178 research outputs found
Chiral Allylsilanes Derived From Naturally-occurring Alpha-amino-acids
No full textNatural occurring alpha-amino acids, N-butoxycarbonyl protected and converted into the corresponding aldehydes, were transformed into (Z)-alkenes 2-7 by Wittig olefination. Metalation with butyllithium-potassium tert-butoxide gave, after reaction with trimethylsilyl chloride, chiral allylsilanes [e.g., (Z)-(4S)-4-tert-butoxycarbonylamino-6-methyl-1-trimethylsilyl-2-heptene (10)]. The condensation of two of these with acetyl chloride-titanium(IV) chloride is also reported
Regulation of fla/che transcription in Bacillus subtilis
No full textfla/che is the master operon for motility in Bacillus subtilis and codes for most of the flagellum components and for the alternative sigma factor sigD, the latter responsible for transcription of the flagellin gene hag and additional genes. Despite fla/che being the subject of numerous investigations over the last 20 years, there are still open questions concerning the fine tuning of its expression and the signals leading to the enhancement of its transcription, necessary for swarming motility.
Two promoter sequences drive fla/che transcription: PD3(fla/che) and PA(fla/che). PD3(fla/che), transcribed by the internal SigD, is not sufficient to promote motility, while PA(fla/che) is both necessary and sufficient for fla/che expression and swimming and swarming motility.
Several studies have established that fla/che operon expression is modulated by the DegS/DegU two-component system, although the role of phosphorylated DegU is still not clear.
Also SwrA, a protein essential for swarming and for full swimming motility, acts as a positive regulator of fla/che, by stimulating transcription from PA(fla/che). An autoregulatory circuitry exists between SwrA and fla/che, because swrA transcription is sigD-dependent, and in turn fla/che - and thus sigD - transcription is promoted by SwrA; this loop maintains both fla/che and swrA expression ON.
The molecular function of SwrA has remained thus far unknown. In fact, SwrA does not bear any resemblance to any characterized protein, nor does it contain DNA binding or other functional domains that can give a hint about its molecular role.
We have addressed the impact of DegU phosphorylation and the role of SwrA on fla/che expression.
We have demonstrated a cooperative effect between SwrA and DegU in enhancing PA(fla/che) activity, which depends on DegU phosphorylation. We have also evidences that DegU is a dual-function regulator, since it can also act as a repressor for PA(fla/che).
Furthermore, we have observed that PD3(fla/che) and sigD constitute another positive feedback loop that contributes in maintaining fla/che expression ON. This loop is alternative to the one that is promoted by SwrA, and thus represents a sort of contingency plan for motility
La relazione dell’Ispettore Alessandro Parone sullo stato dell’istruzione primaria nel circondario di Siracusa (1864)
No full textIl presente contributo di ricerca intende approfondire lo stato dell’istruzione elementare del Circondario di Siracusa, all’indomani dell’unificazione del Regno d’Italia, quando l’ordinamento scolastico previsto dal Casati, attraverso il decreto Mordini del 17 ottobre 1860, venne esteso in Sicilia. Oggetto di studio particolareggiato di questa ricerca sarà la dettagliata relazione dell’Ispettore circondariale Alessandro Parone, una fonte inedita dalla cui analisi è possibile trarre interessanti informazioni sul reale andamento dell’istruzione primaria nei comuni e nelle borgate del Circondario di Siracusa, nell’arco temporale compreso tra il novembre del 1862 e l’agosto del 1864. This research intends to deepen the state of elementary education in the Syracuse district, after the unification of the Kingdom of Italy, when the school system envisaged by Casati, through the Mordini decree of 17 October 1860, was extended in Sicily. The subject of detailed study of this research will be the detailed report of the District Inspector Alessandro Parone, an unpublished source from whose analysis it is possible to draw interesting information on the real trend of primary education in the municipalities and villages of the Syracuse district, over the period of time. between November 1862 and August 1864
Azide cyclizations with acetylenic silyl ketone: a general access to functionalized 1,2,3-triazolylacylsilanes and aldehydes
No full textGait and Anthropometric Profile Biometrics: A Step Forward
No full textEmerging biometrics based on the measurements of body dynamic and static characteristics have gained increased importance in all the surveillance environments where the security is a mandatory priority. Some technology branches are involved to find unobtrusive solutions for authentication systems, where the human subject should not take care of the system itself so that he/she is free to perform his/her normal actions. In the first part of the chapter a novel gait recognition system is presented that introduces the use of range data for gait signal analysis. In the second part of the chapter, a description of system based on a sensing seat for event-related continuous authentication purpose in office and car scenarios is presented. Both biometric technologies introduce new means of verifying the user identity, by exploiting the analysis of common and every-day activities recorded in an unobtrusive manner and their recognition accuracy has been seen to be very high in the performed experiments
Measurement of the order parameter and its spatial fluctuations across Bose-Einstein condensation
No full textA Simple Regiocontrolled and Stereocontrolled Synthesis of Alpha-branched Allylsilanes
No full text(Z)- or (E)-Allylsilanes were consecutively treated with butyllithium in the presence of potassium tert-butoxide ("Schlosser's base") and methyl iodide or butyl iodide. The alkylation of the allylmetal intermediate occurred mainly or exclusively at the α-position, next to the heteroatom, and the configuration of the double bond was controlled. © 1988
Microwave-activated synthesis of thiazolo[5,4-d]thiazoles by a condensation/oxidation sequence
No full textA microwave-assisted preparation of symmetrical thiazolo[5,4-d]thiazoles from the corresponding aldehydes is presented. The two-step reaction sequence comprises the condensation of aldehydes with dithiooxamide followed by oxidation/aromatization with 1,4-benzoquinone derivatives. The new procedure provides the desired products in good yields and in most cases allows reduction of the excess of aldehyde employed in the process compared to previous methodologies. For the first time, application of the reaction both on aromatic and aliphatic aldehydes is demonstrated. © 2014 The Royal Society of Chemistry
Industrial Synthesis Design With Low Environmental Impact In The Pharma Industry
No full textThe key concepts of industrial process design are discussed. Two industrial synthesis of 7ACA and Erlotinib hydrochloride centred on the use of enzymatic and organometallic catalysis are described
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