Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 170
Filtrar
Mais filtros

Bases de dados
Tipo de documento
Intervalo de ano de publicação
1.
New Phytol ; 243(5): 1887-1898, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38984686

RESUMO

The role of maternal tissue in embryogenesis remains enigmatic in many complex organisms. Here, we investigate the contribution of maternal tissue to apical-basal patterning in the kelp embryo. Focussing on Undaria pinnatifida, we studied the effects of detachment from the maternal tissue using microsurgery, staining of cell wall modifications, morphometric measurements, flow cytometry, genotyping and a modified kelp fertilisation protocol synchronising kelp embryogenesis. Detached embryos are rounder and often show aberrant morphologies. When a part of the oogonial cell wall remains attached to the zygote, the apical-basal patterning is rescued. Furthermore, the absence of contact with maternal tissue increases parthenogenesis, highlighting the critical role of maternal signals in the initial stages of development. These results show a key role for the connection to the maternal oogonial cell wall in apical-basal patterning in kelps. This observation is reminiscent of another brown alga, Fucus, where the cell wall directs the cell fate. Our findings suggest a conserved mechanism across phylogenetically distant oogamous lineages, where localised secretion of sulphated F2 fucans mediates the establishment of the apical-basal polarity. In this model, the maternal oogonial cell wall mediates basal cell fate determination by providing an extrinsic patterning cue to the future kelp embryo.


Assuntos
Parede Celular , Undaria , Undaria/fisiologia , Parede Celular/metabolismo , Padronização Corporal , Kelp/fisiologia , Partenogênese , Algas Comestíveis
2.
Contact Dermatitis ; 90(2): 116-125, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37735996

RESUMO

BACKGROUND: Rubber accelerators are used in the production of rubber gloves and may cause contact allergy. OBJECTIVES: To estimate long-term trend and prevalence of contact allergy to rubber accelerators for a 30-year period in Denmark, high-risk occupations, and exposures. METHODS: Data from all patients with contact dermatitis consecutively patch tested at the department of Skin and Allergy Gentofte hospital with the rubber accelerators from the European baseline series (EBS) from 1990 to 2019, were analysed. Further, patients under suspicion of rubber accelerator contact allergy were additionally patch-tested with rubber accelerators from the specialised rubber series from 2005 to 2019 and these were additional extracted. RESULTS: The overall prevalence of contact allergy to one or more of the rubber accelerators from the EBS series was 2.7% with a significant decline in the first 12-years, followed by a stable frequency in the past 18-years. Associations with occupational contact dermatitis, hand dermatitis, and leg/foot dermatitis were found. Wet-work occupations were most often affected and gloves the most frequent exposure. CONCLUSIONS: Contact allergy to one or more of the rubber accelerators from the EBS is frequent and has been unchanged for several decades, which calls for prevention.


Assuntos
Dermatite Alérgica de Contato , Dermatite Ocupacional , Eczema , Hipersensibilidade ao Látex , Humanos , Dermatite Alérgica de Contato/diagnóstico , Dermatite Alérgica de Contato/epidemiologia , Dermatite Alérgica de Contato/etiologia , Borracha/efeitos adversos , Testes do Emplastro/efeitos adversos , Dermatite Ocupacional/etiologia , Dermatite Ocupacional/complicações , Hipersensibilidade ao Látex/epidemiologia , Eczema/epidemiologia , Eczema/complicações , Dinamarca/epidemiologia
3.
Contact Dermatitis ; 91(5): 392-397, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-39041641

RESUMO

BACKGROUND: Neomycin is an aminoglycoside antibiotic that may cause contact allergy. It was withdrawn as a medicine for human use in Denmark in October 2009 but is still found in some vaccines. OBJECTIVES: To identify time trends in contact allergy to neomycin in the period from 2000 to 2023. METHODS: A cross-section study of patients ≥18 years consecutively patch-tested with neomycin sulfate (20% in pet.) at Gentofte Hospital, Denmark, during the period 2000-2023 was conducted. RESULTS: The overall prevalence of contact allergy to neomycin was 1.4%. The prevalence was significantly lower in the period '2010-2023' (1.2%) than in '2000-2009' (1.8%) (p < 0.005). Contact allergy to neomycin was significantly positively associated with facial dermatitis and age >40 years, and significantly negatively associated with occupational dermatitis and hand dermatitis. No changes in sex, occupational dermatitis, atopic dermatitis, hand dermatitis, leg dermatitis, facial dermatitis, or age > 40/≤40 (the MOAHLFA-index) were identified when comparing neomycin contact allergic-patients in the two periods '2010-2023' and '2001-2009'. CONCLUSION: Neomycin is a rare cause of contact allergy in Denmark with a significantly lower prevalence following its withdrawal as a medicinal product for human use in Denmark in 2009.


