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International audience; The effect of the Co-Cu oxide catalysts composition on their physicochemical properties and performance in the deep oxidation of ethanol was studied. The catalysts with Co:Cu molar ratios of 4:1, 1:1, and 1:4 were obtained by calcination (4 h at 500 °C in air) of the coprecipitated precursors and characterized in detail using powder XRD, Raman spectroscopy, N2 physisorption, H2-TPR, and XPS. The powder XRD and Raman spectroscopy indicated the formation of Co3O4 and CuO mixtures rather than Co-Cu mixed oxides. The CuO promoted the Co3O4 reduction; the Co-Cu catalysts were reduced more easily than the single-component Co and Cu oxides and the main reduction maxima were shifted to lower temperatures with increasing cobalt content in the catalysts. The Co-Cu oxide catalyst with a Co:Cu molar ratio of 4:1 exhibited the best performance in ethanol gas-phase oxidation, showing the lowest T50 (91 °C) and T90(CO2) (159 °C) temperatures needed for 50% ethanol conversion and 90% conversion to CO2, respectively. The excellent catalytic properties of this Co-Cu oxide catalyst were ascribed to the synergistic effect of Co and Cu components. The high activity and selectivity of the Co-Cu catalyst was attributed to the presence of finely dispersed CuO particles on the surface of Co3O4.; L'effet de la composition des catalyseurs à base d'oxyde de Co-Cu sur leurs propriétés physicochimiques et leur performance dans l'oxydation profonde de l'éthanol a été étudié. Les catalyseurs avec des rapports molaires Co:Cu de 4:1, 1:1 et 1:4 ont été obtenus par calcination (4 h à 500 °C dans l'air) des précurseurs coprécipités et caractérisés en détail à l'aide de la XRD des poudres, de la spectroscopie Raman, de la physisorption de N2, de la H2-TPR et de la XPS. La DRX des poudres et la spectroscopie Raman ont indiqué la formation de mélanges de Co3O4 et de CuO plutôt que d'oxydes mixtes Co-Cu. Le CuO a favorisé la réduction du Co3O4 ; les catalyseurs Co-Cu ont été réduits plus facilement que les oxydes de Co et de Cu à composant unique et les principaux maxima de réduction ont été déplacés vers des températures plus basses avec l'augmentation de la teneur en cobalt dans les catalyseurs. Le catalyseur à base d'oxyde de Co-Cu avec un rapport molaire Co:Cu de 4:1 a présenté les meilleures performances dans l'oxydation de l'éthanol en phase gazeuse, affichant les températures T50 (91 °C) et T90(CO2) (159 °C) les plus basses nécessaires à la conversion de 50 % de l'éthanol et à la conversion de 90 % en CO2, respectivement. Les excellentes propriétés catalytiques de ce catalyseur à base d'oxyde de Co-Cu ont été attribuées à l'effet synergique des composants Co et Cu. L'activité et la sélectivité élevées du catalyseur Co-Cu ont été attribuées à la présence de particules de CuO finement dispersées à la surface du Co3O4.

Ceramides (Cers) with ultralong (∼32-carbon) chains and ω-esterified linoleic acid, composing a subclass called omega-O-acylceramides (acylCers), are indispensable components of the skin barrier. Normal barriers typically contain acylCer concentrations of ∼10 mol%; diminished concentrations, along with altered or missing long periodicity lamellar phase (LPP), and increased permeability accompany an array of skin disorders, including atopic dermatitis, psoriasis, and ichthyoses. We developed model membranes to investigate the effects of the acylCer structure and concentration on skin lipid organization and permeability. The model membrane systems contained six to nine Cer subclasses as well as fatty acids, cholesterol, and cholesterol sulfate; acylCer content-namely, acylCers containing sphingosine (Cer EOS), dihydrosphingosine (Cer EOdS), and phytosphingosine (Cer EOP) ranged from zero to 30 mol%. Systems with normal physiologic concentrations of acylCer mixture mimicked the permeability and nanostructure of human skin lipids (with regard to LPP, chain order, and lateral packing). The models also showed that the sphingoid base in acylCer significantly affects the membrane architecture and permeability and that Cer EOP, notably, is a weaker barrier component than Cer EOS and Cer EOdS. Membranes with diminished or missing acylCers displayed some of the hallmarks of diseased skin lipid barriers (i.e., lack of LPP, less ordered lipids, less orthorhombic chain packing, and increased permeability). These results could inform the rational design of new and improved strategies for the barrier-targeted treatment of skin diseases.

