RESUMEN

The propagation of oil palm through somatic embryogenesis is the most effective method of cloning this palm tree; however, in vitro cultivation can lead to abnormalities in plant tissue, such as hyperhydricity. The present study aimed to evaluate the difference in anatomical, morphological, and histochemical characteristics, and gene expression in normal (Nm) and hyperhydric (Hh) somatic embryos of oil palm. For this purpose, Nm and Hh somatic embryos were collected from the differentiation medium and were submitted to anatomical and histochemical analyses to assess the nucleus/cytoplasm ratio (toluidine blue), starch (Lugol), and proteins (XP), as well as ultrastructural analyses via transmission electron microscopy. Additionally, gene expression analyses were performed to gain a better understanding on the molecular aspect of hyperhydric abnormality. A higher quantity of differentiated Nm somatic embryos per explant was observed, with a germination rate close to zero in Hh somatic embryos. Additionally, a higher accumulation of proteins and starch was found in Nm somatic embryos when compared to Hh embryos. It was also noted that in Nm somatic embryos, protein reserves were primarily located in the proximal region (embryonic axis), whereas starch reserves were mainly accumulated in the distal region of the somatic embryos. Hh somatic embryos exhibit insignificant starch reserves, and a greater number of intercellular spaces were observed compared to Nm somatic embryos. However, some Hh somatic embryos displayed histochemical characteristics similar to Nm, which could explain the occurrence of reversions from the Hh state to the Nm state observed in this study. Regarding molecular analyses, the gene expression results obtained showed that out of the 19 genes analyzed, 17 were upregulated in hyperhydric embryos when compared to the control condition (normal somatic embryos). Genes involved in stress response, energy metabolism, defense, membrane transport, hormonal regulation, and development were positively regulated, especially those involved in ethylene synthesis and energetic metabolism. To the best of our knowledge, this is the first in-depth study addressing hyperhydricity in oil palm during somatic embryogenesis.

RESUMEN

The success of in vitro cultivation, particularly for micropropagation purposes, depends on the efficient control of contaminants. In this context, the sterilization of plant material constitutes a fundamental step in initiating cultures. Microbial contaminants can be found either on the surface (epiphyte) or inside plant explants (endophyte). However, the latter is generally challenging to detect and may not always be eradicated through surface sterilization alone. Endophyte contaminants, such as bacteria, can persist within plant material over several cultivation cycles, potentially interfering with or inhibiting in vitro establishment, growth, or recovery of cryopreserved materials. Therefore, microscopy techniques, such as electron microscopy, can yield valuable insights into bacterial endophytes' localization, tissue colonization patterns, and functions in in vitro plant culture. This information is essential for adopting effective strategies for eliminating, preventing, or harmonious coexistence with contaminants.

Asunto(s)

RESUMEN

This chapter describes a step-by-step protocol for rapid serological quantification of global DNA methylation by enzyme-linked immunosorbent assay (ELISA) in plant tissue culture specimens. As a case study model, we used the coconut palm (Cocos nucifera), from which plumules were subjected to somatic embryogenesis followed by embryogenic calli multiplication. DNA methylation is one of the most common epigenetic markers in the regulation of gene expression. DNA methylation is generally associated with non-expressed genes, that is, gene silencing under certain conditions, and the degree of DNA methylation can be used as a marker of various physiological processes, both in plants and in animal cells. Methylation consists of adding a methyl radical to carbon 5 of the DNA cytosine base. Herein, the global DNA methylation was quantified by ELISA with antibodies against methylated cytosines using a commercial kit (Zymo-Research™). The method allowed the detection of methylation in total DNA extracts from coconut palm embryogenic calli (arising from somatic embryogenesis) cultivated in liquid or solid media by using antibodies against methylated cytosines and enzymatic development with a colorimetric substrate. Control samples of commercially provided Escherichia coli bacterial DNA with previously known methylation percentages were included in the ELISA test to construct an experimental methylation standard curve. The logarithmic regression of this E. coli standard curve allowed methylation quantification in coconut palm samples. The present ELISA methodology, applied to coconut palm tissue culture specimens, is promising for use in other plant species and botanical families. This chapter is presented in a suitable format for use as a step-by-step laboratory procedure manual, with theoretical introduction information, which makes it easy to apply the protocol in samples of any biological nature to evaluate DNA global methylation associated with any physiological process.

