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1.
Int J Cardiol Heart Vasc ; 42: 101109, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36110246

RESUMO

Background: A novel catheter technology (direct sense, DS) enables periprocedural local impedance (LI) measurement for estimation of tissue contact during radiofrequency ablation (RFA) for real-time assessment of lesion generation. This measure reflects specific local myocardial conduction properties in contrast to the established global impedance (GI) using a neutral body electrode. Our study aimed to assess representative LI values for the cardiac chambers, to evaluate LI drop in response to RF delivery and to compare those values to established GI measures in patients undergoing RFA procedures. Methods and Results: Seventy-three patients undergoing RFA with the DS technology were included. Within the cardiac chambers, baseline LI was significantly different, with the highest values in the left atrium (LA 107.5 ± 14.3 Ω; RV 104.6 Ω ± 12.9 Ω; LV 100.7 Ω ± 11.7 Ω, and RA 100.5 Ω ± 13.4 Ω). Baseline LI was positively correlated to the corresponding LI drop during RF delivery (R2 = 0.26, p = 0.01) representing a promising surrogate of lesion generation. The observed mean LI drop (15.6 ± 9.5 Ω) was threefold higher as GI drop (4.9 ± 7.4 Ω), p < 0.01. We evaluated the clinical outcome in a subgroup of patients undergoing DS-guided pulmonary vein isolation, which was comparable regarding arrhythmia recurrence to a conventional ablation cohort (57 % vs 50 %, p = 0.2). Conclusion: We provide detailed information on LI measures in electrophysiological procedures with significant differences within the cardiac chambers highlighting that RFA-related LI drop can serve as a promising surrogate for real-time assessment of lesion generation. Guiding the electrophysiologist in RFA procedures, this additional information promises to improve safety profile and success rates in the interventional treatment of arrhythmias.

2.
J Phys Chem A ; 126(8): 1393-1402, 2022 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-35192353

RESUMO

One strategy to improve the photovoltaic properties of nonfullerene acceptors (NFAs), employed in state-of-art organic solar cells, is the rational fluorination or chlorination of these molecules. Although this modification improves important acceptor properties, little is known about the effects on the triplet states. Here, we combine the polarizable continuum model with an optimally tuned range-separated hybrid functional to investigate this issue. We find that fluorination or chlorination of NFAs decreases the degree of the highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) overlap along these molecules. Consequently, the energy gap between T1 and S1 states, ΔEST = ES1 - ET1, also decreases. This effect reduces the binding energy of triplet excitons, which favors their dissociation into free charges. Furthermore, the reduction of ΔEST can contribute to mitigating the losses produced by the nonradiative deactivation of the T1 excitons. Interestingly, although Cl has a lower electronegativity than F, chlorination is more effective to reduce ΔEST. Since the chlorination of NFAs is easier than fluorination, Cl substitution can be a useful approach to enhance solar energy harvesting using triplet excitons.

