Distributed shape detection for an acoustic sensitive optical cable with DAS.

Acoustic sensitive optical cables (ASOCs) and their shape detection are vital in underwater acoustic monitoring, and a distributed ASOC shape detection method is demonstrated with distributed acoustic sensing (DAS) technology. The accurate three-dimensional (3D) position of each ASOC unit is obtained from DAS signals and the prior position information of auxiliary acoustic sources by using a proposed adaptive peak allocation algorithm. Preliminary work has demonstrated single-point 3D localization and distributed ASOC shape detection, and the error is 6.53 cm. To the best of our knowledge, it is the first time that distributed ASOC shape detection is achieved with DAS. This method will promote the development of ASOC applications, such as underwater target detection and towed array correction.

Voiceprint and position information detection of non-cooperative ship with Φ-OTDR and suspended sensitized optical cable.

Target detection is significant in many fields, including oceanic security, marine ecology, etc. In this paper, phase sensitive optical time domain reflectometry (Φ-OTDR) is introduced for the non-cooperative ship detection, with large-scale diversity technology and suspended sensitized optical cable. In outfield experiments, the ship's voiceprint information is obtained in high fidelity, the ship's power spectrum is analyzed, and the over-top detection is achieved. Moreover, an array orientation method based on adaptive phase difference correction (APDC) is proposed to track the ship, suppressing the delay jitter influence of acoustic transmission underwater. This is the first time that voiceprint information of the non-cooperative ship is high-fidelity acquired and deeply analyzed with Φ-OTDR and suspended sensitized optical cable, which is conducive to the detection and identification of marine targets, and proves the potential of Φ-OTDR in hydroacoustic detection applications.

Distributed fiber mountain seismic monitoring and steady-state analysis under natural earthquakes.

Mountain dynamic response monitoring plays important roles in geological disaster evolution monitoring and warning. A distributed mountain seismic monitoring and steady-state analysis method is demonstrated with distributed acoustic sensing (DAS) and a natural earthquake stimulus. In the field test, the seismic detection capability is first verified by comparing the recorded seismic waveforms from DAS and existing seismic stations. The vibration signal difference between steady-state and unsteady-state mountain parts is apparent; the operational modal analysis method is utilized to extract the response difference and to monitor the disaster evolution process. The proposed method has many advantages, including being easy to deploy, all-weather online monitoring, etc. It is believed that the proposed method will broaden the DAS application scope and promote the development of geological disaster early warning such as landslides and collapses.

Controlling Charge Transport in Molecular Wires through Transannular π-π Interaction.

This paper describes the influence of the transannular π-π interaction in controlling the carrier transport in molecular wires by employing the STM break junction technique. Five pentaphenylene-based molecular wires that contained [2.2]paracyclophane-1,9-dienes (PCD) as the building block were prepared as model compounds. Functional substituents with different electronic properties, ranging from strong acceptors to strong donors, were attached to the top parallel aromatic ring and used as a gate. It was found that the carrier transport features of these molecular wires, such as single-molecule conductance and a charge-tunneling barrier, can be systematically controlled through the transannular π-π interaction.

High SNR Φ-OTDR with Multi-Transverse Modes Heterodyne Matched-Filtering Technology.

Phase-sensitive optical time domain reflectometer (Φ-OTDR) has attracted attention in scientific research and industry because of its distributed dynamic linear response to external disturbances. However, the signal-to-noise ratio (SNR) of Φ-OTDR is still a limited factor by the weak Rayleigh Backscattering coefficient. Here, the multi-transverse modes heterodyne matched-filtering technology is proposed to improve the system SNR. The capture efficiency and nonlinear threshold are increased with multiple transverse modes in few-mode fibers; the incident light energy is permitted to be enlarged by a wider probe pulse by using heterodyne matched-filtering without spatial resolution being deteriorated. As far as we know, this is the first time that both multi-transverse modes integration method and digital heterodyne matched filtering method have been used to improve the SNR of Φ-OTDR simultaneously. Experimental results show that the noise floor is reduced by 11.4 dB, while the target signal is kept. We believe that this proposed method will help DAS find important applications in marine acoustic detection and seismic detection.

All-fiber narrow-bandwidth rectangular Optical filter with reconfigurable bandwidth and tunable center wavelength.

In this manuscript, a novel narrow-bandwidth rectangular optical filter based on multi-phase-shifted fiber Bragg grating (MPSFBG) is proposed. Using the local temperature control technology, the precise controllable phase shifts are introduced at different positions of the fiber Bragg grating (FBG). Therefore, the bandwidth of the MPSFBG-based filter with good shape factor can be reconfigured from 70 MHz to 1050 MHz by flexibly controlling the numbers and the positions of the phase shifts introduced in the MPSFBG. In addition, the center wavelength of the MPSFBG-based filter can be tuned through controlling the MPSFBG's environment temperature, and the tuning range of 22 GHz is realized. This is one of the best results for the narrow-bandwidth rectangular optical tunable filter with reconfigurable bandwidth. It can be widely used in the processing of reconfigurable signals in the optical communication networks and microwave photonics.

