Forces and Torques in Muscles and Joints

JOURNAL OF FOOT AND ANKLE RESEARCH Zammit et al. Journal of Foot and Ankle Research 2010, 3:11 http://www.jfootankleres.com/content/3/1/11 Open Access RESEARCH © 2010 Zammit et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Research Reliability of the TekScan MatScan ® system for the measurement of plantar forces and pressures during barefoot level walking in healthy adults Gerard V Zammit* 1 , Hylton B Menz 1 and Shannon E Munteanu 1,2 Abstract Background: Plantar pressure systems are increasingly being used to evaluate foot function in both research settings and in clinical practice. The purpose of this study was to investigate the reliability of the TekScan MatScan ® system in assessing plantar forces and pressures during barefoot level walking. Methods: Thirty participants were assessed for the reliability of measurements taken one week apart for the variables maximum force, peak pressure and average pressure. The following seven regions of the foot were investigated; heel, midfoot, 3 rd -5 th metatarsophalangeal joint, 2 nd metatarsophalangeal joint, 1 st metatarsophalangeal joint, hallux and the lesser toes. Results: Reliability was assessed using both the mean and the median values of three repeated trials. The system displayed moderate to good reliability of mean and median calculations for the three analysed variables across all seven regions, as indicated by intra-class correlation coefficients ranging from 0.44 to 0.95 for the mean and 0.54 to 0.97 for the median, and coefficients of variation ranging from 5 to 20% for the mean and 3 to 23% for the median. Selecting the median value of three repeated trials yielded slightly more reliable results than the mean. Conclusions: These findings indicate that the TekScan MatScan ® system demonstrates generally moderate to good reliability. Background During functional activities such as walking, the human foot exerts a force upon the underlying surface, and in turn, a force of equal magnitude and opposite direction is exerted upon the foot. This force is commonly termed the ground reaction force [1,2]. Technological advances in pressure-sensing technology, enabling the quantification of the vertical component of this force and the contact area at different regions under the foot, have become commercially available for research and clinical applica- tions. This has enabled further insight into the plantar loading characteristics of the foot during functional activ- ities such as walking and running [3,4]. Elevated plantar pressures have been widely recognised as a causative factor in the development of several pedal pathologies, including the development of stress fractures [5], plantar calluses [6,7] and neuropathic ulceration [8]. Factors shown to be associated with elevated plantar pressures include forefoot deformity [9], increased heel pad stiffness [10] and lesser toe deformity [11]. The anal- ysis of plantar forces and pressures has also played an integral role in the management of lower limb disorders. Specifically, footwear modifications [12] and redistribu- tive insoles [13] aimed at offloading areas of high pres- sure prone to ulceration have been assessed for effectiveness in patients with diabetic peripheral neurop- athy. Commercially available systems currently employed by clinicians and researchers to assess dynamic plantar pres- sures include in-shoe measurement systems (Novel Pedar ® , TekScan F-Scan ® , RS-Scan Insole ® and IVB Bio- foot ® ) and platform systems (Novel Emed ® and the RS- Scan Footscan ® ) [14]. The validity of these measurement systems has been documented throughout the literature, suggesting they are able to accurately quantify dynamic * Correspondence: Forces and Torques in Muscles and Joints Forces and Torques in Muscles and Joints Bởi: OpenStaxCollege Muscles, bones, and joints are some of the most interesting applications of statics There are some surprises Muscles, for example, exert far greater forces than we might think [link] shows a forearm holding a book and a schematic diagram of an analogous lever system The schematic is a good approximation for the