Interleukin‐17 Mediated Inflammatory Responses Are Required for Ultraviolet Radiation‐Induced Immune Suppression

Ultraviolet radiation (UVR) induces immunosuppression and is a major factor for development of skin cancer. Numerous efforts have been made to determine mechanisms for UVR‐induced immunosuppression and to develop strategies for prevention and treatment of UVR‐induced cancers. In the current study, we use IL‐17 receptor (IL‐17R) deficient mice to examine whether IL‐17 mediated responses have a role in UVB (290–320)‐induced immunosuppression of contact hypersensitivity responses. Results demonstrate that IL‐17 mediated responses are required for UVB‐induced immunosuppression of contact hypersensitivity responses. The systemic immune suppression and development of regulatory T cells are inhibited in UVB‐treated IL‐17R deficient mice compared to wild‐type animals. The deficiency in IL‐17R inhibits the infiltration and development of a tolerogenic myeloid cell population in UVB‐treated skin, which expresses CD11b and Gr‐1 and produces reactive oxygen species. We speculate that the development of the tolerogenic myeloid cells is dependent on IL‐17‐induced chemokines and inflammatory mediators in UVB‐treated skin. The inhibition of the tolerogenic myeloid cells may be attributed to the suppression of regulatory T cells in UVR‐treated IL‐17R^?/? mice. The findings may be exploited to new strategies for prevention and treatment of UVR‐induced skin diseases and cancers.     

Ultraviolet Radiation‐Induced Downregulation of SERCA2 Mediates Activation of NLRP3 Inflammasome in Basal Cell Carcinoma

Basal cell carcinomas (BCCs) account for majority of skin malignancies in the United States. The incidence of BCCs is strongly associated with exposure of ultraviolet (UV) radiation. Nucleotide‐binding domain, leucine‐rich‐repeat‐containing family, pyrin domain‐containing 3 (NLRP3) inflammasome plays an important role in innate immune responses. Different stimuli such as toxins, microorganisms and particles released from injured cells activate the NLRP3 inflammasome. Activated NLRP3 results in activation of caspase‐1, which cleaves pro‐IL‐1β to active IL‐1β. In this study, we have shown that NLRP3 is expressed in human basal cell carcinomas. The proximal steps in activation of NLRP3 inflammasome are not well understood. Here, we have attempted to elucidate a critical role for Ca²⁺ mobilization in activation of the NLRP3 inflammasome by UVB exposure using HaCaT keratinocytes. We have demonstrated that UVB exposure blocks Ca²⁺ mobilization by downregulating the expression of sarco/endoplasmic reticulum Ca²⁺‐ATPase (SERCA2), a component of store‐operated Ca²⁺ entry that leads to activation of the NLRP3 inflammasome.     

Probing PAH formation chemical kinetics from benzene and toluene pyrolysis in a single-pulse shock tube

Benzene and toluene were pyrolyzed under highly argon-diluted conditions at a nominal pressure of 20 bar in a single-pulse shock tube coupled to gas chromatography/gas chromatography–mass spectrometry (GC/GC–MS) diagnostics. Concentration evolutions of polycyclic aromatic hydrocarbon (PAH) intermediates were measured in a temperature range of 1100–1800 K by analyzing the post-shock gas mixtures. Different PAH speciation behaviors, regarding types, concentrations and formation temperature windows, were observed in the two reaction systems. A kinetic model was proposed to predict and interpret the measurements. Through a combination of experimental and modeling efforts, PAH formation patterns from species pools of benzene and toluene pyrolysis were illustrated. In both cases, channels leading to PAHs basically originate from the respective fuel radicals, phenyl and benzyl. Due to the higher thermal stability of benzene, the production of phenyl, and thus most PAH species, occur in higher temperature windows, in comparison to the case of toluene. In benzene pyrolysis, benzyne participates in the formation of crucial PAH species such as naphthalene and acenaphthylene. Phenyl self-recombination takes considerable carbon flux into biphenyl, which serves as an important intermediate leading to acenaphthylene through hydrogen loss and ring closure. The resonantly-stabilized benzyl is abundant in toluene pyrolysis, and its decomposition further produces other resonantly-stabilized radicals such as fulvenallenyl and propargyl. Barrierless addition reactions among these radicals are found to be important sources of PAHs. Fuel-specific pathways have pronounced effects on PAH speciation behaviors, particularly at lower temperatures where fuel depletion is not completed within the reaction time of 4.0 ms. Contributions from the commonly existing Hydrogen-Abstraction-Carbon-Addition (HACA) routes increase with the temperature in both cases.     

Electrochemical synthesis and characterization of thiophene conducting polymer in aqueous micellar medium

In opposite with the usually applied synthesis in organic media, the polymerization of bithiophene in aqueous media has been studied. The use of a non-ionic surfactant (polyoxyethylene octyl phenyl ether (Triton X-100)) is useful not only to solubilize the hydrophobic monomer but it is also important to incorporate various—biologically and catalytically active—additives. In this paper, the optimization of the polymerization conditions as well as the characterization of the electrochemical, spectral and mass exchange behavior of these composite films is summarized. The layers have shown imperceptible electroactivity in monomer-free aqueous LiClO₄ solutions, and electrochemical quartz crystal microbalance (EQCM) studies exhibited scarce ion movements, caused assumingly by the fact that the dopant species—moving together with their hydrate shell in the aqueous media—could not penetrate into the hydrophobic film. In contrast, nice reversible redox transformation could be obtained in organic medium such as acetonitrile, where—according to the EQCM results—the charge carrier formation/depletion is accompanied by the incorporation/removal of ClO₄ ^? anions. In this solution, the spectral changes have proved the transformation into the conducting state, connected to both mono- and di-cation forms. The incorporation of the surfactant has been demonstrated by the extraordinary surface morphology of the polybithiophene (pBT) films, characterized by scanning electron microscopy. The elementary composition of the curious shell-shaped objects, monitored by energy dispersive X-ray spectroscopy (EDX), evidenced the presence of Triton X-100 by the increased C/S ratio compared to neat polybithiophene, while the Cl/S data reflected the changes connected to the doping level as a consequence of ClO₄ ^? anion movements. Moreover, ex situ attenuated total reflectance (ATR) FT–IR measurements clearly showed the existence of C―O bonds, also proving the successful functionalization by the surfactant, built permanently into the redox active films.