Decoding Non-coding Variants: Recent Approaches to Studying Their Role in Gene Regulation and Human Diseases.

Genome-wide association studies (GWAS) have mapped over 90% of disease- and quantitative-trait-associated variants within the non-coding genome. Non-coding regulatory DNA (e.g., promoters and enhancers) and RNA (e.g., 5' and 3' UTRs and splice sites) are essential in regulating temporal and tissue-specific gene expressions. Non-coding variants can potentially impact the phenotype of an organism by altering the molecular recognition of the cis-regulatory elements, leading to gene dysregulation. However, determining causality between non-coding variants, gene regulation, and human disease has remained challenging. Experimental and computational methods have been developed to understand the molecular mechanism involved in non-coding variant interference at the transcriptional and post-transcriptional levels. This review discusses recent approaches to evaluating disease-associated single-nucleotide variants (SNVs) and determines their impact on transcription factor (TF) binding, gene expression, chromatin conformation, post-transcriptional regulation, and translation.

Chromoproduct approach to achieve environmentally sound management of e-waste plastics: Colombian project case.

Research to prevent releases of brominated flame retardants listed as persistent organic pollutants by the Stockholm Convention (POP-BFRs) was conducted through an international cooperation project in Colombia. Six waste electrical and electronic equipment (WEEE) management facilities implemented: 1) sorting e-waste by product type and color (black, white, and other; henceforth called chromoproducts), 2) sampling test products and their plastic fraction (called sets, separated by polymer type), 3) monitoring mass, bromine and antimony contents by hand-held X-ray fluorescence (XRF) and POP-BFRs such as polybrominated diphenyl ethers (PBDEs) by gas chromatography and mass spectrometry (GC-MS), and 4) differentiated treatment according to categories that used the Restriction of Hazardous Substances in Electrical and Electronic Equipment Directive (RoHS) hazardousness threshold of 1000 mg ∑PBDEs/kg. This scheme led to the proposal of a methodology for WEEE management called the "chromoproduct approach". 994,230 products were managed and grouped into 222 chromoproducts, from which 77 were analyzed: 50 below RoHS hazardousness (BRH), 16 above RoHS hazardousness (ARH), and 11 unknown RoHS hazardousness (URH). XRF indicators using bromine and antimony contents could rule out pollution in BRH chromoproducts; however, categorization still required GC-MS. One ARH plastics sample had 3620 mg ∑PBDEs/kg, while no POP-BFRs were found in the BRH plastics sample. The implementation of the chromoproduct approach traced 153.6 tonnes of ARH plastics. BRH plastics composition was estimated and used in a pilot-scale closed-loop economic activity. The chromoproduct approach seems promising for avoiding POP-BFR releases and promoting the upcycling of recyclable e-waste plastics.

Prioritizing cardiovascular disease-associated variants altering NKX2-5 and TBX5 binding through an integrative computational approach.

Cardiovascular diseases (CVDs) are the leading cause of death worldwide and are heavily influenced by genetic factors. Genome-wide association studies have mapped >90% of CVD-associated variants within the noncoding genome, which can alter the function of regulatory proteins, such as transcription factors (TFs). However, due to the overwhelming number of single-nucleotide polymorphisms (SNPs) (>500,000) in genome-wide association studies, prioritizing variants for in vitro analysis remains challenging. In this work, we implemented a computational approach that considers support vector machine (SVM)-based TF binding site classification and cardiac expression quantitative trait loci (eQTL) analysis to identify and prioritize potential CVD-causing SNPs. We identified 1535 CVD-associated SNPs within TF footprints and putative cardiac enhancers plus 14,218 variants in linkage disequilibrium with genotype-dependent gene expression in cardiac tissues. Using ChIP-seq data from two cardiac TFs (NKX2-5 and TBX5) in human-induced pluripotent stem cell-derived cardiomyocytes, we trained a large-scale gapped k-mer SVM model to identify CVD-associated SNPs that altered NKX2-5 and TBX5 binding. The model was tested by scoring human heart TF genomic footprints within putative enhancers and measuring in vitro binding through electrophoretic mobility shift assay. Five variants predicted to alter NKX2-5 (rs59310144, rs6715570, and rs61872084) and TBX5 (rs7612445 and rs7790964) binding were prioritized for in vitro validation based on the magnitude of the predicted change in binding and are in cardiac tissue eQTLs. All five variants altered NKX2-5 and TBX5 DNA binding. We present a bioinformatic approach that considers tissue-specific eQTL analysis and SVM-based TF binding site classification to prioritize CVD-associated variants for in vitro analysis.

