15‐Hydroperoxy‐PGE2: Intermediate in Mammalian and Algal Prostaglandin Biosynthesis

Arachidonic‐acid‐derived prostaglandins (PGs), specifically PGE₂, play a central role in inflammation and numerous immunological reactions. The enzymes of PGE₂ biosynthesis are important pharmacological targets for anti‐inflammatory drugs. Besides mammals, certain edible marine algae possess a comprehensive repertoire of bioactive arachidonic‐acid‐derived oxylipins including PGs that may account for food poisoning. Described here is the analysis of PGE₂ biosynthesis in the red macroalga Gracilaria vermiculophylla that led to the identification of 15‐hydroperoxy‐PGE₂, a novel precursor of PGE₂ and 15‐keto‐PGE₂. Interestingly, this novel precursor is also produced in human macrophages where it represents a key metabolite in an alternative biosynthetic PGE₂ pathway in addition to the well‐established arachidonic acid‐PGG₂‐PGH₂‐PGE₂ route. This alternative pathway of mammalian PGE₂ biosynthesis may open novel opportunities to intervene with inflammation‐related diseases.     

N.m.r. spectra of prostaglandin metabolites and precursors and of related pyrazoline adducts

The ¹³C n.m.r. spectra of the major human urinary metabolite of prostaglandin PGE₂ and PGE₁ are discussed together with some unsaturated precursors. Δ-2-Pyrazolines, formed by addition of diazomethane to the 11-oxo dienediones in this series, were identified by ¹³C and ¹H n.m.r. and by other physical methods.     

Study of the white-rot fungal degradation of selected phthalocyanine dyes by capillary electrophoresis and liquid chromatography

The phthalocyanine dyes, Remazol Turquoise Blue G133, Everzol Turquoise Blue and Heligon Blue S4 are found to be biosorbed by Phanerochaete chrysosporium (white-rot fungi) and also metabolised by its ligninolytic extracellular enzymes resulting in dye decolourisation, formation of free copper ions and organic metabolites with ultimate extensive phthalocyanine ring breakdown. It is believed that the ligninolytic extracellular enzyme laccase is involved in the early production of a metabolite M₈ which involves break-up of the conjugated phthalocyanine ring structure but which retains multi-negative charge. Another ligninolytic extracellular enzyme, manganese peroxidase, is believed to be involved in the release of Cu²⁺ from the phthalocyanine structure to give a non-copper-containing phthalocyanine metabolite M₁ with a slightly longer migration time than the parent dye and absorption at 666 nm. The phthalocyanine ring structure is also broken up by metabolic processes that involve desulphonation and oxidation to give phthalimide (M₃) and an unidentified electroactive metabolite M₂. Other minor, unidentified metabolites are observed using capillary electrophoresis and liquid chromatography.     

Malva sylvestris L. extract suppresses desferrioxamine‐induced PGE2 and PGD2 release in differentiated U937 cells: the development and validation of an LC‐MS/MS method for prostaglandin quantification

Malva sylvestris is a species used worldwide as an alternative to anti‐inflammatory therapies; however, its mechanism of action remains unknown. In this paper, the anti‐inflammatory effects of M. sylvestris alcoholic extracts were evaluated by measuring the pro‐inflammatory mediators PGE₂ and PGD₂ in desferrioxamine‐stimulated phorbol 12‐myristate 13‐acetate‐differentiated U937 cells. An HPLC‐DAD fingerprint of the M. sylvestris extract was performed and caffeic acid, ferulic acid and scopoletin were identified and quantified. An HPLC‐MS/MS method was developed and validated to separate and measure the prostaglandins. The lower limits of detection (~0.5 ng/mL for PGE₂ and PGD₂) and quantification (1.0 ng/mL for PGE₂ and PGD₂) indicated that the method is highly sensitive. The calibration curves showed excellent coefficients of correlation (r > 0.99) over the range of 1.0–500.0 ng/mL, and at different levels, the accuracy ranged from 96.4 to 106.4% with an RSD < 10.0% for the precision study. This method was successfully applied using U937‐d cells. A significant dose‐dependent reduction of PGE₂ and PGD₂ levels occurred using 10 µg/mL (10.74 ± 2.86 and 9.60 ± 6.89%) and 50 µg/mL of extract (48.37 ± 3.24 and 53.06 ± 6.15%), suggesting that the anti‐inflammatory mechanisms evoked by M. sylvestris may be related to modulation of these mediators. Copyright © 2014 John Wiley & Sons, Ltd.     

Influence of Molar Mass Distribution on the Compatibility of Polymers

Abstract

Phase equilibria were calculated by means of a new method (direct minimization of the Gibbs energy of mixing) for polymer blends consisting of monodisperse polymer A and polydisperse polymer B. The results obtained for a Schulz-Flory distribution of B (molecular nonuniformity U = (M _w/M _n) ?1 = 1 and 100 components of model B) agree quantitatively with that of computations on the basis of continuous thermodynamics. The influence of U _B on the miscibility of A and B in 1:1 mixtures was studied for constant M _w of B, quantifying the incompatibility of the polymers by the length of the tie lines. The outcome of these calculations demonstrates that the typical effect of an augmentation of U _B (keeping M _w and the overall composition constant) consists in an enlargement of the mutual solubility of A and B. However, for an almost compatible pair of polymers (i.e., interaction parameters g are only slightly larger than the critical values for U _B = 0), this statement remains true only in the case of sufficiently small U _B. In order to gain some understanding of these findings, calculations were also performed for ternary systems (A and two species B). They demonstrate that it is the distance of the overall composition in the Gibbs phase triangle to the critical line (connecting the critical points for different U _B) which governs the changes in compatibility. Normally the critical point comes closer to the overall composition as U _B is raised, except for low g values where the critical point — after an initial approach — drifts apart as U _B becomes larger.     

Lattice embedding and equilibrium geometry of metal-halogen chains in the two-band extended Hubbard model

Two-band extended Hubbard model studies show that the shift in optical gap of the metal-halogen (MX) chain upon embedding in a crystalline environment depends upon alternation in the site-diagonal electron-lattice interaction parameter (ε_M) and the strength of electron-electron interactions at the metal site (U_M). The equilibrium geometry studies on isolated chains show that the MX chains tend to distort for alternating ε_M and smallU _M values. Communication No. 935 from SSCU     

Relations structurales entre U3O8 et quelques fluorures mixtes de formules M2M′3F11, MM′2F7 et MM′3F10

U₃O₈ oxide, as well as M₂M′₃F₁₁, MM′₂F₇ and MM′₃F₁₀ fluorides, with M = Rb, Tl, Cs, NH₄ and M′ = In, Lu, Yb, Tm, is described as the regular repetition according to the … A-A-A … sequence of identical and parallel sheets of edge-and corner-sharing M′F₇ or UO₇ pentagonal bipyramids and M′F₆ octahedra. M′ and U atoms are systematically located at the lattice points of a pseudohexagonal network, but in the fluorides some of these lattice points are vacant, producing hexagonal tunnels in which M atoms are located. It is shown that in the two kinds of compounds the same linear chains and M′₃X₁₇ groups of pentagonal bipyramids are present, and that the transformation of the U₃O₈ structure into the fluorides can be achieved by an ordered substitution of some linear … UOUO … chains by … M-M-M … chains. All these structures can be described with the same structural model based on the chemical twinning principle.     

Hardness evaluation of cured urea–formaldehyde resins with different formaldehyde/urea mole ratios using nanoindentation method

To understand the influence of formaldehyde/urea (F/U) mole ratio on the properties of urea–formaldehyde (UF) resins, this study investigated hardness of cured UF resins with different F/U mole ratios using a nanoindentation method. The traditional Brinell hardness (H_B) method was also used for comparison. The H_B of cured UF resin films with different F/U mole ratios was determined after exposing the films to different post-curing temperatures. The nanoindentation method was employed for these films to measure Meyer hardness (H_M) and reduced modulus (E_r) which have been used to calculate the elastic modulus (E_s) of cured UF resins. As the F/U mole ratio decreased, the H_B decreased continuously, indicating a less rigid network structure in low F/U mole ratio UF resins. The higher the post-curing temperature, the greater the value of H_B. The H_M value also showed a similar trend as a function of F/U mole ratio. However, the E_r and E_s did not show a consistent trend as exhibited by H_M and H_B. Both H_M and E_r showed much greater variation in the coefficient of variation (COV) at lower F/U mole ratios 1.0 and 1.2, indicating a more heterogeneous composition of these resins. Linear relationships between H_M and E_r indicate that heterogeneity of the surface composition of samples contributes greatly to variations in the measured values. This variability is discussed in terms of crystal structures present in the cured UF resins of low F/U mole ratios.     

Reduction of the photoexcited uranyl ion by water

Photooxidation of water by the uranyl ion was studied. Solutions of uranyl in 0.01–4.0M H₂SO₄, HClO₄, or 0.1–1.0M Na₂SO₄ and NaClO₄ containing “lacunary” heteropolytungstate (HPT) K₁₀P₂W₁₇O₆₁ or K₈SiW₁₁O₃₉ were irradiated with a nitrogen laser, a mercury or xenon lamp, or visible light. Spectrophotometric analysis showed that the irradiation results in the accumulation of U^IV. Simultaneously the formation of H₂O₂ proceeds. The quantum yield Φ of the reaction increases as the concentration of the acid or salt increases. For aerated solutions of 1M H₂SO₄ or 1M HClO₄, irradiation by light with λ=337.1 Φ is close to (1.5–2)·10⁻³. The irradiation of solutions with pH −4 for many days leads to an almost quantitative transformation of UO₂ ²⁺ into U^IV. When the irradiation was carried out in the absence of HPA, U^IV was not detected, although hydrogen peroxide was observed in the solution. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya. No. 2, pp. 282–287, February, 2000.     

Release of Inflammatory Mediators (PGE2, IL-6) by Fenofibric Acid-Photosensitized Human Keratinocytes and Fibroblasts

Ultraviolet-A radiation has weak effects on the release of inflammatory mediators by skin cells due to the poor overlap between UVA wavelengths and the absorption spectra of the relevant chromophores of key biomole-cules. However, this situation could be very different in the presence of a photosensitizing drug. To investigate this issue, we have irradiated human skin cells (keratinocytes and fibroblasts) in the presence of fenofibric acid (the active phototoxic metabolite of fenofibrate). The results of this research show a dual effect on the production/release of inflammatory mediators: the synthesis of the proinflammatory cytokine interleukin-6 becomes strongly inhibited at photosensitizer concentrations that clearly stimulate the production of prostaglandins (PGE₂) by skin cells. We have found evidences showing that the de novo synthesis of cytokines is inhibited in photosensitized cells due to the fact that cellular mRNA is degraded. Interestingly, when the medium taken from irradiated cultures is added to nonexposed cells, a significant stimulation of cytokine synthesis is observed that can be inhibited by anti-PGE₂ antibodies. These observations may be relevant in vivo, where prostaglandins released by photosensitized skin cells could stimulate cytokine synthesis by underlying, nonirradiated cells.     

Thermodynamics and phase relationships of the ternary lanthanum-uranium-oxygen system

In the selected regions La:(La + U) = 0.05 and O:(La + U) = 2.00 of the ternary system lanthanum-uranium-oxygen emf measurements on solid state galvanic cells, coulometric titrations, and X-ray diffraction techniques were used to obtain phase boundaries and thermodynamic data in the temperature range from 600 to 1000°C. For the first time order disorder transformations of La_1−yU_yO_2+x up to 15 mole% lanthanum are reported. The transformation temperature is 1415°K for UO_2.23; 1397°K for La_0.05U_0.95O_2.23, and 1449°K for La_0.15U_0.85O_2.23. The vibrational entropy component of excess oxygen in M_1−yU_yO_2+x is estimated.     

Synthesis,structures, IR spectra,and thermal characteristics of compounds of general formula Ba(M<Stack><Subscript>2/3</Subscript><Superscript>III</Superscript></Stack>U<Subscript>1/3</Subscript>)O<Subscript>3</Subscript> (M<Superscript>III</Superscript> = Sc,Y, In,Nd-Lu)

Compounds with the composition Ba(M _2/3 ^III U_1/3)O₃ (M^III = Sc, Y, In, Nd-Lu) were synthesized by high-temperature solid-state reactions. The structures of the compounds were studied by X-ray diffraction analysis, including the high-temperature method, and IR spectroscopy.     

The evaluation of matrix elements for non-canonical Weyl tableau basis states adapted toU(n 1+n 2)⊃U(n 1)×U(n 2)

Summary This is the first paper of a series of two, which enables the evaluation ofU(n) generator matrix elements in the non-canonical Weyl tableau basis adapted to subgroupU(n ₁)×U(n ₂). In this paper the explicit closed formulae for subduction coefficients are presented. These formulae will become useful through an inductive method to be presented in the second paper.     

On unicyclic conjugated molecules with minimal energies

The energy of a graph is defined as the sum of the absolute values of all the eigenvalues of the graph. Let U(k) be the set of all unicyclic graphs with a perfect matching. Let C _g(G) be the unique cycle of G with length g(G), and M(G) be a perfect matching of G. Let U ⁰(k) be the subset of U(k) such that g(G)≡ 0 (mod 4), there are just g/2 independence edges of M(G) in C _g(G) and there are some edges of E(G)\ M(G) in G\ C _g(G) for any G∈U ⁰(k). In this paper, we discuss the graphs with minimal and second minimal energies in U ^*(k) = U(k)\ U ⁰(k), the graph with minimal energy in U ⁰(k), and propose a conjecture on the graph with minimal energy in U(k).      

Analysis of a failure of the CC2 coupled-cluster method for bond lengths of SnO and PbO

CC2 model is found to overestimate bond lengths of SnO and PbO by about 0.25 Å, while both second-order Møller–Plesset perturbation theory and coupled-cluster singles and doubles give reasonable results. Previously, analysis shows that the [[U, T ₁], T ₁] term in the doubles equation of CC2 is the origin of failure for CC2 and some truncated CC models have been suggested to achieve reasonable result for ozone, where CC2 is unable to obtain a stable structure. However, these remedies are unable to afford reasonable bond lengths of SnO and PbO. Based on a term-wise analysis, our results indicate that the [U, T ₁] term results in failure of CC2. CC2 model by removing this term will provide results that agree well with those of MP2. Furthermore, the [[U, T ₂], T ₁] term absent in the CC2 while present in doubles equation of CCSD can balance this [U, T ₁] term and CC2 model augmented with this term is able to afford reasonable results for PbO, SnO and ozone.     

Synthesis of two metabolites of 2,4-diamino-5(3,4,5-trimethoxybenzyl)-pyrimidines (Trimethoprim)

The synthesis of two metabolites M₃ and M₄ of 2,4-diamino-5-(3, 4, 5-trimethoxybenzyl)-pyrimidine (trimethoprim, 1 ) is reported. M₃ (trimethoprim 1-oxide) as well as the isomeric 3-oxide were prepared by oxidation of 1 with m-chloroperbenzoic acid. The structure of M₃ was finally established by x-ra analysis [4]. The metabolite M₄ [2, 4-diamino-5-(3-hydroxy-4, 5-dimethoxy-benzyl)-pyrimidine] was prepared by condensation of 3-benzyloxy-4, 5-dimethoxybenzaldehyde ( 2 ) with 3-methoxypropionitrile ( 3 ) and guanidine followed by hydrogenolysis of the intermediate 3-benzyloxy compound 4 .     

Fractionation of Cellulose

Cellulose samples with molecular weight distributions that are considerably narrower than those of the natural products can be obtained by at least three fundamentally different routes. (i) Synthesis of easily soluble derivatives, fractionation by means of well-established methods and subsequent regeneration, (ii) selective extraction of short chains from activated cellulose, using solvents of suitable marginal quality, and (iii) partition of the homologs between two coexisting phases formed by the demixing of homogeneous solutions. All three methods can be applied successfully. However, the efforts in terms of labor and required solvent differ considerably. Most of the experiments were performed with the following three cellulose samples: Avicel (M _w = 30 kg mol^–1, U = (M _w/M _n)–1 = 2.0), Solucell (M _w = 230 kg mol^–1, U = 1.8), and Stockstadt (M _w = 320 kg mol^–1, U = 5.7). Options (ii) and (iii) emerged most promising for large scale fractionation. The mixed solvent consisting of DMAc and LiCl turned out to be particularly versatile in both cases. In the pure state it can be used for incremental extraction (yielding quick access to orienting information on the width of the molecular weight distribution) as well as for one-step extraction. In combination with suitable precipitants (like acetone) it enables the realization of the coexistence of two liquid phases required with route (iii). One obstacle for fractionation that all methods share is the high viscosity of cellulose solutions. With the last method it is possible to mitigate this limitation considerably by the use of spinning nozzles for the mixing of feed and extracting agent.     

Probe—detektor-anordnungen zur Kernstrahlungsmessung für Analytische Zwecke

The “analytical power” of detection systems is investigated, considering typical arrangements in analytical terms. From N atoms of interest in a sample Z counts are drawn: Z=R N (R registration yield). Crude data ZM contain also background U generated by interferences: ZM=Z+U. Identification and separation of Z is accompanied by errors ~σ_MU^1/2 due to imperfect distinguishability and to statistical error (σ_M model inherent factor). With “selectivity”=σ_M ^- (R/R_interference)^1/2 the figure of merit is G=selectivity efficiency/interference)^1/2. Sample background dominating, “interference” or both “interference” and “efficiency” have to be cancelled. Present semiconductor spectrometry of low energy γ-quanta and of large rates is not very far from its limits. Further progress will be obtained by enhancement of high energy efficiency and reduction of natural background.      

The Synthesis and Crystal Structure of Doped Uranium Brannerite Phases U1−xMxTi2O6 (M=Ca, La, and Gd)

Doped uranium brannerite phases (U_1−xM_xTi₂O₆; M=Ca²⁺, La³⁺ and Gd³⁺; x<0.5) were synthesized at 1400°C; the range of solid solution was found to vary depending on whether sintering took place in argon or air. Powder X-ray diffraction revealed that these phases crystallized to form monoclinic (C2/m) structures. In particular, the crystal structures of U_0.74Ca_0.26 Ti₂O₆ (1) (a=9.8008(2); b=3.7276(1); c=6.8745(1); β=118.38(1); V=220.97(1); Z=2; R_P=7.3%; R_B=4.6%) and U_0.55La_0.45Ti₂O₆ (2) (a=9.8002(7); b=3.7510(3); c=6.9990(5); β=118.37(4); V=226.40(3); Z=2; R_P=4.5%; R_B=2.9%) were refined from powder neutron diffraction data, revealing planes of corner and edge-sharing TiO₆ octahedra separated by 8-fold coordinate U/M atoms. The oxygen sites within these structures were found to be fully occupied, confirming that the doping of lower valence M atoms occurs in conjunction with the oxidation of U(IV) to U(V).     

Lower oxidation states of lanthanides and actinides. Prospects of their use in analytical practice

Physico-chemical characteristics of Ln²⁺ and An²⁺ such as standard oxidation potentials E_M ³⁺M²⁺, hydration energies, ionic radii were obtained by the cocrystallization method. A number of energy parameters for Ln²⁺ and U³⁺ were obtained by optical spectroscopy on the basis of fd-spectra in such solvents as H₂O, C₂H₅OH, HMPA, THP and others. A new rapid method has been developed to extract higher actinides and separate them from similar elements by cocrystallization with NaCl from aqueous ethanolic solutions.