[Figure see text].[Figure see text].Proper timing of critical care nutrition has long been a matter of controversy. Critical illness waxes and wanes in stages, creating a dynamic flux in energy needs that we have only begun to examine. Furthermore, response to nutrition support likely differs greatly at the level of the individual patient in regard to genetic status, disease stage, comorbidities, and more. We review the observational and randomized literature concerning timing in nutrition support, discuss mechanisms of harm in feeding critically ill patients, and highlight the role of precision nutrition for moving the literature beyond the realm of blunt population averages into one that accounts for the patient-specific complexities of critical illness and host genetics. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http//www.annualreviews.org/page/journal/pubdates for revised estimates.We report on the experimental demonstration of atomically thin molybdenum disulfide (MoS2)-graphene van der Waals (vdW) heterostructure nanoelectromechanical resonators with ultrawide frequency tuning. With direct electrostatic gate tuning, these vdW resonators exhibit exceptional tunability, in general, Δf/f0 > 200%, for continuously tuning the same device and the same mode (e.g., from ∼23 to ∼107 MHz), up to Δf/f0 ≈ 370%, the largest fractional tuning range in such resonators to date. This remarkable electromechanical resonance tuning is investigated by two different analytical models and finite element simulations. Furthermore, we carefully perform clear control experiments and simulations to elucidate the difference in frequency tuning between the heterostructure and single-material resonators. At a given initial strain level, the tuning range depends on the two-dimensional (2D) Young's moduli of the constitutive crystals; devices built on materials with lower 2D moduli show wider tuning ranges. This study exemplifies that vdW heterostructure resonators can retain unconventionally broad, continuous tuning, which is promising for voltage-controlled, tunable nanosystems.Ecdysteroids act as molting hormones in insects and as nonhormonal anabolic agents and adaptogens in mammals. A wide range of ecdysteroid-containing herbal extracts are available worldwide as food supplements. The aim of this work was to study such an extract as a possible industrial source of new bioactive ecdysteroids. A large-scale chromatographic isolation was performed from an extract of Cyanotis arachnoidea roots. Ten ecdysteroids (1-10) including eight new compounds were isolated and characterized by extensive nuclear magnetic resonance studies. https://www.selleckchem.com/products/leupeptin-hemisulfate.html Highly unusual structures were identified, including a H-14β (1, 2, 4, and 10) moiety, among which a 14β(H)17β(H) phytosteroid (1) is reported for the first time. Compounds with an intact side chain (4-10) and 11 other natural or semisynthetic ecdysteroids (11-21) were tested for insect ecdysteroid receptor (EcR) binding activity. Two new compounds, i.e., 14-deoxydacryhainansterone (5) and 22-oxodacryhainansterone (6), showed strong EcR binding activity (IC50 = 41.7 and 380 nM, respectively). Six compounds were identified as EcR agonists and another two as antagonists using a transgenic ecdysteroid reporter gene assay. The present results demonstrate that commercial C. arachnoidea extracts are rich in new, unusual bioactive ecdysteroids. Because of the lack of an authentic plant material, the truly biosynthetic or artifactual nature of these compounds cannot be confirmed.A new method for converting terminal epoxides and primary alcohols into α-alkylated ketones under borrowing hydrogen conditions is reported. The procedure involves a one-pot epoxide ring opening and alkylation via primary alcohols in the presence of an N-heterocyclic carbene iridium(I) catalyst, under aerobic conditions, with water as the side product.The first switchable α-olefination and α-alkylation of nitriles with primary alcohols catalyzed by a well-defined base transition-metal Co complex was presented. A broad variety of nitriles and primary alcohols are selectively and efficiently converted to the corresponding products by this method. It is noteworthy that the transformation is environmentally benign and atom efficient with H2 and H2O being the sole byproducts.Protein self-assembly plays an important role in cellular processes. Whereas molecular dynamics (MD) represents a powerful tool in studying assembly mechanisms, its predictions depend on the accuracy of underlying force fields, which are known to overly promote protein assembly. We here examine villin headpiece domain, HP36, which remains soluble at concentrations amenable to MD studies. The experimental characterization of soluble HP36 at concentrations of 0.05 to 1 mM reveals concentration-independent 90% monomeric and 10% dimeric populations. Extensive all-atom MD simulations at two protein concentrations, 0.9 and 8.5 mM, probe the HP36 dimer population, stability, and kinetics of dimer formation within two MD force fields, Amber ff14SB and CHARMM36m. MD results demonstrate that whereas CHARMM36m captures experimental HP36 monomer populations at the lower concentration, both force fields overly promote HP36 association at the higher concentration. Moreover, contacts stabilizing HP36 dimers are force-field-dependent. CHARMM36m produces consistently higher HP36 monomer populations, lower association rates, and weaker dependence of these quantities on the protein concentration than Amber ff14SB. Nonetheless, the highest monomer populations and dissociation constants are observed when the TIP3P water model in Amber ff14SB is replaced by TIP4P/2005, showcasing the critical role of the water model in addressing the protein solubility problem in MD.We report a bimodal imaging method that can spatially resolve and concurrently correlate SERS and background-free Mie scattering signals. By examining two types of nanoparticle assemblies with different types of plasmonic junctions, namely raspberry-like metamolecules (raspberry-MMs) containing intraparticle nanogaps and groups of Au nanocubes forming interparticle gaps, we were able to rapidly screen SERS-active particles among the entire population of nanoparticles. Ratiometric analysis of SERS/Mie scattering revealed distinct behaviors for these intra- and interparticle nanogaps. In particular, raspberry-MMs showed a high fraction of SERS-active particles with the SERS intensity essentially insensitive to the nanoparticle aggregation state and a predictable environmental dependence. In comparison, nanocube clusters exhibited highly heterogeneous SERS/Mie scattering ratios and unpredictable intensity fluctuations but higher maximum SERS intensity. This dual-imaging approach constitutes an in situ visualization tool that enables simultaneous and stoichiometric analysis of dual signals consisting of elastic and inelastic scattering, which can significantly improve the reliability of SERS measurements.