Abstract
Optical characteristics of luminescent materials, such as emission profile and lifetime, play an important role in their applications in optical data storage, document security, diagnostics, ...and therapeutics. Lanthanide-doped upconversion nanoparticles are particularly suitable for such applications due to their inherent optical properties, including large anti-Stokes shift, distinguishable spectroscopic fingerprint, and long luminescence lifetime. However, conventional upconversion nanoparticles have a limited capacity for information storage or complexity to prevent counterfeiting. Here, we demonstrate that integration of long-lived Mn
2+
upconversion emission and relatively short-lived lanthanide upconversion emission in a particulate platform allows the generation of binary temporal codes for efficient data encoding. Precise control of the particle’s structure allows the excitation feasible both under 980 and 808 nm irradiation. We find that the as-prepared Mn
2+
-doped nanoparticles are especially useful for multilevel anti-counterfeiting with high-throughput rate of authentication and without the need for complex time-gated decoding instrumentation.
We present Searches After Gravitational-waves Using ARizona Observatories (SAGUARO), a comprehensive effort dedicated to the discovery and characterization of optical counterparts to ...gravitational-wave (GW) events. SAGUARO utilizes ground-based facilities ranging from 1.5 to 10 m in diameter, located primarily in the Northern Hemisphere. We provide an overview of SAGUARO's telescopic resources, its pipeline for transient detection, and its database for candidate visualization. We describe SAGUARO's discovery component, which utilizes the 5 deg2 field of view optical imager on the Mt. Lemmon 1.5 m telescope, reaching limits of 21.3 AB mag while rapidly tiling large areas. We also describe the follow-up component of SAGUARO, used for rapid vetting and monitoring of optical candidates. With the onset of Advanced LIGO/Virgo's third observing run, we present results from the first three SAGUARO searches following the GW events S190408an, S190425z and S190426c, which serve as a valuable proof-of-concept of SAGUARO. We triggered and searched 15, 60, and 60 deg2 respectively, 17.6, 1.4, and 41.8 hr after the initial GW alerts. We covered 7.8%, 3.0%, and 5.1% of the total probability within the GW event localizations, reaching 3 limits of 19.8, 21.3, and 20.8 AB mag, respectively. Although no viable counterparts associated with these events were found, we recovered six known transients and ruled out five potential candidates. We also present Large Binocular Telescope spectroscopy of PS19eq/SN2019ebq, a promising kilonova candidate that was later determined to be a supernova. With the ability to tile large areas and conduct detailed follow-up, SAGUARO represents a significant addition to GW counterpart searches.
The ferromagnet/oxide interface is key to developing emerging multiferroic and spintronic technologies with new functionality. Here we probe the Fe/MgO interface magnetization, and identify a new ...exchange bias phenomenon manifested only in the interface spin system, and not in the bulk. The interface magnetization exhibits a pronounced exchange bias, and the hysteresis loop is shifted entirely to one side of the zero field axis. However, the bulk magnetization does not, in marked contrast to typical systems where exchange bias is manifested in the net magnetization. This reveals the existence of an antiferromagnetic exchange pinning layer at the interface, identified here as FeO patches that exist even for a nominally 'clean' interface. These results demonstrate that atomic moments at the interface are non-collinear with the bulk magnetization, and therefore may affect the net anisotropy or serve as spin scattering sites. We control the exchange bias magnitude by varying the interface oxygen concentration and Fe-O bonding.
Summary
What is known and objective
A series of studies have indicated that valproic acid (VPA) plasma concentration decreased rapidly when used concomitantly with carbapenem antibiotics, including ...meropenem (MEPM), imipenem and panipenem, which may increase the risk of seizure breakthrough. However, the cause for the change in VPA pharmacokinetics is unclear. A retrospective analysis of VPA therapeutic drug monitoring (TDM) records was performed to investigate this VPA pharmacokinetics drug–drug interaction.
Methods
Three hundred and eighty one VPA TDM records from the Department of Neurosurgery of Xiangya Hospital from January 2012 to December 2014 were collected. The VPA TDM records were categorized by VPA and MEPM daily dosages in grams/day (g/day). A comparison of VPA plasma levels among different groups was performed to investigate the change in VPA level in this drug interaction.
Results and discussion
Remarkable decreases in VPA plasma level were observed when the drug was used concomitantly with MEPM in both 1.2 g/d and 1.6 g/d VPA groups (67·3 ± 4·6 μg/mL, n = 21 vs. 15·3 ± 1·9 μg/mL, n = 15, P < 0·001; 67·6 ± 1·2 μg/mL vs. 18·1 ± 2·6 μg/mL, n = 38, P < 0·001). No significant difference in VPA plasma concentrations was observed between the 1·2 g/day VPA + MEPM, 1·6 g/day VPA + MEPM and 2·0 g/day VPA + MEPM groups (15·3 ± 1·9 μg/mL, n = 15 vs. 18·1 ± 2·6 μg/mL, n = 38 vs. 9·0 ± 3·0 μg/mL, n = 7; P = 0·252). The decrease in VPA concentration was independent of MEPM daily dose (14·0 ± 5·1 μg/mL, n = 4 for high MEPM daily dose vs. 16·5 ± 1·9 μg/mL, n = 56 for low MEPM daily dose; P = 0·729). After discontinuation of MEPM for more than 7 days, VPA plasma concentration recovered to a value comparable to that before MPEM initiation (69·7 ± 4·2 μg/mL, n = 21 vs. 51·2 ± 8·1 μg/mL, n = 9; P = 0·48).
What is new and conclusion
This is the first study using a large number of VPA TDM records to investigate the change in VPA levels caused by concomitant use of MEPM. Our results imply that the decrease in drug concentration cannot be reversed by increasing VPA dose. Moreover, MEPM daily dose did not influence the drop in VPA plasma level. At least 7 days are required for the recovery of VPA plasma concentration after discontinuation of MEPM.
The magnitude of decrease in VPA plasma concentration was independent of VPA and MEPM daily dose in this drug‐drug interaction.
Abstract β-Amyloid (Aβ) plaques in Alzheimer (AD) brains are surrounded by severe dendritic and axonal changes, including local spine loss, axonal swellings and distorted neurite trajectories. ...Whether and how plaques induce these neuropil abnormalities remains unknown. We tested the hypothesis that oligomeric assemblies of Aβ, seen in the periphery of plaques, mediate the neurodegenerative phenotype of AD by triggering activation of the enzyme GSK-3β, which in turn appears to inhibit a transcriptional program mediated by CREB. We detect increased activity of GSK-3β after exposure to oligomeric Aβ in neurons in culture, in the brain of double transgenic APP/tau mice and in AD brains. Activation of GSK-3β, even in the absence of Aβ, is sufficient to produce a phenocopy of Aβ-induced dendritic spine loss in neurons in culture, while pharmacological inhibition of GSK-3β prevents spine loss and increases expression of CREB-target genes like BDNF. Of note, in transgenic mice GSK-3β inhibition ameliorated plaque-related neuritic changes and increased CREB-mediated gene expression. Moreover, GSK-3β inhibition robustly decreased the oligomeric Aβ load in the mouse brain. All these findings support the idea that GSK3β is aberrantly activated by the presence of Aβ, and contributes, at least in part, to the neuronal anatomical derangement associated with Aβ plaques in AD brains and to Aβ pathology itself.
Flexible thermoelectric (TE) materials have wide applications in fabricating portable/wearable devices owing to the advantages of being bendable, small size, and lightweight. Inorganic material–based ...flexible thin films have attracted much attention owing to their high TE performance. So far, developing high TE properties and environment friendly flexible thin films for practical applications is still a considerable challenge. Copper selenide (Cu2Se) is a non-toxic and low-cost material, providing relatively safe TE modules for thin film devices. In this work, Cu2Se-based thin films with single crystal phase have been fabricated successfully at a flexible substrate by an efficient layer-by-layer combination reaction method. By optimizing the composition, a high power factor of 5.3 μWcm−1K−2 and dimensionless figure of merit value of 0.35 with low thermal conductivity are achieved at room temperature. Through bending tests, it has been shown that the prepared thin films possess good flexibility and the designed flexible device displays stable output power, which demonstrates the potential of inorganic TE materials to be mountable on flexible/wearable substrates for energy harvesting and management devices.
The well-crystallized Cu2Se thermoelectric thin films have been synthesized via an efficient layer-by-layer combination reaction method, and the high power factor of 5.3 μWcm−1K−2 and ZT value of 0.35 with low thermal conductivity are achieved at room temperature by optimizing the composition. Cu2Se, copper selenide; ZT, dimensionless figure of merit. Display omitted
•The layer-by-layer combination reaction method was used for preparing high-performance copper selenide (Cu2Se) thin films.•The self-assembled growth of Cu2Se with single crystal phase was successfully realized.•A high power factor of 5.3 μWcm−1K−2 and dimensionless figure of merit value of 0.35 are achieved at room temperature.•The thin film possesses good flexibility, and the designed flexible device displays stable output power.
Support vector machines (SVMs) were used to develop QSAR models that correlate molecular structures to their toxicity and bioactivities. The performance and predictive ability of SVM are investigated ...and compared with other methods such as multiple linear regression and radial basis function neural network methods. In the present study, two different data sets were evaluated. The first one involves an application of SVM to the development of a QSAR model for the prediction of toxicities of 153 phenols, and the second investigation deals with the QSAR model between the structures and the activities of a set of 85 cyclooxygenase 2 (COX-2) inhibitors. For each application, the molecular structures were described using either the physicochemical parameters or molecular descriptors. In both studied cases, the predictive ability of the SVM model is comparable or superior to those obtained by MLR and RBFNN. The results indicate that SVM can be used as an alternative powerful modeling tool for QSAR studies.
Dorsal root ganglia (DRG) neurons regenerate spontaneously after traumatic or surgical injury. Long noncoding RNAs (lncRNAs) are involved in various biological regulation processes. Conditions of ...lncRNAs in DRG neuron injury deserve to be further investigated. Transcriptomic analysis was performed by high-throughput Illumina HiSeq2500 sequencing to profile the differential genes in L4-L6 DRGs following rat sciatic nerve tying. A total of 1,228 genes were up-regulated and 1,415 down-regulated. By comparing to rat lncRNA database, 86 known and 26 novel lncRNA genes were found to be differential. The 86 known lncRNA genes modulated 866 target genes subject to gene ontology (GO) and KEGG enrichment analysis. The genes involved in the neurotransmitter status of neurons were downregulated and those involved in a neuronal regeneration were upregulated. Known lncRNA gene rno-Cntnap2 was downregulated. There were 13 credible GO terms for the rno-Cntnap2 gene, which had a putative function in cell component of voltage-gated potassium channel complex on the cell surface for neurites. In 26 novel lncRNA genes, 4 were related to 21 mRNA genes. A novel lncRNA gene AC111653.1 improved rno-Hypm synthesizing huntingtin during sciatic nerve regeneration. Real time qPCR results attested the down-regulation of rno-Cntnap lncRNA gene and the upregulation of AC111653.1 lncRNA gene. A total of 26 novel lncRNAs were found. Known lncRNA gene rno-Cntnap2 and novel lncRNA AC111653.1 were involved in neuropathic pain of DRGs after spared sciatic nerve injury. They contributed to peripheral nerve regeneration via the putative mechanisms.
Assessing the concentration of potentially harmful heavy metals in the soil of urban parks is imperative in order to evaluate the potential risks to residents and tourists. To date, little research ...on soil pollution in China’s urban parks has been conducted. To identify the concentrations and sources of heavy metals, and to assess the soil environmental quality, samples were collected from 30 urban parks located in the city of Beijing. Subsequently, the concentrations of Cu, Ni, Pb and Zn in the samples were analyzed. The investigation revealed that the accumulations of Cu and Pb were readily apparent in the soils. The integrated pollution index (IPI) of these four metals ranged from 0.97 to 9.21, with the highest IPI in the densely populated historic center district (HCD). Using multivariate statistic approaches (principal components analysis and hierarchical cluster analysis), two factors controlling the heavy metal variability were obtained, which accounted for nearly 80% of the total variance. Nickel and Zn levels were controlled by parent material in the soils, whereas Cu, Pb and, in part, Zn were accounted for mainly by anthropogenic activities. The findings presented here indicate that the location and the age of the park are important factors in determining the extent of heavy metal, particularly Cu and Pb, pollution. In addition, the accumulation of Zn did not appear to reach pollution levels, and no obvious pollution by Ni was observed in the soils of the parks in Beijing.
PDF
