Hepatitis B Virus DNA-Level Change is Associated With Tumor Recurrence in Patients With Resected Hepatitis B Virus Hepatocellular Carcinoma.

INTRODUCTION: To investigate the significance of perioperative hepatitis B virus (HBV) DNA changes for predicting recurrence in patients with HBV-related hepatocellular carcinoma (HCC) undergoing liver resection (LR). METHODS: From 2013 to 2020, 241 patients with HBV-related HCC who underwent LR in five Hallym university-affiliated hospitals were enrolled. The serum HBV DNA level, together with other clinicopathological variables, was analyzed for association with HCC recurrence. RESULTS: Preoperatively, 99 patients had undetectable HBV DNA and 142 had detectable viral levels. Of those with detectable viral levels, 72 rapidly progressed to undetectable levels within 3 mo after LR (Rapid group), and 70 showed persistently detectable levels (Nonrapid group). The Rapid group had a better recurrence-free survival (RFS) rate than the Nonrapid group (1-y, 3-y RFS = 75.4%, 57.3%, versus 54.7%, 39.9%, respectively, P = 0.012). In the subgroup analysis, the Rapid group had a better RFS rate in early stages (1-y, 3-y RFS = 82.6%, 68.5%, versus 62.8%, 45.8%, respectively, P = 0.005); however, the RFS rates between the two groups were comparable in the advanced stage (1-y, 3-y RFS = 61.1%, 16.7% versus 45.5%, 22.7%, respectively, P = 0.994). Among the 142 patients with preoperatively detectable HBV DNA, persistently detectable HBV DNA within 3 mo postoperatively (hazard ratio [HR] = 1.7, P = 0.022), large tumor size (HR = 2.7, P < 0.001), multiple tumors (HR = 3.2, P < 0.001), and microvascular invasion (HR = 1.7, P = 0.028) were independent risk factors for RFS in multivariate analysis. CONCLUSIONS: Rapidly undetectable HBV DNA after LR is associated with a better prognosis for recurrence in patients with HCC. Therefore, appropriate treatment and/or screening may be necessary for patients who do not return to undetectable HBV DNA after LR.

α-Tocopherol-loaded multi-layer nanoemulsion using chitosan, and dextran sulfate: Cellular uptake, antioxidant activity, and in vitro bioaccessibility.

The potential of multi-layer nanoemulsions (NEs) for improving the cellular uptake, antioxidant activity, and in vitro bioaccessibility of α-tocopherol (ToC) was examined. ToC-loaded multi-layer NEs were prepared using lecithin (primary-NEs, P-NEs), chitosan (secondary-NEs, S-NEs), and dextran sulfate (tertiary-NEs, T-NEs) as wall materials. The bioadhesion, cellular permeability, and uptake of the multi-layer NEs were significantly higher than that of the free coumarin 6 (C6). As a result of cellular uptake, the mean fluorescence intensity of T-NEs was the highest among the three types of multi-layer NEs and was 9.8-fold higher than that of free C6. The cellular antioxidant abilities of P-NEs, S-NEs, and T-NEs were 40, 45, and 50 %, respectively. Multi-layer nanoencapsulation sustains free fatty acid release after digestion. Moreover, the bioavailability of T-NEs exhibited a two-fold increase compared with that of the free ToC. These findings indicate that by multi-layer NEs using a layer-by-layer method, the cellular uptake, in vitro bioaccessibility, and antioxidant activity of ToC can be improved. Furthermore, T-NEs using chitosan and dextran sulfate can potentially enhance the cellular uptake, in vitro bioaccessibility, and antioxidant activity of ToC. These findings would facilitate the application of multi-layer NEs for lipophilic bioactive compounds using biopolymers.

Long-Term Outcomes of Liver Transplantation in Hepatocellular Carcinoma with Bile Duct Tumor Thrombus: A Comparison with Portal Vein Tumor Thrombus.

