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7-Azaindole has been integrated as building block with complementary N-H···N hydrogen bonding sites for the synthesis of a tetrahedral molecular tecton, namely tetra(α-carbolin-6-yl)methane, TACM. The self-assembly of this molecule results in a 3D hydrogen-bonded organic framework (HOF). This supramolecular structure constitutes a crystalline microporous material with an extraordinary thermal and chemical robustness. Single crystal X-ray diffraction reveals how the five-fold catenation of diamonoid systems, stabilized by hydrogen bonds and π-π interactions, form an interpenetrated network with monodimensional channels. The structural features of the crystalline material are also observed by transmission electron microscopy (TEM). Additionally, the microporosity of the activated TACM-HOF is characterized by gas sorption (N2, CO2, CH4 and H2) experiments performed at different pressures. A selective adsorption is observed for CO2 uptake and TACM-HOF also presents a good adsorption capacity for H2 among supramolecular organic frameworks.
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The organic compound niacin or nicotinic acid, also known as vitamin B3 (VitB3), is essential for human nutrition and metabolic regulation. However, in high doses, it can provoke side effects, such as hyperglycemia, liver damage, and flushing. Development of a controlled release system that slowly releases VitB3 into the organism would avoid high dosing peaks, thus contributing to decrease the occurrence of side effects in nutritional supplementation. Here, we show that the slow and controlled release of VitB3 in an acid environment can be achieved via its intercalation in layered double hydroxides (LDHs). The synthesis of a ZnAl-VitB3 system is shown, in which VitB3 is intercalated in a ZnAl LDH. The presence of VitB3 in the ZnAl-VitB3 system was confirmed by elemental analysis, infrared (FTIR) and NMR spectroscopy, while successful intercalation in the LDHs was revealed by powder X-ray diffraction (PXRD). In vitro release tests were carried out in a concentrated HCl solution of pH 1.5, a pH similar to the human stomach environment. The results showed a steady release of VitB3 from the LDH host, with 90% of the vitamin liberated in the first 60 min after the suspension of the LDH in the acidic solution.
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BACKGROUND: This study was conducted to evaluate the cost-benefit indicators of a vancomycin monitoring protocol based on area under the curve estimation using commercial Bayesian software. METHODS: This quasi-experimental study included patients who were aged >18 years with a vancomycin prescription for >24 hours. Patients who were terminally ill or those with acute kidney injury (AKI) ≤24 hours were excluded. During the preintervention period, doses were adjusted based on the trough concentration target of 15-20 mg/L, whereas the postintervention period target was 400-500 mg × h/L for the area under the curve. The medical team was responsible for deciding to stop the antimicrobial prescription without influence from the therapeutic drug monitoring team. The main outcomes were the incidence of AKI and length of stay. Cost-benefit simulation was performed after statistical analysis. RESULTS: There were 96 patients in the preintervention group and 110 in the postintervention group. The AKI rate decreased from 20% (n = 19) to 6% (n = 6; P = 0.003), whereas the number of vancomycin serum samples decreased from 5 (interquartile range: 2-7) to 2 (interquartile range: 1-3) examinations per patient (P < 0.001). The mean length of hospital stay for patients was 26.19 days after vancomycin prescription, compared with 17.13 days for those without AKI (P = 0.003). At our institution, the decrease in AKI rate and reduced length of stay boosted yearly savings of up to US$ 369,000 for 300 patients receiving vancomycin therapy. CONCLUSIONS: Even in resource-limited settings, a commercial Bayesian forecasting-based protocol for vancomycin is important for determining cost-benefit outcomes.
