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https://www.readbyqxmd.com/read/28225179/frozen-chirality-of-tertiary-aromatic-amides-access-to-enantioenriched-tertiary-%C3%AE-amino-acid-or-amino-alcohol-without-any-chiral-reagent
#1
Thi Thoa Mai, Baby Viswambharan, Didier Gori, Régis Guillot, Jean-Valère Naubron, Cyrille Kouklovsky, Valérie Alezra
One of the fundamental and intriguing aspects of life is the homochirality of the essential molecules. In this field, the absolute asymmetric synthesis of α-amino acids is a major challenge. Herein we report access, by chemical means, to tertiary α-amino acids derivatives in up to 96% ee without using any chiral reagent. In our strategy, the dynamic axial chirality of tertiary aromatic amides is frozen in a crystal and is responsible for the stereoselectivity of the subsequent steps. Furthermore, we are able to control the configuration of the final product by carefully sorting out the initial crystals...
February 22, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28209184/arterial-access-site-complications-after-use-of-a-vascular-closure-device-related-to-puncture-height
#2
Benjamin Sartorius, Michael Behnes, Melike Ünsal, Ursula Hoffmann, Siegfried Lang, Kambis Mashayekhi, Martin Borggrefe, Ibrahim Akin
BACKGROUND: To analyze differences of access-site complications related to the height of femoral arterial puncture and the use of a vascular closure device (VCD) following percutaneous coronary intervention (PCI). METHODS: A subgroup of the FERARI study being treated by femoral arterial access and valuable inguinal angiography before implantation of a VCD were included. Inguinal angiographies were systematically reviewed by two independent cardiologists to determine the correct height of femoral arterial puncture...
February 16, 2017: BMC Cardiovascular Disorders
https://www.readbyqxmd.com/read/28208728/parabens-accelerate-ovarian-dysfunction-in-a-4-vinylcyclohexene-diepoxide-induced-ovarian-failure-model
#3
Jae-Hwan Lee, Myeongho Lee, Changhwan Ahn, Hee Young Kang, Dinh Nam Tran, Eui-Bae Jeung
Parabens are widely used preservatives in basic necessities such as cosmetic and pharmaceutical products. In previous studies, xenoestrogenic actions of parabens were reported in an immature rat model and a rat pituitary cell line (GH3 cells). The relationship between parabens and ovarian failure has not been described. In the present study, the influence of parabens on ovarian folliculogenesis and steroidogenesis was investigated. A disruptor of ovarian small pre-antral follicles, 4-vinylcyclohexene diepoxide (VCD, 40 mg/kg), was used to induce premature ovarian failure (POF)...
February 8, 2017: International Journal of Environmental Research and Public Health
https://www.readbyqxmd.com/read/28190935/reassignment-of-the-absolute-configuration-of-plakinidone-from-the-sponge-consortium-plakortis-halichondrioides-xestospongia-deweerdtae-using-a-combination-of-synthesis-and-a-chiroptical-approach
#4
Carlos Jiménez-Romero, Joanna E Rode, Abimael D Rodríguez
Recent work by Wu et al. in connection with the first synthesis of the marine natural product plakinidone revealed that the most salient feature of its purported structure, a six-membered perlactone moiety, was in fact a five-membered lactone, i.e. a 3-methyl-4-hydroxy-2(5H)-furanone or tetronic acid ring. With the planar structure of plakinidone confidently revised, we undertook a new investigation to unambiguously establish its absolute configuration. Upon preparing two stable derivatives 1 and 5 from a sample of naturally occurring plakinidone extracted from the sponge association Plakortis halichondriodes-Xetospongia deweerdtae, the absolute configuration was assigned by synthesis and vibrational and electronic circular dichroism (VCD and ECD) measurements in combination with density functional theory calculations at the B3LYP/aug-cc-pVDZ/PCM(CH3CN) level of theory...
June 2016: Tetrahedron, Asymmetry
https://www.readbyqxmd.com/read/28178845/vibrational-circular-dichroism-spectra-for-large-molecules-and-molecules-with-heavy-elements
#5
Kevin Reiter, Michael Kühn, Florian Weigend
We present an implementation of vibrational circular dichroism (VCD) spectra in TURBOMOLE. We mainly followed the route proposed by Cheeseman [Chem. Phys. Lett. 252, 211 (1996)] and extended the modules for calculating the magnetic response and vibrational frequencies accordingly. The implementation allows for gauge origin invariant employment of effective core potentials, as demonstrated for Co(ppy)3, ppy = 2-Phenylpyridine. In this way, scalar relativistic effects are covered and heavy elements can be treated...
February 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28138511/strokog-stroke-and-cognition-consortium-an-international-consortium-to-examine-the-epidemiology-diagnosis-and-treatment-of-neurocognitive-disorders-in-relation-to-cerebrovascular-disease
#6
Perminder S Sachdev, Jessica W Lo, John D Crawford, Lisa Mellon, Anne Hickey, David Williams, Régis Bordet, Anne-Marie Mendyk, Patrick Gelé, Dominique Deplanque, Hee-Joon Bae, Jae-Sung Lim, Amy Brodtmann, Emilio Werden, Toby Cumming, Sebastian Köhler, Frans R J Verhey, Yan-Hong Dong, Hui Hui Tan, Christopher Chen, Xu Xin, Raj N Kalaria, Louise M Allan, Rufus O Akinyemi, Adesola Ogunniyi, Aleksandra Klimkowicz-Mrowiec, Martin Dichgans, Frank A Wollenweber, Vera Zietemann, Michael Hoffmann, David W Desmond, Thomas Linden, Christian Blomstrand, Björn Fagerberg, Ingmar Skoog, Olivier Godefroy, Mélanie Barbay, Martine Roussel, Byung-Chul Lee, Kyung-Ho Yu, Joanna Wardlaw, Stephen J Makin, Fergus N Doubal, Francesca M Chappell, Velandai K Srikanth, Amanda G Thrift, Geoffrey A Donnan, Nagaendran Kandiah, Russell J Chander, Xuling Lin, Charlotte Cordonnier, Solene Moulin, Costanza Rossi, Behnam Sabayan, David J Stott, J Wouter Jukema, Susanna Melkas, Hanna Jokinen, Timo Erkinjuntti, Vincent C T Mok, Adrian Wong, Bonnie Y K Lam, Didier Leys, Hilde Hénon, Stéphanie Bombois, Darren M Lipnicki, Nicole A Kochan
INTRODUCTION: The Stroke and Cognition consortium (STROKOG) aims to facilitate a better understanding of the determinants of vascular contributions to cognitive disorders and help improve the diagnosis and treatment of vascular cognitive disorders (VCD). METHODS: Longitudinal studies with ≥75 participants who had suffered or were at risk of stroke or TIA and which evaluated cognitive function were invited to join STROKOG. The consortium will facilitate projects investigating rates and patterns of cognitive decline, risk factors for VCD, and biomarkers of vascular dementia...
2017: Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring
https://www.readbyqxmd.com/read/28121978/a-vibrating-cold-device-to-reduce-pain-in-the-pediatric-emergency-department-a-randomized-clinical-trial
#7
Debra Ann Potts, Katherine Finn Davis, Okan U Elci, Joel A Fein
OBJECTIVE: Pain of intravenous (IV) catheter insertion can be mitigated with appropriate analgesia, thereby avoiding unnecessary distress. Our objective was to compare the self-reported pain of IV catheter insertion in children when using a vibrating cold device (VCD) versus standard of care 4% topical lidocaine cream (TL). METHODS: This was a 2-arm randomized controlled noninferiority trial with a convenience sample of 4- to 18-year-olds requiring nonemergent IV catheter insertion...
January 24, 2017: Pediatric Emergency Care
https://www.readbyqxmd.com/read/28118957/the-role-of-chirality-in-a-set-of-key-intermediates-of-pharmaceutical-interest-3-aryl-substituted-%C3%AE-butyrolactones-evidenced-by-chiral-hplc-separation-and-by-chiroptical-spectroscopies
#8
Daniela Rossi, Rita Nasti, Simona Collina, Giuseppe Mazzeo, Simone Ghidinelli, Giovanna Longhi, Maurizio Memo, Sergio Abbate
The enantiomers of four chiral 3-aryl-substituted-γ-butyrolactones, key intermediates for the preparation of compounds of pharmaceutical interest, were successfully isolated by enantioselective chromatography, employing the Chiralpak AD-H chiral stationary phase. For all compounds the same elution order was observed, as monitored by a full set of chiroptical methods that we employed, namely ORD (optical rotatory dispersion), ECD (electronic circular dichroism, or CD in the UV range), and VCD (vibrational circular dichroism, or CD in the IR range)...
January 5, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28103752/mynxgrip-for-closure-of-antegrade-puncture-after-peripheral-interventions-with-same-day-discharge
#9
Maciej J Pruski, Aleksandra M Blachut, Magda Konkolewska, Adam Janas, Eugeniusz Hrycek, Piotr P Buszman, Radoslaw S Kiesz
BACKGROUND: This was the first prospective study to assess the safety and efficiency of MynxGrip vascular closure device (VCD) in peripheral interventions with antegrade access. METHODS AND RESULTS: We enrolled 66 consecutive patients from 1 center. All patients were discharged home on the day of procedure and were observed for adverse events at 1 and 30 days of follow-up. No major complications were observed. The rate of minor complications (conversion to manual or mechanical compression) was 7...
