Cotton is an important global cash crops that serve as the primary source of natural fiber for textiles.A thorough understand-ing of the long-term variations in cotton cultivation is vital for optimizing cotton cultiv...Cotton is an important global cash crops that serve as the primary source of natural fiber for textiles.A thorough understand-ing of the long-term variations in cotton cultivation is vital for optimizing cotton cultivation management and promoting the sustainable development of the cotton industry.Xinjiang is the primary cotton-producing region in China.However,long-term data of cotton cultiv-ation areas with high spatial resolution are unavailable for Xinjiang,China.Therefore,this study aimed to identify and map an accurate 30-m cotton cultivation area dataset in Xinjiang from 2000 to 2020 by applying a Random Forest(RF)-based method that integrates Landsat and Moderate Resolution Imaging Spectroradiometer(MODIS)images,and validated the applicability and accuracy of dataset at a large spatial scale.Then,this study analyzed the spatiotemporal variations and influencing factors of cotton cultivation in the study period.The results showed that a high classification accuracy was achieved(overall accuracy>85%,F1>0.80),strongly agreeing with county-level agricultural statistical yearbook data(R2>0.72).Significant spatiotemporal variation in the cotton cultivation areas was found in Xinjiang,with a total increase of 1131.26 kha from 2000 to 2020.Notably,cotton cultivation area in southern Xinjiang expan-ded substantially,with that in Aksu increasing from 20.10%in 2000 to 28.17%in 2020,representing an expansion of 374.29 kha.In northern Xinjiang,the cotton areas in the Tacheng region also exhibited significant increased by almost ten percentage points in the same period.In contrast,cotton cultivation in eastern Xinjiang declined,decreasing from 2.22%in 2000 to merely 0.24%in 2020.Standard deviation ellipse analysis revealed a‘northeast-southwest’spatial distribution,with the centroid consistently located in Aksu and shifting 102.96 km over the 20-yr period.Pearson correlation analysis indicated that socioeconomic factors had a stronger influence on cotton cultivation than climatic factors,with effective irrigation area(r=0.963,P<0.05)and total agricultural machinery power(r=0.823)showing significant positive correlations,whereas climatic variables exhibiting weak associations(r<0.200).These results provide valuable scientific data for informed agricultural management,sustainable development,and policymaking.展开更多
Objectives:Adults with cataracts are often reported with mental health issues,which has driven researchers to identify modifiable factors so that effective intervention programs can be timely implemented.Thus,we inves...Objectives:Adults with cataracts are often reported with mental health issues,which has driven researchers to identify modifiable factors so that effective intervention programs can be timely implemented.Thus,we investigated associations of physical activity(PA)and sedentary behavior(SB)with stress,anxiety,and sleep problems among adultswith cataracts.Methods:In this cross-sectional study,a total of 2219 participantswith cataracts completed self-reported measures on demographic characteristics(e.g.,age and sex),PA,SB,anxiety,stress and sleep problems.Multiple linear regression and logistic analyses adjusted for covariates were employed to examine the associations of PA and SB with outcomes of interest.Results:Meeting PA recommendation was significantly associated with lower stress score(β=−2.920,95%CI:−3.880 to−1.959;p<0.001),a 51.2%reduction in the odds of sleep problems(OR=0.488,95%CI:0.389 to 0.612;p<0.001).Limiting SB to≤8 h/day was significantly associated with reduced stress score(−5.191,95%CI:−6.378 to−4.004;p<0.001),lower odds of anxiety symptoms(OR=0.481,95%CI:0.354 to 0.655;p<0.001),and sleep problems(OR=0.540,95%CI:0.420 to 0.693;p<0.001).The greatest benefit appeared when both PA and SB recommendations were achieved simultaneously.Compared with individuals who met neither recommendation,those who were sufficiently active and sat less than 8 h/day showed a 9.307-point lower stress score(95%CI:−11.12 to−7.49;p<0.001),a 54.9%lower odds of anxiety symptoms(OR=0.451,95%CI:0.262 to 0.776;p=0.004),and a 66.4%lower odds of sleep problems(OR=0.336,95%CI:0.206 to 0.550;p<0.001).Conclusions:Meeting PA and SB recommendations could provide substantial psychosocial benefits for adults with cataracts.展开更多
The title compound, [NiL]5[V34O82·8H2O （1, L=5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane）, has been synthesized under hydrothermal conditions and structurally characterized by EA, IR, XPS, TG an...The title compound, [NiL]5[V34O82·8H2O （1, L=5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane）, has been synthesized under hydrothermal conditions and structurally characterized by EA, IR, XPS, TG and single-crystal X-ray diffraction. It crystallizes in the monoclinic system, space group C2/c with a=33.061（4）, b=15.3457（17）, c=33.902（4）, β=101.930（2）°, Mr=4904.08, V=16828（3）3 , Z=4, Dc=1.936 g/cm3 , F（000）=9832, μ=2.425 mm-1 , the final R=0.0402 and wR=0.0969. The mixed valence vanadium clusters of [V34O82]10- bridges [NiL]2＋ to form a one-dimensional chain in 1. To the best of our knowledge, the title complex is the first example of organic-inorganic hybrid material involving the largest vanadium cluster of [V34O82]10-.展开更多
The title compound（14 S）-2,14-diphenyl-6,6 a,11,12-tetrahydro-5 H,10 H,14 H-[1,8] naphthyridino[1,2-c]pyrido[3,2,1-ij]quinazoline-3-carbonitrile（C31 H26 N4, Mr = 454.56） has been synthesized with 2-aminonicotinald...The title compound（14 S）-2,14-diphenyl-6,6 a,11,12-tetrahydro-5 H,10 H,14 H-[1,8] naphthyridino[1,2-c]pyrido[3,2,1-ij]quinazoline-3-carbonitrile（C31 H26 N4, Mr = 454.56） has been synthesized with 2-aminonicotinaldehyde and 3-oxo-3-phenylpropanenitrile as starting materials, and its crystal structure was determined by single-crystal X-ray diffraction for the first time. The crystal belongs to the triclinic system, space group P1 with a = 8.5833（8）, b = 11.9168（12）, c = 14.4424（14） ？, α = 84.208（3）o, β = 88.427（3）o, γ = 73.704（3）o, V = 1410.7（2） ？3, Z = 2, F（000） = 480, μ = 0.064 mm–1, S = 0.966, the final R = 0.0484 and wR = 0.1388 for 5041 observed reflections with I 〉 2s（I） and 316 variable parameters. The preliminary biological tests show that the title compound has a good antitumor activity against K562 in vitro.展开更多
