Organic donor–acceptor (DA) complexes have attracted wide attention in recent decades, resulting in the rapid development of organic binary system electronics. The design and synthesis of organic DA ...complexes with a variety of component structures have mainly focused on metallicity (or even superconductivity), emission, or ferroelectricity studies. Further efforts have been made in high-performance electronic investigations. The chemical versatility of organic semiconductors provides DA complexes with a great number of possibilities for semiconducting applications. Organic DA complexes extend the semiconductor family and promote charge separation and transport in organic field-effect transistors (OFETs) and organic photovoltaics (OPVs). In OFETs, the organic complex serves as an active layer across extraordinary charge pathways, ensuring the efficient transport of induced charges. Although an increasing number of organic semiconductors have been reported to exhibit good p- or n-type properties (mobilities higher than 1 or even 10 cm2 V–1 s–1), critical scientific challenges remain in utilizing the advantages of existing semiconductor materials for more and wider applications while maintaining less complicated synthetic or device fabrication processes. DA complex materials have revealed new insight: their unique molecular packing and structure–property relationships. The combination of donors and acceptors could offer practical advantages compared with their unimolecular materials. First, growing crystals of DA complexes with densely packed structures will reduce impurities and traps from the self-assembly process. Second, complexes based on the original structural components could form superior mixture stacking, which can facilitate charge transport depending on the driving force in the coassembly process. Third, the effective use of organic semiconductors can lead to tunable band structures, allowing the operation mode (p- or n-type) of the transistor to be systematically controlled by changing the components. Finally, theoretical calculations based on cocrystals with unique stacking could widen our understanding of structure–property relationships and in turn help us design high-performance semiconductors based on DA complexes. In this Account, we focus on discussing organic DA complexes as a new class of semiconducting materials, including their design, growth methods, packing modes, charge-transport properties, and structure–property relationships. We have also fabricated and investigated devices based on these binary crystals. This interdisciplinary work combines techniques from the fields of self-assembly, crystallography, condensed-matter physics, and theoretical chemistry. Researchers have designed new complex systems, including donor and acceptor compounds that self-assemble in feasible ways into highly ordered cocrystals. We demonstrate that using this crystallization method can easily realize ambipolar or unipolar transport. To further improve device performance, we propose several design strategies, such as using new kinds of donors and acceptors, modulating the energy alignment of the donor (ionization potential, IP) and acceptor (electron affinity, EA) components, and extending the π-conjugated backbones. In addition, we have found that when we use molecular “doping” (2:1 cocrystallization), the charge-transport nature of organic semiconductors can be switched from hole-transport-dominated to electron-transport-dominated. We expect that the formation of cocrystals through the complexation of organic donor and acceptor species will serve as a new strategy to develop semiconductors for organic electronics with superior performances over their corresponding individual components.
Abstract
We study the collimation and acceleration of jets in the nearby giant radio galaxy NGC 315, using multifrequency Very Long Baseline Array observations and archival High Sensitivity Array and ...Very Large Array data. We find that the jet geometry transitions from a semi-parabolic shape into a conical/hyperbolic shape at a distance of ≈10
5
gravitational radii. We constrain the frequency-dependent position of the core, from which we locate the jet base. The jet collimation profile in the parabolic region is in good agreement with the steady axisymmetric force-free electrodynamic solution for the outermost poloidal magnetic field line anchored to the black hole event horizon on the equatorial plane, similar to the nearby radio galaxies M87 and NGC 6251. The velocity field derived from the asymmetry in brightness between the jet and counterjet shows gradual acceleration up to the bulk Lorentz factor of Γ ∼ 3 in the region where the jet collimation occurs, confirming the presence of the jet acceleration and collimation zone. These results suggest that the jets are collimated by the pressure of the surrounding medium and accelerated by converting Poynting flux to kinetic energy flux. We discover limb brightening of the jet in a limited distance range where the angular resolution of our data is sufficient to resolve the jet transverse structure. This indicates that either the jet has a stratified velocity field of fast-inner and slow-outer layers or the particle acceleration process is more efficient in the outer layer owing to the interaction with the surroundings on parsec scales.
Integrating electronics and photonics is critically important for the realization of high-density and high-speed optoelectronic circuits. However, it remains challenging to achieve this target due to ...the difficulty of merging many different areas of science and technology. Here, we show an organic integrated optoelectronic device, namely, organic field-effect optical waveguide, integrating field-effect transistor and optical waveguide together. In such device, the propagation of optical waveguide in the active organic semiconductor can be tuned by the third terminal-the gate electrode of transistor, giving a controllable modulation depth as high as 70% and 50% in parallel and perpendicular directions of charge transport versus optical waveguide, respectively. Also, the optical waveguide with different directions can turn the field-effect of the device with the photodependence ratio up to 14800. The successful integration of active field-effect transistor with semiconductor waveguide modulator expands opportunities for creating scalable integration of electronics and photonics in a chip.
