IF - Artigos publicados em periódicos

URI Permanente para esta coleçãohttp://200.137.215.59//handle/ri/1359

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Termômetro digital para dispositivos de eletroformação de vesículas unilamelares gigantes
(2026) Santos Júnior, Juracy Leandro dos; Mendanha Neto, Sebastião Antônio; Santos, Marcus Carrião dos; Vieira, Sílvio Leão
This work describes the development of a multichannel digital thermometer to validate the temperature control of giant unilamellar vesicle (GUVs) electroformation equipment. The prototype presented was built with cheap and conventional resources, such as elements and circuits from the Arduino open-source platform and negative temperature coefficient (NTC) thermistors, resulting in equipment with good precision, low production cost and easy maintenance. The device allows temperature measurement in four channels simultaneously and records the values on the computer for temporal evaluation. This equipment was essential in the process of creating a GUV electroforming device discussed elsewhere, but there are several possibilities for application in the research and development of other temperature-dependent technologies. In particular, the device allowed the development of the GUV electroformation protocol by identifying the delay process caused by positioning the thermometer outside the studied sample.
Medições acústico-elásticas da dose absorvida emdosímetro de gel polimérico como material simulador de tecido
(2026) Teófilo, Ana Clara Oliveira de Queiroz; Dias, Pedro Henrique Coelho; Vieira, Sílvio Leão
Accurate absorbed dose dosimetry is a key factor for the effectiveness and safety of radiotherapy treatments, particularly when three-dimensional dose verification is required. In this context, polymer gel dosimeters stand out for their ability to record volumetric dose distributions, traditionally read using magnetic resonance imaging, a high-cost technique with limited clinical availability. This study investigates the applicability of an ultrasonic system as an alternative method for reading MAGIC-F polymer gel dosimeters used in radiotherapy. Initially, the system was calibrated using homogeneous gelatin-based samples with different concentrations, evaluating the response of ultrasonic velocity, attenuation coefficient, and elastic moduli. Subsequently, the methodology was applied to MAGIC-F gel samples irradiated with absorbed doses ranging from 0 to 40 Gy. Longitudinal ultrasonic velocity and attenuation coefficient were experimentally determined using the transmission–reception technique, while elasticmoduli were estimated based on empirical relations supported by the literature. The results indicate an approximately linear attenuation behavior between 0 and 30 Gy, with a more pronounced variation at higher doses, suggesting distinct material response regimes. A systematic increase in mechanical stiffness with dose was also observed, as evidenced by the increase in Young’s modulus. These findings demonstrate the potential of ultrasound as a complementary tool for three-dimensional absorbed dose readout in polymer gel dosimetry.
Otimização do fluxo de atendimento de pacientes de um serviço de radioterapia utilizando o ciclo PDCA
(2025) Santos, Rogério Sanches; Ribeiro, Carlos Eduardo; Oliveira, Carlos Eduardo Gonçalves de; Itikawa, Emerson Nobuyuki
This study explored the application of the PDCA Cycle (Plan, Do, Check, Act) to optimize the patient care workflow in a radiotherapy service, focusing on efficient scheduling and execution of sessions on linear accelerators. Prior to the study, the servicefaced workload overload issues with significant delays, especially in the afternoon and evening periods. The methodology included the standardization of routines, definition of performance indicators, and restructuring of the schedulebased on the actual capacity of the equipment, adjusting the average times by type of treatment. In the implementation of the PDCA Cycle, quality management tools were used, i.e., brainstorming, 5 Whys, Ishikawa diagram, and control charts. The results showed a significant reduction (p<0.05) in delays without compromising service capacity. The reorganization of slot time enabled an optimal distribution of workload with more efficient use of resources, resulting in punctual sessions and shorter waiting times. Patient satisfaction analysis after the intervention revealed a reduction in complaints related to delays and an improved perception of efficiency in care. The application of the PDCA Cycle proved effective in optimizing the care workflow through schedule and slot timeadjustments. The continuous adoption of the PDCA Cycle has shown to be a resilient and adaptable strategy, promoting quality, efficiency, and safety in radiotherapy care.
