N-Nitrosamine Analysis in Beer Using Thermal Desorption Injection Coupled with GC-TEA

A fast and sensitive method is described for determining a mixture of volatile N-nitrosamines in beer and other malt products. It consists of direct extraction of the sample with dichloromethane, volume reduction, cleanup by trapping volatiles onto Tenax-TA, and thermal desorption injection into a capillary gas chromatograph-thermal energy analyzer. Average recovery of N-nitrosodimethylamine added to beer ranged from 70 to 81%. N-Nitrosodimethylamine and N-nitrosopyrrolidine were detected in 10 samples of various domestic and imported beers analyzed. Total volatile N-nitrosamine concentrations ranged from 0.03 to 1.10 ppb in beer. Minimum detection limit of the method was 0.01 ppb for N-nitrosodimethylamine, a 10-fold increase in sensitivity compared to other similar methods.     

Carrot Dehydration—Optimization Process Studies on the Explosion-Puffing Process

A carrot dehydration process that includes the unique continuous explosion-puffing system (CEPS) is described. A drying study included moisture distribution throughout a two-stage pilot scale dryer as well as bed temperature during first stage drying. Shrinkage losses of carrots by two dehydration methods were investigated, and volume differences were obtained. Measurements of dried carrot properties such as bulk density, color, nonenzymatic browning, rehydration, and disintegration were used to determine optimum operating pressure, temperature, and feed moisture for CEPS. Response surfaces developed from these properties were used simultaneously to establish a constrained optimum.     

Burial grounds’ impact on groundwater and public health: an overview

The most common practice for disposal of dead bodies is inhumation in soil, which favours interactions with the surrounding environment and returns nutrients to the life cycle. However, when the burial ground is located where hydrogeological, geological and climatic conditions are not favourable to the process, contamination of soils and groundwater may occur, and decomposition may be inhibited, leading to social, economic and political problems. The most critical parameters when assessing the pollution potential of a burial ground are inhumation depth, geological formation, depth of the water table, density of inhumations, soil type and climate. Considering that, this paper presents an overview of the potential threat that cemeteries can pose, analysing and discussing the influence of the main variables causing environmental impacts and public health risks.     

228Ra in cow’s milk from an anomalous region of Pernambuco-Brazil

The counties of Pedra and Venturosa have one of the largest natural radioactive occurrences of Brazil. The large farms producing milk in the state of Pernambuco are located in these counties. The forage plants cultivated on those farms have high concentrations of ²²⁸Ra, a naturally occurring descending radionuclide from the ²³²Th series. The ²²⁸Ra is transferred to the forage plants, and once ingested by the lactating cow, this radionuclide is rapidly transferred to the milk. Thus, milk intake is an important route for ²²⁸Ra of incorporation by the human consumer and may induce the appearance of bone sarcoma. Accordingly, the aim of the present study was to determine the concentrations of ²²⁸Ra in milk produced in the Pedra and Venturosa farms, in order to estimate the risk of ingestion in the local population. The ²²⁸Ra was determined by actin-228 (²²⁸Ac) using the radiochemical technique of barium sulphate precipitate (BaSO₄). The milk samples had concentrations of ²²⁸Ra ranging from 61 to 1338 mBq.l^?1, which corresponded to the cumulative equivalent dose ranging from 0.04 to 0.1 Sv. Although the doses were low, regulatory and protective measures should be taken to study the radiotoxic effects of ²²⁸Ra in subjects in the public.     

Isothermal crystallization kinetics and morphology of PP/TiO2 nanocomposites using titanium n‐butoxide precursor

This study investigates the influence of the addition of TiO₂, obtained by hydrolysis–condensation reaction of titanium dioxide precursors, on the kinetics of polypropylene (PP) isothermal crystallization. The dispersion of nanoparticle and its relation to the degree of crystallinity by XRD was also investigated. The results indicated that the addition of the TiO₂ increased the degree of crystallinity of PP and its crystallization temperature. Likewise, the nucleation and crystal growth processes were also affected, as indicated by the TEM morphology, the Avrami kinetic model, and the optical microscopy, in which a nucleation effect was detected. POLYM. COMPOS. 36:517–526, 2015. © 2014 Society of Plastics Engineers     

