Effect of postoperative ultrasound-guided internal superior laryngeal nerve block on sore throat after intubation of double-lumen bronchial tube: a randomized controlled double-blind trial.

BACKGROUND: Postoperative sore throat (POST) is one of the main adverse postoperative outcome after tracheal intubation using double-lumen endobronchial tubes (DLTs). The aim of this study was to investigate the effectiveness and safety of ultrasound (US)-guided block of the internal branch of the superior laryngeal nerve (iSLN) for alleviating POST after intubation of DLTs. METHODS: Patients undergoing thoracic surgery between August 2019 and August 2021 were randomized into two groups depending on whether they received US-guided iSLN block immediately after the operation. In the control group, the patients underwent a thoracic surgery under general anesthesia (GA) with DLTs without any special treatment, while the patients in the experimental group received US-guided iSLN block bilaterally with 2 ml of 0.25% ropivacaine on either side immediately after the operation. The primary outcome was the grading of sore throat at three-time points after the operation, i.e., immediate extubation, 2 h after extubation, and 24 h after extubation. Secondary outcomes included the rate of nausea and vomiting, hoarseness, dyspnea, and choking cough after swallowing saliva at 2 h after extubation. RESULTS: The incidence and severity of sore throat were significantly lower in the experimental group than the control group at all time intervals (all P < 0.01). The rate of nausea and vomiting, hoarseness, dyspnea, and choking cough after swallow saliva at 2 h after extubation had no statistical difference (all P > 0.05). CONCLUSIONS: The use of US-guided iSLN block can be effectively and safely applied to relieve POST after intubation of DLTs on thoracic surgery. TRIAL REGISTRATION: The study protocol was registered at the Chinese Clinical Trial Registry ( http://www.chictr.org.cn , NO. ChiCTR2000032188, 22/04/2020).

Refractive index sensor based on etched eccentric core few-mode fiber dual-mode interferometer.

A compact and high sensitivity refractive index (RI) sensor has been theoretically and experimentally demonstrated based on dual-mode interferometer (DMI) in an eccentric core few-mode fiber (ECFMF). The DMI is fabricated by fusion splicing a piece of ECFMF etched by hydrofluoric acid (HF) and two single mode fibers (SMFs) with a lateral-offset. The interference is formed by LP01 and LP11 modes in the eccentric core of ECFMF. The etched ECFMF-DMI based on core-core mode interference exhibits a higher RI sensitivity than the DMI based on core-cladding mode interference. The sensitivity reaches up to 2565.2 nm/RIU around the RI of 1.4. Both of the etched and unetched ECFMF-DMIs have low temperature sensitivities of 9.6 pm/°C and 33.1 pm/°C, respectively. The etched ECFMF-DMI based on the core-core mode interference possesses tremendous superiority for RI measurement due to its high RI sensitivity and low temperature cross, therefore the proposed sensor has great potentials in chemical and biological fields.

Protruding-shaped SiO2-microtip: from fabrication innovation to microphotonic device construction.

In this Letter, we first proposed a new technology to prepare protruding-shaped SiO2-microtips (PSSMs): transient spinning technology (TST). By designing the operation steps and controlling the discharge parameters of a fiber splicing machine (Furukawa S178a), the protruding-shaped SiO2-microtips with different structural parameters can be fabricated simply, quickly, and efficiently. Two kinds of microtip photonic devices were designed: (1) a high-sensitivity gas refractive index Mach-Zehnder interferometer sensor based on the coned microtip and (2) an efficient LP11-mode selective exciter based on the lensed microtip. Furthermore, the PSSMs have more potential applications, such as optical fiber tweezers, optical fiber Raman probes, and scanning near-field optical microscopy.

Cylinder-type fiber-optic Vernier probe based on cascaded Fabry-Perot interferometers with a controlled FSR ratio.

We designed a cylinder-type fiber-optic Vernier probe based on cascaded Fabry-Perot interferometers (FPIs) in this paper. It is fabricated by inserting a short single-mode fiber (SMF) column into a large-aperture hollow-core fiber (LA-HCF) with an internal diameter of 150 µm, which structures a length adjusted air microcavity with the lead-in SMF inserted into the LA-HCF from the other end. The length of the SMF column is 537.9 µm. By adjusting the distance between the SMF column and the lead-in SMF, the spectral change is displayed intuitively, and the Vernier spectra are recorded and analyzed. In sensitivity analysis, the probe is encapsulated in the medical needle by ultraviolet glue as a small body thermometer when the length of the air microcavity is 715.5 µm. The experiment shows that the sensitivity of the Vernier envelope is 12.55 times higher than that of the high-frequency comb. This design can effectively reduce the preparation difficulty of the optical fiber Vernier sensor based on cascaded FPIs, and can expand the applied fields by using different fibers and materials.

Autophagic Degradation Deficit Involved in Sevoflurane-Induced Amyloid Pathology and Spatial Learning Impairment in APP/PS1 Transgenic Mice.

The adverse effects of anesthetics on elderly people, especially those with brain diseases are very concerning. Whether inhaled anesthetics have adverse effects on Alzheimer's disease (AD), which is the most common form of dementia with brain degenerative changes, remains controversial. Autophagy, a crucial biological degradation process, is extremely important for the pathogenesis of AD. In this study, the inhaled anesthetic sevoflurane elicited many enlarged autolysosomes and impaired the overall autophagic degradation in the hippocampus of an AD mouse model, which is involved in the accumulation of amyloid-ß (Aß) and spatial learning deficits. However, rapamycin treatment counteracted all these effects. The results suggested that inhaled anesthetics may accelerate the pathological process of AD, and enlarged autolysosomes may be a new marker for prediction and diagnosis of the neurotoxicity of anesthetics in AD.

Midazolam Enhances Mutant Huntingtin Protein Accumulation via Impairment of Autophagic Degradation In Vitro.

BACKGROUND/AIMS: Autophagy is a well-known pathway to "clean" the misfolded mutant huntingtin protein (mHtt), which plays a considerable role in polyglutamine diseases. To date, there have been few studies of the choice of anesthetic during surgery in patients with polyglutamine diseases and evaluation of the effects and underlying mechanisms of anesthetics in these patients. METHODS: GFP-Htt (Q74)-PC12 cells, which stably express green fluorescent protein-tagged Htt protein containing 74 glutamine repeating units, were used throughout this study. Cells were treated with 15 µM midazolam and 100 mM trehalose (positive control), and the induction of autophagy and autophagic degradation were assessed by detecting changes in autophagy-related proteins and substrates, and cell viability was assessed using the MTT assay. Overexpression of cathepsin D by plasmid transfection was used to restore midazolam-impaired autophagic degradation. RESULTS: Midazolam increased intracellular mHtt levels in a time- and dose-dependent manner. Additionally, enhancing or blocking autophagic flux by trehalose or chloroquine could decrease or increase midazolam-induced mHtt elevation, respectively. Midazolam induced autophagy in the mTOR-dependent signaling pathway, but autophagic degradation was impaired, with a continuous rise in p62 and LC3 II levels and decrease in cathepsin D. However, overexpression of cathepsin D reversed the effects of midazolam. Midazolam led to a 20% decrease in GFP-Htt (Q74)-PC12 cell viability, which could be abrogated by overexpression of cathepsin D. CONCLUSIONS: Midazolam increased mHtt levels and decreased Htt (Q74)-PC12 cell viability via impairment of autophagic degradation, which could be restored by overexpression of cathepsin D.

Intensity-demodulated torsion sensor based on thin-core polarization-maintaining fiber.

An intensity-demodulated torsion sensor is designed and realized, which consists of a polarization ring as the sensing part and a section of thin-core polarization-maintaining fiber as the demodulation part. An intensity map of a sinusoidal change can be obtained at some specific wavelengths, and the experimental results correspond to the theoretical analysis well. The maximum sensitivity is about 0.29 dB/deg at the wavelength of 1584.6 nm, and the minimum sensitivity is about 0.10 dB/deg at the wavelength of 1510.2 nm. Meanwhile, the temperature characteristic is measured in the experiment. More broadly, the proposed structure can be used in an integrated smart device for loose-screw detection in devices in aeronautics and astronautics.

Two-dimensional microbend sensor based on long-period fiber gratings in an isosceles triangle arrangement three-core fiber.

To realize the 2D microbend sensor, we design and fabricate two non-orthogonal long-period fiber gratings (LPFGs) in an isosceles triangle arrangement three-core optical fiber which is made in our lab, making an isosceles triangle arrangement three-core optical fiber. To mark two directions without crosstalk, we write two different periods of LPFG in each of the two external cores and the central core, which induces a strong asymmetric refractive index arrangement in the fiber cross section. Theoretical analysis and experimental results verify that the resonant wavelength originates from the tunneling between the LP01 core mode in the center core and the external core. In the confirmation experiments, the proposed sensor can distinguish multiple bending directions and experiences a maximum sensitivity of 3.234 nm/m-1 with a bending range of 0-0.588 m-1.

Concave-lens-like long-period fiber grating bidirectional high-sensitivity bending sensor.

A novel bidirectional high-sensitivity fiber-optic bending sensor based on the concave-lens-like long-period fiber grating (CLL-LPFG) is designed and demonstrated. The CLL-LPFG is composed by an array of arc-shaped grating planes, and accordingly, its refractive index modulation serves as a concave lens. As a result, the eigencladding mode of the device gets closer to the device surface than the conventional counterpart. Therefore, the proposed sensor provides a more sensitive result. The experimental results show that the bending sensitivities of the CLL-LPFG reach -32.782 nm/m-1 within the bending range of 0-2.08 m-1, which is about sixfold compared to the reported arts. The sensitivity can be potentially improved by optimizing the grating parameters, and the temperature characteristics of the CLL-LPFG can be used to manipulate the grating spectrum.

Realizing torsion detection using berry phase in an angle-chirped long-period fiber grating.

We demonstrate the fabrication of an angle-chirped long-period fiber grating (ACLPFG) in a single-mode fiber via CO2 laser pulses. Because of the Berry phase introduced by the ACLPFG, the interference acquires an extra phase difference determined by the torsion of the device. By using that unique characteristic of the proposed device, a high sensitivity sine function torsion response is achieved. The torsion sensitivity is significantly improved, and the temperature crosstalk is effectively avoided by using the relative measurement technology. The torsion sensitivity is ~16 folds (~0.94 nm/ (rad/m)) higher than that of the normal long-period fiber grating (LPFG) with only ~0.006 nm/°C temperature crosstalk within the range of 25-80 °C, which is ~10 folds lower than that of the normal LPFG.

Fiber in-line Mach-Zehnder interferometer based on near-elliptical core photonic crystal fiber for temperature and strain sensing.

A fiber in-line Mach-Zehnder interferometer is fabricated by selectively filling liquid into one air hole of the innermost layer of a photonic crystal fiber (PCF). The refractive index of the liquid is so close to that of the background silica in the wavelength range of 1300-1600 nm that the two-mode PCF evolves into multimode PCF with an elliptically shaped core. Due to the different propagation constants, interference can occur between the fundamental mode and higher-order modes of the liquid-filled PCF. Such a device is applied in temperature and strain measurements with high sensitivities of 16.49 nm/°C and -14.595 nm/N, respectively.

Simultaneous measurement of temperature and force with high sensitivities based on filling different index liquids into photonic crystal fiber.

A double-filled photonic crystal fiber (PCF) was fabricated by filling liquids of different indexes into two air holes in the cladding. The core mode coupled to the local cladding modes LP(01) and LP(11) in the 1310 and 1550 nm wavebands, respectively. Due to the unique characteristics of the mode coupling, the resonant peaks in different resonance areas shifted to the opposite directions with the variations of the temperature or the force. The double-filled PCFs achieved in this work showed useful applications in the simultaneous measurement of both the temperature and the force.

Two-dimensional bending vector sensing based on spatial cascaded orthogonal long period fiber.

A novel bending vector sensor based on spatial cascaded orthogonal long period fiber gratings (SCO-LPFGs) written by high-frequency CO(2) laser pulses has been proposed, and two-dimensional bending vector sensing characteristics based on the simple SCO-LPFGs have been experimentally demonstrated. A three-dimensional orthogonal sensing coordinate system has been established, and the measurement results of the proposed SCO-LPFGs sensor based on the above coordinate system is given, and furthermore both of curvature and bending-direction could be intuitively solved according to the three-dimensional orthogonal sensing coordinates. The research work presented in this paper would be helpful to improve the practicability of fiber vector sensors due to the distinguished characteristics such as simple structure, low-cost, ease of fabrication.

Fiber-optic bending vector sensor based on Mach-Zehnder interferometer exploiting lateral-offset and up-taper.

A simple, compact, and highly sensitive optical fiber directional bend sensor is presented. This device consists of a lateral-offset splicing joint and an up-taper formed through excessive fusion splicing method. The lateral-offset splicing breaks the cylindrical symmetry of the fiber and defines a pair of directions along which the bending response of the Mach-Zehnder interferometer transmission spectrum is different and thus could be used for bending vector measurement. For a curvature range from -3 to 3 m(-1), the bending sensitivities at 1463.86 nm and 1548.41 nm reach 11.987 nm/m(-1) and 8.697 nm/m(-1), respectively.

Design of single-polarization wavelength splitter based on photonic crystal fiber.

A new single-polarization wavelength splitter based on the photonic crystal fiber (PCF) has been proposed. The full-vector finite-element method (FEM) is applied to analyze the single-polarization single-mode guiding properties. Splitting of two different wavelengths is realized by adjusting the structural parameters. The semi-vector three-dimensional beam propagation method is employed to confirm the wavelength splitting characteristics of the PCF. Numerical simulations show that the wavelengths of 1.3 µm and 1.55 µm are split for a fiber length of 10.7 mm with single-polarization guiding in each core. The crosstalk between the two cores is low over appreciable optical bandwidths.