Direct measurement of DNA-mediated adhesion between lipid bilayers

Multivalent interactions between deformable mesoscopic units are ubiquitous in biology, where membrane macromolecules mediate the interactions between neighbouring living cells and between cells and solid substrates. Lately, analogous artificial materials have been synthesised by functionalising the outer surface of compliant Brownian units, for example emulsion droplets and lipid vesicles, with selective linkers, in particular short DNA sequences. This development extended the range of applicability of DNA as a selective glue, originally applied to solid nano and colloidal particles. On very deformable lipid vesicles, the coupling between statistical effects of multivalent interactions and mechanical deformation of the membranes gives rise to complex emergent behaviours, as we recently contributed to demonstrate [Parolini et al., Nature Communications, 2015, 6, 5948]. Several aspects of the complex phenomenology observed in these systems still lack a quantitative experimental characterisation and fundamental understanding. Here we focus on the DNA-mediated multivalent interactions of a single liposome adhering to a flat supported bilayer. This simplified geometry enables the estimate of the membrane tension induced by the DNA-mediated adhesive forces acting on the liposome. Our experimental investigation is completed by morphological measurements and the characterisation of the DNA-melting transition, probed by in-situ F\"{o}rster Resonant Energy Transfer spectroscopy. Experimental results are compared with the predictions of an analytical theory that couples the deformation of the vesicle to a full description of the statistical mechanics of mobile linkers. With at most one fitting parameter, our theory is capable of semi-quantitatively matching experimental data, confirming the quality of the underlying assumptions.Comment: 16 pages, 7 figure

Organic and healthy: assessing the impact of claims and third-party certifications on premium price

Organic food consumption is steadily growing across a variety of product categories. While consumers are increasingly focused on the healthiness of the food they purchase, companies are experimenting alternative ways to communicate and guarantee the organic and health-related benefits of their products. This study explores the effect of different combinations of front-of-package (FoP) components on premium price. Specifically, we focus on the interaction and visual salience of FoP organic claims, health-related claims, and third-party organic certifications. Based on an analysis of grocery sales data and product packaging visuals, the study identifies FoP component combinations that could maximise premiums. We offer insights to marketing managers and companies involved in enhancing the communication of organic food benefits to consumers

Dagli osservatóri agli Osservatòri

Quelli che hanno avuto il Vesuvio negli occhi, le loro storie di scienziati e di uomini, sono il tema di questo breve racconto. Storie di osservatóri, quindi, che hanno studiato il vulcano con passione, affascinati e sedotti da una montagna umbratile e solenne. Ma anche storie di Osservatòri, di contesti e tempi, ovvero, anch’essi mutevoli, in cui la scienza si organizza e si disorganizza per comprendere, prevedere, provvedere

Photon creation in a spherical oscillating cavity

We study the photon creation inside a perfectly conducting, spherical oscillating cavity. The electromagnetic field inside the cavity is described by means of two scalar fields which satisfy Dirichlet and (generalized) Neumann boundary conditions. As a preliminary step, we analyze the dynamical Casimir effect for both scalar fields. We then consider the full electromagnetic case. The conservation of angular momentum of the electromagnetic field is also discussed, showing that photons inside the cavity are created in singlet states.Comment: 14 pages, no figure

Espécies de aves não nativas no Brasil

Many non-native species of birds have been introduced beyond the limits of their natural geographic ranges, where they may subsequently establish viable populations and perhaps become invasive. Much attention in the literature has been devoted to the study of bird introductions, but relatively little of that attention has been focused on introductions to the continental tropics. Here, we compile published data on records of non-native bird species introduced to the wild in Brazil, with the aim of organizing and standardizing available information to facilitate future studies in this context. A total of 59 bird species were classified as introduced in Brazil, with one further species believed to be a recent natural colonist. Published information implies that 14 species have established or probably established non-native populations in Brazil, while a further 10 species have possibly established non-native populations. In this context, we map the non-native distributions of non-native species of birds in Brazil. Additional research is needed to confirm the status of these species, as well as to establish practical measures to combat and control introductions.Key words: alien birds, biological invasions, exotic species.Muitas espécies não nativas de aves têm sido introduzidas para além dos seus limites geográficos naturais, onde elas posteriormente podem estabelecer populações viáveis e tornarem-se invasoras. Muita atenção tem sido dedicada a estudos com introdução de aves na literatura, mas relativamente pouca atenção tem sido focada em introduções nos continentes tropicais. No presente trabalho, compilamos os dados publicados sobre os registros de espécies de aves não nativas introduzidas à vida selvagem no Brasil, com o objetivo de organizar e padronizar as informações disponíveis para facilitar futuros estudos nesse contexto. Um total de 59 espécies de aves foi considerado introduzido no Brasil. Há, ainda, uma espécie adicional que acreditamos ser um recente colonizador natural. As informações publicadas indicam que 14 espécies têm estabelecido ou provavelmente estabeleceram populações não nativas no Brasil, enquanto outras 10 espécies têm a possibilidade de estabelecerem populações não nativas. Nesse contexto, mapeamos a distribuição das espécies não nativas de aves no Brasil. Pesquisas adicionais são necessárias para confirmar a situação dessas espécies, bem como para estabelecer medidas práticas para combater e controlar as introduções. Palavras-chave: aves invasoras, invasões biológicas, espécies exóticas

Electronic cigarette: a threat or an opportunity for public health? State of the art and future perspectives

The e-cigarette, also known as e-cig, represents an emerging issue of great concern for public health. The aim of the present report was to explore the scientific literature about the use of electronic cigarette (e-cig), with a particular reference to the features of “toxicological safety”, “effectiveness in overcoming the addiction to smoking the traditional cigarette” and “necessary research agenda”. The efficacy of e-cig for smoking cessation is uncertain: some authors found that it can be a valid support, but long-term cessation rate has not be assessed. Other studies evidenced that e-cig is often used not for quitting smoking but to avoid smoking ban for traditional cigarettes and, even, some researches evidenced that it appears to contribute to nicotine addiction. E-cig smoking seems to be less dangerous of conventional cigarettes, but its use is not risk-free. Besides, cases of accidental or intentional poisoning with liquid solutions of e-cig have been reported. Also, the smoke of e-cig decreases indoor air quality, releasing particulate matter and other toxics that can persist on surfaces for days and generating passive exposure. These phenomena are similar to environmental tobacco smoke produced by conventional smoking, that is the sum of second- and third-hand smoke. We propose to call them “environmental electronic smoke”, “electronic-second- hand smoke” and “electronicthird-hand smoke”, respectively. Uncertainties relating to e-cig features determined the sequence, in the short term, of warnings and regulations approved and then replaced. In conclusion, although in recent years many researches were performed, evidences is limited and there is a need to study in deep all these issues

Sepiolinae (Mollusca, Cephalopoda) from the Ligurian Sea

A collection of 130 specimens of Sepiola (ligulata, robusta, rondeletii, intermedia), 115 Rondeletiola minor, 90 Sepietta ( obscura, neglecta) and more abundant samples of S. oweniana obtained by trawl fishing in the Ligurian Sea are briefly illustrated in terms of depth distribution, sex ratio and maturity stages

Synthesis and anti-picornavirus activity of homo-isoflavonoids

Substituted homo-isoflavonoids were synthesized in order to study their in vitro anti-picornavirus activity. The maximum non-toxic concentration of the compounds for susceptible cells (HeLa) was determined, and the ability of non-cytotoxic concentrations to interfere with plaque formation by human rhinovirus (HRV) 1B and 14 and poliovirus (PV) 2 was examined. All the tested compounds were weakly effective against PV-2, while they exhibited a variable degree of activity against HRV-1B and -14 infection. Serotype 1B was much more sensitive than 14 to the action of the compounds, and the presence of one or more chlorine atoms increased the antiviral effect in all homo-isoflavonoids tested, confirming the positive influence of this substituent on activity

Epidemiology of intensive care unit-acquired sepsis in Italy: results of the SPIN-UTI network

BACKGROUND: Sepsis is the major cause of mortality from any infectious disease worldwide. Sepsis may be the result of a healthcare associated infection (HAI): the most frequent adverse events during care delivery especially in Intensive Care Units (ICUs). The main aim of the present study was to describe the epidemiology of ICU-acquired sepsis and related outcomes among patients enrolled in the framework of the Italian Nosocomial Infections Surveillance in ICUs - SPIN-UTI project. STUDY DESIGN: Prospective multicenter study. METHODS: The SPIN-UTI network adopted the European protocols for patient-based HAI surveillance. RESULTS: During the five editions of the SPIN-UTI project, from 2008 to 2017, 47.0% of HAIs has led to sepsis in 832 patients. Overall, 57.0% episodes were classified as sepsis, 20.5% as severe sepsis and 22.5% as septic shock. The most common isolated microorganisms from sepsis episodes were Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa. The case fatality rate increased with the severity of sepsis and the mean length of ICU-stay was significantly higher in patients with ICU-acquired sepsis than in patients without. CONCLUSION: Our study provides evidence that ICU-acquired sepsis occurs frequently in Italian ICU patients and is associated with a high case fatality rate and increased length of stay. However, in order to explain these findings further analyses are needed in this population of ICU patient