Neuroscientists have recognized the importance of astrocytes in regulating neurological function and their influence on the release of glial transmitters.Few studies,however,have focused on the effects of general anes...Neuroscientists have recognized the importance of astrocytes in regulating neurological function and their influence on the release of glial transmitters.Few studies,however,have focused on the effects of general anesthetic agents on neuroglia or astrocytes.Astrocytes can also be an important target of general anesthetic agents as they exert not only sedative,analgesic,and amnesic effects but also mediate general anesthetic-induced neurotoxicity and postoperative cognitive dysfunction.Here,we analyzed recent advances in understanding the mechanism of general anesthetic agents on astrocytes,and found that exposure to general anesthetic agents will destroy the morphology and proliferation of astrocytes,in addition to acting on the receptors on their surface,which not only affect Ca^(2+)signaling,inhibit the release of brain-derived neurotrophic factor and lactate from astrocytes,but are even involved in the regulation of the pro-and anti-inflammatory processes of astrocytes.These would obviously affect the communication between astrocytes as well as between astrocytes and neighboring neurons,other neuroglia,and vascular cells.In this review,we summarize how general anesthetic agents act on neurons via astrocytes,and explore potential mechanisms of action of general anesthetic agents on the nervous system.We hope that this review will provide a new direction for mitigating the neurotoxicity of general anesthetic agents.展开更多
Objectives: Concerns regarding the real efficacy of transcatheter patent foramen ovale (PFO) closure versus medical therapy in patients with cryptogenic stroke remained unresolved. We performed a meta-analysis using t...Objectives: Concerns regarding the real efficacy of transcatheter patent foramen ovale (PFO) closure versus medical therapy in patients with cryptogenic stroke remained unresolved. We performed a meta-analysis using the randomized controlled trials on the efficacy and safety of transcatheter PFO closure in patients with cryptogenic stroke. Methods: Web of Science, EMBASE, PubMed, and the Cochrane Library were searched for relevant randomized controlled trials (RCTs). The primary outcome was recurrent stroke and transient-ischemic attack (TIA). Original data, hazard ratio (HR) with 95% confidence interval (95% CI) were abstracted to calculate a pooled effect size. Results: Our meta-analysis showed benefit with device closure when compared with medical therapy with an HR of 0.54 (95% CI: 0.39 - 0.74, P = 0.108) in the intention-to-treat cohort, 0.44 (95% CI: 0.24 - 0.82, P = 0.103) in the per-protocol populations, and 0.43 (95% CI: 0.31 - 0.60, P = 0.019) in the as-treated populations. There was a significantly higher incidence of new-onset atrial fibrillation in PFO closure patients (OR = 4.53, 95% CI: 2.58 - 7.97, P = 0.094). PFO Patients with an atrial septal aneurysm benefit from device closure (OR = 0.39, 95% CI: 0.22 - 0.69, P = 0.053). Patients with a substantial PFO shunt benefit the greatest with device closure with a pooled OR of 0.27 (95% CI: 0.14 - 0.56, P = 0.525). Conclusions: The meta-analysis concluded that PFO closure was associated with significantly lower risk of recurrent stroke in PFO patients with cryptogenic stroke than with medical therapy alone. The benefit of PFO closure was greater in patients with a substantial shunt and atrial septal aneurysm. PFO closure was associated with higher rates of new-onset atrial fibrillation.展开更多
The present study aims to estimate the in vivo anisotropic conductivities of the White Matter (WM) tissues by means of Magnetic Resonance Electrical Impedance Tomography (MREIT) technique. The realistic anisotropic vo...The present study aims to estimate the in vivo anisotropic conductivities of the White Matter (WM) tissues by means of Magnetic Resonance Electrical Impedance Tomography (MREIT) technique. The realistic anisotropic volume conductor model with different conductivity properties (scalp, skull, CSF, gray matter and WM) is constructed based on the Diffusion Tensor Magnetic Resonance Imaging (DT- MRI) from a healthy human subject. The Radius Basic Function (RBF)-MREIT algorithm of using only one magnetic flux density component was applied to evaluate the eigenvalues of the anisotropic WM with target values set according to the DT-MRI data based on the Wolter’s model, which is more physiologically reliable. The numerical simulations study performed on the five-layer realistic human head model showed that the conductivity reconstruction method had higher accuracy and better robustness against noise. The pilot research was used to judge the feasibility, meaningfulness and reliability of the MREIT applied on the electrical impedance tomography of the complicated human head tissues including anisotropic characteristics.展开更多