Asunto(s)

RESUMEN

OBJECTIVES: To investigate long-term alveolar ridge bone changes in patients treated with the split-crest technique (SCT) with simultaneous implant placement. MATERIALS AND METHODS: Alveolar ridge width (ARW) was measured with a caliper immediately before (ARW1) and after SCT (ARW2) with a caliper. Existing CBCT scans taken at least 5 years postoperatively were used to assess the healed ARW (ARWF), buccal bone thickness (BBT), and lingual/palatal bone thickness (L/PBT) at 0, 3, and 5 mm apically from implant platform level (IPL). The distance between IPL and buccal bone crest (IPL-BBC) was also measured. Findings were compared with Wilcoxon and Student's t tests (p < .05). RESULTS: Records of thirty patients with 85 implants were included. Eleven patients (31 implants) presented CBCT scans taken in two separate occasions, resulting in 116 measurements. Tomographic follow-up ranged from 5 to 18 years (11.5 ± 4.18 years). Mean ARW increased from 3.2 ± 0.6 to 6.6 ± 0.48 mm after SCT, but significantly reduced overtime to 4.46 ± 0.83 mm (ARWF) (p < .0001). Mean BBT was 0.5 ± 0.9, 1.3 ± 0.9, and 2.0 ± 1.2 mm, while mean L/PBT was 0.9 ± 0.7, 1.6 ± 0.9, and 2.1 ± 1.0 mm at 0, 3, and 5 mm from IPL, respectively. IPL-BBC distance varied up to 8.7 mm (1.4 ± 2.0 mm), with 56/116 measurements (51/85 implants) showing IPL-BBC = 0 mm. CONCLUSION: Although SCT with simultaneous implant placement can predictably increase ARW postoperatively, ARW tended to significantly reduce over time, due to reductions in BBT and L/PBT, especially coronally. Nonetheless, 60% of the implants still presented some buccal bone at IPL.

RESUMEN

Aim: To evaluate real-world data on treatment patterns in Argentina and Brazil in patients with ovarian cancer.Methods: This study evaluated de-identified antineoplastic exposure data from a private healthcare provider in Argentina and health claims database (Orizon) in Brazil from 2010 to 2019 and 2015 to 2020, respectively.Results: Platinum-based chemotherapy was the most common first-line therapy (Argentina: n =311 [87.6%]; Brazil: n = 1142 [79.3%]). The proportion of patients receiving platinum-based chemotherapy declined across both populations from first- to second-line, while use of non-platinum-based, targeted, and hormone therapies increased. Duration of platinum-based treatment and time to next treatment decreased from first- to fourth-line.Conclusion: There is an unmet need for effective therapies that can prolong time to next treatment in ovarian cancer in Argentina and Brazil.

[Box: see text].

Asunto(s)

RESUMEN

Sperm competition and male mating rate are two non-mutually exclusive key evolutionary pressures selecting for larger testes within and across animal taxa. A few studies have tried to test the role of mating rate in the absence of sperm competition. Under the mating rate hypothesis, particular phenotypes of a given population that are expected to gain more mates (e.g., more ornamented males) are expected to make higher investments in testes size (a proxy for sperm production). We test this prediction in Polistes simillimus, a neotropical paper wasp in which females are single mated (no sperm competition) and males can mate with multiple partners. Testes size was predicted by body size (positive association), sexual ornamentation (negative association), and their interaction (among small males, testes size was positively related to ornamentation, but the opposite pattern was observed among large males). We propose that small-bodied well-ornamented males may face the highest risk of sperm depletion. Small-bodied males make relatively higher investment in testes size when highly ornamented. This strategy might be less profitable to large males, as they have overall larger testes. Our results provide strong evidence for the mating rate hypothesis.

