Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 22
Filtrar
1.
Acta Microbiol Immunol Hung ; 70(1): 7-10, 2023 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-36753298

RESUMO

The high demand for COVID-19 diagnosis overwhelmed reference hospitals. Regional laboratories had to incorporate molecular technology to respond to the emergency. This work described the implementation of molecular diagnostic tools and the detection of SARS-CoV-2, in a regional hospital with no previous experience, from October 2020 to March 2022. The laboratory structure was significantly modified. The staff grew from 3 to 4 clinical microbiologists, and from 7 to 17 laboratory technicians to provide 24/7 coverage. A total of 144,442 samples were processed during the period of study. The highest peaks were reached in July 2021 with 25,285 samples processed, and between December 2021 and January 2022, with 32,245. COVID-19 pandemic has represented not only the challenge, but the opportunity to introduce Nucleic Acid Amplification Techniques (NAAT) in inexperienced laboratories. These secondary settings have shown an extraordinary ability to adapt and cannot be left behind in the progress of diagnostic techniques.


Assuntos
COVID-19 , Humanos , SARS-CoV-2 , Laboratórios , Teste para COVID-19 , Espanha , Pandemias , Técnicas de Laboratório Clínico/métodos
2.
Adv Funct Mater ; 30(28): 2000228, 2020 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-32684906

RESUMO

2D hybrid perovskites (2DP) are versatile materials, whose electronic and optical properties can be tuned through the nature of the organic cations (even when those are seemingly electronically inert). Here, it is demonstrated that fluorination of the organic ligands yields glassy 2DP materials featuring long-lived correlated electron-hole pairs. Such states have a marked charge-transfer character, as revealed by the persistent Stark effect in the form of a second derivative in electroabsorption. Modeling shows that electrostatic effects associated with fluorination, combined with the steric hindrance due to the bulky side groups, drive the formation of spatially dislocated charge pairs with reduced recombination rates. This work enriches and broadens the current knowledge of the photophysics of 2DP, which will hopefully guide synthesis efforts toward novel materials with improved functionalities.

3.
Chemistry ; 26(48): 11039-11047, 2020 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-32608525

RESUMO

Three novel donor-π-bridge-donor (D-π-D) hole-transporting materials (HTMs) featuring triazatruxene electron-donating units bridged by different 3,4-ethylenedioxythiophene (EDOT) π-conjugated linkers have been synthesized, characterized, and implemented in mesoporous perovskite solar cells (PSCs). The optoelectronic properties of the new dumbbell-shaped derivatives (DTTXs) are highly influenced by the chemical structure of the EDOT-based linker. Red-shifted absorption and emission and a stronger donor ability were observed in passing from DTTX-1 to DTTX-2 due to the extended π-conjugation. DTTX-3 featured an intramolecular charge transfer between the external triazatruxene units and the azomethine-EDOT central scaffold, resulting in a more pronounced redshift. The three new derivatives have been tested in combination with the state-of-the-art triple-cation perovskite [(FAPbI3 )0.87 (MAPbBr3 )0.13 ]0.92 [CsPbI3 ]0.08 in standard mesoporous PSCs. Remarkable power conversion efficiencies of 17.48 % and 18.30 % were measured for DTTX-1 and DTTX-2, respectively, close to that measured for the benchmarking HTM spiro-OMeTAD (18.92 %), under 100 mA cm-2 AM 1.5G solar illumination. PSCs with DTTX-3 reached a PCE value of 12.68 %, which is attributed to the poorer film formation in comparison to DTTX-1 and DTTX-2. These PCE values are in perfect agreement with the conductivity and hole mobility values determined for the new compounds and spiro-OMeTAD. Steady-state photoluminescence further confirmed the potential of DTTX-1 and DTTX-2 for hole-transport applications as an alternative to spiro-OMeTAD.

4.
J Org Chem ; 85(1): 224-233, 2020 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-31760753

RESUMO

Three hole-transporting materials (HTMs) were prepared following a straightforward synthetic route by cross-linking arylamine-based ligands with a simple thieno[3,2-b]thiophene (TbT) core. The novel HTMs were fully characterized with standard techniques to gain insight into their optical and electrochemical properties and were incorporated in solution-processed mesoporous (FAPbI3)0.85(MAPbBr3)0.15 perovskite-based solar cells. The similar molecular structure of the synthesized HTMs was leveraged to investigate the role that the bridging units between the conjugated TbT core and the peripheral arylamine units plays on their properties and thereby on the photovoltaic response. A remarkable power conversion efficiency exceeding 18% was achieved for one of the TbT derivatives, which was slightly higher than the value measured for the benchmark spiro-OMeTAD.

