Light-emitting Diode Radiation Research Articles

Негативний диференціальний опір і спектральні характеристики вихідних та опромінених електронами (з Е = 2 МеВ) світлодіодів GaAs1-xPx

The electrophysical and radiation characteristics of the original and irradiated electrons with E = 2 MeV GaAsP light emitting diodes were studied. The results of measurements of current-current characteristics in the range of 77 - 300 K are given. In the range of 180 - 77 K, a region of negative differential resistance was detected. The main characteristic parameters of light emitting diodes radiation are determined. The consequences of the effect of radiation defects on the emissivity and quantum yield of the studied structures are discussed.

Quasi van der Waals Epitaxy of Single Crystalline GaN on Amorphous SiO2/Si(100) for Monolithic Optoelectronic Integration.

The realization of high quality (0001) GaN on Si(100) is paramount importance for the monolithic integration of Si-based integrated circuits and GaN-enabled optoelectronic devices. Nevertheless, thorny issues including large thermal mismatch and distinct crystal symmetries typically bring about uncontrollable polycrystalline GaN formation with considerable surface roughness on standard Si(100). Here a breakthrough of high-quality single-crystalline GaN film on polycrystalline SiO2/Si(100) is presented by quasi van der Waals epitaxy and fabricate the monolithically integrated photonic chips. The in-plane orientation of epilayer is aligned throughout a slip and rotation of high density AlN nuclei due to weak interfacial forces, while the out-of-plane orientation of GaN can be guided by multi-step growth on transfer-free graphene. For the first time, the monolithic integration of light-emitting diode (LED) and photodetector (PD) devices are accomplished on CMOS-compatible SiO2/Si(100). Remarkably, the self-powered PD affords a rapid response below 250µs under adjacent LED radiation, demonstrating the responsivity and detectivity of 2.01×105 A/W and 4.64×1013Jones, respectively. This work breaks a bottleneck of synthesizing large area single-crystal GaN on Si(100), which is anticipated to motivate the disruptive developments in Si-integrated optoelectronic devices.

Germicidal Efficiency of 272 nm LED in Relation to the Hospital Strain of Klebsiella Pneumoniae

Relevance. Currently, the use of ultraviolet (UV) radiation for the disinfection of objects and the treatment for infectious diseases is considered as a promising alternative to chemical biocides and antibiotics. Shortwave — UV-C and UV-B -light emitting diodes (LED) are a relatively new type of UV radiation sources and potentially able to meet the requirements of current medical technologies. However, their possibilities for the treatment of wounds and infectious diseases have not been practically researched to date, which determines the relevance of experiments aimed at studying the biocidal and therapeutic properties of shortwavelength UV LEDs.Purpose. OF STUDY To evaluate the bactericidal efficacy of 272 nm LED radiation against hospital strains of Klebsiella pneumoniae bacteria characterized by multidrug resistance.Materials and Methods. The studies were carried out with an experimental sample of the LED apparatus for UV irradiation. In the irradiator of the device, 5 LEDs are installed with a maximum radiation at a wavelength of 272 nm and a total electrical power of 10 watts. The UV radiation dose achieved in one irradiation session (12 seconds) at a distance of 10 cm from the irradiator was 8 mJ/cm2 . In the experiments, a hospital strain of the bacterium Klebsiella pneumoniae, isolated from the patient’s blood, was used. The strain was characterized by multidrug resistance. A daily culture suspension of K. pneumoniae with a concentration of 108 CFU/ml in a volume of 100 µl was transferred into a Petri dish with a diameter of 9 cm with meat-peptone agar and evenly distributed over a surface with a diameter of 8 cm. Petri dishes were irradiated from a distance of 10 cm from the irradiator. The change in the dose of UV irradiation from 4 to 80 mJ/cm2 was carried out by varying the exposure time. Studies were carried out in 4 repetitions at each dose. After irradiation, the experimental and control (without irradiation) Petri dishes were placed in a thermostat at 37ºC for 24 hours, then the grown colonies were counted. A total of 60 experiments were carried out.Results. As a result of the research, it was shown that the LED device based on five 272 nm diodes provides deep and prompt disinfection of the surface from hospital strains of K. pneumoniae bacteria characterized by multidrug resistance. A dose of UV radiation of 8 mJ/cm2 reduces surface contamination with K. pneumoniae bacteria by more than a million times (decontamination efficiency over 99.9999%). At doses less than 10 mJ/cm2 , the efficiency of the 272 nm LED device in terms of inactivation of K. pneumoniae bacteria is 3–4 times higher than the bactericidal efficiency of mercury lamps.Conclusion.The prospects of using UV devices based on LEDs with a maximum radiation at a wavelength of 272 nm in systems for the operational disinfection of massively contaminated surfaces, potentially including wound surfaces, have been shown.

