Detection of Single Nucleotide Polymorphisms of Circulating Tumor DNA by Strand Displacement Amplification Coupled with Liquid Chromatography.

The detection of multiple single nucleotide polymorphisms (SNPs) of circulating tumor DNA (ctDNA) is still a great challenge. In this study, we designed enzyme-assisted nucleic acid strand displacement amplification combined with high-performance liquid chromatography (HPLC) for the simultaneous detection of three ctDNA SNPs. First, the trace ctDNA could be hybridized to the specially designed template strand, which initiated the strand displacement nucleic acid amplification process under the synergistic action of DNA polymerase and restriction endonuclease. Then, the targets would be replaced with G-quadruplex fluorescent probes with different tail lengths. Finally, the HPLC-fluorescence assay enabled the separation and quantification of multiple signals. Notably, this method can simultaneously detect both the wild type (WT) and mutant type (MT) of multiple ctDNA SNPs. Within a linear range of 0.1 fM-0.1 nM, the detection limits of BRAF V600E-WT, EGFR T790M-WT, and KRAS 134A-WT and BRAF V600E-MT, EGFR T790M-MT, and KRAS 134A-MT were 29, 31, and 11 aM and 22, 29, and 33 aM, respectively. By using this method, the mutation rates of multiple ctDNA SNPs in blood samples from patients with lung or breast cancer can be obtained in a simple way, providing a convenient and highly sensitive analytical assay for the early screening and monitoring of lung cancer.

Evaluation of activities of daily living using an electronic version of the Longshi Scale in patients with stroke: reliability, consistency, and preference.

BACKGROUND: The Longshi Scale is a pictorial assessment tool for evaluating activities of daily living (ADL) in patients with stroke. The paper-based version presents challenges; thus, the WeChat version was created to enhance accessibility. Herein, we aimed to validate the inter-rater and test-retest reliabilities of the WeChat version of the Longshi Scale and explore its potential clinical applications. METHODS: We recruited 115 patients with stroke in the study. The ADL results of each patient were assessed using both the WeChat and paper-based version of the Longshi Scale; each evaluation was conducted by 28 health professionals and 115 caregivers separately. To explore the test-retest reliability of the WeChat version, 22 patients were randomly selected and re-evaluated by health professionals using the WeChat version. All evaluation criteria were recorded, and all evaluators were surveyed to indicate their preference between the two versions. RESULTS: Consistency between WeChat and the paper-based Longshi Scale was high for ADL scores by health professionals (ICC2,1 = 0.803-0.988) and caregivers (ICC2,1 = 0.845-0.983), as well as for degrees of disability (κw = 0.870 by professionals; κw = 0.800 by caregivers). Bland-Altman analysis showed no significant discrepancies. The WeChat version exhibited good test-retest reliability (κw = 0.880). The WeChat version showed similar inter-rater reliability in terms of the ADL score evaluated using the paper-based version (ICC2,1 = 0.781-0.941). The time to complete assessments did not differ significantly, although the WeChat version had a shorter information entry time (P < 0.001, 95% confidence interval: -43.463 to -15.488). Health professionals favored the WeChat version (53.6%), whereas caregivers had no significant preference. CONCLUSIONS: The WeChat version of the Longshi Scale is reliable and serves as a suitable alternative for health professionals and caregivers to assess ADL levels in patients with stroke. The WeChat version of the Longshi Scale is considered user-friendly by health professionals, although it is not preferred by caregivers. TRIAL REGISTRATION: This study was approved by the Ethics Committee of the Second People's Hospital of Shenzhen (approval number: 20210812003-FS01) and registered on the Clinical Trial Register Center website: clinicaltrials.gov on January 31, 2022 (registration no.: NCT05214638).

Production of extracellular vesicles from equine embryo-derived mesenchymal stromal cells.

In brief: Mesenchymal stromal cell (MSC)-derived extracellular vesicles (EVs) have shown promise as off-the-shelf therapeutics; however, producing them in sufficient quantities can be challenging. In this study, MSCs were isolated from preimplantation equine embryos and used to produce EVs in two commercially available bioreactor designs. Abstract: Mesenchymal stromal cells (MSC) have recently been explored for their potential use as therapeutics in human and veterinary medicine applications, such as the treatment of endometrial inflammation and infertility. Allogeneic MSC-derived extracellular vesicles (EVs) may also provide therapeutic benefits with advantage of being an 'off-the-shelf' solution, provided they can be produced in large enough quantities, without contamination from bovine EVs contained in fetal bovine serum that is a common component of cell culture media. Toward this aim, we demonstrated the successful isolation and characterization of equine MSCs from preimplantation embryos. We also demonstrate that many of these lines can be propagated long-term in culture while retaining their differentiation potential and conducted a head-to-head comparison of two bioreactor systems for scalable EV production including in serum-free conditions. Based on our findings, the CELLine AD 1000 flasks enabled higher cell density cultures and significantly more EV production than the FiberCell system or conventional culture flasks. These findings will enable future isolation of equine MSCs and the scalable culture of their EVs for a wide range of applications in this rapidly growing field.

Does orbital angular momentum have effect on laser's scattering by molecular atmosphere?

Lasers with orbital angular momentum (OAM) have potential applications in communication technology, manipulation of particles, and remote sensing. Because of its unusual light-scattering properties, the OAM laser's interaction with a molecular atmosphere must be studied to ensure that it is not lossy for communication or remote-sensing applications that involve its transmission through an atmospheric environment. In this study, the finite-difference time-domain (FDTD) method [21] is applied to calculate the light scattering of the purely azimuthal (the radial mode number is assumed to be zero) Laguerre-Gaussian (LG) beams with OAM by very small dielectric particles. Not like Lorentz-Mie solutions, the FDTD method can calculate for particles off the central axis of the LG beam. It is found that when the particles are very small, and the topological charge number of the OAM of a laser is not extremely large, the laser's OAM has little effect on the scattering phase function. This suggests that Rayleigh theory can be applied directly to calculate the light scattering by atmospheric molecules. The transmission of a laser beam with OAM in a molecular atmosphere is not different from that of a regular Gaussian beam.

Introducing SiTTE: A controlled laboratory setting to study the impact of turbulent fluctuations on light propagation in the underwater environment.

Small-scale spatial variation in temperature can lead to localized changes in the index of refraction and can distort electro-optical (EO) signal transmission in ocean and atmosphere. This phenomenon is well-studied in the atmosphere, where it is generally called "optical turbulence". Less is known about how turbulent fluctuations in the ocean distort EO signal transmissions, an effect that can impact various underwater applications, from diver visibility to active and passive remote sensing. To provide a test bed for the study of the impacts from turbulent flows on EO signal transmission, and to examine and mitigate turbulence effects, we set up a laboratory turbulence environment allowing the controlled and repeatable variation of turbulence intensity. The laboratory measurements are complemented by high resolution computational fluid dynamics simulations emulating the tank environment. This controlled Simulated Turbulence and Turbidity Environment (SiTTE) can be used to assess optical image degradation in the tank in relation to turbulence intensity, as well as to examine various adaptive optics mitigation techniques.

Self-gauged fiber-optic micro-heater with an operation temperature above 1000°C.

We report a fiber-optic micro-heater based on a miniature crystalline silicon Fabry-Perot interferometer (FPI) fusion spliced to the endface of a single-mode fiber. The silicon FPI, having a diameter of 100 µm and a length of 10 or 200 µm, is heated by a 980 nm laser diode guided through the lead-in fiber, leading to a localized hot spot with a temperature that can be conveniently tuned from the ambient temperature to >1000°C in air. In the meantime, using a white light system operating in the 1550 nm wavelength window where the silicon is transparent, the silicon FPI itself also serves as a thermometer with high resolution and high speed for convenient monitoring and precise control of the heater temperature. Due to its small size, high temperature capability, and easy operation, the micro-heater is attractive for applications in a variety of fields, such as biology, microfluidics system, mechanical engineering, and high-temperature optical sensing. As an example, the application of this micro-heater as a micro-boiler and micro-bubble generator has been demonstrated.

Experimental and numerical study of underwater beam propagation in a Rayleigh-Bénard turbulence tank.

The propagation of a laser beam through Rayleigh-Bénard (RB) turbulence is investigated experimentally and by way of numerical simulation. For the experimental part, a focused laser beam transversed a 5 m×0.5 m×0.5 m water filled tank lengthwise. The tank is heated from the bottom and cooled from the top to produce convective RB turbulence. The effect of the turbulence on the beam is recorded on the exit of the beam from the tank. From the centroid motion of the beam, the index of refraction structure constant Cn2 is determined. For the numerical efforts RB turbulence is simulated for a tank of the same geometry. The simulated temperature fields are converted to the index of refraction distributions, and Cn2 is extracted from the index of refraction structure functions, as well as from the simulated beam wander. To model the effect on beam propagation, the simulated index of refraction fields are converted to discrete index of refraction phase screens. These phase screens are then used in a split-step beam propagation method to investigate the effect of the turbulence on a laser beam. The beam wander as well as the index of refraction structure parameter Cn2 determined from the experiment and simulation are compared and found to be in good agreement.

Influence of fiber bending on wavelength demodulation of fiber-optic Fabry-Perot interferometric sensors.

In practical applications of fiber optic sensors based on Fabry-Perot interferometers (FPIs), the lead-in optical fiber often experiences dynamic or static bending due to environmental perturbations or limited installation space. Bending introduces wavelength-dependent losses to the sensors, which can cause erroneous readings for sensors based on wavelength demodulation interrogation. Here, we investigate the bending-induced wavelength shift (BIWS) to sensors based on FPIs. Partially explicit expressions of BIWSs for the reflection fringe peaks and valleys have been derived for sensors based on low-finesse FPI. The theoretical model predicts these findings: 1) provided that a fringe peak experiences the same modulation slope by bending losses with a fringe valley, BIWSs for the peak and valley have opposite signs and the BIWS for the valley has a smaller absolute value; 2) BIWS is a linear function of the length of the bending section; 3) a FPI with higher visibility and longer optical path length is more resistant to the influence of bending. Experiments have been carried out and the results agree well with the theoretical predictions.

Optical fiber vector flow sensor based on a silicon Fabry-Perot interferometer array.

We report a miniature fiber-optic water vector flow sensor based on an array of silicon Fabry-Perot interferometers (FPIs). The flow sensor is composed of four silicon FPIs, one in the center with the other three equally distributed around it. The center FPI is heated by a cw laser at 980 nm, which is guided through the lead-in single mode fiber. The temperature structure established within the sensor head due to laser heating is a function of the flow vector (speed and direction), which can be deduced from the wavelength shifts of the four FPIs. Theoretical analysis has been conducted to illustrate the operating principle and experimental demonstration has been provided.

High-resolution, large dynamic range fiber-optic thermometer with cascaded Fabry-Perot cavities.

The paradox between a large dynamic range and a high resolution commonly exists in nearly all kinds of sensors. Here, we propose a fiber-optic thermometer based on dual Fabry-Perot interferometers (FPIs) made from the same material (silicon), but with different cavity lengths, which enables unambiguous recognition of the dense fringes associated with the thick FPI over the free-spectral range determined by the thin FPI. Therefore, the sensor combines the large dynamic range of the thin FPI and the high resolution of the thick FPI. To verify this new concept, a sensor with one 200 µm thick silicon FPI cascaded by another 10 µm thick silicon FPI was fabricated. A temperature range of -50°C to 130°C and a resolution of 6.8×10-3°C were demonstrated using a simple average wavelength tracking demodulation. Compared to a sensor with only the thick silicon FPI, the dynamic range of the hybrid sensor was more than 10 times larger. Compared to a sensor with only the thin silicon FPI, the resolution of the hybrid sensor was more than 18 times higher.

Quantification of optical turbulence in the ocean and its effects on beam propagation.

The influence of optically active turbulence on the propagation of laser beams is investigated in clear ocean water over a path length of 8.75 m. The measurement apparatus is described and the effects of optical turbulence on the laser beam are presented. The index of refraction structure constant is extracted from the beam deflection and the results are compared to independently made measures of the turbulence strength (Cn2) by a vertical microstructure profiler. Here we present values of Cn2 taken from aboard the R/V Walton Smith during the Bahamas optical turbulence exercise (BOTEX) in the Tongue of the Ocean between June 30 and July 12, 2011, spanning a range from 10-14 to 10-10 m-2/3. To the best of our knowledge, this is the first time such measurements are reported for the ocean.

Experimental study of a compressive line sensing imaging system in a turbulent environment.

Turbulence poses challenges in many atmospheric and underwater surveillance applications. The compressive line sensing (CLS) active imaging scheme has been demonstrated in simulations and test tank experiments to be effective in scattering media such as turbid coastal water, fog, and mist. The CLS sensing model adopts the distributed compressive sensing theoretical framework that exploits both intrasignal sparsity and the highly correlated nature of adjacent areas in a natural scene. During sensing operation, the laser illuminates the spatial light modulator digital micromirror device to generate a series of one-dimensional binary sensing patterns from a codebook to encode the current target line segment. A single element detector photomultiplier tube acquires target reflections as the encoder output. The target can then be recovered using the encoder output and a predicted on-target codebook that reflects the environmental interference of original codebook entries. In this work, we investigated the effectiveness of the CLS imaging system in a turbulent environment. The development of a compact CLS prototype will be discussed, as will a series of experiments using various turbulence intensities at the Naval Research Lab's Simulated Turbulence and Turbidity Environment. The experimental results showed that the time-averaged measurements improved both the signal-to-noise radio and the resolution of the reconstructed image in the extreme turbulence environment. The contributing factors for this intriguing and promising result will be discussed.

High-resolution and fast-response fiber-optic temperature sensor using silicon Fabry-Pérot cavity.

We report a fiber-optic sensor based on a silicon Fabry-Pérot cavity, fabricated by attaching a silicon pillar on the tip of a single-mode fiber, for high-resolution and high-speed temperature measurement. The large thermo-optic coefficient and thermal expansion coefficient of the silicon material give rise to an experimental sensitivity of 84.6 pm/°C. The excellent transparency and large refractive index of silicon over the infrared wavelength range result in a visibility of 33 dB for the reflection spectrum. A novel average wavelength tracking method has been proposed and demonstrated for sensor demodulation with improved signal-to-noise ratio, which leads to a temperature resolution of 6 × 10⁻4 °C. Due to the high thermal diffusivity of silicon, a response time as short as 0.51 ms for a sensor with an 80-µm-diameter and 200-µm-long silicon pillar has been experimentally achieved, suggesting a maximum frequency of ~2 kHz can be reached, to address the needs for highly dynamic environmental variations such as those found in the ocean.

Fast-response fiber-optic anemometer with temperature self-compensation.

We report a novel fiber-optic anemometer with self-temperature compensation capability based on a Fabry-Pérot interferometer (FPI) formed by a thin silicon film attached to the end face of a single-mode fiber. Guided in the fiber are a visible laser beam from a 635 nm diode laser used to heat the FPI and a white-light in the infrared wavelength range as the signal light to interrogate the optical length of the FPI. Cooling effects on the heated sensor head by wind is converted to a wavelength blueshift of the reflection spectral fringes of the FPI. Self-temperature-compensated measurement of wind speed is achieved by recording the difference in fringe wavelengths when the heating laser is turned on and then off. Large thermal-optic coefficient and thermal expansion coefficient of silicon render a high sensitivity that can also be easily tuned by altering the heating laser power. Furthermore, the large thermal diffusivity and the small mass of the thin silicon film endow a fast sensor response.

Effectiveness and safety of tranexamic acid for total knee arthroplasty: a prospective randomized controlled trial.

BACKGROUND: Total knee arthroplasty (TKA) is associated with significant perioperative blood loss and need for transfusion. This study aimed to evaluate the effectiveness and safety of tranexamic acid (TXA) to reduce perioperative blood loss in patients receiving TKA. MATERIAL AND METHODS: A total of 92 patients who accepted unilateral TKA from May 2012 to May 2013 randomly received either 15 mg/kg TXA in 100 mL normal saline solution (TXA group, n=46) or the same amount of normal saline solution (placebo group, n=46) at 15 min before the tourniquet was loosened. The following data were recorded: intraoperative blood loss; post-operative drainage at 12 h; total drainage amount; hidden blood loss; total blood loss; transfusion volumes; number of transfusions; post-operative hemoglobin at 1, 3, and 5 days; D-dimer; number of lower limb ecchymoses; and deep vein thrombosis (DVT). RESULTS: A total of 81 patients were available for analysis (TXA group, n=41; placebo group, n=40). Post-operative12-h drainage, post-operative 24-h D-dimer values, total drainage volume, hidden blood loss, total blood loss, and the rate of postoperative ecchymosis were lower in the TXA group than in the placebo group (p<0.05). The post-operative 3-day Hgb was higher in the TXA group than in the placebo group (p=0.000). The rate of transfusion and DVT was similar in both groups (n.s.). CONCLUSIONS: Perioperative blood loss could be reduced after TKA by intravenously injecting 15 mg/kg TXA at 15 min before the tourniquet was loosened. The application of TXA is not associated with increased risk of DVT.

Targeting Hydrogel for Intelligent Recognition and Spatiotemporal Control in Cell-Based Therapeutics.

Smart drug platforms based on spatiotemporally controlled release and integration of tumor imaging are expected to overcome the inefficiency and uncertainty of traditional theranostic modes. In this study, a composite consisting of a thermosensitive hydrogel (polyvinyl alcohol-carboxylic acid hydrogel (PCF)) and a multifunctional nanoparticle (Fe3O4@Au/Mn(Zn)-4-carboxyphenyl porphyrin/polydopamine (FAMxP)) is developed to combine tumor immunogenic cell death (ICD)/immune checkpoint blockade (ICB) therapy under the guidance of magnetic resonance imaging (MRI) and fluorescence imaging (FI). It can not only further recognize the target cells through the folate receptor of tumor cells, but also produce thermal dissolution after exposure to near-infrared light to slowly release FAMxP in situ, thereby prolonging the treatment time and avoiding tumor recurrence. As FAMxP entered the tumor cells, it released FAMx in a pH-dependent manner. Chemodynamic, photothermal and photodynamic therapy can cause significant ICD in cancer cells. ICB can thus be further enhanced by injecting anti-programmed cell death ligand 1, improving the effectiveness of tumor treatment. The developed PCF-FAMxP composite hydrogel may represent an updated drug design approach with simple compositions for cooperative MRI/FI-guided targeted therapeutic pathways for tumors.

Impacts of underwater turbulence on acoustical and optical signals and their linkage.

Acoustical and optical signal transmission underwater is of vital interest for both civilian and military applications. The range and signal to noise during the transmission, as a function of system and water optical properties, in terms of absorption and scattering, determines the effectiveness of deployed electro-optical (EO) technology. The impacts from turbulence have been demonstrated to affect system performance comparable to those from particles by recent studies. This paper examines the impacts from underwater turbulence on both acoustic scattering and EO imaging degradation, and establishes a framework that can be used to correlate these. It is hypothesized here that underwater turbulence would influence the acoustic scattering cross section and the optical turbulence intensity coefficient in a similar manner. Data from a recent field campaign, Skaneateles Optical Turbulence Exercise (SOTEX, July, 2010) is used to examine the above relationship. Results presented here show strong correlation between the acoustic scattering cross-sections and the intensity coefficient related to the modulation transfer function of an EO imaging system. This significant finding will pave ways to utilize long range acoustical returns to predict EO system performance.

Determination of flow orientation of an optically active turbulent field by means of a single beam.

The cross-flow orientation of an optically active turbulent field was determined by Fourier transforming the wander of a laser beam propagating in the ocean. A simple physical model for the measured effect is offered, and numerical simulations are performed. The simulations are in good agreement with measurements, validating the assumptions made in the model.

Three-dimensional ordered DNA network constructed by a biomarker pair for accurate monitoring of colorectal cancer.

Precise and early screening of colorectal cancer (CRC) is one crucial yet challenging task for its treatment, and the analysis of multi-targets of CRC in a single assay with high accuracy is essential for pathological research and clinical diagnosis. Here, a CRC-related biomarker pair, microRNA-211 (miRNA-211) and H2S, was detected by constructing a three-dimensional (3D) ordered DNA network. First, trace amount of miRNA-211 could initiate a hybridization chain reaction-based amplification process. A highly ordered 3D DNA network was formed based on the organized assembly of DNA-cube frameworks that were constructed by DNA origamis and Ag nanoparticles (NPs) encapsulated inside. In the presence of the H2S, Ag NPs within the network can be etched to generate Ag2S quantum dots, which could be better visualized in fluorescence in situ cell imaging. Using the 3D DNA ordered network as the sensing platform, it can acquire dual analysis of biomolecule (miRNA-211) and inorganic gas (H2S) in vitro, overcoming the limitations of single type of biomarker detection in a single assay. This assay achieved a wide linearity range of H2S from 0.05 to 10 µM, and exhibited a low limit of detection of 4.78 nM. This strategy allows us to acquire the spatial distributions of H2S and miRNA expression levels in living CRC cells simultaneously, providing a highly sensitive and selective tool for early screening and monitoring of CRC.

Photocatalytic degradation of bisphenol A by temperature-sensitive magnetic hydrogel with enhanced service life.

Easy diffusion and low reusability limit the practicality of photocatalysts. In this study, a hollow sphere (HS) heterojunction was synthesized based on oxygen-doped carbon nitride (OCN) and layered double hydroxides (LDHs). A thermosensitive HS hydrogel (HS Gel) was prepared by mixing HS with N-isopropylacrylamide. Bisphenol A (BPA), being widely manufactured and used in commercial and domestical products and its high toxicity, was chosen as the target pollutant to demonstrate the photocatalytic ability and practicality of the HS Gel. HS Gel presented effective BPA degradation (95% degradation in 70 mins, 4.2 × 10-2 min-1 of kobs) at ambient temperature which is much better than kobs = 1.8 × 10-2 min-1 of OCN and kobs = 0.08 × 10-2 min-1 of LDH), and increased by two-fold the recycling service life (retention of >80% degradation efficiency after 13 usage cycles) compared to other carbon-based photocatalysts (retention of >80% degradation efficiency after 5-6 usage cycles). This is due to its multifunctional characteristics (magnetic property and thermal sensitivity). Under ambient temperature, the hydrophilic HS Gel swelled in the aqueous solution, which promoted the photocatalytic reaction between HS and BPA in the gel state. After the reaction, the HS Gel was subjected to shrinkage by high temperature heating to enhance the mechanical strength for recovery. The magnetic recovery was realized by the paramagnetic properties of layered double oxide to reduce environmental interference. Detailed studies of HS gel related to enhanced service life were conducted including structural changes, catalyst leaking and magnetic changing. A new kind of type Ӏ plus Z-scheme mechanism was also proposed based on the Kubelka-Munk equation, UV diffuse reflectance spectroscopy and Mott-Schotty technique.