1,054 research outputs found
Effect of Shear on Performance and Microbial Ecology of Continuously Stirred Anaerobic Digesters Treating Animal Manure
We Determined the Effect of Different Mixing Intensities on the Performance, Methanogenic Population Dynamics, and Juxtaposition of Syntrophic Microbes in Anaerobic Digesters Treating Cow Manure from a Dairy Farm. Computer Automated Radioactive Particle Tracking in Conjunction with Computational Fluid Dynamics Was Performed to Quantify the Shear Levels Locally. Four Continuously Stirred Anaerobic Digesters Were Operated at Different Mixing Intensities of 1,500, 500, 250, and 50 Revolutions Per Min (RPM) over a 260-Day Period at a Temperature of 34 ± 1°C. Animal Manure at a Volatile Solids (VS) Concentration of 50 G/L Was Fed into the Digesters Daily at Five Different Organic Loading Rates between 0.6 and 3.5 G vs./L Day. the Different Mixing Intensities Had No Effect on the Biogas Production Rates and Yields at Steady-State Conditions. a Methane Yield of 0.241 ± 0.007 L CH 4/g vs. Fed Was Obtained by Pooling the Data of All Four Digesters during Steady-State Periods. However, Digester Performance Was Affected Negatively by Mixing Intensity during Startup of the Digesters, with Lower Biogas Production Rates and Higher Volatile Fatty Acids Concentrations Observed for the 1,500-RPM Digester. Despite Similar Methane Production Yields and Rates, the Acetoclastic Methanogenic Populations Were Different for the High- and Low-Intensity Mixed Digesters with Methanosarcina Spp. and Methanosaeta Concilii as the Predominant Methanogens, Respectively. for All Four Digesters, Epifluorescence Microscopy Revealed Decreasing Microbial Floc Sizes Beginning at Week 4 and Continuing through Week 26 after Which No Microbial Flocs Remained. This Decrease in Size, and Subsequent Loss of Microbial Flocs Did Not, However, Produce Any Long-Term Upsets in Digester Performance. © 2007 Wiley Periodicals, Inc
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In utero ultrafine particulate matter exposure causes offspring pulmonary immunosuppression.
Early life exposure to fine particulate matter (PM) in air is associated with infant respiratory disease and childhood asthma, but limited epidemiological data exist concerning the impacts of ultrafine particles (UFPs) on the etiology of childhood respiratory disease. Specifically, the role of UFPs in amplifying Th2- and/or Th17-driven inflammation (asthma promotion) or suppressing effector T cells (increased susceptibility to respiratory infection) remains unclear. Using a mouse model of in utero UFP exposure, we determined early immunological responses to house dust mite (HDM) allergen in offspring challenged from 0 to 4 wk of age. Two mice strains were exposed throughout gestation: C57BL/6 (sensitive to oxidative stress) and BALB/C (sensitive to allergen exposure). Offspring exposed to UFPs in utero exhibited reduced inflammatory response to HDM. Compared with filtered air (FA)-exposed/HDM-challenged mice, UFP-exposed offspring had lower white blood cell counts in bronchoalveolar lavage fluid and less pronounced peribronchiolar inflammation in both strains, albeit more apparent in C57BL/6 mice. In the C57BL/6 strain, offspring exposed in utero to FA and challenged with HDM exhibited a robust response in inflammatory cytokines IL-13 and Il-17. In contrast, this response was lost in offspring exposed in utero to UFPs. Circulating IL-10 was significantly up-regulated in C57BL/6 offspring exposed to UFPs, suggesting increased regulatory T cell expression and suppressed Th2/Th17 response. Our results reveal that in utero UFP exposure at a level close to the WHO recommended PM guideline suppresses an early immune response to HDM allergen, likely predisposing neonates to respiratory infection and altering long-term pulmonary health
High-repetition-rate and high-photon-flux 70 eV high-harmonic source for coincidence ion imaging of gas-phase molecules
Unraveling and controlling chemical dynamics requires techniques to image
structural changes of molecules with femtosecond temporal and picometer spatial
resolution. Ultrashort-pulse x-ray free-electron lasers have significantly
advanced the field by enabling advanced pump-probe schemes. There is an
increasing interest in using table-top photon sources enabled by high-harmonic
generation of ultrashort-pulse lasers for such studies. We present a novel
high-harmonic source driven by a 100 kHz fiber laser system, which delivers
10 photons/s in a single 1.3 eV bandwidth harmonic at 68.6 eV. The
combination of record-high photon flux and high repetition rate paves the way
for time-resolved studies of the dissociation dynamics of inner-shell ionized
molecules in a coincidence detection scheme. First coincidence measurements on
CHI are shown and it is outlined how the anticipated advancement of fiber
laser technology and improved sample delivery will, in the next step, allow
pump-probe studies of ultrafast molecular dynamics with table-top XUV-photon
sources. These table-top sources can provide significantly higher repetition
rates than the currently operating free-electron lasers and they offer very
high temporal resolution due to the intrinsically small timing jitter between
pump and probe pulses
Deficient methylation and formylation of mt-tRNA(Met) wobble cytosine in a patient carrying mutations in NSUN3.
Epitranscriptome modifications are required for structure and function of RNA and defects in these pathways have been associated with human disease. Here we identify the RNA target for the previously uncharacterized 5-methylcytosine (m(5)C) methyltransferase NSun3 and link m(5)C RNA modifications with energy metabolism. Using whole-exome sequencing, we identified loss-of-function mutations in NSUN3 in a patient presenting with combined mitochondrial respiratory chain complex deficiency. Patient-derived fibroblasts exhibit severe defects in mitochondrial translation that can be rescued by exogenous expression of NSun3. We show that NSun3 is required for deposition of m(5)C at the anticodon loop in the mitochondrially encoded transfer RNA methionine (mt-tRNA(Met)). Further, we demonstrate that m(5)C deficiency in mt-tRNA(Met) results in the lack of 5-formylcytosine (f(5)C) at the same tRNA position. Our findings demonstrate that NSUN3 is necessary for efficient mitochondrial translation and reveal that f(5)C in human mitochondrial RNA is generated by oxidative processing of m(5)C.This work was funded by the Medical Research Council (MRC; as part of the core funding for the Mitochondrial Biology Unit MC_U105697135 and by the G0801904 grant), the European Research Council (ERC; 310360), Cancer Research UK (CR-UK; C10701/ A15181), European Commission (FP7/2007-2013, under grant agreement number no.262055 (ESGI), as a Transnational Access project of the European Sequencing and Genotyping Infrastructure), core support grant from the Wellcome Trust and MRC to the Wellcome Trust-MRC Cambridge Stem Cell Institute, the European Commission (Horizon2020, under grant agreement number 633974), the Bundesministerium fur Bildung und Forschung (BMBF) (through the German Network for mitochondrial disorders (mitoNET, 01GM1113C) and through the European network for mitochondrial disorders (E-Rare project GENOMIT, 01GM1207)) and by EMBO (ALFT 701-2013).This is the final version of the article. It first appeared from Nature Publishing Group via http://dx.doi.org/10.1038/ncomms1203
Assessing the cost of global biodiversity and conservation knowledge
Knowledge products comprise assessments of authoritative information supported by stan-dards, governance, quality control, data, tools, and capacity building mechanisms. Considerable resources are dedicated to developing and maintaining knowledge productsfor biodiversity conservation, and they are widely used to inform policy and advise decisionmakers and practitioners. However, the financial cost of delivering this information is largelyundocumented. We evaluated the costs and funding sources for developing and maintain-ing four global biodiversity and conservation knowledge products: The IUCN Red List ofThreatened Species, the IUCN Red List of Ecosystems, Protected Planet, and the WorldDatabase of Key Biodiversity Areas. These are secondary data sets, built on primary datacollected by extensive networks of expert contributors worldwide. We estimate that US116–204 million), plus 293 person-years of volunteer time (range: 278–308 person-years) valued at US12–16 million), were invested inthese four knowledge products between 1979 and 2013. More than half of this financingwas provided through philanthropy, and nearly three-quarters was spent on personnelcosts. The estimated annual cost of maintaining data and platforms for three of these knowl-edge products (excluding the IUCN Red List of Ecosystems for which annual costs were notpossible to estimate for 2013) is US6.2–6.7 million). We esti-mated that an additional US12 million. These costs are much lower than those tomaintain many other, similarly important, global knowledge products. Ensuring that biodi-versity and conservation knowledge products are sufficiently up to date, comprehensiveand accurate is fundamental to inform decision-making for biodiversity conservation andsustainable development. Thus, the development and implementation of plans for sustain-able long-term financing for them is critical
The IRAC point response function in the warm Spitzer mission
The Infrared Array Camera (IRAC) is now the only science instrument in operation on the Spitzer Space Telescope. The 3.6 and 4.5 µm channels are temperature-stabilized at ~28.7K, and the sensitivity of IRAC is nearly identical to what it was in the cryogenic mission. The instrument point response function (PRF) is a set of values from which one can determine the point spread function (PSF) for a source at any position in the field, and is dependent on the optical characteristics of the telescope and instrument as well as the detector sampling and pixel response. These data are necessary when performing PSF-fitting photometry of sources, for deconvolving an IRAC image, subtracting out a bright source in a field, or for estimating the flux of a source that saturates the detector. Since the telescope and instrument are operating at a higher temperature in the post-cryogenic mission, we re-derive the PRFs for IRAC from measurements obtained after the warm mission temperature set point and detector biases were finalized and compare them to the 3.6 and 4.5 µm PRFs determined during the cryogenic mission to assess any changes
CHIASM-Net: Artificial Intelligence-Based Direct Identification of Chiasmal Abnormalities in Albinism
Purpose: Albinism is a congenital disorder affecting pigmentation levels, structure, and function of the visual system. The identification of anatomical changes typical for people with albinism (PWA), such as optic chiasm malformations, could become an important component of diagnostics. Here, we tested an application of convolutional neural networks (CNNs) for this purpose.Methods: We established and evaluated a CNN, referred to as CHIASM-Net, for the detection of chiasmal malformations from anatomic magnetic resonance (MR) images of the brain. CHIASM-Net, composed of encoding and classification modules, was developed using MR images of controls (n = 1708) and PWA (n = 32). Evaluation involved 8-fold cross validation involving accuracy, precision, recall, and F1-score metrics and was performed on a subset of controls and PWA samples excluded from the training. In addition to quantitative metrics, we used Explainable AI (XAI) methods that granted insights into factors driving the predictions of CHIASM-Net.Results: The results for the scenario indicated an accuracy of 85 ± 14%, precision of 90 ± 14% and recall of 81 ± 18%. XAI methods revealed that the predictions of CHIASM-Net are driven by optic-chiasm white matter and by the optic tracts.Conclusions: CHIASM-Net was demonstrated to use relevant regions of the optic chiasm for albinism detection from magnetic resonance imaging (MRI) brain anatomies. This indicates the strong potential of CNN-based approaches for visual pathway analysis and ultimately diagnostics
Visualizing alpha-synuclein and iron deposition in M83 mouse model of Parkinson's disease in vivo
BACKGROUND
Abnormal alpha-synuclein and iron accumulation in the brain play an important role in Parkinson's disease (PD). Herein, we aim at visualizing alpha-synuclein inclusions and iron deposition in the brains of M83 (A53T) mouse models of PD in vivo .
METHODS
Fluorescently labelled pyrimidoindole-derivative THK-565 was characterized by using recombinant fibrils and brains from 10-11 months old M83 mice, which subsequently underwent in vivo concurrent wide-field fluorescence and volumetric multispectral optoacoustic tomography (vMSOT) imaging. The in vivo results were verified against structural and susceptibility weighted imaging (SWI) magnetic resonance imaging (MRI) at 9.4 Tesla and scanning transmission X-ray microscopy (STXM) of perfused brains. Brain slice immunofluorescence and Prussian blue staining were further performed to validate the detection of alpha-synuclein inclusions and iron deposition in the brain, respectively.
RESULTS
THK-565 showed increased fluorescence upon binding to recombinant alpha-synuclein fibrils and alpha-synuclein inclusions in post-mortem brain slices from patients with Parkinson's disease and M83 mice. i.v. administration of THK-565 in M83 mice showed higher cerebral retention at 20 and 40 minutes post-injection by wide-field fluorescence compared to non-transgenic littermate mice, in congruence with the vMSOT findings. SWI/phase images and Prussian blue indicated the accumulation of iron deposits in the brains of M83 mice, presumably in the Fe form, as evinced by the STXM results.
CONCLUSION
We demonstrated in vivo mapping of alpha-synuclein by means of non-invasive epifluorescence and vMSOT imaging assisted with a targeted THK-565 label and SWI/STXM identification of iron deposits in M83 mouse brains ex vivo
Comment on "The extent of forest in dryland biomes"
Bastin et al (Reports, 12 May 2017, p. 635) infer forest as more globally extensive than previously estimated using tree cover data. However, their forest definition does not reflect ecosystem function or biotic composition. These structural and climatic definitions inflate forest estimates across the tropics and undermine conservation goals, leading to inappropriate management policies and practices in tropical grassy ecosystems
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