Species divergence in seedling leaf traits and tree growth response to nitrogen and phosphorus additions in an evergreen broadleaved forest of subtropical China

Tree competitiveness generally depends on trait plasticity in response to environmental change.The effects of nitrogen(N)and phosphorus(P)on leaf trait variability by species is poorly understood,especially in China’s subtropical forests.This study examined the seedling leaf traits and net primary productivity of all trees>5 cm DBH of two dominant species,Schima superba and Castanopsis carlesii,in an evergreen broadleaved forest fertilized with nitrogen(+N),phosphorus(+P),and nitrogen plus phosphorus(N+P).The effect of N on seedling leaf traits was stronger than P,while fertilization in general was species dependent.Leaf mass per unit area decreased with N for S.superba seedlings but not for C.carlesii.Leaf N,P,and N/P ratios changed with N addition for both species.All four N fractions of carboxylation,bioenergetics,cell wall,and other N metabolites in C.carlesii leaves responded significantly to fertilization,while only the cell wall in S.superb a leaves responded.Other leaf functional traits,including light-saturated photosynthetic rates,water,N,and P use efficiencies,chlorophyll and non structural carbohydrate contents increased with N addition in S.superb a and by P addition in C.carlesii.Canopy closure at the stand-level increased due to N.Litter biomass and relative growth rate of S.superb a was not affected by any treatments,while both for C.carlesii significantly decreased with N+P addition.Collectively,nutrient limitation may vary at a small scale among species in a subtropical forest based on their responses of seedling traits and net primary productivity to fertilization.Seedling traits are not correlated with the net primary productivity of larger trees except for N fractions,because low light conditions induced by fertilization reduces the proportion of N allocated to photosynthesis in seedlings.In addition,acclimation differences of tree species may increase the uncertainty of community succession.

Lymphocytopenia and Neutrophilia Deteriorate at the Lowest Oxygenation Index Timepoint in COVID-19 Patient

Objective: Coronavirus disease 2019 (COVID-19) spread throughout the world and caused hundreds of thousands of infected people to death. However, the pathogenesis of severe acute respiratory syndrome coronavirus-2 (SARS COV-2) is poorly understood. The objective of this study is to retrospectively explore the pathogenesis of COVID-19 from clinical laboratory findings, taking disease progression into account. Methods: A single-centered, retrospective study was carried out, which included moderate (n = 76) and severe COVID-19 cases (n = 22). The difference of laboratory findings from blood routine examination and hepatorenal function test were retrospectively evaluated between the state of moderate and severe. The disease progression was indicated by oxygenation index. Results: Age is a risk factor for disease progression from moderate to severe. Lymphocytopenia, neutrophilia, liver and kidney function decreasement occurred in severe patients on admission, compared with moderate patients. Lymphocytopenia and neutrophilia deteriorated at the lowest oxygenation index timepoint in the severe patients. And the oxygenation index was associated with ratio of lymphocyte and neutrophil in COVID-19 patients. Conclusions: Lymphocytopenia and neutrophilia, which deteriorate in the progression of severe patients, are the main pathogenesis of COVID-19. More measures need to be taken to control lymphocytopenia and neutrophilia in severe COVID-19. Oxygenation index presented potentiality as predictor on the progression of COVID-19.

Simultaneous passivation of bulk and interface defects through synergistic effect of anion and cation toward efficient and stable planar perovskite solar cells

Bulk and interface carrier nonradiative recombination losses impede the further improvement of power conversion efficiency(PCE)and stability of perovskite solar cells(PSCs).It is highly necessary to develop multifunctional strategy to minimize surface and interface nonradiative recombination losses.Herein,we report a bulk and interface defect passivation strategy via the synergistic effect of anions and cations,where multifunctional potassium sulphate(K_(2)SO_(4))is incorporated at SnO_(2)/perovskite interface.We find that K^(+)ions in K_(2)SO_(4)diffuse into perovskite layer and suppress the formation of bulk defects in perovskite films,and the SO_(4)^(2-)ions remain located at interface via the strong chemical interaction with SnO_(2)layer and perovskite layer,respectively.Through this synergistic modification strategy,effective defect passivation and improved energy band alignment are achieved simultaneously.These beneficial effects are translated into an efficiency increase from 19.45%to 21.18%with a low voltage deficit of0.53 V mainly as a result of boosted open-circuit voltage(V_(oc))after K_(2)SO_(4)modification.In addition,the K_(2)SO_(4)modification contributes to ameliorated stability.The present work provides a route to minimize bulk and interface nonradiative recombination losses for the simultaneous realization of PCE and stability enhancement by rational anion and cation synergistic engineering.

