47 research outputs found

    High-Entropy Enhanced Negative Thermal Expansion Perfomance in Antiperovkites

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    The negative thermal expansion (NTE) materials, which can act as thermal-expansion compensators to counteract the positive thermal expansion, have great applications merit in precision engineering. However, the exploration of NTE behavior with a wide temperature range has reached its upper ceiling through traditional doping strategies due to composition limitations. The unique sluggish characteristic in phase transition and extended optimization space in recent high entropy systems has great potential to broaden the temperature range in electronic transitions-induced NTE materials. Mn-based anti-perovskites offer an ideal platform for the exploration of high entropy NTE material due to their abundant element selection and controllable NTE performance. In this paper, the high entropy strategy is first introduced to broaden the NTE temperature range by relaxing the abrupt phase transition in Mn-based anti-perovskite nitride. We propose an empirical screening method to synthesize the high-entropy anti-perovskite (HEAP). it is found that magnetic phase separation from anti-ferromagnetic CII to paramagnetic CI surviving in an ultra-wide temperature range of 5K<=T<=350K (Delta_T=345K), revealing a unique sluggish characteristic. Consequently, a remarkable NTE behavior (up to Delta_T=235K, 5K<=T<=240K) with a coefficient of thermal expansion of -4.7x10-6/K, has been obtained in HEAP. It is worth noting that the temperature range is two/three times wider than that of low-entropy systems. The sluggish characteristic has been further experimentally proved to come from disturbed phase transition dynamics due to distortion in atomic spacing and chemical environmental fluctuation observed by the spherical aberration-corrected electron microscope. Our demonstration provides a unique paradigm for broadening the temperature range of NTE materials induced by phase transition through entropy engineering.Comment: 34 page

    The complete mitochondrial genome of Downesia tarsata (Coleoptera: Chrysomelidae: Cassidinae)

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    Downesia species are leaf-mining beetles mainly feed on Poaceae plants in the tropical and subtropical areas in Asia. In this study, we firstly sequenced and reported the complete mitochondrial genome for the genus. The complete mitogenome of Downesia tarsata is 18,557 bp in length, including 13 protein-coding genes (PCG), 22 transfer RNA (tRNA), two ribosomal RNA (rRNA), and one AT-rich region. Phylogenomic analysis indicated that D. tarsata is closely related to Agonita chinensis, and the two species belong to the same tribe of Gonophorini. The complete mitochondrial genome of D. tarsata could help clarify the phylogenetic relationship among Cassidinae species

    Induced dopaminergic neurons: A new promise for Parkinson’s disease

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    Motor symptoms that define Parkinson’s disease (PD) are caused by the selective loss of nigral dopaminergic (DA) neurons. Cell replacement therapy for PD has been focused on midbrain DA neurons derived from human fetal mesencephalic tissue, human embryonic stem cells (hESC) or human induced pluripotent stem cells (iPSC). Recent development in the direct conversion of human fibroblasts to induced dopaminergic (iDA) neurons offers new opportunities for transplantation study and disease modeling in PD. The iDA neurons are generated directly from human fibroblasts in a short period of time, bypassing lengthy differentiation process from human pluripotent stem cells and the concern for potentially tumorigenic mitotic cells. They exhibit functional dopaminergic neurotransmission and relieve locomotor symptoms in animal models of Parkinson’s disease. In this review, we will discuss this recent development and its implications to Parkinson’s disease research and therapy. Keywords: Parkinson’s disease, Induced dopaminergic neuron, Induced neuron, Induced pluripotent stem cell, Transcription facto

    Green Fluorescent Protein (GFP)-Based Overexpression Screening and Characterization of AgrC, a Receptor Protein of Quorum Sensing in Staphylococcus aureus

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    Staphylococcus aureus AgrC is an important component of the agr quorum-sensing system. AgrC is a membrane-embedded histidine kinase that is thought to act as a sensor for the recognition of environmental signals and the transduction of signals into the cytoplasm. However, the difficulty of expressing and purifying functional membrane proteins has drastically hindered in-depth understanding of the molecular structures and physiological functions of these proteins. Here, we describe the high-yield expression and purification of AgrC, and analyze its kinase activity. A C-terminal green fluorescent protein (GFP) fusion to AgrC served as a reporter for monitoring protein expression levels in real time. Protein expression levels were analyzed by the microscopic assessment of the whole-cell fluorescence. The expressed AgrC-GFP protein with a C-terminal His-tagged was purified using immobilized metal affinity chromatography (IMAC) and size exclusion chromatography (SEC) at yields of ≥10 mg/L, following optimization. We also assessed the effects of different detergents on membrane solubilization and AgrC kinase activity, and polyoxyethylene-(23)-lauryl-ether (Brij-35) was identified as the most suitable detergent. Furthermore, the secondary structural stability of purified AgrC was analyzed using circular dichroism (CD) spectroscopy. This study may serve as a general guide for improving the yields of other membrane protein preparations and selecting the appropriate detergent to stabilize membrane proteins for biophysical and biochemical analyses

    Complete Mitogenome of a Leaf-Mining Buprestid Beetle, Trachys auricollis, and Its Phylogenetic Implications

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    A complete mitogenome of Trachys auricollis is reported, and a mitogenome-based phylogenetic tree of Elateriformia with all protein-coding genes (PCGs), rRNAs, and tRNAs is presented for the first time. The complete mitochondrial genome of T. auricollis is 16,429 bp in size and contains 13 PCGs, two rRNA genes, 22 tRNA genes, and an A + T-rich region. The A + T content of the entire genome is approximately 71.1%, and the AT skew and GC skew are 0.10 and &minus;0.20, respectively. According to the the nonsynonymous substitution rate to synonymous substitution rates (Ka/Ks) of all PCGs, the highest and lowest evolutionary rates were observed for atp8 and cox1, respectively, which is a common finding among animals. The start codons of all PCGs are the typical ATN. Ten PCGs have complete stop codons, but three have incomplete stop codons with T or TA. As calculated based on the relative synonymous codon usage (RSCU) values, UUA(L) is the codon with the highest frequency. Except for trnS1, all 22 tRNA genes exhibit typical cloverleaf structures. The A + T-rich region of T. auricollis is located between rrnS and the trnI-trnG-trnM gene cluster, with six 72-bp tandem repeats. Both maximum likelihood (ML) and Bayesian (BI) trees suggest that Buprestoidea is close to Byrrhoidea and that Buprestoidea and Byrrhoidea are sister groups of Elateroidea, but the position of Psephenidae is undetermined. The inclusion of tRNAs might help to resolve the phylogeny of Coleoptera

    Crystal structure and functional implications of the tandem-type universal stress protein UspE from Escherichia coli

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    This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Abstract Background The universal stress proteins (USP) family member UspE is a tandem-type USP that consists of two Usp domains. The UspE expression levels of the Escherichia coli (E. coli) become elevated in response to oxidative stress and DNA damaging agents, including exposure to mitomycin C, cadmium, and hydrogen peroxide. It has been shown that UspA family members are survival factors during cellular growth arrest. The structures and functions of the UspA family members control the growth of E. coli in animal hosts. While several UspA family members have known structures, the structure of E. coli UspE remains to be elucidated. Results To understand the biochemical function of UspE, we have determined the crystal structure of E. coli UspE at 3.2 Å resolution. The asymmetric unit contains two protomers related by a non-crystallographic symmetry, and each protomer contains two tandem Usp domains. The crystal structure shows that UspE is folded into a fan-shaped structure similar to that of the tandem-type Usp protein PMI1202 from Proteus mirabilis, and it has a hydrophobic cavity that binds its ligand. Structural analysis revealed that E. coli UspE has two metal ion binding sites, and isothermal titration calorimetry suggested the presence of two Cd2+ binding sites with a Kd value of 38.3–242.7 μM. Structural analysis suggested that E. coli UspE has two Cd2+ binding sites (Site I: His117, His 119; Site II: His193, His244). Conclusion The results show that the UspE structure has a hydrophobic pocket. This pocket is strongly bound to an unidentified ligand. Combined with a previous study, the ligand is probably related to an intermediate in lipid A biosynthesis. Subsequently, sequence analysis found that UspE has an ATP binding motif (Gly269- X2-Gly272-X9-Gly282-Asn) in its C-terminal domain, which was confirmed by in vitro ATPase activity monitored using Kinase-Glo® Luminescent Kinase Assay. However, the residues constituting this motif were disordered in the crystal structure, reflecting their intrinsic flexibility. ITC experiments revealed that the UspE probably has two Cd2+ binding sites. The His117, His 119, His193, and His244 residues within the β-barrel domain are necessary for Cd2+ binding to UspE protein. As mentioned above, USPs are associated with several functions, such as cadmium binding, ATPase function, and involvement in lipid A biosynthesis by some unknown way

