Well-separated Group Research Articles

Chemometrics Analysis Combined with GC-MS and NMR Spectroscopy Analysis of Fatty Acids as a Means of Discriminating Butterfat Adulteration

The adulteration of butter has become a major problem in food industries. Butter has the similar characteristic to lard which makes lard a desirable adulterant in butter due to economic advantages. Therefore, the method of detection to analyse the adulteration practice must be developed. This study used NMR spectroscopy in combination with chemometrics for the authentication of butter from lard. The presence of lard as an adulterant in butter has been analysed using Gas Chromatography–Mass Spectrometry (GC-MS) and Nuclear Magnetic Resonance (NMR) spectroscopy with the aid of chemometric of Principal Component Analysis (PCA) and Discriminant Analysis (DA). PC1 described 82% of the variation while PC2 accounted for 15% of the variation resulted in a model that described 80% of the total variance in the data. With 82% of the peak variation along the first PC, it was clear that all seventeen samples of butter in the market and pure lard sample were formed according to their own group and showed two well-defined and well-separated group. DA model classified 100% of all samples accurately according to its group (butter and butter adulterated with animal fats), meaning that no samples were misclassified into the wrong group. Lard was successfully determined at 2.63 ppm. In this study, NMR and PCA analysis has successfully discriminated between the market sample and lard and the results established that there is no lard being adulterated in all commercial butter samples. This could be a potential identification approach to determine if the product has been deceived in market.

A novel divergent group of Ostreid herpesvirus 1 μVar variants associated with a mortality event in Pacific oyster spat in Normandy (France) in 2016.

The acute course of disease in young oysters infected by OsHV-1 and the rapid tissue degradation often preclude histological examination of specimens collected during outbreaks in field. Herein, live spat originated from two geographical areas were sampled just at the onset of a mortality event that occurred in Normandy (France) in June 2016. The lesions, associated with high OsHV-1 DNA quantities, were characterized by severe and diffuse haemocytosis mainly involving blast-like cells, myocyte degeneration and large, irregularly shaped degenerate eosinophilic cells in the connective tissue. The herpesvirus was identified by negative staining TEM and real-time PCR. Sequencing of the C region and ORFs 42/43 confirmed that the variants met the definition of OsHV-1 μVar. We sequenced 30 other ORFs in twenty OsHV-1-positive individuals and compared them to the μVar specimens isolated between 2009 and 2011. The ORFs encoding putative membrane proteins showed the highest number of variations. Seven different genotypes were identified, confirming the presence of relevant genetic diversity. Phylogenetic analysis provided evidence for a well-separated μVar new group, with an evolutionary divergence estimated at 0.0013 from the other μVar variants. The geographical distribution of these newly described variants and their effective virulence should be investigated in future.

Dust modeling of the combined ALMA and SPHERE datasets of HD 163296

Context. Multiwavelength observations are indispensable in studying disk geometry and dust evolution processes in protoplanetary disks. Aims. We aim to construct a three-dimensional model of HD 163296 that is capable of reproducing simultaneously new observations of the disk surface in scattered light with the SPHERE instrument and thermal emission continuum observations of the disk midplane with ALMA. We want to determine why the spectral energy distribution of HD 163296 is intermediary between the otherwise well-separated group I and group II Herbig stars. Methods. The disk was modeled using the Monte Carlo radiative transfer code MCMax3D. The radial dust surface density profile was modeled after the ALMA observations, while the polarized scattered light observations were used to constrain the inclination of the inner disk component and turbulence and grain growth in the outer disk. Results. While three rings are observed in the disk midplane in millimeter thermal emission at ~80, 124, and 200 AU, only the innermost of these is observed in polarized scattered light, indicating a lack of small dust grains on the surface of the outer disk. We provide two models that are capable of explaining this difference. The first model uses increased settling in the outer disk as a mechanism to bring the small dust grains on the surface of the disk closer to the midplane and into the shadow cast by the first ring. The second model uses depletion of the smallest dust grains in the outer disk as a mechanism for decreasing the optical depth at optical and near-infrared wavelengths. In the region outside the fragmentation-dominated regime, such depletion is expected from state-of-the-art dust evolution models. We studied the effect of creating an artificial inner cavity in our models, and conclude that HD 163296 might be a precursor to typical group I sources.

Morphological and molecular identification of potato and cereal cyst nematode isolates from Algeria and their phylogenetic relationships with other populations from distant theirgeographical areas

A nematode survey conducted in 2013 in Algeria, revealed that potato cyst nematodes (PCN) and cereal cyst nematodes (CCN) are widely distributed in several potato and cereal growing regions of the country. Sixteen PCN populations from five localities and five CCN populations from four of these localities were collected and characterized at the morphological and molecular levels. The PCN populations were identified as Globodera rostochiensis and G. pallida occurring separately or in mixed populations. Two species of CCN were detected. Heterodera avenae was found in four localities, whereas H. hordecalis only in one locality in association with H. avenae. The morphological and morphometric identification of PCN and CCN was confirmed by diagnostic ITS-RFLP profiles and sequencing. Phylogenetic analysis of the ITS, D2-D3 expansion domains of the 28S rRNA gene and 18S rRNA gene was made for PCN and CCN populations. Globodera pallida and G. rostochiensis from Algeria show great similarity with European and South American populations. Because of the high divergence among Algerian populations of G. pallida and G. rostochiensis it can be assumed that they were multi-introduced in Algeria. The most divergent population of G. pallida, that formed a well-separated group with some populations from Chile and Peru, suggests a later or independent introduction of this population into Algeria. Heterodera avenae and H. hordecalis formed a well-supported cluster with the corresponding populations.

Efficient IE-FFT and PO Hybrid Analysis of Antennas Around Electrically Large Platforms

An efficient hybrid analysis that combines integral equations (IE) with physical optics (PO) approximation is presented for antennas around an electrically large platform. In the analysis, the whole surface of the platform and antennas is divided into two regions, namely, the full-wave region and the PO region. In the full-wave region, the IE is modified by coupling into the PO contribution. Similar to the fast IE method, the modified impedance matrix is decomposed into the near-field couplings and the well-separated group couplings, respectively. By interpolating the Green's function, the couplings between two well-separated groups can be computed using fast Fourier transform (FFT). Due to the PO approximation, the hybrid method utilizes fewer unknowns and requires less solution time than the conventional IE-FFT.

Identification and Molecular Characterization of Subsubtype A4 in Central Africa

Phylogenetic analysis on partial env sequences of HIV-1-positive samples obtained from sentinel population groups in HIV serosurveillance studies in 1997 and 2002 in the Democratic Republic of Congo (DRC) revealed a high genetic diversity in the number of cocirculating subtypes/CRFs as well as intrasubtype diversity. A cluster of three strains that formed a distinct and well-separated group within the subtype A radiation was observed. To determine a more precise structure of these viruses, the full-length genomes were sequenced. Phylogenetic tree and bootscan analysis showed that all three newly characterized viruses formed a new nonrecombinant lineage that was more closely related to subtype A. The SUDI (Subtype Distance) program showed that the distances of the newly derived HIV-1 sequences to subtype A references fell in the range of distances previously characterized for subsubtypes. According to current nomenclature rules, we have thus designated this new lineage as subsubtype A4. Analysis of viral sequences from other African countries suggests that the A4 strains seem restricted to DRC where they already circulated at the onset of the HIV/AIDS epidemic.

A fast IE-FFT algorithm for solving PEC scattering problems

This paper presents a novel fast integral equation method, termed IE-FFT, for solving large electromagnetic scattering problems. Similar to other fast integral equation methods, the IE-FFT algorithm starts by partitioning the basis functions into multilevel clustering groups. Subsequently, the entire impedance matrix is decomposed into two parts: one for the self and/or near field couplings, and one for well-separated group couplings. The IE-FFT algorithm employs two discretizations one is for the unknown current on an unstructured triangular mesh, and the other is a uniform Cartesian grid for interpolating the Green's function. By interpolating the Green's function on a regular Cartesian grid, the couplings between two well-separated groups can be computed using the fast Fourier transform (FFT). Consequently, the IE-FFT algorithm does not require the knowledge of addition theorem. It simply utilizes the Toeplitz property of the coefficient matrix and is therefore applicable to both static and wave propagation problems.

Phylogeny of ants (Formicidae) based on morphology and DNA sequence data

In order to reconstruct ants' phylogeny, we analysed DNA sequences for two nuclear genes, abdominal-A and Ultrabithorax, from 49 species of ants and two outgroups. As these genes control the development of the first segments of the abdomen in insects, which are very variable in ants (petiole, postpetiole, and gaster constriction), we hypothesized that the morphological variations between the subfamilies may be correlated with mutations of some abd-A or Ubx regions. Contrarily to our hypothesis, these sequences are highly conserved. The differences observed concern mainly third codon positions and present some saturation. Phylogenetic reconstructions were carried out using the genetic raw sequence data and by combining them with a set of morphological data (Total Evidence). Relations among subfamilies of ants remains poorly resolved with molecular data only, but adding these data to morphological characters confirms and reinforce the topology of Baroni Urbani et al. (1992): a Poneroid complex [Ponerinae, Cerapachyinae, Leptanillinae and army ants], a Formicoid complex [Dolichoderinae, Formicinae] and a Myrmecoid complex [Myrmicinae, Myrmeciinae, Pseudomyrmecinae, Nothomyrmeciinae]. Our molecular results allow resolution near the branch tips and three subfamilies (Dolichoderinae, Formicinae and Pseudomyrmecinae) always appear as monophyletic. The Formicinae and the Dolichoderinae have close relationships. The Camponotini appear as a strong clade inside the Formicinae. The Ponerinae are separated in two parts: the Ectatommini and all other tribes. The Cerapachyinae, Dorylinae, and Ecitoninae belong to the same clade, the Cerapachyinae being confirmed in their subfamily status. The Myrmicinae appears to be very heterogeneous, with the Attini forming a very stable and well-separated group.