5.
Chem Soc Rev ; 47(23): 8541-8571, 2018 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-30283961

RESUMO

Photovoltaic solar cells based on perovskites have come to the forefront in science by achieving exceptional power conversion efficiencies (PCEs) in less than a decade of research. This "still young" generation of solar cells is currently rivalling, in PCEs, well-established technologies, such as cadmium telluride (CdTe) and silicon. Further improvements in device stability by means of innovative materials are yet to come, with technology becoming closer to meeting the market requirements. Emerging from this groundbreaking discovery, a great number of charge transporting materials have flourished, which is particularly true for hole transporting materials (HTMs). The huge number of molecules prepared stem from design and engineering of a wide variety of new and also chemically modified old molecules where organic synthesis has played a fundamental role. In this review, the contribution of chemistry through those synthetic protocols used for producing new and innovative HTMs from relatively simple organic molecules is presented in a rational and systematic manner. The variety and impact of synthetic strategies followed, the structure-property relationship and stability, conductivity and device performance are highlighted from a chemical viewpoint.

6.
Angew Chem Int Ed Engl ; 55(21): 6270-4, 2016 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-27061436

RESUMO

New star-shaped benzotrithiophene (BTT)-based hole-transporting materials (HTM) BTT-1, BTT-2 and BTT-3 have been obtained through a facile synthetic route by crosslinking triarylamine-based donor groups with a benzotrithiophene (BTT) core. The BTT HTMs were tested on solution-processed lead trihalide perovskite-based solar cells. Power conversion efficiencies in the range of 16 % to 18.2 % were achieved under AM 1.5 sun with the three derivatives. These values are comparable to those obtained with today's most commonly used HTM spiro-OMeTAD, which point them out as promising candidates to be used as readily available and cost-effective alternatives in perovskite solar cells (PSCs).

7.
Med Clin (Barc) ; 160(8): 341-346, 2023 04 21.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-36623986

RESUMO

INTRODUCTION: Calcitonine Gen-Related Peptide (CGRP) established a revolution in migraine pathophysiology knowledge and has led to the development of new drugs specifically targeting this disease. METHODS: We present a prospective study in which 63 episodic and chronic migraine patients have been treated with anti-CGRP monoclonal antibodies describing their efficacy, security and relapses after their interruption. Response predictors have been analyzed such they can help us to create a better treatment plan. RESULTS: Average age was 48.3 ± 11.81 years old, 84.1% of them being women. The average was of 15.59 migraine days per month (MDM). 63.5% of all patients suffered chronic migraine. The initial dose of Erenumab in all patient was 70 mg subcutaneous. This was increased to 140 mg in 47.6% of the patients. An MDM reduction between 49.85% and 59.53% was obtained within three to twelve months from the start of treatment. Constipation was present in 17.5% of the patients and 4.8% suffered injection site reaction. The treatment was changed to Galcanezumab in 17.9% of the patients. After interrupting the treatment, 23 patients relapsed with a good response on reintroduction of the treatment. It was not possible to establish a clear response predictor, however a statistically significant increase in the number of days of improvement was observed with more MDM at baseline level (p = 0.002). CONCLUSIONS: Anti-CGRP monoclonal antibodies are effective, safe, and well tolerated drugs. We have observed that their discontinuation, in some cases can lead to frequent and early relapses so we strongly recommend to extend the treatment in those patients with a higher MDM.


Assuntos
Transtornos de Enxaqueca , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doença Crônica , Transtornos de Enxaqueca/tratamento farmacológico , Transtornos de Enxaqueca/prevenção & controle , Estudos Prospectivos , Peptídeo Relacionado com Gene de Calcitonina/imunologia
8.
Nat Commun ; 14(1): 2426, 2023 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-37105984

RESUMO

Hybrid perovskites have emerged as a promising material candidate for exciton-polariton (polariton) optoelectronics. Thermodynamically, low-threshold Bose-Einstein condensation requires efficient scattering to the polariton energy dispersion minimum, and many applications demand precise control of polariton interactions. Thus far, the primary mechanisms by which polaritons relax in perovskites remains unclear. In this work, we perform temperature-dependent measurements of polaritons in low-dimensional perovskite wedged microcavities achieving a Rabi splitting of [Formula: see text] = 260 ± 5 meV. We change the Hopfield coefficients by moving the optical excitation along the cavity wedge and thus tune the strength of the primary polariton relaxation mechanisms in this material. We observe the polariton bottleneck regime and show that it can be overcome by harnessing the interplay between the different excitonic species whose corresponding dynamics are modified by strong coupling. This work provides an understanding of polariton relaxation in perovskites benefiting from efficient, material-specific relaxation pathways and intracavity pumping schemes from thermally brightened excitonic species.

