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1.
Voluntas ; 33(6): 1235-1244, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35233150

RESUMO

Within-study comparisons (WSCs) compare quasi-experimental results to an experimental benchmark and assess the extent to which quasi-experiments (QEs) sacrifice internal validity for external validity. WSCs inform decisions about when to use experiments or QEs, as well as methodological decisions (e.g., covariate selection) about how to implement QEs when they are necessary or preferred. We review the methodological literature on WSCs and present the findings from a WSC of a school voucher program as an example of the use of WSCs to inform policy debates involving the third sector. Prior literature and our results suggest that QE evaluations of third-sector institutions can produce low levels of bias, but only if analytic models include key proxy variables for voluntary self-selection into programs.

2.
Int J Mol Sci ; 22(12)2021 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-34207150

RESUMO

P2X7 receptors (P2X7) are cationic channels involved in many diseases. Following their activation by extracellular ATP, distinct signaling pathways are triggered, which lead to various physiological responses such as the secretion of pro-inflammatory cytokines or the modulation of cell death. P2X7 also exhibit unique behaviors, such as "macropore" formation, which corresponds to enhanced large molecule cell membrane permeability and current facilitation, which is caused by prolonged activation. These two phenomena have often been confounded but, thus far, no clear mechanisms have been resolved. Here, by combining different approaches including whole-cell and single-channel recordings, pharmacological and biochemical assays, CRISPR/Cas9 technology and cell imaging, we provide evidence that current facilitation and macropore formation involve functional complexes comprised of P2X7 and TMEM16, a family of Ca2+-activated ion channel/scramblases. We found that current facilitation results in an increase of functional complex-embedded P2X7 open probability, a result that is recapitulated by plasma membrane cholesterol depletion. We further show that macropore formation entails two distinct large molecule permeation components, one of which requires functional complexes featuring TMEM16F subtype, the other likely being direct permeation through the P2X7 pore itself. Such functional complexes can be considered to represent a regulatory hub that may orchestrate distinct P2X7 functionalities.


Assuntos
Anoctaminas/metabolismo , Receptores Purinérgicos P2X7/metabolismo , Trifosfato de Adenosina/metabolismo , Algoritmos , Animais , Anoctaminas/química , Sistemas CRISPR-Cas , Membrana Celular/metabolismo , Permeabilidade da Membrana Celular , Colesterol/metabolismo , Células HEK293 , Humanos , Imuno-Histoquímica , Modelos Biológicos , Oócitos , Receptores Purinérgicos P2X7/química
3.
Health Care Manage Rev ; 46(1): 12-24, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-31116121

RESUMO

BACKGROUND: Life cycle assessment (LCA) is an environmental accounting tool aimed at determining environmental impacts of products, processes, or organizational activities over the entire life cycle. Although this technique already provides decision-makers in other sectors with valuable information, its application in the health care setting has not yet been examined. PURPOSE: The aim of this study was to provide a comprehensive overview of scientific research on the application of LCA in hospitals and its contribution to management decision-making. METHOD: We perform a systematic literature review by searching a range of databases with synonyms of "LCA" in combination with the term "hospital" in order to identify peer-reviewed studies. The final sample of 43 studies were then subjected to a content analysis. RESULTS: We categorize existing research and show that single and multi-indicator LCA approaches are used to examine several products and processes in hospitals. The various approaches are favored by different scientific communities. Whereas researchers from environmental sciences perform complex multi-indicator LCA studies, researchers from health care sciences focus on footprints. The studies compare alternatives and identify environmental impacts and harmful hotspots. PRACTICE IMPLICATIONS: LCA results can support health care managers' traditional decision-making by providing environmental information. With this additional information regarding the environmental impacts of products and processes, managers can implement organizational changes to improve their environmental performance. Furthermore, they can influence upstream and downstream activities. However, we recommend more transdisciplinary cooperation for LCA studies and to place more focus on actionable recommendations when publishing the results.


