A polytetrafluoroethylene porous membrane and dimethylhexadecylamine quaternized poly (vinyl benzyl chloride) composite membrane for intermediate temperature fuel cells

AbstractA composite material for phosphoric acid (PA) loaded membrane was prepared using a porous polytetrafluoroethylene (PTFE) thin film. N, N-Dimethylhexadecylamine partially quaternized poly (vinyl benzyl chloride) (qPVBzCl−) was synthesized as the substrate for the phosphoric acid loaded polymer membrane. SEM observation indicated that the pores were filled with the qPVBzCl−. The maximum PA loading level was calculated to be 4.67–5.12 per repeat unit on average. TGA results showed that resultant composite membrane was stable in the intermediate temperature from 100 °C to 200 °C. The composite membrane tensile stress was 56.23 MPa, and the Young's Modulus was 0.25 GPa, and the fractured elongation was 23%. The conductivity of the composite membrane after the PA addition (H3PO4@PTFE/qPVBzCl−) increased from 0.085 S cm−1 to 0.11 S cm−1 from 105 °C to 180 °C. The peak power density of the H2/O2 at 175 °C under low humidity condition (<1%) for H3PO4@PTFE/qPVBzCl− membranes was 360 mW cm−2

The De Jong Gierveld short scales for emotional and social loneliness: tested on data from 7 countries in the UN generations and gender surveys

Loneliness concerns the subjective evaluation of the situation individuals are involved in, characterized either by a number of relationships with friends and colleagues which is smaller than is considered desirable (social loneliness), as well as situations where the intimacy in confidant relationships one wishes for has not been realized (emotional loneliness). To identify people who are lonely direct questions are not sufficient; loneliness scales are preferred. In this article, the quality of the three-item scale for emotional loneliness and the three-item scale for social loneliness has been investigated for use in the following countries participating in the United Nations “Generations and Gender Surveys”: France, Germany, the Netherlands, Russia, Bulgaria, Georgia, and Japan. Sample sizes for the 7 countries varied between 8,158 and 12,828. Translations of the De Jong Gierveld loneliness scale have been tested using reliability and validity tests including a confirmatory factor analysis to test the two-dimensional structure of loneliness. Test outcomes indicated for each of the countries under investigation reliable and valid scales for emotional and social loneliness, respectively

Resource Competition Triggers the Co-Evolution of Long Tongues and Deep Corolla Tubes

Background: It is normally thought that deep corolla tubes evolve when a plant’s successful reproduction is contingent on having a corolla tube longer than the tongue of the flower’s pollinators, and that pollinators evolve ever-longer tongues because individuals with longer tongues can obtain more nectar from flowers. A recent model shows that, in the presence of pollinators with long and short tongues that experience resource competition, coexisting plant species can diverge in corolla-tube depth, because this increases the proportion of pollen grains that lands on co-specific flowers. Methodology/Principal Findings: We have extended the model to study whether resource competition can trigger the coevolution of tongue length and corolla-tube depth. Starting with two plant and two pollinator species, all of them having the same distribution of tongue length or corolla-tube depth, we show that variability in corolla-tube depth leads to divergence in tongue length, provided that increasing tongue length is not equally costly for both species. Once the two pollinator species differ in tongue length, divergence in corolla-tube depth between the two plant species ensues. Conclusions/Significance: Co-evolution between tongue length and corolla-tube depth is a robust outcome of the model, obtained for a wide range of parameter values, but it requires that tongue elongation is substantially easier for one pollinator species than for the other, that pollinators follow a near-optimal foraging strategy, that pollinators experienc

Widespread range expansions shape latitudinal variation in insect thermal limits

I thank the authors of previous studies on global variation in insect thermal tolerances who have generously provided open access use of their data sets.Peer reviewedPostprin

The Prevalence of Human Papillomavirus in Pediatric Tonsils: a Systematic Review of the Literature

BACKGROUND: HPV-related head and neck cancer rates have been increasing in recent years, with the tonsils being the most commonly affected site. However, the current rate of HPV infection in the pediatric population remains poorly defined. The objective of this study was to systematically review and evaluate the prevalence and distribution of HPV in the tonsils of pediatric patients undergoing routine tonsillectomy. METHODS AND RESULTS: The literature was searched using PubMed, EMBASE, Scopus, CINAHL, Cochrane Library, and ProQuest Dissertations & Theses Global databases (inception to December 2017) by two independent review authors. Inclusion criteria included articles which evaluated the prevalence of HPV in a pediatric cohort without known warts or recurrent respiratory papillomatosis, those which used tonsil biopsy specimens for analysis, and those with six or more subjects and clear outcomes reported. Eleven studies met the inclusion criteria. Using the Oxford Clinical Evidence-based Medicine (OCEBM) guidelines, two reviewers appraised the level of evidence of each study, extracted data, and resolved discrepancies by consensus. The systematic review identified 11 articles (n = 2520). Seven studies detected HPV in the subject population, with prevalence values ranging from 0 to 21%. The level of evidence for all included studies was OCEBM Level 3. CONCLUSIONS: HPV may be present in pediatric tonsillectomy specimens; however, the largest included study demonstrated a prevalence of 0%. Future testing should be performed using methods with high sensitivities and specificities, such as reverse transcript real-time PCR or digital droplet PCR

Comparative efficacy of ultrasound-guided and stimulating popliteal-sciatic perineural catheters for postoperative analgesia

Perineural catheter insertion using ultrasound guidance alone is a relatively new approach. Previous studies have shown that ultrasound-guided catheters take less time to place with high placement success rates, but the analgesic efficacy compared with the established stimulating catheter technique remains unknown. We tested the hypothesis that popliteal-sciatic perineural catheter insertion relying exclusively on ultrasound guidance results in superior postoperative analgesia compared with stimulating catheters. Preoperatively, subjects receiving a popliteal-sciatic perineural catheter for foot or ankle surgery were assigned randomly to either ultrasound guidance (bolus via needle with non-stimulating catheter insertion) or electrical stimulation (bolus via catheter). We used 1.5% mepivacaine 40 mL for the primary surgical nerve block and 0.2% ropivacaine (basal 8 mL·hr−1; bolus 4 mL; 30 min lockout) was infused postoperatively. The primary outcome was average surgical pain on postoperative day one. Forty of the 80 subjects enrolled were randomized to each treatment group. One of 40 subjects (2.5%) in the ultrasound group failed catheter placement per protocol vs nine of 40 (22.5%) in the stimulating catheter group (P = 0.014). The difference in procedural duration (mean [95% confidence interval (CI)]) was −6.48 (−9.90 - −3.05) min, with ultrasound requiring 7.0 (4.0-14.1) min vs stimulation requiring 11.0 (5.0-30.0) min (P &lt; 0.001). The average pain scores of subjects who provided data on postoperative day one were somewhat higher for the 33 ultrasound subjects than for the 26 stimulation subjects (5.0 [1.0-7.8] vs 3.0 [0.0-6.5], respectively; P = 0.032), a difference (mean [95%CI]) of 1.37 (0.03-2.71). For popliteal-sciatic perineural catheters, ultrasound guidance takes less time and results in fewer placement failures compared with stimulating catheters. However, analgesia may be mildly improved with successfully placed stimulating catheters. Clinical trial registration number NCT00876681

Learning to Use Illumination Gradients as an Unambiguous Cue to Three Dimensional Shape

The luminance and colour gradients across an image are the result of complex interactions between object shape, material and illumination. Using such variations to infer object shape or surface colour is therefore a difficult problem for the visual system. We know that changes to the shape of an object can affect its perceived colour, and that shading gradients confer a sense of shape. Here we investigate if the visual system is able to effectively utilise these gradients as a cue to shape perception, even when additional cues are not available. We tested shape perception of a folded card object that contained illumination gradients in the form of shading and more subtle effects such as inter-reflections. Our results suggest that observers are able to use the gradients to make consistent shape judgements. In order to do this, observers must be given the opportunity to learn suitable assumptions about the lighting and scene. Using a variety of different training conditions, we demonstrate that learning can occur quickly and requires only coarse information. We also establish that learning does not deliver a trivial mapping between gradient and shape; rather learning leads to the acquisition of assumptions about lighting and scene parameters that subsequently allow for gradients to be used as a shape cue. The perceived shape is shown to be consistent for convex and concave versions of the object that exhibit very different shading, and also similar to that delivered by outline, a largely unrelated cue to shape. Overall our results indicate that, although gradients are less reliable than some other cues, the relationship between gradients and shape can be quickly assessed and the gradients therefore used effectively as a visual shape cue

A Prospective study of the association between weight changes and self-rated health

<p>Abstract</p> <p>Background</p> <p>Obesity and self-rated health (SRH) are strong predictors of morbidity and mortality but their interrelation is sparsely studied. The aim of this study was to analyse the association between weight changes and changes in SRH among women. We also examined if poor SRH at baseline was associated with later weight gain.</p> <p>Methods</p> <p>The Danish Nurse Cohort Study is a prospective population study (1993–1999) and comprises 13,684 female nurses aged 44 to 69 years. Logistic regression analyses were used to examine the association between weight changes and changes in SRH.</p> <p>Results</p> <p>Women who gained weight during the study period had higher odds of reporting poorer self-rated health (Odds Ratio (OR): 1.18, 95% CI: 1.04–1.35). Weight loss among overweight women, did not result in an increase in self-rated health ratings, in fully adjusted analyses (0.96 (95% CI: 0.76–1.23). Poor self-rated health combined with normal weight at first examination was associated with higher odds of later weight gain (OR: 1.29, 95% CI: 1.10–1.51).</p> <p>Conclusion</p> <p>Weight changes may result in lower SRH. Further, poor self-rated health at baseline seems to predict an increase in weight, among women without any longstanding chronic diseases. Future obesity prevention may focus on normal weight individuals with poor SRH.</p