Boron is an essential microelement for plant growth.Tomato is one of the most cultivated fruits and vegetables in the world,and boron deficiency severely inhibits its yield and quality.However,the mechanism of tomato ...Boron is an essential microelement for plant growth.Tomato is one of the most cultivated fruits and vegetables in the world,and boron deficiency severely inhibits its yield and quality.However,the mechanism of tomato in response to boron deficiency remains largely unclear.Here,we investigated the physiological and molecular bases of the boron deficiency response in hydroponically grown tomato seedlings.Boron deficiency repressed the expression of genes associated with nitrogen metabolism,while it induced the expression of genes related to the pentose phosphate pathway,thereby altering carbon flow to provide energy for plants to cope with stress.Boron deficiency increased the accumulation of copper,manganese and iron,thereby maintaining chlorophyll content and photosynthetic efficiency at the early stage of stress.In addition,boron deficiency downregulated the expression of genes involved in cell wall organization and reduced the contents of pectin and cellulose in roots,ultimately retarding root growth.Furthermore,boron deficiency markedly altered phytohormone levels and signaling pathways in roots.The contents of jasmonic acid,jasmonoy1-L-isoleucine,trans-zeatin riboside,abscisic acid,salicylic acid,and SA glucoside were decreased;in contrast,the contents of isopentenyladenine riboside and ethylene precursor 1-aminocyclopropane-1-carboxylic acid were increased in the roots of boron-deficient tomato plants.These results collectively indicate that tomato roots reprogram carbon/nitrogen metabolism,alter cell wall components and modulate phytohormone pathways to survive boron deficiency.This study provides a theoretical basis for further elucidating the adaptive mechanism of tomato in response to boron deficiency.展开更多
The aim of this paper is to given an algebraic computational method for finding maximal independent sets as well as the independent number of an arbitrary finite graph of n vertices G by strengthening the problem of f...The aim of this paper is to given an algebraic computational method for finding maximal independent sets as well as the independent number of an arbitrary finite graph of n vertices G by strengthening the problem of finding maximal independent sets of G to the problem of finding k-independent sets in G for. It is shown that the existence of k-independent sets in G is equivalent to the existence of solutions of a system of multivariate polynomial equations. It follows that the problem of finding k-independent sets can be realized by using Gröbner bases of polynomial ideals. Since the number of k-independent sets is finite, the triangular equations composed by Gröbner bases are easier to be solved. Consequently, the maximal independent sets and the independent number of G are obtained after solving at most n such equations. Finally, the numerical example is presented to illustrate the effectiveness of this algebraic computational method.展开更多
Under the background of emerging agricultural education,practice bases are an important place to train profession talented person that match social needs,so it is very important to build stable and long-term practice ...Under the background of emerging agricultural education,practice bases are an important place to train profession talented person that match social needs,so it is very important to build stable and long-term practice bases.At present,the main problems in the construction of practice bases for postgraduates in local colleges and universities are mainly focusing on construction and neglecting management,imperfect cooperation mechanism and lack of teaching management effectively.It is of great significance to build a long-term management mechanism to ensure the education quality of practice bases.Therefore,constructing the mode of"double integration and double promotion of production and education"with practice bases as the carrier and realizing the organic combination of industrial needs and postgraduate projects is an important idea for local colleges and universities to train professional degree postgraduates to"know agriculture,love agriculture,strengthen agriculture and promote agriculture",and it also provides a reference for the mechanism construction of postgraduate bases.展开更多
The compounds have been synthesized and characterized by routine MS, IR and NMR spectrometry methods. The compounds are all active on bacterial strains with the exception of Salmonella typhimirium, with a MIC value of...The compounds have been synthesized and characterized by routine MS, IR and NMR spectrometry methods. The compounds are all active on bacterial strains with the exception of Salmonella typhimirium, with a MIC value of 7.5 mg/mL. They show a percentage of anti-radical activity of 75.476 ± 5.070 for the compound DAN-S and of 68.142 ± 6.539 for the compound DAN-OV. The compounds are sensitive to the two champions used. DAN-S compound is then the most active.展开更多