An eco-friendly and economical route for the oxidation of 5-hydroxymethylfurfural(HMF) to 2,5-furandicarboxylic acid(FDCA) with atmospheric dioxygen as the sole oxidant under acid-,base-,metal-,and external initiator-...An eco-friendly and economical route for the oxidation of 5-hydroxymethylfurfural(HMF) to 2,5-furandicarboxylic acid(FDCA) with atmospheric dioxygen as the sole oxidant under acid-,base-,metal-,and external initiator-free conditions in minimal solvent was reported.In the present reaction,the 1,2-diethoxyethylane has a dual role:reaction medium and free-radical initiato r.The FDCA easily crystallizes during the reaction and was simple purified via recrystallization to provide the pure FDCA.展开更多
Immunoglobulin Y(Ig Y)is an effective orally administered antibody used to protect against various intestinal pathogens,but which cannot tolerate the acidic gastric environment.In this study,Ig Y was microencapsulated...Immunoglobulin Y(Ig Y)is an effective orally administered antibody used to protect against various intestinal pathogens,but which cannot tolerate the acidic gastric environment.In this study,Ig Y was microencapsulated by alginate(ALG)and coated with chitooligosaccharide(COS).A response surface methodology was used to optimize the formulation,and a simulated gastrointestinal(GI)digestion(SGID)system to evaluate the controlled release of microencapsulated Ig Y.The microcapsule formulation was optimized as an ALG concentration of 1.56%(15.6 g/L),COS level of 0.61%(6.1 g/L),and Ig Y/ALG ratio of 62.44%(mass ratio).The microcapsules prepared following this formulation had an encapsulation efficiency of 65.19%,a loading capacity of 33.75%,and an average particle size of 588.75μm.Under this optimum formulation,the coating of COS provided a less porous and more continuous microstructure by filling the cracks on the surface,and thus the GI release rate of encapsulated Ig Y was significantly reduced.The release of encapsulated Ig Y during simulated gastric and intestinal digestion well fitted the zero-order and first-order kinetics functions,respectively.The microcapsule also allowed the Ig Y to retain 84.37%immune-activity after 4 h simulated GI digestion,significantly higher than that for unprotected Ig Y(5.33%).This approach could provide an efficient way to preserve Ig Y and improve its performance in the GI tract.展开更多
Two macrocyclic zinc（Ⅱ） complexes {[ZnL（VO3）2]·0.33H2O}n（1） and [ZnL（H2O）2][Ni（CN）4]（2）（L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane） have been obtained from the reactions of [Z...Two macrocyclic zinc（Ⅱ） complexes {[ZnL（VO3）2]·0.33H2O}n（1） and [ZnL（H2O）2][Ni（CN）4]（2）（L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane） have been obtained from the reactions of [ZnL]（ClO4）2 with NH4VO3 and K2[Ni（CN）4], respectively, and structurally characterized by elemental analysis, IR, XRPD, TG and X-ray diffraction. Single-crystal X-ray diffraction analyses indicated that the Zn（Ⅱ） atom lies on an inversion center and is octahedrally coordinated by four nitrogen atoms of the tetradentate macrocyclic ligand in the equatorial plane and two oxygen atoms of [VO4] tetrahedra in the axial positions in 1, and two oxygen atoms of two water molecules in 2. Complex 1 shows a three-dimensional structure, which is constructed by the links of [VO3]nn- chains with [ZnL]2＋, forming one-dimensional channels occupied by vip water molecules. The monomers of [ZnL（H2O）2]2＋ and [Ni（CN）4]2- are connected through the intermolecular hydrogen bonds to form a two-dimensional sheet in complex 2.展开更多
A novel and efficient Ir-catalyzed 1,4-and 1,2-addition of diphenylphosphine oxide to quinolines was developed to obtain various 1,2,3,4-tetrahydroquinoline-2,4-diyl（bisdiphenylphosphine oxide） derivatives. The stru...A novel and efficient Ir-catalyzed 1,4-and 1,2-addition of diphenylphosphine oxide to quinolines was developed to obtain various 1,2,3,4-tetrahydroquinoline-2,4-diyl（bisdiphenylphosphine oxide） derivatives. The structures of these derivatives were characterized by H-RMS and NMR analysis. X-ray crystallography showed that 3 a is in a monoclinic system, space group of P21/c with a = 13.0464（16）, b = 12.6244（16）, c = 20.210（3） ?, β = 105.215（2）o, V =3211.9（7） ?3, Z = 4, F（000） = 1352, μ = 0.42 mm–1, S = 1.07, the final R = 0.059 and wR = 0.195.The in vitro antitumor activities of target compounds were evaluated by MTT assay against human cancer K562, HL-60, HeLa and BGC-823. The target compounds demonstrated weak or moderate antitumor activity against these cell lines.展开更多
The reactions of the four-coordinated macrocyclic copper complex [CuL]（ClO4）2（L = 1,4,8,11-tetraazacyclotetradecane） with NH4VO3 under different conditions gave three inorganic-organic hybrid materials of [CuL][VO...The reactions of the four-coordinated macrocyclic copper complex [CuL]（ClO4）2（L = 1,4,8,11-tetraazacyclotetradecane） with NH4VO3 under different conditions gave three inorganic-organic hybrid materials of [CuL][VO3]2·2.33H2O（1）, [CuL]3[V（10）O（28）]·8H2O（2） and [Cu L]3[V6O（18）]·8H2O（3）. Single-crystal X-ray diffraction analyses reveal that three diverse vanadium polyoxoanions, [V6O（18）]6- ring, [V（10）O（28）]6- cluster, and [V（12）O（35）]^10- ring, were isolated from the same reactant NH4VO3 under different conditions. The [CuL]^2＋ bridges the [V10O28]6- clusters to form a two-dimensional sheet in 2, and link the [V6O（18）]^6- rings in 1 and [V（12）O（35）]^10- rings in 3 into three-dimensional frameworks, respectively.展开更多
