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https://www.readbyqxmd.com/read/29775930/synthesis-photophysical-and-electrochemical-properties-of-a-blue-emitter-with-binaphthalene-and-carbazole-units
#1
Lixia Guo, Xiaoju Wang, Liheng Feng
A blue emitter, 3,3'-(2,2'-dimethoxy-[1,1'-binaphthalene]-6,6'-diyl)bis(9-benzyl-9H-carbazole), was synthesized by Suzuki coupling reaction. The photophysical properties of the emitter in solution were firstly investigated by UV-Vis absorption and fluorescence emission techniques. The results indicate that the emitter has excellent optical and electron transfer properties. The maximum absorption and emission peaks of the emitter are 302 nm and 406 nm with 67.4% fluorescence quantum yield in chloroform, respectively...
May 10, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/29775867/phytochemical-profiles-phototoxic-and-antioxidant-properties-of-eleven-hypericum-species-a-comparative-study
#2
Edoardo Napoli, Laura Siracusa, Giuseppe Ruberto, Alessandra Carrubba, Silvia Lazzara, Antonio Speciale, Francesco Cimino, Antonella Saija, Mariateresa Cristani
Hypericum is one out of the nine genera belonging to the botanical family Clusiaceae Lindl (syn. Hypericaceae Juss.; APG III, 2009). The genus contains 484 species spread worldwide, one of which, Hypericum perforatum, is largely used in folk medicine. The aim of this study was to evaluate the chemical composition, along with the antioxidant and phototoxic activity, of 11 Hypericum species grown in Sicily (H. perforatum L., H. aegypticum L., H. androsaemum L., H. calycinum L., H. hircinum L., H. hirsutum L...
May 15, 2018: Phytochemistry
https://www.readbyqxmd.com/read/29775503/artificial-rod-and-cone-photoreceptors-with-human-like-spectral-sensitivities
#3
Byeongho Park, Heehong Yang, Tai Hwan Ha, Hyun Seo Park, Seung Ja Oh, Yong-Sang Ryu, Youngho Cho, Hyo-Suk Kim, Juyeong Oh, Dong Kyu Lee, Chulki Kim, Taikjin Lee, Minah Seo, Jaebin Choi, Young Min Jhon, Deok Ha Woo, Seok Lee, Seok Hwan Kim, Hyuk-Jae Lee, Seong Chan Jun, Hyun Seok Song, Tai Hyun Park, Jae Hun Kim
Photosensitive materials contain biologically engineered elements and are constructed using delicate techniques, with special attention devoted to efficiency, stability, and biocompatibility. However, to date, no photosensitive material has been developed to replace damaged visual-systems to detect light and transmit the signal to a neuron in the human body. In the current study, artificial nanovesicle-based photosensitive materials are observed to possess the characteristics of photoreceptors similar to the human eye...
May 18, 2018: Advanced Materials
https://www.readbyqxmd.com/read/29775490/monolithic-flexible-vertical-gan-light-emitting-diodes-for-a-transparent-wireless-brain-optical-stimulator
#4
Han Eol Lee, JeHyuk Choi, Seung Hyun Lee, Minju Jeong, Jung Ho Shin, Daniel J Joe, DoHyun Kim, Chang Wan Kim, Jung Hwan Park, Jae Hee Lee, Daesoo Kim, Chan-Soo Shin, Keon Jae Lee
Flexible inorganic-based micro light-emitting diodes (µLEDs) are emerging as a significant technology for flexible displays, which is an important area for bilateral visual communication in the upcoming Internet of Things era. Conventional flexible lateral µLEDs have been investigated by several researchers, but still have significant issues of power consumption, thermal stability, lifetime, and light-extraction efficiency on plastics. Here, high-performance flexible vertical GaN light-emitting diodes (LEDs) are demonstrated by silver nanowire networks and monolithic fabrication...
May 18, 2018: Advanced Materials
https://www.readbyqxmd.com/read/29775046/solvent-assisted-surface-engineering-for-high-performance-all-inorganic-perovskite-nanocrystals-light-emitting-diodes
#5
Lin Wang, Baiquan Liu, Xin Zhao, Hilmi Volkan Demir, Haoshuang Gu, Handong Sun
All-inorganic cesium halide perovskite nanocrystals have attracted booming interests in optoelectronic applications for the sake of the readily adjustable bandgaps, high photoluminescence quantum yield, pure color emission and affordable cost. However, due to the ineluctable utilization of organic surfactants during the synthesis, the structural and optical properties of CsPbBr3 nanocrystals degrade upon transforming from colloidal solutions to solid thin films, which plagues the device operation. Here, we develop a novel solvent-assisted surface engineering strategy, producing high quality CsPbBr3 thin films for device applications...
May 18, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29774610/high-performance-fluorescent-organic-light-emitting-diodes-utilizing-an-asymmetric-anthracene-derivative-as-an-electron-transporting-material
#6
Dongdong Zhang, Xiaozeng Song, Haoyuan Li, Minghan Cai, Zhengyang Bin, Tianyu Huang, Lian Duan
Fluorescent organic light-emitting diodes with thermally activated delayed fluorescent sensitizers (TSF-OLEDs) have aroused wide attention, the power efficiencies of which, however, are limited by the mutual exclusion of high electron-transport mobility and large triplet energy of electron-transporting materials (ETMs). Here, an asymmetric anthracene derivative with electronic properties manipulated by different side groups is developed as an ETM to promote TSF-OLED performances. Multiple intermolecular interactions are observed, leading to a kind of "cable-like packing" in the crystal and favoring the simultaneous realization of high electron-transporting mobility and good exciton-confinement ability, albeit the low triplet energy of the ETM...
May 17, 2018: Advanced Materials
https://www.readbyqxmd.com/read/29772921/a-multicomponent-intervention-to-encourage-stair-use-in-municipal-buildings
#7
Brent W Moloughney, Gayle E Bursey, Rebecca B Fortin, Maria G Morais, Khanh Thi Dang
PURPOSE: Evaluate the incremental impact of environmental stairwell enhancements on stair usage in addition to prompts. DESIGN: Phased, nonrandomized, quasi-experimental intervention. SETTING: Two 6-story and one 8-story municipal government office buildings-each with 2 stairwells. PARTICIPANTS: Approximately 2800 municipal employees and 1000 daily visitors. INTERVENTION: All stairwells received door wraps and point-of-decision and wayfinding prompts...
January 1, 2018: American Journal of Health Promotion: AJHP
https://www.readbyqxmd.com/read/29772832/characterization-of-luminescent-materials-with-151-eu-m%C3%A3-ssbauer-spectroscopy
#8
REVIEW
Franziska Steudel, Jacqueline A Johnson, Charles E Johnson, Stefan Schweizer
The application of Mössbauer spectroscopy to luminescent materials is described. Many solids doped with europium are luminescent, i.e., when irradiated with light they emit light of a longer wavelength. These materials therefore have practical applications in tuning the light output of devices like light emitting diodes. The optical properties are very different for the two possible valence states Eu 2 + and Eu 3 + , the former producing ultraviolet/visible light that shifts from violet to red depending on the host and the latter red light, so it is important to have a knowledge of their behavior in a sample environment...
May 17, 2018: Materials
https://www.readbyqxmd.com/read/29772830/determination-of-the-maximum-temperature-in-a-non-uniform-hot-zone-by-line-of-site-absorption-spectroscopy-with-a-single-diode-laser
#9
Vladimir V Liger, Vladimir R Mironenko, Yurii A Kuritsyn, Mikhail A Bolshov
A new algorithm for the estimation of the maximum temperature in a non-uniform hot zone by a sensor based on absorption spectrometry with a diode laser is developed. The algorithm is based on the fitting of the absorption spectrum with a test molecule in a non-uniform zone by linear combination of two single temperature spectra simulated using spectroscopic databases. The proposed algorithm allows one to better estimate the maximum temperature of a non-uniform zone and can be useful if only the maximum temperature rather than a precise temperature profile is of primary interest...
May 17, 2018: Sensors
https://www.readbyqxmd.com/read/29772726/an-alternative-lifetime-model-for-white-light-emitting-diodes-under-thermal%C3%A2-electrical-stresses
#10
Xi Yang, Bo Sun, Zili Wang, Cheng Qian, Yi Ren, Dezhen Yang, Qiang Feng
The lifetime prediction using accelerated degradation test (ADT) method has become a main issue for white light emitting diodes applications. This paper proposes a novel lifetime model for light emitting diodes (LEDs) under thermal and electrical stresses, where the junction temperature and driving current are deemed the input parameters for lifetime prediction. The features of LEDs' lifetime and the law of lumen depreciation under dual stresses are combined to build the lifetime model. The adoption of thermal and electrical stresses overcomes the limitation of single stress, and junction temperature in accelerated degradation test as thermal stress is more reliable than ambient temperature in conventional ADT...
May 16, 2018: Materials
https://www.readbyqxmd.com/read/29772513/a-transition-to-white-led-increases-ecological-impacts-of-nocturnal-illumination-on-aquatic-primary-producers-in-a-lowland-agricultural-drainage-ditch
#11
Maja Grubisic, Roy H A van Grunsven, Alessandro Manfrin, Michael T Monaghan, Franz Hölker
The increasing use of artificial light at night (ALAN) has led to exposure of freshwater ecosystems to light pollution worldwide. Simultaneously, the spectral composition of nocturnal illumination is changing, following the current shift in outdoor lighting technologies from traditional light sources to light emitting diodes (LED). LEDs emit broad-spectrum white light, with a significant amount of photosynthetically active radiation, and typically a high content of blue light that regulates circadian rhythms in many organisms...
May 14, 2018: Environmental Pollution
https://www.readbyqxmd.com/read/29772456/new-insights-into-the-in-vitro-biological-effects-in-silico-docking-and-chemical-profile-of-clary-sage-salvia-sclarea-l
#12
Gokhan Zengin, Ismail Senkardes, Adriano Mollica, Carene Marie Nancy Picot-Allain, Gizem Bulut, Ahmet Dogan, M Fawzi Mahomoodally
Salvia sclarea L. is traditionally used to manage common human ailments and is consumed as a food product. This study aimed to establish the phytochemical profile and antioxidant potential of ethyl acetate, methanol, and water extracts of Salvia sclarea. The inhibitory action of the extracts against α-amylase, α-glucosidase, acetylcholinesterase, butyrylcholinesterase, and tyrosinase was also investigated. Methanol extract showed the highest phenolic and flavonoid contents (81.78 mg GAE/g extract and 40...
May 6, 2018: Computational Biology and Chemistry
https://www.readbyqxmd.com/read/29772183/accurate-treatment-of-charge-transfer-excitations-and-thermally-activated-delayed-fluorescence-using-the-particle-particle-random-phase-approximation
#13
Rachael Al-Saadon, Christopher Sutton, Weitao Yang
Thermally activated delayed florescence (TADF) is a mechanism that increases the electroluminescence efficiency in organic light-emitting diodes by harnessing both singlet and triplet excitons. TADF is facilitated by a small energy difference between the first singlet (S1 ) and triplet (T1 ) excited states (ΔE(ST)), which is minimized by spatial separation of the donor and acceptor moieties. The resultant charge-transfer (CT) excited states are difficult to model using time-dependent density functional theory (TDDFT) because of the delocalization error present in standard density functional approximations to the exchange-correlation energy...
May 17, 2018: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/29772045/ocular-tolerance-of-contemporary-electronic-display-devices
#14
Andrew J Clark, Paul Yang, Khizer R Khaderi, Andrew A Moshfeghi
Electronic displays have become an integral part of life in the developed world since the revolution of mobile computing a decade ago. With the release of multiple consumer-grade virtual reality (VR) and augmented reality (AR) products in the past 2 years utilizing head-mounted displays (HMDs), as well as the development of low-cost, smartphone-based HMDs, the ability to intimately interact with electronic screens is greater than ever. VR/AR HMDs also place the display at much closer ocular proximity than traditional electronic devices while also isolating the user from the ambient environment to create a "closed" system between the user's eyes and the display...
May 1, 2018: Ophthalmic Surgery, Lasers & Imaging Retina
https://www.readbyqxmd.com/read/29771774/bronchoscopic-laser-interstitial-thermal-therapy-an-experimental-study-in-normal-porcine-lung-parenchyma
#15
Roberto F Casal, Garrett Walsh, Mark McArthur, Lori R Hill, Maria F Landaeta, Aristides J Armas Villalba, Philip Ong, Labib Debiane, Erik Vakil, Horiana B Grosu, Carlos A Jimenez, David Ost, Roberto Adachi, George A Eapen
BACKGROUND: Population aging and lung cancer screening strategies may lead to an increase in detection of early-stage lung cancer in medical inoperable patients. Recent advances in peripheral bronchoscopy have made it a suitable platform for ablation of small peripheral tumors. METHODS: We investigated the tissue-ablative effect of a diode laser bronchoscopically applied by a laser delivery fiber (LDF) with wide aperture on porcine lung parenchyma. Laser was tested ex vivo and in vivo to identify the most effective power settings and LDF...
May 16, 2018: Journal of Bronchology & Interventional Pulmonology
https://www.readbyqxmd.com/read/29771533/half-cell-ion-concentration-polarization-on-nafion-coated-electrode
#16
Rhokyun Kwak, Jongyoon Han
On ion selective membranes, cation/anion selective transport under electric field initiates ion concentration polarization (ICP); ion concentration increases at one side of the membrane (ion enrichment), while it decreases at the other side (ion depletion). This polarization always occurs as the pair of ion enrichment and ion depletion. Here, departing from such pair generation, we demonstrate that only half of ICP (either ion enrichment or ion depletion) can be solitary on a Nafion-coated electrode. Current-voltage-time responses and conductance measurement capture this half-cell ICP with qualitative in situ pH / ion concentration visualization...
May 17, 2018: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/29771239/iii-v-heterostructure-tunnel-field-effect-transistor
#17
Clarissa Convertino, Cezar Zota, Heinz Schmid, Adrian M Ionescu, Kirsten Moselund
The Tunnel Field-Effect Transistor (TFET) is regarded as one of the most promising solid-state switches to overcome the power dissipation challenge in ultra-low power integrated circuits. TFETs take advantage of quantum mechanical tunneling hence exploit a different current control mechanism compared to standard MOSFETs. In this review, we describe state-of-the-art development of TFET both in terms of performances and of materials integration and we identify the main remaining technological challenges such as heterojunction defects and oxide/channel interface traps causing trap-assisted-tunneling (TAT)...
May 17, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/29770982/characterisation-of-phenolic-compounds-by-uplc-qtof-ms-ms-of-geopropolis-from-the-stingless-bee-melipona-subnitida-janda%C3%A3-ra
#18
Silvana Alves de Souza, Telma Maria Guedes da Silva, Eva Monica Sarmento da Silva, Celso Amorim Camara, Tania Maria Sarmento Silva
INTRODUCTION: Melipona subnitida Ducke (jandaíra) is a stingless bee native to north-eastern Brazil, which produces geopropolis, a mixture of beeswax, plant resins, pollens and earth that is used for sealing beehives. OBJECTIVE: To extend the knowledge on phenolic compounds in fractions obtained by C18-solid phase extraction (SPE) of nine geopropolis samples from Melipona subnitida collected at different times. METHODOLOGY: Chromatographic profiles of nine samples of geopropolis from jandaíra were analysed by ultra-performance liquid chromatography coupled with a diode array detector and quadrupole time-of-flight mass spectrometry (UPLC-DAD-QTOF-MS/MS) and combined with the use of data-independent acquisition (MSE) for the profiling and structural characterisation of the phenolic compounds...
May 17, 2018: Phytochemical Analysis: PCA
https://www.readbyqxmd.com/read/29770685/tft-directed-electroplating-of-rgb-luminescent-films-without-a-vacuum-or-mask-toward-a-full-color-amoled-pixel-matrix
#19
Rong Wang, Donglian Zhang, You Xiong, Xuehong Zhou, Cao Liu, Weifeng Chen, Weijing Wu, Lei Zhou, Miao Xu, Lei Wang, Linlin Liu, Junbiao Peng, Yuguang Ma, Yong Cao
The thin-film transistor (TFT) driving circuit is a separate electronic component embedded within the panel itself to switch the current for each pixel in active-matrix organic light-emitting diode displays. We reported a TFT-directed dye electroplating method to fabricate pixels; this would be a new method to deposit films on prepatterned electrode for organic full-color display, where TFT driving circuit provide a switching current signal to drive and direct dye depositing on selected RGB pixels. A prototype patterned color pixel matrix was achieved, as high-quality light-emitting films with uniform morphology, pure RGB chromaticity, and stable output...
May 18, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29769771/evaluation-of-diode-laser-and-stannous-fluoride-in-the-treatment-of-root-sensitivity-after-access-flap-surgery-randomized-controlled-clinical-trial
#20
Chetan Purushottam Raut, Kunal Sunder Sethi, Bhagyashree Kohale, Alefiya Mamajiwala, Ayushya Warang
Background: Postsurgical root sensitivity has always been an enigma to the periodontists. There is a plethora of evidence suggesting the presence of root sensitivity following periodontal flap surgical procedures. Thus, the aim of the present study was to compare and evaluate the effect of low-power diode lasers with and without topical application of stannous fluoride (SnF2 ) gel in the treatment of root sensitivity and also evaluate whether laser creates any placebo effect in the control group or not...
March 2018: Journal of Indian Society of Periodontology
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