Deep understanding of the fluorescence quenching mechanisms of probes plays a crucial role in developing their practical applications.The fluorescence quenching mechanism of hydrazine-based fluorescence probes needs t...Deep understanding of the fluorescence quenching mechanisms of probes plays a crucial role in developing their practical applications.The fluorescence quenching mechanism of hydrazine-based fluorescence probes needs to be clarified up to the present.Herein,we designed and synthesized a new hydrazine-based fluorescence probe(HA-Na)based on the naphthalimide skeleton.We clarified the molecular origin of the non-fluorescence of this probe with the aid of computational chemistry and spectroscopic analysis.We showed that the significant rotation of the hydrazine group in the excited state potential energy surface,which caused the complete charge separation,was responsible for the fluorescence quenching of the probe in an organic solvent.Once the rotation was prevented in an aggregative state or high-viscosity solution,the fluorescence of the probe recovered.In other words,the fluorescence quenching mechanism of hydrazine-based fluorescence probes was attributed to the formation of a twisted intramolecular charge transfer(TICT)state.More importantly,we demonstrated that this fluorescence molecular rotor could be used to monitor the autophagy process in living cells by detecting lysosomal viscosity changes during starvation.Altogether,this work provides an essential theoretical basis for the developing potential hydrazine-based fluorescence molecular rotors.展开更多
The title complex is widely used as an efficient key component of Ziegler-Natta catalyst for stereospecific polymerization of dienes to produce synthetic rubbers. However, the quantitative structure-activity relations...The title complex is widely used as an efficient key component of Ziegler-Natta catalyst for stereospecific polymerization of dienes to produce synthetic rubbers. However, the quantitative structure-activity relationship（QSAR） of this kind of complexes is still not clear mainly due to the difficulties to obtain their geometric molecular structures through laboratory experiments. An alternative solution is the quantum chemistry calculation in which the comformational population shall be determined. In this study, ten conformers of the title complex were obtained with the function of molecular dynamics conformational search in Gabedit 2.4.8, and their geometry optimization and thermodynamics calculation were made with a Sparkle/PM7 approach in MOPAC 2012. Their Gibbs free energies at 1 atm. and 298.15 K were calculated. Population of the conformers was further calculated out according to the theory of Boltzmann distribution, indicating that one of the ten conformers has a dominant population of 77.13%.展开更多
For living anionic polymerization(LAP),solvent has a great influence on both reaction mechanism and kinetics.In this work,by using the classical butyl lithium-styrene polymerization as a model system,the effect of sol...For living anionic polymerization(LAP),solvent has a great influence on both reaction mechanism and kinetics.In this work,by using the classical butyl lithium-styrene polymerization as a model system,the effect of solvent on the mechanism and kinetics of LAP was revealed through a strategy combining density functional theory(DFT)calculations and kinetic modeling.In terms of mechanism,it is found that the stronger the solvent polarity,the more electrons transfer from initiator to solvent through detailed energy decomposition analysis of electrostatic interactions between initiator and solvent molecules.Furthermore,we also found that the stronger the solvent polarity,the higher the monomer initiation energy barrier and the smaller the initiation rate coefficient.Counterintuitively,initiation is more favorable at lower temperatures based on the calculated results ofΔG_(TS).Finally,the kinetic characteristics in different solvents were further examined by kinetic modeling.It is found that in benzene and n-pentane,the polymerization rate exhibits first-order kinetics.While,slow initiation and fast propagation were observed in tetrahydrofuran(THF)due to the slow free ion formation rate,leading to a deviation from first-order kinetics.展开更多
This study involved the assessment of the MNI2SX/Def2TZVP/H_(2)O model chemistry to enhance the understanding of the structural composition of the marine peptide Hemiasterlin and its derivatives A and B used in cancer...This study involved the assessment of the MNI2SX/Def2TZVP/H_(2)O model chemistry to enhance the understanding of the structural composition of the marine peptide Hemiasterlin and its derivatives A and B used in cancer treatment.The Conceptual Density Functional theory was used in the calculation of molecular properties of the system chemical descriptors during the study.Integration of the active molecular regions into their respective Fukui functions was used in the selection of electrophilic and nucleophilic attacks.Additionally,the proposed correlation between global hardness and the pKa was used as the basis of deriving accurate predictions for the pKa values while a homology technique was used in the prediction of bioactivity and bioavailability scores of the peptides under investigation.展开更多
Background:Chaetomorpha aerea,a marine green alga,has drawn attention because of its rich phytochemical constituents and therapeutic benefits.Using an integrated approach that combined in vitro,in vivo,and in silico a...Background:Chaetomorpha aerea,a marine green alga,has drawn attention because of its rich phytochemical constituents and therapeutic benefits.Using an integrated approach that combined in vitro,in vivo,and in silico approaches,this work examined the antioxidant,anti-inflammatory,and antidiabetic qualities of acetone extract of C.aerea(AECA).Methods:Total phenolic and flavonoid concentrations of AECA were measured.Antioxidant activity was assessed using the DPPH and ABTS free radical scavenging assays.In vitro protein denaturation and in vivo carrageenan-induced paw edema models were employed to evaluate the anti-inflammatory potential,whereas antidiabetic activity was assessed using in vitroα-amylase inhibition and in vivo oral glucose tolerance test(OGTT).Molecular docking and ADME/T analysis were employed to further analyze bioactive compounds identified using gas chromatography–mass spectrometry(GC–MS).Result:Antioxidant activity demonstrated a minimum inhibitory concentration(IC_(50))of 107.44μg/mL for DPPH and 118.23μg/mL for ABTS.In vitro anti-inflammatory assays indicated a suppression of protein denaturation at a concentration of 102μg/mL(IC_(50)),where AECA(400 mg/kg)resulted in a 27%reduction in paw edema at 6 h in the mouse model.In vitro antidiabetic test indicatedα-amylase inhibition with an IC_(50) value of 70.72μg/mL,and in the OGTT,a significant lowering of blood glucose was recorded at 120 min in mice.Strong binding affinities were observed for stigmasta-5,24(28)-dien-3-ol,identified using GC–MS,with values of−9.9 kcal/mol forα-amylase and−8.0 kcal/mol for cyclooxygenase-2.Conclusion:C.aerea serves as an effective natural remedy for oxidative stress,inflammation,and hyperglycemia.These findings advocate for further clinical and mechanistic investigations to optimize therapeutic efficacy.展开更多
