Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 101
Filtrar
1.
J Phys Chem Lett ; : 7411-7418, 2024 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-38995886

RESUMO

The interplay between laboratory rotational spectroscopy and radio astronomical observations provides the most effective procedure for identifying molecules in the interstellar medium (ISM). Following the recent interstellar detections of several Polycyclic Aromatic Hydrocarbons (PAHs) and cyano derivatives in the dense molecular cloud TMC-1, it is reasonable to consider searching for other cyano-PAHs in this astronomical source. We present a rotational spectroscopy investigation of the two cyano derivatives of the PAH biphenylene, a plausible reaction product of interstellar benzyne. The rotational spectrum provided molecular parameters for the parent species and 14 monosubstituted isotopologues for each isomer. An accurate equilibrium structure was determined for both isomers using Watson's mass-dependence method (rm(2)), offering information on its uncommon ring union. Astronomical searches for the cyanobiphenylene isomers have been undertaken in TMC-1, using the QUIJOTE line survey. No lines of any isomer were found in this astronomical source, but the experimental data will serve to enable future searches for these species in the ISM.

2.
Chemistry ; : e202402297, 2024 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-39032069

RESUMO

The on-surface synthesis of an isomer of undecacene, bearing two four-membered rings and two para-quinodimethane moieties, starting from a tetramethyl-substituted diepoxy precursor, is presented. The transformation implies a thermal double deoxygenation followed by a stepwise double dehydrogenation reaction on the Au(111) surface, locally induced by inelastic tunneling electrons. This results in the transformation of para-dimethylbenzene moieties into non-aromatic para-quinodimethanes. The structures and electronic properties of the intermediate and final products are investigated at the single molecule level with high spatial resolution, using both scanning tunneling microscopy/spectroscopy and non-contact atomic force microscopy. The experimental results are supported by density functional theory calculations.

3.
Eur Child Adolesc Psychiatry ; 33(1): 203-228, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36757483

RESUMO

The main objective of the review is to analyze the impact of the pandemic in children/teenagers with Autism spectrum disorder (ASD) and in their family environment. An electronic search was carried out in different databases (PsycInfo, Web of Science and Scopus) in order to find publications associated with the aim of this project. The search terms used were derived from the combination of the following search string: "((Pandemic OR Epidemic OR Outbreak OR COVID-19 OR Coronavirus) AND (Children OR Adolescents OR Youth OR Child OR Teenager) AND (Autism OR ASD OR Autism Spectrum Disorder))''. In total, 21 articles were included in this review. The findings of the different investigations included in this review show that the pandemic has produced a negative psychological impact in children/teenagers with ASD. Therefore, long-term follow-up studies should be carried out with the objective of creating effective interventions to treat this problematical.


Assuntos
Transtorno do Espectro Autista , COVID-19 , Criança , Adolescente , Humanos , COVID-19/epidemiologia , Transtorno do Espectro Autista/epidemiologia , Transtorno do Espectro Autista/terapia , Pandemias , Surtos de Doenças
4.
J Phys Chem Lett ; 14(46): 10442-10449, 2023 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-37962022

RESUMO

On-surface synthesis has emerged as an attractive method for the atomically precise synthesis of new molecular nanostructures, being complementary to the widespread approach based on solution chemistry. It has been particularly successful in the synthesis of graphene nanoribbons and nanographenes. In both cases, the target compound is often generated through cyclodehydrogenation reactions, leading to planarization and the formation of hexagonal rings. To improve the flexibility and tunability of molecular units, however, the incorporation of other, nonbenzenoid, subunits is highly desirable. In this letter, we thoroughly analyze sequential cyclodehydrogenation reactions with a custom-designed molecular precursor. We demonstrate the step-by-step formation of hexagonal and pentagonal rings from the nonplanar precursor within fjord and cove regions, respectively. Computer models comprehensively support the experimental observations, revealing that both reactions imply an initial hydrogen abstraction and a final [1,2] hydrogen shift, but the formation of a pentagonal ring proceeds through a radical mechanism.

