Soil-Pile Interaction Analysis using FE-BE Coupling in Frequency Domain

In this study, a numerical method for soil-pile interaction problems in multi-layered half-plane is developed in frequency domain using FE-BE coupling technique. The soil-pile interaction system is divided into two parts, so-called near field and far field. In the near field, beam elements are used for modeling pile and plane-strain finite elements for surrounding soil media. Also, a superstructure is considered as a lumped mass on a pile. In the far field, layered soil media is modeled by boundary element formulation using the dynamic fundamental solution. Then, these two fields are assembled using FE-BE coupling technique. This coupled numerical method automatically satisfies the radiation conditions because the far field boundary element formulation can handle the radiation conditions in a half plane. Additionally, the difference of relative displacement at the interface between soil and pile is considered by applying interface spring elements. In order to verify the proposed method for soil-pile interaction system, the dynamic responses of a pile in a multi-layered half-plane are performed and the numerical results are compared with the measured values from experiments. It is shown that the developed method can be an efficient numerical tool to solve the dynamic response of a pile buried in a multi-layered half plane

How Korean K-12 Educators Adapted to Online Teaching and Promoted Digital Equity During COVID-19: A Mixed-Method Study on Practices and Perceptions

The abrupt transitions to online teaching during COVID-19 have exacerbated educational discrepancies worldwide. South Korean schools faced similar challenges primarily due to the insufficient infrastructure and pedagogical guidelines for online teaching. This mixed-method case study investigated how Korean K-12 teachers and administrators converted to online teaching and addressed related digital equity issues during their first semester of online teaching in response to the pandemic. Interviews, as well as survey responses at the beginning and end of the semester, were analyzed through Activity Theory (AT) and Technological Pedagogical Content Knowledge (TPACK) frameworks. The study's key insights were that the digital equity issue is related to quality teaching issues beyond infrastructural problems and that teachers took various strategies to maximize the effectiveness of their blended teaching. We aim to shed light on supporting equitable online learning and sustaining positive changes in the post-COVID era

The Fate of Tau Aggregates Between Clearance and Transmission

Neuronal accumulation of mis-folded tau is the pathological hallmark of multiple neurodegenerative disorders, including Alzheimer’s disease. Distinct from amyloid plaques, which appear simultaneously throughout the brain, tau pathology develops first in a specific brain region and then propagates to neuroanatomically connected brain regions, exacerbating the disease. Due to the implication in disease progression, prevention of tau transmission is recognized as an important therapeutic strategy that can halt disease progression in the brain. Recently, accumulating studies have demonstrated diverse cellular mechanisms associated with cell-to-cell transmission of tau. Once transmitted, mis-folded tau species act as a prion-like seed for native tau aggregation in the recipient neuron. In this review, we summarize the diverse cellular mechanisms associated with the secretion and uptake of tau, and highlight tau-trafficking receptors, which mediate tau clearance or cell-to-cell tau transmission

Factors affecting the long-term outcomes of idiopathic membranous nephropathy

Abstract Background We attempted to describe the clinical features and determine the factors associated with renal survival in idiopathic membranous nephropathy (iMN) patients with nephrotic syndrome (NS) and to determine the factors associated with spontaneous complete remission (sCR) and progression to NS in iMN patients with subnephrotic proteinuria. Methods This retrospective study involved 166 iMN patients with NS and 65 patients with subnephrotic proteinuria. The primary end point was a doubling of serum creatinine or initiation of dialysis. In patients with subnephrotic proteinuria, we determined the factors associated with sCR and factors associated with progression to NS. Results Remission of NS was achieved in 125 out of 166 patients (75.3%). Of those who reached remission, 26 patients (20.8%) experienced relapse that was followed by second remission. The relapse or persistence of proteinuria was associated with the primary end points (hazard ratio [HR] = 12.40, P = 0.037, HR = 173, P < 0.001, respectively). In patients with subnephrotic proteinuria, sCR occurred in 35.4% of the patients. The patients with sCR had lower proteinuria and serum creatinine levels and higher serum albumin concentrations at baseline. The serum albumin level at diagnosis was a prognostic factor for progression to NS (Odds ratio [OR] = 0.015, P < 0.001). Conclusions The occurrence of relapse or persistence of proteinuria had negative effects on renal survival in iMN patients with NS, and low serum albumin levels at baseline were associated with non-achievement of sCR and progression to NS

Bioconversion of CO to formate by artificially designed carbon monoxide:formate oxidoreductase in hyperthermophilic archaea

Ferredoxin-dependent metabolic engineering of electron transfer circuits has been developed to enhance redox efficiency in the field of synthetic biology, e.g., for hydrogen production and for reduction of flavoproteins or NAD(P)+. Here, we present the bioconversion of carbon monoxide (CO) gas to formate via a synthetic CO:formate oxidoreductase (CFOR), designed as an enzyme complex for direct electron transfer between non-interacting CO dehydrogenase and formate dehydrogenase using an electron-transferring Fe-S fusion protein. The CFOR-introduced Thermococcus onnurineus mutant strains showed CO-dependent formate production in vivo and in vitro. The maximum formate production rate from purified CFOR complex and specific formate productivity from the bioreactor were 2.2????????0.2 ??mol/mg/min and 73.1????????29.0 mmol/g-cells/h, respectively. The CO-dependent CO2 reduction/formate production activity of synthetic CFOR was confirmed, indicating that direct electron transfer between two unrelated dehydrogenases was feasible via mediation of the FeS-FeS fusion protein

