Long range gene flow beyond predictions from oceanographic transport in a tropical marine foundation species

The transport of passively dispersed organisms across tropical margins remains poorly understood. Hypotheses of oceanographic transportation potential lack testing with large scale empirical data. To address this gap, we used the seagrass species, Halodule wrightii, which is unique in spanning the entire tropical Atlantic. We tested the hypothesis that genetic differentiation estimated across its large-scale biogeographic range can be predicted by simulated oceanographic transport. The alternative hypothesis posits that dispersal is independent of ocean currents, such as transport by grazers. We compared empirical genetic estimates and modelled predictions of dispersal along the distribution of H. wrightii. We genotyped eight microsatellite loci on 19 populations distributed across Atlantic Africa, Gulf of Mexico, Caribbean, Brazil and developed a biophysical model with high-resolution ocean currents. Genetic data revealed low gene flow and highest differentiation between (1) the Gulf of Mexico and two other regions: (2) Caribbean-Brazil and (3) Atlantic Africa. These two were more genetically similar despite separation by an ocean. The biophysical model indicated low or no probability of passive dispersal among populations and did not match the empirical genetic data. The results support the alternative hypothesis of a role for active dispersal vectors like grazers.

Effect of dental headlights spectrum on the polymerization and working time of light-cured resin composites

Background

The use of dental headlights is a common practice to better illuminate the operatory field and achieve excellence in restorative dentistry. However, visible light-cured dental materials can have reduced working time under headlight illumination. The aim of this study was to evaluate the influence of the spectral irradiance power of two dental headlights on the degree of polymerization and working time of light-curable dental composites.

Material and Methods

Two headlights, StarLight Nano 3 (StarMed) (SN) and Zeon Endevour XL (Orascoptic) (ZE) were characterized using a spectrophotometer coupled to an integrating sphere (MARC® Light Collector, BlueLight Analytics). The degree of conversion of the two composites, Filtek Supreme (3M) and Tetric Prime (Ivoclar Vivadent), was evaluated using an FTIR spectroscope (NicoletTM iS20, Thermo Fisher).

Results

Both headlights emitted a significant amount of blue light. The Zeon headlamp without filter emitted a broader spectrum with lower blue intensity and higher CRI than the White LED of the Nano 3. The Zeon headlamp with the blue blocking filter emitted a broader spectrum than the Orange LED of the Nano 3. There were no differences in the degree of conversion and working time of the Filtek Supreme and Tetric Prime composites when illuminated by the different headlamps. Both Zeon and the White LED of the Nano 3 were capable to cure the composites within only 5-10 minutes of irradiation. There were no changes in the degree of conversion of the composites when the Orange LED of the Nano 3 or the blue blocking filter of the Zeon were used.

Conclusions

Both headlights reduced the working time of light-cured materials. The use of orange filters prevented the composite polymerization and maintained the working time.

Key words:Surgical Headlight, degree of conversion, working time, light-curing.

Assessing the contribution of mangrove carbon and of other basal sources to intertidal flats adjacent to one of the largest West African mangrove forests

Mangrove forests are productive habitats and major potential exporters of organic matter and nutrients to adjacent habitats. Here we examine the extent to which mangrove carbon is transferred to adjacent intertidal food webs in the second largest mangrove-covered area in Africa, in Guinea-Bissau. Applying stable isotope analysis and mixing models, we made comparisons at two spatial scales: (1) a large scale, comparing intertidal flats with (mangrove sites) and without (control sites) adjacent mangrove forests regarding the carbon isotopic signature of macrozoobenthos and sediment organic matter (SOM), and the relative importance of potential primary food sources in sustaining macrozoobenthos, and (2) a fine scale, performing stable carbon isotope measurements along 200 m transects from the coastline out to open intertidal flats, to trace mangrove carbon in macrozoobenthos and in the SOM. We found no evidence that mangrove carbon sustains intertidal food webs, despite SOM being significantly more depleted in ¹³C in mangrove sites. Mangrove leaves had the lowest relative contribution to the diet of macrozoobenthos, while macroalgae, benthic microalgae and POM showed variable but overall relevant contributions. Yet, at a smaller scale, mangrove carbon was detectable in SOM and in most macrozoobenthos, being strongest within 50 m of the mangrove edge and quickly fading with increasing distance. Our results suggest that there is only a marginal input of mangrove carbon into the food webs of unvegetated intertidal flats. Still, this leaves open the possibility of mangrove forests acting as sources of dissolved inorganic carbon and processed nitrogen, which can be assimilated by the algae and subsequently fuel adjacent food webs.

