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Perfluorinated compounds (PFCs) and their short-chain derivatives are contaminants found globally. Adsorption research on volatile perfluorinated compounds (VPFCs), which are the main PFCs substances that undergo transfer and migration, is particularly important. In this study, new fluorine-containing tail materials (FCTMs) were prepared by combining fluorine-containing tail organic compounds with modified glass fibers. The adsorption effects of these FCTMs were generally stronger than that of pure activated glass fibers without fluorine- tailed, with an adsorption efficiency of up to 86% based on F–F interactions. The results showed that the FCTMs had improved desorption efficiency and reusability, and higher adsorption efficiency compared with that of polyurethane foam. FTGF was applied to the active sampler, and the indoor adsorption of perfluorovaleric acid was up to 2.45 ng/m3. The adsorption kinetics and isotherm simulation results showed that the adsorption process of typical perfluorinated compounds conformed to the second-order kinetics and Langmuir model. Furthermore, Nuclear Magnetic Resonance (NMR) results showed that the chemical shift in the fluorine spectrum was significantly changed by F–F interactions. This research provides basic theoretical data for the study of VPFCs, especially short-chain VPFCs, facilitating improved scientific support for the gas phase analysis of VPFCs in the environment.

Metal components in fine particulate matter (PM2.5) are closely associated with many adverse health outcomes. Dynamic changes of metals in PM2.5 are critical for risk assessment due to their temporal variations. Herein, an online method for real-time determination of multi-elements (As, Cd, Cs, Cu, Fe, Mg, Mn, Pb, Rb, Sn, Tl, and V) in PM2.5 was established by directly introducing air samples into inductively coupled plasma mass spectrometry (ICPMS). Meanwhile, a quantified method using metal standard aerosols (Cr, Mo, and W) and high time resolution for 3.3 min online measurement was developed and validated. The limits of detection were in the range of 0.001–6.30 ng/m3 for different metals. Subsequently, the real-time contents of multi-elements in PM2.5 for 12 h over 33 days were measured at different air qualities. Temporal variations of crustal elements like Fe, Mg are similar to PM2.5, whereas toxic elements (Pb, As and Cd) have upward trends at dusk. This denoted the association with various emission sources and different exposure concentrations of metals. In addition to the acquisition of real-time information, online analysis of multi-elements in PM2.5 is beneficial for atmospheric monitoring and provides critical insights into the different exposure risks of metals in PM2.5 at varying times.

Biomonitoring is an effective way to assess the effects of pollutants on marine ecosystems. As an important fishing region in China, the Chinese Bohai Sea has been contaminated with heavy metals, posing great risks to seafood safety and human health. Herein, the spatiotemporal variations in the concentrations of seven heavy metals (As, Cd, Cr, Cu, Ni, Pb, and Zn) in 11 species of mollusks (658 samples) collected from the Chinese Bohai Sea were studied during 2006–2016. The concentrations of Cr, As, Cd, and Pb in approximately 41%, 100%, 71%, and 18% of the sampled mollusks exceeded the maximum permissible levels in aquatic products set by China, indicating that the mollusks were contaminated with varied concentrations of heavy metals. Except for slight fluctuations, no significant temporal variations were observed during the sampling period, suggesting a relatively stable status of these metals. Cluster analysis showed that oyster had higher bioaccumulation potential for Zn and Cu, whereas Mactra veneriformis, Rapana venosa, Meretrix meretrix, Chlamys farreri, and Mya arenaria had higher bioaccumulation potentials for Cr, As, Ni, Cd, and Pb, respectively. These findings are useful for biomonitoring and developing guidelines for seafood consumption in coastal regions. Significant relationships were observed between heavy metal concentrations in mollusks and socioeconomic indices (gross domestic product, per capita gross domestic product, and population amount), suggesting the effects of anthropogenic activities on heavy metal contamination. Our study established a good model to evaluate the risks of heavy metals and provided a sound scientific basis for controlling seafood safety in coastal regions.

