A Closed Class of Hydrodynamical Solutions for the Collective Excitations of a Bose-Einstein Condensate

A trajectory approach is taken to the hydrodynamical treatment of collective excitations of a Bose-Einstein condensate in a harmonic trap. The excitations induced by linear deformations of the trap are shown to constitute a broad class of solutions that can be fully described by a simple nonlinear matrix equation. An exact closed-form expression is obtained for the solution describing the mode {n=0, m=2} in a cylindrically symmetric trap, and the calculated amplitude-dependent frequency shift shows good agreement with the experimental results of the JILA group.Comment: RevTex, 4 pages, 1 eps figure, identical to the published versio

Preliminary assessment of cardiac short term safety and efficacy of manganese chloride for cardiovascular magnetic resonance in humans

<p>Abstract</p> <p>Background</p> <p>Manganese based agents are intracellular and accumulate inside myocytes allowing for different imaging strategies compared to gadolinium contrasts. While previous agents release manganese very slowly in the circulation, MnCl₂allows for rapid Mn2⁺uptake in myocytes, creating a memory effect that can be potentially explored. Data on animal models are very encouraging but the safety and efficacy of this approach in humans has not yet been investigated. Therefore, our objectives were to study the safety and efficacy of a rapid infusion of manganese chloride (MnCl₂) for cardiovascular magnetic resonance (CMR) in humans.</p> <p>Methods</p> <p>Fifteen healthy volunteers underwent a CMR scan on a 1.5 T scanner. Before the infusion, cardiac function was calculated and images of a short axis mid-ventricular slice were obtained using a 2D and 3D gradient-echo inversion recovery (GRE-IR) sequence, a phase-sensitive IR sequence and a single breath-hold segmented IR prepared steady-state precession acquisition for T₁calculations. MnCl₂was infused over three minutes at a total dose of 5 μMol/kg. Immediately after the infusion, and at 15 and 30 minutes later, new images were obtained and cardiac function re-evaluated.</p> <p>Results</p> <p>There was a significant decrease in T₁values compared to baseline, sustained up to 30 minutes after the MnCl₂infusion (pre,839 ± 281 ms; 0 min, 684 ± 99; 15 min, 714 ± 168; 30 min, 706 ± 172, P = 0.003). The 2D and 3D GRE-IR sequence showed the greatest increase in signal-to-noise ratio compared to the other sequences (baseline 6.6 ± 4.2 and 9.7 ± 5.3; 0 min, 11.3 ± 4.1 and 15.0 ± 8.7; 15 min, 10.8 ± 4.0 and 16.9 ± 10.2; 30 min, 10.6 ± 5.2 and 16.5 ± 8.3, P < 0.001 for both). There was a slight increase in systolic pressure and heart rate after three and four minutes of the infusion with normalization of these parameters thereafter. Patients showed good tolerance to MnCl₂with no major adverse events, despite all reporting transient facial flush.</p> <p>Conclusions</p> <p>In the short term, MnCl₂appears safe for human use. It effectively decreases myocardium T₁, maintaining this effect for a relatively long period of time and allowing for the development of new imaging strategies in CMR, especially in ischemia research.</p

第859回 千葉医学会例会・第26回 肺癌研究施設例会 23.

PURPOSE:Perfusion analysis from first-pass contrast enhancement kinetics requires modeling tissue contrast exchange. This study presents a new approach for numerical implementation of the tissue homogeneity model, incorporating flexible distance steps along the capillary (NTHf). METHODS:The proposed NTHf model considers contrast exchange in fluid packets flowing along the capillary, incorporating flexible distance steps, thus allowing more efficient and stable calculations of the transit of tracer through the tissue. We prospectively studied 8 patients (62 ± 13 years old) with suspected CAD, who underwent first-pass perfusion CMR imaging at rest and stress prior to angiography. Myocardial blood flow (MBF) and myocardial perfusion reserve index (MPRI) were estimated using both the NTHf and the conventional adiabatic approximation of the TH models. Coronary artery lesions detected at angiography were clinically assigned to one of three categories of stenosis severity ('insignificant', 'mild to moderate' and 'severe') and related to corresponding myocardial territories. RESULTS:The mean MBF (ml/g/min) at rest/stress and MPRI were 0.80 ± 0.33/1.25 ± 0.45 and 1.68 ± 0.54 in the insignificant regions, 0.74 ± 0.21/1.09 ± 0.28 and 1.54 ± 0.46 in the mild to moderate regions, and 0.79 ± 0.28/0.63 ± 0.34 and 0.85 ± 0.48 in the severe regions, respectively. The correlation coefficients of MBFs at rest/stress and MPRI between the NTHf and AATH models were r = 0.97/0.93 and r = 0.91, respectively. CONCLUSIONS:The proposed NTHf model allows efficient quantitative analysis of the transit of tracer through tissue, particularly at higher flow. Results of initial application to MRI of myocardial perfusion in CAD are encouraging

The Feynman path integral approach to atomic interferometry. A tutorial

Many problems of current interest in atomic interferometry lend themselves to a path integral treatment. We present a practical guide to solving such problems, taking as examples the gravitational experiments of Kasevich and Chu, and the atomic equivalents of the Sagnac and Aharonov-Bohm effects

Flow Patterns and Particle Residence Times in the Oral Cavity during Inhaled Drug Delivery

Pulmonary drug delivery aims to deliver particles deep into the lungs, bypassing the mouth&ndash;throat airway geometry. However, micron particles under high flow rates are susceptible to inertial impaction on anatomical sites that serve as a defense system to filter and prevent foreign particles from entering the lungs. The aim of this study was to understand particle aerodynamics and its possible deposition in the mouth&ndash;throat airway that inhibits pulmonary drug delivery. In this study, we present an analysis of the aerodynamics of inhaled particles inside a patient-specific mouth&ndash;throat model generated from MRI scans. Computational Fluid Dynamics with a Discrete Phase Model for tracking particles was used to characterize the airflow patterns for a constant inhalation flow rate of 30 L/min. Monodisperse particles with diameters of 7 &mu;m to 26 &mu;m were introduced to the domain within a 3 cm-diameter sphere in front of the oral cavity. The main outcomes of this study showed that the time taken for particle deposition to occur was 0.5 s; a narrow stream of particles (medially and superiorly) were transported by the flow field; larger particles &gt; 20 &mu;m deposited onto the oropharnyx, while smaller particles &lt; 12 &mu;m were more disperse throughout the oral cavity and navigated the curved geometry and laryngeal jet to escape through the tracheal outlet. It was concluded that at a flow rate of 30 L/min the particle diameters depositing on the larynx and trachea in this specific patient model are likely to be in the range of 7 &mu;m to 16 &mu;m. Particles larger than 16 &mu;m primarily deposited on the oropharynx

Quantitative Proton Spectroscopy of the Testes at 3 T: Toward a Noninvasive Biomarker of Spermatogenesis.

OBJECTIVES: The aim of this study was to compare testicular metabolite concentrations between fertile control subjects and infertile men. MATERIALS AND METHODS: Single voxel proton magnetic resonance spectroscopy (H-MRS) was performed in the testes with and without water suppression at 3 T in 9 fertile control subjects and 9 infertile patients (8 with azoospermia and 1 with oligospermia). In controls only, the T1 and T2 values of water and metabolites were also measured. Absolute metabolite concentrations were calculated using the unsuppressed water signal as a reference and correcting for the relative T1 and T2 weighting of the water and metabolite signals. RESULTS: Testicular T1 values of water, total choline, and total creatine were 2028 ± 125 milliseconds, 1164 ± 105 milliseconds, and 1421 ± 314 milliseconds, respectively (mean ± standard deviation). T2 values were 154 ± 11 milliseconds, 342 ± 53 milliseconds, and 285 ± 167 milliseconds, respectively. Total choline concentration was lower in patients (mean, 1.5 mmol/L; range, 0.9-2.1 mmol/L) than controls (mean, 4.4 mmol/L; range, 3.2-5.7 mmol/L; P = 4 × 10). Total creatine concentration was likewise reduced in patients (mean, 1.1 mmol/L; range, undetectable -2.7 mmol/L) compared with controls (mean, 3.6 mmol/L; range, 2.5-4.7 mmol/L; P = 1.6 × 10). The myo-inositol signal normalized to the water reference was also lower in patients than controls (P = 4 × 10). CONCLUSIONS: Testicular metabolite concentrations, measured by proton spectroscopy at 3 T, may be valuable as noninvasive biomarkers of spermatogenesis

NTH_<i>f</i> and AATH results: MBF and MPRI corresponding to percent diameter stenosis of coronary lesion.

<p>NTH_<i>f</i> and AATH results: MBF and MPRI corresponding to percent diameter stenosis of coronary lesion.</p