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https://www.readbyqxmd.com/read/28429503/cleavage-of-a-p-p-double-bond-mediated-by-n-heterocyclic-carbenes
#1
Naoki Hayakawa, Kazuya Sadamori, Shota Tsujimoto, Miho Hatanaka, Tomonari Wakabayashi, Tsukasa Matsuo
The reaction of the bulky diphosphenes (Rind)P=P(Rind) (1; Rind=1,1,3,3,5,5,7,7-octa-R-substituted s-hydrindacen-4-yl) with two molecules of N-heterocyclic carbene (NHC; 1,3,4,5-tetramethylimidazol-2-ylidene) resulted in the quantitative formation of the NHC-bound phosphinidenes NHC→P(Rind) (2), along with the cleavage of the P=P double bond. The reaction times are dependent on the steric size of the Rind groups (11 days for 2 a (R=Et) and 2 h for 2 b (R=Et, Me) at room temperature). The mechanism for the double bond-breaking is proposed to proceed via the formation of the NHC-coordinated, highly polarized diphospehenes 3 as an intermediate...
April 21, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28429273/assessment-of-the-temporal-and-spatial-distribution-of-atmospheric-pcns-and-their-air-soil-exchange-using-passive-air-samplers-in-shanghai-east-china
#2
Qingqi Die, Zhiqiang Nie, Bo Yue, Xuemei Zhu, Xingbao Gao, Jianyuan Wang, Yufei Yang, Yanyan Fang, Qifei Huang
A total of 47 passive air samples and 25 soil samples were collected to study the temporal trend, distribution, and air-soil exchange of polychlorinated naphthalenes (PCNs) in Shanghai, China. Atmospheric PCNs ranged from 3.44 to 44.1 pg/m(3) (average of 21.9 pg/m(3)) in summer and 13.6 to 153 pg/m(3) (average of 40.0 pg/m(3)) in winter. In the soil samples, PCN concentrations were 54.7-1382 pg/g dry weight (average of 319 pg/g). Tri-CNs and tetra-CNs were two dominant homolog groups in air samples, while di-CNs were also found at comparable proportions to tri-CNs and tetra-CNs in soil samples...
April 21, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28429123/optical-coherence-tomography-angiography-vessel-density-mapping-at-various-retinal-layers-in-healthy-and-normal-tension-glaucoma-eyes
#3
Joong Won Shin, Kyung Rim Sung, Ji Yun Lee, Junki Kwon, Mincheol Seong
PURPOSE: To investigate peripapillary vessel density at various spatial locations and layers in healthy and normal tension glaucoma eyes using optical coherence tomography angiography (OCTA). METHODS: A commercial OCTA device (AngioPlex; Carl Zeiss Meditec) was used to image microvasculature in a 6 × 6-mm optic disc region. Vessel densities of superficial and deep retinal layers were calculated using an automatic thresholding algorithm. Vessel density maps were plotted by averaging individual angiogram images...
April 20, 2017: Graefe's Archive for Clinical and Experimental Ophthalmology
https://www.readbyqxmd.com/read/28425286/enantioselective-spirocyclopropanation-of-para-quinone-methides-using-ammonium-ylides
#4
Lukas Roiser, Mario Waser
The use of Cinchona alkaloid-based chiral ammonium ylides allows for the first highly enantioselective and broadly applicable spirocyclopropanation reactions of para-quinone methides. This strategy provides a straightforward protocol toward the chiral spiro[2.5]octa-4,7-dien-6-one skeleton, which is a frequently found structural motif in important biologically active molecules.
April 20, 2017: Organic Letters
https://www.readbyqxmd.com/read/28421739/an-ultra-efficient-cap-exchange-protocol-to-compact-biofunctional-quantum-dots-for-sensitive-ratiometric-biosensing-and-cell-imaging
#5
Weili Wang, Yuan Guo, Christian Tiede, Siyuan Chen, Michal Kopytynski, Yifei Kong, Alexander N Kulak, Darren Tomlinson, Rongjun Chen, Michael John McPherson, Dejian Zhou
An ultra-efficient cap-exchange protocol (UCEP) that can convert hydrophobic quantum dots (QDs) into stable, biocompatible and aggregation-free water-dispersed ones at a ligand:QD molar ratio (LQMR) as low as 500, some 20-200 fold less than most literature methods has been developed. The UCEP works conveniently with air-stable lipoic acid (LA)-based ligands by exploiting tris(2-carboxylethyl phosphine) based rapid in situ reduction. The resulting QDs are compact (hydrodynamic radius, Rh, <4.5 nm), bright (retaining >90% of original fluorescence), resist nonspecific adsorption of proteins and display good stability in biological buffers even with high salt content (e...
April 19, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28421632/rigidly-tethered-bis-phosphoric-acids-generation-of-tunable-chiral-fluorescent-frameworks-and-unexpected-selectivity-for-the-detection-of-ferric-ions
#6
Frescilia Octa-Smolin, Raja Mitra, Maike Thiele, Constantin-Gabriel Daniliuc, Linda Stegemann, Cristian Strassert, Jochen Niemeyer
We describe the straightforward synthesis of a series of bis-phosphoric acids (R,R)-1a/b/c/d, featuring two chiral 1,1´-binaphthyl-phosphoric acid units which are tethered by rigid, π-conjugated linkers. The nature of the linker has a profound influence on the properties of the bis-phosphoric acids, such as their self-association behavior and their interaction with metal ions. This led to the identification of one preferred bis-phosphoric acid (R,R)-1d, which shows selective fluorescence quenching in the presence of ferric ions (Fe3+)...
April 18, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28419405/optical-coherence-tomography-angiography-features-in-melanocytoma-of-the-optic-nerve
#7
Adriano Carnevali, Lea Querques, Ilaria Zucchiatti, Vincenzo Scorcia, Francesco Bandello, Giuseppe Querques
Optic disc melanocytoma (ODM) is a pigmented tumor with malignant potential characterized clinically as a dark brown to black lesion with feathery margins. The authors report a case of ODM and describe the utility of optical coherence tomography angiography (OCTA) in detecting superficial tumor vascularization. This case report demonstrated the ability of OCTA to reveal the fine abnormal retinal vasculature on the surface of the lesion, a characteristic of ODM, which has been previously correlated with tumor growth...
April 1, 2017: Ophthalmic Surgery, Lasers & Imaging Retina
https://www.readbyqxmd.com/read/28419395/choriocapillaris-changes-imaged-by-oct-angiography-after-half-dose-photodynamic-therapy-for-chronic-central-serous-chorioretinopathy
#8
Kyoko Fujita, Akiyuki Kawamura, Mitsuko Yuzawa
BACKGROUND AND OBJECTIVE: To evaluate the choriocapillaris using optical coherence tomographic angiography (OCTA) after half-dose verteporfin photodynamic therapy (hd-PDT) for chronic central serous chorioretinopathy (CSC). PATIENTS AND METHODS: We studied six eyes (six patients) with chronic CSC treated by hd-PDT. OCTA was performed before, 1 week after, and 1 month after hd-PDT. The area of flow abnormality at the choriocapillaris level within the PDT spot after hd-PDT was compared with that before hd-PDT...
April 1, 2017: Ophthalmic Surgery, Lasers & Imaging Retina
https://www.readbyqxmd.com/read/28406171/optical-coherence-tomography-angiography-to-estimate-retinal-blood-flow-in-eyes-with-retinitis-pigmentosa
#9
Masako Sugahara, Manabu Miyata, Kenji Ishihara, Norimoto Gotoh, Satoshi Morooka, Ken Ogino, Tomoko Hasegawa, Takako Hirashima, Munemitsu Yoshikawa, Masayuki Hata, Yuki Muraoka, Sotaro Ooto, Kenji Yamashiro, Nagahisa Yoshimura
Ophthalmologists sometimes face difficulties in identifying the origin of visual acuity (VA) loss in a retinitis pigmentosa (RP) patient, particularly before cataract surgery: cataract or the retinal disease state. Therefore, it is important to identify the significant factors correlating with VA. Nowadays, retinal blood flow in superficial and deep layers can be estimated non-invasively using optical coherence tomography angiography (OCTA). We estimated blood flow per retinal layer by using OCTA; investigated the correlation between VA and other parameters including blood flow and retinal thickness; and identified the most associated factor with VA in patients with RP...
April 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28403072/retinal-microvascular-alterations-related-to-diabetes-assessed-by-optical-coherence-tomography-angiography-a-cross-sectional-analysis
#10
Julien Gozlan, Pierre Ingrand, Olivier Lichtwitz, Agathe Cazet-Supervielle, Léa Benoudis, Michele Boissonnot, Samy Hadjadj, Nicolas Leveziel
Fluorescein angiography has been so far the gold-standard test to assess diabetic macular ischemia (DMI), a cause of irreversible visual impairment in diabetic patients. The aim of this study was to investigate foveal avascular zone (FAZ) and perifoveal microcirculation changes in eyes with nonproliferative diabetic retinopathy (NPDR) using optical coherence tomography angiography (OCTA), a new and noninvasive vascular imaging technique.Cross-sectional study including eyes of diabetic patients with NPDR.All patients underwent medical history, best-corrected visual acuity (BCVA) measurement, slit-lamp and fundus examination, multicolor imaging, SD-OCT, and swept-source OCT...
April 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28388705/retinal-microvasculature-and-visual-acuity-in-eyes-with-branch-retinal-vein-occlusion-imaging-analysis-by-optical-coherence-tomography-angiography
#11
Taku Wakabayashi, Tatsuhiko Sato, Chikako Hara-Ueno, Yoko Fukushima, Kaori Sayanagi, Nobuhiko Shiraki, Miki Sawa, Yasushi Ikuno, Hirokazu Sakaguchi, Kohji Nishida
Purpose: To investigate microvascular changes in the superficial capillary plexus (SCP) and deep capillary plexus (DCP) in eyes with resolved branch retinal vein occlusion (BRVO) and their association with best-corrected visual acuity (BCVA). Methods: Eighty-five eyes (82 consecutive patients) with BRVO after resolution of the macular edema were retrospectively evaluated. All patients underwent optical coherence tomography angiography (OCTA) for assessment of microvascular changes, including capillary telangiectasia, microaneurysm, and disruption of the foveal avascular zone (FAZ)...
April 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28388703/quantitative-oct-angiography-of-the-retinal-microvasculature-and-the-choriocapillaris-in-myopic-eyes
#12
Mayss Al-Sheikh, Nopasak Phasukkijwatana, Rosa Dolz-Marco, Mansour Rahimi, Nicholas A Iafe, K Bailey Freund, SriniVas R Sadda, David Sarraf
Purpose: To study the retinal capillary microvasculature and the choriocapillaris (CC) in myopic eyes using quantitative optical coherence tomography angiography (OCTA) analysis. Methods: Macular OCTA images of 3 × 3 mm were obtained using the RTVue-XR Avanti with AngioVue. Quantitative measurements of the retinal capillary microvascular layers and the CC were analyzed using en face projection images. Vessel density and fractal dimension of the superficial and deep retinal capillary plexus, and area and density of flow reduction in the CC were analyzed, quantified, and compared with an age-matched control group...
April 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28384724/gap-in-capillary-perfusion-on-optical-coherence-tomography-angiography-associated-with-persistent-macular-edema-in-branch-retinal-vein-occlusion
#13
Kotaro Tsuboi, Yuichiro Ishida, Motohiro Kamei
Purpose: To evaluate correlations between persistent macular edema associated with branch retinal vein occlusion (BRVO) and the macular perfusion status in the superficial capillary plexus (SCP) and deep capillary plexus (DCP) using optical coherence tomography angiography (OCTA). Methods: Retrospective, case-control study. Twenty patients with BRVO followed for 12 months or more were enrolled. Persistent macular edema was defined as central retinal thickness exceeding 300 μm that persisted or recurred less than 3 months after the final treatment...
April 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28384676/microscope-integrated-optical-coherence-tomography-angiography-in-the-operating-room-in-young-children-with-retinal-vascular-disease
#14
Xi Chen, Christian Viehland, Oscar M Carrasco-Zevallos, Brenton Keller, Lejla Vajzovic, Joseph A Izatt, Cynthia A Toth
Importance: Intraoperative optical coherence tomography (OCT) has gained traction as an important adjunct for clinical decision making during vitreoretinal surgery, and OCT angiography (OCTA) has provided novel insights in clinical evaluation of retinal diseases. To date, these two technologies have not been applied in combination to evaluate retinal vascular disease in the operating suite. Objective: To conduct microscope-integrated, swept-source OCTA (MIOCTA) in children with retinal vascular disease...
April 6, 2017: JAMA Ophthalmology
https://www.readbyqxmd.com/read/28380651/-optical-coherence-tomography-angiography-in-diagnosis-and-post-treatment-assessment-of-hemangioblastomas-in-hippel-lindau-disease
#15
S J Lang, C Evers, B Cakir, F Ludwig, C Lange, H Agostini
Background Optical coherence tomography angiography (OCTA) offers the possibility to visualize, non-invasively, blood vessels of the retina. In vascular tumors, especially hemangioblastomas in Hippel-Lindau disease, new information can be obtained with OCTA concerning structure of the tumor, tumor activity and treatment success. Patients Ten eyes of 10 patients with retinal hemangioblastoma in Hippel-Lindau disease were included. The age of the patients ranged from 19 years to 65 years (median 44 years). Results A total of 10 active and one inactive hemangioblastomas were examined with OCTA...
