Inactivation of Escherichia coli, Salmonella enterica, and Listeria monocytogenes using the Contamination Sanitization Inspection and Disinfection (CSI-D) device

The Contamination Sanitization Inspection and Disinfection (CSI-D) device is a handheld fluorescence-based imaging system designed to disinfect food contact surfaces using ultraviolet-C (UVC) illumination. This study aimed to determine the optimal CSI-D parameters (i.e., UVC exposure time and intensity) for the inactivation of the following foodborne bacteria plated on non-selective media: generic Escherichia coli (indicator organism) and the pathogens enterohemorrhagic E. coli, enterotoxigenic E. coli, Salmonella enterica, and Listeria monocytogenes. Each bacterial strain was spread-plated on non-selective agar and exposed to high-intensity (10 mW/cm2) or low-intensity (5 mW/cm2) UVC for 1-5 s. Control plates were not exposed to UVC. The plates were incubated overnight at 37 °C and then enumerated. Three trials for each bacterial strain were conducted. Statistical analysis was carried out to determine if there were significant differences in bacterial growth between UVC intensities and exposure times. Overall, exposure to low or high intensity for 3-5 s resulted in consistent inhibition of bacterial growth, with reductions of 99.9-100 % for E. coli, 96.8-100 % for S. enterica, and 99.2-100 % for L. monocytogenes. The 1 s exposure time showed inconsistent results, with a 66.0-100 % reduction in growth depending on the intensity and bacterial strain. When the results for all strains within each species were combined, the 3-5 s exposure times showed significantly greater (p < 0.05) growth inhibition than the 1 s exposure time. However, there were no significant differences (p > 0.05) in growth inhibition between the high and low UVC intensities. The results of this study show that, in pure culture conditions, exposure to UVC with the CSI-D device for ≥3 s is required to achieve consistent reduction of E. coli, S. enterica, and L. monocytogenes.

Pre-harvest supplemental LED treatments led to improved postharvest quality of sweet basil leaves

This study determined the effects of supplemental light-emitting diode (LED) treatments on the nutrient quality and volatile compounds of sweet basil leaves during stimulated shelf-life. Basil plants were grown in a greenhouse under different supplemental LEDs (white, blue, red, or red + blue each at 100 μmol m-2 s-1), while plants grown under sunlight served as the control. The findings revealed that plant height and canopy of basil showed a significant increase under red LED irradiation, while the leaf area was improved by the blue LED exposure. Moreover, blue LEDs enhanced the levels of phenolic compounds, total phenolic contents, total flavonoid contents, and PAL (phenylalanine ammonia-lyase) activity in harvested sweet basil leaves. Additionally, red + blue LEDs lighting stimulated the production of volatile compounds. During storage, the samples treated with blue LEDs maintained a higher quality compared to the control samples. In conclusion, the application of blue or red + blue LEDs prior to harvest can be beneficial for promoting and preserving the nutritional quality of sweet basil.

Spirulina Cultivation Under Different light-emitting Diodes for Boosting Biomass and Protein Production

Microalgae biomass and pigments have a high economic value due to their many biological and commercial applications. In this sense, Spirulina platensis was grown under different (LEDs) light-emitting diodes. The current examination aims to increase the biomass production of S. platensis by formulating an optimal growth condition under different LED lights. Light-emitting diodes have a precise wavelength that has an encouraging effect on microalgae biomass production. For this purpose, the light intensity of 3000 lx was used to illuminate the culture medium, resulting in enhanced S. platensis biomass production. The highest optical density of 0.576 and dry cell weight of 0.343 g/L was recorded for the white light-emitting diode, and the red light-emitting diode, the optical density of 0.479 and dry cell weight of 0.321 g/L was recorded. The highest protein content of 66.10 ± 0.44% was registered with a blue light-emitting diode, followed by a white light-emitting diode with a protein content of 60.86 ± 0.39%. This research is an essential step in defining the light condition that might be useful to increase the biomass production of S. platensis. The study's findings demonstrated that exposure to various light-emitting diode colors could enhance both the quality and quantity of biomass produced in S. platensis cultures and encourage the use of light-emitting diodes as a light source for S. platensis farming without any undesirable effects on growth.

