36 results match your criteria: "Institute for Nanostructures[Affiliation]"

Non-Intrusive Monitoring of Vital Signs in the Lower Limbs Using Optical Sensors.

Sensors (Basel)

January 2025

Institute for Nanostructures, Nanomodelling and Nanofabrication (i3N), Department of Physics, University of Aveiro, 3810-193 Aveiro, Portugal.

Invisible health monitoring is currently a topic of global interest within the scientific community. Sensorization of everyday objects can provide valuable health information without requiring any changes in people's routines. In this work, a feasibility study of photoplethysmography (PPG) acquisition in the lower limbs for continuous and real-time monitoring of the vital signs, including heart rate (HR) and respiratory rate (RR), is presented.

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Electrospun membranes are compact structures with small pore sizes that hinder cell infiltration, resulting in membranes with cells attached only to the external surface rather than throughout the entire volume. Thus, there is a need to increase the pore size of electrospun membranes maintaining their structural similarity to the extracellular matrix. In this work, we used glucose crystals embedded in polyethylene oxide (PEO) fibers to create large pores in poly(lactic acid) (PLA) electrospun membranes to allow for cellular infiltration.

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Next-generation chemotherapy treatments based on black hole algorithms: From cancer remission to chronic disease management.

Comput Biol Med

September 2024

Center for Mechanical Technology & Automation (TEMA), Department of Mechanical Engineering, University of Aveiro, Aveiro, Portugal; Intelligent Systems Associate Laboratory (LASI), Guimarães, Portugal.

Problem: Therapeutic planning strategies have been developed to enhance the effectiveness of cancer drugs. Nevertheless, their performance is highly limited by the inefficient biological representativeness of predictive tumor growth models, which hinders their translation to clinical practice.

Objective: This study proposes a disruptive approach to oncology based on nature-inspired control using realistic Black Hole physical laws, in which tumor masses are trapped to experience attraction dynamics on their path to complete remission or to become a chronic disease.

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Nanocrystalline diamond (NCD) films are attractive for many applications due to their smooth surfaces while holding the properties of diamond. However, their growth rate is generally low using common Ar/CH with or without H chemistry and strongly dependent on the overall growth conditions using microwave plasma chemical vapor deposition (MPCVD). In this work, incorporating a small amount of N and O additives into CH/H chemistry offered a much higher growth rate of NCD films, which is promising for some applications.

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Precise positioning of gamma ray interactions in multiplexed pixelated scintillators using artificial neural networks.

Biomed Phys Eng Express

June 2024

Institute for Nanostructures, Nanomodelling and Nanofabrication (i3N), University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.

. The positioning ofray interactions in positron emission tomography (PET) detectors is commonly made through the evaluation of the Anger logic flood histograms. machine learning techniques, leveraging features extracted from signal waveform, have demonstrated successful applications in addressing various challenges in PET instrumentation.

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Electrospun Polycaprolactone Membranes Expanded with Chitosan Granules for Cell Infiltration.

Polymers (Basel)

February 2024

Centro de Investigação de Materiais, Institute for Nanostructures, Nanomodelling and Nanofabrication, CENIMAT-I3N, 2829-516 Caparica, Portugal.

The small pore size of electrospun membranes prevents their use as three-dimensional scaffolds. In this work, we produced polycaprolactone (PCL) electrospun fibrous membranes with expanded pores by incorporating chitosan (CS) granules into the PCL solution. Scanning electron microscopy images confirmed the presence of the CS granules embedded in the PCL fibers, creating an open structure.

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Cu thin films and Cu O microstructures were partially converted to the Metal-Organic Frameworks (MOFs) Cu (BTC) or Cu(TCPP) using an electrochemical process with a higher control and at milder conditions compared to the traditional solvothermal MOF synthesis. Initially, either a Cu thin film was sputtered, or different kinds of Cu or Cu O microstructures were electrochemically deposited onto a conductive ITO glass substrate. Then, these Cu thin films or Cu-based microstructures were subsequently coated with a thin layer of either Cu (BTC) or Cu(TCPP) by controlled anodic dissolution of the Cu-based substrate at room temperature and in the presence of the desired organic linker molecules: 1,3,5-benzenetricarboxylic acid (BTC) or photoactive 4,4',4'',4'''-(Porphine-5,10,15,20-tetrayl) tetrakis(benzoic acid) (TCPP) in the electrolyte.