3.
Ann Oncol ; 32(4): 488-499, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33385521

RESUMO

BACKGROUND: Palbociclib plus endocrine therapy (ET) is the standard treatment of hormone receptor-positive and human epidermal growth factor receptor 2-negative, metastatic breast cancer (MBC). However, its efficacy has not been compared with that of chemotherapy in a phase III trial. PATIENTS AND METHODS: PEARL is a multicentre, phase III randomised study in which patients with aromatase inhibitor (AI)-resistant MBC were included in two consecutive cohorts. In cohort 1, patients were randomised 1 : 1 to palbociclib plus exemestane or capecitabine. On discovering new evidence about estrogen receptor-1 (ESR1) mutations inducing resistance to AIs, the trial was amended to include cohort 2, in which patients were randomised 1 : 1 between palbociclib plus fulvestrant and capecitabine. The stratification criteria were disease site, prior sensitivity to ET, prior chemotherapy for MBC, and country of origin. Co-primary endpoints were progression-free survival (PFS) in cohort 2 and in wild-type ESR1 patients (cohort 1 + cohort 2). ESR1 hotspot mutations were analysed in baseline circulating tumour DNA. RESULTS: From March 2014 to July 2018, 296 and 305 patients were included in cohort 1 and cohort 2, respectively. Palbociclib plus ET was not superior to capecitabine in both cohort 2 [median PFS: 7.5 versus 10.0 months; adjusted hazard ratio (aHR): 1.13; 95% confidence interval (CI): 0.85-1.50] and wild-type ESR1 patients (median PFS: 8.0 versus 10.6 months; aHR: 1.11; 95% CI: 0.87-1.41). The most frequent grade 3-4 toxicities with palbociclib plus exemestane, palbociclib plus fulvestrant and capecitabine, respectively, were neutropenia (57.4%, 55.7% and 5.5%), hand/foot syndrome (0%, 0% and 23.5%), and diarrhoea (1.3%, 1.3% and 7.6%). Palbociclib plus ET offered better quality of life (aHR for time to deterioration of global health status: 0.67; 95% CI: 0.53-0.85). CONCLUSIONS: There was no statistical superiority of palbociclib plus ET over capecitabine with respect to PFS in MBC patients resistant to AIs. Palbociclib plus ET showed a better safety profile and improved quality of life.


Assuntos
Inibidores da Aromatase , Neoplasias da Mama , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Inibidores da Aromatase/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Capecitabina/uso terapêutico , Família de Proteínas EGF/uso terapêutico , Humanos , Piperazinas , Piridinas , Qualidade de Vida , Receptor ErbB-2/genética , Receptores de Estrogênio
4.
Respir Med ; 170: 105939, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32843157

RESUMO

The present 2019 S2k consensus guideline of the German Respiratory Society was written for pneumologists - in contrast to the more general predecessor's S3 guidelines from 2004 to 2010 -, since 2014 the German College of General Practitioners and Family Physicians (DEGAM) published their own cough guidelines. The guidelines contain 48 recommendations agreed upon the consensus and 16 statements, which are explained in the background text in the following nine chapters: epidemiology, physiology, classification, acute, subacute or chronic cough, diagnostics and therapy; an extra chapter was dedicated to chronic idiopathic/refractory cough. Further emphasis of the guidelines is the physiology of cough in anticipation of the introduction of new drugs, as well as detailed treatment for cough triggered by affectations of the upper respiratory tract or gastroesophageal reflux. The guideline should provide the pneumologist with the latest knowledge for neighboring disciplines required for diagnosis and therapy of cough. The clinical chapters also contain a short summary, practical recommendations and a bibliography of their own. Three new simplified algorithms for acute, subacute and chronic cough, round off the diagnostics chapter.


Assuntos
Tosse/diagnóstico , Tosse/terapia , Guias de Prática Clínica como Assunto , Pneumologia/organização & administração , Sociedades Médicas/organização & administração , Doença Aguda , Adulto , Algoritmos , Doença Crônica , Tosse/epidemiologia , Tosse/etiologia , Feminino , Alemanha , Humanos , Masculino , Fatores de Tempo
5.
Ann Oncol ; 30(9): 1514-1520, 2019 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-31250880

