• Inconsistent social rhythms are associated with abdominal adiposity after involuntary job loss: An observational study

      Haynes, Patricia L.; Apolinar, Gabriella R.; Mayer, Candace; Kobayashi, Ume; Silva, Graciela E.; Glickenstein, David A.; Thomson, Cynthia A.; Quan, Stuart F.; Department of Health Promotion Sciences, University of Arizona; College of Nursing, University of Arizona; et al. (Wiley-Blackwell, 2020-12-28)
      Objective: Unemployment is an established risk factor for obesity. However, few studies have examined obesity-related health behavior after involuntary job loss specifically. Job loss confers a disruption in daily time structure that could lead to negative metabolic and psychological outcomes through chronobiological mechanisms. This study examines whether individuals with unstable social rhythms after involuntary job loss present with higher abdominal adiposity than individuals with more consistent social rhythms and whether this relationship varies as a function of depressive symptoms. Methods: Cross-sectional baseline data (n = 191) from the ongoing Assessing Daily Activity Patterns in occupational Transitions (ADAPT) study were analyzed using linear regression techniques. Participants completed the Social Rhythm Metric-17 (SRM) daily over 2 weeks. They also completed the Beck Depression Inventory II (BDI-II) and participated in standardized waist circumference measurements (cm). Results: A significant interaction emerged between SRM and BDI-II demonstrating that less consistent social rhythms were associated with larger waist circumference at lower levels of depressive symptoms. Additional exploratory analyses demonstrated a positive association between the number of daily activities performed alone and waist circumference when controlling for symptoms of depression. Conclusion: These findings are the first to demonstrate a relationship between social rhythm stability and abdominal adiposity in adults who have recently, involuntarily lost their jobs. Results highlight the moderating role of depressive symptoms on daily routine in studies of metabolic health. Future prospective analysis is necessary to examine causal pathways. © 2020 The Authors. Obesity Science & Practice published by World Obesity and The Obesity Society and John Wiley & Sons Ltd.
    • Nectar addition changes pollinator behavior but not plant reproduction in pollen‐rewarding Lupinus argenteus

      Heiling, Jacob M.; Bronstein, Judith L.; Irwin, Rebecca E.; Dept. of Ecology and Evolutionary Biology, University of Arizona (Wiley-Blackwell, 2021-02-19)
      PREMISE: In addition to its role as the male gamete, pollen is often used as a food reward for pollinators. Roughly 20,000 species of angiosperms are strictly pollen-rewarding, providing no other rewards to their pollinators. However, the influence of this strategy on pollinator behavior and plant reproduction is poorly understood, especially relative to the nectar-reward strategy. We performed a field experiment using the strictly pollen-rewarding Lupinus argenteus to explore how the absence of nectar influences pollinator behavior and plant reproduction. METHODS: We added artificial nectar to Lupinus argenteus individuals to simulate a phenotype that would reward pollinators with both nectar and pollen. We compared bee pollinator behavior, via direct observation, and female reproduction between nectar-added and nectarless control plants. RESULTS: Bees exhibited behavioral responses to the novel reward, collecting nectar as well as pollen and spending 27% longer per flower. Pollen transfer increased with flower visit duration. However, plants in the study population were not pollen-limited; consequently, the observed changes in pollinator behavior did not result in changes in female components of plant reproduction. CONCLUSIONS: The addition of nectar to pollen-rewarding plants resulted in modest increases in per-flower pollinator visit duration and pollen transfer, but had no effect on reproduction because, at the place and time the experiment was conducted, plants were not pollen-limited. These results suggest that a pollen-only reward strategy may allow plants that are visited by pollen foragers to minimize some costs of reproduction by eliminating investment in other rewards, such as nectar, without compromising female plant fitness. © 2021 Botanical Society of America
    • Neuroembryology.

      Darnell, Diana; Gilbert, Scott F; University of Arizona, USA (Wiley-Blackwell, 2017-01)
      How is it that some cells become neurons? And how is it that neurons become organized in the spinal cord and brain to allow us to walk and talk, to see, recall events in our lives, feel pain, keep our balance, and think? The cells that are specified to form the brain and spinal cord are originally located on the outside surface of the embryo. They loop inward to form the neural tube in a process called neurulation. Structures that are nearby send signals to the posterior neural tube to form and pattern the spinal cord so that the dorsal side receives sensory input and the ventral side sends motor signals from neurons to muscles. In the brain, stem cells near the center of the neural tube migrate out to form a mantel zone, and a set of dividing cells from the mantle zone migrate further to produce a second set of neurons at the outer surface of the brain. These neurons will form the cerebral cortex, which contains six discrete layers. Each layer has different connections and different functions. WIREs Dev Biol 2017, 6:e215. doi: 10.1002/wdev.215 For further resources related to this article, please visit the WIREs website.
    • Nitrogen acquisition strategies of mature Douglas-fir: a case study in the northern Rocky Mountains

      Qubain, C.A.; Yano, Y.; Hu, J.; School of Natural Resources and the Environment, University of Arizona (Wiley-Blackwell, 2021)
      Nitrogen (N) limits plant growth in temperate ecosystems, yet many evergreens exhibit low photosynthetic N use efficiency, which can be explained in part by their tendency to store more N than to use it in photosynthesis. However, it remains uncertain to what extent mature conifers translocate internal N reserves or take up N from soils to support new growth. In this study, we explored N dynamics within mature Douglas-fir (Pseudotsuga menziesii var. glauca) trees by linking N uptake in field-grown trees with seasonal soil available N. We used a branch-level mass balance approach to infer seasonal changes in total N among multiple needle and stem cohorts and bole tissue, and used foliar δ15N to evaluate N translocation/uptake from soils. Soil resin-exchangeable N and net N transformation rates were measured to assess whether soils had sufficient N to support new needle growth. We estimated that after bud break, new needle biomass in Douglas-fir trees accumulated an average of 0.20 ± 0.03 mg N/branch and 0.17 ± 0.03 mg N/branch in 2016 and 2017, respectively. While we did find some evidence of translocation of N from older stems to buds prior to bud break, we did not detect a significant drawdown of N from previous years’ growth during needle expansion. This suggests that the majority of N used for new growth was not reallocated from aboveground storage, but originated from the soils. This finding was further supported by the δ15N data, which showed divergent δ15N patterns between older needles and buds prior to leaf flushing (indicative of translocation), but similar patterns of depletion and subsequent enrichment following leaf expansion (indicative of N originating from soils). Overall, in order to support new growth, our study trees obtained the majority of N from the soils, suggesting tight coupling between soil available N and N uptake in the ecosystem. © 2021 The Authors.
    • Persistent mitral regurgitation after left ventricular assist device: a clinical conundrum

      Cruz Rodriguez, Jose B.; Chatterjee, Arka; Pamboukian, Salpy V.; Tallaj, Jose A.; Joly, Joanna; Lenneman, Andrew; Aryal, Sudeep; Hoopes, Charles W.; Acharya, Deepak; Rajapreyar, Indranee; et al. (Wiley-Blackwell, 2021-01-20)
      Aims: Persistent mitral valve regurgitation (MR) after continuous flow left ventricular assist device implantation (cfLVAD) is associated with pulmonary hypertension and right ventricular failure with variable effects on survival across published studies. The aim of this study is to determine the incidence and predictors of persistent MR at 6-month follow-up after cfLVAD implantation and its impact on survival, haemodynamics, right ventricular function, and morbidity. Methods and results: We performed a retrospective review of all adult cfLVAD recipients from January 2012 to June 2017 at a single tertiary university hospital with follow-up until April 2019. Primary outcome was to compare survival between patients with no-to-mild compared with persistent moderate-to-severe MR at 6 months. Secondary outcomes included right heart failure (RHF), length of stay, re-hospitalizations, and composite of death, transplant, and pump exchange during the length of follow-up. Final analytic sample was 111 patients. The incidence of persistent moderate or severe MR at 6 months was 26%. Significant predictors of persistent MR at 6 months were left atrium dimension and volume. The group with persistent moderate-to-severe MR at 6 months had higher incidence of RHF at 6 months (45% vs. 25%, P = 0.04). There was no difference in survival at 1 year between the groups (no-to-mild MR 85.5%, moderate-to-severe MR 87.9%, Wilcoxon P-value = 0.63). There was no difference in re-hospitalizations, length of stay, composite of death, transplant, or pump exchange during the length of follow-up between the comparison groups. Conclusions: Persistent moderate-to-severe MR after cfLVAD implantation is present in one fourth of patients and is associated with increased incidence of RHF, higher mean pulmonary pressure, and pulmonary capillary wedge pressure with no effect on 1 year survival. Increased left atrium size was associated with persistent moderate-to-severe MR at 6 months.
    • Vitamin D deficiency is associated with chronic obstructive pulmonary disease and exacerbation of COPD

      Lokesh, Komarla Sundararaja; Chaya, Sindaghatta Krishnarao; Jayaraj, Biligere Siddaiah; Praveena, Attahalli Shivanarayanprasad; Krishna, Murali; Madhivanan, Purnima; Mahesh, Padukudru Anand; Department of Health Promotion Sciences, Mel & Enid Zuckerman College of Public Health, University of Arizona; Division of Infectious Diseases, College of Medicine, University of Arizona (Wiley-Blackwell, 2020-11-20)
      Introduction: Low Vitamin D levels have been associated with Chronic Obstructive Pulmonary Disease (COPD) and acute exacerbations. Objectives: There is a paucity of data on Vitamin D and COPD, its severity and exacerbations in populations that are exposed to sunlight regularly with high levels of physical activity most of their lives. Methods: Serum levels of 25-OH-Vitamin-D were assessed in 100 COPD subjects and 100 age- and gender-matched controls from the rural community-based MUDHRA cohort in South India. Levels of <20 ng/mL were defined as Vitamin D deficiency. Smoking habits, occupation, Charlson co-morbidity index, Standard of living index(SLI), body mass index(BMI), 6-minute walking distance were examined for associations with logistic regression between controls and COPD subjects. Unconditional logistic regression was used to examine the association with exacerbation of COPD. Results: Vitamin D deficiency was observed in 64.5% (95%CI 57.7–70.8) of the subjects in spite of regular exposure to sunlight. Subjects with COPD had higher risk of Vitamin D deficiency (Adjusted OR: 5.05; 95%CI 1.4–17.8) as compared to controls. Amongst subjects with COPD, Vitamin D deficient subjects were three times more likely to have exacerbations in the previous year (Adjusted OR:3.51; 95%CI 1.27–9.67) as compared to COPD subjects without Vitamin D deficiency. Levels of Vitamin D <20.81 ng/mL and <18.45 ng/mL had the highest levels of combined sensitivity and specificity for COPD and acute exacerbation of COPD (AECOPD) respectively. Conclusion: In a rural population exposed to sunlight many hours a day throughout their lives, low Vitamin D levels were associated with COPD and exacerbations of COPD. © 2020 John Wiley & Sons Ltd.