Supercritical carbon dioxide: putting the fizz into biomaterials

This paper describes recent progress made in the use of high pressure or supercritical fluids to process polymers into three-dimensional tissue engineering scaffolds. Three current examples are highlighted: foaming of acrylates for use in cartilage tissue engineering; plasticization and encapsulation of bioactive species into biodegradable polyesters for bone tissue engineering; and a novel laser sintering process used to fabricate three-dimensional biodegradable polyester structures from particles prepared via a supercritical route

The use of electronic nose as alternative non-destructive technique to discriminate flavored and unflavored olive oils

Cv. Arbequina extra virgin olive oils (EVOO) were flavored with cinnamon, garlic, and rosemary and characterized. Although flavoring significantly affected the physicochemical quality parameters, all oils fulfilled the legal thresholds for EVOO classification. Flavoring increased (20 to 40%) the total phenolic contents, whereas oxidative stability was dependent on the flavoring agent (a slight increase for rosemary and a decrease for cinnamon and garlic). Flavoring also had a significant impact on the sensory profiles. Unflavored oils, cinnamon, and garlic flavored oils had a fruity-ripe sensation while rosemary flavored oils were fruity-green oils. Fruit-related sensations, perceived in unflavored oils, disappeared with flavoring. Flavoring decreased the sweetness, enhanced the bitterness, and did not influence the pungency of the oils. According to the EU regulations, flavored oils cannot be commercialized as EVOO. Thus, to guarantee the legal labelling requirement and to meet the expectations of the market-specific consumers for differentiated olive oils, a lab-made electronic nose was applied. The device successfully discriminated unflavored from flavored oils and identified the type of flavoring agent (90 ± 10% of correct classifications for the repeated K-fold cross-validation method). Thus, the electronic nose could be used as a practical non-destructive preliminary classification tool for recognizing olive oils’ flavoring practice.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support by national funds FCT/MCTES to CIMO (UIDB/00690/2020) and to CEB (UIDB/04469/2020) units and to the Associate Laboratory SusTEC (LA/P/0007/2020), as well as to BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte 2020—Programa Operacional Regional do Norte. Nuno Rodrigues thanks to National funding by FCT—Foundation for Science and Technology, P.I., through the institutional scientific employment program-contractinfo:eu-repo/semantics/publishedVersio

Climatology of easterly wave disturbances over the tropical South Atlantic

A 21-yr climatology of Easterly Waves Disturbances (EWDs) over the Tropical South Atlantic (TSA) has been examined using data from the European Centers for Medium-Range Weather Forecasting (ECMWF) interim reanalysis (ERAI) and satellite data. This includes the frequency distribution of EWDs and their interannual variability. The large-scale environment associated with EWDs has been investigated for the coastal region of Northeast Brazil (NEB) for the rainy (April-August) season using a composite analysis. To better understand the life cycle of EWDs, an automated tracking scheme has been used to track vorticity centers associated with the EWDs in the ERAI data. EWDs were first identified in ERAI, resulting in 518 observed cases. These were found to show notable interannual variability with around 16-40 episodes by year and with average lifetime of 4-6 days. Of the identified EWDs, 97% reached the coast of NEB, of which 64% were convective in nature and 14% moved across the NEB region and reached the Amazon. The annual occurrence of EWDs seems to be lower (higher) during El Niño (La Niña). The monthly occurrence of EWDs shows higher activity in the rainy season. EWDs originate in association with five types of system: cold fronts, convective clusters from the west coast of Africa, Intertropical Convergence Zone and Tropical Upper Tropospheric Cyclonic Vortices. The composite analysis presents strong relative vorticity (RV) and divergence anomalies at low levels, as well as in the vertical profiles of relative humidity and vertical velocity (omega). The precipitation composites show that the EWDs propagate between the TSA and NEB and contribute at least 60% of the total rainfall over the east coast of NEB throughout the rainy season

Prospects for ACT: simulations, power spectrum, and non-Gaussian analysis

A new generation of instruments will reveal the microwave sky at high resolution. We focus on one of these, the Atacama Cosmology Telescope, which probes scales 1000<l<10000, where both primary and secondary anisotropies are important. Including lensing, thermal and kinetic Sunyaev-Zeldovich (SZ) effects, and extragalactic point sources, we simulate the telescope's observations of the CMB in three channels, then extract the power spectra of these components in a multifrequency analysis. We present results for various cases, differing in assumed knowledge of the contaminating point sources. We find that both radio and infrared point sources are important, but can be effectively eliminated from the power spectrum given three (or more) channels and a good understanding of their frequency dependence. However, improper treatment of the scatter in the point source frequency dependence relation may introduce a large systematic bias. Even if all thermal SZ and point source effects are eliminated, the kinetic SZ effect remains and corrupts measurements of the primordial slope and amplitude on small scales. We discuss the non-Gaussianity of the one-point probability distribution function as a way to constrain the kinetic SZ effect, and we develop a method for distinguishing this effect from the CMB in a window where they overlap. This method provides an independent constraint on the variance of the CMB in that window and is complementary to the power spectrum analysis.Comment: 22 pages, 11 figures. Submitted to New Astronomy. High resolution figures provided at http://www.princeton.edu/~khuffenb/pubs/prospects-act.htm

