Salmonella prevalence in raw cocoa beans and a microbiological risk assessment to evaluate the impact of cocoa liquor processing on the reduction of Salmonella.

Salmonella in raw cocoa beans (n= 870) from main sourcing areas over nine months was analyzed. It was detected in 71 (ca. 8.2%) samples, with a contamination level of 0.3-46 MPN/g except for one sample (4.1×104 CFU/g). Using prevalence and concentration data as input, the impact of thermal treatment in cocoa processing on the risk estimate of acquiring salmonellosis by a random Belgian chocolate consumer was calculated by a quantitative microbiological risk assessment (QMRA) approach. A modular process risk model from raw cocoa beans to cocoa liquor up to a hypothetical final product (70-90% dark chocolate tablet), was set up to understand changes of Salmonella concentrations following the production process. Different thermal treatments during bean or nib steam, nib roasting or liquor sterilization (achieving a 0-6 log reduction of Salmonella) were simulated. Based on the generic FAO/WHO Salmonella dose-response model and the chocolate consumption data in Belgium, salmonellosis risk per serving and cases per year at population level were estimated. When a 5 log reduction of Salmonella was achieved, the estimated mean risk per serving was 3.35×10-8 (95% CI: 3.27×10-10-1.59×10-7), and estimated salmonellosis cases per year (11.7 million population) was 88 (95% CI: <1-418). The estimated mean risk per serving was 3.35×10-9 (95% CI: 3.27×10-11-1.59×10-8), and the estimated salmonellosis cases per year was 9 (95% CI: <1-42), for a 6 log reduction. The current QMRA model solely considered Salmonella reduction in a single-step thermal treatment in the cocoa process. Inactivation obtained during other process steps (e.g. grinding) might occur but was not considered. As the purpose was to use QMRA as a tool to evaluate the log reduction in the cocoa processing, no post-contamination from the processing environment and ingredients was included. A minimum of 5 log reduction of Salmonella in the single-step thermal treatment of cocoa process, was considered to be adequate.

Collagen-based hydrogels induce stem cell chondrogenesis and hyaline cartilage regeneration: An in vivo study.

Injectable, self-crosslinking collagen-based hydrogels are beneficial for chondrocytes to secrete matrix, positioning them as promising candidates for cartilage tissue engineering. However, previous studies lacked insight into the ability of cell-free collagen-based hydrogels to achieve in situ hyaline cartilage regeneration. Therefore, this study aimed to evaluate the potential of collagen-based hydrogels (Col and ColHA) to induce chondrogenic differentiation of stem cells and in situ hyaline cartilage regeneration. Both Col and ColHA hydrogels self-crosslinked in situ and exhibited similar physical properties. In vitro experiments showed they supported the survival, adhesion, spreading, and proliferation of bone marrow stem cells (BMSCs). Moreover, both hydrogels induced ectopic differentiation of BMSCs into chondrocytes when implanted subcutaneously into the back of nude mice. ColHA hydrogel notably enhanced type II collagen secretion. The results of repairing cartilage defects in situ revealed both hydrogels facilitated hyaline cartilage regeneration and maintained cartilage phenotype without exogenous BMSCs. Hydrogels encapsulating BMSCs expedited cartilage repair, and ColHA/BMSC constructs showed better mechanical properties, suggesting their potential for cartilage repair applications. This study implies that collagen-based hydrogels are good candidates for hyaline cartilage regeneration.

Substantial increase in perfluorocarbons CF4 (PFC-14) and C2F6 (PFC-116) emissions in China.

