Synthetic Approach to the Natural -Nitrosohydroxylamino Tetramic Acid JBIR-141.

An analogue of the metabolite JBIR-141, featuring a delicate -nitrosohydroxylamine, a 3-acyltetramic acid, and an oxazoline, was synthesized by a convergent strategy from l-alanine, l-threonine, and l-glutamic acid. Key steps were the cyclization of an Ala-Thr derivative to give the oxazoline, a Dieckmann condensation affording the 3-acyltetramic acid, and the -nitrosation of a hydroxylamino derivative of glutamic acid. An adequate protecting group strategy was established for coupling the three building blocks.

Evaluation of Polyethylene Terephthalate Powder in High Speed Sintering.

Laser Sintering (LS) was the first Powder Bed Fusion (PBF) method for polymers and it is now quite an established process for rapid prototyping and even for the production of functional parts. High Speed Sintering (HSS) is a variant of PBF which was later developed and it has the potential to be more scalable than LS. Most of the work for HSS and LS has been conducted with polyamide-12 (PA 12).

Synthesis and Bioactivity of Ophiofuranones A and B.

Ophiofuranones A and B, metabolites of the fungus , were synthesized in 16 steps and 12%/22% yield. The stereogenic centers were established by Sharpless dihydroxylations and epoxidation, the 1,3-dienes via Wittig or HWE olefinations. The rings were closed through Knoevenagel-type condensation and lactonization.

Investigations on Epoxy-Carbamate Foams Modified with Different Flame Retardants for High-Performance Applications.

In transport sectors such as aviation, automotive and railway, materials combining a high lightweight potential with high flame retardant properties are in demand. Polymeric foams are suitable materials as they are lightweight, but often have high flammability. This study focuses on the influence of different flame retardants on the burning behavior of Novolac based epoxy foams using Isophorone Diamine carbamate (B-IPDA) as dual functional curing and blowing agent.

Mechanical adaptation of brachiopod shells via hydration-induced structural changes.

The function-optimized properties of biominerals arise from the hierarchical organization of primary building blocks. Alteration of properties in response to environmental stresses generally involves time-intensive processes of resorption and reprecipitation of mineral in the underlying organic scaffold. Here, we report that the load-bearing shells of the brachiopod Discinisca tenuis are an exception to this process.

New Insights on Expandability of Pre-Cured Epoxy Using a Solid-State CO-Foaming Technique.

Foaming an epoxy is challenging because the process involves the curing reaction of epoxy and hardener (from monomer to oligomer, to a gel and a final three-dimensional crosslinked network) and the loading of gas phase into the epoxy phase to develop the cellular structure. The latter process needs to be carried out at the optimum curing stage of epoxy to avoid cell coalescence and to allow expansion. The environmental concern regarding the usage of chemical blowing agent also limits the development of epoxy foams.

Prenatal exposure to triclosan induced brain telomere shortening in a wild bird species.

Exposure to the antimicrobial agent Triclosan (TCS) induces oxidative stress in diverse organisms, including birds. However, whether TCS-induced oxidative stress effectively translates into detrimental effects is still unclear. The present study examined whether prenatal TCS exposure induces oxidative stress and telomere shortening in the brain and the liver of near-term embryos of the yellow-legged gull (Larus michahellis).

Magnetic NiFe O Nanoparticles Prepared via Non-Aqueous Microwave-Assisted Synthesis for Application in Electrocatalytic Water Oxidation.

Phase-pure spinel-type magnetic nickel ferrite (NiFe O ) nanocrystals in the size range of 4 to 11 nm were successfully synthesized by a fast and energy-saving microwave-assisted approach. Size and accessible surface areas can be tuned precisely by the reaction parameters. Our results highlight the correlation between size, degree of inversion, and magnetic characteristics of NiFe O nanoparticles, which enables fine-tuning of these parameters for a particular application without changing the elemental composition.

Tailoring Epoxy Resin Foams by Pre-Curing with Neat Amine Hardeners and Its Derived Carbamates.

The use of amine-based carbamates with their dual function, acting as amine curing agents and CO blowing agents after their decomposition without by-products, are promising for ecofriendly epoxy foams as high-performance materials. However, controlling cell morphology requires a proper adjustment of the viscosity at the foaming step. The viscosity is altered not only by blending neat amine and its derived carbamate at a fixed pre-curing time, but also by changing the pre-curing time at a fixed blend ratio.

Kinked Bisamides as Efficient Supramolecular Foam Cell Nucleating Agents for Low-Density Polystyrene Foams with Homogeneous Microcellular Morphology.

Polystyrene foams have become more and more important owing to their lightweight potential and their insulation properties. Progress in this field is expected to be realized by foams featuring a microcellular morphology. However, large-scale processing of low-density foams with a closed-cell structure and volume expansion ratio of larger than 10, exhibiting a homogenous morphology with a mean cell size of approximately 10 µm, remains challenging.

Impact of Antimony(V) on Iron(II)-Catalyzed Ferrihydrite Transformation Pathways: A Novel Mineral Switch for Feroxyhyte Formation.

The environmental mobility of antimony (Sb) is controlled by interactions with iron (Fe) oxides, such as ferrihydrite. Under near-neutral pH conditions, Fe(II) catalyzes the transformation of ferrihydrite to more stable phases, thereby potentially altering the partitioning and speciation of associated Sb. Although largely unexplored, Sb itself may also influence ferrihydrite transformation pathways.

Synthesis of the Proposed Isomers of the Deep-Sea Mussel Metabolites Bathymodiolamides A and B.

The first total synthesis of bathymodiolamides A and B, ceramide-like metabolites of the deep-sea hydrothermal vent mussel , was accomplished in eight linear steps starting from Garner's aldehyde and three carboxylic acids. A sequence of vinylation of Garner's aldehyde, N-acylation with lauric acid, dihydroxylation of the terminal alkene, and stepwise Steglich-Hassner esterifications of the resulting vicinal diol with the respective saturated and unsaturated carboxylic acids, which had to be prepared separately, afforded the target products in 38 and 39% yield. We found distinct discrepancies between their NMR data and antiproliferative activities and those reported for the natural isolates.

Macrooxazoles A-D, New 2,5-Disubstituted Oxazole-4-Carboxylic Acid Derivatives from the Plant Pathogenic Fungus .

In our ongoing search for new bioactive fungal metabolites, four previously undescribed oxazole carboxylic acid derivatives (-) for which we proposed the trivial names macrooxazoles A-D together with two known tetramic acids (-) were isolated from the plant pathogenic fungus . Their structures were elucidated based on high-resolution mass spectrometry (HR-MS) and nuclear magnetic resonance (NMR) spectroscopy. The hitherto unclear structure of macrocidin Z () was also confirmed by its first total synthesis.

Low-Density Polybutylene Terephthalate Foams with Enhanced Compressive Strength via a Reactive-Extrusion Process.

Due to their appealing properties such as high-temperature dimensional stability, chemical resistance, compressive strength and recyclability, new-generation foams based on engineering thermoplastics such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) have been gaining significant attention. Achieving low-density foams without sacrificing the mechanical properties is of vital importance for applications in the field of transportation and construction, where sufficient compressive strength is desired. In contrast to numerous research studies on PET foams, only a limited number of studies on PBT foams and in particular, on extruded PBT foams are known.

Identification of critical areas and evaluation of best management practices using SWAT for sustainable watershed management.

Identification of critical erosion-prone areas and selection of best management practices (BMPs) for watersheds are necessary to control their degradation by reducing sediment yields. The current research assesses and proposes a combination of potential BMPs for the Baitarani catchment in India using the Soil and Water Assessment Tool (SWAT). After the successful calibration and validation of the SWAT model developed for this catchment, the model was applied to evaluate the efficacy of eight agricultural and structural management practices and their combinations (three scenarios) for controlling sediment yields at watershed and sub-watershed levels as well as to assess the impacts of combined BMPs on water balance components.

Antitumoral effects of mitochondria-targeting neutral and cationic cis-[bis(1,3-dibenzylimidazol-2-ylidene)Cl(L)]Pt(ii) complexes.

Recently, we opened a synthetic access to antitumoral platinum complexes of the type cis-[(NHC)1(NHC)2PtIICl(L)] which interact with DNA in a way correlated to the complex charge and to the sterical accessibility of the leaving chlorido ligand. We now identified mitochondria rather than nuclei as the cellular target of the neutral dichlorido complex 1 (L = Cl) and the delocalized lipophilic cationic phosphine complex 2 (L = PPh3), both carrying the same cis-bis(1,3-dibenzylimidazol-2-ylidene) ligands. Their uptake into 518A2 melanoma cells was concentration-dependent and distinctly greater for complex 2 which was also more cytotoxic against sensitive cancer cell lines with submicromolar IC50 values.

Photoinduced Defect and Surface Chemistry of Niobium Tellurium Oxides ANbTeO (A = K, Rb, Cs) with Defect-Pyrochlore Structure.

The niobium tellurium oxides ANbTeO with varying A cations (A = K, Rb, Cs) and defect-pyrochlore crystal structure were used to investigate the effect of A on crystal-structure deformation and defect-chemistry. We show that the light absorption of these compounds in visible light is due to defects and not the effect of a low band gap. Using the materials in photocatalytic hydrogen generation, the prevailing defects and the surface composition change significantly during photocatalytic hydrogen evolution.

Phenotypic plasticity of senescence in under predation impact: no ageing acceleration when the perceived risk decreases with age.

Recognising the nature of the predation risk, and responding to it accurately, is crucial to fitness. Yet, even the most accurate adaptive responses to predation risk usually entail costs, both immediate and lifelong. Rooting in life-history theory, we hypothesize that an animal can perceive the nuances of prey size and age selectivity by the predator and modulate its life history accordingly.

N-Metallocenoylsphingosines as targeted ceramidase inhibitors: Syntheses and antitumoral effects.

Three N-metallocenoylsphingosines with variance in the central metal (Fe, Co, Ru), the charge (neutral or cationic), and the arene ligands (Cp, Cp*Ph) were synthesized from serine and metallocene carboxylic acids as substrate-analogous inhibitors of human acid ceramidase (AC). Their inhibitory potential was examined using the recombinant full length ASAH1 enzyme, expressed and secreted from High Five insect cells, and the fluorescent substrate Rbm14-12. All complexes inhibited AC, most strongly so ruthenium(II) complex 13a.

Antimony and arsenic speciation, redox-cycling and contrasting mobility in a mining-impacted river system.

The Macleay River in eastern Australia is severely impacted by historic stibnite- and arsenopyrite-rich mine-tailings. We explore the partitioning, speciation, redox-cycling, mineral associations and mobility of antimony and arsenic along >70 km reach of the upper Macleay River. Elevated Sb/As occur throughout the active channel-zone and in floodplain pockets up to the regolith margin, indicating broad dispersal during floods.

Synthesis and bioevaluation of new vascular-targeting and anti-angiogenic thieno[2,3-d]pyrimidin-4(3H)-ones.

A series of forty-six 5,6-annulated 2-arylthieno [2,3-d]pyrimidin-4(3H)-ones were prepared as potentially pleiotropic anticancer drugs with variance in the tubulin-binding trimethoxyphenyl motif at C-2 of a thieno [2,3-d]pyrimidine fragment, enlarged by additional rings of different size and substitution. By assessing their cytotoxicity against various cancer cells, their influence on the polymerization of neat tubulin and the dynamics of microtubule and F-actin cytoskeletons, and their vascular-disrupting and anti-angiogenic activities in vitro and in vivo, structure-activity relations were identified which suggest the 3-iodo-4,5-dimethoxyphenyl substituted thienopyrimidine 2e as a promising anticancer drug candidate for further research. 2020 Elsevier Ltd.

Keeping the shoot above water - submergence triggers antithetical growth responses in stems and petioles of watercress (Nasturtium officinale).

The molecular mechanisms controlling underwater elongation are based extensively on studies on internode elongation in the monocot rice (Oryza sativa) and petiole elongation in Rumex rosette species. Here, we characterize underwater growth in the dicot Nasturtium officinale (watercress), a wild species of the Brassicaceae family, in which submergence enhances stem elongation and suppresses petiole growth. We used a genome-wide transcriptome analysis to identify the molecular mechanisms underlying the observed antithetical growth responses.

Synthesis, structures and cytotoxic effects in vitro of cis- and trans-[PtCl(NHC)] complexes and their Pt precursors.

Four new bis(N,N-dialkylbenzimidazol-2-ylidene)dichlorido platinum(ii) complexes 2 featuring N-alkyl substituents of increasing size (a: Me, b: Et, c: n-butyl, d: n-octyl) were synthesised and oxidised with PhICl to give the corresponding [PtCl(N,N-dialkylbenzimidazol-2-ylidene)] complexes 4 as potential anticancer prodrugs. The known bis(N,N-dibenzylimidazol-2-ylidene)dichlorido platinum(ii) complex 1 was likewise oxidised to [PtCl(N,N-dibenzylimidazol-2-ylidene)] 3. In contrast, oxidation of complexes 1 and 2 with HO or hypochlorites, or exchange of chlorido for hydroxo ligands in tetrachlorido complexes 4 failed to give isolable complexes of type [PtCl(OH)(NHC)].

Luminescent Gold(I) Complexes of 1-Pyridyl-3-anthracenylchalcone Inducing Apoptosis in Colon Carcinoma Cells and Antivascular Effects.

The luminescent chalcone gold(I) conjugates [Au(PPh)(AN3)]PF() and [Au(SIMes)(AN3)]PF () (AN3 = ()-3-(9-anthracenyl)-1-(4-pyridyl)propenone; SIMes = ,'-dimesitylimidazolidin-2-ylidene; Mes = 2,4,6-trimethylphenyl)) were prepared and characterized; complex was also characterized by X-ray crystallography. In MTT assays against a panel of three human colon, a melanoma and a breast cancer cell lines both complexes were antiproliferative with low micromolar IC values. It is noteworthy that HCT116 colon carcinoma cells lacking functional p53 (a vital tumor suppressor) were more susceptible to them than the wildtype parent cell line.

Single-crystal diffractometer coupled with double-sided laser heating system at the Extreme Conditions Beamline P02.2 at PETRAIII.

Combination of in situ laser heating with single-crystal X-ray diffraction (scXRD) in diamond anvil cells (DACs) provides a tool to study crystal structures and/or chemistry of materials at simultaneous high pressures and high temperatures. Here, we describe the first dedicated single-crystal X-ray diffractometer coupled with double-sided laser heating (dsLH) system. The scXRD/dsLH setup was developed for the P02.