5.
Int J Food Microbiol ; 399: 110254, 2023 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-37244227

RESUMO

The increasing demand for more flavored and complex beers encourages the investigation of novel and non-conventional yeasts with the ability to provide a combination of bioflavoring and low ethanol yields. The present study identified 22 yeasts isolated from different brewing sources, including the fermentation by-products known as yeast sludges, and characterized a selection of strains to find the more suitable for the aforementioned aims. HPLC and GC-FID analysis of its brewing products were performed. The most promising results were obtained with the non-conventional yeasts Pichia kudriavzevii MBELGA61 and Meyerozyma guilliermondii MUS122. The former, isolated from a Belgian wheat beer sludge, was capable of growing in wort (17.0°Bx., 20 °C) with very low ethanol yields (1.19 % v/v). Besides, upon mixed fermentations with Saccharomyces cerevisiae, was suitable to produce volatile compounds such as ethyl acetate, 2-phenyl ethanol and isoamyl alcohol, with characteristic fruity notes. M. guilliermondii MUS122, isolated from a golden ale beer sludge, partially attenuated the wort with low production of ethanol and biomass. In addition, provided some fruity and floral nuances to the aroma profile of mixed fermentations with brewer's yeast. The results suggest that these strains favor the development of more fruity-flowery aroma profiles in beers. Furthermore, they are suitable for use in mixed fermentations with Saccharomyces brewer's strains, although the ethanol level did not decrease significantly.


Assuntos
Cerveja , Esgotos , Fermentação , Cerveja/análise , Leveduras , Saccharomyces cerevisiae , Etanol/análise
6.
Sci Rep ; 13(1): 6722, 2023 04 25.
Artigo em Inglês | MEDLINE | ID: mdl-37185929

RESUMO

Retrospective perceptions of parental bonding may be a protective factor for emotional health. These perceptions are grounded in autobiographical memory, which plays a key role in the onset and maintenance of depressive symptomatology. The aim of the present study was to explore whether the emotional valence of autobiographical memories (positive and negative) and the dimensions of parental bonding (care and protection) have an impact on depressive symptomatology, examining the role of depressive rumination and possible age-related differences. A total of 139 young adults (18-28 years) and 124 older adults (65-88 years) completed the Parental Bonding Instrument, the Beck Depression Inventory (BDI-II), the Autobiographical Memory Test and the Short Depressive Rumination Scale. Our results show that positive autobiographical memories serve as a protective factor for depressive symptoms in both young and older adults. Additionally, in young adults, high paternal care and protection scores are associated with increased negative autobiographical memories, although this association has no effect on depressive symptomatology. In older adults, high maternal protection scores are directly related to greater depressive symptomatology. Depressive rumination significantly increases depressive symptoms in both young and older adults, with an increase in negative autobiographical memories in young adults, and a decrease in such memories in older adults. Our findings progress the understanding of the relationships between parental bonding and autobiographical memory with respect to emotional disorders, which, in turn, will help in the design of effective prevention measures.


Assuntos
Depressão , Memória Episódica , Adulto Jovem , Humanos , Idoso , Depressão/psicologia , Estudos Retrospectivos , Emoções , Pais , Rememoração Mental
7.
ACS Nano ; 17(3): 2580-2587, 2023 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-36692226

RESUMO

The formation of two types of nanographenes from custom designed and synthesized molecular precursors has been achieved through thermally induced intramolecular cyclodehydrogenation reactions on the semiconducting TiO2(110)-(1×1) surface, confirmed by the combination of high-resolution scanning tunneling microscopy (STM) and spectroscopy (STS) measurements, and corroborated by theoretical modeling. The application of this protocol on differently shaped molecular precursors demonstrates the ability to induce a highly efficient planarization reaction both within strained pentahelicenes as well as between vicinal phenyl rings. Additionally, by the combination of successive Ullmann-type polymerization and cyclodehydrogenation reactions, the archetypic 7-armchair graphene nanoribbons (7-AGNRs) have also been fabricated on the titanium dioxide surface from the standard 10,10'-dibromo-9,9'-bianthryl (DBBA) molecular precursors. These examples of the effective cyclodehydrogenative planarization processes provide perspectives for the rational design and synthesis of molecular nanostructures on semiconductors.

