The purpose of this study was to identify personality factor-associated predictors of smartphone addiction predisposition (SAP). Participants were 2,573 men and 2,281 women (n = 4,854) aged 20-49 ...years (Mean ± SD: 33.47 ± 7.52); participants completed the following questionnaires: the Korean Smartphone Addiction Proneness Scale (K-SAPS) for adults, the Behavioral Inhibition System/Behavioral Activation System questionnaire (BIS/BAS), the Dickman Dysfunctional Impulsivity Instrument (DDII), and the Brief Self-Control Scale (BSCS). In addition, participants reported their demographic information and smartphone usage pattern (weekday or weekend average usage hours and main use). We analyzed the data in three steps: (1) identifying predictors with logistic regression, (2) deriving causal relationships between SAP and its predictors using a Bayesian belief network (BN), and (3) computing optimal cut-off points for the identified predictors using the Youden index. Identified predictors of SAP were as follows: gender (female), weekend average usage hours, and scores on BAS-Drive, BAS-Reward Responsiveness, DDII, and BSCS. Female gender and scores on BAS-Drive and BSCS directly increased SAP. BAS-Reward Responsiveness and DDII indirectly increased SAP. We found that SAP was defined with maximal sensitivity as follows: weekend average usage hours > 4.45, BAS-Drive > 10.0, BAS-Reward Responsiveness > 13.8, DDII > 4.5, and BSCS > 37.4. This study raises the possibility that personality factors contribute to SAP. And, we calculated cut-off points for key predictors. These findings may assist clinicians screening for SAP using cut-off points, and further the understanding of SA risk factors.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We examined the effects of empagliflozin, a selective inhibitor of Na
-glucose cotransporter 2, on mitochondrial quality control and autophagy in renal tubular cells in a diabetic environment in vivo ...and in vitro. Human renal proximal tubular cells (hRPTCs) were incubated under high-glucose conditions. Diabetes was induced with streptozotocin in male C57BL/6J mice. Improvements in mitochondrial biogenesis and balanced fusion-fission protein expression were noted in hRPTCs after treatment with empagliflozin in high-glucose media. Empagliflozin also increased autophagic activities in renal tubular cells in the high-glucose environment, which was accompanied with mammalian target of rapamycin inhibition. Moreover, reduced mitochondrial reactive oxygen species production and decreased apoptotic and fibrotic protein expression were observed in hRPTCs after treatment with empagliflozin, even in the hyperglycemic circumstance. Importantly, empagliflozin restored AMP-activated protein kinase-α phosphorylation and normalized levels of AMP-to-ATP ratios in hRPTCs subjected to a high-glucose environment, which suggests the way that empagliflozin is involved in mitochondrial quality control. Empagliflozin effectively suppressed Na
-glucose cotransporter 2 expression and ameliorated renal morphological changes in the kidneys of streptozotocin-induced diabetic mice. Electron microscopy analysis showed that mitochondrial fragmentation was decreased and 8-hydroxy-2'-deoxyguanosine content was low in renal tubular cells of empagliflozin treatment groups compared with those of the diabetic control group. We suggest one mechanism related to the renoprotective actions of empagliflozin, which reverse mitochondrial dynamics and autophagy.
We report the presence of defects in CH3NH3PbI3, which is one of the main factors that deteriorates the performance of perovskite solar cells. Although the efficiency of the perovskite solar cells ...has been improved by curing defects using various methods, deeply trapped defects in the perovskite layer have not been systematically studied, and their function is still unclear. The comparison and analysis of defects in differently prepared perovskite solar cells reveals that both solar cells have two kinds of deep level defects (E1 and E2). In the one-pot solution processed solar cell, the defect state E1 is dominant, while E2 is the major defect in the solar cell prepared using the cuboid method. Since the energy level of E1 is higher than that of E2, the cuboid solar cell shows higher open-circuit voltage and efficiency.
Hybrid carbon nanotube composites with two different types of fillers have attracted considerable attention for various advantages. The incorporation of micro-scale secondary fillers creates an ...excluded volume that leads to the increase in the electrical conductivity. By contrast, nano-scale secondary fillers shows a conflicting behavior of the decreased electrical conductivity with micro-scale secondary fillers. Although several attempts have been made in theoretical modeling of secondary-filler composites, the knowledge about how the electrical conductivity depends on the dimension of secondary fillers was not fully understood. This work aims at comprehensive understanding of the size effect of secondary particulate fillers on the electrical conductivity, via the combination of Voronoi geometry induced from Swiss cheese models and the underlying percolation theory. This indicates a transition in the impact of the excluded volume, i.e., the adjustment of the electrical conductivity was measured in cooperation with loading of second fillers with different sizes.
Non‐toxic InP‐based nanocrystals have been developed for promising candidates for commercial optoelectronic applications and they still require further improvement on photophysical properties, ...compared to Cd‐based quantum dots (QDs), for better device efficiency and long‐term stability. It is, therefore, essential to understand the precise mechanism of carrier trapping even in the state‐of‐the‐art InP‐based QD with near‐unity luminescence. Here, it is shown that using time‐resolved spectroscopic measurements of systematically size‐controlled InP/ZnSe/ZnS core/shell/shell QDs with the quantum yield close to one, carrier trapping decreases with increasing the energy difference between band‐edge and trap states, indicating that the process follows the energy gap law, well known in molecular photochemistry for nonradiative internal conversion between two electronic states. Similar to the molecular view of the energy gap law, it is found that the energy gap between the band‐edge and trap states is closely associated with ZnSe phonons that assist carrier trapping into defects in highly luminescent InP/ZnSe/ZnS QDs. These findings represent a striking departure from the generally accepted view of carrier trapping mechanism in QDs in the Marcus normal region, providing a step forward understanding how excitons in nanocrystals interact with traps, and offering valuable guidance for making highly efficient and stable InP‐based QDs.
In InP/ZnSe/ZnS quantum dots with near‐unity luminescence, carrier trapping into shallow defects at a picosecond timescale is a key mechanism to reduce the quantum yield. The carrier trapping assisted by ZnSe phonons can slow down with increasing the energy gap between the band‐edge and shallow trap states.
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•Mg-biochar recovered P and N from SSA and FW as struvite.•PTT Mg-biochar showed higher nutrient recovery than GCB Mg-biochar.•Mg-biochar showed higher struvite selectivity than the ...precipitation in solution.•Nutrients were recovered by adsorption, precipitation and cation-exchange.
The drawback of biochar as a soil ameliorant is its low-nutrient content while the bottleneck of struvite production is its high chemical cost. This drew the idea of using designed biochar for nutrient recovery from nutrient-rich wastewater as struvite. Mg-biochar was used for simultaneous P and N recovery from sewage sludge ash (SSA) and food wastewater (FW) by using ground coffee bean (GCB) and palm tree trunk (PTT) waste. PTT Mg-biochar could recover 92.2% of PO43−-P and 54.8% of NH4+-N while GCB Mg-biochar could recover 79.5% of PO43−-P and 38.6% of NH4+-N. Adsorption, precipitation and cation-exchange mechanisms are involved in the Mg-biochar for the simultaneous recovery of PO43−-P and NH4+-N as struvite. Mg-biochars also showed higher struvite selectivity than the control samples. This method not only supports waste recycling and pollution mitigation but also highlights economical struvite production and the benefits of CO2 sequestration.
A synergic combination of a soluble redox mediator and a protected Li metal electrode to prevent the self‐discharge of the redox mediator is realized by exploiting a 2,2,6,6‐tetramethylpiperidinyl ...1‐oxyl (TEMPO) redox mediator and an Al2O3/PVdF‐HFP composite protective layer (CPL). Stabilization of Li metal by simple CPL coating is effective at suppressing the chemical reduction of the oxidized TEMPO and opens up the possibility of sustainable redox mediation for robust cycling of Li–O2 batteries.
Aims.
We announce the discovery of a microlensing planetary system, in which a sub-Saturn planet is orbiting an ultracool dwarf host.
Methods.
We detected the planetary system by analyzing the ...short-timescale (
t
E
~ 4.4 days) lensing event KMT-2018-BLG-0748. The central part of the light curve exhibits asymmetry due to negative deviations in the rising side and positive deviations in the falling side.
Results.
We find that the deviations are explained by a binary-lens model with a mass ratio between the lens components of
q
~ 2 × 10
−3
. The short event timescale, together with the small angular Einstein radius,
θ
E
~ 0.11 mas, indicate that the mass of the planet host is very small. The Bayesian analysis conducted under the assumption that the planet frequency is independent of the host mass indicates that the mass of the planet is
M
p
= 0.18
−0.10
+0.29
M
J
, and the mass of the host,
M
h
= 0.087
−0.047
+0.138
M
⊙
, is near the star–brown dwarf boundary, but the estimated host mass is sensitive to this assumption about the planet hosting probability. High-resolution follow-up observations would lead to revealing the nature of the planet host.
High-cadence observations of the Galactic bulge by the microlensing surveys led to the discovery of a handful of extremely short-timescale microlensing events that can be attributed to free-floating ...or wide-orbit planets. Here, we report the discovery of another strong free-floating planet candidate, which was found from the analysis of the gravitational microlensing event OGLE-2019-BLG-0551. The light curve of the event is characterized by a very short duration ( 3 days) and a very small amplitude ( 0.1 mag). From modeling of the light curve, we find that the Einstein timescale, day, is much shorter, and the angular Einstein radius, as, is much smaller than those of typical lensing events produced by stellar-mass lenses ( days, mas), indicating that the lens is very likely to be a planetary-mass object. We conduct an extensive search for possible signatures of a companion star in the light curve of the event, finding no significant evidence for the putative host star. For the first time, we also demonstrate that the angular Einstein radius of the lens does not depend on blending in the low-magnification events with strong finite source effects.
Abstract
We present
BVI
surface photometry of 31 dwarf galaxy candidates discovered in a deep image stack from the KMTNet Supernova Program of ∼30 square degrees centered on the nearby NGC 2784 ...galaxy group. Our final images have a 3
σ
surface brightness detection limit of
mag arcsec
−2
. The faintest central surface brightness that we measure is
mag arcsec
−2
. If these candidates are at the distance of NGC 2784, then they have absolute magnitudes greater than
mag and effective radii larger than 170 pc. Their radial number density decreases exponentially with distance from the center of NGC 2784 until it flattens beyond a radius of 0.5 Mpc. We interpret the baseline density level to represent the background contamination and estimate that 22 of the 31 new candidates are dwarf members of the group. The candidate’s average color,
, and Sérsic structural parameters are consistent with those parameters for the dwarf populations of other groups. We find that the central population of dwarfs is redder and brighter than the rest of the population. The measured faint-end slope of the luminosity function,
, is steeper than that of the Local Group, but consistent with published results for other groups. Such comparisons are complicated by systematic differences among different studies, but will be simpler when the KMTNet survey, which will provide homogenous data for 15–20 groups, is completed.
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