2,650 research outputs found
Characterisation of feline renal cortical fibroblast cultures and their transcriptional response to transforming growth factor beta 1
Chronic kidney disease (CKD) is common in geriatric cats, and the most prevalent pathology is chronic tubulointerstitial inflammation and fibrosis. The cell type predominantly responsible for the production of extra-cellular matrix in renal fibrosis is the myofibroblast, and fibroblast to myofibroblast differentiation is probably a crucial event. The cytokine TGF-β1 is reportedly the most important regulator of myofibroblastic differentiation in other species. The aim of this study was to isolate and characterise renal fibroblasts from cadaverous kidney tissue of cats with and without CKD, and to investigate the transcriptional response to TGF-β1
Explosive Nucleosynthesis: What we learned and what we still do not understand
This review touches on historical aspects, going back to the early days of
nuclear astrophysics, initiated by BFH and Cameron, discusses (i) the
required nuclear input from reaction rates and decay properties up to the
nuclear equation of state, continues (ii) with the tools to perform
nucleosynthesis calculations and (iii) early parametrized nucleosynthesis
studies, before (iv) reliable stellar models became available for the late
stages of stellar evolution. It passes then through (v) explosive environments
from core-collapse supernovae to explosive events in binary systems (including
type Ia supernovae and compact binary mergers), and finally (vi) discusses the
role of all these nucleosynthesis production sites in the evolution of
galaxies. The focus is put on the comparison of early ideas and present, very
recent, understanding.Comment: 11 pages, to appear in Springer Proceedings in Physics (Proc. of
Intl. Conf. "Nuclei in the Cosmos XV", LNGS Assergi, Italy, June 2018
Color-Octet Fraction in J/Psi Production and Absorption
The cross section between a pair and a nucleon is small and
sensitive to the separation if the pair is in a color-singlet
state, but very large and insensitive to the separation if it is in a
color-octet state. We use this property in an absorption model involving both
color components to deduce the color structure of pairs produced in
reactions. Our analysis shows that the NA3, NA38 and E772
data are not inconsistent with the theoretical picture that color-octet and
color-singlet precursors are produced in roughly equal proportions if the
produced color-singlet precursors are pointlike and transparent. However, if
the color-singlet precursors are not transparent but have a cross section of a
few mb, these data do show a definite preference for a larger fraction of
color-singlet precursors. In either case, the color-octet fraction increases
with , approaching unity as becomes large.Comment: 9 pages, updated to include new result
Tetraspanin (TSP-17) Protects Dopaminergic Neurons against 6-OHDA-Induced Neurodegeneration in <i>C. elegans</i>
Parkinson's disease (PD), the second most prevalent neurodegenerative disease after Alzheimer's disease, is linked to the gradual loss of dopaminergic neurons in the substantia nigra. Disease loci causing hereditary forms of PD are known, but most cases are attributable to a combination of genetic and environmental risk factors. Increased incidence of PD is associated with rural living and pesticide exposure, and dopaminergic neurodegeneration can be triggered by neurotoxins such as 6-hydroxydopamine (6-OHDA). In C. elegans, this drug is taken up by the presynaptic dopamine reuptake transporter (DAT-1) and causes selective death of the eight dopaminergic neurons of the adult hermaphrodite. Using a forward genetic approach to find genes that protect against 6-OHDA-mediated neurodegeneration, we identified tsp-17, which encodes a member of the tetraspanin family of membrane proteins. We show that TSP-17 is expressed in dopaminergic neurons and provide genetic, pharmacological and biochemical evidence that it inhibits DAT-1, thus leading to increased 6-OHDA uptake in tsp-17 loss-of-function mutants. TSP-17 also protects against toxicity conferred by excessive intracellular dopamine. We provide genetic and biochemical evidence that TSP-17 acts partly via the DOP-2 dopamine receptor to negatively regulate DAT-1. tsp-17 mutants also have subtle behavioral phenotypes, some of which are conferred by aberrant dopamine signaling. Incubating mutant worms in liquid medium leads to swimming-induced paralysis. In the L1 larval stage, this phenotype is linked to lethality and cannot be rescued by a dop-3 null mutant. In contrast, mild paralysis occurring in the L4 larval stage is suppressed by dop-3, suggesting defects in dopaminergic signaling. In summary, we show that TSP-17 protects against neurodegeneration and has a role in modulating behaviors linked to dopamine signaling
Parity-Violating Electron Scattering from 4He and the Strange Electric Form Factor of the Nucleon
We have measured the parity-violating electroweak asymmetry in the elastic
scattering of polarized electrons from ^4He at an average scattering angle
= 5.7 degrees and a four-momentum transfer Q^2 = 0.091 GeV^2. From
these data, for the first time, the strange electric form factor of the nucleon
G^s_E can be isolated. The measured asymmetry of A_PV = (6.72 +/- 0.84 (stat)
+/- 0.21 (syst) parts per million yields a value of G^s_E = -0.038 +/- 0.042
(stat) +/- 0.010 (syst), consistent with zero
Economic Impacts of Non-Native Forest Insects in the Continental United States
Reliable estimates of the impacts and costs of biological invasions are critical to developing credible management, trade and regulatory policies. Worldwide, forests and urban trees provide important ecosystem services as well as economic and social benefits, but are threatened by non-native insects. More than 450 non-native forest insects are established in the United States but estimates of broad-scale economic impacts associated with these species are largely unavailable. We developed a novel modeling approach that maximizes the use of available data, accounts for multiple sources of uncertainty, and provides cost estimates for three major feeding guilds of non-native forest insects. For each guild, we calculated the economic damages for five cost categories and we estimated the probability of future introductions of damaging pests. We found that costs are largely borne by homeowners and municipal governments. Wood- and phloem-boring insects are anticipated to cause the largest economic impacts by annually inducing nearly 830 million in lost residential property values. Given observations of new species, there is a 32% chance that another highly destructive borer species will invade the U.S. in the next 10 years. Our damage estimates provide a crucial but previously missing component of cost-benefit analyses to evaluate policies and management options intended to reduce species introductions. The modeling approach we developed is highly flexible and could be similarly employed to estimate damages in other countries or natural resource sectors
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