Liver transplantation (LT) in patients with hepatocellular carcinoma (HCC) with bile duct tumor thrombus (BDTT) remains controversial. This study analyzed the recurrence and overall survival rates through long-term results after LT in HCC patients with BDTT and compared the results after LT in HCC patients with portal vein tumor thrombus (PVTT). We performed a retrospective study of 45 patients with PVTT, 16 patients with BDTT, and 11 patients with coexisting PVTT and BDTT among HCC patients who underwent LT at a single center from 1999 to 2020. The HCC recurrence rates were 40.4% at 1 year, 30.3.3% at 2 years, and 27.6% at 3 years in the PVTT group; 66.7%, 53.3%, and 46.7% in the BDTT group; and 22.2%, 22.2%, and 0% in the coexisting group (p = 0.183). Overall patient survival rates were 68.4% at 1 year, 54.3% at 2 years, and 41.7% at 3 years in the PVTT group; 81.3%, 62.5%, and 48.2% in the BDTT group; and 63.6%, 27.3%, and 0% in the coexisting group (p = 0.157). In the multivariate analysis, the pre-transplantation model for tumor recurrence after liver transplantation (MoRAL) score and model for end-stage liver disease (MELD) score were found to be independent risk factors for recurrence and survival in all groups. HCC patients with BDTT showed no difference in recurrence and survival compared with HCC patients with PVTT at the long-term follow-up after LT.

Identification of Risk Groups for and Factors Affecting Metabolic Syndrome in South Korean Single-Person Households Using Latent Class Analysis and Machine Learning Techniques: Secondary Analysis Study.

BACKGROUND: The rapid increase of single-person households in South Korea is leading to an increase in the incidence of metabolic syndrome, which causes cardiovascular and cerebrovascular diseases, due to lifestyle changes. It is necessary to analyze the complex effects of metabolic syndrome risk factors in South Korean single-person households, which differ from one household to another, considering the diversity of single-person households. OBJECTIVE: This study aimed to identify the factors affecting metabolic syndrome in single-person households using machine learning techniques and categorically characterize the risk factors through latent class analysis (LCA). METHODS: This cross-sectional study included 10-year secondary data obtained from the National Health and Nutrition Examination Survey (2009-2018). We selected 1371 participants belonging to single-person households. Data were analyzed using SPSS (version 25.0; IBM Corp), Mplus (version 8.0; Muthen & Muthen), and Python (version 3.0; Plone & Python). We applied 4 machine learning algorithms (logistic regression, decision tree, random forest, and extreme gradient boost) to identify important factors and then applied LCA to categorize the risk groups of metabolic syndromes in single-person households. RESULTS: Through LCA, participants were classified into 4 groups (group 1: intense physical activity in early adulthood, group 2: hypertension among middle-aged female respondents, group 3: smoking and drinking among middle-aged male respondents, and group 4: obesity and abdominal obesity among middle-aged respondents). In addition, age, BMI, obesity, subjective body shape recognition, alcohol consumption, smoking, binge drinking frequency, and job type were investigated as common factors that affect metabolic syndrome in single-person households through machine learning techniques. Group 4 was the most susceptible and at-risk group for metabolic syndrome (odds ratio 17.67, 95% CI 14.5-25.3; P<.001), and obesity and abdominal obesity were the most influential risk factors for metabolic syndrome. CONCLUSIONS: This study identified risk groups and factors affecting metabolic syndrome in single-person households through machine learning techniques and LCA. Through these findings, customized interventions for each generational risk factor for metabolic syndrome can be implemented, leading to the prevention of metabolic syndrome, which causes cardiovascular and cerebrovascular diseases. In conclusion, this study contributes to the prevention of metabolic syndrome in single-person households by providing new insights and priority groups for the development of customized interventions using classification.

Arthroscopic transosseous anchorless rotator cuff repair reduces bone defects related to peri-implant cyst formation: a comparison with conventional suture anchors using propensity score matching.

