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1.
Eur J Clin Pharmacol ; 75(12): 1645-1657, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31511939

RESUMO

PURPOSE: Anticoagulation-associated adverse drug events are common in hospitalised patients and result in morbidity, mortality, increased length of hospital stay and higher costs of care. Many are preventable. We reviewed the literature to identify and assess interventions intended to improve safety or quality anticoagulant prescribing. METHODS: A systematic search of EMBASE, MEDLINE, the Cochrane Library, Pretty Darn Quick-Evidence and Health Systems Evidence was undertaken to identify controlled studies assessing system-level interventions to improve prescribing of oral or parenteral therapeutic anticoagulation for any indication in hospitalised adults. Data were extracted for safety and quality outcomes, with studies grouped by intervention type for meta-analysis and narrative review. RESULTS: Of 10,640 records screened, 19 trials evaluating 12,742 participants were included for analysis. No study specifically evaluated prescribing of low molecular weight heparins (LMWHs) or direct acting oral anticoagulants (DOACs). Our findings suggest that physician-led anticoagulation consultation services may reduce bleeding rates in high-risk patients. On meta-analysis, decision supported warfarin dosing resulted in higher proportion of time with international normalised ratio in therapeutic range (p = 0.0007). Studies of other clinical decision support systems and heparin monitoring systems did not demonstrate improved safety, and quality findings were inconsistent. Systematic education and feedback programs were not efficacious. CONCLUSIONS: There is currently insufficient high-quality evidence to recommend any reviewed intervention, though several warrant closer evaluation. Adequately powered controlled trials assessing safety outcomes and evidence-based quality markers in high-risk patient groups and studies of interventions to improve safety of LMWH and DOAC prescribing are needed.


Assuntos
Anticoagulantes/administração & dosagem , Anticoagulantes/efeitos adversos , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/prevenção & controle , Hemorragia/induzido quimicamente , Hemorragia/prevenção & controle , Heparina de Baixo Peso Molecular/administração & dosagem , Heparina de Baixo Peso Molecular/efeitos adversos , Humanos , Pacientes Internados , Prescrições/estatística & dados numéricos , Ensaios Clínicos Controlados Aleatórios como Assunto
2.
J Clin Child Adolesc Psychol ; 48(5): 790-798, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30052081

RESUMO

Evidence supports the distinctions between forms (relational vs. physical) and functions (proactive vs. reactive) of aggression; however, little research has investigated these two subtype frameworks simultaneously or by teacher-report in early childhood. We examined the factor structures, interrelations, and longitudinal associations of teacher-reported forms and functions of aggression in young children. Preschool and kindergarten students (N = 133; ages 3-6 years; 58.6% male) were rated by their teachers during the spring semester and on two subsequent occasions over the following school year (a three-wave cross-sequential design). Bayesian confirmatory factor analyses and path models were estimated, controlling for covariates and cross-classification of students within classrooms. Correlated two-factor models showed acceptable measurement characteristics for both aggression frameworks. Within and between frameworks, aggression subtypes were highly correlated with one another. Physical aggression showed greater stability than, and was a precursor to, relational aggression, whereas both proactive and reactive aggression were stable and bidirectional. All subtypes-especially reactive and physical aggression-were robustly associated with peer rejection but not with academic performance or depressive symptoms. Results suggest that brief, teacher-reported rating scales can be used to measure forms and functions of aggression during early childhood. However, examination of one framework should elicit questions regarding the other (e.g., to what extent are measures of proactive and reactive aggression capturing physical aggression?), and research following a form-by-function approach may be particularly useful. Given their stability and outcomes, physical, reactive, and proactive aggression may be important targets for screening and intervention in early childhood settings.


