Comparison of Various Regional Analgesia Methods for Postoperative Analgesic Effects in Video-assisted Thoracoscopic Surgery: A Systematic Review and Network Meta-analysis.

BACKGROUND: The optimal analgesia for video-assisted thoracoscopic surgery (VATS) is still unknown. OBJECTIVES: Our aim was to conduct a network meta-analysis and systematic review to compare the efficacy of different analgesic strategies in VATS. STUDY DESIGN: Bayesian network meta-analysis. METHODS: We searched PubMed, Embase, Medline, Springer, Google Scholar, and Web of Science to evaluate all relevant randomized controlled trials that investigated the analgesic effects of different regional analgesia methods for VATS published through July 2021. After a comprehensive search of electronic databases, the following methods were identified: epidural analgesia (EA), local anesthetics (LA), superficial serratus anterior plane block (SSAPB), deep serratus anterior plane block (DSAPB), erector spinae plane block (ESPB), paravertebral block (PVB), and intercostal nerve block (ICNB). Primary outcomes were the visual analog scale score at rest, at 2 hours, 6 hours and 24 hours postoperatively. The secondary outcomes were postoperative analgesic consumption, incidence of nausea and emesis, and pruritus. RESULT: Overall, 35 trials met our inclusion criteria. EA and PVB were relatively more advantageous in terms of analgesic effect at 2 hours and 6 hours postoperatively; the EA group was superior to the DSAPB, ESPB, and ICNB groups at 24 hours postoperatively. EA was found to be superior to other analgesia techniques for 24 hour postoperative analgesic consumption., PVB showed advantages in reducing postoperative nausea, emesis, and pruritus. LIMITATIONS: Different concentrations and volumes of local anesthetics might affect the analgesic effects of the various analgesia techniques. CONCLUSION: EA and PVB have certain advantages in analgesia, but the incidence of postoperative pruritus after EA is higher. At the same time, considering the risk of coagulation and puncture complications, PVB may be a better choice.

MRI magnetic compatible electrical neural interface: From materials to application.

Neural electrical interfaces are important tools for local neural stimulation and recording, which potentially have wide application in the diagnosis and treatment of neural diseases, as well as in the transmission of neural activity for brain-computer interface (BCI) systems. At the same time, magnetic resonance imaging (MRI) is one of the effective and non-invasive techniques for recording whole-brain signals, providing details of brain structures and also activation pattern maps. Simultaneous recording of extracellular neural signals and MRI combines two expressions of the same neural activity and is believed to be of great importance for the understanding of brain function. However, this combination makes requests on the magnetic and electronic performance of neural interface devices. MRI-compatibility refers here to a technological approach to simultaneous MRI and electrode recording or stimulation without artifacts in imaging. Trade-offs between materials magnetic susceptibility selection and electrical function should be considered. Herein, prominent trends in selecting materials of suitable magnetic properties are analyzed and material design, function and application of neural interfaces are outlined together with the remaining challenge to fabricate MRI-compatible neural interface.

Comparative evaluation of the clinical safety and efficiency of supraclavicular and infraclavicular approaches for subclavian venous catheterization in adults: A meta-analysis.

BACKGROUND: In this meta-analysis, we investigated the success rate of subclavian venous catheterization (SVC) as well as the incidence of related complications when performed via the supraclavicular (SC) or traditional infraclavicular (IC) approaches. METHODS: Ignoring the original language, we identified and analyzed eight randomized controlled trials (RCTs) published on or before December 30, 2018, after searching the following five bibliographic databases: PubMed, Springer, Medline, EMBASE, and the Cochrane Library. All included studies compared the clinical safety and efficiency of the SC and IC approaches for SVC in adults. The Cochrane Collaboration's Risk of Bias Tool was used to evaluate the methodological quality of each RCT. Cannulation failure rates and the incidence of malposition were regarded as the primary outcome measures. Secondary outcome measures included cannulation access time and the incidence of pneumothorax and artery puncture. RESULTS: Failure rates were significantly lower for SVC via the SC approach than via the IC approach [odds ratio, 0.66; 95% confidence interval (CI), 0.47 to 0.93]. The SC approach was also associated with a decreased incidence of catheter malposition, relative to that observed for the IC approach [odds ratio, 0.24; 95% CI, 0.13 to 0.46]. The SC approach did not reduce the time required for cannulation [mean difference, -74.74; 95% CI, -157.80 to 8.33], and there were no differences in the incidence of artery puncture [odds ratio, 0.60; 95% CI, 0.29 to 1.23] or pneumothorax [odds ratio, 0.89; 95% CI, 0.33 to 2.40]. CONCLUSION: Our findings suggest that SVC via the SC approach should be utilized in adults.

[Analysis and Design of Interference Imaging System in Fourier Transform Imaging Spectrometer Based on Multi-Micro-Mirror].