BACKGROUND: The transosseous anchorless repair (ToR) technique was recently introduced to avoid suture anchor-related problems. While favorable outcomes of the ToR technique have been reported, no previous studies on peri-implant cyst formation with the ToR technique exist. Therefore, this study compared the clinical outcomes and prevalence of peri-implant cyst formation between the ToR technique and the conventional transosseous equivalent technique using suture anchors (SA). METHODS: Cases with arthroscopic rotator cuff repair (ARCR) between 2016 and 2018 treated with the double-row suture bridge technique were retrospectively reviewed. Patients were divided into ToR and SA groups. To compare clinical outcomes, 19 ToR and 57 SA cases without intraoperative implant failure were selected using propensity score matching (PSM). While intraoperative implant failure rate was analyzed before PSM, retear rate, peri-implant cyst formation rate, and functional outcomes were compared after PSM. RESULTS: The intraoperative implant failure rate (ToR, 8% vs. SA, 15.3%) and retear rate (ToR, 5.3% vs. SA, 19.3%) did not differ between the two groups (all P>0.05). However, peri-implant cysts were not observed in the ToR group, while they were observed in 16.7% of the SA group (P=0.008). Postoperative functional outcomes were not significantly different between the two groups (all P>0.05). CONCLUSIONS: The ToR technique produced comparable clinical outcomes to conventional techniques. Considering the prospect of potential additional surgeries, the absence of peri-implant cyst formation might be an advantage of ToR. Furthermore, ToR might reduce the medical costs related to suture anchors and, thereby, could be a useful option for ARCR. Level of evidence: III.

Taste masking and stability improvement of Korean red ginseng (Panax ginseng) by nanoencapsulation using chitosan and gelatin.

In this study, red ginseng extract (RGE)-loaded nanoparticles (NPs) were prepared by ionic gelation between chitosan (CS) and gelatin (Gel), and the physical characteristics of the RGE-loaded CS-Gel NPs (RGE-CS/Gel NPs), including particle size and polydispersity index (PDI), using different ratios of CS and Gel were examined. The particle size and PDI were 398.1 ± 41.3 nm and 0.433 ± 0.033, respectively for the optimal ratio of CS (0.075 mg/mL) and Gel (0.05 mg/mL). In vitro taste masking test and in vivo sensory evaluation using 10 panelists demonstrated that the CS/Gel NPs significantly reduced the bitter taste of RGE. Additionally, the CS/Gel NPs improved the thermal and acid stabilities, which were almost 6 and 8 times higher than those in the free RGE (p < 0.05), respectively. Likewise, our findings revealed that the RGE-CS/Gel NPs effectively maintain their inhibitory function against platelet aggregation (76.30 %) in an acidic environment. Therefore, the CS/Gel NPs can be used as a potential delivery system to mask the bitterness and improve the stability of RGE, which may enhance its application as a more palatable functional food ingredient with high anti-platelet activity.

Korean guidelines for the management of gout.

Gout is the most common form of arthritis, with the prevalence increasing worldwide. The present treatment guidelines provide recommendations for the appropriate treatment of acute gout, management during the inter-critical period, and prevention of chronic complications. The guidelines were developed based on evidence-based medicine and draft recommendations finalized after expert consensus. These guidelines are designed to provide clinicians with clinical evidence to enable efficient treatment of gout.

Korean guidelines for the management of gout.

Gout is the most common form of arthritis, with the prevalence increasing worldwide. The present treatment guidelines provide recommendations for the appropriate treatment of acute gout, management during the inter-critical period, and prevention of chronic complications. The guidelines were developed based on evidence-based medicine and draft recommendations finalized after expert consensus. These guidelines are designed to provide clinicians with clinical evidence to enable efficient treatment of gout.

Linguistic anomalies observed in the Sentence Completion Test in patients with schizophrenia.

BACKGROUND: Schizophrenia is a chronic, debilitating disorder characterised by distorted thinking, perceptions, behaviours, and even language impairments. We investigated the linguistic anomalies in Korean schizophrenia patients compared to non-psychotic psychiatric controls to determine whether the linguistic anomalies in English speakers with schizophrenia were replicated in Korean speakers. METHODS: Thirty-four schizophrenia patients and 70 non-psychotic psychiatric controls were included in this study. The SCT was utilised as the text data for analysis. For linguistic analysis, we evaluated texts regarding semantics and syntax. We separately counted the number of semantic or syntactic errors in the written texts of study participants and compared them between patients and controls. RESULTS: Schizophrenia patients showed significantly more semantic errors (p < .001) and syntactic errors (p < .001) per 1,000 characters than non-psychotic psychiatric controls. Specifically, inappropriate word or syntactic component selection is noticeable in schizophrenia patients. These differences were still significant after adjusting for general intelligence measured by the K-WAIS-IV. CONCLUSION: Schizophrenia patients showed both semantic and syntactic errors in written language. Moreover, these errors seemed to be partly independent of general intelligence. Notably, patients showed a noticeable number of syntactic errors. Further investigation into the language of patients with schizophrenia and schizophrenia-spectrum disorders is required.

Nanoencapsulation of Grapefruit Seed Extract and Cinnamon Oil for Oral Health: Preparation, In Vitro, and Clinical Antimicrobial Activities.

This study aimed to formulate mucoadhesive antimicrobial nanoparticles using natural antimicrobials and biopolymers for oral health and verify their antimicrobial activity in clinical studies. A combination of grapefruit seed extract and cinnamon oil (GCN) and chitosan/carrageenan (CS/CR) were selected as synergistic antimicrobial combinations and mucoadhesive wall materials for nanoparticles, respectively. GCN nanoparticles (NPs; size = 357 nm and polydispersity index = 0.188) prepared by ionic gelation between CS and CR exhibited synergistic antimicrobial activity between grapefruit seed extract and cinnamon oil and significantly higher antimicrobial activity against Streptococcus mutans and sobrinus than free GCN in a time-kill assay. The clinical antibacterial activity of GCN was significantly increased and sustained by nanoencapsulation in the mouth-rinse test and GCN NP-treated drinking yogurt. These results suggest that GCN-loaded CS/CR nanoencapsulation is a promising technique that can inhibit oral bacteria with or without the presence of other food ingredients.

Optimization and release characteristics of catechin-loaded calcium pectinate beads by internal gelation.

The aim of this study was to optimize the composition of catechin-loaded calcium pectinate gel (CPG) beads formed using internal gelation and to evaluate the sustained-release behavior of catechin. The pectin concentration, catechin-to-pectin ratio, and calcium carbonate-to-pectin ratio were optimized for the sustained catechin release (2.89, 28.92, and 32.79%, respectively). The catechin release profiles were analyzed using the simple enzyme kinetic-like semi empirical model newly proposed in this study. The actual release rate was found to be the fastest in the simulated intestinal fluid (SIF), followed by the simulated gastric fluid (SGF) and the pH 4.5 buffer, whereas the thermodynamic equilibrium was achieved fastest in the pH 4.5 buffer, followed by SGF and SIF. Glutaraldehyde treatment suppressed catechin release in all tested media. These results suggest that internally gelled CPG beads are suitable for catechin delivery, and crosslinkers, such as glutaraldehyde, can effectively sustain their release.

Effects of Combination Oral Contraceptives on Bone Mineral Density and Metabolism in Perimenopausal Korean Women.

