The occurrence of ultrafiltration(UF)membrane fouling frequently hampers the sustainable advancement of UF technology.Reactive self-cleaning UF membranes can effectively alleviate the problem of membrane fouling.Never...The occurrence of ultrafiltration(UF)membrane fouling frequently hampers the sustainable advancement of UF technology.Reactive self-cleaning UF membranes can effectively alleviate the problem of membrane fouling.Nevertheless,the self-cleaning process may accelerate membrane aging.Addressing these concerns,we present an innovative design concept for composite self-healing materials based on self-cleaning UF membranes.To begin,TiO_(2)nanoparticles were incorporated into the polymer molecular structure via molecular design,resulting in the synthesis of TiO_(2)/carboxyl-polyether sulfone(PES)hybrid materials.Subsequently,the nonsolvent-induced phase inversion technique was employed to prepare a novel of UF membrane.Lastly,a polyvinyl alcohol(PVA)hydrogel coating was applied to the hybrid UF membrane surface to create PVA@TiO_(2)/carboxyl-PES self-healing reactive UF membranes.By establishing a covalent bond,the TiO_(2)nanoparticles were effectively and uniformly dispersed within the UF membrane,leading to exceptional self-cleaning properties.Furthermore,the water-absorbing and swelling properties of PVA hydrogel,along with its capacity to form hydrogen bonds with water molecules,resulted in UF membranes with improved hydrophilicity and active self-healing abilities.The results demonstrated that the water contact angle of PVA@5%TiO_(2)/carboxyl-PES UF membrane was 43.1°.Following a 1-h exposure to simulated solar exposure,the water flux recovery ratio increased from 48.16%to 81.03%.Moreover,even after undergoing five cycles of 12-h simulated sunlight exposure,the UF membranes exhibited a consistent retention rate of over 97%,thus fully demonstrating their exceptional self-cleaning,antifouling,and selfhealing capabilities.We anticipate that the self-healing reactive UF membrane system will serve as a pioneering and comprehensive solution for the self-cleaning antifouling challenges encountered in UF membranes while also effectively mitigating the aging effects of reactive UF membranes.展开更多
Promotion of new blood vessel formation is a new strategy for treating ischemic stroke.Non-coding miRNAs have been recently considered potential therapeutic targets for ischemic stroke.miR-181b has been shown to promo...Promotion of new blood vessel formation is a new strategy for treating ischemic stroke.Non-coding miRNAs have been recently considered potential therapeutic targets for ischemic stroke.miR-181b has been shown to promote angiogenesis in hypoxia and traumatic brain injury model,while its effect on ischemic stroke remains elusive.In this study,we found that overexpression of miR-181b in brain microvascular endothelial cells subjected to oxygen-glucose deprivation in vitro restored cell prolife ration and enhanced angiogenesis.In rat models of focal cerebral ischemia,ove rexpression of miR-181b reduced infarction volume,promoted angiogenesis in ischemic penumbra,and improved neurological function.We further investigated the molecular mechanism by which miR-181b participates in angiogenesis after ischemic stroke and found that miR-181b directly bound to the 3’-UTR of phosphatase and tensin homolog(PTEN) mRNA to induce PTEN downregulation,leading to activation of the protein kinase B(Akt) pathway,upregulated expression of vascular endothelial growth facto rs,down-regulated expression of endostatin,and promoted angiogenesis.Taken togethe r,these results indicate that exogenous miR-181b exhibits neuroprotective effects on ischemic stro ke through activating the PTEN/Akt signal pathway and promoting angiogenesis.展开更多
Causal inference is a powerful modeling tool for explanatory analysis,which might enable current machine learning to become explainable.How to marry causal inference with machine learning to develop explainable artifi...Causal inference is a powerful modeling tool for explanatory analysis,which might enable current machine learning to become explainable.How to marry causal inference with machine learning to develop explainable artificial intelligence(XAI)algorithms is one of key steps toward to the artificial intelligence 2.0.With the aim of bringing knowledge of causal inference to scholars of machine learning and artificial intelligence,we invited researchers working on causal inference to write this survey from different aspects of causal inference.This survey includes the following sections:“Estimating average treatment effect:A brief review and beyond”from Dr.Kun Kuang,“Attribution problems in counterfactual inference”from Prof.Lian Li,“The Yule–Simpson paradox and the surrogate paradox”from Prof.Zhi Geng,“Causal potential theory”from Prof.Lei Xu,“Discovering causal information from observational data”from Prof.Kun Zhang,“Formal argumentation in causal reasoning and explanation”from Profs.Beishui Liao and Huaxin Huang,“Causal inference with complex experiments”from Prof.Peng Ding,“Instrumental variables and negative controls for observational studies”from Prof.Wang Miao,and“Causal inference with interference”from Dr.Zhichao Jiang.展开更多
This study aimed to assess the reliability of experienced Chinese orthodontists in evaluating treatment outcome and to determine the correlations between three diagnostic information sources. Sixty-nine experienced Ch...This study aimed to assess the reliability of experienced Chinese orthodontists in evaluating treatment outcome and to determine the correlations between three diagnostic information sources. Sixty-nine experienced Chinese orthodontic specialists each evaluated the outcome of orthodontic treatment of 108 Chinese patients. Three different information sources: study casts(SC), lateral cephalometric X-ray images(LX) and facial photographs(PH) were generated at the end of treatment for 108 patients selected randomly from six orthodontic treatment centers throughout China. Six different assessments of treatment outcome were made by each orthodontist using data from the three information sources separately and in combination. Each assessment included both ranking and grading for each patient. The rankings of each of the 69 judges for the 108 patients were correlated with the rankings of each of the other judges yielding 13 873 Spearman rs values, ranging from –0.08 to 10.85. Of these, 90% were greater than 0.4, showing moderate-to-high consistency among the 69 orthodontists. In the combined evaluations, study casts were the most significant predictive component(R250.86, P,0.000 1), while the inclusion of lateral cephalometric films and facial photographs also contributed to a more comprehensive assessment(R250.96, P,0.000 1). Grading scores for SC1LX and SC1PH were highly significantly correlated with those for SC1LX1PH(r(SC1LX)vs.(SC1LX1PH) 50.96, r(SC1PH)vs.(SC1LX1PH) 50.97), showing that either SC1LX or SC1PH is an excellent substitute for all three combined assessment.展开更多