Asunto(s)

RESUMEN

AIMS: Although elasmobranchs are consumed worldwide, bacteriological assessments for this group are still sorely lacking. In this context, this study assessed bacteria of sharks and rays from one of the most important landing ports along the Rio de Janeiro coast. METHODS AND RESULTS: Bacteria were isolated from the cloacal swabs of the sampled elasmobranchs. They were cultured, and Vibrio, Aeromonas, and Enterobacterales were isolated and identified. The isolated bacteria were then biochemically identified and antimicrobial susceptibility assays were performed. Antigenic characterizations were performed for Salmonella spp. and Polymerase Chain Reaction (PCR) assays were performed to identify Escherichia coli pathotypes. Several bacteria of interest in the One Health context were detected. The most prevalent Enterobacterales were Morganella morganii and Citrobacter freundii, while Vibrio harveyi and Vibrio fluvialis were the most prevalent among Vibrio spp. and Aeromonas allosacharophila and Aeromonas veronii bv. veronii were the most frequent among Aeromonas spp. Several bacteria also displayed antimicrobial resistance, indicative of Public Health concerns. A total of 10% of Vibrio strains were resistant to trimethoprim-sulfamethoxazole and 40% displayed intermediate resistance to cefoxitin. Salmonella enterica strains displayed intermediate resistance to ciprofloxacin, nalidixic acid and streptomycin. All V. cholerae strains were identified as non-O1/non-O139. The detected E. coli strains did not exhibit pathogenicity genes. This is the first study to perform serology assessments for S. enterica subsp. enterica isolated from elasmobranchs, identifying the zoonotic Typhimurium serovar. Salmonella serology evaluations are, therefore, paramount to identify the importance of elasmobranchs in the epidemiological salmonellosis chain. CONCLUSIONS: The detection of several pathogenic and antibiotic-resistant bacteria may pose significant Public Health risks in Brazil, due to high elasmobranch consumption rates, indicating the urgent need for further bacteriological assessments in this group.

Asunto(s)

RESUMEN

The osseodensification (OD) technique differs from conventional milling for dental implant installation in that it preserves the prepared bone and compacts it toward the apex and lateral walls of the socket, resulting in bone compaction. By enabling autografting, bone expansion, and high implant insertion torques, OD has become an increasingly popular option. The aim of this clinical case report is to demonstrate the predictability of combining OD with guided bone and tissue regeneration (GBR/GTR) techniques for bone expansion in the maxilla with reduced thickness, while avoiding other reconstructive surgeries. The report presents the treatment of a 32-year-old female patient who had cosmetic concerns regarding the anterior maxillary region. The patient was using an adhesive prosthesis with pontic on tooth 13 fixed between teeth 12 and 14. After the case was planned, it was decided that bone expansion in the region would be performed using the OD technique. The implant installation (AR Torque, 3.5 × 11.5 mm, Conexão®) and guided bone regeneration (GBR) were done with the assistance of L-PRF (Stick Bone, associated with L-PRF membrane). Following the osseointegration period, a provisional resin crown was fabricated, and a collagen matrix membrane (Mucoderm®) was used to increase vestibular soft tissue volume and shape the patient's gingival profile. After a period of 120 days, the final crown was created and observed for a span of 5 years. The results showed stability of the case along with maintaining its esthetic and satisfactory function. The use of the osseodensification technique coupled with a connective tissue graft substitute has been anticipated for a long time. It has proven to be an excellent alternative to autogenous grafts.

RESUMEN

Fungus-based biopesticides have been used worldwide for crop pest control as a safer alternative to chemical pesticides such as neonicotinoids. Both agrochemicals can be lethal and may also trigger side effects on the behavioral traits of non-target social insects, which play a crucial role in providing essential biological pest control services in agroecosystems. Here, we evaluated whether a commercial formulation of the entomopathogenic fungus Beauveria bassiana or the neonicotinoid imidacloprid causes mortality in foragers of Mischocyttarus metathoracicus. These social wasps are natural enemies of caterpillars and other herbivorous insects and inhabit both urban and agricultural environments in Brazil. We also tested whether wasps discriminate between biopesticide-exposed and unexposed conspecifics. Through a combination of laboratory (survival assay) and field experiments (lure presentation), along with chemical analyses (cuticular hydrocarbon profiles), we showed that topic exposure to the label rate of each pesticide causes a lethal effect, with the biopesticide exhibiting a slower effect. Moreover, wasps do not discriminate biopesticide-exposed from unexposed conspecifics, likely because of the similarity of their cuticular chemical profiles 24 h after exposure. Overall, the delayed lethal time at the individual level, combined with the indistinctive chemical cues of exposure and the lack of discrimination by conspecifics suggests that the fungal biopesticide may ultimately pose a threat to the colony survival of this predatory wasp.

