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1.
Artigo em Inglês | MEDLINE | ID: mdl-38967398

RESUMO

OBJECTIVE: Posterior left atrial wall isolation (PWI) plus traditional pulmonary vein isolation (PVI) has been proposed as a promising intervention to decrease atrial fibrillation (AF) recurrence. We aim to investigate the efficacy and safety of adding PWI to the traditional PVI in patients with AF. METHODS: A systematic review and meta-analysis was conducted using synthesizing randomized controlled trials (RCTs) retrieved by systematically searching PubMed, Web of Science, SCOPUS, EMBASE, and Cochrane through June 14, 2023. We used Stata version 17 to pool dichotomous data using risk ratio (RR) and continuous data using mean difference (MD), with a 95% confidence interval (CI) (PROSPERO ID: CRD42023446227). RESULTS: We included 11 RCTs with a total number of 1534 patients. Combined ablation with PWI + PVI was not associated with any significant difference over PVI only regarding the recurrence of clinical AF (RR: 0.86 with 95% CI [0.70-1.06]), all atrial arrhythmia (RR: 0.93 with 95% CI [0.82-1.07]), nonatrial fibrillation arrhythmia (RR: 1.22 with 95% CI [0.97-1.53]), early AF (RR: 0.89 with 95% CI [0.62-1.27]), and antiarrhythmic drugs at discharge (RR: 0.83 with 95% CI [0.67-1.04]). However, it was associated with increased total ablation duration (minutes) (MD: 12.58 with 95% CI [6.80-18.37]) and total procedure duration (minutes) (MD: 16.77 with 95% CI [9.63-23.91]), without any significant difference regarding adverse events (RR: 1.05 with 95% CI [0.63-1.74]). CONCLUSION: While the pooled data from PWI + PVI using point-by-point radiofrequency did not suggest a benefit in the recurrence of various atrial arrhythmias compared to PVI alone, PWI+PVI using direct posterior wall ablation, especially with cryoballoon, demonstrated a significant reduction in recurrence of AF/atrial arrhythmias. Also, PWI + PVI significantly increased the ablation and total procedure durations.

2.
Clin Rheumatol ; 43(7): 2203-2214, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38802670

RESUMO

Immunosuppressants, such as methotrexate (MTX), can suppress the COVID-19 vaccine response in patients with autoimmune diseases. Thus, this study aims to evaluate the effects of MTX hold following COVID-19 vaccination on vaccine efficacy response. A systematic review and meta-analysis of relevant studies retrieved from Web of Science, SCOPUS, PubMed, and CENTRAL from inception until Oct 1, 2023, was conducted. Covidence was used to screen the eligible articles, and all relevant outcomes data were synthesized using risk ratios (RRs) or standardized mean differences (SMDs) with 95% confidence intervals (CIs) in meta-analysis models within RevMan 5.4. PROSPERO ID: CRD42024511628. Four studies with a total of 762 patients with autoimmune inflammatory disorders were included. Holding MTX following the COVID-19 vaccination for approximately 2 weeks was associated with significantly higher antibody titer (SMD: 0.70, 95% CI [0.54, 0.87], P < 0.00001). However, the flare rate was significantly higher in the MTX hold group based on CDAI > 10 or DAS28-CRP > 1.2 either after 1st dose (RR: 2.49 with 95% CI [1.39, 4.47], P = 0.002) or 2nd dose (RR: 2.16 with 95% CI [1.37, 3.41], P = 0.0009) and self-reported disease flare (RR: 1.71 with 95% CI [1.35, 2.17], P < 0.00001). Holding MTX for 2 weeks after the COVID-19 vaccination resulted in significantly higher antibody titer but also had a higher disease flare rate, necessitating cautious clinical monitoring during this period. There is still a need to investigate safer MTX hold duration, considering patients' vulnerability to COVID-19, disease status, and demographics while adopting this strategy.