There is a great interest in developing microelectronic devices based on nanostructured conducting polymers that can selectively electro-couple analytes at high sensitivity and low power.Nanostructured conducting poly...There is a great interest in developing microelectronic devices based on nanostructured conducting polymers that can selectively electro-couple analytes at high sensitivity and low power.Nanostructured conducting polymers have emerged as promising candidates for this technology due to their excellent stability with low redox potential,high conductivity,and selectivity endowed by chemical functionalization.However,it remains challenging to develop cost-effective and large-scale assembly approaches for functionalized conducting polymers in the practical fabrication of electronic devices.Here,we reported a straightforward waferscale assembly of nanostructured hexafluoroisopropanol functionalized poly(3,4-ethylenedioxythiophene)(PEDOT-HFIP)on smooth substrates.This approach is template-free,solution-processed,and adaptable to conductive and nonconductive substrates.By this approach,the nanostructured PEDOT-HFIPs could be easily integrated onto interdigitated electrodes with intimate ohmic contact.At the optimized space-to-volume ratio,we demonstrated a low-power,sensitive,and selective nerve agent sensing technology using this platform by detecting sarin vapor with a limit of detection(LOD)of 10 ppb and signal strength of 400 times the water interference at the same concentration,offering significant advantages over existing similar technologies.We envision that its easy scale-up,micro size,small power consumption,and combination of high sensitivity and selectivity make it attractive for various wearable platforms.展开更多
This paper proposes a single-ended fault detection scheme for long transmission lines using support vector machine(SVM)for multi-terminal direct current systems based on modular multilevel converter(MMC-MTDC).The sche...This paper proposes a single-ended fault detection scheme for long transmission lines using support vector machine(SVM)for multi-terminal direct current systems based on modular multilevel converter(MMC-MTDC).The scheme overcomes existing detection difficulties in the protection of long transmission lines resulting from high grounding resistance and attenuation,and also avoids the sophisticated process of threshold value selection.The high-frequency components in the measured voltage extracted by a wavelet transform and the amplitude of the zero-mode set of the positive-sequence voltage are the inputs to a trained SVM.The output of the SVM determines the fault type.A model of a four-terminal DC power grid with overhead transmission lines is built in PSCAD/EMTDC.Simulation results of EMTDC confirm that the proposed scheme achieves 100%accuracy in detecting short-circuit faults with high resistance on long transmission lines.The proposed scheme eliminates mal-operation of DC circuit breakers when faced with power order changes or AC-side faults.Its robustness and time delay are also assessed and shown to have no perceptible effect on the speed and accuracy of the detection scheme,thus ensuring its reliability and stability.展开更多
Conducting polymers offer attractive mixed ionic-electronic conductivity,tunable interfacial barrier with metal,tissue matchable softness,and versatile chemical functionalization,making them robust to bridge the gap b...Conducting polymers offer attractive mixed ionic-electronic conductivity,tunable interfacial barrier with metal,tissue matchable softness,and versatile chemical functionalization,making them robust to bridge the gap between brain tissue and electronic circuits.This review focuses on chemically revised conducting polymers,combined with their superior and controllable electrochemical performance,to fabricate long-term bioelectronic implants,addressing chronic immune responses,weak neuron attraction,and long-term electrocommunication instability challenges.Moreover,the promising progress of zwitterionic conducting polymers in bioelectronic implants(≥4 weeks stable implantation)is highlighted,followed by a comment on their current evolution toward selective neural coupling and reimplantable function.Finally,a critical forward look at the future of zwitterionic conducting polymers for in vivo bioelectronic devices is provided.展开更多
Background Previous studies havedemonstrated that excitatory repetitive transcranial magnetic stimulation(rTMS)can improve the cognitive function of patients with Alzheimer's disease(AD).Intermittent theta burst s...Background Previous studies havedemonstrated that excitatory repetitive transcranial magnetic stimulation(rTMS)can improve the cognitive function of patients with Alzheimer's disease(AD).Intermittent theta burst stimulation(iTBS)is a novel excitatory rTMS protocol for brain activity stimulation with the ability to induce long-term potentiation-like plasticity and represents a promising treatment for AD.However,the long-term effects of iTBS on cognitive decline and brain structure in patients with AD areunknown.Aims We aimed to explore whether repeating accelerated iTBS every three months could slow down the cognitive decline in patients with AD.Methods In this randomised,assessor-blinded,controlled trial,iTBS was administered to the left dorsolateral prefrontal cortex(DLPFC)of 42 patients with AD for 14days every 13weeks.Measurements included the Montreal Cognitive Assessment(MoCA),a comprehensive neuropsychological battery,and the grey matter volume(GMV)of the hippocampus.Patients were evaluated at baseline and after follow-up.The longitudinal pipeline of the Computational Anatomy Toolbox for SPM was used to detect significant treatment-related changes over time.Results The iTBS group maintained MoCA scores relative to the control group(t=3.26,p=0.013)and reduced hippocampal atrophy,which was significantly correlated with global degeneration scale changes.The baseline Mini-Mental State Examination(MMSE)score,apolipoprotein E genotype and Clinical Dementia Rating were indicative of MoCA scores at follow-up.Moreover,the GMV of the left(t=0.08,p=0.996)and right(t=0.19,p=0.977)hippocampus were maintained in the active group but significantly declined in the control group(left:t=4.13,p<0.001;right:t=5.31,p<0.001).GMV change in the left(r=0.35,p=0.023)and right(r=0.36,p=0.021)hippocampus across the intervention positively correlated with MoCA changes;left hippocampal GMV change was negatively correlated with global degeneration scale(r=-0.32,p=0.041)changes.Conclusions DLPFC-iTBS maybe a feasible and easy-to-implement non-pharmacological intervention to slow down the progressive decline of overall cognition and quality of life in patients with AD,providing a new AD treatment option.Trial registration number NCT04754152.展开更多
Transport behaviors of graphene oxide nanoparticles(GONPs) in saturated porous media were examined as a function of the presence and concentration of anionic surfactant(SDBS)and non-ionic surfactant(Triton X-100) unde...Transport behaviors of graphene oxide nanoparticles(GONPs) in saturated porous media were examined as a function of the presence and concentration of anionic surfactant(SDBS)and non-ionic surfactant(Triton X-100) under different ionic strength(IS). The results showed that the GONPs were retained obviously in the sand columns at both IS of 50 and200 mmol/L, and they were more mobile at lower IS. The presence and concentration of surfactants could enhance the GONP transport, particularly as observed at higher IS. It was interesting to see that the GONP transport was surfactant type dependent, and SDBS was more effective to facilitate GONP transport than Triton X-100 in our experimental conditions. The advection–dispersion–retention numerical modeling followed this trend and depicted the difference quantitatively. Derjaguin–Landau–Verwey–Overbeek(DLVO)interaction calculations also were performed to interpret these effects, indicating that secondary minimum deposition was critical in this study.展开更多
Aloin is a small-molecule drug well known for its protective actions in various models of damage.Traumatic brain injury(TBI)-induced cerebral edema from secondary damage caused by disruption of the blood-brain barrier...Aloin is a small-molecule drug well known for its protective actions in various models of damage.Traumatic brain injury(TBI)-induced cerebral edema from secondary damage caused by disruption of the blood-brain barrier(BBB) often leads to an adverse prognosis.Since the role of aloin in maintaining the integrity of the BBB after TBI remains unclear,we explored the protective effects of aloin on the BBB using in vivo and in vitro TBI models.Adult male C57 BL/6 mice underwent controlled cortical impact injury,and mouse brain capillary endothelial bEnd.3 cells underwent biaxial stretch injury,then both received aloin treatment.In the animal experiments,we found 20 mg/kg aloin to be the optimum concentration to decrease cerebral edema,decrease disruption of the BBB,and improve neurobehavioral performance after cortical impact injury.In the cellular studies,the optimum concentration of 40 μg/mL aloin reduced apoptosis and reversed the loss of tight junctions by reducing the reactive oxygen species levels and changes in mitochondrial membrane potential after stretch injury.The mechanisms may be that aloin downregulates the phosphorylation of p38 mitogen-activated protein kinase,the activation of p65 nuclear factor-kappa B,and the ratios of B cell lymphoma(Bcl)-2-associated X protein/Bcl-2 and cleaved caspase-3/caspase-3.We conclude that aloin exhibits these protective effects on the BBB after TBI through its anti-oxidative stress and anti-apoptotic properties in mouse brain capillary endothelial cells.Aloin may thus be a promising therapeutic drug for TBI.展开更多
pH-sensitive wettability of polystyrene-b-poly(4-vinylpyridine)(PS-b-P4VP) self assembled films, exhibiting superoleophobicity under water and hydrophilicity at low pH value, and oleophobicity under water and hydropho...pH-sensitive wettability of polystyrene-b-poly(4-vinylpyridine)(PS-b-P4VP) self assembled films, exhibiting superoleophobicity under water and hydrophilicity at low pH value, and oleophobicity under water and hydrophobicity at neutral condition, has been realized. The wettability properties resulted from the surface topological and chemical transition, which were confirmed by in situ AFM measurements under water at different pH. At low pH, P4VP chains, which were confined in the hexagonal-packed nanodomains, got protonated into a swollen state, while at high pH, P4VP chains were deprotonated into a collapsed state. The reversible protonation/deprotonation procedure on the molecular scale leads to surface topological and chemical transition, thereby pH-sensitive wettability.展开更多
The ionic conductivity and the mechanical strength are two key factors for the performance of poly(ethylene oxide)(PEO) based polyelectrolytes. However, crystallized PEO suppresses ion conductivity at low temperature ...The ionic conductivity and the mechanical strength are two key factors for the performance of poly(ethylene oxide)(PEO) based polyelectrolytes. However, crystallized PEO suppresses ion conductivity at low temperature and melted PEO has low mechanical strength at high temperature. Here, random binary brush copolymer composed of PEO-and polystyrene(PS)-based side chains is synthesized. PEO crystallinity is suppressed by the introduction of PS brushes. Doping with lithium trifluoromethanesulfonate(Li Tf) induces microphase separation. Due to a random arrangement of the brushes, the microphase segregation is incomplete even at high salt loading, which provides both high ionic conductivity and high mechanical strength at room temperature. These results provide opportunities for the design of polymeric electrolytes to be used at room temperature.展开更多
