Optical Radiation Research Articles

Interactions of optic radiation lesions with retinal and brain atrophy in early multiple sclerosis.

Retrograde trans-synaptic neuroaxonal degeneration is considered a key pathological factor of subclinical retinal neuroaxonal damage in multiple sclerosis (MS). We aim to evaluate the longitudinal association of optic radiation (OR) lesion activity with retinal neuroaxonal damage and its role in correlations between retinal and brain atrophy in people with clinically isolated syndrome and early MS (pweMS). Eighty-five pweMS were retrospectively screened from a prospective cohort (Berlin CIS cohort). Participants underwent 3T magnetic resonance imaging (MRI) for OR lesion volume and brain atrophy measurements and optical coherence tomography (OCT) for retinal layer thickness measurements. All pweMS were followed with serial OCT and MRI over a median follow-up of 2.9 (interquartile range: 2.6-3.4) years. Eyes with a history of optic neuritis prior to study enrollment were excluded. Linear mixed models were used to analyze the association of retinal layer thinning with changes in OR lesion volume and brain atrophy. Macular ganglion cell-inner plexiform layer (GCIPL) thinning was more pronounced in pweMS with OR lesion volume increase during follow-up compared to those without (Difference: -0.82 μm [95% CI:-1.49 to -0.15], p = 0.018). Furthermore, GCIPL thinning correlated with both OR lesion volume increase (β [95% CI] = -0.27 [-0.50 to -0.03], p = 0.028) and brain atrophy (β [95% CI] = 0.47 [0.25 to 0.70], p < 0.001). Correlations of GCIPL changes with brain atrophy did not differ between pweMS with or without OR lesion increase ( = 5.92e-7 , p = 0.762). Faster GCIPL thinning rate is associated with increased OR lesion load. Our results support the value of GCIPL as a sensitive biomarker reflecting both posterior visual pathway pathology and global brain neurodegeneration.

Sensation seeking correlates with increased white matter integrity of structures associated with visuospatial processing in healthy adults.

The ability to process sensory information is an essential adaptive function, and hyper- or hypo-sensitive maladaptive profiles of responses to environmental stimuli generate sensory processing disorders linked to cognitive, affective, and behavioral alterations. Consequently, assessing sensory processing profiles might help research the vulnerability and resilience to mental disorders. The research on neuroradiological correlates of the sensory processing profiles is mainly limited to the young-age population or neurodevelopmental disorders. So, this study aims to examine the structural MRI correlates of sensory profiles in a sample of typically developed adults. We investigated structural cortical thickness (CT) and white matter integrity, through Diffusion Tensor Imaging (DTI), correlates of Adolescent/Adult Sensory Profile (AASP) questionnaire subscales in 57 typical developing subjects (34F; mean age: 32.7 ± 9.3). We found significant results only for the sensation seeking (STS) subscale. Positive and negative correlations emerged with fractional anisotropy (FA) and radial diffusivity (RD) in anterior thalamic radiation, optic radiation, superior longitudinal fasciculus, corpus callosum, and the cingulum bundle. No correlation between sensation seeking and whole brain cortical thickness was found. Overall, our results suggest a positive correlation between sensation seeking and higher white matter structural integrity in those tracts mainly involved in visuospatial processing but no correlation with gray matter structure. The enhanced structural integrity associated with sensation seeking may reflect a neurobiological substrate linked to active research of sensory stimuli and resilience to major psychiatric disorders like schizophrenia, bipolar disorder, and depression.

Using satellite multi-angle polarization measurements to characterize atmospheric aerosol above Bohai Bay

The paper analyzes data from the PARASOL optical multi-angle polarization radiometer over the waters of Bohai Bay under various atmospheric conditions and different seawater optical types. The study considered cases of clear atmosphere, haze, dust aerosol, and cloud coverage. The waters of Bohai Bay were categorized into areas heavily influenced by river inflows and relatively clear waters. By utilizing PARASOL data, the degree of polarization (DoP) values of optical radiation at scattering angles of about 90° between incident solar radiation and recorded radiation were determined. Appropriate scatterplots were created using measurements from the 490, 670, and 865 nm bands. Polarimetric pseudo-color maps were presented to classify various atmospheric states. The scatterplots successfully identified atmospheric dust, dust in clouds, haze, and water areas with high levels of suspended particles. The results obtained are consistent with the experience of using the Umov effect to study dust aerosol, which consists in the negative correlation between the maximum polarization of radiation and geometric albedo. The presence of suspended particles in water led to decrease in correlation coefficients between analyzed DoP at different wavelengths within the investigated sea area. The strong influence of river inflows on Bohai Bay in polarimetric data was observed only under clean atmospheric conditions.

Synchrotron radiation of a single electron application for optical spectroradiometry

Objectives. The investigations of optical radiation sources and metrological detector characteristics in the infrared (IR), visible, and air ultraviolet (UV) spectral regions are partially based on the unique metrological properties of synchrotron radiation. The aim of this work is to develop a high-precision method for determining the storage ring accelerated electron number with synchrotron radiation of a single electron to establish spectroradiometry and photometry units.Methods. By determining the number of accelerated electrons, any storage ring can be used to calculate the synchrotron radiation characteristics at wavelengths of many large then the critical wavelength in the visible, air UV, and IR regions of the spectrum. This makes it possible to determine the main metrological characteristics normalized to the number of electrons, such as luminous intensity, luminance, illuminance, radiant power, radiance, irradiance, etc., regardless of the energy of the electrons.Results. When applying the method for determining the number of accelerated electrons at low currents of the electronic storage ring, a total standard deviation of the number of accelerated electrons is less than 0.01% for an exposure range of the CCD matrix from 10−2 to 3 · 103 s in a wide dynamic range of 1−1010 electrons per orbit.Conclusions. The use of a CCD-based radiometer-comparator calibrated by responsivity on a synchrotron radiation source is particularly relevant in monitoring luminance contrast thresholds and spatial distribution of object and background brightness, as well as determining metrological characteristics of optoelectronic measuring instruments, including CCD cameras, radiometers, spectroradiometers and photometers.

The T1-weighted/T2-weighted ratio as a biomarker of anti-NMDA receptor encephalitis

BackgroundAnti-N-methyl-D-aspartate receptor (NMDAR) encephalitis rarely causes visible lesions in conventional MRI, yet advanced imaging detects extensive white matter damage. To improve prognostic capabilities, we evaluate the T1-weighted/T2-weighted (T1w/T2w) ratio, a...

Seasonal and Daily Variations in the Coefficient of Optical Radiation Extinction Due to Midges in the Surface Air in Western Siberia in Summer–Autumn 2018

Seasonal and Daily Variations in the Coefficient of Optical Radiation Extinction Due to Midges in the Surface Air in Western Siberia in Summer–Autumn 2018

Evaluation of Neurofibromatosis Type 1 Associated Optic Pathway Gliomas

Background/Aims: Optic pathway gliomas (OPGs) are low-grade gliomas histologically represented by pilocytic astrocytoma (PA) in 90% of cases, can develop from any part of the visual pathways such as optic nerve, chiasm, optic tract, or optic radiations which frequently involve the hypothalamus. OPGs account for 3–5% of childhood central nervous system (CNS) tumors and about 2% of pediatric glial lesions. OPGs are believed to be the most prevalent intracranial tumor in patients with neurofibromatosis type 1 (NF-1) and can occur in 15–20% of NF-1 cases. The aim of this study is to evaluate the clinical features and treatment response in patients diagnosed with optic glioma and NF-1.&#x0D; Methods: All cases diagnosed with OPG and received treatment in the Pediatric Oncology Department, between January 2015 to January 2021 were retrospectively evaluated. Inclusion criteria include children and adolescents with OPG aged between 0 and 18 years. The medical records (gender, age, tumor entity, tumor location) of patients, as well as their treatment history and magnetic resonance imaging (MRI) scans, were examined. The diagnosis of OPG was made clinically and radiologically by the tumor board. The recommendations of the Response Assessment in Pediatric Neuro-Oncology (RAPNO) working group were used in the diagnosis and evaluation of treatment response. Patients received intravenous chemotherapy with SIOP LGG 2004 (vincristine- carboplatin) with or without bevacizumab (10 mg/kg, started every 2 weeks), therapy or vinblastine (3 mg/m2, weekly). &#x0D; Results: This study included 27 cases during the study period from January 2015 to January 2021. In this study there were 14 male (51.8 %) and 13 female (48.1 %) patients. The median age was 4.8 (range: 0.5–14.9) years. Biopsy was performed in three patients and the diagnosis was low-grade glioma (pilocytic astrocytoma) for all of them. Chemotherapy was administered to 22 cases in total. Twelve patients received vincristine-carboplatine, 5 patients received vincristine-carboplatin with bevacizumab and 5 patients received vinorelbine. Radiological response was evaluated in all 22 patients at 3 months MRI. No patient had a radiological complete respons, 11 patients (50%) had partial response, 2 patients (9%) presented with a progressive disease, showing an increase in measurements of 35% and 9 patients(40.9%) had stable disease at the 3-month evaluation.&#x0D; Conclusions: Systemic and visual problems play a significant role in the selection of treatment for pediatric patients with optic gliomas. An essential treatment option for improving symptoms and reducing tumor size is systemic chemotherapy. A crucial therapy option for enhancing vision is bevacizumab for the patients with NF-associated OPG.

Optical Properties and Radiation Shielding Performance of Boron Silicate Glasses Containing CrO3 and SrTiO3

Optical Properties and Radiation Shielding Performance of Boron Silicate Glasses Containing CrO3 and SrTiO3

Preclinical Studies of the Antimicrobial and Wound-Healing Effects of the High-Intensity Optical Irradiation “Zarnitsa-A” Apparatus

In this paper, a new approach to treating infected wounds is proposed. It is based on treating the wound surface with high-intensity pulsed optical radiation with a continuous spectrum, continuously covering the entire UV range (from 200 to 400 nm) and the visible and near-infrared regions of the spectrum. A pulsed xenon lamp is used as a radiation source. A description of the design and technical characteristics of the device, “Zarnitsa-A”, is presented, implementing the proposed medical technology for wound therapy. The results of our studies of the apparatus in vitro and in vivo are also presented. The article shows that exposure to the apparatus leads to pronounced bactericidal- and wound-healing properties. The apparatus’s action reliably provides higher rates of wound healing compared with only a typical antibacterial or wound healing agent, such as “levomekol” ointment.

Survey Assessment of Utility in Preoperative Magnetic Resonance (MR) Tractography Surgical Planning

Although tractography-guided surgery is used by many surgeons, there is controversy in the published literature as it relates to its clinical utility. Here we adopted a survey-based approach with the goal of attaining a broader view of how tractography influence preoperative planning in a sampling of practicing neurosurgeons. Three cases were prepared where the presence of a tumor distorted the optic radiation (case 1), arcuate fasciculus (case 2), and corticospinal tract (case 3). This survey was administered at the Medtronic Cranial Consortium attended by 20 practicing neurosurgeons. To avoid commercial bias, we used both the Brainlab and Medtronic platform to compute tractography. Each participant is asked to vote on a surgical trajectory before and after seeing the tractography images, as well as whether tractography added value in validating their surgical approach. In the 3 cases surveyed, 16%-44% of the surgeons changed the surgical corridor selected after seeing the tractography images. The most common finding associated with a change in surgical corridor involved intersection of the surgical corridor with visualized tracts. Consistently, >80% of the surgeons surveyed felt that tractography added value in their surgical planning. The clinical utility of tractography in preoperative planning varies as a function of surgeon and the tumor anatomy, with >80% of the participating surgeons believing that tractography added value in preoperative surgical planning.

Assessing robustness of quantitative susceptibility-based MRI radiomic features in patients with multiple sclerosis

Multiple Sclerosis (MS) is an autoimmune demyelinating disease characterised by changes in iron and myelin content. These biomarkers are detectable by Quantitative Susceptibility Mapping (QSM), an advanced Magnetic Resonance Imaging technique detecting magnetic properties. When analysed with radiomic techniques that exploit its intrinsic quantitative nature, QSM may furnish biomarkers to facilitate early diagnosis of MS and timely assessment of progression. In this work, we explore the robustness of QSM radiomic features by varying the number of grey levels (GLs) and echo times (TEs), in a sample of healthy controls and patients with MS. We analysed the white matter in total and within six clinically relevant tracts, including the cortico-spinal tract and the optic radiation. After optimising the number of GLs (n = 64), at least 65% of features were robust for each Volume of Interest (VOI), with no difference (p > .05) between left and right hemispheres. Different outcomes in feature robustness among the VOIs depend on their characteristics, such as volume and variance of susceptibility values. This study validated the processing pipeline for robustness analysis and established the reliability of QSM-based radiomics features against GLs and TEs. Our results provide important insights for future radiomics studies using QSM in clinical applications.

High-temperature test of tin-lithium CPS under deuterium plasma irradiation conditions

This paper is devoted to experiments on testing of the Sn-Li capillary porous system (CPS) under conditions of deuterium plasma irradiation, carried out at a plasma-beam installation (PBI). As a metal CPS matrix, molybdenum mesh was used. The paper presents a detailed description of the development of technology and procedure for the fabrication of the investigated sample, intended for plasma testing, as well as experiments on irradiation of Sn-Li CPS with deuterium plasma. As a result of the experiments performed, the dependences of the temperature of the investigated sample on the energy of the plasma contacting with the CPS, time dependence of the gas phase composition in the PBI chamber during irradiation of Sn-Li CPS with deuterium plasma, optical spectra depending on the temperature were obtained. Post-experimental material science studies with a sample of Sn-Li CPS were also performed and the results of microstructure, thermal and X-ray phase analysis were obtained. Analysis of the experimental data obtained showed that the energy of deuterium plasma precipitated on the Sn-Li alloy is re-emitted into the energy of optical radiation on the evaporating neutral atoms of lithium and tin. A complete evaporation of the alloy from CPS, during interacting with deuterium plasma, leads to partial destruction of the metal matrix of molybdenum.

Fabrication of highly sensitive visible photodetector based on SnS2 Terrazzo-like structure for weak signal detection

Chemically inert and van der Waal-structured tin-disulfide (SnS2) has become a potential candidate for optoelectronics due to its ultra-sensitivity and high performance resulting from high light absorption coefficient and thickness-dependent electrical properties. We report the facile synthesis of SnS2 Terrazzo-like structure using the CVD technique. A highly responsive MSM SnS2-based device is designed to detect optical radiation ranging from 300 to 800 nm. The fabricated device exhibits excellent responsivity (external quantum efficiency) of 2240 mAW−1 (522%) under 532 nm wavelengths for a 5 μW optical signal. The other merits, like detectivity and noise equivalent power, are 1.4 × 1010 Jones and 2.6 × 10−12 WHz−1/2, respectively, with a linear dynamic range (LDR) of ∼41 dB. The low LDR plays a vital role in evaluating light intensity from the corresponding generated photocurrent. The weak optical signal detection capability of SnS2-based photodetector paves the way for its application in astronomy, communication systems, and biomedical imaging.

Probing AGN with spectropolarimetry: accretion disc and SMBH parameters

ABSTRACT The interaction of a supermassive black hole with the matter of an accretion disc in the presence of a magnetic field is the key mechanism of energy release in active galactic nuclei. However, determining the physical parameters of this system, such as the spin and mass of the black hole, the shape and parameters of the rotation of the accretion disc, and the geometry of the magnetic field in the accretion disc is a complex and not completely solved problem. We have previously shown, based on our numerical models, that these estimates can be obtained from just three parameters: the black hole mass, bolometric luminosity, and optical polarization. In this paper, we estimate the accretion disc and black hole parameters for a sample of 14 type 1 Seyfert galaxies. Using the spectropolarimetric data obtained by us, we selected only those objects in which the polarization of optical radiation is generated mainly by the mechanism in the accretion disc. Despite the small statistics, our results for such a sample are consistent with our previous conclusions and show a discrepancy between the disc magnetic field parameters and the classical Shakura–Sunyaev disc model.

Application of pairs of coupled microresonators for control of optical radiation: theoretical analysis

The paper presents an analysis of optical delay lines based on coupled ring microresonators. The introduced optical delay is caused by realization of a slow light mode in a system with high Q-factor. Using the method of slowly varying amplitudes, a theoretical analysis was carried out and an equation for the transfer function of the system under consideration was obtained. Using numerical simulation, the possibility of controlling the introduced delay and attenuation of the delayed signal was investigated. It follows from the numerical simulation that the proposed system of coupled resonators allows to change the delay in the range from 165 ps to 629 ps for a transmitted signal with a frequency band up to 300 MHz with a maximum attenuation of the delayed signal –4.7 dB.

A fast algorithm for decoding an object image in structured light for measuring a three-dimensional profi le in a non-linear optical path

The work is devoted to the development of image processing algorithms for measuring a three-dimensional surface profi le using phase triangulation methods. An algorithm for decoding images of an object in structured light is proposed, based on an iterative search for the minimum deviation of the model function from the measurement results and compensating for the nonlinearity of the receiving-transmitting path of the measuring complex. A distinctive feature of the proposed method is that the search for the model function is sought in the form of a polynomial of the second degree, which ensures the stability of the method against nonlinear distortions caused by power-law transformations of the receiving-transmitting path. The use of the interval search method as part of the proposed algorithm provides a qualitative reduction in its algorithmic complexity. It is shown that the proposed algorithm provides a stable search for the value of the initial phase shift in object images, is resistant to noise and non-linear distortions. The algorithm proposed in the paper can be used to process images received in three-dimensional scanning systems based on triangulation methods using structured illumination and phase triangulation. The proposed algorithm will be especially useful for data processing during the operation of measuring systems in the conditions of a nonlinear source-receiver path of optical radiation and measurement time limitations.

Investigations of Single-Mode Optical Fiber Microbending Properties

This research is devoted to the study of the properties of the microbending of an optical fiber. It is shown that an increase in the diameter of a microbend at a constant force in the area of its formation led to an increase in the power of optical radiation output from the fiber in the area of the microbend. It has been established that the smallest value of the optical radiation power branched in the microbending region and the smallest value of the radiation power loss at the microbending for the entire range of wavelengths under study is observed for the G657 optical fiber. The largest value of the radiation power branched off in the microbending region and the largest value of the radiation power loss at the microbending for the entire range of wavelengths under study is observed for the G655 optical fiber. The results of the article can be used in systems for protecting information transmitted over fiber-optic communication lines.

