Gulbas and colleagues identify a series of factors relevant to both NSSI and suicide that correspond to features we found among the SWYEPT participants, including family fragmentation, conflict, physical and sexual abuse, and domestic violence. The relationships among these factors are complex and are found cross-culturally, though they tend to be more severe with suicide than with NSSI . Logistic regressions examined differences by mid-SIP PA in likelihood of increased stress at mid-SIP and use of each stress management strategy at mid-SIP, adjusting for age, race, education, income, employment, and past-month alcohol use . Chisquare tests examined the association between mid-SIP stress and PA pattern, and between midSIP stress and mid-SIP use of stress management strategies. P-values < 0.05 were considered statistically significant. Managing stress while complying with the uniquely disruptive COVID-19 SIP restrictions may require a variety of stress management strategies. In a sample of adults mostly residing in Northern California, we examined relationships between stress, physical activity, and other stress management strategies during SIP. Participants who were physically active during SIP were less likely to feel increased stress during SIP and were more likely to report use of physically active stress management strategies. Additionally, physically active participants were less likely to report managing stress by sleeping more or eating more. Participants who reported managing stress using outdoor PA, indoor PA, and reading were less likely to feel increased stress during SIP. Those who managed stress by watching TV/movies, sleeping more, and eating more were more likely to feel increased stress. The association between greater PA and lower stress was consistent with hypotheses and with the extensive literature on the positive effects of PA on stress reduction in non-COVID contexts .

Engaging in PA may have significantly reduced stress incurred by COVID-19. Alternatively, participants with fewer stressors may have found it easier to be physically active. In this study, vertical farming systems cost participants meeting PA guidelines were older, more likely to be White and to drink alcohol, had greater educational attainment and higher household income, and were less likely to be employed . These participants may represent a subset of adults with greater resources and fewer demands on their time during SIP, leading to lower stress and increased ability to engage in PA. Nonetheless, the association between PA and stress remained statistically significant after accounting for age, race, past-month alcohol use, education, household income, and employment status. Engaging in PA may have contributed to stress management, even for participants who already had many advantages. This study suggests that the well-documented positive effects of PA on stress management persist even in the highly unusual circumstances of SIP. Active and less active participants also differed in the stress management strategies they employed. A majority of active participants reported that they used PA—especially outdoor PA — to manage stress. Active participants were four times more likely than less active participants to report managing stress using outdoor PA than inactive participants. Active participants were also more likely to report use of indoor PA, yoga, meditation, or prayer, gardening, and reading. Most of these activities involve a physical activity component. Additionally, physically active participants were less likely to cope with stress by eating more or sleeping more. Disruptions in diet are common during stressful times. Similar to the present study, a study of Belgian university students found students with more stress and less physical activity were at greatest risk for increased snacking during a stressful final exam period . COVID-19 SIP is a more widespread, disruptive, long-term stressful circumstance than a final exam period, yet similar results were found. Sleep disruptions have also been linked to stress during COVID-19 self-isolation . Indeed, in the current study, participants who managed stress by eating more, sleeping more, or watching TV/movies were more likely to report increased stress. Eating, sleeping, and watching TV/movies may have been used to manage stress by participants who were already experiencing a great deal of stress.

These activities require less energy to initiate than the more active strategies and may have felt more manageable. Concurrently, these less active strategies may have been less effective than strategies involving physical activity. Participants who coped with stress using PA or reading were less likely to report increased stress. Making PA—especially outdoor PA— more accessible during COVID-19 SIP may help ease stress. Recent changes in SIP policies in the San Francisco Bay Area have opened up local parks and activity areas . Overall level of PA during SIP, rather than change in PA, was associated with stress. Specifically, participants who became active or became less active during SIP did not significantly differ in likelihood of increased stress from those who were active throughout SIP. On the other hand, those who were less active both before and during SIP were more likely to experience increased stress. Low physical activity may be associated with other risk factors for stress, such as long work hours, that persisted during SIP. The study period was short and may not have been sufficient to show long-term associations. Other research has found that improvement in stress management over time is associated with increases in PA . As people adjust to COVID-19 and its associated restrictions, stress management and PA may improve. Although PA remained fairly consistent over the one-month study period , the proportion of participants reporting increased stress during SIP decreased substantially . Engaging in PA throughout SIP may further decrease stress. Stress management is crucial during COVID-19, as stress can increase susceptibility to viral infection . This study was observational and precludes causal conclusions about the role of PA in reducing stress. Analyses adjusted for numerous potential confounding factors; however, analyses were correlational. Generalizability of results is limited due to the non-representative sample. Most participants resided in Northern California, where the weather is generally conducive to outdoor PA year-round. The sample was predominantly middle-aged, female, White or Asian, and highly educated, with high household incomes. Although PA has near universal benefits, disparities in the ability to engage in PA during COVID-19 are likely. To our knowledge, such disparities have not yet been studied. Future research is needed to examine the role of PA in COVID-19 stress management among more socio-demographically and geographically diverse populations.

