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High-amylose maize starch (HAS) was used to produce a fibrous 3D network nanosystem aiming at providing an efficient and stable emulsion stabilizer characterized by being robust against storage, freeze-thawing, high temperatures and mechanical shearing. This approach is principally different from the usually applied stabili-zation systems based on surfactants or small solid particles. Here, we utilized a sodium hydroxide-based low -temperature, chemical gelatinization protocol to minimize molecular degradation, and ethanol nanoprecipitation to reassociate the polysaccharides nanoparticles (NPs) to form a 3D nanosystem. Octenyl succinic anhydride (OSA) substitution was used for modulation of the amphipathic properties of the nanosystem to enhance the emulsfying capacity. With increased OSA substitution, light transmittance of the NPs solutions increased and the size distribution of the NPs decreased down to 100 nm. The obtained emulsions were characterized by being water in oil (W/O) systems, and the NPs were distributed in the oil phase. OSA substitution and NPs concen-tration contributed combinedly to the emulsification capacity. The nanosystem, at 5% concentration with 20% OSA modification, had droplets of approximately 1 mu m in diameter, and could withstand a 60-day-long storage, five-cycle freeze-thaw and thermal stability tests. In addition, it also displayed higher mechanical stabilities to shear-thinning.

This research experimentally measured the solubility of 2-aminoterephthalic acid in eight pure alcoholic solvents - methanol, ethanol, 1-propanol, 1-butanol, 2-propanol, 2-butanol, 2-methyl-2-propanol, and 3-methyl-1-butanol - from 303.15 to 338.15 K at normal pressure p = 0.1 MPa by the excess solid method. The measured solubility of 2-aminoterephthalic acid in these pure organic solvents was found to increase with the rise of temperature in the following order: 3-methyl-1-butanol (lowest solubility) < 1-butanol < 2-butanol < 1-propanol < 2-methyl-2-propanol approximate to 2-propanol < ethanol < methanol (highest solubility). The experimental solubility was correlated by the Van't Hoff equation and the lambda h (Buchowski) equation. The apparent thermo-dynamic properties (Delta 0Gsol, Delta 0Hsol and Delta 0Ssol) were calculated by the Van't Hoff equation, from which it was concluded that the dissolution process is entropy-motivated and endothermal. In addition, the solvent effects on 2-aminoterephthalic acid solubility were studied by the KAT-LSER model, where the results showed that the polarizability accounts for 47.9 +/- 4.2 % of the total solvent effect.A volcano-type relation between the dissolution entropy and enthalpy versus the solvent boiling point is re-ported, showing maximal values of 55.3 J mol-1 K-1 and 29.2 kJ mol-1, respectively, for intermediate molecular interactions of solute and solvent.

Graphical abstract Hydroxychloroquine (HCQ) and favipiravir (FPV) are known to be effective antivirals, and there are reports about their use to fight the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) despite that these are not conclusive. The use of combined drugs is common in drug discovery, and thus, we investigated HCQ and FPV as a combined drug. The density functional theory method was used for the optimization of geometries, spectroscopic analysis and calculation of reactivity parameters. The quantum theory of atoms in molecules was applied to explain the nature of the hydrogen bonds and confirm the higher stability of the combined drug. We also evaluated the absorption, distribution, metabolism and excretion (ADME) parameters to assess their drug actions jointly using SwissADME. The preliminary findings of our theoretical study are promising for further investigations of more potent and selective antiviral drugs. Supplementary Information The online version contains supplementary material available at 10.1007/s11696-021-01946-8.

Huntington's disease is a progressive neurodegenerative disease caused by expansion of the polyglutamine domain in the first exon of huntingtin (HttEx1). The extent of expansion correlates with disease progression and formation of amyloid-like protein deposits within the brain. The latter display polymorphism at the microscopic level, both in cerebral tissue and in vitro. Such polymorphism can dramatically influence cytotoxicity, leading to much interest in the conditions and mechanisms that dictate the formation of polymorphs. We examine conditions that govern HttEx1 polymorphism in vitro, including concentration and the role of the non-polyglutamine flanking domains. Using electron microscopy, we observe polymorphs that differ in width and tendency for higher-order bundling. Strikingly, aggregation yields different polymorphs at low and high concentrations. Narrow filaments dominate at low concentrations that may be more relevant in vivo. We dissect the role of N- and C-terminal flanking domains using protein with the former (httNT or N17) largely removed. The truncated protein is generated by trypsin cleavage of soluble HttEx1 fusion protein, which we analyze in some detail. Dye binding and solid-state NMR studies reveal changes in fibril surface characteristics and flanking domain mobility. Higher-order interactions appear facilitated by the C-terminal tail, while the polyglutamine forms an amyloid core resembling those of other polyglutamine deposits. Fibril-surface-mediated branching, previously attributed to secondary nucleation, is reduced in absence of httNT. A new model for the architecture of the HttEx1 filaments is presented and discussed in context of the assembly mechanism and biological activity.

Several fully pi-conjugated macrocycles with puckered or cage-type structures were recently found to exhibit aromatic character according to both experiments and computations. We examine their electronic structures and put them in relation to 3D-aromatic molecules (e.g., closo-boranes) and to 2D-aromatic polycyclic aromatic hydrocarbons. Using qualitative theory combined with quantum chemical calculations, we find that the macrocycles explored hitherto should be described as 2D-aromatic with three-dimensional molecular structures (abbr. 2D-aromatic-in-3D) and not as truly 3D-aromatic. 3D-aromatic molecules have highly symmetric structures (or nearly so), leading to (at least) triply degenerate molecular orbitals, and for tetrahedral or octahedral molecules an aromatic closed-shell electronic structure with 6n + 2 electrons. Conversely, 2D-aromatic-in-3D structures exhibit aromaticity that results from the fulfillment of Hückel's 4n + 2 rule for each macrocyclic path, yet, their -electron counts are coincidentally 6n + 2 numbers for macrocycles with three tethers of equal lengths. It is notable that 2D-aromatic-in-3D macrocyclic cages can be aromatic with tethers of different lengths, i.e., with p-electron counts different from 6n + 2, and they are related to naphthalene. Finally, we identify tetrahedral and cubic pi-conjugated molecules that fulfill the 6n + 2 rule and exhibit significant electron delocalization. Yet, their properties resemble those of analogous compounds with electron counts that differ from 6n + 2. Thus, despite that these molecules show substantial pi-electron delocalization they cannot be classified as true 3D-aromatics O.E.B. is grateful to the Wenner-Gren Foundations for a postdoctoral fellowship (UPD 2018-0305), and H.O., K.J., and R.A. acknowledge the Swedish Research Council for financial support (grants 2015-04538 and 2019-05618). M.S. is grateful for the financial support from the Spanish MICINN (project PID2020-113711GB-I00) and the Catalan DIUE (project 2017SGR39). D.W.S. acknowledges the financial support by the National Science Centre, Poland (2021/42/E/ST4/ 00332) and the PL-Grid Infrastructure of the Academic Computer Centre (CYFRONET). The computations were enabled by resources provided by the Swedish National Infrastructure for Computing (SNIC) at the National Supercomputer Center (NSC), Linköping, partially funded by the Swedish Research Council through grants 2015-04538 and 2019-05618

N,N '-bis(aniline)glyoxime (H2L, 1) has been prepared from aniline and (E,E)-dichloroglyoxime (DCGO) or (E,E)-dibromoglyoxime (DBGO). The reaction of N,N '-bis(aniline)glyoxime (H2L, 1) with solution of PtCl2 in dimethylsulfoxide produced brown-colored bis(E,E-dioximato)platinum(II) complex {[(E,E)-Pt(HL)(2)]} (1a) featuring N-chelating ligand. The crystal structure of this complex has been identified by X-ray diffraction on a single-crystal. In vitro assay of proliferation, cell death, DNA-damage and cell uptake activities of 1 and 1a were tested in HCC cell lines, SNU-182 and HUH-7. 1a has an anti-proliferative effect in HCC cells, however, 1 did not. Furthermore, the cellular uptake of 1a was relatively high compared to cisplatin cellular platinum levels. Compatible with proliferation and cellular uptake results, treatment with 1a caused DNA-damage and subsequent apoptosis in both HCC cell lines. Research Fund of the Gebze Technical University (BAP) [2018-A108-72] This work was financially supported by Research Fund of the Gebze Technical University (BAP, Project Number: 2018-A108-72).

The effect of the length of main and side chains of high-range water-reducing admixture (HRWRA) on some fresh and hardened properties of self-consolidating concretes (SCCs) was researched. admixtures with different side and main chain lengths were synthesized. For a given SCC slump-flow value, the admixture requirement was the least when the admixture having a medium side chain length (2400 g/mol) was used. Moreover, decreasing the main chain length of the admixture improved the fresh properties' retention of SCC. The fact was attributed to the increase in free polymer in the mixture by increasing the side chain length of the admixture. The main and side chain lengths of the HRWRA admixture were significantly influential on the early compressive strength of SCC mixtures but had a negligible effect on their 7- and 28-day compressive strength and 28-day water absorption., Bursa Uluda University Science and Technology Centre (BAP) [219M425, 2016/16, 2018/9]; TUBITAK [217M408], The authors appreciate contributions of the Scientific and Technological Research Council of Turkey (TUBITAK) and Bursa Uluda University Science and Technology Centre (BAP) under grant numbers 219M425, AYP (MH) -2016/16, and DDP (MH) -2018/9. In addition, the first author would like to acknowledge the scholarship provided by TUBITAK under grant number 217M408 during his PhD study. The authors would like to thank Polisan Construction Chemicals Company and Bursa Ready Mixed Concrete Plant authorities for their kind assistance in providing the cement and water-reducing admixtures, as well as determining their characteristics.

A study of phase transitions of photochromic p,p’-n-alkylazobenzenes compounds was carried out by means of adiabatic scanning calorimetry (ASC) and photopyroelectric calorimetry (PPE) techniques, yielding accurately the temperature dependence of the enthalpy and of the specific heat capacity across the observed phase transitions, and the corresponding enthalpy of transition values. In addition, polarization microscopy imaging of the sample texture was performed together with the PPE calorimetric evaluations to establish the nature of the involved phases. By performing PPE calorimetric evaluations during UV irradiation of the samples, the influence of the photoinduced trans to cis isomerization of the nAB molecules on the occurrence of the phase transitions was assessed.

Direct spectroscopic evidence of a reaction occurring between acrolein and water and involving the exchange of an oxygen atom has been obtained by characterizing the non-covalently bound water complexes and their isotopic forms, via rotational spectroscopy. The experimental geometries of the binary and ternary water complexes have been determined, and other stationary points on the reaction path have been characterized using ab initio quantum chemical methods at the MP2/6-311++G(d,p) level. These results can enhance the understanding of the water-mediated atmospherically important reactions involving acrolein.

While several reviews have been devoted to lower (ethylene and propylene) olefin polymerisation, several other substrates catalysed by vanadium complexes have escaped review. Here, vanadium-based complexes, active as (pre-)catalysts in the polymerisation of higher olefins, ring-opening metathesis polymerisation (ROMP) of alkenes, and ring-opening polymerisation (ROP) of lactones are reviewed. The Ziegler-Natta systems and some oxovanadium and vanadocene single-site pre-catalysts active towards styrene polymerisation are also mentioned. Furthermore, imidovanadium(V) complexes catalysing ROMP with ligands including aryl, aryloxy, and ketimide substituents are thoroughly reviewed and their activities and yields are compared. The ROP of lactides and epsilon-caprolactone is also discussed.

Hydrothermal carbonization (HTC) has become a promising technology for the production of hydrochar and carbon spheres. Several studies indicate a strong dependency of the reaction conditions on the sphere diameter. The usage of additives, such as salts, is one possibility to increase the size of the spheres. However, the growth mechanism which leads to larger particles is not fully understood. In this work, kinetic studies of HTC with fructose were performed with different salts as additives. The growth of the particles (the increase in size) has been compared to the formation rates (increase in yield) of hydrochar by using the reaction rate constants from the kinetic model. The results indicate that the acceleration of the growth rate is independent of the formation rate. It is therefore assumed that coagulation, as a growth mechanism, took place. With longer reaction times, the particles reached a stable particle size, independently from the added salts; therefore, it was assumed that the particles underwent some sort of solidification. The state of matter can therefore be described as an intermediate state between liquid and solid, similar to mesophase pitch. Experiments with a stirrer resulted in squashed particles, which supports the model, that the particles exhibit emulsion-like behavior., Projekt DEAL; Federal Ministry of Education and Research of Germany [01DH17035]; Paul and Yvonne Gillet Foundation, Open Access funding enabled and organized by Projekt DEAL. This research was funded by the Federal Ministry of Education and Research of Germany in the framework of the ERA-Net Medwaste initiative, grant number 01DH17035. Dennis Jung received a generous grant from the Paul and Yvonne Gillet Foundation

The complexity and high sensitivity of proteins to environmental factors give rise to a multitude of variables, which affect the stabilization mechanisms in protein foams. Interfacial and foaming properties of proteins have been widely studied, but the reported unique effect of pH, which can be of great interest to applications, has been investigated to a lesser extent. In this paper, we focus on the impact of pH on the stability of black foam films and corresponding foams obtained from solutions of a model globular protein&mdash, the whey &beta, lactoglobulin (BLG). Foam stability was analyzed utilizing three characteristic parameters (deviation time, transition time and half-lifetime) for monitoring the foam decay, while foam film stability was measured in terms of the critical disjoining pressure of film rupture. We attempt to explain correlations between the macroscopic properties of a foam system and those of its major building blocks (foam films and interfaces), and thus, to identify structure-property relationships in foam. Good correlations were found between the stabilities of black foam films and foams, while relations to the properties of adsorption layers appeared to be intricate. That is because pH-dependent interfacial properties of proteins usually exhibit an extremum around the isoelectric point (pI), but the stability of BLG foam films increases with increasing pH (3&ndash, 7), which is well reflected in the foam stability. We discuss the possible reasons behind these intriguingly different behaviors on the basis of pH-induced changes in the molecular properties of BLG, which seem to be determining the mechanism of film rupture at the critical disjoining pressure.

A thorough characterization of the title compound, (dimim)2[Fe2Cl6(μ-O)], consisting of a (μ-oxido)-bridged binuclear iron(III) complex and 1,3-dimethylimiazolium (dimim) cation, has been performed using a wide range of techniques. The room temperature disordered crystal structure of this compound transits to an incommensurately modulated crystal structure at 100 K; to our knowledge, the first one found for an imidazolium halometallate complex. The crystal structure was solved in the superspace group P 1 ¯ (/α/β/γ)0 with modulation vector q = 0.1370(10) 0.0982(10) 0.326(2) at 100 K. Variable temperature synchrotron powder x-ray diffraction showed the presence of satellite peaks in addition to the main diffraction peaks up to 208 K. Furthermore, a thermal expansion study was performed with this technique from 100 to 383 K (near of its melting point) adressing questions about the nature and consequences of the ion self-assembly of this (μ-oxido)-bridged binuclear iron(III) complex, as well as the molecular motion of the imidazolium cation within the crystalline structure as a response to the temperature effect. Finally, we present a deep magnetic study based on magnetic susceptibility, magnetization and Mössbauer measurements, where the strong antiferromagnetic exchange coupling detected is due to the occurrence of a μ-oxido bridge between the Fe(III), giving rise to an intra-dimeric antiferromagnetic exchange coupling of –308 cm−1.

Flavonoids are used as natural additives and antioxidants in foods, and after coordination to metal ions, as drug candidates, depending on the flavonoid structure. The rate of radical scavenging of the ubiquitous plant flavonoid kaempferol (3,5,7,4'-tetrahydroxyflavone, Kaem) was found to be significantly enhanced by coordination of Mg(II), Ca(II), Sr(II), and Ba(II) ions, whereas the radical scavenging rate of apigenin (5,7,4'-trihydroxyflavone, Api) was almost unaffected by alkaline earth metal (AEM) ions, as studied for short-lived b-carotene radical cations (beta-Car(center dot+)) formed by laser flash photolysis in chloroform/ethanol (7 : 3) and for the semi-stable 2,2-diphenyl-1-picrylhydrazyl radical, DPPH center dot, in ethanol at 25 degrees C. A 1 : 1 Mg(II)-Kaem complex was found to be in equilibrium with a 1 : 2 Mg(II)-Kaem(2) complex, while for Ca(II), Sr(II) and Ba(II), only 1 : 2 AEM(II)-Kaem complexes were detected, where all complexes showed 3hydroxyl and 4-carbonyl coordination and stability constants of higher than 10(9) L-2 mol(-2). The 1 : 2 Ca(II)-Kaem(2) complex had the highest second order rate constant for both beta-Car(center dot+) (5 x 10(8) L mol(-1) s(-1)) and DPPH center dot radical (3 x 10(5) L mol(-1) s(-1)) scavenging, which can be attributed to the optimal combination of the stronger electron withdrawing capability of the (n - 1)d orbital in the heavier AEM ions and their spatially asymmetrical structures in 1 : 2 AEM-Kaem complexes with metal ion coordination of the least steric hindrance of two perpendicular flavone backbones as ligands in the Ca(II) complex, as shown by density functional theory calculations.

In this article, synthesis, characterization and mesomorphic properties of a new calamitic liquid crystal, 2,5-(dimethoxy)-2-[[(4-(dodecyloxy)phenyl)imino]methyl]benzene) (DDPIMB) are described. The phase transition temperatures of the DDPIMB mesomorphic compound have been carried out by differential scanning calorimetry and optical polarizing microscopy. Geometry optimization calculations have been made for the two possible isomers as cis and trans of DDPIMB using the DFT/B3LYP/6-311++G(d,p) level of theory. According to the theoretical calculation results, trans isomerism was found more stable than cis isomerism. Therefore, all theoretical calculations were made for the trans-isomer and compared to the observed results. Vibrational assignments of the observed infrared spectra of title compound were carried out based on the calculated potential energy distributions (PEDs). The electronic properties of the DDPIMB were shown on the TD-DFT/B3LYP level. The optical behavior of the liquid crystal DDPIMB was determined through basic optical parameters, nonlinear optics (NLO) properties and dipole moments. Moreover, frontier molecular orbitals and molecular electrostatic potential (MEP) were determined to define the chemical activity of the headline molecule. The obtained results showed that this liquid crystal is a candidate material that can be used in NLO, optics and optoelectronic technology.

© 2018 Elsevier Ltd In this study, a biphasic reaction system was developed for the microwave-assisted production of 5-hydroxymethylfurfural (HMF) and furfural. The proposed biphasic reaction system is a possible solution in the transition of current industrially state-of-the-art technologies which use C6 carbohydrates to an industrial process where lignocellulosic biomass can be processed, thus being a true sustainable process. In this respect, cellulose and xylan were chosen as model compounds since they are considered as the major building blocks of lignocellulosic polysaccharides. The reaction system consisted of an acidified aqueous phase and methyl isobutyl ketone (MIBK) as the organic phase. Upon the formation of HMF and furfural in the water phase, an instantaneous extraction into MIBK took place. The proposed biphasic reaction system offers many advantages over a monophasic reaction system, including (i) upon formation, furfural and HMF are continuously extracted into the MIBK layer, leading to the suppression of unwanted rehydration reactions, (ii) no unwanted solid particles are formed, and (iii) HMF and furfural can more easily be recovered from the reaction mixture. The goal of this study was to develop the microwave-assisted process in such a way that both cellulose and xylan were simultaneously converted. To this end, optimum process parameters in terms of HCl concentration (cHCl), temperature (T) and reaction time (t) were determined. A maximum HMF yield of 33.65 ± 0.46 w% (or 43.27 mol%) and a maximal furfural yield of 33.30 ± 1.30 w% (or 45.79 mol%) were achieved. To validate the proposed biphasic system, bamboo (Phyllostachys aureosulcata) was applied as a lignocellulosic feedstock, which resulted in a HMF yield of 42.44 mol% and a furfural yield of 48.90 mol%, based upon the cellulose and hemicellulose fraction of the bamboo particles. Since similar yields are observed compared to the model compounds, it is concluded that the lignocellulosic structure does not influence the reaction pathway. This means that the proposed biphasic system can be generalized for a wide variety of lignocellulosic feedstocks. ispartof: Journal of Cleaner Production vol:187 pages:1014-1024 status: published

OBJECTIVE: Aging is accompanied by a series of changes in mature tissues that influence their properties and functions. Collagen, as one of the main extracellular components of cartilage, becomes highly crosslinked during aging. In this study, the aim was to examine whether a correlation exists between collagen crosslinking induced by artificial aging and mechanical properties of the temporomandibular joint (TMJ) condyle. To evaluate this hypothesis, collagen crosslinks were induced using ribose incubation. METHODS: Porcine TMJ condyles were incubated for 7 days with different concentrations of ribose. The compressive modulus and stiffness ratio (incubated versus control) was determined after loading. Glycosaminoglycan and collagen content, and the number of crosslinks were analyzed. Tissue structure was visualized by microscopy using different staining methods. RESULTS: Concomitant with an increasing concentration of ribose, an increase of collagen crosslinks was found. The number of crosslinks increased almost 50 fold after incubation with the highest concentration of ribose. Simultaneously, the stiffness ratio of the samples showed a significant increase after incubation with the ribose. Pearson correlation analyses showed a significant positive correlation between the overall stiffness ratio and the crosslink level; the higher the number of crosslinks the higher the stiffness. CONCLUSION: The present model, in which ribose was used to mimic certain aspects of age-related changes, can be employed as an in vitro model to study age-related mechanical changes in the TMJ condyle. ispartof: Archives of Oral Biology vol:87 pages:102-109 ispartof: location:England status: published

A survey of crystal structures including two organic compounds unable to form hydrogen bonding has been carried out using the Cambridge Structural Database. Such systems are common and numerous. Association modes mostly include stacking of flat systems, one of them usually being an aromatic hydrocarbon. "Alternate-ladder" (AL) and "slanted column" (SC) motifs occur most frequently; AL is somewhat prevalent in fluoroarene and pyromellitic dianhydride cocrystals, whereas SC occurs preferentially, but not exclusively, with quinones, nitrobenzene, TCNB and TCNQ coformers. Segregation of A and B chemical units in separate columns is very seldom observed, while A center dot center dot center dot B is the energetically dominating pair in a vast majority of the cases. A stable network of stacked A center dot center dot center dot B units seems to be a strict requirement for observing cocrystallization, even more than an overall higher stability of the cocrystal with respect to its coformers. This highlights the central role of kinetic factors in determining the drive to stacking hetero-recognition. Energy dissection using the PIXEL scheme shows that dispersion energies play a dominant but not exclusive role. The interaction between flat organic systems is found to be a viable synthetic approach for cocrystallization, on the same footing as the more popular O-H center dot center dot center dot O, O-H center dot center dot center dot N and N-H center dot center dot center dot O hydrogen bonding. Some practical suggestions for the choice of the best coformers are provided.

The structure of the primary amino acid L-leucine has been determined for the first time by neutron diffraction. This was made possible by the use of modern neutron Laue diffraction to overcome the previously prohibitive effects of crystal size and quality. The packing of the structure into hydrophobic and hydrophilic layers is explained by the intermolecular interaction energies calculated using the PIXEL method. Variable-temperature data collections confirmed the absence of phase transitions between 120 and 300 K in the single-crystal form.

The first example of a NHC-based copper azide complex is reported. Its reactivity was investigated with various reagents affording 8 new complexes. Postprint

International audience; The coupling of the crystallographic refinement technique Hirshfeld atom refinement (HAR) with the recently constructed libraries of extremely localized molecular orbitals (ELMOs) gives rise to the new quantum-crystallographic method HAR-ELMO. This method is significantly faster than HAR but as accurate and precise, especially concerning the free refinement of hydrogen atoms from X-ray diffraction data, so that the first fully quantum-crystallographic refinement of a protein is presented here. However, the promise of HAR-ELMO exceeds large molecules and protein crystallography. In fact, it also renders possible electron-density investigations of heavy elements in small molecules and facilitates the detection and isolation of systematic errors from physical effects.

Cover profile:10.1002/open.201900279. Invited for this month's cover picture are the groups of Professors Rudolf Pietschnig at the University of Kassel, Professor Dietrich Gudat at the University of Stuttgart and Professor Laszlo Nyulaszi at the Budapest University of Technology and Economics. The cover picture shows the thermally induced homolytic cleavage of the central P-P bond in a phosphorus-rich bis-ferrocenophane furnishing P-centered radicals (as evidenced by the computed spin-density highlighted in blue). The central P-6 unit in the title compound is a structural analog of the connecting unit in Hittorf's violet phosphorus, which links the orthogonally arranged tubular entities. A portrait of the German physicist Johann Wilhelm Hittorf is included. Read the full text of their Full Paper at 10.1002/open.201900182.

In this study, we investigate the hydrodynamics of polymer‐induced drag reduction in horizontal turbulent pipe flows. We provide spatiotemporally resolved information of velocity and its gradients obtained with particle image velocimetry (PIV) measurements in solutions of water with dissolved polyethylene oxide (PEO) of three different molecular weights, at various dilute concentrations and with flow Reynolds numbers from 35, 000 to 210, 000. We find that the local magnitudes of important turbulent flow variables correlate with the measured levels of drag reduction irrespective of the flow Reynolds number, polymer weight and concentration. Contour maps illustrate the spatial characteristics of this correlation. A relationship between the drag reduction and the turbulent flow variables is found. The effects of the polymer molecular weight, its concentration and the Reynolds number on the flow are further examined through joint probability distributions of the fluctuations of the streamwise and spanwise velocity components.

The compound [Cu(µ-Pip)(µ-OAc)(MeOH)]2 (1) (Pip = Piperonylate, OAc = acetate, MeOH = methanol) has been obtained in high percentage yield. Its reactivity with pyridine/pyrazole derivative ligands (pyridine (py), 3-phenylpyridine (3-Phpy) and 4-acetylpyridine (4-Acpy)) and 3,5-dimethylpyrazole (3,5-dmpz) leads to four monomeric compounds: [Cu(Pip)2(dPy)2(H2O)] (dPy = py (2), 3-Phpy (3) and 4-Acpy (4a)) and [Cu(Pip)2(3,5-dmpz)2] (5). Furthermore, the reaction of 1 with HPip in MeOH:DMF solvent under reflux conditions yields the homoleptic core paddle-wheel compound [Cu(µ-Pip)2(DMF)]2·2DMF (6). The reaction between 6 and 2-benzylpyridine (2-Bzpy) yields the paddle-wheel core compound [Cu(Pip)2(2-Bzpy)]2 (7). All compounds have been fully characterized by analytical and spectroscopic techniques and their X-ray crystal structures have been determined. In this set of compounds, the carboxylate ligand (Pip) displays different coordination modes (monodentate (2–4), bidentate chelate (5) and bridged (1, 6 and 7)). Moreover, their extended structures are discussed: the crystal packing indicates hydrogen bond propagation, which defines 1D (2–5) or 2D (6 and 7) supramolecular networks., This work was financed by the Spanish National Plan of Research MAT2015-65756-R, CTQ2016-75150-R and 2017SGR1687, 2014SGR149 projects from the Generalitat de Catalunya for its financial support.

Recent demonstrations of inverted thermal activation of charge mobility in polymer field-effect transistors have excited the interest in transport regimes not limited by thermal barriers. However, rationalization of the limiting factors to access such regimes is still lacking. An improved understanding in this area is critical for development of new materials, establishing processing guidelines, and broadening of the range of applications. Here we show that precise processing of a diketopyrrolopyrrole-tetrafluorobenzene-based electron transporting copolymer results in single crystal-like and voltage-independent mobility with vanishing activation energy above 280 K. Key factors are uniaxial chain alignment and thermal annealing at temperatures within the melting endotherm of films. Experimental and computational evidences converge toward a picture of electrons being delocalized within crystalline domains of increased size. Residual energy barriers introduced by disordered regions are bypassed in the direction of molecular alignment by a more efficient interconnection of the ordered domains following the annealing process., Though solution-processed conjugated polymers with inverted temperature activated transport have been reported, the origin of this behaviour is unclear. Here, the authors realize temperature-independent electron transport above 280 K in a donor-acceptor copolymer through microstructural engineering.

International audience; In this review, recent progress in understanding the direct effects of radiation on the structure and stability of collagen, the most abundant protein in the human body, and other proteins is surveyed. Special emphasis is placed on the triple‐helical structure of collagen, as studied by means of collagen mimetic peptides. The emerging patterns are the dose dependence of radiation processes and their abundance, the crucial role of radicals in covalent‐bond formation (crosslinking) or cleavage, and the influence of the radiation energy and nature. Future research should allow fundamental questions, such as charge transfer and fragmentation dynamics triggered by ionization, to be answered, as well as developing applications such as protein‐based biomaterials, notably with properties controlled by irradiation.

The phenomenon of glistenings, often appearing in intraocular lenses (IOLs) of patients after some time from the surgical operation, is potentially able to induce a poor quality of vision and, therefore, frustrate IOL implantation itself. In this paper, we combine optical microscopy with micro-Raman spectroscopy to get a deeper insight on the mechanism ruling, at microscopic scale, glistening formation. In particular, we have analyzed two types of IOLs, characterized by a different internal hydrophobicity but a similar polymer hydration coefficient. Raman imaging of single microvacuoles reveals that water creeps into the polymeric network, which traps water. Finally, applying the Principal Component Analysis (PCA) to Raman data, we provide information on the probable mechanism leading to water trapping in the two kinds of analyzed IOLs. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

While several reviews have been devoted to lower (ethylene and propylene) olefin polymerisation, several other substrates catalysed by vanadium complexes have escaped review. Here, vanadium-based complexes, active as (pre-)catalysts in the polymerisation of higher olefins, ring-opening metathesis polymerisation (ROMP) of alkenes, and ring-opening polymerisation (ROP) of lactones are reviewed. The Ziegler-Natta systems and some oxovanadium and vanadocene single-site pre-catalysts active towards styrene polymerisation are also mentioned. Furthermore, imidovanadium(V) complexes catalysing ROMP with ligands including aryl, aryloxy, and ketimide substituents are thoroughly reviewed and their activities and yields are compared. The ROP of lactides and e-caprolactone is also discussed.

The diazoalkane complexes [Ru(η(5)-C5Me5)(N2CAr1Ar2){P(OR)3}L]BPh4 (1-4) [R = Me, L = P(OMe)3 (1); R = Et, L = P(OEt)3 (2); R = Me, L = PPh3 (3); R = Et, L = PPh3 (4); Ar1 = Ar2 = Ph (a); Ar1 = Ph, Ar2 = p-tolyl (b); Ar1Ar2 = C12H8 (c); Ar1 = Ph, Ar2 = PhC(O) (d)] and [Ru(η(5)-C5Me5){N2C(C12H8)}{PPh(OEt)2}(PPh3)]BPh4 (5c) were prepared by allowing chloro-compounds RuCl(η(5)-C5Me5)[P(OR)3]L to react with the diazoalkane Ar1Ar2CN2 in the presence of NaBPh4. Treatment of complexes 1-4 with H2O afforded 1,2-diazene derivatives [Ru(η(5)-C5Me5)(η(2)-NH═NH){P(OR)3}L]BPh4 (6-9) and ketone Ar1Ar2CO. A reaction path involving nucleophilic attack by H2O on the coordinated diazoalkane is proposed and supported by density functional theory calculations. The complexes were characterized spectroscopically (IR and (1)H, (31)P, (13)C, (15)N NMR) and by X-ray crystal structure determination of [Ru(η(5)-C5Me5)(N2CC12H8){P(OEt)3}2]BPh4 (2c) and [Ru(η(5)-C5Me5)(η(2)-NH═NH){P(OEt)3}2]BPh4 (7).

Semiconductor charge transfer (CT) cocrystals are an emerging class of molecular materials which combines the characteristics of the constituent molecules in order to tune physical properties. Cocrystals can exhibit polymorphism, but different stoichiometries of the donor-acceptor (DA) pair can also give different structures. In addition, the structures of the donor and acceptor as pristine compounds can influence the resulting cocrystal forms. We report a structural study on several CT cocrystals obtained by combining the polyaromatic hydrocarbon perylene with 7,7,8,8-tetracyanoquinodimethane (TCNQ) and its fluorinated derivatives having increasing electronegativity. This is achieved by varying the amount of fluorine substitution on the aromatic ring, with TCNQ-F2 and TCNQ-F4. We find structures with different stoichiometries. Namely, the system perylene:TCNQ-F0 is found with ratios 1:1 and 3:1, while the systems perylene:TCNQ-Fx (x = 2, 4) are found with ratios 1:1 and 3:2. We discuss the structures on the basis of the polymorphism of perylene as pure compound, and show that by a judicious choice of growth temperature the crystal structure can be in principle designed a priori. We also analyze the structural motifs taking into account the degree of charge transfer between the perylene donor and the TCNQ-Fx acceptors and the optical gap determined from infrared (IR) spectroscopy. This family of materials exhibits tunable optical gaps in the near-IR (NIR), promising applications in organic optoelectronics.

Diazoalkane complexes [Fe(eta(5)-C5H5)(N(2)CAr1Ar2)(P-P)]BPh4 (1, 2) [P-P = Ph2PCH2CH2PPh2 (dppe) (1), Ph2PCH2CH2CH2PPh2 (dppp) (2); Ar1 = Ar2 = Ph (a); Ar1 = Ph, Ar2 = p-tolyl (b); Ar1Ar2 = C12H8 (c)] were prepared by allowing chloro compounds FeCl(eta(5)-C5H5)(P-P) to react with diazoalkane in the presence of NaBPh4. Phosphine complex [Fe(eta(5)-C5H5)(dppe)(kappa(1)-PPh2CH2CH2PPh2)]BPh4 (3) was also prepared. Treatment of diazoalkane complexes 1, 2 with acrylonitrile afforded 3H-pyrazole derivatives [Fe(eta(5)- C5H5)-{N=NC(Ar1Ar2)(CH(CN)CH2}(P-P)]BPh4 (4, 5), as well as a small amount of nitrile complex [Fe(eta(5)-C5H5)(kappa(1)-NCC(H)]= CH2)(P-P)]BPh4 (6). The complexes were characterised spectroscopically (IR, NMR) and by X-ray crystal structure determination of [Fe(eta(5)-C5H5){N2C(C12H8)}(dppe)]BPh4 (1c).

Atmospheric chambers have been widely used to study secondary organic aerosol (SOA) properties and formation from various precursors under different controlled environmental conditions and to develop parameterization to represent SOA formation in chemical-transport models (CTM). Chamber experiments are however limited in number, performed under conditions that differ from the atmosphere and can be subject to potential artifacts from chamber walls. Here the Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) modelling tool has been used in a box model under various environmental conditions to (i) explore the sensitivity of SOA formation and properties to changes on physical and chemical conditions and (ii) to develop a Volatility Basis Set type parameterization. The set of parent hydrocarbons includes n-alkanes and 1-alkenes with 10, 14, 18, 22, and 26 carbon atoms, α-pinene, β-pinene and limonene, benzene, toluene, o-xylene, m-xylene and p-xylene. Simulated SOA yields and their dependences on the precursor structure, organic aerosol load, temperature and NOx levels are consistent with the literature. GECKO-A was used to explore the distribution of molar mass, vaporization enthalpy, OH reaction rate and Henry's law coefficient of the millions of secondary organic compounds formed during the oxidation of the different precursors and under various conditions. From these explicit simulations, a VBS-GECKO parameterization designed to be implemented in 3D air quality models has been tuned to represent SOA formation from the 18 precursors using GECKO-A as a reference. Its evaluation shows that VBS-GECKO captures the dynamic of SOA formation for a large range of conditions with a mean relative error on organic aerosol mass temporal evolution lesser than 20 % compared to explicit simulations. The optimization procedure has been automated to facilitate the update of the VBS-GECKO on the basis of the future GECKO-A versions, its extension to other precursors and/or its modification to carry additional information.

Annexins are a family of proteins characterized by their ability to bind anionic membranes in response to Ca2+-activation. They are involved in a multitude of cellular functions including vesiculation and membrane repair. Here, we investigate the effect of nine annexins (ANXA1-ANXA7, ANXA11, ANXA13) on negatively charged double supported membrane patches with free edges. We find that annexin members can be classified according to the membrane morphology they induce and matching a dendrogam of the annexin family based on full amino acid sequences. ANXA1 and ANXA2 induce membrane folding and blebbing initiated from membrane structural defects inside patches while ANXA6 induces membrane folding originating both from defects and from the membrane edges. ANXA4 and ANXA5 induce cooperative roll-up of the membrane starting from free edges, producing large rolls. In contrast, ANXA3 and ANXA13 roll the membrane in a fragmented manner producing multiple thin rolls. In addition to rolling, ANXA7 and ANXA11 are characterized by their ability to form fluid lenses localized between the membrane leaflets. A shared feature necessary for generating these morphologies is the ability to induce membrane curvature on free edged anionic membranes. Consequently, induction of membrane curvature may be a significant property of the annexin protein family that is important for their function.

The mechanochemical technique of ball milling has been applied to the solventless and eco-friendly synthesis of chalcogenides (sulfide and selenide) of a variety of tertiary and aminophosphines. In most of the cases, the products are obtained in almost quantitative yields with high purity by applying a simple workup procedure without using chromatographic techniques or any other purification methods. The scope of this methodology was explored by using a range of phosphines (mono, di and tetra) to synthesize partial as well as mixed chalcogenides. The use of almost equimolar amounts of starting materials and the absence of any byproducts significantly simplifies the product isolation compared with the standard solution state reactions, thus providing a highly atom economic (100%) method with an ideal E-factor (E = 0). The solid-state reactions were monitored by P-31{H-1} NMR spectroscopy. The structures of some of the products are also confirmed by single-crystal X-ray analyses. Although most of the reactions were carried out on ca. 100-mg scale, the scaling up of the reaction did not affect the course of the reaction.

A (2+2) Dipodal condensation of bis{6-formyl-(2,3,4-trimethoxy)phenyl}mercury (14) with various 1,2-disubstitued diamines e.g., ethylenediamine, trans-1,2-diaminocyclohexane and o-phenylenediamine led to the formation of 22-membered mercuraazametallamacrocycles, [Hg-{1-C6H-2,3,4-(OCH3)(3)-6-(CHN)}(2)-CH2-CH2](2) (15), [Hg-{1-C6H-2,3,4-(OCH3)(3)-6-(CHN)}(2)-C6H10](2) (16) and [Hg-{1-C6H-2,3,4-(OCH3)(3)-6-(CHN)}(2)-C6H4](2) (17) respectively. The acceptor abilities and reactivities of the macrocycles are compared with the corresponding 22-membered mercuraazametallamacrocycles obtained from the condensation of bis(formylphenyl)mercury (12) with the diamines. Also attempts have been made to prepare macrocycles with functionalized aryldiamines. Orange colored Cu-I complexes, 24 ([15 center dot Cu]ClO4) and 26 ([16 center dot Cu]ClO4), were obtained upon the treatment of [Cu(CH3CN)(4)ClO4] with macrocycles 15 and 16, respectively. Similarly, brown colored Ag-I complexes, 25 ([15 center dot Ag]ClO4), and 27 ([16 center dot Ag]ClO4) were isolated by reacting macrocycles 15 and 16 with AgClO4. The reaction of macrocycle 15 with equimolar Pt(COD)Cl-2 afforded cyclometalated platinum(II) complex, Pt-{1-C6H-2,3,4-(OCH3)(3)-6-(CHN-CH2)}(2) (28). Bis(2-amino-5-methylphenyl)mercury (23), shows a very strong intermolecular HgHg interaction. Density functional theory calculations and atoms in molecules analysis revealed the presence of metallophilic d(10)center dot center dot center dot d(10) interactions as well as d(10)center dot center dot center dot d(8) interactions in the synthesized compounds.