To realize the static state and high throughput of Fourier transform imaging spectrometer (FTIS), a temporal spatial mixed modulated FTIS based on multi-micro-mirror was put forward in this paper, whose interference system was based on Michelson interferometer with a multi-micro-mirror to replace the plane mirror. The remarkable characteristics of this FTIS were no movable parts and slit existing in this system, and the interferogram and image of object could be gained at the same time. The fore-optics system imaged the object on the plane mirror and multi-micro-mirror of the interference system, due to the structure feature of multi-micro-mirror, the optical path difference (OPD) of two imaging beam could be modulated. Through the reimaging system, the image of object with different interference order could be obtained. By means of the analysis to the spectrum signal-to-noise ratio (SNR) of interference system, the relationship between spectrum SNR and image SNR was definite, and the characteristic parameters of multi-micro-mirror were determined. To ensure the constancy of OPD corresponding to each step plane, by means of the analysis to the imaging process of fore-optics system, the optical path structure of telecentric in image space was determined. According to the calculation of the relationship between field of view and OPD, the design indexes of fore-optics system were determined and the optical design was completed. To ensure no extra OPD was introduced by reimaging system, through the analysis of the imaging feature by reimaging system, the optical path structure of double telecentric was determined. According to the calculation of the relationship between incidence aperture angle and step number, the optical system that satisfied the system requirement was designed. By means of the theory analysis and optical design to each unit system, this research can provide a novel development strategy for static and high throughput FTIS.

[A new peak detection algorithm of Raman spectra].

The authors proposed a new Raman peak recognition method named bi-scale correlation algorithm. The algorithm uses the combination of the correlation coefficient and the local signal-to-noise ratio under two scales to achieve Raman peak identification. We compared the performance of the proposed algorithm with that of the traditional continuous wavelet transform method through MATLAB, and then tested the algorithm with real Raman spectra. The results show that the average time for identifying a Raman spectrum is 0.51 s with the algorithm, while it is 0.71 s with the continuous wavelet transform. When the signal-to-noise ratio of Raman peak is greater than or equal to 6 (modern Raman spectrometers feature an excellent signal-to-noise ratio), the recognition accuracy with the algorithm is higher than 99%, while it is less than 84% with the continuous wavelet transform method. The mean and the standard deviations of the peak position identification error of the algorithm are both less than that of the continuous wavelet transform method. Simulation analysis and experimental verification prove that the new algorithm possesses the following advantages: no needs of human intervention, no needs of de-noising and background removal operation, higher recognition speed and higher recognition accuracy. The proposed algorithm is operable in Raman peak identification.

[Influence of collimation system on static Fourier transform spectrometer].

Collimation system provides collimated light for the static Fourier-transform spectroscopy (SFTS). Its quality is crucial to the signal to noise ratio (SNR) of SFTS. In the present paper, the physical model of SFTS was established based on the Fresnel diffraction theory by means of numerical software. The influence of collimation system on the SFTS was discussed in detail focusing on the aberrations of collimation lens and the quality of extended source. The results of simulation show that the influences of different kinds of aberrations on SNR take on obvious regularity, and in particular, the influences of off-axis aberrations on SNR are closely related to the location of off-axis point source. Finally the extended source's maximum radius allowed was obtained by simulation, which equals to 0.65 mm. The discussion results will be used for the design of collimation system.

[Study on transmission efficiency of interference system in spatially modulated Fourier transform spectrometer].

The reflection of the optic system surface and the absorption of the infrared material could reduce the transmission of the incident light in spatially modulated Fourier transform infrared spectrometer. Through the calculation of the transmission function of the interference system and the simulation of the interferogram image and recovered spectrum affected by transmission function, it was indicated that the contrast of the interferogram image declined and the spectral line intensity weakened. The theoretical analysis shows that the contrast of the interferogram image was related to the intensity reflectance of the anti-reflection film, and the attenuation of the spectrum was determined by transmission efficiency concerned with intensity reflectance R1 of the anti-reflection film, intensity reflectance R2 of the beam splitter film, and the absorption coefficient. By means of the analysis and argumentation, the absorption of the material could be ignored in our investigative wave band. So the transmission efficiency was determined only by R1 and R2. Then taking the transmission efficiency as the design target, according to the transmission required by system, the tolerance of the R1 and R2 could be gained.

[Analysis of multi-micromirrors tilt error in space-modulated Fourier transform infrared spectrometry].

The system of space-modulated Fourier transform infrared spectrometer without moving parts is stable and compact, moreover, it can realize the on-line monitoring and real-time detection. The position accuracy of multi-micromirrors as the key components has a great influence on spectrometric performance. In the present paper, the multi-mcromirrors tilt error caused by optical path difference changes was calculated and simulated. The analysis shows that, as the multi-micromirrors tilt angle increased, the interference pattern contrast decreased and the signal to noise ratio reduced. The results could be used in the tolerance distribution and the systemic alignment in the next step.

[Study on spectrum inversion of spatially modulated Fourier transform spectrometer].