Background The search of heavy atoms is crucial to the de novo determination of protein structures.Typically,the difference Patterson map is calculated as a first step to solve substructure.However,the pseudo-peaks an...Background The search of heavy atoms is crucial to the de novo determination of protein structures.Typically,the difference Patterson map is calculated as a first step to solve substructure.However,the pseudo-peaks and noises inherent in such maps arising from the high symmetry and large size of protein structures accompanied with the data collection errors inevitably pose a challenge in accurate real space-based substructure determination.Purpose In order to mitigate such pseudo-peaks and noises and further improve signal-to-noise ratio(SNR)of the difference Patterson map,the noise and artifact suppression using resampling(NASR)method originally proposed in nuclear magnetic resonance is introduced into protein crystallography in this work to optimize the difference Patterson map.Methods The NASR method makes use of the statistical learning theory,which in this work repeatedly samples a fixed portion of diffraction data(sub-dataset)randomly followed by a statistical analysis of the multiple calculated difference Patterson maps to discard pseudo-peaks and noises.Its feasibility is based on the fact that the true vector peaks of the heavy atoms keep static in the multiple random sub-datasets,whereas the pseudo-peaks and noises fluctuate remarkably.And the key of this method lies in the design of a weighting function to distinguish true vector peaks from pseudo-peaks and noises,as well as a proper selection of the parameters associated with the function.Results The introduced NASR method is both numerically and experimentally demonstrated to be feasible in suppressing spurious peaks and non-correlative noises intrinsic to the difference Patterson maps.As a result,the SNR of the difference Patterson maps can be enhanced to some extent to facilitate real space-based substructure determination.Conclusion It is therefore anticipated that the proposed method may provide a meaningful insight into how to denoise the difference Patterson maps,which in turn assists in locating heavy atoms and further facilitates de novo protein structure determination.展开更多
Novel functional hyperbranched poly(aryl ether ketone)s(HPAEKs) bonded with nonlinear optical chromophores(meso-tetrakis(4-hydroxyphenyl) porphyrin, THPP and its metal derivatives) were synthesized and characterized b...Novel functional hyperbranched poly(aryl ether ketone)s(HPAEKs) bonded with nonlinear optical chromophores(meso-tetrakis(4-hydroxyphenyl) porphyrin, THPP and its metal derivatives) were synthesized and characterized by 1H-NMR and UV-Vis absorption spectra. The incorporation of chromophores into HPAEKs endowed HPAEKs novel NLO and OL properties. Indeed, dendritic architecture allowed for maximum dispersion of the chromophores, avoided aggregation, more optical limiting property was obtained. Simultaneously, they retained the excellent properties of the materials, particularly in thermal stability. Their optical properties were evaluated by nonlinear optical analyses and optical limiting. The results showed that these polymers possessed good optical limiting(OL) property and large nonlinear optical(NLO) susceptibilities(ca. 10 12esu). All polymers containing chromophores presented excellent thermal stability(DT5 > 524.17 °C).展开更多
Background Recent advances in serial femtosecond crystallography(SFX)using X-ray free electron lasers(XFELs)have facilitated accurate structure determination for biological macromolecules.However,given the many fluctu...Background Recent advances in serial femtosecond crystallography(SFX)using X-ray free electron lasers(XFELs)have facilitated accurate structure determination for biological macromolecules.However,given the many fluctuations inherent in SFX,the acquisition of SFX data of sufficiently high quality still remains challenging.Method Aimed at enhancing the accuracy of SFX data,this study proposes an iterative refinement method to optimally match pairs of the observed and predicted reflections on the detector plane.This method features a combination of detector geometry optimization and diffraction model refinement in an alternate manner,concomitant with a cycle-by-cycle peak selection procedure.Result To demonstrate whether this iterative method is convergent and feasible,both numerical simulations and experimental tests have been performed.The results reveal that this method can gradually improve overall quality of the integrated SFX data and therefore accelerate the convergence of Monte Carlo integration,while simultaneously suppressing correlations inherent in certain parameters and precluding outliers to some extent during the refinement.Conclusion We have demonstrated that our iterative refinement method is applicable to both simulated and experimental SFX data.It is expected that this method could provide meaningful insights into the refinement of SFX data and take the step forward toward more accurate Monte Carlo integration.展开更多
Background Finding methods to judge the quality of X-ray crystallographic information is an active research topic.The quality of electron density maps reconstructed by Fourier transform is always limited by the finite...Background Finding methods to judge the quality of X-ray crystallographic information is an active research topic.The quality of electron density maps reconstructed by Fourier transform is always limited by the finite resolution,the amplitude/phase error and the completeness of diffraction data.At present,the R value and effective resolution are common ways of evaluating the quality of electron density maps.Unfortunately,the current evaluation methods are only dependent on diffraction amplitude,without any phase information.Methods Advanced evaluation functions in real space are designed to estimate the electron density map quality.The electron density map definition evaluation function relies on the atomicity of the electron density distribution.We use the power spectrum electron density entropy in protein crystallography for the first time.These two functions include both structure factor amplitudes and phases via the Fourier transform of electron density map.Results We carry out tests on synthetic data sets of known structures,varying the resolution and error,and draw the quality curves of electron density maps with theoretical,noisy and experimental diffraction data by two evaluation functions at different resolutions.The curves reveal the optimum structure and resolution of proteins clearly.Conclusions The work presented here offers new methods to evaluate the qualities of the electron density maps of proteins with slight differences,and brand new indicators to select the optimum diffraction resolution of protein structures.展开更多
基金supported by the National Natural Science Foundation of China(51978133,52100026,U20A20322,52170151,51978132)the Fundamental Research Funds for the Central Universities of China(2412021QD022)+1 种基金the Key Research and Development Project of Hainan Province(ZDYF2022SHFZ298)the Industrialization Cultivation Project of Jilin Provincial Department of Education(JJKH20221174CY)。
文摘The occurrence of ultrafiltration(UF)membrane fouling frequently hampers the sustainable advancement of UF technology.Reactive self-cleaning UF membranes can effectively alleviate the problem of membrane fouling.Nevertheless,the self-cleaning process may accelerate membrane aging.Addressing these concerns,we present an innovative design concept for composite self-healing materials based on self-cleaning UF membranes.To begin,TiO_(2)nanoparticles were incorporated into the polymer molecular structure via molecular design,resulting in the synthesis of TiO_(2)/carboxyl-polyether sulfone(PES)hybrid materials.Subsequently,the nonsolvent-induced phase inversion technique was employed to prepare a novel of UF membrane.Lastly,a polyvinyl alcohol(PVA)hydrogel coating was applied to the hybrid UF membrane surface to create PVA@TiO_(2)/carboxyl-PES self-healing reactive UF membranes.By establishing a covalent bond,the TiO_(2)nanoparticles were effectively and uniformly dispersed within the UF membrane,leading to exceptional self-cleaning properties.Furthermore,the water-absorbing and swelling properties of PVA hydrogel,along with its capacity to form hydrogen bonds with water molecules,resulted in UF membranes with improved hydrophilicity and active self-healing abilities.The results demonstrated that the water contact angle of PVA@5%TiO_(2)/carboxyl-PES UF membrane was 43.1°.Following a 1-h exposure to simulated solar exposure,the water flux recovery ratio increased from 48.16%to 81.03%.Moreover,even after undergoing five cycles of 12-h simulated sunlight exposure,the UF membranes exhibited a consistent retention rate of over 97%,thus fully demonstrating their exceptional self-cleaning,antifouling,and selfhealing capabilities.We anticipate that the self-healing reactive UF membrane system will serve as a pioneering and comprehensive solution for the self-cleaning antifouling challenges encountered in UF membranes while also effectively mitigating the aging effects of reactive UF membranes.
基金supported by the National Natural Science Foundation of China,Nos.81801169 (to LXX),82071404 (to HC),81870952 (to HMW)。
文摘Promotion of new blood vessel formation is a new strategy for treating ischemic stroke.Non-coding miRNAs have been recently considered potential therapeutic targets for ischemic stroke.miR-181b has been shown to promote angiogenesis in hypoxia and traumatic brain injury model,while its effect on ischemic stroke remains elusive.In this study,we found that overexpression of miR-181b in brain microvascular endothelial cells subjected to oxygen-glucose deprivation in vitro restored cell prolife ration and enhanced angiogenesis.In rat models of focal cerebral ischemia,ove rexpression of miR-181b reduced infarction volume,promoted angiogenesis in ischemic penumbra,and improved neurological function.We further investigated the molecular mechanism by which miR-181b participates in angiogenesis after ischemic stroke and found that miR-181b directly bound to the 3’-UTR of phosphatase and tensin homolog(PTEN) mRNA to induce PTEN downregulation,leading to activation of the protein kinase B(Akt) pathway,upregulated expression of vascular endothelial growth facto rs,down-regulated expression of endostatin,and promoted angiogenesis.Taken togethe r,these results indicate that exogenous miR-181b exhibits neuroprotective effects on ischemic stro ke through activating the PTEN/Akt signal pathway and promoting angiogenesis.
文摘Causal inference is a powerful modeling tool for explanatory analysis,which might enable current machine learning to become explainable.How to marry causal inference with machine learning to develop explainable artificial intelligence(XAI)algorithms is one of key steps toward to the artificial intelligence 2.0.With the aim of bringing knowledge of causal inference to scholars of machine learning and artificial intelligence,we invited researchers working on causal inference to write this survey from different aspects of causal inference.This survey includes the following sections:“Estimating average treatment effect:A brief review and beyond”from Dr.Kun Kuang,“Attribution problems in counterfactual inference”from Prof.Lian Li,“The Yule–Simpson paradox and the surrogate paradox”from Prof.Zhi Geng,“Causal potential theory”from Prof.Lei Xu,“Discovering causal information from observational data”from Prof.Kun Zhang,“Formal argumentation in causal reasoning and explanation”from Profs.Beishui Liao and Huaxin Huang,“Causal inference with complex experiments”from Prof.Peng Ding,“Instrumental variables and negative controls for observational studies”from Prof.Wang Miao,and“Causal inference with interference”from Dr.Zhichao Jiang.
基金supported by the Specific Research Project of Health Pro Bono Sector, Ministry of Health, China (200802056)
文摘This study aimed to assess the reliability of experienced Chinese orthodontists in evaluating treatment outcome and to determine the correlations between three diagnostic information sources. Sixty-nine experienced Chinese orthodontic specialists each evaluated the outcome of orthodontic treatment of 108 Chinese patients. Three different information sources: study casts(SC), lateral cephalometric X-ray images(LX) and facial photographs(PH) were generated at the end of treatment for 108 patients selected randomly from six orthodontic treatment centers throughout China. Six different assessments of treatment outcome were made by each orthodontist using data from the three information sources separately and in combination. Each assessment included both ranking and grading for each patient. The rankings of each of the 69 judges for the 108 patients were correlated with the rankings of each of the other judges yielding 13 873 Spearman rs values, ranging from –0.08 to 10.85. Of these, 90% were greater than 0.4, showing moderate-to-high consistency among the 69 orthodontists. In the combined evaluations, study casts were the most significant predictive component(R250.86, P,0.000 1), while the inclusion of lateral cephalometric films and facial photographs also contributed to a more comprehensive assessment(R250.96, P,0.000 1). Grading scores for SC1LX and SC1PH were highly significantly correlated with those for SC1LX1PH(r(SC1LX)vs.(SC1LX1PH) 50.96, r(SC1PH)vs.(SC1LX1PH) 50.97), showing that either SC1LX or SC1PH is an excellent substitute for all three combined assessment.
