Universidade Federal do Rio de Janeiro

Evaluating zinc bioavailability in dredged sediments of Guanabara bay (BRAZIL): implications for coastal management standards

Abstract Guanabara Bay (GB) is an environment contaminated by metals, and it is the bay that receives the most dredging in Brazil and South America. Previous studies have shown the impact of dredging on planktonic and benthic species, which were not correctly measured by the Braz...

Early stages of thermo-oxidative aging of EPDM composites: Effect of aging temperature

The increasing generation of post-consumer rubber waste highlights the need to better understand aging mechanisms to develop more durable composites with extended service life. This study investigates the early stages of thermo-oxidative aging of ethylene-propylene-diene monomer...

Sliding Trajectories of Generic Inelastic Piecewise-Linear Dynamical Systems on the Torus

Abstract We consider piecewise smooth differential equations $$Z_{X_-X_+}$$ Z X - X + , where $$X_-$$ X - and $$X_+$$ X + are linear inelastic vector fields on $$\mathbb {R}^3$$ R 3 with the torus as the discontinuity manifold. Under suitable assumptions, we classify the tangency...

A Single‐Aliquot Strategy for Simultaneous Carbon Isotope Confirmation of 6‐Oxo‐Androstenedione and Testosterone Misuse in Doping Control

ABSTRACT A method compliant with World Anti‐Doping Agency (WADA) requirements was validated for carbon isotope ratio (CIR) analysis enabling the simultaneous confirmation of 6‐oxo‐androstenedione (6‐oxo) metabolites and testosterone steroid profile markers from a single urine sam...

Large-deformation theoretical analysis of open-end thick-walled tubes under internal pressure

Subsea pipelines and deepwater risers are critical components in offshore oil and gas production, often subjected to extreme internal pressure during operation and hydrotesting. This study proposes a rigorous theoretical model for stress-strain analysis on open-end thick-walled c...

Complete Reporting for Transparent Reproducibility Efforts (CORTRE)

The CORTRE project develops a consensus-based reporting guideline for reproduciblity efforts -- projects that systematically re-examine previously published findings to investigate an aspect of their reproducibility. The project was launched at the Responsible Research in Action...

Land transformation driven by wind and solar development in Brazilian municipalities

Abstract In the last decade, Brazil’s energy sector has been moved from an exclusively hydroelectric and thermal mix to incorporate large-scale production of wind and solar photovoltaic energy. This energy transition is synchronized with the global imperative to reduce greenhouse...

Untargeted LC-HRMS/MS and Feature-Based Molecular Networking Reveal Distinct Metabolic Signatures in Edible Dahlia Types

Abstract Edible flowers represent chemically diverse food matrices whose characterization increasingly relies on advanced metabolomic approaches. This study employed untargeted liquid chromatography–high-resolution tandem mass spectrometry (LC-HRMS/MS) combined with feature-based...

Academic achievement map: a clear cognitive route and a promising motor path

OBJECTIVE: This study investigates how executive functions, motor coordination, and oral discourse are related to academic performance in children from public schools in Rio de Janeiro. METHOD: This longitudinal study assessed 75 children at the beginning (T1) and at the end (T2)...

Large magnetocaloric effect in the EuSe1− x S x magnetic semiconductors with coexistence of the magnetic phases

We present the experimental results of the magnetic and calorimetric properties as well as the magnetocaloric effect of the EuSe1−xSx compounds with x = 0, 0.10, 0.16, 0.18, and 1. Magnetic and calorimetric results reveal complex low-temperature magnetic behavior arising from com...

Habitat Complexity and Seasonal Variation Factors Shape the Polychaete Assemblies Associated with the Holdfast of Lessonia berteroana

Lessonia berteroana is a structuring macroalga that houses a high diversity of benthic invertebrates in southeastern Pacific rocky ecosystems. The present study assessed the diversity and structure of the community of polychaetes associated with the holdfast of L. berteroana at t...

Mercury in Fish from Guanabara Bay, Southeast Brazil: Tissue-Specific Accumulation and Human Health Risks

Abstract Guanabara Bay is Brazil’s second-largest bay and has a long history of intense industrial and domestic pollution. Some local communities rely on fish as a primary protein source, justifying an assessment of mercury (Hg) contamination. This study determined total mercury...

SNP-based genomic variation in candidate disease resistance genes of Theobroma cacao

Abstract Theobroma cacao is a species with high economic value whose production is impaired by multiple factors, including yield losses caused by pathogens such as Moniliophthora perniciosa , Phytophthora spp., Ceratocystis cacaofunesta , and Moniliophthora roreri . In this conte...

Development of Recombinant Multi-Epitope Hepatitis C Virus (HCV) Protein for Hepatitis C Diagnosis

Hepatitis C virus (HCV) infection poses a major challenge to global public health, highlighting the need for accessible and reliable diagnostic tools to support large-scale screening and early detection. In this study, a recombinant multi-epitope HCV protein was designed, express...

Global Paid and Unpaid Productivity Losses Due to Gastrointestinal Cancer Mortality

OBJECTIVES: Gastrointestinal (GI) cancers contribute substantially to premature mortality, yet their full economic burden, including unpaid work, remains underquantified. We aimed to estimate global productivity losses attributable to GI cancer mortality, considering paid and unp...

The Spiritual Dimension of Palliative Care Patients and Their Caregivers in a Compassionate Community in Two Brazilian Favelas1: A Mixed-Methods Study

Abstract Spirituality is a key dimension of palliative care, contributing to well-being, supporting adjustment to illness, and serving as an important coping resource for patients and caregivers. In socially vulnerable settings, compassionate community initiatives may facilitate...

Evaluation of the slag generated during steel production as a culture medium for the obtaining of Spirulina maxima biomass

Abstract The use of cyanobacteria in the context of biofertilizers allows the strategic valorization of aquatic biomass as a bioinput for application in agriculture, since cyanobacteria have both biofertilizer and biostimulant capacity. Furthermore, the use of a residue such as s...

Floral dynamics in the protandrous flowers of Bauhinia variegata (Fabaceae): phase-specific morphology, scent, and nectar production

Abstract Main conclusion Protandry in Bauhinia variegata is expressed through coordinated changes in floral morphology, scent composition, secretory activity, and nectar presentation, whereas petal reflectance remains stable; molecular docking further indicates that key phase-ass...

Congenital Syphilis in Brazil: Municipal Antenatal Care, Primary Health Care Capacity, and Territorial Inequalities, 2015–2024

Abstract Objectives To describe spatial patterns of gestational (GS) and congenital syphilis (CS) in Brazil and assess municipal antenatal care, sociodemographic, and primary-care correlates of CS notifications after accounting for GS burden. Methods We conducted a nationwide eco...

Metal geochemistry in bottom sediments from an urbanized tropical estuary: implications for land disposal of dredged materials

Abstract The Fundão canal (RJ/Brazil) is an urbanized estuary impacted by eutrophication, metal contamination and silting, and was subjected to dredging operations to fulfill the demands of the 2016 Olympic Games. Given the scarcity of studies focused on the degradation of tropic...