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The thalamus is a key element of sensory transmission in the brain, as it gates and selects sensory streams through a modulation of its internal activity. A preponderant role in these functions is played by its internal activity in the alpha range ([8-14] Hz), but the mechanism underlying this process is not completely understood. In particular, how do thalamocortical connections convey stimulus driven information selectively over the back-ground of thalamic internally generated activity? Here we investigate this issue with a spiking network model of feedforward connectivity between thalamus and primary sensory cortex reproducing the local field potential of both areas. We found that in a feedforward network, thalamic oscillations in the alpha range do not entrain cortical activity for two reasons: (i) alpha range oscillations are weaker in neurons projecting to the cortex, (ii) the gamma resonance dynamics of cortical networks hampers oscillations over the 10-20 Hz range thus weakening alpha range oscillations. This latter mechanism depends on the balance of the strength of thalamocortical connections toward excitatory and inhibitory neurons in the cortex. Our results highlight the relevance of corticothalamic feedback to sustain alpha range oscillations and pave the way toward an integrated understanding of the sensory streams traveling between the periphery and the cortex. J.G.O. was supported by the Spanish Ministry of Science, Innovation and Universities and FEDER (Project PGC2018-101251-B-I00 and Maria de Maeztu Programme, project CEX2018-000792-M ), the Generalitat de Catalunya (Project 2017 SGR 1054), and the ICREA Academia programme. E.C. was supported by the grant “PANACEE” (Prevision and analysis of brain activity in transitions: epilepsy and sleep) of the Regione Toscana – PAR FAS 2007–2013 1.1.a.1.1.2 – B22I14000770002. AM was supported by the Italian Ministry of Research (MIUR, PRIN2017, PROTECTION, Project 20178L7WRS).

Purpose: Determining the total spectral transmission of the porcine crystalline lens at various post mortem intervals. Method: An experimental study conducted in the Department of chemical Pharmacology, Faculty of pharmacy, University of Benin. Twenty pairs of porcine eyes were obtained from an abattoir in Benin City. The crystalline lenses were carefully extracted from the enucleated porcine eyes at various post- mortem intervals (0, 12, 24, 36 and 48hours) and their spectral transmissions were measured using a T80 UV-VIS Spectrophotometer. Measurement at 0 hour was used as a control being the baseline. Result: The result showed a strong negative correlation between increased post mortem intervals and transmission of the crystalline lens for both eyes, as the post-mortem time interval increases, the transmission of long wavelengths (r = -0.992, P = 0.001), mid wavelengths (r = -0.994, P = 0.000) and short wavelengths(r = -0.991, P = 0.001) decreases significantly. It was also observed there was no significant difference (P> 0.05) existed between both eyes in the different wavelength regions with increased post mortem interval. Conclusion: The study shows that time after death has effect on the spectral transmission of crystalline lens which can serve as important information in forensic evaluation. Key words: Post mortem interval, crystalline lens, spectral transmission, spectrophotometer and porcine.

Objective.To examine the value of optical spectral transmission (OST) in detecting joint inflammation in patients with rheumatoid arthritis (RA) and to evaluate whether OST correlates with certain patient characteristics.Methods.OST measurements were performed in the metacarpophalangeal, proximal intraphalangeal, and wrist joints of 168 patients with RA and 114 controls. OST difference between the 2 groups was statistically examined and subsequently controlled for the effect of possible confounding factors. Diagnostic OST performance was tested by receiver-operating characteristics. Moreover, associations of OST with clinical and serological activity markers (patient group), joint ultrasound (US; patient subgroup) and various anthropometric and epidemiologic parameters (patient and control group) were evaluated by Spearman correlation coefficient and a generalized linear statistical adjustment model.Results.OST was significantly higher in the RA group than in the control group, even after adjustment for confounding factors (1.89; 95% CI 0.709–3.070, padj = 0.002). Taking US as a reference, area under the curve for all 1251 joints simultaneously was 0.67 (95% CI 0.631–0.709). In the patient group, correlation and adjustment analyses showed associations of OST with various disease activity markers [28-joint count Disease Activity Score (rho 0.313), swollen joint counts (rho 0.361), C-reactive protein (rho 0.389); all, padj = 0.001], age (rho 0.276, p < 0.001), and osteoarthritis (p = 0.022). Moreover, OST associated with a power Doppler US score (rho 0.442; p = 0.001) and a greyscale US score (rho 0.591; p < 0.001). In both groups males had significantly higher OST values than females and OST associated moderately weakly with body mass index (rho patients 0.316, rho controls 0.24; all, p < 0.001).Conclusion.Patients with RA showed higher OST values in comparison to controls. Moreover, OST associated with clinical, US, and laboratory disease activity markers.

