2,822 research outputs found

    Corn Silage Yield and Quality, and Soil Health Metrics After Fall Cover Crop Grazing

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    Integrated crop-livestock systems can potentially produce more product per unit of land with minimal impacts on soil health and cash crop quality. In the Upper Midwest there is an opportunity to graze fall cover crops (CC) after winter wheat in a corn-wheat rotation. In East Lansing, Michigan, two CC treatments: 1) a pure brassica mixture (PURE), and 2) a complex mixture containing legumes, warm and cool season grasses, and brassicas (MIX) were planted after wheat, and grazed by lambs in the fall seasons of 2019 to 2021. The following year, soil health, corn yield and quality were measured from plots corresponding to a non-grazed control and plots grazed in October, November, and December. There was no significant effect on spring soil bulk density and penetration resistance (PR) regardless of CC mixture or the timing of grazing, although PR was numerically higher in the grazed plots. Corn crude protein, acid detergent fiber, and neutral detergent fiber were not different across graze date or CC treatments (P \u3e 0.05), although corn contained more starch when grown after MIX grazed in November (P=0.02). The difference in starch was possibly an artifact of spatial variability across the site. Corn dry matter yield was lower in the non-grazed control (15.35 Mg ha-1) when compared to the grazing treatments in October (17.37 Mg ha-1) and December (17.19 Mg ha-1) (P=0.03). Grazing cover crops in the fall may improve corn yield the following year without causing soil compaction or changing corn quality

    A review of fMRI simulation studies

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    Simulation studies that validate statistical techniques for fMRI data are challenging due to the complexity of the data. Therefore, it is not surprising that no common data generating process is available (i.e. several models can be found to model BOLD activation and noise). Based on a literature search, a database of simulation studies was compiled. The information in this database was analysed and critically evaluated focusing on the parameters in the simulation design, the adopted model to generate fMRI data, and on how the simulation studies are reported. Our literature analysis demonstrates that many fMRI simulation studies do not report a thorough experimental design and almost consistently ignore crucial knowledge on how fMRI data are acquired. Advice is provided on how the quality of fMRI simulation studies can be improved

    A coumaroyl-ester-3-hydroxylase insertion mutant reveals the existence of nonredundant meta-hydroxylation pathways and essential roles for phenolic precursors in cell expansion and plant growth

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    Cytochromes P450 monooxygenases from the CYP98 family catalyze the meta-hydroxylation step in the phenylpropanoid biosynthetic pathway. The ref8 Arabidopsis (Arabidopsis thaliana) mutant, with a point mutation in the CYP98A3 gene, was previously described to show developmental defects, changes in lignin composition, and lack of soluble sinapoyl esters. We isolated a T-DNA insertion mutant in CYP98A3 and show that this mutation leads to a more drastic inhibition of plant development and inhibition of cell growth. Similar to the ref8 mutant, the insertion mutant has reduced lignin content, with stem lignin essentially made of p-hydroxyphenyl units and trace amounts of guaiacyl and syringyl units. However, its roots display an ectopic lignification and a substantial proportion of guaiacyl and syringyl units, suggesting the occurrence of an alternative CYP98A3-independent meta-hydroxylation mechanism active mainly in the roots. Relative to the control, mutant plantlets produce very low amounts of sinapoyl esters, but accumulate flavonol glycosides. Reduced cell growth seems correlated with alterations in the abundance of cell wall polysaccharides, in particular decrease in crystalline cellulose, and profound modifications in gene expression and homeostasis reminiscent of a stress response. CYP98A3 thus constitutes a critical bottleneck in the phenylpropanoid pathway and in the synthesis of compounds controlling plant development. CYP98A3 cosuppressed lines show a gradation of developmental defects and changes in lignin content (40% reduction) and structure (prominent frequency of p-hydroxyphenyl units), but content in foliar sinapoyl esters is similar to the control. The purple coloration of their leaves is correlated to the accumulation of sinapoylated anthocyanins

    Sunitinib induced pyoderma gangrenosum-like ulcerations

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    Pyoderma gangrenosum is a non-infectious neutrophilic skin disease commonly associated with underlying systemic diseases. Histopathological and laboratory diagnostics are unspecific in the majority of the cases and the diagnosis is made in accordance with the clinical picture. Here, we report the case of a 69-year old man with progredient pyoderma gangrenosum-like ulcerations under treatment with sunitinib due to hepatocellular carcinoma. A conventional ulcer therapy did not lead to a regression of the lesions. Solely cessation of sunitinib therapy resulted in an improvement of the ulcerations. Sunitinib is a multikinase inhibitor that targets the PDGF-α - and -β-, VEGF-1-3-, KIT-, FLT3-, CSF-1- and RET-receptor, thereby impairing tumour proliferation, pathological angiogenesis and metastasation. Here, we demonstrate that pyoderma gangrenosum-like ulcers may represent a serious side effect of sunitinib-based anti-cancer treatment

    The calcium isotopic composition of carbonate hardground cements: A new record of changes in ocean chemistry?

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    Reconstructing changes in the calcium isotopic composition (δ44Ca) of the ocean over Earth history has been challenging. This difficulty is due to the large range of calcium isotope fractionation factors during mineral precipitation and the potential for overwriting the initial δ44Ca of minerals during shallow marine diagenesis. We present a new δ44Ca record measured in carbonate hardground cements, an inorganic carbonate-mineral precipitate that rapidly forms at or near the sediment-water interface. The range in the δ44Ca for any particular carbonate hardground cements is between 0.05 and 0.56‰. In some cases, the progressive increase in the δ44Ca during precipitation can be observed, consistent with precipitation in a ‘closed-system’. Our data show an average calcium isotope fractionation during carbonate hardground cement precipitation that is −0.57 ± 0.27‰, similar to the calcium isotope fractionation factor for inorganic calcite precipitates in previous laboratory and modelling studies, and closer to what is considered a kinetic end member calcium isotope fractionation than growth at equilibrium. This is consistent with the rapid carbonate mineral precipitation expected for carbonate hardground cements. Our δ44Ca record over the Phanerozoic is similar to other calcium-bearing mineral records over the same time interval, with average δ44Ca becoming lower going back in time by about 0.5 to 0.7‰. Our results add further support for the evolution of seawater δ44Ca over time, and we discuss the possible causes of these changes with suggestions for future studies

    Single-Pion Production in pp Collisions at 0.95 GeV/c (II)

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    The single-pion production reactions pp→dπ+pp\to d\pi^+, pp→npπ+pp\to np\pi^+ and pp→ppπ0pp\to pp\pi^0 were measured at a beam momentum of 0.95 GeV/c (Tp≈T_p \approx 400 MeV) using the short version of the COSY-TOF spectrometer. The central calorimeter provided particle identification, energy determination and neutron detection in addition to time-of-flight and angle measurements from other detector parts. Thus all pion production channels were recorded with 1-4 overconstraints. Main emphasis is put on the presentation and discussion of the npπ+np\pi^+ channel, since the results on the other channels have already been published previously. The total and differential cross sections obtained are compared to theoretical calculations. In contrast to the ppπ0pp\pi^0 channel we find in the npπ+np\pi^+ channel a strong influence of the Δ\Delta excitation already at this energy close to threshold. In particular we find a (3cos2Θ+1)(3 cos^2\Theta + 1) dependence in the pion angular distribution, typical for a pure s-channel Δ\Delta excitation and identical to that observed in the dπ+d\pi^+ channel. Since the latter is understood by a s-channel resonance in the 1D2^1D_2 pnpn partial wave, we discuss an analogous scenario for the pnπ+pn\pi^+ channel

    Engineering the Controlled Assembly of Filamentous Injectisomes in E. coli K-12 for Protein Translocation into Mammalian Cells.

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    Bacterial pathogens containing type III protein secretion systems (T3SS) assemble large needle-like protein complexes in the bacterial envelope, called injectisomes, for translocation of protein effectors into host cells. The application of these molecular syringes for the injection of proteins into mammalian cells is hindered by their structural and genomic complexity, requiring multiple polypeptides encoded along with effectors in various transcriptional units (TUs) with intricate regulation. In this work, we have rationally designed the controlled expression of the filamentous injectisomes found in enteropathogenic Escherichia coli (EPEC) in the nonpathogenic strain E. coli K-12. All structural components of EPEC injectisomes, encoded in a genomic island called the locus of enterocyte effacement (LEE), were engineered in five TUs (eLEEs) excluding effectors, promoters and transcriptional regulators. These eLEEs were placed under the control of the IPTG-inducible promoter Ptac and integrated into specific chromosomal sites of E. coli K-12 using a marker-less strategy. The resulting strain, named synthetic injector E. coli (SIEC), assembles filamentous injectisomes similar to those in EPEC. SIEC injectisomes form pores in the host plasma membrane and are able to translocate T3-substrate proteins (e.g., translocated intimin receptor, Tir) into the cytoplasm of HeLa cells reproducing the phenotypes of intimate attachment and polymerization of actin-pedestals elicited by EPEC bacteria. Hence, SIEC strain allows the controlled expression of functional filamentous injectisomes for efficient translocation of proteins with T3S-signals into mammalian cells

    Photoluminescence investigations of 2D hole Landau levels in p-type single Al_{x}Ga_{1-x}As/GaAs heterostructures

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    We study the energy structure of two-dimensional holes in p-type single Al_{1-x}Ga_{x}As/GaAs heterojunctions under a perpendicular magnetic field. Photoluminescence measurments with low densities of excitation power reveal rich spectra containing both free and bound-carrier transitions. The experimental results are compared with energies of valence-subband Landau levels calculated using a new numerical procedure and a good agreement is achieved. Additional lines observed in the energy range of free-carrier recombinations are attributed to excitonic transitions. We also consider the role of many-body effects in photoluminescence spectra.Comment: 13 pages, 10 figures, accepted to Physical Review

    Esperanto for histones : CENP-A, not CenH3, is the centromeric histone H3 variant

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    The first centromeric protein identified in any species was CENP-A, a divergent member of the histone H3 family that was recognised by autoantibodies from patients with scleroderma-spectrum disease. It has recently been suggested to rename this protein CenH3. Here, we argue that the original name should be maintained both because it is the basis of a long established nomenclature for centromere proteins and because it avoids confusion due to the presence of canonical histone H3 at centromeres
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