Image quality and dose reduction in cardiac interventional procedures: application of an optimization strategy with typical dose value analysis
(2025) Assunção, Murilo Felisberto Morais de; Silva, Jonas Oliveira da; Silva, Guilherme Custódio Cândido; Itikawa, Emerson Nobuyuki
This study aimed to evaluate the impact of dose-optimization strategies on radiation exposure during cardiac catheterization and angioplastyprocedures. The investigation was carried out at a high-complexity referral center using retrospective data, clinical-protocol adjustments, and image-quality assessments with dedicated simulators. Implemented measures included reducing the cine dose per frame and enabling post-processing filters, resulting in reductions of up to 39% in reference-point kermaand 25% in noise intensity under low-dose conditions. In total, 714 procedures performed over five semesters were analyzed. Diagnostic reference levels (DRLs) were determined and compared with data from national and international literature. A statistically significant reduction in DAP(16.3%) and Kₐ,r(12.8%) was observed for catheterization procedures (p<0.05). Although angioplasty procedures showed a similar trend, case variability limited statistical significance. The results demonstrate the effectiveness of technical interventions andcontinuous monitoring in lowering exposure levels,without compromising diagnostic image quality.Keywords:reference level;digital fluoroscopy; dose; image quality; optimization.
Avaliação do impacto do retreino periódico na predição de não-comparecimentos de pacientes em consultas médicas utilizando Balanced Random Forest
(2025) Oliveira, Carlos Eduardo Gonçalves de; Teixeira, Ana Beatriz Marinho de Jesus; Diaz Salazar, Aldo André; Oliveira, Mateus Simão; Itikawa, Emerson Nobuyuki
Breast tumor segmentation in ultrasound images: comparing U-net and U-net + +
(2025) Oliveira, Carlos Eduardo Gonçalves de; Vieira, Sílvio Leão; Paranaiba, Caio Felipe Brito; Itikawa, Emerson Nobuyuki
Purpose To compare the performance of U-net and U-net + + neural networks for the segmentation of breast tumors in ultrasound (US) images, focusing on a robust and easily reproducible methodology. Methods The Breast Ultrasound Images Dataset (BUSI), comprising 780 images, was used with 60% separated for training, 20% for validation, and 20% for testing. Data augmentation (DA) techniques were applied to improve model generalization, and an Intersection over Union (IoU)–based loss function was utilized. Both models were trained for 1000 epochs. The Dice coefficient was the primary metric for evaluating segmentation performance, while accuracy, precision, recall, and F1-score were used for assessing the model’s ability to detect tumors. Results U-net + + demonstrated superior performance, achieving a maximum average Dice score of 75.71% on validation data, compared to 75.17% for U-net. On test data, U-net + + obtained a median Dice score of 88.60% with an IQR of 30.53%. In the classification task, U-net + + achieved an accuracy of 90% and a F1-score of 94% for tumor detection. Conclusions U-net + + outperforms the base U-net in segmentation task on breast US images. While the results are promising, further enhancements could be achieved with larger datasets or integration with more complex techniques. It is encouraged a more detailed hyperparameter tuning, as it could significantly improve the results.
Predicting patient no-shows in magnetic resonance imaging appointments using interpretable machine learning
(2026) Oliveira, Carlos Eduardo Gonçalves de; Teixeira, Ana Beatriz Marinho de Jesus; Oliveira, Mateus Simão; Itikawa, Emerson Nobuyuki
Missed appointments, or no-shows, in Magnetic Resonance Imaging (MRI) procedures lead to underutilised resources and scheduling inefficiencies in healthcare. This study proposes an interpretable machine learning framework to predict patient no-shows using real-world data from a brazilian diagnostic imaging clinic (n = 28991; no-show rate = 8.2%). We evaluated Logistic Regression, Multilayer Perceptron, XGBoost, CatBoost, and LightGBM, incorporating both patient-level and clinic-level features, including historical demand and no-show trends. Time-split cross-validation was used for hyperparameter tuning, selecting models based on AUC-PR, and for adjusting the probability threshold using the 𝐹𝛽-score with 𝛽 = 1.5. The LightGBM model was selected and achieved an AUC-PR of 0.2203 and AUC-ROC of 0.6559 on test data, with Precision = 19.68%, Sensitivity = 39.63%, 𝐹1-score = 26.30% and overall accuracy = 82.37%. SHAP values were used to interpret feature contributions, revealing that variables such as patient age, sex, distance to clinic, healthcare plan, waiting time, and no-show history were most influential. This framework enables data-driven overbooking strategies and personalised reminders, aligning with operational goals and minimising resource waste. Our approach demonstrates that interpretable models can support clinical decision-making in realistic environments, with potential extensions to other healthcare domains.
