Although previous studies have demonstrated that transcranial focused ultrasound stimulation protects the ischemic brain,clear criteria for the stimulation time window and intensity are lacking.Electrical impedance to...Although previous studies have demonstrated that transcranial focused ultrasound stimulation protects the ischemic brain,clear criteria for the stimulation time window and intensity are lacking.Electrical impedance tomography enables real-time monitoring of changes in cerebral blood perfusion within the ischemic brain,but investigating the feasibility of using this method to assess post-stroke rehabilitation in vivo remains critical.In this study,ischemic stroke was induced in rats through middle cerebral artery occlusion surgery.Transcranial focused ultrasound stimulation was used to treat the rat model of ischemia,and electrical impedance tomography was used to measure impedance during both the acute stage of ischemia and the rehabilitation stage following the stimulation.Electrical impedance tomography results indicated that cerebral impedance increased after the onset of ischemia and decreased following transcranial focused ultrasound stimulation.Furthermore,the stimulation promoted motor function recovery,reduced cerebral infarction volume in the rat model of ischemic stroke,and induced the expression of brain-derived neurotrophic factor in the ischemic brain.Our results also revealed a significant correlation between the impedance of the ischemic brain post-intervention and improvements in behavioral scores and infarct volume.This study shows that daily administration of transcranial focused ultrasound stimulation for 20 minutes to the ischemic hemisphere 24 hours after cerebral ischemia enhanced motor recovery in a rat model of ischemia.Additionally,our findings indicate that electrical impedance tomography can serve as a valuable tool for quantitatively evaluating rehabilitation after ischemic stroke in vivo.These findings suggest the feasibility of using impedance data collected via electrical impedance tomography to clinically assess the effects of rehabilitatory interventions for patients with ischemic stroke.展开更多
Background:Platinum can cause chemotherapy-related cognitive impairment.Low-intensity focused ultrasound(LIFUS)is a promising noninvasive physical stimulation method with a unique advantage in neurological rehabilitat...Background:Platinum can cause chemotherapy-related cognitive impairment.Low-intensity focused ultrasound(LIFUS)is a promising noninvasive physical stimulation method with a unique advantage in neurological rehabilitation.We aimed to investigate whether LIFUS can alleviate cisplatin-induced cognitive impairment in rats and explore the related neuropatho-logical mechanisms.Methods:After confirming the target position for LIFUS treatment in 18 rats,64 rats were randomly divided into four groups:control,model,sham,and LIFUS groups.Before and after LIFUS treatment,detailed biological behavioral assessments and magnetic resonance imaging were performed.Finally,the rats were euthanized,and relevant histopathological and molecular biological experiments were conducted and analyzed.Results:In the Morris water maze,the model group showed fewer platform crossings(1.250.93 vs.5.691.58),a longer escape latency(41.6536.55 s vs.6.382.11 s),and a lower novel object recognition index(29.7711.83 vs.83.695.67)than the control group.LIFUS treatment improved these metrics,with more platform crossings(3.130.34),a higher recognition index(65.588.71),and a shorter escape latency(6.452.27 s).Longitudinal analysis of the LIFUS group further confirmed these improvements.Neuroimaging revealed significant differences in diffusion tensor imaging metrics of specific brain regions pre-and post-LIFUS.Moreover,neuropathology showed higher dendritic spine density,less myelin loss,fewer apoptotic cells,more synapses,and less mitochondrial autophagy after LIFUS treatment.The neuroimaging indicators were correlated with behavioral improvements,highlighting the potential of LIFUS for alleviating cognitive impairment(as demonstrated through imaging and analysis).Our investigation of the molecular biological mechanisms revealed distinct protein expression patterns in the hippocampus and its subregions.In the model group,glial fibrillary acidic protein(GFAP)and ionized calcium-binding adaptor molecule 1(IBA1)expression levels were elevated across the hippocampus,whereas neuronal nuclei(NeuN)expression was reduced.Subregional analysis revealed higher GFAP and IBA1 and lower NeuN,especially in the dentate gyrus subregion.Moreover,positive cell areas were larger in the cornu ammonis(CA)1,CA2,CA3,and dentate gyrus regions.In the CA2 and CA3,significant differences among the groups were observed in GFAP-positive cell counts and areas,and there were variations in NeuN expression.Conclusions:Our results suggest that LIFUS can reverse cisplatin-induced cognitive impairments.The neuroimaging findings were consistent with the behavioral and histological results and suggest a neuropathological basis that supports further research into the clinical applications of LIFUS.Furthermore,LIFUS appeared to enhance the plasticity of neuronal synapses in the rat hippocampus and reduce hippocampal inflammation.These findings highlight the clinical potential of LIFUS as an effective,noninvasive therapeutic strategy and monitoring tool for chemotherapy-induced cognitive deficits.展开更多