Assuntos
Dermatite Alérgica de Contato , Neomicina , Testes do Emplastro , Humanos , Dinamarca/epidemiologia , Neomicina/efeitos adversos , Dermatite Alérgica de Contato/etiologia , Dermatite Alérgica de Contato/epidemiologia , Estudos Transversais , Feminino , Masculino , Adulto , Prevalência , Pessoa de Meia-Idade , Antibacterianos/efeitos adversos , Dermatite Ocupacional/epidemiologia , Dermatite Ocupacional/etiologia , Dermatoses Faciais/epidemiologia , Dermatoses Faciais/induzido quimicamente , Dermatoses da Mão/epidemiologia , Dermatoses da Mão/induzido quimicamente , Adulto Jovem , Idoso , Eczema/epidemiologia , Eczema/induzido quimicamente , Fatores Etários , Dermatoses da Perna/induzido quimicamente , Dermatoses da Perna/epidemiologia , Adolescente
4.
Contact Dermatitis ; 2024 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-39367740

RESUMO

BACKGROUND: Rubber gloves contain rubber accelerators that may cause contact allergy. The content of sensitising rubber accelerators in contemporary rubber gloves is not well known. OBJECTIVES: Identify and quantify the content of rubber accelerators in disposable rubber gloves. METHODS: Fifty-one gloves of 49 different brands were collected. Forty-eight of the gloves were disposable and three re-usable. The gloves were analysed for their content of sensitising rubber accelerators, that is, zinc dithiocarbamates, thiurams, thiazoles/benzothiazoles, diphenylguanidine, and thioureas by high-performance liquid chromatography. RESULTS: Rubber accelerators were identified in 43/48 (90%) of the disposable gloves. In total, 39 gloves contained zinc dibutyldithiocarbamate (ZDBC) (0.18-1.96 mg/g), 34 zinc diethyldithiocarbamate (ZDEC) (0.032-2.78 mg/g), three zinc dibenzyldithiocarbamate (0.65-1.4 mg/g), one zinc dimethyldithiocarbamate (0.23 mg/g), and one 1,3-diphenylguanidine (0.21 mg/g). 2-cyanoethyl dimethyldithiocarbamate (CEDMC) was identified in three gloves (<0.052 mg/g). The one glove labelled as accelerator free contained ZDBC (1.07 mg/g). Only few glove packages had the specific content of rubber accelerators labelled. CONCLUSIONS: The most frequent rubber accelerators in rubber gloves are ZDEC and ZDBC. Accelerator-free gloves may contain rubber accelerators. Full labelling of rubber gloves is needed and producers should be sure not to falsely claim that the rubber gloves are free of rubber accelerators.

5.
Contact Dermatitis ; 2024 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-39340203

RESUMO

BACKGROUND: Rubber accelerators are used in the vulcanization of rubber. However, rubber accelerators for example tetraethylthiuram disulfide (TETD) and zinc diethyldithiocarbamate (ZDEC) may cause contact allergy. Concomitant reactions between ZDEC and TETD have been observed in patients which could be explained by co- or cross-reactivity. OBJECTIVES: To investigate cross-reactivity between TETD and ZDEC and vice versa. METHODS: Groups of mice were sensitized with TETD or ZDEC based on reported EC3-values. Proliferation of lymphocytes were measured on day 5. To test cross-reactivity, mice were sensitized and challenged 3 weeks later with TETD or ZDEC. The inflammatory response was measured by changes in ear thickness and the proliferative response in CD4+ and CD8+ T cells in the submandibular and cervical draining lymph nodes. RESULTS: Sensitization of mice with doses of ZDEC 3%, TETD 5.6% or TETD 16.2% induced significant increased ear thickness and proliferation of CD4+ and CD8+ T cells. Challenge with ZDEC or TETD in these groups induced significant increased ear thickness. Challenge with ZDEC in mice sensitized to TETD 5.6% or TETD 16.2% induced significant increased proliferation of CD4+ and CD8+ T cells. CONCLUSIONS: We show cross-reactivity between TETD and ZDEC. Patients sensitized to TETD or ZDEC should avoid exposure to both ZDEC and TETD.

