Layered double hydroxides (LDHs), also known as hydrotalcite-like materials or anionic clays, are an important class of layered materials. Various studies show that LDHs have a wide range of applications in industry, e.g., catalyst precursors, ion exchangers, adsorbents for environmental contaminants, and substrates for the immobilization of biological material. [1][2][3][4] However, for the purpose of developing novel innovative applications of LDHs as materials for chemical sensors, [5,6] clay-modified electrodes, [7,8] corrosion-resistant coatings, [9,10] membrane catalysis, or components in optical and magnetic devices, intensive studies have been conducted aimed at organizing LDH microcrystals into large uniformly aligned 2D arrays or films. Several methods have been employed to fabricate LDH films on different substrates thus far. For example, LDH microcrystals have been deposited on indium-doped SnO 2 coated glass, platinum disks, and gold electrode surfaces from colloidal suspensions in order to prepare LDH films for electrode modification by deposition [11,12] and Langmuir-Blodgett methods. [8] Most of the films obtained, however, were not oriented or uniformly aligned as it is hard to control the LDH crystallite orientation using these methods. Recently, new techniques have been reported for the fabrication of oriented LDH films. Pinnavaia and co-workers found that colloidal suspensions of LDHs obtained through hydrolysis of LDH/methoxide were able to form transparent and smooth films, [13] in which the LDH microcrystals were extremely well oriented. By employing ultrasonification, Jung and co-workers obtained a monolayer of LDH films with a high packing density and a preferred orientation with the c-axis perpendicular to the substrate surface (ab-face parallel). [14,15] However, this route did not allow control of the orientation of the LDH microcrystals with respect to the substrate plane because of the intrinsic propensity of the microcrystals to align in an orientation that leads to maximum faceto-face contact between the crystals and the substrate. In spite of the progress made during the last decade in research on LDH films and their crystal orientation, there has been no synthetic method for directly growing uniformly aligned LDH polycrystalline films from a substrate. Growing thin films directly from a substrate considerably improves the adherence and the mechanical stability of the resulting thin film, compared to colloidal-deposition techniques (for example, spin-coating, dip-coating, and screen-printing).[16] Therefore, the exploration of new approaches to fabricate oriented LDH films on substrates is of significant importance. Among the existing synthetic methods to fabricate inorganic films, hydrothermal synthesis shows high flexibility in terms of control of the structure and morphology of the resulting inorganic materials. It is also a well-known pathway for fabricating inorganic films with the desired micro-or nanostructure and controlled crystal orientation. Our group has recently repor...

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Shiga toxin (Stx) is the key virulent factor in Shiga toxin-producing Escherichia coli (STEC). To date, three Stx1 subtypes and seven Stx2 subtypes have been described in E. coli, which differed in receptor preference and toxin potency. Here, we identified a novel Stx2 subtype designated Stx2h in E. coli strains isolated from wild marmots in the Qinghai-Tibetan plateau, China. Stx2h shares 91.9% nucleic acid sequence identity and 92.9% amino acid identity to the nearest Stx2 subtype. The expression of Stx2h in type strain STEC299 was inducible by mitomycin C, and culture supernatant from STEC299 was cytotoxic to Vero cells. The Stx2h converting prophage was unique in terms of insertion site and genetic composition. Whole genome-based phylo- and patho-genomic analysis revealed STEC299 was closer to other pathotypes of E. coli than STEC, and possesses virulence factors from other pathotypes. Our finding enlarges the pool of Stx2 subtypes and highlights the extraordinary genomic plasticity of E. coli strains. As the emergence of new Shiga toxin genotypes and new Stx-producing pathotypes pose a great threat to the public health, Stx2h should be further included in E. coli molecular typing, and in epidemiological surveillance of E. coli infections.

Solar-driven carbonylation with CO2 replacing toxic CO as a C1 source is of considerable interest; however it remains a great challenge due to the inert CO2 molecule. Herein, we integrate cobalt single-site and ultrafine CuPd nanocluster catalysts into a porphyrin-based metal–organic framework to construct composite photocatalysts (Cu1Pd2) z @PCN-222­(Co) (z = 1.3, 2.0, and 3.0 nm). Upon visible light irradiation, excited porphyrin can concurrently transfer electrons to Co single sites and CuPd nanoclusters, providing the possibility for coupling CO2 photoreduction and Suzuki/Sonogashira reactions. This multicomponent synergy in (Cu1Pd2)1.3@PCN-222­(Co) can not only replace dangerous CO gas but also dramatically promote the photosynthesis of benzophenone in CO2 with over 90% yield and 97% selectivity under mild condition. Systematic investigations clearly decipher the function and collaboration among different components in these composite catalysts, highlighting a new insight into developing a sustainable protocol for carbonylation reactions by employing greenhouse gas CO2 as a C1 source.

in Wiley InterScience (www.interscience.wiley.com).Activated layered double hydroxides (LDHs) with high crystallinity, obtained by calcination/rehydration of LDH precursors synthesized by urea decomposition, have higher catalytic activity in acetone self-condensation and Knoevenagel reactions than less crystalline materials obtained from LDH precursors synthesized by titration coprecipitation. The activated LDHs possess both basic and acidic sites. High resolution transmission electron microscopy (HRTEM) confirms that the highly crystalline activated LDHs retain the lattice structure of the LDH precursors with lattice parameters a ¼ b ¼ 0.31 6 0.01 nm and a ¼ 60 6 28. An acid-base catalytic mechanism has been proposed to interpret the catalytic behavior based on the fact that acid-base hydroxyl group pairs on the activated LDH surface have a separation of 0.31 nm. It is proposed that the active sites are mainly located on the ordered array of hydroxyl sites on the basal surfaces rather than on the edges, as has been previously suggested.

Sample About 10,000 maternal deaths among 4.3 million live births over two decades Methods We analysed trends in the maternal mortality ratio (MMR) from 1997 through 2020, estimated absolute maternal deaths, and examined causes of maternal death using nationallyrepresentative data sources; partitioned UN-adjusted female (aged 15-49) deaths, live birth totals, based on the 2001-2014 Million Death Study cause of death data. Main outcome measures Maternal mortality burden and distribution of causes.

In situ Microstructure Control of Oriented Layered Double Hydroxide Monolayer Films with Curved Hexagonal Crystals as Superhydrophobic Materials. -NiAl-layered double hydroxide films are prepared by in situ crystallization on a porous anodic Al2O3/Al substrate from aqueous solutions of Ni(NO3)2, NH4NO3, and NH4OH (autoclave, 120°C, 36 h). The samples are characterized by XRD and SEM. The surface micro-/nanostructure of the films is easily controlled by crystallization temperature and time leading to layered double oxide films with novel physical and chemical properties for applications as superhydrophobic coating materials. -(CHEN, H.; ZHANG, F.; FU, S.; DUAN*, X.; Adv.

Shiga toxin-producing Escherichia coli (STEC) causes diarrhea and hemorrhagic colitis with life-threatening complications, such as hemolytic uremic syndrome. The aim of this study was to assess the molecular epidemiologic features of non-O157 STEC strains from different resources in China and illustrate the role of animal reservoirs or animal-derived foodstuffs in human STEC infections. A collection of 301 non-O157 STEC isolates from domestic and wild animals (i.e., cattle, goat, pig, yak, pika, and antelope), raw meats (i.e., beef, pork, mutton, chicken, and duck), diarrheal patients, and healthy carriers in different regions of China were selected in this study. Of the 301 analyzed STEC isolates, 67 serogroups, and 118 serotypes were identified; this included some predominant serogroups associated with human disease, such as O26, O45, O103, O111, and O121. Eighteen different combinations of stx subtypes were found. Eleven isolates carried the intimin gene eae, 93 isolates contained ehxA, and 73 isolates carried astA. The prevalence of other putative adhesion genes saa, paa, efa1, and toxB was 28.90% (87), 6.98% (21), 2.31% (7), and 1% (3), respectively. The phylogenetic distribution of isolates was analyzed by multilocus sequence typing (MLST). Ninety-four sequence types were assigned across the 301 isolates. A subset of isolates recovered from yak and pika residing in the similar wild environments, Qinghai-Tibetan plateau, showed similar genetic profiles and more tendencies to cluster together. Isolates from goat and mutton exhibited close genetic relatedness with those from human-derived isolates, providing evidence that transmission may have occurred locally within intraspecies or interspecies, and importantly, from animal reservoirs, or raw meats to humans. Comparing isolates in this study with highly virulent strains by MLST, along with serotyping and virulence profiles, it is conceivable that some of isolates from goat, yak, or raw meats may have potential to cause human diseases.