Row and Bounded Polymorphism via Disjoint Polymorphism

Polymorphism and subtyping are important features in mainstream OO languages. The most common way to integrate the two is via ?_{< :} style bounded quantification. A closely related mechanism is row polymorphism, which provides an alternative to subtyping, while still enabling many of the same applications. Yet another approach is to have type systems with intersection types and polymorphism. A recent addition to this design space are calculi with disjoint intersection types and disjoint polymorphism. With all these alternatives it is natural to wonder how they are related. This paper provides an answer to this question. We show that disjoint polymorphism can recover forms of both row polymorphism and bounded polymorphism, while retaining key desirable properties, such as type-safety and decidability. Furthermore, we identify the extra power of disjoint polymorphism which enables additional features that cannot be easily encoded in calculi with row polymorphism or bounded quantification alone. Ultimately we expect that our work is useful to inform language designers about the expressive power of those common features, and to simplify implementations and metatheory of feature-rich languages with polymorphism and subtyping

Pressure tuning of optical reflectivity in LuH2

Recently, the claim of room-temperature superconductivity in nitrogen-doped lutetium hydride at near-ambient conditions has attracted tremendous attention. Criticism of the work rises shortly, while further explorations are needed to settle the dispute. One of the intriguing observations is the pressured-induced color change, which has been reproduced in the lutetium dihydride LuH2 while its mechanism remains unclear. Through optical reflectivity measurements of LuH2 in the visible to near-infrared region, we observe strong light absorption next to the sharp plasmon resonance, which continuously shifts to higher energies with increasing pressure. It gives rise to the increased reflection of red light and suppressed reflection of blue light. Our work sheds light on resolving the puzzles regarding the pressure induced color change in LuH2.Comment: 8 pages, 6 figure

Largely tunable band structures of few-layer InSe by uniaxial strain

Due to the strong quantum confinement effect, few-layer {\gamma}-InSe exhibits a layer-dependent bandgap, spanning the visible and near infrared regions, and thus recently draws tremendous attention. As a two-dimensional material, the mechanical flexibility provides an additional tuning knob for the electronic structure. Here, for the first time, we engineer the band structures of few-layer and bulk-like InSe by uniaxial tensile strain, and observe salient shift of photoluminescence (PL) peaks. The shift rate of the optical gap is approximately 90-100 meV per 1% strain for 4- to 8-layer samples, which is much larger than that for the widely studied MoS2 monolayer. Density functional calculations well reproduce the observed layer-dependent bandgaps and the strain effect, and reveal that the shift rate decreases with increasing layer number for few-layer InSe. Our study demonstrates that InSe is a very versatile 2D electronic and optoelectronic material, which is suitable for tunable light emitters, photo-detectors and other optoelectronic devices.Comment: submitte

Dopamine depletion and subcortical dysfunction disrupt cortical synchronization and metastability affecting cognitive function in Parkinson's disease

Parkinson's disease (PD) is primarily characterized by the loss of dopaminergic cells and atrophy in subcortical regions. However, the impact of these pathological changes on large‐scale dynamic integration and segregation of the cortex are not well understood. In this study, we investigated the effect of subcortical dysfunction on cortical dynamics and cognition in PD. Spatiotemporal dynamics of the phase interactions of resting‐state blood‐oxygen‐level‐dependent signals in 159 PD patients and 152 normal control (NC) individuals were estimated. The relationships between subcortical atrophy, subcortical–cortical fiber connectivity impairment, cortical synchronization/metastability, and cognitive performance were then assessed. We found that cortical synchronization and metastability in PD patients were significantly decreased. To examine whether this is an effect of dopamine depletion, we investigated 45 PD patients both ON and OFF dopamine replacement therapy, and found that cortical synchronization and metastability are significantly increased in the ON state. The extent of cortical synchronization and metastability in the OFF state reflected cognitive performance and mediates the difference in cognitive performance between the PD and NC groups. Furthermore, both the thalamic volume and thalamocortical fiber connectivity had positive relationships with cortical synchronization and metastability in the dopaminergic OFF state, and mediate the difference in cortical synchronization between the PD and NC groups. In addition, thalamic volume also reflected cognitive performance, and cortical synchronization/metastability mediated the relationship between thalamic volume and cognitive performance in PD patients. Together, these results highlight that subcortical dysfunction and reduced dopamine levels are responsible for decreased cortical synchronization and metastability, further affecting cognitive performance in PD. This might lead to biomarkers being identified that can predict if a patient is at risk of developing dementia

Hydrothermally synthesized CeO2 nanowires for H2S sensing at room temperature

CeO2 nanowires were synthesized using a facile hydrothermal process without any surfactant, and their morphological, structural and gas sensing properties were systematically investigated. The CeO2 nanowires with an average diameter of 12.5 nm had a face-centered cubic fluorite structure and grew along [111] of CeO2. At the room temperature of 25 °C, hydrogen sulfide (H2S) gas sensor based on the CeO2 nanowires showed excellent sensitivity, low detection limit (50 ppb), and short response and recovery time (24 s and 15 s for 50 ppb H2S, respectively)

Nuclear miR-150 enhances hepatic lipid accumulation by targeting RNA transcripts overlapping the PLIN2 promoter

Summary: Alcohol-associated liver disease is a prevalent chronic liver disease caused by excessive ethanol consumption. This study aims to investigate the role of miR-150 in regulating hepatic lipid homeostasis in alcoholic fatty liver (AFL). miR-150 was mainly distributed in the nucleus of hepatocytes and correlated with the degree of liver injury. The decreased expression of miR-150 observed in AFL was a compensatory response to ethanol-induced hepatic steatosis. Overexpression of miR-150 facilitated hepatic lipid accumulation in cellulo and exacerbated ethanol-induced liver steatosis in vivo. In silico analysis identified perilipin-2 (PLIN2) as a potential target gene of miR-150. miR-150 activated PLIN2 transcription by directly binding the RNA transcripts overlapping PLIN2 promoter and facilitating the recruitment of DNA helicase DHX9 and RNA polymeraseⅡ. Overall, our study provides fresh insights into the homeostasis regulation of hepatic steatosis induced by ethanol and identifies miR-150 as a pro-steatosis effector driving transcriptional PLIN2 gene activation

Molecular dynamics simulation of bulk nano-oxygen-bubble fuel under high-pressure transport and sudden pressure drop process

Aiming at the injection process of bubbly flow fuel, the molecular dynamics simulation was performed to study the change of bulk nano-oxygen-bubble (BNB) fuel during high-pressure transport and sudden pressure drop process. The static processes of BNB fuel containing different oxygen molecules numbers are explored in depth at normal temperature and pressure and pressure increase as well as the dynamic process under high-flow-rate-coupled sudden pressure drop. The results show that after adding BNB, the BNB contour increases first and then decreases. Increasing the number of oxygen molecules added at normal temperature and pressure shortens the BNB stabilization time and improves BNB stability. The BNB inner density in fuel is much smaller than that in water. Under high-pressure condition, the BNB which can be stabilized in the fuel at normal temperature and pressure quickly dissolves and disappears due to the increase in solubility of oxygen, resulting in a decrease in the oxygen molecule potential energy. Increasing the number of oxygen molecules added has only a weak slowing down effect on the dissolution rate. During the high-speed jetting of fuel at the nozzle, BNB promotes fuel droplet fragmentation and increases the oxygen concentration around the fuel droplet. In this process, the oxygen molecules do work on the fuel and their kinetic energy decreases. Increasing the number of oxygen molecules added reduces fuel breakup time and improves the quality of gas mixture formed. The results of this study can provide a reference for the micro-mechanism of BNB on improving the atomization characteristics of bubbly flow fuel

Evaporation Characteristics and Morphological Evolutions of Fuel Droplets After Hitting Different Wettability Surfaces

To solve the wall-wetting problem in internal combustion engines, the physical and chemical etching 11 methods are used to prepare different wettability surfaces with various microstructures. The evaporation 12 characteristics and morphological evolution processes of diesel and n-butanol droplets after hitting the various 13 surfaces are investigated. The results show that the surface microstructures increase the surface roughness (Ra), 14 enhancing the oleophilic property of the oleophilic surfaces. Compared to n-butanol droplets, the same surface 15 shows stronger oleophobicity to diesel droplets. When a droplet hits an oleophilic property surface with a lower 16 temperature, the stronger the oleophilicity, the shorter the evaporation time. For oleophilic surfaces, larger Ra leads to a higher Leidenfrost temperature (TLeid ). The low TLeid 17 caused by enhanced oleophobicity, dense 18 microstructures and increased convex dome height facilitates droplet rebound and promotes the evaporation of 19 the wall-impinging droplets into the cylinder. The evaporation rate of the droplets is not only related to the 20 characteristics of the solid surfaces and the fuel droplets but also affected by the heat transfer rate of the droplets 21 at different boiling regimes. The spreading diameter of a droplet on an oleophobic surface varies significantly 22 less with time than that on an oleophilic surface under the same surface temperature