Improved heat stability by whey protein–surfactant interaction

One of the main changes that occur during heat treatment of milk is whey protein denaturation, which in its turn may lead to protein aggregation and gelation. In this contribution, the effect of lysophospholipids, the main components of lysolecithins, as well as alternative surfactants, on heat-induced whey protein aggregation has been studied. Hereby, attention was paid to the relation between polar lipid molecular structure (e.g. effect of alkyl chain length, effect of polar head group) and heat-stabilising properties. Residual protein determination in the supernatant obtained after centrifugation of heated whey protein solutions learned that whey protein aggregation was at least partly prevented in the presence of surfactants. As the short alkyl chain lysophospholipids were particularly effective heat stabilisers, hydrophilic surfactants seemed to be most effective, which may be ascribed to their higher critical aggregation concentration. Upon more severe heat treatment, protein aggregation was probed either in-situ by oscillatory rheology, or ex-situ by yield rheometry. As some surfactants significantly reduced the gel strength, or even prevented heat-induced gel formation, these experiments corroborated the heat-stabilising effect of hydrophilic surfactants. Nuclear Magnetic Resonance (NMR) enabled a more direct evaluation of the protein–surfactant interaction. A strong hydrophobic interaction between small molecular weight surfactants and whey proteins became obvious from the chemical shift of the surfactant hydrophobic groups in the NMR spectrum and could be quantified by pulsed field gradient NMR (pfg-NMR) diffusiometry. The results indicated that protein–surfactant interaction did not occur upon thermal denaturation, but already took place at room temperature. However, the effect of this interaction became mainly obvious during thermal treatment.     

Failure mechanisms in single-point incremental forming of metals

The last years saw the development of two different views on how failure develops in single-point incremental forming (SPIF). Today, researchers are split between those claiming that fracture is always preceded by necking and those considering that fracture occurs with suppression of necking. Each of these views is supported by convincing experimental and theoretical arguments that are available in the literature. This paper revisits failure in SPIF and presents a new level of understanding on the influence of process variables such as the tool radius that assists the authors to propose a new unified view on formability limits and development of fracture. The unified view conciliates the aforementioned different explanations on the role of necking in fracture and is consistent with the experimental observations that have been reported in the past years. The work is performed on aluminium AA1050-H111 sheets and involves independent determination of formability limits by necking and fracture using tensile and hydraulic bulge tests in conjunction with SPIF of benchmark shapes under laboratory conditions.     

Box–Behnken factorial design study of the variables affecting metal electrodeposition in membraneless fluidized bed electrodes

BACKGROUND: Heavy metal removal from industrial wastewaters has been studied intensively since it is well known that they can cause severe problems to human health and aquatic life, even at very low concentrations. Traditional precipitation or adsorption technologies only transfer the problem to the solid phase, therefore new technologies, such as electrodeposition using fluidized bed electrodes (FBE), have been considered to avoid contamination. RESULTS: Copper electrodeposition from diluted solutions was carried out using a membraneless FBE. The supporting electrolyte concentration (C_s) was the main variable affecting the current efficiency (CE), energy consumption (EC), and space‐time yield (Y). Although it does not change the response surface morphology, increasing C_s there was an important improvement of CE, Y, and EC. The effects of current and bed expansion are much more complex, since an interaction effect between these two variables was verified. Considering only the region of active kinetic control, copper can be optimally recovered with CE > 90%, Y ～93 kg h^?1 m^?3, and EC ～3.2 kWh kg^?1 by applying the highest levels of the independent variables. CONCLUSIONS: The results suggest that electrodeposition using a membraneless FBE is an excellent method for the treatment of effluents contaminated with copper or other metals. © 2012 Society of Chemical Industry     

Relationship between tonsils and mandibular lymph nodes concerning Salmonella sp. infection

Pigs can be orally infected with Salmonella sp. that rapidly (in 30 min) invade the tonsils and subsequently, through lymphatic spread, reach the mandibular lymph nodes. These infected lymphatic tissues may constitute an important reservoir of Salmonella sp. playing a crucial role as a source of contamination during the slaughter process, promoting the introduction of Salmonella into the food chain.The main objective of this work was the study of Salmonella sp. occurrence in mandibular lymph nodes and in tonsils of slaughtered pigs, to define the level of association between these two lymphatic tissues concerning Salmonella infection. For this purpose, RFLP-PFGE was used to identify the clonal relationships between Salmonella sp. strains isolated from the mandibular lymph nodes and from the tonsils. The study revealed the presence of Salmonella in 12.9% of the mandibular lymph nodes and in 9.9% of the tonsils, from which 70% were associated to positive mandibular lymph nodes. This association emphasizes the importance of these lymphatic tissues as Salmonella sp. carriers, and alerts to the fact that particular and additional measures, in the context of the new European Regulation, should be implemented during the slaughter process in order to reduce the level of Salmonella sp. contamination.     

Modeling Rett Syndrome with Human Pluripotent Stem Cells: Mechanistic Outcomes and Future Clinical Perspectives

Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations in the gene encoding the methyl-CpG-binding protein 2 (MeCP2). Among many different roles, MeCP2 has a high phenotypic impact during the different stages of brain development. Thus, it is essential to intensively investigate the function of MeCP2, and its regulated targets, to better understand the mechanisms of the disease and inspire the development of possible therapeutic strategies. Several animal models have greatly contributed to these studies, but more recently human pluripotent stem cells (hPSCs) have been providing a promising alternative for the study of RTT. The rapid evolution in the field of hPSC culture allowed first the development of 2D-based neuronal differentiation protocols, and more recently the generation of 3D human brain organoid models, a more complex approach that better recapitulates human neurodevelopment in vitro. Modeling RTT using these culture platforms, either with patient-specific human induced pluripotent stem cells (hiPSCs) or genetically-modified hPSCs, has certainly contributed to a better understanding of the onset of RTT and the disease phenotype, ultimately allowing the development of high throughput drugs screening tests for potential clinical translation. In this review, we first provide a brief summary of the main neurological features of RTT and the impact of MeCP2 mutations in the neuropathophysiology of this disease. Then, we provide a thorough revision of the more recent advances and future prospects of RTT modeling with human neural cells derived from hPSCs, obtained using both 2D and organoids culture systems, and its contribution for the current and future clinical trials for RTT.     

Effects of seasoning on the formation of heterocyclic amines and polycyclic aromatic hydrocarbons in meats: A meta-analysis

Cooking improves digestibility, palatability, and microbiological profile of meats, but can produce compounds with carcinogenic potential, such as heterocyclic amines (HAs) and polycyclic aromatic hydrocarbons (PAHs). It has been shown that the formation of these compounds in meats can be inhibited by spiced marinades, but there is a complexity to check and compare the results of isolated studies with so many variables involved. Thus, this work aimed to review studies that evaluated the effects of spices on the formation of HAs and PAHs in meats according to cooking techniques and spice type. A meta-analysis with a random effect model was conducted using response ratios (R) to identify and summarize previous results and answer the research question. The use of spices before frying (R* = 0.52), grilling (R* = 0.63), or roasting (R* = 0.74) meat, and spicing with garlic and onion (R* = 0.57), pepper (R* = 0.63), and other spices with phenolic compounds (R* = 0.63), decrease the formation of HAs and PAHs, due to the antioxidant and electron transfer capacity. In this article, we discuss how the improvement of culinary techniques with the dissemination of knowledge about meat preparation conditions is an effective strategy for reducing the formation and ingestion of HAs and PAHs; this is important due to the growing evidence about the association between meat consumption and chronic diseases. This is the first systematic review with meta-analysis about this topic and can guide industry, food services, and population to improve the safety associated with meat consumption.     

Double-Cubane [8Fe9S] Clusters: A Novel Nitrogenase-Related Cofactor in Biology

Three different types of electron-transferring metallo-ATPases are able to couple ATP hydrolysis to the reduction of low-potential metal sites, thereby energizing an electron. Besides the Fe-protein known from nitrogenase and homologous enzymes, two other kinds of ATPase with different scaffolds and cofactors are used to achieve a unidirectional, energetic, uphill electron transfer to either reduce inactive Co-corrinoid-containing proteins (RACE-type activators) or a second iron-sulfur cluster-containing enzyme of a unique radical enzymes family (archerases). We have found a new cofactor in the latter enzyme family, that is, a double-cubane cluster with two [4Fe4S] subclusters bridged by a sulfido ligand. An enzyme containing this cofactor catalyzes the ATP-dependent reduction of small molecules, including acetylene. Thus, enzymes containing the double-cubane cofactor are analogous in function and share some structural features with nitrogenases.     

Epigenetic Regulation of Pulmonary Arterial Hypertension-Induced Vascular and Right Ventricular Remodeling: New Opportunities?

Pulmonary artery hypertension (PAH) is a rare chronic disease with high impact on patients’ quality of life and currently no available cure. PAH is characterized by constant remodeling of the pulmonary artery by increased proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs), fibroblasts (FBs) and endothelial cells (ECs). This remodeling eventually leads to increased pressure in the right ventricle (RV) and subsequent right ventricle hypertrophy (RVH) which, when left untreated, progresses into right ventricle failure (RVF). PAH can not only originate from heritable mutations, but also develop as a consequence of congenital heart disease, exposure to drugs or toxins, HIV, connective tissue disease or be idiopathic. While much attention was drawn into investigating and developing therapies related to the most well understood signaling pathways in PAH, in the last decade, a shift towards understanding the epigenetic mechanisms driving the disease occurred. In this review, we reflect on the different epigenetic regulatory factors that are associated with the pathology of RV remodeling, and on their relevance towards a better understanding of the disease and subsequently, the development of new and more efficient therapeutic strategies.     

Microparticulated Hydrochlorothiazide Solid Dispersion: Enhancing Dissolution Properties via Spray Drying

The aim of the present study was to obtain microparticles of hydrochlorothiazide, a diuretic drug that practically insoluble in water, by spray drying and to investigate the influence of process parameters using a three-level, three-factor Box-Behnken design. Process yields, moisture content, particle size, flowability, and solubility were used to evaluate the spray-dried microparticles. The data were analyzed by response surface methodology using analysis of variance. The independent variables studied were outlet temperature, atomization pressure, and drug content. The formulations were prepared using polyvinylpyrrolidone and colloidal silicon dioxide as the hydrophilic carrier and drying aid, respectively. The microparticle yield ranged from 18.15 to 59.02% and resulted in adequate flow (17 to 32°), moisture content between 2.52 to 6.18%, and mean particle size from 45 to 59 µm. The analysis of variance showed that the factors studied influenced the yields, moisture content, angle of repose, and solubility. Thermal analysis and X-ray diffractometry evidenced no drug interactions or chemical modifications. Photomicrographs obtained by scanning electron microscopy showed spherical particles. The solubility and dissolution rates of hydrochlorothiazide were remarkably improved when compared with pure drug. Therefore, the results confirmed the high potential of the spray-drying technique to obtain microparticulate hydrochlorothiazide with enhanced pharmaceutical and dissolution properties.