Search Results (42)

The scalable synthesis of high-quality single-crystal diamond films remains pivotal for next-generation extreme-performance devices. Iridium substrates offer exceptional promise for heteroepitaxy, yet early-stage growth mechanisms limiting crystal quality are poorly understood. An integrated multiscale investigation combining first-principles DFT calculations, molecular dynamics simulations, and experimental validation is presented to resolve the oriented attachment process governing diamond growth on Ir(100). Robust interfacial bonding at the interface and optimal carbon coverage are revealed to provide thermodynamic driving forces for primary nucleation. A critical angular tolerance enabling defect-free coalescence through crystallographic realignment is identified by molecular dynamics. Concurrent nucleation growth pathways are experimentally confirmed through SEM, AFM, and Raman spectroscopy, where nascent crystallites undergo spontaneous orientational registry to form continuous epitaxial domains. Grain boundary annihilation is observed upon lattice rotation aligning adjacent grains below the critical angle. Crucially, intrinsic atomic steps are generated on the resultant coalesced layer, eliminating conventional etching requirements for homoepitaxial thickening. This work advances fundamental understanding of single-crystal diamond growth mechanisms, facilitating enhanced quality control for semiconductor device manufacturing and quantum applications. Full article

Meditation interventions have important benefits, including potentially helping those with higher attachment anxiety and avoidance enjoy better personal and relational growth. This preregistered and reproducible systematic map sought to identify the extent and scope of experimental evidence investigating the role of mindfulness, loving-kindness, and compassion-based multi-session meditation interventions in (a) moderating the effects of attachment orientations on outcomes over time and/or (b) changing attachment orientations over time. We conducted a systematic map, as the literature on meditation interventions and attachment is nascent. We searched 5 databases, screening 725 studies. We extracted data from four journal articles and one dissertation (five studies in total) which met our inclusion criteria. Four studies examined the effects of meditation interventions on buffering attachment insecurity and one examined attachment security enhancement. All five studies included a mindfulness meditation intervention, and one included a loving-kindness meditation intervention. All studies were conducted in Western cultures. Studies primarily found evidence for interventions benefitting those with higher attachment anxiety, although some evidence emerged for higher attachment avoidance. Our systematic map highlights a critical need for further application of meditation interventions in an attachment and personal growth context, given the promising nature of early work in this area. Full article

The delivery of mesothelial cells by nanofibrous membranes (NFMs) can repair a damaged peritoneal mesothelium and enhance peritoneal healing in patients with chronic renal failure. On the other hand, the orientation of the nanofibers in NFMs may affect cell attachment, proliferation, and the phenotype of mesothelial cells in the nanostructured scaffold. We prepare composite gelatin/chitosan NFMs with aligned or random fiber orientations by electrospinning. We cross-link the nanofibers to maintain the fiber orientation during in vitro cell culture. We then study the cellular response of attached mesothelial cells to fiber orientation in the scaffold. From in vitro cell culture with rat mesothelial cells, the prepared NFMs show high biocompatibility to support cellular growth, regardless of fiber orientation. However, the alignment of electrospun nanofibers in a well-defined geometry can promote cell adhesion and proliferation rates with directional cell organization. The anisotropic arrangement of mesothelial cells in the aligned NFM also coincides with the phenotypic maintenance of the attached mesothelial cells, with biophysical cues provided by the aligned nanofibers. The aligned NFMs may find applications in tissue engineering of a damaged mesothelium layer or in other regenerative therapies where cellular alignment is critical for neo-tissue regeneration. Full article

