Comment on amt-2021-362

Background: Salvia miltiorrhiza Bunge has been used in traditional medicine. The type of light source has an effect on the growth properties and composition of functional compounds in plants. In this study, we analyzed the effects of different artificial light sources on the growth characteristics as well as antioxidant and antimicrobial activities of S. miltiorrhiza.<BR>Methods and Results: Seedlings of S. miltiorrhiza were grown under various artificial light sources, including fluorescent light (FL), light emitting diode (LED), and microwave electrodeless light (MEL), for 8 weeks. Growth characteristics were the best in plants treated with MEL. DPPH scavenging activity of the shoot was more pronounced with the FL treatments, while the roots were more active in plants grown under single wavelength lights (i.e., blue and red LEDs). Among the different light source treatments, the blue LED resulted in a higher total phenolic content in the plants. Furthermore, growing plants growth under the red LED enhanced their total flavonoid content. Notably, the antimicrobial properties of plants varied significantly between light source treatments in this study. Except for E. coli, all the tested microorganisms were susceptible to the plant extracts.<BR>Conclusions: The type of light source may be an important parameter for the enhancement of plant growth and functional compounds in S. miltiorrhiza.

Eustoma grandiflorum (Raf.) Shinn. was subjected to long-day treatment using four types of light sources with a high red (R; 660 ± 30 nm) to far-red (FR; 730 ± 30 nm) light ratio to improve cut flower quality for early-autumn shipping. The R:FR ratios of a red-light fluorescent lamp, a color fluorescent lamp (R-type), a bulb-type red-light fluorescent lamp, and a bulb-type daylight fluorescent lamp were 62.0, 100.0, 8.8, and 8.5, respectively. As a control, plants were grown under ambient daylight. Flower budding of ‘Double Pink’ seedlings, planted on July 11 and treated with night-break treatment from planting to budding using these four light sources, was delayed 2–5 days compared with the control. Night-break treatment using each light source increased the number of nodes on the main stem, number of lateral branches, and number of flower buds, and increased the cut flower length of plants at anthesis of the first floret, compared with the control. Three cultivars were treated with night break using a color fluorescent lamp (R-type) and a bulb-type red-light fluorescent lamp. Although these two light sources did not delay the flowering of ‘King of Snow’ compared with the control, the mean flowering date of ‘Double Pink’ and ‘Piccolosa Snow’ under both light sources was 3–6 days later than that of the control. These light sources increased the number of nodes of the main stem, and increased the stem length and cut flower length compared with the control in each cultivar. As the most practical application, the bulb-type red-light fluorescent lamp was used for long-day treatment of ‘Double Pink’ under four lighting periods: pre-dawn lighting for 6 h, end-of-day lighting for 6 h, all-night lighting, and night break for 6 h during the night. All-night lighting delayed flowering more than the other treatments. Cut flower length of the plants at anthesis of the first floret was longest in the pre-dawn lighting treatment. We concluded that long-day treatment using a bulb-type red-light fluorescent lamp from 0:00 to 6:00 just after planting until flower budding is most effective to improve cut flower quality for early-autumn shipping of Eustoma cultivars.

22 - LEDs for projectors

Recently, dye-sensitized solar cells demonstrated a superior performance under ambient light conditions. In this study, the influence on dye-sensitized solar cell performances was investigated under different light sources, light intensity, spectra, and water flow lens (WFL) system. Three types of light sources (xenon, halogen, and tungsten) with various spectral distributions (spectra) were used. Dyes-sensitized solar cells with varied sensitizers and co-sensitizers were tested depending on the light sources. Higher efficiency was obtained under irradiance of tungsten and halogen lamp in comparison to the xenon lamp, specifically at lower light intensities. Additionally, a new way of spectral adjustment was demonstrated. The use of a WFL system changes the distribution of spectra and remarkably influence for better performances of solar cells and efficiency values up to 30&#x0025;. The results revealed that at lower light intensity, the influence of spectra was dominant and by changing spectral distribution various values of efficiency can be obtained. Also, a great influence on solar cells characteristics had a light source used for measurements. IEEE

