Modification of the local self‐consistent field method for modeling surface reactivity of covalent solids

Gorb, Leonid; Rivail, Jean‐Louis; Théry, Vincent; Rinaldi, Daniel

doi:10.1002/(sici)1097-461x(1996)60:7<1525::aid-qua34>3.0.co;2-#

Cited by 6 publications

(1 citation statement)

References 44 publications

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“…The contribution due to exchange interaction between the electrons of the cluster and those of the remaining crystal appears in the total energy as a natural result of the assumptions made for the wave functions. When the INDO calculation scheme is used, our approach enables one to take into account complete exchange contribution in contrast to the work of Gorb et al 35, where only a part of it is present in the total energy.…”

Section: Resultsmentioning

confidence: 99%

Catheter treatment of critical aortic valve stenosis in the neonate: Choice of approach

Hijazi

2002

Cathet Cardio Intervent

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Critical aortic valve stenosis AS in the neonate is an uncommon form of congenital heart disease. Neonates with this condition often present in the immediate neonatal period in shock and very low cardiac output. When a neonate is diagnosed to have critical AS, the most important question raised is the size of the left ventricle (LV) and if the ventricle is adequate to sustain a biventricular state. Once the LV is deemed to be sufficient to support the systemic circulation, the decision in each center has to be focused on the best approach to relieve obstruction, mainly surgical versus catheter to open the critically narrowed valve. However, prior to this, neonates with this condition have to be stabilized, including the use of prostaglandin to main patency of the ductus, inotropic support, and maintenance of a normal acid-base balance. The decision to proceed is institution-dependent. However, in the presence of good interventional team, it is advisable to proceed with catheter intervention and keep the use of surgery as a backup option. Neonates with critical AS should be mechanically ventilated; this facilitates the performance of the intended procedure and optimizes their acid-base equilibrium. In the catheterization laboratory, one important decision to make is the approach to dilate the aortic valve.Currently, there are four different techniques to cross the valve and perform the valvuloplasty. One, the standard retrograde femoral arterial route. Most cardiologists are familiar with and use this approach due to its ease. Potential complications resulting from this technique include damage to the femoral artery used, perforation of one of the valve cusps, and the inability to cross the valve. Two, retrograde via carotid artery cutdown. This technique is being used more commonly. The cutdown is usually performed by a cardiac or a pediatric surgeon using magnifying glasses. The valve is crossed relatively easily using a Judkins right coronary catheter. The vessel can be repaired easily after the procedure. Potential complications include the loss of the carotid artery and potential perforation of the valve cusp. The major advantages using this technique is the obvious preservation of the femoral artery and the procedure can be done at the bed side under transesophageal echocardiographic guidance. Three, anterograde via femoral vein. The main advantages of this technique are the preservation of the femoral artery and potentially less chance of cusp perforation. Four, anterograde via umbilical vein. Obviously, this technique has even more advantages of femoral vessel vein/artery preservation and again less chance of cusp perforation. Both anterograde techniques are more challenging and potentially may require longer fluoroscopy and procedure time.In this issue, Peuster et al. describe their experience using the anterograde technique in 17 neonates with critical AS. The procedure was possible in all 17 neonates. Four neonates underwent the procedure via the umbilical vein and the remaining 13 via the femoral vein....

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Section: Resultsmentioning

confidence: 99%

Catheter treatment of critical aortic valve stenosis in the neonate: Choice of approach

Hijazi

2002

Cathet Cardio Intervent

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Improved embedded molecular cluster model

Shidlovskaya

2002

Int J of Quantum Chemistry

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ABSTRACT:We demonstrate that boundary effects (i.e., displacements of the cluster boundary atoms from their lattice sites and the difference between effective charges of the perfect crystal atoms and those of the cluster atoms in the case of a cluster with no point defect in it) in an embedded molecular cluster (EMC) model can be radically reduced. A new embedding scheme is proposed. It includes search for the structural elements (SE) of which perfect crystal is composed, use of corresponding to these SE expression for the total energy, and application of the degree of localization of equations consistent with the wave functions of the cluster. To get equations for the cluster wave functions, the problem of varied subsystem in the field of the frozen remaining part of the whole electron system" is investigated in the framework of a oneelectron approximation. The consideration is general for every task of this type. Homogeneous equations resulting directly from variation of the total energy expression are obtained and transformed to the eigenvalue problem equations. Orthogonality constraints are not imposed during variation. A particular case of the equations describing mutually orthogonal one-electron wave functions of the cluster staying nonorthogonal to those of the remaining crystal is found. A proposed embedding scheme is realized in the CLUSTER code based on the calculation scheme of the semiempirical INDO method. Boundary effects both in the standard (cluster in the field of the infinite lattice of nonpoint spherical charges) and new embedding scheme are investigated, calculating the clusters of LiF, MgO, NaCl, KCl, and AgCl crystals. Significant reduction of the boundary effects in the new embedding scheme is achieved. Reasons for the boundary effects are discussed.

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A Quest for Efficient Methods of Disintegration of Organophosphorus Compounds: Modeling Adsorption and Decomposition Processes

Michalkova

Gorb

Leszczyński

2007

Challenges and Advances in Computational Chemistry and Physics

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Modification of the local self‐consistent field method for modeling surface reactivity of covalent solids

Cited by 6 publications

References 44 publications

Catheter treatment of critical aortic valve stenosis in the neonate: Choice of approach

Catheter treatment of critical aortic valve stenosis in the neonate: Choice of approach

Improved embedded molecular cluster model

A Quest for Efficient Methods of Disintegration of Organophosphorus Compounds: Modeling Adsorption and Decomposition Processes

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