Assuntos
Conservação dos Recursos Naturais , Hospitais , Animais , Humanos , Estágios do Ciclo de Vida
4.
Phys Chem Chem Phys ; 21(35): 19065-19075, 2019 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-31410424

RESUMO

The catalytic properties of zeolites are intimately linked to the distribution and relative positions of Al atoms and defects in the pore network. However, characterizing this distribution is challenging, in particular when different local Al arrangements are considered. In this contribution we use a combination of first principles calculations and experimental measurements to develop a model for the Al-distribution in protonated SSZ-13. We furthermore apply this model to understand trends in OH-IR, 27Al-NMR and 29Si-NMR spectra. We use a Boltzmann distribution to predict the proton position for a given local Al configuration and show that for each configuration several H positions are occupied. Therefore a multi-peak spectrum in OH-IR vibrational spectroscopy is observed for all Al configurations, which is in line with experimentally measured spectra for zeolites at different Si/Al ratios. From NMR spectroscopy we find that the proton position leads to significant shifts in 27Al-NMR and 29Si-NMR spectra due to the modification of the local strain, which is lost when a uniform background charge is introduced. These findings are supported by experimental measurements. Finally we discuss the shortcomings of the presented model in terms of unit cell size and the impact of adjacent unit cells.

5.
J Ultrasound Med ; 38(5): 1167-1177, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30218456

RESUMO

OBJECTIVES: Intraventricular pressure (IVP) is one of the most important measurements for evaluating cardiac function, but this measurement is not currently easily assessable in the clinic. The primary reason for this is the absence of a noninvasive technique for measuring IVP. In this study, we investigate the relationship between IVP and dynamic myocardial stiffness measured by shear wave elasticity imaging (SWEI) and assess the feasibility of measuring IVP using SWEI. METHODS: In 8 isolated working rabbit hearts, IVP was recorded in the left ventricle using a pressure catheter. Simultaneously, myocardial stiffness was recorded by SWEI. Using the peak values for IVP and SWEI measured stiffness, SWEI measurements were calibrated and converted to IVP. RESULTS: A linear relationship with zero intercept was observed between IVP and SWEI, with the average slope of 0.318 kPa/mm Hg, R2 = 0.89. Using one point on the IVP/SWEI curve, SWEI measurements were converted to IVP. Estimated pressure using SWEI and IVP were linearly correlated with the slope of 0.95, R2 = 0.88 (mean end diastolic pressure by pressure catheter = 12.716 mm Hg and by SWEI=14.726 mm Hg), indicating the near equivalence of the 2 measurements. CONCLUSION: We have shown that SWEI measurements are linearly related to IVP; therefore, pressure-based indices could potentially be derived from SWEI ultrasound elastography. The feasibility of using SWEI to estimate IVP with a single point calibration was also shown in this study.


Assuntos
Técnicas de Imagem por Elasticidade/métodos , Coração/diagnóstico por imagem , Coração/fisiologia , Pressão Ventricular/fisiologia , Animais , Estudos de Viabilidade , Coração/fisiopatologia , Modelos Animais , Coelhos
6.
Angew Chem Int Ed Engl ; 58(39): 13989-13996, 2019 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-31328855

RESUMO

Selective hydrogenation of CO2 into methanol is a key sustainable technology, where Cu/Al2 O3 prepared by surface organometallic chemistry displays high activity towards CO2 hydrogenation compared to Cu/SiO2 , yielding CH3 OH, dimethyl ether (DME), and CO. CH3 OH formation rate increases due to the metal-oxide interface and involves formate intermediates according to advanced spectroscopy and DFT calculations. Al2 O3 promotes the subsequent conversion of CH3 OH to DME, showing bifunctional catalysis, but also increases the rate of CO formation. The latter takes place 1) directly by activation of CO2 at the metal-oxide interface, and 2) indirectly by the conversion of formate surface species and CH3 OH to methyl formate, which is further decomposed into CH3 OH and CO. This study shows how Al2 O3 , a Lewis acidic and non-reducible support, can promote CO2 hydrogenation by enabling multiple competitive reaction pathways on the oxide and metal-oxide interface.