8.
J Phys Chem Lett ; 14(4): 947-953, 2023 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-36688740

RESUMO

Activating the strong C-C σ-bond is a central problem in organic synthesis. Directly generating activated C centers by metalation of structures containing strained four-membered rings is one maneuver often employed in multistep syntheses. This usually requires high temperatures and/or precious transition metals. In this paper, we report an unprecedented C-C σ-bond activation at room temperature on Cu(111). By using bond-resolving scanning probe microscopy, we show the breaking of one of the C-C σ-bonds of a biphenylene derivative, followed by insertion of Cu from the substrate. Chemical characterization of the generated species was complemented by X-ray photoemission spectroscopy, and their reactivity was explained by density functional theory calculations. To gain further insight into this unique reactivity on other coinage metals, the reaction pathway on Ag(111) was also investigated and the results were compared with those on Cu(111). This study offers new synthetic routes that may be employed in the in situ generation of activated species for the on-surface synthesis of novel C-based nanostructures.

9.
Psychol Res ; 87(4): 988-1011, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35859072

RESUMO

There is evidence to support the positive contribution of autobiographical recall based techniques on individuals' quality of life, mood and cognitive functioning. In this review, we analyzed the effects of the use of personal photographs in interventions based on autobiographical memory in older people with and without cognitive impairment. The PRISMA guidelines for systematic reviews were followed. The search was carried out in the electronic databases Web of Sciences (WOS), Medline (PubMed), SCIELO and PsycInfo (American Psychological Association). The articles based on clinical trials selected were evaluated using the PEDRo scale, which is specific to this type of article. Of the 1098 articles initially found, 6 met the inclusion criteria. The final articles focused their intervention on the use of autobiographical photographs as a means of stimulation. The results show that the use of photographs in different autobiographical recall stimulation techniques is associated with higher scores on well-being and quality of life, as well as with improvements in personal identity and cognitive functioning. This suggests that using personal photographs shows promise in enhancing the effect of these types of interventions in healthy or cognitively impaired older adults.


Assuntos
Disfunção Cognitiva , Qualidade de Vida , Humanos , Idoso , Emoções , Cognição , Rememoração Mental
10.
PLoS One ; 17(6): e0269381, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35759458

RESUMO

BACKGROUND: In recent years, mood induction procedures have been developed in experimental settings that are designed to facilitate studying the impact of mood states on biological and psychological processes. The aim of the present study was to conduct a systematic mapping review with the intention of describing the state of the art in the use of different types of autobiographical stimuli for mood induction procedures. METHODS: Based on a search for publications from the period 2000-2021, conducted in four recognised databases (Scopus, Medline (PubMed), PsycINFO and Web of Science), we analysed a total of 126 published articles. Text mining techniques were used to extract the main themes related. RESULTS: The induction of emotions through autobiographical memories is an area under construction and of growing interest. The data mining approach yielded information about the main types of stimuli used in these procedures, highlighting those that only employ a single type of cue, as well as the preference for verbal cues over others such as musical, olfactory and visual cues. This type of procedure has been used to induce both positive and negative emotions through tasks that require access to personal memories of specific events from a cue, requiring the person to set in motion different cognitive processes. The use of the latest technologies (fMRI, EEG, etc.) is also shown, demonstrating that this is a cutting-edge field of study. CONCLUSIONS: Despite the study of mood induction procedures still being a growing field, the present review provides a novel overview of the current state of the art in the field, which may serve as a framework for future studies on the topic.


