Fish Eye Research Articles

Design and Micro-Fabrication of Focused High-Frequency Needle Transducers for Medical Imaging.

In this study, we report an advanced fabrication technique to develop a miniature focused needle transducer. Two different types of high-frequency (100 MHz) transducers were fabricated using the lead magnesium niobate-lead titanate (PMN-0.3PT) and lithium niobate (LiNbO3) single crystals. In order to enhance the transducer’s performance, a unique mass–spring matching layer technique was adopted, in which gold and parylene play the roles of the mass layer and spring layer, respectively. The PMN-0.3PT transducer had a 103 MHz center frequency with a −6 dB bandwidth of 52%, and a signal-to-noise ratio (SNR) of 42 dB. The center frequency, −6 dB bandwidth, and SNR of the LiNbO3 transducer were 105 MHz, 66%, and 44 dB, respectively. In order to compare and evaluate the transducers’ performances, an ultrasonic biomicroscopy (UBM) imaging on the fish eye was performed. The results showed that the LiNbO3 transducer had a better contrast resolution compared to the PMN-0.3PT transducer. The fabricated transducer showed an excellent performance with high-resolution corneal epithelium imaging of the experimental fish eye. These interesting findings are useful for the future biomedical implementation of the fabricated transducers in the field of high-resolution ultrasound imaging and diagnosis purpose.

Yolov4-tiny with wing convolution layer for detecting fish body part

Detection of a fish's eye, tail and body is the initial process in the vision system for determining the freshness and species of fish, as well as calculating the number of fish automatically in the fishing industry. Classification performance of a system is affected by its ability to detect the intact body of a fish or its body parts. The You Only Look Once version 4 tiny (Yolov4-tiny) is a lightweight object detector that can detect body parts of a fish with fairly good detection accuracy. However, massive siltation of convolution layer in the Yolov4-tiny backbone leads to low feature diversity. This research proposes a modification of the Yolov4-tiny architecture to improve detection accuracy by enhancing and balancing feature diversity and attaching an extra-branch detector to detect small-sized objects. In addition, we propose the use of bottleneck and expansion convolution to reduce computational resources usage. Our contributions are enhancing feature diversity using a wing convolution layer (WCL), balancing feature diversity using tiny spatial pyramid pooling (Tiny-SPP), reducing computational resources of feature pyramid network (FPN) connections using bottleneck and expansion convolution (BEC), and detecting small objects using an extra-branch as a third-scale detector. Our experimental results show that the proposed model outperforms the original model and other modified Yolov4-tiny models with Precision, Recall, AP, and mAP of 97.48%, 93.3%, 94.07%, and 92.38% respectively. The proposed model is smaller in size and more efficient in the use of computing resources.

Universal Hall conductivity in graphene Maxwell fish-eye quantum dot

Graphene quantum dot with Maxwell fish eye potential energy profile is studied. A quasiclassical approximation is used given that potential energy is a slowly varying function of coordinates. Near the zero energy the spectrum of electron macroscopically degenerates. All the electron trajectories are closed circles that are classified by angular momentum and an additional integral of motion. Provided the complete filling of the lower Dirac zone, a universal value for Hall conductivity is found.

Classification Freshness of Red Snapper (Lutjanus Campechanus) Based on Eye Image Using Convolutional Neural Network

Indonesia is a maritime country where fish is the most widely extracted and consumed marine natural resource, one of which is snapper. Snapper contains high protein. Therefore, it is suitable for health. Red snapper or Lutjanus campechanus is one economical fish with a broad market share. Red snapper is a demersal fish group that ranks third with the most exported commodities after tuna and shrimp. In addition, snapper is one of the most common consumption fish in Indonesia. Therefore, the community needs to be able to identify the freshness of the fish. Fish freshness detection is done manually by touching the fish's body, eyes, and gills. However, this can cause accidental damage to the fish parts, which will be very detrimental. Several studies on identifying fish freshness explain that the VGGNet-16 Architecture on the Convolutional Neural Network algorithm is superior in its modeling performance. This research uses a different fish object, a red snapper object, with two different architectures from several previous studies, namely the Le-Net15 and VGGNet-16 architecture. This research focuses on the eye image carried out through the pre-processing data stage by cutting the fish body, followed by augmentation to reproduce the image data without losing its essence before training the dataset. The model will be trained using the Adam optimization method with very fresh and not fresh predictions. The experimental results of the classification of two classes of red snapper freshness using 600 fish images show that VGGNet-16 achieves the best performance compared to the LeNet-5 architecture, where the classification accuracy reaches 98.40%.