The title compound 2-（4-chlorophenyl）-1,3-dimethyl-2,3-dihydro-1H-perimidine（C（19）H（17）ClN2） was synthesized and characterized by elemental analysis, ^1H NMR, HRMS and single-crystal X-ray diffraction. The cry...The title compound 2-（4-chlorophenyl）-1,3-dimethyl-2,3-dihydro-1H-perimidine（C（19）H（17）ClN2） was synthesized and characterized by elemental analysis, ^1H NMR, HRMS and single-crystal X-ray diffraction. The crystal of the title compound belongs to orthorhombic system,space group Pnma with a = 11.385（2）, b = 12.170（2）, c = 11.210（2）A, V = 1553.2（5）A^3, Z = 4, Dc =1.321 g/cm^3, m（Mo-Ka） = 0.244 mm^-1, F（000） = 648, S = 1.309, R = 0.0400 and w R（I 〉 2s（I）） =0.1065. X-ray diffraction results showed that the molecular structure is highly symmetric and the new-formed N-heterocyclic ring is non-planar. In addition, the biological experiment showed that the title compound showed inhibitory activities against fungi with varied potencies.展开更多
In order to meet the reflectivity measurement requirements of any incident angle at different points of the large size special high mirror,a rotating cavity ring-down spectroscopy high reflectivity measurement system ...In order to meet the reflectivity measurement requirements of any incident angle at different points of the large size special high mirror,a rotating cavity ring-down spectroscopy high reflectivity measurement system was built,in which the rotation function of the resonant cavity was set,and the lifting and parallel travelling mechanism of the measured mirror was added.Furthermore,the uncertainty of the measurement results was analyzed and calculated.The results showed that the reflectivity of a high reflective mirror measured by the system was 99.9795%,the measurement accuracy reached the order of 10-6,and the combined standard uncertainty of reflectivity measurement was 0.0028%.Collectively,these results provide a detection guarantee for the maintenance of the large size special high mirror,and provide ideas and methods for the uncertainty analysis of measurement results of similar equipment parameters.展开更多
Terahertz(THz) pulse imaging can be used for biomedicine, material, and food security. However, image quality is lower attributed to the THz time-domain spectroscopy system. Such as, noises and lower space resolution ...Terahertz(THz) pulse imaging can be used for biomedicine, material, and food security. However, image quality is lower attributed to the THz time-domain spectroscopy system. Such as, noises and lower space resolution are presented in some THz images. To improve the THz image quality, we proposed a novel method which combining the simulation evolutionary with the symmetric fourth order partial differential equation. The image edge is first detected by using the simulation evolutionary. Then the symmetric fourth order partial differential equation(PDE) is applied on the non-edge image for noise reduction. Finally, the de-noise image is combined with the edge image obtained from the edge detection step. Experiments on four different THz images prove that the proposed method can preserve the edge information during noise reduction.展开更多
Three new o-hydroxy Schiff bases, L1, L2 and L3, were derived from the 1：1 M condensation of substituted salicylaldehyde with tris base and were characterized by FT-IR, ^1H NMR and ^13C NMR spectroscopies. The crysta...Three new o-hydroxy Schiff bases, L1, L2 and L3, were derived from the 1：1 M condensation of substituted salicylaldehyde with tris base and were characterized by FT-IR, ^1H NMR and ^13C NMR spectroscopies. The crystal structure of L1 was also determined by single-crystal X-ray analysis, and it exists as a zwitterionic form in the solid state, with the H atom of the phenol group being transferred to the imine N atom. It adopts an E-configuration about the central C=N double bond. In addition, the biological activity assay was carried out and the results show that the Schiff-base compounds have a diverse range of biological activities against the fungi tested, which suggests great potential applications in antifungal fields in the future.展开更多
In this paper, we consider a fully discrete finite element approximation for time fractional optimal control problems. The state and adjoint state are approximated by triangular linear fi nite elements in space and &l...In this paper, we consider a fully discrete finite element approximation for time fractional optimal control problems. The state and adjoint state are approximated by triangular linear fi nite elements in space and <em>L</em>1 scheme in time. The control is obtained by the variational discretization technique. The main purpose of this work is to derive the convergence and superconvergence. A numerical example is presented to validate our theoretical results.展开更多
Benzene is a volatile organic compound that can seriously harm human health,while it can serve as a precursor to produce chemicals of more complex structures in chemical industry.Capturing benzene using adsorbents is ...Benzene is a volatile organic compound that can seriously harm human health,while it can serve as a precursor to produce chemicals of more complex structures in chemical industry.Capturing benzene using adsorbents is of great importance for human health,when the separation of hydrocarbons including benzene from crude oil was referred to as one of the“seven chemical separations to change the world”.In this work,we reported the efficient and selective separation of benzene from BTX and cyclohexane by hydrogen bonding self-assembly nonporous adaptive crystals AdaOH for the first time under mild and user-friendly conditions.Separation of benzene and cyclohexane(v/v=1:1)can be achieved by AdaOH with a purity of benzene up to 96.8%.Separation of BTX(v/v;benzene:toluene:o-xylene:m-xylene:pxylene=1:1:1:1:1)can be achieved by AdaOH with a purity of benzene increased from 20%to 82.9%.Our results suggest that separation of benzene using the activated AdaOH as a non-porous adaptive crystal for selectively and efficiently capturing benzene can solve the challenge in separation of benzene from other chemicals such as cyclohexane in chemical industry,and can be helpful for removal of benzene that is released from the vehicles to air.The advantages of commercially availability,easy preparation,high separation efficiency and selectivity for benzene might endow this material with enormous potential for practical uses in areas like petrochemical industry.展开更多
