Stripe Pattern Research Articles

Biological evaluation of microcurrent wound dressing based on printed silver and zinc electrodes

Five types of silver/zinc (Ag/Zn) microcurrent dressings with different metal content were fabricated by screen printing and well-characterized by morphology, electricity and biological analysis in this study. Ag and Zn were printed alternately in a stripe pattern on the dressings’ surface. The metal particles adhered to the dressings sparsely, then densely, as the metal content increased gradually. The electrical test showed that with the increase of the metal content on the dressings, the current and voltage between positive and negative electrodes increased correspondingly. Hemolysis experiments demonstrated that the low to medium concentration of the metal would not cause hemolysis of red blood cells and had excellent blood compatibility. The results of coagulation experiments indicated that the coagulation performance within 10 min of the dressings was comparable with that of alginate dressing; in addition, the hemostatic performance was excellent. The cytotoxicity tests showed that the dressing A-C with low to medium concentration of the metal content, had no cytotoxicity, which followed the dose–effect relationship between the cytotoxicity and the metal content of the dressing. Furthermore, cell migration and mitochondrial membrane potential experiments indicated that microcurrent dressings altered mitochondrial membrane potentials of human foreskin fibroblast (HFF) cells while regulating cell migration. The stronger the current generated by the microcurrent base cloth, the more pronounced the migration effect of HFF cells becomes, and the higher the membrane potential of the fibroblasts within the acceptable threshold value range.

Functional conservation and divergence of color-pattern-related agouti family genes in teleost fishes.

While color patterns are highly diverse across the animal kingdom, certain patterns such as countershading and stripe patterns have evolved repeatedly. Across vertebrates, agouti-signaling genes have been associated with the evolution of both patterns. Here we study the functional conservation and divergence by investigating the expression patterns of the two color-pattern-related agouti-signaling genes, agouti-signaling protein 1 (asip1) and agouti-signaling protein 2b (asip2b, also known as agrp2) in Teleostei. We show that the dorsoventral expression profile of asip1 and the role of the "stripe repressor" asip2b are shared across multiple teleost lineages and uncover a previously unknown association between stripe-interstripe patterning and both asip1 and asip2b expression. In some species, including the zebrafish (Danio rerio), these two genes show complementary and overlapping expression patterns in line with functional redundancy. Our results thus suggest how conserved and novel functions of agouti-signaling genes might have shaped the evolution of color patterns across teleost fishes.

Spatiotemporal dynamics for a diffusive mussel\u2013algae model near a Hopf bifurcation point

In this paper, the Hopf bifurcation and Turing instability for a mussel–algae model are investigated. Through analysis of the corresponding kinetic system, the existence and stability conditions of the equilibrium and the type of Hopf bifurcation are studied. Via the center manifold and Hopf bifurcation theorem, sufficient conditions for Turing instability in equilibrium and limit cycles are obtained, respectively. In addition, we find that the strip patterns are mainly induced by Turing instability in equilibrium and spot patterns are mainly induced by Turing instability in limit cycles by numerical simulations. These provide a comprehension on the complex pattern formation of a mussel–algae system.

Dynamic regulation of anterior-posterior patterning genes in living Drosophila embryos

Expression of the gap and pair-rule genes plays an essential role in body segmentation during Drosophila embryogenesis.1-5 However, it remains unclear how precise expression patterns of these key developmental genes arise from stochastic transcriptional activation at the single-cell level. Here, I employed genome-editing and live-imaging approaches to comprehensively visualize regulation of the gap and pair-rule genes at the endogenous loci. Quantitative image analysis revealed that the total duration of active transcription (transcription period) is a major determinant of spatial patterning of gene expression in early embryos. The length of the transcription period is determined by the continuity of bursting activities in individual nuclei, with the core expression domain producing more bursts than boundary regions. Each gene exhibits a distinct rate of nascent RNA production during transcriptional bursting, which contributes to gene-to-gene variability in the total output. I also provide evidence for "enhancer interference," wherein a distal weak enhancer interferes with transcriptional activation by a strong proximal enhancer to downregulate the length of the transcription period without changing the transcription rate. Analysis of the endogenous hunchback (hb) locus revealed that the removal of the distal shadow enhancer induces strong ectopic transcriptional activation, which suppresses refinement of the initial broad expression domain into narrower stripe patterns at the anterior part of embryos. This study provides key insights into the link between transcriptional bursting, enhancer-promoter interaction, and spatiotemporal patterning of gene expression during animal development.

