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1.
Nanomaterials (Basel) ; 14(8)2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38668178

RESUMO

In this report, we present the results on the physicochemical characterization of cadmium telluride quantum dots (QDs) stabilized with glutathione and prepared by optimizing the synthesis conditions. An excellent control of emissions and the composition of the nanocrystal surface for its potential application in monoclonal antibody and biomarker testing was achieved. Two samples (QDYellow, QDOrange, corresponding to their emission colors) were analyzed by dynamic light scattering (DLS), and their hydrodynamic sizes were 6.7 nm and 19.4 nm, respectively. Optical characterization by UV-vis absorbance spectroscopy showed excitonic peaks at 517 nm and 554 nm. Photoluminescence spectroscopy indicated that the samples have a maximum intensity emission at 570 and 606 nm, respectively, within the visible range from yellow to orange. Infrared spectroscopy showed vibrational modes corresponding to the functional groups OH-C-H, C-N, C=C, C-O, C-OH, and COOH, which allows for the formation of functionalized QDs for the manufacture of biomarkers. In addition, the hydrodynamic radius, zeta potential, and approximate molecular weight were determined by dynamic light scattering (DLS), electrophoretic light scattering (ELS), and static light scattering (SLS) techniques. Size dispersion and the structure of nanoparticles was obtained by Transmission Electron Microscopy (TEM) and by X-ray diffraction. In the same way, we calculated the concentration of Cd2+ ions expressed in mg/L by using the Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-OES). In addition to the characterization of the nanoparticles, the labeling of murine myeloid cells was carried out with both samples of quantum dots, where it was demonstrated that quantum dots can diffuse into these cells and connect mostly with the cell nucleus.

2.
Cureus ; 16(3): e55645, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38586623

RESUMO

Endoscopic submucosal dissection (ESD) is increasingly being utilized for the resection of superficial gastrointestinal neoplasms. However, the long procedure time poses a technical challenge for conventional ESD (C-ESD). Traction-assisted ESD (T-ESD) was developed to facilitate the procedure by reducing its duration. This study compares the efficacy and safety of C-ESD versus T-ESD in the treatment of esophageal, gastric, and colorectal neoplasms. Nine randomized controlled trials (RCTs) were analyzed. Traction-assisted ESD exhibited shorter mean dissection times for the esophagus and colorectal regions and lower perforation rates in colorectal cases. No significant differences were observed in en bloc resection or bleeding rates. Traction-assisted ESD proves to be more efficient in mean procedure time for esophageal and colorectal cases and safer in perforation rates for colorectal cases, but similar rates are noted for en bloc resection or bleeding.

4.
Pest Manag Sci ; 80(6): 2892-2904, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38411441

RESUMO

BACKGROUND: Given the chemical diversity within stink bugs scent glands, they can be convenient models for bioprospecting novel pest control products. Preliminary behaviour observations indicated that adult Mictis fuscipes stink bugs secrete liquid droplets when defending against Solenopsis invicta fire ants, killing them within minutes. Hence, this study aimed to analyse the chemical composition of the metathoracic scent gland secretions of M. fuscipes adults, as well as assess their biological activities against fire ants. RESULTS: Bioassaying fire ants against secretions of several local stink bugs confirmed that the defensive secretions of two Mictis species are significantly more lethal, where M. fuscipes was the most lethal. Volatiles chromatography analysis indicated the secretions of female and male M. fuscipes stink bugs contains 20 and 26 components, respectively, chiefly hexanoic acid and hexyl hexanoate. Five compounds were consistently present in the secretion of female adults: hexyl hexanoate, hexanoic acid, hexyl acetate, hexyl butyrate, and eugenol. These yielded a strong electrophysiological antennal (EAD) response from S. invicta workers, female alates and males, where hexyl acetate showed the strongest response. The combination of these five compounds proved strongly repellent to S. invicta. When tested singly, hexanoic acid, hexyl butyrate, hexyl hexanoate, and eugenol were repellent to S. invicta, but hexyl acetate seemed slightly attractive. Additionally, the same mixture of five components exhibited strong contact and fumigant toxicity towards S. invicta workers, eugenol being the strongest. CONCLUSION: Defensive chemicals of M. fuscipes exhibit robust biological activity against S. invicta and could inspire the development of biopesticides. © 2024 Society of Chemical Industry.


