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Connecting defects and amorphization in UiO-66 and MIL-140 metal-organic frameworks: a combined experimental and computational study.
The mechanism and products of the structural collapse of the metal-organic frameworks (MOFs) , and upon ball-milling are investigated through solid state (13)C NMR and pair distribution function (PDF) studies, finding amorphization to proceed by the breaking of a fraction of metal-ligand bonding in each case. The amorphous products contain inorganic-organic bonding motifs reminiscent of the crystalline phases. Whilst the inorganic Zr6O4(OH)4 clusters of remain intact upon structural collapse, the ZrO backbone of the frameworks undergoes substantial distortion. Density functional theory calculations have been performed to investigate defective models of and show, through comparison of calculated and experimental (13)C NMR spectra, that amorphization and defects in the materials are linked.The manuscript was written through contributions of all authors. TDB conceived the initial project. T.D.B. acknowledges Trinity Hall (University of Cambridge) and Professor Anthony K. Cheetham for use of lab facilities. D.G.R. acknowledges the UK MRC for financial support. The authors acknowledge Diamond Light Source for the provision of synchrotron access to Beamline I15 (ex p. EE9691) and Philip A. Chater and Andrew Cairns for assistance with data collection. T.K.T. and C.M.D. thank the French National Research Agency (ANR project: HOPFAME ANR-13-BS07-0002-01) and the Foundation de l'Orangerie for funding. The calculations have been performed using the HPC resources from GENCI (CINES/TGCC/IDRIS) through Grant (2015-097343 and -091461). B.B., B.V.d.V. and D.D.V . gratefully acknowledge the FWO for funding (aspirant grant).This is the final version of the article. It was first available from the Royal Society of Chemistry via http://dx.doi.org/10.1039/C5CP06798
Sinter formation during directed energy deposition of titanium alloy powders
During directed energy deposition (DED) additive manufacturing, powder agglomeration and sintering can occur outside of the melt pool when using titanium alloy powders. Using in situ synchrotron radiography we investigate the mechanisms by which sintering of Ti6242 powder occurs around the pool, performing a parametric study to determine the influence of laser power and stage traverse speed on sinter build-up. The results reveal that detrimental sinter can be reduced using a high laser power or increased stage traverse speed, although the latter also reduces deposition layer thickness. The mechanism of sinter formation during DED was determined to be in-flight heating of the powder particles in the laser beam. Calculations of particle heating under the processing conditions explored in this study confirm that powder particles can reasonably exceed 700 °C, the threshold for Ti surface oxide dissolution, and thus the powder is prone to sintering if not incorporated into the melt pool. The build-up of sinter powder layer on deposit surfaces led to lack of fusion pores. To mitigate sinter formation and its detrimental effects on DED component quality, it is essential that the powder delivery spot area is smaller than the melt pool, ensuring most powder lands in the melt pool
The neurogenic basic helix–loop–helix transcription factor NeuroD6 confers tolerance to oxidative stress by triggering an antioxidant response and sustaining the mitochondrial biomass
Preserving mitochondrial mass, bioenergetic functions and ROS (reactive oxygen species) homoeostasis is key to neuronal differentiation and survival, as mitochondria produce most of the energy in the form of ATP to execute and maintain these cellular processes. In view of our previous studies showing that NeuroD6 promotes neuronal differentiation and survival on trophic factor withdrawal, combined with its ability to stimulate the mitochondrial biomass and to trigger comprehensive antiapoptotic and molecular chaperone responses, we investigated whether NeuroD6 could concomitantly modulate the mitochondrial biomass and ROS homoeostasis on oxidative stress mediated by serum deprivation. In the present study, we report a novel role of NeuroD6 as a regulator of ROS homoeostasis, resulting in enhanced tolerance to oxidative stress. Using a combination of flow cytometry, confocal fluorescence microscopy and mitochondrial fractionation, we found that NeuroD6 sustains mitochondrial mass, intracellular ATP levels and expression of specific subunits of respiratory complexes upon oxidative stress triggered by withdrawal of trophic factors. NeuroD6 also maintains the expression of nuclear-encoded transcription factors, known to regulate mitochondrial biogenesis, such as PGC-1α (peroxisome-proliferator-activated receptor γ co-activator-1α), Tfam (transcription factor A, mitochondrial) and NRF-1 (nuclear respiratory factor-1). Finally, NeuroD6 triggers a comprehensive antioxidant response to endow PC12-ND6 cells with intracellular ROS scavenging capacity. The NeuroD6 effect is not limited to the classic induction of the ROS-scavenging enzymes, such as SOD2 (superoxide dismutase 2), GPx1 (glutathione peroxidase 1) and PRDX5 (peroxiredoxin 5), but also to the recently identified powerful ROS suppressors PGC-1α, PINK1 (phosphatase and tensin homologue-induced kinase 1) and SIRT1. Thus our collective results support the concept that the NeuroD6–PGC-1α–SIRT1 neuroprotective axis may be critical in co-ordinating the mitochondrial biomass with the antioxidant reserve to confer tolerance to oxidative stress
Using linear and natural cubic splines, SITAR, and latent trajectory models to characterise nonlinear longitudinal growth trajectories in cohort studies
BACKGROUND: Longitudinal data analysis can improve our understanding of the influences on health trajectories across the life-course. There are a variety of statistical models which can be used, and their fitting and interpretation can be complex, particularly where there is a nonlinear trajectory. Our aim was to provide an accessible guide along with applied examples to using four sophisticated modelling procedures for describing nonlinear growth trajectories. METHODS: This expository paper provides an illustrative guide to summarising nonlinear growth trajectories for repeatedly measured continuous outcomes using (i) linear spline and (ii) natural cubic spline linear mixed-effects (LME) models, (iii) Super Imposition by Translation and Rotation (SITAR) nonlinear mixed effects models, and (iv) latent trajectory models. The underlying model for each approach, their similarities and differences, and their advantages and disadvantages are described. Their application and correct interpretation of their results is illustrated by analysing repeated bone mass measures to characterise bone growth patterns and their sex differences in three cohort studies from the UK, USA, and Canada comprising 8500 individuals and 37,000 measurements from ages 5-40 years. Recommendations for choosing a modelling approach are provided along with a discussion and signposting on further modelling extensions for analysing trajectory exposures and outcomes, and multiple cohorts. RESULTS: Linear and natural cubic spline LME models and SITAR provided similar summary of the mean bone growth trajectory and growth velocity, and the sex differences in growth patterns. Growth velocity (in grams/year) peaked during adolescence, and peaked earlier in females than males e.g., mean age at peak bone mineral content accrual from multicohort SITAR models was 12.2 years in females and 13.9 years in males. Latent trajectory models (with trajectory shapes estimated using a natural cubic spline) identified up to four subgroups of individuals with distinct trajectories throughout adolescence. CONCLUSIONS: LME models with linear and natural cubic splines, SITAR, and latent trajectory models are useful for describing nonlinear growth trajectories, and these methods can be adapted for other complex traits. Choice of method depends on the research aims, complexity of the trajectory, and available data. Scripts and synthetic datasets are provided for readers to replicate trajectory modelling and visualisation using the R statistical computing software
Design and rationale of a multi-center, pragmatic, open-label randomized trial of antimicrobial therapy - the study of clinical efficacy of antimicrobial therapy strategy using pragmatic design in Idiopathic Pulmonary Fibrosis (CleanUP-IPF) clinical trial
Compelling data have linked disease progression in patients with idiopathic pulmonary fibrosis (IPF) with lung dysbiosis and the resulting dysregulated local and systemic immune response. Moreover, prior therapeutic trials have suggested improved outcomes in these patients treated with either sulfamethoxazole/ trimethoprim or doxycycline. These trials have been limited by methodological concerns. This trial addresses the primary hypothesis that long-term treatment with antimicrobial therapy increases the time-to-event endpoint of respiratory hospitalization or all-cause mortality compared to usual care treatment in patients with IPF. We invoke numerous innovative features to achieve this goal, including: 1) utilizing a pragmatic randomized trial design; 2) collecting targeted biological samples to allow future exploration of 'personalized' therapy; and 3) developing a strong partnership between the NHLBI, a broad range of investigators, industry, and philanthropic organizations. The trial will randomize approximately 500 individuals in a 1:1 ratio to either antimicrobial therapy or usual care. The site principal investigator will declare their preferred initial antimicrobial treatment strategy (trimethoprim 160 mg/ sulfamethoxazole 800 mg twice a day plus folic acid 5 mg daily or doxycycline 100 mg once daily if body weight is < 50 kg or 100 mg twice daily if ≥50 kg) for the participant prior to randomization. Participants randomized to antimicrobial therapy will receive a voucher to help cover the additional prescription drug costs. Additionally, those participants will have 4-5 scheduled blood draws over the initial 24 months of therapy for safety monitoring. Blood sampling for DNA sequencing and genome wide transcriptomics will be collected before therapy. Blood sampling for transcriptomics and oral and fecal swabs for determination of the microbiome communities will be collected before and after study completion. As a pragmatic study, participants in both treatment arms will have limited in-person visits with the enrolling clinical center. Visits are limited to assessments of lung function and other clinical parameters at time points prior to randomization and at months 12, 24, and 36. All participants will be followed until the study completion for the assessment of clinical endpoints related to hospitalization and mortality events. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT02759120
Chronic inflammatory arthritis drives systemic changes in circadian energy metabolism
SignificanceRheumatoid arthritis (RA) is a debilitating chronic inflammatory disease in which symptoms exhibit a strong time-of-day rhythmicity. RA is commonly associated with metabolic disturbance and increased incidence of diabetes and cardiovascular disease, yet the mechanisms underlying this metabolic dysregulation remain unclear. Here, we demonstrate that rhythmic inflammation drives reorganization of metabolic programs in distal liver and muscle tissues. Chronic inflammation leads to mitochondrial dysfunction and dysregulation of fatty acid metabolism, including accumulation of inflammation-associated ceramide species in a time-of-day-dependent manner. These findings reveal multiple points for therapeutic intervention centered on the circadian clock, metabolic dysregulation, and inflammatory signaling
Intra- and inter-observer analysis in the morphological assessment of early-stage embryos
<p>Abstract</p> <p>Background</p> <p>The aim of this study was to determine the intra- and inter-observer variability in the evaluation of embryo quality. Multilevel images of embryos on day 1, day 2 and day 3, were analysed using different morphological parameters.</p> <p>Methods</p> <p>Multilevel images of embryos on day 1, day 2 and day 3, were analysed using a standard scoring system. The kappa coefficient was calculated to measure intra- and inter-observer variability before and after training sessions.</p> <p>Results</p> <p>Good to excellent intra-observer agreement was present for most parameters exceptions being scoring the position of pronuclei and the presence of a cytoplasmic halo on day 1, multinucleation on day 2 and the size of fragments on day 3. Inter-observer agreement was only good to excellent for the number of blastomeres on day 2 and day 3 and the orientation of the cleavage axes on day 2. Training sessions had a positive impact on inter-observer agreement.</p> <p>Conclusion</p> <p>In conclusion, assessment of morphological characteristics of early stage embryos using multilevel images was marked by a high intra-observer and a moderate inter-observer agreement. Training sessions were useful to increase inter-observer agreement.</p
A molecular insight into algal-oomycete warfare : cDNA analysis of Ectocarpus siliculosus infected with the basal oomycete Eurychasma dicksonii
Peer reviewedPublisher PD
Protecting children from secondhand smoke: a mixed-methods feasibility study of a novel smoke-free home intervention
Background: Globally, 40 % of children under 14 years are regularly exposed to secondhand smoke (SHS), typically in their homes. There is limited evidence of the effectiveness of interventions to reduce children’s SHS exposure,and so the aim of this study was to test the feasibility and acceptability of a novel intervention to help parents and carers (caregivers) to reduce their children’s exposure to SHS at home.
Methods: A novel multi-component intervention to support caregivers to reduce their children’s SHS exposure athome was tested in a two-phase feasibility study. The 12-week intensive intervention delivered in the homeconsisted of three components: behavioural support, nicotine replacement therapy (NRT) for temporary abstinenceand feedback on levels of SHS exposure in the form of children’s salivary cotinine (phase 1) or home air quality (PM2.5) (phase 2). Participants were caregivers who smoked inside their homes and had at least one child under the age of 5 years living with them the majority of the time. Mixed-methods were used to explore the acceptability and feasibility of the intervention as well as processes, particularly around recruitment and retention, for an exploratory efficacy trial.
Results: Twelve caregivers completed the study, all received personalised feedback on SHS exposure and behavioural support to help them to make their homes smoke-free and the majority at least tried NRT. Saliva cotinine results were variable in phase 1, and therefore, measures of PM2.5 were used for feedback in phase 2.Behavioural support was well received with personalised feedback reported as being the key motivator for initiating and maintaining behaviour change.
Conclusions: Recruiting disadvantaged caregivers was labour intensive, but once recruited, this novel intervention was both feasible and acceptable in supporting caregivers to reduce their children’s exposure to SHS at home. It is appropriate to test the efficacy of this novel intervention in an exploratory randomised controlled trial
Effects of Anti-VEGF on Predicted Antibody Biodistribution: Roles of Vascular Volume, Interstitial Volume, and Blood Flow
BACKGROUND: The identification of clinically meaningful and predictive models of disposition kinetics for cancer therapeutics is an ongoing pursuit in drug development. In particular, the growing interest in preclinical evaluation of anti-angiogenic agents alone or in combination with other drugs requires a complete understanding of the associated physiological consequences. METHODOLOGY/PRINCIPAL FINDINGS: Technescan™ PYP™, a clinically utilized radiopharmaceutical, was used to measure tissue vascular volumes in beige nude mice that were naïve or administered a single intravenous bolus dose of a murine anti-vascular endothelial growth factor (anti-VEGF) antibody (10 mg/kg) 24 h prior to assay. Anti-VEGF had no significant effect (p>0.05) on the fractional vascular volumes of any tissues studied; these findings were further supported by single photon emission computed tomographic imaging. In addition, apart from a borderline significant increase (p = 0.048) in mean hepatic blood flow, no significant anti-VEGF-induced differences were observed (p>0.05) in two additional physiological parameters, interstitial fluid volume and the organ blood flow rate, measured using indium-111-pentetate and rubidium-86 chloride, respectively. Areas under the concentration-time curves generated by a physiologically-based pharmacokinetic model changed substantially (>25%) in several tissues when model parameters describing compartmental volumes and blood flow rates were switched from literature to our experimentally derived values. However, negligible changes in predicted tissue exposure were observed when comparing simulations based on parameters measured in naïve versus anti-VEGF-administered mice. CONCLUSIONS/SIGNIFICANCE: These observations may foster an enhanced understanding of anti-VEGF effects in murine tissues and, in particular, may be useful in modeling antibody uptake alone or in combination with anti-VEGF
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