Development and validation of a sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry method for quantitative analysis of bambermycin in livestock and aquatic products: Implications for food safety control and regulatory enforcement.

A sensitive and accurate analytical method was developed and validated to detect bambermycin, a commonly used antibiotic in animal feed and livestock. The presence of bambermycin residues in food products can pose health risks to consumers, emphasizing the need for a sensitive and accurate analytical method. A reversed-phase analytical column was utilized with a mobile phase comprising 0.

Nanoscale Control of Amyloid Self-Assembly Using Protein Phase Transfer by Host-Guest Chemistry.

Amyloid fibrils have recently been highlighted for their diverse applications as functional nanomaterials in modern chemistry. However, tight control to obtain a targeted fibril length with low heterogeneity has not been achieved because of the complicated nature of amyloid fibrillation. Herein, we demonstrate that fibril assemblies can be homogeneously manipulated with desired lengths from ~40 nm to ~10 μm by a phase transfer of amyloid proteins based on host-guest chemistry.

Distinct Fragmentation Pathways of Anticancer Drugs Induced by Charge-Carrying Cations in the Gas Phase.

With the growth of the pharmaceutical industry, structural elucidation of drugs and derivatives using tandem mass spectrometry (MS) has become essential for drug development and pharmacokinetics studies because of its high sensitivity and low sample requirement. Thus, research seeking to understand fundamental relationships between fragmentation patterns and precursor ion structures in the gas phase has gained attention. In this study, we investigate the fragmentation of the widely used anticancer drugs, doxorubicin (DOX), vinblastine (VBL), and vinorelbine (VRL), complexed by a singly charged proton or alkali metal ion (Li, Na, K) in the gas phase.

Structural Characterization of Anticancer Drug Paclitaxel and Its Metabolites Using Ion Mobility Mass Spectrometry and Tandem Mass Spectrometry.

Paclitaxel (PTX) is a popular anticancer drug used in the treatment of various types of cancers. PTX is metabolized in the human liver by cytochrome P450 to two structural isomers, 3′-p-hydroxypaclitaxel (3p-OHP) and 6α-hydroxypaclitaxel (6α-OHP). Analyzing PTX and its two metabolites, 3p-OHP and 6α-OHP, is crucial for understanding general pharmacokinetics, drug activity, and drug resistance.

Effect of a second injection of botulinum toxin on lower facial contouring, as evaluated using 3-dimensional laser scanning.

Background: Botulinum toxin type A (BoNT-A) is widely used to improve the lower facial contour.

Objective: To determine the difference in the changes in the lower facial contour achieved with 1 and 2 sessions of BoNT-A injections using 3-dimensional (3D) laser scanning.

Materials And Methods: Twenty volunteers were randomly divided into 2 groups.

Fluorescence switch for silver ion detection utilizing dimerization of DNA-Ag nanoclusters.

A fluorescence switch that consists of DNA-templated silver nanoclusters (DNA-AgNCs) triggered by silver ion (Ag(+)) is developed to detect Ag(+). The mechanism of the fluorescence switching of DNA-AgNCs is investigated by fluorescence spectroscopy, circular dichroism spectroscopy, DNA hybridization assay and mass spectrometry. Ag(+) induces a dimeric structure of Cyt12-AgNCs by forming a bridge between two Cyt12-AgNCs, where Cyt12 is cytosine 12-mer; this dimer formation causes the fluorescence change of Cyt12-AgNCs from red to green.

Supramolecular inhibition of amyloid fibrillation by cucurbit[7]uril.

Amyloid fibrils are insoluble protein aggregates comprised of highly ordered β-sheet structures and they are involved in the pathology of amyloidoses, such as Alzheimer's disease. A supramolecular strategy is presented for inhibiting amyloid fibrillation by using cucurbit[7]uril (CB[7]). CB[7] prevents the fibrillation of insulin and β-amyloid by capturing phenylalanine (Phe) residues, which are crucial to the hydrophobic interactions formed during amyloid fibrillation.

DNA-templated silver nanoclusters as label-free, sensitive detection probes for potassium ions and nitric oxide.

DNA-templated silver nanoclusters (DNA-AgNCs) have emerged as promising materials for sensing, bio-labelling, and bio-imaging due to their fluorogenic properties. Using the 12 mer DNA with a cytosine-rich sequence, AgCNs have been formed successfully. Herein, we develop two different types of DNA-AgNC systems for the detection of potassium ions (K) and nitric oxide (NO) by utilizing the structural change of DNA or DNA template transformation.

Host-guest chemistry from solution to the gas phase: an essential role of direct interaction with water for high-affinity binding of cucurbit[n]urils.

An investigation of the host-guest chemistry of cucurbit[n]uril (CB[n], n = 6 and 7) with α,ω-alkyldiammonium guests (H2N(CH2)xNH2, x = 4, 6, 8, 10, and 12) both in solution and in the gas phase elucidates their intrinsic host-guest properties and the contribution of solvent water. Isothermal titration calorimetry and nuclear magnetic resonance measurements indicate that all alkyldiammonium cations have inclusion interactions with CB[n] except for the CB[7]-tetramethylenediamine complex in aqueous solution. The electrospray ionization of mixtures of CB[n] and the alkyldiammonium guests reflects their solution phase binding constants.