LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)layered oxides have been regarded as promising alternative cathodes for the next generation of high-energy lithium ion batteries(LIBs)due to high discharge capacities and energy ...LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)layered oxides have been regarded as promising alternative cathodes for the next generation of high-energy lithium ion batteries(LIBs)due to high discharge capacities and energy densities at high operation voltage.However,the capacity fading under high operation voltage still restricts the practical application.Herein,the capacity degradation mechanism of NCM811 at atomic-scale is studied in detail under various cut-off voltages using aberration-corrected scanning transmission electron microscopy(STEM).It is observed that the crystal structure of NCM811 evolution from a layered structure to a rock-salt phase is directly accompanied by serious intergranular cracks under 4.9 V,which is distinguished from the generally accepted structure evolution of layered,disordered layered,defect rock salt and rock salt phases,also observed under 4.3 and 4.7 V.The electron energy loss spectroscopy analysis also confirms the reduction of Ni and Co from the surface to the bulk,not the previously reported only Li/Ni interlayer mixing.The degradation mechanism of NCM811 at a high cut-off voltage of4.9 V is attributed to the formation of intergranular cracks induced by defects,the direct formation of the rock salt phase,and the accompanied reduction of Ni^(2+)and Co^(2+)phases from the surface to the bulk.展开更多
MIL-101(Cr)is a promising moisture absorbent for solar-driven water harvesting from moisture to tackle the worldwide water shortage issue.However,the MIL-101(Cr)powder suffers from a long ab/desorption cycle due to th...MIL-101(Cr)is a promising moisture absorbent for solar-driven water harvesting from moisture to tackle the worldwide water shortage issue.However,the MIL-101(Cr)powder suffers from a long ab/desorption cycle due to the crystal aggregation caused by its inherent powder properties.Here,we demonstrate a MIL-101(Cr)nanofibrous composite membrane with a nanofibrous matrix where MIL-101(Cr)is monodisperse in the 3D porous nanofibrous matrix through a simple spray-electrospinning strategy.The continuous porous nanofibrous matrix not only offers sufficient sites for MIL-101(Cr)loading but also provides rapid moisture transport channels,resulting in a super-rapid ab/desorption duration of 50 min(including an absorption process for 40 min and a desorption process for 10 min)and multicycle daily water production of 15.9 L kg^(−1) d^(−1).Besides,the MIL-101(Cr)nanofibrous composite membrane establishes a high solar absorption of 92.8%,and excellent photothermal conversion with the surface temperature of 70.7°C under one-sun irradiation.In addition,the MIL-101(Cr)nanofibrous composite membrane shows excellent potential for practical application due to its flexibility,portability,and use stability.This work provides a new perspective of shortening MOF ab/desorption duration by introducing a porous nanofibrous matrix to improve the specific water production for the solar-driven ab/desorption water harvesting technique.展开更多
The degree of polymer chain orientation is a key structural parameter that determines the mechanical and physical properties of fibers.However,understanding and significantly tuning the orientation of fiber macromolec...The degree of polymer chain orientation is a key structural parameter that determines the mechanical and physical properties of fibers.However,understanding and significantly tuning the orientation of fiber macromolecular chains remain elusive.Herein,we propose a novel electrospinning technique that can efficiently modulate molecular chain orientation by controlling the electric field.In contrast to the typical electrospinning method,this technique can piecewise control the electric field by applying high voltage to the metal ring instead of the needle.Benefiting from this change,a new electric field distribution can be realized,leading to a non-monotonic change in the drafting force.As a result,the macromolecular chain orientation of polyethylene oxide(PEO)nanofibers was significantly improved with a recordhigh infrared dichroic ratio.This was further confirmed by the sharp decrease in the PEO jet fineness of approximately 80%and the nanofiber diameter from 298 to 114 nm.Interestingly,the crystallinity can also be adjusted,with an obvious drop from 74.9%to 31.7%,which is different from the high crystallinity caused by oriented chains in common materials.This work guides a new perspective for the preparation of advanced electrospun nanofibers with optimal orientation–crystallinity properties,a merited feature for various applications.展开更多
The Schrödinger equation for the 2S and 2P states of the lithium-like ions Z=5–7,9–10 is solved by using the Rayleigh-Ritz variational method in Hylleraas coordinates.The leading-order relativistic and QED corr...The Schrödinger equation for the 2S and 2P states of the lithium-like ions Z=5–7,9–10 is solved by using the Rayleigh-Ritz variational method in Hylleraas coordinates.The leading-order relativistic and QED corrections are calculated perturbatively and higher-order corrections are estimated.The transition frequencies between the 2S_(1/2)and 2P_(J)(J=1/2,3/2)states are determined and compared with experimental and other theoretical results.Specifically,isotope shifts are also calculated for B^(2+).展开更多
Bismuth vanadate(BiVO_(4))is an excellent photoanode material for photoelectrochemical(PEC)water splitting system,possessing high theoretical photoelectrocatalytic conversion efficiency.However,the actual PEC activity...Bismuth vanadate(BiVO_(4))is an excellent photoanode material for photoelectrochemical(PEC)water splitting system,possessing high theoretical photoelectrocatalytic conversion efficiency.However,the actual PEC activity and stability of BiVO_(4)are faced with great challenges due to factors such as severe charge recombination and slow water oxidation kinetics at the interface.Therefore,various interface regulation strategies have been adopted to optimize the BiVO_(4)photoanode.This review provides an in-depth analysis for the mechanism of interface regulation strategies from the perspective of factors affecting the PEC performance of BiVO_(4)photoanodes.These interface regulation strategies improve the PEC performance of BiVO_(4)photoanode by promoting charge separation and transfer,accelerating interfacial reaction kinetics,and enhancing stability.The research on the interface regulation strategies of BiVO_(4)photoanode is of great significance for promoting the development of PEC water splitting technology.At the same time,it also has inspiration for providing new ideas and methods for designing and preparing efficient and stable catalytic materials.展开更多
