Short communication: Fourier-transform mid-infrared spectroscopy to predict coagulation and acidity traits of sheep bulk milk

Sheep milk is mainly transformed into cheese; thus, the dairy industry seeks more rapid and cost-effective methods of analysis to determine milk coagulation and acidity traits. This study aimed to assess the feasibility of Fourier-transform mid-infrared spectroscopy to determine milk coagulation and acidity traits of sheep bulk milk and to classify milk samples according to their renneting capacity. A total of 465 bulk milk samples collected in 140 single-breed flocks of Comisana (84 samples, 24 flocks) and Sarda (381 samples, 116 flocks) breeds located in Central Italy were analyzed for coagulation properties (rennet coagulation time, curd firming time, and curd firmness) and acidity traits (pH and titratable acidity) using standard laboratory procedures. Fourier-transform mid-infrared spectroscopy prediction models for these traits were built using partial least squares regression analysis and were externally validated by randomly dividing the full data set into a calibration set (75%) and a validation set (25%). The discriminant capacity of the rennet coagulation time prediction model was determined using partial least squares discriminant analysis. Prediction models were more accurate for acidity traits than for milk coagulation properties, and the ratio of prediction to deviation ranged from 1.01 (curd firmness) to 2.14 (pH). Moreover, the discriminant analysis led to an overall accuracy of 74 and 66% for the calibration and validation sets, respectively, with greater sensitivity for samples that coagulated between 10 and 20 min and greater specificity to detect early-coagulating (<10 min) and late-coagulating (20–30 min) samples. Results suggest that Fourier-transform mid-infrared spectroscopy has the potential to help the dairy sheep industry identify milk with better coagulation ability for cheese production and thus improve milk transformation efficiency. However, further research is needed before this information can be exploited at the industry level.     

Personality and smoking status: a meta-analysis.

We used meta-analytic techniques in an attempt to clarify the strength and direction of the association between smoking status and personality, which narrative reviews have indicated remains a largely inconsistent literature. Included were cross-sectional studies that reported personality data for healthy, adult smokers and nonsmokers using measures of personality traits derived from Eysenck's tripartite taxonomy of human personality. Of the 25 studies that contributed to the meta-analysis, 22 reported data on smoking status and extraversion and 22 reported data on smoking status and neuroticism. Meta-analysis using a fixed-effects framework indicated a significant difference between smokers and nonsmokers on both extraversion (p<.001) and neuroticism (p<.001) traits, which remained significant when a random-effects framework was used to accommodate significant between-study heterogeneity. These data from cross-sectional observational studies published between 1972 and 2001 indicate that both increased extraversion and increased neuroticism are associated with an increased likelihood of being a smoker rather than a nonsmoker, although in both cases the effect sizes indicated by the meta-analysis were small. We found no evidence that the strength of these associations varied with year of publication.     

Experimental Evaluation of Quality Parameters During Drying of Carrot Samples

The aim of this work was to evaluate the effect of operating conditions on the quality of dried foods, monitoring shrinkage, rehydration capacity, and color changes. Carrot samples of different shapes and dimensions were dried in a convective oven by air whose temperature and velocity were chosen in a range of physical significance. Two values of air velocity, i.e., 2.8 and 2.2 m/s, were considered; air temperature was chosen equal to 50 °C, 70 °C, and 85 °C. It was observed that more drastic drying conditions indeed improved the drying rate, but were also responsible for a decrease of food rehydration capacity. Food behavior was observed comparing some characteristic parameters as obtained upon fitting the experimental data by simple modeling equations. In particular, the drying curves were fitted by the Newton’s model, whereas, shrinkage was modeled by a linear relationship between volume variation and moisture content. Rehydration capacity was estimated by water regain percentage, which was evaluated after 5 h.     

