There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

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

The discovery of Toll-like receptors (TLRs) as components that recognize conserved structures in pathogens has greatly advanced understanding of how the body senses pathogen invasion, triggers innate immune responses and primes antigen-specific adaptive immunity. Although TLRs are critical for host defense, it has become apparent that loss of negative regulation of TLR signaling, as well as recognition of self molecules by TLRs, are strongly associated with the pathogenesis of inflammatory and autoimmune diseases. Furthermore, it is now clear that the interaction between TLRs and recently identified cytosolic innate immune sensors is crucial for mounting effective immune responses. Here we describe the recent advances that have been made by research into the role of TLR biology in host defense and disease.

/pdf/the-role-of-pattern-recognition-receptors-in-innate-immunity-39y77tlxza.pdf

The role of pattern-recognition receptors in innate immunity: update on Toll-like receptors

Catalysts for oxygen reduction and evolution reactions are at the heart of key renewable-energy technologies including fuel cells and water splitting. Despite tremendous efforts, developing oxygen electrode catalysts with high activity at low cost remains a great challenge. Here, we report a hybrid material consisting of Co₃O₄ nanocrystals grown on reduced graphene oxide as a high-performance bi-functional catalyst for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Although Co₃O₄ or graphene oxide alone has little catalytic activity, their hybrid exhibits an unexpected, surprisingly high ORR activity that is further enhanced by nitrogen doping of graphene. The Co₃O₄/N-doped graphene hybrid exhibits similar catalytic activity but superior stability to Pt in alkaline solutions. The same hybrid is also highly active for OER, making it a high-performance non-precious metal-based bi-catalyst for both ORR and OER. The unusual catalytic activity arises from synergetic chemical coupling effects between Co₃O₄ and graphene.

/pdf/co3o4-nanocrystals-on-graphene-as-a-synergistic-catalyst-for-17jj12png6.pdf

Co3O4 nanocrystals on graphene as a synergistic catalyst for oxygen reduction reaction

CA : A Cancer Journal for Clinicians

We developed a photothermal interferometry-based trace gas sensor by coupling a mid-infrared pump laser and a near-infrared probe laser into a hollow-core optical fiber.

Mid-infrared photothermal interferometric gas sensing in hollow-core optical fibers

The invention provides an electrochemical treatment method for an arsenic poisoning catalyst. The electrochemical treatment method comprises: (1) mixing an alkali and a solvent or mixing an alkali solution and an arsenic poisoning catalyst to obtain a mixture; (2) placing the mixture as an electrolyte in an electrochemical reaction device, carrying out an electrochemical reaction, and introducingan oxidizing gas into the electrolyte during the electrochemical reaction; and (3) carrying out solid-liquid separation on the reaction product obtained in the step (2) to obtain the arsenic-containing solution. According to the present invention, the method has advantages of high extraction rate of arsenic, cleaning property, no pollution, mild process condition, low cost and low requirements onequipment; the impurity is not introduced so as to conveniently perform the subsequent separation; the concentration of the used alkali is low so as to reduce the alkali consumption; and the automation degree is high so as to reduce the manpower input, the good economic and social benefits can be provided, and the good application prospect can be provided.

Electrochemical treatment method for an arsenic poisoning catalyst

A modified fiber-optic Sagnac interferometer with a stable /2 phase bias is demonstrated for the demodulation of diaphragm-based acoustic sensors. The phase bias is obtained by introducing a nonreciprocal frequency shift between the counter-propagating waves. The system is passive and without complicated servo-control for phase stabilization. Interrogated by the proposed demodulation system, a 100 nm-thick graphite diaphragm-based acoustic sensor demonstrated a minimum detectable pressure level of ~ 450 µPa/Hz 1/2 at the frequency of 5 kHz and the output signal stability is less than 0.35 dB over an 8-hour period. Keywords: Optical fiber sensor, Sagnac interferomete r, acoustic sensor, graphite diaphragm 1. INTRODUCTION Diaphragm based fiber Fabry-Perot interferometers (FPIs) with a deflectable diaphragm attach ed to a hollow cavity have been investigated extensively for acoustic detection [1-4]. These FPI acoustic sensors are conventionally demodulated by using a narrow-band laser with the wavelength tuned to a quadrature point (Q-point) of the interference spectrum. However, the dependence of the Q-point of a FPI on the cavity-length and the difficulty of the fabrication of fiber FPIs with exactly the same cavity length mean that, for different sensors, the laser wavelength need to be tuned to different values to ensure optimal phase to intensity conversion. Furthermore, the Q-point of the sensors may drift due to fluctuation in ambient temperature and background pressure during operation, causing instability of the demodulation system. Methods such as electrical feedba ck and diffractive grating control have been employed to follow the drift and maintain the Q-point in real time but the active control increases the complexity of the system [5, 6]. In this paper, we report a stable phase demodulation system for diaphragm-based reflection-type acoustic sensors. It is based on a modified Sagnac interferometer which the sensor is incorporated into and functions as part of the Sagnac loop by using an additional fiber directional coupler. Stable phase bias is achieved by inducing a nonreciprocal frequency shift between the two counter-propagating waves in the modified Sagnac interferometer. The system could be used for universal phase demodulation of diaphragm-based acoustic sensors as well as other reflection-type sensors.

Sagnac interferometer based stable phase demodulation system for diaphragm based acoustic sensor

The acoustic pressure sensitivities of hollow-core photonic bandgap fibers (HC-PBFs) with different thicknesses of silica outer-cladding and polymer jacket were experimentally investigated. Experiment with a HC-PBF with 7 μm-thick silica outer cladding and 100 μm-thick Parylene C jacket demonstrated a pressure sensitivity 10 dB higher than the commercial HC-1550-02 fiber and 25 dB higher than a standard single mode fiber. The significant enhancement in sensitivity would simplify the design of fiber hydrophones and increase the number of sensors that could be multiplexed in a single fiber.

Investigation of acoustic sensitivity of hollow-core photonic bandgap fibers

We report the results of our recent investigation on acoustically-induced mode-coupling in few-mode photonic crystal fibers. The potential applications of such acousto-optic devices in tunable optical filters, switches and interferometric sensors will be discussed.

Wei Jin

Papers

Mid-infrared photothermal interferometric gas sensing in hollow-core optical fibers

Electrochemical treatment method for an arsenic poisoning catalyst

Sagnac interferometer based stable phase demodulation system for diaphragm based acoustic sensor

Investigation of acoustic sensitivity of hollow-core photonic bandgap fibers

Acoustically-induced mode-coupling in photonic crystal fibers