[Occurrence and Distribution of Potential Dangerous Biological Agents in Beijing Suburban Rivers].

Dangerous biological agents （DBAs） refer to microorganisms, toxins, and other biological substances that have the potential to cause significant harm to humans, animals, plants, and the environment. They are the primary target of the prevention and response in China's Biosafety Law, and it is of great importance to clarify the characteristics of DBAs in the Beijing suburban rivers for the insurance of the water safety in Beijing. The typical Beijing suburban rivers （Mangniu River, Chaohe River, and Baihe River） were selected, and the occurrence and distribution of DBAs concerning the molecular biology composition as the nucleic acid （antibiotic resistance genes, ARGs）, nucleic acid and proteins （viruses）, and intact cellular structures （pathogens） were determined based on the metagenomics.

Unlocking the potential of the 3-hydroxykynurenine/kynurenic acid ratio: a promising biomarker in adolescent major depressive disorder.

Metabolites disruptions in tryptophan (TRP) and kynurenine pathway (KP) are believed to disturb neurotransmitter homeostasis and contribute to depressive symptoms. This study aims to investigate serum levels of KP metabolites in adolescent major depressive disorder (AMDD), and examine their relationship with depression severities. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to analyze serum levels of TRP, kynurenic acid (KYNA), kynurenine (KYN), and 3-hydroxy-kynurenine (3-HK) in 143 AMDD participants and 98 healthy controls (HC).

[Effects of Nitrogen Speciation Transformation on Microbial Community Succession in Input Rivers of Miyun Reservoir].

The Miyun Reservoir is the major source of surface drinking water in Beijing. However, the total nitrogen (TN) concentrations in the Miyun Reservoir and inflowing rivers have recently been increasing. In this study, the Mangniu River, a typical inflow river in the upper reaches of the Miyun Reservoir, was selected as the study area to investigate the spatial distribution and transformation of various nitrogen forms from the perspective of microbial community composition and predicting function, aimimg at providing a scientific reference for nitrogen pollution control of the Miyun Reservoir.

Bile acid profiles in choledocholithiasis and their ability to predict common bile duct stone recurrence after endoscopic retrograde cholangiopancreatography treatment.

Background/purpose: This study aimed to explore the alteration of bile acid (BA) profiles in patients with choledocholithiasis (CDC) and construct a prediction model for evaluating the risk of common bile duct stone (CBDS) recurrence after endoscopic treatment.

Methods: A total of 320 patients (218 with CDC and 102 with nonneoplastic polyps) were enrolled. The serum BA profiles were compared between groups.

Rapid LC-MS/MS detection of different carbapenemase types in carbapenemase-producing Enterobacterales.

Klebsiella pneumoniae carbapenemase (KPC)-2, metallo-beta-lactamases (MBL), and oxacillinase (OXA)-48-like carbapenemases are considered the most important carbapenemases. In vitro studies have demonstrated that the carbapenemase activity of KPC-2 and MBL can be inhibited by 3-aminophenylboronic acid and ethylenediaminetetraacetic acid (EDTA), respectively. Understanding the carbapenemase types expressed in carbapenem-resistant Enterobacterales (CRE) is of great significance to clinical therapies.

Use of neomycin as a structured amino-containing side chain motif for phenanthroline-based G-quadruplex ligands and telomerase inhibitors.

In this paper, we report the synthesis of a phenanthroline and neomycin conjugate (7). Compound 7 binds to a human telomeric G-quadruplex (G1) with a higher affinity compared with its parent compounds (phenanthroline and neomycin), which is determined by several biophysical studies. Compound 7 shows good selectivity for G-quadruplex (G4) DNA over duplex DNA.

Optimization of a NH4PF6-enhanced, non-organic solvent, dual microextraction method for determination of phthalate metabolites in urine by high performance liquid chromatography.

In conventional ionic liquid-based dispersive liquid-liquid microextraction (IL-DLLME) procedures, most of the IL disperser remains in the aqueous phase resulting in low recovery for moderately and weakly polar analytes due to the "carry-over effect". Herein, we successfully developed a "NH4PF6-enhanced, non-organic solvent, dual microextraction" method (ANSDM) for pretreatment of phthalate (PAE) metabolites with weak to moderate polarity. This method utilized in situ reaction of NH4PF6 as an ion-exchange reagent and disperser to realize two microextractions after using [C8MIM]PF6 as an extraction solvent and [C4MIM]BF4 as a disperser for conventional DLLME.

[Virological impact of stalk region of neuraminidase in influenza A/Anhui/1/05 (H5N1) and A/Ohio/07/2009 (H1N1) viruses].

This study aims to investigate the virological impact of the stalk region and cysteine (C) in neuraminidase (NA) of influenza A/Anhui/1/05 (H5N1) and A/Ohio/07/2009 (H1N1) viruses. The NA of A/ Anhui/1/05 (H5N1), defined as AH N1, lacked 20 amino acids (including C, defined as s20) as compared with NA of A/Ohio/07/2009 (H1N1) (defined as 09N1). We deleted s20 of 09N1 to construct 09N1-s20, and inserted s20 into AH N1 to construct AH N1+s20.

Nitrogen enrichment in runoff sediments as affected by soil texture in Beijing mountain area.

Enrichment ratio (ER) is widely used in nonpoint source pollution models to estimate the nutrient loss associated with soil erosion. The objective of this study was to determine the ER of total nitrogen (ERN) in the sediments eroded from the typical soils with varying soil textures in Beijing mountain area. Each of the four soils was packed into a 40 by 30 by 15 cm soil pan and received 40-min simulated rainfalls at the intensity of 90 mm h(-1) on five slopes.