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OALib Journal期刊

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PERIOPERATIVE ANAPHYLAXIS – OUR EXPERIENCE OF TWO CASES
Nikhil Mudgalkar,Nagpadma,Sharley
National Journal of Medical Research , 2012,
Abstract: Anaphylactic reactions during intraoperative period are difficult to diagnose because of the anaesthetized state of the patient. During the perioperative period, any event relating to sudden-onset haemodynamic collapse or increased airway pressures during certain surgical procedures should raise suspicion of anaphylaxis. Though cited as rare in the western world, echinococcus infection is common in India, resulting in an increased ratio of cases, as and when compared to the western world. We report of two cases of perioperative anaphylaxis for hydatid disease surgery during 3 years period. Anaphylaxis is a medical emergency requiring prompt intervention. Although protocols vary in some of the details of management, adrenaline is the mainstay of treatment and early administration saves lives. However, even with prompt appropriate treatment, anaphylaxis can still kill, as our first case reports. From our experience, we suggest use of 100 % oxygen during the intraoperative period and maintaining anaesthesia with intravenous agents so that in case of an untoward catastrophic event, cerebral hypoxia may be delayed Increased reports of successfully managed cases will help in future references and in formulating guidelines of management [National J of Med Res 2012; 2(1.000): 93-95]
Established DFT methods lose sigma/pi separation in double bonds having hyperconjugative interactions
John N. Sharley
Physics , 2015,
Abstract: Accurate treatment of amide resonance is important in electronic structure calculation of protein, for Resonance Assisted Hydrogen Bonding in hydrogen bonded chains of backbone amides in protein secondary structure types such as beta sheet and alpha helix is determined by amide resonance. Variation in amide resonance is the means by which the hydrogen bonding in these chains is cooperative. Amide carbonyl orbitals are revealed by Natural Bond Orbital analysis to substantially maintain sigma/pi separation in the presence of non-amide plane hyperconjugative interactions with wavefunction methods but not with established DFT methods. This DFT error is most pronounced with small basis sets such as are used with DFT for proteins to reduce the basis function count. This error disturbs calculation of a range of amide donor/acceptor and steric interactions. This finding has important implications for the selection of electronic structure methods and basis sets for protein calculations. For example, great caution is needed in interpreting the results of applying established DFT methods to proteins containing beta sheet. We recommend that every protein DFT calculation of be accompanied by NBO assessment of maintenance of amide carbonyl sigma/pi separation and absence of carbonyl bond bending. Further, we propose that these metrics be standard benchmarks of electronic structure methods and basis sets.
Variation of protein backbone amide resonance by electrostatic field
John N. Sharley
Physics , 2015,
Abstract: Amide resonance is found to be sensitive to electrostatic field with component parallel or antiparallel the amide C-N bond. This effect is linear and without threshold in the biologically plausible electrostatic field range -0.005 to 0.005 au. Variation of amide resonance varies Resonance Assisted Hydrogen Bonding such as occurs in the hydrogen bonded chains of backbone amides of protein secondary structures such as beta sheet and non-polyproline helix such as alpha helix, varying the stability of the secondary structure. The electrostatic properties including permittivity of amino acid residue sidegroups influence the electrostatic field component parallel or antiparallel the C-N bond of each amide. The significance of this factor relative to other factors in protein folding depends on the magnitude of electrostatic field component parallel or antiparallel the C-N bond of each amide, and preliminary protein-scale calculations of the magnitude of these components suggest this factor warrants investigation in any analysis of stable protein structure or protein folding pathway. This factor is somewhat partnered with hydrophobia, since hydrophobia creates low permittivity environments. This factor is more directionally and hence structurally specific than hydrophobia.
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