Operating fuel cells in alkaline environments permits the use of platinum-group-metal-free (PGM-free) catalysts and inexpensive bipolar plates, leading to significant cost reduction. Of the PGM-free ...catalysts explored, however, only a few nickel-based materials are active for catalyzing the hydrogen oxidation reaction (HOR) in alkali; moreover, these catalysts deactivate rapidly at high anode potentials owing to nickel hydroxide formation. Here we describe that a nickel-tungsten-copper (Ni
WCu
) ternary alloy showing HOR activity rivals Pt/C benchmark in alkaline electrolyte. Importantly, we achieved a high anode potential up to 0.3 V versus reversible hydrogen electrode on this catalyst with good operational stability over 20 h. The catalyst also displays excellent CO-tolerant ability that Pt/C catalyst lacks. Experimental and theoretical studies uncover that nickel, tungsten, and copper play in synergy to create a favorable alloying surface for optimized hydrogen and hydroxyl bindings, as well as for the improved oxidation resistance, which result in the HOR enhancement.
The basic principle of quantum mechanics1 guarantees the unconditional security of quantum key distribution (QKD)2–6 at the cost of forbidding the amplification of a quantum state. As a result, and ...despite remarkable progress in worldwide metropolitan QKD networks7,8 over the past decades, a long-haul fibre QKD network without a trusted relay has not yet been achieved. Here, through the sending-or-not-sending protocol9, we achieve twin-field QKD10 and distribute secure keys without any trusted repeater over a 511 km long-haul fibre trunk that links two distant metropolitan areas. The fibre trunk contains 12 fibres in the cable, three of which are used for the quantum channel, optical synchronization and frequency locking, respectively. The remaining nine are used for classical fibre communication. Our secure key rate is around three orders of magnitude greater than that expected if the previous QKD field-test system was applied over the same length. Efficient quantum-state transmission and stable single-photon interference over such a long-haul deployed fibre pave the way to large-scale fibre quantum networks.A field test of twin-field quantum key distribution was implemented through a 511 km optical fibre. To this end, precise wavelength control of remote independent laser sources and fast time- and phase-compensation systems are developed.
Platinum on carbon (Pt/C) catalyst is commercially adopted in fuel cells but it undergoes formidable active‐site poisoning by carbon monoxide (CO). In particular, given the sluggish kinetics of ...hydrogen oxidation reaction (HOR) in anion‐exchange membrane fuel cell (AEMFC), the issues of Pt poisoning and slow rate would combine mutually, notably worsening the device performances. Here we overcome these challenges through incorporating cobalt (Co) into molybdenum‐nickel alloy (MoNi4), termed Co‐MoNi4, which not only shows superior HOR activity over the Pt/C catalyst in alkali, but more intriguingly exhibits excellent CO tolerance with only small activity decay after 10 000 cycles in the presence of 500 parts per million (ppm) CO. When feeding with CO (250 ppm)/H2, the AEMFC assembled by this catalyst yields a peak power density of 394 mW cm−2, far exceeding the Pt/C catalyst. Experimental and computational studies reveal that weakened CO chemisorption originates from the electron‐deficient Ni sites after Co incorporation that suppresses d→CO 2π* back‐donation.
Incorporating Co into MoNi4 nanocatalyst can suppress the d→CO 2π* back donation, leading to excellent CO tolerance. When feeding with CO (250 ppm)/H2, the fuel cell assembled by this catalyst yields a peak power density of 394 mW cm−2, exceeding that of 209 mW cm−2 for the Pt/C catalyst.
Chemoresistance has been an obstacle in the further improvement of 5‐year survival rates of osteosarcoma (OS) patients, but the underlying mechanism of chemo‐resistance remains unclear. A ...comprehensive analysis of mRNAs and noncoding RNAs related to OS chemo‐resistance could help solve this problem. In the current study, we first identified that fibronectin‐1 (FN1), screened by microarray analysis in three paired chemo‐resistant and chemo‐sensitive OS cell lines, was significantly upregulated in the chemo‐resistant OS cell lines and tissues and was related to unfavourable prognosis. Further functional assays revealed that FN1 inhibition greatly increased the sensitivity of OS cells to doxorubicin in vitro and in vivo, whereas FN1 overexpression had the opposite effect. Moreover, mechanistic investigation demonstrated, by a series of assays that included luciferase reporter gene, RNA immunoprecipitation, RNA pull‐down and rescue assays, that FN1 expression was regulated by the oncogenic long noncoding RNA (lncRNA) OIP5‐AS1 through sponging miR‐200b‐3p. Thus, these results indicated the role and potential application of the lncRNA OIP5‐AS1/miR‐200b‐3p/FN1 regulatory pathway as a promising target in treatment of OS chemo‐resistance.
