Identification of Bioactivity,Volatile and Fatty Acid Profile in Supercritical Fluid Extracts of Mexican arnica

Supercritical fluid extraction (SFE) is a sustainable technique used for the extraction of lipophilic metabolites such as pigments and fatty acids. Arnica plant is considered a potential candidate material with high antioxidant and antimicrobial activities. Therefore, in this study, a locally available Heterotheca inuloides, also known as Mexican arnica, was analyzed for the extraction of high-value compounds. Based on different pressure (P), temperature (T), and co-solvent (CoS), four treatments (T) were prepared. A maximum 7.13% yield was recovered from T2 (T = 60 °C, P = 10 MPa, CoS = 8 g/min), followed by 6.69% from T4 (T = 60 °C, P = 30 MPa, CoS = 4 g/min). Some bioactive sesquiterpenoids such as 7-hydroxycadalene, caryophyllene and δ-cadinene were identified in the extracts by GC/MS. The fatty acid profile revealed that the main components were palmitic acid (C16:0), followed by linoleic acid (C18:2ω6c), α-linolenic acid (C18:3ω3) and stearic acid (C18:0) differing in percent yield per treatment. Antibacterial activities were determined by the agar diffusion method, indicating that all the treatments exerted strong antibacterial activity against S. aureus, C. albicans, and E. coli strains. The antioxidant capacity of the extracts was also measured by three in vitro assays, DPPH, TEAC and FRAP, using Trolox as a standard. Results showed high antioxidant capacity enabling pharmaceutical applications of Mexican arnica.     

Molecular crowding and viscosity as determinants of translational diffusion of metabolites in subcellular organelles

The role of molecular crowding and viscosity on the apparent translational diffusion coefficient (ADC) of small metabolites was investigated in different subcellular organelles using the pulse-field gradient spin-echo 1H NMR technique. ADCs of metabolites with increasing radius of gyration (0.7 A < RG < 4.5 A) were measured in the cytoplasm of rat or chicken erythrocytes, in the nucleus of chicken erythrocytes, and in isolated rat liver mitochondria. Metabolite ADCs in these systems were compared with the corresponding ADCs determined in model solutions of increasing bulk viscosity but different molecular crowding. For solutions having the same viscosity, metabolite ADCs decreased with increasing concentration of cosolutes. This effect is adequately described by the modified Stokes-Einstein relationship, ADC = k/RG (1 + 2.5Phi), where k is a constant for a given temperature and Phi is an obstruction factor reporting the fractional volume of solution occupied by cosolutes, a measure of the molecular crowding in the solution. Cytoplasmic values of Phi for metabolites of different sizes did not depend exclusively on metabolite RG but on additional factors including the chemical nature of the metabolite, the presence of diffusional barriers, and metabolite-specific binding sites. In the case of water, nuclear Phi values approached those of the extracellular space while mitochondrial Phi values were significantly higher than those of the cytoplasm. Taken together, these results reveal important differences in molecular crowding within the different subcellular compartments, suggesting considerable diffusional heterogeneity for small metabolites within the different intracellular organelles.     

Limited validity of equations to predict the future h index

Regression equations to predict h index trajectories up to 10 years ahead have been recently derived from the analysis of data from a large calibration sample of neuroscientists. These equations were regarded by their proponents as potentially useful decision aids for funding agencies, peer reviewers, and hiring committees. This paper presents the results of a validation study in a sample of Spanish psychologists including neuroscience psychologists for whom the regression equations would be expected to apply but including also psychologists in other areas of the social/behavioral sciences for whom the applicability of the regression equations might be questionable. The results do not support the equations for any of the two groups: Errors of prediction were generally large and mostly positive, the more so the larger was the value of the h index used to make the prediction. Although the validity of these regression equations could still be investigated in additional cross-validation studies, an alternative approach to predicting future h indices is outlined and illustrated in this paper.     

Estimation of Coxiella burnetii prevalence in dairy cattle in intensive systems by serological and molecular analyses of bulk-tank milk samples

A large-scale investigation on Coxiella burnetii was carried out in dairy cattle herds from a Q fever-endemic region to evaluate the degree of exposure to C. burnetii and to estimate prevalences. This study included all of the dairy cattle herds from the province of Bizkaia, Northern Spain (n=178). Herds were visited between September 2009 and February 2010, and 100mL of bulk-tank milk (BTM) per farm was collected to be analyzed by ELISA and PCR. Blood samples were also taken from about 15 animals randomly selected from each herd. One hundred nineteen of the 178 studied herds (66.9±6.9%) were positive for the presence of anti-C. burnetii antibodies in BTM. Serum samples from 1,306 cows, 654 heifers, and 502 calves were analyzed by ELISA, and cows showed a statistically significantly higher seroprevalence (12.3±1.8%) than heifers (1.1±0.8%) and calves (0.0±0.0%). Eighty-nine herds (50.0±7.3%) had at least 1 seropositive animal, but within-herd prevalences higher than 20% were only observed in 24 herds (13.5±5.0%). A significant correlation was observed between BTM ELISA sample-to-positive control ratios and within-herd seroprevalence, being higher when considering only cows (R(2)=0.21). Animals from herds with negative BTM by ELISA showed a mean seroprevalence of 2.5%, whereas animals from herds with positive BTM samples had a statistically significantly higher seroprevalence (8.9%, F=19.7, degrees of freedom=1). The proportion of herds C. burnetii positive by BTM PCR was 51.7±7.3% (92/178). The widespread distribution of C. burnetii in cattle advocates for the implementation of Q fever control strategies.     

