Assessment of heavy metal pollution in the coastal sediments of an urbanized atoll in the central Pacific: Majuro Atoll, the Marshall Islands.

Pacific atolls are extremely vulnerable to the effects of climate change. Coral reef ecosystems, which are responsible for the island formation and maintenance, can potentially keep pace with rising sea levels. Such ecosystems are sensitive to pollution; however, the sources and levels of atoll pollutants caused by urbanization have rarely been investigated. In this study, we assessed the heavy metal pollution (Cr, Mn, Ni, Cu, Zn, Cd, and Pb) of coastal sediments to evaluate the effects of urbanization on Majuro Atoll, the Marshall Islands. The densely populated area had the most significant pollution with high levels of Pb, Mn, Zn, and Cu due to road traffic activity. Domestic wastewater, a major pollution source in Pacific atolls, was not identified. Remarkably, the Zn and Pb levels in the lagoonal coasts of the remote island area were 697 - 1539 and 22 - 337 times higher, respectively, than in the natural area of Funafuti Atoll, Tuvalu. Thus, the remote island and sparsely populated areas were significantly polluted because of the maritime traffic activity in the lagoon and debris accumulation in/around the lagoon. This pollution resulted from improper municipal solid waste management of the main island. The contamination factor, pollution load index, and geo-accumulation index indicated high levels of heavy metal pollution in these areas. Urbanization of the atoll clearly resulted in a distinct heavy metal composition and high pollution levels compared with Funafuti Atoll. These findings emphasize the importance of pollution management in the conservation and rehabilitation of urbanized atolls threatened by future sea-level rises.

Gastric emptying rate before and after orthodontic treatment examined with the [13C] breath test: A pilot study.

INTRODUCTION: Orthodontic patients with malocclusion have significantly lower masticatory and gastrointestinal digestive function than persons with normal occlusion. Although several studies have suggested that masticatory function is improved after orthodontic treatment, the relationship between such improvement and change in gastrointestinal symptoms has not been quantitatively evaluated. In this study, we aimed to investigate the change in masticatory function and the gastric emptying rate in patients with malocclusion, before and after orthodontic treatment. METHODS: Seven women with malocclusion, before (pretreatment group) and after orthodontic treatment (posttreatment group), and 7 healthy dentate female volunteers (control group) underwent a 13C-acetate breath test (13CO2) with a liquid meal and the color changeable gum test, along with completing the frequency scale for symptoms of gastroesophageal reflux and a questionnaire on food intake. Between-group differences were evaluated. RESULTS: The pretreatment group had significantly longer maximum 13CO2 exhalation time and lower masticatory function, quantified using a higher red-color value on the gum test and the questionnaire on food intake, than did the posttreatment and control groups. No significant differences were identified between the posttreatment and the control groups. CONCLUSIONS: We provide evidence of improvement of masticatory function after orthodontic treatment, which was associated with a faster rate of gastric emptying.

Assessment of Multidimensional Health Care Parameters Among Adults in Japan for Developing a Virtual Human Generative Model: Protocol for a Cross-sectional Study.

BACKGROUND: Human health status can be measured on the basis of many different parameters. Statistical relationships among these different health parameters will enable several possible health care applications and an approximation of the current health status of individuals, which will allow for more personalized and preventive health care by informing the potential risks and developing personalized interventions. Furthermore, a better understanding of the modifiable risk factors related to lifestyle, diet, and physical activity will facilitate the design of optimal treatment approaches for individuals. OBJECTIVE: This study aims to provide a high-dimensional, cross-sectional data set of comprehensive health care information to construct a combined statistical model as a single joint probability distribution and enable further studies on individual relationships among the multidimensional data obtained. METHODS: In this cross-sectional observational study, data were collected from a population of 1000 adult men and women (aged ≥20 years) matching the age ratio of the typical adult Japanese population. Data include biochemical and metabolic profiles from blood, urine, saliva, and oral glucose tolerance tests; bacterial profiles from feces, facial skin, scalp skin, and saliva; messenger RNA, proteome, and metabolite analyses of facial and scalp skin surface lipids; lifestyle surveys and questionnaires; physical, motor, cognitive, and vascular function analyses; alopecia analysis; and comprehensive analyses of body odor components. Statistical analyses will be performed in 2 modes: one to train a joint probability distribution by combining a commercially available health care data set containing large amounts of relatively low-dimensional data with the cross-sectional data set described in this paper and another to individually investigate the relationships among the variables obtained in this study. RESULTS: Recruitment for this study started in October 2021 and ended in February 2022, with a total of 997 participants enrolled. The collected data will be used to build a joint probability distribution called a Virtual Human Generative Model. Both the model and the collected data are expected to provide information on the relationships between various health statuses. CONCLUSIONS: As different degrees of health status correlations are expected to differentially affect individual health status, this study will contribute to the development of empirically justified interventions based on the population. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/47024.

