We demonstrate a voltage-controlled exchange bias effect in CoFeB/MgO/CoFeB magnetic tunnel junctions that is related to the interfacial Fe(Co)O_{x} formed between the CoFeB electrodes and the MgO ...barrier. The unique combination of interfacial antiferromagnetism, giant tunneling magnetoresistance, and sharp switching of the perpendicularly magnetized CoFeB allows sensitive detection of the exchange bias. We find that the exchange bias field can be isothermally controlled by magnetic fields at low temperatures. More importantly, the exchange bias can also be effectively manipulated by the electric field applied to the MgO barrier due to the voltage-controlled antiferromagnetic anisotropy in this system.
This paper evaluates the current status of global modeling of the organic aerosol (OA) in the troposphere and analyzes the differences between models as well as between models and observations. ...Thirty-one global chemistry transport models (CTMs) and general circulation models (GCMs) have participated in this intercomparison, in the framework of AeroCom phase II. The simulation of OA varies greatly between models in terms of the magnitude of primary emissions, secondary OA (SOA) formation, the number of OA species used (2 to 62), the complexity of OA parameterizations (gas-particle partitioning, chemical aging, multiphase chemistry, aerosol microphysics), and the OA physical, chemical and optical properties. The diversity of the global OA simulation results has increased since earlier AeroCom experiments, mainly due to the increasing complexity of the SOA parameterization in models, and the implementation of new, highly uncertain, OA sources. Diversity of over one order of magnitude exists in the modeled vertical distribution of OA concentrations that deserves a dedicated future study. Furthermore, although the OA / OC ratio depends on OA sources and atmospheric processing, and is important for model evaluation against OA and OC observations, it is resolved only by a few global models. The median global primary OA (POA) source strength is 56 Tg a−1 (range 34–144 Tg a−1) and the median SOA source strength (natural and anthropogenic) is 19 Tg a−1 (range 13–121 Tg a−1). Among the models that take into account the semi-volatile SOA nature, the median source is calculated to be 51 Tg a−1 (range 16–121 Tg a−1), much larger than the median value of the models that calculate SOA in a more simplistic way (19 Tg a−1; range 13–20 Tg a−1, with one model at 37 Tg a−1). The median atmospheric burden of OA is 1.4 Tg (24 models in the range of 0.6–2.0 Tg and 4 between 2.0 and 3.8 Tg), with a median OA lifetime of 5.4 days (range 3.8–9.6 days). In models that reported both OA and sulfate burdens, the median value of the OA/sulfate burden ratio is calculated to be 0.77; 13 models calculate a ratio lower than 1, and 9 models higher than 1. For 26 models that reported OA deposition fluxes, the median wet removal is 70 Tg a−1 (range 28–209 Tg a−1), which is on average 85% of the total OA deposition. Fine aerosol organic carbon (OC) and OA observations from continuous monitoring networks and individual field campaigns have been used for model evaluation. At urban locations, the model–observation comparison indicates missing knowledge on anthropogenic OA sources, both strength and seasonality. The combined model–measurements analysis suggests the existence of increased OA levels during summer due to biogenic SOA formation over large areas of the USA that can be of the same order of magnitude as the POA, even at urban locations, and contribute to the measured urban seasonal pattern. Global models are able to simulate the high secondary character of OA observed in the atmosphere as a result of SOA formation and POA aging, although the amount of OA present in the atmosphere remains largely underestimated, with a mean normalized bias (MNB) equal to −0.62 (−0.51) based on the comparison against OC (OA) urban data of all models at the surface, −0.15 (+0.51) when compared with remote measurements, and −0.30 for marine locations with OC data. The mean temporal correlations across all stations are low when compared with OC (OA) measurements: 0.47 (0.52) for urban stations, 0.39 (0.37) for remote stations, and 0.25 for marine stations with OC data. The combination of high (negative) MNB and higher correlation at urban stations when compared with the low MNB and lower correlation at remote sites suggests that knowledge about the processes that govern aerosol processing, transport and removal, on top of their sources, is important at the remote stations. There is no clear change in model skill with increasing model complexity with regard to OC or OA mass concentration. However, the complexity is needed in models in order to distinguish between anthropogenic and natural OA as needed for climate mitigation, and to calculate the impact of OA on climate accurately.
Delayed pollination is widely used to overcome pre‐fertilization incompatibility, but its regulatory mechanisms are unclear. When Nicotiana tabacum was cross‐pollinated with pollen of N. alata, the ...incompatibility occurring in the basal 1/4 region of the style (pollinated at anthesis: 0‐day‐old pistil) was overcome by delayed pollination (of 6‐day‐old pistil), and the morphological changes and corresponding physiological basis are explored here.
The structure and ultrastructure of the pistil were observed under fluorescence microscopy and transmission electron microscopy. Differentially expressed proteins were screened with a monoclonal antibody chip for Nicotiana, and protein expression and distribution were analysed by immunofluorescence. Cellulase and pectinase activities were tested using enzyme‐linked immunosorbent assay kits.
The style of Nicotiana is solid in the basal region and pollen tubes grow in the extracellular spaces (ECM) of the transmitting tissue (TTS) cells. Seven of the 22 identified proteins were cell wall‐associated proteins and were expressed at higher levels during pistil senescence. Cellulase and pectinase activities increased. The TTS cells in the basal 1/4 region of the 0‐day‐old style were polygonal and tightly arranged, with narrow ECM, but these were oval or partially dissolved in the 6‐day‐old pistil, leading to wider ECM and richer secretions.
The increased expression of cell wall proteins and enhanced enzyme activity during pistil senescence might partially be responsible for the cells becoming oval and the ECM enlarged, providing the morphological basis for delayed pollination overcoming the pre‐fertilization incompatibility between N. tabacum and N. alata.
The transmitting tissue cells becoming oval and the extracellular spaces enlarged in senescent pistils and play a role in overcoming pollen‐pistil incompatibility via delayed pollination.
Glioblastoma stem cells (GSCs) are implicated in tumor neovascularization, invasiveness, and therapeutic resistance. To illuminate mechanisms governing these hallmark features, we developed a de novo ...glioblastoma multiforme (GBM) model derived from immortalized human neural stem/progenitor cells (hNSCs) to enable precise system-level comparisons of pre-malignant and oncogene-induced malignant states of NSCs. Integrated transcriptomic and epigenomic analyses uncovered a PAX6/DLX5 transcriptional program driving WNT5A-mediated GSC differentiation into endothelial-like cells (GdECs). GdECs recruit existing endothelial cells to promote peritumoral satellite lesions, which serve as a niche supporting the growth of invasive glioma cells away from the primary tumor. Clinical data reveal higher WNT5A and GdECs expression in peritumoral and recurrent GBMs relative to matched intratumoral and primary GBMs, respectively, supporting WNT5A-mediated GSC differentiation and invasive growth in disease recurrence. Thus, the PAX6/DLX5-WNT5A axis governs the diffuse spread of glioma cells throughout the brain parenchyma, contributing to the lethality of GBM.
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•Comparisons of NSCs and derivative GSCs reveal elevated WNT5A and EC signature•PAX6/DLX5 bidirectionally regulates WNT5A during differentiation of GSCs into GdECs•WNT5A-mediated GdEC differentiation and EC recruitment support GSC invasive growth•Clinical studies of peritumoral/recurrent GBM reveal increased WNT5A/GdEC expression
Epigenetic activation of WNT5A expression contributes to glioblastoma tumor recurrence by promoting differentiation of glioma-derived stem cells into endothelial cells.
SUMMARY
Diabetes mellitus has the probability to impair the anastomotic healing and cause postesophagectomy anastomotic leakages but previous studies showed controversial results. This review aims to ...summary the impact of diabetes mellitus on the risk of anastomotic leakage after esophagectomy. We searched the PubMed and EMBASE databases to recognize English articles that met our eligibility criteria. Odds ratio with 95% confidence interval serves as the appropriate summarized statistic. Sensitivity analysis, meta-regression analysis, and publication bias tests were also performed to perceive potential bias risks. Finally, 16 observational studies with 12359 surgical patients were included. An overall analysis identified that diabetes mellitus was significantly associated with the risk of anastomotic leakage after esophagectomy (odds ratio = 1.63; 95% confidence interval = 1.25–2.12; P < 0.001). Further subgroup analysis showed a significant impact of diabetes mellitus in surgical populations from the Europe and America (odds ratio = 1.42; 95% confidence interval = 1.22–1.65; P < 0.001) but not in the Asian populations (odds ratio = 2.27; 95% confidence interval = 0.86–6.05; P = 0.1). The robustness of these estimates was confirmed by meta-regression analysis and sensitivity analysis. No significant publication bias exists between studies. In conclusion, this systematic review demonstrates that diabetes mellitus can be a significant risk factor of anastomotic leakage for patients undergoing esophagectomy. Our findings need to be further confirmed and modified by more well-designed worldwide multivariable analyses in the future.
Monolayer (ML) transition metal dichalcogenides (TMDs) are of great research interest due to their potential use in ultrathin electronic and optoelectronic applications. They show promise in new ...concept devices in spintronics and valleytronics. Here we present a growth study by molecular-beam epitaxy of ML and sub-ML MoSe2, an important member of TMDs, revealing its unique growth characteristics as well as the formation processes of domain boundary (DB) defects. A dramatic effect of growth temperature and post-growth annealing on DB formation is uncovered.
Abstract
For decades, supernova remnants (SNRs) have been considered the prime sources of Galactic cosmic rays (CRs). But whether SNRs can accelerate CR protons to PeV energies and thus dominate CR ...flux up to the knee is currently under intensive theoretical and phenomenological debate. The direct test of the ability of SNRs to operate as CR PeVatrons can be provided by ultrahigh-energy (UHE;
E
γ
≥ 100 TeV)
γ
-rays. In this context, the historical SNR Cassiopeia A (Cas A) is considered one of the most promising targets for UHE observations. This paper presents the observation of Cas A and its vicinity by the LHAASO KM2A detector. The exceptional sensitivity of LHAASO KM2A in the UHE band, combined with the young age of Cas A, enabled us to derive stringent model-independent limits on the energy budget of UHE protons and nuclei accelerated by Cas A at any epoch after the explosion. The results challenge the prevailing paradigm that Cas A–type SNRs are major suppliers of PeV CRs in the Milky Way.
For deep excavations in residual soils that are underlain by highly fissured or fractured rocks, it is common to observe the drawdown of the groundwater table behind the excavation, resulting in ...seepage-induced ground settlement. In this study, finite element analyses are firstly performed to assess the critical parameters that influence the ground settlement performance in residual soil deposits subjected to groundwater drawdown. The critical parameters that influence the ground settlement performance were identified as the excavation width, the excavation depth, the depth of groundwater drawdown, the thickness of the residual soil, the average SPT
N
60
value of the residual soil, the location of the moderately weathered rock, and the wall system stiffness. Subsequently, an artificial neural network (ANN) model was developed to provide estimates of the maximum ground settlement. Validation of the performance of ANN model was carried out using additional data derived from finite element analyses as well as with measured data from a number of excavation sites.
Human cytomegalovirus: taking the strain Wilkinson, Gavin W. G.; Davison, Andrew J.; Tomasec, Peter ...
Medical microbiology and immunology,
06/2015, Letnik:
204, Številka:
3
Journal Article
Recenzirano
Odprti dostop
In celebrating the 60th anniversary of the first isolation of human cytomegalovirus (HCMV), we reflect on the merits and limitations of the viral strains currently being used to develop urgently ...needed treatments. HCMV research has been dependent for decades on the high-passage strains AD169 and Towne, heavily exploiting their capacity to replicate efficiently in fibroblasts. However, the genetic integrity of these strains is so severely compromised that great caution needs to be exercised when considering their past and future use. It is now evident that wild-type HCMV strains are not readily propagated in vitro. HCMV mutants are rapidly selected during isolation in fibroblasts, reproducibly affecting gene RL13, the UL128 locus (which includes genes UL128, UL130 and UL131A) and often the U
L
/
b
′ region. As a result, the virus becomes less cell associated, altered in tropism and less pathogenic. This problem is not restricted to high-passage strains, as even low-passage strains can harbour biologically significant mutations. Cloning and manipulation of the HCMV genome as a bacterial artificial chromosome (BAC) offers a means of working with stable, genetically defined strains. To this end, the low-passage strain Merlin genome was cloned as a BAC and sequentially repaired to match the viral sequence in the original clinical sample from which Merlin was derived. Restoration of UL128L to wild type was detrimental to growth in fibroblasts, whereas restoration of RL13 impaired growth in all cell types tested. Stable propagation of phenotypically wild-type virus could be achieved only by placing both regions under conditional expression. In addition to the development of these tools, the Merlin transcriptome and proteome have been characterized in unparalleled detail. Although Merlin may be representative of the clinical agent, high-throughput whole-genome deep sequencing studies have highlighted the remarkable high level of interstrain variation present in circulating virus. There is a need to develop systems capable of addressing the significance of this diversity, free from the confounding effects of genetic changes associated with in vitro adaptation. The generation of a set of BAC clones, each containing the genome of a different HCMV strain repaired to match the sequence in the clinical sample, would provide a pathway to address the biological and clinical effects of natural variation in wild-type HCMV.
A route combining friction stir processing and subsequent rolling processing was established to fabricate 1.5–4.5vol.% carbon nanotube (CNT)-reinforced 2009Al composites. Microstructural observations ...indicated that CNTs were individually dispersed and directionally aligned in the aluminum matrix of the CNT/2009Al composites. The tube structure of the CNTs was retained and the CNT–Al interface was bonded without pores. As a result, great increases in yield strength, ultimate tensile strength, and Young’s modulus were achieved when a higher concentration of CNTs was incorporated. Moreover, the composites exhibited good ductility. In particular, 3vol.% CNT/2009Al composite exhibited an ultimate tensile strength of 600MPa and elongation of 10%, much higher strength–ductility than the corresponding values for CNT/Al composites fabricated by other processes.
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