Sleep disturbances are among the most prevalent neuropsychiatric symptoms in individuals who have recovered from severe acute respiratory syndrome coronavirus 2 infections.Previous studies have demonstrated abnormal b...Sleep disturbances are among the most prevalent neuropsychiatric symptoms in individuals who have recovered from severe acute respiratory syndrome coronavirus 2 infections.Previous studies have demonstrated abnormal brain structures in patients with sleep disturbances who have recovered from coronavirus disease 2019(COVID-19).However,neuroimaging studies on sleep disturbances caused by COVID-19 are scarce,and existing studies have primarily focused on the long-term effects of the virus,with minimal acute phase data.As a result,little is known about the pathophysiology of sleep disturbances in the acute phase of COVID-19.To address this issue,we designed a longitudinal study to investigate whether alterations in brain structure occur during the acute phase of infection,and verified the results using 3-month follow-up data.A total of 26 COVID-19 patients with sleep disturbances(aged 51.5±13.57 years,8 women and 18 men),27 COVID-19 patients without sleep disturbances(aged 47.33±15.98 years,9 women and 18 men),and 31 age-and gender-matched healthy controls(aged 49.19±17.51 years,9 women and 22 men)were included in this study.Eleven COVID-19 patients with sleep disturbances were included in a longitudinal analysis.We found that COVID-19 patients with sleep disturbances exhibited brain structural changes in almost all brain lobes.The cortical thicknesses of the left pars opercularis and left precuneus were significantly negatively correlated with Pittsburgh Sleep Quality Index scores.Additionally,we observed changes in the volume of the hippocampus and its subfield regions in COVID-19 patients compared with the healthy controls.The 3-month follow-up data revealed indices of altered cerebral structure(cortical thickness,cortical grey matter volume,and cortical surface area)in the frontal-parietal cortex compared with the baseline in COVID-19 patients with sleep disturbances.Our findings indicate that the sleep disturbances patients had altered morphology in the cortical and hippocampal structures during the acute phase of infection and persistent changes in cortical regions at 3 months post-infection.These data improve our understanding of the pathophysiology of sleep disturbances caused by COVID-19.展开更多
The main objective of the study was to investigate the characteristics of dissolved organic matter （DOM） in leachate with different landfill ages through the chemical, spectroscopic, and elemental analysis. Humic ac...The main objective of the study was to investigate the characteristics of dissolved organic matter （DOM） in leachate with different landfill ages through the chemical, spectroscopic, and elemental analysis. Humic acid （HA）, fulvic acid （FA）, and hydrophilic （HyI） fractions were isolated and purified by the XAD-8 resin combined with the cation exchange resin method. The analytical results of fluorescence excitation-emission matrix spectroscopy （EEMs） revealed that the fluorescence peaks were protein-like fluorescence for young landfill leachate, while the fluorescence peaks for medium and old landfill leachate were humic-like and fulvic-like fluorescence, respectively. Elemental analysis showed that carbon, hydrogen, and nitrogen content decreased with landfill age, while the oxygen content increased. Moreover, the nitrogen content in these isolated fractions followed： HA 〉 HyI 〉 FA. The results of elemental analysis, FT-IR, and fluorescence EEMs also confirmed that aromatic carbons and portions of aliphatic functional groups were more abundant in leachate samples with increasing landfill age.展开更多
In order to better understand the compositional and structural complexity of dissolved organic matter(DOM) macromolecules and provide mechanistic information on the binding of hydrophobic organic contaminants(HOCs) to...In order to better understand the compositional and structural complexity of dissolved organic matter(DOM) macromolecules and provide mechanistic information on the binding of hydrophobic organic contaminants(HOCs) to DOM, we fractionated large amounts of lake water into three hydrophobic DOM-fractions. The variation of the partitioning coef?cients(K_(DOC)) of pyrene at different p H levels was examined by ?orescence quenching titration. Results show that, relative to the more polar acidic DOM-fractions, the hydrophobic neutral fraction exhibits a higher sorption ability to pyrene. Generally, the sorption of pyrene to the three hydrophobic fractions is strongly pH-dependent. The K_(DOC) values of pyrene generally increase with decreasing p H levels, which is especially obvious in the sorption of pyrene to the fulvic acid fractions, suggesting that the binding is controlled by hydrophobic interactions. The mechanisms underlying the binding of pyrene to the hydrophobic fractions were also discussed. Our data are bene?cial to further understanding the binding of HOCs to DOM and how it has been affected,which may result in more accurate predictions of K_(DOC).展开更多
