AIM:To evaluate the effects of microlens design of peripheral defocus modifying spectacle lenses(PDMSLs)and non-microlens design of PDMSLs on controlling myopia progression in children and adolescents.METHODS:A system...AIM:To evaluate the effects of microlens design of peripheral defocus modifying spectacle lenses(PDMSLs)and non-microlens design of PDMSLs on controlling myopia progression in children and adolescents.METHODS:A systematic search was carried out in the PubMed,Cochrane Library,Embase,CNKI,and Web of Science databases.The search targeted randomized controlled trials(RCTs)and cohort studies(CTs)that explored the effects of PDMSLs on myopia control among children and adolescents.The Cochrane risk-of-bias tool and the Newcastle-Ottawa Scale were employed to evaluate the risk of bias in the included studies.The published biases of the included studies were evaluated using Egger’s test.RESULTS:Nine studies(7 RCTs,2 CTs)were included,involving 4332 participants in the PDMSLs group and 7317 participants in the single vision lenses(SVLs)group.Metaanalysis showed that PDMSLs with microlens design had lower change in spherical equivalent refraction(SER)than SVLs at 6,12,18,and 24mo after wearing glasses,with reductions of 0.19 D(95%CI:0.14 to 0.24,P<0.00001),0.36 D(95%CI:0.25 to 0.46,P<0.00001),0.43 D(95%CI:0.32 to 0.55,P<0.00001),and 0.51 D(95%CI:0.33 to 0.69,P<0.00001),respectively.The changes in axial length(AL)were also lower in PDMSLs compared to SVLs,with reductions of-0.09 mm(95%CI:-0.13 to-0.04,P=0.0002),-0.15 mm(95%CI:-0.21 to-0.08,P<0.00001),-0.27 mm(95%CI:-0.34 to-0.20,P<0.00001),and-0.29 mm(95%CI:-0.38 to-0.20,P<0.00001),respectively.There was no significant difference between the non-microlens group and SVLs in controlling the changes of SER and AL in myopia(both P>0.05).CONCLUSION:The synthesized evidence indicates superior myopia management outcomes with microlens design of PDMSLs compared to both SVLs and nonmicrolens design of PDMSLs in children and adolescents.展开更多
AIM:To investigate the expressions of type I collagen, α2 integrin and β1 integrin in the posterior sclera of guinea pigs with defocus myopia and whether basic fibroblast growth factor (bFGF) injection inhibits the ...AIM:To investigate the expressions of type I collagen, α2 integrin and β1 integrin in the posterior sclera of guinea pigs with defocus myopia and whether basic fibroblast growth factor (bFGF) injection inhibits the formation and development of myopia by upregulating the expression of type I collagen, α2 integrin and β1 integrin. METHODS:After 14 days of treatment, the refractive state and axial length were measured and the levels of type I collagen, α2 integrin and β1 integrin were assayed in the posterior sclerae of groups of guinea pigs that wore a monocular-7D polymethylmethacrylate (PMMA) lens or had -7D lens wear followed by the peribulbar injection of Phosphate Buffer Solution (PBS) or bFGF. The untreated fellow eye served as a control. Guinea pigs with no treatment served as normal group. ·RESULTS:The results showed that 14 days of monocular defocus increased axial eye length and refraction, while bFGF delivery inhibited them markedly. Further, it was also found that the monocular-7D lens could decrease the levels of type I collagen, α2 integrin and β1 integrin expressions, while, unlike PBS, bFGF increased them significantly in comparison to contralateral control eyes and normal eyes. CONCLUSION:bFGF can prevent the formation anddevelopment of defocus myopia by upregulating the expressions of type I collagen, α2 integrin and β1 integrin. Taken together, our results demonstrate that bFGF promotes sclera remodeling to prevent myopia in guinea pigs.展开更多
The degraded parameters recognition is very important for the restoration of blurred images. There are two common types of blurs for most camera systems. One is the defocus blur due to the optical system's defocus...The degraded parameters recognition is very important for the restoration of blurred images. There are two common types of blurs for most camera systems. One is the defocus blur due to the optical system's defocus phenomenon and the other is the motion blur due to the relative movement between the objectives and the camera. Compared with the recognition for the blurred image with only one blur model, the parameter estimation for the picture combining defocus and motion blur models is a more complicated mission. A method was proposed for computer to estimate the parameters of defocus blur and motion blur in cepstrum area simultaneously. According to characters of both blur models in the frequency domain, an adjustment approach was suggested in the frequency area and then convert to the cepstrum field to increase the accuracy of measurement.展开更多