Assuntos
Doenças Autoimunes , Vacinas contra COVID-19 , COVID-19 , Imunossupressores , Metotrexato , Humanos , Metotrexato/uso terapêutico , COVID-19/prevenção & controle , COVID-19/imunologia , Doenças Autoimunes/tratamento farmacológico , Doenças Autoimunes/imunologia , Imunossupressores/uso terapêutico , SARS-CoV-2/imunologia , Eficácia de Vacinas
3.
Thromb J ; 22(1): 45, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38807186

RESUMO

BACKGROUND: Clinical decision support systems (CDSS) have been utilized as a low-cost intervention to improve healthcare process measures. Thus, we aim to estimate CDSS efficacy to optimize adherence to oral anticoagulant guidelines in eligible patients with atrial fibrillation (AF). METHODS: A systematic review and meta-analysis of randomized controlled trials (RCTs) retrieved from PubMed, WOS, SCOPUS, EMBASE, and CENTRAL through August 2023. We used RevMan V. 5.4 to pool dichotomous data using risk ratio (RR) with a 95% confidence interval (CI). PROSPERO ID: CRD42023471806. RESULTS: We included nine RCTs with a total of 25,573 patients. There was no significant difference, with the use of CDSS compared to routine care, in the number of patients prescribed anticoagulants (RR: 1.06, 95% CI [0.98, 1.14], P = 0.16), the number of patients prescribed antiplatelets (RR: 1.01 with 95% CI [0.97, 1.06], P = 0.59), all-cause mortality (RR: 1.19, 95% CI [0.31, 4.50], P = 0.80), major bleeding (RR: 0.84, 95% CI [0.21, 3.45], P = 0.81), and clinically relevant non-major bleeding (RR: 1.05, 95% CI [0.52, 2.16], P = 0.88). However, CDSS was significantly associated with reduced incidence of myocardial infarction (RR: 0.18, 95% CI [0.06, 0.54], P = 0.002) and cerebral or systemic embolic event (RR: 0.11, 95% CI [0.01, 0.83], P = 0.03). CONCLUSION: We report no significant difference with the use of CDSS compared to routine care in anticoagulant or antiplatelet prescription in eligible patients with AF. CDSS was associated with a reduced incidence of myocardial infarction and cerebral or systemic embolic events.

4.
Anal Methods ; 16(18): 2777-2809, 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38639474

RESUMO

Paper-based sensors, often referred to as paper-based analytical devices (PADs), stand as a transformative technology in the field of analytical chemistry. They offer an affordable, versatile, and accessible solution for diverse analyte detection. These sensors harness the unique properties of paper substrates to provide a cost-effective and adaptable platform for rapid analyte detection, spanning chemical species, biomolecules, and pathogens. This review highlights the key attributes that make paper-based sensors an attractive choice for analyte detection. PADs demonstrate their versatility by accommodating a wide range of analytes, from ions and gases to proteins, nucleic acids, and more, with customizable designs for specific applications. Their user-friendly operation and minimal infrastructure requirements suit point-of-care diagnostics, environmental monitoring, food safety, and more. This review also explores various fabrication methods such as inkjet printing, wax printing, screen printing, dip coating, and photolithography. Incorporating nanomaterials and biorecognition elements promises even more sophisticated and sensitive applications.


Assuntos
Técnicas Biossensoriais , Papel , Técnicas Biossensoriais/métodos , Técnicas Biossensoriais/instrumentação , Humanos , Desenho de Equipamento , Monitoramento Ambiental/métodos , Monitoramento Ambiental/instrumentação , Ácidos Nucleicos/análise , Proteínas/análise , Nanoestruturas/química
5.
Chemosphere ; 357: 141935, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38636909

RESUMO

The conversion of waste biomass into a value-added carbonaceous nanomaterial highlights the appealing power of biomass valorization. The advantages of using sustainable and cheap biomass precursors exhibit the tremendous opportunity for boosting energy production and their application in environmental remediation processes. This review emphasis the development and production of carbon-based nanomaterials derived from biomass, which possess favourable characteristics such as biocompatibility and photoluminescence. The advantages and limitations of various nanomaterials synthesised from different precursors were also discussed with insights into their physicochemical properties. The surface morphology of the porous nanomaterials is also explored along with their characteristic properties like regenerative nature, non-toxicity, ecofriendly nature, unique surface area, etc. The incorporation of various functional groups confers superiority of these materials, resulting in unique and advanced functional properties. Further, the use of these biomass derived nanomaterials was also explored in different applications like adsorption, photocatalysis and sensing of hazardous pollutants, etc. The challenges and outcomes obtained from different carbon-based nanomaterials are briefly outlined and discussed in this review.


