Copper-catalyzed C(sp)-H aryl amination enables modular synthesis of quinolines and 2-quinolinones

Herein,we disclose a novel copper-catalyzed C(sp)-H aryl amination of terminal alkynes with anthranils,enabling the rapid generation of highly reactive secondary N-aryl ynamines for the modular synthesis of structurally diverse C2-substituted quinolines and 2-quinolinones.The in-situ formed carbonyl-ynamines are prone to tautomerize to carbonyl-ketenimines,which can efficiently react with a series of nucleophiles,including amines,alcohols,phenols,thiols,thiophenols,active-methylene compounds,and even water to produce various quinoline derivatives with the generation of H_(2)O as a sole and green byproduct.This method also unlocks a practical route to create various quinoline-fused heterocycles and can be successfully applied to the late-stage modification of complex molecules and the concise synthesis of bioactive targets.Mechanistic studies reveal a coppercatalyzed inner-sphere nitrene transfer process by using anthranils as novel aryl nitrene precursors.

OsADR3 increases drought stress tolerance by inducing antioxidant defense mechanisms and regulating OsGPX1 in rice(Oryza sativa L.)

The C (Cys) 2H (His) 2-type transcription factor is one of the most important transcription factors in plants and plays a regulatory role in the physiological responses of rice to abiotic stresses.A novel rice C2H2-type zinc finger protein,abscisic acid (ABA)-drought-reactive oxygen species (ROS) 3 (OsADR3),was found to confer drought stress tolerance by enhancing antioxidant defense and regulating Os GPX1.Overexpression of OsADR3 in rice increased tolerance to drought stress by increasing ROS scavenging ability and ABA sensitivity.In contrast,CRISPR/Cas9-mediated knockout of osadr3 increased the sensitivity of rice to drought and oxidative stress.An exogenous ROS-scavenging reagent restored the droughtstress tolerance of osadr3-CRISPR plants.Global transcriptome analysis suggested that OsADR3 increased the expression of Os GPX1 under drought stress.Electrophoretic mobility shift,yeast one-hybrid,and dualluciferase reporter assays revealed that OsADR3 modified the expression of Os GPX1 by directly binding to its promoter.Knockdown of Os GPX1 repressed ROS scavenging ability under drought stress in OsADR3-overexpression plants.These findings suggest that OsADR3 plays a positive regulatory role in droughtstress tolerance by inducing antioxidant defense and associated with the ABA signaling pathway in rice.

Effect of thinning intensity on the stem CO_(2) efflux of Larix principis-rupprechtii Mayr

Background:Stem CO_(2) efflux(E_(S))plays a critical role in the carbon budget of forest ecosystems.Thinning is a core practice for sustainable management of plantations.It is therefore necessary and urgent to study the effect and mechanism of thinning intensity(TI)on E_(S).Methods:In this study,five TIs were applied in Larix principis-rupprechtii Mayr 21-,25-,and 41-year-old stands in North China in 2010.Portable infrared gas analyzer(Li-8100 A)was used to measure ES and its association with environmental factors at monthly intervals from May to October in 2013 to 2015.In addition,nutrients,wood structure and nonstructural carbon(NSC)data were measured in August 2016.Results:The results show that ES increased with increasing TI.The maximum ES values occurred at a TI of 35%(3.29,4.57 and 2.98μmol·m^(-2)·s^(-1))and were 1.54-,1.94-and 2.89-fold greater than the minimum E_(S) value in the CK stands(2.14,2.35 and 1.03μmol·m^(-2)·s^(-1))in July for the 21-,25-and 41-year-old forests,respectively.The E_(S) of the trees in low-density stands was more sensitive to temperature than that of the trees in high-density stands.Soluble sugars(SS)and temperature are the main factors affecting ES.When the stand density is low enough as 41-year-old L.principis-rupprechtii forests with TI 35%,bark thickness(BT)and humidity should be considered in addition to air temperature(T_(a)),wood temperature(T_(w)),sapwood width(SW),nitrogen concentration(N)and SS in the evaluation of ES.If a change in stand density is ignored,the CO_(2) released from individual 21-,25-and 41-year-old trees could be underestimated by 168.89%,101.94% and 200.49%,respectively.CO_(2) release was estimated based on the stem equation in combination with the factors influencing ES for reference.Conclusions:We suggest that it is not sufficient to conventional models which quantify ES only by temperature and that incorporating the associated drivers(e.g.density,SS,SW and N)based on stand density into conventional models can improve the accuracy of ES estimates.