Three scleral ossicles in the West African Denticle herring Denticeps clupeoides (Clupeiformes: Denticipitidae).

The eyes of teleostean fishes typically exhibit two ossifications, the anterior and posterior sclerotics, both associated with the scleral cartilage. The West African Denticle herring Denticeps clupeoides has three scleral ossifications, including the typical two associated with the scleral cartilage (anterior and posterior sclerotic) and a third ossification (Di Dario's ossicle), spatially separated from the scleral cartilage and located within the anteromedial wall of the sclera. The medial rectus muscle inserts on the medial surface of Di Dario's ossicle, suggesting that this third sclerotic may play a role in forward rotation of the eye in this surface feeding fish.

Nondestructive prediction of freshness for bighead carp (Hypophthalmichthys nobilis) head by Excitation-Emission Matrix (EEM) analysis based on fish eye fluid: Comparison of BPNNs and RBFNNs

This study established back-propagation neural networks (BPNNs) and radial basis function neural networks (RBFNNs) models for evaluating the freshness of bighead carp head storage at different temperatures via the characteristic components of Excitation-Emission Matrix (EEM). Two characteristic components of EEM data of fish eye fluid were extracted by parallel factor analysis (PARAFAC) and were the most efficient components to stimulate fluorophores responsible for fish freshness detection during variable temperatures. EEM-RBFNNs and EEM-BPNNs models based on characteristic components of EEM used to predict the fish freshness. The results demonstrated the relative errors of EEM-BPNNs models for hiobarbituric acid reactive substances (TBARS) and total viable bacteria count (TAC) prediction were less than 10% which were better than those of EEM-RBFNNs models. It indicated that EEM-BPNNs model of bighead carp eye fluid by PARAFAC has a high potential for predicting fish freshness under variable storage conditions.

Combining MobileNetV1 and Depthwise Separable convolution bottleneck with Expansion for classifying the freshness of fish eyes

Image classification using Convolutional Neural Network (CNN) achieves optimal performance with a particular strategy. MobileNet reduces the parameter number for learning features by switching from the standard convolution paradigm to the depthwise separable convolution (DSC) paradigm. However, there are not enough features to learn for identifying the freshness of fish eyes. Furthermore, minor variances in features should not require complicated CNN architecture. In this paper, our first contribution proposed DSC Bottleneck with Expansion for learning features of the freshness of fish eyes with a Bottleneck Multiplier. The second contribution proposed Residual Transition to bridge current feature maps and skip connection feature maps to the next convolution block. The third contribution proposed MobileNetV1 Bottleneck with Expansion (MB-BE) for classifying the freshness of fish eyes. The result obtained from the Freshness of the Fish Eyes dataset shows that MB-BE outperformed other models such as original MobileNet, VGG16, Densenet, Nasnet Mobile with 63.21% accuracy.

Radio-frequency and optical techniques for evaluating anchovy freshness

The freshness of anchovies ( Engraulis Encrasicolus ) was estimated by radio-frequency and optical techniques in order to propose non-destructive and objective methods for rapid screening. Measurements were conducted until 7 days at 0 °C, storing the fish under ice. Image analysis, dielectric spectroscopy and hyperspectral images were conducted on fish eyes whilst mechanical properties were measured on the fish body. Evaluation of images by RGB scale highlighted differences due to ageing. Maximum force decreased as a function of degradation process time. Cluster analysis on dielectric spectra and 3D-principal component analysis on hyperspectral images of fish eyes revealed a good ability to characterise ageing modification demonstrating suitable methods for the development of a non-destructive, and rapid system for evaluation of fish freshness. • Anchovies freshness was measured by dielectric spectroscopy & hyperspectral imaging. • Dehydration of anchovy eyes was exploited for ageing estimation. • Multivariate approaches allowed to group the samples according to storage days. • Both techniques are rapid and contactless being promising for practical application.