Myofibers are highly specialized contractile cells of skeletal muscles, and dysregulation of myofiber morphogenesis is emerging as a contributing cause of myopathies and structural birth defects. Myotubes are the myofiber precursors and undergo a dramatic morphological transition into long bipolar myofibers that are attached to tendons on two ends. Similar to axon growth cones, myotube leading edges navigate toward target cells and form cell–cell connections. The process of myotube guidance connects myotubes with the correct tendons, orients myofiber morphology with the overall body plan, and generates a functional musculoskeletal system. Navigational signaling, addition of mass and volume, and identification of target cells are common events in myotube guidance and axon guidance, but surprisingly, the mechanisms regulating these events are not completely overlapping in myotubes and axons. This review summarizes the strategies that have evolved to direct myotube leading edges to predetermined tendon cells and highlights key differences between myotube guidance and axon guidance. The association of myotube guidance pathways with developmental disorders is also discussed. Full article

Three-dimensional (3D) hydrogels provide tissue-like complexities and allow for the spatial orientation of cells, leading to more realistic cellular responses in pathophysiological environments. There is a growing interest in developing multifunctional hydrogels using ternary mixtures for biomedical applications. This study examined the biocompatibility and suitability of human auricular chondrocytes from microtia cultured onto steam-sterilized 3D Chitosan/Gelatin/Poly(Vinyl Alcohol) (CS/Gel/PVA) hydrogels as scaffolds for tissue engineering applications. Hydrogels were prepared in a polymer ratio (1:1:1) through freezing/thawing and freeze-drying and were sterilized by autoclaving. The macrostructure of the resulting hydrogels was investigated by scanning electron microscopy (SEM), showing a heterogeneous macroporous structure with a pore size between 50 and 500 μm. Fourier-transform infrared (FTIR) spectra showed that the three polymers interacted through hydrogen bonding between the amino and hydroxyl moieties. The profile of amino acids present in the gelatin and the hydrogel was determined by ultra-performance liquid chromatography (UPLC), suggesting that the majority of amino acids interacted during the formation of the hydrogel. The cytocompatibility, viability, cell growth and formation of extracellular matrix (ECM) proteins were evaluated to demonstrate the suitability and functionality of the 3D hydrogels for the culture of auricular chondrocytes. The cytocompatibility of the 3D hydrogels was confirmed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, reaching 100% viability after 72 h. Chondrocyte viability showed a high affinity of chondrocytes for the hydrogel after 14 days, using the Live/Dead assay. The chondrocyte attachment onto the 3D hydrogels and the formation of an ECM were observed using SEM. Immunofluorescence confirmed the expression of elastin, aggrecan and type II collagen, three of the main components found in an elastic cartilage extracellular matrix. These results demonstrate the suitability and functionality of a CS/Gel/PVA hydrogel as a 3D support for the auricular chondrocytes culture, suggesting that these hydrogels are a potential biomaterial for cartilage tissue engineering applications, aimed at the regeneration of elastic cartilage. Full article

This study investigated the characteristics of feedback-seeking behavior and the underlying motivational antecedents including the mindsets and achievement goals of Chinese EFL learners. Questionnaire data were collected from 677 learners taking English classes at different levels in China for (1) their beliefs about English learning (a fixed or growth mindset), (2) goal orientation in achievement-related situations (development or demonstration goals), and (3) FSB (whether to seek feedback, by what strategies, and from whom). Results indicated that Chinese EFL learners with a growth mindset or demonstration-approach goals proactively seek feedback through variant strategies (i.e., feedback direct inquiry, indirect inquiry, and monitoring) while those with development-approach goals or a fixed mindset seek feedback by monitoring only due to learners’ different perceptions of the cost and value attached to different strategies. Furthermore, a demonstration approach partially mediated the predictive role of a growth mindset on three FSBs, while the relationships between feedback monitoring and the two mindsets were partially or fully mediated by a development approach. Full article

Single crystalline anatase TiO₂ microspheres with co-exposed {001}/{101} facets were prepared by a facile one-pot hydrothermal method using NaF as a morphology controlling agent. The influences of the NaF amount on the morphology and also on the photocatalytic activity were investigated systematically. The obtained microspheres possessed better morphology when the concentration of NaF was chosen at 0.1 mol/L, and the experimental results indicated that the crystal structure and morphology played important roles on the photocatalytic activity, based on the experimental results it was found that the photocatalytic degradation efficiency of TiO₂ microspheres on Tetracycline hydrochloride could reach 76.4% in 2 h. Finally, a growth mechanism was proposed by investigating the growth process, i.e., a synergistic effect of F ions modified Ostwald ripening and oriented attachment. Full article

