During meiosis, homologous chromosomes undergo a dramatic movement in order to correctly align. This is a critical meiotic event but the molecular properties of this 'chromosomal dance' still remainunclear. We...
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During meiosis, homologous chromosomes undergo a dramatic movement in order to correctly align. This is a critical meiotic event but the molecular properties of this 'chromosomal dance' still remainunclear. We identified DEB-1 - an orthologue of mammalian vinculin - as a new component of the mechanistic modules responsible for attaching the chromosomes to the nuclear envelope as apart of the LINccomplex. In early meiotic nuclei of c. elegans, DEB-1 is localized to the nuclear periphery and alongside the synaptonemal complex of paired homologues. Upon DEB-1 depletion, chromosomes attached to SUN-1 foci remain highly motile until late pachytene. Although the initiation of homologue pairing started normally, irregularities in the formation of the synaptonemal complex occur, and these results in meiotic defects such as increased number of univalents at diakinesis and high embryonic lethality. Our data identify DEB-1 as a new player regulating chromosome dynamics and pairing during meiotic prophase I.
carbon material doped with nitrogen and transition metal is a kind of promising candidate of the platinum for oxygen reduction reaction (ORR) process due to its low cost, efficiency and stability. Here we demonstrate ...
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carbon material doped with nitrogen and transition metal is a kind of promising candidate of the platinum for oxygen reduction reaction (ORR) process due to its low cost, efficiency and stability. Here we demonstrate an original type of Fe/N/ccatalyst based on pore-in-pore structures (P-P Fe/N/c), showing one of the highest oxygen reduction reaction performances among all reported Fe/N/c-type catalysts (onset potential of 0.995 V, half-wave potential of 0.881 V vs. RHE with a relatively low mass loading of 0.32 mg cm(-2) and long-term durability (97% relative current in 60 000 s operation) in alkaline media. Such outstanding performances can be ascribed to the efficient active sites activated by the encapsulated atomic and subnanoscale iron, and great exposure of these active sites due to the unique pore-in-pore hierarchical construction. Once assembled in lithium-O-2 batteries, a specificcapacity of 7250 mA h g(-1) at 70 mA g(-1) can be obtained by the P-P Fe/N/ccatalyst. Moreover, upon cycling, the P-P Fe/N/c electrode can be cycled 150 times with no capacity loss, which is much longer than six cycles of pure Super P air electrode. These results evidently reveal the developed Fe/N/ccatalyst holds great promise to serve as an alternative to the conventional Pt-based noble metal catalysts.
Shwachman-Diamond syndrome is a rare autosomal recessive disorder (SDS;OMIM #260400) mainly characterized by bone marrow failure, exocrine pancreatic insufficiency, and skeletal defects. The first causative gene is SB...
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Shwachman-Diamond syndrome is a rare autosomal recessive disorder (SDS;OMIM #260400) mainly characterized by bone marrow failure, exocrine pancreatic insufficiency, and skeletal defects. The first causative gene is SBDS, identified in 2003, and patients clinically affected by SDS carry mainly SBDS mutations, and most of them are represented by common pathogenic variants derived from geneticconversion events between SBDS and its pseudogene, SBDSP1. The Italian Registry of SDS collected the index cases who received a clinical SDS diagnosis with the demonstration of SBDS biallelic mutations;one of these is always represented by the [c.258+2T>c], while the second one includes either the [c.183_184delinsTA>cT] or [c.183_184delinsTA>cT+c.258+2T>c] or [c.258+2T>c] in, respectively, 59, 12.5 and 10.83% of cases entered until May 2022. In the 17,67% the SBDS genotype is completed by fourteen different types of rare, private, pathogenic variants and all these alleles were observed once among Italian cases, except for [c.187G>T] and [c.258+533_459+403del] alleles, which were observed in two and four unrelated families, respectively. The first one is present in two families, both originating from Northern Tuscany, while for the second allele, the deletion, three families originate from Sicily and one from Lazio. The presence of the deletion in four families (corresponding to 3.31% of index cases), pushed us to investigate if it could be due to a founder effect, with the same mutation originating from a single ancestral event in all cases. Genotyping the region surrounding the SBDS locus, we defined a common haplotype in the families coming from Sicily, while a completely different one resulted in the family originated from Lazio. This result, identifying the most likely ancestral haplotype associated with the deletion of exon 3, suggested a potential founder effect that might be localized in the provinces of Palermo and Messina, in the middle of the North of Sicily. Our result
In this paper, a significant enhancement in current efficiency of the green tandem organic light-emitting diodes(TOLEDs) is demonstrated, which is based on a buffer-modified charge generation layer(cGL) of fullerene c...
