Assessing the evolutionary history of the class Synurophyceae (Heterokonta) using molecular, morphometric, and paleobiological approaches

Siver, Peter A.,Jo, Bok Yeon,Kim, Jong Im,Shin, Woongghi,Lott, Anne Marie,Wolfe, Alexander P. Botanical Society of America, Inc. (Columbus) * Bu 2015 American journal of botany Vol. No.

<P>• <I>Premise of the study:</I> Heterokont algae of the class Synurophyceae, characterized by distinctive siliceous scales that cover the surface of the cell, are ecologically important in inland waters, yet their evolutionary history remains enigmatic. We explore phylogenetic relationships within this group of algae relative to geologic time, with a focus on evolution of siliceous components.</P><P>• <I>Methods:</I> We combined an expansive five-gene and time-calibrated molecular phylogeny of synurophyte algae with an extensive array of fossil specimens from the middle Eocene to infer evolutionary trends within the group.</P><P>• <I>Key results:</I> The group originated in the Jurassic approximately 157 million years ago (Ma), with the keystone genera <I>Mallomonas</I> and <I>Synura</I> diverging during the Early Cretaceous at 130 Ma. <I>Mallomonas</I> further splits into two major subclades, signaling the evolution of the V-rib believed to aid in the spacing and organization of scales on the cell covering. <I>Synura</I> also diverges into two primary subclades, separating taxa with forward-projecting spines on the scale from those with a keel positioned on the scale proper. Approximately one third of the fossil species are extinct, whereas the remaining taxa are linked to modern congeners.</P><P>• <I>Conclusions:</I> The taxonomy of synurophytes, which relies extensively on the morphology of the siliceous components, is largely congruent with molecular analyses. Scales of extinct synurophytes were significantly larger than those of modern taxa and may have played a role in their demise. In contrast, many fossil species linked to modern lineages were smaller in the middle Eocene, possibly reflecting growth in the greenhouse climatic state that characterized this geologic interval.</P>

On the Motion of the Structure Varying Multibody Systems with Two-Dimensional Dry Friction

Xie Fujie,Wolfs Peter,Cole Colin The Korean Society of Mechanical Engineers 2005 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.19 No.4

In the present paper the dynamics of the structure varying multibody systems caused by stick-slip motion with two-dimensional dry friction are analyzed. The methods to determine friction force both in stick and slip states are described. The direct method of considering the wagon bogie system as a structure varying system was used to consider two dimensional friction at the wheelset-side frame connection. The concept of friction direction angle used to determine the friction force components of two-dimensional dry friction both in the stick and slip motion states was used. A speed depended friction coefficient was used and described approximately by hyperbolic secant function. All switch conditions were derived and friction forces both for stick and slip states. Some simulation results are provided.

On the Motion of the Structure Varying Multibody Systems with Two-Dimensional Dry Friction

Fujie Xia,Peter Wolfs,Colin Cole 대한기계학회 2005 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.19 No.4

In the present paper the dynamics of the structure varying multibody systems caused by stick-slip motion with two-dimensional dry friction are analyzed. The methods to determine friction force both in stick and slip states are described. The direct method of considering the wagon bogie system as a structure varying system was used to consider two dimensional friction at the wheelset-side frame connection. The concept of friction direction angle used to determine the friction force components of two-dimensional dry friction both in the stick and slip motion states was used. A speed depended friction coefficient was used and described approximately by hyperbolic secant function. All switch conditions were derived and friction forces both for stick and slip states. Some simulation results are provided.

Haemorrhagic Transformation after Ischaemic Stroke in Patients Taking Non-vitamin K Antagonist Oral Anticoagulants

Jan C. Purrucker,Kirsten Haas,Marcel Wolf,Timolaos Rizos,Shujah Khan,Peter Kraft,Sven Poli,Rainer Dziewas,Johannes Meyne,Frederick Palm,Sebastian Jander,Markus Möhlenbruch,Peter U. Heuschmann,Roland V 대한뇌졸중학회 2017 Journal of stroke Vol.19 No.1

Background and Purpose To evaluate the frequency and outcome of haemorrhagic transformation (HT) after ischaemic stroke in patients treated with non-vitamin K antagonist oral anticoagulants (NOACs). Methods Patients with stroke on treatment with a NOAC were prospectively enrolled in this multicentre observational study between February 2012 and 2015. Brain imaging at admission and follow-up imaging until day 7 were reviewed for HT. Functional outcome was assessed by the modified Rankin scale (mRS) before the index event, at discharge, and at 3-months. Results 231 patients without recanalisation therapy (no-RT), and 32 patients with RT were eligible for analysis. Any HT was present at admission in 9/231 no-RT patients (3.9%, 95% CI 2.0 to 7.3) and in none of the patients with RT. In patients with follow-up imaging (no-RT, n=129, and RT, n=32), HT was present in 14.0% (no-RT; 95% CI, 8.9 to 21.1), and 40.6% (RT, 95% CI, 25.5 to 57.8), respectively. After adjustment for stroke severity, this difference between the no-RT and RT groups became non-significant. Symptomatic ICH was observed in 1 patient per group. HT was not associated with unfavourable outcome (mRS 3-6) at 3-months in multivariable analysis. Resumption of OAC after stroke was delayed in patients with HT compared to those without (15 d [IQR, 5–26] vs. 1 d [0–4], P<0.001). Conclusions The frequency and severity of HT after stroke on NOAC appears similar to previous reports for vitamin K antagonists and no anticoagulation. Whether asymptomatic HT should delay resumption of preventive anticoagulation requires further investigation.

Quantification of Aging-Related Decreases in Sensory Innervation of the Bladder Trigone in Rats

Mathijs M. de Rijk,Saša Peter,Amanda Wolf-Johnston,John Heesakkers,Gommert A. van Koeveringe,Lori A. Birder 대한배뇨장애요실금학회 2024 International Neurourology Journal Vol.28 No.-

Purpose: The prevalence of lower urinary tract symptoms (LUTS), characterized by problems regarding storage and/or voiding of urine, is known to significantly increase with age. Effective communication between the lower urinary tract and the central nervous system (CNS) is essential for the optimal function of this system, and heavily relies on the efficient interaction between the bladder urothelium and the afferent nerve fibers situated in close proximity to the urothelium within the lamina propria. Methods: We aimed to quantify aging-related differences in the expression of calcitonin gene-related peptide (CGRP, an established marker for sensory nerve fibers) in the trigonal mucosal layers of young (3–4 months) and aged (25–30 months) rats. We evaluated trigonal tissue from 3 animals per age group. Tissue was serially sectioned at 10 μm and stained for CGRP. Images were taken along the full length of the tissue. For each image we computed the total CGRP-positive area (μm2 ) and the median value for each animal was used for further analysis. Results: Upon statistical analysis the aged rats show a significantly lower CGRP-positive area compared to young rats (P=0.0049). These results indicate that aging has a negative effect on the area of CGRP-positive signal in the trigone. Conclusions: The structural and functional integrity of the sensory web in the trigonum of rats is negatively affected by the aging process, potentially leading to impaired communication between the bladder urothelium the CNS. Consequently, these perturbations in the sensory system may contribute to the pathogenesis or exacerbation LUTS.

Complex phylogeographic patterns in the freshwater alga <i>Synura</i> provide new insights into ubiquity vs. endemism in microbial eukaryotes

BOO, SUNG MIN,KIM, HAN SOON,SHIN, WOONGGHI,BOO, GA HUN,CHO, SUNG MI,JO, BOK YEON,KIM, JEE-HWAN,KIM, JIN HEE,YANG, EUN CHAN,SIVER, PETER A.,WOLFE, ALEXANDER P.,BHATTACHARYA, DEBASHISH,ANDERSEN, ROBERT Blackwell Publishing Ltd 2010 Molecular ecology Vol.19 No.19

<P>Abstract</P><P>The global distribution, abundance, and diversity of microscopic freshwater algae demonstrate an ability to overcome significant barriers such as dry land and oceans by exploiting a range of biotic and abiotic colonization vectors. If these vectors are considered unlimited and colonization occurs in proportion to population size, then globally ubiquitous distributions are predicted to arise. This model contrasts with observations that many freshwater microalgal taxa possess true biogeographies. Here, using a concatenated multigene data set, we study the phylogeography of the freshwater heterokont alga <I>Synura petersenii sensu lato</I>. Our results suggest that this <I>Synura</I> morphotaxon contains both cosmopolitan and regionally endemic cryptic species, co-occurring in some cases, and masked by a common ultrastructural morphology. Phylogenies based on both proteins (seven protein-coding plastid and mitochondrial genes) and DNA (nine genes including ITS and 18S rDNA) reveal pronounced biogeographic delineations within phylotypes of this cryptic species complex while retaining one clade that is globally distributed. Relaxed molecular clock calculations, constrained by fossil records, suggest that the genus <I>Synura</I> is considerably older than currently proposed. The availability of tectonically relevant geological time (10<SUP>7</SUP>–10<SUP>8</SUP> years) has enabled the development of the observed, complex biogeographic patterns. Our comprehensive analysis of freshwater algal biogeography suggests that neither ubiquity nor endemism wholly explains global patterns of microbial eukaryote distribution and that processes of dispersal remain poorly understood.</P>