First report about expression, function and potential clinical significance of fibronectin‐1 (FN1), miR‐200b‐3p, lncRNA OIP5‐AS1 in osteosarcoma (OS) doxorubicin resistance; Regulatory mechanism of FN1 expression was identified and lncRNA OIP5‐AS1/miR‐200b‐3p/FN1 regulatory pathway was first constructed in OS doxorubicin resistance.
Measurement-device-independent quantum key distribution (MDI-QKD), based on two-photon interference, is immune to all attacks against the detection system and allows a QKD network with untrusted ...relays. Since the MDI-QKD protocol was proposed, fiber-based implementations aimed at longer distance, higher key rates, and network verification have been rapidly developed. However, owing to the effect of atmospheric turbulence, MDI-QKD over a free-space channel remains experimentally challenging. Herein, by developing a robust adaptive optics system, high-precision time synchronization and frequency locking between independent photon sources located far apart, we realized the first free-space MDI-QKD over a 19.2-km urban atmospheric channel, which well exceeds the effective atmospheric thickness. Our experiment takes the first step toward satellite-based MDI-QKD. Moreover, the technology developed herein opens the way to quantum experiments in free space involving long-distance interference of independent single photons.
Strong adsorption and catalysis for lithium polysulfides (LiPSs) are critical toward the electrochemical stability of Li‐S batteries. Herein, a hollow sandwiched nanoparticle is put forward to ...enhance the adsorption‐catalysis‐conversion dynamic of sulfur species. The outer ultrathin Ni(OH)2 nanosheets not only confine LiPSs via both physical encapsulation and chemical adsorption, but also promote redox kinetics and accelerate the conversion of sulfur species, which is revealed by experiments and theoretical calculations. Meanwhile, the inner hollow polyaniline soft core provides a strong chemical bonding to LiPSs after vulcanization, which can chemically adsorpt LiPSs, and synergistically confine the shuttle effect. Moreover, the Ni(OH)2 nanosheets with a large specific area can enhance the wettability of electrolyte, and the flexible hollow sandwiched structure can accommodate the volume expansion, promoting sulfur utilization and structural stability. The obtained cathode exhibits excellent electrochemical performance with an initial discharge capacity of 1173 mAh g–1 and a small capacity decay of 0.08% per cycle even after 500 cycles at 0.2 C, among the best results of Ni(OH)2‐based materials for Li–S batteries. It is believed that the combination of adsorption‐catalysis‐conversion will shed a light on the development of cathode materials for stable Li–S batteries.
A sandwiched Ni(OH)2@S@P cathode is designed for stable Li–S batteries. The outer ultrathin Ni(OH)2 nanosheets enhance conversion kinetics of sulfur species, and endows a robust physical encapsulation and chemical adsorption for lithium polysulfides (LiPSs). The inner hollow polyaniline core provides a strong chemical bonding to LiPSs after vulcanization, synergistically inhibiting the LiPSs diffusion. The hollow/flexible structure accommodates volume expansion and improves sulfur utilization.
To identify prognostic factors for complete anatomical success (CAS) under different axial length (AL) conditions after vitrectomy plus internal limiting membrane (ILM) peeling for retinal detachment ...associated with macular hole (MHRD).
This retrospective study included 243 patients (251 eyes) with MHRD who underwent primary vitrectomy plus ILM peeling. Multivariate logistic regression explored prognostic factors for CAS in AL <30 mm and ≥ 30 mm groups.
