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There is an ongoing global effort to advance emerging perovskite solar cells (PSCs), and many of these endeavours are focused on developing new compositions, processing methods and passivation strategies. In particular, the use of passivators to reduce the defects in perovskite materials has been demonstrated to be an effective approach for enhancing the photovoltaic performance and long-term stability of PSCs. Organic passivators have received increasing attention since the late 2010s as their structures and properties can readily be modified. First, this Review discusses the main types of defect in perovskite materials and reviews their properties. We examine the deleterious impact of defects on device efficiency and stability and highlight how defects facilitate extrinsic degradation pathways. Second, the proven use of different passivator designs to mitigate these negative effects is discussed, and possible defect passivation mechanisms are presented. Finally, we propose four specific directions for future research, which, in our opinion, will be crucial for unlocking the full potential of PSCs using the concept of defect passivation. Defect passivation is a key concept for optimizing the performance of perovskite solar cells. This Review summarizes our understanding of defects in perovskites and highlights the most promising strategies and materials used for their passivation.

Seegrasses are a polyphyletic group of angiosperm plants, which evolved from early monocotyledonous land plants and returned to the marine environment around 140 million years ago. Today, seagrasses comprise the five families , , , and and form important coastal ecosystems worldwide. Despite of this ecological importance, the existing literature on adaption of these angiosperms to the marine environment and especially their cell wall composition is limited up to now. A unique feature described for some seagrasses is the occurrence of polyanionic, low-methylated pectins mainly composed of galacturonic acid and apiose (apiogalacturonans). Furthermore, sulfated galactans have been detected in some species. Recently, arabinogalactan-proteins (AGPs), highly glycosylated proteins of the cell wall of land plants, have been isolated for the first time from a seagrass of the baltic sea. Obviously, seagrass cell walls are characterized by new combinations of structural polysaccharide and glycoprotein elements known from macroalgae and angiosperm land plants. In this review, current knowledge on cell walls of seagrasses is summarized and suggestions for future investigations are given.

The article analyses regulatory reforms in the EU to the capital buffers for mitigating risks associated with institutions' systemic importance in the Capital Requirements Directive (CRD). The Directive includes a buffer for other relevant institutions (O-SIIs) and limits its size to a general cap and a specific cap for subsidiaries. However, the specific subsidiary cap may limit national authorities' ability to set a sufficient buffer for domestic institutions that are members of European banking groups to cover risks to the domestic market. It also may lead to a situation where two institutions of similar systemic importance could be subject to different O SII buffer rates because their owners are of different systemic importance and have different O-SII buffer rates in different EU jurisdictions. The amended CRD V increases the general and subsidiary cap for the O-SII reserve by one percentage point. However, the cap for subsidiary institutions remained in force, which limits the setting of capital buffers, especially for banking sectors with significant foreign ownership. These include mainly countries of the former Soviet-aligned Eastern Bloc. This paper outlines shortcomings of the subsidiary cap, argues for a revision of it to ensure level playing field in these capital buffers and quantifies the impact of the subsidiary cap according to the CRD IV and CRD V on the capital requirement applied to the Czech banking sector.

Despite rapid improvements in efficiency, long‐term stability remains a challenge limiting the future up‐scaling of perovskite solar cells (PSCs). Although several approaches have been developed to improve the stability of PSCs, applying ammonium passivation materials in bilayer configuration PSCs has drawn intensive research interest due to the potential of simultaneously improving long‐term stability and boosting power conversion efficiency (PCE). This review focuses on the recent advances of improving n‐i‐p PSCs photovoltaic performance by employing ammonium halide‐based molecular modulators. The first section briefly summarizes the challenges of perovskite materials by introducing the degradation mechanisms associated with the hygroscopic nature and ion migration issues. Then, recent reports regarding the roles of overlayers formed from ammonium‐based passivation agents are discussed on the basis of ligand and halide effects. This includes both the formation of 2D perovskite films as well as purely organic passivating layers. Finally, the last section provides future perspectives on the use of organic ammonium halides within bilayer‐architecture PSCs to improve the photovoltaic performances. Overall, this review provides a roadmap on current demands and future research directions of molecular modulators to address the critical limitations of PSCs, to mitigate the major barriers on the pathway toward future up‐scaling applications. Passivating the defects and preventing the degradation of metal halide perovskites by humidity continues to pose a big challenge to the vast scientific community developing this promising new light harvesting material. In this review, recent advances and prospects employing organic ammonium halide‐based passivation materials that attempt to suppress such issues in n–i–p architecture perovskite solar cells are discussed.

The paper describes the mechanism of overlapping lever-age ratio requirement and macroprudential capital buffers and as-sociated implications for the resilience of the banking sector. It ex-amines to what extent capital buffers can be usable to absorb lossesin the case of the Czech banking sector and what impact this mayhave on the lending capacity of the real economy. The non-usabilityportion of capital buffers in the Czech banking sector amounts toCZK 27 billion (i.e. 24% of the combined capital buffer). The lend-ing potential of the capital buffer decreases by CZK 630 billion toCZK 1.6 trillion due to overlaps under otherwise equal conditions.The results indicate that the leverage ratio requirement may preventthe capital buffers from being fully effective and can reduce createdmacroprudential space.

A preliminary study suggests that intestinal-wall assessment by means of noninvasive multispectral optoacoustic tomography may distinguish remission from active disease in patients with Crohn’s disease. To the Editor: In chronic inflammatory diseases, uncontrolled inflammation is associated with increased rates of hospitalization, complications, and death. Because of the potential severity of these conditions, there is an increased demand for new diagnostic approaches. 1 , 2 Multispectral optoacoustic tomography (MSOT) is a new imaging technique that permits the noninvasive quantification of hemoglobin-dependent tissue perfusion and oxygenation as surrogates of inflammation. 3 This approach uses the excitation of short-pulsed laser light with near-infrared wavelengths to induce the photoacoustic effect in targeted tissues, which results in detectable sound waves induced by thermoelastic expansion. In this single-center, cross-sectional diagnostic study (ClinicalTrials.gov number, NCT02622139), . . .

Simple fluoride salts are theoretically convenient reagents for carbon-fluorine bond formation. In practice, they are often insoluble in the solvents that dissolve their reaction partners. Pupo et al. developed urea-based catalysts that make fluoride soluble through hydrogen bonding. Moreover, their chiral substituents bias the reaction toward one of two mirror image products of C–F bond formation. This strategy should be applicable to the asymmetric addition of other salts, too. Science , this issue p. 638 A hydrogen bonding catalyst renders fluoride soluble and then guides it to form a C–F bond enantioselectively. Common anionic nucleophiles such as those derived from inorganic salts have not been used for enantioselective catalysis because of their insolubility. Here, we report that merging hydrogen bonding and phase-transfer catalysis provides an effective mode of activation for nucleophiles that are insoluble in organic solvents. This catalytic manifold relies on hydrogen bonding complexation to render nucleophiles soluble and reactive, while simultaneously inducing asymmetry in the ensuing transformation. We demonstrate the concept using a chiral bis-urea catalyst to form a tridentate hydrogen bonding complex with fluoride from its cesium salt, thereby enabling highly efficient enantioselective ring opening of episulfonium ion. This fluorination method is synthetically valuable considering the scarcity of alternative protocols and points the way to wider application of the catalytic approach with diverse anionic nucleophiles.

