301 research outputs found
Tuning Nanocrystal Surface Depletion by Controlling Dopant Distribution as a Route Toward Enhanced Film Conductivity
Electron conduction through bare metal oxide nanocrystal (NC) films is
hindered by surface depletion regions resulting from the presence of surface
states. We control the radial dopant distribution in tin-doped indium oxide
(ITO) NCs as a means to manipulate the NC depletion width. We find in films of
ITO NCs of equal overall dopant concentration that those with dopant-enriched
surfaces show decreased depletion width and increased conductivity. Variable
temperature conductivity data shows electron localization length increases and
associated depletion width decreases monotonically with increased density of
dopants near the NC surface. We calculate band profiles for NCs of differing
radial dopant distributions and, in agreement with variable temperature
conductivity fits, find NCs with dopant-enriched surfaces have narrower
depletion widths and longer localization lengths than those with
dopant-enriched cores. Following amelioration of NC surface depletion by atomic
layer deposition of alumina, all films of equal overall dopant concentration
have similar conductivity. Variable temperature conductivity measurements on
alumina-capped films indicate all films behave as granular metals. Herein, we
conclude that dopant-enriched surfaces decrease the near-surface depletion
region, which directly increases the electron localization length and
conductivity of NC films
Chelator free gallium-68 radiolabelling of silica coated iron oxide nanorods via surface interactions
The commercial availability of combined magnetic resonance imaging (MRI)/positron emission tomography (PET) scanners for clinical use has increased demand for easily prepared agents which offer signal or contrast in both modalities. Herein we describe a new class of silica coated iron–oxide nanorods (NRs) coated with polyethylene glycol (PEG) and/or a tetraazamacrocyclic chelator (DO3A). Studies of the coated NRs validate their composition and confirm their properties as in vivo T₂ MRI contrast agents. Radiolabelling studies with the positron emitting radioisotope gallium-68 (t1/2 = 68 min) demonstrate that, in the presence of the silica coating, the macrocyclic chelator was not required for preparation of highly stable radiometal-NR constructs. In vivo PET-CT and MR imaging studies show the expected high liver uptake of gallium-68 radiolabelled nanorods with no significant release of gallium-68 metal ions, validating our innovation to provide a novel simple method for labelling of iron oxide NRs with a radiometal in the absence of a chelating unit that can be used for high sensitivity liver imaging
Associations of NINJ2 sequence variants with incident ischemic stroke in the Cohorts for Heart and Aging in Genomic Epidemiology (CHARGE) consortium
Background<p></p>
Stroke, the leading neurologic cause of death and disability, has a substantial genetic component. We previously conducted a genome-wide association study (GWAS) in four prospective studies from the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium and demonstrated that sequence variants near the NINJ2 gene are associated with incident ischemic stroke. Here, we sought to fine-map functional variants in the region and evaluate the contribution of rare variants to ischemic stroke risk.<p></p>
Methods and Results<p></p>
We sequenced 196 kb around NINJ2 on chromosome 12p13 among 3,986 European ancestry participants, including 475 ischemic stroke cases, from the Atherosclerosis Risk in Communities Study, Cardiovascular Health Study, and Framingham Heart Study. Meta-analyses of single-variant tests for 425 common variants (minor allele frequency [MAF] ≥ 1%) confirmed the original GWAS results and identified an independent intronic variant, rs34166160 (MAF = 0.012), most significantly associated with incident ischemic stroke (HR = 1.80, p = 0.0003). Aggregating 278 putatively-functional variants with MAF≤ 1% using count statistics, we observed a nominally statistically significant association, with the burden of rare NINJ2 variants contributing to decreased ischemic stroke incidence (HR = 0.81; p = 0.026).<p></p>
Conclusion<p></p>
Common and rare variants in the NINJ2 region were nominally associated with incident ischemic stroke among a subset of CHARGE participants. Allelic heterogeneity at this locus, caused by multiple rare, low frequency, and common variants with disparate effects on risk, may explain the difficulties in replicating the original GWAS results. Additional studies that take into account the complex allelic architecture at this locus are needed to confirm these findings
LPS from P. gingivalis
Objective. Oral inflammatory pathologies are linked to increased oxidative stress, thereby partly explaining their relevance in the etiology of systemic disorders. The purpose of this work was to determine the degree to which LPS from Porphyromonas gingivalis, the primary pathogen related to oral inflammation, altered gingival mitochondrial function and reactive oxygen species generation. Methods. Human gingival fibroblast (HGF-1) cells were treated with lipopolysaccharide of P. gingivalis. Mitochondrial function was determined via high-resolution respirometry. Results. LPS-treated HGF-1 cells had significantly higher mitochondrial complex IV and higher rates of mitochondrial respiration. However, this failed to translate into greater ATP production, as ATP production was paradoxically diminished with LPS treatment. Nevertheless, production of the reactive H2O2 was elevated with LPS treatment. Conclusions. LPS elicits an increase in gingival cell mitochondria content, with a subsequent increase in reactive oxygen species production (i.e., H2O2), despite a paradoxical reduction in ATP generation. These findings provide an insight into the nature of oxidative stress in oral inflammatory pathologies
Recommended from our members
Multiomics modeling of the immunome, transcriptome, microbiome, proteome and metabolome adaptations during human pregnancy.
