Nematic topological superconducting phase in Nb-doped Bi2Se3

A nematic topological superconductor has an order parameter symmetry, which spontaneously breaks the crystalline symmetry in its superconducting state. This state can be observed, for example, by thermodynamic or upper critical field experiments in which a magnetic field is rotated with respect to the crystalline axes. The corresponding physical quantity then directly reflects the symmetry of the order parameter. We present a study on the superconducting upper critical field of the Nb-doped topological insulator NbxBi2Se3 for various magnetic field orientations parallel and perpendicular to the basal plane of the Bi2Se3 layers. The data were obtained by two complementary experimental techniques, magnetoresistance and DC magnetization, on three different single crystalline samples of the same batch. Both methods and all samples show with perfect agreement that the in-plane upper critical fields clearly demonstrate a two-fold symmetry that breaks the three-fold crystal symmetry. The two-fold symmetry is also found in the absolute value of the magnetization of the initial zero-field-cooled branch of the hysteresis loop and in the value of the thermodynamic contribution above the irreversibility field, but also in the irreversible properties such as the value of the characteristic irreversibility field and in the width of the hysteresis loop. This provides strong experimental evidence that Nb-doped Bi2Se3 is a nematic topological superconductor similar to the Cu- and Sr-doped Bi2Se3

A Case Study of Phonics among Primary School Students

Phonics is a widely implemented teaching approach in primary schools in many English speaking countries. Through a flexural development, the teaching approach has been proved to be an efficient way of improving children’s decoding, spelling and general reading ability. This paper reports case study of presenting phonics to 10 students in Grade 3 in China. The study shows that phonics teaching can help the students to form a connection between words and their pronunciation, hence help students to acquire the ability to decode and spell new words in their further reading

SeDR: Segment Representation Learning for Long Documents Dense Retrieval

Recently, Dense Retrieval (DR) has become a promising solution to document retrieval, where document representations are used to perform effective and efficient semantic search. However, DR remains challenging on long documents, due to the quadratic complexity of its Transformer-based encoder and the finite capacity of a low-dimension embedding. Current DR models use suboptimal strategies such as truncating or splitting-and-pooling to long documents leading to poor utilization of whole document information. In this work, to tackle this problem, we propose Segment representation learning for long documents Dense Retrieval (SeDR). In SeDR, Segment-Interaction Transformer is proposed to encode long documents into document-aware and segment-sensitive representations, while it holds the complexity of splitting-and-pooling and outperforms other segment-interaction patterns on DR. Since GPU memory requirements for long document encoding causes insufficient negatives for DR training, Late-Cache Negative is further proposed to provide additional cache negatives for optimizing representation learning. Experiments on MS MARCO and TREC-DL datasets show that SeDR achieves superior performance among DR models, and confirm the effectiveness of SeDR on long document retrieval

Isolation Housing Exacerbates Alzheimer\u27s Disease-Like Pathophysiology in Aged APP/PS1 Mice

BACKGROUND: Alzheimer\u27s disease is a neurodegenerative disease characterized by gradual declines in social, cognitive, and emotional functions, leading to a loss of expected social behavior. Social isolation has been shown to have adverse effects on individual development and growth as well as health and aging. Previous experiments have shown that social isolation causes an early onset of Alzheimer\u27s disease-like phenotypes in young APP695/PS1-dE9 transgenic mice. However, the interactions between social isolation and Alzheimer\u27s disease still remain unknown. METHODS: Seventeen-month-old male APP695/PS1-dE9 transgenic mice were either singly housed or continued group housing for 3 months. Then, Alzheimer\u27s disease-like pathophysiological changes were evaluated by using behavioral, biochemical, and pathological analyses. RESULTS: Isolation housing further promoted cognitive dysfunction and Aβ plaque accumulation in the hippocampus of aged APP695/PS1-dE9 transgenic mice, associated with increased γ-secretase and decreased neprilysin expression. Furthermore, exacerbated hippocampal atrophy, synapse and myelin associated protein loss, and glial neuroinflammatory reactions were observed in the hippocampus of isolated aged APP695/PS1-dE9 transgenic mice. CONCLUSIONS: The results demonstrate that social isolation exacerbates Alzheimer\u27s disease-like pathophysiology in aged APP695/PS1-dE9 transgenic mice, highlighting the potential role of group life for delaying or counteracting the Alzheimer\u27s disease process

Deletion of Aquaporin-4 in APP/PS1 Mice Exacerbates Brain Aβ Accumulation and Memory Deficits

BACKGROUND: Preventing or reducing amyloid-beta (Aβ) accumulation in the brain is an important therapeutic strategy for Alzheimer\u27s disease (AD). Recent studies showed that the water channel aquaporin-4 (AQP4) mediates soluble Aβ clearance from the brain parenchyma along the paravascular pathway. However the direct evidence for roles of AQP4 in the pathophysiology of AD remains absent. RESULTS: Here, we reported that the deletion of AQP4 exacerbated cognitive deficits of 12-moth old APP/PS1 mice, with increases in Aβ accumulation, cerebral amyloid angiopathy and loss of synaptic protein and brain-derived neurotrophic factor in the hippocampus and cortex. Furthermore, AQP4 deficiency increased atrophy of astrocytes with significant decreases in interleukin-1 beta and nonsignificant decreases in interleukin-6 and tumor necrosis factor-alpha in hippocampal and cerebral samples. CONCLUSIONS: These results suggest that AQP4 attenuates Aβ pathogenesis despite its potentially inflammatory side-effects, thus serving as a promising target for treating AD

Chalcogenide Glass-on-Graphene Photonics

Two-dimensional (2-D) materials are of tremendous interest to integrated photonics given their singular optical characteristics spanning light emission, modulation, saturable absorption, and nonlinear optics. To harness their optical properties, these atomically thin materials are usually attached onto prefabricated devices via a transfer process. In this paper, we present a new route for 2-D material integration with planar photonics. Central to this approach is the use of chalcogenide glass, a multifunctional material which can be directly deposited and patterned on a wide variety of 2-D materials and can simultaneously function as the light guiding medium, a gate dielectric, and a passivation layer for 2-D materials. Besides claiming improved fabrication yield and throughput compared to the traditional transfer process, our technique also enables unconventional multilayer device geometries optimally designed for enhancing light-matter interactions in the 2-D layers. Capitalizing on this facile integration method, we demonstrate a series of high-performance glass-on-graphene devices including ultra-broadband on-chip polarizers, energy-efficient thermo-optic switches, as well as graphene-based mid-infrared (mid-IR) waveguide-integrated photodetectors and modulators

Progress in Understanding the Mechanism by Which Probiotics Alletivate Hyperuricemia

Hyperuricemia (HUA) is a disease caused by excessive production and/or inadequate excretion of uric acid (UA) in the body, and persistent HUA can lead to gout. Asymptomatic HUA is closely related to other metabolic diseases, such as chronic kidney disease, diabetes and cardiovascular disease. Probiotic intervention is a potentially safe, cost-effective treatment to improve HUA. This paper mainly describes the mechanisms of action of probiotics in reducing the level of uric acid, including inhibiting xanthine oxidase activity, absorbing and degrading purines in the intestine, regulating intestinal flora homeostasis and restoring intestinal barrier function. In addition, probiotics can promote uric acid excretion and consequently reduced uric acid levels by promoting the expression of urate transport proteins and inhibiting the expression of urate reabsorbing proteins. Probiotics have great potential in alleviating HUA. This review hopes to provide a theoretical basis for subsequent research