98 research outputs found
The influence of antero-posterior dentoskeletal pattern on the value of nasal soft tissue angles: a cephalometric study
Background: The aim of this study was to examine the influence of sagittal dentoskeletal pattern on the value of profile nasal soft tissue angles and estimate the significance of examined differences for each angle.Materials and methods: Lateral cephalograms were used to examine the nasofrontal angle, nasofacial angle, nasal tip angle, and nasolabial angle of 120 adult Caucasian subjects (60 male and 60 female) from the central Balkan area. Subjects were divided into four groups according to the ANB angle and incisors inclination: class I as the control group, class II division 1, class II division 2 and class III.Results: By evaluating the influence of sagittal dentoskeletal relationships on the values of examined angles, significant differences were found among subjects with class I and class II/2 (p = 0.028), so as class III (p = 0.002) for nasal tip angle. The nasofacial angle was found to differ among subjects with class I and class II/1 (p = 0.002), so as class III (p = 0.001).Conclusions: Different dentoskeletal patterns have significant influence on values of the nasal tip angle and nasofacial angle, and don’t have influence on the values of the nasofrontal and nasolabial angle
The influence of mandibular divergence on facial soft tissue thickness in class I patients: a cephalometric study
Background: The aims of this study were to evaluate the association between mandibular divergence and facial soft tissue thickness (FSTT) measured at different profile levels, and the gender difference in FSTT.Materials and methods: Lateral cephalograms were used to examine nine linear distances: the glabella area (G-G1), nasal (N-N1) and subnasal area (A-Sn), upper (Sd-Ls) and lower lip thickness (Id-Li), mentolabial sulcus (B-Sm), chin area (Pg-Pg1), gnathion area (Gn-Gn1) and menton area (Me-Me1) in 155 adult Caucasian subjects (79 males, 76 females) from the central Balkan area. Subjects were divided into three groups according to the ANB angle, Wit’s appraisal and SN/GoGn angle into normodivergent (28 male, 27 female subjects), hypodivergent (26 males, 25 females) and hyperdivergent (25 males, 24 females).Results: Progressive decreasing in the soft tissue thickness from hypo- towards hyperdivergent group was established in N-N1, A-Sn, Gn-Gn1, Me-Me1. There are significant differences in Gn-Gn1 and Me-Me1 (p < 0.02). Progressive increasing of FSTT happens only at the level of mentolabial sulcus and these differences are significant. Significant gender differences were established for the following distances: N-N1 in hyperdivergent, A-Sn in all three examined groups, the upper lip thickness in normo- and hyperdivergent, the lower lip thickness in hypodivergent, the thickness of mentolabial sulcus in hypo- and normodivergent, Pg-Pg1 in hyperdivergent and Me-Me1 in normodivergent subjects (p < 0.05).Conclusions: Facial soft tissue thickness showed a various degree of dependence on vertical developmental pattern at different levels of measurement. The areas whose thickness is significantly conditioned by this pattern were established: the chin area at level Gn-Gn1, Me-Me1 and the region of the mentolabial sulcus (B-Sm). At most levels, male subjects have thicker soft tissues and these differences are significant for all three groups in the subnasal area
Arginase Flavonoid Anti-Leishmanial in Silico Inhibitors Flagged against Anti-Targets
Arginase, a drug target for the treatment of leishmaniasis, is involved in the biosynthesis of polyamines. Flavonoids are interesting natural compounds found in many foods and some of them may inhibit this enzyme. The MetIDB database containing 5667 compounds was screened using an EIIP/AQVN filter and 3D QSAR to find the most promising candidate compounds. In addition, these top hits were screened in silico versus human arginase and an anti-target battery consisting of cytochromes P450 2a6, 2c9, 3a4, sulfotransferase, and the pregnane-X-receptor in order to flag their possible interactions with these proteins involved in the metabolism of substances. The resulting compounds may have promise to be further developed for the treatment of leishmaniasis
Epitaxial growth in dislocation-free strained alloy films: Morphological and compositional instabilities
The mechanisms of stability or instability in the strained alloy film growth
are of intense current interest to both theorists and experimentalists. We
consider dislocation-free, coherent, growing alloy films which could exhibit a
morphological instability without nucleation. We investigate such strained
films by developing a nonequilibrium, continuum model and by performing a
linear stability analysis. The couplings of film-substrate misfit strain,
compositional stress, deposition rate, and growth temperature determine the
stability of film morphology as well as the surface spinodal decomposition. We
consider some realistic factors of epitaxial growth, in particular the
composition dependence of elastic moduli and the coupling between top surface
and underlying bulk of the film. The interplay of these factors leads to new
stability results. In addition to the stability diagrams both above and below
the coherent spinodal temperature, we also calculate the kinetic critical
thickness for the onset of instability as well as its scaling behavior with
respect to misfit strain and deposition rate. We apply our results to some real
growth systems and discuss the implications related to some recent experimental
observations.Comment: 26 pages, 13 eps figure
Contrasting responses of above- and belowground diversity to multiple components of land-use intensity
Contamination, risk, and source apportionment of potentially toxic microelements in river sediments and soil after extreme flooding in the Kolubara River catchment in Western Serbia
Climate change is contributing to an increase in extreme weather events. This results in a higher river flooding risk, causing a series of environmental disturbances, including potential contamination of agricultural soil. In Serbia, the catastrophic floods of 2014 affected six river basins, including the Kolubara River Basin, as one of the larger sub-catchments of the large regional Sava River Basin, which is characterized by large areas under agricultural cultures, various geological substrates, and different types of industrial pollution. The main aim of this study was to establish the sources of potentially toxic elements in soil and flood sediments and the effect of the flood on their concentrations. Field sampling was performed immediately after water had receded from the flooded area in May 2014. In total, 36 soil samples and 28 flood sediment samples were collected. After acid digestion (HNO3), concentrations of the most frequent potentially toxic elements (PTE) in agricultural production (As, Cd, Cr, Cu, Ni, Pb, Zn) and Co which are closely related to the geological characteristics of river catchments, were analyzed. The origin, source, and interrelations of microelements, as well as BACKGROUND: values of the PTE of the river catchment, the pollution index (Pi), enrichment factor (Ef), and geological index (Igeo), were determined, using statistical methods such as Pearson correlations, principal component analysis (PCA), and multiple linear regression (MLRA). The content of the hot acid-extractable forms of the elements, PCA, and MLRA revealed a heavy geological influence on microelement content, especially on Ni, Cr, and Co, while an anthropogenic influence was observed for Cu, Zn, and Cd content. This mixed impact was primarily related to mines and their impact on As and Pb content. The pseudo-total concentrations of all the analyzed elements did not prove to be a danger in the catchment area, except for Cu in some samples, indicating point-source pollution, and Ni, whose pseudo-total content could be a limiting factor in agricultural production. For the Ef, the Ni content in 59% soil and 68% flood sediment samples is classified into influence classes. The similar pseudo-total contents of the elements studied in soil samples and flood sediment and their origin indicate that the long-term soil formation process is subject to periodic flooding in the Kolubara River Basin without any significant changes taking place. This implies that floods are not an endangering factor in terms of the contamination of soil by potentially toxic elements in the explored area
Evagination of Cells Controls Bio-Silica Formation and Maturation during Spicule Formation in Sponges
The enzymatic-silicatein mediated formation of the skeletal elements, the spicules of siliceous sponges starts intracellularly and is completed extracellularly. With Suberites domuncula we show that the axial growth of the spicules proceeds in three phases: (I) formation of an axial canal; (II) evagination of a cell process into the axial canal, and (III) assembly of the axial filament composed of silicatein. During these phases the core part of the spicule is synthesized. Silicatein and its substrate silicate are stored in silicasomes, found both inside and outside of the cellular extension within the axial canal, as well as all around the spicule. The membranes of the silicasomes are interspersed by pores of ≈2 nm that are likely associated with aquaporin channels which are implicated in the hardening of the initial bio-silica products formed by silicatein. We can summarize the sequence of events that govern spicule formation as follows: differential genetic readout (of silicatein) → fractal association of the silicateins → evagination of cells by hydro-mechanical forces into the axial canal → and finally processive bio-silica polycondensation around the axial canal. We termed this process, occurring sequentially or in parallel, bio-inorganic self-organization
Crop pests and predators exhibit inconsistent responses to surrounding landscape composition
The idea that noncrop habitat enhances pest control and represents a win–win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win–win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies
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Spatiotemporal climate and vegetation greenness changes and their nexus for Dhidhessa River Basin, Ethiopia
Background
Understanding spatiotemporal climate and vegetation changes and their nexus is key for designing climate change adaptation strategies at a local scale. However, such a study is lacking in many basins of Ethiopia. The objectives of this study were (i) to analyze temperature, rainfall and vegetation greenness trends and (ii) determine the spatial relationship of climate variables and vegetation greenness, characterized using Normalized Difference in Vegetation Index (NDVI), for the Dhidhessa River Basin (DRB). Quality checked high spatial resolution satellite datasets were used for the study. Mann–Kendall test and Sen’s slope method were used for the trend analysis. The spatial relationship between climate change and NDVI was analyzed using geographically weighted regression (GWR) technique.
Results
According to the study, past and future climate trend analysis generally showed wetting and warming for the DRB where the degree of trends varies for the different time and spatial scales. A seasonal shift in rainfall was also observed for the basin. These findings informed that there will be a negative impact on rain-fed agriculture and water availability in the basin. Besides, NDVI trends analysis generally showed greening for most climatic zones for the annual and main rainy season timescales. However, no NDVI trends were observed in all timescales for cool sub-humid, tepid humid and warm humid climatic zones. The increasing NDVI trends could be attributed to agroforestry practices but do not necessarily indicate improved forest coverage for the basin. The change in NDVI was positively correlated to rainfall (r2 = 0.62) and negatively correlated to the minimum (r2 = 0.58) and maximum (r2 = 0.45) temperature. The study revealed a strong interaction between the climate variables and vegetation greenness for the basin that further influences the biophysical processes of the land surface like the hydrologic responses of a basin.
Conclusion
The study concluded that the trend in climate and vegetation greenness varies spatiotemporally for the DRB. Besides, the climate change and its strong relationship with vegetation greenness observed in this study will further affect the biophysical and environmental processes in the study area; mostly negatively on agricultural and water resource sectors. Thus, this study provides helpful information to device climate change adaptation strategies at a local scale
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