Assuntos
Afeto , Memória Episódica , Sinais (Psicologia) , Emoções , Humanos , MEDLINE , Rememoração Mental
11.
Microb Biotechnol ; 15(8): 2266-2280, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35485391

RESUMO

Non-wine yeasts could enhance the aroma and organoleptic profile of wines. However, compared to wine strains, they have specific intolerances to winemaking conditions. To solve this problem, we generated intra- and interspecific hybrids using a non-GMO technique (rare-mating) in which non-wine strains of S. uvarum, S. kudriavzevii and S. cerevisiae species were crossed with a wine S. cerevisiae yeast. The hybrid that inherited the wine yeast mitochondrial showed better fermentation capacities, whereas hybrids carrying the non-wine strain mitotype reduced ethanol levels and increased glycerol, 2,3-butanediol and organic acid production. Moreover, all the hybrids produced several fruity and floral aromas compared to the wine yeast: ß-phenylethyl acetate, isobutyl acetate, γ-octalactone, ethyl cinnamate in both varietal wines. Sc × Sk crosses produced three- to sixfold higher polyfunctional mercaptans, 4-mercapto-4-methylpentan-2-one (4MMP) and 3-mercaptohexanol (3MH). We proposed that the exceptional 3MH release observed in an S. cerevisiae × S. kudriavzevii hybrid was due to the cleavage of the non-volatile glutathione precursor (Glt-3MH) to detoxify the cell from the presence of methylglyoxal, a compound related to the high glycerol yield reached by this hybrid. In conclusion, hybrid generation allows us to obtain aromatically improved yeasts concerning their wine parent. In addition, they reduced ethanol and increased organic acids yields, which counteracts climate change effect on grapes.


Assuntos
Saccharomyces , Etanol , Fermentação , Glicerol , Saccharomyces/genética , Saccharomyces cerevisiae/genética
12.
Food Microbiol ; 104: 103981, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35287810

RESUMO

Saccharomyces yeasts from different origins and species fermented in a semi-synthetic must containing aroma precursor of cv. Albariño and polyfunctional mercaptans precursors. The resulting wines were subjected to accelerate anoxic aging. Afterward, aroma profiles were analyzed by distinct gas chromatography methodologies. Cryotolerant strains showed better fermentation performances with significant differences in volatile and non-volatile fermentation products than Saccharomyces cerevisiae (S. cerevisiae). We suggested that the highest levels γ-butyrolactone and diethyl succinate in Saccharomyces uvarum (S. uvarum) strains, together with their substantial succinic acid yields, could be related to greater flux through the GABA shunt. These strains also had the highest production of ß-phenylethyl acetate, geraniol, and branched-chain ethyl esters. The latter compounds were highly increased by aging, while acetates and some terpenes decreased. S. kudriavzevii strains showed a remarkable ability to release polyfunctional mercaptans, with SK1 strain yielding up to 47-fold and 8-fold more 4-methyl-4-mercaptopentan-2-one (4MMP) than S. cerevisiae and S. uvarum strains, respectively. The wild S. cerevisiae beer isolate showed a particular aroma profile due to the highest production of ethyl 4-methylvalerate (lactic and fruity notes), γ-octalactone (coconut), and furfurylthiol (roasted coffee). The latter compound is possibly produced from the pentose phosphate pathway (PPP). Since erythritol, another PPP intermediate was largely produced by this strain.


Assuntos
Saccharomyces , Vinho , Odorantes/análise , Saccharomyces/metabolismo , Saccharomyces cerevisiae/metabolismo , Vinho/análise
13.
Int J Food Microbiol ; 365: 109554, 2022 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-35093767