A previous study was conducted on the synthesis and antibacterial evaluation of Mannich bases of 2-(thioalkyl)-1H-methylbenzimidazole derivatives. The results of this study showed that certain 2-(thioalkyl)-1H-methylb...A previous study was conducted on the synthesis and antibacterial evaluation of Mannich bases of 2-(thioalkyl)-1H-methylbenzimidazole derivatives. The results of this study showed that certain 2-(thioalkyl)-1H-methylbenzimidazole and 2-(thioalkyl)-methyl-1-(piperidin-1-ylmethyl)benzimidazole derivatives possess antibacterial activities against clinical strains, such as Escherichia coli, Klebsiella pneumonia (Gram-negative bacteria), Staphylococcus aureus and Pseudomonas aeruginosa (Gram-positive bacteria). Following these favorable results, we extended the antibacterial evaluation of this series of molecules to environmental strains. The aim of this study was to assess the impact of the methyl-piperidine group fixed at position-1 of this new series of benzimidazoles on the antibacterial activity of environmental strains. In addition, we first evaluated the antibacterial activity of four 2-(thioalkyl)methylbenzimidazole derivatives and then that of five 2-(thioalkyl)-methyl-1-(piperidin-1-ylmethyl) benzimidazole derivatives. This study allowed us to show that compounds 1d and 1e could inhibit bacterial growth in vitro of the Enterobacteria P1 strain with inhibition diameters of 17.3 ± 0.6 mm and 10 ± 0.0 mm, respectively. However, addition of methyl-piperidinyl in this series showed that five (5) of 2-(thioalkyl)-methyl-1-(piperidin-1-ylmethyl) benzimidazole derivatives had an inhibitory effect on the in vitro growth of bacterial strains used except on Enterobacteria P2 with inhibition diameters between 10.0 ± 0.8 mm and 27.9 ± 1.4 mm. The introduction of the methyl-piperidinyl group at the 1-position of 2-(thioalkyl)-1H-methylbenzimidazole derivatives greatly improved the antibacterial activity against environmental bacteria such as Escherichia coli A1, A2, A3, and A4 and two Enterobacteria P1.展开更多
The economic transformation of the old industrial bases is a key research topic among geographers in China.In this paper,we propose that the concept of regional economic resilience(RER)has unique theoretical value in ...The economic transformation of the old industrial bases is a key research topic among geographers in China.In this paper,we propose that the concept of regional economic resilience(RER)has unique theoretical value in analyzing the economic transformation of the old industrial bases.We constructed an analytical framework and an index system and applied the conceptual tools to study the evolution of RER in the old industrial base of Liaoning Province in China,which is currently subjected to not only sudden shocks but‘slow burn’—longer term processes of change that may nevertheless affect the regional economy.There are four main findings:first,the evolution of RER in Liaoning can be divided into four stages from 2000 to 2015.Liaoning is currently in its conservation-release period,and the next stage will be a release-reorganization period.Second,the RER of the majority of the studied cities is lower than the average value for Liaoning,and this is mainly attributed to the relatively weak vulnerability-resistance and adaptability-transformation capacity of these cities.Third,the RER levels of the 14 cities in Liaoning differ significantly.At the first level is Shenyang and Dalian,at the second level is Dandong and Yingkou,and the third level comprises the remaining cities.Fourth,regional economic resilience is mainly determined by vulnerability-resistance,which indirectly reflects Liaoning’s lack of adaptability-transformation capacity,and the ability of the region to renew or create a new development path is weak.展开更多
The present paper covers electronic structures and spectra of the bases and the base pairs of nucleic acids calculated by using the INDO/S method. For free bases we give the energy levels of ground states and transiti...The present paper covers electronic structures and spectra of the bases and the base pairs of nucleic acids calculated by using the INDO/S method. For free bases we give the energy levels of ground states and transition energies of low-lying excited states and discuss the band characters. The results indicate that the calculated spectra are in good agreement with experimental values. On the other hand, our calculations for A-T and G-C pairs are very beneficial to understanding hydrogen bond properties of these pairs.展开更多
A novel method based on time-dependent stochastic orthogonal bases for stochastic response surface approximation is proposed to overcome the problem of significant errors in the utilization of the generalized polynomi...A novel method based on time-dependent stochastic orthogonal bases for stochastic response surface approximation is proposed to overcome the problem of significant errors in the utilization of the generalized polynomial chaos(GPC) method that approximates the stochastic response by orthogonal polynomials. The accuracy and effectiveness of the method are illustrated by different numerical examples including both linear and nonlinear problems. The results indicate that the proposed method modifies the stochastic bases adaptively, and has a better approximation for the probability density function in contrast to the GPC method.展开更多
On the basis of brief description of current situation of old industrial bases and primary industry of Liaoning Province, the paper introduces the general situation of agriculture-ecological zoning plan in Liaoning Pr...On the basis of brief description of current situation of old industrial bases and primary industry of Liaoning Province, the paper introduces the general situation of agriculture-ecological zoning plan in Liaoning Province. First, the ecological bases of agricultural zoning plan are introduced through various topographic and geomorphic types, regional climate differences and imbalanced distribution of natural resources; Second, in accordance with the theory of comparative advantage, distribution of production and resource economics, on the basis of comprehensive evaluation of agricultural natural resources, with the principle of fully excavating economic function of different natural resources, and in order