The title compound, { [Ag2（bipy）2（H2O）2]·pydc·2H2O}n （bipy = 4,4＇-bipyridine, pydc = pyridine-3,5-dicarboxylate）, has been synthesized by the reaction of Ag2O with pydc and bipy in CH3OH solution. It ...The title compound, { [Ag2（bipy）2（H2O）2]·pydc·2H2O}n （bipy = 4,4＇-bipyridine, pydc = pyridine-3,5-dicarboxylate）, has been synthesized by the reaction of Ag2O with pydc and bipy in CH3OH solution. It crystallizes in the monoclinic system, space group C2/c with a = 21.419（8）, b = 7.515（3）, c = 18.070（7） A,β = 108.273（6）°, Mr = 765.27, V = 2761.9（17） A^3, Z = 4, Dc = 1.840 g/cm^3, F（000） = 1528,μ = 1.478 mm^-1, the final R = 0.0307 and wR = 0.0681. The structure determined demonstrated that the Ag（I） is three-coordinated by two nitrogen atoms from bipy and one water molecule, forming a one-dimensional coordination polymer [Ag2（bipy）2（H2O）2]n^2n＋, which is further linked to generate a two-dimensional layer structure via Ag---Ag attractions.展开更多
Two complexes with formulas [Ni L][（Ni L）（IPA）2]·8H2O（1） and [（Ni L）（H2O）2] [（Ni L）（PMA）]·4H2O（2）（L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane,IPA2– = isophthalic anion,P...Two complexes with formulas [Ni L][（Ni L）（IPA）2]·8H2O（1） and [（Ni L）（H2O）2] [（Ni L）（PMA）]·4H2O（2）（L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane,IPA2– = isophthalic anion,PMA4– = 1,2,4,5-benzenetetracarboxylic anion） were synthesized and characterized by elemental analyses and IR spectra.The crystal structures were determined by X-ray diffraction.In complex 1,the [Ni L]^2＋ bridged IPA^2– to give [（Ni L）（IPA）2]^2– monomer,and the [Ni L]^2＋ bridged PMA4– to form a one-dimensional chain [（Ni L）（PMA）]n^2n– in complex 2.The [Ni L]^2＋ and [（Ni L）（IPA）2]^2–/[（Ni L）（PMA）]^2– are connected through intermolecular hydrogen bonding to generate three-dimensional supramolecular structures.展开更多
A novel complex of [NiL（OOCNH2C2H3SClO3）]·H2O was obtained unexpectedly by the reaction of [Ni（rac-L）]（ClO4）2 with l-cysteine （L=5,5,7,12,12,14-hexamethyl-1,4,8,11-tetra- azacyclotetradecane）, and charact...A novel complex of [NiL（OOCNH2C2H3SClO3）]·H2O was obtained unexpectedly by the reaction of [Ni（rac-L）]（ClO4）2 with l-cysteine （L=5,5,7,12,12,14-hexamethyl-1,4,8,11-tetra- azacyclotetradecane）, and characterized by EA, IR, ESI-MS and single-crystal X-ray diffraction. It crystallizes in the orthorhombic system, space group P212121 with a=9.211（12）, b=14.942（19）, c=19.002（2）, Mr=563.80, V=2615.3（6）3 , Z=4, Dc=1.432 g/cm3 , F（000）=1204, μ=0.966 mm-1 , the final R=0.0565 and wR=0.1515. The central nickel（Ⅱ） ion displays a distorted six-coordinate octahedral coordination geometry by coordination with four nitrogen atoms of L, and one oxygen and one nitrogen atoms of l-cysteine. The sulfur atom of l-cysteine instead of oxygen atom links directly with the chlorine atom of perchlorate. The title complex is the first example of perchlorate salt involving the sulfur atom.展开更多
To improve the prediction accuracy of the International Roughness Index(IRI)of Jointed PlainConcrete Pavements(JPCP)and Continuously Reinforced Concrete Pavements(CRCP),a machine learning approach is developed in this...To improve the prediction accuracy of the International Roughness Index(IRI)of Jointed PlainConcrete Pavements(JPCP)and Continuously Reinforced Concrete Pavements(CRCP),a machine learning approach is developed in this study for the modelling,combining an improved Beetle Antennae Search(MBAS)algorithm and Random Forest(RF)model.The 10-fold cross-validation was applied to verify the reliability and accuracy of the model proposed in this study.The importance scores of all input variables on the IRI of JPCP and CRCP were analysed as well.The results by the comparative analysis showed the prediction accuracy of the IRI of the newly developed MBAS and RF hybrid machine learning model(RF-MBAS)in this study is higher,indicated by the RMSE and R values of 0.2732 and 0.9476 for the JPCP as well as the RMSE and R values of 0.1863 and 0.9182 for the CRCP.The accuracy of this obtained result far exceeds that of the IRI prediction model used in the traditional Mechanistic-Empirical Pavement Design Guide(MEPDG),indicating the great potential of this developed model.The importance analysis showed that the IRI of JPCP and CRCP was proportional to the corresponding input variables in this study,including the total joint faulting cumulated per KM(TFAULT),percent subgrade material passing the 0.075-mm Sieve(P_(200))and pavement surface area with flexible and rigid patching(all Severities)(PATCH)which scored higher.展开更多
The title compound N-(2-(2-hydroxy-2-phenylacetyl)phenyl)cinnamamide(C23H19NO3,Mr=357.39)has been synthesized with 2-iodoaniline and ethynylbenzene as starting materials,and its crystal structure was determined by ^1H...The title compound N-(2-(2-hydroxy-2-phenylacetyl)phenyl)cinnamamide(C23H19NO3,Mr=357.39)has been synthesized with 2-iodoaniline and ethynylbenzene as starting materials,and its crystal structure was determined by ^1H NMR,^13C NMR,H RMS and single-crystal X-ray diffraction for the first time.The crystal crystallizes in monoclinic system,space group P21/c with a=8.2850(7),b=25.934(2),c=8.3032(6)A,β=95.314(7)°,V=1776.4(3)A^3,Z=4,T=293(2)K,μ(Cu Kα)=0.71 mm^-1,Dc=1.336 Mg/cm3,3019 reflections measured(6.832≤2θ≤129.982°),2996 unique(Rint=0.0463,Rsigma=0.0549)which were used in all calculations.The final R=0.0880(I>2σ(I))and wR=0.2447(all data).The target compound has demonstrated weak or moderate anti-tumor activity against human leukemia k562 cell,human promyelocytic leukemia HL-60 cell,human gastric cancer line BGC-823,Hela cell and lung cancer A549 cell.展开更多
基金Under the auspices of the National Natural Science Foundation of China(No.42101342,U2243205)the Third Comprehensive Scientific Expedition to Xinjiang(No.2021XJKK1403)。
