Halide perovskites have recently been shown to exhibit excellent carrier transport properties. Density functional calculations are performed to study the electronic structure, dielectric properties, ...and defect properties of β-CH
3
NH
3
PbI
3
. The results show that Pb chemistry plays an important role in a wide range of material properties,
i.e.
, small effective masses, enhanced Born effective charges and lattice polarization, and the suppression of the formation of deep defect levels, all of which contribute to the exceptionally good carrier transport properties observed in CH
3
NH
3
PbI
3
. Defect calculations show that, among native point defects (including vacancies, interstitials, and antisites), only iodine vacancy is a low-energy deep trap and non-radiative recombination centre. Alloying iodide with chloride reduces the lattice constant of the iodide and significantly increases the formation energy of interstitial defects, which explains the observed substantial increase in carrier diffusion length in mixed halide CH
3
NH
3
PbI
2
Cl compared to that in CH
3
NH
3
PbI
3
.
Most anti-cancer drugs are derived from natural resources such as marine, microbial and botanical sources. Cutaneous malignant melanoma is the most aggressive form of skin cancer, with a high ...mortality rate. Various treatments for malignant melanoma are available, but due to the development of multi-drug resistance, current or emerging chemotherapies have a relatively low success rates. This emphasizes the importance of discovering new compounds that are both safe and effective against melanoma. In vitro testing of melanoma cell lines and murine melanoma models offers the opportunity for identifying mechanisms of action of plant derived compounds and extracts. Common anti-melanoma effects of natural compounds include potentiating apoptosis, inhibiting cell proliferation and inhibiting metastasis. There are different mechanisms and pathways responsible for anti-melanoma actions of medicinal compounds such as promotion of caspase activity, inhibition of angiogenesis and inhibition of the effects of tumor promoting proteins such as PI3-K, Bcl-2, STAT3 and MMPs. This review thus aims at providing an overview of anti-cancer compounds, derived from natural sources, that are currently used in cancer chemotherapies, or that have been reported to show anti-melanoma, or anti-skin cancer activities. Phytochemicals that are discussed in this review include flavonoids, carotenoids, terpenoids, vitamins, sulforaphane, some polyphenols and crude plant extracts.
Alloys with ultra-high strength and sufficient ductility are highly desired for modern engineering applications but difficult to develop. Here we report that, by a careful controlling alloy ...composition, thermomechanical process, and microstructural feature, a Co-Cr-Ni-based medium-entropy alloy (MEA) with a dual heterogeneous structure of both matrix and precipitates can be designed to provide an ultra-high tensile strength of 2.2 GPa and uniform elongation of 13% at ambient temperature, properties that are much improved over their counterparts without the heterogeneous structure. Electron microscopy characterizations reveal that the dual heterogeneous structures are composed of a heterogeneous matrix with both coarse grains (10∼30 μm) and ultra-fine grains (0.5∼2 μm), together with heterogeneous L1
-structured nanoprecipitates ranging from several to hundreds of nanometers. The heterogeneous L1
nanoprecipitates are fully coherent with the matrix, minimizing the elastic misfit strain of interfaces, relieving the stress concentration during deformation, and playing an active role in enhanced ductility.
With the rapid development of wireless communications, vehicular ad hoc networks (VANETs) have recently attracted great attention. Although IEEE 802.11p has been approved as the standard medium ...access control (MAC) protocol for vehicle-to-vehicle communications, its contention-based nature and inability to handle hidden-terminal problems may incur high packet collision probability under high-traffic-density situations. To overcome the shortcoming of IEEE 802.11p, time-division multiple-access (TDMA)-based protocols are proposed. However, packet collisions can still occur due to contention or multiple vehicles using the same slot while approaching each other, i.e., encounter collisions, particularly in two-way traffic roads. Some proposed remedying the encounter collisions for two-way traffic by partitioning a frame into two sets: one for the traffic in each direction. However, these proposed protocols are harder to adapt to the uneven traffic loads on both directions and cannot solve the problem of four-way intersections. In this paper, we propose a new TDMA protocol called prediction-based TDMA MAC (PTMAC) based on a novel way of predicting encounter collisions and effectively reducing the number of collisions. To the best of our knowledge, PTMAC is the first protocol that is designed for both two-way traffic and four-way intersections. It has shown that, based on this predictability, the encounter collisions can be greatly reduced in both two-way traffic and four-way intersections, regardless of the traffic loads on different road segments.
Development of efficient and durable oxygen evolution reaction (OER) catalysts has a direct impact on the water splitting efficiency and cost effectiveness. In this work, we report the successful ...synthesis of a new Ni(OH)
2
structure, strain-stabilized Ni(OH)
2
nanoribbons (NR-Ni(OH)
2
) two to three layers thick, with widths of 2-5 nm,
via
an electro-oxidation route. Conventional Ni(OH)
2
usually has negligible OER activity, while NR-Ni(OH)
2
shows high activity for the oxygen evolution reaction and an overpotential of 162 millivolts and furthermore exhibits long-term stability in alkaline electrolyte. The substantial reduction in the overpotential of NR-Ni(OH)
2
is due to its easier OOH* adsorption by the active four-coordinated Ni edge sites. The enhanced catalytic activity of NR-Ni(OH)
2
makes it an excellent candidate for industrial applications.
Development of efficient and durable oxygen evolution reaction (OER) catalysts has a direct impact on the water splitting efficiency and cost effectiveness.
