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1.
Artículo en Inglés | MEDLINE | ID: mdl-38844734

RESUMEN

Coronary artery aneurysms (CAAs) are morphologically classified as saccular and fusiform. There is still a great deal of clinical controversy as to which types of CAA are more likely to cause thrombosis. Therefore, the main objective of this study was to evaluate the trend of thrombus growth in CAAs with different morphologies and to assess the risk of possible long-term complications based on hemodynamic parameters. Utilizing computed tomography angiography (CTA) data from eight healthy coronary arteries, two distinct morphologies of coronary artery aneurysms (CAAs) were reconstructed. Distribution of four wall shear stress (WSS)-based indicators and three helicity indicators was analyzed in this study. Meanwhile, a thrombus growth model was introduced to analyze the thrombus formation in CAAs with different morphologies. The research results showed the distribution of most WSS indicators between saccular and fusiform CAAs was not statistically significant. However, due to the presence of a more pronounced helical flow pattern, irregular helical flow structure and longer time of flow stagnation in saccular CAAs during the cardiac cycle, the mean and maximum relative residence time (RRT) were significantly higher in saccular CAAs than in fusiform CAAs (P < 0.05). This may increase the risk of saccular coronary arteries leading to aneurysmal dilatation or even rupture. Although the two CAAs had similar rates of thrombosis, fusiform CAAs may more early cause obstruction of the main coronary flow channel where the aneurysm is located due to thrombosis growth. Thus, the risk of thrombosis in fusiform coronary aneurysms may warrant greater clinical concern.

2.
Cells ; 13(6)2024 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-38534378

RESUMEN

Pluripotent stem cells can be differentiated into all three germ-layers including ecto-, endo-, and mesoderm in vitro. However, the early identification and rapid characterization of each germ-layer in response to chemical and physical induction of differentiation is limited. This is a long-standing issue for rapid and high-throughput screening to determine lineage specification efficiency. Here, we present deep learning (DL) methodologies for predicting and classifying early mesoderm cells differentiated from embryoid bodies (EBs) based on cellular and nuclear morphologies. Using a transgenic murine embryonic stem cell (mESC) line, namely OGTR1, we validated the upregulation of mesodermal genes (Brachyury (T): DsRed) in cells derived from EBs for the deep learning model training. Cells were classified into mesodermal and non-mesodermal (representing endo- and ectoderm) classes using a convolutional neural network (CNN) model called InceptionV3 which achieved a very high classification accuracy of 97% for phase images and 90% for nuclei images. In addition, we also performed image segmentation using an Attention U-Net CNN and obtained a mean intersection over union of 61% and 69% for phase-contrast and nuclear images, respectively. This work highlights the potential of integrating cell culture, imaging technologies, and deep learning methodologies in identifying lineage specification, thus contributing to the advancements in regenerative medicine. Collectively, our trained deep learning models can predict the mesoderm cells with high accuracy based on cellular and nuclear morphologies.


Asunto(s)
Aprendizaje Profundo , Células Madre Pluripotentes , Animales , Ratones , Diferenciación Celular/fisiología , Estratos Germinativos/metabolismo , Mesodermo/metabolismo
3.
IBRO Neurosci Rep ; 16: 118-126, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38282758

RESUMEN

The functionality of human intelligence relies on the interaction and health of neurons, hence, quantifying neuronal morphologies can be crucial for investigating the functionality of the human brain. This paper proposes a deep learning (DL) based method for segmenting and quantifying neuronal structures in fluorescence microscopy images of developing neuronal cells cultured in vitro. Compared to the majority of supervised DL-based segmentation methods that heavily rely on creating exact corresponding masks of neuronal structures for the preparation of training samples, the proposed approach allows for imperfect annotation of neurons, as it only requires tracing the centrelines of the neurites. This ability accelerates the preparation of training data by several folds. Our proposed framework is built on a modified version of PSPNet with an EfficientNet backbone pre-trained on the CityScapes dataset. To handle the imperfectness of training samples, we incorporated a weighted combination of two loss functions, namely the Dice loss and Lovász loss functions, into our network. We evaluated the proposed framework and several other state-of-the-art methods on a published dataset of approximately 900 manually quantified cultured mouse neurons. Our results indicate a close correlation between the proposed method and manual quantification in terms of neuron length and the number of branches while demonstrating improved analysis speed. Furthermore, the proposed method achieved high accuracy in neuron segmentation, as evidenced by the evaluation of the neurons' length and number of branches.

