Ring-shaped Pattern Research Articles

The role of single cell mechanical behavior and polarity in driving collective cell migration.

The directed migration of cell collectives is essential in various physiological processes, such as epiboly, intestinal epithelial turnover, and convergent extension during morphogenesis as well as during pathological events like wound healing and cancer metastasis. Collective cell migration leads to the emergence of coordinated movements over multiple cells. Our current understanding emphasizes that these movements are mainly driven by large-scale transmission of signals through adherens junctions. In this study, we show that collective movements of epithelial cells can be triggered by polarity signals at the single cell level through the establishment of coordinated lamellipodial protrusions. We designed a minimalistic model system to generate one-dimensional epithelial trains confined in ring shaped patterns that recapitulate rotational movements observed in vitro in cellular monolayers and in vivo in genitalia or follicular cell rotation. Using our system, we demonstrated that cells follow coordinated rotational movements after the establishment of directed Rac1-dependent polarity over the entire monolayer. Our experimental and numerical approaches show that the maintenance of coordinated migration requires the acquisition of a front-back polarity within each single cell but does not require the maintenance of cell-cell junctions. Taken together, these unexpected findings demonstrate that collective cell dynamics in closed environments as observed in multiple in vitro and in vivo situations can arise from single cell behavior through a sustained memory of cell polarity.

Robust excitation and Raman conversion of guided vortices in a chiral gas-filled photonic crystal fiber.

The unique ring-shaped intensity patterns and helical phase fronts of optical vortices make them useful in many applications. Here we report for the first time, to the best of our knowledge, efficient Raman frequency conversion between vortex modes in a twisted hydrogen-filled single-ring hollow core photonic crystal fiber (SR-PCF). High-fidelity transmission of optical vortices in an untwisted SR-PCF becomes more and more difficult as the orbital angular momentum (OAM) order increases, due to scattering at structural imperfections in the fiber microstructure. In a helically twisted SR-PCF, however, the degeneracy between left- and right-handed versions of the same mode is lifted, with the result that they are topologically protected from such scattering. With launch efficiencies of ${\sim}{75}\% $∼75%, a high damage threshold and broadband guidance, these fibers are ideal for performing nonlinear experiments that require the polarization state and azimuthal order of the interacting modes to be preserved over long distances. Vortex coherence waves of internal molecular motion carrying angular momentum are excited in the gas, permitting the polarization and OAM of the Raman bands to be tailored, even in spectral regions where conventional solid-core waveguides are opaque or susceptible to optical damage.

Regional Ecological Risk Assessment of Wetlands in the Sanjiang Plain with Respect to Human Disturbance

Characterization of the intensity of regional human disturbances on wetlands is an important scientific issue. In this study, the pole-axis system (involving multi-level central places and roads) was recognized as a proxy of direct risk to wetlands stemming from human activities at the regional or watershed scale. In this respect, the pole-axis system and central place theory were adopted to analyze the spatial agglomeration characteristics of regional human activities. Soil erosion and non-point source (NPS) pollution, indicating the indirect effect of human activities on wetlands, were also considered. Based on these human disturbance proxies, which are considered regional risk sources to wetlands, incorporated with another two indicators of regional environment, i.e., vulnerability and ecological capital indexes, the regional ecological risk assessment (RERA) framework of wetlands was finally established. Using this wetland RERA framework, the spatial heterogeneity of risk grades within the Naoli River Basin, a typical concentrated wetland region in the Sanjiang Plain, was analyzed. The results showed that (1) high- and very high-risk source intensity areas displayed a ring-shape distribution pattern, which reflected the influence of the regional pole-axis system; (2) owing to their high ecological capital value per unit area and vulnerability level, the wetlands had the highest risk grade, as did central places (i.e., those areas where county seats and administration bureaus of farms were located). In terms of proportion, the low-, medium-, high-, and very high-risk areas accounted for 72.0%, 16.8%, 10.1%, and 1.1% of the study area, respectively. The identification and classification of risk sources to wetlands that are related to human activity at the watershed scale could provide clear perspectives in order to reduce severe risk sources to these areas, especially those Ramsor Convention-appointed sites of international importance. Moreover, the assessment framework used in this paper will provide a helpful reference for related research in the future. Finally, the new management guidelines proposed in this paper will be beneficial for lowering the ecological risk level of wetlands at the watershed or regional scale for the Sanjiang Plain or other wetland-concentrated regions.