Este artículo se encuentra disponible en la siguiente URL: https://www.mdpi.com/2077-0383/10/19/4490 Este artículo de investigación pertenece a la sección "Ophthalmology". We have assessed the spectral transmittance of the different layers of the human cornea in the ultraviolet (UV), visible, and near-infrared (IR) spectral ranges. Seventy-four corneal sample donors were included in the study. Firstly, the corneal transmittance was measured using a spectrophotometer. Then, all samples were fixed for histopathological analysis, which allowed us to measure the thickness of each corneal layer. Finally, the absorption coefficients of the corneal layers were computed by a linear model reproducing total transmittance. The results show that corneal transmission was almost in unity at the visible and IR ranges but not at the UV range, in which the layer with higher transmission is Descemet’s membrane, whereas the stroma showed the lowest transmittance. Regarding the absorption coefficient, the most absorptive tissue was Bowman’s layer, followed by the endothelium. Variations on transmittance due to changes in the stroma, Bowman’s layer, or Descemet layer were simulated, and important transmission increases were found due to stroma and Bowman changes. To conclude, we have developed a method to measure the transmittance and thickness for each corneal layer. All corneal layers absorb UV light to a greater or lesser extent. The absorption coefficient is higher for Bowman’s layer, while the stroma is the layer with the lowest transmittance due to its thickness. Variations in stroma thickness or changes in the corneal tissue of Bowman’s layer or the endothelium layer due to some pathologies or surgeries could affect, to a greater or lesser degree, the total transmission of the cornea. Thus, obtaining accurate absorption coefficients for different layers would help us to predict and compensate these changes.

Management of light is a crucial task in solar cell design and structure because it increases the path length of the light inside, which in turn increases the probability of electron-hole pair generation. This study addresses the impact of a pyramidal textured structure on spectral transmission in the morphology of silicon. The morphology of silicon wafers was investigated using PC3S spectral transmission software to study the spectral transmission, reflectance, collection probability, mobility, carriers, electric field, velocity, current and surface recombination. Spectral transmission on the front surface with pyramidal texture showed a better transmission percentage than the planar surface. The texture with a depth of 20 µm and base length of 20 µm exhibited good performance in front spectral transmission, spectral reflectance, electric field, velocity, current and surface recombination from the top to the bottom of the sample. The planar surface had more reflectance and lower collection probability than the other pyramidal textured samples due to its low mobility, carriers, electric field, velocity and current but high surface recombination.

The work is devoted to the study and development of a non-toxic and non-hygroscopic system of AgBr - AgI crystals. Crystals of this system are non-toxic, non-hygroscopic, flexible, safe for organic tissues and media, which makes them promising for use in medical technologies. During the development of crystals, the phase diagram of this system was refined. On the basis of the phase diagram, the modes of high-purity raw materials' synthesis and single crystals growth are selected. Using the selected modes, single crystals of various compositions were grown and their optical properties were determined, such as the spectral transmission range and refractive indices at the short-wavelength absorption edge and at the wavelength of the CO 2 laser (10.6 µm), The work results are the basis for the technology development for the production of optical products (infrared fibers, lenses, windows, prisms) for use in laser, endoscopic and diagnostic medicine, including in systems for early diagnosis of cancer.

Current trends in optical fibers will be reviewed such as fibrs with suppressed stimulated Brillouin scattering, silica hollow core optical fibers with extended spectral transmission range, transmission of giant pulses over hollow core fiber lasers, and hollow core fiber gas lasers.

To the Editor: A recent paper by Triantafyllias, et al described that optical spectral transmission (OST) scores, obtained by the HandScan, were significantly higher in male compared to female patients with rheumatoid arthritis (RA) and controls, and an association between OST score and age, BMI, and hand surface area was found.1 The difference in sex that Triantafyllias, et al showed is in line with results of studies performed at our department. We developed and validated a new disease activity index, Disease Activity Score (DAS)-OST, in which tender and swollen joint counts are replaced by the OST score. In the construction of the DAS-OST formula, sex had to be taken into account, because in this study, OST scores were higher in males than in females.2 In addition, by comparing single OST scores to the rheumatologist’s clinical classification into active or inactive RA as reference, different optimal cutoffs for males and females were calculated, again indicating a sex difference. Based on these findings, we investigated whether this difference in sex was also … Address correspondence to Dr. M.M. Verhoeven, Department of Rheumatology & Clinical Immunology G02.228, P.O. Box 85500, 3508GA Utrecht, the Netherlands. Email: m.m.a.verhoeven-15{at}umcutrecht.nl.

