Two-dimensional materials provide extraordinary opportunities for exploring phenomena arising in atomically thin crystals. Beginning with the first isolation of graphene, mechanical exfoliation has ...been a key to provide high-quality two-dimensional materials, but despite improvements it is still limited in yield, lateral size and contamination. Here we introduce a contamination-free, one-step and universal Au-assisted mechanical exfoliation method and demonstrate its effectiveness by isolating 40 types of single-crystalline monolayers, including elemental two-dimensional crystals, metal-dichalcogenides, magnets and superconductors. Most of them are of millimeter-size and high-quality, as shown by transfer-free measurements of electron microscopy, photo spectroscopies and electrical transport. Large suspended two-dimensional crystals and heterojunctions were also prepared with high-yield. Enhanced adhesion between the crystals and the substrates enables such efficient exfoliation, for which we identify a gold-assisted exfoliation method that underpins a universal route for producing large-area monolayers and thus supports studies of fundamental properties and potential application of two-dimensional materials.
Background
There lacks an ideal model for accurately predicting clinically relevant postoperative pancreatic fistula (CR-POPF) after pancreatoduodenectomy (PD). This study aimed at developing a ...nomogram with high accuracy in predicting CR-POPF after PD.
Methods
A total of 1182 patients undergoing PD in the First Affiliated Hospital of Sun Yat-sen University (FAHSYSU,
n
= 762) and Fudan University Shanghai Cancer Center (FUSCC,
n
= 420) between January 2010 and May 2018 were enrolled. The patients from FAHSYSU were assigned as testing cohort, and those from FUSCC were used as external validation cohort. Univariate and multivariate logistic regression analyses were performed to determine the predictive factors for CR-POPF. Nomogram was developed on the basis of significant predictors. The performance of nomogram was evaluated by area under receiver operating characteristic (ROC) curve (AUC), calibration curve, and decision curve analysis.
Results
In testing cohort, 87 out of 762 patients developed CR-POPF. Three predictors were significantly associated with CR-POPF, including body mass index ≥24.0 kg/m
2
, pancreatic duct diameter <3 mm, and drainage fluid amylase on postoperative day 1 ≥2484 units/L (all
p
≤ 0.001). Prediction of nomogram was accurate with AUC of 0.934 (95% confidence interval CI: 0.914–0.950) in testing cohort and 0.744 (95% CI: 0.699–0.785) in external validation cohort. The predictive accuracy of nomogram was better than that of previously proposed fistula risk scores both in testing and external validation cohort (all
p
< 0.05).
Conclusions
The novel nomogram based on three easily available parameters could accurately predict CR-POPF after PD. It would have high clinical value due to its accuracy and convenience.
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EMUNI, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The microstructures and micro-hardness of a solution-treated Sr-modified Al-Si-Mg alloy are investigated. The dimension and shape factor of eutectic Si particles, as well as the mean diameter and ...fraction of Si-containing dispersoids, are quantitatively measured. It is revealed that the best spheroidized and refined eutectic Si particles can be obtained when the solution time is about 2 h. With further raising the solution time, the eutectic Si particle grows up anisotropically and exhibits facet characteristics with sharp edges. Meanwhile, some coarsened particles appear by mutual overlapping. Moreover, the Si-rich phases in α-Al matrix facilitate the precipitation of Si-containing dispersoids. The enhanced precipitation of Si-containing dispersoids with raising solution time leads to the formation of dispersoids free zones (DFZs) between two adjoint Si-containing dispersoids regions or in the areas adjacent to eutectics. Additionally, the solution strengthening effect of Mg atoms is stronger than that of Si atoms, which contributes to the increased micro-hardness of α-Al matrix in the initial solution stage. The dispersion strengthening effect of Si-containing dispersoids first increases then remains almost unchanged, revealing the change rule of micro-hardness in α-Al matrix during the later solution treatment. Furthermore, the lower micro-hardness of (Al+Si) eutectics is strongly related with the smaller eutectic Si particles.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
High-temperature compressive experiments of a Ni-based superalloy containing δ phase (Ni3Nb) are conducted. The dynamic dissolution behavior of δ phase in hot deformation process is quantitatively ...investigated. The dissolution mechanisms of δ phase are analyzed by Transmission Electron Microscopy (TEM) and first-principles calculations. Results reveal that the dissolution of δ phase is accelerated with increasing deformation temperature or deformation degree. But, the dissolution of δ phase becomes weaken as the strain rate is raised. The shear modulus (G) and bulk modulus (B) of δ phase decrease with increasing temperature or reducing pressure. The positive Cauchy pressure (C12–C44) and the larger ratio of B/G (greater than 1.75) reveal that δ phase is ductile at high temperatures or pressures. The intense interactions between dislocations and δ phase induce the stress concentration and the rapid diffusion of Nb atoms, which accelerate the precipitation/dissolution of δ phase. A phenomenological model is established for depicting the dissolution behavior of δ phase in hot deformation process. The measured results are identical with the forecasted ones, which demonstrates the established model is feasible to accurately depict the dynamic dissolution behaviors of δ phase in hot deformation process.
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•High-temperature compressive experiments of a Ni-based superalloy containing δ phase (Ni3Nb) are conduct.•The dissolution of δ phase is accelerated with increasing deformation temperature or true strain.•Local stress concentration induced by the interactions between dislocation and δ phases twists δ phases.•The dislocation-assisted Nb atoms diffusion play a major role for the dissolution of δ phases.•The developed model is feasible to predict the dissolution behaviors of δ phases during hot deformation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Mo–TiC–La2O3 molybdenum alloys were strengthened and toughened by the synergistic action of nano-carbide particles and rare earth oxides. In this paper, the Mo–TiC–La2O3 alloy system was prepared by ...powder metallurgy. The microstructure was characterized by optical, scanning, and transmission electron microscopy. The mechanical properties were tested using the hardness tester and universal tensile testing machine. The grain size of the Mo–TiC–La2O3 alloy is smaller than the Mo–TiC and Mo–La2O3 alloys. The strength and elongation of annealed Mo–TiC–La2O3 alloy are 1291 MPa and 6.6%, respectively. The strength and ductility of the annealed Mo–TiC–La2O3 alloy are higher than the Mo–TiC and Mo–La2O3 alloys. According to the interfacial mismatch between the secondary phases and the matrix, along with oxygen impurities interactions, the mechanisms of strengthening and toughening of the secondary phases in the Mo–TiC–La2O3 alloy were revealed.
•The strength of alloys increases from Mo–La2O3 to Mo–TiC, to Mo–TiC–La2O3.•Mo–TiC–La2O3 alloy not only has a high hardness, the high tensile strength, but also 6.59% elongation.•Mo–TiC–La2O3 alloy strengthening from nano-TiC, TiO2, and La2Ti2O7 phases and toughening from La2O3.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
DNA intercalation has increasingly been studied for various scenario implementations due to the diverse functions of DNA/intercalators. Nascent organic photoelectrochemical transistor (OPECT) ...biosensing taking place in organic electronics and photoelectrochemical bioanalysis represents a promising technological frontier in the arena. In this work, we first devise DNA intercalation-enabled OPECT for miRNA detection with a superior gain up to 17100. Intercalation of Ru(bpy)2dppz2+ within the miRNA-initiated hybrid chain reaction (HCR)-derived duplex DNA is realized for producing anodic photocurrent upon light stimulation, causing the corresponding target-dependent alternation in gate voltage (VG) and hence the modulated channel current (IDS) of poly (3,4-ethylenedioxythiophene) doped with poly (styrene sulfonate) (PEDOT:PSS) under specific drain voltage (VDS) for quantitative miRNA-21 analysis, which shows a wide linear relationship and a low detection limit of 5.5 × 10−15 mol L−1. This study features the DNA intercalation-enabled organic electronics with superior gain and is envisaged to attract more attention to explore DNA adducts for innovative bioelectronics and biosensing, given the diverse DNA binders with multiple functions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•The effect of disinfectant-glutaraldehyde on the PN-ANAMMOX process was assessed.•Glutaraldehyde caused the anammox bacteria eroded from granule to flocus.•Glutaraldehyde alters ...nitrogen metabolism pathways and causes the increase of nir and nor genes.•NodT related efflux pumps replacing TolC related ones may be potential resistance mechanism.•Anammox bacteria lacked the NodT proteins and was sensitive to Glutaraldehyde.
A 160-day incubation was performed with two anammox reactors (GA and CK) to investigate the effect of glutaraldehyde. The results indicated that anammox bacteria were very sensitive when glutaraldehyde in GA reactor increased to 40 mg/L, the nitrogen removal efficiency sharply decreased to 11%, only one-quarter of CK. Glutaraldehyde changed spatial distribution of exopolysaccharides, caused anammox bacteria (Brocadia CK_gra75) to disassociate from granules (24.70% of the reads in CK but only 14.09% in GA granules). Metagenome analysis indicated glutaraldehyde led to the denitrifier community succession from strains without nir (nitrite reductase) and nor (nitric oxide reductases) genes to those with them, and the rapid growth of denitrifiers with NodT (an outer membrane factor)-related efflux pumps replacing those with another TolC -related ones. Meanwhile, Brocadia CK_gra75 lacks the NodT proteins. This study provides important insight into community adaptation and potential resistance mechanism in an active anammox community after exposure to disinfectant.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Two‐dimensional (2D) materials are highly sensitive to substrates, interfaces, and the surrounding environments. Suspended 2D materials are free from substrate‐induced effects, thus an ideal approach ...to study their intrinsic properties. However, it is very challenging to prepare large‐area suspended 2D materials with high efficiency. Here we report a universal method, based on pretreatments of densely patterned hole array substrates with either oxygen‐plasma or gold film deposition, to prepare large‐area suspended mono‐ and few‐layer 2D materials. Multiple structural, optical, and electrical characterization tools were used to fully evaluate the improved performance of various suspended 2D layers. Some of these observations reported in this study are: (1) Observation of a new Raman low frequency mode for the suspended MoS2; (2) Significantly stronger photoluminescence (PL) and second harmonic generation (SHG) signals of suspended WSe2, which enables the study of new optical transition processes; (3) The low energy electron diffraction pattern on suspended MoS2 also exhibits much sharper spots than that on the supported area; and (4) The mobility of suspended graphene device approaches 300 000 cm2 V−1 s−1, which is desirable to explore the intrinsic properties of graphene. This work provides an innovative and efficient route for fabricating suspended 2D materials, and we expect that it can be broadly used for studying intrinsic properties of 2D materials and in applications of hybrid active nanophotonic and electronic devices.
A new efficient method to fabricate high‐quality and large‐area suspended two‐dimensional (2D) materials is developed. The superior properties of suspended samples over supported ones are proved by Raman spectra, photoluminescence spectra, second harmonic generation, low energy electron microscopy as well as mobility characterization. This work could facilitate the studies of the intrinsic properties of 2D materials and the applications of active 2D nano devices.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Summary
Immune‐mediated thrombotic thrombocytopenic purpura (iTTP) is a rare and life‐threatening haematological emergency. Although therapeutic plasma exchange together with corticosteroids achieve ...successful outcomes, a considerable number of patients remain refractory to this treatment and require early initiation of intensive therapy. However, a method for the early identification of refractory iTTP is not available. To develop and validate a model for predicting the probability of refractory iTTP, a cohort of 265 consecutive iTTP patients from 17 large medical centres was retrospectively identified. The derivation cohort included 94 patients from 11 medical centres. For the validation cohort, we included 40 patients from the other six medical centres using geographical validation. An easy‐to‐use risk score system was generated, and its performance was assessed using internal and external validation cohorts. In the multivariable logistic analysis of the derivation cohort, three candidate predictors were entered into the final prediction model: age, haemoglobin and creatinine. The prediction model had an area under the curve of 0.886 (95% CI: 0.679–0.974) in the internal validation cohort and 0.862 (95% CI: 0.625–0.999) in the external validation cohort. The calibration plots showed a high agreement between the predicted and observed outcomes. In conclusion, we developed and validated a highly accurate prediction model for the early identification of refractory iTTP. It has the potential to guide tailored therapy and is a step towards more personalized medicine.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
p-Hydroxybenzaldehyde thiosemicarbazone (HBT) and p-methoxybenzaldehyde thiosemicarbazone (MBT) were synthesized and established by 1H NMR and mass spectra. Both compounds were evaluated for their ...inhibition activities on mushroom tyrosinase and free-cell tyrosinase and melanoma production from B16 mouse melanoma cells. Results showed that both compounds exhibited significant inhibitory effects on the enzyme activities. HBT and MBT decreased the steady state of the monophenolase activity sharply, and the IC50 values were estimated as 0.76 and 7.0 μM, respectively. MBT lengthened the lag time, but HBT could not. HBT and MBT inhibited diphenolase activity dose-dependently, and their IC50 values were estimated as 3.80 and 2.62 μM, respectively. Kinetic analyses showed that inhibition type by both compounds was reversible and their mechanisms were mixed-type. Their inhibition constants were also determined and compared. The research may supply the basis for the development of new food preservatives and cosmetic additives.
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IJS, KILJ, NUK, PNG, UL, UM, UPUK
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