basic environmental changes: A new word-meaning relation is added, a new word or a new meaning is included with its word-meaning relations. Actually we give algorithms to have updated lattice structure from previous one for the three operations. Received: 5 May 1996 / 21 February 2000     

Pose space parameterization and style transfer of skin deformation

We present a technique to parameterize skin deformation by skeletal motion and to transfer the deformation style from one character to another. We decompose skin deformation into time‐varying signals and basis matrices by using dimension reduction techniques and then approximate the time‐varying signals by using radial basis functions with respect to joint angles that define skeletal motion. This decomposition reduces the size of deformation data to a small number of time‐varying signals that represent the complex role of muscle action. The subsequent parameterization yields a fast and intuitive control of characters; thus, it allows us to construct faithful skin deformations quickly as skeletal bones move. The representation of our parameterization allows us to capture and transfer a derived deformation style to another skeleton–skin structure without considering the input dimension of the deformation data. This style transfer can be used as a basis for realistically animating variants of sample characters that have the same skeletal topology. Parameterization of skin deformation and its style transfer can be performed within a small amount of error once the preprocessing time and control of the deformation is carried out in real time by our graphics processing unit implementation. Copyright © 2011 John Wiley & Sons, Ltd.