Facial expression datasets commonly exhibit imbalances between various categories or between difficult and simple samples.This imbalance introduces bias into feature extraction within facial expression recognition(FER...Facial expression datasets commonly exhibit imbalances between various categories or between difficult and simple samples.This imbalance introduces bias into feature extraction within facial expression recognition(FER)models,which hinders the algorithm’s comprehension of emotional states and reduces the overall recognition accuracy.A novel FER model is introduced to address these issues.It integrates rebalancing mechanisms to regulate attention consistency and focus,offering enhanced efficacy.Our approach proposes the following improvements:(i)rebalancing weights are used to enhance the consistency between the heatmaps of an original face sample and its horizontally flipped counterpart;(ii)coefficient factors are incorporated into the standard cross entropy loss function,and rebalancing weights are incorporated to fine-tune the loss adjustment.Experimental results indicate that the FER model outperforms the current leading algorithm,MEK,achieving 0.69%and 2.01%increases in overall and average recognition accuracies,respectively,on the RAF-DB dataset.The model exhibits accuracy improvements of 0.49%and 1.01%in the AffectNet dataset and 0.83%and 1.23%in the FERPlus dataset,respectively.These outcomes validate the superiority and stability of the proposed FER model.展开更多
President Xi Jinping’s message at China’s annual“two sessions”underpins the role of scientific and technological innovation and education in promoting national development.IN this year’s“two sessions,”the annua...President Xi Jinping’s message at China’s annual“two sessions”underpins the role of scientific and technological innovation and education in promoting national development.IN this year’s“two sessions,”the annual meetings of China’s top legislature and the top political advisory body.展开更多
Drawing upon self-determination theory,this study examines the effects of vicarious abusive supervision on third-party’s self-efficacy and task performance within organizational contexts.Data were collected via surve...Drawing upon self-determination theory,this study examines the effects of vicarious abusive supervision on third-party’s self-efficacy and task performance within organizational contexts.Data were collected via surveys from 337 employees across diverse organizations.The results indicate that vicarious abusive supervision significantly undermines both self-efficacy and task performance among employees who are indirectly exposed to such behavior but not directly targeted.Furthermore,self-efficacy serves as a mediator between vicarious abusive supervision and task performance;however,this mediating effect is attenuated for employees with a high promotion focus.These findings provide valuable theoretical and practical insights,particularly in the domain of organizational behavior,by emphasizing the critical role of promotion focus in mitigating the negative effects of vicarious abusive supervision.This research contributes to the organizational behavior literature by shifting the focus from the traditional supervisor-subordinate dynamic to a third-party perspective,thereby enriching our understanding of how vicarious abusive supervision impacts employees within organizational settings.The study underscores the importance of self-efficacy and promotion focus as key factors in unethical leadership contexts.展开更多
Efficient elastic wave focusing is crucial in materials and physical engineering.Elastic coding metasurfaces,which are innovative planar artificial structures,show great potential for use in the field of wave focusing...Efficient elastic wave focusing is crucial in materials and physical engineering.Elastic coding metasurfaces,which are innovative planar artificial structures,show great potential for use in the field of wave focusing.However,elastic coding lenses(ECLs)still suffer from low focusing performance,thickness comparable to wavelength,and frequency sensitivity.Here,we consider both the structural and material properties of the coding unit,thus realizing further compression of the thickness of the ECL.We chose the simplest ECL,which consists of only two encoding units.The coding unit 0 is a straight structure constructed using a carbon fiber reinforced composite material,and the coding unit 1 is a zigzag structure constructed using an aluminum material,and the thickness of the ECL constructed using them is only 1/8 of the wavelength.Based on the theoretical design,the arrangement of coding units is further optimized using genetic algorithms,which significantly improves the focusing performance of the lens at different focus and frequencies.This study provides a more effective way to control vibration and noise in advanced structures.展开更多
Transcranial focused ultrasound(tFUS)is an emerging modality with strong potential for non-invasively treating brain disorders.However,the inhomogeneity and complex structure of the skull induce substantial phase aber...Transcranial focused ultrasound(tFUS)is an emerging modality with strong potential for non-invasively treating brain disorders.However,the inhomogeneity and complex structure of the skull induce substantial phase aberrations and pressure attenuation;these can distort and shift the acoustic focus,thus hindering the efficiency of tFUS therapy.To achieve effective treatments,phased array transducers combined with aberration correction algorithms are commonly implemented.The present report aims to provide a comprehensive review of the current methods used for tFUS phase aberration correction.We first searched the PubMed and Web of Science databases for studies on phase aberration correction algorithms,identifying 54 articles for review.Relevant information,including the principles of algorithms and refocusing performances,were then extracted from the selected articles.The phase correction algorithms involved two main steps:acoustic field estimation and transmitted pulse adjustment.Our review identified key benchmarks for evaluating the effectiveness of these algorithms,each of which was used in at least three studies.These benchmarks included pressure and intensity,positioning error,focal region size,peak sidelobe ratio,and computational efficiency.Algorithm performances varied under different benchmarks,thus highlighting the importance of application-specific algorithm selection for achieving optimal tFUS therapy outcomes.The present review provides a thorough overview and comparison of various phase correction algorithms,and may offer valuable guidance to tFUS researchers when selecting appropriate phase correction algorithms for specific applications.展开更多
