Laser remote sensing of seismic waves is extensively utilized in earthquake monitoring and resource exploitation. This article leverages wavefront sensors’ high resolution and array detection capabilities to effectively conduct planar scanning of target areas in seismic wave laser remote sensing research, thereby properly acquiring regional vibration data. The error margin is between 1% and 2% relative to the source information.

Dynamic 3D displacement field measurement is an effective means to characterize the electrical performance stability and structural soundness of microsystems. Combining off-axis lensless Fourier transform multiplexed digital holography and multi-illumination profilometry, a dual-wavelength dual-camera optical setup with a multi-illumination system is developed to simultaneously acquire four phase images with different sensitivity vectors, as well as the object shapes. Meanwhile, the shared reference wave in off-axis lensless Fourier holography gives a convenient way for sensitivity vector modification and phase image registration, which are based on the stereo checkerboard calibration method. The dynamic 3D displacement fields and the strain maps of an energized integrated circuit board reveal that the inhomogeneous thermal expansion may cause some damage to chips, such as pin desoldering and microstructure fracture.

Digital holography has been frequently used to measure the micro-deformation in mechanical tests due to its full-field measurement with high resolution and accuracy. To measure dynamic three-dimensional absolute displacements without a known reference displacement, a new technique based on the combination of off-axis multiplexed digital holography and stereo photogrammetry is proposed. Under the illumination of two different wavelength lasers along various directions, two off-axis multiplexed holograms recorded by the dual-camera system are used to extract four phase maps with different sensitivity vectors simultaneously. Meanwhile, the variation of sensitivity vectors and registration of phase maps are carried out by the object shape measured by the dual-camera system. By the four registered phases with four varying sensitivity vectors, three-dimensional absolute displacements can be determined. The feasibility of our method is well demonstrated by a quantitative experiment and finite element analysis, and the dynamic measurement of a resistor undergoing thermal expansion is presented.

This paper develops a real-time dual-channel speckle interferometry system based on an improved dual-observation configuration to address the issue of simultaneous measurement of the out-of-plane displacement and slope. A dual-observation configuration combined with an additional light path is used to provide the possibility to create two measurement channels corresponding to the out-of-plane displacement and slope, respectively. In the system, two symmetric observation light paths are slightly displaced from each other by a deliberate tilt of the plane mirror to introduce an adjustable lateral shear. One of the two observation beams is shared by both measurement channels to improve the system's stability. Besides, using the spatial carrier phase-shifting technique induced by multi-aperture, the real-time phase retrieval is achieved for simultaneous measurement of the dynamic out-of-plane displacement and slope. Both the experimental investigation and the non-destructive testing (NDT) application are finally presented to demonstrate the feasibility and effectiveness of the proposed system.

A hybrid nondestructive testing (NDT) approach based on the fusion of shearography and digital speckle pattern interferometry (DSPI) is proposed for depth characterization of internal defect. To this end, a novel dual-sensitive speckle interferometry system is developed for both shearography and DSPI measurements. On one hand, shearography imaging results are used to identify the internal defect location, shape, and boundary qualitatively for the preparation of subsequent depth characterization. On the other hand, an improved mechanical model combined with bending theory and DSPI imaging results is built to perform the internal defect depth prediction. Finally, the hybrid NDT experiment for a thin metallic plate with an internal planar defect is conducted for feasibility validation of the proposed fusion method. The results indicate that the relative error of defect depth detection is less than 5% compared to the existing method and show that the proposed fusion method can successfully perform improved depth characterization of internal defect.

Due to limits in the properties of digital cameras, in-line digital holography is commonly used to take full advantage of the sampling space of the camera. To realize the dynamic high-resolution measurement of in-line digital holography, dual-camera dynamic in-line digital holography is proposed. By means of a two-step phase-shifting cepstrum algorithm and a dual-camera parallel phase-shifting recording optical path, the complex amplitude of the object wave can be reconstructed without its zero-order and conjugate terms. Meanwhile, a novel spherical wave interference calibration method is also developed for the dual-camera recording system, and image correction is carried out via rotation, translation, and diffraction, with an average error of phase correction of 0.1107 rad. Finally, the feasibility and effectiveness of the proposed technique is well demonstrated by a practical application of dynamic temperature field measurement in a transparent medium.

