Test-day genetic analysis of condition score and heart girth in Holstein Friesian cows.

This study aimed to estimate heritability for condition score and heart girth using a test-day model, to investigate the genetic relationships between condition score, heart girth, and milk yield traits and to analyze the genetic relationships of condition score and heart girth measured at different stages of lactation. Cows from 25 dairy herds were scored for body condition and measured for heart girth at 3-mo intervals for 2 yr. Approximately 5000 test-day observations on condition score, heart girth, and milk fat and protein yield from 1344 Italian Friesian cows were analyzed using two approaches: 1) repeated observations for a trait were considered repeated measurements of the same trait; 2) observations for a trait collected in different stages of lactation (dry period, 1 to 75, 76 to 130, 131 to 210, and 211 to 300 DIM) were treated as different traits. (Co)variance components and related parameters were estimated using REML multiple-trait procedures and animal models with unequal design for different traits. Heritability estimates for fat and protein test-day yield and for test-day condition score and heart girth were 0.22, 0.18, 0.29, and 0.33, respectively. Condition score was negatively correlated with yield traits and positively correlated with heart girth, whereas genetic relationships between heart girth and milk yield traits were negligible. Heritability estimates were 0.27 for condition score recorded in the first half of lactation (1 to 75 and 76 to 130 DIM), 0.36 for condition score in the second half of lactation (131 to 210 and 211 to 300 DIM) and 0.32 for condition score recorded on dry cows. Genetic correlations between condition scores measured in different lactation stages were generally high (0.85 or more), with the exception of the relationships between the first and the last stage of lactation (0.74) and between the first half of lactation and the dry period (0.7). Heritability estimates for heart girth in different lactation stages ranged from 0.31 to 0.40, and genetic correlations between high girth measured in different lactation stages were higher than 0.80.     

A heat-flux based “building block” approach for solving heat conduction problems

A numerical approximation of the Green’s function equation based on a heat-flux formulation is given. It is derived by assuming as a functional form of the surface heat flux a stepwise variation with space and time. The obtained approximation is very important in investigation of the inverse heat conduction problems (IHCPs) because it gives a convenient expression for the temperature in terms of the heat flux components. Additionally, it is very important for the unsteady surface element (USE) method which is a modern boundary discretization method. Green’s function approximate solution equation (GFASE) also creates ‘naturally’ fixed groups or modules of work elements called “building blocks” that may be added together to obtain space and time values of temperature. In the current case, they are subject to a partial heating by an applied surface heat flux. The “building block” solution can be derived by using the various analytical and numerical approaches available in heat conduction literature though the exact analysis is preferable, as discussed in the text. Poorly-convergent series deriving from Green’s functions approach are replaced by closed-form algebraic solutions.     

Image analysis to quantify histological and immunofluorescent staining of ex vivo skin and skin cell cultures

Image processing steps and analysis techniques were developed for the quantification of photomicrographs obtained from light and fluorescence microscopy. The substrates examined were either skin cell cultures, such as normal human keratinocytes (NHK) or fibroblasts, or ex vivo skin sections. Examples of the analyses are provided for the comparison of skincare active ingredient treated samples vs. placebo to demonstrate the utility of the methods to quantify and provide numerical data for a procedure that is typically qualitative in nature and based on observations by a histologist. Quantifiable experiments that are discussed include: Fontana Masson staining for melanin expression; Nile red staining to detect cellular lipid droplets; nuclei staining with diamidino‐phenylindole (DAPI); and immunofluorescent staining of protein expression with a primary antibody directed against the protein (antigen) and a secondary antibody tagged with a fluorescent dye (Alexa Fluor 488) against the primary antibody.     

Temperature effects on the enhanced or deteriorated buoyancy-driven heat transfer in differentially heated enclosures filled with nanofluids

ABSTRACT

A two-phase model based on the double-diffusive approach is used to perform a numerical study of natural convection in differentially heated vertical cavities filled with water-based nanofluids, assuming that Brownian diffusion and thermophoresis are the only slip mechanisms by which the solid phase can develop a significant relative velocity with respect to the liquid phase. The system of the governing equations of continuity, momentum, and energy for the nanofluid, and continuity for the nanoparticles, is solved through a computational code, which incorporates three empirical correlations for the evaluation of the effective thermal conductivity, the effective dynamic viscosity, and the thermophoretic diffusion coefficient, all based on the literature experimental data. The pressure–velocity coupling is handled using the SIMPLE-C algorithm. Numerical simulations are executed for three different nanofluids, using the diameter and the average volume fraction of the suspended nanoparticles, as well as the cavity width, the average temperature of the nanofluid, and the temperature difference imposed across the cavity, as independent variables. It is found that the heat transfer performance of the nanofluid relative to that of the base fluid increases notably with increasing the average temperature, showing a peak at an optimal particle loading. Conversely, the other controlling parameters have moderate effects.     

Phenotypic and genotypic characterization of Oenococcus oeni strains isolated from Italian wines

A phenotypic and genotypic characterization of 84 Oenococcus oeni isolates from Italian wines of different oenological areas was carried out. Numerical analysis of fatty acid profiles grouped the isolates into two clusters at low level of similarity (63%), the minor cluster containing seven isolates besides the type and the reference strains. Forthy-eight O. oeni isolates, representative of the two clusters, showed no differences in their metabolic properties (heterolactic fermentation pattern, citrate degradation capability and formation of some secondary metabolites). Moreover, the analysis of species-specific randomly amplified polymorphic DNA and 16S-23S rDNA intergenic spacer region polymorphism as well as the sequence-specific separation of V3 region from 16S rDNA by denaturing gradient gel electrophoresis demonstrated a substantial homogeneity among the isolates. On the basis of ApaI Pulsed Field Gel Electrophoresis (PFGE) restriction patterns, the 84 isolates were grouped into five different clusters at 70% similarity, but no correlation with the phenotypic groups could be demonstrated. However, by combining phenotypic and genotypic data, the 84 O. oeni isolates grouped into eight phenotypic-genotypic combined profiles and a relationship between the origin of the isolates and their combined profile became evident, so that a sort of strain specificity can be envisaged for each wine-producing area.     

Combustion of fine aluminum and magnesium powders in water

Micron-sized metal powders carried by a nitrogen flow were fed along the axis of a cylindrical hydrogen/oxygen diffusion flame. The particles ignited and burned in the water vapor at approximately 2500 K. Experiments were performed at atmospheric pressure. The environment in which particles burned was characterized in detail using computational fluid dynamics. The computations confirmed that the metal powders burned in water while the effect of oxygen and other oxidizing species could be neglected. Combustion was characterized experimentally for micron-sized powders of both aluminum and magnesium. Particle size distributions were measured using low-angle laser light scattering. Optical emission of the burning particles was recorded using filtered photomultiplier tubes. Measured durations of individual particle emission pulses were assumed to represent their burn times; these data were classified into logarithmically spaced time bins. The distribution of the particle burn times was correlated with their size distributions assuming that larger size particles burned longer. It was observed that correlation between the burn times, t, and particle diameters, D, can be approximately described as t ∼ D^0.64 and t ∼ D^0.68 for aluminum and magnesium powders, respectively. The results were compared to previous reports and possible reasons for discrepancies between the present and earlier results were discussed.     

Experimental study of dry reforming of biogas in a tubular anode-supported solid oxide fuel cell

The performance of a tubular Ni/YSZ anode supported SOFC directly fed by an anaerobic digestion simulated biogas, with an extra addition of carbon dioxide to operate in conservative operating conditions to avoid coking on the anode support, was investigated. The fuel cell has been tested at a fixed oven temperature of 800 °C and under biogas/CO₂ mixtures with different volumetric ratios, fuel utilization (FU) and current densities. Polarization curves and performance maps were obtained to better understand the influence of the investigated operational parameters on the cell behavior. Furthermore, since the tubular geometry enables an easy separation of the anode and cathode exhaust gases, the anode off-gas has been collected and monitored through a gas-chromatograph under open circuit voltage to investigate on the catalytic behavior of a Ni-based state-of-the-art anode. For corresponding operative conditions, performances of the cell for biogas/CO₂ 1/1.5 (i.e. CH₄/CO₂ 30/70) and 1/2 (i.e. CH₄/CO₂ 24/76) were at least 2% and 4% lower than the case 1/1 (i.e. CH₄/CO₂ 20/80), respectively. The highest efficiency of 43.4% was reached at 17.5 A and FU = 70%.     

Optimization of the working cycle for a hydrogen production and power generation plant based on aluminum combustion with water

The working cycle of a novel hydrogen and power generation system based on aluminum combustion with water is analyzed in order to evaluate the best performance in terms of energy conversion efficiency. The system exploits the exothermic reaction between aluminum and steam and produces thermal power for a super-heated steam cycle and hydrogen as a by-product of the reaction.