Prioritizing Cardiovascular Disease-Associated Variants Altering NKX2-5 Binding through an Integrative Computational Approach.

Cardiovascular diseases (CVDs) are the leading cause of death worldwide and are heavily influenced by genetic factors. Genome-wide association studies (GWAS) have mapped > 90% of CVD-associated variants within the non-coding genome, which can alter the function of regulatory proteins, like transcription factors (TFs). However, due to the overwhelming number of GWAS single nucleotide polymorphisms (SNPs) (>500,000), prioritizing variants for in vitro analysis remains challenging. In this work, we implemented a computational approach that considers support vector machine (SVM)-based TF binding site classification and cardiac expression quantitative trait loci (eQTL) analysis to identify and prioritize potential CVD-causing SNPs. We identified 1,535 CVD-associated SNPs that occur within human heart footprints/enhancers and 9,309 variants in linkage disequilibrium (LD) with differential gene expression profiles in cardiac tissue. Using hiPSC-CM ChIP-seq data from NKX2-5 and TBX5, two cardiac TFs essential for proper heart development, we trained a large-scale gapped k-mer SVM (LS-GKM-SVM) predictive model that can identify binding sites altered by CVD-associated SNPs. The computational predictive model was tested by scoring human heart footprints and enhancers in vitro through electrophoretic mobility shift assay (EMSA). Three variants (rs59310144, rs6715570, and rs61872084) were prioritized for in vitro validation based on their eQTL in cardiac tissue and LS-GKM-SVM prediction to alter NKX2-5 DNA binding. All three variants altered NKX2-5 DNA binding. In summary, we present a bioinformatic approach that considers tissue-specific eQTL analysis and SVM-based TF binding site classification to prioritize CVD-associated variants for in vitro experimental analysis.

Disease-associated non-coding variants alter NKX2-5 DNA-binding affinity.

Genome-wide association studies (GWAS) have mapped over 90 % of disease- or trait-associated variants within the non-coding genome, like cis-regulatory elements (CREs). Non-coding single nucleotide polymorphisms (SNPs) are genomic variants that can change how DNA-binding regulatory proteins, like transcription factors (TFs), interact with the genome and regulate gene expression. NKX2-5 is a TF essential for proper heart development, and mutations affecting its function have been associated with congenital heart diseases (CHDs). However, establishing a causal mechanism between non-coding genomic variants and human disease remains challenging. To address this challenge, we identified 8475 SNPs predicted to alter NKX2-5 DNA-binding using a position weight matrix (PWM)-based predictive model. Five variants were prioritized for in vitro validation; four of them are associated with traits and diseases that impact cardiovascular health. The impact of these variants on NKX2-5 binding was evaluated with electrophoretic mobility shift assay (EMSA) using purified recombinant NKX2-5 homeodomain. Binding curves were constructed to determine changes in binding between variant and reference alleles. Variants rs7350789, rs7719885, rs747334, and rs3892630 increased binding affinity, whereas rs61216514 decreased binding by NKX2-5 when compared to the reference genome. Our findings suggest that differential TF-DNA binding affinity can be key in establishing a causal mechanism of pathogenic variants.

Automation Pyramid as Constructor for a Complete Digital Twin, Case Study: A Didactic Manufacturing System.