to improve allocation efficiency of the two resources of market and government, the formation of ecological zoning plan of agriculture in Liaoning Province is analyzed; Third, according to Regional Layout Planning of Characteristic Agricultural Products of Liaoning Province (2006-2010), the paper describes basic layout of agriculture-ecological zoning plan in Liaoning Province. The policy support of agriculture-ecological zoning plan in Liaoning Province is analyzed from three aspects-support policy of functional zone major in producing grain, support policy of other characteristic agriculture-ecological zone and support measures of development of agriculture-ecological zone. The paper also analyzes experiences of agricultural development of old industrial bases in ecological zoning plan: First, agriculture-ecological zoning plan is a effective way of the revitalization of old industrial bases; Second, scientificity of plan is the basis of improving competitiveness of regional agriculture; Third, multi-input mechanism guiding by government is the key of agricultural packing effect; Fourth, integrated agricultural industrial chain is guarantee of realizing industrialization in ecological zone.展开更多
Using ideas based on supersymmetric quantum mechanics, we design canonical transformations of the usual position and momentum to create generalized “Cartesian-like” positions, W, and momenta, Pw , with unit Poisson ...Using ideas based on supersymmetric quantum mechanics, we design canonical transformations of the usual position and momentum to create generalized “Cartesian-like” positions, W, and momenta, Pw , with unit Poisson brackets. These are quantized by the usual replacement of the classical , x Px by quantum operators, leading to an infinite family of potential “operator observables”. However, all but one of the resulting operators are not Hermitian (formally self-adjoint) in the original position representation. Using either the chain rule or Dirac quantization, we show that the resulting operators are “quasi-Hermitian” relative to the x-representation and that all are Hermitian in the W-representation. Depending on how one treats the Jacobian of the canonical transformation in the expression for the classical momentum, Pw , quantization yields a) continuous mutually unbiased bases (MUB), b) orthogonal bases (with Dirac delta normalization), c) biorthogonal bases (with Dirac delta normalization), d) new W-harmonic oscillators yielding standard orthonormal bases (as functions of W) and associated coherent states and Wigner distributions. The MUB lead to W-generalized Fourier transform kernels whose eigenvectors are the W-harmonic oscillator eigenstates, with the spectrum (±1,±i) , as well as “W-linear chirps”. As expected, W,?Pw satisfy the uncertainty product relation: ΔWΔPw ≥1/2 , h=1.展开更多
Ganoderma(lingzhi)is a famous herbal medicine and edible supplement in oriental countries for a long history.In this study,a simple micellar electrokinetic chromatography(MEKC)method was established for the analysis o...Ganoderma(lingzhi)is a famous herbal medicine and edible supplement in oriental countries for a long history.In this study,a simple micellar electrokinetic chromatography(MEKC)method was established for the analysis of nucleosides and bases,the major bioactive components in Ganoderma for the first time.By optimizing the borate concentration,the sodium dodecyl sulfate(SDS)concentration and the pH value of running buffer,10 nucleosides and bases achieved an ideal separation.In real sample analysis,the developed method was successfully used to determine the 10 target analytes in 23 batches of Ganoderma samples from different regions.Results indicated that contents of 10 investigated analytes in each sample showed obvious variation.The principal components analysis(PCA)and hierarchical cluster analysis(HCA)analysis classified the samples into three groups,and the HCA tree visualized the relationships which was mainly contributed by geographical partition.The results indicated geographical origin to be an important factor that affect the accumulation of nucleosides and bases in Ganoderma.In summary,this study provides a simple and practical strategy for quality assessment and cultivation reference of Ganoderma.展开更多
We present wavelet bases made of piecewise (low degree) polynomial functions with an (arbitrary) assigned number of vanishing moments. We study some of the properties of these wavelet bases;in particular we consider t...We present wavelet bases made of piecewise (low degree) polynomial functions with an (arbitrary) assigned number of vanishing moments. We study some of the properties of these wavelet bases;in particular we consider their use in the approximation of functions and in numerical quadrature. We focus on two applications: integral kernel sparsification and digital image compression and reconstruction. In these application areas the use of these wavelet bases gives very satisfactory results.展开更多
Matrix-assisted laser desorption/ionization (MALDI) is a preferred and widely used mass spectrometric technique for the analysis of macromolecules. Limited UV-LDI matrices are available for the analysis of biomolecule...Matrix-assisted laser desorption/ionization (MALDI) is a preferred and widely used mass spectrometric technique for the analysis of macromolecules. Limited UV-LDI matrices are available for the analysis of biomolecules due to the restricted structural features to serve in the laser desorption/ionization mechanism with a problem of background signals appearing in the low mass region. This paper describes the application of Schiff base derivatives of acylhydrazide and isatin as alternate UV-LDI matrices for the analysis of peptides with significantly low background signals. Thirty one compounds have been successfully employed as matrices for the analysis of low molecular weight (LMW) peptides (α-Cyano-4-hydroxycinnamic acid (HCCA), a preferred choice for peptide analysis.展开更多
