Negative thermal expansion is known to exist in a range of structure types but is extremely rare in hexagonal perovskites. Here we demonstrate that BaIrO displays negative linear thermal expansion in the direction of its face-shared IrO trimers, and apparent zero volume thermal expansion below 100 K. We present evidence that this anomalous thermal expansion is driven by an unusual form of rigid body phonon behaviour governed by the effective trimer valence state and therefore has structural and electronic components to the underlying mechanism.
View Article and Find Full Text PDFIce XIX is a partly hydrogen-ordered polymorph related to disordered ice VI, similar to ice XV. We here investigate the order-order-disorder sequence ice XIX→ice XV→ice VI based on calorimetry at ambient pressure both for DO and HO-ice XIX. From these data we extract configurational entropy differences between ice XIX, ice XV and ice VI.
View Article and Find Full Text PDFViticulture and associated products are an important part of the economy in many countries. However, biotic and abiotic stresses impact negatively the production of grapes and wine. Climate change is in many aspects increasing both these stresses.
View Article and Find Full Text PDFThe classical view of the structural changes that occur at the ferroelectric transition in perovskite-structured systems, such as BaTiO, is that polarization occurs due to the off-center displacement of the B-site cations. Here, we show that in the bismuth sodium titanate (BNT)-based composition 0.2(BaSrTiO)-0.
View Article and Find Full Text PDFLow temperature ionic conducting materials such as OH and H ionic conductors are important electrolytes for electrochemical devices. Here we show the discovery of mixed OH/H conduction in ceramic materials. SrZrYO exhibits a high ionic conductivity of approximately 0.
View Article and Find Full Text PDFThe plant-specific family of GRAS transcription factors has been wide implicated in the regulation of transcriptional reprogramming associated with a diversity of biological functions ranging from plant development processes to stress responses. Functional analyses of GRAS transcription factors supported by o structural and comparative analyses are emerging and clarifying the regulatory networks associated with their biological roles. In this review, a detailed analysis of GRAS proteins' structure and biochemical features as revealed by recent discoveries indicated how these characteristics may impact subcellular location, molecular mechanisms, and function.
View Article and Find Full Text PDFNatural products belonging to different chemical classes have been established as a promising source of novel anticancer drugs. Several low-molecular-weight compounds from the classes of monoterpenes, phenylpropanoids, and flavonoids were shown to possess anticancer activities in previous studies. In this work, over 20 semisynthetic derivatives of molecules belonging to these classes, namely thymol, eugenol, and 6-hydroxyflavanone were synthesized and tested for their cytotoxicity against two human cancer cell lines, namely AGS cells (gastric adenocarcinoma) and A549 cells (human lung carcinoma).
View Article and Find Full Text PDFThe Spodoptera complex of the family Noctuidae, represented here by S. frugiperda (J.E.
View Article and Find Full Text PDFBackground: Planning for vascular access (VA) creation is essential in pre-dialysis patients although optimal timing for VA referral and placement is debatable. Guidelines suggest referral when eGFR is 15-20 mL/min/1.73 m.
View Article and Find Full Text PDFThe structure and vibrational spectroscopy of centrohexaindane, 1, was investigated. This unusual molecule has a quaternary carbon atom that is coordinated to four further such quaternary carbon atoms as its core, each pair of which is bonded to an ortho-phenylene unit. Previous NMR studies have shown that the molecule has tetrahedral (T ) symmetry in solution.
View Article and Find Full Text PDFBackground: Reliable vascular access (VA) is required for patients receiving chronic hemodialysis (HD) treatment. Vascular mapping using duplex doppler ultrasonography (DUS) can aid in planning VA construction. Greater handgrip strength (HGS) was found to be associated with more developed distal vessels both in chronic kidney disease (CKD) patients and healthy individuals, and patients with lower HGS had worse morphologic vessel characteristics and were, therefore, less likely to construct distal VA.
View Article and Find Full Text PDFis responsible for the gray mold disease, severely affecting grapevine and hundreds of other economically important crops. However, many mechanisms of this fruit-pathogen interaction remain unknown. The combined analysis of the transcriptome and metabolome of green fruits infected with from susceptible and tolerant genotypes was never performed in any fleshy fruit, mostly because green fruits are widely accepted to be resistant to this fungus.
View Article and Find Full Text PDFAntiferroelectric (AFE) materials have been intensively studied due to their potential uses in energy storage applications and energy conversion. These materials are characterized by double polarization-electric field (-) hysteresis loops and nonpolar crystal structures. Unusually, in the present work, SrLaTaTiO (STLT32), SrLaTaTiO (STLT36), and SrCaTaO (SCT15), lead-free perovskite layered structure (PLS) materials, are shown to exhibit AFE-like double - hysteresis loops despite maintaining a polar crystal structure.
View Article and Find Full Text PDFA recently synthesized new eugenol derivative, ethyl 4-(2-methoxy-4-(oxiran-2-ylmethyl)phenoxy)butanoate, with a high insecticidal activity against () insect cells, was encapsulated in the liposomal formulations of egg-phosphatidylcholine/cholesterol (Egg-PC:Ch) 70:30 and 100% dioleoylphosphatidylglycerol (DOPG), aiming at the future application as insecticides. Compound-loaded DOPG liposomes have sizes of 274 ± 12 nm, while Egg-PC:Ch liposomes exhibit smaller hydrodynamic diameters (69.5 ± 7 nm), high encapsulation efficiency (88.
View Article and Find Full Text PDFThe aim of this work was to produce filaments of PLA/PBAT and NPK fertilizer adsorbed on organophilized bentonite intended for application in the prototyping of biodegradable agricultural artifacts in 3D printing, using the Fused Deposition Modeling (FDM) technique. This is the first time that we have reported this composite for a 3D printing approach. Systems containing PLA/PBAT, organobentonite and NPK were initially processed in an internal mixer and later extruded as filaments in a single-screw extruder.
View Article and Find Full Text PDFWe have re-investigated the structure and vibrational spectroscopy of the iconic molecule iron pentacarbonyl, Fe(CO), in the solid state by neutron scattering methods. In addition to the known 2/ structure, we find that Fe(CO) undergoes a displacive ferroelastic phase transition at 105 K to a 1̅ structure. We propose that this is a result of certain intermolecular contacts becoming shorter than the sum of the van der Waals radii, resulting in an increased contribution of electrostatic repulsion to these interactions; this is manifested as a strain that breaks the symmetry of the crystal.
View Article and Find Full Text PDFGrapevine is regarded as a highly profitable culture, being well spread worldwide and mostly directed to the wine-producing industry. Practices to maintain the vineyard in healthy conditions are tenuous and are exacerbated due to abiotic and biotic stresses, where fungal grapevine trunk diseases (GTDs) play a major role. The abolishment of chemical treatments and the intensification of several management practices led to an uprise in GTD outbreaks.
View Article and Find Full Text PDFNon-canonical secretion pathways, collectively known as unconventional protein secretion (UPS), are alternative secretory mechanisms usually associated with stress-inducing conditions. UPS allows proteins that lack a signal peptide to be secreted, avoiding the conventional endoplasmic reticulum-Golgi complex secretory pathway. Molecules that generally rely on the canonical pathway to be secreted may also use the Golgi bypass, one of the unconventional routes, to reach the extracellular space.
View Article and Find Full Text PDFActa Crystallogr B Struct Sci Cryst Eng Mater
June 2022
Experimental and computational studies of ammonium carbamate have been carried out, with the objective of studying the elastic anisotropy of the framework manifested in (i) the thermal expansion and (ii) the compressibility; furthermore, the relative thermodynamic stability of the two known polymorphs has been evaluated computationally. Using high-resolution neutron powder diffraction data, the crystal structure of α-ammonium carbamate (ND·NDCO) has been refined [space group Pbca, Z = 8, with a = 17.05189 (15), b = 6.
View Article and Find Full Text PDFCabo Verde's biodiversity is threatened by activities that meet human needs. To counteract this, an integration of scientific and indigenous knowledge is required, but no comprehensive list of the useful local plants is available. Thus, in this work, we assess (1) their diversity and phytogeography; (2) the role of geophysical, historical, and socio-economic factors on species distribution and uses; and (3) potentially relevant species for sustainable development.
View Article and Find Full Text PDFNew compounds with potential insecticide activity were synthesized by structural modifications performed in the monoterpenoid phenolic moieties of carvacrol and thymol, resulting in a set of derivatives with the ether function containing the propyl, chloropropyl or hydroxypropyl chains, as well as a bicyclic ether with an unsaturated chain containing a carboxylic acid terminal. In addition, an analogue of carvacrol and thymol isomers bearing methoxyl, 1-hydroxyethyl and (3-chlorobenzoyl)oxy, instead of the three original methyl groups, was also synthesized. Several structural changes that resulted in diminished insecticide activity have been identified, but two significantly active molecules have been synthesized, one of them being less toxic to human cells than the naturally-derived starting materials.
View Article and Find Full Text PDFEugenol, 4-allyl-2-methoxyphenol, is the main constituent of clove essential oil and has demonstrated relevant biological activity, namely anticancer activity. Aiming to increase this activity, we synthesized a series of eugenol β-amino alcohol and β-alkoxy alcohol derivatives, which were then tested against two human cancer cell lines, namely gastric adenocarcinoma cells (AGS) and lung adenocarcinoma cells (A549). An initial screening was performed to identify the most cytotoxic compounds.
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