Fiber-top cantilevers: a new sensor on the tip of a fiber

Micromachined cantilevers are the most elementary example of miniaturized sensors. A free-standing rectangular beam can often detect changes in the chemical, biological and physical properties of the surroundings with sensitivity comparable to much more complicated devices. It is therefore not surprising that this simple design is still at the heart of several scientific instruments

Fiber-top cantilever:a new generation of micromachined sensors for multipurpose applications

Fiber-top cantilevers are new monolithic devices obtained by carving a cantilever out of the edge of a single-mode optical fiber. Here we report evidences of their potential impact as sensing devices for multipurpose applications

Ab initio molecular dynamics study of water oxidation reaction pathways in mono-ru catalysts

Solid state NMR/Biophysical Organic Chemistr

Biotransformation with whole microbial systems in a continuous flow reactor : resolution of (RS)-flurbiprofen using Aspergillus oryzae by direct esterification with ethanol in organic solvent

Cell-bound lipases of dry mycelium of Aspergillus oryzae were used in organic solvent for the resolution of racemic flurbiprofen by direct esterification with ethanol in a flow-chemistry reactor. Under flow conditions a significant reduction of the reaction time and an increase of the enantioselectivity were achieved compared to the batch mode. Moreover, the process was implemented by adding an in-line purification step integrated with the racemization of the unreacted flurbiprofen directly into a polymer-supported resin

SYNTHESIS AND BIOLOGICAL EVALUATION OF NEW CTP SYNTHETASE INHIBITORS AS NEW POTENTIAL AGENTS FOR THE TREATMENT OF AFRICAN TRYPANOSOMIASIS.

Cytidine triphosphate synthetase (CTPS), a glutamine amidotransferase (GAT) responsible for the de novo synthesis of CTP, was recently suggested as a potential drug target for the treatment of Human African Trypanosomiasis, a parasitic disease caused by Trypanosoma brucei. Acivicin, a natural antitumor antibiotic, is a well-known inhibitor of enzymes belonging to the GAT family. Its CTPS inhibitory activity has been related to the observed trypanocidal activity in bloodstream T. brucei cell cultures. The aim of this project was the design and synthesis of Acivicin analogues characterized by an increased affinity and selectivity for CTPS, as potential new trypanocidal agents with low toxicity against human cells. The results obtained have shown that substituting the 3-Cl- with a 3-Br-isoxazoline increased the inhibitory potency of Acivicin against the target enzyme CTPS three fold, while the substitution with a 3-MeO- group produced a complete loss of the activity, confirming the important role played by the leaving group in the C-3 position of the isoxazoline ring. Interestingly, the three-fold increase of the CTPS inhibitory potency translates into a twelve fold increase of the in vitro anti-trypanosomal activity with a concomitant increase of the selectivity index relative to human cells. Another important finding of the present research project is that the inhibitory activity against CTPS can be increased by applying a molecular complication approach, that means inserting groups able to establish additional interaction with the binding pocket of the enzyme. This strategy has been pursued thanks to the synthesis of N1-substituted-pyrazoline analogues of acivicin. The analysis of the enzymatic activity and the in vitro anti-trypanosomal activity of all the derivatives under study shows that an increased inhibitory activity towards CTPS may produce a great increase of the anti-trypanosomal activity but this cannot be taken as a general rule, since other important factors may play a role, notably the ability of the molecules to penetrate into the target cells

Tracking the decoy:Maximizing the decoy effect through sequential experimentation

Contains fulltext : 161644.pdf (publisher's version ) (Open Access)The decoy effect is one of the best known human biases violating rational choice theory. According to a large body of literature, people may be persuaded to switch from one offer to another by the presence of a third option (the decoy) that, rationally, should have no influence on the decision-making process. For example, when asked to choose between a laptop with a good battery but a poor memory and a laptop with a poor battery but a good memory, customers may be induced to shift their preference if the offer is accompanied by a third laptop that has a battery as good as the latter but even worse memory - an effect that has clear applications in marketing practice. Surprisingly, renowned decoy studies have resisted replication, inducing scholars to challenge the scientific validity of the phenomenon and question its practical relevance. Using a treatment allocation scheme that takes inspiration from the lock-in amplification schemes used in experimental physics, we were able to explore the entire range of decoy attribute values and demonstrate that some of the reproducibility issues reported in the literature result from a suboptimal initial conditions. Furthermore, we demonstrate that our approach is able to sequentially identify the features of the decoy that maximize choice reversal. We thus reinstate the scientific validity and practical relevance of the decoy effect and demonstrate the use of lock-in amplification to optimize treatments.9 p

Carving fiber-top optomechanical transducers from an optical fiber

In a recent paper (Iannuzzi et al 2006 Monolithic fiber-top sensor for critical environments and standard applications Appl. Phys. Lett. 88 053501) we have presented the principle of the fiber-top position sensor, having a monolytical structure carved out of a single-mode optical fiber. The device alleviates sensing in a critical environment via interferometric readout, and\ud because of its monolithic construction, facilitates plug-and-play utilization without alignment. In this paper we describe the fabrication method of a similar device which, however, was also equipped with a pyramidal tip on\ud the top of the cantilever, an important detail for future implementation in scanning probe microscopy. A silicon surface was then periodically put in contact and moved out of contact with the device. The output signal\ud resembles force curves that can be similarly obtained with atomic force microscopes

A fiber-top cantilever for hydrogen detection

We report on the realization of a chemical sensor based on fiber-top design. The device was obtained by carving a cantilever out of the cleaved edge of an optical fiber. The cantilever was coated with a thin palladium layer and alternatively exposed to hydrogen enriched gaseous mixtures and hydrogen free atmosphere. The sensor was capable to unambiguously distinguish hydrogen absorption and desorption throughout several cycles. Our experiment demonstrates that fiber-top chemical sensors might represent an interesting alternative to commonly used detectors. \ud \u

Monolithic fiber-top sensor for critical environments and standard applications

We present a monolithic device obtained by carving a cantilever on the top of a single-mode optical fiber. We show that the vertical position of the cantilever can be determined with accuracy comparable to atomic force microscopes and other commonly used scientific instruments. The device does not require any alignment procedure and can be used in critical environments as well as in standard applications