Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 32
Filtrar
1.
J Am Chem Soc ; 2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38869376

RESUMO

Photothermal hydrogenation of carbon dioxide (CO2) into value-added products is an ideal solution for addressing the energy crisis and mitigating CO2 emissions. However, achieving high product selectivity remains challenging due to the simultaneous occurrence of numerous competing intermediate reactions during CO2 hydrogenation. We present a novel approach featuring isolated single-atom nickel (Ni) anchored onto indium oxide (In2O3) nanocrystals, serving as an effective photothermal catalyst for CO2 hydrogenation into methane (CH4) with a remarkable near-unity (∼99%) selectivity. Experiments and theoretical simulations have confirmed that isolated Ni sites on the In2O3 surface can effectively stabilize the intermediate products of the CO2 hydrogenation reaction and reduce the transition state energy barrier, thereby changing the reaction path to achieve ultrahigh selective methanation. This study provides comprehensive insights into the design of single-atom catalysts for the highly selective photothermal catalytic hydrogenation of CO2 to methane.

2.
Small ; 19(25): e2208179, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36935369

RESUMO

The realization of solar-light-driven CO2  reduction reactions (CO2 RR) is essential for the commercial development of renewable energy modules and the reduction of global CO2 emissions. Combining experimental measurements and theoretical calculations, to introduce boron dopants and nitrogen defects in graphitic carbon nitride (g-C3 N4 ), sodium borohydride is simply calcined with the mixture of g-C3 N4 (CN), followed by the introduction of ultrathin Co phthalocyanine through phosphate groups. By strengthening H-bonding interactions, the resultant CoPc/P-BNDCN nanocomposite showed excellent photocatalytic CO2 reduction activity, releasing 197.76 and 130.32 µmol h-1  g-1 CO and CH4 , respectively, and conveying an unprecedented 10-26-time improvement under visible-light irradiation. The substantial tuning is performed towards the conduction and valance band locations by B-dopants and N-defects to modulate the band structure for significantly accelerated CO2 RR. Through the use of ultrathin metal phthalocyanine assemblies that have a lot of single-atom sites, this work demonstrates a sustainable approach for achieving effective photocatalytic CO2 activation. More importantly, the excellent photoactivity is attributed to the fast charge separation via Z-scheme transfer mechanism formed by the universally facile strategy of dimension-matched ultrathin (≈4 nm) metal phthalocyanine-assisted nanocomposites.

3.
Angew Chem Int Ed Engl ; 62(48): e202305385, 2023 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-37530435

RESUMO

Transition metal oxides (TMOs) were one of the first photocatalysts used to produce hydrogen from water using solar energy. Despite the emergence of many other genres of photocatalysts over the years, TMO photocatalysts remain dominant due to their easy synthesis and unique physicochemical properties. Various strategies have been developed to enhance the photocatalytic activity of TMOs, but the solar-to-hydrogen (STH) conversion efficiency of TMO photocatalysts is still very low (<2 %), which is far below the targeted STH of 10 % for commercial viability. This article provides a comprehensive analysis of several widely used strategies, including oxygen defects control, doping, establishing interfacial junctions, and phase-facet-morphology engineering, that have been adopted to improve TMO photocatalysts. By critically evaluating these strategies and providing a roadmap for future research directions, this article serves as a valuable resource for researchers, students, and professionals seeking to develop efficient energy materials for green energy solutions.

6.
Environ Sci Technol ; 50(24): 13600-13610, 2016 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-27993053

RESUMO

In this work, TiO2-coupled N-doped porous perovskite-type LaFeO3 nanocomposites as highly efficient, cheap, stable, and visible-light photocatalysts have successfully been prepared via wet chemical processes. It is shown that the amount-optimized nanocomposite exhibits exceptional visible-light photocatalytic activities for 2,4-dichlorophenol (2,4-DCP) degradation by ∼3-time enhancement and for CO2 conversion to fuels by ∼4-time enhancement, compared to the resulting porous LaFeO3 with rather high photoactivity due to its large surface area. It is clearly demonstrated, by means of various experimental data, especially for the ·OH amount evaluation, that the obviously enhanced photoactivities are attributed to the increased specific surface area by introducing pores, to the extended visible-light absorption by doping N to create surface states, and to the promoted charge transfer and separation by coupling TiO2. Moreover, it is confirmed from radical trapping experiments that the photogenerated holes are the predominant oxidants in the photocatalytic degradation of 2,4-DCP. Furthermore, a possible photocatalytic degradation mechanism for 2,4-DCP is proposed mainly based on the resultant crucial intermediate, 2-chlorosuccinic acid with m/z = 153, that readily transform into CO2 and H2O. This work opens up a new feasible route to synthesize visible-light-responsive high-activity perovskite-type nanophotocatalysts for efficient environmental remediation and energy production.