PEO–PPO–PEO triblock copolymer/Nafion blend as membrane material for intermediate temperature DMFCs

This paper describes homogeneous triblock copolymer/Nafion blend membranes, which facilitate proton conduction in direct methanol fuel cells (DMFCs) at intermediate temperatures. The interaction between the two polymer components is investigated by FT-IR spectroscopy. The blend membranes show higher proton conductivity than recast Nafion under partially anhydrous conditions. Protons can be transported with the assistance of ether chain under such conditions at elevated temperature. In addition, the membranes exhibit more favourable methanol permeability and selectivity. This kind of blend membrane shows somewhat better performance in DMFC compared to bare recast Nafion at intermediate temperature (≥120 °C). This work is a first attempt in our group to design membrane materials with enhanced proton conductivity under conditions typical of intermediate temperature DMFCs.     

Experimental evidence of “latent gate oxide damages” in medium voltage power MOSFET as a result of heavy ions exposure

The results presented in this paper are related to an experimental study that has the aim to evidence the formation of “latent gate oxide damages” in medium voltage power MOSFETs during the impact with energetic particles. The understanding of these “latent defectiveness” can be an helpful aid in the comprehension of the mechanisms of breach of the oxide layer of MOS structures induced by single energetic particles impact (single event gate rupture). To properly detect the presence of “latent damages” we have developed a high resolution experimental set-up and identified an appropriate region in which the device have to be biased in order to trigger this kind of damage.     

Defect chemistry of nano-grained barium titanate films

Polycrystalline barium titanate thin films have been prepared with 100 ppm of B-site acceptor dopants Ca, Mg, and Mn via chemical solution deposition on base metal substrates. The films are fired in low pO₂ atmospheres at 900 °C to prevent substrate oxidation. All dopant species produce low loss, space-charge free material without secondary reoxidation anneals. We note that the dopant concentrations required to compensate for oxygen non-stoichiometry are substantially greater than expected by equilibrium thermodynamic calculations. This observation is rationalized in the context of a composite oxygen defect model with differing reduction enthalpies for grain interiors and surfaces.     

Diffusive Modeling of Aggradation and Degradation in Artificial Channels

The unsteady flow and solid transport simulation problem in artificial channels is solved using a three-equation model, coupled with a local erosion law. The three equations are the water mass and momentum balance equations, as well as the total solid load balance equation. It is shown that even during severe hydrological events inertial terms can be neglected in the momentum equation without any substantial change in the solution sought. Empirical equilibrium formulas were used to estimate the solid load as a function of the flow variables. Local erosion, due to the scour generated at the jump between two channels connected at different bottom elevations, was estimated adapting a literature formulation. The double order approximation time and space marching scheme, previously proposed for the solution of the unsteady flow problem in the fixed-bed case, is applied to the solution of the new system. The model was validated with both literature and new laboratory experimental data. No parameter calibration was used to fit the computed results to the experimental ones.     

Insights into the formation and degradation mechanisms of methylenedinitramine during the incubation of RDX with anaerobic sludge

In an earlier study, we reported that hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) biodegraded with domestic anaerobic sludge to produce a key RDX ring cleavage intermediate that was tentatively identified as methylenedinitramine (O2NNHCH2NHNO2) using LC/MS with negative electrospray ionization (ES-). Recently, we obtained a standard material of methylenedinitramine and thus were able to confirm its formation as the key initial RDX intermediate. In water alone or in the presence of sludge, methylenedinitramine decomposed to N20 and HCHO. Only in the presence of sludge HCHO converted further to carbon dioxide. To test our hypothesis that water was involved in the formation of methylenedinitramine during incubation of RDX with sludge, we allowed the energetic compound to biodegrade in several D2O/H2O solutions (90, 50, and 0% v/v). We observed three distinctive deprotonated or dedeuterated mass ions at 135, 136, and 137 Da that were attributed to the formation of nondeuterated (H-methylenedinitramine), monodeuterated (D1-methylenedinitramine), and dideuterated methylenedinitramine (D2-methylenedinitramine), respectively. Two controls were prepared in D2O both in the absence of sludge; the first contained methylenedinitramine, and the second contained RDX. Neither control produced any deuterated methylenedinitramine, thus excluding the occurrence of any abiotic D/H exchange between D2O and either methylenedinitramine or RDX. The results supported the occurrence of an initial enzymatic reaction on RDX, yet they did not provide compelling evidence on whether methylenedinitramine was an initial RDX enzymatic hydrolysis product or simply formed via the spontaneous hydrolysis of an anonymous initial RDX enzymatic product.