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Using a high-throughput sequencing (HTS) approach, we report the discovery of a new alphasatellite identified in a winter barley plant collected in France in 2022 that was also infected by wheat dwarf virus (WDV). The presence of the satellite and of WDV was confirmed by several independent PCR assays, and the complete genome sequence was determined. The circular satellite genome is 1424 nt long and shows typical hallmarks of members of the subfamily Geminialphasatellitinae, including a replication-associated hairpin with a CAGTATTAC sequence and a Rep-encoding open reading frame (ORF). It also possesses a second ORF, embedded in a different frame within the Rep ORF, which is also observed in clecrusatellites and a few other members of the family Alphasatellitidae. Pairwise sequence comparisons and phylogenetic analysis showed that this satellite represents a novel species. Its closest relatives are in the genus Colecusatellite, but it likely represents a new genus given its divergence from other genera of the subfamily Geminialphasatellitinae. Given that WDV was the only virus observed in coinfection with the satellite, the name "wheat dwarf virus-associated alphasatellite" is proposed for this novel agent. [ABSTRACT FROM AUTHOR]

This study investigates the effect of microstructure on short-term and long-term oxidation behaviours of GH3536 superalloy fabricated by laser powder bed fusion (LPBF), in which the superalloy is isothermally oxidised at 950 °C for 6 h and 500 h in air. The LPBF sample exhibits improved oxidation resistance compared with a wrought counterpart after long-term exposure. The effect of microstructure diversity between LPBF and wrought samples on oxidation behaviour is discussed. The cellular structure produced during the LPBF process acts as a rapid diffusion path to accelerate the formation of a protective film in the initial stage, leading to an enhancement in oxidation resistance for extended exposure. [ABSTRACT FROM AUTHOR]

Laser powder bed fusion (LPBF) is an emerging additive manufacturing technique that is currently adopted by a number of industries for its ability to directly fabricate complex near-net-shaped components with minimal material wastage. Two major limitations of LPBF, however, are that the process inherently produces components containing some amount of porosity and that fabricated components tend to suffer from poor repeatability. While recent advances have allowed the porosity level to be reduced to a minimum, consistent porosity-free fabrication remains elusive. Therefore, it is important to understand how porosity affects mechanical properties in alloys fabricated this way in order to inform the safe design and application of components. To this aim, this article will review recent literature on the effects of porosity on tensile properties, fatigue life, impact and fracture toughness, creep response, and wear behavior. As the number of alloys that can be fabricated by this technology continues to grow, this overview will mainly focus on four alloys that are commonly fabricated by LPBF—Ti-6Al-4 V, Inconel 718, AISI 316L, and AlSi10Mg. [ABSTRACT FROM AUTHOR]

In this study, the influence that porosities play on the mechanical properties of Ti-6Al-4V parts fabricated by laser powder bed fusion (LPBF) was investigated with the aim of improving process efficiency of the LPBF process by establishing the resulting trade-offs to component quality. It was found that build times can be substantially reduced by using higher layer thickness parameters without a significant detriment to mechanical properties. Where porosities formed, spherical pores tend to have a marginal effect on Young's modulus, yield strength, tensile strength, and uniform elongation as these properties can be approximated linearly using the rule of mixtures assuming null strength pores. However, such pores were found to be otherwise more detrimental to total elongation and toughness. Conversely, lack of fusion pores are extremely detrimental and should be avoided. Thus, it is proposed that when building a component, different process parameters can be used at different regions of the component to maximize process efficiency without compromising its overall function. For instance, for surfaces, a highly optimized parameter set with lower layer thickness can be used. At regions with minimal stress distribution during service, a large layer thickness parameter set where the resulting mechanical properties is sufficient can be used. [ABSTRACT FROM AUTHOR]

A novel coaxial electron beam wire feeding additive manufacturing technology (CAEBWAM) was proposed in our previous work to refine the microstructure and improve the mechanical properties of titanium alloys. In the present work, different post-heat treatments were performed to understand the microstructure evolution and the resultant mechanical properties of CAEBWAMed Ti-6Al-4V alloy. The as-built sample was dominated by equiaxed prior β microstructure, with the first several deposited layers containing columnar prior β grain morphology. The as-built alloy showed a mixed microstructure composed of large α′ martensite and fine α + β lamella. As the annealing temperature was increased, α′ martensite decomposed into α + β phase, while the width of the α lamellae increased, causeing an increase in the ductility and a decrease in the strength. [ABSTRACT FROM AUTHOR]

The long production time required for large-scale parts fabricated by laser powder bed fusion (LPBF) tends to induce cracks, distortions, and overheating problems. In this work, to address these challenges, we explored and established a suitable strategy for producing large AlSi10Mg components. The platform temperatures to prevent cracks and distortions were firstly determined. Then, the in situ aging behavior was investigated for samples under various platform temperatures and holding times. Our results revealed that platform temperatures of 150°C and 200°C can effectively prevent cracks and minimize distortions. Besides, using 150°C, samples can reach peak hardness with a holding time less than 13 h. In comparison, those samples produced with a holding time longer than 13 h at 150°C and 200°C show obvious over-aging responses and thus lower hardness. However, such a hardness impoverishment can be recovered by using a T6 post-process heat-treatment. [ABSTRACT FROM AUTHOR]

In this work, the effects of nominal reductions during forging experiments on microstructures, tensile and fatigue properties of Ti-6Al-4V have been investigated. The microstructure of the starting material was a combination of equiaxed and lamellar α phases. With further deformation and annealing heat treatment, the volume fraction of globular primary α increased by about 20% as the nominal reduction increased from 10 to 50%. More notably, the ultimate tensile stress and yield stress were increased by approximately 50 MPa, and the ductility remained constant, with the nominal reduction from 10 up to 50%. Further detailed characterization revealed that the improvement in tensile and fatigue properties could be attributed to the reduction in the effective slip length, increase in the interface density, and realignment of the (0002) planes with the tensile axis. [ABSTRACT FROM AUTHOR]

Using gas flow to reduce laser plume attenuation is critical in the process control of laser powder bed fusion (LPBF) of metal powders. First, this work investigated Hastelloy X (HX) samples built at different gas flow speeds. Higher porosity with lack of fusion defects was found in the samples built at lower gas flow speeds, which indicates a significant influence of laser plume attenuation. Then, particle pickup experiments were conducted to investigate the limit of further increasing the gas flow speed without disturbing the powder bed. Eight different powders of four alloys (Al, Ti, steel, and Ni) with mean sizes ranging from 25 µm to 118 µm were studied. A model was introduced to predict the pickup speeds of different powders. Lastly, a method based on porosity and particle pickup speed was proposed for the reference of setting the lower and upper limits of gas flow speed in LPBF. [ABSTRACT FROM AUTHOR]

The correct differentiation of oligodendrocyte precursor cells (OPCs) is essential for the myelination and remyelination processes in the central nervous system. Determining the regulatory mechanism is fundamental to the treatment of demyelinating diseases. By analyzing the RNA sequencing data of different neural cells, we found that cyclin-dependent kinase 18 (CDK18) is exclusively expressed in oligodendrocytes. In vivo studies showed that the expression level of CDK18 gradually increased along with myelin formation during development and in the remyelination phase in a lysophosphatidylcholine-induced demyelination model, and was distinctively highly expressed in oligodendrocytes. In vitro overexpression and interference experiments revealed that CDK18 directly promotes the differentiation of OPCs, without affecting their proliferation or apoptosis. Mechanistically, CDK18 activated the RAS/mitogen-activated protein kinase kinase 1/extracellular signal-regulated kinase pathway, thus promoting OPC differentiation. The results of the present study suggest that CDK18 is a promising cell-type specific target to treat demyelinating disease. [ABSTRACT FROM AUTHOR]

The differentiation and maturation of oligodendrocyte precursor cells (OPCs) is essential for myelination and remyelination in the CNS. The failure of OPCs to achieve terminal differentiation in demyelinating lesions often results in unsuccessful remyelination in a variety of human demyelinating diseases. However, the molecular mechanisms controlling OPC differentiation under pathological conditions remain largely unknown. Myt1L (myelin transcription factor 1-like), mainly expressed in neurons, has been associated with intellectual disability, schizophrenia, and depression. In the present study, we found that Myt1L was expressed in oligodendrocyte lineage cells during myelination and remyelination. The expression level of Myt1L in neuron/glia antigen 2-positive (NG2+) OPCs was significantly higher than that in mature CC1+ oligodendrocytes. In primary cultured OPCs, overexpression of Myt1L promoted, while knockdown inhibited OPC differentiation. Moreover, Myt1L was potently involved in promoting remyelination after lysolecithin-induced demyelination in vivo. ChIP assays showed that Myt1L bound to the promoter of Olig1 and transcriptionally regulated Olig1 expression. Taken together, our findings demonstrate that Myt1L is an essential regulator of OPC differentiation, thereby supporting Myt1L as a potential therapeutic target for demyelinating diseases. [ABSTRACT FROM AUTHOR]

Multiple sclerosis (MS) is a classical inflammatory demyelinating disease of the central nervous system (CNS). Microglia are the main resident immune cells in the CNS and are closely associated with the pathogenesis of MS. In the present study, we found that miR-30a was highly expressed in jellyfish-like microglia in chronic active lesions of MS patients, as well as in the microglia of mice with experimental autoimmune encephalomyelitis (EAE) at the chronic phase. In vitro, the conditioned supernatant of mouse microglia overexpressing miR-30a promoted the apoptosis of oligodendrocyte precursor cells (OPCs), and inhibited OPC differentiation. In vivo, overexpressing miR-30a in transplanted microglia exacerbated the progression of EAE. Overexpression and knock-down experiments in primary cultured mouse microglia showed that miR-30a increased the expression of IL-1β and iNOS, which are pro-inflammatory, while inhibiting the expression of Ym-1 and CD206. Mechanistically, miR-30a inhibited the expression of Ppargc1b, which is the co-activator of peroxisome proliferator-activated receptor gamma, resulting in pro-inflammatory effects. Our work shows that miR-30a is an important regulator of the inflammatory response in microglia, and may be a promising therapeutic target for inflammatory diseases like MS in the CNS. [ABSTRACT FROM AUTHOR]

Heat-treated Ti-6Al-4V forged bar with colony microstructure was machined into double-cone-shaped samples for a series of isothermal uniaxial compression test at 1223 K (950 °C) with varying constant crosshead speeds of 12.5, 1.25, and 0.125 mms to a height reduction of 70 pct. Another set of samples deformed under the same conditions were heat treated at 1173 K (900 °C) for an hour followed by water quench. Finite element modeling was used to provide the strains, strain rates, and temperature profiles of the hot compression samples, and the microstructure and texture evolution was examined at four positions on each sample, representative of different strain ranges. Lamellae fragmentation and kinking are the dominant microstructural features at lower strain range up to a maximum of 2.0, whereas globularization dominates at strains above 2.0 for the as-deformed samples. The globularization fraction generally increases with strain, or by post-deformation heat treatment, but fluctuates at lower strain. The grain size of the globular α is almost constant with strain and maximizes for samples with the lowest crosshead speed due to the longer deformation time. The globular α grain also coarsens because of post-deformation heat treatment, with its size increasing with strain level. With respect to texture evolution, a basal transverse ring and another component 30 deg from ND is determined for samples deformed at 12.5 mms, which is consistent with the temperature increase to close to β-transus from simulation results. The texture type remains unchanged with its intensity increased and spreads with increasing strain. [ABSTRACT FROM AUTHOR]

The dwell effects of Ti624 x ( x = 2 to 6) alloys, including dwell fatigue life debit, fracture mode and strain accumulation, were characterized and compared. With increasing Mo content, the dwell fatigue life debit decreases quickly, and dwell fatigue fracture exhibits a transition from subsurface to surface initiation. Accompanying these changes, the accumulated strain decreases, and the pattern of secondary cracks loses morphological features typical of dwell cracks. These variations in the fatigue behavior of Ti624 x were attributed on the fundamental level to the dual effects of Mo: It decreases the β transus of titanium and, as a slow diffuser, reduces the rate of phase transformation from β to α. A higher Mo content encourages nucleation of multiple variants of α laths and promotes the transition from aligned colonies to basketweave microstructure during cooling after β forging. As a result both the grain size and microtexture intensity of α grains in the two-phase processed and heat treated microstructure are reduced. Smaller grain size of the alloys with higher Mo content produces smaller slip band spacing and reduces accumulated strain during dwell fatigue, thus reducing propensity for crack initiation. Microtexture was shown to be the direct cause of dwell sensitivity, and their relationship was described with the aid of a two-region redistribution model based on a previous two-element redistribution model proposed by Bache. [ABSTRACT FROM AUTHOR]

Keywords: Passion fruit; Begomovirus; Euphorbia leaf curl virus; papaya leaf curl Guangdong virus EN Passion fruit Begomovirus Euphorbia leaf curl virus papaya leaf curl Guangdong virus 1367 1367 1 11/29/21 20211101 NES 211101 Supplementary Information The online version contains supplementary material available at https://doi.org/10.1007/s42161-021-00932-z. Passion fruit, Begomovirus, Euphorbia leaf curl virus, papaya leaf curl Guangdong virus Euphorbia leaf curl virus (EuLCV) and papaya leaf curl Guangdong virus (PaLCuGDV), which can cause obvious symptoms on passion fruit, were first reported in Asia (Cheng et al. [1], Kil et al. [3]). [Extracted from the article]