Natural Convection Drying at Low Temperatures of Previously Frozen Salted Meat

The drying of raw cured ham proceeds under natural convection. The aim of this work was to determine the effect of external resistance on the drying of frozen and salted Biceps femoris and Semimembranosus. Natural convection drying kinetics were obtained at 5, 10, 15, and 20°C. The D_e values obtained neglecting external resistance were underestimated. Activation energy, E_a, agreed with literature results. The use of a D_e value from literature and a calculated E_a allowed us to calculate D_e for the temperatures used in this study. The mass transfer coefficient (k) was estimated from a model taking external resistance and the calculated D_e into account. The k values agreed with the ones in literature; thus, under natural convection conditions, external mass transfer resistance must be considered.     

Surface characterization of P3OT thin films by variable temperature scanning force microscopy

In this work variable temperature scanning force microscopy techniques have been used to study poly(3-octylthiophene) (P3OT) thin film samples. Topography images in combination with scanning force spectroscopy have been applied to characterize the morphology and mechanical properties of the P3OT surface. It has been found that at room temperature lamellar islands appears on top of the polymer surface, while at temperatures higher than 35–45 °C these lamellas disappear and the polymer surface becomes homogeneous. This process is reversible and the lamellar structures are recovered when the sample is cooled down. In parallel, local force spectroscopy performed at each temperature shows a marked variation of the mechanical properties at about 30–40 °C, both in the polymer surface as well as in the lamellar islands. This points towards a conformational change in the P3OT molecules which loose planarity disrupting the close packing of the molecules on the lamellas.     

Optimization of the Drying Process of Carrot (Daucus carota v. Nantes) on the Basis of Quality Criteria

The drying curves and the degradation kinetics of three different quality attributes (total carotenoids (TC) and total polyphenols (TP) contents and antioxidant activity (AA)) of carrots during drying at different temperatures (from 40 to 90°C) have been experimentally evaluated and modeled. A diffusional model taking into account the solid shrinkage and both the external and internal water transfer resistances was used to accurately represent the water transfer in carrot during drying (average mean relative error (MRE) of 3.3 ± 0.6%). The effective moisture diffusivity was found to follow the Arrhenius relationship (E_a = 76.0 kJ/mol) and the mass transfer coefficient a linear dependence with air temperature. The Weibull model was used to satisfactorily simulate the degradation kinetics of the three quality attributes considered (average MRE of 2.8 ± 1.2% for TC content, 5.7 ± 1.0% for TP content, and 3.6 ± 1.8% for AA); these were the E_a of 52.7 kJ/mol for TC; 22.1 kJ/mol for TP; and 27.5 kJ/mol for AA kinetics. By using the proposed models, the estimated optimum drying temperature to best retain the total carotenoids content ranged between ca. 42–46°C; meanwhile, in order to maintain the TP content and the antioxidant activity at the highest levels, the drying needed to be carried out at temperatures of ca. 60–75°C. These results indicate that the TC retention is more influenced by the drying temperature, while the TP and AA retentions are more sensitive to drying time exposure. However, it was possible to establish a global optimum air temperature which ranged between 52.6 and 57.7°C, decreasing the TC, TP, and AA retentions by less than 2.2% from their respective optimal values.     

Influence of the Addition of Dietary Fiber on the Drying Curves and Microstructure of a Dry Fermented Sausage (Sobrassada)

The formulation of a dry fermented sausage has been modified by the addition of carrot dietary fiber (CDF; 3, 6, 9, and 12% [w/w]), and the influence of this change on the drying curves and food microstructure has been studied. The CDF content influenced the initial moisture content as well as the drying rate. A diffusion model taking into account the change in the product formulation has been proposed to simulate the drying curves. A constant mass transfer coefficient of 2.53 × 10^?8 m/s was obtained and the effective water diffusivity varied exponentially with the CDF content from 0.99 × 10^?11 m²/s (0% CDF) to 2.08 × 10^?11 m²/s (12% CDF). The simulation of the drying curves was satisfactory (mean relative error of 0.5 ± 0.1%). No differences in the microstructure related to the proteolytic process were found among samples with different CDF contents.     

Use of Novel Drying Technologies to Improve the Retention of Infused Olive Leaf Polyphenols

The infusion of phenolic extracts in dried fruits constitutes an interesting means of improving their nutritional content. However, drying can affect the further process of impregnation. In this work, different drying treatments (air temperature and ultrasound application) were applied to apple samples and impregnated with olive leaf extract. The application of ultrasound during drying did not significantly (p < 0.05) affect the infusion capacity of samples, but the ultrasonically assisted dried samples showed a greater antioxidant capacity than those conventionally dried. The highest content of oleuropein and verbascoside was found in samples dried at low temperature using ultrasound.