研究旨在探讨环二肽Cyclo(Leu-Pro)对植物乳杆菌生长的影响。该研究以植物乳杆菌(Lactobacillus Plantarum T1)为研究对象,采用高效液相色谱法初步定性定量植物乳杆菌T1发酵液中的Cyclo(Leu-Pro),然后将植物乳杆菌T1分别接种于不含或含...研究旨在探讨环二肽Cyclo(Leu-Pro)对植物乳杆菌生长的影响。该研究以植物乳杆菌(Lactobacillus Plantarum T1)为研究对象,采用高效液相色谱法初步定性定量植物乳杆菌T1发酵液中的Cyclo(Leu-Pro),然后将植物乳杆菌T1分别接种于不含或含不同质量浓度(0.5、1、5、10μg/mL)Cyclo(Leu-Pro)的MRS肉汤培养基中培养18 h,采用96孔法和平板计数法测定不同培养条件下植物乳杆菌T1的生长曲线和活菌数。结果表明:不同质量浓度的Cyclo(Leu-Pro)对植物乳杆菌T1的生长均有明显的促生长作用,其中,1μg/mL Cyclo(Leu-Pro)的促生长效果最佳,可将活菌数提高到8.73×10^(10) CFU/mL,相比于对照组提高了一个数量级。在不同胁迫条件下,1μg/mL Cyclo(Leu-Pro)能使植物乳杆菌T1的延滞期缩短、生长速度提高,其活菌数和生物量显著增加(P<0.05)。综上所述,Cyclo(Leu-Pro)促进了植物乳杆菌T1的生长,增强了其抗胁迫能力。这将有利于植物乳杆菌T1作为发酵剂在食品发酵领域的应用。展开更多
This is a prospective interventional clinical study evaluating intraocular inflammation developed after Ultrasound Cyclo Plasty(UCP) for the treatment of glaucoma. Eighteen eyes of 18 patients were treated with UCP se...This is a prospective interventional clinical study evaluating intraocular inflammation developed after Ultrasound Cyclo Plasty(UCP) for the treatment of glaucoma. Eighteen eyes of 18 patients were treated with UCP second-generation probes(Eye OP1). After treatment, the mean intraocular pressure(IOP) significantly decreased from 26.8±7.2 to 18.8±6.1 mm Hg at day 1 and to 14.7±3.4 mm Hg at month 6(all P<0.001). Mean laser flare-cell photometry value steeply increased after surgery from 12.1±7.5 to 64.1±53.9 ph/ms(P=0.001) at day 1, and then progressively decreased to respectively 60.6±49.7 at day 7, 43.5±38.5 at day 14 and 28.2±18.3 at month 1(all P<0.05), returning at levels similar to baseline ones at month 3 and month 6(respectively 16.7±6.2 and 12.8±10.2, both P>0.05). A significant negative correlation was found between postoperative increase of aqueous flare values and anterior chamber depth(R=-0.568, P=0.014). This timeframe may be considered reasonable for repeating UCP treatment, when required.展开更多
A new cyclodipeptide, cyclo(phenylalanyl-N-methyltyrosyl) 1, was isolated from the mycelial solid cultures of Geotrichum candidum. Its structure was elucidated by spectroscopic methods. The antifungal activity of the ...A new cyclodipeptide, cyclo(phenylalanyl-N-methyltyrosyl) 1, was isolated from the mycelial solid cultures of Geotrichum candidum. Its structure was elucidated by spectroscopic methods. The antifungal activity of the new compound against Peronophythora litchii was assessed by microplate Alamar blue assay (MABA).展开更多
Cyclocarbon fully consists of sp-hybridized carbon atoms,which shows quite unusual electronic and geometric structures compared to common molecules.In this work,we systematically studied strain energy(SE)of cyclocarbo...Cyclocarbon fully consists of sp-hybridized carbon atoms,which shows quite unusual electronic and geometric structures compared to common molecules.In this work,we systematically studied strain energy(SE)of cyclocarbons of different sizes using regression analysis method based on electronic energies evaluated at the very accurate DLPNO-CCSD(T)/ccp VTZ theoretical level.In addition,ring strain of two systems closely related to cyclocarbon,boron nitride(BN)ring,and cyclic polyacetylene(c-PA),is also explored.Very ideal relationships between SE and number of repeat units(n)are built for cyclo[2n]carbon,B_(n)N_(n),and[2n]c-PA as SE=555.0·n^(-1),145.1·n^(-1),and 629.8·n^(-1)kcal·mol^(-1),respectively,and the underlying reasons of the difference and similarity in their SEs are discussed from electronic structure perspective.In addition,force constant of harmonic potential of C-C-C angles in cyclocarbon is derived based on SE values,the result is found to be 56.23 kcal·mol^(-1)·rad^(-2).The possibility of constructing homodesmotic reactions to calculate SEs of cyclocarbons is also explored in this work,although this method is far less rigorous than the regression analysis method,its result is qualitatively correct and has the advantage of much lower computational cost.In addition,comparisons show thatωB97XD/def2-TZVP is a good inexpensive alternative to the DLPNO-CCSD(T)/cc-p VTZ for evaluating energies used in deriving SE,while the popular and very cheap B3LYP/6-31G(d)level should be used with caution for systems with global electron conjugation such as c-PA.展开更多
An easy and mild way to construct 13-hydroxy-9,15-cyclo GA skeletons was reported and it could be used as a general protocol in the synthesis of GAs with this structure.
