Chemical composition of rainwater at a coastal town on the southwest of Europe: what changes in 20 years?

Rainwater was collected at the Portuguese west coast between September 2008 and September 2009, and analysed for pH, conductivity, and Cl⁻, NO₃⁻, SO₄²⁻, and NH₄⁺ concentrations. Results of rainwater chemical composition were compared with those obtained at the same site between 1986 and 1989. In both collection periods rainwater was predominantly (≈ 80%) associated to oceanic air masses. The rainwater concentration of H⁺ was in the same range as twenty years ago. A clear decrease of non sea salt sulphate (NSS-SO₄²⁻) was observed in 2008-2009 relatively to 1986-1989, not only in samples with origin in central and northern Europe, but also in samples from Atlantic Ocean and Mediterranean. This decrease indicates that SO₂ emissions were reduced, which may be due to a lower content of sulphur in oil by-products. A decrease was also observed in NH₄⁺ concentration in 2008-2009. On the contrary an increase of NO₃⁻ concentration was observed for samples of all origins in 2008-2009 relatively to 1986-1989, which was particularly high (more than 3 fold) for samples with origin in Atlantic Ocean, suggesting the incorporation of this ion by rainout at the sampling site. The contribution of local sources is indeed suggested by the moderate negative correlation of NH₄⁺, NO₃⁻ and NSS-SO₄²⁻ with rainwater volume. The high increase of NO₃⁻ concentration can be attributed to the increase of local vehicular and industrial emissions in the sampling area.     

Computational Analysis of SAM Analogs as Methyltransferase Inhibitors of nsp16/nsp10 Complex from SARS-CoV-2

Methyltransferases (MTases) enzymes, responsible for RNA capping into severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), are emerging important targets for the design of new anti-SARS-CoV-2 agents. Here, analogs of S-adenosylmethionine (SAM), obtained from the bioisosteric substitution of the sulfonium and amino acid groups, were evaluated by rigorous computational modeling techniques such as molecular dynamics (MD) simulations followed by relative binding free analysis against nsp16/nsp10 complex from SARS-CoV-2. The most potent inhibitor (2a) shows the lowest binding free energy (–58.75 Kcal/mol) and more potency than Sinefungin (SFG) (–39.8 Kcal/mol), a pan-MTase inhibitor, which agrees with experimental observations. Besides, our results suggest that the total binding free energy of each evaluated SAM analog is driven by van der Waals interactions which can explain their poor cell permeability, as observed in experimental essays. Overall, we provide a structural and energetic analysis for the inhibition of the nsp16/nsp10 complex involving the evaluated SAM analogs as potential inhibitors.     

Salmonella cross-contamination in swine abattoirs in Portugal: Carcasses, meat and meat handlers

In this study the occurrence of Salmonella in swine, pork meat and meat handlers along with their clonal relatedness is evaluated at abattoir level. Samples from the lymph nodes, carcass surface and meat of 100 pigs and 45 meat handlers were collected in eight abattoirs (July 2007-August 2008). Salmonella isolates were serotyped and genotyped by pulsed-field gel electrophoresis (PFGE). From the pigs tested, 42 produced at least one positive sample. A relatively high frequency of Salmonella occurrence was found in the ileoceacal lymph node samples (26.0%), followed by carcass (16.0%) and meat samples (14.0%). However, ileoceacal lymph nodes that test positive for Salmonella are not found to be a predictor of positive test results further on in the process. Besides the slaughterhouse environment, meat handlers were identified as a possible source of subsequent contamination, with 9.3% of the sample testing positive. Diverse Salmonella enterica serotypes were detected, mainly S. Typhimurium and the monophasic variant S. 4,[5],12:i:-, but also S. Derby, S. Rissen, S. Mbandaka, S. London, S. Give, S. Enteritidis and S. Sandiego, in total corresponding to 17 PFGE types. Our results demonstrate that besides a high level of Salmonella swine contamination at pre-harvest level, slaughtering, dressing, cutting and deboning operations are contributing to the occurrence of clinically relevant clones (e.g. S. Typhimurium DT104 and S. 4,[5],12:i:-) in pork products. This study also highlights the possibility of an ongoing Salmonella community being spread by abattoir workers.     

Parallelization of Full Search Motion Estimation Algorithm for Parallel and Distributed Platforms

This work presents an efficient method to map the Full Search algorithm for Motion Estimation (ME) onto General Purpose Graphic Processing Unit (GPGPU) architectures using Compute Unified Device Architecture (CUDA) programming model. Our method jointly exploits the massive parallelism available in current GPGPU devices and the parallelism potential of Full Search algorithm. Our main goal is to evaluate the feasibility of video codecs implementation using GPGPUs and its advantages and drawbacks compared to other platforms. Therefore, for comparison reasons, three solutions were developed using distinct programming paradigms for distinct underlying hardware architectures: (i) a sequential solution for general-purpose processor (GPP); (ii) a parallel solution for multi-core GPP using OpenMP library; (iii) a distributed solution for cluster/grid machines using Message Passing Interface (MPI) library. The CUDA-based solution for GPGPUs achieves speed-up compatible to the indicated by the theoretical model for different search areas. Our GPGPU Full Search Motion Estimation provides 2×, 20× and 1664× speed-up when compared to MPI, OpenMP and sequential implementations, respectively. Compared to state-of-the-art, our solution reaches up to 17× speed-up.     

TUIs vs. GUIs: comparing the learning potential with preschoolers

In an effort to better understand the learning potential of a tangible interface, we conducted a comparison study between a tangible and a traditional graphical user interface for teaching preschoolers (In Portugal, children enter preschool at the age of three and they attend it till entering school, normally at the age of six) about good oral hygiene. The study was carried with two groups of children aged 4 to 5 years. Questionnaires to parents, children’s drawings, and interviews were used for data collection and analysis and revealed important indicators about children’s change of attitude, involvement, and preferences for the interfaces. The questionnaires showed a remarkable change of attitude toward tooth brushing in the children that interacted with the tangible interface; particularly children’s motivation increased significantly. Children’s drawings were used to assess their degree of involvement with the interfaces. The drawings from the children that interacted with the tangible interface were very complete and detailed suggesting that the children felt actively involved with the experience. The results suggest that the tangible interface was capable of promoting a stronger and long-lasting involvement having a greater potential to engage children, therefore potentially promoting learning. Evaluation through drawing seems to be a promising method to work with preliterate children; however, it is advisable to use it together with other methods.     

Object-based land-cover change detection applied to Brazilian seasonal savannahs using geostatistical features

A new method for remote-sensing land-use/land-cover (LULC) change detection is proposed to eliminate the effects of forest phenology on classification results. This method is insensitive to spectral changes caused by vegetation seasonality and uses an object-based approach to extract geostatistical features from bitemporal Landsat TM (Thematic Mapper) images. We first create image objects by multiresolution segmentation to extract geostatistical features (semivariogram parameters and indices) and spectral information (average values) from NDVI (normalized difference vegetation index), acquired in the wet and dry seasons, as input data to train a Support Vector Machine algorithm. We also used the image difference traditional change-detection method to validate the effectiveness of the proposed method. We used two classes: (1) LULC change class and (2) seasonal change class. Using the most geostatistical features, the change detection results are considerably improved compared with the spectral features and image differencing technique. The highest accuracy was achieved by the sill (σ² overall variability) semivariogram parameter (95%) and the AFM (area first lag–first maximum) semivariogram index (88.33%), which were not affected by vegetation seasonality. The results indicate that the geostatistical context makes possible the use of bitemporal NDVI images to address the challenge of accurately detecting LULC changes in Brazilian seasonal savannahs, disregarding changes caused by phenological differences, without using a dense time series of remote-sensing images. The challenge of extracting accurate semivariogram curves from objects of long and narrow shapes requires further study, along with the relationship between the scale of segmentation and image spatial resolution, including the type of change and the initial land-cover class.     

Validation of measurement capabilities

The best measurement capabilities (BMCs) of laboratories are usually described at the Accreditation Certificates, for the calibrations they perform. The evaluation of these BMCs is carried out also by interlaboratory comparisons (ILCs), the proficiency testing schemes as described by the ISO Guide 43 and ISO 13528 standard. The National Metrology Institutes traditionally organize the ILCs for the National Accreditation Boards, providing the travelling standards, the reference(s) value(s) and the statistical analysis of the laboratories results. The goal of this article is to discuss the existing approaches for evaluation of ILCs and propose a basis for the validation of laboratories BMCs.     

Cover Image,Volume 98, Issue 3

The cover image, by Elizângela M Ogawa et al., is based on the Research Article Chemical profile of pineapple cv. Vitória in different maturation stages using electrospray ionization mass spectrometry, DOI: 10.1002/jsfa.8561 . Image Credit: José A Ventura.

     

Antioxidant, antiacetylcholinesterase and antimicrobial activities of Cymbopogon schoenanthus L. Spreng (lemon grass) from Tunisia

Aqueous extract, proanthocyanidin rich extract, and organic extracts of Cymbopogon schoenanthus L. Spreng (lemon grass) shoots from three different locations in South Tunisia were screened for their antioxidant, acetylcholinesterase and antimicrobial activities. In addition to the evaluation of these activities, the contents of flavonoids and total phenolic compounds were determined.Antioxidant activity measured by DPPH assay showed that the proanthocyanidin extract exhibited higher antioxidant activity than the aqueous extract. Extract concentration providing 50% inhibition (IC₅₀) ranged from 16.4 ± 6.8 μg/mL to 26.4 ± 6.8 μg/mL. The antioxidant activity was also determined using the β-carotene/linoleic acid bleaching test. The best results (IC₅₀ = 0.11 ± 0.10 mg/mL) were obtained with the proanthocyanidin extract of the plants collected from the desert region (Dhibat).The greatest acetylcholinesterase inhibitory activity (IC₅₀ = 0.23 ± 0.04 mg/mL) was exhibited by the ethyl acetate and methanol extracts of the plants collected from the mountainous region. It seems that extracts obtained with more polar solvents gave better results.The proanthocyanidin extracts showed a good antimicrobial activity against Streptococcus sobrinus at low concentration (MIC = 4 mg/mL). Therefore, these extracts could be used to prevent carious lesions by inhibiting S. sobrinus growth.     

Differentiation of port wines by appearance using a sensory panel: comparing free choice and conventional profiling

Received: 2 July 1999