Ultraviolet Band Research Articles

Evaluation the efficacy of NB-UVB treatment alone in comparison with combination therapy of NB-UVB and oral prednisolone in treatment of vitiligo

Background: The treatment landscape for vitiligo has witnessed diverse approaches yielding variable outcomes. Objective: To discern the optimal approach in terms of both tolerability and efficacy by comparing Narrow Band Ultraviolet B (NB-UVB) phototherapy with adjunctive oral mini pulse (OMP) prednisolone tablets. Patients and Methods: A total of eighty-seven individuals with progressive vitiligo were enrolled in a one-year study, with participants allocated randomly across three study groups through a continuous selection method. Group 1 received a combination of NB-UVB and OMP prednisolone tablets, group 2 underwent NB-UVB treatment only, and group 3 received OMP prednisolone tablets alone. Clinical assessments were conducted at three- and six-month intervals, and statistical analyses were performed utilizing descriptive and bivariate techniques, including the chi-square test, to gauge the significance of differences between the various groups. Results: In Group 1 (NB-UVB + OMP), substantial improvement was observed in 41.4%, accompanied by moderate improvement in 44.8% of patients. Group 2 (NB-UVB) demonstrated marked improvement in 31.0% and moderate improvement in 38.0%. In Group 3 (OMP), a lower proportion experienced marked (13.8%) or moderate (3.4%) improvement. Chi-square test findings indicated that the combination of NB-UVB and OMP correlated significantly with marked and moderate improvement in contrast to OMP alone, with respective values of χ² = 6.434 (p = 0.001) and χ² = 7.831 (p = 0.015) after a six-month follow-up. Conclusion: Through a comprehensive evaluation of three treatment modalities in vitiligo patients, it was established that the sole application of oral mini pulse steroids (OMP) held an adjunctive value, lacking substantial efficacy on its own. Remarkably, the amalgamation of Narrow Band UVB and OMP presented a clear advantage over either treatment administered independently.

Evaluation the Efficacy of NB-UVB Treatment Alone in Comparison with Combination Therapy of NB-UVB and Oral Prednisolone in Treatment of Vitiligo

Background: The treatment landscape for vitiligo has witnessed diverse approaches yielding variable outcomes. Objective: To discern the optimal approach in terms of both tolerability and efficacy by comparing Narrow Band Ultraviolet B (NB-UVB) phototherapy with adjunctive oral mini pulse (OMP) prednisolone tablets. Patients and Methods: A total of eighty-seven individuals with progressive vitiligo were enrolled in a one-year study, with participants allocated randomly across three study groups through a continuous selection method. Group 1 received a combination of NB-UVB and OMP prednisolone tablets, group 2 underwent NB-UVB treatment only, and group 3 received OMP prednisolone tablets alone. Clinical assessments were conducted at three- and six-month intervals, and statistical analyses were performed utilizing descriptive and bivariate techniques, including the chi-square test, to gauge the significance of differences between the various groups. Results: In Group 1 (NB-UVB + OMP), substantial improvement was observed in 41.4%, accompanied by moderate improvement in 44.8% of patients. Group 2 (NB-UVB) demonstrated marked improvement in 31.0% and moderate improvement in 38.0%. In Group 3 (OMP), a lower proportion experienced marked (13.8%) or moderate (3.4%) improvement. Chi-square test findings indicated that the combination of NB-UVB and OMP correlated significantly with marked and moderate improvement in contrast to OMP alone, with respective values of χ² = 6.434 (p = 0.001) and χ² = 7.831 (p = 0.015) after a six-month follow-up. Conclusion: Through a comprehensive evaluation of three treatment modalities in vitiligo patients, it was established that the sole application of oral mini pulse steroids (OMP) held an adjunctive value, lacking substantial efficacy on its own. Remarkably, the amalgamation of Narrow Band UVB and OMP presented a clear advantage over either treatment administered independently. Keywords: Vitiligo, NB-UVB, OMP, Prednisolone.