Distributed optical fiber hydrophone based on Φ-OTDR and its field test.

In this letter, a distributed optical fiber hydrophone (DOFH) based on Φ-OTDR is demonstrated and tested in the field. The specially designed sensitized optical cable with sensitivity up to -146 dB rad/µPa/m is introduced, and an array signal processing model for DOFH is constructed to analyze the equivalence and specificity of the distributed array of acoustic sensors. In the field test, a 104-meter-long optical cable and a Φ-OTDR system based on heterodyne coherent detection (Het Φ-OTDR) is utilized, and underwater acoustic signal spatial spectrum estimation, beamforming and motion trajectory tracking with high accuracy can be realized. As far as we know, this is the first report on the field trial of DOFH based on Φ-OTDR. The DOFH has the potential to achieve an array range of tens of kilometers, with elements spaced up to the meter level and flexible configuration, which has a broad application prospect for marine acoustic detection.

Analysis of Endoscopy Findings to Identify Early Gastric Cancers with Tumor Budding: A Retrospective Study.

BACKGROUND: No reliable method has been reported for determining tumor budding with frozen sections during surgical procedures. This study investigated endoscopic features predictive of tumor budding in early gastric cancers (EGC). METHODS: This retrospective study evaluated data from 137 patients diagnosed with EGC who underwent endoscopy, followed by endoscopic submucosal dissection (ESD); 71 patients underwent a second gastrectomy. Based on pathological analyses, lesions were categorized as being positive (n = 80) or negative for tumor budding (n = 57). Endoscopic features were analyzed using multivariable logistic regression. Patient survival rates were analyzed with Kaplan-Meier method and log-rank test. RESULTS: Mean age of our study population was 66 years (range, 31-86 years). The tumor budding-positive cohort (73.3 ± 5.9 years) was significantly older than the tumor budding-negative cohort (56.7 ± 7.6 years) (p < 0.001). Endoscopic features significantly different between tumor budding-positive and budding-negative groups included tumor size (p = 0.003), remarkable redness (p = 0.015), and margin elevation (p < 0.001). Tumor size (odds ratio (OR): 1.561; 95% confidence interval (CI): 0.984, 2.285; p = 0.047) and margin elevation (OR: 2.141; 95% CI: 1.147, 5.117; p = 0.003) were independent predictors of tumor budding. Margin elevation was found in 19.3% of tumor budding-negative and 53.8% of budding-positive cases. In the tumor budding-positive group, ESD and second gastrectomy were associated with disease-free survival. CONCLUSIONS: Margin elevation and large tumor size (> 29 mm) of EGCs on endoscopy are promising imaging biomarkers for predicting tumor budding in EGCs. ESD and a second gastrectomy can be better for tumor budding-positive patients with EGCs.

Recent Progress in Distributed Fiber Acoustic Sensing with Φ-OTDR.

Distributed fiber acoustic sensing (DAS) technology can continuously spatially detect disturbances along the sensing fiber over long distance in real time. It has many unique advantages, including, large coverage, high time-and-space resolution, convenient implementation, strong environment adaptability, etc. Nowadays, DAS becomes a versatile technology in many fields, such as, intrusion detection, railway transportation, seismology, structure health monitoring, etc. In this paper, the sensing principle and some common performance indexes are introduced, and a brief overview of recent DAS researches in Shanghai Institute of Optics and Fine Mechanics (SIOM) is presented. Some representative research advances are explained, including, quantitative demodulation, interference fading suppression, frequency response boost, high spatial resolution, and distributed multi-dimension localization. The engineering applications of DAS, carried out by SIOM and other groups, are summarized and reviewed. Finally, possible future directions are discussed and concluded. It is believed that, DAS has great development potential and application prospect.

Narrow linewidth swept laser source based on cascaded multi-wavelength injection of DFB lasers.

A linearly swept laser source over broadband with a fast sweep rate and narrow linewidth is realized using a novel optoelectronic scheme based on a multi-wavelengths (mutually coherent) injected distributed feedback (DFB) laser. Under the condition of multi-wavelengths injection, the injection-locking and four-wave mixing (FWM) process can occur simultaneously in the DFB laser, inducing a swept laser source with a sweep range of 100 GHz and sweep rate of 10 THz/s. Furthermore, with the phase noise character analyzation of the swept laser source, the phase noise deterioration due to the radio frequency (RF) signal is studied quantitatively. Besides the influence of the RF signal noise, the phase noise deterioration in the FWM process can be suppressed completely with the phase-locked pump beam and signal beam based on the injection-locking principle. This low phase noise swept laser source with sub-kilohertz linewidth could have wide applications in lidar.