Asunto(s)

RESUMEN

Currently, the use of algorithms and computer vision systems for metrological purposes has increased in different areas of knowledge to reduce human error and process deviations, consequently increasing reliability and reducing measurement uncertainties. This study presents a model for estimating the uncertainty of Feret's diameter (DF ) measurements of scanning electron microscopy (SEM) images from regular and irregular gunshot residue (GSR) particles at different magnifications. The data were extracted using the automatic measurement algorithm developed by the Brazilian Institute of Metrology, Quality and Technology (Inmetro). The proposed uncertainty model was based on the recommendations of the guide to the expression of uncertainty in measurement (GUM). The gold standard technique to identify and detect GSR particles is the SEM coupled to energy dispersive X-ray spectroscopy (SEM/EDS), which was used in the study. The low uncertainty values obtained in this study are justified by the refinement of the measurements performed at each stage of digital image procedures. The proposed uncertainty model contributes in an innovative way to the metrological evaluation of regular and irregular GSR particles at different images magnifications. The correct morphometry definition of these particles allows to study their distinction from other possible sources of GSR and, above all, their correlation with the type of ammunition used when firing the firearm. These measurement uncertainty calculations can be applied to any object images acquired by SEM, which provides more confidence in the results of measurements of the object of interest.

RESUMEN

The recent geographic spread of Leishmania infantum along the borders of Argentina, Brazil and Paraguay has been highlighted. In our previous study, Lutzomyia longipalpis was found in 55 of 123 patches surveyed, and in some patches, sandflies were found at higher densities, forming hotspots. Based on the One Health approach, we investigated the seasonality of the vector, the presence of parasite DNA, and the environmental factors that contribute to vector and parasite dispersal in these previously described hotspots in Foz do Iguaçu, Brazil. Entomological surveys were conducted monthly for one year. Fourteen hotspots peridomicile and six intradomicile were sampled. PCR was used to assess the prevalence of Leishmania DNA in sandflies. Zero-inflated negative binomial regression was used to determine the association of micro- and mesoscale environmental variables with the occurrence and abundance of the three most abundant sandfly species sampled. A total of 3543 species were captured, with Lutzomyia longipalpis being the predominant species (71.78%) of the 13 species found. Evandromyia edwardsi, Expapillata firmatoi, Micropygomyia ferreirana and Pintomyia christenseni were reported for the first time in the region. NDVI, distance to water, precipitation, west-to-east wind, wind speed, maximum and minimum relative humidity, and sex were significant variables associated with vector presence/abundance in the environment. Vector presence/abundance in the peridomicile was associated with precipitation, altitude, maximum temperature, minimum and maximum relative humidity, west-to-east wind, wind speed, and sex. Leishmania DNA was detected in an average of 21% of Lu. longipalpis throughout the year. Vector abundance is concentrated in urban and peri-urban areas, with some specimens present in different parts of the city and some sites with high vector abundance. This distribution suggests that the risk of actual contact between humans and parasite vectors in urban areas during the epidemic period is associated with patches of peri-urban vegetation and then extends into urban areas.

RESUMEN

During social interactions, the behavior of an individual often depends on the sex of its social partner. Many animal societies have males and females that play very different behavioral roles, although they coexist and interact non-sexually. At specific phases of the colony cycle, social wasp females and males are contemporaries within a nest, they often interact, although mating occurs mostly off the nest, therefore providing an opportunity to test sex discrimination in contexts other than classical sexual ones. We performed a lure presentation experiment to test if Mischocyttarus metathoracicus discriminate between conspecifics of the 2 sexes during on-nest social interactions. Female wasps discriminated conspecific sex during experimentally simulated nest intrusions. Visual and chemical cues may account for this sex discrimination. Despite sex discrimination (evidenced by differential inspective behavior from the nest females toward the female and the male lures), female wasps were as aggressive toward lures of both sexes. In the female-dominated hymenopteran societies, males are often subordinate and not aggressive on nest, resulting in females directing less aggression to them compared to other females. Instead, M. metathoracicus males and females are both aggressive toward nestmates, so they might be perceived as similar threat during on-nest social interactions.

