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1.
Angew Chem Int Ed Engl ; 63(14): e202319192, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38271543

RESUMO

Improving the selectivity in the oxidative coupling of methane to ethane/ethylene poses a significant challenge for commercialization. The required improvements are hampered by the uncertainties associated with the reaction mechanism due to its complexity. Herein, we report about 90 % selectivity to the target products at 11 % methane conversion over Gd2O3-based catalysts at 700 °C using N2O as the oxidant. Sophisticated kinetic studies have suggested the nature of adsorbed oxygen species and their binding strength as key parameters for undesired methane oxidation to carbon oxides. These descriptors can be controlled by a metal oxide promoter for Gd2O3.

2.
ACS Catal ; 13(24): 15977-15990, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-38125976

RESUMO

The development of selective catalysts for direct conversion of ammonia into nitrous oxide, N2O, will circumvent the conventional five-step manufacturing process and enable its wider utilization in oxidation catalysis. Deviating from commonly accepted catalyst design principles for this reaction, reliant on manganese oxide, we herein report an efficient system comprised of isolated chromium atoms (1 wt %) stabilized in the ceria lattice by coprecipitation. The latter, in contrast to a simple impregnation approach, ensures firm metal anchoring and results in stable and selective N2O production over 100 h on stream up to 79% N2O selectivity at full NH3 conversion. Raman, electron paramagnetic resonance, and in situ UV-vis spectroscopies reveal that chromium incorporation enhances the density of oxygen vacancies and the rate of their generation and healing. Accordingly, temporal analysis of products, kinetic studies, and atomistic simulations show lattice oxygen of ceria to directly participate in the reaction, establishing the cocatalytic role of the carrier. Coupled with the dynamic restructuring of chromium sites to stabilize intermediates of N2O formation, these factors enable catalytic performance on par with or exceeding benchmark systems. These findings demonstrate how nanoscale engineering can elevate a previously overlooked metal into a highly competitive catalyst for selective ammonia oxidation to N2O, paving the way toward industrial implementation.

3.
Angew Chem Int Ed Engl ; 62(49): e202310062, 2023 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-37702304

RESUMO

Knowing the structure of catalytically active species/phases and providing methods for their purposeful generation are two prerequisites for the design of catalysts with desired performance. Herein, we introduce a simple method for precise preparation of supported/bulk catalysts. It utilizes the ability of metal oxides to dissolve and to simultaneously precipitate during their treatment in an aqueous ammonia solution. Applying this method for a conventional VOx -Al2 O3 catalyst, the concentration of coordinatively unsaturated Al sites was tuned simply by changing the pH value of the solution. These sites affect the strength of V-O-Al bonds of isolated VOx species and thus the reducibility of the latter. This method is also applicable for controlling the reducibility of bulk catalysts as demonstrated for a CeO2 -ZrO2 -Al2 O3 system. The application potential of the developed catalysts was confirmed in the oxidative dehydrogenation of ethylbenzene to styrene with CO2 and in the non-oxidative propane dehydrogenation to propene. Our approach is extendable to the preparation of any metal oxide catalysts dissolvable in an ammonia solution.

4.
J Phys Condens Matter ; 35(40)2023 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-37364587

RESUMO

Polarization dependent x-ray absorption spectroscopy was used to study the magnetic ground state and the orbital occupation in bulk-phase VI3van der Waals crystals below and above the ferromagnetic and structural transitions. X-ray natural linear dichroism and x-ray magnetic circular dichroism spectra acquired at the VL2,3edges are compared against multiplet cluster calculations within the frame of the ligand field theory to quantify the intra-atomic electronic interactions at play and evaluate the effects of symmetry reduction occurring in a trigonally distorted VI6unit. We observed a non zero linear dichroism proving the presence of an anisotropic charge density distribution around the V3+ion due to the unbalanced hybridization between the vanadium and the ligand states. Such hybridization acts as an effective trigonal crystal field, slightly lifting the degeneracy of thet2g2ground state. However, the energy splitting associated to the distortion underestimates the experimental band gap, suggesting that the insulating ground state is stabilized by Mott correlation effects rather than via a Jahn-Teller mechanism. Our results clarify the role of the distortion in VI3and establish a benchmark for the study of the spectroscopic properties of other van der Waals halides, including emerging 2D materials with mono and few-layers thickness, whose fundamental properties might be altered by reduced dimensions and interface proximity.

