Showing papers by "Miami University published in 2021"

Widespread deoxygenation of temperate lakes

Abstract: The concentration of dissolved oxygen in aquatic systems helps to regulate biodiversity1,2, nutrient biogeochemistry3, greenhouse gas emissions4, and the quality of drinking water5. The long-term declines in dissolved oxygen concentrations in coastal and ocean waters have been linked to climate warming and human activity6,7, but little is known about the changes in dissolved oxygen concentrations in lakes. Although the solubility of dissolved oxygen decreases with increasing water temperatures, long-term lake trajectories are difficult to predict. Oxygen losses in warming lakes may be amplified by enhanced decomposition and stronger thermal stratification8,9 or oxygen may increase as a result of enhanced primary production10. Here we analyse a combined total of 45,148 dissolved oxygen and temperature profiles and calculate trends for 393 temperate lakes that span 1941 to 2017. We find that a decline in dissolved oxygen is widespread in surface and deep-water habitats. The decline in surface waters is primarily associated with reduced solubility under warmer water temperatures, although dissolved oxygen in surface waters increased in a subset of highly productive warming lakes, probably owing to increasing production of phytoplankton. By contrast, the decline in deep waters is associated with stronger thermal stratification and loss of water clarity, but not with changes in gas solubility. Our results suggest that climate change and declining water clarity have altered the physical and chemical environment of lakes. Declines in dissolved oxygen in freshwater are 2.75 to 9.3 times greater than observed in the world’s oceans6,7 and could threaten essential lake ecosystem services2,3,5,11. Analysis of temperate lakes finds a widespread decline in dissolved oxygen concentrations in surface and deep waters, which is associated with reduced solubility at warmer surface water temperatures and increased stratification at depth.

Repurposing approved drugs as inhibitors of SARS-CoV-2 S-protein from molecular modeling and virtual screening.

Abstract: Herein, molecular modeling techniques were used with the main goal to obtain candidates from a drug database as potential targets to be used against SARS-CoV-2. This novel coronavirus, responsible ...

Hydrogel-based biocontainment of bacteria for continuous sensing and computation.

Abstract: Genetically modified microorganisms (GMMs) can enable a wide range of important applications including environmental sensing and responsive engineered living materials. However, containment of GMMs to prevent environmental escape and satisfy regulatory requirements is a bottleneck for real-world use. While current biochemical strategies restrict unwanted growth of GMMs in the environment, there is a need for deployable physical containment technologies to achieve redundant, multi-layered and robust containment. We developed a hydrogel-based encapsulation system that incorporates a biocompatible multilayer tough shell and an alginate-based core. This deployable physical containment strategy (DEPCOS) allows no detectable GMM escape, bacteria to be protected against environmental insults including antibiotics and low pH, controllable lifespan and easy retrieval of genomically recoded bacteria. To highlight the versatility of DEPCOS, we demonstrated that robustly encapsulated cells can execute useful functions, including performing cell-cell communication with other encapsulated bacteria and sensing heavy metals in water samples from the Charles River.

A comparison of RAFT and ATRP methods for controlled radical polymerization

Abstract: Reversible addition–fragmentation chain-transfer (RAFT) polymerization and atom transfer radical polymerization (ATRP) are the two most common controlled radical polymerization methods. Both methods afford functional polymers with a predefined length, composition, dispersity and end group. Further, RAFT and ATRP tame radicals by reversibly converting active polymeric radicals into dormant chains. However, the mechanisms by which the ATRP and RAFT methods control chain growth are distinct, so each method presents unique opportunities and challenges, depending on the desired application. This Perspective compares RAFT and ATRP by identifying their mechanistic strengths and weaknesses, and their latest synthetic applications. Reversible addition–fragmentation chain-transfer (RAFT) polymerization and atom transfer radical polymerization (ATRP) are evaluated in terms of their mechanistic strengths and weaknesses, versatility and latest synthetic advances.

PET-RAFT Polymerization: Mechanistic Perspectives for Future Materials

Abstract: In the past decade, photochemistry has emerged as a growing area in organic and polymer chemistry. Use of light to drive polymerization has advantages by imparting spatial and temporal control over...

Returning to a Normal Life via COVID-19 Vaccines in the United States: A Large-scale Agent-Based Simulation Study.

Abstract: Background: In 2020, COVID-19 has claimed more than 300,000 deaths in the United States alone. Although nonpharmaceutical interventions were implemented by federal and state governments in the United States, these efforts have failed to contain the virus. Following the Food and Drug Administration's approval of two COVID-19 vaccines, however, the hope for the return to normalcy has been renewed. This hope rests on an unprecedented nationwide vaccine campaign, which faces many logistical challenges and is also contingent on several factors whose values are currently unknown. Objective: We study the effectiveness of a nationwide vaccine campaign in response to different vaccine efficacies, the willingness of the population to be vaccinated, and the daily vaccine capacity under two different federal plans. To characterize the possible outcomes most accurately, we also account for the interactions between nonpharmaceutical interventions and vaccines through 6 scenarios that capture a range of possible impacts from nonpharmaceutical interventions. Methods: We used large-scale, cloud-based, agent-based simulations by implementing the vaccination campaign using COVASIM, an open-source agent-based model for COVID-19 that has been used in several peer-reviewed studies and accounts for individual heterogeneity and a multiplicity of contact networks. Several modifications to the parameters and simulation logic were made to better align the model with current evidence. We chose 6 nonpharmaceutical intervention scenarios and applied the vaccination intervention following both the plan proposed by Operation Warp Speed (former Trump administration) and the plan of one million vaccines per day, proposed by the Biden administration. We accounted for unknowns in vaccine efficacies and levels of population compliance by varying both parameters. For each experiment, the cumulative infection growth was fitted to a logistic growth model, and the carrying capacities and the growth rates were recorded. Results: For both vaccination plans and all nonpharmaceutical intervention scenarios, the presence of the vaccine intervention considerably lowers the total number of infections when life returns to normal, even when the population compliance to vaccines is as low as 20%. We noted an unintended consequence; given the vaccine availability estimates under both federal plans and the focus on vaccinating individuals by age categories, a significant reduction in nonpharmaceutical interventions results in a counterintuitive situation in which higher vaccine compliance then leads to more total infections. Conclusions: Although potent, vaccines alone cannot effectively end the pandemic given the current availability estimates and the adopted vaccination strategy. Nonpharmaceutical interventions need to continue and be enforced to ensure high compliance so that the rate of immunity established by vaccination outpaces that induced by infections.

Climate change drives widespread shifts in lake thermal habitat

Abstract: Lake surfaces are warming worldwide, raising concerns about lake organism responses to thermal habitat changes. Species may cope with temperature increases by shifting their seasonality or their depth to track suitable thermal habitats, but these responses may be constrained by ecological interactions, life histories or limiting resources. Here we use 32 million temperature measurements from 139 lakes to quantify thermal habitat change (percentage of non-overlap) and assess how this change is exacerbated by potential habitat constraints. Long-term temperature change resulted in an average 6.2% non-overlap between thermal habitats in baseline (1978–1995) and recent (1996–2013) time periods, with non-overlap increasing to 19.4% on average when habitats were restricted by season and depth. Tropical lakes exhibited substantially higher thermal non-overlap compared with lakes at other latitudes. Lakes with high thermal habitat change coincided with those having numerous endemic species, suggesting that conservation actions should consider thermal habitat change to preserve lake biodiversity.

Automatically Assessing Code Understandability

Abstract: Understanding software is an inherent requirement for many maintenance and evolution tasks. Without a thorough understanding of the code, developers would not be able to fix bugs or add new features timely. Measuring code understandability might be useful to guide developers in writing better code, and could also help in estimating the effort required to modify code components. Unfortunately, there are no metrics designed to assess the understandability of code snippets. In this work, we perform an extensive evaluation of 121 existing as well as new code-related, documentation-related, and developer-related metrics. We try to (i) correlate each metric with understandability and (ii) build models combining metrics to assess understandability. To do this, we use 444 human evaluations from 63 developers and we obtained a bold negative result : none of the 121 experimented metrics is able to capture code understandability, not even the ones assumed to assess quality attributes apparently related, such as code readability and complexity. While we observed some improvements while combining metrics in models, their effectiveness is still far from making them suitable for practical applications. Finally, we conducted interviews with five professional developers to understand the factors that influence their ability to understand code snippets, aiming at identifying possible new metrics.

