24 research outputs found
Technostress, Career Commitment, Satisfaction with Life, and Work-Family Interaction Among Workers in Information and Communication Technologies
Technostress occurs when individuals experience negative psychosocial effects of technology usage and also demonstrate negative valence associated with ICT use. It is composed of four dimensions (Disbelief, Fatigue, Anxiety, and Ineffectiveness), which describe two aspects of technostress (Technoanxiety and Technofatigue). This study aimed to investigate the relation between technostress dimensions, career commitment, life satisfaction, and work-family interactions among ICT professionals. Variables including gender, age and length of employment were also considered. The sample was composed of 234 Brazilian individuals. It was found that work-family and family-work conflicts were associated with increased technofatigue and tecnoanxiety, and decreased career resilience. Age and gender differences were also identified, which emphasizes the role of organizations and the society in what refers to the scope of this study to reduce inequalities in workplace and to support better preventive actions
Amorphous WO3 as transparent conductive oxide in the near-IR
The demand for transparent conductive films (TCFs) is dramatically increasing. In this work tungsten oxide (WO3-x) is studied as a possible option additional to the existed TCFs. We introduce WO3-x thin films fabricated by a non-reactive magnetron RF-sputtering process at room temperature, followed by thermal annealing in dry air. Films are characterized morphologically, structurally, electrically, optically, and dielectrically. Amorphous WO3-x thin films are shown to be ntype conductive while the transparency extends to the near-IR. By evaluating a figure of merit for transparent-conductive performance and comparing to some most-widely used TCFs, WO3-x turns out to outperform in the near-IR optical range
Esplenectomia: perfil epidemiológico, indicações e complicações pós-operatórias em hospital do Rio Grande do Sul
Objetivo: descrever o perfil epidemiológico, as indicações e complicações pós-operatórias de pacientes submetidos à esplenectomia. Método: trata-se de um estudo transversal, realizado por meio de coleta de dados em prontuários de pacientes submetidos a esplenectomia entre 2015 e 2019 em um hospital terciário. Resultados: a amostra foi composta por 57 pacientes, com idade média de 33,4 anos (+-19,9), a maioria crianças/adolescentes (33,3%), do sexo masculino (57,9%), solteiros (57,9%), de religião católica (80,7%), atuantes no setor terciário do mercado de trabalho (43,9%), ensino fundamental incompleto (42,1%), procedentes de outras cidades, que não Passo Fundo (66,7%). A principal indicação para esplenectomia foi o acometimento de Púrpura Trombocitopênica Idiopática (33,3%) e a principal alteração pós-operatória associada foi a leucocitose persistente (25%). Conclusões: a esplenectomia é mais comum em crianças/adolescentes, sexo masculino e tem como principal indicação o Púrpura Trombocitopênica Idiopática conforme maioria dos estudo e apresenta alterações pouco frequentemente e, quando presentes, estão relacionadas a leucocitose persistente
Lanthanide-Organic Capsules: luminescent helicates and mesocates as chiral and temperature sensors
Il design e il controllo del processo di self-assembly di capsule a base di lantanidi \ue8 uno stimolante ambito di ricerca nello sviluppo della chimica supramolecolare. Allo stesso tempo, la possibilit\ue0 di costruire architetture con specifiche propriet\ue0 strutturali e funzionali conferisce a questi sistemi un promettente futuro nel campo dei materiali funzionali luminescenti. A questo scopo, questa tesi riporta la progettazione, la sintesi e la caratterizzazione di nuove capsule metallorganiche a base di lantanidi (LOC).
I sistemi sviluppati sono capsule dimeriche, classificate come elicati (M o P, chirali) o mesocati (achirali). La formula generale \ue8 [Ln2(L)4]2- dove il centro metallico \ue8 uno ione lantanoideo (Ln3+ = La3+, Eu3+, Tb3+, Gd3+) e i leganti L sono tre diversi bis-\u3b2-dichetoni. L'unit\ue0 chelante, in grado di sensibilizzare l'emissione di Eu3+ e Tb3+, \ue8 la stessa per tutti e tre i leganti e corrisponde al benzoiltrifluoroacetone, mentre i diversi spacer centrali (gruppo carbammato, fenilico o metilenico) permettono di ottenere sistemi con diverse propriet\ue0 strutturali (dimensioni e forma). La formazione dei LOC, confermata da diverse tecniche di analisi (NMR, spettrometria di massa e XRD su cristallo singolo), evidenzia la presenza di: i) interazioni host-guest e ii) propriet\ue0 di chiralit\ue0 supramolecolare, che, insieme alle peculiari caratteristiche di luminescenza degli ioni Ln3+, possono essere sfruttate sia per il sensing chimico (riconoscimento guest chirali) che per quello fisico (termometria di luminescenza).
In primo luogo, viene presentato lo studio delle propriet\ue0 strutturali e l'applicazione dei LOC come sensori chirali. I sistemi sono stati studiati attraverso calcoli DFT per comprendere i fattori che governano la chiralit\ue0 supramolecolare (flessibilit\ue0 del legante, incapsulamento di un guest (chirale o meno) e dimensione del guest) e poi testati come sensori chimici. \uc8 interessante notare che i LOC, in presenza degli enantiomeri dell\u2019\u3b1-metilcolina, mostrano sia dicroismo circolare che luminescenza circolarmente polarizzata indotta, confermando la loro efficacia nel riconoscimento del guest chirale.
Prima di procedere con gli studi di termometria, \ue8 stata investigata, tramite ESI-MS, la cinetica dello scambio di ioni metallici tra capsule omometalliche. Infatti, poich\ue9 i termometri molecolari (TM) raziometrici vengono preparati miscelando [Eu2(L)4]2- e [Tb2(L)4]2- in diversi rapporti Eu3+/Tb3+, non si pu\uf2 escludere la formazione di capsule eterometalliche.
Nella seconda parte vengono discussi due aspetti principali della termometria di luminescenza, ovvero lo sviluppo di: i) un modello in grado di prevedere e interpretare le propriet\ue0 termometriche dei TM e ii) nuovi termometri luminescenti basati su ioni Ln3+.
Il modello predittivo permette di identificare e pesare i fenomeni coinvolti nella modulazione della luminescenza dell\u2019europio, utilizzando parametri (sperimentali o calcolati) facilmente ottenibili. Ad oggi, sono stati inclusi con successo tre possibili canali di disattivazione: due termini competitivi relativi al metallo (back energy transfer metallo-legante e quenching multifononico), e un terzo termine relativo al legante per tenere conto del processo di disattivazione non-radiativa del tripletto.
Infine, i LOC di Eu3+ e Tb3+, grazie alle loro propriet\ue0 di luminescenza, sono stati impiegati per sviluppare sia termometri luminescenti a singola emissione (Eu3+ e Tb3+) sia termometri raziometrici autocalibranti (misti, Eu3+/Tb3+), mostrando una buona sensibilit\ue0 termica relativa (Sr massimo 3.2 \u2013 5.5 %\ub7K-1) e un ampio (oltre 150 K) intervallo di applicabilit\ue0 (assunto come intervallo di temperatura in cui il valore di Sr \ue8 superiore a 1 %\ub7K-1). Inoltre, la presenza di due emettitori (Tb3+, verde e Eu3+, rosso), le cui intensit\ue0 di emissione dipendono dalla temperatura, apre la strada all'impiego di questi sistemi anche come sensori colorimetrici di temperatura
Antenna triplet DFT calculations to drive the design of luminescent Ln3+ complexes
Density functional theory-based methods have been exploited to look into the structural, vibrational and electronic properties of antenna ligands, all of them being crucial factors for the reliable design of customized luminescent lanthanide (Ln3+) complexes. The X-ray structures, UV-Vis absorption spectra and triplet (T1) energies of three novel \u3b2-diketone ligands with a thienyl group and naphthyl (L1), phenanthryl (L2), and pyrenyl (L3) polycyclic aromatic hydrocarbons as substituents have been modelled. Vibronic progressions provide a strong contribution to the L1 and L2 absorption spectra, while the L3 absorption spectrum needs the assumption of different conformational isomers in solution. T1 energies have been estimated either through the vertical- or the adiabatic-transition approach. The comparison with the phosphorescence spectra of Gd3+ complexes allowed us to infer that the latter approach is the most suitable one, in particular when sizable ligands are involved. Results obtained for the isolated antennas can be directly compared with those of the corresponding Ln3+ complexes, due to the unanimously accepted assumption that the excitation is ligand-centred
Dynamic lanthanide exchange between quadruple-stranded cages: the effect of ionic radius differences on kinetics and thermodynamics
Seven different [Ln2L4]2− (Ln = La, Nd, Eu, Tb, Er, Tm and Lu) lanthanide-based quadruple-stranded helicates are here reported and transmetalation among the pre-assembled cages is studied. Combining two homonuclear helicates, [LnA2L4]2− and [LnB2L4]2−, leads to the formation of a mixture of homo- and heteronuclear systems due to ion exchange. This dynamic behaviour is studied by electrospray ionization mass spectrometry (ESI-MS) both qualitatively and quantitatively, allowing one to gain information on the thermodynamics and on the kinetics of the process. The rate of the Ln ion exchange is strongly correlated with the difference in the lanthanide effective ionic radius (ΔEIR). Upon increasing the ΔEIR, the kinetic constants grow exponentially: from the minimum to the maximum value of the ΔEIR, the kinetic constants of the forward and backward reactions increase by three orders of magnitude. In contrast, the equilibrium constant is the same for all the [LnA2L4]2−/[LnB2L4]2− couples, showing that the transmetalation is mainly entropy driven towards a statistical mixture and not affected by the ΔEIR
Dynamic lanthanides exchange between quadruple-stranded cages: effect of ionic radius differences on kinetics and thermodynamics
Seven different [Ln2L4]2− (Ln = La, Nd, Eu, Tb, Er, Tm and Lu) lanthanide-based quadruple-stranded helicates are here reported and transmetalation among pre-assembled cages was studied. Combining two homonuclear helicates [LnA2L4]2− and [LnB2L4]2− leads to the formation of a mixture of homo- and heteronuclear systems due to ion exchange. This dynamic behaviour was studied by electrospray ionization mass spectrometry (ESI-MS) both qualitatively and quantitatively allowing to gain information on the thermodynamics as well as on the kinetics of the process. The rate of the Ln ion exchange is strongly dependent on the difference in lanthanide effective ionic radius (ΔEIR). Upon increasing ΔEIR, the kinetic constants grow exponentially: from the minimum to the maximum value of ΔEIR, the kinetic constants of the forward and backward reactions increase by three orders of magnitude. On the contrary, the equilibrium constant is the same for all the [LnA2L4]2−/[LnB2L4]2− couples, showing that the transmetalation is mainly entropy-driven towards a statistical mixture and not affected by ΔEIR
Easy but not straightforward: Base and solvent effect on the synthesis of luminescent europium 1,3-di(thien-2-yl)propane-1,3-dionate coordination complexes
Reaction between EuCl3 and the ligand 1,3-di(thien-2-yl)propane-1,3-dione (L) leads to luminescent coordination compounds [EuL3(EtOH)2] (1), [EuL2(i-PrOH)4]Cl (2) and [EuL3(i-PrOH)2] (3), isolated as single crystals in high yield (70%–95%). The Eu/β-diketonate ratio is tuned from 1:2 to 1:3 through the variation of the alcoholic solvent (ethanol and isopropanol) or the base (pyridine and NaOH). In all compounds, Eu3+ ions are eight-coordinated, and in 2, the molecules are arranged in an H-bond supported supramolecular 1D chain. These compositional and structural differences are reflected also on the absorption and emission properties. </jats:p
Di(N-heterocyclic carbene) gold(III) imidate complexes obtained by oxidative addition of N-halosuccinimides
none6nononeBaron, Marco*; Dalla Tiezza, Marco; Carlotto, Alice; Tubaro, Cristina; Graiff, Claudia; Orian, LauraBaron, Marco; Dalla Tiezza, Marco; Carlotto, Alice; Tubaro, Cristina; Graiff, Claudia; Orian, Laur