Near-infrared fundus camera with a patterned interference filter for the retinal scattering detection

The fundus camera is a system that enables retinal observations for the diagnosis of eye diseases. A near-infrared (NIR) multispectral fundus imaging system can capture color images using NIR light instead of visible light, thus avoiding irritation of the eyes and allowing for easier observations of the fundus. In this study, we developed an NIR fundus camera with a patterned metal mask for retinal patterned illumination. The pattern illuminated fundus images from the experiment prove the feasibility of retinal scattering detection using retinal patterned illumination. The layout of the patterned mask was optimized to prevent the interaction of scattered light and the multi-layer film structures of a patterned interference filter were proposed. The simulated transmission spectra showed that the transmittance of the linear stripe pattern, visual target, and fundus illumination are sufficiently high for the retinal patterned illumination.

COMPLEX FRACTIONAL-ORDER HIV DIFFUSION MODEL BASED ON AMPLITUDE EQUATIONS WITH TURING PATTERNS AND TURING INSTABILITY

A weakly nonlinear analysis provides a system constituting amplitude equations and its related analysis is capable of predicting parameter regimes with different patterns expected to co-exist in dynamical circumstances that exhibit complex fractional-order system characteristics. The Turing mechanism of pattern formation as a result of diffusion-induced instability of the homogeneous steady state is concerned with unpredictable conditions. The Turing instability caused by fractional diffusion in a Human Immunodeficiency Virus model has been addressed in this study. It is important that the effect of the Human Immunodeficiency Virus to the immune system can be modeled by the interaction of uninfected cells, unhealthy cells, virus particles and antigen-specific. Initially, all potential equilibrium points are defined and the stability of the interior equilibrium point is then evaluated using the Routh–Hurwitz criteria. The conditions for Turing instability are obtained by local equilibrium points with stability analysis. In the neighborhood of the Turing bifurcation point, weakly nonlinear analysis is employed to deduce the amplitude equations. After applying amplitude equations, it is observed that this system has a very rich dynamical behavior. The constraints for the formation of the patterns like a hexagon, spot, mixed and stripe patterns are identified for the amplitude equations by dynamic analysis. Furthermore, by using the numerical simulations, the theoretical results are verified. Within this framework, this study through the dynamical behavior of the complex system perspective and bifurcation point based on the viral death rate can provide the basis for several researchers working on Human Immunodeficiency Virus model through various aspects. Accordingly, the Turing bifurcation point and weakly nonlinear analysis employed within the complex fractional-order dynamics addressed herein are highly relevant experimentally since the related effects can be studied and applied concerning different mathematical, physical, engineering and biological models.

Characteristics and controlling factors of alpine grassland vegetation patch patterns on the central Qinghai-Tibetan plateau

