Multi-Dimensional Pattern Matching with Dimensional Wildcards: Data Structures and Optimal On-Line Search Algorithms

We introduce a new multidimensional pattern matching problem that is a natural generalization of string matching, a well studied problem[1]. The motivation for its algorithmic study is mainly theoretical. LetA[1:n₁,…,1:n_d] be a text matrix withN = n₁…n_dentries andB[1:m₁,…,1:m_r] be a pattern matrix withM = m₁…m_rentries, whered ≥ r ≥ 1 (the matrix entries are taken from an ordered alphabet Σ). We study the problem of checking whether somer-dimensional submatrix ofAis equal toB(i.e., adecisionquery).Acan be preprocessed andBis given on-line. We define a new data structure for preprocessingAand propose CRCW-PRAM algorithms that build it inO(log N) time withN²/n_maxprocessors, wheren_max = max(n₁,…,n_d), such that the decision query forBtakesO(M) work andO(log M) time. By using known techniques, we would get the same preprocessing bounds but anO((^d_r)M) work bound for the decision query. The latter bound is undesirable since it can depend exponentially ond; our bound, in contrast, is independent ofdand optimal. We can also answer, in optimal work, two further types of queries: (a) anenumerationquery retrieving all ther-dimensional submatrices ofAthat are equal toBand (b) anoccurrencequery retrieving only the distinct positions inAthat correspond to all of these submatrices. As a byproduct, we also derive the first efficient sequential algorithms for the new problem.     

A Convenient ar-SE Laboratory Experiment Avoiding the Use of Sulfuric Acid: the Nitration of Diphenylmethane in Ch2Cl2

The nitration of diphenylmethane to three main isomeric dinitro derivatives, performed with nitric acid in dichloromethane, is proposed as an organic laboratory experiment showing a number of advantages over typical aromatic nitrations in sulfuric acid.     

Ni‐Catalyzed Asymmetric Cycloisomerization of Dienes by Using TADDOL Phosphoramidites

A library of α,α,α,α‐tetraaryl‐1,3‐dioxolane‐4,5‐dimethanol (TADDOL)‐based phosphoramidites has been synthesized and applied in the Ni‐catalyzed cycloisomerization of different dienes. Through the systematic variation of the three structural motifs of the lead structure, that is, the amine moiety, the protecting group, and the aryl substituents, the ligand features could be optimized for the asymmetric cycloisomerization of the model substrate diethyl diallylmalonate. The substrate scope of the new catalytic system was extended to other diallylic substrates, including unsymmetrical dienes. Overall remarkably high activities of up to approximately 13 500 h^?1, very high selectivities toward five‐membered exo‐methylenecyclopentanes, and enantioselectivities of up to 92 % ee have been achieved.     

Weighted residuals as a basis of a general solution method in elasticity

Summary It is shown that the general integral form of the elastic equilibrium equations obtainable through the weighted residuals agrees with the variational formulation given by the extremum conditions of the Washizu functional allowing a complete relaxation of the interelement continuity requirements.

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Sommario Si mostra che la forma generate integrale del sistema di equazioni dell'equilibrio elastico a cui conduce il metodo dei residui con fattori ponderali concorda con la formulazione variazionale fornita dalle condizioni di estremo del funzionale di Washizu che deriva da quello di Hellinger-Reissner mediante sblocco completo dei vincoli di continuità fra regioni contigue.

     

Molecular cloning and transgenic expression of a synthetic human erythropoietin gene in tobacco

Erythropoietin (EPO) is a hormone belonging to a group of hematopoietic growth factors that control the proliferation and differentiation of bone marrow cells. It induces the production of erythrocytes, thereby increasing the amount of circulating hemoglobin and oxygen. Previous attempts to transgenically express human EPO in plants failed to succeed because the plants exhibited abnormal morphology and infertility. In the present work, we describe the generation of fertile transgenic tobacco plants able to express a synthetic version of human EPO. A 582-bp fragment of the human EPO gene was synthesized using a PCR-based method and ligated into pCR-Blunt. After sequencing, the human EPO fragment was transferred to pWUbi.tm1 and the expression cassette was then transferred to the binary vector pWBVec4a. After Agrobacterium-mediated transformation of Nicotiana tabacum SR1 plants, integration of the transgene into T₀ and T₁ plant genomes was confirmed by PCR. The human EPO gene was found to be expressed in tobacco leaves at the mRNA and protein levels. Self-crossing allowed us to obtain T₁ plants exhibiting Mendelian segregation of the transgene. None of the plants presented any kind of malformation or deformity.     