Deep Learning has been widely used to model soft sensors in modern industrial processes with nonlinear variables and uncertainty.Due to the outstanding ability for high-level feature extraction,stacked autoencoder(SAE...Deep Learning has been widely used to model soft sensors in modern industrial processes with nonlinear variables and uncertainty.Due to the outstanding ability for high-level feature extraction,stacked autoencoder(SAE)has been widely used to improve the model accuracy of soft sensors.However,with the increase of network layers,SAE may encounter serious information loss issues,which affect the modeling performance of soft sensors.Besides,there are typically very few labeled samples in the data set,which brings challenges to traditional neural networks to solve.In this paper,a multi-scale feature fused stacked autoencoder(MFF-SAE)is suggested for feature representation related to hierarchical output,where stacked autoencoder,mutual information(MI)and multi-scale feature fusion(MFF)strategies are integrated.Based on correlation analysis between output and input variables,critical hidden variables are extracted from the original variables in each autoencoder's input layer,which are correspondingly given varying weights.Besides,an integration strategy based on multi-scale feature fusion is adopted to mitigate the impact of information loss with the deepening of the network layers.Then,the MFF-SAE method is designed and stacked to form deep networks.Two practical industrial processes are utilized to evaluate the performance of MFF-SAE.Results from simulations indicate that in comparison to other cutting-edge techniques,the proposed method may considerably enhance the accuracy of soft sensor modeling,where the suggested method reduces the root mean square error(RMSE)by 71.8%,17.1%and 64.7%,15.1%,respectively.展开更多
The low-temperature coal tar contains a considerable number of oxygen-containing compounds,which results in poor quality.The catalytic hydrodeoxygenation of oxygen-containing compound to an added-value chemical compou...The low-temperature coal tar contains a considerable number of oxygen-containing compounds,which results in poor quality.The catalytic hydrodeoxygenation of oxygen-containing compound to an added-value chemical compound is one of the most efficient methods to upgrade coal tar.In this study,density functional theory calculations are employed to assess and analyze in detail the hydrodeoxygenation of dibenzofuran,as a model compound of coal tar,on the Ni(111)surface.The obtained results indicate that dibenzofuran can be firstly hydrogenated to tetra hy d rod i be nzofura n and hexahydfodibenzofufan.The five-membered-ring opening reaction of tetrahydrodibenzofuran is more straightforward than that of hexahydrodibenzofuran(Ea=0.71 eV vs.1.66 eV).Then,both pathways generate an intermediate 2-cyclohexylphenoxy compound.One part of 2-cyclohexylphenoxy is hydrogenated to 2-cyclohexylphenol and consecutively hydrogenated to cyclohexylcyclohexanol,and another part is directly hydrogenated to cyclohexylcyclohexanone.The hydrogenated intermediates of2-cyclohexylphenol have higher deoxygenation barriers than 2-cyclohexylphenol and cyclohexylcy clohexanol.During the hydrogenation process of cyclohexylcyclohexanone to cyclohexylcyclohexanol,the intermediate 26,formed by adding H to O atom of cyclohexylcyclohexanone,exhibits the lowest deoxygenation barrier of 1.08 eV.High hydrogen coverage may promote the hydrogenation of tetrahydrodibenzofuran,hexahydrodibenzofuran,and intermediate 26 to generate dodecahydrodibenzofuran and cyclohexylcyclohexanol.This dibenzofuran hydrodeoxygenation reaction mechanism corroborates well with previous experimental results and provides a theoretical basis for further optimization of the design of nickel-based catalysts.展开更多
N-alkyl imidazolium carbonate ionic liquids were employed to separate and recover naphthenic acid from model oils.The effects of the cationic and anionic structures of ionic liquids and operating conditions on the dea...N-alkyl imidazolium carbonate ionic liquids were employed to separate and recover naphthenic acid from model oils.The effects of the cationic and anionic structures of ionic liquids and operating conditions on the deacidification performance were investigated.The deacidification performance of traditional organic solvents was also investigated for comparison.The results indicated that the naphthenic acid could be completely removed from the model oil with a small mass ratio of ionic liquid to oil.The extracted naphthenic acid was regenerated with a recovery of up to 92%.In addition,imidazolium carbonate ionic liquids could be successfully regenerated and recycled.The mechanism of interaction between imidazole ionic liquids and the naphthenic acid molecules were explained by Gauss calculation.展开更多
Ion channels,as membrane proteins,are the sensors of the cell.They act as the first line of communication with the world beyond the plasma membrane and transduce changes in the external and internal environments into ...Ion channels,as membrane proteins,are the sensors of the cell.They act as the first line of communication with the world beyond the plasma membrane and transduce changes in the external and internal environments into unique electrical signals to shape the responses of excitable cells.Because of their importance in cellular communication,ion channels have been intensively studied at the structural and functional levels.Here,we summarize the diverse approaches,including molecular and cellular,chemical,optical,biophysical,and computational,used to probe the structural and functional rearrangements that occur during channel activation（or sensitization）,inactivation（or desensitization）,and various forms of modulation.The emerging insights into the structure and function of ion channels by multidisciplinary approaches allow the development of new pharmacotherapies as well as new tools useful in controlling cellular activity.展开更多
Metal–organic frameworks(MOFs)are highly promising porous materials known for their exceptional porosity,extensive surface area,and customizable pore structures,making them an ideal solution for hydrogen storage.Howe...Metal–organic frameworks(MOFs)are highly promising porous materials known for their exceptional porosity,extensive surface area,and customizable pore structures,making them an ideal solution for hydrogen storage.However,most MOFs research remains confined to the laboratory,lacking practical applications.To address this,the author proposes a shift towards practical applications,the creation of a comprehensive MOFs database,alignment of synthesis with practical considerations,and diversification of MOFs applications.These steps are crucial for harnessing the full potential of MOFs in real-world energy challenges.展开更多
