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The Mi-1.2 gene confers resistance to a wide range of Meloidogyne species, being the most important resistance factor employed in tomato breeding so far. However, many aspects related to the interaction of Mi-1.2-carrying tomato cultivars and virulent/avirulent Meloidogyne populations have not yet been clarified. Herein, comparative histopathological analyses were carried after inoculation of the homozygous (Mi-1.2/Mi-1.2) tomato rootstock 'Guardião' and the susceptible cultivar 'Santa Clara' (mi-1.2/mi-1.2) with virulent and avirulent populations of M. javanica. In the susceptible control, it was possible to visualize second stage juveniles (J2) of avirulent population and feeding sites from 2 to 30 days after infection (DAI) with females reaching maturity at 24-34 DAI. In the resistant rootstock, the Mi-1.2 gene-mediated resistance was related mainly to early defense responses (pre-infection and hypersensitive reaction), which led to an immunity-like phenotype that completely prevented the reproduction of the avirulent Meloidogyne population. On the other hand, J2s of the virulent M. javanica population were able to penetrate roots much more than the avirulent population, migrated and developed normally, showing intense and similar pattern of penetration from 4 to 34 DAI in the root tissues of both resistant and susceptible tomato genotypes. The total numbers of J2, J3, J4, and females counted in 'Santa Clara' for the virulent population of M. javanica were higher than in 'Guardião'.
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BACKGROUND: Understanding the evolution of morphological features and their relationship with physical performance may assist coaches and institutions in developing the next generation of beach volleyball (BV) athletes for senior-level competition. Thus, this study analyzed the morphological features of Brazilian BV athletes by sex among age groups, and their relationship with physical performance. METHODS: A cross-sectional design was used to evaluate Brazilian BV players of both sexes in the U15 (11-14 years old, N.=21), U18 (15-17 years old, N.=21) and Senior (≥18 years old, N.=19) categories. The players underwent a series of kinanthropometric tests, including morphological (anthropometry, body composition and somatotype), neuromuscular (flexibility, handgrip strength, vertical jump [VJ], agility, and 5-m and 10-m maximum-speed sprints), and metabolic (VO
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Rendimiento Atlético , Voleibol , Humanos , Estudios Transversales , Voleibol/fisiología , Adolescente , Femenino , Masculino , Brasil , Rendimiento Atlético/fisiología , Factores Sexuales , Niño , Factores de Edad , Composición Corporal/fisiología , Somatotipos/fisiología , Antropometría , Fuerza de la Mano/fisiología , Adulto Joven , Músculo Esquelético/fisiología , Músculo Esquelético/anatomía & histologíaRESUMEN
PURPOSE: To evaluate color change in ceramic veneers luted to enamel with light-cured, dual-cured resin luting agents, or heated resin composites, as well as to evaluate microhardness and diametral tensile strength of these luting agents. METHODS: For color analysis, 0.5 mm-thick leucite-reinforced glass ceramic veneers (IPS Empress CAD) were cemented onto 40 bovine dental blocks (n= 10) using RelyX Ultimate (RU) or RelyX Veneer (RV) resin-based luting agents, or Gradia Direct (GD) and Palfique Lx5 (P) heated resin composites. After luting, the specimens were subjected to thermocycling (10,000 cycles). Color analysis was performed before and after thermocycling (L*, a*, b*, ΔEab, ΔE00). For the microhardness (Knoop) and diametral tensile strength tests, specimens (Ø 6 x 2 mm) were made (RU, RV, GD, and P). The specimens were subdivided into eight groups (n=10) and light-cured through different ceramic sheets (thicknesses of 0.5 mm or 1.5 mm). Knoop microhardness was performed on the top surface in a microhardness tester, and diametral tensile strength on a universal testing machine. Data were submitted to statistical analysis, using two-way ANOVA, Tukey, and Kruskal-Wallis tests (α= 0.05). RESULTS: For the general color alteration, there was no statistically significant difference between the luting materials (ΔEab, P= 0.57; ΔE00, P= 0.50). There was no interaction between luting agent and thermocycling, for L* (P= 0.87), a* (P= 0.97) and b* (P= 0.95) values. Thermocycling significantly affected only the L* values (P= 0.047), which increased after the cycles. For microhardness, there was a statistically significant difference considering luting agents and ceramic thickness (P< 0.001). GD heated resin composite presented significantly lower microhardness values than all other materials, at both ceramic thicknesses. At a thickness of 1.5 mm, RU cement had higher microhardness values than RV and P materials. Diametral tensile strength was significantly influenced by luting agent (P= 0.01), but not by ceramic thickness (P= 0.55). Diametral tensile strength of GD resin composite was higher than that of the RU, but neither of these two materials differed from RV and P. CLINICAL SIGNIFICANCE: Heated resin composite, used as luting agents, showed similar color stability to light-cured and dual-cure resin cements, however its microhardness was affected by ceramic thickness.