Antioxidant capacity and carbon-based scope for growth of brackish water clams Corbicula japonica under the combined effects of natural and anthropogenic factors.

Changes in natural estuarine environment and anthropogenic disturbances are becoming significant threats to organisms, particularly bivalves. A deeper understanding of the relationship between biochemical- and individual-level responses is necessary to assess the combined effects of natural and anthropogenic factors on bivalves. To the best of our knowledge, this is the first study where the oxygen radical absorbance capacity (ORAC) and carbon-based scope for growth (C-SFG) were applied as biomarkers to evaluate the response of the brackish water clam Corbicula japonica to four spatiotemporally varying environmental factors. High water temperature and food availability supported C-SFG while high salinity inhibited it. Most of wastewater (WW) treatments resulted in negative C-SFG values because of a reduced clearance rate and increased excretion rate. In particular, high food availability with WW treatment resulted in the lowest C-SFG value of -114 µg C·ind-1 h-1. The ORAC was activated in response to high salinity with WW treatment (p < 0.05). To ascertain the combined effects of the natural and anthropogenic factors, principal component and cluster analyses were performed on the ORAC and C-SFG data. Anthropogenic WW was found to have different effects on the physiological and biochemical biomarkers according to the natural conditions. A roughly negative correlation was observed between ORAC and C-SFG because activation of the antioxidant capacity can influence the growth potential of the clams through the additional use of available metabolic energy. However, some exceptions were observed where both the ORAC and C-SFG values were either high or low, which could be because the C-SFG response varies depending on different metabolic behaviors even when the ORAC response remains the same. These results indicate that the biochemical-level response (i.e., ORAC) of C. japonica can be interpreted using individual-level response (i.e., C-SFG), but careful attention must be given to over- or underestimation.

Amorphous flexible covalent organic networks containing redox-active moieties: a noncrystalline approach to the assembly of functional molecules.

The organization states of functional molecules have a significant impact on the properties of materials. A variety of approaches have been studied to obtain well-organized molecular assemblies. The present work shows a new non-organized state of isolated and dispersed functional molecules in amorphous flexible covalent organic networks. Redox-active quinone molecules are embedded in the amorphous network polymers. Consecutive reactions between benzoquinone (BQ) and linker molecules generate random network structures through polymerization at different rates and in multiple directions. The low-crystalline stackings of the amorphous network polymers facilitate the formation of nanoflakes through exfoliation in dispersion media. Enhanced electrochemical performances, one of the highest specific capacities in recent studies, were achieved by efficient redox reactions of the quinone moiety. The present noncrystalline approach, low-crystalline stacking of designer amorphous covalent organic networks, can be applied to construct similar nanostructured polymer materials containing functional units.

Behavior of eukaryotic symbionts in large benthic foraminifers Calcarina gaudichaudii and Baculogypsina sphaerulata under exposure to wastewater.

Large benthic foraminifers (LBFs) are significant contributors to coral island formation in the Pacific Ocean. In recent years, the population of LBFs has decreased because of the increase in anthropogenic influences, such as wastewater (WW) discharge. To implement efficient mitigation measures, pollution tolerance in LBFs should be understood. However, the effects of WW on LBFs and their symbionts have not yet been demonstrated. This study examined the changes in the photosynthetic efficiency (Y[II]) of Calcarina gaudichaudii and Baculogypsina sphaerulata in response to WW by using a pulse-amplitude-modulation fluorometer. These LBFs were exposed to WW with different dilution levels for 22 days. The Y(II) values of the LBFs were found to deteriorate within 1-2 days. However, the Y(II) values both deteriorated and were enhanced in the experiments, thus indicating that WW contains both harmful and beneficial components. Baculogypsina sphaerulata showed an earlier response and greater sensitivity to WW and a higher epibiont infestation than C. gaudichaudii. This result can be attributed to the differences in the physiological and morphological responses of distinct LBFs. A sequencing analysis of 18S rDNA confirmed that the dominant eukaryotic symbionts in the two LBFs studied were Ochrophyta and Labyrinthulomycetes. These eukaryotic symbionts were released and attached as epibionts onto LBFs that were exposed to WW, thus leading to an increase in inactive LBFs. The Shannon-Weaver and Simpson diversity indices revealed that eukaryotic symbiont communities decreased in biodiversity after exposure to WW because of the abundance of algal symbionts. On the basis of these results, we conclude that WW, even with 10,000 × dilution, causes a decrease in active LBF populations owing to the release of eukaryotic symbionts, the decrease in biodiversity, and the infestation of epibionts even though Y(II) is temporarily enhanced. These responses are more significant in B. sphaerulata than in C. gaudichaudii.