B2O3–P2O5–CaO bioactive glasses: Synthesis, physical properties, optical basicity, electronegativity and radiation attenuation competence

Seven bioactive glasses in the system (50-x) B2O3–4P2O5–26CaO–20Na2O-xZnO: (x = 0–15 mol%) have been produced using melt quenching route. The prepared samples coded as BG1-BG7. The physical properties, average optical basicity, electronegativity, electronic polarizability, and radiation attenuation competence of the BG1-BG7 glasses have been examined. Non-crystalline state of samples confirmed via the XRD measurements. Density increased from 2.6274 g/cm3 to 2.9406 g/cm3 for BG1 to BG7 samples. The average optical basicity (˄th) changed from 0.748 to 0.838, electronic polarizability, (α0−2) enhanced from 1.812 to 2.008, while electronegativity, (χav) reduced from 2.352 to 2.245 as ZnO increased from 0 to 15 mol%. The BG1 sample possessed the lowest values of both mass (MAC) –linear (LAC) -attenuation coefficients, while BG7 possessed the highest values. The sample contains higher ratio of ZnO (BG7) possessed the lowest values of half-value layer (HVL) and mean free path (MFP) among all BG-samples. Also, the HVL and MFP of all BG-samples were less than that of ordinary concrete (OC). The proposed bioactive samples can apply for several of medical applications.

Impacts of BaO additions on structure, linear/nonlinear optical properties and radiation shielding competence of BaO–NiO–ZnO–B2O3 glasses

The purpose of this research is to study the structure, optical and radiation shielding effectiveness of radiation shielding glasses based on the formula [x BaO–(80-X) B2O3– 1NiO–11ZnO]; x = 8, 16, 24 and 32 mol%] have been obtained from melt quenching method. The density was increased from 2.861 (± 0.001) g.cm−3 to 3.119 (± 0.001) g.cm−3 due to an effective concentration of BaO. Furthermore, the vibrational investigations confirmed the conversion from trigonally-coordinated boron units (B O3) to tetrahedrally-coordinated boron units (B O4) with progressive enhancement in tetrahedrally-coordinated boron ratio (N4), besides a significant deterioration in non-bridging oxygen units (NBOs) inside the glass network due to the further concentrations of BaO. Optical studies showed the increase in optical band gaps from 3.22 (± 0.01) eV to 3.40 (± 0.01) eV with further concentrations of BaO from 8 to 32 mol%. This increment was attributed to the reduced NBO concentrations inside the glass network. Moreover, the nonlinear optical parameters showed decreased values due to the effective addition of BaO. Furthermore, the radiation shielding studies showed that the addition of BaO to the present glasses is an effective way to improve their radiation shielding performance. Additionally, to better understand the radiation protection provided by these glasses, a comparison of their half-value layers (HVL) with those of previously reported glasses was carried out at 0.662 MeV of photon energies. This comparison confirmed the improved radiation shielding performance of the present glass system.

Multiband spectral response inspired by ultra-high responsive thermally stable and self-powered Sb2Se3/GaN heterojunction based photodetector

Hetero-structuring of dissimilar materials provides an exciting pathway to achieve unique electrical and optical properties based on application demand. A combination of Sb2Se3 and GaN is a potential candidate for optoelectronic applications owing to the notable carrier mobilities and absorption coefficient. The thermal stability, low optical signal detection capabilities, and broad range spectral response of Sb2Se3/GaN heterostructure self-powered photodetector are assessed. A stable Sb2Se3/GaN heterostructure-based two-terminal device with excellent photoresponsivity of 1210 mAW−1 (self-power) and 2.3 × 106 mAW−1 (photoconductive @ 12V) with extremely low optical signal detection capability (650 nW) is designed. The devices can detect optical radiation across a broad spectrum from Deep Ultraviolet (250 nm) to Short Wave Infrared (1250 nm). Additionally, the assessment of the device revealed a distinct high-temperature resilience limit that allowed it to work as a thermally stable broadband photodetector. The heterostructure-based optical device demonstrates ultrahigh responsivities of 844 mAW−1 and 1.2 × 106 mAW−1 at 250 °C in the photovoltaic (0V) and photoconductive (12V) modes, respectively. The Sb2Se3/GaN heterostructure-based detector provides an excellent perspective for the next generation of thermally stable optoelectronic devices. The analysis better explains how heterostructure provides thermal stability and offers a viable approach for developing high-performance, self-powered, thermally stable broadband optical detectors.