Evaluation of parameters governing dark and photorepair in UVC-irradiated Escherichia coli

2022 ◽  
Author(s):  
Mostafa Maghsoodi ◽  
Grace Lowry ◽  
Ian Smith ◽  
Samuel Snow
Keyword(s):  
Escherichia Coli ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Uv Exposure ◽  
Uv Disinfection ◽  
Light Emitting ◽  
Recent Advances ◽  
Evaluation Of Parameters

After decades of UV disinfection practice and numerous studies on the potential for pathogens to undergo dark or photo-repair after UV exposure, recent advances in UV light emitting diode (LED)...

scholarly journals Comparison of standard light-emitting diode (LED) and 385 nm ultraviolet A LED (UVA-LED) for disinfection of Escherichia coli

2017 ◽  
Vol 13 (4-2) ◽  
pp. 430-437 ◽  
Author(s):  
Sameen Ahmed Malik ◽  
Tan Tian Swee ◽  
Nik Ahmad Nizam Nik Malek ◽  
Mohammed Rafiq Abdul Kadir ◽  
Takahiro Emoto ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Human Life ◽  
Light Emitting ◽  
Led Light ◽  
E Coli ◽  
Wide Range ◽  
Uva Light ◽  
Uv Lamps

UV light has become an integral part of human life especially in performing wide range of disinfection. Most of the research on UVLEDs is limited to UVC region because of comparison with mercury based UV lamps which work typically at 254 nm. Limited research is found on the use of UVA-LEDs for inactivation of microorganisms in healthcare. In this study a standard 3 mm LED has been compared with 385 nm UVA-LED for inactivation of Escherichia coli.  E. coli strains were swabbed on control, LED and UVA-LED petri dishes using cotton bud. The LED and UVA-LED samples were exposed to standard LED light and UVA light respectively for 1 h. The analysis of bacteria by determining Colony forming units (CFU) and log inactivation were carried out to calculate the number of colonies present in each sample. Result showed negligible to none disinfection properties in standard LED light. LED samples had  CFU/ml colonies compared to control which is  CFU/ml. UVA-LED samples achieved maximum inactivation and only had  CFU/ml. Log inactivation results showed that LED samples observed 0.1-log inactivation whereas the UVA-LED had significant inactivation of 3.8-log inactivation corresponding to approximately 99.99 % E. coli reduction. The results demonstrate that UVA-LED at 385 nm is capable of efficiently providing inactivation of bacteria E. coli. 

scholarly journals Suppression of “volcano” morphology and parasitic defect luminescence in AlGaN-based deep-UV light-emitting diode epitaxy

2019 ◽  
Vol 13 ◽  
pp. 102285 ◽  
Author(s):  
Chia-Yen Huang ◽  
Tsung-Yen Liu ◽  
Shih-Ming Huang ◽  
Kai-Hsiang Chang ◽  
Tsu-Ying Tai ◽  
...  
Keyword(s):  
Uv Light ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Deep Uv ◽  
Defect Luminescence

scholarly journals Chromaticity Study of Curcumin Dye Extracted from Curcuma longa L. Using for UV Light down Conversion for White Light Emitting Diode

2019 ◽  
Vol 290 ◽  
pp. 183-189
Author(s):  
Mahmood Al Shafouri ◽  
Naser Mahmoud Ahmed ◽  
Zainuriah Hassan ◽  
Munirah Abdullah Almessiere
Keyword(s):  
White Light ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Curcuma Longa ◽  
Color Temperature ◽  
Light Emitting ◽  
Chromaticity Coordinates ◽  
Major Factors ◽  
Color Rendering ◽  
Down Conversion

In thus study, Turmeric phosphor dye was extracted from Curcuma Longa L. via a simple technique using silica gel. The phosphor was used for light down-conversion of UV light for the manufacture white light emitting diode (WLED). The UV-LED was analyzed over 395nm wavelengths. The characteristics of the white light chromaticity were controlled by tuning the current and phosphor concentration. An optimum color rendering index (CRI) value of 63.4 was obtained. The chromaticity coordinates (CIE) and correlated color temperature (CCT) were measured for various currents and phosphor concentrations. The white phosphor exhibited CIE value of 0.355,0.338 and CCT of 4567 K. The concentration of phosphor and amount of applied current were confirmed to be major factors that control the intensity of white light emitted from the sample, where CIE and CRI of the emitted light steadily increased with the concentration of phosphor and current. Thus, phosphor concentration has a critical effect on conversion efficiency. Key words: Turmeric, phosphor, WLED, curcumin

scholarly journals High Sensitivity of NO Gas Sensors Based on Novel Ag-Doped ZnO Nanoflowers Enhanced with a UV Light-Emitting Diode

ACS Omega ◽  
2018 ◽  
Vol 3 (10) ◽  
pp. 13798-13807 ◽  
Author(s):  
You-Ting Tsai ◽  
Shoou-Jinn Chang ◽  
Liang-Wen Ji ◽  
Yu-Jen Hsiao ◽  
I-Tseng Tang ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Uv Light ◽  
Light Emitting Diode ◽  
High Sensitivity ◽  
Light Emitting ◽  
Doped Zno

scholarly journals Visible-Light-Driven Photocatalytic Activity of Magnetic BiOBr/SrFe12O19 Nanosheets

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 735 ◽  
Author(s):  
Taiping Xie ◽  
Jiao Hu ◽  
Jun Yang ◽  
Chenglun Liu ◽  
Longjun Xu ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Electron Microscope ◽  
Visible Light ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Active Species ◽  
Composite Catalyst ◽  
Light Emitting ◽  
Transmission Electron ◽  
Visible Light Driven

Magnetic BiOBr/SrFe12O19 nanosheets were successfully synthesized using the hydrothermal method. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and UV-visible diffused reflectance spectra (UV-DRS), and the magnetic properties were tested using a vibration sample magnetometer (VSM). The as-produced composite with an irregular flaky-shaped aggregate possesses a good anti-demagnetization ability (Hc = 861.04 G) and a high photocatalytic efficiency. Under visible light (λ > 420 nm) and UV light-emitting diode (LED) irradiation, the photodegradation rates of Rhodamine B (RhB) using BiOBr/SrFe12O19 (5 wt %) (BOB/SFO-5) after 30 min of reaction were 97% and 98%, respectively, which were higher than that using BiOBr (87%). The degradation rate of RhB using the recovered BiOBr/5 wt % SrFe12O19 (marked as BOB/SFO-5) was still more than 85% in the fifth cycle, indicating the high stability of the composite catalyst. Meanwhile, after five cycles, the magnetic properties were still as stable as before. The radical-capture experiments proved that superoxide radicals and holes were main active species in the photocatalytic degradation of RhB.

Optimization of a UV light-emitting diode based fluorescence-phase sensor

2006 ◽  
Author(s):  
A. Žukauskas ◽  
N. Kurilčik ◽  
P. Vitta ◽  
S. Juršėnas ◽  
E. Bakienė ◽  
...  
Keyword(s):  
Uv Light ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Phase Sensor

High-Power UV-Light-Emitting Diode on Sapphire

2003 ◽  
Vol 42 (Part 1, No. 2A) ◽  
pp. 400-403 ◽  
Author(s):  
Motoaki Iwaya ◽  
Shun Takanami ◽  
Atsushi Miyazaki ◽  
Yasuhiro Watanabe ◽  
Satoshi Kamiyama ◽  
...  
Keyword(s):  
High Power ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Light Emitting
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