Four Schiff bases, from pyruvic acid (1) with amines containing N and S donor atoms, thiocarbohydrazide (2, 61%), 2-methyl-3-thiosemicarbazide (3, 26%), S-benzyldithiocarbazate (4, 51%) and S-n-octyldithiocarbazate (5...Four Schiff bases, from pyruvic acid (1) with amines containing N and S donor atoms, thiocarbohydrazide (2, 61%), 2-methyl-3-thiosemicarbazide (3, 26%), S-benzyldithiocarbazate (4, 51%) and S-n-octyldithiocarbazate (5, 63%) have been successfully synthesized. The conventional method was used and a series of novel linear and cyclic Schiff bases were obtained with or without catalyst. All the Schiff bases were fully characterized by CHN elemental analysis, FT-IR, 1H & 13C NMR, EI-MS and two of the Schiff bases were further characterized by X-ray crystallographic structure analysis. Compound 2 crystallizes in the triclinic space group P-1 and unit cell dimensions are: a = 4.1777(8), b = 5.9538(11), c = 13.458(3) Å, α = 92.759(6), β = 90.813(6), γ = 100.040(6)°, R1 = 0.0439. Compound 3 crystallizes in the orthorhombic space group P n a 2(1) and unit cell dimensions are: a = 5.5992(2), b = 11.3962(5), c = 10.6473(5), α = 92.759(6), β = 90.813(6), γ = 100.040(6)°, R1 = 0.0285. Compounds 2 and 3 were obtained as cyclic Schiff bases which are triazine derivatives.展开更多
Schiff bases are the most widely used organic compounds. They have been shown to exhibit a broad range of biological activities, including antifungal, antibacterial, antimalarial, antiproliferative, anti-inflammatory,...Schiff bases are the most widely used organic compounds. They have been shown to exhibit a broad range of biological activities, including antifungal, antibacterial, antimalarial, antiproliferative, anti-inflammatory, antiviral, and antipyretic properties. This review summarizes the synthesis and biological activities of Schiff bases and their complexes.展开更多
<span style="font-family:Verdana;">Three Schiff bases L</span><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;&quo...<span style="font-family:Verdana;">Three Schiff bases L</span><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;">, L</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> and L</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;"> were synthesized by condensing salicylalde</span><span style="font-family:Verdana;">hyde with 4-aminoantipyrine, ethylendiamine and 2-aminophenol respec</span><span style="font-family:Verdana;">tively and subsequently characterized by various physicochemical investigations. All the three compounds were screened for their </span><i><span style="font-family:Verdana;">In-vitro</span></i><span style="font-family:Verdana;"> antibacterial activity against two gram positive bacteria, </span><i><span style="font-family:Verdana;">Staphylococcus aureus</span></i><span style="font-family:Verdana;"> (S.A), </span><i><span style="font-family:Verdana;">Staphylococcus epidermidis</span></i><span style="font-family:Verdana;"> (S.E) and two gram negative bacteria </span><i><span style="font-family:Verdana;">Klebsiella</span></i><span><span><i><span style="font-family:""> </span></i></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i><span style="font-family:Verdana;">pneumoniae</span></i></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> (K.P) and </span><i><span style="font-family:Verdana;">Pseudomonas aeruginosa </span></i><span style="font-family:Verdana;">(</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">P.</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">A) by agar diffusion method. On comparing the results obtained with the activity of commercially available antibiotics such as Ciprofloxacin and Chloramphenicol, the newly synthesized compounds showed comparable antibacterial activities. The solvent methanol exhibit activity against all bacterial species with IZs ranging from 8 ± 0.25 to 17 ± 0.29 mm while the standard antibiotics Ciprofloxacin and Chloramphenicol exhibited an activities with IZs varying from 21.3 ± 0.31 to 28.3 ± 0.32 and 26.3 ± 0.24 mm to 32.3 ± 0.23 mm, respectively. However, the newly synthesized Schiff bases L</span><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;">, L</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> and L</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;"> showed IZs ranging from 7.4 ± 0.23 to 32.5 ± 0.14, 3 ± 0.57 to 12 ± 0.28 and 10 ± 0.20 to 32 ± 0.36 respectively. Among the Schiff bases, L</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;"> showed the activity (32 ± 0.36) against S.E and P.A </span><span style="font-family:Verdana;">which is higher than the activity of standard antibiotics Ciprofloxacin and</span><span style="font-family:Verdana;"> Chloramphenicol against the same bacterial strains. The results obtained revealed that all the synthesized Schiff bases exhibit appreciable antibacterial activity against all the bacteria species which potentially makes them, to apply as wide range antibacterial drugs, after further </span><i><span style="font-family:Verdana;">in-vivo</span></i><span style="font-family:Verdana;"> cytotoxicity investigations. Their activity can also be further modified by changing the functionality of precursors for Schiff base condensation.</span></span></span></span>展开更多
The transformation between physical bases and symmetry bases is extendedfrom SU_f^2 to SU_f^3.Its application in dibaryon calculation for both nonrelativistic andrelativistic quark model is discussed.
Notch proteins are transmembrane receptors which can transduce signals between cells.Upon binding to their ligands on the neighboring cells,notch receptors can be activated and undergo conformational changes which ena...Notch proteins are transmembrane receptors which can transduce signals between cells.Upon binding to their ligands on the neighboring cells,notch receptors can be activated and undergo conformational changes which enable their proteolysis by ADAM-family of metalloproteases<sup>[1]</sup>.The cleavage site of notch protein located on its hetrodimerizaton domain（HD）of the negative regulatory region（NRR）proximal to the N-terminal of the transmembrane helix.Recent crystal structures on several notch proteins<sup>[2-4]</sup>indicated that a series of three Lin12/Notch repeats（LNRs）wrap around the HD and bury the cleavage site to prevent it from proteolysis at the normal conditions without ligand binding.Studies indicated that notch/ligand binding may al-展开更多
基金This research was supported by the China National Natural Sciences Foundation(32070314)to J.X.the Science and Technology Innovation Fund project of Shanxi Agricultural University(2020BQ24)to P.Z.the Basic Research Program of Shanxi Province(Free Exploration)(20210302124369)to L.S.
文摘Boron is an essential microelement for plant growth.Tomato is one of the most cultivated fruits and vegetables in the world,and boron deficiency severely inhibits its yield and quality.However,the mechanism of tomato in response to boron deficiency remains largely unclear.Here,we investigated the physiological and molecular bases of the boron deficiency response in hydroponically grown tomato seedlings.Boron deficiency repressed the expression of genes associated with nitrogen metabolism,while it induced the expression of genes related to the pentose phosphate pathway,thereby altering carbon flow to provide energy for plants to cope with stress.Boron deficiency increased the accumulation of copper,manganese and iron,thereby maintaining chlorophyll content and photosynthetic efficiency at the early stage of stress.In addition,boron deficiency downregulated the expression of genes involved in cell wall organization and reduced the contents of pectin and cellulose in roots,ultimately retarding root growth.Furthermore,boron deficiency markedly altered phytohormone levels and signaling pathways in roots.The contents of jasmonic acid,jasmonoy1-L-isoleucine,trans-zeatin riboside,abscisic acid,salicylic acid,and SA glucoside were decreased;in contrast,the contents of isopentenyladenine riboside and ethylene precursor 1-aminocyclopropane-1-carboxylic acid were increased in the roots of boron-deficient tomato plants.These results collectively indicate that tomato roots reprogram carbon/nitrogen metabolism,alter cell wall components and modulate phytohormone pathways to survive boron deficiency.This study provides a theoretical basis for further elucidating the adaptive mechanism of tomato in response to boron deficiency.
文摘The aim of this paper is to given an algebraic computational method for finding maximal independent sets as well as the independent number of an arbitrary finite graph of n vertices G by strengthening the problem of finding maximal independent sets of G to the problem of finding k-independent sets in G for. It is shown that the existence of k-independent sets in G is equivalent to the existence of solutions of a system of multivariate polynomial equations. It follows that the problem of finding k-independent sets can be realized by using Gröbner bases of polynomial ideals. Since the number of k-independent sets is finite, the triangular equations composed by Gröbner bases are easier to be solved. Consequently, the maximal independent sets and the independent number of G are obtained after solving at most n such equations. Finally, the numerical example is presented to illustrate the effectiveness of this algebraic computational method.
基金Supported by 2021-2023 Postgraduate Talent Training Quality and Teaching Reform Project of Chengdu University (cdjgy2022035)2021-2023 Higher Education Talent Training Quality and Teaching Reform Project of Sichuan Province (JG2021-1109JG2021-130).
文摘Under the background of emerging agricultural education,practice bases are an important place to train profession talented person that match social needs,so it is very important to build stable and long-term practice bases.At present,the main problems in the construction of practice bases for postgraduates in local colleges and universities are mainly focusing on construction and neglecting management,imperfect cooperation mechanism and lack of teaching management effectively.It is of great significance to build a long-term management mechanism to ensure the education quality of practice bases.Therefore,constructing the mode of"double integration and double promotion of production and education"with practice bases as the carrier and realizing the organic combination of industrial needs and postgraduate projects is an important idea for local colleges and universities to train professional degree postgraduates to"know agriculture,love agriculture,strengthen agriculture and promote agriculture",and it also provides a reference for the mechanism construction of postgraduate bases.
文摘The compounds have been synthesized and characterized by routine MS, IR and NMR spectrometry methods. The compounds are all active on bacterial strains with the exception of Salmonella typhimirium, with a MIC value of 7.5 mg/mL. They show a percentage of anti-radical activity of 75.476 ± 5.070 for the compound DAN-S and of 68.142 ± 6.539 for the compound DAN-OV. The compounds are sensitive to the two champions used. DAN-S compound is then the most active.