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âââââââThe so-called arc of deforestation is a major agricultural and industrial frontier in southern Amazonia and northern Cerrado of Brazil. As arboreal mammals, the primates in this region are therefore threatened by forest loss and fragmentation. At the same time, knowledge about the taxonomic diversity and distribution ranges of these taxa is incomplete, which might hamper efficient conservation measurements. New species have been recently discovered in this region, and their ranges remain imprecise because only a few occurrence records are available for each species. Here we present 192 new records of 22 species and subspecies of Alouatta, Aotus, Ateles, Cebus, Chiropotes, Lagothrix, Leontocebus, Pithecia, Plecturocebus, Saimiri, and Sapajus, collected in 56 different localities during 10 field expeditions across the arc of deforestation between 2015 and 2018. Based on these new records, we extend the ranges of Alouatta puruensis, Ateles chamek, and Saimiri collinsi; identify potential hybridization zones between A. puruensis and A. discolor, and between At. chamek and At. marginatus; redefine the range of Plecturocebus moloch; and clarify the ranges of P. baptista and P. hoffmannsi. Moreover, these results and the dataset are valuable for further research on, for example, species distribution and habitat use modeling, for assessing species extinction risks, and for supporting efforts for the conservation of species increasingly threatened on a global deforestation frontier.
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INTRODUCTION: Soft skills represent a range of personal skills, attitudes and characteristics relevant to success and adequate work performance. OBJECTIVE: This study aimed to evaluate the knowledge and usage of soft skills in Orthodontics. METHODS: The participants answered a questionnaire containing 27 objective questions on awareness and frequency of soft skills in their professional activities. Participants were also asked to rank the soft skills in a crescent order of importance. The sample was divided into subgroups: A) residents in Orthodontics; B) orthodontists with less than 5 years of experience and C) orthodontists with more than 5 years of experience. Intergroup comparisons were performed using the Kruskal-Wallis test. Sexual differences were compared using Mann-Whitney test (p<â 0.05). RESULTS: The sample of this observational study comprised 129 experienced orthodontists and residents in Orthodontics (92 women, 37 men) with mean age of 35.3 years. From the total sample, 54,6% of respondents reported no previous instructions on soft skills. All respondents reported using the analyzed soft skills with a similar frequency (median 4-5). Residents reported accessing reliable sources in bibliographic research less frequently (46%). Female orthodontists reported to seek help from teachers and other professionals more often than males. Ethics and communication were frequently ranked as the most important soft skills. Information management and leadership were frequently less ranked as important soft skills. CONCLUSION: Poor knowledge of soft skills was demonstrated by residents and orthodontists. Communication skill was highly used and frequently ranked as the most important soft skill.
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Competência Clínica , Internato e Residência , Ortodontia , Ortodontistas , Humanos , Feminino , Masculino , Ortodontia/educação , Adulto , Inquéritos e QuestionáriosRESUMO
The functionalisation of organic linkers in metal-organic frameworks (MOFs) to improve gas uptake is well-documented. Although the positive role of free carboxylic acid sites in MOFs for binding gas molecules has been proposed in computational studies, relatively little experimental evidence has been reported in support of this. Primarily this is because of the inherent synthetic difficulty to prepare MOF materials bearing free, accessible -COOH moieties which would normally bind to metal ions within the framework structure. Here, we describe the direct binding of CO2 and C2H2 molecules to the free -COOH sites within the pores of MFM-303(Al). MFM-303(Al) exhibits highly selective adsorption of CO2 and C2H2 with a high selectivity for C2H2 over C2H4. In situ synchrotron X-ray diffraction and inelastic neutron scattering, coupled with modelling, highlight the cooperative interactions of adsorbed CO2 and C2H2 molecules with free -COOH and -OH sites within MFM-303(Al), thus rationalising the observed high selectivity for gas separation.
