Effects Of Different Wavelengths Research Articles

Light-induced melatonin suppression at night after exposure to different wavelength composition of morning light

Bright nocturnal light has been shown to suppress melatonin secretion. However, bright light exposure during the day might reduce light-induced melatonin suppression at night. The human circadian system is sensitive to short wavelength light. This study evaluated the preventive effect of different wavelengths of daytime light on light-induced melatonin suppression at night. Twelve male subjects were exposed to various light conditions (dim, white, and bluish white light) between the hours of 09:00 and 10:30 (daytime light conditions). They were then exposed to light (300lx) again between 01:00 and 02:30 (night-time light exposure). Subjects provided saliva samples before (00:55) and after night-time light exposure (02:30). A two-tailed paired t-test yielded significant decrements in melatonin concentrations after night-time light exposure under daytime dim and white light conditions. No significant differences were found in melatonin concentrations between pre- and post-night-time light exposure with bluish-white light. Present findings suggest that daytime blue light exposure has an acute preventive impact on light-induced melatonin suppression in individuals with a general life rhythm (sleep/wake schedule). These findings may be useful for implementing artificial light environments for humans in, for example, hospitals and underground shopping malls to reduce health risks.

Elimination of Free Radicals and Immunity Enhancement with 644 nm (Red Colour) Radiation: A Randomised Controlled Clinical Trial

Superoxide dismutase (SOD) is an important antioxidant enzyme present in all oxygen-metabolizing cells. The effect of different wavelengths on superoxide dismutase (SOD) has been reported previously which has shown to have a remarkable effect on immune system. Thus, after presenting solid scientific reasoning behind this therapeutic mode of treatment pertaining to the activity of SOD in the presence of 644 nm radiation, a randomised controlled clinical trial has been carried out which builds a unique relationship of 644 nm irradiated SOD with the elimination of free radicals and hence the enhancement of immunity, not only for curative treatment but also as a preventive tool against all those diseases related to the elimination of free radicals to get better immune system of the human body. This study was conducted in the department of Gynecology and obstetrics at Al-Khidmat Teaching Hospital Mansoorah, Lahore, Pakistan.

Behavior of Layers under Different Light Sources

Light is an important factor in the management of laying poultry. The ideal lamp spectrum that provides the best welfare conditions still needs to be determined. Wavelength and light intensity influence poultry behavior and their welfare. This study evaluated the influence of four lamps types with different light spectra on the behavior of seventy 52-week laying hens. Incandescent, fluorescent, and sodium and mercury vapor lamps were set in a different poultry house each and supplied similar light intensities. Layer behavior was video-recorded three times weekly using video cameras installed on the ceiling. The effects of different wavelengths emitted by the light sources on layer behavior were evaluated by the Kruskal-Wallis median test. Results indicated that incandescent and sodium vapor lamps increased the occurrence of nesting, and of active behaviors, such as floor-scratching and pecking.

Spectral Sensitivity of Thermally Modified and Unmodified Wood

The chemical structure of wood changes significantly during thermal modification, significantly influencing the behaviour of wood during weathering. In this study, the effect of different wavelength ranges on thermally modified and unmodified aspen (Populus tremula L.) wood during solar irradiation was investigated. Irradiation was performed by exposing wood to natural solar irradiation under filters transmitting different wavelength ranges. For both woods, the magnitude of characteristic change (discolouration, changes in reflectance, and chemical composition) clearly depended on the solar wavelength bands, but the trends of the changes differed. For unmodified wood, the magnitude of the characteristic changes increased as the portion of short-wavelength radiation in the light increased. However, UV radiation was not found to be the dominant factor influencing changes in thermally modified wood during solar irradiation. The colour and chemical structure of thermally modified wood changed substantially for all studied irradiation conditions.

Real-time measurement of platelet shape change by light scattering under riboflavin and ultraviolet light treatment.

