scholarly journals Assessment of Color Parameters on Maxillary Right Central Incisors Using Spectrophotometer and RAW Mobile Photos in Different Light Conditions

2020 ◽  
Vol 54 (4) ◽  
pp. 353-362
Author(s):  
Mirko Soldo ◽  
Davor Ileš ◽  
Robert Ćelić ◽  
Dubravka Knezović Zlatarić
Keyword(s):  
Gold Standard ◽  
Light Emitting Diode ◽  
Dental Students ◽  
Central Incisor ◽  
Light Conditions ◽  
Hybrid Filter ◽  
Light Emitting ◽  
B Values ◽  
Color Parameters ◽  
Full Power

Objectives: The aim of the study was to compare three color parameters assessed on the maxillary right central incisors using a spectrophotometer as the gold standard, along with RAW mobile calibrated and non-calibrated photos in different light conditions. Materials and methods: A total of 30 dental students participated in the study. CIE L*a*b* values were measured in the middle third of each maxillary right central incisor spectrophotometrically and digitally on RAW mobile dental photos using different light conditions (F-frontal light; L-lateral light; D-lateral light with diffusers; P- polarizing filter on frontal light; H-hybrid filter as combination of frontal light with polarizing filter and lateral lights with diffusers) with LEDs (light emitting diode) in full power, and with gray card calibration. The obtained results were compared. Results: Mean a* and b* values on calibrated, as well as mean L* values on non-calibrated RAW mobile photos did not significantly differ in different light conditions (P>0.05). CIE L*a*b* values on non-calibrated polarizing RAW mobile photos completely matched the same values obtained using a spectrophotometer on the subject’s maxillary right central incisor (P>0.05). Conclusions: Different light conditions and measuring procedures affected CIE L*a*b* values on RAW mobile photos in this study. Within the limitations, non-calibrated RAW mobile photos using a lightening device with polarizing filters on frontal LED light in standardized conditions can be a useful tool for digital dental shade determination.

scholarly journals Far-Red Light Acclimation for Improved Mass Cultivation of Cyanobacteria

Metabolites ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 170 ◽  
Author(s):  
Alla Silkina ◽  
Bethan Kultschar ◽  
Carole A. Llewellyn
Keyword(s):  
Biomass Production ◽  
White Light ◽  
Light Emitting Diode ◽  
Red Light ◽  
Industrial Biotechnology ◽  
Light Conditions ◽  
Light Emitting ◽  
Mass Cultivation ◽  
Chlorogloeopsis Fritschii ◽  
Bioactive Product

Improving mass cultivation of cyanobacteria is a goal for industrial biotechnology. In this study, the mass cultivation of the thermophilic cyanobacterium Chlorogloeopsis fritschii was assessed for biomass production under light-emitting diode white light (LEDWL), far-red light (FRL), and combined white light and far-red light (WLFRL) adaptation. The induction of chl f was confirmed at 24 h after the transfer of culture from LEDWL to FRL. Using combined light (WLFRL), chl f, a, and d, maintained the same level of concentration in comparison to FRL conditions. However, phycocyanin and xanthophylls (echinone, caloxanthin, myxoxanthin, nostoxanthin) concentration increased 2.7–4.7 times compared to LEDWL conditions. The productivity of culture was double under WLFRL compared with LEDWL conditions. No significant changes in lipid, protein, and carbohydrate concentrations were found in the two different light conditions. The results are important for informing on optimum biomass cultivation of this species for biomass production and bioactive product development.

scholarly journals Light Emitting Diode (LED) Fluorescent Microscopy: a Milestone in the Detection of Paucibacillary Mycobacterium in Case of Pulmonary Tuberculosis

1970 ◽  
Vol 40 (1) ◽  
pp. 22-26 ◽  
Author(s):  
Z Khatun ◽  
MS Hossain ◽  
CK Roy ◽  
T Sultana ◽  
MQ Rahman ◽  
...  
Keyword(s):  
Pulmonary Tuberculosis ◽  
Hiv Risk ◽  
Gold Standard ◽  
Risk Evaluation ◽  
Financial Constraints ◽  
Light Emitting Diode ◽  
Fluorescent Microscopy ◽  
Light Emitting ◽  
Fluorescent Microscope ◽  
Lowenstein Jensen

In Bangladesh with a large number of pulmonary tuberculosis cases and financial constraints with high HIV risk, evaluation of scanty i.e paucibacillary cases has great importance. To study the efficacy of Light Emitting Diode fluorescent microscopy in the diagnosis of pulmonary tuberculosis specially paucibacillary cases in comparison to conventional fluorescent microscopy, Ziehl-Neelsen staining and culture of sputum samples from patients suspected of pulmonary tuberculosis. 150 sputum samples collected from the patients suspected of pulmonary tuberculosis were processed by the Petroff's method, and subjected to Ziehl-Neelsen staining (ZN), which were examined by both LED and conventional fluorescent microscope (CFM) and culture on Lowenstein- Jensen media (gold standard) for detection of Mycobacterium tuberculosis. In this study, out of 150 patients 14.67%, 8.67%, 4% cases were detected as paucibacillary (Scanty) cases by LED, CFM, ZN respectively. LED fluorescent microscopy is more effective in the detection of paucibacillary cases of pulmonary tuberculosis than other methods of microscopic examination. DOI: http://dx.doi.org/10.3329/bmj.v40i1.9958 BMJ 2011; 40(1): 22-26

scholarly journals An Adaptive Control Approach for Light-emitting Diode Lights Can Reduce the Energy Costs of Supplemental Lighting in Greenhouses