Ceramides (Cers) with α-hydroxylated acyl chains comprise about a third of all extractable skin Cers and are required for permeability barrier homeostasis. We have probed here the effects of Cer hydroxylation on their behavior in lipid models comprising the major SC lipids, Cer/free fatty acids (C 16-C 24)/cholesterol, and a minor component, cholesteryl sulfate. Namely, Cers with (R)-α-hydroxy lignoceroyl chains attached to sphingosine (Cer AS), dihydrosphingosine (Cer AdS), and phytosphingosine (Cer AP) were compared to their unnatural (S)-diastereomers and to Cers with non-hydroxylated lignoceroyl chains attached to sphingosine (Cer NS), dihydrosphingosine (Cer NdS), and phytosphingosine (Cer NP). By comparing several biophysical parameters (lamellar organization by X-ray diffraction, chain order, lateral packing, phase transitions, and lipid mixing by infrared spectroscopy using deuterated lipids) and the permeabilities of these models (water loss and two permeability markers), we conclude that there is no general or common consequence of Cer α-hydroxylation. Instead, we found a rich mix of effects, highly dependent on the sphingoid base chain, configuration at the α-carbon, and permeability marker used. We found that the model membranes with unnatural Cer (S)-AS have fewer orthorhombically packed lipid chains than those based on the (R)-diastereomer. In addition, physiological (R)-configuration decreases the permeability of membranes, with Cer (R)-AdS to theophylline, and increases the lipid chain order in model systems with natural Cer (R)-AP. Thus, each Cer subclass makes a distinct contribution to the structural organization and function of the skin lipid barrier.

Supported catalysts with Co3O4 deposited on stainless steel wire meshes were prepared and examined in the total oxidation of ethanol. Combination of reactive magnetron sputtering of cobalt particles in oxidation Ar + O2 atmosphere and electrochemical formation of cobalt hydroxide precursors using cathodic reduction of cobalt nitrate in aqueous solution was applied for coating of the supports; the precursors were then transformed to Co3O4 by subsequent heating at 500 °C in air. Two plasma enhanced PVD methods, namely the radio-frequency (RF) magnetron sputtering and high-power impulse magnetron sputtering (HiPIMS) were used for obtaining of Co3O4 thin films. The catalysts prepared using RF magnetron sputtering were more active than analogous catalysts prepared using the HiPIMS process. The catalyst obtained by electrochemical deposition on a bare stainless steel mesh had the highest Co3O4 loading and showed the highest efficiency in total ethanol oxidation. Rather poor adhesion of the cobalt oxide layer prepared by electrochemical deposition on stainless steel mesh covered with Co3O4 thin films was significantly improved, when the catalysts were coated with additional Co3O4 thin film by magnetron sputtering. The highest specific catalytic activity and the best adhesion of Co3O4 layer to the stainless steel support was found for the RF-ED-RF catalyst prepared by combination of RF magnetron sputtering and electrochemical deposition. The activity of all supported catalysts, containing about 1 wt. % of Co3O4, in the total oxidation of ethanol to CO2 was better than that of the pelletized commercial Co3O4, though the cobalt oxide content in the bed of supported catalysts was nearly 50 times lower.

Membrane models of the stratum corneum (SC) lipid barrier, either healthy or affected by recessive X-linked ichthyosis, constructed from ceramide [Cer; nonhydroxyacyl sphingosine N-tetracosanoyl-d-erythro-sphingosine (CerNS24) alone or with omega-O-acylceramide N-(32-linoleyloxy)dotriacontanoyl-d-erythro-sphingosine (CerEOS)], FFAs(C16–24), cholesterol (Chol), and sodium cholesteryl sulfate (CholS) were investigated. X-ray diffraction (XRD) revealed a previously unreported polymorphism of the membranes. In the absence of CerEOS, the membranes formed a short lamellar phase (SLP; the repeat distance d = 5.3 nm), a medium lamellar phase (MLP; d = 10.6 nm), or very long lamellar phases (VLLP; d = 15.9 and 21.2 nm). An increased CholS-to-Chol ratio modulated the membrane polymorphism, although the CholS phase separated at ≥ 7 weight% (of total lipids). The presence of CerEOS led to the stable long lamellar phase (LLP) with d = 12.2 nm and prevented VLLP formation. Our XRD results agree well with recently published cryo-electron microscopy data for vitreous skin sections, while also revealing new structures. Thus, lamellar phases with long repeat distances (MLP and VLLP) may be formed in the absence of omega-O-acylceramide, whereas these ultralong Cer species likely stabilize the final SC lipid architecture of LLP by riveting the adjacent lipid layers.

Orthocuproplatinum, Pt3Cu, is a new mineral from the Lubero region of North Kivu, Democratic Republic of the Congo. The mineral, which has a synthetic analogue, occurs as a 1.5-mm-long alluvial grain in a heavy-mineral concentrate, together with the holotype specimen of kitagohaite, Pt7Cu. The grain of orthocuproplatinum has a rim of hongshiite, PtCu, and abundant inclusions of calcite. Opaque and metallic, orthocuproplatinum has a whitish colour in reflected light and slightly perceptible anisotropy. The crystal structure of orthocuproplatinum is orthorhombic, space group Cmmm. Its unit-cell parameters: a = 7.681(1) A; b = 5.4318(8) A; c = 2.7502(4) A; V = 114.74(3) A3; Z = 2. The calculated density is 17.866 g cm−3. The strongest diffraction lines are [d in A(I)]: 2.337 (11), 2.236 (100), 2.217 (97), 1.932 (61), 1.920 (30), 1.362 (36), 1.169 (24), 1.161 (23). The Vickers hardness is 243 kg mm−2 (VHN25), corresponding to a Mohs hardness of 4. The empirical formula of orthocuproplatinum, calculated from a mean value of 12 electron-probe microanalyses that gave 12.9 wt% Cu and 87.3 wt% Pt, is Pt2.76Cu1.24 on the basis of 4 atoms.

TiO2 films were prepared via a two-step fabrication process, i.e. deposition of Ti films by magnetron sputtering on an FTO glass substrate followed by thermal oxidation at 600–725 °C. The investigated parameters were Ti layer thickness, temperature of oxidation and deposition conditions (pre-treatment and substrate heating). Such TiO2 films have a rutile structure and contain metallic Sn which is the result of a thermal reaction at the interface between SnO2 and Ti at temperatures above 500 °C. A calcination temperature of 600 °C is optimal for fabricating TiO2 films with significant photoelectrochemical response. Heating of the FTO substrate during magnetron sputtering deposition of Ti films results in a significant improvement of the compactness of the TiO2 films. A similar but not so pronounced improvement was observed for the TiO2 films deposited on the FTO substrate pre-treated with radio-frequency plasma under Ar–O2 and N2–H2 atmosphere. The observed correlation between the increased content of Sn in the TiO2 films and compactness of the TiO2 films supports the explanation of both positive effects by better adhesion of the Ti films to the FTO substrate.

The reinvestigation of tetrazene single crystalline material by means of X-ray methods resulted in a slightly different structure when compared to previously published data. Reaction conditions responsible for different crystalline modification formation were investigated. Newly described C form was found to be the primary reaction product and the combined action of temperature and the presence of water over time is required for the transition to the A form. Both forms were described by X-ray powder diffraction. Tetrazene was also subjected to infrared and Raman spectroscopy, which allowed differentiating between the forms. The molecule was isotopically labeled with 15N atoms at two different locations (ring and nitrogen sidechain) and employed in assigning vibrational modes to the resulting bands. Differences between sensitivities to mechanical stimuli of the two modifications were investigated and found industrially insignificant. In the same vein, the performance of either modification in primer composition and primer was identical. Opětovné zkoumání tetrazenového monokrystalu pomocí rentgenových metod vedlo k mírně odlišné struktuře ve srovnání s dříve publikovanými údaji. Byly zkoumány reakční podmínky zodpovědné za odlišný vznik krystalických modifikací. Bylo zjištěno, že nově popsaná forma C je primárním reakčním produktem a pro přechod na formu A je nutné kombinované působení teploty a přítomnosti vody v čase. Obě formy byly popsány pomocí rentgenové práškové difrakce. Tetrazen byl rovněž podroben infračervené a Ramanově spektroskopii, což umožnilo formy rozlišit. Molekula byla izotopicky značena atomy 15N na dvou různých místech (kruh a postranní dusíkatý řetězec) a využita při přiřazování vibračních módů výsledným pásům. Byly zkoumány rozdíly mezi citlivostí obou modifikací na mechanické podněty, které byly shledány jako průmyslově nevýznamné. Podobně pak byla i funkčnost obou modifikací v zápalkových složích a zápalkách identická.

Fluorine doped tin oxide layers (F:SnO2, “FTO”) on glass were electrochemically reduced and the resulting layers of tin were re-oxidized. By electrochemical re-oxidation, tetragonal SnO2 was obtained, whereas thermal oxidation led to orthorhombic SnO2. The reconstructed SnO2 was resistive and showed an increase of roughness and porosity compared to the initial smooth and dense FTO. The double layer capacity indicated an increase in the electrochemically active surface area.

Omega-O-acylceramides (acylCer), a subclass of sphingolipids with an ultralong N-acyl chain (from 20 to 38 carbons, most usually 30 and 32 carbons), are crucial components of the skin permeability barrier. AcylCer are involved in the formation of the long periodicity lamellar phase (LPP, 12-13 nm), which is essential for preventing water loss from the body. Lower levels of acylCer and LPP accompany skin diseases, such as atopic dermatitis, lamellar ichthyosis, and psoriasis. We studied how the concentration and structure of acylCer influence the organization and permeability barrier properties of model lipid membranes. For simple model membranes composed of the sphingosine-containing acylCer (EOS), N-lignoceroyl sphingosine, lignoceric acid, cholesterol (Chol), and cholesteryl sulfate (CholS), the LPP formed at 10% Cer EOS (of the total Cer) and the short periodicity phase disappeared at 30% Cer EOS. Surprisingly, membranes with the LPP had higher permeabilities than the control membrane without acylCer. In the complex models consisting of acylCer (EOS, phytosphingosine EOP, dihydrosphingosine EOdS, or their mixture; at 10% of the total Cer), a six-component Cer mixture, a free fatty acid mixture, cholesterol (Chol), and cholesteryl sulfate (CholS), acylCer decreased the membrane permeability to model permeants (with the strongest effects for acylCer EOP and EOdS) when compared with the permeability of the control membrane without acylCer. However, in the complex model, only a mixture of acylCer EOS, EOdS, and EOP and not the individual acylCer formed both the LPP and orthorhombic chain packing at the 10% level. Thus, the relationships between acylCer, LPP formation, and permeability barrier function are not trivial. Lipid heterogeneity is essential-only the most complex model with nine Cer subclasses mimicked both the organization and permeability of stratum corneum lipid membranes.