OBJECTIVES: A retrospective cohort study was conducted to evaluate the effects of combination oral contraceptives (COCs) on bone mineral density (BMD) and metabolism in perimenopausal Korean women. METHODS: The study subjects comprised two groups. The COC group included 55 women who took low-dose COC for at least one year to control vasomotor symptoms. Another 55 women who had annual checkups without history of COC use served as controls. BMD and bone turnover markers were assessed periodically. RESULTS: In the control group, 12-month BMD values at the lumbar spine (LS) and total hip (TH) significantly decreased with a greater magnitude at LS, and bone resorption (BR) and formation (BF) markers increased concurrently with a larger change in BR. COCs increased BMD at LS after 12 months and prevented BMD decline at TH. Multivariable linear regression revealed a significant difference in LS BMD between groups at 12 months. In the COC group, there were significant negative correlations between baseline BMD and Z-score at LS and corresponding changes at 12 months. COCs did not alter BR markers, whereas BF markers were significantly decreased at 3 months. Group comparison at 12 months, as tested with adjusted linear regression, disclosed significant differences in both BR and BF makers. CONCLUSIONS: Bone loss associated with activated bone turnover is evident during the menopausal transition, and COCs might prevent BMD decrease and suppress bone turnover markers in perimenopausal Korean women. Significant increase in LS BMD and decreases in BF makers suggest underlying mechanisms of greater impact on BF.

Chitosan-Tripolyphosphate Nanoparticles Prepared by Ionic Gelation Improve the Antioxidant Activities of Astaxanthin in the In Vitro and In Vivo Model.

The present study aimed to investigate the effects of chitosan (CS)-tripolyphosphate (TPP) nanoparticles (NPs) on the stability, antioxidant activity, and bioavailability of astaxanthin (ASX). ASX-loaded CS-TPP NPs (ACT-NPs) prepared by ionic gelation between CS (0.571 mg/mL) and TPP (0.571 mg/mL) showed 505.2 ± 184.8 nm, 20.4 ± 1.2 mV, 0.348 ± 0.044, and 63.9 ± 3.0% of particle size, zeta potential, polydispersity index and encapsulation efficiency, respectively. An in vitro release study confirmed that the release of ASX in simulated gastric (pH 1.2) and intestinal (pH 6.8) fluid was prolonged within ACT-NPs. The in vitro antioxidant activities of ACT-NPs were significantly improved compared with free ASX (FA) (p < 0.05). Furthermore, the cellular and in vivo antioxidant analysis verified that ACT-NPs could enhance the cytoprotective effects on the BHK-21 cell line and demonstrate sustained release properties, leading to prolonged residence time in the rat plasma. The results suggest that the stability, antioxidant properties, and bioavailability of ASX can be effectively enhanced through encapsulation within CS-TPP NPs.

Association between Visceral Adipose Tissue Metabolism and Alzheimer's Disease Pathology.

The visceral adipose tissue (VAT) has been recognized as an endocrine organ, and VAT dysfunction could be a risk factor for Alzheimer's disease (AD). We aimed to evaluate the association of VAT metabolism with AD pathology. This cross-sectional study included 54 older subjects with cognitive impairment who underwent 2-deoxy-2-[fluorine-18]-fluoro-D-glucose (18F-FDG) torso positron emission tomography (PET) and 18F-florbetaben brain PET. 18F-FDG uptake in VAT on 18F-FDG PET images was used as a marker of VAT metabolism, and subjects were classified into high and low VAT metabolism groups. A voxel-based analysis revealed that the high VAT metabolism group exhibited a significantly higher cerebral amyloid-ß (Aß) burden than the low VAT metabolism group. In the volume-of-interest analysis, multiple linear regression analyses with adjustment for age, sex, and white matter hyperintensity volume revealed that 18F-FDG uptake in VAT was significantly associated with the cerebral Aß burden (ß = 0.359, p = 0.007). In conclusion, VAT metabolism was associated with AD pathology in older subjects. Our findings suggest that VAT dysfunction could contribute to AD development.

Antimicrobial and indicator properties of edible film containing clove bud oil-loaded chitosan capsules and red cabbage for fish preservation.

For safe preservation and consumption of fish, freshness monitoring and antimicrobial control is crucial. Edible films comprising natural antimicrobial and spoilage indicator agents represent a convenient method for such preservation. Edible chitosan-based films were prepared using red cabbage (RC) and clove bud oil (CBO)-loaded chitosan/carrageenan capsules as spoilage indicator and antimicrobial agents, respectively. CBO-loaded capsules were prepared by the ionic gelation of chitosan and carrageenan. Films containing CBO capsules exhibited significantly higher antimicrobial activity than films containing non-encapsulated free CBO, as confirmed by minimum inhibitory concentration and time-kill assays. The highest antimicrobial activity was observed in the largest capsules (1.7 µm). After incubation for 48 h, the pH of fish peptone agar containing Pseudomonas fluorescens increased from approximately 6.0 to 9.0, and a color change from purple to deep blue was clearly observed during the growth of fish-spoiling bacteria. Thus, our results suggested that edible films containing CBO-loaded capsules and RC showed the potential to inhibit microbial growth in fish and to visibly indicate fish freshness.

Skimmed milk fermented by lactic acid bacteria inhibits adipogenesis in 3T3-L1 pre-adipocytes by downregulating PPARγ via TNF-α induction in vitro.

The murine 3T3-L1 pre-adipocyte cell line is widely used as an in vitro model for adipogenesis because of its similarities to primary fat cells. The aim of this study was to investigate the intracellular mechanisms by which skimmed milk fermented by two lactic acid bacteria (LAB), Enterococcus faecalis and Lactobacillus plantarum, inhibited the differentiation of 3T3-L1 pre-adipocytes. Skimmed milk fermented by both LAB, but not non-fermented skimmed milk, significantly reduced the accumulation of lipid droplets and cellular triglycerides in a concentration-dependent manner. The mRNA and protein levels of peroxisome proliferator-activated receptor γ (PPARγ) were markedly inhibited in the presence of skimmed milk fermented by both LAB. Furthermore, the skimmed milk fermented by both LAB decreased the mRNA and protein expressions of PPARγ-targeting genes, lipoprotein lipase and adipocyte fatty acid-binding protein. Under the same circumstances, resistin mRNA expression was downregulated, but not leptin mRNA expression. In contrast, skimmed milk fermented by both LAB significantly upregulated tumor necrosis factor-α (TNF-α). These results suggest that LAB-fermented skimmed milk inhibits adipogenesis by inhibiting a master transcription factor PPARγ via the upregulation of the proinflammatory cytokine TNF-α in 3T3-L1 cells.

Intramyocardial delivery of human cardiac stem cell spheroids with enhanced cell engraftment ability and cardiomyogenic potential for myocardial infarct repair.

Strategies for stem cell-based cardiac regeneration and repair are key issues for the ischemic heart disease (IHD) patients with chronic complications related to ischemic necrosis. Cardiac stem cells (CSCs) have demonstrated high therapeutic efficacy for IHD treatment owing to their specific cardiac-lineage commitment. The therapeutic potential of CSCs could be further enhanced by designing a cellular spheroid formulation. The spheroid culture condition of CSCs was optimized to ensure regulated size and minimal core necrosis in the spheroids. The CSC spheroids revealed mRNA profiles of the factors related to cardiac regeneration, angiogenesis, anti-inflammatory, and cardiomyocyte differentiation with a higher expression level than the CSCs. Intramyocardially delivered CSC spheroids in the rat IHD model resulted in a significant increase in retention rate by 1.82-fold (day 3) and 1.98-fold (day 14) compared to CSCs. Endothelial cell differentiation and neovascularization of the engrafted CSC spheroids were noted in the infarcted myocardium. CSC spheroids significantly promoted cardiac regeneration: i.e., decreased infarction and fibrotic area (11.22% and 4.18%) and increased left ventricle thickness (0.62 mm) compared to the untreated group. Cardiac performance was also improved by 2.04-fold and 1.44-fold increase in the ejection fraction and fractional shortening, respectively. Intramyocardial administration of CSC spheroids might serve as an advanced therapeutic modality with enhanced cell engraftment and regenerative abilities for cardiac repair after myocardial infarction.

Bacteriocin-Like Inhibitory Substance (BLIS) Activity of Enterococcus faecium DB1 Against Biofilm Formation by Clostridium perfringens.

The antibiofilm effect of bacteriocin-like inhibitory substance (BLIS) from Enterococcus faecium DB1 against Clostridium perfringens was investigated in the present study. BLIS of E. faecium DB1 significantly reduced biofilm formation by C. perfringens in a dose-dependent manner for 24 and 48 h. In particular, treatment with BLIS of E. faecium DB1 significantly inhibited biofilm formation by C. perfringens on chicken meat and stainless steel coupon surfaces. Moreover, BLIS of E. faecium DB1 decreased the viability of C. perfringens biofilm and planktonic cells, indicating that the reduction of biofilm formation by C. perfringens might be achieved by killing the bacterial cells. Taken together, the present results suggest that BLIS of E. faecium DB1 can be a promising antibiofilm agent to eradicate C. perfringens.

Quercetin delivery characteristics of chitosan nanoparticles prepared with different molecular weight polyanion cross-linkers.

The aim of the study was to investigate the effects of cross-linkers on quercetin (QUE) absorption characteristics of QUE-loaded chitosan nanoparticles (CS-NPs). CS-NPs (461.2-482.7 nm) were prepared by ionic gelation at pH 3.5 using tripolyphosphate (367.9 Da), dextran sulfate (>15 kDa), arabic gum (AG, >250 kDa), or hyaluronic acid (HA, >1000 kDa). Mucoadhesion and cell permeation of QUE were significantly increased by positive charged CS-NPs due to interactions with negatively charged mucosal layer. Moreover, CS-AG and CS-HA NPs prepared with relatively higher MW cross-linkers exhibited significantly higher adhesion and permeation than the others. These results were verified by a cellular antioxidant activity assay; CS-AG (137.5 unit) and CS-HA NPs (126.5 unit) showed significantly higher activities after internalization into Caco-2 cells. Therefore, encapsulation within CS-NPs prepared using high MW cross-linkers such as AG and HA is found to be potentially valuable techniques for improving the QUE absorption.

Hygroscopic behavior and chemical reactivity of aerosols generated from mixture solutions of low molecular weight dicarboxylic acids and NaCl.

Ambient sea spray aerosols (SSAs) have been reported to undergo reactions with low molecular weight dicarboxylic acids (LMW DCAs). In the present study, the hygroscopic behavior of aerosols generated from NaCl-LMW DCA mixture solutions with different mixing ratios was explained. In situ Raman microspectrometry (RMS) was used to simultaneously monitor the alterations in chemical composition, size, and phase as a function of the relative humidity (RH) for individual aerosols. The observation of individual mixture aerosols revealed chemical reactions on the timescale of one hour in the aqueous phase, mostly during the dehydration process, leading to the formation of sodium salts of DCAs with distinct reactivities among different DCAs and mixing ratios, which in turn exhibited diverse hygroscopic behaviors. The NaCl-DCA mixture aerosols were either in a ternary NaCl-DCA-DCA sodium salt system or a binary NaCl-DCA sodium salt or DCA-DCA sodium salt system, instead of a binary NaCl-DCA system when experiencing the hygroscopic process. The chemical compositional evolution of the NaCl-DCA aerosols during the hygroscopic measurements was examined based on the Raman spectra acquired for aqueous, amorphous, and/or crystalline pure standard aerosols at specific RHs. The different reactivity observed among the DCAs with different mixing ratios suggests that the reactivity driven by the irreversible liberation of HCl is governed mainly by the available aqueous H+ because Cl- is always available in the aqueous NaCl-DCA aerosols until the complete consumption of NaCl.