Entrepreneurship catalyzes economic growth; it generates jobs, advances the economy and solves global challenges. Hence, it is crucial to understand the factors contributing to entrepreneurship and entrepreneurs’ development. While many studies have investigated intrapersonal factors for entrepreneurial tendencies, the present study focuses on a critical yet often overlooked interpersonal aspect: attachment orientations. Specifically, this article examines the relationship between adult attachment orientations and entrepreneurial tendencies. Three studies across three countries (Israel, the UK, and Singapore) indicated that an anxious attachment orientation in close relationships is negatively associated with enterprising tendencies. In Israel (Study 1) and Singapore (Study 2), avoidant attachment in close relationships was also negatively correlated to such tendencies. Overall, the more people feel secure in close relationships (lower scores on attachment anxiety or avoidance), the higher their enterprising tendencies. Limitations and future research suggestions are discussed. Full article

At present, composite solder pastes are getting a lot of attention, especially composite Sn based solders reinforced by nanoparticles. Indeed, CoSn₃ is a strong nucleating agent of Sn crystal, which has potential application value in the field of electronic packaging. However, there is no reliable synthetic path for CoSn₃ nanoparticles at present. In this article, a chemical synthesis method for CoSn₃ nanoparticles is developed. Here, CoCl₂ and SnCl₂ are reduced by NaHB₄ in triethylene glycol (TEG), dispersed by ultrasonics, and heated to 350 °C in a tube furnace for growth. The CoSn₃ nanoparticles with a diameter of about 150 nm are obtained by heating at 350 °C for 10 min. The CoSn₃ nanoparticles undergo a step reaction in the process of synthesis and go through different stages of merging and annexation during their growth. The crystal growth behavior and the process of orientation change during the nucleation and growth of CoSn₃ nanoparticles are studied, especially the two growth mechanisms, namely OU (orientation unified) and OA (orientation attached). By mixing CoSn₃ nanoparticles with SAC305, we obtain a kind of strengthened composite soldering paste. There are obvious six-fold cyclic twins in the joints made by this soldering paste. Full article

A method of phase-transfer water/toluene synthesis was developed to fabricate mesocrystals of Zeolite Socony Mobil-5 (ZSM-5) that contain both meso-/micropores and nanometer crystallites. The construction of a hierarchical architecture from nanozeolites via oriented attachment growth was achieved by a simple phase-transfer water/toluene synthesis by minimizing classical atom-by-atom crystallization. This opens the way to the cheap, highly efficient engineering of zeolitic morphologies. The physicochemical properties of the crystal were revealed by powder X-ray diffraction (XRD), N₂ physical adsorption, inductively coupled plasma atomic emission spectroscopy (ICP-AES), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ammonia temperature-programmed desorption (NH₃-TPD) and pyridine infrared spectroscopy (Py-IR), indicating that the material has a high specific surface area, mesopore volume and Lewis acid content. The hierarchical ZSM-5 exhibits a prolonged catalytic lifetime in dimethyl ether–methyl ether (DTO) conversion and enhanced selectivity for propylene owing to the enhanced structural properties. The method can be extended to the synthesis of other graded zeolites controlled by the crystallization process and produce crystals comprising traversing mesoporosity and ultrasmall crystallites that are crucial for mass transfer enhancement. Full article

