The value of bioimpedance analysis in the assessment of hydration and nutritional status in children on chronic peritoneal dialysis

Bioimpedance analysis (BIA)-body composition monitoring (BCM) has been used to evaluate the hydration and nutritional status of adults and children on dialysis. However, its clinical application still has challenges, so further exploration is valuable. We used BIA-BCM to evaluate the hydration and nutritional status of children undergoing chronic peritoneal dialysis from 1 July 2021 to 31 December 2022 in the Children's Hospital of Fudan University to explore the clinical value of this method. A total of 84 children on chronic peritoneal dialysis (PD) were included. In the PD group, 16 (19.05%) and 31 (36.90%) had mild and severe overhydration (OH), respectively; 41.27% (26/63) had a low lean tissue index (LTI). In the PD group, patients with relative OH (Re-OH) > 5.6% had significantly higher systolic blood pressure (SBP) and SBP z score (SBPz). Patients with LTI > 12% had significantly higher body mass index (BMI) and BMI z score (BMIz). Canonical correlation analysis indicated a linear relationship (ρ = 0.708) between BIA-BCM hydration and the clinical hydration indicator and a linear relationship (ρ = 0.995) between the BIA-BCM nutritional indicator and the clinical nutritional indicator. A total of 56% of children on chronic peritoneal dialysis had OH, and 41% had a low LTI. In PD patients, SBP and SBPz were correlated with BIA-BCM Re-OH, and BMI and BMIz were correlated with BIA-BCM LTI. BIA-BCM indicators have good clinical value in evaluating hydration and nutrition.

The effects of CYP2B6 inactivators on the metabolism of ciprofol

Ciprofol is a novel short-acting intravenous anaesthetic developed in China that is mainly metabolized by cytochrome P450 2B6 (CYP2B6) and uridine diphosphate glucuronosyltransferase 1A9 (UGT1A9). Currently, insufficient evidence is available to support drug‒drug interactions between ciprofol and CYP2B6 inactivators. Here, we established a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method to assess the concentration of ciprofol and investigated the effects of psoralen and clopidogrel on the metabolism of ciprofol in liver microsomes and rats. In rat and human liver microsomes, the median inhibitory concentration (IC50) values of psoralen were 63.31 μmol·L-1 and 34.05 μmol·L-1, respectively, showing mild inhibitory effects on ciprofol metabolism, whereas the IC50 values of clopidogrel were 6.380 μmol·L-1 and 2.565 μmol·L-1, respectively, with moderate inhibitory effects. SD rats were randomly divided into three groups: psoralen (27 mg·kg-1), clopidogrel (7.5 mg·kg-1), and the same volume of 0.5% carboxy methyl cellulose. After 7 days, all rats were injected with 2.4 mg·kg-1 ciprofol. Compared with the control group, the AUC and MRT values of ciprofol in the psoralen and clopidogrel groups were significantly greater, whereas the CL values were significantly lower. In addition, the durations of loss of righting reflex (LORR) in the psoralen and clopidogrel groups were 16.1% and 23.0% longer than that in the control group, respectively. In conclusion, psoralen and clopidogrel inhibit ciprofol metabolism to different degrees and prolong the duration of LORR in rats.

Development of Zanthoxylum bungeanum essential oil Pickering emulsions using potato protein-chitosan nanoparticles and its application in mandarin preservation

This study aimed to develop Pickering emulsions for the encapsulation of Zanthoxylum bungeanum essential oil (ZBEO) using potato protein-chitosan composite nanoparticles (PCCNs). The sustained release properties of ZBEO, antifungal efficacy, and preservation effects of formulated ZBEO-Pickering emulsions (ZBEO-PEs) on mandarins were evaluated. Particle size, zeta potential, emulsifying activity (EAI), and emulsifying stability (ESI) analysis showed that PCCNs prepared with the potato protein to chitosan mass ratio of 10:3 provided optimal emulsification and stabilization. Techniques such as differential scanning calorimetry (DSC), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR) demonstrated that chitosan introduction increased the wettability of potato protein through electrostatic, hydrogen bonding, and hydrophobic interactions. ZBEO-PEs formulated with 3.0 % PCCNs and an oil fraction of 0.40 showed best encapsulation efficiency, storage stability and sustained release. Confocal laser scanning microscopy confirmed the adsorption of PCCNs, forming dense interface layers on the surface of oil droplets, thereby enhancing the stability of ZBEO-PEs. In vitro experiments demonstrated enhanced antifungal activity of ZBEO-PEs against Penicillium italicum and Penicillium digitatum. Additionally, storage experiments indicated that ZBEO-PEs coatings effectively controlled postharvest decay caused by Penicillium spp. in mandarins. Overall, the findings suggest that PCCNs are highly efficient emulsifiers for ZBEO Pickering emulsions, underscoring their potential as preservative coatings for mandarins.

Membrane HIV-1 envelope glycoproteins stabilized more strongly in a pretriggered conformation than natural virus Envs

The pretriggered conformation of the human immunodeficiency virus (HIV-1) envelope glycoprotein (Env) trimer ((gp120/gp41)3) is targeted by virus entry inhibitors and broadly neutralizing antibodies (bNAbs). The lability of pretriggered Env has hindered its characterization. Here, we produce membrane Env variants progressively stabilized in pretriggered conformations, in some cases to a degree beyond that found in natural HIV-1 strains. Pretriggered Env stability correlated with stronger trimer subunit association, increased virus sensitivity to bNAb neutralization, and decreased capacity to mediate cell-cell fusion and virus entry. For some highly stabilized Env mutants, after virus-host cell engagement, the normally inaccessible gp120 V3 region on an Env intermediate became targetable by otherwise poorly neutralizing antibodies. Thus, evolutionary pressure on HIV-1 Env to maintain trimer integrity, responsiveness to the CD4 receptor, and resistance to antibodies modulates pretriggered Env stability. The strongly stabilized pretriggered membrane Envs reported here will facilitate further characterization of this functionally important conformation.

The mysteries of pharmacokinetics and in vivo metabolism of Oroxylum indicum (L.) Kurz: A new perspective from MSOP method

The pharmacological effects of flavonoids in Oroxylum indicum (L.) Kurz against inflammation, bacterial, and oxidation have been well-documented. Additionally, it is commonly consumed as tea. However, the in vivo mechanism of its main compounds has not been well elucidated. In this study, a highly selective and sensitive UHPLC-Q-TOF-MS method combined with Mass Spectrum-based Orthogonal Projection (MSOP) theory and four-step analytical strategy was established and validated to identify metabolites in rats following oral administration Oroxylum indicum (L.) Kurz extract. Furthermore, a sensitive LC-MS/MS method was developed and validated for the first time to analyze the pharmacokinetics of ten main flavonoids in rats. Notably, a total of 47 metabolites were identified in blood, bile, urine, and feces samples. The maximum plasma concentration (Cmax) values for oroxin A, oroxin B, baicalin, chrysin, baicalein, scutellarein, apigenin, quercetin oroxylin A and isorhamnetin were 2945.1 ± 11.23 ng/mL, 3123.9 ± 16.37 ng/mL, 130.40 ± 27.52 ng/mL, 117.20 ± 28.54 ng/mL, 64.12 ± 19.33 ng/mL, 97.22 ± 24.27 ng/mL, 145.22 ± 29.92 ng/mL, 45.19 ± 18.84 ng/mL, 67.32 ± 15.78 ng/mL and 128.44 ± 26.42 ng/mL. A double peak was observed in the drug-time curve of apigenin, due to enterohepatic recirculation. This study demonstrated that MSOP method provided more technical support for the identification of flavonoid metabolites in complex system than traditional methods.

Impact of microorganisms on key processes of organic acid metabolism during the occurrence and disappearance of paocai pellicle

In vegetable fermentation, pellicle is a common quality deterioration phenomenon. This study investigates the characteristics of glucose, organic acids, amino acids, and biogenic amines during the pellicle occurrence and disappearance of paocai. The results revealed a slight increase in pH of the fermentation system after pellicle occurred, and glucose was the main carbohydrate that microbial activity primary relied on. The microorganisms responsible for pellicle formation consumed organic acids in brine, but the lactic acid in paocai gradually increased and exceeded 25 mg/g. The appearance of pellicle caused a decrease in total free amino acids from 200.390 mg/100 g to 172.079 when pellicle occurred, whereas its impact on biogenic amines was not apparent. Through Kyoto Encyclopedia of Genes and Genomes pathway enrichment of metagenomics sequencing data, screening, and sorting of the key enzymes involved in organic acid metabolism, it was observed that the composition and species of the key microorganisms capable of metabolizing organic acids were more abundant before the appearance of pellicle. When pellicle occurred, lactic acid may be metabolized by Lactobacillus plantarum; in contrast, Lactobacillus and Pichia were associated with citric acid metabolism, and Lactobacillus, Pichia, Saccharomycodes, and Kazachstania were linked to malic acid metabolism. Moreover, Prevotella, Kazachstania, Lactobacillus, Vibrio, and Siphonobacter were implicated in succinic acid metabolism. Additionally, the production of tartaric acid and oxalic acid in paocai and brine resulted from abiotic effects. This knowledge offers a theoretical basis for precise control of paocai fermentation process. PRACTICAL APPLICATION: Our study revealed the specific situation of the metabolites produced by the microorganisms during the pollution and recovery process of pellicle in paocai fermentation, especially the effect of pellicle on the key process of organic acid metabolism. These research results provided theoretical basis for precise control of paocai fermentation.