The performance of a disc tube (DT) methodology, originally designed for reverse osmosis (RO) in desalination, and applied here for ultrafiltration (UF) and nanofiltration (NF) of dissolved organic matter (DOM) in a s...The performance of a disc tube (DT) methodology, originally designed for reverse osmosis (RO) in desalination, and applied here for ultrafiltration (UF) and nanofiltration (NF) of dissolved organic matter (DOM) in a set of fresh (0 ppt), brackish (10 ppt) and saline (30 ppt) waters at low (1 - 2 mg/L), medium (5 - 6 mg/L) and high (10 - 12 mg/L) dissolved organic carbon (DOC) content is presented. The DT module allows for time efficient processing of large volumes of sample and can be operated with RO, NF and UF membranes. We examined the performance of a NF membrane with nominal molecular weight cut-off (MWCO) of 500 Da and UF membranes with MWCO of 1 kDa and 10 kDa. Throughout the experiments we monitored DOM in terms of DOC, UV-absorption coefficient ratios (E2/E3) and the specific UV-absorbance at 254 nm (SUVA254). Detailed protocols for operating the disc tube modules are proposed. The membranes can be efficiently cleaned to provide low carbon blanks ( mg/L). Calibration confirmed separation of high and low molecular weight standards into the retentate and permeate fractions, respectively. DOC mass balance of fractionated DOM samples showed good recoveries (123% ± 32% at 500 Da, 95% ± 12% at 1 kDa and 99% ± 11% at 10 kDa) (n = 9). The actual retention rates for 500 Da and 1 kDA were close to those reported by the manufacturer (~200 Da and ~3 kDa, respectively). However, the manufacturer’s rated 10 kDa membrane actually retained only DOM > 35 kDa. Salt addition (up to 30 ppt) caused a significant reduction in the amount of high molecular weight (HMW) compounds isolated in the 1 and 10 kDa retentates, due to coiling of macromolecules with increasing ionic strength. These findings underline the importance of stringent operating protocols and the salinity dependence of HMW retention.展开更多
White matter,a densely packed collection of myelinated axons,plays an essential part in neural networks.With high spatial resolution and deep penetration,multi-photon microscopy(MPM)is promising for white matter imagi...White matter,a densely packed collection of myelinated axons,plays an essential part in neural networks.With high spatial resolution and deep penetration,multi-photon microscopy(MPM)is promising for white matter imaging in animal models in vivo.The third harmonic generation(THG)signal can be generated from white matter,but the bottom part of the white matter layer generates weak THG due to its high scattering.Here,we demonstrate an in vivo labeling and imaging technology,capable of visualizing the white matter layer in the mouse brain,combining°uorescence labeling with MitoTracker Red and three-photon°uorescence(3PF)microscopy excited at the 1700 nm window.3PF signals are several times higher than THG signals,resulting in deeper imaging of the white matter layer with the former.Our results indicate that 3PF microscopy is a promising technology for white matter imaging in the deep brain in vivo.展开更多
基金supported by grants from Major Project of Science and Technology of Guangxi Zhuang Autonomous Region,No.Guike-AA22096018(to JY)Guangxi Key Research and Development Program,No.AB22080053(to DD)+6 种基金Major Project of Science and Technology of Guangxi Zhuang Autonomous Region,No.Guike-AA23023004(to MZ)the National Natural Science Foundation of China,Nos.82260021(to MZ),82060315(to DD)the Natural Science Foundation of Guangxi Zhuang Autonomous Region,No.2021GXNSFBA220007(to GD)Clinical Research Center For Medical Imaging in Hunan Province,No.2020SK4001(to JL)Key Emergency Project of Pneumonia Epidemic of Novel Coronavirus Infection in Hunan Province,No.2020SK3006(to JL)Science and Technology Innovation Program of Hunan Province,No.2021RC4016(to JL)Key Project of the Natural Science Foundation of Hunan Province,No.2024JJ3041(to JL).
文摘Sleep disturbances are among the most prevalent neuropsychiatric symptoms in individuals who have recovered from severe acute respiratory syndrome coronavirus 2 infections.Previous studies have demonstrated abnormal brain structures in patients with sleep disturbances who have recovered from coronavirus disease 2019(COVID-19).However,neuroimaging studies on sleep disturbances caused by COVID-19 are scarce,and existing studies have primarily focused on the long-term effects of the virus,with minimal acute phase data.As a result,little is known about the pathophysiology of sleep disturbances in the acute phase of COVID-19.To address this issue,we designed a longitudinal study to investigate whether alterations in brain structure occur during the acute phase of infection,and verified the results using 3-month follow-up data.A total of 26 COVID-19 patients with sleep disturbances(aged 51.5±13.57 years,8 women and 18 men),27 COVID-19 patients without sleep disturbances(aged 47.33±15.98 years,9 women and 18 men),and 31 age-and gender-matched healthy controls(aged 49.19±17.51 years,9 women and 22 men)were included in this study.Eleven COVID-19 patients with sleep disturbances were included in a longitudinal analysis.We found that COVID-19 patients with sleep disturbances exhibited brain structural changes in almost all brain lobes.The cortical thicknesses of the left pars opercularis and left precuneus were significantly negatively correlated with Pittsburgh Sleep Quality Index scores.Additionally,we observed changes in the volume of the hippocampus and its subfield regions in COVID-19 patients compared with the healthy controls.The 3-month follow-up data revealed indices of altered cerebral structure(cortical thickness,cortical grey matter volume,and cortical surface area)in the frontal-parietal cortex compared with the baseline in COVID-19 patients with sleep disturbances.Our findings indicate that the sleep disturbances patients had altered morphology in the cortical and hippocampal structures during the acute phase of infection and persistent changes in cortical regions at 3 months post-infection.These data improve our understanding of the pathophysiology of sleep disturbances caused by COVID-19.