Anatomy and Histology of the Eye of the Nutria Myocastor coypus: Evidence of Adaptation to a Semi-aquatic Life.

The nutria is a large, semi-aquatic rodent that, being invasive, is having a growing impact on the ecosystem in western Japan. Knowledge regarding physical adaptations to the nutria's lifestyle and habitual activities would be useful for effectively controlling and preventing their spread. Nutrias spend time on land and in water, feeding on agricultural crops and wild grasses growing near the waterside, as well as aquatic plants and shellfish. In the current study, the nutria's visual organ was analyzed anatomically and histologically, and aquatic and light environmental adaptations were evaluated. The results revealed that the nutria eyeball was almost spherical, and the cornea was rounded. The lens was convex and slightly thicker than previously reported for other rodents. These features were not characteristic of aquatic adaptations observed in the eyes of fish or marine mammals. The ratio of lens diameter to eyeball diameter was 0.6, similar to that of nocturnal species. The pupil was a vertical slit, suggesting an ability to adjust the amount of light entering the eyeball during twilight. Photoreceptors were sparsely distributed across the whole retina, and no fovea was observed. Retinal thickness was 90-100 μm, thinner than that in other rodent species. Visual acuity was 1.44-1.58 cycles/degree, higher than that in other rodents, likely because of the nutria's large eyeball and body. These results suggest that the nutria visual system is adapted to recognize large shadows of distant predators rather than viewing objects in detail.

Rare primary dyslipidaemias associated with low LDL and HDL cholesterol values in Portugal.

Background: Dyslipidaemia represents a group of disorders of lipid metabolism, characterized by either an increase or decrease in lipid particles, usually associated with triglycerides, LDL cholesterol (LDL-C) and/or HDL cholesterol (HDL-C). Most hyperlipidaemias and HDL deficiencies confer an increased cardiovascular risk, while hypolipidaemia, such as abeta or hypobetalipoproteinemia, may present different manifestations ranging from poor weight progression to neurological manifestations. The aim of this study is to present 7 cases with rare dyslipidaemias associated with low LDL or low HDL cholesterol values, referred to our laboratory for the genetic identification of the cause of the dyslipidaemia. Methods: Lipid profile was determined for each individual in an automated equipment Integra Cobas (Roche). Molecular analysis was performed by NGS with a target panel of 57 genes involved in lipid metabolism (Sure select QXT, Agilent) and samples were run in a NextSEQ Sequencer (Illumina). Only genes associated to rare forms of low HDL-c or LDL-c were analysed for this work, namely: ABCA1, APOA1, LCAT, SCARB1, APOB, PCSK9, MTTP, SAR1B, and ANGPTL3. All rare variants (MAF<5%) found in these genes were confirmed by Sanger sequencing. Results and discussion: This study includes 7 index cases (IC), with the following clinical diagnoses: Fish Eye Disease (1), Hypoalphalipoproteinemia (1) and Abetalipoproteinemia (ABL) / Familial Hypobetalipoproteinemia (FHBL) (5). We have identified one IC with a compound heterozygosity in LCAT causing Fish Eye Disease and one IC with a variant in ABCA1 in homozygosity causing Tangier disease. We found variants causing homozygous FHBL in 2 IC, one of whom has an undescribed pathogenic variant in homozygosity in APOB (c.12087+1G>A) and the other is a possible compound heterozygous for APOB variants c.2604+1G>A and c.4651C>T/p.(Gln1551*). In two patients only a variant in heterozygosity (c.3365delG/p.(Gly1122Vfs*62) and c.11095A>T/p.(Arg3699*)). In the remaining patient, no variants were identified. NGS proved to be a fundamental key for genetic testing of rare lipid disorders, allowing us to find the genetic cause of disease in 6/7 patients with low HDL-c and LDL-c. Patients with these rare conditions should be identified as early as possible in order to minimize or prevent clinical manifestations. The unsolved case is still under investigation.