forearm, which looks more complicated than it is, and we can get some insight into the way typical muscle systems function by analyzing it Muscles can only contract, so they occur in pairs In the arm, the biceps muscle is a flexor—that is, it closes the limb The triceps muscle is an extensor that opens the limb This configuration is typical of skeletal muscles, bones, and joints in humans and other vertebrates Most skeletal muscles exert much larger forces within the body than the limbs apply to the outside world The reason is clear once we realize that most muscles are attached to bones via tendons close to joints, causing these systems to have mechanical advantages much less than one Viewing them as simple machines, the input force is much greater than the output force, as seen in [link] 1/16 F Forces and Torques in Muscles and Joints (a) The figure shows the forearm of a person holding a book The biceps exert a force B to support the weight of the forearm and the book The triceps are assumed to be relaxed (b) Here, you can view an approximately equivalent mechanical system with the pivot at the elbow joint as seen in [link] Muscles Exert Bigger Forces Than You Might Think Calculate the force the biceps muscle must exert to hold the forearm and its load as shown in [link], and compare this force with the weight of the forearm plus its load You may take the data in the figure to be accurate to three significant figures Strategy There are four forces acting on the forearm and its load (the system of interest) The magnitude of the force of the biceps is FB; that of the elbow joint is FE; that of the weights of the forearm is wa, and its load is wb Two of these are unknown (FB and FE ), so that the first condition for equilibrium cannot by itself yield FB But if we use the second condition and choose the pivot to be at the elbow, then the torque due to FE is zero, and the only unknown becomes FB 2/16 Forces and Torques in Muscles and Joints Solution The torques created by the weights are clockwise relative to the pivot, while the torque created by the biceps is counterclockwise; thus, the second condition for equilibrium (net τ = 0) becomes r2wa + r3wb = r1FB Note that sin θ = for all forces, since θ = 90º for all forces This equation can easily be solved for FB in terms of known quantities, yielding FB = r2wa + r3wb r1 Entering the known values gives FB = ( ) ( ) (0.160 m)(2.50 kg) 9.80 m/s2 + (0.380 m)(4.00 kg) 9.80 m/s2 0.0400 m which yields FB = 470 N Now, the combined weight of the arm and its load is (6.50 kg)(9.80 m/s2) = 63.7 N, so that the ratio of the force exerted by the biceps to the total weight is FB wa + wb = 470 63.7 = 7.38 Discussion This means that the biceps muscle is exerting a force 7.38 times the weight supported In the above example of the biceps muscle, the angle between the forearm and upper arm is 90° If this angle changes, the force exerted by the biceps muscle also changes In addition, the length of the biceps muscle changes The force the biceps muscle can exert depends upon its length; it is smaller when it is shorter than when it is stretched Very large forces are also created in the joints In the previous example, the downward force FE exerted by the humerus at the elbow joint equals 407 N, or 6.38 times the total weight supported (The calculation of FE is straightforward and is left as an endof-chapter problem.) Because muscles can contract, but not expand beyond their resting length, joints and muscles often exert forces that act in opposite directions and thus subtract (In the above example, the upward force of the muscle minus the downward 3/16 Forces and Torques in Muscles and Joints force of the joint equals the weight supported—that is, 470 N – 407 N = 63 N, approximately equal to the weight supported.) Forces in muscles and joints are largest when their load is a long distance from the joint, as the book is in the previous example In racquet sports such as tennis the constant extension of the arm during game play creates large forces in this way The mass times the lever arm of a tennis racquet is an important factor, and many players use the heaviest racquet they