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Color , Resinas Compuestas , Coronas con Frente Estético , Dureza , Resistencia a la Tracción , Resinas Compuestas/química , Bovinos , Ensayo de Materiales , Animales , Cerámica/química , Calor , Cementos de Resina/química , Porcelana Dental/química , Análisis del Estrés DentalRESUMEN
Background and Objectives: Colon cancer (CC) is prevalent globally, constituting 11.9% of cases in Mexico. Lymph node metastases are established prognostic indicators, with extracapsular lymph node extension (ENE) playing a crucial role in modifying prognosis. While ENE is associated with adverse factors, certain aspects, like matted nodes (lymph node conglomerates), are underexplored. Matted nodes, clusters of lymph nodes infiltrated by cancer cells, are recognized as an independent prognostic factor in other cancers. This study investigates the prognostic implications of matted nodes in CC. Materials and Methods: From a retrospective analysis of 502 CC consecutive cases treated with colectomy (2005-2018), we identified 255 (50.8%) cases with lymph node metastasis (our study group), which were categorized into two groups: (1) lymph node metastasis alone (n = 208), and (2) lymph node metastasis with matted nodes (n = 47). A comparative survival analysis was performed. Results: Of the 255 patients, 38% had lymph node metastasis. Patients with matted nodes (18.4%) showed an association with higher pN stage and lymphovascular invasion. The 5-year survival rate for patients with matted nodes was 47.7%, compared to 60% without (p = 0.096); however, this association demonstrated only a statistical tendency. Multivariate analysis identified clinical stage and adjuvant chemotherapy use as independent factors contributing to survival. Conclusions: This study underscores matted nodes as potential prognostic indicators in CC, emphasizing their association with higher pN stage and reduced survival. Although the patients with matted nodes showed lower survival, this figure did not search statistical significance, but a tendency was detected, which necessitates precise further research, which is essential for validating these findings and integrating matted nodes into the broader context of colorectal cancer management.
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Adenocarcinoma , Neoplasias del Colon , Metástasis Linfática , Humanos , Masculino , Femenino , Estudios Retrospectivos , Neoplasias del Colon/mortalidad , Neoplasias del Colon/patología , Persona de Mediana Edad , Adenocarcinoma/mortalidad , Adenocarcinoma/patología , Anciano , Ganglios Linfáticos/patología , México/epidemiología , Pronóstico , Análisis de Supervivencia , Adulto , Colectomía/estadística & datos numéricos , Colectomía/métodos , Anciano de 80 o más Años , Estadificación de NeoplasiasRESUMEN
Background: Long COVID is an emerging global public health issue. Socially vulnerable communities in low- and-middle-income countries were severely impacted by the pandemic and are underrepresented in research. This prospective study aimed to determine the prevalence of long COVID, its impact on health, and associated risk factors in one such community in Rio de Janeiro, Brazil. Methods: A total of 710 individuals aged 18 and older, with confirmed SARS-CoV-2 infection at least three months prior, were enrolled between November 25, 2021, and May 5, 2022. Participants were assessed via telephone or in person using a standardized questionnaire to evaluate their perception of recovery, symptoms, quality of life, and functional status. Findings: Twenty percent of participants did not feel fully recovered, 22% experienced new or persistent symptoms, 26% had worsened functional status, 18% had increased dyspnoea, and 32% reported a worse quality of life. Persistent symptoms included headache, cough, fatigue, muscle pain, and shortness of breath. Dyspnoea during the acute phase was the strongest independent predictor of worsening outcomes. Females and individuals with comorbidities were more likely to report worse recovery, functioning, dyspnoea, and quality of life. Interpretation: Our findings reveal a high burden of severe and persistent physical and mental health sequelae in a socially vulnerable community following COVID-19. Funding: UK Foreign, Commonwealth and Development Office and Wellcome Trust Grant (222048/Z/20/Z), Fundação Oswaldo Cruz (FIOCRUZ), Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), and the Centers for Disease Control and Prevention (CDC).