Assuntos
Agressão/psicologia , Criança , Pré-Escolar , Feminino , Humanos , Masculino
3.
Child Psychiatry Hum Dev ; 50(6): 883-893, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-30989477

RESUMO

The current cross-sectional study examined whether internalizing (i.e. anxiety and depressive) symptoms and/or emotion dysregulation moderated the association between witnessed community violence and aggressive behavior. Participants were 180 predominantly African American adolescents (62% girls; M age = 15.87 years, SD = 1.19 years) from a high school located in an urban community in the United States. Approximately 95% of adolescents reported having witnessed at least one violent act during their lifetimes, with many endorsing repeated exposure to severe acts of community violence. Results indicated that emotion dysregulation exacerbated the association between witnessed community violence and aggression. A quadratic effect of anxiety symptoms also moderated this association, such that witnessed community violence was linked to aggression at low and high, but not moderate, levels of anxiety symptoms. In contrast, a quadratic effect of depressive symptoms was uniquely related to aggression, regardless of witnessed community violence. Directions for future research and implications for practice are reviewed.


Assuntos
Comportamento do Adolescente , Sintomas Afetivos/epidemiologia , Agressão , Ansiedade/epidemiologia , Negro ou Afro-Americano/estatística & dados numéricos , Depressão/epidemiologia , Exposição à Violência/estatística & dados numéricos , População Urbana/estatística & dados numéricos , Adolescente , Estudos Transversais , Feminino , Humanos , Masculino , Estados Unidos/epidemiologia
4.
Aggress Behav ; 43(5): 450-459, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28217970

RESUMO

The current short-term longitudinal study evaluated whether anxiety symptoms moderated the bidirectional associations between forms (i.e., physical and relational) of aggression and peer victimization over a 1-year period during middle childhood. Participants were 228 predominantly Caucasian children (50.4% boys; M = 8.32 years, SD = .95 years) in the second through fourth grades and their homeroom teachers. Children completed a self-report measure of anxiety symptoms at Time 1. Peer victimization was assessed using self-reports at Time 1 and approximately 1 year later (Time 2), and teachers provided ratings of children's aggressive behavior at both time points. A series of cross-lagged path analysis models indicated that high (+1 SD) initial levels of anxiety symptoms exacerbated the prospective link from Time 1 relational aggression to Time 2 peer victimization; conversely, when initial levels of anxiety symptoms were low (-1 SD), relational aggression predicted lower levels of subsequent peer victimization. Time 1 peer victimization was also found to predict lower levels of Time 2 physical aggression when initial levels of anxiety symptoms were low, and Time 1 anxiety symptoms were uniquely related to higher levels of relational aggression over a 1-year period. Regions of significance were calculated to further decompose significant interactions, which did not differ according to gender. Study findings are discussed within a social information processing theoretical framework, and directions for future research and implications for practice are reviewed. Specifically, co-occurring anxiety symptoms may need to be addressed in interventions for both aggression and peer victimization during middle childhood.


Assuntos
Agressão/psicologia , Ansiedade/psicologia , Bullying , Vítimas de Crime/psicologia , Criança , Feminino , Humanos , Estudos Longitudinais , Masculino , Grupo Associado , Autorrelato
5.
Child Psychiatry Hum Dev ; 48(6): 903-910, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28185109

RESUMO

This study examined associations between reactive and proactive functions of aggression and suicidal behavior in a sample of outpatient treatment seeking youth (n = 111, 60.5% male) ranging from 6 to 17 years of age (Mean age = 10.57 years). Additionally, hope was evaluated as a moderator of these associations. Child reports of measures were used to evaluate associations. When also considering the variance associated with child depressive symptoms and hope, reactive, but not proactive, aggression was uniquely associated with suicidal behavior. Moreover, hope moderated this association, such that reactive aggression was only positively associated with suicidal behavior when levels of hope were low. Findings and their implications for targeting hope with aggressive youth for the prevention of suicidal behavior are discussed.