RESUMO

BACKGROUND: The CDK4/6 inhibitor palbociclib prolongs progression-free survival in hormone receptor-positive/HER2-negative (HR+/HER2-) metastatic breast cancer when combined with endocrine therapy. This phase II trial was designed to determine the feasibility of adjuvant palbociclib and endocrine therapy for early breast cancer. PATIENTS AND METHODS: Eligible patients with HR+/HER2- stage II-III breast cancer received 2 years of palbociclib at 125 mg daily, 3 weeks on/1 week off, with endocrine therapy. The primary end point was discontinuation from palbociclib due to toxicity, non-adherence, or events related to tolerability. A discontinuation rate of 48% or higher would indicate the treatment duration of 2 years was not feasible, and was evaluated under a binomial test using a one-sided α = 0.025. RESULTS: Overall, 162 patients initiated palbociclib; over half had stage III disease (52%) and most received prior chemotherapy (80%). A total of 102 patients (63%) completed 2 years of palbociclib; 50 patients discontinued early for protocol-related reasons (31%, 95% CI 24% to 39%, P = 0.001), and 10 discontinued due to protocol-unrelated reasons. The cumulative incidence of protocol-related discontinuation was 21% (95% CI 14% to 27%) at 12 months from start of treatment. Rates of palbociclib-related toxicity were congruent with the metastatic experience, and there were no cases of febrile neutropenia. Ninety-one patients (56%) required at least one dose reduction. CONCLUSION: Adjuvant palbociclib is feasible in early breast cancer, with a high proportion of patients able to complete 2 years of therapy. The safety profile in the adjuvant setting mirrors that observed in metastatic disease, with approximately half of the patients requiring dose-modification. As extended duration adjuvant palbociclib appears feasible and tolerable for most patients, randomized phase III trials are evaluating clinical benefit in this population. CLINICALTRIALS.GOV REGISTRATION: NCT02040857.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Neoplasias da Mama/tratamento farmacológico , Piperazinas/administração & dosagem , Inibidores de Proteínas Quinases/administração & dosagem , Piridinas/administração & dosagem , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Quimioterapia Adjuvante/efeitos adversos , Intervalo Livre de Doença , Estradiol/genética , Estudos de Viabilidade , Feminino , Fulvestranto/administração & dosagem , Humanos , Pessoa de Meia-Idade , Invasividade Neoplásica/genética , Invasividade Neoplásica/patologia , Estadiamento de Neoplasias , Piperazinas/efeitos adversos , Inibidores de Proteínas Quinases/efeitos adversos , Piridinas/efeitos adversos , Receptor ErbB-2/genética , Receptores de Estrogênio/genética , Receptores de Progesterona/genética
6.
Sci Rep ; 9(1): 8830, 2019 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-31222008

RESUMO

Pulmonary vein isolation (PVI) as interventional treatment for atrial fibrillation (AF) aims to eliminate arrhythmogenic triggers from the PVs. Improved signal detection facilitating a more robust electrical isolation might be associated with a better outcome. This retrospective cohort study compared PVI procedures using a novel high-density mapping system (HDM) with improved signal detection vs. age- and sex-matched PVIs using a conventional 3D mapping system (COM). Endpoints comprised freedom from AF and procedural parameters. In total, 108 patients (mean age 63.9 ± 11.2 years, 56.5% male, 50.9% paroxysmal AF) were included (n = 54 patients/group). Our analysis revealed that HDM was not superior regarding freedom from AF (mean follow-up of 494.7 ± 26.2 days), with one- and two-year AF recurrence rates of 38.9%/46.5% (HDM) and 38.9%/42.2% (COM), respectively. HDM was associated with reduction in fluoroscopy times (18.8 ± 10.6 vs. 29.8 ± 13.4 min; p < 0.01) and total radiation dose (866.0 ± 1003.3 vs. 1731.2 ± 1978.4 cGy; p < 0.01) compared to the COM group. HDM was equivalent but not superior to COM with respect to clinical outcome after PVI and resulted in reduced fluoroscopy time and radiation exposure. These results suggest that HDM-guided PVI is effective and safe for AF ablation. Potential benefits in comparison to conventional mapping systems, e.g. arrhythmia recurrence rates, have to be addressed in randomized trials.


