Age-group-specific association of oral health and systemic health on cognitive function: a cross-sectional study of Korean elders.

BACKGROUND: Although the importance of oral and systemic healthcare for elderly people is increasing owing to the rapid ageing of the population in South Korea, studies on the relationship between oral health, systemic health, and cognitive function, as well as on the prediction of cognitive function by oral and systemic health depending upon age groups are lacking. METHODS: We included 5,975 out of 6,488 participants from the 8th wave of the Korean Longitudinal Study of Aging (KLoSA) panel data, divided the participants into three age groups, and performed a hierarchical multiple linear regression analysis to explain cognitive function with four types of predictors: oral health status, sociodemographic factors, objective health status, and subjective health status. RESULTS: Oral health status was positively correlated with systemic health status and cognitive function. Of all ages over 54, cognitive function was significantly predicted by oral health variables, such as the number of functional teeth, masticatory ability, and Geriatric Oral Health Assessment Index (GOHAI); sociodemographic variables, such as age, sex, education level, and residence; and systemic health variables, such as diagnosis of diabetes mellitus, cancer or malignant tumours, cerebrovascular disease and rheumatoid arthritis, depressive symptom, and self-rated health status. Oral health variables explained cognitive function differently by age group; GOHAI appeared important predictor in the group aged < 75 years, whereas the number of functional teeth did in the group aged ≥ 75 years. Educational level, masticatory ability, depressive symptoms, and self-rated health status were pivotal factors age-independently. CONCLUSIONS: The general and age-group-specific association between oral health, systemic health, and cognitive function were confirmed, suggesting that age-group-specific oral healthcare should be emphasized for the effective management of systemic and cognitive health in the elderly group.

Sustained activation of persulfate by slow release of Fe(II) from silica-coated nanosized zero-valent iron for in situ chemical oxidation.

Sustained activation of persulfate through the slow release of Fe(II) from silica-coated nanosized zero-valent iron (nZVI) particles (nZVI@SiO2) was investigated. Slow release of Fe(II) prevented radical scavenging by excess Fe(II) and increased the radical yield, which improved the stoichiometric efficiency of phenol degradation. Sulfate and hydroxyl radicals were found to be the main oxidative species produced during phenol degradation and were found to make comparable contributions to oxidation. The nZVI@SiO2 particle silica shell thickness controlled the release of Fe(II) and therefore the sustained activation of persulfate and was strongly affected by the synthesis conditions, including the [Si]/[Fe] ratio and silica supply rate. Optimal sustained phenol degradation was achieved when nZVI@SiO2 particles were synthesized using a [Si]/[Fe] ratio of 0.5 and a tetraethyl orthosilicate supply rate of 0.5 mL/min, and this was attributed to the nZVI@SiO2 particles giving an optimal Fe(II) release rate and therefore a high persulfate activation rate and a high phenol removal efficiency. Sustained persulfate activation induced by Fe(II) being slowly released was described well by single-stage first-order kinetics rather than two-stage first-order kinetics typical of unmodified nZVI/persulfate systems. Persulfate was found still to be activated by iron (oxyhydr)oxides minerals after the nZVI@SiO2 particles had been exhausted but the persulfate sustained activation induced by the slow release of Fe(II) played a crucial role in determining the overall degradation efficiency. The results highlight the importance of the slow release of Fe(II) from nZVI-based materials for in situ chemical oxidation through sustained persulfate activation.

Antimicrobial activity of Limosilactobacillus fermentum strains isolated from the human oral cavity against Streptococcus mutans.

Oral probiotics have been recently gaining much attention owing to their potential to inhibit the progression of dental caries by controlling the cariogenic effects of Streptococcus mutans. We isolated and genotypically identified 77 lactic acid bacteria including 12 Limosilactobacillus fermentum probiotic candidates from the oral cavity of healthy volunteers. Among the 12 L. fermentum isolates, nine isolates effectively inhibited the growth of S. mutans via hydrogen peroxide (H2O2) production. The others neither suppressed the growth of S. mutans nor produced H2O2. Eight out of the nine H2O2-producing L. fermentum isolates exhibited strong adherence to oral epithelial KB cells while inhibiting the adherence of S. mutans to KB cells. The eight H2O2-producing isolates were neither haemolytic based on a blood-agar test, cytotoxic according to lactate dehydrogenase assay, nor resistant to eight antibiotics represented by the European Food Safety Authority guideline, indicating that the isolates have potential to suppress the cariogenesis driven by S. mutans while providing general probiotic benefits.

