Retinal ischemia/reperfusion (I/R) injury is a common cause of visual impairment and blindness for which there remain limited treatment options. Nucleoside reverse transcriptase inhibitors (NRTIs), ...such as zidovudine (AZT), have been shown to block the NLRP3 inflammasome and prevent retinal degeneration in a mouse model of age-related macular degeneration. The NLRP3 inflammasome has also been shown to be triggered in I/R injury. Therefore, we studied the neuroprotective effects of AZT using a pressure-induced retinal ischemia mouse model.
C57BL/6J mice were randomly assigned to 1 of 2 treatment groups: vehicle-treated retinal I/R injury (
= 6) or AZT-treated retinal I/R injury (
= 6). Vehicle (1% dimethyl sulfoxide DMSO in phosphate-buffered saline PBS) or AZT 50 mg/kg in 1% DMSO in PBS were injected intraperitoneally twice daily for 5 days. On day 2 of treatment, retinal ischemia was induced by transient elevation of intraocular pressure for 45 min. Scotopic electroretinography (ERG) was used to quantify retinal function before and 1 week after retinal ischemic insult. Retinal morphology was examined 1 week after ischemic insult. Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assays and caspase 1 immunostaining was performed 24 h after retinal I/R injury.
Following I/R injury, ERG a- and b-wave amplitudes were significantly reduced in the vehicle-treated mice. AZT treatment significantly attenuated I/R-induced loss of retinal function as compared with vehicle-treated mice. Additionally, AZT-treated mice experienced significantly less inner retinal thinning as compared with vehicle-treated mice. TUNEL-positive cells were prevalent in the vehicle-treated I/R injury mouse retinas compared with the AZT-treated I/R injury mouse retinas. More caspase-1 immunoreactivity was detected in ganglion cell layer and inner nuclear layer (INL) in vehicle-treated I/R injury group than in AZT-treated I/R injury group.
AZT treatment resulted in relative preservation of retinal structure and function following ischemic insult as compared with controls. This suggests AZT may have therapeutic value in the management of retinal ischemic diseases.
Vehicle Detection and Recognition is a challenging move in the field of Traffic Management as it requires special attention and technique for the efficient management of vehicles. Vehicle Recognition ...and classification is a critical application of Intelligent Transport System (ITS). It is a process of identifying the moving vehicle on the road to analyze the flow rate and then accurately classify different objects. Lately, building an automatic onboard driver assistance system to assist drivers about possible collisions and clashes has received immense significance. Many researchers have proposed different methodologies using different source inputs to detect day and night vision vehicles. However, vehicle detection at night is an uphill task. It involves testing of classification algorithm under various factors such as Rainy weather, Snowy weather, Low illumination, etc., due to which identification of vehicle becomes a difficult task. This paper presents a comprehensive panorama of the work done so far by the researchers in vehicle detection day and night time. Various vehicle detection methods are discussed, along with the role of ITS in the application of vehicle detection and recognition. Also, it provides a concise review of the reported methods used for recognizing different types of vehicles in different environments and challenges faced by other researchers in their research area.
The recent availability of multiple avian genomes has laid the foundation for a huge variety of comparative genomics analyses including scans for changes and signatures of selection that arose from ...adaptions to new ecological niches. Nocturnal adaptation in birds, unlike in mammals, is comparatively recent, a fact that makes birds good candidates for identifying early genetic changes that support adaptation to dim‐light environments. In this review, we give examples of comparative genomics analyses that could shed light on mechanisms of adaptation to nocturnality. We present advantages and disadvantages of both “data‐driven” and “hypothesis‐driven” approaches that lead to the discovery of candidate genes and genetic changes promoting nocturnality. We anticipate that the accessibility of multiple genomes from the Genome 10K Project will allow a better understanding of evolutionary mechanisms and adaptation in general.
Comparative genomics is an exciting field that can pinpoint differences in genomic regions, which occur as a result of an environmental change. The future availability of multiple bird genomes opens an unprecedented era for research of mechanisms of nocturnal adaptation.
Background
Clinical trials that evaluate new medical products often use clinical outcome assessments to measure how patients feel or function. Determining the evidentiary support needed for clinical ...outcome assessments is challenging but necessary to ensure scores from a clinical outcome assessment reflect the relevant aspects of patients’ health. Modern validity theory—from educational and psychological testing—addresses the challenge by requiring that investigators state key assumptions underlying the proposed use of a clinical outcome assessment and collect evidence for or against those assumptions.
Methods
This article describes the argument-based approach to validity using an example of a performance outcome measure—the Multi-luminance Mobility Test—designed to assess patients with inherited retinal dystrophy that causes progressive loss of night vision. For the proposed interpretation and use of a performance outcome measure to be reasonable, several key assumptions need to be plausible. I describe the assumptions along with examples of supporting evidence from the published literature to evaluate each assumption within the rationale.
Results
This article provides an example of a validity rationale to evaluate a clinical outcome assessment using the Multi-luminance Mobility Test as an example.
Conclusion
The demonstration illustrates the use of the argument-based approach to validity evaluation and the challenges in supporting parts of a validity rationale for clinical outcome assessments that measure how patients feel and function in a more indirect way. By making clinical outcome assessment validation practices consistent with modern validity theory, investigators, sponsors, and regulators should be able to communicate more clearly and direct resources more efficiently to support the creation of patient-centered endpoints in clinical trials.
The growing need for the multiband photodetection of a single scene has promoted the development of both multispectral coupling and broadband detection technologies. Photodetectors operating across ...the infrared (IR) to terahertz (THz) regions have many applications such as in optical communications, sensing imaging, material identification, and biomedical detection. In this review, we present a comprehensive overview of the latest advances in broadband photodetectors operating in the infrared to terahertz range, highlighting their classification, operating principles, and performance characteristics. We discuss the challenges faced in achieving broadband detection and summarize various strategies employed to extend the spectral response of photodetectors. Lastly, we conclude by outlining future research directions in the field of broadband photodetection, including the utilization of novel materials, artificial microstructure, and integration schemes to overcome current limitations. These innovative methodologies have the potential to achieve high-performance, ultra-broadband photodetectors.
Review on Improved Image Fusion Approach Praveen Kumar, K; Arakeri, Megha P
Journal of physics. Conference series,
11/2019, Letnik:
1362, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Image fusion is the process of blending all the essential information from multiple images, and their incorporation into fewer images, generally a single one. The single image which is accessed by ...image fusion gives more information and is rigorous than any single source image. This image encompass all the important information. The image fusion is not only purposed to diminish the amount of data but also to frame images that are more convenient and pertinent for the machine and human approach. Certain situations in image processing need both high spectral and high dimensional information in a single image, which is important in remote sensing. Image fusion techniques involve filtering, enhancing and decomposing the images for better results. This paper emphases on the imperative and efficient approaches for image fusion.
To estimate heritability of parameters of human retinal electrophysiology and to explore which parameters change with age.
Prospective, classic twin study.
Adult monozygotic and dizygotic twin pairs ...recruited from the TwinsUK cohort.
Electroretinogram responses were recorded using conductive fiber electrodes in response to stimuli incorporating standards set by the International Society for the Clinical Electrophysiology of Vision. These parameters were extracted; in addition, photopic negative-response (PhNR; originating from retinal ganglion cells) and i-wave components were extracted from responses to the photopic single flash. Parameter values were averaged from both eyes.
Mean values were calculated for the cohort. Correlation coefficients with age were calculated (averaging parameters from both twins from each pair). Coefficients of intrapair correlation were calculated for monozygotic and dizygotic twins. Age-adjusted heritability estimates were derived using standard maximum likelihood structural equation twin modeling.
Responses were recorded from 210 participants in total (59 monozygotic and 46 dizygotic twin pairs). Ninety-three percent were women. Mean age for the cohort was 62.4 years (standard deviation, 11.4 years). In general, response amplitudes correlated negatively, and implicit times positively, with age. Correlations were statistically significant (P < 0.05) and moderate or strong (coefficient, >0.35) for the following parameters: scotopic standard and bright-flash a-wave implicit times, photopic 30-Hz flicker and single-flash b-wave implicit times, and PhNR and i-wave implicit times. Intrapair correlations were higher for monozygotic than dizygotic twins, suggesting important genetic influences. Age-adjusted estimates of heritability were significant for all parameters (except scotopic dim-flash b-wave implicit time), ranging from 0.34 to 0.85. Highest estimates were for photopic single-flash a-wave and b-wave amplitudes (0.84 and 0.85, respectively).
This study explored heritability of retinal electrophysiologic parameters and included measurements reflecting ganglion cell function. Most parameters showed significant heritability, indicating that genetic factors are important, determining up to 85% of the variance in some cone system response parameters. Scotopic responses tended to show lower heritability (possibly relating to greater rod system susceptibility to environmental factors). Future studies can explore the identity of these genetic factors, improving our understanding of how they shape retinal function.
The appaloosa coat spotting pattern in horses is caused by a single incomplete dominant gene (LP). Homozygosity for LP (LP/LP) is directly associated with congenital stationary night blindness (CSNB) ...in Appaloosa horses. LP maps to a 6-cM region on ECA1. We investigated the relative expression of two functional candidate genes located in this LP candidate region (TRPM1 and OCA2), as well as three other linked loci (TJP1, MTMR10, and OTUD7A) by quantitative real-time RT-PCR. No large differences were found for expression levels of TJP1, MTMR10, OTUD7A, and OCA2. However, TRPM1 (Transient Receptor Potential Cation Channel, Subfamily M, Member 1) expression in the retina of homozygous appaloosa horses was 0.05% the level found in non-appaloosa horses (R = 0.0005). This constitutes a >1800-fold change (FC) decrease in TRPM1 gene expression in the retina (FC = -1870.637, P = 0.001) of CSNB-affected (LP/LP) horses. TRPM1 was also downregulated in LP/LP pigmented skin (R = 0.005, FC = -193.963, P = 0.001) and in LP/LP unpigmented skin (R = 0.003, FC = -288.686, P = 0.001) and was downregulated to a lesser extent in LP/lp unpigmented skin (R = 0.027, FC = -36.583, P = 0.001). TRP proteins are thought to have a role in controlling intracellular Ca(2+) concentration. Decreased expression of TRPM1 in the eye and the skin may alter bipolar cell signaling as well as melanocyte function, thus causing both CSNB and LP in horses.
Object detection in thermal images is an important computer vision task and has many applications such as unmanned vehicles, robotics, surveillance, and night vision. Deep learning-based detectors ...have achieved major progress, which usually need large amount of labelled training data. However, labelled data for object detection in thermal images is scarce and expensive to collect. How to take advantage of the large number labelled visible images and adapt them into thermal image domain is expected to solve. This paper proposes an unsupervised image-generation enhanced adaptation method for object detection in thermal images. To reduce the gap between visible domain and thermal domain, the proposed method manages to generate simulated fake thermal images that are similar to the target images and preserves the annotation information of the visible source domain. The image generation includes a CycleGAN-based image-to-image translation and an intensity inversion transformation. Generated fake thermal images are used as renewed source domain, and then the off-the-shelf domain adaptive faster RCNN is utilized to reduce the gap between the generated intermediate domain and the thermal target domain. Experiments demonstrate the effectiveness and superiority of the proposed method.
Phentolamine mesylate ophthalmic solution (PMOS), applied to the eye topically, was shown previously to have beneficial effects in patients with dim light vision disturbances (DLD), including ...decreased pupil diameter (PD), improved best-corrected distance visual acuity (BCDVA), as well as lower intraocular pressure (IOP). The ORION-1 trial evaluated the long-term safety and efficacy of PMOS in a glaucomatous, presbyopic population.
In this randomized, double-masked, multi-center, placebo-controlled, multiple-dose Phase 2b trial, 39 patients with elevated IOP were randomized to receive one evening dose of study medication or placebo for 14 days. The primary outcome measure was mean change in diurnal IOP, and the key secondary outcome measures included changes in PD, distance-corrected near visual acuity (DCNVA), and conjunctival hyperemia.
Use of 1% PMOS did not lead to a statistically significant decrease in diurnal IOP compared to placebo (
= 0.89) but trended toward a greater decrease in patients with lower IOP baselines. PMOS produced a statistically significant mean 20% PD reduction under both photopic and mesopic conditions that was sustained for 36 hours post-dosing. A statistically significant number of patients with PMOS compared to placebo demonstrated ≥1 line of improvement in photopic DCNVA at day 8 (
= 0.0018), day 15 (
= 0.0072), and day 16 (
= 0.0163), with a trend for 2- and 3-line improvements at all time points. There was no statistical difference in conjunctival hyperemia compared to placebo.
Although mean IOP was not lowered significantly, daily evening dosing of 1% PMOS was found to be well tolerated with no daytime conjunctival redness and demonstrated improvement in DCNVA with sustained PD reduction in a glaucomatous and presbyopic population. Smaller pupil size can have beneficial effects in improving symptoms of presbyopia and DLD, which will be the focus of further studies.
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