Assuntos
Agressão/psicologia , Esperança , Ideação Suicida , Tentativa de Suicídio/psicologia , Adolescente , Criança , Depressão/psicologia , Feminino , Humanos , Masculino , Aceitação pelo Paciente de Cuidados de Saúde
6.
Child Psychiatry Hum Dev ; 47(3): 384-96, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26266466

RESUMO

The current study, operating from a stress-process framework, examined the interactive effects of supportive parenting practices (i.e., mothers' use of positive communication, positive parenting, and parental involvement) and maternal psychological control on mother- and child-reported child depressive symptoms in a community-recruited sample of 9-12 year-olds. Discrepancies between reports of depressive symptoms were also examined. Maternal psychological control was uniquely associated with child-, not mother-, reported depressive symptoms. Parental involvement was uniquely associated with mother-, not child-, reported depressive symptoms. Positive parent-child communication was associated with both reports of child depressive symptoms at the bivariate level, but not when unique associations were examined. Positive parenting was unrelated to either report of depressive symptoms. No interaction effects were detected. The current findings highlight the differential importance of parenting practices on child depressive symptoms, and also indicate the necessity of gathering both parent and child reports of symptomatology and family functioning.


Assuntos
Comportamento Infantil , Depressão , Relações Mãe-Filho/psicologia , Mães/psicologia , Apego ao Objeto , Poder Familiar/psicologia , Adulto , Controle Comportamental/psicologia , Criança , Educação Infantil/psicologia , Depressão/diagnóstico , Depressão/psicologia , Depressão/terapia , Diagnóstico Precoce , Relações Familiares/psicologia , Feminino , Humanos , Masculino , Pais/psicologia
7.
J Prim Prev ; 36(6): 405-18, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26500114

RESUMO

There is a dearth of studies concerning the functions of aggression among Latino/a youth despite the fact they are one of the fastest growing youth populations in the United States. We examined individual, peer, cultural, and community level indicators of reactive and proactive aggression and determined whether these relationships were moderated by acculturative dissonance (e.g., culturally specific family conflicts arising from the acculturation process) among a sample of Latino/a adolescents who were predominantly of Mexican heritage. Consistent with prior evidence, results revealed that peer delinquency was uniquely associated with proactive aggression, whereas impulsivity was uniquely associated with reactive aggression. Further, acculturative dissonance was uniquely associated with proactive but not reactive aggression. No moderating effects for acculturative dissonance were found, indicating that the significant risk factors in our study were associated with proactive and reactive aggression regardless of the level of acculturative dissonance experienced. Notably, acculturative dissonance was a unique risk factor for proactive aggression and thus may be an important target for prevention and interventions among Latino/a youth. Consequently, interventions designed to prevent culturally specific family conflicts and promote family functioning may be particularly useful in mitigating the risk of aggression intended to achieve social and material awards among in this population.


Assuntos
Aculturação , Comportamento do Adolescente/psicologia , Agressão/psicologia , Dissonância Cognitiva , Hispânico ou Latino/psicologia , Relações Pais-Filho/etnologia , Características de Residência , Adolescente , Comportamento do Adolescente/etnologia , Depressão/diagnóstico , Depressão/etnologia , Exposição à Violência/etnologia , Exposição à Violência/psicologia , Exposição à Violência/estatística & dados numéricos , Feminino , Humanos , Delinquência Juvenil/etnologia , Delinquência Juvenil/psicologia , Delinquência Juvenil/estatística & dados numéricos , Masculino , Meio-Oeste dos Estados Unidos/epidemiologia , Grupo Associado , Fatores de Risco , Distribuição por Sexo , Valores Sociais/etnologia
8.
Emerg Nurse ; 22(8): 14-5, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25466752

RESUMO

Many junior emergency department nurses are given no formal training in management before they are asked to take charge of shifts. Nurses learn by observing senior staff, but when they first take charge of a busy shift they can be uncertain about what tasks to prioritise and how to manage team members. This article describes some of the techniques they can learn and the observations they should make to run shifts successfully.

