Iron is the most important component of the cores of terrestrial planets, and iron sulfide (FeS) is one of the preferred candidates present in these cores. FeS is also ubiquitous in Earth’s crust, ...peridotites, and extraterrestrial samples. Knowledge of the phase stability of FeS and Fe isotope fractionation between FeS phases and mantle silicates is of great importance for understanding the interior of the Earth and terrestrial planets. In this study, first-principles methods were used to study the pressure-dependent phase stability of FeS and equilibrium Fe isotope fractionation in FeS, hexagonal close-packed (hcp) Fe, and mantle silicates at the pressure of Earth’s interior. FeS underwent four phase transitions at 0 K. The first is the transition from FeS I to FeS II at 2.8 GPa, the second from FeS II to FeS III at 7.5 GPa, the third from FeS III to FeS VI at 74.2 GPa, and the fourth from FeS VI to FeS VII at 122.2 GPa. Apart from the fact that the transition from FeS I to FeS II causes negligible Fe isotope fractionation, other phase transitions can cause measurable Fe isotope fractionation at corresponding pressures along the geotherm. Fe isotopes exhibit measurable fractionation between FeS and mantle silicates under mantle pressure–temperature conditions. Each phase was more enriched in heavy Fe with increasing depth in the pressure range of 7.5–90 GPa. If the silicate mantle is enriched in heavy Fe relative to the core or Fe has negligible isotope fractionation between them under the core-mantle boundary (CMB) conditions of the Earth, the Fe2+/(Fe2++Mg) in (Fe2+, Mg)SiO3 post-perovskite is less than 50%. At the temperature–pressure conditions of Earth’s core, equilibrium Fe isotope fractionation between hcp Fe and FeS VII can be neglected. FeS III is more likely to exist in the Martian core relative to FeS VI.
UIO-66 and UIO-66-NH2 were synthesized by a solvent thermal method, and their textures were characterized. The adsorption selectivity, kinetics, isotherms, and mechanism of the two MOFs in a single ...solute system for phenol, 4-nitrophenol, 2,4-dinitrophenol, and 2,4,6-trinitrophenol were studied. At pH 4.0, the two MOFs exhibited a greater adsorption capacity for 2,4-dinitrophenol than for other nitrophenols; however, at lower substrate concentrations (C 0 < 100 mg/L), the adsorption capacity of UiO-66-NH2 for 2,4-dinitrophenol was greater than that of UiO-66. The study of the adsorption mechanism showed that the electrostatic attraction is the main way in which UIO-66 and UiO-66-NH2 adsorb nitrophenols. Moreover, there was π-electron accumulation at a certain angle between the benzene ring of the adsorbents and the benzene ring of nitrophenols, whereas UiO-66-NH2 could also combine the nitrophenols through the hydrogen bonds originating from the amino groups. The fitting results of adsorption data showed the pseudo-second-order model, and the Langmuir isotherm model could well represent the adsorption kinetics and isotherm adsorption processes, respectively. In the mixed solution consisting of 4-nitrophenol, 2,4-dinitrophenol, and 2,4,6-trinitrophenol, the competitive adsorption ability of UIO-66 and UIO-66-NH2 for 2,4-dinitrophenol were greater than for the other two nitrophenols, showing that the size of the substrate and the surface area of the adsorbent were also factors that affect the adsorption efficiency.
Power is an important part of the energy industry, relating to national economy and people’s livelihood, and it is of great significance to ensure the security and stability in operation of power ...transmission and distribution system. Based on Wireless Sensor Network technology (WSN) and combined with the monitoring and operating requirements of power transmission and distribution system, this paper puts forward an application system for monitoring, inspection, security, and interactive service of layered power transmission and distribution system. Furthermore, this paper demonstrates the system verification projects in Wuxi, Jiangsu Province and Lianxiangyuan Community in Beijing, which have been widely used nationwide.
In this paper, a new family of proportionate normalized least mean square (PNLMS) adaptive algorithms that improve the performance of identifying block-sparse systems is proposed. The main proposed ...algorithm, called block-sparse PNLMS (BS-PNLMS), is based on the optimization of a mixed l2,1 norm of the adaptive filter's coefficients. It is demonstrated that both the NLMS and the traditional PNLMS are special cases of BS-PNLMS. Meanwhile, a block-sparse improved PNLMS (BS-IPNLMS) is also derived for both sparse and dispersive impulse responses. Simulation results demonstrate that the proposed BS-PNLMS and BS-IPNLMS algorithms outperformed the NLMS, PNLMS and IPNLMS algorithms with only a modest increase in computational complexity.
A significant characteristic of advanced gastric cancer (GC) is immune suppression, which can promote the progression of GC. Interleukin 35 (IL-35) is an immune-suppressing cytokine, and it is ...generally recognized that this cytokine is secreted by regulatory T (Treg) cells. Recently, studies have found that IL-35 can also be produced by B cells in mice. However, scientific studies reporting that IL-35 is secreted by B cells in humans, specifically in cancer patients, are very rare.Blood samples were collected from 30 healthy controls (HCs) and 50 untreated GC patients, and IL-35-producing B cells in the peripheral blood were investigated. Moreover, Treg cells (CD4CD25CD127), myeloid-derived suppressor cells (MDSCs) (CD14HLA-DR) and other lymphocyte subsets (CD3, CD4, CD8 T cells, activated and memory CD4 T cells, activated CD8 T cells, CD14 monocytes, and IL-10-producing B cells) were also examined.IL-35-producing B cells were significantly upregulated in patients with advanced GC. Furthermore, the frequency of IL-35-producing B cells was positively correlated with the frequencies of Treg cells (CD4CD25CD127), MDSCs (CD14HLA-DR), IL-10-producing B cells, and CD14 monocytes in these GC patients.In summary, the frequency of IL-35-producing B cells is significantly elevated in advanced GC; this outcome implies that this group of B cells may participate in GC progression.
The primary cause of heart failure is the loss of cardiomyocytes in the diseased adult heart. Previously, we reported that the miR-17-92 cluster plays a key role in cardiomyocyte proliferation. Here, ...we report that expression of miR-19a/19b, members of the miR-17-92 cluster, is induced in heart failure patients. We show that intra-cardiac injection of miR-19a/19b mimics enhances cardiomyocyte proliferation and stimulates cardiac regeneration in response to myocardial infarction (MI) injury. miR-19a/19b protected the adult heart in two distinctive phases: an early phase immediately after MI and long-term protection. Genome-wide transcriptome analysis demonstrates that genes related to the immune response are repressed by miR-19a/19b. Using an adeno-associated virus approach, we validate that miR-19a/19b reduces MI-induced cardiac damage and protects cardiac function. Finally, we confirm the therapeutic potential of miR-19a/19b in protecting cardiac function by systemically delivering miR-19a/19b into mice post-MI. Our study establishes miR-19a/19b as potential therapeutic targets to treat heart failure.
The efficient selective oxidation and functionalization of CH bonds with molecular oxygen and a copper catalyst to prepare the corresponding ketones was achieved with ethyl chloroacetate as a ...promoter. In this transformation, various substituted N‐heterocyclic compounds were well tolerated. Preliminary mechanistic investigations indicated that organic radical species were involved in the overall process. The N‐heterocyclic compounds and ethyl chloroacetate work synergistically to activate CH bonds in the methylene group, which results in the easy generation of free radical intermediates, thus leading to the corresponding ketones in good yields.
Molecular oxygen can be used for the selective oxidation of CH bonds of N‐heterocyclic compounds to the corresponding ketones with a copper catalyst and ethyl chloroacetate as a promoter. In this transformation, various substituted N‐heterocyclic compounds were well tolerated. Preliminary mechanistic investigations indicated that organic radical species were involved in the overall process.
Nickel is an important element on Earth, and a major element in the Earth's core, and plays important roles in many geological and biological systems. As an important sink of Ni, Ni sulfides are ...closely concerned with Ni migration in magma systems and the genesis and evolution of magmatic sulfide deposits. Ni isotopes of Ni sulfides may be a powerful geochemical tracer in magmatic processes and evolution of magmatic sulfide deposits. However Ni isotope fractionation factors of sulfides remain poorly known, which makes the applications of Ni isotopes to geological problems associated with sulfides difficult. In this study, the first-principles methods are used to compute Ni isotope fractionation parameters of polydymite (Ni3S4), heazlewoodite (Ni3S2), millerite (NiS), godlevskite (Ni9S8) and vaesite (NiS2). The reduced partition function ratios of 60Ni/58Ni (103lnβ60–58) for these minerals decrease in the order of polydymite > heazlewoodite > millerite > godlevskite > vaesite. Ni isotope fractionations in these Ni sulfides show an approximately linear dependence on the average NiS bond lengths, and have a significant negative correlation with the average NiNi bond lengths. Furthermore, a change in Fe/Ni ratio can also lead to Ni isotope fractionation, and with substitution Fe for Ni, the reduced partition function ratios of 60Ni/58Ni decrease.
Abstract
The use of gaseous and air-captured CO
2
for technical biosynthesis is highly desired, but elusive so far due to several obstacles including high energy (ATP, NADPH) demand, low ...thermodynamic driving force and limited biosynthesis rate. Here, we present an ATP and NAD(P)H-free chemoenzymatic system for amino acid and pyruvate biosynthesis by coupling methanol with CO
2
. It relies on a re-engineered glycine cleavage system with the NAD(P)H-dependent L protein replaced by biocompatible chemical reduction of protein H with dithiothreitol. The latter provides a higher thermodynamic driving force, determines the reaction direction, and avoids protein polymerization of the rate-limiting enzyme carboxylase. Engineering of H protein to effectively release the lipoamide arm from a protected state further enhanced the system performance, achieving the synthesis of glycine, serine and pyruvate at g/L level from methanol and air-captured CO
2
. This work opens up the door for biosynthesis of amino acids and derived products from air.
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