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1.
Cancers (Basel) ; 16(11)2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38893254

RESUMO

Basal Cell Carcinoma (BCC) is the most common type of cancer among the white population. Individuals with fair skin have an average lifetime risk of around 30% for developing BCC, and there is a noticeable upward trend in its incidence rate. The principal treatment objectives for BCC involve achieving the total excision of the tumor while maximizing the preservation of function and cosmesis. Surgery is considered the treatment of choice for BCC for two main reasons: it allows for the highest cure rates and facilitates histological control of resection margins. However, in the subgroup of patients with low-risk recurrence or medical contraindications for surgery, new non-surgical treatment alternatives can provide an excellent oncological and cosmetic outcome. An evident and justified instance of these local therapies occurred during the COVID-19 pandemic, a period when surgical interventions carried out in hospital settings were not a viable option.

2.
Adv Skin Wound Care ; 37(6): 1-8, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38767428

RESUMO

BACKGROUND: In the literature, there is no consensus regarding the surgical management of postaxial polydactyly, and few cases of polymetatarsia with polydactyly have been reported. Treatment of the complete deformity will prevent further foot and gait disorders. OBJECTIVE: To identify literature relevant to the operative management of Y-shaped metatarsal with biphalangeal sixth toe and related skin and wound care to improve surgical treatment protocols from a clinical experience perspective. DATA SOURCES: The authors searched several electronic databases in December 2022 for articles related to postaxial polysyndactyly in the feet and polymetatarsia. Databases searched included PubMed, SciELO, ScienceDirect, Cochrane Database of Systematic Reviews, and Google Scholar gray literature. STUDY SELECTION: Two independent researchers conducted the searches and read the article titles and abstracts. Studies were included if they were narrative reviews, case studies, or observational studies; written in English or Spanish; and published between 2012 and 2022. Nonhuman studies were excluded. Studies that met the inclusion criteria were fully evaluated. Disagreements between reviewers were resolved by consensus, and when there was no consensus, a senior researcher was consulted. DATA EXTRACTION: The following data were extracted from the included studies using a standardized form: author and year of publication, study type, number of participants, sex, polydactyly location, polymetatarsia, type of polydactyly, participants' history of hereditary associated diseases or malformations, treatment, removal criteria, and timing of surgery. DATA SYNTHESIS: Authors evaluated 11 studies of postaxial polydactyly that included a total of 153 participants (64 men, 89 women). They also document their clinical experience with a surgical technique used in cases of bilateral postaxial polydactyly of the foot with a Y-shaped metatarsal with biphalangeal sixth toe. CONCLUSIONS: Surgical correction with lateral removal of the sixth toe is a resolutive treatment to improve the functionality of the foot, its aesthetic appearance, and the patient's quality of life. Case-specific treatment should be applied and tailored to meet the individual needs. The biomechanics of gait and shoe problems in these patients improve with surgical treatment, without presenting secondary aesthetic problems in skin care.


Assuntos
Ossos do Metatarso , Polidactilia , Humanos , Ossos do Metatarso/anormalidades , Ossos do Metatarso/cirurgia , Polidactilia/cirurgia , Dedos do Pé/anormalidades , Dedos do Pé/cirurgia , Feminino , Masculino , Dedos/anormalidades
3.
J Orthop ; 54: 136-142, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38567192

RESUMO

Background: Syndesmotic injuries are frequently stabilized using syndesmotic screws. Traditionally, these screws were routinely removed during the postoperative period, however recent literature has brought into question the necessity of routine removal, citing no change in functional outcomes and the inherent risks of a second surgery. Our study aimed to compare outcomes of patients undergoing routine syndesmotic screw removal versus those undergoing an on-demand approach to removal. Methods: A systematic search of studies comparing routine syndesmotic screw removal to on-demand screw removal following an acute ankle fracture, or an isolated syndesmotic injury was conducted across seven databases. Only Prospective randomized controlled trials were eligible for inclusion. Data reported on by at least 2 studies was pooled for analysis. Results: Three studies were identified that met inclusion and exclusion criteria. No significant difference in Olerud-Molander Ankle Score (MD -2.36, 95% CI -6.50 to 1.78, p = 0.26), American Orthopedic Foot and Ankle Hindfoot Score (MD -0.45, 95% CI -1.59 to .69, p = 0.44), or dorsiflexion (MD 2.20, 95% CI -0.50 to 4.89, p = 0.11) was found between the routine removal group and on-demand removal group at 1-year postoperatively. Routine removal was associated with a significantly higher rate of complications than on-demand removal (RR 3.02, 95% CI 1.64 to 5.54, p = 0.0004). None of the included studies found significant differences in pain scores or range of motion by 1-year postoperatively. Conclusion: Given the increased risk of complications with routine syndesmotic screw removal and the comparable outcomes when screws are retained, an as-needed approach to syndesmotic screw removal should be considered.