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PURPOSE: Parametric regression models have been the main statistical method for identifying average treatment effects. Causal machine learning models showed promising results in estimating heterogeneous treatment effects in causal inference. Here we aimed to compare the application of causal random forest (CRF) and linear regression modelling (LRM) to estimate the effects of organisational factors on ICU efficiency. METHODS: A retrospective analysis of 277,459 patients admitted to 128 Brazilian and Uruguayan ICUs over three years. ICU efficiency was assessed using the average standardised efficiency ratio (ASER), measured as the average of the standardised mortality ratio (SMR) and the standardised resource use (SRU) according to the SAPS-3 score. Using a causal inference framework, we estimated and compared the conditional average treatment effect (CATE) of seven common structural and organisational factors on ICU efficiency using LRM with interaction terms and CRF. RESULTS: The hospital mortality was 14 %; median ICU and hospital lengths of stay were 2 and 7 days, respectively. Overall median SMR was 0.97 [IQR: 0.76,1.21], median SRU was 1.06 [IQR: 0.79,1.30] and median ASER was 0.99 [IQR: 0.82,1.21]. Both CRF and LRM showed that the average number of nurses per ten beds was independently associated with ICU efficiency (CATE [95 %CI]: -0.13 [-0.24, -0.01] and -0.09 [-0.17,-0.01], respectively). Finally, CRF identified some specific ICUs with a significant CATE in exposures that did not present a significant average effect. CONCLUSION: In general, both methods were comparable to identify organisational factors significantly associated with CATE on ICU efficiency. CRF however identified specific ICUs with significant effects, even when the average effect was nonsignificant. This can assist healthcare managers in further in-dept evaluation of process interventions to improve ICU efficiency.
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Mortalidad Hospitalaria , Unidades de Cuidados Intensivos , Humanos , Unidades de Cuidados Intensivos/organización & administración , Estudios Retrospectivos , Modelos Lineales , Femenino , Masculino , Brasil , Tiempo de Internación/estadística & datos numéricos , Eficiencia Organizacional , Persona de Mediana Edad , Aprendizaje Automático , Uruguay , Anciano , Adulto , Bosques AleatoriosRESUMEN
OBJECTIVES: No consensus exists about the best COVID-19 vaccination strategy to be adopted by low-income and middle-income countries. Brazil adopted an age-based calendar strategy to reduce mortality and the burden on the healthcare system. This study evaluates the impact of the vaccination campaign in Brazil on the progression of the reported COVID-19 deaths. METHODS: This ecological study analyses the dynamic of vaccination coverage and COVID-19 deaths in hospitalised adults (≥20 years) during the first year of the COVID-19 vaccination roll-out (January to December 2021) using nationwide data (DATASUS). We stratified the adult population into 20-49, 50-59, 60-69 and 70+ years. The dynamic effect of the vaccination campaign on mortality rates was estimated by applying a negative binomial regression. The prevented and possible preventable deaths (observed deaths higher than expected) and potential years of life lost (PYLL) for each age group were obtained in a counterfactual analysis. RESULTS: During the first year of COVID-19 vaccination, 266 153 517 doses were administered, achieving 91% first-dose coverage. A total of 380 594 deaths were reported, 154 091 (40%) in 70+ years and 136 804 (36%) from 50-59 or 20-49 years. The mortality rates of 70+ decreased by 52% (rate ratio [95% CI]: 0.48 [0.43-0.53]) in 6 months, whereas rates for 20-49 were still increasing due to low coverage (52%). The vaccination roll-out strategy prevented 59 618 deaths, 53 088 (89%) from those aged 70+ years. However, the strategy did not prevent 54 797 deaths, 85% from those under 60 years, being 26 344 (45%) only in 20-49, corresponding to 1 589 271 PYLL, being 1 080 104 PYLL (68%) from those aged 20-49 years. CONCLUSION: The adopted aged-based calendar vaccination strategy initially reduced mortality in the oldest but did not prevent the deaths of the youngest as effectively as compared with the older age group. Countries with a high burden, limited vaccine supply and young populations should consider other factors beyond the age to prioritise who should be vaccinated first.