This paper explores the phenomenon of fluid resonance occurring within a narrow gap between a vessel and a vertical wharf, taking ships berthing in front of a gravity wharf as the research background. Using the open-s...This paper explores the phenomenon of fluid resonance occurring within a narrow gap between a vessel and a vertical wharf, taking ships berthing in front of a gravity wharf as the research background. Using the open-source software Open FOAM~?, a two-dimensional viscous-flow numerical wave flume was developed to simulate the fluid resonant motions induced by transient focused wave groups with different spectral peak periods and wave amplitudes. The results indicate that for all the incident focused wave amplitudes considered, the amplitudes of the free surface elevation in the gap, horizontal wave force and moment all exhibit a bimodal variation trend with increasing spectral peak period. The peak values of the above amplitude-period curve appear near the resonant period of the first and second harmonic components of the free surface elevation. However, the variation in the vertical wave force versus the spectral peak period presents different patterns. In addition, the first-to fourth-order harmonic components in the wave surface and forces are further examined via the four-phase combination method. The results show that the first-to secondorder harmonic components play a dominant role in the overall amplitude.展开更多
Dynamically tunable terahertz(THz)beam focusing plays a critical role in emerging applications including reconfigurable imaging,localized spectral analysis,and micro-machining.Conventional methods,however,frequently e...Dynamically tunable terahertz(THz)beam focusing plays a critical role in emerging applications including reconfigurable imaging,localized spectral analysis,and micro-machining.Conventional methods,however,frequently employ complex wavefront modulators and external control algorithms,resulting in increased system footprint and limited tuning efficiency.In this work,we present an all-silicon mechanically rotatable cascaded metasurface capable of dynamic THz beam focusing.By independently adjusting the relative rotation angles between the two metasurface layers,real-time repositioning of the focal spot is achieved for orthogonal circular polarization channels.The proposed design facilitates polarization-division multiplexing without requiring external algorithms or active materials while preserving high focusing efficiency and beam quality across a predefined focal plane.Numerical simulations reveal a quasi-linear shift of the focal position with the rotation angle,with stable focusing efficiency and full-width at half-maximum observed in both polarization channels.This strategy offers an efficient and reliable approach to dynamic wavefront control for compact,reconfigurable THz imaging,sensing,and communication systems.展开更多
Adjustable or programmable metamaterials offer versatile functions,while the complex multi-dimensional regulation increases workload,and hinders their applications in practical scenarios.To address these challenges,we...Adjustable or programmable metamaterials offer versatile functions,while the complex multi-dimensional regulation increases workload,and hinders their applications in practical scenarios.To address these challenges,we present a mechanically programmable acoustic metamaterial for real-time focal tuning via one-dimensional phase-gradient modulation in this paper.The device integrates a phase gradient structure with concave cavity channels and an x-shaped telescopic mechanical framework,enabling dynamic adjustment of inter-unit spacing(1 mm-3 mm)through a microcontroller-driven motor.By modulating the spacing between adjacent channels,the phase gradient is precisely controlled,allowing continuous focal shift from 50 mm to 300 mm along the x-axis at 7500 Hz.Broadband focusing is also discussed in the range6800 Hz-8100 Hz,with transmission coefficients exceeding 0.5,ensuring high efficiency and robust performance.Experimental results align closely with simulations,validating the design's effectiveness and adaptability.Unlike conventional programmable metamaterials requiring multi-dimensional parameter optimization,this approach simplifies real-time control through single-axis mechanical adjustment,significantly reducing operational complexity.Due to the advantages of broadband focusing,simple control mode,real-time monitoring,and so on,the device may have extensive applications in the fields of acoustic imaging,nondestructive testing,ultrasound medical treatment,etc.展开更多
AIM:To assess visual outcomes and satisfaction of a non-diffractive extended depth of focus(EDOF)intraocular lens(IOL)in individuals with ocular hypertension(OHT)and well-controlled mild glaucoma undergoing cataract s...AIM:To assess visual outcomes and satisfaction of a non-diffractive extended depth of focus(EDOF)intraocular lens(IOL)in individuals with ocular hypertension(OHT)and well-controlled mild glaucoma undergoing cataract surgery.METHODS:An investigator-initiated,single-center,prospective,interventional,noncomparative study conducted in Montreal,Canada.The study enrolled 31 patients(55 eyes)with OHT or mild glaucoma who received a non-diffractive EDOF IOL(Acrysof IQ Vivity).Participants underwent sequential cataract surgery with the Vivity IOL.Follow-up evaluations occurred at 1d,1,and 3mo postoperatively,assessing uncorrected distance,intermediate,and near visual acuity.Questionnaires(QUVID:Questionnaire for visual disturbances and IOLSAT:Intraocular lens satisfaction)were administered pre and post-operatively to measure visual disturbances and spectacle independence in various lighting.Safety parameters included intraocular pressure(IOP),glaucoma medications,spherical equivalence,mean deviation and pattern standard deviation or square root of lost variance on Octopus visual field.RESULTS:At 1 and 3mo postoperatively,significant improvements were observed in uncorrected distance and intermediate visual acuity.Spectacle independence was enhanced for distance and intermediate vision,especially in bright light settings.Spectacle-free intermediate vision was improved even in dim lighting.Visual disturbances,particularly glare symptoms,were reduced,and there was a notable decrease in IOP and glaucoma medication burden at 3mo.There was more hazy vision postoperatively with no impact on visual acuity and visual satisfaction.CONCLUSION:The non-diffractive EDOF lens improves distance and intermediate spectacle-free visual function in patients with OHT and well-controlled glaucoma.The findings highlight significant improvements in visual acuity,reduced glare,enhanced spectacle independence,and improved visual performance in different lighting conditions.展开更多
Techniques for manipulating nanodroplets lie at the core of numerous miniaturized systems in chemical and biological research endeavors.In this study,we introduce a versatile methodology for calculating the acoustic v...Techniques for manipulating nanodroplets lie at the core of numerous miniaturized systems in chemical and biological research endeavors.In this study,we introduce a versatile methodology for calculating the acoustic vortex field,integrating hybrid wave equation principles with ray acoustics.This approach demonstrates remarkable consistency between simulated results and experimental observations.Importantly,both theoretical analysis and experimental validation confirm that particles whose diameters match the wavelength(Mie particles)can be effectively trapped within a focused acoustic vortex field,rotating in circular trajectories centered at the vortex center.This research significantly expands the scope of acoustic vortex manipulation for larger particles and introduces a novel implementation strategy with potential applications in targeted drug delivery for clinical adjuvant therapy.展开更多
[Objectives]To investigate the effect of low-intensity focused ultrasound(LIFU)on rats with spinal cord injury(SCI)by examining the expression of calcineurin(CaN)and nuclear factor of activated T-cells(NFAT)in the inj...[Objectives]To investigate the effect of low-intensity focused ultrasound(LIFU)on rats with spinal cord injury(SCI)by examining the expression of calcineurin(CaN)and nuclear factor of activated T-cells(NFAT)in the injured spinal cord region following LIFU intervention.[Methods]Twenty-four specific pathogen-free(SPF)female Wistar rats,aged 7-8 weeks(160-180 g),were selected.Six rats were randomly assigned to the sham-operated group(SHAM),undergoing laminectomy only without spinal cord injury.Spinal cord injury models were established in the remaining rats using a modified Allen s weight-drop method at the T10 thoracic vertebral level.The 18 rats with successful modeling were then randomly divided into the spinal cord injury model group(SCI group),LIFU treatment group 1(T1 group),and LIFU treatment group 2(T2 group),with six rats in each group.LIFU treatment(for T1 and T2 groups)commenced on day 4 after injury,administered once daily for 20 min per session,for a total of 11 consecutive days.Tissues were harvested on day 14.Changes in CaN and NFAT4 mRNA expression were assessed using quantitative polymerase chain reaction(qPCR).Changes in CaN and NFAT4 protein expression were evaluated by Western blot analysis.[Results]qPCR analysis revealed that compared to the SHAM group,mRNA expression levels of both CaN and NFAT4 were decreased in the SCI group;compared to the SCI group,mRNA expression levels of CaN and NFAT4 were increased in both the T1 and T2 groups;furthermore,compared to the T1 group,mRNA expression levels of CaN and NFAT4 were higher in the T2 group.Western Blot analysis showed that compared to the SHAM group,protein expression levels of both CaN and NFAT4 were downregulated in the SCI group;compared to the SCI group,protein expression levels of CaN and NFAT4 were increased in both the T1 and T2 groups;moreover,compared to the T1 group,protein expression levels of CaN and NFAT4 were higher in the T2 group.[Conclusions]LIFU may contribute to functional recovery in SCI rats by modulating the expression levels of CaN and NFAT4.展开更多
基金supported by the Fundamental Research Funds for the Central Universities,Nos.G2021KY05107,G2021KY05101the National Natural Science Foundation of China,Nos.32071316,32211530049+1 种基金the Natural Science Foundation of Shaanxi Province,No.2022-JM482the Education and Teaching Reform Funds for the Central Universities,No.23GZ230102(all to LL and HH).
文摘Although previous studies have demonstrated that transcranial focused ultrasound stimulation protects the ischemic brain,clear criteria for the stimulation time window and intensity are lacking.Electrical impedance tomography enables real-time monitoring of changes in cerebral blood perfusion within the ischemic brain,but investigating the feasibility of using this method to assess post-stroke rehabilitation in vivo remains critical.In this study,ischemic stroke was induced in rats through middle cerebral artery occlusion surgery.Transcranial focused ultrasound stimulation was used to treat the rat model of ischemia,and electrical impedance tomography was used to measure impedance during both the acute stage of ischemia and the rehabilitation stage following the stimulation.Electrical impedance tomography results indicated that cerebral impedance increased after the onset of ischemia and decreased following transcranial focused ultrasound stimulation.Furthermore,the stimulation promoted motor function recovery,reduced cerebral infarction volume in the rat model of ischemic stroke,and induced the expression of brain-derived neurotrophic factor in the ischemic brain.Our results also revealed a significant correlation between the impedance of the ischemic brain post-intervention and improvements in behavioral scores and infarct volume.This study shows that daily administration of transcranial focused ultrasound stimulation for 20 minutes to the ischemic hemisphere 24 hours after cerebral ischemia enhanced motor recovery in a rat model of ischemia.Additionally,our findings indicate that electrical impedance tomography can serve as a valuable tool for quantitatively evaluating rehabilitation after ischemic stroke in vivo.These findings suggest the feasibility of using impedance data collected via electrical impedance tomography to clinically assess the effects of rehabilitatory interventions for patients with ischemic stroke.
基金supported by the National Natural Science Foundation of China(82171908 and 82102015)the General Project of the Nanjing Medical Science and Technology Development Program(YKK21075)the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515140030).
文摘Background:Platinum can cause chemotherapy-related cognitive impairment.Low-intensity focused ultrasound(LIFUS)is a promising noninvasive physical stimulation method with a unique advantage in neurological rehabilitation.We aimed to investigate whether LIFUS can alleviate cisplatin-induced cognitive impairment in rats and explore the related neuropatho-logical mechanisms.Methods:After confirming the target position for LIFUS treatment in 18 rats,64 rats were randomly divided into four groups:control,model,sham,and LIFUS groups.Before and after LIFUS treatment,detailed biological behavioral assessments and magnetic resonance imaging were performed.Finally,the rats were euthanized,and relevant histopathological and molecular biological experiments were conducted and analyzed.Results:In the Morris water maze,the model group showed fewer platform crossings(1.250.93 vs.5.691.58),a longer escape latency(41.6536.55 s vs.6.382.11 s),and a lower novel object recognition index(29.7711.83 vs.83.695.67)than the control group.LIFUS treatment improved these metrics,with more platform crossings(3.130.34),a higher recognition index(65.588.71),and a shorter escape latency(6.452.27 s).Longitudinal analysis of the LIFUS group further confirmed these improvements.Neuroimaging revealed significant differences in diffusion tensor imaging metrics of specific brain regions pre-and post-LIFUS.Moreover,neuropathology showed higher dendritic spine density,less myelin loss,fewer apoptotic cells,more synapses,and less mitochondrial autophagy after LIFUS treatment.The neuroimaging indicators were correlated with behavioral improvements,highlighting the potential of LIFUS for alleviating cognitive impairment(as demonstrated through imaging and analysis).Our investigation of the molecular biological mechanisms revealed distinct protein expression patterns in the hippocampus and its subregions.In the model group,glial fibrillary acidic protein(GFAP)and ionized calcium-binding adaptor molecule 1(IBA1)expression levels were elevated across the hippocampus,whereas neuronal nuclei(NeuN)expression was reduced.Subregional analysis revealed higher GFAP and IBA1 and lower NeuN,especially in the dentate gyrus subregion.Moreover,positive cell areas were larger in the cornu ammonis(CA)1,CA2,CA3,and dentate gyrus regions.In the CA2 and CA3,significant differences among the groups were observed in GFAP-positive cell counts and areas,and there were variations in NeuN expression.Conclusions:Our results suggest that LIFUS can reverse cisplatin-induced cognitive impairments.The neuroimaging findings were consistent with the behavioral and histological results and suggest a neuropathological basis that supports further research into the clinical applications of LIFUS.Furthermore,LIFUS appeared to enhance the plasticity of neuronal synapses in the rat hippocampus and reduce hippocampal inflammation.These findings highlight the clinical potential of LIFUS as an effective,noninvasive therapeutic strategy and monitoring tool for chemotherapy-induced cognitive deficits.
基金support from the National Natural Science Foundation of China(Grant Number 62477023).
文摘Facial expression datasets commonly exhibit imbalances between various categories or between difficult and simple samples.This imbalance introduces bias into feature extraction within facial expression recognition(FER)models,which hinders the algorithm’s comprehension of emotional states and reduces the overall recognition accuracy.A novel FER model is introduced to address these issues.It integrates rebalancing mechanisms to regulate attention consistency and focus,offering enhanced efficacy.Our approach proposes the following improvements:(i)rebalancing weights are used to enhance the consistency between the heatmaps of an original face sample and its horizontally flipped counterpart;(ii)coefficient factors are incorporated into the standard cross entropy loss function,and rebalancing weights are incorporated to fine-tune the loss adjustment.Experimental results indicate that the FER model outperforms the current leading algorithm,MEK,achieving 0.69%and 2.01%increases in overall and average recognition accuracies,respectively,on the RAF-DB dataset.The model exhibits accuracy improvements of 0.49%and 1.01%in the AffectNet dataset and 0.83%and 1.23%in the FERPlus dataset,respectively.These outcomes validate the superiority and stability of the proposed FER model.
文摘President Xi Jinping’s message at China’s annual“two sessions”underpins the role of scientific and technological innovation and education in promoting national development.IN this year’s“two sessions,”the annual meetings of China’s top legislature and the top political advisory body.
文摘Drawing upon self-determination theory,this study examines the effects of vicarious abusive supervision on third-party’s self-efficacy and task performance within organizational contexts.Data were collected via surveys from 337 employees across diverse organizations.The results indicate that vicarious abusive supervision significantly undermines both self-efficacy and task performance among employees who are indirectly exposed to such behavior but not directly targeted.Furthermore,self-efficacy serves as a mediator between vicarious abusive supervision and task performance;however,this mediating effect is attenuated for employees with a high promotion focus.These findings provide valuable theoretical and practical insights,particularly in the domain of organizational behavior,by emphasizing the critical role of promotion focus in mitigating the negative effects of vicarious abusive supervision.This research contributes to the organizational behavior literature by shifting the focus from the traditional supervisor-subordinate dynamic to a third-party perspective,thereby enriching our understanding of how vicarious abusive supervision impacts employees within organizational settings.The study underscores the importance of self-efficacy and promotion focus as key factors in unethical leadership contexts.
基金Project supported by the National Natural Science Foundation of China(Grant No.12404531)the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province,China(Grant No.23KJB140011)。
文摘Efficient elastic wave focusing is crucial in materials and physical engineering.Elastic coding metasurfaces,which are innovative planar artificial structures,show great potential for use in the field of wave focusing.However,elastic coding lenses(ECLs)still suffer from low focusing performance,thickness comparable to wavelength,and frequency sensitivity.Here,we consider both the structural and material properties of the coding unit,thus realizing further compression of the thickness of the ECL.We chose the simplest ECL,which consists of only two encoding units.The coding unit 0 is a straight structure constructed using a carbon fiber reinforced composite material,and the coding unit 1 is a zigzag structure constructed using an aluminum material,and the thickness of the ECL constructed using them is only 1/8 of the wavelength.Based on the theoretical design,the arrangement of coding units is further optimized using genetic algorithms,which significantly improves the focusing performance of the lens at different focus and frequencies.This study provides a more effective way to control vibration and noise in advanced structures.
基金supported by Start-Up Grant From ShanghaiTech University,2021F0209-000-09Natural Science Foundation of Shanghai Municipality,23ZR1442000。
文摘Transcranial focused ultrasound(tFUS)is an emerging modality with strong potential for non-invasively treating brain disorders.However,the inhomogeneity and complex structure of the skull induce substantial phase aberrations and pressure attenuation;these can distort and shift the acoustic focus,thus hindering the efficiency of tFUS therapy.To achieve effective treatments,phased array transducers combined with aberration correction algorithms are commonly implemented.The present report aims to provide a comprehensive review of the current methods used for tFUS phase aberration correction.We first searched the PubMed and Web of Science databases for studies on phase aberration correction algorithms,identifying 54 articles for review.Relevant information,including the principles of algorithms and refocusing performances,were then extracted from the selected articles.The phase correction algorithms involved two main steps:acoustic field estimation and transmitted pulse adjustment.Our review identified key benchmarks for evaluating the effectiveness of these algorithms,each of which was used in at least three studies.These benchmarks included pressure and intensity,positioning error,focal region size,peak sidelobe ratio,and computational efficiency.Algorithm performances varied under different benchmarks,thus highlighting the importance of application-specific algorithm selection for achieving optimal tFUS therapy outcomes.The present review provides a thorough overview and comparison of various phase correction algorithms,and may offer valuable guidance to tFUS researchers when selecting appropriate phase correction algorithms for specific applications.
基金financially supported by the National Natural Science Foundation of China (Grant No. 52371277)the State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation (Tianjin University)(Grant No. HESS-2323)+2 种基金the Postgraduate Research&Practice Innovation Program of Jiangsu Province (Grant No. KYCX24_4071)the Guangdong Basic and Applied Basic Research Foundation (Grant No. 2023A1515010890)the Open foundation of Key Laboratory of Port.Waterway&Sedimentation Engineering (Grant No. Yk224001-1)。
文摘This paper explores the phenomenon of fluid resonance occurring within a narrow gap between a vessel and a vertical wharf, taking ships berthing in front of a gravity wharf as the research background. Using the open-source software Open FOAM~?, a two-dimensional viscous-flow numerical wave flume was developed to simulate the fluid resonant motions induced by transient focused wave groups with different spectral peak periods and wave amplitudes. The results indicate that for all the incident focused wave amplitudes considered, the amplitudes of the free surface elevation in the gap, horizontal wave force and moment all exhibit a bimodal variation trend with increasing spectral peak period. The peak values of the above amplitude-period curve appear near the resonant period of the first and second harmonic components of the free surface elevation. However, the variation in the vertical wave force versus the spectral peak period presents different patterns. In addition, the first-to fourth-order harmonic components in the wave surface and forces are further examined via the four-phase combination method. The results show that the first-to secondorder harmonic components play a dominant role in the overall amplitude.
基金supported by the National Natural Science Foundation of China(Grants U22A2008,12404484,12464016,and 62405219)the Double First Class Joint Special Key Project of Yunnan Science and Technology Department and Yunnan University(Grant 202401BF070001-012)Sichuan Provincial Science and Technology Support Program(Grant 25QNJJ2419).
文摘Dynamically tunable terahertz(THz)beam focusing plays a critical role in emerging applications including reconfigurable imaging,localized spectral analysis,and micro-machining.Conventional methods,however,frequently employ complex wavefront modulators and external control algorithms,resulting in increased system footprint and limited tuning efficiency.In this work,we present an all-silicon mechanically rotatable cascaded metasurface capable of dynamic THz beam focusing.By independently adjusting the relative rotation angles between the two metasurface layers,real-time repositioning of the focal spot is achieved for orthogonal circular polarization channels.The proposed design facilitates polarization-division multiplexing without requiring external algorithms or active materials while preserving high focusing efficiency and beam quality across a predefined focal plane.Numerical simulations reveal a quasi-linear shift of the focal position with the rotation angle,with stable focusing efficiency and full-width at half-maximum observed in both polarization channels.This strategy offers an efficient and reliable approach to dynamic wavefront control for compact,reconfigurable THz imaging,sensing,and communication systems.
基金supported by the National Natural Science Foundation of China(Grant No.12374416)。
文摘Adjustable or programmable metamaterials offer versatile functions,while the complex multi-dimensional regulation increases workload,and hinders their applications in practical scenarios.To address these challenges,we present a mechanically programmable acoustic metamaterial for real-time focal tuning via one-dimensional phase-gradient modulation in this paper.The device integrates a phase gradient structure with concave cavity channels and an x-shaped telescopic mechanical framework,enabling dynamic adjustment of inter-unit spacing(1 mm-3 mm)through a microcontroller-driven motor.By modulating the spacing between adjacent channels,the phase gradient is precisely controlled,allowing continuous focal shift from 50 mm to 300 mm along the x-axis at 7500 Hz.Broadband focusing is also discussed in the range6800 Hz-8100 Hz,with transmission coefficients exceeding 0.5,ensuring high efficiency and robust performance.Experimental results align closely with simulations,validating the design's effectiveness and adaptability.Unlike conventional programmable metamaterials requiring multi-dimensional parameter optimization,this approach simplifies real-time control through single-axis mechanical adjustment,significantly reducing operational complexity.Due to the advantages of broadband focusing,simple control mode,real-time monitoring,and so on,the device may have extensive applications in the fields of acoustic imaging,nondestructive testing,ultrasound medical treatment,etc.
文摘AIM:To assess visual outcomes and satisfaction of a non-diffractive extended depth of focus(EDOF)intraocular lens(IOL)in individuals with ocular hypertension(OHT)and well-controlled mild glaucoma undergoing cataract surgery.METHODS:An investigator-initiated,single-center,prospective,interventional,noncomparative study conducted in Montreal,Canada.The study enrolled 31 patients(55 eyes)with OHT or mild glaucoma who received a non-diffractive EDOF IOL(Acrysof IQ Vivity).Participants underwent sequential cataract surgery with the Vivity IOL.Follow-up evaluations occurred at 1d,1,and 3mo postoperatively,assessing uncorrected distance,intermediate,and near visual acuity.Questionnaires(QUVID:Questionnaire for visual disturbances and IOLSAT:Intraocular lens satisfaction)were administered pre and post-operatively to measure visual disturbances and spectacle independence in various lighting.Safety parameters included intraocular pressure(IOP),glaucoma medications,spherical equivalence,mean deviation and pattern standard deviation or square root of lost variance on Octopus visual field.RESULTS:At 1 and 3mo postoperatively,significant improvements were observed in uncorrected distance and intermediate visual acuity.Spectacle independence was enhanced for distance and intermediate vision,especially in bright light settings.Spectacle-free intermediate vision was improved even in dim lighting.Visual disturbances,particularly glare symptoms,were reduced,and there was a notable decrease in IOP and glaucoma medication burden at 3mo.There was more hazy vision postoperatively with no impact on visual acuity and visual satisfaction.CONCLUSION:The non-diffractive EDOF lens improves distance and intermediate spectacle-free visual function in patients with OHT and well-controlled glaucoma.The findings highlight significant improvements in visual acuity,reduced glare,enhanced spectacle independence,and improved visual performance in different lighting conditions.
基金Project supported by the National Key R&D Program of China(Grant No.2023YFE0201900)。
文摘Techniques for manipulating nanodroplets lie at the core of numerous miniaturized systems in chemical and biological research endeavors.In this study,we introduce a versatile methodology for calculating the acoustic vortex field,integrating hybrid wave equation principles with ray acoustics.This approach demonstrates remarkable consistency between simulated results and experimental observations.Importantly,both theoretical analysis and experimental validation confirm that particles whose diameters match the wavelength(Mie particles)can be effectively trapped within a focused acoustic vortex field,rotating in circular trajectories centered at the vortex center.This research significantly expands the scope of acoustic vortex manipulation for larger particles and introduces a novel implementation strategy with potential applications in targeted drug delivery for clinical adjuvant therapy.
文摘[Objectives]To investigate the effect of low-intensity focused ultrasound(LIFU)on rats with spinal cord injury(SCI)by examining the expression of calcineurin(CaN)and nuclear factor of activated T-cells(NFAT)in the injured spinal cord region following LIFU intervention.[Methods]Twenty-four specific pathogen-free(SPF)female Wistar rats,aged 7-8 weeks(160-180 g),were selected.Six rats were randomly assigned to the sham-operated group(SHAM),undergoing laminectomy only without spinal cord injury.Spinal cord injury models were established in the remaining rats using a modified Allen s weight-drop method at the T10 thoracic vertebral level.The 18 rats with successful modeling were then randomly divided into the spinal cord injury model group(SCI group),LIFU treatment group 1(T1 group),and LIFU treatment group 2(T2 group),with six rats in each group.LIFU treatment(for T1 and T2 groups)commenced on day 4 after injury,administered once daily for 20 min per session,for a total of 11 consecutive days.Tissues were harvested on day 14.Changes in CaN and NFAT4 mRNA expression were assessed using quantitative polymerase chain reaction(qPCR).Changes in CaN and NFAT4 protein expression were evaluated by Western blot analysis.[Results]qPCR analysis revealed that compared to the SHAM group,mRNA expression levels of both CaN and NFAT4 were decreased in the SCI group;compared to the SCI group,mRNA expression levels of CaN and NFAT4 were increased in both the T1 and T2 groups;furthermore,compared to the T1 group,mRNA expression levels of CaN and NFAT4 were higher in the T2 group.Western Blot analysis showed that compared to the SHAM group,protein expression levels of both CaN and NFAT4 were downregulated in the SCI group;compared to the SCI group,protein expression levels of CaN and NFAT4 were increased in both the T1 and T2 groups;moreover,compared to the T1 group,protein expression levels of CaN and NFAT4 were higher in the T2 group.[Conclusions]LIFU may contribute to functional recovery in SCI rats by modulating the expression levels of CaN and NFAT4.