RESUMEN

Microplastics (MPs) are widespread pollutants of emerging concern, and the risks associated with their ingestion have been reported in many organisms. Terrestrial environments can be contaminated with MPs, and terrestrial organisms, including arthropods, are predisposed to the risk of ingesting MPs. In the current study, the larvae of the paper wasp Polistes satan were fed two different doses (6 mg or 16 mg at once) of polystyrene MPs (1.43 mm maximum length), and the effects of these treatments on immature development and survival till adult emergence were studied. Ingestion of the two doses resulted in mortality due to impaired defecation prior to pupation. The survival of larvae that ingested 16 mg of MPs was significantly lower than that of the control. The ingestion of 16 mg of MPs also reduced the adult emergence (11.4%) in comparison to the control (44.4%). MPs were not transferred from the larvae to the adults that survived. These findings demonstrate that MP ingestion can be detrimental to P. satan, e.g. larval mortality can decrease colony productivity and thus the worker force, and that MPs can potentially affect natural enemies that occur in crops, such as predatory social wasps.

Asunto(s)

RESUMEN

PURPOSE: The incidence of hip fractures is increasing exponentially due to an aging Brazilian population. Older people had significant comorbidities which increases the risk of post-operative mortality. Our purpose was to examine the association between pre-operative infections and comorbidities on the risk of post-operative in-hospital mortality after proximal femur fracture surgery's, beyond that, to evaluate the association between comorbidities and time to surgery. METHODS: This is a population-based cohort retrospective study, using medical records of all six year consecutive surgical procedures for correction of hip fracture in a tertiary teaching Hospital in Brazil. The exclusion criteria aimed to exclusively allocate patients who had their first hip fracture secondary to low-energy trauma. Multivariate logistical regression was performed and receiver operating characteristic (ROC) curve with area under curve (AUC) to evaluate the sensitivity and specificity of the model. p-value < 0.05 was considered significant. RESULTS: Final sample was composed by 856 consecutive patients with 81 years of median and 164 patients were excluded. The median length of hospital say was five days with - l mortality at 3.6%. Significant variables for increased mortality included the presence of pre-operative infection (odds ratio (OR): 3.9(1.12-8.54), chronic obstructive pulmonary disease (COPD) (OR: 3.83(1.36-10.82)), and systemic arterial hypertension (SAH) (OR: 4.1(1.18-14.25)). Development of pre-operative infection was associated with a delay to surgery (OR: 1.1 (1.08-1.13)). CONCLUSIONS: In older people with proximal femur fracture, the presence of pre-operative infection, COPD and SAH were the strongest risk factor for post-operative in-hospital mortality. Pre-operative infection was associated with statistically significant delay to surgery.

Asunto(s)

RESUMEN

Objective: To evaluate the association between attitudes, health behaviors, and the use of tobacco and alcohol among nursing students. Materials and method: Exploratory, descriptive and cross-sectional study conducted with 182 undergraduate nursing students in the countryside of São Paulo, Brazil. Sociodemographic Information Form, Alcohol Use Disorders Identification Test ­ C (AUDIT-C), Fagerström Test for Nicotine Dependence (FTND), Attitudes and Health Behaviors Questionnaire (AHBQ), and Patient Health Questionnaire ­ 2 (PHQ-2) were applied. Results: More than half of the students showed appropriate health behaviors and positive attitudes. Approximately 50% of the participants had consumed alcoholic beverages in the last month. Experimental use of illicit drugs and smoking were also observed. In addition, students who reported excessive alcohol use presented a deficit in self-care. Conclusions: The precariousness in health attitudes and behaviors identified in this study was associated with various patterns of psychoactive substance use. Thus, the results indicate the need for interventions aimed at promoting well-being and a healthy lifestyle in the university environment.