January 1, 2017: Vascular and Endovascular Surgery
https://www.readbyqxmd.com/read/28079923/vibrational-circular-dichroism-of-a-2-5-diketopiperazine-dkp-peptide-evidence-for-dimer-formation-in-cyclo-ll-or-ld-diphenylalanine-in-the-solid-state
#10
Ariel Pérez-Mellor, Anne Zehnacker
The diastereomer diketopiperazine (DKP) peptides built on phenylalanine, namely, cyclo diphenylalanine LPhe-LPhe and LPhe-DPhe, were studied in the solid phase by vibrational circular dichroism (VCD) coupled to quantum chemical calculations. The unit structure of cyclo LPhe-LPhe in KBr pellets is a dimer bridged by two strong NH…O hydrogen bonds. The intense bisignate signature in the CO stretch region is interpreted in terms of two contributions arising from the free COs of the dimer and the antisymmetrical combination of the bound COs...
January 12, 2017: Chirality
https://www.readbyqxmd.com/read/28078764/photoisomerization-of-a-chiral-imine-molecular-switch-followed-by-matrix-isolation-vcd-spectroscopy
#11
Corina H Pollok, Tim Riesebeck, Christian Merten
Characterizing the stereochemistry of transient photoisomerization products remains a big challenge for the design of molecular machines, such as unidirectional molecular motors. Often these states are not stable long enough to be characterized in detail using conventional spectroscopic tools. The structurally simple camphorquinone imine 1 serves to illustrate the advantage of combining the matrix-isolation technique with vibrational circular dichroism (VCD) spectroscopy for the investigation of photoisomerizations of chiral molecules...
January 12, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28070081/structural-discrimination-between-a%C3%AE-1-40-and-a%C3%AE-1-42-peptides-in-films-with-vibrational-circular-dichroism-spectroscopy
#12
Toshinori Morisaku, Hiroharu Yui
The secondary structure of full-length Aβ(1-40) and Aβ(1-42) peptides in films has been investigated with IR and vibrational circular dichroism (VCD) spectroscopy. From IR spectra, it is shown that the prepared films of Aβ(1-40) and Aβ(1-42) mainly comprise the β-sheet conformation that is characteristic of aggregated and fibrous Aβ. In the VCD spectra, the Aβ(1-42) film shows an intense and sharp band with left-handed optical activity at around 1625 cm(-1), while the Aβ(1-40) film shows a weak and broad band with right-handed activity at around 1630 cm(-1)...
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
https://www.readbyqxmd.com/read/28054005/data-of-aromatase-inhibitors-alone-and-in-combination-with-raloxifene-on-microarchitecture-of-lumbar-vertebrae-and-strength-test-in-femoral-diaphysis-of-vcd-treated-ovotoxic-mice
#13
Abul Kalam, Sushama Talegaonkar, Divya Vohora
Currently, the third generation aromatase inhibitors are the drugs of choice for treatment of early and advanced breast cancer in postmenopausal women. The negative impact of these drugs on bone health is the significant limiting factor during this therapy. Here we report the effect of two aromatase inhibitors viz. letrozole and exemestane alone and in combination with raloxifene on lumbar vertebrae and femoral diaphysis after one month of treatment but no discernible effects were observed on bone when tested by micro CT and strength test except in trabecular number which was reduced in lumbar vertebrae following letrozole and exemestane...
February 2017: Data in Brief
https://www.readbyqxmd.com/read/28045273/analysis-of-configuration-and-conformation-of-furanose-ring-in-carbohydrate-and-nucleoside-by-vibrational-circular-dichroism
#14
Tohru Taniguchi, Kie Nakano, Ryosuke Baba, Kenji Monde
A reliable and convenient method for determining the configuration and conformation of the furanose ring in carbohydrates and nucleosides by vibrational circular dichroism (VCD) spectroscopy is described. Diastereomeric pairs of several furanose monosaccharides and nucleosides were prepared, and their VCD spectra were analyzed. The results revealed that VCD spectroscopy elucidates the equibrated state of the furanose ring puckers, which is often difficult to study by other techniques.
January 3, 2017: Organic Letters
https://www.readbyqxmd.com/read/28019704/isolation-of-the-major-chiral-compounds-from-bubonium-graveolens-essential-oil-by-hplc-and-absolute-configuration-determination-by-vcd
#15
Mohammed El-Amin Said, Isabelle Bombarda, Jean-Valère Naubron, Pierre Vanloot, Marion Jean, Abdelkrim Cheriti, Nathalie Dupuy, Christian Roussel
The chirality issues in the essential oils (EOs) of leaves and flowers from Bubonium graveolens were addressed by chiral high-performance liquid chromatography (HPLC) with polarimetric detection and vibrational circular dichroism (VCD). The chemical compositions of the crude oils of three samples were established by gas chromatography / mass spectrometry (GC/MS). The well-known cis-chrysanthenyl acetate (1), oxocyclonerolidol (2), and the recently disclosed cis-acetyloxychrysanthenyl acetate (3), the three major chiral compounds, were isolated by preparative HPLC...