Multi-source aliasing suppression for distributed fiber acoustic sensing with directionally coherent enhancement technology.

Distributed fiber acoustic sensing (DAS) can detect almost all disturbances along the sensing fiber and is widely applied. However, the signals from multiple adjacent disturbance sources are superimposed, according to the sensing principle. A directionally coherent enhancement technology is demonstrated for DAS to suppress multi-source aliasing in air. In preliminary works, two situations are considered for feasibility verification. The submerged weak target signal is effectively extracted from strong broadband noise, and two different same-frequency signals from two sources are separately rebuilt with the same detected signal. As far as we know, this is the first time that the directionally coherent enhancement is proposed for DAS and the multi-source aliasing is suppressed. This technique will help DAS find new important foreground in acoustic detection of large-scale plants with many similar noisy devices, including discharge detection in high voltage substations and acoustic emission flaw detection in mechanical factories.

Practical multi-class event classification approach for distributed vibration sensing using deep dual path network.

Influenced by severe ambient noises and nonstationary disturbance signals, multi-class event classification is an enormous challenge in several long-haul application fields of distributed vibration sensing technology (DVS), including perimeter security, railway safety monitoring, pipeline surveillance, etc. In this paper, a deep dual path network is introduced into solving this problem with high learning capacity. The spatial time-frequency spectrum datasets are built by utilizing the multidimensional information of DVS signal, especially the spatial domain information. With the novel datasets and a high-parameter-efficiency network, the proposed scheme presents good reliability and robustness. The feasibility is verified in an actual railway safety monitoring field test, as a proof-of-concept. Seven types of real-life disturbances were implemented and their f1-scores all reached up to 97% in the test. The performance of this proposed approach is fully evaluated and discussed. The presented approach can be employed to improve the performance of DVS in actual applications.

The mechanism and tumor inhibitory study of Lagopsis supine ethanol extract on colorectal cancer in nude mice.

BACKGROUND: This study was aimed to determination the tumor inhibitory effect and explore the potential mechanisms of Lagopsis supine ethanol extract (Ls) on colorectal cancer. METHODS: The cell growth inhibition experiment of Ls in colorectal cancer cell lines was determined by MTT method in the time course of 24, 48 and 72 h in four gradient drug concentrations. The protein expression levels of pSTAT3, pJAK2, STAT3, JAK2, Bcl-2 and caspase 3 were measured by Western blot method. The mRNA levels of the downstream genes of STAT3 were detected through semi-quantitative RT PCR. Sixty Balb/c-nude mice were xenograft with HCT116 colorectal cancer cells through subcutaneously. The xenografts were divided into five groups: model group, positive group (capecitabine 300 mg/kg) and three dosages of Ls treated groups (75, 150 and 300 mg/kg). Tumor size and tumor weight were calculated for evaluation the anti-tumor effects. H & E staining and immunohistochemical analysis were used to determine the histopathological changes and the levels of pSTAT3 and pJAK2 in the tumor tissues. RESULTS: Ls exhibited a significant anti-proliferation effect in HCT116 and SW480 cells in vitro. The protein levels of pSTAT3, pJAK2 and Bcl-2, and the mRNA levels of Bcl-2 and Bak notably reduced with a dose-dependent manner. While the protein levels of caspase 3, and mRNA levels of Bax and caspase-3 remarkably increased in the gradient dosage of Ls in HCT116 cells. HCT116 in vivo xenografts experiment showed that the growth of the tumors significantly inhibited by Ls administration, which with no any significant body weight changes in each experiment group. The histopathology analysis displayed that Ls significantly reduced the inflammatory cells in tumor tissue. Furthermore, Ls also significantly down-regulate the protein levels of pSTAT3 and pJAK2 in the tumor tissues, compared with the model group. CONCLUSIONS: This work shows that Ls inhibited the cell proliferation of colorectal cancer in vitro and significantly reduced the tumor growth in HCT116 xenografts in vivo, which is probably related with the JAK/STAT signal pathway.

Coinfection with cryptococcus and aspergillus in an immunocompetent adult: A case report.