A method based on the measurement of out-of-plane displacement by the phase-shifting digital speckle pattern interferometry is proposed to detect the edge of internal defects. The out-of-plane displacement is scanned by the scanning method of gradient streamlines first, which can provide paths through the defect edge with the best signal-to-noise ratio everywhere. Then, continuous wavelet transform (CWT) combined with the weighted structural intensity of the wavelet maxima is applied to detect the hidden singularities of the gradient streamlines that form the defect edge later. Moreover, the weighted structural intensity method is optimized to adapt to the detection of the hidden singularity by CWT. The results of theory, simulation, and experiments agree well, and the proposed method is efficient in internal defect detection. (C) 2019 Society of Photo-Optical Instrumentation Engineers (SPIE)

In this paper, a new method, Moment-Stiffness Method (MSM), is proposed for measuring the edge and depth of internal defects which can be applied to any structures with known stiffness. MSM is based on the relation of the differences of displacements between flawed and flawless areas caused by the change of stiffness. Theoretical, numerical and experimental results are presented. In the method, digital speckle pattern interferometry (DSPI) is used to measure the out-of-plane displacement of a plate with an internal defect. In the detection of the first specimen, the distributions of first- and second-order radial derivatives of the out-of-plane displacement are obtained by the radial numerical differential. Then the full edge and depth of the defect is accurately determined using MSM. All the results indicate that the proposed method is an effective tool to measure internal defects precisely.

In this paper, a new detection method for two identical frequency vibrations along optic fiber is proposed, by discrimination of their phase relationship in polarization optical time-domain reflectometer (POTDR). A vibration on fiber would modulate its index and birefringence, then it can consequently change the state of polarization (SOP) of the scattering signal. However, multiple simultaneous vibrations at different positions would result in random fluctuating SOP of the scattering signal, which make them very difficult to be identified. In our proposed method, the phase of the vibration signal along the fiber is obtained by Fast Fourier Transform. Therefore, two vibration events with the same frequency could be distinguished effectively by using the pattern of the phase distribution. The principle of the method is analyzed in detail. Both simulation and experiment results are presented to demonstrate the validity and limitation of this method. It could be widely used for safety monitoring of long distance perimeters, electrical transmission line, and so on.

The wave-plate model is frequently used to analyze the signal of polarization time domain reflectometry (POTDR). However, since the wave-plate model is initially developed to simulate the polarization property of optical fiber communication links, it does not describe the signal of POTDR very well. In this paper, we adapt the wave-plate model for the simulation of POTDR. According to the comparison with experiment, it shows that the adopted model is more suitable than the original model to analyze the POTDR signal.

In this letter, we present a novel and simple method to suppress the signal fading phenomena in polarization optical time-domain reflectometry (POTDR). A combination of polarization multiplexing and multi-directional polarization analyzing is utilized to achieve the goal. A short polarization maintaining fiber is connected to a multi-wavelength laser source to generate polarization multiplexing probe lightwaves. The signals for different probe lightwaves are demultiplexed by a dense wavelength division multiplexer. Then, the three polarizers with different orientations are used to analyze the signals, respectively. The principle of the method is analyzed in detail. Experiments demonstrate the validity of the system to suppress the signal fading. The proposed method can eliminate the location error of event caused by the signal fading and the signal-to-noise ratio is also improved compared with a traditional POTDR.

It's very important to detect the leakage of oil pipeline timely and accurately in order to reduce the losses and ensure the smooth operation of oil pipeline. However, the leakage monitoring of the pipeline is difficult because normally the pipeline is very long and is often buried underground or underwater. Brillouin optical time domain reflectometry (BOTDR), which can distributedly measure the temperature of fiber, has good potential in monitoring the leakage of oil pipeline. In this paper, the feasibility of monitoring the leakage of oil pipeline by using BOTDR is investigated with both laboratory experiments and field tests. The principle of the BOTDR is given at first. Then laboratory experiments are carried out to demonstrate the effectiveness of BOTDR in the leakage monitoring. Several sensing cables with different structures are evaluated in the experiments by comparing their effectiveness in the leakage monitoring and four kinds of laying styles of the sensing cables are compared as well. After that, field tests are carried out by simulating the leakage of oil pipeline. The monitoring effects for different leakage amounts are tested with BOTDR. The sensing cable suitable to monitor the leakage of oil pipeline is chosen by considering both the effect of leakage monitoring and the economics. A few laying styles are compared by testing the sensitivity of detecting the leakage of pipeline. Testing results show that the laying style of straight line along the pipeline can detect the leakage of 1.1m 3 /h. A much more sensitive laying style by wrapping up the sensing cable and pipeline with plastic film can detect the leakage of 0.1m 3 /h.