5.
Adv Mater ; 35(24): e2211260, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36863934

RESUMO

Nitrous oxide, N2 O, exhibits unique reactivity in oxidation catalysis, but the high manufacturing costs limit its prospective uses. Direct oxidation of ammonia, NH3 , to N2 O can ameliorate this issue but its implementation is thwarted by suboptimal catalyst selectivity and stability, and the lack of established structure-performance relationships. Systematic and controlled material nanostructuring offers an innovative approach for advancement in catalyst design. Herein low-valent manganese atoms stabilized on ceria, CeO2 , are discovered as the first stable catalyst for NH3 oxidation to N2 O, exhibiting two-fold higher productivity than the state-of-the-art. Detailed mechanistic, computational and kinetic studies reveal CeO2 as the mediator of oxygen supply, while undercoordinated manganese species activate O2 and facilitate N2 O evolution via NN bond formation between nitroxyl, HNO, intermediates. Synthesis via simple impregnation of a small metal quantity (1 wt%) predominantly generates isolated manganese sites, while full atomic dispersion is achieved upon redispersion of sporadic oxide nanoparticles during reaction, as confirmed by advanced microscopic analysis and electron paramagnetic resonance spectroscopy. Subsequently, manganese speciation is maintained, and no deactivation is observed over 70 h on stream. CeO2 -supported isolated transition metals emerge as a novel class of materials for N2 O production, encouraging future studies to evaluate their potential in selective catalytic oxidations at large.

7.
Eur Psychiatry ; 65(1): e81, 2022 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-36328964

RESUMO

BACKGROUND: In recent years, numerous studies have highlighted the overlap between autism spectrum disorder (ASD) and catatonia, both from a clinical and pathophysiological perspective. This study aimed to investigate the relationship between the autism spectrum (autistic traits and ASD signs, symptoms, and behavioral manifestation) and Catatonia Spectrum (CS). METHODS: A total sample of 376 subjects was distributed in four diagnostic groups. Subjects were assessed with the Structured Clinical Interview for DSM-5, Research Version, the Adult Autism Subthreshold Spectrum (AdAS Spectrum), and CS. In the statistical analyses, the total sample was also divided into three groups according to the degree of autism severity, based on the AdAS Spectrum total score. RESULTS: A statistically significant positive correlation was found between AdAS Spectrum and CS total score within the total sample, the gender subgroups, and the diagnostic categories. The AdAS Spectrum domains found to be significantly and strongly correlated with the total CS score were hyper-hypo reactivity to sensory input, verbal communication, nonverbal communication, restricted interests and rumination, and inflexibility and adherence to routine. The three groups of different autistic severity were found to be distributed across all diagnostic groups and the CS score increased significantly from the group without autistic traits to the group with ASD. CONCLUSIONS: Our study reports a strong correlation between autism spectrum and CS.


Assuntos
Transtorno do Espectro Autista , Transtorno Autístico , Catatonia , Adulto , Humanos , Catatonia/diagnóstico , Transtorno Autístico/diagnóstico , Transtorno do Espectro Autista/diagnóstico
8.
Nat Nanotechnol ; 17(6): 606-612, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35484211

RESUMO

Controlling the precise atomic architecture of supported metals is central to optimizing their catalytic performance, as recently exemplified for nanostructured platinum and ruthenium systems in acetylene hydrochlorination, a key process for vinyl chloride production. This opens the possibility of building on historically established activity correlations. In this study, we derived quantitative activity, selectivity and stability descriptors that account for the metal-dependent speciation and host effects observed in acetylene hydrochlorination. To achieve this, we generated a platform of Au, Pt, Ru, Ir, Rh and Pd single atoms and nanoparticles supported on different types of carbon and assessed their evolution during synthesis and under the relevant reaction conditions. Combining kinetic, transient and chemisorption analyses with modelling, we identified the acetylene adsorption energy as a speciation-sensitive activity descriptor, further determining catalyst selectivity with respect to coke formation. The stability of the different nanostructures is governed by the interplay between single atom-support interactions and chlorine affinity, promoting metal redispersion or agglomeration, respectively.

