Equilibrium and out-of-equilibrium dynamics in a molecular layer of azopolymer floating on water studied by Interfacial Shear Rheology

We report the details of the construction and calibration of an ultra sensitive surface rheometer, inspired by the setup described in [C.F. Brooks et al Langmuir 15, 2450 (1999)], which makes use of high resolution video tracking of the motion of a floating magnetized needle and is capable of measuring the viscoelastic response of a Langmuir monolayer with an accuracy of 10^-5 N/m. This instrument is then employed for the rheological characterization of a Langmuir monolayer of a photosensitive azobenzene polymer, which can be brought out of equilibrium by a suitable photoperturbation. The complex dynamic shear modulus G= G' + i G" is measured as a function of temperature and illumination power and wavelength. The reversible rheological ch anges induced in the film by photo-perturbation are monitored during time, observing a transition from a predominantly elastic (G' > G'') to a viscoelastic (G' \approx G'') regime. These results are confirmed by comparison with independent measurements performed by us using other rheological techniques. Finally a discussion is made, taking into account the results of a recent x-ray photon correlation spectroscopy experiment on the same polymer in equilibrium and out of equilibrium.Comment: Proceedings of the International Discussion Meeting on Relaxation in Complex Systems, Rome, 2009 12 pages, 7 figure

Metagenomics of pigmented and cholesterol gallstones: the putative role of bacteria

There is growing evidence for bacteria playing a role in the pathogenesis and formation of pigmented gallstones from humans. These studies mainly involved cultivation of gallstone-associated bacteria and 16S rRNA profiling, providing an indirect link between processes involved in gallstone formation by the bacteria in-situ. Here, we provide functional metagenomic evidence of a range of genes involved in bile stress response, biofilm formation, and anaerobic energy metabolism by Gram-negative Klebsiella in pigmented gallstones from a 76-year-old male patient. Klebsiella was also present in one cholesterol-type stone in a 30-year-old female patient who had additional cholesterol gallstones characterised by Gram-positive bacteria. Pigmented stones further revealed a predominance of genes involved in carbohydrate metabolism, whilst cholesterol stones indicated a profile dominanted by protein metabolism possibly reflecting known chemical differences between Gram-negative and Gram-positive biofilm matrices. Archaeal genes were not detected. Complementary carbon and hydrogen isotopic analyses of cholesterol within the patients' stones revealed homogeneity, suggesting a common diet or cholesterol biosynthesis pathway that has little influence on microbial composition. This pilot study provides a framework to study microbial processes that play a potential role in gallstone formation across markedly different types of stones and patient backgrounds

A new 3D concentration gradient maker and its application in building hydrogels with a 3D stiffness gradient

For a deeper knowledge of phenomena at cell and tissue level, for understanding the role on bimolecular signalling and for the development of new drugs it is important to recreate in vitro environments that mimic the physiological one. Spatial gradients of soluble species guide the cells' morphogenesis, and they range in a three-dimensional (3D) environment. Gradients of mechanical properties, which have a 3D pattern, could lead cell migration and differentiation. In this work, a new 3D Concentration Gradient Maker able to generate 3D concentration gradients of soluble species was developed, which could be used for differential perfusion of scaffolds. The same device can be applied to build hydrogel matrixes with a 3D gradient of mechanical properties. Computational dynamic fluid analysis was used to develop the gradient generator; the validation of the 3D gradient of stiffness was carried out using finite elements analysis and experimental studies. The device and its application could bring improvements in studying phenomena related to cell chemotaxis and mechanotaxis, but also to differentiation in the simultaneous presence of gradients in both soluble chemical species and substrate stiffnes

The association between vitamin D and BDNF on cognition in older adults in Southern Brazil

