Effect of filtration on virgin olive oil stability during storage

The effect of filtration and dehydration on the stability and quality of virgin olive oil during storage at room temperature (25 °C) and under accelerated conditions (40 °C) was studied. Different types of monovarietal olive oil, namely unfiltered (UF), filtered (F) and filtered‐dehydrated (FD), were obtained from Arbequina, Colombaia, Cornicabra, Picual and Taggiasca cultivars. Results showed that filtration and dehydration decreased the rate of hydrolysis of the triacylglycerol matrix, especially at the higher temperature and in oils with a higher initial free acidity (e.g. free acidity of 0.82% and 0.63% in UF and FD Colombaia samples, respectively, after 8 months of storage), and delayed the appearance of rancid defects (e.g. UF and FD Arbequina samples lost extra‐virgin grade after 10 and 12 months of storage, respectively). The formation of simple phenols due to the hydrolysis rate of their secoiridoid derivatives was also greater in unfiltered olive oils (e.g. 174 μmol/kg and 137 μmol/kg in UF and FD Picual samples, respectively, after 8 months of storage). Thus, filtration and especially dehydration could help to prolong the shelf life of high‐quality and less stable olive oils like those obtained from the Arbequina and Colombaia varieties.     

Impact of Parameter Variations on Circuits and Microarchitecture

Parameter variations, which are increasing along with advances in process technologies, affect both timing and power. Variability must be considered at both the circuit and microarchitectural design levels to keep pace with performance scaling and to keep power consumption within reasonable limits. This article presents an overview of the main sources of variability and surveys variation-tolerant circuit and microarchitectural approaches     

Reverse Micellar Extraction of Lysozyme Using Two Dialkyl Sodium Phosphinates

The extraction of lysozyme was studied using di‐(2,4,4‐trimethylpentyl) sodium phosphinate, R₂POONa, and di‐(2,4,4‐trimethylpentyl) sodium dithiophosphinate, R₂PSSNa. For a R₂POONa reverse micellar system, all lysozyme was removed from the aqueous phase when the pH of the aqueous solution was set below the pI of the protein. The extraction of lysozyme into a R₂PSSNa reverse micellar system was independent of the pH of the aqueous phase. A solubilization limit of lysozyme exists in the R₂POONa reverse micellar phase. The lysozyme recovery was 70% from the R₂POONa reverse micellar phase, and less than 10% from the R₂PSSNa reverse micellar phase.     

Generalization of the possibility of eliminating the filtration step in the determination of acid-soluble chloride content in cement and concrete by potentiometric titration

In this work, it is demonstrated that it is possible to eliminate the filtration step in the determination of the acid-soluble chloride content of cement and concrete by potentiometric titration, irrespective of the method used for detecting the end-point of the titration. Extensive analytical results are presented corresponding to several types of cement and to a broad range of chloride concentrations in concrete. Some requirements to avoid errors in such analytical determinations are discussed.     

Evaluation of heat and oxidative damage during storage of processed tomato products. I. Study of heat damage indices

The evolution of heat damage during storage of tomato pulp, puree and paste was studied by accelerated aging tests. Heat damage indices—5‐hydroxymethyl‐2‐furfural (HMF), furosine and colour changes (ΔE)—were evaluated for tomato products stored at 30, 40 and 50 °C for up to 90 days. Furosine and ΔE values increased following pseudo‐zero‐order kinetics, and the higher the solid content of the products, the higher were the rate constant values. HMF formation followed pseudo‐first‐order kinetics in tomato pulp and pseudo‐zero‐order kinetics in puree and paste samples. Data show that heat damage reactions in tomato products proceed even at room temperature, and the kinetic model provided can be used to predict changes occurring during shelf‐life. © 2002 Society of Chemical Industry     

Coating with artificial matrices from collagen and sulfated hyaluronan influences the osseointegration of dental implants

Dental implants are an established therapy for oral rehabilitation. High success rates are achieved in healthy bone, however, these rates decrease in compromised host bone. Coating of dental implants with components of the extracellular matrix is a promising approach to enhance osseointegration in compromised peri-implant bone. Dental titanium implants were coated with an artificial extracellular matrix (aECM) consisting of collagen type I and either one of two regioselectively low sulfated hyaluronan (sHA) derivatives (coll/sHA1Δ6s and coll/sHA1) and compared to commercial pure titanium implants (control). After extraction of the premolar teeth, 36 implants were inserted into the maxilla of 6 miniature pigs (6 implants per maxilla). The healing periods were 4 and 8 weeks, respectively. After animal sacrifice, the samples were evaluated histomorphologically and histomorphometrically. All surface states led to a sufficient implant osseointegration after 4 and 8 weeks. Inflammatory or foreign body reactions could not be observed. After 4 weeks of healing, implants coated with coll/sHA1Δ6s showed the highest bone implant contact (BIC; coll/sHA1Δ6s: 45.4 %; coll/sHA1: 42.2 %; control: 42.3 %). After 8 weeks, a decrease of BIC could be observed for coll/sHA1Δ6s and controls (coll/sHA1Δ6s: 37.3 %; control: 31.7 %). For implants coated with coll/sHA1, the bone implant contact increased (coll/sHA1: 50.8 %). Statistically significant differences could not be observed. Within the limits of the current study, aECM coatings containing low sHA increase peri-implant bone formation around dental implants in maxillary bone compared to controls in the early healing period.     

Effect on the journal impact factor of the number and document type of citing records: a wide-scale study

We studied the effect on journal impact factors (JIF) of citations from documents labeled as articles and reviews (usually peer reviewed) versus citations coming from other documents. In addition, we studied the effect on JIF of the number of citing records. This number is usually different from the number of citations. We selected a set of 700 journals indexed in the SCI section of JCR that receive a low number of citations. The reason for this choice is that in these instances some citations may have a greater impact on the JIF than in more highly-cited journals. After excluding some journals for different reasons, our sample consisted of 674 journals. We obtained data on citations that contributed to the JIF for the years 1998?C2006. In general, we found that most journals obtained citations that contribute to the impact factor from documents labeled as articles and reviews. In addition, in most of journals the ratio between citations that contributed to the impact factor and citing records was greater than 80% in all years. Thus, in general, we did not find evidence that citations that contributed to the impact factor were dependent on non-peer reviewed documents or only a few citing records.     

A single-phase model for liquid-feed DMFCs with non-Tafel kinetics

An isothermal single-phase 3D/1D model for liquid-feed direct methanol fuel cells (DMFC) is presented. Three-dimensional (3D) mass, momentum and species transport in the anode channels and gas diffusion layer is modeled using a commercial, finite-volume based, computational fluid dynamics (CFD) software complemented with user supplied subroutines. The 3D model is locally coupled to a one-dimensional (1D) model accounting for the electrochemical reactions in both the anode and the cathode, which provides a physically sound boundary condition for the velocity and methanol concentration fields at the anode gas diffusion layer/catalyst interface. The 1D model – comprising the membrane–electrode assembly, cathode gas diffusion layer, and cathode channel – assumes non-Tafel kinetics to describe the complex kinetics of the multi-step methanol oxidation reaction at the anode, and accounts for the mixed potential associated with methanol crossover, induced both by diffusion and electro-osmotic drag. Polarization curves computed for various methanol feed concentrations, temperatures, and methanol feed velocities show good agreement with recent experimental results. The spatial distribution of methanol in the anode channels, together with the distributions of current density, methanol crossover and fuel utilization at the anode catalyst layer, are also presented for different opperating conditions.