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1.
Nano Lett ; 23(7): 2719-2725, 2023 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-37010208

RESUMO

Hot electron (HE) photocatalysis is one of the most intriguing fields of nanoscience, with a clear potential for technological impact. Despite much effort, the mechanisms of HE photocatalysis are not fully understood. Here we investigate a mechanism based on transient electron spillover on a molecule and subsequent energy release into vibrational modes. We use state-of-the-art real-time Time Dependent Density Functional Theory (rt-TDDFT), simulating the dynamics of a HE moving within linear chains of Ag or Au atoms, on which CO, N2, or H2O are adsorbed. We estimate the energy a HE can release into adsorbate vibrational modes and show that certain modes are selectively activated. The energy transfer strongly depends on the adsorbate, the metal, and the HE energy. Considering a cumulative effect from multiple HEs, we estimate this mechanism can transfer tenths of an eV to molecular vibrations and could play an important role in HE photocatalysis.

2.
Rep Pract Oncol Radiother ; 27(4): 744-753, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36196416

RESUMO

Background: Glioblastoma is the most common and aggressive primary tumor in adults. A narrative review of all the relevant papers known was conducted. Materials and methods: Reviews, clinical trials, and randomized controlled trials published from 1981 through September 2021 and written, or at least abstracted, in English were analyzed. Results: The standard of care for glioblastoma is the maximum safe resection possible, followed by radiation therapy and concurrent temozolomide (TMZ) and daily TMZ and tumor treatment fields (TTFields) after irradiation. There is no evidence to date of the benefit of brachytherapy, radiosurgery (SRS), fractional stereotactic radiotherapy (FSRT), and hyperfractionated radiotherapy over conventional external beam radiation therapy (EBRT) for the primary tumor. The assessment of age and performance status before treatment in the elderly enables hypofractionated radiotherapy. The research of tumor molecular signatures contributes to the choice of the best-targeted drug therapy. In recurrent glioblastoma, it is necessary to balance the risks and benefits of re-radiation and association with bevacizumab. Solid data confirming the role of immunotherapy in the treatment of malignant glioma are still lacking. Conclusions: Although the treatment of glioblastoma has evolved in terms of local control, mortality remains close to 12 months after diagnosis. To obtain better results and reduce recurrence, future research needs to investigate the frontiers of knowledge, such as the elucidation of the molecular mechanisms related to the tumor, the optimization of drugs to overcome the blood-brain barrier effectively, and the discovery of new therapies aimed at the heterogeneous profile of this neoplasm.

3.
J Chem Phys ; 154(22): 224114, 2021 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-34241221

RESUMO

We present LayerPCM, an extension of the polarizable-continuum model coupled to real-time time-dependent density-functional theory, for an efficient and accurate description of the electrostatic interactions between molecules and multilayered dielectric substrates on which they are physisorbed. The former are modeled quantum-mechanically, while the latter are treated as polarizable continua characterized by their dielectric constants. The proposed approach is purposely designed to simulate complex hybrid heterostructures with nano-engineered substrates including a stack of anisotropic layers. LayerPCM is suitable for describing the polarization-induced renormalization of frontier energy levels of the adsorbates in the static regime. Moreover, it can be reliably applied to simulating laser-induced ultrafast dynamics of molecules through the inclusion of electric fields generated by Fresnel-reflection at the substrate. Depending on the complexity of the underlying layer structure, such reflected fields can assume non-trivial shapes and profoundly affect the dynamics of the photo-excited charge carriers in the molecule. In particular, the interaction with the substrate can give rise to strong delayed fields, which lead to interference effects resembling those of multi-pulse-based spectroscopy. The robustness of the implementation and the above-mentioned features are demonstrated with a number of examples, ranging from intuitive models to realistic systems.

