Performance analysis of a liquid lens for laser ablation using OCT imaging.

Laser ablation has been used in different surgical procedures to perform precise treatments. Compared with previous free-beam laser delivery systems, flexible-optical-fiber-based systems can deliver laser energy to a curved space, avoiding the requirement of a straight working path to the target. However, the fiber tip maintains direct contact with the tissue to prevent laser divergence, resulting in fiber damage, uneven ablation, and tissue carbonization. Here, a liquid lens is used to address the problem of laser defocusing when radiating targets at different depths for flexible-optical-fiber-based systems. The liquid lens focuses a laser with a maximum power of 3 W onto a medium-density fiberboard at a focal length of 40-180 mm. The relationships between the ablation crater diameter and depth with the radiation time and laser power have been quantitatively evaluated through OCT (optical coherence tomography) imaging. Experiments demonstrate that the liquid lens can continuously focus the high-power laser to different depths, with the advantages of compact size, fast response, light weight, and easy operation. This study explores liquid-lens-based focused laser ablation, which can potentially improve the performance of future medical image-guided laser ablation.

A Practical Tool for Measuring Home-Based Cardiac Rehabilitation Self-Management Behavior: A Multiphase Cross-Sectional Study.

BACKGROUND: Optimal self-management is the key to home-based cardiac rehabilitation for patients with heart disease. At present, there is a lack of a specific assessment tool to evaluate the home-based cardiac rehabilitation self-management behavior in patients with heart disease. Therefore, the aim of this study was to develop the Home-Based Cardiac Rehabilitation Self-Management Scale and validate its psychometric properties among patients with coronary heart disease. METHODS AND RESULTS: A multiphase cross-sectional study was conducted that study covered 3 phases: (1) item generation and revision, (2) item evaluation and preliminary exploration, and (3) assessment of the psychometric properties of the scale. A scale with 21 items was developed to measure the home-based cardiac rehabilitation self-management behavior. The content validity index of the scale was 0.980. In exploratory factor analysis, the 5-factor structure supported by eigenvalues and screen plot explained 74.326% of the total variation. In confirmatory factor analysis, all fitting indicators were acceptable, further supporting the construct validity of the scale. The criterion validity of the scale was 0.783. In the reliability analysis, the Cronbach's α coefficient of the scale was 0.882, with a dimensionality range of 0.780 to 0.936. The split-half reliability coefficient and test-retest reliability coefficient were 0.774 and 0.770, respectively. CONCLUSIONS: This study is the first to develop and validate a practical tool. This scale can comprehensively and accurately assess the self-management behavior of patients with heart disease in a home-based cardiac rehabilitation environment.

Deep learning-assisted 3D laser steering using an optofluidic laser scanner.

Laser ablation is an effective treatment modality. However, current laser scanners suffer from laser defocusing when scanning targets at different depths in a 3D surgical scene. This study proposes a deep learning-assisted 3D laser steering strategy for minimally invasive surgery that eliminates laser defocusing, increases working distance, and extends scanning range. An optofluidic laser scanner is developed to conduct 3D laser steering. The optofluidic laser scanner has no mechanical moving components, enabling miniature size, lightweight, and low driving voltage. A deep learning-based monocular depth estimation method provides real-time target depth estimation so that the focal length of the laser scanner can be adjusted for laser focusing. Simulations and experiments indicate that the proposed method can significantly increase the working distance and maintain laser focusing while performing 2D laser steering, demonstrating the potential for application in minimally invasive surgery.

A scale for measuring home-based cardiac rehabilitation exercise adherence: a development and validation study.

BACKGROUND: The benefits of home-based cardiac rehabilitation exercise are well-established and depend on long-term adherence. However, there is no uniform and recognized cardiac rehabilitation criterion to assess home-based cardiac rehabilitation exercise adherence for patients with cardiovascular disease. This study aimed to develop a home-based cardiac rehabilitation exercise adherence scale and to validate its psychometric properties among patients with chronic heart failure. METHODS: The dimensions and items of the scale were created based on grounded theory research, literature content analysis, and defined by a Delphi survey. Item analysis was completed to assess the discrimination and homogeneity of the scale. Factor analysis was adopted to explore and validate the underlying factor structure of the scale. Content validity and calibration validity were evaluated using the Delphi survey and correlation analysis, respectively. Reliability was evaluated by Cronbach's α coefficients, split-half reliability coefficients, and test-retest reliability coefficients. RESULTS: A scale covering four dimensions and 20 items was developed for evaluating home-based cardiac rehabilitation exercise adherence. The content validity index of the scale was 0.986. In exploratory factor analysis, a four-factor structure model was confirmed, explaining 75.1% of the total variation. In confirmatory factor analysis, the four-factor structure was supported by the appropriate fitting indexes. Calibration validity of the scale was 0.726. In terms of reliability, the Cronbach's α coefficient of the scale was 0.894, and the Cronbach's α coefficients of dimensions ranged from 0.848 to 0.914. The split-half reliability coefficient of the scale was 0.695. The test-retest reliability coefficient of the scale was 0.745. CONCLUSION: In this study, a home-based cardiac rehabilitation exercise adherence scale was developed and its appropriate psychometric properties were confirmed.

