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The structure of a new crystal form of methanol dehydrogenase derived from Methylophilus W3A1 was studied using data recorded at a synchrotron. At 1.9 angstrom resolution, details of the configuration of the redox factor pyrroloquinoline quinone (PQQ) were observed. C4, one of the oxygen-bearing atoms, is in a planar configuration while C5, which bears the other quinone oxygen, is tetrahedral. These suggest that PQQ is in the semiquinone redox state.

Tetrabromobisphenol A (TBBPA) and hexabromocyclododecane diastereoisomers (αβ, and γ-HBCD) were determined in 24 pooled human milk samples and 48 Chinese total diet study (TDS) samples collected in 2007. On the basis of ultra performance liquid chromatography-mass spectrometry (UPLC- MS/MS) analysis, levels of TBBPA ranged from

Neonicotinoid insecticides (NNIs) are extensively utilized globally because of their efficient and broad-spectrum properties. However, their residues are also extensively distributed in the environment. Herein, MIL-101-SO 3 Na with abundant -NH- and sulfonate groups was synthesized via chloromethylation and nucleophilic substitution postmodification strategies and used to extract NNIs via solid-phase extraction. MIL-101-SO 3 Na was enhanced by introducing C-H···N hydrogen bonds to strengthen interaction forces and -SO 3 Na groups to adjust surface charge and enhance electrostatic attraction. This modification and the substantial specific surface area (998 m 2 ·g -1 ) of the metal-organic framework markedly enhanced the enrichment efficiency of MIL-101. The proposed method based on MIL-101-SO 3 Na exhibited a minimal detection threshold (0.04-0.87 ng·L -1 ), an extensive linear spectrum (1-2000 ng·L -1 ), and notable accuracy (a variation of 3.02-11.8%) in water and drink samples. NNI concentrations between 0.25 and 24.2 ng·L -1 in fruit juice and tea samples were accurately identified using the proposed method, demonstrating its feasibility in practical applications. The postmodification of MIL-101-SO 3 Na is an exceptional and promising approach for the sensitive detection of ultratrace NNI levels in complex matrices.

Challenges remain to show good capacitive performance while achieving high loadings of active materials for supercapacitors. Trying to realize this version, a nickel-protecting carbon fiber paper@Co-doped NiS x (Ni-CP@Co-NiS x ) electrode with high specific gravimetric, areal, and volumetric capacitance is reported in this work. This free-standing electrode is prepared by an electroplating-hydrothermal-electroplating (EHE) three-step method to achieve a high loading of almost 26.7 mg cm -2 . The cobalt-doping and nickel-protection strategies effectively decrease the impedance and inhibit the active material dropping from the electrode resulting from the expansion stress, which endows the Ni-CP@Co-NiS x electrode with a high rate and good cycling performance, especially with an ultrahigh specific areal/volumetric/gravimetric capacitance of 53.3 F cm -2 /2807 F cm -3 /1997 F g -1 at 5 mA cm -2 , respectively. Employing activated carbon functionalized with riboflavin (AC/VB2) as a negative electrode, the asymmetric supercapacitor device delivers a very high energy density of up to 60.4 W h kg -1 . This work demonstrates that electrodes with a high loading density and excellent performance can be obtained by the combination of the EHE method to adjust the internal conductivity and external structural stability.

Spatial hindrance of lithium polysulfide (LiPS) diffusion by inserting a barrier interlayer has been deemed as an effective strategy to restrict the shuttle effect in lithium-sulfur batteries (LSBs). However, the extra interlayer without reversible capacity production inevitably reduces the actual energy density of the battery. Herein, a freestanding α-MoO 3 nanobelt interlayer with the decoration of TiN nanoparticles and carbon nanotubes (denoted as MCT) is established. To investigate the capacity compensation effect of the MCT during cell operations, X-ray absorption near-edge spectrometry is conducted. It is revealed that MoO 3 can sustain a reversible Li intercalation/deintercalation in a voltage range of 1.8-2.8 V, providing 180 mAh g -1 of extra capacity for compensating sulfur cathode. In addition, the adsorption of the lithiated α-MoO 3 toward LiPSs is further evaluated. By matching a high-loading sulfur cathode (3.0 mg cm -2 ), a superior capacity of 713.3 mAh g -1 can be retained after 100 cycles under the MCT assistance.

The development of potassium-ion batteries (PIBs) is challenged by the shortage of stable cathode materials capable of reversibly hosting the large-sized K + (1.38 Å), which is prone to cause severe structural degradation and complex phase evolution during the potassiation/depotassiation process. Here, we identified that anionic doping of the layered oxides for PIBs is effective to combat their capacity fading at high voltage (>4.0 V). Taking P2-type K 2/3 Mn 7/9 Ni 1/9 Ti 1/9 O 17/9 F 1/9 (KMNTOF) as an example, we showed that the partial substitution of O 2- by F - enlarged the interlayer distance of the K 2/3 Mn 7/9 Ni 1/9 Ti 1/9 O 2 (KMNTO), which becomes more favorable for fast K + transition without violent structural destruction. Meanwhile, based on the experimental data and theoretical results, we identified that the introduction of F - anions effectively increased the redox-active Mn cationic concentration by lowering the average valence of the Mn element, accordingly providing more reversible capacity derived from the Mn 3+/4+ redox couple, rather than oxygen redox. This anionic doping strategy enables the KMNTOF cathode to deliver a high reversible capacity of 132.5 mAh g -1 with 0.53 K + reversible (de)intercalation in the structure. We expect that the discovery provides new insights into structural engineering for pursuing stable cathodes to facilitate the future applications of high-performance PIBs.

Lithium-sulfur (Li-S) batteries have been regarded as a promising candidate of secondary batteries to satisfy the enormous demand for electric vehicles and energy storage applications. However, Li-S batteries still suffer from severe capacity fading due to the shuttle effect of lithium polysulfides. Here, we develop a freestanding double-layer MoO 3 /carbon nanotube@S (FMC@S) membrane by hydrothermal and suction filtration strategy, without polymer binder and current collector substrate. FMC@S contains a polysulfide blocking layer and an active material layer. Except for S content, the two layers have the same components and are integrated together, so there is no distinct interface between the two layers, which can facilitate ion and electron transport. As a result, the FMC@S cathode delivers promising capacity retention and rate capability. The hierarchical integrated design provides a new strategy to develop high-performance flexible cathodes for Li-S batteries.

Solid materials with special atomic and electronic structures are deemed desirable platforms for establishing clear relationships between surface/interface structure characteristics and electrochemical activity. In this work, nickel boride (Ni x B) and nickel boride/graphene (Ni x B/G) are chosen as positive materials of supercapacitors. The Ni x B/G displays higher specific capacitance (1822 F g -1 ) than that of Ni x B (1334 F g -1 ) at 1 A g -1 , and it still maintains 1179 F g -1 at 20 A g -1 , suggesting the high rate performance. The asymmetric supercapacitor device (Ni x B/G//activated carbon) also delivered a very high energy density of 50.4 Wh kg -1 , and the excellent electrochemical performance is ascribed to the synergistic effect of Ni x B, Ni(BO 2 ) 2 , and graphene that fully enhances the diffusion of OH - and the electron transport. During the cycles, the prepared ultrafine Ni x B nanoparticles will be gradually in situ converted into β-Ni(OH) 2 which has a smaller particle size than that prepared by other methods. This will enhance the utilization of Ni(OH) 2 and decrease the ion diffusion distance. The electron deficient state of B in Ni(BO 2 ) 2 amorphous shell will make it easy to accept extra electrons, enhancing the adsorption of OH - at the shell surface. Moreover, Ni(BO 2 ) 2 makes strong adhesion between Ni x B (or β-Ni(OH) 2 ) and graphene and protects the core structure in a stable state, extending the cycle life. The above properties of Ni x B/G endow the electrode good capacitive performance.

LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA) has been proven to be a good cathode material for lithium-ion batteries (LIBs), especially in electric vehicle applications. However, further elevating energy density of NCA is very challenging. Increasing the charging voltage of NCA is an effective method, but its structural instability remains a problem. In this work, we revealed that titanium substitution could improve cycle stability of NCA under high cutoff voltage significantly. Titanium ions with a relatively larger ion radius could modify the oxygen lattice and change the local coordination environment of NCA, leading to decreased cation migration, better kinetic and thermodynamic properties, and improved structural stability. As a result, the Ti-substituted NCA cathode exhibits impressive reversible capacity (198 mA h g -1 at 0.1C) with considerable cycle stability under a cutoff voltage up to 4.7 V. It is also revealed that Ti could suppress oxygen release in the high-voltage region, benefitting cycle and thermal stabilities. This work provides valuable insight into the design of high-voltage layered cathode materials for high-energy-density LIBs.

