A Simple and Efficient Method for Preparing High-Purity α-CaSO4·0.5H2O Whiskers with Phosphogypsum

A simple and efficient approach for the high-purity CaSO₄·2H₂O (DH) whiskers and α-CaSO₄·0.5H₂O (α-HH) whiskers derived from such phosphogypsum (PG) was proposed. The impact of different experimental parameters on supersaturated dissolution–recrystallization and preparation processes of α-CaSO₄·0.5H₂O was elaborated. At 3.5 mol/L HCl concentration, the dissolution temperature and time were 90 °C and 20 min, respectively. After eight cycles and 5–8 times cycles, total crystallization amount of CaSO₄·2H₂O was 21.75 and 9.97 g/100 mL, respectively, from supersaturated HCl solution. The number of cycles affected the shape and amount of the crystal. Higher HCl concentration facilitated CaSO₄·2H₂O dissolution and created a much higher supersaturation, which acted as a larger driving force for phase transformation of CaSO₄·2H₂O to α-CaSO₄·0.5H₂O. The HCl solution system’s optimum experimental conditions for HH whiskers preparation involved acid leaching of CaSO₄·2H₂O sample, with HCl concentration 6.0 mol/L, reaction temperature 80 °C, and reaction time 30 min–60 min. Under the third cycle conditions, α-CaSO₄·0.5H₂O whiskers were uniform in size, clear, and distinct in edges and angles. The length range of α-CaSO₄·0.5H₂O whiskers was from 106 μm to 231 μm and diameter range from 0.43 μm to 1.35 μm, while the longest diameter ratio was 231. Purity of α-CaSO₄·0.5H₂O whiskers was approximately 100%, where whiteness reached 98.6%. The reuse of the solution enables the process to discharge no waste liquid. It provides a new reference direction for green production technology of phosphogypsum.     

Material Optimization Engineering toward xLiFePO4·yLi3V2(PO4)3 Composites in Application-Oriented Li-Ion Batteries

The development of LiFePO₄ (LFP) in high-power energy storage devices is hampered by its slow Li-ion diffusion kinetics. Constructing the composite electrode materials with vanadium substitution is a scientific endeavor to boost LFP’s power capacity. Herein, a series of xLiFePO₄·yLi₃V₂(PO₄)₃ (xLFP·yLVP) composites were fabricated using a simple spray-drying approach. We propose that 5LFP·LVP is the optimal choice for Li-ion battery promotion, owning to its excellent Li-ion storage capacity (material energy density of 413.6 W·h·kg⁻¹), strong machining capability (compacted density of 1.82 g·cm⁻³) and lower raw material cost consumption. Furthermore, the 5LFP·LVP||LTO Li-ion pouch cell also presents prominent energy storage capability. After 300 cycles of a constant current test at 400 mA, 75% of the initial capacity (379.1 mA·h) is achieved, with around 100% of Coulombic efficiency. A capacity retention of 60.3% is displayed for the 300th cycle when discharging at 1200 mA, with the capacity fading by 0.15% per cycle. This prototype provides a valid and scientific attempt to accelerate the development of xLFP·yLVP composites in application-oriented Li-ion batteries.     

Effects of Moisture on NH3 Capture Using Activated Carbon and Acidic Porous Polymer Modified by Impregnation with H3PO4: Sorbent Material Characterized by Synchrotron XRPD and FT-IR

