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The first synthesis of 2,4-bis(3,4-dimethoxyphenyl)-1,3-dithia-2,4-diphosphetane 2,4-disulfide (SAV-A1 reagent) was achieved. Seven oxo-alkyl esters (HLn) were synthesized thereof. Ni(II) complexes ([Ni(Ln)(2)]) of these ligands were prepared in ethanol. The structures were identified by spectral studies. Ni(II) complexes were unambiguously determined by X-ray crystallography. In addition, the ligands and their Ni(II) complexes were tested on two different human cancer cell lines, including liver and colon. Moreover, density functional theory (DFT) calculations of the Ni(II) complexes were performed, and the molecular docking studies of these compounds with liver cancer protein, PDB ID: 3WZE and colon cancer antigen proteins, ID 2HQ6 were presented to investigate and predict potential interactions.

Correction: 10.1021/acs.joc.1c02513. The tear film lipid layer (TFLL) that covers the ocular surface contains several unique lipid classes, including O-acyl-omega-hydroxy fatty acids, type I-St diesters, and type II diesters. While the TFLL represents a unique biological barrier that plays a central role in stabilizing the entire tear film, little is known about the properties and roles of individual lipid species. This is because their isolation from tear samples in sufficient quantities is a tedious task. To provide access to these species in their pure form, and to shed light on their properties, we here report a general strategy for the synthesis and structural characterization of these lipid classes. In addition, we study the organization and behavior of the lipids at the air-tear interface. Through these studies, new insights on the relationship between structural features, such as number of double bonds and the chain length, and film properties, such as spreading and evaporation resistance, were uncovered.

Nanopore heterogeneity has a significant effect on adsorption, desorption, and diffusion processes of coalbed methane. The adsorption pore size distribution heterogeneity was calculated by combining N2 with CO2 adsorption data, and factors affecting multifractal and single-fractal dimensions were studied. The results indicate that pore size distribution of micropores (with pore diameters smaller than 2 nm) and meso-macro-pores (with pore diameters between 2 and 100 nm) in coal samples exhibit typical multifractal behavior. The overall heterogeneity of micropores in high-rank coal samples is higher than that in the middle-rank coal samples. The low-probability measure areas control the overall heterogeneity of pores with diameters of 0.40-1.50 nm. The high-probability measure area heterogeneity and spectral width ratio have a higher linear correlation with coal rank and pore structure parameters than those of low-probability measure areas. Heterogeneity of high-probability measure areas and overall pore size distribution are controlled by pores with diameters of 0.72-0.94 nm. Multifractal parameters of meso-macro-pores have no clear relationship with coal rank. The pore volume of 2-10 nm diameter shows a good linear correlation with heterogeneity of low-probability measure areas, and pores of this diameter range are the key interval that affected pore size distribution heterogeneity. The single-fractal dimension obtained using the Frenkel-Halsey-Hill (FHH) model shows a positive linear correlation with heterogeneity of the low-probability measure areas. It indicates that this parameter can effectively characterize the pore size distribution heterogeneity of low-probability measure areas in meso-macro-pores. ispartof: ACS OMEGA vol:5 issue:31 pages:19385-19401 ispartof: location:United States status: published

Aluminium oxide and gallium oxide nanorods were identified as highly efficient heterogeneous catalysts for the selective oxidation of aromatic amines to azoxy compounds using hydrogen peroxide as environmentally friendly oxidant. This is the first report of the selective oxidation of aromatic amines to their azoxy derivatives without using transition metal catalysts. Among the tested transition-metal-free oxides, gallium oxide nanorods with small dimensions (9-52 nm length and 3-5 nm width) and fully accessible, high surface area (225 m(2) g(-1)) displayed the best catalytic performance in terms of substrate versatility, activity and azoxybenzene selectivity. Furthermore, the catalyst loading, hydrogen peroxide type (aqueous or anhydrous), and the amount of solvent were tuned to optimise the catalytic performance, which allowed reaching almost full selectivity (98 %) towards azoxybenzene at high aniline conversion (94 %). Reusability tests showed that the gallium oxide nanorod catalyst can be recycled in consecutive runs with complete retention of the original activity and selectivity.

Although the vast majority of women encounters at least one vaginal infection during their life, the amount of microbiome-related research performed in this area lags behind compared to alternative niches such as the intestinal tract. As a result, effective means of diagnosis and treatment, especially of recurrent infections, are limited. The role of the metabolome in vaginal health is largely elusive. It has been shown that lactate produced by the numerous lactobacilli present promotes health by limiting the chance of infection. Short chain fatty acids (SCFA) have been mainly linked to dysbiosis, although the causality of this relationship is still under debate. In this review, we aim to bring together information on the role of the vaginal metabolome and microbiome in infections caused by Candida. Vulvovaginal candidiasis affects near to 70% of all women at least once in their life with a significant proportion of women suffering from the recurrent variant. We assess the role of fatty acid metabolites, mainly SCFA and lactate, in onset of infection and virulence of the fungal pathogen. In addition, we pinpoint where lack of research limits our understanding of the molecular processes involved and restricts the possibility of developing novel treatment strategies. ispartof: FRONTIERS IN MICROBIOLOGY vol:12 ispartof: location:Switzerland status: published

Resolution in proton solid state magic angle sample spinning (MAS) NMR is limited by the intrinsically imperfect nature of coherent averaging induced by either MAS or multiple pulse sequence methods. Here, we suggest that instead of optimizing and perfecting a coherent averaging scheme, we could approach the problem by parametrically mapping the error terms due to imperfect averaging in a k-space representation, in such a way that they can be removed in a multidimensional correlation leaving only the desired pure isotropic signal. We illustrate the approach here by determining pure isotropic H-1 spectra from a series of MAS spectra acquired at different spinning rates. For six different organic solids, the approach is shown to produce pure isotropic H-1 spectra that are significantly narrower than the MAS spectrum acquired at the fastest possible rate, with linewidths down to as little as 48 Hz. On average, we observe a 7-fold increase in resolution, and up to a factor of 20, as compared with spectra acquired at 100 kHz MAS. The approach is directly applicable to a range of solids, and we anticipate that the same underlying principle for removing errors introduced here can be applied to other problems in NMR spectroscopy.

BACKGROUND: Cholesterol Efflux Capacity (CEC) is considered to be a key atheroprotective property of high-density lipoproteins (HDL). However, the role of HDL-CEC in atherosclerosis and cardiovascular (CV) risk is still controversial, and data in individuals with diabetes are limited.OBJECTIVE: In this study, we have investigated the relationship of CEC and other HDL characteristics with clinical and subclinical atherosclerosis in subjects with elevated cardiovascular diseases (CVD) risk and Type 2 Diabetes Mellitus (T2DM).METHODS: Using multiple linear regression analyses, we determined the relationship of HDL-CEC with carotid intima-media thickness (cIMT, Z-Score), an endothelial dysfunction (EnD) Score (Z-Score), prevalent CVD (n = 150 cases) and history of CV events (CVE, n = 85 cases) in an observational cohort (CODAM, n = 574, 59.6 ± 0.3 yr, 61.3% men, 24.4% T2DM). Stratified analyses were performed to determine if the associations differed between individuals with normal glucose metabolism (NGM) and those with disturbed glucose metabolism.RESULTS: HDL-CEC was not associated with either marker of atherosclerosis (cIMT, EnD Score) nor with CVD or CVE. In contrast, other HDL characteristics that is, HDL-Cholesterol (HDL-C, Z-Score), apolipoprotein A-I (apoA-I, Z-Score), HDL size (Z-Score) and HDL particle number (HDL-P, Z-Score) were inversely and significantly associated with the EnD Score (s -0.226 to -0.097, P < .05) and CVE (ORs 0.61 to 0.68, P < .05). In stratified analyses, HDL size and HDL-P were significantly associated with the EnD Score in individuals with NGM (Pinteraction .039 and .005, respectively), but not in those with (pre)diabetes. HDL-C and apoA-I were inversely associated with prevalent CVD in individuals with (pre)diabetes (Pinteraction = .074 and .034, respectively), but not in those with NGM.CONCLUSION: HDL-CEC is not associated with clinical or subclinical atherosclerosis, neither in the whole population nor in individuals with (pre)diabetes, while other HDL characteristics show atheroprotective associations. The atheroprotective associations of HDL-size and HDL-P are lost in (pre)diabetes, while higher concentrations of HDL-C and apoA-I are associated with a lower prevalence of CVD in (pre)diabetes.

Shape memory polymers (SMPs) are an exciting class of stimuli-responsive smart materials that demonstrate reactive and reversible changes in mechanical property, usually by switching between different states due to external stimuli. We report on the development of a polyurethane-based SMP foam for effective pressure redistribution that demonstrates controllable changes in dynamic pressure redistribution capability at a low transition temperature (∼24 °C)-ideally suited to matching modulations in body contact pressure for dynamic pressure relief (e.g., for alleviation or pressure ulcer effects). The resultant SMP material has been extensively characterized by a series of tests including stress-strain testing, compression testing, dynamic mechanical analysis, optical microscopy, UV-visible absorbance spectroscopy, variable-temperature areal pressure distribution, Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, differential scanning calorimetry, dynamic thermogravimetric analysis, and 1H nuclear magnetic resonance spectroscopy. The foam system exhibits high responsivity when tested for plantar pressure modulation with significant potential in pressure ulcers treatment. Efficient pressure redistribution (∼80% reduction in interface pressure), high stress response (∼30% applied stress is stored in fixity and released on recovery), and excellent deformation recovery (∼100%) are demonstrated in addition to significant cycling ability without performance loss. By providing highly effective pressure redistribution and modulation when in contact with the body's surface, this SMP foam offers novel mechanisms for alleviating the risk of pressure ulcers. ispartof: ACS OMEGA vol:4 issue:13 pages:15348-15358 ispartof: location:United States status: published

We demonstrated nanoscale MRI of metabolism in single isolated mitochondria and within living cells using NV centers in diamond., Free radicals play a vital role in all kinds of biological processes including immune responses. However, free radicals have short lifetimes and are highly reactive, making them difficult to measure using current methods. Here, we demonstrate that relaxometry measurement, or T1, inherited from the field of diamond magnetometry can be used to detect free radicals in living cells with subcellular resolution. This quantum sensing technique is based on defects in diamond, which convert a magnetic signal into an optical signal, allowing nanoscale magnetic resonance measurements. We functionalized fluorescent nanodiamonds (FNDs) to target single mitochondria within macrophage cells to detect the metabolic activity. In addition, we performed measurements on single isolated mitochondria. We were able to detect free radicals generated by individual mitochondria in either living cells or isolated mitochondria after stimulation or inhibition.

Catalyst deactivation due to coking is a major challenge in the catalytic fast pyrolysis (CFP) of biomass. Here, a multitechnique investigation of a technical Al2O3-bound ZSM-5-based extrudate catalyst, used for the CFP of pine wood and cellulose (at a reactor temperature of 500 °C), provided insight into the effects of extrusion, the catalytic pyrolysis process, and catalyst regeneration on the catalyst structure. As a result of a reduction in acidity and surface area due to the coking catalyst, the activity dropped drastically with increasing time-on-stream (TOS), as evidenced by a decrease in aromatics yield. Strikingly, confocal fluorescence microscopy at the single-particle level revealed that vapor components derived from whole biomass or just the cellulose component coke differently. While pine-wood-derived species mainly blocked the external area of the catalyst particle, larger carbon deposits were formed inside the catalyst's micropores with cellulose-derived species. Pyridine FT-IR and solid-state NMR spectroscopy demonstrated irreversible changes after regeneration, likely due to partial dealumination. Taken together with

A solvometallurgical process for the separation of indium(iii) and zinc(ii) from ethylene glycol solutions using the ionic liquid extractants Cyphos IL 101 and Aliquat 336 in an aromatic diluent has been investigated. The speciation of indium(iii) in the two immiscible organic phases was investigated by Raman spectroscopy, infrared spectroscopy, EXAFS and 115In NMR spectroscopy. At low LiCl concentrations in ethylene glycol, the bridging (InCl3)2(EG)3 or mononuclear (InCl3)(EG)2 complex is proposed. At higher lithium chloride concentrations, the first coordination sphere changes to two oxygen atoms from one bidentate ethylene glycol ligand and four chloride anions ([In(EG)Cl4]-). In the less polar phase, indium(iii) is present as a tetrahedral [InCl4]- complex independent of the LiCl concentration. After the number of theoretical stages had been determined using a McCabe-Thiele diagram for extraction by Cyphos IL 101, the extraction and scrubbing processes were performed in lab-scale mixer-settlers to test the feasibility of working in continuous mode. Indium(iii) was extracted quantitatively in four stages, with 19% co-extraction of zinc(ii). The co-extracted zinc(ii) was scrubbed selectively in six stages using an indium(iii) scrub solution. Indium(iii) was recovered from the loaded less polar organic phase as indium(iii) hydroxide (98.5%) by precipitation stripping with an aqueous NaOH solution. ispartof: RSC ADVANCES vol:10 issue:41 pages:24595-24612 ispartof: location:England status: published

The joint consensus panel of the European Atherosclerosis Society (EAS) and the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) recently addressed present and future challenges in the laboratory diagnostics of atherogenic lipoproteins. Total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDLC), LDL cholesterol (LDLC), and calculated non-HDLC (=total – HDLC) constitute the primary lipid panel for estimating risk of atherosclerotic cardiovascular disease (ASCVD) and can be measured in the nonfasting state. LDLC is the primary target of lipid-lowering therapies. For on-treatment follow-up, LDLC shall be measured or calculated by the same method to attenuate errors in treatment decisions due to marked between-method variations. Lipoprotein(a) [Lp(a)]-cholesterol is part of measured or calculated LDLC and should be estimated at least once in all patients at risk of ASCVD, especially in those whose LDLC declines poorly upon statin treatment. Residual risk of ASCVD even under optimal LDL-lowering treatment should be also assessed by non-HDLC or apolipoprotein B (apoB), especially in patients with mild-to-moderate hypertriglyceridemia (2–10 mmol/L). Non-HDLC includes the assessment of remnant lipoprotein cholesterol and shall be reported in all standard lipid panels. Additional apoB measurement can detect elevated LDL particle (LDLP) numbers often unidentified on the basis of LDLC alone. Reference intervals of lipids, lipoproteins, and apolipoproteins are reported for European men and women aged 20–100 years. However, laboratories shall flag abnormal lipid values with reference to therapeutic decision thresholds.

Two N-heterocyclic phosphines with exocyclic SCN substituents were synthesised via metathesis of chlorophosphine precursors with KSCN and fully characterised. The crystallographic studies reveal that the products exhibit pronounced structural differences. The thiocyanato unit binds in one case via the nitrogen atom to yield a molecular structure with a slightly elongated P-N single bond and, in the other case, via the sulfur atom to form a structure that is best described as an ion pair and forms a one-dimensional coordination polymer in the crystal. DFT calculations suggest that the P-N and P center dot center dot center dot S interactions can be described as covalent and dative bonds, respectively, and that the structural differences correlate with the different cation stabilities of the individual phosphenium cation fragments.

The Gd(iii)-complexes of three novel HP-DO3A-like ligands have been investigated to assess the relationship between relaxometry and intramolecular catalysis of the proton exchange. The structures of these ligands differ from the parent HP-DO3A because the methyl group of the hydroxy-propyl arm has been replaced by -Ph-OH, -Ph-NH2 and -Ph-COOH, respectively. The phenol, amine and carboxylate functionalities display an intramolecular H-bonding with the coordinated hydroxyl moiety that affects either the pK values of the involved functionalities and the rate of the proton exchange process.

We report on the C-60, Na, and Li dynamics in NaxLi6xC60 fullerides (x = 0, 1, 5, and 6) in the temperature range 80-550 K by using C-13, Na-23, and Li-7 solid state NMR. The results show that the C-60 reorientation dynamics is hindered at room temperature for the Li-enriched fullerides, but it is active for the Na rich ones with a rate of the order of few kilohertz. Na-23 and Li-7 NMR measurements show the presence of two dominant thermally activated dynamics that can be associated with Li/Na ionic motions within the octahedral sites (intrasite motion) and between the octahedral and tetrahedral sites (intersite motion). The substitution of one Na or one Li ion in the end members Li6C60 and Na6C60, respectively, yields to an increase of the hopping rate of the intersite motion, which is necessary for the ionic diffusion in possible fulleride-based ionic conductors.

The effect of the enrichment of sunflower oil with gamma-tocopherol on the evolution of its oxidation is the subject of this study. Sunflower oil and samples of this oil enriched with different gamma-tocopherol concentrations are submitted to accelerated storage conditions and their evolution, until total polymerization is monitored by H-1 NMR spectroscopy. The concentrations of linoleic acyl groups, of primary and of a great number of secondary oxidation compounds are determined throughout the process. These concentrations, and the times at which the main changes in them occur are analyzed to elucidate if they are valid markers of the global effect of gamma-tocopherol enrichment. It is proved for the first time that certain comparisons between concentrations of some of the compounds formed in oxidation can lead to erroneous conclusions about the effect of this enrichment. It is shown that, during a first short period of time under accelerated storage conditions, the higher the concentration of gamma-tocopherol the faster the degradation of linoleic acyl groups and the higher the concentration of hydroperoxides; after this first period this relationship is more complex. Generally, the higher the gamma-tocopherol concentration the slower the degradation of the oil, except in the first period.Practical Applications: This study provides very valuable information about the effect caused by enrichment with gamma-tocopherol on sunflower oil oxidative stability and oxidation across a very broad range of concentrations. In addition, the amount of information obtained can be of great importance from several points of view because the oxidation process has been monitored globally. This may be of interest not only to researchers involved in the analysis of oxidation mechanisms but also to those in the field of technology and edible oil legislation, and even to those worried about edible oil safety and its effect on nutrition and health. Another important feature of this study, from the practical point of view, is the methodology used because it does not involve the chemical modification of the sample and the same H-1 NMR spectrum is able to provide information about all the above-mentioned aspects. Sunflower oil enriched with different levels of gamma-tocopherol. Concentrations of primary and secondary oxidation compounds after 4 and 9 days, respectively, under accelerated storage conditions. This work has been supported by the Spanish Ministry of Economy and Competitiveness (MINECO AGL 2015-65450-R), the Basque Government (EJ-GV, IT-916-16), and the Agriculture Department of the Basque Government (PA19/02).

To valorize oleaginous Schizochytrium sp. biomass, a novel sequential process was addressed and developed to simultaneously produce high value DHA-enriched glycerides and low value bulky biodiesels. In this process, Schizochytrium sp. biomass was first treated by alkaline protease; then the resulting biomass was directly subjected to enzymatic ethanolysis catalyzed by liquid enzymes from C. antarctica (CALA), T. lanuginosus (TL), R. miehei (RM) and A. oryzae (PLA). For all four liquid lipases, the alkaline protease treatment on Schizochytrium sp. biomass significantly enhanced total lipid recovery, biodiesel yield and yield of DHA-enriched glycerides. Under optimized conditions, CALA and TL achieved the highest biodiesel yields 76.28–76.66 wt% based on microalgae TFAs while PLA had the lowest (55.25 wt%). Moreover, CALA attained the highest DHA (77.93 wt%) and LC PUFAs (93.08 wt%) contents in glyceride fraction, suggesting a superior performance to concentrate DHA and LC PUFAs in glycerides. 13 C NMR analysis illustrated that non-regiospecificity and unfavorability towards LC PUFAs of CALA made it possible to transesterify saturated fatty acids located in all 3 positions of microalgal oil; thus LC PUFAs were highly enriched in glycerides. Overall, the sequential process using enzymes and ethanol as green media was successfully established for the co-production of high-value microalgal bioproducts rich in LC PUFAs and sustainable biodiesels in a comprehensive manner.

The bimetallic borohydride-chloride LiLa(BH4)3Cl, the lithium amide-iodide Li3(NH2)2I, and the lithium monocarba-closo-decaborate Li-1-CB9H10 represent complex hydrides showing superionic conductivity at room temperature or slightly above it. To study the Li-ion diffusivity that is closely related to the ionic conductivity, we have measured the diffusion coefficients of Li+ cations in these compounds using the pulsed-field-gradient (PFG) spin-echo technique over the temperature range of 298–403 K. The experiments have revealed fast Li+ diffusivities in all these complex hydrides: at 400 K, the measured diffusion coefficients exceed 10−7 cm2/s for LiLa(BH4)3Cl, 5 × 10−8 cm2/s for Li3(NH2)2I, and 10−6 cm2/s for Li-1-CB9H10. For LiLa(BH4)3Cl and Li3(NH2)2I, the diffusion coefficients are found to follow the Arrhenius behavior over the entire temperature ranges studied with the activation energies of 268(6) meV and 224(6) meV, respectively. For Li-1-CB9H10, the Arrhenius behavior with the activation energy of 265(6) meV is observed in the disordered high-temperature polymorph (360–403 K), whereas below 360 K the measured diffusivity drops significantly due to the transition to the ordered phase. Comparison of the measured Li+ diffusion coefficients with the ionic conductivity results and the data on the cation and anion jump rates provides new insights into the unusual dynamical properties of these superionic materials.

Two PDMS-SiO2-TiO2-Cao porous hybrid materials were prepared using the same base composition, precursors, and solvents, but following two different sol-gel procedures, based on the authors' previous works where for the first time, in this hybrid system, calcium acetate was used as calcium source. The two different procedures resulted in monolithic materials with different structures, microstructures, and surface wettability. Even though both are highly hydrophobic (contact angles of 127.2 degrees and 150.6 degrees), and present different filling regimes due to different surface topographies, they have demonstrated to be-cytocompatible when tested with human osteoblastic cells, against the accepted idea that high-hydrophobic surfaces are not suitable to cell adhesion and proliferation. At the nanoscale, the existence of hydrophilic silica domains containing calcium, where water molecules are physisorbed, is assumed to support this capability, as discussed. (C) 2016 Elsevier B.V. All rights reserved.

High-resolution Al-27 magic-angle spinning (MAS) NMR spectroscopy of dehydrated M-forms (M = Li, Na, and K) of chabazite in tandem with density functional theory calculations are employed to study the quadrupolar interaction of Al-27 nuclei in dehydrated zeolites and to understand the corresponding high-resolution Al-27 MAS NMR spectra. We show that the broadening of the Al-27 NMR signal in dehydrated zeolites occurs predominantly because of the deformation of the local structure of AlO4- tetrahedra caused by the binding of M+ to the zeolite framework. This deformation increases with the decreasing diameter of the cations from K+ to Li+. The influence of water in hydrated zeolites is limited only to prevent a strong coordination of the M+ cation to O atoms of the AlO4- tetrahedron, but there is no "averaging" effect concerning the local electrostatic field due to molecular motion of water molecules. Our results show that the Al-27 NMR parameters in dehydrated zeolites can be calculated accurately enough to allow the description of the local structure of AlO4- tetrahedra in dehydrated zeolites and to infer the local structure of the sites accommodating the extraframework M+ cations. 27Al MAS NMR spektroskopie vysokého rozlišení dehydratovaných kationtových (Li+, Na+, K+) forem chabazitu doprovázená DFT výpočty je použita ke studiu kvadrupolární interakce jader 27Al a k porozumění odpovídajících vysoce rozlišených 27Al MAS NMR spekter. Předvádíme zde, že příčinou rozšíření 27Al MAS NMR spekter v dehydratovaných zeolitech je zejména deformace lokální struktury čtyřstěnu AlO4- způsobená navázáním kationtu na strukturu zeolitu. Tato deformace se zvětšuje se zmenšujícím se poloměrem kationtu. Molekuly vody v hydratovaných zeolitech zabraňují navázání kationtu a deformaci čtyřstěnu AlO4-. Naše výsledky ukazují, že 27Al MAS NMR parametry dehydratovaných zeolitů mohou být vypočteny s dostatečnou přesností umožnující popis lokální struktury čtyřstěnu AlO4- a odvození lokální struktury pozic mimo-mřížkových kationtů.

The computational study of conformational transitions in nucleic acids still faces many challenges. For example, in the case of single stranded RNA tetranucleotides, agreement between simulations and experiments is not satisfactory due to inaccuracies in the force fields commonly used in molecular dynamics simulations. We here use experimental data collected from high-resolution X-ray structures to attempt an improvement of the latest version of the AMBER force field. A modified metadynamics algorithm is used to calculate correcting potentials designed to enforce experimental distributions of backbone torsion angles. Replica-exchange simulations of tetranucleotides including these correcting potentials show significantly better agreement with independent solution experiments for the oligonucleotides containing pyrimidine bases. Although the proposed corrections do not seem to be portable to generic RNA systems, the simulations revealed the importance of the alpha and beta backbone angles on the modulation of the RNA conformational ensemble. The correction protocol presented here suggests a systematic procedure for force-field refinement.

We report an extensive 600 MHz NMR trial of a quantitative lipoprotein and small molecule measurements in human blood serum and plasma. Five centers with eleven 600 MHz NMR spectrometers were used to analyze 98 samples including: 20 QCs, 37 commercially sourced, paired serum and plasma samples and 2 National Institute of Science and Technology, NIST, reference material 1951c replicates. Samples were analyzed using rigorous protocols for sample preparation and experimental acquisition. A commercial lipoprotein subclass analysis was used to quantify 105 lipoprotein subclasses and 24 low molecular weight metabolites from the nuclear magnetic resonance, NMR, spectra. For all spectrometers, the instrument specific variance in measuring internal quality controls, QCs, was lower than the percentage described by the National Cholesterol Education Program, NCEP, criteria for lipid testing (triglycerides

WOS:000442065200016; Mn2+ often serves as a paramagnetic substitute to Mg2+, providing means for exploring the close environment of Mg2+ in many biological systems where it serves as an essential co-factor. This applies to proteins with ATPase activity, where the ATP hydrolysis requires the binding of Mg2+-ATP to the ATPase active site. In this context, it is important to distinguish between the Mn2+ coordination mode with free ATP in solution as compared to the protein bound case. In this work, we explore the Mn2+ complexes with ATP, the non-hydrolysable ATP analog, AMPPNP, and ADP free in solution. Using W-band P-31 electron-nuclear double resonance (ENDOR) we obtained information about the coordination to the phosphates, whereas from electron-electron double resonance (ELDOR) - detected NMR (EDNMR) we determined the coordination to an adenosine nitrogen. The coordination to these ligands has been reported earlier, but whether the nitrogen and phosphate coordination is within the same nucleotide molecules or different ones is still under debate. By applying the correlation technique, THYCOS (triple hyperfine correlation spectroscopy), and measuring N-15-P-31 correlations we establish that in Mn-ATP in solution both phosphates and a nitrogen are coordinated to the Mn2+ ion. We also carried out DFT calculations to substantiate this finding. In addition, we expanded the understanding of the THYCOS experiment by comparing it to 2D-EDNMR for Mn-55-P-31 correlation experiments and through simulations of THYCOS and 2D-EDNMR spectra with N-15-P-31 correlations. (C) 2018 Elsevier Inc. All rights reserved.

The successful application of solid-state NMR spectroscopy for structural study of biological macromolecules requires high spectral resolution. In presence of abundant H 1 spins, the resolution of the prevailing C 13 or N 15 chemical shift encoding experiments critically depends on the availability of efficient and robust heteronuclear decoupling methods in addition to the use of high-field instrumentation and fast sample spinning. Robustness of the decoupling method towards alterations in amplitude/offset of radio frequency fields due to varying sample states is important to ensure recording of spectra with high resolution over long sampling periods for insensitive samples. Here, we present a phase-alternated refocused continuous-wave decoupling method offering better resolution, easier setup, and higher robustness than previous methods. Improved decoupling is in part ascribed to more efficient cancellation of the residual heteronuclear, H 1 – C 13 , dipolar coupling interactions which are induced by homonuclear, H 1 – H 1 , dipolar coupling interactions.

The new compounds Rbpy)(2)Os-II(mu-L-1(2-))Os-II(bpy)(2)](ClO4)(2) ([1]-(ClO4)(2)) and [(pap)(2)Os-II(mu-L,2)Os-II(pap)(2)] (ClO4)(2) ([2](ClO4)(2)) (H(2)L1 = 1,4dihydroxy-9,10-anthraquinone, bpy = 2,2/-bipyridine, and pap = 2-phenylazopyridine) and Rbpy)(2)Os-II(mu-L-2(center dot-))Os-II(bpy)(2)] (ClO4)(3) ([3] (ClO4)(3)) and Rpap)(2)Os-II(itL22-)Os-11(pap)(2)] (ClO4)(2) ([4] (ClO4)(2)) (H2L2 = 1,4-diamino-9,10-anthraquinone) have been analytically identified as the meso and rac diastereoisomers, respectively. The paramagnetic [3] (ClO4)(3) was also characterized by crystal structure determination. In CD3CN solution, [3] (ClO4)(3) displays rather narrow but widely split (13 > 5> 8 ppm) resonances in the 11-1 NMR spectrum, yet no EPR signal was observed down to 120 K Cyclic voltammetry and differential pulse voltammetry reveal several accessible redox states on oxidation and reduction, showing that the replacement of 1,4-oxido by imido donors causes cathodic shifts and that the substitution of bpy by the stronger 2T-accept ng pap ligands leads to a strong increase of redox potentials. Accordingly, system 3" with the lowest (2+13+) potential was synthetically obtained in the mono-oxidized (3+) form. The (3+) intermediates display small comproportionation constants lc of about 103 and long-wavelength near-infrared absorptions; an EPR signal with appreciable g splitting (1.84, 1.96, and 2.03) was only observed for 43+, which exhibits the smallest spin density on the osmium centers. An oxidation state formulation [Os-III(y1.73-)Os-III]3+ with some [Osii(mu-L2-)Os3+ contribution was found to best describe the electronic structures. UV-vis NIR absorption spectra were recorded for all accessible states by OTTLE spectroelectrochemistry and assigned on the basis of TDDFT calculations. These results and additional EPR measurements suggest rather variegated oxidation state situations, e.g., the pap ligands competing with the bridge L for electrons, while the oxidation produces mixed spin systems with variable metal/ ligand contributions.

In contrast to the extensively investigated beta-turn conformation in peptides and proteins, single and multiple gamma-turns have been much less commonly studied. Single and non-contiguous multiple gamma-turns have been relatively often authenticated in small cyclic peptides, but these important peptide main-chain reversal motifs have not been examined carefully either in linear peptides or in globular proteins. This Perspective article summarizes literature data on this aspect of peptide stereochemistry, expanding the discussion also to the rarely found, contiguous multiple gamma-turns which generate incipient or fully-developed 2.2(7)-(gamma-)helices. Unpublished results of recent research activities on this topic ongoing in our laboratories are also briefly outlined.

Specific synthetic routes are presented in schemes to illustrate the chemistry, and the analogs are presented in a table format to give an accessible overview of the structures. Several patents have been published regarding the properties of griseofulvin and its derivatives including synthesis, formulation, and their medicinal and agricultural applications. The antifungal mode-of-action of griseofulvin has been the subject of considerable research efforts and some debate over the years, a discussion that is still ongoing. Griseofulvin was one of the first antifungal natural products found in filamentous fungi. During the years, this polyketide has been found to be produced by several Ascomycetes including both closely and distantly related species.

Polyglutamine expansion in the huntingtin protein is the primary genetic cause of Huntington's disease (HD). Fragments coinciding with mutant huntingtin exon1 aggregate in vivo and induce HD-like pathology in mouse models. The resulting aggregates can have different structures that affect their biochemical behaviour and cytotoxic activity. Here we report our studies of the structure and functional characteristics of multiple mutant htt exon1 fibrils by complementary techniques, including infrared and solid-state NMR spectroscopies. Magic-angle-spinning NMR reveals that fibrillar exon1 has a partly mobile α-helix in its aggregation-accelerating N terminus, and semi-rigid polyproline II helices in the proline-rich flanking domain (PRD). The polyglutamine-proximal portions of these domains are immobilized and clustered, limiting access to aggregation-modulating antibodies. The polymorphic fibrils differ in their flanking domains rather than the polyglutamine amyloid structure. They are effective at seeding polyglutamine aggregation and exhibit cytotoxic effects when applied to neuronal cells., Huntington's disease is caused by a polyglutamine stretch expansion in the first exon of huntingtin. Here, the authors use infrared spectroscopy and solid-state NMR and show that polymorphic huntingtin exon1 fibres differ in their flanking regions but not their core polyglutamine amyloid structures.

Lithium amideborohydrides Li[BH4](1x)[NH2](x) possess liquid-like Li superionic conductivity at nearly ambient temperature. The fast Li+ diffusion facilitated by the localized motions of the anions is proposed to occur through a network of vacant tetrahedral sites, acting as conduction channels. To study the reorientational dynamics of the anions, we have performed quasielastic neutron scattering experiments on samples with different compositions (x = 2/3, 0.722, 0.737, 3/4) over a broad temperature and time range. To unambiguously disentangle the contributions of the two species, [BH4](-) and [NH2](-), we took advantage of deuterium labeling and could clearly demonstrate that the quasielastic broadening is mainly determined by the [BH4](-) reorientations. With the help of a newly developed model, supported by ab initio molecular dynamics calculations, we have identified three relaxation components, which account for generally anisotropic C-3-rotations of the [BH4](-) tetrahedra including jumps by a small angle from the equilibrium position.

Nowadays different experimental techniques, such as single molecule or relaxation experiments, can provide dynamic properties of biomolecular systems, but the amount of detail obtainable with these methods is often limited in terms of time or spatial resolution. Here we use state-of-the-art computational techniques, namely atomistic molecular dynamics and Markov state models, to provide insight into the rapid dynamics of short RNA oligonucleotides, in order to elucidate the kinetics of stacking interactions. Analysis of multiple microsecond-long simulations indicates that the main relaxation modes of such molecules can consist of transitions between alternative folded states, rather than between random coils and native structures. After properly removing structures that are artificially stabilized by known inaccuracies of the current RNA AMBER force field, the kinetic properties predicted are consistent with the timescales of previously reported relaxation experiments., Accepted for publication on J. Chem. Theory Comput

The reaction of 2,2'-bipyridine-3,3'-diol (H2L) and cis-Os-II(bpy)(2)Cl-2 (bpy = 2,2'-bipyridine) results in isomeric forms of [Os-II(bpy)(2)(HL-)]ClO4, [1]ClO4 and [2]ClO4, because of the varying binding modes of partially deprotonated HL-. The identities of isomeric [1]ClO4 and [2]ClO4 have been authenticated by their single crystal X-ray structures. The ambidentate HL- in [2]ClO4 develops the usual N,N bonded five-membered chelate with a strong O-H center dot center dot center dot O hydrogen bonded situation (O-H center dot center dot center dot O angle: 160.78 degrees) at its back face. The isomer [1]ClO4 however represents the monoanionic O-,N coordinating mode of HL-, leading to a six-membered chelate with the moderately strong O-H center dot center dot center dot N hydrogen bonding interaction (O-H center dot center dot center dot N angle: 148.87 degrees) at its backbone. The isomeric [1]ClO4 and [2]ClO4 also exhibit distinctive spectral, electrochemical, electronic structural, and hydrogen bonding features. The pK(a) values for [1]ClO4 and [2]ClO4 have been estimated to be 0.73 and 50 degrees) in paramagnetic [Os-III(bpy)(2)(L'(2-))]ClO4 ([4]ClO4). The electronic structural aspects of the complexes reveal the noninnocent potential of the coordinated HL-, L2-, and L'(2-). The K-c value of 49 for 3(3+) reveals a class I mixed-valent (OsOsIII)-Os-II state.

The compounds [(acac)(2)Ru-III(mu-H2L2-)Ru-III(acac)(2)] (rac, 1, and meso, 1') and [(bpy)(2)Ru-III(mu-H2L center dot-)Ru-III(bpy)(2)](C1O(4))(3) (meso, [2](ClO4)(3)) have been structurally, magnetically, spectroelectrochemically, and computationally characterized (acac(-) = acetylacetonate, bpy = 2,2'-bipyridine, and H4L = 1,4-diamino-9,10-anthraquinone). The N,O;N',O'-coordinated mu-H2Ln- forms two beta-ketiminato-type chelate rings, and 1 or 1' are connected via NH center dot center dot center dot O hydrogen bridges'in the crystals. 1 exhibits a complex magnetic behavior, while [2](ClO4)(3) is a radical species with mixed ligand/metal-based spin. The combination of redox noninnocent bridge (H2L0 -> -> -> -> H2L4-) and {(acac)(2)Ru-II} -> ->{(acac)(2)Ru-IV} or {(bpy)(2)Ru-II} -> {(bpy)(2)Ru-III} in 1/1' or 2 generates alternatives regarding the oxidation state formulations for the accessible redox states (1(n) and 2(n)), which have been assessed by UV-vis-NIR, EPR, and DFT/TD-DFT calculations. The experimental and theoretical studies suggest variable mixing of the frontier orbitals of the metals and the bridge, leading to the following most appropriate oxidation state combinations: [(acac)(2)Ru-III(mu-H2L center dot-)Ru-III(acac)(2)](+) (1(+)) -> [(acac)(2)Ru-III(mu-H2L2-)Ru-III(acac)(2)] (1) -> [(acac)(2)Ru-III mu-H2L center dot 3-)Ru-III(acac)(2)](-)/[(acac)(2)](-) Ru-III(mu-H2L2-)Ru-III(acac)(2)](-) (1(-)) -> [(acac)(2)Ru-III(mu-H2L4-)Ru-III(acac)(2)](2-)/[(acac)(2)Ru-III(mu-H2L2-)Ru-III(acac)(2)](2-) (1(2-)) and {(bpy)(2)Ru-III(mu-H2L2-)Ru-III(bpy)(2)](4+) (2(4+)) -> [(bpy)(2)Ru-III(mu-H2L center dot-)Ru-II(bpy)(2)](3+)/[(bpy)(2)Ru-III(mu-H2L2-)Ru-III(bpy)(2))(3+) (2(3+)) -> [(bpy)(2)Ru-II(mu-H2L2-)Ru-II(bpy)(2)](2+) (2(2+)). The favoring of Ru-III by sigma-donating acac(-) and of Ru-II by the pi-accepting bpy coligands shifts the conceivable valence alternatives accordingly. Similarly, the introduction of the NH donor function in H2Ln as compared to 0 causes a cathodic shift of redox potentials with corresponding consequences for the valence structure.

We thank S. Mitani and O. Bossinger for slcf-1(tm2258) and OLB11 strains, respectively, and the C. elegans Genetics Center, which is funded by the NIH National Center for Research Resources, for other strains used in this work. We are grateful to S. Croze, N. Nazaret, and C. Rey from ProfileXpert, Genomique & Microgenomique, Universite Lyon 1, SFR sante LYON-EST, UCBL-INSERM US 7-CNRS UMS 3453 for gene expression analysis. We also thank Erin Rossini for carefully reading and correcting the manuscript; International audience; Dietary restriction (DR) is one of the most universal means of extending lifespan. Yet, whether and how DR specifically affects the metabolic changes associated with aging is essentially unknown. Here, we present a comprehensive and unbiased picture of the metabolic variations that take place with age at the whole organism level in Caenorhabditis elegans by using H-1 high-resolution magic-angle spinning (HR-MAS) nuclear magnetic resonance (NMR) analysis of intact worms. We investigate metabolic variations potentially important for lifespan regulation by comparing the metabolic fingerprint of two previously described genetic models of DR, the long-lived eat-2(ad465) and slcf1-(tm2258) worms, as single mutants or in combination with a genetic suppressor of their lifespan phenotype. Our analysis shows that significant changes in metabolite profiles precede the major physiological decline that accompanies aging and that DR protects from some of those metabolic changes. More specifically, low phosphocholine (PCho) correlates with high life expectancy. A mutation in the tumor suppressor gene PTEN/DAF-18, which suppresses the beneficial effects of DR in both C. elegans and mammals, increases both PCho level and choline kinase expression. Furthermore, we show that choline kinase function in the intestine can regulate lifespan. This study highlights the relevance of NMR metabolomic approaches for identifying potential biomarkers of aging

Objectives: We determined relationships of the anti-oxidative enzyme, paraoxonase-1 (PON-1), with high density lipoprotein (HDL) subfractions, and tested whether these relationships are stronger than those with HDL cholesterol and apolipoprotein A-I (apoA-I) in subjects with and without type 2 diabetes mellitus (T2DM).Design and methods: Serum PON-1 (arylesterase activity) and HDL subfractions (nuclear magnetic resonance spectroscopy) were determined in 67 T2DM patients and in 56 non-diabetic subjects.Results: PON-1 activity, HDL cholesterol and apoA-Iwere decreased in T2DM (all p Conclusions: PON-1 activity is more closely related to the HDL particle concentration or large HDL particles than to HDL cholesterol. Impaired PON-1 activity in T2DM is not to a considerable extent explained by altered HDL subfraction levels. (C) 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Proto-cooperation between Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus is one of the key factors that determine the fermentation process and final quality of yoghurt. In this study, the interaction between different proteolytic strains of S. thermophilus and L. delbrueckii subsp. bulgaricus was investigated in terms of microbial growth, acidification and changes in the biochemical composition of milk during set-yoghurt fermentation. A complementary metabolomics approach was applied for global characterization of volatile and non-volatile polar metabolite profiles of yoghurt associated with proteolytic activity of the individual strains in the starter cultures. The results demonstrated that only non-proteolytic S. thermophilus (Prt −) strain performed proto-cooperation with L. delbrueckii subsp. bulgaricus. The proto-cooperation resulted in significant higher populations of the two species, faster milk acidification, significant abundance of aroma volatiles and non-volatile metabolites desirable for a good organoleptic quality of yoghurt. Headspace SPME-GC/MS and 1H NMR resulted in the identification of 35 volatiles and 43 non-volatile polar metabolites, respectively. Furthermore, multivariate statistical analysis allows discriminating set-yoghurts fermented by different types of starter cultures according to their metabolite profiles. Our finding underlines that selection of suitable strain combinations in yoghurt starters is important for achieving the best technological performance regarding the quality of product.

Summary Biomacromolecules in solution modify the structure and the dynamics of the bulk water at the solute-solvent interface. The ordering effects of biomolecules, in particular proteins, are extended for several angstroms. The role of the hydration shells around a protein has yet to be completely understood. Hydrated proteins maintain more dynamic flexibility with respect to the dried system, which is an important property in protein-protein and/or protein-ligand recognition processes. In this paper we propose a method for analyzing the dynamical properties of the water molecules present in the hydration shells of proteins. The approach is based on analysis of the effects of protein-solvent interactions on water protons NMR relaxation parameters. The water proton spin-lattice relaxation rate in protein solution is analyzed considering all possible dipolar contributions from coupled protons environments. The analysis of both selective and non-selective water spin-lattice relaxation rates allowed the calculation of the average effective correlation time for the water molecules at the protein interface and the evaluation of the long range ordering effect of the protein surface.

Microporous materials, having pores and channels on the same size scale as small to medium molecules, have found many important applications in current technologies, including catalysis, gas separation and drug storage and delivery. Many of their properties and functions are related to their detailed local structure, such as the type and distribution of active sites within the pores, and the specific structures of these active sites. Solid-state NMR spectroscopy has a strong track record of providing the requisite detailed atomic-level insight into the structures of microporous materials, in addition to being able to probe dynamic processes occurring on timescales spanning many orders of magnitude (i.e., from s to ps). In this Perspective, we provide a brief review of some of the basic experimental approaches used in solid-state NMR spectroscopy of microporous materials, and then discuss some more recent advances in this field, particularly those applied to the study of crystalline materials such as zeolites and metal-organic frameworks. These advances include improved software for aiding spectral interpretation, the development of the NMR-crystallography approach to structure determination, new routes for the synthesis of isotopically-labelled materials, methods for the characterisation of host-guest interactions, and methodologies suitable for observing NMR spectra of paramagnetic microporous materials. Finally, we discuss possible future directions, which we believe will have the greatest impact on the field over the coming years. Postprint

Here we perform a comprehensive study of ultrafast molecular and vibrational dynamics of water confined in small reversed micelles (RMs). The molecular picture is elucidated with two-dimensional infrared (2D IR) spectroscopy of water OH stretch vibrations and molecular dynamics simulations, bridged by theoretical calculations of linear and 2D IR vibrational spectra. To investigate the effects of intermolecular coupling, experiments and modeling are performed for isotopically diluted (HDO in D2O) and undiluted (H2O) water. We put a separation of water inside RMs into two subensembles (water-bound and surfactant-bound molecules), observed by many before, on a solid theoretical basis. Water molecules fully attached to the lipid interface ("shell" water) are decoupled from one another and from the central water nanopool ("core" water). The environmental fluctuations are largely "frozen" for the shell water, while the core waters demonstrate much faster dynamics but still not as fast as in the bulk case. A substantial nanoconfinement effect on the dynamics of the core water is observed after disentanglement of the shell water contribution, which is fully confirmed by the simulations of 2D IR spectra. Current results provide new insights into interaction between biological objects like membranes or proteins with the surrounding aqueous bath, and highlight peculiarities in vibrational energy redistribution near the lipid surface.

The relationship between the properties of geopolymers and the characteristics of metakaolin samples used in their preparation has been investigated. Three commercial metakaolin samples have been characterised using 27Al-NMR to determine the coordination number of Al (IV, V and VI), and by acid and alkali dissolution to determine the reactive Si and Al content. The setting and mechanical properties of geopolymers formed from the metakaolin samples under identical conditions are reported, using Weibull statistics to analyse strength data. Although the metakaolin samples contained different levels of five coordinated aluminium (Al (V)) the mechanical properties of the geopolymers formed were very similar. The reactive fraction of metakaolinite determined by dissolution in 8 M NaOH provides the most relevant long-term indicator of geopolymer performance.

Water-based cellulose cholesteric liquid crystalline phases at rest can undergo structural changes induced by shear flow. This reflects on the deuterium spectra recorded when the system is investigated by rheo-nuclear magnetic resonance (rheo-NMR) techniques. In this work, the model system hydroxypropylcellulose (HPC)+water is revisited using rheo-NMR to clarify unsettled points regarding its behavior under shear and in relaxation. The NMR spectra allow the identification of five different stable ordering states, within shear and relaxation, which are well integrated in a mesoscopic picture of the system’s structural evolution under shear and relaxation. This picture emerging from the large body of studies available for this system by other experimental techniques, accounts well for the NMR data and is in good agreement with the three distinct regions of steady shear flow recognized for some lyotropic LC polymers. Shear rates in between 0.1 and 1.0 s–1 where investigated using a Taylor–Couette flow and de...

Graft copolymers of starch with acrylic acid are a promising green, bio based material with many potential applications. The grafting of acrylic acid onto cassava starch in an aqueous medium initiated by Fenton's reagent has been studied. Common grafting result parameters are add-on (yield) and graft efficiency (selectivity). However, the analysis of the reaction products and an accurate determination of these parameters stand or fall with a complete separation of the entangled but ungrafted homopolymer from the grafted product. Therefore, this separation is the core of the newly developed analytical procedure. An appropriate solvent has been selected with dedicated testing from the range methanol, ethanol, acetone, dioxane, 2-propanol, and 1-propanol. Acetone showed the best performance in many respects. It has a high dissolving power for the homopolymer, as well as the highest yield of precipitation for the starch derivatives and it is the most economical in use. After the successful separation, the precipitated graft copolymers could be analyzed quantitatively by nuclear magnetic resonance. The liquid with homopolymer and unreacted monomer was analyzed by high pressure liquid chromatography. Proof of grafting has been found by FTIR and TGA analyses. The mass balance calculation shows a systematic error which appears fairly consistent: 18.0 +/- 2.5 wt %. This was used as a correction factor in the calculation of the grafting parameters but more importantly, it means that the method we developed has a high level of repeatability, in the order of 97%. (C) 2013 Elsevier Ltd. All rights reserved.

Focusing on the idea that multivalent cations affect SOM matrix and surface, we treated peat and soil samples by solutions of NaCl, CaCl2 or AlCl3. Water binding was characterized with low field 1H-NMR-relaxometry (20 MHz) and 1H wideline NMR spectroscopy (400 MHz) and compared to contact angles. From 1H wideline, we distinguished mobile water and water involved in water molecule bridges (WaMB). Large part of cation bridges (CaB) between SOM functional groups are associated with WaMB. Unexpectedly, 1H NMRrelaxometry relaxation rates suggest that cross-linking in the Al-containing peat is not stronger than that by Ca. The relation between percentage of mobile water and WaMB water in the context of wettability and 1H NMR relaxation times confirms that wettability controls the water film surrounding soil particles. Wettability is controlled by WaMB-CaB associations fixing hydrophilic functional groups in the SOM interior. This can lead to severe water repellency. Wettability decreases with increasing involvement of functional groups in CaB-WaMB associations. The results demonstrate the relevance of CaB and WaMB for the dynamics of biogeochemical and hydrological processes under field conditions, as only a few percent of organic matter can affect the physical, chemical, and biological functioning of the entire 3-phase ecosystem.

In this study, the effect of torrefaction on the chemical and structural transformation of lignocellulosic biomass was investigated using complementary analytical tools. It was observed that the acid-insoluble fraction was increased from approximately 30 to 38% and the methoxyl content was decreased to about half after torrefaction at 330 °C for 2.5 min. These results highlight the formation of condensed structures along with lignin transformation via demethoxylation. Solid-state NMR spectroscopy indicated that upon torrefaction the aromaticity increased from about 36 to 60%. For the sample torrefied at 330 °C, the non-protonated aromatic carbon fraction was found to be about 60% of total aromatic carbons, indicating the formation of large aromatic clusters. The complementary analyses used in this study are proposed as a suitable approach for the elucidation of chemical and structural transformation of biomass during thermal treatment.

Monodisperse water-in-oil-in-water (WOW) double emulsions have been prepared using microfluidic glass devices designed and built primarily from off the shelf components. The systems were easy to assemble and use. They were capable of producing double emulsions with an outer droplet size from 100 to 40 µm. Depending on how the devices were operated, double emulsions containing either single or multiple water droplets could be produced. Pulsed-field gradient self-diffusion NMR experiments have been performed on the monodisperse water-in-oil-in-water double emulsions to obtain information on the inner water droplet diameter and the distribution of the water in the different phases of the double emulsion. This has been achieved by applying regularization methods to the self-diffusion data. Using these methods the stability of the double emulsions to osmotic pressure imbalance has been followed by observing the change in the size of the inner water droplets over time.

In this article, we describe third-spin assisted heteronuclear recoupling experiments, which play an increasingly important role in measuring long-range heteronuclear couplings, in particular (15)N-(13)C, in proteins. In the proton-assisted insensitive nuclei cross polarization (PAIN-CP) experiment (de Paepe et al. in J Chem Phys 134:095101, 2011), heteronuclear polarization transfer is always accompanied by homonuclear transfer of the proton-assisted recoupling (PAR) type. We present a phase-alternating experiment that promotes heteronuclear (e.g. (15)N → (13)C) polarization transfer while simultaneously minimizing homonuclear (e.g.(13)C → (13)C) transfer (PAIN without PAR). This minimization of homonuclear polarization transfer is based on the principle of the resonant second-order transfer (RESORT) recoupling scheme where the passive proton spins are irradiated by a phase-alternating sequence and the modulation frequency is matched to an integer multiple of the spinning frequency. The similarities and differences between the PAIN-CP and this het-RESORT experiment are discussed here.

The previous work on the hydrolysis and alcoholysis reactions of phosphonium ylides is summarized and reviewed in the context of their currently accepted mechanisms. Several experimental facts relating to ylide hydrolysis and to salt and ylide alcoholysis are shown to conflict with those mechanisms. In particular, we demonstrate that the pK(a) values of water and alcohols are too high in organic media to bring about protonation of ylide. Therefore, we propose concerted addition of the water or alcohol O-H bond across the ylide P=C bond. In support of this, we provide NMR spectroscopic evidence for equilibrium between ylide and aclohol that does not require the involvement of phosphonium hydroxide. We report the first P-alkoxyphosphorane to be characterised by NMR spectroscopy that does not undergo exchange on an NMR timescale. Two-dimensional NMR spectroscopic techniques have been applied to the characterisation to P-alkoxyphosphoranes for the first time.

Complex scientific data is becoming the norm, many disciplines are growing immensely data-rich, and higher-dimensional measurements are performed to resolve complex relationships between parameters. Inherently multi-dimensional measurements can directly provide information on both the distributions of individual parameters and the relationships between them, such as in nuclear magnetic resonance and optical spectroscopy. However, when data originates from different measurements and comes in different forms, resolving parameter relationships is a matter of data analysis rather than experiment. We present a method for resolving relationships between parameters that are distributed individually and also correlated. In two case studies, we model the relationships between diameter and luminescence properties of quantum dots and the relationship between molecular weight and diffusion coefficient for polymers. Although it is expected that resolving complicated correlated relationships require inherently multi-dimensional measurements, our method constitutes a useful contribution to the modelling of quantitative relationships between correlated parameters and measurements. We emphasise the general applicability of the method in fields where heterogeneity and complex distributions of parameters are obstacles to scientific insight. Refereed/Peer-reviewed

The unsymmetrical diruthenium complexes [(bpy)(2)Ru-II(mu-H2L2-)Ru-III(acac)(2)]ClO4 ([3]ClO4), [(pap)(2)Ru-II(mu-H2L2-)Ru-III(acac)(2)]ClO4 ([4]ClO4), and [(bpy)(2)Ru-II(mu-H2L2-)-Ru-II(pap)(2)](ClO4)(2) ([5](ClO4)(2)) have been obtained by way of the mononuclear precursors [(bpy)(2)Ru-II(H3L-)]ClO4 ([1]ClO4) and [(pap)(2)Ru-II(H3L-)]ClO4 ([2]ClO4) (where bpy = 2,2'-bipyridine, pap = 2-phenylazopyridine, acac(-) = 2,4-pentanedionate, and H4L = 1,4-diamino-9,10-anthraquinone). Structural characterization by single-crystal X-ray diffraction and magnetic resonance (nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR)) were used to establish the oxidation state situation in each of the isolated materials. Cyclic voltammetry, EPR, and ultraviolet-visible-near-infrared (UV-vis-NIR) spectroelectrochemistry were used to analyze the multielectron transfer series of the potentially class I mixed-valent dinuclear compounds, considering the redox activities of differently coordinated metals, of the noninnocent bridge and of the terminal ligands. Comparison with symmetrical analogues [L'Ru-2(mu-H2L)RuL'(2)](n) (where L' = bpy, pap, or acac(-)) shows that the redox processes in the unsymmetrical dinuclear compounds are not averaged, with respect to the corresponding symmetrical systems, because of intramolecular charge rearrangements involving the metals, the noninnocent bridge, and the ancillary ligands.

International audience; We present a solid-state NMR methodology capable of investigating the carbon skeleton of natural abundance organic powders. The methodology is based on the C-13-C-13 dipolar coupling interaction and allows carbon-carbon connectivities to be unambiguously established for a wide range of organic solids. This methodology is particularly suitable for disordered solids, such as natural or synthetic macromolecules, which cannot be studied using conventional diffraction or NMR techniques.

We present heteronuclear F-19 refocused CW (rCW) decoupling pulse sequences for solid-state magic-angle- spinning NMR applications. The decoupling sequences have been designed specifically to ensure suppression of the pertinent C-13-F-19 dipolar coupling interactions while simultaneously suppressing strong anisotropic chemical shift as well as homonuclear F-19-F-19 dipolar coupling effects as typically present in perfluorated compounds. In an extensive numerical and experimental analysis using a rigid, organic solid as a model compound, it becomes evident that the supercycled rCW schemes markedly improve the decoupling efficiency, leading to substantial enhancements in resolution and sensitivity when compared to previous state-of-the-art methods. Furthermore, considerable gains in robustness toward rf mismatch as well as offset in the radio-frequency carrier frequency are observed, all of which clearly render the new rCW schemes the methods of choice for 19F decoupling in rigid, fluorinated compounds - which is further supported by a Floquet-based theoretical analysis.