In most atmospheric circulation models used for climate projections, cloud and convective processes are not explicitly resolved but parameterized. Such models are known to produce a diurnal cycle of ...continental thunderstorms in phase with insolation, while observed precipitation peaks in late afternoon. We propose a new approach which corrects this long standing bias of parameterized convection. In this approach, deep convection triggering and intensity are controlled by sub‐cloud processes: here boundary layer thermals and gust fronts, and potentially orography or surface heterogeneities. The representation of the diurnal cycle of deep convection is greatly improved in 1D mode, with rainfall maximum delayed from midday to late afternoon, provided parameterizations account for the key role played by shallow cumulus in preconditioning deep convection and by gust fronts in the self‐sustaining of thunderstorms in the afternoon.
Thermal barrier coatings (TBC) in service are prone to the attack by molten calcium–magnesium aluminosilicates (CMAS) resulting from the ingestion of siliceous minerals (dust, sand, volcanic ash) by ...the aeroengines. As CMAS deposits observed on ex-service parts present complex and highly variable compositions, progress in the understanding of the interaction mechanism between CMAS and TBC has been mostly obtained during laboratory experiments using simplified CMAS compositions.
This paper consists in a microstructural characterization of the isothermal chemical interaction between a synthetic calcium aluminosilicate (CAS) and a standard 8YPSZ EB-PVD coating deposited on alumina substrates. The chosen CAS is the lowest melting temperature eutectic (1170°C) in the ternary (CaO–Al2O3–SiO2) system and it is prepared as a glass. The evolution of the reaction zone morphology and chemistry is studied after 1200°C treatments from 15min to 100h. The CAS/TBC interaction is governed by the classical mechanism of dissolution/reprecipitation with formation of Y-lean zirconia and Ca2Zr(Y)Si4O12. Ca2Zr(Y)Si4O12 formation induces local variation in the CAS composition leading to CaAl2Si2O8 (anorthite) precipitation. Y2O3 depletion in the YSZ regions infiltrated by CAS is attested using X-ray compositional mapping and the association of EDS and EBSD clearly illustrates that the morphological transformation from porous initial YSZ to dense globular Y-lean YSZ is associated with the structural transformation from initial tetragonal t′ to tetragonal Y-lean zirconia transforming into monoclinic during cooling.
The degradation of the TBC columns increases with the duration of the 1200°C heat-treatment. The interfacial Ca2Zr(Y)Si4O12 phase forms on an increasing amount of columns and is finally observed on all the columns. Interfacial phase formation is discussed and compared to other phase assemblages reported in the literature.
•CAS/8YPSZ interaction is characterized after 1200°C treatments from 15min to 100h.•CAS is the lowest melting eutectic (1170°C) in the ternary (CaO–Al2O3–SiO2) system.•CAS/8YPSZ interaction obeys the classical mechanism of dissolution/reprecipitation.•Interfacial Y-lean zirconia as well as Ca2Zr(Y)Si4O12 and CaAl2Si2O8 are observed.•The degradation of the TBC columns increases with the 1200°C treatment duration.
Reverse genetics techniques are powerful tools for studying gene functions. In the model diatom Phaeodactylum tricornutum, RNAi-mediated knockdown of genes still is the most commonly used reverse ...genetics technique. Due to the diploidic life cycle missing reproduction in lab cultures, many commonly used techniques to create knockout instead of knockdown lines are not applicable in P. tricornutum. These limitations can be overcome by using genome editing approaches like TALEN (Transcription activator-like effector nucleases), and/or CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats), allowing the introduction of targeted mutagenesis events. Both techniques have recently been adapted exemplarily for diatoms, however, no concise guidelines exist yet for routine utilization of these tools and the subsequent characterization of the mutants. We therefore have adapted a cost-effective TALEN generation system previously established for mammalian cells for the use in P. tricornutum, allowing the assembly of TALENs in about two weeks. We further provide protocols for: a) choosing a TALEN target site in order to avoid potentially ineffective and/or off-target prone TALEN constructs, b) efficient transformation of P. tricornutum with both TALEN constructs, utilizing two antibiotics resistance markers, c) effective screening of the transformants. In order to test our system we chose the blue-light dependent transcription factor Aureochrome 1a (PtAureo1a) as a target gene due to the known phenotype of previously characterized P. tricornutum RNAi knockdown strains. Our TALEN approach appears to be highly efficient: targeted mutation events were detected in 50% of all transformants obtained, whereas 21% of the transformants were found to be bi-allelic knockout lines. Furthermore, most TALEN transformed cell lines were found to be genetically homogeneous without the need for re-plating, which greatly facilitates the screening process.
•TALEN is an effective tool for genome-editing in the diatom P. tricornutum.•Guidelines for target site design and the screening process have been established.•21% of the obtained transformants were found to be bi-allelic knockout lines.•Transformants were found to be genetically homogenous.
Diferuloylputrescine has been found in a variety of plant species, and recent work has provided evidence of its covalent bonding into lignin. Results from nuclear magnetic resonance spectroscopy ...revealed the presence of bonding patterns consistent with homo-coupling of diferuloylputrescine and the possibility of cross-coupling with lignin. In the present work, density functional theory calculations have been applied to assess the energetics associated with radical coupling, rearomatization, and dehydrogenation for possible homo-coupled dimers of diferuloylputrescine and cross-coupled dimers of diferuloylputrescine and coniferyl alcohol. The values obtained for these reaction energetics are consistent with those reported for monolignols and other novel lignin monomers. As such, this study shows that there would be no thermodynamic impediment to the incorporation of diferuloylputrescine into the lignin polymer and its addition to the growing list of non-canonical lignin monomers.
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•Diferuloylputrescine has been found in lignin isolated from corn grain fibers.•There is evidence that diferuloylputrescine may homo-couple and/or cross-couple with lignin.•Density functional theory calculations demonstrate the thermodynamic feasibility of such coupling reactions.
This work investigates Secondary Organic Aerosol (SOA) formed by limonene ozonolysis using a housecleaning product in indoor environment. This study combines simulation chamber ozonolysis experiments ...and field studies in an experimental house allowing different scenarios of housecleaning product use in real conditions.
Chemical speciation has been performed using a new method based on simultaneous sampling of both gas and particulate phases on sorbent tubes and filters. This method allowed the identification and quantification of about 35 products in the gas and particulate phases. Among them, products known to be specific from limonene ozonolysis such as limononaldehyde, ketolimonene and ketolimonic acid have been detected. Some other compounds such as 2-methylbutanoic acid had never been detected in previous limonene ozonolysis studies. Some compounds like levulinic acid had already been detected but their formation remained unexplained. Potential reaction pathways are proposed in this study for these compounds. For each experiment, chemical data are coupled together with physical characterization of formed particles: mass and size and number distribution evolution which allowed the observation of new particles formation (about 87,000 particle cm−3). The chemical speciation associated to aerosol size distribution results confirmed that limonene emitted by the housecleaning product was responsible for SOA formation. To our knowledge, this work provides the most comprehensive analytical study of detected compounds in a single experiment for limonene ozonolysis in both gaseous and particulate phases in real indoor environment.
•Observation of Secondary Organic Aerosols formation from limonene ozonolysis.•Identification of about 35 oxygenated products in the gaseous and particulate phases.•Detection of specific products from limonene ozonolysis reaction.•Proposition of reaction pathways for new detected products from limonene ozonolysis.
Brewer's spent grain (BSG) is an important by-product from the brewing process produced in high amounts worldwide. BSG is rich in carbohydrates, lignin, proteins and lipids. In this work, the ...chemical composition of the lipids in BSG was studied in detail by gas chromatography and mass spectrometry. The predominant lipids were triglycerides (67% of total extract), followed by a series of free fatty acids (18%). Lower amounts of monoglycerides (1.6%) and diglycerides (7.7%) were also identified among the lipids in BSG, together with minor amounts of other aliphatic series such as n-alkanes and alkylresorcinols. Steroid compounds (steroid hydrocarbons, steroid ketones, free sterols, sterol esters and sterol glycosides) were also found in important amounts in BSG (ca. 5%), with free and conjugated sterols being the most abundant steroids. BSG can thus be regarded as a valuable source of phytochemicals of interest for the pharmaceutical, cosmetic, food or other industries.
•The chemical composition of the lipids in brewer's spent grain was studied in detail.•Fatty acids, triglycerides and phytosterols are the predominant compounds.•BSG is a promising source of highly valuable phytochemicals of industrial interest.
Aims
Insulin‐like growth factor 1 (IGF‐1)‐dependent signalling promotes exercise‐induced physiological cardiac hypertrophy. However, the in vivo therapeutic potential of IGF‐1 for heart disease is ...not well established. Here, we test the potential therapeutic benefits of IGF‐1 on cardiac function using an in vivo model of chronic catecholamine‐induced cardiomyopathy.
Methods
Rats were perfused with isoproterenol via osmotic pump (1 mg kg−1 per day) and treated with 2 mg kg−1 IGF‐1 (2 mg kg−1 per day, 6 days a week) for 2 or 4 weeks. Echocardiography, ECG, and blood pressure were assessed. In vivo pressure–volume loop studies were conducted at 4 weeks. Heart sections were analysed for fibrosis and apoptosis, and relevant biochemical signalling cascades were assessed.
Results
After 4 weeks, diastolic function (EDPVR, EDP, tau, E/A ratio), systolic function (PRSW, ESPVR, dP/dtmax) and structural remodelling (LV chamber diameter, wall thickness) were all adversely affected in isoproterenol‐treated rats. All these detrimental effects were attenuated in rats treated with Iso+IGF‐1. Isoproterenol‐dependent effects on BP were attenuated by IGF‐1 treatment. Adrenergic sensitivity was blunted in isoproterenol‐treated rats but was preserved by IGF‐1 treatment. Immunoblots indicate that cardioprotective p110α signalling and activated Akt are selectively upregulated in Iso+IGF‐1‐treated hearts. Expression of iNOS was significantly increased in both the Iso and Iso+IGF‐1 groups; however, tetrahydrobiopterin (BH4) levels were decreased in the Iso group and maintained by IGF‐1 treatment.
Conclusion
IGF‐1 treatment attenuates diastolic and systolic dysfunction associated with chronic catecholamine‐induced cardiomyopathy while preserving adrenergic sensitivity and promoting BH4 production. These data support the potential use of IGF‐1 therapy for clinical applications for cardiomyopathies.
The structure of the lignin in wheat straw has been investigated by a combination of analytical pyrolysis, 2D-NMR, and derivatization followed by reductive cleavage (DFRC). It is a ...p-hydroxyphenyl-guaiacyl-syringyl lignin (with an H:G:S ratio of 6:64:30) associated with p-coumarates and ferulates. 2D-NMR indicated that the main substructures present are β-O-4′-ethers (∼75%), followed by phenylcoumarans (∼11%), with lower amounts of other typical units. A major new finding is that the flavone tricin is apparently incorporated into the lignins. NMR and DFRC indicated that the lignin is partially acylated (∼10%) at the γ-carbon, predominantly with acetates that preferentially acylate guaiacyl (12%) rather than syringyl (1%) units; in dicots, acetylation is predominantly on syringyl units. p-Coumarate esters were barely detectable (<1%) on monomer conjugates released by selectively cleaving β-ethers in DFRC, indicating that they might be preferentially involved in condensed or terminal structures.
Since the discovery of the secondary preventive benefits of antiretroviral therapy, national and international governing bodies have called for countries to reach 90% diagnosis, ART engagement and ...viral suppression among people living with HIV/AIDS. The US HIV epidemic is dispersed primarily across large urban centers, each with different underlying epidemiological and structural features. We selected six US cities, including Atlanta, Baltimore, Los Angeles, Miami, New York, and Seattle, with the objective of demonstrating the breadth of epidemiological and structural differences affecting the HIV/AIDS response across the US. We synthesized current and publicly-available surveillance, legal statutes, entitlement and discretionary funding, and service location data for each city. The vast differences we observed in each domain reinforce disparities in access to HIV treatment and prevention, and necessitate targeted, localized strategies to optimize the limited resources available for each city’s HIV/AIDS response.
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