Diffractive Lugiato-Lefever equation driven by a double tightly focused pump
(2025) Santos, Mateus Calixto Pereira dos; Kumar, Shatrughna; Cardoso, Wesley Bueno; Malomed, Boris A.
We introduce a model of an optical cavity based on the one-dimensional Lugiato-Lefever (LL) equation, which includes the pump represented by a symmetric pair of tightly localized “hot spots” (HSs) with phase shift 𝜒 between them, and self-focusing or defocusing cubic nonlinearity. Families of bound states, pinned to the double HS, are found in the system's parameter space. They feature the effect of the symmetry breaking (SB) between peaks pinned to individual HSs, provided that the phase shift takes values 0<𝜒<𝜋, and the LL equation includes the loss term. The SB, which is explained analytically, takes place in the full LL model and its linearized version alike. The same phenomenology is also explored in the framework of the LL equation with the double HS and quintic self-focusing. In that case, there are stable symmetric and asymmetric bound states, in spite of the presence of the background instability driven by the critical collapse.
Spontaneous symmetry breaking induced by nonlinear interaction in a coupler supported by fractional diffraction
(2025) Santos, Mateus Calixto Pereira dos; Cardoso, Wesley Bueno
In this paper we introduce a one-dimensional model of coupled fractional nonlinear Schrödinger equations with a double-well potential applied to one component. This study examines ground state (GS) solitons, observing spontaneous symmetry breaking (SSB) in both the actuated field and the partner component due to nonlinear coupling. Numerical simulations reveal symmetric and asymmetric profiles arising from a slightly asymmetric initial condition. Asymmetry is influenced by nonlinearities, potential depth, and coupling strength, with self-focusing systems favoring greater asymmetry. Fractional diffraction affects the amplitude and localization of symmetric profiles and the stability of asymmetric ones. We identify critical Lévy index values for generating coupled GS solitons. Stability analysis of unstable, centrally asymmetric GS solitons demonstrates oscillatory dynamics, providing new insights into SSB in fractional systems and half-trapped solitons.
Inducing localized solutions via interaction in a self-defocusing system with localized pumping
(2025) Cardoso, Wesley Bueno; Santos, Mateus Calixto Pereira dos
We investigate the emergence of induced localized coupled modes in passive cavities with both loss and gain. Our model is based on linearly coupled Lugiato-Lefever equations, where a Gaussian pump beam is applied to only one mode. Through numerical simulations, we demonstrate that self-defocusing systems are capable of supporting the formation of localized stationary modes in the partner field. The characteristics of these induced modes are determined by key parameters, including coupling strength, cavity decay rate, detuning effects, and the pump beam's intensity and width.
Alternative split-step method for solving linearly coupled nonlinear Schrödinger equations
(2025) Cardoso, Wesley Bueno
In this paper we introduce an alternative method for solving linearly coupled nonlinear Schrödinger equations by using a split-step approach. This methodology involves approximating the nonlinear part of the evolution operator, allowing it to be solved exactly, which significantly enhances computational efficiency. The dispersive component is addressed using a spectral method, ensuring accuracy in the treatment of linear terms. As a reference, we compare our results with those obtained using the Runge-Kutta method implemented using a pseudo-spectral technique. Our findings indicate that the proposed split-step method achieves precision comparable to that of the Runge-Kutta method while nearly doubling computational efficiency. Numerical simulations include the evolution of a single soliton in each field and a collision between two solitons, demonstrating the robustness and effectiveness of our approach.