A polarization optical time-domain reflectometer (POTDR) can distributedly measure the vibration of fiber by detecting the vibration induced polarization variation only with a polarization analyzer. It has great potential in the monitoring of the border intrusion, structural healthy, anti-stealing of pipeline and so on, because of its simple configuration, fast response speed and distributed measuring ability. However, it is difficult to distinguish two vibrations with the same frequency for POTDR because the signal induced by the first vibration would bury the other vibration induced signal. This paper proposes a simple method to resolve this problem in POTDR by analyzing the phase of the vibration induced signal. The effectiveness of this method in distinguishing two vibrations with the same frequency for POTDR is proved by simulation.

A system based on phase-sensitive optical time domain reflectometry is proposed for simultaneously strain and vibration sensing. The strain of fiber is detected by comparing the patterns of signal for different laser frequencies, and the vibration of fiber is detected simultaneously from the signals for any certain laser frequency. During the measurement, frequencies of the probe optical pulses are modulated sequentially in ascending or descending order. Using the signals generated by optical pulses with the same frequency, the vibration of fiber is detected with fast response speed; using that with different frequencies, the strain of fiber is detected with high resolution. In our experiment, a sensing system with 2-m spatial resolution, up to 1-kHz frequency measurement range and 10-ne strain resolution is realized for a 9-km sensing fiber length.

MicroRNAs (miRNAs) are a class of small, noncoding RNA molecules involved in carcinogenesis. It has been identified that genetic variations in miRNAs contribute to cancer risk, prognosis, and survival. In the present study, we investigated whether single nucleotide polymorphisms (SNPs) of several key miRNAs (miR-184, miR-218, and miR-124) were associated with the prognosis of nonsmall cell lung cancer (NSCLC) in a clinical cohort study including 1001 cases. Cox proportional hazards regression models were used to estimate the hazard ratios (HRs) and their 95% confidence intervals (CIs). We found that 5 SNPs were associated with NSCLC survival (rs919968, rs3775815, rs4867902, and rs6122390 in an additive model: adjusted HR = 1.15, 95% CI = 1.02-1.29; adjusted HR = 0.78, 95% CI = 0.67-0.91, adjusted HR = 1.24, 95% CI = 1.09-1.41; adjusted HR = 1.21, 95% CI = 1.07-1.36, respectively; rs298206 in a dominant model: HR = 1.25, 95% CI = 1.05-1.49). Even after the Bonferroni correction, 3 SNPs remained significant (adjusted P = 0.010, 0.010, and 0.032 for rs3775815, rs4867902, and rs6122390, respectively). Additionally, the combined analysis of these 5 SNPs showed a significant locus-dosage effect between number of unfavorable alleles (rs919968-A, rs3775815-C, rs4867902-G, rs6122390-A, and rs298206-T) and death risk of NSCLC (P for trend < 0.001). A statistically significant multiplicative interaction was found between the genotypes of rs4867902 and surgical operation status (Pint = 0.013). These findings indicated that genetic variations in miRNAs (miR-184, miR-218, and miR-124) might be prognostic markers for NSCLC patients.

Exposure to particulate matter 2.5 (PM2.5) may result in DNA damage. Histone variant H2AX phosphorylation plays a central role in the response to damaged chromatin. In the current study, we investigated whether H2AX gene polymorphisms account for PM2.5-modulated DNA damage levels. A total of 307 healthy urban residents were collected from three cities in southern, central, and northern China, Zhuhai, Wuhan, and Tianjin, respectively. The dust mass concentrations of PM2.5 were detected by Gilian 5000 pumps, and the DNA damage levels were measured using comet assay. Seven potentially functional single nucleotide polymorphisms (SNPs) of H2AX gene were selected and genotyped by Illumina Infinium® BeadChip. We found that three SNPs (rs10790283 G>A, rs604714 C>A and rs7759 A>G) were significantly associated with DNA damage levels (adjusted P=0.002, 0.018 and 0.027, respectively). Significant interactions (P<0.05) were observed between certain genetic polymorphisms and PM2.5-modulated DNA damage levels. These results suggested that genetic variations of H2AX might be associated with the DNA damage levels in urban residents with different exposure to PM2.5. Further studies with large sample size in independent populations merit validating these findings.

