Based on the typical Suzuki coupling reaction and Schiff base reaction, a novel fluorescent molecular
PCBW
is synthesized and applied as a fluorescence and colorimetric sensor to detect Cu
2+
in ...aqueous solution. The
PCBW
sensor presents the aggregation-caused quenching (ACQ) effect and at 1 × 10
−5
mol L
−1
it emits the strongest turquoise fluorescence in the DMSO-H
2
O system (
f
w
= 40%). The sensor exhibits a 'turn-off' fluorescent characteristic by adding Cu
2+
, and its fluorescent intensity shows a reliable linear relationship with the Cu
2+
concentration in the range of 0-6 × 10
−6
mol L
−1
, with a detection limit of 1.19 × 10
−8
mol L
−1
. Meanwhile, the
PCBW
sensor also exhibits the colorimetric sensing from colorless to light yellow. The sensor has good selectivity and anti-interference and its pH application range can be extended from 5 to 10. The intramolecular charge transfer (ICT) is speculated as the main fluorescence mechanism of
PCBW
. In addition, the sensor presents good reusability and is practicable to detect Cu
2+
in diverse aqueous samples.
A novel carbazole-based
PCBW
molecule presents excellent fluorometric and colorimetric sensing capacity towards Cu
2+
in a DMSO-H
2
O system (
f
w
= 40%).
Hydrogen sulfide (H
S) is the most important compound causing oral malodor, and its concentration is thought to be closely correlated with oral microorganism activity. Therefore, clarifying the ...correlation between oral microbes and metabolites is important.
This study tested with 16S rRNA gene amplicon and shotgun metagenomic sequencing of oral microorganisms and oral malodor tests.
There were different of the microbial taxa between the low and high H
S groups. And in the high H
S group, most of the enriched taxa were genera which abundance was correlated with H
S concentration. Fusobacterium periodonticum and Prevotella nanceiensis were significantly different in coverage breadth and depth and in LPS biosynthesis contributions between the two groups. The contribution of F. periodonticum to sulfur metabolism was significantly different between the two groups, and the relative F. periodonticum abundance was higher in the high H
S group.
The H
S content is significantly associated with the oral cavity microorganism composition and abundance. Most microorganisms enriched in people with high H
S levels are associated with oral diseases such as caries and periodontal diseases.
The effects of different heat treatment conditions (105, 110, and 120 °C; 10, 20, 30, 40, and 50 min) on the flavor profiles of bamboo shoots were investigated using headspace/solid-phase ...microextraction-gas chromatography/mass spectrometry/olfactometry-odor activity value (HS/SPME-GC/MS/O-OAV) and sensory analysis. Results indicated noticeable differences in the amount and rate of changes in both original and newly produced flavor components in bamboo shoots at different temperatures. The retention rates of hexanal at 105 °C, 110 °C, and 120 °C were 8.55–34.41%, 7.28–34.32%, and 5.22–11.08%, respectively, whereas (E)-2-hexenal, (E, E)-2,4-heptadienal, (E, Z)-2,6-nonadienal, 1-hexanol, 1-octen-3-ol and 2-pentylfuran were mostly lost after heat treatment. The content of three lipid oxidation compounds (octanal, nonanal, and decanal) increased 75.59–500.67%, while the content of newly generated Maillard reaction compounds (e.g. methional, furfural) increased (0–12.58 μg/kg) with heating temperature and time. Sensory analysis indicated that the bamboo shoots heated at 110 °C for 30 min had the best overall flavor. These findings suggested that moderate heat treatment could eliminate some grassy and mushroom flavors from bamboo shoots, enhancing their sweet flavor. This improvement could be favorable for the consumer acceptance of heat-processed bamboo shoots.
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•The overall flavor of bamboo shoots heated at 110 °C for 30 min was most preferred.•Alcohols and aldehydes were decreased by 98.50–98.81% and 44.84–77.37% after heating.•Lipid oxidation compounds (octanal, nonanal and decanal) increased 75.59–500.67% after heating.•The Maillard reaction altered the flavor profile of bamboo shoots, especially at 120 °C.
Summary
Soya protein isolate (SPI)/alginate (ALG)/montmorillonite (MMT)/thymol (THY) nanocomposite films were prepared with a codrying process to enhance the antimicrobial stability. The results ...showed higher gelation point temperature and more stable gelling network were obtained by the addition of MMT. Better thermal stability and sustained release effect was found in the coblended film containing MMT, in which THY release rate at 25 °C decreased with increasing MMT concentration but increased with temperature at a constant relative humidity. The SPI/ALG/THY, SPI/ALG/THY‐CO and SPI/ALG/THY‐CO‐0.6 (MMT content = 0.6 g g−1 SPI) films effectively inhibited the growth of Escherichia coli by 0.95, 0.91 and 0.70 log cfu mL−1 and of Staphylococcus aureus by 0.94, 0.89 and 0.73 log cfu mL−1, respectively, on the surface of raw sausage, compared to the control film.
