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https://www.readbyqxmd.com/read/28938249/absence-of-fitness-improvement-is-associated-with-outcomes-in-heart-failure-patients
#1
Esmée A Bakker, Johan A Snoek, Esther P Meindersma, Maria T E Hopman, Louise Bellersen, André L M Verbeek, Dick H J Thijssen, Thijs M H Eijsvogels
PURPOSE: To examine the clinical impact of cardiorespiratory fitness (CRF) and improvements in CRF after cardiac rehabilitation (CR) in heart failure (HF) patients for their risk of all-cause mortality and unplanned hospitalization. Secondly, to investigate possible factors associated with the absence of improvement in CRF after rehabilitation. METHODS: We included 155 HF patients receiving CR between October 2009 and January 2015. Patients performed an incremental bicycle test to assess CRF through peak oxygen uptake (VO2-peak) before and after CR-based supervised exercise training...
September 21, 2017: Medicine and Science in Sports and Exercise
https://www.readbyqxmd.com/read/28937679/total-synthesis-of-tubingensin-b-enabled-by-the-strategic-use-of-an-aryne-cyclization
#2
Michael A Corsello, Junyong Kim, Neil K Garg
Tubingensin B is an indole diterpenoid that bears a daunting chemical structure featuring a disubstituted carbazole unit, five stereogenic centres-three of which are quaternary-and a decorated [3.2.2]-bridged bicycle. We describe our synthetic design toward a concise and enantiospecific total synthesis of tubingensin B, which hinges on the strategic use of a transient aryne intermediate. Although initial studies led to unexpected reaction outcomes, we ultimately implemented a sequence of carbazolyne cyclization followed by Rh-catalysed fragmentation to install the seven-membered ring and vicinal quaternary stereocentres of the natural product...
October 2017: Nature Chemistry
https://www.readbyqxmd.com/read/28934321/identifying-the-factors-affecting-bike-sharing-usage-and-degree-of-satisfaction-in-ningbo-china
#3
Yanyong Guo, Jibiao Zhou, Yao Wu, Zhibin Li
The boom in bike-sharing is receiving growing attention as societies become more aware of the importance of active non-motorized traffic modes. However, the low usage of this transport mode in China raises concerns. The primary objective of this study is to explore factors affecting bike-sharing usage and satisfaction degree of bike-sharing among the bike-sharing user population in China. Data were collected by a questionnaire survey in Ningbo. A bivariate ordered probit (BOP) model was developed to examine simultaneously those factors associated with both bike-sharing usage and satisfaction degree of bike-sharing among users...
2017: PloS One
https://www.readbyqxmd.com/read/28932481/the-7-aza-norbornane-nucleus-of-epibatidine-7-aza-bicyclo-2-2-1-heptan-7-ium-chloride
#4
Sergey N Britvin, Andrey M Rumyantsev
7-Aza-bicyclo-[2.2.1]heptane (7-aza-norbornane) is a bridged heterocyclic nucleus found in epibatidine, the alkaloid isolated from the skin of the tropical poison frog Epipedobates tricolor. Since epibatidine is known as one of the most potent acetyl-choline nicotinic receptor agonists, a plethora of literature has been devoted to this alkaloid. However, there are no structural data on the unsubstituted 7-aza-norbornane, the parent bicyclic ring of epibatidine and its derivatives. We herein present the structural characterization of the 7-aza-bicyclo-[2...
September 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/28932474/crystal-structures-of-two-bi-cyclo-5-1-0-octa-nes-potassium-trans-bi-cyclo-5-1-0-octane-4-carboxyl-ate-monohydrate-and-cis-bi-cyclo-5-1-0-octan-4-yl-4-bromo-benzene-sulfonate
#5
Peter W R Corfield, Richard A Kershaw
The crystal structures of the trans-fused compound potassium trans-bi-cyclo-[5.1.0]octane-4-carboxyl-ate monohydrate, K(+)·C9H13O2(-)·H2O, (I), and of cis-bi-cyclo-[5.1.0]octan-4-yl 4-bromo-benzene-sulfonate, C14H17BrO3S, (II), have been determined. Compound (I) represents the smallest trans-fused cyclo-propane structure known to date, and features the expected shortening of the bridging C-C bond relative to the other cyclo-propane bond lengths, in contrast to the cis-fused system, (II), where all of the cyclo-propane bond lengths are the same...
September 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/28932445/structural-elucidation-of-a-hy-droxy-cineole-product-obtained-from-cytochrome-p450-monooxygenase-cyp101j2-catalysed-transformation-of-1-8-cineole
#6
Gavin E Collis, Birgit Unterweger, Geoff J Dumsday, Craig M Forsyth
1,8-Cineole is an abundant natural product that has the potential to be transformed into other building blocks that could be suitable alternatives to petroleum-based chemicals. Mono-hydroxy-lation of 1,8-cineole can potentially occur at eight different carbon sites around the bicyclic ring system. Using cytochrome P450 monooxygenase CYP101J2 from Sphingobium yanoikuyae B2, the hy-droxy-lation can be regioselectively directed at the C atom adjacent to the methyl-substituted quaternary bridgehead atom of 1,8-cineole...
July 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/28929941/long-term-predictors-of-stroke-in-healthy-middle-aged-men
#7
Erik Prestgaard, Christian Hodnesdal, Kristian Engeseth, Jan Erikssen, Johan Bodegård, Knut Liestøl, Knut Gjesdal, Sverre E Kjeldsen, Irene Grundvold, Eivind Berge
Background There are few data on risk factors for stroke during long-term follow-up of healthy individuals. Aims We aimed to investigate the long-term predictive impact on stroke risk of baseline variables including hemodynamic variables measured at rest and during exercise in middle-aged, healthy men. Methods We performed a prospective cohort study of 2014 healthy Norwegian men aged 40-59 years, recruited during the period 1972-1975 and followed until 2007. Participants underwent a comprehensive clinical assessment at baseline, including a bicycle exercise test...
January 1, 2017: International Journal of Stroke: Official Journal of the International Stroke Society
https://www.readbyqxmd.com/read/28929559/-4-3-cycloaddition-reactions-of-n-alkyl-oxidopyridinium-ions
#8
Chencheng Fu, Nestor Lora, Patrick L Kirchhoefer, Dong Reyoul Lee, Erich Altenhoefer, Natasha L Hungerford, Elizabeth H Krenske, Michael Harmata
N-Methylation of methyl 5-hydroxynicotinate followed by reaction with a diene in the presence of triethylamine afforded (4+3)-cycloadducts in good to excellent yields. High regioselectivity was exhibited with 1-substituted and 1,2-disubstituted butadienes. Density functional theory calculations indicate that the cycloaddition involves concerted addition of the diene onto the oxidopyridinium ion. The process provides rapid access to bicyclic nitrogenous structures resembling natural alkaloids.
September 19, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28925533/stereospecific-reaction-of-donor-acceptor-cyclopropanes-with-thioketones-a-novel-access-to-highly-substituted-tetrahydrothiophenes
#9
Daniel B Werz, André Augustin, Peter G Jones, Maximilian Sensse
Lewis-acid-catalyzed reactions of 2-substituted cyclopropane 1,1-dicarboxylates with thioketones are described. Highly substituted tetrahydrothiophenes with two adjacent quaternary carbon atoms were obtained in a stereospecific manner under mild conditions and in high yield using AlCl3 as Lewis acid. Moreover, an intramolecular approach was successfully implemented to gain access to sulfur-bridged [n.2.1] bicyclic ring systems. Conversion of selenoketones, the heavier analogs, under similar conditions resulted in the formation of various tetrahydroselenophenes...
September 19, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28925514/a-one-step-germole-to-silole-transformation-and-a-stable-isomer-of-a-disilabenzene
#10
Thomas Müller, Crispin Reinhold, Zhaowen Dong, Jan Winkler, Henning Steinert, Marc Schmidtmann
An unusual germole-to-silole transformation is described. As key intermediates hetero-fulvenes are formed which rearrange to more stable bicyclic carbene analogues. The so-formed germylenes undergo a reductive elimination yielding elemental germanium and siloles. In contrast, the analogous silylenes are stable at ambient conditions and were identified by MS spectrometry and NMR spectroscopy supported by the results of quantum mechanical calculations. These bicyclic silylenes are stable derivatives of the global minimum of the C4Si2H6 potential energy surface...
