Abstract
High-precision light curves were extracted from TESScut images. Together with APOGEE and LAMOST medium-resolution spectra, a joint study was made for six early K-type contact binary ...candidates selected unbiasedly with orbital periods around 0.268 day. It is found that all of them (RV CVn, EK Com, V384 Ser, V1038 Her, EH CVn, and CSS_J125403.7+503945) are W-subtype shallow contact systems, though with different mass ratios (1/
q
= 0.27–0.62). The effective temperature differences between the binary components are around a few hundred kelvins. The original definitions of the A and W subtypes were compared with the customarily used methods, which rely on the shape or photometric solutions of the light curves. The latter two methods are not always reliable; therefore, the radial velocity analysis is strongly recommended. Through a collection of all available K-type contact binaries with both photometric and spectroscopic measurements, it is found that almost all of them are W-subtype systems, except for a few objects that have nearly identical temperatures for binary components. This W-subtype phenomenon for K-type contact binaries should be further checked with more samples in the future. Finally, the physical parameters of the targets were determined with joint data analysis, and the multiplicity is discussed for these targets. Objects V384 Ser and RV CVn are confirmed to very likely be triple systems from comprehensive analysis, while V1038 Her is a candidate of a triple system based on photometric and spectroscopic solutions.
Side population (SP) cells within tumors are a small fraction of cancer cells with stem-like properties that can be identified by flow cytometry analysis based on their high ability to export certain ...compounds such as Hoechst 33342 and chemotherapeutic agents. The existence of stem-like SP cells in tumors is considered as a key factor contributing to drug resistance, and presents a major challenge in cancer treatment. Although it has been recognized for some time that tumor tissue niches may significantly affect cancer stem cells (CSCs), the role of key nutrients such as glucose in the microenvironment in affecting stem-like cancer cells and their metabolism largely remains elusive. Here we report that SP cells isolated from human cancer cells exhibit higher glycolytic activity compared to non-SP cells. Glucose in the culture environment exerts a profound effect on SP cells as evidenced by its ability to induce a significant increase in the percentage of SP cells in the overall cancer cell population, and glucose starvation causes a rapid depletion of SP cells. Mechanistically, glucose upregulates the SP fraction through ATP-mediated suppression of AMPK and activation of the Akt pathway, leading to elevated expression of the ATP-dependent efflux pump ABCG2. Importantly, inhibition of glycolysis by 3-BrOP significantly reduces SP cells in vitro and impairs their ability to form tumors in vivo. Our data suggest that glucose is an essential regulator of SP cells mediated by the Akt pathway, and targeting glycolysis may eliminate the drug-resistant SP cells with potentially significant benefits in cancer treatment.
To balance the utilization of rare earth (RE) resource and develop Ce-based permanent magnets with high performance/cost ratio, the role of La substitution in the melt-spun (Ce
1−
x
La
x
)
y
Fe
14
B ...(
x
= 0–0.4, and 0.5;
y
= 2–4) alloys has been investigated. It has been confirmed that the hard magnetic properties of Ce-based magnets can be effectively enhanced by partial substitution of La. The maximum (
BH
)
max
of (Ce,La)–Fe–B alloys can be obtained at a Ce:La atomic ratio of 7:3. The lattice parameters and Curie temperature of the hard magnetic (Ce/La)
2
Fe
14
B phase increase linearly with increasing La content. Three different alloy systems with
y
= 2, 2.5 and 3 show similar behavior of magnetic properties dependences on La. In the RE-rich compositions, La substitution for Ce can effectively inhibit the precipitation of the CeFe
2
phase. A solid solution, Ce(La) phase with a space group of Fm-3m, appears in the (Ce
0.7
La
0.3
)
y
Fe
14
B alloys with
y
≥ 3.5. A good combination of magnetic properties with
H
cj
= 345 kA/m,
J
5T
= 1.03 T,
J
r
= 0.60 T, and (
BH
)
max
= 6.3 MGOe is obtained in (Ce
0.7
La
0.3
)
2.5
Fe
14
B alloy. In addition, 30 at.% La substitution for Ce can significantly refine the grains, resulting in the enhancement of exchange coupling interaction. The present finding is beneficial for designing new and low-cost magnetic materials.