4.
J Chem Phys ; 153(18): 184114, 2020 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-33187410

RESUMO

Investigating nanoplasmonics in an explicit time-dependent perspective is a natural choice when light pulses are used and may also reveal aspects that are hidden in a frequency-based picture. In the past, we proposed a method time domain-boundary element method (TD-BEM) to simulate the time dependent polarization of nanoparticles based on a boundary element method that is particularly suitable to interface with a quantum atomistic description of nearby molecules. So far, however, metal dielectric functions in TD-BEM have been modeled through analytic expressions, such as those of Debye and Drude-Lorentz, which cannot account for multiple electronic resonances. Our approach allows us to include in the TD-BEM framework also the description of metals with complicate dielectric function profiles in the frequency domain. Particularly, among all metals, gold is a challenging case due to the presence of many transition frequencies. We applied our methods to different metals (gold, silver, and the less commonly investigated rhodium) and different shaped nanoparticles (spheres, ellipsoids, and cubes), the approach has been tested comparing TD-BEM and frequency domain BEM absorption spectra, and it has been used to investigate the time-dependent field acting locally close to nanoparticle vertices.

5.
J Chem Phys ; 152(12): 124119, 2020 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-32241132

RESUMO

Over the last few years, extraordinary advances in experimental and theoretical tools have allowed us to monitor and control matter at short time and atomic scales with a high degree of precision. An appealing and challenging route toward engineering materials with tailored properties is to find ways to design or selectively manipulate materials, especially at the quantum level. To this end, having a state-of-the-art ab initio computer simulation tool that enables a reliable and accurate simulation of light-induced changes in the physical and chemical properties of complex systems is of utmost importance. The first principles real-space-based Octopus project was born with that idea in mind, i.e., to provide a unique framework that allows us to describe non-equilibrium phenomena in molecular complexes, low dimensional materials, and extended systems by accounting for electronic, ionic, and photon quantum mechanical effects within a generalized time-dependent density functional theory. This article aims to present the new features that have been implemented over the last few years, including technical developments related to performance and massive parallelism. We also describe the major theoretical developments to address ultrafast light-driven processes, such as the new theoretical framework of quantum electrodynamics density-functional formalism for the description of novel light-matter hybrid states. Those advances, and others being released soon as part of the Octopus package, will allow the scientific community to simulate and characterize spatial and time-resolved spectroscopies, ultrafast phenomena in molecules and materials, and new emergent states of matter (quantum electrodynamical-materials).

6.
J Chem Phys ; 151(19): 194109, 2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31757146

RESUMO

In this work, we generalize the quantum optimal control theory (QOCT) of molecules subject to ultrashort laser pulses to the case of solvated systems, explicitly including the solvent dielectric properties in the system's quantum Hamiltonian. A reliable description of the solvent polarization is accounted for within the polarizable continuum model (PCM). The electron dynamics for the molecules in solution is coupled with the dynamics of the surrounding polarizable environment, which affects the features of the optimized laser pulse. To illustrate such effects, numerical applications of the developed method to the study of optimal population of selected excited states of two molecular solvated systems are presented and discussed.

7.
ACS Phys Chem Au ; 4(3): 202-225, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38800726

RESUMO

The rise of modern computer science enabled physical chemistry to make enormous progresses in understanding and harnessing natural and artificial phenomena. Nevertheless, despite the advances achieved over past decades, computational resources are still insufficient to thoroughly simulate extended systems from first principles. Indeed, countless biological, catalytic and photophysical processes require ab initio treatments to be properly described, but the breadth of length and time scales involved makes it practically unfeasible. A way to address these issues is to couple theories and algorithms working at different scales by dividing the system into domains treated at different levels of approximation, ranging from quantum mechanics to classical molecular dynamics, even including continuum electrodynamics. This approach is known as multiscale modeling and its use over the past 60 years has led to remarkable results. Considering the rapid advances in theory, algorithm design, and computing power, we believe multiscale modeling will massively grow into a dominant research methodology in the forthcoming years. Hereby we describe the main approaches developed within its realm, highlighting their achievements and current drawbacks, eventually proposing a plausible direction for future developments considering also the emergence of new computational techniques such as machine learning and quantum computing. We then discuss how advanced multiscale modeling methods could be exploited to address critical scientific challenges, focusing on the simulation of complex light-harvesting processes, such as natural photosynthesis. While doing so, we suggest a cutting-edge computational paradigm consisting in performing simultaneous multiscale calculations on a system allowing the various domains, treated with appropriate accuracy, to move and extend while they properly interact with each other. Although this vision is very ambitious, we believe the quick development of computer science will lead to both massive improvements and widespread use of these techniques, resulting in enormous progresses in physical chemistry and, eventually, in our society.

