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We studied the magnetic excitations in the quasi-one-dimensional (q-1D) ladder subsystem of Sr14−xCaxCu24O41 (SCCO) using Cu L3-edge resonant inelastic X-ray scattering (RIXS). By comparing momentum-resolved RIXS spectra with high (x = 12.2) and without (x = 0) Ca content, we track the evolution of the magnetic excitations from collective two-triplon (2 T) excitations (x = 0) to weakly-dispersive gapped modes at an energy of 280 meV (x = 12.2). Density matrix renormalization group (DMRG) calculations of the RIXS response in the doped ladders suggest that the flat magnetic dispersion and damped excitation profile observed at x = 12.2 originates from enhanced hole localization. This interpretation is supported by polarization-dependent RIXS measurements, where we disentangle the spin-conserving ΔS = 0 scattering from the predominant ΔS = 1 spin-flip signal in the RIXS spectra. The results show that the low-energy weight in the ΔS = 0 channel is depleted when Sr is replaced by Ca, consistent with a reduced carrier mobility. Our results demonstrate that off-ladder impurities can affect both the low-energy magnetic excitations and superconducting correlations in the CuO4 plaquettes. Finally, our study characterizes the magnetic and charge fluctuations in the phase from which superconductivity emerges in SCCO at elevated pressures. [ABSTRACT FROM AUTHOR]

Geothermal energy is one of the potential energy resources to meet future energy demand keeping environmental pollution under control. This paper presents the use of geothermal energy for space heating from energy pile. An energy pile with a single U tube heat exchanger of polyethylene (PE) pipe was modeled in this study. The effect of pile and heat exchanger properties on the total heat extraction was studied by the finite element analysis using COMSOL Multiphysics. The 3D model was developed and validated based on the literature reported results of an experimental thermal performance of a borehole equipped with a single and double U tube heat exchanger. Tetrahedral elements were considered for simulation of a 3D model. The model of a single energy pile of certain dimensions with different soil layers was considered, each soil layers were associated with different temperature. The effect of various parameters such as the length of concrete pile, the diameter of concrete pile, the thickness of U pipe, the inner diameter of U pipe and velocity of fluid inside the U pipe on amount of heat extraction was studied for an energy pile equipped with a single U tube heat exchanger. It was observed that the most influential parameters in increasing the outlet temperature of the heat exchanger loop are the diameter of the concrete pile, the inner diameter of U pipe and the velocity of fluid inside the U pipe.

Abstract Self-assembled InAs quantum dots (QDs) were grown on germanium substrates by metal organic chemical vapor deposition technique. Effects of growth temperature and InAs coverage on the size, density, and height of quantum dots were investigated. Growth temperature was varied from 400 to 450 °C and InAs coverage was varied between 1.40 and 2.35 monolayers (MLs). The surface morphology and structural characteristics of the quantum dots analyzed by atomic force microscope revealed that the density of the InAs quantum dots first increased and then decreased with the amount of InAs coverage; whereas density decreased with increase in growth temperature. It was observed that the size and height of InAs quantum dots increased with increase in both temperature and InAs coverage. The density of QDs was effectively controlled by growth temperature and InAs coverage on GaAs buffer layer.

A Spanish-speaking farm worker with type 2 diabetes mellitus presented to our institution with an ulcerating tongue lesion. He was initially evaluated for possible squamous cell carcinoma; however, histologic examination revealed coccidioidomycosis. Coccidioidal titers were elevated and consistent with disseminated disease, although the patient had no systemic symptoms and clinical evaluation was negative. He was ultimately treated with intravenous and oral antifungal medication, which was followed by improvement of his tongue lesion. [ABSTRACT FROM AUTHOR]

Pulmonary alveolar proteinosis (PAP) is a rare disorder that may lead to respiratory failure or death. Purpose: We are describing unusual occurrence of alveolar proteinosis in three lung transplant recipients. Since the January 2000, 60 transplants were done at Baylor College of Medicine affiliated programs. Three patients (5%) developed PAP with dyspnea, pulmonary infiltrates, and hypoxemia. A 71 yo M with left single lung transplantation for UIP developed severe respiratory failure was re-transplanted, but died of post-operative complications. He had PAP in his first allograft but not the native fibrotic lung. A 64 yo female with primary pulmonary hypertension and 41 yo man with alpha-1 antitrypsin deficiency had increasing dyspnea, pulmonary infiltrates and increased alveolar-arterial oxygen gradient. Transbronchial biopsies showed intra-alveolar periodic acid-Schiff (PAS) -positive acellular lipoproteinaceous material typical of PAP. They are started on subcutaneous injection of GM-CSF for treatment. Conclusion: PAP may be more common in lung transplant recipients than general population due to macrophage dysfunction caused by immunosuppressants. Since it is potentially treatable with either GM-CSF or whole lung lavage, attention should be paid to differentiate PAP from other forms of chronic non-infectious causes of respiratory failure including bronchiolitis obliterans. [ABSTRACT FROM AUTHOR]