To develop and validate a composite rheumatoid arthritis (RA) disease activity index using optical spectral transmission (OST) scores obtained with the HandScan, replacing tender and swollen joint counts.RA patients from a single center routinely undergoing HandScan measurements with at least 1 concurrent OST score and Disease Activity Score in 28 joints (DAS28) were included. Data were extracted from medical records. Linear regression analyses with the DAS28 as the outcome were performed to create a disease activity index (DAS-OST). OST score, erythrocyte sedimentation rate (ESR), and patient global assessment (PtGA) visual analog scale (VAS), sex, age, disease duration, and rheumatoid factor status were evaluated as independent variables. Final models were derived based on the statistical significance of coefficients and model fit. Of the data, two-thirds were used for development and one-third for validation; external validation was performed in a cohort from another center. Agreement between DAS-OST and DAS28 was assessed using the Bland-Altman plot method and intraclass correlation coefficient (ICC). Diagnostic value of the DAS-OST was determined for established definitions of remission, low disease activity (LDA), and high disease activity (HDA).Data of 3,358 observations from 1,505 unique RA patients were extracted. DAS-OST was defined as: -0.44 + OST × 0.03 + male × -0.11 + LN(ESR) × 0.77 + PtGA VAS × 0.03. The ICCs between DAS-OST and DAS28 were 0.88 (95% confidence interval [95% CI] 0.87-0.90) and 0.82 (95% CI 0.75-0.86) and measurement errors were 0.58 and 0.87 in internal and external validation, respectively. Sensitivity for remission, LDA, and HDA was 79%, 91%, and 43%, respectively, and specificity was 92%, 80%, and 96% in external validation.Using the HandScan, RA disease activity can be accurately estimated if combined with ESR, PtGA VAS, and sex into a disease activity index (DAS-OST).

The inverse design of photovoltaic 2D photonic crystals using machine learning will be presented. The technique bypasses calculation of photonic bandstructure in favor of directly computing designer-friendly properties such as spectral transmission.

The importance of this study is to develop handling strategies for human lens studies, aiming at eye health. The aim of this study was to develop a lens holder to facilitate handling lenses having minimal contact with different surfaces while developing experimental protocols. We devised a dissection technique to harvest the lens together with the iris and ciliary body, avoiding any contact with the lens. We also made a specific holder for the lens. Five human lenses were used and preserved in TC199 solution at 4 °C. To test the practicality of the new tool, we weighed the lenses and performed transmission spectroscopy to evaluate the holder’s interference during measurements. The lens holder consists of a pair of anodized plaques with eight pins attached to one of the plaques. The lens is accommodated in the holder by attaching the ciliary muscle to the pins. The holder allows the lens to float inside it, preventing it from deforming, and keeping it intact during the experiment. Overall, the lens holder showed suitable handling in repeated measurement experiments of spectral transmission and daily measurement of the lens mass. In both analyses, the lenses were kept inside the holder without needing to remove them. The novelty of this new lens holder is that it prevents the lens from touching hard surfaces, which can damage the lens. Moreover, the differential of this holder is the possibility of carrying out analyzes on different pieces of equipment without needing to handle the lens.

This study evaluates the spectral transmission of photochromic contact lenses.A custom built photochromic filter transmission testing device (ICS photochromic bench) was developed to measure the spectral transmission of light adaptive filters. The spectral properties of seven contact lenses were measured using the ICS photochromic bench at 23⁰C and 35⁰C in their exposed (darkening) state at time points 0 s, 45 s, 90 s, and 15 min. and their unexposed (fading) state at 45 s, 15 min. and 20 min.. Mixed between and within repeated measures ANOVA (MRM-ANOVAs) and generalized additive modeling (GAMs) were used to compare the effects of temperature and solar exposure time on spectral transmittance of photochromic contact lenses.The mean (±SD) transmission of photochromic contact lenses in the exposed state were 94.7 ± 0.2, 39.1 ± 1.4, 27.0 ± 0.7 and 14.7 ± 1.0, and 93.7 ± 0.9, 38.8 ± 2.4, 30.2 ± 1.8, and 26.1 ± 1.0 at times 0 s, 45 s, 90 s, and 15 min. at 23⁰C and 35⁰C respectively. The mean (±SD) transmission of photochromic contact lenses in the unexposed state were 18.3 ± 1.5, 71.3 ± 2.4, and 80.2 ± 2.4, and 39.1 ± 1.0, 90.6 ± 1.0 and 91.1 ± 0.9 at times 45 s, 15 min. and 20 min. at 23⁰C and 35⁰C respectively. There was a significant decrease in light transmission as solar exposure time increased (GAM, MRM-ANOVA, p0.05). There was a significant effect of temperature and solar exposure time on the photochromic contact lenses (GAM, MRM-ANOVA, p0.05). The differences in the light transmitted by the photochromic contact lenses occurred at time 90 s and 15 min (Tukey HSD, at 90 s and 15 min, p0.05), where contact lenses at a temperature of 35⁰C showed greater light transmission than that at 23⁰C. There were differences in spectral transmittance based on the temperature of the contact lens. Contact lenses at 35⁰C transmitted more light than at 23⁰C at all unexposed times (MRM-ANOVA, p0.05).Spectral transmission of photochromic contact lenses were successfully measured with the ICS photochromic bench. Temperature appears to influence both the activation and deactivation of photochromic contact lenses such that the higher the temperature, the greater the light transmission.

High temperature atlass of spectral lines parameters of the combustion production of energy fuels and their use for modeling the radiation characteristics of the optically active ingredients and radiation heat transfer in high structurally inhomogeneous multicomponent media are considering. The model of the absorption bands to determine the functions of spectral transmission and parameterization according to the results of numerical modelation performed by direct calculation of the fine structure of the emission (absorption) spectra, followed by their numerical integration. The results of the calculations are compared with the data of experimental studies.

