4 research outputs found
The Synergistic Effect between Metal and Sulfur Vacancy to Boost CO<sub>2</sub> Reduction Efficiency: A Study on Descriptor Transferability and Activity Prediction
Both metal center
active sites and vacancies can influence the
catalytic activity of a catalyst. A quantitative model to describe
the synergistic effect between the metal centers and vacancies is
highly desired. Herein, we proposed a machine learning model to evaluate
the synergistic index, PSyn, which is
learned from the possible pathways for CH4 production from
CO2 reduction reaction (CO2RR) on 26 metal-anchored
MoS2 with and without sulfur vacancy. The data set consists
of 1556 intermediate structures on metal-anchored MoS2,
which are used for training. The 2028 structures from the literature,
comprising both single active site and dual active sites, are used
for external test. The XGBoost model with 3 features, including electronegativity,
d-shell valence electrons of metal, and the distance between metal
and vacancy, exhibited satisfactory prediction accuracy on limiting
potential. Fe@Sv-MoS2 and Os@MoS2 are predicted
to be promising CO2RR catalysts with high stability, low
limiting potential, and high selectivity against hydrogen evolution
reactions (HER). Based on some easily accessible descriptors, transferability
can be achieved for both porous materials and 2D materials in predicting
the energy change in the CO2RR and nitrogen reduction reaction
(NRR). Such a predictive model can also be applied to predict the
synergistic effect of the CO2RR in other oxygen and tungsten
vacancy systems
Comprehensive Metabolic Profiling of Age-Related Mitochondrial Dysfunction in the High-Fat-Fed <i>ob</i>/<i>ob</i> Mouse Heart
The
ectopic deposition of fat is thought to lead to lipotoxicity
and has been associated with mitochondrial dysfunction and diabetic
cardiomyopathy. We have measured mitochondrial respiratory capacities
in the hearts of <i>ob</i>/<i>ob</i> and wild-type
mice on either a regular chow (RCD) or high-fat (HFD) diet across
four age groups to investigate the impact of diet and age on mitochondrial
function alongside a comprehensive strategy for metabolic profiling
of the tissue. Myocardial mitochondrial dysfunction was only evident
in <i>ob</i>/<i>ob</i> mice on RCD at 14 months,
but it was detectable at 3 months on the HFD. Liquid chromatography–mass
spectrometry (LC–MS) was used to study the profiles of acylcarnitines
and the accumulation of triglycerides, but neither class of lipid
was associated with mitochondrial dysfunction. However, a targeted
LC–MS/MS analysis of markers of oxidative stress demonstrated
increases in GSSG/GSH and 8-oxoguanine, in addition to the accumulation
of diacylglycerols, which are lipid species linked to lipotoxicity.
Our results demonstrate that myocardial mitochondria in <i>ob</i>/<i>ob</i> mice on RCD maintained a similar respiratory
capacity to that of wild type until a late stage in aging. However,
on a HFD, unlike wild-type mice, <i>ob</i>/<i>ob</i> mice failed to increase mitochondrial respiration, which may be
associated with a complex I defect following increased oxidative damage
Secondary metabolites isolated from <i>Penicillium christenseniae</i> SD.84 and their antimicrobial resistance effects
A pair of new quinolone alkaloid enantiomers, (Ra)-(-)-viridicatol (1) and (Sa)-(+)-viridicatol (4), and seven known compounds, namely, 2, 3 and 5–9, were isolated from Penicillium christenseniae SD.84. The structures of 1 and 4 were determined using NMR and HRESIMS data. Theoretical calculations through CD and ECD confirmed 1 and 4 as a pair of enantiomers. The MIC values of 4 against Staphylococcus aureus and methicillin-resistant S. aureus were 12.4 and 24.7 μM, respectively, compound 1 had no inhibitory activity. Antimicrobial assays of 2, 3, and 5–7 showed a moderate activity against S. aureus and methicillin-resistant S. aureus. This study demonstrated the remarkable potential of Penicillium sp. to produce new drug-resistant leading compounds, thereby advancing the mining for new sources of antimicrobial agents.</p
Additional file 1: of Mechanistic insights revealed by lipid profiling in monogenic insulin resistance syndromes
Supplementary Table S1 and Figures S1 and S2. (DOCX 102 kb