Antibiotics affect the pharmacokinetics of n-butylphthalide in vivo by altering the intestinal microbiota

OBJECTIVE

N-butylphthalide (NBP) is a monomeric compound extracted from natural plant celery seeds, whether intestinal microbiota alteration can modify its pharmacokinetics is still unclear. The purpose of this study is to investigate the effect of intestinal microbiota alteration on the pharmacokinetics of NBP and its related mechanisms.

METHODS

After treatment with antibiotics and probiotics, plasma NBP concentrations in SD rats were determined by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The effect of intestinal microbiota changes on NBP pharmacokinetics was compared. Intestinal microbiota changes after NBP treatment were analyzed by 16S rRNA sequencing. Expressions of CYP3A1 mRNA and protein in the liver and small intestine tissues under different intestinal flora conditions were determined by qRT-PCR and Western Blot. KEGG analysis was used to analyze the effect of intestinal microbiota changes on metabolic pathways.

RESULTS

Compared to the control group, the values of Cmax, AUC0-8, AUC0-∞, t1/2 in the antibiotic group increased by 56.1% (P<0.001), 56.4% (P<0.001), 53.2% (P<0.001), and 24.4% (P<0.05), respectively. In contrast, the CL and Tmax values decreased by 57.1% (P<0.001) and 28.6% (P<0.05), respectively. Treatment with antibiotics could reduce the richness and diversity of the intestinal microbiota. CYP3A1 mRNA and protein expressions in the small intestine of the antibiotic group were 61.2% and 66.1% of those of the control group, respectively. CYP3A1 mRNA and protein expressions in the liver were 44.6% and 63.9% of those in the control group, respectively. There was no significant change in the probiotic group. KEGG analysis showed that multiple metabolic pathways were significantly down-regulated in the antibiotic group. Among them, the pathways of drug metabolism, bile acid biosynthesis and decomposition, and fatty acid synthesis and decomposition were related to NBP biological metabolism.

CONCLUSION

Antibiotic treatment could affect the intestinal microbiota, decrease CYP3A1 mRNA and protein expressions and increase NBP exposure in vivo by inhibiting pathways related to NBP metabolism.

[Analysis of loss to follow-up status and influencing factors of children born to pregnant women with HIV infection in China in 2019]

Objective: To understand the loss to follow-up of children born to pregnant women with HIV infection (HIV-exposed children) and analyze its influencing factors in China in 2019. Methods: The data were collected from the follow-up records of pregnant women with HIV infection and their children reported by the national "Management Information System for the Prevention of HIV, syphilis and Hepatitis B Mother-to-Child Transmission" in 2019. HIV-exposed children were defined as those who were not followed up after birth or who were not followed up at 18 months of age and who were not followed up at 21 months of age. The univariate and multivariate influencing factors of loss to follow-up of children born to HIV-infected pregnant women were analyzed by χ2 test and logistic regression model. SPSS 25.0 software was used for statistical analysis. Results: The number of HIV-infected pregnant women was 5 039, the number of live-born children was 5 035, the number of loss to follow-up children within 18 months of age was 283, and the loss to follow-up rate children was 5.62%(283/5 035). The results of multivariate logistic regression analysis showed that the rate of loss to follow-up of exposed children born to pregnant women who worked as farmers (animal husbandry and fishery) (aOR=0.34, 95%CI: 0.22-0.53), unmarried (aOR=0.47, 95%CI: 0.24-0.93), first marriage (aOR=0.38, 95%CI: 0.22-0.67), remarriage (aOR=0.36, 95%CI: 0.20-0.67) and cohabiting (aOR=0.47, 95%CI: 0.23-0.97), and knew they had HIV infection before this pregnancy (aOR=0.53, 95%CI: 0.40-0.70) was lower. Han nationality (aOR=1.52, 95%CI: 1.09-2.13), primary school (aOR=2.06, 95%CI: 1.10-3.89) and junior middle school (aOR=1.81, 95%CI: 1.03-3.17) educational level, non-use of antiviral drugs (aOR=6.21, 95%CI: 4.32-8.93) and delivery in township (street) level midwifery institutions (aOR=5.72, 95%CI: 1.61-20.27) had higher rates of loss to follow-up among infants born to HIV-infected pregnant women. Conclusions: HIV-exposed children still have a specific rate of loss to follow-up in China in 2019. In order to further reduce the rate of loss to follow-up, it is of great significance to improve the detection rate of HIV before pregnancy and the rate of antiviral drugs used in pregnant women with HIV infection, which is of great significance for the effective implementation of comprehensive intervention measures of prevention of mother-to-child transmission of HIV.

QTL mapping and genomic selection of stem and branch diameter in soybean (Glycine max L.)

Introduction

Soybean stem diameter (SD) and branch diameter (BD) are closely related traits, and genetic clarification of SD and BD is crucial for soybean breeding.

Methods

SD and BD were genetically analyzed by a population of 363 RIL derived from the cross between Zhongdou41 (ZD41) and ZYD02878 using restricted two-stage multi-locus genome-wide association, inclusive composite interval mapping, and three-variance component multi-locus random SNP effect mixed linear modeling. Then candidate genes of major QTLs were selected and genetic selection model of SD and BD were constructed respectively.

Results and discussion

The results showed that SD and BD were significantly correlated (r = 0.74, P < 0.001). A total of 93 and 84 unique quantitative trait loci (QTL) were detected for SD and BD, respectively by three different methods. There were two and ten major QTLs for SD and BD, respectively, with phenotypic variance explained (PVE) by more than 10%. Within these loci, seven genes involved in the regulation of phytohormones (IAA and GA) and cell proliferation and showing extensive expression of shoot apical meristematic genes were selected as candidate genes. Genomic selection (GS) analysis showed that the trait-associated markers identified in this study reached 0.47-0.73 in terms of prediction accuracy, which was enhanced by 6.56-23.69% compared with genome-wide markers. These results clarify the genetic basis of SD and BD, which laid solid foundation in regulation gene cloning, and GS models constructed could be potentially applied in future breeding programs.

Self-Supervised Image Denoising of Third Harmonic Generation Microscopic Images of Human Glioma Tissue by Transformer-based Blind Spot (TBS) Network

Third harmonic generation (THG) microscopy shows great potential for instant pathology of brain tumor tissue during surgery. However, due to the maximal permitted exposure of laser intensity and inherent noise of the imaging system, the noise level of THG images is relatively high, which affects subsequent feature extraction analysis. Denoising THG images is challenging for modern deep-learning based methods because of the rich morphologies contained and the difficulty in obtaining the noise-free counterparts. To address this, in this work, we propose an unsupervised deep-learning network for denoising of THG images which combines a self-supervised blind spot method and a U-shape Transformer using a dynamic sparse attention mechanism. The experimental results on THG images of human glioma tissue show that our approach exhibits superior denoising performance qualitatively and quantitatively compared with previous methods. Our model achieves an improvement of 2.47-9.50 dB in SNR and 0.37-7.40 dB in CNR, compared to six recent state-of-the-art unsupervised learning models including Neighbor2Neighbor, Blind2Unblind, Self2Self+, ZS-N2N, Noise2Info and SDAP. To achieve an objective evaluation of our model, we also validate our model on public datasets including natural and microscopic images, and our model shows a better denoising performance than several recent unsupervised models such as Neighbor2Neighbor, Blind2Unblind and ZS-N2N. In addition, our model is nearly instant in denoising a THG image, which has the potential for real-time applications of THG microscopy.

N-Butylphthalide Potentiates the Effect of Fluconazole Against Drug-Resistant Candida glabrata and Candida tropicalis. Evidence for Its Mechanism of Action

Objective

To define the antifungal activity of n-butylphthalide alone or in combination with fluconazole in Candida glabrata and Candida tropicalis.

Methods

The antifungal activity of n-butylphthalide alone and in combination with fluconazole was investigated by the classical broth microdilution method and the time-killing curve method. The QRT-PCR method was used to determine gene expressions changes of mitochondrial respiratory chain enzymes, drug efflux pumps and drug target enzymes in Candida glabrata and Candida tropicalis after n-butylphthalide treatment.

Results

The MIC values of n-butylphthalide against Candida glabrata and Candida tropicalis ranged from 16 to 64 μg·mL-1. The FICI value of the combination of n-butylphthalide and fluconazole against drug-resistant Candida glabrata and Candida tropicalis ranged from 0.5001 to 0.5315 with partial synergism. Time-killing curves showed that 256 μg·mL-1 n-butylphthalide significantly inhibited the growth of drug-resistant colonies of Candida glabrata and Candida tropicalis, and 128 μg·mL-1 n-butylphthalide combined with 1 μg·mL-1 fluconazole had an additive effect. N-butylphthalide could alter the expression of mitochondrial respiratory chain enzymes COX1, COX2, COX3, and CYTB genes in Candida glabrata and Candida tropicalis (P< 0.05) and downregulate the expression of the drug efflux pump genes CDR1 and CDR2 in drug-resistant Candida glabrata to 3.36% and 3.65%, respectively (P<0.001), but did not affect the drug target enzyme ERG11 in drug-resistant Candida tropicalis.