Assuntos
Luz , Nanocompostos/química , Catálise , Porosidade
8.
Anim Biosci ; 37(3): 500-508, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36915928

RESUMO

OBJECTIVE: Due to current selection practices for increased egg production and peak persistency, the production profile, age at maturity, and body weight criteria for commercial layers are constantly changing. Body weight and age at the time of photostimulation will thus always be the factors that need to be adequately addressed among various production systems. The current study was carried out to determine the effects of pullets' body weight (low, medium, and heavy) on their performance, welfare, physiological response, and hormonal profile. METHODS: With regard to live weight, 150 16-week-old pullets were divided into three groups using a completely randomized design (CRD) and held until the 50th week. One-way analysis of variance was used to evaluate the data under the CRD, and the least significant difference test was used to distinguish between treatment means. RESULTS: In comparison to the medium and light birds, the heavy birds had higher body weight at maturity, an earlier age at maturity, and higher egg weight, eggshell weight, eggshell thickness, egg yolk index, breaking strength, egg surface area, egg shape index, egg volume, and hormonal profile except corticosterone. However, the medium and light birds had lower feed consumption rates per dozen eggs and per kilogram of egg mass than the heavy birds. Light birds showed greater body weight gain, egg production, and egg specific gravity than the other categories. At 20 weeks of age, physiological response, welfare aspects, and catalase were non-significant; however, at 50 weeks of age, all these factors-aside from catalase-were extremely significant. CONCLUSION: The findings of this study indicate that layers can function at lower body weights during photostimulation; hence, dietary regimens that result in lighter pullets may be preferable. Additionally, the welfare of the birds was not compromised by the lighter weight group.

9.
ACS Nano ; 18(1): 288-298, 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-37955363

RESUMO

Modulation of the local electronic structure of isolated coordination structures plays a critical role in electrocatalysis yet remains a grand challenge. Herein, we have achieved electron perturbation for the isolated iron coordination structure via tuning the iron spin state from a high spin state (FeN4) to a medium state (FeN2B2). The transition of spin polarization facilitates electron penetration into the antibonding π orbitals of nitrogen and effectively activates nitrogen molecules, thereby achieving an ammonia yield of 115 µg h-1 mg-1cat. and a Faradaic efficiency of 24.8%. In situ spectroscopic studies and theoretical calculations indicate that boron coordinate sites, as electron acceptors, can regulate the adsorption energy of NxHy intermediates on the Fe center. FeN2B2 sites favor the NNH* intermediate formation and reduce the energy barrier of rate-determining steps, thus accounting for excellent nitrogen fixation performance. Our strategy provides an effective approach for designing efficient electrocatalysts via precise electronic perturbation.

10.
J Colloid Interface Sci ; 672: 370-382, 2024 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-38850864

RESUMO

Improving ligand-to-active metal charge transfer (LAMCT) by finely tuning the organic ligand is a decisive strategy to enhance charge transfer in metal organic frameworks (MOFs)-based catalysts. However, in most MOFs loaded with active metal catalysts, electron transmission encounters massive obstacle at the interface between the two constituents owing to poor LAMCT. Herein, amines (-NH2) functionalized MOFs (NH2-MIL-101(Cr)) encapsulated active metal Pt nanoclusters (NCs) catalysts are synthesized by the polyol reduction method and utilized for the photoreduction of CO2. Surprisingly, the introduction of -NH2 (electron donating) groups within the matrix of MIL-101(Cr) improved the electron migration through the LAMCT process, fostering a synergistic interaction with Pt. The combined experimental analysis exposed the high number of metallic Pt (Pt0) in Pt@NH2-MIL-101(Cr) catalyst through seamless electron shuttling from N of -NH2 group to excited Pt generating versatile hybrid Pt-N catalytic centres. Consequently, these versatile hybrid catalytic centres act as electro-nucleophilic centres, which enable the efficient and selective conversion of CO bond in CO2 to harvest CH4 (131.0 µmol.g-1) and maintain excellent stability and selectivity for consecutive five rounds, superior to Pt@MIL-101(Cr) and most reported catalysts. Our study verified that the precise tuning of organic ligands in MOFs immensely improves the surface-active centres, electron migration, and catalytic selectivity of the excited Pt NCs catalysts encaged inside MOFs through an improved LAMCT pathway.

