HPLC quantification of biogenic amines in cheeses: correlation with PCR-detection of tyramine-producing microorganisms

The consumption of food and beverages containing high amounts of biogenic amines (BA) can have toxicological effects. BA found in foods and beverages are synthesized by the microbial decarboxylation of certain amino acids. This paper reports the concentrations of BAs in a number of commercial cheeses, as determined by HPLC. The cheeses studied were made from raw and pasteurized milk of different origin, and were subjected to different ripening periods. BA concentrations were lower in short ripening period than in long ripening period cheeses, and higher in cheeses made from raw milk than in those made from pasteurized milk. The highest BA concentrations were recorded in blue cheeses made from raw milk. Tyramine was the most commonly recorded and abundant BA. The presence of tyramine-producing bacteria was determined by PCR, and a good correlation obtained between the results of this method and tyramine detection by HPLC. These methods could be used to complement one another in the detection and quantification of tyramine in cheese prevention of tyramine accumulation in cheese.     

Thermal Effects on the Gas Transmission Properties of Ionomers Used in Food Packaging Applications

Polyethylene-based ionomers, due to the presence of ionic aggregates, display a time-dependent crystalline morphology if submitted to thermal treatments. As a consequence gas permeability, which is strongly affected by physical morphology, is also found to be time dependent in previously thermally treated ionomer samples. The effect of sample exposure at 65°C and of successive ageing at 35°C on gas transmission properties of three different ethylene– acrylic acid ionomers (characterized by a different amount of acrylic acid groups, percentage of neutralization and type of counterions) has been investigated. In particular the changes in oxygen and carbon dioxide permeabilities due to thermal treatments at 65°C and subsequent ageing at 35°C have been monitored. X-Ray diffraction analysis and differential scanning calorimetry have been used to elucidate these changes in transport properties.     

Short-run statistical process control: Q-Chart enhancements and alternative methods

The first two tables in Reference 1 are incorrect. Corrected tables are provided below. The errors do not affect the conclusions or the discussion in that paper.     

Aquaporins Are One of the Critical Factors in the Disruption of the Skin Barrier in Inflammatory Skin Diseases

The skin is the largest organ of the human body, serving as an effective mechanical barrier between the internal milieu and the external environment. The skin is widely considered the first-line defence of the body, with an essential function in rejecting pathogens and preventing mechanical, chemical, and physical damages. Keratinocytes are the predominant cells of the outer skin layer, the epidermis, which acts as a mechanical and water-permeability barrier. The epidermis is a permanently renewed tissue where undifferentiated keratinocytes located at the basal layer proliferate and migrate to the overlying layers. During this migration process, keratinocytes undertake a differentiation program known as keratinization process. Dysregulation of this differentiation process can result in a series of skin disorders. In this context, aquaporins (AQPs), a family of membrane channel proteins allowing the movement of water and small neutral solutes, are emerging as important players in skin physiology and skin diseases. Here, we review the role of AQPs in skin keratinization, hydration, keratinocytes proliferation, water retention, barrier repair, wound healing, and immune response activation. We also discuss the dysregulated involvement of AQPs in some common inflammatory dermatological diseases characterised by skin barrier disruption.     

Pathogenetic Mechanisms of Hypertension–Brain-Induced Complications: Focus on Molecular Mediators

There is growing evidence that hypertension is the most important vascular risk factor for the development and progression of cardiovascular and cerebrovascular diseases. The brain is an early target of hypertension-induced organ damage and may manifest as stroke, subclinical cerebrovascular abnormalities and cognitive decline. The pathophysiological mechanisms of these harmful effects remain to be completely clarified. Hypertension is well known to alter the structure and function of cerebral blood vessels not only through its haemodynamics effects but also for its relationships with endothelial dysfunction, oxidative stress and inflammation. In the last several years, new possible mechanisms have been suggested to recognize the molecular basis of these pathological events. Accordingly, this review summarizes the factors involved in hypertension-induced brain complications, such as haemodynamic factors, endothelial dysfunction and oxidative stress, inflammation and intervention of innate immune system, with particular regard to the role of Toll-like receptors that have to be considered dominant components of the innate immune system. The complete definition of their prognostic role in the development and progression of hypertensive brain damage will be of great help in the identification of new markers of vascular damage and the implementation of innovative targeted therapeutic strategies.     

A glucose-specific metric to assess predictors and identify models

In diabetes, the mean square error (MSE) metric is extensively used for assessing glucose prediction methods and identifying glucose models. One limitation of this metric is that, by equally treating errors in hypo-, eu-, and hyperglycemia, it is not able to weight the different clinical impact of errors in these three situations. In this paper, we propose a new cost function, which overcomes this limitation and can be used in place of MSE for several scopes, in particular for assessing the quality of glucose predictors and identifying glucose models. The new metric called glucose-specific MSE (gMSE) modifies MSE with a Clark error grid inspired penalty function, which penalizes overestimation in hypoglycemia and underestimation in hyperglycemia, i.e., the most harmful conditions on a clinical perspective. From a mathematical point of view, gMSE retains sensitivity of MSE and inherits some of its important mathematical features, in particular it has no local minima, simplifying the optimization. This makes it suitable for model identification purposes also. First, the goodness of it is demonstrated by means of three experiments, designed ad hoc to evidence its sensitivity to accuracy, precision, and distortion in glucose predictions. Second, a prediction assessment problem is presented, in which two real prediction profiles are compared. Results show that the MSE chooses the worst clinical situation, while gMSE correctly selects the situation with less clinical risk. Finally, we also demonstrate that models identified minimizing gMSE are more accurate in potentially harmful situations (hypo- and hyperglycemia) than those obtained by MSE.     

Controlled filling and external cleaning of multi-wall carbon nanotubes using a wet chemical method

A controlled, material-independent and adaptable cold wet chemical procedure is described. It allows organic and inorganic compounds to be confined inside multi-wall carbon nanotubes. The procedure mainly consists of a lyophilization process to fill multi-wall carbon nanotubes (MWCNTs), and a washing method to clean their outer surface without removing the encapsulated material. The technique was tested by synthesizing CdS crystals inside the nanotubes. Morphological and structural studies of the CdS crystals demonstrated a complete control of the synthesis process, and the possibility of maximizing the crystal size and the filling efficiency that approached 70% of open-ended nanotubes.     

New method for monitoring of adsorption column saturation and regeneration I. Demonstration of the measurement principle

A new method suitable for the on-line monitoring of adsorption column saturation/regeneration cycles was developed based on the discovery that the electrical resistance of adsorbents changes dramatically upon adsorption and returns to its original value upon desorption, and that this change can be measured reliably. The phenomenon was demonstrated on four different adsorbent/adsorbate systems, on both single particles and in a packed bed between parallel plates. The observed phenomenon was studied on the carbon/CO2 system in more detail, because of the availability of extensive literature data. It was found that the resistance change in this system correlated with the amount of CO2 adsorbed. The correlation was used to construct an adsorption isotherm based on resistance change data.