    Optical Properties of Yttria-Stabilized Zirconia Single-Crystals Doped with Terbium Oxide

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    A series of yttria-stabilized zirconia single-crystals doped with 0.000–0.250 mol% Tb4O7 was prepared by the optical floating-zone method. As shown by XRD and Raman spectroscopy, all of the crystals had a cubic-phase structure. These were initially orange–yellow in color, which is indicative of the presence of Tb4+ ions, but they then became colorless after being annealed in a H2/Ar atmosphere as a result of the reduction of Tb4+ to Tb3+. The absorption spectra of the unannealed samples show both the 4f 8→4f 75d1 transition of Tb3+ ions and the Tb4+ charge-transfer band. In addition, the transmittance of the crystals was increased by annealing. Under irradiation with 300 nm of light, all of the single-crystal samples showed seven emission peaks in the visible region, corresponding to the decay from the 5D3,4 excited state of Tb3+ to the 7FJ (J = 6–0) states. The most intense emission was at 544 nm, which corresponds to the typical strong green emission from the 5D4→7F5 transition in Tb3+ ions

    The genetic variation of SORCS1 is associated with late-onset Alzheimer's disease in Chinese Han population.

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    The variations of SORCS1 gene may play potential key roles in late-onset Alzheimer's disease (LOAD). To evaluate the relationship between the polymorphism of SORCS1 gene and LOAD in the ethnic Han Chinese, we conducted a case-control study to investigate the association between the single-nucleotide polymorphisms (SNPs) in intron 1 of SORCS1 and LOAD in Chinese Han population. Six reported SNPs in intron 1 of SORCS1 were analyzed by Snapshot, genotyping and haplotyping in 236 Chinese LOAD cases and 233 matched controls. The significant differences in frequencies of two SNPs (rs10884402, rs950809) were found between the two groups. In addition, haplotype analyses revealed that, in the LOAD group, the frequency of haplotypes C-C-G-T-C (alleles in order of rs17277986, rs6584777, rs10884402, rs7078098, rs950809 polymorphisms) were significantly higher (Psim<0.0001) while haplotype C-C-A-T-C, C-C-A-C-C, T-T-A-C-C were significantly lower (Psim<0.0001). Our data suggested that the genetic variation of the rs10884402 and rs950809 in intron 1 of SORCS1 was associated with the late-onset AD in the Chinese Han population

    Data_Sheet_1_Determining the nutritional values of new corn varieties on pigs and broilers.docx

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    The objective of this study was to evaluate the nutritional values of three new corn varieties (high-iron corn, cadmium-resistant corn, low-phytate phosphorus corn) cultivated with molecular marker-assisted selection breeding technique fed to growing pigs and broilers. Exp. 1 was conducted to compare the nutritional values of high-iron corn, high-chromium corn, low-phytate phosphorus corn and conventional corn fed to growing pigs based on a 15 × 2 Youden square design. Exp.2 was conducted to compare the nutritional values of high-iron corn, low-phytate phosphorus corn and conventional corn fed to broilers based on a completely randomized design. Parameters including nutrient digestibility, available energy and amino acids, and mineral deposition were measured. The results shows that the iron content in the high-iron corn and the cadmium content in the cadmium-resistant corn were 29.608 mg/kg and 0.0057 mg/kg, respectively, both were greater than those in the other three kinds of corns. When fed to growing pigs, the neutral detergent fiber digestibility of the high-iron corn group was lower than that of the conventional corn group (p < 0.05), and the acid detergent fiber digestibility of the high-iron group and the low-phytate phosphorus corn group was lower than that of the conventional corn group (p < 0.01). In addition, the digestible energy value of the high-iron corn in growing pigs was lower than that of the conventional corn (p < 0.05). When fed to broilers, it was observed that the tibia length of the low-phytate phosphorus corn group and the high-iron corn group was lower than that of the conventional corn group (p < 0.05). Moreover, the iron emission in feces of broilers fed the low-phytate phosphorus corn was lower than those fed the conventional corn and the high-iron corn (p < 0.05). In conclusion, modern breeding techniques could provide new plant ingredients which have potential benefits to pig and broiler production, but the comprehensive effects may be better when applied to growing pigs considering growth performance and environment effects. The breeding techniques related to the current study rarely changed the available energy values of the corn in growing pigs and broilers.</p
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