Nowadays, the concept of Industry 4.0 aims to improve factories' competitiveness. Usually, manufacturing production is guided by standards to segment and distribute its processes and implementations. However, industry 4.0 requires innovative proposals for disruptive technologies that engage the entire production process in factories, not just a partial improvement. One of these disruptive technologies is the Digital Twin (DT). This advanced virtual model runs in real-time and can predict, detect, and classify normal and abnormal operating conditions in factory processes. The Automation Pyramid (AP) is a conceptual element that enables the efficient distribution and connection of different actuators in enterprises, from the shop floor to the decision-making levels. When a DT is deployed into a manufacturing system, generally, the DT focuses on the low-level that is named field level, which includes the physical devices such as controllers, sensors, and so on. Thus, the partial automation based on the DT is accomplished, and the information between all manufacturing stages could be decremented. Hence, to achieve a complete improvement of the manufacturing system, all the automation pyramid levels must be included in the DT concept. An artificial intelligent management system could create an interconnection between them that can manage the information. As a result, this paper proposed a complete DT structure covering all automation pyramid stages using Artificial Intelligence (AI) to model each stage of the AP based on the Digital Twin concept. This work proposes a virtual model for each level of the traditional AP and the interactions among them to flow and control information efficiently. Therefore, the proposed model is a valuable tool in improving all levels of an industrial process. In addition, It is presented a case study where the DT concept for modular workstations underpins the development of technologies within the framework of the Automation Pyramid model is implemented into a didactic manufacturing system.

Evaluating the significance of wetland restoration scenarios on phosphorus removal.

Freshwater resources are vital for human and natural systems. However, anthropogenic activities, such as agricultural practices, have led to the degradation of the quality of these limited resources through pollutant loading. Agricultural Best Management Practices (BMPs), such as wetlands, are recommended as a valuable solution for pollutant removal. However, evaluation of their long-term impacts is difficult and requires modeling since performing in-situ monitoring is expensive and not feasible at the watershed scale. In this study, the impact of natural wetland implementation on total phosphorus reduction was evaluated both at the subwatershed and watershed levels. The study area is the Saginaw River Watershed, which is largest watershed in Michigan. The phosphorus reduction performances of four different wetland sizes (2, 4, 6, and 8 ha) were evaluated within this study area by implementing one wetland at a time in areas identified to have the highest potential for wetland restoration. The subwatershed level phosphorus loads were obtained from a calibrated Soil and Water Assessment Tool (SWAT) model. These loads were then incorporated into a wetland model (System for Urban Stormwater Treatment and Analysis IntegratioN-SUSTAIN) to evaluate phosphorus reduction at the subwatershed level and then the SWAT model was again used to route phosphorus transport to the watershed outlet. Statistical analyses were performed to evaluate the spatial impact of wetland size and placement on phosphorus reduction. Overall, the performance of 2 ha wetlands in total phosphorus reduction was significantly lower than the larger sizes at both the subwatershed and watershed levels. Regarding wetland implementation sites, wetlands located in headwaters and downstream had significantly higher phosphorus reduction than the ones located in the middle of the watershed. More specifically, wetlands implemented at distances ranging from 200 to 250 km and 50-100 km from the outlet had the highest impact on phosphorus reduction at the subwatershed and watershed levels, respectively. A multi criteria decision making (MCDM) method named VIKOR was successfully executed to identify the most suitable wetland size and location for each subwatershed considering the phosphorus reduction and economic cost associated with wetland implementation. The methods introduced in this study can be easily applied to other watersheds for selection and placement of wetlands while considering environmental benefits and economic costs.

Data Integrity-A Study of Current Regulatory Thinking and Action.

In reaction to breaches of data integrity in the pharmaceutical industry, regulatory authorities have introduced inspection approaches or initiatives with the aim of reducing occurrences of data integrity problems. This review article-based on study of 65 cases of regulatory action from 2002 to 2014-provides an overview of current regulatory thinking and action on breaches of data integrity affecting GxP (health-related regulations) processes supporting non-clinical studies, clinical studies, laboratory controls, and production controls. These case studies largely represent position of the U.S. Food and Drug Administration and the regulatory agencies affiliated with the European Medicines Agency. Also discussed is the role of human factors as a potential source of data integrity problems. The article concludes by recommending some remedial controls that could be established to avoid or reduce occurrences of data integrity problems.Lay Abstract: In fulfilling their mission to protect public health, regulatory agencies (e.g., U.S. Food and Drug Administration, European Medicines Agency) must establish confidence that medical products they approve are fit for their intended use. In so doing they rely on scientific and operational data generated during research, development, manufacturing, sales, marketing, distribution, and post-marketing surveillance activities. The level of confidence they build is directly proportional to the scientific validity and integrity of data presented to them by the sponsors of medical products. In this article we present analysis of 65 case studies that document regulatory action taken by various regulatory agencies on breach of data integrity between 2002 and 2014. The ensuing discussion on current trends largely represents position of the U.S. Food and Drug Administration and European Medicines Agency. The article concludes by proposing some remedial controls that could be established by pharmaceutical companies to avoid or reduce occurrences of data integrity problems.