September 19, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28923961/evolution-of-the-3-hydroxypropionate-bicycle-and-recent-transfer-of-anoxygenic-photosynthesis-into-the-chloroflexi
#11
Patrick M Shih, Lewis M Ward, Woodward W Fischer
Various lines of evidence from both comparative biology and the geologic record make it clear that the biochemical machinery for anoxygenic photosynthesis was present on early Earth and provided the evolutionary stock from which oxygenic photosynthesis evolved ca. 2.3 billion years ago. However, the taxonomic identity of these early anoxygenic phototrophs is uncertain, including whether or not they remain extant. Several phototrophic bacterial clades are thought to have evolved before oxygenic photosynthesis emerged, including the Chloroflexi, a phylum common across a wide range of modern environments...
September 18, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28923517/bicycle-helmet-use-patterns-in-italy-a-description-and-analysis-of-survey-data-from-an-italian-friends-of-cycling-association
#12
Ioana Popa, Ottavia E Ferraro, Chiara Orsi, Anna Morandi, Cristina Montomoli
Cycling is becoming one of the most popular forms of recreation and transport the world over, but cyclists still have a high level of vulnerability. A bicycle helmet is an important safety device available to cyclists, but little is known regarding possible determinants of helmet use among adults. This study aims at providing information on helmet usage patterns in Italy and identifying the factors associated with bicycle helmet use. Data on 2072 bicycle riders from an Italian friends of cycling association aged 18 years or older who had ridden a bicycle in the last month were collected using an ad-hoc questionnaire via the web...
September 15, 2017: Accident; Analysis and Prevention
https://www.readbyqxmd.com/read/28918531/penetrating-orbital-trauma-leading-to-trans-orbital-brain-herniation
#13
Siddharth Vankipuram, Chittij Srivastava, B K Ojha, Sushant Sahoo
INTRODUCTION: Development of a posttraumatic herniation of brain parenchyma through the orbit is a rare complication of orbital roof fracture. Mostly, the injury is due to a direct impact to the frontal region resulting in orbital roof fracture with dural defect and herniation of cerebrospinal fluid or brain parenchyma. These patients present with acute or gradually progressive proptosis with impending risk of loss of vision and mandate surgical decompression of optic nerve with watertight closure of the dural defect...
September 16, 2017: Child's Nervous System: ChNS: Official Journal of the International Society for Pediatric Neurosurgery
https://www.readbyqxmd.com/read/28917096/how-bicycle-level-of-traffic-stress-correlate-with-reported-cyclist-accidents-injury-severities-a-geospatial-and-mixed-logit-analysis
#14
Chen Chen, Jason C Anderson, Haizhong Wang, Yinhai Wang, Rachel Vogt, Salvador Hernandez
Transportation agencies need efficient methods to determine how to reduce bicycle accidents while promoting cycling activities and prioritizing safety improvement investments. Many studies have used standalone methods, such as level of traffic stress (LTS) and bicycle level of service (BLOS), to better understand bicycle mode share and network connectivity for a region. However, in most cases, other studies rely on crash severity models to explain what variables contribute to the severity of bicycle related crashes...
September 13, 2017: Accident; Analysis and Prevention
https://www.readbyqxmd.com/read/28916639/small-rna-seq-during-acute-maximal-exercise-reveal-rnas-involved-in-vascular-inflammation-and-cardiometabolic-health
#15
Ravi Shah, Ashish S Yeri, Avash Das, Amanda Courtright-Lim, Olivia Ziegler, Ernest Gervino, Jeffrey Ocel, Pablo Quintero Pinzon, Luke Wooster, Cole Shields Bailey, Kahraman Tanriverdi, Lea Beaulieu, Jane E Freedman, Ionita Ghiran, Gregory D Lewis, Kendall Van Keuren-Jensen, Saumya Das
OBJECTIVE: Exercise improves cardiometabolic and vascular function, though mechanisms remain unclear. Our objective was to demonstrate the diversity of circulating extracellular RNA (ex-RNA) release during acute exercise in humans and its relevance to exercise-mediated benefits on vascular inflammation. Approach and Results: We performed plasma small RNA sequencing (RNA-seq) in 26 individuals undergoing symptom-limited maximal treadmill exercise, with replication of our top candidate miRNA in a separate cohort of 59 individuals undergoing bicycle ergometry...