4.
Adv Mater ; 36(18): e2310938, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38245860

RESUMEN

The development of metal-free bifunctional electrocatalysts for hydrogen and oxygen evolution reactions (HER and OER) is significant but rarely demonstrated. Porous organic polymers (POPs) with well-defined electroactive functionalities show superior performance in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Precise control of the active sites' local environment requires careful modulation of linkers through the judicious selection of building units. Here, a systematic strategy is introduced for modulating functionality to design and synthesize a series of thianthrene-based bifunctional sp2 C═C bonded POPs with hollow spherical morphologies exhibiting superior electrocatalytic activity. This precise structural tuning allowed to gain insight into the effects of heteroatom incorporation, hydrophilicity, and variations in linker length on electrocatalytic activity. The most efficient bifunctional electrocatalyst THT-PyDAN achieves a current density of 10 mA cm─2 at an overpotential (η10) of ≈65 mV (in 0.5 m H2SO4) and ≈283 mV (in 1 m KOH) for HER and OER, respectively. THT-PyDAN exhibits superior activity to all previously reported metal-free bifunctional electrocatalysts in the literature. Furthermore, these investigations demonstrate that THT-PyDAN maintains its performance even after 36 h of chronoamperometry and 1000 CV cycling. Post-catalytic characterization using FT-IR, XPS, and microscopic imaging techniques underscores the long-term durability of THT-PyDAN.

5.
Adv Mater ; 36(12): e2209919, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36635878

RESUMEN

The development of synthetic routes for the formation of robust porous organic polymers (POPs) with well-defined nanoscale morphology is fundamentally significant for their practical applications. The thermodynamic characteristics that arise from reversible covalent bonding impart intrinsic chemical instability in the polymers, thereby impeding their overall potential. Herein, a unique strategy is reported to overcome the stability issue by designing robust imidazole-linked POPs via tandem reversible/irreversible bond formation. Incorporating inherent rigidity into the secondary building units leads to robust microporous polymeric nanostructures with hollow-spherical morphologies. An in-depth analysis by extensive solid-state NMR (1D and 2D) study on 1H, 13C, and 14N nuclei elucidates the bonding and reveals the high purity of the newly designed imidazole-based POPs. The nitrogen-rich polymeric nanostructures are further used as metal-free electrocatalysts for water splitting. In particular, the rigid POPs show excellent catalytic activity toward the oxygen evolution reaction (OER) with long-term durability. Among them, the most efficient OER electrocatalyst (TAT-TFBE) requires 314 mV of overpotential to drive 10 mA cm-2 current density, demonstrating its superiority over state-of-the-art catalysts (RuO2 and IrO2).

6.
Biopolymers ; 115(2): e23567, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37792292

RESUMEN

Peptide nucleic acid (PNA) is a unique combination of peptides and nucleic acids. PNA can exhibit hydrogen bonding interactions with complementary nucleobases like DNA/RNA. Also, its polyamide backbone allows easy incorporation of biomolecules like peptides and proteins to build hybrid molecular constructs. Because of chimeric structural properties, PNA has lots of potential to build diverse nanostructures. However, progress in the PNA material field is still immature compared with its massive applications in antisense oligonucleotide research. Examples of well-defined molecular assemblies have been reported with PNA amphiphiles, self-assembling guanine-PNA monomers/dimers, and PNA-decorated nucleic acids/ polymers/ peptides. All these works indicate the great potential of PNA to be used as bionanomaterials. The review summarizes the recent reports on PNA-based nanostructures and their versatile applications. Additionally, this review shares a perspective to promote a better understanding of controlling molecular assembly by the systematic structural modifications of PNA monomers.