Overall, 113 eyes (45.0% of 251) exhibited complete CAS after initial surgery. Eyes with CAS had greater best-corrected visual acuity improvement than eyes without CAS (p < 0.001). CAS was more common in eyes with AL < 30 mm (50.3% of 155) than in eyes with AL ≥ 30 mm (36.5%, 35/96; p = 0.032). In the AL < 30 mm group, CAS was associated with ILM insertion (odds ratio OR, 2.824, 95% confidence interval CI, 1.189-6.710; p = 0.019), silicone oil (SO)/perfluoropropane (C3F8) tamponade (SO: OR, 0.408, 95% CI, 0.191-0.873; C3F8: OR, 2.448, 95% CI, 1.145-5.234; p = 0.021) and staphyloma (OR, 0.318, 95% CI, 0.143-0.707; p = 0.005). In the AL ≥30 mm group, CAS was associated with ILM insertion (OR, 11.621, 95% CI, 2.557-52.813; p = 0.001), SO /C3F8 tamponade (SO: OR, 5.305, 95% CI, 1.206-23.334; C3F8: OR, 0.188, 95% CI, 0.043-0.829; p = 0.027) and age (OR, 0.928, 95% CI, 0.876-0.983; p = 0.011).
Vitrectomy plus ILM peeling can effectively treat MHRD but has limited efficacy in eyes with AL ≥ 30 mm. ILM insertion was associated with more frequent CAS at any AL. C3F8 tamponade yielded better outcomes with AL < 30 mm; SO tamponade yielded better outcomes with AL ≥ 30 mm.
More and more evidence indicates that circular RNAs (circRNAs) have important roles in several diseases, especially in cancers. However, their involvement remains to be investigated in breast cancer. ...Through screening circRNA profile, we identified 235 differentially expressed circRNAs in breast cancer. Subsequently, we explored the clinical significance of two circTADA2As in a large cohort of triple-negative breast cancer (TNBC), and performed functional analysis of circTADA2A-E6 in vitro and in vivo to support clinical findings. Finally, we evaluated the effect of circTADA2A-E6 on miR-203a-3p and its target gene SOCS3. We detected two circRNAs, circTADA2A-E6 and circTADA2A-E5/E6, which were among the top five differentially expressed circRNAs in breast cancer. They were consistently and significantly decreased in a large cohort of breast cancer patients, and their downregulation was associated with poor patient survival for TNBC. Especially, circTADA2A-E6 suppressed in vitro cell proliferation, migration, invasion, and clonogenicity and possessed tumor-suppressor capability. circTADA2A-E6 preferentially acted as a miR-203a-3p sponge to restore the expression of miRNA target gene SOCS3, resulting in a less aggressive oncogenic phenotype. circTADA2As as promising prognostic biomarkers in TNBC patients, and therapeutic targeting of circTADA2As/miRNA/mRNA network may be a potential strategy for the treatment of breast cancer.
China's Chang'E-3 (CE-3) spacecraft touched down on the northern Mare Imbrium of the lunar nearside (340.49°E, 44.12°N), a region not directly sampled before. We report preliminary results with data ...from the CE-3 lander descent camera and from the Yutu rover's camera and penetrating radar. After the landing at a young 450-meter crater rim, the Yutu rover drove 114 meters on the ejecta blanket and photographed the rough surface and the excavated boulders. The boulder contains a substantial amount of crystals, which are most likely plagioclase and/or other mafic silicate mineral aggregates similar to terrestrial dolerite. The Lunar Penetrating Radar detection and integrated geological interpretation have identified more than nine subsurface layers, suggesting that this region has experienced complex geological processes since the Imbrian and is compositionally distinct from the Apollo and Luna landing sites.
Many platinum group metal-free inorganic catalysts have demonstrated high intrinsic activity for diverse important electrode reactions, but their practical use often suffers from undesirable ...structural degradation and hence poor stability, especially in acidic media. We report here an alkali-heating synthesis to achieve phase-mixed cobalt diselenide material with nearly homogeneous distribution of cubic and orthorhombic phases. Using water electroreduction as a model reaction, we observe that the phase-mixed cobalt diselenide reaches the current density of 10 milliamperes per square centimeter at overpotential of mere 124 millivolts in acidic electrolyte. The catalyst shows no sign of deactivation after more than 400 h of continuous operation and the polarization curve is well retained after 50,000 potential cycles. Experimental and computational investigations uncover a boosted covalency between Co and Se atoms resulting from the phase mixture, which substantially enhances the lattice robustness and thereby the material stability. The findings provide promising design strategy for long-lived catalysts in acid through crystal phase engineering.
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