Behavior of selected micro and trace elements and organic matter in sediments of a freshwater system in south-east Brazil

The Cima Lake (CL) is a freshwater system located in the Northern Region of Rio de Janeiro State. It has a history of agricultural and cattle raising activities. The original Atlantic forest has been deforested and replaced by pasture and sugar cane crops. The objectives of this study were to understand the vertical distribution of organic matter and heavy metals associated with lacustrine sediments and to evaluate the influence of land use on the relative contribution of organic matter sources and heavy metals to the lake sediments. For these purposes, sediment cores were collected at three stations: inlet, center and outlet of the CL. It was possible to date sediments buried over the last 150 years. The results revealed that the changes caused by human intervention in the CL watershed influenced sediment sources and composition, and led to increasing sedimentation rates over the past century. The (C/N)a ratios ranged between 5.7 and 47.4 and showed that between the 1950s and 1960s there was an alteration in the sources of organic matter to CL sediments, indicating a period marked by the expansion of sugar-cane and alcohol industries in the region and an intense deforestation in the lake watershed. The heavy metal concentrations obtained in this study were similar to those described for natural systems, in spite of the system being influenced by anthropogenic sources. The Me+/Ti ratios indicate the existence of human intervention processes in the lake, showing that the origin of metals is not only from natural processes.     

Biochemical and morphological alterations of the extracellular matrix of chicken calcaneal tendon during maturation

The region in tendons that surrounds bone extremities adapts to compression forces, developing a fibrocartilaginous structure. During maturation, changes occur in the amount and organization of macromolecules of the extracellular matrix of tendons, changing the tissue morphology. To study the effect of maturation on tendons, Pedrês chickens were sacrificed at 1, 5, and 8 months old and had the calcaneal tendon (CT) divided into proximal region, submitted to tension/compression forces ( p ), and distal region submitted to tension force ( d ). Morphological analysis of the p region showed the presence of fibrocartilage in all ages. In the central part of the fibrocartilage, near a diminishment of the metachromasy, there was also a development of a probable fat pad that increased with the maturation. The activity of MMP‐2 and MMP‐9 was higher at 5 and 8 months old, in both regions, compared with 1‐month‐old animals. In SDS‐PAGE analysis, components with electrophoretic migration similar to decorin and fibromodulin increased with maturation, particularly in the d region. The Western blotting confirmed the increased amount of fibromodulin with maturation. In conclusion, our results show that process of maturation leads to the appearance of a probable fat pad in the center of the fibrocartilage of CT, with a reduced amount of glycosaminoglycans and an increased activity of MMPs. Microsc. Res. Tech. 78:949–957, 2015. © 2015 Wiley Periodicals, Inc.     

CO2 laser emission modes to control enamel erosion

Considering the importance and prevalence of dental erosion, the aim of this in vitro study was to evaluate the influence of different modes of pulse emission of CO₂ laser associated or not to acidulated phosphate fluoride (APF) 1.23% gel, in controlling enamel erosion by profilometry. Ninety‐six fragments of bovine enamel were flattened and polished, and the specimens were subjected to initial erosive challenge with hydrochloric acid (pH = 2). Specimens were randomly assigned according to surface treatment: APF 1.23% gel and gel without fluoride (control), and subdivided according to the modes of pulse CO₂ laser irradiation: no irradiation (control), continuous, ultrapulse, and repeated pulse (n = 12). After surface treatment, further erosive challenges were performed for 5 days, 4 × 2 min/day. Enamel structure loss was quantitatively determined by a profilometer, after surface treatment and after 5 days of erosive challenges. Two‐away ANOVA revealed a significant difference between the pulse emission mode of the CO₂ laser and the presence of fluoride (P ≤ 0.05). The Duncan's test showed that CO₂ laser irradiation in continuous mode and the specimens only received fluoride, promoted lower enamel loss than that other treatments. A lower dissolution of the enamel prisms was observed when it was irradiated with CO₂ laser in continuous mode compared other groups. It can be concluded that CO₂ laser irradiation in continuous mode was the most effective to control the enamel structure loss submitted to erosive challenges with hydrochloric acid. Microsc. Res. Tech. 78:654–659, 2015. © 2015 Wiley Periodicals, Inc.     

Major Peptides from Amaranth (Amaranthus cruentus) Protein Inhibit HMG-CoA Reductase Activity

The objective of this study was to identify the major peptides generated by the in vitro hydrolysis of Amaranthus cruentus protein and to verify the effect of these peptides on the activity of 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA reductase), a key enzyme in cholesterol biosynthesis. A protein isolate was prepared, and an enzymatic hydrolysis that simulated the in vivo digestion of the protein was performed. After hydrolysis, the peptide mixture was filtered through a 3 kDa membrane. The peptide profile of this mixture was determined by reversed phase high performance chromatography (RP-HPLC), and the peptide identification was performed by LC-ESI MS/MS. Three major peptides under 3 kDa were detected, corresponding to more than 90% of the peptides of similar size produced by enzymatic hydrolysis. The sequences identified were GGV, IVG or LVG and VGVI or VGVL. These peptides had not yet been described for amaranth protein nor are they present in known sequences of amaranth grain protein, except LVG, which can be found in amaranth α‑amylase. Their ability to inhibit the activity of HMG-CoA reductase was determined, and we found that the sequences GGV, IVG, and VGVL, significantly inhibited this enzyme, suggesting a possible hypocholesterolemic effect.     

