Summary
We propose a surrogate model for two‐scale computational homogenization of elastostatics at finite strains. The macroscopic constitutive law is made numerically available via an explicit ...formulation of the associated macroenergy density. This energy density is constructed by using a neural network architecture that mimics a high‐dimensional model representation. The database for training this network is assembled through solving a set of microscopic boundary value problems with the prescribed macroscopic deformation gradients (input data) and subsequently retrieving the corresponding averaged energies (output data). Therefore, the two‐scale computational procedure for nonlinear elasticity can be broken down into two solvers for microscopic and macroscopic equilibrium equations that work separately in two stages, called the offline and online stages. The finite element method is employed to solve the equilibrium equation at the macroscale. As for microscopic problems, an FFT‐based collocation method is applied in tandem with the Newton‐Raphson iteration and the conjugate‐gradient method. Particularly, we solve the microscopic equilibrium equation in the Lippmann‐Schwinger form without resorting to the reference medium. In this manner, the fixed‐point iteration that might require quite strict numerical stability conditions in the nonlinear regime is avoided. In addition, we derive the projection operator used in the FFT‐based method for homogenization of elasticity at finite strain.
In the present paper, the microwave synthesis of MOF-199 and its application as an electrode modifier for the simultaneous voltammetric determination of paracetamol (PAR) and caffeine (CAF) were ...demonstrated. The obtained materials were characterised by X-ray diffraction, a scanning electron microscope (SEM), nitrogen adsorption/desorption isotherms and thermal gravity. The microwave (MW) synthesis of MOF-199 has been compared to its conventional hydrothermal synthesis. It is found that by using the MW synthesis, MOF-199 can be obtained in a much shorter synthesis time with improved yield and textural properties. The electrode modified by MOF-199 was used in order to develop an electroanalytical method that can be used to simultaneously quantify PAR and CAF. The kinetic parameters of the electrode reaction process were also investigated. This proposed method was successfully employed for the simultaneous detection of PAR and CAF in pharmaceutical formulations using the standard addition method and the obtained results compared with the results determined by means of HPLC were found to be statistically similar.
During mouse postnatal eye development, the embryonic hyaloid vascular network regresses from the vitreous as an adaption for high-acuity vision. This process occurs with precisely controlled timing. ...Here, we show that opsin 5 (OPN5; also known as neuropsin)-dependent retinal light responses regulate vascular development in the postnatal eye. In Opn5-null mice, hyaloid vessels regress precociously. We demonstrate that 380-nm light stimulation via OPN5 and VGAT (the vesicular GABA/glycine transporter) in retinal ganglion cells enhances the activity of inner retinal DAT (also known as SLC6A3; a dopamine reuptake transporter) and thus suppresses vitreal dopamine. In turn, dopamine acts directly on hyaloid vascular endothelial cells to suppress the activity of vascular endothelial growth factor receptor 2 (VEGFR2) and promote hyaloid vessel regression. With OPN5 loss of function, the vitreous dopamine level is elevated and results in premature hyaloid regression. These investigations identify violet light as a developmental timing cue that, via an OPN5-dopamine pathway, regulates optic axis clearance in preparation for visual function.
Photoreceptor-specific ciliopathies often affect a structure that is considered functionally homologous to the ciliary transition zone (TZ) called the connecting cilium (CC). However, it is unclear ...how mutations in certain ciliary genes disrupt the photoreceptor CC without impacting the primary cilia systemically. By applying stochastic optical reconstruction microscopy technology in different genetic models, we show that the CC can be partitioned into two regions: the proximal CC (PCC), which is homologous to the TZ of primary cilia, and the distal CC (DCC), a photoreceptor-specific extension of the ciliary TZ. This specialized distal zone of the CC in photoreceptors is maintained by SPATA7, which interacts with other photoreceptor-specific ciliary proteins such as RPGR and RPGRIP1. The absence of
results in the mislocalization of DCC proteins without affecting the PCC protein complexes. This collapse results in destabilization of the axonemal microtubules, which consequently results in photoreceptor degeneration. These data provide a novel mechanism to explain how genetic disruption of ubiquitously present ciliary proteins exerts tissue-specific ciliopathy phenotypes.
This study aimed to examine the relationship between Vietnamese high school students' violent behaviors and their violence exposure (observing and being victimized by school violence), and attitude, ...and perceived school climate. The results from 496 Vietnamese high school students show that students' acceptance of school violence and their experience of being the victim of school violence have a significant, and direct, positive effect on their violent behaviors at school. In the moderation model, when students' perception of school climate is more positive, the effect of their acceptance of violence on their violent behaviors at school reduces, implying the moderating effect of school climate. The results have practical implications for educators and policy makers to intervene school violence in Vietnam.
The coronavirus disease 2019 (COVID-19) pandemic will have a large impact on the publishing industry. This research aims to investigate the influences of the COVID-19 pandemic situation, utilitarian ...and hedonic motivations on consumer intention to buy books online. It conceptualizes the effects of the COVID-19 pandemic as situational influences, which involve the closure of physical bookstores, health risks associated with visiting such stores, online shopping trend and additional marketing efforts from online bookstores during the pandemic. Data were collected from 275 Vietnamese consumers using an online survey. Multivariate data analysis reveals that the COVID-19 pandemic situation has a positive and significant impact on consumer intention toward online book shopping. Furthermore, while utilitarian motivation exerts a strong effect on consumer intention to purchase books online, the relationship between hedonic motivation and online purchase intention is positive but insignificant. These findings would assist key stakeholders such as publishers and online bookstores to improve the quality of their websites as well as develop their marketing campaigns.
In the present paper, a porous octahedral (ZnO/CuO) composite is synthesized from zinc/copper-based metal-organic framework-199, and its applications in visible-light-driven photocatalytic ...degradation of dyes are demonstrated. The precursors of Zn-BTC, Cu-BTC, and Zn/Cu-BTC (BTC: benzene-1,3,5-tricarboxylate) were synthesized using a microwave-assisted method. Benzene-1,3,5-tricarboxylate acts as a sacrificial template and was removed from the precursors via thermal decomposition to form CuO, ZnO, and ZnO/CuO. ZnO/CuO with a large specific surface area of 32.5 m2·g–1 is composed of porous octahedral particles of 5–10 μm in diameter. Methylene blue (MB) was utilized as the dye model for photocatalytic degradation reactions. The porous octahedral ZnO/CuO exhibits superior visible-light-driven photocatalytic degradation of MB compared with single CuO or ZnO. The kinetic model of photocatalytic degradation was proposed as 1/KL×lnC+C=−krt+1/KL×lnCe+Ce, where KL is the Langmuir equilibrium constant and Ce is the MB concentration at equilibrium. The model significantly fits the kinetic data. In addition, the acquired catalyst manifests excellent photocatalytic degradation for several other dyes including phenol red, methyl orange, and Congo red.
Zinc/cobalt (Zn/Co)-based zeolite imidazole frameworks (ZIFs) with varying Zn/Co molar ratios from 0/10 to 10/0 were synthesized by a microwave-assisted method, and the resulting materials were ...characterized by x-ray diffraction (XRD), nitrogen adsorption–desorption isotherms, scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and atomic absorption spectroscopy (AAS). The microwave-assisted approach required a very short synthesis time as well as yielded (Zn/Co)ZIFs with high specific surface areas (1637.3 m
2
g
−1
). It was found that the introduction of zinc into ZIF-67 enhanced catalytic activity in visible-light region. (Zn/Co)ZIF with a Zn/Co molar ratio of 2/8 manifested an excellent photocatalytic degradation of Congo red (CGR). The kinetic model of photocatalytic degradation was proposed based on adsorption isotherms (Langmuir model) and a unimolecular reaction for the heterogeneous catalysis. Further, the reusability was also addressed.
COVID-19 has become an epidemic affecting all aspects of human life. Vietnam is now encountering the COVID-19 second wave, which puts the mental health of Vietnamese people at risk. Due to the ...adverse psychological effects of the COVID-19 global pandemic on human psychological well-being in these challenging times, the aims of this study are to examine the relationship between self-compassion and psychological well-being and the role of gratitude and COVID-19 stress as a multimediators model in a cross-sectional study. Participants include 509 Vietnamese adults (Mage = 31.71; SD = 7.28 years) recruited through an online survey. A 26-item Self-Compassion Scale was used to measure self-compassion, gratitude was measured by the 6-item Gratitude in the COVID-19, psychological well-being was measured by the World Health Organization Well-Being Index, and the COVID-19 Stress Scale was used to measure stress and fears symptoms caused by the pandemic. The results support 3 main findings: (a) self-compassion has a direct influence on the psychological well-being (effect = 0.50, p < .001, 95% confidence interval CI; 0.43, 0.57), (b) the mediating role of gratitude in this model was significant (effect = 0.07, 95% CI 0.04, 0.10), and (c) the mediating role of COVID-19 stress and fears in this model was also significant (effect = 0.02, 95% CI 0.01, 0.04). The study's results also show that increasing self-compassion and gratitude could help to improve psychological well-being and reduce the influence of COVID-19 stress and fears on the individuals' mental health.
In this letter, we propose a multi-rate caching (MRC) scheme for video offloading in dense device-to-device (D2D) networks. The MRC scheme utilises homogeneous Poisson Point Process model, D2D ...underlay transmission mode, and features of videos encoded into multiple rates (or versions), to derive the cache and spectrum sharing hit probabilities and the cache-based achievable rate. This way, an MRC optimisation problem is formulated for optimal caching probability and encoding rate selection of each video. The MRC optimisation problem further considers the playback resolution and storage resource constraints of the mobile devices to serve the mobile users more efficiently. As a result, the MRC solution gains the highest video offloading playback quality while conserving the bandwidth and caching storage resources of dense D2D networks.
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