9.
Angew Chem Int Ed Engl ; 61(22): e202116517, 2022 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-35244964

RESUMO

Alkali metal promoters have been widely employed for preparation of heterogeneous catalysts used in many industrially important reactions. However, the fundamentals of their effects are usually difficult to access. Herein, we unravel mechanistic and kinetic aspects of the role of alkali metals in CO2 hydrogenation over Fe-based catalysts through state-of-the-art characterization techniques, spatially resolved steady-state and transient kinetic analyses. The promoters affect electronic properties of iron in iron carbides. These carbide characteristics determine catalyst ability to activate H2 , CO and CO2 . The Allen scale electronegativity of alkali metal promoter was successfully correlated with the rates of CO2 hydrogenation to higher hydrocarbons and CH4 as well as with the rate constants of individual steps of CO or CO2 activation. The derived knowledge can be valuable for designing and preparing catalysts applied in other reactions where such promoters are also used.

11.
Angew Chem Int Ed Engl ; 61(19): e202200772, 2022 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-35148454

RESUMO

The production of nitrous oxide, N2 O, via NH3 oxidation is not on a practical scale due to the lack of a suitable catalyst. Instead, it is produced via thermal decomposition of NH4 NO3 , rendering N2 O too costly and limiting its prospective uses. Herein, we report CeO2 -supported Au nanoparticles (2-3 nm) as a highly selective catalyst for low-temperature NH3 oxidation to N2 O, exhibiting two orders of magnitude higher space-time yield than the state-of-the-art Mn-Bi/α-Al2 O3 and remarkable stability over 70 h on stream. The reaction proceeds via a Mars-van Krevelen mechanism, with the density of interfacial Auδ+ species and the oxygen storage capacity of CeO2 identified as the key performance descriptors. The latter could be enhanced by cobalt doping, improving the catalytic activity and setting a new benchmark for N2 O productivity. These findings establish NH3 oxidation as an efficient process for N2 O manufacture and facilitate its broader utilization in selective oxidations.

13.
J Affect Disord ; 298(Pt A): 442-450, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-34742998

RESUMO

BACKGROUND: Treatment resistant depression (TRD) is diagnosed when patients experiencing a major depressive episode fail to respond to ≥2 treatments. Along with substantial indirect costs, patients with TRD have higher healthcare resource utilization (HCRU) than other patients with depression. However, research on the economic impact of this HCRU, and differences according to response to treatment, is lacking. METHODS: This multicenter, observational study documented HCRU among patients with TRD in European clinical practice initiating new antidepressant treatments. Data regarding access to outpatient consultations and other healthcare resources for the first 6 months, collected using a questionnaire, were analyzed qualitatively according to response and remission status. The economic impact of HCRU, estimated using European costing data, was analyzed quantitatively. RESULTS: Among 411 patients, average HCRU was higher in non-responders, attending five times more general practitioner (GP) consultations and spending longer in hospital (1.7 versus 1.1 days) than responders. Greater differences were observed according to remission status, with non-remitters attending seven times more GP consultations and spending approximately three times longer in hospital (1.7 versus 0.6 days) than remitters. Consequently, the estimated economic impacts of non-responders and non-remitters were significantly greater than those of responders and remitters, respectively. LIMITATIONS: Key limitations are small cohort size, absence of control groups and generalizability to different healthcare systems. CONCLUSION: Patients with TRD, particularly those not achieving remission, have considerable HCRU, with associated economic impact. The costs of unmet TRD treatment needs are thus substantial, and treatment success is fundamental to reduce individual needs and societal costs.


Assuntos
Transtorno Depressivo Maior , Transtorno Depressivo Resistente a Tratamento , Estudos de Coortes , Atenção à Saúde , Transtorno Depressivo Maior/tratamento farmacológico , Transtorno Depressivo Resistente a Tratamento/tratamento farmacológico , Custos de Cuidados de Saúde , Humanos , Estudos Retrospectivos
14.
Nature ; 599(7884): 234-238, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34759363

