[Chemical Speciation, Influencing Factors, and Regression Model of Heavy Metals in Farmland of Typical Carbonate Area with High Geological Background, Southwest China].

The speciation of heavy metals in soil is an important factor determining their bioavailability and toxicity, and it is crucial for the scientific assessment of ecological risks posed by heavy metals in soils of typical carbonate areas with high geological background in southwest China. In order to investigate the distribution of speciation of heavy metals in soils of carbonate rock with high geological background, we selected a typical carbonate rock distribution area in Guizhou Province and used the second national soil survey plots as sampling units. A total of 309 topsoil samples were collected from farmland.

Heterogeneous chemistry of ozone with floor cleaning agent: Implications of secondary VOCs in the indoor environment.

Human daily activities such as cooking, and cleaning can affect the indoor air quality by releasing primary emitted volatile organic compounds (VOCs), as well as by the secondary product compounds formed through reactions with ozone (O) and hydroxyl radicals (OH). However, our knowledge about the formation processes of the secondary VOCs is still incomplete. We performed real-time measurements of primary VOCs released by commercial floor-cleaning detergent and the secondary product compounds formed by heterogeneous reaction of O with the constituents of the cleaning agent by use of high-resolution mass spectrometry.

The Effect of Human Occupancy on Indoor Air Quality through Real-Time Measurements of Key Pollutants.

The primarily emitted compounds by human presence, e.g., skin and volatile organic compounds (VOCs) in breath, can react with typical indoor air oxidants, ozone (O), and hydroxyl radicals (OH), leading to secondary organic compounds.

Daytime SO chemistry on ubiquitous urban surfaces as a source of organic sulfur compounds in ambient air.

The reactions of sulfur dioxide (SO) with surface-bound compounds on atmospheric aerosols lead to the formation of organic sulfur (OS) compounds, thereby affecting the air quality and climate. Here, we show that the heterogeneous reaction of SO with authentic urban grime under near-ultraviolet sunlight irradiation leads to a large suite of various organic compounds including OS released in the gas phase. Calculations indicate that at the core area of Guangzhou, building surface uptake of SO is 15 times larger than uptake of SO on aerosol surfaces, yielding ~20 ng m of OS that represents an important fraction of the observed OS compounds (60 to 200 ng m) in ambient aerosols of Chinese megacities.

Unveiling the pH-Dependent Yields of HO and OH by Aqueous-Phase Ozonolysis of -Cresol in the Atmosphere.

Hydrogen peroxide (HO) and hydroxyl radical (OH) are important oxidants in the atmospheric aqueous phase such as cloud droplets and deliquescent aerosol particles, playing a significant role in the chemical transformation of organic and inorganic pollutants in the atmosphere. Atmospheric aqueous-phase chemistry has been considered to be a source of HO and OH. However, our understanding of the mechanisms of their formation in atmospheric waters is still incomplete.

HKUST-1-derived highly ordered Cu nanosheets with enriched edge sites, stepped (211) surfaces and (200) facets for effective electrochemical CO reduction.

A novel electrode composed of Cu nanosheets constructed from nanoparticles was synthesized by in situ electrochemical derivation from the metal-organic framework (MOF) HKUST-1. The prepared derivative electrode (HE-Cu) exhibited higher Faradaic efficiency (FE, 56.0%) of electrochemical CO reduction (COR) compared with that of pristine Cu foil (p-Cu, 32.

Clinical Observation and Prognostic Analysis of Patients With Bloodstream Infection.

Background And Purpose: The clinical prognosis of Klebsiella pneumoniae() bloodstream infection is poor, and the prevalence of drug-resistant bacteria makes clinical anti-infective treatment more challenging. This retrospective study evaluated the epidemiological characteristics of patients with , the risk factors for drug-resistant bacterial infection and death, and analyzed treatment options.

Methods: Clinical data of 297 patients diagnosed with bacteremia between June 2014 and June 2019 were collected.

TiO quantum dots loaded sulfonated graphene aerogel for effective adsorption-photocatalysis of PFOA.

With the pollution of perfluoroalkyl substances (PFASs) became increasingly serious, the researches focused on removal of PFASs by adsorption-photocatalysis method has attracted considerable attention. To make the catalyst TiO disperse uniformly as quantum dots onto hydrophobic surface which was liable to attract perfluorooctanoic acid (PFOA), the surfactant sodium dodecyl sulfate (SDS) were used in this work, which not only connected the hydrophilic TiCl to the hydrophobic sulfonated graphene (SG) nanosheets, but also behaved as the molecular template for controlled nucleation and growth of the nanostructured TiO. After 3D SG-TiO QD nanosheets were fabricated, a series of 3D SG-TiO QD aerogels were self-assembled by ice-template.

Biochemical and genetic toxicity of dinotefuran on earthworms (Eisenia fetida).

Dinotefuran is a third-generation neonicotinoid insecticide, that is considered promising due to its excellent properties. In the present work, the biochemical and genetic toxicity of dinotefuran on earthworms were evaluated at a series of environmental background concentrations. Meanwhile, the effective concentrations of dinotefuran in artificial soil during the entire exposure period were monitored.

Residue analysis and risk assessment of tebuconazole in jujube (Ziziphus jujuba Mill).

In this study, a sensitive and reliable analytical method, based on a modified Quick, Easy, Cheap, Effective, Rugged and Safe procedure, was established for determination of tebuconazole in jujube. After extraction with acetonitrile, the samples were cleaned up by dispersive solid-phase extraction with primary secondary amine, and determined by high-performance liquid chromatography tandem mass spectrometry. At fortification levels of 0.

Dissipation and residues of myclobutanil in tobacco and soil under field conditions.

Field experiments were conducted in two different locations to determine the dissipation pattern and residue levels of myclobutanil in tobacco leaves and soil. Myclobutanil 12.5 % microemulsion (ME) formulation was sprayed once at 3.

Dissolved organic nitrogen (DON) profile during backwashing cycle of drinking water biofiltration.

A comprehensive investigation was made in this study on the variation of dissolved organic nitrogen (DON) during a whole backwashing cycle of the biofiltration for drinking water treatment. In such a cycle, the normalized DON concentration (C(effluent)/C(influent)) was decreased from 0.98 to 0.

Enhanced β-galactosidase production from whey powder by a mutant of the psychrotolerant yeast Guehomyces pullulans 17-1 for hydrolysis of lactose.

In order to isolate β-galactosidase overproducers of the psychrotolerant yeast Guehomyces pullulans 17-1, its cells were mutated by using nitrosoguanidine (NTG). One mutant (NTG-133) with enhanced β-galactosidase production was obtained. The mutant grown in the production medium with 30.

Disruption of the gene encoding β-1, 3-glucanase in marine-derived Williopsis saturnus WC91-2 enhances its killer toxin activity.

As the β-1, 3-glucanase produced by the marine-derived Williopsis saturnus WC91-2 could inhibit the activity of the killer toxin produced by the same yeast, the WsEXG1 gene encoding exo-β-1, 3-glucanase in W. saturnus WC91-2 was disrupted. The disruptant WC91-2-2 only produced a trace amount of β-1, 3-glucanase but had much higher activity of killer toxin than W.

Removal of dichloroacetic acid from drinking water by using adsorptive ozonation.

Chloroacetic acids, formed during the disinfection process in potable water production, are considered to pose a potential risk to human health. This article deals with dichloroacetic acid (DCAA) removal from drinking water by using a process of bentonite based adsorptive ozonation. This process is formed by combined addition of ozone, bentonite and Fe(3+).

A GH57 family amylopullulanase from deep-sea Thermococcus siculi: expression of the gene and characterization of the recombinant enzyme.

The gene encoding a new extracellular amylopullulanase (type II pullulanase) was cloned from an extremely thermophilic anaerobic archaeon Thermococcus siculi strain HJ21 isolated previously from a deep-sea hydrothermal vent. The functional hydrolytic domain of the amylopullulanase (TsiApuN) and its MalE fusion protein (MTsiApuN) were expressed heterologously. The complete amylopullulanase (TsiApu) was also purified from fermentation broth of the strain.

[Microorganisms of special herb-glycosidases and their fermentation, enzyme properties].

Herb-glycosides are main active elements of Zhongcaoyao (Chinese traditional medicines, Chinese medical herbs). However, the herb-glycoside structures are not optimal active structure for the human bodies. After orally taken up, the herb-glycosides of Zhongcaoyao could be changed into other more active structures by the digestive system such as enzymes and intestinal microorganisms; then degraded and absorbed in the human body and play the real role of pharmic effect; but only a small amount could be changed and controlled by circadian state of the human body.

Hymenobacter daecheongensis sp. nov., isolated from stream sediment.

A Gram-negative, strictly aerobic, non-spore-forming, rod-shaped, red-pink bacterium, designated strain Dae14(T), was isolated from stream sediment collected near Daecheong Dam, South Korea, and its taxonomic position was investigated by using a polyphasic approach. Phylogenetic analysis of 16S rRNA gene sequences showed that strain Dae14(T) belonged to the genus Hymenobacter. Sequence similarities between strain Dae14(T) and the type strains of Hymenobacter species with validly published names ranged from 91.

Spirosoma panaciterrae sp. nov., isolated from soil.

A Gram-negative, yellowish bacterial strain, designated Gsoil 1519(T), was isolated from soil of a ginseng field in Pocheon province (South Korea) and characterized using a polyphasic approach to determine its taxonomic position. Comparative 16S rRNA gene sequence analysis showed that strain Gsoil 1519(T) belongs to the family 'Flexibacteraceae' and is related to Spirosoma rigui KCTC 12531(T) (91.8 % similarity) and Spirosoma linguale LMG 10896(T) (91.