Ammonia traces detection based on photoacoustic spectroscopy for evaluating ammonia volatization from natural zeolites at typical crop field temperature

A Brazilian sedimentary zeolite-containing microporous material was characterized by determining its physical and chemical properties (surface area, pore volume, dinitrogen and ammonia desorption rates, oxide composition, and acid site characterization), and compared with two commercial natural zeolites. The characterization of these materials was performed using N₂ adsorption, X-ray fluorescence spectroscopy and temperature programmed desorption (TPD) techniques. Using photoacoustic spectroscopy, the performance of these microporous materials in the adsorption and delayed desorption of nitrogen-containing fertilizers was studied by monitoring the ammonia emission rate after their treatment with ammonium sulfate. Ammonia desorption curves were recorded under 30 °C and 60 °C, aiming to reproduce typical Brazilian cropfield temperature conditions.     

Volatiles and Tendency of Radical Formation of Cold‐Pressed Brazil Nut Oil During Ambient Storage

Cold‐pressed Brazil nut oil (BNO) is a value‐added nontimber forest coproduct of market interest, despite the lack of knowledge about its ambient storage stability. The objective of the present study was to investigate oxidative changes in BNO stored in clear and brown glass bottles under retail conditions with a focus on monitoring for the first time the formation of volatile aroma compounds (VAC), the depletion of tocopherol analogs, and the tendency of radical formation. VAC, whose formation continuously increased and correlated with storage time, were detected using headspace‐solid‐phase microextraction‐gas chromatography–mass spectrometry. Depletion of tocopherols was more pronounced for the oil stored in clear glass bottles and the content loss was higher for alpha‐tocopherol than for gamma‐tocopherol. Furthermore, the tendency of radical formation was detected using a spin‐trapping electron spin resonance spectroscopy method, which was demonstrated to be a simpler, faster, and less sample‐demanding tool to monitor the oxidative status of BNO stored under retail conditions and its results significantly correlated with those obtained using traditional methods for the determination of primary oxidation products. However, the simultaneous measurement of key off‐flavor volatiles is recommended for samples with unknown history.     

Preparation and characterization of chitosan/genipin/poly(N-vinyl-2-pyrrolidone) films for controlled release drugs

The study of the physicochemical and functional properties of chitosan films cross-linked with genipin and poly(N-vinyl-2-pyrrolidone) (PVP) was performed in this work. Cross-linked films were prepared by casting method from acetic acid solutions. The structure and physical properties of the films were analyzed by infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (¹³C NMR), differential scanning calorimetry (DSC) and mechanical testings. Propranolol hydrochloride was used like a model drug to determine the behavior of drug release from films. The drug release capacity was measured and compared with the degree of cross-linking, mechanical properties and swelling index.     

Chlamydia pneumoniae and Oxidative Stress in Cardiovascular Disease: State of the Art and Prevention Strategies

Chlamydia pneumoniae, a pathogenic bacteria responsible for respiratory tract infections, is known as the most implicated infectious agent in atherosclerotic cardiovascular diseases (CVDs). Accumulating evidence suggests that C. pneumoniae-induced oxidative stress may play a critical role in the pathogenesis of CVDs. Indeed, the overproduction of reactive oxygen species (ROS) within macrophages, endothelial cells, platelets and vascular smooth muscle cells (VSMCs) after C. pneumoniae exposure, has been shown to cause low density lipoprotein oxidation, foam cell formation, endothelial dysfunction, platelet adhesion and aggregation, and VSMC proliferation and migration, all responsible for the typical pathological changes of atherosclerotic plaque. The aim of this review is to improve our insight into C. pneumoniae-induced oxidative stress in order to suggest potential strategies for CVD prevention. Several antioxidants, acting on multi-enzymatic targets related to ROS production induced by C. pneumoniae, have been discussed. A future strategy for the prevention of C. pneumoniae-associated CVDs will be to target chlamydial HSP60, involved in oxidative stress.     

Total phenolic content and DPPH radical scavenging activity of lettuce (Lactuca sativa L.) grown in Colorado

Total phenolic content (TPC) and antioxidant capacity of lettuce were evaluated using the Folin-Ciocalteu method and DPPH assay, respectively, on 25 cultivars of lettuce, including leaf, romaine, crisphead, and butterhead types, cultivated over two harvest periods. Leaf lettuce possessed the highest TPC and highest DPPH scavenging ability, followed by romaine, butterhead and Batavia (crisphead subtype). Within a lettuce type, red pigmented lettuce cultivars had higher TPC and antioxidant capacity than did green cultivars grown under the same conditions. In addition, lettuce harvested in July possessed higher TPC and antioxidant capacity than did lettuce harvested in September, suggesting that environmental conditions could influence the phenolic content and antioxidant activity of lettuce. These results suggest that Colorado grown lettuce may serve as potential dietary sources of natural phenolic antioxidants.     

Microbiological Analyses of Dry and Slurry Yeasts for Brewing

Classical microbiological methods in association with molecular methods (DNA amplification, Temperature Gradient Gel Electrophoresis (TGGE) and Denaturing Gradient Gel Electrophoresis (DGGE) were used. These methods, developed to rapidly analyze microbial communities on the basis of sequence‐specific separation of DNA amplicons, allowed the detection of DNA differences in the amplicons tested and the identification of the strains analyzed by the comparison of unknown sequences with sequences of known species. TGGE allowed the comparison of the different Saccharomyces cerevisiae strains used in brewing while DGGE allowed the identification of lactic acid bacteria (LAB) in beer. These methods are a reliable tool for fast comparison of strains of Saccharomyces cerevisiae collected from different craft breweries where they were used as starters to check the presence of possible yeast contaminants in the brewing process and for rapid LAB identification.     

PCR‐TTGE and RAPD‐PCR Techniques to Analyze Saccharomyces cerevisiae and Saccharomyces carlsbergensis Isolated from Craft Beers

In the Friuli Venezia Giulia region (North East of Italy) the production of craft beers has been increasing constantly. Usually microbreweries use yeasts supplied by Italian or foreign industrial breweries for beer production. Yeast species are often not known, moreover the vitality, the viability, the physiological state and the number of generation are not known. To improve the quality of the final product it is important to evaluate the quality of the yeast strain used and the lactic acid bacteria contamination. Various molecular methods have been developed to compare genetic characteristics of yeast strains used in beer and wine production. The methods proposed in this work, PCR‐TTGE and RAPD‐PCR techniques, allow the comparison of specific DNA sequences to identify and/or characterize yeast strains. The molecular methods are faster than traditional methods and they allowed the identification of the strains analysed as S. cerevisiae and the intraspecies differentiation among yeast strains tested within 8 h after cell growth.     

Optimisation of Glucose Biosensors Based on Sol–Gel Entrapment and Prussian Blue-Modified Screen-Printed Electrodes for Real Food Analysis

In this study, we report the construction of amperometric screen-printed glucose biosensors for food analysis by using two procedures for Prussian Blue (PB) deposition and different membranes for enzymatic immobilisation. The comparison between the screen-printed electrodes modified with PB by electrochemical and chemical deposition showed higher analytical performance (detection limit of 1 μM, linear range from 0.5 to 500 μM and a sensitivity of 823 μA mM^?1 cm^?2) when the latter was employed. Then, the immobilisation of glucose oxidase (GOD) by silica sol–gel and polyvinyl alcohol (PVA) hydrogel was performed on electrochemically modified PB electrodes. The electrochemical response of two glucose biosensors was evaluated by flow injection analysis. Biosensors constructed by silica sol–gel entrapment showed a wider linear range (0.005–1 mM) and a detection limit (0.02 mM) that was 10-fold lower than using entrapped GOD in PVA. The selected glucose biosensor showed negligible interference from ascorbic acid when the Nafion membrane was used to cover the PB-modified electrode surface. Additionally, it exhibited an operating lifetime of 8 h under continuous glucose injections ranging from 0.01 to 2 mM. Finally, the biosensor was applied for specific determination of glucose in red and white wines, juices and dried fruit.     

Cell targeting with hybrid Qβ virus-like particles displaying epidermal growth factor

Structurally uniform protein nanoparticles derived from the self-assembly of viral capsid proteins are attractive platforms for the multivalent display of cell-targeting motifs for use in nanomedicine. Virus-based nanoparticles are of particular interest because the scaffold can be manipulated both genetically and chemically to simultaneously display targeting groups and carry a functional payload. Here, we displayed the human epidermal growth factor (EGF) on the exterior surface of bacteriophage Qβ as a C-terminal genetic fusion to the Qβ capsid protein. The co-assembly of wild-type Qβ and EGF-modified subunits resulted in structurally homogeneous nanoparticles displaying between 5 and 12 copies of EGF on their exterior surface. The particles were found to be amenable to bioconjugation by standard methods as well as the high-fidelity copper-catalyzed azide-alkyne cycloaddition reaction (CuAAC). Such chemical derivatization did not impair the ability of the particles to specifically interact with the EGF receptor. Additionally, the particle-displayed EGF remained biologically active promoting autophosphorylation of the EGF receptor and apoptosis of A431 cells. These results suggest that hybrid Qβ-EGF nanoparticles could be useful vehicles for targeted delivery of imaging and/or therapeutic agents.