RESUMO

Propane dehydrogenation (PDH) to propene is an important alternative to oil-based cracking processes, to produce this industrially important platform chemical1,2. The commercial PDH technologies utilizing Cr-containing (refs. 3,4) or Pt-containing (refs. 5-8) catalysts suffer from the toxicity of Cr(VI) compounds or the need to use ecologically harmful chlorine for catalyst regeneration9. Here, we introduce a method for preparation of environmentally compatible supported catalysts based on commercial ZnO. This metal oxide and a support (zeolite or common metal oxide) are used as a physical mixture or in the form of two layers with ZnO as the upstream layer. Supported ZnOx species are in situ formed through a reaction of support OH groups with Zn atoms generated from ZnO upon reductive treatment above 550 °C. Using different complementary characterization methods, we identify the decisive role of defective OH groups for the formation of active ZnOx species. For benchmarking purposes, the developed ZnO-silicalite-1 and an analogue of commercial K-CrOx/Al2O3 were tested in the same setup under industrially relevant conditions at close propane conversion over about 400 h on propane stream. The developed catalyst reveals about three times higher propene productivity at similar propene selectivity.

15.
Psychiatry Res ; 295: 113556, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33189367

RESUMO

Psychotherapy is the cornerstone of treatment for borderline personality disorder (BPD) while pharmacotherapy should be considered only as an adjunctive intervention. In clinical practice, however, most of BPD patients only receive medication. The aim of the study is to first describe pharmacological treatment in BPD patients in Italy and secondly to evaluate if comorbidity or illness severity are associated with the prescription of different class compounds. Data on pharmacological treatment and clinical evaluation of 75 BPD patients were collected in 5 clinical settings. The association between comorbidity and medication was assessed. Moreover, we evaluated the association between pharmacotherapy and severity, defined by a cluster analysis aimed at detecting different groups of patients. Most of the participants (82.7%) were characterized by polypharmacy, with a mean of 2.4 medications per person. Interestingly, the prescription didn't seem to depend on/be based on the severity of the disorder and was only partially determined by the presence of comorbidity. In conclusion, our findings are similar to what described in other clinical studies, supporting the idea that medication management for BPD is only partially coherent with international guidelines. This pilot study confirms the need for more rigorous studies to gain greater understanding of this topic and diminish the gap between guidelines and the real clinical world.


Assuntos
Transtorno da Personalidade Borderline/terapia , Prescrições de Medicamentos/estatística & dados numéricos , Guias de Prática Clínica como Assunto , Padrões de Prática Médica/estatística & dados numéricos , Psicoterapia/métodos , Psicotrópicos/uso terapêutico , Adulto , Idoso , Transtorno da Personalidade Borderline/epidemiologia , Transtorno da Personalidade Borderline/psicologia , Comorbidade , Feminino , Humanos , Itália/epidemiologia , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Polimedicação , Índice de Gravidade de Doença
16.
Chem Soc Rev ; 50(1): 473-527, 2021 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-33205797

RESUMO

Conversion of propane or butanes from natural/shale gas into propene or butenes, which are indispensable for the synthesis of commodity chemicals, is an important environmentally friendly alternative to oil-based cracking processes. Herein, we critically analyse recent developments in the non-oxidative, oxidative, and CO2-mediated dehydrogenation of propane and isobutane to the corresponding olefins over metal oxide catalysts. Particular attention is paid to (i) comparing the developed catalysts in terms of their application potential, (ii) structure-activity-selectivity relationships for tailored catalyst design, and (iii) reaction-engineering aspects for improving product selectivity and overall process efficiency. On this basis, possible directions for further research aimed at the development of inexpensive and environmentally friendly catalysts with industrially relevant performance were identified. In addition, we provide general information regarding catalyst preparation and characterization as well as some recommendations for carrying out non-oxidative and CO2-mediated dehydrogenation reactions to ensure unambiguous comparison of catalysts developed in different studies.

17.
Chem Commun (Camb) ; 56(85): 13021-13024, 2020 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-33000811

RESUMO

This paper demonstrates the potential of Eu2O3 and Gd2O3 as catalysts for non-oxidative propane dehydrogenation to propene. They reveal a higher activity than the state-of-the-art bare ZrO2-based catalysts due to the higher intrinsic activity of Gdcus or Eucus in comparison with that of Zrcus (cus = coordinatively unsaturated).

18.
Environ Sci Technol ; 54(19): 11753-11761, 2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-32790302

RESUMO

The impact of formaldehyde (HCHO, formed in vehicle exhaust gases by incomplete combustion of fuel) on the performance of a commercial V2O5-WO3/TiO2 catalyst in NH3-SCR of NOx under dry conditions has been analyzed in detail by catalytic tests, in situ FTIR and transient studies using temporal analysis of products (TAP). HCHO reacts preferentially with NH3 to a formamide (HCONH2) surface intermediate. This deprives NH3 partly from its desired role as a reducing agent in the SCR and diminishes NO conversion and N2 selectivity. Between 250 and 400 °C, HCONH2 decomposes by dehydration (major pathway) and decarbonylation (minor pathway) to liberate toxic HCN and CO, respectively. HCN was proven to be oxidized by lattice oxygen of the catalyst to CO2 and NO, which enters the NH3-SCR reaction.


Assuntos
Amônia , Titânio , Catálise , Formaldeído
19.
Ir J Psychol Med ; 37(4): 283-290, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32368994

RESUMO

OBJECTIVES.: To assess admission rates to seven General Hospital Psychiatric Wards (GHPWs) located in the Lombardy Region in the 40 days after the start of Coronavirus disease 2019 (COVID-19) epidemic, compared to similar periods of 2020 and 2019. METHODS.: Anonymized data from the regional psychiatric care register have been obtained and analyzed. The seven GHPWs care for approximately 1.4 million inhabitants and have a total of 119 beds. RESULTS.: In the 40-day period (February 21-March 31, 2020) after the start of the COVID-19 epidemic in Italy, compared to a similar 40-day period prior to February 21, and compared to two 40-day periods of 2019, there has been a marked reduction in psychiatric admission rates. The reduction was explained by voluntary admissions, while there was not a noticeable reduction for involuntary admissions. The reduction was visible for all diagnostic groups, except for a group of 'Other' diagnoses, which includes anxiety disorders, neurocognitive disorders, etc. CONCLUSIONS.: Large-scale pandemics can modify voluntary admission rates to psychiatric facilities in the early phases following pandemic onset. We suggest that the reduction in admission rates may be due to fear of hospitals, seen as possible sites of contagion, as well as to a change in thresholds of behavioral problems acting as a trigger for admission requests from family relatives or referrals from treating clinicians. It is unclear from the study whether the reduction in admissions was contributed to most by the current pandemic or the lockdown imposed due to the pandemic.


Assuntos
COVID-19/epidemiologia , Hospitalização/estatística & dados numéricos , Transtornos Mentais/epidemiologia , Humanos , Itália , Transtornos Mentais/terapia , Serviços de Saúde Mental/estatística & dados numéricos , Admissão do Paciente/estatística & dados numéricos , Sistema de Registros
20.
Schizophr Res ; 216: 243-248, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31818634

RESUMO

Negative symptoms of schizophrenia have a great impact on patients' functioning and are among the most important contributors to subject's disability. However, few studies have assessed the role of type and severity of symptomatology of schizophrenia on the psychiatric care resource utilization. We investigated if the clinical profile of patients at discharge from an index hospitalization might be associated with a different use of psychiatric care resources in the subsequent 1-year period in a large population of patients with schizophrenia spectrum disorders. Clinical records of 450 patients with schizophrenia spectrum disorders admitted in an acute psychiatric inpatient service and subsequently followed in the outpatient services of the same Department were reviewed. Patients with more severe negative symptoms at discharge from hospital showed a higher number and duration of hospitalizations in the 1-year follow-up, as well as a higher number of rehabilitative residential admissions than patients with milder severity of negative symptoms. The same was true for patients with predominant negative symptoms. A global resource utilization index indicated a higher use of psychiatric resources in patients with higher severity of negative symptoms. In conclusion, showing moderate to severe negative symptoms versus positive symptoms at discharge from a hospitalization for an acute exacerbation of schizophrenia spectrum disorder does predict a higher use of psychiatric care resources. This underlines the importance of relieving negative symptoms even in the acute phase of treatment and the need to develop more effective treatments for this symptom dimension.


Assuntos
Esquizofrenia , Seguimentos , Hospitalização , Humanos , Alta do Paciente , Estudos Retrospectivos , Esquizofrenia/epidemiologia , Esquizofrenia/terapia
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