Assuntos
Biomassa , Carbono , Recuperação e Remediação Ambiental , Nanoestruturas , Recuperação e Remediação Ambiental/métodos , Nanoestruturas/química , Carbono/química , Adsorção , Poluentes Ambientais/química , Catálise
6.
Artigo em Inglês | MEDLINE | ID: mdl-38460090

RESUMO

BACKGROUND: High-power short-duration (HPSD) ablation has emerged as an alternative to conventional standard-power long-duration (SPLD) ablation. We aim to assess the efficacy and safety of HPSD versus SPLD for atrial fibrillation (AF) ablation. METHODS: A systematic review and meta-analysis of randomized controlled trials (RCTs) retrieved from PubMed, WOS, SCOPUS, EMBASE, and CENTRAL were performed through August 2023. We used RevMan V. 5.4 to pool dichotomous data using risk ratio (RR) and continuous data using mean difference (MD) with a 95% confidence interval (CI). PROSPERO ID: CRD42023471797. RESULTS: We included six RCTs with a total of 694 patients. HPSD was significantly associated with a decreased total procedure time (MD: -22.88 with 95% CI [-36.13, -9.63], P = 0.0007), pulmonary vein isolation (PVI) time (MD: -19.73 with 95% CI [-23.93, -15.53], P < 0.00001), radiofrequency time (MD: -10.53 with 95% CI [-12.87, -8.19], P < 0.00001). However, there was no significant difference between HPSD and SPLD ablation with respect to the fluoroscopy time (MD: -0.69 with 95% CI [-2.00, 0.62], P = 0.30), the incidence of esophageal lesions (RR: 1.15 with 95% CI [0.43, 3.07], P = 0.77), and the incidence of first pass isolation (RR: 0.98 with 95% CI [0.88, 1.08], P = 0.65). CONCLUSION: HPSD ablation was significantly associated with decreased total procedure time, PVI time, and radiofrequency time compared with SPLD ablation. On the contrary, SPLD ablation was significantly associated with low maximum temperature.

7.
Clin Neuroradiol ; 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38453701

RESUMO

BACKGROUND AND PURPOSE: Optimal clinical outcome with successful recanalization from endovascular thrombectomy (EVT) requires optimal blood pressure (BP) management. We aimed to evaluate the efficacy and safety of the intensive BP target (< 140 mm Hg) versus the standard BP target (< 180 mm Hg) after EVT for acute ischemic stroke. METHODS: We conducted a systematic review and meta-analysis synthesizing evidence from randomized controlled trials (RCTs) obtained from PubMed, Embase Cochrane, Scopus, and WOS until September 7th, 2023. We used the fixed-effect model to report dichotomous outcomes using risk ratio (RR) and continuous outcomes using mean difference (MD), with a 95% confidence interval (CI). PROSPERO ID: CRD42023463206. RESULTS: We included four RCTs with 1559 patients. There was no difference between intensive BP and standard BP targets regarding the National Institutes of Health Stroke Scale (NIHSS) change after 24 h [MD: 0.44 with 95% CI (0.0, 0.87), P = 0.05]. However, the intensive BP target was significantly associated with a decreased risk of excellent neurological recovery (mRS ≤ 1) [RR: 0.87 with 95% CI (0.76, 0.99), P = 0.03], functional independence (mRS ≤ 2) [RR: 0.81 with 95% CI (0.73, 0.90), P = 0.0001] and independent ambulation (mRS ≤ 3) [RR: 0.85 with 95% CI (0.79, 0.92), P < 0.0001]. CONCLUSIONS: An intensive BP target after EVT is associated with worse neurological recovery and significantly decreased rates of functional independence and independent ambulation compared to the standard BP target. Therefore, the intensive BP target should be avoided after EVT for acute ischemic stroke.