Calculation and Selection of Spectral Characteristics of Radiation of LED Luminaires for Operation Rooms

Many researchers considered improvement of colour discrimination an important factor of surgery illumination, but none of them provided data on colour contrast estimation. The article describes the results of an extensive search of spectrum that are the most preferable for application in surgery equipment using selected light emitting diodes (LED) of different types. The search was not also based on the qualitative characteristics recommended by the standard, but also on a previously non-considered parameter: colour contrast between human tissues K estimated in uniform-chromaticity systems. The programme developed in MATLAB environment allows to model the cumulative spectrum of a LED light source, to determine the proportions of LED radiation or crystals in LED providing the maximum value of LED general colour rendering index Ra at the set correlated colour temperature or the maximum value of averaged K in uniform-chromaticity systems both in presence of the limited Ra value of 85 and if there are no limitations. Such options of spectrum search allowed to evaluate the probability of K change and its maximum, as well as to identify three possible operating modes of surgery equipment when using the said LEDs. The first of them is following the existing recommendations for Ra with possible insignificant change of K, the second one is the priority of K assuming violation of the Ra recommendations to increase K, and the third option assumes switching between the modes if necessary. LED spectra are selected for such different modes. Other colour rendering indexes are also estimated, and the authors recommend using the new standard TM‑30–15 for standardisation of the colour rendering quality of light sources used in surgery luminaires. It is based on 99 samples and some of the tests have reflective properties close to those of human tissues.

Choosing a Method for Approximating the Spectral Distribution of Colour LEDs and Comparing their Parameters and Characteristics in Nominal Mode

New technologies and new light sources make it possible to create fundamentally new approaches in the design and construction of lighting devices. Light emitting diodes (LEDs) are a relatively new, promising and energy-efficient light source with a few unique properties: long lifetime, high luminous efficiency, aesthetics, environmental friendliness, reliability, high durability, and possibility to create a variety of spectra easily. During the lighting devices development, it is convenient to use mathematical approximations of the spectral distributions of the used LEDs in the composition of the product to calculate the final spectrum of the device in the visible range. These calculation methods are particularly interesting in architectural lighting. They are also applicable to the development of modern LED greenhouse irradiators. The article considers two main methods for approximating the emission spectra of colour LEDs: via symmetric and asymmetric distribution. The spectral distributions of four main types of LEDs that are used in the lighting devices design based on colour LEDs were measured in a wide range of currents from 100 mA to 1000 mA: red, amber, green, and blue. The results were also compared with a model that considers the two-dimensional density of states and potential fluctuations in the active region of the heterostructure of LED. Based on the carried-out measurements and calculations, the optimal approximation method via the asymmetric spectral distribution of LED radiation was determined.

