Extrinsic compression of left main coronary artery due to pulmonary artery aneurysm and pulmonary hypertension.

Idiopathic pulmonary arterial hypertension is a serious condition that carries a poor prognosis. While exertional dyspnea is the most common symptom, angina like chest pain, most often due to right ventricle ischemia, may occur at advanced stages. We present a patient with pulmonary hypertension symptomatic for dyspnea and angina in whom computed coronary tomography angiography showed compression of the left main coronary artery by a large pulmonary artery aneurysm. Percutaneous coronary intervention and stenting was performed resulting in significant clinical improvement. This case emphasizes the role of different cardiovascular imaging modalities for the diagnosis of rare conditions.

Tratamiento hibrido de divertículo de Kommerell complicado / Hybrid treatment of complicated Kommerell's diverticulum

Se describe un caso clínico en el que se aplica una técnica hibrida para el tratamiento del Divertículo de Kommerell complicado por ser una estrategia segura para nuestra paciente. La decisión debe basarse en el conocimiento de la anatomía compleja, el inicio y extensión de la disección como el estado clínico del paciente.

A clinical case is described in which a hybrid technique is applied for the treatment of Kommerell's Diverticulum, complicated by being a safe strategy for our patient. The decision should be based on knowledge of the complex anatomy, the initiation and extent of the dissection as well as the clinical status of the patient.

Matrix-free application of Hamiltonian operators in Coifman wavelet bases.

A means of evaluating the action of Hamiltonian operators on functions expanded in orthogonal compact support wavelet bases is developed, avoiding the direct construction and storage of operator matrices that complicate extension to coupled multidimensional quantum applications. Application of a potential energy operator is accomplished by simple multiplication of the two sets of expansion coefficients without any convolution. The errors of this coefficient product approximation are quantified and lead to use of particular generalized coiflet bases, derived here, that maximize the number of moment conditions satisfied by the scaling function. This is at the expense of the number of vanishing moments of the wavelet function (approximation order), which appears to be a disadvantage but is shown surmountable. In particular, application of the kinetic energy operator, which is accomplished through the use of one-dimensional (1D) [or at most two-dimensional (2D)] differentiation filters, then degrades in accuracy if the standard choice is made. However, it is determined that use of high-order finite-difference filters yields strongly reduced absolute errors. Eigensolvers that ordinarily use only matrix-vector multiplications, such as the Lanczos algorithm, can then be used with this more efficient procedure. Applications are made to anharmonic vibrational problems: a 1D Morse oscillator, a 2D model of proton transfer, and three-dimensional vibrations of nitrosyl chloride on a global potential energy surface.

Plasmonic enhancement of Raman optical activity in molecules near metal nanoshells.

Surface-enhanced Raman optical activity (SEROA) is investigated theoretically for molecules near a metal nanoshell. For this purpose, induced molecular electric dipole, magnetic dipole, and electric quadrupole moments must all be included. The incident field and the induced multipole fields all scatter from the nanoshell, and the scattered waves can be calculated via extended Mie theory. It is straightforward in this framework to calculate the incident frequency dependence of SEROA intensities, i.e., SEROA excitation profiles. The differential Raman scattering is examined in detail for a simple chiroptical model that provides analytical forms for the relevant dynamical molecular response tensors. This allows a detailed investigation into circumstances that simultaneously provide strong enhancement of differential intensities and remain selective for molecules with chirality.

Quantum and electromagnetic propagation with the conjugate symmetric Lanczos method.

The conjugate symmetric Lanczos (CSL) method is introduced for the solution of the time-dependent Schrodinger equation. This remarkably simple and efficient time-domain algorithm is a low-order polynomial expansion of the quantum propagator for time-independent Hamiltonians and derives from the time-reversal symmetry of the Schrodinger equation. The CSL algorithm gives forward solutions by simply complex conjugating backward polynomial expansion coefficients. Interestingly, the expansion coefficients are the same for each uniform time step, a fact that is only spoiled by basis incompleteness and finite precision. This is true for the Krylov basis and, with further investigation, is also found to be true for the Lanczos basis, important for efficient orthogonal projection-based algorithms. The CSL method errors roughly track those of the short iterative Lanczos method while requiring fewer matrix-vector products than the Chebyshev method. With the CSL method, only a few vectors need to be stored at a time, there is no need to estimate the Hamiltonian spectral range, and only matrix-vector and vector-vector products are required. Applications using localized wavelet bases are made to harmonic oscillator and anharmonic Morse oscillator systems as well as electrodynamic pulse propagation using the Hamiltonian form of Maxwell's equations. For gold with a Drude dielectric function, the latter is non-Hermitian, requiring consideration of corrections to the CSL algorithm.

Multimode wavelet basis calculations via the molecular self-consistent-field plus configuration-interaction method.

Wavelets provide potentially useful quantum bases for coupled anharmonic vibrational modes in polyatomic molecules as well as many other problems. A single compact support wavelet family provides a flexible basis with properties of orthogonality, localization, customizable resolution, and systematic improvability for general types of one-dimensional and separable systems. While direct product wavelet bases can be used in coupled multidimensional problems, exponential scaling of basis size with dimensionality ultimately provides limits on the number of coupled modes that can be treated simultaneously in exact quantum calculations. The molecular self-consistent-field plus configuration-interaction method is used here in multimode wavelet calculations to reduce the basis size without sacrificing flexibility or the ability to systematically control errors. Both two-dimensional Cartesian coordinate and three-dimensional curvilinear coordinate systems are examined with wavelets serving as universal bases in each case. The first example uses standard Daubechies [Ten Lectures on Wavelets (SIAM, Philadelphia (1992)] wavelets for each mode and the second adapts symmlet wavelets to intervals for each of the curvilinear coordinates.

Additions to the class of symmetric-antisymmetric multiwavelets: derivation and use as quantum basis functions.

Multiwavelet bases have been shown recently to apply to a variety of quantum problems. There are, however, only a few multiwavelet families that have been defined to date. Chui-Lian-type symmetric and antisymmetric multiwavelets are derived here that equal and exceed the polynomial interpolating power of previously available examples. Adaptations to domain edges are made with a view to use in curvilinear coordinate molecular calculations. The new highest-order multiwavelet family is shown to provide uniformly better performance for (i) basis representation of terms such as 1r(2) in near approach to the singularity at r=0 and (ii) eigenvalue calculation of a bending Hamiltonian taken from a curvilinear model of the ground-state vibrations of nitrosyl chloride.

Multiscale quantum propagation using compact-support wavelets in space and time.

Orthogonal compact-support Daubechies wavelets are employed as bases for both space and time variables in the solution of the time-dependent Schrodinger equation. Initial value conditions are enforced using special early-time wavelets analogous to edge wavelets used in boundary-value problems. It is shown that the quantum equations may be solved directly and accurately in the discrete wavelet representation, an important finding for the eventual goal of highly adaptive multiresolution Schrodinger equation solvers. While the temporal part of the basis is not sharp in either time or frequency, the Chebyshev method used for pure time-domain propagations is adapted to use in the mixed domain and is able to take advantage of Hamiltonian matrix sparseness. The orthogonal separation into different time scales is determined theoretically to persist throughout the evolution and is demonstrated numerically in a partially adaptive treatment of scattering from an asymmetric Eckart barrier.