An offshore shoal or bar refracts ocean surface waves and causes wave focusing/defocusing on the adjacent beach. Wave focal patterns characterized by alongshore variations in wave height, wave angle, and breaking loca...An offshore shoal or bar refracts ocean surface waves and causes wave focusing/defocusing on the adjacent beach. Wave focal patterns characterized by alongshore variations in wave height, wave angle, and breaking location induce alongshore non-uniformities of wave setup and nearshore circulation, e.g., rip currents and alongshore currents, in the surfzone. A simplified analytic model for nearshore circulation generated by focused/defocused waves on a planar beach is developed and theoretical solutions are obtained using transport stream function and perturbations in alongshore distributions of wave height and wave angle at the breaker line. The analytic model suggests that alongshore currents are strongly affected by a pair of counter-rotating vortices generated shoreward of the wave focal zone. The vortices are persistent, and their strengths depend on the amplitudes of alongshore variations in wave height and wave angle. The alongshore gradient in wave height tends to intensify the vortices while the convergence of wave angle tends to weaken the vortices. Divergent flows associated with the vortices in the surfzone are intense, strengthening alongshore currents in the downstream of the wave focal zone and weakening alongshore currents or causing flows reversal in the upstream. Alongshore currents are modulated by rip currents associated with the wave focusing/defocusing patterns.展开更多
AIM: To evaluate the effectiveness of peripheral defocus spectacle lenses(PDLs) in myopia control. METHODS: Literature retrieval on Pub Med, Cochrane Library, Embase, and Web of Science databases, and the search time ...AIM: To evaluate the effectiveness of peripheral defocus spectacle lenses(PDLs) in myopia control. METHODS: Literature retrieval on Pub Med, Cochrane Library, Embase, and Web of Science databases, and the search time limit was from the establishment of each database to December 29, 2021 were conducted. Change of spherical equivalent refraction(SER) and axial change(AL) were extracted from the literatures that met the inclusion criteria, and Rev Man5.3 software was used for Meta-analysis. RESULTS: A total of 4 randomized controlled trials(RCTs) were included in this Meta-analysis, involving 770 myopic children. The results showed that PDLs could delay the progression of myopia in children with myopia compared with single vision spectacle lenses(SVLs;WMD=0.21 D, 95%CI: 0.01, 0.41, P=0.04). However, there was no significant difference in controlling the growth of axial length(AL) in myopic children(WMD=-0.10 mm, 95%CI:-0.21, 0.01, P=0.07). The results of the effectiveness of myopia control between the two spectacle lenses showed that PDLs were more effective in controlling the progression of myopia(OR=5.73, 95%CI: 2.58, 12.70, P<0.001) and delaying the growth of AL(OR=44.25, 95%CI: 8.84, 221.58, P<0.001) than SVLs, and the differences were statistically significant. CONCLUSION: PDLs can control the progression of myopia compared with SVLs, but cannot delay the growth of AL, and the effectiveness of PDLs in myopia control better than SVLs.展开更多
Three-beam laser internal coaxial wire feeding cladding is regarded as a promising additive manufacturing technique because it is highly efficient and controllable.In this study,the effects of the defocus distance on ...Three-beam laser internal coaxial wire feeding cladding is regarded as a promising additive manufacturing technique because it is highly efficient and controllable.In this study,the effects of the defocus distance on cladding using a three-beam laser with internal wire feeding are experimentally and numerically studied.A process map indicating the surface characteristics at different defocus distances with various parameter combinations was developed.The transmission characteristics including laser intensity,beam size,and laser spot distance of the three-beam laser at different defocus distances were analyzed using TracePro software.Based on the TracePro results as heat source,a three-dimensional transient finite element(FE)thermal model was formulated to predict the thermal field,temperature history and molten pool shape at different defocus distances.A molten pool with a flat bottom and low melting depth is generated when the defocus distance is−2.5 mm,whereas when this distance is−1.5 mm,a pool with a valley-shaped bond and high melting depth is formed.The simulated results of the temperature cycle and clad geometry are both validated and found to well agree with experimental measurements.The influence of the defocus distance on the microstructure and microhardness are discussed based on the temperature history and cooling rate.With the increase in the absolute defocus distance,the height and dilution of the clad decreased,whereas the width increased.In addition,the effects of defocus distance with various parameter combinations on clad geometry were explored using the formulated FE model.展开更多