MotivationMultiple biological clocks govern a healthy pregnancy. These biological mechanisms produce immunologic, metabolomic, proteomic, genomic and microbiomic adaptations during the course of pregnancy. Modeling the chronology of these adaptations during full-term pregnancy provides the frameworks for future studies examining deviations implicated in pregnancy-related pathologies including preterm birth and preeclampsia.ResultsWe performed a multiomics analysis of 51 samples from 17 pregnant women, delivering at term. The datasets included measurements from the immunome, transcriptome, microbiome, proteome and metabolome of samples obtained simultaneously from the same patients. Multivariate predictive modeling using the Elastic Net (EN) algorithm was used to measure the ability of each dataset to predict gestational age. Using stacked generalization, these datasets were combined into a single model. This model not only significantly increased predictive power by combining all datasets, but also revealed novel interactions between different biological modalities. Future work includes expansion of the cohort to preterm-enriched populations and in vivo analysis of immune-modulating interventions based on the mechanisms identified.Availability and implementationDatasets and scripts for reproduction of results are available through: https://nalab.stanford.edu/multiomics-pregnancy/.Supplementary informationSupplementary data are available at Bioinformatics online
Genome sequence of an Australian kangaroo, Macropus eugenii, provides insight into the evolution of mammalian reproduction and development.
BACKGROUND: We present the genome sequence of the tammar wallaby, Macropus eugenii, which is a member of the kangaroo family and the first representative of the iconic hopping mammals that symbolize Australia to be sequenced. The tammar has many unusual biological characteristics, including the longest period of embryonic diapause of any mammal, extremely synchronized seasonal breeding and prolonged and sophisticated lactation within a well-defined pouch. Like other marsupials, it gives birth to highly altricial young, and has a small number of very large chromosomes, making it a valuable model for genomics, reproduction and development. RESULTS: The genome has been sequenced to 2 × coverage using Sanger sequencing, enhanced with additional next generation sequencing and the integration of extensive physical and linkage maps to build the genome assembly. We also sequenced the tammar transcriptome across many tissues and developmental time points. Our analyses of these data shed light on mammalian reproduction, development and genome evolution: there is innovation in reproductive and lactational genes, rapid evolution of germ cell genes, and incomplete, locus-specific X inactivation. We also observe novel retrotransposons and a highly rearranged major histocompatibility complex, with many class I genes located outside the complex. Novel microRNAs in the tammar HOX clusters uncover new potential mammalian HOX regulatory elements. CONCLUSIONS: Analyses of these resources enhance our understanding of marsupial gene evolution, identify marsupial-specific conserved non-coding elements and critical genes across a range of biological systems, including reproduction, development and immunity, and provide new insight into marsupial and mammalian biology and genome evolution
Pulmonary Hypertension in Patients With COPD : Results From the Comparative, Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension (COMPERA)
Funding Information: FUNDING/SUPPORT: This work was supported by the German Center of Lung Research (DZL). COMPERA is funded by unrestricted grants from Acceleron , Actelion Pharmaceuticals , Bayer , OMT , and GSK . Funding Information: Financial/nonfinancial disclosures: The authors have reported to CHEST the following: C. D. V. has received fees for serving as a speaker, consultant, and an advisory board member from the following companies: Acceleron, Actelion, Bayer, Dompè, GSK, Janssen, MSD, Pfizer, and United Therapeutics. M. M. H. has received speaker fees, honoraria, or both for consultations from Acceleron, Actelion, Bayer, Janssen, MSD, and Pfizer. D. H. has received travel compensation from Actelion, Boehringer-Ingelheim, and Shire. D. P. has received fees for consultations from Actelion, Aspen, Biogen, Bayer, Boehringer Ingelheim, Johnson & Johnson, Novartis, Daiichi Sankyo, Sanofi, and Pfizer. N. B. received speaker fees from Bayer/MSD and Actelion/Janssen. K. M. O. has received speaker fees from Actelion, Bayer, and Lilly. H. A. G. has received honorariums for consultations, speaking at conferences, or both from Bayer HealthCare AG, Actelion, Encysive, Pfizer, Ergonex, Lilly, and Novartis. He is member of advisory boards for Bayer HealthCare AG, Pfizer, GSK, Actelion, Lilly, Merck, Encysive, and Ergonex. He also has received governmental grants from the German Research Foundation (DFG), Excellence Cluster Cardiopulmonary Research (ECCPS), State Government of Hessen (LOEWE), and the German Ministry for Education and Research (BMBF). M. Held has received speaker fees and honoraria for consultations from Actelion, Bayer, Boehringer Ingelheim Pharma, Encysive, Glaxo Smith Kline, Lilly, Janssen, Novartis, Pfizer, Nycomed, Roche, and Servier. H. K. has received speaker fees and honoraria for consultations from Actelion, Bayer, GSK, Lilly, Novartis, Pfizer, and United Therapeutics and research grants from Actelion. T. J. L. has received speaker fees, honoraria for consultations, and research funding from Actelion, Acceleron Pharma, Bayer, GSK, Janssen-Cilag, MSD, and Pfizer. S. R. has received honoraria for lectures, consultancy, or both from Actavis, Actelion, Bayer, GSK, Lilly, Novartis, Pfizer, and United Therapeutics. D. D. declares honoraria for lectures, consultancy, or both from Actelion, Bayer, GSK, Novartis, Pfizer, and Servier; participation in clinical trials for Actelion, Bayer, GSK, and Novartis; and research support to his institution from Actelion. R. B. has received fees from GSK, UT, Dompè, Bayer, Ferrer, MSD, and AOP Orphan Pharmaceuticals. M. C. has received fees for consulting from GSK and speaker fees from Bayer and Pfizer. M. Halank has received speaker fees and/or honoraria for consultations from Acceleron, Actelion, AstraZeneca, Bayer, BayerChemie, GSK, Janssen, MSD and Novartis. A. V.-N. reports receiving lecture fees from Actelion, Bayer, GlaxoSmithKline, Lilly, and Pfizer; serves on the advisory board of Actelion and Bayer; and serves on steering committees for Actelion, Bayer, GlaxoSmithKline, and Pfizer. D. S. received fees for lectures, consulting, research support, or a combination thereof to his institution from Actelion, Bayer, GSK, and Pfizer. R. E. has received speaker fees and honoraria for consultations from Actelion, Bayer, GSK, Lilly, Novartis, Pfizer, and United Therapeutics. J. S. R. G. has received speaker fees and honoraria for consultations from Acceleron, Actelion, Bayer, Complexa, GSK, MSD, Pfizer, and United Therapeutics. M. D. has received investigator, speaker, consultant, or steering committee member fees from Actelion, Aventis Pharmaceuticals, Bayer, Eli Lilly, Encysive, Gilead (Myogen), GlaxoSmithKline, Nippon Shyniaku, Novartis, Pfizer, Schering, and United Therapeutics; educational grants from Actelion, GlaxoSmithKline, Pfizer, and Therabel; and research grants from Actelion, Pfizer, and GlaxoSmithKline. She is holder of the Actelion Chair for Pulmonary Hypertension and of the GSK chair for research and education in pulmonary vascular pathology at the Catholic University of Leuven. J. C. has received fees for consultancies and lectures from Actelion, Bayer, GSK, United Therapeutics, and Pfizer as well as equipment and educational grants from Actelion. C. O. has received speaker fees and honoraria for consultations from Actelion, Bayer, GSK, Lilly, Novartis, and Pfizer. H. K. has received honoraria for lectures, consultancy, or both from Actelion-Janssen, Amicus Therapeutics, and Bristol Meyers Squibb. O. D. has or had consultancy relationships, has received research funding (last 3 years), or both from AbbVie, Actelion, Acceleron Pharma, Amgen, AnaMar, Baecon Discovery, Blade Therapeutics, Bayer, Boehringer Ingelheim, Catenion, Competitive Corpus, Drug Development International Ltd, CSL Behring, ChemomAb, Ergonex, Galapagos NV, Glenmark Pharmaceuticals, GSK, Horizon (Curzion) Pharmaceuticals, Inventiva, Italfarmaco, iQone, iQvia, Kymera Therapeutics, Lilly, medac, Medscape, Mitsubishi Tanabe Pharma, MSD, Novartis, Pfizer, Roche, Sanofi, Target Bio Science, and UCB in the area of potential treatments of scleroderma and its complications including PH. In addition, he has a patent mir-29 for the treatment of systemic sclerosis issued (US8247389, EP2331143). E. G. has received honoraria for consultations, speaking at conferences, or both from Bayer/MSD, Actelion/Janssen, GWT-TUD, and OMT/United Therapeutics. None declared (A. S.). Publisher Copyright: © 2021 The AuthorsBackground: Pulmonary hypertension (PH) in COPD is a poorly investigated clinical condition. Research Question: Which factors determine the outcome of PH in COPD? Study Design and Methods: We analyzed the characteristics and outcome of patients enrolled in the Comparative, Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension (COMPERA) with moderate or severe PH in COPD as defined during the 6th PH World Symposium who received medical therapy for PH and compared them with patients with idiopathic pulmonary arterial hypertension (IPAH). Results: The population included incident patients with moderate PH in COPD (n = 68), with severe PH in COPD (n = 307), and with IPAH (n = 489). Patients with PH in COPD were older, predominantly male, and treated mainly with phosphodiesterase-5 inhibitors. Despite similar hemodynamic impairment, patients with PH in COPD achieved a worse 6-min walking distance (6MWD) and showed a more advanced World Health Organization functional class (WHO FC). Transplant-free survival rates at 1, 3, and 5 years were higher in the IPAH group than in the PH in COPD group (IPAH: 94%, 75%, and 55% vs PH in COPD: 86%, 55%, and 38%; P = .004). Risk factors for poor outcomes in PH in COPD were male sex, low 6MWD, and high pulmonary vascular resistance (PVR). In patients with severe PH in COPD, improvements in 6MWD by ≥ 30 m or improvements in WHO FC after initiation of medical therapy were associated with better outcomes. Interpretation: Patients with PH in COPD were functionally more impaired and had a poorer outcome than patients with IPAH. Predictors of death in the PH in COPD group were sex, 6MWD, and PVR. Our data raise the hypothesis that some patients with severe PH in COPD may benefit from PH treatment. Randomized controlled studies are necessary to explore this hypothesis further. Trial Registry: ClinicalTrials.gov; No.: NCT01347216; URL: www.clinicaltrials.govpublishersversionPeer reviewe
Recommended from our members
Patterns of leisure-time physical activity across pregnancy and adverse pregnancy outcomes
Background
Although leisure-time physical activity (PA) contributes to overall health, including pregnancy health, patterns across pregnancy have not been related to birth outcomes. We hypothesized that women with sustained low leisure-time PA would have excess risk of adverse pregnancy outcomes, and that changing patterns across pregnancy (high to low and low to high) may also be related to risk of adverse pregnancy outcomes.
Methods
Nulliparous women (n = 10,038) were enrolled at 8 centers early in pregnancy (mean gestational age in weeks [SD] = 12.05 [1.51]. Frequency, duration, and intensity (metabolic equivalents) of up to three leisure activities reported in the first, second and third trimesters were analyzed. Growth mixture modeling was used to identify leisure-time PA patterns across pregnancy. Adverse pregnancy outcomes (preterm birth, [PTB, overall and spontaneous], hypertensive disorders of pregnancy [HDP], gestational diabetes [GDM] and small-for-gestational-age births [SGA]) were assessed via chart abstraction.
Results
Five patterns of leisure-time PA across pregnancy were identified: High (35%), low (18%), late decreasing (24%), early decreasing (10%), and early increasing (13%). Women with sustained low leisure-time PA were younger and more likely to be black or Hispanic, obese, or to have smoked prior to pregnancy. Women with low vs. high leisure-time PA patterns had higher rates of PTB (10.4 vs. 7.5), HDP (13.9 vs. 11.4), and GDM (5.7 vs. 3.1, all p < 0.05). After adjusting for maternal factors (age, race/ethnicity, BMI and smoking), the risk of GDM (Odds ratio 2.00 [95% CI 1.47, 2.73]) remained higher in women with low compared to high patterns. Early and late decreasing leisure-time PA patterns were also associated with higher rates of GDM. In contrast, women with early increasing patterns had rates of GDM similar to the group with high leisure-time PA (3.8% vs. 3.1%, adjusted OR 1.16 [0.81, 1.68]). Adjusted risk of overall PTB (1.31 [1.05, 1.63]) was higher in the low pattern group, but spontaneous PTB, HDP and SGA were not associated with leisure-time PA patterns.
Conclusions
Sustained low leisure-time PA across pregnancy is associated with excess risk of GDM and overall PTB compared to high patterns in nulliparous women. Women with increased leisure-time PA early in pregnancy had low rates of GDM that were similar to women with high patterns, raising the possibility that early pregnancy increases in activity may be associated with improved pregnancy health.
Trial registration
Registration number
NCT02231398
Lateral flow test engineering and lessons learned from COVID-19
The acceptability and feasibility of large-scale testing with lateral flow tests (LFTs) for clinical and public health purposes has been demonstrated during the COVID-19 pandemic. LFTs can detect analytes in a variety of samples, providing a rapid read-out, which allows self-testing and decentralized diagnosis. In this Review, we examine the changing LFT landscape with a focus on lessons learned from COVID-19. We discuss the implications of LFTs for decentralized testing of infectious diseases, including diseases of epidemic potential, the ‘silent pandemic’ of antimicrobial resistance, and other acute and chronic infections. Bioengineering approaches will play a key part in increasing the sensitivity and specificity of LFTs, improving sample preparation, incorporating nucleic acid amplification and detection, and enabling multiplexing, digital connection and green manufacturing, with the aim of creating the next generation of high-accuracy, easy-to-use, affordable and digitally connected LFTs. We conclude with recommendations, including the building of a global network of LFT research and development hubs to facilitate and strengthen future diagnostic resilience
Monte Carlo Methods for Estimating Interfacial Free Energies and Line Tensions
Excess contributions to the free energy due to interfaces occur for many
problems encountered in the statistical physics of condensed matter when
coexistence between different phases is possible (e.g. wetting phenomena,
nucleation, crystal growth, etc.). This article reviews two methods to estimate
both interfacial free energies and line tensions by Monte Carlo simulations of
simple models, (e.g. the Ising model, a symmetrical binary Lennard-Jones fluid
exhibiting a miscibility gap, and a simple Lennard-Jones fluid). One method is
based on thermodynamic integration. This method is useful to study flat and
inclined interfaces for Ising lattices, allowing also the estimation of line
tensions of three-phase contact lines, when the interfaces meet walls (where
"surface fields" may act). A generalization to off-lattice systems is described
as well.
The second method is based on the sampling of the order parameter
distribution of the system throughout the two-phase coexistence region of the
model. Both the interface free energies of flat interfaces and of (spherical or
cylindrical) droplets (or bubbles) can be estimated, including also systems
with walls, where sphere-cap shaped wall-attached droplets occur. The
curvature-dependence of the interfacial free energy is discussed, and estimates
for the line tensions are compared to results from the thermodynamic
integration method. Basic limitations of all these methods are critically
discussed, and an outlook on other approaches is given
- …