Evaluation of an analytical methodology using QuEChERS and GC-SQ/MS for the investigation of the level of pesticide residues in Brazilian melons

A multiresidue method based on the sample preparation by modified QuEChERS and detection by gas chromatography coupled to single quadruple mass spectrometers (GC-SQ/MS) was used for the analysis of 35 multiclass pesticides in melons (Cucumis melo inodorus) produced in Ceara-Brazil. The rates of recovery for pesticides studied were satisfactory (except for the etridiazole), ranging from 85% to 117% with a relative standard deviation (RSD) of less than 15%, at concentrations between 0.05 and 0.20 mg kg⁻¹. The limit of quantification (LOQ) for most compounds was below the MRLs established in Brazil. The combined relative uncertainty (Uc) and expanded uncertainty (Ue) was determined using repeatability, recovery and calibration curves data for each pesticide. Analysis of commercial melons samples revealed the presence of pesticides bifenthrin and imazalil at levels below the MRLs established by ANVISA, EU and USEPA.     

Road environment modeling using robust perspective analysis and recursive Bayesian segmentation

Recently, vision-based advanced driver-assistance systems (ADAS) have received a new increased interest to enhance driving safety. In particular, due to its high performance–cost ratio, mono-camera systems are arising as the main focus of this field of work. In this paper we present a novel on-board road modeling and vehicle detection system, which is a part of the result of the European I-WAY project. The system relies on a robust estimation of the perspective of the scene, which adapts to the dynamics of the vehicle and generates a stabilized rectified image of the road plane. This rectified plane is used by a recursive Bayesian classifier, which classifies pixels as belonging to different classes corresponding to the elements of interest of the scenario. This stage works as an intermediate layer that isolates subsequent modules since it absorbs the inherent variability of the scene. The system has been tested on-road, in different scenarios, including varied illumination and adverse weather conditions, and the results have been proved to be remarkable even for such complex scenarios.     

Listeria monocytogenes in ready-to-eat,sliced, cooked ham and salami products,marketed in the city of São Paulo,Brazil: Occurrence,quantification, and serotyping

The preference for ready-to-eat sliced foods may pose an increased risk for food-borne diseases, and a major concern is the presence of Listeria monocytogenes. L. monocytogenes was assessed in two types of products: cooked ham and salami. One hundred and thirty samples of each product were acquired in retail shops in the city of São Paulo and submitted to laboratory analysis. The rate of positives was significantly higher in salami samples than in ham samples (6.2% and 0.8%, respectively). L. monocytogenes counts in salami samples varied between <10 and 1900 colony-forming units per gram (CFU/g). The serotypes found in both products were as follows, according to incidence: 4b (37.5%), 1/2b (25%), 3b (25%), and 1/2c (12.5%). Based on the results of the present study, the authors suggest that the risk of listeriosis resulting from the consumption of salami is higher than that associated with the consumption of cooked ham.     

Optimal mechanical spindle speeder gearbox design for high-speed machining

There are different solutions to upgrade a conventional machine tool to high-speed machining (HSM). One of the cheapest solutions is the use of mechanical spindle speeders. Mechanical spindle speeders allows the increase of the speed of a machine tool by means of a multiplier gearbox, and they have been successfully used in a variety of machining processes, such as drilling, milling, tapping and even grinding. They are mainly used in the mould and die industry, since they provide an effective solution for upgrading an existing lower speed machine tool. In this work, the design of the planetary gear trains (PGTs) used in all of the mechanical spindle speeders marketed nowadays is optimised by minimising the volume and the kinetic energy of these gearboxes, since their functionality depends directly on these two criteria. In the authors’ opinion, the results can be of great interest for spindle speeder manufacturers.     

An agent-based solution of Lagrange equations for adsorption processes

A simple numerical method for solving the rate equation of adsorption processes is presented. The method starts with the mass balance for the fluid phase in its lagrangian form and the corresponding equation for the solid phase; these equations are then used to specify the governing interaction rules of discrete elements, dubbed agents. In the calculation code, ALEAP, the calculation is carried out as a series of cycles in which the agents, representing the adsorption process, interact according to these rules. In this paper we present the results obtained for linear isotherms from no transfer to high transfer rate. The method is surprisingly efficient for finding the right solution for the problem of dispersion with no adsorption and superior, in terms of computer processing time, to other methods for the simulation of the adsorption process with linear or non-linear isotherms.