基于倾向性评分匹配法比较食管癌术后早期肠内营养与肠外营养的疗效

目的:综合评价并比较食管癌术后早期肠内营养(early enteral nutrition,EEN)和肠外营养(total parenteral nutrition,TPN)的临床疗效。方法:回顾性分析2011年3月至2019年3月在首都医科大学附属北京世纪坛医院行食管癌手术的患者237例,依据术后营养方式不同分为EEN组136例和TPN组101例,采用倾向性评分匹配功能进行匹配,比较匹配后两组患者的营养状况、肝功能、胃肠功能恢复情况、术后住院天数及并发症等指标。结果:采用1:1最邻近匹配法,经倾向性评分成功匹配91对患者。EEN组营养指标前白蛋白(prealbumin,PA)在术后7天明显优于TPN组(P<0.05),而白蛋白(albumin,ALB)在术前、术后3、7天与TPN组比较无明显差异;EEN组的肝功能指标谷草转氨酶(ALT)、谷丙转氨酶(AST)在术后3天及7天显著优于TPN组(P<0.05);EEN组在放置胃管时间、排便时间、术后经口进食时间及术后住院天数均明显少于TPN组(P<0.05);EEN组反酸或呕吐、腹泻的发生率高于TPN组,而肺水肿、肺部感染的发生率低于TPN组,差异具有统计学意义(P<0.05)。结论:与TPN相比,食管癌术后应用EEN的反酸或呕吐、腹泻发生率较高,但对肝功能影响小,能促进肠道功能恢复,改善患者的营养状况,缩短住院时间。

Hyperthermic intraperitoneal chemotherapy for gastric cancer with peritoneal metastasis:A multicenter propensity scorematched cohort study

Objective:Systemic chemotherapy has limited efficacy in the treatment of peritoneal metastasis(PM)in gastric cancer(GC).Hyperthermic intraperitoneal chemotherapy(HIPEC)combined with complete cytoreductive surgery(CRS)has shown promising outcomes but remains controversial.The present study aimed to evaluate the safety and efficacy of HIPEC without CRS in GC patients with PM.Methods:This retrospective propensity score-matched multicenter cohort study included GC patients with PM treated with either chemotherapy alone(Cx group)or with HIPEC combined with chemotherapy(HIPEC-Cx group)in four Chinese high-volume gastric medical centers between 2010 and 2017.The primary outcomes were median survival time(MST)and 3-year overall survival(OS).Propensity score matching was performed to compensate for controlling potential confounding effects and selection bias.Results:Of 663 eligible patients,498 were matched.The MST in the Cx and HIPEC-Cx groups was 10.8 and 15.9 months,respectively[hazard ratio(HR)=0.71,95%confidence interval(95%CI),0.58-0.88;P=0.002].The 3-year OS rate was 10.1%(95%CI,5.4%-14.8%)and 18.4%(95%CI,12.3%-24.5%)in the Cx and HIPEC-Cx groups,respectively(P=0.017).The complication rates were comparable.The time to first flatus and length of hospital stay for patients undergoing HIPEC combined with chemotherapy was longer than that of chemotherapy alone(4.6±2.4 d vs.2.7±1.8 d,P<0.001;14.2±5.8 d vs.11.4±7.7 d,P<0.001),respectively.The median follow-up period was 33.2 months.Conclusions:Compared with standard systemic chemotherapy,HIPEC combined with chemotherapy revealed a statistically significant survival benefit for GC patients with PM,without compromising patient safety.

Novel Boron Nitride Polymorphs with Graphite-Diamond Hybrid Structure

Both boron nitride(BN)and carbon(C)have sp,sp^(2)and sp^(3)hybridization modes,thus resulting in a variety of BN and C polymorphs with similar structures,such as hexagonal BN(hBN)and graphite,cubic BN(cBN)and diamond.Here,five types of BN polymorph structures are proposed theoretically,inspired by the graphite-diamond hybrid structures discovered in a recent experiment.These BN polymorphs with graphite-diamond hybrid structures possess excellent mechanical properties with combined high hardness and high ductility,and also exhibit various electronic properties such as semi-conductivity,semi-metallicity,and even one-and two-dimensional conductivity,differing from known insulators hBN and cBN.The simulated diffraction patterns of these BN hybrid structures could account for the unsolved diffraction patterns of intermediate products composed of so-called“compressed hBN”and diamond-like BN,caused by phase transitions in previous experiments.Thus,this work provides a theoretical basis for the presence of these types of hybrid materials during phase transitions between graphite-like and diamond-like BN polymorphs.

