Comprehensive abdominal composition evaluation of rectal cancer patients with anastomotic leakage compared with body mass indexmatched controls

BACKGROUND Anastomotic leakage(AL)is a fatal complication in patients with rectal cancer after undergoing anterior resection.However,the role of abdominal composition in the development of AL has not been studied.AIM To investigate the relationship between abdominal composition and AL in rectal cancer patients after undergoing anterior resection.METHODS A retrospective case-matched cohort study was conducted.Complete data for 78 patients with AL were acquired and this cohort was defined as the AL group.The controls were matched for the same sex and body mass index(±1 kg/m^(2)).Parameters related to abdominal composition including visceral fat area(VFA),subcutaneous fat area(SFA),subcutaneous fat thickness(SFT),skeletal muscle area(SMA),skeletal muscle index(SMI),abdominal circumference(AC),anterior to posterior diameter of abdominal cavity(APD),and transverse diameter of abdominal cavity(TD)were evaluated based on computed tomography(CT)images using the following Hounsfield Unit(HU)thresholds:SFA:-190 to-30,SMA:-29 to 150,and VFA:-150 to-20.The significance of abdominal compositionrelated parameters was quantified using feature importance analysis;an artificial intelligence method was used to evaluate the contribution of each included variable.RESULTS Two thousand two hundred and thirty-eight rectal cancer patients who underwent anterior resection from 2010 to 2020 in a large academic hospital were investigated.Finally,156 cases were enrolled in the study.Patients in the AL group showed longer operative time(225.03±55.29 vs 207.17±40.80,P=0.023),lower levels of preoperative hemoglobin(123.32±21.17 vs 132.60±16.31,P=0.003)and albumin(38.34±4.01 vs 40.52±3.97,P=0.001),larger tumor size(4.07±1.36 vs 2.76±1.28,P<0.001),and later cancer stage(P<0.001)compared to the controls.Patients who developed AL exhibited a larger VFA(125.68±73.59 vs 97.03±57.66,P=0.008)and a smaller APD(77.30±23.23 vs 92.09±26.40,P<0.001)and TD(22.90±2.23 vs 24.21±2.90,P=0.002)compared to their matched controls.Feature importance analysis revealed that TD,APD,and VFA were the three most important abdominal composition-related features.CONCLUSION AL patients have a higher visceral fat content and a narrower abdominal structure compared to matched controls.

Synthesis and optical properties of LiNd(PO_3)_4 nanocrystals dispersion in DMSO/TBE

Lanthanide doped nanocrystals with strong fluorescence, long lifetime at high doping concentrations have great potential application in bio-imaging and liquid gain medium. LiNd(PO_3)_4(LNP) crystal was reported to be one of the most excellent laser crystals with high Nd3+ concentration, and their nanocrystals synthesized via improved combustion method for the first time had strong emission intensity and long fluorescence lifetime of 122 μs. Besides,LiNd(PO_3)_4 nanocrystals can be dispersed in mixed solvents of DMSO/TBE(CHBr2 CHBr2) to form a transparent colloidal dispersion, and Judd-Ofelt theory was used to evaluate their optical parameters. In summary, LiNd(PO_3)_4 nanocrystals possess long lifetime(116 μs), low solvents quenching rate(4.9%), large emission cross section(7.63 × 10^(-20) cm^2) and high quantum yield(35.2%) under high Nd3+ ions concentration(1×10^(20) cm^(-3)), which would be the most competitive colloidal gain medium of optical amplification and laser with LD pump and potential biomaterial with low particles concentration.