Development and spectroscopy study of YPO4:Tm3+ nanopowders
(2025) Torquato, Francisco Alisson da Silva; Santana, Ricardo Costa de; Maia, Lauro June Queiroz
The Y1-xTmxPO4 nanopowders were successfully synthesized via the coprecipitation method assisted by slow evaporation under basic conditions (pH = 10), yielding particles with an average length of about 26 nm ± 8 nm observed by Transmission Electron Microscopy images. The diffuse reflectance spectra (DRS) show higher reflectance of powdered samples in the visible range, and optical bandgaps (Eg) values were obtained using the Kubelka-Munk approach, which ranged from 4.5 to 4.7 eV, indicating an insulator nature. The powders displayed remarkably intense blue emission centred at 452 nm, originating from the 1D2 → 3H6 transition under 361.5 nm excitation. This emission was accompanied by a residual contribution from a near-infrared emission band at approximately 783 nm, which was attributed to the 1G4 → 3H5 and 3H4 → 3H6 transitions due to residual multiphonon decay and cross-relaxation mechanisms, respectively. The lifetimes of the 1D2 state range from 42 to 35 µs, displaying monoexponential behaviour as the concentration rises from 0.25 % mol to 2 % mol. The dipole-dipole interaction between ions is confirmed for blue emission using the Dexter model, which has a critical distance of ∼ 24 Å. The same behaviour is also observed for the lifetimes from the 1G4 state, decreasing from 422 µs (0.25 mol. %) to 170 µs (2 mol. %), with a bi-exponential behaviour due to the more effective cross-relaxation mechanisms. The relative changes between 1D2 and 1G4 energy levels allow for tuning the emission colour from blue to cyan by adjusting the delay time. Additionally, the CIE chromaticity coordinates of steady-state PL spectra indicate that the samples have a colour purity of above 93 % for x > 0.01 in the deep blue region, indicating the Y1-xTmxPO4 nanopowders as a versatile blue to cyan emitter component for W-LED applications.
Improvement of electronic structure calculations for the interpretation of the emission spectrum for NdIII complexes
(2025) Gil Sánchez, Yolimar; Maldonado, María José; Santana, Ricardo Costa de; Vega, Andrés; Fuentealba, Pablo; Aravena, Daniel
A protocol to correct ab initio calculated luminescence spectra of NdIII complexes is proposed. The emission spectrum of [NdIII(bipy)(tta)3] was measured to calibrate the optimal correction for the Racah parameters on top of a CASSCF calculation to attain the best energetic placement of the 4F3/2 → 4I13/2−9/2 emission lines. As interelectronic repulsion is the most important source of error in this calculation, this straightforward correction results in an accurate placement of transitions, allowing the assignment of a complex spectral shape in terms of its underlying transitions. Finally, the correction derived for [NdIII(bipy)(tta)3] was directly applied to a different NdIII complex, demonstrating the broad use of this approach.
Trichromatic color tuning strategy for emission of heterometallic EuIII/TbIII coordination polymers with triazolyl-substituted 4-methyl-phenoxo ligand
(2025) Pérez Obando, Juliana; Manzur Saffie, Jorge Alberto; Fuentealba, Pablo; Morales Alfaro, Jeannette; Vega, Andrés; Santana, Ricardo Costa de; Carneiro Neto, Albano Neto; Spodine, Evgenia
This study presents the microwave-assisted synthesis and characterization of a series of heterometallic coordination polymers (HMCPs) with a 4-methyl-2,6-di[(1H-1,2,4-triazol-1-yl)]phenoxo ligand with varying EuIII/TbIII ratios. Single crystal X-ray diffraction reveals a double-chain structure bridged by triazolyl groups. Powder X-ray diffraction confirms the isostructural nature of the synthesized HMCPs. The photophysical properties depend on lanthanide ion concentration and excitation wavelength, leading to a color shift from green to blue as the proportion of TbIII decreases and EuIII increases. White light generation is achieved in the 8/2 EuIII/TbIII HMCP (CIE: 0.293, 0.326) under 335 nm excitation. The study suggests energy transfer from TbIII to EuIII, but both experimental and theoretical calculations indicate that this transfer is orders of magnitude lower than the sensitization through ligand states.