文摘The main objective of the study was to investigate the characteristics of dissolved organic matter （DOM） in leachate with different landfill ages through the chemical, spectroscopic, and elemental analysis. Humic acid （HA）, fulvic acid （FA）, and hydrophilic （HyI） fractions were isolated and purified by the XAD-8 resin combined with the cation exchange resin method. The analytical results of fluorescence excitation-emission matrix spectroscopy （EEMs） revealed that the fluorescence peaks were protein-like fluorescence for young landfill leachate, while the fluorescence peaks for medium and old landfill leachate were humic-like and fulvic-like fluorescence, respectively. Elemental analysis showed that carbon, hydrogen, and nitrogen content decreased with landfill age, while the oxygen content increased. Moreover, the nitrogen content in these isolated fractions followed： HA 〉 HyI 〉 FA. The results of elemental analysis, FT-IR, and fluorescence EEMs also confirmed that aromatic carbons and portions of aliphatic functional groups were more abundant in leachate samples with increasing landfill age.
基金supported by the National Natural Science Foundation of China (No. 41173128)
文摘In order to better understand the compositional and structural complexity of dissolved organic matter(DOM) macromolecules and provide mechanistic information on the binding of hydrophobic organic contaminants(HOCs) to DOM, we fractionated large amounts of lake water into three hydrophobic DOM-fractions. The variation of the partitioning coef?cients(K_(DOC)) of pyrene at different p H levels was examined by ?orescence quenching titration. Results show that, relative to the more polar acidic DOM-fractions, the hydrophobic neutral fraction exhibits a higher sorption ability to pyrene. Generally, the sorption of pyrene to the three hydrophobic fractions is strongly pH-dependent. The K_(DOC) values of pyrene generally increase with decreasing p H levels, which is especially obvious in the sorption of pyrene to the fulvic acid fractions, suggesting that the binding is controlled by hydrophobic interactions. The mechanisms underlying the binding of pyrene to the hydrophobic fractions were also discussed. Our data are bene?cial to further understanding the binding of HOCs to DOM and how it has been affected,which may result in more accurate predictions of K_(DOC).
文摘The performance of a disc tube (DT) methodology, originally designed for reverse osmosis (RO) in desalination, and applied here for ultrafiltration (UF) and nanofiltration (NF) of dissolved organic matter (DOM) in a set of fresh (0 ppt), brackish (10 ppt) and saline (30 ppt) waters at low (1 - 2 mg/L), medium (5 - 6 mg/L) and high (10 - 12 mg/L) dissolved organic carbon (DOC) content is presented. The DT module allows for time efficient processing of large volumes of sample and can be operated with RO, NF and UF membranes. We examined the performance of a NF membrane with nominal molecular weight cut-off (MWCO) of 500 Da and UF membranes with MWCO of 1 kDa and 10 kDa. Throughout the experiments we monitored DOM in terms of DOC, UV-absorption coefficient ratios (E2/E3) and the specific UV-absorbance at 254 nm (SUVA254). Detailed protocols for operating the disc tube modules are proposed. The membranes can be efficiently cleaned to provide low carbon blanks ( mg/L). Calibration confirmed separation of high and low molecular weight standards into the retentate and permeate fractions, respectively. DOC mass balance of fractionated DOM samples showed good recoveries (123% ± 32% at 500 Da, 95% ± 12% at 1 kDa and 99% ± 11% at 10 kDa) (n = 9). The actual retention rates for 500 Da and 1 kDA were close to those reported by the manufacturer (~200 Da and ~3 kDa, respectively). However, the manufacturer’s rated 10 kDa membrane actually retained only DOM > 35 kDa. Salt addition (up to 30 ppt) caused a significant reduction in the amount of high molecular weight (HMW) compounds isolated in the 1 and 10 kDa retentates, due to coiling of macromolecules with increasing ionic strength. These findings underline the importance of stringent operating protocols and the salinity dependence of HMW retention.
基金funded by the National Natural Science Foundation of China(62075135,61975126)Shenzhen Key Laboratory of Photonics and Biophotonics(ZDSYS20210623092006020).
文摘White matter,a densely packed collection of myelinated axons,plays an essential part in neural networks.With high spatial resolution and deep penetration,multi-photon microscopy(MPM)is promising for white matter imaging in animal models in vivo.The third harmonic generation(THG)signal can be generated from white matter,but the bottom part of the white matter layer generates weak THG due to its high scattering.Here,we demonstrate an in vivo labeling and imaging technology,capable of visualizing the white matter layer in the mouse brain,combining°uorescence labeling with MitoTracker Red and three-photon°uorescence(3PF)microscopy excited at the 1700 nm window.3PF signals are several times higher than THG signals,resulting in deeper imaging of the white matter layer with the former.Our results indicate that 3PF microscopy is a promising technology for white matter imaging in the deep brain in vivo.
