Jordi Rius

Supramolecular self-assembled molecules as organic directing agent for synthesis of zeolites.

Solid materials with uniform micropores, such as zeolites, can act as selective catalysts and adsorbents for molecular mixtures by separating those molecules small enough to enter their pores while leaving the larger molecules behind. Zeolite A is a microporous material with a high void volume. Despite its widespread industrial use in, for example, molecular separations and in detergency, its capability as a petroleum-refining material is limited owing to its poor acid-catalytic activity and hydrothermal stability, and its low hydrophobicity. These characteristics are ultimately a consequence of the low framework Si/Al ratio (normally around one) and the resulting high cationic fraction within the pores and cavities. Researchers have modified the properties of type-A zeolites by increasing the Si/Al compositions up to a ratio of three. Here we describe the synthesis of zeolite A structures exhibiting high Si/Al ratios up to infinity (pure silica). We synthesize these materials, named ITQ-29, using a supramolecular organic structure-directing agent obtained by the self-assembly, through π–π type interactions, of two identical organic cationic moieties. The highly hydrophobic pure-silica zeolite A can be used for hydrocarbon separations that avoid oligomerization reactions, whereas materials with high Si/Al ratios give excellent shape-selective cracking additives for increasing propylene yield in fluid catalytic cracking operations. We have also extended the use of our supramolecular structure-directing agents to the synthesis of a range of other zeolites.

Neuron-Derived Orphan Receptor-1 (NOR-1) Modulates Vascular Smooth Muscle Cell Proliferation

Abstract— Vascular smooth muscle cells (VSMCs) migration and proliferation play a key role in the pathophysiology of cardiovascular disease. However, the transcription factors that regulate VSMC activation are not completely characterized. By a mRNA-differential display approach, we have identified neuron-derived orphan receptor-1 (NOR-1), a transcription factor within the NGFI-B subfamily of nuclear receptors, as a immediate-early gene in VSMCs. Two NOR-1 isoforms (&agr; and &bgr;) were identified and cloned from serum-induced porcine VSMC that shared high homology with the human isoforms. Northern blot analysis revealed a strong and transient (1 to 6 hours) upregulation of NOR-1 in both porcine and human coronary SMCs by growth factors (serum, platelet-derived growth factor-BB, and epidermal growth factor) and &agr;-thrombin but not by cytokines. NOR-1 upregulation is processed through G protein–coupled receptors and tyrosine kinase receptors, and involves Ca2+ mobilization, protein kinase C activation, and the mitogen-activated protein kinase pathway. This induction was closely dependent of the cAMP response elements present in NOR-1 promoter as transfection assays indicate. Human coronary atherosclerotic lesions overexpress NOR-1, and balloon angioplasty transiently induces NOR-1 in porcine coronary arteries with a pattern similar to that observed in VSMCs in culture. Antisense oligonucleotides against NOR-1 inhibited human coronary SMC proliferation (reduced de novo DNA synthesis, cell cycle progression, and VSMC wound repair) as efficiently as antisense against the protooncogene c-fos. These results show that NOR-1 modulates VSMC proliferation, and suggest that this transcription factor may play a role in both spontaneous and accelerated atherosclerosis.

Involvement of Neuron-Derived Orphan Receptor-1 (NOR-1) in LDL-induced Mitogenic Stimulus in Vascular Smooth Muscle Cells: Role of CREB

Objective—Low density lipoproteins (LDLs) modulate the expression of key genes involved in atherogenesis. Recently, we have shown that the transcription factor neuron-derived orphan receptor-1 (NOR-1) is involved in vascular smooth muscle cell (VSMC) proliferation. Our aim was to analyze whether NOR-1 is involved in LDL-induced mitogenic effects in VSMC. Methods and Results—LDL induced NOR-1 expression in a time- and dose-dependent manner. Antisense oligonucleotides against NOR-1 inhibit DNA synthesis induced by LDL in VSMCs as efficiently as antisense against the protooncogene c-fos. The upregulation of NOR-1 mRNA levels by LDL involves pertusis-sensitive G protein–coupled receptors, Ca2+ mobilization, protein kinases A (PKA) and C (PKC) activation, and mitogen-activated protein kinase pathways (MAPK) (p44/p42 and p38). LDL promotes cAMP response element binding protein (CREB) activation (phosphorylation in Ser133). In transfection assays a dominant-negative of CREB inhibits NOR-1 promoter activity, while mutation of specific (cAMP response element) CRE sites in the NOR-1 promoter abolishes LDL-induced NOR-1 promoter activity. Conclusions—In VSMCs, LDL-induced mitogenesis involves NOR-1 upregulation through a CREB-dependent mechanism. CREB could play a role in the modulation by LDL of key genes (containing CRE sites) involved in atherogenesis.

Copper complexes with a pyrazole derivative ligand. Crystal structure of tetrakis{[(3,5-bis(pyridin-2-yl)pyrazolate)-(aqua)copper(II) nitrate monohydrate}

Abstract Reaction of the pyrazole-derived ligand 3,5-bis(pyridin-2-yl)pyrazole (bpypz) with Cu(NO3)2, CuCl2 and CuBr2 yields polynuclear copper(II) compounds with remarkable structural and magnetic properties. The magnetic behaviour was studied by fitting the experimental data with a dimer and tetramer magnetic model. Strong antiferromagnetic exchange interactions were found in all cases. The molecular structure of the nitrate compound was solved by X-ray diffraction methods. The compound is tetranuclear, orthorhombic, space group Fddd, a = 18.572(4), b = 23.816(8), c = 27.337(9) A, V= 12092 A3, Z = 8.

