A Kinetic Study on the Heat-Induced Changes of Whey Proteins Concentrate at Two pH Values

Whey protein concentrate (WPC) is used as food ingredients due to their commercially important functional properties. The effects of heat treatment on the components of milk are very important for the final product character, since they undergo modifications that affect sensorial and nutritional quality of milk. The heat-induced changes on dispersions of whey proteins concentrate were monitored by measurement of thiol availability, protein solubility, and turbidity at pH 6.6 and 7.5. The fractional conversion model was used to quantitatively describe the effect of different temperature–time combination on denaturation mechanism. The results demonstrate that heat-induced changes of WPC greatly influence their solubility, expressed as degree of denaturation at pH 4.6 and were related to the heating conditions. The denaturation mechanism involved a number of consecutive conformational changes in the molecules. A curvature in Arrhenius plots was observed around 75 °C, indicating changes in the reaction mechanism. The deflection of Arrhenius plot reflects the generally accepted two-step denaturation/aggregation process of whey proteins.     

Airflow inside an open ventilated system: Influence of operator’s arms or moving conveyor

This study deals with the influence of static and dynamic objects on the airflow (generated by a unidirectional air supply) inside an “open” ventilated system used in an agro-food production line. Firstly, the presence of operator’s arms, considered here as objects, leads to the appearance of recirculating zones under each arm. The influence of different positions of the static arms protected by gloves on the airflow organization has been studied. Secondly, modifications induced by the motion of a conveyor system or of moving arms on the airflow have been explored.In an experimental approach, airflow organization has been studied by visualization and by Particle Image Velocimetry for static cases and moving conveyor case.Numerical simulations were carried out using Computational Fluids Dynamics codes. Results obtained for moving gloves cases highlight the contribution of dynamic meshes tools, implemented in the CFD codes to make simulations of moving objects.     

Gangliosides as Biomarkers of Human Brain Diseases: Trends in Discovery and Characterization by High-Performance Mass Spectrometry

Gangliosides are effective biochemical markers of brain pathologies, being also in the focus of research as potential therapeutic targets. Accurate brain ganglioside mapping is an essential requirement for correlating the specificity of their composition with a certain pathological state and establishing a well-defined set of biomarkers. Among all bioanalytical methods conceived for this purpose, mass spectrometry (MS) has developed into one of the most valuable, due to the wealth and consistency of structural information provided. In this context, the present article reviews the achievements of MS in discovery and structural analysis of gangliosides associated with severe brain pathologies. The first part is dedicated to the contributions of MS in the assessment of ganglioside composition and role in the specific neurodegenerative disorders: Alzheimer’s and Parkinson’s diseases. A large subsequent section is devoted to cephalic disorders (CD), with an emphasis on the MS of gangliosides in anencephaly, the most common and severe disease in the CD spectrum. The last part is focused on the major accomplishments of MS-based methods in the discovery of ganglioside species, which are associated with primary and secondary brain tumors and may either facilitate an early diagnosis or represent target molecules for immunotherapy oriented against brain cancers.     

Brain Neurons during Physiological Aging: Morphological Features,Autophagic and Mitochondrial Contribution

Accumulating data suggest that the brain undergoes various changes during aging. Among them are loss of both white and gray matter, neurons and synapses degeneration, as well as oxidative, inflammatory, and biochemical changes. The above-mentioned age-related features are closely related to autophagy and mitochondria. Therefore, we aimed to reveal the most peculiar morphological features of brain nervous tissue and to characterize the expression of autophagy and mitochondrial immunohistochemical biomarkers in neurons of different human brain zones during aging. Counting the number of neurons as well as Microtubule-associated proteins 1A/1B light chain 3B (LC3B), Heat shock protein 70 (HSP70), Lysosome-associated membrane protein type 2A (LAMP2A), Alpha subunit of ATP synthase (ATP5A), and Parkinson disease protein 7 (DJ1) immunohistochemical staining were performed on FFPE samples of human prefrontal cortex, corpus striatum, and hippocampus obtained from autopsy. Statistical analysis revealed a loss of neurons in the studied elderly group in comparison to the young group. When the expression of macroautophagy (LC3B), chaperon-mediated autophagy (HSP70, LAMP2A), and mitochondrial respiratory chain complex V (ATP5A) markers for the young and elderly groups were compared, the latter was found to have a significantly higher rate of optical density, whilst there was no significance in DJ1 expression. These findings, while preliminary, suggest that both autophagy and mitochondria are involved in neuronal maintenance during aging and could indicate their potential role in adaptive mechanisms that occur in aging.     

