Specificity of Infant Digestive Conditions: Some Clues for Developing Relevant In Vitro Models

Digestion of nutrients is an essential function of the newborn infant gut to allow growth and development and understanding infant digestive function is essential to optimize nutrition and oral drug delivery. Ethical considerations prohibit invasive in vivo trials and as a consequence in vitro assays are often conducted. However, the choice of in vitro model parameters are not supported by an exhaustive analysis of the literature and do not mimic precisely the digestive conditions of the infant. This review contains a compilation of the studies which characterized the gastroduodenal conditions in full-term or preterm infants of variable postnatal age from birth up to six months. Important data about healthy full-term infants are reported. The enzymatic (type of enzymes and level of activity) and nonenzymatic (milk-based diet, frequency of feeding, bile salt concentrations) conditions of digestion in infants are shown to differ significantly from those in adults. In addition, the interindividual and developmental variability of the digestive conditions in infants is also highlighted.     

On the role of the calcination step in the preparation of active (superacid) sulfated zirconia catalysts

In the preparation of active SO₄-ZrO₂ catalysts, several steps involving various chemical and/or physical processes are necessary. In particular it has been reported that, after sulfation of amorphous Zr hydrates, a calcination atT _calc>773 K is needed to guarantee the crystallization of ZiO₂ in the tetragonal phase. By the use of a stabilized tetragonal ZrO₂, it is here demonstrated that a calcination atT _calc>773 K is indeed necessary for all SO₄-ZrO₂ systems, and that its actual role is the selective elimination of sulfates from highly energetic crystallographic defects. The calcination step atT _calc>773 K so creates the conditions for the formation of strong Lewis acid centres, that are necessary in the catalytic process, and the presence of which is here monitored spectroscopically by the reversible adsorption of carbon monoxide.     

GUEST EDITORIAL: PAPERS IN SENSING AND IN REASONING (MARCO SOMALVICO MEMORIAL ISSUE)

Recently, we observed a great movement of Internet users from blogs and wiki to Myspace, Facebook, Twitter, and Plurk. To increase profit margins, identifying the service factors that attract customers to join a new virtual community is crucial for website enterprises. Most works focus on social networks, success factors, and reasons for participating. Relatively few works have attempted to address this issue. Additionally, feature selection techniques have been widely used to extract crucial attributes. However, domain knowledge, which is hard to obtain, is needed to select meaningful features. Therefore, this work proposes a Kano's model based Neural Network (KANN) method combining Kano's model and neural networks to identify the key service factors. Finally, a real case study of a survey of virtual community users is provided to identify the key service factors.     

Stochastic maximum principle for SPDEs with noise and control on the boundary

In this paper we prove necessary conditions for optimality of a stochastic control problem for a class of stochastic partial differential equations that is controlled through the boundary. This kind of problem can be interpreted as a stochastic control problem for an evolution system in a Hilbert space. The regularity of the solution of the adjoint equation, that is a backward stochastic equation in infinite dimension, plays a crucial role in the formulation of the maximum principle.     

Oxidative transformation of aqueous phenolic mixtures by birnessite-mediated catalysis

The catalytic efficiency of birnessite in the removal of catechol, hydroxytyrosol, methylcatechol and m-tyrosol, four phenols commonly present in polluted wastewaters, was studied in mono-substrate solutions or in mixtures of two, three, and four substrates. In single phenolic solutions the transformation order of phenols was catechol>hydroxytyrosol>methylcatechol>m-tyrosol. With phenolic mixtures different responses were observed and the amount of each phenol transformed and the crossing effects among the various phenols depended on the type and number of phenols present in the mixture. In particular, general inhibitory effects were observed for hydroxytyrosol and m-tyrosol that were transformed less when present in combination with the other phenols. By contrast the effects by the presence of more than one phenol were basically annulled for catechol and methylcatechol at 24 h incubation in all the mixtures. A simultaneous, but often no stoichiometric, release of soluble Mn2+ in the reaction mixtures occurred. The multi-substrate systems were designed to mimic birnessite-mediated oxidative processes that could occur under field conditions. Therefore they could be of great interest to environmental and soil science. The use of birnessite as a potential tool for an effective detoxification and recovery of phenol-polluted systems could be also envisaged.     