Assuntos
Formigas , Glândulas Odoríferas , Animais , Feminino , Masculino , Formigas/efeitos dos fármacos , Glândulas Odoríferas/química , Heterópteros/efeitos dos fármacos , Heterópteros/fisiologia , Hemípteros/efeitos dos fármacos , Hemípteros/fisiologia , Formigas Lava-Pés
6.
J Appl Clin Med Phys ; : e14303, 2024 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-38377378

RESUMO

PURPOSE: A workflow/planning strategy delivering low-dose radiation therapy (LDRT) (1 Gy) to all polymetastatic diseases using conventional planning/delivery (Raystation/Halcyon = "conventional") and the AI-based Ethos online adaptive RT (oART) platform is developed/evaluated. METHODS: Using retrospective data for ten polymetastatic non-small cell lung cancer patients (5-52 lesions each) with PET/CTs, gross tumor volumes (GTVs) were delineated using PET standardized-uptake-value (SUV) thresholding. A 1 cm uniform expansion of GTVs to account for setup/contour uncertainty and organ motion-generated planning target volumes (PTVs). Dose optimization/calculation used the diagnostic CT from PET/CT. Dosimetric objectives were: Dmin,0.03cc ≥ 95% (acceptable variation (Δ) ≥ 90%), V100% ≥ 95% (Δ ≥ 90%), and D0.03cc ≤ 120% (Δ ≤ 125%). Additionally, online adaptation was simulated. When available, subsequent diagnostic CT was used to represent on-treatment CBCT. Otherwise, the CT from PET/CT used for initial planning was deformed to simulate clinically representative changes. RESULTS: All initial plans generated, both for Raystation and Ethos, achieved clinical goals within acceptable variation. For all patients, Dmin,0.03cc ≥ 95%, V100% ≥ 95%, and D0.03cc ≤ 120% goals were achieved for 84.8%/99.5%, 97.7%/98.7%, 97.4%/92.3%, in conventional/Ethos plans, respectively. The ratio of 50% isodose volume to PTV volume (R50% ), maximum dose at 2 cm from PTV (D2cm ), and the ratio of the 100% isodose volume to PTV volume (conformity index) in Raystation/Ethos plans were 7.9/5.9; 102.3%/88.44%; and 0.99/1.01, respectively. In Ethos, online adapted plans maintained PTV coverage whereas scheduled plans often resulted in geographic misses due to changes in tumor size, patient position, and body habitus. The average total duration of the oART workflow was 26:15 (min:sec) ranging from 6:43 to 57:30. The duration of each oART workflow step as a function of a number of targets showed a low correlation coefficient for influencer generation and editing (R2  = 0.04 and 0.02, respectively) and high correlation coefficient for target generation, target editing and plan generation (R2  = 0.68, 0.63 and 0.69, respectively). CONCLUSIONS: This study demonstrates feasibility of conventional planning/treatment with Raystation/Halcyon and highlights efficiency gains when utilizing semi-automated planning/online-adaptive treatment with Ethos for immunostimulatory LDRT conformally delivered to all sites of polymetastatic disease.

8.
Bull Math Biol ; 86(2): 19, 2024 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-38238433

RESUMO

Longitudinal tumour volume data from head-and-neck cancer patients show that tumours of comparable pre-treatment size and stage may respond very differently to the same radiotherapy fractionation protocol. Mathematical models are often proposed to predict treatment outcome in this context, and have the potential to guide clinical decision-making and inform personalised fractionation protocols. Hindering effective use of models in this context is the sparsity of clinical measurements juxtaposed with the model complexity required to produce the full range of possible patient responses. In this work, we present a compartment model of tumour volume and tumour composition, which, despite relative simplicity, is capable of producing a wide range of patient responses. We then develop novel statistical methodology and leverage a cohort of existing clinical data to produce a predictive model of both tumour volume progression and the associated level of uncertainty that evolves throughout a patient's course of treatment. To capture inter-patient variability, all model parameters are patient specific, with a bootstrap particle filter-like Bayesian approach developed to model a set of training data as prior knowledge. We validate our approach against a subset of unseen data, and demonstrate both the predictive ability of our trained model and its limitations.


Assuntos
Modelos Biológicos , Neoplasias , Humanos , Teorema de Bayes , Conceitos Matemáticos , Modelos Teóricos , Neoplasias/radioterapia
9.
An Acad Bras Cienc ; 95(suppl 2): e20220956, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38198397

RESUMO

Malaria is the most important parasitic disease worldwide. In 2019, more than 679,441 cases of malaria were reported in the American region. During this study, Argentina was in malaria pre-elimination autochthonous transmission phase with the aim of being declared as malaria-free country. The aim of this work was to assess the influence of remote sensing spectral indices (NDVI, NDWI) and climatic variables (temperature, relative humidity and precipitation) on the distribution and abundance of Anopheles mosquitoes, in four localities with different degrees of anthropogenic disturbance and with previous malaria cases records located , in a historical malarious area in northeastern of Argentina. Between June 2012 and July 2014, mosquitoes were collected. We collected 535 Anopheles adult mosquitoes. Anopheles strodei s.l. was the most abundant species. The greatest richness, diversity and abundance of species were registered in wild and semi-urban environments. The abundance of Anopheles presented a negative association with relative humidity and mean temperature, but positive with mean maximum temperature. The most important variables determining Anopheles total abundance and distribution were NDWI Index and distance to vegetation. The abundance of An. strodei s.l., was positive associated with water areas whereas the NDVI Index was negatively associated.


Assuntos
Anopheles , Malária , Animais , Argentina , Temperatura , Água
10.
Radiat Res ; 201(2): 93-103, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38171489

RESUMO

The pervasiveness of deep space radiation remains a confounding factor for the transit of humans through our solar system. Spacecraft shielding both protects astronauts but also contributes to absorbed dose through galactic cosmic ray interactions that produce secondary particles. The resultant biological effects drop to a minimum for aluminum shielding around 20 g/cm2 but increase with additional shielding. The present work evaluates for the first time, the impact of secondary pions on central nervous system functionality. The fractional pion dose emanating from thicker shielded spacecraft regions could contribute up to 10% of the total absorbed radiation dose. New results from the Paul Scherrer Institute have revealed that low dose exposures to 150 MeV positive and negative pions, akin to a Mars mission, result in significant, long-lasting cognitive impairments. These surprising findings emphasize the need to carefully evaluate shielding configurations to optimize safe exposure limits for astronauts during deep space travel.


Assuntos
Radiação Cósmica , Mésons , Proteção Radiológica , Voo Espacial , Humanos , Astronave , Radiação Cósmica/efeitos adversos , Proteção Radiológica/métodos , Astronautas , Cognição , Doses de Radiação
11.
Phys Med Biol ; 69(1)2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-37995363

RESUMO

Objective.To study the secondary neutrons generated by primary oxygen beams for cancer treatment and compare the results to those from primary protons, helium, and carbon ions. This information can provide useful insight into the positioning of neutron detectors in phantom for future experimental dose assessments.Approach.Mono-energetic oxygen beams and spread-out Bragg peaks were simulated using the Monte Carlo particle transport codesFLUktuierende KAskade, tool for particle simulation, and Monte Carlo N-Particle, with energies within the therapeutic range. The energy and angular distribution of the secondary neutrons were quantified.Main results.The secondary neutron spectra generated by primary oxygen beams present the same qualitative trend as for other primary ions. The energy distributions resemble continuous spectra with one peak in the thermal/epithermal region, and one other peak in the fast/relativistic region, with the most probable energy ranging from 94 up to 277 MeV and maximum energies exceeding 500 MeV. The angular distribution of the secondary neutrons is mainly downstream-directed for the fast/relativistic energies, whereas the thermal/epithermal neutrons present a more isotropic propagation. When comparing the four different primary ions, there is a significant increase in the most probable energy as well as the number of secondary neutrons per primary particle when increasing the mass of the primaries.Significance.Most previous studies have only presented results of secondary neutrons generated by primary proton beams. In this work, secondary neutrons generated by primary oxygen beams are presented, and the obtained energy and angular spectra are added as supplementary material. Furthermore, a comparison of the secondary neutron generation by the different primary ions is given, which can be used as the starting point for future studies on treatment plan comparison and secondary neutron dose optimisation. The distal penumbra after the maximum dose deposition appears to be a suitable location for in-phantom dose assessments.