11.
J Colloid Interface Sci ; 665: 500-509, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38547631

RESUMO

Constructing a heterojunction by combining two semiconductors with similar band structures is a successful approach to obtaining photocatalysts with high efficiency. Herein, a CuPc/DR-MoS2 heterojunction involving copper phthalocyanine (CuPc) and molybdenum disulfide with S-rich vacancies (13.66%) is successfully prepared by the facile hydrothermal method. Experimental results and theoretical calculations firmly demonstrated that photoelectrons exhibit an S-scheme charge transfer mechanism in the CuPc/DR-MoS2 heterojunction. The S-scheme heterojunction system has proven significant advantages in promoting the charge separation and transfer of photogenerated carriers, enhancing visible-light responsiveness, and achieving robust photoredox capability. As a result, the optimized 3CuPc/DR-MoS2 S-scheme heterojunction exhibits photocatalytic yields of CO and CH4 at 200 and 111.6 µmol g-1h-1, respectively. These values are four times and 4.5 times greater than the photocatalytic yields of pure DR-MoS2. This study offers novel perspectives on the advancement of innovative and highly effective heterojunction photocatalysts.

12.
J Bronchology Interv Pulmonol ; 31(1): 63-69, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-37246305

RESUMO

BACKGROUND: Benign airway stenosis (BAS) represents a significant burden on patients, providers, and healthcare systems. Spray cryotherapy (SCT) has been proposed as an adjunctive treatment to reduce BAS recurrence. We sought to examine safety and practice variations of the latest SCT system when used for BAS. METHODS: We conducted a retrospective multicenter cohort study in seven academic institutions within the Interventional Pulmonary Outcomes Group. All patients who underwent at least one SCT session with a diagnosis of BAS at the time of procedure at these institutions were included. Demographics, procedure characteristics, and adverse events were captured through each center's procedural database and electronic health record. RESULTS: A total of 102 patients underwent 165 procedures involving SCT from 2013 to 2022. The most frequent etiology of BAS was iatrogenic (n = 36, 35%). In most cases, SCT was used prior to other standard BAS interventions (n = 125; 75%). The most frequent SCT actuation time per cycle was five seconds. Pneumothorax complicated four procedures, requiring tube thoracostomy in two. Significant post-SCT hypoxemia was noted in one case, with recovery by case conclusion and no long-term effects. There were no instances of air embolism, hemodynamic compromise, or procedural or in-hospital mortality. CONCLUSION: SCT as an adjunctive treatment for BAS was associated with a low rate of complications in this retrospective multicenter cohort study. SCT-related procedural aspects varied widely in examined cases, including actuation duration, number of actuations, and timing of actuations relative to other interventions.


Assuntos
Criocirurgia , Crioterapia , Humanos , Estudos Retrospectivos , Estudos de Coortes , Constrição Patológica/etiologia , Crioterapia/efeitos adversos , Criocirurgia/efeitos adversos
13.
Nanoscale ; 16(9): 4352-4377, 2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38275275

RESUMO

Semiconductor-based photocatalysis has attracted significant interest due to its capacity to directly exploit solar energy and generate solar fuels, including water splitting, CO2 reduction, pollutant degradation, and bacterial inactivation. However, achieving the maximum efficiency in photocatalytic processes remains a challenge owing to the speedy recombination of electron-hole pairs and the limited use of light. Therefore, significant endeavours have been devoted to addressing these issues. Specifically, well-designed heterojunction photocatalysts have been demonstrated to exhibit enhanced photocatalytic activity through the physical distancing of electron-hole pairs generated during the photocatalytic process. In this review, we provide a systematic discussion ranging from fundamental mechanisms to material strategies, focusing on TiO2-based heterojunction photocatalysts. Current efforts are focused on developing heterojunction photocatalysts based on TiO2 for a variety of photocatalytic applications, and these projects are explained and assessed. Finally, we offer a concise summary of the main insights and challenges in the utilization of TiO2-based heterojunction photocatalysts for photocatalysis. We expect that this review will serve as a valuable resource to improve the efficiency of TiO2-based heterojunctions for energy generation and environmental remediation.

14.
J Colloid Interface Sci ; 663: 31-42, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38387184

RESUMO

The construction of van der Waals (vdW) heterojunctions is a key approach for efficient and stable photocatalysts, attracting marvellous attention due to their capacity to enhance interfacial charge separation/transfer and offer reactive sites. However, when a vdW heterojunction is made through an ex-situ assembly, electron transmission faces notable obstacles at the components interface due to the substantial spacing and potential barrier. Herein, we present a novel strategy to address this challenge via wet chemistry by synthesizing a functionalized graphene-modulated Z-scheme vdW heterojunction of zinc phthalocyanine/tungsten trioxide (xZnPc/yG-WO3). The functionalized G-modulation forms an electron "bridge" across the ZnPc/WO3 interface to improve electron transfer, get rid of barriers, and ultimately facilitating the optimal transfer of excited photoelectrons from WO3 to ZnPc. The Zn2+ in ZnPc picks up these excited photoelectrons, turning CO2 into CO/CH4 (42/22 µmol.g-1.h-1) to deliver 17-times better efficiency than pure WO3. Therefore, the introduction of a molecular "bridge" as a means to establish an electron transfer conduit represents an innovative approach to fabricate efficient photocatalysts designed for the conversion of CO2 into valued yields.

15.
Adv Mater ; 35(38): e2303047, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37363951

RESUMO

Constructing Van der Waals heterojunction is a crucial strategy to achieve excellent photocatalytic activity. However, in most Van der Waals heterojunctions synthesized by ex situ assembly, electron transfer encounters huge hindrances at the interface between the two components due to the large spacing and potential barrier. Herein, a phosphate-bridged Van der Waals heterojunction of cobalt phthalocyanine (CoPc)/tungsten disulfide (WS2 ) bridged by phosphate (xCoPc-nPO4 - -WS2 ) is designed and prepared by the traditional wet chemistry method. By introducing a small phosphate molecule into the interface of CoPc and WS2 , creates an electron "bridge", resulting in a compact combination and eliminating the space barrier. Therefore, the phosphate (PO4 - ) bridge can serve as an efficient electron transfer channel in heterojunction and can efficiently transmit photoelectrons from WS2 to CoPc under excited states. These excited photoelectrons are captured by the catalytic central Co2+ in CoPc and subsequently convert CO2 molecules into CO and CH4 products, achieving 17-fold enhancement on the 3CoPc-0.6PO4 - -WS2 sample compared to that of pure WS2 . Introducing a small molecule "bridge" to create an electron transfer channel provides a new perspective in designing efficient photocatalysts for photocatalytic CO2 reduction into valuable products.

16.
Environ Sci Pollut Res Int ; 29(22): 32594-32604, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35195862

RESUMO

Genetically, modern broilers are fast-growing birds which attain the market age at the age of 5 weeks. To maintain optimum production, antibiotics have been commonly included in the diets as growth promoters. However, due to the increase in antimicrobial resistance, their uses have been banned worldwide. To keep the optimum level of production and health in broiler industry, the use of alternative growth promoters such as probiotics, prebiotics, enzymes, and organic acids has been proposed. Chemically, organic acids are weak acids and only partially dissociate. They are considered safe and have been used for preservation of food for centuries. Nowadays, organic acids have been reported for antibacterial, immune potentiating, and growth promoters in broilers. In this review, the effects of dietary inclusion of organic acids on growth, nutrient digestibility, intestinal integrity, immune system, and antibacterial activity in broilers are discussed.


