Myopia induced by flickering light in guinea pigs: a detailed assessment on susceptibility of different frequencies

AIM: To investigate the effectiveness and feasibility of inducing myopia in guinea pigs by flickering light (FL) stimulation with different frequencies. METHODS: Seventy 2 -week-old guinea pigs were randomly assigned to six groups: five FL groups and a control group (n =12 for each). Animals in the five FL groups were raised under 500lx illumination with a duty diurnal cycle of 50% at a flash rate of 5, 1, 0.5, 0.25 and 0.1Hz respectively. Those in the control group were reared under steady 250lx illumination. Refraction, axial length, and radius of curvature were measured before and at 2, 4, 6, 8, 10 and 12 weeks after treatment. At week 12, the eyeballs were taken out and three ocular dimensions and dry weight of sclera were measured. RESULTS: A myopic shift and axial eye length increase developed in the five FL groups. Stimulation at 0.5Hz caused greater changes in myopic shift, axial elongation, eyeball dimension, and dry weight of sclera than stimulation at other frequencies. Compared with controls, eyes in 0.5Hz group were approximately -5.5 ±1.5D more myopic with increase in horizontal, vertical, axial dimensions by 0.89 ±0.3mm, 0.69 ±0.2mm, 1.12 ±0.2mm respectively and with increase in dry weight of sclera by 0.44mg. CONCLUSION: Chronic exposure to periodic illumination at temporal frequency is attended by development of excessive ocular enlargement and myopic refractive error. Emmetropization could bedisrupted differently by frequency alteration.

多频谐和与噪声作用下Flickering振子的安全盆侵蚀与混沌

研究了催化反应Flickering振子在多频率确定性谐和外力和有界随机噪声联合作用下,系统安全盆的侵蚀和混沌现象.将Melnikov方法推广到包含有限多个频率外力和随机噪声联合作用的情形,推导出了系统的随机Melnikov过程,根据Melnikov过程在均方意义上出现简单零点的条件给出了系统出现混沌的临界值,然后用数值模拟方法计算了系统的安全盆分岔点.结果表明,由于随机扰动的影响,系统的安全盆分岔点发生了偏移,并且使得混沌容易发生.同时证明,激励频率数目的增加扩大了参数空间上的混沌区域,也使得安全盆分岔提前发生,系统变得不安全.

Cell Registration and Flickering Detection for the Complexity Analysis of Red Blood Cell Dynamics with GSM Exposure

Red blood cells(RBC)' flickering present the dynamic properties of the cytomembrane. Its complexity could be used for aging analysis or the evaluation for the storage quality. The flickering activity is a kind of reversible perpendicular motion of the specified pixel. Therefore, the complexity analysis depends on the reliable detection of temporal variation for the gray-scale values from each pixel of the cells. In this paper, we improved our previous work on the screening of the horizontal drifted cells with a surface based on cell registration method and the effect of GSM exposure to the dynamic properties of the RBCs in terms of multi-scale sample entropy was presented in the paper.

高分辨率TFT-LCD光电自动校正系统设计

针对当前MIPI接口的高分辨率TFT-LCD(液晶显示屏)光电校正基本是手动校正,或者部分自动校正现状,搭建了适合目前高分辨率液晶显示的ARM+FPGA+双SSD2828光电自动校正系统,实现了GAMMA2.2、Flicker最佳Vcom自动校正算法的优化,改善了影响高分辨率TFT-LCD显示品质的亮度、暗度、对比度、色度、闪烁等光电参数,提升了显示品质。实验结果表明该系统可支持2 K×4 K高分辨率TFT-LCD,刷新率最高可达144 Hz。整体校正时间稳定在30 s,满足厂线快速生产的需要,且校正系统成本低、系统升级方便,在显示技术行业具有较强的应用价值。

Design of Digital Linear Power Supply with Low Current Ripple

A linear power supply is a circuit architecture directly driven by AC. Multiple high-voltage LEDs (light-emitting diodes) are connected in series to withstand the input voltage. The LEDs are divided into multiple segments through a segment switching mechanism to adapt to the pulsating DC changes after bridge rectification. Due to imperfect switching between control signals, there may be signal overlap or misalignment, which reduces circuit performance and component lifespan. Firstly, signal overlap occurs when the next segment opens before the previous segment is about to close. This state causes overlapping intervals where two segments of current combine, resulting in a high combined current that can lead to significant power losses and generate heat, potentially reducing the lifespan of the components. Secondly, signal misalignment occurs when the next segment prepares to open after the previous segment has completely closed. In this state, there is a time gap with no current flow, resulting in reduced output power and exacerbating LED flickering. Both of these undesirable phenomena introduce ripple into the LED output current. In this paper, a digitalized design is proposed to precisely compensate for the timing between alternating signals, significantly reducing output current ripple. This approach helps enhance power supply performance, extend component lifespan, and reduce LED index flicker.

Non-Local Theory of Bose-Einstein Condensate and Stopping of Light

The problem of an adequate description of the transport processes in Bose-Einstein condensates (CBE), including space-temporal evolution of CBE in a gravitational field is considered. The full nonlocal system for the CBE evolution is delivered including particular case and analytical solutions. We show (analytically) that a black hole can evolve in the Bose-Einstein condensate (CBE) regime. At the same time, there are modes in which black hole flickering occurs. Quantization of the black holes flickering is discovered. The corresponding nonlocal hydrodynamic equations indicated for fermions gas.

光照对ADS模式TFT-LCD Flicker漂移的影响

在挠曲电效应的基础上,研究了光照对ADS模式TFT-LCD Flicker漂移的影响。首先研究了正常点灯下Flicker漂移情况,然后测试了不加背光和降低背光亮度下的Flicker漂移,最后研究了光照panel一段时间后Flicker漂移情况。实验结果表明,光照使Cell盒内产生了离子,驱动信号电压存在时液晶发生极化,产生的"力"吸附离子,从而形成了直流偏压,产生了Flicker漂移。降低光照强度Flicker漂移程度减弱。利用该结果在一定程度上对显示器整体设计和品质的改善有重要指导意义。

Critical flicker frequency for diagnosis and assessment of recovery from minimal hepatic encephalopathy in patients with cirrhosis

BACKGROUND:Minimal hepatic encephalopathy (MHE) impairs quality of life and predicts overt hepatic encephalopathy (HE) in cirrhotic patients.Diagnosis of MHE requires cumbersome tests.Lactulose is effective in the treatment of MHE.This study aimed to evaluate the use of critical flicker frequency (CFF) for the diagnosis of MHE in cirrhotic patients after treatment.METHODS:One hundred and ten patients were evaluated by psychometry (number connection tests A,B or figure connection tests A,B),P300 auditory event related potential (P300ERP),venous ammonia,and CFF for MHE.MHE was diagnosed by abnormal psychometry (>2SD age matched controls) and P300ERP.MHE patients were treated with lactulose for one month.Response was defined by normalization (<2SD of matched controls) of both psychometry and P300ERP.RESULTS:Of the 110 patients [Child Turcott Pugh score A:B:C 39:42:29,(age 41.6±11.6 years,M:F 82:28)],75 (68%) had abnormal results of psychometric tests,and 74 (67%) had prolonged P300ERP.Fifteen (20%) patients with abnormal results of psychometric tests had normal P300ERP.Thus sixty (54.5%) patients were diagnosed as having MHE.After treatment for one month,34 (57%) recovered while 26 (43%) continued to have abnormal resents of psychometric or P300ERP tests.CFF was <39 Hz in 72 (65.4%) patients before treatment and in 20 (33.3%) after treatment.CFF sensitivity,specificity,positive predictive value,negative predictive value,and diagnostic accuracy for the assessment of recovery of MHE were 65%,91%,85%,77% and 80%,respectively.CONCLUSION:CFF is a simple,relatively reliable,and accurate test without any dependence on age or literacy in the diagnosis and assessment of recovery of patients with MHE.

它灯将是最佳看 ? 白炽，荧光灯或带等等

Low frequency flicker,high frequency flicker,strong light,strong blue light,infrared,ultraviolet,electromagnetic radiation,ripple flicker and dimming flicker produced by different lamps have negative impact on vision,eyes and health. Negative impact on eyes resulting in myopia or cataract etc: the solution is to remove all the negative factors by applying upright lighting technology and that is optimum to vision,eyes and health.

TFT-LCD屏的Flicker和DC残留的研究及改善

由于平面电场的非对称设计和挠曲电效应的存在,导致正负帧作用下透过率不同,目视有很明显的闪烁。本文在396 mm(15.6 in)FHD(1 920×1 080)竖双畴结构的基础上,通过LCD expert软件模拟平面电场显示模式正负帧作用下电压-穿透率(Voltage-Transmittance,V-T)曲线,同时,实测了像素电极(pixel-ITO)不同线宽线距产品的残留DC(Direct Current)值/Flrcker数值等,得出较好的实验条件,对今后的像素设计有一定的指导意义。

A User-Friendly SSVEP-Based BCI Using Imperceptible Phase-Coded Flickers at 60Hz

A brain-computer interface(BCI)system based on steady-state visual evoked potentials(SSVEP)was developed by four-class phase-coded stimuli.SSVEPs elicited by flickers at 60Hz,which is higher than the critical fusion frequency(CFF),were compared with those at 15Hz and 30Hz.SSVEP components in electroencephalogram(EEG)were detected using task related component analysis(TRCA)method.Offline analysis with 17 subjects indicated that the highest information transfer rate(ITR)was 29.80±4.65bpm with 0.5s data length for 60Hz and the classification accuracy was 70.07±4.15%.The online BCI system reached an averaged classification accuracy of 87.75±3.50%at 60Hz with 4s,resulting in an ITR of 16.73±1.63bpm.In particular,the maximum ITR for a subject was 80bpm with 0.5s at 60Hz.Although the BCI performance of 60Hz was lower than that of 15Hz and 30Hz,the results of the behavioral test indicated that,with no perception of flicker,the BCI system with 60Hz was more comfortable to use than 15Hz and 30Hz.Correlation analysis revealed that SSVEP with higher signal-to-noise ratio(SNR)corresponded to better classification performance and the improvement in comfortableness was accompanied by a decrease in performance.This study demonstrates the feasibility and potential of a user-friendly SSVEP-based BCI using imperceptible flickers.

LED Flicker: A Drawback or an Opportunity?

In this paper we examine the flicker of commercial LED lamps and with the help of volunteers we explore the parameter space (frequency and duty cycle) in order to find pulsing operating conditions under which the light fluctuations are not visually perceived. The results show that LEDs under mains voltage manifest the most extreme cases of flicker and we also confirm that under pulsing mode the overall impression is of higher brightness which is an opportunity for energy savings. The results also show that the background color and luminance contrast is of high importance. Finally we propose an easy method for consumers to detect flickering of light sources under mains voltage.

FLICKER INDEX METHOD FOR EVALUATING FLICKER IN COLOR PDPs

Objective In order to red uc e the flicker in color plasma display panel (PDP), the highly peaked light outpu t at certain positions and the strong luminance difference among subfields, whic h cause flicker in PDP, is analyzed; and a flicker index method is developed to evaluate flicker in PDP based on the flicker theory and the electroencephalograp h response model for luminance. Methods This method considers f licker as a main result of the fundamental frequency component of luminance supe rimposed on the DC-component, the flicker index is defined as ratio between the positive square roots of the sum of the two square components. Results & Conclusion The calculation results of flicker index indicate that flicker can be obviously weakened via increase of subfield number, symmetrical s election and homogeneous interlaced distribution of major weight subfields . Fli cker can be further reduced by choosing the suitable subfield order according to gray scale region of image.

Flicker defined form and RareBit measurements lack in specificity of visual pathways

AIM:To evaluate the different visual pathways represented by the Heidelberg Engineering Perimeter flicker defined form and RareBit(magnocellular and parvocellular respectively)in different age-groups and according to the fatigue.METHODS:Totally 64 eyes of 32 healthy subjects were included in the prospective study.Each participant underwent screening—ophthalmic examination including best-corrected visual acuity,anterior and posterior segment assessment,and visual field examination with Heidelberg Edge Perimetry(HEP)-standard automated perimeter(SAP)24-2.They were observed for 2 y previously to the enrollment.This helped to define that the enrolled patients did not bear the glaucoma-developing potential.During the screening and after two years the HEP had been conducted in the standard protocol 24-2 and RareBit perimetry(RBP)in accordance with the manufacturer’s description.Participants were randomly assigned to the groups:flicker defined form(FDF)-first or RBP-first.This defined from which additional visual field test the participant started.Participants were additionally subdivided to younger and older study groups.The effect of subject variables was explored with Mann-Whitney U-test.Testing for the presence of correlations between parameters was performed using the Spearman Rank Order Correlations and confirmed by the parametric tests.For the influence of additional factors,the Kruskal-Wallis test was performed.RESULTS:The positive correlation between meandeviation(MD)and mean hit rate(MHR)and pattern standard deviation(PSD)and standard deviation of MHR(±MHR)were found in younger study group(P=0.005,r=0.481 and P=0.0074,r=0.465),whereas in the older subgroup no correlation was observed.Additionally,the randomization protocol helped in defining the role of fatigue on the HEP-FDF results.Participant for whom the HEPFDF was performed after RareBit had significantly worse results than those for whom the HEP-FDF was first.In the younger group,the MHR and±MHR depend from age in that group(P<0.05,r=0.43 and r=-0.57 respectively)while no age-dependent differences were found in HEPrelated parameters.On the contrary in the older group the MD and PSD varies with age(P<0.05,r=0.47 and r=-0.44 respectively)while the RBP parameters remained unchanged.The questionnaire showed that participants preferred RareBit over HEP-FDF in terms of a duration time,comfort,understanding of the test procedures,and ocular pain(P<0.05).CONCLUSION:The influence of patient’s fatigue should be considered during HEP-FDF examination.An overlap hypothesis should be reevaluated after determining of other factors that affect HEP-FDF and RareBit results.

Novel computerized psychometric tests as primary screening tools for the diagnosis of minimal hepatic encephalopathy

Minimal hepatic encephalopathy(MHE)is a critical neurocognitive complication of decompensated liver cirrhosis and portosystemic shunting,which results in a wide range of cognitive deficits including impairments in working attention,psychomotor speed,and executive function.Current guidelines have recommended paper-and-pencil psychometric tests for the diagnosis of MHE.Most high-risk cirrhotic patients are required to be examined;however,paperand-pencil psychometric tests are neither convenient nor rapid to perform in the clinic.Recently,novel computerized psychometric tests,including the inhibitory control test,EncephalApp Stroop App,and critical flicker frequency,have been proven to be rapid,effective,and convenient methods for screening MHE in clinical practice and for identifying high-risk cirrhotic patients for further validation using rigid neuropsychometric examinations.However,diagnostic accuracy of these tests is influenced by educational background,age,and cultural differences.This review summarizes clinical evidence of the application of novel computerized psychometric tests for screening MHE.

Quantitative Evaluation of Flicker ERG Waveforms in Low Vision Patients

Flicker electroretinograms(FERGs)of 30Hz were recorded for 46eyes(23 cases)of low vision,including 38 eyes with retinal diseases and 8eyes with optic neuropathy,and for 39 normal eyes(33 cases).The recordedwave forms were analysed by two methods:(1)to measure the peak to peakamplitude and pseudophase directly,and(2)to measure the amplitude andphase of fundamental response component(30Hz)by discrete Fourier trans-form(DFT).The abnormality ratios between these two methods were com-pared in low vision pati...

Experimental Demonstration of <i>g_m</i>/I<i>_D</i>Based Noise Analysis

Recent studies using BSIM3 models have suggested that noise depends on the transconductance-to-drain ratio gm/ID of a transistor. However, to the best of our knowledge, no experimental result demonstrating gm/ID dependent noise previously observed in simulation is available in the literature. This paper examines the underlying principles that make it possible to analyze noise using gm/ID based noise analysis. Qualitative discussion of normalized noise is presented along with experimental results from a 130 nm CMOS process. A close examination of the experimental results reveals that the device noise is width independent from 1 Hz to 10 kHz. Moreover, noise increases as gm/ID is reduced. The experiment observation that noise is width independent makes it possible for circuit designers to generate normalized parameters that are used to study noise intuitively and accurately.

Psychophysics in the ophthalmological practice—Ⅱ.Contrast sensitivity

Contrast is the differential luminance between one object and another.Contrast sensitivity(CS)quantifies the ability to detect this difference:estimating contrast threshold provides information about the quality of vision and helps diagnose and monitor eye diseases.High contrast visual acuity assessment is traditionally performed in the eye care practice,whereas the estimate of the discrimination of low contrast targets,an important complementary task for the perception of details,is far less employed.An example is driving when the contrast between vehicles,obstacles,pedestrians,and the background is reduced by fog.Many conditions can selectively degrade CS,while visual acuity remains intact.In addition to spatial CS,“temporal”CS is defined as the ability to discriminate luminance differences in the temporal domain,i.e.,to discriminate information that reaches the visual cortex as a function of time.Likewise,temporal sensitivity of the visual system can be investigated in terms of critical fusion frequency(CFF),an indicator of the integrity of the magnocellular system that is responsible for the perception of transient stimulations.As a matter of fact,temporal resolution can be abnormal in neuro-ophthalmological clinical conditions.This paper aims at considering CS and its application to the clinical practice.

Wind Energy Conversion System from Electrical Perspective—A Survey

This paper focuses on the wind energy conversion system (WECS) with the three main electrical aspects: 1) wind turbine generators (WTGs), 2) power electronics converters (PECs) and 3) grid-connection issues. The current state of wind turbine generators are discussed and compared in some criteria along with the trends in the current WECS market, which are ‘Variable Speed’, ‘Multi-MW’ and ‘Offshore’. In addition, the other crucial component in the WECS, PECs will be discussed with its topologies available in the current WECS market along with their modulation strategies. Moreover, three main issues of the WECS associating with the grid-connection, fault-ride through (FRT) capability, harmonics/interharmonics emission and flicker, which are the power quality issues, will be discussed due to the increasing responsibility of WECS as utility power station. Some key findings from the review such as the attractiveness of BDFRG are presented in the conclusion of this paper.

一种解决CMOS图像传感器工频闪烁的方法

CMOS图像传感器在安防设备,医疗设备,军用设备和航空设备中被广泛使用,这些CMOS图像传感器大部分都是采用滚动式的逐行曝光方式。在大部分使用环境中,会出现交流电供电的照明灯具,这样就会出现工频闪烁干扰(Flicker),要对工频干扰进行处理需要先实现对干扰光源的供电频率(50Hz/60Hz)进行检测,本文重点讲述利用图像处理技术实现交流电频率检测的方法,从而解决了工频干扰的问题。