In this paper the recent Magnetic resonance electrical impedance imaging (MREIT) technique is used to image non-invasively the three-dimensional continuous conductivity distribution of the head tissues. With the feasi...In this paper the recent Magnetic resonance electrical impedance imaging (MREIT) technique is used to image non-invasively the three-dimensional continuous conductivity distribution of the head tissues. With the feasibility of the human head being rotated twice in the magnetic resonance imaging (MRI) system, a continuous conductivity reconstruction MREIT algorithm based on two components of the measured magnetic flux density is introduced. The reconstructed conductivity image could be obtained through solving iter- atively a non-linear matrix equation. According to the present algorithm of using two magnetic flux den- sity components, numerical simulations were per- formed on a concentric three-sphere and realistic human head model (consisting of the scalp, skull and brain) with the uniform and non-uniform isotropic target conductivity distributions. Based on the algorithm, the reconstruction of scalp and brain conductivity ratios could be figured out even under the condition that only one current is injected into the brain. The present results show that the three-dimensional continuous conductivity reconstruction method with two magnetic flux density components for the realistic head could get better results than the method with only one magnetic flux density component. Given the skull conductivity ratio, the relative errors of scalp and brain conductivity values were reduced to less than 1% with the uniform conductivity distribution and less than 6.5% with the non-uniform distribution for different noise levels. Furthermore, the algorithm also shows fast convergence and improved robustness against noise.展开更多
Facial expression recognition(FER)is still challenging due to the small interclass discrepancy in facial expression data.In view of the significance of facial crucial regions for FER,many existing studies utilize the ...Facial expression recognition(FER)is still challenging due to the small interclass discrepancy in facial expression data.In view of the significance of facial crucial regions for FER,many existing studies utilize the prior information from some annotated crucial points to improve the performance of FER.However,it is complicated and time-consuming to manually annotate facial crucial points,especially for vast wild expression images.Based on this,a local non-local joint network is proposed to adaptively enhance the facial crucial regions in feature learning of FER in this paper.In the proposed method,two parts are constructed based on facial local and non-local information,where an ensemble of multiple local networks is proposed to extract local features corresponding to multiple facial local regions and a non-local attention network is addressed to explore the significance of each local region.In particular,the attention weights obtained by the non-local network are fed into the local part to achieve interactive feedback between the facial global and local information.Interestingly,the non-local weights corresponding to local regions are gradually updated and higher weights are given to more crucial regions.Moreover,U-Net is employed to extract the integrated features of deep semantic information and low hierarchical detail information of expression images.Finally,experimental results illustrate that the proposed method achieves more competitive performance than several state-of-the-art methods on five benchmark datasets.展开更多
A small fraction of patients diagnosed with obesity or diabetes mellitus has an underlying monogenic cause.Here,we constructed a targeted gene panel consisting of 83 genes reported to be causative for monogenic obesit...A small fraction of patients diagnosed with obesity or diabetes mellitus has an underlying monogenic cause.Here,we constructed a targeted gene panel consisting of 83 genes reported to be causative for monogenic obesity or diabetes.We performed this panel in 481 patients to detect causative variants and compared these results with whole-exome sequencing(WES)data available for 146 of these patients.The coverage of targeted gene panel sequencing was significantly higher than that of WES.The diagnostic yield in patients sequenced by the panel was 32.9%with subsequent WES leading to three additional diagnoses with two novel genes.In total,178 variants in 83 genes were detected in 146 patients by targeted sequencing.Three of the 178 variants were missed by WES,although the WES-only approach had a similar diagnostic yield.For the 335 samples only receiving targeted sequencing,the diagnostic yield was 32.2%.In conclusion,taking into account the lower costs,shorter turnaround time,and higher quality of data,targeted sequencing is a more effective screening method for monogenic obesity and diabetes compared to WES.Therefore,this approach could be routinely established and used as a first-tier test in clinical practice for specific patients.展开更多
This study aimed to evaluate the spatial and temporal variations of molybdenum(Mo)in the downstream water body of a Mo mine during three hydrologic periods(wet,dry and medium seasons).The physical properties in Luhun ...This study aimed to evaluate the spatial and temporal variations of molybdenum(Mo)in the downstream water body of a Mo mine during three hydrologic periods(wet,dry and medium seasons).The physical properties in Luhun Reservoir reflected seasonal variations in different hydrological periods.The redox potential(ORP)and dissolved oxygen(DO)increased in the dry season.The concomitant decrease in temperature(T),conductivity(COND)and total dissolved solids(TDS)were lowest in the wet season.The p H value did not change significantly during the three hydrologic periods.The distribution of Mo in the dry season was high in upstream and low in downstream areas,which was significantly different from that of the wet and medium seasons.The total Mo concentration in wet(150.1μg/L)and medium season(148.2μg/L)was higher than that in the dry season,but the TDS(288.3 mg/L)and the percentage dissolved Mo(81.3%)in overlying water was lowest in the wet season.There was no significant relationship between the dissolved Mo and the total Mo with TDS.In the dry season,the mean total Mo concentration was 116.3μg/L,which was higher than the standard limit value(70μg/L)for drinking water(US EPA-United States Environmental Protection Agency recommended value 40μg/L).Non-point source pollution is the main characteristic of mining area pollution,which was closely related to rainfall.Thus,the Luhun Reservoir contains substantial Mo pollution,which was a significant concern given that it is used as a source of drinking and irrigation water.展开更多
Segment drying is a severe physiological disorder of citrus fruit,and vesicles become granulated or collapsed.Aside from the hypothesis that alteration of cell wall metabolism is the main factor of citrus granulation,...Segment drying is a severe physiological disorder of citrus fruit,and vesicles become granulated or collapsed.Aside from the hypothesis that alteration of cell wall metabolism is the main factor of citrus granulation,little is known about vesicle collapse.This study aimed to elucidate the changes in pectin metabolism during vesicle collapse in blood orange.Vesicle collapse was characterized by decreased nutrients and increased chelate-and sodium carbonate-soluble pectin and calcium content.The nanostructure of chelate-soluble pectin became complex and developed multi-branching upon collapse.The activity of pectin methylesterase increased,while that of polygalacturonase and pectate lyase decreased upon collapse.Genome-wide transcriptional analysis revealed an increasing pattern of genes encoding pectin methylesterase and other enzymes involved in pectin synthesis and demethylesterification upon collapse.Drying vesicles were characterized by increased abscisic acid content and relevant gene expression.In conclusion,we discovered alteration in pectin metabolism underlying citrus vesicle collapse,mainly promoting pectin demethylesterification,remodeling pectin structures,and further inhibiting pectin degradation,which was hypothesized to be a main factor for citrus collapse.This is the first study to disclose the potential intrinsic mechanism underlying vesicle collapse in orange fruit.展开更多
Background and Originality Content Reduction of esters to corresponding alcohols is a fundamental transformation in organic chemistry.111 Conventionally,this transformation is realized by employing hydride sourc...Background and Originality Content Reduction of esters to corresponding alcohols is a fundamental transformation in organic chemistry.111 Conventionally,this transformation is realized by employing hydride sources or hydrogenation mediated by transition metal catalysts.12,31 The major demerit of metal hydride reduction Is the handling of the intrinsically unsafe pyrophoric and moisture sensitive chemical agents,especially at large scale.Moreover,quenching the excessive reactive metal hydrides during workup and the disposal of the effluent generated may pose additional cumbersome environmental bur-den.pal For transition metal mediated hydrogenation,usually harsh conditions with elevated reaction temperature accompanying with high pressure are mandatory.展开更多