4.
Clin Exp Dermatol ; 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38531692

RESUMO

BACKGROUND: Topical imiquimod has shown to be an effective treatment for EMPD, although available evidence supporting its use is based on case reports and small series of patients. OBJECTIVES: To investigate the therapeutic outcomes and analyze potential clinico-pathological factors associated with imiquimod response in a large cohort of EMPD patients. METHODS: Retrospective chart review of 125 EMPD patients treated with imiquimod at 20 Spanish tertiary-care hospitals. RESULTS: During the study period, patients received 134 treatment regimens with imiquimod, with 70 (52.2%) cases achieving complete response (CR), 41 (30.6%) partial response and 23 (17.2%) no response. The cumulative CR rates at 24 and 48 weeks of treatment were 46.3% and 71.8%, respectively, without significant differences between first-time and previously treated EMPD. Larger lesions (≥6 cm; p = 0.038) and EMPD affecting >1 anatomical site (p = 0.002) were significantly associated with a worse treatment response. However, the CR rate did not differ significantly by the number of treatment applications (≤4 vs. > 4 times/week; p = 0.112). Among patients who achieved CR, 30 (42.9%) developed local recurrences during a mean follow-up period of 36 months, with an estimated 3 and 5-year recurrence free-survival of 55.7% and 36.4%, respectively. CONCLUSIONS: Imiquimod appears as an effective therapeutic alternative for both first-line and previously treated EMPD lesions. However, a less favorable therapeutic response could be expected in larger lesions and those affecting >1 anatomical site. Based on our results, a 3-4 times weekly regimen of imiquimod with a treatment duration of at least 6 months could be considered an appropriate therapeutic strategy for EMPD patients.

5.
J Environ Sci (China) ; 140: 230-241, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38331503

RESUMO

Cigarette butts (CBs) are one of the most common types of litter in the world. Due to the toxic substances they contain, the waste generated poses a harmful risk to the environment, and therefore there is an urgent need for alternative solutions to landfill storage. Thus, this work presents a possible revalorization of this waste material, which implies interesting environmental benefits. CBs were used as sacrificial templates for the preparation of CaO-based materials by impregnation with calcium and magnesium nitrates followed by flaming combustion. These materials presented enhanced porosity for their use in the Calcium Looping process applied either to thermochemical energy storage or CO2 capture applications. The influence of the concentration of Ca and Mg in the impregnating solutions on the multicycle reactivity of the samples was studied. An improved multicycle performance was obtained in terms of conversion for both applications.


Assuntos
Dióxido de Carbono , Produtos do Tabaco , Dióxido de Carbono/química , Cálcio , Resíduos , Fenômenos Físicos
6.
Microbiol Spectr ; 12(2): e0292823, 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38189292