Advances in computational chemistry have greatly increased its effectiveness and attractiveness as an emerging adjunct to experimental chemistry but also as an independent research field. This work studied some basic ...Advances in computational chemistry have greatly increased its effectiveness and attractiveness as an emerging adjunct to experimental chemistry but also as an independent research field. This work studied some basic bonding Parameters, geometry, Uv-Visible spectra, HOMO-LUMO and harmonic vibrational frequencies of Quinoline were investigated by using density functional theory (DFT/6-31+ (d, p)) methods. The calculated wave numbers (B3LYP) agree properly with the determined wave numbers. The results obtained are then as compared with experimental statistics in which available. The structural parameters;thermochemistry, rotational constants, IR spectra and frequencies, bond distances, angles and dipole moment were obtained from the optimized stable geometries of the compound. The computed optimized geometric bond lengths and bond angles show good agreement with experimental data of the title compound. The calculated HOMO and LUMO energies indicate that charge transfer occurs within the molecule.展开更多
Possible structures of La 2C 2 were studied and proposed by use of density functional theory. All proposed isomers are planar. The results indicate that the structure with the lowest symmetry ( C 1) is the most ...Possible structures of La 2C 2 were studied and proposed by use of density functional theory. All proposed isomers are planar. The results indicate that the structure with the lowest symmetry ( C 1) is the most stable. Linear isomers are not favored .展开更多
Lithium-sulfur(Li-S)batteries are regarded as one of the most promising next-generation energy storage systems due to their high theoretical specific energy density and low cost.However,serious shuttle effect and slug...Lithium-sulfur(Li-S)batteries are regarded as one of the most promising next-generation energy storage systems due to their high theoretical specific energy density and low cost.However,serious shuttle effect and sluggish lithium polysulfides(LiPSs)redox kinetics severely impede the practical application of Li-S batteries.Employing polar sulfur hosts is an effective strategy to alleviate the above problems.Herein,the potential of two-dimensional(2D)Ti_(2)B-based sulfur hosts for Li-S batteries was comprehensively explored using first-principles calculations.The results show that functional groups of Ti_(2)B can significantly modulate its structural properties,thus affecting its interaction with sulfurcontaining species.Among S,Se,F,Cl,and Br elements,Ti_(2)B terminated with S and Se atoms possess stronger adsorption capability towards soluble Li_(2)S_(8),Li_(2)S_(6),and Li_(2)S_(4),obviously stronger than organic electrolytes,which indicates that they can completely suppress the shuttle effect.Besides,Ti_(2)BS_(2)and Ti_(2)BSe_(2)can powerfully expedite the electrochemical conversion of LiPSs.Moreover,the decomposition energy barrier of Li_(2)S and diffusion energy barrier of single Li ion on them are also fairly low,manifesting their excellent catalytic performance towards the oxidation of Li_(2)S.Finally,Ti_(2)BS_(2)and Ti_(2)BSe_(2)always keep metallic conductivity during the whole charge/discharge process.Taking all this into account,Ti_(2)BS_(2)and Ti_(2)BSe_(2)are proposed as promising bifunctional sulfur hosts for Li-S batteries.Our results suggest that increasing the proportion of S and Se groups during the synthesis of Ti_(2)B monolayers is greatly helpful for obtaining high-performance Li-S batteries.Besides,our work not only reveals the huge potential of 2D transition metal borides in Li-S batteries,but also provides insightful guidance for the design and screening of new efficient sulfur cathodes.展开更多
OX_(2)(X=halogen)molecules was studied theoretically.Calculation results show that delocalizedπ_(3)^(6) bonds exist in their electronic structures and O atoms adopt the sp^(2) type of hybridization,which violates the...OX_(2)(X=halogen)molecules was studied theoretically.Calculation results show that delocalizedπ_(3)^(6) bonds exist in their electronic structures and O atoms adopt the sp^(2) type of hybridization,which violates the prediction of the valence shell electron pair repulsion theory of sp^(3) type.Delocalization stabilization energy is proposed to measure the contribution of delocalizedπ_(3)^(6) bond to energy decrease and proves to bring extra-stability to the molecule.These phenomena can be summarized as a kind of coordinating effect.展开更多
The achievement of electrical spin control is highly desirable.One promising strategy involves electrically mod-ulating the Rashba spin orbital coupling effect in materials.A semiconductor with high sensitivity in its...The achievement of electrical spin control is highly desirable.One promising strategy involves electrically mod-ulating the Rashba spin orbital coupling effect in materials.A semiconductor with high sensitivity in its Rashba constant to external electric fields holds great potential for short channel lengths in spin field-effect transistors,which is crucial for preserving spin coherence and enhancing integration density.Hence,two-dimensional(2D)Rashba semiconductors with large Rashba constants and significant electric field responses are highly desirable.Herein,by employing first-principles calculations,we design a thermodynamically stable 2D Rashba semiconductor,YSbTe_(3),which possesses an indirect band gap of 1.04 eV,a large Rashba constant of 1.54 eV·Åand a strong electric field response of up to 4.80 e·Å^(2).In particular,the Rashba constant dependence on the electric field shows an unusual nonlinear relationship.At the same time,YSbTe_(3)has been identified as a 2D ferroelectric material with a moderate polarization switching energy barrier(~0.33 eV per formula).By changing the electric polarization direction,the Rashba spin texture of YSbTe_(3)can be reversed.These out-standing properties make the ferroelectric Rashba semiconductor YSbTe_(3)quite promising for spintronic applications.展开更多
Tetranitrodiazidoacetylhexaazaisowurtzitane (TNDAIW) is a novel polyazapolycyclic caged polyazidonitramine explosive first synthesized in our laboratory. Two possible conformers of TNDAIW with C_s symmetry were fully ...Tetranitrodiazidoacetylhexaazaisowurtzitane (TNDAIW) is a novel polyazapolycyclic caged polyazidonitramine explosive first synthesized in our laboratory. Two possible conformers of TNDAIW with C_s symmetry were fully optimized using the HF/6-31G(d) level of theory. TNDAIW with the optimized geometries probably exists, and is predicted to be more stable than epsilon-hexanitrohexaazoisowurtzitane (epsilon-CL-20) based on the lengths of N-N, C-C and C-N bonds. The impact and shock sensitivities are lower for the possible conformers of TNDAIW than those for epsilon-CL-20. TNDAIW with the optimized possible conformers is estimated to be a promising novel high energy density explosive.展开更多
Nitrogen molecules Nx have been the subject of much recent research because of their potential as high-energy materials. Many nitrogen molecules dissociate with very low barriers, including molecules such as acyclic N...Nitrogen molecules Nx have been the subject of much recent research because of their potential as high-energy materials. Many nitrogen molecules dissociate with very low barriers, including molecules such as acyclic N4 that are essentially unbound. A number of studies have reported the ability of heteroatoms to stabilize complex nitrogen molecules. In the present study, the energetic and electronic properties of scandium（Ⅰ） and titanium（Ⅱ） complexes with N2 and N4 are calculated and discussed. Dissociation energies and singlet-triplet energies are determined by theoretical calculations using second-order perturbation theory （MP2） in conjunction with the Dunning basis sets.展开更多
In this study, the chiral separation mechanisms of Dansyl amino acids, including Dansyl-Leucine (Dans-Leu), Dansyl-Norleucine (Dans-Nor), Dansyl-Tryptophan (Dans-Trp) and Dansyl-Phenylalanine (Dans-Phe) binding to pol...In this study, the chiral separation mechanisms of Dansyl amino acids, including Dansyl-Leucine (Dans-Leu), Dansyl-Norleucine (Dans-Nor), Dansyl-Tryptophan (Dans-Trp) and Dansyl-Phenylalanine (Dans-Phe) binding to poly-sodium </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">N</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:Verdana;">-undecanoyl-(L)-Leucylvalinate, poly (SULV), were investigated using molecular dynamics simulations. Micellar electrokinetic chromatography (MEKC) has previously shown that when separating the enantiomers of these aforementioned Dansyl amino acids, the L-enantiomers bind stronger to poly (SULV) than the D-enantiomers. This study aims to investigate the molecular interactions that govern chiral recognition in these systems using computational methods. This study reveals that the computationally-calculated binding free energy values for Dansyl enantiomers binding to poly (SULV) are in agreement with the enantiomeric order produced in experimental MEKC studies. The L-enantiomers of Dans-Leu, Dans-Nor, Dans-Trp, and Dans-Phe binding to their preferred binding pockets in poly (SULV) yielded binding free energy values of </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">21.8938, </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">22.1763, </span><span style="font-family:Verdana;">-</span><span style="font-family:""><span style="font-family:Verdana;">21.3329 </span><span style="font-family:Verdana;">and </span></span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">13.3349 kJ</span><span style="font-family:Verdana;">·</span><span style="font-family:Verdana;">mol</span><sup><span style="font-family:Verdana;">-</span></sup><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;">, respectively. The D-enantiomers of Dans-Leu, Dans-Nor</span><span style="font-family:Verdana;">, Dans-Trp, and Dans-Phe binding to their preferred binding pockets in poly (SULV) yielded binding free energy values of </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">14.5811, </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">15.9457, </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">13.6408, and </span><span style="font-family:Verdana;">-</span><span style="font-family:""><span style="font-family:Verdana;">12.0959</span><b> </b><span style="font-family:Verdana;">kJ</span></span><span style="font-family:Verdana;">·</span><span style="font-family:Verdana;">mol</span><sup><span style="font-family:Verdana;">-</span></sup><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;">, respectively. Furthermore, hydrogen bonding analyses w</span><span style="font-family:Verdana;">ere</span><span style="font-family:Verdana;"> used to investigate and elucidate the molecular interactions that govern chiral recognition in these molecular systems.展开更多
Continuous cortisol monitoring(CCM)is essential for stress management,providing physiological insights into psychology and physical health.However,promising platform for CCM urges the design of effective biorecognitio...Continuous cortisol monitoring(CCM)is essential for stress management,providing physiological insights into psychology and physical health.However,promising platform for CCM urges the design of effective biorecognition moieties and the skin integration of sophisticated functions.Herein,we present a computationally-assisted wearable system for CCM(CWSCCM)that leverages cutting-edge interdisciplinary technologies of in-situ regenerative molecularly imprinted polymers(MIP),signal amplifier organic electrochemical transistor(OECT),iontophoresis-based sweat induction,and microfluidic sweat sampling.The highly integrated system incorporated with OECT biosensor enables in-situ MIP regeneration,and offers continuous approach for cortisol monitoring,with an ultra-low limit of detection of0.36 nmol/L.We validated the capability of the CWSCCM for long-term cortisol circadian rhythm monitoring in human participants,which shows superior sensitivity,selectivity,and continuous monitoring capabilities.In conclusion,we demonstrated how computational chemistry and OECT technology can extend the capabilities of current wearable CCM,which could potentially advance closed-loop therapeutics applications.展开更多
Currently,the iron chromium redox flow battery(ICRFB)has become a research hotspot in the energy storage field owing to its low cost and easily-scaled-up.However,the activity of electrolyte is still ambiguous due to i...Currently,the iron chromium redox flow battery(ICRFB)has become a research hotspot in the energy storage field owing to its low cost and easily-scaled-up.However,the activity of electrolyte is still ambiguous due to its complicated solution environment.Herein,we performed a pioneering investigation on the coordination behavior and transformation mechanism of Cr^(3+)in electrolyte and prediction of impurity ions impact through quantum chemistry computations.Based on the structure and symmetry of electrostatic potential distribution,the activity of different Cr^(3+)complex ions is confirmed as[Cr(H2O)5Cl]^(2+)>[Cr(H2O)4Cl2]+>[Cr(H2O)6]^(3+).The transformation mechanism between[Cr(H2O)6]^(3+)and[Cr(H2O)5Cl]^(2+)is revealed.We find the metal impurity ions(especially Mg^(2+))can exacerbate the electrolyte deactivation by reducing the transformation energy barrier from[Cr(H2O)5Cl]^(2+)(24.38 kcal mol^(−1))to[Cr(H2O)6]^(3+)(16.23 kcal mol^(−1)).The solvent radial distribution and mean square displacement in different solvent environments are discussed and we conclude that the coordination configuration limits the diffusivity of Cr^(3+).This work provides new insights into the activity of electrolyte,laying a fundamental sense for the electrolyte in ICRFB.展开更多
基金supported by the Hainan Provincial Natural Science Foundation of China(123MS001 and 123QN181)the National Natural Science Foundation of China(32360236,52063011,22203024)+2 种基金the Collaborative Innovation Center Foundation of the Hainan University(XTCX2022JKB03)the Research Start-up Fund Project of Hainan University(No.RZ2200001217 and RZ2200001216)Tianjin University-Hainan University Independent Innovation Fund(RZ2200003795).
文摘Deep understanding of the fluorescence quenching mechanisms of probes plays a crucial role in developing their practical applications.The fluorescence quenching mechanism of hydrazine-based fluorescence probes needs to be clarified up to the present.Herein,we designed and synthesized a new hydrazine-based fluorescence probe(HA-Na)based on the naphthalimide skeleton.We clarified the molecular origin of the non-fluorescence of this probe with the aid of computational chemistry and spectroscopic analysis.We showed that the significant rotation of the hydrazine group in the excited state potential energy surface,which caused the complete charge separation,was responsible for the fluorescence quenching of the probe in an organic solvent.Once the rotation was prevented in an aggregative state or high-viscosity solution,the fluorescence of the probe recovered.In other words,the fluorescence quenching mechanism of hydrazine-based fluorescence probes was attributed to the formation of a twisted intramolecular charge transfer(TICT)state.More importantly,we demonstrated that this fluorescence molecular rotor could be used to monitor the autophagy process in living cells by detecting lysosomal viscosity changes during starvation.Altogether,this work provides an essential theoretical basis for the developing potential hydrazine-based fluorescence molecular rotors.
基金supported by the National Natural Science Foundation of China(No.21476119)
文摘The title complex is widely used as an efficient key component of Ziegler-Natta catalyst for stereospecific polymerization of dienes to produce synthetic rubbers. However, the quantitative structure-activity relationship（QSAR） of this kind of complexes is still not clear mainly due to the difficulties to obtain their geometric molecular structures through laboratory experiments. An alternative solution is the quantum chemistry calculation in which the comformational population shall be determined. In this study, ten conformers of the title complex were obtained with the function of molecular dynamics conformational search in Gabedit 2.4.8, and their geometry optimization and thermodynamics calculation were made with a Sparkle/PM7 approach in MOPAC 2012. Their Gibbs free energies at 1 atm. and 298.15 K were calculated. Population of the conformers was further calculated out according to the theory of Boltzmann distribution, indicating that one of the ten conformers has a dominant population of 77.13%.
基金financially supported by the National Natural Science Foundation of China(U21A20313,22222807)。
文摘For living anionic polymerization(LAP),solvent has a great influence on both reaction mechanism and kinetics.In this work,by using the classical butyl lithium-styrene polymerization as a model system,the effect of solvent on the mechanism and kinetics of LAP was revealed through a strategy combining density functional theory(DFT)calculations and kinetic modeling.In terms of mechanism,it is found that the stronger the solvent polarity,the more electrons transfer from initiator to solvent through detailed energy decomposition analysis of electrostatic interactions between initiator and solvent molecules.Furthermore,we also found that the stronger the solvent polarity,the higher the monomer initiation energy barrier and the smaller the initiation rate coefficient.Counterintuitively,initiation is more favorable at lower temperatures based on the calculated results ofΔG_(TS).Finally,the kinetic characteristics in different solvents were further examined by kinetic modeling.It is found that in benzene and n-pentane,the polymerization rate exhibits first-order kinetics.While,slow initiation and fast propagation were observed in tetrahydrofuran(THF)due to the slow free ion formation rate,leading to a deviation from first-order kinetics.
文摘This study involved the assessment of the MNI2SX/Def2TZVP/H_(2)O model chemistry to enhance the understanding of the structural composition of the marine peptide Hemiasterlin and its derivatives A and B used in cancer treatment.The Conceptual Density Functional theory was used in the calculation of molecular properties of the system chemical descriptors during the study.Integration of the active molecular regions into their respective Fukui functions was used in the selection of electrophilic and nucleophilic attacks.Additionally,the proposed correlation between global hardness and the pKa was used as the basis of deriving accurate predictions for the pKa values while a homology technique was used in the prediction of bioactivity and bioavailability scores of the peptides under investigation.
文摘Background:Chaetomorpha aerea,a marine green alga,has drawn attention because of its rich phytochemical constituents and therapeutic benefits.Using an integrated approach that combined in vitro,in vivo,and in silico approaches,this work examined the antioxidant,anti-inflammatory,and antidiabetic qualities of acetone extract of C.aerea(AECA).Methods:Total phenolic and flavonoid concentrations of AECA were measured.Antioxidant activity was assessed using the DPPH and ABTS free radical scavenging assays.In vitro protein denaturation and in vivo carrageenan-induced paw edema models were employed to evaluate the anti-inflammatory potential,whereas antidiabetic activity was assessed using in vitroα-amylase inhibition and in vivo oral glucose tolerance test(OGTT).Molecular docking and ADME/T analysis were employed to further analyze bioactive compounds identified using gas chromatography–mass spectrometry(GC–MS).Result:Antioxidant activity demonstrated a minimum inhibitory concentration(IC_(50))of 107.44μg/mL for DPPH and 118.23μg/mL for ABTS.In vitro anti-inflammatory assays indicated a suppression of protein denaturation at a concentration of 102μg/mL(IC_(50)),where AECA(400 mg/kg)resulted in a 27%reduction in paw edema at 6 h in the mouse model.In vitro antidiabetic test indicatedα-amylase inhibition with an IC_(50) value of 70.72μg/mL,and in the OGTT,a significant lowering of blood glucose was recorded at 120 min in mice.Strong binding affinities were observed for stigmasta-5,24(28)-dien-3-ol,identified using GC–MS,with values of−9.9 kcal/mol forα-amylase and−8.0 kcal/mol for cyclooxygenase-2.Conclusion:C.aerea serves as an effective natural remedy for oxidative stress,inflammation,and hyperglycemia.These findings advocate for further clinical and mechanistic investigations to optimize therapeutic efficacy.
基金supported by the National Key Research and Development Program of China(2023YFB3307800)National Natural Science Foundation of China(62394343,62373155)+2 种基金Major Science and Technology Project of Xinjiang(No.2022A01006-4)State Key Laboratory of Industrial Control Technology,China(Grant No.ICT2024A26)Fundamental Research Funds for the Central Universities.
文摘Deep Learning has been widely used to model soft sensors in modern industrial processes with nonlinear variables and uncertainty.Due to the outstanding ability for high-level feature extraction,stacked autoencoder(SAE)has been widely used to improve the model accuracy of soft sensors.However,with the increase of network layers,SAE may encounter serious information loss issues,which affect the modeling performance of soft sensors.Besides,there are typically very few labeled samples in the data set,which brings challenges to traditional neural networks to solve.In this paper,a multi-scale feature fused stacked autoencoder(MFF-SAE)is suggested for feature representation related to hierarchical output,where stacked autoencoder,mutual information(MI)and multi-scale feature fusion(MFF)strategies are integrated.Based on correlation analysis between output and input variables,critical hidden variables are extracted from the original variables in each autoencoder's input layer,which are correspondingly given varying weights.Besides,an integration strategy based on multi-scale feature fusion is adopted to mitigate the impact of information loss with the deepening of the network layers.Then,the MFF-SAE method is designed and stacked to form deep networks.Two practical industrial processes are utilized to evaluate the performance of MFF-SAE.Results from simulations indicate that in comparison to other cutting-edge techniques,the proposed method may considerably enhance the accuracy of soft sensor modeling,where the suggested method reduces the root mean square error(RMSE)by 71.8%,17.1%and 64.7%,15.1%,respectively.
基金financial support from the National Key Research and Development Program of China(2016YFB0600305)National Natural Science Foundation of China(21808153,22078220)。
文摘The low-temperature coal tar contains a considerable number of oxygen-containing compounds,which results in poor quality.The catalytic hydrodeoxygenation of oxygen-containing compound to an added-value chemical compound is one of the most efficient methods to upgrade coal tar.In this study,density functional theory calculations are employed to assess and analyze in detail the hydrodeoxygenation of dibenzofuran,as a model compound of coal tar,on the Ni(111)surface.The obtained results indicate that dibenzofuran can be firstly hydrogenated to tetra hy d rod i be nzofura n and hexahydfodibenzofufan.The five-membered-ring opening reaction of tetrahydrodibenzofuran is more straightforward than that of hexahydrodibenzofuran(Ea=0.71 eV vs.1.66 eV).Then,both pathways generate an intermediate 2-cyclohexylphenoxy compound.One part of 2-cyclohexylphenoxy is hydrogenated to 2-cyclohexylphenol and consecutively hydrogenated to cyclohexylcyclohexanol,and another part is directly hydrogenated to cyclohexylcyclohexanone.The hydrogenated intermediates of2-cyclohexylphenol have higher deoxygenation barriers than 2-cyclohexylphenol and cyclohexylcy clohexanol.During the hydrogenation process of cyclohexylcyclohexanone to cyclohexylcyclohexanol,the intermediate 26,formed by adding H to O atom of cyclohexylcyclohexanone,exhibits the lowest deoxygenation barrier of 1.08 eV.High hydrogen coverage may promote the hydrogenation of tetrahydrodibenzofuran,hexahydrodibenzofuran,and intermediate 26 to generate dodecahydrodibenzofuran and cyclohexylcyclohexanol.This dibenzofuran hydrodeoxygenation reaction mechanism corroborates well with previous experimental results and provides a theoretical basis for further optimization of the design of nickel-based catalysts.
基金support of the National Natural Science Foundation of China(22078359,21276275).
文摘N-alkyl imidazolium carbonate ionic liquids were employed to separate and recover naphthenic acid from model oils.The effects of the cationic and anionic structures of ionic liquids and operating conditions on the deacidification performance were investigated.The deacidification performance of traditional organic solvents was also investigated for comparison.The results indicated that the naphthenic acid could be completely removed from the model oil with a small mass ratio of ionic liquid to oil.The extracted naphthenic acid was regenerated with a recovery of up to 92%.In addition,imidazolium carbonate ionic liquids could be successfully regenerated and recycled.The mechanism of interaction between imidazole ionic liquids and the naphthenic acid molecules were explained by Gauss calculation.
基金supported by grants from the National Natural Science Foundation of China(91132303,30830035)the National Basic Research Development Program of China (2011CBA00408)the China Postdoctoral Science Foundation(2012M511105)
文摘Ion channels,as membrane proteins,are the sensors of the cell.They act as the first line of communication with the world beyond the plasma membrane and transduce changes in the external and internal environments into unique electrical signals to shape the responses of excitable cells.Because of their importance in cellular communication,ion channels have been intensively studied at the structural and functional levels.Here,we summarize the diverse approaches,including molecular and cellular,chemical,optical,biophysical,and computational,used to probe the structural and functional rearrangements that occur during channel activation（or sensitization）,inactivation（or desensitization）,and various forms of modulation.The emerging insights into the structure and function of ion channels by multidisciplinary approaches allow the development of new pharmacotherapies as well as new tools useful in controlling cellular activity.
基金supported by the National Natural Science Foundation of China(52270027,52170037,and U20A20322)the Science and Technology Program of Jilin Province(20210201066GX)+1 种基金Scientific research project of Ecological Environment Department of Jilin Province(2023-05)Jilin Provincial Science and Technology Department Science and Technology Innovation and Entrepreneurship outstanding talent program for young and middle-aged(20230508051RC).
文摘Metal–organic frameworks(MOFs)are highly promising porous materials known for their exceptional porosity,extensive surface area,and customizable pore structures,making them an ideal solution for hydrogen storage.However,most MOFs research remains confined to the laboratory,lacking practical applications.To address this,the author proposes a shift towards practical applications,the creation of a comprehensive MOFs database,alignment of synthesis with practical considerations,and diversification of MOFs applications.These steps are crucial for harnessing the full potential of MOFs in real-world energy challenges.
文摘Advances in computational chemistry have greatly increased its effectiveness and attractiveness as an emerging adjunct to experimental chemistry but also as an independent research field. This work studied some basic bonding Parameters, geometry, Uv-Visible spectra, HOMO-LUMO and harmonic vibrational frequencies of Quinoline were investigated by using density functional theory (DFT/6-31+ (d, p)) methods. The calculated wave numbers (B3LYP) agree properly with the determined wave numbers. The results obtained are then as compared with experimental statistics in which available. The structural parameters;thermochemistry, rotational constants, IR spectra and frequencies, bond distances, angles and dipole moment were obtained from the optimized stable geometries of the compound. The computed optimized geometric bond lengths and bond angles show good agreement with experimental data of the title compound. The calculated HOMO and LUMO energies indicate that charge transfer occurs within the molecule.
文摘Possible structures of La 2C 2 were studied and proposed by use of density functional theory. All proposed isomers are planar. The results indicate that the structure with the lowest symmetry ( C 1) is the most stable. Linear isomers are not favored .
基金supported by the Shanxi Province Science Foundation for Youth(202303021212150)1331 Engineering of Shanxi Province,Research Grants Council of Hong Kong(CityU 11306517,11305919,and 11308620)National Natural Science Foundation of ChinaeResearch Grants Council of Hong Kong Joint Research Scheme N_CityU104/19.
文摘Lithium-sulfur(Li-S)batteries are regarded as one of the most promising next-generation energy storage systems due to their high theoretical specific energy density and low cost.However,serious shuttle effect and sluggish lithium polysulfides(LiPSs)redox kinetics severely impede the practical application of Li-S batteries.Employing polar sulfur hosts is an effective strategy to alleviate the above problems.Herein,the potential of two-dimensional(2D)Ti_(2)B-based sulfur hosts for Li-S batteries was comprehensively explored using first-principles calculations.The results show that functional groups of Ti_(2)B can significantly modulate its structural properties,thus affecting its interaction with sulfurcontaining species.Among S,Se,F,Cl,and Br elements,Ti_(2)B terminated with S and Se atoms possess stronger adsorption capability towards soluble Li_(2)S_(8),Li_(2)S_(6),and Li_(2)S_(4),obviously stronger than organic electrolytes,which indicates that they can completely suppress the shuttle effect.Besides,Ti_(2)BS_(2)and Ti_(2)BSe_(2)can powerfully expedite the electrochemical conversion of LiPSs.Moreover,the decomposition energy barrier of Li_(2)S and diffusion energy barrier of single Li ion on them are also fairly low,manifesting their excellent catalytic performance towards the oxidation of Li_(2)S.Finally,Ti_(2)BS_(2)and Ti_(2)BSe_(2)always keep metallic conductivity during the whole charge/discharge process.Taking all this into account,Ti_(2)BS_(2)and Ti_(2)BSe_(2)are proposed as promising bifunctional sulfur hosts for Li-S batteries.Our results suggest that increasing the proportion of S and Se groups during the synthesis of Ti_(2)B monolayers is greatly helpful for obtaining high-performance Li-S batteries.Besides,our work not only reveals the huge potential of 2D transition metal borides in Li-S batteries,but also provides insightful guidance for the design and screening of new efficient sulfur cathodes.
基金supported by the Provincial Innovation and Entrepreneurship Training Program of Jiangsu Province(No.201910319079Y)。
文摘OX_(2)(X=halogen)molecules was studied theoretically.Calculation results show that delocalizedπ_(3)^(6) bonds exist in their electronic structures and O atoms adopt the sp^(2) type of hybridization,which violates the prediction of the valence shell electron pair repulsion theory of sp^(3) type.Delocalization stabilization energy is proposed to measure the contribution of delocalizedπ_(3)^(6) bond to energy decrease and proves to bring extra-stability to the molecule.These phenomena can be summarized as a kind of coordinating effect.
基金supported by the National Natural Science Foundation of China(22322304,22273092,22373095)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0450101)+2 种基金the Innovation Program for Quantum Science and Technology(2021ZD0303306)the USTC Tang ScholarThe authors wish to acknowledge the Supercomputing Center of the USTC for providing computational resources.
文摘The achievement of electrical spin control is highly desirable.One promising strategy involves electrically mod-ulating the Rashba spin orbital coupling effect in materials.A semiconductor with high sensitivity in its Rashba constant to external electric fields holds great potential for short channel lengths in spin field-effect transistors,which is crucial for preserving spin coherence and enhancing integration density.Hence,two-dimensional(2D)Rashba semiconductors with large Rashba constants and significant electric field responses are highly desirable.Herein,by employing first-principles calculations,we design a thermodynamically stable 2D Rashba semiconductor,YSbTe_(3),which possesses an indirect band gap of 1.04 eV,a large Rashba constant of 1.54 eV·Åand a strong electric field response of up to 4.80 e·Å^(2).In particular,the Rashba constant dependence on the electric field shows an unusual nonlinear relationship.At the same time,YSbTe_(3)has been identified as a 2D ferroelectric material with a moderate polarization switching energy barrier(~0.33 eV per formula).By changing the electric polarization direction,the Rashba spin texture of YSbTe_(3)can be reversed.These out-standing properties make the ferroelectric Rashba semiconductor YSbTe_(3)quite promising for spintronic applications.
文摘Tetranitrodiazidoacetylhexaazaisowurtzitane (TNDAIW) is a novel polyazapolycyclic caged polyazidonitramine explosive first synthesized in our laboratory. Two possible conformers of TNDAIW with C_s symmetry were fully optimized using the HF/6-31G(d) level of theory. TNDAIW with the optimized geometries probably exists, and is predicted to be more stable than epsilon-hexanitrohexaazoisowurtzitane (epsilon-CL-20) based on the lengths of N-N, C-C and C-N bonds. The impact and shock sensitivities are lower for the possible conformers of TNDAIW than those for epsilon-CL-20. TNDAIW with the optimized possible conformers is estimated to be a promising novel high energy density explosive.
基金The Alabama Supercomputer Authority is gratefully acknowledged for a grant of computer time on the SGI Altix in Huntsville, AL. This work was supported by the National Science Foundation （NSF/HBCU-UP grant 0505872）. SJ is supported by NSF/HBCU-UP as an undergraduate scholar. This work was also supported by the National Institutes of Health （NIHINCMHD 1P20MD000547-01） and the Petroleum Research Fund, administered by the American Chemical Society （PRF 43798-B6）. AH is supported by the NIH as an undergraduate scholar in the Minority Access to Research Careers program （NIH/NIGMS 2T34GM008167-22A 1）. The taxpayers of the state of Alabama in particular and the United States in general are gratefully acknowledged.
文摘Nitrogen molecules Nx have been the subject of much recent research because of their potential as high-energy materials. Many nitrogen molecules dissociate with very low barriers, including molecules such as acyclic N4 that are essentially unbound. A number of studies have reported the ability of heteroatoms to stabilize complex nitrogen molecules. In the present study, the energetic and electronic properties of scandium（Ⅰ） and titanium（Ⅱ） complexes with N2 and N4 are calculated and discussed. Dissociation energies and singlet-triplet energies are determined by theoretical calculations using second-order perturbation theory （MP2） in conjunction with the Dunning basis sets.
文摘In this study, the chiral separation mechanisms of Dansyl amino acids, including Dansyl-Leucine (Dans-Leu), Dansyl-Norleucine (Dans-Nor), Dansyl-Tryptophan (Dans-Trp) and Dansyl-Phenylalanine (Dans-Phe) binding to poly-sodium </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">N</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:Verdana;">-undecanoyl-(L)-Leucylvalinate, poly (SULV), were investigated using molecular dynamics simulations. Micellar electrokinetic chromatography (MEKC) has previously shown that when separating the enantiomers of these aforementioned Dansyl amino acids, the L-enantiomers bind stronger to poly (SULV) than the D-enantiomers. This study aims to investigate the molecular interactions that govern chiral recognition in these systems using computational methods. This study reveals that the computationally-calculated binding free energy values for Dansyl enantiomers binding to poly (SULV) are in agreement with the enantiomeric order produced in experimental MEKC studies. The L-enantiomers of Dans-Leu, Dans-Nor, Dans-Trp, and Dans-Phe binding to their preferred binding pockets in poly (SULV) yielded binding free energy values of </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">21.8938, </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">22.1763, </span><span style="font-family:Verdana;">-</span><span style="font-family:""><span style="font-family:Verdana;">21.3329 </span><span style="font-family:Verdana;">and </span></span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">13.3349 kJ</span><span style="font-family:Verdana;">·</span><span style="font-family:Verdana;">mol</span><sup><span style="font-family:Verdana;">-</span></sup><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;">, respectively. The D-enantiomers of Dans-Leu, Dans-Nor</span><span style="font-family:Verdana;">, Dans-Trp, and Dans-Phe binding to their preferred binding pockets in poly (SULV) yielded binding free energy values of </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">14.5811, </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">15.9457, </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">13.6408, and </span><span style="font-family:Verdana;">-</span><span style="font-family:""><span style="font-family:Verdana;">12.0959</span><b> </b><span style="font-family:Verdana;">kJ</span></span><span style="font-family:Verdana;">·</span><span style="font-family:Verdana;">mol</span><sup><span style="font-family:Verdana;">-</span></sup><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;">, respectively. Furthermore, hydrogen bonding analyses w</span><span style="font-family:Verdana;">ere</span><span style="font-family:Verdana;"> used to investigate and elucidate the molecular interactions that govern chiral recognition in these molecular systems.
基金supported by the National Natural Science Foundation of China(82302345)the Natural Science Foundation Key Project of Zhejiang Province(Z24C130012)。
文摘Continuous cortisol monitoring(CCM)is essential for stress management,providing physiological insights into psychology and physical health.However,promising platform for CCM urges the design of effective biorecognition moieties and the skin integration of sophisticated functions.Herein,we present a computationally-assisted wearable system for CCM(CWSCCM)that leverages cutting-edge interdisciplinary technologies of in-situ regenerative molecularly imprinted polymers(MIP),signal amplifier organic electrochemical transistor(OECT),iontophoresis-based sweat induction,and microfluidic sweat sampling.The highly integrated system incorporated with OECT biosensor enables in-situ MIP regeneration,and offers continuous approach for cortisol monitoring,with an ultra-low limit of detection of0.36 nmol/L.We validated the capability of the CWSCCM for long-term cortisol circadian rhythm monitoring in human participants,which shows superior sensitivity,selectivity,and continuous monitoring capabilities.In conclusion,we demonstrated how computational chemistry and OECT technology can extend the capabilities of current wearable CCM,which could potentially advance closed-loop therapeutics applications.
基金Fundamental Research Funds for the Central Universities(2023MS125)。
文摘Currently,the iron chromium redox flow battery(ICRFB)has become a research hotspot in the energy storage field owing to its low cost and easily-scaled-up.However,the activity of electrolyte is still ambiguous due to its complicated solution environment.Herein,we performed a pioneering investigation on the coordination behavior and transformation mechanism of Cr^(3+)in electrolyte and prediction of impurity ions impact through quantum chemistry computations.Based on the structure and symmetry of electrostatic potential distribution,the activity of different Cr^(3+)complex ions is confirmed as[Cr(H2O)5Cl]^(2+)>[Cr(H2O)4Cl2]+>[Cr(H2O)6]^(3+).The transformation mechanism between[Cr(H2O)6]^(3+)and[Cr(H2O)5Cl]^(2+)is revealed.We find the metal impurity ions(especially Mg^(2+))can exacerbate the electrolyte deactivation by reducing the transformation energy barrier from[Cr(H2O)5Cl]^(2+)(24.38 kcal mol^(−1))to[Cr(H2O)6]^(3+)(16.23 kcal mol^(−1)).The solvent radial distribution and mean square displacement in different solvent environments are discussed and we conclude that the coordination configuration limits the diffusivity of Cr^(3+).This work provides new insights into the activity of electrolyte,laying a fundamental sense for the electrolyte in ICRFB.