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Endolysins are bacteriophage (or phage)-encoded enzymes that catalyse the peptidoglycan breakdown in the bacterial cell wall. The exogenous action of recombinant phage endolysins against Gram-positive organisms has been extensively studied. However, the outer membrane acts as a physical barrier when considering the use of recombinant endolysins to combat Gram-negative bacteria. This study aimed to evaluate the antimicrobial activity of the SAR-endolysin LysKpV475 against Gram-negative bacteria as single or combined therapies, using an outer membrane permeabilizer (polymyxin B) and a phage, free or immobilized in a pullulan matrix. In the first step, the endolysin LysKpV475 in solution, alone and combined with polymyxin B, was tested in vitro and in vivo against ten Gram-negative bacteria, including highly virulent strains and multidrug-resistant isolates. In the second step, the lyophilized LysKpV475 endolysin was combined with the phage phSE-5 and investigated, free or immobilized in a pullulan matrix, against Salmonella enterica subsp. enterica serovar Typhimurium ATCC 13311. The bacteriostatic action of purified LysKpV475 varied between 8.125 µgâ¯ml-1 against Pseudomonas aeruginosa ATCC 27853, 16.25 µgâ¯ml-1 against S. enterica Typhimurium ATCC 13311, and 32.50 µgâ¯ml-1 against Klebsiella pneumoniae ATCC BAA-2146 and Enterobacter cloacae P2224. LysKpV475 showed bactericidal activity only for P. aeruginosa ATCC 27853 (32.50 µgâ¯ml-1) and P. aeruginosa P2307 (65.00 µgâ¯ml-1) at the tested concentrations. The effect of the LysKpV475 combined with polymyxin B increased against K. pneumoniae ATCC BAA-2146 [fractional inhibitory concentration index (FICI) 0.34; a value lower than 1.0 indicates an additive/combined effect] and S. enterica Typhimurium ATCC 13311 (FICI 0.93). A synergistic effect against S. enterica Typhimurium was also observed when the lyophilized LysKpV475 at â MIC was combined with the phage phSE-5 (m.o.i. of 100). The lyophilized LysKpV475 immobilized in a pullulan matrix maintained a significant Salmonella reduction of 2 logs after 6 h of treatment. These results demonstrate the potential of SAR-endolysins, alone or in combination with other treatments, in the free form or immobilized in solid matrices, which paves the way for their application in different areas, such as in biocontrol at the food processing stage, biosanitation of food contact surfaces and biopreservation of processed food in active food packing.
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Antibacterianos , Endopeptidases , Glucanos , Polimixina B , Fagos de Salmonella , Endopeptidases/farmacologia , Endopeptidases/química , Endopeptidases/metabolismo , Polimixina B/farmacologia , Antibacterianos/farmacologia , Antibacterianos/química , Fagos de Salmonella/genética , Fagos de Salmonella/fisiologia , Fagos de Salmonella/química , Glucanos/química , Glucanos/farmacologia , Animais , Testes de Sensibilidade Microbiana , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/virologia , Camundongos , Salmonella typhimurium/virologia , Salmonella typhimurium/efeitos dos fármacos , Bacteriófagos/fisiologia , Bacteriófagos/genética , Proteínas Virais/genética , Proteínas Virais/metabolismo , Proteínas Virais/farmacologia , Proteínas Virais/químicaRESUMO
Layered LnBaCo2O6-δ perovskites are important mixed ionic-electronic conductors, exhibiting outstanding catalytic properties for the oxygen evolution/reduction reaction. These phases exhibit considerable structural complexity, in particular, near room temperature, where a number of oxygen vacancy ordered superstructures are found. This study uses bond valence site energy calculations to demonstrate the key underlying structural features that favor facile ionic migration. BVSE calculations show that the 1D vacancy ordering for Ln = Sm-Tb could be beneficial at low temperatures as new pathways with reduced barriers emerge. By contrast, the 2D vacancy ordering for Ln = Dy and Y is not beneficial for ionic transport with the basic layered parent material having lower migration barriers. Overall, the key criterion for low migration barriers is an expanded ab plane, supported by Ba, coupled to a small Ln size. Hence, Ln = Y should be the best composition, but this is stymied by the low temperature 2D vacancy ordering and moderate temperature stability. The evolution of the oxygen cycling capability of these materials is also reported.
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Mitochondria provide energy for all cellular processes, including reactions associated with cell cycle progression, DNA damage repair, and cilia formation. Moreover, mitochondria participate in cell fate decisions between death and survival. Nek family members have already been implicated in DNA damage response, cilia formation, cell death, and cell cycle control. Here, we discuss the role of several Nek family members, namely Nek1, Nek4, Nek5, Nek6, and Nek10, which are not exclusively dedicated to cell cycle-related functions, in controlling mitochondrial functions. Specifically, we review the function of these Neks in mitochondrial respiration and dynamics, mtDNA maintenance, stress response, and cell death. Finally, we discuss the interplay of other cell cycle kinases in mitochondrial function and vice versa. Nek1, Nek5, and Nek6 are connected to the stress response, including ROS control, mtDNA repair, autophagy, and apoptosis. Nek4, in turn, seems to be related to mitochondrial dynamics, while Nek10 is involved with mitochondrial metabolism. Here, we propose that the participation of Neks in mitochondrial roles is a new functional axis for the Nek family.
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Mitocôndrias , Proteínas Serina-Treonina Quinases , Quinases Relacionadas a NIMA/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Mitocôndrias/metabolismo , Homeostase , DNA MitocondrialRESUMO
DEAD-box helicases are global regulators of liquid-liquid phase separation (LLPS), a process that assembles membraneless organelles inside cells. An outstanding member of the DEAD-box family is DDX3X, a multi-functional protein that plays critical roles in RNA metabolism, including RNA transcription, splicing, nucleocytoplasmic export, and translation. The diverse functions of DDX3X result from its ability to bind and remodel RNA in an ATP-dependent manner. This capacity enables the protein to act as an RNA chaperone and an RNA helicase, regulating ribonucleoprotein complex assembly. DDX3X and its orthologs from mouse, yeast (Ded1), and C. elegans (LAF-1) can undergo LLPS, driving the formation of neuronal granules, stress granules, processing bodies or P-granules. DDX3X has been related to several human conditions, including neurodevelopmental disorders, such as intellectual disability and autism spectrum disorder. Although the research into the pathogenesis of aberrant biomolecular condensation in neurodegenerative diseases is increasing rapidly, the role of LLPS in neurodevelopmental disorders is underexplored. This review summarizes current findings relevant for DDX3X phase separation in neurodevelopment and examines how disturbances in the LLPS process can be related to neurodevelopmental disorders.
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Transtorno do Espectro Autista , RNA Helicases DEAD-box , Transtornos do Neurodesenvolvimento , Animais , Humanos , Camundongos , Transtorno do Espectro Autista/genética , Caenorhabditis elegans/metabolismo , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/metabolismo , Transtornos do Neurodesenvolvimento/genética , RNA/metabolismo , Saccharomyces cerevisiae/metabolismoRESUMO
The selective capture of methane (CH4) at low concentrations and its separation from N2 are extremely challenging owing to the weak host-guest interactions between CH4 molecules and any sorbent material. Here, we report the exceptional adsorption of CH4 at low pressure and the efficient separation of CH4/N2 by MFM-300(Fe). MFM-300(Fe) shows a very high uptake for CH4 of 0.85â mmol g-1 at 1â mbar and 298â K and a record CH4/N2 selectivity of 45 for porous solids, representing a new benchmark for CH4 capture and CH4/N2 separation. The excellent separation of CH4/N2 by MFM-300(Fe) has been confirmed by dynamic breakthrough experiments. Inâ situ neutron powder diffraction, and solid-state nuclear magnetic resonance and diffuse reflectance infrared Fourier transform spectroscopies, coupled with modelling, reveal a unique and strong binding of CH4 molecules involving Fe-OHâ¯CH4 and Câ¯phenyl ring interactions within the pores of MFM-300(Fe), thus promoting the exceptional adsorption of CH4 at low pressure.