Consistent response of nematode communities to management of coniferous plantations

Background:Crop-tree thinning (CTT) is a forest management practice aiming at enhancing the growth of target trees in plantations by harvesting neighboring trees. Along with the positive effect on tree growth, thinning represents a disturbance, which likely affects belowground organisms and may feed back to stand productivity.However, the impact of CTT on the belowground food web is poorly understood. Since nematodes are species-rich and abundant belowground organisms, occupying a variety of trophic positions in soil food webs and being sensitive to disturbances, they serve as ecological indicators of ecosystem disturbance.Results:We studied the effect of CTT on the soil nematode community structure in pine (Pinus massoniana Lamb.),Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) and cypress (Cupressus funebris Endl.) plantations in the Sichuan Basin three years after applying CTT. Crop-tree thinning significantly increased the abundance of soil nematodes in each of the plantations. Moreover, CTT significantly increased the relative abundance of herbivorous nematodes in each of the plantations. Furthermore, CTT increased the proportion of stress tolerators (c-p 1)and enrichment opportunists (c-p 2) and reduced the maturity, structure and enrichment indices of nematodes in Chinese fir and cypress plantations, while only subtle changes were observed in pine plantations. Interestingly,across plantations, the effects of CTT on soil nematode communities were mainly due to changes in microbial biomass nitrogen and understory vegetation diversity.Conclusions:Forest management practices resulting in more open canopies uniformly affect soil food webs by changing the quantity and quality of resources associated with increased understory cover and diversity as well as microbial food. These insights increase our understanding of the impacts of forest management on the structure and functioning of belowground communities, which may contribute to management and conservation policies for more sustainable forestry.

A Distributed ADMM Approach for Collaborative Regression Learning in Edge Computing

With the recent proliferation of Internet-of-Things(IoT),enormous amount of data are produced by wireless sensors and connected devices at the edge of network.Conventional cloud computing raises serious concerns on communication latency,bandwidth cost,and data privacy.To address these issues,edge computing has been introduced as a new paradigm that allows computation and analysis to be performed in close proximity with data sources.In this paper,we study how to conduct regression analysis when the training samples are kept private at source devices.Specifically,we consider the lasso regression model that has been widely adopted for prediction and forecasting based on information gathered from sensors.By adopting the Alternating Direction Method of Multipliers(ADMM),we decompose the original regression problem into a set of subproblems,each of which can be solved by an IoT device using its local data information.During the iterative solving process,the participating device only needs to provide some intermediate results to the edge server for lasso training.Extensive experiments based on two datasets are conducted to demonstrate the efficacy and efficiency of our proposed scheme.

A Novel Improved Bat Algorithm in UAV Path Planning

Path planning algorithm is the key point to UAV path planning scenario.Many traditional path planning methods still suffer from low convergence rate and insufficient robustness.In this paper,three main methods are contributed to solving these problems.First,the improved artificial potential field(APF)method is adopted to accelerate the convergence process of the bat’s position update.Second,the optimal success rate strategy is proposed to improve the adaptive inertia weight of bat algorithm.Third chaos strategy is proposed to avoid falling into a local optimum.Compared with standard APF and chaos strategy in UAV path planning scenarios,the improved algorithm CPFIBA(The improved artificial potential field method combined with chaotic bat algorithm,CPFIBA)significantly increases the success rate of finding suitable planning path and decrease the convergence time.Simulation results show that the proposed algorithm also has great robustness for processing with path planning problems.Meanwhile,it overcomes the shortcomings of the traditional meta-heuristic algorithms,as their convergence process is the potential to fall into a local optimum.From the simulation,we can see also obverse that the proposed CPFIBA provides better performance than BA and DEBA in problems of UAV path planning.

