Infliximab therapy of relapsing tracheal stenosis in a pediatric patient with granulomatosis with polyangiitis: a case report

Background Granulomatosis with polyangiitis is a granulomatous, necrotizing small-vessel vasculitis affecting both children and adults. However, subglottic tracheal stenosis appears more frequently in the pediatric cohort. To date, granulomatosis with polyangiitis is often treated with steroids, cyclophosphamide, azathioprine, or rituximab, but tumor-necrosis-factor-α-antagonistic drugs are increasingly gaining significance in treatment of refractory cases. Case presentation We report the case of a 15-year-old Caucasian male diagnosed with proteinase-3-positive granulomatosis with polyangiitis with acute shortness of breath. X-ray and magnet resonance imaging showed extensive subglottic narrowing. Forced expiratory volume in 1 s was reduced to 50% of age norm, with massively increased effective airway resistance. The patient initially responded very well to high-dose steroids and maintenance therapy with azathioprine. He was subsequently treated with four doses of rituximab, and levels of proteinase 3 antibodies normalized. After 6 months of clinical remission, the patient presented again with acute respiratory symptoms. Again, he was treated with high-dose steroids, but showed poor clinical response this time. Therefore, we decided to commence a tumor-necrosis-factor-α-antagonistic treatment with infliximab, under which our patient achieved clinical remission and normalization of lung function parameters. Conclusions The use of tumor-necrosis-factor-α-antagonistic agents might be a promising alternative for the treatment of refractory tracheal stenosis in pediatric patients with granulomatosis with polyangiitis

Solution synthesis of nanoparticular binary transition metal antimonides.

The preparation of nanoengineered materials with controlled nanostructures, for example, with an anisotropic phase segregated structure or a regular periodicity rather than with a broad range of interparticle distances, has remained a synthetic challenge for intermetallics. Artificially structured materials, including multilayers, amorphous alloys, quasicrystals, metastable crystalline alloys, or granular metals, are mostly prepared using physical gas phase procedures. We report a novel, powerful solution-mediated approach for the formation of nanoparticular binary antimonides based on presynthesized antimony nanoparticles. The transition metal antimonides M-Sb (M = Co, Ni, Cu(2), Zn) were obtained with sizes ranging from 20 and 60 nm. Through careful control of the reaction conditions, single-phase nanoparticular antimonides were synthesized. The nanophases were investigated by powder X-ray diffraction and (high resolution) electron microscopy. The approach is based on activated metal nanoparticles as precursors for the synthesis of the intermetallic compounds. X-ray powder diffraction studies of reaction intermediates allowed monitoring of the reaction kinetics. The small particle size of the reactants ensures short diffusion paths, low activation barriers, and low reaction temperatures, thereby eliminating solid-solid diffusion as the rate-limiting step in conventional bulk-scale solid-state synthesis

Thermoelectric properties of spark-plasma sintered nanoparticular FeSb2 prepared via a solution chemistry approach.

Nanoparticular FeSb2 was prepared in solution from cyclopentadienyl iron(ii) dicarbonyl dimer Fe(Cp(CO)2)2 and antimony nanoparticles. Spark plasma sintering was used as consolidation method to maintain the particle size. The thermoelectric performance of FeSb2 is limited by its high thermal conductivity. In this work, the thermal conductivity was suppressed by nearly 80\% compared to the bulk value by introducing grain boundary scattering of phonons on the nanoscale. The thermoelectric properties of the consolidated FeSb2 emphasize the possibility of altering thermal transport of promising thermoelectric compounds by phonon scattering by engineering the interfaces at the nanoscale

Solution synthesis of a new thermoelectric Zn(1+x)Sb nanophase and its structure determination using automated electron diffraction tomography.

Engineering materials with specific physical properties have recently focused on the effect of nanoscopic inhomogeneities at the 10 nm scale. Such features are expected to scatter medium- and long-wavelength phonons thereby lowering the thermal conductivity of the system. Low thermal conductivity is a prerequisite for effective thermoelectric materials, and the challenge is to limit the transport of heat by phonons, without simultaneously decreasing charge transport. A solution-phase technique was devised for synthesis of thermoelectric "Zn(4)Sb(3)" nanocrystals as a precursor for phase segregation into ZnSb and a new Zn-Sb intermetallic phase, Zn(1+delta)Sb, in a peritectoid reaction. Our approach uses activated metal nanoparticles as precursors for the synthesis of this intermetallic compound. The small particle size of the reactants ensures minimum diffusion paths, low activation barriers, and low reaction temperatures, thereby eliminating solid-solid diffusion as the rate-limiting step in conventional bulk-scale solid-state synthesis. Both phases were identified and structurally characterized by automated electron diffraction tomography combined with precession electron diffraction. An ab initio structure solution based on electron diffraction data revealed two different phases. The new pseudo-hexagonal phase, Zn(1+delta)Sb, was identified and classified within the structural diversity of the Zn-Sb phase diagram

Enhanced Debye level in nano Zn1+xSb, FeSb2, and NiSb: Nuclear inelastic spectroscopy on 121^{121} Sb

The121 Sb partial density of phonon states (DPS) in nanopowder antimonides were obtained with nuclear inelastic scattering on inline image, inline image, and NiSb prepared by a wet chemistry route. The DPS is compared with the bulk counterpart. An increase of the Debye level indicative of a decrease of the isothermal speed of sound is systematically observed. This observation reveals that the decrease in speed of sound observed in nanostructured thermoelectric materials is not restricted to sintered nanocomposites