9.
Biochim Biophys Acta ; 1822(10): 1516-26, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22613355

RESUMO

Deficiency of UDP-galactose 4'-epimerase is implicated in type III galactosemia. Two variants, p.K161N-hGALE and p.D175N-hGALE, have been previously found in combination with other alleles in patients with a mild form of the disease. Both variants were studied in vivo and in vitro and showed different levels of impairment. p.K161N-hGALE was severely impaired with substantially reduced enzymatic activity, increased thermal stability, reduced cofactor binding and no ability to rescue the galactose-sensitivity of gal10-null yeast. Interestingly p.K161N-hGALE showed less impairment of activity with UDP-N-acetylgalactosamine in comparison to UDP-galactose. Differential scanning fluorimetry revealed that p.K161N-hGALE was more stable than the wild-type protein and only changed stability in the presence of UDP-N-acetylglucosamine and NAD(+). p.D175N-hGALE essentially rescued the galactose-sensitivity of gal10-null yeast, was less stable than the wild-type protein but showed increased stability in the presence of substrates and cofactor. We postulate that p.K161N-hGALE causes its effects by abolishing an important interaction between the protein and the cofactor, whereas p.D175N-hGALE is predicted to remove a stabilizing salt bridge between the ends of two α-helices that contain residues that interact with NAD(+). These results suggest that the cofactor binding is dynamic and that its loss results in significant structural changes that may be important in disease causation.


Assuntos
Coenzimas/metabolismo , Galactosemias/enzimologia , Ligação Proteica/genética , UDPglucose 4-Epimerase/química , UDPglucose 4-Epimerase/genética , UDPglucose 4-Epimerase/metabolismo , Alelos , Coenzimas/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas Fúngicas/metabolismo , Galactose/genética , Galactose/metabolismo , Galactosemias/genética , Humanos , Cinética , Modelos Moleculares , NAD/genética , NAD/metabolismo , Peptídeo Hidrolases/genética , Peptídeo Hidrolases/metabolismo , Desnaturação Proteica , Multimerização Proteica , Estrutura Secundária de Proteína/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Relação Estrutura-Atividade , Uridina Difosfato N-Acetilglicosamina/genética , Uridina Difosfato N-Acetilglicosamina/metabolismo , Leveduras/genética , Leveduras/metabolismo
10.
J Org Chem ; 78(3): 1014-25, 2013 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-23305555

RESUMO

A new series of unsymmetrical diphenylaminofluorene-based chromophores with various strong π-electron acceptors were synthesized and fully characterized. The systematic alteration of the structural design facilitated the investigation of effects such as molecular symmetry and strength of electron-donating and/or -withdrawing termini have on optical nonlinearity. In order to determine the electronic and geometrical properties of the novel compounds, a thorough investigation was carried out by a combination of linear and nonlinear spectroscopic techniques, single-crystal X-ray diffraction, and quantum chemical calculations. Finally, on the basis of two-photon absorption (2PA) cross sections, the general trend for π-electron accepting ability, i.e., ability to accept charge transfer from diphenylamine was: 2-pyran-4-ylidene malononitrile (pyranone) > dicyanovinyl > bis(dicyanomethylidene)indane >1-(thiophen-2-yl)propenone > dicyanoethylenyl >3-(thiophen-2-yl)propenone. An analogue with the 2-pyran-4-ylidene malononitrile acceptor group exhibited a nearly 3-fold enhancement of the 2PA cross section (1650 GM at 840 nm), relative to other members of the series.


Assuntos
Nitrilas/química , Nitrilas/síntese química , Piranos/química , Piranos/síntese química , Absorção , Cristalografia por Raios X , Fótons , Teoria Quântica , Espectrometria de Fluorescência , Difração de Raios X
11.
J Fluoresc ; 2013 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-24078297

RESUMO

The design, synthesis, and photophysical properties of a new fluorene-based fluorescent chemosensor, 4-((E)-2-(2-(benzo[d]thiazol-2-yl)-9,9-diethyl-9H-fluoren-7-yl)vinyl)-N,N-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)benzenamine (AXF-Al), is described for the detection of Al3+. AXF-Al exhibited absorption at 382 nm and strong fluorescence emission at 542 nm (fluorescence quantum yield, Φ F, of 0.80). The capture of Al3+ by the pyrazolyl aniline receptor resulted in nominal change in the linear absorption (372 nm) but a large hypsochromic shift of 161 nm in the fluorescence spectrum (542 to 433 nm, Φ F = 0.88), from which Al3+ was detected both ratiometrically and colorimetrically. The addition of other metal ions, namely Mg2+, Ca2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg 2+ and Pb2+, produced only minimal changes in the optical properties of this probe. The emission band of this probe was also accessed by two-photon excitation in the near-IR, as two-photon absorption (2PA) is important for potential applications in two-photon fluorescence microscopy (2PFM) imaging. The 2PA cross section of the free fluorenyl ligand AXF-Al was 220 GM at 810 nm and 235 GM at 810 nm for the Al-ligand complex, practically useful properties for 2PFM.

12.
Front Psychol ; 14: 1157665, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37057146

RESUMO

Introduction: Observational assessments are important for understanding a range of behaviors and emotions in the young child-caregiver relationship. This paper provides initial data on a multidimensional assessment for professionals who work with young children and their caregivers, the What to Look for in Relationships (WLR). The WLR was designed to assist providers in evaluating strengths and areas for improvement in five areas of young child-caregiver relationship dimensions. This paper reports on the development, interrater reliability, initial convergent and discriminant validity, and incremental utility of the scales. Methods: Data were collected from caregiver-child dyads, who participated in a semi-structured observational caregiver-child interaction session as part of a clinic evaluation for relationship-based therapeutic services for young children in child protection. Recorded interactions were coded using the WLR scales with 146 interactions coded by at least two independent observers for interrater reliability analyses. Results: The scales showed adequate internal consistency, good inter-rater reliability, strong convergent associations with a single dimension measure (i.e., the Parent-Infant Relationship Global Assessment Scale; PIR-GAS) and discriminated those in the clinical range from those with adaptive functioning on the PIR-GAS. Discussion: This study provides initial support for the usefulness of the WLR scales for assessing dimensions of caregiver-child relationships during early childhood that may be useful targets of intervention.

13.
J Phys Chem A ; 116(10): 2453-65, 2012 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-22329623

RESUMO

A novel axially chiral binaphthyl fluorene based salen ligand, AFX-155 [2,2'-(1E,1'E)-(R)-1,1'-binaphthyl-2,2'-diylbis(azan-1-yl-1-ylidene)bis(methan-1-yl-1-ylidene)bis(4-((7-(diphenylamino)-9,9-dihexyl-9H-fluoren-2-l)ethynyl)phenol)], with potential applications in homogeneous catalysis, biophotonics, and sensing was synthesized. A full comparative theoretical-experimental analysis of the UV-vis and electronic circular dichroism (ECD) spectra of the 10 primary isomers, comprising stereoisomers and optical isomers, revealed the presence of the unique structure in tetrahydrofuran (THF) solution, the trans-R-intra//trans-R-extra. A proposed route of attack of the (R)-(+)-2,2'-diamino-1,1'-binapthalene onto a salicaldehyde 5-(2-(2-(diphenylamino)-9,9-dihexyl-9H-fluoren-7-yl)ethynyl)-2-hydroxybenzaldehyde followed by a consecutive attack of the resulting species onto another salicaldehyde, both via Burgi:Dunitz trajectory, validates the unambiguous formation of the established isomer. Steric hindrances seem to be the determinant factor that defines the 3D structural conformation of this particular stereoisomer of AFX-155 with triple axial chirality. The determination of every optimal structure and the dominant conformers of AFX-155 were calculated evaluating, in CONFLEX, their steric energies using force fields at MMFF94S (2006-11-24HGTEMP) level in gas phase. The geometry of the conformers was optimized in THF (using PCM) using Gaussian 09 at the DFT/B3LYP level of theory and 6-31G* basis set. The first 100 electronic excited states were calculated using the same level of theory and basis set.


Assuntos
Etilenodiaminas/química , Fluorenos/química , Naftalenos/química , Teoria Quântica , Dicroísmo Circular , Fluorenos/síntese química , Ligantes , Estrutura Molecular , Soluções
14.
Emerg Nurse ; 20(1): 30-1, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22690476

RESUMO

Every year the RCN Emergency Care Association asks people who want to present at its annual conference to submit abstracts of their work. These requests produce about 100 abstracts of varying quality, which suggests that some nurses are uncertain about how to construct them. This is unfortunate because excellent work can be rejected by reviewers if the associated abstracts are of poor quality. There are few guidelines for people intending to write their first conference abstracts so this article offers some advice on how to do so to maximise the chance of successful application.


Assuntos
Indexação e Redação de Resumos , Pesquisa em Enfermagem , Congressos como Assunto , Enfermagem em Emergência , Humanos , Reino Unido
15.
Am Psychol ; 76(2): 350-363, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33734800

RESUMO

The Adverse Childhood Experiences (ACEs) study (Felitti et al., 1998) has led to an understanding of how exposure to abuse, neglect, and family dysfunction in childhood are related to subsequent physical and mental health problems. These issues are important to consider during the perinatal period, with studies indicating that pregnant women who report adverse experiences in childhood may be at risk of experiencing mental health and substance use problems. This study examined the association of pregnant women's ACEs with symptoms of depression, anxiety, posttraumatic stress, and substance use, and examined the potential buffering effect of women's resilience against the deleterious effects of ACES on mental health and substance use. Women reported on ACES, mental health symptoms, substance use, and resilience when they were screened for participation in a perinatal psychosocial support intervention, which was integrated into obstetrical clinics in a Southern academic medical center. Almost a quarter of the 303 women in this sample reported four or more ACEs, indicating significant risk. Those reporting more overall ACEs also reported more symptoms of depression, posttraumatic stress, and increased risk of tobacco use. Unique effects of specific ACEs subtypes were also found. Women exposed to child maltreatment reported more anxiety, depression, and posttraumatic stress symptoms, and were at risk for tobacco, cannabis, or opioid use during pregnancy. Women exposed to household dysfunction reported more posttraumatic stress symptoms and were at increased risk of tobacco and alcohol use during pregnancy. Women's resilience attenuated effects of household dysfunction on posttraumatic stress symptoms. (PsycInfo Database Record (c) 2021 APA, all rights reserved).


Assuntos
Experiências Adversas da Infância/psicologia , Saúde Mental , Mães/psicologia , Complicações na Gravidez/psicologia , Transtornos Relacionados ao Uso de Substâncias/psicologia , Adolescente , Adulto , Ansiedade , Criança , Maus-Tratos Infantis/psicologia , Depressão , Feminino , Humanos , Pessoa de Meia-Idade , Gravidez , Trauma Psicológico , Resiliência Psicológica , Adulto Jovem
18.
PLoS One ; 12(11): e0184183, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29112947

RESUMO

Carbon-carbon bond formation is one of the most challenging reactions in synthetic organic chemistry, and aldol reactions catalysed by dihydroxyacetone phosphate-dependent aldolases provide a powerful biocatalytic tool for combining C-C bond formation with the generation of two new stereo-centres, with access to all four possible stereoisomers of a compound. Dihydroxyacetone phosphate (DHAP) is unstable so the provision of DHAP for DHAP-dependent aldolases in biocatalytic processes remains complicated. Our research has investigated the efficiency of several different enzymatic cascades for the conversion of glycerol to DHAP, including characterising new candidate enzymes for some of the reaction steps. The most efficient cascade for DHAP production, comprising a one-pot four-enzyme reaction with glycerol kinase, acetate kinase, glycerophosphate oxidase and catalase, was coupled with a DHAP-dependent fructose-1,6-biphosphate aldolase enzyme to demonstrate the production of several rare chiral sugars. The limitation of batch biocatalysis for these reactions and the potential for improvement using kinetic modelling and flow biocatalysis systems is discussed.


Assuntos
Acetato Quinase/metabolismo , Catalase/metabolismo , Fosfato de Di-Hidroxiacetona/metabolismo , Glicerol Quinase/metabolismo , Glicerolfosfato Desidrogenase/metabolismo , Açúcares/síntese química , Biocatálise , Cromatografia Líquida de Alta Pressão , Estereoisomerismo , Açúcares/química
19.
ACS Appl Mater Interfaces ; 7(4): 2833-46, 2015 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-25622309

RESUMO

The synthesis, linear photophysical characterization, and nonlinear optical properties of two new symmetrical fluorene-containing quinolizinium derivatives, 2,8-bis((E)-2-(7-(diphenylamino)-9,9-dihexyl-9H-fluoren-2-yl)vinyl)quinolizinium hexafluorophosphate (1) and 2,8-bis((E)-2-(7-((7-(diphenylamino)-9,9-dihexyl-9H-fluoren-2-yl)ethynyl)-9,9-dihexyl-9H-fluoren-2yl)vinyl)quinolizinium hexafluorophosphate (2), are reported. The nature of the dual-band steady-state fluorescence emission of 1 and 2 was determined, and violation of Kasha's rule along with a strong dependence on solvent polarity were shown. A relatively complex structure of two-photon absorption (2PA) spectra of 1 and 2, with maximum cross sections of ∼400-600 GM, was determined using the open aperture Z-scan method. Different types of fast relaxation processes with characteristic times of 0.3-0.5 ps and 1.5-2 ps were observed in the excited states of the new compounds via femtosecond transient absorption pump-probe spectroscopy. To better understand the photophysical behavior of 1 and 2, a quantum-mechanical study was undertaken using TD-DFT and ZINDO/S methods. Simulated linear absorption spectra were found to be in good agreement with experimental data, while 2PA cross sections were overestimated. Although the new dyes were highly fluorescent in nonpolar solvents, they were essentially nonfluorescent in polar media. Significantly, the quinolizinium dyes exhibited fluorescence turn-on behavior upon binding to bovine serum album (BSA) protein, exhibiting over 4-fold fluorescence enhancement, which was a finding that was leveraged to demonstrate cell membrane fluorescence imaging of HeLa cells.


Assuntos
Membrana Celular/química , Fluorenos/química , Corantes Fluorescentes/química , Quinolizinas/química , Cátions/química , Células/química , Fluorescência , Corantes Fluorescentes/síntese química , Células HeLa , Humanos , Espectrometria de Fluorescência
20.
J Psychopathol Behav Assess ; 36(4): 653-662, 2014 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-25364098

RESUMO

Ample research suggests that delinquency, depressive symptoms, and peer substance use are common risk factors associated with adolescent substance use. However, the factors that may help to buffer the deleterious effects of these risk factors on adolescent substance use, such as hope, have yet to be examined. The current study evaluated hope as a moderator of the associations between these common risk factors and frequency of substance use (alcohol, tobacco, and marijuana) in a sample of Latino high school students (Mage = 16.14years, SD = 1.30; 55% female). Findings indicated that the influence of delinquency on frequency of tobacco and marijuana use depended on levels of hope, with delinquency only positively associated with frequency of use when levels of hope were low. Additionally, hope moderated the association between depressive symptoms and alcohol use, such that depressive symptoms were only positively associated with frequency of alcohol use when levels of hope were low. Results and their implications for intervention are reviewed.

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