The perfluorocarbons tetrafluoromethane (CF4, PFC-14) and hexafluoroethane (C2F6, PFC-116) are potent greenhouse gases with near-permanent atmospheric lifetimes relative to human timescales and global warming potentials thousands of times that of CO2. Using long-term atmospheric observations from a Chinese network and an inverse modeling approach (top-down method), we determined that CF4 emissions in China increased from 4.7 (4.2-5.0, 68% uncertainty interval) Gg y-1 in 2012 to 8.3 (7.7-8.9) Gg y-1 in 2021, and C2F6 emissions in China increased from 0.74 (0.66-0.80) Gg y-1 in 2011 to 1.32 (1.24-1.40) Gg y-1 in 2021, both increasing by approximately 78%. Combined emissions of CF4 and C2F6 in China reached 78 Mt CO2-eq in 2021. The absolute increase in emissions of each substance in China between 2011-2012 and 2017-2020 was similar to (for CF4), or greater than (for C2F6), the respective absolute increase in global emissions over the same period. Substantial CF4 and C2F6 emissions were identified in the less-populated western regions of China, probably due to emissions from the expanding aluminum industry in these resource-intensive regions. It is likely that the aluminum industry dominates CF4 emissions in China, while the aluminum and semiconductor industries both contribute to C2F6 emissions. Based on atmospheric observations, this study validates the emission magnitudes reported in national bottom-up inventories and provides insights into detailed spatial distributions and emission sources beyond what is reported in national bottom-up inventories.

Novel mechanistic insights into Cr(VI) and Cr(III) induced discrepancies of cellular toxicity and oxidative injury events in Eisenia fetida.

Chromium (Cr) poses a high ecological risk, however the toxic mechanisms of Cr in different valence states to soil organisms at cellular and molecular levels are not exactly. In this study, the Eisenia fetida coelomocytes and Cu/Zn-superoxide dismutase (Cu/Zn-SOD) were chosen as the target subjects to investigate the effects and mechanisms of cellular toxicity induced by Cr(VI) and Cr(III). Results indicated that Cr(VI) and Cr(III) significantly reduced the coelomocytes viability. The level of reactive oxygen species (ROS) was markedly increased after Cr(VI) exposure, which finally reduced antioxidant defense abilities, and induced lipid peroxidation and cellular membrane damage in earthworm coelomocytes. However, Cr(III) induced lower levels of oxidative stress and cellular damage with respect to Cr(VI). From a molecular perspective, the binding of both Cr(VI) and Cr(III) with Cu/Zn-SOD resulted in protein backbone loosening and reduced ß-Sheet content. The Cu/Zn-SOD showed fluorescence enhancement with Cr(III), whereas Cr(VI) had no obvious effect. The activity of Cu/Zn-SOD continued to decrease with the exposure of Cr. Molecular docking indicated that Cr(III) interacted more readily with the active center of Cu/Zn-SOD. Our results illustrate that oxidative stress induced by Cr(VI) and Cr(III) plays an important role in the cytotoxic differences of Eisenia fetida coelomocytes and the binding of Cr with Cu/Zn-SOD can also affect the normal structures and functions of antioxidant defense-associated protein.

Biofilm-forming Ability of Bacillus thuringiensis Strains from Biopesticides on Polystyrene and their Attachment on Spinach.

Bacillus thuringiensis-based commercial products as a biopesticide have been used for more than 60 years in agriculture. However, as one of the species in B. cereus group, B. thuringiensis has been considered as an emerging hazard with the potential to cause food toxico-infections. The present study aimed to evaluate the biofilm-forming ability of B. thuringiensis biopesticide strains and their attachment on spinach, compared to foodborne B. cereus strains. Biofilm formations of tested strains were found to be strain-specific and affected by the nutrient conditions more than the incubation time. Nutrient starvation conditions generally reduced the biofilm formation of tested B. thuringiensis and B. cereus strains, particularly B. thuringiensis ABTS-1857 strain was found as the nonbiofilm former in starvation conditions. It is worth mentioning that B. thuringiensis SA-11 strain showed stronger biofilm-forming ability with more air-liquid interface biofilm than the other two B. thuringiensis biopesticide strains, but no such higher attachment of B. thuringiensis SA-11 to spinach was observed. These results indicate that B. thuringiensis SA-11 strain can enter the food processing lines by the attachment on spinach leaves, and it has the potential to form biofilms throughout the processing lines or the production environment when sufficient nutrients are available. However, more biofilm tests of B. thuringiensis biopesticide strains in the vegetable production chain should be performed. The dry formulation of commercial B. thuringiensis biopesticides enhanced their adhesion on spinach leaves, whereas the strength of adhesion was not improved by the formulation. In addition, 1-2 log reductions of spores after the intensive washing of spinach leaves in the lab were detected. However, the log reduction due to the actual washing done by the food processing companies in large-volume washing baths or by consumers at home would be limited and less than this lab simulation.