Network analysis of Bogotá's Ciclovía Recreativa, a self-organized multisectorial community program to promote physical activity in a middle-income country.

PURPOSE: Conduct a social network analysis of the health and non-health related organizations that participate in Bogotá's Ciclovía Recreativa (Ciclovía). DESIGN: Cross-sectional study. SETTING: Ciclovía is a multisectoral community-based mass program in which streets are temporarily closed to motorized transport, allowing exclusive access to individuals for leisure activities and physical activity. SUBJECTS: Twenty-five organizations that participate in the Ciclovía. MEASURES: Seven variables were examined by using network analytic methods: relationship, link attributes (integration, contact, and importance), and node attributes (leadership, years in the program, and the sector of the organization). ANALYSIS: The network analytic methods were based on a visual descriptive analysis and an exponential random graph model. RESULTS: Analysis shows that the most central organizations in the network were outside of the Health sector and include Sports and Recreation, Government, and Security sectors. The organizations work in clusters formed by organizations of different sectors. Organization importance and structural predictors were positively related to integration, while the number of years working with Ciclovía was negatively associated with integration. CONCLUSION: Ciclovía is a network whose structure emerged as a self-organized complex system. Ciclovía of Bogotá is an example of a program with public health potential formed by organizations of multiple sectors with Sports and Recreation as the most central.

Modeling the hydrological significance of wetland restoration scenarios.

Wetlands provide multiple socio-economic benefits, among them mitigating flood through short- and long-term water storage functions and assisting with reduction of downstream flood peaks. However, their effectiveness in controlling floods is dictated by wetland size and distribution within a watershed. Due to the complexity of wetland hydrological processes at the watershed scale, the Soil and Water Assessment Tool (SWAT) was used to study the impact of wetland restoration on streamflow rates and peaks in the Shiawassee River watershed of Michigan. Wetland restoration scenarios were developed based on combinations of wetland area (50, 100, 250, and 500 ha) and wetland depth (15, 30, 61, and 91 cm). Increasing wetland area, rather than depth, had a greater impact on long-term average daily streamflow. Wetland implementation resulted in negligible reductions in daily peak flow rates and frequency of peak flow events at the watershed outlet. In developing high impact areas for wetland restoration, similar locations were identified for reduction of subbasin and watershed outlet streamflow. However, the best combinations of area/depth differed depending on the goal of the restoration plan.

First syntheses of the biologically active fungal metabolites pestalotiopsones A, B, C and F.

A synthetic approach accessing the pestalotiopsones, fungal chromones possessing a rare skeletal subtype, is reported for the first time. The synthesis of pestalotiopsone A (1) has been achieved in 7 linear steps (28%), from commercially available 3,5-dimethoxybenzoic acid and subsequently the first syntheses of pestalotiopsone B (2), C (3) and F (4) were performed utilising this chemistry. The key steps include a newly described homologation of a substituted benzoic acid to afford phenylacetate derivatives utilising Birch reductive alkylation conditions, a microwave mediated chromanone formation proceeding through an oxa-Michael cyclisation, and an IBX induced dehydrogenation to the desired chromone skeleton. The synthetic natural products were completely characterised for the first time, confirming their structures and their biological activities evaluated against a panel of bacterial pathogens.

Next generation orthopaedic implants by additive manufacturing using electron beam melting.

