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https://www.readbyqxmd.com/read/28933533/luminescence-tuning-thermal-quenching-and-electronic-structure-of-narrow-band-red-emitting-nitride-phosphors
#1
Dianpeng Cui, Zhen Song, Zhiguo Xia, Quanlin Liu
Exploring high-performance narrow-band red-emitting phosphor is an important challenge for improving white light LEDs. Here, on the basis of three interesting nitride phosphors with similar vierer rings framework structure, two phosphor series, Eu(2+)-doped Sr(LiAl)1-xMg2xAl2N4 and Sr(LiAl3)1-y(Mg3Si)yN4 (x, y = 0-1), are successfully synthesized by a solid state reaction. They show narrow-band red emission with tunable emission peaks from 614 to 658 nm and 607 to 663 nm. The varying luminescence behaviors with composition and structure are discussed based on centroid shift, crystal field splitting and Stokes shift...
September 21, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28932727/effectiveness-of-cholangioscopy-using-narrow-band-imaging-for-hepatobiliary-malignancies
#2
Ji Woong Jang, Dong Hyo Noh, Kyu-Hyun Paik, Sae Hee Kim, Il-Hyun Paik, Sung Hee Jung
PURPOSE: Recently, cholangioscopy using narrow band imaging (NBI) has been used as a diagnostic modality for better visualization in hepatobiliary malignancies; however, there are few reports on it. Our aim is to evaluate the effectiveness of cholangioscopy using NBI in hepatobiliary malignancies. METHODS: Between January 2007 and December 2016, 152 cholangioscopies using percutaneous approach were conducted in total 123 patients. Among these, 36 patients were suspicious of hepatobiliary malignancies...
September 2017: Annals of Surgical Treatment and Research
https://www.readbyqxmd.com/read/28932570/the-technique-of-endoscopic-airway-tumor-treatment
#3
REVIEW
Simone Scarlata, Lello Fuso, Gabriele Lucantoni, Francesco Varone, Daniele Magnini, Raffaele Antonelli Incalzi, Gianni Galluccio
More than half of primary lung cancers are not resectable at diagnosis and 40% of deaths may be secondary to loco-regional disease. Many of these patients suffer from symptoms related to airways obstruction. Indications for therapeutic endoscopic treatment are palliation of dyspnea and other obstructive symptoms in advanced cancerous lesions and cure of early lung cancer. Bronchoscopic management is also indicated for all those patients suffering from benign or minimally invasive neoplasm who are not suitable for surgery due to their clinical conditions...
August 2017: Journal of Thoracic Disease
https://www.readbyqxmd.com/read/28930350/vertical-dielectric-screening-of-few-layer-van-der-waals-semiconductors
#4
Jahyun Koo, Shiyuan Gao, Hoonkyung Lee, Li Yang
Vertical dielectric screening is a fundamental parameter of few-layer van der Waals two-dimensional (2D) semiconductors. However, unlike the widely-accepted wisdom claiming that the vertical dielectric screening is sensitive to the thickness, our first-principles calculation based on the linear response theory (within the weak field limit) reveals that this screening is independent of the thickness and, in fact, it is the same as the corresponding bulk value. This conclusion is verified in a wide range of 2D paraelectric semiconductors, covering narrow-gap ones and wide-gap ones with different crystal symmetries, providing an efficient and reliable way to calculate and predict static dielectric screening of reduced-dimensional materials...
September 20, 2017: Nanoscale
https://www.readbyqxmd.com/read/28926248/short-wave-near-infrared-linear-dichroism-of-two-dimensional-germanium-selenide
#5
Xiaoting Wang, Yongtao Li, Le Huang, Xiang-Wei Jiang, Lang Jiang, Huanli Dong, Zhongming Wei, Jingbo Li, Wenping Hu
Polarized detection has been brought into operation for optics applications in visible band. Although an advanced requirement in short-wave near-infrared (SW-NIR) (700-1100 nm) is proposed, the approaching of this target remains under way. Theoretically, IV-VI chalcogenides two-dimensional (2D) structures, e.g., 2D germanium selenide (GeSe), possess anisotropic layered orthorhombic structure, narrow 1.1-1.2eV bandgap and potentially meet the demand. Here we report the unusual angle dependences of Raman spectra on controllably synthesized high-quality 2D GeSe crystals...
September 19, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28926231/resonance-emission-enhancement-ree-for-narrow-band-red-emitting-a2gef6-mn-4-a-na-k-rb-cs-phosphors-synthesized-via-a-precipitation-cation-exchange-route
#6
Hongzhou Lian, Qingming Huang, Yeqing Chen, Kai Li, Sisi Liang, Mengmeng Shang, Manman Liu, Jun Lin
Narrow band red-emitting A2GeF6:Mn(4+) (A = Na, K, Rb, Cs) phosphors were prepared through a two-step precipitation-cation exchange route using a K2MnF6 precursor as the Mn(4+) source. The phase purity, morphology, and constituent were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectric spectroscopy (XPS), and electron paramagnetic resonance (EPR) examination. Optical properties were investigated by photoluminescence spectra (PL and PLE) and high-resolution PL. A temperature-dependent PL examination was performed to investigate the electron-phonon coupling emission mechanism of Mn(4+) in these alkali fluorogermanates...
September 19, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28926037/strain-induced-ferroelectricity-and-lattice-coupling-in-basno3-and-srsno3
#7
Yajun Zhang, Jie Wang, M P K Sahoo, Takahiro Shimada, Takayuki Kitamura
Perovskite stannates such as BaSnO3 and SrSnO3 exhibit promising photovoltaic properties, and hold promise for application in solar cell devices. However, the lack of ferroelectricity and the wide band gap in these materials limit their potential for photovoltaic applications. Here, by first-principles calculations, we demonstrate the realization of a primary ferroelectric polarization in non-ferroelectric BaSnO3 and SrSnO3 through strain engineering. In addition to the appearance of polarization, the band gaps of the materials are greatly narrowed when the paraelectric to ferroelectric phase transition takes place under compressive strain...
September 19, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28924585/evaluation-of-image-enhanced-endoscopic-technology-using-advanced-diagnostic-endoscopy-for-the-detection-of-early-gastric-cancer-a-pilot-study
#8
Daisuke Yamaguchi, Shinya Kodashima, Mitsuhiro Fujishiro, Satoshi Ono, Keiko Niimi, Satoshi Mochizuki, Yosuke Tsuji, Itsuko Asada-Hirayama, Yoshiki Sakaguchi, Satoki Shichijo, Chihiro Minatsuki, Nobutake Yamamichi, Kazuhiko Koike
BACKGROUND AND STUDY AIMS : Image-enhanced endoscopy (IEE) plays an important role in early detection and detailed examination of early gastric cancer (EGC). The current study aimed to clarify the efficacy of IEE using advanced diagnostic endoscopy for EGC detection without magnification. PATIENTS AND METHODS : We performed endoscopic examinations without magnification in patients referred to our hospital with a diagnosis of upper gastrointestinal tumor detected through routine screening endoscopy...
September 2017: Endoscopy International Open
https://www.readbyqxmd.com/read/28922485/novel-3d-semiconducting-open-frameworks-based-on-cuprous-bromides-with-visible-light-driven-photocatalytic-properties
#9
Xiao-Wu Lei, Cheng-Yang Yue, Jun-Chao Wei, Rui-Qing Li, Fu-Qi Mi, Yan Li, Lu Gao, Quan-Xiu Liu
Visible light driven photocatalysts based on crystalline microporous metal halogenides received much less attention compared with dense or composite oxide semiconductors. Using the well-known photosensitive transition metal-complexes [TM(2,2-bipy)3 ](2+) (TM=Fe, Co, Ni, Ru) as templates, a special three-dimensional (3D) metal halogenide framework of [TM(2,2-bipy)3 ]Cu4 Br6 was designed with [Cu4 Br4 ] cluster as 4-connected node. These microporous materials feature narrow band gaps and stable visible light driven photocatalytic properties including water reduction to provide H2 and photodegradation of organic pollutants...
August 9, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28920017/esophageal-atresia-with-tracheo-esophageal-fistula-presenting-beyond-7-days
#10
Nilesh Nagdeve, Mohini Sukhdeve, Tushar Thakre, Suresh Morey
AIM: To describe our experience of neonates with esophageal atresia with tracheo-esophageal fistula (EA with TEF) who presented after a week. DESIGN: Retrospective study of the patients of EA with TEF who presented after a week. STUDY SETTING: Department of Pediatric Surgery, Government Medical College Nagpur. Study Duration: Eight years. MATERIALS AND METHODS: Demographic information, hematological, biochemical and radiological data were obtained from the patients' medical records...
July 2017: Journal of Neonatal Surgery
https://www.readbyqxmd.com/read/28919935/hybridization-of-single-nanocrystals-of-cs4pbbr6-and-cspbbr3
#11
Chris de Weerd, Junhao Lin, Leyre Gomez, Yasufumi Fujiwara, Kazutomo Suenaga, Tom Gregorkiewicz
Nanocrystals of all-inorganic cesium lead halide perovskites (CsPbX3, X = Cl, Br, I) feature high absorption and efficient narrow-band emission which renders them promising for future generation of photovoltaic and optoelectronic devices. Colloidal ensembles of these nanocrystals can be conveniently prepared by chemical synthesis. However, in the case of CsPbBr3, its synthesis can also yield nanocrystals of Cs4PbBr6 and the properties of the two are easily confused. Here, we investigate in detail the optical characteristics of simultaneously synthesized green-emitting CsPbBr3 and insulating Cs4PbBr6 nanocrystals...
September 7, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
https://www.readbyqxmd.com/read/28917347/optical-diagnosis-of-early-colorectal-cancer-riding-the-highs%C3%A2-and-lows-of-the-japanese-narrow-band-imaging-expert%C3%A2-team-classification
#12
EDITORIAL
Sarah K McGill, Roy Soetikno, Tonya Kaltenbach
No abstract text is available yet for this article.
October 2017: Gastrointestinal Endoscopy
https://www.readbyqxmd.com/read/28915734/ce-in-the-4-oxidation-state-anion-photoelectron-spectroscopy-and-photodissociation-of-small-cexoyhz-molecules
#13
Josey E Topolski, Jared O Kafader, Caroline Chick Jarrold
The anion photoelectron (PE) spectra of a range of small mono-cerium molecular species, along with the Ce2O4(-) and Ce3O6(-) stoichiometric clusters, are presented and analyzed with the support of density functional theory calculations. A common attribute of all of the neutral species is that the Ce centers in both the molecules and clusters are in the +4 oxidation state. In bulk ceria (CeO2), an unoccupied, narrow 4f band lies between the conventional valence (predominantly O 2p) and conduction (Ce 5d) bands...
September 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28915504/in-situ-optical-properties-of-foliar-flavonoids-implication-for-non-destructive-estimation-of-flavonoid-content
#14
Anatoly Gitelson, Olga Chivkunova, Tatiana Zhigalova, Alexei Solovchenko
Flavonoids are a ubiquitous multifunctional group of phenolics of paramount importance for the terrestrial plants involved in protection from biotic and abiotic stresses, color and chemical signaling and other functions. Deciphering of in situ absorption of foliar Flv is important but was thought to be impossible due to a strong overlap with other pigments, complex in situ chemistry of Flv and sophisticated leaf optics. We deduced in situ absorbance of foliar Flv and introduced a concept of specific absorbance spectrum indicative of each pigment group contribution to light absorption and provided a rationale for the choice of spectral bands for non-destructive assessment of Flv in leaves with variable content of other pigments including anthocyanins...
September 1, 2017: Journal of Plant Physiology
https://www.readbyqxmd.com/read/28915011/highly-controllable-and-efficient-synthesis-of-mixed-halide-cspbx3-x-cl-br-i-perovskite-qds-toward-the-tunability-of-entire-visible-light
#15
Ying Su, Xuejiao Chen, Wenyu Ji, Qinghui Zeng, Zhongyuan Ren, Zisheng Su, Lei Liu
CsPbX3 (X = Cl, Br, I) perovskite quantum dots (PQDs) have been intensively investigated on photoelectric devices due to their superior optical properties. To date, the stability of CsPbX3 PQDs is still an open challenge. The previous mixed-halide CsPbX3 PQDs were generally obtained via the anion-exchange method at 40 °C. Here, the single- and mixed-halide CsPbX3 PQDs are synthesized at high temperature via the hot injection technique. The surface ligands could thus be strongly coordinated onto the surface of the PQDs, which dramatically improve the optical properties of the PQDs...
September 15, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28914610/fluorescent-j-aggregates-of-cyanine-dyes-basic-research-and-applications-review
#16
Julia L Bricks, Yuri L Slominsky, Ihor Panas, Aleksander Demchenko
J-aggregates are fascinating fluorescent nanomaterials formed by highly ordered assembly of organic dyes with the spectroscopic properties dramatically different from that of single or disorderly assembled dye molecules. They demonstrate very narrow red-shifted absorption and emission bands, strongly increased absorbance together with the decrease of radiative lifetime, highly polarized emission and other valuable features. The mechanisms of their electronic transitions are understood by formation of delocalized excitons already on the level of several coupled monomers...
September 15, 2017: Methods and Applications in Fluorescence
https://www.readbyqxmd.com/read/28906522/correlation-between-electronic-structure-transport-and-electrochemical-properties-of-a-lini1-y-zcoymnzo2-cathode-material
#17
Janina Molenda, Anna Milewska, Wojciech Zając, Michal Rybski, Janusz Tobola
Herein, the correlation between electronic structure, transport and electrochemical properties of layered LixNi1-y-zCoyMnzO2 cathode material is revealed. Comprehensive experimental studies of physicochemical properties of LixNi1-y-zCoyMnzO2 cathode material (XRD, electrical conductivity, thermoelectric power) are supported by electronic structure calculations performed using the Korringa-Kohn-Rostoker method with the coherent potential approximation (KKR-CPA) to account for the chemical disorder. It is found that even small O defects (∼1%) could significantly modify electronic density of states DOS characteristics via the formation of extra broad peaks inside the former band gap leading to its substantial narrowing...
September 14, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28906087/phototherapy-for-vitiligo-what-s-new
#18
Andrea Paro Vidolin, Caterina Aurizi, Giovanni Leone
Vitiligo is a disorder characterized by the development of depigmented macules and patches. Existing treatments include topical and systemic immunosuppressants, topical vitamin D analogues in monotherapy or in association with phototherapy, phototherapy and surgical techniques, which together may serve to halt disease progression, stabilize depigmented lesions, and encourage repigmentation. Narrow-band UVB (NB-UVB 310-315 nm) radiation is now considered as the "gold standard" for the treatment of diffuse vitiligo...
October 2017: Giornale Italiano di Dermatologia e Venereologia: Organo Ufficiale, Società Italiana di Dermatologia e Sifilografia
https://www.readbyqxmd.com/read/28900169/negative-differential-conductance-hot-carrier-avalanching-in-monolayer-ws2-fets
#19
G He, J Nathawat, C-P Kwan, H Ramamoorthy, R Somphonsane, M Zhao, K Ghosh, U Singisetti, N Perea-López, C Zhou, A L Elías, M Terrones, Y Gong, X Zhang, R Vajtai, P M Ajayan, D K Ferry, J P Bird
The high field phenomena of inter-valley transfer and avalanching breakdown have long been exploited in devices based on conventional semiconductors. In this Article, we demonstrate the manifestation of these effects in atomically-thin WS2 field-effect transistors. The negative differential conductance exhibits all of the features familiar from discussions of this phenomenon in bulk semiconductors, including hysteresis in the transistor characteristics and increased noise that is indicative of travelling high-field domains...
September 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28898731/ferroelectric-spontaneous-polarization-steering-charge-carriers-migration-for-promoting-photocatalysis-and-molecular-oxygen-activation
#20
Hongwei Huang, Shuchen Tu, Xin Du, Yihe Zhang
Introducing a polarization electric field in photocatalyst system is regarded asa new concept for photocatalytic activity enhancement. In this work, we first unearth that the spontaneous polarization of ferroelectric BaTiO3 promotes the photocatalytic and molecular oxygen activation performance of the narrow-band-gap semiconductor BiOI. Ferroelectric tetragonal-phase BaTiO3 (T-BaTiO3) were prepared via calcination of nonferroelectric cubic-phase BaTiO3 (C-BaTiO3), and their polarization ability was verified via ultrasonication-assisted piezoelectric catalytic degradation...
September 6, 2017: Journal of Colloid and Interface Science
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