Characterization of Signal Propagation through Limb Joints for Intrabody Communication

2011 ◽  
Vol 1 (2) ◽  
pp. 1-12
Author(s):  
MirHojjat Seyedi ◽  
Zibo Cai ◽  
Daniel T. H. Lai
Keyword(s):  
Signal Propagation

Activins, Inhibins, and Follistatins: From Endocrinology to Signaling. A Paradigm for the New Millennium

2002 ◽  
Vol 227 (9) ◽  
pp. 724-752 ◽  
Author(s):  
Corrine Welt ◽  
Yisrael Sidis ◽  
Henry Keutmann ◽  
Alan Schneyer
Keyword(s):  
Hormone Secretion ◽  
Signal Propagation ◽  
Cellular Level ◽  
Model Systems ◽  
Pituitary Hormone ◽  
New Paradigm ◽  
Activin Signaling ◽  
Physiological Relevance ◽  
Paracrine Growth Factor

It has been 70 years since the name inhibin was used to describe a gonadal factor that negatively regulated pituitary hormone secretion. The majority of this period was required to achieve purification and definitive characterization of inhibin, an event closely followed by identification and characterization of activin and follistatin (FS). In contrast, the last 15–20 years saw a virtual explosion of information regarding the biochemistry, physiology, and biosynthesis of these proteins, as well as identification of activin receptors, and a unique mechanism for FS action—the nearly irreversible binding and neutralization of activin. Many of these discoveries have been previously summarized; therefore, this review will cover the period from the mid 1990s to present, with particular emphasis on emerging themes and recent advances. As the field has matured, recent efforts have focused more on human studies, so the endocrinology of inhibin, activin, and FS in the human is summarized first. Another area receiving significant recent attention is local actions of activin and its regulation by both FS and inhibin. Because activin and FS are produced in many tissues, we chose to focus on a few particular examples with the most extensive experimental support, the pituitary and the developing follicle, although nonreproductive actions of activin and FS are also discussed. At the cellular level, it now seems that activin acts largely as an autocrine and/or paracrine growth factor, similar to other members of the transforming growh factor β superfamily. As we discuss in the next section, its actions are regulated extracellularly by both inhibin and FS. In the final section, intracellular mediators and modulators of activin signaling are reviewed in detail. Many of these are shared with other transforming growh factor β superfamily members as well as unrelated molecules, and in a number of cases, their physiological relevance to activin signal propagation remains to be elucidated. Nevertheless, taken together, recent findings suggest that it may be more appropriate to consider a new paradigm for inhibin, activin, and FS in which activin signaling is regulated extracellularly by both inhibin and FS whereas a number of intracellular proteins act to modulate cellular responses to these activin signals. It is therefore the balance between activin and all of its modulators, rather than the actions of any one component, that determines the final biological outcome. As technology and model systems become more sophisticated in the next few years, it should become possible to test this concept directly to more clearly define the role of activin, inhibin, and FS in reproductive physiology.

Design and Demonstration of 40 micron Bump Pitch Multi-layer RDL on Panel-based Glass Interposers

2015 ◽  
Vol 2015 (1) ◽  
pp. 000379-000385 ◽  
Author(s):  
Brett Sawyer ◽  
Yuya Suzuki ◽  
Zihan Wu ◽  
Hao Lu ◽  
Venky Sundaram ◽  
...  
Keyword(s):  
High Speed ◽  
Metal Layer ◽  
Low Cost ◽  
Signal Propagation ◽  
Additive Process ◽  
Thin Glass ◽  
Fine Pitch ◽  
Data Rates ◽  
Insertion Losses

This paper describes the design, fabrication, and characterization of a two-metal layer RDL structure at 40 um pitch on thin glass interposers. Such an RDL structure is targeted at 2.5D glass interposer packages to achieve up to 1 TB/s die-to-die bandwidth and off-interposer data rates greater than 400 Gb/s, driven by consumer demand of online services for mobile devices. Advanced packaging architectures including 2.5D and 3D interposers require fine line lithography beyond the capabilities of current organic package substrates. Although silicon interposers fabricated using back-end-of-line processes can achieve these RDL wiring densities, they suffer from high electrical loss and high cost. Organic interposers with high wiring densities have also been demonstrated recently using a single sided thin film process. This paper goes beyond silicon and organic interposers in demonstrating fine pitch RDL on glass interposers fabricated by low cost, double sided, and panel-scalable processes. The high modulus and smooth surface of glass helps to achieve lithographic pitch close to that of silicon. Furthermore, the low loss tangent of glass helps in reducing dielectric losses, thus improving high-speed signal propagation. A semi-additive process flow and projection excimer laser ablation was used to fabricate two-metal layer RDL structures and bare glass RDL layers. A minimum of 3 um lithography and 20 um mico-via pitch was achieved. High-frequency characterization of these RDL structures demonstrated single-ended insertion losses of −0.097 dB/mm at f = 1 GHz and differential insertion losses of −0.05 dB/mm at f = 14 GHz.

Characterization of Bacteria Signal Propagation With an Absorbing Wall

2019 ◽  
Vol 23 (4) ◽  
pp. 744-747
Author(s):  
Ankit ◽  
Manav R. Bhatnagar
Keyword(s):  
Signal Propagation

scholarly journals Electrophysiological Characterization of Human Atria: The Understated Role of Temperature

2021 ◽  
Vol 12 ◽  
Author(s):  
Rupamanjari Majumder ◽  
Afnan Nabizath Mohamed Nazer ◽  
Alexander V. Panfilov ◽  
Eberhard Bodenschatz ◽  
Yong Wang
Keyword(s):  
Action Potential ◽  
Ambient Temperature ◽  
Mild Hypothermia ◽  
Signal Propagation ◽  
Resting Membrane Potential ◽  
Influence Of Temperature On ◽  
Electrophysiological Characterization ◽  
Increasing Temperature ◽  
Important Characterization

Ambient temperature has a profound influence on cellular electrophysiology through direct control over the gating mechanisms of different ion channels. In the heart, low temperature is known to favor prolongation of the action potential. However, not much is known about the influence of temperature on other important characterization parameters such as the resting membrane potential (RMP), excitability, morphology and characteristics of the action potential (AP), restitution properties, conduction velocity (CV) of signal propagation, etc. Here we present the first, detailed, systematic in silico study of the electrophysiological characterization of cardiomyocytes from different regions of the normal human atria, based on the effects of ambient temperature (5−50°C). We observe that RMP decreases with increasing temperature. At ~ 48°C, the cells lose their excitability. Our studies show that different parts of the atria react differently to the same changes in temperature. In tissue simulations a drop in temperature correlated positively with a decrease in CV, but the decrease was region-dependent, as expected. In this article we show how this heterogeneous response can provide an explanation for the development of a proarrhythmic substrate during mild hypothermia. We use the above concept to propose a treatment strategy for atrial fibrillation that involves severe hypothermia in specific regions of the heart for a duration of only ~ 200 ms.

A Novel Approach to the Measurement and Characterization of Losses due to Surface Roughness in High Speed Transmission Lines

2011 ◽  
Vol 2011 (CICMT) ◽  
pp. 000241-000245
Author(s):  
Femi Akinwale ◽  
A. Ege Engin
Keyword(s):  
Surface Roughness ◽  
Transmission Lines ◽  
High Speed ◽  
Data Transfer ◽  
Signal Propagation ◽  
High Frequencies ◽  
Novel Approach ◽  
Critical Issues ◽  
5 Ghz

An accurate measurement technique is required to fully characterize the losses observed at high frequencies in transmission lines. Evaluation of losses seen at high frequencies is necessary to meet the high-speed data transfer rates that future applications will demand. Conductor properties and losses are two critical issues in signal path characterization. The nature of conductor losses is not well understood at high speeds. Classical models used for predicting the effects of surface roughness on signal propagation are known to breakdown around 5 GHz. Novel methods are sought to quantify the effects beyond 5 GHz. In this paper, a simple methodology to extract conductor loss is derived and validated based on a stripline configuration of two different widths. The proposed methodology is applicable to surface roughness loss characterization of both organic and ceramic packaging materials.

Electrophysiological characterization of human atria: the understated role of temperature

2020 ◽  
Author(s):  
Rupamanjari Majumder ◽  
Afnan Nabizath Mohamed Nazer ◽  
Alexander V. Panfilov ◽  
Eberhard Bodenschatz ◽  
Yong Wang
Keyword(s):  
Action Potential ◽  
Ambient Temperature ◽  
Mild Hypothermia ◽  
Signal Propagation ◽  
Resting Membrane Potential ◽  
Influence Of Temperature On ◽  
Normal Human ◽  
Electrophysiological Characterization ◽  
Increasing Temperature