RESUMO

The genus Vibrio includes pathogenic bacteria able to cause disease in humans and aquatic organisms, leading to disease outbreaks and significant economic losses in the fishery industry. Despite much work on Vibrio in several marine organisms, no specific studies have been conducted on Anadara tuberculosa. This is a commercially important bivalve species, known as "piangua hembra," along Colombia's Pacific coast. Therefore, this study aimed to identify and characterize the genomes of Vibrio isolates obtained from A. tuberculosa. Bacterial isolates were obtained from 14 A. tuberculosa specimens collected from two locations along the Colombian Pacific coast, of which 17 strains were identified as Vibrio: V. parahaemolyticus (n = 12), V. alginolyticus (n = 3), V. fluvialis (n = 1), and V. natriegens (n = 1). Whole genome sequence of these isolates was done using Oxford Nanopore Technologies (ONT). The analysis revealed the presence of genes conferring resistance to ß-lactams, tetracyclines, chloramphenicol, and macrolides, indicating potential resistance to these antimicrobial agents. Genes associated with virulence were also found, suggesting the potential pathogenicity of these Vibrio isolates, as well as genes for Type III Secretion Systems (T3SS) and Type VI Secretion Systems (T6SS), which play crucial roles in delivering virulence factors and in interbacterial competition. This study represents the first genomic analysis of bacteria within A. tuberculosa, shedding light on Vibrio genetic factors and contributing to a comprehensive understanding of the pathogenic potential of these Vibrio isolates.IMPORTANCEThis study presents the first comprehensive report on the whole genome analysis of Vibrio isolates obtained from Anadara tuberculosa, a bivalve species of great significance for social and economic matters on the Pacific coast of Colombia. Research findings have significant implications for the field, as they provide crucial information on the genetic factors and possible pathogenicity of Vibrio isolates associated with A. tuberculosa. The identification of antimicrobial resistance genes and virulence factors within these isolates emphasizes the potential risks they pose to both human and animal health. Furthermore, the presence of genes associated with Type III and Type VI Secretion Systems suggests their critical role in virulence and interbacterial competition. Understanding the genetic factors that contribute to Vibrio bacterial virulence and survival strategies within their ecological niche is of utmost importance for the effective prevention and management of diseases in aquaculture practices.


Assuntos
Arcidae , Sistemas de Secreção Tipo VI , Vibrio parahaemolyticus , Animais , Humanos , Virulência/genética , Fatores de Virulência/genética , Antibacterianos
7.
Environ Res ; 246: 118119, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38191038

RESUMO

In this study, a precipitation-based synthesis method has been employed to prepare magnesium calcites with the general formula Ca1-xMgxCO3, with the objective of use them in the calcium looping (CaL) process for CO2 capture (CaL-CCS) and thermochemical energy storage (CaL-CSP). The structure and microstructure of the samples have been characterized. It has been found by X-ray diffraction that the samples with a Ca:Mg molar ratio of 0.5:0.5 and 0.55:0.45 are phase pure, while the samples with molar ratios of 0.7:0.3 and 0.8:0.2 are composed by two phases with different stoichiometry. In addition, the sample prepared with calcium alone shows the aragonite phase. The microstructure of the magnesium-containing samples is composed of nanocrystals, which are aggregated in spherical particles whereas the aragonite sample presents a typical rod-like morphology. The multicycle tests carried out under CaL-CCS conditions show that an increase on the MgO content in the calcined samples results in a reduced value of effective conversion when compared to aragonite. On the other hand, under CaL-CSP conditions, the samples with the higher MgO content exhibit nearly stable effective conversion values around 0.5 after 20 cycles, which improve the results obtained for aragonite and those reported for natural dolomite tested under the same conditions.


Assuntos
Cálcio , Magnésio , Cálcio/química , Magnésio/química , Dióxido de Carbono/química , Óxido de Magnésio , Carbonato de Cálcio/química
8.
Microbiol Spectr ; 12(1): e0363522, 2024 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-38051056

RESUMO

IMPORTANCE: Influenza virus infection affects both lung and intestinal bacterial community composition. Most of the published analyses focus on the characterization of the microbiota composition changes. Here we assess functional alterations of gut microbiota such as nutrient and antibiotic resistance changes during an acute respiratory tract infection. Upon influenza A virus (IAV) infection, cecal microbiota drops accompanied by a decrease in the ability to metabolize some common nutrients under aerobic conditions. At the same time, the cecal community presents an increase in resistance against clinically relevant antibiotics, particularly cephalosporins. Functional characterization of complex communities presents an additional and necessary element of analysis that nowadays is mainly limited to taxonomic description. The consequences of these functional alterations could affect treatment strategies, especially in multimicrobial infections.


Assuntos
Microbioma Gastrointestinal , Vírus da Influenza A , Influenza Humana , Infecções por Orthomyxoviridae , Humanos , Influenza Humana/tratamento farmacológico , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico
9.
J Am Acad Dermatol ; 90(1): 66-73, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37704106

RESUMO

BACKGROUND: Evidence regarding long-term therapeutic outcomes and disease-specific survival (DSS) in Extramammary Paget's disease (EMPD) is limited. OBJECTIVES: To assess the DSS and outcomes of surgical and nonsurgical therapeutic modalities in a large cohort of EMPD patients. METHODS: Retrospective chart review of EMPD patients from 20 Spanish tertiary care hospitals. RESULTS: Data on 249 patients with a median follow-up of 60 months were analyzed. The estimated 5-, 10-, and 15-year DSS was 95.9%, 92.9%, and 88.5%, respectively. A significantly lower DSS was observed in patients showing deep dermal invasion (≥1 mm) or metastatic disease (P < .05). A ≥50% reduction in EMPD lesion size was achieved in 100% and 75.3% of patients treated with surgery and topical therapies, respectively. Tumor-free resection margins were obtained in 42.4% of the patients after wide local excision (WLE). The 5-year recurrence-free survival after Mohs micrographic surgery (MMS), WLE with tumor-free margins, WLE with positive margins, radiotherapy, and topical treatments was 63.0%, 51.4%, 20.4%, 30.1%, and 20.8%, respectively. LIMITATIONS: Retrospective design. CONCLUSIONS: EMPD is usually a chronic condition with favorable prognosis. MMS represents the therapeutic alternative with the greatest efficacy for the disease. Recurrence rates in patients with positive margins after WLE are similar to the ones observed in patients treated with topical agents.


Assuntos
Doença de Paget Extramamária , Humanos , Estudos Retrospectivos , Doença de Paget Extramamária/cirurgia , Cirurgia de Mohs , Análise de Sobrevida , Margens de Excisão , Resultado do Tratamento , Recidiva Local de Neoplasia/epidemiologia , Recidiva Local de Neoplasia/terapia , Recidiva Local de Neoplasia/patologia
10.
Energy Fuels ; 37(21): 16904-16914, 2023 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-37937311

RESUMO

Long-term storage capability is often claimed as one of the distinct advantages of the calcium looping process as a potential thermochemical energy storage system for integration into solar power plants. However, the influence of storage conditions on the looping performance has seldom been evaluated experimentally. The storage conditions must be carefully considered as any potential carbonation at the CaO storage tank would reduce the energy released during the subsequent carbonation, thereby penalizing the round-trip efficiency. From lab-scale to conceptual process engineering, this work considers the effects of storing solids at low temperatures (50-200 °C) in a CO2 atmosphere or at high temperatures (800 °C) in N2. Experimental results show that carbonation at temperatures below 200 °C is limited; thus, the solids could be stored during long times even in CO2. It is also demonstrated at the lab scale that the multicycle performance is not substantially altered by storing the solids at low temperatures (under CO2) or high temperatures (N2 atmosphere). From an overall process perspective, keeping solids at high temperatures leads to easier heat integration, a better plant efficiency (+2-4%), and a significantly higher energy density (+40-62%) than considering low-temperature storage. The smooth difference in the overall plant efficiency with the temperature suggests a proper long-term energy storage performance if adequate energy integration is carried out.

12.
Behav Sci (Basel) ; 13(10)2023 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-37887443

RESUMO

The construct of support needs has become a key aspect for the diagnostics, classification, and interventional management of autism spectrum disorders (ASDs). However, instruments specifically designed to assess support needs in this population are not available. Currently, the Supports Intensity Scale for Children (SIS-C), which could be administered to assess students with any type of intellectual disability (ID), is the only valid tool able to assess support needs in Spain. Our aim was to verify whether the SIS-C is useful for assessing the support needs of students with ASD, regardless of whether or not they present ID. The participants were subdivided into two groups. One group included students with ASD and ID (n = 248), and the other comprised participants with ASD without an ID (n = 44). The results of the two groups were compared with those reported in the original validation sample of the SIS-C, which involved participants with ID without ASD (n = 566). The results showed that this scale could be useful for assessing support needs in the three subgroups, but it appeared that different standardized norms based on the characteristics of each specific population would be appropriate.

13.
Life (Basel) ; 13(10)2023 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-37895399

RESUMO

There are various pathologies that involve the hallux, among which hallux valgus is the most common. When conservative treatment fails, it is necessary to resort to a surgical approach. The fixation elements for osteotomies in the hallux are usually composed of metallic materials; however, today, there are numerous resorbable materials that offer numerous advantages over conventional materials. In this article, the objective is to analyze the scientific evidence through the systematic analysis of the existing literature in relation to the effectiveness of resorbable versus non-resorbable osteosynthesis material in the surgical correction of hallux deformities and compare the complications as well as the patient satisfaction and quality of life between both fixation methods. A systematic review of the literature available in the PubMed, EMBASE, Web of Science and Scopus databases and 10 studies were included. The documents were chosen following the eligibility and exclusion criteria, including experimental and observational studies evaluated with the Jadad and Newcastle-Ottawa methodological quality scale, respectively. Data were extracted from valid studies for the review, and the variables functionality, pain, angular corrections, complications, satisfaction and quality of life were observed. In conclusion, there is limited scientific evidence regarding the effectiveness of resorbable versus non-resorbable osteosynthesis material in the surgical correction of hallux deformities. All observed variables are similar regardless of the surgical technique and osteosynthesis material used.

14.
Rev. Fac. Med. Hum ; 23(4): 186-192, oct.-dic. 2023. tab, graf
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1559090

RESUMO

RESUMEN La estrongiloidiasis comúnmente produce problemas gastrointestinales. Presentamos el caso de un varón, cadete en la marina de guerra del Perú, de 30 años, procedente de lima; que desarrolló síndrome de hiperinfección por Strongyloides Stercoralis, teniendo como antecedente el diagnóstico presuntivo de polimiositis, por lo cual recibió un ciclo corto de corticoesteroides. No portador del virus htlv 1/2. Presentó al ingreso hiporexia, debilidad generalizada, caquexia, diarrea intermitente autolimitada, intolerancia oral y leve distensión abdominal. El paciente llegó a la etapa de diseminación, lo que resultó en un daño severo a nivel intestinal. La baja excreción de larvas en las heces dificultó el diagnóstico. Se brindó tratamiento con ivermectina parenteral a dosis de 1.2ml vía subcutánea cada 48 horas por tres dosis, con buena respuesta clínica y posteriormente con buena tolerancia oral. La importancia de presentar el caso es comentar sobre el abordaje diagnóstico y terapéutico de esta geohelmintiasis endémica del Perú.


Abstract Strongyloidiasis commonly causes gastrointestinal problems. We present the case of a male, a 30-year-old cadet in the peruvian navy from lima, who developed a hyperinfection syndrome due to strongyloides stercoralis, having a presumptive diagnosis of polymyositis for which he received a short cycle of corticosteroids. He was not a carrier of the htlv 1/2 virus. Upon admission, he presented with hyporexia, generalized weakness, cachexia, intermittent self-limited diarrhea, oral intolerance, and mild abdominal distension. The patient reached the dissemination stage, resulting in severe intestinal damage. The low excretion of larvae in the feces made the diagnosis difficult. Treatment was provided with parenteral ivermectin at a dose of 1.2ml subcutaneously every 48 hours for three doses, with a good clinical response and subsequently good oral tolerance. The importance of presenting the case is to comment on the diagnostic and therapeutic approach to this endemic geohelminthiasis of peru.

15.
J Cutan Pathol ; 50(11): 983-990, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37605438

RESUMO

BACKGROUND: Pancreatic panniculitis is a rare form of panniculitis generally associated with acute or chronic pancreatitis, and less frequently with pancreatic carcinoma. Clinically, it presents with subcutaneous nodules usually located in the lower extremities, however, it presents an almost pathognomonic histopathological finding with enzymatic fat necrosis in the adipose tissue. METHODS: In this retrospective case series of five hospitals, biopsy specimens of cutaneous lesions of pancreatic panniculitis were reviewed. Clinical information was obtained through medical records. RESULTS: A total of 34 cases were included, 23 women and 11 men, aged between 31 and 92 years. The most common associated pancreatic disease was acute pancreatitis (23 cases) and its main triggering cause was gallstones (17 cases). In two patients it was related to chronic pancreatitis and six cases were associated with malignancy. Histopathological findings were always the key to diagnosis. In the biopsies reviewed, mostly lobular panniculitis with the characteristic necrosis of the adipocytes was observed. In addition, nine of the cases presented with Splendore-Hoeppli phenomenon. CONCLUSIONS: We present the largest series of pancreatic panniculitis. Clinically, the female predominance and biliary lithiasis as the main cause of acute pancreatitis are to be emphasized. Histopathologically, a peripheral eosinophilic striated rim surrounding aggregates of ghost adipocytes consistent with Splendore-Hoeppli is an additional clue to its diagnosis.

