Molybdenum sulfides are very attractive noble-metal-free electrocatalysts for the hydrogen evolution reaction (HER) from water. The atomic structure and identity of the catalytically active sites ...have been well established for crystalline molybdenum disulfide (c-MoS2) but not for amorphous molybdenum sulfide (a-MoSx), which exhibits significantly higher HER activity compared to its crystalline counterpart. Here we show that HER-active a-MoSx, prepared either as nanoparticles or as films, is a molecular-based coordination polymer consisting of discrete Mo3S13(2-) building blocks. Of the three terminal disulfide (S2(2-)) ligands within these clusters, two are shared to form the polymer chain. The third one remains free and generates molybdenum hydride moieties as the active site under H2 evolution conditions. Such a molecular structure therefore provides a basis for revisiting the mechanism of a-MoSx catalytic activity, as well as explaining some of its special properties such as reductive activation and corrosion. Our findings open up new avenues for the rational optimization of this HER electrocatalyst as an alternative to platinum.
The NiCo
2
O
4
ternary transition metal oxide (NCO) has been received a great interest as anode material for sodium-ion batteries, recently. Here we show that a composite material composed of NCO ...nanoparticles (NCO-NPs) and amorphous carbon (NCO/C composite) displayed a superior electrochemical performance over the NCO-NPs. The NCO-NPs delivered a capacity of 172 mAh g
−1
at the current density of 50 mA g
−1
, and the capacity was reduced to 29 mAh g
−1
after 50 cycles. The NCO/C composite showed a capacity of 213 mAh g
−1
at 50 mA g
−1
; the capacity was lowered to 119 mAh g
−1
after 100 cycles. The capacity of the composite at 100 mA g
−1
, 200 mA g
−1
and 300 mA g
−1
was ca. 123 mAh g
−1
, 93 mAh g
−1
and 62 mAh g
−1
, respectively. This improvement is ascribed to the presence of the activated hard carbon of high electronic conductivity. Our work suggests that the combination of amorphous carbon with the NCO-NPs can serve as anodes for sodium-ion batteries.
Background and AimsThe MUC13 transmembrane mucin is highly and constitutively expressed in the small and large intestine. Although MUC13 polymorphisms have been associated with human inflammatory ...bowel diseases and susceptibility to Escherichia coli infection in pigs, the biological functions of MUC13 are unknown. This study aimed to explore whether MUC13 modulates intestinal inflammation.MethodsMuc13−/− mice were generated, phenotyped and challenged with the colitis-inducing agent, dextran sodium sulphate (DSS). Colitis was assessed by clinical symptoms and intestinal histopathology. Intestinal epithelial cell apoptosis and proliferation, macrophage infiltration and cytokine production were also quantified. Apoptosis of human LS513 intestinal epithelial cells in response to apoptotic agents, including DSS, was also measured, following knockdown of MUC13 with siRNA.ResultsMuc13−/− mice were viable, fertile and developed normally, with no spontaneous intestinal pathology except mild focal neutrophilic inflammation in the small and large intestines of old mice. In response to DSS challenge, Muc13−/− mice developed more severe acute colitis, as reflected by increased weight loss, rectal bleeding, diarrhoea and histological colitis scores compared with wild-type mice. Increased numbers of F4/80+ macrophages in inflamed mucosa of Muc13−/− mice were accompanied by increased expression of intestinal IL-1β and TNFα mRNA. Muc13−/− mice had significantly increased intestinal epithelial cell apoptosis within 3 days of DSS exposure. LS513 cells were more susceptible to DSS, actinomycin-D, ultraviolet irradiation and TRAIL-induced apoptosis when MUC13 was knocked down by siRNA.ConclusionsThese novel findings indicate a protective role for Muc13 in the colonic epithelium by inhibiting toxin-induced apoptosis and have important implications for intestinal infections, inflammatory diseases and the development of intestinal cancer.
BACKGROUND
Emerging transfusion‐transmissible pathogens, including arboviruses such as West Nile, Zika, dengue, and Ross River viruses, are potential threats to transfusion safety. The most prevalent ...arbovirus in humans in Australia is Ross River virus (RRV); however, prevalence varies substantially around the country. Modeling estimated a yearly risk of 8 to 11 potentially RRV‐viremic fresh blood components nationwide. This study aimed to measure the occurrence of RRV viremia among donors who donated at Australian collection centers located in areas with significant RRV transmission during one peak season.
STUDY DESIGN AND METHODS
Plasma samples were collected from donors (n = 7500) who donated at the selected collection centers during one peak season. Viral RNA was extracted from individual samples, and quantitative reverse transcription‐polymerase chain reaction was performed.
RESULTS
Regions with the highest rates of RRV transmission were not areas where donor centers were located. We did not detect RRV RNA among 7500 donations collected at the selected centers, resulting in a zero risk estimate with a one‐sided 95% confidence interval of 0 to 1 in 2019 donations.
