Robust and quadratic stability via polytopic set covering

In this paper we consider the problem of covering the image of a given function by a polytope. This problem arises in both the robust and quadratic stability context. We present two main algorithms: the first one performs such a covering and works under quite general assumptions on the nature of the function; the second one is iterative and allows us to improve at will the goodness of the covering. The convergence properties of this algorithm are also discussed. Finally two examples of application of our techniques are presented.     

Synthesis and characterization of P(MMA-AA) copolymers for targeted oral drug delivery

This paper describes the development of pH-sensitive poly(methyl methacrylate-acrylic acid) copolymers for the enteric coating of pharmaceutical products for oral administration. To obtain the dissolution at the desired pH level, different pH-sensitive polymers are available on the market. Usually, for each desired dissolution pH, an ad hoc polymer is designed. Thus, different dissolution pH values could ask for completely different polymers. Instead, the materials proposed in this work are copolymers of the same two monomers, and the different dissolution pH was obtained by changing the volume fraction of the hydrophobic methyl methacrylate monomer to the hydrophilic acrylic acid monomer. Increasing the volumetric percentage of methyl methacrylate causes the polymer to dissolve at increasing pH, until the dissolution does not take place at all, and it is replaced by a slow swelling phenomenon. The copolymers obtained were characterized by differential scanning calorimetry, in order to evaluate their glass transition temperature, and these latter were related to %MMA. The molecular weights of the pure polymers (PAA, PMMA) were measured by intrinsic viscosity, to further validate the glass transition temperatures observed. The dissolution of the copolymers was carefully tested in buffer solutions for a dense set of pH values. A linear relationship between dissolution pH and volumetric percentage of methyl methacrylate was obtained from these measurements. As a result, for any physiological compartment, the copolymer which dissolves at the pH of interest can be easily synthesized.     

Assessment of the load-carrying capacity of multi-span masonry arch bridges using fibre beam elements

An approach that makes use of non-linear beam elements with fibre cross-section has been used for modelling the ultimate behaviour of multi-span masonry arch bridges. The proposed approach proves able to take into account the interaction among the spans and the non-linear material behaviour with low computational effort. In order to validate the use of the model for the assessment of masonry arch bridges, the load-carrying capacity for typical multi-span railway bridges has been evaluated and the results compared to experimental results and to currently used limit analysis methods. It is shown that, by parity of constitutive assumption, the method provides the same results as limit analysis, both in terms of maximum load prediction and hinges position at collapse; however, taking the effective ductility capacity into account, a strong reduction in load-carrying capacity with respect to classical limit analysis was found, depending on rise-to-span arch ratio, piers slenderness and backfill height. The approach is then applied to a seven span viaduct of the Italian railway network, for which the effective mechanical properties of masonry were identified through an experimental campaign on brickwork samples according to the effective material properties surveyed on site.     

Reversing the Psychiatric Effects of Neurodevelopmental Cannabinoid Exposure: Exploring Pharmacotherapeutic Interventions for Symptom Improvement

Neurodevelopmental exposure to psychoactive compounds in cannabis, specifically THC, is associated with a variety of long-term psychopathological outcomes. This increased risk includes a higher prevalence of schizophrenia, mood and anxiety disorders, and cognitive impairments. Clinical and pre-clinical research continues to identify a wide array of underlying neuropathophysiological sequelae and mechanisms that may underlie THC-related psychiatric risk vulnerability, particularly following adolescent cannabis exposure. A common theme among these studies is the ability of developmental THC exposure to induce long-term adaptations in the mesocorticolimbic system which resemble pathological endophenotypes associated with these disorders. This narrative review will summarize recent clinical and pre-clinical evidence that has elucidated these THC-induced developmental risk factors and examine how specific pharmacotherapeutic interventions may serve to reverse or perhaps prevent these cannabis-related risk outcomes.     

Analysis of flamelet leading point dynamics in an inhomogeneous flow

Several studies have utilized “leading points” concepts to explain the augmentation of burning rates in turbulent flames by flow fluctuations. These ideas have been particularly utilized to explain the strong sensitivity of turbulent burning rates to fuel composition. Leading point concepts suggest that the burning velocity is controlled by the velocity of the points on the flame that propagate farthest out into the reactants – thus, they de-emphasize the classical idea that burning velocity enhancement is due to increases in flame surface area. Rather, within this interpretation, flame area creation is the effect, not the cause, of augmented turbulent burning velocities. However, the theory behind the implementation of leading point concepts in turbulent combustion modeling needs further development and the definition of “leading point” has not been fully clarified. For a certain class of steady shear flows, it is straightforward to demonstrate the leading point concept in an intuitive manner, but the problem becomes more complex when the leading points themselves evolve in time. In this paper, we use the G-equation to describe the flame dynamics and, utilizing results for Hamilton–Jacobi equations from the Aubry–Mather theory, demonstrate both the utility and limitations of leading points interpretations for front propagation, at least for deterministic problems. Specifically, we show how the large-time behavior of the solutions is controlled by discrete points on the flame under certain conditions and is, therefore, independent of the rest of the flow field details – a key hypothesis of leading points theories. However, it is possible to find other conditions where the large time behavior of the flame is not controlled by discrete points on the flame, but rather by the velocity field over its entire surface. Moreover, we also show that even in cases where the burning rate is controlled by discrete points, these points are not necessarily the most forward lying points in the flame front. Finally, we consider the case where the laminar flame speed is a function of flame front curvature and derive exact results for the sensitivity of the front speed to the Markstein length, ?, for ? > 0. These solutions explicitly illustrate how the reduction of front displacement speed for increasing ? can be interpreted in terms of leading points dynamics in some cases.     

Gelling Properties of Atlantic Croaker Surimi Processed by Acid or Alkaline Solubilization

ABSTRACT: Textural properties of gels from Atlantic croaker surimi recovered by isoelectric precipitation, following acid (AC) or alkaline (AL) solubilization, were compared with that of conventionally washed (CW) surimi. Gel strengths were in the order of AL > AC > CW, with higher gel strength and deformability induced by microbial transglutaminase addition. None of the surimi treatments evidenced endogenous TGase activity. Salt (2% NaCl) addition had variable effects. Proteolysis was evident by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in gels from all treatments when preincubated at 30 °C or 40 °C.     

Preliminary diagnostic evaluation of submucosal myoma using operative hysteroscopy

BACKGROUND AND AIM: The authors aim to underline the importance of preliminary diagnostic evaluation in the treatment of submucous leiomyoma using hysteroscopy. MATERIALS AND METHODS: The study examined 18 patients monitored at the Institute of Obstetrics and Gynecology of "La Sapienza" University of Rome between January and December 1995 in whom it was possible to make a correct definition of the lesion to be treated (number, site, size, etc.) using 3 different diagnostic methods: hysteroscopy (HS), transvaginal scan (TSV) and transvaginal echohysterography (TVHS) The authors focused attention on three different parameters: leiomyoma size, extension (intracavity/intramural portion) and evaluation of the residual leiomyoma, which are essential for optimal endoscopic resection. RESULTS: HS enabled the number, size, site, origin, base, submucous portion and relations with tube operings to be evaluated, but did not allow the myometrial part of the lesion to be examined. CONCLUSIONS: Integration with TSV, even if this does not allow a precise definition of the extension, highlights the size, site, involvement of myometrial structure and relations with the perimetrium, thus allowing the possibility of evaluating the residual myometrium. Compared to the above methods, TVHS highlights the effective extension (namely the submucous/intramural portion) and localization of the neoformation.     

Architected Polymer Foams via Direct Bubble Writing

Polymer foams are cellular solids composed of solid and gas phases, whose mechanical, thermal, and acoustic properties are determined by the composition, volume fraction, and connectivity of both phases. A new high‐throughput additive manufacturing method, referred to as direct bubble writing, for creating polymer foams with locally programmed bubble size, volume fraction, and connectivity is reported. Direct bubble writing relies on rapid generation and patterning of liquid shell–gas core droplets produced using a core–shell nozzle. The printed polymer foams are able to retain their overall shape, since the outer shell of these bubble droplets consist of a low‐viscosity monomer that is rapidly polymerized during the printing process. The transition between open‐ and closed‐cell foams is independently controlled by the gas used, while the foam can be tailored on‐the‐fly by adjusting the gas pressure used to produce the bubble droplets. As exemplars, homogeneous and graded polymer foams in several motifs, including 3D lattices, shells, and out‐of‐plane pillars are fabricated. Conductive composite foams with controlled stiffness for use as soft pressure sensors are also produced.