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1.
Food Chem ; 458: 140188, 2024 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-38964098

RESUMO

Oleogels have been used in the gelled surimi products to replace animal fats due to its structure characteristics. The effect of structure characteristics in fish oil oleogels on the mechanism of oil/water retention was investigated in meat emulsions. Beeswax assembly improved the oil and water retention. The unsaturation degree of fatty acids lowered the mobility of bound water, immobilized water as well as bound fat in the fish oil oleogel, but enhanced the mobility of free water and protons of unsaturated fatty acids. Beeswax addition and oil phase characteristics could enhance ß-sheets, disulfide bonds and hydrophobic force to improve the viscoelasticity, gel strength and oil/water retention. Beeswax assembly facilitated the tight micro-sol network and filling effect, and high unsaturation degree promoted the emulsification effect, thus reducing phase transition temperature and juice loss. The study could lay the foundation for development of gelled shrimp meat products with EPA and DHA.

2.
Materials (Basel) ; 17(13)2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38998380

RESUMO

Ultra High-Performance Concrete (UHPC) is a cement-based composite material with great strength and durability. Fibers can effectively increase the ductility, strength, and fracture energy of UHPC. This work describes the impacts of individual or hybrid doping of basalt fiber (BF) and steel fiber (SF) on the mechanical properties and microstructure of UHPC. We found that under individual doping, the effect of BF on fluidity was stronger than that of SF. Moreover, the compressive, flexural, and splitting tensile strength of UHPC first increased and then decreased with increasing BF dosage. The optimal dosage of BF was 1%. At a low content of fiber, UHPC reinforced by BF demonstrated greater flexural strength than that reinforced by SF. SF significantly improved the toughness of UHPC. However, a high SF dosage did not increase the strength of UHPC and reduced the splitting tensile strength. Secondly, under hybrid doping, BF was partially substituted for SF to improve the mechanical properties of hybrid fiber UHPC. Consequently, when the BF replacement rate increased, the compressive strength of UHPC gradually decreased; on the other hand, there was an initial increase in the fracture energy, splitting tensile strength, and flexural strength. The ideal mixture was 0.5% BF + 1.5% SF. The fluidity of UHPC with 1.5% BF + 0.5% SF became the lowest with a constant total volume of 2%. The microstructure of hydration products in the hybrid fiber UHPC became denser, whereas the interface of the fiber matrix improved.

3.
Food Res Int ; 188: 114434, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38823828

RESUMO

In this work, dispersions were prepared with commercial pea protein isolate (PPI) and subjected to different (i) high pressure homogenization (HPH) intensities (0 - 200 MPa) (room temperature, pH 7) or (ii) environmental conditions (60 °C, pH 7 or pH 12) to generate dispersions with distinct protein molecular and microstructural characteristics, impacting protein solubility. Besides, protein digestion was analyzed following the static INFOGEST in vitro digestion protocol. Generally, increasing pressure of the homogenization treatment was linked with decreasing particle sizes and enhanced protein digestion. More specifically, the dispersion that did not undergo HPH (0 MPa) as well as the dispersion treated at 60 °C, pH 7, had highly similar microstructures, consisting of large irregular particles (10 - 500 µm) with shell-like structures, and exhibited low solubility (around 15 % and 28 %, respectively), which resulted in limited proteolysis (35 % and 42 %, respectively). In contrast, the dispersion subjected to HPH at 100 MPa and the dispersion treated at 60 °C, pH 12 also had similar microstructures with small and homogeneous particles (<1 µm), and exhibited relatively good solubility (54 % and 31 %, respectively), which led to enhanced protein digestion levels (87 % and 74 %, respectively). This study highlights the potential of food processing on macronutrient (micro)structure and further gastrointestinal stability and functionality.