Enabling stable sodium metal cycling by sodiophilic interphase in a polymer electrolyte system

Enabling highly reversible sodium(Na) metal anodes in a polymer electrolyte(PE) system is critical for realizing next-generation batteries with lower cost,higher energy,and improved safety.However,the uneven Na deposition and high Na/PE interphase resistance lead to poor reversibility and short cycle life of Na metal anodes.To tackle these problems,here a variety of metal nanoparticles(M-np,M=Al,Sn,In or Au) are deposited onto copper(Cu) foils to synthesize binder-free M-np@Cu substrates for Na plating/stripping.Notably,the Au-np@Cu substrate provides abundant preferential nucleation/growth sites,decreasing Na nucleation barrier and thus promoting uniform Na deposition.Accordingly,stable Na metal anodes are achieved with high reversible capacities,long cycle life,and high usage of Na.With the Au-np@Cu/Na anode and PE,the full cell using a commercial bulk sulfur cathode exhibits a reversible capacity of>400 mAh g^(-1) with near-100% Coulombic efficiency over 200 cycles.

Radial integral boundary element method for simulating phase change problem with mushy zone

A radial integral boundary element method(BEM)is used to simulate the phase change problem with a mushy zone in this paper.Three phases,including the solid phase,the liquid phase,and the mushy zone,are considered in the phase change problem.First,according to the continuity conditions of temperature and its gradient on the liquid-mushy interface,the mushy zone and the liquid phase in the simulation can be considered as a whole part,namely,the non-solid phase,and the change of latent heat is approximated by heat source which is dependent on temperature.Then,the precise integration BEM is used to obtain the differential equations in the solid phase zone and the non-solid phase zone,respectively.Moreover,an iterative predictor-corrector precise integration method(PIM)is needed to solve the differential equations and obtain the temperature field and the heat flux on the boundary.According to an energy balance equation and the velocity of the interface between the solid phase and the mushy zone,the front-tracking method is used to track the move of the interface.The interface between the liquid phase and the mushy zone is obtained by interpolation of the temperature field.Finally,four numerical examples are provided to assess the performance of the proposed numerical method.

Effect of roasting activation of rare earth molten salt slag on extraction of rare earth,lithium and fluorine

A new process was proposed to extract rare earth elements(REEs),Li and F from electrolytic slag of rare earth molten salt by synergistic roasting and acid leaching.Firstly,the thermodynamic analysis of roasting reaction was carried out,then the effects of roasting factors on leaching REEs,Li and F in slag were investigated.In additions,the mineral phase and morphology of molten salt slag,roasting slag and acid leaching slag were characterized,and the migration mechanism of REES,Li and F minerals in roasting and leaching process was analyzed.The results show that the synergistic roasting and activation of molten salt slag by CaO and Al_(2)(SO_(4))_(3)are thermodynamically feasible.The optimum roasting conditions are as follows:molten salt slag of 20 g,Al_(2)(SO_(4))_(3)of 31.25 g and CaO of 6.25 g,roasting temperature of 1173.15 K and reaction time of 2 h,under this condition,the leaching rates of Nd,Pr,Gd,Li and F are 92.47%,91.56%,91.08%,96.69%and 96.8%,respectively.X-ray powder diffraction(XRD)and scanning electron microscopy-energy dispersive X-ray spectroscopy(SEM-EDS)analysis show that the rare earth fluoride(REF3)in molten salt slag transforms into soluble rare earth oxide(REO)after roasting and activation.After leaching,the leaching residue is mainly strip CaSO4,indicating that REES,Li and F can be fully extracted from molten salt slag.

Hybrid metasurface using graphene/graphitic carbon nitride heterojunctions for ultrasensitive terahertz biosensors with tunable energy band structure

Integrating novel materials is critical for the ultrasensitive,multi-dimensional detection of biomolecules in the terahertz(THz)range.Few studies on THz biosensors have used semiconductive active layers with tunable energy band structures.In this study,we demonstrate three THz biosensors for detecting casein molecules based on the hybridization of the metasurface with graphitic carbon nitride,graphene,and heterojunction.We achieved lowconcentration detection of casein molecules with a 3.54 ng/m L limit and multi-dimensional sensing by observing three degrees of variations(frequency shift,transmission difference,and phase difference).The favorable effect of casein on the conductivity of the semiconductive active layer can be used to explain the internal sensing mechanism.The incorporation of protein molecules changes the carrier concentration on the surface of the semiconductor active layer via the electrostatic doping effect as the concentration of positively charged casein grows,which alters the energy band structure and the conductivity of the active layer.The measured results indicate that any casein concentration can be distinguished directly by observing variations in resonance frequency,transmission value,and phase difference.With the heterojunction,the biosensor showed the highest response to the protein among the three biosensors.The Silvaco Atlas package was used to simulate the three samples'energy band structure and carrier transport to demonstrate the benefits of the heterojunction for the sensor.The simulation results validated our proposed theoretical mechanism model.Our proposed biosensors could provide a novel approach for THz metasurface-based ultrasensitive biosensing technologies.

