Risk factors and managements of hemorrhage associated with pancreatic fistula after pancreaticoduodenectomy

BACKGROUND: Post-pancreaticoduodenectomy pancreatic fistula associated hemorrhage (PPFH) is one of the leading lethal complications. Our study was to analyze the risk factors and managements of hemorrhage associated with pancreatic fistula after pancreaticoduodenectomy, and to evaluate treatment options. METHOD: We analyzed 445 patients who underwent pancreaticoduodenectomy or pylorus-preserving pancreaticoduodenectomy and evaluated the relevance between clinical data and PPFH. RESULTS: The incidence of postoperative pancreatic fistula (POPF) was 27.42% (122/445), and the incidence of PPFH was 4.49% (20/445). Among the 20 patients with PPFH, 7 died and 13 were cured. Interventional angiographic therapy was performed for 10 patients and 5 were successfully treated. Relaparotomy was performed for 5 patients and 2 were successfully cured. Univariate logistic regression analysis indicated that several risk factors were related to PPFH: the nature of tumor (carcinoid/low-grade or high-grade malignancy), preoperative day 1. serum prealbumin, preoperative day 1 total bilirubin (TBIL), operative time, blood loss in the operation, operative method (vascular resection and revascularization), postoperative day 3 TBIL, biliary fistula, and the grade of POPF. The multivariate stepwise logistic regression analysis demonstrated that the nature of tumor and the grade of POPF were independently risk factors of PPFH. Receiver operating characteristic curve indicated that preoperative day 1 serum prealbumin level <173 mg/L and postoperative day 3 TBIL level.1.68.tmol/L were the risk factors of PPFH. CONCLUSIONS; The risk of PPFH was found to be increased with high potential malignancy and high grade of POPE Angiography-embolization is one of the major and effective therapies for PPFH. Extraluminal-intraluminal PPFH is more serious and needs more aggressive treatments.

Intracellular redox potential-driven live-cell synthesis of CdSe quantum dots in Staphylococcus aureus

Biosynthesized semiconductor quantum dots(QDs) have bright fluorescence,adjustable particle sizes,and environmental friendliness,endowing them with convenience and potential for biological applications.Due to the unclear mechanism of the cellular environment on the live-cell synthesis of QDs,it is still difficult to regulate their optical properties.Here,the critical role of the intracellular redox environment in regulating the fluorescence properties of biosynthesized CdSe QDs in Staphylococcus aureus(S.aureus) has been elucidated.The glutathione peroxidase(GPx) activity directly affects the intracellular H_(2)O_(2) produced in the SeO_(3)^(2-) reduction,which further manipulates the glutathione redox cycle to determine the content of low-valence Seintermediates.As a result,the fluorescence intensity of the synthesized CdSe QDs increases by 60% in the GPx overexpressed cells.The cellular redox potential that is controlled by the GSH redox cycle provides the driving force for the reduction of SeO_(3)^(2-),facilitating the synthesis of CdSe QDs in S.aureus cells.The proposed mechanism of the cellular redox state provides a new perspective for regulating the synthesis of semiconductor nanomaterials in live cells.

A robust and unique approach for tuning the energy level of Ag_(2)Se quantum dots via“on-surface”manipulation of nitrogencontaining groups of surface-coordinated ligands

Effects of surface chemistry on energy levels or optical properties of semiconductor nanocrystals have attracted considerable attention and show great promise in broad applications.Yet,it remains challenging to controllably tune the photoluminescence(PL)of quantum dots(QDs)by manipulating surface ligands.Herein,we investigated effects of the ligand,glutathione(GSH),on PL properties of near-infrared(NIR)Ag_(2)Se QDs by“on-surface”manipulation,that is,precisely manipulating the chelating group without dissociating the ligand from the surface.The anchoring of the amino group was found to be controlled by solution pH,whereas the binding of the thiol group to the Ag+was pH independent,maintaining the“on-surface”state of GSH.By tuning the pH-controlled binding of amino groups,the energy level or the bandgap of Ag2Se QDs could be increased by up to 140 meV.The increased bandgap resulted in the blueshift of PL spectrum,which could be reversibly tuned by up to 75 nm.The pH-mediated tunable PL properties of QDs could also be extended to other nitrogen-containing pH-sensitive groups which could coordinate to the Ag+,not limited to the amino group.Our work would facilitate the study of nanocrystal surface chemistry and our model that the binding of amino groups affected energy levels of Ag2Se QDs might facilitate new insights into the electronic structure and energy level of other QD-ligand complexes.

Diffusion effect on the decay of time-resolved photoluminescence under low illumination in lead halide perovskites

Time-resolved photoluminescence(TRPL)has been extensively used to measure the carrier lifetime in lead halide perovskites.The TRPL curves of perovskite materials are usually fitted with a multi-exponential function,instead of a single exponential one.This was considered to be a result of the surface and the bulk recombination or the additional radiative recombination caused by the high excited carrier density.Here,a new model considering the diffusion and the trap-assisted recombination of carriers is proposed to explain the TRPL curves.The expressions of the TRPL curves and the transient absorption(TA)dynamic curves are theoretically derived,demonstrating that the TRPL curve is an infinite exponential series,regardless of the presence of surface recombination or not.Our newly developed highly sensitive nanosecond TA and TRPL were employed to measure the carrier dynamics of the same sample under low illumination in the linear response region of TA,thereby experimentally verifying our model.These results suggest that the decay of the TRPL is not only a consequence of the carrier recombination but also the carrier diffusion.TRPL cannot provide a direct measurement of the carrier lifetime,whereas TA spectroscopy can.Furthermore,the surface and the bulk recombination can be resolved and the average diffusion coefficient(D)can also be correctly obtained by combining TRPL and TA measurements.We also propose an approximate method for calculating the carrier lifetime and diffusion coefficient of high-quality perovskite films.Our model provides not only a new interpretation of the dynamics of the PL decay but also a deep insight into the carrier dynamics in the nanosecond time scale under working condition of perovskites solar cells.

近红外量子点分析性能调控

近红外量子点因其吸收光谱更宽、荧光发射波长更长等特性,具有广阔的应用前景.优异的分析性能是实现其应用的基础,而分析性能,包括荧光发射波长、荧光强度及表面性质等,与其结构息息相关.基于对其结构的深入研究,近红外量子点分析性能的精细调控得以实现.基于本课题组的工作,本文从无机晶核与表面配体层两方面出发,评述了近年来近红外量子点分析性能的调控策略,指出了目前存在的不足与挑战,以期推动近红外量子点的应用与发展.

单病毒示踪

病毒是对人类健康威胁最大的病原之一,由其引发的病毒性疾病对人民健康、国家安全和社会经济构成重大威胁。病毒感染机制研究对病毒性疾病的防控及治疗具有重大意义。病毒侵染宿主细胞的动态过程涉及病毒组分与多种细胞组分或细胞器间复杂的相互作用,但是传统手段无法对该动态过程进行实时跟踪研究。单病毒示踪技术作为一种可以实时原位示踪单颗病毒侵染过程的技术,在病毒感染机制研究方面起着愈来愈重要的作用。借助于该技术,能够获取病毒侵染过程中病毒入胞途径、胞内转运过程、病毒核酸释放及其与细胞间的相互作用等动态过程信息,从而对病毒的感染机制进行分子水平的深入研究。本文就单病毒示踪技术所涉及的测量技术、标记技术和信息获取进行阐述,总结归纳了单病毒示踪在病毒感染机制研究中的最新进展,并探讨了该技术目前存在的挑战性问题以及未来发展的方向。

A review of feature fusion-based media popularity prediction methods

With the popularization of social media,the way of information transmission has changed,and the prediction of information popularity based on social media platforms has attracted extensive attention.Feature fusion-based media popularity prediction methods focus on the multi-modal features of social media,which aim at exploring the key factors affecting media popularity.Meanwhile,the methods make up for the deficiency in feature utilization of traditional methods based on information propagation processes.In this paper,we review feature fusion-based media popularity prediction methods from the perspective of feature extraction and predictive model construction.Before that,we analyze the influencing factors of media popularity to provide intuitive understanding.We further argue about the advantages and disadvantages of existing methods and datasets to highlight the future directions.Finally,we discuss the applications of popularity prediction.To the best of our knowledge,this is the first survey reporting feature fusion-based media popularity prediction methods.