Objective:A prospective randomized control study investigated the feasibility and efficacy of adjuvant radiotherapy on patients with central hepatocellular carcinoma(HCC)after narrow-margin hepatectomy(<1 cm).This ...Objective:A prospective randomized control study investigated the feasibility and efficacy of adjuvant radiotherapy on patients with central hepatocellular carcinoma(HCC)after narrow-margin hepatectomy(<1 cm).This study presents an updated 10-year real-world evidence to further characterize the role of adjuvant radiotherapy.Methods:Patients with central HCC after narrow-margin hepatectomy(<1 cm)were prospectively assigned to adjuvant radiotherapy group and control group.Patients'outcome,adverse events,long-term recurrence and survival rates were investigated.Results:The 1-,5-,and 10-year recurrence-free survival(RFS)rates were 81.0%,43.9%,and 38.7%,respectively in adjuvant radiotherapy group and 71.7%,35.8%,and 24.2%,respectively in control group(log-rank test,P=0.09).The 1-,5-,and 10-year overall survival(OS)rates were 96.6%,54.7%,and 42.8%,respectively in adjuvant radiotherapy group and 90.2%,55.1%,and 30.0%,respectively in control group(log-rank test,P=0.20).The 1-,5-,and 10-year RFS rates for patients with small HCC(≤5 cm)were 91.1%,51.6%,and 48.4%,respectively in adjuvant radiotherapy group and 80.0%,36.6%,and 26.6%,respectively in control group(log-rank test,P=0.03).Landmark analysis demonstrated that patients with small HCC in adjuvant radiotherapy group had a significantly improved OS in second five years after treatment in comparison to patients in control group(log-rank test,P=0.05).Conclusions:Our updated results showed a sustained clinical benefit on reducing recurrence,improving longterm survival for small central HCC by adjuvant radiotherapy after narrow-margin hepatectomy.Long-term survival data also indicated that hepatectomy is an optimal treatment for selected patients with central HCC.展开更多
Objective: Hand-assisted laparoscopic liver resection has the advantages of open and laparoscopic surgeries.There is still lack of comparison of surgical outcomes between hand-assistied laparoscopic liver resection(HA...Objective: Hand-assisted laparoscopic liver resection has the advantages of open and laparoscopic surgeries.There is still lack of comparison of surgical outcomes between hand-assistied laparoscopic liver resection(HALLR)and open liver resection(OLR). This study compared the surgical outcomes of the two approaches between wellmatched patient cohorts.Methods: Patients who received liver resection during January 2014 and October 2017 in Cancer Hospital,Chinese Academy of Medical Sciences and Peking Union Medical College were included in this retrospective study. Propensity score matching(PSM) was performed to reduce selection bias between the two groups. Operation and short-term surgical outcomes were compared between the well matched groups.Results: During this period, 232 patients with a median age of 55.1 years old received OLR, while 49 patients with a median age of 54.7 years old received HALLR. Compared with HALLR group, OLR group has a higher proportion in male patients(190/232, 81.9% vs. 34/49, 69.4%, P=0.048) and lower albumin(43.2±4.5 vs. 44.8±3.7,P=0.020). After PSM, 49 patients from each group were included in the following analysis. Two groups were well balanced in their baseline characteristics, liver functions, preoperative treatments, abdominal surgery history, and surgical difficulty. None perioperative mortality was observed in both groups. Operation time and postoperative complications were similar in two groups(P=0.935, P=0.056). The HALLR group showed less bleeding amount(177.8±217.1 mL vs. 283.1±225.0 mL, P=0.003) and shorter postoperative stay period(6.9±2.2 d vs. 9.0±3.5 d,P=0.001).Conclusions: We demonstrated that hand-assisted laparoscopic surgery is feasible and safe for liver resection,including some difficult cases. HALLR can provide better bleeding control and faster recovery after surgery.展开更多
This study was designed to measure the pressure distribution of the intervertebral disc under different degrees of distraction of the interspinous process, because of a suspicion that the degree of distraction of the ...This study was designed to measure the pressure distribution of the intervertebral disc under different degrees of distraction of the interspinous process, because of a suspicion that the degree of distraction of the spinous process may have a close relationship with the disc load share. Six human cadaver lumbar spine L2-L5 segments were loaded in flexion, neutral position, and extension. The L3-L4 disc load was measured at each position using pressure measuring films. Shape-memory interspinous process implants (SMID) with different spacer heights, ranging in size from 10 to 20 mm at 2 mm increments, were used. It was found that a SMID with a spacer height equal to the distance of the interspinous process in the neutral position can share the biomechanical disc load without a significant change of load in the anterior annulus. An interspinous process stabilizing device (IPD) would not be appropriate to use in those cases with serious spinal stenosis because the over-distraction of the interspinous process by the SMID would lead to overloading the anterior annulus which is a recognized cause of disc degeneration.展开更多
In the present study,we reported our experience with partial aortic root remodeling for root reconstruction in patients with acute type A dissection,which involves in non-coronary sinus and/or the right coronary sinus...In the present study,we reported our experience with partial aortic root remodeling for root reconstruction in patients with acute type A dissection,which involves in non-coronary sinus and/or the right coronary sinus with just one trimmed Dacron graft.Between February 2001 and May 2010,we performed partial aortic root remodeling in 40 patients,who underwent emergency surgical intervention.The dissected sinuses were excised leaving a3-5 mm rim of the aortic wall from the attached aortic valve cusps.A short piece(4-5 cm) of collagen coated woven polyester vascular prosthesis was trimmed with one or two "tongues" to reconstruct the non-coronary sinus and/or the right coronary sinus,but without using separated patches.Additional procedures were including hemi-arch replacement in 11 patients,and total arch replacement plus stent-elephant trunk in 20 patients.The mean follow-up time was 36.4±3.6 months.In-hospital mortality was only 5.0%(2/40);furthermore,3(8.6%) patients underwent re-operation of the aortic valve and 2(5.7%) patients died during follow-up.At the end of follow-up,trivial or no aortic regurgitation was found in 33 patients,but mild aortic regurgitation was found in 2 patients.Our data suggest that the early and mid-term results of partial aortic root remodeling were favorable,and it restored valve durability and function.Thus,the use of technique for root reconstruction in patients with acute type A dissection should be vigorously encouraged.展开更多