This paper presents some examples of knee and hip implant components containing porous structures and fabricated in monolithic forms utilizing electron beam melting (EBM). In addition, utilizing stiffness or relative stiffness versus relative density design plots for open-cellular structures (mesh and foam components) of Ti-6Al-4V and Co-29Cr-6Mo alloy fabricated by EBM, it is demonstrated that stiffness-compatible implants can be fabricated for optimal stress shielding for bone regimes as well as bone cell ingrowth. Implications for the fabrication of patient-specific, monolithic, multifunctional orthopaedic implants using EBM are described along with microstructures and mechanical properties characteristic of both Ti-6Al-4V and Co-29Cr-6Mo alloy prototypes, including both solid and open-cellular prototypes manufactured by additive manufacturing (AM) using EBM.

Evaluation of Titanium Alloys Fabricated Using Rapid Prototyping Technologies-Electron Beam Melting and Laser Beam Melting.

This study characterized properties of Ti-6Al-4V ELI (extra low interstitial, ASTM grade 23) specimens fabricated by a laser beam melting (LBM) and an electron beam melting (EBM) system for dental applications. Titanium alloy specimens were made into required size and shape for each standard test using fabrication methods. The LBM specimens were made by an LBM machine utilizing 20 µm of Ti-6Al-4V ELI powder. Ti-6Al-4V ELI specimens were also fabricated by an EBM using 40 µm of Ti-6Al-4V ELI powder (average diameter, 40 µm: Arcam ABÒ) in a vacuum. As a control, cast Ti-6Al-4V ELI specimens (Cast) were made using a centrifugal casting machine in an MgO-based mold. Also, a wrought form of Ti-6Al-4V ELI (Wrought) was used as a control. The mechanical properties, corrosion properties and grindability (wear properties) were evaluated and data was analyzed using ANOVA and a non-parametric method (α = 0.05). The strength of the LBM and wrought specimens were similar, whereas the EBM specimens were slightly lower than those two specimens. The hardness of both the LBM and EBM specimens was similar and slightly higher than that of the cast and wrought alloys. For the higher grindability speed at 1,250 m/min, the volume loss of Ti64 LBM and EBM showed no significant differences among all the fabrication methods. LBM and EBM exhibited favorable results in fabricating dental appliances with excellent properties as found for specimens made by other fabricating methods.

Open-Cellular Co-Base and Ni-Base Superalloys Fabricated by Electron Beam Melting.

Reticulated mesh samples of Co-29Cr-6Mo alloy and Ni-21Cr-9Mo-4Nb alloy (625) and stochastic foam samples of Co-29Cr-6Mo alloy fabricated by electron beam melting were characterized by optical metallography, and the dynamic stiffness (Young's modulus) was measured by resonant frequency analysis. The relative stiffness (E/Es) versus relative density (ρ/ρs) plotted on a log-log basis resulted in a fitted straight line with a slope n ≅ 2, consistent with that for ideal open cellular materials.

Genetic characterization of the Hartón del Valle, Angus, Brangus, Holstein, and Senepol cattle breeds in Colombia, using ten microsatellite markers / Caracterización genética de las razas Hartón del Valle, Angus, Brangus, Holstein y Senepol en Colombia, usando 10 marcadores microsatélites / Caracterização genética das raças Hartón del Valle, Angus, Brangus, Holandês e Senepol na Colômbia, usando 10 marcadores microsatélites

The objective of this paper is to establish a genetic characterization of the Senepol (S, n=49), Holstein (H, n= 60), Hartón del Valle (HV, n=60), Angus (A, n=61) and Brangus (Br, n=60) cattle breeds in Colombia, by using the following microsatellite markers: SPS115, INRA64, ETH225, ETH10, BM1824, INRA37, TGLA122, TGLA126, INRA32, and BM2113. A total of 142 alleles were obtained for ten analyzed loci, considering the five cattle breeds as a whole. The number of alleles per locus ranged from 9 (INRA64 and 1824) to 22 (TGLA122). The expected heterozygosity was between 0.79 (INRA32) and 0.90 (INRA37) in all the cattle breeds, respectively; and medium heterozygosity was 0.84. The average number of alleles per breed varied from 9.2 in the Senepol breed to 10.3 in the Holstein breed. The expected heterozygosity range varied from 0.75 in the Hartón del Valle breed and 0.82 in the Holstein breed, with an average of 0.79. Hardy Wienberg disequilibrium was observed (p>0.05) when the populations were analyzed with all the markers. All the populations presented a heterozygote deficit, which could be the result of a strong endogamy tendency within all the herds. The markers used in this study allowed a genetic characterization of the analyzed populations. The microsatellites panel in the Hartón del Valle breed should be increased in order to increase the reliability value. Microsatellite panels could solve parenthood cases for the remainder breeds.

El objetivo de este trabajo fue caracterizar genéticamente las razas bovinas Senepol (S, n=49), Holstein (H, n= 60), Hartón del Valle (HV, n=60), Angus (A, n=61) y Brangus (Br, n=60) en Colombia, con los marcadores microsatélites SPS115, INRA64, ETH225, ETH10, BM1824, INRA37, TGLA122, TGLA126, INRA32 y BM2113. En total, 142 alelos fueron encontrados en los diez loci analizados, considerando las cinco razas como un todo. El número de alelos por locus estuvo entre 9 (INRA64 y BM1824) y 22 (TGLA122). La Heterocigosidad esperada a través de todas las razas varió entre 0.79 (INRA32) y 0,90 (INRA37) y heterocigosidad media esperada de 0.84. El número promedio de alelos por raza varió de 9.2 en la raza S a 10.3 en la raza H. El rango de la Heterocigosidad esperada entre las razas varió entre 0.75 en la raza HV y 0.82 en la raza H, con una media de 0.79. Al analizar las poblaciones con el total de marcadores, todas se encontraron en desequilibrio de Hardy Weinberg (p>0.05). Todas las poblaciones presentaron un déficit de heterocigotos, para todas las poblaciones, lo que podría ser el resultado de la fuerte tendencia a la endogamia dentro de los diferentes hatos. Los resultados indicaron que los marcadores utilizados en este estudio permitieron caracterizar genéticamente las poblaciones analizadas. En el caso de la Raza HV, se debe aumentar el panel de microsatélites para aumentar el valor de confiabilidad. Para las demás razas el panel de microsatélites permitiría resolver casos de filiación.

O objetivo do presente trabalho foi caracterizar geneticamente as raças Senepol (S, n=49), Holandês (H, n= 60), Hartón del Valle (HV, n=60), Angus (A, n=61) e Brangus (Br, n=60) na Colômbia, com os marcadores microsatélites SPS115, INRA64, ETH225, ETH10, BM1824, INRA37, TGLA122, TGLA126, INRA32 e BM2113. Em total, 142 alelos foram encontrados nos 10 satélites analisados nas cinco raças. O número de alelos esteve entre 9 (INRA64 e BM1824) e 22 (TGLA122). A heterocigosidade esperada a través de todas as raças variou entre 0.79 (INRA32) e 0.90 (INRA37) e heterocigosidade esperada de 0.84. O número médio de alelos por raça variou de 9.2 na raça S a 10.3 na raça H. O rango de heterocigosidade esperada entre raças variou entre 0.75 na raça HV e 0.82 na raça H, com una media de 0.79. Ao analisar as populações com o total de marcadores encontraram-se o desequilíbrio Hardy Weinberg (p>0.05). Todas as populações apresentaram um déficit de heterocigotos, o que poderia ser o resultado da forte tendência de endogamia nos diferentes rebanhos analisados. Os resultados indicaram que os marcadores utilizados em este estúdio permitiram caracterizar geneticamente as populações analisadas. No caso da raça HV deve-se aumentar o número de microsatélites para aumentar o valor de confiabilidade. Para as demais raças os microsatélites analisados permitiriam resolver casos de paternidade.

Comparación entre dos técnicas de retracción gingival para la toma de impresión definitiva en prótesis fija / Comparison between two gingival retraction techniques for taking a definitive impression in a fixed prosthesis