Irradiation-Induced Segregation at Dislocation Loops in CoCrFeMnNi High Entropy Alloy

To understand the redistribution of alloying element in high entropy alloys (HEAs) under irradiation, a CoCrFeMnNi alloy was irradiated with 1 MeV Kr ions at room temperature and 500oC, and characterized with atom probe tomography (APT) and transmission electron microscopy. At 500oC, Co and Ni were enriched at interstitial dislocation loops resulted from the ion irradiation. In contrast, no segregation was observed at interstitial dislocation loops formed at room temperature. It is inferred that the inverse Kirkendall effect through vacancy flux, as opposed to interstitial binding, was the primary mechanism attributing to the observed segregation. In addition, APT concentration contour plots show a ring-shaped segregation pattern instead of a disk-shaped pattern at the faulted dislocation loops, indicating the non-equilibrium nature of the defect clustering and solute segregation process of the CoCrFeMnNi under irradiation at high temperature.

Ultra-intense laser pulse characterization using ponderomotive electron scattering

We present a new analytical solution for the equation of motion of relativistic electrons in the focus of a high-intensity laser pulse. We approximate the electron’s transverse dynamics in the averaged field of a long laser pulse focused to a Gaussian transverse profile. The resultant ponderomotive scattering is found to feature an upper boundary of the electrons’ scattering angles, depending on the laser parameters and the electrons’ initial state of motion. In particular, we demonstrate the angles into which the electrons are scattered by the laser scale as a simple relation of their initial energy to the laser’s amplitude. We find two regimes to be distinguished in which either the laser’s focusing or peak power are the main drivers of ponderomotive scattering. Based on this result, we demonstrate how the intensity of a laser pulse can be determined from a ring-shaped pattern in the spatial distribution of a high-energy electron beam scattered from the laser. We confirm our analysis by means of detailed relativistic test particle simulations of the electrons’ averaged ponderomotive dynamics in the full electromagnetic fields of the focused laser pulse.

Turing patterns on a plasma-liquid interface

Radially symmetric patterns are observed in pin-to-plane DC plasma systems where a liquid solution is used as a planar resistive anode. The size and structure of these patterns depends on the plasma current and salt concentration of the liquid anode. We propose that these patterns initiate due to the reaction and diffusion of electrons in the anode sheath, where electron impact ionization serves as an autocatalytic reaction. The resulting system of reaction-diffusion equations is amenable to Turing stability analysis, which we use to theoretically predict the transition from a uniform plasma to a ring-shaped pattern state. Expressing the stability criteria in terms of plasma current and solution salt concentration, we derive a theoretical phase boundary for the onset of pattern formation, which is in excellent agreement with experimental results.

Biosynthesis of silver, gold and silver–gold alloy nanoparticles using Persea americana fruit peel aqueous extract for their biomedical properties

