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The present study was conducted to investigate changes in the thermal conductivity of petroleum pitch-based carbon molded bodies prepared by anisotropic (uniaxial) molding under different molding pressures. The carbon molded bodies were prepared using needle coke and petroleum-based binder pitch polymers (softening point: 150 ℃). Green blocks prepared under high molding pressure showed a higher particle orientation value up to 16.4 μm. Graphite blocks, prepared by graphitizing the green blocks at 2800 ℃ showed a similar trend. The pores in the carbon molded body were filled with low boiling point substances, generated by the thermal treatment of the binder pitch polymer or air that could not be discharged during the molding procedure. Therefore, when phonons encountered a pore, phonon scattering, rather than phonon transport, occurred, and thus the heat transport from the hot zone to a cold zone became slow. As a result, although the particle orientation was a little higher in the B_10-G sample than in the B_20-G sample (in the error range), the thermal conductivity was higher in the B_20-G sample, which may be because the B_10-G sample had a higher porosity than the B_20-G sample.

The graphite block as a phase change materials (PCMs) was manufactured by graphitization of a carbon block. Carbon blocks were prepared by filler (cokes or graphite) and binder (pitch). The binder-coated filler was thermally treated for carbonization. The gases generated from the evaporation of low molecular weight components in the binder pitch during the carbonization process were not released to the outside. Consequently, porosity and volume expansion were increased in artificial graphite, and thereby the thermal conductivity decreased. In this study, to prevent the decrease of thermal conductivity in the artificial graphite due to the disadvantages of binder pitch, the carbon block was prepared by the addition of carbon black, which can absorb low molecular weight compounds and release the generated gas. The properties of the prepared carbon blocks were analyzed by SEM, TGA, and thermal conductivity. The addition of carbon black (CB) decreased the porosity and volume expansion of the carbon blocks by 38.3% and 65.9%, respectively, and increased the thermal conductivity by 57.1%. The CB absorbed the low molecular weight compounds of binder pitch and induced the release of generated gases during the carbonization process to decrease porosity, and the thermal conductivity of the carbon block increased.

Human pluripotent stem cells (hPSCs) are capable of unlimited proliferation and can undergo differentiation to give rise to cells and tissues of the three primary germ layers. While directing lineage selection of hPSCs has been an active area of research, improving the efficiency of differentiation remains an important objective. In this study, we describe a two-compartment microfluidic device for co-cultivation of adult human hepatocytes and stem cells. Both cell types were cultured in a 3D or spheroid format. Adult hepatocytes remained highly functional in the microfluidic device over the course of 4 weeks and served as a source of instructive paracrine cues to drive hepatic differentiation of stem cells cultured in the neighboring compartment. The differentiation of stem cells was more pronounced in microfluidic co-cultures compared to a standard hepatic differentiation protocol. In addition to improving stem cell differentiation outcomes, the microfluidic co-culture system described here may be used for parsing signals and mechanisms controlling hepatic cell fate.

Purpose The criteria for discontinuing antiepileptic drugs (AEDs) in children with well-controlled epilepsy remain unclear. This study sought to identify the recurrence rate of epilepsy after the discontinuation of AEDs and the risk factors associated with recurrence. Methods We retrospectively reviewed the records of 441 children who discontinued AEDs at our department of pediatrics from August 2007 to July 2017. AED tapering was performed in patients who were seizure-free for more than 2 years after taking AEDs, and patients were monitored for 1 year after the discontinuation of AEDs. Results We found that 87 patients (87/441, 19.7%) experienced seizure recurrence within 1 year after the discontinuation of AEDs. Among them, 38 patients (38/87, 43.7%) experienced recurrence during AED tapering. The recurrence of seizures was related to the patient’s age at AED onset and when seizures were controlled, a history of seizure recurrence after previous discontinuation of AEDs or a seizure episode during AED administration, and no improvement of electroencephalographic (EEG) findings. Conclusion The recurrence rate within 1 year after the discontinuation of AEDs was almost 20%, and nearly half of the recurrences took place during the tapering period. We recommend caution when considering whether to discontinue AEDs in patients with a history of seizure recurrence after AED discontinuation, a seizure episode during AED administration, or no (or slight) improvement of EEG findings.