Homologous Overexpression of Tyrosinase in Trichoderma reesei and Its Application in Glycinin Cross-Linking.

Tyrosinase is capable of oxidizing tyrosine residues in proteins, leading to intermolecular protein cross-linking, which could modify the protein network of food and improve the texture of food. To obtain the recombinant tyrosinase with microbial cell factory instead of isolation tyrosinase from the mushroom Agaricus bisporus, a TYR expression cassette was constructed in this study. The expression cassette was electroporated into Trichoderma reesei Rut-C30 and integrated into its genome, resulting in a recombinant strain C30-TYR. After induction with microcrystalline cellulose for 7 days, recombinant tyrosinase could be successfully expressed and secreted by C30-TYR, corresponding to approximately 2.16 g/L tyrosinase in shake-flask cultures. The recombinant TYR was purified by ammonium sulfate precipitation and gel filtration, and the biological activity of purified TYR was 45.6 U/mL. The purified TYR could catalyze the cross-linking of glycinin, and the emulsion stability index of TYR-treated glycinin emulsion was increased by 30.6% compared with the untreated one. The cross-linking of soy glycinin by TYR resulted in altered properties of oil-in-water emulsions compared to emulsions stabilized by native glycinin. Therefore, cross-linking with this recombinant tyrosinase is a feasible approach to improve the properties of protein-stabilized emulsions and gels.

Effects of the polyhalogenated carbazoles 3-bromocarbazole and 1,3,6,8-tetrabromocarbazole on soil microbial communities.

Soil ecosystems are being more contaminated with polyhalogenated carbazoles (PHCZs), which raising much attention about their impact on soil microorganisms. 3-Bromocarbazole (3-BCZ) and 1,3,6,8-tetrabromocarbazole (1,3,6,8-TBCZ) are two typical PHCZs with high detection rates in the soil environment. However, ecological risk research on these two PHCZs in soil is still lacking. In the present study, after 80 days of exposure, the ecological influence of 3-BCZ and 1,3,6,8-TBCZ was investigated based on 16S rDNA sequencing, ITS sequencing, gene (16S rDNA, ITS, amoA, nifH, narG and cbbL) abundance and soil enzyme activity. The results showed that the bacterial 16S rDNA gene abundance significantly decreased under 3-BCZ and 1,3,6,8-TBCZ exposure after 80 days of incubation. The fungal ITS gene abundance significantly decreased under 1,3,6,8-TBCZ (10 mg/kg) exposure. PHCZs contributed to the alteration of bacteria and fungi community abundance. Bacteria Sphingomonas, RB41 and fungus Mortierella, Cercophora were identified as the most dominant genera. The two PHCZs consistently decreased the relative abundance of Sphingomonas, Lysobacter, Dokdonella, Mortierella and Cercophora etc at 80th day. These keystone taxa are related to the degradation of organic compounds, carbon metabolism, and nitrogen metabolism and may thus have influence on soil ecological functions. Bacterial and fungal functions were estimated using functional annotation of prokaryotic taxa (FAPROTAX) and fungi functional guild (FUNGuild), respectively. The nitrogen and carbon metabolism pathway were affected by 3-BCZ and 1,3,6,8-TBCZ. The soil nitrogen-related functions of aerobic ammonia oxidation were decreased but the soil carbon-related functions of methanol oxidation, fermentation, and hydrocarbon degradation were increased at 80th day. The effects of 3-BCZ and 1,3,6,8-TBCZ on the abundances of the amoA, nifH, narG, and cbbL genes showed a negative trend. These results elucidate the ecological effects of PHCZs and extend our knowledge on the structure and function of soil microorganisms in PHCZ-contaminated ecosystems.

Effects of the fungicide trifloxystrobin on the structure and function of soil bacterial community.

Trifloxystrobin has been widely applied to prevent fungal diseases because of its high efficiency and desirable safety characteristics. In the present study, the effects of trifloxystrobin on soil microorganisms were integrally investigated. The results showed that trifloxystrobin inhibited urease activity, promoted dehydrogenase activity. Downregulated expressions of the nitrifying gene (amoA), denitrifying genes (nirK and nirS), and carbon fixation gene (cbbL) were also observed. Soil bacterial community structure analysis showed that trifloxystrobin changed the abundance of bacteria genera related to nitrogen and carbon cycle in soil. Through the comprehensive analysis of soil enzymes, functional gene abundance, and soil bacterial community structure, we concluded that trifloxystrobin inhibited both nitrification and denitrification of soil microorganisms, and also diminished the carbon-sequestration ability. Integrated biomarker response analysis showed that dehydrogenase and nifH were the most sensitive indicators of trifloxystrobin exposure. It provides new insights about trifloxystrobin environmental pollution and its influence on soil ecosystem.

The effect of TiO2NPs on cloransulam-methyl toxicity to earthworm (Eisenia fetida).

Cloransulam-methyl is a new herbicide and has broad application prospect. However, the effect of cloransulam-methyl on earthworm have yet to be clarified. As more and more titanium dioxide nanoparticles (TiO2NPs) enter the soil, cloransulam-methyl and TiO2NPs have a risk of co-exposure, but the effect of TiO2NPs on cloransulam-methyl toxicity is unknown. In the study, the ecotoxicity of cloransulam-methyl (0.1, 1 mg kg-1) on earthworm and the effect of TiO2NPs (10 mg kg-1) on cloransulam-methyl toxicity was investigated after exposure for 28 and 56 d. Exposure tests showed cloransulam-methyl and cloransulam-methyl + TiO2NPs promoted the accumulation of reactive oxygen species, malondialdehyde and 8-hydroxydeoxyguanosine, increased the activities of superoxide dismutase and catalase, resulted in lipid peroxidation and DNA damage. Besides, the results at the genetic level showed cloransulam-methyl and cloransulam-methyl + TiO2NPs altered the expression of physiologically-related genes, which demonstrated that cloransulam-methyl and cloransulam-methyl + TiO2NPs induced oxidative stress and cell apoptosis, and disturbed the normal reproduction in earthworm. The results of comprehensive toxicity comparison indicated cloransulam-methyl and TiO2NPs co-exposure has higher toxicity compared to cloransulam single exposure. Our results suggest that TiO2NPs can enhance the toxicity of cloransulam-methyl on Eisenia fetida in terms of oxidative stress, cell apoptosis and reproduction aspects. Based on above studies, it is of great importance for evaluating the risk of cloransulam-methyl co-exposure with TiO2NPs in soil.

Development toxicity and cytotoxicity of pyroxsulam on embryos and adults of zebrafish (Danio rerio).

Pyroxsulam is a typical triazolopyrimidine sulfonamide herbicide, which plays a vital role in weed control for wheat production. Previous studies on pyroxsulam have mainly focused on weed resistance, control effects, and soil microorganisms, however, research on aquatic ecotoxicity is lacking. This study evaluated the toxicity of pyroxsulam in zebrafish embryos (120 h) and adults (14 and 28 d). Chronic exposure to pyroxsulam (0.2, 2, and 10 µg L-1) reduced reactive oxygen species (ROS) content in embryos but increased ROS content in adults. Pyroxsulam caused lipid peroxidation and DNA damage in embryos and adults. The expression of p53, bcl-2/bax, and caspase 3/8/9 indicated that pyroxsulam inhibited apoptosis in embryos but induced apoptosis in adults. By calculating integrated biomarker response, apoptosis was more readily affected than oxidative damage in embryos and adults. The toxicity of pyroxsulam increased with increasing concentration, however, with increasing exposure time, the toxicity of pyroxsulam to adults decreased. Pyroxsulam exerted toxic effects on zebrafish at different life stages (embryos and adults), and different stages had different toxicity. These results indicate that in future studies on the toxicity of pyroxsulam to zebrafish, different life stages (embryos and adults) need to be studied. The present study evaluated the toxicity of environmentally relevant concentrations of pyroxsulam to zebrafish embryos and adults, providing worthy data for assessing its effects on aquatic ecosystems.

Characterization of the responses of soil micro-organisms to azoxystrobin and the residue dynamics of azoxystrobin in wheat-corn rotation fields over two years.

Azoxystrobin, a high-efficiency and broad-spectrum strobilurin fungicide, has been widely used in global agricultural production. However, the effects of azoxystrobin on soil micro-organisms have scarcely been studied, and relevant experiments are usually conducted under laboratory conditions using active ingredient. Therefore, the effects of azoxystrobin on soil micro-organisms when applied to actual farmland are unknown. We sought to address this knowledge gap in this study, where we studied the effects of azoxystrobin on soil micro-organisms in a wheat-corn rotation field over two years. The results indicate that after two years of azoxystrobin application the activities of soil enzymes were inhibited, and the abundance of functional genes related to the nitrogen and carbon cycle were inhibited, which change the abundance of soil microbial bacteria of genera. As a consequence, the soil nitrogen and carbon cycles were disturbed. In addition, azoxystrobin inhibited the abundance of functional bacteria related to organic pollutant degradation and soil metabolism, where the rate of azoxystrobin degradation diminished over time. Moreover, azoxystrobin significantly inhibited the soil-culturable microbial population. The integrated biomarker response (IBR) indicated that the soil-culturable microbial population can be used as a sensitive indicator of the effect of azoxystrobin on soil micro-organisms. The final levels of azoxystrobin residues measured in grains were less than 0.004 mg/kg, lower than the maximum residue limits in European Union and China. The results of this study provide a basis for suggestions regarding the appropriate use of azoxystrobin in addition to support for elucidating the interaction between biological macromolecules and pollutants.

New insights into the effects of chlorpyrifos on soil microbes: Carbon and nitrogen cycle related microbes in wheat/maize rotation agricultural field.

Chlorpyrifos, a broad-spectrum organophosphorus insecticide, has been widely detected worldwide and is a potential neurotoxin and endocrine disruptor. Besides, chlorpyrifos has been proven that have a negative effect on soil microbes. In the present study, chlorpyrifos formulation (LORSBAN®, 45% emulsifiable concentrate) was applied in an agricultural field at the recommended dose (R dose, 270.0 and 337.5 g a.i. ha-1 for wheat and maize respectively) and double recommended (DR) dose. Chlorpyrifos residue level and effect on soil microbes related to soil carbon and nitrogen cycle function were analyzed. Results showed that the half-lives of chlorpyrifos in wheat and maize field soil were 7.23-8.23 and 1.45-1.77 d, respectively. Application of chlorpyrifos at even DR dose did not result in unacceptable residual chlorpyrifos, where the final residual chlorpyrifos in wheat/maize (leaf, stem, and grain) was meet the requirement of the maximum residual limit (0.5 mg kg-1 for wheat and 0.05 mg kg-1 for maize) in China. Chlorpyrifos enhanced the activity of ß-glucosidase by increasing the relative abundance of Sphingosinicella and promoted the carbon cycle in wheat field. The changes of cbbLR and cbbLG gene abundance also confirmed that chlorpyrifos could affect the import and export of soil carbon pool. The effect of chlorpyrifos on soil N cycle was determined by changes in the abundance of the bacterial genus Gemmatimonas, which is associated with denitrification. Further analysis of N-cycle functional genes and urease activity showed that chlorpyrifos inhibited nitrogen fixation in wheat field, but promoted nitrogen fixation in maize field. In general, bacterial abundance, urease, and AOA-amoA gene could be early warning markers of chlorpyrifos contamination. The results demonstrated the negative effects of chlorpyrifos on soil microbes especially on soil C and N cycle in actual agricultural field. It provides new insights about chlorpyrifos environmental pollution and its effect on soil ecosystems.

Effect of florasulam on oxidative damage and apoptosis in larvae and adult zebrafish (Danio rerio).

Florasulam is widely used for weed control in wheat fields due to its high activity and low dosage. Previous studies on florasulam have focused on soil microbial and residue determination, however, its ecotoxicity to aquatic organisms is unclear. The toxicity of florasulam was evaluated in larvae (120 h) and adult (14 and 28 d) zebrafish. After florasulam (0.1 and 1 µg L-1) exposure, reactive oxygen species levels in larvae and adult zebrafish significantly increased and antioxidant system was activated. Florasulam induced lipid peroxidation in larvae and adult zebrafish. Florasulam did not cause DNA damage to larvae but caused DNA damage to adult zebrafish. Changes in caspase 3/8/9 genes indicated that apoptosis was induced in larvae but inhibited in adult zebrafish. By calculating integrated biomarker response, caspase 3 and malondialdehyde could be used as early warning indicators of florasulam effect on larvae and adult zebrafish, respectively. The higher the exposure concentration, the greater the toxicity of florasulam to larvae and adult zebrafish. Increasing exposure time resulted in higher toxicity to adult zebrafish. Florasulam has different toxicity at larvae and adult zebrafish. In future studies to investigate florasulam toxicity to zebrafish, different zebrafish life stages (larvae and adult) need to be studied.

Toxicity comparison of atrazine on Eisenia fetida in artificial soil and three natural soils.

Atrazine has been widely used in the world and caused environmental pollution, especially soil pollution. When assessing the toxicity of atrazine in soil, most studies used standardized artificial soils, while few studies focused on the real soil environments. In the present study, three natural soils and artificial soil were selected as test soils to study and compare the toxicities of atrazine to Eisenia fetida. Acute toxicity of atrazine was determined by filter paper and soil tests. In chronic toxicity study, after atrazine exposure, the content of reactive oxygen species in Eisenia fetida significantly increased and showed a dose-response relationship. The activity changes of three antioxidant enzymes and glutathione transferase showed that atrazine had obvious oxidative stress effect on earthworms. The contents of malondialdehyde and 8-hydroxy deoxyguanosine in 0.1 and 1 mg/kg atrazine treatment groups were significantly higher than the control, indicating that medium and high concentrations of atrazine could cause lipid and DNA damage in Eisenia fetida. The acute toxicity results and the integrated biomarker response index for chronic toxicity indicated that the toxicity order of atrazine was: red clay > fluvo-aquic soil > artificial soil > black soil, and that the toxicity of atrazine in artificial soil was not representative of its toxicity in real soil environment. The results of correlation analysis showed that three soil property parameters of organic carbon, organic matter and sand were most related to the toxicity of atrazine.

Effects of ecotoxicity of penoxsulam single and co-exposure with AgNPs on Eisenia fetida.

Penoxsulam (PNX) and silver nanoparticles (AgNPs) are likely to coexist in soils due to continuous use. However, the ecotoxicity of PNX in earthworms and the effect of AgNPs on PNX toxicity are unknown. Therefore, the toxicity of PNX (0.05, 0.5, and 2.5 mg/kg) single and co-exposure with AgNPs (10 mg/kg) after 28 and 56 days on Eisenia fetida (E. fetida) was investigated from biochemical, genetic, histopathological, and transcriptomic aspects. The results showed that the low concentration of PNX (0.05PNX) had almost no effect on the biochemical level of E. fetida. However, the addition of AgNPs resulted in 0.05PNX causing E. fetida to produce excessive reactive oxygen species, and the activity of antioxidant and detoxification enzymes were interfered, resulting in lipid peroxidation and DNA damage. From the genetic level, even the lowest concentration of PNX can significantly interfere with the expression of functional genes, thus inducing oxidative stress and apoptosis and inhibited reproductive behavior in E. fetida. The integrated biomarker response results at the biochemical and genetic levels showed that the comprehensive toxicity of PNX and PNX + AgNPs on E. fetida was PNX dose-dependent. And the toxicity of all co-exposure groups was greater than that of the PNX only exposure groups. Furthermore, the addition of AgNPs significantly increased the damage of PNX on E. fetida intestinal tissue. Meanwhile, transcriptomic analysis showed that PNX + AgNPs had a greater effect on E. fetida than PNX single, and multiple pathways related to oxidative stress, inflammation, and cellular process regulation were disturbed. These results provide a basis for comprehensive evaluation of the ecotoxicity of PNX and confirm that the AgNPs does increase the ecotoxicity of PNX in soil environment.

Toxicity evaluation of chlorpyrifos and its main metabolite 3,5,6-trichloro-2-pyridinol (TCP) to Eisenia fetida in different soils.

The present study utilized a biomarker response method to evaluate the effect of 3,5,6-trichloro-2-pyridinol (TCP) in artificial and natural soils on Eisenia fetida after 7, 14, 28, 42 and 56 days exposure. Results indicated that TCP induced excessive reactive oxygen species, caused oxidative stress and DNA damage to Eisenia fetida. Biomarker responses were standardized to calculate the Integrated Biomarker Response (IBR) index. The IBR index of three enzymes (superoxide dismutase, catalase and glutathione S-transferase) activities showed that TCP induced the oxidative stress to E. fetida in red clay was stronger than in the other three soils. Specifically, chlorpyrifos exposure group showed a lower toxicity than TCP exposure group after 28 days exposure but a higher toxicity than TCP exposure group after 56 days exposure. Despite the deficiencies of this study, the above information is of great significance for assessing the risk of chlorpyrifos and its metabolite TCP pollution in soil ecosystems.

Polyhalogenated carbazoles (PHCZs) induce cardiotoxicity and behavioral changes in zebrafish at early developmental stages.

Polyhalogenated carbazoles (PHCZs) are widely present in the environment, and their health risks are of increasing concern. Available studies primarily confirm their dioxin-like toxicity mechanism based on biomarkers, such as aryl hydrocarbon receptor (AHR) and CYP1A1, while few studies have investigated their actual toxic effects at the level of individual organisms. In the present study, the developmental toxicity of two typical PHCZs with a high detection rate and high concentration in the environment (3,6-dichlorocarbazol (3,6-DCCZ) and 3,6-dibromocarbazole (3,6-DBCZ)) was investigated based on a fish embryo acute toxicity test (FET, zebrafish) and transcriptomics analysis. The 96 h LC50 values of 3,6-DCCZ and 3,6-DBCZ were 0.636 mg/L and 1.167 mg/L, respectively. Both tested PHCZs reduced the zebrafish heart rate and blocked heart looping at concentrations of 0.5 mg/L or higher. The swimming/escaping behavior of zebrafish larvae was more vulnerable to 3,6-DBCZ than 3,6-DCCZ. Transcriptomics assays showed that multiple pathways linked to organ development, immunization, metabolism and protein synthesis were disturbed in PHCZ-exposed fish, which might be the internal mechanism of the adverse effects. The present study provides evidence that PHCZs cause cardiac developmental toxicity and behavioral changes and improves our understanding of their health risks.

Toxicity evaluation of pyraclostrobin exposure in farmland soils and co-exposure with nZnO to Eisenia fetida.

Although the toxicity of pyraclostrobin (PYRA) to earthworms in artificial soil is well known, the toxicity of PYRA in farmland soils is yet to be explored in detail. Additionally, with more zinc oxide nanoparticles (nZnO) entering the soil environment, the risk of PYRA co-exposure with nZnO is increasing alarmingly. However, toxicity caused by this co-exposure of PYRA and nZnO is still unknown. Therefore, we assessed the biomarkers responses to reveal the toxicity of PYRA (0.1, 1, 2.5 mg/kg) on earthworms in farmland soils (black soil, fluvo-aquic soil, and red clay) and evaluated the biomarkers responses of Eisenia fetida exposed to PYRA (0.5 mg/kg)/PYRA+nZnO (10 mg/kg). Moreover, transcriptomic analysis was performed on E. fetida exposed to PYRA/PYRA+nZnO for 28 days to reveal the mechanism of genotoxicity. The Integrated Biomarker Responses (IBR) showed PYRA induced more severe oxidative stress and damage to E. fetida in farmland soils than that in artificial soil. The oxidative stress and damage induced by PYRA+nZnO were greater than that induced by PYRA. Transcriptomic analysis showed that PYRA and PYRA+nZnO significantly altered gene expression of both biological processes and molecular functions. These results provided toxicological data for PYRA exposure in three typical farmland soils and co-exposure with nZnO.

Ceftazidime-Avibactam in Combination with In Vitro Non-susceptible Antimicrobials Versus Ceftazidime-Avibactam in Monotherapy in Critically Ill Patients with Carbapenem-Resistant Klebsiella Pneumoniae Infection: A Retrospective Cohort Study.

BACKGROUND: No clinical study has investigated the use of ceftazidime-avibactam combination schemes with an in vitro non-susceptible antimicrobial that could be superior to ceftazidime-avibactam monotherapy against carbapenem-resistant Klebsiella pneumoniae. METHODS: We performed a retrospective cohort study at two tertiary hospitals in China for patients with carbapenem-resistant Klebsiella pneumoniae infection treated with ceftazidime-avibactam for at least 72 h. A Cox proportional hazards regression model was used to evaluate covariates that potentially affected 30-day mortality. RESULTS: Sixty-two patients were eligible for our study; 41 (66.1%) received ceftazidime-avibactam combination therapy and 21 (33.9%) received ceftazidime-avibactam monotherapy. The overall 30-day mortality was 33.9% (21 patients): 24.4% (10/41) and 47.6% (11/21), P = 0.028, in combination and monotherapy groups, respectively. Combination therapy was significantly associated with lower 30-day mortality (Hazard ratio, 0.167; 95% Confidence Interval, 0.060-0.465, P = 0.001). At the same time, a higher APACHE II score, use of vasoactive drugs and comorbidity of organ transplantation were considered factors that increased mortality. The propensity score showed no significant alterations with other variables after adding it to the final model. In the subgroup analysis, the protective effect was revealed when combined with carbapenems, tigecycline or fosfomycin were applied, and in the following subgroups of patients: with sepsis, with creatinine clearance > 50 mL/min, stayed in the intensive care unit ≤ 30 days or underwent mechanical ventilation. CONCLUSIONS: Ceftazidime-avibactam combined with another in vitro non-susceptible antimicrobial, especially carbapenems, fosfomycin and tigecycline, could significantly decrease the 30-day mortality rate for critically ill patients with carbapenem-resistant Klebsiella pneumoniae infection. Further investigation should be carried out to confirm this conclusion and identify autofit antimicrobials in ceftazidime-avibactam combination schemes.

Ecotoxicity evaluation of azoxystrobin on Eisenia fetida in different soils.

Azoxystrobin, a widely used broad-spectrum strobilurin fungicide, may pose a potential threat in agricultural ecosystems. To assess the ecological risk of azoxystrobin in real soil environments, we performed a study on the toxic effects of azoxystrobin on earthworms (Eisenia fetida) in three different natural soils (fluvo-aquic soil, black soil and red clay soil) and an artificial soil. Acute toxicity of azoxystrobin was determined by filter paper test and soil test. Accordingly, exposure concentrations of chronic toxicity were set at 0, 0.1, 1.0 and 2.5 mg kg-1. For chronic toxicity test, reactive oxygen species, activity of antioxidant enzymes (superoxide dismutase, catalase and peroxidase), detoxifying enzyme (glutathione transferase), level of lipid peroxidation (malondialdehyde) and level of oxygen damage of DNA (8-hydroxydeoxyguanosine) in earthworms were determined on the 7th, 14th, 21st, 28th, 42nd and 56th days after treatment. Both acute and chronic toxic results showed azoxystrobin exhibit higher toxicity in natural soil than in artificial soil, indicating that traditional artificial soil testing method underestimate ecotoxicity of azoxystrobin in a real agricultural environment on the earthworm population. Combining with the analysis of soil physicochemical properties, the present experiment provided scientific guidance for rational application of azoxystrobin in agricultural production systems.

Human Respiratory Monitoring Based on Schottky Resistance Humidity Sensors.

Two types of Schottky structure sensors (silicon nanowire (SiNW)/ZnO/reduced graphene oxide (rGO) and SiNW/TiO2/rGO) were designed, their humidity resistance characteristics were studied, and the sensors were applied to detect sleep apnea through breath humidity monitoring. The results show that the resistance of the sensors exhibited significant changes with increasing humidity, the response times of the two sensors within the relative humidity range of 23-97% were 49 s and 67 s, and the recovery times were 24 s and 43 s, respectively. Meanwhile, continuous breathing monitoring results indicate that the sensitivity of the sensors remained basically unchanged during 10 min of normal breathing and simulated apnea. The response of the sensor is still good after 30 days of use. We believe that the Schottky structure composite sensor is a very promising technology for human breathing monitoring.

Evaluating climate and irrigation effects on spatiotemporal variabilities of regional groundwater in an arid area using EOFs.

Groundwater level is an important variable in the evolution process of ecological environment systems. However, spatiotemporal changes in groundwater level are attributed to the comprehensive influence of natural and anthropogenic activities. Therefore, understanding the major driving forces to changes in spatiotemporal patterns of groundwater level is essential for sustainable utilization of regional groundwater and sustaining healthy ecosystems, especially in arid areas. In this study, based on monthly observations of depth to groundwater table (DTGT) from 67 monitoring wells during 2001-2010 in the Yichang Irrigation Sub-district (YISD) of the Hetao Irrigation District (HID), which is located in Northwest China with an arid climate, the empirical orthogonal function (EOF) method was used to analyze the spatiotemporal variations of DTGT and the major driving forces. The EOF analysis results showed that the first two spatial structures (EOF1 and EOF2) of DTGT were found in this region, which explained over 65% and 8% of the spatial variation of DTGT, respectively. Meteorological factors (evaporation and temperature) were the first leading factors to drive the temporal pattern of the first expansion coefficient (EC1) corresponding to the EOF1 at intra-annual scale as well as inter-annual scale. Particularly, temperature controlled the EC1 pattern during the freezing period from December to March. Soil texture was shown to have good correlations with the spatial patterns of DTGT, although these correlations diminished when the depth exceeded 250 cm. This study provides strong evidence that the principal spatiotemporal variations of groundwater can be effectively extracted by the EOF method, thereby obtaining integrated views of the relationships between the groundwater system and meteorological and anthropogenic factors.

Near-infrared tunable diode laser absorption spectroscopy-based determination of carbon dioxide in human exhaled breath.

A spectroscopic detection system for the accurate monitoring of carbon dioxide (CO2) in exhaled breath was realized by tunable diode laser absorption spectroscopy (TDLAS) in conjunction with a vertical-cavity surface-emitting laser (VCSEL) and a multipass cell with an effective optical path-length of 20 m. The VCSEL diode emitting light with an output power of 0.8 mW, covered the strong absorption line of CO2 at 6330.82 cm-1 by drive-current tuning. The minimum detectable concentration of 0.769‰ for CO2 detection was obtained, and a measurement precision of approximately 100 ppm was achieved with an integration time of 168 s. Real-time online measurements were carried out for the detection of CO2 expirograms from healthy subjects, different concentrations were obtained in dead space and alveolar gas. The exhaled CO2 increased significantly with the increasing physical activity, reaches its maximal value at the beginning of respiratory compensation and then decreased slightly until maximal exercise. The developed measurement system has a great potential to be applied in practice for the detection of pulmonary diseases associated with CO2 retention.

Evaluation of the toxicity of 1-butyl-3-methyl imidazolium tetrafluoroborate using earthworms (Eisenia fetida) in two soils.

Herein, to research the toxic effect of ionic liquids (ILs) on earthworms and compare their different toxicities in different soils, 1-butyl-3-methyl imidazolium tetrafluoroborate ([Bmim]BF4) was selected as a test substance, Eisenia fetida was selected as the experimental indicator organism, and artificial and fluvo-aquic soils were selected as the media. The acute toxicity, reactive oxygen species (ROS) content, detoxification enzyme (GST) activity, anti-oxidant enzyme activities, lipid peroxidation oxidative and DNA damage in earthworms were all measured to evaluate the toxicity of [Bmim]BF4. The results showed that either in fluvo-aquic soil or artificial soil, [Bmim]BF4 can stimulate the accumulation of ROS in earthworms, inducing activities of antioxidant enzymes and detoxification enzymes, inevitably causing lipid peroxidation and DNA damage in earthworms. The integrated biomarker response (IBR) indicated that the toxicity of [Bmim]BF4 in fluvo-aquic soil was greater than that in artificial soil. This experiment is relevant to the reliability of artificial soil toxicity research, and maybe this paper can provide a more authentic understanding of traditional toxicity experiments.