2-substituted benzofuran fragment ion formation in the electron ionization mass spectra of 6-alkyl- and 6-aryldibenzo(d,f)(1,3)dioxepine derivatives. 1. Spirocyclization of the molecular ions in the gas phase

The formation of 2-substituted benzo[b]furan ions in the electron ionization (EI) mass spectra of a series of 6-alkyl- and 6-aryldibenzo(d,f)(1,3)dioxepines has been studied by means of exact mass measurements and multiple-stage mass spectrometry conditions using an ion trap mass spectrometer. The proposed mechanism of formation of benzo[b]furan ions requires the formation of a spirocyclic cyclohexadienone system, which undergoes elimination of a cyclopentadienone molecule. A parallel with the chemical conversion of arylmethyl-substituted dibenzo(d,f)(1,3)dioxepines into an analogous spirocyclic system was also underlined.     

Purification and Applications of a Lectin from the Mushroom Gymnopilus spectabilis

A lectin was isolated from fruiting bodies of the mushroom Gymnopilus spectabilis (GSL) by ionic exchange chromatography. The lectin agglutinates mouse red cells exhibiting broad specificity towards several monosaccharides including the N-acetylneuraminic acid. Agglutination was also inhibited by the glycoproteins: fetuin, lactoferrin, and recombinant erythropoietin. GSL is a glycoprotein possessing 16 % of carbohydrates; the SDS-PAGE showed two bands with molecular mass of 52.1 and 64.4 kDa. Isoelectric focusing displayed microheterogeneity, with two bands at pIs 5.1 and 5.3. The lectin was stable between pH 2 and pH 8 while at pH 10, the agglutination decayed to 50 % of initial activity. Incubation at 40 and 80 °C led to 50 and 100 % loss in activity of the lectin, respectively. Synthesized GSL-Sepharose interacts with serum pregnant mare gonadotropin, and at least two subpopulations of this glycoprotein were separated. There was no interaction between transferrin and soluble GSL while a partial recognition was achieved with GSL-Sepharose. The terminal sialic acid seems to play an active role in modifying the interaction with GSL, depending if the lectin is in a soluble or immobilized form. The purified lectin inhibited in vitro the growth of Staphylococcus aureus and Aspergillus niger.     

Controlled coherent dynamics of [VO(TPP)], a prototype molecular nuclear qudit with an electronic ancilla

We show that [VO(TPP)] (vanadyl tetraphenylporphyrinate) is a promising system to implement quantum computation algorithms based on encoding information in multi-level (qudit) units. Indeed, it embeds a nuclear spin 7/2 coupled to an electronic spin 1/2 by hyperfine interaction. This qubit–qudit unit can be exploited to implement quantum error correction and quantum simulation algorithms. Through a combined theoretical and broadband nuclear magnetic resonance study, we demonstrate that the elementary operations of such algorithms can be efficiently implemented on the nuclear spin qudit. Manipulation of the nuclear qudit can be achieved by resonant radio-frequency pulses, thanks to the remarkably long coherence times and the effective quadrupolar coupling induced by the strong hyperfine interaction. This approach may open new perspectives for developing new molecular qubit–qudit systems.

By a combined theoretical and broadband nuclear magnetic resonance study, we show that [VOTPP] is a coupled electronic qubit-nuclear qudit system suitable to implement qudit-based quantum error correction and quantum simulation algorithms.     

Effects of localised and global convection on thermal explosion in a parallel-plate geometry

During an exothermic reaction in a fluid, convection may ensue on a local scale and then develop to the scale of the entire vessel. In this work, we study the effects of both localised and global convection on thermal explosions occurring between parallel plates. Analytical relations are derived for the various transitions in regimes of convective and thermal behaviours. We show that these relations agree well with previous numerical work and with new simulations in the present investigation. We also determine analytically the time for onset of convection, as well as the temperature increase at that time, for stable and explosive systems. The effects of the Prandtl number of the fluid on the transitions between regimes are noted.     

Isomorfismi tra le strutture subnormali dei gruppi

Summary In this paper order-isomorphisms between subnormal structures of subsoluble groups are considered, and the images of generalized nilpotent groups in such isomorphisms are studied. A result of Pazderski about the Fitting subgroup of finite soluble groups is also extended to the upper Baer series of subsoluble groups, and an extension to infinite groups of a theorem of Heineken about isomorphisms between lattices of subnormal subgroups of finite groups is given.

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Lavoro eseguito nell'ambito del G.N.S.A.G.A. del C.N.R.     

Some functional inequalities for complete elliptic integrals

We establish some monotonicity results and inequalities involving elliptic integrals of the first and the second kind. Work sponsored by the Ministero dell’Università e della Ricerca Scientifica e Tecnologica of Italy.     

Comparison of microbial activity in some Brazilian soils by microcalorimetric and respirometric methods

The microbial activity in a Rhodic eutrudox (R), a Typic eutrudox (V) and a Quartzipsamment (Q) was monitored by respirometric and calorimetric methods. CO₂ evolution was monitored for 98 days by titrimetry and conductimetry for control amended samples (A) with 25% of cattle manure (E), municipal refuse compost (L), earthworm casts (H) or 1.25 kg ha⁻¹ of trifluralin (T). Average values of all treatments through respiration at the end of the incubation period were 5.24±0.34, 6.13±0.31 and 6.50±0.33, in mg CO₂ g⁻¹ soil, for R, V and Q, respectively, by titrimetry and 8.89±0.44, 10.41±0.54 and 10.41±0.52, in mg CO₂ g⁻¹ soil, for R, V and Q, respectively, for conductimetry. Excellent correlation (r=1.00) between titrimetry and conductimetry was observed. The decreasing order for respiration was E, H, L and T. After each incubation time, the conductimetric values were higher than those for titrimetry, for all treatments of these Brazilian soils. Average values of the exothermic thermal effect were: 0.58±0.02, 0.60±0.02 and 0.67±0.01 kJ g⁻¹ soil, for R, V and Q, respectively, for 103 days. A significant correlation coefficient of 0.91 and P<0.0001 between calorimetric and respirometric values over 98 days was observed. Based on the obtained calorimetric results, it can be proposed that this technique should be as a useful analytical method for determining the microbial activity in soils.     

On automorphisms fixing non-normal subgroups of groups

This work was carried out when the last named author visited the Department of Mathematics of the University of Napoli Federico II in March 1994. He is very grateful for the hospitality he enjoyed and for the support by the C.N.R.     

Novel Bis- and Mono-Pyrrolo[2,3-d]pyrimidine and Purine Derivatives: Synthesis,Computational Analysis and Antiproliferative Evaluation

Novel symmetrical bis-pyrrolo[2,3-d]pyrimidines and bis-purines and their monomers were synthesized and evaluated for their antiproliferative activity in human lung adenocarcinoma (A549), cervical carcinoma (HeLa), ductal pancreatic adenocarcinoma (CFPAC-1) and metastatic colorectal adenocarcinoma (SW620) cells. The use of ultrasound irradiation as alternative energy input in Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) shortened the reaction time, increased the reaction efficiency and led to the formation of exclusively symmetric bis-heterocycles. DFT calculations showed that triazole formation is exceedingly exergonic and confirmed that the presence of Cu(I) ions is required to overcome high kinetic requirements and allow the reaction to proceed. The influence of various linkers and 6-substituted purine and regioisomeric 7-deazapurine on their cytostatic activity was revealed. Among all the evaluated compounds, the 4-chloropyrrolo[2,3-d]pyrimidine monomer 5f with 4,4′-bis(oxymethylene)biphenyl had the most pronounced, although not selective, growth-inhibitory effect on pancreatic adenocarcinoma (CFPAC-1) cells (IC₅₀ = 0.79 µM). Annexin V assay results revealed that its strong growth inhibitory activity against CFPAC-1 cells could be associated with induction of apoptosis and primary necrosis. Further structural optimization of bis-chloropyrrolo[2,3-d]pyrimidine with aromatic linker is required to develop novel efficient and non-toxic agent against pancreatic cancer.     

Metallocene derivatives as active supports of zirconium‐based catalysts for ethene polymerization

Cyclopentadienyl magnesium chloride (MgClCp) and its functionalized derivatives represent original and interesting supporting materials to heterogenize metallocene catalysts for olefin polymerizations. The synthesis of MgClCp, its functionalization, and the preparation of a catalytic system in which the ZrCl₂(Flu)⁺ moiety is joined on the support through a cyclopentadienyl ligand are reported. This catalyst was tested in ethene polymerization, and both the catalytic activity and properties of the produced polymer were measured. Its performance was compared with that shown by the catalyst ZrCl₂CpFlu employed under the same conditions for both unsupported and conventional supports, such as MgCl₂. The results showed a remarkable improvement in terms of the activity and polymer properties with these heterogenized catalysts. Moreover, this system showed stability toward leaching processes and was characterized by good morphological control of the growing polymer. Finally, catalysts in which [HB(3,5‐Me₂pyrazolyl)₃]ZrCl and [HB(3,5‐Me₂pyrazolyl)₃]ZrClOtBu⁺ moieties were bonded to a functionalized MgClCp^? support were also synthesized and tested. The results showed that the proposed supports could be usefully used to heterogenize tailored metallocene homogeneous catalysts. In fact, new catalysts were prepared that combined the peculiar advantages of both heterogeneous and homogeneous catalysts and overcame the disadvantages of the latter, such as a lack of morphology and reactor fouling. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4243–4248, 2001