Recently, piezoelectric thin films including zinc oxide (ZnO) and aluminium nitride (AlN) have found a broad range of lab-on-chip applications such as biosensing, particle/cell concentrating, ...sorting/patterning, pumping, mixing, nebulisation and jetting. Integrated acoustic wave sensing/microfluidic devices have been fabricated by depositing these piezoelectric films onto a number of substrates such as silicon, ceramics, diamond, quartz, glass, and more recently also polymer, metallic foils and bendable glass/silicon for making flexible devices. Such thin film acoustic wave devices have great potential for implementing integrated, disposable, or bendable/flexible lab-on-a-chip devices into various sensing and actuating applications. This paper discusses the recent development in engineering high performance piezoelectric thin films, and highlights the critical issues such as film deposition, MEMS processing techniques, control of deposition/processing parametres, film texture, doping, dispersion effects, film stress, multilayer design, electrode materials/designs and substrate selections. Finally, advances in using thin film devices for lab-on-chip applications are summarised and future development trends are identified.
Autophagy is a degradative process that recycles long-lived and faulty cellular components. It is linked to many diseases and is required for normal development. ULK1, a mammalian serine/threonine ...protein kinase, plays a key role in the initial stages of autophagy, though the exact molecular mechanism is unknown. Here we report identification of a novel protein complex containing ULK1 and two additional protein factors, FIP200 and ATG13, all of which are essential for starvation-induced autophagy. Both FIP200 and ATG13 are critical for correct localization of ULK1 to the pre-autophagosome and stability of ULK1 protein. Additionally, we demonstrate by using both cellular experiments and a de novo in vitro reconstituted reaction that FIP200 and ATG13 can enhance ULK1 kinase activity individually but both are required for maximal stimulation. Further, we show that ATG13 and ULK1 are phosphorylated by the mTOR pathway in a nutrient starvation-regulated manner, indicating that the ULK1·ATG13·FIP200 complex acts as a node for integrating incoming autophagy signals into autophagosome biogenesis.
Leptomeningeal metastases (LM) are more frequent in non-small-cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations. Due to limited access to leptomeningeal lesions, the ...purpose of this study was to explore the potential role of cerebrospinal fluid (CSF) as a source of liquid biopsy in patients with LM.
Primary tumor, CSF, and plasma in NSCLC with LM were tested by next-generation sequencing. In total, 45 patients with suspected LM underwent lumbar puncture, and those with EGFR mutations diagnosed with LM were enrolled.
A total of 28 patients were enrolled in this cohort; CSF and plasma were available in 26 patients, respectively. Driver genes were detected in 100% (26/26), 84.6% (22/26), and 73.1% (19/26) of samples comprising CSF cell-free DNA (cfDNA), CSF precipitates, and plasma, respectively; 92.3% (24/26) of patients had much higher allele fractions in CSF cfDNA than the other two media. Unique genetic profiles were captured in CSF cfDNA compared with those in plasma and primary tissue. Multiple copy number variations (CNVs) were mainly identified in CSF cfDNA, and MET copy number gain identified in 47.8% (11/23) of patients was the most frequent one, while other CNVs included ERBB2, KRAS, ALK, and MYC. Moreover, loss of heterozygosity (LOH) of TP53 was identified in 73.1% (19/26) CSF cfDNA, which was much higher than that in plasma (2/26, 7.7%; P<0.001). There was a trend towards a higher frequency of concomitant resistance mutations in patients with TP53 LOH than those without (70.6% versus 33.3%; P=0.162). EGFR T790M was identified in CSF cfDNA of 30.4% (7/23) of patients who experienced TKI progression.
CSF cfDNA could reveal the unique genetic profiles of LM and should be considered as the most representative liquid biopsy medium for LM in EGFR-mutant NSCLC.
Abstract
Formononetin is a naturally existing isoflavone, which can be found in the roots of
Astragalus membranaceus, Trifolium pratense, Glycyrrhiza glabra
, and
Pueraria lobata.
It was found to be ...associated with inhibition of cell proliferation and cell cycle progression, as well as induction of apoptosis in various cancer cell lines. However, the effect of formononetin on breast cancer cell metastasis remains unclear. In this study, we examined the effect of formononetin on the migration and invasion of breast cancer cells MDA-MB-231 and 4T1 in vitro and in vivo. Our data demonstrated that formononetin did not effectively inhibit the cell viability of MDA-MB-231 and 4T1 in 24 h with the concentration lower than 160 μmol/l. When treated with nontoxic concentration of formononetin, the migration and invasion of MDA-MB-231 and 4T1 cells were markedly suppressed by wound healing assay, chamber invasion assay, and in vivo mouse metastasis model. In vitro, formononetin reduced the expression of matrix metalloproteinase-2 (MMP-2), MMP-9 and increased the expression of tissue inhibitor of metalloproteinase-1 (TIMP-1) and TIMP-2. Furthermore, the immunofluorescence and immunoblotting assays indicated that formononetin was very effective in suppressing the phosphorylation of Akt and PI3K. Collectively, these results suggest that formononetin inhibited breast cancer cell migration and invasion by reducing the expression of MMP-2 and MMP-9 through the PI3K/AKT signaling pathway. These findings demonstrate a potentially new therapeutic strategy of formononetin as anti-invasive agent for breast cancer.
Layered Ti-Al metal composite (LMC) fabricated by hot-pressing and hot-rolling process displays higher ductility than that of both components. In this paper, a combination of digital image ...correlation (DIC) and X-ray tomography revealed that strain delocalization and constrained crack distribution are the origin of extraordinary tensile ductility. Strain delocalization was derived from the transfer of strain partitioning between Ti and Al layer, which relieved effectively the strain localization of LMC. Furthermore, the extensive cracks of LMC were restricted in the interface due to constraint effect. Layered architecture constrained the distribution of cracks and significantly relieved the strain localization. Meanwhile, the transfer of strain partitioning and constrained crack distribution were believed to inhibit the strain localization of Ti and change the deformation mechanisms of Ti. Our finding enriches current understanding about simultaneously improving the strength and ductility by structural design.
PDF
