455 research outputs found
Chlamydia trachomatis Pgp3 antibody persists and correlates with self-reported infection and behavioural risks in a blinded cohort study
Chlamydia trachomatis (Ct) serological studies in populations could help monitor changes in lifetime cumulative risk of infection. We developed a double-antigen sandwich ELISA based on the Ct-specific Pgp3 antigen, then tested blind stored sera from over 800 participants in a New Zealand birth cohort from Dunedin at ages 26, 32 and 38. The double-antigen sandwich ELISA was more sensitive than our previously characterised indirect Pgp3 ELISA. Pgp3 antibody was detected more often in women compared to men and correlated with increasing numbers of sexual partners, self-reported Ct, and younger age at sexual debut in both women and men. At age 26, 24.1% (99/411) of women were Pgp3 seropositive, as were 79.5% (35/44) of those reporting Ct infection; Pgp3 antibody persisted to age 38 in 96.5% (83/86). In men at age 26, the figures were 10.7% (47/442) and 25.0% (6/24), respectively, with high (83.9%) antibody persistence to age 38. At age 38, among those Pgp3 seropositive, 63.3% of women and 83.1% of men had not reported Ct infection. Thus, Ct-specific Pgp3 antibody was detected in most women reporting Ct infection and correlated with risk of infection in those who did not, with most infections remaining undetected. As this antibody persisted for at least twelve years in 96% of these women, serology could be used to evaluate Ct prevention programmes among women
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Experimental investigations of Per- and Poly-fluoroalkyl substances (PFAS) degradation by non-thermal plasma in aqueous solutions
Data Availability:
Data will be made available on request.Supplementary material is available online at: https://www.sciencedirect.com/science/article/pii/S2213343723023278?via%3Dihub#sec0100 .The treatability of perfluorocarboxylic acids (PFCA) (perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA)) and perfluorosulfonic acids (PFSA) (PFBS, Perfluorooctanesulfonic acid PFHxS and Perfluorooctanesulfonic acid (PFOS)) via a bubble column with non-thermal plasma discharges in the argon headspace were investigated in individual solutions and from surface water sourced from a contaminated site. High degradation (>90%) could be achieved for PFOA, PFHxS and PFOS within 40 min treating the contaminated surface water. Overall, treatability correlated with the length of the perfluorinated carbon chain, with a decrease in treatability associated with a reduction of the length of the perfluorinated backbone. Experiments with prepared PFAS solutions at initial concentrations of 10, 25 and 50 μg/L found higher initial concentrations of PFCA and PFSA were associated with faster degradation rates suggesting the treatment efficiency was limited by mass transfer of PFAS. Negligible breakdown was observed for PFBA at any of the concentrations trialled, indicating limitations when treating more hydrophilic PFAS, which may require combining this treatment approach with a polishing step, such as nanofiltration.This work was funded by the Australian Research Council’s Special Research Initiative on PFAS (SR180200046). Additionally, we acknowledge the support by the Australian Government Research Training Program (RTP) scholarship and David Cook (Ventia, formerly ICD Asia Pacific) for providing the contaminated surface water samples, Dr. Trevor Walker (Ventia, formerly ICD Asia Pacific) for his technical support and Charles Grimison (Ventia) for his time and technical input reviewing this manuscript. This research was facilitated by access to Sydney Mass Spectrometry, a core research facility at the University of Sydney
Caterpillars and fungal pathogens: two co-occurring parasites of an ant-plant mutualism
In mutualisms, each interacting species obtains resources from its partner that it would obtain less efficiently if alone, and so derives a net fitness benefit. In exchange for shelter (domatia) and food, mutualistic plant-ants protect their host myrmecophytes from herbivores, encroaching vines and fungal pathogens. Although selective filters enable myrmecophytes to host those ant species most favorable to their fitness, some insects can by-pass these filters, exploiting the rewards supplied whilst providing nothing in return. This is the case in French Guiana for Cecropia obtusa (Cecropiaceae) as Pseudocabima guianalis caterpillars (Lepidoptera, Pyralidae) can colonize saplings before the installation of their mutualistic Azteca ants. The caterpillars shelter in the domatia and feed on food bodies (FBs) whose production increases as a result. They delay colonization by ants by weaving a silk shield above the youngest trichilium, where the FBs are produced, blocking access to them. This probable temporal priority effect also allows female moths to lay new eggs on trees that already shelter caterpillars, and so to occupy the niche longer and exploit Cecropia resources before colonization by ants. However, once incipient ant colonies are able to develop, they prevent further colonization by the caterpillars. Although no higher herbivory rates were noted, these caterpillars are ineffective in protecting their host trees from a pathogenic fungus, Fusarium moniliforme (Deuteromycetes), that develops on the trichilium in the absence of mutualistic ants. Therefore, the Cecropia treelets can be parasitized by two often overlooked species: the caterpillars that shelter in the domatia and feed on FBs, delaying colonization by mutualistic ants, and the fungal pathogen that develops on old trichilia. The cost of greater FB production plus the presence of the pathogenic fungus likely affect tree growth
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Influence of bubble size on perfluorooctanesulfonic acid degradation in a pilot scale non-thermal plasma treatment reactor
Data availability:
Data will be made available on request.Supplementary data are available online at: https://www.sciencedirect.com/science/article/pii/S1385894724028365#s0125 .A 25L working volume non-thermal plasma-based treatment reactor was trialled to destroy per- and polyfluoroalkyl substances (PFAS) utilising argon bubbles to transport PFAS to the surface to be destroyed with plasma interaction at the argon-liquid interface. The breakdown rate of PFAS and the system's overall energy efficiency could be improved while minimising gas usage by utilising small bubbles (0.6–0.7 mm d32) to maximise the transport of PFAS to the plasma discharge for destruction. Vertically scaling the treatment reactor dimensions increases the overall liquid height and dwell time for bubbles to contact and transport PFAS molecules to the surface. The removal rate of perfluorooctane sulfonate (PFOS) correlated with the total surface area of the gas. Significant concentration gradients of PFOS could be observed when sampling from different liquid heights within the 25 L reactor. A one-dimensional model of mass transfer to the surface of rising bubbles was developed and gave good predictions of the overall rates of PFOS breakdown with modelled time constants of 0.14–0.18 min−1 versus 0.16 ± 0.01 min−1 for the fine bubble diffuser, and 0.048–0.053 min−1 versus 0.06 min−1 for the medium bubble diffuser. The time constant compared favourably with similar experiments at the 2 L scale of 0.11 min−1.This work was funded by the Australian Research Council’s Special Research Initiative on PFAS (SR180200046). Additionally, we acknowledge the support by the Australian Government Research Training Program (RTP) scholarship and David Cook (Ventia, formerly ICD Asia Pacific) for providing the contaminated surface water samples, Dr. Trevor Walker (Ventia, formerly ICD Asia Pacific) for his technical support and Charles Grimison (Ventia) for his time and technical input reviewing this manuscript. This research was facilitated by access to Sydney Mass Spectrometry, a core research facility at the University of Sydney. A/Prof John Kavanagh’s visit to DTU was funded by the University of Sydney and Vojtěch Kunc assisted with some bubble size and OTR measurements
Policy Adjustment in a Dynamic Economic Game
Making sequential decisions to harvest rewards is a notoriously difficult problem. One difficulty is that the real world is not stationary and the reward expected from a contemplated action may depend in complex ways on the history of an animal's choices. Previous functional neuroimaging work combined with principled models has detected brain responses that correlate with computations thought to guide simple learning and action choice. Those works generally employed instrumental conditioning tasks with fixed action-reward contingencies. For real-world learning problems, the history of reward-harvesting choices can change the likelihood of rewards collected by the same choices in the near-term future. We used functional MRI to probe brain and behavioral responses in a continuous decision-making task where reward contingency is a function of both a subject's immediate choice and his choice history. In these more complex tasks, we demonstrated that a simple actor-critic model can account for both the subjects' behavioral and brain responses, and identified a reward prediction error signal in ventral striatal structures active during these non-stationary decision tasks. However, a sudden introduction of new reward structures engages more complex control circuitry in the prefrontal cortex (inferior frontal gyrus and anterior insula) and is not captured by a simple actor-critic model. Taken together, these results extend our knowledge of reward-learning signals into more complex, history-dependent choice tasks. They also highlight the important interplay between striatum and prefrontal cortex as decision-makers respond to the strategic demands imposed by non-stationary reward environments more reminiscent of real-world tasks
Expression and trans-specific polymorphism of self-incompatibility RNases in Coffea (Rubiaceae)
Self-incompatibility (SI) is widespread in the angiosperms, but identifying the biochemical components of SI mechanisms has proven to be difficult in most lineages. Coffea (coffee; Rubiaceae) is a genus of old-world tropical understory trees in which the vast majority of diploid species utilize a mechanism of gametophytic self-incompatibility (GSI). The S-RNase GSI system was one of the first SI mechanisms to be biochemically characterized, and likely represents the ancestral Eudicot condition as evidenced by its functional characterization in both asterid (Solanaceae, Plantaginaceae) and rosid (Rosaceae) lineages. The S-RNase GSI mechanism employs the activity of class III RNase T2 proteins to terminate the growth of "self" pollen tubes. Here, we investigate the mechanism of Coffea GSI and specifically examine the potential for homology to S-RNase GSI by sequencing class III RNase T2 genes in populations of 14 African and Madagascan Coffea species and the closely related self-compatible species Psilanthus ebracteolatus. Phylogenetic analyses of these sequences aligned to a diverse sample of plant RNase T2 genes show that the Coffea genome contains at least three class III RNase T2 genes. Patterns of tissue-specific gene expression identify one of these RNase T2 genes as the putative Coffea S-RNase gene. We show that populations of SI Coffea are remarkably polymorphic for putative S-RNase alleles, and exhibit a persistent pattern of trans-specific polymorphism characteristic of all S-RNase genes previously isolated from GSI Eudicot lineages. We thus conclude that Coffea GSI is most likely homologous to the classic Eudicot S-RNase system, which was retained since the divergence of the Rubiaceae lineage from an ancient SI Eudicot ancestor, nearly 90 million years ago.United States National Science Foundation [0849186]; Society of Systematic Biologists; American Society of Plant Taxonomists; Duke University Graduate Schoolinfo:eu-repo/semantics/publishedVersio
The TOPSHOCK study: Effectiveness of radial shockwave therapy compared to focused shockwave therapy for treating patellar tendinopath - design of a randomised controlled trial
Background: Patellar tendinopathy is a chronic overuse injury of the patellar tendon that is especially prevalent in people who are involved in jumping activities. Extracorporeal Shockwave Therapy is a relatively new treatment modality for tendinopathies. It seems to be a safe and promising part of the rehabilitation program for patellar tendinopathy. Extracorporeal Shockwave Therapy originally used focused shockwaves. Several years ago a new kind of shockwave therapy was introduced: radial shockwave therapy. Studies that investigate the effectiveness of radial shockwave therapy as treatment for patellar tendinopathy are scarce. Therefore the aim of this study is to compare the effectiveness of focussed shockwave therapy and radial shockwave therapy as treatments for patellar tendinopathy. Methods/design: The TOPSHOCK study (Tendinopathy Of Patella SHOCKwave) is a two-armed randomised controlled trial in which the effectiveness of focussed shockwave therapy and radial shockwave therapy are directly compared. Outcome assessors and patients are blinded as to which treatment is given. Patients undergo three sessions of either focused shockwave therapy or radial shockwave therapy at 1-week intervals, both in combination with eccentric decline squat training. Follow-up measurements are scheduled just before treatments 2 and 3, and 1, 4, 7 and 12 weeks after the final treatment. The main outcome measure is the Dutch VISA-P questionnaire, which asks for pain, function and sports participation in subjects with patellar tendinopathy. Secondary outcome measures are pain determined with a VAS during ADL, sports and decline squats, rating of subjective improvement and overall satisfaction with the treatment. Patients will also record their sports activities, pain during and after these activities, and concurrent medical treatment on a weekly basis in a web-based diary. Results will be analysed according to the intention-to-treat principle. Discussion: The TOPSHOCK study is the first randomised controlled trial that directly compares the effectiveness of focused shockwave therapy and radial shockwave therapy, both in combination with eccentric decline squat training, for treating patellar tendinopathy. Trial registration: Trial registration number NTR2774
The vitamin D receptor polymorphism in the translation initiation codon is a risk factor for insulin resistance in glucose tolerant Caucasians
BACKGROUND: Although vitamin D receptor (VDR) polymorphisms have been shown to be associated with abnormal glucose metabolism, the reported polymorphisms are unlikely to have any biological consequences. The VDR gene has two potential translation initiation sites. A T-to-C polymorphism has been noted in the first ATG (f allele), abolishing the first translation initiation site and resulting in a peptide lacking the first three amino acids (F allele). We examined the role of this polymorphism in insulin sensitivity and beta cell function. This study included 49 healthy Caucasian subjects (28 females, age 28 ± 1 years old, body mass index 24.57 ± 0.57 kg/m(2), waist-hip ratio 0.81 ± 0.01 cm/cm). They were all normotensive (less than 140/90 mmHg) and glucose tolerant, which was determined by a standard 75-gm oral glucose tolerance test. Their beta cell function (%B) and insulin sensitivity (%S) were calculated based on the Homeostasis Model Assessment (HOMA). Their genotypes were determined by a polymerase chain reaction-restriction fragment length polymorphism analysis. Phenotypes were compared between genotypic groups. RESULTS: There were 18 FF, 21 Ff, and 10 ff subjects. Since only 10 ff subjects were identified, they were pooled with the Ff subjects during analyses. The FF and Ff/ff groups had similar glucose levels at each time point before and after a glucose challenge. The Ff/ff group had higher insulin levels than the FF group at fasting (P=0.006), 30 minutes (P=0.009), 60 minutes (P=0.049), and 90 minutes (P=0.042). Furthermore, the Ff/ff group also had a larger insulin area under the curve than the FF group (P=0.009). While no difference was noted in %B, the Ff/ff group had a lower %S than the FF group (0.53 vs. 0.78, P=0.006). A stepwise regression analysis confirmed that the Fok I polymorphism was an independent determinant for %S, accounting for 29.3% of variation in %S when combined with waist-hip ratio. CONCLUSIONS: We report that the Fok I polymorphism at the VDR gene locus is associated with insulin sensitivity, but has no influence on beta cell function in healthy Caucasians. Although this polymorphism has been shown to affect the activation of vitamin D-dependent transcription, the molecular basis of the association between this polymorphism and insulin resistance remains to be determined
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