Rising Perfluorocyclobutane (PFC-318, c-C4F8) Emissions in China from 2011 to 2020 Inferred from Atmospheric Observations.

Global atmospheric emissions of perfluorocyclobutane (c-C4F8, PFC-318), a potent greenhouse gas, have increased rapidly in recent years. Combining atmospheric observations made at nine Chinese sites with a Lagrangian dispersion model-based Bayesian inversion technique, we show that PFC-318 emissions in China grew by approximately 70% from 2011 to 2020, rising from 0.65 (0.54-0.72) Gg year-1 in 2011 to 1.12 (1.05-1.19) Gg year-1 in 2020. The PFC-318 emission increase from China played a substantial role in the overall increase in global emissions during the study period, contributing 58% to the global total emission increase. This growth predominantly originated in eastern China. The regions with high emissions of PFC-318 in China overlap with areas densely populated with polytetrafluoroethylene (PTFE) factories, implying that fluoropolymer factories are important sources of PFC-318 emissions in China. Our investigation reveals an emission factor of approximately 3.02 g of byproduct PFC-318 emissions per kg of hydrochlorofluorocarbon-22 (HCFC-22) feedstock use in the production of tetrafluoroethylene (TFE) (for PTFE production) and hexafluoropropylene (HFP) if we assume all HCFC-22 produced for feedstock uses in China are pyrolyzed to produce PTFE and HFP. Further facility-level sampling and analysis are needed for a more precise evaluation of emissions from these factories.

Emerging N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) and 6PPD quinone in paired human plasma and urine from Tianjin, China: Preliminary assessment with demographic factors.

With increasing concerns about N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) and 6PPD-quinone (6PPD-Q), relevant environmental investigations and toxicological research have sprung up in recent years. However, limited information could be found for human body burden assessment. This work collected and analyzed 200 samples consisting of paired urine and plasma samples from participants (50 male and 50 female) in Tianjin, China. Low detection frequencies (DF, <15 %) were found except for urinary 6PPD-Q (86 %), which suggested the poor residue tendency of 6PPD and 6PPD-Q in blood. The low DFs also lead to no substantial association between two chemicals. Data analysis based on urinary 6PPD-Q showed a significant difference between males and females (p < 0.05). No significant correlation was found for other demographic factors (Body Mass Index (BMI), age, drinking, and smoking). The mean values of daily excretion (ng/kg bw/day) calculated using urinary 6PPD-Q for females and males were 7.381 ng/kg bw/day (female) and 3.360 ng/kg bw/day (male), and apparently female suffered higher daily exposure. Further analysis with daily excretion and ALT (alanine aminotransferase)/TSH (thyroid stimulating hormone)/ blood cell analysis indicators found a potential correlation with 6PPD-Q daily excretion and liver/immune functions. Considering this preliminary assessment, systematic research targeting the potential organs at relevant concentrations is required.

The size-dependent effects of nanoplastics in mouse primary hepatocytes from cells to molecules.

Nanoplastics (NPs) are easily ingested by organisms and their major accumulation organ was determined to be liver. To date, the size-dependent cytotoxicity of NPs on mammalian hepatocytes remains unclear. This study utilized mouse primary hepatocytes and catalase (CAT) as specific receptors to investigate the toxicity of NPs from cells to molecules, focusing on size-dependent effects. Results showed that the larger the particle size of NP at low doses (≤50 mg/L), the most pronounced inhibitory effect on hepatocyte viability. 20 nm NPs significantly inhibit cell viability only at high doses (100 mg/L). Larger NP particles (500 nm and 1000 nm) resulted in a massive release of lactate dehydrogenase (LDH) from the cell (cell membrane damage). Reactive oxygen species (ROS), superoxide dismutase (SOD) and CAT tests suggest that NPs disturbed the cellular antioxidant system. 20 nm NPs show great strength in oxidizing lipids and disrupting mitochondrial function compared to NPs of other particle sizes. The degree of inhibition of CAT activity by different sized NPs was coherent at the cellular and molecular levels, and NP-500 had the most impact. This suggests that the structure and microenvironment of the polypeptide chain in the vicinity of the CAT active site is more susceptible to proximity and alteration by NP-500. In addition, the smaller NPs are capable of inducing relaxation of CAT backbone, disruption of H-bonding and reduction of α-helix content, whereas the larger NPs cause contraction of CAT backbone and increase in α-helix content. All NPs induce CAT fluorescence sensitization and make the chromophore microenvironment hydrophobic. This study provides new insights for NP risk assessment and applications.

Enhanced sinks of polystyrene nanoplastics (PSNPs) in marine sediment compared to freshwater sediment: Influencing factors and mechanisms.

The difference in the transport behaviors of nanoplastics consistently assistant with their toxicities to benthic and other aquatic organisms is still unclear between freshwater and marine sediments. Here, the mobilities of polystyrene nanoplastics (PSNPs) and key environmental factors including salinity and humic acid (HA) were systematically studied. In the sand column experiments, both tested PSNPs in the freshwater system (100 nm NPs (100NPs): 90.15 %; 500 nm NPs (500NPs): 54.22 %) presented much higher penetration ratio than in the marine system (100NPs: 8.09 %; 500NPs: 19.04 %). The addition of marine sediment with a smaller median grain diameter caused a much more apparent decline in NPs mobility (100NPs: from 8.09 % to 1.85 %; 500NPs: from 19.04 % to 3.51 %) than that containing freshwater sediment (100NPs: from 90.15 % to 83.56 %; 500NPs: from 54.22 % to 41.63 %). Interestingly, adding HA obviously led to decreased and slightly increased mobilities for NPs in freshwater systems, but dramatically improved performance for NPs in marine systems. Electrostatic and steric repulsions, corresponding to alteration of zeta potential and hydrodynamic diameter of NPs and sands, as well as minerals owing to adsorption of dissolved organic matter (DOM) and aggregations from varied salinity, are responsible for the mobility difference.

Sustained growth of sulfur hexafluoride emissions in China inferred from atmospheric observations.

Sulfur hexafluoride (SF6) is a potent greenhouse gas. Here we use long-term atmospheric observations to determine SF6 emissions from China between 2011 and 2021, which are used to evaluate the Chinese national SF6 emission inventory and to better understand the global SF6 budget. SF6 emissions in China substantially increased from 2.6 (2.3-2.7, 68% uncertainty) Gg yr-1 in 2011 to 5.1 (4.8-5.4) Gg yr-1 in 2021. The increase from China is larger than the global total emissions rise, implying that it has offset falling emissions from other countries. Emissions in the less-populated western regions of China, which have potentially not been well quantified in previous measurement-based estimates, contribute significantly to the national SF6 emissions, likely due to substantial power generation and transmission in that area. The CO2-eq emissions of SF6 in China in 2021 were 125 (117-132) million tonnes (Mt), comparable to the national total CO2 emissions of several countries such as the Netherlands or Nigeria. The increasing SF6 emissions offset some of the CO2 reductions achieved through transitioning to renewable energy in the power industry, and might hinder progress towards achieving China's goal of carbon neutrality by 2060 if no concrete control measures are implemented.

The weakened physiological functions of human serum albumin in presence of polystyrene nanoplastics.

Due to the widespread presence of nanoplastics (NPs) in daily essentials and drinking water, the potential adverse effects of NPs on human health have become a global concern. Human serum albumin (HSA), the most abundant and multi-functional protein in plasma, has been chosen to understand the biological effects of NPs after entering the blood. The esterase activity and the transport of bisphenol A in the presence of polystyrene nanoplastics (PSNPs) under physiological conditions (pH 4.0 and 7.4) have been investigated to evaluate the possible biological effects. The interactions between PSNPs and HSA have also been systematically studied by multispectral methods and dynamic light scattering techniques. The esterase activity of HSA presented a decreased trend with increasing PSNPs; conversely, higher permeabilities are accompanied by higher amounts of PSNPs. Compared with the unchanged hydrodynamic diameter and weaker interactions at pH 7.4, stronger binding between HSA and PSNPs at pH 4.0 led to a significant increase in the particle size of the PSNPs-HSA complex. The quenching mechanism belonged to the static quenching type. The electrostatic force is proposed to be the dominant factor for PSNPs binding to HSA. The work provides some information about the toxicity of NPs when exposed to humans.

Components and physical properties of hydrogels modulate inflammatory response and cartilage repair.

Collagen and hyaluronic acid are commonly applied in cartilage tissue engineering, yet there has been limited investigation into their inflammatory response, a crucial factor in articular cartilage repair. This study aimed to evaluate the impact of components and physical properties of hydrogels on inflammatory response and cartilage repair. Three kinds of hydrogels with comparable storage moduli at low frequencies were designed and fabricated, namely, methacrylic anhydride-modified hyaluronic acid hydrogel (HAMA), methacrylic anhydride-modified type I collagen hydrogel (CMA) and unmodified type I collagen hydrogel (Col). HAMA hydrogel was unfavorable for adhesion and spreading of BMSCs. Furthermore, HAMA hydrogel stimulated rapid migration and pro-inflammatory M1 polarization of macrophages, leading to persistent and intense inflammation, which was unfavorable for cartilage repair. CMA and Col hydrogels possessed the same component and facilitated the adhesion, spreading and proliferation of BMSCs. Compared with CMA hydrogel, Col hydrogel induced rapid migration and moderate M1 polarization of macrophages at the early stage of injury, which was mainly influenced by its fast dissolution rate, small pore size fiber network structure and rapid stress relaxation. In addition, the phenotype of macrophages timely transformed into anti-inflammatory M2 due to the properties of the collagen component, which shortened the duration of inflammation and enhanced cartilage repair. The results indicated that moderate macrophage activation adjusted by hydrogel components and physical properties was critical in modulating inflammation and cartilage regeneration.

Role of TFEB in regulation of the podocyte actin cytoskeleton.

Podocyte injury is linked to the pathogenesis and progression of renal disease. The Transcription Factor EB (TFEB), a master regulator of the autophagy and lysosomal pathways, has been found to exert cell- and tissue-specific biological function. To explore TFEB function and underlying mechanisms in podocytes, a total of 4645 differentially expressed genes (DEGs) were detected in TFEB-knockdown mouse podocytes by transcriptome sequencing. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and Ingenuity Pathway Analysis showed that, apart from the enrichment in autophagy and lysosomal pathways, DEGs were enriched in cytoskeleton structure (Actin Cytoskeleton, Focal Adhesion, and Adherens Junction), as well as cytoskeleton regulatory molecular signaling (Hippo and Rho GTPase Signaling). In vitro, TFEB knockdown resulted in podocyte cytoskeletal rearrangement, which was disorganized with cortical distribution of actin filaments. Further, TFEB knockdown decreased mRNA and protein levels of Synaptopodin and led to the rearrangement of Synaptopodin. Inhibition of TFEB decreased mRNA levels for proteins involved in actin cytoskeleton dynamics. Moreover, apoptosis was increased by TFEB knockdown in podocyte. In summary, this study initiated a comprehensive analysis of the role of TFEB in podocyte function and the potential underlying mechanisms, and identified a novel role for TFEB in regulation of the podocyte actin cytoskeleton.

Iron oxide nanozymes stabilize stannous fluoride for targeted biofilm killing and synergistic oral disease prevention.