HortScience ◽  
2017 ◽  
Vol 52 (1) ◽  
pp. 72-77 ◽  
Author(s):  
Marc W. van Iersel ◽  
David Gianino
Keyword(s):  
Duty Cycle ◽  
Light Emitting Diode ◽  
Production Costs ◽  
Photon Flux ◽  
Substantial Part ◽  
Response Curves ◽  
Light Emitting ◽  
Full Power ◽  
Supplemental Lighting ◽  
Led Lights

Supplemental lighting in greenhouses is often needed for year-round production of high-quality crops. However, the electricity needed for supplemental lighting can account for a substantial part of overall production costs. Our objective was to develop more efficient control methods for supplemental lighting, taking advantage of the dimmability of light-emitting diode (LED) grow lights. We compared 14 hours per day of full power supplemental LED lighting to two other treatments: 1) turning the LEDs on, at full power, only when the ambient photosynthetic photon flux (PPF) dropped below a specific threshold, and 2) adjusting the duty cycle of the LEDs so that the LED lights provided only enough supplemental PPF to reach a preset threshold PPF. This threshold PPF was adjusted daily from 50 to 250 μmol·m−2·s−1. Turning the LED lights on at full power and off based on a PPF threshold was not practical since this at times resulted in the lights going on and off frequently. Adjusting the duty cycle of the LED lights based on PPF measurements underneath the light bar provided excellent control of PPF, with 5-minute averages typically being within 0.2 μmol·m−2·s−1 of the threshold PPF. Continuously adjusting the duty cycle of the LED lights reduced electricity use by 20% to 92%, depending on the PPF threshold and daily light integral (DLI) from sunlight. Simulations based on net photosynthesis (An) − PPF response curves indicated that there are large differences among species in how efficiently supplemental PPF stimulates An. When there is little or no sunlight, An of Heuchera americana is expected to increase more than that of Campanula portenschlagiana when a low level of supplemental light is provided. Conversely, when ambient PPF >200 μmol·m−2·s−1, supplemental lighting will have little impact on An of H. americana, but can still results in significant increases in An of C. portenschlagiana (1.7 to 6.1 μmol·m−2·s−1 as supplemental PPF increases from 50 to 250 μmol·m−2·s−1). Adjusting the duty cycle of the LEDs based on PPF levels assures that supplemental light is provided when plants can use that supplemental light most efficiently. Implementing automated duty cycle control of LED grow lights is simple and low cost. This approach can increase the cost effectiveness of supplemental lighting, because of the associated energy savings.

Daytime Photometric Requirements for Pedestrian Signals

1997 ◽  
Vol 1605 (1) ◽  
pp. 41-48
Author(s):  
Douglas Mace ◽  
Mark Finkle ◽  
Sara Pennak
Keyword(s):  
Light Emitting Diode ◽  
Traffic Signals ◽  
Worst Case ◽  
Light Emitting ◽  
Message Testing ◽  
Pedestrian Traffic ◽  
Rectangular Signal ◽  
Display Configuration ◽  
Full Power ◽  
Pedestrian Signals

Forty-eight senior citizens participated in a field study of the visibility of letters and symbols in pedestrian traffic signals. Subjects were asked to identify signal messages from distances of 18.3 m and 29.3 m, with signal voltage set at 100 percent, 75 percent, and 50 percent of full power. Incandescent, fiber-optic, and light-emitting diode commercially available pedestrian signals were tested, including 22.9-cm and 30.5-cm rectangular signal housings and two round red-amber-green signals with symbol masks. Each subject was asked to identify the signal’s location in the test stimuli array, to name the signal’s display configuration (Walk, Don’t Walk, walking person, or hand), and to assess the signal’s brightness on a five-point scale. Analyses also were conducted on the percentage of responses about “too bright” signals and subject uncertainty about the signal message. Testing was conducted only on bright sunny days but did not include the worst-case condition of direct sunlight on the signal face. The analysis of recognition, uncertainty, and “too bright” responses suggested that a signal intensity of 25 cd minimizes the frequency of both “too bright” and uncertain responses regardless of size, distance, or technology, or whether the message is symbol or text. The data further suggest that 22.9-cm incandescent signals provide sufficient visibility with less phantom effect than 30.5-cm signals.

Molecular analysis of genes related to phenylpropanoid and ascorbate biosynthesis in salt and UV-B treated pak choi grown under LEDs

Botany ◽  
2019 ◽  
Vol 97 (9) ◽  
pp. 513-519 ◽  
Author(s):  
Young Beom Yun ◽  
Hee-Jeong Jung ◽  
Md Abdur Rahim ◽  
Jong-In Park ◽  
Yong In Kuk
Keyword(s):  
Light Emitting Diode ◽  
Phenylpropanoid Pathway ◽  
Light Conditions ◽  
Pak Choi ◽  
Light Emitting ◽  
Nutraceutical Compounds ◽  
Enhanced Production ◽  
Expression Of Genes ◽  
Significant Difference ◽  
Phenylpropanoid Biosynthesis

In this study, we measured the expression of genes related to the phenylpropanoid pathway and ascorbate oxidation by qRT-PCR to explore the mechanism of nutraceutical compounds enhancement in pak choi during stress treatments. The expression of most phenylpropanoid biosynthesis related genes (PAL, C4H, CHS, CHI, F3H1, DFR, and ANS1) was up-regulated in plants treated with NaCl, solar salt, and UV-B radiation, compared with the untreated controls under both white light and light emitting diode illumination. Moreover, CHS and ANS1 were expressed at levels 15 and 95 times higher than the untreated control. The expression of the ascorbate oxidation related gene tAPX was also up-regulated in the NaCl and UV-B treated samples compared with the control under both light conditions. By comparison, the expression of APX1 was down-regulated during the stress treatment under both light conditions. Total chlorophyll and total carotenoid contents were unaffected by the stress treatments, and there was no significant difference in the maximum quantum yield (Fv/Fm) between the stress treatments and the untreated controls. These results suggest that the expression of genes involved in phenylpropanoid biosynthesis and ascorbate oxidation correlates with the previously reported enhanced production of phenolic compounds in pak choi plants subjected to stress treatments.

scholarly journals Diagnostic efficacy of Light-Emitting Diode (LED) Fluorescence based Microscope for the diagnosis of Tuberculous lymphadenitis

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0255146
Author(s):  
Gebeyehu Assefa ◽  
Kassu Desta ◽  
Shambel Araya ◽  
Selfu Girma ◽  
Adane Mihret ◽  
...  
Keyword(s):  
Gold Standard ◽  
Light Emitting Diode ◽  
Cross Sectional Study ◽  
Comparable Efficacy ◽  
Tuberculous Lymphadenitis ◽  
Time Saving ◽  
Diagnostic Efficacy ◽  
Cross Sectional ◽  
Predictive Values ◽  
Light Emitting

Background The comparatively straightforward and cheaper light-emitting diode fluorescent microscope (LEDFM) was suggested by WHO to replace conventional microscope in tuberculosis (TB) laboratories. However, the comparable efficacy of each of those techniques differs from laboratory to laboratory. We investigated the efficacy of LEDFM for the diagnosis of tuberculous lymphadenitis (TBLN) patients. Methods A cross-sectional study was conducted on 211 samples from clinically suspected tuberculous lymphadenitis patients. Three smears were prepared from FNA on microscope slides for cytomorphology study, Auramine O (AO), and for Ziehl-Neelsen (ZN) staining. The left-over samples were inoculated onto Lowenstein-Jensen (LJ) media. Statistical analysis was done using STATA version 11. The sensitivity, specificity, positive and negative predictive values were calculated by considering the culture results as the gold standard using a 95% confidence interval. Results Among 211 samples 49.7% (105) were positive by cytomorphology, 32.7% (69) by LEDFM, 23.69% (50) by LJ culture, and 13.7% (29) by ZN. Compared to the gold standard sensitivity of ZN, LEDFM, and cytomorphology were 30% [95% CI: 17.9–44.6], 66% [95% CI: 51.2–78.8] 78% [95% CI: 64–88.5], respectively. The specificity of ZN, LEDFM, and cytomorphology was 91.3% [95% CI: 85.8–95.2], 77.6% [95% CI: 70.4–83.8], 58.8% [95% CI: 50.7–66.5], respectively. Conclusion LED fluorescence microscopy gives a legitimate option in contrast to conventional ZN techniques in terms of its higher sensitivity, a bit lower specificity, time-saving, and minimal effort.

Synchronization of Chaotic Quantum Dot Light Emitting Diodes under Optical Feedback Effect

2020 ◽  
pp. 144-148
Keyword(s):  
Quantum Dot ◽  
Delay Time ◽  
Chaos Synchronization ◽  
Optical Feedback ◽  
Light Emitting Diode ◽  
Feedback Effect ◽  
Complete Synchronization ◽  
Light Emitting ◽  
Coupling Methods ◽  
Coupling Parameters

Chaos synchronization of delayed quantum dot light emitting diode has been studied theortetically which are coupled via the unidirectional and bidirectional. at synchronization of chaotic, The dynamics is identical with delayed optical feedback for those coupling methods. Depending on the coupling parameters and delay time the system exhibits complete synchronization, . Under proper conditions, the receiver quantum dot light emitting diode can be satisfactorily synchronized with the transmitter quantum dot light emitting diode due to the optical feedback effect.

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