Design of the rare-earth-containing materials based on the micro-alloying phase equilibria, phase diagrams and phase transformations

Rare-earth(RE)elements,known as“industrial vitamins”,have permeated modern lives,especially in high-tech applications.Although the RE elements possess close chemical similarities and have been treated as“one element”in the periodic table,their characteristics differ from each other.The RE microalloying effect is the crux to ameliorate the physicomechanical and thermochemical properties of materials,thereby the study of RE-related phase diagrams becomes indispensable to the design and optimization of RE-containing materials.However,in reality,the knowledge base in this area is considerably scarce compared with that of other commonly-used elements.In this work,the phase equilibria,phase diagrams,phase transformations,and some recent examples of RE-containing materials design are summarized,with which one can predict the RE solubilities,the RE precipitates,as well as the corresponding service behaviors.The attainment of enhanced materials’properties suggests that the thermodynamic rules extracted from the phase diagrams could serve as fundamental criteria for the successful development of novel RE-containing materials.

Associating Preoperative MRI Features and Gene Expression Signatures of Early-stage Hepatocellular Carcinoma Patients using Machine Learning

Background and Aims:The relationship between quanti-tative magnetic resonance imaging(MRI)imaging features and gene-expression signatures associated with the recur-rence of hepatocellular carcinoma(HCC)is not well studied.Methods:In this study,we generated multivariable regres-sion models to explore the correlation between the preoper-ative MRI features and Golgi membrane protein 1(GOLM1),SET domain containing 7(SETD7),and Rho family GTPase 1(RND1)gene expression levels in a cohort study including 92 early-stage HCC patients.A total of 307 imaging features of tumor texture and shape were computed from T2-weighted MRI.The key MRI features were identified by performing a multi-step feature selection procedure including the cor-relation analysis and the application of RELIEFF algorithm.Afterward,regression models were generated using kernel-based support vector machines with 5-fold cross-validation.Results:The features computed from higher specificity MRI better described GOLM1 and RND1 gene-expression levels,while imaging features computed from lower specificity MRI data were more descriptive for the SETD7 gene.The GOLM1 regression model generated with three features demon-strated a moderate positive correlation(p<0.001),and the RND1 model developed with five variables was positively as-sociated(p<0.001)with gene expression levels.Moreover,RND1 regression model integrating four features was mod-erately correlated with expressed RND1 levels(p<0.001).Conclusions:The results demonstrated that MRI radiomics features could help quantify GOLM1,SETD7,and RND1 ex-pression levels noninvasively and predict the recurrence risk for early-stage HCC patients.

Preoperative Assessment of Abdominal Adipose Tissue to Predict Microvascular Invasion in Small Hepatocellular Carcinoma

Background and Aims:Microvascular invasion(MVI)affects recurrence after treatment of small hepatocellular carcinoma(sHCC)of≤3 cm in size.The present study aimed to investigate whether abdominal subcutaneous adipose tissue(SAT),visceral adipose tissue(VAT),and intermuscular adipose tissue(IMAT)are associated with MVI in patients with sHCC.Methods:A total of 124 patients with pathologicallyconfirmed sHCC diagnosed on surgical resection at the First Hospital Affiliated to Army Military University were recruited and divided into two groups according to MVI classification criteria(i.e.,MVI-positive or MVI-negative).The SAT,VAT,and IMAT areas at the lumbar 3 vertebral level were imaged with abdominal computed tomography and measured using ImageJ software.Their association with MVI in sHCC was analyzed.Results:Of the 124 patients with sHCC,67 were MVIpositive and 57 were MVInegative.Univariate analysis revealed a significant difference in the abdominal VAT and SAT between the MVI-positive and MVI-negative groups(p<0.05),with an area under the receiver operating characteristic curve of 0.76 and 0.65,respectively.Conclusions:The results of this study suggest that the areas of abdominal SAT and VAT are of significant clinical value because they can effectively predict the MVI status in patients with sHCC.