8.
Chemosphere ; 353: 141542, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38428535

RESUMO

The escalating global concern regarding antibiotic pollution necessitates the development of advanced water treatment strategies. This study presents an innovative approach through the fabrication and evaluation of a Polyethersulfone (PES) membrane adorned with GO-TiO2 nanocomposites. The objective is to enhance the removal efficiency of various antibiotics, addressing the challenge of emerging organic compounds (EOCs) in water systems. The nanocomposite membranes, synthesized via the phase inversion method, incorporate hydrophilic agents, specifically GO-TiO2 nanocomposites and Polyvinylpyrrolidone (PVP). The resultant membranes underwent comprehensive characterization employing AFM, EDS, tensile strength testing, water contact angle measurements, and FESEM to elucidate their properties. Analysis revealed a substantial improvement in the hydrophilicity of the modified membranes attributed to the presence of hydroxyl groups within the GO-TiO2 structure. AFM images demonstrated an augmentation in surface roughness with increasing nanocomposite content. FESEM images unveiled structural modifications, leading to enhanced porosity and augmented water flux. The pure water flux elevated from 0.980 L/m2.h-1 for unmodified membranes to approximately 6.85 L/m2.h-1 for membranes modified with 2 wt% nanocomposites. Membrane performance analysis indicated a direct correlation between nanocomposite content and antibiotic removal efficiency, ranging from 66.52% to 89.81% with 4 wt% nanocomposite content. Furthermore, the nanocomposite-modified membrane exhibited heightened resistance to fouling. The efficacy of the membrane extended to displaying potent antibacterial properties against microbial strains, including S. aureus, E. coli, and Candida. This study underscores the immense potential of GO-TiO2 decorated PES membranes as a sustainable and efficient solution for mitigating antibiotic contamination in water systems. The utilization of nanocomposite membranes emerges as a promising technique to combat the presence of EOC pollutants, particularly antibiotics, in water bodies, thus addressing a critical environmental concern.


Assuntos
Nanocompostos , Polímeros , Povidona , Sulfonas , Antibacterianos/farmacologia , Azitromicina , Amoxicilina , Ciprofloxacina , Escherichia coli , Staphylococcus aureus , Nanocompostos/química , Membranas Artificiais
9.
Cureus ; 16(2): e54606, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38524022

RESUMO

Background There are several patterns of metastatic spread from endometrial cancer (EC). Although studies have been conducted to study the EC population with distant metastasis in the bone and lungs, there is still a lack of studies on liver metastasis. This study aims to evaluate and assess the clinical features and prognostic factors of EC patients with liver metastasis. Methodology We conducted a retrospective cohort study adhering to the guidelines for reporting observational research. We utilized the Surveillance, Epidemiology, and End Results database to gather data on female patients diagnosed with EC and reported liver metastasis. We estimated survival curves using the Kaplan-Meier method and evaluated differences in survival using the log-rank test. We also conducted univariable and multivariable Cox proportional hazards regression analyses to determine the hazard ratios with 95% confidence intervals for overall survival (OS) and identify factors that impact survival. Results We analyzed data from 1,034 EC patients with liver metastasis. Median OS after liver metastasis was six months, and cancer-specific survival was seven months. Univariate Cox regression analysis revealed several factors associated with decreased OS in EC patients. These included age (≥60 years), non-endometrioid and sarcoma histological subtypes, absence of surgery, no chemotherapy, and the presence of distant metastasis to the lung, brain, and bone. Conversely, married marital status and white race were linked to a better prognosis. Subsequent multivariate Cox regression analysis identified age (≥60 years), non-endometrioid histological subtype, absence of surgery, no chemotherapy, and the presence of distant metastasis to lung, brain, and bone remaining as independent risk factors for decreased OS. In contrast, the white race still emerged as an independent prognostic factor for better OS. Conclusions Various risk factors, such as age, race, lung, bone, or brain metastasis, as well as chemotherapy and surgery, may influence the prognosis of individuals with primary EC liver metastases.