Assuntos
Nêutrons , Terapia com Prótons , Terapia com Prótons/métodos , Prótons , Dosagem Radioterapêutica , Método de Monte Carlo
12.
J Appl Clin Med Phys ; 25(3): e14202, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37942993

RESUMO

Quality of organ at risk (OAR) autosegmentation is often judged by concordance metrics against the human-generated gold standard. However, the ultimate goal is the ability to use unedited autosegmented OARs in treatment planning, while maintaining the plan quality. We tested this approach with head and neck (HN) OARs generated by a prototype deep-learning (DL) model on patients previously treated for oropharyngeal and laryngeal cancer. Forty patients were selected, with all structures delineated by an experienced physician. For each patient, a set of 13 OARs were generated by the DL model. Each patient was re-planned based on original targets and unedited DL-produced OARs. The new dose distributions were then applied back to the manually delineated structures. The target coverage was evaluated with inhomogeneity index (II) and the relative volume of regret. For the OARs, Dice similarity coefficient (DSC) of areas under the DVH curves, individual DVH objectives, and composite continuous plan quality metric (PQM) were compared. The nearly identical primary target coverage for the original and re-generated plans was achieved, with the same II and relative volume of regret values. The average DSC of the areas under the corresponding pairs of DVH curves was 0.97 ± 0.06. The number of critical DVH points which met the clinical objectives with the dose optimized on autosegmented structures but failed when evaluated on the manual ones was 5 of 896 (0.6%). The average OAR PQM score with the re-planned dose distributions was essentially the same when evaluated either on the autosegmented or manual OARs. Thus, rigorous HN treatment planning is possible with OARs segmented by a prototype DL algorithm with minimal, if any, manual editing.


Assuntos
Aprendizado Profundo , Neoplasias Laríngeas , Radioterapia de Intensidade Modulada , Humanos , Neoplasias Laríngeas/etiologia , Planejamento da Radioterapia Assistida por Computador , Órgãos em Risco , Radioterapia de Intensidade Modulada/efeitos adversos , Dosagem Radioterapêutica
13.
JAMA Cardiol ; 9(2): 105-113, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38055237

RESUMO

Importance: Readmissions after an index heart failure (HF) hospitalization are a major contemporary health care problem. Objective: To evaluate the feasibility and efficacy of an intensive telemonitoring strategy in the vulnerable period after an HF hospitalization. Design, Setting, and Participants: This randomized clinical trial was conducted in 30 HF clinics in Brazil. Patients with left ventricular ejection fraction less than 40% and access to mobile phones were enrolled up to 30 days after an HF admission. Data were collected from July 2019 to July 2022. Intervention: Participants were randomly assigned to a telemonitoring strategy or standard care. The telemonitoring group received 4 daily short message service text messages to optimize self-care, active engagement, and early intervention. Red flags based on feedback messages triggered automatic diuretic adjustment and/or a telephone call from the health care team. Main Outcomes and Measures: The primary end point was change in N-terminal pro-brain natriuretic peptide (NT-proBNP) from baseline to 180 days. A hierarchical win-ratio analysis incorporating blindly adjudicated clinical events (cardiovascular deaths and HF hospitalization) and variation in NT-proBNP was also performed. Results: Of 699 included patients, 460 (65.8%) were male, and the mean (SD) age was 61.2 (14.5) years. A total of 352 patients were randomly assigned to the telemonitoring strategy and 347 to standard care. Satisfaction with the telemonitoring strategy was excellent (net promoting score at 180 days, 78.5). HF self-care increased significantly in the telemonitoring group compared with the standard care group (score difference at 30 days, -2.21; 95% CI, -3.67 to -0.74; P = .001; score difference at 180 days, -2.08; 95% CI, -3.59 to -0.57; P = .004). Variation of NT-proBNP was similar in the telemonitoring group compared with the standard care group (telemonitoring: baseline, 2593 pg/mL; 95% CI, 2314-2923; 180 days, 1313 pg/mL; 95% CI, 1117-1543; standard care: baseline, 2396 pg/mL; 95% CI, 2122-2721; 180 days, 1319 pg/mL; 95% CI, 1114-1564; ratio of change, 0.92; 95% CI, 0.77-1.11; P = .39). Hierarchical analysis of the composite outcome demonstrated a similar number of wins in both groups (telemonitoring, 49 883 of 122 144 comparisons [40.8%]; standard care, 48 034 of 122 144 comparisons [39.3%]; win ratio, 1.04; 95% CI, 0.86-1.26). Conclusions and Relevance: An intensive telemonitoring strategy applied in the vulnerable period after an HF admission was feasible, well-accepted, and increased scores of HF self-care but did not translate to reductions in NT-proBNP levels nor improvement in a composite hierarchical clinical outcome. Trial Registration: ClinicalTrials.gov Identifier: NCT04062461.