MicroRNAs (miRNA) are a class of small, noncoding RNA molecules involved in carcinogenesis. Genetic variations in miRNA processing genes may affect the biogenesis of miRNAs, and consequently affect miRNAs regulation and development and progression of human cancer. Therefore, we hypothesized that polymorphisms in two main miRNA biosynthesis genes (DROSHA and DICER) may modulate the survival of advanced non-small cell lung cancer (NSCLC) patients in China. We selected 36 common tagging SNPs in DROSHA and DICER and evaluated the associations of these SNPs with survival of advanced NSCLC patients by a two-stage study in Chinese Han population (discovery cohort: 303 patients; replication cohort: 340 patients). Thirty-six SNPs were detected in the discovery cohort and 12 promising SNPs were validated in the replication cohort. The results showed that DROSHA rs3805525 was marginally associated with the survival of NSCLC patients in the replication cohort (dominant model: HR 0.69, 95 % CI 0.46–1.03, P = 0.071), which was in the same direction as that in the discovery cohort. When combing all patients into one group, three SNPs (rs3805525, rs17410035 and rs7719497) in DROSHA showed significantly associations with NSCLC survival (additive model: HR 0.82, 95 % CI 0.68–0.99 for rs3805525; HR 0.79, 95 % CI 0.62–1.00 for rs17410035; HR 0.76, 95 % CI 0.62–0.93 for rs7719497). Additionally, the combined analysis of those three SNPs showed a significant locus-dosage effect between number of favorable alleles and death risk of NSCLC (Trend P = 0.002). Genetic variations in DROSHA might be associated with the survival of advanced NSCLC patients in Chinese population.

Lung cancer, especially non-small cell lung cancer (NSCLC), is the leading cause of cancer-related deaths all over the world. Studies have indicated that molecular biomarkers, including genetic variants, may provide additional values for the targeted treatments and clinical outcomes of NSCLC patients. To better understand the effects of molecular biomarkers on the treatment of NSCLC, we conducted a genome-wide analysis to investigate the prognostic implications of genetic variants in early-stage NSCLC patients with surgery.

Exposure to particulate matter (e.g., PM2.5) may result in DNA damage, a major culprit in mutagenesis and environmental toxicity. DNA damage levels may vary among individuals simultaneously exposed to PM2.5, however, the genetic determinants are still unclear. To explore whether PM2.5 exposure and genetic variants contribute to the alteration in DNA damage, we recruited 328 subjects from three independent cohorts (119 from Zhuhai, 123 from Wuhan and 86 from Tianjin) in southern, central and northern China with different PM2.5 exposure levels. Personal 24-h PM2.5 exposure levels and DNA damage levels of peripheral blood lymphocytes were evaluated. Genotyping were performed using Illumina Human Exome BeadChip with 241,305 single nucleotide variants (SNVs). The DNA damage levels are consistent with the PM2.5 exposure levels of each cohort. A total of 35 SNVs were consistently associated with DNA damage levels among the three cohorts with pooled P values less than 1.00×10(-3) after adjustment for age, gender, smoking status and PM2.5 exposure levels, of which, 18 SNVs together with gender and PM2.5 exposure levels were independent factors contributing to DNA damage. Gene-based test revealed 3 genes significantly associated with DNA damage levels (P=5.11×10(-3) for POLH, P=2.88×10(-3) for RIT2 and P=2.29×10(-2) for CNTN4). Gene ontology (GO) analyses indicated that the identified variants were significantly enriched in DNA damage response pathway. Our findings highlight the importance of genetic variation as well as personal PM2.5 exposure in modulating individual DNA damage levels.

Background: Recently, a genome-wide association study conducted in Chinese reported a single nucleotide polymorphism at KIF1B, rs17401966, associated with the susceptibility of hepatitis B virus-related hepatocellular carcinoma. In this study, we aim to investigate the effect of rs17401966 on the prognosis of hepatitis B virus-related hepatocellular carcinoma patients at intermediate or advanced stages.Methods: The SNP rs17401966 was genotyped using the TaqMan allelic discrimination assay in 414 intermediate or advanced hepatocellular carcinoma patients. Log-rank test and Cox proportional hazard models were used for survival analyses.Results: Previous studies have identified that the G allele of rs17401966 demonstrated protective effect for the susceptibility of hepatitis B virus-related hepatocellular carcinoma. Here we found that subjects carrying the G allele of rs17401966 was significantly associated with a better survival compared with those carrying the A allele (adjusted hazard ratio = 0.82, 95% confidence intervals = 0.68-0.99, P = 0.044 in an additive genetic model).Conclusion: The variant G allele of rs17401966 may be a favorable biomarker for the prognosis of intermediate or advanced hepatitis B virus-related hepatocellular carcinoma patients in this Chinese population. (C) 2014 Elsevier Ltd. All rights reserved.