10.
Waste Manag Res ; : 734242X231223914, 2024 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-38366790

RESUMO

This study introduces an innovative approach for enhancing oil-water emulsion separation using a polyethersulfone (PES) membrane embedded with a nanocomposite of graphene oxide (GO) and silver oxide (AgO). The composite membrane, incorporating PES and polyvinyl chloride (PVC), demonstrates improved hydrophilicity, structural integrity and resistance to fouling. Physicochemical characterization confirms successful integration of GO and AgO, leading to increased tensile strength, porosity and hydrophilicity. Filtration tests reveal substantial improvements in separating various oils from contaminated wastewater, with the composite membrane exhibiting superior efficiency and reusability compared to pristine PES membranes. This research contributes to the development of environmentally friendly oil-water separation methods with broad industrial applications.

11.
Waste Manag Res ; : 734242X241227379, 2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38353237

RESUMO

This study addresses the urgent issue of water pollution caused by iron (Fe) and manganese (Mn) ions. It introduces an innovative approach using graphene oxide (GO) and GO-decorated polyethersulphone (PES) membranes to efficiently remove these ions from contaminated water. The process involves integrating GO into PES membranes to enhance their adsorption capacity. Characterization techniques, including scanning electron microscopy, Fourier-transform infrared, and contact angle measurements, were used to assess structural and surface properties. The modified membranes demonstrated significantly improved adsorption compared to pristine PES. Notably, they achieved over 94% removal of Mn2+ and 93.6% of Fe2+ in the first filtration cycle for water with an initial concentration of 100 ppm. Continuous filtration for up to five cycles maintained removal rates above 60%. This research advances water purification materials, offering a promising solution for heavy metal ion removal. GO-decorated PES membranes may find application in large-scale water treatment, addressing environmental and public health concerns.

12.
Cardiooncology ; 10(1): 10, 2024 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-38395955

RESUMO

BACKGROUND: Cardiotoxicity is one of the most common adverse events of the chemotherapy. Physical exercise was shown to be cardioprotective. We aim to estimate the efficacy and safety of exercise in cancer patients receiving cardiotoxic chemotherapy. METHODS: We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs), which were retrieved by systematically searching PubMed, Web of Science, SCOPUS, Cochrane, Clinical Trials.gov, and MedRxiv through July 17th, 2023. We used RevMan V. 5.4 to pool dichotomous data using risk ratio (RR) and continuous data using mean difference (MD), with a 95% confidence interval (CI). PROSPERO ID: CRD42023460902. RESULTS: We included thirteen RCTs with a total of 952 patients. Exercise significantly increased VO2 peak (MD: 1.95 with 95% CI [0.59, 3.32], P = 0.005). However, there was no significant effect regarding left ventricular ejection fraction, global longitudinal strain, cardiac output, stroke volume, left ventricular end-diastolic volume, left ventricular end-systolic volume, E/A ratio, resting heart rate, peak heart rate, resting systolic blood pressure, and resting diastolic blood pressure. Also, there was no significant difference regarding any adverse events (AEs) (RR: 4.44 with 95% CI [0.47, 41.56], P = 0.19), AEs leading to withdrawal (RR: 2.87 with 95% CI [0.79, 10.43], P = 0.11), serious AEs (RR: 3.00 with 95% CI [0.14, 65.90], P = 0.49), or all-cause mortality (RR: 0.25 with 95% CI [0.03, 2.22], P = 0.21). CONCLUSION: Exercise is associated with increased VO2 peak in cancer patients receiving cardiotoxic chemotherapy. However, there was no significant difference between exercise and usual care regarding the echocardiographic and safety outcomes.