La retracción gingival consiste en la separación del tejido gingival con el objetivo de dejar expuestos transitoriamente las líneas de terminado talladas en la preparación de piezas dentarias. La cual desde hace algunos años, se ha realizado bajo la técnica de hilo retractor, dando muy buenos resultados, pero el tiempo empleado en ella y la difícil aplicación de esta técnica ha llevado a buscar técnicas alternativas que consigan la retracción deseada, disminuyendo estas complicaciones. Es por eso que se realizó este estudio comparativo entre dos técnicas una que habitualmente se ha usado (hilo retractor) y la otra una pasta elaborada con cloruro de aluminio y Kaolín (Expasyl). El presente trabajo de investigación comprende el análisis de 36 modelos de estudio de 18 pacientes que asistieron a las clínicas de la Facultad de Odontología de la Universidad de El Salvador en los meses de Febrero a Agosto; a los que se les tomó una impresión de control y otra después de haber aplicado las dos técnicas de retracción en estudio; posteriormente se obtuvieron los modelos en yeso extraduro, que se individualizaron y cortaron transversalmente de vestibular a lingual para su análisis. Los resultados reflejaron que en tiempo de trabajo el Expasyl se realizó en un intervalo de 4 a 6 minutos y el hilo retractor en un intervalo de 7 a 8 minutos. El hilo proporcionó un porcentaje promedio mayor de retracción de 1.62mm en comparación al Expasyl que proporcionó un promedio de 1.38mm. También se determinó que la visibilidad de la línea de terminado era mayor en el hilo retractor con un 74% de aprobación en comparación al Expasyl que presento un 56% de aprobación.

Gingival retraction consists of the separation of the gingival tissue in order to temporarily expose the finishing lines carved in the preparation of teeth. Which for some years has been carried out under the retractor wire technique, giving very good results, but the time spent in it and the difficult application of this technique has led to the search for alternative techniques that achieve the desired retraction, reducing these complications. . That is why this comparative study was carried out between two techniques, one that has been commonly used (retractor wire) and the other a paste made with aluminum chloride and Kaolin (Expasyl). The present research work includes the analysis of 36 study models of 18 patients who attended the clinics of the Faculty of Dentistry of the University of El Salvador in the months of February to August; To whom a control impression and another one were taken after having applied the two retraction techniques under study; Afterwards, the extra-hard plaster models were obtained, which were individualized and cut transversely from buccal to lingual for analysis. The results reflected that in working time the Expasyl was performed in an interval of 4 to 6 minutes and the retractor wire in an interval of 7 to 8 minutes. The thread provided a higher average percentage of shrinkage of 1.62mm compared to Expasyl which provided an average of 1.38mm. It was also determined that the visibility of the finishing line was higher in the retractor cord with a 74% approval compared to the Expasyl that presented a 56% approval.

Growth modelling indicates hurricanes and severe storms are linked to low coral recruitment in the Caribbean.

This study set out to test the hypothesis that hurricanes and tropical storms limit the recruitment and subsequent survival of massive non-branching corals on the barrier reef off the coast of Belize in the Gulf of Honduras. Overall, the surface areas of 523 individual coral specimens were measured, and recruitment dates were then modelled. There was no significant difference in coral cover or coral biodiversity between any of the sites studied (p > 0.1). There were significant differences in non-branching coral recruitment in years when hurricanes impacted the area (p < 0.05) compared with years when no hurricanes impacted the area. There were significantly more non-branching massive corals recruited in non-hurricane years (mean 7.7) than in hurricane years (mean 3.8; p = 0.011). When years with tropical storms are added to the years with hurricanes, there was significantly lower coral recruitment (mean 4.7) relative to non-storm or hurricane years (mean 7.4; p = 0.019). These results show that hurricanes and severe storms limited the recruitment and survival of massive non-branching corals of the Mesoamerican barrier reef and on patch reefs near the Belize coast in the Caribbean, and suggests that marine park managers may need to assist coral recruitment in years where there are hurricanes or severe storms.

REEMPLAZO DE UN DIENTE ANTEROSUPERIOR MEDIANTE UN CERROJO Y RESINA COMPUESTA

Aplicando correctamente esta técnica cumple un propósito fundamental el de preservar estructuras de tarias, optimizando la condición fisiológica y el comportamiento masticatorio del "Sistema Oral".Se confeccionan en todo tipo de paciente. Su elaboración no es traumatica. Solo debe limitarse al sector anterior, y cuando falta una sola pieza dentaria. Se consigue una mejor estética mediante la restauración de la forma, función armonia, color de la pieza dentaria