文摘Cotton is an important global cash crops that serve as the primary source of natural fiber for textiles.A thorough understand-ing of the long-term variations in cotton cultivation is vital for optimizing cotton cultivation management and promoting the sustainable development of the cotton industry.Xinjiang is the primary cotton-producing region in China.However,long-term data of cotton cultiv-ation areas with high spatial resolution are unavailable for Xinjiang,China.Therefore,this study aimed to identify and map an accurate 30-m cotton cultivation area dataset in Xinjiang from 2000 to 2020 by applying a Random Forest(RF)-based method that integrates Landsat and Moderate Resolution Imaging Spectroradiometer(MODIS)images,and validated the applicability and accuracy of dataset at a large spatial scale.Then,this study analyzed the spatiotemporal variations and influencing factors of cotton cultivation in the study period.The results showed that a high classification accuracy was achieved(overall accuracy>85%,F1>0.80),strongly agreeing with county-level agricultural statistical yearbook data(R2>0.72).Significant spatiotemporal variation in the cotton cultivation areas was found in Xinjiang,with a total increase of 1131.26 kha from 2000 to 2020.Notably,cotton cultivation area in southern Xinjiang expan-ded substantially,with that in Aksu increasing from 20.10%in 2000 to 28.17%in 2020,representing an expansion of 374.29 kha.In northern Xinjiang,the cotton areas in the Tacheng region also exhibited significant increased by almost ten percentage points in the same period.In contrast,cotton cultivation in eastern Xinjiang declined,decreasing from 2.22%in 2000 to merely 0.24%in 2020.Standard deviation ellipse analysis revealed a‘northeast-southwest’spatial distribution,with the centroid consistently located in Aksu and shifting 102.96 km over the 20-yr period.Pearson correlation analysis indicated that socioeconomic factors had a stronger influence on cotton cultivation than climatic factors,with effective irrigation area(r=0.963,P<0.05)and total agricultural machinery power(r=0.823)showing significant positive correlations,whereas climatic variables exhibiting weak associations(r<0.200).These results provide valuable scientific data for informed agricultural management,sustainable development,and policymaking.
文摘Objectives:Adults with cataracts are often reported with mental health issues,which has driven researchers to identify modifiable factors so that effective intervention programs can be timely implemented.Thus,we investigated associations of physical activity(PA)and sedentary behavior(SB)with stress,anxiety,and sleep problems among adultswith cataracts.Methods:In this cross-sectional study,a total of 2219 participantswith cataracts completed self-reported measures on demographic characteristics(e.g.,age and sex),PA,SB,anxiety,stress and sleep problems.Multiple linear regression and logistic analyses adjusted for covariates were employed to examine the associations of PA and SB with outcomes of interest.Results:Meeting PA recommendation was significantly associated with lower stress score(β=−2.920,95%CI:−3.880 to−1.959;p<0.001),a 51.2%reduction in the odds of sleep problems(OR=0.488,95%CI:0.389 to 0.612;p<0.001).Limiting SB to≤8 h/day was significantly associated with reduced stress score(−5.191,95%CI:−6.378 to−4.004;p<0.001),lower odds of anxiety symptoms(OR=0.481,95%CI:0.354 to 0.655;p<0.001),and sleep problems(OR=0.540,95%CI:0.420 to 0.693;p<0.001).The greatest benefit appeared when both PA and SB recommendations were achieved simultaneously.Compared with individuals who met neither recommendation,those who were sufficiently active and sat less than 8 h/day showed a 9.307-point lower stress score(95%CI:−11.12 to−7.49;p<0.001),a 54.9%lower odds of anxiety symptoms(OR=0.451,95%CI:0.262 to 0.776;p=0.004),and a 66.4%lower odds of sleep problems(OR=0.336,95%CI:0.206 to 0.550;p<0.001).Conclusions:Meeting PA and SB recommendations could provide substantial psychosocial benefits for adults with cataracts.
基金supported by the Science and Technology Planning Project of Hunan Province (2012FJ3050, 2012NK3067)the Construct Program of the Key Discipline in Hunan Province (2011–76)the Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province (2012–318)
文摘The title compound, [NiL]5[V34O82·8H2O （1, L=5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane）, has been synthesized under hydrothermal conditions and structurally characterized by EA, IR, XPS, TG and single-crystal X-ray diffraction. It crystallizes in the monoclinic system, space group C2/c with a=33.061（4）, b=15.3457（17）, c=33.902（4）, β=101.930（2）°, Mr=4904.08, V=16828（3）3 , Z=4, Dc=1.936 g/cm3 , F（000）=9832, μ=2.425 mm-1 , the final R=0.0402 and wR=0.0969. The mixed valence vanadium clusters of [V34O82]10- bridges [NiL]2＋ to form a one-dimensional chain in 1. To the best of our knowledge, the title complex is the first example of organic-inorganic hybrid material involving the largest vanadium cluster of [V34O82]10-.
基金supported by the Natural Science Foundation of Hunan Province(No.2018JJ3196)the opening project of key laboratory of comprehensive utilization of advantage plants resources in Hunan south,Hunan university of science and engineering(No.XNZW17C04,XNZW17C05)aid program for science and technology innovative research team in higher educational institutions of Hunan province(No.2012-318)
文摘The title compound（14 S）-2,14-diphenyl-6,6 a,11,12-tetrahydro-5 H,10 H,14 H-[1,8] naphthyridino[1,2-c]pyrido[3,2,1-ij]quinazoline-3-carbonitrile（C31 H26 N4, Mr = 454.56） has been synthesized with 2-aminonicotinaldehyde and 3-oxo-3-phenylpropanenitrile as starting materials, and its crystal structure was determined by single-crystal X-ray diffraction for the first time. The crystal belongs to the triclinic system, space group P1 with a = 8.5833（8）, b = 11.9168（12）, c = 14.4424（14） ？, α = 84.208（3）o, β = 88.427（3）o, γ = 73.704（3）o, V = 1410.7（2） ？3, Z = 2, F（000） = 480, μ = 0.064 mm–1, S = 0.966, the final R = 0.0484 and wR = 0.1388 for 5041 observed reflections with I 〉 2s（I） and 316 variable parameters. The preliminary biological tests show that the title compound has a good antitumor activity against K562 in vitro.
基金financial support from the Hunan Provincial Natural Science Foundation of China (Nos.2019JJ40090 and 2019JJ20008)
文摘An eco-friendly and economical route for the oxidation of 5-hydroxymethylfurfural(HMF) to 2,5-furandicarboxylic acid(FDCA) with atmospheric dioxygen as the sole oxidant under acid-,base-,metal-,and external initiator-free conditions in minimal solvent was reported.In the present reaction,the 1,2-diethoxyethylane has a dual role:reaction medium and free-radical initiato r.The FDCA easily crystallizes during the reaction and was simple purified via recrystallization to provide the pure FDCA.
基金Project supported by the National Key Research and Development Program of China(No.2018YFD0400305)the Modern Agro-industry Technology Research System of China(No.CARS-40-K26)the“One Belt and One Road”International Science and Technology Cooperation Program of Zhejiang,China(No.2019C04022)。
文摘Immunoglobulin Y(Ig Y)is an effective orally administered antibody used to protect against various intestinal pathogens,but which cannot tolerate the acidic gastric environment.In this study,Ig Y was microencapsulated by alginate(ALG)and coated with chitooligosaccharide(COS).A response surface methodology was used to optimize the formulation,and a simulated gastrointestinal(GI)digestion(SGID)system to evaluate the controlled release of microencapsulated Ig Y.The microcapsule formulation was optimized as an ALG concentration of 1.56%(15.6 g/L),COS level of 0.61%(6.1 g/L),and Ig Y/ALG ratio of 62.44%(mass ratio).The microcapsules prepared following this formulation had an encapsulation efficiency of 65.19%,a loading capacity of 33.75%,and an average particle size of 588.75μm.Under this optimum formulation,the coating of COS provided a less porous and more continuous microstructure by filling the cracks on the surface,and thus the GI release rate of encapsulated Ig Y was significantly reduced.The release of encapsulated Ig Y during simulated gastric and intestinal digestion well fitted the zero-order and first-order kinetics functions,respectively.The microcapsule also allowed the Ig Y to retain 84.37%immune-activity after 4 h simulated GI digestion,significantly higher than that for unprotected Ig Y(5.33%).This approach could provide an efficient way to preserve Ig Y and improve its performance in the GI tract.
基金supported by the Project for Undergraduate Research Study and Innovative Experiment of Hunan Provincial(2013-191)National Undergraduate Training Programs for Innovation and Entrepreneurship(201310551158)+4 种基金the Scientific Research Fund of Hunan Provincial Education Department(13B029,13A030)the Key Laboratory of Functional Organometallic Materials of Hunan Province College(13K09,13K10)the Program for Excellent Talents in Hunan University of Science and Engineeringthe Construct Program of the Key Discipline in Hunan Province(2011-76)the Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province(2012-318)
文摘Two macrocyclic zinc（Ⅱ） complexes {[ZnL（VO3）2]·0.33H2O}n（1） and [ZnL（H2O）2][Ni（CN）4]（2）（L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane） have been obtained from the reactions of [ZnL]（ClO4）2 with NH4VO3 and K2[Ni（CN）4], respectively, and structurally characterized by elemental analysis, IR, XRPD, TG and X-ray diffraction. Single-crystal X-ray diffraction analyses indicated that the Zn（Ⅱ） atom lies on an inversion center and is octahedrally coordinated by four nitrogen atoms of the tetradentate macrocyclic ligand in the equatorial plane and two oxygen atoms of [VO4] tetrahedra in the axial positions in 1, and two oxygen atoms of two water molecules in 2. Complex 1 shows a three-dimensional structure, which is constructed by the links of [VO3]nn- chains with [ZnL]2＋, forming one-dimensional channels occupied by vip water molecules. The monomers of [ZnL（H2O）2]2＋ and [Ni（CN）4]2- are connected through the intermolecular hydrogen bonds to form a two-dimensional sheet in complex 2.
基金Supported by the foundation of the Department of Education of Guangdong Province(2016KTSCX144,2017KZDXM085)Natural Science Foundation of Hunan Province(No.2018JJ3196)the High-level Scientific Research Foundation for the introduction of talent(AL2018008)
文摘A novel and efficient Ir-catalyzed 1,4-and 1,2-addition of diphenylphosphine oxide to quinolines was developed to obtain various 1,2,3,4-tetrahydroquinoline-2,4-diyl（bisdiphenylphosphine oxide） derivatives. The structures of these derivatives were characterized by H-RMS and NMR analysis. X-ray crystallography showed that 3 a is in a monoclinic system, space group of P21/c with a = 13.0464（16）, b = 12.6244（16）, c = 20.210（3） ?, β = 105.215（2）o, V =3211.9（7） ?3, Z = 4, F（000） = 1352, μ = 0.42 mm–1, S = 1.07, the final R = 0.059 and wR = 0.195.The in vitro antitumor activities of target compounds were evaluated by MTT assay against human cancer K562, HL-60, HeLa and BGC-823. The target compounds demonstrated weak or moderate antitumor activity against these cell lines.
基金Supported by the Opening Project of Key Laboratory of Comprehensive Utilization of Advantage Plants Resources in Hunan South(XNZW14C08)the NSF of Hunan Province(2015JJ2072)+2 种基金the Construct Program of the Key Discipline in Hunan Provincethe Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Provincethe Project for Undergraduate Research Study and Innovative Experiment of Hunan Provincial(2016-283)
文摘The reactions of the four-coordinated macrocyclic copper complex [CuL]（ClO4）2（L = 1,4,8,11-tetraazacyclotetradecane） with NH4VO3 under different conditions gave three inorganic-organic hybrid materials of [CuL][VO3]2·2.33H2O（1）, [CuL]3[V（10）O（28）]·8H2O（2） and [Cu L]3[V6O（18）]·8H2O（3）. Single-crystal X-ray diffraction analyses reveal that three diverse vanadium polyoxoanions, [V6O（18）]6- ring, [V（10）O（28）]6- cluster, and [V（12）O（35）]^10- ring, were isolated from the same reactant NH4VO3 under different conditions. The [CuL]^2＋ bridges the [V10O28]6- clusters to form a two-dimensional sheet in 2, and link the [V6O（18）]^6- rings in 1 and [V（12）O（35）]^10- rings in 3 into three-dimensional frameworks, respectively.
基金financially supported by the Science and Technology Planning Project of Hunan Province2015GK3037)the Scientific Research Fund of Hunan Provincial Education Department(14A058,13A030)
文摘The title compound 2-（4-chlorophenyl）-1,3-dimethyl-2,3-dihydro-1H-perimidine（C（19）H（17）ClN2） was synthesized and characterized by elemental analysis, ^1H NMR, HRMS and single-crystal X-ray diffraction. The crystal of the title compound belongs to orthorhombic system,space group Pnma with a = 11.385（2）, b = 12.170（2）, c = 11.210（2）A, V = 1553.2（5）A^3, Z = 4, Dc =1.321 g/cm^3, m（Mo-Ka） = 0.244 mm^-1, F（000） = 648, S = 1.309, R = 0.0400 and w R（I 〉 2s（I）） =0.1065. X-ray diffraction results showed that the molecular structure is highly symmetric and the new-formed N-heterocyclic ring is non-planar. In addition, the biological experiment showed that the title compound showed inhibitory activities against fungi with varied potencies.
基金supported by the 2021 Annual Instructional Science and Technology Program of Yongzhou(No.2021-YZKJZD-009)the Outstanding Youth Foundation of Hunan Province(No.2020JJ2015)the Science Research Project of Hunan Institute of Science and Technology(No.21xky040).
文摘In order to meet the reflectivity measurement requirements of any incident angle at different points of the large size special high mirror,a rotating cavity ring-down spectroscopy high reflectivity measurement system was built,in which the rotation function of the resonant cavity was set,and the lifting and parallel travelling mechanism of the measured mirror was added.Furthermore,the uncertainty of the measurement results was analyzed and calculated.The results showed that the reflectivity of a high reflective mirror measured by the system was 99.9795%,the measurement accuracy reached the order of 10-6,and the combined standard uncertainty of reflectivity measurement was 0.0028%.Collectively,these results provide a detection guarantee for the maintenance of the large size special high mirror,and provide ideas and methods for the uncertainty analysis of measurement results of similar equipment parameters.
基金This work has been supported by the Hunan Provincial Natural Science Foundation Program(No.2020JJ4327)the Department of Education Science Research General Project in Hunan Province(No.18C1063)+2 种基金the Featured Application Discipline in Hunan University of Science and Engineering(Computer Science and Technology)the Scientific Research Projects in Colleges and Universities(No.2019KTSCX165)the Shaoguan Science and Technology Department Project(No.2019sn066)。
文摘Terahertz(THz) pulse imaging can be used for biomedicine, material, and food security. However, image quality is lower attributed to the THz time-domain spectroscopy system. Such as, noises and lower space resolution are presented in some THz images. To improve the THz image quality, we proposed a novel method which combining the simulation evolutionary with the symmetric fourth order partial differential equation. The image edge is first detected by using the simulation evolutionary. Then the symmetric fourth order partial differential equation(PDE) is applied on the non-edge image for noise reduction. Finally, the de-noise image is combined with the edge image obtained from the edge detection step. Experiments on four different THz images prove that the proposed method can preserve the edge information during noise reduction.
基金financially supported by the Natural Science Foundation of Hunan Province(2017JJ3093)the Scientific Research Fund of Hunan Provincial Education Department(No.16B104)
文摘Three new o-hydroxy Schiff bases, L1, L2 and L3, were derived from the 1：1 M condensation of substituted salicylaldehyde with tris base and were characterized by FT-IR, ^1H NMR and ^13C NMR spectroscopies. The crystal structure of L1 was also determined by single-crystal X-ray analysis, and it exists as a zwitterionic form in the solid state, with the H atom of the phenol group being transferred to the imine N atom. It adopts an E-configuration about the central C=N double bond. In addition, the biological activity assay was carried out and the results show that the Schiff-base compounds have a diverse range of biological activities against the fungi tested, which suggests great potential applications in antifungal fields in the future.
文摘In this paper, we consider a fully discrete finite element approximation for time fractional optimal control problems. The state and adjoint state are approximated by triangular linear fi nite elements in space and <em>L</em>1 scheme in time. The control is obtained by the variational discretization technique. The main purpose of this work is to derive the convergence and superconvergence. A numerical example is presented to validate our theoretical results.
基金the financial support from the National Natural Science Foundation of China(No.21602055)Natural Science Foundation of Hunan Province(No.2017JJ3094).
文摘Benzene is a volatile organic compound that can seriously harm human health,while it can serve as a precursor to produce chemicals of more complex structures in chemical industry.Capturing benzene using adsorbents is of great importance for human health,when the separation of hydrocarbons including benzene from crude oil was referred to as one of the“seven chemical separations to change the world”.In this work,we reported the efficient and selective separation of benzene from BTX and cyclohexane by hydrogen bonding self-assembly nonporous adaptive crystals AdaOH for the first time under mild and user-friendly conditions.Separation of benzene and cyclohexane(v/v=1:1)can be achieved by AdaOH with a purity of benzene up to 96.8%.Separation of BTX(v/v;benzene:toluene:o-xylene:m-xylene:pxylene=1:1:1:1:1)can be achieved by AdaOH with a purity of benzene increased from 20%to 82.9%.Our results suggest that separation of benzene using the activated AdaOH as a non-porous adaptive crystal for selectively and efficiently capturing benzene can solve the challenge in separation of benzene from other chemicals such as cyclohexane in chemical industry,and can be helpful for removal of benzene that is released from the vehicles to air.The advantages of commercially availability,easy preparation,high separation efficiency and selectivity for benzene might endow this material with enormous potential for practical uses in areas like petrochemical industry.