Assuntos
Fibrilação Atrial/terapia , Veias Pulmonares/cirurgia , Idoso , Ablação por Cateter , Mapeamento Epicárdico/métodos , Feminino , Fluoroscopia/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Veias Pulmonares/fisiopatologia , Exposição à Radiação , Recidiva , Estudos Retrospectivos , Resultado do Tratamento
7.
Pneumologie ; 73(3): 143-180, 2019 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-30776835

RESUMO

The present 2019 S2k consensus guideline of the German Respiratory Society was written - in contrast to the predecessor more general S3 guidelines from 2004 and 2010 - for pneumologists, since 2014 the German College of General Practitioners and Family Physicians (DEGAM) published his own cough guidelines.The guideline contains 48 recommendations agreed by consensus and 16 statements, which are explained in the background text in the following nine chapters: epidemiology, physiology, classification, acute, subacute or chronic cough, diagnostics and therapy; an extra chapter was dedicated to chronic idiopathic cough. Further emphasis of the guideline is the physiology of cough in anticipation of the introduction of new drugs, as well as detailed treatises on cough triggered by affections in the upper respiratory tract or by gastroesophageal reflux. The guideline should provide the pneumologist with the latest knowledge from neighboring disciplines required for diagnosis and therapy of cough. The clinical chapters also contain a short summary, practical recommendations and a bibliography of their own. Three new, simplified algorithms for acute, subacute and chronic cough round off the Diagnostics chapter.


Assuntos
Tosse/diagnóstico , Tosse/terapia , Técnicas de Diagnóstico do Sistema Respiratório/normas , Refluxo Gastroesofágico , Guias de Prática Clínica como Assunto , Pneumologia/normas , Infecções Respiratórias/diagnóstico , Infecções Respiratórias/terapia , Doença Aguda , Adulto , Doença Crônica , Tosse/etiologia , Humanos , Infecções Respiratórias/etiologia , Sociedades Médicas
8.
Phys Chem Chem Phys ; 20(31): 20447-20458, 2018 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-30043030

RESUMO

Through theoretical analysis, we study relevant properties of some molecular structures formed by oligothiophenes (T) and dioctylfluorenes (F) units, commonly employed in the fabrication of different kinds of optical and electronic devices. For so, we first consider F-(T)n-F molecules with different numbers of thiophene rings (n). Among other characteristics, we calculate the dipole moment change between the ground and excited state (Δµge), a quantity that greatly influences the exciton dissociation and charge carrier mobility. We show that the planarity of the ground state geometry correlates Δµge to the exciton binding energy (Eb), with higher Δµge's corresponding to lower Eb's when n > 3. We also unveil a relevant dependence of Δµge with the odd-even parity of n and that Δµge assumes higher values when the molecule is composed by bithiophene (instead of simple thiophenes) moieties in the syn-conformation (with the two heteroatoms pointing in the same direction). From molecules results, we then address larger systems, formed by different oligomers of F-T copolymers containing blocks of dioctylfluorenes and bithiophenes (T2). We systematic investigate their electronic and structural properties as function of the composition ratio between the T2 and F moieties. Similar to the molecules, we deduce that the magnitude of Δµge is higher for the syn conformer of the T2 unit. Moreover, the highest values of Δµge are achieved when the number of the T2 increases relative to a fixed number of the F units in the mer. Such behaviors are in agreement and actually can qualitative explain measurements in the literature on the quantum efficiency of charge carrier generation in F-T copolymers. The present findings can be helpful in designing novel materials with improved photoelectric responses.

10.
Skin Res Technol ; 24(3): 445-449, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29405439

RESUMO

BACKGROUND: Mucous membranes may be affected by various diseases and the diagnostic accessibility is limited. Multiphoton laser tomography (MPT) is a useful tool for in vivo evaluation of superficial skin structures and might also be useful for the imaging of mucosa. OBJECTIVES: In order to investigate the suitability of MPT for the evaluation of mucous membranes, tissue samples of different donors and anatomical localizations have been imaged. METHODS: Human mucosa samples from the urinary bladder, palatine tonsil and ocular conjunctiva were investigated by MPT and subsequently compared with conventional histology. RESULTS: Horizontal images of the epithelium and the underlying connective tissue were obtained using the autofluorescence and second harmonics generation signals by MPT. The stratification of multilayered epithelium was consistently reproduced. Also inflammatory changes like lymphocytic infiltrates and widened intercellular spaces were imaged in some cases. CONCLUSION: Mucous tissue samples were obtained and MPT imaging was successfully performed. In the direct comparison with histology of the same tissue samples, the characteristic morphology of the epithelia was found. Further studies are necessary in order to compare images of healthy and diseased mucosal epithelium and the use of MPT for its evaluation in vivo.


Assuntos
Túnica Conjuntiva/anatomia & histologia , Mucosa/anatomia & histologia , Tonsila Palatina/anatomia & histologia , Bexiga Urinária/anatomia & histologia , Humanos , Lasers , Mucosa/patologia , Tonsila Palatina/patologia , Tomografia
11.
Phys Rev Lett ; 118(7): 077201, 2017 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-28256891

RESUMO

Bulk rutile RuO_{2} has long been considered a Pauli paramagnet. Here we report that RuO_{2} exhibits a hitherto undetected lattice distortion below approximately 900 K. The distortion is accompanied by antiferromagnetic order up to at least 300 K with a small room temperature magnetic moment of approximately 0.05µ_{B} as evidenced by polarized neutron diffraction. Density functional theory plus U (DFT+U) calculations indicate that antiferromagnetism is favored even for small values of the Hubbard U of the order of 1 eV. The antiferromagnetism may be traced to a Fermi surface instability, lifting the band degeneracy imposed by the rutile crystal field. The combination of high Néel temperature and small itinerant moments make RuO_{2} unique among ruthenate compounds and among oxide materials in general.

12.
Phys Rev Lett ; 117(23): 235701, 2016 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-27982606

RESUMO

The structural properties of LaCu_{6-x}Au_{x} are studied using neutron diffraction, x-ray diffraction, and heat capacity measurements. The continuous orthorhombic-monoclinic structural phase transition in LaCu_{6} is suppressed linearly with Au substitution until a complete suppression of the structural phase transition occurs at the critical composition x_{c}=0.3. Heat capacity measurements at low temperatures indicate residual structural instability at x_{c}. The instability is ferroelastic in nature, with density functional theory calculations showing negligible coupling to electronic states near the Fermi level. The data and calculations presented here are consistent with the zero temperature termination of a continuous structural phase transition suggesting that the LaCu_{6-x}Au_{x} series hosts an elastic quantum critical point.

13.
Astrobiology ; 16(12): 949-963, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27905827

RESUMO

Nitrogen is a major nutrient for all life on Earth and could plausibly play a similar role in extraterrestrial biospheres. The major reservoir of nitrogen at Earth's surface is atmospheric N2, but recent studies have proposed that the size of this reservoir may have fluctuated significantly over the course of Earth's history with particularly low levels in the Neoarchean-presumably as a result of biological activity. We used a biogeochemical box model to test which conditions are necessary to cause large swings in atmospheric N2 pressure. Parameters for our model are constrained by observations of modern Earth and reconstructions of biomass burial and oxidative weathering in deep time. A 1-D climate model was used to model potential effects on atmospheric climate. In a second set of tests, we perturbed our box model to investigate which parameters have the greatest impact on the evolution of atmospheric pN2 and consider possible implications for nitrogen cycling on other planets. Our results suggest that (a) a high rate of biomass burial would have been needed in the Archean to draw down atmospheric pN2 to less than half modern levels, (b) the resulting effect on temperature could probably have been compensated by increasing solar luminosity and a mild increase in pCO2, and (c) atmospheric oxygenation could have initiated a stepwise pN2 rebound through oxidative weathering. In general, life appears to be necessary for significant atmospheric pN2 swings on Earth-like planets. Our results further support the idea that an exoplanetary atmosphere rich in both N2 and O2 is a signature of an oxygen-producing biosphere. Key Words: Biosignatures-Early Earth-Planetary atmospheres. Astrobiology 16, 949-963.


