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10 LED projects for geeks : build light-up costumes, sci-fi gadgets, and other clever inventions
\"10 LED Projects for Geeks is a collection of interactive and customizable projects that all have the humble LED in common, but don't write them off as basic! You'll learn how to make challenging and imaginative gadgets like a magic wand that controls lights using hand gestures, a pen-sized controller for music synthesizers, a light strip that dances to the beat of music, and even an LED sash that flashes scrolling text you send from your phone. Every project includes photos, step-by-step directions, colorful circuit diagrams, and the complete code to bring the project to life. As you work your way through the book, you'll pick up adaptable skills that will take your making abilities to the next level. You'll learn how to: -Design versatile circuits for your own needs -Build and print a custom printed circuit board -Create flexible circuits which you can use to make any wearable you dream up -Turn analog signal into digital data your microcontroller can read -Use gesture recognition and wireless interaction for your own Internet of Things projects -Experiment with copper tape and create circuits with paper and foi -Build \"smart\" gadgets that make decisions with sensors If you want to experiment with LEDs and circuits, learn some new skills, and make cool things along the way, The 10 LED Projects for Geeks is your first step\"-- Provided by publisher.
Book
Light competition drives herbivore and nutrient effects on plant diversity
Enrichment of nutrients and loss of herbivores are assumed to cause a loss of plant diversity in grassland ecosystems because they increase plant cover, which leads to a decrease of light in the understory
1
–
3
. Empirical tests of the role of competition for light in natural systems are based on indirect evidence, and have been a topic of debate for the last 40 years. Here we show that experimentally restoring light to understory plants in a natural grassland mitigates the loss of plant diversity that is caused by either nutrient enrichment or the absence of mammalian herbivores. The initial effect of light addition on restoring diversity under fertilization was transitory and outweighed by the greater effect of herbivory on light levels, indicating that herbivory is a major factor that controls diversity, partly through light. Our results provide direct experimental evidence, in a natural system, that competition for light is a key mechanism that contributes to the loss of biodiversity after cessation of mammalian herbivory. Our findings also show that the effects of herbivores can outpace the effects of fertilization on competition for light. Management practices that target maintaining grazing by native or domestic herbivores could therefore have applications in protecting biodiversity in grassland ecosystems, because they alleviate competition for light in the understory.
Competition for light can cause plant diversity loss in grassland ecosystems when fertilized or herbivores are excluded, and experimentally restoring light can mitigate this biodiversity loss.
Journal Article
Antioxidative and Mitochondrial Protection in Retinal Pigment Epithelium: New Light Source in Action
Low-color-temperature light-emitting diodes (LEDs) (called 1900 K LEDs for short) have the potential to become a healthy light source due to their blue-free property. Our previous research demonstrated that these LEDs posed no harm to retinal cells and even protected the ocular surface. Treatment targeting the retinal pigment epithelium (RPE) is a promising direction for age-related macular degeneration (AMD). Nevertheless, no study has evaluated the protective effects of these LEDs on RPE. Therefore, we used the ARPE-19 cell line and zebrafish to explore the protective effects of 1900 K LEDs. Our results showed that the 1900 K LEDs could increase the cell vitality of ARPE-19 cells at different irradiances, with the most pronounced effect at 10 W/m2. Moreover, the protective effect increased with time. Pretreatment with 1900 K LEDs could protect the RPE from death after hydrogen peroxide (H2O2) damage by reducing reactive oxygen species (ROS) generation and mitochondrial damage caused by H2O2. In addition, we preliminarily demonstrated that irradiation with 1900 K LEDs in zebrafish did not cause retinal damage. To sum up, we provide evidence for the protective effects of 1900 K LEDs on the RPE, laying the foundation for future light therapy using these LEDs.
Journal Article
Blue light irradiation inhibits the growth of colon cancer and activation of cancer-associated fibroblasts
Irradiation with a specific wavelength of light using light-emitting diodes (LEDs) has various effects on cells and organisms. Recently, the antitumor effects of visible blue light on tumor cells were reported; however, the mechanism and effects on the tumor microenvironment remain unclear. Human colon cancer cells (HCT-116) were injected into the rectal wall of nude mice. Tumors were irradiated with a 465-nm LED light at 30 mW/cm2 for 30 min. Tumor volumes and the expression levels of opsin 3 (Opn3), autophagy-related factors, cancer-associated fibroblast (CAF) markers, and programmed cell death 1-ligand (PD-L1) were measured. Additionally, human intestinal fibroblasts were cultured in HCT116-conditioned medium (CM) to prepare CAFs. CAFs were divided into an LED group and a control group, and the effect of the LED light on CAF activation in colon cancer cells was examined. Irradiation with blue LED light suppressed tumor growth; Opn3 expression was localized to the cell membrane in the LED group. Irradiated tumors exhibited increased autophagy-related gene expression. Furthermore, in the LED group, TGF-β and α-SMA expression levels in the fibroblasts were decreased. Regarding CAFs, α-SMA and IL-6 expression levels were decreased in the LED group. HCT-116 cells cultured in CAF-CM with LED irradiation showed no enhanced migration or invasion. In the HCT-116 cells cultured in CM of CAFs irradiated with LED, the relative increase in PD-L1 expression was lower than that noted in the CAF-CM without LED irradiation. Blue LED light may have a direct antitumor effect on colon cancer and also an inhibitory effect on CAFs.
