Rapid Progression of Pulmonary Blastomycosis in an Untreated Patient of Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is associated with a state of immunosuppression characterized by hypogammaglobulinemia as well as B and T lymphocyte dysfunction. Though opportunistic infections are common in CLL patients, particularly after treatment, reports of infections by endemic dimorphic fungi are very few. Here we report a case of pulmonary blastomycosis in a CLL patient who initially presented with an indolent pulmonary mass lesion. The pulmonary lesions progressed rapidly over a two-week period. The diagnosis was established by transbronchial lung biopsy. He was treated with Amphotericin B lipid complex followed by oral itraconazole and recovered uneventfully. This case illustrates the importance of a timely diagnosis and treatment. The presentation of blastomycosis in immunocompromised patients, diagnosis, and treatment are discussed

Performance simulation of polymer-based nanoparticle and void dispersed photonic structures for radiative cooling

Abstract Passive radiative cooling is an emerging field and needs further development of material. Hence, the computational approach needs to establish for effective metamaterial design before fabrication. The finite difference time domain (FDTD) method is a promising numerical strategy to study electromagnetic interaction with the material. Here, we simulate using the FDTD method and report the behavior of various nanoparticles (SiO2, TiO2, Si3N4) and void dispersed polymers for the solar and thermal infrared spectrums. We propose the algorithm to simulate the surface emissive properties of various material nanostructures in both solar and thermal infrared spectrums, followed by cooling performance estimation. It is indeed found out that staggered and randomly distributed nanoparticle reflects efficiently in the solar radiation spectrum, become highly reflective for thin slab and emits efficiently in the atmospheric window (8–13 µm) over the parallel arrangement with slight variation. Higher slab thickness and concentration yield better reflectivity in the solar spectrum. SiO2-nanopores in a polymer, Si3N4 and TiO2 with/without voids in polymer efficiently achieve above 97% reflection in the solar spectrum and exhibits substrate independent radiative cooling properties. SiO2 and polymer combination alone is unable to reflect as desired in the solar spectrum and need a highly reflective substrate like silver

Finding an alternative diagnosis does not justify increased use of CT-pulmonary angiography

Abstract Background The increased use of computed tomography pulmonary angiography (CTPA) is often justified by finding alternative diagnoses explaining patients’ symptoms. However, this has not been rigorously examined. Methods We retrospectively reviewed CTPA done at our center over an eleven year period (2000 – 2010) in patients with suspected pulmonary embolus (PE). We then reviewed in detail the medical records of a representative sample of patients in three index years – 2000, 2005 and 2008. We determined whether CTPA revealed pulmonary pathology other than PE that was not readily identifiable from the patient’s history, physical examination and prior chest X-ray. We also assessed whether the use of pre-test probability guided diagnostic strategy for PE. Results A total of 12,640 CTPA were performed at our center from year 2000 to 2010. The number of CTPA performed increased from 84 in 2000 to 2287 in 2010, a 27 fold increase. Only 7.6 percent of all CTPA and 3.2 percent of avoidable CTPAs (low or intermediate pre-test probability and negative D-dimer) revealed previously unknown findings of any clinical significance. When we compared 2008 to 2000 and 2005, more CTPAs were performed in younger patients (mean age (years) for 2000: 67, 2005: 63, and 2008: 60, (p=0.004, one–way ANOVA)). Patients were less acutely ill with fewer risk factors for PE. Assessment of pre-test probability of PE and D-dimer measurement were rarely used to select appropriate patients for CTPA (pre-test probability of PE documented in chart (% total) in year 2000: 4.1%, 2005: 1.6%, 2008: 3.1%). Conclusions Our data do not support the argument that increased CTPA use is justified by finding an alternative pulmonary pathology that could explain patients’ symptoms. CTPA is being increasingly used as the first and only test for suspected PE.</p

Understanding the Chemical Nature of the Buried Nanostructures in Low Thermal Conductive Sb-Doped SnTe by Variable-Energy Photoelectron Spectroscopy

Nanoprecipitates embedded in a matrix of thermoelectric materials decrease the lattice thermal conductivity significantly by extensive heat carrying phonon scattering. Recently, two-dimensional layered intergrowth nanostructures of Sn$_m$Sb$_{2n}$Te$_{3n+m}$ embedded in SnTe matrix have provided record low lattice thermal conductivity in SnTe, but an understanding of the chemical nature of these layered nanostructures is still not clear. Herein, we studied the chemical nature of the intergrowth nanostructures of a series Sb-doped SnTe by variable-energy X-ray photoelectron spectroscopy at synchrotron, which is well known to probe buried interfaces and embedded nanostructures. The primary oxidation states of Sb, Sn, and Te in these intergrowth structures are found to be in +3, +2, and −2, respectively, which is expected from the composition. However, both the Sn and Sb are found to be slightly oxidized in the surface. From the intensity variation with photon energy, we have found a thin layer of SnO$_2$ (∼4.5 nm) on the sample surfaces and the thickness decreases with Sb doping. Te is also found in 0 oxidation states, which corroborates with the variation of Sn vacancies with Sb doping. The valence band features near the edge do not change significantly with Sb doping. This understanding of the chemical nature of low lattice thermal conductive Sb-doped SnTe will help further to design the thermoelectric materials with their surface phenomenon

Internal Heterostructure of Anion-Exchanged Cesium Lead Halide Nanocubes

All-inorganic cesium lead halide (CsPbX₃; X = Cl, Br, and I) perovskite nanocubes (NCs) exhibit fascinating optical and optoelectronic properties. Postsynthesis anion exchange by mixing NCs with reactive anion species has emerged as a unique strategy to control their composition and band gap. For example, we started with CsPbBr₃ NCs with intense green emission, and then anion exchange with iodide ions yields CsPb­(Br/I)₃ mixed halides and CsPbI₃ with emission color systematically varying in the green-red region. However, the internal structure of the anion-exchanged perovskite NCs is not probed. It is believed that the NCs possess a homogeneous alloyed composition, but X-ray diffraction pattern could not give evidence for such alloy formation, because the crystal structure also varies with anion composition. Here, we elucidate the internal heterostructure of anion-exchanged NCs using variable energy hard X-ray photoelectron spectroscopy. The results show that, in contrast to a homogeneous alloy, there is a significant inhomogeneity in the composition across the radius of NCs. The surface of CsPb­(Br/I)₃ NCs is rich with exchanged iodide ions, whereas the core is rich with native bromide ions. Even CsPbI₃ NCs obtained after assumed complete anion exchange show a small amount of bromide ions in the core. This finding of gradient internal heterostructure inside the anion-exchanged NCs will be important for future understanding of electronic properties and stability-related issues of CsPbX₃ NCs