Cyclo[18]carbon has received considerable attention thanks to its novel geometric configuration and special electronic structure.Superalkalis have low ionization energy.Doping a superalkali in cyclo[18]carbon is an ef...Cyclo[18]carbon has received considerable attention thanks to its novel geometric configuration and special electronic structure.Superalkalis have low ionization energy.Doping a superalkali in cyclo[18]carbon is an effective method to improve the optical properties of the system because considerable electron transfer occurs.In this paper,the geometry,bonding properties,electronic structure,absorption spectrum,and nonlinear optical(NLO)properties of superalkaline M_(3)O(M=Li,Na)-doped cyclo[18]carbon were studied by using density functional theory.M_(3)O and the C_(18) rings are not coplanar.The C_(18) ring still exhibits alternating long and short bonds.The charge transfer between M_(3)O and C_(18) forms stable[M_(3)O]+[C_(18)]-ionic complexes.C_(18)M_(3)O(M=Li,Na)shows striking optical nonlinearity,i.e.,their first-and second-order hyperpolarizability(βvec andγ||)increase considerably atλ=1907 nm and 1460 nm.展开更多
Treatment of 1,3-di- t -butylcyclopentadiene with rhodium trichloride in EtOH leads to the formation of binuclear half-sandwich complex [Cp t RhCl( μ -Cl)] 2 (1) (Cp t = η 5- t Bu 2C 5H 3) which reacts with trimethy...Treatment of 1,3-di- t -butylcyclopentadiene with rhodium trichloride in EtOH leads to the formation of binuclear half-sandwich complex [Cp t RhCl( μ -Cl)] 2 (1) (Cp t = η 5- t Bu 2C 5H 3) which reacts with trimethylphosphine to give Cp t Rh(PMe 3)Cl 2(2) in high yield. 2 reacts with ammonium polysulfide, (NH 4) 2S x to give cyclooligosulfido half-sandwich complexes Cp t Rh(PMe 3)(S n )( n =4(4a),6(4b)). Desulfurization of 4b by excess PPh 3 results in cyclotetrasulfido product 4a, while 4a takes up sulfur from polysulfide to convert cyclohexasulfido product 4b. The reaction of 2 with Et 4NI gives diiodide complex 3 which is determined by single crystal X-ray crystallographic analysis.展开更多
Carbon materials have long been a subject of study, offering diverse properties based on their hybridized structures. Except sp^(2)-hybridized graphene and carbon nanotubes, the focus on sp^(1)-hybridized carbon chain...Carbon materials have long been a subject of study, offering diverse properties based on their hybridized structures. Except sp^(2)-hybridized graphene and carbon nanotubes, the focus on sp^(1)-hybridized carbon chains has garnered significant interest due to its unique predicted properties, despite limitations in research and development stemming from its high reactivity. This comprehensive review summaries recent advancements in synthetic methodologies and characterization of the sp^(1)-hybridized carbon chains, encompassing linear carbon chains and cyclo[n]carbons. The review traces significant milestones in synthesis and offers a thorough overview of various properties on linear and cyclic carbon chains, from their initial discovery to recent development. The advancing synthetic methods have led to practical breakthroughs, transitioning theoretical concepts into tangible carbon-chain materials. However, challenges persist in achieving controlled and scalable preparation due to the high reactivity associated with sp^(1)-hybridization. Future research prospects focus on fundamental studies, such as exploring the transition length from polyyne to carbyne and experimentally determining the properties of single carbon chains.This review underscores both the progress made and the compelling avenues for future exploration in the dynamic field of sp^(1)-hybridized carbon chains.展开更多