Dental caries is the most common human disease caused by oral biofilms despite the widespread use of fluoride as the primary anticaries agent. Recently, an FDA-approved iron oxide nanoparticle (ferumoxytol, Fer) has shown to kill and degrade caries-causing biofilms through catalytic activation of hydrogen peroxide. However, Fer cannot interfere with enamel acid demineralization. Here, we show notable synergy when Fer is combined with stannous fluoride (SnF2), markedly inhibiting both biofilm accumulation and enamel damage more effectively than either alone. Unexpectedly, we discover that the stability of SnF2 is enhanced when mixed with Fer in aqueous solutions while increasing catalytic activity of Fer without any additives. Notably, Fer in combination with SnF2 is exceptionally effective in controlling dental caries in vivo, even at four times lower concentrations, without adverse effects on host tissues or oral microbiome. Our results reveal a potent therapeutic synergism using approved agents while providing facile SnF2 stabilization, to prevent a widespread oral disease with reduced fluoride exposure.

UV-C and wet heat resistance of Bacillus thuringiensis biopesticide endospores compared to foodborne Bacillus cereus endospores.

Bacillus endospores (spores) are generally resistant to environmental and food processing-related stress including thermal and non-thermal processing in the food industry, such as pasteurization, and UV-C inactivation. Bacillus thuringiensis insecticidal crystals and spores as the active substances in commercial biopesticides can also be introduced to vegetable foods and their food processing environment due to pre-harvest treatment of edible crops. The resistance of B. thuringiensis biopesticide spores in comparison to the genetically closely related foodborne B. cereus against heat and UV-C treatment is investigated in this study. The results show that B. thuringiensis biopesticide spores with the commercial granulated product formulation are better protected and as such more resistant to both wet heat (D values at 90 °C: 50.1-79.5 min) and UV-C treatment (D values at 0.6 mW/cm2: 7.5-8.9 min) than the pure spore suspension. The enhanced UV-C resistance properties of B. thuringiensis-formulated spores also indicate that the B. thuringiensis spores in powder or granule formulation applied in the field might not be effectively inactivated by solar radiation (UV-A and UV-B) in a short period. Furthermore, the spores of one emetic B. cereus toxin-producing strain (LFMFP 254; a Belgian outbreak strain) were found more resistant to the wet heat at 90 °C (D90-value = 71.2 min) than other tested pure spore suspensions, although the spores of B. cereus 254 did not show different behavior against UV-C treatment. This result suggests that UV-C treatment can be applied as an effective inactivation method against B. cereus 254 spores.

Development of a solubility parameter calculation-based method as a complementary tool to traditional techniques for indoor dust microplastic determination and risk assessment.

Herein, a method based on solubility parameter calculation was first used to analyze microplastics in indoor dust. The limit of quantification (LOQ) reached 0.2 mg/g, and the result of reference material SRM 2585 (n = 3) was 14.8 mg/g ± 1.8 %, suggesting satisfying sensitivity and precision. Recoveries of spiking experiments were > 80 % with no obvious matrix interferences observed, except ethylene propylene diene monomer (EPDM) MPs. Further, 69 indoor dust samples were analyzed to verify the method and to assess exposure scenarios for graduate students in Tianjin, China. EPDM was identified in an indoor environment for the first time as the second most widely detected type after PET in this work. The mass-based result is complementary to the outcomes from thermogravimetric analysis-gas chromatography-mass spectrometry and laser direct infrared imaging. Significant correlations were found between total organic carbon (TOC), microplastics, and BDE-209 concentrations, indicating microplastics important contaminant vectors in indoor dust. Dormitory stays and PET contributed the most to health risks among the three exposure scenarios and detected four polymers, respectively. This work provides an approach with the potential for the standardized determination of microplastics in complex environmental matrices and reveals exposure characteristics of indoor dust microplastics.

Binding divergence of polystyrene nanoparticles with serum albumin caused by surface functionalization.

Using a combination of spectroscopy, we devised an integrated structural strategy to comprehensively profile the molecular details of the impact of differently functionalized (plain, aminated, and carboxylated) polystyrene nanoparticles (PSNPs) on human serum albumin (HSA). The binding isotherms obtained from fluorescence and UV-vis absorption measurements demonstrate that surface functionalization can distinguish the interaction of PSNPs with HSA. Three-dimensional fluorescence and circular dichroism analysis of the effect of interaction with PSNPs on the native conformation and secondary structures of the protein reveals a diminution in the skeleton structure of HSA induced by the PSNPs. In accordance with this, it is discovered that the esterase activity of protein-PSNPs aggregates is diminished compared to that of the native protein. The carboxylated PSNPs exhibited the strongest protein binding and perturbation effects compared to other particles. Plain PSNPs exhibited significant hydrophobic interaction properties, as evidenced by spectral blue shifts and a diminished Stokes shift in the three-dimensional fluorescence assay. Our results exclusively highlight that the hydrophobic and surface charge characteristics of PSNPs govern the extent of interaction with the protein, which is beneficial to understanding microplastic toxicology.

Interaction of polystyrene nanoplastics and hemoglobin is determined by both particle curvature and available surface area.

Understanding nanoplastic (NP, or nanoparticle in general) toxicity requires establishing the causal relationships between the physical properties of the nanoparticles and their biological impact. We use spectroscopic, zeta-potential, and dynamic light scattering (DLS) techniques to investigate the formation, structure, and catalytic properties of hemoglobin corona complexes with polystyrene NPs (0-10 mg/mL) of various diameters (20, 50, 100, 500, and 5000 nm). Resonance light scattering, zeta-potential analysis, and DLS demonstrated that hemoglobin corona complexes formed different forms of aggregates with NPs in terms of diameter. Medium-sized (100 nm) NPs induced the most significant conformational alterations in the protein corona compared to smaller and larger ones, which was revealed by spectroscopic assays. However, the catalase-like activity of hemoglobin was promoted in the presence of 100 nm NPs by as high as 35.2 %. NP curvature and surface area are antagonistic factors that govern the conformation of proteins together. This also suggests that 100 nm NPs are more likely to disrupt protein-dependent physiological processes at a given mass concentration than small or large NPs.

Improve the performance of CT-based pneumonia classification via source data reweighting.

Pneumonia is a life-threatening disease. Computer tomography (CT) imaging is broadly used for diagnosing pneumonia. To assist radiologists in accurately and efficiently detecting pneumonia from CT scans, many deep learning methods have been developed. These methods require large amounts of annotated CT scans, which are difficult to obtain due to privacy concerns and high annotation costs. To address this problem, we develop a three-level optimization based method which leverages CT data from a source domain to mitigate the lack of labeled CT scans in a target domain. Our method automatically identifies and downweights low-quality source CT data examples which are noisy or have large domain discrepancy with target data, by minimizing the validation loss of a target model trained on reweighted source data. On a target dataset with 2218 CT scans and a source dataset with 349 CT images, our method achieves an F1 score of 91.8% in detecting pneumonia and an F1 score of 92.4% in detecting other types of pneumonia, which are significantly better than those achieved by state-of-the-art baseline methods.

PM2.5 Increases Systemic Inflammatory Cells and Associated Disease Risks by Inducing NRF2-Dependent Myeloid-Biased Hematopoiesis in Adult Male Mice.

Although PM2.5 (fine particles with aerodynamic diameter <2.5 µm) exposure shows the potential to impact normal hematopoiesis, the detailed alterations in systemic hematopoiesis and the underlying mechanisms remain unclear. For hematopoiesis under steady-state or stress conditions, nuclear factor erythroid 2-related factor 2 (NRF2) is essential for regulating hematopoietic processes to maintain blood homeostasis. Herein, we characterized changes in the populations of hematopoietic stem progenitor cells and committed hematopoietic progenitors in the lungs and bone marrow (BM) of wild-type and Nrf2-/- C57BL/6J male mice. PM2.5-induced NRF2-dependent biased hematopoiesis toward myeloid lineage in the lungs and BM generates excessive numbers of various inflammatory immune cells, including neutrophils, monocytes, and platelets. The increased population of these immune cells in the lungs, BM, and peripheral blood has been associated with observed pulmonary fibrosis and high disease risks in an NRF2-dependent manner. Therefore, although NRF2 is a protective factor against stressors, upon PM2.5 exposure, NRF2 is involved in stress myelopoiesis and enhanced PM2.5 toxicity in pulmonary injury, even leading to systemic inflammation.