Assuntos
Insuficiência Cardíaca , Envio de Mensagens de Texto , Humanos , Masculino , Pessoa de Meia-Idade , Feminino , Volume Sistólico , Função Ventricular Esquerda , Insuficiência Cardíaca/terapia , Hospitalização
14.
JAMA cardiol. (Online) ; 9(2): 105-113, 2024.
Artigo em Inglês | CONASS, Sec. Est. Saúde SP, SESSP-IDPCPROD, Sec. Est. Saúde SP | ID: biblio-1531070

RESUMO

IMPORTANCE: Readmissions after an index heart failure (HF) hospitalization are a major contemporary health care problem. OBJECTIVE: To evaluate the feasibility and efficacy of an intensive telemonitoring strategy in the vulnerable period after an HF hospitalization. DESIGN, SETTING, AND PARTICIPANTS: This randomized clinical trial was conducted in 30 HF clinics in Brazil. Patients with left ventricular ejection fraction less than 40% and access to mobile phones were enrolled up to 30 days after an HF admission. Data were collected from July 2019 to July 2022. INTERVENTION: Participants were randomly assigned to a telemonitoring strategy or standard care. The telemonitoring group received 4 daily short message service text messages to optimize self-care, active engagement, and early intervention. Red flags based on feedback messages triggered automatic diuretic adjustment and/or a telephone call from the health care team. MAIN OUTCOMES AND MEASURES: The primary end point was change in N-terminal pro-brain natriuretic peptide (NT-proBNP) from baseline to 180 days. A hierarchical win-ratio analysis incorporating blindly adjudicated clinical events (cardiovascular deaths and HF hospitalization) and variation in NT-proBNP was also performed. RESULTS: Of 699 included patients, 460 (65.8%) were male, and the mean (SD) age was 61.2 (14.5) years. A total of 352 patients were randomly assigned to the telemonitoring strategy and 347 to standard care. Satisfaction with the telemonitoring strategy was excellent (net promoting score at 180 days, 78.5). HF self-care increased significantly in the telemonitoring group compared with the standard care group (score difference at 30 days, -2.21; 95% CI, -3.67 to -0.74; P = .001; score difference at 180 days, -2.08; 95% CI, -3.59 to -0.57; P = .004). Variation of NT-proBNP was similar in the telemonitoring group compared with the standard care group (telemonitoring: baseline, 2593 pg/mL; 95% CI, 2314-2923; 180 days, 1313 pg/mL; 95% CI, 1117-1543; standard care: baseline, 2396 pg/mL; 95% CI, 2122-2721; 180 days, 1319 pg/mL; 95% CI, 1114-1564; ratio of change, 0.92; 95% CI, 0.77-1.11; P = .39). Hierarchical analysis of the composite outcome demonstrated a similar number of wins in both groups (telemonitoring, 49 883 of 122 144 comparisons [40.8%]; standard care, 48 034 of 122 144 comparisons [39.3%]; win ratio, 1.04; 95% CI, 0.86-1.26). CONCLUSIONS and relevance: An intensive telemonitoring strategy applied in the vulnerable period after an HF admission was feasible, well-accepted, and increased scores of HF self-care but did not translate to reductions in NT-proBNP levels nor improvement in a composite hierarchical clinical outcome.