Objetivo: evaluar la asociación entre las actitudes, los comportamientos de salud y el uso de tabaco y alcohol entre un grupo de estudiantes de enfermería. Materiales y método: estudio exploratorio, descriptivo y transversal realizado con 182 estudiantes de pregrado en enfermería en São Paulo, Brasil. Se aplicaron los siguientes instrumentos: Formulario de Información Sociodemográfica, Prueba de Identificación de Trastornos Derivados del Consumo de Alcohol ­ C (AUDIT-C), Test de Fagerström para Adicción a la Nicotina (FTND), Cuestionario sobre Actitudes y Conductas de Salud (CACS) y Cuestionario de Salud del Paciente ­ 2 (PHQ-2). Resultados: más de la mitad de los estudiantes mostraron comportamientos de salud apropiados y actitudes positivas. Aproximadamente 50 % de los participantes había consumido bebidas alcohólicas en el último mes. También se observó el uso experimental de drogas ilícitas y tabaco. Además, los estudiantes que reportaron el consumo excesivo de alcohol presentaron un déficit en el autocuidado. Conclusiones: la precariedad en las actitudes y los comportamientos de salud identificados en este estudio fue asociada con diversos patrones de uso de sustancias psicoactivas. Los resultados señalan la necesidad de intervenciones destinadas a promover el bienestar y un estilo de vida saludable en el ámbito universitario.

Objetivo: avaliar a associação entre as atitudes, os comportamentos de saúde e o uso de tabaco e álcool num grupo de estudantes de enfermagen. Materiais e método: estudo exploratório, descritivo e transversal realizado com 182 estudantes de graduação em enfermagem em São Paulo, Brasil. Foram aplicados os seguintes instrumentos: Formulário de Informação Sociodemográfica, Teste de Identificação de Transtornos Derivados do Consumo de Álcool-C (AUDIT-C), Teste de Fagerström para a Dependência de Nicotina (FTND), Questionário sobre Atitudes e Condutas de Saúde (CACS) e Questionário de Saúde do Paciente-2 (PHQ-2). Resultados: mais da metade dos estudantes mostraram comportamentos de saúde apropriados e atitudes positivas. Aproximadamente 50 % dos participantes tinham consumido bebidas alcoólicas no último mês. Também foi observado o uso experimental de drogas ilícitas e tabaco. Além disso, os estudantes que relataram o consumo excessivo de álcool apresentaram um déficit no autocuidado. Conclusões: a precariedade nas atitudes e comportamentos de saúde identificados neste estudo foi associada com diversos padrões de uso de substâncias psicoativas. Os resultados indicam a necessidade de intervenções destinadas a promover o bem-estar e um estilo de vida saudável no contexto universitário.

Asunto(s)

RESUMEN

Introduction Orthognathic surgeries require the use of surgical splints (SS) to stabilize the occlusion and the segments fixed with plates and screws. Technological advances in the field of computing and the possibility of generating three-dimensional (3D) images have brought different possibilities for making SS, which has generated greater predictability and customization of surgical plans. The bibliometric study can have a qualitative character through the scope of articles in a certain area of knowledge. It is a selection process that can track a topic or scientific production. Methods The present study aimed to carry out a bibliometric literature review, in order to assess the evolution of the use of SS and the different planning protocols in orthognathic surgery. The Scopus database was used, with the terms "splint" and "orthognathic surgery." Results A total of 331 articles were found. These were exported to Rayyan for application of the inclusion and exclusion criteria and selection of articles. A total of 76 references were selected and exported to the VOSviewer application for the analysis of bibliometric data. Conclusions Orthognathic surgery was initially not associated with any computerized technological resource; however, it underwent updates between the years 2010 to 2012. These advances allowed surgical planning to become faster, cheaper, and more accurate.

RESUMEN

This article introduced a digital workflow by using data merging and a computer-aided design and computer-aided manufacturing (CAD-CAM) milled surgical guide for an esthetic crown lengthening procedure. The superimposition of intraoral scanning, digital photographs, cone beam computed tomography, and a CAD-CAM surgical guide should increase the predictability of esthetic crown lengthening surgery.