Cadmium(Cd)uptake by plants or benthic organisms largely depends on its bioavailability in sediments,so it is necessary to understand Cd bio availability for determining its ecological risks in riverine sediments.Pore...Cadmium(Cd)uptake by plants or benthic organisms largely depends on its bioavailability in sediments,so it is necessary to understand Cd bio availability for determining its ecological risks in riverine sediments.Pore water is easily disturbed during sample collection,indicating that there was a shortage of traditional methods for investigating Cd bio availability.Here,sediment cores were collected from rivers,after which sequential extraction and diffusive gradients in thin films(DGT)method were employed to determine Cd potential bio availability in the sediments and pore water.We found that Cd concentrations measured by DGT were lower than that in pore water profiles,and Cd distribution in various fractions changed remarkably.Pearson correlation analysis showed significant positive correlations between Cd concentrations measured by DGT and total Cd concentrations(r^2=0.76),exchangeable and weak acid soluble fraction(r^2=0.68),ferromanganese fraction(r^2=0.72)and bound organic matter or oxidizable fraction(r^2=0.54).However,the correlation was relatively low between Cd concentrations measured by DGT and that in pore water profiles(r^2=0.26).These results demonstrated that DGT method could provide more accurate information of Cd bio availability in sediment profiles than traditional methods.展开更多
The livestock breeding industries face overuse of antibiotics,which has been intensively studied in recent years.However,the occurrence and fate of antibiotics as well as their potential threats to the aquatic environ...The livestock breeding industries face overuse of antibiotics,which has been intensively studied in recent years.However,the occurrence and fate of antibiotics as well as their potential threats to the aquatic environments in alpine and arid regions remain unclear.This study investigated the relationship of the occurrence and concentrations of antibi-otics between the Kaidu River and Bosten Lake in a typical alpine basin in China.Hot spots with antibiotic pollution source were explored.The antibiotic concentrations in river water and suspended sediment(SPS)were 2.20-99.4 ng/L and 1.03-176 ng/g.The dominant antibi-otics were tetracyclines,sulphacetamide,and ofloxacin in river water and sulfonamides,clarithromycin,roxithromycin,and ofloxacin in SPS.The apparent differences in pollution sources and landscapes in different reaches led to the obvious spatial patterns of antibiotics in the Kaidu River.Higher partition coefficient of antibiotic between SPS and water phases for sulfonamides than tetracyclines was because that tetracyclines strongly responded to clay contents while sulfonamides significantly responded to organic carbon contents in SPS.There were significant differences in detected antibiotic categories between the river and the lake.Fluoroquinolones(especially ciprofloxacin and enrofloxacin)were detected in the lake while sulphacetamide was only detected in the river.Therefore,the surrounding husbandry and aquaculture around the Bosten Lake was an important antibiotic pollution source in addition to inputs from the Kaidu River.This research suggested that alpine lakes could be an important sink of antibiotics in alpine dry regions,and thus impose greater threats to the aquatic ecosystem.展开更多
基金supported by the National Natural Science Foundation of China,Nos.82171260,81641042,81471240the Natural Science Foundation of Zhejiang Province,Nos.LZ22H090002 and 2014C33170(all to ZH)。
文摘Neuroscientists have recognized the importance of astrocytes in regulating neurological function and their influence on the release of glial transmitters.Few studies,however,have focused on the effects of general anesthetic agents on neuroglia or astrocytes.Astrocytes can also be an important target of general anesthetic agents as they exert not only sedative,analgesic,and amnesic effects but also mediate general anesthetic-induced neurotoxicity and postoperative cognitive dysfunction.Here,we analyzed recent advances in understanding the mechanism of general anesthetic agents on astrocytes,and found that exposure to general anesthetic agents will destroy the morphology and proliferation of astrocytes,in addition to acting on the receptors on their surface,which not only affect Ca^(2+)signaling,inhibit the release of brain-derived neurotrophic factor and lactate from astrocytes,but are even involved in the regulation of the pro-and anti-inflammatory processes of astrocytes.These would obviously affect the communication between astrocytes as well as between astrocytes and neighboring neurons,other neuroglia,and vascular cells.In this review,we summarize how general anesthetic agents act on neurons via astrocytes,and explore potential mechanisms of action of general anesthetic agents on the nervous system.We hope that this review will provide a new direction for mitigating the neurotoxicity of general anesthetic agents.
文摘Objectives: Concerns regarding the real efficacy of transcatheter patent foramen ovale (PFO) closure versus medical therapy in patients with cryptogenic stroke remained unresolved. We performed a meta-analysis using the randomized controlled trials on the efficacy and safety of transcatheter PFO closure in patients with cryptogenic stroke. Methods: Web of Science, EMBASE, PubMed, and the Cochrane Library were searched for relevant randomized controlled trials (RCTs). The primary outcome was recurrent stroke and transient-ischemic attack (TIA). Original data, hazard ratio (HR) with 95% confidence interval (95% CI) were abstracted to calculate a pooled effect size. Results: Our meta-analysis showed benefit with device closure when compared with medical therapy with an HR of 0.54 (95% CI: 0.39 - 0.74, P = 0.108) in the intention-to-treat cohort, 0.44 (95% CI: 0.24 - 0.82, P = 0.103) in the per-protocol populations, and 0.43 (95% CI: 0.31 - 0.60, P = 0.019) in the as-treated populations. There was a significantly higher incidence of new-onset atrial fibrillation in PFO closure patients (OR = 4.53, 95% CI: 2.58 - 7.97, P = 0.094). PFO Patients with an atrial septal aneurysm benefit from device closure (OR = 0.39, 95% CI: 0.22 - 0.69, P = 0.053). Patients with a substantial PFO shunt benefit the greatest with device closure with a pooled OR of 0.27 (95% CI: 0.14 - 0.56, P = 0.525). Conclusions: The meta-analysis concluded that PFO closure was associated with significantly lower risk of recurrent stroke in PFO patients with cryptogenic stroke than with medical therapy alone. The benefit of PFO closure was greater in patients with a substantial shunt and atrial septal aneurysm. PFO closure was associated with higher rates of new-onset atrial fibrillation.
文摘The present study aims to estimate the in vivo anisotropic conductivities of the White Matter (WM) tissues by means of Magnetic Resonance Electrical Impedance Tomography (MREIT) technique. The realistic anisotropic volume conductor model with different conductivity properties (scalp, skull, CSF, gray matter and WM) is constructed based on the Diffusion Tensor Magnetic Resonance Imaging (DT- MRI) from a healthy human subject. The Radius Basic Function (RBF)-MREIT algorithm of using only one magnetic flux density component was applied to evaluate the eigenvalues of the anisotropic WM with target values set according to the DT-MRI data based on the Wolter’s model, which is more physiologically reliable. The numerical simulations study performed on the five-layer realistic human head model showed that the conductivity reconstruction method had higher accuracy and better robustness against noise. The pilot research was used to judge the feasibility, meaningfulness and reliability of the MREIT applied on the electrical impedance tomography of the complicated human head tissues including anisotropic characteristics.
文摘In this paper the recent Magnetic resonance electrical impedance imaging (MREIT) technique is used to image non-invasively the three-dimensional continuous conductivity distribution of the head tissues. With the feasibility of the human head being rotated twice in the magnetic resonance imaging (MRI) system, a continuous conductivity reconstruction MREIT algorithm based on two components of the measured magnetic flux density is introduced. The reconstructed conductivity image could be obtained through solving iter- atively a non-linear matrix equation. According to the present algorithm of using two magnetic flux den- sity components, numerical simulations were per- formed on a concentric three-sphere and realistic human head model (consisting of the scalp, skull and brain) with the uniform and non-uniform isotropic target conductivity distributions. Based on the algorithm, the reconstruction of scalp and brain conductivity ratios could be figured out even under the condition that only one current is injected into the brain. The present results show that the three-dimensional continuous conductivity reconstruction method with two magnetic flux density components for the realistic head could get better results than the method with only one magnetic flux density component. Given the skull conductivity ratio, the relative errors of scalp and brain conductivity values were reduced to less than 1% with the uniform conductivity distribution and less than 6.5% with the non-uniform distribution for different noise levels. Furthermore, the algorithm also shows fast convergence and improved robustness against noise.
文摘Facial expression recognition(FER)is still challenging due to the small interclass discrepancy in facial expression data.In view of the significance of facial crucial regions for FER,many existing studies utilize the prior information from some annotated crucial points to improve the performance of FER.However,it is complicated and time-consuming to manually annotate facial crucial points,especially for vast wild expression images.Based on this,a local non-local joint network is proposed to adaptively enhance the facial crucial regions in feature learning of FER in this paper.In the proposed method,two parts are constructed based on facial local and non-local information,where an ensemble of multiple local networks is proposed to extract local features corresponding to multiple facial local regions and a non-local attention network is addressed to explore the significance of each local region.In particular,the attention weights obtained by the non-local network are fed into the local part to achieve interactive feedback between the facial global and local information.Interestingly,the non-local weights corresponding to local regions are gradually updated and higher weights are given to more crucial regions.Moreover,U-Net is employed to extract the integrated features of deep semantic information and low hierarchical detail information of expression images.Finally,experimental results illustrate that the proposed method achieves more competitive performance than several state-of-the-art methods on five benchmark datasets.