The adoption of pathogen reduction technologies (PRTs) is considered for the implementation of safer platelet (PLT) transfusion. However, the effects of PRT treatment including irradiation with ultraviolet (UV) light on PLT shape have not yet been fully clarified. Leukoreduced PLT concentrates (PCs) were treated with riboflavin and UV light (Mirasol PRT, TerumoBCT). PLT shape and adenosine diphosphate (ADP)-induced shape change were evaluated by a light scattering method where the amplitude of the scattered signal intensity was measured as the indicator of the proportion of discoid PLTs. Using a modified fluorometer, the real-time effects of different wavelengths of UV light on PLT shape were examined over the range of 300 to 360 nm at the same dose. The proportion of discoid PLTs in the Mirasol PRT-treated PCs decreased immediately after treatment. The difference in the proportion between PRT-treated and untreated PLTs became larger with storage. Although this modification correlated significantly with the pH decrease and P-selectin expression, the Mirasol PRT-treated PLTs retained sufficient ability to undergo an ADP-induced shape change. In the study using the modified fluorometer, the proportion of discoid PLTs significantly decreased with the wavelength (< 320 nm) of irradiated UV light. Mirasol PRT treatment of PCs decreases the proportion of discoid PLTs, which seemed to be caused by the irradiation with UV light of short wavelengths (< 320 nm), not that of long wavelengths (≥ 320 nm) in the Mirasol PRT system. Modification of UV light wavelength may improve the quality of PRT-treated PCs.

A New Hydrogen-Producing Strain and Its Characterization of Hydrogen Production.

A newly isolated photo non-sulfur (PNS) bacterium was identified as Rhodopseudomonas palustris PB-Z by sequencing of 16S ribosomal DNA (rDNA) genes and phylogenetic analysis. Under vigorous stirring (240rpm), the hydrogen production performances were greatly improved: The maximum hydrogen production rate and cumulative hydrogen production increased by 188.9 ± 0.07 % and 83.0 ± 0.06%, respectively, due to the hydrogen bubbles were immediately removed from the culture medium. The effects of different wavelength of light on hydrogen production with stirring were much different from that without stirring. The ranking on the photo-hydrogen production performance was white > yellow > green > blue > red without stirring and white > yellow > blue > red > green under stirring. The best light source for hydrogen production was tungsten filament lamp. The optimum temperature was 35°C. The maximal hydrogen production rate and cumulative hydrogen production reached 78.7 ± 2.3ml/l/h and 1728.1 ± 92.7mol H2/l culture, respectively, under 35°C, 240rpm, and illumination of 4000lux. Pyruvate was one of the main sources of CO2 and has a great impact on the gas composition.

Effects of different wavelengths of light on the biology, behavior, and production of grow-out Pekin ducks

Previous research has shown that red light conditions may improve growth and decrease aggressive behaviors in chickens and turkeys; however, more recent studies suggest that blue–green light may improve production of broilers over red light. To date, no research has been conducted to examine whether different wavelengths of light have an impact on production in the Pekin duck. To determine this, we raised Pekin ducks under aviary conditions that were similar to standard commercial barns. The ducks were kept in 3 different pens: red light (approximately 625 nm), blue light (approximately 425 nm), and white light. Light sources in each pen were standardized to produce a peak energy at 1.6 × 103 μM photons/m2/s at the level of the ducks’ heads. Ducks were given ad libitum access to water and commercial duck diet, and were housed on pine shavings at a density of 0.43 m2/duck. Ducks were evaluated weekly for BW and condition and a subjective measure of the duck's anxiety levels was determined. We found that ducks housed under blue light had significantly (P < 0.01) reduced BW at every age until the end of the study (processing age; 35 d). Unlike ducks housed under red or white light, ducks housed in the blue pen showed a higher level of anxiety; while evaluators were in the pen a majority of them began panting, they were much less inquisitive than other ducks, they took longer to exhibit normal social behavior once evaluation was completed, and they frequently “swarmed” when no people were present. There were no differences in any measurements between the red and white-lighted pens. These data suggest that unlike the chicken, blue lights may be inappropriate for raising Pekin ducks in a commercial setting.

