Spontaneous rotational symmetry breaking in KTaO3_3 interface superconductors

Strongly correlated electrons could display intriguing spontaneous broken symmetries in the ground state. Understanding these symmetry breaking states is fundamental to elucidate the various exotic quantum phases in condensed matter physics. Here, we report an experimental observation of spontaneous rotational symmetry breaking of the superconductivity at the interface of YAlO$_3$/KTaO$_3$ (111) with a superconducting transition temperature of 1.86 K. Both the magnetoresistance and upper critical field in an in-plane field manifest striking twofold symmetric oscillations deep inside the superconducting state, whereas the anisotropy vanishes in the normal state, demonstrating that it is an intrinsic property of the superconducting phase. We attribute this behavior to the mixed-parity superconducting state, which is an admixture of $s$-wave and $p$-wave pairing components induced by strong spin-orbit coupling. Our work demonstrates an unconventional nature of the pairing interaction in the KTaO$_3$ interface superconductor, and provides a new platform to clarify a delicate interplay of electron correlation and spin-orbit coupling.Comment: 7 pages, 4 figure

Uncovering the Functional Link Between SHANK3 Deletions and Deficiency in Neurodevelopment Using iPSC-Derived Human Neurons

SHANK3 mutations, including de novo deletions, have been associated with autism spectrum disorders (ASD). However, the effects of SHANK3 loss of function on neurodevelopment remain poorly understood. Here we generated human induced pluripotent stem cells (iPSC) in vitro, followed by neuro-differentiation and lentivirus-mediated shRNA expression to evaluate how SHANK3 knockdown affects the in vitro neurodevelopmental process at multiple time points (up to 4 weeks). We found that SHANK3 knockdown impaired both early stage of neuronal development and mature neuronal function, as demonstrated by a reduction in neuronal soma size, growth cone area, neurite length and branch numbers. Notably, electrophysiology analyses showed defects in excitatory and inhibitory synaptic transmission. Furthermore, transcriptome analyses revealed that multiple biological pathways related to neuron projection, motility and regulation of neurogenesis were disrupted in cells with SHANK3 knockdown. In conclusion, utilizing a human iPSC-based neural induction model, this study presented combined morphological, electrophysiological and transcription evidence that support that SHANK3 as an intrinsic, cell autonomous factor that controls cellular function development in human neurons

Structure determination of DNA methylation lesions N1-meA and N3-meC in duplex DNA using a cross-linked protein–DNA system

N1-meA and N3-meC are cytotoxic DNA base methylation lesions that can accumulate in the genomes of various organisms in the presence of SN2 type methylating agents. We report here the structural characterization of these base lesions in duplex DNA using a cross-linked protein–DNA crystallization system. The crystal structure of N1-meA:T pair shows an unambiguous Hoogsteen base pair with a syn conformation adopted by N1-meA, which exhibits significant changes in the opening, roll and twist angles as compared to the normal A:T base pair. Unlike N1-meA, N3-meC does not establish any interaction with the opposite G, but remains partially intrahelical. Also, structurally characterized is the N6-meA base modification that forms a normal base pair with the opposite T in duplex DNA. Structural characterization of these base methylation modifications provides molecular level information on how they affect the overall structure of duplex DNA. In addition, the base pairs containing N1-meA or N3-meC do not share any specific characteristic properties except that both lesions create thermodynamically unstable regions in a duplex DNA, a property that may be explored by the repair proteins to locate these lesions

Synthesis of a FTO Inhibitor with Anticonvulsant Activity

We describe the rationale for and the synthesis of a new class of compounds utilizing a modular approach that are designed to mimic ascorbic acid and to inhibit 2-oxoglutarate-dependent hydroxylases. Preliminary characterization of one of these compounds indicates in vivo anticonvulsant activity (6 Hz mouse model) at nontoxic doses, inhibition of the 2-oxoglutarate-dependent hydroxylase FTO, and expected increase in cellular N6-methyladenosine. This compound is also able to modulate various microRNA, an interesting result in light of the recent view that modulation of microRNAs may be useful for the treatment of CNS disease

MCMs in Cancer: Prognostic Potential and Mechanisms

Enabling replicative immortality and uncontrolled cell cycle are hallmarks of cancer cells. Minichromosome maintenance proteins (MCMs) exhibit helicase activity in replication initiation and play vital roles in controlling replication times within a cell cycle. Overexpressed MCMs are detected in various cancerous tissues and cancer cell lines. Previous studies have proposed MCMs as promising proliferation markers in cancers, while the prognostic values remain controversial and the underlying mechanisms remain unascertained. This review provides an overview of the significant findings regarding the cellular and tumorigenic functions of the MCM family. Besides, current evidence of the prognostic roles of MCMs is retrospectively reviewed. This work also offers insight into the mechanisms of MCMs prompting carcinogenesis and adverse prognosis, providing information for future research. Finally, MCMs in liver cancer are specifically discussed, and future perspectives are provided

Synthesis of zeolite Beta containing ultra-small CoO particles for ethylbenzene oxidation

Zeolite Beta containing ultra-small CoO particles was synthesized from a one-step hydrothermal process. The synthesis route involves the pre-mixture of hydrofluoric acid with tetraethylammonium hydroxide (in a molar ratio of 1.3-1.5:1) before the addition of a silicon and cobalt source. Investigations by scanning electron microscopy, X-ray diffraction, UV-Vis spectroscopy, X-ray photoelectron spectroscopy, H-2-temperature-programmed reduction and transmission electron microscopy confirm the presence of ultra-small CoO particles in the zeolite Beta structure. The ultra-small CoO particles in zeolite Beta present high stability against both oxidation and reduction atmospheres at high temperatures. The catalytic performance of the CoO-containing zeolite Beta catalysts was compared with other Co-containing zeolites by evaluating ethylbenzene oxidation reactivity. The CoO-containing zeolite Beta exhibits high ethylbenzene conversion and high selectivity to acetophenone and 1-phenylethanol. The high activity of this catalyst system can be attributed to the high dispersion of the ultra-small CoO particles in the Beta structure. (C) 2017, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved

Flame-Retardant GF-PSB/DOPO-POSS Composite with Low Dk/Df and High Thermal Stability for High-Frequency Copper Clad Applications

In the field of high-frequency communications devices, there is an urgent need to develop high-performance copper clad laminates (CCLs) with low dielectric loss (Df) plus good flame retardancy and thermal stability. The hydrocarbon resin styrene-butadiene block copolymer (PSB) was modified with the flame-retardant 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide/polyhedral oligomeric silsesquioxanes (DOPO-POSS) to meet the demands of high-frequency and high-speed applications. The resulting DOPO-POSS-modified PSB was used as the resin matrix along with other additives to fabricate PSB/DOPO-POSS laminates. At a high-frequency of 10 GHz, the laminates containing 20 wt.% of DOPO-POSS and with a thickness of 0.09 mm exhibited a Df of 0.00328, which is much lower compared with the commercial PSB/PX-200 composite (Df: 0.00498) and the PSB without flame retardancy (Df: 0.00453). Afterwards, glass fiber cloth (GF) was used as a reinforcing material to manufacture GF-PSB/DOPO-POSS composite laminates with a thickness of 0.25 mm. The flame retardancy of GF-PSB/DOPO-POSS composite laminate reached vertical burning (UL-94) V-1 grade, and GF-PSB/DOPO-POSS exhibited higher thermal and dynamic mechanical properties than GF-PSB/PX-200. The results of a limited oxygen index (LOI) and self-extinguishing time tests also demonstrated the superior flame-retardant performance of DOPO-POSS compared with PX-200. The investigation indicates that GF-PSB/DOPO-POSS composite laminates have significant potential for use in fabricating a printed circuit board (PCB) for high-frequency and high-speed applications