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PURPOSE: The goal of this study was to investigate severe central nervous system infections (CNSI) in adults admitted to the intensive care unit (ICU). We analyzed the clinical presentation, causes, and outcomes of these infections, while also identifying factors linked to higher in-hospital mortality rates. MATERIALS AND METHODS: We conducted a retrospective multicenter study in Rio de Janeiro, Brazil, from 2012 to 2019. Using a prediction tool, we selected ICU patients suspected of having CNSI and reviewed their medical records. Multivariate analyses identified variables associated with in-hospital mortality. RESULTS: In a cohort of 451 CNSI patients, 69 (15.3%) died after a median 11-day hospitalization (5-25 IQR). The distribution of cases was as follows: 29 (6.4%) had brain abscess, 161 (35.7%) had encephalitis, and 261 (57.8%) had meningitis. Characteristics: median age 41 years (27-53 IQR), 260 (58%) male, and 77 (17%) HIV positive. The independent mortality predictors for encephalitis were AIDS (OR = 4.3, p = 0.01), ECOG functional capacity limitation (OR = 4.0, p < 0.01), ICU admission from ward (OR = 4.0, p < 0.01), mechanical ventilation ≥10 days (OR = 6.1, p = 0.04), SAPS 3 ≥ 55 points (OR = 3.2, p = 0.02). Meningitis: Age > 60 years (OR = 234.2, p = 0.04), delay >3 days for treatment (OR = 2.9, p = 0.04), mechanical ventilation ≥10 days (OR = 254.3, p = 0.04), SOFA >3 points (OR = 2.7, p = 0.03). Brain abscess: No associated factors found in multivariate regression. CONCLUSIONS: Patients' overall health, prompt treatment, infection severity, and prolonged respiratory support in the ICU all significantly affect in-hospital mortality rates. Additionally, the implementation of CNSI surveillance with the used prediction tool could enhance public health policies.
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Abscesso Encefálico , Infecções do Sistema Nervoso Central , Encefalite , Meningite , Adulto , Humanos , Masculino , Pessoa de Meia-Idade , Feminino , Estudos Retrospectivos , Brasil/epidemiologia , Cuidados Críticos , Unidades de Terapia Intensiva , Mortalidade Hospitalar , Infecções do Sistema Nervoso Central/epidemiologia , Meningite/epidemiologiaRESUMO
ABSTRACT Introduction: Soft skills represent a range of personal skills, attitudes and characteristics relevant to success and adequate work performance. Objective: This study aimed to evaluate the knowledge and usage of soft skills in Orthodontics. Methods: The participants answered a questionnaire containing 27 objective questions on awareness and frequency of soft skills in their professional activities. Participants were also asked to rank the soft skills in a crescent order of importance. The sample was divided into subgroups: A) residents in Orthodontics; B) orthodontists with less than 5 years of experience and C) orthodontists with more than 5 years of experience. Intergroup comparisons were performed using the Kruskal-Wallis test. Sexual differences were compared using Mann-Whitney test (p<0.05). Results: The sample of this observational study comprised 129 experienced orthodontists and residents in Orthodontics (92 women, 37 men) with mean age of 35.3 years. From the total sample, 54,6% of respondents reported no previous instructions on soft skills. All respondents reported using the analyzed soft skills with a similar frequency (median 4-5). Residents reported accessing reliable sources in bibliographic research less frequently (46%). Female orthodontists reported to seek help from teachers and other professionals more often than males. Ethics and communication were frequently ranked as the most important soft skills. Information management and leadership were frequently less ranked as important soft skills. Conclusion: Poor knowledge of soft skills was demonstrated by residents and orthodontists. Communication skill was highly used and frequently ranked as the most important soft skill.
RESUMO Introdução: As soft skills representam uma variedade de habilidades pessoais, atitudes e características relevantes para o sucesso e desempenho adequado no trabalho. Objetivo: Este estudo teve como objetivo avaliar o conhecimento e o uso das soft skills em ortodontistas. Métodos: Os participantes responderam a um questionário contendo 27 perguntas objetivas sobre conhecimento e frequência das soft skills em suas atividades profissionais. Os participantes também foram solicitados a classificar as soft skills em uma ordem crescente de importância. A amostra foi dividida em subgrupos: A) residentes em Ortodontia; B) ortodontistas com menos de 5 anos de experiência e C) ortodontistas com mais de 5 anos de experiência. As comparações intergrupos foram realizadas usando o teste de Kruskal-Wallis. Diferenças entre os sexos foram comparadas usando o teste de Mann-Whitney (p< 0,05). Resultados: A amostra deste estudo observacional compreendeu 129 ortodontistas experientes e residentes em Ortodontia (92 mulheres, 37 homens) com idade média de 35,3 anos. Entre os entrevistados, 54,6% relataram não ter recebido instruções prévias sobre as soft skills. Todos os entrevistados relataram usar as habilidades interpessoais analisadas com uma frequência semelhante (mediana 4-5). Os residentes relataram acessar com menos frequência (46%) fontes confiáveis de pesquisa bibliográfica. Ortodontistas do sexo feminino relataram buscar ajuda de professores e outros profissionais com mais frequência do que os do sexo masculino. Ética e comunicação foram frequentemente classificadas como as soft skills mais importantes. Com frequência, o gerenciamento de informações e a liderança foram classificados como soft skills menos importantes. Conclusão: Foi demonstrado pouco conhecimento sobre as soft skills por parte de residentes e ortodontistas. A habilidade de comunicação foi frequentemente utilizada e considerada a soft skill mais importante.