Direct Drive Laser Fusion Facility and Pilot Plant

Direct-drive laser inertial fusion is a potential producer of baseline power that has increased credibility following the achievement at the National Ignition Facility of ignition and net gain using indirect-drive via laser-produced X-rays. Ultraviolet broad band lasers such as argon fluoride, at 193 nm and 10 THz, are predicted by hydrocode simulations to enable energy gains greater than 100 with laser energies less than 0.5 MJ, stimulating renewed reactor design effort in anticipation of experimental verification. The present study attempts to create a reactor design with very few unknowns in materials, corrosion, first wall viability, tritium breeding and ease of servicing. A new variant of magnetic intervention has an increased ion dump surface area combined with a simple structure. Around an inner vacuum vessel an all-ceramic tritium breeder blanket is possible in an unconstrained volume, allowing helium coolant to be used without excessive pressure or flow power. The case is made for development of a lead (Pb) ceramic as the neutron multiplier.

A Double-Blinded Placebo Controlled Therapeutic Trial on Patients with Stable Non-Segmental Vitiligo Using A Specially Formulated Reducing Gel [Pseudo-Catalase] Enhanced by Narrow Band Ultraviolet B Exposure

A Double-Blinded Placebo Controlled Therapeutic Trial on Patients with Stable Non-Segmental Vitiligo Using A Specially Formulated Reducing Gel [Pseudo-Catalase] Enhanced by Narrow Band Ultraviolet B Exposure

In-water lidar simulations: the ALADIN ADM-Aeolus backscattered signal at 355 nm.

The Lidar Ocean Color (LiOC) Monte Carlo code has been developed to simulate the in-water propagation of the lidar beam emitted by the ALADIN ADM-Aeolus instrument in the ultraviolet (UV) spectral region (∼ 355 nm). To this end, LiOC accounts for reflection/transmission processes at the sea surface, absorption and multiple scattering in the water volume, and reflection from the sea bottom. The water volume components included in the model are pure seawater, Chlorophyll-a concentration (Chl-a), Colored Dissolved Organic Matter (CDOM), and/or a generic absorbing species. By considering the transmission/reception measurement geometry of ALADIN ADM-Aeolus, the study documents the variability of the normalized backscattered signal in different bio-optical conditions. The potential for data product retrieval based on information at 355 nm is considered by developing a demonstrative lookup table to estimate the absorption budget exceeding that explained by Chl-a. Results acknowledge the interest of space programs in exploiting UV bands for ocean color remote sensing, as, for instance, addressed by the PACE mission of NASA.

Design of a compact wide-band triple grating imaging spectrometer based on freeform surfaces

Wide-band, high spectral resolution, and miniaturized imaging spectrometers have important applications. However, the working band, spectral resolution, and volume of the imaging spectrometers are mutually restricted. To solve this problem, we proposed a method in which multiple working bands share the same optical components except gratings, and the working bands switch with the switching of the working gratings. Based on the freeform surfaces characterized by XY polynomials, we designed a compact wide-band triple grating imaging spectrometer through the design ideas of human-computer interaction and iterative optimization. The imaging spectrometer works in the wavelength band of 200nm∼1600nm, covering ultraviolet (UV), visible, and near-infrared light, and it has a compact optical path volume of 24mm×38mm×80mm. Three gratings with 0.0025 mm, 0.005 mm, and 0.01 mm line spacing are used to realize dispersion with high diffraction efficiency in the bands of 200nm∼400nm, 400nm∼800nm, and 800nm∼1600nm, respectively. The UV detector receives imaging light in the UV band (200nm∼400nm), and the visible near-infrared (VNIR) detector receives imaging light in the visible and near-infrared bands (400nm∼1600nm). The design results show that the spectral resolutions of the three bands are 0.4 nm, 0.8 nm, and 1.6 nm, and the spectral smile and keystone distortion are less than 1.4 µm. The design results have engineering application value.