Vegetation patch patterns, which are used as indicators of state, functionality, and catastrophic changes in the arid ecosystem, have received much attention. However, little is known about the controlling factors and indicators that underlie vegetation patch patterns in the alpine grassland ecosystem. Here, we firstly studied characteristics of vegetation patch patterns with aerial photography by using an unmanned aerial vehicle and evaluated the vegetation patch-size distribution with power law (PL) and truncated power law (TPL) models on the central part of the Qinghai-Tibetan Plateau (QTP). We then investigated the effects of environmental factors and biotic disturbances on vegetation patch patterns. The results showed that (1) there were four typical vegetation patch patterns, i.e. spot, stripe, sheet, and uniform patterns; (2) soil water content and air temperature were major environmental factors affecting vegetation patch patterns; (3) biotic disturbance of plateau pika (Ochotona curzoniae) affected vegetation patch patterns by changing the number, area, and connectivity of vegetation patches; and (4) vegetation patch-size distribution parameters were significantly related to soil hydrothermal variables (P < 0.01). We concluded that the development of alpine vegetation patch patterns was controlled by soil hydrothermal conditions and plateau pika’s disturbance. We also proposed that γ (TPL-PL) (difference between absolute values of slopes of TPL and PL curve fits) could serve as an effective indicator for monitoring alpine grassland conditions, and preventing patchiness was a critical task for the alpine ecosystem management and restoration.

Automatic individual non-invasive photo-identification of fish (Sumatra barb Puntigrus tetrazona) using visible patterns on a body

Non-invasive fish identification of individuals can provide new possibilities for the monitoring of fish cultivation, improve and make fish production technologies less demanding for farmers, and increase fish welfare. The aim of this research is to confirm the idea of automatic non-invasive image-based fish identification of individuals using visible features on a fish body and prove the pattern stability during the fish cultivation period. Visible patterns, such as black stripes along the body of a Sumatra barb (Puntigrus tetrazona), were used for machine identification of individual fish. Two experiments were completed: a short-term experiment (43 fish) to show the uniqueness of the stripe patterns for identification, and a long-term experiment (25 fish) to test the stability of patterns during the cultivation period. The overall accuracy of classification was 100% for data collection in one day and 88% between two data collection times. This study shows that visible patterns and image processing methods can be used to automatically identify individual fish of the same species. This is not just limited to Sumatra barb—the concept should work for any fish with unique visible skin patterns, for example, for commercial fish species like Atlantic salmon (Salmo salar) and European perch (Perca fluviatilis).

Complex Dynamics of a Ratio-Dependent Predator-Prey Model Induced by Spatial Motion

One of the most efficient predator-prey models with spatial effects is the one with ratio-dependent functional response. However, there is a need to further explore the effects of spatial motion on the dynamic behavior of population. In this work, we study a ratio-dependent predator-prey model with diffusion terms. The aim of this work is to investigate the changes in predator’s distribution in space as the prey populations change their mobility. We observe that the frequency diffusion of the prey gives rise to the sparse density of the predator. Moreover, we also observe that the increasing rate of the conversion into predator biomass induces pattern transitions of the predator. Specifically speaking, Turing pattern of the predator populations goes gradually from a spotted pattern to a black-eye pattern, with the intermediate state being the mixture of spot and stripe pattern. The simulation results and analysis of this work illustrate that the diffusion rate and the real intrinsic factor influence the persistence of the predator-prey system mutually.

Adherent cell remodeling on micropatterns is modulated by Piezo1 channels

Adherent cells utilize local environmental cues to make decisions on their growth and movement. We have previously shown that HEK293 cells grown on the fibronectin stripe patterns were elongated. Here we show that Piezo1 function is involved in cell spreading. Piezo1 expressing HEK cells plated on fibronectin stripes elongated, while a knockout of Piezo1 eliminated elongation. Inhibiting Piezo1 conductance using GsMTx4 or Gd3+ blocked cell spreading, but the cells grew thin tail-like extensions along the patterns. Images of GFP-tagged Piezo1 showed plaques of Piezo1 moving to the extrusion edges, co-localized with focal adhesions. Surprisingly, in non-spreading cells Piezo1 was located primarily on the nuclear envelope. Inhibiting the Rho-ROCK pathway also reversibly inhibited cell extension indicating that myosin contractility is involved. The growth of thin extrusion tails did not occur in Piezo1 knockout cells suggesting that Piezo1 may have functions besides acting as a cation channel.

Two-dimensional localized states in an active phase-field-crystal model.