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In this paper, a significant enhancement in current efficiency of the green tandem organic light-emitting diodes(TOLEDs) is demonstrated, which is based on a buffer-modified charge generation layer(cGL) of fullerene carbon(c60)/zinc-phthalocyanine(ZnPc). Al and MoO3 were used as the buffer-modified layers on both sides of the bilayer c60/ZnPc, respectively. Experimental results show that the inserted Al and MoO3 layers can effectively increase the electron extraction of the cGL for obtaining the device performance enhancement. compared with that of the green TOLEDs without buffer-modified layers in cGL(37.3 cd·A-1), the current efficiency of the green TOLEDs is increased to 54.1 cd·A-1. Further study results find that the performance can also be improved by optimizing the thickness of Al in the cGL. The maximum current efficiency and maximum luminance of the green TOLEDs achieve 63.5 cd·A-1 and 17 873 cd·m-2, respectively, when the multilayer structure of the cGL is Al(3 nm)/c60(5 nm)/ZnPc(5 nm)/MoO3(3 nm).
A facile synthetic approach to access of 3H- pyrrolo[ 2,3c] quinoline derivatives has been achieved by a sequential I2- promoted cyclization/ Staudinger/ aza- Wittig/ dehydroaromatization reaction. The targeted produc...
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A facile synthetic approach to access of 3H- pyrrolo[ 2,3c] quinoline derivatives has been achieved by a sequential I2- promoted cyclization/ Staudinger/ aza- Wittig/ dehydroaromatization reaction. The targeted products were received in moderate to good yields ( 62- 81%). The broad substrate scope and easy availability of the starting materials make this method a valuable tool for generating 3H- pyrrolo[ 2,3- c] quinoline products.
Previous work has demonstrated that variants of a heme protein, Rhodothermus marinus cytochrome c ( Rma cyt c ), catalyze abiological carbene boron-hydrogen (B-H) bond insertion with high efficiency and selectivity. H...
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Previous work has demonstrated that variants of a heme protein, Rhodothermus marinus cytochrome c ( Rma cyt c ), catalyze abiological carbene boron-hydrogen (B-H) bond insertion with high efficiency and selectivity. Here we investigated this carbon-boron bond-forming chemistry with cyclic, lactone-based carbenes. Using directed evolution, we obtained a Rma cyt c variant BOR (LAc) that shows high selectivity and efficiency for B-H insertion of 5- and 6-membered lactone carbenes (up to 24,500 total turnovers and 97.1:2.9 enantiomeric ratio). The enzyme shows low activity with a 7-membered lactone carbene. computational studies revealed a highly twisted geometry of the 7-membered lactone carbene intermediate relative to 5- and 6-membered ones. Directed evolution of cytochrome c together with computational characterization of key iron-carbene intermediates has allowed us to expand the scope of enzymaticcarbene B-H insertion to produce new lactone-based organoborons.
Nanostructured transition metal sulfides are promising anode materials for lithium-ion batteries. Nevertheless, it is still a great challenge to prepare capacity-improved electrodes without reducing their rate capabil...
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Nanostructured transition metal sulfides are promising anode materials for lithium-ion batteries. Nevertheless, it is still a great challenge to prepare capacity-improved electrodes without reducing their rate capability and cycle stability. In this paper, we present a c/co9S8@SnS(2)composite material by loading SnS(2)nanocrystals onto MOF-derived c/co(9)S(8)nanostructures. The c/co9S8@SnS(2)composite has multiple active sites to store lithium ions. The specificcapacity reaches 3.1 mAh cm(-2)when the current density is 0.224 mA cm(-2). The asynchronous electrochemical reaction between co(9)S(8)and SnS(2)offsets the volume expansion of the anode material. Meanwhile, the compact adhesion of carbon layers on the interfaces suppresses the destruction of the anode during the charging-discharging processes. consequently, the synthesized electrode presents favorable capacity with high current density or under long-term cycling conditions. The prepared battery has a reversible specificcapacity of 0.452 mAh cm(-2)and a coulomb efficiency of 99.7% after 500 cycles with a high current density of 2.24 mA cm(-2). The research results obtained in this work provides a feasible strategy to improve the performance of electrodes systematically.
The aim of this work is to develop high-performance adhesives to join carbon fiber reinforced composites (c/c) for use in aerospace applications;in order to guarantee sound mechanical strength, a low coefficient of th...
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The aim of this work is to develop high-performance adhesives to join carbon fiber reinforced composites (c/c) for use in aerospace applications;in order to guarantee sound mechanical strength, a low coefficient of thermal expansion, and ease of application on large components. Several different adhesive formulations, based on phenolic or cyanate-ester resins (charged with the maximum experimentally feasible amount of carbon-based fillers), are developed and tested. The measurements of the lap shear strength at room temperature of the c/c joined by means of one phenolic and one cyanate ester-based resin demonstrates that these formulations are the most suitable for the given application. A complete characterization, by means of viscosimetry, dilatometry, and thermal gravimetric analysis, coupled with gas analysis by means of mass spectroscopy, confirms that the phenolic-based formulation is the most promising joining material. A nano-indenter is used to obtain its Young modulus and hardness, both inside the joint and as a bulk cured adhesive.
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