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Organosulfur and Organoselenium Functionalized Benzimidazo[1,2-a]quinolines: From Experimental and Theoretical Photophysics to All-Solution-Processed OLEDs.

J Fluoresc

May 2024

Instituto de Química, Departamento de Química Orgânica, Universidade Federal do Rio Grande do Sul (UFRGS), PO Box 15003, Porto Alegre, Rio Grande do Sul, 91501-970, Brazil.

In this study, we present the synthesis of benzimidazo[1,2-a] quinoline-based heterocycles bearing organosulfur and organoselenium moieties through transition-metal-free cascade reactions involving a sequential intermolecular aromatic nucleophilic substitution (SN). Both sulfur and selenium derivatives presented absorption maxima located around 355 nm related to spin and symmetry allowing electronic π-π* transitions, and fluorescence emission at the violet-blue region (~440 nm) with relatively large Stokes shift. The fluorescence quantum yields were slightly influenced by the chalcogen, with the sulfur derivatives presenting higher values than the selenium analogs.

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Development of Efficient OLEDs from Solution Deposition.

J Vis Exp

November 2022

Department of Physics and i3N, Institute for Nanostructures, Nanomodulation and Nanofabrication, University of Aveiro;

The use of highly efficient organic emitters based on the thermally activated delayed fluorescence (TADF) concept is interesting due to their 100% internal quantum efficiency. Presented here is a solution deposition method for the fabrication of efficient organic light-emitting diodes (OLEDs) based on a TADF emitter in a simple device structure. This fast, low-cost, and efficient process can be used for all OLED emissive layers that follow the host-guest concept.

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Two three-dimensional (3-D) polycyanidometallate-based luminescent thermometers with the general formula {LnCo(CN)(4-benpyo)(HO)·7HO} Ln = (Dy(III)(), Eu(III)()), based on the red-emissive diamagnetic linker [Co(CN)] and the bulky pyridine derivative that possesses the N-oxide moiety, 4-benzyloxy-pyridine N-oxide (benpyo), were prepared for the first time. The structure of compound has been determined by single-crystal X-ray crystallography while the purity and structure of have been confirmed by CHN, Fourier transform infrared spectroscopy (FT-IR), and powder X-ray diffraction (PXRD) analysis. Magnetic AC susceptibility measurements at zero field show no single-molecule magnet (SMM) behavior indicating fast relaxation operating in .

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A guideline proposal for mice preparation and care in F-FDG PET imaging.

EJNMMI Res

August 2022

Institute for Nanostructures, Nanomodelling and Nanofabrication (i3N), Department of Physics, University of Aveiro (DFis-UA), 3810-193, Aveiro, Portugal.

The experimental outcomes of small-animal positron emission tomography (PET) imaging with F-labelled fluorodeoxyglucose (F-FDG) can be particularly compromised by animal preparation and care. Several works intend to improve research reporting and amplify the quality and reliability of published research. Though these works provide valuable information to plan and conduct animal studies, manuscripts describe different methodologies-standardization does not exist.

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Herein, we report the synthesis and characterization of two Pt(II) coordination compounds, the new platinum(II)[,'-bis(salicylidene)-3,4-diaminobenzophenone)] ([Pt(sal-3,4-ben)]) and the already well-known platinum(II)[,'-bis(salicylidene)-o-phenylenediamine] ([Pt(salophen)]), along with their application as guests in a poly [9,9-dioctylfluorenyl-2,7-diyl] (PFO) conjugated polymer in all-solution processed single-layer white organic light-emitting diodes. Completely different performances were achieved: 2.2% and 15.

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Development of a New Integrated System for Vital Sign Monitoring in Small Animals.

Sensors (Basel)

June 2022

Institute for Nanostructures, Nanomodelling and Nanofabrication (i3N), Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal.

Monitoring the vital signs of mice is an essential practice during imaging procedures to avoid populational losses and improve image quality. For this purpose, a system based on a set of devices (piezoelectric sensor, optical module and thermistor) able to detect the heart rate, respiratory rate, body temperature and arterial blood oxygen saturation (SpO2) in mice anesthetized with sevoflurane was implemented. Results were validated by comparison with the reported literature on similar anesthetics.