The active phase-field-crystal (active PFC) model provides a simple microscopic mean field description of crystallization in active systems. It combines the PFC model (or conserved Swift-Hohenberg equation) of colloidal crystallization and aspects of the Toner-Tu theory for self-propelled particles. We employ the active PFC model to study the occurrence of localized and periodic active crystals in two spatial dimensions. Due to the activity, crystalline states can undergo a drift instability and start to travel while keeping their spatial structure. Based on linear stability analyses, time simulations, and numerical continuation of the fully nonlinear states, we present a detailed analysis of the bifurcation structure of resting and traveling states. We explore, for instance, how the slanted homoclinic snaking of steady localized states found for the passive PFC model is modified by activity. Morphological phase diagrams showing the regions of existence of various solution types are presented merging the results from all the analysis tools employed. We also study how activity influences the crystal structure with transitions from hexagons to rhombic and stripe patterns. This in-depth analysis of a simple PFC model for active crystals and swarm formation provides a clear general understanding of the observed multistability and associated hysteresis effects, and identifies thresholds for qualitative changes in behavior.

Diffusion-induced regular and chaotic patterns in a ratio-dependent predator-prey model with fear factor and prey refuge.

Population distribution of interacting species in a large scale natural system is heterogeneous and subject to change for various reasons. Here, we explore how behavioral modification in prey species due to fear of predator and mutual interference between predators can create different spatiotemporal patterns in population distribution. We show that the fear factor and diffusion in a ratio-dependent predator-prey model may show more complex dynamics than observed earlier. It is shown that when prey diffusivity is low, prey remains concentrated at different patches throughout the domain. However, prey density becomes low at the patches as they disperse at a higher rate. Mixed and stripe patterns are observed during the transition from a hot spot pattern at the lower prey diffusivity to a cold spot pattern at its higher value. Pattern transition is, however, completely opposite if the antipredator behavior is gradually increased. Our simulation results reveal that the spatiotemporal chaotic pattern may also be observed in the Hopf-Turing region of instability provided prey shows a higher level of antipredator behavior. The chaotic pattern of the Hopf-Turing region may be shifted to a spot type pattern of the Turing region depending on the refuge level of the habitat.

스트라이프 패턴을 사용한 패션 디자인 이미지 분석 및 활용방안

이 연구의 목적은 스트라이프 패턴을 사용한 패션 디자인의 이미지와 디자인 요소와의 관계를 분석하여 스트라이프 패턴 사용에 따른 특정 이미지의 디자인 전개를 위한 실질적인 아이디어를 제공하는 것이다. 연구방법은 2014년 S/S에서 2018년 S/S까지 패션 컬렉션에 등장한 패션 스타일 중 609점을 대상으로 8개 이미지 범주를 사용하여 패션 이미지를 분석하였고, 통계를 사용하여 디자인의 형태적 요소, 스트라이프의 표현요소, 배색 관계에서 패션 이미지와의 관련성을 도출하였다. 스트라이프 패턴 이 사용된 디자인의 이미지는 로맨틱, 모던, 에스닉, 매니시, 엘레강트, 아방가르드, 스포티, 클래식 순 의 빈도를 보였고, 패션 이미지와 디자인 요소의 연관성 분석, 즉 아이템, 도련 위치, 실루엣, 스트라이프 패턴의 선 방향, 선 모양, 반복 형태, 배색 관계 모두에서 패션 이미지에 따른 유의미한 차이가 발견되었다. 그 결과를 토대로 스트라이프 패턴을 사용한 패션 디자인의 이미지 활용방안을 제시하면 다 음과 같다. 로맨틱 이미지는 허벅지 길이의 X 실루엣 원피스 디자인에 고명도의 무채색과 유채색의 조합으로 이루어진 가로/혼합 방향의 선을 사용, 엘레강트 이미지는 풀렝스 원피스에 명도/채도차를 적게 둔 사선/혼합방향의 선, 클래식 이미지는 수트류에 저명도 중심의 전통적 선염 직물용 세로 방향 스트라이프를 사용, 모던 이미지는 간결한 원피스에 간격의 대비, 명도 차가 뚜렷한 무채색의 규칙적 인 세로 방향 스트라이프 사용, 매니시 이미지는 풀렝스 팬츠 아이템에 규칙적 세로 방향 스트라이프 사용, 스포티 이미지는 탑 & 팬츠/원피스 아이템에 채도차를 강조한 가로 방향 스트라이프 사용, 아방 가르드 이미지는 오벌 실루엣과 착시를 일으키는 불규칙적 반복/혼합 방향의 스트라이프 사용, 에스닉 이미지는 풀렝스 원피스에 가로 방향의 다양한 선들과 탁색조 중심의 멀티배색 등 시각적 복잡성을 강조하는 방향으로 활용하면 패션 이미지의 전달이 더욱 강화될 것으로 제안한다.