Assuntos
Digestão , Manipulação de Alimentos , Tamanho da Partícula , Proteínas de Ervilha , Pressão , Solubilidade , Proteínas de Ervilha/química , Concentração de Íons de Hidrogênio , Manipulação de Alimentos/métodos , Proteólise , Pisum sativum/química , Temperatura
4.
Int J Biol Macromol ; 266(Pt 1): 131191, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38552680

RESUMO

The excessive water sensitivity of hydroxypropyl methylcellulose (HPMC) films prevent them from being used extensively. In order to overcome this limitation, superhydrophobic HPMC films were meticulously crafted through the utilization of a composite of polydimethylsiloxane (PDMS) and ball-milled rice starch, corn starch, or potato starch (RS/CS/PS) for the coating process. Initially possessing hydrophilic properties, the HPMC Film (CA = 49.3 ± 1.8°) underwent a transformative hydrophobic conversion upon the application of PDMS, resulting in a static contact angle measuring up to 103.4 ± 2.0°. Notably, the synergistic combination of PDMS-coated HPMC with ball-milled starch demonstrated exceptional superhydrophobic attributes. Particularly, the treated HPMC-based film, specifically the HP-CS-2 h film, showcased an impressive contact angle of 170.5° alongside a minimal sliding angle of 5.2°. The impact of diverse starch types and the ball milling treatment on the PDMS/starch coatings and HPMC film was thoroughly examined using scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXS), and particle size analysis. These studies demonstrated that the low surface energy and roughness required for the creation of superhydrophobic HPMC-based films were imparted by the hierarchical structure formed by the application of PDMS/ball-milled starch. CHEMICAL COMPOUNDS STUDIED IN THIS ARTICLE: Polydimethylsiloxane (PubChem CID: 24764); Hydroxypropyl methylcellulose (PubChem CID: 671); Ethyl acetate (PubChem CID: 8857).


Assuntos
Dimetilpolisiloxanos , Interações Hidrofóbicas e Hidrofílicas , Derivados da Hipromelose , Amido , Amido/química , Dimetilpolisiloxanos/química , Derivados da Hipromelose/química , Água/química
5.
Int J Mol Sci ; 25(5)2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38474252

RESUMO

Na-V-P-Nb-based materials have gained substantial recognition as cathode materials in high-rate sodium-ion batteries due to their unique properties and compositions, comprising both alkali and transition metal ions, which allow them to exhibit a mixed ionic-polaronic conduction mechanism. In this study, the impact of introducing two transition metal oxides, V2O5 and Nb2O5, on the thermal, (micro)structural, and electrical properties of the 35Na2O-25V2O5-(40 - x)P2O5 - xNb2O5 system is examined. The starting glass shows the highest values of DC conductivity, σDC, reaching 1.45 × 10-8 Ω-1 cm-1 at 303 K, along with a glass transition temperature, Tg, of 371 °C. The incorporation of Nb2O5 influences both σDC and Tg, resulting in non-linear trends, with the lowest values observed for the glass with x = 20 mol%. Electron paramagnetic resonance measurements and vibrational spectroscopy results suggest that the observed non-monotonic trend in σDC arises from a diminishing contribution of polaronic conductivity due to the decrease in the relative number of V4+ ions and the introduction of Nb2O5, which disrupts the predominantly mixed vanadate-phosphate network within the starting glasses, consequently impeding polaronic transport. The mechanism of electrical transport is investigated using the model-free Summerfield scaling procedure, revealing the presence of mixed ionic-polaronic conductivity in glasses where x < 10 mol%, whereas for x ≥ 10 mol%, the ionic conductivity mechanism becomes prominent. To assess the impact of the V2O5 content on the electrical transport mechanism, a comparative analysis of two analogue series with varying V2O5 content (10 and 25 mol%) is conducted to evaluate the extent of its polaronic contribution.


Assuntos
Nióbio , Fosfatos , Fosfatos/química , Vidro/química , Íons , Espectroscopia de Ressonância de Spin Eletrônica , Sódio/química , Cerâmica/química
6.
Polymers (Basel) ; 16(3)2024 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-38337242

RESUMO

Particle- or fiber-reinforced polymer composites with controlled orientations are attracting interest and applications producing innovative materials, biological constructs, and energy devices. To gain the controlled orientations, filed-assisted synthesis is widely selected for its easy operation and control. In this paper, we designed magnetic field-assisted equipment and synthesized a magnetic polymer composite Fe3O4/PMMA with a well-arranged layers structure by combining the magnetic field with atom transfer radical polymerization (ATRP). During the polymerization of polymer composites, the magnetic nanoparticles were surrounded by monomers. With the growth of polymer chains, the magnetic particles pushed polymer chains to move according to a specific direction and form a well-arranged structure under the magnetic fields. The existence of a well-arranged layered structure of the composites gives potential guidance for controlling the micro-structure by adding an extra field during the polymerization process. The experimental results provided a possible design to influence the macroscale properties through control of the micro-structure of polymer composites.

7.
Materials (Basel) ; 17(2)2024 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-38255474

RESUMO

Sodium-phosphate-based glass-ceramics (GCs) are promising materials for a wide range of applications, including solid-state sodium-ion batteries, microelectronic packaging substrates, and humidity sensors. This study investigated the impact of 24 h heat-treatments (HT) at varying temperatures on Na-Ge-P glass, with a focus on (micro)structural, electrical, and dielectric properties of prepared GCs. Various techniques such as powder X-ray diffraction (PXRD), infrared spectroscopy-attenuated total reflection (IR-ATR), and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) were employed. With the elevation of HT temperature, crystallinity progressively rose; at 450 °C, the microstructure retained amorphous traits featuring nanometric grains, whereas at 550 °C, HT resulted in fully crystallized structures characterized by square-shaped micron-scale grains of NaPO3. The insight into the evaluation of electrical and dielectric properties was provided by Solid-State Impedance Spectroscopy (SS-IS), revealing a strong correlation with the conditions of controlled crystallization and observed (micro)structure. Compared to the initial glass, which showed DC conductivity (σDC) on the order of magnitude 10-7 Ω-1 cm-1 at 393 K, the obtained GCs exhibited a lower σDC ranging from 10-8 to 10-10 Ω-1 cm-1. With the rise in HT temperature, σDC further decreased due to the crystallization of the NaPO3 phase, depleting the glass matrix of mobile Na+ ions. The prepared GCs showed improved dielectric parameters in comparison to the initial glass, with a noticeable increase in dielectric constant values (~20) followed by a decline in dielectric loss (~10-3) values as the HT temperatures rise. Particularly, the GC obtained at @450 stood out as the optimal sample, showcasing an elevated dielectric constant and low dielectric loss value, along with moderate ionic conductivity. This research uncovers the intricate relationship between heat-treatment conditions and material properties, emphasizing that controlled crystallization allows for precise modifications to microstructure and phase composition within the remaining glassy phase, ultimately facilitating the fine-tuning of material properties.

8.
Environ Sci Pollut Res Int ; 31(3): 4671-4685, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38110675

RESUMO

The fly ash-based geopolymer (FABG) containing slag has distinct advantages in field applications. In this work, given that the activator modulus is a significant parameter affecting the properties of FABG, the influence mechanism of activator modulus (SiO2/Na2O from 1.1 to 1.5) on the macro-mechanical properties and micro-structure composition of FABG containing slag is explored. According to the experimental results, the early product of FABG containing slag is mainly C-A-S-H gel, and N-(C)-A-S-H gel with high cross-linking degree is formed at a later stage. Both C-A-S-H and N-A-S-H gels are distinguished in reaction products by using 29Si NMR. The Si/Al ratio of N-A-S-H gel and C-A-S-H gel decreases with the increase of modulus, resulting in an increase of MCL in C-A-S-H. Appropriate activator modulus can effectively activate slag and fly ash to yield more gels and form a more uniform and dense micro-structure, resulting in a lower threshold pore size and macroporosity, and an associated increase of the material strength. Meanwhile, the gel amount has a positive effect on the strength development in the FABG.


Assuntos
Cinza de Carvão , Gastrópodes , Animais , Dióxido de Silício , Géis
9.
Gels ; 9(12)2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-38131933

RESUMO

This study employed a coarse-grained Monte Carlo (MC) simulation to investigate the radiation-induced polymerisation of methacrylic acid (MAA) in an aqueous solution. This method provides an alternative to traditional kinetic models, enabling a detailed examination of the micro-structure and growth patterns of MAA polymers, which are often not captured in other approaches. In this work, we generated multiple clones of a simulation box, each containing a specific chemical composition. In these simulations, every coarse-grained (CG) bead represents an entire monomer. The growth function, defined by the chemical behaviour of interacting substances, was determined through repeated random sampling. This approach allowed us to simulate the complex process of radiation-induced polymerisation, enhancing our understanding of the formation of poly(methacrylic acid) hydrogels at a microscopic level; while Monte Carlo simulations have been applied in various contexts of polymerisation, this study's specific approach to modelling the radiation-induced polymerisation of MAA in an aqueous environment, utilising the data obtained by quantum chemistry modelling, with an emphasis on micro-structural growth, has not been extensively explored in existing studies. This understanding is important for advancing the synthesis of these hydrogels, which have potential applications in diverse fields such as materials science and medicine.

10.
Int J Pharm ; 646: 123477, 2023 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-37797783

RESUMO

A compressed pharmaceutical oral solid dosage (OSD) form is a strongly micro-viscoelastic material composite arranged as a network of agglomerated particles due to its constituent powders and their bonding and fractural mechanical properties. An OSD product's Critical Quality Attributes, such as disintegration, drug release (dissolution) profile, and structural strength ("hardness"), are influenced by its micro-scale properties. Ultrasonic evaluation is direct, non-destructive, rapid, and cost-effective. However, for practical process control applications, the simultaneous extraction of the micro-viscoelastic and scattering properties from a tablet's ultrasonic response requires a unique solution to a challenging inverse mathematical wave propagation problem. While the spatial progression of a pulse traveling in a composite medium with known micro-scale properties is a straightforward computational task when its dispersion relation is known, extracting such properties from the experimentally acquired waveforms is often non-trivial. In this work, a novel Machine Learning (ML)-based micro-property extraction technique directly from waveforms, based on Multi-Output Regression models and Neural Networks, is introduced and demonstrated. Synthetic waveforms with a given set of micro-properties of virtual tablets are computationally generated to train, validate, and test the developed ML models for their effectiveness in the inverse problem of recovering specified micro-scale properties. The effectiveness of these ML models is then tested and demonstrated for a set of physical OSD tablets. The micro-viscoelastic and micro-structural properties of physical tablets with known properties have been extracted through experimentally acquired waveforms to exhibit their consistency with the generated ML-based attenuation results.


Assuntos
Tecnologia Farmacêutica , Ultrassom , Tecnologia Farmacêutica/métodos , Composição de Medicamentos/métodos , Comprimidos/química , Pressão
11.
Adv Healthc Mater ; 12(31): e2301518, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37660262

RESUMO

Conventional oral therapy for ulcerative colitis (UC) is associated with premature release or degradation of drugs in the harsh gastrointestinal environment, resulting in reduced therapeutic effectiveness. Consequently, the present study aims to develop a dual-targeted delivery system with a nanoparticle-in-microparticle (nano-in-micro) structure. The prepared Asiatic Acid-loaded delivery system (AA/CDM-BT-ALG) has pH-sensitive properties. Cellular uptake evaluation confirms that nanoparticles exhibit targeted absorption by macrophages and Caco-2 cells through mannose (Man) receptor and biotin-mediated endocytosis, respectively. Therefore, this mechanism effectively enhances intracellular drug concentration. Additionally, the biodistribution study conducted on the gastrointestinal tract of mice indicates that the colon of the microspheres group shows higher fluorescence intensity with longer duration than the other groups. This finding indicates that the microspheres exhibit selective accumulation in areas of colon inflammation. In vivo experiments in colitis mice showed that AA/CDM-BT-ALG significantly alleviates the histopathological characteristics of the colon, reduced neutrophil, and macrophage infiltration, and decreases pro-inflammatory cytokine expression. Furthermore, the effect of AA/CDM-BT-ALG on colitis is validated to be closely related to the TLR4/MyD88/NF-κB signaling pathway. The present findings suggest that the development of a dual-targeted delivery system is accomplished effectively, with the potential to serve as a drug-controlled release system for treating UC.


Assuntos
Colite Ulcerativa , Colite , Nanopartículas , Camundongos , Humanos , Animais , Colite Ulcerativa/metabolismo , Sistemas de Liberação de Medicamentos/métodos , Células CACO-2 , Distribuição Tecidual , Colite/tratamento farmacológico , Colo/metabolismo , Colo/patologia , Nanopartículas/química , Modelos Animais de Doenças
12.
Microsc Res Tech ; 86(12): 1691-1698, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37622437

RESUMO

Microscopic techniques can be applied to solve taxonomic problems in the field of plant systematic and are extremely versatile in nature. This study was focused on the new approaches to visualizing the imaging, tool to cover the micro-structural techniques applied to the pollen study of Amaranthaceae floral biology. In this detailed study, we used light microscopy and scanning electron microscopy to examine the shape and changes in pollen of 16 types of Amaranthaceae plants from the salty arid zone of Riyadh Saudi Arabia. We observed subtle variations among the studied species through meticulous examination of morpho-palynological features such as symmetry, size, shape, pore ornamentation, and exine characteristics. The pollen grains were round and had rough or prickly outer coverings. They had different numbers of tiny pores; some were slightly sunken. These findings were utilized to develop a pollen taxonomy key, facilitating accurate identification and classification of Amaranthaceous species. Our results shed light on the taxonomic significance of pollen morphology for species differentiation within the Amaranthaceae family. Furthermore, this study provides valuable insights into the influence of geographical and ecological factors on pollen diversity and evolution. This study of pollen imaging visualization of Amaranthaceous species contributes to the opportunity for taxonomic evaluation and fill knowledge gaps in studies of Amaranthaceous flora identification using classical microscopic taxonomic tools for their accurate identification. RESEARCH HIGHLIGHTS: The pollen characters of selected Amaranthaceae species were visualized using scanning electron microscopy to observe sculptural wall pattern. The comprehensive Amaranthaceous pollen examination approach allowed us to accurately identify their micromorphology. This high-resolution imaging technique provided detailed insights into the surface structures and ornamentation of the pollen grains.


Assuntos
Amaranthaceae , Pólen , Microscopia Eletrônica de Varredura , Pólen/ultraestrutura , Arábia Saudita
13.
Polymers (Basel) ; 15(15)2023 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-37571185

RESUMO

The significant potential of flexible sensors in various fields such as human health, soft robotics, human-machine interaction, and electronic skin has garnered considerable attention. Capacitive pressure sensor is popular given their mechanical flexibility, high sensitivity, and signal stability. Enhancing the performance of capacitive sensors can be achieved through the utilization of gradient structures and high dielectric constant media. This study introduced a novel dielectric layer, employing the BaTiO3-PDMS material with a gradient micro-cones architecture (GMCA). The capacitive sensor was constructed by incorporating a dielectric layer GMCA, which was fabricated using laser engraved acrylic (PMMA) molds and flexible copper-foil/polyimide-tape electrodes. To examine its functionality, the prepared sensor was subjected to a pressure range of 0-50 KPa. Consequently, this sensor exhibited a remarkable sensitivity of up to 1.69 KPa-1 within the pressure range of 0-50 KPa, while maintaining high pressure-resolution across the entire pressure spectrum. Additionally, the pressure sensor demonstrated a rapid response time of 50 ms, low hysteresis of 0.81%, recovery time of 160 ms, and excellent cycling stability over 1000 cycles. The findings indicated that the GMCA pressure sensor, which utilized a gradient structure and BaTiO3-PDMS material, exhibited notable sensitivity and a broad linear pressure range. These results underscore the adaptability and viability of this technology, thereby facilitating enhanced flexibility in pressure sensors and fostering advancements in laser manufacturing and flexible devices for a wider array of potential applications.

14.
Materials (Basel) ; 16(11)2023 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-37297112

RESUMO

Chloride transport is a vital issue in the research on the durability of alkali-activated materials (AAMs). Nevertheless, due to its miscellaneous types, complex mix proportions, and limitations in testing methods, the reports of different studies are numerous and vary greatly. Therefore, in order to promote the application and development of AAMs in chloride environments, this work systematically reviews the chloride transport behavior and mechanism, solidification of chloride, influencing factors, and test method of chloride transport of AAMs, along with conclusions regarding instructive insights to the chloride transport problem of AAMs in future work.

15.
Materials (Basel) ; 16(11)2023 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-37297300

RESUMO

The advantage of a prefabricated building is its ease of construction. Concrete is one of the essential components of prefabricated buildings. A large amount of waste concrete from prefabricated buildings will be produced during the demolition of construction waste. In this paper, foamed lightweight soil is primarily made of concrete waste, a chemical activator, a foaming agent, and a foam stabilizer. The effect of the foam admixture on the wet bulk density, fluidity, dry density, water absorption, and unconfined compressive strength of the material was investigated. Microstructure and composition were measured by SEM and FTIR. The results demonstrated that the wet bulk density is 912.87 kg/m3, the fluidity is 174 mm, the water absorption is 23.16%, and the strength is 1.53 MPa, which can meet the requirements of light soil for highway embankment. When the foam content ranges from 55% to 70%, the foam proportion is increased and the material's wet bulk density is decreased. Excessive foaming also increases the number of open pores, which reduces water absorption. At a higher foam content, there are fewer slurry components and lower strength. This demonstrates that recycled concrete powder did not participate in the reaction while acting as a skeleton in the cementitious material with a micro-aggregate effect. Slag and fly ash reacted with alkali activators and formed C-N-S(A)-H gels to provide strength. The obtained material is a construction material that can be constructed quickly and reduce post-construction settlement.

16.
Materials (Basel) ; 16(12)2023 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-37374479

RESUMO

As a widely used material in underground engineering, clay-cement slurry grouting is characterized by poor initial anti-seepage and filtration capacity, low strength of the resulting stone body, and a tendency to brittle failure. In this study, a novel type of clay-cement slurry was developed by adding of graphene oxide (GO) as a modifier to ordinary clay-cement slurry. The rheological properties of the improved slurry were studied through laboratory tests, and the effects of varying amounts of GO on the slurry's viscosity, stability, plastic strength, and stone body mechanical properties were analyzed. The results indicated that the viscosity of clay-cement slurry increases by a maximum of 163% with 0.05% GO, resulting in a decrease in the slurry's fluidity. The stability and plastic strength of GO-modified clay-cement slurry were significantly enhanced, with the plastic strength increasing by a 5.62 time with 0.03% GO and a 7.11 time with 0.05% GO at the same curing time. The stone body of the slurry exhibited increased uniaxial compressive strength and shear strength, with maximum increases of 23.94% and 25.27% with 0.05% GO, respectively, indicating a significant optimization effect on the slurry's durability. The micro-mechanism for the effect of GO on the properties of slurry was investigated using scanning electron microscopy (SEM) and a diffraction of X-rays (XRD) test. Moreover, a growth model of the stone body of GO-modified clay-cement slurry was proposed. The results showed that after the GO-modified clay-cement slurry was solidified, a clay-cement agglomerate space skeleton with GO monolayer as the core was formed inside the stone body, and with an increase in GO content from 0.03% to 0.05%, the number of clay particles increased. The clay particles filled the skeleton to form a slurry system architecture, which is the primary reason for the superior performance of GO-modified clay-cement slurry when compared with traditional clay-cement slurry.

17.
Materials (Basel) ; 16(12)2023 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-37374660

RESUMO

The nucleation and the growth of misoriented micro-structure components in single crystals depend on various process parameters and alloy compositions. Therefore, in this study, the influence of different cooling rates on carbon-free, as well as carbon-containing, nickel-based superalloys was investigated. Castings were carried out using the Bridgman and Bridgman-Stockbarger techniques under industrial and laboratory conditions, respectively, to analyze the impact of temperature gradients and withdrawing rates on six alloy compositions. Here, it was confirmed that eutectics could assume a random crystallographic orientation due to homogeneous nucleation in the residual melt. In carbon-containing alloys, eutectics also nucleated at low surface-to-volume ratio carbides due to the accumulation of eutectic-forming elements around the carbide. This mechanism occurred in alloys with high carbon contents and at low cooling rates. Furthermore, micro-stray grains were formed by the closure of residual melt in Chinese-script-shaped carbides. If the carbide structure was open in the growth direction, they could expand into the interdendritic region. Eutectics additionally nucleated on these micro-stray grains and consequently had a different crystallographic orientation compared with the single crystal. In conclusion, this study revealed the process parameters that induced the formation of misoriented micro-structures, which prevented the formation of these solidification defects by optimizing the cooling rate and the alloy composition.

18.
Chemosphere ; 327: 138512, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36972876

RESUMO

Progress toward the high water flux of cellulose acetate butyrate (CAB)-based reverse osmosis (RO) membrane is a bottleneck for desalination and mitigation of fresh water shortage. Here, we develop an "optimization of formulation-induced structure" strategy using acetone (solvent), triethyl phosphate (pore-inducing agent), glycerin and n-propanol (boosters), which achieves a state-of-the-art salt rejection of 97.1% and permeate flux of 8.73 L m-2·h-1, ranking top among CAB-based RO membrane. Compared with reported literatures, it represents high separation performance for different concentrations (20-100 mg L-1) of Rhodamine B and Congo red, different ion types (NaCl and MgCl2), different time (600 min), and resistance to feed pressure changes. The key is the appropriate viscosity of the casting solution (995.52 mPa s), the synergy between the components and additives, contributing to the formation of "jellyfish"-like microscopic pore structure with the lowest surface roughness (Ra = 16.3) and good hydrophilicity. The proposed correlation mechanism between additive-optimized micro-structure and desalination provides a promising prospect for CAB-based RO membrane.


Assuntos
Membranas Artificiais , Purificação da Água , Osmose , Purificação da Água/métodos , Cloreto de Sódio , Butiratos
19.
J Behav Ther Exp Psychiatry ; 79: 101821, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36813416

RESUMO

BACKGROUND AND OBJECTIVES: The current study examines the extent to which mindfulness impacts on operant conditioning processes, and explores the suggestion that mindfulness training serves to make humans more sensitive to the current reinforcement contingencies with which they are presented. In particular, the effect of mindfulness on the micro-structure of human schedule performance was explored. It was expected that mindfulness might impact bout-initiation responding to a greater degree than within-bout responding, premised on the assumption that bout-initiation responses are habitual and not under conscious control, but within-bout responses are goal-directed and conscious. METHODS: Nonclinical participants experienced one of three brief (15min) interventions: focused attention breathing exercise (mindfulness), an unfocused attention breathing exercises, or no intervention. They then responded on a multiple random ratio (RR) random interval (RI) schedule. RESULTS: In the no intervention and unfocused attention groups, overall and within-bout response rates were higher on the RR than the RI schedule, but bout-initiation rates were the same on the two schedules. However, for the mindfulness groups all forms of responding were higher for the RR than the RI schedule. Previous work has noted that habitual, and/or unconscious or fringe-conscious events, are impacted by mindfulness training. LIMITATIONS: A nonclinical sample may limit generality. CONCLUSIONS: The current pattern of results suggests that this is also true in schedule-controlled performance, and offers an insight into the manner in which mindfulness alongside conditioning-based interventions, to bring all responses under conscious control.


Assuntos
Atenção Plena , Humanos , Esquema de Reforço , Reforço Psicológico , Condicionamento Operante/fisiologia , Atenção
20.
BMC Musculoskelet Disord ; 24(1): 133, 2023 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-36803341

RESUMO

BACKGROUND: Femoral neck fractures are serious consequence of osteoporosis (OP), numbers of people are working on the micro-mechanisms of femoral neck fractures. This study aims to investigate the role and weight of microscopic properties on femoral neck maximum load (Lmax), funding the indicator which effects Lmax most. METHODS: A total of 115 patients were recruited from January 2018 to December 2020. Femoral neck samples were collected during the total hip replacement surgery. Femoral neck Lmax, micro-structure, micro-mechanical properties, micro-chemical composition were all measured and analyzed. Multiple linear regression analyses were performed to identify significant factors that affected the femoral neck Lmax. RESULTS: The Lmax, cortical bone mineral density (cBMD), cortical bone thickness (Ct. Th), elastic modulus, hardness and collagen cross-linking ratio were all significantly decreased, whereas other parameters were significantly increased during the progression of OP (P < 0.05). In micro-mechanical properties, elastic modulus has the strongest correlation with Lmax (P < 0.05). The cBMD has the strongest association with Lmax in micro-structure (P < 0.05). In micro-chemical composition, crystal size has the strongest correlation with Lmax (P < 0.05). Multiple linear regression analysis showed that elastic modulus was most strongly related to Lmax (ß = 0.920, P = 0.000). CONCLUSIONS: Compared with other parameters, elastic modulus has the greatest influence on Lmax. Evaluation of microscopic parameters on femoral neck cortical bone can clarify the effects of microscopic properties on Lmax, providing a theoretical basis for the femoral neck OP and fragility fractures.


Assuntos
Fraturas do Colo Femoral , Osteoporose , Humanos , Colo do Fêmur/diagnóstico por imagem , Densidade Óssea , Osteoporose/diagnóstico por imagem , Fraturas do Colo Femoral/diagnóstico por imagem , Fraturas do Colo Femoral/cirurgia , Osso Cortical/diagnóstico por imagem
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