COVID-19 and Lung Mast Cells: The Kallikrein–Kinin Activation Pathway

Mast cells (MCs) have relevant participation in inflammatory and vascular hyperpermeability events, responsible for the action of the kallikrein–kinin system (KKS), that affect patients inflicted by the severe form of COVID-19. Given a higher number of activated MCs present in COVID-19 patients and their association with vascular hyperpermeability events, we investigated the factors that lead to the activation and degranulation of these cells and their harmful effects on the alveolar septum environment provided by the action of its mediators. Therefore, the pyroptotic processes throughout caspase-1 (CASP-1) and alarmin interleukin-33 (IL-33) secretion were investigated, along with the immunoexpression of angiotensin-converting enzyme 2 (ACE2), bradykinin receptor B1 (B1R) and bradykinin receptor B2 (B2R) on post-mortem lung samples from 24 patients affected by COVID-19. The results were compared to 10 patients affected by H1N1pdm09 and 11 control patients. As a result of the inflammatory processes induced by SARS-CoV-2, the activation by immunoglobulin E (IgE) and degranulation of tryptase, as well as Toluidine Blue metachromatic (TB)-stained MCs of the interstitial and perivascular regions of the same groups were also counted. An increased immunoexpression of the tissue biomarkers CASP-1, IL-33, ACE2, B1R and B2R was observed in the alveolar septum of the COVID-19 patients, associated with a higher density of IgE⁺ MCs, tryptase⁺ MCs and TB-stained MCs, in addition to the presence of intra-alveolar edema. These findings suggest the direct correlation of MCs with vascular hyperpermeability, edema and diffuse alveolar damage (DAD) events that affect patients with a severe form of this disease. The role of KKS activation in events involving the exacerbated increase in vascular permeability and its direct link with the conditions that precede intra-alveolar edema, and the consequent DAD, is evidenced. Therapy with drugs that inhibit the activation/degranulation of MCs can prevent the worsening of the prognosis and provide a better outcome for the patient.     

Composites based on high-density polyethylene,polylactide and calcium carbonate: effect of calcium carbonate nanoparticles as co-compatibilizers

Polymer Bulletin - Investigating the compatibility mechanism of hybrid composites based on two polymers and one mineral nanofiller is a challenge that needs to be better understood. This study...     

Methylmercury Causes Neurodegeneration and Downregulation of Myelin Basic Protein in the Spinal Cord of Offspring Rats after Maternal Exposure

Methylmercury (MeHg) is one of the most dangerous toxic pollutants spread throughout the earth. Chronic MeHg intoxication by contaminated food ingestion is the most common threat to human health, including impairment to the developing fetus. The present study aims at investigating the effects of maternal exposure to MeHg during gestation and lactation on the spinal cord of offspring. Pregnant rats received oral doses of MeHg (40 μg/kg/day) over a period of 42 days (21 gestation and 21 lactation). Control animals received the vehicle only. Total mercury concentration was measured in blood samples from offspring collected at the 41st postnatal day. Counting of motor neurons and immunoreactivity for myelin basic protein (MBP) were assessed in the spinal cords in both control and MeHg-intoxicated animals. Our results showed that MeHg promoted an increase in blood Hg levels. In addition, it caused a reduction in the number of spinal cord motor neurons as well as decreased MBP immunoreactivity in the cervical, thoracic and lumbar segments. Our present findings suggest that MeHg intoxication during rat pregnancy and lactation is associated with a pattern of motor neuron degeneration and downregulation of myelin basic protein in different segments of a developing spinal cord. Further studies are needed to establish the effect of MeHg intoxication in both young and adult rats.     

Effect of preheating on potato texture

Preheating potatoes at 50 to 80°C has a firming effect on the cooked potato tissue. This effect is particularly pronounced at a preheating temperature of 60 to 70°C followed by cooling. Several theories have been presented in the literature to explain this firming effect: retrogradation of starch, leaching of amylose, stabilization of the middle lamellae and cell walls by the activation of the pectin methylesterase (PME) enzyme, and by the release of calcium from gelatinized starch and the formation of calcium bridges between pectin molecules. Most probably, none of these theories alone can explain the phenomenon and more than one mechanism seems to be involved. Some of these mechanisms seem to be interdependent. As an example, calcium could be considered as a link all the way through release after starch gelatinization to cross‐linking pectin substances in the cell wall and the middle lamellae, which has been demethylated by the PME enzyme. More research and “clear cut” experiments are needed in order to elucidate the role of each mechanism, especially which of them is the main contributor to the process of firming. Most probably, the calcium‐pectin‐PME mechanism plays a secondary role, that is, it only retards the collapse of the tissue structure that would otherwise occur during the final heating without preheating, and it is not the main factor of firmness.