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Hydrogels that can respond to a number of external stimuli and at the same time show impressive rheological properties are promising materials for a wide range of bioapplications. Here, we present a series of well-defined linear amphiphilic pentablock hybrid polypeptides of the ABCBA type, where A is poly(l-lysine), B is poly(l-histidine)-co-poly(γ-benzyl-l-glutamate), and C is poly(ethylene oxide) (PEO). The polymers were synthesized by the sequential primary amine ring-opening polymerization of N-carboxy anhydrides using bis amine poly(ethylene oxide) (PEO) as a bifunctional macroinitiator, and the length of all of the blocks was varied. The resulting materials formed novel extrudable in situ forming quickly self-healing hydrogels, responsive to the alteration of pH and increase of temperature. The connection between the alteration of the secondary structure of the polypeptides with the viscoelastic behavior was revealed by means of rheology and circular dichroism. Small-angle neutron scattering and scanning electron microscopy were employed to shed light on the structure of the polymers and how it affects their rheological properties. The obtained polymers were subjected to enzymatic degradation tests with trypsin and leucine aminopeptidase. The results suggest that these biomaterials have the potential to be used in a number of bioapplications like drug delivery, 3D printing, and tissue engineering. © 2021 American Chemical Society.

DOI: 10.1364/OME.7.000844 URL: https://www.osapublishing.org/ome/abstract.cfm?uri=ome-7-3-844 Filiació URV: SI Memòria We report on a detailed comparative study of the spectroscopic and thermo-optic properties of tetragonal Tm:LiLnF4 (Ln = Y, Gd, and Lu) crystals indicating their suitability for highly-efficient microchip lasers diode-pumped at ~791 nm and operating at ~1.91 ¿m. An a-cut 8 at.% Tm:LiYF4 micro-laser generated 3.1 W of linearly polarized output at 1904 nm with a slope efficiency of ¿ = 72% and a laser threshold of only 0.24 W. The internal loss for this crystal is as low as 0.0011 cm-1. For 8 at.% Tm:LiGdF4 and 12 at.% Tm:LiLuF4 lasers, the output power reached ~2 W and ¿ was 65% and 52%, respectively. The thermal lens in all Tm:LiLnF4 crystals is weak, positive and low-astigmatic. The potential for the Tm:LiLnF4 lasers to operate beyond ~2 ¿m due to a vibronic coupling has been proved. The Tm:LiYF4 vibronic laser generated 375 mW at 2026-2044 nm with ¿ = 31%. The Tm:LiLnF4 crystals are very promising for passively Q-switched microchip lasers.

A Reinforcement Learning Model of Reaching Integrating Kinematic and Dynamic Control in a Simulated Arm Robot.

The paper investigates the Italian debate on municipalization between the 1880s and the 1920s and is divided in two parts. The first deals with the emrgence of municipalization in the late nineteenth century as a component in the birth of the Social State. The second part concerns the anlytical tools elaborated by some leading Italian economists in the first three decades of the twentieth century, with an early expanding stage (until World War I) and a later stage (under Fascism) of prevalent stagnation.

Recent evidence shows that perceiving objects automatically activates the representation of their affordances. For example, the experiments on compatibility effects show that the reaction time needed to categorise an object by producing a certain hand grip is faster if the requested response is compatible with the affordance elicited by the size of the object (e.g., a small or a large grip). The article presents a neural-network architecture that provides a general framework to account for this kind of effects. The model was designed with a methodological approach that aims to provide increasingly general accounts of brain and behaviour (the approach uses four sources of constraints: neuroscientific data, behavioural data, functioning within embodied systems, and reproduction of learning processes). The model is based on four principles of brain organisation that underlie most compatibility effects. First, visual perception and action are organised in the brain along a dorsal neural pathway, which encodes affordances, and a ventral pathway, which encodes goals. Second, the prefrontal cortex within the ventral pathway gives a top-down bias to action selection by integrating information on stimuli, context, and goals. Third, reaction times depend on dynamic neural competitions for action selection, which integrate bottom-up and top-down sources of information. The congruence/incongruence between the information related to affordances and current goals explains the different reaction times found in the experiments. Fourth, because words referring to objects trigger "internal simulations" of their referents, they can cause compatibility effects similarly to objects. We validated the model by reproducing and explaining three types of compatibility effects and showed its heuristic power by producing two testable predictions. We also assessed the explicative power of the model on the basis of a critical comparison with related models and showed how it could be extended to account for other compatibility effects by relying on the aforementioned four principles.

Background Osteoporotic vertebral fractures (VFs) often go unrecognised in both healthy individuals and in pathological conditions. Few data exist on VFs in patients hospitalised in Internal Medicine Units (IMUs), who often suffer from multiple concomitant chronic disorders. Aim of the study This multicentre cross-sectional study was aimed at assessing the prevalence of VFs in an unselected population of patients referring to IMUs. Correlations between VFs and the main coexisting diseases were also investigated. Methods Information on demographic, clinical and laboratory findings, and on the presence of known risk factors for osteoporosis was recorded. The Genant's semi-quantitative method was used to evaluate, in a central reading centre, the presence and severity of VFs in the thoracic and lumbar spine. Results A cohort of 995 patients was evaluated. At least one VF of any grade was found in 47.5% of patients, with similar prevalence between females (48.1%) and males (46.7%). Older age, chronic obstructive pulmonary disease, and previous diagnosis of osteoporosis showed a significant association with VFs in multivariable analysis. However, 79.7% of the VFs were observed in patients without previous diagnosis of osteoporosis. Moreover, a VF of grade 2 or greater was found in 20.8% of patients. Conclusions Fragility VFs is a very frequent finding in patients hospitalised in IMUs. Consequently, more attention should be devoted in this clinical setting to this comorbidity, which is known to be an additional factor for mortality and, when localised in the thoracic part of the spine, may negatively influence a concomitant respiratory insufficiency.

Background: Traditionally, pneumonia has been classified as either community- or hospital-acquired. Although only limited data are available, health care–associated pneumonia has been recently proposed as a new category of respiratory infection. “Health care–associated pneumonia” refers to pneumonia in patients who have recently been hospitalized, had hemodialysis, or received intravenous chemotherapy or reside in a nursing home or long-term care facility. Objective: To ascertain the epidemiology and outcome of community-acquired, health care–associated, and hospital-acquired pneumonia in adults hospitalized in internal medicine wards. Design: Multicenter, prospective observational study. Setting: 55 hospitals in Italy comprising 1941 beds. Patients: 362 patients hospitalized with pneumonia during two 1-week surveillance periods. Measurements: Cases of radiologically and clinically assessed pneumonia were classified as community-acquired, health care–associated, or hospital-acquired and rates were compared. Results: Of the 362 patients, 61.6% had community-acquired pneumonia, 24.9% had health care–associated pneumonia, and 13.5% had hospital-acquired pneumonia. Patients with health care–associated pneumonia had higher mean Sequential Organ Failure Assessment scores than did those with community-acquired pneumonia (3.0 vs. 2.0), were more frequently malnourished (11.1% vs. 4.5%, and had more frequent bilateral (34.4% vs. 19.7%) and multilobar (27.8% vs. 21.5%) involvement on a chest radiograph. Patients with health care–associated pneumonia also had higher fatality rates (17.8% [CI, 10.6% to 24.9%] vs. 6.7% [CI, 2.9% to 10.5%]) and longer mean hospital stay (18.7 days [CI, 15.9 to 21.5 days] vs. 14.7 days [CI, 13.4 to 15.9 days]). Logistic regression analysis revealed that depression of consciousness (odds ratio [OR], 3.2 [CI, 1.06 to 9.8]), leukopenia (OR, 6.2 [CI, 1.01 to 37.6]), and receipt of empirical antibiotic therapy not recommended by international guidelines (OR, 6.4 [CI, 2.3 to 17.6]) were independently associated with increased intrahospital mortality. Limitations: The number of patients with health care–associated pneumonia was relatively small. Microbiological investigations were not always homogeneous. The study included only patients with pneumonia that required hospitalization; results may not apply to patients treated as outpatients. Conclusion: Health care–associated pneumonia should be considered a distinct subset of pneumonia associated with more severe disease, longer hospital stay, and higher mortality rates. Physicians should differentiate between patients with health care–associated pneumonia and those with community-acquired pneumonia and provide more appropriate initial antibiotic therapy.

We simulated organisms with an arm terminating with a hand composed by two fingers, a thumb and an index, each composed by two segments, whose behavior was guided by a nervous system simulated through an artificial network. The organisms, which evolved through a genetic algorithm, lived in a bidimensional environment containing four objects, either large or small, either grey or black. In a baseline simulation the organisms had to learn to grasp small objects with a precision grip and large objects with a power grip. In Simulation 1 the organisms learned to perform two tasks: in Task 1 they continued to grasp objects according to their size, in Task 2 they had to decide the objects' color by using a precision or a power grip. Learning occured earlier when the grip required to respond to the object and to decide the color was the same than when it was not, even if object size was irrelevant for the task. The simulation replicates the result of an experiment by Tucker & Ellis (2001) suggesting that seeing objects automatically activates motor information on how to grasp them.

Mirror neurons may play a role in representing not only signs but also their meaning. Since actions are the only aspect of behavior which is inter-individually accessible, interpreting meanings in terms of actions might explain how meanings can be shared. Behavioral evidence and Artificial Life simulations suggest that seeing objects or processing words referring to objects automatically activates motor actions.

We describe simulations of groups of agents that have to reach a target in a two dimensional environment, the performance criterion being the time taken by the last agent to reach the target. If the target is within a given distance from the agent, the agent moves towards the target; otherwise it moves randomly. The simulations contrast groups with and without a leader, where a leader is a member of the group which other members of the group follow as it moves through the environment. We investigate three factors that affect group performance: (1) group size; (2) the presence or absence of an individual agent with the ability to detect targets at a greater distance than those 'visible' to its companions; (3) the existence of a communication network among group members. The results show that, in groups without communication, leaders have a beneficial effect on group performance, especially in large groups and if the individual with better than average sensory capabilities is the leader of the group. However, in situations where group members can communicate, these results are reversed, with leaders being detrimental, rather than beneficial, to group performance