13.
Chemosphere ; 353: 141491, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38395365

RESUMO

Photocatalysis has emerged as a promising approach for generating solar chemical and organic transformations under the solar light spectrum, employing polymer photocatalysts. In this study, our aim is to achieve the regeneration of NADH and fixation of nitroarene compounds, which hold significant importance in various fields such as pharmaceuticals, biology, and chemistry. The development of an in-situ nature-inspired artificial photosynthetic pathway represents a challenging task, as it involves harnessing solar energy for efficient solar chemical production and organic transformation. In this work, we have successfully synthesized a novel artificial photosynthetic polymer, named TFc photocatalyst, through the Friedel-Crafts alkylation reaction between triptycene (T) and a ferrocene motif (Fc). The TFC photocatalyst is a promising material with excellent optical properties, an appropriate band gap, and the ability to facilitate the regeneration of NADH and the fixation of nitroarene compounds through photocatalysis. These characteristics are necessary for several applications, including organic synthesis and environmental remediation. Our research provides a significant step forward in establishing a reliable pathway for the regeneration and fixation of solar chemicals and organic compounds under the solar light spectrum.


Assuntos
NAD , Energia Solar , Fotossíntese , Luz , Luz Solar , Compostos Orgânicos/química
14.
J Endocr Soc ; 8(2): bvad177, 2024 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-38213906

RESUMO

Background: Insulin icodec is a novel basal insulin analog with once-weekly subcutaneous administration. We aim to estimate the efficacy and safety of insulin icodec vs long-acting insulin (insulin glargine and degludec) in type II diabetic patients. Methods: We conducted a systematic review and meta-analysis synthesizing randomized controlled trials (RCTs), which were retrieved by systematically searching PubMed, Web of Science, SCOPUS, and Cochrane through May 29, 2023. We used RevMan V. 5.4 to pool dichotomous data using risk ratio (RR) and continuous data using mean difference (MD) with a 95% confidence interval (CI). Our primary outcome was glycated hemoglobin (HbA1C) change. Results: We included 7 RCTs with a total of 3183 patients. Insulin icodec was associated with significantly decreased HbA1C (MD: -0.15 with 95% CI [-0.24, -0.06], P = .002) and increased percentage of time with glucose in range (TIR) (MD: 4.06 with 95% CI [2.06, 6.06], P = .0001). However, insulin icodec was associated with increased body weight (MD: 0.57 with 95% CI [0.45, 0.70], P = .00001). Also, there was no difference regarding any serious adverse events (AEs) (RR: 0.96 with 95% CI [0.76, 1.20], P = .7) or AEs leading to withdrawal (RR: 1.54 with 95% CI [0.84, 2.82], P = .16). However, insulin icodec was associated with increased any AEs incidence (RR: 1.06 with 95% CI [1.01, 1.12], P = .02). Conclusion: Insulin icodec was associated with decreased HbA1C, increased TIR, with similar hypoglycemic and serious AEs. However, it was also associated with increased body weight and the incidence of any AEs.

15.
Ann Otol Rhinol Laryngol ; 133(2): 196-204, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37688447

RESUMO

BACKGROUND: The defects of the upper third of the auricle are considered significant reconstructive challenges, as they require frequent operations with a high risk of morbidity at the donor site and result in unacceptable cosmetic abnormalities. OBJECTIVE: Is to perform the reconstruction of a full-thickness auricular defect located in the upper third of the ear using a conchal cartilage graft with postauricular flap coverage, aiming to minimize both donor and recipient morbidity. PATIENTS AND METHODS: The current study included 20 patients with unilateral upper-third auricular defects. The repair involved 2 components: a cartilage graft from the concha to provide structural support and a flap for coverage. Follow-up was conducted for 6 months after the operation. RESULTS: Successful outcomes were achieved in both subjective and doctors' assessments. Regarding subjective outcomes, 85% of the patients reported high satisfaction (P < .001). In terms of doctors' subjective assessment, 90% of the patients had excellent results (P < .001). Mild early and postoperative complications, if encountered, resolved spontaneously. CONCLUSION: The use of a combined conchal cartilage graft and postauricular flap in treating a full-thickness upper third auricular defect is safe and effective, with no major complications. The technique preserves the cosmetic and functional outcomes of the auricle, providing an excellent color match and minimal donor-site morbidity.


