Coherently parallel fiber-optic distributed acoustic sensing using dual Kerr soliton microcombs.

Fiber-optic distributed acoustic sensing (DAS) has proven to be a revolutionary technology for the detection of seismic and acoustic waves with ultralarge scale and ultrahigh sensitivity, and is widely used in oil/gas industry and intrusion monitoring. Nowadays, the single-frequency laser source in DAS becomes one of the bottlenecks limiting its advance. Here, we report a dual-comb-based coherently parallel DAS concept, enabling linear superposition of sensing signals scaling with the comb-line number to result in unprecedented sensitivity enhancement, straightforward fading suppression, and high-power Brillouin-free transmission that can extend the detection distance considerably. Leveraging 10-line comb pairs, a world-class detection limit of 560 fε/√Hz@1 kHz with 5 m spatial resolution is achieved. Such a combination of dual-comb metrology and DAS technology may open an era of extremely sensitive DAS at the fε/√Hz level, leading to the creation of next-generation distributed geophones and sonars.

Synthesis, Crystal Structures, and Antimicrobial and Antitumor Studies of Two Zinc(II) Complexes with Pyridine Thiazole Derivatives.

Two pyridine thiazole derivatives, namely, 4-(pyridin-2-yl)-2-(2-(pyridin-2-ylmethylene)hydrazinyl)thiazole (L1) and 4-(pyridin-3-yl)-2-(2-(pyridin-4-ylmethylene)hydrazinyl)thiazole (L2), were afforded by a cyclization reaction between α-haloketone and thioamide, and their Zn(II) complexes were prepared by the reaction of ligands and corresponding metal salts, respectively, and characterized by X-ray diffraction and elemental analysis. Both crystals were obtained by ether diffusion and crystallized in a monoclinic system. The in vitro antimicrobial activity of the Zn(II) complexes and ligands was screened using the microplate reader method, and in vitro antitumor activities of the complexes were evaluated by MTT, with a view to developing new improved bioactive materials with novel properties. The biological activity studies of the compounds showed that the metal complexes were more active than the free ligands, and some compounds had absolute specificity for certain bacteria or cancer cell lines.

Effect analysis on high-flow nasal cannula for typeⅠrespiratory failure in adults / 中国医师杂志

Objective:To evaluate the efficacy and related factors of high-flow nasal cannula (HFNC) for the treatment of adult typeⅠ respiratory failure.Methods:The medical records of the subjects with acute hypoxemic respiratory failure supported by HFNC therapy in the medical intensive care unit between October 2017 and February 2019 were reviewed retrospectively. The patients′ baseline characteristics and the serial changes in the respiratory parameters after HFNC therapy at 1 and 24 hours were measured. Therapy success was defined as the avoidance of intubation. The subjects were divided into two groups.Results:Of the 75 eligible patients, 62.7%(47/75) belonged to success group. Overall, HFNC therapy significantly improved the physiologic parameters, such as partial pressure of arterial oxygen (PaO 2), saturation of arterial oxygen (SaO 2), respiratory rate (RR), and heart rate (HR), throughout the first 24 hours. After the adjustment for the other clinical variables, acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ), sequential organ failure assessment (SOFA), cardiogenic pulmonary edema, and PaO 2 improvement at 1 and 24 hours were associated with therapy success. The overall intensive mortality was 25.3%. However, out of 37.3% of the patients who required belonged to failure group, the mortality was 67.9%. The mortality in the failure group was associated with the use of a vasopressor and a limited PaO 2 improvement at 1 hour. Conclusions:HFNC can significantly improve the physiological parameters of adult patients with acute type I respiratory failure and avoid endotracheal intubation in some patients. The failure to improve oxygenation within 24 hours was a useful predictor of intubation. Among the failure group, the vasopressor use and failed oxygenation improvement were associated with mortality.

Willis covered stent in the treatment of traumatic carotid cavernous fistulae:a report of 7 cases / 国际脑血管病杂志

Objective To evaluate the efficacy and safety of Willis covered stent in the treatment of traumatic carotid cavernous fistulae (tCCF).Methods The imaging and clinical data of 7 patients with tCCF treated with Willis covered stent in Shanghai Punan Hospital from November 2015 to June 2018 were analyzed retrospectively.Results Seven Willis covered stent were used in 7 patients.Immediately after stent release,angiography showed that the fistulae completely disappeared in 6 cases.One patient had a small amount of endoleak,and there was still a small amount of endoleaks after balloon dilatation.It was not further treated.There were no operative complications.During 3-12 months follow-up,no new neurological deficits were found in all patients.Angiographic follow-up of 2 patients showed that the fistulae completely disappeared without recurrence.The internal carotid arteries were patent,no in-stent stenosis and stent displacement.Conclusions Wills covered stent can be used as a treatment for tCCF.Its efficacy is satisfactory and the safety is good.

Hybrid LPFG/MEFPI sensor for simultaneous measurement of high-temperature and strain.

A hybrid fiber-optic sensor consisting of a long-period fiber grating (LPFG) and a micro extrinsic Fabry-Perot (F-P) interferometric (MEFPI) sensor is proposed and demonstrated for simultaneous measurement of high-temperature and strain. The LPFG written by using high-frequency CO(3+) laser pulses is used for high-temperature measurement while the MEFPI sensor fabricated by using 157nm F(2) laser pulses is used for strain measurement under high temperature. The distinguishing feature of such a hybrid fiber-optic sensor is that it can stand for high temperature of up to 650 masculineC and achieve precise measurement of strain under high temperature conditions simultaneously.

Light coupling between two parallel CO2-laser written long-period fiber gratings.

We demonstrate experimentally the light coupling effects between two parallel CO(2)-laser written long-period fiber gratings. For gratings written in standard single-mode fibers, the coupling efficiency depends strongly on the fiber orientation with the strongest coupling obtained when the exposed sides of the fibers face each other, while for gratings written in boron-doped fibers, the coupling efficiency is independent of the fiber orientation. We achieve a peak coupling efficiency of approximately 86% with gratings written in boron-doped fibers by using a suitable surrounding refractive index and offset distance between the two gratings. Our results suggest the possibility of realizing efficient broadband all-fiber couplers with CO(2)-laser written long-period fiber gratings.

Long-distance fiber Bragg grating sensor system with a high optical signal-to-noise ratio based on a tunable fiber ring laser configuration.

A novel tunable fiber ring laser configuration with a combination of bidirectional Raman amplification and dual erbium-doped fiber (EDF) amplification is proposed for realizing high optical signal-to-noise ratio (SNR), long-distance, quasi-distributed fiber Bragg grating (FBG) sensing systems with large capacities and low cost. The hybrid Raman-EDF amplification configuration arranged in the ring laser can enhance the optical SNR of FBG sensor signals significantly owing to the good combination of the high gain of the erbium-doped fiber amplifier (EDFA) and the low noise of the Raman amplification. Such a sensing system can support a large number of FBG sensors because of the use of a tunable fiber Fabry-Perot filter located within the ring laser and spatial division multiplexing for expansion of sensor channels. Experimental results show that an excellent optical SNR of approximately 60 dB has been achieved for a 50 km transmission distance with a low Raman pump power of approximately 170 mW at a wavelength of 1455 nm and a low EDFA pump power of approximately 40 mW at a wavelength of 980 nm, which is the highest optical SNR achieved so far for a 50 km long FBG sensor system, to our knowledge.