AGNfitter-rx : Modeling the radio-to-X-ray spectral energy distributions of AGNs

We present new advancements in the modeling of the spectral energy distributions (SEDs) of active galaxies by introducing the radio-to-X-ray fitting capabilities of the publicly available Bayesian code AGNfitter . The new code release, called AGNfitter-rx models the broad-band photometry covering the radio, infrared (IR), optical, ultraviolet (UV), and X-ray bands consistently using a combination of theoretical and semi-empirical models of the active galactic nucleus (AGN) and host-galaxy emission. This framework enables the detailed characterization of four physical components of the active nuclei, namely the accretion disk, the hot dusty torus, the relativistic jets and core radio emission, and the hot corona, and can be used to model three components within the host galaxy: stellar populations, cold dust, and the radio emission from the star-forming regions. Applying AGNfitter-rx to a diverse sample of 36 AGN SEDs at $z 0.7$ from the AGN SED ATLAS, we investigated and compared the performance of state-of-the-art torus and accretion disk emission models in terms of fit quality and inferred physical parameters. We find that clumpy torus models that include polar winds and semi-empirical accretion disk templates including emission-line features significantly increase the fit quality in 67<!PCT!> of the sources by reducing by $2 fit residuals in the $1.5-5 1mm m$ and $0.7 1mm m$ regimes. We demonstrate that, by applying AGNfitter-rx to photometric data, we are able to estimate the inclination and opening angles of the torus, consistent with spectroscopic classifications within the AGN unified model, as well as black hole masses congruent with virial estimates based on Halpha . We investigate wavelength-dependent AGN fractions across the spectrum for Type 1 and Type 2 AGNs, finding dominant AGN fractions in radio, mid-infrared, and X-ray bands, which are in agreement with the findings from empirical methods for AGN selection. The wavelength coverage and the flexibility for the inclusion of state-of-the-art theoretical models make AGNfitter-rx a unique tool for the further development of SED modeling for AGNs in present and future radio-to-X-ray galaxy surveys.

Multiwavelength radiation from the interaction between magnetar bursts and a companion star in a binary system

Magnetars are young, highly magnetized neutron stars that are associated with magnetar short bursts (MSBs), magnetar giant flares (MGFs), and at least some fast radio bursts (FRBs). In this work, we consider a magnetar and a main sequence star in a binary system and analyze the properties of the electromagnetic signals generated by the interaction between the magnetar bursts and the companion star. During the preburst period, persistent radiation could be generated by the interaction between the $e^+e^-$-pair wind from the magnetar and the companion or its stellar wind. We find that for a newborn magnetar, the persistent preburst radiation from the strong magnetar wind can be dominant, and it is mainly at the optical and ultraviolet (UV) bands. For relatively old magnetars, the re-emission from a burst interacting with the companion is larger than the persistent preburst radiation and the luminosity of the companion itself. The transient re-emission produced by the heating process has a duration of $0.1 - 10^5 s $ at the optical, UV, and X-ray bands. Additionally, we find that if these phenomena occur in nearby galaxies within a few hundred kiloparsecs, they could be detected by current or future optical telescopes.

High performance La1-xAlxF3 nanocomposite coatings prepared by a co-evaporation technique.

La1-xAlxF3 nanocomposite coatings with various amounts of AlF3 in LaF3 were deposited on the fused silica substrate using double-source electron beam co-evaporation. The effects of the material composition on the chemical composition, optical properties, microstructure properties, and residual stress of these deposited coatings were investigated. The results showed that although the doping of AlF3 led to a reduction in the refractive index, the overall performance of the nanocomposites showed remarkable improvement. The increase in the AlF3 content of prepared nanocomposites caused a decrease in the crystallinity, surface roughness, residual stress, and optical loss. Compared to polycrystalline LaF3, the La1-xAlxF3 nanocomposite (x ≥ 0.3) retained an amorphous structure, showcasing smooth surface morphology and lower absorption. As a result, the total optical loss was reduced. Additionally, the tensile stress was also mitigated to a certain extent, which means that the nanocomposite material was less prone to cracking. Finally, a 193 nm-La0.70Al0.30F3/AlF3 high reflective coating was prepared, which achieved an improved reflectance of 98.7% and better film quality compared to the pure LaF3/AlF3 sample. These findings clearly indicate the significant potential of La1-xAlxF3 nanocomposites for developing deep ultraviolet band thin films, extending even into the vacuum ultraviolet band.

Computational study of K vacancy with an H interstitial defect in [formula omitted] crystal

The electronic structures, defect formations, defect transition levels and optical properties for VK+Hi defect models in KDP crystals have been studied based on DFT. Lattice dynamics methods give the most reasonable compensation mechanism for VK, namely compensation with the third-nearest Hi neighbor from VK for the paraelectric (PE) phase and compensation with the fourth-nearest neighbor Hi from VK for the ferroelectric (FE) phase. The defect formation energies indicate that the (VK+Hi)x (The superscript represents the charged state, the ‘x’ represents neutral, ‘’’ represents −1 charge state and ‘.’ represents +1 charge state.) is the main defect type in this kind of defect cluster and a self-trapped electron is located at Hi in the (VK + Hi)′ system. For (VK+Hi)x system, one electron is accommodated in VK. There is not a new defect state in the band gap. The Hi bonds with the O ion (0.99 Å) form a hydroxyl. For (VK + Hi)′ system, the hydroxyl is broken, the Hi exists in an atomic form and introduces new defect states in the band gap. As the large relaxation energy leads to a large Huang-Rhys factor, the Stokes red shifts will significantly affect the optical properties. A broad ultraviolet (UV) absorption band and emission band range from UV to visible are obtained originating from the defect cluster. We believe that the far-violet absorption peaks (167 nm and 179 nm) caused by defect cluster VK+Hi can significantly impact the optical damage threshold of the KDP.

Synthesis of 2D Gallium Sulfide with Ultraviolet Emission by MOCVD.

Two-dimensional (2D) materials exhibit the potential to transform semiconductor technology. Their rich compositional and stacking varieties allow tailoring materials' properties toward device applications. Monolayer to multilayer gallium sulfide (GaS) with its ultraviolet band gap, which can be tuned by varying the layer number, holds promise for solar-blind photodiodes and light-emitting diodes as applications. However, achieving commercial viability requires wafer-scale integration, contrasting with established, limited methods such as mechanical exfoliation. Here the one-step synthesis of 2D GaS is introduced via metal-organic chemical vapor deposition on sapphire substrates. The pulsed-mode deposition of industry-standard precursors promotes 2D growth by inhibiting the vapor phase and on-surface pre-reactions. The interface chemistry with the growth of a Ga adlayer that results in an epitaxial relationship is revealed. Probing structure and composition validate thin-film quality and 2D nature with the possibility to control the thickness by the number of GaS pulses. The results highlight the adaptability of established growth facilities for producing atomically thin to multilayered 2D semiconductor materials, paving the way for practical applications.

Design and analysis of polarization-insensitive molybdenum-based ultra-wideband solar energy absorber with wide-incident-angle

We introduce an ultra-wideband absorber with a molybdenum and Al2O3 multilayer structure for solar energy harvesting. The proposed structure could maintain its structural integrity at high temperatures thanks to the refractory materials used in its construction. Under normal incidence of optical waves, absorption of more than 90% is achieved throughout a broad range of wavelengths from 300 nm to approximately 3177 nm with a bandwidth of 2877 nm which covers ultraviolet, visible, and near-infrared spectral bands. The average absorption in that band is calculated to be 96.46%. The proposed design’s symmetrical characteristic makes the absorber insensitive to the polarization of the incident optical wave. Furthermore, throughout a broad range of optical wave angles of incidence for both transverse electric and transverse magnetic polarizations, the absorber supports absorptivity greater than 80%.

Preflight Spectral Calibration of the Ozone Monitoring Suite-Nadir on FengYun 3F Satellite

The Ozone Monitoring Suite-Nadir (OMS-N) instrument is the first hyperspectral remote sensor in the ultraviolet band of China’s Fengyun series satellites. It can be used to detect several kinds of atmospheric constituents. This paper describes the prelaunch spectral calibration of the OMS-N onboard FengYun 3F. Several critical spectral parameters including the spectral resolution, spectral dispersion, and the instrument spectral response function were determined through laser-based measurements. A secondary peak of the instrument spectral response function from the short wavelength side of the ultraviolet band was found, and the possible influence on data applications was analyzed using a reference solar model and radiative transfer model. The results indicate that the spectral resolution and spectral accuracy of OMS-N meet the mission requirements. However, the asymmetries in the instrument spectral response function in the ultraviolet band were found near nadir rows, which are expressed as the “asymmetric central peak” and “secondary peak”. The analysis results show that if the influences of the instrument spectral response function “asymmetric central peak” and “secondary peak” in the ultraviolet band are ignored, they will bring an error as large as 5% at the center of the absorption line.

Nowcasting Solar EUV Irradiance With Photospheric Magnetic Fields and the Mg II Index

AbstractA new method to nowcast spectral irradiance in extreme ultraviolet (EUV) and far ultraviolet (FUV) bands is presented here, utilizing only solar photospheric magnetograms and the Mg II index (i.e., the core‐to‐wing ratio). The EUV and FUV modeling outlined here is a direct extension of the SIFT (Solar Indices Forecasting Tool) model, based on Henney et al. (2015, https://doi.org/10.1002/2014sw001118). SIFT estimates solar activity indices using the earth‐side solar photospheric magnetic field sums from global magnetic maps generated by the ADAPT (Air Force Data Assimilative Photospheric Flux Transport) model. Utilizing strong and weak magnetic field sums from ADAPT maps, Henney et al. (2015, https://doi.org/10.1002/2014sw001118) showed that EUV & FUV observations can also be well modeled using this technique. However, the original forecasting method required a recent observation of each SIFT model output to determine and apply a 0‐day offset. The new method described here expands the SIFT and ADAPT modeling to nowcast the observed Mg II index with a Pearson correlation coefficient of 0.982. By correlating the Mg II model‐observation difference with the model‐observation difference in the EUV & FUV channels, Mg II can be used to apply the 0‐day offset correction yielding improvements in modeling each of the 37 studied EUV & FUV bands. With daily global photospheric magnetic maps and Mg II index observations, this study provides an improved method of nowcasting EUV & FUV bands used to drive thermospheric and ionospheric modeling.

Structural and optical properties of position-controlled n-ZnO nanowire arrays: Potential applications in optoelectronics

Highly position-controlled ZnO nanowire (NW) arrays and nanowire-cluster (NW–C) arrays are grown on mask-patterned gallium nitride (GaN) substrates by hydrothermal method. Electroluminescence (EL) emissions with blue-violet light at forward-bias(fb) voltage, EL emissions with yellow light at reverse-bias(rb) voltage, and EL emission at both rb voltages and rb voltages were achieved by the adjustment of the size of the heterojunction interface between wire arrays and film. The high rb current is attributed to electron tunneling transport edge effect via a narrow tunnel barrier. The obtained results highlight that the EL characteristics of ZnO NWs can be tuned and controlled through the size of the heterojunction interface between wire arrays and film. Besides, the nonplanar heterogeneous structure of ZnO NW arrays/GaN film also shown a great spectral response characteristic in the ultraviolet(UV) band, which proves that the structure of is worthy of being studied to achieve high performance UV photodetectors.

Cadmium Hydroxyl Chloride with Balanced Band Gap and Second-Harmonic-Generation Response.

Ultraviolet (UV) nonlinear-optical (NLO) materials are crucial in laser technology due to their ability to modulate light frequency. In this work, when d10 cations, hydroxyl groups, and Cl atoms were combined, a cadmium double salt, Cd(OH)Cl, was synthesized by a simple hydrothermal method. It has a large phase-matched second-harmonic-generation (SHG) response at 1064 nm (2.5 × KDP) with a short UV-cutoff edge (260 nm), which can be applied in a solar-blind UV band. Theoretical calculations suggest that [Cd(OH)3Cl3] groups lead to a large SHG response. Our work may shed light on the exploration of new NLO materials in metal hydroxyl chlorides.

Electronic transport and optical properties of five different phases (α, β, ε, δ and γ) of Ga2O3: A first-principles study

In the field of power and ultraviolet devices, Ga2O3 becomes an emerging semiconductor due to its large energy bandgap and suitable optical absorption wavelength at solar blind ultraviolet band. In this work, the electronic and optical properties of five Ga2O3 polymorphs are investigated by the first-principles calculations to study their potential in ultraviolet devices. The geometry structures, electronic structure, optical and electronic transport properties of five polymorphs have been investigated through GGA + U approach and deformation potential theory. Based on the deformation potential theory, the anisotropic electron mobility of five Ga2O3 polycrystals is obtained by analyzing the parameters obtained from the first-principles calculation. TCAD simulations using calculation results before show the spectral response of MSM solar-blind detectors based on five polymorphs, and indicating that ε-Ga2O3 is the best candidate material for solar blind UV detector. This work provides theoretical insights for the preparation of different phase gallium oxide materials and devices.