ALLIUM CEPA L. (AMARYLIDACEAE) KÖK UCU HÜCRELERİ ÜZERİNE ULTRAVİYOLE RADYASYONUN FİZYOLOJİK VE GENOTOKSİK ETKİLERİNİN ARAŞTIRILMASI

In this study the physiological and cytogenetic effects of different wave length of UV radiation (260, 320 and 400 nm) were investigated on Allium cepa. The physiologic changes investigated with the measurement of germination percentage, root length and weight gain, cytogenetic changes determined with micronucleus (MN) formation and chromosomal aberrations under a light microscope. Healthy and approximately equal sized Allium cepa bulbs were used in this study. All seeds of the control and treatment groups were germinated in tap water, and seeds of treatment groups treated with 260, 320 and 400 nm wave length of UV radiation. As a result, UV radiation treatment decreased the root length, weight gain and germination percentage and this increase were determined as inversely proportional to wavelength. UV radiation treatment also encougered various chromosomal aberrations and MN formation and this encouragement shows that DNA molecules absorb UV radiation at 260 nm wavelength as the best. As a result, we are constantly exposed UV radiation because of the sun's rays has toxic effects in certain wavelengths is demonstrated using the Allium cepa test material

The Effects of Different Wavelengths of Light-Emitting Diodes on the Expression of Reproduction-Related Genes in Goldfish Carassius auratus

We investigated the differences in the expression of the neurohormones kisspeptin (Kiss) and gonadotropin-inhibitory hormone (GnIH) and cytochrome P450 aromatase (P450arom), gonadotropin hormones (GTHs), and sex steroids in the goldfish Carassius auratus exposed to light-emitting diodes (LEDs). The expression levels of Kiss1, Kiss2, G-protein-coupled receptor 54 (GPR54), GTHs, GnIH, and P450arom were compared between the control (white light) and LED-treated goldfish. Furthermore, we measured the plasma levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The levels of Kiss1 mRNA and protein; Kiss2, GPR54, and protein; GTH mRNA; and plasma FSH and LH in the hypothalamus and cultured hypothalamus cells were significantly higher in the green and purple LED treatment groups than in the other groups. These results suggested that red LEDs inhibit the sex maturation hormones, Kiss, GPR54, GTHs, and P450arom, and that GnIH plays a role in the negative regulation of reproductive function in goldfish.

Effect of Laser Photostimulation on the Healing of Third-Degree Burn wounds in Rats

Background: Burns are one of the most common injuries in the world, most importantly during the wars, and the patients usually experience high levels of pain. Complications include both physical and psychological aspects as well as aesthetic concerns. Management comprises special strategies via specific treatment protocols. Treatment stages include: rescue and control of breathing rhythm, hemorrhage management, fracture closure, particle removal, infection control and control of body temperature. It has been suggested that laser therapy with low level energy could have a positive effect on wound healing process. Objectives: The aim of this study was to examine the effect of different wavelengths of Ga-As laser with blue (405 nm) and green (532 nm) wavelengths on the healing of third-degree burn wounds in Wistar rats. Materials and Methods: In this study, 36 male Wistar rats (8-weekold, weighting 250-300 g) were divided into three groups of equal numbers. All animals were anesthetized by intraperitoneal injections. Dorsal hairs were shaved and third-degree skin burns were created on the back of the animals by using a copper stamp. The stamp was warmed up first to 95˚C via a heater. Afterwards, the animals were randomly divided into the blue and green laser and control groups. The length and width of each wound were measured by a caliper and the area of the lesion was calculated on the first, third, seventh, tenth, fourteenth, seventeenth, and twenty-first days of the study. Six samples were taken from each group for pathobiological analysis. Results: A mild anti-inflammatory effect of blue laser was observed during acute phase, which could possibly accelerate wound healing during the first week of repair. Results of our study showed that using low-level laser therapy (LLLT) with green and blue wavelengths may accelerate the wound healing process as compared with the control group. Conclusions: The laser groups have a more rapid rate of wound contraction than the control group during the healing process of burns; however, the effect of LLLT on burn wound healing was neither statistically nor histologically significant. More studies should be performed to investigate other treatment protocols and prescriptions of soft laser to clarify its role in the treatment of wounds and burn injuries.

