The relative conformer energies of glycine are evaluated by using a focal point analysis expressed as（HF→MP2→MP3→CCSD→CCSD（T））.The conformer abundances at various temperatures（298–500 K） are calculated base...The relative conformer energies of glycine are evaluated by using a focal point analysis expressed as（HF→MP2→MP3→CCSD→CCSD（T））.The conformer abundances at various temperatures（298–500 K） are calculated based on the relative energies and Boltzmann statistical thermostatistical analysis with and without considering internal hindered rotations.A comparison between the available Raman spectrum and the electron momentum spectrum confirms that the influence of rigid-rotor hindered rotation on the conformational proportions of glycine is considerable,especially for the IIIp structure.The conformational interconversions are discussed.It is found that with increasing temperature,the mole fraction of IIn keeps constant and Ip structure can convert into IVn and IIIp,leading to the decrease in the weight of Ip and the increase in the weights of IVn and IIIp conformers,which is in accordance with experimental observations.展开更多
The adsorption behaviors of glycine on diamond （001） are systematically investigated by first-principles calculations. We have considered all possible adsorption configurations without a surface dangling bond and gi...The adsorption behaviors of glycine on diamond （001） are systematically investigated by first-principles calculations. We have considered all possible adsorption configurations without a surface dangling bond and give a quantitative analysis for the relationship between the deviation of carbon bond angle and adsorption energy. We found that a smaller distortion of carbon covalent bond angle results in a more stable adsorption structure, and the most stable adsorption has a benzene-ringlike structure with the highest adsorption energy of 5. 11 eV per molecule and the minimum distortion of carbon covalent bond angle.展开更多
To evaluate the effect of intrathecal administration of glycine on the minimum alveolar concentration （MAC） of isoflurane in rats. Methods Intrathecal catheters were implanted in 40 adult male rats anesthetized wit...To evaluate the effect of intrathecal administration of glycine on the minimum alveolar concentration （MAC） of isoflurane in rats. Methods Intrathecal catheters were implanted in 40 adult male rats anesthetized with isoflurane. Baseline MAC of isoflurane was measured during the infusion of artificial cerebrospinal fluid （CSF） alone. Subsequently, 10, 40, 80, 160, and 300 mmol/L of glycine dissolved in artificial CSF were infused for two hours at the same rate as under control conditions, and MAC for isoflurane was re-determined. Results Intrathecal administration of glycine produced a significant, dose-dependent decrease in MAC for isoflurane （up to -65.2% ± 16. 2% ）. Conclusions Intrathecal administration of glycine decreases anesthetic requirement. This result supports the idea that glycine receptors may be important to the immobilizing effect of anesthetics that enhance glycine receptor function such as isoflurane.展开更多
The adsorption of L-alanine on Cu（111） surface is studied by means of scanning tunnelling microscopy under ultra-high vacuum conditions. The results show that the adsorbates are chemisorbed on the surface, and can f...The adsorption of L-alanine on Cu（111） surface is studied by means of scanning tunnelling microscopy under ultra-high vacuum conditions. The results show that the adsorbates are chemisorbed on the surface, and can form a two-dimensional gas phase, chain phase and solid phase, depending on deposition rate and amount. The adsorbed molecules can be imaged as individual protrusions and parallel chains in gas and chain phases respectively. It is also found that alanine can form （2 × 2） superstructure on Cu（111） and copper step facet to （110） directions in solid phase. On the basis of our scanning tunnelling microscopic images, a model is proposed for the Cu（111）（2 ×2）-alanine superstructure. In the model, we point out the close link between （110）-direction hydrogen bond chains with the same direction copper step faceting.展开更多
基金The financial support for this study by National Natural Science Foundation of China(No.30960242)National Basic Research Program of China(973 program)(No.2012CB720805)Training Project of Young Scientists of Jiangxi Province(Stars of Jing gang)is gratefully acknowledged.
基金Project supported by the Young Scientists Funds of the National Natural Science Foundation of China(Grant Nos.11404154 and 11304136)
文摘The relative conformer energies of glycine are evaluated by using a focal point analysis expressed as（HF→MP2→MP3→CCSD→CCSD（T））.The conformer abundances at various temperatures（298–500 K） are calculated based on the relative energies and Boltzmann statistical thermostatistical analysis with and without considering internal hindered rotations.A comparison between the available Raman spectrum and the electron momentum spectrum confirms that the influence of rigid-rotor hindered rotation on the conformational proportions of glycine is considerable,especially for the IIIp structure.The conformational interconversions are discussed.It is found that with increasing temperature,the mole fraction of IIn keeps constant and Ip structure can convert into IVn and IIIp,leading to the decrease in the weight of Ip and the increase in the weights of IVn and IIIp conformers,which is in accordance with experimental observations.
基金supported by the National Natural Science Foundation of China(Grant Nos.51272278,91323304,10774177,and 11374341)the National Basic Research Program of China(Grand No.2009CB930502)+2 种基金the Knowledge Innovation Project of Chinese Academy of Sciences(Grand No.KJCX2-EW-W02)the Fundamental Research Funds for the Central Universities of Ministry of Education of Chinathe Research Funds of Renmin University of China
文摘The adsorption behaviors of glycine on diamond （001） are systematically investigated by first-principles calculations. We have considered all possible adsorption configurations without a surface dangling bond and give a quantitative analysis for the relationship between the deviation of carbon bond angle and adsorption energy. We found that a smaller distortion of carbon covalent bond angle results in a more stable adsorption structure, and the most stable adsorption has a benzene-ringlike structure with the highest adsorption energy of 5. 11 eV per molecule and the minimum distortion of carbon covalent bond angle.
文摘To evaluate the effect of intrathecal administration of glycine on the minimum alveolar concentration （MAC） of isoflurane in rats. Methods Intrathecal catheters were implanted in 40 adult male rats anesthetized with isoflurane. Baseline MAC of isoflurane was measured during the infusion of artificial cerebrospinal fluid （CSF） alone. Subsequently, 10, 40, 80, 160, and 300 mmol/L of glycine dissolved in artificial CSF were infused for two hours at the same rate as under control conditions, and MAC for isoflurane was re-determined. Results Intrathecal administration of glycine produced a significant, dose-dependent decrease in MAC for isoflurane （up to -65.2% ± 16. 2% ）. Conclusions Intrathecal administration of glycine decreases anesthetic requirement. This result supports the idea that glycine receptors may be important to the immobilizing effect of anesthetics that enhance glycine receptor function such as isoflurane.
基金Supported by National Natural Science Foundation of China(No.3997023939800044)+1 种基金FoundationforUniversityKeyTeacherbytheMinistryofEducationofChinatheNationalProgramofBasicResearchofChina(G1999054000).
基金Supported by the National Basic Research Programme of China under Grant Nos 001CB610502 and 001CB610504, the National High Technology Development Program of China under Grant No 2004AA302Gll, the National Natural Science Foundation of China under Grant No 60271004, and the Key Project and the Program for New Century Excellent Talents in University of the Ministry of Education of China. 0ne of the authors （Ge Siping） wishes to thank Professor Q. Chen for her generous assistance.
文摘The adsorption of L-alanine on Cu（111） surface is studied by means of scanning tunnelling microscopy under ultra-high vacuum conditions. The results show that the adsorbates are chemisorbed on the surface, and can form a two-dimensional gas phase, chain phase and solid phase, depending on deposition rate and amount. The adsorbed molecules can be imaged as individual protrusions and parallel chains in gas and chain phases respectively. It is also found that alanine can form （2 × 2） superstructure on Cu（111） and copper step facet to （110） directions in solid phase. On the basis of our scanning tunnelling microscopic images, a model is proposed for the Cu（111）（2 ×2）-alanine superstructure. In the model, we point out the close link between （110）-direction hydrogen bond chains with the same direction copper step faceting.