6.
Contact Dermatitis ; 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-39021255

RESUMO

BACKGROUND: The use of methylisothiazolinone (MI) as a preservative in cosmetic products caused an alarming increase in MI contact allergy across Europe in the 2010s. This was followed by regulations of use with a total ban on leave-on (implemented in 2017) and reduced use concentrations in rinse-off cosmetics (2018). OBJECTIVE: To follow-up on the prevalence of contact allergy to MI and the related benzisothiazolinone (BIT) and octylisothiazolinone (OIT) in consecutively patch-tested patients in Europe. METHODS: A cross-sectional audit following the design of two previous audits on MI contact allergy from 1 May 2022 to 31 October 2022 included all patients patch tested with the European baseline series, including or supplemented with MI, BIT and OIT across 10 departments in eight European countries. RESULTS: A total of 2554 patients were consecutively patch tested with the three isothiazolinones during the study period. The prevalence of MI and BIT contact allergy was 2.9% (95% confidence interval [CI]: 2.3%-3.7%; range 1.1%-5.8%) and 3.1% (95% CI: 2.4%-3.9%; range 0.0%-6.6%), respectively; that of OIT was 0.7% (95% CI: 0.4%-1.1%; range 0%-3.2%). Rinse-off cosmetic (73.3%) and leave-on cosmetic products (13.3%) were still associated with eliciting allergic contact dermatitis to MI. CONCLUSION: We confirmed a positive impact of regulatory measures on the prevalence of MI contact allergy in Europe, which halved compared to 2015. However, our data suggest that consumers may still be exposed to older cosmetic products containing MI. BIT has superseded MI in causing contact allergy, despite not being allowed for use in cosmetic products.

7.
Br J Anaesth ; 131(4): 644-648, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37718095

RESUMO

The first modern intensive care unit was established in Copenhagen 70 yr ago. This cornerstone of anaesthesia was largely based on experience gained using positive pressure ventilation to save hundreds of patients during the polio epidemic in 1952. Ventilation approaches, monitoring techniques, and pharmacological innovations have developed to such an extent that cuirass ventilation, which proved inadequate during the polio epidemic, might now have novel applications for both anaesthesia and treatment of the critically ill.


Assuntos
Aniversários e Eventos Especiais , Poliomielite , Humanos , Respiração , Respiração com Pressão Positiva , Unidades de Terapia Intensiva
8.
Osteoarthritis Cartilage ; 30(8): 1116-1129, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35569800

RESUMO

OBJECTIVE: Hip osteoarthritis (OA) affects all components of the osteochondral unit, leading to bone marrow (BM) lesions, and unknown consequences on BM cell functionality. We analyzed the cellular composition in OA-affected acetabula compared to proximal femur shafts obtained of hip OA patients to reveal yet not explored immune and stem cell compartments. DESIGN: Combining flow cytometry, cellular assays and transcription analyses, we performed extensive ex vivo phenotyping of acetabular BM cells from 18 hip OA patients, comparing them with their counterparts from patient-matched femoral shaft BM samples. Findings were related to differences in skeletal sites and age. RESULTS: Acetabular BM had a greater frequency of T-lymphocytes, non-hematopoietic cells and colony-forming units fibroblastic potential than femoral BM. The incidence of acetabular CD45+CD3+ T-lymphocytes increased (95% CI: 0.1770 to 0.0.8416), while clonogenic hematopoietic progenitors declined (95% CI: -0.9023 to -0.2399) with age of patients. On the other side, in femoral BM, we observed higher B-lymphocyte, myeloid and erythroid cell frequencies. Acetabular mesenchymal stromal cells (MSCs) showed a senescent profile associated with the expression of survival and inflammation-related genes. Efficient osteogenic and chondrogenic differentiation was detected in acetabular MSCs, while adipogenesis was more pronounced in their femoral counterparts. CONCLUSION: Our results suggest that distinctions in BM cellular compartments and MSCs may be due to the influence of the OA-stressed microenvironment, but also acetabular vs femoral shaft-specific peculiarities cannot be excluded. These results bring new knowledge on acetabular BM cell populations and may be addressed as novel pathogenic mechanisms and therapeutic targets in OA.


