Enantioselective Recognition Mechanism of Ofloxacin via Cu(II)-Modulated DNA

The specific interactions of Cu²⁺ with self-complementary DNA sequences involving d­[G₄C₄(GC)₂G₄C₄], d­[(GC)₁₀], and d­[(AT)₁₀], as well as the chiral recognition mechanism of ofloxacin enantiomers via the Cu^II-modulated DNAs, were investigated using characterizations of circular dichroism, gel electrophoresis, FT-IR spectroscopy, UV melting measurement, electron paramagnetic resonance, and HPLC. The Cu^II-coordinated GC-rich DNAs exhibit amplified enantioselectivity toward the <i>S</i>-enantiomer of ofloxacin. Especially in the case of d­[G₄C₄(GC)₂G₄C₄], ofloxacin enantiomers intercalate into the two adjacent guanine bases through the minor groove mediated by Cu²⁺, which leads to a more favorable binding between <i>S</i>-ofloxacin and DNA. The highest ee value of ofloxacin enantiomers in the permeate after being adsorbed by the Cu^II–DNA complex is obtained as 49.2% in the <i>R</i>-enantiomer at the [Cu²⁺]/[base] molar ratio of 0.25, while at the [Cu²⁺]/[base] molar ratio of 0.05 the highest ee value of ofloxacin enantiomers in the retentate reaches 26.3% in the <i>S</i>-enantiomer. This work illustrates a novel promising route to construct DNA-based chiral selectors toward certain drug enantiomers through the programmable enantioselective recognition on the basis of DNA chirality and the specific binding of transition metal ions

Table_1_“Low-risk groups” deserve more attention than “high-risk groups” in imported COVID-19 cases.docx

ObjectiveTo estimate the optimal quarantine period for inbound travelers and identify key risk factors to provide scientific reference for emerging infectious diseases.MethodsA parametric survival analysis model was used to calculate the time interval between entry and first positive nucleic acid test of imported cases in Guangzhou, to identify the influencing factors. And the COVID-19 epidemic risk prediction model based on multiple risk factors among inbound travelers was constructed.ResultsThe approximate 95th percentile of the time interval was 14 days. Multivariate analysis found that the mean time interval for inbound travelers in entry/exit high-risk occupations was 29% shorter (OR 0.29, 95% CI 0.18–0.46, p ConclusionDifferent strata of imported cases can result in varying degrees of risk of indigenous outbreaks. “low-risk groups” with entry/exit low-risk occupations, fully vaccinated, or from Asia deserve more attention than “high-risk groups.”</p

Supplemental material for Analysis of Diethylstilbestrol Residues in Chicken Using Surface-Enhanced Raman Spectroscopy (SERS) Coupled with Multivariate Analysis

Supplemental material for Analysis of Diethylstilbestrol Residues in Chicken Using Surface-Enhanced Raman Spectroscopy (SERS) Coupled with Multivariate Analysis by Xiongfei Chen, Muhua Liu, Haichao Yuan, Shuanggen Huang, Jinjiang Tao and Jinhui Zhao in Applied Spectroscopy</p

A Highly Active N‑Doped Carbon Supported CoFe Alloy Catalyst for Hydroformylation of C₈ Olefins

The development of inexpensive and efficient Co-based heterogeneous catalysts for hydroformylation reactions remains an enormous challenge. In this paper, N-doped carbon supported CoFe bimetallic catalysts (CoFe/NC) are successfully synthesized through a simple thermal decomposition of a mixture of Co­(acac)2 and Fe­(acac)3, and melamine with activated carbon in N2 atmosphere. With the CoFe/NC-800 as the catalyst, hydroformylation of diisobutene proceeded smoothly in THF under 4 MPa syngas at 130 °C to obtain 92% conversion of diisobutene and 79.6% selectivity to isononyl aldehydes. Detailed studies revealed that the N-doped carbon supported FeCo alloy may be the active species in which nitrogen might act as ligand played an important role in improvement of catalytic performance of hydroformylation reactions. The present study provided meaningful insights into tuning the catalytic performance of non-noble metal heterogeneous catalysts for carbonylation reaction

Silver Nanomaterials Regulated by Structural Competition of G-/C-Rich Oligonucleotides

Silver nanomaterials with distinct fluorescent properties are synthesized with a series of G-rich/C-rich DNA templates, and the influence of DNA conformational structures on the size and the fluorescence of silver nanomaterials was investigated through varying the sequence composition and the ratio of complementary sequences, using CD, UV–vis, fluorescence spectroscopy, and TEM. It is intriguing to find out that G-rich templates at acidic conditions are capable of generating red emitters that are susceptible to the G-quadruplex structures associated with the number of 5′-terminal guanines. C-rich sequences can produce red silver clusters at either acidic or neutral conditions, and the emission is dramatically regulated by the number of 3′-end cytosines. It is the first time to report that double-stranded DNA templates can generate distinct fluorescent nanosilver modulated by the predominance among the structural competition of the Watson–Crick duplex, G-quadruplex, and i-motif. These results provide a promising pathway to prepare silver nanomaterials with desirable physicochemical properties through designing suitable DNA templates

Modulation of Charge Transport from Two-Dimensional Perovskites to Industrial Charge Transport Layers by the Organic Spacer-Dependent Exciton–Phonon Interactions

In the past decade, two-dimensional (2D) perovskite surface treatment has emerged as a promising strategy to improve the performance of three-dimensional (3D) perovskite solar cells (PSCs). However, systematic studies on the impact of organic spacers of 2D perovskites on charge transport in 2D/3D PSCs are still lacking. Here, using 2D perovskite film/C60 heterostructures with different organic spacers [butylamine (BA), phenylethylamine (PEA), and 3-fluorophenethylamine (m-F-PEA)], we systematically investigated the carrier diffusion and interfacial transfer process. Using a 2D perovskite film with a thickness of ∼7 nm, we observed subtle differences in electron transfer time between 2D perovskites and C60 layers, which can be attributed to limited thickness and similar electron coupling strength. However, with the thickness of 2D perovskite increasing, electron transfer efficiency in the (BA)2PbI4/C60 heterostructure exhibits the most rapid decrease due to poor carrier diffusion of (BA)2PbI4 caused by stronger exciton–phonon interactions compared to (PEA)2PbI4 and (m-F-PEA)2PbI4 in thickness-dependent charge transfer research. Meanwhile, the fill factor of 2D/3D PSC treated with BAI exhibits the most rapid decrease compared to PEAI- and m-F-PEAI-treated 2D/3D PSCs with the concentration increase of passivators. This study indicates that it is easier to enhance open-circuit voltages and minimize the decrease of fill factor by increasing the concentration of passivators in 2D/3D PSCs when using passivators with a rigid molecular structure

Additional file 3 of Couple-based collaborative management model of type 2 diabetes mellitus for community-dwelling older adults in China: protocol for a hybrid type 1 randomized controlled trial

Additional file 3. Evaluation of couple intervention. Evalutaion of patients and their spouses during intervention implementation

Additional file 2 of Couple-based collaborative management model of type 2 diabetes mellitus for community-dwelling older adults in China: protocol for a hybrid type 1 randomized controlled trial

Additional file 2. Activity planning demonstration. A demonstration of the intervention implemented on participants specific to each single day of the week

Additional file 1 of Couple-based collaborative management model of type 2 diabetes mellitus for community-dwelling older adults in China: protocol for a hybrid type 1 randomized controlled trial

Additional file 1. The SPIRIT reporting guidelines. The SPIRIT 2013 checklist our manuscript follows according to the recommendations on it

HI antibody dynamics in infected patients and vaccinated people.

<p>Note: Detection limitation (HI titer <20) is indicated by the dotted line. Error bar indicates ± standard deviation (SD) from different individual study subjects. * indicates significant differences (<i>P</i><0.01) between results of day 30 and day 180.</p