文摘A previous study was conducted on the synthesis and antibacterial evaluation of Mannich bases of 2-(thioalkyl)-1H-methylbenzimidazole derivatives. The results of this study showed that certain 2-(thioalkyl)-1H-methylbenzimidazole and 2-(thioalkyl)-methyl-1-(piperidin-1-ylmethyl)benzimidazole derivatives possess antibacterial activities against clinical strains, such as Escherichia coli, Klebsiella pneumonia (Gram-negative bacteria), Staphylococcus aureus and Pseudomonas aeruginosa (Gram-positive bacteria). Following these favorable results, we extended the antibacterial evaluation of this series of molecules to environmental strains. The aim of this study was to assess the impact of the methyl-piperidine group fixed at position-1 of this new series of benzimidazoles on the antibacterial activity of environmental strains. In addition, we first evaluated the antibacterial activity of four 2-(thioalkyl)methylbenzimidazole derivatives and then that of five 2-(thioalkyl)-methyl-1-(piperidin-1-ylmethyl) benzimidazole derivatives. This study allowed us to show that compounds 1d and 1e could inhibit bacterial growth in vitro of the Enterobacteria P1 strain with inhibition diameters of 17.3 ± 0.6 mm and 10 ± 0.0 mm, respectively. However, addition of methyl-piperidinyl in this series showed that five (5) of 2-(thioalkyl)-methyl-1-(piperidin-1-ylmethyl) benzimidazole derivatives had an inhibitory effect on the in vitro growth of bacterial strains used except on Enterobacteria P2 with inhibition diameters between 10.0 ± 0.8 mm and 27.9 ± 1.4 mm. The introduction of the methyl-piperidinyl group at the 1-position of 2-(thioalkyl)-1H-methylbenzimidazole derivatives greatly improved the antibacterial activity against environmental bacteria such as Escherichia coli A1, A2, A3, and A4 and two Enterobacteria P1.
基金Under the auspices of National Natural Science Foundation of China(No.41571152,41771179).
文摘The economic transformation of the old industrial bases is a key research topic among geographers in China.In this paper,we propose that the concept of regional economic resilience(RER)has unique theoretical value in analyzing the economic transformation of the old industrial bases.We constructed an analytical framework and an index system and applied the conceptual tools to study the evolution of RER in the old industrial base of Liaoning Province in China,which is currently subjected to not only sudden shocks but‘slow burn’—longer term processes of change that may nevertheless affect the regional economy.There are four main findings:first,the evolution of RER in Liaoning can be divided into four stages from 2000 to 2015.Liaoning is currently in its conservation-release period,and the next stage will be a release-reorganization period.Second,the RER of the majority of the studied cities is lower than the average value for Liaoning,and this is mainly attributed to the relatively weak vulnerability-resistance and adaptability-transformation capacity of these cities.Third,the RER levels of the 14 cities in Liaoning differ significantly.At the first level is Shenyang and Dalian,at the second level is Dandong and Yingkou,and the third level comprises the remaining cities.Fourth,regional economic resilience is mainly determined by vulnerability-resistance,which indirectly reflects Liaoning’s lack of adaptability-transformation capacity,and the ability of the region to renew or create a new development path is weak.
文摘The present paper covers electronic structures and spectra of the bases and the base pairs of nucleic acids calculated by using the INDO/S method. For free bases we give the energy levels of ground states and transition energies of low-lying excited states and discuss the band characters. The results indicate that the calculated spectra are in good agreement with experimental values. On the other hand, our calculations for A-T and G-C pairs are very beneficial to understanding hydrogen bond properties of these pairs.
基金Project supported by the National Natural Science Foundation of China(Nos.11632011,11572189,and 51421092)the China Postdoctoral Science Foundation(No.2016M601585)
文摘A novel method based on time-dependent stochastic orthogonal bases for stochastic response surface approximation is proposed to overcome the problem of significant errors in the utilization of the generalized polynomial chaos(GPC) method that approximates the stochastic response by orthogonal polynomials. The accuracy and effectiveness of the method are illustrated by different numerical examples including both linear and nonlinear problems. The results indicate that the proposed method modifies the stochastic bases adaptively, and has a better approximation for the probability density function in contrast to the GPC method.
文摘On the basis of brief description of current situation of old industrial bases and primary industry of Liaoning Province, the paper introduces the general situation of agriculture-ecological zoning plan in Liaoning Province. First, the ecological bases of agricultural zoning plan are introduced through various topographic and geomorphic types, regional climate differences and imbalanced distribution of natural resources; Second, in accordance with the theory of comparative advantage, distribution of production and resource economics, on the basis of comprehensive evaluation of agricultural natural resources, with the principle of fully excavating economic function of different natural resources, and in order to improve allocation efficiency of the two resources of market and government, the formation of ecological zoning plan of agriculture in Liaoning Province is analyzed; Third, according to Regional Layout Planning of Characteristic Agricultural Products of Liaoning Province (2006-2010), the paper describes basic layout of agriculture-ecological zoning plan in Liaoning Province. The policy support of agriculture-ecological zoning plan in Liaoning Province is analyzed from three aspects-support policy of functional zone major in producing grain, support policy of other characteristic agriculture-ecological zone and support measures of development of agriculture-ecological zone. The paper also analyzes experiences of agricultural development of old industrial bases in ecological zoning plan: First, agriculture-ecological zoning plan is a effective way of the revitalization of old industrial bases; Second, scientificity of plan is the basis of improving competitiveness of regional agriculture; Third, multi-input mechanism guiding by government is the key of agricultural packing effect; Fourth, integrated agricultural industrial chain is guarantee of realizing industrialization in ecological zone.