基金financial support from the National Natural Science Foundation of China(Nos.21474014 and 22175111)Z.G.thanks financial support from the National Natural Science Foundation of China(No.21704013)+1 种基金China Postdoctoral Science Foundation(No.2017M611416)R.B.W.thanks for financial support from the National Postdoctoral Program for Innovative Talents(No.BX201700044).
文摘There is a great interest in developing microelectronic devices based on nanostructured conducting polymers that can selectively electro-couple analytes at high sensitivity and low power.Nanostructured conducting polymers have emerged as promising candidates for this technology due to their excellent stability with low redox potential,high conductivity,and selectivity endowed by chemical functionalization.However,it remains challenging to develop cost-effective and large-scale assembly approaches for functionalized conducting polymers in the practical fabrication of electronic devices.Here,we reported a straightforward waferscale assembly of nanostructured hexafluoroisopropanol functionalized poly(3,4-ethylenedioxythiophene)(PEDOT-HFIP)on smooth substrates.This approach is template-free,solution-processed,and adaptable to conductive and nonconductive substrates.By this approach,the nanostructured PEDOT-HFIPs could be easily integrated onto interdigitated electrodes with intimate ohmic contact.At the optimized space-to-volume ratio,we demonstrated a low-power,sensitive,and selective nerve agent sensing technology using this platform by detecting sarin vapor with a limit of detection(LOD)of 10 ppb and signal strength of 400 times the water interference at the same concentration,offering significant advantages over existing similar technologies.We envision that its easy scale-up,micro size,small power consumption,and combination of high sensitivity and selectivity make it attractive for various wearable platforms.
文摘This paper proposes a single-ended fault detection scheme for long transmission lines using support vector machine(SVM)for multi-terminal direct current systems based on modular multilevel converter(MMC-MTDC).The scheme overcomes existing detection difficulties in the protection of long transmission lines resulting from high grounding resistance and attenuation,and also avoids the sophisticated process of threshold value selection.The high-frequency components in the measured voltage extracted by a wavelet transform and the amplitude of the zero-mode set of the positive-sequence voltage are the inputs to a trained SVM.The output of the SVM determines the fault type.A model of a four-terminal DC power grid with overhead transmission lines is built in PSCAD/EMTDC.Simulation results of EMTDC confirm that the proposed scheme achieves 100%accuracy in detecting short-circuit faults with high resistance on long transmission lines.The proposed scheme eliminates mal-operation of DC circuit breakers when faced with power order changes or AC-side faults.Its robustness and time delay are also assessed and shown to have no perceptible effect on the speed and accuracy of the detection scheme,thus ensuring its reliability and stability.
基金supported by NSFC(22175111,21474014,21704013,and 51903149)the Program for Professor of Special Appointment(Eastern Scholar)at the Shanghai Institutions of Higher Learning(TP2019043)the Program of Shanghai Academic/Technology Research Leader(20XD1400100).
文摘Conducting polymers offer attractive mixed ionic-electronic conductivity,tunable interfacial barrier with metal,tissue matchable softness,and versatile chemical functionalization,making them robust to bridge the gap between brain tissue and electronic circuits.This review focuses on chemically revised conducting polymers,combined with their superior and controllable electrochemical performance,to fabricate long-term bioelectronic implants,addressing chronic immune responses,weak neuron attraction,and long-term electrocommunication instability challenges.Moreover,the promising progress of zwitterionic conducting polymers in bioelectronic implants(≥4 weeks stable implantation)is highlighted,followed by a comment on their current evolution toward selective neural coupling and reimplantable function.Finally,a critical forward look at the future of zwitterionic conducting polymers for in vivo bioelectronic devices is provided.
基金the National Natural Science Foundation of China(No.82101498 to XW)STI2030-Major Prjects of China(No.20212D0201801 to PH)+1 种基金National Natural Science Foundation of China(No.82171917 to PH,No.82090034 and 31970979 to KW and 32071054 to YT)the 2021 Youth Foundation Training Program of the First Affiliated Hospital of Anhui Medical University(No.2021kj19 to XW).
