Formal asymmetric 1,3-dipolar cycloaddition of azomethine ylides to (S)-2-p-tolylsulfinyl-2-cyclopentenone

Azomethine ylides, derived from iminoesters 1 and DBU in the presence of silver salts, react with (S)-2-p-tolylsulfinyl-2-cyclopentenone 2 in a completely regio- and endoselective manner but with a low facial selectivity, affording a mixture of two cycloadducts 3 and 4. When the ylides were prepared with LHMDS, only one diastereoisomer 3 was obtained in an almost quantitative yield. A nucleophilic addition/ring closure process easily accounts for the stereochemical results. Compounds 3 were transformed into optically pure 4-oxocyclopenta[c]dihydropyrroles and tetrahydropyrroles by elimination of the sulfinyl group.     

Chemical Strategies for Dendritic Magneto-plasmonic Nanostructures Applied to Surface-Enhanced Raman Spectroscopy

Chemical analyses in the field using surface-enhanced Raman scattering (SERS) protocols are expected to be part of several analytical procedures applied to water quality monitoring. To date, these endeavors have been supported by developments in SERS substrate nanofabrication, instrumentation portability, and the internet of things. Here, we report distinct chemical strategies for preparing magneto-plasmonic (Fe₃O₄ : Au) colloids, which are relevant in the context of trace-level detection of water contaminants due to their inherent multifunctionality. The main objective of this research is to investigate the role of poly(amidoamine) dendrimers (PAMAMs) in the preparation of SERS substrates integrating both functionalities into single nanostructures. Three chemical routes were investigated to design magneto-plasmonic nanostructures that translate into different ways for assessing SERS detection by using distinct interfaces. Hence, a series of magneto-plasmonic colloids have been characterized and then assessed for their SERS activity by using a model pesticide (thiram) dissolved in aqueous samples.     

Microcapillary Supersonic Free-jet Injection: Plasma Diagnostics

Supersonic injection of a neutral, ground state gas through a microcapillary nozzle into a low density, weakly ionized, flowing plasma is employed to obtain information on the plasma characteristics. The “zone of silence” of the injected free-jet constitutes a pristine pocket of injected gas, adjustable in size by varying nozzle pressure and diameter of the injector. The shock waves bounding this region exclude massive particles yet transmit electrons, which excite the injected gas to yield radiative emission on lines specific to the gas. Other possible uses of microcapillary injection are discussed.     

Correction: Dermatan sulfate in tunicate phylogeny: Order-specific sulfation pattern and the effect of [→4IdoA(2-Sulfate)β-1→3GalNAc(4-Sulfate)β-1→] motifs in dermatan sulfate on heparin cofactor II activity

After the publication of the work entitled "Dermatan sulfate in tunicate phylogeny: Order-specific sulfation pattern and the effect of [→4IdoA(2-Sulfate)β-1→3GalNAc(4-Sulfate)β-1→] motifs in dermatan sulfate on heparin cofactor II activity", by Kozlowski et al., BMC Biochemistry 2011, 12:29, we found that the legends to Figures 2 to 5 contain serious mistakes that compromise the comprehension of the work. This correction article contains the correct text of the legends to Figures 2 to 5.     

Phenomenology of consciousness from apprehension to judgment

We explore two different moments of human cognition, namely apprehension (A), whereby a coherent perception emerges by recruitment of large neuron groups and judgment (B), whereby memory retrieval of different (A) units coded in a suitable language and comparison of them leads to the formulation of a judgment. The first one has a duration around 1 sec (from 0.5 to 3 sec), it appears as an a-temporal present and its neural correlate is a wide synchronization in the EEG gamma band. It may be described as an interpretation of sensorial stimuli in terms of some stored algorithm, via a Bayes procedure. The second one entails the comparison of two apprehensions acquired at different times, coded in a given language, and retrieved by memory. It lasts around 3 sec and requires self-consciousness, as the judging agent must be well aware that he/she is the same one who faces the two coded apprehensions under scrutiny in order to extract a mutual relation. At variance with (A), (B) does not presuppose an algorithm, but it rather builds a new behavioural model by an inverse Bayes procedure. It will be shown how this build up of a novel model is related to creativity and free will.     

Dimostrazione dell'esistenza di un algoritmo delle divisioni successive per alcuni corpi circolari

Nel presentare ai Lettori questo lavoro, annunciamo con vivo rammarico che l'autore prof.Tito Chella è mancato ai vivi nell'ottobre scorso (1923) a soli 42 anni. Il Chella percorse gli stud? Universitarii in Pisa come allievo della R. Scuola Normale Superiore, presso cui si abilitò con una tesi:Sugli invarianti integrali, pubblicata nel Vol. XI (1908) degli Annali di questa Scuola. Fu valoroso insegnante di matematiche, prima nella Scuola Tecnica di Spezia, poi negli Istituti Tecnici di Foggia, Bari, Firenze e da ultimo in quello di Pisa. Pure aggravato dall'insegnamento secondario, e di salute mal ferma, Egli ha continuato ad occuparsi di studi e ricerche proprie. Il presente lavoro è soltanto un primo saggio di ricerche sulla teoria dei numeri algebrici, che egli aveva avviato con promettente successo, e che vennero malauguratamente interrotte dalla morte.La Direzione