18.
Materials (Basel) ; 16(5)2023 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-36902967

RESUMO

Kinetic analysis remains a powerful tool for studying a large variety of reactions, which lies at the core of material science and industry. It aims at obtaining the kinetic parameters and model that best describe a given process and using that information to make reliable predictions in a wide range of conditions. Nonetheless, kinetic analysis often relies on mathematical models derived assuming ideal conditions that are not necessarily met in real processes. The existence of nonideal conditions causes large modifications to the functional form of kinetic models. Therefore, in many cases, experimental data hardly obey any of these ideal models. In this work, we present a novel method for the analysis of integral data obtained under isothermal conditions without any type of assumption about the kinetic model. The method is valid both for processes that follow and for those that do not follow ideal kinetic models. It consists of using a general kinetic equation to find the functional form of the kinetic model via numerical integration and optimization. The procedure has been tested both with simulated data affected by nonuniform particle size and experimental data corresponding to the pyrolysis of ethylene-propylene-diene.

19.
Clin. transl. oncol. (Print) ; 25(3): 768-775, mar. 2023.
Artigo em Inglês | IBECS | ID: ibc-216435

RESUMO

Background The Spanish Melanoma Group (GEM) developed a national registry of patients with melanoma infected by SARS-CoV-2 (“GRAVID”). Methods The main objective was to describe the COVID-19 fatality rate in patients with melanoma throughout the pandemic, as well as to explore the effect of melanoma treatment and tumor stage on the risk of COVID-19 complications. These are the final data of the register, including cases from February 2020 to September 2021. Results One hundred-fifty cases were registered. Median age was 68 years (range 6–95), 61 (40%) patients were females, and 63 (42%) patients had stage IV. Thirty-nine (26%) were on treatment with immunotherapy, and 17 (11%) with BRAF-MEK inhibitors. COVID-19 was resolved in 119 cases, including 85 (57%) patients cured, 15 (10%) that died due to melanoma, and 20 (13%) that died due to COVID-19. Only age over 60 years, cardiovascular disorders, and diabetes mellitus increased the risk of death due to COVID-19, but not advanced melanoma stage nor melanoma systemic therapies. Three waves have been covered by the register: February–May 2020, August–November 2020, and December 2020–April 2021. The first wave had the highest number of registered cases and COVID-19 mortality. Conclusion Tumor stage or melanoma treatments are non-significant prognostic factors for COVID-19 mortality. During the pandemic in Spain there was a downward trend in the number of patients registered across the waves, as well as in the severity of the infection (AU)


Assuntos
Humanos , Masculino , Feminino , Criança , Adolescente , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Infecções por Coronavirus/mortalidade , Pandemias , Melanoma/mortalidade , Neoplasias Cutâneas/mortalidade , Índice de Gravidade de Doença , Espanha/epidemiologia
20.
Materials (Basel) ; 16(3)2023 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-36770025

RESUMO

LaFeO3 perovskite ceramics have been prepared via reaction flash technique using Fe2O3 and La2O3 as precursors. The obtained pellets have been investigated using several techniques. The formation of LaFeO3 has been clearly confirmed by X-ray diffraction. The scanning electron microscopy micrographs have shown the microporous character of the obtained pellets due to the low temperature and dwell time used in the synthesis process (10 min at 1173 K). The orthorhombic-rhombohedral phase transition has been observed at approximately 1273 K in differential thermal analysis measurements, which also allows us to determine the Néel temperature at 742 K. The fitted Mössbauer spectra exposed the presence of a single sextet ascribed to the Fe+3 ions in the tetrahedral site. Finally, magnetic measurements at room temperature indicate the antiferromagnetic character of the sample.

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