Federal University of Rio de Janeiro

In this paper, we investigate three main aspects concerning a quasi-linear parabolic equation with a semilinear term in dimensions 2 and 3: the local null controllability with distributed controls, the decay of solutions in H 3 (Ω), and the null controllability for large times. In addition to the theoretical results, we present numerical methods to solve the aforementioned problems. These techniques employ an iterative quasi-Newton method combined with the Finite Element Method. The corresponding algorithms are implemented using the FreeFem++ software. The results of the numerical simulations are illustrated through figures and comparative graphs.

Hysteretic response of smart materials has complex mathematical modeling. Thermodynamic-based constitutive models belong to an important class of models and data-driven models are interesting alternatives that avoid complex algorithms and parameter determinations. The classical Preisach model describes multidisciplinary hysteretic behavior employing mathematical operators in a triangular domain. The Everett function is an alternative build a surface from experimental data, replacing the original integral form to a summation. This paper proposes a novel approach, extending the Preisach triangular domain to a prismatic domain that allows a broader description of distinct phenomena. The idea is to use the Preisach approach for different triangles and then performing a interpolation for a prismatic domain, enabling the representation of distinct phenomena that, otherwise would not be described. Shape memory alloys (SMAs) are employed as a representative example of smart materials. Experimental tests are developed in order to define reference cases to be analyzed. Numerical simulations are carried out and compared with experimental data, evaluating the model capabilities under different loading conditions. Specifically, temperature-dependent and cyclic-dependent behaviors are of concern. The results show the model ability to describe the general thermomechanical behavior of shape memory alloy hysteretic behavior, being in close agreement with experimental data.

Background One significant challenge to food security is the expansion of salt-affected soils. Current soil recovery methods are technically or economically unfeasible in extensive arid regions. Phytoremediation, the use of plants to rehabilitate contaminated environments, is a promising, low-cost alternative. This study aimed at enhancing the growth and biomass accumulation of the halophyte Atriplex nummularia through inoculation with plant growth-promoting bacteria. Methods An integrated approach to select endophytic bacteria was used, combining culture-dependent and culture-independent techniques. Over 700 bacterial strains were isolated and screened for plant growth-promoting traits such as phosphate solubilization, indolic acid production, nitrogen fixation and stress alleviation. Then, root and leaf bacterial consortia were formulated to enhance plant growth and phytoremediation efficiency. A greenhouse experiment was carried out to assess the impact of these consortia on A. nummularia seedlings in saline soil conditions for 120 days. The design included four treatments: control (no inoculation), root inoculation, leaf inoculation, and combined root and leaf inoculation. Results Results showed that bacterial inoculation significantly improved plant growth and biomass yield. Leaf-inoculated plants showed enhanced sodium removal from the soil, indicating improved soil conditions. Endophytic bacteriome analysis revealed that inoculation slightly altered the bacterial community composition in both roots and leaves. These changes were most pronounced in the combined inoculation treatment, suggesting a cooperative interaction between root and foliar bacteria, affecting the plant bacteriome. Conclusion This study highlights the potential of using plant growth-promoting bacteria to enhance the phytoremediation capabilities of A. nummularia, offering an improved strategy for the sustainable management of saline soils. Graphical Abstract

Let XX be a K3 surface admitting a non‐symplectic automorphism σ$\sigma$ of order 3. Building on work by Garbagnati and Salgado, we classify the Jacobian elliptic fibrations on XX with respect to the action of σ$\sigma$ on their fibers. If the fiber class of a Jacobian elliptic fibration on NS(X)$\operatorname{NS}(X)$ is fixed by σ$\sigma$, we determine the possible configurations of its singular fibers and present the equation for its generic fiber. When the Picard number of XX is at least 12 and σ$\sigma$ acts trivially on NS(X)$\operatorname{NS}(X)$, we apply the Kneser–Nishiyama method to find its Jacobian elliptic fibrations up to J2$\mathcal {J}_2$‐equivalence. We use our method to classify them with respect to any non‐symplectic automorphism of order 3 in Aut(X)$\operatorname{Aut}(X)$.

Coastal plains are low-lying sedimentary landscapes with terraces parallel to the sea that support numerous wetlands. Human activity limits our ability to recognize them as vast coastal wetlands with macrohabitats linked by water and biodiversity. Our hypothesis is that surface water connects across the coastal plain because of morphology, hydrology, climate, and human activity. The purpose of this study is to investigate surface water connections across the Norte Fluminense coastal plain using hydro-morphometric characterization, as well as the interaction between long-term water surface, climate parameters, and human management. We used remote sensing analysis, morphologic and hydrologic indices, rainfall and evaporation data from models and meteorologic stations, and information about human management to describe the water connectivity across the coastal plain. The coastal plain has a larger water surface area, number of flooded patches and short average distance between flooded patches during the rainy years, suggesting surface water connectivity across the coastal plain. There is a strong correlation between the flooded area and rainfall and evapotranspiration. Human management can either maintain the water connections (protected areas, for example) or disrupt them (opening lagoon sandbars). This coastal plain should be analyzed as a connected catchment-wetland system, since our hydro-geomorphological classification suggests hydrological and ecological connection when compared to other wetlands. Therefore, our results demonstrate that, depending on hydrological parameters and connectivity, coastal plains can be categorized as large coastal wetland; however, other factors like biodiversity must also be considered.

Hepatic fibrosis resulting from human mansonic schistosomiasis significantly impairs liver function and contributes substantially to morbidity associated with helminth infections. This pathological state develops following the deposition of helminth eggs within hepatic tissues, triggering a granulomatous inflammatory reaction. Schistosomiasis, a neglected tropical disease affecting approximately 240 million individuals globally, represents a major public health challenge. Although praziquantel (PZQ) is recommended by the World Health Organization (WHO) as the primary treatment for helminth infections, additional therapies are required to address the associated liver fibrosis. This study investigated the efficacy of tetramethylpyrazine (TMP), a natural compound known for its anti-inflammatory, antifibrotic, and hepatoprotective properties in various experimental models, in mitigating hepatic fibrosis induced by mansonic schistosomiasis. Our in vivo experiments demonstrated that TMP treatment significantly reduced hepatic granuloma size, as evidenced by histological analysis. Furthermore, our in vitro studies showed that TMP increased levels of the anti-inflammatory cytokine IL-10 while decreasing levels of the profibrotic cytokine IL-13 in a concentration-dependent manner. Immunofluorescence analysis also revealed that TMP effectively inhibited collagen deposition. Collectively, these findings suggest that TMP exhibits potential as an anti-inflammatory and antifibrotic agent for hepatic fibrosis resulting from Schistosoma mansoni infection. Graphical abstract

Mycobacterium kansasii (Mkan) is a nontuberculous mycobacterium (NTM) commonly found in aquatic environments and is responsible for chronic pulmonary infections resembling tuberculosis. Treatment requires multiple antibiotics for at least 12 months, highlighting the challenge in managing Mkan infections. In this study, 50 thiourea derivatives were synthesized and evaluated for their cytotoxic and inhibitory effects on bacterial growth in culture and in infected macrophages using Mkan strains with varying virulence levels. In silico studies explored the structure–activity relationship (SAR) and the pharmacokinetic and toxicological profiles of the most active thiourea derivatives. As a result, 15 derivatives showed promising inhibitory activity against the reference strain, Mkan 12478. Of these, derivatives 2, 47, and 49 also significantly inhibited clinical isolates 10953 and 8835 without displaying cytotoxic effects. Furthermore, these three derivatives could inhibit intracellular mycobacterial growth in RAW 264.7 macrophages infected with strains 12478 or 8835. SAR studies revealed molecular volume and polar surface (PSA) area as important features for these thiourea derivatives, directly correlating with their antimycobacterial profile. In silico studies indicated that these compounds are potentially suitable for oral administration and have less toxicological effects than rifampicin, providing a safer alternative for antimycobacterial treatment. In conclusion, our findings suggest that thiourea derivatives 2, 47, and 49 are promising antimycobacterial agents for treating infections caused by Mkan.

This study explored the potential for performance enhancement using a Ru(III) salophen-type Schiff base complex as a co-catalyst in conjunction with PtSn/C for ethanol electro-oxidation. This type of compound is recognized as a cost-effective synthetic catalyst for oxidation reactions, which can improve the electrocatalytic activity of platinum-based catalysts while remaining less expensive. The ligand and complex were synthesized and characterized using various techniques, including FTIR and UV–vis spectroscopies, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. Electrocatalytic experiments revealed that the mixed catalyst PtSn/C:[Ru(ndsp)(Cl)(H₂O)] at a mass ratio of 4:1—comprising 20% of the catalyst mass—outperformed pure PtSn/C. It achieved a peak current density of 32.5 mA/cm², approximately 1.7 times higher than that of pure PtSn/C, and the onset potential for the ethanol oxidation reaction occurred at a less positive value. Maximum catalytic efficiency was observed at a pH of 0.3 and increased with higher ethanol concentrations. These results indicate that the addition of the Ru(III) complex significantly enhances the catalytic activity of PtSn/C, making it a promising and cost-effective candidate catalyst system for direct ethanol fuel cell (DEFC) applications. Graphical Abstract

The focus of this paper is on the introduction of uncertainty on structural properties, stiffnesses and masses, of linear finite element models for dynamic analyses. The novelty of the presented approach is that the uncertainty is introduced at the “elemental” level, i.e., directly on the mass and stiffness matrices of the various elements of the model by an appropriate randomization of the corresponding matrices obtained for a nominal model. Thus, the uncertainty modeling effort can be conducted out of core of a finite element software which could be a commercial one. The present effort deepens and extends earlier papers by the authors that addressed the modeling of elemental stiffness matrices only. First, the condition of independence with respect to the element node ordering suggested in the previous papers is mathematically derived here. Then, the physical constraints existing on elemental mass matrices are described and a dedicated modeling strategy of these matrices is derived that satisfies the constraints for all types of elements. The approach is finally applied to a structure that exhibits a strong sensitivity to structural uncertainties and a parametric study of the uncertainty levels in stiffness and in mass is conducted to highlight their effects on the natural frequencies, mode shapes and frequency response functions of the test structure.

Background Osseous reconstructive surgery for hip displacement in children with cerebral palsy (CP) consists of proximal femoral reorientation by varus derotational osteotomy (VDRO) combined with pelvic osteotomy when indicated. The rate of recurrent hip instability after the index surgery can be as high as 77%. We evaluated the association between femoral diaphyseal medialization at the VDRO site and recurrent instability. We hypothesized that medialization may modify the hip joint reaction force (HJRF), reducing the femoral remodeling that leads to recurrent coxa valga and instability. Methods A retrospective evaluation of the clinical and radiographic records of 140 patients (280 hips) with CP, Gross Motor Function Classification System (GMFCS) Level IV or V, who had been treated with bilateral VDRO as the index surgery for hip displacement between 1998 and 2012 (mean follow-up, 11.3 years) was conducted. Radiographic measurement of medialization was performed using the medialization index (MeI) preoperatively, at 6 weeks and 12 months postoperatively, and at skeletal maturity. Recurrent instability was defined as the need for revision surgery before skeletal maturity or a final migration percentage (MP) of >40%. The influence of the MeI was determined by Poisson regression with multiple variances. The inter- and intra-observer reliability of the MeI, measured by 4 different observers, was assessed using the Cohen d test. Results Groups with and without relapse were comparable preoperatively regarding femoral and acetabular parameters. The baseline MP was higher in the relapse group (p < 0.001). The MeI at 6 weeks postoperatively was significantly lower in the relapse group (p = 0.004, relative risk [RR] = 0.07, 95% confidence interval [CI] = 0.01 to 0.42) than in the no-relapse group in multivariable analysis. The MeI showed good inter- and intra-observer reliability, with a Cohen d of <0.5. Conclusions Patients with greater medialization had lower rates of recurrent hip instability at long-term follow-up. The MeI proved to be reliable as a radiographic measurement, and medialization did not increase mechanical instability. Level of Evidence Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Flax fibers have attracted growing interest in the automotive industry as an eco-friendly reinforcement for polymer composites. However, their limited interfacial compatibility with hydrophobic matrices is detrimental to adhesion, a key factor in the composite mechanical behavior. To address this issue, this study investigates the surface modification of flax fibers using sulfur hexafluoride (SF6) plasma. The proposed treatment promotes fiber surface hydrophobization while preserving their bulk properties. The effect of SF6 plasma treatments on flax fiber adhesion to polypropylene (PP) blends containing post-consumer material is thoroughly examined. The analysis, conducted using scanning electron microscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, and infrared spectroscopy, reveals that the plasma treatment induces the etching of amorphous substances present in the fibers, including amorphous cellulose, hemicelluloses, and lignin. Plasma etching in combination with fluorination significantly enhances the adhesion of flax fibers to the PP blend matrix. Notably, the treated fibers exhibit improvements in tensile strength (9%) and elastic modulus (25%) compared to untreated fibers. These findings highlight the potential of SF6 plasmas as an effective pretreatment method for natural fiber composite reinforcements.

This work discusses the influence of galaxy mergers in the evolution of a parabolic Lemaître–Tolman–Bondi (LTB) cosmology with simultaneous big bang endowed with two consecutive single fractal galaxy distributions systems possessing fractal dimension D . Based on recent empirical findings, it is assumed that the resulting galaxy mass from mergers can be expressed by a redshift dependent decaying power law. The proposed cosmological model modifies the relativistic fractal number counts distribution by including a merger rate evolution that estimates the model’s radial density. Numerical solutions for the first order small-merger-rate approximation (SMRA) are found and the results show that a fractal galaxy distribution having D=1.5 D = 1.5 in the range $0.1 0.1 < z < 1.0 , and$D=0.5$D = 0.5 for$1 1 < z < 6 , as suggested by recent empirical findings, the SMRA allows consistent description of the model for a merger rate power law exponent up to q=0.2 q = 0.2 considering a fractal galaxy distribution starting from the Local Group. Consistent values were also found up to q=2.5 q = 2.5 and z=7 z = 7 from a scale smaller than the Local Supercluster. These results show that galaxy mergers can be successfully incorporated into the dynamics of a parabolic LTB fractal cosmology.