Variations in the phenotypic characteristics of conifer needles is a consequence of genetic evolution that has been widely used in geographic variation and ecological studies.Although many studies are based on an in s...Variations in the phenotypic characteristics of conifer needles is a consequence of genetic evolution that has been widely used in geographic variation and ecological studies.Although many studies are based on an in situ sampling strategy and generally realize the contribution of environmental effects to variation in needle traits,it is still uncertain which needle traits are most influenced by genetic effects and which are most influenced by the environment.Using both a common garden experiment to eliminate environmental heterogeneity and an in situ sampling strategy,we compared 18 Pinus tabuliformis needle traits among 10 geographical populations.Using both sampling strategies,we found significant differences in needle traits among populations and among individuals within populations.Differences in the‘‘among-population’’variance component between the two sampling strategies revealed the environmental contribution among natural populations for each trait.The among-population variance in the following traits exceeded 8%:needle length,number of stomata within 2 mm(NS2),number of stomatal lines on the planar side,number of resin canals(RCN)and the resin canal area(RCA).For the stability of needle traits,NS2,RCN,RCA,ratio of the vascular bundle area to the RCA(VBA/RCA),and MA/RCA differed significantly in more than five provenance changes between the common garden populations and natural populations,which may be susceptible to environmental effects.Conversely,the crosssectional area,mesophyll area(MA),MA/(VBA+RCA),and MA/VBA were phenotypically stable.Geographic variation patterns and systematic relation of needle traits differed between the two sampling strategies,suggesting that in situ sampling results may reflect environmental effects and deviate statistical parameters for genetic study.Future studies of genetic evolution in the context of geographic variation should be based on appropriate sampling strategies and stable phenotypic traits.展开更多
Cardiac myxoma,the most common primary heart tumor,is located mainly in the left atrium.We reported a rare case of left ventricular myxoma incidentally found on echocardiography in an asymptomatic 60-year-old male.The...Cardiac myxoma,the most common primary heart tumor,is located mainly in the left atrium.We reported a rare case of left ventricular myxoma incidentally found on echocardiography in an asymptomatic 60-year-old male.The tumor was carefully resected without fragmentation.The patient had an uneventful recovery and was discharged home on the 4th postoperative day.Surgical resection of this type of cardiac myxoma is recommended due to the rarity of tumor location.展开更多
A two-way shape memory effect (TWSM E) in the Ti46.3Ni44.7Nb9 alloy has been systematically investigated by means of bending test and transmission electron microscopy (TEM ) observations. Based on the analysis of the ...A two-way shape memory effect (TWSM E) in the Ti46.3Ni44.7Nb9 alloy has been systematically investigated by means of bending test and transmission electron microscopy (TEM ) observations. Based on the analysis of the microstructure after training. the mechanism of TWSME in the Ti46.3 Ni44.7Nb9 alloy has been discussed.展开更多
Accurate and timely diagnosis of prosthetic joint infection is essential to initiate early treatment and achieve a favorable outcome.In this study,we used a rabbit model to assess the feasibility of technetium-99m-lab...Accurate and timely diagnosis of prosthetic joint infection is essential to initiate early treatment and achieve a favorable outcome.In this study,we used a rabbit model to assess the feasibility of technetium-99m-labeled annexin V for detecting prosthetic joint infection.Right knee arthroplasty was performed on 24 New Zealand rabbits.After surgery,methicillin-susceptible Staphylococcus aureus was intra-articularly injected to create a model of prosthetic joint infection(the infected group,n = 12).Rabbits in the control group were injected with sterile saline(n=12).Seven and 21 days after surgery,technetium-99m-labeled annexin V imaging was performed in 6 rabbits of each group.Images were acquired 1 and 4 hours after injection of technetium-99 mlabeled annexin V(150 MBq).The operated-to-normal-knee activity ratios were calculated for quantitative analysis.Seven days after surgery,increased technetium-99m-labeled annexin V uptake was observed in all cases.However,at 21 days a notable decrease was found in the control group,but not in the infected group.The operated-to-normal-knee activity ratios of the infected group were 1.84 ± 0.29 in the early phase and 2.19 ±0.34 in the delay phase,both of which were significantly higher than those of the control group(P=0.03 and P=0.02).The receiver operator characteristic curve analysis showed that the operated-to-normal-knee activity ratios of the delay phase at 21 days was the best indicator,with an accuracy of 80%.In conclusion,technetium-99m-labeled annexin V imaging could effectively distinguish an infected prosthetic joint from an uninfected prosthetic joint in a rabbit model.展开更多
The 660-km discontinuity that separates the Earth's upper and lower mantle has primarily been attributed to phase changes in olivine and other minerals.Resolving the sharpness is essential for predicting the compo...The 660-km discontinuity that separates the Earth's upper and lower mantle has primarily been attributed to phase changes in olivine and other minerals.Resolving the sharpness is essential for predicting the composition of the mantle and for understanding its dynamic effects.In this study,we used S-to-P conversions from the 660-km interface,termed S660P,arriving in the P-wave coda from one earthquake in the Izu–Bonin subduction zone recorded by stations in Alaska.The S660P signals were of high quality,providing us an unprecedented opportunity to resolve the sharpness of the discontinuity.Our study demonstrated,based on the impedance contrast given by the IASP91 model,that the discontinuity has a transitional thickness of^5 km.In addition,we observed a prominent arrival right after the S660P,which was best explained by S-to-P conversions from a deeper discontinuity at a depth of^720 km with a transitional thickness of^20 km,termed S720P.The 720-km discontinuity is most likely the result of a phase transition from majoritic garnet to perovskite in the segregated oceanic crust(mainly the mid-oceanic ridge basalt composition)at the uppermost lower mantle beneath this area.The inferred phase changes are also consistent with predictions from mineral physics experiments.展开更多
Corona discharge is a common phenomenon in power transmission lines external insulation, and it may cause serious defect if without effective detection. The ultraviolet (UV) imagery technology has been widely used to ...Corona discharge is a common phenomenon in power transmission lines external insulation, and it may cause serious defect if without effective detection. The ultraviolet (UV) imagery technology has been widely used to detect the corona discharge in industry in recent years, but some influence factors’ functions are not definite. In this paper, the fracture aluminum strands which is common in power transmission lines were used as the electrode model while a SuperB ultraviolet imager were utilized to detect, the photon count rate was detected with different detect distance, electric field, aluminum strands length and UV gain were applied. Then the multivariate regression analysis (MRA) was taken to calculate the function between the photon count and the factors.展开更多
Widely used in clinical research, the database is a new type of data management automation technology and the most efficient tool for data management. In this article, we first explain some basic concepts, such as the...Widely used in clinical research, the database is a new type of data management automation technology and the most efficient tool for data management. In this article, we first explain some basic concepts, such as the definition, classification, and establishment of databases. Afterward, the workflow for establishing databases, inputting data, verifying data, and managing databases is presented. Meanwhile, by discussing the application of databases in clinical research, we illuminate the important role of databases in clinical research practice. Lastly, we introduce the reanalysis of randomized controlled trials(RCTs) and cloud computing techniques, showing the most recent advancements of databases in clinical research.展开更多
Learning from the Internet is becoming more and more convenient and attracting more and more people. How to obtain knowledge from massive data and construct high quality knowledge graph has become a research hot topic...Learning from the Internet is becoming more and more convenient and attracting more and more people. How to obtain knowledge from massive data and construct high quality knowledge graph has become a research hot topic. This paper proposes a new method of knowledge graph construction based on crowd-sourcing. Firstly, learners build the subgraphs to acquire knowledge through the crowd-sourcing task; secondly, we put forward the fusion strategy of knowledge subgraph, in which knowledge graph is converted into the adjacency matrix, and the weight of the knowledge relation is calculated by matrix operations, thus knowledge graph is constructed. Finally, experiments conducted on an open platform show that the accuracy and integrity of proposed method of constructing knowledge graph are higher and our new method exists potential value for online learning and self-regulated learning.展开更多
With the rapid development of Internet of Things and miniaturized electronics, the demand for wearable power sources with high reliability and long duty cycle promotes the exploration of wearable thermoelectric genera...With the rapid development of Internet of Things and miniaturized electronics, the demand for wearable power sources with high reliability and long duty cycle promotes the exploration of wearable thermoelectric generators(TEGs). In particular, textile-based TEGs that can perpetually convert the ubiquitous temperature gradient between human body and ambience into electrical energy have attracted intensive attention to date.These lightweight and three-dimensional deformable TEGs comprised of fibers, filaments, yarns, or fabrics offer unique merits as wearable power source in comparison with conventional TEGs. In this review, we systematically summarize the state-of-the-art strategies for textile-based TEGs, including the structure design, fabrication, device performance, and application. Existing critical issues and future research emphasis are also discussed.展开更多
基金supported by the National Natural Science Foundation of China(U2032131)the Key R&D Program of Shaanxi Province(2021GY-118)the Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering(2022SX-TD012 and 2021SXTD012)。
文摘LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)layered oxides have been regarded as promising alternative cathodes for the next generation of high-energy lithium ion batteries(LIBs)due to high discharge capacities and energy densities at high operation voltage.However,the capacity fading under high operation voltage still restricts the practical application.Herein,the capacity degradation mechanism of NCM811 at atomic-scale is studied in detail under various cut-off voltages using aberration-corrected scanning transmission electron microscopy(STEM).It is observed that the crystal structure of NCM811 evolution from a layered structure to a rock-salt phase is directly accompanied by serious intergranular cracks under 4.9 V,which is distinguished from the generally accepted structure evolution of layered,disordered layered,defect rock salt and rock salt phases,also observed under 4.3 and 4.7 V.The electron energy loss spectroscopy analysis also confirms the reduction of Ni and Co from the surface to the bulk,not the previously reported only Li/Ni interlayer mixing.The degradation mechanism of NCM811 at a high cut-off voltage of4.9 V is attributed to the formation of intergranular cracks induced by defects,the direct formation of the rock salt phase,and the accompanied reduction of Ni^(2+)and Co^(2+)phases from the surface to the bulk.
基金This work was partly supported by the Funda-mental Research Funds for the Central Universi-ties (2232020D-15,2232020A-08,2232020G-01,2232020D-14,and 2232019D3-11)grants (51773037,51973027,51803023,52003044,and 61771123)from the National Natural Science Foundation of China+3 种基金This work has also been supported by the Chang Jiang Scholars Program and the Innovation Program of Shanghai Munici-pal Education Commission (2019-01-07-00-03-E00023)to Prof.Xiaohong Qinthe Shanghai Sailing Program (19YF1400700)the Opening Project of State Key Laboratory of High-Performance Ceramics and Superfine Microstruc-ture (SKL201906SIC)Young Elite Scientists Sponsorship Program by CAST and DHU Distin-guished Young Professor Program to Prof.Liming Wang.
文摘MIL-101(Cr)is a promising moisture absorbent for solar-driven water harvesting from moisture to tackle the worldwide water shortage issue.However,the MIL-101(Cr)powder suffers from a long ab/desorption cycle due to the crystal aggregation caused by its inherent powder properties.Here,we demonstrate a MIL-101(Cr)nanofibrous composite membrane with a nanofibrous matrix where MIL-101(Cr)is monodisperse in the 3D porous nanofibrous matrix through a simple spray-electrospinning strategy.The continuous porous nanofibrous matrix not only offers sufficient sites for MIL-101(Cr)loading but also provides rapid moisture transport channels,resulting in a super-rapid ab/desorption duration of 50 min(including an absorption process for 40 min and a desorption process for 10 min)and multicycle daily water production of 15.9 L kg^(−1) d^(−1).Besides,the MIL-101(Cr)nanofibrous composite membrane establishes a high solar absorption of 92.8%,and excellent photothermal conversion with the surface temperature of 70.7°C under one-sun irradiation.In addition,the MIL-101(Cr)nanofibrous composite membrane shows excellent potential for practical application due to its flexibility,portability,and use stability.This work provides a new perspective of shortening MOF ab/desorption duration by introducing a porous nanofibrous matrix to improve the specific water production for the solar-driven ab/desorption water harvesting technique.
基金partly supported by the grants(51973027 and 52003044)from the National Natural Science Foundation of Chinathe Fundamental Research Funds for the Central Universities(2232020A-08)+5 种基金International Cooperation Fund of Science and Technology Commission of Shanghai Municipality(21130750100)Major Scientific and Technological Innovation Projects of Shandong Province(2021CXGC011004)supported by the Chang Jiang Scholars Programthe Innovation Program of Shanghai Municipal Education Commission(2019-01-07-00-03-E00023)to Prof.Xiaohong QinYoung Elite Scientists Sponsorship Program by China Association for Science and Technology,State Key Laboratory for Modification of Chemical Fibers and Polymer Materials(KF2216)Donghua University Distinguished Young Professor Program to Prof.Liming Wang。
文摘The degree of polymer chain orientation is a key structural parameter that determines the mechanical and physical properties of fibers.However,understanding and significantly tuning the orientation of fiber macromolecular chains remain elusive.Herein,we propose a novel electrospinning technique that can efficiently modulate molecular chain orientation by controlling the electric field.In contrast to the typical electrospinning method,this technique can piecewise control the electric field by applying high voltage to the metal ring instead of the needle.Benefiting from this change,a new electric field distribution can be realized,leading to a non-monotonic change in the drafting force.As a result,the macromolecular chain orientation of polyethylene oxide(PEO)nanofibers was significantly improved with a recordhigh infrared dichroic ratio.This was further confirmed by the sharp decrease in the PEO jet fineness of approximately 80%and the nanofiber diameter from 298 to 114 nm.Interestingly,the crystallinity can also be adjusted,with an obvious drop from 74.9%to 31.7%,which is different from the high crystallinity caused by oriented chains in common materials.This work guides a new perspective for the preparation of advanced electrospun nanofibers with optimal orientation–crystallinity properties,a merited feature for various applications.
基金Project supported by the National Natural Science Foundation of China (Grant No. 11774080)supported by NSERC of Canada
文摘The Schrödinger equation for the 2S and 2P states of the lithium-like ions Z=5–7,9–10 is solved by using the Rayleigh-Ritz variational method in Hylleraas coordinates.The leading-order relativistic and QED corrections are calculated perturbatively and higher-order corrections are estimated.The transition frequencies between the 2S_(1/2)and 2P_(J)(J=1/2,3/2)states are determined and compared with experimental and other theoretical results.Specifically,isotope shifts are also calculated for B^(2+).
基金supported by the National Natural Science Foundation of China(52202261)Outstanding Youth Foundation of Shandong Province,China(ZR2019JQ 14)Taishan Scholar Young Talent Program(tsqn201909114).