基金supported by grants from Shanghai Outstanding Academic Leaders(20XD1433300)Medical-Engineering Cross Foundation of Shanghai Jiao Tong University(YG2021ZD20)+3 种基金Shuguang Project(21SG11),Innovative Research Team of High-level Local Universities in Shanghai(SHSMU-ZDCX20212700)Shanghai Research Center for Endocrine,Metabolic Diseases(2022ZZ01002)Shanghai Sixth People’s Hospital Grant(ynhg202204)Shanghai Municipal Key Clinical Specialty.
文摘A small fraction of patients diagnosed with obesity or diabetes mellitus has an underlying monogenic cause.Here,we constructed a targeted gene panel consisting of 83 genes reported to be causative for monogenic obesity or diabetes.We performed this panel in 481 patients to detect causative variants and compared these results with whole-exome sequencing(WES)data available for 146 of these patients.The coverage of targeted gene panel sequencing was significantly higher than that of WES.The diagnostic yield in patients sequenced by the panel was 32.9%with subsequent WES leading to three additional diagnoses with two novel genes.In total,178 variants in 83 genes were detected in 146 patients by targeted sequencing.Three of the 178 variants were missed by WES,although the WES-only approach had a similar diagnostic yield.For the 335 samples only receiving targeted sequencing,the diagnostic yield was 32.2%.In conclusion,taking into account the lower costs,shorter turnaround time,and higher quality of data,targeted sequencing is a more effective screening method for monogenic obesity and diabetes compared to WES.Therefore,this approach could be routinely established and used as a first-tier test in clinical practice for specific patients.
基金supported by the National Natural Science Foundation of China(Nos.41701546 and 41877368)the Youth Innovation Promotion Association CAS(No.2017059)+1 种基金the Key Scientific Research Project of Colleges and Universities of the Henan Education Department(No.17A570001)the North China University of Water Resources and Hydropower Research Project for highlevel talents。
文摘This study aimed to evaluate the spatial and temporal variations of molybdenum(Mo)in the downstream water body of a Mo mine during three hydrologic periods(wet,dry and medium seasons).The physical properties in Luhun Reservoir reflected seasonal variations in different hydrological periods.The redox potential(ORP)and dissolved oxygen(DO)increased in the dry season.The concomitant decrease in temperature(T),conductivity(COND)and total dissolved solids(TDS)were lowest in the wet season.The p H value did not change significantly during the three hydrologic periods.The distribution of Mo in the dry season was high in upstream and low in downstream areas,which was significantly different from that of the wet and medium seasons.The total Mo concentration in wet(150.1μg/L)and medium season(148.2μg/L)was higher than that in the dry season,but the TDS(288.3 mg/L)and the percentage dissolved Mo(81.3%)in overlying water was lowest in the wet season.There was no significant relationship between the dissolved Mo and the total Mo with TDS.In the dry season,the mean total Mo concentration was 116.3μg/L,which was higher than the standard limit value(70μg/L)for drinking water(US EPA-United States Environmental Protection Agency recommended value 40μg/L).Non-point source pollution is the main characteristic of mining area pollution,which was closely related to rainfall.Thus,the Luhun Reservoir contains substantial Mo pollution,which was a significant concern given that it is used as a source of drinking and irrigation water.
基金funded by the National Natural Science Foundation of China(No.32172262)the Fundamental Research Funds for the Central Universities(No.XDJK2021F008)Chongqing Graduate Student Research Innovation Project(No.CYS21118),China.
文摘Segment drying is a severe physiological disorder of citrus fruit,and vesicles become granulated or collapsed.Aside from the hypothesis that alteration of cell wall metabolism is the main factor of citrus granulation,little is known about vesicle collapse.This study aimed to elucidate the changes in pectin metabolism during vesicle collapse in blood orange.Vesicle collapse was characterized by decreased nutrients and increased chelate-and sodium carbonate-soluble pectin and calcium content.The nanostructure of chelate-soluble pectin became complex and developed multi-branching upon collapse.The activity of pectin methylesterase increased,while that of polygalacturonase and pectate lyase decreased upon collapse.Genome-wide transcriptional analysis revealed an increasing pattern of genes encoding pectin methylesterase and other enzymes involved in pectin synthesis and demethylesterification upon collapse.Drying vesicles were characterized by increased abscisic acid content and relevant gene expression.In conclusion,we discovered alteration in pectin metabolism underlying citrus vesicle collapse,mainly promoting pectin demethylesterification,remodeling pectin structures,and further inhibiting pectin degradation,which was hypothesized to be a main factor for citrus collapse.This is the first study to disclose the potential intrinsic mechanism underlying vesicle collapse in orange fruit.