Assuntos
Doenças das Cartilagens , Osteoartrite do Quadril , Acetábulo , Medula Óssea , Células da Medula Óssea , Doenças das Cartilagens/metabolismo , Diferenciação Celular , Humanos , Osteoartrite do Quadril/metabolismo , Células-Tronco
9.
Osteoporos Int ; 33(8): 1643-1657, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35304613

RESUMO

PURPOSE: The primary objective of the present systematic review and meta-analysis was to determine the effect of differing exercise intensity on (areal) bone mineral density (BMD) at lumbar spine and hip in adults by a comparative meta-analysis. METHODS: A systematic review of the literature according to the PRISMA statement included: (a) exercise trials, (b) with ≥two study arms that compared different exercise intensities, (c) intervention ≥6 months, (d) BMD assessments at lumbar spine (LS) or hip. Five electronic databases were scanned without language restrictions up to July 2021. The present analysis of exercise intensity was conducted as a mixed-effect meta-analysis and applied "type of exercise" and "study duration" as moderator in subgroup analyses. Outcome measures were standardized mean differences (SMD) for BMD changes at the LS, and hip. RESULTS: Eleven exercise studies with 26 study arms were included. Although the effect of high-intensity exercise was more pronounced on LS-BMD (SMD: 0.19, 95%-CI: 0.61 to -0.23) and hip-ROI (0.17, 0.38 to -0.04), we did not observe significant differences between the groups (LS-BMD: p=0.373 and hip-BMD: p=0.109). We observed a substantial level of heterogeneity between the trials for LS- but not for hip-BMD. Applying "type of exercise" and "study duration" as moderators did not significantly modify the differences between low and high exercise intensity on BMD at LS or hip. CONCLUSION: There is insufficient evidence for a superior effect of high-intensity exercise on areal BMD at lumbar spine and hip in people aged 50 years and older. Varying exercise intensity with periods of lower exercise intensity intermitted by higher intensity might be a promising option to address the issue of exercise intensities in intervention studies.


Assuntos
Densidade Óssea , Vértebras Lombares , Adulto , Idoso , Exercício Físico , Humanos , Pessoa de Meia-Idade
10.
Diabet Med ; 39(1): e14704, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34596251

RESUMO

AIM: To estimate the prevalence of sexual dysfunction in women with type 1 diabetes (T1D) compared with women without diabetes and to analyse associations between sexual dysfunction and the presence of chronic physical diabetes complications, diabetes distress and depression in women with T1D. METHODS: This cross-sectional study was conducted in Norway, and 171 women with T1D and 60 controls completed the Female Sexual Function Index (FSFI) and the Hospital Anxiety and Depression Scale (HADS). Diabetes distress was assessed with the Problem Areas in Diabetes (PAID) scale. Data on diabetes complications were retrieved from medical records. We performed logistic regression to estimate differences in the prevalence of sexual dysfunction (defined as FSFI ≤26.55) between women with T1D and women without diabetes and to examine associations of sexual dysfunction with chronic diabetes complications, diabetes distress and depression in women with T1D. RESULTS: The prevalence of sexual dysfunction was higher in women with T1D (50.3%) compared with the controls (35.0%; unadjusted odds ratio [OR] 1.89 [95% confidence interval (CI) 1.06-3.37]; adjusted OR 1.93 [1.05-3.56]). In women with T1D, sexual dysfunction was associated with both diabetes distress (adjusted OR 1.03 [1.01-1.05]) and depression (adjusted OR 1.28 [1.12-1.46]), but there were no clear associations with chronic diabetes complications (adjusted OR 1.46 [0.67-3.19]). CONCLUSIONS: This study suggests that sexual dysfunction is more prevalent in women with T1D compared with women without diabetes. The study findings emphasize the importance of including sexual health in relation to diabetes distress and psychological aspects in diabetes care and future research.


Assuntos
Diabetes Mellitus Tipo 1/complicações , Qualidade de Vida , Disfunções Sexuais Fisiológicas/etiologia , Disfunções Sexuais Psicogênicas/etiologia , Adolescente , Adulto , Idoso , Estudos Transversais , Diabetes Mellitus Tipo 1/psicologia , Feminino , Humanos , Incidência , Pessoa de Meia-Idade , Noruega/epidemiologia , Prevalência , Disfunções Sexuais Fisiológicas/epidemiologia , Disfunções Sexuais Psicogênicas/epidemiologia , Inquéritos e Questionários , Adulto Jovem
11.
Osteoporos Int ; 31(8): 1445-1460, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32162014

RESUMO

This article provides an overview of the current knowledge on hypophosphatasia-a rare genetic disease of very variable presentation and severity-with a special focus on adolescents and adults. It summarizes the available information on the many known mutations of tissue-nonspecific alkaline phosphatase (TNSALP), the epidemiology and clinical presentation of the disease in adolescents and adults, and the essential diagnostic clues. The last section reviews the therapeutic approaches, including recent reports on enzyme replacement therapy (EnzRT).


Assuntos
Hipofosfatasia , Adolescente , Adulto , Fosfatase Alcalina/uso terapêutico , Terapia de Reposição de Enzimas , Humanos , Hipofosfatasia/diagnóstico , Hipofosfatasia/epidemiologia , Hipofosfatasia/terapia , Mutação
12.
Brain ; 142(4): 978-991, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30860258

RESUMO

Stroke is a leading cause of cognitive impairment and dementia, but the mechanisms that underlie post-stroke cognitive decline are not well understood. Stroke produces profound local and systemic immune responses that engage all major innate and adaptive immune compartments. However, whether the systemic immune response to stroke contributes to long-term disability remains ill-defined. We used a single-cell mass cytometry approach to comprehensively and functionally characterize the systemic immune response to stroke in longitudinal blood samples from 24 patients over the course of 1 year and correlated the immune response with changes in cognitive functioning between 90 and 365 days post-stroke. Using elastic net regularized regression modelling, we identified key elements of a robust and prolonged systemic immune response to ischaemic stroke that occurs in three phases: an acute phase (Day 2) characterized by increased signal transducer and activator of transcription 3 (STAT3) signalling responses in innate immune cell types, an intermediate phase (Day 5) characterized by increased cAMP response element-binding protein (CREB) signalling responses in adaptive immune cell types, and a late phase (Day 90) by persistent elevation of neutrophils, and immunoglobulin M+ (IgM+) B cells. By Day 365 there was no detectable difference between these samples and those from an age- and gender-matched patient cohort without stroke. When regressed against the change in the Montreal Cognitive Assessment scores between Days 90 and 365 after stroke, the acute inflammatory phase Elastic Net model correlated with post-stroke cognitive trajectories (r = -0.692, Bonferroni-corrected P = 0.039). The results demonstrate the utility of a deep immune profiling approach with mass cytometry for the identification of clinically relevant immune correlates of long-term cognitive trajectories.


Assuntos
Cognição/fisiologia , Acidente Vascular Cerebral/imunologia , Acidente Vascular Cerebral/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Isquemia Encefálica/complicações , Proteína de Ligação a CREB/metabolismo , Transtornos Cognitivos/etiologia , Transtornos Cognitivos/imunologia , Disfunção Cognitiva/complicações , Disfunção Cognitiva/imunologia , Estudos de Coortes , Feminino , Humanos , Imunoglobulina M , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Neutrófilos , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais , Acidente Vascular Cerebral/complicações , Sobreviventes
15.
Chemistry ; 24(59): 15818-15824, 2018 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-30151869

RESUMO

A systematic series of superbenzene-porphyrin conjugates was synthesized and characterized. All conjugates show a high degree of cluster formation that correlates to the amount of tert-butylated hexa-peri-hexabenzocoronenes (tBuHBCs) attached to the porphyrin's periphery. Determined by mass spectrometry and X-ray diffraction, van der Waals (vdW) interactions like London dispersions (LD), stemming from solubilizing tert-butyl groups, were identified to be the major reason for the cluster formation. Cluster sizes comprised of more than twenty molecules with masses up to 70 000 Da were observed, which are rare examples of large architectures based on synthetic functional molecules, assembled by dispersion interactions. Novel strategies towards the design of solution processable functional materials, capable of dynamic transformations based on non-covalent synthesis can be envisioned.

