Construction of covalent organic framework nanozymes with photo-enhanced hydrolase activities for colorimetric sensing of organophosphorus nerve agents.

Construction of covalent organic frameworks (COFs)-based nanozymes is of great importance for the extensive applications in catalysis and sensing fields. In this work, a two-dimensional COF (DAFB-DCTP COF) was fabricated via Knoevenagel condensation reaction. The integration of catalytically active sites of pyridine groups into the donor-acceptor (D-A) conjugated skeleton endows DAFB-DCTP COF with both hydrolytic and photosensitive properties. The DAFB-DCTP COF can be utilized as an artificial enzyme with selective and photo-enhanced catalytic efficiency, facilitating its application in photocatalytic degradation of hydrolase substrates (p-nitrophenyl acetate, pNPA) by nucleophilic reaction and further realizing colorimetric detection of the nanozyme inhibitor of organophosphorus nerve agent (diethyl cyanophosphonate, DCNP). The distinct color changes could be distinguished by naked eyes even at a low DCNP concentration, and the versatile smartphone analysis featured with reliability and simplicity. For the first time, the COFs' intrinsic hydrolase activity depending on their structural characteristics was investigated in synergy with the photosensitive performance originating from their photoelectric features. The present contribution provides a promising direction towards construction of colorimetric sensing platform based on the regulation of COFs' non-oxidoreductase activity under visible light irradiation.

Association of SGLT2 Inhibitors With Risk of Atrial Fibrillation and Stroke in Patients With and Without Type 2 Diabetes: A Systemic Review and Meta-Analysis of Randomized Controlled Trials.

ABSTRACT: Sodium-glucose cotransporter 2 (SGLT2) inhibitors have well-documented effects on reducing hospitalization for heart failure and cardiovascular mortality, although the effect on atrial fibrillation (AF) has not been comprehensively investigated. Therefore, we performed a meta-analysis to assess the association between SGLT2 inhibitors and AF risk by systematically searching PubMed, Embase, and ClinicalTrials.gov. Two investigators independently identified randomized controlled trials, which compared SGLT2 inhibitors with control in patients with type 2 diabetes, heart failure, or chronic kidney disease. Primary outcomes were incident AF and stroke. We included 20 randomized trials involving 63,604 patients. The SGLT2 inhibitors used were dapagliflozin (7 studies, 28,834 patients), canagliflozin (7 studies, 17,440 patients), empagliflozin (5 studies, 9082 patients), and ertugliflozin (1 study, 8246 patients). Follow-up ranged from 24 weeks to 202 weeks. SGLT2 inhibitors treatment was associated with a significant attenuation in the risk of incident AF (odds ratio = 0.82; 95% confidence interval, 0.72-0.93; P = 0.002) compared with control. No significant difference in stroke between SGLT2 inhibitors and control groups was found (odds ratio = 0.99; 95% confidence interval, 0.85-1.15; P = 0.908). This present meta-analysis indicates that SGLT2 inhibitors are associated with a lower risk of incident AF and do not significantly affect stroke risk for patients with and without type 2 diabetes.

Rapid and sensitive detection of Mycobacterium tuberculosis based on strand displacement amplification and magnetic beads.

Tuberculosis is one of the main infectious diseases threatening public health, and the development of simple, rapid, and cost-saving methods for tuberculosis diagnosis is of profound importance for tuberculosis prevention and treatment. The bacterium Mycobacterium tuberculosis (MTB) is the pathogen that causes tuberculosis, and assaying for MTB is the only criterion for tuberculosis diagnosis. A new enzyme-free method based on strand displacement amplification and magnetic beads was developed for simple, rapid, and cost-saving MTB detection. Under optimum conditions, a good linear relationship could be observed between fluorescence and MTB specific DNA concentration ranging from 0.05 to 150 nM with a correlation coefficient of 0.993 (n = 8) and a detection limit of 47 pM (3σ/K). The present method also distinguished a one base mismatch from MTB specific DNA, showing great promise for MTB genome single base polymorphism analysis. MTB specific DNA content in polymerase chain reaction samples was successfully detected using the new method, and recoveries were 97.8-100.8%, indicating that the present method had high accuracy and shows good potential for the early diagnosis of tuberculosis.

The Invasion of Coastal Areas in South China by Ipomoea cairica May Be Accelerated by the Ecotype Being More Locally Adapted to Salt Stress.

Local adaptation and phenotypic plasticity are two alternative mechanisms used by invasive plants for range expansion. We conducted a series of experiments to investigate the role of these mechanisms in the recent expansion of the invasive Ipomoea cairica from non-saline to salt-stressed coastal habitats. A comparison of the plant's photosynthetic traits and construction costs across habitats was conducted through a field survey. Meanwhile, a full factorial greenhouse experiment was conducted with two ecotypes (non-saline and coastal) of I. cairica and two salinity gradients (water and 4 g L-1 NaCl solution) to evaluate the roles of the two strategies by comparing their main traits. The results revealed that the construction cost and Amax of I. cairica did not change with the habitat type. The ecotype and saline treatments, however, significantly influenced the plant growth. The non-saline ecotype (NE) generally showed higher or equal plasticity of biomass-allocation and functional traits compared to the coastal ecotype (CE). However, the fitness and biomass of the NE significantly decreased with salinity, whereas those aspects of the CE did not change. Our results indicate that the recent expansion of I. cairica into coastal areas may be accelerated by the local adaptation of the CE to salt stress. Additionally, in South China, the CE will most likely evolve adaptations to both saline and non-saline environments, which will further broaden the invasion range of I. cairica in the future.

Poly[[tetraaqua-bis(µ(3)-1H-benzimidazole-5,6-dicarboxyl-ato)dicobalt(II)] trihydrate].

The title complex, {[Co(2)(C(9)H(4)N(2)O(4))(2)(H(2)O)(4)]·3H(2)O}(n), was synthesized hydro-thermally. The unique Co(II) ion is coordin-ated in a distorted octa-hedral coordination environment by two water mol-ecules and three symmetry-related 1H-benzimid-azole-5,6-dicarboxyl-ate (Hbidc) ligands. The Hbidc ligands coordinate via a bis-chelating and mono-chelating carboxyl-ate group and by an imidazole group N atom, bridging the Co(II) ions and forming an extended two-dimensional structure in the ab plane. In the crystal structure, inter-molecular N-H⋯O and O-H⋯O hydrogen bonds connect complex and solvent water mol-ecules, forming a three-dimensional supermolecular network. One of the solvent water mol-ecules lies on a twofold rotation axis.