Application of extended end composite pile design in pile foundation work

Pre-tensioned, spun, high-strength concrete (PHC) piles are the most commonly used type of pile in South Korea. Approximately 60% of the pile's strength is used in the design bearing capacity, and the rest is simply residing in the ground. Increasing the ground bearing capacity is crucial to reduce waste of the pile strength and to improve efficiency. Extended end (Ext) piles are a new kind of composite pile that can overcome the weakness of PHC piles. This study investigates the behaviour of Ext piles. Through field testing, it is confirmed that the bearing capacity of Ext piles is better than PHC piles by about 35% to 50%. Based on the study findings, the Ext pile design reduces the number of piles by around 38% compared to the PHC pile design through application in a selected construction site. The increased bearing capacity of Ext piles affects both work duration and project cost, which are 25% and 14% decreased, respectively

Laparoscopic Renal Denervation System for Treating Resistant Hypertension: Overcoming Limitations of Catheter-Based Approaches

Goal: In a pivotal clinical trial, the percutaneous catheter-based renal denervation system developed to treat resistant hypertension did not show effectiveness in reducing blood pressure because of its fundamental limitation to ablate deeper nerves present around the renal artery. Methods: We propose a new renal denervation strategy called laparoscopicdenervation system (LDS) based-on laparoscopy procedure to ablate the renal nerves completely but inhibit the thermal arterial damage.The system has flexible electrodes to bend around the arterial wall to ablate nervesThe simulation study using validated in-silico models evaluated the heat distributionon the outer arterial wall,and an acute animal study (swine model) was conducted to demonstrate the feasibility of LDS in vivo. Results: The simulation studyconfirmedthat LDS could localize the heat distributionbetween the electrode and the outer arterial wall. In the animal study, we could maximize nerve denervation by the localizing ablation energy within the renal nerves and achieve nerve denaturationand decrease in neural density by 20.78% (P < 0.001), while maintaining a constant tip temperature of 65 degrees C for the duration of 70 s treatment. The study confirmed intact lumen artery through histological analysis and acute reduction in systolic blood pressure by 9.55 mmHg (p < 0.001) Conclusion: The LDS presented here has potential to effectively and safely ablate the renal nerves, independent of anatomical variation and nerve distribution, to control hypertension in real clinical conditions. Significance: LDS approach is innovative, inventive, and presents a novel technique totreat hypertension.11Yscopu

Sleep Status and the Risk Factor of Drowsy-Related Accidents in Commercial Motor Vehicle Drivers

Background and Objective The purpose of this study was to describe prevalence of sleep problems including obstructive sleep apnea (OSA), insomnia, and sleep insufficiency in commercial motor vehicle (CMV) drivers, and to quantify risk of drowsy-related accidents in CMV drivers. Methods CMV drivers were invited to participate in this study. Participants were asked to complete a questionnaire about sleep habits, sleep disorders, work environments, and experience of drowsy-related accidents. A home sleep test (Watch-PAT 200) was also undertaken to detect OSA. Results Among 110 participants, 89 with eligible data of questionnaires and home sleep tests were included in the analysis. 91.0% of participants had OSA with peripheral arterial tonometry respiratory distress index (pRDI) ≥ 5/h and 23.6% had moderate to severe OSA with pRDI ≥ 15/h. 55.1% perceived that their sleep is insufficient. 52.3% of participants experienced drowsy driving. Drowsy driving-related motor vehicle crashes (MVCs) and near miss MVCs were reported by 9.6% and 37.9% of participants, respectively. Multiple regression analysis showed that increased risk of drowsy driving was associated with perceived sleep insufficiency [odds ratio (OR) = 3.48, 95% confidence interval (CI) 1.26–9.64]. Increased risk of drowsy driving-related near miss MVC was associated with perceived sleep insufficiency (OR = 3.06, 95% CI 1.11–8.44) and continuous driving for more than 4 hours (OR = 3.10, 95% CI 1.00–9.58). Conclusions OSA and perceived sleep insufficiency are prevalent in CMV drivers. Perceived sleep insufficiency and longer continuous driving hours increased risk of drowsy-related accidents

Quasi-graphitic carbon shell-induced Cu confinement promotes electrocatalytic CO2 reduction toward C2+ products

For steady electroconversion to value-added chemical products with high efficiency, electrocatalyst reconstruction during electrochemical reactions is a critical issue in catalyst design strategies. Here, we report a reconstruction-immunized catalyst system in which Cu nanoparticles are protected by a quasi-graphitic C shell. This C shell epitaxially grew on Cu with quasi-graphitic bonding via a gas–solid reaction governed by the CO (g) - CO2 (g) - C (s) equilibrium. The quasi-graphitic C shell-coated Cu was stable during the CO2 reduction reaction and provided a platform for rational material design. C2+ product selectivity could be additionally improved by doping p-block elements. These elements modulated the electronic structure of the Cu surface and its binding properties, which can affect the intermediate binding and CO dimerization barrier. B-modified Cu attained a 68.1% Faradaic efficiency for C2H4 at −0.55 V (vs RHE) and a C2H4 cathodic power conversion efficiency of 44.0%. In the case of N-modified Cu, an improved C2+ selectivity of 82.3% at a partial current density of 329.2 mA/cm2 was acquired. Quasi-graphitic C shells, which enable surface stabilization and inner element doping, can realize stable CO2-to-C2H4 conversion over 180 h and allow practical application of electrocatalysts for renewable energy conversion. © 2021, The Author(s).1

