[Simultaneous determination of six benzodiazepine sedatives residue in aquatic products by high performance liquid chromatography-triple quadrupole mass spectrometry].

Objective: To establish a method for the simultaneous determination of 6 benzodiazepine sedatives residue in aquatic products by high performance liquid chromatography-triple quadrupole mass spectrometry.

Methods: The samples were extracted with acetonitrile and purified by C_(18 )solid phase extraction column. The sample solution was separated by Waters ACQUITY UPLC BEH C_(18 )column(2.

Comparative Investigation of the Microstructure of MgCl Aqueous Solutions Using Different X-ray Scattering Sources, Raman Spectroscopy, and Atomistic Simulations.

Aqueous solutions of magnesium chloride (MgCl(aq)) are often used to test advances in the theory of electrolyte solutions because they are considered an ideal strong 2:1 electrolyte. However, there is evidence that some ion association occurs in these solutions, even at low concentrations. Even a small ion-pairing constant can have a significant impact on the chemical speciation of ions, so it is important to determine whether ion pairing actually occurs.

Local Structure in α-BIMEVOXes (ME = Ge, Sn).

The BIMEVOXes are among the best oxide ion conductors at low and intermediate temperatures. Their high conductivity is associated with local defect structure. In this work, the local structures of two BIMEVOX compositions, BiVGeO and BiVSnO, are examined using total neutron and X-ray scattering methods, with both compositions exhibiting the ordered α-phase at 25 °C and the disordered γ-phase at 700 °C.

Grain Size Effects in Mn-Modified 0.67BiFeO-0.33BaTiO Ceramics.

Grain size can have significant effects on the properties of electroceramics for dielectric, piezoelectric, and ferroelectric applications. Here, we systematically investigate the effect of grain size on the structure and properties of Mn-modified 0.67BiFeO-0.

Non-linear dose-response relation between urinary levels of nicotine and its metabolites and cognitive impairment among an elderly population in China.

Background: Active smoking and exposure to environmental tobacco smoke may be related to cognitive function decline. We assessed the associations of urinary levels of nicotine and its metabolites with cognitive function.

Methods: A total of 553 elder adults at high risk of cognitive impairment and 2212 gender- and age-matched individuals at low risk of cognitive impairment were selected at a ratio of 1: 4 from the remained individuals (n = 6771) who completed the baseline survey of the Shenzhen Ageing-Related Disorder Cohort, after excluding those with either Alzheimer's disease, Parkinson's syndrome or stroke as well as those with missing data on variables (including active and passive smoking status, Mini-Cog score).

Terahertz Reading of Ferroelectric Domain Wall Dielectric Switching.

Ferroelectric domain walls (DWs) are important nanoscale interfaces between two domains. It is widely accepted that ferroelectric domain walls work idly at terahertz (THz) frequencies, consequently discouraging efforts to engineer the domain walls to create new applications that utilize THz radiation. However, the present work clearly demonstrates the activity of domain walls at THz frequencies in a lead-free Aurivillius phase ferroelectric ceramic, CaRbCeBiNbO, examined using THz-time-domain spectroscopy (THz-TDS).

Quantifications of saxitoxin concentrations in bivalves by high performance liquid chromatography-tandem mass spectrometry with the purification of immunoaffinity column.

In this study, saxitoxin (STX) immunoaffinity column (IAC) solid phase extraction (SPE) technology was used to extract and purify STX in bivalve aquatic products. By optimizing the conditions of sample pretreatment, the method of detecting STX in bivalve aquatic products had been established by high performance liquid chromatograph-tandem mass spectrometry (LC-MS/MS) based on the cleanup of SPE with immunoaffinity interaction mechanism. The phosphate buffer solution (PBS) was used to extract STX in bivalves.

Preparation of an Anti-Aggregation Silica/Zinc/Graphene Oxide Nanocomposite with Enhanced Adsorption Capacity.

Nanomaterials play a significant role in adsorption treatment of dye wastewater, but irreversible aggregation of nanoparticles poses a significant problem. In this work, nanomesoporous zinc-doped silicate (NMSZ) was prepared by an in situ method. To prevent agglomeration, NMSZ was covalently bonded to graphene oxide (GO) sheets to form a nano-silica/zinc/graphene oxide composite (GO-NMSZ), aimed at removal of cationic dye methylene blue (MB).

Tetrodotoxin poisoning caused by Goby fish consumption in southeast China: a retrospective case series analysis.

Objectives: To investigate an unusual outbreak of tetrodotoxin poisoning in Leizhou, southeast China, a case series analysis was conducted to identify the source of illness.

Methods: A total of 22 individuals experienced symptoms of poisoning, including tongue numbness, dizziness, nausea and limb numbness and weakness. Two toxic species, Amoya caninus and Yongeichthys nebulosus, were morphologically identified from the batches of gobies consumed by the patients.

Importance of the ionic nature of ionic liquids in affecting enzyme performance.

The activity and stability of mushroom tyrosinase were studied in ionic liquid (IL)-containing aqueous systems. The effect of three ILs ([BMIm][PF(6)], [BMIm][BF(4)]), and [BMIm][MeSO(4)], where [BMIm] = 1-butyl-3-methylimidazolium) and their inorganic salts (KMeSO(4), KPF(6), and NaBF(4)) on the enzyme performance was investigated by comparing the kinetic (such as K(m), V(max), optimal pH and temperature, and activation energy) and thermostability parameters (including half-lives, deactivation constants, activation energies for enzyme deactivation, DeltaG*, DeltaH*, and DeltaS*) of the enzyme in the absence and presence of the ILs and their anions. Both the three ILs and their inorganic salts were able to trigger enzyme activation.

Tyrosinase activity in ionic liquids.

Activity of mushroom tyrosinase was studied in three ionic liquids, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF(6)]), 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF(4)]) and 1-butyl-3-methylimidazolium methylsulfate ([BMIm][MeSO(4)]), and was compared to that in chloroform. Kinetic parameters of the enzyme were determined and the results indicate that the enzyme in ionic liquids basically follows the same catalytic mechanism as in water, and that the ionic liquids may affect the enzyme activity by direct interacting with the enzyme and thus hindering the E-S binding due to their high hydrophilicity and polarity.