Self Assembled II-VI Magnetic Quantum Dot as a Voltage-Controlled Spin-Filter

A key element in the emergence of a full spintronics technology is the development of voltage controlled spin filters to selectively inject carriers of desired spin into semiconductors. We previously demonstrated a prototype of such a device using a II-VI dilute-magnetic semiconductor quantum well which, however, still required an external magnetic field to generate the level splitting. Recent theory suggests that spin selection may be achievable in II-VI paramagnetic semiconductors without external magnetic field through local carrier mediated ferromagnetic interactions. We present the first experimental observation of such an effect using non-magnetic CdSe self-assembled quantum dots in a paramagnetic (Zn,Be,Mn)Se barrier.Comment: 4 pages, 4 figure

The 2017 EULAR standardised procedures for ultrasound imaging in rheumatology

BACKGROUND: In 2001, the European League Against Rheumatism developed and disseminated the first guidelines for musculoskeletal (MS) ultrasound (US) in rheumatology. Fifteen years later, the dramatic expansion of new data on MSUS in the literature coupled with technological developments in US imaging has necessitated an update of these guidelines.OBJECTIVES: To update the existing MSUS guidelines in rheumatology as well as to extend their scope to other anatomic structures relevant for rheumatology.METHODS: The project consisted of the following steps: (1) a systematic literature review of MSUS evaluable structures; (2) a Delphi survey among rheumatologist and radiologist experts in MSUS to select MS and non-MS anatomic structures evaluable by US that are relevant to rheumatology, to select abnormalities evaluable by US and to prioritise these pathologies for rheumatology and (3) a nominal group technique to achieve consensus on the US scanning procedures and to produce an electronic illustrated manual (ie, App of these procedures).RESULTS: Structures from nine MS and non-MS areas (ie, shoulder, elbow, wrist and hand, hip, knee, ankle and foot, peripheral nerves, salivary glands and vessels) were selected for MSUS in rheumatic and musculoskeletal diseases (RMD) and their detailed scanning procedures (ie, patient position, probe placement, scanning method and bony/other landmarks) were used to produce the App. In addition, US evaluable abnormalities present in RMD for each anatomic structure and their relevance for rheumatology were agreed on by the MSUS experts.CONCLUSIONS: This task force has produced a consensus-based comprehensive and practical framework on standardised procedures for MSUS imaging in rheumatology

The geography of biodiversity change in marine and terrestrial assemblages

This work was supported by funding to the sChange working group through sDiv, the synthesis center of iDiv, the German Centre for Integrative Biodiversity Research Halle-Jena-Leipzig, funded by the German Research Foundation (FZT 118). S.A.B., H.B., J.M.C., J.H., and M.W. were supported by the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig. S.R.S. was supported by U.S. National Science Foundation grant 1400911. LHA was supported by Fundação para a Ciência e Tecnologia, Portugal (POPH/FSE SFRH/BD/90469/2012), and by the Jane and Aatos Erkko Foundation. M.D. was supported by a Leverhulme Trust Fellowship. A.E.M., F.M., and M.D. were supported by ERC AdG BioTIME 250189 and PoC BioCHANGE 727440. A.G. is supported by the Liber Ero Chair in Biodiversity Conservation.Human activities are fundamentally altering biodiversity. Projections of declines at the global scale are contrasted by highly variable trends at local scales, suggesting that biodiversity change may be spatially structured. Here, we examined spatial variation in species richness and composition change using more than 50,000 biodiversity time series from 239 studies and found clear geographic variation in biodiversity change. Rapid compositional change is prevalent, with marine biomes exceeding and terrestrial biomes trailing the overall trend. Assemblage richness is not changing on average, although locations exhibiting increasing and decreasing trends of up to about 20% per year were found in some marine studies. At local scales, widespread compositional reorganization is most often decoupled from richness change, and biodiversity change is strongest and most variable in the oceans.PostprintPostprintPeer reviewe

Mapping human pressures on biodiversity across the planet uncovers anthropogenic threat complexes

Abstract Climate change and other anthropogenic drivers of biodiversity change are unequally distributed across the world. Overlap in the distributions of different drivers have important implications for biodiversity change attribution and the potential for interactive effects. However, the spatial relationships among different drivers and whether they differ between the terrestrial and marine realm has yet to be examined. We compiled global gridded datasets on climate change, land-use, resource exploitation, pollution, alien species potential and human population density. We used multivariate statistics to examine the spatial relationships among the drivers and to characterize the typical combinations of drivers experienced by different regions of the world. We found stronger positive correlations among drivers in the terrestrial than in the marine realm, leading to areas with high intensities of multiple drivers on land. Climate change tended to be negatively correlated with other drivers in the terrestrial realm (e.g. in the tundra and boreal forest with high climate change but low human use and pollution), whereas the opposite was true in the marine realm (e.g. in the Indo-Pacific with high climate change and high fishing). We show that different regions of the world can be defined by Anthropogenic Threat Complexes (ATCs), distinguished by different sets of drivers with varying intensities. We identify 11 ATCs that can be used to test hypotheses about patterns of biodiversity and ecosystem change, especially about the joint effects of multiple drivers. Our global analysis highlights the broad conservation priorities needed to mitigate the impacts of anthropogenic change, with different priorities emerging on land and in the ocean, and in different parts of the world.Peer reviewe

Involvement of a specificity proteins-binding element in regulation of basal and estrogen-induced transcription activity of the BRCA1 gene

INTRODUCTION:Increased estrogen level has been regarded to be a risk factor for breast cancer. However, estrogen has also been shown to induce the expression of the tumor suppressor gene, BRCA1. Upregulation of BRCA1 is thought to be a feedback mechanism for controlling DNA repair in proliferating cells. Estrogens enhance transcription of target genes by stimulating the association of the estrogen receptor (ER) and related coactivators to estrogen response elements or to transcription complexes formed at activator protein (AP)-1 or specificity protein (Sp)-binding sites. Interestingly, the BRCA1 gene lacks a consensus estrogen response element. We previously reported that estrogen stimulated BRCA1 transcription through the recruitment of a p300/ER-alpha complex to an AP-1 site harbored in the proximal BRCA1 promoter. The purpose of the study was to analyze the contribution of cis-acting sites flanking the AP-1 element to basal and estrogen-dependent regulation of BRCA1 transcription.METHODS:Using transfection studies with wild-type and mutated BRCA1 promoter constructs, electromobility binding and shift assays, and DNA-protein interaction and chromatin immunoprecipitation assays, we investigated the role of Sp-binding sites and cAMP response element (CRE)-binding sites harbored in the proximal BRCA1 promoter.RESULTS:We report that in the BRCA1 promoter the AP-1 site is flanked upstream by an element (5'-GGGGCGGAA-3') that recruits Sp1, Sp3, and Sp4 factors, and downstream by a half CRE-binding motif (5'-CGTAA-3') that binds CRE-binding protein. In ER-alpha-positive MCF-7 cells and ER-alpha-negative Hela cells expressing exogenous ER-alpha, mutation of the Sp-binding site interfered with basal and estrogen-induced BRCA1 transcription. Conversely, mutation of the CRE-binding element reduced basal BRCA1 promoter activity but did not prevent estrogen activation. In combination with the AP-1/CRE sites, the Sp-binding domain enhanced the recruitment of nuclear proteins to the BRCA1 promoter. Finally, we report that the MEK1 (mitogen-activated protein kinase kinase-1) inhibitor PD98059 attenuated the recruitment of Sp1 and phosphorylated ER-alpha, respectively, to the Sp and AP-1 binding element.CONCLUSION:These cumulative findings suggest that the proximal BRCA1 promoter segment comprises cis-acting elements that are targeted by Sp-binding and CRE-binding proteins that contribute to regulation of BRCA1 transcription.This item is part of the UA Faculty Publications collection. For more information this item or other items in the UA Campus Repository, contact the University of Arizona Libraries at [email protected]

Duration of Coherence Intervals in Electrical Brain Activity in Perceptual Organization

We investigated the relationship between visual experience and temporal intervals of synchronized brain activity. Using high-density scalp electroencephalography, we examined how synchronized activity depends on visual stimulus information and on individual observer sensitivity. In a perceptual grouping task, we varied the ambiguity of visual stimuli and estimated observer sensitivity to this variation. We found that durations of synchronized activity in the beta frequency band were associated with both stimulus ambiguity and sensitivity: the lower the stimulus ambiguity and the higher individual observer sensitivity the longer were the episodes of synchronized activity. Durations of synchronized activity intervals followed an extreme value distribution, indicating that they were limited by the slowest mechanism among the multiple neural mechanisms engaged in the perceptual task. Because the degree of stimulus ambiguity is (inversely) related to the amount of stimulus information, the durations of synchronous episodes reflect the amount of stimulus information processed in the task. We therefore interpreted our results as evidence that the alternating episodes of desynchronized and synchronized electrical brain activity reflect, respectively, the processing of information within local regions and the transfer of information across regions

Multidimensional Recording (MDR) and Data Sharing: An Ecological Open Research and Educational Platform for Neuroscience

Primate neurophysiology has revealed various neural mechanisms at the single-cell level and population level. However, because recording techniques have not been updated for several decades, the types of experimental design that can be applied in the emerging field of social neuroscience are limited, in particular those involving interactions within a realistic social environment. To address these limitations and allow more freedom in experimental design to understand dynamic adaptive neural functions, multidimensional recording (MDR) was developed. MDR obtains behavioral, neural, eye position, and other biological data simultaneously by using integrated multiple recording systems. MDR gives a wide degree of freedom in experimental design because the level of behavioral restraint is adjustable depending on the experimental requirements while still maintaining the signal quality. The biggest advantage of MDR is that it can provide a stable neural signal at higher temporal resolution at the network level from multiple subjects for months, which no other method can provide. Conventional event-related analysis of MDR data shows results consistent with previous findings, whereas new methods of analysis can reveal network mechanisms that could not have been investigated previously. MDR data are now shared in the public server Neurotycho.org. These recording and sharing methods support an ecological system that is open to everyone and will be a valuable and powerful research/educational platform for understanding the dynamic mechanisms of neural networks

Low Frequency Vibrations Disrupt Left-Right Patterning in the Xenopus Embryo

The development of consistent left-right (LR) asymmetry across phyla is a fascinating question in biology. While many pharmacological and molecular approaches have been used to explore molecular mechanisms, it has proven difficult to exert precise temporal control over functional perturbations. Here, we took advantage of acoustical vibration to disrupt LR patterning in Xenopus embryos during tightly-circumscribed periods of development. Exposure to several low frequencies induced specific randomization of three internal organs (heterotaxia). Investigating one frequency (7 Hz), we found two discrete periods of sensitivity to vibration; during the first period, vibration affected the same LR pathway as nocodazole, while during the second period, vibration affected the integrity of the epithelial barrier; both are required for normal LR patterning. Our results indicate that low frequency vibrations disrupt two steps in the early LR pathway: the orientation of the LR axis with the other two axes, and the amplification/restriction of downstream LR signals to asymmetric organs