Anti-thermal quenching in NdIII molecular near-infrared thermometers operating at physiological temperatures
(2025) Maldonado, María José; Farías Carreño, Patricia; Gil Sánchez, Yolimar; Vega, Andrés; Santana, Ricardo Costa de; Aravena, Daniel; Brites, Carlos D. S.; Carlos, Luis Dias; Carneiro Neto, Albano Neto; Vetrone, Fiorenzo
Examples of molecular complexes acting as thermometers operating at room temperature in near infrared region are scarce, therefore this work showcases the anti-thermal quenching effect on neodymium(III) molecular thermometers working in biological windows within the physiological temperature range. A mononuclear complex, [Nd(L)(NO3)3] (1Nd), where L is a macrocyclic ligand, was synthesized and used as a precursor to develop two novel species: a dinuclear, [(Nd(L)(NO3))2(µ-BDC)](NO3)2·H2O (2Nd), linked by 1,4-benzenedicarboxylate (BDC), and a hexameric, [(Nd(L))(µ-BTC)(H2O)]6·35H2O (6Nd), linked with 1,3,5-benzenetricarboxylate (BTC). Thermometric properties were studied in the physiological temperature range (292-332 K), utilizing 804 nm laser excitation (first biological window) and monitoring emissions in the second biological window (908, 1065, and 1340 nm) associated with the 4F3/2 → 4I9/2, 4I11/2, 4I13/2 transitions, respectively. Among the complexes, the hexamer 6Nd exhibited exceptional performance, with Sr of 2.4%K−1 at 293 K, when luminescence intensity ratio (LIR) of two Stark components of the 4F3/2 → 4I11/2 emission was used, positioning it as a high-performance NdIII-based thermometer. All complexes displayed anti-thermal quenching behavior, surpassing the current molecular-based thermometers in the near-infrared region. Theoretical calculations using complete active space self consistent field (CASSCF) and Boltzmann population models between Kramers doublets of the 4F3/2 level were performed to rationalize the anti-thermal behavior.
Measurements of pion and muon nuclear capture at rest on argon in the LArIAT experiment
(2025) Hernandez Morquecho, Miguel Angel; Acciarri, Roberto; Asaadi, Jonathan Abraham; Backfish, Michael; Badgett, William Farris; Basque, Vincent Marc; Blaszczyk, F. D. M.; Foreman, William; Gomes, Ricardo Avelino; Gramellini, Elena
We report the measurement of the final-state products of negative pion and muon nuclear capture at rest on argon by the LArIAT experiment at the Fermilab Test Beam Facility. We measure a population of isolated MeV-scale energy depositions, or blips, in 296 LArIAT events containing tracks from stopping low-momentum pions and muons. The average numbers of visible blips are measured to be 0.74 ±0.19 and 1.86 ±0.17 near muon and pion track endpoints, respectively. The 3.6⁢𝜎 statistically significant difference in blip content between muons and pions provides the first demonstration of a new method of pion-muon discrimination in neutrino liquid argon time projection chamber experiments. LArIAT Monte Carlo simulations predict substantially higher average blip counts for negative muon (1.22 ±0.08) and pion (2.34 ±0.09) nuclear captures. We attribute this difference to geant4’s inaccurate simulation of the nuclear capture process.
The track-length extension fitting algorithm for energy measurement of interacting particles in liquid argon TPCs and its performance with ProtoDUNE-SP data
(2025) Abud, Adam Abed; Abi, Babak; Acciarri, Roberto; Acero Ortega, Mario Andrés; Adames, Márcio Rostirolla; Adamov, George; Adamowski, Mark; Adams, David; Adinolfi, Marco; Adriano, Cris; Gomes, Ricardo Avelino
This paper introduces a novel track-length extension fitting algorithm for measuring the kinetic energies of inelastically interacting particles in liquid argon time projection chambers (LArTPCs). The algorithm finds the most probable offset in track length for a track-like object by comparing the measured ionization density as a function of position with a theoretical prediction of the energy loss as a function of the energy, including models of electron recombination and detector response. The algorithm can be used to measure the energies of particles that interact before they stop, such as charged pions that are absorbed by argon nuclei. The algorithm's energy measurement resolutions and fractional biases are presented as functions of particle kinetic energy and number of track hits using samples of stopping secondary charged pions in data collected by the ProtoDUNE-SP detector, and also in a detailed simulation. Additional studies describe the impact of the dE/dx model on energy measurement performance. The method described in this paper to characterize the energy measurement performance can be repeated in any LArTPC experiment using stopping secondary charged pions.