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We report on the optoelectronic characteristics of-NiO/-Si heterojunction photodiode for broadband photodetection, fabricated by depositing a-type NiO thin film onto a commercial-type silicon substrate using pulsed laser deposition (PLD) technique. The structural properties of the PLD-grown-NiO material were analysed by means of x-ray diffraction and x-ray photoelectron spectroscopy, confirming its crystalline nature and revealing the presence of Ni vacancies, respectively. Hall measurements confirmed the-type semiconducting nature of the NiO thin film having a carrier concentration of 8.

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Graded Morphologies and the Performance of PffBT4T-2OD:PCBM Devices Using Additive Choice.

Nanomaterials (Basel)

December 2021

LEPABE-Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.

The impact of several solvent processing additives (1-chloronaphthalene, methylnaphthalene, hexadecane, 1-phenyloctane, and p-anisaldehyde), 3% / in o-dichlorobenzene, on the performance and morphology of poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3‴-di(2-octyldodecyl)-2,2',5',22033,5″,2‴-quaterthiophen-5,5‴-diyl)] (PffBT4T-2OD):[6,6]-phenyl-C71-butyric acid methyl ester (PCBM)-based polymer solar cells was investigated. Some additives were shown to enhance the power conversion efficiency (PCE) by ~6%, while others decreased the PCE by ~17-25% and a subset of the additives tested completely eliminated any power conversion efficiency and the operation as a photovoltaic device. Grazing-Incidence Wide Angle X-ray Scattering (GIWAXS) revealed a clear stepwise variation in the crystallinity of the systems when changing the additive between the two extreme situations of maximum PCE (1-chloronaphthalene) and null PCE (hexadecane).

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Chronic cocaine use has been shown to lead to neurotoxicity in rodents and humans, being associated with high morbidity and mortality rates. However, recreational use, which may lead to addictive behavior, is often neglected. This occurs, in part, due to the belief that exposure to low doses of cocaine comes with no brain damage risk.

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Molybdenum Oxide Thin Films Grown on Flexible ITO-Coated PET Substrates.

Materials (Basel)

February 2021

Centre for Research in Ceramics and Composite Materials (CICECO), Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal.

Molybdenum oxide thin films were deposited on stiff and flexible substrates by reactive DC magnetron sputtering. Two sets of samples were prepared. The first with different O/Ar flow rate ratios and the second, fixing the oxygen content, with different time of deposition.

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Anisotropic Magnetic Resonance in Random Nanocrystal Quantum Dot Ensembles.

ACS Omega

May 2020

i3N-Institute for Nanostructures, Nanomodelling and Nanofabrication, Department of Physics, University of Aveiro, 3810-193 Aveiro, Portugal.

Magnetic anisotropy critically determines the utility of magnetic nanocrystals (NCs) in new nanomagnetism technologies. Using angular-dependent electron magnetic resonance (EMR), we observe magnetic anisotropy in isotropically arranged NCs of a nonmagnetic material. We show that the shape of the EMR angular variation can be well described by a simple model that considers magnetic dipole-dipole interactions between dipoles randomly located in the NCs, most likely due to surface dangling bonds.

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The impact of fullerene side chain functionalization with thiophene and carbazole groups on the device properties of bulk-heterojunction polymer:fullerene solar cells is discussed through a systematic investigation of material blends consisting of the conjugated polymer poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3‴-di(2-octyldodecyl)-2,2';5',2″;5″,2‴-quaterthiophen-5,5‴-diyl)] (PffBT4T-2OD) as donor and C or C fulleropyrrolidines as acceptors. The photovoltaic performance clearly depended on the molecular structure of the fulleropyrrolidine substituents although no direct correlation with the surface morphology of the photoactive layer, as determined by atomic force microscopy, could be established. Although some fulleropyrrolidines possess favorable lowest unoccupied molecular orbital levels, when compared to the standard PCBM, they originated OPV cells with inferior efficiencies than PCBM-based reference cells.

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Mixed-Host Systems with a Simple Device Structure for Efficient Solution-Processed Organic Light-Emitting Diodes of a Red-Orange TADF Emitter.