Physician-scientists, who have dual medical and advanced research training, are a scarce and valuable asset. They bridge clinical practice and research, address critical medical challenges with a scientific perspective, and drive innovation by translating discoveries into patient care. Physicians with research expertise are particularly adept at critically evaluating scientific literature to improve their practice and ensure that they provide up-to-date, individualised, and evidence-based care to their patients. However, the path to becoming a physician-scientist in Low- and Middle-Income Countries (LMICs) is fraught with challenges. In this article, we explore the difficulties faced by physician-scientists in LMICs, including lengthy and arduous training, systems that favour eminence-based over evidence-based medicine, and financial disincentives for pursuing a dual career in medicine and research. The article also highlights the significant underrepresentation of women in medical and scientific fields, compounded by gender-specific challenges such as balancing motherhood with career demands, gender pay gaps, and the lack of supportive and affirmative policies. We advocate for reforms in medical education to create a more supportive environment for aspiring physician-scientists. Addressing these issues can help LMICs enhance the contribution of physician-scientists to global health and scientific advancement.

Ecosystem restoration is a global priority for recovering degraded areas and mitigating climate change. However, climate change can impact the long-term effectiveness of restoration efforts. This study evaluated the effects of climate change on restoration planning, focusing on water quality in the Doce River basin, the site of Brazil’s largest environmental tragedy and the most significant mining disaster globally, with the release of approximately 50 million cubic metres of iron ore tailings into the environment. Sediment exportation was used as a criterion for assessing water quality under three climate scenarios. Restoration of riparian vegetation reduced sediment exportation by 75.29% but was insufficient to fully control erosion, particularly in the upper basin, where increased precipitation could exacerbate the problem. The findings underscore the risks of ignoring climate change in restoration planning. Adaptive strategies are essential to ensure long-term benefits and address climate challenges, fostering more resilient and sustainable ecosystems.

Instruments are susceptible to deformation and/or fracture, which may represent a failure in endodontic treatment. This study assessed the mechanical properties of nickel-titanium rotary instruments through cyclic fatigue, buckling resistance, and 45° bending tests. One hundred and twenty rotary instruments were divided into three groups: Super Flexi Files Blue (SFB; 20/.04), TruNatomy Small (TN; 20/.04), and ProTaper Ultimate Shaper (PTU; 20/.04). They underwent cyclic fatigue tests at fixed and manufacturer-specified speeds, along with buckling and bending tests. SFB files exhibited the greatest cyclic fatigue resistance with the longest time to fracture and highest number of cycles to failure (NCF), followed by TN and PTU. For PTU and TN, reducing rotation speed increased time to fracture and NCF, while SFB showed reduced values with speed increase. TN exhibited the highest buckling resistance, whereas PTU had superior performance in the bending test. Rotation speed significantly affected cyclic fatigue resistance, with SFB being the most resistant overall. TN demonstrated notable buckling resistance and flexibility. The rotational speed significantly affects the resistance of instruments to cyclic fatigue and that the SFB file is the most resistant file to cyclic fatigue. The TN file proved to be the most resistant and flexible.

Cannabidiol (CBD), a non-psychoactive cannabinoid with therapeutic potential, is increasingly used in combination with other drugs, raising concerns about potential interactions and their impact on safety and efficacy. This scoping review aimed to map the current evidence on CBD interactions across different drug classes and assess their clinical significance. The study followed the Joanna Briggs Institute guidelines, utilizing a structured protocol based on the Population, Concept, and Context (PCC) framework. Five databases were searched, and preclinical and clinical studies on CBD pharmacokinetic and pharmacodynamic interactions were included, with publications in English, Portuguese, or Spanish. Out of 136 studies analyzed, 91.91% were published after 2011, reflecting a sharp rise in interest in this area. A total of 271 interactions were identified, with 203 related to pharmacokinetics, primarily involving metabolism mediated by cytochrome P450 (CYP) enzymes, and 68 linked to pharmacodynamics, including additive effects such as sedation. Among the most relevant findings, CBD was shown to inhibit CYP enzymes like CYP3A4 and CYP2C19, potentially increasing plasma levels of co-administered drugs. However, only 5.15% of studies evaluated the clinical relevance of these interactions, indicating a substantial gap in knowledge regarding their safety implications. This review highlights the urgent need for rigorous clinical research to determine the clinical significance of CBD-drug interactions, particularly in patients undergoing polypharmacy. Understanding these interactions is crucial for optimizing therapeutic outcomes, minimizing adverse effects, and enabling safer clinical use of CBD in diverse treatment regimens.