The performances of reactive adsorbents, H₃PO₄/C (activated carbon) and H₃PO₄/A (Amberlyst 35), in removing NH₃ from a waste-gas stream were investigated using a breakthrough column. Accelerated aging tests investigated the effects of the water content on the performance of the adsorbents. Results of breakthrough tests show that the adsorption capacity greatly decreased with the drying time of H₃PO₄/C preparation. Synchrotron XRPD indicated increased amorphous phosphorus species formation with drying time. Nitrogen adsorption-desorption isotherms results further suggested that the evaporation of water accommodated in macropores decreases adsorption capacity besides the formation of the amorphous species. Introducing water moisture to the NH₃ stream increases the adsorption capacity concomitant with the conversion of some NH₄H₂PO₄ to (NH₄)₂HPO₄. Due to the larger pore of cylindrical type and more hydrophilic for acidic porous polymer support, as opposed to slit-type for the activated carbon, the adsorption capacity of H₃PO₄/A is about 3.4 times that of H₃PO₄/C. XRPD results suggested that NH₃ reacts with aqueous H₃PO₄ to form NH₄H₂PO_4, and no significant macropore-water evaporation was observed when acidic porous polymer support was used, as evidenced by N₂ isotherms characterizing used H₃PO₄/A.     

Uptake of Radionuclides 60Co, 137Cs,and 90Sr with α-Fe2O3 and Fe3O4 Particles from Aqueous Environment

In the paper, investigation results of the uptake efficiency of radionuclides ⁶⁰Co, ⁹⁰Sr, and ¹³⁷Cs dissolved in water onto iron oxides α-Fe₂O₃ and Fe₃O₄ are presented. It was found that sorption efficiency increased for higher pH values. Independent of the oxide nature, the uptake characteristics are the best toward ⁶⁰Co and the worst toward ¹³⁷Cs, forming the row as follows: ⁶⁰Co > ⁹⁰Sr > ¹³⁷Cs. The highest sorption ability at pH 9 was found for magnetite Fe₃O₄, which was 93%, 73%, and 26% toward ⁶⁰Co, ⁹⁰Sr, and ¹³⁷Cs, respectively, while the respective percentages for hematite α-Fe₂O₃ were 85%, 41%, and 18%. It was assumed that the main sorption mechanism was ion exchange. That may explain some decrease of the sorption efficiency in drinking water due to the interfering presence of magnesium and calcium cations. The obtained results indicated the feasibility of the tested sorbents and their merits, especially in terms of relatively high uptake coefficients, low costs, availability, and lack of toxicity.     

O Papel da Ecocardiografia sob Estresse na Detecção Precoce de Disfunção Diastólica em Pacientes com Doença Pulmonar Obstrutiva Crônica Não Grave

Background Exertional dyspnea is a common complaint of patients with heart failure with preserved ejection fraction (HFpEF) and chronic obstructive pulmonary disease (COPD). HFpEF is common in COPD and is an independent risk factor for disease progression and exacerbation. Early detection, therefore, has great clinical relevance.Objectives The aim of the study is to detect the frequency of masked HFpEF in non-severe COPD patients with exertional dyspnea, free of overt cardiovascular disease, and to analyze the correlation between masked HFpEF and the cardiopulmonary exercise testing (CPET) parameters.Methods We applied the CPET in 104 non-severe COPD patients with exertional dyspnea, free of overt cardiovascular disease. Echocardiography was performed before and at peak CPET. Cut-off values for stress-induced left and right ventricular diastolic dysfunction (LVDD/ RVDD) were E/e’>15; E/e’>6, respectively. Correlation analysis was done between CPET parameters and stress E/e’. A p-value <0.05 was considered significant.Results 64% of the patients had stress-induced LVDD; 78% had stress-induced RVDD. Both groups with stress LVDD and RVDD achieved lower load, lower V’O₂ and O₂-pulse, besides showing reduced ventilatory efficiency (higher VE/VCO₂ slopes). None of the CPET parameters were correlated to stress-induced left or right E/e’.Conclusion There is a high prevalence of stress-induced diastolic dysfunction in non-severe COPD patients with exertional dyspnea, free of overt cardiovascular disease. None of the CPET parameters correlates to stress-induced E/e’. This demands the performance of Exercise stress echocardiography (ESE) and CPET for the early detection and proper management of masked HFpEF in this population. (Arq Bras Cardiol. 2021; 116(2):259-265)     

A Remodelação do Sistema Nervoso Autônomo Cardíaco pode Desempenhar um Papel na Fibrilação Atrial: Um Estudo do Sistema Nervoso Autônomo e Receptores Miocárdicos