7.
J Am Chem Soc ; 140(33): 10530-10535, 2018 08 22.
Artigo em Inglês | MEDLINE | ID: mdl-30028948

RESUMO

Copper nanoparticles supported on zirconia (Cu/ZrO2) or related supported oxides (Cu/ZrO2/SiO2) show promising activity and selectivity for the hydrogenation of CO2 to CH3OH. However, the role of the support remains controversial because most spectroscopic techniques provide information dominated by the bulk, making interpretation and formulation of structure-activity relationships challenging. In order to understand the role of the support and in particular of the Zr surface species at a molecular level, a surface organometallic chemistry approach has been used to tailor a silica support containing isolated Zr(IV) surface sites, on which copper nanoparticles (∼3 nm) are generated. These supported Cu nanoparticles exhibit increased CH3OH activity and selectivity compared to those supported on SiO2, reaching catalytic performances comparable to those of the corresponding Cu/ZrO2. Ex situ and in situ X-ray absorption spectroscopy reveals that the Zr sites on silica remain isolated and in their +4 oxidation state, while ex situ solid-state nuclear magnetic resonance spectroscopy and catalytic performances show that similar mechanisms are involved with the single-site support and ZrO2. These observations imply that Zr(IV) surface sites at the periphery of Cu particles are responsible for promoting CH3OH formation on Cu-Zr-based catalysts and provide a guideline to develop selective CH3OH synthesis catalysts.

8.
J Food Sci Technol ; 55(8): 3077-3084, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30065417

RESUMO

Reduced elasticity and high stickiness of gluten-free bread doughs are major issues regarding the industrial breadmaking process. In this work, we compared traditional batch mixing with a revised continuous extrusion process and extensively study the rheological properties of both doughs. Shear viscosities were measured offline with a capillary rheometer and inline at the extruder die over a large range of apparent shear rates. Data were corrected for entrance effects, wall slip and non-Newtonian flow behaviour. Good agreement between inline and offline measured viscosities were supplemented by amplitude and frequency sweep tests. The results highlight that this extrusion process fostered the production of gluten-free bread dough. We demonstrated that extrusion processing support the combined mixing, kneading, and moulding of gluten-free dough in one single unit. This fundamental study linked physical dough characterization with applied engineering and yielded the understanding and processing of corresponding products.

9.
J Cardiovasc Electrophysiol ; 26(9): 1009-1018, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25970142

RESUMO

INTRODUCTION: Elastography imaging can provide radiofrequency ablation (RFA) lesion assessment due to tissue stiffening at the ablation site. An important aspect of assessment is the spatial and temporal stability of the region of stiffness increase in the peri-ablation period. The aim of this study was to use 2 ultrasound-based elastography techniques, shear wave elasticity imaging (SWEI) and acoustic radiation force impulse (ARFI) imaging, to monitor the evolution of tissue stiffness at ablation sites in the 30 minutes following lesion creation. METHODS AND RESULTS: In 6 canine subjects, SWEI measurements and 2-D ARFI images were acquired at 6 ventricular endocardial RFA sites before, during, and for 30 minutes postablation. An immediate increase in tissue stiffness was detected during RFA, and the area of the postablation region of stiffness increase (RoSI) as well as the relative stiffness at the RoSI center was stable approximately 2 minutes after ablation. Of note is the observation that relative stiffness in the region adjacent to the RoSI increased slightly during the first 15 minutes, consistent with local fluid displacement or edema. The magnitude of this increase, ∼0.5-fold from baseline, was significantly less than the magnitude of the stiffness increase directly inside the RoSI, which was greater than 3-fold from baseline. CONCLUSIONS: Ultrasound-based SWEI and ARFI imaging detected an immediate increase in tissue stiffness during RFA, and the stability and magnitude of the stiffness change suggest that consistent elasticity-based lesion assessment is possible 2 minutes after and for at least 30 minutes following ablation.

10.
J Cardiovasc Electrophysiol ; 25(12): 1275-83, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25132292

RESUMO

BACKGROUND: Visual confirmation of radiofrequency ablation (RFA) lesions during clinical cardiac ablation procedures could improve procedure efficacy, safety, and efficiency. It was previously shown that acoustic radiation force impulse (ARFI) imaging can identify RFA lesions in vitro and in vivo in an animal model. This is the "first-in-human" feasibility demonstration of intracardiac ARFI imaging of RFA lesions in patients undergoing catheter ablation for atrial flutter (AFL) or atrial fibrillation (AF). METHODS AND RESULTS: Patients scheduled for right atrial (RA) ablation for AFL or left atrial (LA) ablation for drug refractory AF were eligible for imaging. Diastole-gated intracardiac ARFI images were acquired using one of two equipment configurations: (1) a Siemens ACUSON S2000™ ultrasound scanner and 8/10Fr AcuNav™ ultrasound catheter, or (2) a CARTO 3™ integrated Siemens SC2000™ and 10Fr SoundStar™ ultrasound catheter. A total of 11 patients (AFL = 3; AF = 8) were imaged. ARFI images were acquired of ablation target regions, including the RA cavotricuspid isthmus (CTI), and the LA roof, pulmonary vein ostia, posterior wall, posterior mitral valve annulus, and the ridge between the pulmonary vein and LA appendage. ARFI images revealed increased relative myocardial stiffness at ablation catheter contact sites after RFA and at anatomical mapping-tagged RFA treatment sites. CONCLUSIONS: ARFI images from a pilot group of patients undergoing catheter ablation for AFL and AF demonstrate the ability of this technique to identify intra-procedure RFA lesion formation. The results encourage further refinement of ARFI imaging clinical tools and continued investigation in larger clinical trials.


