scholarly journals TIPS-Naphthalene for Efficient Visible-to-UV Photon Upconversion under Sunlight and Room Light

2020 ◽  
Author(s):  
Naoyuki Harada ◽  
Yoichi Sasaki ◽  
Masanori Hosoyamada ◽  
Nobuo Kimizuka ◽  
Nobuhiro Yanai
Keyword(s):  
High Performance ◽  
Uv Light ◽  
Light Sources ◽  
Solar Simulator ◽  
Visible Absorption ◽  
Excitation Light ◽  
Uv Emission ◽  
Threshold Excitation ◽  
Weak Light ◽  
Optimized Conditions

Until now, the efficiency of triplet-triplet annihilation-based photon upconversion (TTA-UC) from visible to ultraviolet (UV) light has been limited to ca. 10% due to the absence of high-performance acceptors (emitters). Here, we present the first example of visible-to-UV TTA-UC internal efficiency <i>η</i><sub>UC</sub> beyond 20% by developing a novel UV emitter, 1,4-bis((triisopropylsilyl)ethynyl)naphthalene (TIPS-Nph), and sensitizing its triplet by a donor Ir(C6)<sub>2</sub>(acac) with strong visible absorption and weak UV absorption. Under optimized conditions, 97% of the excitation light is absorbed, the threshold excitation intensity (<i>I</i><sub>th</sub> = 1.1 mW cm<sup>−2</sup>) is lower than the solar irradiance (1.4 mW cm<sup>−2</sup> for 445 ± 5 nm), and significantly, the highest external UC efficiency <i>η</i><sub>UC,ext</sub> of 17.4% for vis-to-UV TTA-UC is achieved. Upconverted UV emission can also be obtained with weak light sources such as an AM 1.5 solar simulator and room LEDs, paving the way for a variety of solar and indoor applications.

scholarly journals TIPS-Naphthalene for Efficient Visible-to-UV Photon Upconversion under Sunlight and Room Light

2020 ◽  
Author(s):  
Naoyuki Harada ◽  
Yoichi Sasaki ◽  
Masanori Hosoyamada ◽  
Nobuo Kimizuka ◽  
Nobuhiro Yanai
Keyword(s):  
High Performance ◽  
Uv Light ◽  
Light Sources ◽  
Solar Simulator ◽  
Visible Absorption ◽  
Excitation Light ◽  
Uv Emission ◽  
Threshold Excitation ◽  
Weak Light ◽  
Optimized Conditions

Until now, the efficiency of triplet-triplet annihilation-based photon upconversion (TTA-UC) from visible to ultraviolet (UV) light has been limited to ca. 10% due to the absence of high-performance acceptors (emitters). Here, we present the first example of visible-to-UV TTA-UC internal efficiency <i>η</i><sub>UC</sub> beyond 20% by developing a novel UV emitter, 1,4-bis((triisopropylsilyl)ethynyl)naphthalene (TIPS-Nph), and sensitizing its triplet by a donor Ir(C6)<sub>2</sub>(acac) with strong visible absorption and weak UV absorption. Under optimized conditions, 97% of the excitation light is absorbed, the threshold excitation intensity (<i>I</i><sub>th</sub> = 1.1 mW cm<sup>−2</sup>) is lower than the solar irradiance (1.4 mW cm<sup>−2</sup> for 445 ± 5 nm), and significantly, the highest external UC efficiency <i>η</i><sub>UC,ext</sub> of 17.4% for vis-to-UV TTA-UC is achieved. Upconverted UV emission can also be obtained with weak light sources such as an AM 1.5 solar simulator and room LEDs, paving the way for a variety of solar and indoor applications.

An End-Type Fiber-Optic UV Sensor Covered with Mixture of Two UV Sensitive Materials

2013 ◽  
Vol 543 ◽  
pp. 265-268
Author(s):  
Ana V. Joža ◽  
Dragan Z. Stupar ◽  
Jovan S. Bajić ◽  
Bojan M. Dakić ◽  
Zoran Mijatović ◽  
...  
Keyword(s):  
Fiber Optic ◽  
Uv Light ◽  
Visible Spectrum ◽  
Light Sources ◽  
Solar Simulator ◽  
Uv Sensor ◽  
Sensor Configuration ◽  
Uv Lamp ◽  
Hot Melt ◽  
Type Fiber

