Hemodynamic Assessment of Celiaco-mesenteric Anastomosis in Patients with Pancreaticoduodenal Artery Aneurysm Concomitant with Celiac Artery Occlusion using Flow-sensitive Four-dimensional Magnetic Resonance Imaging

ObjectivesMany pancreaticoduodenal artery (PDA) aneurysms are associated with celiac artery (CA) stenosis. The pathogenesis of PDA aneurysm may be associated with hemodynamic changes due to CA stenosis/occlusion. The aim of this study was to assess the hemodynamic changes of celiaco-mesenteric anastomosis in patients with PDA aneurysms concomitant with CA occlusion using four-dimensional flow-sensitive magnetic resonance imaging (4D-Flow).Methods4D-Flow was performed preoperatively on five patients. Seven age- and sex-matched individuals were used as controls. Hemodynamic parameters such as flow volume and maximum flow velocity in PDAs, gastroduodenal arteries, common hepatic arteries, and superior mesenteric arteries were compared between both groups. Wall shear stress (WSS) and oscillatory shear index (OSI) were mapped in both groups.ResultsIn the patient group, 4D-Flow identified retrograde flow of both gastroduodenal arteries and common hepatic arteries. Heterogeneous distribution patterns of both WSS and OSI were identified across the entire PDA in the patient group. OSI mapping showed multiple regions with extremely high OSI values (OSI > 0.3) in all patients. All PDA aneurysms, which were surgically resected, were atherosclerotic.Conclusions4D-Flow identified hemodynamic changes in celiaco-mesenteric arteries in patients with PDA aneurysms with concomitant CA occlusion. These hemodynamic changes may be associated with PDA aneurysm formation

Selected Topics in Three- and Four-Nucleon Systems

Two different aspects of the description of three- and four-nucleon systems are addressed. The use of bound state like wave functions to describe scattering states in $N-d$ collisions at low energies and the effects of some of the widely used three-nucleon force models in selected polarization observables in the three- and four-nucleon systems are discussed.Comment: Presented at the 21st European Conference on Few-Body Problems in Physics, Salamanca, Spain, 30 August - 3 September 201

Microscopic NN→NN∗(1440)NN\to NN^{\ast}(1440) transition potential: Determination of πNN∗(1440)\pi NN^{\ast}(1440) and σNN∗(1440)\sigma NN^{\ast}(1440) coupling constants

A $NN\to NN^{\ast}(1440)$ transition potential, based on an effective quark-quark interaction and a constituent quark cluster model for baryons, is derived in the Born-Oppenheimer approach. The potential shows significant differences with respect to those obtained by a direct scaling of the nucleon-nucleon interaction. From its asymptotic behavior we extract the values of $\pi NN^{\ast}(1440)$ and $\sigma NN^{\ast}(1440)$ coupling constants in a particular coupling schemeComment: 15 eps figures, Accepted for publication in Phys. Rev.

Nonlocal calculation for nonstrange dibaryons and tribaryons

We study the possible existence of nonstrange dibaryons and tribaryons by solving the bound-state problem of the two- and three-body systems composed of nucleons and deltas. The two-body systems are $NN$, $N\Delta$, and $\Delta\Delta$, while the three-body systems are $NNN$, $NN\Delta$, $N\Delta\Delta$, and $\Delta\Delta\Delta$. We use as input the nonlocal $NN$, $N\Delta$, and $\Delta\Delta$ potentials derived from the chiral quark cluster model by means of the resonating group method. We compare with previous results obtained from the local version based on the Born-Oppenheimer approximation.Comment: 19 pages. To be published in Physical Review

Dynamical Casimir effect without boundary conditions

The moving-mirror problem is microscopically formulated without invoking the external boundary conditions. The moving mirrors are described by the quantized matter field interacting with the photon field, forming dynamical cavity polaritons: photons in the cavity are dressed by electrons in the moving mirrors. The effective Hamiltonian for the polariton is derived, and corrections to the results based on the external boundary conditions are discussed.Comment: 12 pages, 2 figure

Population genomics of yams: evolution and domestication of Dioscorea species

Published online: 21 Aug 2021Yam is a collective name of tuber crops belonging to the genus Dioscorea. Yam is important not only as a staple food crop but also as an integral component of society and culture of the millions of people who depend on it. However, due to its regional importance, yam has long been regarded as an “orphan crop” lacking a due global attention. Although this perception is changing with recent advances in genomics technologies, domestication processes of most yam species are still ambiguous. This is mainly due to the complicated evolutionary history of Dioscorea species caused by frequent hybridization and polyploidization, which is possibly caused by dioecy that imposed obligate outcrossing to the species of Dioscorea. In this chapter, we provide an overview of the evolution of Dioscorea and address the domestication of yam from population genomics perspectives by focusing on the processes of hybridization and polyploidization. A review is given to the recent population genomics studies on the hybrid origin of D. rotundata in West and Central Africa, the global dispersion of D. alata through human migrations, and the whole-genome duplication of the South America species of D. trifida. In the end, we give a summary of current understanding of sex-determination system in Dioscorea

Response of Mica to Weakly Interacting Massive Particles

We calculate spin-dependent cross sections for the scattering from mica of hypothetical weakly interacting dark-matter particles such as neutralinos. The most abundant odd-A isotopes in mica, Al27 and K39, require different shell-model treatments. The calculated cross sections will allow the interpretation of ongoing experiments that look for tracks due to the interaction of dark-matter particles with nuclei in ancient mica.Comment: 11 pages, RevTex, 2 uuencoded figures, submittted to Phys. Rev.

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results