The Ability of the Nitric Oxide Synthases Inhibitor T1023 to Selectively Protect the Non-Malignant Tissues

Previously, we showed that a nitric oxide synthase (NOS) inhibitor, compound T1023, induces transient hypoxia and prevents acute radiation syndrome (ARS) in mice. Significant efficacy (according to various tests, dose modifying factor (DMF)—1.6–1.9 against H-ARS/G-ARS) and safety in radioprotective doses (1/5–1/4 LD10) became the reason for testing its ability to prevent complications of tumor radiation therapy (RT). Research methods included studying T1023 effects on skin acute radiation reactions (RSR) in rats and mice without tumors and in tumor-bearing animals. The effects were evaluated using clinical, morphological and histological techniques as well as RTOG classification. T1023 administration prior to irradiation significantly limited the severity of acute RSR. This was due to a decrease in radiation alteration of the skin and underlying tissues, and the preservation of the functional activity of cell populations that are critical in the pathogenesis of radiation burn. The DMF values for T1023 for skin protection were 1.4–1.7. Moreover, its radioprotective effect was fully selective to normal tissues in RT models of solid tumors—T1023 reduced the severity of acute RSR and did not modify the antitumor effects of γ-radiation. The results indicate that T1023 can selectively protect the non-malignant tissues against γ-radiation due to hypoxic mechanism of action and potentiate opportunities of NOS inhibitors in RT complications prevention.     

Practical Application of the Probabilistic‐Statistical Model of the Suspension Separation in Hydrocyclones

An effective practical approach that allows not only a significant reduction in the scope of practical experiments in the course of studying suspension separation processes in hydrocyclones, but also makes it possible to assess the intensity of random components of the processes and define the interrelation between such components and hydrodynamics of flows in a hydrocyclone is presented. Within the frames of the developed probabilistic‐statistical model of suspension separation in hydrocyclones on the basis of statistical self‐similarity properties, a relationship was found between determined and random components of the processes. This allowed transitioning from three‐parameter probability density functions for suspension particles in hydrocyclones to two‐parameter functions; thus significantly improving the efficiency of practical application of the developed model.     

Autoproteolytic fragments are intermediates in the oligomerization/aggregation of the Parkinson's disease protein alpha-synuclein as revealed by ion mobility mass spectrometry

Gas-phase protein separation by ion mobility: With its ability to separate the Parkinson's disease protein α-synuclein and its autoproteolytic products-despite the small concentrations of the latter-ion-mobility MS has enabled the characterization of intermediate fragments in in vitro oligomerization-aggregation. In particular, a possible key fragment, the highly aggregating C-terminal fragment, αSyn(72-140), has been revealed.     

The encapsulation effect of UV molecular absorbers into biocompatible lipid nanoparticles

The efficiency of a cosmetic product depends not only on the active ingredients, but also on the carrier system devoted to improve its bioavailability. This article aims to encapsulate two couples of UV molecular absorbers, with a blocking action on both UV-A and UV-B domains, into efficient lipid nanoparticles. The effect of encapsulation on the specific properties such as sun protection factor and photostability behaviour has been demonstrated. The lipid nanoparticles with size range 30-350 nm and a polydispersity index between 0.217 and 0.244 are obtained using a modified high shear homogenisation method. The nanoparticles had spherical shapes with a single crystallisation form of lipid matrices characteristic for the least ordered crystal structure (α-form). The in vitro determination of photoprotection has led to high SPF ratings, with values of about 20, which assure a good photoprotection and filtering about 95% of UV radiation. The photoprotection effect after irradiation stage was observed to be increased more than twice compared to initial samples as a result of isomerisation phenomena. All the results have shown that good photoprotection effect and improved photostability could be obtained using such sunscreen couples, thus demonstrating that UV absorbers-solid lipid nanoparticles are promising carriers for cosmetic formulations.     

Organosoluble asymmetric aromatic polyamides bearing pendent phenoxy groups

This study focuses on the synthesis and characterization of new polyamides based on an aromatic asymmetric diamine‐containing phenoxy‐substituted benzophenone segment. Low‐temperature solution polycondensation reactions of this diamine with various aromatic diacid chlorides containing ether, hexafluoroisopropylidene or diphenylsilane groups resulted in polyamides with molecular weights in the range 102 900–113 200 g mol^?1. The structures of these monomers and the corresponding polymers were fully confirmed using elemental analysis and infrared and NMR spectroscopy. All polyamides were easily soluble at room temperature in polar aprotic solvents and even in less polar solvents such as tetrahydrofuran. The polymers showed excellent thermal stability, up to 385 °C, and displayed glass transition temperatures in the range 225–256 °C. All the polymers presented blue florescence upon irradiation with UV light and thus show promise for applications in electroluminescent devices. Copyright © 2011 Society of Chemical Industry