Construction and validation of a risk-prediction model for anastomotic leakage after radical gastrectomy: A cohort study in China

Objectives:Anastomotic leakage(AL)stands out as a prevalent and severe complication following gastric cancer surgery.It frequently precipitates additional serious complications,significantly influencing the overall survival time of patients.This study aims to enhance the risk-assessment strategy for AL following gastrectomy for gastric cancer.Methods:This study included a derivation cohort and validation cohort.The derivation cohort included patients who underwent radical gastrectomy at Sir Run Run Shaw Hospital,Zhejiang University School of Medicine,from January 1,2015 to December 31,2020.An evidence-based predictor questionnaire was crafted through extensive literature review and panel discussions.Based on the questionnaire,inpatient data were collected to form a model-derivation cohort.This cohort underwent both univariate and multivariate analyses to identify factors associated with AL events,and a logistic regression model with stepwise regression was developed.A 5-fold cross-validation ensured model reliability.The validation cohort included patients from August 1,2021 to December 31,2021 at the same hospital.Using the same imputation method,we organized the validation-queue data.We then employed the risk-prediction model constructed in the earlier phase of the study to predict the risk of AL in the subjects included in the validation queue.We compared the predictions with the actual occurrence,and evaluated the external validation performance of the model using model-evaluation indicators such as the area under the receiver operating characteristic curve(AUROC),Brier score,and calibration curve.Results:The derivation cohort included 1377 patients,and the validation cohort included 131 patients.The independent predictors of AL after radical gastrectomy included age65 y,preoperative albumin<35 g/L,resection extent,operative time240 min,and intraoperative blood loss90 mL.The predictive model exhibited a solid AUROC of 0.750(95%CI:0.694e0.806;p<0.001)with a Brier score of 0.049.The 5-fold cross-validation confirmed these findings with a calibrated C-index of 0.749 and an average Brier score of 0.052.External validation showed an AUROC of 0.723(95%CI:0.564e0.882;p?0.006)and a Brier score of 0.055,confirming reliability in different clinical settings.Conclusions:We successfully developed a risk-prediction model for AL following radical gastrectomy.This tool will aid healthcare professionals in anticipating AL,potentially reducing unnecessary interventions.

Boosted sodium ion storage performance in MnO_(2):Understanding the bond angle-mediated orbital overlap in MnO_(6)units for fast charge transfer

Symmetric six oxygen-coordinated Mn structural units(MnO6)in MnO2 with small Mn–O orbital overlap hamper electron transfer rates during energy storage.Herein,we report a novel bond angle modulation strategy to manipulate Mn–O orbital overlap in MnO2 through the construction of Mn vacancies(MnO2-VMn),aiming at expediting electron transfer,and thus enhancing energy storage performance.Both experimental and theoretical results disclose that the amplification of Mn–O–Mn bond angles exclusively augments the Mn(dx2-y2)-O(py)orbital overlap and triggers the electron redistribution in MnO2-VMn,inducing an augmented Mn dx2-y2 electron occupation.This heightened presence of active electrons in the Mn dx2-y2 orbital paves the way for accelerating electron transfer and ion transfer in MnO2-VMn.Notably,MnO2-VMn delivers an improved specific capacitance of 425 F g−1 at 1 A g−1 and a superior rate capacity of 265 F g−1 at 20 A g−1.Furthermore,an asymmetric supercapacitor(MnO2-VMn//AC ASC)was fabricated,exhibiting a high energy density of 64.3 Wh kg−1 at a power density of 1000 W kg−1.Furthermore,theoretical insights uncover the profound implications of metal–oxygen–metal bond angle regulation on interatomic orbital overlap modulation.These revelations illuminate pathways for the design of advanced energy storage materials.