Assuntos
Pavilhão Auricular , Procedimentos de Cirurgia Plástica , Humanos , Retalhos Cirúrgicos , Orelha Externa/cirurgia , Pavilhão Auricular/cirurgia , Cartilagem
16.
ChemistryOpen ; 13(4): e202300173, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38085118

RESUMO

The decomposition of methane has been chosen as an alternative method for producing hydrogen. In this study, 20 % Fe was used as the active metal part of the catalyst. To better comprehend the impact of the supporting catalytic properties, alumina and titania-alumina composite were investigated as supports. Iron-based catalysts were prepared by impregnation method and then calcined at different temperatures (300 °C, 500 °C, and 800 °C). The catalysts were examined at 800 °C under atmospheric pressure with a 15 mL/min total flow rate and 2 : 1 CH4 to N2 feed ratio. The textural and morphological characteristics of the fresh calcined and spent catalysts were investigated. The catalytic activity and stability data demonstrated that Fe supported over TiO2-Al2O3 calcined at 500 °C performed the best of all evaluated catalysts with a more than 80 % hydrogen yield. The Raman spectra result showed that graphitic carbon was produced for all used titanium dioxide catalysts. Moreover, according to transmission electron microscopy (TEM) results, the carbon deposited on the catalysts' surface is carbon nanotubes (CNT).

17.
Chemosphere ; 349: 140838, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38043612

RESUMO

In this comprehensive study, Ce-doped ZnO nanostructures were hydrothermally synthesized with varying Ce concentrations (0.5%, 1.0%, 1.5%, and 2.0%) to explore their gas-sensing capabilities, particularly towards NO2. Structural characterization revealed that as Ce doping increased, crystal size exhibited a slight increment while band gap energies decreased. Notably, the 0.5% Ce-doped ZnO nanostructure demonstrated the highest NO2 gas response of 8.6, underscoring the significance of a delicate balance between crystal size and band gap energy for optimal sensing performance. The selectivity of the 0.5% Ce-doped ZnO nanostructures to NO2 over other gases like H2, acetone, NH3, and CO at a concentration of 100 ppm and an optimized temperature of 250 °C was exceptional, highlighting its discriminatory prowess even in the presence of potential interfering gases. Furthermore, the sensor displayed reliability and reversibility during five consecutive tests, showcasing consistent performance. Long-term stability testing over 30 days revealed that the gas response remained almost constant, indicating the sensor's remarkable durability. In addition to its robustness against humidity variations, maintaining effectiveness even at 41% humidity, the sensor exhibited impressive response and recovery times. While the response time was swift at 11.8 s, the recovery time was slightly prolonged at 56.3 s due to the strong adsorption of NO2 molecules onto the sensing material hindering the desorption process. The study revealed the intricate connection between Ce-doping levels, structure, and gas-sensing. It highlighted the 0.5% Ce-doped ZnO nanostructure as a highly selective, reliable, and durable NO2 gas sensor, with implications for future environmental monitoring and safety.


Assuntos
Dióxido de Nitrogênio , Óxido de Zinco , Reprodutibilidade dos Testes , Acetona , Gases
18.
Chemosphere ; 349: 140657, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38000555

RESUMO

The development of advanced materials for energy storage and gas sensing applications has gained significant attention in recent years. In this study, we synthesized and characterized PANI@MnO2@rGO ternary nanocomposites (NCs) to explore their potential in supercapacitors and gas sensing devices. The ternary NCs were synthesized through a multi-step process involving the hydrothermal synthesis of MnO2 nanoparticles, preparation of PANI@rGO composites and the assembly to the ternary PANI@MnO2@rGO ternary NCs. The structural, morphological, and compositional characteristics of the materials were thoroughly analyzed using techniques such as XRD, FESEM, TEM, FTIR, and Raman spectroscopy. In the realm of gas sensing, the ternary NCs exhibited excellent performance as NH3 gas sensors. The optimized operating temperature of 100 °C yielded a peak response of 15.56 towards 50 ppm NH3. The nanocomposites demonstrated fast response and recovery times of 6 s and 10 s, respectively, and displayed remarkable selectivity for NH3 gas over other tested gases. For supercapacitor applications, the electrochemical performance of the ternary NCs was evaluated using cyclic voltammetry and galvanostatic charge-discharge techniques. The composites exhibited pseudocapacitive behavior, with the capacitance reaching up to 185 F/g at 1 A/g and excellent capacitance retention of approximately 88.54% over 4000 charge-discharge cycles. The unique combination of rGO, PANI, and MnO2 nanoparticles in these ternary NCs offer synergistic advantages, showcasing their potential to address challenges in energy storage and gas sensing technologies.