can handle It is no wonder that joint deterioration and damage to the tendons in the elbow, such as “tennis elbow,” can result from repetitive motion, undue torques, and possibly poor racquet selection in such sports Various tried techniques for holding and using a racquet or bat or stick not only increases sporting prowess but can minimize fatigue and long-term damage to the body For example, tennis ...BioMed Central Page 1 of 8 (page number not for citation purposes) Journal of Inflammation Open Access Research Demonstration of a novel technique to quantitatively assess inflammatory mediators and cells in rat knee joints Nicola J Barton* 1 , David A Stevens 2 , Jane P Hughes 2 , Adriano G Rossi 3 , Iain P Chessell 2 , Alison J Reeve 2 and Daniel S McQueen 1 Address: 1 Division of Neuroscience, University of Edinburgh, Medical College, 1 George Sq, Edinburgh, EH8 9JZ, UK, 2 Neurology CEDD, GlaxoSmithKline R&D Ltd, Harlow, Essex CM19 5AW, UK and 3 MRC Centre for Inflammation Research, The Queens Medical Research Institute, University of Edinburgh, EH16 4TJ, UK Email: Nicola J Barton* - N.J.Barton@sms.ed.ac.uk; David A Stevens - David.A.Stevens@gsk.com; Jane P Hughes - Jane.P.Hughes@gsk.com; Adriano G Rossi - Adriano.Rossi@ed.ac.uk; Iain P Chessell - Iain.P.Chessell@gsk.com; Alison J Reeve - Alison.J.Reeve@gsk.com; Daniel S McQueen - D.S.McQueen@ed.ac.uk * Corresponding author Abstract Background: The inflammation that accompanies the pain and swelling associated with osteo- and rheumatoid arthritis is mediated by complex interactions of inflammatory mediators. Cytokines play a pivotal role in orchestrating many of these processes, including inflammatory cell recruitment, adhesion and activation. In addition, prostaglandins are secreted into the synovial cavity and are involved in perpetuation of local inflammation, vasodilatation and vasoconstriction, and also with bone resorption. Pre-clinical models have been developed in order to correlate to the human disease and principle among these is the adjuvant-induced arthritis model in the rat. Methods: We have developed a technique to quantitatively assess the contents of synovial fluid samples from rat joints. Two needles joined together are inserted into the knee joint of anaesthetised rats and connected to a Watson-Marlow perfusion pump. Sterile saline is infused and withdrawn at 100 µl min -1 until a 250 µl sample is collected. Results: Our results demonstrate up to 125 fold increases in synovial IL1α and IL1β concentrations, approximately 30 fold increases in levels of IL6 and IL10 and a 200–300 fold elevation in synovial concentrations of TNFα during FCA-induced experimental arthritis. Finally, this novel technique has demonstrated a dose-response relationship between FCA and the total cell counts of synovial perfusates. Conclusion: In summary, this new technique provides a robust method for quantifying inflammatory mediators and cells from the synovial cavity itself, thereby detailing the inflammatory processes from within the capsule and excluding those processes occurring in other tissues surrounding the entire articulation. Published: 13 June 2007 Journal of Inflammation 2007, 4:13 doi:10.1186/1476-9255-4-13 Received: 19 December 2006 Accepted: 13 June 2007 This article is available from: http://www.journal-inflammation.com/content/4/1/13 © 2007 Barton et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0 ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Journal of Inflammation 2007, 4:13 http://www.journal-inflammation.com/content/4/1/13 Page 2 of 8 (page number not for citation purposes) 1. Background Inflammatory joint diseases such as rheumatoid arthritis (RA) are regulated by complex interactions involving many mediators, such as prostanoids and cytokines. The infiltration of cells into the synovial tissue and joint space is another key characteristic of synovitis, which combined with release of these mediators and degradative enzymes, eventually leads to cartilage and bone destruction (for reviews see [1]). Measuring the levels of these mediators of inflammation in the synovial fluid from patients can provide informa- tion about the underlying A MECHANISM-BASED APPROACH — VOID GROWTH AND COALESCENCE IN POLYMERIC ADHESIVE JOINTS CHEW HUCK BENG (M.Eng, B.Eng (Hons), NUS) A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF MECHANICAL ENGINEERING NATIONAL UNIVERSITY OF SINGAPORE 2007 ii To my parents, and my wife, who truly are the wind beneath my wings. iii LIST OF PUBLICATIONS Journal Papers [1] Chew, H. B., Guo, T. F. and Cheng, L., Vapor pressure and residual stress effects on the toughness of polymeric adhesive joints. Engineering Fracture Mechanics, 71 (2004), 2435-2448. [2] Chew, H. B., Guo, T. F. and Cheng, L., Vapor pressure and residual stress effects on the failure of an adhesive film. International Journal of Solids and Structures, 42 (2005), 4795-4810. [3] Chew, H. B., Guo, T. F. and Cheng, L., Vapor pressure and residual stress effects on mixed mode toughness of an adhesive film. International Journal of Fracture, 134 (2005), 349-368. [4] Chew, H. B., Guo, T. F. and Cheng, L., Vapor pressure and voiding effects on thin film damage. Thin Solid Films, 504 (2006), 325-330. [5] Chew, H. B., Guo, T. F. and Cheng, L., Effects of pressure-sensitivity and plastic dilatancy on void growth and interaction. International Journal of Solids and Structures, 43 (2006), 6380-6397. [6] Chew, H. B., Guo, T. F. and Cheng, L., Pressure-sensitive ductile layers − I. Modeling the growth of extensive damage. International Journal of Solids and Structures, 44 (2007), 2553-2570. [7] Chew, H. B., Guo, T. F. and Cheng, L., Pressure-sensitive ductile layers − II. 3D models of extensive damage. International Journal of Solids and Structures, 44 (2007), 5349-5368. [8] Chew, H. B., Guo, T. F. and Cheng, L., Influence of non-uniform initial porosity distribution on adhesive failure in electronic packages. IEEE Transactions on Components and Packaging Technologies, (2007), in Press. Conference Papers [1] Chew, H. B., Guo, T. F. and Cheng, L., Modeling interface delamination in plastic IC packages. Proceedings of APACK 2001 Conference on Advances in Packaging (ISBN 981-04-4638-1), 5-7 Dec 2001, Singapore, pp. 381- 388. [2] Chew, H. B., Guo, T. F. and Cheng, L., A mechanism-based approach for interface toughness of ductile layer joining elastic solids. JSME/ASME Proceedings of International Conference on Materials and Processing, 15-18 Oct 2002, Hawaii, Vol. 1, pp. 570-575. [3] Chew, H. B., Guo, T. F. and Cheng, L., Computational study of vapor pressure and residual stress effects on adhesive failure. Proceedings of International Conference on Scientific & Engineering Computation, 30 June - 02 July 2004, Singapore. iv [4] Chew, H. B., Guo, T. F. and Cheng, L., Computational study of compressive failure of metallic foam. Proceedings of International Conference on Computational Methods (ISBN-10 1-4020-3952-2), 15-17 Dec 2004, Singapore, Vol. 1, pp. 563-568. [5] Chew, H. B., Guo, T. F. and Cheng, L., Vapor pressure and voiding effects on thin film damage. Presented in International Conference on Materials for Advanced Technologies, 3-8 July 2005, Singapore. [6] Chew, H. B., Guo, T. F. and Cheng, L., Influence of non-uniform initial porosity distribution on adhesive failure in electronic packages. Proceedings of 7th Electronics Packaging Technology Conference (ISBN 0-7803-9578-6), 7-9 Dec 2005, Singapore, Vol. 2, pp. 6-11. [7] Chew H. B., Guo, T. F. and Cheng, L., Void growth and damage ahead of a crack in pressure-sensitive dilatant polymers. Proceedings of International Conference on High Performance Structures and Materials (ISSN 1743-3509), 3-5 May 2006, Ostend, Belgium, Vol. 85, pp. 501-510. [8] Chew, H. B., Guo, T. F. and Cheng, L., Modeling adhesive failure in electronic packages. Proceedings of 8th Electronics Packaging Technology Conference (ISBN 1-4244-0664-1), 6-8 Dec 2006, Singapore, Vol. 2, pp. 787-792. v ACKNOWLEDGEMENTS I wish to acknowledge and thank those people who contributed to this thesis: A/Prof. Cheng Li, thesis advisor, for her unwavering SOLVATION FORCES AND CONTACT MECHANICS AT THE NANOMETER SCALE IN MOLECULAR LIQUIDS NITYA NAND GOSVAMI NATIONAL UNIVERSITY OF SINGAPORE 2008 SOLVATION FORCES AND CONTACT MECHANICS AT