文摘Background Previous studies havedemonstrated that excitatory repetitive transcranial magnetic stimulation(rTMS)can improve the cognitive function of patients with Alzheimer's disease(AD).Intermittent theta burst stimulation(iTBS)is a novel excitatory rTMS protocol for brain activity stimulation with the ability to induce long-term potentiation-like plasticity and represents a promising treatment for AD.However,the long-term effects of iTBS on cognitive decline and brain structure in patients with AD areunknown.Aims We aimed to explore whether repeating accelerated iTBS every three months could slow down the cognitive decline in patients with AD.Methods In this randomised,assessor-blinded,controlled trial,iTBS was administered to the left dorsolateral prefrontal cortex(DLPFC)of 42 patients with AD for 14days every 13weeks.Measurements included the Montreal Cognitive Assessment(MoCA),a comprehensive neuropsychological battery,and the grey matter volume(GMV)of the hippocampus.Patients were evaluated at baseline and after follow-up.The longitudinal pipeline of the Computational Anatomy Toolbox for SPM was used to detect significant treatment-related changes over time.Results The iTBS group maintained MoCA scores relative to the control group(t=3.26,p=0.013)and reduced hippocampal atrophy,which was significantly correlated with global degeneration scale changes.The baseline Mini-Mental State Examination(MMSE)score,apolipoprotein E genotype and Clinical Dementia Rating were indicative of MoCA scores at follow-up.Moreover,the GMV of the left(t=0.08,p=0.996)and right(t=0.19,p=0.977)hippocampus were maintained in the active group but significantly declined in the control group(left:t=4.13,p<0.001;right:t=5.31,p<0.001).GMV change in the left(r=0.35,p=0.023)and right(r=0.36,p=0.021)hippocampus across the intervention positively correlated with MoCA changes;left hippocampal GMV change was negatively correlated with global degeneration scale(r=-0.32,p=0.041)changes.Conclusions DLPFC-iTBS maybe a feasible and easy-to-implement non-pharmacological intervention to slow down the progressive decline of overall cognition and quality of life in patients with AD,providing a new AD treatment option.Trial registration number NCT04754152.
基金financially supported by National Natural Science Foundation of China (NSFC NO. 41302196 and 51238001)supported by the Fundamental Research Funds for the Central Universities (NO. 14QNJJ026)
文摘Transport behaviors of graphene oxide nanoparticles(GONPs) in saturated porous media were examined as a function of the presence and concentration of anionic surfactant(SDBS)and non-ionic surfactant(Triton X-100) under different ionic strength(IS). The results showed that the GONPs were retained obviously in the sand columns at both IS of 50 and200 mmol/L, and they were more mobile at lower IS. The presence and concentration of surfactants could enhance the GONP transport, particularly as observed at higher IS. It was interesting to see that the GONP transport was surfactant type dependent, and SDBS was more effective to facilitate GONP transport than Triton X-100 in our experimental conditions. The advection–dispersion–retention numerical modeling followed this trend and depicted the difference quantitatively. Derjaguin–Landau–Verwey–Overbeek(DLVO)interaction calculations also were performed to interpret these effects, indicating that secondary minimum deposition was critical in this study.
基金supported by the National Natural Science Foundation of China (81671207,81701895,and 81501048)the Shanghai Jiao Tong University Medicine-Engineering Research Fund (YG2016QN20).
文摘Aloin is a small-molecule drug well known for its protective actions in various models of damage.Traumatic brain injury(TBI)-induced cerebral edema from secondary damage caused by disruption of the blood-brain barrier(BBB) often leads to an adverse prognosis.Since the role of aloin in maintaining the integrity of the BBB after TBI remains unclear,we explored the protective effects of aloin on the BBB using in vivo and in vitro TBI models.Adult male C57 BL/6 mice underwent controlled cortical impact injury,and mouse brain capillary endothelial bEnd.3 cells underwent biaxial stretch injury,then both received aloin treatment.In the animal experiments,we found 20 mg/kg aloin to be the optimum concentration to decrease cerebral edema,decrease disruption of the BBB,and improve neurobehavioral performance after cortical impact injury.In the cellular studies,the optimum concentration of 40 μg/mL aloin reduced apoptosis and reversed the loss of tight junctions by reducing the reactive oxygen species levels and changes in mitochondrial membrane potential after stretch injury.The mechanisms may be that aloin downregulates the phosphorylation of p38 mitogen-activated protein kinase,the activation of p65 nuclear factor-kappa B,and the ratios of B cell lymphoma(Bcl)-2-associated X protein/Bcl-2 and cleaved caspase-3/caspase-3.We conclude that aloin exhibits these protective effects on the BBB after TBI through its anti-oxidative stress and anti-apoptotic properties in mouse brain capillary endothelial cells.Aloin may thus be a promising therapeutic drug for TBI.
基金financially supported by the National Natural Science Foundation of China(No.21204002)Specialized Research Fund for the Doctoral Program of Higher Education(No.20111102120050)+1 种基金Program for New Century Excellent Talents in Universities(2010)the Fundamental Research Funds for the Central Universities
文摘pH-sensitive wettability of polystyrene-b-poly(4-vinylpyridine)(PS-b-P4VP) self assembled films, exhibiting superoleophobicity under water and hydrophilicity at low pH value, and oleophobicity under water and hydrophobicity at neutral condition, has been realized. The wettability properties resulted from the surface topological and chemical transition, which were confirmed by in situ AFM measurements under water at different pH. At low pH, P4VP chains, which were confined in the hexagonal-packed nanodomains, got protonated into a swollen state, while at high pH, P4VP chains were deprotonated into a collapsed state. The reversible protonation/deprotonation procedure on the molecular scale leads to surface topological and chemical transition, thereby pH-sensitive wettability.
基金financial support from the National Key Research and Development Program of China(2017YFA0206904,2017YFA0206900)start-up fund of Changchun Institute of Applied Chemistry,Chinese Academy of Sciences
文摘The ionic conductivity and the mechanical strength are two key factors for the performance of poly(ethylene oxide)(PEO) based polyelectrolytes. However, crystallized PEO suppresses ion conductivity at low temperature and melted PEO has low mechanical strength at high temperature. Here, random binary brush copolymer composed of PEO-and polystyrene(PS)-based side chains is synthesized. PEO crystallinity is suppressed by the introduction of PS brushes. Doping with lithium trifluoromethanesulfonate(Li Tf) induces microphase separation. Due to a random arrangement of the brushes, the microphase segregation is incomplete even at high salt loading, which provides both high ionic conductivity and high mechanical strength at room temperature. These results provide opportunities for the design of polymeric electrolytes to be used at room temperature.
基金the National Natural Science Foundation of China(31570744).
文摘Background The search of heavy atoms is crucial to the de novo determination of protein structures.Typically,the difference Patterson map is calculated as a first step to solve substructure.However,the pseudo-peaks and noises inherent in such maps arising from the high symmetry and large size of protein structures accompanied with the data collection errors inevitably pose a challenge in accurate real space-based substructure determination.Purpose In order to mitigate such pseudo-peaks and noises and further improve signal-to-noise ratio(SNR)of the difference Patterson map,the noise and artifact suppression using resampling(NASR)method originally proposed in nuclear magnetic resonance is introduced into protein crystallography in this work to optimize the difference Patterson map.Methods The NASR method makes use of the statistical learning theory,which in this work repeatedly samples a fixed portion of diffraction data(sub-dataset)randomly followed by a statistical analysis of the multiple calculated difference Patterson maps to discard pseudo-peaks and noises.Its feasibility is based on the fact that the true vector peaks of the heavy atoms keep static in the multiple random sub-datasets,whereas the pseudo-peaks and noises fluctuate remarkably.And the key of this method lies in the design of a weighting function to distinguish true vector peaks from pseudo-peaks and noises,as well as a proper selection of the parameters associated with the function.Results The introduced NASR method is both numerically and experimentally demonstrated to be feasible in suppressing spurious peaks and non-correlative noises intrinsic to the difference Patterson maps.As a result,the SNR of the difference Patterson maps can be enhanced to some extent to facilitate real space-based substructure determination.Conclusion It is therefore anticipated that the proposed method may provide a meaningful insight into how to denoise the difference Patterson maps,which in turn assists in locating heavy atoms and further facilitates de novo protein structure determination.
基金financially supported by the grants from Ph.D.Program Foundation of Ministry of Education of China(No.20120061110017)
文摘Novel functional hyperbranched poly(aryl ether ketone)s(HPAEKs) bonded with nonlinear optical chromophores(meso-tetrakis(4-hydroxyphenyl) porphyrin, THPP and its metal derivatives) were synthesized and characterized by 1H-NMR and UV-Vis absorption spectra. The incorporation of chromophores into HPAEKs endowed HPAEKs novel NLO and OL properties. Indeed, dendritic architecture allowed for maximum dispersion of the chromophores, avoided aggregation, more optical limiting property was obtained. Simultaneously, they retained the excellent properties of the materials, particularly in thermal stability. Their optical properties were evaluated by nonlinear optical analyses and optical limiting. The results showed that these polymers possessed good optical limiting(OL) property and large nonlinear optical(NLO) susceptibilities(ca. 10 12esu). All polymers containing chromophores presented excellent thermal stability(DT5 > 524.17 °C).
基金the National Natural Science Foundation of China(81974382)the Major Scientific and Technological Innovation Projects in Hubei Province(2018ACA136)COVID-19 Program of Huazhong University of Science and Technology(2020kfyXGYJ099)。
基金This work was financially supported by the grants from the Strategic Priority Research Program of CAS(XDB08030103)the National Natural Science Foundation of China(31570744,31670059).
文摘Background Recent advances in serial femtosecond crystallography(SFX)using X-ray free electron lasers(XFELs)have facilitated accurate structure determination for biological macromolecules.However,given the many fluctuations inherent in SFX,the acquisition of SFX data of sufficiently high quality still remains challenging.Method Aimed at enhancing the accuracy of SFX data,this study proposes an iterative refinement method to optimally match pairs of the observed and predicted reflections on the detector plane.This method features a combination of detector geometry optimization and diffraction model refinement in an alternate manner,concomitant with a cycle-by-cycle peak selection procedure.Result To demonstrate whether this iterative method is convergent and feasible,both numerical simulations and experimental tests have been performed.The results reveal that this method can gradually improve overall quality of the integrated SFX data and therefore accelerate the convergence of Monte Carlo integration,while simultaneously suppressing correlations inherent in certain parameters and precluding outliers to some extent during the refinement.Conclusion We have demonstrated that our iterative refinement method is applicable to both simulated and experimental SFX data.It is expected that this method could provide meaningful insights into the refinement of SFX data and take the step forward toward more accurate Monte Carlo integration.
基金This work was financially supported by grants from the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB08030103)the National Natural Science Foundation of China(31570744)the National Key Research and Development Project(2017YFA0504900).
文摘Background Finding methods to judge the quality of X-ray crystallographic information is an active research topic.The quality of electron density maps reconstructed by Fourier transform is always limited by the finite resolution,the amplitude/phase error and the completeness of diffraction data.At present,the R value and effective resolution are common ways of evaluating the quality of electron density maps.Unfortunately,the current evaluation methods are only dependent on diffraction amplitude,without any phase information.Methods Advanced evaluation functions in real space are designed to estimate the electron density map quality.The electron density map definition evaluation function relies on the atomicity of the electron density distribution.We use the power spectrum electron density entropy in protein crystallography for the first time.These two functions include both structure factor amplitudes and phases via the Fourier transform of electron density map.Results We carry out tests on synthetic data sets of known structures,varying the resolution and error,and draw the quality curves of electron density maps with theoretical,noisy and experimental diffraction data by two evaluation functions at different resolutions.The curves reveal the optimum structure and resolution of proteins clearly.Conclusions The work presented here offers new methods to evaluate the qualities of the electron density maps of proteins with slight differences,and brand new indicators to select the optimum diffraction resolution of protein structures.
