Read by QxMD icon Read

Light-emitting diodes

Amer Z Nahas, Said A Samara, Tannaz A Rastegar-Lari
The aim of this study was to evaluate the effect of low-level light therapy using light-emitting diodes (LEDs) on the speed of tooth movements that were required for the leveling and aligning of the lower anterior segment during non-extraction orthodontic treatment. The sample was comprised of patients (n = 40) with lower anterior crowding who were treated with self-ligating orthodontic brackets and a standardized wire sequence. A test group of patients (n = 20) who were treated with extraoral infrared light therapy for 20 min daily with at least 80 % compliance was compared to a control group (n = 20)...
October 20, 2016: Lasers in Medical Science
Balakrishnan Nirmal
Management of periungual wart is a great challenge, especially when there is subungual extension. The major cause of recurrence of wart is improper clinical assessment of its extent and not directing therapy against the entire wart. This difficulty of ascertaining its extent could be overcome with this finger-shaped red light emitting diode device. Red light in the device penetrates the thick palmar skin and dark constitutive skin colour due to its longer wavelength.
July 2016: Journal of Cutaneous and Aesthetic Surgery
Jonathan B Gillespie, Michelle Maclean, Martin J Given, Mark P Wilson, Martin D Judd, Igor V Timoshkin, Scott J MacGregor
OBJECTIVE: This study investigates possible advantages in pulsed over continuous 405-nm light-emitting diode (LED) light for bacterial inactivation and energy efficiency. BACKGROUND: Alternative nonantibiotic methods of disinfection and infection control have become of significant interest. Recent studies have demonstrated the application of systems using 405-nm LEDs for continuous disinfection of the clinical environment, and also for potential treatment of contaminated wounds...
October 19, 2016: Photomedicine and Laser Surgery
Xiaoyu Zhang, Chun Sun, Yu Zhang, Hua Wu, Changyin Ji, Yahui Chuai, Peng Wang, Shanpeng Wen, Chunfeng Zhang, William W Yu
The high photoluminescence efficiency, high color purity, and easy tunable bandgap make inorganic perovskite nanocrystals very attractive in luminescent display applications. Here, we report a color-saturated, red light-emitting diode (LED) using an inverted organic/inorganic hybrid structure and perovskite nanocrystals. We demonstrated that through a simple post treatment to the perovskite nanocrystals with polyethylenimine, the surface defects of the perovskite nanocrystals could be well passivated, leading to great enhancements on their absolute photoluminescence quantum yield and photoluminescence lifetime...
October 19, 2016: Journal of Physical Chemistry Letters
Takayo Miyakogawa, Genta Kanai, Ryoko Tatsumi, Hiroo Takahashi, Kaichiro Sawada, Takatoshi Kakuta, Masafumi Fukagawa
BACKGROUND: Feasibility of photodynamic therapy (PDT) for secondary hyperparathyroidism (SHPT) was examined in a rat model of SHPT. METHODS: A photosensitizer, 5-aminolevulinic acid (5-ALA), was injected intraperitoneally, and the parathyroid glands were irradiated either after surgical exposure with 385-nm light or transdermally with 630-nm light from a light-emitting diode (LED) lamp. RESULTS: PDT with high 5-ALA and irradiation doses caused severe hypoparathyroidism in SHPT rats within two days...
October 18, 2016: Clinical and Experimental Nephrology
Yang-Seok Yoo, Jong-Ho Na, Sung Jin Son, Yong-Hoon Cho
A critical issue in GaN-based high power light-emitting diodes (LEDs) is how to suppress the efficiency droop problem occurred at high current injection while improving overall quantum efficiency, especially in conventional c-plane InGaN/GaN quantum well (QW), without using complicated bandgap engineering or unconventional materials and structures. Although increasing thickness of each QW may decrease carrier density in QWs, formation of additional strain and defects as well as increased built-in field effect due to enlarged QW thickness are unavoidable...
October 19, 2016: Scientific Reports
Teklay Gebrecherkos, Baye Gelaw, Belay Tessema
BACKGROUND: In correctional settings tuberculosis is a public health concern. The incarcerated population is at greater risk for tuberculosis (TB) than the general population. The aim of this study was to determine the prevalence of smear positive pulmonary tuberculosis (PTB) and associated risk factors in prison settings. METHODS: A cross-sectional study was conducted among prisoners of North Gondar zone where all inmates with a history of cough for ≥ 2 weeks were included...