Ce substituted Nd
Fe
B (2:14:1)-type permanent magnets have shown increasing potential in the applications due to their high properties/cost ratio. However, the element segregation and phase ...separation in the Ce substituted magnets have not been fully understood yet. In this work, (Nd
Ce
)
Fe
Co
Al
B
alloys with high coercivities were prepared by copper mold casting. Based on detailed microstructure and composition analysis, the segregation of rare earth (RE) elements was observed in the as-cast alloys. Nd element prefers to enter into the 2:14:1 phase and the Ce element enter into the 1:2 phase. The existence of the 1:2 phase can promote the element segregation. The alloy shows an abnormal increase of coercivity from 641 kA/m for x = 0.2 to 863 kA/m for x = 0.3. This increase could be attributed to the phase separation of the 2:14:1 phase, which has been confirmed by the microstructural characterization. The present data provides useful information for exploring Ce-containing Nd-Fe-B magnets.
WUMa-type stars are contact systems where both cool components fill the critical Roche lobes and share a common convective envelope. Long and unbroken time-series photometry is expected to play an ...important role in their origin and activity. The newly discovered short-period WUMa-type star, CSTAR 038663, was monitored continuously by Chinese Small Telescope ARray (CSTAR) in Antarctica during the winters of 2008 and 2010. Both the shallow contact configuration and the extremely high mass ratio suggest that CSTAR 038663 is presently evolving into a contact system with little mass transfer. The formation and evolution is driven by the loss of angular momentum via magnetic braking, and the close-in companion star is expected to play an important role, removing angular momentum from the central eclipsing binary.
We propose and demonstrate a Fabry-Perot (F-P) optical fiber tip sensor for high-resolution refractive-index measurement fabricated by using 157-nm laser micromachining, for the first time to our ...knowledge. The sensor head consists of a short air F-P cavity near the tip of a single-mode fiber and the fiber tip. The external refractive index is determined according to the maximum fringe contrast of the interference fringes in the reflective spectrum of the sensor. Such a sensor can provide temperature-independent measurement of practically any refractive index larger than that of air and offers a refractive-index resolution of ~4 x 10(-5) in its linear operating range. The experimental data agree well with the theoretical results.
Low anisotropy field and low Curie temperature of Ce2Fe14B phase seriously restrict the application of Ce-Fe-B alloys. Most of the previous work suggest that REFe2 phase inevitably forms in the ...compositions with high Ce content. In this work, Si substitution for Fe is found to not only suppress the formation of CeFe2 phase, but also significantly improve the coercivity Hc and thermal stability of Ce17Fe78-xSixB6 (x = 0–3.0) alloys. All Si-doped alloys exhibit higher Hc and better thermal stability than Ce17Fe78B6 alloy. With increasing Si doping, a relatively high Hc = 525 kA/m is obtained in the Ce17Fe77.75Si0.25B6 alloy. An abnormal increase of Hc as well as almost unchanged Jr and (BH)max is observed in Ce17Fe78-xSixB6 (x > 1.5) alloys. The refined XRD results indicate that the volume fraction of CeFe2 phase can be dramatically reduced via a moderate content of Si doping. Hard magnetic grains are isolated by forming a structure with thin and continuous intermediate layer, consequently preventing the domain wall propagation. The Curie temperature of the main phase monotonically increases from 424 K for x = 0–445 K for x = 3.0, resulting in improved thermal stability. The highest Hc of 530 kA/m, the lowest temperature coefficients (|β| = 0.551%/°C and |α| = 0.368%/°C), and an acceptable Jr = 0.44 T are obtained in Ce17Fe78-xSixB6 (x = 3.0) alloy. The nucleation and pinning are both responsible for the coercivity mechanism of Ce17Fe75Si3B6 alloy, which should be the reason for its high coercivity.
•The formation of undesired CeFe2 phase is suppressed by Si doping.•Si doping increases Curie temperature and improves thermal stability.•A structure with thin and continuous grain boundary phase is formed by Si doping.•Increased Hc and almost unchanged Jr and (BH)max can be obtained in Si doped alloys.•A domain wall pinning effect is observed in Ce17Fe75Si3B6 alloy.
