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Comparison of the performances between ChatGPT and Gemini in answering questions on viral hepatitis
Efficient amine-assisted CO2 hydrogenation to methanol co-catalyzed by metallic and oxidized sites within ruthenium clusters
Projected increase in droughts over the Arabian Peninsula and associated uncertainties
Molecular basis for the enzymatic inactivity of class III glutaredoxin ROXY9 on standard glutathionylated substrates
Abstract Class I glutaredoxins (GRXs) are nearly ubiquitous proteins that catalyse the glutathione (GSH)-dependent reduction of mainly glutathionylated substrates. In land plants, a third class of GRXs has evolved (class III). Class III GRXs regulate the activity of TGA transcription factors through yet unexplored mechanisms. Here we show that Arabidopsis thaliana class III GRX ROXY9 is inactive as an oxidoreductase on widely used model substrates. Glutathionylation of the active site cysteine, a prerequisite for enzymatic activity, occurs only under highly oxidizing conditions established by the GSH/glutathione disulfide (GSSG) redox couple, while class I GRXs are readily glutathionylated even at very negative GSH/GSSG redox potentials. Thus, structural alterations in the GSH binding site leading to an altered GSH binding mode likely explain the enzymatic inactivity of ROXY9. This might have evolved to avoid overlapping functions with class I GRXs and raises questions of whether ROXY9 regulates TGA substrates through redox regulation.
Synthesis and structural insights of bis(2-methoxy-6-{[(2-methylpropyl)imino]methyl}phenolato) nickel (II) complex through DFT and docking investigations
AbstractNickel complexes are a potential candidate for antibacterial and antifungal activity. A new Ni (II) complex, bis(2-methoxy-6-{[(2-methylpropyl)imino]methyl}phenolato)nickel (II) (2), was synthesised by reacting, bis(3-methoxy-salicylaldehyde)nickel (II) (1) with isobutylamine. It was characterised by single crystal X-ray diffraction (ScXRD), UV-Vis, NMR, IR, mass spectrometry, and thermogravimetry (TG) to study its structure and physico-chemical properties. The ScXRD showed a square planar geometry, and monoclinic crystal system with a space group P21/n. The TG analysis revealed its thermal durability pre and post-melting up to 225 oC with a weight loss of only 2%. The optimized molecular structure, energy gap between HOMO and LUMO, and intermolecular interactions were studied by computational methods. The microbial activity evaluation showed significant anti-bacterial activity against E. coli and S. aureus when the concentration exceeded 40 µg/mL, and a prominent anti-fungal activity over C. albicans and C. tropicalis above 30 µg/mL. The values of minimum inhibitory concentration (MIC) for bacteria (MIB) and fungi (MIF) implied its potential to inhibit the growth of microbes. Docking studies revealed that the molecule binds well with proteins such as PDB: 2W9H for Dihydrofolate Reductase of S.aureus as shown by its binding energy of -8.62 kcal.mol− 1.
Sequential addition of cations increases photoluminescence quantum yield of metal nanoclusters near unity
AbstractPhotoluminescence is one of the most intriguing properties of metal nanoclusters derived from their molecular-like electronic structure, however, achieving high photoluminescence quantum yield (PLQY) of metal core-dictated fluorescence remains a formidable challenge. Here, we report efficient suppression of the total structural vibrations and rotations, and management of the pathways and rates of the electron transfer dynamics to boost a near-unity absolute PLQY, by decorating progressive addition of cations. Specifically, with the sequential addition of Zn2+, Ag+, and Tb3+ into the 3-mercaptopropionic acids capped Au nanoclusters (NCs), the low-frequency vibration of the metal core progressively decreases from 144.0, 55.2 to 40.0 cm−1, and the coupling strength of electrons-high-frequency vibration related to surface motifs gradually diminishes from 40.2, 30.5 to 14.4 meV. Moreover, introducing cation additives significantly reduces electron transfer time from 40, 27 to 12 ps in the pathway from staple motifs to the metal core. This benefits from the shrinkage of the total structure that speeds up the shell-core electron transition, and in particular, the Tb3+ provides a hopping platform for the excited electrons as their intrinsic ladder-like energy level structure. As a result, it allows a remarkable enhancement in PLQY, from 51.2%, 83.4%, up to 99.5%.
Time-varying 3D optical torque via a single beam
The role of direct air capture in achieving climate-neutral aviation
Abstract Growing demand for air travel and limited scalable solutions pose significant challenges to the mitigation of aviation’s climate change impact. Direct air capture (DAC) may gain prominence due to its versatile applications for either carbon removal (direct air carbon capture and storage, DACCS) or synthetic fuel production (direct air carbon capture and utilization, DACCU). Through a comprehensive and time-dynamic techno-economic assessment, we explore the conditions for synthetic fuels from DACCU to become cost-competitive with an emit-and-remove strategy based on DACCS under 2050 CO 2 and climate neutrality targets. We find that synthetic fuels could achieve climate neutrality at lower cost than an emit-and-remove strategy due to their ability to cost-effectively mitigate contrails. Under demand reductions, contrail avoidance, and CO 2 neutrality targets the cost advantage of synthetic fuels weakens or disappears. Low electricity cost (€0.02 kWh -1 ) and high fossil kerosene prices (€0.9 l -1 ) can favor synthetic fuels’ cost-competitiveness even under these conditions. Strategic interventions, such as optimal siting and the elimination of fossil fuel subsidies, can thus favor a shift away from fossil-reliant aviation.
Engineered hypoxia-responsive albumin nanoparticles mediating mitophagy regulation for cancer therapy
Cryo-EM structure of an activated GPR4–Gs signaling complex
CF2H-synthon enables asymmetric radical difluoroalkylation for synthesis of chiral difluoromethylated amines
Tailoring pyridine bridged chalcogen-concave molecules for defects passivation enables efficient and stable perovskite solar cells
Influence of aluminium distribution on the diffusion mechanisms and pairing of [Cu(NH3)2]+ complexes in Cu-CHA
AbstractThe performance of Cu-exchanged chabazite (Cu-CHA) for the ammonia-assisted selective catalytic reduction of NOx (NH3-SCR) depends critically on the presence of paired $${[{{{\rm{Cu}}}}{({{{{\rm{NH}}}}}_{3})}_{2}]}^{+}$$ [ Cu ( NH 3 ) 2 ] + complexes. Here, a machine-learning force field augmented with long-range Coulomb interactions is developed to investigate the effect of Al-distribution and Cu-loading on the mobility and pairing of $${[{{{\rm{Cu}}}}{({{{{\rm{NH}}}}}_{3})}_{2}]}^{+}$$ [ Cu ( NH 3 ) 2 ] + complexes. Performing unbiased and constrained molecular dynamics simulations, we obtain unique information inaccessible to first-principle calculations and experiments. The free energy barrier for $${[{{{\rm{Cu}}}}{({{{{\rm{NH}}}}}_{3})}_{2}]}^{+}$$ [ Cu ( NH 3 ) 2 ] + diffusion between CHA-cages depends sensitively on both the local and distant Al-distribution. Importantly, certain Al-distributions and arrangements of neighboring $${[{{{\rm{Cu}}}}{({{{{\rm{NH}}}}}_{3})}_{2}]}^{+}$$ [ Cu ( NH 3 ) 2 ] + and $${{{{{\rm{NH}}}}}_{4}}^{+}$$ NH 4 + cations make paired $${[{{{\rm{Cu}}}}{({{{{\rm{NH}}}}}_{3})}_{2}]}^{+}$$ [ Cu ( NH 3 ) 2 ] + complexes exothermic with respect to separated configurations. Our results suggest that the NH3-SCR activity can be enhanced by increasing the Cu-loading and Al-content. The dynamic interplay between $${[{{{\rm{Cu}}}}{({{{{\rm{NH}}}}}_{3})}_{2}]}^{+}$$ [ Cu ( NH 3 ) 2 ] + and $${{{{{\rm{NH}}}}}_{4}}^{+}$$ NH 4 + diffusion is crucial for the $${[{{{\rm{Cu}}}}{({{{{\rm{NH}}}}}_{3})}_{2}]}^{+}$$ [ Cu ( NH 3 ) 2 ] + mobility and stresses the need to explore large systems including long-range Coulomb interactions when studying diffusion of charged species in zeolites.
A membrane-targeted photoswitch restores physiological ON/OFF responses to light in the degenerate retina
The art and science of translucent color organic solar cells
Northern Scandinavian mountains supported by a low-grade eclogitic crustal keel
Inhibited peroxidase activity of peroxiredoxin 1 by palmitic acid exacerbates nonalcoholic steatohepatitis in male mice
Evolution of Omicron lineage towards increased fitness in the upper respiratory tract in the absence of severe lung pathology
Abstract The emergence of the Omicron lineage represented a major genetic drift in SARS-CoV-2 evolution. This was associated with phenotypic changes including evasion of pre-existing immunity and decreased disease severity. Continuous evolution within the Omicron lineage raised concerns of potential increased transmissibility and/or disease severity. To address this, we evaluate the fitness and pathogenesis of contemporary Omicron variants XBB.1.5, XBB.1.16, EG.5.1, and JN.1 in the upper (URT) and lower respiratory tract (LRT). We compare in vivo infection in Syrian hamsters with infection in primary human nasal and lung epithelium cells and assess differences in transmissibility, antigenicity, and innate immune activation. Omicron variants replicate efficiently in the URT but display limited pathology in the lungs compared to previous variants and fail to replicate in human lung organoids. JN.1 is attenuated in both URT and LRT compared to other Omicron variants and fails to transmit in the male hamster model. Our data demonstrate that Omicron lineage evolution has favored increased fitness in the URT.