Short-Wave Ultraviolet-Light-Based Disinfection of Surface Environment Using Light-Emitting Diodes: A New Approach to Prevent Health-Care-Associated Infections

Ultraviolet (UV)-C irradiation is a promising method for microbial eradication on surfaces. Major developments have taken place in UV-C light-emitting diodes (LEDs) technology. In this study, we examined the suitability of UV-C LED-based surface disinfection in hospitals. We tested the efficacy of UV-C LED surface treatment on different microorganisms dried on a carrier surface or in a liquid solution. The influences of soiling, shading, surface material, radiation wavelength, microbial load and species on the disinfection performance were investigated. UV-C LED caused a reduction of >5 log10 levels of E. coli, S. aureus and C. albicans, whereas 3 log10 reduction was observed for G. stearothermophilus spores. The components of the medium led to a reduced UV-C LED efficiency compared to buffered solutions. We observed that the microbial load and the roughness of the carrier surface had a major influence on the UV-C LED disinfection efficiencies, whereas shading had no impact on inactivation. This study showed that UV-C is suitable for surface disinfection, but only under certain conditions. We showed that the main factors influencing microbial inactivation through UV-C light (e.g., intrinsic and extrinsic factors) had a similar impact when using a UV-C LED radiation source compared to a conventional UV-C lamp. However, the potential of LEDs is contributed by their adjustable wavelength and customizable geometry for the decontamination of medical devices and surfaces, and thereby their ability to overcome shading effects.

Effect of Light Emitting Diodes (LED) Exposure on Vitreous Metabolites-Rodent Study.

The exposure to blue and white Light emitting diodes (LED) light leads to damage in the visual system with short-term LED light exposure. Chronic exposure, adaptive responses to light, and self-protective mechanisms against LED light exposures need to be explored, and it would be essential to understand the repercussions of LED radiation on vitreous metabolites. A total of 24 male Wistar rats were used in this study, divided into four groups (n = 6 in each group). Three experimental groups of rats were exposed to either blue, white, or yellow LED light for 90 days (12:12 light-dark cycle routine) with uniform illumination (450-500 lux). Standard lab settings were used to maintain control rats. Vitreous fluids were subjected to untargeted metabolomics analysis using liquid chromatography-mass spectrometry (LC/MS). PLS-DA analysis indicated significant the separation of m metabolites among groups, suggesting that LED exposure induces metabolic reprogramming in the vitreous. Amino acids and their modifications showed significant alterations among groups which included D-alanine, D-serine (p < 0.05), lysine (p < 0.001), aspartate (p = 0.0068), glutathione (p = 0.0263), taurine (p = 0.007), and hypotaurine. In chronic light exposure, the self-protective or reworking system could be depleted, which may decrease the ability to compensate for the defending mechanism. This might fail to maintain the metabolomic structural integrity of the vitreous metabolites.

The Effect of The Blue-Violet Light Emitting Diode (Led) Irradiation on the Bleeding and Pain Following Tooth Extraction.

Tooth extraction is one of the most common oral surgeries carried out daily in dental clinics. Bleeding and pain are considered common sequelae after tooth extraction, which are considered a major concern. The purpose of this study was to evaluate the effectiveness of the irradiation on the extraction socket with a blue-violet light-emitting diode (LED) on the hemostasis and the pain.The study was designed as a randomized prospective split-mouth clinical study in which 82 tooth extractions were performed on 31 patients who required bilaterally paired tooth extractions. The side impacted by LED radiation until the bleeding stopped was the study group (left side), whereas the other side where the bleeding stopped without intervention was the control group (right side). The duration of bleeding time was measured and compared. The pain level was assessed postoperatively using the numeric rating scale and total analgesic dosages.Results indicate that in the study group there was a reduction in postextraction bleeding time as compared with the control group. The mean bleeding time was (26.71 seconds) and (291.95 seconds), respectively. It was statistically significant ( P = 0.000). Regarding the effect of LEDs on pain, the result shows no difference in the pain level between the 2 groups, which means LEDs have a nonsignificant effect on pain.The blue-violet LED reduces the bleeding time of the extracted socket after tooth extraction, and prevents postoperative oozing, but has no effect on the reduction of postoperative pain. LED therapy has no side effects.

Irradiation with 590-nm yellow light-emitting diode light attenuates oxidative stress and modulates UVB-induced change of dermal fibroblasts.

Recently, light-emitting diode (LED)-based devices have emerged as effective and safe tools for the treatment of photoaged skin. However, few studies have been conducted to elucidate the underlying mechanism behind the effect on photoageing of LED light. In this study, we induced photoageing of human dermal fibroblasts (HDFs) with Ultraviolet B (UVB) irradiation and evaluated the ability of 590-nm LED radiation to induce recovery from oxidative stress, restore collagen formation and regulate inflammatory changes. Photoageing was induced in cultured human dermal fibroblasts (HDFs) using UVB irradiation of 50mJ/cm2 . Then, the photoaged HDFs were irradiated with LED using a custom-built 590-nm LED device which emits light with an intensity of 38mW/cm2 (irradiated for 900s with 34.2J/cm2 of total energy). LED irradiation significantly attenuated UVB-induced reactive oxygen species generation and UVB-induced phosphorylation of JNK, c-Fos and c-Jun. In addition, the procollagen levels were recovered significantly, and MMP-9 levels were significantly suppressed after LED irradiation. The UVB-induced phosphorylation levels of NF-κB and pro-inflammatory enzyme COX-2 also significantly decreased. Our results suggest that 590-nm yellow light irradiation may be an effective and safe anti-oxidative and anti-inflammatory treatment modality for photoaged skin.

Effective interference mitigation scheme for multi-LED-based mobile optical camera communication.

Recently, optical camera communication (OCC) based on light-emitting diodes (LEDs) and complementary metal oxide semiconductor (CMOS) image sensors has received extensive attention due to its low cost and high flexibility. However, considering that the location of the user with a CMOS image sensor changes frequently, multi-LEDs are required to achieve seamless communication. In the paper, to mitigate random interchannel interference in overlapping areas of LED radiation, an effective identification recognition and sorting-based column selection are proposed. Meanwhile, to alleviate the distortion of bright and dark stripes caused by overlapping exposure time and user movement, an improved sampling scheme based on length estimation is proposed and experimentally demonstrated in a multi-LED-based mobile OCC system. Moreover, by varying the overlap rate of the adjacent LEDs' radiation area and the moving speed of the user, respectively, the performance of the system is investigated. The experimental results show that, the bit error rate (BER) performance of the system decreases slightly with the increasing of moving speed, but it is lower than the hard-decision forward error code rate limit. In addition, at the overlap rate of the LED radiation area of 4.3% and the moving speed of 80 cm/s, the BER is close to 10-6 using the proposed scheme.

Proteomics of Streptococcus mutans to Reveal the Antibiofilm Formation Mechanism of Ag/ZnO Nanocomposites with Light-Emitting Diode Radiation.

IntroductionAs a biofilm-associated disease, dental caries benefits from nanoparticle (NP)-based therapies. Streptococcus mutans (S. mutans) is a primary aetiologic agent for dental caries development. We successfully applied a synergistic therapy of Ag/ZnO nanocomposites combined with light-emitting diode (LED) radiation to inhibit S. mutans biofilms. However, the antibiofilm mechanism has not been fully elucidated, and little is known about the biofilm formation ability of bacteria that survive NP-based therapies.MethodsThis study explored the antibiofilm formation mechanism of this synergistic therapy by an integrated approach based upon proteomics.ResultsSynergistic therapy killed 99.8% of bacteria, while the biofilm formation ability of 0.2% surviving bacteria was inhibited. The proteomic responses of S. mutans to synergistic therapy were comprehensively characterized to unveil the mechanism of bacterial death and biofilm formation inhibition of the surviving bacteria. In total, 55 differentially expressed proteins (12 upregulated and 43 downregulated) were recorded. The bioinformatic analysis demonstrated that cellular integrity damage and regulated expression of structure-associated proteins were the main reasons for bacterial death. In addition, the proteomic study indicated the potential inhibition of metabolism in surviving bacteria and provided a biofilm-related network consisting of 17 differentially expressed proteins, explaining the multiantibiofilm formation actions. Finally, we reported and verified the inhibitory effects of synergistic therapy on sucrose metabolism and D-alanine metabolism, which disturbed the biofilm formation of surviving bacteria.ConclusionOur findings demonstrated that synergistic therapy killed most bacteria and inhibited the surviving bacteria from forming biofilms. Furthermore, the antibiofilm formation mechanism was revealed by proteomics analysis of S. mutans after synergistic therapy and subsequent metabolic studies. Our success may provide a showcase to explore the antibiofilm formation mechanism of NP-based therapies using proteomic studies.

