Read by QxMD icon Read

Shields cl

Jan Macháček, Michael Bühl, Jindřich Fanfrlík, Drahomír Hnyk
11 B NMR chemical shifts of tricoordinated BX3 and tetracoordinated BX4 - compounds (X = H, CH3 , F, Cl, Br, I, OH, SH, NH2 , and CH═CH2 ) were computed, and the shielding tensors were explored not only within the nonrelativistic GIAO approach but also by application of both relativistic ZORA computations including spin-orbit coupling as well as scalar nonrelativistic ZORA computations (BP86 level of density functional theory). The contributions of the spin-orbit coupling to the overall shieldings are decisive for X = Br and I in both series...
December 21, 2017: Journal of Physical Chemistry. A
Janet E Del Bene, Ibon Alkorta, José Elguero
MP2/aug'-cc-pVTZ calculations have been carried out to investigate the halogen-bonded complexes formed when CO and CS act as electron-pair donors through C to ClF, ClNC, ClCl, ClOH, ClCN, ClCCH, and ClNH₂. CO forms only complexes stabilized by traditional halogen bonds, and all ClY molecules form traditional halogen-bonded complexes with SC, except ClF which forms only an ion-pair complex. Ion-pair complexes are also found on the SC:ClNC and SC:ClCl surfaces. SC:ClY complexes stabilized by traditional halogen bonds have greater binding energies than the corresponding OC:ClY complexes...
November 12, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Sudeep Das, Katja Haedicke, Jan Grimm
A big challenge for the clinical utilization of Cerenkov luminescence (CL) imaging is its low signal intensity, which is several orders of magnitude below ambient light. Consequently, highly sensitive cameras, sufficient shielding from background light and long acquisition times are required. To alleviate this problem, we hypothesize a strategy to convert the weak CL signal into a stronger fluorescence signal by using CL-activated formation of nitrenes from azides to locally fix a fluorescent probe in tissue by the formation of a covalent bond...
September 14, 2017: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
Su Chen, Ekaterina I Izgorodina
Nuclear magnetic resonance (NMR) has been widely used to elucidate the bulk structure of ionic liquids. In this work, we calculated (1)H NMR chemical shifts of 1-ethyl-3-methylimidazolium (C2mim(+)) ionic liquids combined with various anions such as chloride (Cl), tetrafluoroborate (BF4), hexafluorophosphate (PF6), acetate (OAc), trifluoroacetate (TFA), and dicyanamide (DCA). The previously established level of theory, HF/6-311G+(3df,2p), was used for the accurate prediction of NMR chemical shifts both in gas phase and in solvents with varying dielectric constant such as CHCl3 and ethanol...
June 26, 2017: Physical Chemistry Chemical Physics: PCCP
Arti Maheshwari, Harish Saraswat, Santosh Kumar Upadhyay
A major challenge in pharmaceuticals for clinical applications is to alter the solubility, stability, and toxicity of drug molecules in living systems. Cyclodextrins (CDs) have the ability to form host-guest inclusion complexes with pharmaceuticals for further development of new drug formulations. The inclusion complex of clomiphene citrate (CL), a poorly water-soluble drug, with native β-cyclodextrin (β-CD) was characterized by a one and two-dimensional nuclear magnetic resonance (NMR) spectroscopic approach and also by molecular docking techniques...
August 2017: Chirality
Abril C Castro, Marcel Swart, Célia Fonseca Guerra
In the present study, we have theoretically analyzed supramolecular complexes based on the Watson-Crick A-T and A-U base pairs using dispersion-corrected density functional theory (DFT). Hydrogen atoms H8 and/or H6 in the natural adenine and thymine/uracil bases were replaced, respectively, by substituents X8, Y6 = NH(-), NH2, NH3(+) (N series), O(-), OH, OH2(+) (O series), F, Cl or Br (halogen series). We examined the effect of the substituents on the hydrogen-bond lengths, strength and bonding mechanism, and the NMR shielding constants of the C2-adenine and C2-thymine/uracil atoms in the base pairs...
May 31, 2017: Physical Chemistry Chemical Physics: PCCP
Mario Bakardjiev, Aleš Růžička, Zdeňka Růžičková, Josef Holub, Oleg L Tok, Bohumil Štíbr
Initial studies on electrophilic halogenation of the dicarbaborane closo-1,2-C2B8H10 (1) have been carried out to reveal that the substitution takes place at B7 and B10 vertexes, which are the most removed from the CH positions. The course of the halogenation is strongly dependent on the nature of the halogenation agent and reaction conditions. Individual reactions led to the isolation of the monosubstituted compounds 1,2-C2B8H9-10-X (2) (where X = F, I) and 1,2-C2B8H9-7-X (3) (where X = Cl, I). Disubstituted carboranes 1,2-C2B8H8-7,10-X2 (4) (where X = Cl, Br, I) were obtained under more forcing conditions...
May 3, 2017: Inorganic Chemistry
L Jonas L Häller, Elena Mas-Marzá, Mateusz K Cybulski, Rajashekharayya A Sanguramath, Stuart A Macgregor, Mary F Mahon, Christophe Raynaud, Christopher A Russell, Michael K Whittlesey
Relativistic density functional theory calculations, both with and without the effects of spin-orbit coupling, have been employed to model hydride NMR chemical shifts for a series of [Ru(NHC)4(L)H](0/+) species (NHC = N-heterocyclic carbene; L = vacant, H2, N2, CO, MeCN, O2, P4, SO2, H(-), F(-) and Cl(-)), as well as selected phosphine analogues [Ru(R2PCH2CH2PR2)2(L)H](+) (R = (i)Pr, Cy; L = vacant, O2). Inclusion of spin-orbit coupling provides good agreement with the experimental data. For the NHC systems large variations in hydride chemical shift are shown to arise from the paramagnetic term, with high net shielding (L = vacant, Cl(-), F(-)) being reinforced by the contribution from spin-orbit coupling...
February 28, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
M Benedetti, F De Castro, F P Fanizzi
An inverse linear relationship between (73)Ge, (119)Sn and (207)Pb NMR chemical shifts and the overall sum of ionic radii of coordinated halido ligands has been discovered in tetrahedral [MXnY4-n] (M = Ge, Sn, Pb; 1 ≤ n ≤ 4; X, Y = Cl, Br, I) coordination compounds. This finding is consistent with a previously reported correlation found in octahedral, pentacoordinate and square planar platinum complexes. The effect of the coordinated halido ligands acting on the metal as shielding conducting rings is therefore confirmed also by (73)Ge, (119)Sn and (207)Pb NMR spectroscopy...
February 9, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Marcus Zuber, Michael Laaß, Elias Hamann, Sophie Kretschmer, Norbert Hauschke, Thomas van de Kamp, Tilo Baumbach, Thomas Koenig
Non-destructive imaging techniques can be extremely useful tools for the investigation and the assessment of palaeontological objects, as mechanical preparation of rare and valuable fossils is precluded in most cases. However, palaeontologists are often faced with the problem of choosing a method among a wide range of available techniques. In this case study, we employ x-ray computed tomography (CT) and computed laminography (CL) to study the first fossil xiphosuran from the Muschelkalk (Middle Triassic) of the Netherlands...
January 27, 2017: Scientific Reports
Michelle Lewis, Casey L Peiris, Nora Shields
QUESTION: Do long-term (> 3 months) home or community-based exercise programs improve function, reduce falls and prevent hospital readmissions in older people with cognitive impairment? DESIGN: Systematic review and meta-analysis of randomised, controlled trials. Electronic databases (CINAHL, PubMed, Medline, Embase, AMED) were searched from the earliest date possible until March 2016. PARTICIPANTS: Older adults (≥ 65 years) with cognitive impairment living in the community...
January 2017: Journal of Physiotherapy
Marcin Broniatowski, Monika Urbaś
Anionic phospholipids cardiolipins (CL) and phosphatidylglycerols (PG) dominate in the biomembranes of the majority of soil bacteria. CL to PG ratio differs between the species and is also dependent on the external conditions. CL/PG ratio is different in polluted than in unspoiled soils and it was hypothesized that it is connected with the activity of the membranelytic enzymes from the phospholipase A2 class (PLA2) as it was proved that persistent soil pollutants can activate PLA2. In our studies we applied the Langmuir monolayer technique and Brewster angle microscopy to elucidate the mechanism of the interactions of PLA2 with the model membranes formed by anionic phospholipids...
February 2017: Biochimica et Biophysica Acta
Ibon Alkorta, Jose Elguero, Janet E Del Bene
MP2/aug'-cc-pVTZ calculations have been carried out to investigate boron as an electron-pair donor in halogen-bonded complexes H(CO)2B:ClX and H(N2)2B:ClX, for X = F, Cl, OH, NC, CN, CCH, CH3, and H.Equilibrium halogen-bonded complexes with boron the electron-pair donor have been found on all of the potential surfaces except for H(CO)2B:ClCH3 and H(N2)2B:ClF.The majority of these complexes are stabilized by traditional halogen bonds, except for H(CO)2B:ClF, H(CO)2B:ClCl, H(N2)2B:ClCl, and H(N2)2B:ClOH which are stabilized by chlorine-shared halogen bonds...
July 14, 2016: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Roman Savka, Marvin Bergmann, Yuki Kanai, Sabine Foro, Herbert Plenio
Based on 1-amino-4-hydroxy-triptycene, new saturated and unsaturated triptycene-NHC (N-heterocyclic carbene) ligands were synthesized from glyoxal-derived diimines. The respective carbenes were converted into metal complexes [(NHC)MX] (M=Cu, Ag, Au; X=Cl, Br) and [(NHC)MCl(cod)] (M=Rh, Ir; cod=1,5-cyclooctadiene) in good yields. The new azolium salts and metal complexes suffer from limited solubility in common organic solvents. Consequently, the introduction of solubilizing groups (such as 2-ethylhexyl or 1-hexyl by O-alkylation) is essential to render the complexes soluble...
July 4, 2016: Chemistry: a European Journal
Shahbaz Ahmed, Derek Brown, Saad B S Ahmed, Muhammad B Kakakhel, Wazir Muhammad, Amjad Hussain
A revised translating bed total body irradiation (TBI) technique is developed for shielding organs at risk (lungs) to tolerance dose limits, and optimizing dose distribution in three dimensions (3D) using an asymmetrically-adjusted, dynamic multileaf collimator. We present a dosimetric comparison of this technique with a previously developed symmetric MLC-based TBI technique. An anthropomor-phic RANDO phantom is CT scanned with 3 mm slice thickness. Radiological depths (RD) are calculated on individual CT slices along the divergent ray lines...
March 8, 2016: Journal of Applied Clinical Medical Physics
Arman Mashayekhi, Murat Hasanreisoglu, Carol L Shields, Jerry A Shields
PURPOSE: To determine the efficacy and safety of external beam radiation for treatment of choroidal lymphoma (CL). DESIGN: Retrospective case series. PARTICIPANTS: Twenty-five eyes of 24 patients with CL treated with external beam radiation. METHOD: Review of medical records. MAIN OUTCOME MEASURES: Tumor control, visual acuity, and radiation complications. RESULTS: The mean age of the patients was 62 years (median, 65; range, 32-89 years)...
October 2016: Retina
Amy M Dennett, Casey L Peiris, Nora Shields, Luke A Prendergast, Nicholas F Taylor
QUESTION: Is there a dose-response effect of exercise on inflammation, fatigue and activity in cancer survivors? DESIGN: Systematic review with meta-regression analysis of randomised trials. PARTICIPANTS: Adults diagnosed with cancer, regardless of specific diagnosis or treatment. INTERVENTION: Exercise interventions including aerobic and/or resistance as a key component. OUTCOME MEASURES: The primary outcome measures were markers of inflammation (including C-reactive protein and interleukins) and various measures of fatigue...
April 2016: Journal of Physiotherapy
Irina V Mirzaeva, Dmitry A Mainichev, Svetlana G Kozlova
(103)Rh NMR parameters and the bonding structure of three complexes of [Cp*RhX2]2, where X = Cl, Br, or I, have been studied with the help of natural bond orbitals (NBOs) and natural localized molecular orbitals (NLMOs). The complexes of [Cp*RhX2]2, where X = Cl, Br, or I, have similar bonding structures, with the major difference being in the degree of covalency of the Rh-X bonds. The decomposition of (103)Rh NMR shielding into diamagnetic, paramagnetic, and spin-orbit terms shows that normal halogen dependence (NHD) of the (103)Rh NMR shift is defined mostly by the paramagnetic term, with the spin-orbit term being significantly smaller...
March 24, 2016: Journal of Physical Chemistry. A
Dhilon S Patel, Suyong Re, Emilia L Wu, Yifei Qi, Phillip E Klebba, Göran Widmalm, Min Sun Yeom, Yuji Sugita, Wonpil Im
The asymmetric outer membrane of Gram-negative bacteria is formed of the inner leaflet with phospholipids and the outer leaflet with lipopolysaccharides (LPS). Outer membrane protein F (OmpF) is a trimeric porin responsible for the passive transport of small molecules across the outer membrane of Escherichia coli. Here, we report the impact of different levels of heterogeneity in LPS environments on the structure and dynamics of OmpF using all-atom molecular dynamics simulations. The simulations provide insight into the flexibility and dynamics of LPS components that are highly dependent on local environments, with lipid A being the most rigid and O-antigen being the most flexible...
February 23, 2016: Biophysical Journal
Kentaro Ifuku, Takumi Noguchi
Photosystem II (PSII), which catalyzes photosynthetic water oxidation, is composed of more than 20 subunits, including membrane-intrinsic and -extrinsic proteins. The PSII extrinsic proteins shield the catalytic Mn4CaO5 cluster from the outside bulk solution and enhance binding of inorganic cofactors, such as Ca(2+) and Cl(-), in the oxygen-evolving center (OEC) of PSII. Among PSII extrinsic proteins, PsbO is commonly found in all oxygenic organisms, while PsbP and PsbQ are specific to higher plants and green algae, and PsbU, PsbV, CyanoQ, and CyanoP exist in cyanobacteria...
2016: Frontiers in Plant Science
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"