CONCLUSION
Our results suggest that the yearly risk of collecting a RRV‐infected blood donation in Australia is low and is at the lower range of previous risk modeling. The majority of Australian donor centers were not in areas known to be at the highest risk for RRV transmission, which was not taken into account in previous models based on notification data. Therefore, we believe that the risk of RRV transfusion transmission in Australia is acceptably low and appropriately managed through existing risk management, including donation restrictions and recall policies.
Combination of co-precipitation and hydrothermal methods is a promising route to synthesize various materials. Herein, we synthesized reduced graphene oxide/manganese ferrite (rGO/MnFe
2
O
4
) ...nanocomposites through combining a co-precipitation reaction of Mn
2+
and Fe
3+
ions in GO solution with subsequent hydrothermal treatment at different temperatures (80, 130, and 180 °C). The resulting rGO/MnFe
2
O
4
nanocomposites were characterized using X-ray diffractometry, Fourier-transform infrared spectroscopy, scanning and transmission electron microscopy, and magnetic measurements at room temperature. The influence of hydrothermal temperature on structural, morphological, magnetic and As(III) adsorption properties of rGO/MnFe
2
O
4
nanocomposites was studied. Increasing hydrothermal temperature leads to better crystallinity, magnetic properties, and As(III) adsorption capacity. At the hydrothermal temperature of 180 °C, the resulting rGO/MnFe
2
O
4
nanocomposites exhibited a crystalline size of 37.2 nm, saturated magnetization of 22.7 emu/g, and As(III) removal efficiency of 83% at neutral pH (pH ≈ 7).
In this paper, we studied the electronic properties, effective masses, and carrier mobility of monolayer
MoS
2
using density functional theory calculations. The carrier mobility was considered by ...means of
ab initio
calculations using the Boltzmann transport equation coupled with deformation potential theory. The effects of mechanical biaxial strain on the electronic properties, effective mass, and carrier mobility of monolayer
MoS
2
were also investigated. It is demonstrated that the electronic properties, such as band structure and density of state, of monolayer
MoS
2
are very sensitive to biaxial strain, leading to a direct–indirect transition in semiconductor monolayer
MoS
2
. Moreover, we found that the carrier mobility and effective mass can be enhanced significantly by biaxial strain and by lowering temperature. The electron mobility increases over 12 times with a biaxial strain of 10%, while the carrier mobility gradually decreases with increasing temperature. These results are very useful for the future nanotechnology, and they make monolayer
MoS
2
a promising candidate for application in nanoelectronic and optoelectronic devices.
This work presents an approach for using direct writing of graphene–cobalt ferrite (GP-CoFe) as a hybrid electrode material in supercapacitors. First, the hybrid ink was prepared from an aqueous ...colloid of sodium dodecyl sulfate-functionalized graphene and cobalt ferrite nanoparticles. Second, the ink was printed on graphite paper substrates by using direct ink writing; then, the electrodes were treated in a microwave for different durations. As-printed electrodes were characterized by scanning electron microscopy; transmission electron microscopy, and serval electrochemical techniques, such as open-circuit voltage measurement, cyclic voltammetry, and electrochemical impedance spectroscopy. Finally, the GP-CoFe electrodes after microwave treatment for 60 min exhibited the highest specific capacitance of 304 F/g at a charge/discharge current density of 0.83 A/g, and good electrochemical durability with 94.68% capacitance retention after 16,000 cycles. This work thus provides an efficient method to fabricate a high-performance supercapacitor electrode.
Graphic Abstract
The efficient removal of organic refractory pollutants such as dyes and antibiotics in wastewater is crucial for protecting the environment and human health. In this work, a NiCo-layered double ...hydroxide (NiCo-LDH) with a uniform microspherical, hierarchical structure and a high surface area was successfully synthesized as an effective peroxymonosulfate (PMS) activator for the degradation of various organic dyes and antibiotics. The influence of various parameters on the catalytic activity of the NiCo-LDH was determined. Radical scavenger studies unveiled the major reactive oxygen species (ROSs) generated in the NiCo-LDH/PSM system to be 1O2, SO4•−, and O2•−. Ex-situ X-ray photoelectron spectroscopy (XPS) analysis uncovered the role of Co sites and oxygen vacancy as active sites and revealed the reversible redox properties of NiCo-LDH based on Co2+/Co3+ cycles. The activation mechanism and Rhodamine B (RhB) degradation pathways were experimentally studied and proposed. The NiCo-LDH is highly versatile, reusable and stable as shown by post-catalysis characterizations. This work shows the excellent catalysis performances and provides insights into the activation mechanism of PMS by NiCo-LDH for organic pollutant remediation.
•Solvothermal synthesis of NiCo-LDH microspheres with high surface area.•NiCo-LDH/PMS system shows excellent efficiency towards RhB degradation.•Reactive oxygen species are 1O2, SO4− and O2−.•Co2+/Co3+ cycles and oxygen vacancies are responsible for PMS activation.•NiCo-LDH/PMS system is promising for real wastewater treatment.
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