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In this paper, we present a distal-scanning common path probe for optical coherence tomography (OCT) equipped with a hollow ultrasonic motor and a simple and specially designed beam-splitter. This novel probe proves to be able to effectively circumvent polarization and dispersion mismatch caused by fiber motion and is more robust to a variety of interfering factors during the imaging process, experimentally compared to a conventional noncommon path probe. Furthermore, our design counteracts the attenuation of backscattering with depth and the fall-off of the signal, resulting in a more balanced signal range and greater imaging depth. Spectral-domain OCT imaging of phantom and biological tissue is also demonstrated with a sensitivity of ∼ 1 0 0 dB and a lateral resolution of ∼ 3 μ m. This low-cost probe offers simplified system configuration and excellent robustness, and is therefore particularly suitable for clinical diagnosis as one-off medical apparatus. [ABSTRACT FROM AUTHOR]

Background: Pharyngocutaneous fistula (PCF) is one of the most common complications of total laryngectomy. This study is to investigate the efficacy of a novel platform called transnasal negative pressure therapy (TNPT) in the management of PCF. Methods: We retrospectively reviewed 47 patients who underwent total laryngectomy between April 2015 and February 2021 and developed PCF in our hospital. We focused on the healing rate, dressing change frequency, and healing time between the TNPT and non‐TNPT groups. The 2 years overall survival (OS) was compared through the log‐rank test. Results: There were 18 patients in the TNPT group and 29 in the non‐TNPT group. There was no significant between‐group difference in the healing rate (chi‐square test). However, the frequency of dressing changes was significantly lower (p < 0.001) and the healing time was significantly shorter (p = 0.0194) in the TNPT group than in the non‐TNPT group. The 2‐year OS rate was significantly higher in the TNPT group (p = 0.0473, log‐rank test). Conclusion: TNPT promoted wound healing after surgery for PCF and improved the 2‐year OS rate. This tool is worthy of clinical application and promotion. [ABSTRACT FROM AUTHOR]

Barley leaf stripe, caused by Pyrenophora graminea, is an essential systemic seed-borne disease in barley worldwide. Barley is a major cereal crop in the Qinghai–Tibet Plateau, and barley production has been threatened by leaf stripe in this region, particularly in organic farming regions. Detecting the pathogen in infected barley seeds is crucial for managing barley leaf stripe. In this study, a loop-mediated isothermal amplification (LAMP) assay was developed to detect the pathogen based on primers designed based on the sequence of the pig 14 gene (GenBank: AJ277800) of P. graminea. The optimal concentrations of MgSO4, dNTPs, and enzymes in the LAMP reaction system were established as 10.0 mM, 1.0 mM, and 8 U in a 25 μL reaction volume, respectively. The established LAMP methods for detecting P. graminea were optimally performed at 63 °C for 70 min with high reliability. The minimum detection limit was 1 × 10−2 ng·μL−1 in the 25 μL reaction system. The specificity of LAMP for P. graminea was validated with eight fungal species. All DNA extracts from P. graminea-infected barley seeds with incubation, intact, and smashed treatments were applied in LAMP and confirmed to enable the detection of the pathogen. The LAMP assay in this study could facilitate the detection of P. graminea in barley seeds onsite, provide information for seed health certificates, and help decide on seed treatment in leaf stripe management. [ABSTRACT FROM AUTHOR]

[Objective] To provide a reference for detection of barley seeds and effective prevention and control of barley stripe, this study established a detection system for barley stripe based on loop-mediated isothermal amplification (LAMP) technology. [Method] In this study, five sets of specific primers were de-signed based on the ITS-rDNA sequences of P. graminea, and one set was screened to optimize reaction temperature based on six gradients (60, 61, 62, 63, 64 and 65 °C). Then, the LAMP system for efficient detection of the pathogen was established. Its specificity was tested based on LAMP amplification of DNA of genes from P. graminea, Ustilago hordei, Ustilago nuda, Dactylobotrys graminicola, Alternaria alternata and Fusarium graminearum. The sensitivity was analyzed by testing genes at levels of 310, 31, 3. 1, 0.31, 0.031 and 0.003 1 pg/µL. At last, it was used for testing and verifying seeds of five barley varieties. [Result] The established LAMP methods for detecting P. graminea performed optimally at 63 °C for 70 min with specific primers of set 2. Under the optimal reaction conditions, this method had good specificity for P. graminea with minimum detection limit of 0.31 pg/µL. The P. graminea-carrying rates of Dulihuang, Chaiqing 1, 1141, Beiqing 9 and Kunlun 15 seeds were 68.18%, 72.73%, 100%, 77.27% and 68.18%, respectively. [Conclusion] The established LAMP method can be used to detect the P. graminea in barley seeds within 70 min at 63 µC. [ABSTRACT FROM AUTHOR]

Swept laser based on the acousto-optic deflector (AOD) is a promising swept source in optical coherence tomography (OCT) applications for its high wavenumber linear sweep without mechanical motion. However, the poor coherence length and the elongated cavity of the laser imposed limitations on the acquisition of high-quality images with adequate imaging depth and high imaging speed. In this Letter, we demonstrate a compact high-speed wavenumber linear swept laser based on AOD using Doppler shift compensation, achieving a high linearity of Pearson's R of 0.999991, a duty cycle of ∼100%, an extended coherence length of 5.7 mm, an output power of 18 mW, and excellent phase stability at a sweep speed of 500 kHz. OCT structural images with a system sensitivity of 103.2 dB and OCT angiography (OCTA) of human palm in vivo have been successfully performed, serving as a compelling demonstration of the excellent performance of this swept laser. We believe that the proposed laser will be of high potential in various clinical and industrial applications in the future.

Stretched-pulse mode-locked (SPML) lasing based on a chirped fiber Bragg grating (CFBG) has proven to be a powerful method to generate wavelength-swept lasers at speeds of tens of megahertz. However, light transmitted through the CFBG may lead to undesirable laser oscillation that disrupts the mechanism of the laser active mode locking in the theta ring cavity. In this Letter, we demonstrate a simple and low-cost approach to suppress the transmitted light and achieve an effective duty cycle of ∼100% with only one CFBG and no need for intra-cavity semiconductor optical amplifier (SOA) modulation, extra-cavity optical buffering, and post amplification. By utilizing polarization isolation of the bi-directional CFBG, a swept laser centered at 1305 nm, with repetition rate of 10.3 MHz, optical power of 84 mW, and 3 dB bandwidth of 109 nm, is demonstrated. Ultrahigh speed 3D optical coherence tomography (OCT) structural imaging of a human palm in vivo using this swept laser is also demonstrated. We believe that this ultrahigh speed swept laser will greatly promote the OCT technique for industrial and biomedical applications.