Caveolin-1 and mitochondrial alterations in regenerating rat liver

The liver has a remarkable ability to regenerate after partial hepatectomy (PH), although the factors governing such ability are still poorly understood. During the prereplicative phase of the regeneration, ultrastructural alterations of periportal hepatocytes were seen, including mitochondrial swelling, abnormal accumulation of lipids, and myelin figures which could lead to the formation of lipid droplets. As it has been hypothesized that caveolin-1 is involved in lipidogenesis and in mitochondrial homeostasis, we aimed to study the subcellular distribution of caveolin-1 in hepatocytes at an early stage following PH. Liver samples were processed for light and electron microscopy at 0 h, 24 h, and 96 h after PH. The expression and subcellular distribution of caveolin-1 was assessed by immunohistochemical and immunocytochemical techniques. Following PH, at 24 h, membranes of altered mitochondria of periportal hepatocytes exhibited significant decrease of caveolin-1 expression compared with control. Myelin figures showing high expression of caveolin-1 were also seen. At 96 h, hepatocytes became ultrastructurally similar to the control liver, and the expression of caveolin-1 on mitochondria showed a moderate increase compared with 24 h after PH. Decrease of expression of caveolin-1 in the altered liver mitochondrial membranes at 24 h following PH, and the high expression of caveolin-1 observed on myelin figures, suggests involvement of caveolin-1 is in both mitochondrial homeostasis and lipidogenesis. Addressing the role played by caveolin-1 during liver regeneration might disclose additional features of mitochondrial homeostasis and lipidogenesis during frequent metabolic liver diseases.     

Quiescent and shear-induced non-isothermal crystallization of isotactic polypropylene-based nanocomposites

The paper reports a study of the effect of the addition of clay nanoparticles on melt rheology, phase structure, and non-isothermal crystallization process of isotactic polypropylene/hydrogenated oligocyclopentadiene (iPP/HOCP) system in quiescent conditions by DSC and under shear applied at different temperatures by SAXS. For both crystallization conditions, the addition of clay and/or HOCP shifts always the crystallization onset to lower values with respect to iPP. These results can be attributed to the diluent effect of HOCP that causes a decrease in the rate of nucleation and grow of the crystals, to the presence of segregated non-crystallizable phases/particles which hinder the transport of macromolecules chains toward the growing nuclei, and to the formation of beta iPP crystals and in the case of shear-induced crystallization to the presence of HPS which seems to reduce, mainly at low T _s, the amount of oriented polymer crystals, which are nuclei for the crystallization. At a given composition, the crystallization temperatures related at the crystallization under shear are always higher that those obtained by quiescent crystallization supporting the idea that the presence of extended chains in these samples act as nucleating agents favoring the crystallization process of iPP.     

Bioinspired Metal-Organic Frameworks in Mixed Matrix Membranes for Efficient Static/Dynamic Removal of Mercury from Water

The mercury removal efficiency of a novel metal-organic framework (MOF) derived from the amino acid S-methyl-L-cysteine is presented and the process is characterized by single-crystal X-ray crystallography. A feasibility study is further presented on the performance of this MOF—and also that of another MOF derived from the amino acid L-methionine—when used as the sorbent in mixed matrix membranes (MMMs). These MOF-based MMMs exhibit high efficiency and selectivity—in both static and dynamic regimes—in the removal of Hg²⁺ from aqueous environments, due to the high density of thioalkyl groups decorating MOF channels. Both MMMs are capable to reduce different concentration of the pollutant to acceptable limits for drinking water (<2 parts per billion). In addition, a novel device, consisting of the recirculation and adsorption of contaminated solutions through the MOF–MMMs, is designed and successfully explored in the selective capture of Hg²⁺. Thus, filtration of Hg²⁺ solutions with multiple passes through the permeation cell shows a gradual decrease of the pollutant concentration. These results suggest that MOF-based MMMs can be implemented in water remediation, helping to reduce either contaminants from accidental unauthorized or deliberate metal industrial dumping and to ensure access for clean and potable freshwater.     

Kinematics of a Family of Translational Parallel Mechanisms with Three 4‐DOF Legs and Rotary Actuators

This paper focuses on the kinematics of a family of translational parallel mechanisms equipped with three 4‐DOF legs and rotary actuators. The direct and the inverse position problems are solved in analytical form, the velocity analysis is carried out, the workspace is determined and the loci of both kinematic singularities and isotropic configurations are derived. Furthermore, the problem of singularity avoidance by means of actuator redundancy is addressed and some solutions are proposed. Two special architectures are finally considered as case studies: in the first, the three actuation axes are mutually orthogonal; in the second, two actuation axes are parallel to each other and the third is perpendicular to them. The comparison of the two architectures on the basis of kinematic considerations allows for the selection of the second one as a preferable solution. © 2003 Wiley Periodicals, Inc.     

SPIRE: a digital library for scientific information

In this paper we describe the architecture and implementation of a digital library framework for scientific data, particularly imagery, with a focus on support for content-based search. Content is specified by the user at one or more of the following abstraction levels: pixel, feature, and semantic. An object-definition mechanism has been developed that supports example-based and constraint-based specification of both simple and complex query targets.This framework incorporates a methodology yielding a computationally efficient implementation of image processing algorithms, thus allowing the interactive, real-time extraction and manipulation of user-specified features and content during the execution of queries. The framework is well-suited for searching scientific databases, including satellite imagery, and medical and seismic data repositories, where the richness of the information does not allow the a priori generation of exhaustive indexes.     

A survey of semantic methods in genetic programming

Several methods to incorporate semantic awareness in genetic programming have been proposed in the last few years. These methods cover fundamental parts of the evolutionary process: from the population initialization, through different ways of modifying or extending the existing genetic operators, to formal methods, until the definition of completely new genetic operators. The objectives are also distinct: from the maintenance of semantic diversity to the study of semantic locality; from the use of semantics for constructing solutions which obey certain constraints to the exploitation of the geometry of the semantic topological space aimed at defining easy-to-search fitness landscapes. All these approaches have shown, in different ways and amounts, that incorporating semantic awareness may help improving the power of genetic programming. This survey analyzes and discusses the state of the art in the field, organizing the existing methods into different categories. It restricts itself to studies where semantics is intended as the set of output values of a program on the training data, a definition that is common to a rather large set of recent contributions. It does not discuss methods for incorporating semantic information into grammar-based genetic programming or approaches based on formal methods. The objective is keeping the community updated on this interesting research track, hoping to motivate new and stimulating contributions.     

Characterization and distribution of petroleum hydrocarbons and heavy metals in groundwater from three Italian tank farms

The present paper highlights the utility of petroleum chemical fingerprinting in investigating known or suspected tank farm releases. A detailed characterization of groundwater was carried out in three tank farms located in north, central and south Italy. Eighteen parent polycyclic aromatic hydrocarbons (naphthalene through coronene), n-alkanes (n-C(10) through n-C(36)), isoprenoids pristane and phytane, vanadium, nickel and lead were determined. Distribution profiles and diagnostic ratios of specific fuel constituents were studied in order to identify contamination sources. Data analysis shows that in the study sites multiple pollutant sources affecting the tank farms and the surrounding industrial areas are present. Both high concentrations of contaminants coming from fuel releases and noticeable concentrations of biogenic compounds were found. A detailed data analysis suggests the origin and the level of pollution of the three sites. The results demonstrate that threshold concentration approach is not always sufficient and it is necessary to carry out studies of contaminant distribution and their diagnostic ratios in order to perform a successful forensic investigation.     

Assessment of thermal behaviour of thermo-active diaphragm walls based on monitoring data

Thermo-active diaphragm walls have proved their effectiveness in the thermal conditioning of buildings and infrastructures. However, some aspects still need to be investigated in order to tailor methods and tools for an accurate prediction of their energy and structural performance. In this perspective, some issues are addressed that concern the definition of models for the numerical analysis, in particular issues about the modelling of geometry and thermal boundary conditions. Taking advantage of a monitoring programme on a real full-scale structure, this research focuses on the assessment of heat transfer process and thermal response of diaphragm wall and soil mass on the basis of field data. Understanding of the heat transfer process contributes to the definition of the time-dependent thermal boundary conditions at the excavation side. From the analysis of thermal gradients in the wall, the condition at the excavation side is recognised as a major factor that influences the heat transfer process, governing the direction of the heat flux in different seasons of operation of the geothermal system.