文摘Bismuth vanadate(BiVO_(4))is an excellent photoanode material for photoelectrochemical(PEC)water splitting system,possessing high theoretical photoelectrocatalytic conversion efficiency.However,the actual PEC activity and stability of BiVO_(4)are faced with great challenges due to factors such as severe charge recombination and slow water oxidation kinetics at the interface.Therefore,various interface regulation strategies have been adopted to optimize the BiVO_(4)photoanode.This review provides an in-depth analysis for the mechanism of interface regulation strategies from the perspective of factors affecting the PEC performance of BiVO_(4)photoanodes.These interface regulation strategies improve the PEC performance of BiVO_(4)photoanode by promoting charge separation and transfer,accelerating interfacial reaction kinetics,and enhancing stability.The research on the interface regulation strategies of BiVO_(4)photoanode is of great significance for promoting the development of PEC water splitting technology.At the same time,it also has inspiration for providing new ideas and methods for designing and preparing efficient and stable catalytic materials.
基金supported by the CAMS Innovation Fund for Medical Science(CIFMS)(CAMS-2016-I2M-3-025)。
文摘Objective:A prospective randomized control study investigated the feasibility and efficacy of adjuvant radiotherapy on patients with central hepatocellular carcinoma(HCC)after narrow-margin hepatectomy(<1 cm).This study presents an updated 10-year real-world evidence to further characterize the role of adjuvant radiotherapy.Methods:Patients with central HCC after narrow-margin hepatectomy(<1 cm)were prospectively assigned to adjuvant radiotherapy group and control group.Patients'outcome,adverse events,long-term recurrence and survival rates were investigated.Results:The 1-,5-,and 10-year recurrence-free survival(RFS)rates were 81.0%,43.9%,and 38.7%,respectively in adjuvant radiotherapy group and 71.7%,35.8%,and 24.2%,respectively in control group(log-rank test,P=0.09).The 1-,5-,and 10-year overall survival(OS)rates were 96.6%,54.7%,and 42.8%,respectively in adjuvant radiotherapy group and 90.2%,55.1%,and 30.0%,respectively in control group(log-rank test,P=0.20).The 1-,5-,and 10-year RFS rates for patients with small HCC(≤5 cm)were 91.1%,51.6%,and 48.4%,respectively in adjuvant radiotherapy group and 80.0%,36.6%,and 26.6%,respectively in control group(log-rank test,P=0.03).Landmark analysis demonstrated that patients with small HCC in adjuvant radiotherapy group had a significantly improved OS in second five years after treatment in comparison to patients in control group(log-rank test,P=0.05).Conclusions:Our updated results showed a sustained clinical benefit on reducing recurrence,improving longterm survival for small central HCC by adjuvant radiotherapy after narrow-margin hepatectomy.Long-term survival data also indicated that hepatectomy is an optimal treatment for selected patients with central HCC.
基金supported by PUMC Youth Fund/ Fundamental Research Funds for the Central Universities (No. 3332016031)National Key Research and Development Plan (No. 2016YFD0400604-03)
文摘Objective: Hand-assisted laparoscopic liver resection has the advantages of open and laparoscopic surgeries.There is still lack of comparison of surgical outcomes between hand-assistied laparoscopic liver resection(HALLR)and open liver resection(OLR). This study compared the surgical outcomes of the two approaches between wellmatched patient cohorts.Methods: Patients who received liver resection during January 2014 and October 2017 in Cancer Hospital,Chinese Academy of Medical Sciences and Peking Union Medical College were included in this retrospective study. Propensity score matching(PSM) was performed to reduce selection bias between the two groups. Operation and short-term surgical outcomes were compared between the well matched groups.Results: During this period, 232 patients with a median age of 55.1 years old received OLR, while 49 patients with a median age of 54.7 years old received HALLR. Compared with HALLR group, OLR group has a higher proportion in male patients(190/232, 81.9% vs. 34/49, 69.4%, P=0.048) and lower albumin(43.2±4.5 vs. 44.8±3.7,P=0.020). After PSM, 49 patients from each group were included in the following analysis. Two groups were well balanced in their baseline characteristics, liver functions, preoperative treatments, abdominal surgery history, and surgical difficulty. None perioperative mortality was observed in both groups. Operation time and postoperative complications were similar in two groups(P=0.935, P=0.056). The HALLR group showed less bleeding amount(177.8±217.1 mL vs. 283.1±225.0 mL, P=0.003) and shorter postoperative stay period(6.9±2.2 d vs. 9.0±3.5 d,P=0.001).Conclusions: We demonstrated that hand-assisted laparoscopic surgery is feasible and safe for liver resection,including some difficult cases. HALLR can provide better bleeding control and faster recovery after surgery.
基金supported by the Medical Key Technology Development Program,Nanjing Health Bureau (ZKK08010)
文摘This study was designed to measure the pressure distribution of the intervertebral disc under different degrees of distraction of the interspinous process, because of a suspicion that the degree of distraction of the spinous process may have a close relationship with the disc load share. Six human cadaver lumbar spine L2-L5 segments were loaded in flexion, neutral position, and extension. The L3-L4 disc load was measured at each position using pressure measuring films. Shape-memory interspinous process implants (SMID) with different spacer heights, ranging in size from 10 to 20 mm at 2 mm increments, were used. It was found that a SMID with a spacer height equal to the distance of the interspinous process in the neutral position can share the biomechanical disc load without a significant change of load in the anterior annulus. An interspinous process stabilizing device (IPD) would not be appropriate to use in those cases with serious spinal stenosis because the over-distraction of the interspinous process by the SMID would lead to overloading the anterior annulus which is a recognized cause of disc degeneration.
