scholarly journals MEMs from the Nanoscale Up

2007 ◽  
Vol 129 (03) ◽  
pp. 24-29 ◽  
Author(s):  
Arthur C. Ratzel
Keyword(s):  
Leading Edge ◽  
Consumer Products ◽  
Mems Devices ◽  
Science And Engineering ◽  
Gas Damping ◽  
High Shock ◽  
Mems Technology ◽  
Silicon Based ◽  
Development Laboratory

This article discusses growing role of silicon micro-electron-mechanical systems (MEMS) technology in automotive and consumer products, telecommunications, radio-frequency applications, and medical care. The article also highlights that silicon-based MEMS devices must be constructed in clean rooms, such as one at Sandia's Microelectronics Development laboratory. According to engineers, the search for an in-depth understanding of wear mechanisms in dynamic silicon MEMS is expected to drive an ambitious wave of leading-edge research into microscale science and engineering, distinct from that which prevailed at the mesoscale. It has been found that gas damping between MEMS structures and the substrate, within the sealed package, can cause serious nonlinearities. While this doesn't lead to failure in the classic sense, it may make it harder to close a switch. On the plus side, gas damping can provide a cushion that enables a MEMS device to survive surprisingly high shock loads.

scholarly journals CVD grown Graphene Microfilms as a Promising Microscaled Solid Lubricant for the Lubrication of Silicon MEMS Devices

2021 ◽  
Author(s):  
Muhammad Chhattal ◽  
Abdul Ghaffar ◽  
Fayaz Ali Dharejo ◽  
Salamat Ali
Keyword(s):  
Industrial Development ◽  
Friction Pair ◽  
Chemical Vapor ◽  
Tribological Performance ◽  
Mems Devices ◽  
Mems Technology ◽  
Transfer Method ◽  
Grown Graphene ◽  
Pin On Disk ◽  
Silicon Based

Abstract Friction, wear, stiction, adhesion, and absence of suitable lubrication methods are important challenges, severely restricting and limiting the expeditious development of Microelectromechanical system (MEMS) technology. This paper aims to explore the potential of chemical vapor deposition (CVD) grown graphene microfilms for the lubrication of sliding silicon MEMS devices to reduce friction and wear problems. A novel silicon-based pin-on-disk friction-pair is designed to mimic sliding MEMS working conditions. Pure graphene-based microfilms are fabricated on the Cu substrate via a CVD method and transferred to the silicon substrate via the PMMA transfer method. To investigate microfilms' surface quality and morphology, microfilms are characterized via Raman spectroscopy, AFM, and SEM. For the tribological performance evaluation, different tribological tests were conducted using the microtribometer. Results show that microfilms remarkably reduced the friction coefficient and wear in the MEMS devices; however, microfilms' tribological performance depends on the roughness and the number of films on the specimen. This remarkable tribological performance suggests that graphene microfilms have the potential to increase the reliability and wear lifespan of MEMS devices. It is foreseeable that this lubrication method can be a step towards the expeditious industrial development of silicon MEMS devices.

scholarly journals Life Cycle Assessment and Judgement

NanoEthics ◽  
2020 ◽  
Vol 14 (3) ◽  
pp. 271-283
Author(s):  
Christopher Nathan ◽  
Stuart Coles
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Academic Community ◽  
Consumer Products ◽  
Free Inquiry ◽  
Technology Project ◽  
Lively Debate ◽  
Technology Product

AbstractIt has become a standard for researchers carrying out biotechnology projects to do a life cycle assessment (LCA). This is a process for assessing the environmental impact of a technology, product or policy. Doing so is no simple matter, and in the last decades, a rich set of methodologies has developed around LCA. However, the proper methods and meanings of the process remain contested. Preceding the development of the international standard that now governs LCA, there was a lively debate in the academic community about the inclusion of ‘values’ within the process. We revisit this debate and reconsider the way forward for LCA. We set out ways in which those outside of science can provide input into LCAs by informing the value assumptions at stake. At the same time, we will emphasize that the role of those within the scientific community need not (and sometimes, will inevitably not) involve value-free inquiry. We carry out this exploration through a case study of a particular technology project that sought ways to produce industrial and consumer products from algal oils.

The Role of Healthcare Professionals in Environmental Health and Fertility Decision-Making

2017 ◽  
Vol 27 (1) ◽  
pp. 28-50 ◽  
Author(s):  
Ellen Sweeney
Keyword(s):  
Decision Making ◽  
Healthcare Professionals ◽  
Endocrine Disrupting Chemicals ◽  
Consumer Products ◽  
Professional Organizations ◽  
Toxic Substances ◽  
Industrial Chemicals ◽  
Fertility Decision ◽  
Guidelines And Recommendations

There is increasing evidence that raises specific concerns about prenatal exposures to toxic substances which makes it necessary to consider everyday exposures to industrial chemicals and toxic substances in consumer products, including endocrine disrupting chemicals. Pregnant women have measurable levels of numerous toxic substances from exposures in their everyday environments, including those which are associated with adverse developmental and reproductive health outcomes. As a result, environmental contexts have begun to influence the decisions women make related to fertility, as well as the formal guidelines and advice provided by healthcare professionals. This article provides an overview of the potential role for obstetricians and gynecologists in educating their patients about the role of toxic substances in fertility decision-making and pregnancy. It explores the emerging guidelines and recommendations from professional organizations and problematizes the limitations of these approaches.

scholarly journals Akt isoforms differentially regulate neutrophil functions

Blood ◽  
2010 ◽  
Vol 115 (21) ◽  
pp. 4237-4246 ◽  
Author(s):  
Jia Chen ◽  
Haiyang Tang ◽  
Nissim Hay ◽  
Jingsong Xu ◽  
Richard D. Ye
Keyword(s):  
Kinase Inhibitor ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Leading Edge ◽  
Neutrophil Activation ◽  
Enzyme Release ◽  
Wild Type ◽  
Akt Isoforms ◽  
Phosphoinositide 3 Kinase ◽  
O2 Production

In neutrophils, the phosphoinositide 3-kinase/Akt signaling cascade is involved in migration, degranulation, and O2− production. However, it is unclear whether the Akt kinase isoforms have distinct functions in neutrophil activation. Here we report functional differences between the 2 major Akt isoforms in neutrophil activation on the basis of studies in which we used individual Akt1 and Akt2 knockout mice. Akt2−/− neutrophils exhibited decreased cell migration, granule enzyme release, and O2− production compared with wild-type and Akt1−/− neutrophils. Surprisingly, Akt2 deficiency and pharmacologic inhibition of Akt also abrogated phorbol ester-induced O2− production, which was unaffected by treatment with the phosphoinositide 3-kinase inhibitor LY294002. The decreased O2− production in Akt2−/− neutrophils was accompanied by reduced p47phox phosphorylation and its membrane translocation, suggesting that Akt2 is important for the assembly of phagocyte nicotinamide adenine dinucleotide phosphate oxidase. In wild-type neutrophils, Akt2 but not Akt1 translocated to plasma membrane upon chemoattractant stimulation and to the leading edge in polarized neutrophils. In the absence of Akt2, chemoattractant-induced Akt protein phosphorylation was significantly reduced. These results demonstrate a predominant role of Akt2 in regulating neutrophil functions and provide evidence for differential activation of the 2 Akt isoforms in neutrophils.

scholarly journals Exploring the role of anticipated emotions in product adoption and usage

2018 ◽  
Vol 35 (3) ◽  
pp. 300-316 ◽  
Author(s):  
Debora Bettiga ◽  
Lucio Lamberti
Keyword(s):  
Decision Making ◽  
Conceptual Model ◽  
Structural Equation ◽  
Consumer Products ◽  
Product Adoption ◽  
Radical Product ◽  
Content Type ◽  
Product Decision ◽  
Anticipated Emotions

Purpose This study aims to explore the role of positive and negative anticipated emotions on adoption and continued usage of consumer products. The components of value eliciting anticipated emotions are investigated as well. Design/methodology/approach The conceptual model proposed is tested in two empirical studies, one focussing on functional and hedonic products and one on incremental and radical product innovations. Data are collected through online surveys on consumers and are analysed using structural equation modelling. Findings Results confirm the ability of anticipated emotions to influence product decision-making process. Moreover, anticipated emotions mediate the influence of value perceptions on product attitude. Findings show that these relationships vary greatly between initial adoption and further usage of the product. Practical implications Findings from this study may help marketers in the development of the right brand strategies and communication campaigns, aimed at building emotional connections with the consumer which prompt product adoption and usage. Originality/value Anticipated emotions, the predictions about the emotional consequences of a behaviour, have been acknowledged as strong drivers of consumer choices. Despite that, the role of anticipated emotions in product decision-making has not been explored yet. The present research, by means of a novel conceptual model, uncovers the role of anticipated emotions in both product adoption and continued usage decisions and depicts the components of value arousing such anticipated emotions.

ZMP: A REVIEW OF SOME BASIC MISUNDERSTANDINGS

2006 ◽  
Vol 03 (02) ◽  
pp. 153-175 ◽  
Author(s):  
MIOMIR VUKOBRATOVIĆ ◽  
BRANISLAV BOROVAC ◽  
VELJKO POTKONJAK
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Balance ◽  
Decisive Role ◽  
Humanoid Robots ◽  
Ground Contact ◽  
Science And Engineering ◽  
Theoretical Assumptions ◽  
Zero Moment ◽  
Basic Characteristics

One of basic characteristics of the regular bipedal walk of humanoid robots is the maintenance of their dynamic balance during the walk, whereby a decisive role is played by the unpowered degrees of freedom arising at the foot–ground contact. Hence, the role of the Zero-Moment Point (ZMP) as an indicator of dynamic balance is indispensable. This paper gives a detailed discussion of some basic theoretical assumptions related to the ZMP in the light of imprecise, and even incorrect, interpretations that have recently appeared, and which have led to some erroneous conclusions. Examples are given to show some erroneous basic attitudes and the genesis of some of them is indicated. It is also pointed out that in the domain of bipedal walk there are still notions that are not clearly defined and their meanings differentiated in some related branches of science and engineering. One of the examples is dynamic balance and stability, which are often used interchangeably.

Chlamydia pneumoniae infection induces vascular smooth muscle cell migration via Rac1 activation

2014 ◽  
Vol 63 (2) ◽  
pp. 155-161 ◽  
Author(s):  
Junxia Zhang ◽  
Haiwei Wang ◽  
Lijun Zhang ◽  
Tengteng Zhang ◽  
Beibei Wang ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Cell Migration ◽  
Botulinum Toxin ◽  
Vascular Smooth Muscle ◽  
Chlamydia Pneumoniae ◽  
Leading Edge ◽  
Primary Role ◽  
Phosphatidylinositol 3 Kinase ◽  
Smooth Muscle Cell Migration

Chlamydia pneumoniae infection has been shown to be associated with the development of atherosclerosis by promoting the migration of vascular smooth muscle cells (VSMCs). However, how C. pneumoniae infection induces VSMC migration is not fully understood. A primary role of Ras-related C3 botulinum toxin substrate 1 (Rac1) is to generate a protrusive force at the leading edge that contributes to cell migration. Whether Rac1 activation plays a role in C. pneumoniae infection-induced VSMC migration is not well defined. In the present study, we therefore examined Rac1 activation in C. pneumoniae-infected rat primary VSMCs and the role of Rac1 activation in C. pneumoniae infection-induced VSMC migration. Glutathione S-transferase pull-down assay results showed that Rac1 was activated in C. pneumoniae-infected rat primary VSMCs. A Rac1 inhibitor, NSC23766 (50 µM,) suppressed Rac1 activation stimulated by C. pneumoniae infection, and thereby inhibited C. pneumoniae infection-induced VSMC migration. In addition, C. pneumoniae infection-induced Rac1 activation in the VSMCs was blocked by LY294002 (25 µM), an inhibitor of phosphatidylinositol 3-kinase (PI3K). Taken together, these data suggest that C. pneumoniae infection promotes VSMC migration, possibly through activating Rac1 via PI3K.

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