THE NANOMETER SCALE IN MOLECULAR LIQUIDS NITYA NAND GOSVAMI B. Tech., Metallurgical Engineering Institute of Technology, Banaras Hindu University (IT-BHU), India A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF MECHANICAL ENGINEERING NATIONAL UNIVERSITY OF SINGAPORE 2008 Acknowledgements I would like to express my sincere gratitude to a number of unforgettable people whom I worked with as well as got to know closely during my research work at the Institute of Materials Research and Engineering (IMRE) and the National University of Singapore (NUS). I’m thankful to my supervisors, Dr. Sujeet Kumar Sinha for giving me a great opportunity to pursue my research at NUS and providing incessant moral support and motivation, Prof. M. P. Srinivasan for helping me throughout my research with his immense knowledge of chemistry, and most importantly, Dr. Sean O’Shea, who not only brought me closer to the reality of science, but also enthralled me with his kindness, quick wit, remarkable patience and extraordinarily inspiring supervision. I’ll particularly miss the exciting group discussions at our favorite hangout place, Pasir Panjang Village. I would like to thank Dr.Wulf Hofbauer for several exhilarating discussions, which gave me a flavor of his in-depth knowledge and experience and Prof. Chandrasekhar Natarajan for unwearyingly answering my never-ending list of questions. I would also like to thank my close friends at IMRE including Lena Lui, Ong Yi Ching, Leonard Lim, Linda Kunardi, Dr. Cedric Troadec, Kedar Hippalgaonkar, Dr. Abir De Sarkar and Dr. Rajeev Ahluwalia for their generosity and constant support, as well as Dr. Satyanarayana Nalam from NUS and Dr. Sudhiranjan Tripathy from IMRE for providing me a great opportunity to work together on several interesting ideas. Last but not least, I’m truly grateful to my parents for their constant care and motivation, which is the biggest strength for my accomplishments. i Table of Contents 1. Introduction…………………………………………………………………… . 1.1. Motivation………………………………………………………………… 1.2. Thesis Outline…………………………………………………………………. 1 2. Literature Review…………………………………………………………… 2.1. Solvation Force……………………………………………………………… . 2.2. Experimental Techniques to measure Surface Forces………………………… 2.2.1. Surface Force Apparatus (SFA)……………………………………… 2.2.2. Solvation Forces using Surface Force Apparatus……………………… 2.2.3. Scanning Probe Microscopy (SPM)…………………………………… 2.2.4. Solvation Forces Using Atomic Force Microscopy…………………… 2.3. Computer Simulations of Solvation Forces…………………………………… 2.4. Contact Mechanics of Solids………………………………………………… 2.4.1. Hertz Model………………………………………………………… . 2.4.2. DMT Model………………………………………………………… . 2.4.3. JKR Model…………………………………………………………… . 2.4.4. Maugis-Dugdale Model……………………………………………… . 2.5. Charge Transport at the Nanoscale…………………………………………… 2.5.1. Point Contact Conductance………………………………………… . 2.5.2. Tunneling through a Metal-Molecule-Metal Junction…………………. 2.6. Problems Requiring Nanoscale Current and Force Measurements…………… 2.6.1. Lubrication and Friction……………………………………………… 2.6.2. Molecular Electronics……………………………………………… 8 11 11 12 15 19 22 24 25 27 27 29 31 31 33 36 36 39 3. Experimental Methodologies……………………………………………………………… . 3.1. Scanning Probe Microscopy………………………………………………… . 3.1.1. AFM Setup…………………………………………………………… 3.1.2. Force Measurements in Static Mode………………………………… . 3.1.3. Sample Modulation AFM in liquids…………………………………… 3.2. AFM Piezo Calibration……………………………………………………… 3.2.1. Z piezo calibration…………………………………………………… . 3.2.2. X and Y piezo calibration……………………………………………… 3.3. Tip Preparation and Characterization…………………………………………. 3.4. Materials…………………………………………………………………… . 