The sampling mode of static Fourier transform spectrometer is spatial domain sampling. The interferogram function is sampled by two orthogonal stepped mirrors and the interference irradiance is received by the detector. The interferogram image is a planar spatial array which consists of MXM interferogram units. After image segmentation, the interferogram image is divided into M x M interferogram units according to comparability criterion. By means of addressing location, the sampled interferogram sequence which matches up to the discrete optical path difference sequence could be gained. Using over-zero sampling technique, the big single side interferogram sequence and the small double side interferogram sequence are apodizated by different window functions. For the sake of correcting phase error, the frequency-domain spectrum correction and space-domain interferogram correction are researched and improved. The simulation result shows that the two methods can both gain the perfect spectrum line shape, and the effect of space-domain interferogram correction is better than others with the spectrum standard deviation only 0.012 088.

[Study on uniformity of optical field in static Fourier transform spectrometer].

Since the Fourier transform spectrometer based on multi-micro mirrors samples the interferogram image which corresponds to each OPD in the transverse optical field, the spatial distribution of the irradiance has much effect on the quality of the interferogram. In the present paper, distribution function is introduced in this spectrometer system. By means of simulation, the contrast of the interferogram modulated by distribution function is depressed in the fringe area and the concomitant line appears in the spectrum. According to theory analysis, the decline of the contrast lies on the distribution function which scans the interferogram periodically. And the concomitant line is the effect of the spectrum shift, which belongs to the modulation function. Finally, the difference image and conversed recovery arithmetic are proposed. Via the simulation, the conversed recovery arithmetic can recover the interferogram and the spectrum evidently.

[Influence of extended light source on spectral reconstruction in a micro FTIR].

The influence of extended light source on spectral reconstruction in the FTIR (fourier transform infrared spectrometer) based on step mirrors was discussed in the present paper. The relationship between coherent intensity and solid angle was calculated. It was found that the coherent length became shorter and the spectrum resolving power became lower as a result of solid angle produced by the extended light source. The spectrum resolving power of system could reach the value as the theoretic design if the solid angle of extended light source is smaller than 0.001. The radiance will reduce if the size of extended light source is shortened. Therefore, a suitable size of extended light source can be chosen, considering the requirement of SNR in the optical design.

[Analysis of collimation error in Fourier transform infrared spectrometer based on step mirrors].

The collimation error in Fourier transform spectrometer has many effects on the interferogram and the spectrogram. By means of modulation, the authors found the reverse of contrast in the interferogram and the side slope noise in the spectrogram due to the collimation error. The authors analyzed the signal-to-noise ratio and resolution at different factor of beam divergence. When the factor of the beam divergence is 0.15 degrees x mm(-1), the signal-to-noise ratio can reduce to 6 dB and the resolution can go bad to 13.4 cm(-1).

[Study on the gasoline classification methods based on near infrared spectroscopy].

The purpose of the present paper is to study the classification methods of gasoline. First, two classific models are compared using discriminant cluster analysis method in 700-1100 nm and 1100-1700 nm spectral region. The sample is 90#, 93# and 97# gasoline. The results show that the model in 1100-1700 nm spectral region is veracious. And then a new model has been educed based on principal component analysis (PCA) and self-organizing competitive neural networks in order to classify 90#, 93# and 97# gasoline. The spectral data were condensed by PCA method before modeling, and three principal components were chosen because their cumulative credibility had reached 97%. A three-layer self-organizing competitive neural network model was established. Thirty-two wavelengths' absorbance is the concentrated spectral data by PCA method, and served as inputs of the self-organizing competitive neural network. The learning parameter is set as 0.01 and the training iteration is taken as 500. The conclusion is that it is feasible to apply near infrared spectroscopy to discriminate the gasoline products as the PCA and self-organizing competitive neural networks method is used. Also the PCA and self-organizing competitive neural networks method is better than the discriminant cluster analysis method.

[Analysis of diffraction in Fourier-transform infrared spectrometer based on step mirrors].

Diffraction in the Fourier-transform infrared spectrometer based on step mirrors was analyzed in the present paper, and the influence of diffraction on the spectrum reconstruction with different width of step mirrors, wavelengths and distance was also discussed. It is shown that the influence of diffraction is low when the distance is less than 10 cm and the width of mirror is more than 0.5 mm. Also, a method to reduce the noises in spectrum reconstuction is discussed in this paper. The results could be used in the design of the spectrometer and the data processing in the next step.

[The investigation and simulation of a novel spatially modulated micro-Fourier transform spectrometer].

Fourier transform spectrometer (FTS) is widely used in science and industry for the measurement of electromagnetic spectra, and it's trend of minimization is particularly pronounced in many applications. A novel model of a micro FTS with no moving parts is proposed and analyzed. During the analysis, the gradients which mainly introduce the phase error are accounted for in details. Based on these assumptions and the improved Mertz phase correcting method, the spectrum of the signal is simulated, given the real extended light source. The resolution can reach 3.43 nm@800 nm, with high SNR limiting resolving ability 6.8 dB. The novel micro FTS could be made by MOEMS technology, which has some advantages over the conventional micro dispersive spectrometers based on the traditional technology, and this method can also afford some new concepts on the design of spectrometers. The research work is underway to demonstrate the theory.