Nitric oxide detection using principal component analysis spectral structure matching to the UV derivative spectrum.

Ultraviolet (UV) spectroscopy is widely applied in real-time environmental monitoring, especially in diesel vehicle nitrogen monoxide (NO) emissions. However, in field experiments, UV absorption spectrum may exist for different degrees of drifts. Spectral jitters may exist for various reasons such as optical power variation, electrical signal drift, and the refractive index jitters of the optical path for an extended period of time, which causes the detection system to be calibrated. And the pulse xenon lamps as the UV source are characterized by specific emission lines that interfere in spectral analysis directly. For these problems, we proposed the spectral structure matching method based on principal component analysis (PCA), which was compared with the conventional polynomial fitting method to observe feasibility and variability. Further, the UV derivative spectrum was applied to the system appropriately, due to the variation of the absorption peak, and was only related to the target gas by using the above method. We validated our method experimentally by performing the NO UV detection system with the calibration and the comparison test. The results suggested that the calibration relative error was less than 9% and the measurement relative error was less than 6% for this wide range by the proposed processes, which optimized the interference of spectral structures and fluctuation to the system and therefore provided better monitoring. This study may provide an alternative spectral analysis method that is unaffected on the specific emission lines of lamps and is not limited to the spectral region and the target gas.

Hsa_circ_0001361 facilitates the progress of lung adenocarcinoma cells via targeting miR-525-5p/VMA21 axis.

BACKGROUND: Lung adenocarcinoma (LUAD) is a common subtype of lung cancer with high recurrence rate and fatality. Circ_0001361 has been recognized as key regulators in various malignancies, but its roles in LUAD remain ambiguous. METHODS: Circ_0001361, miR-525-5p, and VMA21 levels were assessed by RT-qPCR. The growth and metastasis of LUAD cells were detected by MTT, colony formation, wound scratch, and transwell assays, respectively. The interaction between circ_0001361/VMA21 and miR-525-5p was detected by dual luciferase, RNA immunoprecipitation, and RNA pull-down assays. VMA21 protein level was detected by Western blotting. Nude mouse xenograft model was established to determine the role of circ_0001361 in tumor growth in vivo. RESULTS: Circ_0001361 was up-regulated, while miR-525-5p was down-regulated in LUAD tissues and cells. Functional experiments demonstrated that circ_0001361 drove LUAD cell growth and metastasis. Mechanistically, circ_0001361 functioned as a sponge of miR-525-5p to up-regulate downstream target VMA21 level. MiR-525-5p/VMA21 axis was involved in circ_0001361-mediated malignant phenotypes of LUAD cells. Finally, inhibition of circ_0001361 restrained in vivo xenograft tumor growth via regulating miR-525-5p/VMA21 axis. CONCLUSION: Our findings elucidate that circ_0001361 facilitates the tumorigenesis and development of LUAD through miR-525-5p/VMA21 axis, providing evidence for circ_0001361 as a potential prognosis biomarker and therapeutic target for clinical treatment of LUAD.

Adaptive monostable stochastic resonance for processing UV absorption spectrum of nitric oxide.

When ultraviolet (UV) absorption spectroscopy technology is used for nitric oxide (NO) detection, the background noise will directly affect the accuracy of concentration inversion, especially in low concentrations. Traditional processing methods attempt to eliminate background noise, which damages the absorption spectrum characteristics. However, stochastic resonance (SR) can utilize the noise to extract a weak characteristic signal. This paper reports a monostable stochastic resonance (MSR) model for processing an UV NO absorption spectrum. By analyzing the characteristics of UV absorption spectrum of NO, the evaluation indexes were constructed, thereby an adaptive MSR method was designed for parameter optimization. The numerical simulation confirmed the absorbance peak can be amplified and spectral signal-to-noise ratio (SNR) can be in the stable range of the proposed method, when noise intensity increased. Finally, this experiment obtained a NO detection limit (3σ) of 1.456 ppm and the maximum relative deviation of concentration is 6.32% by this proposed method, which is satisfactory for processing of the UV NO absorption spectrum.

US-guided microwave ablation for primary hyperparathyroidism: a safety and efficacy study.

OBJECTIVES: To evaluate the safety and efficacy of microwave ablation (MWA) with the assistance of continuous cool saline injection (CCSI) in patients with primary hyperparathyroidism (PHPT). METHODS: Between November 1, 2014, and February 29, 2016, 22 patients with PHPT were enrolled and treated with ultrasound-guided MWA assisted by CCSI. The levels of parathyroid hormone (PTH) and serum calcium were recorded before and after the MWA. Patients were divided into two groups (normalized and unnormalized groups) according to treatment efficacy. Fisher's exact test and the Mann-Whitney test were used to compare data between the two groups. Timing differences in serum PTH and calcium levels were analyzed with repeated measures analysis of variance. RESULTS: Normalized outcomes for both PTH and calcium levels were achieved in 19 of 22 (86.36%) patients with PHPT. In the normalized group, PTH levels remained normal for 12 months after MWA. PTH levels in the unnormalized group were outside the reference range at six of seven follow-ups within 12 months following MWA. By contrast, serum calcium levels gradually decreased in all patients in both groups. The mean serum PTH and mean calcium levels at 6 months after therapy were significantly lower than those before MWA (both p < 0.05). A transient voice change developed in eight patients. One patient experienced hypocalcaemia, which was corrected by oral calcium supplementation within 2 months. CONCLUSIONS: US-guided MWA assisted by CCSI is safe and effective for destroying parathyroid gland tissue and may serve as a therapeutic alternative for patients with PHPT. KEY POINTS: • Microwave ablation is a new option for patients with hypercalcemic or normocalcemic primary hyperparathyroidism. • Microwave ablation can decrease PTH and calcium levels with sustained efficacy in most patients. • Treatment is safe and causes only transient side effects.

Research on the spectral phase correction method for the atmospheric detection in open space.

During the atmospheric detection process in open space, the excessive phase noise is introduced into the signal, due to the atmospheric turbulence, which causes the intensity and phase fluctuation. In the previous study, a spectral data processing method based on the co-frequency and dual-wave has been used to reduce the influence of the scintillation noise from the atmospheric turbulence in open space, while the influence of the phase noise remains to be solved. So the wavelength modulated signal is theoretically analyzed at first. On studying the relationship between the dual-waves in one cycle to eliminate the phase fluctuation and reduce the phase fluctuation caused by the atmospheric turbulence, a new method of the spectral phase correction for the open space atmospheric detection has been proposed. An atmospheric detection experiment on the phase correction in the open space based on co-frequency and dual-wave has been carried out. The results show that the maximum fluctuation of the spectral signal processed with this method is 1.06%, while the power spectral density fluctuation is suppressed below 50Hz, and the Allan analysis result is 8.8 × 10-8(1s). Compared with the traditional concentration inversion method using 2f-wavelength modulation and the classical light intensity elimination, the proposed phase correction method can effectively reduce the fluctuation of random noise caused by the short-term atmospheric turbulence and the laser flashing to improve the stability of the concentration measurement, which has practical engineering value.