The sanitizing action of essential oil-based solutions against Salmonella enterica serotype Enteritidis S64 biofilm formation on AISI 304 stainless steel

Bacterial adhesion and biofilm formation by Salmonella enterica serovar Enteritidis is a serious concern in the food processing industry; organism persistence in biofilms represents a continual source of contamination. Due to unsuccessful disinfection processes and emerging resistance, conventional control methods are rapidly becoming ineffective, necessitating the development of new control strategies. The following study evaluated the anti-biofilm effect of disinfectant solutions formulated with essential oils (EOs) of peppermint (Mentha piperita) and lemongrass (Cymbopogon citratus) against biofilm formation by S. enterica serotype Enteritidis S64 on stainless steel surface AISI 304 (#4) after 10, 20 and 40 min of contact. A minimum inhibitory concentration (MIC) of 7.8 μL/mL was found for both EOs and disinfectant solutions were formulated based on these MIC values. Ten minutes of sanitizing solution contact significantly reduced (p ≤ 0.05) adhered bacterial populations for both EOs tested. After 20 and 40 min of treatment, cell counts were not detected. Thus, M. piperita and C. citratus EOs can be considered convenient, quality alternatives to the application of conventional sanitizing agents in the food industry; further, use of these EOs addresses the increasing consumer demand for natural products.     

Determination of naturally occurring progestogens in bovine milk as their oxime derivatives using high performance liquid chromatography–electrospray ionization–tandem mass spectrometry

BACKGROUND: Hormones and hormone‐like substances which are present in the environment have been repeatedly accused of being the cause of most endocrine disruption. However, the possible role of endogenous hormones in food of animal origin deserves to be discussed as well. The relation between steroid hormones and several human health problems has been previously reported, such as prostate and breast cancer, perturbation of human reproduction and endocrine disruption on humans and wildlife. This research is particularly concerned with cow's milk, which contains a considerable amount of sex hormones. RESULTS: A liquid chromatography–tandem mass spectrometry method has been developed for the simultaneous detection and quantification of four naturally occurring steroid hormones in commercial bovine milk (pregnenolone (P₅), progesterone (P₄), 17‐hydroxypregnenolone (17‐OHP₅), 17‐hydroxyprogesterone (P₄)). Oxime derivatives of steroids were analyzed in positive ionization and multiple reaction monitoring mode. Methodology has been validated according to Decision 2002/657/EC criteria. CONCLUSION: This method has been successfully used in real samples. It is fast and easy‐handling and provides a useful tool for the assessment of progestogens in bovine milk. Copyright © 2010 Society of Chemical Industry     

Adaptive control design for a boost inverter

In this paper, a novel control strategy for a nonlinear boost inverter is proposed. The idea is based on generating an autonomous oscillator that does not need an external reference signal. This aim is achieved by using energy-shaping methodology with a suitable Hamiltonian function which defines the desired system behavior. A phase controller is added to the control law in order to achieve 180°-synchronization between both parts of the circuit as well as synchronize the voltage output with a pre-specified signal, e.g. synchronization with the electrical grid. An adaptive control is designed for dealing with the common problem of unknown load. In order to analyze the stability of the full system, singular perturbation approach is used. The resulting control is tested by means of simulations.     

Impact of Starch Gelatinization on the Kinetics of Maillard Reaction in Freeze-Dried Potato Systems

The objective of the present work was to contribute to the understanding of the changes in water-distribution and water–solids interactions that take place after starch gelatinization and to elucidate their influence on the kinetics of Maillard reaction in low-moisture potato starch systems. Maillard reaction was studied in freeze-dried native (NS) and gelatinized (GS) potato starch systems at 70°C. Water sorption isotherms were studied in a wide range of relative humidities (RH) and Guggenheim-Anderson-de Boer (GAB) model was applied. Thermal transitions were studied by differential scanning calorimetry; molecular mobility was estimated through time-resolved ¹H NMR, and Maillard reaction was followed photocolorimetrically. In NS systems, the Maillard reaction rate was inversely dependent with the increase of RH. These results are due to a heterogeneous distribution of water and reactants within the starch matrix. In GS systems, the rate coefficient of the Maillard reaction increased up to RHs between 75% and 84% and then decreased at higher RH values. In this case, Maillard reaction rate could be related to the physical properties of the matrix: T _g, water sorption, and water mobility can be relevant tools to predict the Maillard reaction rate-dependence on water content.     

Inhomogeneous distribution of fat enhances the perception of fat-related sensory attributes in gelled foods

This study investigated the effect of the spatial distribution of fat on the perception of fat-related sensory attributes using a model system that consisted of layered agar/gelatin gels containing oil-in-water (O/W) emulsion droplets dispersed in the gel matrix. Four layers of gel varying in the amount of emulsion droplets were combined to prepare samples with homogeneous and inhomogeneous distributions of fat (emulsion droplets). The composition of the gels was optimized to obtain samples with comparable mechanical properties.     

Transformation of waterborne hybrid polymer particles into films: Morphology development and modeling

Films cast from multiphase polymer particles have the potential to combine the properties of their components synergistically. The properties of the film depend on the hybrid polymer architecture and the film morphology. However, how the polymer microstructure and particle morphology are transformed during film formation to determine the film morphology is not well understood. Here, using waterborne alkyd-acrylic nanocomposite particles in a case study, it was found that phase migration leading to the formation of aggregates occurred during film formation. A coarse-grained Monte Carlo model was developed to account for the effects of polymer microstructure and particle morphology on the morphology of the film. The model was validated by comparing its predictions with the observed effects, and then used to explore combinations of polymer microstructure and particle morphology not attainable with the system used as a case study. Significantly, the compatibility of the phases was found to have a greater influence than the morphology of the particles in determining the film structure.     

Structural Basis for the Functional Diversity of Centrins: A Focus on Calcium Sensing Properties and Target Recognition

Centrins are a family of small, EF hand-containing proteins that are found in all eukaryotes and are often complexed with centrosome-related structures. Since their discovery, centrins have attracted increasing interest due to their multiple, diverse cellular functions. Centrins are similar to calmodulin (CaM) in size, structure and domain organization, although in contrast to CaM, the majority of centrins possess at least one calcium (Ca²⁺) binding site that is non-functional, thus displaying large variance in Ca²⁺ sensing abilities that could support their functional versatility. In this review, we summarize current knowledge on centrins from both biophysical and structural perspectives with an emphasis on centrin-target interactions. In-depth analysis of the Ca²⁺ sensing properties of centrins and structures of centrins complexed with target proteins can provide useful insight into the mechanisms of the different functions of centrins and how these proteins contribute to the complexity of the Ca²⁺ signaling cascade. Moreover, it can help to better understand the functional redundancy of centrin isoforms and centrin-binding proteins.     

What Do We Have to Know about PD-L1 Expression in Prostate Cancer? A Systematic Literature Review. Part 3: PD-L1, Intracellular Signaling Pathways and Tumor Microenvironment

The tumor microenvironment (TME) includes immune (T, B, NK, dendritic), stromal, mesenchymal, endothelial, adipocytic cells, extracellular matrix, and cytokines/chemokines/soluble factors regulating various intracellular signaling pathways (ISP) in tumor cells. TME influences the survival/progression of prostate cancer (PC), enabling tumor cell immune-evasion also through the activation of the PD-1/PD-L1 axis. We have performed a systematic literature review according to the PRISMA guidelines, to investigate how the PD-1/PD-L1 pathway is influenced by TME and ISPs. Tumor immune-escape mechanisms include suppression/exhaustion of tumor infiltrating cytotoxic T lymphocytes, inhibition of tumor suppressive NK cells, increase in immune-suppressive immune cells (regulatory T, M2 macrophagic, myeloid-derived suppressor, dendritic, stromal, and adipocytic cells). IFN-γ (the most investigated factor), TGF-β, TNF-α, IL-6, IL-17, IL-15, IL-27, complement factor C5a, and other soluble molecules secreted by TME components (and sometimes increased in patients’ serum), as well as and hypoxia, influenced the regulation of PD-L1. Experimental studies using human and mouse PC cell lines (derived from either androgen-sensitive or androgen-resistant tumors) revealed that the intracellular ERK/MEK, Akt-mTOR, NF-kB, WNT and JAK/STAT pathways were involved in PD-L1 upregulation in PC. Blocking the PD-1/PD-L1 signaling by using immunotherapy drugs can prevent tumor immune-escape, increasing the anti-tumor activity of immune cells.