United States Navy submariners have historically lived with circadian disruption while at sea due to 18-h-based watchschedules. Previous research demonstrated that circadian entrainment improved with 24-h-based watchschedules. Twenty-nine male crew members participated in the study, which took place on an actual submarine patrol. The crew were exposed, first, to experimental high correlated color temperature (CCT = 13,500 K) fluorescent light sources and then to standard-issue fluorescent light sources (CCT = 4100 K). A variety of outcome measures were employed to determine if higher levels of circadian-effective light during on-watch times would further promote behavioral alignment to 24-h-based watchschedules. The high CCT light source produced significantly higher circadian light exposures than the low CCT light source, which was associated with significantly greater 24-h behavioral alignment with work schedules using phasor analysis, greater levels of sleep efficiency measured with wrist actigraphy, lower levels of subjective sleepiness measured with the Karolinska Sleepiness Scale, and higher nighttime melatonin concentrations measured by morning urinary 6-sulfatoxymelatonin/creatinine ratios. Unlike these diverse outcome measures, performance scores were significantly worse under the high CCT light source than under the low CCT light source, due to practice effects. As hypothesized, with the exception of the performance scores, all of the data converge to suggest that high CCT light sources, combined with 24-h watchschedules, promote better behavioral alignment with work schedules and greater sleep quality on submarines. Since the order and the type of light sources were confounded in this field study, the results should only be considered as consistent with our theoretical understanding of how regular, 24-h light-dark exposures combined with high circadian light exposures can promote greater behavioral alignment with work schedules and with sleep.

Abstract. The AquaVIT-4 intercomparison of atmospheric hygrometers was conducted at the AIDA (Aerosol Interaction and Dynamics in the Atmosphere) climate simulation chamber of the Karlsruhe Institute of Technology (KIT), Germany, in March–April 2022, within the framework of the HEMERA H2020 EU project. The objectives were to document the performance of existing hygrometers and to support the development of novel methods for water vapor (H2O) measurements in the upper atmosphere. The AquaVIT-4 intercomparison involved seven hygrometers based on either infrared laser absorption spectroscopy or frost-point hygrometry techniques: four deployed on aircraft or stratospheric balloon platforms and three reference instruments. The simulated conditions in the AIDA chamber reproduced the characteristic atmospheric conditions of the upper troposphere–lower stratosphere (UTLS, altitude range ∼ 5–28 km) in the tropics and midlatitudes, spanning 20–600 hPa pressure, 190–245 K temperature, and 0.5–530 ppm H2O mixing ratio. The campaign was divided into two phases, each consisting of 4 measurement days: an “open intercomparison”, where the simulated conditions were known to the participants, and a “blind intercomparison”, where the conditions were coordinated by independent referees and unknown to the participating teams. Here we present a statistical analysis of the entire dataset, which allows us to assess the accuracy and limitations of each instrument. For the accuracy evaluation, two sets of reference measurements were defined: one for in situ instruments, located inside the AIDA vessel, and one for extractive instruments, sampling the chamber gas through a heated inlet. This distinction accounts for H2O desorption effects, which are most prominent at low pressures and low H2O concentrations. All instruments showed good agreement with the reference values in the range of H2O &gt;2 ppm, with mean deviations within ± 7 % for H2O &gt;10 ppm and ± 8 % between 2–10 ppm H2O. The largest differences were found for H2O &lt;2 ppm, a rarely observed range in the atmosphere, though most of the instruments still achieved average deviations within ± 10 %. Overall, the results of AquaVIT-4 demonstrate the high accuracy and reliability of the four involved sensors for upper-atmospheric monitoring and research applications.

Development of a compact X-ray linear light source and FEL at UCLA

Recently the new type of light source has been introduced to the market. Organic light emitting diode (OLED) is not only interesting because of the low applying voltage, wide light emitting areas and emission efficiency. It gives the possibility to create a light source of a various shape, various color and in the near future very likely even the one that will change shape and spectrum in time in controlled way. Those opportunities have not been in our reach until now. In the paper authors try to give an answer to the question if the new light source -OLED - is suitable for interferometric purposes. Tests cover the short and long term spectrum stability, spectrum changes due to the emission area selection. In the paper the results of two OLEDs (red and white) are shown together with the result of an attempt to use them in an interferometric setup.

The ACT experimental station of the CAT-ACT wiggler beamline at the Karlsruhe Institute of Technology (KIT) Light Source is dedicated to the investigation of radionuclide materials with radioactivities up to 1000000 times the exemption limit by various speciation techniques applying monochromatic X-rays. In this article, the latest technological developments at the ACT station that enable high-resolution X-ray absorption near-edge structure (HR-XANES) spectroscopy for low radionuclide loading samples are highlighted – encompassing the investigation of actinide elements down to 1 p.p.m. concentration – combined with a cryogenic sample environment reducing beam-induced sample alterations. One important part of this development is a versatile gas tight plexiglass encasement ensuring that all beam paths in the five-analyzer-crystal Johann-type X-ray emission spectrometer run within He atmosphere. The setup enables the easy exchange between different experiments (conventional X-ray absorption fine structure, HR-XANES, high-energy or wide-angle X-ray scattering, tender to hard X-ray spectroscopy) and opens up the possibility for the investigation of environmental samples, such as specimens containing transuranium elements from contaminated land sites or samples from sorption and diffusion experiments to mimic the far field of a breached nuclear waste repository.