Assuntos
Compostos de Manganês , Nanocompostos , Óxidos , Fenômenos Físicos , Gases
19.
Photochem Photobiol ; 2023 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-38088069

RESUMO

The photocatalytic oxidation and generation/regeneration of amines to imines and leucodopaminechrome (LDC)/NADH are subjects of intense interest in contemporary research. Imines serve as crucial intermediates for the synthesis of solar fuels, fine chemicals, agricultural chemicals, and pharmaceuticals. While significant progress has been made in developing efficient processes for the oxidation and generation/regeneration of secondary amines, the oxidation of primary amines has received comparatively less attention until recently. This discrepancy can be attributed to the high reactivity of imines generated from primary amines, which are prone to dehydrogenation into nitriles. In this study, we present the synthesis and characterization of a novel polymer-based photocatalyst, denoted as PMMA-DNH, designed for solar light-harvesting applications. PMMA-DNH incorporates the light-harvesting molecule dinitrophenyl hydrazine (DNH) at varying concentrations (5%, 10%, 20%, 30%, and 40%). Leveraging its high molar extinction coefficient and slow charge recombination, the 30% DNH-incorporated PMMA photocatalyst proves to be particularly efficient. This photocatalytic system demonstrates exceptional yields (96.5%) in imine production and high generation/regeneration rates for LDC/NADH (65.27%/78.77%). The research presented herein emphasizes the development and application of a newly engineered polymer-based photocatalyst, which holds significant promise for direct solar-assisted chemical synthesis in diverse commercial applications.

20.
Nanomaterials (Basel) ; 13(23)2023 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-38063681

RESUMO

5Ni/MgO and 5Ni/γAl2O3 are pronounced in the line of cheap catalyst systems for the dry reforming of methane. However, the lower reducibility of 5Ni/MgO and the significant coke deposition over 5Ni/γAl2O3 limit their applicability as potential DRM catalysts. The mixing capacity of MgO and Al2O3 may overcome these limitations without increasing the catalyst cost. Herein, a 5Ni/xMg(100 - x)Al (x = 0, 20, 30, 60, 70, and 100 wt. %) catalyst system is prepared, investigated, and characterized with X-ray diffraction, surface area and porosity measurements, H2-temperature programmed reduction, UV-Vis-IR spectroscopy, Raman spectroscopy, thermogravimetry, and transmission electron microscopy. Upon the addition of 20 wt. % MgO into the Al2O3 support, 5Ni/20Mg80Al is expanded and carries both stable Ni sites (derived through the reduction of NiAl2O4) and a variety of CO2-interacting species. CH4 decomposition at Ni sites and the potential oxidation of carbon deposits by CO2-interacting species over 5Ni/20Mg80Al results in a higher 61% H2-yield (against ~55% H2-yield over 5Ni/γAl2O3) with an excellent carbon-resistant property. In the major magnesia support system, the 5Ni/60Mg40Al catalyst carries stable Ni sites derived from MgNiO2 and "strongly interacted NiO-species". The H2-yield over the 5Ni/60Mg40Al catalyst moves to 71%, even against a high coke deposition, indicating fine tuning between the carbon formation and diffusion rates. Ni dispersed over magnesia-alumina with weight ratios of 7/3 and 3/7 exhibit good resistance to coke. Weight ratios of 2/8 and 7/3 contain an adequate amount of reducible and CO2-interactive species responsible for producing over 60% of H2-yield. Weight ratio 6/4 has a proper coke diffusion mechanism in addition to achieving a maximum of 71% H2-yield.

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