Relation equations in residuated lattices

In questa nota si affronta il problema della risoluzione di equazioni matriciali del tipoAX=B, doveA eB sono matrici a valori su un reticolo distributivo residuato rispetto a una moltiplicazione. In particolare, si individua la più grande soluzione di una tale equazione e si danno condizioni relative alle soluzioni minimali.     

Quantification of myocardial viability distribution with Gd(DTPA) bolus-enhanced, signal intensity-based percent infarct mapping

Introduction

A substantial, common shortcoming of the currently used semiautomated techniques for the quantification of myocardial infarct with delayed enhancement magnetic resonance imaging is the assumption that the whole myocardial slab that corresponds to the hyperenhanced tomographic area is 100% nonviable. This assumption is, however, incorrect. To resolve this conflict, we have recently proposed the signal intensity percent-infarct mapping method and validated it in an ex vivo, canine experiment. The purpose of the current study has been the validation of the signal intensity percent-infarct mapping method in vivo, using a porcine model of reperfused myocardial infarct.

Methods

In swines (n=6), reperfused myocardial infarct was generated occluding for 90 min by an angioplasty balloon either the left anterior descending or the left circumflex coronary artery. To obtain DE images, Gd(DTPA) enhanced inversion-recovery fast gradient-echo acquisitions were carried out on day 28 after myocardial infarction. Scanning started 15 min after intravenous injection of 0.2 mmol/kg Gd(DTPA). At the end of the MRI session, the animal was sacrificed and 2,3,5-triphenyltetrazolium chloride staining was used to validate the existence and to determine the accurate size of the myocardial infarct. Tissue samples were taken and stained with hematoxylin-eosin and Masson's trichrome for histological assessment of the infarct and the periinfarct zone. The signal intensity percent-infarct mapping data were compared with corresponding data from the delayed enhancement images analyzed with SI_remote+2S.D. thresholding, and with corresponding triphenyltetrazolium-chloride staining data using Friedman's repeated measure analysis of variance on ranks.

Results

The infarct volume determined by the triphenyltetrazolium chloride, SI_remote+2S.D. and signal intensity percent-infarct mapping methods was 3.04 ml [2.74, 3.45], 13.62 ml [9.06, 18.45] and 4.27 ml [3.45, 6.33], respectively. Median infarct volume determined by SI_remote+2S.D. significantly differed from that determined by triphenyltetrazolium chloride (P<.05). The Bland-Altman overall bias was 12.49% of the volume of the left ventricle. Median infarct volume determined by signal intensity percent-infarct mapping, however, did not differ significantly (NS) from that obtained by triphenyltetrazolium chloride. Signal intensity percent-infarct mapping yielded only a 1.99% Bland-Altman overall bias of the left ventricular volume.

Conclusions

This in vivo study in the porcine reperfused myocardial infarct model demonstrates that signal intensity percent-infarct mapping is a highly accurate method for the determination of the extent of myocardial infarct. MRI images for signal intensity percent-infarct mapping are obtained with the pulse sequence of conventional delayed enhancement imaging and are acquired within clinically acceptable scanning time. This makes signal intensity percent-infarct mapping a practical method for clinical implementation.     

Airborne nanoparticle exposures associated with the manual handling of nanoalumina and nanosilver in fume hoods

Manual handling of nanoparticles is a fundamental task of most nanomaterial research; such handling may expose workers to ultrafine or nanoparticles. Recent studies confirm that exposures to ultrafine or nanoparticles produce adverse inflammatory responses in rodent lungs and such particles may translocate to other areas of the body, including the brain. An important method for protecting workers handling nanoparticles from exposure to airborne nanoparticles is the laboratory fume hood. Such hoods rely on the proper face velocity for optimum performance. In addition, several other hood design and operating factors can affect worker exposure. Handling experiments were performed to measure airborne particle concentration while handling nanoparticles in three fume hoods located in different buildings under a range of operating conditions. Nanoalumina and nanosilver were selected to perform handling experiments in the fume hoods. Air samples were also collected on polycarbonate membrane filters and particles were characterized by scanning electron microscopy. Handling tasks included transferring particles from beaker to beaker by spatula and by pouring. Measurement locations were the room background, the researcher’s breathing zone and upstream and downstream from the handling location. Variable factors studied included hood design, transfer method, face velocity/sash location and material types. Airborne particle concentrations measured at breathing zone locations were analyzed to characterize exposure level. Statistics were used to test the correlation between data. The test results found that the handling of dry powders consisting of nano-sized particles inside laboratory fume hoods can result in a significant release of airborne nanoparticles from the fume hood into the laboratory environment and the researcher’s breathing zone. Many variables were found to affect the extent of particle release including hood design, hood operation (sash height, face velocity), work practices, type and quantity of the material being handled, room conditions, and the adequacy of the room exhaust.

Oxidative decarboxylation of arylacetic acids by means of tetrabutylammonium periodate

Tetrabutylammonium periodate (TBAPI) in refluxing dioxane is able to convert arylacetic acids into the corresponding nor-aldehydes in good yields.     

Comparison of methods for the determination of ochratoxin A in wine

Different analytical methods for the determination of ochratoxin A (OTA) in wine have been compared. Sample clean-up was based on solid-phase extraction (SPE) with (i) immunoaffinity or (ii) RP-18 sorbent materials applying different experimental protocols. The detection of OTA was accomplished with high-performance liquid chromatography (HPLC) combined either with electrospray ionisation (ESI) tandem mass spectrometry (MS-MS) or fluorescence detection (FL). Comparative method evaluation was based on the investigation of 18 naturally contaminated red wine samples originating from different European countries. The analytical results are discussed in view of the respective method validation data and the corresponding experimental protocols. In general, analytical data obtained with RP-18 SPE combined with LC-MS-MS detection and immunoaffinity extraction combined with FL offered comparable good results in the sub-ppb concentration level indicating that high selectivity of either the sample clean-up or, alternatively the detection system are equally well-suited to guarantee an accurate OTA analysis in wine.     

High-resolution structures of large ribosomal subunits from mesophilic eubacteria and halophilic archaea at various functional States

Structural analysis of the recently determined high resolution structures of the small and the large ribosomal subunits from three bacterial sources, assisted by the medium resolution structure of a complex of the entire ribosome with three tRNAs, led to a quantum jump in our understanding of the process of the translation of the genetic code into proteins. Results of these studies highlighted dynamic aspects of protein biosynthesis; illuminated the modes of action of several antibiotics; indicated strategies adopted by ribosomes for maximizing their functional activity and revealed a wealth of architectural elements, including long tails of proteins penetrating the particle s cores and stabilizing the intricate folds of the RNA chains. Binding of substrate analogues showed that the decoding and the peptide-bond formation are accomplished mainly by RNA. However, several proteins may be functionally relevant in directing the mRNA and in mediating the proper orientation of the tRNA molecules within the ribosomal rRNA frame. Elements involved in intersubunit contacts or in substrate binding are inherently flexible, but maintain well-ordered characteristic conformations in unbound particles. The ribosomes utilize this conformational variability for optimizing their efficiency and minimizing non-productive interactions, hence disorder of functionally relevant features may be linked to less active conformations or to far from physiological conditions. Clinically relevant antibiotics bind almost exclusively to rRNA. In the small subunit they affect the decoding accuracy or limit conformational mobility and in the large subunit they either interfere with substrate binding, by interacting with components of the peptidyl transferase cavity, or hinder the progression of the growing peptide chain.     

Identification of organic compounds by microscopy and X-ray diffractometry

Summary Primary and secondary crystallographic constants can be utilized conveniently for identifications of crystalline organic and inorganic materials by microscopy and X-ray diffractometry. Several specific properties can be measured under the petrographical microscope, including optic axial angle, character, dispersion, and in addition, refractive index directions can be established. The d spacings and their intensities as determined with the X-ray diffractometer serve to identify crystalline materials. The two instruments should be considered as supplementary tools for identifying crystals.Both instruments supply a means for identification and semiquantitative analysis of mixed crystal systems. Data are presented for the systems: acetic-propionic p-bromoanilides and acet-propion-2.4-dinitro-phenylhydrazones.

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Zusammenfassung Primäre und sekundäre kristallographische Konstanten können zur Identifizierung kristallisierter organischer und anorganischer Stoffe auf mikroskopischem Wege und durch Röntgendiffraktometrie gut herangezogen werden. Einzelne spezifische Eigenschaften können unter dem petrographischen Mikroskop gemessen werden, so der optische Achsenwinkel, der Charakter, die Dispersion. Außerdem kann man Angaben über den Brechungsindex erhalten. Die mit dem Röntgendiffraktometer bestimmten Netzebenenabstände d und deren Intensitäten dienen zur Identifizierung kristallisierter Stoffe. Die beiden Instrumente sind als Hilfsmittel zur Erkennung von Kristallen anzusehen.Sie bieten die Möglichkeit zur Identifizierung und halbquantitativen Analyse von Mischkristallsystemen. Daten für die Systeme Essigsäure-Propionsäure-p-Bromanilid und Acetaldehyd-Propionaldehyd-2,4-Dinitrophenylhydrazon werden mitgeteilt.

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Résumé Les constantes cristallographiques primaires et secondaires sont utilisables pour l'identification de composés cristallins organiques et minéraux par microscopie et diffractométrie de rayons X. Il est possible de mesurer diverses propriétés spécifiques sous le microscope pétrographique, savoir: l'angle des axes optiques, le caractère et la dispersion optiques. Il est en outre possible de déterminer les directions des indices de réfraction primaires. Les espacements «d» et leurs intensités déterminés par le diffractomètre à rayons X permettent d'identifier les substances cristallines. Les deux instruments doivent être considérés comme complémentaires pour l'identification de cristaux. Chacun d'entre eux fournit un moyen d'identification et d'analyse semi quantitative des systèmes de cristaux mixtes. On rend compte de résultats obtenus pour les systèmes: p-bromoanilides acétique et propionique ainsi que 2, 4-dinitro phénylhydrazones de l'acétaldéhyde et du propionaldéhyde.