136 research outputs found
Should bike sharing continue operating during the COVID-19 pandemic? Empirical findings from Nanjing, China
Coronavirus disease 2019 (COVID-19) has triggered a worldwide outbreak of
pandemic, and transportation services have played a key role in coronavirus
transmission. Although not crowded in a confined space like a bus or a metro
car, bike sharing users will be exposed to the bike surface and take the
transmission risk. During the COVID-19 pandemic, how to meet user demand and
avoid virus spreading has become an important issue for bike sharing. Based on
the trip data of bike sharing in Nanjing, China, this study analyzes the travel
demand and operation management before and after the pandemic outbreak from the
perspective of stations, users, and bikes. Semi-logarithmic
difference-in-differences model, visualization methods, and statistic indexes
are applied to explore the transportation service and risk prevention of bike
sharing during the pandemic. The results show that pandemic control strategies
sharply reduced user demand, and commuting trips decreased more significantly.
Some stations around health and religious places become more important. Men and
older adults are more dependent on bike sharing systems. Besides, the trip
decrease reduces user contact and increases idle bikes. And a new concept of
user distancing is proposed to avoid transmission risk and activate idle bikes.
This study evaluates the role of shared micro-mobility during the COVID-19
pandemic, and also inspires the blocking of viral transmission within the city.Comment: 30 pages, 7 figures, 6 table
Tera-sample-per-second arbitrary waveform generation in the synthetic dimension
The synthetic dimension opens new horizons in quantum physics and topological
photonics by enabling new dimensions for field and particle manipulations. The
most appealing property of the photonic synthetic dimension is its ability to
emulate high-dimensional optical behavior in a unitary physical system. Here we
show that the photonic synthetic dimension can transform technical problems in
photonic systems between dimensionalities, providing unexpected solutions to
technical problems that are otherwise challenging. Specifically, we propose and
experimentally demonstrate a photonic Galton board (PGB) in the temporal
synthetic dimension, in which the temporal high-speed challenge is converted
into a spatial fiber-optic length matching problem, leading to the experimental
generation of tera-sample-per-second arbitrary waveforms. Limited by the speed
of the measurement equipment, waveforms with sampling rates of up to 341.53
GSa/s are recorded. Our proposed PGB operating in the temporal synthetic
dimension breaks the speed limit in a physical system, bringing arbitrary
waveform generation into the terahertz regime. The concept of dimension
conversion offers possible solutions to various physical dimension-related
problems, such as super-resolution imaging, high-resolution spectroscopy, time
measurement, etc
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LIN28 Is Involved in Glioma Carcinogenesis and Predicts Outcomes of Glioblastoma Multiforme Patients
LIN28, an evolutionarily conversed RNA binding protein which can bind to the terminal loops of let-7 family microRNA precursors and block their processing to maturation, is highly expressed in several subsets of tumors that carry poor prognoses, such as ovarian carcinoma, hepatocellular carcinoma, colon carcinoma and germ cell carcinoma. However, there has been no study on the expression of LIN28 in glioma tissues or their importance as a prognostic predictor of glioma patients. This study aimed to examine the expression of LIN28 in glioma and correlate the results to patient outcome. We found that LIN28 expression was significantly higher in the group of patients with a poor prognosis compared to patients with a good prognosis by gene microarray. Log-rank analysis showed patients with higher LIN28 expression level in tumor had a shorter progression-free survival and overall survival times compared to those with lower LIN28 expression level. Similar results were also obtained from the tissue microarray analysis. Univariate and multivariate analyses showed high LIN28 expression was an independent prognostic factor for a shorter progression-free survival and overall survival in GBM patients. Furthermore in vitro experiments showed that down-regulation of LIN28 in U251 and U373 cells caused cell cycle arrest in the G1 phase, delayed cell proliferation, increased apoptosis, and resulted in fewer colonies compared to controls. Summarily, our data provides a potential target for cancer therapy as an approach to overcome the poor options currently available for GBM patients
Facile template-free synthesis of vertically aligned polypyrrole nanosheets on nickel foams for flexible all-solid-state asymmetric supercapacitors
This paper reports a novel and remarkably facile approach towards vertically aligned nanosheets on three-dimensional (3D) Ni foams. Conducting polypyrrole (PPy) sheets were grown on Ni foam through the volatilization of the environmentally friendly solvent from an ethanol–water solution of pyrrole (Py), followed by the polymerization of the coated Py in ammonium persulfate (APS) solution. The PPy-decorated Ni foams and commercial activated carbon (AC) modified Ni foams were employed as the two electrodes for the assembly of flexible all-solid-state asymmetric supercapacitors. The sheet-like structure of PPy and the macroporous feature of the Ni foam, which render large electrode–electrolyte interfaces, resulted in good capacitive performance of the supercapacitors. Moreover, a high energy density of ca. 14 Wh kg−1 and a high power density of 6.2 kW kg−1 were achieved for the all-solid-state asymmetric supercapacitors due to the wide cell voltage window
Investigation of systemic immune-inflammation index, neutrophil/high-density lipoprotein ratio, lymphocyte/high-density lipoprotein ratio, and monocyte/high-density lipoprotein ratio as indicators of inflammation in patients with schizophrenia and bipolar disorder
BackgroundThe systemic immune-inflammation index (SII), system inflammation response index (SIRI), neutrophil/high-density lipoprotein (HDL) ratio (NHR), lymphocyte/HDL ratio (LHR), monocyte/HDL ratio (MHR), and platelet/HDL ratio (PHR) have been recently investigated as new markers for inflammation. The purpose of this research is to use large-scale clinical data to discuss and compare the predictive ability of the SII, SIRI, NHR, LHR, MHR, and PHR in patients with schizophrenia (SCZ) and bipolar disorder (BD), to investigate potential biomarkers.Materials and methodsIn this retrospective, naturalistic, cross-sectional study, we collected the hematological parameter data of 13,329 patients with SCZ, 4,061 patients with BD manic episodes (BD-M), and 1,944 patients with BD depressive episodes (BD-D), and 5,810 healthy subjects served as the healthy control (HC) group. The differences in the SII, SIRI, NHR, LHR, MHR, and PHR were analyzed, and a receiver operating characteristic (ROC) curve was used to analyze the diagnostic potential of these parameters.ResultsCompared with the HC group, the values of the SII, SIRI, NHR, LHR, MHR, and PHR and the levels of neutrophils, monocytes, and triglycerides (TG) were higher in SCZ and BD groups, and levels of platelets, cholesterol (CHO), HDL, low-density lipoprotein (LDL), and apoprotein B (Apo B) were lower in SCZ and BD groups. Compared to the BD group, the values of the SIRI, lymphocytes, monocytes, and HDL were lower and the values of the SII, NHR, PHR, and platelet were higher in the SCZ group. In contrast to the BD-D group, the values of the SII; SIRI; NHR; and MHR; and levels of neutrophils, monocytes, and platelets were higher in the BD-M group, and the levels of CHO, TG, LDL, and Apo B were lower in the BD-M group. The MHR and NHR were predictors for differentiating the SCZ group from the HC group; the SIRI, NHR, and MHR were predictors for differentiating the BD-M group from the HC group; and the MHR was a predictor for differentiating the BD-D group from the HC group. The combination model of the indicators improved diagnostic effectiveness.ConclusionOur study highlights the role of systemic inflammation in the pathophysiology of SCZ, BD-M, and BD-D, the association between inflammation and lipid metabolism, and these inflammation and lipid metabolism indicators showed different variation patterns in SCZ, BD-D, and BD-M
Low Resistance Ohmic Contact to P-type Monolayer WSe2
Advanced microelectronics in the future may require semiconducting channel
materials beyond silicon. Two-dimensional (2D) semiconductors, characterized by
their atomically thin thickness, hold immense promise for high-performance
electronic devices at the nanometer scale with lower heat dissipation. One
challenge for achieving high-performance 2D semiconductor field effect
transistors (FET), especially for p-type materials, is the high electrical
contact resistance present at the metal-semiconductor interface. In
conventional bulk semiconductors, low resistance ohmic contact is realized
through heavy substitutional doping with acceptor or donor impurities at the
contact region. The strategy of substitutional doping, however, does not work
for p-type 2D semiconductors such as monolayer tungsten diselenide (WSe).In
this study, we developed highly efficient charge-transfer doping with
WSe/-RuCl heterostructures to achieve low-resistance ohmic
contact for p-type WSe transistors. We show that a hole doping as high as
310 cm can be achieved in the WSe-RuCl
heterostructure due to its type-III band alignment. It results in an Ohmic
contact with resistance lower than 4 k Ohm m at the p-type monolayer
WSe/metal junction. at room temperature. Using this low-resistance contact,
we demonstrate high-performance p-type WSe transistors with a saturation
current of 35 A m and an I/I ratio
exceeding 10 It could enable future microelectronic devices based on 2D
semiconductors and contribute to the extension of Moore's law
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Low Resistance Contact to P‑Type Monolayer WSe2
Advanced microelectronics in the future may require semiconducting channel materials beyond silicon. Two-dimensional (2D) semiconductors, with their atomically thin thickness, hold great promise for future electronic devices. One challenge to achieving high-performance 2D semiconductor field effect transistors (FET) is the high contact resistance at the metal-semiconductor interface. In this study, we develop a charge-transfer doping strategy with WSe2/α-RuCl3 heterostructures to achieve low-resistance ohmic contact for p-type monolayer WSe2 transistors. We show that hole doping as high as 3 × 1013 cm-2 can be achieved in the WSe2/α-RuCl3 heterostructure due to its type-III band alignment, resulting in an ohmic contact with resistance of 4 kΩ μm. Based on that, we demonstrate p-type WSe2 transistors with an on-current of 35 μA·μm-1 and an ION/IOFF ratio exceeding 109 at room temperature
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