October 18, 2016: BMC Public Health
Michael R Hamblin
Photobiomodulation (PBM) describes the use of red or near-infrared light to stimulate, heal, regenerate, and protect tissue that has either been injured, is degenerating, or else is at risk of dying. One of the organ systems of the human body that is most necessary to life, and whose optimum functioning is most worried about by humankind in general, is the brain. The brain suffers from many different disorders that can be classified into three broad groupings: traumatic events (stroke, traumatic brain injury, and global ischemia), degenerative diseases (dementia, Alzheimer's and Parkinson's), and psychiatric disorders (depression, anxiety, post traumatic stress disorder)...
December 2016: BBA Clinical
A Krigel, M Berdugo, E Picard, R Levy-Boukris, I Jaadane, L Jonet, M Dernigoghossian, C Andrieu-Soler, A Torriglia, F Behar-Cohen
To save energy, the European directives from the Eco-design of Energy Using Products (2005/32/CE) has recommended the replacement of incandescent lamps by more economic devices such as Light Emitting Diodes (LEDs). However, the emission spectrum of these devices is enriched in blue radiations, known to be potentially dangerous to the retina. Recent studies showed that light exposure contribute to the onset of early stages of Age related macular degeneration (AMD). Here, we investigate, in albinos and pigmented rats, the effects of different exposure protocols...
October 14, 2016: Neuroscience
Yoichiro Nakano, Takashi Yanase, Taro Nagahama, Hajime Yoshida, Toshihiro Shimada
The water vapor transmission rate (WVTR) of a gas barrier coating is a critically important parameter for flexible organic device packaging, but its accurate measurement without mechanical stress to ultrathin films has been a significant challenge in instrumental analysis. At the current stage, no reliable results have been reported in the range of 10(-6) g m(-2) day(-1) that is required for organic light emitting diodes (OLEDs). In this article, we describe a solution for this difficult, but important measurement, involving enhanced sensitivity by a cold trap, stabilized temperature system, pumped sealing and calibration by a standard conductance element...
October 17, 2016: Scientific Reports
Nikolai Blanik, Konrad Heimann, Carina Pereira, Michael Paul, Vladimir Blazek, Boudewijn Venema, Thorsten Orlikowsky, Steffen Leonhardt
Vital parameter monitoring of term and preterm infants during incubator care with self-adhesive electrodes or sensors directly positioned on the skin [e.g. photoplethysmography (PPG) for oxygen saturation or electrocardiography (ECG)] is an essential part of daily routine care in neonatal intensive care units. For various reasons, this kind of monitoring contains a lot of stress for the infants. Therefore, there is a need to measure vital parameters (for instance respiration, temperature, pulse, oxygen saturation) without mechanical or conductive contact...
October 15, 2016: Biomedizinische Technik. Biomedical Engineering
Ming Dai, Xueliang Xiao, Xin Chen, Haoming Lin, Wanqing Wu, Siping Chen
With the increasing aging population as well as health concerns, chronic heart disease has become the focus of public attention. A comfortable, low-powered, and wearable electrocardiogram (ECG) system for continuously monitoring the elderly's ECG signals over several hours is important for preventing cardiovascular diseases. Traditional ECG monitoring apparatus is often inconvenient to carry, has many electrodes to attach to the chest, and has a high-power consumption. There is also a challenge to design an electrocardiograph that satisfies requirements such as comfort, confinement, and compactness...
October 14, 2016: Australasian Physical & Engineering Sciences in Medicine
Man-Keung Fung, Yan-Qing Li, Liang-Sheng Liao
A tandem organic light-emitting diode (OLED) is an organic optoelectronic device that has two or more electroluminescence (EL) units connected electrically in series with unique intermediate connectors within the device. Researchers have studied this new OLED architecture with growing interest and have found that the current efficiency of a tandem OLED containing N EL units (N > 1) should be N times that of a conventional OLED containing only a single EL unit. Therefore, this new architecture is potentially useful for constructing high-efficiency, high-luminance, and long-lifetime OLED displays and organic solid-state lighting sources...
October 13, 2016: Advanced Materials
Hongjian Li, Panpan Li, Junjie Kang, Jiianfeng Ding, Jun Ma, Yiyun Zhang, Xiaoyan Yi, Guohong Wang
We have presented broadband full-color monolithic InGaN light-emitting diodes (LEDs) by self-assembled InGaN quantum dots (QDs) using metal organic chemical vapor deposition (MOCVD). The electroluminescence spectra of the InGaN QDs LEDs are extremely broad span from 410 nm to 720 nm with a line-width of 164 nm, covering entire visible wavelength range. A color temperature of 3370 K and a color rendering index of 69.3 have been achieved. Temperature-dependent photoluminescence measurements reveal a strong carriers localization effect of the InGaN QDs layer by obvious blue-shift of emission peak from 50 K to 300 K...
