All-solid-state batteries are appealing electrochemical energy storage devices because of their high energy content and safety. However, their practical development is hindered by inadequate cycling ...performances due to poor reaction reversibility, electrolyte thickening and electrode passivation. Here, to circumvent these issues, we propose a fluorination strategy for the positive electrode and solid polymeric electrolyte. We develop thin laminated all-solid-state Li||FeF
lab-scale cells capable of delivering an initial specific discharge capacity of about 600 mAh/g at 700 mA/g and a final capacity of about 200 mAh/g after 900 cycles at 60 °C. We demonstrate that the polymer electrolyte containing AlF
particles enables a Li-ion transference number of 0.67 at 60 °C. The fluorinated polymeric solid electrolyte favours the formation of ionically conductive components in the Li metal electrode's solid electrolyte interphase, also hindering dendritic growth. Furthermore, the F-rich solid electrolyte facilitates the Li-ion storage reversibility of the FeF
-based positive electrode and decreases the interfacial resistances and polarizations at both electrodes.
Conventional TiO2-based photocatalysts oxidize NO x to nitrate species, which do not spontaneously desorb and therefore deactivate the catalyst. We show that the selectivity of this reaction can be ...changed by creating a large concentration of oxygen vacancies in TiO2 nanoparticles through thermal reduction in a reducing atmosphere. This results in the photoreduction of nitric oxide (NO) to N2 and O2, species which spontaneously desorb at room temperature. The activity of the photoreduction reaction can be greatly enhanced by doping the TiO2 nanoparticles with Fe3+, an acceptor-type dopant that stabilizes the oxygen vacancies. Moreover, the photoinduced reduction of Fe3+ to Fe2+ provides a recombination pathway that almost completely suppresses the formation of NO2 and thus enhances the selectivity of the reaction for N2 formation. Gas chromatography confirms that N2 and O2 are formed in a stoichiometric ratio, and the activity for NO decomposition is found to be limited by the concentration of oxygen vacancies. A series of internally consistent reaction equations are proposed that describe all experimentally observed features of the photocatalytic process. The observed influence of oxygen vacancies on the activity and selectivity of photoinduced reactions may lead to new routes toward the design of highly selective photocatalysts.
The incorporation of Fe as a dopant in anatase TiO2 nanoparticles has been systematically investigated with the aim of changing the coordination geometry of Ti via the formation of oxygen vacancies. ...Although Fe3+ ions are present in the solution during growth of the nanoparticles, a high-temperature heat treatment is found to be necessary to incorporate Fe3+ as a substituent for Ti4+ in the bulk of the TiO2 nanoparticles. The Fe3+ acceptors are found to be charge-compensated by oxygen vacancies, up to dopant concentrations as high as 10%. The surprisingly high solubility of Fe is attributed to the very similar radii of Ti4+ and Fe3+ and to the energetically favorable Coulomb attraction between the negatively charged Fe acceptor and the positively charged oxygen vacancies. A combined EXAFS/XANES study reveals that part of the Ti4+ ions changes their coordination number from 6 to 4 at high oxygen vacancy concentrations. The deliberate use of oxygen vacancies to modify the coordination geometry of metal ions represents a new strategy that offers exciting possibilities to tune the selectivity of photocatalytically active metal oxide nanoparticles.
Spoilage bacteria seriously influence meat quality. In this study, the bacterial community, sensory scores, pH, and total volatile basic nitrogen (TVB-N) in refrigerated (4 °C) pork, the most ...commonly consumed meat in China, were investigated. In a high-throughput sequencing analysis of the V3–V4 region of the 16S rDNA gene, 259 bacterial genera were belonging to 21 phyla were identified. With the passage of time, the bacterial community diversity decreased. After 5 days, Pseudomonas, Acinetobacter and Photobacterium were dominant in refrigerated pork, especially Photobacterium, which rarely associated with meat spoilage. Our results suggest that these taxa contribute to refrigerated pork spoilage. During storage, pH and TVB-N showed similar trends. Additionally, total viable counts (TVC) increased steadily and sensory score decreased. On day 5, TVC, pH, TVB-N and sensory scores changed dramatically, and sensory scores indicating that the shelf life of refrigerated pork was less than 5 days. The predicted metabolic pathways, based o the data of 16S rDNA, indicated an abundant carbohydrate metabolism and amino metabolism in refrigerated pork. This study provides insight into the determinants of shelf life. Furthermore, it provides insight into the process involved in refrigerated pork spoilage.
•The microbial community dynamics of refrigerated pork during storage was evaluated.•Pseudomonas, Acinetobacter, and Photobacterium dominated in refrigerated pork.•Sensory and quality characteristics suggested the shelf life less than 5 days.•Abundant carbohydrate metabolism and amino metabolism in refrigerated pork.
Magnesium metal batteries (MMBs) have obtained the reputation owing to the high volumetric capacity, low reduction potential, and dendrite‐free deposition behavior of the Mg metal anode. However, the ...bivalent nature of the Mg2+ causes its strong coulombic interaction with the cathode host, which limits the reaction kinetics and reversibility of MMBs, especially based on oxide cathodes. Herein, a synergetic modulation of host pillaring and electrolyte formulation is proposed to activate the layered V2O5 cathode with expanded interlayers via sequential intercalations of poly(3,4‐ethylenedioxythiophene) (PEDOT) and cetyltrimethylammonium bromide (CTAB). The preservation of bundled nanowire texture, copillaring behavior of PEDOT and CTA+, dual‐insertion mode of Mg2+ and MgCl+ at cathode side enable the better charge transfers in both the bulk and interface paths as well as the interaction mitigation effect between Mg‐species cations and host lattices. The introduction of CTA+ as electrolyte additive can also lower the interface resistance and smoothen the Mg anode morphology. These modifications endow the full cells coupled with metallic Mg anode with the maximized reversible capacity (288.7 mAh g‐1) and superior cyclability (over 500 cycles at 500 mA g‐1), superior to most already reported Mg‐ion shuttle batteries even based on passivation‐resistant non‐Mg anodes or operated at higher temperatures.
A synergetic modulation of host pillaring and electrolyte formulation is proposed to activate the layered V2O5 cathode with expanded interlayers via sequential intercalations of poly(3,4‐ethylenedioxythiophene) and cetyltrimethylammonium bromide (CTAB). The introduction of CTA+ additive lowers the interface resistance and smoothens the Mg anode morphology. These modifications endow the Mg metal batteries with maximized reversible capacity and superior cyclability.
The goal of this study was to identify Cd-resistant bacterial strains with endurance capacity and to evaluate their ability to remove cadmium ions from cadmium-polluted water. The Bacillus cereusS5 ...strain identified in this study had the closest genetic relationship with B. cereus sp. Cp1 and performed well in the removal of Cd2+ions from solution. The results showed that both the live and dead biomasses of the Cd2+-tolerant B. cereus S5 strain could absorb Cd2+ ions in solution but that the live biomass of the B. cereus S5 strain outperformed the dead biomass at lower Cd2+concentrations. An analysis of the cadmium tolerance genes of B. cereus S5 identified ATPase genes that were associated with cadmium tolerance and involved in the ATP pumping mechanism. The FTIR spectra revealed the presence of amino, carboxyl and hydroxyl groups on the pristine biomass and indicated that the cadmium ion removal ability was related to the structure of the strain. The maximum absorption capacity of the B. cereus S5 strain in viable spore biomass was 70.16 mg/g (dry weight) based on a pseudo-second-order kinetic model fit to the experimental data. The Langmuir and Langmuir-Freundlich isotherm adsorption models fit the cadmium ion adsorption data well, and the kinetic curves indicated that the adsorption rate was second-order. For Cd2+ concentrations (mg/L) of 1-109 mg/L, good removal efficiency (>80%) was achieved using approximately 3.48-10.3 g/L of active spore biomass of the B. cereus S5 strain. A cadmium-tolerant bacteria-activated carbon-immobilized column could be used for a longer duration and exhibited greater treatment efficacy than the control column in the treatment of cadmium-polluted water. In addition, a toxicity assessment using mice demonstrated that the biomass of the B. cereus S5 strain and its fermentation products were non-toxic. Thus, the isolated B. cereus S5 strain can be considered an alternative biological adsorbent for use in emergency responses to severe cadmium pollution and in the routine treatment of trace cadmium pollution.
Gut microbiota influences the central nervous system disorders such as Alzheimer's disease (AD). The prebiotics and probiotics can improve the host cognition. A previous study demonstrated that ...fructooligosaccharides from
(OMO) exert effective memory improvements in AD-like animals, thereby considered as potential prebiotics; however, the underlying mechanism still remains enigma. Thus, the present study investigated whether OMO is effective in alleviating AD by targeting the microbiota-gut-brain axis. OMO was administered in rats with AD-like symptoms (D-galactose- and Aβ
-induced deficient rats). Significant and systematic deterioration in AD-like animals were identified, including learning and memory abilities, histological changes, production of cytokines, and microbial community shifts. Behavioral experiments demonstrated that OMO administration can ameliorate the learning and memory abilities in both AD-like animals significantly. AD parameters showed that OMO administration cannot only improve oxidative stress and inflammation disorder, but also regulate the synthesis and secretion of neurotransmitter. Histological changes indicated that OMO administration ameliorates the swelling of brain tissues, neuronal apoptosis, and down-regulation of the expression of AD intracellular markers (Tau and Aβ
). 16S rRNA sequencing of gut microbiota indicated that OMO administration maintains the diversity and stability of the microbial community. In addition, OMO regulated the composition and metabolism of gut microbiota in inflammatory bowel disease (IBD) mice model treated by overdosed antibiotics and thus showed the prebiotic potential. Moreover, gut microbiota plays a major role in neurodevelopment, leading to alterations in gene expression in critical brain and intestinal regions, thereby resulting in perturbation to the programming of normal cognitive behaviors. Taken together, our findings suggest that the therapeutic effect of the traditional medicine,
, on various neurological diseases such as AD, is at least partially contributed by its naturally occurring chemical constituent, OMO, via modulating the interaction between gut ecology and brain physiology.
This study was to estimate the prevalence and characteristics of
from 1,850 retail meat and meat products in China during July 2011 to June 2016. The samples were collected covering most provincial ...capitals in China, including 604 raw meat, 601 quick-frozen meat, and 645 ready-to-eat meat. Using the qualitative and quantitative methods, all 39 cities had
-positive samples, and
was detected in 35.0% (647/1,850) of the samples. The levels of
in retail meat showed that the MPN value of the majority of the positive samples ranged from 0.3 to 100 MPN/g. Twenty-four antibiotics were used to test all 868
isolates for antibiotic susceptibility. Only 11 isolates (1.26%) were susceptible to all antibiotics, whereas most isolates (821/868, 94.6%) showed resistance or intermediary resistance to more than three or more antibiotics. Of these strains, 104 (12.0%) were resistant to more than 10 antibiotics. However, the most frequent resistance was observed to ampicillin (85.4%), followed by penicillin (84.6%), erythromycin (52.7%), tetracycline (49.3%), kanamycin (45.3%), telithromycin (30.1%), clindamycin (29.6%), streptomycin (21.1%), norfloxacin (20.4%), gentamicin (19.4%), fusidic acid (18.4%), ciprofloxacin (16.9%), chloramphenicol (13.1%), amoxycillin/clavulanic acid (11.0%), and others (<10%). 7.4% of isolates (62/868) were confirmed as methicillin-resistance
(MRSA). By molecular typing analysis, there were 164
types and 111 STs were identified, including 15 novel
types and 65 newly STs by multilocus sequence typing (MLST) and
typing. Despite the wide genetic diversity observed among the 868 isolates, a great proportion of the population belonged to finite number of major clones: ST1-t127 (93/868, 10.7%) and ST7-t091 (92/868, 10.6%), ST5-t002 (42/868, 4.8%), ST398-t034 (40/868, 4.6%), ST188-t034 (38/868, 4.4%), ST59-t437 (30/868, 3.5%), ST6-t701 (29/868, 3.3%), and ST9-t899 (27/868, 3.1%) in China. This study reflects
was readily detected in Chinese retail meat and meat products but the level were not very excessive. In this study, the high antibiotic resistance is alarming and raising public health concern. In additions, most of molecular types of isolates have been linked to human infections around the world, indicating that these types of
in China have a theoretical pathogenic potential.
Vibrio parahaemolyticus is a major foodborne pathogen, particularly in Asian countries. Increased occurrence of outbreaks of V. parahaemolyticus gastroenteritis in China indicates the need to ...evaluation of the prevalence of this pathogenic species. V. parahaemolyticus distribution in shellfish from the eastern coast of China has been reported previously. However, to date, the prevalence of V. parahaemolyticus in retail aquatic products in North China has not been determined. To investigate the prevalence of V. parahaemolyticus in aquatic products in North China, 260 aquatic product samples were obtained from retail markets in 6 provinces of North China from November to December in 2012 and July to August in 2013.
V. parahaemolyticus was detected in 94 (36.2%) of the samples by the most probable number method. The density of V. parahaemolyticus ranged from 1.50 to 1100 MPN/g. V. parahaemolyticus was detected at a rate of 50.0% and 22.7% in summer and in winter, respectively. The density of V. parahaemolyticus was significantly higher in summer than in winter, with mean levels of 16.5 MPN/g and 5.0 MPN/g, respectively. Among 145 V. parahaemolyticus isolates examined, none of the isolates possessed tdh and trh. In multiplex PCR-based O-antigen serotyping of these 145 isolates, all serotypes, other than O6, O7, and O9, were detected, and serotype O2 was found to be the most prevalent (detected in 54 isolates). The 145 isolates were grouped into 7 clusters by enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) at a similarity coefficient of 0.66. The antimicrobial resistance patterns of these 145 isolates to 12 antimicrobial agents revealed that most of the isolates were resistant to streptomycin (86.2%), while fewer were resistant to ampicillin (49.6%), cefazolin (43.5%), cephalothin (35.9%), and kanamycin (22.1%). All of the examined isolates were susceptible to azithromycin and chloramphenicol.
The findings of this study will help in defining appropriate monitoring programs, understanding of the dissemination of antibiotic resistant strains, and providing information for the assessment of exposure to this microorganism at the consumption level.
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