Carbon is an element with exceptional capacity for structural reinvention.This interesting characteristic,which has captivated numerous scientists in different areas of chemistry,is more than evident when the differen...Carbon is an element with exceptional capacity for structural reinvention.This interesting characteristic,which has captivated numerous scientists in different areas of chemistry,is more than evident when the different allotropes of carbon are considered[1].From the rigidity of diamond to the layered structure of graphite,from the curved architectures of fullerenes and carbon nanotubes to the two-dimensional sheets of graphene,carbon relentlessly fascinates chemists with its versatility.Each of these carbon allotropes arises because carbon atoms can hybridize their orbitals in different ways(i.e.,sp^(3),sp^(2),and sp)and combinations.展开更多
文摘This is a prospective interventional clinical study evaluating intraocular inflammation developed after Ultrasound Cyclo Plasty(UCP) for the treatment of glaucoma. Eighteen eyes of 18 patients were treated with UCP second-generation probes(Eye OP1). After treatment, the mean intraocular pressure(IOP) significantly decreased from 26.8±7.2 to 18.8±6.1 mm Hg at day 1 and to 14.7±3.4 mm Hg at month 6(all P<0.001). Mean laser flare-cell photometry value steeply increased after surgery from 12.1±7.5 to 64.1±53.9 ph/ms(P=0.001) at day 1, and then progressively decreased to respectively 60.6±49.7 at day 7, 43.5±38.5 at day 14 and 28.2±18.3 at month 1(all P<0.05), returning at levels similar to baseline ones at month 3 and month 6(respectively 16.7±6.2 and 12.8±10.2, both P>0.05). A significant negative correlation was found between postoperative increase of aqueous flare values and anterior chamber depth(R=-0.568, P=0.014). This timeframe may be considered reasonable for repeating UCP treatment, when required.
文摘A new cyclodipeptide, cyclo(phenylalanyl-N-methyltyrosyl) 1, was isolated from the mycelial solid cultures of Geotrichum candidum. Its structure was elucidated by spectroscopic methods. The antifungal activity of the new compound against Peronophythora litchii was assessed by microplate Alamar blue assay (MABA).
文摘Cyclocarbon fully consists of sp-hybridized carbon atoms,which shows quite unusual electronic and geometric structures compared to common molecules.In this work,we systematically studied strain energy(SE)of cyclocarbons of different sizes using regression analysis method based on electronic energies evaluated at the very accurate DLPNO-CCSD(T)/ccp VTZ theoretical level.In addition,ring strain of two systems closely related to cyclocarbon,boron nitride(BN)ring,and cyclic polyacetylene(c-PA),is also explored.Very ideal relationships between SE and number of repeat units(n)are built for cyclo[2n]carbon,B_(n)N_(n),and[2n]c-PA as SE=555.0·n^(-1),145.1·n^(-1),and 629.8·n^(-1)kcal·mol^(-1),respectively,and the underlying reasons of the difference and similarity in their SEs are discussed from electronic structure perspective.In addition,force constant of harmonic potential of C-C-C angles in cyclocarbon is derived based on SE values,the result is found to be 56.23 kcal·mol^(-1)·rad^(-2).The possibility of constructing homodesmotic reactions to calculate SEs of cyclocarbons is also explored in this work,although this method is far less rigorous than the regression analysis method,its result is qualitatively correct and has the advantage of much lower computational cost.In addition,comparisons show thatωB97XD/def2-TZVP is a good inexpensive alternative to the DLPNO-CCSD(T)/cc-p VTZ for evaluating energies used in deriving SE,while the popular and very cheap B3LYP/6-31G(d)level should be used with caution for systems with global electron conjugation such as c-PA.