September 15, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28914359/changes-in-acid-base-and-ion-balance-during-exercise-in-normoxia-and-normobaric-hypoxia
#16
Olaf Lühker, Marc Moritz Berger, Alexander Pohlmann, Lorenz Hotz, Tilmann Gruhlke, Marcel Hochreiter
PURPOSE: Both exercise and hypoxia cause complex changes in acid-base homeostasis. The aim of the present study was to investigate whether during intense physical exercise in normoxia and hypoxia, the modified physicochemical approach offers a better understanding of the changes in acid-base homeostasis than the traditional Henderson-Hasselbalch approach. METHODS: In this prospective, randomized, crossover trial, 19 healthy males completed an exercise test until voluntary fatigue on a bicycle ergometer on two different study days, once during normoxia and once during normobaric hypoxia (12% oxygen, equivalent to an altitude of 4500 m)...
September 15, 2017: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/28911142/deficient-endogenous-glucose-production-during-exercise-after-total-pancreatectomy-islet-autotransplantation
#17
Lindsey D Bogachus, Elizabeth Oseid, Melena Bellin, Adrian Vella, R Paul Robertson
Context: Total pancreatectomy followed by intrahepatic islet autotransplantation (TP/IAT) is performed to alleviate severe, unrelenting abdominal pain caused by chronic pancreatitis, to improve quality of life, and to prevent diabetes. Objective: To determine the cause of exercise-induced hypoglycemia that is a common complaint in TP/IAT recipients. Design: Participants completed 1 hour of steady-state exercise. Setting: Hospital research unit...
September 1, 2017: Journal of Clinical Endocrinology and Metabolism
https://www.readbyqxmd.com/read/28910119/nbcl5-zn-pcy3-system-catalyzed-intramolecular-2-2-2-cycloadditions-of-diynes-and-alkenes-to-form-bicyclic-cyclohexadienes
#18
Keisuke Watanabe, Yasushi Satoh, Motofumi Kamei, Hirohisa Furukawa, Maito Fuji, Yasushi Obora
A NbCl5, Zn, and PCy3 catalytic system that generated low-valent Nb species is used for the synthesis of bicyclic cyclohexadienes from diynes and simple alkenes. A phosphine ligand is important for stabilizing low-valent Nb in the cycloaddition. The bicyclic cyclohexadiene skeleton is important in transition-metal-catalyzed intramolecular cycloadditions.
September 14, 2017: Organic Letters
https://www.readbyqxmd.com/read/28910114/double-diels-alder-approach-to-maoecrystal-v-unexpected-c-c-bond-forming-fragmentations-of-the-2-2-2-bicyclic-core
#19
Brandon R Smith, Jon T Njardarson
Synthetic studies toward maoecrystal V are reported. An oxidative dearomatization/Diels-Alder cascade to assemble the natural product carbocyclic core in one step is proposed. A facile electrocyclization is shown to suppress the intramolecular allene Diels-Alder pathway. This obstacle is alleviated via a stepwise approach with an allene equivalent to access the key cyclopentadiene-fused [2.2.2]-bicyclic core. Upon treatment with Lewis acid, the proposed intramolecular hetero-Diels-Alder reaction is cleanly and unexpectedly diverted either via C-C bond-forming fragmentation to the spiro-indene product (when R = OMe) or via elimination (when R = H)...
September 14, 2017: Organic Letters
https://www.readbyqxmd.com/read/28905970/on-the-discovery-of-new-potent-human-farnesyltransferase-inhibitors-emerging-pyroglutamic-derivatives
#20
Germain Homerin, Emmanuelle Lipka, Benoît Rigo, Amaury Farce, Joëlle Dubois, Alina Ghinet
In the current context of lack of emergence of innovative human farnesyltransferase inhibitors families, and given all new therapeutic perspectives that open up for such molecules in rare diseases (e.g. Hutchinson-Gilford progeria syndrome), and in delta hepatitis, cardiovascular or neuroinflammatory diseases, we have just discovered a new series of powerful inhibitors. These molecules are pyroglutamic acid derivatives, and were evaluated on human farnesyltransferase in vitro then modeled in silico on the active site of the protein...
September 14, 2017: Organic & Biomolecular Chemistry
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