Asunto(s)

RESUMEN

Risk assessments of agrochemicals on non-target insects are biased in studies with surrogate groups, such as pollinators. In social insects, such investigations are generally restricted to lethal tests with adults maintained individually, simulating a non-realistic scenario. Here, we performed a holistic approach to resemble a chronic field exposure of Polistes versicolor (Hymenoptera: Vespidae) to a common biopesticide. These wasps are predators that perform biological control in the agroecosystems. Wasps were chronically subjected to the ingestion of different concentrations of azadirachtin. The neonicotinoid imidacloprid was used as a positive control. For the first time, we demonstrated that the biopesticide azadirachtin is detrimental for individual and colony survival and impairs colony reproduction of a social wasp maintained in the laboratory. Our data also indicated that neonicotinoid imidacloprid is harmful to wasps and their colonies. Therefore, the concomitant use of azadirachtin and paper wasps in integrated pest management strategies should be carefully evaluated, because the constant use of this pesticide can be detrimental for social wasps, possibly reducing biological control.

Asunto(s)

RESUMEN

Biological nitrogen fixation is a key process for the maintenance of natural ecosystems productivity. In tropical forests, the contribution of asymbiotic nitrogen fixation (ANF) to the nitrogen (N) input has been underestimated, even though few studies have shown that ANF may be as important as symbiotic nitrogen fixation in such environments. The inputs and abiotic modulators of ANF in the Amazon forest are not completely understood. Here, we determined ANF rates and estimated the N inputs from ANF in the phyllosphere, litter and rhizospheric soil of nine tree species in the Amazon forest over time, including an extreme drought period induced by the El Niño-Southern Oscillation. Our data showed that ANF rates in the phyllosphere were 2.8- and 17.6-fold higher than in the litter and rhizospheric soil, respectively, and was highly dependent on tree taxon. Sampling time was the major factor modulating ANF in all forest compartments. At the driest period, ANF rates were approximately 1.8-fold and 13.1-fold higher than at periods with higher rainfall, before and after the extreme drought period, respectively. Tree species was a key modulator of ANF in the phyllosphere, as well as N and Vanadium concentrations. Carbon, molybdenum and vanadium concentrations were significant modulators of ANF in the litter. Based on ANF rates at the three sampling times, we estimated that the N input in the Amazon forest through ANF in the phyllosphere, litter and rhizospheric soil, was between 0.459 and 0.714 kg N ha-1 yr-1. Our results highlight the importance of ANF in the phyllosphere for the N input in the Amazon forest, and suggest that changes in the patterns of ANF driven by large scale climatic events may impact total N inputs and likely alter forest productivity.

Asunto(s)

RESUMEN

INTRODUCTION: The infringement of supracrestal tissue attachment by subgingival restorative margins, extensive caries, and root fractures, can compromise the periodontal health, resulting in inflammation and loss of periodontal supporting tissues. This report describes a case of a root fracture on the upper left central incisor that was successfully treated using a conservative approach, by applying the restorative alveolar interface (RAI) management combined with tunnel technique and a subepithelial connective tissue graft (SCTG). CASE PRESENTATION: A 24-year-old male patient presented with a provisional single-unit fixed prosthesis on his upper left central incisor, in function for 4 years, with the chief complaint of prosthesis discoloration. After clinical and radiographic examination, a diagnosis of root fracture was established. Following the removal of the provisional prosthesis, a full-thickness flap was elevated creating a tunnel. The elimination of the fracture line/angle, root recontouring, and planning was then performed with the aid of a conical long diamond bur and periodontal curets. Additionally, an SCTG was placed buccally into the tunnel. The final zirconia layered with E-max crown was placed 6 months after surgery. At 12- and 24-month follow-up, the periodontal tissues presented healthy aspect, no bleeding on probing, and a 4-mm probing depth. CONCLUSIONS: Surgical repositioning of the restorative margin can be an alternative and conservative treatment approach to compromised teeth with subgingival fracture line/angle. However, case selection should be carefully considered and restorability assessed as limitations might apply.

Asunto(s)