Robotics in Cervical Spine Surgery: Feasibility and Safety of Posterior Screw Placement.

OBJECTIVE: Robot-assisted (RA) techniques have been widely investigated in thoracolumbar spine surgery. However, the application of RA methods on cervical spine surgery is rare due to the complex morphology of cervical vertebrae and catastrophic complications. Thus, the feasibility and safety of RA cervical screw placement remain controversial. This study aims to evaluate the feasibility and safety of RA screw placement on cervical spine surgery. METHODS: A comprehensive search on PubMed, Cochrane Library, Embase Database, Web of Science, Chinese National Knowledge Databases, and Wanfang Database was performed to select potential eligible studies. Randomized controlled trials (RCTs), comparative cohort studies, and case series reporting the accuracy of cervical screw placement were included. The Cochrane risk of bias criteria and Newcastle-Ottawa Scale criteria were utilized to rate the risk of bias of the included literatures. The primary outcome was the rate of cervical screw placement accuracy with robotic guidance; subgroup analyses based on the screw type and insertion segments were also performed. RESULTS: One RCT, 3 comparative cohort studies, and 3 case series consisting of 160 patients and 719 cervical screws were included in this meta-analysis. The combined outcomes indicated that the rates of optimal and clinically acceptable cervical screw placement accuracy under robotic guidance were 88.0% (95% confidence interval [CI], 84.1%-91.4%; p = 0.073; I2 = 47.941%) and 98.4% (95% CI, 96.8%-99.5%; p = 0.167; I2 = 35.954%). The subgroup analyses showed that the rate of optimal pedicle screw placement accuracy was 88.2% (95% CI, 83.1%-92.6%; p = 0.057; I2 = 53.305%); the rates of optimal screw placement accuracy on C1, C2, and subaxial segments were 96.2% (95% CI, 80.5%-100.0%; p = 0.167; I2 = 44.134X%), 89.7% (95% CI, 80.6%-96.6%; p = 0.370; I2 = 0.000X%), and 82.6% (95% CI, 70.9%-91.9%; p = 0.057; I2 = 65.127X%;), respectively. CONCLUSION: RA techniques were associated with high rates of optimal and clinically acceptable screw positions. RA cervical screw placement is accurate, safe, and feasible in cervical spine surgery with promising clinical potential.

Which Indicator Among Lumbar Vertebral Hounsfield Unit, Vertebral Bone Quality, or Dual-Energy X-Ray Absorptiometry-Measured Bone Mineral Density Is More Efficacious in Predicting Thoracolumbar Fragility Fractures?

OBJECTIVE: Hounsfield units (HU), vertebral bone quality (VBQ), and bone mineral density (BMD) can all serve as predictive indicators for thoracolumbar fragility fractures. This study aims to explore which indicator provides better risk prediction for thoracolumbar fragility fractures. METHODS: Patients who have received medical attention from The First Affiliated Hospital of Anhui Medical University for thoracolumbar fragility fractures were selected. A total of 78 patients with thoracolumbar fragility fractures were included in the study. To establish a control group, 78 patients with degenerative spinal diseases were matched to the fracture group on the basis of gender, age, and body mass index. The lumbar vertebral HU, the VBQ, and the BMD were obtained for all the 156 patients through computed tomography, magnetic resonance imaging, and dual-energy x-ray absorptiometry (DEXA). The correlations among these parameters were analyzed. The area under curve (AUC) analysis was employed to assess the predictive efficacy and thresholds of lumbar vertebral HU, VBQ, and BMD in relation to the risk of thoracolumbar fragility fractures. RESULTS: Among the cohort of 156 patients, lumbar vertebral HU exhibited a positive correlation with BMD (p < 0.01). Conversely, VBQ showed a negative correlation with HU, BMD (p < 0.05). HU and BMD displayed a favorable predictive efficacy for thoracolumbar fragility fractures (p < 0.01), with HU (AUC = 0.863) showcasing the highest predictive efficacy, followed by the DEXA-measured BMD (AUC = 0.813). VBQ (AUC = 0.602) ranked lowest among the 3 indicators. The thresholds for predicting thoracolumbar fragility fractures were as follows: HU (88),VBQ (3.37), and BMD (0.81). CONCLUSION: All 3 of these indicators, HU, VBQ, and BMD, can predict thoracolumbar fragility fractures. Notably, lumbar vertebral HU exhibits the highest predictive efficacy, followed by the BMD obtained through DEXA scanning, with VBQ demonstrating the lowest predictive efficacy.