Potential health benefits of edible insects

Abstract: Animal-based foods have traditionally been viewed as dietary staples because they provide many essential nutrients; however, edible insects have the potential to serve as healthy, sustainable alternatives to these because of their nutrient contents. Edible insects may have superior health benefits due to their high levels of vitamin B12, iron, zinc, fiber, essential amino acids, omega-3 and omega-6 fatty acids, and antioxidants. The addition of edible insects such as crickets to the human diet could offer a myriad of environmental and nutritional benefits including an overall reduction in greenhouse gas emissions, decreased agricultural use of land and water, improved prevention and management of chronic diseases like diabetes, cancer, and cardiovascular disease, and enhanced immune function. Future research should aim to understand the beneficial effects of whole insects or insect isolates in comparison to traditional animal- and plant-based foodstuffs. Ultimately, insects have the potential to be used as meat substitutes or dietary supplements, resulting in human health and environmental benefits. The purpose of this review is to provide additional insight on the nutrient composition of edible insects, their potential use as meat substitutes or dietary supplements, the associated health and wellness benefits, and their potential role in exercise performance.

Disparities in telehealth utilization during the COVID-19 pandemic: Findings from a nationally representative survey in the United States.

Abstract: Telehealth is an important source of health care during the COVID-19 pandemic. Evidence is scarce regarding disparities in telehealth utilization in the United States. We aimed to investigate the prevalence and factors associated with telehealth utilization among US adults. Our data came from the Health, Ethnicity, and Pandemic Study, a nationally representative survey conducted in October 2020, with 2554 adults ≥ 18 and an oversample of racial/ethnic minorities. Telehealth utilization was measured as self-reported teleconsultation with providers via email, text message, phone, video, and remote patient monitoring during the pandemic. Logistic regressions were performed to examine the association between telehealth use and factors at the individual, household, and community levels. Overall, 43% of the sample reported having used telehealth, representing 114.5 million adults in the nation. East and Southeast Asians used telehealth less than non-Hispanic Whites (OR = 0.5, 95% CI: 0.3-0.8). Being uninsured (compared with private insurance: OR = 0.4, 95% CI: 0.2-0.8), and those with limited broadband coverage in the community (OR = 0.5, 95% CI: 0.3-0.8) were less likely to use telehealth. There is a need to develop and implement more equitable policies and interventions at both the individual and community levels to improve access to telehealth services and reduce related disparities.

Changes of Exercise, Screen Time, Fast Food Consumption, Alcohol, and Cigarette Smoking during the COVID-19 Pandemic among Adults in the United States.

Abstract: Objective: To investigate the impact of the COVID-19 pandemic on multiple lifestyle changes among adults in the United States (USA). Methods: We conducted a survey, the Health, Ethnicity, and Pandemic (HEAP) Study, in October 2020 among USA adults. Participants were selected from the United States using 48 sampling strata, including age, race, ethnicity, education, and gender, and were asked to report five lifestyle behaviors (i.e., exercise time, screen time, fast-food meal consumption, alcohol drinking, and cigarette smoking) before and during the COVID-19 pandemic. The associations of sociodemographic factors with each lifestyle change were estimated using weighted multivariable logistic regression models. Results: All 2709 HEAP participants were included in this study. Compared to pre-pandemic, the time spent on exercise decreased (32.06 vs. 38.65 min/day; p < 0.001) and screen time increased (6.79 vs. 5.06 h/day; p < 0.001) during the pandemic. The percentage of individuals who reported consuming fast-food meals ≥3 times/week decreased from 37.7% before the pandemic to 33.3% during the pandemic. The percentage of heavy drinkers (≥5 times/week) increased from 20.9% before the pandemic to 25.7% during the pandemic. Among smokers, heavy smoking (≥11 cigarettes/day) increased from 5.8% before the pandemic to 7.9% during the pandemic. We also identified subgroups who were more vulnerable to adverse influences from the pandemic, including racial/ethnic minority groups and young adults. Conclusions: The COVID-19 pandemic had negative impacts on multiple lifestyle behaviors among Americans. Mitigating such negative impacts of COVID-19 requires effective interventions, particularly for some vulnerable subgroups.

The Transient Covalent Bond in Abiotic Nonequilibrium Systems

Abstract: Biochemical systems accomplish many critical functions with by operating out-of-equilibrium using the energy of chemical fuels. The formation of a transient covalent bond is a simple but very effective tool in designing analogous reaction networks. This Minireview focuses on the fuel chemistries that have been used to generate transient bonds in recent demonstrations of abiotic nonequilibrium systems (i.e., systems that do not make use of biological components). Fuel reactions are divided into two fundamental classifications depending on whether the fuel contributes structural elements to the activated state, a distinction that dictates how they can be used. Reported systems are further categorized by overall fuel reaction (e.g., hydrolysis of alkylating agents, carbodiimide hydration) and illustrate how similar chemistry can be used to effect a wide range of nonequilibrium behavior, ranging from self-assembly to the operation of molecular machines.

A Common Grounded Type Dual-Mode Five-Level Transformerless Inverter for Photovoltaic Applications

Abstract: This article presents a novel dual-mode five-level common grounded type (5L-DM-CGT) transformerless inverter topology for a medium-power application with a wide input voltage range (200–400 V). It consists of nine semiconductor switches, two inner flying-capacitors, and a small LC filter at the output side. Due to the direct connection of the negative terminal of the photovoltaic to the neutral point of the grid, there is no leakage current in the 5L-DM-CGT. Depending on the magnitude of the input voltage, the converter can operate in both buck and boost mode to produce the same ac output voltage. The theoretical analysis shows the advantages of the dual-mode inverter for various industrial applications. Finally, the laboratory test results are presented to verify the theoretical analysis. Measurement results show that the proposed inverter rated at 1 kW has around 97±1% efficiency over a wide range of load with a peak efficiency of 98.96% at 130 VA in buck mode and peak efficiency of 99% at 122 VA in boost mode.

Life stress and cortisol reactivity: An exploratory analysis of the effects of stress exposure across life on HPA-axis functioning.

Abstract: Stressful experiences affect biological stress systems, such as the hypothalamic–pituitary–adrenal (HPA) axis. Life stress can potentially alter regulation of the HPA axis and has been associated with poorer physical and mental health. Little, however, is known about the relative influence of stressors that are encountered at different developmental periods on acute stress reactions in adulthood. In this study, we explored three models of the influence of stress exposure on cortisol reactivity to a modified version of the Trier Social Stress Test (TSST) by leveraging 37 years of longitudinal data in a high-risk birth cohort (N = 112). The cumulative stress model suggests that accumulated stress across the lifespan leads to dysregulated reactivity, whereas the biological embedding model implicates early childhood as a critical period. The sensitization model assumes that dysregulation should only occur when stress is high in both early childhood and concurrently. All of the models predicted altered reactivity, but do not anticipate its exact form. We found support for both cumulative and biological embedding effects. However, when pitted against each other, early life stress predicted more blunted cortisol responses at age 37 over and above cumulative life stress. Additional analyses revealed that stress exposure in middle childhood also predicted more blunted cortisol reactivity.

Visualization and Quantification of Electrochemical H2 Bubble Nucleation at Pt, Au, and MoS2 Substrates.

Abstract: Electrolytic gas evolution is a significant phenomenon in many electrochemical technologies from water splitting, chloralkali process to fuel cells. Although it is known that gas evolution may subs...

Recent Perspectives on Sex Differences in Compulsion-Like and Binge Alcohol Drinking.

Abstract: Alcohol use disorder remains a substantial social, health, and economic problem and problem drinking levels in women have been increasing in recent years Understanding whether and how the underlying mechanisms that drive drinking vary by sex is critical and could provide novel, more targeted therapeutic treatments Here, we examine recent results from our laboratories and others which we believe provide useful insights into similarities and differences in alcohol drinking patterns across the sexes Findings for binge intake and aversion-resistant, compulsion-like alcohol drinking are considered, since both are likely significant contributors to alcohol problems in humans We also describe studies regarding mechanisms that may underlie sex differences in maladaptive alcohol drinking, with some focus on the importance of nucleus accumbens (NAcb) core and shell regions, several receptor types (dopamine, orexin, AMPA-type glutamate), and possible contributions of sex hormones Finally, we discuss how stressors such as early life stress and anxiety-like states may interact with sex differences to contribute to alcohol drinking Together, these findings underscore the importance and critical relevance of studying female and male mechanisms for alcohol and co-morbid conditions to gain a true and clinically useful understanding of addiction and neuropsychiatric mechanisms and treatment

Monitoring worker fatigue using wearable devices: A case study to detect changes in gait parameters

Abstract: The goal of this case study is to answer four research questions related to fatigue through features derived from wearable sensors to measure patterns in steps: (1) How do important gait parameters...

When will Black children be well? Interrupting anti-Black violence in early childhood classrooms and schools:

Abstract: We demonstrate that Black children are not faring well in early childhood settings and suggest ways educators can work toward ensuring that Black children thrive and flourish in schools. Five types...

Comparing the clinical presentation of eating disorder patients with and without trauma history and/or comorbid PTSD.

Abstract: This study examined whether clinical characteristics among patients presenting to residential eating disorder (ED) treatment differed according to patients’ trauma history and current PTSD diagnost...

Vitrimer Transition Temperature Identification: Coupling Various Thermomechanical Methodologies

Abstract: Vitrimers hold great promise as adaptive materials capable of shape reconfigurability, welding, and self-healing due to dynamic covalent reactions occurring above the vitrimer transition temperatur...

3D-Printed Self-Healing Elastomers for Modular Soft Robotics.

Abstract: Advances in materials, designs, and controls are propelling the field of soft robotics at an incredible rate; however, current methods for prototyping soft robots remain cumbersome and struggle to incorporate desirable geometric complexity. Herein, a vat photopolymerizable self-healing elastomer system capable of extreme elongations up to 1000% is presented. The material is formed from a combination of thiol/acrylate mixed chain/step-growth polymerizations and uses a combination of physical processes and dynamic-bond exchange via thioethers to achieve full self-healing capacity over multiple damage/healing cycles. These elastomers can be three dimensional (3D) printed with modular designs capable of healing together to form highly complex and large functional soft robots. Additionally, these materials show reprogrammable resting shapes and compatibility with self-healing liquid metal electronics. Using these capabilities, subcomponents with multiple internal channel systems were printed, healed together, and combined with functional liquid metals to form a high-wattage pneumatic switch and a humanoid-scale soft robotic gripper. The combination of 3D printing and self-healing elastomeric materials allows for facile production of support-free parts with extreme complexity, resulting in a paradigm shift for the construction of modular soft robotics.

Disordered eating, self-esteem, and depression symptoms in Iranian adolescents and young adults: A network analysis.

Abstract: Objective The network theory of psychopathology examines networks of interconnections across symptoms. Several network studies of disordered eating have identified central and bridge symptoms in Western samples, yet network models of disordered eating have not been tested in non-Western samples. The current study tested a network model of disordered eating in Iranian adolescents and college students, as well as models of co-occurring depression and self-esteem. Method Participants were Iranian college students (n= 637) and adolescents (n = 1,111) who completed the Eating Disorder Examination-Questionnaire (EDE-Q), Rosenberg Self-Esteem Scale (RSES) and Beck Depression Inventory, Second Edition (BDI-II). We computed six Glasso networks and identified central and bridge symptoms. Results Central disordered eating nodes in most models were a desire to lose weight and discomfort when seeing one's own body. Central self-esteem and depression nodes were feeling useless and self-dislike, respectively. Feeling like a failure was the most common bridge symptom between disordered eating and depression symptoms. With exception of a few differences in some edges, networks did not significantly differ in structure. Discussion Desire to lose weight was the most central node in the networks, which is consistent with sociocultural theories of disordered eating development, as well as prior network models from Western-culture samples. Feeling like a failure was the most central bridge symptom between depression and disordered eating, suggesting that very low self-esteem may be a shared correlate or risk factor for disordered eating and depression in Iranian adolescents and young adults.