Design of global tracking controllers for flexible-joint robots

An approach to design control laws for trajectory tracking of robots having flexible joints is presented. An application to the adaptive control is also given with reference to a single-link robot with one revolute elastic joint whose parameters are unknown.     

Skin permeation of 5-methoxypsoralen from topical dosage forms

The topical photochemotherapy of dermatoses with psoralens (PUVA therapy) requires an adequate drug level at the target site (basal epidermis) at the time of UVA radiation. The aim of this work was to enhance 5-methoxypsoralen transport to the basal epidermis, with the goal to shorten the delay between drug application and UVA irradiation. 5-Methoxypsoralen transport through rabbit skin was studied in vitro from topical formulations (water solution, gel, and emulsion). The results obtained show that the use of the emulsion increased the flux through rabbit ear skin, even if partitioning was not favorable. Additionally, the time lag was sensibly reduced, compared with the gel and solution. Furthermore, drug accumulation in human skin in vitro was determined using the thin slicing technique. Human skin accumulation profile was significantly higher for the emulsion, compared with the gel, indicating that the delay between psoralen application and UVA irradiation can be shortened.     

Hamiltonian description and dynamic control of flexible robots

The article is concerned with the problem of modeling and control of flexible robots. This problem is faced by using the Hamiltonian approach and the assumed modes method to obtain an approximate finite dimensional model of the robot dynamics. The pseudo-linearization method is then applied to design a nonlinear control law that is effective in the neighborhood of the operating points. The article ends with an application to a single-link robot arm.     

How does the application of an IT service innovation affect firm performance? A theoretical framework and empirical analysis on e-commerce

Understanding the effects of IT-related innovations on firm performance is crucial for businesses. Extant research has investigated the implications of IT innovations and provided some important findings, but the varied theoretical approaches have produced results that are often ambiguous: thus there is a need to examine the process further. We attempted to provide a systematic, theoretically informed framework for understanding the conditions that may enhance (or hinder) the potential of IT innovations in a sample of firms. Our model included business and IT resources, both internal and external, that may influence the performance of firms which have applied a pervasive IT service innovation: e-commerce. Our empirical test of the model used a research design that takes into account time-lag effects. The model explained more than half of the variance in the performance of IT innovators and offered several explanations for why some firms succeeded in implementing IT service innovations while others did not. Several theoretical and managerial implications result from these findings.     

Multiple Roles for Cytokines in Atopic Dermatitis: From Pathogenic Mediators to Endotype-Specific Biomarkers to Therapeutic Targets

Atopic dermatitis (AD) is one of the most common chronic inflammatory skin diseases, which generally presents with intense itching and recurrent eczematous lesions. AD affects up to 20% of children and 10% of adults in high-income countries. The prevalence and incidence of AD have increased in recent years. The onset of AD mostly occurs in childhood, although in some cases AD may persist in adult life or even manifest in middle age (adult-onset AD). AD pathophysiology is made of a complex net, in which genetic background, skin barrier dysfunction, innate and adaptive immune responses, as well as itch contribute to disease development, progression, and chronicization. One of the most important features of AD is skin dehydration, which is mainly caused by filaggrin mutations that determine trans-epidermal water loss, pH alterations, and antigen penetration. In accordance with the “outside-inside” theory of AD pathogenesis, in a context of an altered epidermal barrier, antigens encounter epidermal antigen presentation cells (APCs), such as epidermal Langerhans cells and inflammatory epidermal dendritic cells, leading to their maturation and Th-2 cell-mediated inflammation. APCs also bear trimeric high-affinity receptors for immunoglobulin E (IgE), which induce IgE-mediated sensitizations as part of pathogenic mechanisms leading to AD. In this review, we discuss the role of cytokines in the pathogenesis of AD, considering patients with various clinical AD phenotypes. Moreover, we describe the cytokine patterns in patients with AD at different phases of the disease evolution, as well as in relation to different phenotypes/endotypes, including age, race, and intrinsic/extrinsic subtypes. We also discuss the outcomes of current biologics for AD, which corroborate the presence of multiple cytokine axes involved in the background of AD. A deep insight into the correlation between cytokine patterns and the related clinical forms of AD is a crucial step towards increasingly personalized, and therefore more efficient therapy.     

Engineering Natural Pollen Grains as Multifunctional 3D Printing Materials

The development of multifunctional 3D printing materials from sustainable natural resources is a high priority in additive manufacturing. Using an eco-friendly method to transform hard pollen grains into stimulus-responsive microgel particles, we engineered a pollen-derived microgel suspension that can serve as a functional reinforcement for composite hydrogel inks and as a supporting matrix for versatile freeform 3D printing systems. The pollen microgel particles enabled the printing of composite inks and improved the mechanical and physiological stabilities of alginate and hyaluronic acid hydrogel scaffolds for 3D cell culture applications. Moreover, the particles endowed the inks with stimulus-responsive controlled release properties. The suitability of the pollen microgel suspension as a supporting matrix for freeform 3D printing of alginate and silicone rubber inks was demonstrated and optimized by tuning the rheological properties of the microgel. Compared with other classes of natural materials, pollen grains have several compelling features, including natural abundance, renewability, affordability, processing ease, monodispersity, and tunable rheological features, which make them attractive candidates to engineer advanced materials for 3D printing applications.     

Sexual Harassment Under Social Identity Threat: The Computer Harassment Paradigm.

Two laboratory experiments investigated the hypothesis that threat to male identity would increase the likelihood of gender harassment. In both experiments, using the computer harassment paradigm, male university students (N=80 in Experiment 1, N=90 in Experiment 2) were exposed to different types of identity threat (legitimacy threat and threat to group value in Experiment 1 and distinctiveness threat and prototypicality threat in Experiment 2) or to no threat and were then given the opportunity to send pornographic material to a virtual female interaction partner. Results show that (a) participants harassed the female interaction partner more when they were exposed to a legitimacy, distinctiveness, or prototypicality threat than to no threat; (b) this was mainly true for highly identified males; and (c) harassment enhanced postexperimental gender identification. Results are interpreted as supporting a social identity account of gender harassment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A multi-objective evolutionary approach to the protein structure prediction problem

The protein structure prediction (PSP) problem is concerned with the prediction of the folded, native, tertiary structure of a protein given its sequence of amino acids. It is a challenging and computationally open problem, as proven by the numerous methodological attempts and the research effort applied to it in the last few years. The potential energy functions used in the literature to evaluate the conformation of a protein are based on the calculations of two different interaction energies: local (bond atoms) and non-local (non-bond atoms). In this paper, we show experimentally that those types of interactions are in conflict, and do so by using the potential energy function Chemistry at HARvard Macromolecular Mechanics. A multi-objective formulation of the PSP problem is introduced and its applicability studied. We use a multi-objective evolutionary algorithm as a search procedure for exploring the conformational space of the PSP problem.     

Computational energy-based redesign of robust proteins

The robustness of a system is a property that pervades all aspects of Nature. The ability of a system to adapt itself to perturbations due to internal and external agents, to aging, to wear, to environmental changes is one of the driving forces of evolution. At the molecular level, understanding the robustness of a protein has a great impact on the in silicon design of polypeptide chains and drugs; the chance of computationally checking the ability of a protein to preserve its structure and function in the native state can lead to the design of new compounds that can work in a living cell more effectively. Inspired by the well known robustness analysis framework used in Electronic Design Automation, we introduced a notion of robustness for proteins and two dimensionless quantities: the energetic yield and the energetic relative entropy. We used the energetic yield in order to quantify the robustness of a protein, and to detect sensitive regions and sensitive residues in the protein, whereas we adopted the energetic relative entropy to measure the discrepancy between two potential energy distributions. Subsequently, we implemented a new robustness-centred protein design algorithm called Robust-Protein-Design (RPD); the aim of the algorithm is to discover new conformations with a specific function with high yield values. We performed an extensive characterization of the robustness property of many peptides, proteins, and drugs. Moreover, we found that robustness and relative entropy are conflicting objectives which constitute a trade-off useful as design principle for new proteins and drugs.Finally, we used the RPD algorithm on the Crambin protein (1CRN); the obtained results confirm that the algorithm was able to find out a Crambin-like protein that is 23% more robust than the wild type.