Smoking Cause Specific Lung Cancer—Evidence from Non-Smoking Lung Adenocarcinoma

Introduction: Smoking and non-smoking lung cancer have many differences in clinical feature. But those may be the result of interference due to differences in pathological type, as most smoking patients suffer squmous cell lung cancer and non-smokings tend to get adenocarcinoma. This study was conducted on the specific histological type-lung adenocarcinoma-to avoid histological bias and to reveal the true effect of smoking. Methods: A total of 2222 patients with lung adenocarcinoma confirmed by histological or cytological evidence were enrolled from January 1, 1999 to December 31, 2004. Differences in clinical features and prognosis between non-smoking and smoking patients were analyzed.Chisquare test was used for univariate comparisons. Univariate probability of survival was computed using Kaplan-Meier estimate and compared to using the log-rank test. Cox proportional hazards regression analysis was used to evaluate the risk of death. Results: There were 777 current smokers (34.96%), 197 former smokers (8.87%) and 1248 non-smoking patients (56.17%). 860 non-smoking patients (68.91%) were female, compared with 6.31% among current smokers and 4.06% among former smokers (p < 0.001). Non-smoking patients had an earlier age at diagnosis (p < 0.001) and a better response to chemotherapy (p < 0.001) compared to current smoking patients. Current smoking correlated with lower cell differentiation (p < 0.001) and worse prognosis (p = 0.0024). After multivariate analysis, smoking was identified as an independent negative prognostic factor (HR, 1.302;95% CI, 1.011 - 1.6780, p = 0.041). No difference in prognosis was observed according to smoking conditions in smoking patients. Conclusions: Significent differences exist in clinical features and prognosis between non-smoking and smoking lung adenocarcinoma patients. There is a strong evidence that non-smoking lung adenocarcinoma should be regard as different disease.

Extraordinary high-temperature mechanical properties in binder-free nanopolycrystalline WC ceramic

From the perspective of high-temperature applications,materials with excellent high-temperature mechanical properties are always desirable.The present work demonstrates that the binder-free nanopolycrystalline WC ceramic with an average grain size of 103 nm obtained by high-pressure and hightemperature sintering exhibits excellent mechanical properties at both room temperature and high temperature up to 1000℃.Specifically,the binder-free nanopolycrystalline WC ceramic still maintains a considerably high Vicker hardness H_(V)of 23.4 GPa at 1000℃,which is only 22%lower than the room temperature H_(V).This outstanding thermo-mechanical stability is superior to that of typical technical ceramics,e.g.SiC,Si_(3)N_(4),Al_(2)O_(3),etc.Nanocrystalline grains with many dislocations,numerous low-energy,highly stableΣ2 grain boundaries,and a relatively low thermal expansion coefficient,are responsible for the observed outstanding high-temperature mechanical properties.

Small onion-like BN leads to ultrafine-twinned cubic BN

Nanotwinned cubic boron nitride(nt-cBN) with remarkable hardness, toughness, and stability has attracted widespread attention due to its distinct scientific and industrial importance. The key for nt-cBN synthesis is to adopt an onion-like BN(oBN) nano-precursor and induce phase transition under high pressure. Here, we found that the size change of oBN used greatly affected the mechanical performance of products. With the precursor size decreasing from^320 to 90 nm, the Vickers hardness of nanostructured products improved from 61 to 108 GPa, due to the fact that large oBN nanoparticles possessed more flattened, orderly and graphite-like shell layers, in sharp contrast to the highly wrinkled and imperfect layers in small-diameter nanoparticles, thus resulting in the apparent reduction of ultrafinetwin substructure in the synthetic products. This study reveals that only small oBN precursor could produce complete ultrafine nt-cBN with outstanding performance. A practical route was proposed to further improve the performance of this important material.