基金partly supported by the Natural Science Foundation of Yunnan Provence.(No.2000B0001 R).
文摘An easy and mild way to construct 13-hydroxy-9,15-cyclo GA skeletons was reported and it could be used as a general protocol in the synthesis of GAs with this structure.
基金Project supported by the Natural Science Foundation of Anhui Province(Grant No.1908085MA12)the National Natural Science Foundation of China(Grant No.21703222)。
文摘Cyclo[18]carbon has received considerable attention thanks to its novel geometric configuration and special electronic structure.Superalkalis have low ionization energy.Doping a superalkali in cyclo[18]carbon is an effective method to improve the optical properties of the system because considerable electron transfer occurs.In this paper,the geometry,bonding properties,electronic structure,absorption spectrum,and nonlinear optical(NLO)properties of superalkaline M_(3)O(M=Li,Na)-doped cyclo[18]carbon were studied by using density functional theory.M_(3)O and the C_(18) rings are not coplanar.The C_(18) ring still exhibits alternating long and short bonds.The charge transfer between M_(3)O and C_(18) forms stable[M_(3)O]+[C_(18)]-ionic complexes.C_(18)M_(3)O(M=Li,Na)shows striking optical nonlinearity,i.e.,their first-and second-order hyperpolarizability(βvec andγ||)increase considerably atλ=1907 nm and 1460 nm.
基金Financial support by the National Natural Science Foundation of China and by the Special Funds for Major State Basic Research Projects(G1999064800)is gratefully acknowledged.
文摘Treatment of 1,3-di- t -butylcyclopentadiene with rhodium trichloride in EtOH leads to the formation of binuclear half-sandwich complex [Cp t RhCl( μ -Cl)] 2 (1) (Cp t = η 5- t Bu 2C 5H 3) which reacts with trimethylphosphine to give Cp t Rh(PMe 3)Cl 2(2) in high yield. 2 reacts with ammonium polysulfide, (NH 4) 2S x to give cyclooligosulfido half-sandwich complexes Cp t Rh(PMe 3)(S n )( n =4(4a),6(4b)). Desulfurization of 4b by excess PPh 3 results in cyclotetrasulfido product 4a, while 4a takes up sulfur from polysulfide to convert cyclohexasulfido product 4b. The reaction of 2 with Et 4NI gives diiodide complex 3 which is determined by single crystal X-ray crystallographic analysis.
基金supported by National Natural Science Foundation of China (No. 52472059)Fundamental Research Funds for the Central Universities, Sun Yat-sen University (No. 22lgqb03)State Key Laboratory of Optoelectronic Materials and Technologies (No. OEMT-2022-ZRC-01)。
文摘Carbon materials have long been a subject of study, offering diverse properties based on their hybridized structures. Except sp^(2)-hybridized graphene and carbon nanotubes, the focus on sp^(1)-hybridized carbon chains has garnered significant interest due to its unique predicted properties, despite limitations in research and development stemming from its high reactivity. This comprehensive review summaries recent advancements in synthetic methodologies and characterization of the sp^(1)-hybridized carbon chains, encompassing linear carbon chains and cyclo[n]carbons. The review traces significant milestones in synthesis and offers a thorough overview of various properties on linear and cyclic carbon chains, from their initial discovery to recent development. The advancing synthetic methods have led to practical breakthroughs, transitioning theoretical concepts into tangible carbon-chain materials. However, challenges persist in achieving controlled and scalable preparation due to the high reactivity associated with sp^(1)-hybridization. Future research prospects focus on fundamental studies, such as exploring the transition length from polyyne to carbyne and experimentally determining the properties of single carbon chains.This review underscores both the progress made and the compelling avenues for future exploration in the dynamic field of sp^(1)-hybridized carbon chains.
文摘Carbon is an element with exceptional capacity for structural reinvention.This interesting characteristic,which has captivated numerous scientists in different areas of chemistry,is more than evident when the different allotropes of carbon are considered[1].From the rigidity of diamond to the layered structure of graphite,from the curved architectures of fullerenes and carbon nanotubes to the two-dimensional sheets of graphene,carbon relentlessly fascinates chemists with its versatility.Each of these carbon allotropes arises because carbon atoms can hybridize their orbitals in different ways(i.e.,sp^(3),sp^(2),and sp)and combinations.