Standard operating procedures for the collection, processing, and storage of oral biospecimens at the Korea Oral Biobank Network.

PURPOSE: The Korea Oral Biobank Network (KOBN) was established in 2021 as a branch of the Korea Biobank Network under the Korea Centers for Disease Control and Prevention to provide infrastructure for the collection, management, storage, and utilization of human bioresources from the oral cavity and associated clinical data for basic research and clinical studies. METHODS: To address the need for the unification of the biobanking process, the KOBN organized the concept review for all the processes. RESULTS: The KOBN established standard operating procedures for the collection, processing, and storage of oral samples. CONCLUSIONS: The importance of collecting high-quality bioresources to generate accurate and reproducible research results has always been emphasized. A standardized procedure is a basic prerequisite for implementing comprehensive quality management of biological resources and accurate data production.

Evaluation of the use of biochar to stabilize polycyclic aromatic hydrocarbons and phthalates in sediment.

Three types of biochar (BC) (mulberry biochar (MB), wheat straw biochar, and pine tree sawdust biochar) were prepared and used to stabilize hydrophobic organic compounds (HOCs) in contaminated sediment. The kinetics of HOC adsorption to the BCs had two distinct stages. The second stage adsorption process was longer for MB than the other BCs, presumably because MB contained large pores, mesopores, and micropores. The adsorption isotherms for the three BCs were described well by the Freundlich model. The adsorption capacities of MB, WS and PT for HOCs ranged between 106.7 and 1202 µg/g, 135.1 and 1002 µg/g, and 255.6 and 909 µg/g, respectively. The apparent HOC adsorption coefficients (KBC-w) for the three BCs were determined from the isotherm data and were similar. The HOC logKOW values correlated well with the logKBC-w values. In sediment slurry experiments, HOCs were much more effectively stabilized by MB than wheat straw and pine tree sawdust biochar. This was probably because of the MB pore characteristics that favored adsorption of HOCs of various molecular sizes. The Fourier-transform infrared and Raman spectra indicated that the main binding mechanisms were hydrogen boding, hydrophobic interactions, and π-π interactions. MB was found to be a possible agent for stabilizing HOCs in contaminated sediment. HOCs in sediment slurry continued to become adsorbed to MB for a long time, indicating that relatively long reaction times should be allowed for in situ remediation using MB.

Post-Treatment of Tannic Acid for Thermally Stable PEDOT:PSS Film.

As a poly (3,4-ethylenedioxythiophene) doped with poly (styrene sulfonate), PEDOT:PSS is well known for its conductive polymer in a field of organic electronics. PEDOT:PSS can be widely operated as electronics under low temperature conditions; however, the layer can be easily damaged by high temperature conditions, while in fabrication or in the operation of electronics. Therefore, enhancing the thermal stability of PEDOT:PSS can be a novel strategy for both fabrication and operating varieties. Herein, PEDOT:PSS is the surface-treated with tannic acid to increase the thermal stability. A large number of phenols in tannic acid not only provide UV absorption ability, but also thermal stability. Therefore, tannic-treated PEDOT:PSS film sustained 150 °C for 96 h because of its initial conductivity. Moreover, surface properties and its bonding nature was further examined to show that the tannic acid does not damage the electrical and film properties. The method can be widely used in the field of organic electronics, especially because of its high stability and the high performance of the devices.

Complete Genome Sequence of Hydrogen Peroxide-Producing Limosilactobacillus fermentum DM072 Isolated from the Human Oral Cavity.

The complete genome of hydrogen peroxide (H2O2)-producing Limosilactobacillus fermentum strain DM072, isolated from the oral cavity of healthy volunteers in South Korea, was sequenced by long-read sequencing and was subsequently corroborated by short-read sequencing. The genome comprises one circular chromosome and one plasmid and lacks antimicrobial resistance genes.

Complete Genome Sequence of Lacticaseibacillus rhamnosus DM065, Isolated from the Human Oral Cavity.

The 3.0-Mb complete genome of Lacticaseibacillus rhamnosus strain DM065, which was isolated from the oral cavity of healthy volunteers in South Korea, was sequenced using a combination of PacBio and Illumina technologies. The genome consists of one circular chromosome and two plasmids and lacks antimicrobial resistance genes.

Association between body mass index and subcortical volume in pre-adolescent children with autism spectrum disorder: An exploratory study.