Embedding Covalency into Metal Catalysts for Efficient Electrochemical Conversion of CO_2

CO_2 conversion is an essential technology to develop a sustainable carbon economy for the present and the future. Many studies have focused extensively on the electrochemical conversion of CO_2 into various useful chemicals. However, there is not yet a solution of sufficiently high enough efficiency and stability to demonstrate practical applicability. In this work, we use first-principles-based high-throughput screening to propose silver-based catalysts for efficient electrochemical reduction of CO_2 to CO while decreasing the overpotential by 0.4–0.5 V. We discovered the covalency-aided electrochemical reaction (CAER) mechanism in which p-block dopants have a major effect on the modulating reaction energetics by imposing partial covalency into the metal catalysts, thereby enhancing their catalytic activity well beyond modulations arising from d-block dopants. In particular, sulfur or arsenic doping can effectively minimize the overpotential with good structural and electrochemical stability. We expect this work to provide useful insights to guide the development of a feasible strategy to overcome the limitations of current technology for electrochemical CO_2 conversion

The Effect of Clonidine Pretreatment on Epidural Resiniferatoxin in a Neuropathic Pain Rat Model

Resiniferatoxin (RTX) is an ultrapotent synthetic TRPV1 (transient receptor potential vanilloid subtype 1) agonist with significant initial transient hyperalgesia followed by a prolonged analgesic effect in response to thermal stimulus. Using a rat model of neuropathic pain, we evaluated the effect of pretreatment with clonidine－which has been shown to relieve intradermal capsaicin-induced hyperalgesia－on the initial hyperalgesic response and the thermal analgesic property of RTX. Thirty-six male rats were divided into 6 treatment groups (n＝6 each):RTX 500ng, RTX 1μg, clonidine 20μg (Cl), Cl＋RTX 500ng, Cl＋RTX 1μg, or normal saline 20μL (control). We evaluated the short-term (180min) and long-term (20 days) analgesic effects of RTX after thermal stimulation and mechanical stimulation. RTX had significant initial transient hyperalgesia followed by a prolonged analgesic effect in response to the thermal stimulus, but the RTX 500ng and RTX 1μg groups showed no initial short-term thermal hyperalgesic responses when pretreated with clonidine. The Cl＋RTX 1μg ratsʼ behavior scores indicated that they were more calm and comfortable compared to the RTX 1μg rats. Even though we cannot precisely confirm that pretreatment with clonidine potentiates or adds to the analgesic effect of RTX, clonidine pretreatment with epidural RTX eliminated the initial RTX-associated hyperalgesic response and systemic toxicity in this neuropathic pain rat model

A Split-Gate Positive Feedback Device With an Integrate-and-Fire Capability for a High-Density Low-Power Neuron Circuit

Hardware-based spiking neural networks (SNNs) to mimic biological neurons have been reported. However, conventional neuron circuits in SNNs have a large area and high power consumption. In this work, a split-gate floating-body positive feedback (PF) device with a charge trapping capability is proposed as a new neuron device that imitates the integrate-and-fire function. Because of the PF characteristic, the subthreshold swing (SS) of the device is less than 0.04 mV/dec. The super-steep SS of the device leads to a low energy consumption of ∼0.25 pJ/spike for a neuron circuit (PF neuron) with the PF device, which is ∼100 times smaller than that of a conventional neuron circuit. The charge storage properties of the device mimic the integrate function of biological neurons without a large membrane capacitor, reducing the PF neuron area by about 17 times compared to that of a conventional neuron. We demonstrate the successful operation of a dense multiple PF neuron system with reset and lateral inhibition using a common self-controller in a neuron layer through simulation. With the multiple PF neuron system and the synapse array, on-line unsupervised pattern learning and recognition are successfully performed to demonstrate the feasibility of our PF device in a neural network

Altered renal sodium transporter expression in an animal model of type 2 diabetes mellitus

Hemodynamic factors play an important role in the development and/or progression of diabetic nephropathy. We hypothesized that renal sodium transporter dysregulation might contribute to the hemodynamic alterations in diabetic nephropathy. Otsuka Long Evans Tokushima Fatty (OLETF) rats were used as an animal model for type 2 diabetes. Long Evans Tokushima (LETO) rats were used as controls. Renal sodium transporter regulation was investigated by semiquantitative immunoblotting and immunohistochemistry of the kidneys of 40-week-old animals. The mean serum glucose level in OLETF rats was increased to 235+/-25 mg/dL at 25 weeks, and the hyperglycemia continued up to the end of 40 weeks. Urine protein/ creatinine ratios were 10 times higher in OLETF rats than in LETO rats. At 40th week, the abundance of the epithelial sodium channel (ENaC) beta-subunit was increased in OLETF rats, but the abundance of the ENaC gamma-subunit was decreased. No significant differences were observed in the ENaC alpha-subunit or other major sodium transporters. Immunohistochemistry for the ENaC beta-subunit showed increased immunoreactivity in OLETF rats, whereas the ENaC gamma-subunit showed reduced immunoreactivity in these rats. In OLETF rats, ENaC beta-subunit upregulation and ENaC gamma-subunit downregulation after the development of diabetic nephropathy may reflect an abnormal sodium balance