Carbonic anhydrase inhibitors: binding of indanesulfonamides to the human isoform II

Indanesulfonamides are interesting lead compounds for designing selective inhibitors of the different isoforms of the zinc enzyme Carbonic Anhydrase (CA). Herein, we report for the first time the X-ray crystal structure of two such derivatives, namely indane-5-sulfonamide and indane-2-valproylamido-5-sulfonamide, in complex with the physiologically dominant human isoform II. The structural analysis reveals that, although these two inhibitors have quite similar chemical structures, the arrangement of their indane ring within the enzyme active site is significantly diverse. Thus, our findings suggest that the introduction of bulky substituents on the indane-sulfonamide ring may alter the binding mode of this potent class of CA inhibitors, although retaining good inhibitory properties. Accordingly, the introduction of bulky tail moieties on the indane-sulfonamide scaffold may represent a powerful strategy to induce a desired physicochemical property to an aromatic sulfonamide or to obtain inhibitors with diverse inhibition profiles and selectivity for various mammalian CAs.     

Morphostructural and immunohistochemical study on the role of metallothionein in the detoxification of heavy metals in Apis mellifera L., 1758

Honey is a valuable food produced by bees from sugary substances that they gather in nature. The transformation the nectar into honey, by bees, is long and complex. Except for honey, where heavy metals are absent or are found only in traces, the bees and their products have always been considered excellent biomarkers of such contaminants. We have assumed that the absence of heavy metals in honey is due to the presence of a detoxification system in the digestive system of bees, which involves metallothioneins, proteins that have a role in the homeostatic control of essential and non‐essential metals. We have placed the beehives in three different zones: industrial, urban and rural. Investigations were carried out with ICP‐MS method for the detection of heavy metals in the guts of honey bees and honey. The metallothioneins have been identified by Immunohistochemical and Western‐blotting analisys. The investigations have shown the presence of heavy metals only in bees guts but not in honey, while the presence of metallothionein has been highlighted only in epithelium of the honey sac, demonstrating the existence of an efficient system of detoxification of heavy metals.     

Mixed Nanosized Polymeric Micelles as Promoter of Doxorubicin and miRNA‐34a Co‐Delivery Triggered by Dual Stimuli in Tumor Tissue

Dual stimuli‐sensitive mixed polymeric micelles (MM) are developed for co‐delivery of the endogenous tumor suppressor miRNA‐34a and the chemotherapeutic agent doxorubicin (Dox) into cancer cells. The novelty of the system resides in two stimuli‐sensitive prodrugs, a matrix metalloproteinase 2 (MMP2)‐sensitive Dox conjugate and a reducing agent (glutathione, GSH)‐sensitive miRNA‐34a conjugate, self‐assembled in a single particle decorated with a polyethylene glycol corona for longevity, and a cell‐penetrating peptide (TATp) for enhanced intracellular delivery. The MMP2‐sensitivity of the system results in threefold higher cytotoxicity in MMP2‐overexpressing HT1080 cells compared to low MMP2‐expressing MCF7 cells. Cellular internalization of Dox increases by more than 70% after inclusion of TATp to the formulation. MMP2‐sensitive MM also inhibits proliferation and migration of HT1080 cells. Moreover, GSH‐sensitive MM allows for an efficient downregulation of Bcl2, survivin, and notch1 (65%, 55%, and 46%, respectively) in HT1080 cells. Combination of both conjugates in dual sensitive MM reduces HT1080 cell viability to 40% and expression of Bcl2 and survivin. Finally, 50% cell death is observed in 3D models of tumor mass. The results confirm the potential of the MM to codeliver miRNA‐34a and doxorubicin triggered by dual stimuli inherent of tumor tissues.     

A Multi-Modal Haptic Interface for Virtual Reality and Robotics

In this paper we present an innovative haptic device that combines the electro-tactile stimulation with the force and visual feedbacks in order to improve the perception of a virtual world. We discuss the sensation evoked in a user by the haptic, force, and the visual interface as provided by this device, implemented as a special glove, equipped with sensors and actuators connected to a PC. The techniques used to recreate tactile and kinesthetic sensations are based on an innovative use of cutaneous stimulation integrated with actuators and 3D modelling techniques. We discuss about the specificity of haptic interfaces, their controllers, their open problems. We present results about generating the sensation of touching virtual objects with our device. Experiments show also that, using a multi-modal sensorial pattern of stimulation, the subject perceives more realistically the virtual object. We discuss the possible use of the same technique as a way to interface intelligent robots.