Bio-inspired solutions for locomotion in the gastrointestinal tract: background and perspectives

This paper illustrates a bio-inspired approach to effective, smooth and safe navigation in the human body and, in particular, in the gastrointestinal tract. This idea originates from the medical need to develop more powerful tools for microendoscopy, which is one of the most challenging frontiers of modern medicine. Understanding motion and perception systems of lower animal forms, such as parasites, worms, insects and snakes, can help to design and fabricate bio-inspired robots able to navigate in tortuous, slippery and difficult-to-access cavities of the human body. A preliminary study of a biomimetic adhesion system for the human tissues is presented in this work and some technological implementations are illustrated and discussed. Finally, some issues concerning the goals of smart and reactive locomotion are considered and the most promising and relevant enabling technologies are discussed.     

Usage of SoS methodologies in production system design

Production systems design is a multifaceted task, due to a variety of aspects such as the mutual interdependency between the sub-systems, the variety of configurations and alternative system control strategies, the multiple managerial and “soft” aspects that cast an influence on the behavior of the system. A reasonable number of modeling tools can be applied to production system design, but they tend to divide the problem into unconnected sub-problems whose individual solutions may result in a poor global one. This is despite the fact that production design encompasses all aspects of manufacturing operations, and needs a systemic approach, as clearly shown in practitioner-oriented literature. This paper proposes to apply the “System of Systems” approach to production system design in order to represent their main aspects and support the rational definition of the path leading from corporate strategy to system (re)design.     

Characterization of soil deformation due to blast-induced liquefaction by UAV-based photogrammetry and terrestrial laser scanning

ABSTRACT

Soil liquefaction due to an earthquake can lead to permanent soil deformation and reduction of load-bearing capacity that in turn could act on building stability. Since a quantitative evaluation of post-liquefaction settlements is often very difficult, field scale liquefaction tests, carried out under controlled conditions, such as blast tests, are used to perform a correct quantitative analysis of the liquefaction phenomena. Among the significant parameters related to a blast test, there are the geometric ones, i.e. the extension of the area affected by the blast-induced liquefaction and the corresponding vertical displacements. This article shows the results of a blast test carried out at a trial site located in Mirabello (Ferrara, Italy) from a remote-sensing perspective. Data provided by aerial Structure-from-Motion photogrammetry, supported by terrestrial laser scanning measurements, were used to evaluate the soil deformation that, in the specific case study, aided a geological/geotechnical interpretation of the blast test results. In general, the proposed method can be used to characterize areas affected by blast-induced liquefaction, including those cases where blasting is used as ground improvement technique aimed at mitigating the seismic hazard.     

A one-pot ultrasound-assisted water extraction/cyclodextrin encapsulation of resveratrol from Polygonum cuspidatum

The ultrasound-assisted extraction (UAE) of resveratrol and other polyphenols from Polygonum cuspidatum has been carried out with the aim of developing an efficient and eco-friendly extraction process. The finely milled roots were sonicated (titanium horn, 19.5 kHz) in methanol, in different cyclodextrin water solutions [β-cyclodextrin (β-CD) or hydroxypropyl β-CD (HPβ-CD)] and also in pure water. UAE dramatically increased the yields and cut down extraction times compared to conventional extraction under stirring. Outstanding results have been achieved with the β-CD solution (1.5% w/w); in fact HPLC analysis showed that the selective inclusion properties of CDs toward phenolic stilbenes gave a much cleaner analytical extract profile. This green method gave 7.51 mg of total resveratrol (free + cleaved polydatin glucoside) per gram of dry plant. Thanks to polyphenol encapsulation within CDs, this extract showed excellent water dispersibility, higher stability and an antioxidant power which is comparable to that of the MeOH extract (DPPH, ORAC_FL). These important features should pave the road for its application in food supplements or phytochemical preparations.     

A fair protocol for signing contracts

Two parties, A and B, want to sign a contract C over a communication network. To do so, they must simultaneously exchange their commitments to C. Since simultaneous exchange is usually impossible in practice, protocols are needed to approximate simultaneity by exchanging partial commitments in piece-by-piece manner. During such a protocol, one party or another may have a slight advantage; a fair protocol keeps this advantage within acceptable limits. A new protocol is proposed. It is fair in the sense that, at any stage in its execution, the conditional probability that one party cannot commit both parties to the contract given that the other party can, is close to zero. This is true even if A and B have vastly different computing powers and is proved under very weak cryptographic assumptions     

Ureteral stricture formation after removal of impacted calculi

PURPOSE: We retrospectively evaluated the records of 21 patients a mean of 46.1 years old with ureteral stones that had been impacted for greater than 2 months to determine predisposing factors for stricture formation. MATERIALS AND METHODS: Between January 1993 and September 1996, 21 patients were referred for ureteral stones that had remained unchanged in location for at least 2 months. In 11 patients previous attempts at stone removal had failed. Each patient underwent successful stone extraction by retrograde or percutaneous antegrade ureteroscopy, or laparoscopic or open ureterolithotomy. Outcome was determined by reviewing the clinical records and radiographic studies, including excretory urography and nephrostography. RESULTS: Average duration of stone impaction before definitive treatment was 8.8 months (range 2 to 48) and mean stone size was 10.3 mm. (range 1 to 30). All stones were calcium based. There were 3 proximal, 8 mid and 10 distal ureteral calculi. At a mean followup of 7 months ureteral strictures developed in 5 patients (24%) at the previous stone site. Mean duration of stone impaction was 11 months (range 5 to 17) in patients with stricture versus 8.2 months (range 2 to 48) in those with no stricture. Four of the 5 strictures occurred in patients who had had iatrogenic ureteral perforation during previous unsuccessful attempts at stone removal. CONCLUSIONS: Ureteral stone impaction more than 2 months in duration is associated with a 24% incidence of stricture formation. Ureteral perforation at the site of the stone was identified as the primary risk factor for stricture formation in these cases.     

Morphological differentiation of the conjunctival goblet cells in the chick (Gallus domesticus)

BACKGROUND: These is no consensus in the literature regarding the differentiation of conjunctival goblet cells in vertebrates. METHOD: The conjunctival epithelium of the chick was studied before and after hatching in order to demonstrate the morphological evolution of the goblet cells. The entire conjunctiva was processed for light microscopy either on semithin sections stained with toluidine blue-pironine or on traditional sections stained with Alcian blue pH 2.5-PAS. RESULTS: It was possible to demonstrate that goblet cells underwent remarkable changes in their secretory activity. At 12 h after hatching, isolated Alcian blue-positive cells were present in the fornix. At 24 h after hatching, cells positive for both Alcian blue and PAS were scattered among epithelial cells. Two days after hatching, cells which reacted positively only to PAS were also present. CONCLUSION: It is suggested that the differentiation of conjunctival goblet cells occurs first in the fornix, probably due to the particular vascular environment of this region, and then spreads all over the conjunctiva.     

Highly Efficient Ion‐Tagged Catalyst for the Enantioselective Michael Addition of Aldehydes to Nitroalkenes

The ion‐tagged diphenylprolinol silyl ether 6 very efficiently catalyzes the asymmetric Michael addition of aliphatic aldehydes to nitroalkenes with ee of up to>99.5% at low catalyst loadings (0.25–5 mol%) and using only a slight excess of aldehydes (1.2–2 equiv.). This new organocatalyst can be used with the same outstanding efficiency in a wide variety of solvents and reaction conditions.