Study of the Crack Propagation Property in Very-long Life Regime in Vacuum Environment of High Strength Steel

In general, high-strength steel is known to occur an internally initiated fatigue fracture called "Fish-eye failure" in the very long life region. In addition, the fatigue life of a fish-eye failure is dominated by the ODA (Optically Dark Area) that forms around the fracture origin. Therefore, it is necessary to elucidate the formative mechanism of ODA in order to predict the fatigue life of fish eye failure. Besides, it has been reported that small surface cracks propagate at extremely low speeds below the lattice spacing in a vacuum simulating the interior of high-strength steel. However, it has not been confirmed that the growth of these small cracks forms ODA. In this study, fatigue tests were conducted from a very short crack to a long crack, which corresponds to internal failure in the very long life region, instead of the fatigue tests with a relatively long crack of around 150 μm that have been conducted so far. The results of intermittent observation of the growth behavior and the relationship between the crack growth rate, stress intensity factor, and maximum stress suggest that small cracks grow and form ODAs.

Motion trajectory estimation of salmon using stereo vision

A main concern for the aquaculture industry is the fish behaviour and welfare. Motion trajectory analysis of salmon at aquaculture farming sites with respect to certain aquaculture operations aims to provide information about the behaviour and possibly stress level of the farmed salmon and may help to generate a general welfare indicator index. Towards this aim we present an innovative computer vision and machine learning based approach for motion trajectory estimation of salmon. Video footage was recorded with a stereo camera setup. Deep learning based object detection was performed to detect particular features. We focused on tracking the fish eyes and heads as a reliable indicators of the fish's position. Feature matching and subsequent 3D reconstruction was performed to calculate the 3D position of the fish from which trajectories of the fish movement were estimated. Related experiments were conducted at an aquaculture research facility under natural lighting conditions and extracted trajectories allowed a qualitative verification. The developed method was verified using synthetic ground truth data produced with an open source computer graphics software for quantifiable performance metrics.

Development and Performance Evaluation of Distance Measurements Detection Using 3 Axis Binocular Vision System

The world currently entering industry 4.0, which the industrial processes become automated and remotely control by computer with little input from human operators. Binocular vision is the result of signal sent to brain from eyes simultaneously which having advantage of depth perception. This project is about distance measurement of the object in 3-axis by using the advantages of binocular vision system. In this project, two webcams were used as binocular vision system to capture image and detect the distance measurement of the sample objects in 3-axis. The cameras must be calibrated before start to computing the distance measurement due to the fish eyes effect caused by the lens. In this project, the cameras were calibrated by using chessboard pattern with the size of 9x6 internal corners due to the simple geometry. The distance measurement algorithm will be executed once the cameras are calibrated, and the distance measurement is computed by using trigonometry concept.

Design and implementation of fish freshness detection algorithm using deep learning

Organoleptic assessment of fresh fish includes specifications for the quality of the eyes, gills, mucus, odor, texture and flesh (color and appearance). However, not everyone has knowledge about it. This research uses the tiny yolov2 to facilitate the determination of fish freshness levels (good quality, medium quality, poor quality) correctly and fast. There are a few stages in this research, included organoleptic test accompanied by taking fish eye image dataset every hour, processing organoleptic test data labeling, training, and validation. There are three types of fish used, consists of Rastrelliger, Euthynnus affinis, and Chanos chanos. Detection of fish freshness level for three species was successfully carried out with the result of average precision is 72.9%, average recall is 57.5%, and accuracy is 57.5%. The factors that affect the prediction results in this study is the collection of datasets before the training process is carried out consisting of fish samples obtained from traditional markets, which are considered inadequate so that it affects the organoleptic test process itself, the organoleptic test that was carried out as a reference for image sorting was considered inaccurate because it used less than 30 untrained panelists and dataset imbalance.