Psychometric Evaluation of the Chinese Version of Occupational LowBack Pain Prevention Behaviors Questionnaire Among Clinical Nurses: A Validation Study.

Objective: This study aimed to translate and validate of the Chinese version of the Occupational Low Back Pain Prevention Behaviors Questionnaire among clinical nurses. Methods: A total of 1,186 clinical nurses were recruited from three provinces in northeast China. The reliability of the translated questionnaire was measured by internal consistency, split-half reliability, and test-retest reliability. The validity of the translated questionnaire was evaluated by content validity index, exploratory factor analysis and confirmatory factor analysis. Results: The Cronbach's α value of the questionnaire was 0.891, and the coefficient values for the six domains ranged between 0.804 and 0.917. The split-half reliability and test-retest reliability were 0.663 and 0.734, respectively. Furthermore, the content validity index of the questionnaire was 0.938. The 6-factor structure, supported by the eigenvalues, total variance explained, and scree plot accounted for 63.038% of the total variance. In the confirmatory factor analysis, as the results of model fitting, χ2/df = 3.753, RMSEA = 0.048, GFI = 0.929, AGFI = 0.913, TLI = 0.934, IFI = 0.943, CFI = 0.943, PGFI = 0.759, PNFI = 0.807. Conclusion: The Chinese version of the Occupational Low Back Pain Prevention Behaviors Questionnaire had suitable reliability and validity among clinical nurses. Under the high prevalence of occupational low back pain, the questionnaire can provide a reference for developing educational intervention plans among clinical nurses.

Association between levels of aquaporin 3 in the placenta and adiponectin in the umbilical cord blood with gestational diabetes mellitus and pregnancy outcome.

Pregnant women with gestational diabetes mellitus (GDM) may have adverse pregnancy outcomes, even if their blood glucose level is well­controlled. Aquaporin 3 (AQP3) and adiponectin (APN) serve important roles in fetal growth and development. However, the associations of AQP3 and APN with GDM and pregnancy outcome are not known. Therefore, the present study was performed to evaluate the expression of AQP3 in the placenta and APN in the umbilical artery blood, and the association of the two factors with GDM and pregnancy outcome. The patient cohort was divided into two groups: Pregnant women with GDM; and pregnant women with normal glucose tolerance (NGT). The expression levels of AQP3 in the placenta and APN in the umbilical artery blood were detected. Logistic regression was used to analyze the associations of AQP3 and APN with GDM and pregnancy outcome. The expression levels of AQP3 and AQP3 mRNA in the placenta of the GDM group were decreased compared with that of the NGT group, and the difference was statistically significant (P<0.05). The expression of APN in the umbilical artery blood of the GDM group was also decreased compared with that of the NGT group, and the difference was also statistically significant (P<0.05). Multivariate logistic regression analyses indicated that the AQP3 and APN levels were negatively correlated not only with the risk of developing GDM [AQP3 odds ratio (OR)=5.00 (P<0.01); APN OR=2.98 (P=0.01)], but also with abnormal pregnancy outcome [(AQP3 OR=4.64 (P<0.01); APN OR=5.41 (P<0.01)]. The levels of AQP3 in the placenta and APN in the umbilical cord blood were associated with GDM, and the risk of GDM was increased in pregnant women with decreased AQP3 and APN levels. The AQP3 and APN levels also had an effect on pregnancy outcome. The risk of abnormal pregnancy outcomes, including cesarean section, macrosomia, fetal distress and neonatal asphyxia, was increased in pregnant women with decreased AQP3 and APN levels.

Realization of Hollow-Core Photonic-Crystal Fiber Optic Gyro Based on Low-Noise Multi-Frequency Lasers with Intermediate-Frequency Difference.

Mainly focusing on the demand for a novel resonator optic gyro based on a hollow-core photonic-crystal fiber (HC-RFOG), we achieve a multi-frequency lasers generation with low relative phase noise via an acousto-optic modulation of light from a single laser diode. We design a homologous heterodyne digital optical phase-locked loop (HHD-OPLL), based on which we realize the low-noise multi-frequency lasers (LNMFLs) with an intermediate frequency difference. The noise between the lasers with a 20 MHz difference is 0.036 Hz, within the bandwidth of 10 Hz, in a tuning range of 120 kHz, approximately 40 dB lower than that produced without the HHD-OPLL. Finally, based on the LNMFLs, an HC-RFOG is realized and a bias stability of 5.8 °/h is successfully demonstrated.

Resonant fiber optic gyroscope with three-frequency differential detection by sideband locking.