A community-based transcriptomics classification and nomenclature of neocortical cell types

To understand the function of cortical circuits, it is necessary to catalog their cellular diversity. Past attempts to do so using anatomical, physiological or molecular features of cortical cells have not resulted in a unified taxonomy of neuronal or glial cell types, partly due to limited data. Single-cell transcriptomics is enabling, for the first time, systematic high-throughput measurements of cortical cells and generation of datasets that hold the promise of being complete, accurate and permanent. Statistical analyses of these data reveal clusters that often correspond to cell types previously defined by morphological or physiological criteria and that appear conserved across cortical areas and species. To capitalize on these new methods, we propose the adoption of a transcriptome-based taxonomy of cell types for mammalian neocortex. This classification should be hierarchical and use a standardized nomenclature. It should be based on a probabilistic definition of a cell type and incorporate data from different approaches, developmental stages and species. A community-based classification and data aggregation model, such as a knowledge graph, could provide a common foundation for the study of cortical circuits. This community-based classification, nomenclature and data aggregation could serve as an example for cell type atlases in other parts of the body.

[The role of mitral valve balloon valvuloplasty in the treatment of rheumatic mitral valve stenosis during pregnancy]

OBJECTIVE

To analyze the immediate results and the clinical evolution of a group of fertile age women with rheumatic mitral stenosis, in whom percutaneous balloon mitral valvuloplasty was performed before or during pregnancy.

PATIENTS AND METHOD

Eighty-one women with mitral stenosis, submitted to balloon mitral vavuloplasty, were studied. They were divided into three groups, according to their desire of no further pregnancies (group A; n = 19), pregnancy during the follow-up (group B; n = 23) or valvuloplasty was performed during pregnancy (group C; n = 39). Patients from group B and C were controlled during pregnancy, childbirth and puerperium, and the newborns of women in group C were followed from birth to the age of 5 years.

RESULTS

Mortality in the three groups was null and the incidence of miscarriage was 2 (8.6%) in group B and 3 (9.1%) in group C. Normal delivery was predominant in group B and delivery by caesarean was predominant in group B. Success was immediate in all the cases. The procedure was repeated in 3 women due to restenosis. The media valvar area rase from 0.93 to 2.05 cm2 in group A, from 1.28 to 2.04 cm2 in group B and from 0.84 to 2.14 cm2 in group C (intergroup p = NS). The functional class improved in the three groups of patients.

CONCLUSION

Percutaneous balloon mitral valvuloplasty is an effective, efficient method for the treatment of rheumatic mitral stenosis during pregnancy, after organogenesis, or at any time in a woman's life, as long as it is indicated according to clinical and echocardiographic evaluation criteria.

Diameter-reflux relationship in perforating veins of patients with varicose veins

PURPOSE

Treatment of chronic venous valvular insufficiency requires understanding of the hemodynamics of perforating veins. To preserve normal veins or veins that can function normally once primary sources of valvular insufficiency are removed, a better understanding of the diameter-reflux relationship is desirable. We measured reflux and diameters in 500 perforating veins of patients with varicose veins (C(2)E(P)A(SP)P(R)).

METHODS

Color flow duplex ultrasonography scanning was performed with the patient standing. Perforating veins were mapped medially in the thigh and medially, laterally, and posteriorly in the calf. Reflux was defined as reverse flow that lasted longer than 0.5 seconds. Diameters were measured on B-mode transverse projections at the crossing of the fascia. Competent versus incompetent vein diameters were compared by means of Student t test, one-way analysis of variance, and Bonferroni t test.

RESULTS

Diameters of competent and incompetent perforators averaged 2.5 +/- 0.9 mm (n = 17) and 4.7 +/- 1.9 mm (n = 17) at the medial thigh (P <.0002), 2.2 +/- 0.8 mm (n = 179) and 3.7 +/- 1.0 mm (n = 210) at the medial calf (P <.0001), 2.2 +/- 0.6 mm (n = 13) and 3.5 +/- 0.8 mm (n = 37) at the posterior calf (P <. 0001), and 2.1 +/- 0.8 mm (n = 9) and 3.3 +/- 0.7 mm (n = 18) at the lateral calf (P <.003), respectively. Perforating vein diameters of 3.5 mm or larger in the calf and thigh were associated with reflux in more than 90% of the cases.

CONCLUSION

An enlargement in the diameter of the perforating veins of 1 to 1.5 mm in the calf or 2 mm in the thigh of patients with varicose veins could be the difference between normal flow and reflux. Further studies are needed to confirm if elimination of reflux in patients with primary varicosity will transform incompetent perforators to competent ones.

Segmental atrial fibrillation resulting in chronic atrial dissociation. A case report

Atrial arrhythmias are diagnosed on the basis of the analysis of P wave morphology, timing and rate, the surface electrocardiogram, and intracardiac recordings. Recent intracardiac studies have demonstrated dissimilar atrial rhythms with direct intra-atrial recordings, the former otherwise not evident on the surface ECG (Zipes et al. 1972, Wu et al. 1975, Friedman et al. 1974, Gomes et al. 1981). This paper reports the electrocardiographic diagnosis of atrial dissociation made on the surface electrocardiogram. The findings suggest the following: (1) That sinus rhythm exists, with the dominant sinus rhythm depolarizing the major portion of the right as well as the left atrium; (2) Atrial fibrillation localized specifically to lead III, and at times to leads III and AVL, on the surface electrocardiogram; and (3) Intraesophageal recordings and echocardiography revealed an area of the posterior right and left atria that had wall motion abnormalities and electrical activity compatible with those of atrial fibrillation.