ObjectivesWe compared the interobserver agreement for the recently introduced contrast-enhanced ultrasound (CEUS)-based algorithm CEUS-LI-RADS (Liver Imaging Reporting and Data System) versus the well-established magnetic resonance imaging (MRI)-LI-RADS for non-invasive diagnosis of hepatocellular carcinoma (HCC) in high-risk patients.MethodsFocal liver lesions in 50 high-risk patients (mean age 66.2 ± 11.8 years; 39 male) were assessed retrospectively with CEUS and MRI. Two independent observers reviewed CEUS and MRI examinations, separately, classifying observations according to CEUS-LI-RADSv.2016 and MRI-LI-RADSv.2014. Interobserver agreement was assessed with Cohen’s kappa.ResultsForty-three lesions were HCCs; two were intrahepatic cholangiocarcinomas; five were benign lesions. Arterial phase hyperenhancement was perceived less frequently with CEUS than with MRI (37/50 / 38/50 lesions = 74%/78% [CEUS; observer 1/observer 2] versus 46/50 / 44/50 lesions = 92%/88% [MRI; observer 1/observer 2]). Washout appearance was observed in 34/50 / 20/50 lesions = 68%/40% with CEUS and 31/50 / 31/50 lesions = 62%/62%) with MRI. Interobserver agreement was moderate for arterial hyperenhancement (ĸ = 0.511/0.565 [CEUS/MRI]) and “washout” (ĸ = 0.490/0.582 [CEUS/MRI]), fair for CEUS-LI-RADS category (ĸ = 0.309) and substantial for MRI-LI-RADS category (ĸ = 0.609). Intermodality agreement was fair for arterial hyperenhancement (ĸ = 0.329), slight to fair for “washout” (ĸ = 0.202) and LI-RADS category (ĸ = 0.218)ConclusionInterobserver agreement is substantial for MRI-LI-RADS and only fair for CEUS-LI-RADS. This is mostly because interobserver agreement in the perception of washout appearance is better in MRI than in CEUS. Further refinement of the LI-RADS algorithms and increasing education and practice may be necessary to improve the concordance between CEUS and MRI for the final LI-RADS categorization.Key Points• CEUS-LI-RADS and MRI-LIRADS enable standardized non-invasive diagnosis of HCC in high-risk patients.• With CEUS, interobserver agreement is better for arterial hyperenhancement than for “washout”.• Interobserver agreement for major features is moderate for both CEUS and MRI.• Interobserver agreement for LI-RADS category is substantial for MRI, and fair for CEUS.• Interobserver-agreement for CEUS-LI-RADS will presumably improve with ongoing use of the algorithm.

Basel III introduced unweighted capital standard and new regulatory liquidity standards to complement the revised risk-weighted capital requirements. This change in banking sector regulation raised questions on how the capital and liquidity requirements interact and how they should be jointly treated. In the paper, we assess how a regulatory and a subsequent economic shock, and banks’ subsequent response to it, affects compliance with the four regulatory requirements. We find that the capital and liquidity requirements can act as both, substitutes and complements, depending on the adjustment strategy banks choose to react to these shocks. We assert that to be able to properly calibrate macroprudential policy measures such as the counter-cyclical capital buffer, it is vital for macroprudential authorities to look at the initial levels of the other required ratios as well as to monitor banks’ subsequent response.

Background The polyphyletic group of seagrasses shows an evolutionary history from early monocotyledonous land plants to the marine environment. Seagrasses form important coastal ecosystems worldwide and large amounts of seagrass detritus washed on beaches might also be valuable bioeconomical resources. Despite this importance and potential, little is known about adaptation of these angiosperms to the marine environment and their cell walls. Results We investigated polysaccharide composition of nine seagrass species from the Mediterranean, Red Sea and eastern Indian Ocean. Sequential extraction revealed a similar seagrass cell wall polysaccharide composition to terrestrial angiosperms: arabinogalactans, pectins and different hemicelluloses, especially xylans and/or xyloglucans. However, the pectic fractions were characterized by the monosaccharide apiose, suggesting unusual apiogalacturonans are a common feature of seagrass cell walls. Detailed analyses of four representative species identified differences between organs and species in their constituent monosaccharide composition and lignin content and structure. Rhizomes were richer in glucosyl units compared to leaves and roots. Enhalus had high apiosyl and arabinosyl abundance, while two Australian species of Amphibolis and Posidonia , were characterized by high amounts of xylosyl residues. Interestingly, the latter two species contained appreciable amounts of lignin, especially in roots and rhizomes whereas Zostera and Enhalus were lignin-free. Lignin structure in Amphibolis was characterized by a higher syringyl content compared to that of Posidonia . Conclusions Our investigations give a first comprehensive overview on cell wall composition across seagrass families, which will help understanding adaptation to a marine environment in the evolutionary context and evaluating the potential of seagrass in biorefinery incentives.