Assuntos
Atmosfera , Clima , Exobiologia , Geologia , Modelos Teóricos , Nitrogênio/análise , Aerobiose , Anaerobiose , Carbono/análise , Planeta Terra , Fatores de Tempo
15.
Skin Res Technol ; 22(4): 437-442, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26853735

RESUMO

BACKGROUND: Multiphoton laser tomography (MPT) is a non-invasive technique that allows imaging of skin in vivo with very high spatial resolution and contrast. Previous work of our group has demonstrated that known morphological changes due to erythematogenic ultraviolet B (UVB) irradiation may be imaged in vivo by MPT. The present work investigated if morphological skin changes known from experimental erythematogenic UVB irradiation are also demonstrable in the course of a standard phototherapy regime that implies suberythematogenic doses of narrow band UVB. METHODS: Sixteen patients with psoriasis vulgaris receiving a narrow band phototherapy were included. A test field and a light-protected control field were measured with the multiphoton tomograph DermaInspect® at four time points: at baseline, the next day, after 3 days and at the day of the last exposure. RESULTS: In the course of the UVB phototherapy, spongiosis and pleomorphy as parameters of inflammation and cellular damage did not show significant changes. By contrast, an adaptive skin reaction with significant changes of keratosis and pigmentation was observed. CONCLUSION: MPT is a suitable technique for the investigation of qualitative and quantitative skin changes after UVB irradiation. After suberythematogenic UVB irradiation, photoadaptive skin changes, but no cellular damage can be observed with MPT.


Assuntos
Epiderme/diagnóstico por imagem , Epiderme/efeitos da radiação , Microscopia de Fluorescência por Excitação Multifotônica/métodos , Psoríase/diagnóstico por imagem , Psoríase/radioterapia , Terapia Ultravioleta/métodos , Adulto , Idoso , Epiderme/patologia , Feminino , Humanos , Lasers , Masculino , Pessoa de Meia-Idade , Psoríase/patologia , Tomografia Óptica/métodos , Resultado do Tratamento , Adulto Jovem
16.
Rofo ; 188(1): 53-9, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26695847

RESUMO

PURPOSE: The sacrum is a rare but unfavourable location for Aneurysmal Bone Cysts (ABCs), surgical procedures aiming to achieve local tumour control can be mutilating. Aim of this study was to evaluate whether selective arterial embolisation (AE) of ABC of the sacrum is an effective treatment and might be an alternative to surgical treatment options. MATERIALS AND METHODS: Between 2007 and 2011 six patients (mean age 13.7 years, range 8 - 18 years) with an ABC of the sacrum were treated by AE. Follow-up was performed by MRI-scans as well as clinical examination (mean 36.5 months, range 14 - 56 months). RESULTS: No treatment related complications have been observed. AE resulted in devascularisation of ABC and led to local tumour control in all patients. A partial consolidation was noticed in three patients. Pain relief was achieved in five of six patients, neurological deficits dissolved. In two patients more than one embolization was necessary. In one of these patients due to exacerbation of pain a surgical decompression was performed. CONCLUSION: AE of sacral ABCs can serve as an effective and safe treatment option. Thus it might be an alternative to potentially harmful surgical procedures. In case of ongoing tumour growth or pain recurrence AE can be repeated. In case of treatment failure surgical interventions are still possible. KEY POINTS: • transarterial embolisation enables local tumour control in sacral ABCs. • transarterial embolisation of sacral ABCs is a safe procedure. • in case of tumour progression repetitive embolisations are possible and effective.


