The x-,and gamma-ray emission probabilities per decay of Np-239 are determined directly from the ratio of the emission rates and the activity. The emission rates are measured with calibrated Ge(Li) ...spectrometer and activity with 4лβ-r coincidence counting device. The 277.6 keV r-ray emission probability is determined as 0.1421±0.0013. The errors of the measured results are carefully discussed and compared with the data offered by the literatures.
A photo‐involved Li‐O2 battery with carbon nitride (C3N4) is presented as a bifunctional photocatalyst to accelerate both oxygen reduction and evolution reactions. With illumination in a discharge ...process, photoelectrons generated in the conduction band (CB) of C3N4 are donated to O2 for O2−, which undergoes a second electron reduction to O22− and gives the final product of Li2O2; in a reverse process, holes left behind in the valence band (VB) of C3N4 plus an applied lower voltage than the equilibrium drive the Li2O2 oxidation. The discharge voltage is significantly increased to 3.22 V, surpassing the thermodynamic limit of 2.96 V, and the charge voltage is reduced to 3.38 V. This leads to a record‐high round‐trip efficiency of 95.3 % and energy density increase of 23.0 % compared to that in the dark.
A photo‐promoted Li‐O2 battery has carbon nitride as a bifunctional photocatalyst to accelerate the formation and decomposition of Li2O2 in the discharge and charge process. It realizes photo‐energy conversion and storage in a Li‐O2 battery with a round‐trip efficiency of 95.3 % and an output energy density increase of 23.0 % compared to that in the dark.
A photo-involved Li-O
battery with carbon nitride (C
N
) is presented as a bifunctional photocatalyst to accelerate both oxygen reduction and evolution reactions. With illumination in a discharge ...process, photoelectrons generated in the conduction band (CB) of C
N
are donated to O
for O
, which undergoes a second electron reduction to O
and gives the final product of Li
O
; in a reverse process, holes left behind in the valence band (VB) of C
N
plus an applied lower voltage than the equilibrium drive the Li
O
oxidation. The discharge voltage is significantly increased to 3.22 V, surpassing the thermodynamic limit of 2.96 V, and the charge voltage is reduced to 3.38 V. This leads to a record-high round-trip efficiency of 95.3 % and energy density increase of 23.0 % compared to that in the dark.
Based on a coordination symmetry approach, a luminescent lanthanide metal-organic framework (Ln-MOF), {Eu2(L)3(DMF)2.DMF.MeOH}n (Ln-MOF 1, H2L = 5-(4H-1,2,4-triazol-4-yl)benzene-1,3-dicarboxylic ...acid), with a 3,8-connected tfz-d net was synthesized. Ln-MOF 1 exhibits a strong red luminescence induced by the efficient antenna effect of the ligand. More importantly, Ln-MOF 1 luminescence is efficiently quenched upon exposure to polychlorinated benzenes, which are persistent organic pollutants (POPs) and cause permanent damage to human health and living environments.
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has lasted for two years and caused millions of infections and deaths in humans. Although the origin of SARS-CoV-2 infection ...in humans remains unknown, infection in animals has been frequently reported in varieties of animals all over the world. Both experimental and natural infections of SARS-CoV-2 in different animal species provide useful information on viral host range and pathogenicity. As the pandemic continues to evolve, SARS-CoV-2 infection in animals will be expanding. In this review, we summarized SARS-CoV-2 testing and infection in animals as well as SARS-CoV-2 strains and transmission in animals. Current data showed that at least 18 different animal species tested positive for SARS-CoV-2. These 18 animal species belong to pet, captive, farmed, and wild animals. Fifteen of the eighteen animal species were known to be positive for the Delta variant and ten animal species were infected with two different types of variants. Human-to-animal, animal-to-animal, and animal-to-human transmission events were suggested in different outbreaks involved in animal infection with SARS-CoV-2. Continued testing, immunization, and surveillance are warranted.
Carboxymethyl starch (CMS)/xanthan gum (XG) combinations with different ratios (CMS/XG: 1/1, 3/1, 5/1, 7/1, 9/1, w/w) were used as Pickering emulsion delivery systems to encapsulate pterostilbene ...(PTS) to improve its stability. The results showed that the Pickering emulsion prepared using CMS/XG combinations could effectively encapsulate PTS. When the mass ratio of CMS to XG was 1:1, the encapsulation efficiency reached 91.20 %. The spherical particles in the PTS emulsion were dissociated and homogenous. The results of backscattered light experiments and storage stability studies showed that the PTS emulsion system prepared using CMS/XG was uniform and stable, with no obvious phase separation or emulsion droplet coalescence. With an increase in the mass ratio of XG, the water distribution in the emulsion became more evenly distributed, and the aggregation of droplets was reduced. The PTS emulsion prepared using CMS/XG improved the storage retention percentage of PTS. The cumulative release of PTS in the simulated gastric fluid was significantly lower than that in simulated intestinal fluid. The Pickering emulsion prepared using CMS/XG combinations can be used as a delivery system for functional foods and help to develop an efficient and reliable release system for hydrophobic bioactive substances.
With the increased emergence and threat of multi-drug resistant microorganisms, MXenes have become not only an emerging class of two-dimensional functional nanomaterials, but also potential ...nanomedicines (i.e., antimicrobial agents) that deserve further exploration. Very recently, Ti3C2 MXene was observed to offer a unique membrane-disruption effect and superior light-to-heat conversion efficiency, but its antibacterial property remains unsatisfactory due to poor MXene-bacteria interactions, low photothermal therapy efficiency, and occurrence of bacterial rebound in vivo. Herein, the cationic antibiotic ciprofloxacin (Cip) is combined with Ti3C2 MXene, and a hybrid hydrogel was constructed by incorporating Cip-Ti3C2 nanocomposites into the network structure of a Cip-loaded hydrogels to effectively trap and kill bacteria. We found that the Cip-Ti3C2 nanocomposites achieved an impressive in vitro bactericidal efficiency of >99.99999% (7.03 log10) for the inhibition of methicillin-resistant Staphylococcus aureus (MRSA) by combining chemotherapy with photothermal therapy. In an MRSA-induced murine abscess model, the hybrid hydrogel simultaneously achieved high-efficiency sterilization and long-term inhibition effects, avoiding the rebound of bacteria after photothermal therapy, and thus maximized the in vivo therapeutic efficacy of Ti3C2 MXene-based systems. Overall, this work provides a strategy for efficiently combating localized bacterial infection by rationally designing MXene-based hybrid hydrogels.
Two-dimensional Ti3C2 MXene was recently regarded as a promising functional nanomaterial, however, its antibacterial applications are limited by the poor MXene-bacteria interactions, low photothermal therapy efficiency, and the occurrence of bacterial rebound in vivo. This work aims to construct a Ti3C2 MXene-based hybrid hydrogel for chemo-photothermal therapy and enhance the antimicrobial performance via a combination of the high-efficiency sterilization of ciprofloxacin-Ti3C2 nanocomposites with the long-term inhibition effect of ciprofloxacin hydrogel. The present study provides an example of efficient MXene-based antimicrobials to treat localized bacterial infection such as methicillin-resistant Staphylococcus aureus (MRSA)-induced skin abscess.
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The development of novel antimicrobials is a top priority to address the growing epidemic of multidrug-resistant pathogens. Since cationic nonamphiphilic star-shaped antimicrobials are promising ...molecular scaffolds that provide a high charge density in binding anionic bacterial bilayers, this research aimed to further increase their membrane perturbation capability by introducing guanidinium groups to the antimicrobials via enhancing membrane insertion. In particular, computational simulation and experimental investigations revealed that our designed guanidinium-rich alternating copolypeptide, four-armed poly(arginine-alt-glycine), can interact with both the headgroups and unsaturated tails of phospholipids in bacterial membranes through multiple interactions, including electrostatic, cation−π, and T-shaped π–π interactions, allowing it to penetrate deeper inside the biologically inaccessible high-energy barrier of the hydrophobic lipid bilayer interior to cause membrane permeabilization and precipitation of the bacterial cytoplasm. Furthermore, glycine was observed to have a unique effect in enhancing the performance of arginine-based copolypeptide. Four-armed poly(arginine-alt-glycine) exhibited broad-spectrum antimicrobial activity, high bactericidal efficiency, and negligible hemolysis. The in vivo antibacterial performance of the copolypeptide was superior to that of doxycycline in a mouse model of Pseudomonas aeruginosa skin infection, accompanied by negligible local and systemic toxicity. Our results demonstrate that this guanidinium-rich, nonamphiphilic, star-shaped structure may promote the development of next-generation antimicrobials.
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