Laser fluenceformula

Corresponding author: You Chan Kim, Department of Dermatology, Ajou University School of Medicine, 164 World cup-ro, Yeongtong-gu, Suwon 16499, Korea. Tel: 82-31-219-5917, Fax: 82-31-216-9189, maychan@ajou.ac.kr

There is an additional factor, which is that our cones are not evenly spaced across the colour spectrum. We frequently represent the range of colours that we see as colour wheels, like the colour wheels above showing the mixing range of different colour combinations. However, our visual spectrum is better represented as this wonky horseshoe shape.

ANOVA was used to compare wound size reduction between treatment groups and the statistical analyses were performed using R software, version 3.5.2 (R Foundation for Statistical Computing, Vienna, Austria). p-values <0.05 were considered statistically significant. Summary data are expressed as the mean±standard deviation.

Fluenceunits

A few studies have directly compared the effects of different fluences of LLLT. Da Silva et al.6 investigated the effects of a 670 nm-wavelength laser on rats, by irradiating skin lesions with 0, 2, or 4 J/cm2 for 10 consecutive days. At 4 J/cm2, the re-epithelialization process was significantly faster than that in the other groups. A study using a 632.8 nm-wavelength laser reported that 3∼6 J/cm2 photostimulation facilitates the tissue repair process in diabetic wound healing by accelerating the rates of contraction and collagen production7. With irradiation at 830 nm, a preliminary investigation demonstrated that 5 J/cm2 LLLT improved wound healing, as measured by increased wound tensile strength8. A study in mice comparing the influences of 632.8, 785, and 830 nm lasers on burn wound healing found that treatment with 830 nm light at a fluence of 3 J/cm2 had profound effects on healing compared to untreated controls and mice treated with lasers of other wavelengths9. However, no studies have compared the effects of different fluences and irradiation durations on wound size reduction.

†Data are p-values, which are obtained by using t-test and corrected using the Bonferroni adjustment, which are significant when <0.05.

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In this study, we describe the effects of LLLT on wound size reduction in a standardized model of full-thickness excisional wound healing in mice, using an 830-nm diode laser with various fluence levels and durations of irradiation.

In conclusion, we have shown that repeated exposure to low levels of light significantly stimulates wound healing in mice and demonstrated more efficient wound closure with certain fluences of 830-nm irradiation. Conversely, the duration of irradiation did not significantly affect wound healing. Further studies regarding human wound healing will be required to examine the applicability of these results to clinical LLLT.

Right about now you might be getting confused. First I said that cyan, magenta and yellow were primary colours. Now I'm saying that blue, green and red are the "primary" colours, the building blocks that we see all other colours from. What gives?You see, there's a difference between how we perceive coloured light (different wavelengths of light) and coloured objects. Coloured light is a specific wavelength of light (or combination of wavelengths) shining at us. Coloured objects (like watercolour on a paper), are objects that absorb some wavelengths and reflect others. A yellow object, for example, will absorb blue light, reflecting a range of light wavelengths that trigger our green and red cones.It is impossible to mix a bright yellow from any colours except other yellows (except perhaps extremely yellowish greens and oranges) in paint, because as soon as you choose a slightly different colour, you will start reflecting some blue, or stop reflecting as much green or red, resulting in a mixed colour that we perceive as something other than yellow.The "primary" colours of cyan, magenta and yellow, in the context of painting, are the colours which we see least well. There's a huge range of different wavelengths and combinations that we perceive as green, blue or red, but fewer that we perceive as cyan, magenta and yellow.

Wound closure involves the migration of the boundaries of an injury towards its center and can be assessed through related parameters, such as the percentage of wound contraction10. In this study, we investigated the effect of LED irradiation fluence on wound closure and the effect of the duration of LED irradiation on wound closure. Regarding the results of day 5, the most potent fluence was 40 J/cm2. Demidova-Rice et al.11 evaluated the effects of laser therapy on excisional wounds and found that the dose effects are not linear for various fluences of 635-nm light, with a maximum positive effect at 2 J/cm2. They reported that intensities of 1 and 10 J/cm2 improved healing to a lesser extent, while 50 J/cm2 had a negative effect on wound healing. Using 670-nm laser therapy, treatment at 4 J/cm2 displayed superior wound healing than treatment at 8 J/cm2.12 Inadequate doses can result in weak and insignificant effects; while excessive doses can cause negative or minimal effects13. With even higher doses, a biosuppressive or inhibitory effect may be observed14. In contrast to these studies, we used 830-nm light and observed an optimal fluence of 40 J/cm2. As light at this wavelength can penetrate the skin more deeply, we hypothesize that a higher fluence of irradiation might be required for wound healing at 830 nm. Further study is needed to investigate whether over 40 J/cm2 of fluence of irradiation has harmful effect on wound healing.

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However, after day 5, we observed no statistically significant differences between the groups irradiated with different fluences. The wounds of all groups were almost closed at day 15. We also investigated the effects of treatment duration, and observed no statistically significant differences between the groups. Wound closure begins with an inflammatory phase and re-epithelialization, followed by the remodeling phase, which generally begins 5 to 7 days after injury. In a previous study, while healing curves generated for control mice demonstrated an initial decrease in wound size during days 1 to 4 after injury, the wounds of LLLT-treated mice started to contract immediately after illumination11. Therefore, 5 days of irradiation could be adequate to reduce the wound area.

†Data are p-values, which are obtained by using t-test and corrected using the Bonferroni adjustment, which are significant when <0.05.

On days 1, 5, 10, and 15, images of the wounds were acquired, and the wound areas were measured as the primary outcome using Image-Pro Plus 6.0 software (Media Cybernetics, Silver Spring, MD, USA). The wound size immediately after wound creation was designated the original wound area. The percentage of wound closure at each time point was calculated using the following formula and defined as the secondary outcome.

What isfluencein radiation

When two or more receptors both react to a light source, we see an in-between colour depending on how much each receptor reacted - for example, if we see both red and green light equally, we perceive it as yellow. If both blue and red receptors, far apart on the colour wheel, both react without triggering the green cones, we see an "imaginary" colour with no wavelength, magenta.Cyan, Magenta and Yellow are the three colours of light we see least well - narrow wavelength ranges only triggered at the outside edges where two receptors intersect.

Eight-week-old female albino hairless mice (Skh:hr-1) weighing 25∼30 g were maintained in individual ventilated cage systems. The animals were group-housed, ten mice per cage. Constant temperature, humidity, and a 12-hour light/dark cycle were maintained, and the mice were fed a standard diet. All experimental protocols were approved by the Committee for Animal Care and Use of Ajou University (approval no. 2017-0016).

If you want to mix a wide range of colours using few tubes of paints, some colour selections do provide a larger mixing gamut than others. Specifically, a primary triad consisting of cyan, magenta and yellow will give you the widest possible range of bright colours. What is special about these three colours?To answer this question, we need to understand how eyes work.

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Fluence laserhair removal

Full-thickness wounds were created on the dorsal skin using an 8-mm diameter punch, and the wounds were irradiated at 1, 4, or 40 J/cm2 for 5 consecutive days starting on day 1. To determine the optimal irradiation duration, wounds were irradiated at the most potent fluence of previous study for 5, 10, or 15 days. Photographic documentation, skin biopsies, and wound measurements were performed to compare the effects of different treatment parameters.

Our first goal was to identify the optimal fluence of LED irradiation to reduce the time required for wound closure. There were some variations in the sizes of the initial wounds, due to the difficulty in creating wounds in the flexible skin of the mice. Therefore, the relative wound area was analyzed along with the absolute values. Compared to the baseline values for each group, the wound areas in all groups steadily decreased over time (Fig. 1, 2). The wounds of all groups almost closed on day 15. Therefore, to assess when the effects of irradiation on wound healing appear, the analysis of wound closure at day 3, 5, 10 and 15 was done. When comparing the relative wound area in group A (control) with irradiated groups (group B, C, and D) respectively, more efficient wound closure was observed in group D (40 J/cm2) on day 5 (Table 1). At the same time, there was no significant difference in wound healing between groups A and B (1 J/cm2), C (4 J/cm2) respectively. Additionally, post hoc analysis was done and compared groups to each other. The most efficient fluence on day 5 was 40 J/cm2 (group D), which demonstrated significantly improved wound healing compared to all the groups. After day 5, no significant difference was observed among groups.

The other goal of our study was to identify the best duration of LED irradiation for wound healing. The effects of 5, 10, and 15 days of radiation (groups IR5, IR10, and IR15, respectively) were compared. Compared to their baseline values, wound areas steadily decreased in all groups (p< 0.001; Fig. 3, 4, and Supplementary Fig. 1). The wound healing was significant at day 5. The wounds of all groups almost closed on day 15. There was no significant difference in wound area reduction between the IR5 and IR10 groups nor between the IR5 and IR15 groups (Table 2). Post hoc analysis revealed no significant difference among the groups.

There is a huge range of colours that we can see, but simply cannot include in an object that doesn't emit light, like a painting. Think of bright neon lights.

Low-level lasers can affect lymphocytes, increasing their proliferation and activation; macrophages, increasing their phagocytosis; and fibroblasts, increasing their growth factor secretion and enhancing the uptake of both fibrin and collagen2. In addition, LLLT increases the motility of epithelial cells and the amount of granulation tissue produced during healing, and may reduce the synthesis of inflammatory mediators3,4, resulting in reductions in skin wound area in both humans and animals. However, the optimal physical variables for LLLT still lack consensus5.

Laser fluencevs intensity

In the context of the colours we can see and have available as pigments, in a subtractive colour mixing, we cover the largest mixing area as well as the largest selection of named colours by starting with a triad of cyan, magenta and yellow. Although we see a wide range of greens, missing the brightest greens has less of an impact on our perception than missing a yellow.Will you select a cyan, magenta, yellow triad for your next palette?

Values are presented as mean (standard deviation). NA: not applicable, IR5: 5 days of irradiation, IR10: 10 days of irradiation, IR15: 15 days of irradiation. *p-values are obtained by using ANOVA.

FUNDING SOURCE: This work was supported by the GRRC program of Gyeonggi province [GRRC아주2016B04, Development of medical devices using LED]. The GRRC program of Gyeonggi province had no involvement in study design; collection, analysis and interpretation of data; and writing the manuscript.

Low-level laser (light) therapy is a promising technology that stimulates healing, relieves pain and inflammation, and restores function in injured body parts. However, few studies have compared the effects of light-emitting diodes of different fluence levels or different treatment durations.

After anesthesia by intraperitoneal injection of tiletamine/zolazepam (Virbac, Seoul, Korea) and xylazine (Bayer, Seoul, Korea) which was necessary to immobilize the mice, four full-thickness wounds were created on the dorsal skin of each mouse using a 8-mm-diameter punch. The wounds were left exposed without sutures or dressings. A total of 40 mice were used to compare the effects of different irradiation fluences on wound healing. The mice were divided randomly into untreated control (group A) and treated groups (n=10 per group). The wounds of the treated groups were irradiated at fluences of 1 J/cm2 (group B), 4 J/cm2 (group C), or 40 J/cm2 (group D) for five consecutive days starting on day 1 when the wounds were made. To determine the optimal duration of treatment, 30 mice (n=10 per group) were treated with 40 J/cm2 infrared light for 5 (IR5), 10 (IR10), or 15 (IR15) consecutive days. A low-intensity LED irradiation device named SHINeY (WON TECH Co., Seoul, Korea) was used as the light source. The intensity was 100 mW/cm2 and the spot size was 4.77 mm×13.15 mm. The distance between the light source and the dorsal skin was approximately 3 cm. Nonirradiated (control) mice were maintained under similar conditions.

Laser fluencecalculator

We have shown that repeated exposure to low levels of light significantly stimulates wound healing in mice and demonstrated more efficient wound closure with certain fluences of 830 nm irradiation.

Laser fluenceand pulse duration

The basic biological mechanism behind the effects of LLLT is thought to involve the absorption of red and near-infrared light by mitochondrial chromophores, in particular cytochrome c oxidase (CCO), a component of the mitochondrial respiratory chain15,16,17. CCO activation results in increased production of adenosine triphosphate (ATP), which provides both the energy and phosphate required to regulate a variety of cellular functions. Consistent with this notion, the addition of exogenous ATP stimulated wound healing in an animal model18. Although wound contraction did not increase in mice treated with external ATP, in vitro observations suggest that ATP increases wound contraction by serving as an energy source for motility and contractile force generation, and as a phosphate donor for kinases regulating contraction19,20.

Articles from Annals of Dermatology are provided here courtesy of Korean Dermatological Association and Korean Society for Investigative Dermatology

Regarding the wound healing of human skin, not only wound closure but also prevention of hypertrophic scars and keloids have great importance. In the context of formation of hypertrophic scar, the remodeling phase has critical role. Fibroblastic proliferation and excess collagen deposits are their two main characteristics, and imbalances in the rates of collagen biosynthesis and degradation, along with individual genetic predisposition, have been implicated in their pathogenesis21. It was recently proposed that poor regulation of interleukin (IL)-6 signaling and TGF β1 expression may play a significant role in this process22,23,24,25. LLLT can decrease IL-6 mRNA levels26, and has been proposed as an alternative therapy for hypertrophic scars. In three case studies, Barolet and Boucher27 reported significant improvements to scars after LLLT following scar revision by surgery or CO2 laser ablation. In fact, the mice in our study did not show any hypertrophic scar or keloid. Therefore, it is difficult to evaluate the effectiveness of LLLT for prevention of hypertrophic scar or keloid. Through previous studies that we mentioned above, however, more than 5 days of irradiation of LLLT might be helpful to prevent formation of hypertrophic scar or keloid. Further studies to evaluate the effectiveness of LLLT for prevention of human hypertrophic scars or keloids are needed.

Low-level laser (light) therapy (LLLT) is a promising technology used in various fields to stimulate healing, relieve pain and inflammation, and restore function to injured body parts. Since the initial experiments in 1983 studying the effects of low-level HeNe laser irradiation on wounds in rats, many studies have investigated wound healing by LLLT1.

I'm not a huge fan of thinking in terms of primary colours. I find it unnecessarily restrictive. After all, you can definitely mix primary colours from secondary colours. However, in my palette building series on my youtube channel, I just recommended a Cyan, Magenta, Yellow triad as your first three colours

Laser fluenceunit

The most effective fluence level was 40 J/cm2 at day 5, as determined by monitoring wound closure. There were no statistically significant differences in wound healing with different durations.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Our eyes perceive colours with sensors (optical cones) that are each sensitive to a specific range of wavelengths of light. Different species of animals have different numbers of cones, which are sensitive to different wavelengths - bees and shrimp can see colours we can't even imagine. Humans have three cone receptors, these are sensitive to three wavelengths (or colours) of light - red, green and blue.