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The photoluminescence properties (PL) of Eu3+ hosted in the hydroxide layers of layered double hydroxides (LDHs) enables calibrationless quantification of anions in the interlayers. The concept is demonstrated during the nitrate-to-carbonate ion exchange in Zn2+/Al3+/Eu3+ LDHs and can be implemented as a remote optical sensor to detect intrusion of anions such as Cl- or CO32-.
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Centrosomes are the major microtubule-organizing centers in animals and play fundamental roles in many cellular processes. Understanding how their composition varies across diverse cell types and how it is altered in disease are major unresolved questions, yet currently available centrosome isolation protocols are cumbersome and time-consuming, and they lack scalability. Here, we report the development of centrosome affinity capture (CAPture)-mass spectrometry (MS), a powerful one-step purification method to obtain high-resolution centrosome proteomes from mammalian cells. Utilizing a synthetic peptide derived from CCDC61 protein, CAPture specifically isolates intact centrosomes. Importantly, as a bead-based affinity method, it enables rapid sample processing and multiplexing unlike conventional approaches. Our study demonstrates the power of CAPture-MS to elucidate cell-type-dependent heterogeneity in centrosome composition, dissect hierarchical interactions, and identify previously unknown centrosome components. Overall, CAPture-MS represents a transformative tool to unveil temporal, regulatory, cell-type- and tissue-specific changes in centrosome proteomes in health and disease.
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Proteoma , Proteômica , Animais , Proteoma/metabolismo , Centrossomo/metabolismo , Centro Organizador dos Microtúbulos , Microtúbulos , MamíferosRESUMO
Older individuals with cancer constitute a high-risk group for COVID-19. Entry of the virus into cells occurs through the binding of the S protein with angiotensin-converting enzyme 2, which is mediated by the TMPRSS2 gene and regulated by androgen receptors. Androgen deprivation therapy in patients with prostate cancer inhibits AR-TMPRSS2 interactions, which in turn inhibits the aggressiveness of the infection. We were unable to prove an association between the use of androgen deprivation therapy and a reduction in factors associated with worse clinical outcomes. Most of the data presented show a tendency to favor the outcomes of patients who do not undergo androgen deprivation therapy, which can be explained by the fact that, in general, their clinical conditions are better and their performance status scores are lower than those of patients who undergo androgen deprivation therapy. Abstract presented to the oncology department of A.C.Camargo Cancer Center as a conclusion of the Scientific Initiation. OBJECTIVE: To describe the epidemiological aspects of COVID-19 in patients with prostate cancer who received androgen deprivation therapy and those who did not. METHODS: We retrospectively analyzed the medical records of patients with prostate cancer undergoing androgen deprivation therapy and those who did not undergo androgen deprivation therapy. These patients were treated at the A.C.Camargo Cancer Center between March 2020 and March 2021. RESULTS: Of the 78 patients with prostate cancer and positive RT-PCR test results, 50% were undergoing androgen deprivation therapy, and 49% were experiencing a non-metastatic biochemical relapse. Of these, 80.6% were symptomatic on the day of examination compared to 97.2% in the Control Group. A total of 82.1% of the patients receiving androgen deprivation therapy required hospitalization, with 30.8% admitted to the intensive care unit compared to 21.6% in the Control Group. There was no statistically significant difference in the use of a high-flow oxygen cannula, the need for orotracheal intubation and mechanical ventilation, the need for dialysis, multiple organ failure, or death. A significant difference was found between the groups in terms of the average length of stay in the intensive care unit. CONCLUSION: Androgen deprivation therapy was not associated with protective factors or potential treatments in patients with prostate cancer and COVID-19. Although the number of patients analyzed was limited, and there may have been a selection bias, this is a unique study that cannot be expanded or replicated in similar (unvaccinated) populations.