ABSTRACTAmbient temperature has a profound influence on cellular electrophysiology through direct control over the gating mechanisms of different ion channels. In the heart, low temperature is known to favour prolongation of the action potential. However, not much is known about the influence of temperature on other important characterisation parameters such as the resting membrane potential (RMP), excitability, morphology and characteristics of the action potential (AP), restitution properties, conduction velocity (CV) of signal propagation, etc. Here we present the first, detailed, systematic in silico study of the electrophysiological characterization of cardiomyocytes from different regions of the normal human atria, based on the effects of ambient temperature (5 −50°C). We observe that RMP decreases with increasing temperature. At ∼ 48°C, the cells lose their excitability. Our studies show that different parts of the atria react differently to the same changes in temperature. In tissue simulations a drop in temperature correlated positively with a decrease in CV, but the decrease was region-dependent, as expected. In this article we show how this heterogeneous response can provide an explanation for the development of a proarrhythmic substrate during mild hypothermia. We use the above concept to propose a treatment strategy for atrial fibrillation that involves severe hypothermia in specific regions of the heart for a duration of only ∼ 200ms.

scholarly journals Characterization of In-Pipe Acoustic Wave for Water Leak Detection

2011 ◽  
Author(s):  
Atia E. Khalifa ◽  
Rached Ben-Mansour ◽  
Kamal Youcef-Toumi ◽  
Changrak Choi
Keyword(s):  
Acoustic Signal ◽  
Acoustic Waves ◽  
Wave Attenuation ◽  
Signal Propagation ◽  
Optimum Location ◽  
Flow Conditions ◽  
Water Leak ◽  
Flexible Pipes ◽  
Line Pressure

This paper presents experimental observations on the characteristics of the acoustic signal propagation and attenuation inside water-filled pipes. An acoustic source (exciter) is mounted on the internal pipe wall, at a fixed location, and produces a tonal sound to simulate a leak noise with controlled frequency and amplitude, under different flow conditions. A hydrophone is aligned with the pipe centerline and can be re-positioned to capture the acoustic signal at different locations. Results showed that the wave attenuation depends on the source frequency and the line pressure. High frequency signals get attenuated more with increasing distance from the source. The optimum location to place the hydrophone for capturing the acoustic signal is not at the vicinity of source location. The optimum location also depends on the frequency and line pressure. It was also observed that the attenuation of the acoustic waves is higher in more flexible pipes like PVC ones.

Design and Demonstration of Fine-Pitch and High-Speed Redistribution Layers for Panel-Based Glass Interposers at 40-μm Bump Pitch

2016 ◽  
Vol 13 (3) ◽  
pp. 128-135
Author(s):  
Brett Sawyer ◽  
Yuya Suzuki ◽  
Zihan Wu ◽  
Hao Lu ◽  
Venky Sundaram ◽  
...  
Keyword(s):  
High Speed ◽  
Metal Layer ◽  
Low Cost ◽  
Signal Propagation ◽  
Thin Glass ◽  
Fine Pitch ◽  
Data Rates ◽  
Insertion Losses ◽  
Low Permittivity

This article analyzes redistribution layer (RDL) technologies needed for 2.5-dimensional (2.5-D) die integration on thin glass interposers and developed using low-cost processes. The design, fabrication, and characterization of a four-metal layer RDL buildup required for wide input/output (I/O) routing at 40-μm bump pitch and a two-metal layer RDL buildup fabricated directly on glass for high-speed, off-package signaling are described. Such RDL technologies are targeted at 2.5-D glass interposer packages to achieve up to 1 Tb/s die-to-die bandwidth and off-interposer data rates > 400 Gb/s, driven by consumer demand of online services for mobile devices. Advanced packaging architectures including 2.5-D and 3-D interposers require fine-line lithography beyond the capabilities of current organic package substrates. High electrical loss and high cost are characteristic of silicon interposers fabricated using back-end-of-line (BEOL) processes that can achieve RDL wiring densities required for 2.5-D die integration. Organic interposers with high wiring densities have also been demonstrated using a single-sided, thin-film process. This article goes beyond silicon and organic interposers in demonstrating fine-pitch RDL on glass interposers fabricated by low-cost, double-side, and panel-scalable processes. The high modulus and smooth surface of glass help to achieve lithographic pitch close to that of silicon. Furthermore, the low permittivity and low loss tangent of glass reduce dielectric losses, thus improving high-speed signal propagation. A semiadditive process flow and projection excimer laser ablation were used to fabricate four-metal layer (2 + 0 + 2) fine-pitch RDL and two-metal layer RDL directly on glass. A minimum of 3 μm lithography and 20 μm microvia pitch was achieved. High-frequency characterization of these RDL structures demonstrated single-ended insertion losses of −0.097 dB/mm at f = 1 GHz and differential insertion losses of −0.05 dB/mm at f = 14 GHz.

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