8.
Front Oncol ; 14: 1394116, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38807769

RESUMO

Synopsis: This is a systematic review and meta-analysis comparing surgical excision with percutaneous ultrasound-guided vacuum-assisted excision (US-VAE) for the treatment of benign phyllodes tumor (PT) using local recurrence (LR) as the endpoint. Objective: To determine the frequency of local recurrence (LR) of benign phyllodes tumor (PT) after ultrasound-guided vacuum-assisted excision (US-VAE) compared to the frequency of LR after surgical excision. Method: A systematic review and meta-analysis [following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standard] was conducted by comparing LR in women older than 18 years treated for benign PT by US-VAE compared with local surgical excision with at least 12 months of follow-up. Studies were retrieved from PubMed, Scopus, Web of Science, and Embase. The pooled effect measure used was the odds ratio (OR) of recurrence. Results: Five comparative prospective or retrospective observational studies published between January 1, 1992, and January 10, 2022, comparing surgical excision with percutaneous US-VAE for LR of benign PT met the selection criteria. Four were retrospective observational cohorts, and one was a prospective observational cohort. A total of 778 women were followed up. Of them, 439 (56.4%) underwent local surgical excision, and 339 (43.6%) patients had US-VAE. The median age of patients in the five studies ranged from 33.7 to 39 years; the median size ranged from 1.5 cm to 3.0 cm, and the median follow-up ranged from 12 months to 46.6 months. The needle gauge ranged from 7G to 11G. LR rates were not statically significant between US-VAE and surgical excision (41 of 339 versus 34 of 439; OR 1.3; p = 0.29). Conclusion: This meta-analysis suggests that using US-VAE for the removal of benign PT does not increase local regional recurrence and is a safe minimally invasive therapeutic option. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42022309782.

9.
Front Oncol ; 13: 1202544, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37388233

RESUMO

Purpose: This study, conducted during the COVID-19 crisis, primarily aimed to compare the acute toxicity between conventional fractionated radiation therapy (CF-RT) with hypofractionated radiation therapy (HF-RT) among patients who underwent breast-conserving surgery or mastectomy in whom breast or chest wall and regional nodal irradiation (RNI) were indicated. The secondary endpoints were both acute and subacute toxicity, cosmesis, quality of life, and lymphedema features. Methods: In this open and non-inferiority randomized trial, patients (n = 86) were randomly allocated 2:1 in the CF-RT arm (n = 33; 50 Gy/25 fractions ± sequential boost [10 Gy/5 fractions]) versus the HF-RT arm (n = 53; 40 Gy/15 fractions ± concomitant boost [8 Gy/15 fractions]). Toxic effects and cosmesis evaluation used the Common Terminology Criteria for Adverse Events, version 4.03 (CTCAE) and the Harvard/National Surgical Adjuvant Breast and Bowel Project (NSABP)/Radiation Therapy Oncology Group (RTOG) scale. For the patient-reported quality of life (QoL), the European Organisation for Research and Treatment of Cancer quality of life questionnaire (EORTC QLQ-C30) and the breast cancer-specific supplementary questionnaire (QLQ-BR23) were used. Lymphedema was assessed by comparing volume differences between the affected and contralateral arms using the Casley-Smith formula. Results: Grade 2 and grade 3 dermatitis were lower with HF-RT than with CF-RT (28% vs. 52%, and 0% vs. 6%, respectively; p = 0.022). HF-RT had a lower rate of grade 2 hyperpigmentation (23% vs. 55%; p = 0.005), compared to CF-RT. No other differences in overall rates of physician-assessed grade 2 or higher and grade 3 or higher acute toxicity between HF-RT and CF-RT were registered. There was no statistical difference between groups regarding cosmesis, lymphedema rate (13% vs. 12% HF-RT vs. CF-RT; p = 1.000), and functional and symptom scales, during both the irradiation period and after 6 months of the end of treatment. The results revealed that the subset of patients up to 65 years or older did not show a statistical difference between both arm fractionation schedules (p > 0.05) regarding skin rash, fibrosis, and lymphedema. Conclusion: HF-RT was non-inferior to CF-RT, and moderate hypofractionation showed lower rates of acute toxicity, with no changes in quality-of-life outcomes. Clinical trial registration: ClinicalTrials.gov, identifier NCT40155531.