文摘In the present study,we reported our experience with partial aortic root remodeling for root reconstruction in patients with acute type A dissection,which involves in non-coronary sinus and/or the right coronary sinus with just one trimmed Dacron graft.Between February 2001 and May 2010,we performed partial aortic root remodeling in 40 patients,who underwent emergency surgical intervention.The dissected sinuses were excised leaving a3-5 mm rim of the aortic wall from the attached aortic valve cusps.A short piece(4-5 cm) of collagen coated woven polyester vascular prosthesis was trimmed with one or two "tongues" to reconstruct the non-coronary sinus and/or the right coronary sinus,but without using separated patches.Additional procedures were including hemi-arch replacement in 11 patients,and total arch replacement plus stent-elephant trunk in 20 patients.The mean follow-up time was 36.4±3.6 months.In-hospital mortality was only 5.0%(2/40);furthermore,3(8.6%) patients underwent re-operation of the aortic valve and 2(5.7%) patients died during follow-up.At the end of follow-up,trivial or no aortic regurgitation was found in 33 patients,but mild aortic regurgitation was found in 2 patients.Our data suggest that the early and mid-term results of partial aortic root remodeling were favorable,and it restored valve durability and function.Thus,the use of technique for root reconstruction in patients with acute type A dissection should be vigorously encouraged.
基金funded by the Fundamental Research Funds for the Central Universities(2015ZCQ-SW-02)
文摘Variations in the phenotypic characteristics of conifer needles is a consequence of genetic evolution that has been widely used in geographic variation and ecological studies.Although many studies are based on an in situ sampling strategy and generally realize the contribution of environmental effects to variation in needle traits,it is still uncertain which needle traits are most influenced by genetic effects and which are most influenced by the environment.Using both a common garden experiment to eliminate environmental heterogeneity and an in situ sampling strategy,we compared 18 Pinus tabuliformis needle traits among 10 geographical populations.Using both sampling strategies,we found significant differences in needle traits among populations and among individuals within populations.Differences in the‘‘among-population’’variance component between the two sampling strategies revealed the environmental contribution among natural populations for each trait.The among-population variance in the following traits exceeded 8%:needle length,number of stomata within 2 mm(NS2),number of stomatal lines on the planar side,number of resin canals(RCN)and the resin canal area(RCA).For the stability of needle traits,NS2,RCN,RCA,ratio of the vascular bundle area to the RCA(VBA/RCA),and MA/RCA differed significantly in more than five provenance changes between the common garden populations and natural populations,which may be susceptible to environmental effects.Conversely,the crosssectional area,mesophyll area(MA),MA/(VBA+RCA),and MA/VBA were phenotypically stable.Geographic variation patterns and systematic relation of needle traits differed between the two sampling strategies,suggesting that in situ sampling results may reflect environmental effects and deviate statistical parameters for genetic study.Future studies of genetic evolution in the context of geographic variation should be based on appropriate sampling strategies and stable phenotypic traits.
文摘Cardiac myxoma,the most common primary heart tumor,is located mainly in the left atrium.We reported a rare case of left ventricular myxoma incidentally found on echocardiography in an asymptomatic 60-year-old male.The tumor was carefully resected without fragmentation.The patient had an uneventful recovery and was discharged home on the 4th postoperative day.Surgical resection of this type of cardiac myxoma is recommended due to the rarity of tumor location.
文摘A two-way shape memory effect (TWSM E) in the Ti46.3Ni44.7Nb9 alloy has been systematically investigated by means of bending test and transmission electron microscopy (TEM ) observations. Based on the analysis of the microstructure after training. the mechanism of TWSME in the Ti46.3 Ni44.7Nb9 alloy has been discussed.
基金supported by the Chinese National Nature Sciences Foundation(31070861,81171745)
文摘Accurate and timely diagnosis of prosthetic joint infection is essential to initiate early treatment and achieve a favorable outcome.In this study,we used a rabbit model to assess the feasibility of technetium-99m-labeled annexin V for detecting prosthetic joint infection.Right knee arthroplasty was performed on 24 New Zealand rabbits.After surgery,methicillin-susceptible Staphylococcus aureus was intra-articularly injected to create a model of prosthetic joint infection(the infected group,n = 12).Rabbits in the control group were injected with sterile saline(n=12).Seven and 21 days after surgery,technetium-99m-labeled annexin V imaging was performed in 6 rabbits of each group.Images were acquired 1 and 4 hours after injection of technetium-99 mlabeled annexin V(150 MBq).The operated-to-normal-knee activity ratios were calculated for quantitative analysis.Seven days after surgery,increased technetium-99m-labeled annexin V uptake was observed in all cases.However,at 21 days a notable decrease was found in the control group,but not in the infected group.The operated-to-normal-knee activity ratios of the infected group were 1.84 ± 0.29 in the early phase and 2.19 ±0.34 in the delay phase,both of which were significantly higher than those of the control group(P=0.03 and P=0.02).The receiver operator characteristic curve analysis showed that the operated-to-normal-knee activity ratios of the delay phase at 21 days was the best indicator,with an accuracy of 80%.In conclusion,technetium-99m-labeled annexin V imaging could effectively distinguish an infected prosthetic joint from an uninfected prosthetic joint in a rabbit model.