While several green biomolecules have been used to synthesize functional and biologically compatible nanoparticles, little attention has been paid to Persea americana (PA) (avocado) fruit extract as a potential reducing agent. This study used avocado fruit peel aqueous extracts to synthesize silver nanoparticles (PAAgNPs), gold nanoparticles (PAAuNPs) and bimetallic alloy nanoparticles (PAAg–AuNPs). The particles were characterized using UV–vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy, selected area electron diffraction (SAED), energy-dispersive X-ray spectroscopy and X-ray diffraction among others. The particles were assessed for their antibacterial, antifungal and antioxidant properties. The UV–vis spectroscopy showed PAgNPs, PAAuNPs and PAAg–AuNPs with surface plasmon resonance at 455.5, 538 and 540.5 nm, respectively. The significant FTIR peaks: PAAgNPs (3358 cm−1), PAAuNPs (3503 cm−1) and PAAg–AuNPs (3651 cm−1) pointed to protein as both capping and stabilizing agents for the synthesized nanoparticles. Generally, the particles were spherical, with size range of 18–80 nm for PAAgNPs, 16–71 nm for PAAuNPs and 44–55 nm for PAAg–AuNPs. The energy-dispersive X-ray spectra showed silver, gold and silver/gold as conspicuous metals in PAAgNPs, PAAuNPs and PAAg–AuNPs colloids, respectively. SAED showed ring-shaped patterns for the particles. The nanoparticles effectively inhibited growth of tested bacteria (11–94%) for PAAgNPs, (10–77%) for PAAuNPs and (20–85%) for PAAg–AuNPs. The effectiveness of the biosynthesized nanoparticles can be placed as PAAg–AuNPs > PAAgNPs > PAAuNPs. The fungal inhibition performances are 33–76%, 50–82% and 27–88% for PAAgNPs, PAAuNPs and PAAg–AuNPs, respectively, while DPPH-scavenging activities were 57.82–63.25%, 15.28–54.50% and 53.05–54.26%, which were dose dependent at the tested concentrations of 20–100 µg/ml with good antioxidant activities compared to standard BHA (41.46–84.57%) and ascorbic acid (43.56–91.10%). The bleaching inhibition assay of ABTS showed activities of 56.15–85.43% (PAAgNPs), 34.67–50.93% (PAAuNPs) and 45.31–94.01% (PAAg–AuNPs). The lower concentrations of EC50 were obtained in nanoparticles (24.45–58.33 µg/ml) compared with the standards (38.42–69.04 µg/ml), indicating that the nanoparticles could suffice as good agents in drug consignment. This study has demonstrated the potential of P. americana fruit peel aqueous extracts to synthesize AgNPs, AuNPs and Ag–AuNPs for antimicrobial and antioxidant applications. The current work, to the best of our knowledge, is the first to use avocado peel extract to synthesis nanoparticles.

Visualization of the halo region in plant–powdery mildew interactions by cryoscanning electron microscopy

Halos are circular or ring-shaped cell wall appositions surrounding pathogen entry sites on host leaves. The diameter of halos on infected Blumeria graminis wheat leaves varied between 10 and 100 μm, which reflected specificity of local host plant responses. Using cryoscanning electron microscopy (cryoSEM) without metal sputtering we observed halos as light circles or ring-shaped patterns on the leaves of cereals infected with B. graminis, and on the leaves of several dicotyledonous plants infected with specialized powdery mildews. Hydrogen peroxide treatment of wheat leaves increased the number of cryoSEM detected halos. They were more distinct than in the control without treatment and showed better contrast with surrounding epidermis. The presented cryoSEM method allows simultaneous monitoring of halos and fungal structures and, possibly, visualizes penetration sites with elevated production of reactive oxygen species.

Multivariate weighted recurrent network for analyzing SSMVEP signals from EEG literate and illiterate

Recently, the Steady-State Motion Visual Evoked Potential (SSMVEP)-based Brain Computer Interface (BCI) has attracted a lot of attention. We design a SSMVEP-based BCI, in which a ring-shaped motion checkerboard pattern is used to realize SSMVEP stimulation. In particular, we firstly conduct SSMVEP experiments to obtain electroencephalogram (EEG) signals from 10 subjects, including 5 EEG literates and 5 EEG illiterates. By using the Canonical Correlation Analysis (CCA) and Support Vector Machine (SVM) method, we find that the classification accuracies of EEG illiterates are relatively lower than that of EEG literates. Thus, in order to investigate the differences in brain cognitive processes between the two groups of subjects, we construct a multivariate weighted recurrence network and analyze the weighted local efficiency and the clustering coefficient of the two groups. The results indicate that in SSMVEP experiment, there are significant differences between the two groups of subjects in these two network indicators. Our approach and analysis provide novel insights into the cognitive behavior of the brain and understanding of the “BCI Illiteracy” problem.