An end-type fiber-optic UV sensor based on the principle of fluorescence is proposed and demonstrated. The sensor is made of large-core plastic optical fiber with one end covered with mixture of hot melt adhesive and small amount of chlorophyll. As sources of ultraviolet radiation solar simulator and UV lamp are used. Spectra on the sensor output are measured with spectrometer and compared for different UV light sources. Both hot melt adhesive and chlorophyll reacted to UV radiation. The peaks of fluorescent emission are obtained in visible spectrum in range of blue wavelengths (for hot melt adhesive) and in range of red wavelengths (for chlorophyll), which makes this sensor configuration a good solution for signal multiplexing.

scholarly journals Participation of fad and mbt Genes in Synthesis of Mycobactin in Mycobacterium smegmatis

2004 ◽  
Vol 186 (2) ◽  
pp. 374-382 ◽  
Author(s):  
B. Babbette D. LaMarca ◽  
Wenming Zhu ◽  
Jean E. L. Arceneaux ◽  
B. Rowe Byers ◽  
Michael D. Lundrigan
Keyword(s):  
Absorption Spectrum ◽  
Mutant Strain ◽  
Mycobacterium Smegmatis ◽  
High Performance ◽  
Uv Light ◽  
Iron Chelator ◽  
Resonance Spectroscopy ◽  
Wild Type ◽  
Visible Absorption ◽  
Acyl Coenzyme A

ABSTRACT Colonies of Mycobacterium smegmatis LR222 on iron-limiting (0.1 μM Fe) minimal medium agar fluoresce under UV light due to the accumulation in the cells of the deferri form of the siderophore mycobactin. Two mutants with little or no fluorescence, designated LUN8 and LUN9, were isolated by screening colonies of transposon (Tn611)-mutagenized M. smegmatis. Ferrimycobactin prepared from iron-restricted cells of the wild type had an R f of 0.62 on high-performance thin-layer chromatography (HPTLC) and a characteristic visible absorption spectrum with a peak near 450 nm. Similar extracts from LUN8 cells contained a small amount of ferrimycobactin with an R f of 0.58 on HPTLC and an absorption spectrum with the peak shifted to a wavelength lower than that of the wild-type ferrimycobactin. Nuclear magnetic resonance spectroscopy studies suggested that the LUN8 mycobactin may have an altered fatty acid side chain. Mutant strain LUN9 produced no detectable mycobactin. Neither mutant strain produced measurable amounts of excreted mycobactin, although both excreted exochelin (the mycobacterial peptido-hydroxamate siderophore), and both mutants were more sensitive than the wild-type strain to growth inhibition by the iron chelator ethylenediamine-di(o-hydroxyphenylacetic acid). The transposon insertion sites were identified, and sequence analyses of the cloned flanking chromosome regions showed that the mutated gene in LUN9 was an orthologue of the Mycobacterium tuberculosis mycobactin biosynthetic gene mbtE. The mutated gene in LUN8 had homology with M. tuberculosis fadD33 (Rv1345), a gene that may encode an acyl-coenzyme A synthase and which previously was not known to participate in synthesis of mycobactin.

Immobilization of ZnO Suspension on Glass Substrate to Remove Filtration During the Removal of Remazol Red R from Aqueous Solution

2016 ◽  
Vol 12 (6) ◽  
pp. 4127-4133
Author(s):  
Nazmul Kayes ◽  
Jalil Miah ◽  
Md. Obaidullah ◽  
Akter Hossain ◽  
Mufazzal Hossain
Keyword(s):  
Aqueous Solution ◽  
Glass Substrate ◽  
Uv Light ◽  
Aqueous Suspension ◽  
Light Irradiation ◽  
Zno Films ◽  
Light Sources ◽  
Zno Film ◽  
Semiconductor Oxides ◽  
Remazol Red

Photodegradation of textile dyes in the presence of an aqueous suspension of semiconductor oxides has been of growing interest. Although this method of destruction of dyes is efficient, the main obstacle of applying this technique in the industry is the time and cost involving separation of oxides from an aqueous suspension. In this research, an attempted was made to develop ZnO films on a glass substrate by simple immobilization method for the adsorption and photodegradation of a typical dye, Remazol Red R (RRR) from aqueous solution. Adsorption and photodegradation of  RRR were performed in the presence of glass supported ZnO film. Photodegradation of the dye was carried out by varying different parameters such as the catalyst dosage, initial concentrations of RRR, and light sources. The percentage of adsorption as well as photodegradation increased with the amount of ZnO, reaches a maximum and then decreased. Maximum degradation has been found under solar light irradiation as compared to UV-light irradiation. Removal efficiency was also found to be influenced by the pre-sonication of ZnO suspension.

scholarly journals X-ray and UV emission of the ultrashort-period, low-mass eclipsing binary system BX Trianguli