基金We gratefully acknowledge financial support from the National Natural Science Foundation of China(Grant No.21372171)and PAPD.
文摘Background and Originality Content Reduction of esters to corresponding alcohols is a fundamental transformation in organic chemistry.111 Conventionally,this transformation is realized by employing hydride sources or hydrogenation mediated by transition metal catalysts.12,31 The major demerit of metal hydride reduction Is the handling of the intrinsically unsafe pyrophoric and moisture sensitive chemical agents,especially at large scale.Moreover,quenching the excessive reactive metal hydrides during workup and the disposal of the effluent generated may pose additional cumbersome environmental bur-den.pal For transition metal mediated hydrogenation,usually harsh conditions with elevated reaction temperature accompanying with high pressure are mandatory.
基金supported by the Youth Innovation Promotion Association CAS(Wenzhong Tang,2017059)the National Natural Science Foundation of China(No.41877368)
文摘Cadmium(Cd)uptake by plants or benthic organisms largely depends on its bioavailability in sediments,so it is necessary to understand Cd bio availability for determining its ecological risks in riverine sediments.Pore water is easily disturbed during sample collection,indicating that there was a shortage of traditional methods for investigating Cd bio availability.Here,sediment cores were collected from rivers,after which sequential extraction and diffusive gradients in thin films(DGT)method were employed to determine Cd potential bio availability in the sediments and pore water.We found that Cd concentrations measured by DGT were lower than that in pore water profiles,and Cd distribution in various fractions changed remarkably.Pearson correlation analysis showed significant positive correlations between Cd concentrations measured by DGT and total Cd concentrations(r^2=0.76),exchangeable and weak acid soluble fraction(r^2=0.68),ferromanganese fraction(r^2=0.72)and bound organic matter or oxidizable fraction(r^2=0.54).However,the correlation was relatively low between Cd concentrations measured by DGT and that in pore water profiles(r^2=0.26).These results demonstrated that DGT method could provide more accurate information of Cd bio availability in sediment profiles than traditional methods.
基金This work was supported by the National Key Research and Development Program of China(No.2017YFC0404501)the National Natural Science Foundation of China(No.51809177)+1 种基金China Postdoctoral Science Foundation(No.2018M630576)Special Fund for Basic Scientific Research of Central Public Research Institutes NHRI Youth fund(No.Y918017).
文摘The livestock breeding industries face overuse of antibiotics,which has been intensively studied in recent years.However,the occurrence and fate of antibiotics as well as their potential threats to the aquatic environments in alpine and arid regions remain unclear.This study investigated the relationship of the occurrence and concentrations of antibi-otics between the Kaidu River and Bosten Lake in a typical alpine basin in China.Hot spots with antibiotic pollution source were explored.The antibiotic concentrations in river water and suspended sediment(SPS)were 2.20-99.4 ng/L and 1.03-176 ng/g.The dominant antibi-otics were tetracyclines,sulphacetamide,and ofloxacin in river water and sulfonamides,clarithromycin,roxithromycin,and ofloxacin in SPS.The apparent differences in pollution sources and landscapes in different reaches led to the obvious spatial patterns of antibiotics in the Kaidu River.Higher partition coefficient of antibiotic between SPS and water phases for sulfonamides than tetracyclines was because that tetracyclines strongly responded to clay contents while sulfonamides significantly responded to organic carbon contents in SPS.There were significant differences in detected antibiotic categories between the river and the lake.Fluoroquinolones(especially ciprofloxacin and enrofloxacin)were detected in the lake while sulphacetamide was only detected in the river.Therefore,the surrounding husbandry and aquaculture around the Bosten Lake was an important antibiotic pollution source in addition to inputs from the Kaidu River.This research suggested that alpine lakes could be an important sink of antibiotics in alpine dry regions,and thus impose greater threats to the aquatic ecosystem.