Conflicting associations exist between autism spectrum disorder (ASD) and subcortical brain volumes. This study assessed whether obesity might have a confounding influence on associations between ASD and brain subcortical volumes. A comprehensive investigation evaluating the relationship between ASD, obesity, and subcortical structure volumes was conducted. Data obtained included body mass index (BMI) and T1-weighted structural magnetic resonance images for children with and without ASD diagnoses from the Autism Brain Imaging Data Exchange database. Brain subcortical volumes were calculated using vol2Brain software. Hierarchical linear regression analyses were performed to explore the subcortical volumes similarly or differentially associated with BMI in children with or without ASD and examine association and interaction effects regarding ASD and subcortical volume impact on the Social Responsiveness Scale and Vineland Adaptive Behavior Scale (VABS) scores. Bilateral caudate nuclei were smaller in children with ASD than in control participants. Significant interactions were observed between ASD diagnosis and BMI regarding the left caudate, right and left putamen, and right and left ventral diencephalon (DC) volumes (ß = -0.384, p = 0.010; ß = -0.336, p = 0.030; ß = -0.317, p = 0.040; ß = 0.322, p = 0.010; ß = 0.295, p = 0.021, respectively) and between ASD diagnosis and right and left ventral DC volumes regarding the VABS scores (ß = 0.434, p = 0.014; ß = 0.495, p = 0.007, respectively). However, each subcortical structure volume included in the ventral DC area could not be measured separately. The results identified subcortical volumes differentially associated with obesity in children with ASD compared with typically developing peers. BMI may need to be considered an important confounder in future research examining brain subcortical volumes within ASD.

Whole-Genome Sequence of Limosilactobacillus fermentum Strain DM075, Isolated from the Human Oral Cavity.

Here, we report the complete genome sequence of nitric oxide (NO)-producing Limosilactobacillus fermentum strain DM075, which was isolated from human tongue coating samples from healthy donors in South Korea. The complete genome sequence of DM075 comprises a single circular 2,204,022-bp genome, with a GC content of 51.0%, and lacks antimicrobial resistance genes.

Continuous Fe(II)-dosing scheme for persulfate activation: Performance enhancement mechanisms in a slurry phase reactor.

Mechanisms involved in the superior performance of the continuous Fe2+ dosing scheme over the single Fe2+ dosing scheme was thoroughly investigated. The kinetics and stoichiometry of the phenol removal/persulfate consumption strongly depended on the volumetric or molar Fe2+ feeding rate, Fe2+ concentration in the feed solution, and Fe2+ feeding mode (continuous or single dose). The process performance was determined by the molar Fe2+ feeding rate rather than the volumetric Fe2+ feeding rate or the Fe2+ concentration in the feed solution. The phenol degradation rate increased as the molar Fe2+ feeding rate increased to 2.77 mmol/min but decreased as the Fe2+ feeding rate increased further. The sulfate radical was predominant radical species formed in continuous Fe2+ dosing mode. The hydroxyl and sulfate radicals were both important in single Fe2+ dose mode. The presence of hydroxyl radicals in single Fe2+ dosing mode decreased the amount of phenol oxidation that occurred, probably because the hydroxyl radicals were readily scavenged by soil organic matter. Continuous Fe2+ dosing facilitated phenol mineralization, which was indicated by total organic carbon measurements and toxicity tests performed using Hyalella azteca.

Complete Genome Sequence of Lactiplantibacillus plantarum Strain DM083 Isolated from Human Tongue Coating.

We isolated Lactiplantibacillus plantarum DM083 from the human tongue coating to establish a strain library for oral probiotics. It has a single circular 3,197,299 bp chromosome with a guanine-cytosine (GC) content of 44.6% without plasmids. Importantly, the genome is devoid of the antimicrobial resistance gene, satisfying the minimum safety requirement for probiotics.

Capacitive humidity sensing properties of freestanding bendable porous SiO2/Si thin films.

The fabrication of freestanding bendable films without polymer substrates is demonstrated as a capacitive humidity-sensing material. The bendable and porous SiO2/Si films are simply prepared by electrochemical-assisted stripping, metal-assisted chemical etching, followed by oxidation procedures. The capacitive humidity-sensing properties of the fabricated porous SiO2/Si film are characterized as a function of the relative humidity and frequency. The remarkable sensing performance is demonstrated in the wide RH range from 13.8 to 79.0%. The sensing behavior of the porous SiO2/Si film is studied by electrochemical impedance spectroscopy analysis. Additionally, the reliability of the porous SiO2/Si sensing material is confirmed by cyclic and long-term sensing tests.

Leaky Gum: The Revisited Origin of Systemic Diseases.

