جستجوی مقالات مرتبط با کلیدواژه « blue light » در نشریات گروه « پزشکی »

Research conducted over the years has established that artificial light at night (ALAN), particularly short wavelengths in the blue region (~400–500 nm), can disrupt the circadian rhythm, cause sleep disturbances, and lead to metabolic dysregulation. With the increasing number of people spending considerable amounts of time at home or work staring at digital screens such as smartphones, tablets, and laptops, the negative impacts of blue light are becoming more apparent. While blue wavelengths during the day can enhance attention and reaction times, they are disruptive at night and are associated with a wide range of health problems such as poor sleep quality, mental health problems, and increased risk of some cancers. The growing global concern over the detrimental effects of ALAN on human health is supported by epidemiological and experimental studies, which suggest that exposure to ALAN is associated with disorders like type 2 diabetes, obesity, and increased risk of breast and prostate cancer. Moreover, several studies have reported a connection between ALAN, night-shift work, reduced cognitive performance, and a higher likelihood of human errors. The purpose of this paper is to review the biological impacts of blue light exposure on human cognitive functions and vision quality. Additionally, studies indicating a potential link between exposure to blue light from digital screens and increased risk of breast cancer are also reviewed. However, more research is needed to fully comprehend the relationship between blue light exposure and adverse health effects, such as the risk of breast cancer.

As the use of electronic devices such as mobile phones, tablets, and computers continues to rise globally, concerns have been raised about their potential impact on human health. Exposure to high energy visible (HEV) blue light, emitted from digital screens, particularly the so-called artificial light at night (ALAN), has been associated with adverse health effects, ranging from disruption of circadian rhythms to cancer. Breast cancer incidence rates are also increasing worldwide.

This study aimed at finding a correlation between breast cancer and exposure to blue light from mobile phone.

In this retrospective matched case-control study, we aimed to investigate whether exposure to blue light from mobile phone screens is associated with an increased risk of female breast cancer. We interviewed 301 breast cancer patients (cases) and 294 controls using a standard questionnaire and performed multivariate analysis, chi-square, and Fisher’s exact tests for data analysis.

Although heavy users in the case group of our study had a statistically significant higher mean 10-year cumulative exposure to digital screens compared to the control group (7089±14985 vs 4052±12515 hours, respectively, P=0.038), our study did not find a strong relationship between exposure to HEV and development of breast cancer. 

Our findings suggest that heavy exposure to HEV blue light emitted from mobile phone screens at night might constitute a risk factor for promoting the development of breast cancer, but further large-scale cohort studies are warranted.

 Photodynamic inactivation (PDI) is a new strategy for eliminating pathogenic microorganisms, especially in infectious wounds. PDI occurs using light in combination with a photosensitizer. A new approach in PDI applies natural compounds as a photosensitizer. This study aimed to introduce brewed saffron (Crocus sativus) as a new natural photosensitizer in combination with blue light to induce a phototoxic reaction in Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) strains.

 Isolated and standard S. aureus and E. coli strains and a Candida albicans standard strain were used for PDI. Various final concentrations (2.5-10 mg/mL) of brewed saffron as a photosensitizer was employed with 15 minutes of incubation. A blue LED with 5 minutes of illumination was applied as a light source. Control and treatments were compared using the colony count method.

Using the saffron extract in combination with blue LED could induce a phototoxic reaction in Gram-negative bacteria similar to Gram-positive bacteria. After PDI, there was no significant difference between Gram-positive and Gram-negative strains in terms of cellular death. The highest phototoxic reaction in all bacteria was observed at 10 mg/mL of the final saffron concentration combined with blue light by 0.65-0.75log10 (CFU/mL) cellular death. At the concentration of 2.5 mg/mL of the extract (the lowest concentration), the highest phototoxic reaction was found in the S. aureus isolated strain by a 0.65log10 (CFU/mL) reduction.

 The brewed saffron combined with blue light induces a sub-lethal phototoxic reaction in bacteria. Accordingly, it can be suggested as a natural source for new photosensitizers.

Nowadays, there is a growing global concern over rapidly increasing screen time (smartphones, tablets, and computers). An accumulating body of evidence indicates that prolonged exposure to short-wavelength visible light (blue component) emitted from digital screens may cause cancer. The application of machine learning (ML) methods has significantly improved the accuracy of predictions in fields such as cancer susceptibility, recurrence, and survival. 

To develop an ML model for predicting the risk of breast cancer in women via several parameters related to exposure to ionizing and non-ionizing radiation.

In this analytical study, three ML models Random Forest (RF), Support Vector Machine (SVM), and Multi-Layer Perceptron Neural Network (MLPNN) were used to analyze data collected from 603 cases, including 309 breast cancer cases and 294 gender and age-matched controls. Standard face-to-face interviews were performed using a standard questionnaire for data collection. 

The examined models RF, SVM, and MLPNN performed well for correctly classifying cases with breast cancer and the healthy ones (mean sensitivity> 97.2%, mean specificity >96.4%, and average accuracy >97.1%).  

Machine learning models can be used to effectively predict the risk of breast cancer via the history of exposure to ionizing and non-ionizing radiation (including blue light and screen time issues) parameters. The performance of the developed methods is encouraging; nevertheless, further investigation is required to confirm that machine learning techniques can diagnose breast cancer with relatively high accuracies automatically.

There are documents about the biological effects of blue light radiation on different organisms. An understanding of the molecular mechanism of radiation effects on biological samples is an important event which has attracted researchers’ attention. Determining the critical dysregulated proteins of Lentinulaedodes following blue light radiation is the aim of this study.

22 differentially expressedproteins of L.edodes in response to 300 lux of blue light were extracted from the related literature. Experimental, text mining and co-expression connections between the queried proteins were assessed via the STRING database. The maps were compared and the critical proteins were identified.

Among the 21 queried proteins, six individuals including heat shock HSP70 protein, 20S proteasome subunit, 26S proteasome subunit P45, Aspartate aminotransferase, phosphopyruvate hydratase, and phosphoglucomutase were highlighted as the critical proteins in response to blue light radiation.

Thefinding indicates that protein homeostasis and glycogen synthesis are affected by blue light radiation. Due to the critical roles of proteins as enzymes and structural elements in life maintenance and involvement of glycogen synthesis in energy consumption, blue light radiation can be considered as a life promotional agent in future investigations.

In this study we evaluated the photocatalytic activity and dye degradation of blue light-activated and UV-activated carboxymethylcellulose gel containing titanium dioxide nanoparticles and compared with 40% hydrogen peroxide bleaching effect to reach to a new strategy that has most efficiency with minimal side effects. The effective concentration of carboxymethylcellulose gel containing TiO2 nanoparticles was determined. The color of the main samples was measured at first, after staining with coffee and after the bleaching process by colorimeter. E1, E2, E3 were recorded and ΔE1, ΔE2 were calculated. Samples were divided into eight groups, each containing six. In three groups, the bleaching effect of CMC gel containing TiO2 nanoparticles irradiated with UV-C was investigated after one, two, and three times exposure to the teeth. In the other three groups, the bleaching effect of CMC gel containing TiO2 nanoparticles irradiated with light cure was investigated after one, two, and three times exposure to the teeth. The results were compared with two control groups CMC and H2O2. The effective concentration of carboxymethylcellulose gel containing TiO2 nanoparticles was 20%. ΔE2  result for H2O2 control group was 6.34 and for CMC control group was 2.54. The values of ΔE2 in groups were exposed once, twice and three times to CMC gel containing TiO2 nanoparticles that were activated by UV were 3.83, 4.19, 4.42 respectively and ΔE2 results in groups were exposed once, twice and three times to CMC gel containing TiO2 nanoparticles that were activated by blue-light were 4.45, 5.03, 5.55 respectively.  The greatest value of ΔE2 belonged to the bleached group with hydrogen peroxide gel with ΔE2: 6.34 and after that related to the group activated three times with blue light with ΔE2: 5.55.  All groups except the CMC control group showed ΔE2 higher than 3.3.

ntroduction: Investigating the molecular mechanism of cellular response to light radiation has attracted many researchers’ attention. In the present study, the critically affected gene by 7.5 min blue light radiation in human keratinocytes was investigated via network analysis.

Gene expression profiles of human keratinocytes exposed to 7.5 min blue light radiation plus controls were extracted from Gene Expression Omnibus (GEO). The significant dysregulated genes plus 100 first neighbors were investigated by Cytoscape software and its applications. The central nodes of the network based on four centrality parameters were determined and discussed.

Among 6 significant dysregulated genes, 4 individuals were recognized by the STRING database. The network was constructed by using the 4 queried genes and 100 first neighbors. EGR1, STAT1, and ISG15 were identified as central nodes; however, the prominent role of EGR1 was highlighted.

EGR1 appeared as a critically affected gene after blue light irradiation. It seems that this upregulated gene is responsible for protecting human keratinocytes against stress and cancer. Therefore, the application of blue light may be accompanied by antistress effects in the human body.

In this study, we present the potential of cerium oxide nanoparticle pretreatment on ARPE-19 cells, a cell line of the Retinal Pigment Epithelium (RPE), as a therapeutic modality to cellular stresses such as low serum starvation. ARPE-19 cells were pretreated with nano-cerium oxide at a concentration of 500 µg/mL before low serum stress was induced for 24, 48, 72, and 96 hours. Starvation stress was induced by using low concentrations of Fetal Bovine Serum (FBS) media at three increments: 10%, 1%, 0.1%. Contrast images demonstrated higher cell confluence and cell integrity in cells pretreated with cerium oxide nanoparticles compared to untreated cells. Increased cell viability for cerium oxide pretreated cells was confirmed by MTS assay after 96 hours of serum starvation. By using nanoparticles to influence pathways of apoptosis, we hope to rescue ARPE-19 cells from a range of stressors, including oxidative stress, and re-establish homeostasis for the cell. Nanoparticles may represent a novel class of therapeutics for diseases of the eye, like AMD and blue-light induced oxidative stress.

Exposure to light from viewing devices at night disturbs the circadian rhythm, especially sleep. The study aimed to assess (a) extent to which smart phones are used by medical undergraduate students during bedtime and to find their quality of sleep (b) the association of quality of sleep and cell phone variables.

A cross sectional observational study was conducted among 450 medical undergraduate students. The participants completed Pittsburgh Sleep Quality Index (PSQI) questionnaire and a validated semi structured questionnaire consisting of demographic details and cell phone variables.

By dividing the subjects into three groups according to their usage (Group I <1 hour, Group II 1 to 2 hours, Group III >2 hours), Group III respondents had significant prolonged sleep latency, reduced sleep duration, sleep inefficiency and daytime sleep disturbances (P < 0.05). Lack of awareness about night shift mode, lying posture use while using phone during bedtime correlated with poor quality sleep (P < 0.05).

Awareness about the negative impact of evening exposure to viewing devices on sleep and health should be emphasized.

Substantial evidence now indicates that exposure to visible light at night can be linked to a wide spectrum of disorders  ranging from obesity to cancer. More specifically, it has been shown that exposure to short wavelengths in the blue region at night is associated with adverse health effects such as sleep problems.

This study aimed at investigating if exposure to blue light emitted fromcommonsmartphones in an environment with dim light at night alters human reaction time.

Visual reaction time (VRT) of 267 male and female university students were recorded using a simple blind computerassisted test. Volunteer university students,whoprovided their informed consent were randomly divided intotwogroups of control (N = 126 students) and intervention (N = 141 students). All participants were asked to go to bed at 23:00. Participants in the intervention group were asked to use their smartphones from 23:00 to 24:00 (watching a natural life documentary movie for 60 minutes), while the control group only stayed in bed under low lighting condition, i.e. dim light. Just before starting the experiment and after 60 minutes of smartphone use, reaction time was recorded in both groups.

The mean reaction times in the intervention and the control groups before the experiment (23:00) did not show a statistically difference (P = 0.449). The reaction time in the intervention group significantly increased from 412.64105.60 msec at 23:00 to 441.66125.78 msec at 24:00 (P = 0.0368) while in the control group, there was no statistically significant difference between the mean reaction times at 23:00 and 24:00.

To the best of the authors’ knowledge, this is the first study, which showed that exposure to blue-rich visible light emitted from widely used smartphones increases visual reaction time, which would eventually result in a delay inhumanresponses to different hazards. These findings indicate that people, such as night shift or on call workers, who need to react to stresses rapidly should avoid using their smartphones in a dim light at night.

Since the early days of human life on the Earth, our skin has been exposed to different levels of light. Recently, due to inevitable consequences of modern life, humans are not exposed to adequate levels of natural light during the day but they are overexposed to relatively high levels of artificial light at night. Skin is a major target of oxidative stress and the link between aging and oxidative stress is well documented. Especially, extrinsic skin aging can be caused by oxidative stress. The widespread use of light emitting diodes (LEDs) and the rapidly increasing use of smartphones, tablets, laptops and desktop computers have led to a significant rise in the exposure of human eyes to short-wavelength visible light. Recent studies show that exposure of human skin cells to light emitted from electronic devices, even for exposures as short as 1 hour, may cause reactive oxygen species (ROS) generation, apoptosis, and necrosis. The biological effects of exposure to short-wavelength visible light in blue region in humans and other living organisms were among our research priorities at the Ionizing and Non-ionizing Radiation Protection Research Center (INIRPRC). Today, there is a growing concern over the safety of the light sources such as LEDs with peak emissions in the blue light range (400-490 nm). Recent studies aimed at investigating the effect of exposure to light emitted from electronic device on human skin cells, shows that even short exposures can increase the generation of reactive oxygen species. However, the biological effects of either long-term or repeated exposures are not fully known, yet. Furthermore, there are reports indicating that frequent exposure to visible light spectrum of the selfie flashes may cause skin damage and accelerated skin ageing. In this paper we have addressed the different aspects of potential effects of exposure to the light emitted from smartphones’ digital screens as well as smartphones’ photoflashes on premature aging of the human skin. Specifically, the effects of blue light on eyes and skin are discussed. Based on current knowledge, it can be suggested that changing the spectral output of LED-based smartphones’ flashes can be introduced as an effective method to reduce the adverse health effects associated with exposure to blue light.

It has been shown that short-wavelength blue component of the visible light spectrum can alter the circadian rhythm and suppress the level of melatonin hormone. The short-wavelength light emitted by smartphones’ screens can affect the sleep quality of the people who use these devices at night through suppression of melatonin.
In this study, we examined the effects of covering the screens of smartphones with different filters (changing the effective wavelength of the light) on sleep delay time in 43 healthy students.
Volunteer students were asked to go to bed at 23:00 and to use their mobile phones in bed for watching a natural life documentary movie for 60 minutes. No filter was used for one night while amber and blue filters were used for other 2 nights. Photospectrometry method was used to determine the output spectrum of the light passing through the filters used for covering the screens of the mobile phones. The order for utilizing amber or blue filters or using no filter was selected randomly. After 1 hour, the participants were asked to record their sleep delay time measured by a modified form of sleep time record sheet.
The mean sleep delay time for the “no-filter” night was 20.84±9.15 minutes, while the sleep delay times for the nights with amber and blue filters were 15.26±1.04 and 26.33±1.59 minutes, respectively.
The findings obtained in this study support this hypothesis that blue light possibly suppresses the secretion of melatonin more than the longer wavelengths of the visible light spectrum. Using amber filter in this study significantly improved the sleep quality. Altogether, these findings lead us to this conclusion that blocking the short-wavelength component of the light emitted by smartphones’ screens improves human sleep.

Antirrhinum majus contains aurone with excellent antibacterial and antifungal activities. In addition, visible light activates the endogenous porphyrins of Propionibacterium acne, which results in bacterial death. Therefore, considering the above‑mentioned facts, the aim of the present study was to prepare a topical herbal gel of A. majus hydroalcoholic extract and to evaluate its antiacne effects with or without blue light combination as an activator of the porphyrins.

Antibacterial activity of the shoot or petal extracts was evaluated by disc diffusion method and the minimum inhibitory concentration (MIC) was calculated. Various gel formulations were developed by the Experimental Design software. The obtained gel formulations were prepared and tested for pharmaceutical parameters including organoleptic features, pH, viscosity, drug content, and release studies. Finally, the antibacterial activity was evaluated against (P. acnes) with or without blue light.

The MIC of the extracts showed to be 0.25 μg/ml. Evaluation of the gel formulation showed acceptable properties of the best formulation in comparison to a gel in the market. Pharmaceutical parameters were also in accordance with the standard parameters of the marketed gel. Furthermore, statistical analyses showed significant antibacterial effect for gel when compared to negative control. However, combination of blue light with gel did not show any significant difference on the observed antibacterial effect.

Because of the statistically significant in vitro antiacne effects of the formulated gel, further clinical studies for evaluation of the healing effects of the prepared gel formulation on acne lesions must be performed.

Ligation-independent cloning is a simple method that provides several advantages over conventional cloning. However, the efficiency of ligation-independent cloning is considerably lower than that of conventional methods. Several studies have shown that competent cells used for ligation-independent cloning should preferably have a transformation efficiency of 106-107 cfu/μg DNA. Although such levels can be easily achieved using standard protocols with most Escherichia coli strains, some strains attain mush lower values. When such strains have to be used for ligation-independent cloning, certain measures need to be taken to avoid any situation that may further decrease the efficiency of the process. These measures, however, are usually time-consuming. This problem is exacerbated by the fact that some strains such as BL21 (DE3) appear to be intrinsically unsuited for ligation-independent cloning. Here we suggest that by avoiding DNA damage during purification simply by replacing UV transilluminators with blue light systems BL21 (DE3) cells with a transformation efficiency of 105 cfu/μg DNA can satisfactorily be used for ligation-independent cloning without any additional steps.

Breast cancer is the most common malignancy among women, both in the developed and developing countries. Women with mutations in the BRCA1 and BRCA2 genes have an increased risk of breast and ovarian cancers. Recent studies show that short-wavelength visible light disturb the secretion of melatonin and causes circadian rhythm disruption. We have previously studied the health effects of exposure to different levels of radiofrequency electromagnetic fields (RF-EMFs) such as mobile phones, mobile base stations, mobile phone jammers, laptop computers, and radars. Moreover, over the past several years, we investigated the health effects of exposure to the short wavelength visible light in the blue region emitted from digital screens. The reduction of melatonin secretion after exposure to blue light emitted from smartphone’s screen has been reported to be associated with the negative impact of smartphone use at night on sleep. We have shown that both the blue light and RF-EMFs generated by mobile phones are linked to the disruption of the circadian rhythm in people who use their phones at night. Therefore, if women with hereditary breast cancer predispositions use their smartphones, tablets and laptops at night, disrupted circadian rhythms (suppression of melatonin caused by exposure to blue light emitted from the digital screens), amplifies the risk of breast cancer. It can be concluded that women who carry mutated BRCA1 or BRCA2, or women with family history of breast cancer should avoid using their smartphones, tablets and laptops at night. Using sunglasses with amber lenses, or smartphone applications which decrease the users’ exposure to blue light before sleep, at least to some extent, can decrease the risk of circadian rhythm disruption and breast cancer.

Due to rapid advances in modern technologies such as telecommunication technology, the world has witnessed an exponential growth in the use of digital handheld devices (e.g. smartphones and tablets). This drastic growth has resulted in increased global concerns about the safety of these devices. Smartphones, tablets, laptops, and other digital screens emit high levels of short-wavelength visible light (i.e. blue color region in the visible light spectrum).
Material and At a dark environment, Staphylococcus aureus bacteria were exposed to the light of the tablet and smartphone. The control samples were exposed to the same intensity of light generated by a conventional incandescent light bulb. The growth rate of bacteria was examined by measuring the optical density (OD) at 625 nm by using a spectrophotometer before the light exposure and after 30 to 330 minutes of light exposure.
The growth rates of bacteria in both smartphone and tablet groups were higher than that of the control group and the maximum smartphone/control and tablet/control growth ratios were observed in samples exposed to digital screens’ light for 300 min (ratios of 3.71 and 3.95, respectively).
To the best of our knowledge, this is the first study that investigates the effect of exposure to light emitted from digital screens on the proliferation of Staphylococcus aureus and its association with acne pathogenesis. Our findings show that exposure to short-wavelength visible light emitted from smartphones and tablets can increase the proliferation of Staphylococcus aureus.