bluuebunny/crossref_metadata_2025_split huggingface dataset:
Startle modulation and explicit valence evaluations dissociate during backward fear conditioning
Authors: Luck Camilla C. , Lipp Ottmar V. 
Published: February 2017

AbstractBlink startle magnitude is linearly modulated by affect such that, relative to neutral stimuli, startle magnitude is inhibited during pleasant stimuli and potentiated during unpleasant stimuli. Andreatta, Mühlberger, Yarali, Gerber, and Pauli (2010), however, report a dissociation between startle modulation and explicit valence evaluations during backward conditioning, a procedure in which the unconditional stimulus precedes the conditional stimulus (CS). Relative to controls, startles elicited during the CS were inhibited, suggesting that the CS had acquired positive valence, but participants still evaluated the CS as unpleasant after the experiment. In Experiment 1, we aimed to replicate this dissociation using a trial‐by‐trial measure of CS valence to measure startle modulation and CS valence simultaneously during forward and backward differential fear conditioning. In Experiment 2, we examined whether early and late portions of the CS could acquire differential valence by presenting startle probes at early and late probe positions during the CS. In both experiments, the dissociation between startle modulation and explicit valence evaluations in backward conditioning replicated, with CS+ evaluated as less pleasant than CS‐, but startles elicited during CS+ inhibited relative to CS‐. In Experiment 2, we provide preliminary evidence that this inhibition was present early, but not late, during the CS+. The results replicate the dissociation between implicit and explicit CS valence reported by Andreatta et al. (2010) using a trial‐by‐trial measure of valence. We also provide preliminary evidence that this dissociation may occur because the implicit and explicit measures are recorded at different times during the CS presentation.
Joint Regression Analysis of Marginal Quantile and Quantile Association: Application to Longitudinal Body Mass Index in Adolescents
Authors: Yang Chi-Chuan , Chen Yi-Hau , Chang Hsing-Yi 
Published: February 2017

SummaryThe paper proposes joint regression analysis of the marginal quantiles of longitudinal or clustered outcomes as well as the association between pairs of the outcomes, with the association measuring the tendency of concordance between pairs of the outcomes with respect to their marginal quantiles. The motivation comes from a longitudinal adolescent body mass index (BMI) study where both the marginal quantile regression of BMI and the tendency that an adolescent with BMI higher than the 75th population quantile of the BMI at some age would still have BMI higher than the 75th population quantile of the BMI at some later age are of interest. The new procedure generalizes the ‘alternative logistic regressions’ to marginal quantile regression and extends the ‘quantile association regression’ to general analysis of longitudinal and clustered data. A novel bivariate induced smoothing technique is proposed for stable and efficient computation. The application to the longitudinal adolescent BMI study reveals the practical utility of our proposal.
Comparison of pro‐inflammatory cytokines of non‐healing and healing cutaneous leishmaniasis
Authors: Moafi M. , Rezvan H. , Sherkat R. , Taleban R. , Asilian A. , Hamid Zarkesh‐Esfahani S. , Nilforoushzadeh M. A. , Jaffary F. , Mansourian M. , Sokhanvari F. , Ansari N. 
Published: February 2017

AbstractCutaneous leishmaniasis (CL) heals spontaneously within several weeks or months, but, in rare cases, CL‐active lesions last for many years. In this study, we assessed cell‐mediated immunity in non‐healing CL through the measurement of three pro‐inflammatory cytokines: Interferon‐γ (IFN‐γ), IL‐17a and CXCL‐11. For this, 32 patients afflicted with healing or non‐healing CL were recruited in this study. Peripheral blood mononuclear cells (PBMCs) of every patient were treated with three antigens: purified protein derivative (PPD), soluble Leishmania antigen (SLA) and phytohaemagglutinin (PHA). Cytokine quantification was performed using enzyme‐linked immunosorbent assay (ELISA) method. Results of our study showed that neither cytokine produced in the presence of a PPD stimulator (as an irrelevant antigen) significantly differed between the healing and non‐healing groups (P‐value ≥0.05 for all of them). However, IFN‐γ, CXCL‐11 and IL‐17a levels produced in the presence of PHA or SLA were significantly higher within the healing than in the non‐healing group (P‐value <0.01 for all of them). It seems that appropriate levels of IFN‐γ, as well as IL‐17a and CXCL‐11, contribute to the control of Leishmania infection.
The sociology of antiracism in Black and White
Authors: Brown Melissa 
Published: February 2017