Journal Article
Enhancement of carotenoid biosynthesis in the green microalga Dunaliella salina with light-emitting diodes and adaptive laboratory evolution
There is a particularly high interest to derive carotenoids such as β-carotene and lutein from higher plants and algae for the global market. It is well known that β-carotene can be overproduced in the green microalga
Dunaliella salina
in response to stressful light conditions. However, little is known about the effects of light quality on carotenoid metabolism, e.g., narrow spectrum red light. In this study, we present UPLC-UV-MS data from
D. salina
consistent with the pathway proposed for carotenoid metabolism in the green microalga
Chlamydomonas reinhardtii
. We have studied the effect of red light-emitting diode (LED) lighting on growth rate and biomass yield and identified the optimal photon flux for
D. salina
growth. We found that the major carotenoids changed in parallel to the chlorophyll
b
content and that red light photon stress alone at high level was not capable of upregulating carotenoid accumulation presumably due to serious photodamage. We have found that combining red LED (75 %) with blue LED (25 %) allowed growth at a higher total photon flux. Additional blue light instead of red light led to increased β-carotene and lutein accumulation, and the application of long-term iterative stress (adaptive laboratory evolution) yielded strains of
D. salina
with increased accumulation of carotenoids under combined blue and red light.
Journal Article
The effect of white and green LED-lights on the catch efficiency of the Barents Sea snow crab (Chionoecetes opilio) pot fishery
In commercial snow crab (Chionoecetes opilio) fishery, the catch efficiency of the conical pots is important for increasing the profitability of the industry. This study evaluated the effect of adding green and white light emitting diodes (LED) on the catch efficiency of commercially used conical pots. The results from the field experiments showed that inserting artificial lights significantly increases the catch efficiency for snow crab over the minimum landing size of 95 mm carapace width of up to 76% when using green LED, and by 52–53% on average when using white LED. This study shows that it is possible to improve the catch efficiency of the snow crab fishery by applying artificial LED lights to the conical snow crab pots, potentially resulting in an important economic benefit to the snow crab fishery.
Journal Article
Blue light irradiation inhibits the M2 polarization of the cancer-associated macrophages in colon cancer
Recent studies have shown that blue light-emitting diode (LED) light has anti-tumor effects, suggesting the possibility of using visible light in cancer therapy. However, the effects of blue light irradiation on cells in the tumor microenvironment, including tumor-associated macrophages (TAMs), are unknown. Here, THP-1 cells were cultured in the conditioned medium (CM) of HCT-116 cells to prepare TAMs. TAMs were divided into LED-irradiated and control groups. Then, the effects of blue LED irradiation on TAM activation were examined. Expression levels of M2 macrophage markers CD163 and CD206 expression were significantly decreased in LED-irradiated TAMs compared with the control group. While control TAM-CM could induce HCT-116 cell migration, these effects were not observed in cells cultured in TAM-CM with LED irradiation. Vascular endothelial growth factor (VEGF) secretion was significantly suppressed in LED-exposed TAMs. PD-L1 expression was upregulated in HCT-116 cells cultured with TAM-CM but attenuated in cells cultured with LED-irradiated TAM-CM. In an in vivo model, protein expression levels of F4/80 and CD163, which are TAM markers, were reduced in the LED-exposed group. These results indicate that blue LED light may have an inhibitory effect on TAMs, as well as anti-tumor effects on colon cancer cells.