Neutrino interaction vertex reconstruction in DUNE with Pandora deep learning
(2025) Abud, Adam Abed; Acciarri, Roberto; Acero Ortega, Mario Andrés; Adames, Márcio Rostirolla; Adamov, George; Adamowski, Mark; Adams, David; Adinolfi, Marco; Adriano, Cris; Aduszkiewicz, Antoni; Gomes, Ricardo Avelino
The Pandora Software Development Kit and algorithm libraries perform reconstruction of neutrino interactions in liquid argon time projection chamber detectors. Pandora is the primary event reconstruction software used at the Deep Underground Neutrino Experiment, which will operate four large-scale liquid argon time projection chambers at the far detector site in South Dakota, producing high-resolution images of charged particles emerging from neutrino interactions. While these high-resolution images provide excellent opportunities for physics, the complex topologies require sophisticated pattern recognition capabilities to interpret signals from the detectors as physically meaningful objects that form the inputs to physics analyses. A critical component is the identification of the neutrino interaction vertex. Subsequent reconstruction algorithms use this location to identify the individual primary particles and ensure they each result in a separate reconstructed particle. A new vertex-finding procedure described in this article integrates a U-ResNet neural network performing hit-level classification into the multi-algorithm approach used by Pandora to identify the neutrino interaction vertex. The machine learning solution is seamlessly integrated into a chain of pattern-recognition algorithms. The technique substantially outperforms the previous BDT-based solution, with a more than 20% increase in the efficiency of sub-1 cm vertex reconstruction across all neutrino flavours.
First observation of antiproton annihilation at rest on argon in the LArIAT experiment
(2025) Basque, Vincent Marc; Acciarri, Roberto; Asaadi, Jonathan Abraham; Backfish, Michael; Badgett, William Farris; Cavanna, F.; Flanagan, W.; Foreman, William; Gomes, Ricardo Avelino
We report the first observation and measurement of antiproton annihilation at rest on argon track and shower multiplicities and particle identification conducted with the LArIAT experiment. Stopping antiprotons from the Fermilab Test Beam Facility’s charged particle test beam are identified using beamline instrumentation and LArIAT’s liquid argon time projection chamber (LArTPC). The charged particle multiplicity from the annihilation vertex is manually evaluated via hand scanning, yielding a mean of 3.2 ±0.4 tracks and a standard deviation of 1.3 tracks, consistent with a semiautomated reconstruction resulting in 2.8 ±0.4 tracks and a standard deviation of 1.2 tracks. Both methods are consistent with Monte Carlo simulations within statistical uncertainty. The shower multiplicities and particle identification for outgoing tracks are also consistent with geant4 model predictions. These results, obtained from a low-statistics sample, provide a foundation for higher-statistics studies in larger LArTPCs, which could refine modeling of intranuclear annihilation on argon and inform scenarios such as neutron-antineutron oscillations.
Surface palladium nanoparticles in ionic liquids modified with phosphorus ligands for enhanced catalytic semi-hydrogenation
(2025) Qadir, Muhammad Irfan; Chacon Rosales, Gustavo Javier; Ebersol, Camila Porto; Abarca Anjari, Gabriel Nelson; Matias, Pedro Henrique Ferreira; Oliveira, Heibbe Cristhian Benedito de; Pontes, Renato Borges; Stieler, Rafael; Dupont, Jairton
Thermodynamic stability of nanoparticles necessitates the use of stabilizing agents to provide steric and electronic protection. However, their activity and selectivity remain suboptimal under moderate reaction conditions. In this study, we present high-performance Pd nanoparticles featuring a distinctive Pd–phosphine surface, akin to a “quasi nano-frustrated Lewis pair” architecture. In this system, electron donation from ionophilic phosphine species enhances the electron density of the Pd nanoparticles, contributing to their improved performance. Solid-state NMR and XPS analyses disclose the strong coordination of phosphine species on the Pd NPs. DFT calculations reveal the geometry and conformations of the coordinated phosphine, showing that one of the phenyl rings aligns nearly parallel to the nanoparticle facets. This interaction occurs through the six carbon atoms of the π system. We investigate the structure–activity relationships (SARs) exhibited by these NPs in the efficient semi-hydrogenation of phenylacetylene (TOF = 3.85 s−1), 2-cyclohexen-1-one (TOF = 0.8 s−1), and 1,3-cyclohexadiene (TOF = 12.82 s−1) at 40 °C and 2–4 bar of H2 in BMIm·NTF2 ionic liquid. The enhanced activity and selectivity are attributed to (i) the formation of ionic liquid cages/membranes around the NPs akin to catalytically active membranes that tune the diffusion affinity of reactants, reactive intermediates, and products for catalytically active sites and (ii) the steric hindrance provided by the Pd–P bonds.

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