Multiband analyses of the bright GRB 230812B and the associated SN2023pel

ABSTRACT GRB 230812B is a bright and relatively nearby (z = 0.36) long gamma-ray burst (GRB) that has generated significant interest in the community and has thus been observed over the entire electromagnetic spectrum. We report over 80 observations in X-ray, ultraviolet, optical, infrared, and submillimetre bands from the GRANDMA (Global Rapid Advanced Network for Multimessenger Addicts) network of observatories and from observational partners. Adding complementary data from the literature, we then derive essential physical parameters associated with the ejecta and external properties (i.e. the geometry and environment) of the GRB and compare with other analyses of this event. We spectroscopically confirm the presence of an associated supernova, SN2023pel, and we derive a photospheric expansion velocity of v ∼ 17 × 103 km s−1. We analyse the photometric data first using empirical fits of the flux and then with full Bayesian inference. We again strongly establish the presence of a supernova in the data, with a maximum (pseudo-)bolometric luminosity of 5.75 × 1042 erg s−1, at $15.76^{+0.81}_{-1.21}$ d (in the observer frame) after the trigger, with a half-max time width of 22.0 d. We compare these values with those of SN1998bw, SN2006aj, and SN2013dx. Our best-fitting model favours a very low density environment ($\log _{10}({n_{\rm ISM}/{\rm cm}^{-3}}) = -2.38^{+1.45}_{-1.60}$) and small values for the jet’s core angle $\theta _{\rm core} = 1.54^{+1.02}_{-0.81} \ \rm {deg}$ and viewing angle $\theta _{\rm obs} = 0.76^{+1.29}_{-0.76} \ \rm {deg}$. GRB 230812B is thus one of the best observed afterglows with a distinctive supernova bump.

Single-Mode Control and Individual Nanoparticle Detection in the Ultraviolet Region Based on Boron Nitride Microdisk with Whispering Gallery Mode.

Optical microcavities are known for their strongly enhanced light-matter interactions. Whispering gallery mode (WGM) microresonators have important applications in nonlinear optics, single-mode output, and biosensing. However, there are few studies on resonance modes in the ultraviolet spectrum because most materials with high absorption properties are in the ultraviolet band. In this study, the performance of a microdisk cavity based on boron nitride (BN) was simulated by using the Finite-difference time-domain (FDTD) method. The WGM characteristics of a single BN microdisk with different sizes were obtained, wherein the resonance modes could be regulated from 270 nm to 350 nm; additionally, a single-mode at 301.5 nm is achieved by cascading multiple BN microdisk cavities. Moreover, we found that a BN microdisk with a diameter of 2 μm has a position-independent precise sensitivity for the nanoparticle of 140 nm. This study provides new ideas for optical microcavities to achieve single-mode management and novel coronavirus size screening, such as SARS-CoV-2, in the ultraviolet region.

Circumstellar interaction models for the early bolometric light curve of SN 2023ixf

Type II supernovae (SNe II) show growing evidence of an interaction with circumstellar material (CSM) surrounding their progenitor stars as a consequence of enhanced mass loss during the last years of the progenitor’s life, although the exact mechanism is still unknown. We present an analysis of the progenitor mass-loss history of SN 2023ixf, a nearby SN II showing signs of an interaction. First, we calculated the early-time (< 19 days) bolometric light curve for SN 2023ixf based on the integration of the observed flux covering ultraviolet, optical and near-infrared bands, and black-body extrapolations for the unobserved flux. Our calculations detected the sudden increase to maximum luminosity and temperature, in addition to the subsequent fall, displaying an evident peak. This is the first time that this phase can be precisely estimated for a SN II. We used the early-time bolometric light curve of SN 2023ixf to test the calibrations of bolometric corrections against colours from the literature. In addition, we included the observations of SN 2023ixf into some of the available calibrations to extend their use to earlier epochs. A comparison of the observed bolometric light curve to SN II explosion models with CSM interaction suggests a progenitor mass-loss rate of Ṁ = 3 × 10−3 M⊙ yr−1 confined to 12 000 R⊙ (∼8 × 1014 cm) and a wind acceleration parameter of β = 5. This model reproduces the early bolometric light curve, expansion velocities, and the epoch of disappearance of interacting lines in the spectra. This model indicates that the wind was launched ∼80 yr before the explosion. If the effect of the wind acceleration is not taken into account, the enhanced wind must have developed over the final months to years prior to the SN, which may not be consistent with the lack of outburst detection in pre-explosion images over the last ∼20 yr before explosion.