Environmental stresses such as drought, salinity, and cold are major factors that significantly limit agricultural productivity. NAC transcription factors play essential roles in response to various ...abiotic stresses. However, the paucity of wheat NAC members functionally characterized to date does not match the importance of this plant as a world staple crop. Here, the function of TaNAC2 was characterized in Arabidopsis thaliana. A fragment of TaNAC2 was obtained from suppression subtractive cDNA libraries of wheat treated with polyethylene glycol, and its full-length cDNA was obtained by searching a full-length wheat cDNA library. Gene expression profiles indicated that TaNAC2 was involved in response to drought, salt, cold, and abscisic acid treatment. To test its function, transgenic Arabidopsis lines overexpressing TaNAC2-GFP controlled by the cauliflower mosaic virus 35S promoter were generated. Overexpression of TaNAC2 resulted in enhanced tolerances to drought, salt, and freezing stresses in Arabidopsis, which were simultaneously demonstrated by enhanced expression of abiotic stress-response genes and several physiological indices. Therefore, TaNAC2 has potential for utilization in transgenic breeding to improve abiotic stress tolerances in crops.
Rapid advances in next-generation sequencing methods have provided new opportunities for transcriptome sequencing (RNA-Seq). The unprecedented sequencing depth provided by RNA-Seq makes it a powerful ...and cost-efficient method for transcriptome study, and it has been widely used in model organisms and non-model organisms to identify and quantify RNA. For non-model organisms lacking well-defined genomes, de novo assembly is typically required for downstream RNA-Seq analyses, including SNP discovery and identification of genes differentially expressed by phenotypes. Although RNA-Seq has been successfully used to sequence many non-model organisms, the results of de novo assembly from short reads can still be improved by using recent bioinformatic developments.
In this study, we used 212.6 million pair-end reads, which accounted for 16.2 Gb, to assemble the hexaploid wheat transcriptome. Two state-of-the-art assemblers, Trinity and Trans-ABySS, which use the single and multiple k-mer methods, respectively, were used, and the whole de novo assembly process was divided into the following four steps: pre-assembly, merging different samples, removal of redundancy and scaffolding. We documented every detail of these steps and how these steps influenced assembly performance to gain insight into transcriptome assembly from short reads. After optimization, the assembled transcripts were comparable to Sanger-derived ESTs in terms of both continuity and accuracy. We also provided considerable new wheat transcript data to the community.
It is feasible to assemble the hexaploid wheat transcriptome from short reads. Special attention should be paid to dealing with multiple samples to balance the spectrum of expression levels and redundancy. To obtain an accurate overview of RNA profiling, removal of redundancy may be crucial in de novo assembly.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Dual loop ORC system is designed to recover waste heat from a diesel engine.•R245fa is used as working fluid for the dual loop ORC system.•Waste heat characteristic under engine various operating ...conditions is analyzed.•Performance of the combined system under various operating conditions is studied.•The waste heat from coolant and intake air has considerable potential for recovery.
To take full advantage of the waste heat from a diesel engine, a set of dual loop organic Rankine cycle (ORC) system is designed to recover exhaust energy, waste heat from the coolant system, and released heat from turbocharged air in the intercooler of a six-cylinder diesel engine. The dual loop ORC system consists of a high temperature loop ORC system and a low temperature loop ORC system. R245fa is selected as the working fluid for both loops. Through the engine test, based on the first and second laws of thermodynamics, the performance of the dual loop ORC system for waste heat recovery is discussed based on the analysis of its waste heat characteristics under engine various operating conditions. Subsequently, the diesel engine-dual loop ORC combined system is presented, and the effective thermal efficiency and the brake specific fuel consumption (BSFC) are chosen to evaluate the operating performances of the diesel engine-dual loop ORC combined system. The results show that, the maximum waste heat recovery efficiency (WHRE) of the dual loop ORC system can reach 5.4% under engine various operating conditions. At the engine rated condition, the dual loop ORC system achieves the largest net power output at 27.85kW. Compared with the diesel engine, the thermal efficiency of the combined system can be increased by 13%. When the diesel engine is operating at the high load region, the BSFC can be reduced by a maximum 4%.
Polyploidization and introgression are major events driving plant genome evolution and influencing crop breeding. However, the mechanisms underlying the higher-order chromatin organization of ...subgenomes and alien chromosomes are largely unknown.
We probe the three-dimensional chromatin architecture of Aikang 58 (AK58), a widely cultivated allohexaploid wheat variety in China carrying the 1RS/1BL translocation chromosome. The regions involved in inter-chromosomal interactions, both within and between subgenomes, have highly similar sequences. Subgenome-specific territories tend to be connected by subgenome-dominant homologous transposable elements (TEs). The alien 1RS chromosomal arm, which was introgressed from rye and differs from its wheat counterpart, has relatively few inter-chromosome interactions with wheat chromosomes. An analysis of local chromatin structures reveals topologically associating domain (TAD)-like regions covering 52% of the AK58 genome, the boundaries of which are enriched with active genes, zinc-finger factor-binding motifs, CHH methylation, and 24-nt small RNAs. The chromatin loops are mostly localized around TAD boundaries, and the number of gene loops is positively associated with gene activity.
The present study reveals the impact of the genetic sequence context on the higher-order chromatin structure and subgenome stability in hexaploid wheat. Specifically, we characterized the sequence homology-mediated inter-chromosome interactions and the non-canonical role of subgenome-biased TEs. Our findings may have profound implications for future investigations of the interplay between genetic sequences and higher-order structures and their consequences on polyploid genome evolution and introgression-based breeding of crop plants.
The proteins of the MYB superfamily play central roles in developmental processes and defence responses in plants. Sixty unique wheat MYB genes that contain full-length cDNA sequences were isolated. ...These 60 genes were grouped into three categories, namely one R1R2R3-MYB, 22 R2R3-MYBs, and 37 MYB-related members. The sequence composition of the R2 and R3 repeats was conserved among the 22 wheat R2R3-MYB proteins. Phylogenetic comparison of the members of this superfamily among wheat, rice, andArabidopsisrevealed that the putative functions of some wheat MYB proteins were clustered into theArabidopsisfunctional clades. Tissue-specific expression profiles showed that most of the wheat MYB genes were expressed in all of the tissues examined, suggesting that wheat MYB genes take part in multiple cellular processes. The expression analysis during abiotic stress identified a group of MYB genes that respond to one or more stress treatments. The overexpression of a salt-inducible gene,TaMYB32, enhanced the tolerance to salt stress in transgenicArabidopsis. This study is the first comprehensive study of the MYB gene family in Triticeae.
The MYB-type proteins are involved in various processes of plant growth, development, and stress response. In a previous work, a polyethylene glycol (PEG) stress-induced gene, TaMYB30, which encodes ...a R2R3-type MYB protein was identified in wheat. In this study, the isolation and functional characterization of the TaMYB30 gene are reported. Three homologous sequences of TaMYB30 were isolated from hexaploid wheat and designated as TaMYB30-A, TaMYB30-B, and TaMYB30-D genes based on the localizations of these three sequences to chromosomes 2A, 2B, and 2D, respectively. The expression levels of these three genes were similar under PEG stress conditions, and TaMYB30-B was selected for further analysis. The TaMYB30-B protein was localized to the nucleus where it activated transcription. The detailed characterization of Arabidopsis transgenic plants that overexpress the TaMYB30-B gene revealed that the TaMYB30-B protein can improve drought stress tolerance during the germination and the seedling stages. It was also found that overexpression of TaMYB30-B resulted in altered expression levels of some drought stress-responsive genes and changes in several physiological indices, which allow plants to overcome adverse conditions. These results indicate that the TaMYB30-B protein plays important roles in plant stress tolerance, and modification of its expression may improve drought stress tolerance in crop plants.
Abstract
Continuous monitoring of arterial blood pressure (BP) outside of a clinical setting is crucial for preventing and diagnosing hypertension related diseases. However, current continuous BP ...monitoring instruments suffer from either bulky systems or poor user-device interfacial performance, hampering their applications in continuous BP monitoring. Here, we report a thin, soft, miniaturized system (TSMS) that combines a conformal piezoelectric sensor array, an active pressure adaptation unit, a signal processing module, and an advanced machine learning method, to allow real wearable, continuous wireless monitoring of ambulatory artery BP. By optimizing the materials selection, control/sampling strategy, and system integration, the TSMS exhibits improved interfacial performance while maintaining Grade A level measurement accuracy. Initial trials on 87 volunteers and clinical tracking of two hypertension individuals prove the capability of the TSMS as a reliable BP measurement product, and its feasibility and practical usability in precise BP control and personalized diagnosis schemes development.
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