16.
Geophys Res Lett ; 45(19): 10464-10473, 2018 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31031450

RESUMO

Glaciers in High Mountain Asia, many of which exhibit surface debris, contain the largest volume of ice outside of the polar regions. Many contain supraglacial pond networks that enhance melt rates locally, but no large-scale assessment of their impact on melt rates exists. Here we use surface energy balance modeling forced using locally measured meteorological data and monthly satellite-derived pond distributions to estimate the total melt enhancement for the four main glaciers within the 400-km2 Langtang catchment, Nepal, for a 6-month period in 2014. Ponds account for 0.20 ± 0.03 m/year of surface melt, representing a local melt enhancement of a factor of 14 ± 3 compared with the debris-covered area, and equivalent to 12.5 ± 2.0% of total catchment ice loss. Given the prevalence of supraglacial ponds across the region, our results suggest that effective incorporation of melt enhancement by ponds is essential for accurate predictions of future mass balance change in the region.

18.
Contact Dermatitis ; 78(4): 246-253, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29265415

RESUMO

BACKGROUND: An increasing incidence of contact allergy to methylisothiazolinone (MI) has been seen, caused, in particular, by cosmetic products and paints. A study from 2015 showed that 93.0% of paints bought in five European countries contained MI. New regulations have been discussed for paints in the EU, which may have influenced this market. OBJECTIVES: To re-evaluate the use and concentrations of MI and four other isothiazolinones in water-based wall paints. METHODS: Water-based white wall paints (n = 60) were purchased in retail stores in five European countries: Denmark, France, Germany, Sweden, and the United Kingdom. The paints were analysed for isothiazolione content by the use of high-performance liquid chromatography coupled to ultraviolet detection, and the results were confirmed with high-performance liquid chromatography-tandem mass spectrometry. RESULTS: MI was identified in 55 (91.7%) of the paints, with concentrations ranging from 1.1 to 142.7 ppm. The other isothiazolinones were identified in 20.0% [methylchloroisothiazolinone (MCI)] to 88.3% [benzisothiazolinone (BIT)] of the paints. BIT concentrations varied significantly between countries, whereas MI and MCI concentrations did not. There were no statistically significant differences in MI, MCI and BIT concentrations between the current study and the 2015 study. CONCLUSIONS: MI and other isothiazolinones are widely used in paints available in Europe. Their use does not seem to be decreasing.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Dermatite Alérgica de Contato/prevenção & controle , Pintura/análise , Tiazóis/análise , Dinamarca , Dermatite Alérgica de Contato/etiologia , França , Alemanha , Humanos , Incidência , Teste de Materiais , Exposição Ocupacional/efeitos adversos , Pintura/efeitos adversos , Medição de Risco , Estatísticas não Paramétricas , Tiazóis/química , Reino Unido
19.
J Am Chem Soc ; 139(34): 11760-11765, 2017 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-28762268

RESUMO

Graphene-porphyrin nanohybrid materials with a direct covalent linkage between the graphene carbon network and the functional porphyrin unit have been successfully synthesized via a one-pot reductive diazotation approach. A graphite-potassium intercalation compound (KC8) was dispersed in THF, and different isolated porphyrin-diazonium salts were added. The direct covalent binding and the detailed characterization of the functional hybrid material were carried out by Raman spectroscopy, TG-MS, UV/vis, and fluorescence spectroscopy. LDI-ToF mass spectrometry was introduced as a new versatile and sensitive tool to investigate covalently functionalized graphene derivatives and to establish the composition of the respective nanohybrid materials.

20.
Chemistry ; 23(50): 12353-12362, 2017 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-28574611

RESUMO

We describe the synthesis as well as the electronic and photophysical characterization of novel N-heterotriangulene derivatives decorated with methoxycarbonyl- and methyl-sulfanyl-substituted dithiafulvenyl moieties. The association of these electron-rich compounds with fullerene C60 as electron acceptor was investigated by means of photophysical, voltammetric, and mass spectrometric methods and rationalized by DFT calculations. Importantly, light-induced interactions between the dithiafulvene-substituted N-heterotriangulene bearing methoxycarbonyl substituents with C60 leads to cooperative fluorescence. Quantitative Job plot analyses by means of fluorescence spectroscopy and voltammetry confirm a 1:1 association with binding constants in the order of 104 m-1 . Supportive results for the supramolecular assembly of both N-heterotriangulenes with C60 were obtained by ESI mass spectrometric investigations in the gas phase.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA