The evolving definition of plant cell type

In 1665 Robert Hooke, looking at cork through his microscope, discovered that plants are composed of elementary structures he named “cells”. Variation in the expression of a single genome in a complex eukaryotic organism guides the initiation, maturation, physiology, and biochemistry of cells with different shapes and sizes, playing different structural and functional roles in space and time. How many kinds of cells—”cell types”— an organism possesses of course depends on the organism’s cellular complexity, but the plasticity within a cell type fuels the emergence of the concept of cell state (Figure 1). The transition between cell states is driven by the developmental processes of multicellular organisms (e.g., cell determination and differentiation) and their response to environmental stresses (Wang et al., 2018). In the last decade, single cell/nucleus (sc/sn) omics, especially scRNA-seq, and spatial transcriptomics have enabled high-resolution mapping of molecular profiles of each cell, as well as mirroring cell trajectories through different states. Furthermore, unsupervised clustering of cells based on their transcriptomic (and/or epigenomic) signatures has proven effective in discovering previously unidentified cell types and cell states and providing new insight into cellular heterogeneity within a cell type (Schaum et al., 2018; Liu et al., 2021; Schumacher et al., 2021; Elmentaite et al., 2022). Classifying cells is necessary to conceptualize the biological complexity of some organs like the human brain or the plant root. But how should this be done? What criteria should be used, or, if several criteria are used, how should they be prioritized

Evolutionary Significance Of The Loss Of The Chloroplast‐Dna Inverted Repeat In The Leguminosae Subfamily Papilionoideae

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137404/1/evo05207.pd

Lyrical Music Improves 5 km Time Trial Performance Compared to Non-Lyrical Music

This study examined the effects of lyrical music compared to non-lyrical music on 5 km running performance. Thirteen subjects with an average age of 33.5 ± 8.3 years of age ran three separate 5 km time trials. The first trial acted as a familiarization trial where no music was present, followed by either a lyrical or non-lyrical music trial in a random counterbalanced order. Trial times, RPE, HR, and questionnaire information was analyzed using paired samples t-tests, ANOVA, and multivariate regression analyses. Lyrical music showed a significant improvement over non-lyrical music improving performance time compared to non-lyrical music, on average by 36 ± 41s (p=.000). While not statistically significant, a trend showing lyrical music was faster than no music, followed by the slowest trial of non-lyrical music. No change was detected in HR, or RPE at the 3.05 km mark suggesting that at the end although subjects were working harder (indicated by the faster completion times) they do not perceive themselves to be working harder. A correlation between increased mileage and the decreased effects of music as an ergogenic aid was seen (p=.044 r=.638) which supports previous research. This study suggests that lyrical music may improve 5 km running performance compared to no lyrical music

Observation of two-dimensional Fermi surface and Dirac dispersion in YbMnSb2_2

We present the crystal structure, electronic structure, and transport properties of the material YbMnSb$_2$, a candidate system for the investigation of Dirac physics in the presence of magnetic order. Our measurements reveal that this system is a low-carrier-density semimetal with a 2D Fermi surface arising from a Dirac dispersion, consistent with the predictions of density functional theory calculations of the antiferromagnetic system. The low temperature resistivity is very large, suggesting scattering in this system is highly efficient at dissipating momentum despite its Dirac-like nature.Comment: 8 pages, 6 figure

The Role of Kemeny's Constant in Properties of Markov Chains

In a finite state irreducible Markov chain with stationary probabilities \pi_i and mean first passage times m_(ij) (mean recurrence time when i = j) it was first shown by Kemeny and Snell (1960) that \sum_j \pi_j m_(ij) is a constant K, not depending on i. This constant has since become known as Kemeny's constant. A variety of techniques for finding expressions and various bounds for K are derived. The main interpretation focuses on its role as the expected time to mixing in a Markov chain. Various applications are considered including perturbation results, mixing on directed graphs and its relation to the Kirchhoff index of regular graphs.Comment: 13 page

Downhill running impairs activation and strength of the elbow flexors

PURPOSE: The aim of this study was to determine if knee extensor injury induced by 1 h of downhill running attenuated force production in uninjured skeletal muscle (e.g., elbow flexors). METHODS: Recreationally active subjects (n = 12) completed a two group (injury vs control) repeated measures design with the injury group running downhill for 1 h and the control group performing only the measurement procedures. Strength and percent voluntary muscle activation were measured using an isokinetic dynamometer and electrical stimulation of the elbow flexors and knee extensors before and after a fatigue protocol at the following time points in relation to the downhill run: 15 min pre, 15 min post, 24 h post, and 48 h post. Blood samples were collected at the same time points to measure IL-1β and TNF-α concentrations. RESULTS: Knee extensor strength was significantly reduced by 53.5±9.9% immediately post-injury and remained reduced for up to 48 h in the injury group. Elbow flexor strength was significantly reduced immediately and 24 h post-injury by 13.2±3.9% and 17.3±4.0% respectively in the injury group. Elbow flexor electrically stimulated strength was not found to be different at any time point (P = 0.561). Elbow flexor activation was significantly reduced compared to control at 24 and 48 h post-injury by 22.9±9.1% and 13.5±5.7% respectively. No differences were observed in IL-1β or TNF-α between groups. CONCLUSION: A 1 h downhill run significantly injured the knee extensors. The elbow flexor muscles remained uninjured based on electrically stimulated strength, but voluntary strength of these muscles was impaired due to reduced activation. This suggests an injury to the knee extensors can impair strength in uninjured muscles by reducing voluntary activation. The mechanism behind this reduction remains undetermined. INDEX WORDS: Downhill running, Muscle injury, Central nervous system, Inflammatio

Preclinical/subclinical rheumatoid arthritis-associated interstitial lung disease: misleading terms with potentially deleterious consequences

Interstitial lung disease (ILD) is a leading cause of mortality in patients with rheumatic diseases, including rheumatoid arthritis. The 5-year mortality rate is twice as high in patients with rheumatoid arthritis-associated ILD than in patients with rheumatoid arthritis without ILD. Moreover, a report showed that mortality rates in patients with disease codes for rheumatoid arthritis-associated ILD remained unchanged from 2005–18, even though the overall rheumatoid arthritis mortality rate declined during this time period. Despite the evidence that ILD contributes to premature death in rheumatoid arthritis, screening for ILD in patients with rheumatoid arthritis is not routinely performed in clinical practice and numerous questions remain regarding the management of rheumatoid arthritis-associated ILD

The Predictive Value of Expenses Excluded from Pro Forma Earnings

We investigate the informational properties of pro forma earnings. This increasingly popular measure of earnings excludes certain expenses that the company deems non-recurring, non-cash, or otherwise unimportant for understanding the future value of the firm. We find, however, that these expenses are far from unimportant. Higher levels of exclusions lead to predictably lower future cash flows. We also find that investors do not fully appreciate the lower cash flow implications at the time of the earnings announcement. A trading strategy based on the excluded expenses yields a large positive abnormal return in the years following the announcement, and persists after controlling for various risk factors and other anomalies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47728/1/11142_2004_Article_5127173.pd

Moringa oleifera Improves Skeletal Muscle Metabolism and Running Performance in Mice

Background: Recent estimates suggest that 7% of Americans use plant-derived nutritional supplements to treat a variety of complications and/or to improve athletic performance and skeletal muscle health. Unfortunately, these supplements are largely unregulated and understudied. For example, Moringa oleifera (M. oleifera) is a subtropical plant and is routinely used to treat inflammation, diabetes, obesity, cancer and HIV. However, the mechanism of action of M. oleifera has not been fully elucidated, thus the purpose of this study is to evaluate the role of M. oleifera as a novel ergogenic aid to improve exercise performance by driving peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α)-dependent signaling pathways implicated in mitochondrial biogenesis and oxidative metabolism in skeletal muscle tissue. Methods: Adult male C57BL/6 mice were treated with 1.0 g of M. oleifera (N = 20) per day or vehicle control (N = 20) for a total of 5 weeks. Following 3 weeks of supplementation, half of each group (RUN) was given access to running wheels every night for 2 weeks (Remaining half = SED), distances ran were recorded daily. After treatment protocols were complete, the gastrocnemius muscles were excised and assayed for known markers of mitochondrial biogenesis, angiogenesis, endurance capacity, and capillary density using immunohistochemistry and RT-PCR. Results: Our results showed a significant increase in average distance run in the M. oleifera + SED and M. oleifera + RUN groups. This physiological trend was consistent with the molecular profile of key metabolic markers, i.e., there was an increase in levels of PGC-1α, PPARγ, SDHB, SUCLG1, VEGF, PGAM-2, PGK1, and MYLPF in the M. oleifera treated groups compared to vehicle + SED. Moreover, M. oleifera also increased CSA and decreased markers of protein degradation. Conclusions: This data suggests that M. oleifera has the potential to be an ergogenic aid via enhancing energy metabolism in adult skeletal muscle by increasing the expression of key metabolic markers, including those involved in glycolysis, oxidative phosphorylation, mitochondrial biogenesis and angiogenesis