Methods of objectivization of characteristics of cerebrospinal fluid and examples of their use

BACKGROUND: In modern research standards, a semi-quantitative evaluation scale with crosses is used to characterize turbid cerebrospinal fluid samples, where the absence of turbidity is evaluated as a clear cerebrospinal fluid (a variant of norm), and turbidity is evaluated, depending on the severity, by a different number of crosses. This approach is highly subjective. AIM: Development of a simple objective method for assessment of turbidity of the cerebrospinal fluid. MATERIALS AND METHODS: The optimal wavelength was determined by examination of the optical density of turbid samples of barium sulfate at various wavelengths on Stat Fax photometer (Awarenes, USA). Turbidity was standardized using Shank–Hoagland scale. The reference range was evaluated based on the results of 10 measurements of 10 samples of visually unchanged cerebrospinal fluid. At the same time, the stability and reproducibility of the measured parameters were evaluated. RESULTS: The optimal wavelength diabase is the range emitted by red light filter (λ = 670 nm). Stability of cerebrospinal fluid parameters is preserved for 2 hours after its obtaining. The reference range for normal cerebrospinal fluid samples does not exceed 0.1 units of turbidity on Shank–Hoagland scale. CONCLUSION: The presented methods demonstrate the importance and possibilities of objectivization of characterization of the properties of cerebrospinal fluid with use of the proposed method.

Ultra-Broadband Electromagnetically induced Transparency in Metamaterial Based on Conductive Coupling

In this paper, a structure comprising a horizontal metal strip resonator(SR) and four C-shape ring resonators(CRRs) is proposed, obtaining a broadband electromagnetically induced transparency-like(EIT-like) effect. The SR and CRRs are classified into bright mode and dark mode depending on whether they can be directly excited by the incident electromagnetic wave. The three-level Λ -type system and electric field are used to explain the mechanism of EIT-like effect. Meanwhile, by decreasing the distance between SR and CRRs, a transparency window of 1.4THz with relative bandwidth of 91.93% is observed. It is found that when the bright and dark mode are directly contacted, the EIT window increases rapidly via conductive coupling, which can be explained by the surface current. Our work provides a new method for wide band EIT-like effect, which has certain value in the field of slow light, filter and non-linear optics.

The use of protective red light filter glasses as a m ethod of preventing the development and progression of retinopathy of prematurity, based on the phenomenon of preconditioning photostimulation

Purpose. To study the possible effect of protective red light filter glasses as a method of preventing retinopathy of prematurity, based on the phenomenon of preconditioning photostimulation. Material and methods. For this study, we selected 20 children (40 eyes) from 26.5 to 36 weeks of gestational age and a birth weight of 650 to 2650 grams. All children were divided into 2 groups – the main and control groups of 10 children (20 eyes) each. Results. In the main group of the study, with the use of protective red light filter glasses, the best indicators of the electroretinogram were noted. Conclusions. The use of glasses with red protective light filters-as a method based on the phenomenon of preconditioning photostimulation, is a simple and affordable method of preventing retinopathy of prematurity, which reduces the need for surgical laser treatment and the number of adverse outcomes of this disease. Key words: retinopathy of prematurity, methods of prevention of retinopathy of prematurity.

LIQUID LIGHT FILTER FOR THE VISIBLE SPECTRUM BASED ON HYDROPHILIC SOLUTIONS

The principal possibility of designing a liquid light filter using hydrophilic solutions is considered. Search for hydrophilic solutions with the most uniform light transmission at all wavelengths of the visible spectrum.

The Effect of Using Blue Light Filter Feature on Smartphones with Asthenopia Occurrence

Background: Smartphone users can be found in almost every class society in Indonesia. Excessive use of smartphones and the blue light emitted by smartphones play an important role in causing asthenopia symptoms. Smartphone development companies have developed a blue light filter feature, which is expected to reduce the incidence of Asthenopia symptoms.Objective: To evaluate the Asthenopia questionnaire's comparison results before and after smartphone use with various levels of opacity in the blue light filter.Methods: This study used a quasi-experimental pre-posttest study. The research subjects were students of the Faculty of Medicine, Diponegoro University (n = 30), selected by purposive sampling. In this study, research subjects saw an hour-long smartphone with a predetermined opacity level for the blue light filter, with the same room lighting. Before and after the treatment, the subjects were asked to fill out the Asthenopia questionnaire. Data were analyzed using the Wilcoxon test, Mann Whitney U test, and Kruskal Wallis test.Results: The results of the Asthenopia questionnaire before and after using a smartphone with a blue light filter opacity level of 0% and 100% showed a significant difference in results (p <0.05), and there was no significant difference for the pre-posttest using a smartphone with a blue light filter with 50% opacity level. The comparison results of the Asthenopia questionnaire between smartphone use with the opacity level of the blue light filter 0% and 50% only showed a significant difference in sore/aching eye symptoms. The comparison results of the Asthenopia questionnaire between smartphone use with the opacity level of the blue light filter 50% and 100% only showed a significant difference in sleepy eye symptoms. The comparison results of the Asthenopia questionnaire between smartphone use with the opacity level of the blue light filter 0%, 50%, and 100%, did not show a significant difference.Conclusion: There were no significant differences between the Asthenopia questionnaire results with 0%, 50%, and 100% opacity blue light filters after one hour of smartphone use.

NARROWING OF THE GAAS LED EMISSION SPECTRUM DUE TO THE USE OF THE INP (AG) LIGHT FILTER

АЛ115В LED emission spectrum at currents of 6.3 mA and 56 mA, as well as the emission spectrum using an InP (Ag) light filter at current 56 mA, are studied. A classical approximation of the spontaneous emission spectrum of a straight-band LED is presented (without taking into account the narrowing of the band gap due to the high degree of LED doping). The analytical and experimental widths of the LED band gap are estimated. The transmission spectrum of an InP (Ag) light filter is presented, taking into account reflection losses in the region of fundamental transitions. The spectral dependence (fragment) of the InP absorption coefficient is determined. The error is estimated. It is proposed to use АЛ115В with an InP (Ag) light filter in order to narrow the spectral band of radiation from 53 nm to 34 nm.

Airborne aerosol olfactory deposition contributes to anosmia in COVID-19

Introduction Olfactory dysfunction (OD) affects a majority of COVID-19 patients, is atypical in duration and recovery, and is associated with focal opacification and inflammation of the olfactory epithelium. Given recent increased emphasis on airborne transmission of SARS-CoV-2, the purpose of the present study was to experimentally characterize aerosol dispersion within olfactory epithelium (OE) and respiratory epithelium (RE) in human subjects, to determine if small (sub 5μm) airborne aerosols selectively deposit in the OE. Methods Healthy adult volunteers inhaled fluorescein-labeled nebulized 0.5–5μm airborne aerosol or atomized larger aerosolized droplets (30–100μm). Particulate deposition in the OE and RE was assessed by blue-light filter modified rigid endoscopic evaluation with subsequent image randomization, processing and quantification by a blinded reviewer. Results 0.5–5μm airborne aerosol deposition, as assessed by fluorescence gray value, was significantly higher in the OE than the RE bilaterally, with minimal to no deposition observed in the RE (maximum fluorescence: OE 19.5(IQR 22.5), RE 1(IQR 3.2), p<0.001; average fluorescence: OE 2.3(IQR 4.5), RE 0.1(IQR 0.2), p<0.01). Conversely, larger 30–100μm aerosolized droplet deposition was significantly greater in the RE than the OE (maximum fluorescence: OE 13(IQR 14.3), RE 38(IQR 45.5), p<0.01; average fluorescence: OE 1.9(IQR 2.1), RE 5.9(IQR 5.9), p<0.01). Conclusions Our data experimentally confirm that despite bypassing the majority of the upper airway, small-sized (0.5–5μm) airborne aerosols differentially deposit in significant concentrations within the olfactory epithelium. This provides a compelling aerodynamic mechanism to explain atypical OD in COVID-19.

Preliminary Results: The Impact of Smartphone Use and Short-Wavelength Light during the Evening on Circadian Rhythm, Sleep and Alertness

Smartphone usage strongly increased in the last decade, especially before bedtime. There is growing evidence that short-wavelength light affects hormonal secretion, thermoregulation, sleep and alertness. Whether blue light filters can attenuate these negative effects is still not clear. Therefore, here, we present preliminary data of 14 male participants (21.93 ± 2.17 years), who spent three nights in the sleep laboratory, reading 90 min either on a smartphone (1) with or (2) without a blue light filter, or (3) on printed material before bedtime. Subjective sleepiness was decreased during reading on a smartphone, but no effects were present on evening objective alertness in a GO/NOGO task. Cortisol was elevated in the morning after reading on the smartphone without a filter, which resulted in a reduced cortisol awakening response. Evening melatonin and nightly vasodilation (i.e., distal-proximal skin temperature gradient) were increased after reading on printed material. Early slow wave sleep/activity and objective alertness in the morning were only reduced after reading without a filter. These results indicate that short-wavelength light affects not only circadian rhythm and evening sleepiness but causes further effects on sleep physiology and alertness in the morning. Using a blue light filter in the evening partially reduces these negative effects.