We hypothesized that rates of myofibrillar and patellar tendon collagen synthesis would fall over time during disuse, the
changes being accompanied in muscle by decreases in focal adhesion kinase ...(FAK) phosphorylation and in gene expression for
proteolytic enzymes. We studied nine men (22 ± 4 years, BMI 24 ± 3 kg m â2 (means ± s.d. ) who underwent unilateral lower leg suspension for 23 days; five were studied between 0 and 10 days and four between 10 and
21 days. Muscle and tendon biopsies were taken in the postabsorptive state at days 0, 10 and 21 for measurement of protein
synthesis, gene expression and protein phosphorylation. Muscle cross-sectional area decreased by 5.2% at 14 days and 10.0%
(both P < 0.001), at 23 days, i.e. 0.5% day â1 , whereas tendon dimensions were constant. Rates of myofibrillar protein synthesis fell ( P < 0.01) from 0.047% h â1 at day 0 to 0.022% h â1 at 10 days without further changes. Tendon collagen synthetic rates also fell ( P < 0.01), from 0.052 to 0.023% h â1 at 10 days and then to 0.010% h â1 at 21 days. FAK phosphorylation decreased 30% ( P < 0.01) at 10 days. No changes occurred in the amounts/phosphorylation of PKBâP70s6kâmTOR pathway components. Expression
of mRNA for MuRF-1 increased â¼3-fold at 10 days without changes in MAFbx or tripeptidyl peptidase II mRNA, but all decreased
between 10 and 21 days. Thus, both myofibrillar and tendon protein synthetic rates show progressive decreases during 21 days
of disuse; in muscle, this is accompanied by decreased phosphorylation of FAK, with no marked increases in genes for proteolytic
enzymes.
DNA replication is essential to all living organisms as it ensures the fidelity of genetic material for the next generation of dividing cells. One of the simplest replication initiation mechanisms is ...the rolling circle replication. In the streptococcal plasmid pMV158, which confers antibiotic resistance to tetracycline, replication initiation is catalysed by RepB protein. The RepB N-terminal domain or origin binding domain binds to the recognition sequence (bind locus) of the double-strand origin of replication and cleaves one DNA strand at a specific site within the nic locus. Using biochemical and crystallographic analyses, here we show how the origin binding domain recognises and binds to the bind locus using structural elements removed from the active site, namely the recognition α helix, and a β-strand that organises upon binding. A new hexameric structure of full-length RepB that highlights the great flexibility of this protein is presented, which could account for its ability to perform different tasks, namely bind to two distinct loci and cleave one strand of DNA at the plasmid origin.
In contrast to many countries, a decrease in childhood wheeze prevalence was previously reported for the Netherlands. In repeated cross‐sectional surveys in 2001, 2005 and 2010, we investigated ...whether this trend continued, and additionally examined prevalence trends of eczema, asthma and rhinoconjunctivitis among 8‐ to 11‐year‐old schoolchildren eligible for a routine physical examination. Overall, ~90% participated (mean age: 8.8 years in 2001 and 10.5 years in 2005 and 2010). Eczema, wheeze and asthma prevalence did not change significantly between 2001 and 2010, but rhinoconjunctivitis prevalence increased from 8.4% in 2001 to 12.3% in both 2005 and 2010 (Ptrend < 0.01). In conclusion, after a decrease in wheeze prevalence among Dutch schoolchildren between 1989 and 2001, no further decrease was observed until 2010. Similarly, the prevalence of eczema and asthma remained stable, but rhinoconjunctivitis prevalence increased between 2001 and 2010. The latter may be an effect of older age and not a true increase over time.
Bringing all the pieces together: By arranging the blunt‐end duplex DNA strands of “continuous” three‐way junctions around themselves through noncovalent interactions and inducing the formation of ...local “discontinuous” three‐way junctions, supramolecular cylinders promote the self‐assembly of 3D DNA networks with tunable physical and chemical properties (see the arrangement of the junctions in the portion of the lattice structure shown).
A plants' fitness to a large extent depends on its capacity to adapt to spatio-temporally varying environmental conditions. One such environmental condition to which plants display extensive ...phenotypic plasticity is soil nitrate levels and patterns. In response to heterogeneous nitrate distribution, plants show a so-called preferential foraging response. Herein root growth is enhanced in high nitrate patches and repressed in low nitrate locations beyond a level that can be explained from local nitrate sensing. Although various molecular players involved in this preferential foraging behavior have been identified, how these together shape root system adaptation has remained unresolved. Here we use a simple modeling approach in which we incrementally incorporate the known molecular pathways to investigate the combination of regulatory mechanisms that underly preferential root nitrate foraging. Our model suggests that instead of involving a growth suppressing supply signal, growth reduction on the low nitrate side may arise from reduced root foraging and increased competition for carbon. Additionally, our work suggests that the long distance CK signaling involved in preferential root foraging may function as a supply signal modulating demand signaling strength. We illustrate how this integration of demand and supply signals prevents excessive preferential foraging under conditions in which demand is not met by sufficient supply and a more generic foraging in search of nitrate should be maintained.
The Elastic Properties of Clay in Shales Sayers, Colin M.; Boer, Lennert D.
Journal of geophysical research. Solid earth,
July 2018, 2018-07-00, 20180701, Volume:
123, Issue:
7
Journal Article
Peer reviewed
The mechanical properties of clay minerals are important in many diverse scientific disciplines, including soil mechanics, civil engineering, materials science, and petroleum exploration. Rock ...physics provides a link between the elastic properties of rocks and their constitutive properties such as mineralogic composition, porosity, and pore‐fluid content. To accurately characterize shales, rock physics models must account for the anisotropic properties of clay minerals. Due to more compliant regions between clay particles, the elastic stiffness of clay in shales is significantly less than that of its constituent clay minerals. In this paper, the clay in shales is modeled as anisotropic clay platelets surrounded by a softer interparticle region consisting of clay‐bound water and interparticle contacts. Inverting for the elastic properties of this interparticle region indicates that its effective bulk modulus is like that of water. However, it has a nonzero effective shear modulus that is smaller by an order of magnitude, consistent with the expected shear modulus of clay‐bound water. Owing to its simplicity and robustness, it is anticipated that this model of shales, based on the properties of clay minerals and the interparticle medium, will find use in many rock physics applications, including seismic imaging, seismic inversion, and geomechanics.
Key Points
To accurately characterize shales, rock physics models must account for anisotropic clay minerals
Due to compliant regions between clay platelets, the elastic stiffness of clay in shales is much less than that of clay minerals
The clay in shales can be modeled as anisotropic clay platelets embedded in a softer interparticle region containing clay‐bound water
The Boolardy Engineering Test Array is a 6 × 12 m dish interferometer and the prototype of the Australian Square Kilometre Array Pathfinder (ASKAP), equipped with the first generation of ASKAP's ...phased array feed (PAF) receivers. These facilitate rapid wide-area imaging via the deployment of simultaneous multiple beams within an ∼30 deg2 field of view. By cycling the array through 12 interleaved pointing positions and using nine digitally formed beams, we effectively mimic a traditional 1 h × 108 pointing survey, covering ∼150 deg2 over 711–1015 MHz in 12 h of observing time. Three such observations were executed over the course of a week. We verify the full bandwidth continuum imaging performance and stability of the system via self-consistency checks and comparisons to existing radio data. The combined three epoch image has arcminute resolution and a 1σ thermal noise level of 375 μJy beam−1, although the effective noise is a factor of ∼3 higher due to residual sidelobe confusion. From this we derive a catalogue of 3722 discrete radio components, using the 35 per cent fractional bandwidth to measure in-band spectral indices for 1037 of them. A search for transient events reveals one significantly variable source within the survey area. The survey covers approximately two-thirds of the Spitzer South Pole Telescope Deep Field. This pilot project demonstrates the viability and potential of using PAFs to rapidly and accurately survey the sky at radio wavelengths.
Summary
Background
An altered immune response against Staphylococcus aureus might contribute to inflammation and barrier damage in atopic dermatitis (AD).
Objectives
To profile IgG antibodies against ...55 S. aureus antigens in sera of children with mild‐to‐severe AD and to evaluate the association between IgG levels and disease severity.
Methods
In this cross‐sectional study, we included children with AD from two interventional study cohorts, the Shared Medical Appointment (SMA) cohort (n = 131) and the older DAVOS cohort (n = 76). AD severity was assessed using the Self‐Administered Eczema Area and Severity Index (SA‐EASI) and levels of thymus and activation‐regulated chemokine (TARC) in serum. IgG antibody levels against 55 S. aureus antigens were quantified simultaneously using a Luminex assay. Pair‐wise correlations were calculated between the 55 IgG levels using the Spearman rank correlation test. Linear regression analysis was performed to test for associations between 55 IgG levels and SA‐EASI and TARC, adjusting for age, sex and S. aureus colonization.
Results
In the SMA cohort, 16 antigens were associated with SA‐EASI and 12 with TARC (10 overlapping antigens; P‐values 0·001–0·044). The associated IgG antibodies targeted mainly secreted proteins with immunomodulatory functions. In the DAVOS study, IgG levels against only four and one S. aureus antigen(s) were associated with SA‐EASI and TARC, respectively (no overlap).
Conclusions
In young children, severity of AD is associated with an IgG response directed against S. aureus antigens with mainly immunomodulatory functions. These findings encourage further evaluation of the role of S. aureus in the pathogenesis of AD.
What's already known about this topic?
Staphylococcus aureus plays a major role in the pathogenesis of atopic dermatitis (AD), possibly through the deregulation of immunological pathways.
S. aureus expresses different antigens that could trigger immune responses in AD and contribute to the inflammatory response.
What does this study add?
IgG responses against a large panel of 55 S. aureus antigens were profiled simultaneously.
In young children, AD disease severity was found to be associated with IgG responses directed against antigens with mainly immunomodulatory functions.
What is the translational message?
Studying the interactions between S. aureus and the host IgG immune response in AD helps determine the role and mechanisms of S. aureus in AD inflammation, which might have implications for clinical treatment recommendations.
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This work examines the economic and environmental performance of seawater desalination plants that integrate reverse osmosis, Rankine cycles and solar collectors. The design of these facilities is ...formulated as a multi-objective mixed-integer nonlinear programming model (MINLP) that considers the simultaneous minimization of cost and environmental impact given a certain water demand to be fulfilled. The environmental performance is quantified in terms of contribution to global warming, which is holistically determined following life cycle assessment (LCA) principles. A case study that considers weather data of Tarragona (Spain) is used as benchmark to illustrate the capabilities of the approach presented. Using our rigorous modeling and optimization approach, we show that coupling seawater desalination with solar collectors can lead to significant environmental savings at a small increment in cost. Our systematic tool is aimed at guiding decision-makers towards the adoption of more sustainable technological alternatives for seawater desalination.
► A solar assisted Rankine cycle coupled with a reverse osmosis desalination unit is considered. ► Simultaneous minimization of total cost and environmental impact is implemented. ► Pareto front of optimal solutions is obtained and different designs of the systems are compared. ► Coupling of solar collectors with reverse osmosis is shown to be economically viable. ► The CO
2 emissions can be cut down by 2.1
million
ton for over 20
years.
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