다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Skin plays an important role in mediating our interactions with the world. Recreating the properties of skin using electronic devices could have profound implications for prosthetics and medicine. The pursuit of artificial skin has inspired innovations in materials to imitate skin's unique characteristics, including mechanical durability and stretchability, biodegradability, and the ability to measure a diversity of complex sensations over large areas. New materials and fabrication strategies are being developed to make mechanically compliant and multifunctional skin-like electronics, and improve brain/machine interfaces that enable transmission of the skin's signals into the body. This Review will cover materials and devices designed for mimicking the skin's ability to sense and generate biomimetic signals.

Pursuing prosthetic electronic skin.

When mounted on the skin, modern sensors, circuits, radios, and power supply systems have the potential to provide clinical-quality health monitoring capabilities for continuous use, beyond the confines of traditional hospital or laboratory facilities. The most well-developed component technologies are, however, broadly available only in hard, planar formats. As a result, existing options in system design are unable to effectively accommodate integration with the soft, textured, curvilinear, and time-dynamic surfaces of the skin. Here, we describe experimental and theoretical approaches for using ideas in soft microfluidics, structured adhesive surfaces, and controlled mechanical buckling to achieve ultralow modulus, highly stretchable systems that incorporate assemblies of high-modulus, rigid, state-of-the-art functional elements. The outcome is a thin, conformable device technology that can softly laminate onto the surface of the skin to enable advanced, multifunctional operation for physiological monitoring in a wireless mode.

http://science.sciencemag.org/content/sci/344/6179/70.full.pdf

Soft Microfluidic Assemblies of Sensors, Circuits, and Radios for the Skin

Due to limitations of low power density, high cost, heavy weight, etc., the development and application of battery-powered devices are facing with unprecedented technical challenges. As a novel pattern of energization, the wireless power transfer (WPT) offers a band new way to the energy acquisition for electric-driven devices, thus alleviating the over-dependence on the battery. This paper presents an overview of WPT techniques with emphasis on working mechanisms, technical challenges, metamaterials, and classical applications. Focusing on WPT systems, this paper elaborates on current major research topics and discusses about future development trends. This novel energy transmission mechanism shows significant meanings on the pervasive application of renewable energies in our daily life.

Wireless Power Transfer—An Overview

Small, lightweight LED implants and a radio-frequency transducer as a power source enable wireless optogenetic stimulation in the brain, spinal cord and peripheral nervous system of behaving mice.

/pdf/wirelessly-powered-fully-internal-optogenetics-for-brain-22zisrey9s.pdf

Wirelessly powered, fully internal optogenetics for brain, spinal and peripheral circuits in mice

The ability to implant electronic systems in the human body has led to many medical advances. Progress in semiconductor technology paved the way for devices at the scale of a millimeter or less (“microimplants”), but the miniaturization of the power source remains challenging. Although wireless powering has been demonstrated, energy transfer beyond superficial depths in tissue has so far been limited by large coils (at least a centimeter in diameter) unsuitable for a microimplant. Here, we show that this limitation can be overcome by a method, termed midfield powering, to create a high-energy density region deep in tissue inside of which the power-harvesting structure can be made extremely small. Unlike conventional near-field (inductively coupled) coils, for which coupling is limited by exponential field decay, a patterned metal plate is used to induce spatially confined and adaptive energy transport through propagating modes in tissue. We use this method to power a microimplant (2 mm, 70 mg) capable of closed-chest wireless control of the heart that is orders of magnitude smaller than conventional pacemakers. With exposure levels below human safety thresholds, milliwatt levels of power can be transferred to a deep-tissue (>5 cm) microimplant for both complex electronic function and physiological stimulation. The approach developed here should enable new generations of implantable systems that can be integrated into the body at minimal cost and risk.

https://www.pnas.org/content/pnas/111/22/7974.full.pdf

Wireless power transfer to deep-tissue microimplants

Efficient wireless power transfer across tissue is highly desirable for removing bulky energy storage components. Most existing power transfer systems are conceptually based on coils linked by slowly varying magnetic fields (less than 10 MHz). These systems have many important capabilities, but are poorly suited for tiny, millimeter-scale implants where extreme asymmetry between the source and the receiver results in weak coupling. This paper first surveys the analysis of near-field power transfer and associated strategies to optimize efficiency. It then reviews analytical models that show that significantly higher efficiencies can be obtained in the electromagnetic midfield. The performance limits of such systems are explored through optimization of the source, and a numerical example of a cardiac implant demonstrates that millimeter-sized devices are feasible.

https://web.stanford.edu/group/poongroup/cgi-bin/wordpress/wp-content/uploads/2013/05/PIEEE%202013%20Ho.pdf

Midfield Wireless Powering for Implantable Systems

Wireless networks of sensors, displays and smart devices that can be placed on a person’s body could have applications in health monitoring, medical interventions and human–machine interfaces. Such wireless body networks are, however, typically energy-inefficient and vulnerable to eavesdropping because they rely on radio-wave communications. Here, we report energy-efficient and secure wireless body sensor networks that are interconnected through radio surface plasmons propagating on metamaterial textiles. The approach uses clothing made from conductive fabrics that can support surface-plasmon-like modes at radio communication frequencies. Our body sensor networks enhance transmission efficiencies by three orders of magnitude compared to conventional radiative networks without the metamaterial textile, and confine wireless communication to within 10 cm of the body. We also show that the approach can offer wireless power transfer that is robust to motion and textile-based wireless touch sensing. Energy-efficient and secure wireless body sensor networks can be created by using conductive fabrics that support surface-plasmon-like modes at radio communication frequencies.

John S. Ho

Papers

Wirelessly powered, fully internal optogenetics for brain, spinal and peripheral circuits in mice

Wireless power transfer to deep-tissue microimplants

Midfield Wireless Powering for Implantable Systems

Wireless body sensor networks based on metamaterial textiles

Biomimetic MXene Textures with Enhanced Light‐to‐Heat Conversion for Solar Steam Generation and Wearable Thermal Management