The Light Weight Design of Mowing Vehicle Frame with a Combined Method

Lightweight frame is very important to engineering machinery. In this paper, a lightweight design method is proposed for a mechanical mowing truck frame. This method combines topological optimization with topology optimization to design the frame successfully. Based on the finite element simulation, the strength analysis of the two working conditions (bending condition and torsion condition) for the mowing vehicle frame is carried out on the basis of satisfying the requirements of the frame work strength. This paper makes a comparative analysis of the frame after the second optimization using the combined method proposed. The comparison results show that the optimized frame meets the strength requirement, and its quality is 34.3% lower than before. The lightweight effect is obvious.

Photocatalytic nitrogen reduction to ammonia:Insights into the role of defect engineering in photocatalysts

Engineering of defects in semiconductors provides an effective protocol for improving photocatalytic N_(2) conversion efficiency.This review focuses on the state-of-the-art progress in defect engineering of photocatalysts for the N_(2) reduction toward ammonia.The basic principles and mechanisms of thermal catalyzed and photon-induced N_(2) reduction are first concisely recapped,including relevant properties of the N_(2) molecule,reaction pathways,and NH3 quantification methods.Subsequently,defect classification,synthesis strategies,and identification techniques are compendiously summarized.Advances of in situ characterization techniques for monitoring defect state during the N_(2) reduction process are also described.Especially,various surface defect strategies and their critical roles in improving the N_(2) photoreduction performance are highlighted,including surface vacancies(i.e.,anionic vacancies and cationic vacancies),heteroatom doping(i.e.,metal element doping and nonmetal element doping),and atomically defined surface sites.Finally,future opportunities and challenges as well as perspectives on further development of defect-engineered photocatalysts for the nitrogen reduction to ammonia are presented.It is expected that this review can provide a profound guidance for more specialized design of defect-engineered catalysts with high activity and stability for nitrogen photochemical fixation.

Prussian blue nanoparticle-loaded microbubbles for photothermally enhanced gene delivery through ultrasound-targeted microbubble destruction

By adsorbing chitosan(CS)-functionalized Prussian blue(PB) nanoparticles(CS/PB NPs) complexing DNA onto the surface of gas encapsulated microbubbles(MBs), a multifunctional gene delivery system of MBs@CS/PB/DNA was fabricated for photothermally enhanced gene transfection through ultrasound-targeted microbubble destruction. CS/PB NPs of(2.69 ± 0.49) nm could complex DNA effectively when the mass ratio was2:1. It was found that MBs@CS/PB/DNA could enhance ultrasound imaging greatly both in vitro and in vivo. In addition, MBs@CS/PB/DNA could be disrupted by applying a higher-intensity ultrasound irradiation to release CS/PB/DNA, which could effectively transform the nearinfrared(NIR) light into heat to assist the uptake of CS/PB/DNA by cells. With the aid of ultrasound irradiation and NIR light irradiation, the gene transfection efficiency was significantly enhanced to(43.08 ± 1.13) %, much higher than polyethylenimine. Moreover, MBs@CS/PB/DNA showed excellent biocompatibility, encouraging the further exploration of MBs@CS/PB/DNA to be a platform for combined ultrasound image, photothermal therapy, drug delivery, and gene therapy.

Wave Propagation in Fluid-Filled Single-Walled Carbon Nanotube Based on the Nonlocal Strain Gradient Theory

A dynamic Timoshenko beam model is established based on the new nonlocal strain gradient theory and slip boundary theory to study the wave propagation behaviors of fluid-filled carbon nanotubes （CNTs） at nanoscale. The nanoscale effects caused by the CNTs and the inner fluid are simulated by the nonlocal strain gradient effect and the slip boundary effect, respectively. The governing equations of motion are derived and resolved to investigate the wave characteristics in detail. The numerical solution shows that the strain gradient effect leads to the stiffness enhancement of CNTs when the nonlocal stress effect causes the decrease in stiffness. The dynamic properties of CNTs are affected by the coupling of these two scale effects. The flow velocity of fluid inside the CNT is increased due to the slip boundary effect, resulting in the promotion of wave propagation in the dynamic system.