Clickable functionalization of liposomes with the gH625 peptide from Herpes simplex virus type I for intracellular drug delivery

Liposomes externally modified with the nineteen residues gH625 peptide, previously identified as a membrane‐perturbing domain in the gH glycoprotein of Herpes simplex virus type I, have been prepared in order to improve the intracellular uptake of an encapsulated drug. An easy and versatile synthetic strategy, based on click chemistry, has been used to bind, in a controlled way, several copies of the hydrophobic gH625 peptide on the external surface of 1,2‐dioleoyl‐sn‐glycero‐3‐phosphocholine (DOPG)‐based liposomes. Electron paramagnetic resonance studies, on liposomes derivatized with gH625 peptides, which are modified with the 2,2,6,6‐tetramethylpiperidine‐1‐oxyl‐4‐amino‐4‐carboxylic acid (TOAC) spin label in several peptide positions, confirm the positioning of the coupled peptides on the liposome external surface, whereas dynamic light scattering measurements indicate an increase of the diameter of the liposomes of approximately 30 % after peptide introduction. Liposomes have been loaded with the cytotoxic drug doxorubicin and their ability to penetrate inside cells has been evaluated by confocal microscopy experiments. Results suggest that liposomes functionalized with gH625 may act as promising intracellular targeting carriers for efficient delivery of drugs, such as chemotherapeutic agents, into tumor cells.     

On-chip pre-concentration and complexation of [¹⁸F]fluoride ions via regenerable anion exchange particles for radiochemical synthesis of Positron Emission Tomography tracers

Microfluidic approaches have demonstrated a relevant impact on radiochemical reactions involving Positron Emission Tomography (PET) nuclides, due to shorter reaction times and smaller precursor quantities. However, little attention has been given to the integration of the initial pre-concentration and drying of radioactive [(18)F]fluoride ions, required for the labeling of radiotracer compounds. In this work we report the design, fabrication and implementation of a glass microfluidic device filled with recyclable anion exchange particles for the repeated recovery of [(18)F] and [(19)F]fluoride ions. The device was first tested with non radioactive [(19)F]fluoride ions and it was shown to repeatedly trap and elute >95% fluoride over 40 successive experimental runs with no decrease in efficiency. The same device was then tested for the trapping and release of [(18)F]fluoride ions over 20 experiments with no measurable decrease in performance. Finally, the [(18)F]fluoride ions were eluted as a K(18)F/K2.2.2 complex, dried by repeated dissolution in acetonitrile and evaporation of residual water, and reacted with ethyl ditosylate (EtDT) leading to the desired product ([(18)F]fluoroethyltosylate) with 96 ± 3% yield (RCY). The overall time needed for conditioning, trapping, elution and regeneration was less than 6 min. This approach will be of great benefit towards an integrated platform able to perform faster and safer radiochemical synthesis on the micro-scale.     

Thiazolium-catalyzed intermolecular Stetter reaction of linear and cyclic alkyl α-diketones

An efficient method for the N-heterocyclic carbene (NHC)-catalyzed conjugate addition of acetyl anions to various α,β-unsaturated acceptors (Stetter reaction) has been optimized by using 2,3-butandione (biacetyl) as an alternative surrogate of acetaldehyde. The disclosed procedure proved to be compatible with microwave dielectric heating for reaction time reduction and with the use of different linear α-diketones as acyl anion donors (e.g. 3,4-hexanedione for propionyl anion additions). Moreover, the unprecedented umpolung reactivity of cyclic α-diketones in the atom economic nucleophilic acylation of chalcones is herein presented. Mechanistic aspects of the thiazolium-based catalysis involving linear and cyclic α-diketone substrates are also discussed.     

Silver(I) and copper(I) complexes supported by fully fluorinated 1,3,5-triazapentadienyl ligands

Synthesis of the perfluorinated 1,3,5-triazapentadiene [N{(CF(3))C(C(6)F(5))N}(2)]H and the use of its conjugate base as a supporting ligand for the isolation of silver(i) and copper(i) complexes are reported. Some of the related chemistry involving [N{(C(3)F(7))C(C(6)F(5))N}(2)](-) (that has bulkier -C(3)F(7) groups on the 1,3,5-triazapentadienyl ligand backbone) is also presented. X-ray crystallographic data show a wide variety of structures ranging from intermolecular, hydrogen-bonded chain structure for [N{(CF(3))C(C(6)F(5))N}(2)]H with a twisted W-shaped N(3)C(2) core, monomeric [N{(CF(3))C(C(6)F(5))N}(2)]Ag(CN(t)Bu)(2) and [N{(C(3)F(7))C(C(6)F(5))N}(2)]Ag(CN(t)Bu)(2) where the κ(1)-bonded triazapentadienyl ligand bonding to the metal fragment via the central nitrogen atom, monomeric [N{(CF(3))C(C(6)F(5))N}(2)]Ag(PPh(3))(2) and [N{(C(3)F(7))C(C(6)F(5))N}(2)]Ag(PPh(3))(2) that feature κ(1)-bonded triazapentadienyl ligand bonding to the metal fragment via one of the terminal nitrogen atoms, to that of the monomeric [N{(CF(3))C(C(6)F(5))N}(2)]Cu(CN(t)Bu)(2) containing a κ(2)-bonded triazapentadienyl ligand and a U-shaped NCNCN ligand backbone. The isocyanide adducts show relatively high ν(CN) values in the IR spectra.