3.4.1. HOPG………………………………………………………………… 3.4.2. Au (111) on Mica……………………………………………………… 3.4.3. MINISTRY OF FINANCE ACADEMY OF FINANCE FACULTY OF FOREIGN LANGUAGE  GRADUATION THESIS ACCOUNTING IN COLLECTING PRODUCTION COST AND CALCULATING COST OF FINISHED GOODS IN HAPRO VODKA JOINTSTOCK COMPANY DINH THI TRANG CQ48/51-04 HANOI, 5/2014 MINISTRY OF FINANCE ACADEMY OF FINANCE FACULTY OF FOREIGN LANGUAGE  GRADUATION THESIS ACCOUNTING IN COLLECTING PRODUCTION COST AND CALCULATING COST OF FINISHED GOODS IN HAPRO VODKA JOINTSTOCK COMPANY MAJOR : English for Finance andAccounting Code : 51 STUDENT : Dinh Thi Trang GROUP : CQ48/51-04 SUPERVISOR : Cao Xuan Thieu, M.A HANOI, 5/2014 GRADUATION THESIS DECLARATION This thesis is the presentation of result of my own research during the time of internship in Institute of International Finance Education (IIFE), and has not been submitted for a degree to any other universities or institutions To the best of my knowledge, the thesis does not contain material previously published or another people, except where due acknowledgement is made in the text Hanoi, April 11, 2014 Dinh Thi Thuy Trinh DINH THI THUY TRINH - CQ48/51-04 Page GRADUATION THESIS ABSTRACT This thesis focuses on the translation quality assessment of the Vietnamese version of financial and accounting terminologies in Paper F3Financial accounting (International) belonging ACCA program translated by translators in IIFE Specifically, it is more concerned with the assessment of terminologies at word level and above word level in two groups: sub technical and highly technical group The study starts with the introduction by giving a rationale for the study, pointing out aims, scope and methods of the study Chapter I presents the study’s literature review It elaborates on the issues relevant to the study including the notion and classification of translation, translation equivalence, technical translation, technical terminology, translation quality assessment, document review Chapter II analyses the source language text and concentrates on financial and accounting terminologies through document review to arrange them in sub technical and highly technical group resting with characteristics of each group Simultaneously, this chapter also compares the original text with the translation to evaluate the accuracy of terminologies Chapter III summaries the results of study and gives recommendations for improving the quality of translation DINH THI THUY TRINH - CQ48/51-04 Page GRADUATION THESIS ACKNOWLEDGEMENT Firstly, I would like to express my profound gratitude to my supervisor Pham Thi Lan Phuong, M.A, who has continuously encouraged me to develop my savvy of the subject Without her motivation, enthusiasm and intensive expertise, this thesis could not be completed I also wish to express my sincere thanks to Tran Minh Thu, M.A for her directions, correction and comments during the course of my writing Moreover, I truly appreciate the internship opportunities that Assoc Dr Bui Duong Nghieu has offered me at Institute of International Finance Education (IIFE) And thanks to him, I have a chance to access documents translated, which are surely contributed to the foundation of my thesis I also owe my debt of gratitude to staffs in IIFE, especially the international training development office for their kindness and support Finally, I would like to show my deep gratitude to my parents for their care, support, encouragement, without which my thesis would not have been accomplished DINH THI THUY TRINH - CQ48/51-04 Page GRADUATION THESIS LIST OF TABLES AND FIGURES Figure 2.1The percentage of single verb and noun in sub technical group….28 Figure 2.2 The main components in sub technical group above word level 33 Figure 2.3 The comparison in number between single noun in sub technical group and highly technical group……………… ………………………… 36 Table 2.1 The most appearing times of single verbs in the textbook……… 29 DINH THI THUY TRINH - CQ48/51-04 Page GRADUATION THESIS LIST OF ABBREVIATIONS SL: Source language TL: Target language ST: Source ... some interesting complexities in real systems of muscles, bones, and joints For instance, the pivot point in many joints changes location as the joint is flexed, so that 8/16 Forces and Torques in. .. abnormally large forces are created in the back muscles and spine 5/16 Forces and Torques in Muscles and Joints People adjust their stance to maintain balance (a) A father carrying his son piggyback... torques in the treatment of muscles and joints In physical therapy, an exercise routine can apply a particular force and torque which can, over a period of time, revive muscles and joints Some