Assuntos
Cistos Ósseos Aneurismáticos/terapia , Embolização Terapêutica/métodos , Sacro , Doenças da Coluna Vertebral/terapia , Adolescente , Cistos Ósseos Aneurismáticos/diagnóstico , Criança , Feminino , Seguimentos , Humanos , Imageamento por Ressonância Magnética , Masculino , Exame Neurológico , Medição da Dor , Estudos Retrospectivos , Resultado do Tratamento
17.
J Phys Condens Matter ; 27(39): 395401, 2015 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-26381161

RESUMO

Raman and Brillouin spectroscopy were used to probe optic and acoustic phonons in bulk 2H-WSe2. Raman spectra collected under different polarization conditions allowed assignment of spectral peaks to various first- and second-order processes. In contrast to some previous studies, a Raman peak at ∼259 cm(-1)was found not to be due to the A(1g) mode but to a second-order process involving phonons at either the M or K point of the Brillouin zone. Resonance effects due to excitons were also observed in the Raman spectra. Brillouin spectra of 2H-WSe2 contain a single peak doublet arising from a Rayleigh surface mode propagating with a velocity of [Formula: see text] m s(-1). This value is comparable to that estimated from Density Functional Theory calculations and also to those for the transition metal diselenides 2H-TaSe2 and 2H-NbSe2. Unlike these two materials, however, peaks arising from scattering via the elasto-optic mechanism were not observed in Brillouin spectra of WSe2 despite its lower opacity.

18.
Hautarzt ; 66(7): 511-21, 2015 Jul.
Artigo em Alemão | MEDLINE | ID: mdl-25943693

RESUMO

In recent years, multiphoton tomography (MPT) and multiphoton microscopy have gained increasing importance as noninvasive examination techniques in dermatology. MPT imaging is based on the specific stimulation of biogenic fluorophores. The induction of second harmonic generation is also used for imaging of particular molecules. Additional fluorescence staining or fluorescence markers are not necessary-an important advantage for the in vivo examination of human skin. Multiphoton techniques are not only appropriate for clinical diagnostics but also for biomedical research. MPT provides an optical biopsy depth up to 200 µm with subcellular resolution depicting cellular and extracellular structures. In combination with fluorescence lifetime imaging, additional information about the microenvironment, the energetic state and the cellular metabolism can be obtained. This review presents recent developments of MPT for the in vivo evaluation of physiological and pathological changes of skin and diagnostics of dermal diseases.


Assuntos
Microscopia de Fluorescência por Excitação Multifotônica/métodos , Imagem Molecular/métodos , Dermatopatias/metabolismo , Dermatopatias/patologia , Pele/metabolismo , Pele/patologia , Biomarcadores/metabolismo , Dermoscopia/métodos , Humanos , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos
20.
Skin Res Technol ; 21(2): 137-43, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25066913

RESUMO

BACKGROUND: In vivo multiphoton tomography (MPT) of human skin has become a valuable tool for non-invasive examination of morphological and biophysical skin properties and their alterations. So far, skin changes after UVB irradiation were mainly evaluated clinically and histologically. The present study aimed at non-invasive imaging of histological changes during acute UVB irradiation by multiphoton laser tomography. METHODS: In 10 volunteers, five areas were irradiated once with an erythematous UVB dose. Multiphoton measurements were performed four times, i.e. before irradiation (baseline), and 24, 48 and 72 h after irradiation, respectively. The data were evaluated for changes of epidermal pleomorphy, spongiosis, pigmentation and thickness. RESULTS: The four parameters were altered significantly by acute UVB irradiation, i.e. epidermal pleomorphy, spongiosis, pigmentation and thickness increased within 72 h after irradiation. CONCLUSION: Thus, the study has shown that typical epidermal changes induced by acute UVB irradiation can be evaluated by MPT.


Assuntos
Epiderme/lesões , Epiderme/patologia , Eritema/patologia , Microscopia de Fluorescência por Excitação Multifotônica/métodos , Lesões por Radiação/patologia , Raios Ultravioleta/efeitos adversos , Adulto , Idoso , Relação Dose-Resposta a Droga , Epiderme/efeitos da radiação , Eritema/etiologia , Feminino , Humanos , Lasers , Masculino , Pessoa de Meia-Idade , Doses de Radiação , Lesões por Radiação/etiologia , Tomografia Óptica/métodos , Adulto Jovem
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