The theoretical system of the quantitative coalfield exploration and the relevant quantitative evaluation system, as well as the mathematical models and quantitative indices and classification scheme have been prelimi...The theoretical system of the quantitative coalfield exploration and the relevant quantitative evaluation system, as well as the mathematical models and quantitative indices and classification scheme have been preliminarily established on the basis of having quantitatively investigated and classified such basic problems in the coal exploration as the geological structure and coal seam variation, the exploration type, the density of exploration net, in the light of materials accumulated in China over the past forty years, under the theoretical guidance of modern coal geology, applied mathematics and mathematical geology by means of the computer technique.展开更多
Chirality has garnered significant attention in the scientific community since its discovery by Louis Pasteur over a century ago.It has been showing a profound impact on chemical,biomedical,and materials sciences.Sign...Chirality has garnered significant attention in the scientific community since its discovery by Louis Pasteur over a century ago.It has been showing a profound impact on chemical,biomedical,and materials sciences.Significant progress has been made in controlling molecular chirality,as evidenced by the several Nobel Prizes in chemistry awarded in this area,particularly for advancements in the asymmetric catalytic synthesis of molecules with central and axial chirality.However,the exploration of new types of chirality has been largely stagnant for more than half a century,likely due to the complexity and challenges inherent in this field.In this work,we present the discovery of a novel type of chirality—staircase chirality as inspired by the design and synthesis of unnatural amino acid derivatives.The architecture of staircase chirality is characterized by 2 symmetrical phenyl rings anchored by a naphthyl pier,with the rings asymmetrically displaced due to the influence of chiral auxiliaries at their para positions.This unique staircase chiral framework has been thoroughly characterized using spectroscopic techniques,with its absolute configuration definitively confirmed by x-ray diffraction analysis.Remarkably,one of the staircase molecules exhibits 4 distinct types of chirality:central,orientational,turbo,and staircase chirality,a combination that has not been previously documented in the literature.Computational studies using density functional theory(DFT)calculations were conducted to analyze the relative energies of individual staircase isomers,and the results are in agreement with our experimental findings.We believe that this discovery will open up a new research frontier in asymmetric synthesis and catalysis,with the potential to make a substantial impact on the fields of chemistry,medicine,and materials science.展开更多
Current Situation and Problems of the Treatment in Advanced Prostate Cancer In recent years,the incidence of prostate cancer shows a rising trend in China with an increase of 70%and has been the first place in the gro...Current Situation and Problems of the Treatment in Advanced Prostate Cancer In recent years,the incidence of prostate cancer shows a rising trend in China with an increase of 70%and has been the first place in the growth rate of malignant tumor in the male reproductive system. Prostate cancer has become a serious threat to male senior’s health.Because of the application of展开更多
文摘The theoretical system of the quantitative coalfield exploration and the relevant quantitative evaluation system, as well as the mathematical models and quantitative indices and classification scheme have been preliminarily established on the basis of having quantitatively investigated and classified such basic problems in the coal exploration as the geological structure and coal seam variation, the exploration type, the density of exploration net, in the light of materials accumulated in China over the past forty years, under the theoretical guidance of modern coal geology, applied mathematics and mathematical geology by means of the computer technique.
基金support from the Robert A.Welch Foundation[D-1361-20210327,USA(G.L.)and D-2108-20220331(R.L.)]the National Natural Science Foundation of China(Nos.22071102 and 91956110).
文摘Chirality has garnered significant attention in the scientific community since its discovery by Louis Pasteur over a century ago.It has been showing a profound impact on chemical,biomedical,and materials sciences.Significant progress has been made in controlling molecular chirality,as evidenced by the several Nobel Prizes in chemistry awarded in this area,particularly for advancements in the asymmetric catalytic synthesis of molecules with central and axial chirality.However,the exploration of new types of chirality has been largely stagnant for more than half a century,likely due to the complexity and challenges inherent in this field.In this work,we present the discovery of a novel type of chirality—staircase chirality as inspired by the design and synthesis of unnatural amino acid derivatives.The architecture of staircase chirality is characterized by 2 symmetrical phenyl rings anchored by a naphthyl pier,with the rings asymmetrically displaced due to the influence of chiral auxiliaries at their para positions.This unique staircase chiral framework has been thoroughly characterized using spectroscopic techniques,with its absolute configuration definitively confirmed by x-ray diffraction analysis.Remarkably,one of the staircase molecules exhibits 4 distinct types of chirality:central,orientational,turbo,and staircase chirality,a combination that has not been previously documented in the literature.Computational studies using density functional theory(DFT)calculations were conducted to analyze the relative energies of individual staircase isomers,and the results are in agreement with our experimental findings.We believe that this discovery will open up a new research frontier in asymmetric synthesis and catalysis,with the potential to make a substantial impact on the fields of chemistry,medicine,and materials science.
基金Supported by the National Natural Science Foundation of China(No.30873268)
文摘Current Situation and Problems of the Treatment in Advanced Prostate Cancer In recent years,the incidence of prostate cancer shows a rising trend in China with an increase of 70%and has been the first place in the growth rate of malignant tumor in the male reproductive system. Prostate cancer has become a serious threat to male senior’s health.Because of the application of
