Placental-fetal distribution of carbon particles in a pregnant rabbit model after repeated exposure to diluted diesel engine exhaust

BACKGROUND: Airborne pollution particles have been shown to translocate from the mother's lung to the fetal circulation, but their distribution and internal placental-fetal tissue load remain poorly explored. Here, we investigated the placental-fetal load and distribution of diesel engine exhaust particles during gestation under controlled exposure conditions using a pregnant rabbit model. Pregnant dams were exposed by nose-only inhalation to either clean air (controls) or diluted and filtered diesel engine exhaust (1 mg/m 3) for 2 h/day, 5 days/week, from gestational day (GD) 3 to GD27. At GD28, placental and fetal tissues (i.e., heart, kidney, liver, lung and gonads) were collected for biometry and to study the presence of carbon particles (CPs) using white light generation by carbonaceous particles under femtosecond pulsed laser illumination. RESULTS: CPs were detected in the placenta, fetal heart, kidney, liver, lung and gonads in significantly higher amounts in exposed rabbits compared with controls. Through multiple factor analysis, we were able to discriminate the diesel engine exposed pregnant rabbits from the control group taking all variables related to fetoplacental biometry and CP load into consideration. Our findings did not reveal a sex effect, yet a potential interaction effect might be present between exposure and fetal sex. CONCLUSIONS: The results confirmed the translocation of maternally inhaled CPs from diesel engine exhaust to the placenta which could be detected in fetal organs during late-stage pregnancy. The exposed can be clearly discriminated from the control group with respect to fetoplacental biometry and CP load. The differential particle load in the fetal organs may contribute to the effects on fetoplacental biometry and to the malprogramming of the fetal phenotype with long-term effects later in life

Incorporation of Cesium Lead Halide Perovskites into g-C3N4 for Photocatalytic CO2 Reduction

CsPbBr3 perovskite-based composites so far have been synthesized by postdeposition of CsPbBr3 on a parent material. However, in situ construction offers enhanced surface contact, better activity, and improved stability. Instead of applying a typical thermal condensation at highly elevated temperatures, we report for the first time CsPb(Br x Cl1-x )3/graphitic-C3N4 (CsPbX3/g-C3N4) composites synthesized by a simple and mild solvothermal route, with enhanced efficacy in visible-light-driven photocatalytic CO2 reduction. The composite exhibited a CO production rate of 28.5 μmol g-1 h-1 at an optimized loading amount of g-C3N4. This rate is about five times those of pure g-C3N4 and CsPbBr3. This work reports a new in situ approach for constructing perovskite-based heterostructure photocatalysts with enhanced light-harvesting ability and improved solar energy conversion efficiency.status: publishe

Solar-Driven Metal Halide Perovskite Photocatalysis: Design, Stability, and Performance

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Nanostructured Ag-zeolite Composites as Luminescence-based Humidity Sensors

Small silver clusters confined inside zeolite matrices have recently emerged as a novel type of highly luminescent materials. Their emission has high external quantum efficiencies (EQE) and spans the whole visible spectrum. It has been recently reported that the UV excited luminescence of partially Li-exchanged sodium Linde type A zeolites [LTA(Na)] containing luminescent silver clusters can be controlled by adjusting the water content of the zeolite. These samples showed a dynamic change in their emission color from blue to green and yellow upon an increase of the hydration level of the zeolite, showing the great potential that these materials can have as luminescence-based humidity sensors at the macro and micro scale. Here, we describe the detailed procedure to fabricate a humidity sensor prototype using silver-exchanged zeolite composites. The sensor is produced by suspending the luminescent Ag-zeolites in an aqueous solution of polyethylenimine (PEI) to subsequently deposit a film of the material onto a quartz plate. The coated plate is subjected to several hydration/dehydration cycles to show the functionality of the sensing film.status: publishe

Corrigendum to Photocatalytic carbon oxidation with nitric oxide (vol 166, pg 374, 2015)

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Sunny Days for Perovskite Optoelectronics

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Assessing Photocatalytic Activity at the Nanoscale Using Integrated Optical and Electron Microscopy

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim An integrated optical-electron microscope is presented that enables the in situ study of dynamic processes on photoactive materials. Here, the deposition of metallic silver nanostructures at ZnO photocatalyst particles is monitored in real time under ambient conditions by means of scanning electron microscopy. Zinc oxide crystals are immobilized on an electron transparent silicon nitride window. By passing UV light through an opposing optically transparent window, the zinc oxide is illuminated resulting in the photocatalytic formation of silver nanostructures. Both windows are part of a specially designed liquid cell filled with a dilute aqueous silver nitrate solution. Using the presented system, different electron detectors are evaluated for their ability to provide detailed images despite the interference caused by the liquid surrounding the sample. Special care has to be taken since direct silver reduction from solution induced by the electron beam interferes with the photocatalytic process. Oxygen gas, produced during the photocatalytic reaction, is also shown to complicate the imaging of the dynamic nanoscale processes in the scanning electron microscope. Nevertheless, the integrated approach allows to directly establish structure–activity relationships and to unravel optically induced processes at nanostructured materials.status: publishe

It's a trap! On the nature of localised states and charge trapping in lead halide perovskites

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Fast quantitative time lapse displacement imaging of endothelial cell invasion.

In order to unravel rapid mechano-chemical feedback mechanisms in sprouting angiogenesis, we combine selective plane illumination microscopy (SPIM) and tailored image registration algorithms - further referred to as SPIM-based displacement microscopy - with an in vitro model of angiogenesis. SPIM successfully tackles the problem of imaging large volumes while upholding the spatial resolution required for the analysis of matrix displacements at a subcellular level. Applied to in vitro angiogenic sprouts, this unique methodological combination relates subcellular activity - minute to second time scale growing and retracting of protrusions - of a multicellular systems to the surrounding matrix deformations with an exceptional temporal resolution of 1 minute for a stack with multiple sprouts simultaneously or every 4 seconds for a single sprout, which is 20 times faster than with a conventional confocal setup. Our study reveals collective but non-synchronised, non-continuous activity of adjacent sprouting cells along with correlations between matrix deformations and protrusion dynamics.status: Published onlin

Facet-Dependent Photoreduction on Single ZnO Crystals

Photocatalytic reactions occur at the crystal-solution interface, and hence specific crystal facet expression and surface defects can play an important role. Here we investigate the structure-related photoreduction at zinc oxide (ZnO) microparticles via integrated light and electron microscopy in combination with silver metal photodeposition. This enables a direct visualization of the photoreduction activity at specific crystallographic features. It is found that silver nanoparticle photodeposition on dumbbell-shaped crystals mainly takes place at the edges of O-terminated (0001̅) polar facets. In contrast, on ZnO microrods photodeposition is more homogeneously distributed with an increased activity at {101̅1̅} facets. Additional time-resolved measurements reveal a direct spatial link between the enhanced photoactivity and increased charge carrier lifetimes. These findings contradict previous observations based on indirect, bulk-scale experiments, assigning the highest photocatalytic activity to polar facets. The presented research demonstrates the need for advanced microscopy techniques to directly probe the location of photocatalytic activity.status: publishe