Assuntos
Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Envio de Mensagens de Texto , Insuficiência Cardíaca/terapia , Volume Sistólico , Função Ventricular Esquerda
15.
Phys Imaging Radiat Oncol ; 28: 100505, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38045642

RESUMO

Background and purpose: Diffusion weighted imaging (DWI) allows for the interrogation of tissue cellularity, which is a surrogate for cellular proliferation. Previous attempts to incorporate DWI into the workflow of a 0.35 T MR-linac (MRL) have lacked quantitative accuracy. In this study, accuracy, repeatability, and geometric precision of apparent diffusion coefficient (ADC) maps produced using an echo planar imaging (EPI)-based DWI protocol on the MRL system is illustrated, and in vivo potential for longitudinal patient imaging is demonstrated. Materials and methods: Accuracy and repeatability were assessed by measuring ADC values in a diffusion phantom at three timepoints and comparing to reference ADC values. System-dependent geometric distortion was quantified by measuring the distance between 93 pairs of phantom features on ADC maps acquired on a 0.35 T MRL and a 3.0 T diagnostic scanner and comparing to spatially precise CT images. Additionally, for five sarcoma patients receiving radiotherapy on the MRL, same-day in vivo ADC maps were acquired on both systems, one of which at multiple timepoints. Results: Phantom ADC quantification was accurate on the 0.35 T MRL with significant discrepancies only seen at high ADC. Average geometric distortions were 0.35 (±0.02) mm and 0.85 (±0.02) mm in the central slice and 0.66 (±0.04) mm and 2.14 (±0.07) mm at 5.4 cm off-center for the MRL and diagnostic system, respectively. In the sarcoma patients, a mean pretreatment ADC of 910x10-6 (±100x10-6) mm2/s was measured on the MRL. Conclusions: The acquisition of accurate, repeatable, and geometrically precise ADC maps is possible at 0.35 T with an EPI approach.

16.
An Acad Bras Cienc ; 95(4): e20191162, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38088696

RESUMO

Male broiler chickens (384), Cobb 500, were housed in metabolic cages to assess the efficacy of phytase in diets with low and high phytate-phosphorus on the performance, bone physical characteristics, tissue and serum mineral deposits. Birds were distributed in four treatments with a 2 x 2 factorial arrangement in a completely randomized block design. Experimental diets based on maize-soybean meal were T1 - diet low phytate-phosphorus; T2 - diet low phytate-phosphorus and phytase (500 FTU/kg); T3 - diet high phytate-phosphorus; T4 - diet high phytate-phosphorus and phytase (500 FTU/kg). Feed intake, body weight, weight gain and feed conversion ratio were assessed. Two left tibias per experimental unit were analyzed for physical characteristics and mineral concentration; a section of skinless breast muscle and blood were collected to measure the concentration of calcium, phosphorus and sodium. Results showed interaction between bone stiffness and serum calcium. The inclusion of phytase in diets with low and high phytate-phosphorus did not alter performance, bone resistance and flexibility, mineral deposits in the tibia and breast muscle, but increased bone stiffness after 22 days of age. It also provided a higher serum calcium rate in broilers fed diets with low phytate-phosphorus up to 32 days of age.


Assuntos
6-Fitase , Fósforo , Animais , Masculino , 6-Fitase/metabolismo , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Cálcio/metabolismo , Galinhas/fisiologia , Dieta/veterinária , Suplementos Nutricionais , Minerais , Fósforo/metabolismo , Ácido Fítico
17.
Phys Rev E ; 108(5-1): 054223, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38115440

RESUMO

We investigate the extent to which the probabilistic properties of chaotic scattering systems with dissipation can be understood from the properties of the dissipation-free system. For large energies, a fully chaotic scattering leads to an exponential decay of the survival probability P(t)∼e^{-κt}, with an escape rate κ that decreases with energy. Dissipation leads to the appearance of different finite-time regimes in P(t). We show how these different regimes can be understood for small dissipations and long times from the (effective) escape rate κ (including the nonhyperbolic regime) of the conservative system, until the energy reaches a critical value at which no escape is possible. More generally, we argue that for small dissipation and long times the surviving trajectories in the dissipative system are distributed according to the conditionally invariant measure of the conservative system at the corresponding energy. Quantitative predictions of our general theory are compared with numerical simulations in the Hénon-Heiles model.