Asunto(s)
Nanoestructuras , Ácidos Nucleicos , Ácidos Nucleicos de Péptidos , Ácidos Nucleicos de Péptidos/química , Ácidos Nucleicos de Péptidos/metabolismo , ADN/química , Nanoestructuras/química , Péptidos
7.
Adv Mater ; 36(7): e2308606, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37816121

RESUMEN

Polymer solar cells (PSCs) are promising for efficient solar energy conversion, but achieving high efficiency and device longevity within a bulk-heterojunction (BHJ) structure remains a challenge. Traditional small-molecule acceptors (SMAs) in the BHJ blend show thermodynamic instability affecting the morphology. In contrast, tethered SMAs exhibit higher glass transition temperatures, mitigating these concerns. Yet, they might not integrate well with polymer donors, causing pronounced phase separation and overpurification of mixed domains. Herein, a novel ternary device is introduced that uses DY-P2EH, a tethered dimeric SMA with conjugated side-chains as host acceptor, and BTP-ec9, a monomeric SMA as secondary acceptor, which respectively possess hypomiscibility and hypermiscibility with the polymer donor PM6. This unique combination affords a parallel-connected ternary BHJ blend, leading to a hierarchical and stable morphology. The ternary device achieves a remarkable fill factor of 80.61% and an impressive power conversion efficiency of 19.09%. Furthermore, the ternary device exhibits exceptional stability, retaining over 85% of its initial efficiency even after enduring 1100 h of thermal stress at 85 °C. These findings highlight the potential advantage of tethered SMAs in the design of ternary devices with a refined hierarchical structure for more efficient and durable solar energy conversion technologies.

8.
Adv Mater ; 36(7): e2306681, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37805706

RESUMEN

Achieving precise control over the nanoscale morphology of bulk heterojunction films presents a significant challenge for the conventional post-treatments employed in organic solar cells (OSCs). In this study, a near-infrared photon-assisted annealing (NPA) strategy is developed for fabricating high-performance OSCs under mild processing conditions. It is revealed a top NIR light illumination, together with the bottom heating, enables the selective tuning of the molecular arrangement and assembly of narrow bandgap acceptors in polymer networks to achieve optimal morphologies, as well as the acceptor-rich top surface of active layers. The derived OSCs exhibit a remarkable power conversion efficiency (PCE) of 19.25%, representing one of the highest PCEs for the reported binary OSCs so far. Moreover, via the NPA strategy, it has succeeded in accessing top-illuminated flexible OSCs using thermolabile polyethylene terephthalate from mineral water bottles, displaying excellent mechanical stabilities. Overall, this work will hold the potential to develop organic solar cells under mild processing with various substrates.

9.
Sensors (Basel) ; 23(21)2023 Nov 02.
Artículo en Inglés | MEDLINE | ID: mdl-37960619

RESUMEN

In this paper, the study is supported by design, FEA simulation, and practical RF measurements on fabricated single-port-cavity-based acoustic resonator for gas sensing applications. In the FEA simulation, frequency domain analysis was performed to enhance the performance of the acoustic resonator. The structural and surface morphologies of the deposited ZnO as a piezoelectric layer have been studied using XRD and AFM. The XRD pattern of deposited bulk ZnO film indicates the perfect single crystalline nature of the film with dominant phase (002) at 2θ = 34.58°. The AFM micrograph indicates that deposited piezoelectric film has a very smooth surface and small grain size. In the fabrication process, use of bulk micro machined oxide (SiO2) for the production of a thin membrane as a support layer is adopted. A vector network analyzer (Model MS2028C, Anritsu) was used to measure the radio frequency response of the resonators from 1 GHz to 2.5 GHz. As a result, we have successfully fabricated an acoustic resonator operating at 1.84 GHz with a quality factor Q of 214 and an effective electromechanical coupling coefficient of 10.57%.

10.
PeerJ ; 11: e16115, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38025748

RESUMEN

Mass bleaching events and local anthropogenic influences have changed the benthic communities of many coral reefs with pronounced spatial differences that are linked to resilience patterns. The Gulf of Thailand is an under-investigated region with only few existing datasets containing long-term developments of coral reef communities using the same method at fixed sites. We thus analyzed benthic community data from seven reefs surrounding the island of Koh Phangan collected between 2014 and 2022. Findings revealed that the average live hard coral cover around Koh Phangan increased from 37% to 55% over the observation period, while turf algae cover decreased from 52% to 29%, indicating some recovery of local reefs. This corresponds to a mean increased rate of coral cover by 2.2% per year. The increase in live hard coral cover was mainly driven by plate-like corals, which quadrupled in proportion over the last decade from 7% to 28% while branching corals decreased in proportion from 9% to 2%. Furthermore, the hard coral genus richness increased, indicating an increased hard coral diversity. While in other reefs, increasing live hard coral cover is often attributed to fast-growing, branching coral species, considered more susceptible to bleaching and other disturbances, the reefs around Koh Phangan recovered mainly via growth of plate-like corals, particularly of the genus Montipora. Although plate-like morphologies are not necessarily more bleaching tolerant, they are important for supporting reef fish abundance and structural complexity on reefs, aiding reef recovery and sturdiness. Hence, our findings indicate that the intensity of local stressors around Kho Phangan allows reef recovery driven by some hard coral species.


Asunto(s)
Antozoos , Animales , Tailandia , Arrecifes de Coral , Peces
11.
Nanomaterials (Basel) ; 13(19)2023 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-37836277

RESUMEN

Anode materials based on the TiO2 nanoparticles of different morphologies were prepared using the hydrothermal method and characterized by various techniques, such as X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and N2 absorption. The TiO2 nanoparticles prepared were used as anode materials for lithium-ion batteries (LIBs), and their electrochemical properties were tested using discharging/charging measurements. The results showed that the initial morphology of the nanoparticles plays a minor role in battery performance after the first few cycles and that better capacity was achieved for TiO2 nanobelt morphology. The sharp drop in the specific capacity of LIB during their first cycles is examined by considering changes in the morphology of TiO2 particles and their porosity properties in terms of size and connectivity. The performance of TiO2 anode materials has also been assessed by considering their phase.

12.
Adv Colloid Interface Sci ; 318: 102958, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37453344

RESUMEN

Complex structures and morphologies in nature endow materials with unexpected properties and extraordinary functions. Biotemplating is an emerging strategy for replicating nature structures to obtain materials with unique morphologies and improved properties. Recently, efforts have been made to use bio-inspired species as a template for producing morphology-controllable catalysts. Fundamental information, along with recent advances in biotemplate metal-based catalysts are presented in this review through discussions of various structures and biotemplates employed for catalyst preparation. This review also outlines the recent progress on preparation routes of biotemplate catalysts and discusses how the properties and structures of these templates play a crucial role in the final performance of metal-based catalysts. Additionally, the application of bio-based metal and metal oxide catalysts is highlighted for various key energy and environmental technologies, including photocatalysis, fuel cells, and lithium batteries. Biotemplate metal-based catalysts display high efficiency in several energy and environmental systems. Note that this review provides guidance for further research in this direction.

13.
Infect Drug Resist ; 16: 4817-4834, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37520448

RESUMEN

Background: Sporotrichosis is a mycosis frequently caused by Sporothrix schenckii, Sporothrix brasiliensis, and Sporothrix globosa. The cell wall is a species-specific fungal structure with a direct role in activating the host's immune response. The current knowledge about anti-Sporothrix immunity comes from studies using S. schenckii or S. brasiliensis and murine cells. Macrophages and dendritic cells detect and eliminate pathogens, and although the function of these cells links innate with adaptive immunity, little is known about their interaction with Sporothrix spp. Methods: S. schenckii, S. brasiliensis, and S. globosa conidia or yeast-like cells were co-incubated with human monocyte-derived macrophages or dendritic cells, and the phagocytosis and cytokine stimulation were assessed. These interactions were also performed in the presence of specific blocking agents of immune receptors or fungal cells with altered walls to analyze the contribution of these molecules to the immune cell-fungus interaction. Results: Both types of immune cells phagocytosed S. globosa conidia and yeast-like cells to a greater extent, followed by S. brasiliensis and S. schenckii. Furthermore, when the wall internal components were exposed, the phagocytosis level increased for S. schenckii and S. brasiliensis, in contrast to S. globosa. Thus, the cell wall components have different functions during the interaction with macrophages and dendritic cells. S. globosa stimulated an increased proinflammatory response when compared to the other species. In macrophages, this was a dectin-1-, mannose receptor-, and TLR2-dependent response, but dectin-1- and TLR2-dependent stimulation in dendritic cells. For S. schenckii and S. brasiliensis, cytokine production was dependent on the activation of TLR4, CR3, and DC-SIGN. Conclusion: The results of this study indicate that these species are recognized by immune cells differently and that this may depend on both the structure and cell wall organization of the different morphologies.

14.
Int J Biol Macromol ; 249: 125994, 2023 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-37506788

RESUMEN

The limited anti-fungal activity of enzymatic hydrolysis lignin (EHL) has been a challenge in its direct application as a bamboo preservative. To address this issue, the cinnamaldehyde modification of EHL was carried out to introduce anti-fungal structures into the lignin matrix, effectively enhancing its anti-fungal activity. The results demonstrated that the minimal inhibitory concentrations of the modified lignin (EHL-DC) against Aspergillus niger significantly improved from 16 mg/mL to 1 mg/mL, with comparable enhancements in anti-fungal activity against other fungi. As a result of the modification, the EHL-DC is more prone to interact with fungal cell membranes, contributing to a roughened, shrunken hyphal surface and a decrease in mycelial biomass. Multiple characterization methods were employed to better grapple with the EHL-DC chemical changes. The nitrogen content increased from 2.3 % to 8.3 %, and alterations in elemental compositions further support the proposed reaction mechanism and its role in enhancing EHL's anti-fungal activity. This study offers novel insights into the high-value utilization of enzymatic hydrolysis lignin based on green chemistry principles.


Asunto(s)
Acroleína , Lignina , Lignina/química , Hidrólisis , Acroleína/farmacología , Biomasa
15.
Angew Chem Int Ed Engl ; 62(34): e202305945, 2023 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-37403785

RESUMEN

Polymerization-induced self-assembly (PISA) enables the synthesis at large scale of a wide variety of functional nanoparticles. However, a large number of works are related to controlled radical polymerization (CRP) methods and are generally undertaken at elevated temperatures (>50 °C). Here is the first report on methacrylate-based nanoparticles fabricated by group transfer polymerization-induced self-assembly (GTPISA) in non-polar media (n-heptane). This GTPISA process is achieved at room temperature (RT) using 1-methoxy-1-(trimethylsiloxy)-2-methylprop-1-ene (MTS) and tetrabutylammonium bis-benzoate (TBABB) as initiator and organic catalyst, respectively. Under these conditions, well-defined metal-free and colorless diblock copolymers are produced with efficient crossover from the non-polar stabilizing poly(lauryl methacrylate) (PLMA) block to the non-soluble poly(benzyl methacrylate) (PBzMA) segment. The resulting PLMA-b-PBzMA block copolymers simultaneously self-assemble into nanostructures of various sizes and morphologies. GTPISA in non-polar solvent proceeds rapidly at RT and avoids the use of sulfur or halogenated compounds or metallic catalysts associated with the implementation of CRP methods, thus expanding the potential of PISA formulations for applications in non-polar environments.

16.
Molecules ; 28(11)2023 Jun 02.
Artículo en Inglés | MEDLINE | ID: mdl-37298994

RESUMEN

This study focuses on the thermal properties and structural features of blends consisting of thermoplastic starch (TPS) and poly(ethylene-co-methacrylic acid) copolymer (EMAA) or its ionomer form (EMAA-54Na). The aim is to investigate how carboxylate functional groups of the ionomer form intervene in blends compatibility at the interface of the two materials and how this impacts their properties. Two series of blends (TPS/EMAA and TPS/EMAA-54Na) were produced with an internal mixer, with TPS compositions between 5 and 90 wt%. Thermogravimetry shows two main weight losses, indicating that TPS and the two copolymers are primarily immiscible. However, a small weight loss existing at intermediate degradation temperature between those of the two pristine components reveals specific interactions at the interface. At a mesoscale level, scanning electron microscopy confirmed thermogravimetry results and showed a two-phase domain morphology, with a phase inversion at around 80 wt% TPS, but also revealed a different surface appearance evolution between the two series. Fourier-transformed infrared spectroscopy analysis also revealed discrepancies in fingerprint between the two series of blends, analysed in terms of additional interactions in TPS/EMAA-54Na coming from the supplementary sodium neutralized carboxylate functions of the ionomer.


Asunto(s)
Polietileno , Almidón , Almidón/química , Polímeros , Ácidos Carboxílicos , Etilenos
17.
Infect Drug Resist ; 16: 3065-3072, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37222986

RESUMEN

Background: Candida auris is a pathogen first found in external ear canal, becoming a major threat to global health. Here, we describe a candidemia case caused by a novel drug-resistant Candida auris strain. Case Presentation: An 80-year-old patient, with multiple serious medical conditions, was suffered from candidemia caused by Candida auris, died 9 days after admission in our hospital. Phylogenetic analysis indicates that this C. auris isolate (designated BJCA003) belongs to the South Asian clade, carries the Y132F mutation in the protein Erg11. And antibiotic susceptibility test indicated that BJCA003 is resistant to fluconazole and amphotericin B, not susceptible to caspofungin. In addition, this strain has multiple colony and cellular morphologies under different culture conditions. Conclusion: Strain BJCA003 is a novel drug resistant C. auris strain in mainland China, the Y132F mutation in Erg11 may attribute to fluconazole-resistance, alarming that we still face more challenges about C. auris.

18.
Small ; 19(38): e2302403, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37211706

RESUMEN

The highest specific energy absorption (SEA) of interlocked micron-thickness carbon nanotube (IMCNT) films subjected to micro-ballistic impact is reported in this paper. The SEA of the IMCNT films ranges from 0.8 to 1.6 MJ kg-1 , the greatest value for micron-thickness films to date. The multiple deformation-induced dissipation channels at the nanoscale involving disorder-to-order transition, frictional sliding, and entanglement of CNT fibrils contribute to the ultra-high SEA of the IMCNT. Furthermore, an anomalous thickness dependency of the SEA is observed, that is, the SEA increases with increasing thickness, which should be ascribed to the exponential growth in nano-interface that further boosts the energy dissipation efficiency as the film thickness increases. The results indicate that the developed IMCNT overcomes the size-dependent impact resistance of traditional materials and demonstrates great potential as a bulletproof material for high-performance flexible armor.

19.
J Mol Model ; 29(6): 179, 2023 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-37195366

RESUMEN

CONTEXT: 3,4-bis(3-nitrofurazan-4-yl)furoxan (DNTF) is a new energetic compound with high energy and high density, and it is an important component of propellant and melt cast explosive. In order to study the effect of solvent on the growth morphology of DNTF, the growth plane of DNTF in vacuum is predicted by attachment energy (AE) model, and then the modified attachment energy of each growth plane in different solvents is calculated by molecular dynamics simulation. The morphology of crystal in solvent is predicted by modified attachment energy (MAE) model. The factors affecting crystal growth in solvent environment are analyzed by mass density distribution, radial distribution function and diffusion coefficient. The results show that the growth morphology of crystal in solvent is not only related to the adsorption strength of solvent to crystal plane, but affected by the attraction of crystal plane to solute. The hydrogen bond plays an important role in the adsorption strength between solvent and crystal plane. The polarity of solvent has a great influence on the crystal morphology, and the interaction between the solvent with stronger polarity and the crystal plane is stronger. The morphology of DNTF in n-butanol solvent is closer to spherical, which can effectively reduce the sensitivity of DNTF. METHODS: The molecular dynamics simulation is carried out under the COMPASS force field of Materials Studio software. Gaussian software is used to calculate the electrostatic potential of DNTF at B3LYP-D3/6-311 + G (d, p) theoretical level.

20.
Int J Bioprint ; 9(2): 656, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37065672

RESUMEN

The printing accuracy of polymer melt electrowriting is adversely affected by the residual charge entrapped within the fibers, especially for three-dimensional (3D) structured materials or multilayered scaffolds with small interfiber distances. To clarify this effect, an analytical charge-based model is proposed herein. The electric potential energy of the jet segment is calculated considering the amount and distribution of the residual charge in the jet segment and the deposited fibers. As the jet deposition proceeds, the energy surface assumes different patterns, which constitute different modes of evolution. The manner in which the various identified parameters affect the mode of evolution are represented by three charge effects, including the global, local, and polarization effect. Based on these representations, typical modes of energy surface evolution are identified. Moreover, the lateral characteristic curve and characteristic surface are advanced to analyze the complex interplay between fiber morphologies and residual charge. Different parameters contribute to this interplay either by affecting residual charge, fiber morphologies, or the three charge effects. To validate this model, the effects of lateral location and grid number (i.e., number of fibers printed in each direction) on the fiber morphologies are investigated. Moreover, the "fiber bridging" phenomenon in parallel fiber printing is successfully explained. These results help to comprehensively understand the complex interplay between the fiber morphologies and the residual charge, thus furnishing a systematic workflow to improve printing accuracy.

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