10.
Rev Bras Ginecol Obstet ; 44(6): 573-577, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35617949

RESUMO

OBJECTIVE: The present study aimed to develop a useful mathematical model that predicts the age at which premature ovarian insufficiency might occur after teletherapy radiation. A diagnosis of premature or early menopause has physical and psychological consequences, so women may need support and long-term medical follow-up. METHODS: To correlate ovarian radiation dose with ovarian function, we used the formula described by Wallace et al.: √g(z) = 10(2-0,15z), where "g(z)" and "z" represent oocyte survival rate and the radiation dose (in Gray), respectively. By simulating different ages and doses, we observed a pattern that could be used to simplify the relationship between radiation dose and remaining time of ovarian function. RESULTS: We obtained a linear function between ovarian radiation dose and loss of ovarian function (LOF) that is the percentage of decrease in the time to the ovarian failure compared with the time expected for a woman at the same age without irradiation exposition. For patients < 40 years old and with ovarian radiation doses < 5 Gy, the equation LOF = 2.70 + (11.08 x Dose) can be applied to estimate the decrease in time to premature ovarian insufficiency. CONCLUSION: The present study reports a practicable theoretical method to estimate the loss of ovarian function. These findings can potentially improve the management and counseling of young women patients submitted to radiotherapy during their reproductive years.


OBJETIVO: O presente estudo teve como objetivo desenvolver um modelo matemático útil que prediz a idade na qual a insuficiência ovariana prematura pode ocorrer após a radioterapia externa (teleterapia). O diagnóstico de menopausa prematura ou precoce tem consequências físicas e psicológicas; portanto, as mulheres podem precisar de apoio e acompanhamento médico de longo prazo. MéTODOS: Para correlacionar a dose de radiação ovariana com a função ovariana, foi usada a fórmula descrita por Wallace et al.: √g(z) = 10(2-0,15z), na qual "g(z)" e "z" representam a taxa de sobrevivência do oócito e a dose de radiação (em Gray), respectivamente. Ao simular diferentes idades e doses, observamos um padrão que poderia ser usado para simplificar a relação entre a dose de radiação e o tempo restante da função ovariana. RESULTADOS: Obtivemos uma função linear entre a dose de radiação ovariana e a perda da função ovariana (LOF, na sigla em inglês) que é a porcentagem de diminuição no tempo até a falência ovariana em relação ao tempo esperado para uma mulher da mesma idade sem exposição à radiação. Para pacientes < 40 anos de idade e com doses de radiação ovariana < 5 Gy, a equação LOF = 2,70 + (11,08 x Dose) pode ser aplicada para estimar a redução no tempo até a insuficiência ovariana. CONCLUSãO: O presente estudo relata um método teórico viável para estimar a perda da função ovariana. Estes achados podem melhorar potencialmente o manejo e o aconselhamento de pacientes jovens submetidas à radioterapia durante seus anos reprodutivos.