9.
Adv Sci (Weinh) ; 9(19): e2200407, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35604199

RESUMO

On-surface synthesis has recently emerged as a powerful strategy to design conjugated polymers previously precluded in conventional solution chemistry. Here, an N-containing pentacene-based precursor (tetraazapentacene) is ex-professo synthesized endowed with terminal dibromomethylene (:CBr2 ) groups to steer homocoupling via dehalogenation on metallic supports. Combined scanning probe microscopy investigations complemented by theoretical calculations reveal how the substrate selection drives different reaction mechanisms. On Ag(111) the dissociation of bromine atoms at room temperature triggers the homocoupling of tetraazapentacene units together with the binding of silver adatoms to the nitrogen atoms of the monomers giving rise to a N-containing conjugated coordination polymer (P1). Subsequently, P1 undergoes ladderization at 200 °C, affording a pyrrolopyrrole-bridged conjugated polymer (P2). On Au(111) the formation of the intermediate polymer P1 is not observed and, instead, after annealing at 100 °C, the conjugated ladder polymer P2 is obtained, revealing the crucial role of metal adatoms on Ag(111) as compared to Au(111). Finally, on Ag(100) the loss of :CBr2 groups affords the formation of tetraazapentacene monomers, which coexist with polymer P1. Our results contribute to introduce protocols for the synthesis of N-containing conjugated polymers, illustrating the selective role of the metallic support in the underlying reaction mechanisms.

10.
JACS Au ; 2(1): 136-149, 2022 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-35098230

RESUMO

Lead-free perovskites are attracting increasing interest as nontoxic materials for advanced optoelectronic applications. Here, we report on a family of silver/bismuth bromide double perovskites with lower dimensionality obtained by incorporating phenethylammonium (PEA) as an organic spacer, leading to the realization of two-dimensional double perovskites in the form of (PEA)4AgBiBr8 (n = 1) and the first reported (PEA)2CsAgBiBr7 (n = 2). In contrast to the situation prevailing in lead halide perovskites, we find a rather weak influence of electronic and dielectric confinement on the photophysics of the lead-free double perovskites, with both the 3D Cs2AgBiBr6 and the 2D n = 1 and n = 2 materials being dominated by strong excitonic effects. The large measured Stokes shift is explained by the inherent soft character of the double-perovskite lattices, rather than by the often-invoked band to band indirect recombination. We discuss the implications of these results for the use of double perovskites in light-emitting applications.

11.
ACS Appl Mater Interfaces ; 13(24): 28214-28221, 2021 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-34105947

RESUMO

A decade after the report of the first efficient perovskite-based solar cell, development of novel hole-transporting materials (HTMs) is still one of the main topics in this research field. Two of the main advance vectors of this topic lie in obtaining materials with enhanced hole-extracting capability and in easing their synthetic cost. The use of anthra[1,9-bc:5,10-b'c']dithiophene (ADT) as a flat π-conjugated frame for bearing arylamine electroactive moieties allows obtaining two novel highly efficient HTMs from very cheap precursors. The solar cells fabricated making use of the mixed composition (FAPbI3)0.85(MAPbBr3)0.15 perovskite and the novel ADT-based HTMs show power conversion efficiencies up to 17.6% under 1 sun illumination compared to the 18.1% observed when using the benchmark compound 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD). Detailed density functional theory calculations allow rationalization of the observed opto-electrochemical properties and predict a flat molecular structure with a low reorganization energy that supports the high conductivity measured for the best-performing HTM.

