IgG is a major Ig subclass in mucosal secretions of the human female genital tract, where it predominates over the IgA isotype. Despite the abundance of IgG, surprisingly little is known about where and how IgG enters the lumen of the genital tract and the exact role local IgG plays in preventing sexually transmitted diseases. We demonstrate here that the neonatal Fc receptor, FcRn, is expressed in female genital tract epithelial cells of humans and mice and binds IgG in a pH-dependent manner. In vitro we show that FcRn mediates bidirectional IgG transport across polarized human endometrial HEC-1-A monolayers and primary human genital epithelial cells. Furthermore, endosomal acidification appears to be a prerequisite for FcRn-mediated IgG transcytosis; IgG transcytosis was demonstrated in vivo by translocation of systemically administered IgG into the genital lumen in WT but not FcRn-KO mice. The biological relevance of FcRn-transported IgG was demonstrated by passive immunization using herpes simplex virus-2 (HSV-2)-specific polyclonal serum, which conferred significantly higher protection against intravaginal challenge infection by the HSV-2 186 strain in WT mice than in FcRn-KO mice. These studies demonstrate that FcRn-mediated transport is a mechanism by which IgG can act locally in the female genital tract in immune surveillance and in host defense against sexually transmitted diseases.

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This paper presents an automatic method for detecting railway surface defects called "squats" using axle box acceleration (ABA) measurements on trains. The method is based on a series of research results from our group in the field of railway engineering that includes numerical simulations, the design of the ABA prototype, real-life implementation, and extensive field tests. We enhance the ABA signal by identifying the characteristic squat frequencies, using improved instrumentation for making measurements, and using advanced signal processing. The automatic detection algorithm for squats is based on wavelet spectrum analysis and determines the squat locations. The method was validated on the Groningen-Assen track in The Netherlands and accurately detected moderate and severe squats with a hit rate of 100%, with no false alarms. The methodology is also sensitive to small rail surface defects and enables the detection of squats at their earliest stage. The hit rate for small rail surface defects was 78%.

The key to exploiting perovskite nanocrystals (NCs) for long-term practical use in optoelectronic materials and devices lies in the ability to access stable NCs. Herein, we report the crafting of hairy perovskite NCs with a set of markedly improved stabilities by capitalizing on rationally designed star-like molecular bottlebrush trilobes as nanoreactors. An intriguing star-like molecular bottlebrush trilobe, poly­(2-hydroxyethyl methacrylate)-graft-(poly­(acrylic acid)-block-partially cross-linked polystyrene (denoted PHEMA-g-(PAA-b-cPS)) is synthesized. Subsequently, it is employed as a polymeric nanoreactor to direct the growth of green-emitting all-inorganic perovskite CsPbBr3 NCs intimately and stably tethered by partially cross-linked PS “hairs” (i.e., cPS-capped CsPbBr3 NCs). The resulting CsPbBr3 NCs exhibit an array of impressive stabilities against UV irradiation, moisture, heat, and water, due to permanently ligated hydrophobic cPS “hairs” on the surface of CsPbBr3 NCs as a result of the original covalent bonding between PAA and cPS blocks. More importantly, cPS-capped CsPbBr3 NCs manifest outstanding stability in various polar organic solvents. Such greatly improved stability can be attributed to the reduced surface defects enabled by the favorable interaction (i.e., coordination interaction and hydrogen bonding) between CsPbBr3 NCs and polar solvents, which dominates over their dissolution by polar solvents. Such exceptional stabilities impart the use of cPS-capped CsPbBr3 NCs as a selective probe for tracing the presence of Cl–/I– in polar organic solvents. The amphiphilic nonlinear block copolymer nanoreactor strategy can afford easy access to stable perovskite NCs of interest with controlled compositions and surface chemistry. They may find applications in solar cells, LEDs, photodetectors, lasers, bioimaging, biosensors, etc.