The addition of montmorillonite could improve the ability of disorderly restructuring of filmogenic solutions, furthermore, through enhancing helix aggregation. The films with montmorillonite effectively inhibited the growth of Escherichia coli and Staphylococcus aureus respectively on the surface of raw sausage, compared to the control film.
A little nicotine in tobacco leaf is non-ionized, which is also known as free-base nicotine (FBN). The dynamic equation existed between FBN and ionized nicotine can easily change with water content, ...temperature and pH value. In this study, a method of the direct quantitative analysis for FBN in tobacco leaf by using headspace solid-phase micro-extraction, combined with gas chromatography/mass spectrometry, was developed. The optimum conditions for analysis method, including sample forms, SPME fiber type, pre-equilibrium temperature, pre-equilibrium time, extraction temperature and extraction time, were investigated in detail. Under the optimized conditions, the linear range of the method was 1 mg/mL–100 mg/mL, with a correlation coefficient (
r
) of 0.9977 and a detection limit of 0.84 μg/g, the repeatability (expressed as relative standard deviation) was 3.35 %, and the recovery of this method was between 99.56 % and 99.80 %. The uncertainty budget was finally done according to the “Guide to the Expression of Uncertainty in Measurement,” and the relative expanded uncertainty was 7.1 % with coverage factor
k
= 2. This method may be reliable and convenient for tobacco control.
In this work, a β-MnO 2 /polypyrrole (β-MnO 2 /PPy) composite was prepared by a facile solvothermal method. The conductivity of the polymer PPy deposited on the surface of MnO 2 can significantly ...improve the electronic conductivity and accommodate the volume change. Compared with pristine β-MnO 2 , β-MnO 2 /PPy exhibited excellent cycling performance and superior rate capability when used as anode for lithium-ion batteries.
BACKGROUNDHydrogen sulfide (H2 S) is the most important compound causing oral malodor, and its concentration is thought to be closely correlated with oral microorganism activity. Therefore, ...clarifying the correlation between oral microbes and metabolites is important. METHODSThis study tested with 16S rRNA gene amplicon and shotgun metagenomic sequencing of oral microorganisms and oral malodor tests. RESULTSThere were different of the microbial taxa between the low and high H2 S groups. And in the high H2 S group, most of the enriched taxa were genera which abundance was correlated with H2 S concentration. Fusobacterium periodonticum and Prevotella nanceiensis were significantly different in coverage breadth and depth and in LPS biosynthesis contributions between the two groups. The contribution of F. periodonticum to sulfur metabolism was significantly different between the two groups, and the relative F. periodonticum abundance was higher in the high H2 S group. CONCLUSIONSThe H2 S content is significantly associated with the oral cavity microorganism composition and abundance. Most microorganisms enriched in people with high H2 S levels are associated with oral diseases such as caries and periodontal diseases.
Genetic algorithm (GA) is a search heuristic that is commonly used for feature selection. The main drawback of GA lies in its unstable results for a random initialization population and background ...correlation; robust results can only be obtained through a series of runs. This paper proposes the use of selected frequency curve (SFC) analysis to evaluate variable importance based on the results of a classical GA. Three statistical parameters are proposed for the quantitative definition of variable importance based on the SFC. The proposed method was applied to three benchmarking datasets obtained from previous works. This was done in conjunction with the use of different regression and classification methods, and the results were compared with those of a classical GA. The results revealed the robustness and superiority of the combination of GA and SFC analyses (GA-SFC) compared with the use of classical GA.
•A robust method, SFC analysis, was proposed for variable selection.•SFC analysis is based on genetic algorithm (GA) but prior to it.•Variable importance could be got in one run GA base on SFC analysis.•Variable importance could be reflected by three statistics based on SFC.
The water sorption, water barrier properties and mechanical behavior of soy protein isolate (SPI) based films combined with propylene glycol alginate (PGA) and lauric acid (La) via a direct- or ...co-dried blending process were investigated. Higher water retention ability and a single glass transition temperature (Tg) were found when the PGA was added to form different ternary co-dried blending films by a co-drying process, indicating their compatibility. Tg was reduced in the case of higher relative humidity and incorporation of La. The response surface methodology (RSM) indicated that the effect of La content was highly significant (p < 0.05) for the water retention ability and mechanical properties, and the proposed models calculated for the tensile strength and elongation at break showed a good fit. The results revealed the importance of the interactions among lipids, protein and polysaccharide in composite films which also provided evidence for modeling film behavior.
In this work, a β-MnO
2
/polypyrrole (β-MnO
2
/PPy) composite was prepared by a facile solvothermal method. The conductivity of the polymer PPy deposited on the surface of MnO
2
can significantly ...improve the electronic conductivity and accommodate the volume change. Compared with pristine β-MnO
2
, β-MnO
2
/PPy exhibited excellent cycling performance and superior rate capability when used as anode for lithium-ion batteries.
The β-MnO
2
/PPy composites were synthesized through
in situ
chemical oxidative polymerization. The β-MnO
2
/PPy exhibit excellent cycling performance and rate capability when used as anode for LIBs.
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