Optimal blue light irradiation conditions for the treatment of acne vulgaris in a mouse model

BACKGROUND

Although blue light is one of the therapeutic approaches used to treat acne vulgaris (AV), there is no consensus on its effectiveness. As a result, it is not recommended in the major acne vulgaris treatment guidelines.

OBJECTIVE

The goal of this study was to look into the mechanism, safety, and efficacy of blue light therapy. We achieved this by examining the pathological response, inflammation, and depth of light penetration in a mouse model of cystic AV.

METHODS

The aims of the study were addressed by exposing the mice to light with a wavelength of 415 nm under four different irradiation conditions. The exposure was done for five consecutive days followed by a no irradiation period of 72 h.

RESULTS

Blue light treatment was most effective when irradiation was performed at 100 mW/cm² for 20 min for five consecutive days. Inflammatory responses emerged 72 h after the final irradiation dose was administered. These responses were not associated with apoptosis as cleaved caspase-3 staining revealed no significant increases in apoptosis in the skin under any of the tested conditions. Blue light reached the superficial layer of the acne cyst at 5% of the total irradiation power and was attenuated by half for every 50 μm of progress through the cyst.

CONCLUSION

In conclusion, blue light could control severe dermatologic inflammatory responses; therefore, it can be used to irradiate AV with high inflammation levels on a daily basis until improvement is observed. In addition, porphyrin, a metabolite of Cutibacterium acnes, and reactive oxygen species generated by the surrounding skin tissue may have essential roles in AV treatment.

Photobiomodulation therapy with an 830-nm light-emitting diode for the prevention of thyroidectomy scars: a randomized, double-blind, sham device-controlled clinical trial

This randomized, double-blind, and sham device-controlled trial aimed to evaluate the efficacy and safety of home-based photobiomodulation therapy using an 830-nm light-emitting diode (LED)-based device for the prevention of and pain relief from thyroidectomy scars. Participants were randomized to receive photobiomodulation therapy using an LED device or a sham device without an LED from 1 week postoperatively for 4 weeks. Scars were assessed using satisfaction scores, the numeric rating scale (NRS) score for pain, Global Assessment Scale (GAS), and Vancouver Scar Scale (VSS) scores. The scars were also assessed using a three-dimensional (3D) skin imaging device to detect color, height, pigmentation, and vascularity. Assessments were performed at the 1-, 3-, and 6-month follow-ups. Forty-three patients completed this trial with 21 patients in the treatment group and 22 patients in the control group. The treatment group showed significantly higher patient satisfaction and GAS scores and lower NRS and VSS scores than the control group at 6 months. Improvements in color variation, height, pigmentation, and vascularity at 6 months were greater in the treatment group than in the control group, although the differences were not significant. In conclusion, early application of 830-nm LED-based photobiomodulation treatment significantly prevents hypertrophic scar formation and reduces postoperative pain without noticeable adverse effects.

Antifibrotic effects of Hypocrellin A combined with LED red light irradiation on keloid fibroblasts by counteracting the TGF-β/Smad/autophagy/apoptosis signalling pathway

Keloids are characterized by abnormal proliferation of fibroblasts and continuous deposition of extracellular matrix (ECM) components. In the field of dermopathy, photodynamic therapy (PDT) with visible light has been increasingly investigated. The natural photosensitizer Hypocrellin A (HA) was shown to have excellent light induced anticancer, antimicrobial and antiviral activities. In this experiment, we investigated the impacts of HA united light-emitting diode (LED) red light irradiation on human keloid fibroblast cells (KFs). Our results showed that HA combined with red light irradiation treatment (HA-R-PDT) decreased KF viability, reduced KF collagen production and ECM accumulation, inhibited cell proliferation, suppressed cell invasion and induced cell apoptosis. Moreover, our observations demonstrated that the TGF-β/Smad signalling pathway and autophagy were restrained by HA-R-PDT. TGF-β1 could promote autophagy in KFs through both the Smad and ERK pathways, while inhibition of autophagy altered the TGF-β1 levels through negative feedback. Therefore, HA-R-PDT suppressed cell hyperproliferation, collagen synthesis and ECM accumulation of KFs by regulating the TGF-β1-ERK-autophagy-apoptosis signalling pathway. HA-R-PDT deserves systematic investigation as a potential therapeutic strategy for keloids, and autophagy might be a promising candidate in the treatment of KFs.

