54 research outputs found
Poly(vinyl alcohol) molecular bottlebrushes nucleate ice
Ice binding proteins (IBP) have evolved to limit the growth of ice but also to promote ice formation by ice-nucleating proteins (INPs). IBPs, which modulate these seemingly distinct processes, often have high sequence similarities, and molecular size/assembly is hypothesized to be a crucial determinant. There are only a few synthetic materials that reproduce INP function, and rational design of ice nucleators has not been achieved due to outstanding questions about the mechanisms of ice binding. Poly(vinyl alcohol) (PVA) is a water-soluble synthetic polymer well known to effectively block ice recrystallization, by binding to ice. Here, we report the synthesis of a polymeric ice nucleator, which mimics the dense assembly of IBPs, using confined ice-binding polymers in a high-molar-mass molecular bottlebrush. Poly(vinyl alcohol)-based molecular bottlebrushes with different side-chain densities were synthesized via a combination of ring-opening metathesis polymerization (ROMP) and reversible additionāfragmentation chain-transfer (RAFT) polymerization, using āgrafting-toā and āgrafting-throughā approaches. The facile preparation of the PVA bottlebrushes was performed via selective hydrolysis of the acetate of the poly(vinyl acetate) (PVAc) side chains of the PVAc bottlebrush precursors. Ice-binding polymer side-chain density was shown to be crucial for nucleation activity, with less dense brushes resulting in colder nucleation than denser brushes. This bio-inspired approach provides a synthetic framework for probing heterogeneous ice nucleation and a route toward defined synthetic nucleators for biotechnological applications
Pertinence of salt-related knowledge and reported behaviour on salt intake in adults : a cross-sectional study
The association between salt-related knowledge, attitude, behaviour (KAB) and actual salt consumption in Greek adults is uncertain. This study investigates the correlation between salt intake, gauged by 24-h urinary sodium excretion, with salt-related KAB. It further explores how socio-demographic factors influence these behaviors. Salt consumption was evaluated using a 24-h urinary sodium test, and compared to self-reported KAB data. Knowledge and behavior scores related to salt were computed. An overall cohort-adjusted model examined the relationship between daily salt consumption, knowledge and behavior scores, and certain covariates. Through the stratification by the cohort random effect, two models were established (Cohort I Adults; Cohort II Students) examining the same relationships of the overall cohort model. 463 Greek adults participated. The average salt intake was 9.54 g/day, nearly double the WHO recommendation. Significant differences in knowledge scores were noted based on sex, age, education, and BMI. A trend suggesting lower discretionary salt use with increased salt intake was observed (p = 0.06). However, comprehensive analysis revealed no direct correlation between salt intake and either knowledge (p = 0.562) or behavior scores (p = 0.210). The results emphasize the need for food product reforms by industry stakeholders and accelerated efforts towards reducing salt intake
The combination of colistin and doripenem is synergistic against Klebsiella pneumoniae at multiple inocula and suppresses colistin resistance in an in vitro pharmacokinetic/pharmacodynamic model
There has been a resurgence of interest in aerosolization of antibiotics for treatment of patients with severe pneumonia caused by multidrug-resistant pathogens. A combination formulation of amikacin-fosfomycin is currently undergoing clinical testing although the exposure-response relationships of these drugs have not been fully characterized. The aim of this study was to describe the individual and combined antibacterial effects of simulated epithelial lining fluid exposures of aerosolized amikacin and fosfomycin against resistant clinical isolates of Pseudomonas aeruginosa (MICs of 16 mg/liter and 64 mg/liter) and Klebsiella pneumoniae (MICs of 2 mg/liter and 64 mg/liter) using a dynamic hollow-fiber infection model over 7 days. Targeted peak concentrations of 300 mg/liter amikacin and/or 1,200 mg/liter fosfomycin as a 12-hourly dosing regimens were used. Quantitative cultures were performed to describe changes in concentrations of the total and resistant bacterial populations. The targeted starting inoculum was 10(8) CFU/ml for both strains. We observed that neither amikacin nor fosfomycin monotherapy was bactericidal against P. aeruginosa while both were associated with rapid amplification of resistant P. aeruginosa strains (about 10(8) to 10(9) CFU/ml within 24 to 48 h). For K. pneumoniae, amikacin but not fosfomycin was bactericidal. When both drugs were combined, a rapid killing was observed for P. aeruginosa and K. pneumoniae (6-log kill within 24 h). Furthermore, the combination of amikacin and fosfomycin effectively suppressed growth of resistant strains of P. aeruginosa and K. pneumoniae In conclusion, the combination of amikacin and fosfomycin was effective at maximizing bacterial killing and suppressing emergence of resistance against these clinical isolates
Designing a consequentially based study into the online support of pre-service teachers in the UK
This paper reports on the design of a pilot doctoral study into the online support of pre-service teachers. It highlights the significance of a consequential, rather than deontological, perspective in guiding the development of a study's design. The study initially aimed to explore pre-service teachersā perceptions and use of social media on their school placements by setting up groups on Facebook and Twitter. However, several problems occurred in relation to the recruitment of participants. It became increasingly clear that there was significance in the positionality of the researcher as an āoutsiderā to the research context and the potential role for gatekeepers in understanding remote research sites. An ethical framework was used to make a more comprehensive analysis of the issues at play, which helped identify ways of proceeding. A redesign of the study followed with a stronger rationale for the way consequential considerations can help address deontological concerns
Estudo experimental do processo de rotomoldagem de PELBD: efeitos sobre a morfologia e estabilidade dimensional
ICTs based Physics Learning
In this paper we concentrate on the implementation and the results of teaching and learning methods which are based on use of Information and Communication Technologies (ICTs) for understanding of Physics concepts. These methods are simulations, virtual reality, video games and were used to students of all levels, from elementary school to university for undergraduates and postgraduates students. Also these methods include a wide representative range of Physics` branches
Factors Affecting GreekĀ Nursesā Caring Behaviors: The Role of Nursesā Spirituality and the Spiritual Climate ofĀ Hospitals
The aim of the present study was to examine the effect of nursesā personality, spirituality, and spiritual care in nursesā caring behaviors. A descriptive, cross-sectional study was conductedĀ in two hospitals, located in Athens, Greece. Data were collected by a four-part self-reported questionnaire. The results showed that work experience seems to play anĀ important and positiveĀ role on nursesā caring behaviors, and all personality traits, except neuroticism. Also, spirituality and spiritual climate are significant factors predicting nurses'Ā caring behaviors. Moreover, aĀ hospitalsā spiritual climate can positively influence all domains of nursing care (p < 0.001). Nurses spirituality (faith) and hospital spiritual climate can also positively influence nursing care. Ā© 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature
Emotional intelligence and professional boredom among nursing personnel in greece
Occupational (professional) boredom results in low performance at work. It has been positively associated with high levels of anxiety and depression as well as premature death. However, occupational boredom has not been extensively studied among working nurses. This study aimed to investigate the relationship between emotional intelligence and occupational boredom in nurses working in both public (52.9%) and private (47.1%) health units in Greece. A cross-sectional study was conducted among a convenience sample of 189 nurses (84.7% females) with an average age of 40 years. Emotional intelligence was evaluated with the use of The Trait Emotional Intelligence Questionnaire-Short Form and Professional boredom was assessed with the use of the Boredom Proneness Scale. The majority of Nurses showed relatively high values of total Emotional Intelligence (EI), and marginally low values of overall Professional Boredom. A statistically significant negative correlation was found between the overall Professional Boredom of Nurses and the Well-being, Self-control, Emotionality and Sociability subscales of EI, as well as total EI (p < 0.001). Multiple linear regression analyses showed that the three dimensions of EI (Well-being, Self-Control and Emotionality) explained 39.0% of the variability of the total Professional Boredom of the working Nurses. Ā© 2021 by the authors. Licensee MDPI, Basel, Switzerland
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