Effect of aerosols on the macro- and micro-physical properties of warm clouds in the Beijing-Tianjin-Hebei region.

The interaction between aerosols and clouds plays an important role in the climate system. There is still uncertainty about the influences of aerosols on the macro- and micro-physical properties of clouds in the Beijing-Tianjin-Hebei region. The relationships between aerosol optical depth (AOD) and the macro- and micro-physical properties of warm clouds in the Beijing-Tianjin-Hebei region were analyzed based on MODIS/Aqua data from 2007 to 2016. In addition, the ERA-Interim meteorological data was employed to investigate the relationship of AOD and cloud parameters under different meteorological conditions. The results showed that the variation of cloud droplet effective radius (CER) with AOD was in agreement with the Anti-Twomey effect, the main reason was that the increasing aerosol causes the water vapor competition effect among the cloud droplets, which makes the smaller cloud droplets evaporate. The multi-year average AOD was positively correlated with liquid water path (LWP). The relationship between AOD and cloud optical depth (COD) was quite different. When AOD was <0.4 or >0.8, COD increased with the increase of AOD, and when AOD was between 0.4 and 0.8, AOD and COD showed negative correlation. With the increment of AOD, cloud top pressure (CTP) also increased, which indicated that cloud top height decreased. When AOD was <0.3, cloud fraction (CF) was negatively correlated with AOD and conversely, positively correlated when AOD was >0.3. Furthermore, under most meteorological conditions, AOD was positively correlated with cloud macro- and micro-physical properties. Under the conditions of relative humidity ranged from 40% to 80%, there was a negative correlation between AOD and COD.

[Quantitative Analysis of Mn in Soil Based on LIBS with Multivariate Nonlinear Method].

Manganese (Mn) is one of the indispensable micronutrients for plants. The concentration of Mn in soil was determined with laser-induced breakdown spectroscopy (LIBS) in this paper. Forty-six soil samples were used to obtain the spectrum data of LIBS. The characteristic line of 403.1 nm was selected as the analytical line of Mn. The calibration curve of the net intensity of Mn line at 403.1 nm versus the corresponding concentration was constructed withthe correlation coefficient 0.78. The results showed that, due to the complex chemical compositions of soil samples, the calibration method influenced by the matrix effect seriously. It should utilize more information of LIBS spectra to construct the multivariate nonlinear calibration method, which can reduce the matrix effect and improve the measurement accuracy of LIBS. With multivariate nonlinear calibration method, the interference effect of C and Fe elements on the concentration of Mn was considered. Compared with calibration method, the correlation coefficient of the prediction concentration of LIBS with reference concentration was 0.97, and the relative measured error was in the range 3.2%~10.3%,Therefore, the measurement accuracy of LIBS was increased. The experimental results demonstrate that LIBS combined with multivariate nonlinear calibration method can be used to quantitative analysis of Mn in soil.

Structure sensitivity of CO oxidation on Co3O4: a DFT study.

The reaction mechanism of CO oxidation on the Co(3)O(4) (110) and Co(3)O(4) (111) surfaces is investigated by means of spin-polarized density functional theory (DFT) within the GGA+U framework. Adsorption situation and complete reaction cycles for CO oxidation are clarified. The results indicate that 1) the U value can affect the calculated energetic result significantly, not only the absolute adsorption energy but also the trend in adsorption energy; 2) CO can directly react with surface lattice oxygen atoms (O(2f)/O(3f)) to form CO(2) via the Mars-van Krevelen reaction mechanism on both (110)-B and (111)-B; 3) pre-adsorbed molecular O(2) can enhance CO oxidation through the channel in which it directly reacts with molecular CO to form CO(2) [O(2)(a)+CO(g)→CO(2)(g)+O(a)] on (110)-A/(111)-A; 4) CO oxidation is a structure-sensitive reaction, and the activation energy of CO oxidation follows the order of Co(3)O(4) (111)-A(0.78 eV)>Co(3)O(4) (111)-B (0.68 eV)>Co(3)O(4) (110)-A (0.51 eV)>Co(3)O(4) (110)-B (0.41 eV), that is, the (110) surface shows higher reactivity for CO oxidation than the (111) surface; 5) in addition to the O(2f), it was also found that Co(3+) is more active than Co(2+), so both O(2f) and Co(3+) control the catalytic activity of CO oxidation on Co(3)O(4), as opposed to a previous DFT study which concluded that either Co(3+) or O(2f) is the active site.