A new scheme of three-frequency differential detection with a sideband locking technique is firstly proposed to suppress backscattering noise for improving the accuracy of resonator fiber optic gyroscope (RFOG). In the system we proposed, one light path is divided into three paths and sinusoidal wave modulations of different frequencies are respectively applied to generate the sideband. The first-order sidebands of the three channels of light in the cavity are locked to the adjacent three resonance peaks by sideband locking technique. The carrier and the remaining sidebands of the three channels of light are moved to a position away from the resonance peak, thereby achieving the purpose of being suppressed by the cavity itself. As a result, the frequency difference between the CW light and the other two CCW lights reaches one free spectral range (FSR), eliminating the expected backscattering noise. The experimental results demonstrate that the RFOG has a bias stability 0.9°/h based on the Allan deviation, and the corresponding angular random walk (ARW) 0.016°/√h, which validate that our scheme can effectively suppress backscattering noise to promote performance of RFOG in practical applications.

Design of low-crosstalk polarizing resonator and homologous multi-frequency differential detection for hollow-core photonic-crystal fiber optic gyro.

In order to suppress the undesired polarization in the hollow-core photonic-crystal fiber (HCPCF) resonator and reduce the loss of the resonator, we realize a low-crosstalk polarizing resonator with the polarization-correlated phase modulation technique (PCPM). In addition, we put forward a homologous multi-frequency differential detection scheme, with which the backscattering noise and the backreflection noise of the gyro can be well suppressed. Finally, we realize a hollow-core photonic-crystal fiber optic gyro based on the low-crosstalk polarizing resonator and the homologous multi-frequency differential detection. With this novel gyro system, a bias stability of 1.23°/h is successfully demonstrated.

Free spectral range measurement using homologous heterodyne optical phase-locked loop based on acousto-optic modulation.

We demonstrate a homologous heterodyne optical phase-locked loop for free spectral range measurement of a fiber ring resonator. In this loop, the frequency noise within the 10 Hz bandwidth is reduced by more than 40 dB from 147.350 to 0.014 Hz, and the power spectral density of the frequency noise reaches 7.69×10-8 Hz2/Hz at 10 Hz. Finally, the relative measurement accuracy of 1.39×10-9 is achieved by this loop and the free spectral range coefficient of thermal expansion is measured as -174.1±0.2 Hz/°C with a cavity finesse of 26.65. This work provides a method to measure free spectral range by tracking the resonance modes of the resonator and reducing frequency noise, especially for two signals with frequency offset.

Sevoflurane relieves hepatic ischemia-reperfusion injury by inhibiting the expression of Grp78.

Purpose: This article aimed to study the role of sevoflurane pre-conditioning in hepatic ischemia-reperfusion and its potential mechanism.Methods: Rat liver ischemia-reperfusion model was constructed. Serum TNF-α, IL-1ß, IL-10, and IL-6 concentrations were detected by ELISA. Malondialdehyde (MDA), superoxide dismutase (SOD), and nitric oxide (NO) in liver homogenate were determined. Hematoxylin-Eosin (HE) staining, Tunel, and immunohistochemistry were performed. Ischemia-reperfusion hepatocyte model was established. Cells transfection was conducted. Apoptosis was observed by flow cytometry. Quantitative real-time PCR (qRT-PCR) and Western blotting analysis were used.Results: Compared with I/R group, liver damage degree, liver cell apoptosis, and glucose regulatory protein 78 (Grp78) expression was obviously reduced in rats of SEV group. TNF-α, IL-1ß, and IL-6 concentrations were also significantly increased (P<0.01). MDA and NO concentrations were dramatically lower (P<0.01) and SOD concentration was significantly higher (P<0.01). Apoptosis rate, Grp78, PERK, eIF2α, and p-c-JNK/JNK expression was also significantly decreased (P<0.01). Sevoflurane significantly reduced apoptosis and expression of PERK, eIF2α, p-c-JNK/JNK by inhibiting the expression of Grp78 (P<0.01).Conclusion: Sevoflurane relieves hepatic ischemia-reperfusion injury by inhibiting the expression of Grp78.

[A new loading bioreactor for bone tissue-engineering applications].

Bone cells live in an environment heavily influenced by mechanical force. The development of bone tissue is dependent on the environment that surrounds it, both in vivo and in vitro. A loading stimulator on research of bone tissue-engineering was developed based on the mechanism of mechanosensation, scaffolding composites with mechanical strains with more physiologic magnitude, frequency components, and waveform. It also achieves the mechanical environment particularly in hard scaffold enough strong like cancellous bone. The device was tested using a reference scaffold made of better elastic plastic material. The experiment results showed that the device could be used in precision strain controls. Since the drive of the stimulator comes from the usage of smart material, piezoceramics, the strain at physiological level is controlled precisely. The stimulator provides a mechanical condition under which the effects of loading applied on bone tissue-engineering culture are conveniently investigated. Furthermore, after the stimulator is improved, it will be an appropriate bioreactor for bone tissue-engineering culture.