Assuntos
Insuficiência Ovariana Primária , Feminino , Humanos , Oócitos , Insuficiência Ovariana Primária/etiologia
11.
Nanoscale ; 13(12): 6005-6015, 2021 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-33710244

RESUMO

Coupling of molecular emitters to plasmon resonances in metal nanostructures has long been investigated to control the light-matter interaction at the nanoscale. The emergence of different coupling behaviors can be governed by the various combinations of emitters and plasmonic substrates, as well as the spatial arrangement of the individual components. Here colloidal assembly methods are exploited to prepare a responsive nanosystem where two sets of plexcitonic resonances in different coupling regimes can be selectively switched on and off, acting on external conditions such as concentration and presence of anions. The two sets of plexciton resonances are built exploiting the strong coupling between cationic gold nanoparticles and the same molecular moiety, an anionic porphyrin, in different aggregation states. When both plexciton resonances are simultaneously activated in the system, evidence for a plexciton relaxation cascade has been found in photoluminescence experiments. These findings have fundamental implications for achieving control over energy flow at the nanoscale.

12.
Front Chem ; 8: 340, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32457870

RESUMO

The fully atomistic model, ωFQ, based on textbook concepts (Drude theory, electrostatics, quantum tunneling) and recently developed by some of the present authors in Nanoscale, 11, 6004-6015 is applied to the calculation of the optical properties of complex Na, Ag, and Au nanostructures. In ωFQ, each atom of the nanostructures is endowed with an electric charge that can vary according to the external electric field. The electric conductivity between nearest atoms is modeled by adopting the Drude model, which is reformulated in terms of electric charges. Quantum tunneling effects are considered by letting the dielectric response of the system arise from atom-atom conductivity. ωFQ is challenged to reproduce the optical response of metal nanoparticles of different sizes and shapes, and its performance is compared with continuum Boundary Element Method (BEM) calculations.

13.
J Chem Theory Comput ; 15(4): 2306-2319, 2019 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-30860829

RESUMO

We develop an extension of the time-dependent equation-of-motion formulation of the polarizable continuum model (EOM-TDPCM) to introduce nonequilibrium cavity field effects in quantum mechanical calculations of solvated molecules subject to time-dependent electric fields. This method has been implemented in Octopus, a state-of-the-art code for real-space, real-time time-dependent density functional theory (RT-TDDFT) calculations. To show the potential of our methodology, we perform EOM-TDPCM/RT-TDDFT calculations of trans-azobenzene in water and in other model solvents with shorter relaxation times. Our results for the optical absorption spectrum of trans-azobenzene show (i) that cavity field effects have a clear impact in the overall spectral shape and (ii) that an accurate description of the solute shape (as the one provided within PCM) is key to correctly account for cavity field effects.

14.
World Neurosurg ; 111: 109-114, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29274446

RESUMO

BACKGROUND: Trastuzumab emtansine, an antibody-drug conjugate commonly abbreviated as T-DM1, is accepted as effective therapy for trastuzumab-resistant metastatic HER2-positive breast cancer. T-DM1 significantly increases progression-free and overall survival when compared with lapatinib plus capecitabine in patients with HER2-positive breast cancer previously treated with trastuzumab and a taxane. Among the common side effects related to T-DM1, thrombocytopenia and mucosal hemorrhage are seen, although they are infrequently judged to be clinically significant. Intracranial hemorrhages are extremely rare, and only 3 cases of hematomas have been reported in association with T-DM1 and remote radiotherapy, 2 of them with progressive enlargement. OBJECTIVE: Herein we describe a patient who presented with a cerebellar hematoma that progressively enlarged over 8 months during treatment with T-DM1 and only a few months after whole-brain radiation therapy plus a stereotactic radiosurgery boost for a HER2-positive breast cancer cerebellar metastasis. The pathology of the hematoma was similar to that in previous cases and suggested a unique pathophysiology related to an interaction between T-DMI and radiation therapy. CONCLUSIONS: A progressively enlarging intraparenchymal hematoma can be seen just a few months after delivery of radiation therapy for a metastatic brain lesion in HER2-positive breast cancer patients who are receiving T-DM1. In such patients, even a small focus of hemorrhage on magnetic resonance images should prompt close follow-up with serial imaging.