Participants were surveyed at the beginning of SIP and one month into SIP. Longer follow-up may show different patterns of results. The measure of stress used in this study was designed to capture changes in stress specific to SIP in a single item, with high face validity. Validated measures of stress, while less specific to SIP, should be used in future longitudinal research to expand upon the present study. Copper is toxic to life at levels that vary depending on the organism. Humans are mandated to not exceed 1–2 mg/L copper in their drinking water , while some freshwater animals and plants experience acute toxic effects at concentrations as low as 10 µg/L . Because the human food chain begins with plants, it is critical to understand how plants tolerate heavy metals including copper, which is frequently concentrated in soils as a result of pesticide application, sewage sludge deposition, mining, smeltering, and industrial activities. This issue is also at the crux of applying phytoremediation approaches, which use green plants to decontaminate or contain polluted soils and sediments and to purify waste waters and landfill leachates . Metal-tolerant plants inhibit incorporation of excess metal into photosynthetic tissue by restricting transport across the root endodermis and by storage in the root cortex . In contrast, hyperaccumulating plants extract metals from soils and concentrate excess amounts in harvestable parts such as leaves. Copper detoxification seems to be linked to mechanisms that bind Cu to molecular thiol groups. Cysteine-rich peptides, such as phytochelatins which transport copper to the shoot, increase in response to high cellular levels of Cu , and Cu-S binding occurs in roots and leaves of Larrea tridentata. However,vertical farming towers racks an unidentified copper species, concentrated in electron-dense granules on cell walls and some vacuole membranes, appears to be the main morphological form of copper sequestered in Oryza sativa , Cannabis sativa , Allium sativum , and Astragalus sinicus . Plants take in and exclude elements largely at the soil-root interface within the rhizosphere, i.e. the volume of soil influenced by roots, mycorrhizal fungi, and bacterial communities . Deciphering processes that control the bio-availability of metals in the field is difficult because the rhizosphere is compositionally and structurally complex. Here we report on using synchrotron-based microanalytical and imaging tools to resolve processes by which metal tolerant plants defend themselves against excess cationic copper. We have mapped the distribution of copper in self-standing thin sections of unperturbed soils using micro-Xray fluorescence and identified structural forms of copper at points-of-interest using micro-extended X-ray absorption fine structure spectroscopy and X-ray diffraction . Because only a few small areas could be analyzed in reasonable times with microanalyses, the uniqueness of the microanalytical results was tested by recording the bulk EXAFS spectrum from a sample representing the entire rhizosphere and by simulating this spectrum by linear combination of copper species spectra from POIs. We investigated copper speciation in rhizospheres of Phragmites australisand Iris pseudoacorus, two widespread wetland species with high tolerances to heavy metals .P. australisis frequently used to treat waste waters because it can store heavy metals as weakly soluble or insoluble forms. Its roots can be enriched in Cu 5-60 times relative to leaves, with large differences among ecotypes and between field-grown versus hydroponically grown plants . To take into account natural complexity, including any influence of bacteria, fungi, or climate variation, our experiment was conducted outdoors, rather than in a greenhouse on seedlings using ex-solum pots or hydroponic growth methods.

The soil was from the Pierrelaye plain, a 1200 ha truck-farming area about 30 km northwest of Paris, France. From 1899 to 1999, regular irrigation of the Pierrelaye plain with untreated sewage water from Paris caused contamination with heavy metals, mainly Zn, Pb, and Cu . Such pollution is pervasive worldwide because increasing populations and associated economic growth are diminishing available freshwater, thus leading to increased irrigation of farmlands with waste waters.In the initial soil, copper occurs in two morphological forms . One form decorates coarse organic particles that have some recognizable structures from reticular tissue , and the other occurs inThe rhizospheres were oxidizing as indicated by the presence of iron oxyhydroxide , absence of sulfide minerals, and the fact that P. australis and I. pseudoacorus are typical wetlands plants with aerenchyma that facilitate oxygen flflow from leaves to roots . Thermodynamic calculations using compositions of soil solutions collected below the rhizosphere indicate that Cu+ and Cu2+ species should have been dominant . These points along with the occurrences of nanocrystalline Cu0 in plant cortical cells and as stringer morphologies outside the roots together suggest that copper was reduced biotically. Ecosystem ecology of the rhizosphere indicates synergistic or multiple reactions by three types of organisms: plants, endomycorrhizal fungi, and bacteria. Normally, organisms maintain copper homeostasis through cation binding to bioactive molecules such as proteins and peptides. When bound, the Cu2+/Cu1+ redox couple has elevated half-cell potentials that facilitate reactions in the electron-transport chain. Even though average healthy cell environments are sufficiently reducing , there are enough binding sites to maintain copper in its two oxidized states. Copper is also important in controlling cell-damaging free radicals produced at the end of the electron-transport chain, for example in the superoxide dismutase enzyme Cu-Zn-SOD, which accelerates the disproportionation of superoxide to O2 and hydrogen peroxide. However, unbound copper ions can catalyze the decomposition of hydrogen peroxide to water and more free radical species. To combat toxic copper and free radicals, many organisms overproduce enzymes such as catalase, chelates such as glutathione, and antioxidants . Mineralization could also be a defense against toxic copper, but reports of Cu+ and Cu2+ biominerals are rare; only copper sulfide in yeast and copper oxalate in lichens and fungi are known. Atacamite 3Cl in worms does not appear to result from a biochemical defense. Biomineralization of copper metal may have occurred by a mechanism analogous to processes for metallic nanoparticle synthesis that exploit ligand properties of organic molecules. In these processes, organic molecules are used as templates to control the shape and size of metallic nanoparticles formed by adding strong reductants to bound cations. For copper nanoparticles and nanowires, a milder reductantsascorbic acidshas been used.