The inflammation and reactive oxygen species regulated by Nrf2 and NF-κB signaling pathways in 630-nm light-emitting diode irradiation treated THP-1 monocytes/macrophages

Because of a large number of macrophages and its secreted pro-inflammatory factors in the synovial fluid of patients with rheumatoid arthritis, the present study aimed to investigate the effect and mechanism of 630-nm LED exposure on monocytes/macrophages and its anti-inflammatory effect. The THP-1 monocytes and PMA-induced THP-1 macrophages (THP-1 macrophages) were employed and irradiated by 630-nm LED for different time and times, and then measure the pro-inflammatory cytokines production by RT-qPCR and Milliplex MAP Multiplex assay, the proteins involved in inflammation pathway and reactive oxygen species (ROS) levels in the cells were detected by Western blot and DCFH-DA method. The exposure dose of red LED (15.3 J/cm², 30.6 J/cm²) were determined as no-influence on the cell proliferation, the pro-inflammatory factors TNF-α and IL-1β mRNAs, and secretions in supernatant of THP-1 macrophages were significantly decreased after LED exposure. The ROS production was blocked in THP-1 monocytes and THP-1 macrophages after treatment of LED. Finally, the phosphorylated NF-κB proteins which involved in inflammation pathway significantly decreased, and its inhibitors Nrf2 were slightly upregulated. The effects of LED anti-inflammation response are dependent on the mechanism of inhibiting ROS level and regulating NF-κB signaling pathways by increasing Nrf2 expression in the cells. It is suggested that 630-nm LED could decrease pro-inflammation in immune cells, and it may be a beneficial adjunct therapy in relieving inflammation of patients with rheumatoid arthritis.

Effects of thermal therapy combined with blue light-emitting diode irradiation on trimellitic anhydride-induced acute contact hypersensitivity mouse model

BACKGROUD

The biological effect of phototherapy, which involves using visible light for disease treatment, has attracted recent attention, especially in dermatological practice. Light-emitting diode (LED) irradiation increases dermal collagen level and reduces inflammation. It has been suggested that thermal therapy and LED irradiation can modulate inflammatory processes. However, little is known about the molecular mechanism of the anti-inflammatory effects of thermal therapy and LED irradiation.

OBJECTIVE

This study was to determine the anti-inflammatory effect of thermal therapy combined with LED irradiation on trimellitic anhydride (TMA)-induced acute contact hypersensitivity (CHS) mouse model.

METHODS

Twenty-four BALB/c mice were randomly divided into the following groups: Vehicle group, TMA group, TMA + alternating thermal therapy group (Alternating group), and TMA + alternating + LED group (LED group). Ear swelling was measured based on the thickness of ear before and after each TMA challenge. Vascular permeability was evaluated by the extravasation of Evans blue dye. Serum IgE level, Th1/Th2/Th17 cytokines, and related transcription factors were measured using ELISA kits, and histological examination was illustrated in ear tissue.

RESULTS

The LED group showed reduction in ear swelling response, vascular permeability, serum IgE levels, Th2/Th17 cytokine levels, and inflammatory cell infiltration. Moreover, the LED group showed increased Th1 cytokine levels.

CONCLUSIONS

These results indicate that thermal therapy combined with LED irradiation alleviated TMA-induced acute CHS in the mouse model. Thermal therapy and phototherapy should be considered as a novel therapeutic tool for the treatment of skin inflammation.

Blue light-emitting diode in healthy vaginal mucosa-a new therapeutic possibility

A healthy female genital mucosa has an ecosystem that remains in balance through interactions between endogenous and exogenous factors. The light-emitting diode (LED) is a device that emits light at different wavelengths, with varying color and effects. Blue light in humans is most commonly used for antimicrobial purposes and has been already applied to treat facial acne and gastric bacteria. Although blue LED therapy in humans has been reported, its properties against vaginal infections have not yet been investigated. This study aims to test the safety and effects of 401 ± 5 nm blue LED on healthy vaginal mucosa. Phase I clinical trial involving 10 women between 18 and 45 years old with healthy vaginal mucosa. The participants were illuminated by 401 ± 5 nm blue LED for 30 min and anamnesis, oncotic cytology, and pH measurement were made again after 21/28 days of treatment. In the re-evaluation, adverse effects were investigated. The mean age was 27 ± 5.4 years and one of the women was excluded due to interruption of use of oral contraceptives. Oncotic cytology done before and after therapy showed that the composition of the microflora remained normal in all participants. Vaginal pH remained unchanged in eight of the women and had a reduction in one woman (5.0-4.0). No adverse effects were observed during or after illumination. 401 ± 5 nm blue LED did not generate any adverse effects or pathogenic changes in the microflora and vaginal pH. The effects of 401 ± 5 nm blue LED still need to be tested in vulvovaginal pathogens. Trial registration number: NCT03075046.

Study of visible-light photocatalytic degradation of 2,4-dichlorophenoxy acetic acid in batch and circulated-mode photoreactors

PURPOSE

The consumption of pesticides and chemical fertilizers is one of the major environmental and health problems. In this report, 2,4-dichlorophenoxyacetic acid (2,4-D) was chosen to evaluate the impact of photodegradation using LED (Light-emitting diode) (400 and 365 nm) sources in batch and programmable circulated-mode photoreactors respectively.

METHODS

A β-cyclodextrin (β-CD) grafted titanium dioxide P25 (P25/β-CD) and complexation of 2,4-D and β-CD were synthesized via photoinduced and spray-drying methods, respectively. The structures were characterized. Moreover, we investigated the effects of the amount of catalyst, the β-CD amount on bed catalyst, irradiation time, kind of photoreactor on the photocatalytic degradation efficiency.

RESULTS

Based on the results of experiments in batch reactor, the optimum amount of TiO₂, β-CD grafted by catalyst were 1 and 0.1 g/L, respectively. In batch-mode the photodegradation efficiency of 2,4-D after 5 h with P25, P25/β-CD as a photocatalyst and 2,4-D/β-CD complex with P25 photocatalyst were approximately 81, 85 and 95% respectively. After 8 h of irradiation in circulated-mode reactor, degradation yields with P25, P25/β-CD and 2,4-D/β-CD complex along with P25 were 89, 91 and 96% respectively. On the other hand, the circulated-mode photoreactor with high efficiency was appropriate to degradation of the high concentration of 2,4-D solution (200 mg/L). After 5 successive cycles with 25 h of irradiation, P25 and P25/β-CD maintained as high 2,4-D removal efficiency as 82.6, 84% respectively, with excellent stability and reusability.

CONCLUSION

The photodegradation method can be used as an effective and environmental friendly process in the degradation of organic compound.

(3R, 3'R)-zeaxanthin protects the retina from photo-oxidative damage via modulating the inflammation and visual health molecular markers

PURPOSE

Zeaxanthin protects the macula from ocular damage due to light or radiation by scavenging harmful reactive oxygen species. In the present study, zeaxanthin product (OmniXan®; OMX), derived from paprika pods (Capsicum annum; Family-Solanaceae), was tested for its efficacy in the rat retina against photooxidation.

METHODS

Forty-two male 8-week-old Wistar rats exposed to 12L/12D, 16L/8D and 24L/0D hours of intense light conditions were orally administrated either 0 or 100 mg/kg BW of zeaxanthin concentration. Retinal morphology was analyzed by histopathology, and target gene expressions were detected with real-time polymerase chain reaction methods.