The oral cavity is the gateway for microorganisms into your body where they disseminate not only to the directly connected respiratory and digestive tracts but also to the many remote organs. Oral microbiota, travelling to the end of the intestine and circulating in our bodies through blood vessels, not only affect a gut microbiome profile but also lead to many systemic diseases. By gathering information accumulated from the era of focal infection theory to the age of revolution in microbiome research, we propose a pivotal role of "leaky gum", as an analogy of "leaky gut", to underscore the importance of the oral cavity in systemic health. The oral cavity has unique structures, the gingival sulcus (GS) and the junctional epithelium (JE) below the GS, which are rarely found anywhere else in our body. The JE is attached to the tooth enamel and cementum by hemidesmosome (HD), which is structurally weaker than desmosome and is, thus, vulnerable to microbial infiltration. In the GS, microbial biofilms can build up for life, unlike the biofilms on the skin and intestinal mucosa that fall off by the natural process. Thus, we emphasize that the GS and the JE are the weakest leaky point for microbes to invade the human body, making the leaky gum just as important as, or even more important than, the leaky gut.

Activation of persulfate by humic substances: Stoichiometry and changes in the optical properties of the humic substances.

Persulfate activation through electron transfer from humic substances (HS) was investigated. Persulfate consumption in the presence of standard HS and HS model compounds linearly correlated with the phenol contents of the HS. Redox-active carbonyl groups such as aromatic ketones and quinone also contributed to persulfate consumption by donating electrons while being reduced. Phenols activated persulfate through direct electron transfer from the phenolate forms but reduced ketones activated persulfate through reactions between their organic radicals and persulfate. Persulfate was activated more by terrestrially derived aquatic HS containing large numbers of phenol groups than by other species, and this caused more benzene oxidation to occur in the presence of terrestrially derived aquatic HS than in the presence of other species. Larger amounts of sulfate radicals were scavenged by soil-derived HS than other types of HS because soil-derived HS were composed of larger molecules than other types of HS. The fluorescence regional integration volume for HS reacted with persulfate linearly correlated with persulfate consumption. Decreases in the fluorescence regional integration value could be used to predict persulfate activation through electron transfer from HS to persulfate if the electron-donating capacity cannot be determined. Persulfate activation by HS is expected to be stoichiometrically more advantageous than conventional persulfate-Fe2+ processes when treating an aquifer containing large amounts of electron-rich HS.

Field-scale investigation of nanoscale zero-valent iron (NZVI) injection parameters for enhanced delivery of NZVI particles to groundwater.

The effects of the injection parameters on delivery of nanoscale zero-valent iron (NZVI) to contaminated groundwater were investigated. The first two NZVI injections (gravity injection at low flow rates) resulted in NZVI being poorly mobile and gave total cumulative mass recoveries at the monitoring wells of 1.07%-2.43%. NZVI reached some wells (KDMW-3, MW-2, MW-4, and MW-7) earlier than the bromide tracer. The dominant travel directions for NZVI and the bromide tracer were very different. The NZVI transport characteristics suggested that targeted NZVI delivery requires preferential groundwater flow paths and local heterogeneity to be considered. In the gravity injection tests, the maximum NZVI concentrations and cumulative NZVI mass recoveries in the wells decreased markedly as the injected NZVI concentration and dose increased. In the third and fourth tests, in which NZVI was injected under pressure at high flow rates, NZVI was effectively delivered to the wells despite the injected NZVI concentration and dose being high. Relatively high cumulative mass recoveries of 26.0% and 74.5% were found for the third and fourth injections, respectively. Controlling the flow rate (pressure) and NZVI concentration and dose simply and effectively controlled NZVI mobility in the groundwater. The colloidal and electrostatic characteristics of the NZVI particles were monitored and modeled, and the results indicated that NZVI particles without Derjaguin-Landau-Verwey-Overbeek energy barriers were successfully delivered to the target zone and that decreased magnetic attractive forces between NZVI particles caused by iron corrosion probably decreased the degree of NZVI particle aggregation and therefore contributed to NZVI being delivered to the target zone.

Laboratory and field study on changes in water quality and increase in dissolved iron during riverbank filtration.