Assuntos
Fibrilação Atrial/diagnóstico por imagem , Fibrilação Atrial/cirurgia , Procedimentos Cirúrgicos Cardiovasculares/métodos , Ablação por Cateter/métodos , Técnicas de Imagem por Elasticidade/métodos , Cirurgia Assistida por Computador/métodos , Sistemas Computacionais , Ecocardiografia/métodos , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Resultado do Tratamento
11.
Ultrason Imaging ; 36(3): 167-176, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24626564

RESUMO

We developed new forward-viewing matrix transducers consisting of double ring arrays of 118 total PZT elements integrated into catheters used to deploy medical interventional devices. Our goal is 3D ultrasound guidance of medical device implantation to reduce x-ray fluoroscopy exposure. The double ring arrays were fabricated on inner and outer custom polyimide flexible circuits with inter-element spacing of 0.20 mm and then wrapped around an 11 French (Fr) catheter to produce a 15 Fr catheter (outer diameter [O.D.]). We used a braided cabling technology to connect the elements to the Volumetrics Medical Imaging (VMI) real-time 3D ultrasound scanner. Transducer performance yielded an average -6 dB fractional bandwidth of 49% ± 11% centered at 4.4 MHz for 118 elements. Real-time 3D cardiac scans of the in vivo pig model yielded good image quality including en face views of the tricuspid valve and real-time 3D guidance of an endo-myocardial biopsy catheter introduced into the left ventricle.

12.
Ultrason Imaging ; 36(2): 133-48, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24554293

RESUMO

We have previously shown that intracardiac acoustic radiation force impulse (ARFI) imaging visualizes tissue stiffness changes caused by radiofrequency ablation (RFA). The objectives of this in vivo study were to (1) quantify measured ARFI-induced displacements in RFA lesion and unablated myocardium and (2) calculate the lesion contrast (C) and contrast-to-noise ratio (CNR) in two-dimensional ARFI and conventional intracardiac echo images. In eight canine subjects, an ARFI imaging-electroanatomical mapping system was used to map right atrial ablation lesion sites and guide the acquisition of ARFI images at these sites before and after ablation. Readers of the ARFI images identified lesion sites with high sensitivity (90.2%) and specificity (94.3%) and the average measured ARFI-induced displacements were higher at unablated sites (11.23 ± 1.71 µm) than at ablated sites (6.06 ± 0.94 µm). The average lesion C (0.29 ± 0.33) and CNR (1.83 ± 1.75) were significantly higher for ARFI images than for spatially registered conventional B-mode images (C = -0.03 ± 0.28, CNR = 0.74 ± 0.68).


Assuntos
Ablação por Cateter/métodos , Técnicas de Imagem por Elasticidade/métodos , Aumento da Imagem/métodos , Processamento de Imagem Assistida por Computador/métodos , Animais , Procedimentos Cirúrgicos Cardíacos/métodos , Cães , Átrios do Coração/diagnóstico por imagem , Masculino , Sensibilidade e Especificidade
13.
Angew Chem Int Ed Engl ; 53(38): 10179-83, 2014 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-25079352

RESUMO

Dynamic nuclear polarization surface enhanced NMR (DNP-SENS), Mössbauer spectroscopy, and computational chemistry were combined to obtain structural information on the active-site speciation in Sn-ß zeolite. This approach unambiguously shows the presence of framework Sn(IV)-active sites in an octahedral environment, which probably correspond to so-called open and closed sites, respectively (namely, tin bound to three or four siloxy groups of the zeolite framework).

14.
Front Res Metr Anal ; 8: 1157218, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37492234

RESUMO

Efforts to reduce global greenhouse gas emissions have had limited success. For many, the hopes rest on new energy innovations to advance the energy transition process. In this paper, we develop a Responsible Research and Innovation (RRI) base indicator system to steer the design of innovations in the field of energy transition innovations and, thus, improve social acceptance of these innovations. We propose a guideline for its application to assist R&D performing organizations and funding organizations in the design, selection, and communication of research proposals. The indicator system is intended to promote early integration of environmental and social aspects, support the formation of teams aware of the different responsibility aspects of innovation, and monitor progress in regard to relevant RRI dimensions.

15.
ACS Catal ; 12(9): 5661-5672, 2022 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-35572184

RESUMO

The water gas shift reaction (WGSR) is catalyzed by supported ionic liquid phase (SILP) systems containing homogeneous Ru complexes dissolved in ionic liquids (ILs). These systems work at very low temperatures, that is, between 120 and 160 °C, as compared to >200 °C in the conventional process. To improve the performance of this ultra-low-temperature catalysis, we investigated the influence of various additives on the catalytic activity of these SILP systems. In particular, the application of methylene blue (MB) as an additive doubled the activity. Infrared spectroscopy measurements combined with density functional theory (DFT) calculations excluded a coordinative interaction of MB with the Ru complex. In contrast, state-of-the-art theoretical calculations elucidated the catalytic effect of the additives by non-covalent interactions. In particular, the additives can significantly lower the barrier of the rate-determining step of the reaction mechanism via formation of hydrogen bonds. The theoretical predictions, thereby, showed excellent agreement with the increase of experimental activity upon variation of the hydrogen bonding moieties in the additives investigated.

16.
Artigo em Inglês | MEDLINE | ID: mdl-32894714

RESUMO

Real-time 3-D intracardiac echocardiography (ICE) can enable faster imaging of surfaces orthogonal to the transducer, such as the pulmonary vein (PV) antra and cardiac valve annuli. However, the requirement for a 2-D grid of individually wired elements makes a traditional matrix array challenging to implement within an intravenous catheter. Helicoid array transducers are linear array transducers twisted about their long axis, allowing imaging of different elevation slices using sub-apertures. In this work, we examined the 3-D imaging characteristics of helicoid array transducers through simulations using Field II software and experimental measurements. We report results for varying transducer parameters, such as twist rate and sub-aperture size. We also discuss design considerations for these imaging parameters as they pertain to volumetric imaging of the heart.


Assuntos
Imageamento Tridimensional , Transdutores , Desenho de Equipamento , Imagens de Fantasmas , Ultrassonografia
17.
ACS Omega ; 6(32): 20956-20965, 2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34423203

RESUMO

Defined surface functionalities can control the properties of a material. The layer-by-layer method is an experimentally simple yet very versatile method to coat a surface with nanoscale precision. The method is widely used to either control the chemical properties of the surface via the introduction of functional moieties bound to the polymer or create nanoscale surface topographies if one polymeric species is replaced by a colloidal dispersion. Such roughness can enhance the stability of a liquid film on top of the surface by capillary adhesion. Here, we investigate whether a similar effect allows an increased retention of liquid films within a porous surface and thus potentially increases the stability of ionic liquid films infused within a porous matrix in the supported ionic liquid-phase catalysis. The complex geometry of the porous material, long diffusion pathways, and small sizes of necks connecting individual pores all contribute to difficulties to reliably coat the required porous materials. We optimize the coating process to ensure uniform surface functionalization via two steps. Diffusion limitations are overcome by force-wetting the pores, which transports the functional species convectively into the materials. Electrostatic repulsion, which can limit pore accessibility, is mitigated by the addition of electrolytes to screen charges. We introduce nanoscale topography in microscale porous SiC monoliths to enhance the retention of an ionic liquid film. We use γ-Al2O3 to coat monoliths and test the retention of 1-butyl-2,3-dimethylimidazolium chloride under exposure to a continuous gas stream, a setup commonly used in the water-gas shift reaction. Our study showcases that a hierarchical topography can improve the stability of impregnated ionic liquid films, with a potential advantage of improved supported ionic liquid-phase catalysis.

18.
J Cardiovasc Electrophysiol ; 21(5): 557-63, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20021518

RESUMO

INTRODUCTION: Lesion placement and transmurality are critical factors in the success of cardiac transcatheter radiofrequency ablation (RFA) treatments for supraventricular arrhythmias. This study investigated the capabilities of catheter transducer based acoustic radiation force impulse (ARFI) ultrasound imaging for quantifying ablation lesion dimensions. METHODS AND RESULTS: RFA lesions were created in vitro in porcine ventricular myocardium and imaged with an intracardiac ultrasound catheter transducer capable of acquiring spatially registered B-mode and ARFI images. The myocardium was sliced along the imaging plane and photographed. The maximum ARFI-induced displacement images of the lesion were normalized and spatially registered with the photograph by matching the surfaces of the tissue in the B-mode and photographic images. The lesion dimensions determined by a manual segmentation of the photographed lesion based on the visible discoloration of the tissue were compared to automatic segmentations of the ARFI image using 2 different calculated thresholds. ARFI imaging accurately localized and sized the lesions within the myocardium. Differences in the maximum lateral and axial dimensions were statistically below 2 mm and 1 mm, respectively, for the 2 thresholding methods, with mean percent overlap of 68.7 +/- 5.21% and 66.3 +/- 8.4% for the 2 thresholds used. CONCLUSION: ARFI imaging is capable of visualizing myocardial RFA lesion dimensions to within 2 mm in vitro. Visualizing lesions during transcatheter cardiac ablation procedures could improve the success of the treatment by imaging lesion line discontinuity and potentially reducing the required number of ablation lesions and procedure time.


Assuntos
Ablação por Cateter/efeitos adversos , Diagnóstico por Imagem/métodos , Miocárdio/patologia , Animais , Elasticidade , Processamento de Imagem Assistida por Computador , Suínos
19.
Ann Vasc Surg ; 24(3): 416.e9-416.e12, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20036509

RESUMO

Atheroembolic disease typically presents with isolated lower extremity digital ischemia. Treatment traditionally includes optimization of medical management, with open surgery reserved for complicated or recurrent embolic events. We present a novel endovascular approach for treatment of complicated thoracic aortic atherosclerotic disease incidentally discovered in a 63-year-old female. The patient demonstrated visceral artery embolization from a mobile 2.6 cm atherosclerotic plaque despite maximal medical therapy. Thoracic aortic stent graft placement successfully excluded the atheroma and prevented further embolization. This case demonstrates a unique treatment option for complicated thoracic aortic atheroembolic disease utilizing a minimally invasive endovascular approach.


Assuntos
Aorta Torácica/cirurgia , Doenças da Aorta/cirurgia , Ruptura Aórtica/cirurgia , Aterosclerose/cirurgia , Implante de Prótese Vascular , Embolia de Colesterol/cirurgia , Trombose/cirurgia , Aorta Torácica/diagnóstico por imagem , Doenças da Aorta/complicações , Doenças da Aorta/diagnóstico , Ruptura Aórtica/diagnóstico , Ruptura Aórtica/etiologia , Aortografia/métodos , Aterosclerose/complicações , Aterosclerose/diagnóstico , Prótese Vascular , Implante de Prótese Vascular/instrumentação , Ecocardiografia Transesofagiana , Embolia de Colesterol/diagnóstico , Embolia de Colesterol/etiologia , Feminino , Humanos , Achados Incidentais , Pessoa de Meia-Idade , Índice de Gravidade de Doença , Stents , Trombose/complicações , Trombose/diagnóstico , Tomografia Computadorizada por Raios X , Resultado do Tratamento
20.
Chem Sci ; 11(29): 7593-7598, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-34094136

RESUMO

Small and narrowly distributed nanoparticles of copper alloyed with gallium supported on silica containing residual GaIII sites can be obtained via surface organometallic chemistry in a two-step process: (i) formation of isolated GaIII surface sites on SiO2 and (ii) subsequent grafting of a CuI precursor, [Cu(O t Bu)]4, followed by a treatment under H2 to generate CuGa x alloys. This material is highly active and selective for CO2 hydrogenation to CH3OH. In situ X-ray absorption spectroscopy shows that gallium is oxidized under reaction conditions while copper remains as Cu0. This CuGa material only stabilizes methoxy surface species while no formate is detected according to ex situ infrared and solid-state nuclear magnetic resonance spectroscopy.

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