In response to the enormous threat to human survival and development caused by the large number of viruses, it is necessary to strengthen the defense against and elimination of viruses. Metallic materials have been used against viruses for thousands of years due to their broad-spectrum antiviral properties, wide sources and excellent physicochemical properties; in particular, metal nanoparticles have advanced biomedical research. However, researchers in different fields hold dissimilar views on the antiviral mechanisms, which has slowed down the antiviral application of metal nanoparticles. As such, this review begins with an exhaustive compilation of previously published work on the antiviral capacity of metal nanoparticles and other materials. Afterwards, the discussion is centered on the antiviral mechanisms of metal nanoparticles at the biological and physicochemical levels. Emphasis is placed on the fact that the strong reducibility of metal nanoparticles may be the main reason for their efficient inactivation of viruses. We hope that this review will benefit the promotion of metal nanoparticles in the antiviral field and expedite the construction of a barrier between humans and viruses.

Adsorption of Hg2+ and methylmercury (MeHg) to multi-walled carbon nanotubes (MWCNTs) modified, respectively, with hydroxyl, amine and carboxyl groups was studied. The effect of various factors like the initial pH, natural organic matter (NOM), Cl- and adsorbent dose on the sorption efficiency were evaluated. It was found that amine-modified MWCNTs showed a strong adsorption capacity to Hg2+ and MeHg, and the removal efficiency could reach up to 92% (0.5 g/L MWCNTs, and 100 μg/L Hg2+ and MeHg) which is independent of pH. NOM had complex effects on the adsorption of Hg2+ and MeHg to MWCNTs. Cl- inhibited the adsorption of Hg2+ and MeHg to MWCNTs. The adsorption of Hg2+ and MeHg was found to be inhomogeneous and homogeneous chemisorption, respectively. Our results suggested that MWCNTs modified with different functional groups can efficiently adsorb both Hg2+ and MeHg in aqueous environment.

Mercury (Hg) and its compounds are much concerned for their high toxicity and wide presence in the environment. Since the toxicity of Hg is species dependent, various methods have been developed for the speciation analysis of Hg. This review focus on the determination and speciation analysis of Hg chemical species in water, sediment, and soil samples. Recent developments on sample pre-treatment and extraction/pre-concentration, separation, and quantification of Hg chemical species, and associated analytical challenges have been reviewed and briefly discussed based on recent reports.

In order to investigate the anti-inflammatory activity of egg yolk-derived phosphopeptides (PPPs), intestinal epithelial (Caco-2 cells, HT-29 cells) and macrophage RAW 264.7 cell lineages were stimulated with either tumor necrosis factor alpha (TNF-α) or Salmonella enterica lipopolysaccharide (LPS). Upon pre-incubation with different doses of PPPs, the secretion of interleukin 8 (IL-8) and TNF-α in cell supernatants was quantified by enzyme-linked immunosorbent assay (ELISA). The gene expression levels of inducible nitric oxide synthase (iNOS) and pro-inflammatory cytokines (i.e., IL-8, IL-12, IL-6, monocyte chemoattractant protein-1 (MCP-1), TNF-α, IL-1β) were determined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Results revealed that PPPs significantly inhibit the secretion of IL-8 in TNF-α-stimulated Caco-2 and HT-29 cells in a dose-dependent manner; while no significant difference was observed in LPS-stimulated Caco-2 and HT-29 cells. Interestingly, the expression of IL-8, MCP-1 and IL-12 was inhibited by PPPs in both TNF-α- and LPS-stimulated HT-29 cells, and similarly, the expression of TNF-α, IL-1β, IL-6, and iNOS was downregulated significantly in LPS-stimulated macrophage RAW 264.7 cells pre-incubated with PPPs. We conclude that PPPs possesses anti-inflammatory properties evidenced by the down-regulation of key pro-inflammatory markers. Thus our results suggest that PPPs may serve as nutraceutical compounds with anti-inflammatory properties.

Spontaneous generation of reactive oxygen species (ROS) in aqueous microdroplets or at a water vapor–silicate interface is a new source of redox chemistry. However, such generation occurs with difficulty in liquid water having a large ionic strength. We report that ROS is spontaneously produced when water vapor contacts hydrogen-bonded hydroxyl groups on a silicate surface. The evolution of hydrogen-bonded species such as hydroxyl groups was investigated by using two-dimensional, time-resolved FT-IR spectroscopy. The participation of water vapor in ROS generation is confirmed by investigating the reaction of D2O vapor and hydroxyl groups on a silicate surface. We propose a reaction pathway for ROS generation based on the change of the hydrogen-bonding network and corresponding electron transfer onto the silicate surface in the water vapor–solid contact process. Our observations suggest that ROS production from water vapor–silicate contact electrification could have contributed to oxidation during the Archean Eon before the Great Oxidation Event. [ABSTRACT FROM AUTHOR]

Contact electrification between water and a solid surface is crucial for physicochemical processes at water-solid interfaces. However, the nature of the involved processes remains poorly understood, especially in the initial stage of the interface formation. Here we report that H2O2 is spontaneously produced from the hydroxyl groups on the solid surface when contact occurred. The density of hydroxyl groups affects the H2O2 yield. The participation of hydroxyl groups in H2O2 generation is confirmed by mass spectrometric detection of 18O in the product of the reaction between 4-carboxyphenylboronic acid and 18O-labeled H2O2 resulting from 18O2 plasma treatment of the surface. We propose a model for H2O2 generation based on recombination of the hydroxyl radicals produced from the surface hydroxyl groups in the water-solid contact process. Our observations show that the spontaneous generation of H2O2 is universal on the surfaces of soil and atmospheric fine particles in a humid environment. [ABSTRACT FROM AUTHOR]

The mercury (Hg) loadings to the coastal regions of China have significantly increased in the last decades, and it is thus critical to unravel the input pathway and historical influx of these Hg. Here, concentrations and isotope compositions of Hg in three sediment cores collected from different mud areas of eastern China seas were comprehensively analyzed to investigate the spatial and temporal Hg inputs. The sediment core from nearshore mud area had distinctly higher δ202Hg and lower Δ199Hg values than those from offshore mud area, exhibiting an obvious difference in dominant Hg sources (land-based vs. atmospheric). An isotope mixing model on basis of Hg isotope signatures of these cores revealed that the contributions of Hg sources varied significantly not only among different sites but also among different periods. Rapid development of industrialization and urbanization since the 1980s have significantly increased Hg especially industrial Hg inputs into eastern China seas. Our study suggests that the central mud area of Yellow Sea could well record the historical influxes of different Hg sources especially atmospheric Hg, as well as historical Hg emission events like industrialization/urbanization and modern Chinese wars, which would contribute to reconstruct the chronology of Hg inputs into eastern China seas. [ABSTRACT FROM AUTHOR]

Marine boundary layer (MBL) is the largest transport place and reaction vessel of atmospheric mercury (Hg). The transformations of atmospheric Hg in MBL are crucial for the global transport and deposition of Hg. Herein, Hg isotopic signatures in total gaseous mercury (TGM) and particulate bound Hg (PBM) collected during three cruises to Chinese seas in summer and winter were measured to reveal the transformation processes of atmospheric Hg in the MBL. Unlike the observation results at inland sites, isotopic compositions in TGM from MBL were shaped not only by mixing continental emissions, but also largely by the oxidation of Hg0 primarily derived by Br atoms. Lower air temperature could promote the positive MIF in TGM in summer, while the relative processes might be weak in winter. In contrast, the positive Δ199Hg and high ratios of Δ199Hg / Δ201Hg in PBM indicated that alternative oxidants other than Br or Cl atoms played a major role in the formation of Hg(II) in PBM, likely following the nuclear volume effect. Our results suggested the importance of local Hg environmental behaviours caused by an abundance of highly reactive species, and provided new evidence for understanding the complicated transformations of atmospheric Hg in the MBL. [ABSTRACT FROM AUTHOR]

Using petroleum ether to extract an antimicrobial cerebroside from the liposoluble constituent of cervus nippon antler velvet layer was studied in this paper. Single-factor experiment was used to research the effect of liquid-to-solid ratio, standing time and centrifugation time on the extraction of crude cerebroside. The optimal extraction conditions for the cerebroside as follows: liquid-to-solid ratio 15, standing time 45 min, and centrifugation time 6 min. The extracted cerebroside was purified and identified by using silica gel column and TLC, respectively. IR analysis showed that the extraction has hydroxyl and amide groups, which was proved to be cerebroside. Meanwhile, bioactivity showed that the extraction has antibacterial activity, and the purified one is better than the crude one. [ABSTRACT FROM AUTHOR]

A simple, clean, and efficient method has been developed for generating hydroxyl radicals on a nitrocellulose membrane (NCM) under light of wavelengths greater than 280 nm. Hydroxyl radicals formed on the NCM surface, diffusing into the bulk solution under irradiation. Radical generation was shown to be dependent on the nature of the NCM and light, and independent of the properties of the bulk solution. The quantum yield for hydroxyl radicals from the NCM was 1.72x10-4, which is approximately 2.46 times that from TiO2. This hydroxyl radical generation method was preliminarily applied in the photodegradation of organic pollutants, in which electrostatic interactions between the pollutant molecules and the NCM surface were found to play a key role. Further applications of this hydroxyl radical generation method should be assessed. [ABSTRACT FROM AUTHOR]

Mercury sulfide (HgS, cinnabar, and metacinnabar) is a major Hg sink, widely available in various environmental compartments. The formation and dissolution of HgS play a crucial role in the geochemical cycle of Hg, including its transport, reduction, methylation, and toxicity. Unlike other Hg species (e.g., methylmercury, Hg0), environmental HgS occurs in the form of different sized particles, leading to various challenges regarding its quantification and the evaluation of potential environmental impacts. This review summarizes the current analytical methods for the identification, characterization, and quantification of HgS, including sequential chemical extraction, X-ray absorption spectroscopy, programmed thermal desorption, and selective vapor generation, among other methods. In addition, the chemical/biological pathways and mechanisms involved in the formation and dissolution of HgS are reviewed, as are the analytical and environmental perspectives of HgS. This review furthers our understanding and encourages the study of the environmental formation and dissolution of HgS and its role in the geochemical cycle of Hg. [ABSTRACT FROM AUTHOR]

Species-specific stable isotope dilution in combination with gold trap- or gas chromatography (GC)-inductively coupled plasma mass spectrometry (ICP-MS) is reported for the determination of inorganic mercury and methylmercury in diatoms (Chaetoceros curvisetus). The optimum conditions for the separation parameters were established. The isotope dilution analysis was performed using 199Hg-enriched Hg2+ and laboratory-synthesized 201Hg-enriched methylmercury. The absolute detection limits obtained with isotope dilution-ICP-MS were 9 pg for total mercury and 0.6 pg for methylmercury. The relative error of 7 Hg isotopic abundances based on the peak area measurements was better than 2.0% for 20 pg of methylmercury (as Hg) and 250 pg of inorganic mercury. The accuracy of the method was validated with a biological certified reference material. The developed method was then applied to investigate the uptake of inorganic mercury and methylmercury by C. curvisetus. Continuous uptake of inorganic mercury and methylmercury was observed during 5 days of incubation. [ABSTRACT FROM AUTHOR]

Photochemical halogenation of dissolved organic matter (DOM) may represent an important abiotic process for the formation of natural organobromine compounds (OBCs) and natural organoiodine compounds (OICs) within surface waters. Here we report the enhanced formation of OBCs and OICs by photohalogenating DOM in freshwater and seawater, as well as the noticeable difference in the distribution and composition pattern of newly formed OBCs and OICs. By using negative ion electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry, various OBCs and OICs were identified during the photohalogenation processes in sunlit waters. The respective number of OBCs and OICs formed in artificial seawater (ASW) under light radiation was higher than that in artificial freshwater (AFW), suggesting a possible role of the mixed reactive halogen species. OBCs were formed mainly via substitution reactions and addition reactions accompanied by other reactions and distributed into three classes: unsaturated hydrocarbons with relatively low oxygen content, unsaturated aliphatic compounds, and saturated fatty acids and carbohydrates with relatively high hydrogen content. Unlike the OBCs, OICs were located primarily in the region of carboxylic-rich alicyclic molecules composed of esterified phenolic, carboxylated, and fused alicyclic structures and were generated mainly through electrophilic substitution of the aromatic proton. Our findings call for further investigation on the exact structure and toxicity of the OBCs and OICs generated in the natural environment. [ABSTRACT FROM AUTHOR]

