Are metal-free pristine carbon nanotubes electrocatalytically active?

Metal-free (i.e., residual metallic impurities-blocked) carbon nanotubes (CNTs) do show electrocatalytic activity for H2 evolution, O2 evolution and O2 reduction reactions (HER, OER & ORR) in alkaline solutions, but their activities strongly depend on the number of walls or inner tubes with a maximum for CNTs with 2–3 walls

Leukoencephalopathy resolution after atypical mycobacterial treatment: a case report

Abstract\ud \ud Background\ud Association of leukoencephalopathy and atypical mycobacteriosis has been rarely reported. We present a case that is relevant for its unusual presentation and because it may shed further light on the pathogenic mechanisms underlying reversible encephalopathies.\ud \ud \ud Case report\ud We report the case of a Hispanic 64-year-old woman with cognitive decline and extensive leukoencephalopathy. Magnetic resonance imaging revealed white-matter lesions with increased water diffusivity, without blood–brain-barrier disruption. Brain biopsy showed tissue rarefaction with vacuolation, mild inflammation, few reactive astrocytes and decreased aquaporin water-channel expression in the lesions. Six months later, she was diagnosed with atypical mycobacterial pulmonary infection. Brain lesions resolved after antimycobacterial treatment.\ud \ud \ud Conclusion\ud We hypothesize leukoencephalopathic changes and vasogenic edema were associated with decreased aquaporin expression. Further studies should clarify if reversible leukoencephalopathy has a causal relationship with decreased aquaporin expression and atypical mycobacterial infection, and mechanisms underlying leukoencephalopathy resolution after antimycobacterial treatment. This article may contribute to the understanding of pathogenic mechanisms underlying magnetic resonance imaging subcortical lesions and edema, which remain incompletely understood.Ministry of Education, Culture, Sports, Science and Technology (MEXT) of JapanHealth and Labor Sciences Research Grant on Intractable Diseases\ud (Neuroimmunological Diseases) from the Ministry of Health, Labor and\ud Welfare of Japa

Oxygen reduction electrocatalysis

This dissertation is focused on the investigation of the oxygen reduction reaction (ORR) utilizing both existing and newly discovered electrocatalysts. Interest in the ORR is motivated by its application in the cathodes of most fuel cells. The slow kinetics of the ORR are a major barrier to the widespread usage of fuel cells, thus motivating research aimed at increasing understanding of existing electrocatalysts and driving demand for the development of improved electrocatalysts for the ORR. The first section focuses on laccase, a multicopper oxidase that catalyzes the four-electron reduction of oxygen to water. Upon adsorption to an electrode surface, laccase is known to reduce oxygen at overpotentials lower than the best noble metal electrocatalysts usually employed. Whereas the electrocatalytic activity of laccase is well established on carbon electrodes, laccase does not typically adsorb to better defined noble metal surfaces in an orientation that allows for efficient electrocatalysis. In this work, anthracene-2-methanethiol (AMT) was employed to modify the surface of Au electrodes and the electrocatalytic activity of adsorbed laccase was examined. AMT facilitated the adsorption of laccase, and the onset of electrocatalytic oxygen reduction was observed as high as 1.13 VRHE. Linear Tafel behavior was observed with a 144 mV/dec slope, consistent with an outer-sphere single-electron transfer from the electrode to a Cu site in the enzyme as the rate-determining step of the oxygen reduction mechanism. Inspired by the multicopper active site of laccase, the second section focuses on the precipitation of an insoluble complex of copper(II) with 3,5-diamino-1,2,4-triazole onto a carbon black support that leads to the formation of an efficient catalyst for the ORR referred to as CuDAT. The oxygen-reduction activity is reported over a wide pH range from 1 to 13 and the onset of the ORR occurs at potentials as high as 0.86???VRHE, making CuDAT the most active synthetic copper-based electrocatalyst for the ORR reported to date. For the first time, ex situ magnetic susceptibility measurements were used to demonstrate the presence of multicopper sites on the electrode. The final section addresses the question of whether or not the active sites for the ORR in electrocatalysts based on carbon-supported transition-metal complexes are metal-centered as this has become controversial, especially for heat-treated materials. Some have proposed that the transition metal only serves to form highly active sites based on nitrogen and carbon. Here, we examine the oxygen reduction activity of carbon-supported iron(II) phthalocyanine (FePc) before and after pyrolysis at 800 ??C and CuDAT in the presence of several anions and small-molecule poisons, including fluoride, azide, thiocyanate, ethanethiol, and cyanide. CuDAT is poisoned in a manner consistent with a copper-based active site. Although FePc and pyrolyzed FePc are remarkably resilient to most poisons they are poisoned by cyanide indicative of iron-based active sites

Mpact of early nutrition on the development of lung immunity in the piglet

Abstract This thesis covers a variety of topics and analyses related to early nutrition on the impact it has on the development of lung immunity in the piglet. In the first section, an introduction is given. In short, neonates are susceptible to infection early in life, especially respiratory infections (Murphy et al. 2008). Respiratory infections are a major cause of morbidity and mortality in infants and children world-wide. The immune system exists to protect the host against infection and to help the neonate respond appropriately to critical transition periods of life, namely birth and weaning where the infant is exposed to a variety of new environmental and food antigens. Deficiencies of the immune system, both innate and adaptive immunity contribute to impaired host defense (Marodi and Notarangelo 2007) which can lead to increased susceptibility to infection. Exposure to dietary antigens influences the rate of maturation of the immune system (Kelly and Coutts 2000) and can even help provide a protective effect against infection. Breast milk is the optimal form of nutrition and is thought to help the immune system develop by providing signals to the immune system (Kelly and Coutts 2000), contributing bioactive components and stimulating the release of cytokines in peripheral blood mononuclear cells (PBMC) (Bessler et al. 1996) thus decreasing the risk of pneumonia (Chantry et al. 2006), upper respiratory, lower respiratory and gastrointestinal infections (Duijts et al. 2010). Despite the benefits of breast milk, only about 13% of infants are exclusively breastfed by 6 months of age (CDC 2010), therefore, increased understanding of lung immune characteristics and how they differ between breastfed and formula infants is necessitated. The next section of the thesis looks at developmental differences in lung, mediastinal lymph nodes, and thoracic lymph nodes in breastfed compared to formula-fed piglets. In this study, colostrum-fed newborn piglets were either fed medicated sow milk replacer formula beginning at 48 hours of life (n=11) or remained with the sow (n=12) throughout the duration of the study. On d7 and d21 postpartum, approximately half of the piglets in each group were euthanized and blood and tissue samples were collected. Immune cells in the lungs, MSLN and TLN were analyzed through a variety of techniques. T lymphocyte subpopulations were identified using flow cytometry, cytokine mRNA expression was evaluated via RT-PCR, and total IgG, IgM, and IgA concentrations in serum were analyzed using enzyme linked immunoabsorbant assay (ELISA). Both dietary (SR vs. FF) and developmental effects on immunological development were observed. Through flow cytometry, it was found that NK cells were affected by diet in TLN, but not in PBMC or MSLN. However, an effect of day (e.g. development) was seen in PBMC NK cells. CD4+CD8+ T cell ratios were not different between FF and SR piglets in PBMC; however, diet affected MSLN at d21 and TLN at d7. Expression of CD4+CD8+ double positive T cells in PBMC were affected by day, while diet effects were seen in TLN on d7 and MSLN on d21. mRNA expression was investigated in whole tissue samples from the lung, TLN, and MSLN. Diet also affected the mRNA expression of IL-1?? and TNF-?? in TLN, dectin, IFN-??, and TGF-??2, in MSLN and IFN-?? in lung tissue in which FF animals had higher mRNA expression than the SR counterpart. In addition, the expression of TLN IL-12 and dectin and MSLN IFN-?? decreased over time while lung IL-6, TGF-??1, INF-??, and TNF-?? increased over time. Turning to systemic immunity, serum IgG concentrations were lower in the SR piglets than FF piglets (p<0.05), and IgG levels in d7 animals were higher than at d14 and d21 (p<0.05). Serum IgM concentrations were not significantly different in SR piglets compared to FF piglets nor did the concentrations exhibit developmental changes. Serum IgA levels were lower in the SR piglets when compared to the FF piglets (p<0.05), and IgA levels in d7 animals were higher than on d14 and d21 (P<0.05). The findings of this study have established a set of baseline measurements that establish the developmental changes in immune cells populations and cytokine expression in bronchial associated lymph tissues. Furthermore, these data demonstrated that differences exist between SR and FF piglets and provide a framework for future respiratory challenge studies to continue to pinpoint diet/immunological factors that increase the neonate???s ability to resist respiratory infections and recover more quickly from pathogenic invasion. This developmental study also established a foundation of normative changes over time for future studies to probe effectiveness of various formula components on mucosal lung immune development. The next section of the thesis discusses one component, ??-glucan, and the effect it has on mucosal lung immune development. In this study, piglets (n=5-6/group) were fed formula containing 0 (control), 5 (WGP5), 50 (WGP50), or 250 (WGP250) mg/L formula. Half of the piglets in each treatment were vaccinated (FV) by i.m. injection against influenza (Fluzone???, Sanofi Pasteur, Swiftwater, PA) on d7 and received a booster on d14. Piglets were euthanized on d7 and d21. Weight gain and formula intake were unaffected by diet or vaccination. Fluzone-specific serum IgG concentrations was measured by ELISA. FV piglets had higher (p<0.0001) fluzone-specific IgG titer at d14 and 21 than non-V piglets independent of diet. Vaccination response were unaffected by oral WGP supplementation. TNF-??, dectin, IL-1??, -2, -4, and -12 mRNA expression in lung were unaffected by age or dietary WGP. Lung TGF??-1 mRNA expression was greater (p<0.05) at d21 than d7, and lung TGF??-2 mRNA was lower (p<0.01) in all WGP diets compared to control. TNF-??, dectin, TGF??-1, IL-2, -4, -6, or -12 mRNA in mediastinal lymph nodes (MSLN) were unaffected by age or dietary WGP. In MSLN, TGF??-2 mRNA expression increased from d7 to d21 (p<0.05). TNF-??, TGF??-1, TGF??-2, IL-4, -6, or -12 mRNA in thorasic lymph nodes (TLN) were unaffected by age or dietary WGP. Dectin mRNA expression in TLN was lower at d21 compared to d7 (p<0.05). T-cell phenotypes were examined in MSLN and TLN by flow cytometry. In MSLN and TLN, CD4+ T-cells decreased, while CD8+ T-cells increased between d7 and d21 piglets (p<0.001), but these developmental patterns were unaffected by dietary WGP. Total serum IgG, IgM and IgA concentrations were also analyzed via ELISA. Total serum IgG, IgM and IgA were unaffected by WGP but followed typical developmental patterns. Thus, with the exception of reducing TGF??-2 mRNA in lung, dietary WGP did not affect cytokine expression, T-cell phenotypes or vaccination response in piglets. The thesis comes to a close with a discussion of overall conclusions and future directions for this work

Effect of pH and Azide on the Oxygen Reduction Reaction with a Pyrolyzed Fe Phthalocyanine Catalyst

The active site of pyrolyzed Fe/N/C electrocatalysts for the oxygen reduction reaction (ORR) has been a source of debate since the initial discovery that these materials demonstrated activity toward the ORR. Here we utilize carbon-supported iron­(II) phthalocyanine (FePc) that has been pyrolyzed at 800 °C in the absence and presence of azide in acidic, neutral, and basic environments in order to probe the ORR activity and mechanism of pyrolyzed Fe/N/C materials. The presence of azide served to enhance the ORR activity of this material in neutral electrolyte while having no effect in acid or base. Tafel slope differences in addition to the azide enhancement suggest an iron-centered active site for the ORR in pyrolyzed FePc and potentially other Fe/N/C electrocatalysts

Investigating the effectiveness of idiom intervention for 9–16‐year‐olds with developmental language disorder

BACKGROUND: Idiom skills are essential for children to access age-appropriate media, curriculum resources and teaching. Children with developmental language disorder (DLD) require support to develop the ability to understand and define idioms. However, research investigating one-to-one and classroom-based idiom skill intervention for children with DLD is limited. AIMS: To investigate the effectiveness of one-to-one speech and language therapist (SLT) and classroom-based interventions to develop and maintain progress of the idiom skills of 9-16-year-olds with DLD. METHODS & PROCEDURES: Forty-nine 9-16-year-olds from a specialist school for children with DLD received 20 intervention sessions to develop idiom skills during two school terms. Following a baseline period, 24 participants (aged 11-16) received ten 30-min one-to-one SLT intervention sessions once per week for the first term and classroom-based intervention for the second term. A total of 25 participants (aged 9-16) received the same intervention in the reverse order. Classroom-based intervention was delivered collaboratively by English teachers and SLTs during English lessons. All participants were assessed on their ability to identify, interpret, explain and use idioms 3 months before, directly before and after each intervention and 3 months post-intervention, using a bespoke assessment including 48 idioms randomly assigned to three sets: one-to-one intervention, classroom-based intervention and control idioms. OUTCOMES & RESULTS: Participants made significantly more progress during the intervention blocks than during the baseline period (block 1: d = 1.91; block 2: d = 1.01) and post-intervention levels were maintained 3 months post-intervention. Idiom skills showed significant progress when targeted through both one-to-one (d = 2.18) and classroom-based intervention (d = 0.91) but one-to-one intervention was significantly more effective than classroom-based intervention (d = 0.63). Examination of the specific idiom skills targeted revealed that although idiom identification and interpretation skills did not progress significantly more during intervention blocks than the baseline period, idiom explanation (block 1: d = 1.02; block 2: d = 0.97); and use did (block 1: d = 0.94; block 2: d = 0.81). One-to-one intervention was more effective than classroom-based intervention for developing idiom explanation (d = 1.32) and use (d = 0.65). Progress on control items was not significantly different during intervention blocks than during the baseline period overall or for any of the individual idiom skills. CONCLUSIONS & IMPLICATIONS: Both one-to-one SLT and classroom-based intervention are effective (although one-to-one is more effective) for teaching and maintaining idiom skills, particularly explanation and use. This means that SLTs and English teachers can help children to develop idiom skills which may enable better access to the curriculum and popular media

Dietary (1,3/1,6)-β-d-glucan decreases transforming growth factor β expression in the lung of the neonatal piglet

Identification and characterization of compounds that enhance the growth, development, and health of infants who are not breastfed continues to be a goal for nutritional science. This study explored the effects of one dietary component, (1,3/1,6)-. β-. d-glucan (Wellmune WGP), on lung immune development in the neonatal piglet. The hypothesis was that supplementation with WGP, a pathogen-associated molecular pattern, would enhance pathogen-responsive elements of the immune system, for instance, by increasing the size of the cytotoxic T-cell population or the expression of inflammatory cytokines. Piglets were fed a control formula or formula plus WGP at 1.8, 18, or 90 mg/kg body weight per day. Serum, thoracic lymph nodes (TLNs), mediastinal lymph nodes, and lung were collected at days 7 or 21. Immune parameters including tissue messenger RNA (mRNA) expression and T-cell phenotypes were analyzed. Normal developmental changes were observed, with a decrease in T-helper cells and an increase in cytotoxic T cells in both TLN and mediastinal lymph node, but there was no effect of WGP. Dietary WGP reduced the mRNA expression of transforming growth factor (TGF) β2 and tended to reduce the mRNA expression of TGF-. β1 in lung tissue. With the exception of reducing TGF-. β mRNA in the lung and tending to decrease the ratio of T helper to cytotoxic T cell in the TLN, dietary WGP did not affect lung-associated adaptive immunity in piglets. © 2013 Elsevier Inc