Effect of Water on the Partial Oxidation of Propane to Acrylic and Acetic Acids on Mo-V-Sb-Nb Mixed Oxides

It is shown that the major effect of water in the oxidation of propane to acrylic and acetic acids on Mo₁V_0.3Sb_0.25Nb_0.08O _n catalysts is to stabilise the active sites and increase the rates of formation of both acids. The usual effect of favoring desorption of the products is considered to be secondary.     

Effect of polymer structure on the molecular dynamics and thermal behavior of poly(allyl acetoacetate) and copolymers

In this paper, dielectric and calorimetric studies of the small-molecule glass former allyl acetoacetate monomers as well as its newly synthetized homopolymer and copolymers with different styrene composition were performed in both the liquid and glassy states. The molecular dynamics studies by the broadband dielectric spectroscopy and the stochastic temperature modulated differential scanning calorimetry enabled us to explore relaxation processes of examined materials in the wide frequency range. We found that the copolymers reveal two co-existing glass transitions characterized by the glass transition temperatures, which are very close to those of the corresponding homopolymers. These results suggest that the copolymers exhibited some sequences of acetoacetate units with a microphase-separated morphology in agreement with the value of reactivity ratio previously determined. We investigated effects of copolymerization compositions on the glass transition temperature, the isobaric fragility index, the dielectric and calorimetric intensity, and the dynamic heterogeneity on the glass transitions of the materials.     

Cleaner production financing: possibilities and barriers

There are several players who could facilitate the promotion of cleaner production (CP) by establishing an effective financing mechanism; for instance, government, international assistance bodies, banks and other financing organizations. In a few developing countries in South East Africa and Latin America and in Vietnam several international organizations, development banks and donors have initiated and implemented projects to facilitate the introduction of CP investments. Most projects have been in the form of technical assistance grants and training to industries and/or loans at below market rates from dedicated trust funds. Yet the present level of lending through such projects is far from sufficient to trigger widespread adoption of CP. Therefore, experts from The Institute of Environmental Engineering, Lithuania performed an investigation to create a CP development scheme for developing countries.     

Tetrapyrazinoporphyrazines with different number of peripheral pyridyl rings: Synthesis,photophysical and photochemical properties

Zinc tetrapyrazinoporphyrazines comprising different numbers of pyridin-2-yl and tert-butylsulfanyl substituents were prepared by the statistical condensation of two precursors – 5,6-bis(tert-butylsulfanyl)pyrazine-2,3-dicarbonitrile (A) and 5,6-dipyridin-2-yl-pyrazine-2,3-dicarbonitrile (B). The ensuing zinc tetrapyrazinoporphyrazines were chromatographically separated on silica column and characterized. Adjacent (AABB) and opposite (ABAB) isomers were not separated. The prepared zinc tetrapyrazinoporphyrazines did not differ in their Q-band position but the B-band position was shifted hypsochromically for compounds bearing more pyridyl units; in addition, a weak band at 450–520 nm decreased with increasing number of pyridyl substituents. Singlet oxygen quantum yields (Φ_Δ in the range 0.69–0.53) decreased with increasing number of pyridyl units on the macrocyclic core, while fluorescence quantum yields showed the reverse tendency (Φ_F in the range 0.22–0.26).     

Mössbauer spectroscopy study of iron complexes in a poly(methacrylic acid) hydrogel matrix

Using Mössbauer spectroscopy, we have studied iron complexes resulting from the interaction of aqueous iron salt solutions with poly(methacrylic acid) (PMAA) gel. In these complexes, the di- and trivalent Fe ions are linked to the PMAA through the COO^? functional group. From the observed dynamics of the variation in the intensities of the di- and trivalent iron in the Mössbauer spectra of the gels with incubation time and iron concentration in solution, we have inferred a model for the incorporation of Fe ions into a gel matrix.     

Homozygous cystathionine beta-synthase deficiency, combined with factor V Leiden or thermolabile methylenetetrahydrofolate reductase in the risk of venous thrombosis

Severe hyperhomocysteinemia in its most frequent form, is caused by a homozygous enzymatic deficiency of cystathionine beta-synthase (CBS). A major complication in CBS deficiency is deep venous thrombosis or pulmonary embolism. A recent report by Mandel et al (N Engl J Med 334:763, 1996) postulated factor V Leiden (FVL) to be an absolute prerequisite for the development of thromboembolism in patients with severe hyperhomocysteinemia. We studied 24 patients with homocystinuria caused by homozygous CBS deficiency from 18 unrelated kindreds for FVL and for the 677C-->T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene and investigated their possible interaction in the risk of venous thrombosis. Thrombotic complications were diagnosed in six patients, of whom only one was a carrier of FVL. On the contrary, thermolabile MTHFR caused by the 677C-->T mutation, was frequently observed among homocystinuria patients, especially among those with thromboembolic complications: three of six homocystinuria patients who had suffered from a thromboembolic event had thermolabile MTHFR. These data indicate that FVL is not an absolute prerequisite and probably not even a major determinant of venous thrombosis in homocystinuria, but, interestingly, thermolabile MTHFR may constitute a significant risk factor for thromboembolic complications in this inborn error of methionine metabolism.     

Highly selective sigma receptor ligands elevate inositol 1,4,5-trisphosphate production in rat cardiac myocytes

Exposure of cardiac myocytes from adult rat ventricles to the highly selective, high affinity sigma receptor ligands 1S,2 R-cis-N-[2-(3,4-dichlorophenyl)ethyl]-N-methyl-2-(1-pyrrolidinyl)-cycloh exylamine (BD-737) (0.1-100 nM) and N-[2-(3,4-dichlorophenyl)ethyl]-N,N',N'-trimethylethylenediamine (BD-1047) (0.01-10 nM), caused potentiation of electrically-evoked amplitudes of contraction and Ca2+ transients, while exposure to 100 nM BD-1047 caused attenuation of these amplitudes. In addition, BD-737 (1-100 nM) and BD-1047 (10-100 nM) caused an increase in the incidence of spontaneous twitches. These effects were inhibited when the incubation with BD-737 was done in the presence of the phospholipase C inhibitor, neomycin, or after pre-incubation with thapsigargin or caffeine which deplete the sarcoplasmic reticulum Ca2+ stores. Inositol 1,4,5-trisphosphate (IP3) production in cardiac myocytes was determined by the IP3 binding protein assay. Both substances caused an increase in the intracellular concentration of IP3. BD-737 caused a rapid transient increase to 3.2-fold in 1 min and stabilization at 2.1-fold of control thereafter. BD-1047 caused a gradual increase reaching 4.4-fold after 5 min. The results suggest that the effects of these sigma receptor ligands on contractility and spontaneous contractions are mediated by activation of phospholipase C and elevation of intracellular IP3 level.     

Ordinary Gasoline Emissions Induce a Toxic Response in Bronchial Cells Grown at Air-Liquid Interface

Gasoline engine emissions have been classified as possibly carcinogenic to humans and represent a significant health risk. In this study, we used MucilAir™, a three-dimensional (3D) model of the human airway, and BEAS-2B, cells originating from the human bronchial epithelium, grown at the air-liquid interface to assess the toxicity of ordinary gasoline exhaust produced by a direct injection spark ignition engine. The transepithelial electrical resistance (TEER), production of mucin, and lactate dehydrogenase (LDH) and adenylate kinase (AK) activities were analyzed after one day and five days of exposure. The induction of double-stranded DNA breaks was measured by the detection of histone H2AX phosphorylation. Next-generation sequencing was used to analyze the modulation of expression of the relevant 370 genes. The exposure to gasoline emissions affected the integrity, as well as LDH and AK leakage in the 3D model, particularly after longer exposure periods. Mucin production was mostly decreased with the exception of longer BEAS-2B treatment, for which a significant increase was detected. DNA damage was detected after five days of exposure in the 3D model, but not in BEAS-2B cells. The expression of CYP1A1 and GSTA3 was modulated in MucilAir™ tissues after 5 days of treatment. In BEAS-2B cells, the expression of 39 mRNAs was affected after short exposure, most of them were upregulated. The five days of exposure modulated the expression of 11 genes in this cell line. In conclusion, the ordinary gasoline emissions induced a toxic response in MucilAir™. In BEAS-2B cells, the biological response was less pronounced, mostly limited to gene expression changes.     

The formation of Fe–Ga–In nanocomposite particles using mechanochemical interaction of Fe with the Ga–In eutectic

Mechanochemical interaction of Fe powder with the liquid Ga–In eutectic in the Fe-rich concentration corner of the Fe–Ga–In phase diagram was studied and compared with binary Fe–Ga and Fe–In specimens. Slow formation of diluted solid solutions in the Fe–In system was confirmed. In the Fe–Ga system, the dominant concentrated A2 solid solution is formed with H_eff?=?236 kOe, accompanied by ordered D0₃ and L1₂ phases. The Fe–Ga–In system features a stationary equilibrium between the concentrated A2 phase and D0₃ in the iron matrix.