Oxidative stress response of caddisfly Stenopsyche marmorata larvae to abrupt hypoxia-normoxia shift.

Natural and anthropogenic effects cause low dissolved oxygen conditions (hypoxia) and subsequent reoxygenated conditions (normoxia) in river systems. However, oxidative stress responses to hypoxia-normoxia shift in aquatic insects are still poorly understood. Here, we exposed caddisfly Stenopsyche marmorata larvae to 30-min hypoxic followed by 1-d normoxic exposure, with experiments being repeated at 14 °C (Exp.1) and 20 °C (Exp.2), respectively. Exp.1 was conducted in December 2016 using overwintering larvae, and Exp.2 was conducted in June 2016 using non-wintering larvae. The responses of superoxide dismutase (SOD) and catalase (CAT) activity, oxygen radical absorption capacity (ORAC), lipid peroxidation (LPO), and energy reserves were investigated. The hypoxia-normoxia shift considerably inhibited CAT and ORAC in Exp.1. In addition, the energy reserves were decreased in response to exposure to severe hypoxia-normoxia. However, LPO was not induced under these conditions. It is conceivable that regulating antioxidant defense enzymes and utilizing energy reserves may suppress the expected increases in LPO. In contrast, the hypoxia-normoxia shift in Exp.2 had almost no effect on oxidative stress response, with only ORAC being induced. Exp.1 had a lower dissolved oxygen partial pressure and a larger difference in the oxygen partial pressure between hypoxia and normoxia than Exp.2. The severity of hypoxia-normoxia shift and the differences in the life cycles (overwintering or non-wintering) may cause the difference in the response of ORAC in Exp.1 and Exp.2. This study revealed that the effect of the hypoxia-normoxia shift on oxidative stress response in aquatic insects and the strength of the impact of the shift on oxidative stress response may be influenced by water temperature and life cycles.

Assessing a polluted river environment by oxidative stress biomarker responses in caddisfly larvae.

The effluents of wastewater treatment plants (WWTPs) contain various anthropogenic pollutants that produce negative effects in river ecosystems. Although the oxidative stress responses in aquatic organisms are useful tools for assessing such effects, the responses of aquatic insects to WWTP effluents are poorly understood. This work investigated the responses of antioxidants (superoxide dismutase, catalase, and oxy-radical absorbance capacity), oxidative damage (lipid peroxidation), and energy reserves in caddisfly (Stenopsyche marmorata) larvae caused by the WWTP effluent in two parts of the Chikumagawa River during different seasons. It was found that effluent strongly influenced the antioxidants and oxidative damage and depleted the energy reserves. Hence, both the oxidative stress biomarkers and energy reserves in aquatic insects can be used for assessing the impacts of wastewater effluents. Lipid peroxidation proceeded more intensely at some reference sites than at the effluent-impacted sites, indicating that the use of a single biomarker could lead to a misunderstanding of the effect of pollutant mixtures in field studies. To mitigate this issue, a new reference-impacted approach based on the integrated biomarker response (IBRRI) method has been developed to assess anthropogenic impacts while considering spatiotemporal fluctuations due to the natural variations in a river system. This approach produced larger IBRRI values at higher concentrations of anthropogenic pollutants, which correlated with higher ammonium and nitrate concentrations. Therefore, IBRRI is a potentially useful tool for assessing the impact of WWTP effluents under variable spatiotemporal conditions.

Oxidative stress responses to feeding activity and salinity level in brackish water clam Corbicula japonica.