Assuntos
Fenômenos Fisiológicos da Nutrição Animal , Galinhas , Ácidos/farmacologia , Ração Animal/análise , Animais , Antibacterianos/farmacologia , Dieta/veterinária , Suplementos Nutricionais , Digestão , Compostos Orgânicos
17.
Adv Sci (Weinh) ; 9(2): e2102530, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34859614

RESUMO

Artificial Z-scheme, a tandem structure with two-step excitation process, has gained significant attention in energy production and environmental remediation. By effectively connecting and matching the band-gaps of two different photosystems, it is significant to utilize more photons for excellent photoactivity. Herein, a novel one-photon (same energy-two-photon) Z-scheme system is constructed between rGO modified boron-nitrogen co-doped-WO3 , and coupled CdSe quantum dots-(QDs). The coctalyst-0.5%Rhx Cr2 O3 (0.5RCr) modified amount-optimized sample 6%CdSe/1%rGO3%BN-WO3 revealed an unprecedented visible-light driven overall-water-splitting to produce ≈51 µmol h-1 g-1 H2 and 25.5 µmol h-1 g-1 O2 , and it remained unchanged for 5 runs in 30 h. This superior performance is ascribed to the one-photon Z-scheme, which simultaneously stimulates a two photocatalysts system, and enhanced charge separation as revealed by various spectroscopy techniques. The density-functional theory is further utilized to understand the origin of this performance enhancement. This work provides a feasible strategy for constructing an efficient one-photon Z-scheme for practical applications.

18.
Perm J ; 252021 12 10.
Artigo em Inglês | MEDLINE | ID: mdl-35348081

RESUMO

INTRODUCTION: Breast cancer is the most common malignancy affecting women in US today. Radiotherapy used after breast-conserving surgery has been shown to decrease local recurrence while minimizing side effects. Peripheral neuropathy remains a common and well-known complication of radiotherapy for breast cancer; however, it is rarely associated with phrenic nerve palsy after treatment of breast cancer. CASE PRESENTATION: We describe a 66-year-old woman with a significant past medical history of chronic obstructive pulmonary disease and asthma who presented with hypoxia after completing radiotherapy for breast cancer. After ruling out other causes of hypoxemia, the patient was diagnosed with diaphragmatic dysfunction, likely caused by phrenic nerve palsy resulting from radiotherapy-induced neuropathy after treatment of breast cancer. CONCLUSION: This case is the first reported incidence of phrenic nerve palsy resulting from radiotherapy for breast cancer.


Assuntos
Neoplasias da Mama , Doenças do Sistema Nervoso Periférico , Idoso , Neoplasias da Mama/radioterapia , Neoplasias da Mama/cirurgia , Feminino , Humanos , Mastectomia Segmentar , Paralisia/etiologia , Paralisia/cirurgia , Doenças do Sistema Nervoso Periférico/etiologia , Doenças do Sistema Nervoso Periférico/cirurgia , Nervo Frênico
19.
BMJ Case Rep ; 14(4)2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33795283

RESUMO

A 59-year-old woman presented to the emergency department with shortness of breath. She had significant oropharyngeal swelling obstructing her upper respiratory tract. A diagnosis of laryngeal myxoedema was made, which was attributed to severe hypothyroidism. She required invasive ventilation and subsequently a tracheostomy. She was treated with levothyroxine and hydrocortisone. She completely recovered with this therapy. In this review, we will discuss similar cases and different therapeutic options. This case also highlights the fact that establishing a diagnosis of laryngeal myxoedema, a condition that can potentially have lethal outcomes and can be challenging.


Assuntos
Hipotireoidismo , Laringe , Mixedema , Feminino , Humanos , Hipotireoidismo/complicações , Hipotireoidismo/tratamento farmacológico , Laringe/diagnóstico por imagem , Pessoa de Meia-Idade , Mixedema/complicações , Mixedema/diagnóstico , Mixedema/tratamento farmacológico , Tiroxina/uso terapêutico , Traqueostomia
20.
Case Rep Crit Care ; 2021: 8850116, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33688441

RESUMO

Dexmedetomidine is an α2-adrenergic used as an adjunct therapy for sedation in the intensive care unit. While it is known to cause polyuria exclusively in perioperative conditions, not many cases are known in the intensive care unit, thus making the diagnosis challenging. We present the case of a 61-year-old male who had developed polyuria secondary to central diabetes insipidus after receiving dexmedetomidine intravenous infusion in the medical ICU. Increased awareness of this uncommon side effect of dexmedetomidine will help clinicians recognize and address it early.

SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa