Adsorption of Cd2+ by Lactobacillus plantarum Immobilized on Distiller's Grains Biochar: Mechanism and Action.

Immobilized microbial technology has recently emerged as a prominent research focus for the remediation of heavy metal pollution because of its superior treatment efficiency, ease of operation, environmental friendliness, and cost-effectiveness. This study investigated the adsorption characteristics and mechanisms of Cd2+ solutions by Lactobacillus plantarum adsorbed immobilized on distiller's grains biochar (XIM) and Lactobacillus plantarum-encapsulated immobilized on distiller's grains biochar (BIM). The findings reveal that the maximum adsorption capacity and efficiency were achieved at a pH solution of 6.0. Specifically, at an adsorption equilibrium concentration of cadmium at 60 mg/L, XIM and BIM had adsorption capacities of 8.40 ± 0.30 mg/g and 12.23 ± 0.05 mg/g, respectively. BIM demonstrated noticeably greater adsorption capacities than XIM at various cadmium solution concentrations. A combination of isothermal adsorption modeling, kinetic modeling, scanning electron microscopy-energy dispersive X-ray spectroscopy, X-ray diffractometer (XRD), and Fourier-transform infrared spectroscopy (FTIR) analyses showed that cadmium adsorption by XIM primarily involved physical adsorption and pore retention. In contrast, the adsorption mechanism of BIM was mainly attributed to the formation of Cd(CN)2 crystals.

[Summer Ozone Mechanism and Control Strategy in Beijing-Tianjin-Hebei Region Using Brute-Force Method].

In recent years, the ozone (O3) volume fraction in the Beijing-Tianjin-Hebei Region in summer have remained high, light to moderate pollution occurs frequently, and research on related response mechanisms is urgently needed. This study applied the WRF-Chem model to simulate the change in ozone volume fraction in this region by setting 13 precursor emission scenarios in a representative month in the summer of 2018. The results revealed that VOC-sensitivity and no-sensitivity regimes commonly occurred in the Beijing-Tianjin-Hebei Region in July, and the VOC-sensitivity regimes were mainly accumulated in the central Beijing-Tianjin-Hebei Region, with a north-to-south zonal distribution and an area share of 15.60%-26.59%. The relative response intensity (RRI) of O3 volume fraction to precursor emissions in urban areas had large spatial variability, with RRI_VOC and RRI_NOx in the ranges of 0.03-0.16 and -0.40-0.03, respectively. The higher the latitude of urban areas, the more dramatic were the RRI values, indicating a more significant regional transport influence. The lower RRI_NOx values in urban areas with high intensity of precursor emissions implied a negative dependence of RRI_NOx on local NO2 concentrations; however, RRI_VOC was not significantly correlated with NO2levels and was more dependent on the relative abundance of precursors (VOCs:NOx). The ratio of RRI_VOC to RRI_NOx showed negative values in majority of the cities; therefore, collaborative VOCs emission reduction is necessary to suppress the deterioration of O3 volume fraction. The absolute value of this ratio was much lower in cities with high industrialization and urbanization than in ordinary small and medium-sized cities, implying that the demand for collaborative VOCs emission reduction in these cities will be higher. However, even under 50% reduction of precursors, the improvement in O3 volume fraction was limited in regional cities, and the combined prevention in neighboring cities remains important.

Free amino acids, carbon and nitrogen isotopic compositions responses to cadmium stress in two castor (Ricinus communis L.) species.

Cadmium (Cd) toxicity induce various disturbances in metabolic processes and impair plant establishment. The composition of carbon and nitrogen stable isotopes (δ13C and δ15N) and free amino acids (FAAs) can reflect the response of plants to environmental stress. In the present study, a solution culture experiment was carried out, and the secretion characteristics of FAAs as well as δ13C and δ15N were evaluated as indicative of the functional performance of two castor species (Zibo-3 and Zibo-9) under various Cd concentrations stress (0, 1, 2, and 5 mg L-1). The results indicated that: 1) The treatment of the plants with 5 mg L-1 of a Cd solution resulted in a significant decline of biomasses by 22.4% and 11.6% in Zibo-3 and Zibo-9, respectively, relative to controls; additionally, the accumulation levels for Cd in Zibo-9 were higher than those in Zibo-3, thus Zibo-9 showed higher tolerance and enrichment ability to Cd. 2) The exposure of castor to Cd treatments results in significant modifications in individual FAAs, suggesting a differential sensitivity of each biosynthetic pathway to this stress; however, a positive correlation was found between the accumulation of total FAAs and Cd treatment dosages; higher proportion of asparagine and glutamate in total amino acids for Zibo-9, and abundant secretion of arginine in Cd treated Zibo-9 may be associated with the higher Cd-tolerance and Cd-accumulation in Zibo-9. 3) Cd stress increased leaf δ13C and δ15N values regardless of the castor species; δ13C and δ15N could be used as monitoring tools for heavy metal stress in plants.

Rivers draining contrasting landscapes exhibit distinct potentials to emit diffusive methane (CH4).

Methane (CH4) is the second most important greenhouse gas, contributing approximately 17% of radiative forcing, and CH4 emissions from river networks due to intensified human activities have become a worldwide issue. However, there is a dearth of information on the CH4 emission potentials of different rivers, especially those draining contrasting watershed landscapes. Here, we examined the spatial variability of diffusive CH4 emissions and discerned the roles of environmental factors in influencing CH4 production in different river reaches (agricultural, urban, forested and mixed-landscape rivers) from the Chaohu Lake Basin in eastern China. According to our results, the urban rivers most frequently exhibited extremely high CH4 concentrations, with a mean concentration of 5.46 µmol L-1, equivalent to 4.1, 9.7, and 7.2 times those measured in the agricultural, forested, and mixed-landscape rivers, respectively. The availability of carbon sources and total phosphorus were commonly identified as the most important factors for CH4 production in agricultural and urban rivers. Dissolved oxygen and oxidation-reduction potential were separately discerned as important factors for the forested and mixed-landscape rivers, respectively. Monte Carlo flux estimations demonstrated that rivers draining contrasting landscapes exhibit distinct potentials to emit CH4. The urban rivers had the highest CH4 emissions, with a flux of 9.44 mmol m-2 d-1, which was 5.1-10.4 times higher than those of the other river reaches. Overall, our study highlighted that management actions should be specifically targeted at the river reaches with the highest emission potentials and should carefully consider the influences of different riverine environmental conditions as projected by their watershed landscapes.

Attenuated sensitivity of ozone to precursors in Beijing-Tianjin-Hebei region with the continuous NOx reduction within 2014-2018.

Facing the elevated surface summer O3 over North China in recent years with the continuous NOx reduction, we conducted the ozone-precursor sensitivity study in summer (July) in Beijing-Tianjin-Hebei region (BTH) under the 2018 and 2014 emissions, based on WRF-Chem model. On 2018 emission condition, 30% precursor reduction simulations presented the positive contribution of VOCs and the negative contribution of NOx to daytime O3. The occurrence probabilities of VOCs-sensitive, NOx-titration, mixed sensitive, NOx-sensitive, and non-sensitive regimes respectively reached 3-49%, 2-82%, 0-7%, 0-6% and 14-82% in the urban grids, and 2-32%,1-19%, 1-6%, 0-5% and 54-86% in the rural grids. For several widely used photochemical indicators, their values in VOCs-sensitive regime were well separated from those in NOx-sensitive regime, but the NOx-sensitive values were very similar to the non-sensitive values, which implied the inefficiency of these indicators in indicating NOx-sensitive regime. Finally, VOCs-sensitive regime was discerned based on the indicator HCHO/NO2, occupying about a third of areas in morning and dusk but shrinking to about a tenth of areas in 11:00-16:00 in BTH. And these areas apparently decreased from 2014 emission to 2018 emission. However, the rest areas of this region were under non-sensitive regime but not NOx-sensitive regime, for the noticeable O3 drop never happened in NOx reduction scenario. Meanwhile, the modeled O3/PAN in the areas under non-sensitive regime exceeded 60, which also implied the minor impact of local photochemistry on O3 there. Additionally, the responses of daytime O3 to precursor emissions in the urban grids were calculated, declining by 20.8% for NOx and 6.9% for VOCs from 2014 to 2018. Therefore, to solve the ozone pollution problem of BTH, the cross-region strategy coupled with the VOCs and NOx co-control will be essential.