文摘Using ideas based on supersymmetric quantum mechanics, we design canonical transformations of the usual position and momentum to create generalized “Cartesian-like” positions, W, and momenta, Pw , with unit Poisson brackets. These are quantized by the usual replacement of the classical , x Px by quantum operators, leading to an infinite family of potential “operator observables”. However, all but one of the resulting operators are not Hermitian (formally self-adjoint) in the original position representation. Using either the chain rule or Dirac quantization, we show that the resulting operators are “quasi-Hermitian” relative to the x-representation and that all are Hermitian in the W-representation. Depending on how one treats the Jacobian of the canonical transformation in the expression for the classical momentum, Pw , quantization yields a) continuous mutually unbiased bases (MUB), b) orthogonal bases (with Dirac delta normalization), c) biorthogonal bases (with Dirac delta normalization), d) new W-harmonic oscillators yielding standard orthonormal bases (as functions of W) and associated coherent states and Wigner distributions. The MUB lead to W-generalized Fourier transform kernels whose eigenvectors are the W-harmonic oscillator eigenstates, with the spectrum (±1,±i) , as well as “W-linear chirps”. As expected, W,?Pw satisfy the uncertainty product relation: ΔWΔPw ≥1/2 , h=1.
基金financially supported by the Research Committee of the University of Macao(MYRG2018-00239-ICMS and MYRG2014-00089-ICMS-QRCM)the Macao Science and Technology Development Fund(162/2017/A3)Guangzhou International Science and Technology Cooperation Project(File no.201807010044)。
文摘Ganoderma(lingzhi)is a famous herbal medicine and edible supplement in oriental countries for a long history.In this study,a simple micellar electrokinetic chromatography(MEKC)method was established for the analysis of nucleosides and bases,the major bioactive components in Ganoderma for the first time.By optimizing the borate concentration,the sodium dodecyl sulfate(SDS)concentration and the pH value of running buffer,10 nucleosides and bases achieved an ideal separation.In real sample analysis,the developed method was successfully used to determine the 10 target analytes in 23 batches of Ganoderma samples from different regions.Results indicated that contents of 10 investigated analytes in each sample showed obvious variation.The principal components analysis(PCA)and hierarchical cluster analysis(HCA)analysis classified the samples into three groups,and the HCA tree visualized the relationships which was mainly contributed by geographical partition.The results indicated geographical origin to be an important factor that affect the accumulation of nucleosides and bases in Ganoderma.In summary,this study provides a simple and practical strategy for quality assessment and cultivation reference of Ganoderma.
文摘We present wavelet bases made of piecewise (low degree) polynomial functions with an (arbitrary) assigned number of vanishing moments. We study some of the properties of these wavelet bases;in particular we consider their use in the approximation of functions and in numerical quadrature. We focus on two applications: integral kernel sparsification and digital image compression and reconstruction. In these application areas the use of these wavelet bases gives very satisfactory results.
文摘Matrix-assisted laser desorption/ionization (MALDI) is a preferred and widely used mass spectrometric technique for the analysis of macromolecules. Limited UV-LDI matrices are available for the analysis of biomolecules due to the restricted structural features to serve in the laser desorption/ionization mechanism with a problem of background signals appearing in the low mass region. This paper describes the application of Schiff base derivatives of acylhydrazide and isatin as alternate UV-LDI matrices for the analysis of peptides with significantly low background signals. Thirty one compounds have been successfully employed as matrices for the analysis of low molecular weight (LMW) peptides (α-Cyano-4-hydroxycinnamic acid (HCCA), a preferred choice for peptide analysis.