Genetic relationships between clinical isolates of Streptococcus pneumoniae, Streptococcus oralis, and Streptococcus mitis: characterization of "Atypical" pneumococci and organisms allied to S. mitis harboring S. pneumoniae virulence factor-encoding genes.

The oral streptococcal group (mitis phylogenetic group) currently consists of nine recognized species, although the group has been traditionally difficult to classify, with frequent changes in nomenclature over the years. The pneumococcus (Streptococcus pneumoniae), an important human pathogen, is traditionally distinguished from the most closely related oral streptococcal species Streptococcus mitis and Streptococcus oralis on the basis of three differentiating characteristics: optochin susceptibility, bile solubility, and agglutination with antipneumococcal polysaccharide capsule antibodies. However, there are many reports in the literature of pneumococci lacking one or more of these defining characteristics. Sometimes called "atypical" pneumococci, these isolates can be the source of considerable confusion in the clinical laboratory. Little is known to date about the genetic relationships of such organisms with classical S. pneumoniae isolates. Here we describe these relationships based on sequence analysis of housekeeping genes in comparison with previously characterized isolates of S. pneumoniae, S. mitis, and S. oralis. While most pneumococci were found to represent a closely related group these studies identified a subgroup of atypical pneumococcal isolates (bile insoluble and/or "acapsular") distinct from, though most closely related to, the "typical" pneumococcal isolates. However, a large proportion of isolates, found to be atypical on the basis of capsule reaction alone, did group with typical pneumococci, suggesting that they have either lost capsule production or represent as-yet-unrecognized capsular types. In contrast to typical S. pneumoniae, isolates phenotypically identified as S. mitis and S. oralis, which included isolates previously characterized in taxonomic studies, were genetically diverse. While most of the S. oralis isolates did fall into a well-separated group, S. mitis isolates did not cluster into a well-separated group. During the course of these studies we also identified a number of potentially important pathogenic isolates, which were frequently associated with respiratory disease, that phenotypically and genetically are most closely related to S. mitis but which harbor genes encoding the virulence determinants pneumolysin and autolysin classically associated with S. pneumoniae.

Diurnal blood pressure variations in normoalbuminuric type 1 diabetic patients

To test the hypothesis that normoalbuminuric type 1 diabetic patients segregate into groups with normal and elevated ambulatory blood pressure. To evaluate diurnal variation of blood pressure assessed by individual or fixed night-time periods. Cross-sectional study. Tertiary referral centre. Inclusion criteria for type 1 diabetic patients (n = 33): normal urinary albumin excretion (UAE age < 45 < 20 micrograms min-1), diabetes duration < or = 20 years, age 45 years. Healthy controls (n = 33) were matched for sex and age. Twenty-four hour, day-time, night-time and night/day ratio of ambulatory blood pressure. Twenty-four-hour blood pressure in diabetic patients did not differ significantly from a normal distribution. The 24-h systolic blood pressure was higher in diabetic patients than in healthy controls (difference: 6 mmHg, 95% confidence interval (CI) from 1 to 10 mmHg, P < 0.05), while no significant differences were found for diastolic values. The 24-h systolic blood pressure in diabetic patients with UAE above the median value (5.8 micrograms min-1) was higher than for those with lower UAE (difference: 7 mmHg, 95% CI from 0.5 to 13 mmHg, P < 0.05). The night/day ratio of diastolic blood pressure based on individual informations of the night period was (mean +/- SD) 80 +/- 6% in diabetic patients and 78 +/- 8% in controls (difference: 2%, 95% CI from -1 to 5%, not significant [NS]). This ratio increase significantly (P < 0.00001) to 90 +/- 5% in diabetes and to 84 +/- 7% in controls if a fixed night period from 22.30 hours to 06.30 hours was assumed. It was not possible to identify a well-separated group of normoalbuminuric type 1 diabetic patients with elevated ambulatory blood pressure. Values of UAE above the median in diabetic patients are associated with higher ambulatory blood pressure. Assessment of the night/day variation from fixed time-points should be abandoned because this leads to a serious underestimation of the nocturnal reduction in blood pressure.