Morphological Characteristics and Nutrient Content of Fine Roots of 2-Year-Old and 3-Year-Old Eucalyptus grandis Plantation

[Objective]This study aimed to explore the morphological characteristics and nutrient content of fine roots of 2-year-old and 3-year-old Eucalyptus grandis plantation and investigate the correlation.[Method] Fine roots of 2-year-old and 3-year-old Eucalyptus grandis plantation were collected as experimental materials,to determine the root diameter (D),root length (L),specific root length (SRL) and contents of major nutrient elements N,P,K,Ca,Mg and C of fine roots (level1-5),study the morphological characteristics and major nutrient element content and investigate the correlation.[Result] The results showed that morphological differences of fine roots (level1-5) of Eucalyptus grandis plantation were great with the increase of root order,to be specific,D and L increased and SRL decreased with the increasing root order;SRL,L and D of 3-year-old Eucalyptus grandis plantation were greater than those of 2-year-old Eucalyptus grandis plantation. Contents of N,Ca,Mg and C of fine roots of 2-year-old and 3-year-old Eucalyptus grandis plantation showed consistent orders with the increase of root order:N and Mg contents were reduced,while Ca and C contents were enhanced;P and K contents varied with different forest ages;both 2-year-old and 3-year-old Eucalyptus grandis showed an order of C > K > Ca ( Mg) > N. Major nutrient element content and morphological characteristics of Eucalyptus grandis fine roots (level1-5) were extremely significantly correlated (P < 0. 01),SRL,L and D could be adopted as reference indices to evaluate nutrient status of Eucalyptus grandis.Required nutrients and fine root morphology of Eucalyptus grandis plantation changed with the increase of forest age,and the nutrient cycling and energy flow patterns also changed; major nutrient elements in fine roots of 2-year-old and 3-year-old Eucalyptus grandis plantation transferred in a different order from the growth order,therefore N fertilizer could be applied to improve the growth of fine roots.[Conclusion]This study laid the foundation for understanding the fine root morphology and nutrient variation pattern of Eucalyptus grandis plantation and enriching the response and adaptation mechanism theory of roots to environment,possessing important reference significance for the sustainable development of Eucalyptus grandis plantation.

Thermodynamic parameters of 135 gaseous PCDF calculated with DFT

Numerous thermal processes(e.g.waste incineration,steel and nonferrous industry,wastes recycling plants,hot dip galvanizing etc.)have been identified as emission sources of PolyChlorinated Dibenzo-p-Dioxins (PCDD)and PolyChlorinated DibenzoFurans(PCDF),which are named in brief'dioxins'.The processes by which such dioxins(PCDD/F)are formed are still incompletely understood and probably proceed catalytically by multiple and parallel pathways.However,two major pathways of formation have been identified during final stages of the combustion process:The first one is the precursor route,i.e.the formation of PCDD/F from related structures, such as simple or chlorinated benzenes,phenols,biphenyls,and polycyclic aromatic hydrocarbons(PAH),and the second one is the de nov,9 synthesis of PCDD/F from macromolecular solid carbon(or other structures unrelated to dioxins),organic and inorganic chlorine,oxygen,etc. Knowledge of the relevant thermodynamic parameters is essential for predicting possible stability domains of PCDD/F during combustion processes and their equilibrium distribution at emission sources. In the previous study,thermodynamic parameters of PCDD predicted with density functional theory(DFT) method have been reported.A comprehensive thermodynamic database of the standard entropy(S^o),specific heat (C_p),enthalpy of formation(Δ_fH^o)and Gibbs free energy of formation(Δ_fG^o)for 135 gaseous PCDF( including dibenzofuran)was studied.From the enthalpies of formation the order of stability of individual congeners is reported. Additionally,the results obtained in this study are compared with values determined by other electronic structural methods.

Calculation of thermodynamic parameters of 75 gaseous PCDDs using the density functional theory

In this paper,the thermodynamic parameters are calculated for all gaseous Poly Chlorinat Dibenzo-p-dioxins (PCDDs)using the Density Functional Theory(DFT)method and both the enthalpy of formation(Δ_fH^o)and Gibbs free energy of formation(Δ_fG^o)are derived,from which the order of stability of individual congeners is then predicted.All these properties,together with the calculated entropies(S^o)and heat capacities(C_p),are presented as a function of the number of chlorine atoms in the various PCDD molecules.The accuracy of the method used here,is evaluated by comparing the thermodynamic parameters of gaseous chlorobenzenes with experimental values collected from literature.

A Cu/Cinchona P,N-ligand system enabled general asymmetric C(sp^3)–C(sp) coupling

Due to the special structural feature and versatile reactivity towards various types of transformations,alkynes have inspired continuous research interest for their generation,incorporation and application in organic synthesis,chemical biology and material science[1].Notably,since its invention in 1975,the Sonogashira reaction,which efficiently couples aryl halides with aryl or vinyl terminal alkynes via Pd(0)/Cu(I)synergistic catalysis.

An improved method that incorporates the estimated runoff for peak discharge prediction on the Chinese Loess Plateau

An accurate prediction of peak discharge in watersheds is critical not only for water resource manage-ment,but also for understanding the complex relationships of hydrological processes.In this study,a modified peak discharge formula based on the Chemicals,Runoff,and Erosion from Agricultural Man-agement Systems(CREAMS)model was developed by introducing rainfall intensity and soil moisture factors.The reliability of the proposed method was tested with data from 1464 storm events in 41 watersheds and was applied to 256 storm events in five remaining typical watersheds using the opti-mized parameters.The results indicate that the proposed method is highly accurate in terms of model efficiency,as determined by Nash-Sutcliffe efficiencies(NSEs)of 88.60%,74.04%,and 90.12%during the calibration,validation,and application cases,respectively.Furthermore,it performed better than the original and modified CREAMS methods.Subsequently,using the parameters derived from the initial 41 watersheds and the runoff estimated using the modified Soil Conservation Service curve number(SCS-CN)method,the proposed method was used to predict the peak discharge from the last five typical watersheds.Large NSE(63.88-80.83%)and low root mean square error(RMSE)values(0.31-35.93 m^(3)s^(-1))were obtained for the five watersheds.Overall,the proposed peak discharge model,combined with the modified SCS-CN method,may accurately predict event-based peak discharge and runoff for general applications under various hydrological and geomorphic conditions in the Loess Plateau region.

The ignored emission of volatile organic compounds from iron ore sinter process

Iron ore sintering is a major source of gaseous and particulate pollutants emission in iron smelt plant. The aim of present study is to characterize the volatile organic compounds(VOCs) emission profiles from iron ore sintering process. Both sinter pot test and sinter simulation experiment were conducted and compared. Out results showed that sinter process produced large quantity of VOCs together with NOxand SO_2. VOCs and NO were produced simultaneously in sinter pot test from 3 to 24 min after ignition, flowed by SO_2 production from 15 min to the end of sintering. Total VOCs(TVOC) concentration in sinter flue gas was affected by the coal and coke ratio in sinter raw material. The maximum TVOC concentration was 34.5 ppm when using 100% coal as fuel. Sinter simulation experiments found that the number of VOCs species and their concentrations were found by sinter temperature. The largest VOCs species varieties were obtained at 500 °C. Benzene, toluene,xylene and ethylbenzene were major VOCs in sinter flue gas based on the results from both simulation test and sinter pot. It thus demonstrated that in addition to NO_x, SO_2 and metal oxide particles, sinter flue gas also contained significant amount of VOCs whose environmental impact cannot be ignored. Based on our work, it is timely needed to establish a new VOC emission standard for sinter flue gas and develop advanced techniques to simultaneously eliminate multi-pollutants in iron ore sinter process.

Further control synthesis for time-delay systems with actuator saturation

This paper is concerned with the control synthesis problem for systems with time-varying delay and actuator saturation. A new controller design method is proposed in which auxiliary feedback matrix method is adopted to handle the saturation term in the system. The improvement of the proposed method lies in the application of delay partitioning idea to further enlarge the estimated domain of attraction. All the results are given in terms of linear matrix inequalities. Finally, a numerical example is provided to demonstrate the effectiveness and superiority of our obtained results.