December 26, 2016: Chirality
https://www.readbyqxmd.com/read/28013359/comparison-of-engraftment-following-different-stem-cell-mobilization-modalities-in-patients-with-multiple-myeloma-treated-with-a-uniform-induction-regimen-containing-bortezomib-cyclophosphamide-and-dexamethasone
#16
COMPARATIVE STUDY
Noam Benyamini, Irit Avivi, Eldad J Dann, Tsila Zuckerman, Noa Lavi, Tami Katz
Bortezomib-based induction followed by autologous stem cell transplantation is a common treatment for multiple myeloma (MM). Stem cell (SC) mobilization with granulocyte-colony stimulating factor (G-CSF) alone has become an alternative to G-CSF combined with chemotherapeutic agents. This study aimed to compare the efficacy of the two mobilization modalities following induction with a uniform regimen containing bortezomib, cyclophosphamide and dexamethasone (VCD). We retrospectively evaluated results of SC mobilization using either G-CSF alone or combined with high-dose cyclophosphamide (HD-CY) in MM patients after VCD induction...
March 2017: Annals of Hematology
https://www.readbyqxmd.com/read/27995257/supramolecular-organization-of-perfluorinated-1h-indazoles-in-the-solid-state-using-x-ray-crystallography-ssnmr-and-sensitive-vcd-and-non-sensitive-mir-fir-and-raman-to-chirality-vibrational-spectroscopies
#17
María M Quesada-Moreno, Juan Ramón Avilés-Moreno, Juan Jesús López-González, Kane Jacob, Laure Vendier, Michel Etienne, Ibon Alkorta, José Elguero, Rosa M Claramunt
1H-Indazole derivatives exhibit a remarkable property since some of them form chiral supramolecular structures starting from achiral monomers. The present work deals with the study of three perfluorinated 1H-indazoles that resolve spontaneously as conglomerates. These conglomerates can contain either a pure enantiomer (one helix) or a mixture of both enantiomers (both helices) with an enantiomeric excess (e.e.) of one of them. The difficulty of the structural analysis of these types of compounds is thus clear...
January 4, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27973824/unusual-chiroptical-properties-of-the-cryptophane-222-skeleton
#18
Delphine Pitrat, Nicolas Daugey, Marion Jean, Nicolas Vanthuyne, Frank Wien, Laurent Ducasse, Nathalie Calin, Thierry Buffeteau, Thierry Brotin
Enantiopure cryptophane-222 derivative (1) devoid of substituents was obtained via high-performance liquid chromatography (HPLC) using chiral stationary phases. The chiroptical properties of 1 were determined from polarimetry, electronic circular dichroism (ECD), synchrotron radiation circular dichroism (SRCD), vibrational circular dichroism (VCD), and Raman optical activity (ROA) experiments and were compared to those of the cryptophane-A (2) derivative. Unusual polarimetric results were obtained for 1 in CHCl3 solvent as the sign of the optical rotation (OR) values changes in the nonresonance region above 365 nm, whereas no change was observed in the CH2Cl2 solvent...
December 15, 2016: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/27973781/vibrational-optical-activity-of-bodipy-dimers-the-role-of-magnetic-electric-coupling-in-vibrational-excitons
#19
Sergio Abbate, Torsten Bruhn, Gennaro Pescitelli, Giovanna Longhi
The vibrational exciton (VE) interpretation of intense bisignated couplets in vibrational circular dichroism (VCD) spectra of a pair of atropisomeric BODIPY (boron dipyrrin) dimers is discussed. The role of intrinsic magnetic moments is crucial to reproduce the different behaviors of quasi-isomeric BODIPY dimers with different aryl junction.
December 29, 2016: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/27960581/distribution-of-ocular-component-measures-and-refraction-in-brazilian-school-children
#20
Rodrigo Pessoa Cavalcanti Lira, Carlos Eduardo Leite Arieta, Thaís Helena Moreira Passos, Diana Maziero, Gustavo Lima do Valle Astur, Ítalo Fernandes do Espírito Santo, Ana Cláudia Bertolani, Luis Fernando Pozzi, Rosane Silvestre de Castro, Álvaro Antônio Bandeira Ferraz
PURPOSE: To describe ocular component values and refraction in 6-17-year-old school children in Campinas, Brazil. METHODS: To obtain a representative sample, a total of 1100 6-17-year-old public school students in Campinas, Brazil, were randomly selected and divided into groups according to median ages 6 years (range 5-7 years), 10 years (range 9-11 years), 14 years (range 13-15 years), and 17 years (range 16-18 years). Cycloplegic autorefraction and ocular biometry were performed on each child...
February 2017: Ophthalmic Epidemiology
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