Mechanical pulling of linked ring polymers: Elastic response and link localisation

By using Langevin dynamics simulations, we study how semiflexible rings that are topologically linked respond tomechanical stretching.We use both constant-force and constant-velocity pulling protocols and map out how the mechanical tension affects observables related to metric quantities such as the longitudinal extension or span, and topology-related ones such as the length of the linked portion. We find that the average extension of linked rings, once divided by that of a single equivalent ring, is nonmonotonic in the applied force. We show that this remarkable feature becomes more prominent as the link complexity is increased, and originates from the different stretching compliance of the linked portion and the rest of the rings' contour. By comparing the results of different pulling protocols, we also establish the best one for telling apart different types of links from their tensile response

It does not occur by chance: a mediation model of the influence of workers' characteristics, work environment factors, and near misses on agricultural machinery-related accidents

Agriculture is among the most hazardous productive sectors, and farm machinery is a major source of injury. In the present study, a mediated model was used to test the role played by workers’ characteristics, work environment factors, and near misses in predicting agricultural machinery-related accidents in a sample of Italian users (n = 290). Hours worked per week (via the mediation of an adverse work environment) showed a positive association and years of work experience (via the mediation of risk perception) showed a negative association with the probability of being involved in a near miss, which in turn showed a positive association with the probability of being involved in a machinery-related accident. Implications for tailored preventive interventions are discussed

Falls From Agricultural Machinery: Risk Factors Related to Work Experience, Worked Hours, and Operators' Behavior

Objective: We investigated the risk factors for falls when egressing from agricultural tractors, analyzing the role played by worked hours, work experience, operators' behavior, and near misses. Background: Many accidents occur within the agricultural sector each year. Among them, falls while dismounting the tractor represent a major source of injuries. Previous studies pointed out frequent hazardous movements and incorrect behaviors adopted by operators to exit the tractor cab. However, less is known about the determinants of such behaviors. In addition, near misses are known to be important predictors of accidents, but they have been under-investigated in the agricultural sector in general and as concerns falls in particular. Method: A questionnaire assessing dismounting behaviors, previous accidents and near misses, and participants' relation with work was administered to a sample of Italian tractor operators (n = 286). Results: A mediated model showed that worked hours increase unsafe behaviors, whereas work experience decreases them. Unsafe behaviors in turn show a positive association with accidents, via the mediation of near misses. Conclusions: We gave a novel contribution to the knowledge of the chain of events leading to fall accidents in the agricultural sector, which is one of the most hazardous industries. Applications: Besides tractor design improvements, preventive training interventions may focus on the redesign of the actual working strategies and the adoption of engaging training methods in the use of machinery to optimize the learning of safety practices and safe behavior

Reconstructing the Density of States by History-Dependent Metadynamics

We present a novel method for the calculation of the energy density of states D(E) for systems described by classical statistical mechanics. The method builds on an extension of a recently proposed strategy that allows the free energy profile of a canonical system to be recovered within a pre-assigned accuracy,[A. Laio and M. Parrinello, PNAS 2002]. The method allows a good control over the error on the recovered system entropy. This fact is exploited to obtain D(E) more efficiently by combining measurements at different temperatures. The accuracy and efficiency of the method are tested for the two-dimensional Ising model (up to size 50x50) by comparison with both exact results and previous studies. This method is a general one and should be applicable to more realistic model systems

Synthesis of thia-Michael-Type Adducts between Naphthoquinones and N-Acetyl-L-Cysteine and Their Biological Activity

A series of naphthoquinones, namely, 1,4-naphthoquinone, menadione, plumbagin, juglone, naphthazarin, and lawsone, were reacted with N-acetyl-L-cysteine, and except for lawsone, which did not react, the related adducts were obtained. After the tuning of the solvent and reaction conditions, the reaction products were isolated as almost pure from the complex reaction mixture via simple filtration and were fully characterized. Therefore, the aim of this work was to evaluate whether the antitumor activity of new compounds of 1,4-naphthoquinone derivatives leads to an increase in ROS in tumor cell lines of cervical carcinoma (HeLa), neuroblastoma (SH-SY5Y), and osteosarcoma (SaOS2, U2OS) and in normal dermal fibroblast (HDFa). The MTT assay was used to assay cell viability, the DCF-DA fluorescent probe to evaluate ROS induction, and cell-cycle analysis to measure the antiproliferative effect. Compounds 8, 9, and 12 showed a certain degree of cytotoxicity towards all the malignant cell lines tested, while compound 11 showed biological activity at higher IC50 values. Compounds 8 and 11 induced increases in ROS generation after 1 h of exposure, while after 48 h of treatment, only 8 induced an increase in ROS formation in HeLa cells. Cell-cycle analysis showed that compound 8 caused an increase in the number of G0/G1-phase cells in the HeLa experiment, while for the U2OS and SH-SY5Y cell lines, it led to an accumulation of S-phase cells. Therefore, these novel 1,4-naphthoquinone derivatives may be useful as antitumoral agents in the treatment of different cancers

Teaching and learning human Anatomy in the University of Pavia: from models and clinical specimens to prosection on 3D models from our museum collection

Due to decline of resources and support for teaching human anatomy, in our Institute the use of cadaver dissection is not economically feasible. After a few years in which I was able to perform prosection on fixed organs belonging to the Institute collection, over the last years students learned topographical anatomy on commercial plastic models (bones, muscles, joints, trunks and brains). New perspectives recently occurred thanks to a collaboration with Prof. Auricchio’s group, which is involved in the strategic plan “3DPRINTING” (http://www. unipv.eu/site/home/area-stampa/articolo12952.html). First, we have segmented DICOM images of Computed Tomography (CT) to reconstruct 3D models of all the feet’s bones from a patient. Then, these 3D models have been post-processed to obtain suitable file for 3D printing. A 3DSYSTEMS ProJet 460 Plus, professional, full-color binder jetting printer (property of General Surgery2), has been used to create 3D models of feet’s bone by chalk powder binding. Medical students will use these models to test their own ability to recognize feet’s bones shape and to recompose them. Second, a plastic 3D anatomical model has been scanned by Artec Eva 3D Object Scanner to obtain a 3D virtual model of the physical one; this model has been modified to create a new modular model, printed with a process similar to one described above. Our Anatomy Institute is enriched by a Museum, established in the late eighteenth century by universally known anatomists (Rezia, Scarpa, Panizza, Zoja). This historical collection contains several sections (osteology, angiology, splanchnology, neurology and topographic anatomy). It is impossible to use these anatomical specimens of historical interest for prosection, but their life-size copies will constitute a cheap and effective method of learning. This strategy could not replace cadaver dissection experience but we hope that it could assist students in the comprehension of anatomical systems in a cost effective way within a systemic anatomy course. Besides, this method should optimize specimen’s choice and focalize student’s attention on peculiar, selected samples, preparing more appropriately medical students to their clinical practice

MIRTO: an open-source robotic platform for education

This paper introduces the MIddlesex RoboTic platfOrm (MIRTO), an open-source platform that has been used for teaching First Year Computer Science students since the academic year 2013/2014, with the aim of providing a physical manifestation of Software Engineering concepts that are often delivered using only abstract or synthetic case studies. In this paper we provide a detailed description of the platform, whose hardware specifications and software libraries are all released open source; we describe a number of teaching usages of the platform, report students’ projects, and evaluate some of its aspects in terms of effectiveness, usability, and maintenance

Estudo da adição de pitaya na produção de cerveja / Study of pitaya addition in beer production

Cerveja é a bebida obtida pela fermentação alcoólica do mosto cervejeiro oriundo do malte de cevada e água potável, por ação de levedura, com adição de lúpulo. A bebida encontra-se dentre umas das mais populares, cuja produção vem de milhares de anos e desde então tem sofrido aprimoramento técnico o que contribui com a qualidade. A buscar por novas tecnologias que otimizem a produtividade e melhorem a qualidade do produto final, bem como, a exploração de outros ingredientes vem crescendo. As microcervejarias produzem cervejas com alto valor agregado utilizando processos de fabricação e ingredientes diferentes das de larga escala. Dentre os ingredientes utilizados em cervejas artesanais, encontram-se os diferentes tipos de frutas, nesse sentido a pitaya de polpa vermelha é uma alternativa a ser explorada, pois, possui características atraentes, como alto teor de compostos fenólicos e substâncias com atividade antioxidante, como o ácido ascórbico, carotenóides e polifenóis, além de conter betalaínas, o que leva a um efeito benéfico à saúde e contribui com a tonalidade da cerveja. Este trabalho teve como objetivo avaliar a possibilidade da adição da fruta de pitaya de polpa vermelha como ingrediente na fabricação de cerveja. Foram feitos tratamentos com a adição de pitaya em diferentes concentrações e métodos de adição. A cerveja produzida foi caracterizada em relação aos compostos fenólicos, pH, acidez, sólidos totais, teor alcoólico e cor. A adição da fruta de pitaya, de polpa vermelha, na produção de cervejas estilo “fruitbier” é uma alternativa para a diversificação da ofertas de cervejas especiais. Neste estudo, a pitaya contribui com características desejáveis na cerveja, especialmente a cor e uma maior concentração de fenólicos totais, não comprometendo outras características importantes da cerveja ou interferindo negativamente no processo

Elaboração de cerveja com adição de alcachofra / Brewing with addition of artichoke

A cerveja é uma das bebidas mais consumidas no mundo, constituída basicamente de malte, lúpulo, fermento e água. No entanto, o ramo das cervejas artesanais tem apresentado grande crescimento nos últimos anos, o que é bem positivo, já que a proposta é trazer cervejas com alta qualidade, apresentando novas combinações para a obtenção de diferentes tipos de cerveja dentro de seus vários estilos. Muitas vezes são adicionadas frutas ou ervas, com objetivo de obter um produto inovador, esses ingredientes podem contribuir em diversos aspectos, como: amargor, cor, teor alcoólico, sabor, entre outros. A alcachofra (Cynara scolymus) é uma planta utilizada na culinária e apresenta diversas aplicações medicinais, como no tratamento de diabetes, doenças de pele, também é um agente antiesclerótico, hepatoestimulante, diurético e colagoga. Os principais componentes da folha de alcachofra são: os ácidos cafeoilquínicos, flavonoides, sesquiterpenos e ácidos alifáticos. Assim, o objetivo desse trabalho foi produzir uma cerveja com adição de alcachofra. O experimento consistiu em adicionar diferentes concentrações de infusão das folhas desidratadas de alcachofra: 1; 2 e 3 gramas de folhas desidratadas/litro de cerveja, além do tratamento controle. A adição de alcachofra provocou alterações nas características da cerveja, entretanto, não interferiu no processo fermentativo. A alcachofra tem potencial para ser utilizada em formulações de cervejas, contribuindo com a diversificação da oferta de cervejas especiais e com o desenvolvimento do setor, especialmente das microcervejarias