AbstractThis paper reviews sociological research on antiracism and suggests new directions for the field. Current research indicates although White antiracism constitutes attempts to negotiate privilege, it fails to divest from the systems of power that maintain the current balance of privilege in favor of White supremacy. In contrast, the antiracism of people of color provides some insight into attempts to secure liberation, a complete break from White supremacist power structures. I argue DuBois, Black Feminist Thought, and postcolonial sociology inform a sociology of antiracism that centers people of color rather than Whiteness. To illustrate the nuance of antiracism by people of color, I centered my study on Black antiracism. From this perspective, antiracism emerges as the set of practices that Blacks enact in everyday life to mitigate and confront hegemonic racialization. I suggest that one construct ofhegemonic whitenessmeant to uphold dominant racial ideology that producesemphasized blacknessthat facilitates symbolic and physical violence toward Blacks. Althoughemphasized blacknessproduces and reinforces constraints on Black antiracism,oppositional blacknessexemplifies an ultimate form of antiracism in which Black bodies act as agents of social change through liberatory projects such as marronage and counterhegemonic knowledge production. I conclude this article with a case study of the Windward Maroons of Jamaica to illustrateoppositional blacknessas the dynamics of resistance and empowerment that emerge to confront hegemonic whiteness.
Optimal strategies for the diagnosis of community‐onset diarrhea in solid organ transplant recipients: Less is more
Authors: Trinh Sonya A. , Echenique Ignacio A. , Penugonda Sudhir , Angarone Michael P. 
Published: February 2017

AbstractBackgroundDiarrhea, a common complication after solid organ transplant (SOT), is associated with allograft failure and death. No evidence‐based guidelines exist for the evaluation of diarrhea in SOT recipients. We performed a cost analysis to derive a testing algorithm for the diagnosis of community‐onset diarrhea that minimizes costs without compromising diagnostic yields.DesignA cost analysis was performed on a retrospective cohort of 422 SOT admissions for community‐onset diarrhea over an 18‐month period. A stepwise testing model was applied on a population level to assess test costs relative to diagnostic yields.ResultsOver an 18‐month period, 1564 diagnostic tests were performed and 127 (8.1%) returned positive. Diagnostic testing accounted for $95 625 of hospital costs. The tests with the lowest cost per decrease in the false‐omission rate (FOR) were stool Clostridium difficile polymerase chain reaction (PCR) ($156), serum cytomegalovirus quantitative PCR ($1529), stool norovirus (NV) PCR ($4673), and stool culture ($6804). A time‐to‐event analysis found no significant difference in the length of hospital stay between patients with and without NV testing (P=.520).ConclusionsA stepwise testing strategy can reduce costs without compromising diagnostic yields. In the first‐stage testing, we recommend assessment for C. difficile, cytomegalovirus, and food‐borne bacterial pathogens. For persistent diarrheal episodes, second‐stage evaluation should include stool NV PCR, Giardia/Cryptosporidium enzyme immunoassay, stool ova and parasite, reductions in immunosuppressive therapy, and possibly endoscopy. Although NV testing had a relatively low cost per FOR, we recommend NV testing during second‐stage evaluation, as an NV diagnosis may not lead to changes in clinical management or further reductions in length of hospital stay.
Predictive Factors for Fatal Tick‐Borne Spotted Fever in Brazil
Authors: de Oliveira S. V. , Willemann M. C. A. , Gazeta G. S. , Angerami R. N. , Gurgel‐Gonçalves R. 
Published: February 2017

SummaryIn Brazil, two pathogenic Rickettsia species have been identified causing tick‐borne spotted fever (SF). The aetiological agent Rickettsia rickettsii causes serious illness, particularly in the south‐eastern region of the country. Moreover, the Rickettsia sp. strain Atlantic Rainforest cause milder clinical manifestations in south‐eastern, south and north‐east regions. This study has sought to analyse predictive factors for fatal SF. A case–control study was performed using disease notification records in Brazil. The cases included were individuals with laboratory confirmation and fatal progression of SF, while the controls included individuals with SF who were cured. A total of 386 cases and 415 controls were identified (1 : 1.1), and the cases and controls were similar in age. The factors identified as being protective against death were reported presence of ticks (odds ratio [OR], 0.60; 95% confidence interval [CI], 0.41–0.88), residing in urban areas (OR, 0.47, 95% CI, 0.31–0.74) and presenting lymphadenopathy (OR, 0.43; 95% CI, 0.23–0.82). Males exhibited a greater chance of death (OR, 1.57; 95% CI, 1.13–2.18), as did patients who were hospitalized (OR, 10.82; 95% CI, 6.38–18.35) and who presented hypotension or shock (OR, 10.80; 95% CI, 7.33–15.93), seizures (OR, 11.24; 95% CI, 6.49–19.45) and coma (OR of 15.16; 95% CI, 8.51–27.02). The study demonstrates the severity profile of the SF cases, defined either as the frequency of hospitalization (even in cases that were cured) or as the increased frequency of the clinical complications typically found in critical patients. Opportune clinical diagnosis, a careful evaluation of the epidemiological aspects of the disease and adequate care for patients are determining factors for reducing SF fatality rates.
Bike Desks in the Classroom: Energy Expenditure, Physical Health, Cognitive Performance, Brain Functioning, and Academic Performance
Authors: Torbeyns Tine , de Geus Bas , Bailey Stephen , Decroix Lieselot , Van Cutsem Jeroen , De Pauw Kevin , Meeusen Romain 
Published: February 2017

Background:Physical activity is positively associated with physical health, cognitive performance, brain functioning and academic performance. The aim of this study is to investigate the influence of bike desks in the classroom on adolescents’ energy expenditure, physical health, cognitive performance, brain functioning and academic performance.Methods:Forty-four adolescents were randomly assigned to control group (CG) or intervention group (IG). During 5 months, the IG used a bike desk for 4 class hours/week. Energy expenditure was measured during 6 consecutive days. Anthropometric parameters, aerobic fitness, academic performance, cognitive performance and brain functioning were assessed before (T0) and after (T1) the intervention.Results:Energy expenditure of the IG was significantly higher during the class hours in which they used the bike desks relative to normal class hours. The CG had a significantly higher BMI at T1 relative to T0 while this was not significantly different for the IG. Aerobic fitness was significantly better in the IG at T1 relative to T0. No significant effects on academic performance cognitive performance and brain functioning were observed.Conclusions:As the implementation of bike desks in the classroom did not interfere with adolescents’ academic performance, this can be seen as an effective means of reducing in-class sedentary time and improving adolescents’ physical health.
Relation of Adolescents’ Physical Activity to After-School Recreation Environment
Authors: Thornton Christina M. , Cain Kelli L. , Conway Terry L. , Kerr Jacqueline , Saelens Brian E. , Frank Lawrence D. , Glanz Karen , Sallis James F. 
Published: February 2017

Background:The after-school period provides an opportune context for adolescent physical activity. This study examined how characteristics of after-school recreation environments related to adolescent physical activity.Methods:Participants were 889 adolescents aged 12 to 17 (mean = 14.1, SD = 1.4) from 2 US regions. Adolescents reported on whether their school offered after-school supervised physical activity, access to play areas/fields, and presence of sports facilities. Outcomes were accelerometer-measured after-school physical activity, reported physical activity on school grounds during nonschool hours, attainment of 60 minutes of daily physical activity excluding school physical education, and BMI-for-age z-score. Mixed regression models adjusted for study design, region, sex, age, ethnicity, vehicles/licensed drivers in household, and distance to school.Results:School environment variables were all significantly associated with self-reported physical activity on school grounds during non-school hours (P < .001) and attainment of 60 minutes of daily physical activity (P < .05). Adolescents’ accelerometer-measured after-school physical activity was most strongly associated with access to supervised physical activity (P = .008).Conclusions:Policies and programs that provide supervised after-school physical activity and access to play areas, fields, and sports facilities may help adolescents achieve daily physical activity recommendations.
Antitrypanosomal Activity of Sterol 14α-Demethylase (CYP51) Inhibitors VNI and VFV in the Swiss Mouse Models of Chagas Disease Induced by the Trypanosoma cruzi Y Strain
Authors: Guedes-da-Silva F. H. , Batista D. G. J. , Da Silva C. F. , De Araújo J. S. , Pavão B. P. , Simões-Silva M. R. , Batista M. M. , Demarque K. C. , Moreira O. C. , Britto C. , Lepesheva G. I. , Soeiro M. N. C. 
Published: February 2017

ABSTRACT

Chagas disease is a life-threatening infection caused by a variety of genetically diverse strains of the protozoan parasite
Trypanosoma cruzi
. The current treatment (benznidazole and nifurtimox) is unsatisfactory, and potential alternatives include inhibitors of sterol 14α-demethylase (CYP51), the cytochrome P450 enzyme essential for the biosynthesis of sterols in eukaryotes and the major target of clinical and agricultural antifungals. Here we performed a comparative investigation of two protozoon-specific CYP51 inhibitors, VNI and its CYP51 structure-based derivative VFV, in the murine models of infection caused by the Y strain of
T. cruzi
. The effects of different treatment regimens and drug delivery vehicles were evaluated in animals of both genders, with benznidazole serving as the reference drug. Regardless of the treatment scheme or delivery vehicle, VFV was more potent in both genders, causing a >99.7% peak parasitemia reduction, while the VNI values varied from 91 to 100%. Treatments with VNI and VFV resulted in 100% animal survival and 0% natural relapse after the end of therapy, though, except for the 120-day treatment schemes with VFV, relapses after three cycles of immunosuppression were observed in each animal group, and quantitative PCR analysis revealed a very light parasite load in the blood samples (sometimes below or near the detection limit, which was 1.5 parasite equivalents/ml). Our studies support further investigations of this class of compounds, including their testing against other
T. cruzi
strains and in combination with other drugs.
Salmonella enterica Serovar Typhi Lipopolysaccharide O-Antigen Modification Impact on Serum Resistance and Antibody Recognition
Authors: Kintz Erica , Heiss Christian , Black Ian , Donohue Nicholas , Brown Naj , Davies Mark R. , Azadi Parastoo , Baker Stephen , Kaye Paul M. , van der Woude Marjan 
Published: February 2017

ABSTRACT

Salmonella enterica
serovar Typhi is a human-restricted Gram-negative bacterial pathogen responsible for causing an estimated 27 million cases of typhoid fever annually, leading to 217,000 deaths, and current vaccines do not offer full protection. The O-antigen side chain of the lipopolysaccharide is an immunodominant antigen, can define host-pathogen interactions, and is under consideration as a vaccine target for some Gram-negative species. The composition of the O-antigen can be modified by the activity of glycosyltransferase (
gtr
) operons acquired by horizontal gene transfer. Here we investigate the role of two
gtr
operons that we identified in the
S
. Typhi genome. Strains were engineered to express specific
gtr
operons. Full chemical analysis of the O-antigens of these strains identified
gtr
-dependent glucosylation and acetylation. The glucosylated form of the O-antigen mediated enhanced survival in human serum and decreased complement binding. A single nucleotide deviation from an epigenetic phase variation signature sequence rendered the expression of this glucosylating
gtr
operon uniform in the population. In contrast, the expression of the acetylating
gtrC
gene is controlled by epigenetic phase variation. Acetylation did not affect serum survival, but phase variation can be an immune evasion mechanism, and thus, this modification may contribute to persistence in a host. In murine immunization studies, both O-antigen modifications were generally immunodominant. Our results emphasize that natural O-antigen modifications should be taken into consideration when assessing responses to vaccines, especially O-antigen-based vaccines, and that the
Salmonella
gtr
repertoire may confound the protective efficacy of broad-ranging
Salmonella
lipopolysaccharide conjugate vaccines.
Gas Sensing and Signaling in the PAS-Heme Domain of the Pseudomonas aeruginosa Aer2 Receptor
Authors: Garcia Darysbel , Orillard Emilie , Johnson Mark S. , Watts Kylie J. 
Published: February 2017

ABSTRACT

The Aer2 chemoreceptor from
Pseudomonas aeruginosa
contains a PAS sensing domain that coordinates
b
-type heme and signals in response to the binding of O
2
, CO, or NO. PAS-heme structures suggest that Aer2 uniquely coordinates heme via a His residue on a 3
10
helix (H234 on Eη), stabilizes O
2
binding via a Trp residue (W283), and signals via both W283 and an adjacent Leu residue (L264). Ligand binding may displace L264 and reorient W283 for hydrogen bonding to the ligand. Here, we clarified the mechanisms by which Aer2-PAS binds heme, regulates ligand binding, and initiates conformational signaling. H234 coordinated heme, but additional hydrophobic residues in the heme cleft were also critical for stable heme binding. O
2
appeared to be the native Aer2 ligand (dissociation constant [

K
d

] of 16 μM). With one exception, mutants that bound O
2
could signal, whereas many mutants that bound CO could not. W283 stabilized O
2
binding but not CO binding, and it was required for signal initiation; W283 mutants that could not stabilize O
2
were rapidly oxidized to Fe(III). W283F was the only Trp mutant that bound O
2
with wild-type affinity. The size and nature of residue 264 was important for gas binding and signaling: L264W blocked O
2
binding, L264A and L264G caused O
2
-mediated oxidation, and L264K formed a hexacoordinate heme. Our data suggest that when O
2
binds to Aer2, L264 moves concomitantly with W283 to initiate the conformational signal. The signal then propagates from the PAS domain to regulate the C-terminal HAMP and kinase control domains, ultimately modulating a cellular response.

IMPORTANCE
Pseudomonas aeruginosa
is a ubiquitous environmental bacterium and opportunistic pathogen that infects multiple body sites, including the lungs of cystic fibrosis patients.
P. aeruginosa
senses and responds to its environment via four chemosensory systems. Three of these systems regulate biofilm formation, twitching motility, and chemotaxis. The role of the fourth system, Che2, is unclear but has been implicated in virulence. The Che2 system contains a chemoreceptor called Aer2, which contains a PAS sensing domain that binds heme and senses oxygen. Here, we show that Aer2 uses unprecedented mechanisms to bind O
2
and initiate signaling. These studies provide both the first functional corroboration of the Aer2-PAS signaling mechanism previously proposed from structure as well as a signaling model for Aer2-PAS receptors.
Regulation of Polyhydroxybutyrate Accumulation in Sinorhizobium meliloti by the
Trans
-Encoded Small RNA MmgR
Authors: Lagares Antonio , Borella Germán Ceizel , Linne Uwe , Becker Anke , Valverde Claudio 
Published: February 2017

ABSTRACT

Riboregulation has a major role in the fine-tuning of multiple bacterial processes. Among the RNA players,
trans
-encoded untranslated small RNAs (sRNAs) regulate complex metabolic networks by tuning expression from multiple target genes in response to numerous signals. In
Sinorhizobium meliloti
, over 400 sRNAs are expressed under different stimuli. The sRNA MmgR (standing for
M
akes
m
ore
g
ranules
R
egulator) has been of particular interest to us since its sequence and structure are highly conserved among the alphaproteobacteria and its expression is regulated by the amount and quality of the bacterium's available nitrogen source. In this work, we explored the biological role of MmgR in
S. meliloti
2011 by characterizing the effect of a deletion of the internal conserved core of
mmgR
(
mmgR
Δ33–51
). This mutation resulted in larger amounts of polyhydroxybutyrate (PHB) distributed into more intracellular granules than are found in the wild-type strain. This phenotype was expressed upon cessation of balanced growth owing to nitrogen depletion in the presence of surplus carbon (i.e., at a carbon/nitrogen molar ratio greater than 10). The normal PHB accumulation was complemented with a wild-type
mmgR
copy but not with unrelated sRNA genes. Furthermore, the expression of
mmgR
limited PHB accumulation in the wild type, regardless of the magnitude of the C surplus. Quantitative proteomic profiling and quantitative reverse transcription-PCR (qRT-PCR) revealed that the absence of MmgR results in a posttranscriptional overexpression of both PHB phasin proteins (PhaP1 and PhaP2). Together, our results indicate that the widely conserved alphaproteobacterial MmgR sRNA fine-tunes the regulation of PHB storage in
S. meliloti
.

IMPORTANCE
High-throughput RNA sequencing has recently uncovered an overwhelming number of
trans
-encoded small RNAs (sRNAs) in diverse prokaryotes. In the nitrogen-fixing alphaproteobacterial symbiont of alfalfa root nodules
Sinorhizobium meliloti
, only four out of hundreds of identified sRNA genes have been functionally characterized. Thus, uncovering the biological role of sRNAs currently represents a major issue and one that is particularly challenging because of the usually subtle quantitative regulation contributed by most characterized sRNAs. Here, we have characterized the function of the broadly conserved alphaproteobacterial sRNA gene
mmgR
in
S. meliloti
. Our results strongly suggest that
mmgR
encodes a negative regulator of the accumulation of polyhydroxybutyrate, the major carbon and reducing power storage polymer in
S. meliloti
cells growing under conditions of C/N overbalance.