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Vacunas contra la COVID-19 , COVID-19 , SARS-CoV-2 , Humanos , Brasil/epidemiología , COVID-19/prevención & control , COVID-19/mortalidad , COVID-19/epidemiología , Persona de Mediana Edad , Anciano , Vacunas contra la COVID-19/administración & dosificación , Adulto , Masculino , Femenino , Adulto Joven , Cobertura de Vacunación/estadística & datos numéricos , Programas de Inmunización , Vacunación/estadística & datos numéricosRESUMEN
Spin transport theory of non-Hermitian quantum systems, where the non-Hermiticity led to a series of exotic phenomena when the system experiences dissipation to an environment is proposed. The goal is a better understanding of the spin diffusion in the one-dimensional non-Hermitian XXZ model which allows the transport coefficients be computed analytically. Moreover, we analyzed the electric transport in the one-dimensional non-Hermitian Hubbard model which is a very important model of electrons strongly correlated, where we have investigated the effect of non-Hermitian parameters like the imaginary hopping on AC and DC conductivities of the system. We analyzed the large U limit of this model, where such non-Hermiticity contributes with a minus sign in the virtual exchange of quasiparticles and the behavior of the ground state energy and low-lying excitations is reversed.
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A cloud point method was developed and applied for the first time to extract and preconcentrate thiabendazole (TBZ) from commercial whole grape juice samples, with determination by high performance liquid chromatography coupled to electrochemical detection (HPLC/EC), using a cathodically pretreated boron-doped diamond electrode (BDD). The best conditions for extraction and preconcentration of TBZ by cloud point extraction (CPE) were performed at pH 6.0, by adding 1 mL of the surfactant Tergitol TMN-6 at 10% (mass-to-mass ratio), without heating (at 27 °C) and ultrasonic stirring time of (20 kHz) for 60 min. The HPLC/EC determination was duly validated in a C8 column, in mobile phase with a 69 : 31 ratio (V/V) of phosphate buffer (pH 7.0):ACN, at a flow rate of 1.2 mL min-1 and electrochemical detection with BDD electrode by applying 1.40 V × Ag/AgCl (3.0 mol L-1). Under these conditions, the procedure showed a preconcentration factor (FC) of 21.7, and limits of detection (LOD) and quantification (LOQ) of 6.64 × 10-9 mol L-1 (or 1.33 µg L-1) and 1.66 × 10-8 mol L-1 (or 3.34 µg L-1), respectively. The method provided a percent recovery of 81% to 98%, with a coefficient of variation between 3% and 15%.
