Shape-persistent ladder molecules exhibit nanogap-independent conductance in single-molecule junctions.

Molecular electronic devices require precise control over the flow of current in single molecules. However, the electron transport properties of single molecules critically depend on dynamic molecular conformations in nanoscale junctions. Here we report a unique strategy for controlling molecular conductance using shape-persistent molecules.

4D-STEM Mapping of Nanocrystal Reaction Dynamics and Heterogeneity in a Graphene Liquid Cell.

Chemical reaction kinetics at the nanoscale are intertwined with heterogeneity in structure and composition. However, mapping such heterogeneity in a liquid environment is extremely challenging. Here we integrate graphene liquid cell (GLC) transmission electron microscopy and four-dimensional scanning transmission electron microscopy to image the etching dynamics of gold nanorods in the reaction media.

Not All Aggregates Are Made the Same: Distinct Structures of Solution Aggregates Drastically Modulate Assembly Pathways, Morphology, and Electronic Properties of Conjugated Polymers.

Tuning structures of solution-state aggregation and aggregation-mediated assembly pathways of conjugated polymers is crucial for optimizing their solid-state morphology and charge-transport property. However, it remains challenging to unravel and control the exact structures of solution aggregates, let alone to modulate assembly pathways in a controlled fashion. Herein, aggregate structures of an isoindigo-bithiophene-based polymer (PII-2T) are modulated by tuning selectivity of the solvent toward the side chain versus the backbone, which leads to three distinct assembly pathways: direct crystallization from side-chain-associated amorphous aggregates, chiral liquid crystal (LC)-mediated assembly from semicrystalline aggregates with side-chain and backbone stacking, and random agglomeration from backbone-stacked semicrystalline aggregates.

Effects of Fe/S ratio on the kinetics and microbial ecology of an Fe(III)-dosed anaerobic wastewater treatment system.

Effects of Fe(III)/sulfate (Fe/S) ratio on organic carbon oxidation kinetics and microbial ecology of a novel Fe(III)-dosed anaerobic wastewater treatment system were investigated in this study. Fixed-film batch bioreactors under three Fe/S molar ratios (1, 2, and 3) yielded COD oxidation rates that increased with the Fe/S ratio, and estimated Michaelis-Menten model parameters V ranging in 0.47-1.

Tuning Molecular Interactions for Highly Reproducible and Efficient Formamidinium Perovskite Solar Cells via Adduct Approach.

The Lewis acid-base adduct approach has been widely used to form uniform perovskite films, which has provided a methodological base for the development of high-performance perovskite solar cells. However, its incompatibility with formamidinium (FA)-based perovskites has impeded further enhancement of photovoltaic performance and stability. Here, we report an efficient and reproducible method to fabricate highly uniform FAPbI films via the adduct approach.

Structurally Deformed MoS for Electrochemically Stable, Thermally Resistant, and Highly Efficient Hydrogen Evolution Reaction.

The emerging molybdenum disulfide (MoS ) offers intriguing possibilities for realizing a transformative new catalyst for driving the hydrogen evolution reaction (HER). However, the trade-off between catalytic activity and long-term stability represents a formidable challenge and has not been extensively addressed. This study reports that metastable and temperature-sensitive chemically exfoliated MoS (ce-MoS ) can be made into electrochemically stable (5000 cycles), and thermally robust (300 °C) while maintaining synthetic scalability and excellent catalytic activity through physical-transformation into 3D structurally deformed nanostructures.

The Interplay between Trap Density and Hysteresis in Planar Heterojunction Perovskite Solar Cells.

Anomalous current-voltage (J-V) hysteresis in perovskite (PSK) solar cell is open to dispute, where hysteresis is argued to be due to electrode polarization, dipolar polarization, and/or native defects. However, a correlation between those factors and J-V hysteresis is hard to be directly evaluated because they usually coexist and are significantly varied depending on morphology and crystallinity of the PSK layer, selective contacts, and device architecture. In this study, without changing morphology and crystallinity of PSK layer in a planar heterojunction structure employing FACsPbI, a correlation between J-V hysteresis and trap density is directly evaluated by means of thermally induced PbI regulating trap density.

Use of Tumor Necrosis Factor Alpha Inhibitors for Inflammatory Bowel Disease Patients with Concurrent Heart Failure.

Background: Prescribing information for tumor necrosis factor alpha (TNFα) inhibitors, a mainstay of treatment for moderate to severe inflammatory bowel disease (IBD), instructs cautious use in those with heart failure (HF). However, the limited data behind these warnings are inconclusive and should be weighed against mounting evidence demonstrating worse cardiac outcomes in active IBD.

Aims: To assess whether TNFα inhibitor use is reduced in patients with IBD and HF by analyzing physician practice and prescription patterns.

Electrohydrodynamic-assisted Assembly of Hierarchically Structured, 3D Crumpled Nanostructures for Efficient Solar Conversions.

The tantalizing prospect of harnessing the unique properties of graphene crumpled nanostructures continues to fuel tremendous interest in energy storage and harvesting applications. However, the paper ball-like, hard texture, and closed-sphere morphology of current 3D graphitic nanostructure production not only constricts the conductive pathways but also limits the accessible surface area. Here, we report new insights into electrohydrodynamically-generated droplets as colloidal nanoreactors in that the stimuli-responsive nature of reduced graphene oxide can lead to the formation of crumpled nanostructures with a combination of open structures and doubly curved, saddle-shaped edges.

Low temperature excitonic spectroscopy and dynamics as a probe of quality in hybrid perovskite thin films.

We have developed a framework for using temperature dependent static and dynamic photoluminescence (PL) of hybrid organic-inorganic perovskites (PVSKs) to characterize lattice defects in thin films, based on the presence of nanodomains at low temperature. Our high-stability PVSK films are fabricated using a novel continuous liquid interface propagation technique, and in the tetragonal phase (T > 120 K), they exhibit bi-exponential recombination from free charge carriers with an average PL lifetime of ∼200 ns. Below 120 K, the emergence of the orthorhombic phase is accompanied by a reduction in lifetimes by an order of magnitude, which we establish to be the result of a crossover from free carrier to exciton-dominated radiative recombination.

HCV Prevalence in Asian Americans in California.

The World Health Organization estimates that 170 million persons are infected with HCV worldwide, but only 22 million are from the Americas and Europe, compared to 94 million from Asia. HCV prevalence in the general US population is 1.6 %, but data for Asian Americans are limited.