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Under stressful conditions, bacteria can enter viable but non-culturable (VBNC) state to survive. VBNC cells lost ability to grow on routine culture medium but are still alive and may revive in suitable conditions. The revived cells can consume nutrients or produce toxins, leading to food spoilage or human illness, posing great risk to food safety and public health. Previously, we have reported that high pressure carbon dioxide (HPCD), an environment-friendly sterilization technology, can induce VBNC formation. However, the underlying mechanism is unclear. By performing a comprehensive transcriptomic analysis, we revealed that HPCD initiated high expression of asr, encoding an acid shock protein, could promote VBNC formation of E. coli O157:H7. Quantitative reverse transcription PCR analysis suggested that high expression of asr (i) inhibited acid resistance (AR) systems, resulting in endogenous proton accumulation; (ii) inhibited hchA expression, a protein stabilizing factor. The two effects resulted in endogenous protein aggregation, which was highly correlated to VBNC formation. Accordingly, HPCD-stressed cells exhibited decreased efficiency of electron transfer chain and ATP production, which was also contributory to cytoplasmic protein aggregation. Taken together, HPCD-initiated high expression of Asr coupled with decreased ATP production led to protein aggregation, finally promoted the cells to enter VBNC state.

Bacterial spores can preserve cellular dormancy for years, but still hold the remarkable ability to revive and recommence life. This cellular awakening begins with a rapid and irreversible event termed germination; however, the metabolic determinants required for its success have been hardly explored. Here, we show that at the onset of the process of sporulation, the metabolic enzyme RocG catabolizes glutamate, facilitating ATP production in the spore progenitor cell, and subsequently influencing the eventual spore ATP reservoir. Mutants displaying low RocG levels generate low ATP-containing spores that exhibit severe germination deficiency. Importantly, this phenotype could be complemented by expressing RocG at a specific window of time during the initiation of sporulation. Thus, we propose that despite its low abundance in dormant spores, ATP energizes spore germination, and its production, fueled by RocG, is coupled with the initial developmental phase of spore formation.

High hydrostatic pressure (HHP) is currently the most successful non-thermal processing technology for commercial applications, but with a drawback that it is difficult to effectively inactivate the pectin methylesterase (PME), which is critical to the stability of orange juice. In this study, the PME inhibition and mechanism by HHP (600 MPa/10 min) combined with epigallocatechin gallate (HHP-EGCG) treatment were investigated. Firstly, the HHP-EGCG treatment showed enhancement effect on PME inhibition in orange juice, and the samples maintained higher content of water soluble pectin and exhibited higher suspension stability than the HHP treated samples during 13 days of refrigerated storage. Secondly, after HHP-EGCG treatment, further synergistic effect was observed in the phosphate buffer system, and the greatest secondary structure transformation and fluorescence quenching of PME occurred. Finally, molecule docking suggested that EGCG could interact with the active sites of PME, and transmission electron microscope results revealed further aggregation of PME under HHP-EGCG treatment.

Spores of wild-type Bacillus subtilis and some isogenic mutant strains were treated by high pressure CO2 (HPCD) at high temperature (HT) (HPCD + HT) at 20 MPa and 84-86 °C for 0–60 min, and centrifuged on a high density solution to obtain pelleted spores that retained CaDPA and light spores that lost CaDPA. All treated spores were analyzed for viability, and tested for germination, outgrowth, core protein damage, mutagenesis and inner membrane (IM) properties. The results showed that (i) with HPCD + HT treated spores, most pelleted spores and all light spores were dead; ii) a significant amount of dead HPCD + HT-treated spores that retained CaDPA germinated, but outgrowth was blocked; (iii) minimal mutants were generated in survivors of HPCD + HT treatment; (iv) the GFP fluorescence decrease in HPCD + HT-treated spores with high GFP levels was slower than spore inactivation; (v) the IM of HPCD + HT-treated spores that retained CaDPA lost its ability to retain CaDPA at 85 °C, and almost all of these spores' outgrowth in high salt was blocked; and (vi) HPCD + HT-treated spores that retained CaDPA germinated with l -valine or AGFK were almost all stained with propidium iodide. These results indicated that HPCD + HT inactivated B. subtilis spores by damaging spores’ IM, thus blocking spore outgrowth after germination.

The research on economic recession has been more focused on the interactions between macroeconomic and financial variables. However, whether material use has been affected during the recession period has remained under-explored. In order to fill up this gap, this study investigates the relationship between material use and economic recession, as well as other socio-economic drivers, by using the material flow analysis and the system generalized method of moments for 157 economies worldwide during 1980–2011. Results show that economic recession poses significant and negative impact on domestic material consumption at 1% level, illustrating its role as a determinant factor on material mitigation. By dividing the research sample into extractive and non-extractive economies, as well as high-, mid- and low-income groups, we again confirmed the significant negative correlations as expected. No significant sign is found between recession and physical trade balance. Besides, other drivers such as population, Gross Domestic Production (GDP) per capita and technological variables also exert marked effects at different situations. This research work provides an empirical study on how recession and other factors affect material use at various scenarios, which have essential implications for understanding material flow dynamics in different economic cycles.