18.
Invest Ophthalmol Vis Sci ; 64(15): 27, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-38117242

RESUMO

Purpose: Although there have been improvements in the management of metastatic retinoblastoma, most patients do not survive, and all patients suffer from multiple short- and long-term treatment toxicities. Reliable and informative models to assist clinicians are needed. Thus we developed and comprehensively characterized a novel preclinical platform of primary cell cultures and xenograft models of metastatic retinoblastoma to provide insights into the molecular biology underlying metastases and to perform drug screening for the identification of hit candidates with the highest potential for clinical translation. Methods: Orbital tumor, bone marrow, cerebrospinal fluid, and lymph node tumor infiltration specimens were obtained from seven patients with metastatic retinoblastoma at diagnosis, disease progression, or relapse. Tumor specimens were engrafted in immunodeficient animals, and primary cell lines were established. Genomic, immunohistochemical/immunocytochemical, and pharmacological analysis were performed. Results: We successfully established five primary cell lines: two derived from leptomeningeal, two from orbital, and one from lymph node tumor dissemination. After the intravitreal or intraventricular inoculation of these cells, we established cell-derived xenograft models. Both primary cell lines and xenografts accurately retained the histological and genomic features of the tumors from which they were derived and faithfully recapitulated the dissemination patterns and pharmacological sensitivity observed in the matched patients. Conclusions: Ours is an innovative and thoroughly characterized preclinical platform of metastatic retinoblastoma developed for the understanding of tumor biology of this highly aggressive tumor and has the potential to identify drug candidates to treat patients who currently lack effective treatment options.


Assuntos
Neoplasias da Retina , Retinoblastoma , Animais , Humanos , Retinoblastoma/tratamento farmacológico , Retinoblastoma/genética , Recidiva Local de Neoplasia , Linhagem Celular , Modelos Animais de Doenças , Neoplasias da Retina/tratamento farmacológico , Neoplasias da Retina/genética
19.
PNAS Nexus ; 2(11): pgad364, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38034095

RESUMO

Decomposing a graph into groups of nodes that share similar connectivity properties is essential to understand the organization and function of complex networks. Previous works have focused on groups with specific relationships between group members, such as assortative communities or core-periphery structures, developing computational methods to find these mesoscale structures within a network. Here, we go beyond these two traditional cases and introduce a methodology that is able to identify and systematically classify all possible community types in directed multi graphs, based on the pairwise relationship between groups. We apply our approach to 53 different networks and find that assortative communities are the most common structures, but that previously unexplored types appear in almost every network. A particularly prevalent new type of relationship, which we call a source-basin structure, has information flowing from a sparsely connected group of nodes (source) to a densely connected group (basin). We look in detail at two online social networks-a new network of Twitter users and a well-studied network of political blogs-and find that source-basin structures play an important role in both of them. This confirms not only the widespread appearance of nonassortative structures but also the potential of hitherto unidentified relationships to explain the organization of complex networks.

20.
J Clin Med ; 12(22)2023 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-38002622

RESUMO

OBJECTIVE: Modifications in the severity and clinical expression of Behçet's disease (BD) have been described in some areas that are considered endemic for the disease. This study aims to evaluate the chronological changes in epidemiology and clinical characteristics of BD patients in a referral center in Brazil, which is considered a non-endemic area for the disease. METHODS: A descriptive and cross-sectional study involving BD patients divided into two groups: group 1 patients were diagnosed and followed between 1988 and 2010, and group 2 were diagnosed and followed between 2011 and 2022. RESULTS: No significant differences were found regarding gender and age at onset of symptoms between groups. We found a significant decrease in the frequency of bilateral ocular involvement, posterior uveitis, and retinal vasculitis. CONCLUSION: The demographic dates of this group of Brazilian BD patients remained similar over the last decade. Our study supports the notion that BD is becoming lighter in some regions. BD is a severe blinding disorder, and we found a lower frequency of ocular involvement over time. These findings may be attributed to a higher level of education of patients and a growing awareness of the disease. Newer immunomodulating and biologic agents may offer an improved prognosis in patients with BD with severe manifestations.

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