•The formation of La2Fe14B phase can be enhanced by Nd substitution.•≥30% Nd is needed to achieve good hard magnetic properties in La-Fe-B alloy.•(La0.7Nd0.3)16Fe78B6 melt-spun alloy exhibits ...relatively high magnetic properties.•Thermal stability of La-Fe-B alloy are well improved by Nd-substituted.
Aiming at promoting the formation of hard magnetic 2:14:1 phase in La-Fe-B alloys, the effects of Nd substitution on the melt-spun nanocrystalline (La1-xNdx)yFe94-yB6 alloys (x = 0–0.5; y = 12–16) have been investigated. No hard magnetic phase was formed in the (La1-xNdx)16Fe78B6 alloys with x < 0.2. A soft magnetic phase (La,Nd)2Fe23B3 with Curie temperature of 649 K was observed in the x = 0.2 alloy and it disappeared as x increased to 0.3. 30% and above Nd substitution can dramatically enhance the formation of 2:14:1 phase and the magnetic properties of La-based permanent magnets. Three different alloy systems (y = 16, 14 and 12) show similar behavior of magnetic properties dependences on Nd substitution. (La0.7Nd0.3)16Fe78B6 alloy with mean grain size 10–20 nm exhibits high remanent magnetization, maximum energy product and intrinsic coercivity up to 0.71 T, 10.0 MGOe and 562 kA/m, respectively, indicating it is possible to achieve excellent magnetic properties in La-based rare earth permanent magnets. The present work provides a good understanding on the fundamental magnetism of La-based magnets and the potential to develop low cost rare earth permanent magnets.
Gallium (III) metal-organic complexes have been shown to have the ability to inhibit tumor growth, but the poor water solubility of many of the complexes precludes further application. The use of ...materials with high biocompatibility as drug delivery carriers for metal-organic complexes to enhance the bioavailability of the drug is a feasible approach.
Here, we modified the ligands of gallium 8-hydroxyquinolinate complex with good clinical anticancer activity by replacing the 8-hydroxyquinoline ligands with 5-bromo-8-hydroxyquinoline (HBrQ), and the resulting Ga(III) + HBrQ complex had poor water solubility. Two biocompatible materials, bovine serum albumin (BSA) and graphene oxide (GO), were used to synthesize the corresponding Ga(III) + HBrQ complex nanoparticles (NPs) BSA/Ga/HBrQ NPs and GO/Ga/HBrQ NPs in different ways to enhance the drug delivery of the metal complex.
Both of BSA/Ga/HBrQ NPs and GO/Ga/HBrQ NPs can maintain stable existence in different solution states. In vitro cytotoxicity test showed that two nanomedicines had excellent anti-proliferation effect on HCT116 cells, which shown higher level of intracellular ROS and apoptosis ratio than that of cisplatin and oxaliplatin. In addition, the superior emissive properties of BSA/Ga/HBrQ NPs and GO/Ga/HBrQ NPs allow their use for in vivo imaging showing highly effective therapy in HCT116 tumor-bearing mouse models.
The use of biocompatible materials for the preparation of NPs against poorly biocompatible metal-organic complexes to construct drug delivery systems is a promising strategy that can further improve drug delivery and therapeutic efficacy.
Although a commonly applied measure across the United States and Europe for alleviating the negative impacts of urbanization on the hydrological cycle, low impact development (LID) has not been ...widely used in highly urbanized areas, especially in rapidly urbanizing cities in developing countries like China. In this paper, given five LID practices including Bio-Retention, Infiltration Trench, Porous Pavement, Rain Barrels, and Green Swale, an analysis on LID for highly urbanized areas' waterlogging control is demonstrated using the example of Caohejing in Shanghai, China. Design storm events and storm water management models are employed to simulate the total waterlogging volume reduction, peak flow rate reduction and runoff coefficient reduction of different scenarios. Cost-effectiveness is calculated for the five practices. The aftermath shows that LID practices can have significant effects on storm water management in a highly urbanized area, and the comparative results reveal that Rain Barrels and Infiltration Trench are the two most suitable cost-effective measures for the study area.
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