Circ-SMARCA5 suppresses progression of multiple myeloma by targeting miR-767-5p.

BACKGROUND: We aimed to investigate the correlation of Circ-SMARCA5 with disease severity and prognosis in multiple myeloma (MM), and its underlying mechanisms in regulating cell proliferation and apoptosis. METHODS: Bone marrow samples from 105 MM patients and 36 healthy controls were collected for Circ-SMARCA5 expression measurement. And the correlation of Circ-SMARCA5 expression with patients' characteristics and survival was determined. In vitro, the effect of Circ-SMARCA5 on MM cell proliferation and apoptosis was evaluated by altering Circ-SMARCA5 expression through transfection. Rescue experiments and luciferase assay were further performed to explore the mechanism of Circ-SMARCA5 as well as its potential target miR-767-5p in regulating MM cell activity. RESULTS: Circ-AMARCA5 was downregulated in MM and presented a good value in distinguishing MM patients from controls and it was also negatively correlated with Beta-2-microglobulin (ß2-MG) level and International Staging System (ISS) stage. Additionally, Circ-SMARCA5 high expression was associated with higher CR as well as better PFS and OS. As for in vitro experiments, Circ-SMARCA5 expression was lower in MM cell lines compared with normal cells, and Circ-SMARCA5 overexpression inhibited cell proliferation but promoted cell apoptosis in RPMI8226 cells. Rescue experiments disclosed that the effect of Circ-SMARCA5 on cell activity was attenuated by miR-767-5p, and luciferase reporter assay revealed direct binding between Circ-SMARCA5 and miR-767-5p. CONCLUSIONS: Circ-SMARCA5 is downregulated and correlated with lower ß2-MG level and ISS stage as well as better prognosis in MM patients, and it inhibits proliferation but promotes apoptosis of MM cells via directly sponging miR-767-5p.

Mg-Ion Battery Electrode: An Organic Solid's Herringbone Structure Squeezed upon Mg-Ion Insertion.

We report that crystalline 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA), an organic solid, is highly amenable to host divalent metal ions, i.e., Mg2+ and Ca2+, in aqueous electrolytes, where the van der Waals structure is intrinsically superior in hosting charge-dense ions. We observe that the divalent nature of Mg2+ causes unique squeezing deformation of the electrode structure, where it contracts and expands in different crystallographic directions when hosting the inserted Mg-ions. This phenomenon is revealed experimentally by ex situ X-ray diffraction and transmission electron microscopy, and is investigated theoretically by first-principles calculations. Interestingly, hosting one Mg2+ ion requires the coordination from three PTCDA molecules in adjacent columns of stacked molecules, which rotates the columns, thus reducing the (011) spacing but increasing the (021) spacing. We demonstrate that a PTCDA Mg-ion electrode delivers a reversible capacity of 125 mA h g-1, which may include a minor contribution of hydronium storage, a good rate capability by retaining 75 mA h g-1 at 500 mA g-1 (or 3.7 C), and a stable cycle life. We also report Ca2+ storage in PTCDA, where a reversible capacity of over 80 mA h g-1 is delivered.

Fundamentally Addressing Bromine Storage through Reversible Solid-State Confinement in Porous Carbon Electrodes: Design of a High-Performance Dual-Redox Electrochemical Capacitor.

Research in electric double-layer capacitors (EDLCs) and rechargeable batteries is converging to target systems that have battery-level energy density and capacitor-level cycling stability and power density. This research direction has been facilitated by the use of redox-active electrolytes that add faradaic charge storage to increase energy density of the EDLCs. Aqueous redox-enhanced electrochemical capacitors (redox ECs) have, however, performed poorly due to cross-diffusion of soluble redox couples, reduced cycle life, and low operating voltages. In this manuscript, we propose that these challenges can be simultaneously met by mechanistically designing a liquid-to-solid phase transition of oxidized catholyte (or reduced anolyte) with confinement in the pores of electrodes. Here we demonstrate the realization of this approach with the use of bromide catholyte and tetrabutylammonium cation that induces reversible solid-state complexation of Br2/Br3-. This mechanism solves the inherent cross-diffusion issue of redox ECs and has the added benefit of greatly stabilizing the reactive bromine generated during charging. Based on this new mechanistic insight on the utilization of solid-state bromine storage in redox ECs, we developed a dual-redox EC consisting of a bromide catholyte and an ethyl viologen anolyte with the addition of tetrabutylammonium bromide. In comparison to aqueous and organic electric double-layer capacitors, this system enhances energy by factors of ca. 11 and 3.5, respectively, with a specific energy of ∼64 W·h/kg at 1 A/g, a maximum power density >3 kW/kg, and cycling stability over 7000 cycles.

Hydronium-Ion Batteries with Perylenetetracarboxylic Dianhydride Crystals as an Electrode.

We demonstrate for the first time that hydronium ions can be reversibly stored in an electrode of crystalline 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA). PTCDA exhibits a capacity of 85 mAh g-1 at 1 A g-1 after an initial conditioning process. Ex situ X-ray diffraction revealed reversible and significant structure dilation upon reduction of PTCDA in an acidic electrolyte, which can only be ascribed to hydronium-ion intercalation. The lattice expansion upon hydronium storage was theoretically explored by first-principles density functional theory (DFT) calculations, which confirmed the hydronium storage in PTCDA.

Economic co-production of poly(malic acid) and pullulan from Jerusalem artichoke tuber by Aureobasidium pullulans HA-4D.

BACKGROUND: poly(L-malic acid) (PMA) is a water-soluble polyester with many attractive properties in medicine and food industries, but the high cost of PMA fermentation has restricted its further application for large-scale production. To overcome this problem, PMA production from Jerusalem artichoke tubers was successfully performed. Additionally, a valuable exopolysaccharide, pullulan, was co-produced with PMA by Aureobasidum pullulans HA-4D. RESULTS: The Jerusalem artichoke medium for PMA and pullulan co-production contained only 100 g/L hydrolysate sugar, 30 g/L CaCO3 and 1 g/L NaNO3. Compared with the glucose medium, the Jerusalem artichoke medium resulted in a higher PMA concentration (114.4 g/L) and a lower pullulan concentration (14.3 g/L) in a 5 L bioreactor. Meanwhile, the activity of pyruvate carboxylase and malate dehydrogenas was significantly increased, while the activity of α-phosphoglucose mutase, UDP-glucose pyrophosphorylase and glucosyltransferase was not affected. To assay the economic-feasibility, large-scale production in a 1 t fermentor was performed, yielding 117.5 g/L PMA and 15.2 g/L pullulan. CONCLUSIONS: In this study, an economical co-production system for PMA and pullulan from Jerusalem artichoke was developed. The medium for PMA and pullulan co-production was significantly simplified when Jerusalem artichoke tubers were used. With the simplified medium, PMA production was obviously stimulated, which would be associated with the improved activity of pyruvate carboxylase and malate dehydrogenas.

Hard carbon anodes of sodium-ion batteries: undervalued rate capability.

The rate capability of hard carbon has long been underestimated in prior studies that used carbon/Na two-electrode half-cells. Through a three-electrode cell setup, we discover that it is the overpotential of the sodium counter electrode that drives the half-cells to the lower cutoff potential prematurely during hard carbon sodiation, particularly at high current rates, which prevents the hard carbon anode from being fully sodiated.

Efficient Charge Storage in Dual-Redox Electrochemical Capacitors through Reversible Counterion-Induced Solid Complexation.

The performance of redox-enhanced electrochemical capacitors (redox ECs) is substantially improved when oxidized catholyte (bromide) and reduced anolyte (viologen) are retained within the porous electrodes through reversible counterion-induced solid complexation. Investigation of the mechanism illustrates design principles and identifies pentyl viologen/bromide (PV/Br) as a new high-performance electrolyte. The symmetric PV/Br redox EC produces a specific energy of 48.5 W·h/kgdry at 0.5 A/gdry (0.44 kW/kgdry) with 99.7% Coulombic efficiency, maintains stability over 10 000 cycles, and functions identically when operated with reversed polarity.

High Energy Density Aqueous Electrochemical Capacitors with a KI-KOH Electrolyte.

We report a new electrochemical capacitor with an aqueous KI-KOH electrolyte that exhibits a higher specific energy and power than the state-of-the-art nonaqueous electrochemical capacitors. In addition to electrical double layer capacitance, redox reactions in this device contribute to charge storage at both positive and negative electrodes via a catholyte of IOx-/I- couple and a redox couple of H2O/Had, respectively. Here, we, for the first time, report utilizing IOx-/I- redox couple for the positive electrode, which pins the positive electrode potential to be 0.4-0.5 V vs Ag/AgCl. With the positive electrode potential pinned, we can polarize the cell to 1.6 V without breaking down the aqueous electrolyte so that the negative electrode potential could reach -1.1 V vs Ag/AgCl in the basic electrolyte, greatly enhancing energy storage. Both mass spectroscopy and Raman spectrometry confirm the formation of IO3- ions (+5) from I- (-1) after charging. Based on the total mass of electrodes and electrolyte in a practically relevant cell configuration, the device exhibits a maximum specific energy of 7.1 Wh/kg, operates between -20 and 50 °C, provides a maximum specific power of 6222 W/kg, and has a stable cycling life with 93% retention of the peak specific energy after 14,000 cycles.

Design of aqueous redox-enhanced electrochemical capacitors with high specific energies and slow self-discharge.

Electrochemical double-layer capacitors exhibit high power and long cycle life but have low specific energy compared with batteries, limiting applications. Redox-enhanced capacitors increase specific energy by using redox-active electrolytes that are oxidized at the positive electrode and reduced at the negative electrode during charging. Here we report characteristics of several redox electrolytes to illustrate operational/self-discharge mechanisms and the design rules for high performance. We discover a methyl viologen (MV)/bromide electrolyte that delivers a high specific energy of ∼14 Wh kg(-1) based on the mass of electrodes and electrolyte, without the use of an ion-selective membrane separator. Substituting heptyl viologen for MV increases stability, with no degradation over 20,000 cycles. Self-discharge is low, due to adsorption of the redox couples in the charged state to the activated carbon, and comparable to cells with inert electrolyte. An electrochemical model reproduces experiments and predicts that 30-50 Wh kg(-1) is possible with optimization.

Superior cathode of sodium-ion batteries: orthorhombic V2O5 nanoparticles generated in nanoporous carbon by ambient hydrolysis deposition.

For the first time, we demonstrate that orthorhombic V2O5 can exhibit superior electrochemical performance in sodium ion batteries when uniformly coated inside nanoporous carbon. The encapsulated V2O5 shows a specific capacity as high as 276 mAh/g, while the whole nanocomposite exhibits a capacity of 170 mAh/g. The V2O5/C composite was fabricated by a novel ambient hydrolysis deposition that features sequential water vapor adsorption in nanoporous carbon, followed by a hydrolysis reaction, exclusively inside the nanopores. The unique structure of the nanocomposite significantly enhances the capacity as well as the rate performance of orthorhombic V2O5 where the composite retains a capacity of over 90 mAh/g at a current rate of 640 mA/g. Furthermore, by calculating, we also revealed that a large portion of the sodium-ion storage, particularly at high current rates, is due to the V2O5 pseudocapacitance.

Multiple ambient hydrolysis deposition of tin oxide into nanoporous carbon to give a stable anode for lithium-ion batteries.

A novel ambient hydrolysis deposition (AHD) methodology that employs sequential water adsorption followed by a hydrolysis reaction to infiltrate SnO2 nanoparticles into the nanopores of mesoporous carbon in a conformal and controllable manner is introduced. The empty space in the SnO2/C composites can be adjusted by varying the number of AHD cycles. An SnO2/C composite with an intermediate SnO2 loading exhibited an initial specific delithiation capacity of 1054 mAh g(-1) as an anode for Li-ion batteries. The capacity contribution from SnO2 in the composite electrode approaches the theoretical capacity of SnO2 (1494 mAh g(-1)) if both Sn alloying and SnO2 conversion reactions are considered to be reversible. The composite shows a specific capacity of 573 mAh g(-1) after 300 cycles, that is, one of the most stable cycling performances for SnO2/mesoporous carbon composites. The results demonstrated the importance of well-tuned empty space in nanostructured composites to accommodate expansion of the electrode active mass during alloying/dealloying and conversion reactions.

[Effects of down-regulated TRAF6 gene expression on the proliferation and apoptosis in multiple myeloma cells].

OBJECTIVE: To investigate the down-regulated TRAF6 gene expression and its effects on proliferation and apoptosis in multiple myeloma (MM) cells. METHODS: Detection of TRAF6 expression were conducted by RT-PCR and Western blot in MM cell lines of KM3, U266, RPMI8226 and primary cells from patients. RPMI8226 cell lines were transfected with siRNA of TRAF6. The efficiency of transfection was identified by using of fluorescence microscope, RT-PCR, and Western blot. The levels of proliferation were analyzed by CCK-8 method under the different concentrations of siRNA. Apoptosis rate were detected with Hoechst33258/PI double staining by flow cytometry. Apoptosis related proteins Bcl-2, BAX, and NF-κB signal pathway were observed before and after siRNA transfection by Western blot. RESULTS: The levels of TRAF6 mRNA and protein in MM cell lines, especially in primary myeloma cells, were significantly higher than those in controls. After transfected with 50 nmol/L siRNA in RPMI8226 cells, the relative level of TRAF6 mRNA (0.49±0.24) was significantly lower than that in non-transfected group (1.87±0.23) and idling group (1.74±0.35). The proliferation rate of siRNA transfected cells decreased with dose dependence (P<0.01). The apoptosis rates increased from 11.20% (before transfection) to 51.82% (after transfection), accompanied by down-regulated Bcl-2 protein, NF-κB signal pathway (p-p65 and p52), and up-regulated BAX protein. CONCLUSION: TRAF6 expression was high in myeloma cells. TRAF6 siRNA could inhibit proliferation of myeloma cells and induce apoptosis mediated by NF-κB classical and alternative pathway in myeloma cells.

Production of graphene by reduction using a magnesiothermic reaction.

We have, for the first time, employed a magnesiothermic reaction to convert microwave-irradiated graphite oxide to pure graphene. The magnesiothermic reaction increases the carbon to oxygen atomic ratio from 22.2 to 165.7 and maintains a high surface area. The new strategy demonstrates an efficient method for obtaining highly pure graphene materials.

Efficient fabrication of nanoporous si and Si/Ge enabled by a heat scavenger in magnesiothermic reactions.

Magnesiothermic reduction can directly convert SiO2 into Si nanostructures. Despite intense efforts, efficient fabrication of highly nanoporous silicon by Mg still remains a significant challenge due to the exothermic reaction nature. By employing table salt (NaCl) as a heat scavenger for the magnesiothermic reduction, we demonstrate an effective route to convert diatom (SiO2) and SiO2/GeO2 into nanoporous Si and Si/Ge composite, respectively. Fusion of NaCl during the reaction consumes a large amount of heat that otherwise collapses the nano-porosity of products and agglomerates silicon domains into large crystals. Our methodology is potentially competitive for a practical production of nanoporous Si-based materials.