Isocycloseram is a new isoxazoline insecticide that can efficiently control the diamondback moth in cruciferous crops. The aim of this study was to establish a method for the determination of isocycloseram residues in/on cabbage and in the soil using HPLC-UV at 264 nm. A field test was conducted in December 2019 and 2020 to monitor isocycloseram dissipation in Jiangxi, China. Acetonitrile was used to extract isocycloseram from cabbage and soil. C18 and GCB were used to purify cabbage extracts, whereas soil extracts did not require purification. At the addition level of 0.01–1.0 mg/kg, the average recoveries in cabbage and soil were 91.81–109.95% and 89.89–104.08% respectively. After having applied 10% isocycloseram DC, isocycloseram dissipated faster in the cabbage matrix. Isocycloseram residues on cabbage leaves could be removed through simple cleaning methods, especially by soaking in 2% citric acid.

The two essential terms in environmental sciences – dematerialization and decoupling – have always been controversial. This study aims to trace the evolution path on the methodologies, the evidence...

Revealing the spatio-temporal distribution of soil nitrogen (N) contributes to N management and prevention of N pollution. The objective of this work is to study the spatio-temporal distribution of soil N and their driving factors in the topsoil (0–20 cm) of farmland in Yugan county, China in 1982 and 2012. Data were collected from 200 sampling sites of the second national soil survey in Yugan in 1982 and 423 sampling sites of the soil testing and formula fertilization project in 2012. On average total N (TN) and available N (AN) significantly increased from 1.50 g kg−1 and 153.04 mg kg−1 in 1982 to 1.58 g kg−1 and 179.75 mg kg−1 in 2012, respectively. The distance of spatial autocorrelation for TN increased from 2.79 to 6.18 km and from 2.97 to 18.00 km for AN from 1982 to 2012. The nugget/sill ratio for TN (0.472 in 1982 and 0.581 in 2012) indicated that soil TN driving by natural characteristics in 1982 to human activities in 2012. The nugget/sill ratio for soil AN (0.471 in 1982 and 0.688 in 2012) indicated that soil AN is more influenced by human activities. The major factors driving the spatio-temporal distribution of soil N was N application rate. To promote the sustainable development of agriculture and eco-environment, we should improve the awareness of farmers on chemical fertilizers (particularly N) and the level of N fertilizer management, increase the use of manure and organic fertilizer and facilitate rational fertilization by farmers.

The effect of water activity (aw), as lowered by different dietary humectants, on the germination of Bacillus subtilis, Bacillus megaterium and Bacillus cereus spores with germinants that act by different mechanisms has been investigated and compared. Germination of spores of these species by all of the germinants investigated was inhibited as aw decreased, with the general order of efficacy for these non-ionic humectants being sucrose > trehalose > glycerol. The effect of lowering aw on germination by germinant receptor (GR)-dependent germinants was not appreciably altered by varying germinant concentrations, was generally not much more effective with spores lacking coats or an outer membrane, and was less pronounced with heat-activated spores. Analysis of the effect of aw on spore germination via different mechanisms showed that GR-dependent germination was least sensitive to aw, while germination via activation of spore cortex peptidoglycan hydrolysis or dipicolinic acid release was more sensitive. However, germination by high hydrostatic pressure was less sensitive to inhibition by low aw, than was germination by other germinants. Examination of the GR-dependent germination of individual spores indicated that aw acted most strongly in inhibiting the commitment step of germination, while exerting smaller effects on dipicolinic acid release or cortex peptidoglycan hydrolysis.

TiO2 films have received increasing attention for the removal of organic pollutants via photocatalysis. To develop a simple and effective method for improving the photodegradation efficiency of pollutants in surface water, we herein examined the preparation of a P25-TiO2 composite film on a cement substrate via a sol-gel method. In this case, Rhodamine B (RhB) was employed as the target organic pollutant. The self-generated TiO2 film and the P25-TiO2 composite film were characterized by X-ray diffraction (XRD), N2 adsorption/desorption measurements, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and diffuse reflectance spectroscopy (DRS). The photodegradation efficiencies of the two films were studied by RhB removal in water under UV (ultraviolet) irradiation. Over 4day exposure, the P25-TiO2 composite film exhibited higher photocatalytic performance than the self-generated TiO2 film. The photodegradation rate indicated that the efficiency of the P25-TiO2 composite film was enhanced by the addition of the rutile phase Degussa P25 powder. As such, cooperation between the anatase TiO2 and rutile P25 nanoparticles was beneficial for separation of the photo-induced electrons and holes. In addition, the influence of P25 doping on the P25-TiO2 composite films was evaluated. We found that up to a certain saturation point, increased doping enhanced the photodegradation ability of the composite film. Thus, we herein demonstrated that the doping of P25 powders is a simple but effective strategy to prepare a P25-TiO2 composite film on a cement substrate, and the resulting film exhibits excellent removal efficiency in the degradation of organic pollutants.

Rice weeds strongly inhibit the production of rice because they compete with rice. Glyamifop is a novel herbicide for controlling rice weeds and being tested in paddy fields. Based on our previous studies, Glyamifop offers excellent control for rice weeds and has no negative effects on rice plant growth as well as rice yields. However, the adsorption–desorption and migration behaviors of Glyamifop in paddy soils are still not well resolved. In this study, we investigated the adsorption–desorption and migration characteristics of Glyamifop in paddy soils collected from four provinces in China, using batch equilibrium, soil column leaching, and thin-layer chromatography tests combined with liquid chromatography–tandem mass spectrometry (LC-MS) analysis. The results showed that all the soils had a relatively high adsorption capacity for Glyamifop, and both Freundlich adsorption and desorption constants were positively correlated with soil cation exchange capacity, organic carbon content, and organic matter content (P

Gearbox fault diagnosis plays an irreplaceable role in ensuring the safe operation of rotating machinery equipment. However, many researches have only diagnosed single faults, and have not detected single faults from compound faults of gearbox. Therefore, in this paper, a framework based on random forest hybrid classifier (RFHC) is proposed for single fault detection, which not only identifies various fault types, but also separates the single fault from compound faults. Meanwhile, an improved Dempster–Shafer (IDS) information fusion method is developed to fuse the result obtained by the hybrid classifier. Extensive evaluations of the proposed methods on the QPZZ-II experimental platform datasets showed that the proposed framework detects the single faults from the compound faults effectively, which reduces the categorization complexity of a single classifier and improves the overall performance of the detection framework. Moreover, compared with the diagnosis result of a single sensor, IDS can achieve higher average fusion precision and improve the reliability of gearbox single fault detection.

In this work, it has firstly found that carbon-doped boron nitride (BCN) material has high affinity for proton and can be used as pH-responsive material to selectively recover protonated dyes neutral red (NR) and malachite green (MG) from dye wastewater. The maximum adsorption capacities of BCN for NR and MG are 747.10 mg·g−1 and 682.46 mg·g−1 which is obviously larger than that of methyl orange (MO 61.27 mg·g−1) and methylene blue (MB 119.38 mg·g−1). The adsorbed protonated dyes are easily released through pH changeing and the maximum recovery amounts of NR and MG are 704.94 mg·g−1 and 631.54 mg·g−1, respectively. The effects of inorganic ions (Cl−, SO42− and NO3−) and cationic surfactant on the adsorption performance of BCN to NR and MG can be negligible. By the adding of anionic surfactant, the adsorption and release performance of BCN to NR and MG is a little decrease. BCN can still selectively recover NR (or MG) from the mixed dye solutions. In two mixed dye solutions, the maximum recovery of BCN for NR (or MG) is above 90.93%. In ternary system, the maximum recovery of BCN for protonated dye is above 79.21%. In NR-MG-MB-MO quaternary system, the recovery of BCN for NR and MG is above 87.57%. Therefore, BCN has a good potential that is used to selectively recover the protonated dyes from dye wastewater.

Twenty colonies of Pediococcus acidilactici, Lactobacillus brevis, Lactiplantibacillus plantarum and Latilactobacillus curvatus were isolated from fermentation broth of pickled pepper by using MRS agar. The strains were acclimated using high pressure from 300 to 400 MPa for 1 to 5 min. For one generation of acclimation, the survived cells after first high pressure treatment were then activated by culturing on MRS agar for two days for the next high pressure treatment. After acclimation for 30 generations, the survival ratio of L. plantarum and L. curvatus was increased by 138 and 1222 times at 400 MPa for 1 and 3 min, respectively. Weibull model could appropriately fit the survival curves of L. plantarum and L. curvatus treated by high pressure. The time to the first decimal reduction of these two strains after acclimation was 3.5 and 1.8 times, respectively, longer than before acclimation at 300 MPa. From electron microscopy photographs, the acclimated L. curvatus was more curved, smaller and its cell wall was thicker than the unacclimated L. curvatus. After HPP treatment, L. plantarum and L. curvatus have higher cell integrity, smoother cell surface, more uniform protoplasm and smaller cavities in the cell protoplasm compared with unacclimated strains, suggesting that high pressure acclimation introduced some modification to bacteria intrinsic structures and increased their pressure resistance. Moreover, the fermentation performance including glucose utilization capacity and lactic acid production of the acclimated L. curvatus was respectively improved by 9.6% and 9.4% at 37 °C for 24 h in MRS medium.

Semiconductor photocatalysis is as a promising method for water pollution remediation. However, the recycling and light capture of powder photocatalysts in traditional suspension systems are bottlenecks for their practical application in photocatalysis. Moreover, the large-scale application of traditional immobilized photocatalytic systems immersed in solution is limited due to the electron-hole recombination and slow reaction rate. Herein, we have successfully prepared superhydrophobic self-floating TiO2-silicone composite aerogels by condensation polymerization of γ-methacryloxypropyl trimethoxysilane (KH570) modified anatase TiO2 and methyltriethoxysilane (MTES). The air–liquid-solid triphase photocatalytic system was constructed using the air layer formed by the superhydrophobic self-floating composite aerogel and the solution interface, which solved the above-mentioned limitation. The floating characteristics of the system effectively avoided the absorption of light by the solution, thereby significantly enhancing the light utilization of the catalyst. The air–liquid-solid interface allows oxygen to be quickly transported from the air to the reaction interface, and oxygen, which is a natural electron scavenger, can effectively remove photoelectrons from the catalyst surface and the recombination of electron-holes is minimized. The new self-floating photocatalyst with triphase catalytic system presented high practical application value for the degradation of suspended pollutants in a natural environment.

First-principles calculations was used to explore the influence of atom termination and stacking sequence on the interface strength and stability between θ′(Al 2 Cu) precipitate and Al matrix along experimentally observed orientations, (001)θ′/(001)Al and (010)θ′/(010)Al interfaces. Six interfacial structures were modeled, and work of adhesion, bonding characters, number of valence electrons and thermal stability had been studied. Calculated results revealed that the Cu-terminated interface has larger work of adhesion than Al-terminated interface, and hollow site stacking sequence, with stronger bonding, is superior to top site stacking sequence, adhesion strength for coherent (001)θ′/(001)Al interface is better than that for semi-coherent (010)θ′/(010)Al interface. These differences are attributed to the bonding feature and number of valence electrons. Among the six interface models, the Cu-terminated (001)θ′/(001)Al interface with hollow site stacking has the largest work of adhesion and the smallest interface energy, indicating that it has the best mechanical and thermodynamic properties.

Glyamifop is a new herbicide developed by Jiangsu Zhongqi Technology Co., Ltd. (Nanjing, China). No analytical method has previously been reported for determining its residual concentrations in rice and its related environmental samples. This work established a method for the determination of Glyamifop residues in various matrices using high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS) with sample pretreatment by the optimized quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. All samples were extracted with acetonitrile and purified with octadecyl bonded silica gel, N-propylethylenediamine, and graphitized carbon black adsorbents. Chromatographic separation was performed on an Agilen ZORBAX Eclipse XDB-C18 column, and Glyamifop in the samples was detected by electrospray ionization mass spectrometry in positive ion mode. Results demonstrated this method has good linearity for Glyamifop assessment in all matrices over a wide concentration range (0.01–1 mg L−1), with a coefficient of determination >0.99. At levels of 0.01, 0.1, and 0.5 mg kg−1, the mean recoveries of Glyamifop in various matrices varied between 84.15% and 105.76%, with relative standard deviations of 1.3%–9.8%. The detection and quantification limits of this method in each matrix are 1.3–3.6 μg kg−1 and 4.89–12.48 μg kg−1, respectively. All matrices had a moderate matrix effect (between −21.63% and 14.21%), which could be calibrated using respective matrix standard curves. The proposed method is simple and sensitive, and appears suitable for the determination of Glyamifop residues in rice and its environment.

Benzobicyclon is a systemic herbicide that was officially registered in China in 2018. The environmental behaviors of benzobicyclon hydrolysate (BH), the main metabolite and active product of benzobicyclon, remain poorly understood in paddy fields. Here, agricultural soil samples were collected from paddy fields in Jiangxi (Ferralsols), Shandong (Alisols), Hebei (Luvisols), Heilongjiang (Phaeozems), Zhejiang (Anthrosols), Sichuan (Gleysols), Hainan (Plinthosols), and Hubei (Lixisols) across China. The equilibrium oscillation method was used to study the adsorption–desorption behaviors of BH in the eight soils. The relationships between BH adsorption and soil physicochemical properties, environmental factors (temperature and initial solution pH), and other external conditions (addition of humic acid, biochar, and metal ions) were quantified. The adsorption–desorption parameters of BH in all soils were well fitted by the Freundlich model. The adsorption constant of BH varied between 0.066 and 4.728. The BH adsorption capacity decreased in the following order: Phaeozems > Alisols > Ferralsols > Lixisols > Plinthosols > Anthrosols > Luvisols > Gleysols. The Freundlich adsorption and desorption constants of BH were linearly positively correlated with soil clay content (R2 = 0.711 and 0.709; P = 0.009 and 0.009, respectively), organic carbon content (R2 = 0.684 and 0.672; P = 0.011 and 0.013, respectively), and organic matter content (R2 = 0.698 and 0.683; P = 0.010 and 0.011, respectively); however, their linear relationships with soil cation exchange capacity were not significant (R2 = 0.192 and 0.192; P = 0.278 and 0.278, respectively). The adsorption and desorption constants of BH had negative, albeit not significant, correlations with soil pH (R2 = 0.104 and 0.100; P = 0.437 and 0.445, respectively). The adsorption of BH by soil occurred spontaneously and was mainly based on physical adsorption. Either low or high temperature reduced the ability of the soil to adsorb BH. The addition of humic acid to the soil increased BH adsorption, while the addition of biochar increased the solution pH, resulting in decreased BH adsorption. Cation type and ionic strength also had strong effects on BH adsorption. With the exception of Phaeozems, BH exhibited intermediate or high mobility in the agricultural soils and thus poses risks to surface water and groundwater.

Escherichia coli O157:H7, the causative agent of haemorrhagic colitis and haemolytic uremic syndrome in humans, has been implicated in large food-borne outbreaks all over the world. When confronted with harsh environmental stresses, it can enter into a viable but nonculturable (VBNC) state, which poses a great risk to food safety and public health since conventional methods are invalid to detect VBNC cells. Herein, a system for detecting VBNC state Escherichia coli O157:H7 was established by combining droplet digital PCR (ddPCR) with propidium monoazide (PMA). This system took advantage of an absolute quantification without external calibration of ddPCR and DNA binding, modification capacity of PMA after penetrating into compromised cells, providing a sensitive detection limit of 5 copies/μL, good accuracy and specificity. The PMA-ddPCR platform could be applied not only on detection of VBNC cells induced by non-thermal pasteurization technique, high pressure CO2 (HPCD), but also quantification of viable E. coli O157:H7 in food samples including prawn, squid, lettuce and pear juice. Taken together, our research provides an effective method for detecting VBNC pathogenic bacteria during food pasteurization process or in food samples.

A series of carbon-doped boron nitride (BCN) are synthesized via oxygen-limited method, in which BCN-0.6 has the best adsorption quantity for tetracycline (TC). BCN-0.6 can capture protons and increase the pH of TC solution from 3.80 to 7.87, which makes that TC changes to negative state (pH 7.87) from neutral state (pH 3.80). BCN-0.6 exists in protonated form in solution. TC adsorption quantity by BCN-0.6 in pH 7.87 is higher than that in pH 3.8 (76.74 mg·g-1 vs. 63.08 mg·g-1), being due to that these captured protons can also interact with these oxygen-containing groups in TC via hydrogen bonding. The hydroxyl numbers of BCN-0.6 have been determined via Boehm titration method for clarifying the contribution of these surface hydroxyl for TC adsorption. In addition, some of the captured protons by BCN-0.6 can transfer to TC during adsorption process, increasing the electrostatic interaction between BCN-0.6 and TC. Experimental and theoretical studies support that hydrogen bonding, electrostatic interaction and π…π stacking are main driving force for TC adsorption by BCN-0.6. Langmuir isotherm model and pseudo-second-order kinetic model are suitable to describe the adsorption of TC by BCN-0.6. And, this adsorption is an endothermic process. The adsorption performance of BCN-0.6 for TC is easily regenerated by washing with water. Furthermore, the per unit specific surface adsorption capacity (4.102 mg·m-2) of BCN-0.6 for TC is far higher than that of commercial activated carbon for TC (0.163 mg·m-2), suggesting that BCN-0.6 is a good adsorbent for water purification.

Spores of wild-type Bacillus subtilis PS533 were treated by wet heat at 75 °C for 30 min, and high pressure CO2 (HPCD) at 6.5 MPa and 30 °C or 75 °C for 30 min. The spores were analyzed for wet heat resistance (85 °C, 90 °C, 95 °C) and typical germination events including DPA release and cortex hydrolysis, inner membrane permeability, and germination triggered by nutrient (L-valine and AGFK) or non-nutrient (dodecylamine and high pressure at 150 MPa or 550 MPa) germinants. The results showed that (i) HPCD-treated spores exhibited reduced wet heat resistance compared to the untreated or wet heat-treated spores; (ii) HPCD-treated spores did not undergo typical germination events such as DPA release or cortex hydrolysis compared to normally germinated spores; (iii) HPCD-treated spores released more metal ions and exhibited decreased ability to maintain DPA, indicating that the permeability of inner membrane of HPCD-treated spores was increased; (iv) HPCD-treated spores exhibited reduced germination rate when triggered by L-valine or 150 MPa, but increased germination rate when triggered by dodecylamine or 550 MPa, suggesting that the fluidity of the inner membrane of HPCD-treated spores might be increased. These results indicated that HPCD could reduce the wet heat resistance of spores, and this resistance decrease was probably due to the modification of the inner membrane caused by HPCD. Industrial relevance The extremely high wet heat resistance of spores makes them a significant problem in the thermal processing of foods. Thus, it of great interest to develop a process to reduce the wet heat resistance of spores. In this work, we found that HPCD can significantly reduce the wet heat resistance of B. subtilis spores, and this was achieved by perturbing the inner membrane of spores. These results can improve our understanding of the inactivation mechanism of spores by HPCD, and also provide an alternative approach for spore inactivation in foods.

The photocatalytic activity of graphitic carbon nitride (g-C3N4) is restricted by its inherent shortcomings. Nitrogen (N) vacancies and crystallinity are two effective options to enhance the photocatalytic activity of g-C3N4. In this paper, oxalyl dihydrazide (ODH) was introduced as an environmental atmosphere control agent for the synthesis of N vacancies g-C3N4 with increased crystallinity. The increased crystallinity and N vacancies can effectively contribute to interlayer and intralayer exciton dissociation and charge transfer, respectively. They can modulate electronic band structure to boost visible light harvesting. The obtained visible-light (λ > 420 nm) photocatalytic efficiency of ODH-CN2 for tetracycline hydrochloride (TC-HCl) and sulfamethoxazole (SMZ) degradation was 79.9% (60 min) and 91.5% (120 min), respectively. These results are 39.8% and 36.7% higher than that of traditional g-C3N4 (CN), respectively. Moreover the visible-light photocatalytic H2 evolution rate of ODH-CN2 in triethanolamine solution with 3% Pt reached 5833.1 μmol h−1 g−1, approximately 4 times higher than that of CN. Subsequently, TC-HCl or SMZ were used as hole sacrificial agents to realize simultaneous H2 evolution and degradation of TC-HCl or SMZ over ODH-CN2 with 3% Pt. This study proposes promoting the photocatalytic activity of g-C3N4 by using an environmental atmosphere control agent to simultaneously form N vacancies and increase crystallinity, thus accelerating interlayer and intralayer exciton dissociation and charge transfer, respectively.

In this study, N-TiO2/O-doped N vacancy g-C3N4 was synthesized by the solvothermal method. The optimized photocatalyst N-TiO2/CNONV-2 has excellent photocatalytic activity, and it can reach about 3 times of tetracycline hydrochloride (TC−HCl) degradation rate and 41 times of Cr(VI) reduction rate comparing with N vacancy g-C3N4. Meanwhile, N-TiO2/CNONV-2 exhibited excellent photocatalytic activity and chemical stability under TC−HCl and Cr(VI) coexistence environment. The enhancement photocatalytic activity mechanism of N-TiO2/CNONV-2 is that Z-scheme heterojunctions accelerate the separation of electrons and holes, while mainly O2– and h+ attack TC−HCl and e– reduces Cr(VI) under TC−HCl and Cr(VI) coexistence environment. The influence of environmental factors (pH, organic matter, and inorganic salt) on the photocatalytic activity of N-TiO2/CNONV-2 under TC−HCl and Cr(VI) coexistence environment was studied. Furthermore, the toxicity of the intermediates was evaluated by quantitative structure-activity relationship (QSAR) prediction. The results demonstrated that the toxicity of TC intermediates can be degraded into low level over N-TiO2/CNONV-2.

Under the generalized gradient approximation (GGA), the structural and electronic properties are studied for both zigzag (ZAlNNRs) and armchair (AAlNNRs) AlN nanoribbons terminated with H atoms at both edges by using the first-principles projector-augmented wave (PAW) potential within the density function theory (DFT) framework. The results show that the Al–N, Al–C and Al–H bonds are ionic bonds while the C–C and C–H bonds are typical covalent bonds, and the N–C and N–H bonds have a degree covalent character. The systems of both perfect 7-ZAlNNR and perfect 7-AAlNNR with a single C-chain doped are still nonmagnetic semiconductors, and the C-chain reduces the band gap. The C-chain can change the band gap of 7-ZAlNNR from direct to indirect independent of the position of the C-chain, which is important in the practical application as light emitting devices. For N Z -ZAlNNR-C( n ) with N Z = 3, 5, 6, 10, the band gap decrease successively for C-chain position n from 2 to 3, 5, 6, 7 and 10, respectively. For N A -AAlNNR-C( n ) of arbitrary width N A , except N A -AAlNNR-C(1) and N A -AAlNNR-C( n = N A ) have a larger band gap, the band gap of the rest of the N A -AAlNNR-C( n ) are about 2.0 eV. Furthermore, the maximum band gap gradually decrease with the increase of the width N A . The C-chain substituting Al–N chain process is endothermic for both 7-ZAlNNR and 7-AAlNNR.

The objective of this study was to investigate the inactivation of the Bacillus subtilis spores by high pressure CO 2 combined with high temperature (HPCD + HT) and to analyze the clumping effect of the spores on their HPCD + HT resistance. The spores of B . subtilis were subjected to heat at 0.1 MPa and HPCD at 6.5–25 MPa, and 82 °C, 86 °C, and 91 °C for 0–120 min. The spores were effectively inactivated by HPCD + HT, but a protective effect on the spores was also found, which was closely correlated to the pressure, temperature and time. The spores treated by HPCD + HT at 6.5 and 10 MPa exhibited a two-stage inactivation curve of shoulder and log-linear regions whereas the spores at 15–25 MPa exhibited a three-stage inactivation curve of shoulder, log-linear and tailing regions, and these curves were well fitted to the Geeraerd model. Approximately 90% of pyridine-2,6-dicarboxylic acid (DPA) was released after HPCD + HT and the 90% DPA release time depend on the pressure and temperature. Moreover, the spore clumping in suspensions was examined by dynamic light scattering. The particle size of the spore suspensions increased with the increase of pressure, temperature and time, indicating the spore clumping. 0.1% Tween 80 as a surfactant inhibited the spore clumping and increased the inactivation ratio of the spores by HPCD + HT. These results indicated that the spore clumping enhanced the spores' resistance to HPCD + HT and induced a protective effect.

Automobile manufacturers are delivering a new generation of connected vehicles with in-cabin Wi-Fi devices, enabling advances in a wide range of in-vehicle communications and infotainment capabilities. The communication performance is a key factor enabling the instant multimedia streaming. A fundamental question remains to be explored: as every running vehicle is equipped with an in-cabin Wi-Fi, how will be the communication performance affected by the varied number of surrounding vehicles, the transmission power and the data rate? In order to answer this question, we establish analytical models that embody the novel in-cabin Wi-Fi features. We set up a new evaluation platform for in-cabin Wi-Fi communications based on extensive simulations. We report how the performance of in-cabin Wi-Fi communications is affected by traffic conditions and Wi-Fi hotspot settings. Through extensive analysis and evaluations, we show how to configure the in-cabin Wi-Fi to guarantee the quality of service.

Graphical abstract: Graphene/ZnWO{sub 4} (G–ZnWO{sub 4}) nanorod composite photocatalysts were prepared by a simple one-step method. Namely, the reduction of graphene oxide and the growth of ZnWO{sub 4} nanorod occurred simultaneously in one single process. An enhancement in the photocatalytic activities were observed in G–ZnWO{sub 4} composites compared with pure ZnWO{sub 4} under UV light irradiation. - Highlights: • Graphene–ZnWO{sub 4} composite photocatalyst was prepared for the first time. • The as-prepared composite photocatalysts show high activity for dye degradation. • Effect of graphene amount on the photocatalytic activity was investigated. - Abstract: Graphene–zinc tungstate (G–ZnWO{sub 4}) hybrid photocatalysts were prepared by an in-situ growth method in which the reduction of graphene oxide (GO) and the growth of ZnWO{sub 4} crystals occurred simultaneously. The materials were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV–vis diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. The photocatalytic activity was investigated by the degradation of dye methylene blue (MB). An enhancement in the photocatalytic activity was observed for G–ZnWO{sub 4} hybrids compared with pure ZnWO{sub 4} under UV light. This improvement was attributed to the following two reasons: increased migration efficiency of photo-induced electrons and increased adsorption activity for dye molecules. Themore » effect of the amount of graphene on the photocatalytic activity was also investigated. Results showed that there was an optimum amount of 2%.« less

The individual and combined effects of high pressure carbon dioxide (HPCD) and nisin (200 IU/mL) on the inactivation of Escherichia coli O157:H7 suspended in physiological saline (PS, pH 5.60), phosphate-buffered saline (PBS, pH 5.60 or 7.00) or carrot juice (pH 6.80) were evaluated. The pressure in this study was 5 and 8 MPa, the temperature was 25 °C–45 °C, and the treatment time was 5–65 min. Inactivation of cells in PS (pH 5.60) by HPCD followed first order kinetics, the k (the inactivation rates) increased while the D (decimal reduction time) decreased in the presence of nisin, however, the acid solution dissolving nisin rather than nisin itself played a prominent role in this combination effect with HPCD in PS buffer. The inactivation kinetics of cells in PBS (pH 5.60 or 7.00) and carrot juice (pH 6.80) by HPCD followed slow-to-fast two-stage kinetics and was fitted by the modified Gompertz equation. The M (the time at which the absolute death rate is maximum) significantly decreased in the presence of nisin. HPCD enhanced the sensitization of E. coli to nisin and the time for the complete inactivation was shortened by 2.5–5 min in PBS buffer and carrot juice by combination of HPCD and nisin (HPCD + nisin) than by HPCD alone. Regression coefficients (R2) and mean square error (MSE) were used to evaluate the model performance, indicating that the models could provide a good fitting to the experimental data.

The aim of the present work is to examine whether the price volatility of nonferrous metal futures can be used to predict the aggregate stock market returns in China. During a sample period from January of 2004 to December of 2011, empirical results show that the price volatility of basic nonferrous metals is a good predictor of value-weighted stock portfolio at various horizons in both in-sample and out-of-sample regressions. The predictive power of metal copper volatility is greater than that of aluminum. The results are robust to alternative measurements of variables and econometric approaches. After controlling several well-known macro pricing variables, the predictive power of copper volatility declines but remains statistically significant. Since the predictability exists only during our sample period, we conjecture that the stock market predictability by metal price volatility is partly driven by commodity financialization.

The performance of AlGaN deep ultraviolet(UV) light emitting diodes(LEDs) has been limited by the extremely low light extraction efficiency(LEE), which is due to the severe light absorption by metal electrode and unique transverse magnetic polarization. Here, we propose an ordered nanowire array structure UV-LEDs with transparent graphene electrode. By using the finite-difference time domain simulation, the relationship between LEE and different nanowire structures (including ordered and disordered nanowires array) was studied. We demonstrate that ordered nanowire arrays are better than disordered nanowires in improving the LEE. A high LEE about 80% can, in principle, be expected from top surface with optimized nanowire radius and spacing. In addition, by studying the distribution of electric field intensity on the side and top of UV-LEDs with graphene electrode and Ni/Au electrode, we show that the graphene electrode can reduce the absorption of ultraviolet light and improve LEE more effectively than the conventional Ni/Au electrode. This proposed structure could be a promising candidate for high light extraction efficiency UV-LEDs.

Effects of electric field strength (0–35 kV/cm) and pulse rise time (PRT) of 2 μs and 0.2 μs during pulsed electric fields (PEF) on enzymatic activity, vitamin C, total phenols, antioxidant capacities, color and rheological characteristics of fresh apple juice were investigated. With increasing the electric field strength and PRT, the residual activity (RA) of polyphenoloxidase (PPO) and peroxidase (POD) decreased, almost complete inactivation of both enzymes was achieved at 35 kV/cm and 2 μs-PRT. The content of vitamin C in apple juice decreased significantly (p

Ultra-high pressure (UHP) was applied for pectin extraction from navel orange peel. The effects of pressure, temperature and pressure-holding time on the extraction yield and viscosity of pectin were investigated. A 2-factor 3-level design, following a single-factor experiment, was carried out to optimize the extraction parameters and the optimal conditions of UHP extraction were determined as pressure 500 MPa, temperature 55 °C, pressure-holding time 10 min. Under the optimal conditions, the yield of pectin (20.44% ± 0.64) was significantly higher than those extracted by traditional heating (15.47% ± 0.26) and microwave (18.13% ± 0.23). The physicochemical properties and rheological characteristics of pectin extracted by ultra-high pressure, traditional heating and microwave as well as commercial pectin were also compared. The results showed that the intrinsic viscosity and viscosity-average molecular weight of pectin extracted by UHP (0.7604 L/g and 3.063 × 10 5 Da) were much higher than those extracted by traditional heating (0.4276 L/g and 1.521 × 10 5 Da), microwave (0.3591 L/g and 1.230 × 10 5 Da), and the commercial pectin (0.2160 L/g and 0.663 × 10 5 Da). The same results were also obtained in the rheological characteristics, activation energy and gelling properties determination. These results clearly demonstrated that UHP is a more efficient, time saving, and eco-friendly alternative for pectin extraction from navel orange peel, especially for pectin with higher viscosity and stability.

In this paper, a novel double-clad photonic crystal fiber (DC-PCF) is proposed for achieving both high birefringence and low leakage loss. According to numerical simulation of the proposed PCF, the extraordinarily high birefringence (over 2×10−2) and low leakage loss of the order of 0.0001 dB/km over a large wavelength range are achieved simultaneously. Single-polarization single-mode (SPSM) operation with low leakage loss is also discussed and can be realized and optimized in the PCF by adopting suitable structure parameters.

High field magnetization measurements (up to 38 T) were carried out at 4.2 K on “free powder” samples from Dy 2 Fe 17− x Ga x ( x =5–8) compounds. The data were used to evaluate the microscopic exchange parameter, J DyFe . Its value was also obtained by mean-field analysis of Curie temperatures, T c , in agreement with the high-field data. The obtained results reveal an increase of J DyFe above x =6 that can be correlated with the observed change in T c vs. x for Dy 2 Fe 17− x Ga x compounds and their counterparts with Y.

This paper is a review of the research that has been performed on the development and applications of a non-radioactive electron-capture detector (ECD). The ionization in the ECD, normally supplied by a radioactive foil, is supplied by the electromagnetic radiation emanating from a high voltage pulsed discharge in pure helium. This emission consists of a broad band in the vicinity of 13.5–17.5 eV. This is a well know emission arising from a transition in an excited He2 molecule to a dissociative ground state. The importance of having a high energy process to initiate the ionization in an ECD is emphasized and is the principal reason why the non-radioactive ECD performs in a similar manner to the radioactive ECD. The principal advantage of the non-radioactive ECD is the cleanliness of the detector since the gas chromatography (GC) column effluent does not come in contact with the ionization source. Most radioactive ECDs generally pass the GC column effluent directly over the radioactive foil where the electrons are produced from the emission. Furthermore, the internal volume of the non-radioactive ECD can be made smaller than that of radioactive ECD using 63Ni foils. For this reason, lower make-up gas flow-rates can be used and the sensitivity of the non-radioactive ECD is slightly greater than that for radioactive ECD. The temperature dependence of the non-radioactive ECD closely parallels that of the radioactive detector. This similar behavior is the most definitive criterion that the detectors operate in a similar manner, displaying the different types of electron attachment mechanisms. Applications to the analysis of pesticides, polychlorinated biphenyls and metal complexes have been demonstrated along with their temperature dependence.

The Sm2Fe17Ny nitrides with nitrogen concentration y = 2 to 8 have been prepared using a mixed gas atmosphere of NH3 and H-2. Their intrinsic magnetic properties were studied at 1.5 and 293 K. The Th2Zn17-type structure is maintained when y is less than 6. The 9e sites can be fully occupied and the 18g sites may be half occupied by nitrogen atoms. The nitrogen at the 9e sites and 18g sites have a positive effect and a negative effect, respectively, on the intrinsic magnetic properties of Sm2Fe17 compound. The nitride Sm2Fe17N3 has the best intrinsic magnetic properties.

The thermal stability, structural and magnetic properties of Sm 2 (Fe 1− x M x ) 17 N y nitrides (M = Co, Ni, Al, Ti and V) have been investigated. The Curie temperature increases with Co concentration but decreases with Ni or Al concentration. The saturation magnetization M s and the anisotropy field B a at room temperature of Sm 2 (Fe 1 - x Co x ) 17 N y both reach their maxima of 147 J/T kg and 15.5 T respectively. All nitrides start to decompose at a similar temperature of ≈ 650°C.

Isotropic Sm 2 Fe 17 N y powder was prepared by ball-milling from the parent alloy of Sm 2 Fe 17 , subsequent nitriding. The room-temperature coercivity up to 31.3 kOe was acheived. The maximum energy product was derived to be 10.5 MGOe with a remanence of 7.0 kGs. The anisotropy field H a of this nitride is 180 kOe determined by SPD technique.

Hydrogen decrepitation of Sm 2 Fe 17 followed by treatment in ammonia produces interstitial nitrides with nitrogen concentrations greater than three per formula unit. Measurements of the lattice parameters and magnetic properties are consistent with interstitial nitrogen occupation of the 9e and either the 3b or 18g sites. The effect of the extra nitrogen on the iron sublattice is to reduce the overall moment, particularly of the 18h sites. The magnetocrystalline anisotropy constants K 1 and K 2 indicate a significant decrease in the easy-axis character compared to Sm 2 Fe 17 N 3 material.

Magnetization measurements at 4.2 K on polycrystalline ErNi 2 B 2 C show 70% of perfect flux exclusion. A metamagnetic transition occurs at 1.6 T with ΔM ∼ 3 μ B /f.u. Magnetization in 5 T is 5.7 μ B /f.u., less than expected for free Er 3+ ions. A crystal field calculation with the point charge model confirms an easy plane ground state |M J = ± 1 2 〉 . The in-plane anisotropy K ′ 2 is −10 5 J/m 3 .