Photobiostimulation of Chlorella sorokiniana using light emitting diodes (LEDs) for increasing lipid and biodiesel production

At present, the major body of research is focused on weaning the world from fossil fuels. The problem is that the world is running out of fossil fuel. Therefore, an alternative source must be identified. The biofuels are promising alternatives. In the case of petrodiesel, a promising alternative is biodiesel production from algae. The ability of microalgae to generate large quantities of lipids with a fast growth rate made them superior biodiesel producers. Using light-emitting diodes (LEDs) as an energy source in microalgal cultivation was recently increased owing to its large spectrum, endurance, and low-energy utilization. Changes in cultivation conditions, limited capabilities of harvesting light, and self-shading of microalgae were the most important problems. Therefore, the photobiostimulation of algae using LEDs radiation led to an increase in algal growth rate which results in increased lipid production. This research investigated the influence of monochromatic LEDs on the growth of Chlorella sorokiniana microalga. At the first phase, microalgae growth and algal biomass significantly increased under red LEDs [2.3 g/L], blue LEDs [1.8 g/L], green LEDs [0.7 g/L], and white LEDs (0.6) g/L as a control, respectively. At the second phase, microalgal growth and algal biomass significantly increased under red LEDs [2.9 g/L], blue LEDs 2.3 g/L, and white LEDs (1.5) g/L as a control, respectively. The percentage of extracted oil (%) or the yield of extracted oil of microalgae was 10.38 % (white LEDs), 16.94 % (blue LEDs), and 15.55 % (red LEDs) respectively. It was concluded that the photobiostimulation of algae using LEDs led to the enhanced weight of algal biomass, therefore increased of lipids and biodiesel production. The red LEDs were the best one in terms of increasing the weight of algal biomass. The blue LEDs were the best one in terms of increasing the percentage of extracted oil. However, the green LEDs were not effective.

В Л И Я Н И Е Ф Д Т С И С П О Л Ь З О В А Н И Е М ПРЕПАРАТА ХЛОРИНА- Е 6 (Х- Е 6) Н А Ж И З Н Е С П О С О Б Н О С Т Ь И Ф У Н К Ц И О Н А

We expiremented with mice inoculated with intramuscularly embryocarcinoma and registered functional condition of T-lymphocytic link of cells of bone brain and spleen to the index of spontaneous and stimulated by mitogen (PHA) proliferation. Intact animals and the ones which we introduced with Chlorine e6 and keep in dark conditions have revealed the zero level of the indexes. But the animals being introduced with Chlorine e6 and activated with laser and light-emitting diode radiation have been notable for the index of mitogen (PHA) stimulation. It was established to 25% with the index of spontaneous proliferation remained on zero mark. Animals with embryocarcinoma after FDT with X-e6 with or without glycosamine show immunostimulating effect.

Study of LED Radiation Effects on Insect Phototaxis Response for the Development of Light-Based Pest Trap

Commercial agriculture is a resource intensive industry that employs significant amounts of agrochemicals to maintain a high yield output. Excessive application of insecticides has detrimental impacts on human health, environment and long-term sustainability. One particular area of interest is in exploring how insects are attracted to specific bands of the visible light spectrum. This paper details the study of several light conditions using Light Emitting Diodes (LEDs) to determine its phototaxis response on the common grasshopper, garden moth and lava beetle. The results conclude that all three insects exhibit positive phototaxis response on wavelengths around 491nm and below, which encompasses ultraviolet, blue and green. The radiant intensity experiment revealed a threshold response of 2.8mW/m2, or 25m in reciprocal distance.

Development of a Face Recognition System and Its Intelligent Lighting Compensation Method for Dark-Field Application

A face recognition system that uses 3-D lighting estimation and optimal lighting compensation for dark-field application is proposed. To develop the proposed system, which can realize people identification in a near scene dark-field environment, a light-emitting diode (LED) overhead light, eight LED wall lights, a visible light binocular camera, and a control circuit are used. First, 68 facial landmarks are detected, and their coordinates in both image and camera coordinate systems are computed. Second, a 3-D morphable model (3DMM) is developed after considering facial shadows, and a transformation matrix between the 3DMM and camera coordinate systems is estimated. Third, to assess lighting uniformity, 30 evaluation points are selected from the face. Sequencing computations of LED radiation intensity, ray reflection luminance, camera response, and face lighting uniformity are then carried out. Ray occlusion is processed using a simplified 3-D face model. Fourth, an optimal lighting compensation is realized: the overhead light is used for flood lighting, and the wall lights are employed as meticulous lighting. A genetic algorithm then is used to identify the optimal lighting of the wall lights. Finally, an Eigenface method is used for face recognition. The results show that our system and method can improve face recognition accuracy by >10% compared to traditional recognition methods.

Investigation of temperature dependence of radiation from semiconductor lasers and light emitting diodes

The investigation of temperature dependences of the radiation from red semiconductor laser diodes and light emitting diodes (LEDs) made on the basis of AlGaInP quadruple solid solution has been carried out. Despite the fact that the basic reasons for the change in the wavelength of laser and LEDs radiation when the temperature changes are considered to be known, however, the details of this effect are not well understood. The research shows experimentally how the radiation wavelength changes with temperature changes in the range from -20° C to 40°C for both a semiconductor laser and a LED. It was found that the rate of change in the radiation wavelength of the devices under study differs when the temperature changes. Two linear sections can be distinguished on the laser diode dependence of the wavelength on temperature X(T), while the LED has one section on the dependence X(T). The paper provides an explanation of the observed patterns based on the analysis of the possible influence of various factors. The study is relevant due to the fact that the devices under study are operated in the Arctic region, both at low and high temperatures, and there is insufficient information about the effect of temperature on the radiation characteristics of the studied devices.

Black Mesoporous Silicon as a Contrast Agent for LED-Based 3D Photoacoustic Tomography.

Mesoporous silicon (PSi) nanoparticles have been widely studied in different biomedical imaging modalities due to their several beneficial material properties. However, they have not been found to be suitable for photoacoustic imaging due to their poor photothermal conversion performance. In the present study, biodegradable black mesoporous silicon (BPSi) nanoparticles with strong light absorbance were developed as superior image contrast agents for photoacoustic tomography (PAT), which was realized with a light-emitting diode (LED) instead of the commonly used laser. LED-based PAT offers the advantages of low cost, compactness, good mobility, and easy operation as compared to the traditional laser-based PAT modality. Nevertheless, the poor imaging sensitivity of the LED-PAT systems has been the main barrier to prevent their wide biomedical application because the LED light has low optical energy. The present study demonstrated that the imaging sensitivity of the LED-PAT system was significantly enhanced with the PEGylated BPSi (PEG–BPSi) nanoparticles. The PEG–BPSi nanoparticles were clearly detectable with a low concentration of 0.05 mg/mL in vitro and with an LED radiation energy of 5.2 μJ. The required concentration of the PEG–BPSi nanoparticles was 10 times lesser than that of the reference gold nanoparticles to reach the corresponding level of the imaging contrast. The ex vivo studies demonstrated that the submillimeter BPSi nanoparticle-based absorbers were distinguishable in chicken breast tissues. The strong contrast provided by the BPSi particles indicated that these particles can be utilized as novel contrast agents in PAT, especially in LED-based systems with low light intensity.

Photocatalytic Degradation of 2,4-Dichlorophenoxyacetic Acid in Aqueous Solution Using Mn-doped ZnO/Graphene Nanocomposite Under LED Radiation

Chemical pesticides and herbicides are one of the most important pollutants in urban, agricultural and industrial wastewaters. Improper discharge of these compounds into water bodies’ cause harmful effects on both environment and human health. In this study, photocatalytic degradation of 2,4-Dichlorophenoxyacetic acid (usually called 2,4-D) was investigated using Mn-doped zinc oxide/graphene nanocomposite under light emitting diodes (LED) radiation. FTIR, AFM, DLS, Zeta potential, XRD, and SEM techniques were used to determine the characteristics of the nanocomposite. The effects of process-related parameters, such as the amount of nanocomposite, initial pH, 2,4-D concentrations, and contact time, on the photocatalytic degradation of the 2,4-D were studied. The results showed that the efficiency of photocatalytic degradation of 2,4-D decreased with an increase in the initial concentration of 2,4-D, while photocatalytic degradation efficiency increased by increasing the initial pH and the nano-catalyst content. The results showed that 66.2% of 2,4-D could be photocatalytically degraded using Mn-doped zinc oxide/graphene nanocomposite under LED radiation at optimal conditions (pH 5, initial Zn concentration of 10 mg L−1, nano-composite concentration of 2 g L−1, contact time of 120 min). Findings of this experimental study concluded that photocatalysis using Mn-doped zinc oxide/graphene nanocomposite under LED radiation could efficiently remove 2,4-D herbicide from aqueous media.

АНАЛИЗ ЛЕЧЕНИЯ ЭКСПЕРИМЕНТАЛЬНОГО АЛЬВЕОЛИТА ЧЕЛЮСТЕЙ У КРЫС С ПРИМЕНЕНИЕМ НИЗКОВОЛНОВОГО ЛАЗЕРНОГО ИЗЛУЧЕНИЯ И ЛЕКАРСТВЕННОГО ПРЕПАРАТА НА ОСНОВЕ «ГРАМИЦИДИНА С»

Background. The article deals with the problem of jaw alveolitis on the background of alveolar sockets infection on the example of experimental alveolitis in rats. The authors obtained and analyzed the results of treatment of alveolitis with the use of light emitting diode radiation radiation and a medical based on "Gramicidin C" and the classical method of treatment of alveolitis by microscopy of histological material Objectives ― study and prove that the infection of the well is a significant factor in the development of the alveolitis of the alveolar sockets on the example of experimental alveolitis in rats. To evaluate the effectiveness of treatment of alveolitis by the author's method using a light emitting diode radiation and a medical based on the antibiotic Gramicidin C, by microscopy of histological material represented by a bone fragment covered with a mucous membrane and including a tooth well with a developed alveolitis. Methods. Clinical and histological examination in dynamics of two groups of animals with developed experimental jaw alveolitis was carried out. The first group of animals was treated with alveolitis by the author's method ― using light emitting diode radiation and a medical based on the antibiotic "Gramicidin C". The control group of animals was treated according to the classical method using iodoform gauze. Results. The result of histological examination of the material of the bone fragment are covered with mucous membrane and which includes the alveolar sockets with alveolitis developed, the data obtained on high efficiency of use of the medicinal product on the basis of Gramicidin C in combination with light emitting diode radiation for the relief of alveolitis.

Infrared micro-thermography of high-power AlInGaN LEDs using high emissivity (black) in IR and transparent in the visible spectral region coating

ABSTRACTFor modern high-power LEDs, self-heating becomes a critical factor determining their functional characteristics and lifetime. For large-area LEDs with a complex structure, it is important to know not only the thermal resistance but also the detailed temperature distribution (temperature map) over the active area. We report a technique which can simplify and improve the Infrared (IR) micro-thermography of light-emitting diodes (LEDs) by the use of a special thin-film coating which combines strong absorption in the wavelength range of sensitivity of IR microscope (2.5–3 μm) and transparency in the visible region of the own LED radiation. As known, conventional IR temperature measurements, made on the LEDs, lead to significant difficulties and errors as a consequence of the optical transparency of substrate/heterostructure layers and a low emissivity of metallised contacts. The proposed method allows avoiding the time-consuming procedure of emissivity calibration for different materials forming LEDs while increasing the measurement accuracy.