How long does the biological effect of a red light-emitting diode last on adipose-derived mesenchymal stem cells?

This research investigated the duration of the influence of red light-emitting diodes (LED, 630 nm; output power: 2452.5 mW; laser beam: 163.5 cm2; irradiance: 15 mW/cm2; radiant exposure: 4 J/cm2) on different periods after irradiation (6, 12, 24, 48, and 72 h) on adipose-derived mesenchymal stem cells' (AdMSCs) metabolism and paracrine factors. AdMSCs were irradiated three times every 48 h. Twenty-four hours after the last irradiation, there was a higher MTT absorbance, followed by a decrease after 48 h. The cells' secretome showed increased levels of IL-6 and VEGF after 12 and 24 h, but this was reversed after 48 h. Additionally, LED irradiation resulted in higher levels of nitrite and did not affect oxidative stress markers. LED irradiation had significant effects on AdMSCs after 24 h compared to other groups and its control group.

Evaluation of bond strength in customizing fiber post using translucent resins photoactivated by different light-emitting diodes.

Aims: The objective of the study was to evaluate two translucent resin composite systems for customizing light-polymerized fiber posts with light-emitting diode (LED) curing units regarding adhesion using conventional cement at 24 h and 6 months. Settings and Design: This was an experimental in vitro study. Methods: Forty roots were prepared and divided into four groups (n = 10): ZV-Z350 resin and LED Valo; ZR-Z350 resin and LED Radii-Cal; OV-Opallis resin and LED Valo; and OR-Opallis resin and LED Radii-Cal. The fiber post was customized and cemented with conventional resin cement and was photoactivated by two different sources. Statistical Analysis Used: The data were subjected to two-way ANOVA and Tukey's post hoc tests (P = 0.05). The data regarding the pattern of adhesive failures were described in terms of the frequency of occurrence in each third of the postspace. Results: Both at 24 h and 6 months, bond strength among groups was similar, regardless of the analyzed postspace 3rd (P > 0.05). Adhesive failure Type 4 was the most frequent in all thirds. Conclusions: Customizing the fiber post with Z350 and Opallis has the same effect on bond strength and adhesive failure pattern, regardless of the LED curing units used for photopolymerization.

Field comparison of broad-spectrum white LED-baited traps with narrow-spectrum green LED-baited traps in the capture of Anopheles mosquitoes (Diptera: Culicidae).

Light-Emitting Diodes (LEDs) have been effective light sources in attracting Anopheles mosquitoes, but the broad-spectrum white light, even with a wide-ranging application in lighting, have not been evaluated yet. In this study, the white light was field evaluated against the green one in the light trapping of anopheline mosquitoes by using two non-suction Silva traps and two CDC-type suction light traps. Anopheline mosquitoes were captured for two 21-night periods of collecting (2022 and 2023). In the first period, two LEDs were used per Silva trap, but three were used in the second one to increase the luminance/illuminance at traps. A CDC-type suction light trap equipped with an incandescent lamp was used in 2022 and a CDC-type suction light trap equipped with a 6 V-white light (higher luminance/illuminance) in 2023. A total of eight species and 3,289 specimens were captured in both periods. The most frequent species were Anopheles triannulatus s.l., An. goeldii, An. evansae and An. argyritarsis. In 2022, white LEDs were less attractive to anopheline mosquitoes than the other light sources, but without statistical difference among treatments (F = 2.703; P = 0.0752; df = 2). In 2023, even with an increased luminance/illuminance at traps, no statistical difference was found between the two LED-baited Silva traps (F = 6.690; P = 0.0024; df = 2), but rather between the 6 V-white-baited CDC-type suction light trap and green-baited Silva traps. Due to some drawbacks and the lower abundance of individuals caught by using white LEDs, the narrow-banded green LEDs is preferable to white ones for attracting anophelines.

Repercussion of inflammatory bowel disease on lung homeostasis: The role of photobiomodulation.

Inflammatory bowel diseases (IBD) are chronic and multifactorial diseases characterized by dysfunction of the intestinal mucosa and impaired immune response. Data show an important relationship between intestine and respiratory tract. The treatments of IBD are limited. Photobiomodulation (PBM) is an effective anti-inflammatory therapy. Our objective was to evaluate the repercussion of IBD as well as its treatment with PBM on pulmonary homeostasis. Male Wistar rats were submitted to IBD induction by acetic acid and treated or not with PBM. Rats were irradiated with red LED on both right and left sides of the ventral surface and beside the external anal region during 3 consecutive days (wavelenght 660 nm, power 100 mw, total energy 15 J and time of irradiation 150 s per point). Our results showed that IBD altered pulmonary homeostasis, since we observed an increase in the histopathological score, in myeloperoxidase activity (MPO), in mast cell degranulation, and in the release and gene expression of cytokines. We also showed that PBM treatment reduced biomarkers of IBD and reverted all augmented parameters in the lung, restoring its homeostasis. Thus, we confirm experimentally the important gut-lung axis and the role of PBM as a promising therapy.

Red light-emitting diode therapy minimizes the functional deleterious effects of the antiretroviral ritonavir on osteoblasts in vitro.

PURPOSE: Long-term human immunodeficiency virus (HIV)-infected patients are considered at higher risk for osteoporosis. Among the various causes that lead these patients to lower bone health, there is the use of antiretroviral drugs (ARVs), especially protease inhibitors (PI), such as ritonavir (RTV). In this context, emerge the potential benefits of LED therapy, whose effects on bone cells are currently being extensively studied, showing a modulation in cell differentiation. However, it remains unclear if photobiostimulation might interfere with RTV effects on osteoblast differentiation. METHODS: In the present study, we investigated the effects of red LED (625 nm) irradiation (15 mW/cm2, 0.2 J/cm2, and 8 mW/cm2, 0.12 J/cm2) on osteoblast cell line MC3T3-E1 treated with RTV (2.5, 5, and 10 µg/mL). RESULTS: Our results indicated that red LED irradiation was able to reverse, or at least minimize, the deleterious effects of RTV on the osteoblasts. Neither the ARV treatments 5 and 10 µg/mL (104.4% and 95.01%) nor the LED protocols (100.3% and 105.7%) statistically altered cell viability, assessed by the MTT assay. Also, the alkaline phosphatase activity and mineralization showed a decrease in osteoblast activity followed by ARV exposure (39.3-73%), which was attenuated by LED in more than 70% with statistical significance (p < 0.05). CONCLUSION: In conclusion, photobiostimulation with red LED at 625 nm was associated with improved beneficial biological effects as a potential inducer of osteogenic activity on RTV-affected cells. This is the first study that investigated the benefits of red LED irradiation over ARV-treated in vitro osteoblasts.

Photobiomodulation therapy (red/NIR LEDs) reduced the length of stay in intensive care unit and improved muscle function: A randomized, triple-blind, and sham-controlled trial.

CONTEXT: Photobiomodulation therapy (PBMT) has been widely used to improve strength, fatigue resistance and increase muscle mass in healthy individuals. These effects could help critically ill patients admitted to intensive care units (ICUs) who show reduced mobility and muscle strength. ICU-acquired weakness lessens overall health and increases the patient's length of stay in the ICU. OBJECTIVE: This study evaluated the effects of PBMT using low intensity light-emitting diodes (LEDs) on the mobility and muscle strength (functional capacity) and length of stay of patients admitted to hospital ICU. METHODS: This randomized, triple-blind, sham-controlled trial was conducted in a hospital ICU. Sixty patients were randomly assigned to two equal groups: (a) PBMT and (b) Sham. PBMT was applied daily to patients until their discharge from the ICU, using a flexible neoprene array of 264 LEDs (120 at 635 nm, 1.2 mW each; 144 at 880 nm, 15 mW each) for 90s (207.36 Joules) at each site. Ten sites were located bilaterally on the thighs, legs, arms, and forearms ventrally and dorsally, 15 min totaling 2,073.6 Joules per session. Outcomes were length of stay (in h) until discharge from the ICU, muscle strength by the Medical Research Council (MRC) score and handgrip dynamometry (HGD), patient mobility by Intensive Care Unit Mobility Scale (IMS) and the Simplified Acute Physiology Score 3 (SAPS 3) for predicting mortality of patients admitted to the ICU. RESULTS: PBMT reduced the average length of stay in the ICU by ~30% (p = 0.028); increased mobility (IMS: 255% vs. 110% p = 0.007), increased muscle strength (MRC: 12% vs. -9% p = 0.001) and HGD (34% vs. -13% p < 0.001), and the SAPS3 score was similar (p > 0.05). CONCLUSION: The results suggest that daily PBMT can reduce the length of stay of ICU patients and increase muscle strength and mobility.

Delphinidins from Maqui Berry (Aristotelia chilensis) ameliorate the subcellular organelle damage induced by blue light exposure in murine photoreceptor-derived cells.

BACKGROUND: Blue light exposure is known to induce reactive oxygen species (ROS) production and increased endoplasmic reticulum stress, leading to apoptosis of photoreceptors. Maqui berry (Aristotelia chilensis) is a fruit enriched in anthocyanins, known for beneficial biological activities such as antioxidation. In this study, we investigated the effects of Maqui berry extract (MBE) and its constituents on the subcellular damage induced by blue light irradiation in mouse retina-derived 661W cells. METHODS: We evaluated the effects of MBE and its main delphinidins, delphinidin 3-O-sambubioside-5-O-glucoside (D3S5G) and delphinidin 3,5-O-diglucoside (D3G5G), on blue light-induced damage on retinal cell line 661W cells. We investigated cell death, the production of ROS, and changes in organelle morphology using fluorescence microscopy. The signaling pathway linked to stress response was evaluated by immunoblotting in the whole cell lysates or nuclear fractions. We also examined the effects of MBE and delphinidins against rotenone-induced mitochondrial dysfunction. RESULTS: Blue light-induced cell death, increased intracellular ROS generation and mitochondrial fragmentation, decreased ATP-production coupled respiration, caused lysosomal membrane permeabilization, and increased ATF4 protein level. Treatment with MBE and its main constituents, delphinidin 3-O-sambubioside-5-O-glucoside and delphinidin 3,5-O-diglucoside, prevented these defects. Furthermore, MBE and delphinidins also protected 661W cells from rotenone-induced cell death. CONCLUSIONS: Maqui berry may be a useful protective agent for photoreceptors against the oxidative damage induced by exposure to blue light.

Photobiomodulation Using Light-Emitting Diode (LED) for Treatment of Retinal Diseases.

Photobiomodulation (PBM) is a type of phototherapy that employs light-emitting diodes (LEDs) or low-power lasers to selectively administer specific wavelengths of visible light, ranging from 500 to 1000 nm, including near-infrared (NIR) wavelengths. LEDs are advantageous compared to lasers due to their ability to treat large areas at a lower cost, lack of tissue damage potential in humans, and reduced risk of eye-related accidents. The ophthalmology community has recently taken interest in PBM as a promising novel approach for managing various retinal conditions such as age-related macular degeneration, retinopathy of prematurity, retinitis pigmentosa, diabetic retinopathy, Leber's hereditary optic neuropathy, amblyopia, methanol-induced retinal damage, and potentially others. This review critically assesses the existing body of research on PBM applications in the retina, focusing on elucidating the underlying mechanisms of action and evaluating the clinical outcomes associated with this therapeutic modality.

Optimizing UVC-LED application to improve the shelf life of vacuum-packed refrigerated stored Nile tilapia (Oreochromis niloticus) fillets.

Although ultraviolet-C light-emitting diode (UVC-LED) has proven antimicrobial effectiveness doses needed to reach it cause adverse effects on the physicochemical quality of fish, and thus, optimization studies are crucial to boost its industrial application. This study aimed to identify optimal UVC-LED conditions for maximum shelf life extension with the least possible quality changes of refrigerated stored tilapia fillets from a central composite rotatable design (CCRD). UVC-LED powers (1, 1.38, and 1.58 mW/cm2 ) and times (500, 1800, and 2700 s) were set on the CCRD, which generated 11 treatments, including three replicate experiments. Treatments were analyzed for total aerobic psychrotrophic count, lipid oxidation, instrumental color, and texture parameters on days 0, 2, 4, 7, 11, and 14. The UVC-LED affected shelf life and physicochemical parameters in a nonlinear fashion. UVC-LED-treated fish had increased shelf life by 2.80-4.76 days and increase or decrease in lipid oxidation (0.025-0.276 mg of malondialdehyde [MDA]/kg), total color change (∆E = 3.47-9.06), and hardness (1.31-8.51 N) over the refrigerated storage depending on specific UVC-LED conditions applied. The optimal UVC-LED condition was 0.97 mW/cm2 with 2503.6 s (2428.50 mJ/cm2 ), which increased the fillet's shelf life by 2.5-fold (2 days) while maintaining quality closer to the original throughout refrigerated storage, resulting in ∆E < 5, an increase of only 0.05 mg of MDA/kg, and preservation of the decrease in hardness by 3.38 N compared to its control counterparts. Therefore, it represents an eco-friendly technology that can easily scaled industrially to enhance the sustainable fish production chain. PRACTICAL APPLICATION: The high fish perishability is a global concern due to food safety risks and waste generation impacting the environment adversely, especially nowadays, where fish production and consumption have increased, and there are more evident efforts to sustainable production. UVC-LED is an eco-friendly technology with proven antimicrobial effectiveness but doses needed to reach this effect enhance oxidative degradation. Despite that, optimization studies concerning the maximum shelf life extension while retaining the physicochemical quality of refrigerated stored fish are a gap in the literature and a barrier to its industrial application. Our findings are helpful in sustainably enhancing the fish production chain.

Can Extraintestinal Pathogenic Escherichia coli with Heat Resistance Profile Overcome Nonthermal Technologies?

Ultraviolet-C light-emitting diode (UVC-LED) and ultrasound (US) are two nonthermal technologies with the potential to destroy pathogens. However, little is known about their effectiveness in strains with a history of heat resistance. Thus, this study aimed to evaluate the phenotype and genotype of heat-resistant extraintestinal pathogenic Escherichia coli (ExPEC) with heat resistance genes after the application of US, UVC-LED, and UVC-LED+US. For this, two central composite rotatable designs were used to optimize the UVC-LED and US conditions in four ExPEC isolated from beef. From the genome of these isolates obtained in a previous study, possible genes for UVC resistance were analyzed. Results showed that US was ineffective in reducing >0.30 log colony-forming unit/mL, and that when used after UVC-LED, it showed a nonsynergic or antagonistic effect. Also, UVC-LED had the greatest effect at the maximum dose (4950 mJ/cm2 from 1.65 mW/cm2 for 50 min). However, the strains showed some recovery after that, which could be implicated in the expression of genes included in SOS system genes, some others present in the transmissible Locus of Stress Tolerance (trxBC and degP), and others (terC). Thus, ExPEC can overcome the conditions used in this study for US, UVC-LED, and UVC-LED+US, probably due to the history of resistance to other cellular damage. The result of this study will contribute to future studies that aim to find better treatment conditions for each food product.

Field evaluation of a new suction light trap for the capture of phlebotomine sand flies (Diptera: Psychodidae: Phlebotominae), vectors of leishmaniasis.

Phlebotomine sand flies are crepuscular and nocturnal small dipteran insects in the family Psychodidae. Several disease agents, including Leishmania parasites, are transmitted to humans and other vertebrate hosts by the bite of an infected female sand fly. As part of leishmaniasis surveillance programs, light traps have been routinely used in sand fly collections. In this context, new trapping devices are always being required to improve vector monitoring. Here, the efficiency of a new suction light trap, named Silva suction trap or SS trap, was field evaluated in collecting sand flies. Two SS traps, one with green (520 nm, 15,000 mcd) and the other with white (wide spectrum, 18,000 mcd) LEDs, and one CDC-type trap were deployed in a rural forested environment. A total of 4686 phlebotomine sand flies were captured. The most frequent species were females of the Ps. Chagasi series (77.8%) followed by males of Ps. wellcomei (11.6%), Nyssomyia whitmani (3.3%), and Bichromomyia flaviscutellata (2.4%). The CDC-type light trap collected 101.9 ± 20.89 sand flies and 14 species, followed by the white-baited SS trap (87.78 ± 16.36, 14), and the green-baited SS trap (70.61 ± 14.75, 15), but there were no statistically significant differences among traps. A discussion on the considerable advantages of the use of SS traps over CDC traps is included. In this study, the Silva suction trap proved to be efficient and can be an alternative to CDC traps for monitoring adult phlebotomine sand fly populations.

LED-irradiated photo-Fenton process on pollutant removal: outcomes, trends, and limitations.

This manuscript critically reviews the state of the art on the application of photo-Fenton processes irradiated by light-emitting diode arrays (LED) with a focus on the removal of contaminants of emerging concern (CEC) from aqueous matrices. LEDs are clean, low-cost radiation sources with longer lifespan compared to mercury lamps. This study covers the influence of LED sources, wavelengths, and dose upon CEC removal, and the potential for disinfection, abatement of antibiotic-resistant bacteria (ARB), and genes (ARG). The bibliographic search was performed in Scopus database using keyword combinations and resulted in a portfolio containing 52 relevant articles published between 2010-2023. According to reviewed papers, LED photoreactor design has evolved in the past decade aiming to improve CEC degradation in aqueous matrices while reducing construction and operation costs, and energy consumption. Among several reactors (annular, fluidized bed, parallel plate, wireless, pathway systems, and microreactor) surveyed for their performance and scalability, LED chips and strips are particularly suitable for application due to their wide emission angle (≈120°) and small size (mm2), which allow for, respectively, efficient illumination coverage and flexible arrangement and design. LED microreactors are very efficient in the degradation of contaminants and scalable with reduced area requirements. Although most studies were performed in synthetic solutions and at laboratory scale, the externally LED irradiated cylindrical reactor was successful for application in full-scale municipal water treatment plants. Future studies should focus on evaluating CEC removal in wastewater using scalable devices for continuous operation of solar photo-Fenton at night.

Influence of photobiomodulation therapy on the physical performance of women during the follicular phase of the menstrual cycle: A double-blind Sham-controlled randomized clinical trial.

To evaluate the effects of photobiomodulation on the physical performance of healthy women, considering the menstrual cycle. 27 physically active healthy women (age 25.68 ± 3.99 years; mass 63.76 ± 12.77 kg; height 1.65 ± 0.59 cm) during the initial follicular phase (FF1 and FF2) of the menstrual cycle underwent performance evaluations, through a supramaximal test, subjective perception of exertion, blood lactate, and evaluations in the isokinetic dynamometer. Photobiomodulation (PBM) (200J) and Sham (0J) therapy were applied 10 min before the performance evaluations on the quadriceps femoris, hamstrings, and triceps surae muscles. A significance level of 5% was adopted and the effect size was calculated by Cohen's d. It was not possible to observe a significant difference (p > 0.05) in any of the performance variables evaluated in the comparison between groups, only small effects for total distance, final subjective perception of exertion, lactate peak and lactate delta in the PBM group. PBM did not improve muscle performance, resistance to fatigue, perceived exertion, and blood lactate concentrations during a predominantly anaerobic test in healthy women during the FF of the menstrual cycle.

Effects of Violet and IR LED Light on mast cell degranulation: in vivo study in a murine model.

The aim of this study was to evaluate the influence of IR (λ850 ± 10 nm) and violet (λ405 ± 10 nm) LED phototherapy on total mast cells counts and its ability to influence mast cell degranulation. For this, 27 Wistar rats were used and were randomly distributed into three groups: control, IR LED, and violet LED. When indicated, irradiation done and they were sacrificed, had their tongue removed immediately, 20-min, 45-min, and 2-h after irradiation. Samples were processed to wax, cut, and stained with Toluidine Blue. Intact and degranulated mast cells were counted under light microscopy, and statistical analysis was carried out. In the superficial connective tissue and muscular tissues, violet LED light caused a significant increase in both total number and degranulated mast cells when compared to the control group immediately after irradiation. The degranulation indexes were higher in the groups irradiated with Violet light, both in superficial connective tissue and muscular tissues in relation to the timing. Irradiation with IR LED caused immediate increase in the total number and degranulated of mast cells when compared to the control group only in the superficial connective tissue. In all times observed, the highest total amount of mast cells was seen immediately after irradiation, except in the muscular tissue, which presented the highest amount after 20-min. It was concluded that IR and violet LED light were able to increase the number of mast cells and inducing degranulation in oral mucosa. However, considering that violet LED light can be harmful in periodontal disease, it seems that the use of IR LED light could be the best option in Dentistry.

Effects of photobiomodulation therapy (PBMT) on the management of pain intensity and disability in plantar fasciitis: systematic review and meta-analysis.

To review the effects of photobiomodulation therapy (PBMT) on pain intensity and disability in people with plantar fasciitis (PF) when compared with control conditions, other interventions, and adjunct therapies. Systematic searches were conducted in five database randomized controlled trials (RCT). We only included randomized controlled trials (RCTs) in adults with PF that compared PBMT to placebo, as well as RCTs that compared PBMT to other interventions; and as an adjunct to other therapies. The methodological quality and certainty were assessed through PEDro Scale and GRADE approach, respectively. The data of comparison were pooled and a meta-analysis was conducted when possible. Nineteen RCTs involving 1089 participants were included in this review. PBMT alone (MD = - 22.02 [- 35.21 to - 8.83]) or with exercise (MD = - 21.84 [- 26.14 to - 17.54]) improved pain intensity in short-term treatment. PBMT was superior to (extracorporeal shock wave therapy) EWST for relief of pain (MD = - 20.94 [- 32.74 to - 9.13]). In the follow-up, PBMT plus exercise had a superior to exercise therapy alone (MD = - 18.42 [- 26.48 to - 10.36]). PBMT may be superior to (ultrasound therapeutic) UST in medium- and long-term follow-ups for disability, but can be not clinically relevant. There is uncertainty that PBMT is capable of promoting improvement in disability. PBMT when used with adjuvant therapy does not enhance outcomes of interest. PBMT improves pain intensity with or without exercise. PBMT has been shown to be superior to ESWT for pain relief, but not superior to other interventions for pain intensity and disability. The evidence does not support PBMT as an adjunct to other electrotherapeutic modalities.

Effectiveness of Light-Emitting Diode Epilation on Different Skin Types: A Pilot Study.

Objective: This study analyzed the histological and immunohistochemical changes in hair follicles submitted to epilation with light-emitting diode (LED). Background: The use of specific wavelengths of LED leads to the absorption of photons by chromophore tissues, enabling different photophysical and photochemical events, bringing therapeutic benefits such as removing body hair. Methods: The sample included five participants, with phototypes II-V, divided into two groups. The volunteers received a session of epilation with the Holonyak® device on the pubic region and right groin, whereas the contralateral side was kept as a control. An energy of 10 J and a cooling temperature of -5°C were used, after which the pain provoked by the equipment was questioned using the analogue pain scale. After 45 days, the punching procedure was performed in the region where skin samples were taken for histological and immunohistochemical analysis. Results: For all phototypes, in the treated area, the follicles and sebaceous glands were in a stage of involution, showing perifollicular inflammatory infiltrate with changes suggestive of apoptosis. The apoptosis process was confirmed by the increase in markers cytokeratin-18 and cleaved caspase 3, in addition to the reduced expression of Blc-2, and the lower cell proliferation (Ki67), reinforcing the action of LED based on the definite involution and resorption of the follicle, through macrophages (CD68) triggered by the inflammatory process. Conclusions: The preliminary results of this study found relevant histological changes and immunohistochemical markers in the epilation process, which may indicate the efficacy of LED in permanent hair removal.

Light-emitting diode (LED) photobiomodulation regulates thermogenesis and lipogenesis markers in adipose tissue and improves anthropometric and metabolic parameters in obese mice.

To evaluate the effects of Light-Emitting Diode (LED) irradiation on the expression of thermogenesis and lipogenesis-associated markers in adipose tissue and metabolic parameters of obese mice. Twenty-four male mice were divided into four groups: i) ST fed standard diet; ii) HCD fed hyperglycemic diet; iii) LED + I fed hyperglycemic diet and irradiated with LED in the interscapular region; iv) LED + A fed hyperglycemic diet and irradiated with LED in the abdominal region. The first phase of the study comprehended the induction of obesity for 12 weeks. Next, the animals were submitted to six irradiation sessions (days 1, 3, 7, 10, 14, and 21) using a 660-nm LED (5.77 J/cm2 at 48,1 mW/cm2). Anthropometric, biochemical, and histological parameters and the expression of thermogenesis and lipogenesis-associated markers were assessed in adipose tissue. There was diminished weight gain between the HCD and LED + A groups (ST: 0.37 ± 0.65; HCD: 3.10 ± 0.89; LED + I: -1.26 ± 0.83; LED + A: -2.07 ± 1.27 g; p < 0.018). There was a 33.3% and 23.8% reduction in epidydimal adipose tissue weight and a 25% and 10.7% in the visceral adiposity for the LED + I and LED + A groups, respectively, when compared with HCD. There was a decreased accumulation of fat droplets in adipose tissue in LED + A and LED + I groups. Additionally, LED irradiation was associated with increased mRNA expression of uncoupling protein 1 (UCP1) in the brown adipose tissue (ST: 2.27 ± 0.19; HCD: 1.54 ± 0.12; LED + I: 2.44 ± 0.22; p = 0.014) and decreased fatty acid synthetase (FAS) expression in epidydimal adipose tissue (ST: 0.79 ± 0.13; HCD: 1.59 ± 0.13; LED + A: 0.85 ± 0.04; p = 0.0008). LED treatment improved anthropometric parameters, possibly associated with the histological alterations, thermogenesis and lipogenesis markers in white adipose tissue, and expression modulation in brown adipose tissue.

Microleakage of Class II Bulk-Fill Resin Composite Restorations Cured with Light-Emitting Diode versus Quartz Tungsten-Halogen Light: An In Vitro Study in Human Teeth.

Background: Resin composites undergo a certain degree of shrinkage when light-cured with different light sources available on the market, resulting in microleakage of dental restorations. The aim of the present study was to assess microleakage of class II restorations with bulk-fill resin composites cured with LED (light-emitting diode) and QTH (quartz tungsten-halogen light) units, both in cervical and occlusal areas of cavity preparations. Materials and Methods: In the present in vitro experimental study, a total of 30 human molar teeth were used, in which 60 class II cavities were prepared (mesial and distal) and restored with Filtek bulk fill resin composite. Restorations were equally distributed in 3 groups according to type of curing light: A, QTH (Litex 680A Dentamerica®); B, LED (Bluephase N® 3rd generation); and C, LED (Valo® 3rd generation). Each group was further subdivided into subgroups 1 and 2 according to IV-A or IV-B resin composite color. Restored teeth were subjected to 20,000 thermal cycles between 5° and 55 °C, then immersed in 1M silver nitrate solution for 24 h. Subsequently, the teeth were sectioned mesiodistally to obtain samples for observation under stereomicroscope in order to determine microleakage degree. Kruskal-Wallis H and Mann-Whitney U statistical tests were applied with a significance level of 5% (p < 0.05). Results: No statistically significant differences were found in the degree of microleakage of bulk-fill resin composites light-cured with LED and QTH units for both occlusal (p > 0.05) and cervical areas (p > 0.05). Additionally, no significant differences were found when comparing microleakage between occlusal and cervical areas (p > 0.05), regardless of lamp type. In addition, significant differences in microleakage degree were found between bulk-fill resins with IV-A and IV-B shades when they were light-cured with QTH at cervical level (p = 0.023). However, there were no significant differences when comparing these bulk-fill resin composite shades at occlusal level with LED (p > 0.05) and QTH (p > 0.05) units. Conclusions: Class II restorations with bulk-fill resin composite in IV-A and IV-B shades light-cured with third generation LED lamp and QTH showed no significant differences in microleakage when compared in both occlusal and cervical areas. On the other hand, significantly more microleakage was found at the cervical level when a darker shade of resin composite was used and light-cured with the QTH unit.

The biological effects of different LED wavelengths in the health field. A review / Os efeitos biológicos de diferentes comprimentos de onda de LED na área da saúde. Uma revisão

Introduction: the use of light emitting diodes (LED) in domestic and public vias have increased in the last 20 years. In addition, the LED light has been used as a light source for medical applications. Objective: since humans are increasingly exposed to LEDs, there is an urgency to investigate the possible biological effects on tissues caused by this exposure. So, researchers have been focused their investigations in the application of this light in the health field. Material and method: in this review, a search in important databases was performed on the biological effects caused after application of different LED light protocols in in vitro and in vivo studies. Result: although most published papers have shown positive results, some of them reported negative biological effects of light LEDs technology on humans' cells/tissues. Conclusion: therefore, the comprehension of the biological effects caused by light LEDs will provide a better assessment of the risks involved using this technology.

Introdução: o uso de diodos emissores de luz ("LED") em vias domésticas e públicas tem aumentado nos últimos 20 anos. Além disso, a luz LED tem sido usada para aplicações médicas. Objetivo: pelo fato de seres humanos estarem cada vez mais expostos aos LEDs, há urgência em investigar os possíveis efeitos biológicos nos tecidos causados por esta exposição. Assim, pesquisadores têm focado suas investigações no uso desta luz na área da saúde. Material e método: nesta revisão foi realizada uma pesquisa em bancos de dados conceituados sobre os efeitos biológicos causados após aplicação de diferentes protocolos de luz LED em estudos in vitro e in vivo. Resultado: embora a maioria dos artigos publicados tenham mostrado resultados positivos, alguns deles relataram efeitos biológicos negativos da tecnologia de LEDs nas células/tecidos humanos. Conclusão: portanto, a compreensão dos efeitos biológicos causados pela luz LED proporcionará uma melhor avaliação dos riscos envolvidos no uso desta tecnologia.

Theoretical and Computational Analysis of a Wurtzite-AlGaN DUV-LED to Mitigate Quantum-Confined Stark Effect with a Zincblende Comparison Considering Mg- and Be-Doping.

In this work, an AlGaN-based Deep-Ultraviolet Light-Emitting Diode structure has been designed and simulated for the zincblende and wurtzite approaches, where the polarization effect is included. DFT analysis was performed to determine the band gap direct-to-indirect cross-point limit, AlN carrier mobility, and activation energies for p-type dopants. The multiple quantum wells analysis describes the emission in the deep-ultraviolet range without exceeding the direct-to-indirect bandgap cross-point limit of around 77% of Al content. Moreover, the quantum-confined Stark effect on wavefunctions overlapping has been studied, where Al-graded quantum wells reduce it. Both zincblende and wurtzite have improved electrical and optical characteristics by including a thin AlGaN with low Al content. Mg and Be acceptor activation energies have been calculated at 260 meV and 380 meV for Be and Mg acceptor energy, respectively. The device series resistance has been decreased by using Be instead of Mg as the p-type dopant from 3 kΩ to 0.7 kΩ.