Journal Article
Unraveling the Role of Red:Blue LED Lights on Resource Use Efficiency and Nutritional Properties of Indoor Grown Sweet Basil
Indoor plant cultivation can result in significantly improved resource use efficiency (surface, water, and nutrients) as compared to traditional growing systems, but illumination costs are still high. LEDs (light emitting diodes) are gaining attention for indoor cultivation because of their ability to provide light of different spectra. In the light spectrum, red and blue regions are often considered the major plants' energy sources for photosynthetic CO
assimilation. This study aims at identifying the role played by red:blue (R:B) ratio on the resource use efficiency of indoor basil cultivation, linking the physiological response to light to changes in yield and nutritional properties. Basil plants were cultivated in growth chambers under five LED light regimens characterized by different R:B ratios ranging from 0.5 to 4 (respectively, RB
, RB
, RB
, RB
, and RB
), using fluorescent lamps as control (CK
). A photosynthetic photon flux density of 215 μmol m
s
was provided for 16 h per day. The greatest biomass production was associated with LED lighting as compared with fluorescent lamp. Despite a reduction in both stomatal conductance and PSII quantum efficiency, adoption of RB
resulted in higher yield and chlorophyll content, leading to improved use efficiency for water and energy. Antioxidant activity followed a spectral-response function, with optimum associated with RB
. A low RB ratio (0.5) reduced the relative content of several volatiles, as compared to CK
and RB ≥ 2. Moreover, mineral leaf concentration (g g
DW) and total content in plant (g plant
) were influences by light quality, resulting in greater N, P, K, Ca, Mg, and Fe accumulation in plants cultivated with RB
. Contrarily, nutrient use efficiency was increased in RB ≤ 1. From this study it can be concluded that a RB ratio of 3 provides optimal growing conditions for indoor cultivation of basil, fostering improved performances in terms of growth, physiological and metabolic functions, and resources use efficiency.
Journal Article
Adding Blue to Red Supplemental Light Increases Biomass and Yield of Greenhouse-Grown Tomatoes, but Only to an Optimum
Greenhouse crop production in northern countries often relies heavily on supplemental lighting for year-round yield and product quality. Among the different spectra used in supplemental lighting, red is often considered the most efficient, but plants do not develop normally when grown solely under monochromatic red light (\"red light syndrome\"). Addition of blue light has been shown to aid normal development, and typical lighting spectra in greenhouse production include a mixture of red and blue light. However, it is unclear whether sunlight, as part of the light available to plants in the greenhouse, may be sufficient as a source of blue light. In a greenhouse high-wire tomato (
), we varied the percentage of blue supplemental light (in a red background) as 0, 6, 12, and 24%, while keeping total photosynthetically active radiation constant. Light was supplied as a mixture of overhead (99 μmol m
s
) and intracanopy (48 μmol m
s
) LEDs, together with sunlight. Averaged over the whole experiment (111 days), sunlight comprised 58% of total light incident onto the crop. Total biomass, yield and number of fruits increased with the addition of blue light to an optimum, suggesting that both low (0%) and high (24%) blue light intensities were suboptimal for growth. Stem and internode lengths, as well as leaf area, decreased with increases in blue light percentage. While photosynthetic capacity increased linearly with increases in blue light percentage, photosynthesis in the low blue light treatment (0%) was not low enough to suggest the occurrence of the red light syndrome. Decreased biomass at low (0%) blue light was likely caused by decreased photosynthetic light use efficiency. Conversely, decreased biomass at high (24%) blue light was likely caused by reductions in canopy light interception. We conclude that while it is not strictly necessary to add blue light to greenhouse supplemental red light to obtain a functional crop, adding some (6-12%) blue light is advantageous for growth and yield while adding 24% blue light is suboptimal for growth.
Journal Article
The growth, nutrient uptake and fruit quality in four strawberry cultivars under different Spectra of LED supplemental light
An experiment was conducted in a greenhouse to determine the effects of different supplemental light spectra on the growth, nutrient uptake, and fruit quality of four strawberry cultivars. The plants were grown under natural light and treated with blue (460 nm), red (660 nm), and red/blue (3:1) lights. Results showed that the “Parous” and “Camarosa” had higher fresh and dry mass of leaves, roots, and crowns compared to the “Sabrina” and “Albion”. The use of artificial LED lights improved the vegetative growth of strawberry plants. All three supplemental light spectra significantly increased the early fruit yield of cultivars except for “Parous”. The red/blue supplemental light spectrum also increased the fruit mass and length of the “Albion”. Supplemental light increased the total chlorophyll in “Camarosa” and “Albion”, as well as the total soluble solids in fruits. The “Albion” had the highest concentration of fruit anthocyanin, while the “Sabrina” had the lowest. The use of supplemental light spectra significantly increased the fruit anthocyanin concentration in all cultivars. Without supplemental light, the “Camarosa” had the lowest concentration of K and Mg, which increased to the highest concentration with the use of supplemental light spectra. All three spectra increased Fe concentration to the highest value in the “Sabrina”, while only the red/blue light spectrum was effective on the “Camarosa”. In conclusion, the use of supplemental light can increase the yield and fruit quality of strawberries by elevating nutrients, chlorophyll, and anthocyanin concentrations in plants.
Journal Article