Three laboratory-scale experiments were conducted to assess the oxidative stress responses of brackish water clam Corbicula japonica to feeding activity and salinity level. Natural brackish water from Lake Hinuma was used in experiments I and II, while experiment III used artificial brackish water with cultured diatoms as the food source. During experiment I, the oxygen radical absorbance capacity (ORAC) varied greatly when the initial suspended solids (SS) concentration was 50 mg SS·L-1. As a result, no significant difference in ORAC was found between the initial SS concentrations of 5 and 50 mg SS·L-1 (p > 0.05). In contrast, during experiment II, ORAC decreased from 6.4 to 3.5 µmol Trolox Equivalent (TE)·mg protein-1 at the SS concentration of ~5 mg SS·L-1 (p < 0.05). The rate of carbon uptake in experiment I (SS concentration = 5 mg SS·L-1) was ~2.3 times greater than that in experiment II. These results indicate that SS availability has a great effect on ORAC in C. japonica. During experiment III, ORAC increased under initial SS concentrations of 0 and 40 mg SS·L-1 at salinities of 10 (p < 0.01) and 20 psu (p < 0.05), respectively. In contrast, ORAC decreased significantly decreased during the experiment for SS concentration = 80 mg SS·L-1 and salinity = 20 psu (p < 0.01) and for SS concentration = 120 mg SS·L-1 and salinity = 10 or 20 psu (p < 0.01); ATP content also decreased significantly (p < 0.01). A good correlation was found between the change in ATP content and ORAC. Together, the findings suggest that energy availability and salinity level have strong effects on antioxidant capacity in C. japonica.

Effects of water turbidity and different temperatures on oxidative stress in caddisfly (Stenopsyche marmorata) larvae.

Anthropogenic water turbidity derived from suspended solids (SS) is caused by reservoir sediment management practices such as drawdown flushing. Turbid water induces stress in many aquatic organisms, but the effects of turbidity on oxidative stress responses in aquatic insects have not yet been demonstrated. Here, we examined antioxidant responses, oxidative damage, and energy reserves in caddisfly (Stenopsyche marmorata) larvae exposed to turbid water (0 mg SS L-1, 500 mg SS L-1, and 2000 mg SS L-1) at different temperatures. We evaluated the combined effects of turbid water and temperature by measuring oxidative stress and using metabolic biomarkers. No turbidity level was significantly lethal to S. marmorata larvae. Moreover, there were no significant differences in antioxidant response or oxidative damage between the control and turbid water treatments at a low temperature (10 °C). However, at a high temperature (25 °C), turbid water modulated the activity of the antioxidant enzymes superoxide dismutase and catalase and the oxygen radical absorbance capacity as an indicator of the redox state of the insect larvae. Antioxidant defenses require energy, and high temperature was associated with low energy reserves, which might limit the capability of organisms to counteract reactive oxygen species. Moreover, co-exposure to turbid water and high temperature caused fluctuation of antioxidant defenses and increased the oxidative damage caused by the production of reactive oxygen species. Furthermore, the combined effect of high temperature and turbid water on antioxidant defenses and oxidative damage was larger than the individual effects. Therefore, our results demonstrate that exposure to both turbid water and high temperature generates additive and synergistic interactions causing oxidative stress in this aquatic insect species.

Stable silanetriols that contain tert-alkoxy groups: versatile precursors of siloxane-based nanomaterials.

Novel tert-alkoxysilanetriols (ROSi(OH)(3), R=adamantyl and 3-ethyl-3-pentyl) have been prepared from the corresponding tert-alkoxytrichlorosilanes and successfully used as molecular building blocks to produce ordered siloxane-based nanomaterials. Controlled hydrolysis of the alkoxytrichlorosilanes led to the formation of crystalline powders of alkoxysilanetriols that were stable under ambient conditions. Solid-state polycondensation of the alkoxysilanetriols occurred upon heating, which led to the formation of ordered silica-organic nanocomposites with laminated morphologies. On the other hand, silylation of the tert-alkoxysilanetriols with chlorotrimethoxysilane enabled us to synthesize well-defined oligomeric alkoxysilanes (ROSi[OSi(OMe)(3)](3)). Hydrolysis and polycondensation of these oligomers followed by acid treatment gave microporous silica with narrow pore size distributions. Thus, tert-alkoxy groups serve not only as protecting groups of siloxane species to regulate hydrolysis and polycondensation, but also as templates to generate micropores thereby providing unique synthetic pathways for the design of ordered silica-based materials.