Surveillance after colorectal cancer surgery

Early diagnosis of local and distant recurrences of colorectal cancer remains difficult and there is no agreement on the effectiveness of follow-up in these patients. The aim of this study is to assess the value of our method of follow-up. We consider 239 patients with colorectal cancer and at least 2 years follow-up following radical resection. A local recurrence appeared in 26 patients (10.9%), a distant metastasis in 41 (17.1%), while in seven (2.9%) local and distant recurrences appeared simultaneously. Local recurrence was detected because of an increase in carcinoembryonic antigen (CEA) level in 15 patients (57.7%), during a scheduled endoscopy in four (15.4%) and because of symptoms in seven (26.9%). In seven patients (26.9%) a radical resection was possible. Distant metastases were detected by CEA levels in 20 patients (48.8%), by ultrasonography (U.S.) in 12 (29.3%) and by chest X-ray in five (12.2%). In 13 of 26 patients with liver metastases a resection was performed. This study shows that few patients benefit from follow-up and only CEA levels and liver U.S. performed intensively between 15 and 36 months after surgery are useful in early detection of recurrences. A modification of the follow-up to the single patient, according to the stage, location and grading of cancer, could improve the results, so lowering the costs of this expensive practice.     

Selective interactions among the multiple connexin proteins expressed in the vertebrate lens: the second extracellular domain is a determinant of compatibility between connexins

Gap junctions are collections of intercellular channels composed of structural proteins called connexins (Cx). We have examined the functional interactions of the three rodent connexins present in the lens, Cx43, Cx46, and Cx50, by expressing them in paired Xenopus oocytes. Homotypic channels containing Cx43, Cx46, or Cx50 all developed high conductance. heterotypic channels composed of Cx46 paired with either Cx43 or Cx50 were also well coupled, whereas Cx50 did not form functional channels with Cx43. We also examined the functional response of homotypic and heterotypic channels to transjunctional voltage and cytoplasmic acidification. We show that all lens connexins exhibited sensitivity to cytoplasmic acidification as well as to voltage, and that voltage-dependent closure of heterotypic channels for a given connexin was dramatically influenced by its partner connexins in the adjacent cell. Based on the observation that Cx43 can discriminate between Cx46 and Cx50, we investigated the molecular determinants that specify compatibility by constructing chimeric connexins from portions of Cx46 and Cx50 and testing them for their ability to form channels with Cx43. When the second extracellular (E2) domain in Cx46 was replaced with the E2 of Cx50, the resulting chimera could no longer form heterotypic channels with Cx43. A reciprocal chimera, where the E2 of Cx46 was inserted into Cx50, acquired the ability to functionally interact with Cx43. Together, these results demonstrate that formation of intercellular channels is a selective process dependent on the identity of the connexins expressed in adjacent cells, and that the second extracellular domain is a determinant of heterotypic compatibility between connexins.     

The role of spectral resolution and classifier complexity in the analysis of hyperspectral images of forest areas

Remote sensing hyperspectral sensors are important and powerful instruments for addressing classification problems in complex forest scenarios, as they allow one a detailed characterization of the spectral behavior of the considered information classes. However, the processing of hyperspectral data is particularly complex both from a theoretical viewpoint [e.g. problems related to the Hughes phenomenon (Hughes, 1968) and from a computational perspective. Despite many previous investigations that have been presented in the literature on feature reduction and feature extraction in hyperspectral data, only a few studies have analyzed the role of spectral resolution on the classification accuracy in different application domains. In this paper, we present an empirical study aimed at understanding the relationship among spectral resolution, classifier complexity, and classification accuracy obtained with hyperspectral sensors for the classification of forest areas. We considered two different test sets characterized by images acquired by an AISA Eagle sensor over 126 bands with a spectral resolution of 4.6 nm, and we subsequently degraded its spectral resolution to 9.2, 13.8, 18.4, 23, 27.6, 32.2 and 36.8 nm. A series of classification experiments were carried out with bands at each of the degraded spectral resolutions, and bands selected with a feature selection algorithm at the highest spectral resolution (4.6 nm). The classification experiments were carried out with three different classifiers: Support Vector Machine, Gaussian Maximum Likelihood with Leave-One-Out-Covariance estimator, and Linear Discriminant Analysis. From the experimental results, important conclusions can be made about the choice of the spectral resolution of hyperspectral sensors as applied to forest areas, also in relation to the complexity of the adopted classification methodology. The outcome of these experiments are also applicable in terms of directing the user towards a more efficient use of the current instruments (e.g. programming of the spectral channels to be acquired) and classification techniques in forest applications, as well as in the design of future hyperspectral sensors.     

Functional Redesign of Mantis 2.0, a Hybrid Leg-Wheel Robot for Surveillance and Inspection

The paper discusses the redesign of the second version of the Mantis hybrid leg-wheel mobile robot, conceived for surveillance and inspection tasks in unstructured indoor and outdoor environments. This small-scale ground mobile robot is characterized by a main body equipped with two front actuated wheels, a passive rear axle and two rotating legs. Motion on flat and even ground is purely wheeled in order to obtain high speed, high energetic efficiency and stable camera vision; only in case of obstacles or ground irregularities the front legs realize a mixed leg-wheel locomotion to increase the robot climbing ability; in particular, the outer profile of the legs, inspired by the praying mantis, is specially designed to climb square steps. The multibody simulations and the experimental tests on the first prototype have shown the effectiveness of the mixed leg-wheel locomotion not only for step climbing, but also on uneven and yielding terrains. Nevertheless, extensive experimental tests have shown that the front wheels may slip in the last phase of step climbing in case of contact with some materials. In order to overcome this problem, the leg design has been modified with the introduction of auxiliary passive wheels, which reduce friction between legs and step upper surface; these wheels are connected to the legs by one-way bearings, in order to rotate only when they are pulled by the front wheels, and remaining locked when they have to push forward the robot. The influence of the auxiliary wheels on the front wheels slippage is investigated by means of theoretical analysis and multibody simulations.     

A genetic expectation-maximization method for unsupervised change detection in multitemporal SAR imagery

In this paper, we present a novel, automatic and unsupervised change-detection approach to the analysis of single-channel single-polarization multitemporal SAR images. The statistical parameters of the changed and unchanged classes, which are assumed to follow a generalized Gaussian (GG) distribution in the analysed log-ratio image, are explicitly estimated by the expectation-maximization (EM) algorithm initialized with a robust strategy based on genetic algorithms (GAs). In addition, the proposed approach integrates two further processing capabilities. The first one intends to cope with the problem of the automatic detection of multiple changes in the scene. This is carried out by modelling the log-ratio image histogram with a multimodal GG mixture whose number of components is estimated basing on the Bayesian information criterion (BIC). The second processing capability allows exploitation of spatial contextual information in the change detection process through a Markovian formulation. Results obtained on both simulated and real data are reported and discussed.     

The Industrial Heritage and the New Architecture： Teaching, Researching, Designing the Place Identity

The new architecture may provide unusual opportunities for the abandoned areas involved by former industrial processes, both in the city centers and in the landscape. In fact, it may create new centralities and give new collective function for deprived areas. The case study of the architectural and educational project for a new museum park devoted to the technique and the science in the Apennine＇ s landscape near Parma （Italy） may give an interesting point of view about the role of the teaching and the research of the architecture in the former industrial heritage, and to avoid the abandonment and the pauperization of the territory around.     

Physical Reasoning to Synchronize Electrical Signals and Related Diagnostics in Plasma Focus Devices

Plasma Focus (PF) devices as well as other similar pulsed discharge devices requires a variety of diagnostics for their proper control and optimization, including the voltage between electrodes, the time derivative of the discharge current, detection of X-rays and neutron emissions, and pulsed laser images (Shadow, Schlieren, interferograms). This article discusses the problem of the time reference of all these outputs and proposes specific techniques for synchronizing them based on sound physical grounds. The foundations of synchronization criterion are verified in several experiments on PF devices.     

Compensation of birefringence in lead‐free polarizing beam splitters for LCOS projectors

Abstract— Most optical designs for delivering light to LCOS imagers and then from the imagers to the projection lens use polarizing‐beam‐splitter (PBS) technology. Most of the PBSs used in commercial LCOS projectors contain glass with a significant amount of lead (Pb). Such glasses have inherently low stress birefringence, and therefore maintain the polarization state of light passing through them. However, Pb‐bearing glass is an expensive, difficult to process, and hazardous material with special disposal requirements and is therefore not desirable in consumer‐electronic products. On the other hand, Pb‐free wire‐grid plate PBSs require a longer back focal length than would be optimal. Data and modeling results show that uniform high‐contrast dark states may be obtained from lead‐free‐glass Cartesian PBS prisms when a quarter‐wave compensator is used between the imager and the PBS.