文摘Four Schiff bases, from pyruvic acid (1) with amines containing N and S donor atoms, thiocarbohydrazide (2, 61%), 2-methyl-3-thiosemicarbazide (3, 26%), S-benzyldithiocarbazate (4, 51%) and S-n-octyldithiocarbazate (5, 63%) have been successfully synthesized. The conventional method was used and a series of novel linear and cyclic Schiff bases were obtained with or without catalyst. All the Schiff bases were fully characterized by CHN elemental analysis, FT-IR, 1H & 13C NMR, EI-MS and two of the Schiff bases were further characterized by X-ray crystallographic structure analysis. Compound 2 crystallizes in the triclinic space group P-1 and unit cell dimensions are: a = 4.1777(8), b = 5.9538(11), c = 13.458(3) &ARING;, α = 92.759(6), β = 90.813(6), γ = 100.040(6)°, R1 = 0.0439. Compound 3 crystallizes in the orthorhombic space group P n a 2(1) and unit cell dimensions are: a = 5.5992(2), b = 11.3962(5), c = 10.6473(5), α = 92.759(6), β = 90.813(6), γ = 100.040(6)°, R1 = 0.0285. Compounds 2 and 3 were obtained as cyclic Schiff bases which are triazine derivatives.
文摘Schiff bases are the most widely used organic compounds. They have been shown to exhibit a broad range of biological activities, including antifungal, antibacterial, antimalarial, antiproliferative, anti-inflammatory, antiviral, and antipyretic properties. This review summarizes the synthesis and biological activities of Schiff bases and their complexes.
文摘<span style="font-family:Verdana;">Three Schiff bases L</span><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;">, L</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> and L</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;"> were synthesized by condensing salicylalde</span><span style="font-family:Verdana;">hyde with 4-aminoantipyrine, ethylendiamine and 2-aminophenol respec</span><span style="font-family:Verdana;">tively and subsequently characterized by various physicochemical investigations. All the three compounds were screened for their </span><i><span style="font-family:Verdana;">In-vitro</span></i><span style="font-family:Verdana;"> antibacterial activity against two gram positive bacteria, </span><i><span style="font-family:Verdana;">Staphylococcus aureus</span></i><span style="font-family:Verdana;"> (S.A), </span><i><span style="font-family:Verdana;">Staphylococcus epidermidis</span></i><span style="font-family:Verdana;"> (S.E) and two gram negative bacteria </span><i><span style="font-family:Verdana;">Klebsiella</span></i><span><span><i><span style="font-family:""> </span></i></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i><span style="font-family:Verdana;">pneumoniae</span></i></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> (K.P) and </span><i><span style="font-family:Verdana;">Pseudomonas aeruginosa </span></i><span style="font-family:Verdana;">(</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">P.</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">A) by agar diffusion method. On comparing the results obtained with the activity of commercially available antibiotics such as Ciprofloxacin and Chloramphenicol, the newly synthesized compounds showed comparable antibacterial activities. The solvent methanol exhibit activity against all bacterial species with IZs ranging from 8 ± 0.25 to 17 ± 0.29 mm while the standard antibiotics Ciprofloxacin and Chloramphenicol exhibited an activities with IZs varying from 21.3 ± 0.31 to 28.3 ± 0.32 and 26.3 ± 0.24 mm to 32.3 ± 0.23 mm, respectively. However, the newly synthesized Schiff bases L</span><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;">, L</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> and L</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;"> showed IZs ranging from 7.4 ± 0.23 to 32.5 ± 0.14, 3 ± 0.57 to 12 ± 0.28 and 10 ± 0.20 to 32 ± 0.36 respectively. Among the Schiff bases, L</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;"> showed the activity (32 ± 0.36) against S.E and P.A </span><span style="font-family:Verdana;">which is higher than the activity of standard antibiotics Ciprofloxacin and</span><span style="font-family:Verdana;"> Chloramphenicol against the same bacterial strains. The results obtained revealed that all the synthesized Schiff bases exhibit appreciable antibacterial activity against all the bacteria species which potentially makes them, to apply as wide range antibacterial drugs, after further </span><i><span style="font-family:Verdana;">in-vivo</span></i><span style="font-family:Verdana;"> cytotoxicity investigations. Their activity can also be further modified by changing the functionality of precursors for Schiff base condensation.</span></span></span></span>
基金The project supported by the NSFC,National Education Committee FundNational ScienceTechnology Committee FundJiangsu Province Education Committee Youth Fund.
文摘The transformation between physical bases and symmetry bases is extendedfrom SU_f^2 to SU_f^3.Its application in dibaryon calculation for both nonrelativistic andrelativistic quark model is discussed.
基金supported by grants from Natural Science Foundations of China(31070827, 31222022,and 81161120424)the Knowledge Innovation Program of the Chinese Academy of Sciens
文摘Notch proteins are transmembrane receptors which can transduce signals between cells.Upon binding to their ligands on the neighboring cells,notch receptors can be activated and undergo conformational changes which enable their proteolysis by ADAM-family of metalloproteases<sup>[1]</sup>.The cleavage site of notch protein located on its hetrodimerizaton domain（HD）of the negative regulatory region（NRR）proximal to the N-terminal of the transmembrane helix.Recent crystal structures on several notch proteins<sup>[2-4]</sup>indicated that a series of three Lin12/Notch repeats（LNRs）wrap around the HD and bury the cleavage site to prevent it from proteolysis at the normal conditions without ligand binding.Studies indicated that notch/ligand binding may al-