RATIONALE: Aspergillus and Cryptococcus exposure can cause serious secondary infections in human lungs, especially in immunocompromised patients or in conjunction with a chronic disease caused by low disease resistance. Primary invasive fungal infections are clinically rare; therefore, coexistence of 2 fungi at an infection site is uncommon. This paper reports a case of healthy male who was diagnosed with both Cryptococcus neoformans and Aspergillus infections. PATIENT CONCERNS: A healthy 33-year-old male office worker was admitted to the Second Hospital of Jilin University for hemoptysis. A chest computed tomography (CT) scan showed a cavity, which was formed by the thick dorsal wall of the lower left lobe with an irregular inner wall and burr changes around the lesion. INTERVENTION: After 1.0 week of antibiotic and antituberculosis treatment, the hemoptysis symptoms remained. A resection of the left lower lobe was performed. DIAGNOSES: The postoperative pathological reports indicated the presence of both Aspergillus and Cryptococcus. The 2 fungal lesions were separate but within the same location. OUTCOMES: After treatment, the patient no longer had hemoptysis. LESSONS: The current study indicated that fungi can infect not only immunocompromised patients but also healthy people, and that there can be 2 separate fungal infections at the same infection site.

Brillouin Frequency Shift of Fiber Distributed Sensors Extracted from Noisy Signals by Quadratic Fitting.

It is a basic task in Brillouin distributed fiber sensors to extract the peak frequency of the scattering spectrum, since the peak frequency shift gives information on the fiber temperature and strain changes. Because of high-level noise, quadratic fitting is often used in the data processing. Formulas of the dependence of the minimum detectable Brillouin frequency shift (BFS) on the signal-to-noise ratio (SNR) and frequency step have been presented in publications, but in different expressions. A detailed deduction of new formulas of BFS variance and its average is given in this paper, showing especially their dependences on the data range used in fitting, including its length and its center respective to the real spectral peak. The theoretical analyses are experimentally verified. It is shown that the center of the data range has a direct impact on the accuracy of the extracted BFS. We propose and demonstrate an iterative fitting method to mitigate such effects and improve the accuracy of BFS measurement. The different expressions of BFS variances presented in previous papers are explained and discussed.

High spatial resolution phase-sensitive optical time domain reflectometer with a frequency-swept pulse.

A high spatial resolution phase-sensitive optical time domain reflectometer (ϕ-OTDR) with an optical frequency-swept pulse (FSP) is proposed, and the experimental results are presented in the Letter. The FSP ϕ-OTDR uses optical pulses with linear frequency modulation with higher pulse energy for longer sensing fiber and uses matched filter in the receiver to compress the processed pulse width. Thus, the contradiction between spatial resolution and the working distance in ordinary ϕ-OTDR is relaxed. A spatial resolution of 30 cm, a sensing distance of 19.8 km, and a signal-to-noise ratio of 10 dB for vibration sensing were obtained experimentally. To our best of our knowledge, this is the first time that a sub-meter spatial resolution over such a long sensing range has been reported in ϕ-OTDR sensors.

Dual blocking of PI3K and mTOR signaling by NVP-BEZ235 inhibits proliferation in cervical carcinoma cells and enhances therapeutic response.

NVP-BEZ235 is a novel dual PI3K/mTOR inhibitor that shows dramatic effects on many tumors, but its effects on cervical carcinoma cells are largely unknown. In the present study, we investigated the effects of NVP-BEZ235 on the proliferation and invasion of cervical carcinoma cells in vitro and clarified its mechanism of action. In cellular settings with human cervical carcinoma cell lines, this molecule effectively and specifically blocked dysfunctional PI3K/mTOR pathway activation, suppressed cell growth in a time- and concentration-dependent manner, led to G1 cell cycle arrest, and induced apoptosis. NVP-BEZ235 suppressed HeLa cell invasiveness and metastasis by inhibiting the PI3K/Akt/MMP-2 pathway. We further demonstrated that NVP-BEZ235 treatment in combination with cisplatin or carboplatin induced a synergistic anti-tumoral response in cervical carcinoma cells. These findings suggested that NVP-BEZ235 could regulate growth and invasion of cervical carcinoma cells; thus it may provide a potential therapy for cervical carcinoma.

Ultra-broadband phase-sensitive optical time-domain reflectometry with a temporally sequenced multi-frequency source.

A phase-sensitive optical time-domain reflectometry (Φ-OTDR) with a temporally sequenced multi-frequency (TSMF) source is proposed. This technique can improve the system detection bandwidth without the sensing range decreasing. Up to 0.5 MHz detection bandwidth over 9.6 km is experimentally demonstrated as an example. To the best of our knowledge, this is the first time that such a high detection bandwidth over such a long sensing range is reported in Φ-OTDR-based distributed vibration sensing. The technical issues of TSMF Φ-OTDR are discussed in this Letter. This technique will help Φ-OTDR find new important foreground in long-haul distributed broadband-detection applications, such as structural-health monitoring and partial-discharge online monitoring of high voltage power cables.