FATIGUE FAILURE AS A COMPLEX OF RELAXATION PROCESSES OCCURRED AT THE VERTICES OF THE STRESS RISERS

This paper considers the stress-dependent fatigue life of polycrystalline materials and their fatigue failure as a result of the relaxation processes that occurred on the stress risers of various scales: macroscopic stress risers of technological nature (pores, cracks, surface roughness, etc.), and microscopic stress risers at the grain/subgrain boundaries and/or second phase particles. Participation of the relaxation mechanisms plastic (vacancies and dislocation activities, grain boundary sliding) and brittle (cracks) nature in the process of the ‘fish eye’ fatigue crack formation is also addressed. The model described the parabolic dependencies of the densities of elementary carriers of plastic and brittle relaxations on the load change rate (i.e., on the growth rate of the stresses concentrated at the vertices of the stress risers) correlates well to the fatigue life data observed for the surface-modified metallic materials.

Maxwell fish eye for polarized light

We consider the propagation of polarized light in the medium with Maxwell fish eye refraction index profile. We show that polarization violates the additional symmetries of medium, so that ray trajectories no longer remain closed. Then we suggest a modified, polarization-dependent Maxwell fish eye refraction index which restores all symmetries of initial profile and yields closed trajectories of polarized light. Explicit expressions for the polarization dependent integrals of motion and the solutions of corresponding ray trajectories are presented.

Disturbed retinoid metabolism upon loss of rlbp1a impairs cone function and leads to subretinal lipid deposits and photoreceptor degeneration in the zebrafish retina.

The RLBP1 gene encodes the 36 kDa cellular retinaldehyde-binding protein, CRALBP, a soluble retinoid carrier, in the visual cycle of the eyes. Mutations in RLBP1 are associated with recessively inherited clinical phenotypes, including Bothnia dystrophy, retinitis pigmentosa, retinitis punctata albescens, fundus albipunctatus, and Newfoundland rod-cone dystrophy. However, the etiology of these retinal disorders is not well understood. Here, we generated homologous zebrafish models to bridge this knowledge gap. Duplication of the rlbp1 gene in zebrafish and cell-specific expression of the paralogs rlbp1a in the retinal pigment epithelium and rlbp1b in Müller glial cells allowed us to create intrinsically cell type-specific knockout fish lines. Using rlbp1a and rlbp1b single and double mutants, we investigated the pathological effects on visual function. Our analyses revealed that rlbp1a was essential for cone photoreceptor function and chromophore metabolism in the fish eyes. rlbp1a-mutant fish displayed reduced chromophore levels and attenuated cone photoreceptor responses to light stimuli. They accumulated 11-cis and all-trans-retinyl esters which displayed as enlarged lipid droplets in the RPE reminiscent of the subretinal yellow-white lesions in patients with RLBP1 mutations. During aging, these fish developed retinal thinning and cone and rod photoreceptor dystrophy. In contrast, rlbp1b mutants did not display impaired vision. The double mutant essentially replicated the phenotype of the rlbp1a single mutant. Together, our study showed that the rlbp1a zebrafish mutant recapitulated many features of human blinding diseases caused by RLBP1 mutations and provided novel insights into the pathways for chromophore regeneration of cone photoreceptors.

Amphibian and fish eye lens used as biomarker of remote and chronic environmental contamination

The lens of vertebrates has a general structural plan and reacts similarly to various factors of anthropogenic impact. Rainbow trout (Oncorhynchus mykiss) and grass frog (Rana temporaria L.) are the most well-studied objects of aquatic toxicology in Russia, which react to the level of exposure to toxicants in the urbanized environment and retain the consequences of this exposure. The study aims to determine the possibility of using the lens of fish and amphibians as a biomarker of chronic and long-term background environmental contamination. The fundamental importance of the work lies in the fact that for the first time the mechanisms of the response of the epithelial cells of the eye lens and lens fibers to the spectrum of various toxicants entering the environment with industrial effluents are considered. In chronic experiments, the sensitivity of the lens of Oncorhynchus mykiss fingerlings to three toxicants (dibutyl sebacate-DBS, polyterpenes-PTP, and 3-aminopropyltriethoxysilane-AGM-9) in concentrations close to the normalized valuesin the environment was studied. On adult individuals of Rana temporaria, the appearance of abnormities in the lens was studied over a long period, depending on the total environmental contamination. To assess remote environmental contamination, studies were carried out on the constantly growing lens of the grass frog, which can preserve the resulting fiber abnormities throughout its life in the form of local opacities from the harmful environmental factors impacts. On the epithelium of the lens of fish, it was found that under the influence of certain pollutants, the mitotic index (MI) in the germinal area can change over a wide range. With the combined effect of toxicants, inhibition of mitosis is also observed. Using biomicroscopy of the eye, it was possible to show that frogs from the urbanized zone of Moscow have 1.5 times more genotypic and modification changes in the lens than their relatives taken from an ecologically clean zone of the Moscow region, Mozhaisky district in the water area of the Ozerninskoye reservoir. For the first time, the sensitivity of the lens of aquatic organisms to chronic effects under experimental and background contamination of the terrestrial and aquatic environment has been shown. Therefore, taking into account the uniformity of the structure of the eye lens of fish and amphibians, as well as in other vertebrates, the lens can be used as a biomarker for assessing chronic and remote environmental contamination. The research results can be applied for a comprehensive assessment of the action of anthropogenic factors.