基金the Construct Program of the Key Discipline in Hunan Province (No. 2006-180)the Key Scientific Research Project of Hunan Provincial Education Department (No. 07A023)
文摘The title compound, { [Ag2（bipy）2（H2O）2]·pydc·2H2O}n （bipy = 4,4＇-bipyridine, pydc = pyridine-3,5-dicarboxylate）, has been synthesized by the reaction of Ag2O with pydc and bipy in CH3OH solution. It crystallizes in the monoclinic system, space group C2/c with a = 21.419（8）, b = 7.515（3）, c = 18.070（7） A,β = 108.273（6）°, Mr = 765.27, V = 2761.9（17） A^3, Z = 4, Dc = 1.840 g/cm^3, F（000） = 1528,μ = 1.478 mm^-1, the final R = 0.0307 and wR = 0.0681. The structure determined demonstrated that the Ag（I） is three-coordinated by two nitrogen atoms from bipy and one water molecule, forming a one-dimensional coordination polymer [Ag2（bipy）2（H2O）2]n^2n＋, which is further linked to generate a two-dimensional layer structure via Ag---Ag attractions.
基金supported by the Natural Science Foundation of Hunan Province(2015JJ2072)the Key Laboratory of Comprehensive Utilization of Advantage Plants Resources in Hunan South(XNZW14C08)+1 种基金the Construct Program of the Key Discipline in Hunan Province(2011-76)the Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province(2012-318)
文摘Two complexes with formulas [Ni L][（Ni L）（IPA）2]·8H2O（1） and [（Ni L）（H2O）2] [（Ni L）（PMA）]·4H2O（2）（L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane,IPA2– = isophthalic anion,PMA4– = 1,2,4,5-benzenetetracarboxylic anion） were synthesized and characterized by elemental analyses and IR spectra.The crystal structures were determined by X-ray diffraction.In complex 1,the [Ni L]^2＋ bridged IPA^2– to give [（Ni L）（IPA）2]^2– monomer,and the [Ni L]^2＋ bridged PMA4– to form a one-dimensional chain [（Ni L）（PMA）]n^2n– in complex 2.The [Ni L]^2＋ and [（Ni L）（IPA）2]^2–/[（Ni L）（PMA）]^2– are connected through intermolecular hydrogen bonding to generate three-dimensional supramolecular structures.
基金supported by the Science and Technology Planning Project of Hunan Province (2012FJ3050,2012NK3067)the Construct Program of the Key Discipline in Hunan Province (2011–76)the Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province (2012–318)
文摘A novel complex of [NiL（OOCNH2C2H3SClO3）]·H2O was obtained unexpectedly by the reaction of [Ni（rac-L）]（ClO4）2 with l-cysteine （L=5,5,7,12,12,14-hexamethyl-1,4,8,11-tetra- azacyclotetradecane）, and characterized by EA, IR, ESI-MS and single-crystal X-ray diffraction. It crystallizes in the orthorhombic system, space group P212121 with a=9.211（12）, b=14.942（19）, c=19.002（2）, Mr=563.80, V=2615.3（6）3 , Z=4, Dc=1.432 g/cm3 , F（000）=1204, μ=0.966 mm-1 , the final R=0.0565 and wR=0.1515. The central nickel（Ⅱ） ion displays a distorted six-coordinate octahedral coordination geometry by coordination with four nitrogen atoms of L, and one oxygen and one nitrogen atoms of l-cysteine. The sulfur atom of l-cysteine instead of oxygen atom links directly with the chlorine atom of perchlorate. The title complex is the first example of perchlorate salt involving the sulfur atom.
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.2021QN1006)Natural Science Foundation of Hunan(Grant No.2023JJ50418)Hunan Provincial Transportation Technology Project(Grant No.202109).
文摘To improve the prediction accuracy of the International Roughness Index(IRI)of Jointed PlainConcrete Pavements(JPCP)and Continuously Reinforced Concrete Pavements(CRCP),a machine learning approach is developed in this study for the modelling,combining an improved Beetle Antennae Search(MBAS)algorithm and Random Forest(RF)model.The 10-fold cross-validation was applied to verify the reliability and accuracy of the model proposed in this study.The importance scores of all input variables on the IRI of JPCP and CRCP were analysed as well.The results by the comparative analysis showed the prediction accuracy of the IRI of the newly developed MBAS and RF hybrid machine learning model(RF-MBAS)in this study is higher,indicated by the RMSE and R values of 0.2732 and 0.9476 for the JPCP as well as the RMSE and R values of 0.1863 and 0.9182 for the CRCP.The accuracy of this obtained result far exceeds that of the IRI prediction model used in the traditional Mechanistic-Empirical Pavement Design Guide(MEPDG),indicating the great potential of this developed model.The importance analysis showed that the IRI of JPCP and CRCP was proportional to the corresponding input variables in this study,including the total joint faulting cumulated per KM(TFAULT),percent subgrade material passing the 0.075-mm Sieve(P_(200))and pavement surface area with flexible and rigid patching(all Severities)(PATCH)which scored higher.
基金supported by the construct program of applied characteristic discipline in Hunan University of Science and Engineering,Research Learning and Innovative Experimental Program for College Students of Hunan University of Science and Engineering(No.[2018]32-51)the opening project of key laboratory of comprehensive utilization of advantage plants resources in Hunan south,Hunan university of science and engineering(No.XNZW17C04,XNZW17C05)the Planned Science and Technology Project of Hunan Yongzhou,China(No.2018ZD15)
文摘The title compound N-(2-(2-hydroxy-2-phenylacetyl)phenyl)cinnamamide(C23H19NO3,Mr=357.39)has been synthesized with 2-iodoaniline and ethynylbenzene as starting materials,and its crystal structure was determined by ^1H NMR,^13C NMR,H RMS and single-crystal X-ray diffraction for the first time.The crystal crystallizes in monoclinic system,space group P21/c with a=8.2850(7),b=25.934(2),c=8.3032(6)A,β=95.314(7)°,V=1776.4(3)A^3,Z=4,T=293(2)K,μ(Cu Kα)=0.71 mm^-1,Dc=1.336 Mg/cm3,3019 reflections measured(6.832≤2θ≤129.982°),2996 unique(Rint=0.0463,Rsigma=0.0549)which were used in all calculations.The final R=0.0880(I>2σ(I))and wR=0.2447(all data).The target compound has demonstrated weak or moderate anti-tumor activity against human leukemia k562 cell,human promyelocytic leukemia HL-60 cell,human gastric cancer line BGC-823,Hela cell and lung cancer A549 cell.