Effects of 660- and 980-nm low-level laser therapy on neuropathic pain relief following chronic constriction injury in rat sciatic nerve

Neuropathic pain (NP) is one of the most suffered conditions in medical disciplines. The role of reactive oxygen species (ROS) and oxidative stress in the induction of NP was studied by many researchers. Neuropathies lead to medical, social, and economic isolation of the patient, so various therapies were used to treat or reduce it. During the recent years, low-level laser therapy (LLLT) has been used in certain areas of medicine and rehabilitation. Chronic constriction injury (CCI) is a well-known model for neuropathic pain studies. In order to find the effects of different wavelengths of LLLT on the injured sciatic nerve, the present research was done. Thirty Wistar adult male rats (230-320 g) were used in this study. The animals were randomly divided into three groups (n = 10). To induce neuropathic pain for the sciatic nerve, the CCI technique was used. Low-level laser of 660 and 980 nm was used for two consecutive weeks. Thermal and mechanical hyperalgesia was done before and after surgery on days 7 and 14, respectively. Paw withdrawal thresholds were also evaluated. CCI decreased the pain threshold, whereas both wavelengths of LLLT for 2 weeks increased mechanical and thermal threshold significantly. A comparison of the mechanical and thermal threshold showed a significant difference between the therapeutic effects of the two groups that received LLLT. Based on our findings, the laser with a 660-nm wavelength had better therapeutic effects than the laser with a 980-nm wavelength, so the former one may be used for clinical application in neuropathic cases; however, it needs more future studies.

Laser applications in orthodontics.

A laser is a collimated single wavelength of light which delivers a concentrated source of energy. Soon after different types of lasers were invented, investigators began to examine the effects of different wavelengths of laser energy on oral tissues, routine dental procedures and experimental applications. Orthodontists, along with other specialist in different fields of dentistry, can now benefit from several different advantages that lasers provide during the treatment process, from the beginning of the treatment, when separators are placed, to the time of resin residues removal from the tooth surface at the end of orthodontic treatment. This article outlines some of the most common usages of laser beam in orthodontics and also provides a comparison between laser and other conventional method that were the standard of care prior to the advent of laser in this field.

Cultivo in vitro de cana-de-açúcar exposta a diferentes fontes de luz

O objetivo deste trabalho foi avaliar o efeito de diferentes comprimentos de onda no desenvolvimento in vitro de mudas de cana-de-açúcar. Explantes foram submetidos a quatro tratamentos de diodos emissores de luz (LED): 100% azul; 70% azul + 30% vermelha; 30% azul + 70% vermelha; 100% vermelha, além do controle com lâmpada fluorescente branca. As plântulas foram avaliadas quanto a: número de brotações; altura; massa de matéria fresca e seca; e conteúdo de carotenoides e das clorofilas a e b. Observou-se desmanche dos tilacoides nos cloroplastos, proporcional ao aumento na incidência de luz vermelha. O porte das mudas diminui com o aumento na incidência de luz vermelha.

Effects of UV wavelength on cell damages caused by UV irradiation in PC12 cells

Ultraviolet (UV) radiations present in sunlight are a major etiologic factor for many skin diseases and induce DNA damage through formation of cyclobutane pyrimidine dimer (CPD). This study was conducted to determine the toxicological effects of different wavelengths (250, 270, 290, and 310nm) and doses of UV radiation on cell viability, DNA structure, and DNA damage repair mechanisms in a PC12 cell system. For this, we evaluated cell viability and CPD formation. Cell survival rate was markedly decreased 24h after UV irradiation in a dose-dependent manner at all wavelengths (except at 310nm). Cell viability increased with increasing wavelength in the following order: 250<270<290<310nm. UV radiation at 250nm showed the highest cell killing ability, with a median lethal dose (LD50) of 120mJ/cm2. The LD50 gradually increased with increase in wavelength. Among the 4 wavelengths tested, the highest LD50 (6000mJ/cm2) was obtained for 310nm. CPD formation decreased substantially with increasing wavelength. Among the 4 wavelengths, the proportion of CPD formation was highest at 250nm and lowest at 310nm. On the basis of LD50 values for each wavelength, PC12 cells irradiated with UV radiation of 290nm showed maximum DNA repair ability, whereas those irradiated with the 310-nm radiation did not show any repair ability. Toxicity of UV radiation varied with wavelengths and exposure doses.

The Effect of UV-A and Various Visible Light Wavelengths Radiations on Expression Level of Escherichia coli Oxidative Enzymes in Seawater

Background: Light and photosensitizers affectthe survival of bacteria in natural environments. Also light and photosensitizers are used for disinfection of materials such as blood, blood products, and water. Objectives: The present study was aimed toinvestigate the effect of different wavelengths of visible light and UV-A on the synthesis of some oxidative stress enzymes of Escherichia coli(E. coli) in seawater. Materials and Methods: Seawater were filtered by using Whatmann No:1 filter paper, followed by sterilization in the autoclave. The E. coli W3110 strain was grown at 37 oC, centrifuged, and transferred in seawater, then methylene blue was added to the seawater samples, with the exception of control samples. The seawater samples were incubated with white, blue, green, red, and UV-A light sources. Cell extracts were prepared by sonication, and then catalase, superoxide dismutase (SOD),glutathion peroxidase(GP),and glucose-6-phosphate dehydrogenase(G-6-PD) activities were measured. Results: It was found that in all studied wavelengths with or without Methylene Blue (MB), the level of all studied enzymes decreased remarkably when compared to dark controls. It was observed that the synthesis level of SOD, glutathione peroxidase GP, and glucose 6 phosphate dehydrogenase G-6-PD in E. coli decreased significantly in red light with respect to white, blue, and green light in seawater, to which methylene blue was added. In E. coli the decrease was 13% of G-6-PD expression, 10% of GP expression, and 17% of SOD expression in red light with MB after 16-hour incubation in seawater; however, these enzymes decreased to 45%, 84%,and 71% in white light, 33%, 47%, and 54% in blue light, 53%, 53%,and 64% in green light at the same incubation hours, respectively. Also, the enzyme acitivity in red light without MB did not show a significant difference when compared to other light sources. Conclusions: It was shown in the present study that red light among visible light sources has a crucial effect in decreasing the oxidative stress enzymes in seawater containing MB.

Comparison of light-emitting diode wavelength on activity and migration of rabbit ACL cells

The purpose of this study was to evaluate the biological response and gene expression of New Zealand White Rabbit anterior cruciate ligament (ACL) fibroblasts for different wave lengths of light-emitting diode (LED) irradiation. In other words, this study was undertaken to evaluate the effects of different wavelengths of LED irradiation on cell growth, expression of extracellular matrix and growth factors, migration, and expression of actin and integrin. Proliferation assay showed that red (630 nm, 9.5 J/cm(2)) and green LED (530 nm, 9.8 J/cm(2)) irradiated cells were more increased than control group but there was no difference between the control group and the blue LED (460 nm, 27 J/cm(2)) irradiated group. Moreover, the expression of insulin-like growth factor, transforming growth factor-beta (TGF-β1), and collagen I were significantly increased in the red and green LED-irradiated group, but the expression of collagen was decreased in the blue LED-irradiated group. The results of staining showed that collagen and TGF-β1 were weaker in the control group and blue LED-irradiated cells, but stronger in the red and green LED-irradiated cells. Also, in the red and green LED-irradiated group, the expression of actin and integrin was not changed compared to the control group, but the expression of actin and integrin was decreased in the blue irradiated group. This study revealed that irradiation with a wavelength of 460 nm (blue LED) is cytotoxic to ACL cells, but irradiation with nontoxic fluencies of 530 (green LED) and 630 nm (red LED) wavelengths induced cell growth in cultured ACL cells.

Effects of wavelengths of medium-pressure ultraviolet radiation on photolyase and subsequent photoreactivation

This study aims to investigate the effect of different wavelengths (254, 266, 280 and 365 nm) in polychromatic medium-pressure (MP) UV radiation on the ability of photolyases in repairing dimers and discusses its impact on subsequent photoreactivation. Photolyase was exposed to various doses and irradiances of the UV wavelengths and the dimer repair abilities of the irradiated photolyase were determined via a spectrophotometric assay. At wavelengths below 300 nm, dimer repair rates were not influenced by the UV irradiation between 0.03 and 0.10 mW cm−2. For 365 nm, photolyase exhibited enhanced dimer repair at 0.05 mW cm−2 and then reduced dimer repair with increasing irradiance. In addition, photolyase was found to have decreasing dimer repair rates when exposed to increasing UV doses at all tested wavelengths. Lower photoreactivation levels after MP UV disinfection as compared to low-pressure (LP) UV disinfection was not attributable to a single wavelength in the polychromatic radiation, but is possibly due to the simultaneous exposure of photolyase to a broad spectrum of radiation, which led to a reduction in the dimer repair ability of photolyase. This study is the first to report the direct effects of UV radiation on photolyase enzyme. The data in the study provide some evidence for the mechanism for which MP UV disinfection suppresses photoreactivation in Escherichia coli, which has only been speculated on so far. The knowledge from this study will provide a basis upon which to investigate other enzymes involved in the repair of UV damage to DNA.

Comparison of the Effects of Different Laser Wavelengths on Implants Surfaces

Lasers have been long introduced in dentistry. Today lasers are been used for Endodontics, Periodontics, Oral Surgery as well as restorative procedures. Here, we describe the effect of different wavelengths on the implant surface.

Microalgae Production Using Wastewater: Effect of Light-Emitting Diode Wavelength on Microalgal Growth

This study investigated the use of wastewater (WW) as a culture medium for microalgae under various CO2 concentrations (i.e., 0.0375%, 1%, and 15% CO2/balanced air [Bal.air]). Total nitrogen (TN) and total phosphorous (TP) removal were experimentally measured to determine whether WW is an effective culture medium for producing microalgae and correlation with microalgal growth at the fundamental level. Using WW to produce microalgae could be a feasible alternative to biological WW treatment, due to the high efficiency of TN and TP removal (i.e., >∼90% at 15% CO2/Bal.air). The growth rate of microalgae was enhanced by nearly double under 15% CO2/Bal.air during the experimental period of 6 days. This study also investigated the effect of different wavelengths from light emitting diodes (LEDs) on microalgal growth. The optimum photosynthetic photon flux density for the microalgal growth with white flat-panel LEDs was ∼135 μmol/(m2·s) at the stage of increasing population, indicating that light intensity >135 μmol/(m2·s) would expedite photosynthesis. This study also showed that blue and red LED lighting could be selectively applied to optimize the different stages of microalgal production.

Effects of low-level laser therapy after nerve reconstruction in rat denervated soleus muscle adaptation

Peripheral nerve injury (PNI) rehabilitation remains a challenge for physical therapists because PNI effects are very disabling. Low-level laser therapy (LLLT) has been described as a physical resource that is able to influence enzymes called metallopeptidases (MMPs) associated with extracellular matrix (ECM) turnover, thus accelerating neuromuscular recovery after nerve crush injuries. However, the effects of LLLT in the treatment of severe nerve injuries and denervated slow-twitch muscles are still inconclusive. The aim of this study was to evaluate the effects of different wavelengths and energy densities of LLLT irradiation, applied to a severe nerve injury after reconstruction, on denervated slow-twitch skeletal muscle adaptation. Rats were submitted to a neurotmesis of the sciatic nerve followed by end-to-end neurorrhaphy. They received transcutaneous LLLT irradiation at the lesion site. The LLLT parameters were: wavelengths--660 or 780 nm; energy densities--10, 60 or 120 J/cm²; power--40 mW; spot--4 mm². Sciatic functional index (SFI), histological, morphometric, and zymographic analyses were performed. One-way ANOVA followed by Tukey's test was used (p≤0.05). An atrophic pattern of muscle fibers was observed in all injured groups. The MMP activity in the soleus muscle reached normal levels. On the other hand, SFI remained below normality after PNI, indicating incapacity. No difference was found among PNI groups submitted or not to LLLT in any variable. LLLT applied to the nerve post-reconstruction was ineffective in delaying degenerative changes to the slow-twitch denervated muscles and in functional recovery in rats. New studies on recovery of denervated slow-twitch muscle are necessary to support clinical practice.