RESUMO

Interest in the use of non-conventional yeasts in wine fermentation has been increased in the last years in the wine sector. The main objective of this manuscript was to explore the aromatic diversity produced by wild and non-wine strains of S. cerevisiae, S. eubayanus, S. kudriavzevii, and S. uvarum species in young and bottle-aged Tempranillo wines as well as evaluate their fermentation capacity and the yield on ethanol, glycerol, and organic acids, that can contribute to diminishing the effects of climate change on wines. S. uvarum strain U1 showed the highest ability to release or de novo produce monoterpenes, such as geraniol and citronellol, whose values were 1.5 and 3.5-fold higher than those of the wine S. cerevisiae strain. We found that compared to the normal values for red wines, ß-phenylethyl acetate was highly synthesized by U1 and E1 strains, achieving 1 mg/L. Additionally, after aging, wines of S. eubayanus strains contained the highest levels of this acetate. Malic acid was highly degraded by S. kudriavzevii yeasts, resulting in the highest yields of lactic acid (>5-fold) and ethyl lactate (>2.8-fold) in their wines. In aged wines, we observed that the modulating effects of yeast strain were very high in ß-ionone. S. uvarum strains U1 and BMV58 produced an important aging attribute, ethyl isobutyrate, which was highly enhanced during the aging. Also, the agave S. cerevisiae strain develops an essential aroma after aging, reaching the highest ethyl leucate contents. According to the results obtained, the use of wild non-wine strains of S. cerevisiae and strains of the cryotolerant species S. eubayanus, S. kudriavzevii, and S. uvarum in Tempranillo wine fermentation increase the aroma complexity. In addition, wines from S. kudriavzevii strains had twice additional glycerol, those from S. uvarum 4-fold more succinic acid, while wines from wild strains yielded 1% v/v less ethanol which may solve wine problems associated with climate change.


Assuntos
Saccharomyces , Vitis , Vinho , Fermentação , Odorantes/análise , Saccharomyces cerevisiae , Vinho/análise
14.
Angew Chem Int Ed Engl ; 60(50): 26346-26350, 2021 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-34664770

RESUMO

The Diels-Alder reaction is one of the most popular reactions in organic chemistry. However, its use in the field of on-surface synthesis is hampered by the spatial restrictions of this cycloaddition reaction. Herein we selected a cyclic strained triyne to demonstrate an on-surface hexadehydro-Diels-Alder reaction in a single molecule. The reaction was studied in detail by means of atomic force microscopy (AFM) with CO-functionalized tips. Our results pave the way to use this iconic pericyclic reaction for on-surface synthesis, introducing the concept of atom economy in the field.

15.
Org Lett ; 23(19): 7376-7380, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34515492

RESUMO

The reaction of 2-(trimethylsilyl)thiophen-3-yl triflate with CsF in the presence of 2,3,4,5-tetraphenylcyclopentadienone affords 4,5,6,7-tetraphenylbenzo[b]thiophene, as it would be expected from the hypothesized generation and trapping of 2-thiophyne. However, a detailed experimental and computational study discards the intermediacy of this elusive 5-membered hetaryne. Instead, a complex mechanism involving the generation of an intermediate ketocarbene, which adds to the cyclopentadienone to give an isolable tricyclic intermediate, followed by thermal rearrangements, is proposed.

17.
Artigo em Inglês | MEDLINE | ID: mdl-34069229

RESUMO

The procedure developed by the European Joint Action CHRODIS PLUS (JAC+) to transfer and implement good practices from one setting to another was tested in the context of a workplace health promotion good practice identified in the Region of Lombardy (Italy) and transferred and implemented in two organisations in Andalusia (Spain). This article provides a detailed account on how the JAC+ implementation methodology, which included the use of the SQUIRE (Standards for QUality Improvement Reporting Excellence) guidelines, was applied. It offers a practical overview for the uptake of this methodology and of the good practice itself. The account of how this systematic and rigorous implementation reporting model was applied can be of value to those with an interest in workplace health and in the transfer of good practice and implementation sciences.


