Repeated, intense use of muscles leads to a decline in performance known as muscle fatigue. Many muscle properties change during fatigue including the action potential, extracellular and intracellular ions, and many intracellular metabolites. A range of mechanisms have been identified that contribute to the decline of performance. The traditional explanation, accumulation of intracellular lactate and hydrogen ions causing impaired function of the contractile proteins, is probably of limited importance in mammals. Alternative explanations that will be considered are the effects of ionic changes on the action potential, failure of SR Ca2+ release by various mechanisms, and the effects of reactive oxygen species. Many different activities lead to fatigue, and an important challenge is to identify the various mechanisms that contribute under different circumstances. Most of the mechanistic studies of fatigue are on isolated animal tissues, and another major challenge is to use the knowledge generated in these studies to identify the mechanisms of fatigue in intact animals and particularly in human diseases.

/pdf/skeletal-muscle-fatigue-cellular-mechanisms-d0dzk4w31g.pdf

Skeletal Muscle Fatigue: Cellular Mechanisms

The present invention provides stretchable, and optionally printable, semiconductors and electronic circuits capable of providing good performance when stretched, compressed, flexed or otherwise deformed. Stretchable semiconductors and electronic circuits of the present invention preferred for some applications are flexible, in addition to being stretchable, and thus are capable of significant elongation, flexing, bending or other deformation along one or more axes. Further, stretchable semiconductors and electronic circuits of the present invention may be adapted to a wide range of device configurations to provide fully flexible electronic and optoelectronic devices.

http://science.sciencemag.org/content/sci/311/5758/208.full.pdf

Stretchable form of single crystal silicon for high performance electronics on rubber substrates

Gas discharge plasmas and their applications

This updated version of the popular handbook further explains all aspects of physical vapor deposition (PVD) process technology from the characterizing and preparing the substrate material, through deposition processing and film characterization, to post-deposition processing. The emphasis of the new edition remains on the aspects of the process flow that are critical to economical deposition of films that can meet the required performance specifications, with additional information to support the original material. The book covers subjects seldom treated in the literature: substrate characterization, adhesion, cleaning and the processing. The book also covers the widely discussed subjects of vacuum technology and the fundamentals of individual deposition processes. However, the author uniquely relates these topics to the practical issues that arise in PVD processing, such as contamination control and film growth effects, which are also rarely discussed in the literature. In bringing these subjects together in one book, the reader can understand the interrelationship between various aspects of the film deposition processing and the resulting film properties. The author draws upon his long experience with developing PVD processes and troubleshooting the processes in the manufacturing environment, to provide useful hints for not only avoiding problems, but also for solving problems when they arise. He uses actual experiences, called 'war stories', to emphasize certain points. Special formatting of the text allows a reader who is already knowledgeable in the subject to scan through a section and find discussions that are of particular interest. The author has tried to make the subject index as useful as possible so that the reader can rapidly go to sections of particular interest. Extensive references allow the reader to pursue subjects in greater detail if desired. The book is intended to be both an introduction for those who are new to the field and a valuable resource to those already in the field. The discussion of transferring technology between R&D and manufacturing provided in Appendix 1, will be of special interest to the manager or engineer responsible for moving a PVD product and process from R&D into production. Appendix 2 has an extensive listing of periodical publications and professional societies that relate to PVD processing. The extensive Glossary of Terms and Acronyms provided in Appendix 3 will be of particular use to students and to those not fully conversant with the terminology of PVD processing or with the English language. This title is fully revised and updated to include the latest developments in PVD process technology. It includes 'War stories' drawn from the author's extensive experience emphasize important points in development and manufacturing. Appendices include listings of periodicals and professional societies, terms and acronyms, and material on transferring technology between R&D and manufacturing.

Handbook of physical vapor deposition (PVD) processing

Atmospheric-pressure non-equilibrium plasma jets (APNP-Js), which generate plasma in open space rather than in a confined discharge gap, have recently been a topic of great interest. In this paper, the development of APNP-Js will be reviewed. Firstly, the APNP-Js are grouped based on the type of gas used to ignite them and their characteristics are discussed in detail. Secondly, one of the most interesting phenomena of APNP-Js, the ?plasma bullet?, is discussed and its behavior described. Thirdly, the very recent developments on the behavior of plasma jets when launched in a controlled environment and pressure are also introduced. This is followed by a discussion on the interaction between plasma jets. Finally, perspectives on APNP-J research are presented.

https://iopscience.iop.org/article/10.1088/0963-0252/21/3/034005/pdf

On atmospheric-pressure non-equilibrium plasma jets and plasma bullets

Recently, there has been increased interest in using atmospheric pressure plasmas for materials processing, since these plasmas do not require expensive vacuum systems. However, APGDs face instabilities. Therefore, special plasma sources have been developed to overcome this obstacle, which make use of DC, pulsed DC and AC ranging from mains frequency to RF. Recently, the APPJ was introduced, which features an α-mode of an RF discharge between two bare metallic electrodes. Basically, three different geometric configurations have been developed. A characterization of the APPJs and their applications is presented.

Recent advances in the research on non-equilibrium atmospheric pressure plasma jets

The APPJ is the subject of intensive recent research. Basically, the APPJ consists of an atmospheric-pressure RF discharge between two bare metallic electrodes and of a superimposed gas flow consisting predominantly of a rare gas. In its usual operating regime, a uniform glow discharge, which was identified as the α mode of a RF discharge, can be sustained over a wide range of gap spacings and RF powers. Maximum electron densities of0.22 × 10 12 cm -3 were assessed for helium and of 2.75 × 10 12 cm -3 for argon by evaluation of electric measurements using a simple equivalent circuit model. At low RF powers, only partial coverage of the electrodes was observed. At high RF powers, a breakdown of the α sheath occurred, and a transition to either a pure y mode or a coexisting a and y mode took place. The y mode covers only a small fraction of the electrode surface. In helium, it was easy to ignite directly a pure α discharge, but not in argon. Due to the high over-voltage needed, the ignition in argon mostly led to a coexisting α and y mode. However, through RF power reduction a transition to a pure α discharge can be initiated.

Glow Discharges Observed in Capacitive Radio-Frequency Atmospheric-Pressure Plasma Jets

Investigation of an atmospheric pressure radio-frequency capacitive plasma jet

A new type of plasma reactor for the plasma‐assisted chemical vapor deposition (PACVD) of titanium nitride (TiN) was designed and built. The reactor uses a rf discharge operating at a pressure ∼1 mbar and at a frequency of 13.56 MHz. The dependence of various properties of the coating produced on the deposition parameters is studied in detail. Besides a determination of the thickness of the coating different analytical techniques such as Auger electron spectroscopy (AES), x‐ray diffraction (XRD), and scanning electron microscopy (SEM) have been used to characterize the coating. In order to investigate mechanical properties of the deposit, Vickers hardness and critical load have been determined. TiN coatings of excellent quality have been deposited on all surfaces of objects of complex geometry. The quality of these coatings is equivalent to the quality obtained by classical CVD and physical vapor deposition (PVD) techniques. The deposition temperature of 500 °C permits the coating of hardened steel tools.

Johann Laimer

Papers

Recent advances in the research on non-equilibrium atmospheric pressure plasma jets

Recent advances in the research on non-equilibrium atmospheric pressure plasma jets

Glow Discharges Observed in Capacitive Radio-Frequency Atmospheric-Pressure Plasma Jets

Investigation of an atmospheric pressure radio-frequency capacitive plasma jet

Plasma‐assisted chemical vapor deposition of titanium nitride in a capacitively coupled radio‐frequency discharge