A Solvent-Free Thermosponge Nanoparticle Platform for Efficient Delivery of Labile Proteins

Protein therapeutics have gained attention recently for treatment of a myriad of human diseases due to their high potency and unique mechanisms of action. We present the development of a novel polymeric thermosponge nanoparticle for efficient delivery of labile proteins using a solvent-free polymer thermo-expansion mechanism with clinical potential, capable of effectively delivering a range of therapeutic proteins in a sustained manner with no loss of bioactivity, with improved biological half-lives and efficacy in vivo

Ermin deficiency leads to compromised myelin, inflammatory milieu, and susceptibility to demyelinating insult

Ermin is an actin-binding protein found almost exclusively in the central nervous system (CNS) as a component of myelin sheaths. Although Ermin has been predicted to play a role in the formation and stability of myelin sheaths, this has not been directly examined in vivo. Here, we show that Ermin is essential for myelin sheath integrity and normal saltatory conduction. Loss of Ermin in mice caused de-compacted and fragmented myelin sheaths and led to slower conduction along with progressive neurological deficits. RNA sequencing of the corpus callosum, the largest white matter structure in the CNS, pointed to inflammatory activation in aged Ermin-deficient mice, which was corroborated by increased levels of microgliosis and astrogliosis. The inflammatory milieu and myelin abnormalities were further associated with increased susceptibility to immune-mediated demyelination insult in Ermin knockout mice. Supporting a possible role of Ermin deficiency in inflammatory white matter disorders, a rare inactivating mutation in the ERMN gene was identified in multiple sclerosis patients. Our findings demonstrate a critical role for Ermin in maintaining myelin integrity. Given its near-exclusive expression in myelinating oligodendrocytes, Ermin deficiency represents a compelling “inside-out” model of inflammatory dysmyelination and may offer a new paradigm for the development of myelin stability-targeted therapies

Defect-assisted tunneling in the Resonant Tunneling Diode

Vita.The major goal of this research is to understand the current transport mechanisms of the RTD(Resonant Tunneling Diode). A significant discrepancy exists between the predicted and measured values of the RTD current in the off-resonance region. Theory consistently predicted lower off-resonant currents than are observed. To model this underestimated valley current, defect states are introduced that perturb the conduction band profile. The results of model simulations are compared to measurements on real devices. In this dissertation, the current-voltage characteristics of the resonant tunneling diode (RTD) were based on the Thomas-Fermi model. The dependency on the structural parameters was studied by varying parameters of interest in simulation of model devices. The electrical parameters of the RTD necessary for circuit applications can be controlled by proper selecting of structural parameters. In order to better understand the overestimated peak-to-valley current ratios (PVCR) of double barrier resonant tunneling diodes, a defect-assisted tunneling mechanism through defect states inside the barriers is proposed and analyzed. For simplicity a one-dimensional δ function potential to describe the defect states is used to model defect state. The transmission coefficients are calculated using a transfer matrix method. The shape of the transmission coefficient is broadened and greatly increased in the off-resonance region compared to devices without such defects. The simulation results shows that the increase of the transmission coefficient in the off-resonance energy level contributes to an increase of the valley current and thus a reduction of the PVCR. A strong temperature dependence is observed due to the broadness and enhancement in the off-resonance transmission coefficient. The temperature dependence at a different bias was studied using the Arrhenius plots. Below the peak voltage, the slope of high temperature region is reduced as the bias approaches the peak voltage. Then in the valley region, the slope is reduced with increasing bias. The measured current-voltage characteristics show the same trend as the predicted one..

Defect-assisted tunneling in the Resonant Tunneling Diode

Vita.The major goal of this research is to understand the current transport mechanisms of the RTD(Resonant Tunneling Diode). A significant discrepancy exists between the predicted and measured values of the RTD current in the off-resonance region. Theory consistently predicted lower off-resonant currents than are observed. To model this underestimated valley current, defect states are introduced that perturb the conduction band profile. The results of model simulations are compared to measurements on real devices. In this dissertation, the current-voltage characteristics of the resonant tunneling diode (RTD) were based on the Thomas-Fermi model. The dependency on the structural parameters was studied by varying parameters of interest in simulation of model devices. The electrical parameters of the RTD necessary for circuit applications can be controlled by proper selecting of structural parameters. In order to better understand the overestimated peak-to-valley current ratios (PVCR) of double barrier resonant tunneling diodes, a defect-assisted tunneling mechanism through defect states inside the barriers is proposed and analyzed. For simplicity a one-dimensional δ function potential to describe the defect states is used to model defect state. The transmission coefficients are calculated using a transfer matrix method. The shape of the transmission coefficient is broadened and greatly increased in the off-resonance region compared to devices without such defects. The simulation results shows that the increase of the transmission coefficient in the off-resonance energy level contributes to an increase of the valley current and thus a reduction of the PVCR. A strong temperature dependence is observed due to the broadness and enhancement in the off-resonance transmission coefficient. The temperature dependence at a different bias was studied using the Arrhenius plots. Below the peak voltage, the slope of high temperature region is reduced as the bias approaches the peak voltage. Then in the valley region, the slope is reduced with increasing bias. The measured current-voltage characteristics show the same trend as the predicted one..