The geochemical behavior of nickel, an essential trace metal element, strongly depends on its interactions with Mn oxides. Interactions between the phyllomanganate birnessite and sorbed or ...structurally incorporated Ni have been extensively documented together with the fate of Ni along the transformation of these layered species to tunnel Mn oxides (tectomanganates). By contrast, interactions of phyllomanganates with weakly bound Ni species hydrated Ni, Ni (hydr)oxides, that possibly prevail in natural Ni-rich (>10% NiO) manganates, have received little attention and the influence of these Ni species on the phyllomanganate-to-tectomanganate transformation remains essentially unknown. A set of phyllomanganate precursors with contrasting contents of Ni was thus prepared and subjected to a reflux treatment mimicking the natural phyllomanganate-to-tectomanganate conversion. Layered precursors and reflux products were characterized with a combination of diffractometric, spectroscopic, thermal, and chemical methods. Ni is essentially present as hydrated Ni(II) and Ni(II) (hydr)oxides in Ni-rich layered precursors whereas Ni(II) sorbed at particle edges prevail at low Ni content. No Ni sorbed at layer vacancy sites or structurally incorporated was detected in the initial vacancy-free layered precursors. Consistent with the high content (≈1/3) of Jahn-Teller distorted Mn(III) octahedra in layered precursors, which is favorable to their conversion to tectomanganates, Ni-free samples fully convert to an a-disordered todorokite, a common tectomanganate with a 3 × 3 tunnel structure. Contrastingly and despite similar high Mn(III) contents in Ni-rich precursors, hydrolysis of interlayer Ni2+ and polymerization of Ni(OH)2 in phyllomanganate interlayers is kinetically favored during reflux process. Asbolane, a phyllomanganate with an incomplete – island-like – octahedral layer of metal (hydr)oxides, is thus formed rather than todorokite. A nitric acid treatment, aiming at the dissolution of the island-like interlayer Ni(OH)2 layer, allows an easy and unambiguous differentiation between asbolane and todorokite, the latter being unaffected by the treatment. Both compounds exhibit indeed similar interplanar periodicities and can be confused when using X-ray diffraction, despite contrasting intensity ratios. Migration rate of Mn(III) out of the MnO2 layer relative to the metal hydrolysis and polymerization rate determines the formation of todorokite or asbolane. Here, Ni(OH)2 polymerization hampers the formation of tectomanganates and likely contributes to the prevalence of phyllomanganates over tectomanganates in natural Ni-rich environments. Most Ni is retained during the reflux process, part of Ni (≈20%) being likely structurally incorporated in the reaction products, thus enhancing the sequestration of Ni in Mn oxides.
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•A high-performance Pd SAs catalyst (PdSAs/NC) was developed from Pd@UiO-66-NH2.•Synergistic effect between Pd SAs and NPs enhanced hydrogenation activity.•Catalyst exhibited 100% ...conversion of HMF and 98% selectivity towards BHMTHF at 0 °C.•Synergistic mechanism of Pd SAs and NPs was revealed by experiment and DFT results.
Selective reduction of 5-hydroxymethylfurfural (HMF) to valuable 2,5-bis(hydroxymethyl)tetrahydrofuran (BHMTHF) remains a significant challenge under mild conditions. The synergistic effect between metal single atoms (SAs) and nanoparticles (NPs) can greatly enhance catalytic activity. Here, a high-performance Pd SAs catalyst supported on N-doped carbon (PdSAs/NC) was developed from Pd@UiO-66-NH2. It was found that partial Pd SAs were spontaneously restructured into Pd NPs during the reaction. Our catalyst exhibited 100% conversion of HMF and 98% selectivity towards BHMTHF at temperature as low as 0 °C. In situ FTIR spectra results and density functional theory calculations indicate that Pd SAs contribute to the C = O activation, while Pd NPs facilitated the H2 dissociation into H* atoms, resulting in synergistic catalytic activity between Pd SAs and Pd NPs.
To quantitatively assess and compare the effectiveness and safety of posterior fossa decompression with duraplasty (PFDD) and posterior fossa decompression (PFD) in treating patients with Chiari ...malformation type I.
PubMed, Embase, and Cochrane Library were searched through May 2017. Fourteen cohort studies comprising 3666 patients with Chiari malformation type I were included. Studies were pooled, and the relative risk (RR) and corresponding 95% confidence interval (CI) were calculated.
The decrease in syringomyelia was better in patients in the PFDD group than in patients in the PFD group (RR = 1.57, 95% CI = 1.07–2.32, Pheterogeneity = 0.042, I2 = 56.6%). The incidence of cerebrospinal fluid leak (RR = 5.23, 95% CI = 2.61–10.51, Pheterogeneity = 0.830, I2 = 0%) and aseptic meningitis (RR = 4.02, 95% CI = 1.46–11.03, Pheterogeneity = 0.960, I2 = 0%) significantly increased among patients in the PFDD group compared with patients in the PFD group. When stratifying by age, a significantly reduced risk in the reoperation rate was observed in the adult group. However, the clinical improvement and the incidence of wound infection were not significantly different between the 2 groups.
This study confirmed that the decrease in syringomyelia was better for patients treated with PFDD than for patients treated with PFD alone. However, no significant difference was found in the clinical improvement and the reoperation rate between the 2 groups.
•The decrease in syringomyelia was better for patients in the PFDD group than for patients in the PFD group.•No significant difference was found in clinical improvement and reoperation rate between the 2 groups.•Further studies with a larger data set are required to validate these findings.
Ferroptosis is an iron-regulated, caspase-mediated pathway of cell death that is associated with the excessive aggregation of lipid-reactive oxygen species and is extensively involved in the ...evolution of many diseases, including epilepsy. The superoxide anion (O2 •–), as the primary precursor of ROS, is closely related to ferroptosis-mediated epilepsy. Therefore, it is crucial to establish a highly effective and convenient method for the real-time dynamic monitoring of O2 •– during the ferroptosis process in epilepsy for the diagnosis and therapy of ferroptosis-mediated epilepsy. Nevertheless, no probes for detecting O2 •– in ferroptosis-mediated epilepsy have been reported. Herein, we systematically conceptualized and developed a novel near-infrared (NIR) fluorescence probe, NIR-FP, for accurately tracking the fluctuation of O2 •– in ferroptosis-mediated epilepsy. The probe showed exceptional sensitivity and outstanding selectivity toward O2 •–. In addition, the probe has been utilized effectively to bioimage and evaluate endogenous O2 •– variations in three types of ferroptosis-mediated epilepsy models (the kainic acid-induced chronic epilepsy model, the pentylenetetrazole-induced acute epilepsy model, and the pilocarpine-induced status epilepticus model). The above applications illustrated that NIR-FP could serve as a reliable and suitable tool for guiding the accurate diagnosis and therapy of ferroptosis-mediated epilepsy.
Silicosis is a well‐acknowledged occupational lung disease caused by inhalation of a large amount of free silica dust during the production period and eventually a considerable negative impact on the ...patients' quality of life. Autophagy exerts a critical influence on immune and inflammatory responses during the pathogenesis of pulmonary fibrosis. In this study, we sought to determine whether autophagy is involved in silicosis's pathogenesis and how it may affect pulmonary cellular physiology. In the animal experiments, we found persistent activation of autophagy in the development of pulmonary fibrosis, which was also accompanied by tumor necrosis factor and transforming growth factor expression increased. Therefore, the autophagy signaling pathway may regulate the inflammatory response and affect the progression of fibrosis. Further, in vitro experiments, we used LY294002, RAPA, and N‐acetylcysteine (NAC) intervened autophagy. Our results showed that PI3K/Akt/mTOR signaling pathway is involved in the autophagy changed mediated by SiO2 exposed, and autophagy might play a protective role in the progression of pulmonary fibrosis. Additionally, NAC's effect is not apparent on SiO2‐mediated autophagy through the PI3K/Akt/mTOR signaling pathway, but it can reduce the inflammatory response on NR8383 cells mediated by SiO2‐exposed. Nevertheless, it's interesting that NAC can reduce the inflammatory response on NR8383 cells mediated by SiO2‐exposed. Taken together, our data demonstrated that SiO2‐exposed can induce pulmonary fibrosis along with autophagy both in vivo and in vitro, NAC could alleviate the inflammatory response NR8383 cells by SiO2‐exposed through non PI3K/Akt/mTOR signaling pathway, and the specific mechanism of its action needs further studying.
Schwertmannite effectively sorbs chromate (Cr(VI)), yet the sorption mechanisms remain elusive. We determined the Cr(VI) sorption mechanisms on schwertmannite at pH 3.2 and 5 using combined ...macroscopic sorption experiments with molecular-scale characterization and by comparing them to arsenate (As(V)) sorption. Cr(VI) adsorbs as bidentate-binuclear (BB) inner-sphere complexes through exchanging more sulfate and less >Fe–OH/OH2, with 0.59–0.71 sulfate released per Cr(VI) sorbed. While As(V) also forms BB complexes, it exchanges sulfate and >Fe–OH/OH2 equally with 0.49–0.52 sulfate released per As(V) sorbed. At high As(V) loadings, As(V) precipitates as amorphous FeAsO4, particularly at low pH. The abovementioned differences between Cr(VI) and As(V) can be related to their different ionic radii and binding strength. Moreover, Cr(VI) and As(V) preferentially exchange sulfate inner-sphere complexes, increasing the proportion of sulfate outer-sphere complexes in schwertmannite. In turn, the concentration of sulfate outer-sphere complexes increases and then decreases with increasing Cr(VI) loading. Results suggest that an oxyanion, which would form inner-sphere complexes on a mineral surface, preferentially exchanges inner-spherically bound oxyanions than outer-spherically bound ones on the surface, even though both are exchanged. This study improves our understanding of the sorption of oxyanions on schwertmannite and their capabilities to template schwertmannite formation and stabilize its structure.
Objective
To provide clinical management guidelines for novel coronavirus (COVID‐19) in pregnancy.
Methods
On February 5, 2020, a multidisciplinary teleconference comprising Chinese physicians and ...researchers was held and medical management strategies of COVID‐19 infection in pregnancy were discussed.
Results
Ten key recommendations were provided for the management of COVID‐19 infections in pregnancy.
Conclusion
Currently, there is no clear evidence regarding optimal delivery timing, the safety of vaginal delivery, or whether cesarean delivery prevents vertical transmission at the time of delivery; therefore, route of delivery and delivery timing should be individualized based on obstetrical indications and maternal–fetal status.
Currently, there is no clear evidence regarding optimal delivery timing or route of delivery for pregnant women with COVID‐19 infection; these should be individualized based on obstetrical indications and maternal–fetal status.
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•S-scheme heterojunction can account for the charge transfer pathway in m-FBVO/APO.•The charge transfer is improved by Co-doping of Fe2+/Fe3+ pairs re-dox cycling.•The system exhibits ...stable environmental adaptability at pH 3–7.•The degradation system of various antibiotics by visible-light-driven photo-Fenton is achieved.
A Fe2+/Fe3+ co-doped BiVO4/Ag3PO4 S-scheme heterojunction catalyst was synthesized by a simple hydrothermal method and applied to achieve efficient photo-Fenton for antibiotics degradation (99.70 %). The co-doping of Fe3+/Fe2+ highlighted red shift of optical absorption edge (535–800 nm) and adjustable band structure of BiVO4/Ag3PO4. The collaborative system of photocatalytic and Fenton could maintain high catalytic activity and stability in the treat of simulated actual water and high efficiency within wide pH conditions (3–7). The degradation experiments were employed to show removal efficiency on tetracyclines and quinolones antibiotics including tetracycline (TC), ciprofloxacin (CIP), doxycycline (DO), levofloxacin (LEV), norfloxacin (NOR), and enrofloxacin (ENR). Mechanism exploration elaborated that the m-FBVO/APO composites with dominant Fe2+ preserved both high oxidation potential (<−0.33 eV vs NHE) and reduction potential (>2.45 eV vs NHE) through the constructed BiVO4/Ag3PO4 S-scheme heterojunction. Efficient e−/h+ pairs separation was further achieved through Fe3+/Fe2+ pairs cycling. And degradation pathway of TC was mainly investigated to verify its mineralization. This work provides a new sight towards catalytic mechanisms in heterogeneous photo-Fenton degradation systems.
Calmodulin (CaM) regulates plant disease responses through its downstream calmodulin-binding proteins (CaMBPs) often by affecting the biosynthesis or signaling of phytohormones, such as jasmonic acid ...(JA) and salicylic acid. However, how these CaMBPs mediate plant hormones and other stress resistance-related signaling remains largely unknown. In this study, we conducted analyses in Arabidopsis (
) on the functions of AtIQM1 (IQ-Motif Containing Protein1), a Ca
-independent CaMBP, in JA biosynthesis and defense against the necrotrophic pathogen
using molecular, biochemical, and genetic analyses. IQM1 directly interacted with and promoted
(
) expression and CAT2 enzyme activity and indirectly increased the activity of the JA biosynthetic enzymes ACX2 and ACX3 through CAT2, thereby positively regulating JA content and
resistance. In addition, in vitro assays showed that in the presence of CaM5, IQM1 further enhanced the activity of CAT2, suggesting that CaM5 may affect the activity of CAT2 by combining with IQM1 in the absence of Ca
Our data indicate that IQM1 is a key regulatory factor in signaling of plant disease responses mediated by JA. The study also provides new insights that CaMBP may play a critical role in the cross talk of multiple signaling pathways in the context of plant defense processes.
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