Pseudocapacitance plays an important role in high-power lithium-ion batteries (LIBs). However, it is still lack of effective methods to tailor the pseudocapacitance contribution in electrode materials for LIBs. Herein, pseudocapacitance tuned by the strength of C-S bonding has been rendered in WS 2 nanorods anchored on the N,S codoped three-dimensional graphene hybrid (WS 2 @N,S-3DG) for the first time. The pseudocapacitive contributions in the charge storage can be enhanced effectively with the increased strength of C-S bonding. As expected, the enhanced extrinsic pseudocapacitance makes WS 2 @N,S-3DG a fascinating electrode material for high-power LIBs, with a high reversible capacity of 509 mA h g -1 over 500 cycles at a current density as high as 2 A g -1 . These encouraging results of pseudocapacitance tailored by chemical bonding provide new opportunities for designing advanced electrode materials.

As a novel class of soft matter, two-dimensional (2D) atomic nanosheet-like crystals have attracted much attention for energy storage devices due to the fact that nearly all of the atoms can be exposed to the electrolyte and involved in redox reactions. Herein, atomically thin γ-FeOOH nanosheets with a thickness of ∼1.5 nm are synthesized in a high yield, and the band and electronic structures of the γ-FeOOH nanosheet are revealed using density-functional theory calculations for the first time. The rationally designed γ-FeOOH@rGO composites with a heterostacking structure are used as an anode material for lithium-ion batteries (LIBs). A high reversible capacity over 850 mAh g(-1) after 100 cycles at 200 mA g(-1) is obtained with excellent rate capability. The remarkable performance is attributed to the ultrathin nature of γ-FeOOH nanosheets and 2D heterostacking structure, which provide the minimized Li(+) diffusion length and buffer zone for volume change. Further investigation on the Li storage electrochemical mechanism of γ-FeOOH@rGO indicates that the charge-discharge processes include both conversion reaction and capacitive behavior. This synergistic effect of conversion reaction and capacitive behavior originating from 2D heterostacking structure casts new light on the development of high-energy anode materials.

A novel small-molecule compound of lithium iodine and 3-hydroxypropionitrile (HPN) has been successfully synthesized. Our combined experimental and theoretical studies indicated that LiIHPN is a Li-ion conductor, which is utterly different from the I(-)-anion conductor of LiI(HPN)2 reported previously. Solid-state lithium-air batteries based on LiIHPN as the electrolyte exhibit a reversible discharge capacity of more than 2100 mAh g(-1) with a cyclic performance over 10 cycles. Our findings provide a new way to design solid-state electrolytes toward high-performance lithium-air batteries.

A rapid, sensitive, reproducible, and inexpensive method of high-performance liquid chromatography with fluorescence detection after an anion-exchange solid-phase extraction cleanup step for the analysis of ochratoxin A (OTA) in Chinese wine was developed. The average recovery rate and the average RSD of recovery were 97.47% and about 4%. The relative standard deviations of both the interday and intraday precision were 6.7 and 12.6%, respectively. The limits of detection and quantitation were determined to be 0.01 and 0.03 μg/L, respectively. A total of 223 samples from the major wine-producing areas of China were analyzed for OTA. OTA was detected at levels of 0.01-0.98 μg/L. The mean was 0.15 μg/L. Then, participants as representative inhabitants were invited to answer the designed questionnaire about the quantity and frequency of wine consumption. All data were simulated by the point evaluation for the risk assessment of OTA contamination from wine. Those results indicated that daily intake (DI) of OTA for the average adult consumer varies between 0.86 and 1.08 ng/kg bw per week, which was lower than all the reference standards. However, the DI value (4.38-5.54 ng/kg bw per week) in the high percentile (97.5) was slightly above 5% PTWI (100 ng kg(-1) week(-1)) of the JECFA. In conclusion, OTA exposure from Chinese wine has no risk of harm. This research will provide the scientific basis for determining the maximum limit of OTA content in Chinese wine.

One hundred and one tea samples including green tea, dark tea, scented tea, black tea, and oolong tea were screened and confirmed for the contamination of 31 organochlorine pesticides (OCPs) and 19 pyrethroids (PYs) by gas chromatography-negative chemical ionization-mass spectrometry (GC-NCI-MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS). 50 pesticides, 3 deuterium-labeled PYs, and 24 (13)C-labeled OCPs were separated well with the limits of detection (LODs) ranging from 0.02 to 4.5 μg/kg for GC-NCI-MS, and the positive samples were verified by GC-MS/MS with LODs of 0.1-5.0 μg/kg. High detection rates for some PYs, such as 63.4% for bifenthrin (not detected (ND)-3.848 mg/kg), 55.4% for λ-cyhalothrin (ND-3.244 mg/kg), 46.5% for cypermethrin (ND-0.499 mg/kg), and 24.8% for fenvalerate (ND-0.217 mg/kg), were found in the 101 tea samples. Endosulfan, DDTs, HCHs, and heptachlor, the persistent OCPs, were frequently detected with rates of 63.4% (ND-1.802 mg/kg), 56.4% (ND-0.411 mg/kg), 24.8% (ND-0.377 mg/kg), and 15.8% (ND-0.100 mg/kg), respectively.

Tetrabromobisphenol A(TBBPA) and hexabromocyclododecane diastereoisomers (alpha, beta, and gamma-HBCD) were determined in 24 pooled human milk samples and 48 Chinese total diet study (TDS) samples collected in 2007. On the basis of ultra performance liquid chromatography-mass spectrometry (UPLC-MS/MS) analysis, levels of TBBPA ranged from < LOD to 5124 pg/g lipid weight (lw) in human milk and from < LOD to 2044 pg/g lw in TDS samples. The alpha-HBCD diastereoisomer, which ranged from < LOD to 2776 pg/g lw in human milk and from < LOD to 2224 pg/g lw in TDS samples, was generally the most abundant isomer comparing with beta- and gamma-HBCD. The average estimated daily intake (EDI) of TBBPA via human milk for nursing infants with a range 320-37240 pg/kg bodyweight (bw)/day was 5094 pg/kg bw/day, while that of sigmaHBCD was 5837 pg/kg bw/day with a range 670-17320 pg/kg bw/day. The medium bound (< LOD = 1/2LOD) EDI(TBBPA) for a "reference" man via animal origin foods was 256 pg/kg bw/day and EDI(sigmaHBCD) was 432 pg/kg bw/day. Meat and meat products were the main source in the total dietary intake of TBBPA and sigmaHBCD. Our research on the estimated daily intake of TBBPA and sigmaHBCD by the Chinese population indicated large variations in TBBPA and sigmaHBCD levels between provinces. Overall, our data indicate the Chinese EDI was lowerthan the EDI from similar studies in Europe.

To investigate the occupational exposure levels to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs), indoor dust (n = 3) in workshops and hair samples from male workers (n = 64) were collected at two electrical and electronic equipmentwaste (E-waste) dismantling factories located in the LQ area in east China in July 11--13, 2006. Pre- and postworkshift urines (64 of each) were also collected from the workers to study oxidative damage to DNA using 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a biomarker. The concentrations of PCDD/Fs, PCDD/F-WHO-TEQs, PBDEs, PCBs and PCB-WHO-TEQs were (50.0 +/- 8.1) x 10(3), 724.1 +/- 249.6, (27.5 +/- 5.8) x 10(6), (1.6 +/- 0.4) x 10(9), (26.2 +/- 3.0) x 10(3) pg/g dry weight (dw) in dust, and (2.6 +/- 0.6) x 10(3),42.4 +/- 9.3, (870.8 +/- 205.4) x 10(3), (1.6 +/- 0.2) x 10(6), 41.5 +/- 5.5 pg/g dw in hair, respectively. The homologue and congener profiles in the samples demonstrated that high concentrations of PCDD/Fs, PBDEs, and PCBs were originated from open burning of E-waste. The 8-OHdG levels were detected at 6.40 +/- 1.64 micromol/mol creatinine in preworkshift urines. However, the levels significantly increased to 24.55 +/- 5.96 micromol/mol creatinine in postworkshift urines (p < 0.05). Then, it is concluded that there is a high cancer risk originated from oxidative stress indicated by the elevated 8-OHdG levels in the E-waste dismantling workers exposed to high concentrations of PCDD/Fs, PBDEs, and PCBs.