One-shot three-dimensional measurement method with the color mapping of light direction

A one-shot three-dimensional measurement method of a material surface with a color mapping imaging system of the light direction extracted BRDF (bidirectional reflectance distribution function) is proposed here. The imaging system can measure light directions reflected from a material surface using a stripe pattern multicolor filter having a translational symmetry in one direction. Assuming that surface inclination angles are sufficiently small and that the surface has a flat peripheral boundary, a reconstruction method of a three-dimensional surface from light directions is derived theoretically on the basis of the geometrical optics. The method is experimentally validated using a round ridge fabricated on an aluminum flat plate.

Swimmers Heal on the Move Following Catastrophic Damage.

Herein, we describe the development of 2D self-healing small-scale swimmers capable of autonomous propulsion and "on-the-fly" structural recovery in large containers. Incorporation of magnetic Nd2Fe14B microparticles in specialized printed strips results in rapid reorientation and reattachment of the moving tail to its complementary broken static piece to restore the original swimmer structure and propulsion behavior. The swimmers display functional recovery independent of user input. Measurements of the magnetic hysteresis and fields were used to assess the behavior of the healing mechanism in real swimming situations. Damage position and multiple magnetic strip patterns have been examined and their influence upon the recovery efficiency has been compared. Owing to its versatility, fast response, and simplicity the new self-healing strategy represents an important step toward the development of new "on-the-fly" repairing strategies for small-scale swimmers and robots.

Visualization of large-scale charged domain Walls in hexagonal manganites

A ferroelectric charged domain wall (CDW) carries bound charges, originating from the variation of the normal components of polarization across the domain boundary, leading to a possible two-dimensional conductive interface in insulating materials. The ferroelectric CDW can be precisely created, erased, and manipulated, therefore offering an intriguing pathway toward the design of nano-devices. However, due to rather large energy costs, the size of the CDW is usually on the nanoscale. Here, taking flux-grown ferroelectric hexagonal manganites (h-RMnO3) as an example, we creatively adopted an accessible inclined polishing process to reveal the domain evolution of stripe, loop, and vortex domain patterns by depth profiling. Interestingly, we observed an unexpected large-scale straight CDW in as-grown LuMnO3 with length up to a millimeter size, which may result from the “polar catastrophe” during the flux growth. The large-scale CDW has a residual influence on the formation of the loop domain when the crystal anneals below the ferroelectric transition temperature, but completely disappears as the topological vortices emerge. The observed large-scale CDWs make h-RMnO3 a potential candidate for advanced electronic devices, leading to a panoply of desired properties.

Dual modal plasmonic substrates based on a convective self-assembly technique for enhancement in SERS and LSPR detection.