Tuning the local electronic structure of oxygen vacancies over copper-doped zinc oxide for efficient CO_(2) electroreduction

Oxygen vacancies in metal oxides can serve as electron trap centers to capture CO_(2) and lower energy barriers for the electrochemical CO_(2) reduction reaction(CO_(2)RR).Under aqueous electrolytes,however,such charge-enriched active sites can be occupied by adsorbed hydrogen(H∗)and lose their effectiveness for the CO_(2)RR.Here,we develop an efficient catalyst consisting of Cu-doped,defect-rich ZnO(Cu–ZnO)for the CO_(2)RR,which exhibits enhanced CO Faradaic efficiency and current density compared to pristine ZnO.The introduced Cu dopants simultaneously stabilize neighboring oxygen vacancies and modulate their local electronic structure,achieving inhibition of hydrogen evolution and acceleration of the CO_(2)RR.In a flow cell test,a current density of more than 45​mA​cm^(−2) and a CO Faradaic efficiency of>80%is obtained for a Cu–ZnO electrocatalyst in the wide potential range of−0.76​V to−1.06​V vs.Reversible Hydrogen Electrode(RHE).This work opens up great opportunities for dopant-modulated metal oxide catalysts for the CO_(2)RR.

凋落物年龄和氮、磷添加交互作用对杉木林土壤N_(2)O排放的影响

氧化亚氮(N_(2)O)是一种重要的温室气体,增温潜势较大,其浓度增加影响全球气候变化。由于凋落物分解影响碳和养分循环,土壤N_(2)O排放受凋落物分解作用,而凋落物年龄和氮、磷添加影响凋落物分解,潜在影响土壤N_(2)O的排放。然而,凋落物年龄和养分添加对土壤N_(2)O排放的交互作用及其机制目前还没有报道,这限制了凋落物分解对N_(2)O排放的影响评价。本研究以杉木(Cunninghamia lanceolata)不同年龄凋落物为研究对象,通过氮、磷添加处理,研究了养分和凋落物年龄对N_(2)O排放的影响及其机制。研究结果显示,幼龄凋落物主要通过调节碳氮比来影响N_(2)O排放。氮添加主要通过调节凋落物碳氮比、土壤pH以及与N_(2)O产生相关的微生物功能基因所编码的土壤酶活性来影响N_(2)O排放,整体上促进N_(2)O排放。磷添加显著降低凋落物碳氮比,进而作用于N_(2)O排放,该途径促进N_(2)O排放。同时,磷添加提高土壤有效磷水平,潜在降低N_(2)O排放,整体上降低土壤N_(2)O排放。凋落物年龄和养分添加交互作用于土壤N_(2)O排放。因此,在森林经营管理中,评价不同管理措施,尤其是间伐和选择性砍伐等导致不同凋落物输入的管理活动对土壤N_(2)O排放的影响时,应同时考虑养分输入和凋落物年龄的潜在影响。

STRESS SINGULARITY ANALYSIS OF MULTI-MATERIAL WEDGES UNDER ANTIPLANE DEFORMATION

With the help of the coordinate transformation technique, the symplectic dual solv- ing system is developed for multi-material wedges under antiplane deformation. A virtue of present method is that the compatibility conditions at interfaces of a multi-material wedge are expressed directly by the dual variables, therefore the governing equation of eigenvalue can be derived easily even with the increase of the material number. Then, stress singularity on multi-material wedges under antiplane deformation is investigated, and some solutions can be presented to show the validity of the method. Simultaneously, an interesting phenomenon is found and proved strictly that one of the singularities of a special five-material wedge is independent of the crack direction.

Intrinsic-trap-regulating growth of clean graphene on high-entropy alloy substrate

A facile way to grow few-layer graphene on high-entropy alloy sheets is presented in this work.We systematically investigate the growth mechanism of graphene using the unique properties of FeCoNiCu_(0.25)high-entropy alloys.The intrinsic-trap-regulating growth mechanism derives from the synergistic effect of the multi-metal atoms and sluggish diffusion of high-entropy alloy.As a result,as-obtained few-layer of graphene has the characteristics of wide coverage,large size,good continuity,and high crystallinity with less amorphous carbon and extra wrinkles.Factors such as the Cu content,annealing time,growth temperature,growth time,carbon source flow rate,hydrogen flow rate and heat treatment method play a key role in the growth of high-quality graphene,and the best growth parameters have been explored.Besides,increasing alloy entropy is found to be responsible for the formation of high-quality graphene.