55 research outputs found
Unveiling new stable manganese based photoanode materials via theoretical high-throughput screening and experiments
With the increasing energy demand, developing renewable fuel production strategies such as photoelectrocatalytic hydrogen production is critical to mitigating the global climate change. In this work, we experimentally validate a new stable and photoactive material, MgâMnOâ, from the exhaustive theoretical exploration of the chemical space of X (=Mg and Ca), Mn and O
Anti-inflammatory effects of isoketocharbroic acid from brown alga, Sargassum micracanthum
During our on-going screening program designed to isolate natural compounds from marine environments, we isolated isoketochabrolic acid (IKCA) from Sargassum micracanthum, an important brown algae distributed in Jeju Island, Korea. Furthermore, we evaluated the inhibitory effects of IKCA on nitric oxide (NO) production in lipopolysaccharide (LPS)-triggered macrophages. IKCA strongly inhibited NO production, with an IC50 value of 58.31 ÎŒM. Subsequent studies demonstrated that IKCA potently and concentration-dependently reduced prostaglandin E2 (PGE2), tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1ÎČ, and IL-6 cytokine production. In conclusion, to the best of our knowledge, this is the first study to show that IKCA isolated from S. micracanthum has a potent anti-inflammatory activity. Therefore, IKCA might be useful as an anti-inflammatory health supplement or functional cosmetics
MTHFR C677T Polymorphism as a Risk Factor for Vascular Calcification in Chronic Hemodialysis Patients
Polymorphism of 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T is one of the suggested risk factors for atherosclerosis. However, few studies have reported on the relationship between MTHFR C677T polymorphism and vascular calcification (VC) in chronic hemodialysis patients. We investigated the relationship between the MTHFR C677T polymorphism and VC in 152 chronic hemodialysis patients. Patients with a TT genotype exhibited significantly higher VC scores than patients expressing CC and CT (P = 0.002). The prevalence of peripheral vascular disease increased with the incidence of MTHFR C677T mutations for all patients, and the incidence of cerebrovascular accidents also increased with the presence of mutations for young patients (†60 yr) (P < 0.05). Patients with CT and TT genotypes had adjusted odds ratios for VC of 1.39 and 1.58, respectively (P < 0.05). In summary, these data suggest that the MTHFR C677T polymorphism affects the degree of VC in chronic hemodialysis patients
Accelerated chemical science with AI
In light of the pressing need for practical materials and molecular solutions to renewable energy and health problems, to name just two examples, one wonders how to accelerate research and development in the chemical sciences, so as to address the time it takes to bring materials from initial discovery to commercialization. Artificial intelligence (AI)-based techniques, in particular, are having a transformative and accelerating impact on many if not most, technological domains. To shed light on these questions, the authors and participants gathered in person for the ASLLA Symposium on the theme of âAccelerated Chemical Science with AIâ at Gangneung, Republic of Korea. We present the findings, ideas, comments, and often contentious opinions expressed during four panel discussions related to the respective general topics: âDataâ, âNew applicationsâ, âMachine learning algorithmsâ, and âEducationâ. All discussions were recorded, transcribed into text using Open AI's Whisper, and summarized using LG AI Research's EXAONE LLM, followed by revision by all authors. For the broader benefit of current researchers, educators in higher education, and academic bodies such as associations, publishers, librarians, and companies, we provide chemistry-specific recommendations and summarize the resulting conclusions
Size Dependence of Metal-Insulator Transition in Stoichiometric Fe3O4 Nanocrystals
Magnetite (Fe3O4) is one of the most actively studied materials with a famous
metal-insulator transition (MIT), so-called the Verwey transition at around 123
K. Despite the recent progress in synthesis and characterization of Fe3O4
nanocrystals (NCs), it is still an open question how the Verwey transition
changes on a nanometer scale. We herein report the systematic studies on size
dependence of the Verwey transition of stoichiometric Fe3O4 NCs. We have
successfully synthesized stoichiometric and uniform-sized Fe3O4 NCs with sizes
ranging from 5 to 100 nm. These stoichiometric Fe3O4 NCs show the Verwey
transition when they are characterized by conductance, magnetization, cryo-XRD,
and heat capacity measurements. The Verwey transition is weakly size-dependent
and becomes suppressed in NCs smaller than 20 nm before disappearing completely
for less than 6 nm, which is a clear, yet highly interesting indication of a
size effect of this well-known phenomena. Our current work will shed new light
on this ages-old problem of Verwey transition.Comment: 18 pages, 4 figures, Nano Letters (accepted
Group Additivity for Thermochemical Property Estimation of Lignin Monomers on Pt(111)
Conversion of biomass
has received considerable attention, but
theoretical investigation is challenging due to the large computational
burden. In this contribution, we explore group additivity for computing
the thermochemistry of lignin monomers, and by extension to single-ring
aromatic hydrocarbons, on Pt(111). We find that the previous framework
developed for open-chain molecules and furanics is inadequate for
lignin monomers due to conjugation. Using quantum theory of atoms
in molecules (QTAIM), we find that the type of binding of the adsorbate
atoms with the surface sites, for example, Ï, ÏÏ,
or ÏÏ, has an important impact on the conjugation of bonds
in adsorbates. We introduce two new models that account for the type
of binding of the central atom and its nearest neighbors, namely,
a conjugation-based and a site-based scheme, which result in significant
improvement. A total of 591 density functional theory data points
were regressed; cross-validation of the site-based scheme reveals
that mean absolute errors are 2.81 kcal/mol in Î<i>H</i><sub>f,298</sub>, 1.07 cal/(mol K) in Î<i>S</i><sub>298</sub>, and 0.25 cal/(mol K) in <i>C</i><sub>p,300</sub>. The slightly simpler conjugation-based model, which does not resolve
the binding type of all nearest neighbors, also performs well
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