In this study, surface-enhanced Raman scattering (SERS) scheme is combined with localized surface plasmon resonance (LSPR) detection on a thin gold film with stripe patterns of gold nanoparticles (GNPs) via convective self-assembly (CSA) method. The potential of dual modal plasmonic substrates was evaluated by binding 4-ABT and IgG analytes, respectively. SERS experiments presented not only a high sensitivity with a detection limit of 4.7 nM and an enhancement factor of 1.34 × 105, but an excellent reproducibility with relative standard deviation of 5.5%. It was found from plasmonic sensing experiments by immobilizing IgG onto GNP-mediated gold film that detection sensitivity was improved by more than 211%, compared with a conventional bare gold film. Our synergistic SERS-LSPR approach based on a simple and cost-effective CSA method could open a route for sensitive, reliable and reproducible dual modal detection to expand the application areas.

Structural transformations of growing thin colloidal crystals in confined space via convective assembly

The structural evolution of growing thin colloidal crystals in a confined space via the convective assembly technique has been investigated. The thin colloidal crystals were grown in a wedge-shaped cell, where the height of the cell increased with increased crystal growth. Triangle and square patterns, denoted as [111]- and [100]-oriented grains, respectively, were formed alternately as the height of the cell increased. The structural transformation was associated with an increase in the number of layers when the n-layer [100]-oriented grains changed to n + 1-layer [111]-oriented grains. Between the different grain structures, a stripe pattern was observed, which was a transitional region, where particle configuration gradually changed. The structural transformation occurred through the continuous change of particle configuration rather than through the abrupt formation of a grain boundary. The interval of the strip pattern lengthened as the number of layers increased, which is understood to be the structure with the highest packing density. The findings of the study give a better insight into convective assembly in a confined space, and also contribute to the greater structural control of colloidal crystals, useful for a number of applications.

A long-term record (1995–2019) of the dynamics of land desertification in the middle reaches of Yarlung Zangbo River basin derived from Landsat data

Widespread desertification in the middle part of the Yarlung Zangbo River (YZR) basin is threatening the sustainable development of this region. To capture this process, a method was proposed for large-scale desertification monitoring by using Landsat images from 1995 to 2019. The method used an integrated classification method combined with a hierarchical decision tree and nearest neighbor classifiers. The spatio-temporal dynamics of the desertification pattern were analyzed to assist in the detection of possible driving forces. Using validation samples collected from Google Earth high-resolution images and field investigations, the overall accuracy of the classification in 2019 was 92.3% with a Kappa coefficient of 0.84. The major results were: (1) total sandy land area in 2019 was 734.1 km2, which accounted for 3.7% of the study area, prominently distributed along the wide river valleys and inlets of tributaries with a strip and discontinuous pattern. Sandy land tends to be distributed in the southern aspect regions with lower elevations and that are closer to rivers; (2) sandy land areas showed two temporal stages: a gradual increase of 102.4 km2 from 1995 to 2015 and a large decrease of 106.8 km2 from 2015 to 2019; (3) newly increased sandy land was distributed in the YZR Valley, while the revegetation on sandy land occurred mainly in the Lhasa River basin and some regions in the YZR Valley; and (4) increased sandy land area of 142.1 km2 was mainly distributed in the southern band of the two rivers. Correspondingly, revegetation on sandy land was more effective on the northern banks of the river valleys. These findings provide guidance for implementing vegetation recovery on sandy lands and provide important insights for maintaining sustainable development.

Investigation of the stripe patterns from X-ray reflection optics.

X-ray beams reflected from a single layer or multilayer coating are widely used for X-ray tomography, holography, and X-ray phase contrast imaging. However, the observed irregular stripe patterns from either unfocused or defocused beams often cause disturbing artifacts and seriously deteriorate the image quality. In this work, we investigate the origin of these irregular fine structures using the wave optics theory. The connection to similar results obtained by the geometric optics theory is also presented. The proposed relation between the second derivative of the wavefront and the irregular structures was then verified by conducting at-wavelength metrology with the speckle-based wavefront sensing technique. This work will not only help to understand the formation of these irregular structures but also provide the basis for manufacturing future 'stripe-free' refection optics.