a 3D framework. The A-site cations occupy the cavity within the framework. Metal halide perovskites have a relatively soft lattice and a dynamically disordered crystal structure which results in tunable charge-carrier recombination rates and other nonclassical semiconductor characteristics. [1] Metal halide perovskites have been extensively studied for solar energy conversion over the past decade due to their intriguing optoelectronic properties, including near-perfect crystalline structures, [2] tunable direct bandgaps, [3] large absorption coefficient (1.5 × 10 4 cm −1 at 550 nm), [4] high ambipolar mobility (≈20 cm 2 V −1 s −1 ), [5] long carrier diffusion lengths (100-1000 nm; ≈175 µm in MAPbI 3 single crystals) (L eff,e /L eff,h < 1), [6] small exciton binding energy (≈30 meV), [7] high defect tolerance, [8] solution processability, and low processing cost. [9] Notably, the certified power conversion efficiency (PCE) of single-junction perovskite solar cells has rapidly increased from 3.8% in 2009 to 25.2% in 2019. [10] It is also notable that charge carriers within metal halide perovskites can undergo radiative recombination to emit light, making them promising candidates as next-generation light sources for light-emitting diodes (LEDs) [11] and lasers. [12] Bulk perovskite, however, exhibits limited photoluminescence quantum yield (PLQY) due to the presence of mobile ionic defects and small exciton binding energy. [13] In contrast, perovskite nanocrystals (PNCs) possess strong quantum confinement and display improved optoelectronic properties from their bulk counterparts. [14] Notably, metal halide PNCs possess high luminescence, narrow full width at half maximum, and a composition-and size-dependent bandgap. [15] The photoluminescence (PL) of metal halide PNCs can be readily tuned from ultraviolet (UV) to near-infrared wavelengths by simply tailoring their composition or altering their size relative to their Bohr diameters.Hot-injection and ligand-assisted reprecipitation methods represent the two most-developed colloidal synthesis approaches of metal halide PNCs. [13,16] The use of organic capping ligands in synthesis enables nanoscale growth of metal halide perovskite crystals and actively passivates their surface defects, in a manner similar to that of conventional NC Metal halide perovskite nanocrystals (PNCs) have recently garnered tremendous research interest due to their unique optoelectronic properties and promising applications in photovoltaics and optoelectronics. Metal halide PNCs can be combined with polymers to create nanocomposites that carry an array of advantageous characteristics. The polymer matrix can bestow stability, stretchability, and solution-processability while the PNCs maintain their size-, shape-and composition-dependent optoelectronic properties. As such, these nanocomposites possess great promise for next-generation displays, lighting, sensing, biomedical technologies, and energy conversion. The recent advances in metal halide PNC/polymer nanocomposites are summarized here. F...

Thermoresponsive nanoparticles (NPs) represent an important hybrid material comprising functional NPs with temperature-sensitive polymer ligands.S trikingly,s ignificant discrepancies in optical and catalytic properties of thermoresponsive noble-metal NPs have been reported, and have yet to be unraveled. Reported herein is the crafting of Au NPs, intimately and permanently ligated by thermoresponsive poly(N-isopropylacrylamide) (PNIPAM), in situ using as tarlike blockc opolymer nanoreactor as model system to resolve the paradox noted above. As temperature rises,p lasmonic absorption of PNIPAM-capped Au NPs red-shifts with increased intensity in the absence of free linear PNIPAM, whereas ag reater red-shift with decreased intensity occurs in the presence of deliberately introduced linear PNIPAM. Remarkably,t he absence or addition of free linear PNIPAM also accounts for non-monotonic or switchable on/off catalytic performance,respectively,ofPNIPAM-capped Au NPs.

IgE-mediated allergic inflammation occurs when allergens cross-link IgE on the surface of immune cells, thereby triggering the release of inflammatory mediators as well as enhancing Ag presentations. IgE is frequently present in airway secretions, and its level can be enhanced in human patients with allergic rhinitis and bronchial asthma. However, it remains completely unknown how IgE appears in the airway secretions. In this study, we show that CD23 (FcεRII) is constitutively expressed in established or primary human airway epithelial cells, and its expression is significantly upregulated when airway epithelial cells were subjected to IL-4 stimulation. In a transcytosis assay, human IgE or IgE-derived immune complex (IC) was transported across a polarized Calu-3 monolayer. Exposure of the Calu-3 monolayer to IL-4 stimulation also enhanced the transcytosis of either human IgE or the IC. A CD23-specific Ab or soluble CD23 significantly reduced the efficiency of IgE or IC transcytosis, suggesting a specific receptor-mediated transport by CD23. Transcytosis of both IgE and the IC was further verified in primary human airway epithelial cell monolayers. Furthermore, the transcytosed Ag–IgE complexes were competent in inducing degranulation of the cultured human mast cells. Because airway epithelial cells are the first cell layer to come into contact with inhaled allergens, our study implies CD23-mediated IgE transcytosis in human airway epithelial cells may play a critical role in initiating and contributing to the perpetuation of airway allergic inflammation.