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https://www.readbyqxmd.com/read/27897329/molecules-in-molecules-fragment-based-method-for-the-calculation-of-chiroptical-spectra-of-large-molecules-vibrational-circular-dichroism-and-raman-optical-activity-spectra-of-alanine-polypeptides
#1
K V Jovan Jose, Krishnan Raghavachari
The molecules-in-molecules (MIM) fragment-based method has recently been adapted to evaluate the chiroptical (vibrational circular dichroism [VCD] and Raman optical activity [ROA]) spectra of large molecules such as peptides. In the MIM-VCD and MIM-ROA methods, the relevant higher energy derivatives of the parent molecule are assembled from the corresponding derivatives of smaller fragment subsystems. In addition, the missing long-range interfragment interactions are accounted at a computationally less expensive level of theory (MIM2)...
December 2016: Chirality
https://www.readbyqxmd.com/read/27892789/4-vinylcyclohexene-diepoxide-disrupts-sperm-characteristics-endocrine-balance-and-redox-status-in-testes-and-epididymis-of-rats
#2
Isaac A Adedara, Amos O Abolaji, Emmanuel O Ladipo, Ore J Fatunmibi, Ayodeji O Abajingin, Ebenezer O Farombi
OBJECTIVES: Exposure to 4-vinylcyclohexene diepoxide (VCD) was reported to induce testicular germ cell toxicity in rodents. However, there is paucity of information on the precise biochemical and molecular mechanisms of VCD-induced male reproductive toxicity. METHODOLOGY: This study investigated the influence of VCD on testicular and epidydimal functions following oral exposure of Wistar rats to VCD at 0, 100, 250 and 500 mg/kg for 28 consecutive days. RESULTS: Administration of VCD significantly decreased the body weight gain and organo-somatic indices of the testes and epididymis...
November 28, 2016: Redox Report: Communications in Free Radical Research
https://www.readbyqxmd.com/read/27869352/configurationally-stable-chiral-dithia-bridged-hetero-4-helicene-radical-cation-electronic-structure-and-absolute-configuration
#3
Milan Kivala, Bettina D Gliemann, Ana G Petrovic, Eva M Zolnhofer, Pavlo O Dral, Frank Hampel, Georg Breitenbruch, Schulze Philipp, Vijay Raghavan, Karsten Meyer, Prasad L Polavarapu, Nina Berova
A stable chiral hetero[4]helicene radical cation was synthesized and characterized by UV-Vis absorption and EPR spectroscopy as well as X-ray crystallography. For the first time a combination of chiroptical methods involving ECD, ORD, and VCD, supported by quantum mechanical predictions, enabled the elucidation of the absolute configuration of such open-shell helical species.
November 21, 2016: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/27832985/effects-of-raloxifene-against-letrozole-induced-bone-loss-in-chemically-induced-model-of-menopause-in-mice
#4
Abul Kalam, Sushama Talegaonkar, Divya Vohora
INTRODUCTION: The deleterious effects of letrozole, an aromatase inhibitor, used in the adjuvant treatment of breast cancer in postmenopausal women, on bone are well-documented and represent a major drawback to its clinical use. Raloxifene, a selective estrogen receptor modulator and a clinically approved anti-osteoporotic drug, has been recently demonstrated to be efficacious in women with breast cancer. The present study evaluated the effects of preventive and curative treatment with raloxifene on letrozole-induced alterations of bone microarchitecture and turnover markers in a chemically-induced menopause model in mice...
November 8, 2016: Molecular and Cellular Endocrinology
https://www.readbyqxmd.com/read/27830854/atropisomerism-in-3-arylthiazolidine-2-thiones-a-combined-dynamic-nmr-and-dynamic-hplc-study
#5
A Ciogli, S Vivek Kumar, M Mancinelli, A Mazzanti, S Perumal, C Severi, C Villani
Sterically hindered 3-arylthiazolidine-2-thiones were prepared by a solvent-free reaction with arylisothiocyanates and 1,4-dithiane-2,5-diol. Atropisomerism was observed in two compounds (3 and 4, aryl = 1-naphthyl and 2-methylnaphth-1-yl), whose rotational energy barriers were measured using dynamic NMR and dynamic HPLC. The experimental analyses were supported by DFT calculations. Thermally stable atropisomers were obtained by dehydration of compounds 3 and 4 and the absolute configuration of the atropisomers of compound 6 was determined by theoretical simulation of the ECD and VCD spectra...
November 10, 2016: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/27805191/vibrational-spectroscopy-as-a-direct-stereochemical-probe-for-polyhydroxylated-molecules
#6
F Passareli, A N L Batista, A J Cavalheiro, W A Herrebout, J M Batista Junior
A simple IR and VCD spectra-structure relationship is proposed for the determination of the relative and absolute configurations of polyhydroxylated molecules using a series of styryl-pyrones as model compounds. Spectral signatures identified for free molecules and acetonide derivatives may be used for stereochemical assignments of related molecules without the aid of quantum-chemical calculations.
November 16, 2016: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27801585/absolute-configuration-determination-of-2-3-dihydro-1h-5h-pyrazolo-1-2-a-pyrazoles-using-chiroptical-methods-at-different-wavelengths
#7
Eva Pušavec Kirar, Uroš Grošelj, Amalija Golobič, Franc Požgan, Stefan Pusch, Carina Weber, Lars Andernach, Bogdan Štefane, Till Opatz, Jurij Svete
A correlation between the absolute configuration and chiroptical properties of non-racemic 1,6,7-trisubstituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazoles was studied. A series of 16 novel representatives were prepared by Cu-catalyzed [3+2]-cycloadditions of racemic (Z)-2-benzylidene-5-oxopyrazolidin-2-ium-1-ides to tert-butyl (S)-(3-oxopent-4-yn-2-yl)carbamate, and their structures were determined by NMR, VCD, ECD, and X-ray diffraction. A clear correlation between the sign of specific rotation and configuration at position C(1) allows for easy determination of the absolute configuration of 1,6,7-trisubstituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazoles by ECD and NMR...
November 1, 2016: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/27793768/cognitive-changes-across-the-menopause-transition-a-longitudinal-evaluation-of-the-impact-of-age-and-ovarian-status-on-spatial-memory
#8
Stephanie V Koebele, Sarah E Mennenga, Ryoko Hiroi, Alicia M Quihuis, Lauren T Hewitt, Mallori L Poisson, Christina George, Loretta P Mayer, Cheryl A Dyer, Leona S Aiken, Laurence M Demers, Catherine Carson, Heather A Bimonte-Nelson
Cognitive changes that occur during mid-life and beyond are linked to both aging and the menopause transition. Studies in women suggest that the age at menopause onset can impact cognitive status later in life; yet, little is known about memory changes that occur during the transitional period to the postmenopausal state. The 4-vinylcyclohexene diepoxide (VCD) model simulates transitional menopause in rodents by depleting the immature ovarian follicle reserve and allowing animals to retain their follicle-deplete ovarian tissue, resulting in a profile similar to the majority of perimenopausal women...
October 26, 2016: Hormones and Behavior
https://www.readbyqxmd.com/read/27779841/reinvestigation-of-the-absolute-configurations-of-chiral-%C3%A3-mercaptoalkanones-using-vibrational-circular-dichroism-and-1h-nmr-analysis
#9
Christiane Kiske, Svenja Noerenberg, Miriam Ecker, Xingyue Ma, Tohru Taniguchi, Kenji Monde, Wolfgang Eisenreich, Karl-Heinz Engel
The absolute configurations of chiral β-mercaptoalkanones had been previously assigned on the basis of the 1H NMR anisotropy method using (S)-2-methoxy-2-(1-naphthyl)propionic acid ((S)-MαNP) as chiral auxiliary. This study presents a reinvestigation of the configurations of 4-mercapto-2-pentanone, 1, 4-mercapto-2-heptanone, 2, and 2-mercapto-4-heptanone, 3. Enantiomers of 1, 2 and 3 were obtained by lipase-catalyzed hydrolyses of the respective acetylthioalkanones. Upon derivatization with (S)-MαNP, the configurations of the reaction products were deduced on the basis of the order of the HPLC-elution of the diastereoisomeric thioesters assuming that the sector rule previously developed for secondary alcohols is also valid for thiols...
October 25, 2016: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/27769945/akt-activation-by-evodiae-fructus-extract-protects-ovary-against-4-vinylcyclohexene-diepoxide-induced-ovotoxicity
#10
Eun-Young Nam, Sun Ah Kim, Heejung Kim, Su-Hyun Kim, Jae-Hyun Han, Ju-Hee Lee, Dong-Il Kim
ETHNOPHARMACOLOGICAL RELEVANCE: Evodiae Fructus (EF) is the dried, unripe fruit of Evodia rutaecarpa Benth., and one of the main components of traditional herbal prescriptions issued for the treatment of sterility caused by irregular menstruation in Korea. However, scientific evidence regarding the efficacy and action mechanism of EF is lacking. AIM OF THE STUDY: In this study, the authors established an in vitro screening tool to identify promising new drug candidates in herbal medicines for the prevention and treatment of premature ovarian failure...
October 18, 2016: Journal of Ethnopharmacology
https://www.readbyqxmd.com/read/27726359/absolute-configuration-of-menthene-derivatives-by-vibrational-circular-dichroism
#11
Julio C Pardo-Novoa, Héctor M Arreaga-González, Mario A Gómez-Hurtado, Gabriela Rodríguez-García, Carlos M Cerda-García-Rojas, Pedro Joseph-Nathan, Rosa E Del Río
The aerial parts of Ageratina glabrata afforded (-)-(3S,4R,5R,6S)-3,5,6-trihydroxy-1-menthene 3-O-β-d-glucopyranoside (1) and (-)-(3S,4S,6R)-3,6-dihydroxy-1-menthene 3-O-β-d-glucopyranoside (3). Acid hydrolysis of 1 yielded (+)-(1R,4S,5R,6R)-1,5,6-trihydroxy-2-menthene (5) and (+)-(1S,4S,5R,6R)-1,5,6-trihydroxy-2-menthene (6), while hydrolysis of 3 yielded (+)-(3S,4S,6R)-3,6-dihydroxy-1-menthene (10), (+)-(1R,4S,6R)-1,6-dihydroxy-2-menthene (11), and (+)-(1S,4S,6R)-1,6-dihydroxy-2-menthene (12). The structures of the new compounds 1, 2, 5-9, and 11 were defined by 1D and 2D NMR experiments, while the absolute configurations of the series of compounds were determined by comparison of the experimental vibrational circular dichroism (VCD) spectra of the 1,6-acetonide 5-acetate derived from 6 and of the 1,6-acetonide derived from 12 with their DFT-calculated spectra...
October 11, 2016: Journal of Natural Products
https://www.readbyqxmd.com/read/27723329/atropoisomerism-in-biflavones-the-absolute-configuration-of-agathisflavone-via-chiroptical-spectroscopy
#12
Cody L Covington, Fernando M S Junior, Jessica H S Silva, Ricardo M Kuster, Mauro B de Amorim, Prasad L Polavarapu
The first natural occurrence in optically active form of the dimeric flavonoid agathisflavone and definition of its axial chirality using chiroptical spectroscopic methods are described. The experimental electronic circular dichroism, electronic dissymmetry factor, optical rotatory dispersion, vibrational circular dichroism (VCD), and vibrational dissymmetry factor spectra of agathisflavone are presented and analyzed with their corresponding quantum chemical predictions to definitively assign the axial chirality of (-)-agathisflavone as (aS)...
October 10, 2016: Journal of Natural Products
https://www.readbyqxmd.com/read/27711524/chiral-recognition-by-fullerenes-chfclbr-enantiomers-in-the-c82-cage
#13
Helena Dodziuk, Kenneth Ruud, Tatiana Korona, Taye B Demissie
Density-functional theory and symmetry-adapted perturbation theory calculations on complexes of the enantiomers of CHFClBr with the most stable isomer of C82-3 fullerene show that despite the guests being too large for the host cage, they are nevertheless stabilized by electrostatic interactions. The complexation leads to considerable strain on the cage and the guests accompanied by compression of the bonds of the guest molecule, resulting in considerable complexation-induced changes in the infrared (IR), vibrational circular dichroism (VCD), nuclear magnetic resonance (NMR), and UV-vis spectra...
September 21, 2016: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27704812/an-effective-fully-polarizable-qm-mm-approach-to-model-vibrational-circular-dichroism-spectra-of-systems-in-aqueous-solutions
#14
Tommaso Giovannini, Marta Olszowka, Chiara Cappelli
We propose a methodology, based on the combination of classical Molecular Dynamics (MD) simulations with a fully polarizable Quantum Mechanical (QM)/Molecular Mechanics (MM)/Polarizable Continuum Model (PCM) Hamiltonian to calculate Vibrational Circular Dichroism (VCD) spectra of chiral systems in aqueous solution. Polarization effects are included in the MM force field by exploiting an approach based on Fluctuating Charges (FQ). By performing the MD, the description of the solvating environment is enriched by taking into account the dynamical aspects of the solute-solvent interactions...
October 5, 2016: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/27682594/long-term-outcome-after-application-of-the-angio-seal-vascular-closure-device-in-minipigs
#15
Lisa Kabelitz, Andrea Nonn, Kay W Nolte, Omid Nikoubashman, Ahmed Othman, Sarah Heringer, Martin Kramer, Martin Wiesmann, Marc A Brockmann
Minipigs are frequently used in (neuro-)interventional research. Longitudinal experiments may require repeated vessel access via the femoral artery. Anticoagulation and incompliance of the animals necessitates the use of a vascular closure device (VCD). The effects of the Angio-Seal VCD in minipigs were longitudinally assessed. Minipig (42±8.4 kg body weight) femoral arteries were sealed using the 8F (n = 6) or 6F (n = 7) Angio-Seal VCD. The pre-interventional femoral artery diameter was 5.1±0.4 mm (4.3-5...
2016: PloS One
https://www.readbyqxmd.com/read/27676128/three-dimensional-quantification-of-microarchitecture-and-vessel-regeneration-by-synchrotron-radiation-microcomputed-tomography-in-a-rat-model-of-spinal-cord-injury
#16
Yong Cao, Yuan Zhou, Shuangfei Ni, Tianding Wu, Ping Li, Shenghui Liao, Jianzhong Hu, Hongbin Lu
A full understanding of the mechanisms behind spinal cord injury (SCI) processes requires reliable three-dimensional (3D) imaging tools for a thorough analysis of changes in angiospatial architecture. We aimed to use synchrotron radiation μCT (SRμCT) to characterize 3D temporal-spatial changes in microvasculature post-SCI. Morphometrical measurements revealed a significant decrease in vascular volume fraction, vascular bifurcation density, vascular segment density, and vascular connectivity density 1 day post-injury, followed by a gradual increase at 3, 7, and 14 days...
December 2, 2016: Journal of Neurotrauma
https://www.readbyqxmd.com/read/27670248/discrimination-of-axial-and-central-stereogenic-elements-in-chiral-bis-oxazolines-based-on-atropisomeric-3-3-bithiophene-scaffolds-through-chiroptical-spectroscopies
#17
Sara Gabrieli, Giuseppe Mazzeo, Giovanna Longhi, Sergio Abbate, Tiziana Benincori
Two diastereoisomeric pairs of bis-oxazolines, provided with a stereogenic center at carbon 4 and based on the 3,3'-bithiophene atropisomeric scaffold, were synthesized and structurally characterized. They differ in the substituents at positions 2 and 5 of the thiophene rings, which are functionalized with methyl (1) or phenyl (2) groups, respectively. In vibrational circular dichroism (VCD) spectra, recorded in CCl4 solutions, it is possible to distinctly recognize the characteristic features of axial and central stereogenic elements...
October 2016: Chirality
https://www.readbyqxmd.com/read/27664415/abnormal-vocal-cord-movement-in-patients-with-and-without-airway-obstruction-and-asthma-symptoms
#18
Kathy Low, Laurence Ruane, Nizam Uddin, Paul Finlay, Kenneth K Lau, Kais Hamza, Peter W Holmes, Garun Hamilton, Philip G Bardin
BACKGROUND: Abnormal vocal cord movements can cause laryngeal extrathoracic airway obstruction (often called vocal cord dysfunction - VCD) leading to asthma-like symptoms. These aberrant movements are characteristically present during inspiration and termed paradoxical vocal cord movement (PVCM). We have reported PVCM in up to 40% of severe asthmatics but it is not known if PVCM is detectable in all patients with asthma-like symptoms and if the condition is more often associated with abnormal lung function...
September 24, 2016: Clinical and Experimental Allergy: Journal of the British Society for Allergy and Clinical Immunology
https://www.readbyqxmd.com/read/27647594/evidence-of-oxidative-damage-and-reproductive-dysfunction-accompanying-4-vinylcyclohexene-diepoxide-exposure-in-female-wistar-rats
#19
Amos O Abolaji, Isaac A Adedara, Ayodeji O Abajingin, Ore J Fatunmibi, Emmanuel O Ladipo, Ebenezer O Farombi
4-Vinylcyclohexene diepoxide (VCD) is an occupational chemical widely reported to deplete ovarian follicles in rodents. Here, we investigated VCD-induced reproductive dysfunction in female Wistar rats. The rats were orally administered with VCD (100, 250 and 500mg/kg) for twenty-eight days. Thereafter, we evaluated selected biomarkers of oxidative damage, inflammation, endocrine disruption, and apoptosis. We observed that VCD increased ovarian and uterine malondialdehyde (MDA) level, and catalase, glutathione peroxidase (GPx) and glutathione S-transferase (GST) activities in rats (p<0...
September 16, 2016: Reproductive Toxicology
https://www.readbyqxmd.com/read/27641942/starclose-se%C3%A2-hemostasis-after-6f-direct-antegrade-superficial-femoral-artery-access-distal-to-the-femoral-head-for-peripheral-endovascular-procedures-in-obese-patients
#20
Stavros Spiliopoulos, Panagiotis Kitrou, Nikolaos Christeas, Dimitris Karnabatidis
PURPOSE: Direct superficial femoral artery (SFA) antegrade puncture is a valid alternative to common femoral artery (CFA) access for peripheral vascular interventions. Data investigating vascular closure device (VCD) hemostasis of distant SFA 6F access are limited. We aimed to investigate the safety and effectiveness of the Starclose SE® VCD for hemostasis, following direct 6F antegrade SFA access distal to the femoral head. METHODS: This prospective, single-center study included patients who were not suitable for CFA puncture and were scheduled to undergo peripheral endovascular interventions using direct antegrade SFA 6F access, at least 2 cm below the inferior edge of femoral head...
November 2016: Diagnostic and Interventional Radiology: Official Journal of the Turkish Society of Radiology
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