In this study, a CO₂ carbonization method is introduced for the preparation of 1D yttrium oxide powders. Using YCl₃ as the raw material, sodium hydroxide was initially used to completely precipitate Y³⁺ into yttrium hydroxide, and then CO₂ was introduced into the yttrium hydroxide slurry for homogenization-like carbonization to obtain yttrium carbonate precipitation. Then, by studying the effects of carbonization conditions, such as the temperature, CO₂ flow rate, and stirring speed, on the morphology and phases of yttrium carbonate, the temperature was observed to exert a greater effect than the other experimental parameters on the morphology and structure of the carbonized products. Finally, Y₂(CO₃)₃·2H₂O nanoneedles were obtained at optimal conditions. The carbonized crystals of the acicular yttrium carbonate precipitate because of the solution supersaturation and then quickly complete their crystal growth process through the oriented attachment (OA) and Ostwald ripening (OR) mechanisms. After heat treatment, yttrium carbonate retained a good crystal morphology and produced Y₂O₃ nanoneedles with a length of 1–2 μm and a width of 20–30 nm. Full article

Anisotropic ZrO${}_2$ particles with octahedron-, diamond- and plate-like morphologies are successfully synthesized by a facile hydrothermal treatment approach using NaBF${}_4$ as mineralizer. The concentration of mineralizers play a crucial role on the formation of shape-controlled ZrO${}_2$ particles thus affect the particle size. With the increasing concentration of mineralizer, the crystalline sizes of the primary single-crystal and the secondary particle size both increase. With the introduction of NaBF${}_4$, F${}^{-}$ plays an essential role in tuning the crystallinity and size of primary ZrO${}_2$ nanorods along [001] direction. The synergistic effect of F${}^{-}$ and B${}^{3+}$ result in different epitaxial growth rate. And the secondary particles mainly crystallize on the small primary nanoparticles through the oriented attachment mechanism. The as-prepared ZrO${}_2$ particles with different sizes and shapes exhibit different photocatalytic efficiency for the degradation of organic dyes. Under UV irradiation, the highest MB degradation rate of 88% was observed within 60 min for ZrO${}_2$ photocatalyst synthesized with 0.01 mol/L NaBF${}_4$ mineralizer. Full article

Bile acids (BAs) are a group of amphiphilic molecules consisting of a rigid steroid core attached to a hydroxyl group with a varying number, position, and orientation, and a hydrophilic side chain. While BAs act as detergents to solubilize lipophilic nutrients in the small intestine during digestion and absorption, they also act as hormones. Farnesoid X receptor (FXR) is a nuclear receptor that forms a heterodimer with retinoid X receptor α (RXRα), is activated by BAs in the enterohepatic circulation reabsorbed via transporters in the ileum and the colon, and plays a critical role in regulating gene expression involved in cholesterol, BA, and lipid metabolism in the liver. The FXR/RXRα heterodimer also exists in the distal ileum and regulates production of fibroblast growth factor (FGF) 15/FGF19, a hormone traveling via the enterohepatic circulation that activates hepatic FGF receptor 4 (FGFR4)-β-klotho receptor complex and regulates gene expression involved in cholesterol, BA, and lipid metabolism, as well as those regulating cell proliferation. Agonists for FXR and analogs for FGF15/19 are currently recognized as a promising therapeutic target for metabolic syndrome and cholestatic diseases. Full article

The stratigraphic development of foreland basins has mainly been related to surface loading in the adjacent orogens, whereas the control of slab loads on these basins has received much less attention. This has also been the case for interpreting the relationships between the Oligocene to Micoene evolution of the European Alps and the North Alpine foreland basin or Molasse basin. In this trough, periods of rapid subsidence have generally been considered as a response to the growth of the Alpine topography, and thus to the construction of larger surface loads. However, such views conflict with observations where the surface growth in the Alps has been partly decoupled from the subsidence history in the basin. In addition, surface loads alone are not capable of explaining the contrasts in the stratigraphic development particularly between its central and eastern portions. Here, we present an alternative view on the evolution of the Molasse basin. We focus on the time interval between c. 30 and 15 Ma and relate the basin-scale development of this trough to the subduction processes, and thus to the development of slab loads beneath the European Alps. At 30 Ma, the western and central portions of this basin experienced a change from deep marine underfilled (Flysch stage) to overfilled terrestrial conditions (Molasse stage). During this time, however, a deep marine Flysch-type environment prevailed in the eastern part of the basin. This was also the final sedimentary sink as sediment was routed along the topographic axis from the western/central to the eastern part of this trough. We interpret the change from basin underfill to overfill in the western and central basin as a response to oceanic lithosphere slab-breakoff beneath the Central and Western Alps. This is considered to have resulted in a growth of the Alpine topography in these portions of the Alps, an increase in surface erosion and an augmentation in sediment supply to the basin, and thus in the observed change from basin underfill to overfill. In the eastern part of the basin, however, underfilled Flysch-type conditions prevailed until 20 Ma, and subsidence rates were higher than in the western and central parts. We interpret that high subsidence rates in the eastern Molasse occurred in response to slab loads beneath the Eastern Alps, where the subducted oceanic slab remained attached to the European plate and downwarped the plate in the East. Accordingly, in the central and western parts, the growth of the Alpine topography, the increase in sediment flux and the change from basin underfill to overfill most likely reflect the response to slab delamination beneath the Central Alps. In contrast, in the eastern part, the possibly subdued topography in the Eastern Alps, the low sediment flux and the maintenance of a deep marine Flysch-type basin records a situation where the oceanic slab was still attached to the European plate. The situation changed at 20 Ma, when the eastern part of the basin chronicled a change from deep marine (underfilled) to shallow marine and then terrestrial (overfilled conditions). During the same time, subsidence rates in the eastern basin decreased, deformation at the Alpine front came to a halt and sediment supply to the basin increased possibly in response to a growth of the topography in the Eastern Alps. This was also the time when the sediment routing in the basin axis changed from an east-directed sediment dispersal prior to 20 Ma, to a west-oriented sediment transport thereafter and thus to the opposite direction. We relate these changes to the occurrence of oceanic slab breakoff beneath the Eastern Alps, which most likely resulted in a rebound of the plate, a growth of the topography in the Eastern Alps and a larger sediment flux to the eastern portion of the basin. Beneath the Central and Western Alps, however, the continental lithosphere slab remained attached to the European plate, thereby resulting in a continued downwarping of the plate in its central and western portions. This plate downwarping beneath the central and western Molasse together with the rebound of the foreland plate in the East possibly explains the inversion of the drainage direction. We thus propose that slab loads beneath the Alps were presumably the most important drivers for the development of the Molasse basin at the basin scale. Full article

Transparent, flexible, biaxially oriented polyethylene terephthalate (PET) sheets were modified by bioactive polymer-fibronectin top layers for the attachment of cells and growth of muscle fibers. Towards this end, PET sheets were grafted with 4-(dimethylamino)phenyl (DMA) groups from the in situ generated diazonium cation precursor. The arylated sheets served as macro-hydrogen donors for benzophenone and the growth of poly(2-hydroxy ethyl methacrylate) (PHEMA) top layer by surface-confined free radical photopolymerization. The PET-PHEMA sheets were further grafted with fibronectin (FBN) through the 1,1-carbonyldiimidazole coupling procedure. The bioactive PET-PHEMA-I-FBN was then employed as a platform for the attachment, proliferation and differentiation of eukaryotic cells which after a few days gave remarkable muscle fibers, of ~120 µm length and ~45 µm thickness. We demonstrate that PET-PHEMA yields a fast growth of cells followed by muscle fibers of excellent levels of differentiation compared to pristine PET or standard microscope glass slides. The positive effect is exacerbated by crosslinking PHEMA chains with ethylene glycol dimethacrylate at initial HEMA/EGDA concentration ratio = 9/1. This works conclusively shows that in situ generated diazonium salts provide aryl layers for the efficient UV-induced grafting of biocompatible coating that beneficially serve as platform for cell attachment and growth of muscle fibers. Full article