Conclusion

N-butylphthalide had antifungal activity against Candida glabrata and Candida tropicalis. N-butylphthalide improved the activity of fluconazole against drug-resistant Candida glabrata by affecting the expression of mitochondrial respiratory chain enzyme genes and reversing the high expression of drug efflux pump genes CDR1 and CDR2.

Comprehensive profiling of enhancer RNA in stage II/III colorectal cancer defines two prognostic subtypes with implications for immunotherapy

BACKGROUND

Recently, enhancer RNAs (eRNAs) have garnered attention as pivotal biomarkers for the onset and progression of cancer. However, the landscape of eRNAs and the implications of eRNA-based molecular subtypes in stage II/III colorectal cancer (CRC) remain largely unexplored.

METHODS

Comprehensive profiling of eRNAs was conducted on a public stage II/III CRC cohort with total RNA-seq data. We used unsupervised clustering of prognostic eRNAs to establish an eRNA-based subtyping system. Further evaluations included molecular characteristics, immune infiltration, clinical outcomes, and drug responses. Finally, we validated the eRNA-based subtyping system in The Cancer Genome Atlas (TCGA) CRC cohort.

RESULTS

We identified a total of 6453 expressed eRNAs, among which 237 were prognostic. A global upregulation of eRNAs was observed in microsatellite-stable (MSS) CRCs when compared to microsatellite instability-high (MSI-H) CRCs. Through consensus clustering, two novel molecular subtypes, termed Cluster 1(C1) and Cluster 2(C2), were further identified. C1, associated with the activation of epithelial-mesenchymal transition (EMT), hypoxia, and KRAS signaling pathways, showed poorer prognosis. C2, correlated with the canonical CRC subtype, exhibited superior survival outcomes. In addition, C1 showed enrichment with immune infiltration and more sensitivity to immune checkpoint inhibitors.

CONCLUSION

Our study unravels the molecular heterogeneity of stage II/III CRC at the eRNA level and highlights the potential applications of the novel eRNA-based subtyping system in predicting prognosis and guiding immunotherapy.

Incorporation of cellulose nanocrystals to improve the physicochemical and bioactive properties of pectin-konjac glucomannan composite films containing clove essential oil

This study aimed to investigate the effectiveness of cellulose nanocrystals (CNC) isolated from cotton in augmenting pectin (PEC)/konjac glucomannan (KGM) composite films containing clove essential oil (CEO) for food packaging application. The effects of CNC dosage on film properties were examined by analyzing the rheology of film-forming solutions and the mechanical, barrier, antimicrobial, and CEO-release properties of the films. Rheological and FTIR analysis revealed the enhanced interactions among the film components after CNC incorporation due to its high aspect ratio and abundant hydroxyl groups, which can also prevent CEO droplet aggregation, contributing to form a compact microstructure as confirmed by SEM and 3D surface topography observations. Consequently, the addition of CNC reinforced the polysaccharide matrix, increasing the tensile strength of the films and improving their barrier properties to water vapor. More importantly, antibacterial, controlled release and kinetic simulation experiments proved that the addition of CNC could further slow down the release rate of CEO, prolonging the antimicrobial properties of the films. PEC/KGM/CEO composite films with 15 wt% CNC was found to have relatively best comprehensive properties, which was also most effective in delaying deterioration of grape quality during the storage of 9 days at 25 °C.

Hydrocarbon adsorption mechanism of modern automobile engines and methods of reducing hydrocarbon emissions during cold start process: A review

With the global emphasis on environmental protection and increasingly stringent emission regulations for internal combustion engines, there is an urgent need to overcome the problem of large hydrocarbon (HC) emissions caused by unstable engine cold starts. Synergistic engine pre-treatment (reducing hydrocarbon production) as well as after-treatment devices (adsorbing and oxidizing hydrocarbons) is the fundamental solution to emissions. In this paper, the improvement of hydrocarbon emissions is summarized from two aspects: pre-treatment and after-treatment. The pre-treatment for engine cold start mainly focuses on summarizing the intake control, fuel, and engine timing parameters. The after-treatment mainly focuses on summarizing different types of adsorbents and modifications (mainly including different molecular sieve structures and sizes, preparation conditions, silicon aluminum ratio, ion exchange modification, and heterogeneity, etc.), adsorptive catalysts (mainly including optimization of catalytic performance and structure), and catalytic devices (mainly including coupling with thermal management equipment and HC trap devices). In this paper, a SWOT (strength, weakness, opportunity, and threat) analysis of pre-treatment and after-treatment measures is conducted. Researchers can obtain relevant research results and seek new research directions and approaches for controlling cold start HC emissions.

Localized Medium Concentration Electrolyte with Fast Kinetics for Lithium Metal Batteries

Localized high-concentration electrolyte is widely acknowledged as a cutting-edge electrolyte for the lithium metal anode. However, the high fluorine content, either from high-concentration salts or from highly fluorinated diluents, results in significantly higher production costs and an increased environmental burden. Here, we have developed a novel electrolyte termed "Localized Medium-Concentration Electrolyte" (LMCE) to effectively address these issues. This LMCE is designed and produced by diluting a medium concentration (0.5 M-1.5 M) electrolyte which is incompatible with lithium metal anode before diluting. It has ultralow concentration (0.1 M) and demonstrates remarkable compatibility with lithium metal anode. Surprisingly, our LMCE, despite having an ultralow concentration (0.1 M), exhibits excellent kinetics in Li/Cu, Li/Li, LiFePO4 /Li, and NCM811/Li batteries. Additionally, LMCE effectively inhibits the corrosion of the Al current collector caused by LiTFSI salt under high voltage (>4 V) conditions. This groundbreaking LMCE design transforms the seemingly "incompatible" into the "compatible", opening up new avenues for exploring various electrolyte formulations, including all liquid electrolyte-based batteries.

Dual-mode fluorescence and colorimetric sensing of sulfide anion in natural water based on near-infrared Ag2S quantum dots and MnO2 nanosheets complex

Near infrared (NIR) emission Ag2S quantum dots (QDs) are of great value for biochemical sensing with strong anti-interference and low toxicity. Herein, NIR fluorescence Ag2S QDs were synthesized successfully. Combined with the excellent oxidase-like characteristics of manganese dioxide (MnO2) nanosheets, a fluorescence and colorimetric dual-mode sensor for sulfide anion was developed. MnO2 nanosheets could effectively catalyze the oxidation of TMB to produce blue TMB oxide (ox TMB), at the same time, the fluorescence of Ag2S QDs could be effectively quenched by fluorescence internal filtration effect (IFE) and dynamic quenching effect. The enzyme-like activity was weakened and the NIR fluorescence of Ag2S QDs was restored when sulfide anion (S2-) was added, due to the reduction of MnO2 to Mn2+.The linear ranges for fluorescence and colorimetric analysis of S2- were 2-250 μM and 0.3-50 μM, with detection limits of 0.6 and 0.215 μM, correspondingly. The dual-mode sensor had a wider detection range, higher sensitivity and shorter reaction time, which could be used for highly selective detection of S2- in different concentration ranges. In addition, it had been successfully applied to the determination of sulfide in water samples with satisfactory accuracy and sensitivity.

The switch of the DNA tetrahedral tweezers controlled by mercury ions

In this paper, the one-pot method is used to make the four DNA strands complement each other to construct the basic framework for DNA tetrahedral tweezers. To regulate the opening and closing of DNA tetrahedral tweezers, DNA strands with a high amount of T-base sequences is partially complementary to the tetrahedral framework. Hg2+ can form T-Hg-T hairpin structures with T-base. When DNA tetrahedral tweezers encounter Hg2+, the T-Hg-T structure is formed to shorten the connecting chain, and the tightening force causes the DNA tweezers to change from an open state to a closed state. Conversely, changes in fluorescence intensity due to the structure change can be used to detect the presence of Hg2+.

Overview of mechanisms of Fe-based catalysts for the selective catalytic reduction of NOx with NH3 at low temperature

With the increasingly stringent control of NOx emissions, NH3-SCR, one of the most effective de-NOx technologies for removing NOx, has been widely employed to eliminate NOx from automobile exhaust and industrial production. Researchers have favored iron-based catalysts for their low cost, high activity, and excellent de-NOx performance. This paper takes a new perspective to review the research progress of iron-based catalysts. The influence of the chemical form of single iron-based catalysts on their performance was investigated. In the section on composite iron-based catalysts, detailed reviews were conducted on the effects of synergistic interactions between iron and other elements on catalytic performance. Regarding loaded iron-based catalysts, the catalytic performance of iron-based catalysts on different carriers was systematically examined. In the section on iron-based catalysts with novel structures, the effects of the morphology and crystallinity of nanomaterials on catalytic performance were analyzed. Additionally, the reaction mechanism and poisoning mechanism of iron-based catalysts were elucidated. In conclusion, the paper delved into the prospects and future directions of iron-based catalysts, aiming to provide ideas for the development of iron-based catalysts with better application prospects. The comprehensive review underscores the significance of iron-based catalysts in the realm of de-NOx technologies, shedding light on their diverse forms and applications. The hope is that this paper will serve as a valuable resource, guiding future endeavors in the development of advanced iron-based catalysts.

Research and optimization of hydrogen addition and EGR on the combustion, performance, and emission of the biodiesel-hydrogen dual-fuel engine with different loads based on the RSM

Pollutants produced by engines are a significant source of environmental pollution, so the study of engine emissions is very important. In this study, with CONVERGE software, a diesel engine model of the engine was produced. To better obtain the characteristic results of the engine, this was coupled with an improved chemical kinetics mechanism. Then, the results of this model were verified experimentally. Additionally, the effects of four different EGR rates on the combustion, performance, and emissions of a dual-fuel diesel engine were investigated by the verified model under different (50 %, 75 %, and 100 %) load conditions. Lastly, the brake specific fuel consumption, NOx emission, and HC emission were optimized by the response surface methodology (RSM). The results show that the pressure, temperature, and NOx emission in the engine's cylinder can all be reduced by raising the EGR at three different loads. Besides, the optimization results show that the engine achieves the best operating conditions at 100 % load, hydrogen fraction of 6.92 %, and EGR rate of 7.68 %.

Design and Fabrication of Annular-Array Ultrasound Transducer Based (K, Na) NbO3 Lead-Free 1-3 Piezoelectric Composite

This article reports the design, fabrication, and performance of an annular-array ultrasound transducer using (K, Na)NbO3 (KNN)-based lead-free 1-3 piezoelectric composite. The 1-3 piezoelectric composite based on lead-free 0.965(K0.45Na0.55)(Nb0.96Sb0.04)O3-0.035 Bi0.5Na0.5Zr0.85Hf0.15O3 (KNNS-BNZH) was first prepared with the dice-and-fill method. Different from previous reported studies, by patterning annular electrodes on this kind of 1-3 composite, a five-element annular-array transducer in diameter of 6 mm was designed and successfully fabricated and its working center frequency was increased from 5 MHz to around 15 MHz. Meanwhile, a -6 dB bandwidth of 50% was achieved for each annular-array element via a pulse-echo response measurement. Moreover, the obtained annular-array transducer exhibits low crosstalk (<-40 dB) and a high electromechanical coupling coefficient of around 0.7. The application of ultrasonic imaging was further demonstrated to show its excellent performance. Both theoretical analysis and experimental results show that the obtained annular-array transducer presented in this work has a competitive capability for ultrasonic application.

Effects of High-Pressure Homogenization Treatment on the Development of Antioxidant Zanthoxylum bungeanum Leaf Powder Films for Preservation of Fresh-Cut Apple

This study determined that Zanthoxylum bungeanum leaves (ZBLs) are rich in functional components such as cellulose, protein, flavone, and polyphenols. Therefore, they were used as the main raw material, with sodium alginate as a thickener and glycerol as a plasticizer, to investigate the preparation of active films from ZBL powder through high-pressure homogenization (HPH). The physical, optical, mechanical, and antioxidant properties of the films were evaluated, and their application in preserving fresh-cut apples was examined. The results showed that the optimal concentration of ZBL powder was 1.5% under a 30 MPa HPH treatment. The resulting HPH-treated films exhibited a denser microstructure and improved water vapor barrier properties and mechanical strength. Compared to the films without HPH treatment, the tensile strength increased from 4.61 MPa to 12.13 MPa, the elongation at break increased from 21.25% to 42.86%, the water vapor permeability decreased from 9.9 × 10-9 g/m·s·Pa to 8.0 × 10-9 g/m·s·Pa, and the transparency increased from 25.36% to 38.5%. Compared to the control group, the fresh-cut apples packaged with the HPH-treated ZBL active films exhibited effective preservation of apple quality during a five-day period at 4 °C and 70% humidity, showing better preservation effects than the other groups. In conclusion, the use of HPH treatment in developing novel biopolymer active films from ZBL powders with enhanced properties holds potential for various applications.

Nutrient condition modulates the antibiotic tolerance of Pseudomonas aeruginosa

The variation in nutrient content across diverse environments has a significant impact on the survival and metabolism of microorganisms. In this study, we examined the influence of nutrients on the antibiotic tolerance of the PAO1 strain of Pseudomonas aeruginosa. Our findings indicate that under nutrient-rich conditions, this strain exhibited relatively high tolerance to ceftazidime, chloramphenicol, and tetracycline, but not aminoglycosides and fluoroquinolones. Transcriptome analysis revealed that genes associated with antibiotic tolerance were expressed more efficiently in nutrient-rich media, including ribosomal protein genes and multidrug efflux pump genes, which conferred higher tetracycline tolerance to the strain. Furthermore, the genes responsible for translation, biosynthesis, and oxidative phosphorylation were suppressed when nutrients were limited, resulting in decreased metabolic activity and lower sensitivity to ciprofloxacin. Artificial interference with ATP synthesis utilizing arsenate confirmed that the curtailment of energy provision bolstered the observed tolerance to ciprofloxacin. In general, our results indicate that this strain of P. aeruginosa tends to activate its intrinsic resistance mechanisms in nutrient-rich environments, thereby enhancing resistance to certain antibiotics. Conversely, in nutrient-limited environments, the strain is more likely to enter a dormant state, which enables it to tolerate antibiotics to which it would otherwise be sensitive. These findings further suggest that antibiotics released in environments with varying eutrophication levels may have divergent effects on the development of bacterial antibiotic resistance.

The Measurement of Atmospheric Black Carbon: A Review

Black Carbon (BC), the second-largest contributor to global warming, has detrimental effects on human health and the environment. However, the accurate quantification of BC poses a significant challenge, impeding the comprehensive assessment of its impacts. Therefore, this paper aims to critically review three quantitative methods for measuring BC: Thermal Optical Analysis (TOA), the Optical Method, and Laser-Induced Incandescence (LII). The determination principles, available commercial instruments, sources of deviation, and correction approaches associated with these techniques are systematically discussed. By synthesizing and comparing the quantitative results reported in previous studies, this paper aims to elucidate the underlying relationships and fundamental disparities among Elemental Carbon (EC), Equivalent Black Carbon (eBC), and Refractory Black Carbon (rBC). Finally, based on the current advancements in BC quantification, recommendations are proposed to guide future research directions.

Structural characterization of cell-wall polysaccharides purified from chayote (Sechium edule) fruit

Chayote (Sechium edule), an underutilized cucurbit vegetable crop, has gained attention as it exhibits health-promoting properties. However, the primary structure of chayote cell-wall polysaccharides has not been comprehensively studied. In this study, two cell-wall polysaccharides, CP-1 (41.1 KDa) and CP-2 (15.6 KDa), were extracted from chayote, and the structural analysis of CP-1 and CP-2 was carried out by monosaccharide composition analysis, Fourier transform infrared spectroscopy (FTIR), methylation analysis, and nuclear magnetic resonance spectroscopy (NMR). The results demonstrated that CP-1 was a galactan, and CP-2 was an anionic heteropolysaccharide composed of galacturonic acid, galactose, arabinose, rhamnose, glucose, glucuronic acid, mannose, and xylose in the molar ratio of 31.2:26.3:24.9:7.4:6.5:1.9:1.3:0.5. CP-2 has a backbone of → 4)-β-d-Galp-(1 → 3,6)-β-d-Galp-(1 → 3)-β-d-Galp-(1 → 4)-α-d-GalpA-(1→, with branches at O-6 of → 3,6)-β-d-Galp-(1→, consisting of α-l-Araf-(1 → 5)-α-l-Araf-(1 → 4)-β-d-Glcp-(1 →. Analysis of the structural and physicochemical properties confirmed the excellent application characteristics of CP-1 and CP-2. Hence, cell-wall polysaccharides of chayote could be used as new polysaccharides materials.

Study on Porosity of Thermal-Sprayed Commercially Pure Aluminum Coating

Porosity is closely related to the corrosion and wear properties of a coating processed by thermal-spraying technology, and the quantitative characterization of porosity is a crucial part of the research on coating structures. The current image analysis method often uses the mechanical polishing method recommended by ISO to measure a coating porosity. This method has been proved to be an effective method for the characterization of oxide coatings. However, due to the significant differences in the physical and chemical properties between aluminum and oxides, this method may not be suitable for aluminum coatings, and a more appropriate approach needs to be explored. In this paper, the effects of three polishing technologies (mechanical polishing, argon-ion-beam polishing, and electrolytic polishing) on the porosity measurement of pure aluminum coatings were compared and studied. The research results showed that the commonly used mechanical polishing method and more advanced argon-ion-beam polishing method could not completely reveal the pore structure because SiC particles would be embedded in the pure aluminum coatings during mechanical polishing, filling large pores. Although electrolytic polishing technology had advantages in revealing the macroporous structure, it would introduce a microporous structure and oxides, which would affect the measurement of the coating porosity. The composite polishing technology (electrolytic polishing + argon-ion-beam polishing) could perfectly reveal the pore structure in the pure-aluminum coating, and the porosity of arc-sprayed aluminum coating was 9.9%, which was close to the macroscopic true value measured using the weighing method of 10.2%.