Changes in the water quality by the riverbank filtration (RBF) process were investigated in the field-scale demonstration sites. The overall water quality was improved by RBF, but Fe2+ concentration significantly increased in the riverbank-filtered water more than in the river water. This result would be caused by the interaction between the iron minerals and the river water in the aquifer and the influx of the hinterland groundwater into RBF wells. Dissolution properties of iron from the aquifer soils cored at the sites were evaluated through incubation experiment considering various values of redox potential (Eh), dissolved oxygen (DO), and hydrogen-ion concentration exponent (pH). These results presented that at the incubator with the final Eh of 470 mV, DO of 3.4, and pH of 4.53, the iron from the aquifer soil was most dissolved, and the pyrite and siderite contents in the aquifer soil decreased significantly from 11.5 to 6.22% and from 50.8 to 24.5%, respectively. Based on changes of ion concentrations (such as Fe2+, Fe3+, SO42- and NO3-) and iron species in the incubators, it was believed that pyrite and siderite minerals in the aquifer soils cause an increase in the Fe2+ concentration with the absence of DO and an increase in the Fe2+ and Fe3+ concentrations with the presence of DO. The dissolution rates of iron minerals into Fe2+ and Fe3+ were dependent on Eh, pH, and DO and were more sensitive to Eh and pH than DO. The results of this study can provide information on RBF site selection and its operation.

Colloidal activated carbon as a highly efficient bifunctional catalyst for phenol degradation.

A preparation of colloidal activated carbon (CAC) for phenol remediation from groundwater was introduced. The CAC prepared by a simple pulverization technique was an excellent metal-free catalyst for persulfate (PS) activation due to high contact surface area. The removal efficiency of phenol in the PS/CAC system (~100%) was higher than that in the PS/activated carbon (AC) system (90.1%) and was superior to the conventional PS/Fe2+ system (27.9%) within 30 min. The phenol removal reaction occurred both in bulk solution and at the surface of the CAC, as confirmed by Langmuir-Hinshelwood (L-H) kinetic model fitting, FT-IR, and electron spin resonance (ESR) analyses. The downsizing of particle size from AC to CAC played a critical role in the radical oxidation mechanism by leading to the formation of predominant superoxide radical (O2•-) species in the PS/CAC system. Anions NO3-, SO42-, and Cl- slightly inhibited the phenol removal efficiency, whereas CO32-, HCO3- and PO43- did not. Ferulic acid (C10H10O4) was detected as an organic byproduct of phenol oxidation. The use of CAC as a metal-free bifunctional catalyst has an important implication in the PS activation for phenol degradation in groundwater.

Topological analysis of single-stranded DNA with an alpha-hederin nanopore.

Nanopores have been emerged as a powerful tool for analyzing the structural information and interactional properties of a range of biomolecules. The spatial resolution of nanopore is determined by the diameter and effective thickness of its constriction region, but the presence of vestibule or stem structure in protein-based nanopore could negatively affect the sensitivity of the nanopore when applied for genome sequencing and topological analysis of DNA. Recently, alpha-hederin (Ah) has been reported to form a sub-nanometer scale pore structure in lipid membrane. With the simple structure and extremely small effective thickness, the Ah nanopore was shown to discriminate four different types of nucleotides. However, identification of a certain nucleotide in a strand of DNA, which is essential for genome sequencing, remains challenging. Here, we investigated the resolving capability of Ah nanopore to discriminate few nucleotides in a strand of single-stranded DNA, and the factors determining the sensitivity of Ah nanopore. The Ah nanopore was shown to be able to identify as few as three adenosine nucleotides in a strand of poly cytidine, in which the dwell time of the additional current blockade that represents the adenosine residue was in good agreement with their physical length. We also found that the lateral tension and chain pressure generated around the nanopore were influenced by pore's diameter and played as a dependent variables to determine the geometry of nanopore's constriction as well as the spatial resolution of the Ah nanopore.

Salivary biomarkers in oral squamous cell carcinoma.

In disease diagnostics and health surveillance, the use of saliva has potential because its collection is convenient and noninvasive. Over the past two decades, the development of salivary utilization for the early detection of cancer, especially oral cavity and oropharynx cancer has gained the interest of the researcher and clinician. Until recently, the oral cavity and oropharynx cancers are still having a five-year survival rate of 62%, one of the lowest in all major human cancers. More than 90% of oral cancers are oral squamous cell carcinoma (OSCC). Despite the ease of accessing the oral cavity in clinical examination, most OSCC lesions are not diagnosed in the early stage, which is suggested to be the main cause of the low survival rate. Many studies have been performed and reported more than 100 potential saliva biomarkers for OSCC. However, there are still obstacles in figuring out the reliable OSCC salivary biomarkers and the clinical application of the early diagnosis protocol. The current review article discusses the emerging issues and is hoped to raise awareness of this topic in both researchers and clinicians. We also suggested the potential salivary biomarkers that are reliable, specific, and sensitive for the early detection of OSCC.