October 13, 2016: Scientific Reports
Xiaofei Zhao, Baohua Zhang, Ruyan Zhao, Bing Yao, Xuejing Liu, Jun Liu, Zhiyuan Xie
Organometal halide perovskites (OHPs) are becoming a hot topic in the field of display and lighting. Unlike strategy used for solar cells, i.e. using several hundred nanometer thick OHP film for fully absorbing solar light to convert electricity, thin film OHPs (less than 50 nm) are advantageous to restrain its self-absorption drawback and thus beneficial for preparing efficient light-emitting diodes (LEDs). Here, we manipulate the excess molar ratio of MABr:PbBr2 precursors and the post annealing temperature to obtain uniform thin film OHPs and suppress the nonradiative defects...
October 13, 2016: Journal of Physical Chemistry Letters
Yang Wang, Yaoming Lu, Baoxiang Gao, Shumeng Wang, Junqiao Ding, Lixiang Wang, Xiabin Jing, Fosong Wang
A novel self-host blue-emitting iridium dendrimer, namely B-CzPO, has been designed and synthesized via a post-dendronization route, where a bipolar carbazole/triphenylphosphine oxide hybrid is selected as the peripheral dendron instead of the p-type oligocarbazole used in the unipolar analogue B-CzG2. This structural modification can render B-CzPO with more balanced charge transportation relative to B-CzG2. As a result of the significantly reduced efficiency roll-off, the nondoped phosphorescent organic light-emitting diodes (PhOLEDs) of B-CzPO show a superior high-brightness performance, revealing a luminous efficiency of 21...
October 13, 2016: ACS Applied Materials & Interfaces
Xicheng Wang, Zhengyan Zhao, Quansheng Wu, Yanyan Li, Yuhua Wang
A series of Ca2YZr2Al3O12:Eu(3+) (CYZA) phosphors were successfully synthesized through conventional solid-state method. The electronic structure and their photoluminescence or cathodoluminescence properties were investigated in detail. Under n-UV excitation, the CYZA:Eu(3+) exhibits more intense red emission than the commercial Y2O3:Eu(3+) phosphor. A WLED lamp with good color render index was obtained by fabricating the phosphor with BAM:Eu(2+) and LuAG:Ce(3+) phosphors. The phosphor also exhibits red emission with high current saturation and high resistance under low voltage electron bombardment...
October 12, 2016: Inorganic Chemistry
Patricia J Simner, Gail L Woods, Nancy L Wengenack
The immunocompromised host is at increased risk of Mycobacterium tuberculosis complex and nontuberculous mycobacteria infection. Although Mycobacterium tuberculosis complex is a significant mycobacterial pathogen, nontuberculous mycobacteria causes substantial disease in those with suppressed immune responses. Mycobacterial infections can cause significant morbidity and mortality in this patient population, and rapid identification and susceptibility testing of the mycobacterial species is paramount to patient management and outcomes...
August 2016: Microbiology Spectrum
Tong Shan, Yulong Liu, Xiangyang Tang, Qing Bai, Yu Gao, Zhao Gao, Jinyu Li, Jian Deng, Bing Yang, Ping Lu, Yuguang Ma
Great efforts have been devoted to develop efficient deep blue organic light-emitting diodes (OLEDs) materials meeting the standards of European Broadcasting Union (EBU) standard with Commission International de L'Eclairage (CIE) coordinates of (0.15, 0.06) for flat-panel displays and solid-state lightings. However, high-performanced deep blue OLEDs are still rare for applications. Herein, two efficient deep blue emitters, PIMNA and PyINA, are designed and synthesized by coupling naphthalene with phenanthreneimidazole and pyreneimidazole, respectively...
October 10, 2016: ACS Applied Materials & Interfaces
Oksana Ostroverkhova
Organic (opto)electronic materials have received considerable attention due to their applications in thin-film-transistors, light-emitting diodes, solar cells, sensors, photorefractive devices, and many others. The technological promises include low cost of these materials and the possibility of their room-temperature deposition from solution on large-area and/or flexible substrates. The article reviews the current understanding of the physical mechanisms that determine the (opto)electronic properties of high-performance organic materials...
October 10, 2016: Chemical Reviews
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"