FTIR-chemometric analytical methodology as a tool for clustering oils from centenarian olive trees grown in the Côa Valley region

The centenarian olive trees are part of the historical and cultural heritage of the Côa Valley region where a significant number of these specimens can be found. They have high importance in olive grove heritage; however, their genetic and phenotypic diversity is still poorly studied. Recently, Fourier Transform Infrared (FTIR) spectroscopy start to be widely used in several studies in the food field, becoming a powerful analytical tool for the analysis of edible oils and fats. This technique has numerous advantages, allowing a fast and non-destructive analysis, and requiring minimal sample preparation. In this context, FTIR has been applied to classify and identify different fats, detection of virgin olive oils adulteration, determination of trans fatty acids and evaluation of oil mixtures' composition in foods, all this based on the spectral profiles. Considering that there is a great diversity of centenarian olive trees in which the varieties are unknown, the objective of this work was to use the FTIR technique to identify groups of olive oils with similar chemical characteristics, thus reducing the time and required amount of samples for analysis.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support by national funds FCT/MCTES to CIMO (UIDB/00690/2020) and to Associate Laboratory for Green Chemistry-LAQV (UIDB/50006/2020). Nuno Rodrigues and Aran Santamaria-Echar thanks to National funding by FCT- Foundation for Science and Technology, P.I., through the institutional scientific employment program-contract. This work was financially supported by the project “COA/BRB/0035/2019” OLIVECOA - Centenarian olive trees of Côa Valley region: rediscovering the past to valorise the future funded by the Foundation for Science and Technology (FCT, Portugal).info:eu-repo/semantics/publishedVersio

How well does the HadGEM2-ES coupled model represent the Southern Hemisphere storm tracks?

This study presents an assessment of the ability of the Hadley Centre Global Environment Model version 2—Earth system configuration (HadGEM2-ES)—in simulating the mid-latitude storm tracks over the Southern Hemisphere (SH). The storm tracks are primarily assessed using cyclone tracking using data from a 4 member ensemble of 27-year simulations of HadGEM2-ES over the historical period, and the European Centre for Medium-Range Weather Forecasts Interim Reanalysis. Both winter and summer periods are considered and contrasted. Results show that the storm track (ST) climatology of HadGEM2-ES presents similar patterns to those of the reanalysis. However, the model tends to represent the austral winter ST position with an equatorward bias and a zonal bias in the spiral towards the pole. The main differences were found during the austral winter, with large track density biases over the Indian Ocean indicating a poor representation of the ST in this specific region. This was found to be related to two factors. First, the large negative genesis biases over South America, Antarctic Peninsula and the Antarctic coast. Second, the model resolution and the representation of the Andes Mountains in South America. The link between STs and the large-scale circulation is examined and shows at upper levels an equatorward jet position bias of the subtropical jet and a negative bias in the eddy-driven, associated with a large cold bias over the extratropical and polar regions. The analysis of the large-scale circulation shows that the split jet during winter has problems in the model linked to these biases, including geopotential anomaly and sea surface temperature biases. Consequently, in general the track densities over the Southern oceans are underestimated in the austral winter. During summer, the results show the STs move poleward and there is a single eddy-driven jet, which is represented relatively well compared with the winter situation. These factors tend to reduce the differences seen in the cyclone track distribution biases. Although the model has biases in the ST behaviour in the SH it is still considered that these do not preclude this model being used for perturbation and future projection studies

Effect of the thickness on the photocatalytic and the photocurrent properties of ZnO films deposited by spray pyrolysis

In this work, we have investigated the structure, morphology, photoluminescence, photocatalytic and photocurrent properties of ZnO thin films as a function of their film thickness (tZnO) fabricated via ultrasonic spray pyrolysis technique. The X-Ray diffraction patterns exhibited the formation of polycrystalline wurtzite phase of ZnO. Scanning electron microscopy images showed the uniform morphology with nanorod structure. The photosensitivity and photocatalytic efficiency are found to be optimum at tZnO = 1200 nm and are attributed to the improved photogeneration of charge carriers and higher concentration of oxygen vacancies. A direct correlation is established between the photosensitivity and photodegradation process. The incident photon-to-electron conversion efficiency (IPCE) and photocatalytic efficiency for the ZnO film at tZnO = 1200 nm are estimated to be 31.5% and 100% respectively. The obtained result suggests that ZnO thin films are potential candidates for applications in various optoelectronic devices.This study has been partially supported by Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UIDB/FIS/04650/2020 (JPBS) and DST SERB Project ECR/2017/002537(K.K.). Author KVA acknowledges DST, Govt. of India for the Inspire fellowship (IF170601)

How a turn to critical race theory can contribute to our understanding of 'race', racism and anti-racism in sport

As long as racism has been associated with sport there have been consistent, if not coordinated or coherent, struggles to confront its various forms. Critical race theory (CRT) is a framework established to challenge these racialized inequalities and racism in society and has some utility for anti-racism in sport. CRT's focus on social justice and transformation are two areas of convergence between critical race theorists and anti-racists. Of the many nuanced and pernicious forms of racism, one of the most obvious and commonly reported forms of racism in sport, racial abuse, has been described as a kind of dehumanizing process by Gardiner (2003), as those who are its target are simultaneously (re)constructed and objectified according to everyday myth and fantasy. However, this is one of the many forms of everyday racist experiences. Various forms of racism can be experienced in boardrooms, on television, in print, in the stands, on the sidelines and on the pitch. Many times racism is trivialized and put down as part of the game (Long et al., 2000), yet its impact is rarely the source of further exploration. This article will explore the conceptualization of 'race' and racism for a more effective anti-racism. Critical race theory will also be used to explore the ideas that underpin considerations of the severity of racist behaviour and the implications for anti-racism. © The Author(s) 2010

Composition-dependent xBa(Zr0.2Ti0.8)O3-(1-x)(Ba0.7Ca0.3)TiO3 bulk ceramics for high energy storage applications

This work reports the composition dependent microstructure, dielectric, ferroelectric and energy storage properties, and the phase transitions sequence of lead free xBa(Zr0.2Ti0.8)O3-(1-x)(Ba0.7Ca0.3)TiO3 [xBZT-(1-x)BCT] ceramics, with x = 0.4, 0.5 and 0.6, prepared by solid state reaction method. The XRD and Raman scattering results confirm the coexistence of rhombohedral and tetragonal phases at room temperature (RT). The temperature dependence of Raman scattering spectra, dielectric permittivity and polarization points a first phase transition from ferroelectric rhombohedral phase to ferroelectric tetragonal phase at a temperature (TR-T) of 40 0C and a second phase transition from ferroelectric tetragonal phase - paraelectric pseudocubic phase at a temperature (TT-C) of 110 0C. The dielectric analysis suggests that the phase transition at TT-C is of diffusive type and the BZT-BCT ceramics are a relaxor type ferroelectric materials. The composition induced variation in the temperature dependence of dielectric losses was correlated with full width half maxima (FWHM) of A1, E(LO) Raman mode. The saturation polarization (Ps) ≈ 8.3 μC/cm2 and coercive fields ≈ 2.9 kV/cm were found to be optimum at composition x = 0.6 and is attributed to grain size effect. It is also shown that BZT-BCT ceramics exhibit a fatigue free response up to 105 cycles. The effect of a.c. electric field amplitude and temperature on energy storage density and storage efficiency is also discussed. The presence of high TT-C (110 0C), a high dielectric constant (εr ≈ 12285) with low dielectric loss (0.03), good polarization (Ps) ≈ 8.3 μC/cm2) and large recoverable energy density (W = 121 mJ/cm3) with an energy storage efficiency (η) of 70 % at an electric field of 25 kV/cm in 0.6BZT 0.4BCT ceramics make them suitable candidates for energy storage capacitor applications.This work was supported by (i) DST-SERB, Govt. of India through grant ECR/2017/000068 and (ii) UGC through Grant Nos. F.4-5(59-FRP/ 2014(BSR)). The authors AR Jayakrishnan acknowledges Central University of Tamil Nadu, India for his Ph.D fellowship. K.V.A. acknowledges the DST for the Inspire fellowship IF170601. J.P.B.S. is grateful for the financial support through the FCT Grant SFRH/BPD/92896/2013.The authors thank to Vivek Sudarsanan from the Central University of Kerala for XRD measurements.info:eu-repo/semantics/publishedVersio