BackgroundThe primary factors that originate and perpetuate atrial fibrillation (AF) are electrical and anatomical substrate alterations. However, the central mechanisms governing AF perpetuation have not been elucidated yet, which is reflected on the modest results of the treatment in patients with long persistent AF.ObjectiveTo evaluate if human intrinsic cardiac autonomic nervous system (ICANS) remodeling, including nervous system fibers and muscarinic and β-adrenergic receptors, play a role in permanent AF.MethodsHeart necropsy samples from thirteen patients with heart disease and permanent AF and thirteen controls without AF were used. By using immunoperoxidase and histomorphometry quantification, we identified the following: the density of all fibers of the ICANS, sympathetic and parasympathetic fibers; and the percentage of myocardium positive for β-adrenergic receptors 1, 2 and 3; G protein-coupled receptor kinase-5 (GRK-5); and muscarinic receptors M1 to M5. The results were compared using ANOVA and nested ANOVA and were adjusted according to the left atrium volume for all variables, and β-blocker use to evaluate the expression of β-receptors and GRK-5.ResultsThere was an overall increase in the density of fibers of the ICANS (p=0.006), especially in atrial sympathetic nerve fibers (p=0.017). Only M1 muscarinic receptors were increased (5.87 vs 2.35, p=0.032). For adrenergic receptors, the results were positive for increased expression of β-3 (37.41 vs 34.18, p=0.039) and GRK-5 (51.16 vs 47.66; p<0.001). β-blocker use had no impact on β-receptor expression.ConclusionIncreased ICANS innervation and remodeling receptor expression in regions prone to triggering AF may play a role in permanent AF.     

Associação entre a Gravidade da Doença Arterial Coronariana e Câncer de Pulmão: Um Estudo Piloto Transversal

BackgroundThe direct relationship between coronary artery disease (CAD) and lung cancer is not well known.ObjectiveTo investigate the association between the anatomical severity of CAD and lung cancer.MethodsThree-hundred study patients, including 75 recently diagnosed lung cancer patients and 225 matched non-cancer patients, underwent coronary angiography during hospitalization without previous percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG). The SYNTAX score (SXscore) was used to assess the severity of CAD. A high SXscore (SXhigh) grade was defined as SXscore > 15 (the highest quartile of the SXscore). The Cochran-Armitage test for trend was used to assess the distribution of patients’ SXscores. Logistic regression analysis was used to assess the association between the severity of CAD and lung cancer. P-values were set when significance level was 5%.ResultsThe distribution trend of patients’ SXscore by quartiles was different between lung cancer patients and control patients (from the lowest to the highest quartile: 20.0%, 20.0%, 24.0%, 36.0% vs. 26.7%, 26.2%, 25.8%, 21.3%, p=0.022). The SX high rate was higher in lung cancer patients than in control patients (36.0% vs. 21.3%, p=0.011).The highest quartile of the SXscore showed higher risk of lung cancer in comparison to the lowest quartile (OR: 2,250, 95%CI: 1,077 to 4,699 ; P-trend= 0.016). After adjustment, patients in the highest quartile of the SXscore had higher risk of lung cancer (OR: 2,149, 95%CI: 1,008 to 4,584; P-trend= 0.028). Patients with high SXscore (> 15) had 1,985 times more chances of having lung cancer (95%CI: 1,105–3,563, P= 0.022).ConclusionsThe anatomical severity of CAD is associated with the risk of lung cancer, which indicates that a thorough lung cancer screening may be significant among severe CAD patients.     

Investigação Citogenômica de Crianças com Doença Cardíaca Congênita: Experiência de um Centro no Brasil

BackgroundSome syndromes have specific and easily recognizable features, while others may be more complex to identify and may present different phenotypic manifestations, for example. An etiological diagnosis is important to understand the nature of the disease, to establish the prognosis and to start the treatment, allowing the inclusion of patients in society and reducing the financial cost of such diseases.ObjectiveThe initial proposal of this study was cytogenetic screening for the detection of the 22q11.2 deletion syndrome in consecutive newborns and infants with congenital heart disease using the multiplex ligation-dependent probe amplification (MLPA) technique. Therefore, throughout our research, other genomic alterations were identified in these cardiac patients. Thus, our objective was extended to investigate these other cytogenetic alterations.MethodsWe investigated 118 neonates with congenital heart diseases born consecutively during one year using the MLPA technique.ResultsThe MLPA technique allowed the detection of 22q11.2DS in 10/118 patients (8.5%). Other genomic alterations were also identified in 6/118 patients (5%): 1p36 del, 8p23 del (2 cases), 7q dup, 12 dup and 8q24 dup.ConclusionThis study highlights the relevance of detecting genomic alterations that are present in newborns and infants with congenital cardiac diseases using cytogenomic tools.     

Estudo Comparativo entre Receptores de Desfibriladores Subcutâneos e Transvenosos em Relação à Tolerância ao Procedimento de Implante e Percepção da Qualidade de Vida

BackgroundThe totally subcutaneous implantable cardioverter-defibrillator (S-ICD) is a safe alternative to the conventional transvenous ICD (TV-ICD) system to prevent sudden death.ObjectiveTo compare the impact of the type of ICD system and surgical technique on patients’ quality of life, as well as the severity of discomfort and pain, between S-ICD and TV-ICD recipients.MethodsConsecutively implanted patients with an S-ICD system were matched with patients with a TV-ICD system. In addition, patients undergoing S-ICD implantation after removal of a TV-ICD due to complications were included. Quality of life (measured with the 12-item short-form health survey) and severity of pain and discomfort were evaluated. Statistical significance was defined as p < 0.05.ResultsA total of 64 patients implanted with S-ICD or TV-ICD under local anesthesia and conscious sedation were analyzed. Patients with S-ICD and TV-ICD systems did not differ significantly in quality of life scores. S-ICD patients had a higher level of perioperative pain; no differences were found regarding severity of intraoperative pain. The magnitude of aesthetic discomfort and sleep disturbances did not differ between groups. An S-ICD was implanted in 7 additional patients after removal of a TV-ICD. All but one of these patients recommended the S-ICD system.ConclusionsThe type of ICD system and the surgical technique have negligible impact on patients’ quality of life. These results suggest that conscious sedation, provided by an experienced electrophysiology team, could be considered as an alternative to general anesthesia to manage patients undergoing S-ICD implantation.     

Evidence of sp2-like Hybridization of Silicon Valence Orbitals in Thin and Thick Si Grown on α-Phase Si(111)√3 × √3R30°-Bi

One-monolayer (ML) (thin) and 5-ML (thick) Si films were grown on the α-phase Si(111)√3 × √3R30°-Bi at a low substrate temperature of 200 °C. Si films have been studied in situ by reflection electron energy loss spectroscopy (REELS) and Auger electron spectroscopy, as a function of the electron beam incidence angle α and low-energy electron diffraction (LEED), as well as ex situ by grazing incidence X-ray diffraction (GIXRD). Scanning tunneling microscopy (STM), and scanning tunneling spectroscopy (STS) were also reported. The REELS spectra, taken at the Si K absorption edge (~1.840 KeV), reveal the presence of two distinct loss structures attributed to transitions 1s→π* and 1s→σ* according to their intensity dependence on α, attesting to the sp²-like hybridization of the silicon valence orbitals in both thin and thick Si films. The synthesis of a silicon allotrope on the α-phase of Si(111)√3 × √3R30°-Bi substrate was demonstrated by LEED patterns and GIXRD that discloses the presence of a Si stack of 3.099 (3) Å and a √3 × √3 unit cell of 6.474 Å, typically seen for multilayer silicene. STM and STS measurements corroborated the findings. These measurements provided a platform for the new √3 × √3R30° Si allotrope on a Si(111)√3 × √3 R30°-Bi template, paving the way for realizing topological insulator heterostructures from different two-dimensional materials, Bi and Si.     

The Long and Short of β2-agonists

For patients whose asthma is not adequately controlled with inhaled corticosteroid (ICS) therapy alone, increasing the dose of ICS or the addition of a long-acting β₂-agonist is recommended. Greater improvements in lung function are achieved with the addition of a long-acting β₂-agonist to ICS therapy, rather than doubling the dose of ICS. Formoterol and salmeterol have a similarly long duration of effect (up to 12 h). However, as a result of their different chemical structures, there are marked pharmacological differences in the mechanism of action which affect their speeds of onset. These differences amount to a more rapid onset of effect for formoterol compared with salmeterol. Long-acting β₂-agonists appear to be well tolerated at elevated doses. These two features (tolerability at high doses and rapid onset of effect) support the use of formoterol as a reliever medication in addition to use in maintenance therapy. The long-acting β₂-agonists can be considered as beneficial additions to ICS therapy for the management of moderate-to-severe asthma.     

Prevalência e Fatores Associados à SRAG por COVID-19 em Adultos e Idosos com Doença Cardiovascular Crônica

BackgroundThe presence of Cardiovascular Disease (CVD) in individuals infected with COVID-19 may imply a worse prognosis.ObjectiveTo describe the prevalence of Severe Acute Respiratory Syndrome (SARS) by COVID-19 and to analyze the factors associated with this condition in adults and the elderly with cardiovascular disease in Brazil until the 30th Epidemiological Week of 2020.MethodsCross-sectional study conducted with data from the Influenza Epidemiological Surveillance Information System (Sistema de Informação de Vigilância Epidemiológica da Gripe – SIVEP-Gripe), referring to the SARS notification forms of hospitalized individuals in Brazil, between the 1st and 30th Epidemiological Week of 2020. Adults and the aged (≥ 18 years old) with CVD. The dependent variable was SRAG confirmation by COVID-19 and factors related to sociodemographic characteristics, signs and symptoms, and clinical factors were analyzed. Poisson regression with robust variance was applied. The level of significance adopted was 5%.ResultsNotifications from 116,343 individuals were analyzed. Of these, 61.9% were diagnosed with SARS by COVID-19. The prevalence of the outcome was 4% lower in women (95%CI: 0.94–0.99) and 18% lower in rural areas (95%CI: 0.77–0.87). There was a higher prevalence in the 50 to 59 age group (95%CI: 1.09–1.48) and in the northeast region (95%CI: 1.72–1.91). Fever, cough, admission to the ICU, use of ventilatory support, and nosocomial cases were also significantly associated with a higher probability of SRAS by COVID-19 in these individuals.ConclusionThere is a high prevalence of SARS by COVID-19 in adults and aged people with CVD in Brazil. Factors associated with sociodemographic and clinical characteristics, signs, and symptoms were associated.     

Layered Perovskites BaM2In2O7 (M = La,Nd): From the Structure to the Ionic (O2−, H+) Conductivity

The design of new oxide compounds that can be used as oxygen- or proton-conducting electrolytes for solid oxide fuel cells is actively in progress. Despite the intensive research activities regarding electrolytes with perovskite/fluorite structures, the search for other structural alternatives is of paramount importance. In this study we focus on a novel material with significantly improved properties for the electrochemical purposes. The two-layered BaNd₂In₂O₇ perovskite with a Ruddlesden–Popper structure was investigated as a protonic conductor for the first time. In detail, its local structure, water uptake, and the ionic (O²⁻, H⁺) conductivity were comprehensively studied. The nature of rare-earth elements (M = La, Nd) in the structure of BaM₂In₂O₇ on the structural and transport properties was revealed. The presented analysis showed that the composition of BaNd₂In₂O₇ is nearly pure proton conductor below 350 °C. This work opens up a new way in the design of protonic conductors with double-layered perovskite structure.     

