Friction stir welding FSW） has achieved remarkable success in the joining and processing of aluminium alloys and other softer structural alloys. Conventional FSW, however, has not been entirely ...successful in the joining, processing and manufacturing of different desired materials essential to meet the sophis- ticated green globe requirements. Through the efforts of improving the process and transferring the existing friction stir knowledge base to other advanced applications, several friction stir based daughter technologies have emerged over the timeline, A few among these technologies are well developed while others are under the process of emergence. Beginning with a broad classification of the scattered fric- tions stir based technologies into two categories, welding and processing, it appears now time to know, compile and review these to enable their rapid access for reference and academia. In this review article, the friction stir based technologies classified under the categol~J of welding are those applied for join- ing of materials while the remnant are labeled as friction stir processing （FSP） technologies. This review article presents an overview of four general aspects of both the developed and the developing friction stir based technologies, their associated process parameters, metallurgical features of their products and their feasibility and application to various materials. The lesser known and emerging technologies have been emphasized.
Here, deep sequencing results of the maize transcriptome in leaves and roots were compared under high‐nitrogen (HN) and low‐nitrogen (LN) conditions to identify differentially expressed circRNAs ...(DECs).
Circular RNAs (circRNAs) are covalently closed non‐coding RNA with widely regulatory potency that has been identified in animals and plants. However, the understanding of circRNAs involved in responsive nitrogen deficiency remains to be elucidated.
A total of 24 and 22 DECs were obtained from the leaves and roots, respectively. Ten circRNAs were validated by divergent and convergent primers, and 6 DECs showed the same expression tendency validated by reverse transcriptase‐quantitative PCR. Integrating the identified differentially expressed miRNAs, 34 circRNAs could act as miRNA decoys, which might play important roles in multiple biological processes, including organonitrogen compound biosynthesis and regulation of the metabolic process. A total of 51 circRNA‐parent genes located in the genome‐wide association study identified loci were assessed between HN and LN conditions and were associated with root growth and development.
In summary, our results provide valuable information regarding further study of maize circRNAs under nitrogen deficiency and provide new insights into screening of candidate genes as well as the improvement of maize regarding nitrogen deficiency resistance. CircRNA–miRNA–mRNA co‐expression networks were constructed to explore the circRNAs that participated in biological development and nitrogen metabolism.
The LN‐responsive circRNAs provide new insights into screening of candidate genes as well as the improvement of maize regarding nitrogen deficiency resistance.
Electric vehicle development is critical to achieve the sustainable goals, while the hit of COVID-19 strikes the market and brings challenges to the whole industry. China, among one of the earliest ...regions affected by COVID-19 and takes a great part in the global electric vehicle market, is attracting growing attention on its post-pandemic trends in the electric vehicle industry. This paper provides a comprehensive analysis of COVID-19 impacts on China's electric vehicle industry from both the demand side and the supply side. Both challenges and opportunities for China's electric vehicle development are revealed with emerging trend analysis. It is found that the COVID-19 outbreak has reduced electric vehicle sales in the short-term, but may also stimulate future electric vehicle demand especially for large electric cars with better performance. Meanwhile, travel restrictions caused by COVID-19 have interrupted electric vehicle material supplies that relying on imports, accelerating domestic substitute exploitation and inventory improvement for critical parts. Additionally, massive lockdowns for controlling COVID-19 have disrupted productions and operations, which tends to expel small brands out of the competitive market, concentrating China's electric vehicle industry to the leading brands. Finally, the social distancing trend after pandemic is bringing challenges to traditional EV distribution channels with dealers, pushing automakers to develop innovative online selling channels. These impacts are likely to lead to a reformation of China's electric vehicle industry towards a more advanced and reliable future.
•Impacts of COVID-19 on China's EV market and supply chain are analyzed.•COVID-19 outbreak may shift consumer demand to large EVs with better performance.•Supply interruption by travel restrictions may promote domestic R&D and reserves.•Suspension caused by lockdown may expel SMEs and concentrate China's EV industry.•Post-pandemic social distancing may lead to innovative online EV selling models.
This review article attempts to provide a comprehensive review of the recent progress in the so-called resistive random access memories (RRAMs). First, a brief introduction is presented to describe ...the construction and development of RRAMs, their potential for broad applications in the fields of nonvolatile memory, unconventional computing and logic devices, and the focus of research concerning RRAMs over the past decade. Second, both inorganic and organic materials used in RRAMs are summarized, and their respective advantages and shortcomings are discussed. Third, the important switching mechanisms are discussed in depth and are classified into ion migration, charge trapping/de-trapping, thermochemical reaction, exclusive mechanisms in inorganics, and exclusive mechanisms in organics. Fourth, attention is given to the application of RRAMs for data storage, including their current performance, methods for performance enhancement, sneak-path issue and possible solutions, and demonstrations of 2-D and 3-D crossbar arrays. Fifth, prospective applications of RRAMs in unconventional computing, as well as logic devices and multi-functionalization of RRAMs, are comprehensively summarized and thoroughly discussed. The present review article ends with a short discussion concerning the challenges and future prospects of the RRAMs.
We present the first finding of continental crust-derived Precambrian zircons in garnet/spinel pyroxenite veins within mantle xenoliths carried by the Neogene Hannuoba basalt in the central zone of ...the North China Craton (NCC). Petrological and geochemical features indicate that these mantle-derived composite xenoliths were formed by silicic melt–lherzolite interaction. The Precambrian zircon ages can be classified into three age groups of 2·4–2·5 Ga, 1·6–2·2 Ga and 0·6–1·2 Ga, coinciding with major geological events in the NCC. These Precambrian zircons fall in the field of continental granitoid rocks in plots of U/Yb vs Hf and Y. Their igneous-type REE patterns and metamorphic zircon type CL images indicate that they were not crystallized during melt–peridotite interaction and subsequent high-pressure metamorphism. The ∼2·5 Ga zircons have positive εHf(t) values (2·9–10·6), whereas the younger Precambrian zircons are dominated by negative εHf(t) values, indicating an ancient continental crustal origin. These observations suggest that the Precambrian zircons were xenocrysts that survived melting of recycled continental crustal rocks and were then injected with silicate melt into the host peridotite. In addition to the Precambrian zircons, igneous zircons of 315 ± 3 Ma (2σ), 80–170 Ma and 48–64 Ma were separated from the garnet/spinel pyroxenite veins; these provide evidence for lower continental crust and oceanic crust recycling-induced multi-episodic melt–peridotite interactions in the central zone of the NCC. The combination of the positive εHf(t) values (2·91–24·6) of the 315 Ma zircons with the rare occurrence of 302–324 Ma subduction-related diorite–granite plutons in the northern margin of the NCC implies that the 315 Ma igneous zircons might record melt–peridotite interactions in the lithospheric mantle induced by Palaeo-Asian oceanic crust subduction. Igneous zircons of age 80–170 Ma generally coexist with the Precambrian metamorphic zircons and have lower Ce/Yb and Th/U ratios, higher U/Yb ratios and greater negative Eu anomalies. The εHf(t) values of these zircons vary greatly from –47·6 to 24·6. The 170–110 Ma zircons are generally characterized by negative εHf(t) values, whereas the 110–100 Ma zircons have positive εHf(t) values. These observations suggest that melt–peridotite interactions at 80–170 Ma were induced by partial melting of recycled continental crust. The 48–64 Ma igneous zircons are characterized by negligible Ce anomalies, unusually high REE, U and Th contents, and positive εHf(t) values. These features imply that the melt–peridotite interactions at 48–64 Ma could be associated with a depleted mantle-derived carbonate melt or fluid.
Aims
Multi‐species biofilms formed by fungi and bacteria are clinically common and confer the commensal micro‐organisms with protection against antimicrobial therapies. Previously, the plant alkaloid ...berberine was reported to show antimicrobial efficacy to eliminate bacterial and fungal biofilms. In this study, the combination of berberine and amphotericin B, an antifungal agent, was evaluated against dual‐species Candida albicans/Staphylococcus aureus biofilms.
Methods and Results
Combinatorial treatment by berberine and amphotericin B significantly reduced the biomass and viability of residing species in biofilms. Moreover, morphological examination revealed hyphal filamentation of C. albicans and coadhesion between C. albicans/S. aureus were considerably impaired by the treatment. These effects coincided with the reduced expression of cell surface components and quorum‐sensing‐related genes in both C. albicans and S. aureus. Additionally, in C. albicans, the core transcription factors for controlling biofilm formation together with a crucial component of dual‐species biofilms were also downregulated.
Conclusions
These results demonstrated synergistic effects of berberine and amphotericin B against C. albicans/S. aureus dual‐species biofilms.
Significance and Impact of the Study
This study confirms the potential of berberine and amphotericin B for treating the C. albicans/S. aureus biofilms related infections and reveals molecular basis for the efficacy of combinatorial treatment.
Abstract
Constrained by the Nielsen-Ninomiya no-go theorem, in all so-far experimentally determined Weyl semimetals (WSMs) the Weyl points (WPs) always appear in pairs in the momentum space with no ...exception. As a consequence, Fermi arcs occur on surfaces which connect the projections of the WPs with opposite chiral charges. However, this situation can be circumvented in the case of unpaired WP, without relevant surface Fermi arc connecting its surface projection, appearing singularly, while its Berry curvature field is absorbed by nontrivial charged nodal walls. Here, combining angle-resolved photoemission spectroscopy with density functional theory calculations, we show experimentally that a singular Weyl point emerges in PtGa at the center of the Brillouin zone (BZ), which is surrounded by closed Weyl nodal walls located at the BZ boundaries and there is no Fermi arc connecting its surface projection. Our results reveal that nontrivial band crossings of different dimensionalities can emerge concomitantly in condensed matter, while their coexistence ensures the net topological charge of different dimensional topological objects to be zero. Our observation extends the applicable range of the original Nielsen-Ninomiya no-go theorem which was derived from zero dimensional paired WPs with opposite chirality.
Gao reads with great interest the article by Puri et at. They provided important evidence that adults with self-reported limitations of physical function (PF) had significantly higher odds of having ...a doctor diagnosed sleep disorder (SD) compared with those without PF limitation. They also found that 'participants having cognitive problems and cardiovascular and pulmonary disorders as secondary conditions that cause difficulty in PF have 145% and 28% higher odds of having a SD". When defining 'cognitive problems', the authors only considered depression, anxiety, and emotional problems, whereas they failed to take other important neurocognitive issues into account especially cognitive impairment. As the study participants were primarily middle-aged and older adults with a mean age close to 60 years, those with mild or even more severe cognitive impairment might have misreported their physical functioning status and history of SD.
Abstract There are indications for changes in glutamate metabolism in relation to depression or suicide. The glutamate-glutamine cycle and neuronal/glial glutamate transporters mediate the uptake of ...the glutamate and glutamine. The expression of various components of the glutamate-glutamine cycle and the neuronal/glial glutamate transporters was determined by qPCR in postmortem prefrontal cortex. The anterior cingulate cortex (ACC) and the dorsolateral prefrontal cortex (DLPFC) were selected from young MDD patients who had committed suicide (MDD-S; n = 17), from MDD patients who died of non-suicide related causes (MDD-NS; n = 7) and from matched control subjects (n = 12). We also compared elderly depressed patients who had not committed suicide (n = 14) with matched control subjects (n = 22). We found that neuronal located components (EAAT3, EAAT4, ASCT1, SNAT1, SNAT2) of the glutamate-glutamine cycle were increased in the ACC while the astroglia located components (EAAT1, EAAT2, GLUL) were decreased in the DLPFC of MDD-S patients. In contrast, most of the components in the cycle were increased in the DLPFC of MDD-NS patients. In conclusion, the glutamate-glutamine cycle - and thus glutamine transmission - is differentially affected in depressed suicide patients and depressed non-suicide patients in an area specific way.
•Nanostructure of spun-on and spray-on PEDOT:PSS thin films is studied.•A correlation is established between the film nanostructure and electrical conductivity.•Effect of process parameters is ...studied on the film characteristics.•A high solution concentration, high process temperature and multiple deposition layers are recommended.
The goal of this paper is to study the characteristics of PEDOT:PSS thin films and the effects of varying the processing parameters on the structure, functionality, and surface wetting of spun-on and spray-on PEDOT:PSS thin films. PEDOT:PSS is a polymer mixture, which is electrically conductive and transparent and, therefore, is an attractive material for some optoelectronic applications, such as organic and perovskite solar cells. In this work, the films are fabricated using spin coating (a lab-scale method) and spray coating (an up-scalable method). The effects of spinning speed, drying time, and post-annealing temperature on spun-on samples and the effects of the substrate temperature and number of spray passes (deposition layers) on spray-on samples, as well as the effect of precursor solution concentration on both cases are investigated. Various characterization tools, such as AFM, SEM, XRD, confocal laser scanning microscopy (CLSM), and electrical conductivity measurements are used to determine the film roughness, thickness, structure, and morphology. The solution precursor physical data, such as contact angle on glass substrates, viscosity, and interfacial tension, are also obtained within a practical range of temperatures and concentrations. It is found that in both spin and spray coating routes, only well-controlled operating conditions result in the formation of conductive and defect-free PEDOT:PSS films. The formation of PEDOT:PSS thin films with small grains composed of PEDOT forming the core of the grains and PSS forming a shell or coating, which are evenly distributed in a PSS-rich matrix, is favored. Conditions leading to the above-mentioned electrically conductive scenario are identified. Other topics, such as the formation of defects and dewetting, are also elucidated.
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