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Técnicas Electroquímicas , Jugos de Frutas y Vegetales , Tiabendazol , Vitis , Cromatografía Líquida de Alta Presión/métodos , Tiabendazol/análisis , Tiabendazol/aislamiento & purificación , Jugos de Frutas y Vegetales/análisis , Vitis/química , Técnicas Electroquímicas/métodos , Límite de Detección , Electrodos , Plaguicidas/análisis , Contaminación de Alimentos/análisisRESUMEN
Chikungunya virus (CHIKV) has been reported in over 120 countries and is the causative agent of Chikungunya fever. The debilitating nature of this disease, which can persist months to years after acute infection, drastically impacts the quality of life of patients. Yet, specific antivirals are lacking for the treatment of this disease, which makes the search for new drugs necessary. In this context, the nsP2 protease emerges as an attractive therapeutic target, and drug repurposing strategies have proven to be valuable. Therefore, we combined in silico and in vitro methods to identify known drugs as potential CHIKV nsP2 protease inhibitors with antiviral properties within DrugBank. Herein, we developed a hybrid virtual screening pipeline comprising pharmacophore- and target-based screening, drug-like, and pharmaceutical filtering steps. Six virtual hits were obtained, and two of them, capecitabine (CPB) and oxibendazole (OBZ), were evaluated against CHIKV replication in Vero cells. CPB did not present antiviral activity, whereas OBZ inhibited the replication of two different strains of CHIKV, namely, 181-25 (Asian genotype) and BRA/RJ/18 (clinical isolate from ECSA genotype). OBZ showed potent antiviral activity against the CHIKV BRA/RJ/18 (EC50 = 11.4 µM) with a high selectivity index (>44). Analogs of OBZ (albendazole, fenbendazole, and mebendazole) were also evaluated, but none exhibited anti-CHIKV activity, and further, their stereoelectronic features were analyzed. Additionally, we observed that OBZ acts mainly at post-entry steps. Hence, our results support further in vivo studies to investigate the antiviral potential of OBZ, which offers a new alternative to fight CHIKV infections.
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In this editorial, we comment on the article by Wang et al. This manuscript explores the potential synergistic effects of combining zanubrutinib, a novel oral inhibitor of Bruton's tyrosine kinase, with high-dose methotrexate (HD-MTX) as a therapeutic intervention for primary central nervous system lymphoma (PCNSL). The study involves a retrospective analysis of 19 PCNSL patients, highlighting clinicopathological characteristics, treatment outcomes, and genomic biomarkers. The results indicate the combination's good tolerance and strong antitumor activity, with an 84.2% overall response rate. The authors emphasize the potential of zanubrutinib to modulate key genomic features of PCNSL, particularly mutations in myeloid differentiation primary response 88 and cluster of differentiation 79B. Furthermore, the study investigates the role of circulating tumor DNA in cerebrospinal fluid for disease surveillance and treatment response monitoring. In essence, the study provides valuable insights into the potential of combining zanubrutinib with HD-MTX as a frontline therapeutic regimen for PCNSL. The findings underscore the importance of exploring alternative treatment modalities and monitoring genomic and liquid biopsy markers to optimize patient outcomes. While the findings suggest promise, the study's limitations should be considered, and further research is needed to establish the clinical relevance of this therapeutic approach for PCNSL.
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The Neotropical region is the most diverse on the planet, largely owing to its mosaic of tropical rainforests. Multiple tectonic and climatic processes have been hypothesized to contribute to generating this diversity, including Andean orogeny, the closure of the Isthmus of Panama, the GAARlandia land bridge and historical connections among currently isolated forests. Micrathena spiders are diverse and widespread in the region, and thus a complete phylogeny of this genus allows the testing of hypotheses at multiple scales. We estimated a complete, dated phylogeny using morphological data for 117 Micrathena species and molecular data of up to five genes for a subset of 79 species. Employing event-based approaches and biogeographic stochastic mapping while considering phylogenetic uncertainty, we estimated ancestral distributions, the timing and direction of dispersal events and diversification rates among areas. The phylogeny is generally robust, with uncertainty in the position of some of the species lacking sequences. Micrathena started diversifying around 25 Ma. Andean cloud forests show the highest in-situ speciation, while the Amazon is the major dispersal source for adjacent areas. The Dry Diagonal generated few species and is a sink of diversity. Species exchange between Central and South America involved approximately 23 dispersal events and started ~20 Ma, which is consistent with a Miocene age for the Isthmus of Panama closure. We inferred four dispersal events from Central America to the Antilles in the last 20 Myr, indicating the spiders did not reach the islands through the GAARlandia land bridge. We identified important species exchange routes among the Amazon, Andean cloud forests and Atlantic forests during the Plio-Pleistocene. Sampling all species of the genus was fundamental to the conclusions above, especially in identifying the Andean forests as the area that generated the majority of species. This highlights the importance of complete taxonomic sampling in biogeographic studies.
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Especiación Genética , Filogenia , Bosque Lluvioso , Arañas , Animales , Arañas/genética , Arañas/clasificación , Arañas/fisiología , Islas , Distribución AnimalRESUMEN
We enrolled 21 patients with laboratory-confirmed yellow fever (YF), hospitalized at Eduardo de Menezes Hospital, Brazil, to be treated with sofosbuvir, a drug approved for hepatitis C. Given the absence of specific YF antiviral treatments, the off-label nonrandomized sofosbuvir treatment aimed to address high disease severity and the risk of fatal outcomes. Patients received a daily dose of 400â mg sofosbuvir from 4 to 10 days post-symptom onset. YF viral load (VL) comparisons were made between treated and nontreated patients who either survived or died. The genomic VL for the treated group steadily decreased after day 7 post-symptom onset, suggesting that sofosbuvir might reduce YF VL. This study underscores the urgent need for YF antiviral therapies, advocating for randomized clinical trials to further explore sofosbuvir's role in YF treatment.
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Parrot bornaviruses are responsible for proventricular dilatation disease (PDD) in psittacines. This study aimed to determine the occurrence and factors associated with Parrot bornaviruses infection in psittacines kept in captivity in a state in the southern region of Brazil. A cross-sectional study was carried out with 192 birds from two facilities (A and B) in 2019, using choanal, esophageal, and cloacal swabs and feathers, totaling 768 samples subjected to reverse-transcription polymerase chain reaction (RT-PCR), for the matrix (M) protein gene with a final product of 350 base pairs (bp). Genetic sequencing of three positive samples was performed by the Sanger method. In the study, the overall virus occurrence was 35.9% (69/192), with 40.4% (42/104) in Facility A and 30.7% (27/88) in Facility B. Sequencing analysis of the samples revealed the presence of Parrot bornavirus 2 (PaBV-2) in both facilities. Swab samples from the choanal (40/69), esophageal (30/69), cloacal (35/69), and feather (15/69) tested positive, facilitating the molecular diagnosis of Parrot bornaviruses. The results indicated that there is no single ideal sample type for antemortem molecular diagnosis of this virus. Simultaneously testing all four samples at the same time point yielded more diagnoses than testing any single sample among the four. Most of the 29 sampled psittacine species were native, and 46.9% of the birds (90/192) consisted of endangered species. Among the psittacines that tested positive, 88.4% (61/69) were clinically healthy, and 8.7% (6/69) exhibited clinical or behavioral signs, including behavioral changes, alterations in feathering, and changes in body score at the time of collection. This study showcases the application of minimally invasive sampling for diagnosing Parrot bornaviruses, enabling sample collection when the birds are restrained for clinical evaluation. This approach facilitates a prompt and effective antemortem diagnosis, thereby serving as an efficient screening method for parrots kept in captivity.