Fibrose Cardíaca e Mudanças Evolutivas na Função Ventricular Esquerda em Pacientes com Cardiopatia Chagásica Crônica

BackgroundChagas heart disease (CHD) is a slow progressing condition with fibrosis as the main histopathological finding.ObjectivesTo study if cardiac fibrosis increases over time and correlates with increase in left ventricular (LV) size and reduction of ejection fraction (EF) in chronic CHD.MethodsRetrospective study that included 20 individuals (50% men; 60±10 years) with chronic CHD who underwent two cardiac magnetic resonance imaging (MRI) with late gadolinium enhancement with a minimum interval of four years between tests. LV volume, EF, and fibrosis mass were determined by cardiac MRI. Associations of fibrosis mass at the first cardiac MRI and changes in LV volume and EF at the second cardiac MRI were tested using logistic regression analysis. P values <0.05 were considered significant.ResultsPatients were classified as follows: A (n=13; changes typical of CHD in the electrocardiogram and normal global and segmental LV systolic function) and B1 (n=7; LV wall motion abnormality and EF≥45%). Mean time between cardiac MRI studies was 5.4±0.5 years. LV fibrosis (in %LV mass) increased from 12.6±7.9% to 18.0±14.1% between MRI studies (p=0.02). Cardiac fibrosis mass at baseline was associated with decrease in >5 absolute units in LV EF from the first to the second MRI (OR 1.48, 95% CI 1.03-2.13, p=0.03). LV fibrosis mass was larger and increased between MRI studies in the group that presented decrease in LV EF between the tests.ConclusionsEven patients at an initial stage of CHD show an increase in myocardial fibrosis over time, and the presence of LV fibrosis at baseline is associated with a decrease in LV systolic function.     

Reinforced 3D Composite Structures of γ-, α-Al2O3 with Carbon Nanotubes and Reduced GO Ribbons Printed from Boehmite Gels

The ability of boehmite to form printable inks has sparked interest in the manufacturing of 3D alumina (Al₂O₃) and composite structures by enabling direct ink writing methods while avoiding the use of printing additives. These materials may exhibit high porosity due to the printing and sintering procedures, depending on the intended application. The 3D-printed porous composite structures of γ-Al₂O₃ and α-Al₂O₃ containing 2 wt.% of carbon nanotubes or reduced graphene oxide ribbons were fabricated from boehmite gels, followed by different heat treatments. The reinforcing effect of these carbon nanostructures was evidenced by compression tests carried out on the different alumina structures. A maximum relative increase of 50% in compressive strength was achieved for the γ-Al₂O₃ composite structure reinforced with reduced graphene oxide ribbons, which was also accompanied by an increase in the specific surface area.     

Intervenção Coronariana Percutânea em Lesões não Protegidas de Tronco

BackgroundThe advent of drug-eluting stents allowed the percutaneous coronary intervention to present safe results in lesions in the left main coronary artery.ObjectivesTo analyze the results of the percutaneous treatment of unprotected left main coronary artery lesion with the use of intravascular ultrasound.MethodsStudy of consecutive case series carried out from January 2010 to December 2018. Clinical data were collected from patients as well as prognostic scores and data on coronary lesion. Low-grade residual lesion (less than 50%) on angiography and minimum luminal area greater than 6 mm²on intravascular ultrasound were considered successful. The adopted significance level was 5%.Results107 cases were analyzed. The multivessel lesion was predominant, with most (39.25%) of the lesions being found in three vessels in addition to the left main coronary artery. The SYNTAX score had a mean of 46.80 (SD: 22.95), and 70 (65.42%) patients had a SYNTAX score above 32 points. Angiographic success of percutaneous intervention was considered in 106 (99.06%) patients. The overall rate of major cardiac and cerebrovascular events in the hospital outcome was 6.54%, being similar in patients with SYNTAX score ≤ 32 (8.10%) and ≥ 33 (5.71%; p = 0.68).ConclusionsPercutaneous intervention in cases of unprotected left main coronary artery lesion was safely performed and presented excellent results. Considerable angiographic success of treatment guided by intravascular ultrasound was achieved. The rate of major cardiac and cerebrovascular events was similar between patients at low and high risks.