April 5, 2017: Klinische Monatsblätter Für Augenheilkunde
https://www.readbyqxmd.com/read/28377823/optical-coherence-tomography-and-optical-coherence-tomography-angiography-in-monitoring-coats-disease
#16
Wojciech Hautz, Joanna Gołębiewska, Beata Kocyła-Karczmarewicz
Purpose. The aim of this study was to evaluate the usefulness of optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) in monitoring pediatric patients with Coats' disease. Material and Methods. This retrospective study included 9 Caucasian patients receiving treatment for Coats' disease at the Children's Memorial Health Institute Ophthalmology Department between December 2014 and May 2016. The course of the disease was monitored with OCTA in combination with OCT and fluorescein angiography (FA)...
2017: Journal of Ophthalmology
https://www.readbyqxmd.com/read/28373438/liposomes-incorporating-transferrin-and-stearic-acid-modified-octa-arginine-for-sirna-delivery
#17
Dongsheng Yang, Xuewei Yang, Robert J Lee, Songcai Liu, Jing Xie
Liposomes incorporating stearic acid-modified octa-arginine (StA-R8) and conjugated to transferrin (Tf) were synthesized and evaluated for delivery of small interfering RNA (siRNA) against survivin. Characteristics, cytotoxicity, cellular uptake and biological activity of liposomes complexed to survivin siRNA were investigated. Tf-conjugated liposomes were shown to have reduced cytotoxicity and improved delivery efficiency for siRNA into cancer cells compared to non-conjugated StA-R8 liposomes. These data suggest that Tf-conjugated StA-R8 liposomes are promising vehicles for siRNA delivery in cancer therapy...
April 2017: Anticancer Research
https://www.readbyqxmd.com/read/28368976/optical-coherence-tomography-angiography-to-distinguish-choroidal-neovascularization-from-macular-inflammatory-lesions-in-multifocal-choroiditis
#18
Polina Astroz, Alexandra Miere, Sarah Mrejen, Rim Sekfali, Eric H Souied, Camille Jung, Sylvia Nghiem-Buffet, Salomon Y Cohen
PURPOSE: To characterize the macular lesions in multifocal choroiditis using multimodal imaging (MMI) and to evaluate optical coherence tomography angiography (OCTA) in distinguishing neovascular from inflammatory lesions. METHODS: Retrospective review of medical records of consecutive patients diagnosed with multifocal choroiditis and macular involvement, between September 2014 and May 2016, were included. All patients underwent standard examination and MMI, including fundus color photography, fundus autofluorescence, fluorescein angiography, and spectral domain optical coherence tomography...
March 30, 2017: Retina
https://www.readbyqxmd.com/read/28364338/assessment-of-choroidal-osteoma-complicating-choroidal-neovascularization-by-optical-coherence-tomography-angiography
#19
Ceying Shen, Shu Yan, Min Du, Hong Zhao, Ling Shao, Yibo Hu
PURPOSE: Choroidal osteoma (CO) frequently leads to progressive visual loss due to complications of secondary choroidal neovascularization (CNV).We report herein the function of optical coherence tomography angiography (OCTA) in observation of CO complicating CNV. METHODS: A 25-year-old female presented to our hospital with chief complaint of sudden unilateral visual acuity decrease for one week, with metamorphopsia in the left eye. Her best corrected visual acuity was 0...
March 31, 2017: International Ophthalmology
https://www.readbyqxmd.com/read/28362051/deep-capillary-macular-perfusion-indices-obtained-with-oct-angiography-correlate-with-degree-of-nonproliferative-diabetic-retinopathy
#20
Kumar Sambhav, Khaled K Abu-Amero, Kakarla V Chalam
PURPOSE: To evaluate the integrity of macular and temporomacular vasculature in nonproliferative diabetic retinopathy (NPDR) with noninvasive optical coherence tomography angiography (OCTA) and correlate perfusion indices with degree of NPDR. METHODS: In this prospective observational cross-sectional study, 102 eyes with newly diagnosed NPDR (mild NPDR, 36; moderate NPDR, 21; severe NPDR, 13; NPDR with diabetic macular edema [DME], 32) underwent OCTA. Sixty eyes of normal subjects served as control...
March 27, 2017: European Journal of Ophthalmology
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