A solution-based process was investigated for synthesizing cubic Li7La3Zr2O12 (LLZO), which is known to exhibit the unprecedented combination of fast ionic conductivity, and stability in air and ...against Li. Sol-gel chemistry was developed to prepare solid metal-oxide networks consisting of 10 nm cross-links that formed the cubic LLZO phase at 600 ° C. Sol-gel LLZO powders were sintered into 96% dense pellets using an induction hot press that applied pressure while heating. After sintering, the average LLZO grain size was 260 nm, which is 13 times smaller compared to LLZO prepared using a solid-state technique. The total ionic conductivity was 0.4 mS cm−1 at 298 K, which is the same as solid-state synthesized LLZO. Interestingly, despite the same room temperature conductivity, the sol-gel LLZO total activation energy is 0.41 eV, which 1.6 times higher than that observed in solid-state LLZO (0.26 eV). We believe the nano-scale grain boundaries give rise to unique transport phenomena that are more sensitive to temperature when compared to the conventional solid-state LLZO.
Land available for energy production is limited in cities owing to high population density. To reach the net zero goal, cities contributing 70% of overall greenhouse gas emissions need to ...dramatically reduce emissions and increase self-sufficiency in energy production. Environmental infrastructures such as sewage treatment and incineration plants can be used as energy production facilities in cities. This study attempted to examine the effect of using environmental infrastructure such as energy production facilities to contribute toward the carbon neutrality goal through urban energy systems. In particular, since the facilities are suitable for hydrogen supply in cities, the analysis was conducted focusing on the possibility of hydrogen production. First, the current status of energy supply and demand, and additional energy production potential in sewage treatment and incineration plants in Seoul, were analyzed. Then, the role of these environmental infrastructures toward energy self-sufficiency in the urban system was examined. This study confirmed that the facilities can contribute to the city’s energy self-sufficiency and the achievement of its net-zero goal.
This study investigates the morphology, microstructure, compressive behavior, biocorrosion properties, and cytocompatibility of magnesium (Mg)-aluminum (Al) alloy (AE42) scaffolds for their potential ...use in biodegradable biomedical applications. Mg alloy scaffolds were successfully synthesized via a camphene-based freeze-casting process with precisely controlled heat treatment. The average porosity was approximately 52% and the median pore diameter was ∼13 μm. Salient deformation mechanisms were identified using acoustic emission (AE) signals and adaptive sequential k-means (ASK) analysis. Twinning, dislocation slip, strut bending, and collapse were dominant during compressive deformation. Nonetheless, the overall compressive behavior and deformation mechanisms were similar to those of bulk Mg based on ASK analysis. The corrosion potential of the Mg alloy scaffold (-1.44 V) was slightly higher than that of bulk AE42 (-1.60 V), but the corrosion rate of the Mg alloy scaffold was faster than that of bulk AE42 due to the enhanced surface area of the Mg alloy scaffold. As a result of cytocompatibility evaluation following ISO10993-5, the concentration of the Mg alloy scaffold extract reducing cell growth rate to 50% (IC50) was 10.7%, which is higher (less toxic) than 5%, suggesting no severe inflammation by implantation into muscle.
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•AE42 foam was successfully synthesized via a camphene-based freeze-casting process.•The foam has open-connected, a few tens to hundreds micrometer pores (porosity: 52%).•The foam has quite similar overall deformation behavior to that of a bulk Mg alloy.•The foam has higher corrosion rate than bulk sample due to its enhanced surface area.•Cytotoxicity of the extract was lower than that causing severe inflammation in muscle.
In this study, we prepared and characterized Nb-doped Li
7
La
3
Zr
2−
x
O
12
(LLZNO) powder and pellets with a cubic garnet structure by using a modified sol-gel synthesis and hot pressing. LLZNO ...powder with a very small grain size and cubic structure without secondary phases could be obtained by using a synthesis method in which Li and La sources in a propanol solvent were mixed together with Zr and Nb sources in 2-methoxy ethanol. A pure cubic phase LLZNO pellet could be fabricated from the prepared LLZNO and an additional 6-wt% of Li
2
CO
3
powder by hot pressing at 1050 °C and 15.8 MPa. The hot-pressed LLZNO pellet with a relative density of 99% exhibited a very dense surface morphology. The total Li ionic conductivity of the hot-pressed LLZNO was 7.4×10
−4
S/cm at room temperature, which is very high level compared to other reported values. The activation energy for ionic conduction was estimated to be 0.40 eV.
Over six billion doses of Coronavirus Disease 2019 (COVID-19) vaccines have been administered worldwide. Amidst the global COVID-19 vaccination campaign, vaccine-related side effects are of ongoing ...concern and investigation. According to the Centers for Disease Control and Prevention (CDC) and the United States Department of Health and Human Services, three main conditions in adults have surfaced in association with receiving the COVID-19 vaccines. These include thrombosis with thrombocytopenia syndrome (TTS), a rare syndrome involving venous or arterial thrombosis and thrombocytopenia, Guillain-Barre syndrome (GBS), and myocarditis. While a number of GBS cases in adults have been published, to our knowledge, only one pediatric case of COVID-19 vaccine-related GBS has been reported. Herein we describe a case of sensory predominant GBS following the Pfizer-BioNTech COVID-19 vaccine in a 16-year-old female presenting with bilaterally ascending upper and lower extremity numbness and paresthesia.
Since the emergence of SARS-CoV-2, several studies have been published describing neuromuscular manifestations of the disease, as well as management of pre-existing pediatric neuromuscular disorders ...during the COVID-19 pandemic. These disorders include muscular dystrophies, myasthenic syndromes, peripheral nerve disorders, and spinal muscular atrophy. Such patients are a vulnerable population due to frequent complications such as scoliosis, cardiomyopathy, and restrictive lung disease that put them at risk of severe complications of COVID-19. In this review, neuromuscular manifestations of COVID-19 in children and the management of pre-existing pediatric neuromuscular disorders during the COVID-19 pandemic are discussed. We also review strategies to alleviate pandemic-associated disruptions in clinical care and research, including the emerging role of telemedicine and telerehabilitation to address the continued special needs of these patients.
Background: Superior vena cava (SVC) syndrome may result from extravascular compression or intravascular obstruction such as thrombosis. Recurrent venous thrombosis is typically associated with a ...hypercoagulable state such as malignancy, and inheritable or acquired coagulopathy. Sarcoidosis is a derangement of the immune system, and it has been associated with malignant diseases and hypercoagulation. The association of pancreatic cancer and sarcoidosis with SVC syndrome has not been reported previously. Here, we present a case of recurrent venous thrombosis causing SVC syndrome in a patient with pancreatic ductal adenocarcinoma and underlying thoracic sarcoidosis. Methods: The patient’s electronic health record was retrospectively analyzed. Results: A 66-year-old woman with pancreatic adenocarcinoma was treated with neoadjuvant chemotherapy followed by Whipple procedure, before developing tumor recurrence in the liver. Her treatment course was complicated with repeated incidents of venous thrombosis in the presence of a central venous catheter leading to recurrent SVC syndrome, which resolved with anti-coagulation. Conclusions: This case raises a plausible inter-relationship between sarcoidosis, pancreatic cancer, and hypercoagulable state. We suggest that patients with multiple risk factors for developing venous thrombosis should be carefully monitored for any thrombotic event, and they may benefit from prophylactic anti-coagulation.
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