Understanding the motion of magnetic skyrmions is essential if they are to be used as information carriers in devices. It is now shown that topological confinement endows the skyrmions with an ...unexpectedly large mass, which plays a key role in their dynamics.
Drosophila suzukii flies cause economic losses to fruit crops globally. Previous work shows various Drosophila species are attracted to volatile metabolites produced by individual fruit associated ...yeast isolates, but fruits naturally harbour a rich diversity of yeast species. Here, we report the relative attractiveness of D. suzukii to yeasts presented individually or in combinations using laboratory preference tests and field trapping data. Laboratory trials revealed four of 12 single yeast isolates were attractive to D. suzukii, of which Metschnikowia pulcherrima and Hanseniaspora uvarum were also attractive in field trials. Four out of 10 yeast combinations involving Candida zemplinina, Pichia pijperi, M. pulcherrima and H. uvarum were attractive in the laboratory. Whilst a combination of M. pulcherrima + H. uvarum trapped the greatest number of D. suzukii in the field, the efficacy of the M. pulcherrima + H. uvarum combination to trap D. suzukii was not significantly greater than traps primed with volatiles from only H. uvarum. While volatiles from isolates of M. pulcherrima and H. uvarum show promise as baits for D. suzukii, further research is needed to ascertain how and why flies are attracted to certain baits to optimise control efficacy.
Ultrashort, coherent x-ray pulses of a free-electron laser are used to holographically image the magnetization dynamics within a magnetic domain pattern after creation of a localized excitation via ...an optical standing wave. We observe a spatially confined reduction of the magnetization within a couple of hundred femtoseconds followed by its slower recovery. Additionally, the experimental results show evidence of a spatial evolution of magnetization, which we attribute to ultrafast transport of nonequilibrium spin-polarized electrons for early times and to a fluence-dependent remagnetization rate for later times.
During ultrafast demagnetization of a magnetically ordered solid, angular momentum has to be transferred between the spins, electrons, and phonons in the system on femto- and picosecond timescales. ...Although the intrinsic spin-transfer mechanisms are intensely debated, additional extrinsic mechanisms arising due to nanoscale heterogeneity have only recently entered the discussion. Here we use femtosecond X-ray pulses from a free-electron laser to study thin film samples with magnetic domain patterns. We observe an infrared-pump-induced change of the spin structure within the domain walls on the sub-picosecond timescale. This domain-topography-dependent contribution connects the intrinsic demagnetization process in each domain with spin-transport processes across the domain walls, demonstrating the importance of spin-dependent electron transport between differently magnetized regions as an ultrafast demagnetization channel. This pathway exists independent from structural inhomogeneities such as chemical interfaces, and gives rise to an ultrafast spatially varying response to optical pump pulses.
Background
Fish oil supplementation has been shown to alter gene expression of mononuclear cells both in vitro and in vivo. However, little is known about the total transcriptome profile in healthy ...subjects after intake of fish oil. We therefore investigated the gene expression profile in peripheral blood mononuclear cells (PBMCs) after intake of fish oil for 7 weeks using transcriptome analyses.
Design
In a 7‐week, double‐blinded, randomized, controlled, parallel‐group study, healthy subjects received 8 g day−1 fish oil (1.6 g day−1 eicosapentaenoic acid + docosahexaenoic acid) (n = 17) or 8 g day−1 high oleic sunflower oil (n = 19). Microarray analyses of RNA isolated from PBMCs were performed at baseline and after 7 weeks of intervention.
Results
Cell cycle, DNA packaging and chromosome organization are biological processes found to be upregulated after intake of fish oil compared to high oleic sunflower oil using a moderated t‐test. In addition, gene set enrichment analysis identified several enriched gene sets after intake of fish oil. The genes contributing to the significantly different gene sets in the subjects given fish oil compared with the control group are involved in cell cycle, endoplasmic reticulum (ER) stress and apoptosis. Gene transcripts with common motifs for 35 known transcription factors including E2F, TP53 and ATF4 were upregulated after intake of fish oil.
Conclusion
We have shown that intake of fish oil for 7 weeks modulates gene expression in PBMCs of healthy subjects. The increased expression of genes related to cell cycle, ER stress and apoptosis suggests that intake of fish oil may modulate basic cellular processes involved in normal cellular function.
The cysteine protease cathepsin B (CTSB) is frequently overexpressed in human breast cancer and correlated with a poor prognosis. Genetic deficiency or pharmacological inhibition of CTSB attenuates ...tumor growth, invasion and metastasis in mouse models of human cancers. CTSB is expressed in both cancer cells and cells of the tumor stroma, in particular in tumor-associated macrophages (TAM). In order to evaluate the impact of tumor- or stromal cell-derived CTSB on Polyoma Middle T (PyMT)-induced breast cancer progression, we used in vivo and in vitro approaches to induce human CTSB overexpression in PyMT cancer cells or stromal cells alone or in combination. Orthotopic transplantation experiments revealed that CTSB overexpression in cancer cells rather than in the stroma affects PyMT tumor progression. In 3D cultures, primary PyMT tumor cells showed higher extracellular matrix proteolysis and enhanced collective cell invasion when CTSB was overexpressed and proteolytically active. Coculture of PyMT cells with bone marrow-derived macrophages induced a TAM-like macrophage phenotype in vitro, and the presence of such M2-polarized macrophages in 3D cultures enhanced sprouting of tumor spheroids. We employed a doxycycline (DOX)-inducible CTSB expression system to selectively overexpress human CTSB either in cancer cells or in macrophages in 3D cocultures. Tumor spheroid invasiveness was only enhanced when CTSB was overexpressed in cancer cells, whereas CTSB expression in macrophages alone did not further promote invasiveness of tumor spheroids. We conclude that CTSB overexpression in the PyMT mouse model promotes tumor progression not by a stromal effect, but by a direct, cancer cell-inherent mode of action: CTSB overexpression renders the PyMT cancers more invasive by increasing proteolytic extracellular matrix protein degradation fostering collective cell invasion into adjacent tissue.
NMR spectroscopy at ultra‐high magnetic fields requires improved radiofrequency (rf) pulses to cover the increased spectral bandwidth. Optimized 90° pulse pairs were introduced as Ramsey‐type ...cooperative (Ram‐COOP) pulses for biomolecular NMR applications. The Ram‐COOP element provides broadband excitation with enhanced sensitivity and reduced artifacts even at magnetic fields >1.0 GHz 1H Larmor frequency (23 T). A pair of 30 μs Ram‐COOP pulses achieves an excitation bandwidth of 100 kHz with a maximum rf field of 20 kHz, more than three‐fold improved compared to excitation by rectangular pulses. Ram‐COOP pulses exhibit little offset‐dependent phase errors and are robust to rf inhomogeneity. The performance of the Ram‐COOP element is experimentally confirmed with heteronuclear multidimensional NMR experiments, applied to proteins and nucleic acids. Ram‐COOP provides broadband excitation at low rf field strength suitable for application at current magnetic fields and beyond 23 T.
Ultra‐highfield NMR magnet development requires robust radio frequency pulses to cover the increasing frequency spectral bandwidth. Cooperative excitation pulses are presented with pulse durations on the order of tens of microseconds, which provide ultrabroadband excitation for present and future magnetic field strengths well beyond 28 T (1.2 GHz 1H). The performance is demonstrated for proteins and nucleic acids.
Sequential femtosecond X-ray imaging Günther, C. M; Eisebitt, S; Zacharias, H ...
Nature photonics,
02/2011, Letnik:
5, Številka:
2
Journal Article
Recenzirano
Recording a 'molecular movie' with atomic spatial resolution on the femtosecond timescale set by atomic motion can be considered the ultimate goal of dynamic real-space imaging. Free-electron X-ray ...lasers, with their (sub)nanometre wavelength, femtosecond pulse duration and high brilliance, fuel the hope that this may ultimately become possible. Single-shot still pictures with sub-100 nm resolution achieved during femtosecond exposures have recently been demonstrated. A femtosecond time-lapse movie requires a sequence of independent images taken with a controllable time delay. As a key step towards achieving a molecular movie, we demonstrate a holographic imaging approach capable of recording two fully independent images with a variable time delay over the entire femtosecond regime. The concept overcomes the fundamental readout time limitations of two-dimensional area detectors, as two subsequent X-ray holograms of a sample can be superimposed within one detector exposure and yet be unambiguously disentangled to reconstruct two independent images.
Microbes play key roles in animal welfare and food safety but there is little understanding of whether microbiomes associated with livestock vary in space and time. Here we analysed the bacteria ...associated with the carcasses of the same breed of 28 poultry broiler flocks at different stages of processing across two climatically similar UK regions over two seasons with 16S metabarcode DNA sequencing. Numbers of taxa types did not differ by region, but did by season (P = 1.2 × 10−19), and numbers increased with factory processing, especially in summer. There was also a significant (P < 1 × 10−4) difference in the presences and abundances of taxa types by season, region and factory processing stage, and the signal for seasonal and regional differences remained highly significant on final retail products. This study therefore revealed that both season and region influence the types and abundances of taxa on retail poultry products. That poultry microbiomes differ in space and time should be considered when testing the efficacy of microbial management interventions designed to increase animal welfare and food safety: these may have differential effects on livestock depending on location and timing.
•Retail poultry bacterial richness differs by season but not region.•Retail poultry bacterial types differ by season and region.•There are differential abundances of bacteria types on retail poultry by season and region.•We infer bacterial communities become homogenised in flocks by factory processing.
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