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Somnath Narayan Karad, Heena Panchal, Christopher Clarke, William Lewis, Hon Wai Lam
The enantioselective synthesis of highly functionalized chiral cyclopent-2-enones by the reaction of alkynyl malonate esters with arylboronic acids is described. These desymmetrizing arylative cyclizations are catalyzed by a chiral phosphinooxazoline-nickel complex, and cyclization is enabled by the reversible E/Z isomerization of alkenylnickel species. The general methodology is also applicable to the synthesis of 1,6-dihydropyridin-3(2H)-ones.
May 16, 2018: Angewandte Chemie
Jing Yu, Yi Feng Zhu, Mei Xia Dai, Xia Lin, Shuo Qian Mao
Utilizing the plankton 1 (505 Μm), 2 (160 Μm), 3 (77 Μm) nets to seasonally collect zooplankton samples at 10 stations and the corresponding abundance data was obtained. Based on individual zooplankton biovolume, size groups were classified to test the changes in spatiotemporal characteristics of both Sheldon and normalized biovolume size spectra in thermal discharge seawaters near the Guohua Power Plant, so as to explore the effects of temperature increase on zooplankton size spectra in the seawaters. The results showed that the individual biovolume of zooplankton ranged from 0...
May 18, 2017: Ying Yong Sheng Tai Xue Bao, the Journal of Applied Ecology
Kui Zhang, Lingchao Cai, Zhongyue Yang, K N Houk, Ohyun Kwon
A novel bridged [2.2.1] bicyclic phosphine oxide, devised to circumvent the waste generation and burdens of purification that are typical of reactions driven by the generation of phosphine oxides, has been prepared in three steps from commercially available cyclopent-3-ene-1-carboxylic acid. The performance of this novel phosphine oxide was superior to those of current best-in-class counterparts, as verified experimentally through kinetic analysis of its silane-mediated reduction. It has been applied successfully in halide-/base-free catalytic γ-umpolung addition-Wittig olefinations of allenoates and 2-amidobenzaldehydes to produce 1,2-dihydroquinolines with good efficiency...
February 21, 2018: Chemical Science
Olga Schmidt
The present study contributes to the knowledge of the Indo-Pacific genus Visiana Swinhoe based on historic specimens collected in Indonesia and deposited in the collections of the Natural History Museum (London, UK) and Naturalis Biodiversity Center (Leiden, the Netherlands). Two new species V. cyclopsensis, sp. nov. from the Cyclops Mountains (West Papua) and V. minahasensis, sp. nov. from Minahasa (Sulawesi) are described and illustrated. These belong to two different species groups. An updated checklist of the genus Visiana, comprising 18 species is included...
January 2, 2018: Zootaxa
Sheng-Xing Long, Paul B Hamilton, Yang Yang, Sai Wang, Wen-da Huang, Chuan Chen, Ran Tao
Mercury (Hg) contamination in aquatic systems remains a global concern with the biomagnification of methylmercury (MeHg) through primary consumers (zooplankton) to fish and humans. In this study, total mercury (THg) and MeHg concentrations were analyzed in zooplankton collected from Baihua reservoir (Guizhou Province, China). Our results demonstrated that THg and MeHg concentrations were strongly correlated to zooplankton community and biomass composition. The THg concentration was significantly higher in micro-zooplankton compared to meso-zooplankton and macro-zooplankton, and MeHg concentration increased significantly as body size increased...
August 2018: Environmental Pollution
Julien Buendia, Zong Chang, Hendrik Eijsberg, Régis Guillot, Angelo Frongia, Francesco Secci, Juan Xie, Sylvie Robin, Thomas Boddaert, David J Aitken
We describe a photochemical reaction using two starting materials, a cyclopent-2-enone and an alkene, which are transformed in a controlled manner via the initial [2+2]-photocycloaddition adducts into cyclobutene aldehydes (conveniently trapped as stable acetals) or unprecedented angular tricyclic 4:4:4 oxetane-containing skeletons. These compounds are formed through tandem or triple cascade photochemical reaction processes, respectively. Small libraries of each compound class were prepared, thus suggesting that this photochemistry approach opens new opportunities for synthesis design and for widening molecular diversity...
May 28, 2018: Angewandte Chemie
Yan Zhai, Henk J Busscher, Yong Liu, Zhenkun Zhang, Theo G van Kooten, Linzhu Su, Yumin Zhang, Jinjian Liu, Jianfeng Liu, Yingli An, Linqi Shi
Inadvertent photosensitizer-activation and singlet-oxygen generation hampers clinical application of photodynamic therapies of superficial tumors or subcutaneous infections. Therefore, a reversible photoswitchable system was designed in micellar nanocarriers using ZnTPP as a photosensitizer and BDTE as a photoswitch. Singlet-oxygen generation upon irradiation didnot occur in closed-switch micelles with ZnTPP/BDTE feeding ratios >1:10. Deliberate switch closure/opening within 65-80 min was possible through thin layers of porcine tissue in vitro, increasing for thicker layers...
April 3, 2018: Biomacromolecules
Tonghao Yang, Xing Fan, Xiaopeng Zhao, Wei Yu
This paper reports that tertiary α-azidyl phenyl ketones can be transformed into enamides by treatment with FeBr2 at elevated temperature in DMF. The reaction proceeds via 1,2-benzoyl migration from α-carbon to the nitrogen atom, accompanied by expulsion of a nitrogen molecule. This protocol is suitable for the synthesis of N-(cyclopent-1-en-1-yl)benzamides, N-(cyclohex-1-en-1-yl)benzamides, and N-benzoyl-α-methyl enamines and provides a convenient approach toward isoquinolones.
April 6, 2018: Organic Letters
Hervé Ouanezar, William G Blakeney, Charles Latrobe, Adnan Saithna, Levi Reina Fernandes, Jean Romain Delaloye, Mathieu Thaunat, Bertrand Sonnery-Cottet
PURPOSE: Repairs of the posterior horn of the lateral meniscus can be technically challenging. In contrast to medial meniscus repairs, the capsule around the posterior segment attachment of the lateral meniscus is quite thin. This study evaluates the clinical results of an arthroscopic all-inside repair technique for unstable, vertical, lateral meniscus tears, using a suture repair placed directly into the popliteus tendon. METHODS: A retrospective analysis of prospectively collected data from the SANTI database was performed...
March 3, 2018: Knee Surgery, Sports Traumatology, Arthroscopy: Official Journal of the ESSKA
Issa Diédhiou, Diaga Diouf
Root endosymbioses are mutualistic interactions between plants and the soil microorganisms (Fungus, Frankia or Rhizobium) that lead to the formation of nitrogen-fixing root nodules and/or arbuscular mycorrhiza. These interactions enable many species to survive in different marginal lands to overcome the nitrogen-and/or phosphorus deficient environment and can potentially reduce the chemical fertilizers used in agriculture which gives them an economic, social and environmental importance. The formation and the development of these structures require the mediation of specific gene products among which the transcription factors play a key role...
February 15, 2018: World Journal of Microbiology & Biotechnology
Rafael F A Gomes, Nuno R Esteves, Jaime A S Coelho, Carlos A M Afonso
trans-4,5-Diamino-cyclopent-2-enones (CP) are usually prepared by Lewis acid-catalyzed condensation of furfural and a secondary amine in an organic solvent. The reaction proceeds through the formation of a Stenhouse salt (SS) intermediate followed by an electrocyclization reaction to afford the desired CP. Herein, we described the use of Cu(OTf)2 as a very efficient catalyst for the synthesis of CP in water at room temperature. Furthermore, the mild reaction conditions, catalyst reusability, and outstanding functional group tolerance suggest that this CP platform can be further used in chemical biology...
February 9, 2018: Journal of Organic Chemistry
Hong-Xia Ren, Lin Peng, Xiang-Jia Song, Li-Guo Liao, Ying Zou, Fang Tian, Li-Xin Wang
A novel and diastereoselective [3 + 2] annulation of isoindigos and Morita-Baylis-Hillman carbonates has been developed for the highly efficient and one-step preparation of highly steric dispiro[cyclopent-3'-ene]bisoxindoles with two all-carbon quaternary spirocenters and three adjacent cycles in excellent yields (up to >99%) and diastereoselectivities (up to >20 : 1) under mild conditions within a few minutes. A series of dispiro[cyclopent-3'-ene]bisoxindoles were obtained and scale-up experiment was conducted with excellent results demonstrating the potential applications of this protocol...
February 21, 2018: Organic & Biomolecular Chemistry
Jose I Juncosa, Kenji Takaya, Hoang V Le, Matthew J Moschitto, Pathum M Weerawarna, Romila Mascarenhas, Dali Liu, Stephen L Dewey, Richard B Silverman
γ-Aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the central nervous system. Inhibition of GABA aminotransferase (GABA-AT), a pyridoxal 5'-phosphate (PLP)-dependent enzyme that degrades GABA, has been established as a possible strategy for the treatment of substance abuse. The raised GABA levels that occur as a consequence of this inhibition have been found to antagonize the rapid release of dopamine in the ventral striatum (nucleus accumbens) that follows an acute challenge by an addictive substance...
February 14, 2018: Journal of the American Chemical Society
Hua Wu, Qian Wang, Jieping Zhu
A copper-catalyzed enantioselective arylative desymmetrization of prochiral cyclopentenes with diaryliodonium salts was developed. In the presence of a catalytic amount of a chiral copper-bisoxazoline complex, which was generated in situ, the reaction of 4-substituted or 4,4-disubstituted cyclopent-1-enes with diaryliodonium hexafluoroarsenates afforded the chiral arylated products in good yields with excellent enantioselectivity. A cyclohexyl-containing Box ligand was essential for the high enantioselectivity...
March 1, 2018: Angewandte Chemie
Katarina Teresa Wishart, Dorrit Winterholer, Inja Bogdan, Elmar Fritsche
No abstract text is available yet for this article.
December 2017: Handchirurgie, Mikrochirurgie, Plastische Chirurgie
Mark A Klaassen, Jerry L Aikins
The cyclops lesion is a localized anterior arthrofibrosis most commonly seen following anterior cruciate ligament reconstruction. The lesion forms at the anterior cruciate ligament insertion creating a painful extension block between femoral intercondylar notch and tibial plateau. We present 2 cases (3 knees) in which cyclops lesions appeared atypically following bicruciate-retaining total knee replacement. Two lesions occurred in a single patient following bilateral knee replacement. One lesion occurred in an active sportswoman...
December 2017: Arthroplasty Today
Valérie Dupé, Christèle Dubourg, Marie de Tayrac, Véronique David
No abstract text is available yet for this article.
November 2017: Médecine Sciences: M/S
Hervé Ouanezar, William G Blakeney, Levi Reina Fernandes, Amrut Borade, Charles Latrobe, Eduardo Frois Temponi, Bertrand Sonnery-Cottet
PURPOSE: The primary aim of this study was to evaluate the functional outcomes, knee stability, complications, and reoperations associated with anatomic anterior cruciate ligament (ACL) reconstruction using the single anteromedial bundle biological augmentation (SAMBBA) technique in a consecutive series of 128 patients with a minimum follow-up of 24 months. A secondary aim was to compare larger preserved ACL remnants with smaller preserved remnants. METHODS: Patients who underwent primary anatomic ACL reconstruction using the SAMBBA technique from July 2013 to October 2014 were analyzed...
March 2018: Arthroscopy: the Journal of Arthroscopic & related Surgery
Dugald Reid, Huijun Liu, Simon Kelly, Yasuyuki Kawaharada, Terry Mun, Stig U Andersen, Guilhem Desbrosses, Jens Stougaard
Establishment of symbiotic nitrogen-fixation in legumes is regulated by the plant hormone ethylene, but it has remained unclear whether and how its biosynthesis is regulated by the symbiotic pathway. We established a sensitive ethylene detection system for Lotus japonicus and found that ethylene production increased as early as 6 hours after inoculation with Mesorhizobium loti This ethylene response was dependent on Nod factor production by compatible rhizobia. Analyses of nodulation mutants showed that perception of Nod factor was required for ethylene emission, while downstream transcription factors including CYCLOPS, NIN, and ERN1 were not required for this response...
February 2018: Plant Physiology
Georgios I Ioannou, Tamsyn Montagnon, Dimitris Kalaitzakis, Spiros A Pergantis, Georgios Vassilikogiannakis
A series of hydroxycyclopent-2-enones and methoxycyclopent-2-enones have been synthesized in a single operation from simple furan substrates using an innovative continuous flow nebulizer system (NebPhotOX). Photooxygenation of the furan substrates takes place in an aerosol within the NebPhotOX system.
December 13, 2017: Organic & Biomolecular Chemistry
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