RESULTS

OMX treatment significantly increased the serum zeaxanthin concentration (p < 0.001) and ameliorated oxidative damage by increasing the antioxidant enzyme activities in the retina induced by light (p < 0.001). OMX administration significantly upregulated the expression of genes, including Rhodopsin (Rho), Rod arrestin (SAG), Gα Transducin 1 (GNAT-1), neural cell adhesion molecule (NCAM), growth-associated protein 43 (GAP43), nuclear factor-(erythroid-derived 2)-like 2 (Nrf2) and heme oxygenase (HO-1) and decreased the expression of nuclear factor-κB (NF- κB) and GFAP by OMX treatment rats. The histologic findings confirmed the antioxidant and gene expression data.

CONCLUSIONS

This study suggests that OMX is a potent substance that can be used to protect photoreceptor cell degeneration in the retina exposed to intense light.

Chlorophytum comosum-bacteria interactions for airborne benzene remediation: Effect of native endophytic Enterobacter sp. EN2 inoculation and blue-red LED light

This study was performed to determine the effect of plant-endophytic Enterobacter sp. EN2 interactions and blue-red LED light conditions on gaseous benzene removal by plants. It was found that under consecutive benzene fumigation for three cycles (18 days), inoculation of the strain EN2 into sterilized and non-sterilized native C. comosum resulted in significantly increased gaseous benzene removal compared to that in non-inoculated groups under the same light conditions (P < 0.05). Remarkably, EN2 colonization in inoculated plants under LED conditions was higher than under fluorescence conditions as the EN2 could grow better under LED conditions. Strain EN2 possesses NADPH that is used to facilitate benzene degradation and modulate plant growth under benzene stress by bacterial IAA production and ACC deaminase activity; higher IAA and lower ethylene levels were found in inoculated plants compared to non-inoculated ones. These contributed to better benzene removal efficiency. Interestingly, under fumigation for 16 cycles (67 days), there was no difference in gaseous benzene removal between inoculated plants and non-inoculated plants under the same light conditions at initial benzene concentrations of 5 ppm. This is probably due to EN2 reaching maximum growth under all treatments. However, C. comosum exhibited better benzene removal under LED conditions than under fluorescence conditions during 16 cycles, possibly due to better photosynthetic performance and plant growth, leading to more NADPH, and eventually enhanced benzene removal efficiency. Hence, the most efficient acceleration of benzene removal was provided by inoculation of strain EN2 onto C. comosum under blue-red LED light conditions.

Photobiomodulation versus light-emitting diode (LED) therapy in the treatment of temporomandibular disorder: study protocol for a randomized, controlled clinical trial

BACKGROUND

Temporomandibular disorder (TMD) is described as a subgroup of orofacial pain with a set of signs and symptoms that involve the temporomandibular joint, masticatory muscles, ears, and neck. TMD can occur unilaterally or bilaterally and approximately 70% of the population is affected with at least one sign. The disorder progresses with orofacial pain, muscle pain involving the masticatory and cervical muscles, joint noises (clicks and pops), joint block, mandibular dysfunction, and headache. The etiology can be abnormal occlusion and/or posture, trauma involving local tissues, repetitive microtrauma, parafunctional habits, and an increase in emotional stress. Studies have demonstrated that phototherapy is an efficient option for the treatment of TMD, leading to improvements in pain and orofacial function.

METHODS

The aim of the proposed study is to compare the effects of two sources of photobiomodulation in individuals with TMD. A randomized, controlled, double-blind, clinical trial is proposed, which will involve 80 individuals aged 18-65 years allocated to either a laser group or light-emitting diode (LED) group submitted to 12 sessions of phototherapy. The Research Diagnostic Criteria for TMDs will be used to evaluate all participants. Pain will be measured using the visual analog scale and maximum vertical mandibular movement will be determined with the aid of digital calipers.

