38 research outputs found
Aspergillus fumigatus Triggers Inflammatory Responses by Stage-Specific β-Glucan Display
Inhalation of fungal spores (conidia) occurs commonly and, in specific circumstances, can result in invasive disease. We investigated the murine inflammatory response to conidia of Aspergillus fumigatus, the most common invasive mold in immunocompromised hosts. In contrast to dormant spores, germinating conidia induce neutrophil recruitment to the airways and TNF-α/MIP-2 secretion by alveolar macrophages. Fungal β-glucans act as a trigger for the induction of these inflammatory responses through their time-dependent exposure on the surface of germinating conidia. Dectin-1, an innate immune receptor that recognizes fungal β-glucans, is recruited in vivo to alveolar macrophage phagosomes that have internalized conidia with exposed β-glucans. Antibody-mediated blockade of Dectin-1 partially inhibits TNF-α/MIP-2 induction by metabolically active conidia. TLR-2- and MyD88-mediated signals provide an additive contribution to macrophage activation by germinating conidia. Selective responsiveness to germinating conidia provides the innate immune system with a mechanism to restrict inflammatory responses to metabolically active, potentially invasive fungal spores
Bi-fractional transforms in phase space
The displacement operator is related to the displaced parity operator through a two dimensional
Fourier transform. Both operators are important operators in phase space
and the trace of both with respect to the density operator gives the Wigner functions
(displaced parity operator) and Weyl functions (displacement operator). The generalisation
of the parity-displacement operator relationship considered here is called
the bi-fractional displacement operator, O(α, β; θα, θβ). Additionally, the bi-fractional
displacement operators lead to the novel concept of bi-fractional coherent states.
The generalisation from Fourier transform to fractional Fourier transform can be
applied to other phase space functions. The case of the Wigner-Weyl function is considered
and a generalisation is given, which is called the bi-fractional Wigner functions,
H(α, β; θα, θβ). Furthermore, the Q−function and P−function are also generalised to
give the bi-fractional Q−functions and bi-fractional P−functions respectively. The
generalisation is likewise applied to the Moyal star product and Berezin formalism for
products of non-commutating operators. These are called the bi-fractional Moyal star
product and bi-fractional Berezin formalism.
Finally, analysis, applications and implications of these bi-fractional transforms
to the Heisenberg uncertainty principle, photon statistics and future applications are
discussed
Unlocking Chain Exchange in Highly Amphiphilic Block Polymer Micellar Systems: Influence of Agitation
Publisher's PDFChain exchange between block polymer micelles in highly selective solvents, such as water, is well-known to be arrested under quiescent conditions, yet this work demonstrates that simple agitation methods can induce rapid chain exchange in these solvents. Aqueous solutions containing either pure poly(butadiene-b-ethylene oxide) or pure poly(butadiene-b-ethylene oxide-d4) micelles were combined and then subjected to agitation by vortex mixing, concentric cylinder Couette flow, or nitrogen gas sparging. Subsequently, the extent of chain exchange between micelles was quantified using small angle neutron scattering. Rapid vortex mixing induced chain exchange within minutes, as evidenced by a monotonic decrease in scattered intensity, whereas Couette flow and sparging did not lead to measurable chain exchange over the examined time scale of hours. The linear kinetics with respect to agitation time suggested a surface-limited exchange process at the air–water interface. These findings demonstrate the strong influence of processing conditions on block polymer solution assemblies.University of Delaware. Department of Chemical & Biomolecular Engineering
Determination of Lithium-Ion Distributions in Nanostructured Block Polymer Electrolyte Thin Films by X‑ray Photoelectron Spectroscopy Depth Profiling
Publisher's PDF.X-ray photoelectron spectroscopy (XPS) depth profiling with C60
þ
sputtering was used to resolve the lithium-ion distribution in the nanometer-scale
domain structures of block polymer electrolyte thin films. The electrolytes of
interest are mixtures of lithium trifluoromethanesulfonate and lamellar-forming
polystyrene poly(oligo(oxyethylene)methacrylate) (PS POEM) copolymer. XPS
depth profiling results showed that the lithium-ion concentration was directly
correlated with the POEM concentration. Furthermore, chemical state and atomic
composition of the film were analyzed through the deconvolution of the C1s signal,
indicating that the lithium ions appear to be uniformly distributed in the POEM domains. Overall, the unique capabilities of C60
þ depth profiling XPS
provide a powerful tool for the analysis of nanostructured polymer thin films in applications ranging from energy storage and generation to surface
coatings and nanoscale templates.University of Delaware. Department of Chemical & Biomolecular Engineering
The O-52 network by molecular design: CECD tetrablock terpolymers
Varying the length of poly(dimethylsiloxane) in poly(cyclohexylethylene-b-ethylene-b-cyclohexylethylene-b-dimethylsiloxane) (CECD) block terpolymers between 0 and 20% produces the sequence of ordered phases: cylindrical-to-network-to-cylindrical. Small-angle X-ray scattering and transmission electron microscopy demonstrate Pnna space group symmetry and a unique network morphology stabilized by the asymmetric molecular architecture and block interactions. These results establish a new design principle for the generation of triply periodic and multiply continuous nano-structured soft materials