Ubiquitous natural organic matter (NOM) plays an important role in the aggregation state of engineered silver nanoparticles (AgNPs) in aquatic environment, which determines the transport, transformation, and toxicity of AgNPs. As various capping agents are used as coatings for nanoparticles and NOM are natural polymer mixture with wide molecular weight (MW) distribution, probing the particle coating-dependent interaction of MW fractionated natural organic matter (Mf-NOM) with various coatings is helpful for understanding the differential aggregation and transport behavior of engineered AgNPs as well as other metal nanoparticles. In this study, we investigated the role of pristine and Mf-NOM on the aggregation of AgNPs with Bare, citrate, and PVP coating (Bare-, Cit-, and PVP-AgNP) in mono- and divalent electrolyte solutions. We observed that the enhanced aggregation or dispersion of AgNPs in NOM solution highly depends on the coating of AgNPs. Pristine NOM inhibited the aggregation of Bare-AgNPs but enhanced the aggregation of PVP-AgNPs. In addition, Mf-NOM fractions have distinguishing roles on the aggregation and dispersion of AgNPs, which also highly depend on the AgNPs coating as well as the MW of Mf-NOM. Higher MW Mf-NOM (>100 kDa and 30-100 kDa) enhanced the aggregation of PVP-AgNPs in mono- and divalent electrolyte solutions, whereas lower MW Mf-NOM (10-30 kDa, 3-10 kDa and <3 kDa) inhibited the aggregation of PVP-AgNPs. However, all the Mf-NOM fractions inhibited the aggregation of Bare-AgNPs. For PVP- and Bare-AgNPs, the stability of AgNPs in electrolyte solution was significantly correlated to the MW of Mf-NOM. But for Cit-AgNPs, pristine NOM and Mf-NOM has minor influence on the stability of AgNPs. These findings about significantly different roles of Mf-NOM on aggregation of engineered AgNPs with various coating are important for better understanding of the transport and subsequent transformation of AgNPs in aquatic environment. [ABSTRACT FROM AUTHOR]

High intensity pulsed electric fields (PEF) was used to extract chondroitin sulphate (CS) from fish bone. Results show that PEF extraction speed is much faster, and the content of CS is much higher compared with traditional methods. Variation of PEF parameters and the content of CS were determined by single factor experiments. The processing conditions were optimised by quadratic general rotary unitised design experiments. The maximum yield of 6.92 g/L was achieved under the following conditions: material-liquid ratio of 1:15 g/mL, electric field intensity of 16.88 kV/cm, pulse number of 9, and NaOH concentration of 3.24%. The purity of CS was analysed by agarose gel electrophoresis. CS purity was high, and the extract did not contain any other glycosaminoglycans. PEF can be widely used to extract CS with non-thermal performance, high speed, and low pollution. [ABSTRACT FROM AUTHOR]

Photoinduced reduction of silver ion (Ag+) to silver nanoparticles (AgNPs) by dissolved organic matter (DOM) plays a crucial role in the transformation and transport of engineered AgNPs and Ag+ in aquatic environments. DOM is a mixture of natural polymers with wide molecular weight (MW) distribution, and the roles of specific components of DOM in the photo reduction of Ag+ to AgNPs are still not understood. In this study, MW fractionated natural organic matter (Mf-NOM) were investigated for their roles on the photoreduction process and stabilization of the formed AgNPs. This photoinduced reduction process depends highly on pH, concentration of Ag+ and NOM, light quality, and the MW of Mf-NOM. Monochromatic radiation and light attenuation correction suggested that the difference of Mf-NOM on reduction was mainly ascribed to the differential light attenuation of Mf-NOM rather than the "real" reductive ability. More importantly, compared with low MW fractions, the high MW Mf-NOMs exhibit drastically higher capability in stabilizing the photosynthesized AgNPs against Ca2+-induced aggregation. This finding is important for a better understanding of the differential roles of Mf-NOM in the transformation and transport of Ag+ and engineered AgNPs in DOMrich surface water. [ABSTRACT FROM AUTHOR]

Naturally occurring Au nanoparticles (AuNPs) have been widely observed in ore deposits, coal, soil, and environmental water. Identifying the source of these naturally occurring AuNPs could be helpful for not only the discovery of Au deposits through advanced exploration methods, but also the elucidation of the biogeochemical cycle and environmental toxicity of ionic Au and engineered AuNPs. Here, we investigated the effect of natural/simulated sunlight and heating on the reduction of ionic Au by ubiquitous dissolved organic matter (DOM) in river water. The reductive process probed by X-ray photoelectron spectroscopy revealed that phenolic, alcoholic, and aldehyde groups in DOM act as reductive sites. Long-time exposure with thermal and photoirradiation induced the further fusion and growth of AuNPs to branched Au nanostructure as precipitation. The formation processes and kinetics of AuNPs were further investigated using humic acid (HA) as the DOM model, with comprehensive characterizing methods. We have observed that HA can reduce ionic Au(III) complex (as chloride or hydroxyl complex) to elemental Au nanoparticles under sunlight or heating. In this process, nearly all of the Au(III) could be reduced to AuNPs, in which HA serves as not only the reductive agent, but also the coating agent to stabilize and disperse AuNPs. The size and stability of AuNPs were highly dependent on the concentration ratio of Au(III) to HA. These results imply that, besides biological processes, this thermal or photochemical reduction process is another possible source of naturally occurring AuNPs in natural environments, which possibly has critical impacts on the transport and transformation of Au and engineered AuNPs. [ABSTRACT FROM AUTHOR]

A gene (Tpen_1458) encoding a putative alpha amylase from hyperthermophilic archaeon Thermofilum pendens (TfMA) was cloned and expressed in Escherichia coli. The recombinant amylolytic enzyme was purified by Ni-NTA affinity chromatography and its catalytic properties were examined. Purified TfMA was extremely thermostable with a half-life of 60 min at an optimal temperature of 95°C. TfMA activity increased to 136% in the presence of 5 mM CaCl2. Maximal activity was measured toward γ-cyclodextrin with a specific activity of 56 U/mg using copper bicinchoninate method. TfMA catalyzed the ring-opening reaction by cleaving one α-1,4-glycosidic linkage of cyclodextrin to produce corresponding single maltooligosaccharide at the initial time. The final products from cyclodextrins, linear maltooligosaccharides, and starch were glucose and maltose, and TfMA could also degrade pullulan and amylase inhibitor acarbose to panose and acarviosine-glucose, respectively. These results revealed that TfMA is a novel maltogenic amylase. [ABSTRACT FROM AUTHOR]

Speciation of mercury was accomplished by using a simple interface with photo-induced chemical vapour generation in a high performance liquid chromatography—atomic fluorescence spectrometry (HPLC-AFS) hyphenated system. Acetic acid and 2-mercaptoethanol in the mobile phase were used as photochemical reagent. The operating parameters were optimized to give limits of detection of 0.53 µg L−1, 0.22 µg L−1, 0.18 µg L−1 and 0.25 µg L−1 for inorganic mercury, methylmercury, ethylmercury and phenylmercury, respectively. The method was validated with the certified reference material DORM-2 and applied to the analysis of seafood samples. The HPLC-AFS hyphenated system is simple, environmentally friendly, and represents an attractive alternative to the conventional peroxothiosulfate-borohydride method. [ABSTRACT FROM AUTHOR]

We propose an extraction methodology to extract toxic mercury species including methylmercury (MeHg) and ethylmercury (EtHg) in coal by comparing different extraction methods (shaking, ultrasonic and microwave assisted extraction) using different extraction solvents (TMA, KOH/CH3OH, HCl, and acidic CuSO4/KBr). Microwave assisted extraction at the power of 90 W for 5 min using TMA (tetramethylammonium hydroxide) as the extractant provided the highest and the most satisfactory extraction efficiency for MeHg and EtHg. Speciation analysis of mercury was done by HPLC-AFS. The obtained concentrations in a certified reference material (CRM-580) were in good agreement with the certificated values. Ten coal samples from China were analyzed using the proposed method. MeHg was detected in most of the samples (6 out of 10) and EtHg was detected only in one. The concentrations were at the sub-ng level. Other forms of organomercuries might be found in the samples. Considering the high toxicities of organomercuries and the huge amount of coal consumption every year, people should be made more aware. [ABSTRACT FROM AUTHOR]