183 research outputs found
How Should We Express Gratitude? The Effects of Method and Focus of Gratitude Expressions on the Self, the Other, and the Relationship
Two studies investigated the interpersonal and intrapersonal functions of gratitude expressions. In Study 1, participants expressed gratitude to a confederate in a lab paradigm (or expressed it privately) and consequently rated the confederate as significantly warmer and more competent. Sharing gratitude also led to a fortification of basic needs (belonging, self-esteem, meaning in life, and control). Study 2 attempted to replicate these results in addition to evaluating their own warmth and competence. Participants completed a week-long gratitude intervention that tested potential differences in the proposed two-factor model of gratitude expressions (manner of expression: private/shared, focus of gratitude: person/situation). The hypotheses that participants who share person-focused gratitude with their romantic partners will have higher satisfaction of needs and feel closer to their partner were not supported. Together, these studies create a mixed impression of gratitude’s effects. Study 2 had severe limitations due to a deviation in the data collection method due to the COVID-19 pandemic. Therefore a replication of this study should be performed, and its findings weighed carefully
Computational Study of Turbulent-Laminar Patterns in Couette Flow
Turbulent-laminar patterns near transition are simulated in plane Couette
flow using an extension of the minimal flow unit methodology. Computational
domains are of minimal size in two directions but large in the third. The long
direction can be tilted at any prescribed angle to the streamwise direction.
Three types of patterned states are found and studied: periodic, localized, and
intermittent. These correspond closely to observations in large aspect ratio
experiments.Comment: 4 pages, 5 figure
Transient growth in Taylor-Couette flow
Transient growth due to non-normality is investigated for the Taylor-Couette
problem with counter-rotating cylinders as a function of aspect ratio eta and
Reynolds number Re. For all Re < 500, transient growth is enhanced by
curvature, i.e. is greater for eta < 1 than for eta = 1, the plane Couette
limit. For fixed Re < 130 it is found that the greatest transient growth is
achieved for eta between the Taylor-Couette linear stability boundary, if it
exists, and one, while for Re > 130 the greatest transient growth is achieved
for eta on the linear stability boundary. Transient growth is shown to be
approximately 20% higher near the linear stability boundary at Re = 310, eta =
0.986 than at Re = 310, eta = 1, near the threshold observed for transition in
plane Couette flow. The energy in the optimal inputs is primarily meridional;
that in the optimal outputs is primarily azimuthal. Pseudospectra are
calculated for two contrasting cases. For large curvature, eta = 0.5, the
pseudospectra adhere more closely to the spectrum than in a narrow gap case,
eta = 0.99
The pesticide adjuvant, Toximul™, alters hepatic metabolism through effects on downstream targets of PPARα
AbstractPrevious studies demonstrated that chronic dermal exposure to the pesticide adjuvant (surfactant), Toximul™ (Tox), has significant detrimental effects on hepatic lipid metabolism. This study demonstrated that young mice dermally exposed to Tox for 12 days have significant increases in expression of peroxisomal acyl-CoA oxidase (mRNA and protein), bifunctional enzyme (mRNA) and thiolase (mRNA), as well as the P450 oxidizing enzymes Cyp4A10 and Cyp4A14 (mRNA and protein). Tox produced a similar pattern of increases in wild type adult female mice but did not induce these responses in PPARα-null mice. These data support the hypothesis that Tox, a heterogeneous blend of nonionic and anionic surfactants, modulates hepatic metabolism at least in part through activation of PPARα. Notably, all three groups of Tox-treated mice had increased relative liver weights due to significant accumulation of lipid. This could be endogenous in nature and/or a component(s) of Tox or a metabolite thereof. The ability of Tox and other hydrocarbon pollutants to induce fatty liver despite being PPARα agonists indicates a novel consequence of exposure to this class of chemicals, and may provide a new understanding of fatty liver in populations with industrial exposure
Identification of Clinically and Pathophysiologically Relevant Rheumatoid Factor Epitopes by Engineered IgG Targets
Objective: Rheumatoid factors (RFs), which are anti-IgG autoantibodies strongly associated with rheumatoid arthritis (RA), are also found in other diseases and in healthy individuals. RFs bind to various epitopes in the constant (Fc-) domain of IgG. Therefore, disease-specific reactivity patterns may exist. This study was undertaken in order to develop a new approach to dissecting RF epitope binding patterns across different diseases. Methods: We analyzed RF reactivity patterns in serum from patients with seropositive arthralgia, patients with RA, and patients with primary Sjögren’s syndrome (SS) using bioengineered, natively folded IgG-Fc targets that demonstrated selective RF binding toward several distinct regions of the IgG-Fc domain. Results: Rheumatoid factor responses primarily bound the Fc Elbow region, with a smaller number of RFs binding the Fc Tail region, while the Fc receptor binding region was hardly targeted. A restricted reactivity against the IgG-Fc Tail region was associated with less positivity for anti–citrullinated protein antibodies (ACPAs) and less arthritis development in arthralgia, whereas combined reactivity toward IgG-Fc Tail and Elbow regions was associated with more arthritis development. Reactivity toward the IgG-Fc Tail region was observed far more frequently in RA than in primary SS. Conclusion: Bioengineered IgG targets enable serologic characterization of RF reactivity patterns, and use of this approach appears to reveal patterns associated with ACPA detection and arthritis development in patients with arthralgia. These patterns are able to distinguish RA patients from primary SS patients. This new methodology improves the clinical value of RFs and our understanding of their pathophysiologic processes
Long-distance dispersal and recolonization of a fire-destroyed niche by a mite-associated fungus
The Fynbos Biome in the Core Cape Subregion of South Africa is prone to recurrent fires that
can clear vast areas of vegetation. Between periods of fire, ophiostomatoid fungi colonize the
fruiting structures of serotinous Protea species through arthropod-mediated dispersal. Using
microsatellite markers, this study considered the process whereby a Protea-associated
ophiostomatoid fungus, Knoxdaviesia proteae, recolonizes a burnt area. The genetic
diversity, composition and structure of fungal populations from young P. repens plants in a
recently burnt area were compared to populations from the adjacent, unburnt Protea
population. The only difference between K. proteae populations from the two areas was
found in the number of private alleles, which was significantly higher in the unburnt
population. The population structure, although weak, indicated that most K. proteae individuals from recently burnt areas originated from the unburnt population. However,
individuals from unsampled source populations were also detected. This, together with the
lack of isolation-by-distance across the landscape, suggested that long-distance dispersal is
important for K. proteae to recolonize burnt areas. Similarly, the high level of gene flow and
low differentiation observed between two distantly separated K. proteae populations also
supported the existence of long-distance dispersal. The genetic cohesiveness of populations
over long distances and the genetic diversity within populations could be attributed to
frequent multiple fungal migration events mediated primarily by arthropods but, potentially,
also by birds.National Research Foundation (NRF) and the Department of Science and Technology (DST)-NRF Centre of Excellence in Tree Health Biotechnology (CTHB).http://www.elsevier.com/locate/funbiohb2016Microbiology and Plant Patholog
Development of polymorphic microsatellite markers for the genetic characterisation of Knoxdaviesia proteae (Ascomycota: Microascales) using ISSR-PCR and pyrosequencing
Knoxdaviesia proteae is one of the first native
ophiostomatoid fungi discovered in South Africa, where it
consistently occurs in the infructescences of the iconic Cape
Biome plant, Protea repens. Although numerous studies have
been undertaken to better understand the ecology of
K. proteae, many questions remain to be answered, particularly
given its unique niche and association with arthropods
for dispersal.We describe the development and distribution of
microsatellite markers in K. proteae through Interspersed
Simple Sequence Repeat-Polymerase Chain Reaction (ISSR-PCR)
enrichment and pyrosequencing. A large proportion of
the 31492 sequences obtained from sequencing the enriched
genomic DNA were characterised by microsatellites
consisting of short tandem repeats and di- and tri-nucleotide
motifs. Seventeen percent of these microsatellites contained
flanking regions sufficient for primer design. Twenty-three
primer pairs were tested, of which 12 amplified and 10 generated polymorphic fragments in K. proteae. Half of these
could be transferred to the sister species, K. capensis. The
developedmarkers will be used to investigate the reproductive
system, genetic diversity and dispersal strategies of
K. proteae.National Research Foundation (NRF) and the Department of Science and Technology (DST)/NRF Centre of Excellence in Tree Health Biotechnology (CTHB).http://link.springer.com/journal/11557hb201
Folate deficiency increases the incidence of dolutegravir-associated foetal defects in a mouse pregnancy model
Background: Dolutegravir (DTG) is a recommended first-line regimen for all people with Human Immunodeficiency Virus (HIV) infection. Initial findings from Botswana, a country with no folate fortification program, showed an elevated prevalence of neural tube defects (NTDs) with peri-conceptional exposure to DTG. Here we explore whether a low folate diet influences the risk of DTG-associated foetal anomalies in a mouse model. / Methods: C57BL/6 mice fed a folate-deficient diet for 2 weeks, were mated and then randomly allocated to control (water), or 1xDTG (2.5 mg/kg), or 5xDTG (12.5 mg/kg) both administered orally with 50 mg/kg tenofovir disoproxil fumarate 33.3 mg/kg emtricitabine. Treatment was administered once daily from gestational day (GD) 0.5 to sacrifice (GD15.5). Foetuses were assessed for gross anomalies. Maternal and foetal folate levels were quantified. / Findings: 313 litters (103 control, 106 1xDTG, 104 5xDTG) were assessed. Viability, placental weight, and foetal weight did not differ between groups. NTDs were only observed in the DTG groups (litter rate: 0% control; 1.0% 1xDTG; 1.3% 5xDTG). Tail, abdominal wall, limb, craniofacial, and bleeding defects all occurred at higher rates in the DTG groups versus control. Compared with our previous findings on DTG usage in folate-replete mouse pregnancies, folate deficiency was associated with higher rates of several defects, including NTDs, but in the DTG groups only. We observed a severe left-right asymmetry phenotype that was more frequent in DTG groups than controls. / Interpretation: Maternal folate deficiency may increase the risk for DTG-associated foetal defects. Periconceptional folic acid supplementation could be considered for women with HIV taking DTG during pregnancy, particularly in countries lacking folate fortification programs. / Funding: This project has been funded by Federal funds from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, under Contract No. HHSN275201800001I and award #R01HD104553. LS is supported by a Tier 1 Canada Research Chair in Maternal-Child Health and HIV. HM is supported by a Junior Investigator award from the Ontario HIV Treatment Network
Interplay of RFX transcription factors 1, 2 and 3 in motile ciliogenesis
Cilia assembly is under strict transcriptional control during animal development. In vertebrates, a hierarchy of transcription factors (TFs) are involved in controlling the specification, differentiation and function of multiciliated epithelia. RFX TFs play key functions in the control of ciliogenesis in animals. Whereas only one RFX factor regulates ciliogenesis in C. elegans, several distinct RFX factors have been implicated in this process in vertebrates. However, a clear understanding of the specific and redundant functions of different RFX factors in ciliated cells remains lacking. Using RNA-seq and ChIP-seq approaches we identified genes regulated directly and indirectly by RFX1, RFX2 and RFX3 in mouse ependymal cells. We show that these three TFs have both redundant and specific functions in ependymal cells. Whereas RFX1, RFX2 and RFX3 occupy many shared genomic loci, only RFX2 and RFX3 play a prominent and redundant function in the control of motile ciliogenesis in mice. Our results provide a valuable list of candidate ciliary genes. They also reveal stunning differences between compensatory processes operating in vivo and ex vivo
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