AIM:To investigate the impact of multifocal gas permeable contact lens(MFGPCL)in various add power and distance/near area allocation on short-term changes of choroidal thickness(ChT),axial length(AL),and retinal defoc...AIM:To investigate the impact of multifocal gas permeable contact lens(MFGPCL)in various add power and distance/near area allocation on short-term changes of choroidal thickness(ChT),axial length(AL),and retinal defocus profile in young adults.METHODS:Seventeen young adults(2 males and 15 females;age 23.17±4.48y)were randomly assigned to wear two designs binocularly with a one-week washout period in between.Total of four MFGPCL designs were assessed.All designs were distance-center that varied in two add power(+1.50 and 3.00 D)and/or two distance zone(DZ)diameters(1.50 and 3.00 mm;design A:DZ 1.5/add 3.0,B:DZ 1.5/add 1.5,C:DZ 3.0/add 3.0,D:DZ 3.0/add 1.5).ChT,AL,and peripheral refraction data were collected on each subject at baseline,on days 1 and 7 of MFGPCL daily wear.ChT was assessed in four quadrants using a spectraldomain optical coherence tomography.RESULTS:AL was shortened by-26±44μm with lens C,-18±27μm with lens D,-13±29μm with lens A,and-8±30μm with lens B(all P<0.05).A significant overall increase in ChT was observed with all 4 designs(lens A:+6±6μm,B:+3±7μm,C:+8±7μm,and D:+8±7μm).Temporal and superior choroid exhibited more choroidal thickening associated with MFGPCL.All designs induced significant relative peripheral myopia(RPM)beyond the central 20o across the horizontal meridian in both nasal and temporal fields(P<0.05).CONCLUSION:MFGPCLs show a significant influence on ChT and AL,which are associated with significant increase in RPM after short-term wear.The reliability and feasibility of quantifying short-term changes in ChT support its use as a promising marker for the long-term efficacy of myopia-controlling treatments.展开更多
Reducing the defocus blur that arises from the finite aperture size and short exposure time is an essential problem in computational photography.It is very challenging because the blur kernel is spatially varying and ...Reducing the defocus blur that arises from the finite aperture size and short exposure time is an essential problem in computational photography.It is very challenging because the blur kernel is spatially varying and difficult to estimate by traditional methods.Due to its great breakthrough in low-level tasks,convolutional neural networks(CNNs)have been introdu-ced to the defocus deblurring problem and achieved significant progress.However,previous methods apply the same learned kernel for different regions of the defocus blurred images,thus it is difficult to handle nonuniform blurred images.To this end,this study designs a novel blur-aware multi-branch network(Ba-MBNet),in which different regions are treated differentially.In particular,we estimate the blur amounts of different regions by the internal geometric constraint of the dual-pixel(DP)data,which measures the defocus disparity between the left and right views.Based on the assumption that different image regions with different blur amounts have different deblurring difficulties,we leverage different networks with different capacities to treat different image regions.Moreover,we introduce a meta-learning defocus mask generation algorithm to assign each pixel to a proper branch.In this way,we can expect to maintain the information of the clear regions well while recovering the missing details of the blurred regions.Both quantitative and qualitative experiments demonstrate that our BaMBNet outperforms the state-of-the-art(SOTA)methods.For the dual-pixel defocus deblurring(DPD)-blur dataset,the proposed BaMBNet achieves 1.20 dB gain over the previous SOTA method in term of peak signal-to-noise ratio(PSNR)and reduces learnable parameters by 85%.The details of the code and dataset are available at https://github.com/junjun-jiang/BaMBNet.展开更多
Enormousmethods have been proposed for the detection and segmentation of blur and non-blur regions of the images.Due to the limited available information about blur type,scenario and the level of blurriness,detection ...Enormousmethods have been proposed for the detection and segmentation of blur and non-blur regions of the images.Due to the limited available information about blur type,scenario and the level of blurriness,detection and segmentation is a challenging task.Hence,the performance of the blur measure operator is an essential factor and needs improvement to attain perfection.In this paper,we propose an effective blur measure based on local binary pattern(LBP)with adaptive threshold for blur detection.The sharpness metric developed based on LBP used a fixed threshold irrespective of the type and level of blur,that may not be suitable for images with variations in imaging conditions,blur amount and type.Contrarily,the proposed measure uses an adaptive threshold for each input image based on the image and blur properties to generate improved sharpness metric.The adaptive threshold is computed based on the model learned through support vector machine(SVM).The performance of the proposed method is evaluated using two different datasets and is compared with five state-of-the-art methods.Comparative analysis reveals that the proposed method performs significantly better qualitatively and quantitatively against all of the compared methods.展开更多
Successful restoration of blurred images depends primarily on the knowledge about the degradationparameter.Defocus blur model in the frequency domain is characterized by concentric rings and the blurradius of the poin...Successful restoration of blurred images depends primarily on the knowledge about the degradationparameter.Defocus blur model in the frequency domain is characterized by concentric rings and the blurradius of the point spread function(PSF)can be identified conveniently in the frequency field for peopleby manual means rather than for computer.This paper introduces a practical method for computer to esti-mate the defocus blur parameter in cepstrum area.Fourier transform plays an intermediate role in the pathto cepstrum domain.We suggest a weighted adjustment operation in the frequency domain and then con-vert it to the cepstrum field to increase the accuracy of recognition.展开更多
I am Dr. David P Pifiero from the Department of Optics, Pharmacology and Anatomy of the University of Alicante and from the Department of Ophthalmology of Vithas Medimar （Oftalmar） and Vithas Virgen del Carmen （Qv...I am Dr. David P Pifiero from the Department of Optics, Pharmacology and Anatomy of the University of Alicante and from the Department of Ophthalmology of Vithas Medimar （Oftalmar） and Vithas Virgen del Carmen （Qvision） hospitals in Spain.展开更多
The effect of plasma and charged particle interaction with spacecraft in a low Earth orbit(LEO)environment leads to ion focusing and the formation of an ion void in the downstream region as a result of charging.Simula...The effect of plasma and charged particle interaction with spacecraft in a low Earth orbit(LEO)environment leads to ion focusing and the formation of an ion void in the downstream region as a result of charging.Simulations and investigations using a fixed potential imposed on the spacecraft showed the nonsignificance of geophysical parameter changes to ion focusing.Variation of the temperature ratio(T_(r))contributed only to local ion focusing and manifested as two-ion streamers dispersed at the upper and lower edges of the spacecraft-the outermost layers of the satellite structure at the top and bottom,respectively.A simulation involving changing the ambient plasma density(N_(p))also showed the formation of local ion focusing,in which ions were more concentrated as the density increased.Furthermore,auroral electron density(N_(ae))variation had no clear impact on ion focusing,as indicated by static two-ion structures in the wake field.However,variation of the object potential(ϕ)strongly affected ion focusing formation,leading to distortion of the initial ion void region behind the spacecraft.The formation of ion focusing in this study was subject to the electric field produced by the object potential and the ambipolar electric field resulting from plasma expansion in the downstream region.展开更多
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
AIM:To compare the clinical outcomes of extended depth-of-focus intraocular lenses(EDOF IOLs)using either micromonovision implantation or mixed implantation of EDOF and diffractive bifocal IOLs.METHODS:This retrospect...AIM:To compare the clinical outcomes of extended depth-of-focus intraocular lenses(EDOF IOLs)using either micromonovision implantation or mixed implantation of EDOF and diffractive bifocal IOLs.METHODS:This retrospective clinical trial included 130 patients(260 eyes),who were divided into two groups.Group RR comprised 70 patients(140 eyes)bilaterally implanted with ZXR00 IOLs(Tecnis ZXR00,where one target was-0.5 D to-0.75 D and the other was 0 to-0.25 D).Group RM comprised 60 patients(120 eyes)unilaterally implanted with both ZXR00 and ZMB00 IOLs(Tecnis ZMB00,0 to-0.25 D).Postoperative outcomes were compared after 3 mo,including visual acuity,defocus curves,stereoacuity,modulation transfer functions(MTFs),higher-order aberrations,and Visual Function-14(VF-14)questionnaire responses.RESULTS:Group RR had superior bilateral intermediate vision,while the group RM had superior bilateral near vision(both P<0.05).Group RM also exhibited superior MTFs and reduced higher-order aberrations(both P<0.05).Stereoacuity and VF-14 questionnaire results showed no statistically significant difference between groups(P>0.05).CONCLUSION:The implantation of micromonovision has significantly improved near vision.IOLs and their collocation can be customized according to individual patient needs to achieve precise treatment and provide cataract patients with high-quality vision.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
基金Supported by Sichuan Province Science and Technology Plan(No.2023YFS0506)Medical Research Project of Jinniu District,Chengdu,Sichuan Province(No.JNKY2024-94)Xinglin Scholar Program at Chengdu University of Traditional Chinese Medicine(No.ZYTS2023028).
文摘AIM:To evaluate the effects of microlens design of peripheral defocus modifying spectacle lenses(PDMSLs)and non-microlens design of PDMSLs on controlling myopia progression in children and adolescents.METHODS:A systematic search was carried out in the PubMed,Cochrane Library,Embase,CNKI,and Web of Science databases.The search targeted randomized controlled trials(RCTs)and cohort studies(CTs)that explored the effects of PDMSLs on myopia control among children and adolescents.The Cochrane risk-of-bias tool and the Newcastle-Ottawa Scale were employed to evaluate the risk of bias in the included studies.The published biases of the included studies were evaluated using Egger’s test.RESULTS:Nine studies(7 RCTs,2 CTs)were included,involving 4332 participants in the PDMSLs group and 7317 participants in the single vision lenses(SVLs)group.Metaanalysis showed that PDMSLs with microlens design had lower change in spherical equivalent refraction(SER)than SVLs at 6,12,18,and 24mo after wearing glasses,with reductions of 0.19 D(95%CI:0.14 to 0.24,P<0.00001),0.36 D(95%CI:0.25 to 0.46,P<0.00001),0.43 D(95%CI:0.32 to 0.55,P<0.00001),and 0.51 D(95%CI:0.33 to 0.69,P<0.00001),respectively.The changes in axial length(AL)were also lower in PDMSLs compared to SVLs,with reductions of-0.09 mm(95%CI:-0.13 to-0.04,P=0.0002),-0.15 mm(95%CI:-0.21 to-0.08,P<0.00001),-0.27 mm(95%CI:-0.34 to-0.20,P<0.00001),and-0.29 mm(95%CI:-0.38 to-0.20,P<0.00001),respectively.There was no significant difference between the non-microlens group and SVLs in controlling the changes of SER and AL in myopia(both P>0.05).CONCLUSION:The synthesized evidence indicates superior myopia management outcomes with microlens design of PDMSLs compared to both SVLs and nonmicrolens design of PDMSLs in children and adolescents.
文摘AIM:To investigate the expressions of type I collagen, α2 integrin and β1 integrin in the posterior sclera of guinea pigs with defocus myopia and whether basic fibroblast growth factor (bFGF) injection inhibits the formation and development of myopia by upregulating the expression of type I collagen, α2 integrin and β1 integrin. METHODS:After 14 days of treatment, the refractive state and axial length were measured and the levels of type I collagen, α2 integrin and β1 integrin were assayed in the posterior sclerae of groups of guinea pigs that wore a monocular-7D polymethylmethacrylate (PMMA) lens or had -7D lens wear followed by the peribulbar injection of Phosphate Buffer Solution (PBS) or bFGF. The untreated fellow eye served as a control. Guinea pigs with no treatment served as normal group. ·RESULTS:The results showed that 14 days of monocular defocus increased axial eye length and refraction, while bFGF delivery inhibited them markedly. Further, it was also found that the monocular-7D lens could decrease the levels of type I collagen, α2 integrin and β1 integrin expressions, while, unlike PBS, bFGF increased them significantly in comparison to contralateral control eyes and normal eyes. CONCLUSION:bFGF can prevent the formation anddevelopment of defocus myopia by upregulating the expressions of type I collagen, α2 integrin and β1 integrin. Taken together, our results demonstrate that bFGF promotes sclera remodeling to prevent myopia in guinea pigs.
基金The National Natural Science Foundation of China (No 30570485)
文摘The degraded parameters recognition is very important for the restoration of blurred images. There are two common types of blurs for most camera systems. One is the defocus blur due to the optical system's defocus phenomenon and the other is the motion blur due to the relative movement between the objectives and the camera. Compared with the recognition for the blurred image with only one blur model, the parameter estimation for the picture combining defocus and motion blur models is a more complicated mission. A method was proposed for computer to estimate the parameters of defocus blur and motion blur in cepstrum area simultaneously. According to characters of both blur models in the frequency domain, an adjustment approach was suggested in the frequency area and then convert to the cepstrum field to increase the accuracy of measurement.
基金financially supported by the Tianjin Municipal Science and Technology Commission(Grant No.19JCYBJC22000)
文摘An offshore shoal or bar refracts ocean surface waves and causes wave focusing/defocusing on the adjacent beach. Wave focal patterns characterized by alongshore variations in wave height, wave angle, and breaking location induce alongshore non-uniformities of wave setup and nearshore circulation, e.g., rip currents and alongshore currents, in the surfzone. A simplified analytic model for nearshore circulation generated by focused/defocused waves on a planar beach is developed and theoretical solutions are obtained using transport stream function and perturbations in alongshore distributions of wave height and wave angle at the breaker line. The analytic model suggests that alongshore currents are strongly affected by a pair of counter-rotating vortices generated shoreward of the wave focal zone. The vortices are persistent, and their strengths depend on the amplitudes of alongshore variations in wave height and wave angle. The alongshore gradient in wave height tends to intensify the vortices while the convergence of wave angle tends to weaken the vortices. Divergent flows associated with the vortices in the surfzone are intense, strengthening alongshore currents in the downstream of the wave focal zone and weakening alongshore currents or causing flows reversal in the upstream. Alongshore currents are modulated by rip currents associated with the wave focusing/defocusing patterns.
基金Supported by National Natural Science Foundation of China(No.81960177)Jiangxi Provincial Science and Technology Grant(No.20192BAB205049)+2 种基金A research grant from Jiangxi Provincial Health Commission(No.202210723)Postgraduate Innovation Special Fund Project of Jiangxi Province(No.YC2021-S077)。
文摘AIM: To evaluate the effectiveness of peripheral defocus spectacle lenses(PDLs) in myopia control. METHODS: Literature retrieval on Pub Med, Cochrane Library, Embase, and Web of Science databases, and the search time limit was from the establishment of each database to December 29, 2021 were conducted. Change of spherical equivalent refraction(SER) and axial change(AL) were extracted from the literatures that met the inclusion criteria, and Rev Man5.3 software was used for Meta-analysis. RESULTS: A total of 4 randomized controlled trials(RCTs) were included in this Meta-analysis, involving 770 myopic children. The results showed that PDLs could delay the progression of myopia in children with myopia compared with single vision spectacle lenses(SVLs;WMD=0.21 D, 95%CI: 0.01, 0.41, P=0.04). However, there was no significant difference in controlling the growth of axial length(AL) in myopic children(WMD=-0.10 mm, 95%CI:-0.21, 0.01, P=0.07). The results of the effectiveness of myopia control between the two spectacle lenses showed that PDLs were more effective in controlling the progression of myopia(OR=5.73, 95%CI: 2.58, 12.70, P<0.001) and delaying the growth of AL(OR=44.25, 95%CI: 8.84, 221.58, P<0.001) than SVLs, and the differences were statistically significant. CONCLUSION: PDLs can control the progression of myopia compared with SVLs, but cannot delay the growth of AL, and the effectiveness of PDLs in myopia control better than SVLs.
基金Supported by National Natural Science Foundation of China(Grant No.61903268)Jiangsu Provincial Natural Science Foundation of China(Grant No.BK20190823)China Postdoctoral Science Foundation Grant(Grant No.2019M661921).
文摘Three-beam laser internal coaxial wire feeding cladding is regarded as a promising additive manufacturing technique because it is highly efficient and controllable.In this study,the effects of the defocus distance on cladding using a three-beam laser with internal wire feeding are experimentally and numerically studied.A process map indicating the surface characteristics at different defocus distances with various parameter combinations was developed.The transmission characteristics including laser intensity,beam size,and laser spot distance of the three-beam laser at different defocus distances were analyzed using TracePro software.Based on the TracePro results as heat source,a three-dimensional transient finite element(FE)thermal model was formulated to predict the thermal field,temperature history and molten pool shape at different defocus distances.A molten pool with a flat bottom and low melting depth is generated when the defocus distance is−2.5 mm,whereas when this distance is−1.5 mm,a pool with a valley-shaped bond and high melting depth is formed.The simulated results of the temperature cycle and clad geometry are both validated and found to well agree with experimental measurements.The influence of the defocus distance on the microstructure and microhardness are discussed based on the temperature history and cooling rate.With the increase in the absolute defocus distance,the height and dilution of the clad decreased,whereas the width increased.In addition,the effects of defocus distance with various parameter combinations on clad geometry were explored using the formulated FE model.
基金the Deputyship for Research and Innovation,Ministry of Education in Saudi Arabia for funding this research work through the project(No.IFKSUOR3-433-1)。
文摘AIM:To investigate the impact of multifocal gas permeable contact lens(MFGPCL)in various add power and distance/near area allocation on short-term changes of choroidal thickness(ChT),axial length(AL),and retinal defocus profile in young adults.METHODS:Seventeen young adults(2 males and 15 females;age 23.17±4.48y)were randomly assigned to wear two designs binocularly with a one-week washout period in between.Total of four MFGPCL designs were assessed.All designs were distance-center that varied in two add power(+1.50 and 3.00 D)and/or two distance zone(DZ)diameters(1.50 and 3.00 mm;design A:DZ 1.5/add 3.0,B:DZ 1.5/add 1.5,C:DZ 3.0/add 3.0,D:DZ 3.0/add 1.5).ChT,AL,and peripheral refraction data were collected on each subject at baseline,on days 1 and 7 of MFGPCL daily wear.ChT was assessed in four quadrants using a spectraldomain optical coherence tomography.RESULTS:AL was shortened by-26±44μm with lens C,-18±27μm with lens D,-13±29μm with lens A,and-8±30μm with lens B(all P<0.05).A significant overall increase in ChT was observed with all 4 designs(lens A:+6±6μm,B:+3±7μm,C:+8±7μm,and D:+8±7μm).Temporal and superior choroid exhibited more choroidal thickening associated with MFGPCL.All designs induced significant relative peripheral myopia(RPM)beyond the central 20o across the horizontal meridian in both nasal and temporal fields(P<0.05).CONCLUSION:MFGPCLs show a significant influence on ChT and AL,which are associated with significant increase in RPM after short-term wear.The reliability and feasibility of quantifying short-term changes in ChT support its use as a promising marker for the long-term efficacy of myopia-controlling treatments.
基金supported by the National Natural Science Foundation of China (61971165, 61922027, 61773295)in part by the Fundamental Research Funds for the Central Universities (FRFCU5710050119)+1 种基金the Natural Science Foundation of Heilongjiang Province(YQ2020F004)the Chinese Association for Artificial Intelligence(CAAI)-Huawei Mind Spore Open Fund
文摘Reducing the defocus blur that arises from the finite aperture size and short exposure time is an essential problem in computational photography.It is very challenging because the blur kernel is spatially varying and difficult to estimate by traditional methods.Due to its great breakthrough in low-level tasks,convolutional neural networks(CNNs)have been introdu-ced to the defocus deblurring problem and achieved significant progress.However,previous methods apply the same learned kernel for different regions of the defocus blurred images,thus it is difficult to handle nonuniform blurred images.To this end,this study designs a novel blur-aware multi-branch network(Ba-MBNet),in which different regions are treated differentially.In particular,we estimate the blur amounts of different regions by the internal geometric constraint of the dual-pixel(DP)data,which measures the defocus disparity between the left and right views.Based on the assumption that different image regions with different blur amounts have different deblurring difficulties,we leverage different networks with different capacities to treat different image regions.Moreover,we introduce a meta-learning defocus mask generation algorithm to assign each pixel to a proper branch.In this way,we can expect to maintain the information of the clear regions well while recovering the missing details of the blurred regions.Both quantitative and qualitative experiments demonstrate that our BaMBNet outperforms the state-of-the-art(SOTA)methods.For the dual-pixel defocus deblurring(DPD)-blur dataset,the proposed BaMBNet achieves 1.20 dB gain over the previous SOTA method in term of peak signal-to-noise ratio(PSNR)and reduces learnable parameters by 85%.The details of the code and dataset are available at https://github.com/junjun-jiang/BaMBNet.
基金This work is supported by the BK-21 FOUR program and by the Creative Challenge Research Program(2021R1I1A1A01052521)through National Research Foundation of Korea(NRF)under Ministry of Education,Korea.
文摘Enormousmethods have been proposed for the detection and segmentation of blur and non-blur regions of the images.Due to the limited available information about blur type,scenario and the level of blurriness,detection and segmentation is a challenging task.Hence,the performance of the blur measure operator is an essential factor and needs improvement to attain perfection.In this paper,we propose an effective blur measure based on local binary pattern(LBP)with adaptive threshold for blur detection.The sharpness metric developed based on LBP used a fixed threshold irrespective of the type and level of blur,that may not be suitable for images with variations in imaging conditions,blur amount and type.Contrarily,the proposed measure uses an adaptive threshold for each input image based on the image and blur properties to generate improved sharpness metric.The adaptive threshold is computed based on the model learned through support vector machine(SVM).The performance of the proposed method is evaluated using two different datasets and is compared with five state-of-the-art methods.Comparative analysis reveals that the proposed method performs significantly better qualitatively and quantitatively against all of the compared methods.
基金the National Natural Science Foundation of China(No.30570485)
文摘Successful restoration of blurred images depends primarily on the knowledge about the degradationparameter.Defocus blur model in the frequency domain is characterized by concentric rings and the blurradius of the point spread function(PSF)can be identified conveniently in the frequency field for peopleby manual means rather than for computer.This paper introduces a practical method for computer to esti-mate the defocus blur parameter in cepstrum area.Fourier transform plays an intermediate role in the pathto cepstrum domain.We suggest a weighted adjustment operation in the frequency domain and then con-vert it to the cepstrum field to increase the accuracy of recognition.
文摘I am Dr. David P Pifiero from the Department of Optics, Pharmacology and Anatomy of the University of Alicante and from the Department of Ophthalmology of Vithas Medimar （Oftalmar） and Vithas Virgen del Carmen （Qvision） hospitals in Spain.
文摘The effect of plasma and charged particle interaction with spacecraft in a low Earth orbit(LEO)environment leads to ion focusing and the formation of an ion void in the downstream region as a result of charging.Simulations and investigations using a fixed potential imposed on the spacecraft showed the nonsignificance of geophysical parameter changes to ion focusing.Variation of the temperature ratio(T_(r))contributed only to local ion focusing and manifested as two-ion streamers dispersed at the upper and lower edges of the spacecraft-the outermost layers of the satellite structure at the top and bottom,respectively.A simulation involving changing the ambient plasma density(N_(p))also showed the formation of local ion focusing,in which ions were more concentrated as the density increased.Furthermore,auroral electron density(N_(ae))variation had no clear impact on ion focusing,as indicated by static two-ion structures in the wake field.However,variation of the object potential(ϕ)strongly affected ion focusing formation,leading to distortion of the initial ion void region behind the spacecraft.The formation of ion focusing in this study was subject to the electric field produced by the object potential and the ambipolar electric field resulting from plasma expansion in the downstream region.
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.
文摘AIM:To compare the clinical outcomes of extended depth-of-focus intraocular lenses(EDOF IOLs)using either micromonovision implantation or mixed implantation of EDOF and diffractive bifocal IOLs.METHODS:This retrospective clinical trial included 130 patients(260 eyes),who were divided into two groups.Group RR comprised 70 patients(140 eyes)bilaterally implanted with ZXR00 IOLs(Tecnis ZXR00,where one target was-0.5 D to-0.75 D and the other was 0 to-0.25 D).Group RM comprised 60 patients(120 eyes)unilaterally implanted with both ZXR00 and ZMB00 IOLs(Tecnis ZMB00,0 to-0.25 D).Postoperative outcomes were compared after 3 mo,including visual acuity,defocus curves,stereoacuity,modulation transfer functions(MTFs),higher-order aberrations,and Visual Function-14(VF-14)questionnaire responses.RESULTS:Group RR had superior bilateral intermediate vision,while the group RM had superior bilateral near vision(both P<0.05).Group RM also exhibited superior MTFs and reduced higher-order aberrations(both P<0.05).Stereoacuity and VF-14 questionnaire results showed no statistically significant difference between groups(P>0.05).CONCLUSION:The implantation of micromonovision has significantly improved near vision.IOLs and their collocation can be customized according to individual patient needs to achieve precise treatment and provide cataract patients with high-quality vision.
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.