DISCUSSION

This study compares the effects of two modalities of laser therapy on the pain and orofacial function of patients with TMD dysfunction. Photobiomodulation and LED therapy are treatment options for reducing the inflammatory process and pain as well as inducing the regeneration of the target tissue.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03257748 . Registered on 8 August 2017.

Light-emitting diode 585nm photomodulation inhibiting melanin synthesis and inducing autophagy in human melanocytes

BACKGROUND

Melasma is a common hyperpigmentation skin disease on face. Light-emitting diode (LED) photomodulation (585nm) is reported to be effective for the treatment of melasma. However, whether and how LED photomodulation would influence melanogenesis of human epidermal melanocytes (HEMs) is unknown.

OBJECTIVE

To evaluate the effects of LED photomodulation (585nm) on melanogenesis in HEMs.

METHODS

HEMs were irradiated with fluences of 0, 5, 10 and 20J/cm² 585nm LED light. After 5-day treatment, cell viability was analyzed by CCK-8 assay, and apoptosis was assessed by Annexin V APC assay. Melanin content and tyrosinase activity were measured by spectrophotometer. Melanosome stage and autophagosomes were determined under transmission electron microscope (TEM). The formation of autophagic punctate structures was observed under confocal microscope. RT-PCR and western blotting were used to assess the expression of relative mRNA and protein levels.

RESULTS

Yellow light LED 585nm had no effects on HEMs cell viability and apoptosis. Treatment with LED 585nm from 5J/cm² to 20J/cm² inhibited melanosome maturation, decreased melanin content and tyrosinase activity. Inhibition was accompanied by the decreased expression of tyrosinase (TYR), tyrosinase-related protein-1 (TRP-1) and microphthalmia-associated transcription factor (MITF) on both mRNA and protein levels. Autophagosomes were observed under TEM. Autophagic punctate structures of microtubule-associated protein light chain 3 (LC3) proteins were induced by LED 585nm light. The configuration change of LC3 from LC3-I to LC3-II, and the degradation of p62 protein were observed after LED 585nm. Furthermore, we also revealed that the anti-melanogenic effect of LED 585nm photomodulation was reversed by 3-Methyladenine (3-MA), which inhibits autophagy by blocking autophagosome formation via the inhibition of type III Phosphatidylinositol 3-kinases (PI-3K).

CONCLUSIONS

Our finding demonstrated that LED photomodulation with 585nm wavelength suppressed melanin content in HEMs, and the effect was caused by its dose-dependent inhibition on melanogenesis and the induction of HEMs autophagy. This may provide new insights into the efficacy of LED photomodulation in the treatment of hyperpigmentation disorders.

Effects of light sources on major flavonoids and antioxidant activity in common buckwheat sprouts

It is known that flavonoids in sprouts were accumulated more under light irradiation than under dark. Light source affecting flavonoid accumulation in sprouts is still investigating. We evaluated the effects of light sources, including red, blue and fluorescent lights, on the flavonoid accumulation and antioxidant activity in common buckwheat sprouts. Experimental results showed that blue light significantly enhanced the contents of C-glycosylflavones, including orientin, vitexin and their isomers, and rutin and a rutin isomer. Sprouts grown under blue light exhibit also the highest total phenolics and total flavonoids as well as the highest antioxidant activities. It was found that isoorientin is the highest antioxidant flavonoid whereas numerous former studies suggested that rutin is a typical antioxidant compound in common buckwheat. These results indicated that blue light could be applied for enhancing not only the content of flavonoids but also antioxidant activity in common buckwheat sprouts.

Confocal epifluorescence sensor with an arc-shaped aperture for slide-based PCR quantification

The increasing needs of point-of-care diagnostics, quarantine of epidemic pathogens, and prevention of terrorism's bio-attacks have promised the future of portable real-time quantitative polymerase chain reaction (qPCR) sensors. This work aims at developing a highly sensitive and low-cost light emitting diode (LED)-based epifluorescence sensor module for qPCR sensor development and relevant bioassay applications. Inspired by the light stop design and dark-field detection of microscopes, this paper first reports a compact confocal LED epifluorescence sensor using a light stop with an arc-shaped aperture for enhancing the flexibility of quick DNA and PCR detection. The sensor features the advantages of the dichroic mirror-free and confocal (shared-focus) characteristics, which benefits size reduction and minimal optics used. It also allows extension to integrate with in situ real-time PCR thermal cycling since the sample slide is placed apart from the epi-sensing module. The epifluorescence sensor can detect as low as sub-ng/μL standard DNA and 10¹ copies of Salmonella typhimurium InvA gene sequences (cloned in E. coli and after 30-cycle PCR) with SYBR^® Green I from non-purified culture samples, having highly sensitive and specific signal responses comparable with that of a commercial qPCR instrument.

Decrowding of lower anterior segment with and without photobiomodulation: a single center, randomized clinical trial

The aim of this study was to evaluate the effect of low-level light therapy using light-emitting diodes (LEDs) on the speed of tooth movements that were required for the leveling and aligning of the lower anterior segment during non-extraction orthodontic treatment. The sample was comprised of patients (n = 40) with lower anterior crowding who were treated with self-ligating orthodontic brackets and a standardized wire sequence. A test group of patients (n = 20) who were treated with extraoral infrared light therapy for 20 min daily with at least 80 % compliance was compared to a control group (n = 20). The date of the first arch wire placement was recorded as T1, and the date of the completion of the lower anterior segment decrowding was recorded as T2. A final impression was also taken at T2. The time between T1 and T2 was significantly reduced by 22 % in the test group compared to the control group (68.3 vs. 87.8 days, respectively, p < 0.043). The use of photobiomodulation for 20 min daily at a wavelength of 850 nm might reduce the time required to resolve lower anterior crowding. This trial and its protocol were not registered on a publicly accessible registry.

Optogenetic Engineering of Atrial Cardiomyocytes

Optogenetics is emerging in the cardiology field as a new strategy to explore biological functions through the use of light-sensitive proteins and dedicated light sources. For example, this technology allows modification of the electrophysiological properties of cardiac muscle cells with superb spatiotemporal resolution and quantitative control. In this chapter, the optogenetic modification of atrial cardiomyocytes (aCMCs) from 2-day-old Wistar rats using lentiviral vector (LV) technology and the subsequent activation of the light-sensitive proteins (i.e., ion channels) through light-emitting diodes (LEDs) are described.

Photocatalytic ozonation of pesticides in a fixed bed flow through UVA-LED photoreactor

In this study, a fixed bed flow through UVA-LED photoreactor was used to compare the efficiency of ozone, photocatalysis and photocatalysis-ozone degradation, and mineralization of two pure pesticides, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-methyl-4-chlorophenoxyacetic acid (MCPA), and a commercial one, Killex®. For the degradation of the parent compounds, ozone-based processes were more effective. While for mineralization, photocatalytic processes were more effective. Photocatalytic ozonation was the most efficient process for both the degradation and mineralization of the parent compounds. The degradation rates and mineralization by photocatalytic ozonation were higher than the summation of the corresponding rates by ozonation and photocatalysis, indicating a symbiotic relationship.Overall, the photocatalytic ozonation process with the fixed bed TiO₂ reduces the time needed for the degradation and mineralization of the pesticides, reduces the costs of powder catalyst separation and overcomes the reduced efficiency of immobilized catalysts, which makes the process quite attractive for practical applications.

Effect of light wavelength on cell growth, content of phenolic compounds and antioxidant activity in cell suspension cultures of Thevetia peruviana

Thevetia peruviana (T. peruviana) has been considered as a potentially important plant for industrial and pharmacological application. Among the number of compounds which are produced by T. peruviana, antioxidants and polyphenols are of particular interest due to their benefits on human health. Cell suspension cultures of T. peruviana were established under different conditions: 1) constant illumination (24h/day) at different light wavelengths (red, green, blue, yellow and white), 2) darkness and 3) control (12h/12h: day light/dark) to investigate their biomass, substrate uptake, polyphenols production and oxidizing activity. The results showed biomass concentrations between 17.1g dry weight (DW)/l (green light) and 18.2g DW/l (control) after 13days. The cultures that grew under green light conditions consumed completely all substrates after 10days, while other cultures required at least 13days or more. The total phenolic content was between 7.21 and 9.46mg gallic acid (GA)/g DW for all light conditions. In addition the ferric reducing antioxidant power and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid antioxidant activity ranged from 5.41-6.58mg ascorbic acid (AA)/g DW and 82.93-110.39μmol Trolox/g DW, respectively. Interestingly, the samples which grew under the darkness presented a higher phenolic content and antioxidant capacity when compared to the light conditions. All together, these results demonstrate the extraordinary effect of different lighting conditions on polyphenols production and antioxidant compounds by T. peruviana.

Blue light alters miR167 expression and microRNA-targeted auxin response factor genes in Arabidopsis thaliana plants

The effect of blue LED (450 nm) on the photomorphogenesis of Arabidopsis thaliana Col-0 plants and the transcript levels of several genes, including miRNAs, photoreceptors and auxin response factors (ARF) was investigated. It was observed that blue light accelerated the generative development, reduced the rosette leaf number, significantly reduced the leaf area, dry biomass and led to the disruption of conductive tissue formation. The blue LED differentially influenced the transcript levels of several phytochromes (PHY a, b, c, d, and e), cryptochromes (CRY 1 and 2) and phototropins (PHOT 1 and 2). At the same time, the blue LED significantly increased miR167 expression compared to a fluorescent lamp or white LEDs. This increase likely resulted in the enhanced transcription of the auxin response factor genes ARF4 and ARF8, which are regulated by this miRNA. These findings support the hypothesis that the effects of blue light on A. thaliana are mediated by auxin signalling pathway involving miRNA-dependent regulation of ARF gene expression.

Effects of light quality on main health-promoting compounds and antioxidant capacity of Chinese kale sprouts

The effects of different light qualities, including white, red and blue lights, on main health-promoting compounds and antioxidant capacity of Chinese kale sprouts were investigated using light-emitting diodes (LEDs) as a light source. Our results showed that blue light treatment significantly decreased the content of gluconapin, the primary compound for bitter flavor in shoots, while increased the glucoraphanin content in roots. Moreover, the maximum content of vitamin C was detected in the white-light grown sprouts and the highest levels of total phenolic and anthocyanins, as well as the strongest antioxidant capacity were observed in blue-light grown sprouts. Taken together, the application of a colorful light source is a good practice for improvement of the consumers' acceptance and the nutritional phtyochemicals of Chinese kale sprouts.

Frequency-modulated steady-state visual evoked potentials: a new stimulation method for brain-computer interfaces

BACKGROUND

Steady-state visual evoked potentials (SSVEPs) are widely used for brain-computer interfaces. However, users experience fatigue due to exposure to flickering stimuli. High-frequency stimulation has been proposed to reduce this problem. We adapt frequency-modulated (FM) stimulation from the auditory domain, where it is commonly used to evoke steady-state responses, and compare the EEG as well as behavioral flicker perceptibility ratings.

NEW METHOD

We evoke SSVEPs with a green light-emitting diode (LED) driven by FM signals.

RESULTS

FM-SSVEPs with different carrier and modulation frequencies can reliably be evoked with spectral peaks at the lower FM sideband. Subjective perceptibility ratings decrease with increasing FM carrier frequencies, while the peak amplitude and signal-to-noise ratio (SNR) remain the same.

COMPARISON WITH EXISTING METHOD

There are neither amplitude nor SNR differences between SSVEPs evoked rectangularly, sinusoidally or via FM. Perceptibility ratings were lower for FM-SSVEPs with carrier frequencies of 20Hz and above than for sinusoidally evoked SSVEPs.

CONCLUSIONS

FM-SSVEPs seem to be beneficial for BCI usage. Reduced flicker perceptibility in FM-SSVEPs suggests reduced fatigue, which leads to an enhanced user experience and performance.