ACS Omega

February 2020

Department of Physics and i3N-Institute for Nanostructures, Nanomodulation and Nanofabrication, University of Aveiro, 3810-193 Aveiro, Portugal.

Charge balance, concentration quenching, and exciton confinement are the most important factors for realizing the use of thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes. Red-orange organic light-emitting diodes of a TADF emitter 2-[4 (diphenylamino)phenyl]-10,10-dioxide-9-thioxanthen-9-one (TXO-TPA) have been reported by doping in a mixed p-type host system of poly(-vinylcarbazole) (PVK) and 1,3-bis(-carbazolyl)benzene (mCP) via solution-processed. We have demonstrated the peak external quantum efficiency of 9.

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Simulation of Image-Guided Intervention in Medical Imaging Education.

J Med Imaging Radiat Sci

June 2020

School of Health Sciences (ESSUA), University of Aveiro, Aveiro, Portugal; Institute of Electronics and Informatics Engineering of Aveiro (IEETA), University of Aveiro, Aveiro, Portugal.

Introduction/background: Medical imaging education programs across Europe, despite their variability, include clinical practice as a guarantee of quality because learning in a clinical context is more effective and allows for constructive qualification of students. Learning in a clinical simulation context is a strategy to promote simulated clinical experience and assure patient safety. In this work, a learning experience, consisting of simulating a pacemaker implantation, implemented over 3 years with students pursuing the Medical Imaging and Radiotherapy degree at the University of Aveiro was evaluated.

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Towards Highly Efficient TADF Yellow-Red OLEDs Fabricated by Solution Deposition Methods: Critical Influence of the Active Layer Morphology.

Nanomaterials (Basel)

January 2020

Department of Physics and i3N-Institute for Nanostructures, Nanomodulation and Nanofabrication, University of Aveiro, 3810-193 Aveiro, Portugal.

Organic light-emitting diodes (OLEDs) based on thermally activated delayed fluorescence emitters (TADF) in simple device structures fabricated by solution processing are strongly dependent on a suitable host molecular conformation and morphology. Herein, we report the fabrication of highly efficient yellow-red TADF-based OLEDs via solution processing in a simple, two-organic-layer device structure. The devices were fabricated at different weight concentrations of 5%, 8%, and 10% emitter in an n-/p-type mixed host matrix, and their characteristics were studied.

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Toxicity Evaluation of Quantum Dots (ZnS and CdS) Singly and Combined in Zebrafish ().

Int J Environ Res Public Health

December 2019

UCIBIO-Applied Molecular Biosciences Unit, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal.

The exponential growth of nanotechnology has led to the production of large quantities of nanomaterials for numerous industrial, technological, agricultural, environmental, food and many other applications. However, this huge production has raised growing concerns about the adverse effects that the release of these nanomaterials may have on the environment and on living organisms. Regarding the effects of QDs on aquatic organisms, existing data is scarce and often contradictory.

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Novel C and C -methyl-fulleropyrrolidine derivatives, containing both electron withdrawing and electron donating substituent groups, were synthesized by the well-known Prato reaction. The corresponding highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital (LUMO) energy levels were determined by cyclic voltammetry, from the onset oxidation and reduction potentials, respectively. Some of the novel fullerenes have higher LUMO levels than the standards PCBM and PCBM.

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Effect of the Host on Deep-Blue Organic Light-Emitting Diodes Based on a TADF Emitter for Roll-Off Suppressing.

Nanomaterials (Basel)

September 2019

Department of Physics and i3N-Institute for Nanostructures, Nanomodulation and Nanofabrication, University of Aveiro, 3810-193 Aveiro, Portugal.

To achieve significant efficiency and low roll-off in thermally activated delayed fluorescence (TADF) material organic light-emitting diodes (OLEDs), it is essential to choose a host that has suitable high triplet energy (T) and bipolar character to boost the TADF characteristics as a dopant and avoid exciton annihilation. Herein, we present the effect of different host materials on the efficiency of organic light-emitting diodes (OLEDs) based on bis[4-(3,6 dimethoxycarbazole)phenyl]sulfone (DMOC-DPS) deep-blue emitter. The devices with 10 wt.

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