Enhancing the Activity of a Carbon Nitride Photocatalyst by Constructing a Triazine-Heptazine Homojunction.

Establishing homojunctions at the molecular level between different but physicochemically similar phases belonging to the same family of materials is an effective approach to promoting the photocatalytic activity of polymeric carbon nitride (CN) materials. Here, we prepared a CN material with a uniform distribution of homojunctions by combining two synthetic strategies: supramolecular assemblies as the precursor and molten salt as the medium. We designed porous CN rods with triazine-heptazine homojunctions (THCNs) using a melem supramolecular aggregate (Me) and melamine as the precursors and a KCl/LiBr salt mixture as the liquid reaction medium. The triazine/heptazine ratio is controlled by varying the relative amounts of the chosen precursors, and the molten salt treatment enhances the structural order of the interplanar packing units for the THCN skeleton, leading to rapid charge migration. The resulting built-in electric field induced by the triazine-heptazine homojunction enhances photogenerated charge separation; the optimal THCN catalyst exhibits an excellent H2 evolution rate via photocatalytic water splitting, which is ∼24 times as high as that of reference bulk CN, with long-term stability.

Usefulness of current sgRNA design guidelines and in vitro cleavage assays for plant CRISPR/Cas genome editing: a case targeting the polyphenol oxidase gene family in eggplant (Solanum melongena L.).

The advent of genome editing platforms such as the CRISPR/Cas9 system ushers an unprecedented speed in the development of new crop varieties that can withstand the agricultural challenges of the 21st century. The CRISPR/Cas9 system depends on the specificity of engineered single guide RNAs (sgRNAs). However, sgRNA design in plants can be challenging due to the multitude of design tools to choose from, many of which use guidelines that are based on animal experiments yet allow the use of plant genomes. Upon choosing sgRNAs, it is also unclear whether an in vitro assay is needed to validate the targeting efficiency of a particular sgRNA before in vivo delivery of the CRISPR/Cas9 system. Here, we demonstrate the in vitro and in vivo activity of four different sgRNAs that we selected based on their ability to target multiple members of the eggplant polyphenol oxidase gene family. Some sgRNAs that have high in vitro cleavage activity did not produce edits in vivo, suggesting that an in vitro assay may not be a reliable basis to predict sgRNAs with highly efficient in vivo cleavage activity. Further analysis of our sgRNAs using other design algorithms suggest that plant-validated criteria such as the presence of necessary secondary structures and appropriate base-pairing may be the reason for the discrepancy between our observed in vitro and in vivo cleavage efficiencies. However, recent reports and our data suggests that there is no guaranteed way to ensure the in vivo cleavage of chosen sgRNAs.

Developing extended visible light responsive polymeric carbon nitrides for photocatalytic and photoelectrocatalytic applications.

Polymeric carbon nitride (CN) has emerged as an attractive material for photocatalysis and photoelectronic devices. However, the synthesis of porous CNs with controlled structural and optical properties remains a challenge, and processable CN precursors are still highly sought after for fabricating homogenous CN layers strongly bound to a given substrate. Here, we report a general method to synthesize highly dispersed porous CN materials that show excellent photocatalytic activity for the hydrogen evolution reaction and good performance as photoanodes in photoelectrochemical cells (PEC): first, supramolecular assemblies of melem and melamine in ethylene glycol and water are prepared using a hydrothermal process. These precursors are then calcined to yield a water-dispersible CN photocatalyst that exhibits beneficial charge separation under illumination, extended visible-light response attributed to carbon doping, and a large number of free amine groups that act as preferential sites for a Pt cocatalyst. The optimized CN exhibits state-of-the-art HER rates up to 23.1 mmol h-1 g-1, with an AQE of 19.2% at 395 nm. This unique synthetic route enables the formation of a homogeneous precursor paste for substrate casting; consequently, the CN photoanode exhibits a low onset potential, a high photocurrent density and good stability after calcination.

Supramolecular organization of melem for the synthesis of photoactive porous carbon nitride rods.

Intrinsic defects and structural properties are two main factors influencing the photocatalytic performance of carbon nitride (CN) materials. Here, photoactive porous CN rods are fabricated through the thermal condensation of melem-based hexagonal supramolecular assemblies. To overcome the poor solubility of melem, we exfoliate the bulk melem using hydrochloric acid. The latter allows good dispersibility of the monomer in an aqueous medium, leading to the formation of H-bond bridged supramolecular assembly with good regularity in both size and rod-like morphology. After thermal condensation, a well-ordered structure of porous CN rods with fewer defects due to the high thermal stability of the melem-based supramolecular assembly is obtained. The new CN materials have a high specific surface area, good light-harvesting properties, and enhanced charge separation and migration. The optimal CN material exhibits excellent photocatalytic activity and durability towards hydrogen evolution reaction (HER) and CO2 reduction reaction (CO2RR, with good selectivity).

Association of Secukinumab Treatment With Tuberculosis Reactivation in Patients With Psoriasis, Psoriatic Arthritis, or Ankylosing Spondylitis.

Importance: Approximately one-quarter of the global population have latent tuberculosis infection (LTBI), and tuberculosis (TB) is accountable for more than 1.5 million deaths annually. Methotrexate, cyclosporine, and tumor necrosis factor inhibitors may be associated with increased risk of TB and LTBI reactivation, although data are limited on the risks of TB with use of newer biologics. Objective: To assess the association of secukinumab with reporting of active TB development, TB reactivation, and LTBI activation as an adverse event (AE) in patients with psoriasis, psoriatic arthritis, or ankylosing spondylitis. Design, Setting, and Participants: This pooled cohort study pooled data from 28 clinical trials of secukinumab used in psoriasis (17 phase 3 or 3b and 2 phase 4 trials), psoriatic arthritis (5 phase 3 trials), and ankylosing spondylitis (4 phase 3 trials). A search of the Novartis Secukinumab Compound Pool Database was conducted for the 28 trials. All trial participants who had received at least 1 approved subcutaneous dose of secukinumab (150 mg or 300 mg) were included. Before randomization in these trials, patients underwent screening for TB. Patients with active TB were excluded, and patients with LTBI were treated according to local guidelines. Data were analyzed from the start of treatment in the individual studies through December 25, 2018. Main Outcomes and Measures: Reporting of active TB or LTBI as an AE over a 5-year period using exposure-adjusted incidence rates (EAIR; incidence rates per 100 patient-years). Results: A total of 12 319 patients were included, of whom 8819 patients had psoriasis (71.6%; 5930 men [67.2%]; mean [SD] age, of 44.9 [13.5] years), 2523 had psoriatic arthritis (20.5%; 1323 women [52.4%]; mean [SD] age, 48.8 [12.1] years), and 977 had ankylosing spondylitis (7.3%; 658 men [67.3%]; mean [SD] age, 42.3 [11.9] years). In the total population, 684 patients (5.6%) had tested positive for LTBI at screening. Over 5 years, LTBI as an AE during secukinumab treatment was reported in 13 patients (0.1% of 12 319). Of these 13 patients, 6 had a prior positive LTBI test result, and 7 were newly diagnosed as having LTBI. Four of the 7 patients had psoriasis (EAIR, 0.03; 95% CI, 0.01-0.07), 1 had psoriatic arthritis (EAIR, 0.02; 95% CI, 0.00-0.11), and 2 had ankylosing spondylitis (EAIR, 0.08; 95% CI, 0.01-0.28). No cases of active TB were reported. Conclusions and Relevance: This study found that LTBI reported as an AE after secukinumab treatment was uncommon and appeared to support the use of secukinumab in chronic systemic inflammatory conditions.

Seasonal and spatial occurrence and distribution of atmospheric polycyclic aromatic hydrocarbons (PAHs) in rural and urban areas of the North Chinese Plain.

Passive air sampling (PAS) was employed to study the occurrence of gaseous and particle-bound PAHs in the North Chinese Plain. The averaged concentrations of gaseous and particle-bound PAHs were 485+/-209 ng/m(3) and 267+/-161 ng/m(3), respectively. The PAHs concentrations at urban sites were generally higher than those at rural ones with ratios <1.5 in spring, summer and fall, but differences between them were not significant for the wintertime and annually averaged concentrations. This urban-rural distribution pattern was related to the PAHs emission sources. PAHs spatial variation can be partially (49%) explained by emission with a simple linear regression method. Both the gaseous and particle-bound PAHs were highest in winter and lowest in summer, with winter/summer ratios of 1.8 and 8, respectively. Emission strength was the most important factor for the seasonality.