Resolving diverse oxygen transport pathways across Sr-doped lanthanum ferrite and metal-perovskite heterostructures

Perovskite structured transition metal oxides are important technological materials for catalysis and solid oxide fuel cell applications. Their functionality often depends on oxygen diffusivity and mobility through complex oxide heterostructures, which can be significantly impacted by structural and chemical modifications, such as doping. Further, when utilized within electrochemical cells, interfacial reactions with other components (e.g. Ni- and Cr-based alloy electrodes and interconnects) can influence the perovskite's reactivity and ion transport, leading to complex dependencies that are difficult to control in real-world environments. Here we use isotopic tracers and atom probe tomography to directly visualize oxygen diffusion and transport pathways across perovskite and metal-perovskite heterostructures, i.e. (Ni-Cr coated) Sr-doped lanthanum ferrite (LSFO). Annealing in 18O2(g) results in elemental and isotopic redistributions through oxygen exchange (OE) in the LSFO while Ni-Cr undergoes oxidation via multiple mechanisms and transport pathways. Complementary density functional theory (DFT) calculations at experimental conditions provide rationale for OE reaction mechanisms and reveal a complex interplay of different thermodynamic and kinetic drivers. Our results shed light on the fundamental coupling of defects and oxygen transport in an important class of catalytic materials.Comment: 39 pages, 10 figure

Ascorbic acid supplementation attenuates exercise-induced bronchoconstriction in patients with asthma

SummaryBackgroundPrevious research has shown that diet can modify the bronchoconstrictor response to exercise in asthmatic subjects.ObjectiveDetermine the effect of ascorbic acid supplementation on pulmonary function and several urinary markers of airway inflammation in asthmatic subjects with exercise-induced bronchoconstriction (EIB).MethodsEight asthmatic subjects with documented EIB participated in a randomized, placebo controlled double-blind crossover trial. Subjects entered the study on their usual diet and were placed on either 2 weeks of ascorbic acid supplementation (1500mg/day) or placebo, followed by a 1-week washout period, before crossing over to the alternative diet. Pre- and post-exercise pulmonary function, asthma symptom scores, fraction of exhaled nitric oxide (FENO), and urinary leukotriene (LT) C4–E4 and 9α, 11β-prostagladin (PG)F2] were assessed at the beginning of the trial (usual diet) and at the end of each treatment period.Results: The ascorbic acid diet significantly reduced (p<0.05) the maximum fall in post-exercise FEV1 (−6.4±2.4%) compared to usual (−14.3±1.6%) and placebo diet (−12.9±2.4%). Asthma symptoms scores significantly improved (p<0.05) on the ascorbic acid diet compared to the placebo and usual diet. Post-exercise FENO, LTC4–E4 and 9α, 11β-PGF2 concentration was significantly lower (p<0.05) on the ascorbic acid diet compared to the placebo and usual diet.ConclusionAscorbic acid supplementation provides a protective effect against exercise-induced airway narrowing in asthmatic subjects

Recent Developments in Peptide-Based Nucleic Acid Delivery

Despite the fact that non-viral nucleic acid delivery systems are generally considered to be less efficient than viral vectors, they have gained much interest in recent years due to their superior safety profile compared to their viral counterpart. Among these synthetic vectors are cationic polymers, branched dendrimers, cationic liposomes and cell-penetrating peptides (CPPs). The latter represent an assortment of fairly unrelated sequences essentially characterised by a high content of basic amino acids and a length of 10–30 residues. CPPs are capable of mediating the cellular uptake of hydrophilic macromolecules like peptides and nucleic acids (e.g. siRNAs, aptamers and antisense-oligonucleotides), which are internalised by cells at a very low rate when applied alone. Up to now, numerous sequences have been reported to show cell-penetrating properties and many of them have been used to successfully transport a variety of different cargos into mammalian cells. In recent years, it has become apparent that endocytosis is a major route of internalisation even though the mechanisms underlying the cellular translocation of CPPs are poorly understood and still subject to controversial discussions. In this review, we will summarise the latest developments in peptide-based cellular delivery of nucleic acid cargos. We will discuss different mechanisms of entry, the intracellular fate of the cargo, correlation studies of uptake versus biological activity of the cargo as well as technical problems and pitfalls

Global Transcriptome and Deletome Profiles of Yeast Exposed to Transition Metals

A variety of pathologies are associated with exposure to supraphysiological concentrations of essential metals and to non-essential metals and metalloids. The molecular mechanisms linking metal exposure to human pathologies have not been clearly defined. To address these gaps in our understanding of the molecular biology of transition metals, the genomic effects of exposure to Group IB (copper, silver), IIB (zinc, cadmium, mercury), VIA (chromium), and VB (arsenic) elements on the yeast Saccharomyces cerevisiae were examined. Two comprehensive sets of metal-responsive genomic profiles were generated following exposure to equi-toxic concentrations of metal: one that provides information on the transcriptional changes associated with metal exposure (transcriptome), and a second that provides information on the relationship between the expression of ∼4,700 non-essential genes and sensitivity to metal exposure (deletome). Approximately 22% of the genome was affected by exposure to at least one metal. Principal component and cluster analyses suggest that the chemical properties of the metal are major determinants in defining the expression profile. Furthermore, cells may have developed common or convergent regulatory mechanisms to accommodate metal exposure. The transcriptome and deletome had 22 genes in common, however, comparison between Gene Ontology biological processes for the two gene sets revealed that metal stress adaptation and detoxification categories were commonly enriched. Analysis of the transcriptome and deletome identified several evolutionarily conserved, signal transduction pathways that may be involved in regulating the responses to metal exposure. In this study, we identified genes and cognate signaling pathways that respond to exposure to essential and non-essential metals. In addition, genes that are essential for survival in the presence of these metals were identified. This information will contribute to our understanding of the molecular mechanism by which organisms respond to metal stress, and could lead to an understanding of the connection between environmental stress and signal transduction pathways

The issue of sexual violence against women in contemporary India.

India is often described to be a country with a fast growing economy and progressive indicators of human development. However, over the last decade there has been a growing concern of increased reporting of sexual violence in India which seems to contradict the first description. Therefore this creates a problem on how we can understand and explain this. The objective of this study is to try to gain a deeper understanding of some of the underlying factors of increased reporting of sexual violence in India, and to understand in what way the ‘modernization’ process possibly could be put in relation to this, something that is analyzed with help from Durkheim’s theory of anomie. This study draws on a qualitative desk study with a compilation of material from existing research on sexual violence against women, both at home and in public spaces. The findings were analyzed in relation to Durkheim’s theory of anomie and gender theories from two authors. The results show that some of the underlying factors for increased reports of sexual violence against women in India, like patriarchy, education and employment for women and gendered power inequalities are in a complex interplay. It was further seen as ‘traditional’ norms and values clashed with ‘modernity’ and caused these factors for violence. The outcome of the study showed that the increased reporting of sexual violence can be related to the ’modernization’ process both in a positive and negative way. Through Durkheim’s theory of anomie it was possible to see that ‘modernization’ could have caused a state of anomie, which has lead to deviant behavior and resulted in increased reporting of sexual violence against women

The Lewis score or the capsule endoscopy Crohn’s disease activity index: which one is better for the assessment of small bowel inflammation in established Crohn’s disease?

Background Small-bowel capsule endoscopy (CE) is a prime modality for evaluation of the small bowel. The Lewis score (LS) and the Capsule Endoscopy Crohn’s Disease Activity Index (CECDAI) are validated endoscopic indices for quantification of small-bowel inflammation on CE. It is unclear whether these indexes are interchangeable for the evaluation of mucosal inflammation in established Crohn’s disease (CD). The aim of this study was to compare the quantitative evaluation of small- bowel inflammation by LS and CECDAI. Methods Patients with known quiescent small-bowel CD for at least 3 months (Crohn’s disease activity index 9.2 corresponded to moderate-to-severe inflammation (LS ⩾ 790). There was a moderate correlation between capsule scores and FCP levels ( r = 0.39, p = 0.002 for LS, r = 0.48, p = 0.001 for C-LS, and r = 0.53, p = 0.001 for CECDAI, respectively). CRP levels were not significantly correlated with either score. Conclusions CECDAI and C-LS are strongly correlated and perform similarly for quantitative assessment of mucosal inflammation in established CD