As the usage of color images in presenting information via Web sites and smartphone applications increases, the color perception loss may affect the accuracy of the information when it is presented to elderly people. The earlier study considered non-uniform yellowing pigmentation model to mimic the color perception loss of elderly people. Recently, two clinical studies have shown that uniform yellowing pigmentation occurs on the human crystalline lens. In this paper, we propose a mathematical model using uniform yellowing pigmentation to mimic the color perception experienced by elderly people. The uniform yellowing pigmentation is formed using the measured transmittance functions of the LCD display and the spectral transmission factor. The uniform yellowing pigmentation formed is in agreement with the results of the clinical studies. Moreover, subjective evaluation showed that the results from the proposed method are closer to the clinical data and showed improvement when compared to the results from the non-uniform yellowing pigmentation method.

The configuration and the detection of solution concentration are the basic steps of scientific research. Most of solution concentrations can be obtained by indirect method. In this paper, by using the numerical relationship known between the alcohol concentration and refractive index, the relationship between the alcohol concentration and spectral transmission characteristics of the resonance peak can be calculated. The relationship between transmittance and concentration of alcohol solution can be described in a certain nonlinear mathematical expression, which is simple and inversible. Such method provides a novel way to detect alcohol solution concentration and puts forward the expression of the nonlinear correction. The linear relationship that has been using for long time is revised. And it can be reasonable to predict relative parameter that is unknown. This paper provides a new way to reasonable configuration and application for the concentration of solution.

[EN] It is well known that excessive exposure to solar ultraviolet (UV) radiation can have serious adverse effects. Many everyday materials influence the UV radiation received by humans, for example, those used in construction and on the exterior of buildings such as plastics and glass can reduce the UV exposure of persons exposed to solar radiation. In this paper we analyse the spectral transmission of solar radiation of widely used materials using the transmittance parameter. The measurements were performed on clear days, at 8 h and 12 solar hours, in July 2018 (five days) and in January 2019 (three days). The spectral transmittances of these materials and the integrated transmittances in the UVB from 300 nm, UVA, visible (VIS) and near infrared ranges (NIR) were calculated. In summer in the UVB range from 300 nm methacrylate and smoked glass have the highest transmittance values (56%) and polycarbonate present the lowest (30%). In the VIS and NIR ranges methacrylate (95%) and smoked glass (80%) have the highest transmittances and polycarbonate the lowest (45%). In general the 8 h transmittances are higher than those at 12 h and are also higher in winter than summer. For two biological functions (erythemal and DNA-damage) and for the UVB range from 300 nm, the transmittance for most materials (except fibreglass) is in the range 6-14%. The exposure times obtained show that erythemal damage could occur after long exposure to solar radiation through the materials studied, information which should be made available to the general public., The authors wish to thank the Generalitat Valenciana for providing us with access to weather data.

Background Valid assessment of disease activity leads to improvement of long-term outcomes in patients with rheumatoid arthritis (RA) (1). Clinical disease activity assessment tools such as the Disease Activity Score 28 (DAS28) are partially subjective and do not always depict the real inflammatory burden. Ultrasound (US) and Hand-MRI are important diagnostic modalities which can nevertheless be time consuming (US, MRI), expensive (MRI) or usually performed unilaterally (MRI). Thus, further diagnostic tools are needed. Optical spectral transmission (OST) is a new modality able to assess the blood-specific absorption of light transmitted through a tissue promising quantification of inflammation in the finger and wrist joints of RA patients (commercial device: HandScan - Hemics, The Netherlands)(2). Objectives To examine the diagnostic value of OST in detecting inflammation in patients with RA and to evaluate for the first time its relationship with disease activity markers and various anthropometric and epidemiologic patient characteristics. Methods OST-Measurements were performed in 168 RA-patients and 114 healthy controls. The difference between OST in the two groups was statistically examined and subsequently controlled for the effect of possible confounding factors. Moreover, association of OST with clinical, ultrasound and serological RA activity markers was evaluated. Finally, relationship of OST with radiographic joint pathology and various anthropometric and epidemiologic parameters (BMI, hand-size, gender, age) was examined. Results OST was significantly higher in the patients group in comparison to the control group, even after adjustment for the effects of various confounding factors (padj Conclusion OST correlated with serological and clinical disease activity markers as well as with different anthropometric and epidemiological parameters of RA-patients. OST could therefore prove to be a good non-interventional complementary tool to assess RA activity next to well established diagnostic methods such as the US or MRI. References [1] Katchamart W, et al. Systematic monitoring of disease activity using an outcome measure improves outcomes in rheumatoid arthritis. J Rheumatol2010;37:1411–1415. [2] Onna M Van, et al. Assessment of disease activity in patients with rheumatoid arthritis using optical spectral transmission measurements, a non-invasive imaging technique. Ann Rheum Dis2016;75:511–518. Disclosure of Interests Konstantinos Triantafyllias: None declared, Caroline Heller : None declared, Michele De Blasi : None declared, Peter Galle : None declared, Andreas Schwarting Grant/research support from: GSK, Pfizer, AbbVie, Novartis, Roche, Speakers bureau: GSK, Novartis

Background Assessment of disease activity is a critical component of tight-control, treat-to-target treatment strategies of rheumatoid arthritis (RA). Recently, the HandScan has been validated as a novel method for objectively assessing RA disease activity in only 1.5 min, using optical spectral transmission (OST) in hands and wrists. We describe the protocol of a randomized controlled clinical trial (RCT) to investigate whether HandScan-guided treatment aimed at ‘HandScan remission’ (HandScan arm) is at least as effective as and more cost-effective than clinically guided treatment aimed at ACR/EULAR 2011 Boolean remission (DAS arm). Methods/design The study is a multi-center, double-blind, non-inferiority RCT of 18 months duration. Patients ≥ 18 years with newly diagnosed, disease-modifying antirheumatic drug (DMARD)-naïve RA according to the ACR 2010 classification criteria, will be randomized to the DAS arm or the HandScan arm. The efficacy of the arms will be compared by evaluating Health Assessment Questionnaire (HAQ) scores (primary outcome) after 18 months of DMARD therapy, aimed at remission. The equivalence margin in HAQ scores between study arms is 0.2. Secondary outcomes are differences in cost-effectiveness and radiographic joint damage between treatment arms. The non-inferiority sample size calculation to obtain a power of 80% at a one-sided p value of 0.05, with 10% dropouts, resulted in 61 patients per arm. In both arms, DMARD strategy will be intensified monthly according to predefined steps until remission is achieved; in both arms DMARDs and treatment steps are identical. If sustained remission, defined as remission that persists consistently over three consecutive months, is achieved, DMARD therapy will be tapered. Discussion The study protocol and the specifically designed decision-making software application allow for implementation of this RCT. To test a novel method of assessing disease activity and comparing (cost-)effectiveness with the contemporary method in treat-to-target DMARD strategies in early RA patients. Trial registration Dutch Trial Register, NTR6388. Registered on 6 April 2017 (NL50026.041.14). Protocol version 3.0, 19-01-2017. Electronic supplementary material The online version of this article (10.1186/s13063-019-3285-8) contains supplementary material, which is available to authorized users.

Background:Valid assessment of disease activity leads to improvement of long-term outcomes in patients with inflammatory arthritis (1). Optical spectral transmission (OST) is a modern diagnostic tool able to assess the blood-specific absorption of light transmitted through a tissue, promising quantification of inflammation in the finger and wrist joints of patients with rheumatoid arthritis (RA) (commercial device: HandScan – Demcon/Hemics, The Netherlands) (2). Even though an increasing number of studies have evaluated diagnostic value of this new technology in RA patients (2,3), no data exist regarding psoriatic arthritis (PsA).Objectives:To examine for the first time the diagnostic value of OST in detecting inflammation in patients with PsA and to evaluate its relationship with disease activity markers and various epidemiological and anthropometric patient characteristics.Methods:OST-Measurements were performed in a group of PsA patients and a group of healthy controls. The difference between OST in the two groups was statistically examined and relationships of OST with clinical (tender / swollen joint counts, disease activity on a visual analogue scale) and serological disease activity markers were evaluated. Moreover, joint ultrasound (US) examinations were performed in a subgroup of PsA patients and OST associations with a Power Doppler- and a Grey Scale-US score were examined. Finally, relationships of OST with various anthropometric and epidemiologic parameters (BMI, hand-size, gender, age) were assessed.Results:We recruited 49 PsA patients [65.3% female; mean age 53.3 years (± 11.8 SD)] and 114 control subjects [77.2% female; mean age 46 years (± 12.8 SD)]. OST was statistically significantly higher in the patient group, compared to the control group [14.95 (12.04 - 17.18, IQR) vs. 10.31 (7.84 – 13.79, IQR); pConclusion:This is the first report of a possible diagnostic value of OST in patients with PsA. OST correlated with ultrasound and serological activity markers and may thus prove to be a useful tool of disease activity assessment, next to well established diagnostic modalities, such as the joint US. Correlations of OST with patient characteristics implicate the need to take also anthropometric and epidemiological patient characteristics into account when interprenting OST results in order to avoid confounding.References:[1]Katchamart W, et al. Systematic monitoring of disease activity using an outcome measure improves outcomes in rheumatoid arthritis. J Rheumatol 2010;37:1411–1415.[2]Triantafyllias, et al. Diagnostic value of optical spectral transmission in rheumatoid arthritis: associations with clinical characteristics and comparison with joint ultrasonography. J Rheumatol 2020 1;47(9):1314-1322.[3]Onna M Van, et al. Assessment of disease activity in patients with rheumatoid arthritis using optical spectral transmission measurements, a non-invasive imaging technique. Ann Rheum Dis 2016;75:511–518.Disclosure of Interests:Konstantinos Triantafyllias Speakers bureau: Pfizer, Novartis, Janssen, Chugai, Stefanie Liverakos: None declared, Claudia Noack: None declared, Andreas Schwarting: None declared

To the Editor: We have read with great interest the letter of Verhoeven, et al ,1 referring to our recent publication on the diagnostic value of optical spectral transmission (OST) in rheumatoid arthritis (RA).2 In our work we had described for the first time, to our knowledge, that OST values could be influenced not only by disease-associated factors (i.e., inflammatory activity) but also by patient-associated characteristics, such as sex, BMI, and age. …

In this article, we propose an approach to measure solution concentrations by using photonic crystal cavities. Based on the experimental data, the refractive index of a NaCl solution is proportional to the concentration. Filling the proposed photonic crystal cavity with a NaCl solution, we calculate the spectral transmission using the transfer matrix method. We found that the cavity transmittance was proportional to the refractive index of the NaCl solution, and thus we obtained a linear relationship between cavity transmittance and the concentration of the NaCl solution. The formula was found by fitting the simulation results with experimental data. Such a formula can be applied to the measurement of an unknown concentration of NaCl solution utilizing a photonic crystal cavity.

In an attempt to understand the influence of basic structural parameters of fabrics on thermal protection and comfort, present study mainly focuses on analyzing effect of fabric weaving pattern and fabric weight. Fabric samples of three basic weaving patterns (plain, twill, and satin) and three different weights were prepared. Air permeability of the developed fabric samples was measured. Thermal protective performance of fabrics against radiant heat and flame exposures of two different intensities were measured. Spectral transmission behavior of fabrics was also studied. It was observed that for same fabric weight, protective performance and air permeability of satin woven fabrics were better as compared to the fabrics of other patterns. Protective performance increased and air permeability decreased as fabric weight increased for each type of woven structure included in this study. A new structural parameter is proposed which primarily influences the protective performance of fabrics exposed to ...

Spectral systems with an MKhK-6 cryogenic, high-throughput, multipass gas cell for studying the absorption spectra of gaseous media with high spectral resolution in the 0.1–6 μm range at pressures of 100 to 5·106 Pa and temperatures of 180–300 K are discussed. Their use in measurements of spectral absorption coefficients, temperature dependences of the spectral transmission function, and parameters of spectral absorption lines is examined.

Background:Optical spectral transmission imaging (OST) is a new imaging method that measures inflammation in the hands of rheumatoid arthritis (RA) patients. OST might be used to assess disease activity instead of disease activity score 28 (DAS28) or ultrasonography (US). The advantage of OST is that it is fast and not operator dependent. Up to now OST has only been investigated cross-sectionally and it is unknown if and to what extent OST can detect inflammatory changes due to anti-inflammatory treatment for RA.Objectives:To compare OST measurements before and after 1 month of biological treatment for RA and to compare these OST changes with changes on US and disease activity.Methods:The HandScan device from Hemics, the Netherlands, was used to measure OST scores for 13 RA patients before and after 1 month of anti-inflammatory therapy. Treatment included tumor necrosis factor inhibitor (n=10), tocilizumab (n=2) and tofacitinib (n=1). OST scores range from 0-66 (one score for both hands) and are based on bilateral wrist, MCP and PIP joints. US was performed in the same joints as OST and semi-quantitatively scored on a scale of 0-3 for grey-scale (GS) synovitis and power Doppler (PD) signal. Joint scores of GS synovitis or PD were summed, resulting is a total GS synovitis score and a total PD score, both also ranging from 0-66. Furthermore, tender joint count 28 (TJC28), swollen joint count 28 (SJC28), DAS28, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were determined. Response to therapy was defined as achieving the minimal clinically interesting improvement of DAS28 (DAS28 difference after 1 month > -1) as proposed by Ward et al. [1]Results:Baseline OST was 17.73 ± 6.10 and this significantly decreased to 16.01 ± 6.68 (difference -1.71, 95%CI 0.05-3.38, p=0.045) after 1 month of therapy. This decrease was only present in patients who responded to therapy (n=8; OST decreased from 17.24 ± 5.98 to 14.26 ± 5.65, p=0.01) and not in non-responders (n=5; OST increased from 18.52 ± 6.90 to 18.83 ± 7.87, p=0.03).In the total group, also DAS28 (difference -1.59, 95%CI 0.74-2.45, p=0.002), SJC28 (difference 4.62, 95%CI 1.50-7.73, p=0.007), ESR (Wilcoxon Rank p=0.008) and CRP (Wilcoxon Rank p=0.03) significantly decreased after 1 month of therapy, but TJC28 did not (difference 2.62, 95%CI -2.7-7.91, p=0.30).OST change after 1 month of therapy significantly correlated with TCJ28 change (table 1). For GS synovitis the correlation coefficient nearly reached statistical significance. Changes in all other disease activity parameters were not correlated with OST change.Table 1.Correlation of change in OST measurement with change in disease activity after 1 months of anti-inflammatory therapySpearman rp-valueTotal GS synovitis0.540.06Total PD0.220.47DAS280.350.25SJC280.290.33TJC280.630.02ESR-0.420.15CRP-0.230.45Conclusion:OST scores significantly decreased after 1 month of anti-inflammatory therapy and only in the RA group that responded well to this therapy. This indicates that OST is capable of detecting therapy induced inflammatory changes in the hands of RA patients. Larger studies are needed to further assess the monitoring value of OST for therapy efficacy in RA patients.References:[1]Ward et al. 2015 Clinically important changes in individual and composite measures of rheumatoid arthritis activity: thresholds applicable in clinical trials. Ann Rheum Dis 74(9): p. 1691-6.Disclosure of Interests:Annelies Blanken: None declared, C.J. van der Laken: None declared, Michael Nurmohamed Grant/research support from: Not related to this research, Consultant of: Not related to this research, Speakers bureau: Not related to this research

ObjectiveTo determine whether optical spectral transmission (OST) can be used to assess synovitis in hand and wrist joints of patients with hand osteoarthritis (OA).DesignHand and wrist joints of 47 primary hand OA patients with at least one clinically inflamed hand or wrist joint were assessed for synovitis by OST and ultrasound (US). Associations between standardized OST and US synovitis were studied in linear mixed effects models, across all joint types together and individually for wrist, proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints, and were adjusted for OA features that showed associations with US synovitis. Diagnostic performance was determined using receiver operator characteristic (ROC) curves analysis, with US as reference standard.ResultsAltogether, 6.7% of joints showed US synovitis. Statistically significant associations between OST scores and US synovitis were found for all joints combined (Δ0.37SD, pConclusionsOST scores and US synovitis are statistically significantly associated, independent of osteophytes and dorsal vascularity. At this stage, OST performs fair in the assessment of synovitis in PIP joints of hand OA patients.

Este artículo se ha publicado de forma definitiva en: http://www.scielo.br/pdf/abo/v82n1/0004-2749-abo-82-01-0056.pdf Purpose: The porcine eye is frequently used as a research model. This paper analyzes the effect of different storage methods on the transparency of pig crystalline lens. Methods: A spectral transmission curve (from 220 to 780 nm) for the crystalline lens was determined experimentally after storage in different conditions: saline solution, formalin, castor oil, and freezing at -80°C. The total transmission in the visible spectrum, which was used as an index of transparency, was calculated from these curves. For comparative purposes, fresh lenses were evaluated and used as controls. Results: Storing the porcine crystalline lens in saline solution or castor oil resulted in a transparency loss of approximately 10% after 24 h and storage in formalin resulted in a loss of nearly 30%. Storage by freezing at -80°C for 4 weeks maintained the transparency of the crystalline lens; the spectral transmission measured immediately after defrosting at room temperature coincided exactly with that of the freshly extracted lens. Conclusions: The transparency of porcine crystalline lens is affected by the storage method. The visible spectrum is the most affected, evidenced by the effect on the transparency and consequently the amount of light transmitted. The results show that freezing at -80°C maintains the transparency of the crystalline lens for at least 4 weeks. Olho de porco é frequentemente usado como modelos de pesquisa. Este estudo analisa o efeito de diferentes métodos de armazenamento na preservação da transparência do cristalino de porco. Métodos: Uma curva de transmissão espectral (de 220 até 780 nm) para o cristalino foi experimentalmente determinada após armazenamento em diferentes condições: solução salina, formol, óleo de mamona e congelamento a -80°C. Transmissão total do espectro visível, que foi usada como um índice de transparência foi calculada a partir dessas curvas. Para fins comparativos, lentes frescas foram avaliadas e usadas como controles. Resultados: O armazenamento do cristalino suíno em solução salina ou óleo de mamona resultou uma perda de transparência de aproximadamente 10% após 24 h e o armazenamento em formol resultou uma perda de quase 30%. O armazenamento por congelamento a -80°C durante 4 semanas manteve a transparência do cristalino; a transmissão espectral medida imediatamente após o descongelamento à temperatura ambiente coincidiu exatamente com a da lente extraída recentemente. Conclusão: A transparência do cristalino suíno é afetada pelo método de armazenamento. O espectro visível é o mais afetado, evidenciado pelo efeito sobre a transparência e consequentemente a quantidade de luz transmitida. Os resultados mostram que o congelamento a -80°C mantém a transparência do cristalino suíno por pelo menos 4 semanas.

Background The handscan is a new technologic device which uses diffuse optical transmission in combination with blood flow modulation. It is a non-invasive measurement of joint inflammation potentially more sensitive than the clinical evaluation of the joints by a rheumatologist[.1 However, more clinical data is necessary before this new device can be implemented in the daily clinical practice. Objectives This study investigates the additional value of the handscan in decision making in the daily practice for patients with rheumatoid arthritis. Methods At our outpatient clinic we started a registry for rheumatoid arthritis patients with a disease duration of at least two years. During this period, a handscan will be made for all patients before every regular visit. Both the patient and the treating rheumatologist will be blinded to the handscan outcome. Primary outcome is the association between DAS28 score and the total optical score (TOS) of the handscan per visit. Results The study started in December 2017, until now 100 patients are included. The mean age was 61.1 years, the mean disease duration at time of inclusion 11.2 years, 67% were rheumatoid factor positive, 51% were anti-CCP positive. In figure 1 we show the association between DAS28 and the TOS in a linear model. Currently there is no validated cut off point for the TOS (negative or positive score for inflammation). In our group of 100 patients the median TOS was 10, the most discriminating TOS was found to be 17 using chi-square test as depicted in table 1. Conclusions In this preliminary evaluation of the first 100 patients, we observed a limited positive correlation between the total optical score of the handscan and the DAS28. The TOS above 17 associates with moderate to severe disease activity. The definite clinical value of the handscan needs to be determined with longitudinal measurements and it’s predictive value versus the DAS28. The ongoing current registry aims to answer these questions. Reference [1] Van Onna M, Ten Cate DF, Tsoi KL, et al. Assessment of disease activity in patients with rheumatoid arthritis using optical spectral transmission measurements, a non-invasive imaging technique. Ann Rheum Dis2016;75:511–8. doi:10.1136/annrheumdis-2015-207315 Disclosure of Interest A. Al Hasan Grant/research support from: this reserach is supported by an unrestricted grant from Stichting De Friesland, R. Bos Grant/research support from: this reserach is supported by an unrestricted grant from Stichting De Friesland, N. Veeger: None declared, D. Zhang: None declared, L. Hendriks: None declared, F. Wink: None declared, A. Schilder: None declared, F. Reimann: None declared, K. Bergsma: None declared

This letter proposes a new method for designing photonic crystal (PhC) filters. The method is proposed while designing novel superdefect PhC filters with three and five ellipse-shaped rods. The main idea of the method is to formulate the optical filter design problem as an optimization problem and to solve it by single-objective optimization techniques. This method bypasses discovering the complex relationship between the output spectral transmission performance and the radii of rods. The results demonstrate the merits of the method in facilitating the design process of the PhC filters and finding high-performance designs.

We demonstrate a new method of use of acousto-optic filters consisting in adaptive modifying of the broadband arbitrary spectral transmission function of the device. The essence of the method consists in tailoring a complex-valued spectral transmission function of the acousto-optic filter and further calculating RF waveform that provides the desired spectrum. The performance of the method is experimentally demonstrated both for coherent and incoherent light.

In the present paper we present ways to modulate the periodic transmission peaks arising in disordered one dimensional photonic structures with hundreds of layers. Disordered structures in which the optical length nd (n is the refractive index and d the layer thickness) is the same for each layer show regular peaks in their transmission spectra. A proper variation of the optical length of the layers leads to a splitting of the transmission peaks. Notably, the variation of the occurrence of high and low refractive index layers, gives a tool to tune also the width of the peaks. These results are of highest interest for optical application, such as light filtering, where the manifold of parameters allows a precise design of the spectral transmission ranges., Comment: 5 pages, 3 figures

The results of the studies of the spectral characteristics of terrestrial solar radiation carried out based on the calculation model for an index dependence of spectral air mass transmission coefficients relative to the standard solar radiation АМ-1.5 are presented for different air mass values. Spectral transmission coefficients for standard air mass АМ-1.5 relative to extraterrestrial solar radiation AM-0 are obtained by comparing the respective spectral intensities from the published literature. During the theoretical calculations, the limiting value of the air mass (for the solar disk near the horizon) is taken to be large by a factor of 36 than for air mass AM-1.

PURPOSE The aim of this study was to evaluate the clarity of gamma-irradiated sterile corneal donor lenticules. METHODS Broadband UV, visible, and near-infrared (200-850 nm) light transmission was measured through gamma-irradiated, sterile partial-thickness, and full-thickness donor lenticules and fresh corneal tissues and compared with standard acrylic intraocular lens (IOL) implants using a conventional spectrophotometer technique. RESULTS All tissues had high light transmission (≥ 90%) in the visible and near-infrared regions and very low (

We present a technique and algorithm for measuring the phase retardation of a wave plate based on spectral transmission curve. Through accurately extracting the intersection points' wavelengths from the spectral transmission curve, the effective phase retardation, absolute phase retardation, order, and physical thickness of the wave plate can be measured simultaneously in a wide spectral range. Experimental results show that the proposed technique has many advantages, such as higher data utilization, simpler extraction algorithm, and no strict requirement for the directions of transmission axes of the polarizer and analyzer, and the fast axis of the wave plate.

Emission and absorption spectra of water vapor are measured and analyzed for temperatures 350–2500 K in the spectral range 0.57–25 μm. Based on the developed mathematical model of radiative transfer, the parameters of spectral transmission functions of Н2О vapors are obtained at different temperatures. Practical application of the obtained radiative characteristics is considered for solving problems of radiative heat exchange in high-temperature media and designing optoelectronic systems intended for monitoring of aero carriers.