The Hypoxia-Inducible Factor 1/NOR-1 Axis Regulates the Survival Response of Endothelial Cells to Hypoxia

ABSTRACT Hypoxia induces apoptosis but also triggers adaptive mechanisms to ensure cell survival. Here we show that the prosurvival effects of hypoxia-inducible factor 1 (HIF-1) in endothelial cells are mediated by neuron-derived orphan receptor 1 (NOR-1). The overexpression of NOR-1 decreased the rate of endothelial cells undergoing apoptosis in cultures exposed to hypoxia, while the inhibition of NOR-1 increased cell apoptosis. Hypoxia upregulated NOR-1 mRNA levels in a time- and dose-dependent manner. Blocking antibodies against VEGF or SU5614 (a VEGF receptor 2 inhibitor) did not prevent hypoxia-induced NOR-1 expression, suggesting that NOR-1 is not induced by the autocrine secretion of VEGF in response to hypoxia. The reduction of HIF-1α protein levels by small interfering RNAs, or by inhibitors of the phosphatidylinositol-3 kinase (PI3K)/Akt pathway or mTOR, significantly counteracted hypoxia-induced NOR-1 upregulation. Intracellular Ca2+ was involved in hypoxia-induced PI3K/Akt activation and in the downstream NOR-1 upregulation. A hypoxia response element mediated the transcriptional activation of NOR-1 induced by hypoxia as we show by transient transfection and chromatin immunoprecipitation assays. Finally, the attenuation of NOR-1 expression reduced both basal and hypoxia-induced cIAP2 (cellular inhibitor of apoptosis protein 2) mRNA levels, while NOR-1 overexpression upregulated cIAP2. Therefore, NOR-1 is a downstream effector of HIF-1 signaling involved in the survival response of endothelial cells to hypoxia.

New structures—new insights: Progress in structure analysis of nanoporous materials

In the recent past structure determination of microporous materials has experienced considerable developments in methodology. The FOCUS method: high resolution powder diffraction data used for direct method structure solution in combination with crystal chemistry based modelling. The models are retrieved from electron density maps calculated in direct method runs, energy minimized and checked through for realistic angles and distances values. The SUM-TF method: diffraction patterns at moderate resolution analysed with direct methods using a modified tangent formula which includes Patterson information for the structure solving. In this way the atomic resolution criterion for direct methods is bypassed. This overview gives a summary of the structures successfully solved using these new techniques.

Derivation of a new tangent formula from Patterson-function arguments

Most Patterson-search methods are based on functions measuring the coincidence of the observed Patterson function with the model Patterson function calculated as a function of some variables, e.g. the rotation angles in the case of the rotation function. In parallel with such methods, a new phase-refinement function based on the maximization of ZR(Φ) = ΣH(EH − 〈EH〉) GH(Φ) as a function of the collectivity Φ of phases of the reflections with large E values is presented, where EH − 〈EH〉 and GH(Φ) are the Fourier coefficients of two Patterson-type functions, the first with the origin peak removed and the second taking into account the atomicity condition. It will be shown how ZR(Φ) can be maximized by a new tangent formula actively using the small E values and not possessing any weighting factor. The utility of this formula is illustrated on the basis of two representative test examples.

Quantitative X-ray diffraction phase analysis of coarse airborne particulate collected by cascade impactor sampling

Mineralogical composition of Castellon (Spanish Mediterranean coast) atmospheric aerosol was studied by X-ray diffraction by sampling with a cascade impactor without filters. Quantitative phase analysis of natural phases present in the atmospheric coarse aerosol was performed using a modified version of the computer program MENGE, that uses the standardless X-ray method developed by Rius for the quantitative analysis of multiphase mixtures, adapted for PC running. Presence of quartz, calcite and gypsum was identified in the atmospheric aerosol and we have quantified their amounts using the standardless method.

Macrocycles incorporating closo- and nido-carbaborane cages: molecular structure of 1,2-(3′-oxapentane-1′,5′-dithiolato-SS′)-1′,2′-dicarba-closo-dodecaborane

Reaction of 1,2-dimercapto-1,2-dicarba-closo-dodecaborane under basic conditions with appropriate dihalogenated organic compounds results in the formation of macrocycles incorporating 7,8-dicarbaundecaborate or 1,2-dicarba-closo-dodecaborane units. Polymers are obviated by using high dilution. The crystal structure of 1,2-(3′-oxapentane-1′,5′-dithiolato-SS′)-1′,2′-dicarba-closo-dodecaborane has been determined. It crystallizes in space group P21/a with four formula units in a cell of dimensions a= 11.708(2), b= 10.209(3), c= 12.613(3)A, and β= 109.04(2)°.

Solid-state transformation of the MOF [Ni2(bipy)1.5(PDC)2(H2O)2]·3.5H2O

The combination of non-centrosymmetric ligands and dipyridyl spacers produces a MOF that potentially can be porous with formula [Ni2(bipy)1.5(PDC)2(H2O)2]·3.5H2O (bipy = 4,4′-bipyridine and PDC = pyridine-2,5-dicarboxylate). Dehydration of this compound results in a new MOF in which the formation of additional bonds between the carboxylate groups of PDC and the metal ion has occurred. This solid-state transformation takes place with no significant changes in the coordination sphere of the metal ion, which is unusual for coordination polymers. Both compounds exhibit the same unprecedented topology where the connectivity between nodes is remarkably high.