Assuntos
Doenças Cerebelares/etiologia , Hematoma/etiologia , Maitansina/análogos & derivados , Trastuzumab/efeitos adversos , Ado-Trastuzumab Emtansina , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/secundário , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Doenças Cerebelares/diagnóstico por imagem , Angiografia Cerebral , Terapia Combinada/efeitos adversos , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Hematoma/diagnóstico por imagem , Humanos , Angiografia por Ressonância Magnética , Maitansina/efeitos adversos , Maitansina/uso terapêutico , Pessoa de Meia-Idade , Radiocirurgia , Radioterapia/efeitos adversos , Receptor ErbB-2/genética , Trastuzumab/uso terapêutico
15.
Rev. bras. ginecol. obstet ; 44(6): 573-577, June 2022. graf
Artigo em Inglês | LILACS | ID: biblio-1394799

RESUMO

Abstract Objective The present study aimed to develop a useful mathematical model that predicts the age at which premature ovarian insufficiency might occur after teletherapy radiation. A diagnosis of premature or early menopause has physical and psychological consequences, so women may need support and long-term medical follow-up. Methods To correlate ovarian radiation dose with ovarian function, we used the formula described by Wallace et al.: √g(z) = 10(2-0,15z), where "g(z)" and "z" represent oocyte survival rate and the radiation dose (in Gray), respectively. By simulating different ages and doses, we observed a pattern that could be used to simplify the relationship between radiation dose and remaining time of ovarian function. Results We obtained a linear function between ovarian radiation dose and loss of ovarian function (LOF) that is the percentage of decrease in the time to the ovarian failure compared with the time expected for a woman at the same age without irradiation exposition. For patients <40 years old and with ovarian radiation doses < 5 Gy, the equation LOF = 2.70 + (11.08 × Dose) can be applied to estimate the decrease in time to premature ovarian insufficiency. Conclusion The present study reports a practicable theoretical method to estimate the loss of ovarian function. These findings can potentially improve the management and counseling of young women patients submitted to radiotherapy during their reproductive years.


Resumo Objetivo O presente estudo teve como objetivo desenvolver um modelo matemático útil que prediz a idade na qual a insuficiência ovariana prematura pode ocorrer após a radioterapia externa (teleterapia). O diagnóstico de menopausa prematura ou precoce tem consequências físicas e psicológicas; portanto, as mulheres podem precisar de apoio e acompanhamento médico de longo prazo. Métodos Para correlacionar a dose de radiação ovariana com a função ovariana, foi usada a fórmula descrita por Wallace et al.: √g(z) = 10(2-0,15z), na qual "g(z)" e "z" representam a taxa de sobrevivência do oócito e a dose de radiação (em Gray), respectivamente. Ao simular diferentes idades e doses, observamos um padrão que poderia ser usado para simplificar a relação entre a dose de radiação e o tempo restante da função ovariana. Resultados Obtivemos uma função linear entre a dose de radiação ovariana e a perda da função ovariana (LOF, na sigla em inglês) que é a porcentagem de diminuição no tempo até a falência ovariana em relação ao tempo esperado para uma mulher da mesma idade sem exposição à radiação. Para pacientes<40 anos de idade e com doses de radiação ovariana < 5 Gy, a equação LOF = 2,70 + (11,08 × Dose) pode ser aplicada para estimar a redução no tempo até a insuficiência ovariana. Conclusão O presente estudo relata um método teórico viável para estimar a perda da função ovariana. Estes achados podem melhorar potencialmente o manejo e o aconselhamento de pacientes jovens submetidas à radioterapia durante seus anos reprodutivos.


Assuntos
Humanos , Feminino , Testes de Função Ovariana , Ovário/efeitos da radiação , Insuficiência Ovariana Primária
16.
RSC Adv ; 6(106): 104648-104656, 2016 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-28066545

RESUMO

Resonance energy transfer (RET) is an inherently anisotropic process. Even the simplest, well-known Förster theory, based on the transition dipole-dipole coupling, implicitly incorporates the anisotropic character of RET. In this theoretical work, we study possible signatures of the fundamental anisotropic character of RET in hybrid nanomaterials composed of a semiconductor nanoparticle (NP) decorated with molecular dyes. In particular, by means of a realistic kinetic model, we show that the analysis of the dye photoluminescence difference for orthogonal input polarizations reveals the anisotropic character of the dye-NP RET which arises from the intrinsic anisotropy of the NP lattice. In a prototypical core/shell wurtzite CdSe/ZnS NP functionalized with cyanine dyes (Cy3B), this difference is predicted to be as large as 75% and it is strongly dependent in amplitude and sign on the dye-NP distance. We account for all the possible RET processes within the system, together with competing decay pathways in the separate segments. In addition, we show that the anisotropic signature of RET is persistent up to a large number of dyes per NP.

17.
Knee ; 21(2): 402-5, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24238652

RESUMO

BACKGROUND: One of the most frequent reasons for total knee arthroplasty late failure is osteolysis. It has been related to foreign body reaction to polyethylene particles. The aim of this study is to analyse the number, size and morphology of polyethylene particles in synovial fluid in total knee arthroplasty revision and correlate them to the pathology and the degree of osteolysis. METHODS: Synovial fluid was obtained in 12 patients before the revision total knee arthroplasty. Polyethylene particles were isolated and analysed through scanning electron microscopy. Samples of synovial tissue were analysed with optical microscopy while considering the parameters of particles and histiocytic infiltration. Osteolysis was analysed with plain radiography and the macroscopic aspect during surgery. RESULTS: The statistical analysis showed a significant correlation between a high concentration of polyethylene particles in synovial fluid and a high degree of osteolysis. The concentration of particles in synovial fluid also showed a significant correlation with a high degree of particles and histiocytes in the histological analysis. There was a relationship between the size of particles and the degree of osteolysis. No relationship was found between the shape of the particles and the histological findings or the degree of osteolysis. CONCLUSIONS: In an "in vivo" TKA scenario, the presence of a high concentration of polyethylene particles in the synovial fluid seems to be the cause of a highly active foreign body histological reaction, with an increased number of histiocytes, which seems to be the cause of a significant degree of osteolysis around the implant.


Assuntos
Reação a Corpo Estranho/etiologia , Prótese do Joelho/efeitos adversos , Osteólise/etiologia , Polietileno/análise , Falha de Prótese , Líquido Sinovial/química , Idoso , Idoso de 80 Anos ou mais , Artroplastia do Joelho , Feminino , Reação a Corpo Estranho/metabolismo , Reação a Corpo Estranho/patologia , Histiócitos/metabolismo , Humanos , Articulação do Joelho/diagnóstico por imagem , Articulação do Joelho/cirurgia , Masculino , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade , Osteólise/diagnóstico por imagem , Osteólise/patologia , Tamanho da Partícula , Estudos Prospectivos , Radiografia , Reoperação , Líquido Sinovial/metabolismo
18.
Brachytherapy ; 12(3): 235-9, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-22436517