Following the worldwide interest in organic electronics ( OE ) devices, the first part of this work aimed at setting up an experimental apparatus for continuous-wave photoinduced absorption ( cw-PA ) spectroscopy with potential application to the characterization of organic photovoltaic ( OPV ) devices. This technique is part of a group known as pump- probe spectroscopy, which requires two light sources: one for pumping and the other one for probing the sample under investigation. The cw-PA spectroscopy allows the characterization of long-lasting photogenerated species in OPV s. The optical spectra of such species yield relative changes in transmission of the probe beam that are typically in the order of 10-4 . To obtain these spectra, the setup was assembled with advanced detection techniques based on a lock-in amplifier ( LIA ), with pumplight modulation at frequencies ranging from Hz to MHz. This feature makes cw-PA an important tool for the investigation of both dynamics and kinetics of photogenerated species. The setup was automated using LabView&amp;reg; and subjected to several tests to establish its reliability. After passed all the tests, the setup was applied to characterize devices with emerging architectures. One of them was the surface metal-organic frameworks ( SURMOFs ), which can form organized crystalline structure achieved with application of organic materials. After having preliminary photoconductivity results with SURMOFs based on buckminsterfullerene ( C60 ) and 5,15-bis-(3,4,5-trimethoxyphenyl)-10,20-bis(4-carboxyphe- nyl) porphyrinato zinc-II ( ZnTPP ) fabricated at Institute of Functional Interfaces ( IFG ), Karlsruhe Institute of Technology ( KIT ), in Germany, professor Wöll sent some samples to our laboratory to be further characterized. Measurements with cw-PA and current- voltage ( JV ) showed that the devices present poor charge photogeneration, with low short circuit current, open circuit voltage, and fill factor. The poor photogeneration may be caused by the low ratio acceptor/donor, while the low short circuit current, open circuit voltage, and fill factor may be caused by the assembling of C60 in a cage on ZnTPP , in which case C60 molecules are not electronically connected with each other and may be working as a sink (or trap) of electrons. Another emerging architecture named the light harvesting capacitor ( LHC ) differs from the usual OPV s because it drives an output current without charge collection. The photogenerated charges are stored in nanodipoles within the dielectric layer when the device is illuminated and the LHC outputs peaked current upon illumination by modulated light, differently from the usual photovoltaic devices. The second part of this work aimed at developing a mathematical model for LHC s as well as fabricating and characterizing an LHC . For the fabrication, the polymer poly(3- potassium-6-hexanoate thiophene) ( P3KHT ) was used as electron donor and two organic molecules, namely the N,N´-bis(6-aminohexil)-3,4,9,10-perilenediimide ( P6N ) and the perylenediimide-polyethileneimine ( PDI-PEI ) as electron acceptors. The layer-by-layer ( LbL ) assemblies led to very thin films with average thickness of ~ 1.5 nm . Results obtained from multi layer LHC s built with up to 30 active bilayers sandwiched by insulating bilayers are presented. Results from ultraviolet and visible ( UV-Vis ) spectroscopy show that the LbL technique leads to linear growth of self assembled films. Characterizations with cw-PA reveal that there is charge photogeneration with good efficiency for both types of LHC s. The photogenerated charges present average lifetime in the range 100-200 &amp;micro;s with predominantly bimolecular recombination. Regarding to charge photogeneration, LHC s based on PDI-PEI : P3KHT are found to be less efficient than those based on P6N : P3KHT . However, results from photocurrent ( PC ) measurements reveal that the photogenerated charges in LHC s based on PDI-PEI : P3KHT are more efficiently organized in aligned dipole configuration than those in LHC s based on P6N : P3KHT , indicating that PDI-PEI diffuses less into the macromolecules of P3KHT than P6N . These results for the LHC s and SURMOFs show that cw-PA is a powerful characterization technique for organic electronic devices, in combination with other electric characterization tools.

In this paper, we investigate the effect of pulse-to-pulse fluctuations of supercontinuum sources on the noise in spectral domain optical coherence tomography (OCT) images. The commonly quoted theoretical expression for the OCT noise is derived for a thermal light source, which is not suitable if a supercontinuum light source is used. We therefore propose a new, measurement-based OCT noise model that predicts the noise without any assumptions on the type of light source. We show that the predicted noise values are in excellent agreement with the measured values. The spectral correlation evaluated for the photodetected signal when using a supercontinuum determines the shape of the OCT noise floor, which must be taken into account when characterizing the sensitivity roll-off of a supercontinuum-based OCT system. The spectral correlations using both conventional supercontinuum sources and low-noise all-normal dispersion supercontinuum sources are investigated, and the fundamental physical effects that cause these correlations are discussed.

The analysis of technical characteristics and cost of modern light sources and motion sensors used in administrative premises is carried out. It has been established that lighting of corridor-type rooms using LED panels of the lower and middle price ranges with a luminous efficiency of 80-85 and 100 lm/W, accordingly, becomes less expensive in the second year of operation compared to fluorescent lighting. Installation of panels with a higher luminous efficiency, up to 120 lm/W, at the current level of prices on them has certain risks, as the payback period of the investment in this case is about 7 years, exceeding the warranty period of these panels. The payback period of investment in the automation of lighting control in corridor-type rooms using relatively inexpensive infrared motion sensors and the expected reduction of energy consumption by 30% does not exceed 5 years, demonstrating the feasibility of this event. Measures for replacing fluorescent lamps with LED panels in less loaded classrooms, up to 510 hours of operation per year, have a payback time of 4-6 years, which exceeds the warranty period of the panels. Therefore, according to the authors of the article, it is appropriate to first replace the lamps in the corridors, and then, after accumulating experience in operating the purchased light sources, to replace them in the classrooms. Due to their high cost in the premises of educational institutions, the use of presence sensors as well as automated lighting level control systems is not economically feasible. The urgency of saving energy by replacing fluorescent lamps with LED and automation of lighting control, due to the trend towards an increase in the cost of electricity, will also grow. The algorithms and formulas given in the article for determining the present value, payback periods are simple and can be applied to other types of light sources and design conditions.

Illumination design is a job that is related to culture, and forms the bridge between illumination theories on civilization and illumination theories on culture. As a result of rapid developments in illumination technology, new light sources such as LEDs are now attracting attention, and the many calls for the elimination of incandescent lamps have led to a rather alarming situation. In illumination design, various types of light sources should be used in coordination to take advantage of their unique characteristics. In this sense, LEDs and incandescent lamps are light sources that should co-exist even in the future. In illumination design, what is more important than anything else is having the mindset to learn from natural lighting.

The development of a non-invasive blood glucose monitoring system is critical in order to closely monitor the patients condition. This paper compared light emitting diode (LED) to traditional tungsten halogen lamps as a light source for glucose detection where type of light source in spectroscopy systems plays an important role in achieving a good spectrum quality. A continuous monitoring of glucose concentration has been developed as part of non-invasive technique using an optical spectroscopy. Due to the bulky tungsten halogen, there is a need to replace it with a more convenient light source such as light emitting diode (LED). Based on the results obtained, the performance of LED is similar to the tungsten halogen hence, the LED can be used as an alternative light source for simple, portable and cost effective for glucose detection application.

Simple SummaryThe increasing use of ornamental illumination has an impact on nocturnal insect communities in urban areas. The objective of this study is to verify if the selection of specific wavelengths reduces the attraction of insects towards ornamental lighting. We compared the number and diversity of insects captured onto grey sticky traps of an unilluminated area with two light sources: a metal halide lamp and a more efficient, environmentally sound prototype lamp (CromaLux) comprising a combination of green and amber LEDs. By limiting the light emitted to amber and green, the CromaLux lamps considerably reduced the attraction to the light, with similar numbers captured as in the unilluminated area, while the metal halide lamp attracted a greater number and diversity of insects.Artificial light at night (ALAN) reduces insect populations by altering their movements, foraging, reproduction, and predation. Although ALAN is mainly associated with streetlights and road networks, the ornamental illumination of monuments is making an increasing (but not well-studied) contribution. We compared insect attraction to two different types of light sources: a metal halide lamp (a type currently used to illuminate monuments) and an environmentally sound prototype lamp (CromaLux) comprising a combination of green and amber LEDs. The experiment was performed within the pilot CromaLux project in Santiago de Compostela (NW Spain). The abundance and diversity of the insects captured between June and October 2021 in the areas surrounding both light sources and in an unlit area were compared. By limiting the light emitted to amber and green, the CromaLux lamps reduced the number and diversity of insects, morphospecies, and orders attracted to the light, with similar numbers captured as in the unilluminated area, while a greater diversity of insects was captured beside the metal halide lamp. This effect has been demonstrated for almost all insect orders trapped, especially in Diptera, Lepidoptera, Coleoptera, Hemiptera, and Hymenoptera. On the contrary, Psocoptera showed a similar attraction to the CromaLux and metal halide lamps, a phenomenon whose causes deserve further investigation. As expected, Diptera were the most diverse and abundant insects in all samples, but the abundance of Lepidoptera was unexpectedly low (4%), which is in line with the worldwide evidence of the progressive decline of populations of this group. The study findings provide evidence that selecting specific wavelengths for ornamental lighting reduces the attraction of insects while maintaining adequate illumination of monuments for aesthetic purposes, resulting in a lower environmental impact on nocturnal insects. This study provides reference data for developing principles of good practices leading to possible regulatory and legal solutions and the incorporation of specific measures for artificial lighting of monuments and urban structures.