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COVID-19 , Neoplasias da Próstata , Masculino , Humanos , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/epidemiologia , Antagonistas de Androgênios/uso terapêutico , Androgênios/uso terapêutico , Estudos Retrospectivos , Brasil/epidemiologia , Recidiva Local de Neoplasia/tratamento farmacológicoRESUMO
Metal-organic framework (MOF) materials are attracting increasing interest in the field of electronics due to their structural diversity, intrinsic porosity, and designable host-guest interactions. Here, we report the dielectric properties of a series of robust materials, MFM-300(M) (M = Al, Sc, Cr, Fe, Ga, In), when exposed to different guest molecules. MFM-300(Fe) exhibits the most notable increase in dielectric constant to 35.3 ± 0.3 at 10 kHz upon adsorption of NH3. Structural analysis suggests that the electron delocalization induced by host-guest interactions between NH3 and the MOF host, as confirmed by neutron powder diffraction studies, leads to structural polarization, resulting in a high dielectric constant for NH3@MFM-300(Fe). This is further supported by ligand-to-metal charge-transfer transitions observed by solid-state UV/vis spectroscopy. The high detection sensitivity and stability to NH3 suggest that MFM-300(Fe) may act as a powerful dielectric-based sensor for NH3.
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Conversion of methane (CH4) to ethylene (C2H4) and/or acetylene (C2H2) enables routes to a wide range of products directly from natural gas. However, high reaction temperatures and pressures are often required to activate and convert CH4 controllably, and separating C2+ products from unreacted CH4 can be challenging. Here, we report the direct conversion of CH4 to C2H4 and C2H2 driven by non-thermal plasma under ambient (25 °C and 1 atm) and flow conditions over a metal-organic framework material, MFM-300(Fe). The selectivity for the formation of C2H4 and C2H2 reaches 96% with a high time yield of 334 µmol gcat-1 h-1. At a conversion of 10%, the selectivity to C2+ hydrocarbons and time yield exceed 98% and 2056 µmol gcat-1 h-1, respectively, representing a new benchmark for conversion of CH4. In situ neutron powder diffraction, inelastic neutron scattering and solid-state nuclear magnetic resonance, electron paramagnetic resonance (EPR), and diffuse reflectance infrared Fourier transform spectroscopies, coupled with modeling studies, reveal the crucial role of Fe-O(H)-Fe sites in activating CH4 and stabilizing reaction intermediates via the formation of an Fe-O(CH3)-Fe adduct. In addition, a cascade fixed-bed system has been developed to achieve online separation of C2H4 and C2H2 from unreacted CH4 for direct use. Integrating the processes of CH4 activation, conversion, and product separation within one system opens a new avenue for natural gas utility, bridging the gap between fundamental studies and practical applications in this area.
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Resistance models may quantify the ability of the landscape to impede species' movement and represent suitable habitats. Moreover, the performance of resistance models parameterized by land-use/land cover attributes evidence that the integrity of the environments subject to urban sprawl is poorly understood. In this sense, the study assumed we could identify the forest functional connectivity in a landscape considering the disparity in the landscape mosaic. In this context, we sought to develop a landscape resistance index through structural equation modeling (SEM), supported by the criteria of heat emission, biomass, and anthropogenic barriers, obtained by remote sensing, called observed variables. The landscape studied in the Green Belt Biosphere Reserve of São Paulo has significant remnants of the Atlantic Forest, a biodiversity hotspot. However, our results indicated criteria variability in the landscape modeled through the SEM, obtaining a significant adjustment of the landscape resistance index, with comparative fit index (CFI) of 1.00 and root mean square error of approximation (RMSEA) of 0.00. The index reflects the resistance levels of the land use/land cover, expressed by the class interval, ranging from 0% (1.73) to 100% (493.88), with the highest values associated with the anthropized uses and forest isolation. Thus, our index based on environmental attributes reflects the structure of functional forest connectivity and offers a framework to design forest corridors across landscapes.