- Readout of a dopant spin in the anisotropic quantum dot with a single magnetic ion. [Journal Article]
- JPJ Phys Condens Matter 2019 Jul 19
- Owing to exchange interaction between the exciton and magnetic ion, a quantum dot embedding&#13; a single magnetic ion is a great platform for optical control of individual spin. In particular, a…
Owing to exchange interaction between the exciton and magnetic ion, a quantum dot embedding&#13; a single magnetic ion is a great platform for optical control of individual spin. In particular, a quantum dot provides strong and sharp optical transitions, which give experimental access to spin states&#13; of an individual magnetic ion. We show, however, that physics of quantum dot excitons also complicate spin readout and optical spin manipulation in such a system. This is due to electron-hole&#13; exchange interaction in anisotropic quantum dots, which affects the polarization of the emission&#13; lines. One of the consequences is that the intensity of spectral lines in a single spectrum are not&#13; simply proportional to the population of various spin states of magnetic ion. In order to provide a&#13; solution of the above problem, we present a method of extracting both the spin polarisation degree of&#13; a neutral exciton and magnetic dopant inside a semiconductor quantum dot in an external magnetic&#13; field. Our approach is experimentally verified on a system of CdSe/ZnSe quantum dot containing a&#13; single Fe&lt;sup&gt;2+&lt;/sup&gt;ion. Both the resonant and non-resonant excitation regimes are explored resulting in a&#13; record high optical orientation efficiency of dopant spin in the former case. The proposed solutions&#13; can be easily expanded to any other system of quantum dots containing magnetic dopants.
- Effect of moisture on wheat grains lipid patterns and infection with Fusarium graminearum. [Journal Article]
- IJInt J Food Microbiol 2019 Jul 09; 306:108264
- Suitable conditions of temperature and humidity are required to maintain wheat grains quality, but during processing and storage, the grains can be exposed to adverse environmental conditions and pre…
Suitable conditions of temperature and humidity are required to maintain wheat grains quality, but during processing and storage, the grains can be exposed to adverse environmental conditions and presence of infectious fungi. Fusarium graminearum, the main causal agent of Fusarium head blight on wheat, affects crop yields and grain quality by alteration of their biochemical components and mycotoxin contamination, which reduces the possibilities of wheat end use and compromises food safety. Lipid degradation by hydrolytic, oxidative and microbial deterioration is the predominant cause of the loss of sensory acceptability, nutritional value and baking quality. The aim of this research was to determine the influence of adverse environmental conditions -as the increasing moisture - on lipid patterns of whole wheat flours contaminated with F. graminearum in relation to the infection degree. In vitro cultures of F. graminearum were carried out on wheat grains under different degrees of relative humidity (11, 50, 75 and 100%) throughout 45 days of incubation at 28 °C. The fungal biomass measured by q-PCR increased proportionally with the humidity. A decrease in the signals of saturated (palmitic and estearic) and unsaturated (oleic, linoleic and linolenic) fatty acids, analyzed as fatty acid methyl esters (FAMEs) by GC-MS, was observed in relation with the humidity and infection degree. The degradation rate of the lipids was high during the first 15 days of incubation, reaching the fatty acids content, values around 20-40% of those found in the control. From that moment on, the rate of degradation was slower or even null. It was observed that in all treatments, the linolenic acid reached the highest degradation ratio in comparison with the other fatty acids, which may be caused by the action of lipoxygenases. The lipase activity and the content of deoxynivalenol were also determinate on the flours. The lipase activity increased until day 25 of incubation reaching twice the initial value. The deoxynivalenol content also increased along incubation while fatty acids decreased. Our results demonstrated that the magnitude in the signal of fatty acids in whole wheat flours varied in relation to the degree of humidity and fungal infection of the grains from which they were obtained. Otherwise, lipids and their oxidation products are related with the pathogenesis and production of mycotoxins. These observations highlight the importance of an adequate manipulation of wheat grains on the processing chain to prevent quality changes and mycotoxins contamination.
- Glucocorticoids and Brown adipose tissue: Do glucocorticoids really inhibit thermogenesis? [Review]
- MAMol Aspects Med 2019 Jul 16
- A reduction in the thermogenic activity of brown adipose tissue (BAT) is presently discussed as a possible determinant for the development of obesity in humans. One group of endogenous factors that c…
A reduction in the thermogenic activity of brown adipose tissue (BAT) is presently discussed as a possible determinant for the development of obesity in humans. One group of endogenous factors that could potentially affect BAT activity is the glucocorticoids (e.g. cortisol). We analyse here studies examining the effects of alterations in glucocorticoid signaling on BAT recruitment and thermogenic capacity. We find that irrespective of which manipulation of glucocorticoid signaling is examined, a seemingly homogeneous picture of lowered thermogenic capacity due to glucocorticoid stimulation is apparently obtained: e.g. lowered uncoupling protein 1 (UCP1) protein levels per mg protein, and an increased lipid accumulation in BAT. However, further analyses generally indicate that these effects result from a dilution of thermogenic capacity rather than a true decrease in total capacity; the tissue may thus be said to be in a state of pseudo-atrophy. However, under conditions of very low physiological stimulation of BAT, glucocorticoids may truly inhibit Ucp1 gene expression and consequently lower total UCP1 protein levels, but the metabolic effects of this reduction are probably minor. It is thus unlikely that glucocorticoids affect organismal metabolism and induce the development of obesity through alterations of BAT activity.
- Treatment for central-peripheral rivalry-type diplopia ("dragged-fovea diplopia syndrome"). [Journal Article]
- AJAm J Ophthalmol 2019 Jul 16
- CONCLUSIONS: and relevance: CPR-type diplopia may be relieved in some patients using non-surgical treatment options of Fresnel prism or Bangerter filter. ERM peeling was surprisingly successful and should be considered.
- Plants alter their vertical root distribution rather than biomass allocation in response to changing precipitation. [Journal Article]
- EEcology 2019 Jul 19; :e02828
- Elucidating the variation of allocation pattern of ecosystem net primary productivity (NPP) and its underlying mechanisms are critically important for understanding the changes of aboveground and bel…
Elucidating the variation of allocation pattern of ecosystem net primary productivity (NPP) and its underlying mechanisms are critically important for understanding the changes of aboveground and belowground ecosystem functions. Under optimal partitioning theory, plants should allocate more NPP to the organ that acquires the most limiting resource, and this expectation has been widely used to explain and predict NPP allocation under changing precipitation. However, confirmatory evidence for this theory has mostly come from observed spatial variation in the relationship between precipitation and NPP allocation across ecosystems, rather than directly from the influences of changing precipitation on NPP allocation within systems. We performed a six-year five-level precipitation manipulation experiment in a semiarid steppe to test whether changes in NPP allocation can be explained by the optimal partitioning theory, and how water requirement of plant community is maintained if NPP allocation is unaltered. The total 30 precipitation levels (five-level × six-year) were divided into dry, nominal and wet precipitation ranges, relative to historical precipitation variation over the past six decades. We found that NPP in both aboveground (ANPP) and belowground (BNPP) increased nonlinearly as precipitation decreased, while the allocation of NPP to BNPP (fBNPP ) showed a concave quadratic relationship with precipitation. The declined fBNPP as precipitation increased in the dry range supported the optimal partitioning theory. However, in the nominal range, NPP allocation was not influenced by the changed precipitation; instead, BNPP was distributed more in the surface soil horizon (0-10 cm) as precipitation increased, and conversely more in the deeper soil layers (10-30 cm) as precipitation decreased. This response in root foraging appears to be a strategy to satisfy plant water requirements and partially explains the stable NPP allocation patterns. Overall, our results suggest that plants can adjust their vertical BNPP distribution in response to drought stress, and that only under extreme drought does the optimal partitioning theory strictly apply, highlighting the context dependency of the adaption and growth of plants under changing precipitation. This article is protected by copyright. All rights reserved.
- Safety Events and Privilege Utilization Rates in Advanced Practice Physical Therapy Compared to Traditional Primary Care: An Observational Study. [Journal Article]
- MMMil Med 2019 Jul 19
- CONCLUSIONS: These results suggest advanced practice PT has a similar safety profile to primary care. The authority to order musculoskeletal imaging and refer to other clinicians were among the most commonly utilized privileges and may be of primary importance when establishing an advanced practice PT clinic. These results support research showing advanced practice PT may lead to reductions in specialty referrals, diagnostic imaging, and pharmaceutical interventions.
- Tomato bHLH132 transcription factor controls growth and defense and is activated by Xanthomonas euvesicatoria effector XopD during pathogenesis. [Journal Article]
- MPMol Plant Microbe Interact 2019 Jul 19
- Effector-dependent manipulation of host transcription is a key virulence mechanism used by Xanthomonas species causing bacterial spot disease in tomato and pepper. Transcription activator-like (TAL) …
Effector-dependent manipulation of host transcription is a key virulence mechanism used by Xanthomonas species causing bacterial spot disease in tomato and pepper. Transcription activator-like (TAL) effectors employ novel DNA-binding domains to directly activate host transcription, whereas the non-TAL effector XopD uses a small ubiquitin-like modifier (SUMO) protease activity to represses host transcription. The targets of TAL and non-TAL effectors provide insight to the genes governing susceptibility and resistance during Xanthomonas infection. In this study, we investigated the extent to which the non-TAL effector strain Xe85-10 activates tomato transcription to gain new insight to the transcriptional circuits and virulence mechanisms associated with X. euvesicatoria pathogenesis. Using transcriptional profiling, we identified a putative basic-helix-loop-helix (bHLH) transcription factor, bHLH132, as a pathogen-responsive gene that is moderately induced by microbe-associated molecular patterns and defense hormones, and highly induced by XopD during X. euvesicatoria infection. We also found that activation of bHLH132 transcription requires XopD's SUMO protease activity. Silencing bHLH132 mRNA expression results in stunted tomato plants with enhanced susceptibility to X. euvesicatoria infection. Our work suggests that bHLH132 is required for normal vegetative growth and development, as well as resistance to X. euvesicatoria. It also suggests new transcription-based models describing XopD virulence and recognition in tomato.
- Modulating the Use of Multiple Memory Systems in Value-based Decisions with Contextual Novelty. [Journal Article]
- JCJ Cogn Neurosci 2019 Jul 19; :1-13
- With multiple learning and memory systems at its disposal, the human brain can represent the past in many ways, from extracting regularities across similar experiences (incremental learning) to stori…
With multiple learning and memory systems at its disposal, the human brain can represent the past in many ways, from extracting regularities across similar experiences (incremental learning) to storing rich, idiosyncratic details of individual events (episodic memory). The unique information carried by these neurologically distinct forms of memory can bias our behavior in different directions, raising crucial questions about how these memory systems interact to guide choice and the factors that cause one to dominate. Here, we devised a new approach to estimate how decisions are independently influenced by episodic memories and incremental learning. Furthermore, we identified a biologically motivated factor that biases the use of different memory types-the detection of novelty versus familiarity. Consistent with computational models of cholinergic memory modulation, we find that choices are more influenced by episodic memories following the recognition of an unrelated familiar image but more influenced by incrementally learned values after the detection of a novel image. Together this work provides a new behavioral tool enabling the disambiguation of key memory behaviors thought to be supported by distinct neural systems while also identifying a theoretically important and broadly applicable manipulation to bias the arbitration between these two sources of memories.
- Stability Limit of Electrified Droplets. [Journal Article]
- PRPhys Rev Lett 2019 Jun 21; 122(24):244501
- In many physical processes, including cloud electrification, electrospray, and demulsification, droplets and bubbles are exposed to electric fields and may either remain whole or burst in response to…
In many physical processes, including cloud electrification, electrospray, and demulsification, droplets and bubbles are exposed to electric fields and may either remain whole or burst in response to electrical stresses. Determining the stability limit of a droplet exposed to an external electric field has been a long-standing mathematical challenge, and the only analytical treatment to date is an approximate calculation for the particular case of a free-floating droplet. Here we demonstrate, experimentally and theoretically, that the stability limit of a conducting droplet or bubble exposed to an external electric field is described by a power law with broad generality that, in practice, applies to the cases in which the droplet or bubble is pinned or sliding on a conducting surface or free floating. This power law can facilitate the design of devices for liquid manipulation via a simple formula that captures the parameter range of bubbles and droplets that can be supported on electrified surfaces.
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- Emergence of the Vortex State in Confined Ferroelectric Heterostructures. [Journal Article]
- AMAdv Mater 2019 Jul 19; :e1901014
- The manipulation of charge and lattice degrees of freedom in atomically precise, low-dimensional ferroelectric superlattices can lead to exotic polar structures, such as a vortex state. The role of i…
The manipulation of charge and lattice degrees of freedom in atomically precise, low-dimensional ferroelectric superlattices can lead to exotic polar structures, such as a vortex state. The role of interfaces in the evolution of the vortex state in these superlattices (and the associated electrostatic and elastic boundary conditions they produce) has remained unclear. Here, the toroidal state, arranged in arrays of alternating clockwise/counterclockwise polar vortices, in a confined SrTiO3 /PbTiO3 /SrTiO3 trilayer is investigated. By utilizing a combination of transmission electron microscopy, synchrotron-based X-ray diffraction, and phase-field modeling, the phase transition as a function of layer thickness (number of unit cells) demonstrates how the vortex state emerges from the ferroelectric state by varying the thickness of the confined PbTiO3 layer. Intriguingly, the vortex state arises at head-to-head domain boundaries in ferroelectric a1 /a2 twin structures. In turn, by varying the total number of PbTiO3 layers (moving from trilayer to superlattices), it is possible to manipulate the long-range interactions among multiple confined PbTiO3 layers to stabilize the vortex state. This work provides a new understanding of how the different energies work together to produce this exciting new state of matter and can contribute to the design of novel states and potential memory applications.