One dimensional ZnO nanostructures prepared by favorable and simple solution growth methods are at the forefront of this research. Vertically oriented ZnO nanorods with uniform physical properties require high-quality seed layers with a narrow size distribution of the crystallites, strong c-axis orientation, and low surface roughness and porosity. It has been shown that high quality seed layers can be prepared by the sol&ndash, gel process. The sol&ndash, gel process involves three essential steps: preparation of the sol, its deposition by dip coating, and thermal treatment comprising preheating and annealing. We put emphasis on the investigation of the heat treatment on the properties of the seed layers and on the vertical alignment of the nanorods. It was demonstrated that for the vertical alignment of the nanorods, the preheating step is crucial and that the temperatures reported in the literature have been too low. With higher preheating temperatures, conditions for the vertical alignment of the nanorods were achieved in both investigated annealing atmospheres in air and in argon.

Ceramides (Cers) with ultralong (∼32-carbon) chains and ω-esterified linoleic acid, composing a subclass called omega-O-acylceramides (acylCers), are indispensable components of the skin barrier. Normal barriers typically contain acylCer concentrations of ∼10 mol%; diminished concentrations, along with altered or missing long periodicity lamellar phase (LPP), and increased permeability accompany an array of skin disorders, including atopic dermatitis, psoriasis, and ichthyoses. We developed model membranes to investigate the effects of the acylCer structure and concentration on skin lipid organization and permeability. The model membrane systems contained six to nine Cer subclasses as well as fatty acids, cholesterol, and cholesterol sulfate; acylCer content—namely, acylCers containing sphingosine (Cer EOS), dihydrosphingosine (Cer EOdS), and phytosphingosine (Cer EOP) ranged from zero to 30 mol%. Systems with normal physiologic concentrations of acylCer mixture mimicked the permeability and nanostructure of human skin lipids (with regard to LPP, chain order, and lateral packing). The models also showed that the sphingoid base in acylCer significantly affects the membrane architecture and permeability and that Cer EOP, notably, is a weaker barrier component than Cer EOS and Cer EOdS. Membranes with diminished or missing acylCers displayed some of the hallmarks of diseased skin lipid barriers (i.e., lack of LPP, less ordered lipids, less orthorhombic chain packing, and increased permeability). These results could inform the rational design of new and improved strategies for the barrier-targeted treatment of skin diseases.

TiO2 films were prepared via a two-step fabrication process, i.e. deposition of Ti films by magnetron sputtering on an FTO glass substrate followed by thermal oxidation at 600-725 °C. The investigated parameters were Ti layer thickness, temperature of oxidation and deposition conditions (pre-treatment and substrate heating). Such TiO2 films have a rutile structure and contain metallic Sn which is the result of a thermal reaction at the interface between SnO2 and Ti at temperatures above 500 °C. A calcination temperature of 600 °C is optimal for fabricating TiO2 films with significant photoelectrochemical response. Heating of the FTO substrate during magnetron sputtering deposition of Ti films results in a significant improvement of the compactness of the TiO2 films. A similar but not so pronounced improvement was observed for the TiO2 films deposited on the FTO substrate pre-treated with radio-frequency plasma under Ar-O2 and N2-H2 atmosphere. The observed correlation between the increased content of Sn in the TiO2 films and compactness of the TiO2 films supports the explanation of both positive effects by better adhesion of the Ti films to the FTO substrate.

New chiral imide-oxazoline derivatives of Kemp’s acid were synthesized with the aim to produce new ligands suitable for catalytic asymmetric reactions. Compound 1 is C18H28N2O3, systematic name (1R, 5S, 7R)-7-[(S)-4-tert-butyl-4,5-dihydrooxazole-2-yl]-1,5,7-trimethyl-3-azabicyclo-[3.3.1]-nonane-2,4-dione. Compound 2 is C21H26N2O3, systematic name (1R,5S,7R)-7-[(S)-4-benzyl-4,5-dihydrooxazole-2-yl]-1,5,7-trimethyl-3-azabicyclo-[3.3.1]-nonane-2,4-dione. Both compounds contain two molecules with very similar conformations in the asymmetric unit. The two structures were characterized by single crystal X-ray diffraction. DFT calculations of two possible distinct conformations were performed to elucidate the differences between the preferred conformation in vacuo and the one observed in the single crystal. Also, charges on the key atoms of the compounds were compared with a common ligand used for asymmetric transfer hydrogenation.

X-ray powder diffraction data, unit-cell parameters, and space group for a new memantine analogue of a Platinum (Pt) (II) complex labelled LA-13, C12H24Cl2N2Pt, are reported [a = 8.324(1) Å, b = 27.838(2) Å, c = 7.113(1), β = 111.25(1), unit-cell volume V = 1536.26 Å3, Z = 4, and space group P21/n]. All measured lines were indexed and are consistent with the P21/n space group. No detectable impurity was observed.

A method for enantioselective hydrogenation of cyclic imines with gaseous hydrogen has been developed. Easily accessible Noyori-Ikariya Ru(II) and Rh(III) complexes can be used directly without an inert atmosphere. Substrate activation has been achieved by trifluoroacetic acid. A new hydroxyl-functionalized complex is reported, showing high activity in transfer hydrogenation.

X-ray powder diffraction data, unit-cell parameters, and space group for acetamidinium formate, C3H8N2O2, are reported [a = 6.4564(5) Å, c = 13.021 (3) Å, unit-cell volume V = 542.8(3) Å3, M.p. = 215(1)°C, ρc = 1.274 g.cm−3, ρm = 1.269 g.cm−3, Z = 4, and space group P43212]. The front-loaded technique got sample with strong preferred orientation because of plate-like shape of crystallites, so the capillary packing was used for final powder data collection. All measured lines were indexed and are consistent with the P43212 space group. No detectable impurities were observed.

X-ray powder diffraction data, unit-cell parameters and space group for 2-(ethylamino)-2-(3-methoxyphenyl)cyclohexan-1-one hydrochloride, C15H22ClNO2, are reported [a = 8.574(2) Å, b = 9.943(2) Å, c = 8.774(1) Å, β = 100.294(3)°, unit-cell volume V = 736(1) Å3, Z = 2, and space-group P21]. All measured lines were indexed and are consistent with the P21 space group. No detectable impurities were observed.

X-ray powder diffraction data, unit-cell parameters, and space group for S-2-(methylamino)-2-phenylcyclohexan-1-one hydrochloride, C13H18ClNO, are reported [a = 6.578 (1) Å, b = 13.250 (2) Å, c = 15.096 (2) Å, β = 91.619 (3)°, unit-cell volume V = 1315(1) Å3, Z = 4, and space group P21]. All measured lines were indexed and are consistent with the P21 space group. No detectable impurities were observed.

Ceramides (Cer) are key components of the skin permeability barrier. Sphingosine-based CerNS and dihydrosphingosine-based CerNdS (dihydroCer) have two chiral centers; however, the importance of the correct stereochemistry in the skin barrier Cer is unknown. We investigated the role of the configuration at C-3 of CerNS and CerNdS in the organization and permeability of model skin lipid membranes. Unnatural l-threo-CerNS and l-threo-CerNdS with 24-C acyl chains were synthesized and, along with their natural d-erythro-isomers, incorporated into membranes composed of major stratum corneum lipids (Cer, free fatty acids, cholesterol, and cholesteryl sulfate). The membrane microstructure was investigated by X-ray powder diffraction and infrared spectroscopy, including deuterated free fatty acids. Inversion of the C-3 configuration in CerNS and CerNdS increased phase transition temperatures, had no significant effects on lamellar phases, but also decreased the proportion of orthorhombic packing and decreased lipid mixing in the model membranes. These changes in membrane organization resulted in membrane permeabilities that ranged from unchanged to 5-fold higher (depending on the permeability markers, namely, water loss, electrical impedance, flux of theophylline, and flux of indomethacin) compared to membranes with natural CerNS/NdS isomers. Thus, the physiological d-erythro stereochemistry of skin Cer and dihydroCer appears to be essential for their correct barrier function.

The crystal structure of the organic mineral refikite has been determined. The mineral was found in joints in bark and wood from pine trees in the 'V Borkách' peat deposit near the town of Krásno, Slavkovský les Mountains, western Bohemia, Czech Republic. It forms white to light-yellow polycrystalline crusts or randomly intergrown, transparent, colourless, very thin, acicular crystals up to 0.2–0.5 mm long. Sometimes, colourless-to-white elongated prismatic crystals up to 1–1.5 mm in size were encountered. The mineral is soft (Mohs hardness ∼1) and very brittle, with an uneven fracture. No visible cleavage was discerned. Crystals have a greasy-to-glassy lustre; fine crystal aggregates have a pearly lustre. Refikite, empirical formula C20H34O2 or C19H33COOH, is a derivative of abietic acid. It is orthorhombic, space group P21212, with a = 22.6520(7), b = 10.3328(3), c = 7.6711(2) Å, V = 1795.49(9) Å3, Z = 4. Refikite comprises two closely related compounds based on perhydrophenanthrene. The major component has two axial methyl groups, one terminal carboxylic group and one terminal propan-2-yl (isopropyl) group joined to the three fused rings in the same fashion as in abietic acid. However, the fused ring system is fully reduced (contains single bonds only). In the minor component, the terminal propan-2-yl group is replaced by a propen-2-yl (methylvinyl) group. The crystal structure is stabilized by strong O···H–O hydrogen bonds. High-resolution mass spectroscopy (HRMS) confirmed a molecular mass of 306 and the formula C20H34O2. Hydrogen-1 and carbon-13 nuclear magnetic resonance (NMR) spectroscopy showed the presence of four methyl groups in the major component; infrared (IR), Raman and NMR spectra are consistent with the structure. The HRMS, IR and Raman spectroscopy methods confirmed the presence of a minor component containing the propen-2-yl group replacing the propan-2-yl group. This is also reflected in a shortened C15–C17 single bond metric of 1.468(6) Å shown by single-crystal X-ray analysis. The trivial name of the major component of refikite is tetrahydroabietic acid or abietan-18-oic acid. This work represents the first proof of the existence of abietic acid derivatives as naturally occurring species.

Ceramides (Cer) based on 6-hydroxysphingosine are important components of the human skin barrier, the stratum corneum. Although diminished concentrations of 6-hydroxyCer have been detected in skin diseases such as atopic dermatitis, our knowledge on these unusual sphingolipids, which have only been found in the skin, is limited. In this work, we investigate the biophysical behavior of N-lignoceroyl-6-hydroxysphingosine (Cer NH) in multilamellar lipid membranes composed of Cer/free fatty acids (FFAs) (C16-C24)/cholesterol/cholesteryl sulfate. To probe the Cer structure-activity relationships, we compared Cer NH membranes with membranes containing Cer with sphingosine (Cer NS), dihydrosphingosine, and phytosphingosine (Cer NP), all with the same acyl chain length (C24). Compared with Cer NS, 6-hydroxylation of Cer not only increased membrane water loss and permeability in a lipophilic model compound but also dramatically increased the membrane opposition to electrical current, which is proportional to the flux of ions. Infrared spectroscopy revealed that Cer hydroxylation (in either Cer NH or Cer NP) increased the main transition temperature of the membrane but prevented good Cer mixing with FFAs. X-ray powder diffraction showed not only lamellar phases with shorter periodicity upon Cer hydroxylation but also the formation of an unusually long periodicity phase (d = 10.6 nm) in Cer NH-containing membranes. Thus, 6-hydroxyCer behaves differently from sphingosine- and phytosphingosine-based Cer. In particular, the ability to form a long-periodicity lamellar phase and highly limited permeability to ions indicate the manner in which 6-hydroxylated Cer contribute to the skin barrier function.

The porous structure of electrospun TiO 2 nanofibers was characterized in-depth and the best performing nanofiber structure for application in dye sensitized solar cell was identified. Four types of TiO 2 nanofibers were investigated (electrospun from polyvinylpyrrolidone (PVP) and hydroxypropylcellulose (HPC) as templates) with diameters 100–280 nm and surface areas 9–100 m 2 /g. Mesoporous TiO 2 films were prepared by supramolecular templating with a block copolymer Pluronic P123. For the preparation of composite nanofiber mesoporous films, 2% or 15% of electrospun nanofibers were added. Incorporation of nanofibers into the mesoporous film results in a decrease in dye N719 adsorption but at the same time in an increase of roughness factor. Solar efficiency of composite mesoporous films increases (unlike for pure mesoporous films) even for layer thickness higher than 2.3 μm. Thus we developed a simplified method for the preparation of thick mesoporous nanofiber electrodes with improved solar efficiency of 5.51% which outperforms that of pure mesoporous film (4.96%).

The Stratum corneum (SC) prevents water loss from the body and absorption of chemicals. SC intercellular spaces contain ceramides (Cer), free fatty acids (FFA), cholesterol (Chol) and cholesteryl sulfate (CholS). Cer with "very long" acyl chains (for example, N-lignoceroyl-sphingosine, CerNS24) are important for skin barrier function, whereas increased levels of "long" acyl Cer (for example, N-palmitoyl-sphingosine, CerNS16) occur in patients suffering from atopic eczema or psoriasis. We studied the impact of the replacement of CerNS24 by CerNS16 on the barrier properties and microstructure of model SC lipid membranes composed of Cer/FFA/Chol/CholS. Membranes containing the long CerNS16 were significantly more permeable to water (by 38-53%), theophylline (by 50-55%) and indomethacin (by 83-120%) than those containing the very long CerNS24 (either with lignoceric acid or a mixture of long to very long chain FFA). Langmuir monolayers with CerNS24 were more condensed than with CerNS16 and atomic force microscopy showed differences in domain formation. X-ray powder diffraction revealed that CerNS24-based membranes formed one lamellar phase and separated Chol, whereas the CerNS16-based membranes formed up to three phases and Chol. These results suggest that replacement of CerNS24 by CerNS16 has a direct negative impact on membrane structure and permeability.

This paper deals with the investigation of optical and electrical properties of Co3O4. Their impact on catalytic activity in ethanol dehydrogenation is observed. The change in conductivity is provided by intentionally heating the samples in-situ, variation of oxygen flow rate, introduction of the forming gas (10% H2 in N2) and the application of different deposition regimes. Pure Co3O4, as well as deposited catalysts under a forming gas atmosphere are studied. The deposition of the samples on glass and stainless steel substrates is carried out by means of magnetron sputtering. Both radio-frequency and high power impulse magnetron sputtering deposition technologies are applied. By means of these deposition regimes we managed to obtain films with different conductivity and crystalline structure. The morphology of the films is studied by scanning electron microscopy. The crystalline structure and the surface chemical composition of Co3O4 are investigated using X-ray diffraction and X-ray photoelectron spectroscopy. Electrical and optical properties of catalysts are studied by resistance and optical spectroscopy measurements. The catalytic activity of the films is tested on the reaction of ethanol dehydrogenation by means of selected ion flow-drift tube mass spectrometry.

X-ray powder diffraction data, unit-cell parameters and space group for C8H20CuN10O8 are presented [a = 5.262 (2) Å, b = 14.051 (3) Å, c = 12.183 (3) Å, β = 96.912 (5)°, unit-cell volume V = 894.3 Å3, Z = 2, space group P21/n]. All measured lines were indexed and are consistent with the P21/n space group. No detectable impurities were observed.

A new [Ru(II)( η 6 - p -cymene)(1 R ,2 R )- N -((1 S ,2 S )-borneol-10-sulfonyl)-1,2-diphenylethylenediamine] catalyst for the asymmetric transfer hydrogenation of both 1-alkyl and 1-aryl dihydroisoquinolines has been isolated. For the first time in this type of reaction, the catalyst employs an N-alkylsulfonyl group instead of N-arylsulfonyl.

A series of 10-arylflavins (10-phenyl-, 10-(2',6'-dimethylphenyl)-, 10-(2',6'-diethylphenyl)-, 10-(2',6'-diisopropylphenyl)-, 10-(2'-tert-butylphenyl)-, and 10-(2',6'-dimethylphenyl)-3-methylisoalloxazine (2 a-f)) was prepared as potentially nonaggregating flavin photocatalysts. The investigation of their structures in the crystalline phase combined with (1)H-DOSY NMR spectroscopic experiments in CD(3)CN, CD(3)CN/D(2)O (1:1), and D(2)O confirm the decreased ability of 10-arylflavins 2 to form aggregates relative to tetra-O-acetyl riboflavin (1). 10-Arylflavins 2 a-d do not interact by π-π interactions, which are restricted by the 10-phenyl ring oriented perpendicularly to the isoalloxazine skeleton. On the other hand, N3-H⋅⋅⋅O hydrogen bonds were detected in their crystal structures. In the structure of 10-aryl-3-methylflavin (2 f) with a substituted N3 position, weak C-H⋅⋅⋅O bonds and weak π-π interactions were found. 10-Arylflavins 2 were tested as photoredox catalysts for the aerial oxidation of 4-methoxybenzyl alcohol to the corresponding aldehyde (model reaction), thus showing higher efficiency relative to 1. The quantum yields of 4-methoxybenzyl alcohol oxidation reactions mediated by arylflavins 2 were higher by almost one order of magnitude relative to values in the presence of 1.

A- and B-wheat starch (in native or acetylated form) and potato starch (slightly acetylated) were subjected to benzylation with benzylchloride in various reaction conditions and at various reaction times (40–100°C, 1–90 h). Modified and original starches were characterized by elemental analysis and spectroscopic methods (FT-IR and 1H NMR). The semicrystalline or amorphous character was indicated by X-ray powder (XRD) patterns. Rheological properties of benzyl starch of DS ∼ 1 were measured by small amplitude oscillation shear rheology (SAOS) using the rheometer Haake Rheostress RS 80. The results indicated predominantly elastic behavior because the storage modulus was higher than the loss modulus over the whole frequency range; it corresponded to a true gel. The storage and loss moduli increased with increasing frequency while the tangent of phase did not change and was approximately δ = 40°.

The title compound 1, cis-[diiodo(1R,2R)-1,2-diaminocyclohexane-κN,κN′]platinum(II), a precursor of a novel platinum-based anticancer complex, was synthesized. High purity (>99%) was determined by HPLC–UV/VIS and its structure was characterized by LC–ESI–MS, FT-IR and X-ray single-crystal diffraction. The molecules of the title compound interact via N–H···I and C–H···I intermolecular (ultra)-long hydrogen–iodine (acceptor) bonds (distances up to 3.1 A). The crystal structure of the title compound 1 was compared to the structure calculated on the basis of density function theory (DFT). The calculated and measured data varied by a maximum of 0.09 A in bond lengths and the maximum deviation between the compared angles were less than 2°. Experimentally measured bond lengths in the crystal were observed to be reduced when compared to the theoretical calculation. This was caused by both steric requirements of individual structural units and the presence of hydrogen bonds in real sample, which were confirmed by FT-IR (new bands as well as the band shifts to lower wavelengths).

X-ray powder diffraction data, unit cell parameters, and space group for a new platinum-based anticancer complex cis-[bis(acetonitrile)]-[(1R,2R)-1,2-diaminocyclohexane-κN, κN′]platinum (II)nitrate (1:2) monohydrate, cis-[Pt(C2H3N)2(C6H14N2)](NO3)2·H2O, are presented [a=12.638(3) Å, b=12.153(2) Å, c=11.881(3) Å, β=95.145(4)°, space group P21, cell volume=1817.5 Å3, and Z=4]. All measured lines were indexed and are consistent with the P21 space group. No detectable impurities were observed.

Simvastatin is a substance used for the treatment of hypercholesterolemia. In addition to the already known room temperature structure of simvastatin (Cejka et al. in Acta Cryst C59:o428, 2003) two new low-temperature polymorphs were found by X-ray powder diffraction with the phase transition at 261 and 223 K (later confirmed by DSC to be 272 and 232 K). The main differences among three polymorphs consist in the side-chains conformation only and the phase changes are fully reversible. The structures of the polymorphs were studied by the powder diffraction based on synchrotron radiation as well as by solid-state NMR spectroscopy.

Lead iodide PbI2 is an excellent and interesting candidate for high efficiency room temperature detectors working in the medium energy range of 1 keV–1 MeV. It can be widely applied in medicine, monitoring ecology, nondestructive defectoscopy and X-ray and gamma spectroscopy. The peculiarities of this material are high resistivity, ability to work in a wide range of temperatures and high chemical stability. The method of preparation was direct synthesis from lead and iodine. The material was further purified by zone melting and grown by Bridgman-Stockbarger method. In this work we have concentrated on the study of the influence of dopants such as lanthanides (Er,Gd, Ho, Tb, Tm, Yb, GdI3, HoI3, GdI3) and elements of other groups, such as Au, Ag, Ge on the physical, electrical and optical properties of the PbI2. These were evaluated by resistivity and low temperature photoluminescence measurements. The Synchrotron X-ray topography was successfully introduced to study defects. The quality of the material was analyzed after synthesis, zone melting and growth. The dependence on the concentration of dopants was investigated too.

The effect of sodium, calcium, and magnesium chlorides deposited on zinc and carbon steel surfaces was studied under atmospheric conditions. The cations strongly affected the corrosion rate of zinc, whereas they had a significantly lower impact on the corrosion of carbon steel. The corrosivity of cations of chloride salts for zinc increased in order of Mg 2+ 2+ + . The higher corrosion resistance of zinc treated with calcium and magnesium chlorides was connected to prevention of formation of hydrozincite during zinc exposure in wet air. It was observed that zinc weight loss and the carbonate to simonkolleite ratio in corrosion products were correlating. The principal protective effect of bivalent cations can be seen in the decrease of pH of the surface electrolyte, which was caused by hydrolysis of such cations and subsequent formation of simonkolleite that blocked the cathodic sites.

Leucite based ceramic materials are being a subject of an extensive scientific interest in recent years, especially in a field of dental prosthesis. Ceramic structures are used to replace missing teeth, tooth structure lost to disease or trauma, and unaesthetic, but otherwise healthy, tooth enamel [1]. The significant attributes of dental ceramics are its aesthetical (it can be coloured to closely resemble teeth it must replace) and chemical (stability toward oral flora and corrosive components of foods and saliva) qualities. The presence of leucite, exhibiting high values of a thermal expansion coefficient, in a porcelain matrix enables its fusion to metal reinforcement and so to achieve high mechanical strength. In addition in last few years it was hypothesized that leucite thanks to its phasetransition behaviour could potentially toughen leucite-glass (porcelain) systems and so lead to dental materials having high fracture toughness [2].

Lead iodide PbI2 is a promising material for X-ray and γ detectors. We report on the development and optimization of the method of direct synthesis for the preparation of PbI2 single crystals, purification by zone melting, and growth technique by using the Bridgman–Stockbarger method. We further report on addition of silver as admixture during synthesis in order to study its influence on properties of the prepared material, and on the possible formation of polytypes. The prepared lead iodide has been characterized by measurements of electrical resistivity and low-temperature photo-luminescence. X-ray diffraction has been used to monitor the crystallographic structure. It has been shown that Ag admixtures have changed resistivity of the PbI2 and has not influenced the basic polytype.

The aim of this work is to study the new method of direct synthesis of lead and iodine as the input material of PbI2. This method has not been studied for this material till now, and seems to be one of the new methods for preparation of the input material. The photoluminescence measurement and measurement of resistivity has been done and compared with the measurements done by precipitation and zone purification.

Lead iodide PbI2 is a promising material for X-ray and γ detector applications. Two methods of preparation of PbI2 are compared, precipitation and direct synthesis. The direct synthesis is a new method that brings good results. As an example of rare earth elements admixture Holmium has been used in order to investigate their influence on the properties of the resulting lead iodide crystals. Properties of the resulting material are characterized by performing electrical resistivity measurements and low temperature photoluminescence investigations. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)