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Enfermedades de las Aves , Bornaviridae , Infecciones por Mononegavirales , Animales , Brasil/epidemiología , Enfermedades de las Aves/virología , Enfermedades de las Aves/epidemiología , Bornaviridae/aislamiento & purificación , Bornaviridae/genética , Bornaviridae/clasificación , Infecciones por Mononegavirales/veterinaria , Infecciones por Mononegavirales/virología , Infecciones por Mononegavirales/epidemiología , Estudios Transversales , Animales de Zoológico , Loros/virología , Psittaciformes/virologíaRESUMEN
INTRODUCTION: The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) posed a significant public health challenge globally, with Brazil being no exception. Excess mortality during this period reached alarming levels. Cardiovascular diseases (CVD), Systemic Hypertension (HTN), and Diabetes Mellitus (DM) were associated with increased mortality. However, the specific impact of DM and HTN on mortality during the pandemic remains poorly understood. METHODS: This study analyzed mortality data from Brazil's mortality system, covering the period from 2015 to 2022. Data included all causes of death as listed on death certificates, categorized by International Classification of Diseases 10th edition (ICD-10) codes. Population data were obtained from the Brazilian Census. Mortality ratios (MRs) were calculated by comparing death rates in 2020, 2021, and 2022 to the average rates from 2015 to 2019. Adjusted MRs were calculated using Poisson models. RESULTS: Between 2015 and 2022, Brazil recorded a total of 11,423,288 deaths. Death rates remained relatively stable until 2019 but experienced a sharp increase in 2020 and 2021. In 2022, although a decrease was observed, it did not return to pre-pandemic levels. This trend persisted even when analyzing records mentioning DM, HTN, or CVD. Excluding death certificates mentioning COVID-19 codes, the trends still showed increases from 2020 through 2022, though less pronounced. CONCLUSION: This study highlights the persistent high mortality rates for DM and HTN in Brazil during the years 2020-2022, even after excluding deaths associated with COVID-19. These findings emphasize the need for continued attention to managing and preventing DM and HTN as part of public health strategies, both during and beyond the COVID-19 pandemic. There are complex interactions between these conditions and the pandemic's impact on mortality rates.
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Cobalt(III) and chromium(III) salophen chloride complexes were synthesized and tested for the cycloaddition of carbon dioxide (CO2) with epoxides to obtain cyclic carbonates. The cat1, cat2, cat4, and cat5 complexes presented high catalytic activity without cocatalysts and are solvent-free at 100 °C, 8 bar, and 9 h. At these conditions, the terminal epoxides (1a-1k) were successfully converted into the corresponding cyclic carbonates with a maximum conversion of â¼99%. Moreover, cat5 was highlighted due to its capability of opening internal epoxides such as limonene oxide (1l) with a 36% conversion to limonene carbonate (2l), and from cyclohexene oxide (1m), cyclic trans-cyclohexene carbonate (2m) and poly(cyclohexene carbonate) were obtained with 15% and 85% selectivity, respectively. A study of the coupling reaction mechanism was proposed with the aid of electrospray ionization mass spectrometry (ESI-MS) analysis, confirming the single-component behavior of the complexes through their ionization due to epoxide coordination. In addition, crystallographic analysis of cat1 single crystals grown in a saturated solution of pyridine helped to demonstrate that the substitution of chloride ion by pyridine ligands to form an octahedral coordination occurs (Py-cat1), supporting the proposed mechanism. Also, a recyclability study was performed for cat5, and a total turnover number of 952 was obtained with only minor losses in catalytic activity after five cycles.
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This article describes the development of a nickel-catalyzed regio- and diastereoselective formal [3+2] cycloaddition between N-substituted indoles and donor-acceptor cyclopropanes to synthesize cyclopenta[b]indoles. Optimized reaction conditions provide the desired nitrogen-containing cycloadducts in up to 93% yield and dr 8.6:1 with complete regioselectivity. The substrate scope showed high tolerance to various substituted indoles and cyclopropanes, resulting in the synthesis of six new cyclopenta[b]indoles and the isolation of five derivatives previously reported in the literature. In addition, a mechanistic proposal for the reaction was studied through online reaction monitoring by ESI-MS, allowing for the identification of the reactive intermediates in the Ni(II) catalyzed process. X-ray crystallography confirmed the structure and relative endo stereochemistry of the products. This method enables the fast and efficient construction of fused indolines from readily accessible starting materials.
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The South American palpimanid genus Fernandezina Birabn currently comprises 15 described species, all known from epigean environments. Representatives of Fernandezina are easily recognized by the unexpanded femora I in both sexes and by the dorsally extended opisthosomal scutum in males. Herein, F. fernandoi sp. nov. is described based on males and females from hypogean environments and F. angeloi sp. nov. is described based on a single male from a nearby epigean environment, both in Brazil. Additionally, we provide an identification key for the species of the genus.