2018 ◽  
Vol 619 ◽  
pp. A138
Author(s):  
V. Perdelwitz ◽  
S. Czesla ◽  
J. Robrade ◽  
T. Pribulla ◽  
J. H. M. M. Schmitt
Keyword(s):  
Binary System ◽  
Light Curve ◽  
Binary Systems ◽  
Uv Light ◽  
Close Binary ◽  
Eclipsing Binary ◽  
X Ray ◽  
Uv Emission ◽  
Low Mass ◽  
Orbital Modulation

Context.Close binary systems provide an excellent tool for determining stellar parameters such as radii and masses with a high degree of precision. Due to the high rotational velocities, most of these systems exhibit strong signs of magnetic activity, postulated to be the underlying reason for radius inflation in many of the components. Aims.We extend the sample of low-mass binary systems with well-known X-ray properties. Methods.We analyze data from a singular XMM-Newton pointing of the close, low-mass eclipsing binary system BX Tri. The UV light curve was modeled with the eclipsing binary modeling tool PHOEBE and data acquired with the EPIC cameras was analyzed to search for hints of orbital modulation. Results.We find clear evidence of orbital modulation in the UV light curve and show that PHOEBE is fully capable of modeling data within this wavelength range. Comparison to a theoretical flux prediction based on PHOENIX models shows that the majority of UV emission is of photospheric origin. While the X-ray light curve does exhibit strong variations, the signal-to-noise ratio of the observation is insufficient for a clear detection of signs of orbital modulation. There is evidence of a Neupert-like correlation between UV and X-ray data.

Electrically driven single microribbon based near-infrared exciton-polariton light-emitting diode

CrystEngComm ◽  
2021 ◽  
Author(s):  
Mingming Jiang ◽  
Fupeng Zhang ◽  
Kai Tang ◽  
Peng Wan ◽  
Caixia Kan
Keyword(s):  
High Performance ◽  
Near Infrared ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Light Sources ◽  
Coherent Light ◽  
Light Emitting ◽  
Exciton Polaritons ◽  
Laser Devices

Achieving electrically-driven exciton-polaritons has drawn substantial attention toward developing ultralow-threshold coherent light sources, containing polariton laser devices and high-performance light-emitting diodes (LEDs). In this work, we demonstrate an electrically driven...

scholarly journals Photocatalytic techniques to prevent and combat healthcare associated infections

2019 ◽  
Vol 111 ◽  
pp. 04046
Author(s):  
Răzvan Bucureşteanu ◽  
Roxana Apetrei ◽  
Monica Ioniţă ◽  
Ludmila-Otilia Cinteză ◽  
Lia-Mara Diţu ◽  
...  
Keyword(s):  
Light Output ◽  
Antimicrobial Effect ◽  
Light Sources ◽  
Healthcare Associated Infections ◽  
Excitation Light ◽  
Disinfection Process ◽  
Type Semiconductor ◽  
Healthcare Associated ◽  
Areas Of Interest ◽  
Air Circulation

An ever-increasing rate of morbidity and mortality caused by healthcare associated infections is reported annually. Air circulation mediates contact with microbial contaminated aerosols and represents a major risk of transmitting healthcare associated infections. We propose a revolutionary technique for the protection of interior surfaces based on a photocatalytic composition with doped TiO2 or ZnO type semiconductor metal oxides which exert antimicrobial effect. In principle, there is an activation of the photocatalytic coating with light from the normal lighting apparatus, which may incorporate one or more sources of photocatalytic excitation light. By studying the air circulation in the hospital, it is possible to design light fixtures with specific design of light distribution, in order to perform the disinfection of the air and surfaces and to amplify the antimicrobial effect. The disinfection process does not affect patients or healthcare professionals, it can be done in their presence and has a continuous, controllable effect. Photocatalytic paint in combination with a prototype luminaire with a precise spectrum light sources, light output and a light intensity distribution curve relative to the shape and dimensions of the rooms, shows that the proposed method may represent a successful alternative to classical methods of disinfection in hospitals. This technique can also be used in other areas of interest.

Patulin Surveillance in Apple Cider and Juice Marketed in Michigan

2009 ◽  
Vol 72 (6) ◽  
pp. 1255-1261 ◽  
Author(s):  
KERRI L. HARRIS ◽  
GERD BOBE ◽  
LESLIE D. BOURQUIN
Keyword(s):  
High Performance ◽  
Apple Juice ◽  
Solid Phase ◽  
Uv Light ◽  
Grocery Store ◽  
Grocery Stores ◽  
Apple Cider ◽  
Shelf Stable ◽  
Retail Grocery

Patulin is the most common mycotoxin found in apples and apple juices. The objective of this study was to determine the concentrations of patulin in (i) apple cider produced and marketed by Michigan apple cider mills during the fall seasons of 2002 to 2003 and 2003 to 2004 and (ii) apple juice and cider, including shelf-stable products, marketed in retail grocery stores in Michigan throughout 2005 and 2006. End product samples (n = 493) obtained from 104 Michigan apple cider mills were analyzed for patulin concentration by using solid-phase extraction followed by high-performance liquid chromatography. Patulin was detected (≥4 μg/liter) in 18.7% of all cider mill samples, with 11 samples (2.2%) having patulin concentrations of ≥50 μg/liter. A greater percentage of cider samples obtained from mills using thermal pasteurization contained detectable patulin (28.4%) than did those from mills using UV light radiation (13.5%) or no pathogen reduction treatment (17.0%). Among retail grocery store samples (n = 159), 23% of apple juice and cider samples contained detectable patulin, with 18 samples (11.3%) having patulin concentrations of ≥50 μg/liter. The U.S. Food and Drug Administration (FDA) action level for patulin is 50 μg/kg. Some apple juice samples obtained from retail grocery stores had exceptionally high patulin concentrations, ranging up to 2,700 μg/liter. Collectively, these results indicate that most apple cider and juice test samples from Michigan were below the FDA action level for patulin but that certain apple cider and juice processors have inadequate controls over patulin concentrations in final products. The industry, overall, should focus on improved quality of fruit used in juice production and improve culling procedures to reduce patulin concentrations.

scholarly journals SIMULTANEOUS DETERMINATION OF DIPHENHYDRAMINE, EPHEDRINE, NOSCAPINE, AND GLYCEROL GLYCOLATE USING STABILITY-INDICATING HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY: APPLICATION TO NOSCOF TABLETS

2019 ◽  
pp. 505-511
Author(s):  
PULAGURTHA BHASKARARAO ◽  
GOWRI SANKAR DANNANA
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Uv Light ◽  
Reversed Phase ◽  
Hplc Method ◽  
Stability Indicating ◽  
Rp Hplc ◽  
Relative Standard ◽  
Validation Parameters

Objective: Noscof tablet is a fixed dosage combination formulation having diphenhydramine (DH), ephedrine (ED), noscapine (NP), and glycerol glycolate (GG). A sensitive, selective, accurate, precise, and stability-indicating reversed-phase high-performance liquid chromatography (RP-HPLC) method with photodiode array detection has been developed and validated for simultaneous analysis of DH, ED, NP, and GG in bulk drug and Noscof tablets. Methods: Reversed-phase chromatographic separation and analysis of DH, ED, NP, and GG were done on an Altima C18 column with 0.01 M KH2PO4 buffer (pH 3.5) and acetonitrile (50:50%, v/v) as mobile phase at 0.8 ml/min flow rate in isocratic mode. Detection was performed at 260 nm. The method was validated in harmony with International Conference on Harmonization (ICH) guidelines. The tablet sample solution was subjected to diverse stress conditions using ICH strategy such as hydrolytic degradation (neutral - with distilled water, alkaline - with 2 N NaOH, and acidic - with 2 N HCl), oxidation (with 10% H2O2), photodegradation (exposing to UV light), and dry heat degradation (exposing to 105°C). Results: Using the above stated chromatographic conditions, sharp peaks were obtained for ED, NP, DH, and GG with retention time of 3.272 min, 4.098 min, 5.467 min, and 6.783 min, respectively. Good regression coefficient values were obtained in the range of 2–12 μg/ml for ED, 3.75–22.5 μg/ml for NP, 3.125–18.75 μg/ml for DH, and 25–150 μg/ml for GG. The quantification limits were 0.181 μg/ml, 0.187 μg/ml, 0.246 μg/ml, and 1.114 μg/ml for ED, NP, DH, and GG, respectively. The values of validation parameters are within the acceptance limits given by ICH. The ED, NP, DH, and GG showed more percent of degradation in acid condition and less percent of degradation in the neutral condition. The peaks of degradants did not interfere with the peaks of analytes. ED, NP, DH, and GG were assessed with a good percentage of the assay (near to 100%) and low percent relative standard deviation (<2%) in Noscof tablets using the proposed method. Conclusion: The stability indicating RP-HPLC method developed was suitable for quantifying ED, NP, DH, and GG simultaneously in bulk as well as in tablet formulation.

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