Fructose and its polysaccharides are widely found in fruits and vegetables, with the Maillard reaction of fructose affecting food quality. This study aimed to investigate the Maillard reaction of ...fructose using a fructose⁻histidine model system. The reaction process was characterized using fluorescence spectroscopy and ultraviolet spectroscopy. The effects of temperature, initial reactant concentration, initial fructose concentration, initial histidine concentration, and initial pH value on the different stages of the Maillard reaction were studied. Reactant reduction, ultraviolet and fluorescence spectra, acetic acid content, 5-hydroxymethylfurfural (5-HMF) content, and browning intensity were evaluated. The results showed that increasing the temperature and reactant concentration promoted the condensation reaction of fructose and amino acid in the early stage, the formation of intermediate products with ultraviolet absorption and fluorescence in the intermediate stage, and the formation of pigment in the final stage. The 5-HMF concentration decreased with increasing histidine concentration and initial pH value. Changes in the shape of ultraviolet and fluorescence spectra showed that the initial pH value affected not only the reaction rate, but also the intermediate product types. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging rate of the Maillard reaction products increased with increasing temperature, reactant concentration, and initial pH value.
•A strategy for chemicalome and associated metabolome profiling of Chinese patent drug was performed.•Chemical profiling of Huanghou antidiarrhea dropping pills was firstly analyzed by ...UHPLC-QTOF-MS/MS.•A prototypes-metabolites network of Huanghou antidiarrhea dropping pills was established by biotransformation pathways.•Tissue distributions of active ingredients were explored in colon, liver, heart, spleen, lung and kidney.
Huanghou antidiarrhea dropping pills (HADP) is an efficient Chinese patent drug that is clinically used to treat diarrhea. However, its functional materials remain unclear due to the characteristics of traditional Chinese medicine, which is a multi-component and multi-target complex system. In this study, we investigated the intrinsic chemical components and combined with in vivo metabolism to reveal the functional material basis of HADP. Spectral behavior (accurate molecular weight and secondary fragmentation) and chromatographic behavior (retention time) were key criterions that throughout the whole research of components identification, prototypes screening, and tissue distribution. Mass defect filter (MDF), characteristic product ion filter (PIF), and neutral loss filter (NLF) were other three criterions for metabolites searching. Consequently, a total of 102 components in HADP, including alkaloids, lignans, lactones, gingerols, and alkaloid complexes were identified or tentatively characterized. About 39 metabolites that related to 37 prototypes were calculated and matched in bio-samples. Among them, 14 prototypes and 18 metabolites were detected distribution in colon, liver, heart, spleen, lung or kidney. This study provides a systematic investigation into the metabolism of HADP and offers effective analytical strategies for the characterization of compounds and metabolites in Chinese patent drugs.
This paper investigates the performance of AlGaN/gallium nitride (GaN) MIS high electron mobility transistors (MIS-HEMTs). The gate dielectric layer and the surface passivation layer are formed by ...the low-pressure chemical vapor deposition (LPCVD) Si 3 N 4 . The LPCVD-Si 3 N 4 MIS-HEMTs exhibit a high breakdown voltage (BV) of 1162 V at I DS = 1 μA/mm, a low OFF-state leakage of 7.7 × 10 -12 A/mm, and an excellent ON/OFF-current ratio of ~10 11 . Compared with the static ON-resistance of 2.88 mΩ · cm 2 , the dynamic ON-resistance after high OFF-state drain bias stress at 600 V only increases to 4.89 mΩ · cm 2 . The power device figure of merit = BV 2 /R ON.sp is calculated to be 469 MW · cm -2 . The LPCVD-Si 3 N 4 /GaN interface state density is in the range of (1.4-5.3) × 10 13 eV -1 cm -2 extracted by the conventional conductance method. Finally, the gate insulator degradation of GaN-based MIS-HEMTs is analyzed by time-dependent dielectric breakdown test. The lifetime is extrapolated to 0.01% of failures after ten years at 300 K by fitting the data with a power law to a gate voltage of 10.1 V.
This study aimed to investigate the relationship between MMP-2, TIMP-1, β2-MG, hs-CRP and the progression of type 2 diabetic retinopathy (T2DM). For this purpose, 68 patients with T2DM retinopathy ...treated in our hospital were selected as the retinopathy group (REG), and 68 T2DM patients without retinopathy were selected as the control group (CDG). The serum levels of MMP-2, TIMP-1, β2-MG and hs-CRP were compared between the two groups. According to the international clinical classification of T2DM non-retinopathy (NDR), the patients were divided into non-proliferative T2DM retinopathy group (NPDR) (n=28) and proliferative T2DM retinopathy group (PDR) (n=40). The levels of MMP-2, TIMP-1, β2-MG and hs-CRP in patients with different conditions were compared. In addition, the Spearman method was used to analyze the correlation between the levels of MMP-2, TIMP-1, β2-MG, hs-CRP and glucose and lipid metabolism and the course of disease in patients with T2DM retinopathy (DR). Logistic multiple regression was used to analyze the risk factors of DR. Results showed that the levels of serum MMP-2, β2-MG and hs-CRP in PDR groups were raised than those in NPDR and NDR, while the serum TIMP-1 level was reduced. The levels of MMP-2, β2-MG and hs-CRP were positively correlated with the levels of HbA1c, TG and the course of disease in DR patients, while the levels of TIMP-1 in DR patients were negatively correlated with the levels of HbA1c, TG and the course of disease. The results of multivariate Logistic regression model showed that MMP-2, β2-MG and hs-CRP were independent risk factors for DR, and TIMP-1 was the protective factor for DR. In conclusion, the changes of peripheral blood MMP-2, TIMP-1, hs-CRP and β2-MG levels are closely related to the progression of T2DM retinopathy.
Soil contamination with potentially toxic elements (PTEs) is an increasing environmental problem, posing serious threats to the living organisms. Phytoremediation is a sustainable and highly accepted ...technology for remediation of PTE-contaminated soils. Alfalfa has been widely adopted for the phytoremediation of PTE-contaminated soils due to its large biomass productivity, high PTE tolerance, and strong capacity to take up PTEs. However, there are still no literature reviews systematically summarized the potential of alfalfa in the phytoremediation. Therefore, we review the available literatures that present its PTE uptake, phytotoxicity, tolerance mechanisms, and aided techniques improving the phytoremediation efficiency. In this review, alfalfa shows high amounts of PTEs accumulation, especially in their root tissue. Meanwhile, the inner mechanisms of PTE tolerance and accumulation in alfalfa are discussed including: (i) the activation of antioxidant enzyme system, (ii) subcellular localization, (iii) production of glutathione, phytochelatins, and proline, and (iv) regulation of gene expression. Indeed, excessive PTE can overcome the defense system, which causes oxidative damage in alfalfa plants, thereby inhibiting growth and physiological processes and weakening the ability of PTE uptake. Till now, several approaches have been developed to improve the tolerance and/or accumulation of PTE in alfalfa plants as follows: (i) selection of PTE tolerant cultivars, (ii) applying plant growth regulators, (iii) addition of chelating agents, fertilizer, and biochar materials, and (iv) inoculation of soil microbes. Finally, we indicate that the selection of PTE-tolerant cultivars along with inoculation of soil microbes may be an efficient and eco-friendly strategy of the soil PTE phytoremediation.
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•Alfalfa can be considered a potential candidate for phytoremediation of potentially toxic elements (PTE)-contaminated soils.•Alfalfa plants have evolved various mechanisms to tolerate PTE stress.•PTEs from the soil can be markedly accumulated in alfalfa plants.•Assisted measures can increase the phytoremediation efficiency.
•Long-range airborne transmission in the restaurant is fully supported.•Fomite and close contact routes in the Guangzhou restaurant outbreak are ruled out.•Diners and staffs spent 20% of their time ...on close contact in the restaurant.•Diners and staffs spent 90% of their time touching surfaces in the restaurant.•Almost no close contact happened between diners from different tables.
Background: Coronavirus disease 2019 (COVID-19) is primarily a respiratory disease that has become a global pandemic. Close contact plays an important role in infection spread, while fomite may also be a possible transmission route. Research during the COVID-19 pandemic has identified long-range airborne transmission as one of the important transmission routes although lack solid evidence.
Methods: We examined video data related to a restaurant associated COVID-19 outbreak in Guangzhou. We observed more than 40,000 surface touches and 13,000 episodes of close contacts in the restaurant during the entire lunch duration. These data allowed us to analyse infection risk via both the fomite and close contact routes.
Results: There is no significant correlation between the infection risk via both fomite and close contact routes among those who were not family members of the index case. We can thus rule out virus transmission via fomite contact and interpersonal close contact routes in the Guangzhou restaurant outbreak. The absence of a fomite route agrees with the COVID-19 literature.
Conclusions: These results provide indirect evidence for the long-range airborne route dominating SARS-CoV-2 transmission in the restaurant. We note that the restaurant was poorly ventilated, allowing for increasing airborne SARS-CoV-2 concentration.
A new rhodamine-based fluorescent probe RFP3 was synthesized for selective recognition Hg2+ and Cu2+ in EtOH–HEPES buffer solution (20.0mM HEPES, 30:70, v/v, pH 7.0). This reagent could be used as a ...dual probe and allowed detection of Cu2+ and Hg2+ by monitoring changes in absorption and the fluorescence spectral pattern. UV–vis spectroscopy indicates that RFP3 is a good chromogenic chemosensor for Cu2+. Whereas the other ions, such as Na+, K+, Mg2+, Fe3+, Ca2+, Zn2+, Pb2+, Hg2+, Cd2+, Ba2+, Ni2+, Mn2+ and Ag+ failed to generate a palpable response. However, the color solution of RFP3 caused by the binding of Cu2+ has no fluorescence, which may be ascribed to the quenching of the fluorescence by Cu2+. Fluorescence spectral data reveals that RFP3 is an excellent fluorescent chemosensor for Hg2+ and other metal ions show no obvious interference for Hg2+ detection. Finally, RFP3 was successfully applied to the imaging of Hg2+ in living HL-7702 cells.
In the study, Z-scheme CdS/BiOCl visible light reactive photocatalysts were prepared by a one-step synthesis. The composition, morphology, optical absorption property and degradation mechanism of as ...obtained binary composites were investigated in detail. SEM, TEM and XPS observation indicated that CdS nanoparticles were well dispersed on BiOCl nanosheets and bounded chemically to BiOCl. The CdS/BiOCl composite photocatalysts showed the enhanced photocatalytic performance on degrading RhB under visible light irradiation. Among them, 5-CdS/BiOCl exhibited the highest degradation rate (up to 94%), which was 1.9 and 4.7 times higher than those of CdS and BiOCl, respectively. And the performance of 5-CdS/BiOCl photocatalyst remained stable after four replicate experiments. The prime causes for the improved capability of CdS/BiOCl photocatalysts were their low carrier recombination and extended light response range. A feasible Z-scheme heterojunction mechanism was revealed according to radical capture experiments and photoelectrochemical tests. This study provides a new idea for wastewater purification.
Soil shrinkage commonly occurs during centrifugation for soil water retention curve (SWRC) measurement. This phenomenon increases bulk density and results in a deviation of the SWRC from the true ...curve, reducing the accuracy of soil water movement simulations. This study considers the change in bulk density during SWRC measurement and corrects for it. Five soils, classified as either loam or sandy loam, were selected as experimental samples from Liaoning, Yunnan, Xinjiang, Shandong, and Shaanxi Provinces of China. Corrected and uncorrected SWRCs were employed in cumulative infiltration simulations to determine whether such a correction is necessary. Results showed that the sample heights decreased as the linear shrinkage ratios increased during dehydration; bulk densities increased relative to the designated values and altered the SWRC. The values of soil moisture for the corrected SWRC were always higher than those for uncorrected SWRC, with an average increment of 6%–18%. SWMS_2D simulations predicted the observed cumulative infiltration values more accurately when using the corrected SWRC than when using the uncorrected SWRC according to the smaller percent bias, root mean square error, and mean absolute percentage error. The results suggested that a correction of the SWRC for changes in bulk density is necessary.
•Combination of soil shrinkage and soil water retention curve (SWRC) measurement•SWRC is corrected on the basis of the change of bulk density.•A correction of SWRC is necessary in simulation of soil water movement.
The pyrolysis and combustion characteristics of urea-formaldehyde resin (UFR) residue were investigated by using thermogravimetric analysis, coupled with Fourier transform infrared spectroscopy ...(TG-FTIR). It is indicated that the pyrolysis process can be subdivided into three stages: drying the sample, fast thermal decomposition and further cracking process. The total weight loss of 90
wt.% at 950
°C is found in pyrolysis, while 74
wt.% of the original mass lost in the second stage is between 195
°C and 430
°C. The emissions of carbon dioxide, isocyanic acid, ammonia, hydrocyanic acid and carbon monoxide are identified in UFR residue pyrolysis, moreover, isocyanic acid emitted at low temperature is found as the most important nitrogen-containing gaseous product in UFR residue pyrolysis, and there is a large amount of hydrocyanic acid emitted at high temperature. The similar TG and emission characteristics as the first two stages during pyrolysis are found in UFR residue combustion at low temperature. The combustion process almost finishes at 600
°C; moreover, carbon dioxide and water are identified as the main gaseous products at high temperature. It is indicated that the UFR residue should be pyrolyzed at low temperature to remove the initial nitrogen, and the gaseous products during pyrolysis should be burnt in high temperature furnace under oxygen-rich conditions for pollutant controlling.
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