The association between Hsp70 and TNF-α as immune Response in Groupers Infected with Viral Nervous Necrosis

Along with the increasing expansion of aquaculture in recent years, fish diseases have become a major constraint which is quite challenging for the productivity and sustainability of the aquaculture industry. Especially the attack of Viral Nervous Necrosis (VNN) infects humpback grouper (Cromileptes altivelis) as one of the leading export commodities. The purpose of this study was to determine the immune response of kidney and eye tissue receptors for humpback grouper infected by Viral Nervous Necrosis (VNN) through flowcytometric analysis. The method used in this research is descriptive by comparing and analyzing the response of Heat Shock Protein-Hsp70 and TNFα in the kidney and eye tissue of healthy and VNN-infected grouper. The results of the flowcytometric analysis show an immune response in the brain, kidney and eye grouper tissue by the expression of Hsp70 as a stress response to cell and TNF-α as an acute inflammatory response to pathogenic infections. The analysis showed that Hsp70 in healthy grouper fish eye tissue was 8.51%, and VNN infected grouper was 10.90%. Healthy grouper fish kidney tissue was 2.51%, and VNN infected grouper was 8.37%. In comparison, TNF-α in eye tissue was 7.33% in healthy fish and 11.54% in VNN-infected fish, respectively. Then in the kidney tissue was 3.38% in healthy fish and 9.18% in VNN-infected fish. Serious infections can trigger TNF production or induce the expression of Hsp70 in large amounts, causing a systemic reaction. Hsp70 protein can act to protect cells from thermal or oxidative stress and able to induce pro-TNF-α production.

IFNγ as an Immune Response in Groupers Infected by Viral Nervous Necrosis

One of the diseases reported to have infected groupers is Viral Nervous Necrosis (VNN) which can cause mass mortality in the larval stage of up to 100%. The nervous system of the fish so that the fish will lose their nerve control, develop weakness in motion, and cause death. In fish teleost, interferon (IFN) plays an important role in non-specific responses, especially in maintaining viral infections in vertebrates. The purpose of this study was to determine the immune response of the brain, kidney, and eye tissue receptors of grouper infected with Viral Necrosis (VNN) through flowcytometric analysis. The method used in this research is descriptive by analyzing and analyzing the IFNγ response in the brain, kidney, and eye tissue of VNN-infected groupers and healthy fish through flowcytometric analysis. The results of flowcytometric analysis showed that there was an immune response formed in the brain, kidney, and mouse grouper tissue by forming qualitative immune cells, namely the IFNγ immune response as a pro-inflammatory response to cells. The analysis showed that the IFNγ response in healthy grouper fish brain tissue was 0.21%, and VNN-infected fish was 0.55%. Healthy grouper fish eyes were 14.05%, and VNN infected fish was 17.73%. Then the kidney tissue of healthy grouper was 8.54%, and grouper infected with VNN was 16.08%. The response of all organs showed that fish had higher IFNγ values. IFNγ is important in the system due in part to its ability to inhibit direct viral replication, and most importantly its immunomodulatory effect.