RESUMO

PURPOSE: To evaluate outcomes in patients with posterior choroidal melanoma treated with ruthenium ((106)Ru) brachytherapy. METHODS AND MATERIALS: A retrospective single institutional analysis of 83 of 94 consecutive patients who underwent (106)Ru brachytherapy was performed. Disease was mainly staged as small- and medium-sized nonmetastatic melanoma. The main parameters evaluated were tumor control (local control [LC] and progression-free survival [PFS]) and ocular preservation (enucleation-free survival [EFS]). Besides, functional evaluation was performed and complications were described. RESULTS: The median follow-up was 39 (6-83) months. The median values of height and maximal basal diameter were 4.3 and 9.3mm, respectively. Median apical and basal doses were 100 and 307Gy, respectively. The actuarial 2-year LC, PFS, and EFS were 96.2%, 96.2%, and 95.5%, respectively. Actuarial 5-year LC, PFS, and EFS were 93.6%, 93.6%, and 84.1%, respectively. Preinsertion visual acuity (VA) maintenance was 34% (equal or better than before treatment). Approximately 56% of patients stayed with a minimum functional VA of 0.1 or more, from whom more than half stayed with 0.5 or more. Cataract was seen in 16% of treated eyes, and glaucoma was the rarest complication, with an incidence of 3%. CONCLUSIONS: Small- and medium-sized choroidal melanomas can be adequately treated with (106)Ru brachytherapy, with high rates of tumor control and ocular preservation. Moreover, acceptable incidence of complications such as glaucoma and cataract are seen, and a reasonable part of patients stay with a minimum functional VA.


Assuntos
Braquiterapia/métodos , Neoplasias da Coroide/radioterapia , Melanoma/radioterapia , Lesões por Radiação/prevenção & controle , Radioisótopos de Rutênio/uso terapêutico , Acuidade Visual , Adulto , Idoso , Idoso de 80 Anos ou mais , Brasil/epidemiologia , Neoplasias da Coroide/diagnóstico , Neoplasias da Coroide/mortalidade , Intervalo Livre de Doença , Feminino , Seguimentos , Humanos , Incidência , Masculino , Melanoma/diagnóstico , Melanoma/mortalidade , Pessoa de Meia-Idade , Prognóstico , Lesões por Radiação/epidemiologia , Estudos Retrospectivos , Taxa de Sobrevida/tendências , Fatores de Tempo , Adulto Jovem
19.
Cien Saude Colet ; 17(11): 3047-56, 2012 Nov.
Artigo em Português | MEDLINE | ID: mdl-23175311

RESUMO

The demand for and use of health services results from a set of determinants that include socioeconomic, demographic and health characteristics and organization of the supply of services. The scope of this paper is to define access to and use of the health services in two Family Health Units (FHUs) of the sanitary district of Liberdade, establishing the pattern of use and identifying factors related to socio-organizational and geographical access. A cross-sectional population-based survey was conducted on individuals aged between 20 and 75 resident in the area covered by the two FHUs. Access to health services was analyzed based on the socio-organizational and geographic characteristics and according to the demand for medical appointments. Over 50% of respondents sought the service of FHUs and of these 78.7% reported attending the appointment. With respect to organizational access, problems were encountered, such as long waiting times for consultation. Geographical barriers were ascertained in the use of FHUs, but these did not prevent the realization of medical consultation. The use of FHUs was higher among people with lower socioeconomic status.


Assuntos
Acessibilidade aos Serviços de Saúde , Atenção Primária à Saúde/estatística & dados numéricos , Adulto , Idoso , Brasil , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
20.
J Prev Interv Community ; 38(3): 244-59, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20603760

RESUMO

Developmental research in the social-cognitive tradition has provided ample evidence for systematic relations between adolescents' social-cognitive development and mental health problems; both are set within an adolescent's ecology. However, appropriate assessment procedures for school-based prevention reflecting this differential knowledge are largely absent. The aim of this article is to outline the development and application of a new, holistic assessment procedure for youth that includes indicators of adolescents' social-cognitive development and related resiliencies, risks, and relationships. Using quantitative and qualitative data from the ongoing, school-based RALLY prevention program, we illustrate the development and efficiency of this holistic assessment tool within a developmental-ecological framework. This article argues a holistic assessment tool can guide the prevention services to address the individual needs of adolescents and to ideally support their developmental and learning capacity. Finally, the implications for practitioners are discussed.


Assuntos
Desenvolvimento Infantil , Avaliação de Programas e Projetos de Saúde/métodos , Instituições Acadêmicas , Adolescente , Criança , Feminino , Humanos , Entrevistas como Assunto , Masculino , Inquéritos e Questionários
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