Roles of Inner and Outer Fringe and Asymmetric Coupling Effect in Concentric Double-MIS(p) Tunneling Diodes

It has been known that the saturated current of MIS(p) tunnel diode (TD) is periphery-dependent because of magnifying of fringing-field effect [1]. Furthermore, due to its high sensitivity to the change of minority carriers from surroundings, MIS(p) shows noticeable results towards light or bias-added neighboring gate in a concentric structure [2]. Nonetheless, it is lack of discussion on the amount of coupling contribution from the inner and outer fringe of the outer ring-shaped MIS TD. In this work, two sets of ring-shaped and concentric MIS TD patterns are designed. The first set is made with the outer fringe ROo fixed and inner fringe ROi varying, and the second set is designed contrarily. The schematics of the top view, cross section and parameter table of ring-shaped and concentric double-MIS TD are shown in Fig. 1 (a) and (b), respectively. The radius of inner and outer fringe of the outer ring are named as ROi and ROo. Besides, “Vring” denotes the bias of the ring-shaped MIS TD in Fig. 1 (a) and the notation of “VI” and “VO” represent bias of inner and outer electrodes in the concentric MIS TD in Fig. 1 (b).The distinct difference lies in the saturated light current part of Fig. 2 where the result of set 1 (Fig. 2 (a)) merge perfectly while that of set 2 (Fig. 2 (b)) do not. We further divide the currents in Fig. 2 (a) with their area (JA,ring) and obtain merged currents in the accumulation region in Fig. 3 (a), indicating they are uniform TDs with same oxide thickness. Then, we divide Fig. 2 (a) with their respective total perimeter (JP,ring) and find the saturated dark currents merged better now in Fig. 3 (b). This can be attributed to the similar perimeter-dependent phenomenon as in single MIS TD case [1]. Combining the results above, it is inferred that both of the inner and outer fringes contribute to saturation current of a ring-shaped MIS TD at dark. However, with light added the dominant term in saturated current becomes that amount of charges grabbed by the outer fringe through a diverging field so that the light current shows great consistency for devices with same ROo.In the following analysis, we examine the concentric double-MIS TD structure with a 30μm gap from two operating situations. One is the case where the inner circle functions as the gate and the outer ring plays as the sensor [i.e., inner gate outer sensor (IGOS)]. In the opposite case, the inner circle serves as sensor while the outer ring works as the control gate [i.e., inner sensor outer gate (ISOG)]. It is found in our recent work [3] that the extent of the coupling effect between the inner device and the outer ring is unequal (shown in the inset of Fig. 4). By utilizing this asymmetric coupling effect, a higher sensitivity can be achieved at a lower voltage bias, therefore become more power-efficient in IGOS. Fig. 4 (a) and (b) show the I-V curves of sample A in IGOS and ISOG operations. It is observed that in the IGOS situation, the light currents under different VIG are nearly fixed. This can be interpreted as a combined result of asymmetric coupling effect and the above-mentioned inference that the main role in grabbing carriers under illumination is the outer fringe of the ring. Also, similar results are found among samples with 6 different outer ring-to-inner circle area ratios ranging from 48 to 4. Contrarily, in the ISOG situation, the extent of light current influenced by outer control bias will be relatively larger owing to the strongly besieging field.Finally, Fig. 5 shows the I-V curves of the concentric MIS TD with ROo fixed and the total power consumption of (a) IGOS and (b) ISOG operations under a control bias of 1.0V. It is noted that as the outer ring-to-inner circle area ratio increases (from ratio of C : 0.9 to A : 8), the light-to-dark current ratio rises while total power consumption becomes lower and therefore more efficient. It is concluded that the roles of inner and outer fringe are different and the coupling effect is of importance to high-density devices. This work is supported by the Ministry of Science and Technology of Taiwan, ROC, under Contract No. MOST 105-2221-E-002-180-MY3 and MOST 107-2622-8-002-018.[1] Y. K. Lin and J. G. Hwu, IEEE TED, 61, 9, 2014[2] W. T. Hou and J. G. Hwu, ECSJ, 6, 10, 2017 [3] Y. H. Chen and J. G. Hwu, IEEE TED, 65, 11, 2018 Figure 1

Roles of Inner and Outer Fringe and Asymmetric Coupling Effect in Concentric Double-MIS(p) Tunneling Diodes

During the studies of coupling effects between the outer ring and inner circle in a concentric structure of double-metal-insulator-semiconductor tunnel diode, we have proposed an asymmetric coupling effect to account for the distinctive difference between two opposite operations. However, further investigation is needed to make our mechanism more robust. In this work, we designed two sets of ring-shaped and concentric MIS tunnel diode lithographic patterns with a fixed inner fringe in the first set and a fixed outer fringe in the second set. From both the experimental and TCAD-simulated results, we have found that the major role in grabbing charges is the outer fringe of a ring-shaped MIS structure and that this outer fringe-dominated characteristic accompanied with the asymmetric coupling effect results in the observable difference in two contrary operation modes where the inner circle and outer ring take turns to play as the control gate.

FLUORESCENCE LIFETIME PATTERNS IN MACULAR TELANGIECTASIA TYPE 2.

Type 2 idiopathic macular telangiectasia (MacTel) is a rare bilateral neurodegenerative disease characterized by alterations in the macular capillary network leading to central vision loss. The purpose of this study was to quantify disease-specific retinal fluorescence lifetime patterns in patients with MacTel using fluorescence lifetime imaging ophthalmoscopy. Both eyes of 14 patients (mean age ± SEM, 67.8±6.4 years) with a clinical diagnosis of MacTel Type 2 and 14 healthy age-matched controls (age 69.8±6.4 years) were included in this study. All participants were imaged with a fluorescence lifetime imaging ophthalmoscope (Heidelberg Engineering, Germany). Mean retinal fluorescence lifetimes (Tm) were obtained in the short spectral channels (498-560 nm) and long spectral channels (560-720 nm). Clinical features, fundus images, fundus autofluorescence intensity images, spectral domain optical coherence tomography, and corresponding macular pigment optical density measurements using a modified confocal scanning laser ophthalmoscope (mpHRA) were further analyzed. Patients were classified into five phenotypic subgroups using the Gass and Blodi classification. Mean fluorescence lifetimes were significantly prolonged temporal to the fovea in patients with MacTel compared with healthy controls (mean ± SEM: short spectral channels 543 ± 61 ps vs. 304 ± 9 ps; P < 0.0001; long spectral channels: 447 ± 26 ps vs. 348 ± 11 ps; P < 0.0001), and appeared as a crescent or ring-shaped pattern. Prolonged lifetime patterns correlated with decreased macular pigment density on macular pigment optical density measurements. Follow-up examinations were performed in four MacTel patients, which revealed an increase of short spectral channel Tm of 22% over 2.1 years in the temporal fovea. This study confirms that fundus autofluorescence lifetimes display characteristic patterns in patients with MacTel Type 2 disease and provide information about macular pigment and possibly photoreceptor loss. Fluorescence lifetime prolongation correlates with disease severity and may therefore be a useful addition to other imaging modalities for assessing disease progression in MacTel Type 2.

Manipulation of a ring-shaped beam via spatial self- and cross-phase modulation at lower intensity.

We report a tunable ring-shaped diffraction pattern via either nonlinear spatial self- or cross-phase modulation caused by the EIT-like effect in rubidium atomic vapor. During the propagation of an input Gaussian-profile beam, its output wavefront exhibits a ring-shaped diffraction pattern. Furthermore, the spot center can be tuned from dark to bright by varying individual experimental parameters, such as power, frequency detuning, the polarization state of the incident beams and atomic temperature, which makes the nonlinear phase shift evolve beyond 2π. In particular, the input intensity can be as low as 500 W m-2.

Enhanced NO Gas Performance of (002)-Oriented Zinc Oxide Nanostructure Thin Films

(002)-oriented ZnO nanostructure for NO gas sensing application was successfully grown on glass substrates by two-step processes, which are seeding process via dip-coating method using diethanolamine (DEA) as chelating agent and growth process via chemical bath deposition (CBD). The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Two ZnO film samples, named samples A and B, were fabricated without and with DEA addition in the seeding process, respectively. XRD observation results show that ZnO film was successfully deposited on both samples, where sample A has a random crystal orientation; while sample B has a very dominant (002) orientation. Further, the selected area electron diffraction (SAED) observation with TEM confirmed that sample A has a random orientation indicated by a ring-shaped diffraction pattern; while sample B has a hexagonal crystalline structure diffraction pattern which is oriented towards the normal direction of the substrate surface, indicated that ZnO film was grown along this (002) orientation for sample B. SEM images of both samples showed that the ZnO film is ZnO nanorods with hexagonal wurtzite structure shape and sample A is clearly more randomly oriented than sample B. During the investigation of NO gas sensing performance, it is found that the highest response towards NO gas was occurred at a lower operating temperature of 200°C for sample B compared to a higher operating temperature of 300°C for sample A. Furthermore, sample B has a higher dynamic gas response and sensitivity than sample A. These results indicate that the (002) oriented ZnO film has a better performance than the randomly oriented ZnO film as NO gas sensor.

Evolutionary melting pots and reproductive isolation: A ring-shaped diversification of an odorous frog (Odorrana margaratea) around the Sichuan Basin.

Quaternary climatic oscillations and geography are of primary importance in shaping intraspecific genetic diversity. We examined the diversification patterns and inferred processes for the green odorous frog (Odorrana margaretae) of western China. Species distribution modelling showed that the species has a continuous circular distribution around the Sichuan Basin while the basin itself is largely uninhabitable. Population genetic and phylogenetic analyses revealed that the species has a ring-shaped divergent pattern. While the chain of populations around the Basin maintains a mostly gradual and continuous genetic variation, populations between the north and west showed little gene exchange. Two processes, glacial refugial history and geography, likely contributed to the observed patterns. Our genetic clustering analysis revealed two clusters, suggesting two refugial groups among the populations, one from the west and the other from the east. Postglacial expansion may have created two contact zones. One at the south had extensive population admixture and produced a gradual transition between the western and eastern populations. Consequently, this region has the highest genetic diversity and represents an evolutionary "melting pot." In contrast, the second contact zone at the northwestern side of the Basin has limited admixture, suggesting partial reproductive isolation between the northern and western populations. Furthermore, an isolation-by-distance analysis revealed a strong correlation (Mantel r=0.745) between the genetic and geographic distances, when we assumed that populations were connected following the circular distribution without gene flow across the NW contact zone. We also explored alternative explanations, such as a one-refugium scenario. With its micro-ring, the green odorous frog is poised to make an excellent model system for understanding the process of speciation.

Characterization of Retinitis Pigmentosa Using Fluorescence Lifetime Imaging Ophthalmoscopy (FLIO).

PurposeWe investigated fundus autofluorescence (FAF) lifetimes in patients with retinitis pigmentosa (RP) using fluorescence lifetime imaging ophthalmoscopy (FLIO).MethodsA total of 33 patients (mean age, 40.0 ± 17.0 years) with RP and an age-matched healthy group were included. The Heidelberg FLIO was used to detect FAF decays in short (SSC; 498–560 nm) and long (LSC; 560–720 nm) spectral channels. We investigated a 30° retinal field and calculated the amplitude-weighted mean fluorescence lifetime (τm). Additionally, macular pigment measurements, macular optical coherence tomography (OCT) scans, fundus photographs, visual fields, and fluorescein angiograms were recorded. Genetic studies were performed on nearly all patients.ResultsIn RP, FLIO shows a typical pattern of prolonged τm in atrophic regions in the outer macula (SSC, 419 ± 195 ps; LSC, 401 ± 111 ps). Within the relatively preserved retina in the macular region, ring-shaped patterns were found, most distinctive in patients with autosomal dominant RP inheritance. Mean FAF lifetimes were shortened in rings in the LSC. Central areas remained relatively unaffected.ConclusionsFLIO uniquely presents a distinct and specific signature in eyes affected with RP. The ring patterns show variations that indicate genetically determined pathologic processes. Shortening of FAF lifetimes in the LSC may indicate disease progression, as was previously demonstrated for Stargardt disease. Therefore, FLIO might be able to indicate disease progression in RP as well.Translational RelevanceHyperfluorescent FLIO rings with short FAF lifetimes may provide insight into the pathophysiologic disease status of RP-affected retinas potentially providing a more detailed assessment of disease progression.

Patterns of Fundus Autofluorescence Lifetimes In Eyes of Individuals With Nonexudative Age-Related Macular Degeneration.

PurposeTo investigate fundus autofluorescence (FAF) lifetimes in patients with nonexudative AMD.MethodsA total of 150 eyes of 110 patients (mean age: 73.2 ± 10.7 years) with nonexudative AMD, as well as a healthy group of 57 eyes in 38 subjects (mean age: 66.5 ± 8.7 years), were included. Investigations were conducted at the University Eye Clinic in Jena, Germany, as well as the Moran Eye Center in Salt Lake City, Utah, USA, using the Heidelberg Engineering Spectralis-based fluorescence lifetime imaging ophthalmoscope (FLIO). A 30° retinal field centered at the fovea was investigated. FAF decays were detected in short (498–560 nm) and long (560–720 nm, LSC) spectral channels. The mean fluorescence lifetimes (τm) were calculated. Optical coherence tomography scans and fundus photographs were also recorded.ResultsIn patients with nonexudative AMD, FLIO shows a ring-shaped pattern of prolonged τm in the LSC. This pattern occurs in all patients with AMD (including very early stages) and in one-third of the healthy controls. FAF lifetimes were longer with more advanced stages. The presence of drusen is associated with prolonged τm when compared with the healthy fundus, but drusen identification is difficult with FLIO only.ConclusionsFLIO detects a clear pattern of changes within the fundus, which appears to be AMD-associated. These changes are already visible in early AMD stages and not masked by the presence of other coexisting retinal diseases. These findings may be useful for the early diagnosis of AMD and to distinguish AMD from other retinal diseases.

Highly Interactive Brain\u2013Computer Interface Based on Flicker-Free Steady-State Motion Visual Evoked Potential

Visual evoked potential-based brain–computer interfaces (BCIs) have been widely investigated because of their easy system configuration and high information transfer rate (ITR). However, the uncomfortable flicker or brightness modulation of existing methods restricts the practical interactivity of BCI applications. In our study, a flicker-free steady-state motion visual evoked potential (FF-SSMVEP)-based BCI was proposed. Ring-shaped motion checkerboard patterns with oscillating expansion and contraction motions were presented by a high-refresh-rate display for visual stimuli, and the brightness of the stimuli was kept constant. Compared with SSVEPs, few harmonic responses were elicited by FF-SSMVEPs, and the frequency energy of SSMVEPs was concentrative. These FF-SSMVEPs evoked “single fundamental peak” responses after signal processing without harmonic and subharmonic peaks. More stimulation frequencies could thus be selected to elicit more responding fundamental peaks without overlap with harmonic peaks. A 40-target online SSMVEP-based BCI system was achieved that provided an ITR up to 1.52 bits per second (91.2 bits/min), and user training was not required to use this system. This study also demonstrated that the FF-SSMVEP-based BCI system has low contrast and low visual fatigue, offering a better alternative to conventional SSVEP-based BCIs.

Characterization of dough baked via blue laser

Depth of heat penetration and temperature must be precisely controlled to optimize nutritional value, appearance, and taste of food products. These objectives can be achieved with the use of a high-resolution blue diode laser—which operates at 445 nm—by adjusting the water content of the dough and the exposure pattern of the laser. Using our laser, we successfully cooked a 1 mm thick dough sample with a 5 mm diameter ring-shaped cooking pattern, 120 repetitions, 4000 mm min−1 speed, and 2 W laser power. Heat penetration in dough products with a blue laser is significantly higher compared to with an infrared laser. The use of a blue laser coupled with an infrared laser yields most optimal cooking conditions for food layered manufacture.

Fabrication of hexagonal star-shaped and ring-shaped patterns arrays by Mie resonance sphere-lens-lithography

Mie resonance sphere-lens-lithography has proved to be a good candidate for fabrication of large-area tunable surface nanopattern arrays. Different patterns on photoresist surface are obtained theoretically by adjusting optical coupling among neighboring spheres with different gap sizes. The effect of light reflection from the substrate on the pattern produced on the photoresist with a thin thickness is also discussed. Sub-micron hexagonal star-shaped and ring-shaped patterns arrays are achieved with close-packed spheres arrays and spheres arrays with big gaps, respectively. Changing of star-shaped vertices is induced by different polarization of illumination. Experimental results agree well with the simulation. By using smaller resonance spheres, sub-400 nm star-shaped and ring-shaped patterns can be realized. These tunable patterns are different from results of previous reports and have enriched pattern morphology fabricated by sphere-lens-lithography, which can find application in biosensor and optic devices.