基金We are grateful for the thoughtful and constructive comments provided by two anonymous reviewers and the editor(Dr.Wei Leng).We also thank Jinfeng Hu for his contributions to this work at an early stage.Seismic data from the USArray network were accessed via the Data Management Center(DMC)of the Incorporated Research Institutions for Seismology(IRIS).Some figures were prepared using Generic Mapping Tools(GMT,Wessel and Smith,1999)GNUPLOT.This work was funded by the National Natural Science Foundation of China(grant no.91858205).
文摘The 660-km discontinuity that separates the Earth's upper and lower mantle has primarily been attributed to phase changes in olivine and other minerals.Resolving the sharpness is essential for predicting the composition of the mantle and for understanding its dynamic effects.In this study,we used S-to-P conversions from the 660-km interface,termed S660P,arriving in the P-wave coda from one earthquake in the Izu–Bonin subduction zone recorded by stations in Alaska.The S660P signals were of high quality,providing us an unprecedented opportunity to resolve the sharpness of the discontinuity.Our study demonstrated,based on the impedance contrast given by the IASP91 model,that the discontinuity has a transitional thickness of^5 km.In addition,we observed a prominent arrival right after the S660P,which was best explained by S-to-P conversions from a deeper discontinuity at a depth of^720 km with a transitional thickness of^20 km,termed S720P.The 720-km discontinuity is most likely the result of a phase transition from majoritic garnet to perovskite in the segregated oceanic crust(mainly the mid-oceanic ridge basalt composition)at the uppermost lower mantle beneath this area.The inferred phase changes are also consistent with predictions from mineral physics experiments.
文摘Corona discharge is a common phenomenon in power transmission lines external insulation, and it may cause serious defect if without effective detection. The ultraviolet (UV) imagery technology has been widely used to detect the corona discharge in industry in recent years, but some influence factors’ functions are not definite. In this paper, the fracture aluminum strands which is common in power transmission lines were used as the electrode model while a SuperB ultraviolet imager were utilized to detect, the photon count rate was detected with different detect distance, electric field, aluminum strands length and UV gain were applied. Then the multivariate regression analysis (MRA) was taken to calculate the function between the photon count and the factors.
基金supported by Fundamental Research Funds of State Key Laboratory of Ophthalmology (Grant No.2015QN01)Young Teacher Top-Support project of Sun Yat-sen University(Grant No.2015ykzd11)+4 种基金the Cultivation Projects for Young Teaching Staff of Sun Yat-sen University(Grant No.12ykpy61) from the Fundamental Research Funds for the Central Universitiesthe Pearl River Science and Technology New Star(Grant No.2014J2200060)Project of Guangzhou City,the Guangdong Provincial Natural Science Foundation for Distinguished Young Scholars of China(Grant No. 2014A030306030)Youth Science and Technology Innovation Talents Funds in Special Support Plan for High Level Talents in Guangdong Province(Grant No. 2014TQ01R573)Key Research Plan for National Natural Science Foundation of China in Cultivation Project (No.91546101)
文摘Widely used in clinical research, the database is a new type of data management automation technology and the most efficient tool for data management. In this article, we first explain some basic concepts, such as the definition, classification, and establishment of databases. Afterward, the workflow for establishing databases, inputting data, verifying data, and managing databases is presented. Meanwhile, by discussing the application of databases in clinical research, we illuminate the important role of databases in clinical research practice. Lastly, we introduce the reanalysis of randomized controlled trials(RCTs) and cloud computing techniques, showing the most recent advancements of databases in clinical research.
基金supported by National Social Science Foundation project (17BXW065)Science and Technology Research project of Henan (14430051007)+1 种基金Reform Research Project of Higher Education of Henan (2014SJGLX007)Science and Technology Research project of Zhengzhou(141PPTGG368)
文摘Learning from the Internet is becoming more and more convenient and attracting more and more people. How to obtain knowledge from massive data and construct high quality knowledge graph has become a research hot topic. This paper proposes a new method of knowledge graph construction based on crowd-sourcing. Firstly, learners build the subgraphs to acquire knowledge through the crowd-sourcing task; secondly, we put forward the fusion strategy of knowledge subgraph, in which knowledge graph is converted into the adjacency matrix, and the weight of the knowledge relation is calculated by matrix operations, thus knowledge graph is constructed. Finally, experiments conducted on an open platform show that the accuracy and integrity of proposed method of constructing knowledge graph are higher and our new method exists potential value for online learning and self-regulated learning.
基金financial support from the Fundamental Research Funds for the Central Universities(2232019A3-05 and 2232019D3-11)the National Natural Science Foundation of China(No.51603036)+2 种基金Young Elite Scientists Sponsorship Program by CAST(2017QNRC001)Shanghai Sailing Program(19YF1400700)DHU Distinguished Young Professor Program
文摘With the rapid development of Internet of Things and miniaturized electronics, the demand for wearable power sources with high reliability and long duty cycle promotes the exploration of wearable thermoelectric generators(TEGs). In particular, textile-based TEGs that can perpetually convert the ubiquitous temperature gradient between human body and ambience into electrical energy have attracted intensive attention to date.These lightweight and three-dimensional deformable TEGs comprised of fibers, filaments, yarns, or fabrics offer unique merits as wearable power source in comparison with conventional TEGs. In this review, we systematically summarize the state-of-the-art strategies for textile-based TEGs, including the structure design, fabrication, device performance, and application. Existing critical issues and future research emphasis are also discussed.