OBJECTIVE: To estimate the association between vitamin D and the cognitive decline of older adults and evaluate whether this association is mediated by brain-derived neurotrophic factor (BDNF) serum concentration. METHODS: Cross-sectional study nested in a population-based cohort. Of the 604 participants in the complementary examination of the EpiFloripa Study, 576 older adults (60 years or older) were eligible for the study. The outcome is cognitive decline evaluated by the Mini-Mental State Examination, the exposure is vitamin D, and BDNF is the mediator. The control variables are age, sex, per capita family income, and educational level. The direct effect of vitamin D and BDNF on cognitive decline and the indirect effect mediated by BDNF was evaluated using path analysis, with the estimation of standardized coefficients. RESULTS: Among the participants, we observed a direct and positive effect of vitamin D on cognitive function (Coef: 0.06; 95%CI 0.02 to 0.11; p < 0.001) and serum BDNF concentration (Coef: 21.55; 95%CI 9.92 to 33.17; p = 0.002), i.e., the higher the vitamin D, the higher the cognitive function and serum level of BDNF. CONCLUSION: There was an association between vitamin D on serum BDNF and on cognitive decline in older adults. Moreover, BDNF did not have an effect on cognitive decline, so BDNF was not a mediator of the vitamin D effect on cognitive decline

Data-driven Predictive Latency for 5G: A Theoretical and Experimental Analysis Using Network Measurements

The advent of novel 5G services and applications with binding latency requirements and guaranteed Quality of Service (QoS) hastened the need to incorporate autonomous and proactive decision-making in network management procedures. The objective of our study is to provide a thorough analysis of predictive latency within 5G networks by utilizing real-world network data that is accessible to mobile network operators (MNOs). In particular, (i) we present an analytical formulation of the user-plane latency as a Hypoexponential distribution, which is validated by means of a comparative analysis with empirical measurements, and (ii) we conduct experimental results of probabilistic regression, anomaly detection, and predictive forecasting leveraging on emerging domains in Machine Learning (ML), such as Bayesian Learning (BL) and Machine Learning on Graphs (GML). We test our predictive framework using data gathered from scenarios of vehicular mobility, dense-urban traffic, and social gathering events. Our results provide valuable insights into the efficacy of predictive algorithms in practical applications

Nursing students’ experience of risk assessment, prevention and management: a systematic review

Introduction:  As a fundamental dimension of quality, the patient safety and healthcare workers safety in the healthcare environment depend on the ability of each healthcare workers (whether administrators or technicians) to reduce the probability of error. This review focused on nursing students. The aim was to assess level and determinants of knowledge about risk assessment, risk prevention and risk management of nursing students. Methods: A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Two reviewers searched the bibliographic databases Pubmed, Scopus and Cinahl to collect all the available articles in English and Italian issued between 2015 and August 2019. To obtain an exhaustive string search, the following keywords were combined through Boolean operators AND and OR: Clinical Risk Assessment, Nursing Education, Nursing Student*, Patient Safety. The authors assessed the quality of the evidence by using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) method.  Results: Twelve papers are included. Although the literature on the nursing student's error is limited, their frequencies are worrying. Some authors have created a model of prevention of clinical error based on three level. However, the majority of nursing students don’t felt confident with a patient safety. Many authors shown that patient safety education was delivery by lecture, laboratory or simulation sessions. Conclusions: This review underlines the need to revise the nursing curriculum on patient safety and the need to think what educational methodology is the better for the student to create a safe care. &nbsp

Aumento na sobrevida de crianças de grupos de peso baixo ao nascer em Santa Catarina

OBJECTIVE: To analyze factors associated with survival in the first year of life. METHODS: A historical cohort study was carried out using data from live birth and mortality information systems, including 90,153 live birth records and 1,053 records of death before age one year in hospitals in the cities of Florianópolis and São José, Southern Brazil, between 1999 and 2006. Survival curves were estimated (Kaplan-Meier) for birthweight categories, date of birth (four-year periods), and type of maternity. Proportional hazard ratios for mortality were calculated using Cox regression. RESULTS: Survival (98.8%) did not change among all birthweight categories, but increased among babies born weighing under 2,000 g (77.7% to 81.2%, p=0.029), between 1999-2002 and 2003-2006. There was an increase in the proportion of babies under 2,000 g in the second period. Type of hospital was significantly associated with probability of survival. CONCLUSIONS: Probability of survival is higher among babies born in private hospitals and in the teaching hospital in all birthweight categories combined and for babies born weighing under 2,000 g. Survival among the latter increased in the most recent period. However, the infant mortality rate did not change between the two periods given the increase in the prevalence of children with ligther birth weight.OBJETIVO: Analizar factores asociados con la sobrevida en el primer año de vida. MÉTODOS: Estudio de cohorte histórica realizado con datos de los sistemas de información de nacimiento y mortalidad sobre 90.153 registros de nacidos vivos y 1.053 registros de óbitos de menores de un año en hospitales de Florianópolis y Sao José, Sur de Brasil, entre 1999 y 2006. Fueron estimadas curvas de sobrevida (Kaplan-Meier) para grupos de peso al nacer, período (cuatrienios) y tipo de maternidad. Se calcularon tasas de riesgos proporcionales para óbitos utilizando regresión de Cox. RESULTADOS: La sobrevida (98,8%) no se modificó entre los grupos de peso, pero aumentó en los grupos de menos de 2.000g (77,7% para 81,2%, p=0,029) entre los cuatrienios de 1999 a 2002 y 2003 a 2006. Hubo aumento de menores de 2.000g en el segundo cuatrienio estudiado. El tipo de hospital fue asociado significativamente con la probabilidad de sobrevida. CONCLUSIONES: Hay mayor probabilidad de sobrevida entre nacidos en hospitales privados y en el hospital de enseñanza para todos los grupos de peso y para el grupo de menos de 2000 g. La sobrevida de los grupos de peso por debajo de 2000g aumentó en el cuadrienio más reciente. Mientras, el coeficiente de mortalidad infantil no disminuyó en ese período, ya que la prevalencia de los nacidos en grupos de menor peso también aumentó.OBJETIVO: Analisar fatores associados à sobrevida no primeiro ano de vida. MÉTODOS: Estudo de coorte histórica foi realizado com dados dos sistemas de informação de nascimento e mortalidade sobre 90.153 registros de nascidos vivos e 1.053 registros de óbitos de menores de um ano em hospitais de Florianópolis e São José, SC, entre 1999 e 2006. Foram estimadas curvas de sobrevida (Kaplan-Meier) para grupos de peso ao nascer, período (quadriênios) e tipo de maternidade. Foram calculadas razões de riscos proporcionais para óbitos utilizando regressão de Cox. RESULTADOS: A sobrevida (98,8%) não se modificou entre os grupos de peso, mas aumentou nos grupos de menos de 2.000 g (77,7% para 81,2%, p = 0,029) entre os quadriênios de 1999 a 2002 e 2003 a 2006. Houve aumento de menores de 2.000 g no segundo quadriênio estudado. O tipo de hospital foi associado significativamente à probabilidade de sobrevida. CONCLUSÕES: Há maior probabilidade de sobrevida entre nascidos em hospitais privados e no hospital de ensino para todos os grupos de peso e para o grupo de menos de 2000 g. A sobrevida dos grupos de peso abaixo de 2000 g aumentou no quadriênio mais recente. Entretanto, o coeficiente de mortalidade infantil não diminuiu nesse período, pois a prevalência dos nascidos em grupos de menor peso também aumentou

Salvado de harina y salvado de fécula de mandioca como potenciales excipientes para comprimidos

Objectives: The physicochemical characteristics of bran of cassava starch flour and bran of cassava flour (viz. organoleptic characteristics, pH value, moisture content, total ashes, lipid, protein, starch and fiber contents) and biopharmacotechnical parameters (viz. granulometry, flow capacity, angle at rest, outflow time and apparent density) were evaluated aiming at assessing their potential use as tablet excipients. Methodos: Three tablet formulations of venlafaxine hydrochloride were proposed, having as excipients bran of cassava flour, bran of cassava starch flour and Starch 1500®. The tablets were produced using two different pressures (98±5 MPa and 32±6 Mpa) and their mechanical (hardness and friability) and dissolubility characteristics were evaluated. Results and Conclusions: The tablets produced with both cassava flours, using higher pressures, presented similar physicochemical characteristics to those obtained with the excipient Starch1500®, thus indicating that cassava flours possess the potential to be used as disintegrating agents in tablets.Objetivos: Se evaluaron características físico-químicas del salvado de harina y del salvado de la fécula de mandioca (características organolépticas, pH, humedad, cenizas totales y contenido de lípidos, proteínas, almidones y fibras) y biofarmacotécnicas (granulometría, capacidad de flujo, ángulo en reposo, tiempo de salida y densidad aparente) con el objetivo de evaluar el uso de estos residuos como excipientes para comprimidos. Métodos: Se propusieron tres formulaciones en comprimidos de venlafaxina teniendo como excipientes salvado de harina de mandioca, salvado de fécula de mandioca y Starch 1500 ®. Las pastillas se produjeron utilizando dos presiones diferentes (98 ± 5 MPa y 32 ± 6 Mpa). Las características mecánicas (dureza y friabilidad) y de disolución de los comprimidos se evaluaron. Resultados y Conclusiones: Los comprimidos producidos con ambos salvados de mandioca, utilizando las presiones más elevadas, presentaron características físico-químicas similares a las obtenidas con el excipiente Starch1500®, indicando que las harinas de mandioca poseen potencial para ser utilizadas como agentes desintegrantes en comprimidos

Interpretation of Thermal Response Tests in Borehole Heat Exchangers Affected by Advection

ABSTRACT We focus on the treatment of thermal response test data when both advection and short-period changes of surface temperature occur. We used a moving line source model to simulate temperature-time signals under an advective thermal regime. The subsurface thermal conductivity, the Darcy velocity and the borehole thermal resistance were inferred by means of an optimisation procedure. In case of Darcy velocity lower than 10 -7 m s -1 , the underground thermal conductivity is comparable to that obtained by means of the infinite line source model, which assumes a purely conductive thermal regime. The optimisation analysis was finally applied to real thermal response test data. The temperature-time curves were filtered to remove the disturbing spectral components associated with a non-optimal thermostatic behaviour of the apparatus. This produced reliable estimates of thermal and hydraulic parameters. An independent method based on the analysis of temperature-depth logs was also used to validate the inferred groundwater flow. INTRODUCTION The thermal power that can be extracted with borehole heat exchangers (BHE) depends mainly on the thermal properties of the underground, and in particular, on thermal conductivity. Laboratory measurements of thermo-physical properties can be unfeasible, as core samples are often unavailable in boreholes. Thus, in-situ tests are routinely used to determine subsurface and borehole thermal properties. Tests record the underground temperature variation with time due to a constant heat that is injected (or extracted) by means of a carrier fluid into a borehole acting as a heat exchanger. The most commonly used model to analyse temperature-time curves obtained from these tests is the infinite line source (ILS). If some conditions are fulfilled, this model can give rapid and appropriate estimations of thermal parameters. On the other hand, several flaws can often affect the data interpretation. Some of them are related to the model assumptions, which imply a purely conductive heat transfer regime, a homogeneous medium, no vertical heat-flow and infinite length of the borehole. Others have to do with the difficulty in the proper thermal insulation of the test equipment, and consequently with the oscillations of the carrier fluid temperature due to surface air temperature changes, which generally produce a periodic offset in the recorded temperature-time curves. In this paper, we discuss the treatment of the thermal response test (TRT) data when both advection caused by groundwater flow and periodic changes of air surface temperature occur. An approach based on the moving line source (MLS) model is tested with simulations of temperaturetime signals obtained under different hypothesis of thermal and hydraulic conditions. Then, the same procedure is applied to real TRT data to estimate thermal conductivity, borehole thermal resistance and Darcy velocity. The magnitude of the inferred groundwater flow is finally checked by means of an independent method based on the analysis of the undisturbed temperaturedepth records