This article establishes a new multiunmanned aerial vehicle (multi-UAV)-enabled mobile edge computing (MEC) system, where a number of unmanned aerial vehicles (UAVs) are deployed as flying edge ...clouds for large-scale mobile users. In this system, we need to optimize the deployment of UAVs, by considering their number and locations. At the same time, to provide good services for all mobile users, it is necessary to optimize task scheduling. Specifically, for each mobile user, we need to determine whether its task is executed locally or on a UAV (i.e., offloading decision), and how many resources should be allocated (i.e., resource allocation). This article presents a two-layer optimization method for jointly optimizing the deployment of UAVs and task scheduling, with the aim of minimizing system energy consumption. By analyzing this system, we obtain the following property: the number of UAVs should be as small as possible under the condition that all tasks can be completed. Based on this property, in the upper layer, we propose a differential evolution algorithm with an elimination operator to optimize the deployment of UAVs, in which each individual represents a UAV's location and the entire population represents an entire deployment of UAVs. During the evolution, we first determine the maximum number of UAVs. Subsequently, the elimination operator gradually reduces the number of UAVs until at least one task cannot be executed under delay constraints. This process achieves an adaptive adjustment of the number of UAVs. In the lower layer, based on the given deployment of UAVs, we transform the task scheduling into a 0-1 integer programming problem. Due to the large-scale characteristic of this 0-1 integer programming problem, we propose an efficient greedy algorithm to obtain the near-optimal solution with much less time. The effectiveness of the proposed two-layer optimization method and the established multi-UAV-enabled MEC system is demonstrated on ten instances with up to 1000 mobile users.
Ultralong cycle life, high energy, and power density rechargeable lithium‐ion batteries are crucial to the ever‐increasing large‐scale electric energy storage for renewable energy and sustainable ...road transport. However, the commercial graphite anode cannot perform this challenging task due to its low theoretical capacity and poor rate‐capability performance. Metal oxides hold much higher capacity but still are plagued by low rate capability and serious capacity degradation. Here, a novel strategy is developed to prepare binder‐free and mechanically robust CoO/graphene electrodes, wherein homogenous and full coating of β‐Co(OH)2 nanosheets on graphene, through a novel electrostatic induced spread growth method, plays a key role. The combined advantages of large 2D surface and moderate inflexibility of the as‐obtained β‐Co(OH)2/graphene hybrid enables its easy coating on Cu foil by a simple layer‐by‐layer stacking process. Devices made with these electrodes exhibit high rate capability over a temperature range from 0 to 55 °C and, most importantly, maintain excellent cycle stability up to 5000 cycles even at a high current density.
Homogeneous β‐Co(OH)2 on graphene is synthesized using a simple and effective electrostatic induced spread growth method, which ensures the facile fabrication of a binder‐free and mechanically robust CoO/graphene electrode by means of a layer‐by‐layer stacking process. When employed as an anode in Li‐ion batteries, a high rate capability and excellent cycle stability up to 5000 cycles are successfully obtained.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Histone lysine specific demethylase 1 (LSD1) was reported to be overexpressed in several human cancers and recognized as a promising anticancer drug target. In the current study, we designed and ...synthesized a novel series of pyrimidine–thiourea hybrids and evaluated their potential LSD1 inhibitory effect. One of the compounds, 6b, containing a terminal alkyne appendage, was shown to be the most potent and selective LSD1 inhibitor in vitro and exhibited strong cytotoxicity against LSD1 overexpressed gastric cancer cells. Compound 6b also showed marked inhibition of cell migration and invasion as well as significant in vivo tumor suppressing and antimetastasis role, without significant side effects by oral administration. Our findings indicate that the pyrimidine–thiourea-based LSD1 inactivator may serve as a leading compound targeting LSD1 overexpressed cancers.
The oxidized 1‐palmitoyl‐2‐arachidonoyl‐sn‐glycero‐3‐phosphocholine (ox‐PAPC) products in human high‐density lipoproteins (HDLs) were investigated by low‐flow capillary electrophoresis‐mass ...spectrometry (low‐flow CE‐MS). To accelerate the optimization, native PAPC (n‐PAPC) standard was first analyzed by a commercial CE instrument with a photodiode array detector. The optimal separation buffer contained 60% (v/v) acetonitrile, 40% (v/v) methanol, 20 mM ammonium acetate, 0.5% (v/v) formic acid, and 0.1% (v/v) water. The selected separation voltage and capillary temperature were 20 kV and 23°C. The optimal CE separation buffer was then used for the low‐flow CE‐MS analysis. The selected MS conditions contained heated capillary temperature (250°C), capillary voltage (10 V), and injection time (1 s). No sheath gas was used for MS. The linear range for n‐PAPC was 2.5–100.0 µg/mL. The coefficient of determination (R2) was 0.9918. The concentration limit of detection was 1.52 µg/mL, and the concentration limit of quantitation was 4.60 µg/mL. The optimal low‐flow CE‐MS method showed good repeatability and sensitivity. The ox‐PAPC products in human HDLs were determined based on the in vitro ox‐PAPC products of n‐PAPC standard. Twenty‐one ox‐PAPC products have been analyzed in human HDLs. Uremic patients showed significantly higher levels of 15 ox‐PAPC products than healthy subjects.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The improved ionic conductivity (1.64 × 10–4 S cm–1 at room temperature) and excellent electrochemical stability of nanoporous β-Li3PS4 make it one of the promising candidates for rechargeable ...all-solid-state lithium-ion battery electrolytes. Here, elastic properties, defect thermodynamics, phase diagram, and Li+ migration mechanism of Li3PS4 (both γ and β phases) are examined via the first-principles calculations. Results indicate that both γ- and β-Li3PS4 phases are ductile while γ-Li3PS4 is harder under volume change and shear stress than β-Li3PS4. The electrochemical window of Li3PS4 ranges from 0.6 to 3.7 V, and thus the experimentally excellent stability (>5 V) is proposed due to the passivation phenomenon. The dominant diffusion carrier type in Li3PS4 is identified over its electrochemical window. In γ-Li3PS4 the direct-hopping of Lii + along the 001 is energetically more favorable than other diffusion processes, whereas in β-Li3PS4 the knock-off diffusion of Lii + along the 010 has the lowest migration barrier. The ionic conductivity is evaluated from the concentration and the mobility calculations using the Nernst–Einstein relationship and compared with the available experimental results. According to our calculated results, the Li+ prefers to transport along the 010 direction. It is suggested that the enhanced ionic conductivity in nanostructured β-Li3PS4 is due to the larger possibility of contiguous (010) planes provided by larger nanoporous β-Li3PS4 particles. By a series of motivated and closely linked calculations, we try to provide a portable method, by which researchers could gain insights into the physicochemical properties of solid electrolyte.
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IJS, KILJ, NUK, PNG, UL, UM
Lysine specific demethylase 1 (LSD1), the first identified histone demethylase, plays an important role in epigenetic regulation of gene activation and repression. The up-regulated LSD1’s expression ...has been reported in several malignant tumors. In the current study, we designed and synthesized five series of 1,2,3-triazole–dithiocarbamate hybrids and screened their inhibitory activity toward LSD1. We found that some of these compounds, especially compound 26, exhibited the most specific and robust inhibition of LSD1. Interestingly, compound 26 also showed potent and selective cytotoxicity against LSD1 overexpressing gastric cancer cell lines MGC-803 and HGC-27, as well as marked inhibition of cell migration and invasion, compared to 2-PCPA. Furthermore, compound 26 effectively reduced the tumor growth bared by human gastric cancer cells in vivo with no signs of adverse side effects. These findings suggested that compound 26 deserves further investigation as a lead compound in the treatment of LSD1 overexpressing gastric cancer.
In heart failure (HF) patients with reduced ejection fraction, LIPCAR, a long noncoding RNA is elevated and is associated with left ventricular remodeling and poor prognosis. We studied the role of ...LIPCAR in patients with HF post-acute myocardial infarction (AMI) to find biomarkers for early detection of HF. We conducted a study of 127 patients with AMI, of which 59 were patients with HF post-AMI. LIPCAR levels were higher in HF patients post-AMI than patients without HF, and LIPCAR had a high predictive value for diagnosis of HF, which was estimated by receiver operating characteristic curves (AUC: 0.985). The results indicate that LIPCAR may be a marker of early HF after AMI.
To identify superalkali-alkaline earthide ion pairs, it's theoretically shown that, as a novel class of excess electron superalkali compounds, both chair and boat forms of (AM-HMHC)-AM′ (AM = Li, Na, ...and K; AM′ = Be, Mg, and Ca; HMHC = 1,4,7,10,13,16-hexamethyl-1,4,7,10,13,16-hexaazacyclooctadecane) are good candidates. An attractive superalkali-alkaline earthide ion pair in
δ
+
(AM-HMHC)-AM′
δ
−
is firstly exhibited, which possesses alkaline-earthide characteristics and nonlinear optical response superior to similar M
+
(calix4pyrrole)M′
−
(M = Li, Na, and K; M′ = Be, Mg, and Ca) with high stability. The electronic and vibrational second order hyperpolarizabilities and the frequency-dependent first hyperpolarizabilities of
δ
+
(AM-HMHC)-AM′
δ
−
are presented. For each pair of (AM-HMHC)-AM′, the boat conformation is preferred to its chair one in the case of Hyper-Rayleigh scattering response (
β
HRS
). These alkaline earthides suggest prominently high
β
HRS
up to 2.59 × 10
4
a.u. (boat forms of
δ
+
(Na-HMHC)-Ca
δ
−
). We expect that this work will inspire the preparation and characterization of these new alkaline earthides as high-performance NLO materials.
To identify superalkali-alkaline earthide ion pairs, a novel class of excess electron superalkali compounds was theoretically constructed; both chair and boat (AM-HMHC)-AM′ (AM = Li, Na, K; AM′ = Be, Mg, Ca) show large NLO responses and excellent electronic stabilities and alkalide characteristics.
C
3
N has attracted much attention as an anode material for lithium-ion (Li-ion) batteries, owing to its excellent mechanical and electronic properties. However, its weak Li adsorption strength and ...mobility have limited its further application. Phosphorene (P) exhibits a high bonding strength with Li and excellent Li-ion mobility, but low stiffness. Thus, we propose that constructing a C
3
N/P hybrid material will not only negate the deficiency of C
3
N but also result in a new high performance electrode material. A C
3
N/P heterostructure is constructed and studied by first-principles calculations. This heterostructure exhibits an excellent stiffness (Young's modulus is 448.32 N m
−1
), which is even better than that of graphene. The bonding strength of Li inserted into the intralayer of the C
3
N/P heterostructure (1.78–2.02 eV) is much higher than that in pristine monolayer C
3
N (0.32 eV) and phosphorene (1.67 eV). Moreover, the C
3
N/P heterostructure shows a high capacity of 468.34 mA h g
−1
, and better conductivities of electricity and ions than pristine monolayer C
3
N. The excellent mechanical properties, high capacity, good conductivities of electrons and ions and moderately high bonding energy indicate that the C
3
N/P heterostructure is a promising anode material for lithium-ion batteries.
To combine both electride and alkalide characteristics in one molecular switch, it is shown herein that the phenalenyl radical and the M
3
ring (M
3
-PHY, M = Li, Na, and K) stacked with parallel and ...vertical geometries are good candidates. The former geometry is the superalkali electride e
−
M
3
+
-PHY while the latter geometry is the superalkalide M
δ
−
-M
2
(1-
δ
)+
-PHY
−
. The superalkalide M
δ
−
-M
2
(1−
δ
)+
-PHY
−
may isomerize to the superalkali electride e
−
M
3
+
-PHY (M = Li, Na, and K) using suitable long-wavelength irradiation, while the latter may isomerize to the former with suitable short-wavelength irradiation. Also, applying suitable oriented external electric fields can drive the superalkalide M
δ
−
M
2
(1−
δ
)+
-PHY
−
to change into the superalkali electride e
−
M
3
+
-PHY (M = Li, Na, and K). The differences in the static and dynamic first hyperpolarizability (
β
0
) values between them were also studied.
The superalkali electride e
−
Li
3
+
-PHY and superalkalide Li
δ
−
-Li
2
(1-
δ
)−
-PHY
−
show a good switchable effect.
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