12.
BMC Infect Dis ; 10: 181, 2010 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-20569435

RESUMO

BACKGROUND: Altered blood glucose concentration is commonly observed in patients with sepsis, even among those without hypoglycemic treatments or history of diabetes mellitus. These alterations in blood glucose are potentially detrimental, although the precise relationship with outcome in patients with bacteremia has not been yet determined. METHODS: A retrospective cohort study design for analyzing patients with Gram negative rod bacteremia was employed, with the main outcome measure being in-hospital mortality. Patients were stratified in quintiles accordingly deviation of the blood glucose concentration from a central value with lowest mortality. Cox proportional-hazards regression model was used for determining the relationship of same day of bacteremia blood glucose and death. RESULTS: Of 869 patients identified 63 (7.4%) died. Same day of bacteremia blood glucose concentration had a U-shaped relationship with in-hospital mortality. The lowest mortality (2%) was detected in the range of blood glucose concentration from 150 to 160 mg/dL. Greater deviation of blood glucose concentration from the central value of this range (155 mg/dL, reference value) was directly associated with higher risk of death (p = 0.002, chi for trend). The low-risk group (quintile 1) had a mortality of 3.3%, intermediate-risk group (quintiles 2, 3 and 4) a mortality of 7.1%, and the high-risk group (quintile 5) a mortality of 12.05%. In a multivariable Cox regression model, the hazard ratio for death among patients in the intermediate-risk group as compared with that in the low risk group was 2.88 (95% confidence interval, 1.01 to 8.18; P = 0.048), and for the high risk group it was 4.26 (95% confidence interval, 1.41 to 12.94; P = 0.01). CONCLUSIONS: Same day of bacteremia blood glucose concentration is related with outcome of patients with Gram-negative rod bacteremia. Lowest mortality is detected in patients with blood glucose concentration in an interval of 150-160 mg/dL. Deviations from these values are associated with an increased risk of death.


Assuntos
Bacteriemia/complicações , Glicemia/análise , Infecções Comunitárias Adquiridas/complicações , Infecções por Bactérias Gram-Negativas/complicações , Bacilos Gram-Negativos Anaeróbios Facultativos/isolamento & purificação , Idoso , Idoso de 80 Anos ou mais , Bacteriemia/microbiologia , Bacteriemia/mortalidade , Estudos de Coortes , Infecções Comunitárias Adquiridas/microbiologia , Infecções Comunitárias Adquiridas/mortalidade , Feminino , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/mortalidade , Humanos , Masculino , Prognóstico , Estudos Retrospectivos , Resultado do Tratamento
13.
Front Chem ; 8: 66, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32117889

RESUMO

Two-dimensional (2D) hybrid organic-inorganic perovskites have recently attracted the attention of the scientific community due to their exciting optical and electronic properties as well as enhanced stability upon exposure to environmental factors. In this work, we investigate 2D perovskite layers with a range of organic cations and report on the Achilles heel of these materials-their significant degradation upon exposure to vacuum. We demonstrate that vacuum exposure induces the formation of a metallic lead species, accompanied by a loss of the organic cation from the perovskite. We investigate the dynamics of this reaction, as well as the influence of other factors, such as X-ray irradiation. Furthermore, we characterize the effect of degradation on the microstructure of the 2D layers. Our study highlights that despite earlier reports, 2D perovskites may exhibit instabilities, the chemistry of which should be identified and investigated in order to develop suitable mitigation strategies.

14.
Front Chem ; 7: 946, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-32064245

RESUMO

Low-dimensional hybrid perovskites have triggered significant research interest due to their intrinsically tunable optoelectronic properties and technologically relevant material stability. In particular, the role of the organic spacer on the inherent structural and optical features in two-dimensional (2D) perovskites is paramount for material optimization. To obtain a deeper understanding of the relationship between spacers and the corresponding 2D perovskite film properties, we explore the influence of the partial substitution of hydrogen atoms by fluorine in an alkylammonium organic cation, resulting in (Lc)2PbI4 and (Lf)2PbI4 2D perovskites, respectively. Consequently, optical analysis reveals a clear 0.2 eV blue-shift in the excitonic position at room temperature. This result can be mainly attributed to a band gap opening, with negligible effects on the exciton binding energy. According to Density Functional Theory (DFT) calculations, the band gap increases due to a larger distortion of the structure that decreases the atomic overlap of the wavefunctions and correspondingly bandwidth of the valence and conduction bands. In addition, fluorination impacts the structural rigidity of the 2D perovskite, resulting in a stable structure at room temperature and the absence of phase transitions at a low temperature, in contrast to the widely reported polymorphism in some non-fluorinated materials that exhibit such a phase transition. This indicates that a small perturbation in the material structure can strongly influence the overall structural stability and related phase transition of 2D perovskites, making them more robust to any phase change. This work provides key information on how the fluorine content in organic spacer influence the structural distortion of 2D perovskites and their optical properties which possess remarkable importance for future optoelectronic applications, for instance in the field of light-emitting devices or sensors.

16.
Curr Zool ; 64(5): 603-613, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30323839

RESUMO

Mountains imply enormous environmental variation, with alpine habitats entailing harsh environments, especially for ectotherms such as lizards. This environmental variability also may imply variation in prey availability. However, little is known about how lizard trophic ecology varies with elevation. In this study, we analyze diet, prey availability, prey selection, and trophic niche width in the lacertid lizard Psammodromus algirus along a 2,200-m elevational gradient in the Sierra Nevada (SE Spain). The analysis of fecal samples has shown that Orthoptera, Formicidae, Hemiptera, Coleoptera, and Araneae are the main prey, although, according to their abundance in pitfall traps, Formicidae and Coleoptera are rejected by the lizard whereas Orthoptera, Hemiptera, and Araneae are preferred. Prey abundance and diversity increase with elevation and diet subtly varies along with the elevational gradient. The consumption of Coleoptera increases with elevation probably as a consequence of the lizard foraging more in open areas while basking. The electivity for Araneae increases with elevation. Araneae are rejected in the lowlands-where they are relatively abundant-whereas, at high elevation, this lizard positively selects them, despite they being less abundant. The lizard trophic niche width expands with elevation due to concomitant greater prey diversity and hence this lizard feeds on more prey types in highlands. Although no sex difference in diet has been found, the trophic niche is broader in females than males. As a whole, alpine lizards show a trophic niche similar to that found at lower elevations, suggesting that P. algirus is well adapted to the harsh environment found in alpine areas.

17.
ChemSusChem ; 10(9): 2023-2029, 2017 05 09.
Artigo em Inglês | MEDLINE | ID: mdl-28296265

RESUMO

A variety of novel chemically modified fullerenes, showing different electron-accepting capabilities, has been synthesized and used to prepare electron transport layer (ETL)-free solar cells based on perovskite/fullerene blends. In particular, isoxazolino[60] fullerenes are proven to be a good candidate for processing blend films with CH3 NH3 PbI3 and obtaining enhanced power conversion efficiency (PCE) ETL-free perovskite solar cells (PSCs), improving the state-of-the-art PCE (i.e., 14.3 %) for this simplified device architecture. A beneficial effect for pyrazolino and methano[60]fullerene derivatives versus pristine [60]/fullerene is also shown. Furthermore, a clear correlation between the LUMO energy level of the fullerene component and the open circuit voltage of the solar cells is found. Apart from the new knowledge on innovative fullerene derivatives for PSCs, the universality and versatility of perovskite/fullerene blend films to obtain efficient ETL-free PSCs is demonstrated.


Assuntos
Compostos de Cálcio/química , Fontes de Energia Elétrica , Elétrons , Fulerenos/química , Óxidos/química , Energia Solar , Titânio/química
18.
Rev Enferm ; 29(4): 33-8, 2006 Apr.
Artigo em Espanhol | MEDLINE | ID: mdl-16724498

RESUMO

The use of the scientific method in research and investigation in nursing requires avoiding subjectivity at all times. Professionals obtain data by means of instruments which must be operative, valid and reliable. The authors develop and verify two instruments: a nine question opinion poll which uses tests and retests, having a 93-40% concordance proportion. A Likert type attitude scale, applying the "t" in Student to 59 initial propositions, obtaining a definitive scale having 7 positive items and 7 negative ones which gave a 95% confidence level of statistical meaning for a bilateral test and which had 22 degrees of liberty. This study took place using a pilot group of 43 nurses, it was a practical shop exercise on research in nursing occurred in the Hospital, organized by the Nursing Administration and taught by the group coordinator.


Assuntos
Atitude , Opinião Pública , Inquéritos e Questionários , Humanos , Pesquisa em Enfermagem
19.
J Phys Chem Lett ; 7(22): 4622-4628, 2016 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-27797214

RESUMO

The use of self-assembled monolayers (SAMs) of fullerene derivatives reduces the hysteresis of perovskite solar cells (PSCs). We have investigated three different fullerene derivatives observing a decrease on hysteresis for all the cases. Several processes can contribute to the hysteresis behavior on PSCs. We have determined that the reduced hysteresis observed for devices with SAMs is produced by a decrease of the capacitive hysteresis. In addition, with an appropriated functionalization, SAMs can increase photocurrent even when no electron selective contact (ESC) is present and a SAM is deposited just on top of the transparent conductive oxide. Appropriated functionalization of the fullerene derivative, as introducing -CN groups, can enhance cell performance and reduce hysteresis. This work paves the way for a future enhancement of PSCs by a tailored design of the fullerene molecules that could actuate as an ESC by themselves.

20.
Chem Commun (Camb) ; 51(73): 13980-2, 2015 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-26246213

RESUMO

We report the synthesis and characterisation of tetra{4-[N,N-(4,4'-dimethoxydiphenylamino)]phenyl}ethene () as an efficient and robust hole transport material for its application in methyl ammonium lead iodide (MAPI) perovskite solar cells. The solar cells show light-to-energy conversion efficiencies as high as 11.0% under standard measurement conditions without the need of additional dopants.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA