Prenatal alcohol exposure, especially during early pregnancy, can lead to fetal alcohol syndrome. The pharmacological and toxicological mechanisms of ethanol are related to the effects of ceramide In this study, we es...Prenatal alcohol exposure, especially during early pregnancy, can lead to fetal alcohol syndrome. The pharmacological and toxicological mechanisms of ethanol are related to the effects of ceramide In this study, we established an alcohol exposure model in wild-type mice and in knockout mice for the key enzyme involved in ceramide metabolism, sphingomyelin synthase 2. This model received daily intragastric administration of 25% ethanol, and pups were used at postnatal days 0, 7, 14, 30 for experiments. Serology and immunofluorescence staining found that ethanol exposure dose-dependently reduced blood sphingomyelin levels in two genotypes of pups, and increased neural cell proliferation and the number of new neurons in the hippocampal dentate gyrus. Western blot analysis showed that the relative expression level of protein kinase C e increased in two genotypes of pups after ethanol exposure. Compared with witd-type pups, the expression level of the important activator protein of the ceramide/ceramide-l-phosphate pathway, protein kinase C a, was reduced in the hippocampus of sphingomyelin synthase 2 knockouts. Our findings illustrate that ceramide is involved in alcohol-induced neural proliferation in the hippocampal dentate gyrus of pups after prenatal ethanol exposure, and the mechanism may be associated with increased ex- pression of protein kinase C a activating the ceramide/ceramide-l-phosphate pathway.展开更多
近些年,随着教育研究领域的国际交流与合作日益频繁而密切,美国教育研究协会（The American Educational Research Association,简称AERA）逐步进入了中国教育学者的视野,其一年一度的大会不仅吸引着大批的中国学者积极通过各种方式前...近些年,随着教育研究领域的国际交流与合作日益频繁而密切,美国教育研究协会（The American Educational Research Association,简称AERA）逐步进入了中国教育学者的视野,其一年一度的大会不仅吸引着大批的中国学者积极通过各种方式前往参会,在中国国内经常也会借势刮起一阵AERA旋风,媒体报道、专题介绍、学术探讨……不一而足。展开更多
Audiological use of the 40 Hz-ASSR (auditory steady state responses) could be valuable for objectivelyestimating the frequency-specific threshold in adults undergoing an expertise examination for medicolegal and/or co...Audiological use of the 40 Hz-ASSR (auditory steady state responses) could be valuable for objectivelyestimating the frequency-specific threshold in adults undergoing an expertise examination for medicolegal and/or compensation purposes. The present prospective study was set up to clarify the relationship between the thresholds obtained by cortical evoked response audiometry (CERA) and by 40 HzASSR, in the same ears, within a large homogeneous sample of 164 subjects (328 ears) with NIHL andwell documented exposure to noise. All these subjects claimed financial compensation for occupationalNIHL, and there was a suspicion of exaggeration of the reported NIHLs. ASSR thresholds show a goodcorrelation with the CERA thresholds. However, a systematic shift is noticed, ASSR thresholds being onaverage (1e2 e 3 kHz) 4.38 dB lower (i.e. showing less hearing loss) than CERA thresholds. Moreover, thebinaural multiple ASSR technique allows a considerable time gain when compared to the CERA.展开更多
Carnuba wax consists chiefly of myricyl cerotate (M<sub>W</sub> 817.4) and small quantities of free cerotic acid (C<sub>26</sub>H<sub>52</sub>O<sub>2</sub>, Mw 396.7) an...Carnuba wax consists chiefly of myricyl cerotate (M<sub>W</sub> 817.4) and small quantities of free cerotic acid (C<sub>26</sub>H<sub>52</sub>O<sub>2</sub>, Mw 396.7) and myricyl alcohol (C<sub>30</sub>H<sub>62</sub>O, mp 90°C). Of the two common extraction solvents, ethyl ether or petroleum ether, Lewkowitsch prefers the former. Concerning separation of phases, he advocates addition of small amounts of alcohol or caustic, and he also states that formation of a flocculant layer between the aqueous layer and the solvent does not interfere with the correct estimation of the unsaponifiable matter. These statements were not corroborated in the hands of this chemist. The “Unsaponifiable Matter” in oils or and fats, which consist mainly of hydrocarbons, sterols and aliphatic alcohols of high molecular mass that are not saponifiable by alkali hydroxides but are soluble in the ordinary fat solvents, and to products of saponification that are soluble in such solvents. Carnuba wax, a rather expensive wax, may be adulterated with less expensive paraffin by dishonest merchants. ASTM has a method for determining paraffinic material in carnuba wax. It uses heptanes at its boiling point to dissolve the wax, apply it to a silica gel column, and elute only the nonpolar (i.e. alkane) material. The method has the disadvantage of using a large volume of haptane, nor is it called for by either US Pharmacopeia/National Formulary (USP/NF) or Food Chemicals Codex (FCC). The test for unsaponifiable matter on pure carnuba wax will yield a result of 50.0% - 55.0%, while a higher result will betray the presence of paraffin adulterants.展开更多
Optimization Algorithm was developed for the simula ti on of ceramic grain growth at atomistic scale. Based on the coordination informa tion of different atoms, a structure of trident tree was applied to save large q ...Optimization Algorithm was developed for the simula ti on of ceramic grain growth at atomistic scale. Based on the coordination informa tion of different atoms, a structure of trident tree was applied to save large q uantities data, so as to solve the problems of large data information and long r unning time. For every atom a binary tree was firstly formed according to the X coordination of atom. If the values of X coordination were the same, the middle sub-tree of first layer formed then a binary tree according to the Y coordinati on of atom. If the values of Y coordination were also the same, the middle sub- tree of second layer formed then a binary tree according to the Z coordination o f atom. In this way the speed of whole program is enhanced obviously. In order t o reduce memory, in this structure only need to store the exterior atoms’ infor mation, an integer is used to store the interior atoms’ information. If other a toms take up an atom’s all adjacent positions, this atom will be deleted in the data structure, for all the adjacent positions’ atoms, the integer’s relative bit will be set 1 to denote that there is an atom in this position but not be s tored in the trident tree. When an outside atom is deleted, for all the bits tha t are set 1,an atom will be added to the trident tree as an outside atom for the relative positions. And for this new added atom, the integer’s relative bi t of all the adjacent position’s atoms should be set 0 to denote that there is no interior atom in this position. In this way, if there are n 3 atoms, onl y need to store 6n 2 quantity’s atoms’ information. Large quantity of mem ory space can then be saved.展开更多
Abstract In recent years, our research group has developed and studied new rare-earth doped materials for the promising technology of solid-state laser cooling, which is based on anti-stokes fluorescence. To the best ...Abstract In recent years, our research group has developed and studied new rare-earth doped materials for the promising technology of solid-state laser cooling, which is based on anti-stokes fluorescence. To the best of our knowledge, our group is the only one in Canada leading the research into the properties of nanoparticles, glasses and glass-ceramics for optical refrigeration appli- cations. In the present work, optical properties of 50GeO2- 30PbF2-18PbO-2YbF3 glass-ceramics for laser cooling are presented and discussed as a function of crystallization temperature. Spectroscopic results show that samples have near infrared photoluminescence emission due to the 2F5/2 - 2F7/2 Yb3＋ transition, centered at -1016 nm with an excitation wavelength of 920 nm or 1011 nm, and the highest photoluminescence emission efficiency occurs for heat-treatment for 5 h at 350℃. The internal photolumi- nescence quantum yield varies between 99% and 80%, depending on the temperature of heat-treatment, being the most efficient under 1011 nm excitation. The 2F5/2 lifetime increases from 1.472 to 1.970 ms for heat treatments at 330℃ to 350℃, respectively, due to energy trapping and the low phonon energy of the nanocrystals. The sample temperature dependence was measured with a fiber Bragg grating sensor, as a function of input pump laser wavelength and processing temperature. These measure- ments show that the heating process approaches near zero for an excitation wavelength between 1020 and 1030 nm, which is an indication that phonons are removed effectivelly from the glass-ceramic materials, and they can be used for optical laser cooling applications. On theother hand, the temperature increase as a function of input laser power into samples remains constant between 920 and 980 nm wavelength excitation, a temperature variation of 36 K/W （temperature of 58℃/W） was attained under excitation at 950 nm, showing a possible use for biomedical applications to be explored.展开更多
Coastal erosion on islands is increasing due to sea level rise,frequent extreme events,and anthropogenic activities.However,studies on the multifactorial coastal erosion risk and the vulnerability of islands are limit...Coastal erosion on islands is increasing due to sea level rise,frequent extreme events,and anthropogenic activities.However,studies on the multifactorial coastal erosion risk and the vulnerability of islands are limited.In this study,the Coastal Erosion Risk Assessment(CERA)method was applied for the first time to the study area in China to assess the erosion risk on the coast of Hainan Island;to explore the effects of coastal ocean dynamics,sediment movement characteristics,and anthropogenic construction;and to discuss the suitability of the method and countermeasures for coastal protection.The results show that the coast of Hainan Island shows high sensitivity,high value,low exposure,and moderate erosion.The whole island showed high vulnerability but low erosion risk,with the eastern region being more affected by erosion,particularly the eastern side of Wulong Port and Yalin Bay in Wenchang,and the shore section of Yalong Bay in Sanya,having a very high risk of coastal erosion.In addition,Monte Carlo simulation was used to check the applicability of the CERA method,and it was found that the rate of shoreline change,population density,and number of storms significantly contributed to coastal erosion,but only the short-term effects of sea level rise were considered.The effects of sea level rise and sediment grain size were primarily analyzed as influencing factors.The effects of sea level rise continue to strengthen,with coastal retreat expected to be greater than 2 m by the mid-21st century.Moreover,Hainan Island is primarily composed of the fine and medium sand types,which have little resistance to coastal erosion.Currently,the impact of sediment grain size is rarely considered in coastal erosion risk assessment studies.However,it can be incorporated into the indicator system in the future,and the spatial variation of indicators can be fully considered to strengthen the refinement study.展开更多
基金supported by the Technological Project of Science and Technology Department of Henan Province in China,No.122102310205the National Natural Science Foundation of China,No.30771140,31070952,U1204311
文摘Prenatal alcohol exposure, especially during early pregnancy, can lead to fetal alcohol syndrome. The pharmacological and toxicological mechanisms of ethanol are related to the effects of ceramide In this study, we established an alcohol exposure model in wild-type mice and in knockout mice for the key enzyme involved in ceramide metabolism, sphingomyelin synthase 2. This model received daily intragastric administration of 25% ethanol, and pups were used at postnatal days 0, 7, 14, 30 for experiments. Serology and immunofluorescence staining found that ethanol exposure dose-dependently reduced blood sphingomyelin levels in two genotypes of pups, and increased neural cell proliferation and the number of new neurons in the hippocampal dentate gyrus. Western blot analysis showed that the relative expression level of protein kinase C e increased in two genotypes of pups after ethanol exposure. Compared with witd-type pups, the expression level of the important activator protein of the ceramide/ceramide-l-phosphate pathway, protein kinase C a, was reduced in the hippocampus of sphingomyelin synthase 2 knockouts. Our findings illustrate that ceramide is involved in alcohol-induced neural proliferation in the hippocampal dentate gyrus of pups after prenatal ethanol exposure, and the mechanism may be associated with increased ex- pression of protein kinase C a activating the ceramide/ceramide-l-phosphate pathway.
文摘近些年,随着教育研究领域的国际交流与合作日益频繁而密切,美国教育研究协会（The American Educational Research Association,简称AERA）逐步进入了中国教育学者的视野,其一年一度的大会不仅吸引着大批的中国学者积极通过各种方式前往参会,在中国国内经常也会借势刮起一阵AERA旋风,媒体报道、专题介绍、学术探讨……不一而足。
文摘Audiological use of the 40 Hz-ASSR (auditory steady state responses) could be valuable for objectivelyestimating the frequency-specific threshold in adults undergoing an expertise examination for medicolegal and/or compensation purposes. The present prospective study was set up to clarify the relationship between the thresholds obtained by cortical evoked response audiometry (CERA) and by 40 HzASSR, in the same ears, within a large homogeneous sample of 164 subjects (328 ears) with NIHL andwell documented exposure to noise. All these subjects claimed financial compensation for occupationalNIHL, and there was a suspicion of exaggeration of the reported NIHLs. ASSR thresholds show a goodcorrelation with the CERA thresholds. However, a systematic shift is noticed, ASSR thresholds being onaverage (1e2 e 3 kHz) 4.38 dB lower (i.e. showing less hearing loss) than CERA thresholds. Moreover, thebinaural multiple ASSR technique allows a considerable time gain when compared to the CERA.
文摘Carnuba wax consists chiefly of myricyl cerotate (M<sub>W</sub> 817.4) and small quantities of free cerotic acid (C<sub>26</sub>H<sub>52</sub>O<sub>2</sub>, Mw 396.7) and myricyl alcohol (C<sub>30</sub>H<sub>62</sub>O, mp 90°C). Of the two common extraction solvents, ethyl ether or petroleum ether, Lewkowitsch prefers the former. Concerning separation of phases, he advocates addition of small amounts of alcohol or caustic, and he also states that formation of a flocculant layer between the aqueous layer and the solvent does not interfere with the correct estimation of the unsaponifiable matter. These statements were not corroborated in the hands of this chemist. The “Unsaponifiable Matter” in oils or and fats, which consist mainly of hydrocarbons, sterols and aliphatic alcohols of high molecular mass that are not saponifiable by alkali hydroxides but are soluble in the ordinary fat solvents, and to products of saponification that are soluble in such solvents. Carnuba wax, a rather expensive wax, may be adulterated with less expensive paraffin by dishonest merchants. ASTM has a method for determining paraffinic material in carnuba wax. It uses heptanes at its boiling point to dissolve the wax, apply it to a silica gel column, and elute only the nonpolar (i.e. alkane) material. The method has the disadvantage of using a large volume of haptane, nor is it called for by either US Pharmacopeia/National Formulary (USP/NF) or Food Chemicals Codex (FCC). The test for unsaponifiable matter on pure carnuba wax will yield a result of 50.0% - 55.0%, while a higher result will betray the presence of paraffin adulterants.
文摘Optimization Algorithm was developed for the simula ti on of ceramic grain growth at atomistic scale. Based on the coordination informa tion of different atoms, a structure of trident tree was applied to save large q uantities data, so as to solve the problems of large data information and long r unning time. For every atom a binary tree was firstly formed according to the X coordination of atom. If the values of X coordination were the same, the middle sub-tree of first layer formed then a binary tree according to the Y coordinati on of atom. If the values of Y coordination were also the same, the middle sub- tree of second layer formed then a binary tree according to the Z coordination o f atom. In this way the speed of whole program is enhanced obviously. In order t o reduce memory, in this structure only need to store the exterior atoms’ infor mation, an integer is used to store the interior atoms’ information. If other a toms take up an atom’s all adjacent positions, this atom will be deleted in the data structure, for all the adjacent positions’ atoms, the integer’s relative bit will be set 1 to denote that there is an atom in this position but not be s tored in the trident tree. When an outside atom is deleted, for all the bits tha t are set 1,an atom will be added to the trident tree as an outside atom for the relative positions. And for this new added atom, the integer’s relative bi t of all the adjacent position’s atoms should be set 0 to denote that there is no interior atom in this position. In this way, if there are n 3 atoms, onl y need to store 6n 2 quantity’s atoms’ information. Large quantity of mem ory space can then be saved.
文摘Abstract In recent years, our research group has developed and studied new rare-earth doped materials for the promising technology of solid-state laser cooling, which is based on anti-stokes fluorescence. To the best of our knowledge, our group is the only one in Canada leading the research into the properties of nanoparticles, glasses and glass-ceramics for optical refrigeration appli- cations. In the present work, optical properties of 50GeO2- 30PbF2-18PbO-2YbF3 glass-ceramics for laser cooling are presented and discussed as a function of crystallization temperature. Spectroscopic results show that samples have near infrared photoluminescence emission due to the 2F5/2 - 2F7/2 Yb3＋ transition, centered at -1016 nm with an excitation wavelength of 920 nm or 1011 nm, and the highest photoluminescence emission efficiency occurs for heat-treatment for 5 h at 350℃. The internal photolumi- nescence quantum yield varies between 99% and 80%, depending on the temperature of heat-treatment, being the most efficient under 1011 nm excitation. The 2F5/2 lifetime increases from 1.472 to 1.970 ms for heat treatments at 330℃ to 350℃, respectively, due to energy trapping and the low phonon energy of the nanocrystals. The sample temperature dependence was measured with a fiber Bragg grating sensor, as a function of input pump laser wavelength and processing temperature. These measure- ments show that the heating process approaches near zero for an excitation wavelength between 1020 and 1030 nm, which is an indication that phonons are removed effectivelly from the glass-ceramic materials, and they can be used for optical laser cooling applications. On theother hand, the temperature increase as a function of input laser power into samples remains constant between 920 and 980 nm wavelength excitation, a temperature variation of 36 K/W （temperature of 58℃/W） was attained under excitation at 950 nm, showing a possible use for biomedical applications to be explored.
基金The National Natural Science Foundation of China under contract No.42176167the Innovation Fund of Guangdong Ocean University under contract No.Q18307the Postgraduate Education Innovation Project of Guangdong Ocean University under contract No.202252.
文摘Coastal erosion on islands is increasing due to sea level rise,frequent extreme events,and anthropogenic activities.However,studies on the multifactorial coastal erosion risk and the vulnerability of islands are limited.In this study,the Coastal Erosion Risk Assessment(CERA)method was applied for the first time to the study area in China to assess the erosion risk on the coast of Hainan Island;to explore the effects of coastal ocean dynamics,sediment movement characteristics,and anthropogenic construction;and to discuss the suitability of the method and countermeasures for coastal protection.The results show that the coast of Hainan Island shows high sensitivity,high value,low exposure,and moderate erosion.The whole island showed high vulnerability but low erosion risk,with the eastern region being more affected by erosion,particularly the eastern side of Wulong Port and Yalin Bay in Wenchang,and the shore section of Yalong Bay in Sanya,having a very high risk of coastal erosion.In addition,Monte Carlo simulation was used to check the applicability of the CERA method,and it was found that the rate of shoreline change,population density,and number of storms significantly contributed to coastal erosion,but only the short-term effects of sea level rise were considered.The effects of sea level rise and sediment grain size were primarily analyzed as influencing factors.The effects of sea level rise continue to strengthen,with coastal retreat expected to be greater than 2 m by the mid-21st century.Moreover,Hainan Island is primarily composed of the fine and medium sand types,which have little resistance to coastal erosion.Currently,the impact of sediment grain size is rarely considered in coastal erosion risk assessment studies.However,it can be incorporated into the indicator system in the future,and the spatial variation of indicators can be fully considered to strengthen the refinement study.