Assuntos
Saúde Ocupacional , Local de Trabalho , Promoção da Saúde , Itália , Melhoria de Qualidade , Espanha
18.
Clin Ther ; 43(5): e86-e102, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33812699

RESUMO

PURPOSE: We aimed to elucidate the influence on analgesic effect of genetic polymorphisms in enzymes responsible for biotransformation of tramadol and ibuprofen or other possible genes involved in their mechanism of action. METHODS: The study population comprised 118 patients from a multicenter, randomized, double-blind, placebo-controlled, Phase III clinical trial that assessed the analgesic efficacy and tolerability of a single dose of ibuprofen (arginine)/tramadol 400/37.5 mg compared with ibuprofen arginine 400 mg alone, tramadol 50 mg alone, and placebo in patients with moderate to severe pain after dental surgery. We analyzed 32 polymorphisms in the cytochrome P450 (CYP) enzymes COMT, ABCB1, SLC22A1, OPRM1, and SLC22A1. FINDINGS: We did not find any statistically significant difference among CYP2C9 phenotypes related to ibuprofen response, although CYP2C9 poor metabolizers had a longer effect (higher pain relief at 6 hours). Likewise, we did not find any statistically significant difference among PTGS2 genotypes, contradicting previously publications. IMPLICATIONS: There was not a clear effect of CYP2D6 phenotype on tramadol response, although CYP2D6 poor metabolizers had a slower analgesic effect. Concerning the transport of CYP2D6, we observed a better response in individuals carrying ABCB1 mutated alleles, which might correlate with higher tramadol plasma levels. Finally, we found a statistically significant better response in patients carrying the OPRM1 A118G G allele, which contradicts the previous reports. Measuring the active metabolite O-desmethyl-tramadol formation would be of great importance to better evaluate this association because O-desmethyl-tramadol has a higher µ-opioid receptor affinity compared with the parent drug. EudraCT.ema.europa.eu identifier: 2013-004637-33.


Assuntos
Tramadol , Analgésicos Opioides , Método Duplo-Cego , Humanos , Ibuprofeno/uso terapêutico , Dor , Dor Pós-Operatória/tratamento farmacológico , Dor Pós-Operatória/genética , Polimorfismo Genético/genética
19.
Phys Chem Chem Phys ; 23(18): 10845-10851, 2021 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-33908516

RESUMO

The on-surface synthesis of non-planar nanographenes is a challenging task. Herein, with the aid of bond-resolving scanning tunneling microscopy (BRSTM) and density functional theory (DFT) calculations, we present a systematic study aiming at the fabrication of corannulene-based nanographenes via intramolecular cyclodehydrogenation on a Au(111) surface. The formation of non-planar targeted products is confirmed to be energetically unfavorable compared to the formation of planar/quasi-planar undesired competing monomer products. In addition, the activation of intermolecular coupling further inhibits the formation of the final targeted product. Although it was not possible to access the corannulene moiety by means of on-surface synthesis, partial cyclodehydrogenation of the molecular precursors was demonstrated.

20.
J Vis Exp ; (169)2021 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-33749671

RESUMO

On-surface synthesis has recently been regarded as a promising approach for the generation of new molecular structures. It has been particularly successful in the synthesis of graphene nanoribbons, nanographenes and intrinsically reactive and instable, yet attractive species. It is based on the combination of solution chemistry aimed at preparation of appropriate molecular precursors for further ultra-high vacuum surface assisted transformations. This approach also owes its success to an incredible development of characterization techniques, such as scanning tunneling/atomic force microscopy and related methods, which allow detailed, local characterization at atomic scale. While the surface-assisted synthesis can provide molecular nanostructures with outstanding precision, down to single atoms, it suffers from basing on metallic surfaces and often limited yield. Therefore, the extension of the approach away from metals and the struggle to increase productivity seem to be significant challenges toward wider applications. Herein, we demonstrate the on-surface synthesis approach for generation of non-planar nanographenes, which are synthesized through a combination of solution chemistry and sequential surface-assisted processes, together with the detailed characterization by scanning probe microscopy methods.


Assuntos
Grafite/química , Microscopia de Força Atômica/métodos , Nanoestruturas/química , Monóxido de Carbono/química , Ouro/química , Grafite/síntese química , Hidrogenação , Nanoestruturas/ultraestrutura , Porosidade , Soluções , Análise Espectral , Propriedades de Superfície , Vácuo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA