The influence of firing profile and additives on the PTCR effect and microstructure of BaTiO3 ceramics

Nonstoichiometric BaTiO₃ PTCR type materials are investigated with various amounts of MnO₂, Sb₂O₃ and MgO dopants. Specimens fired with a nonisothermal rate-controlled sintering profile exhibit a rather fine and uniform microstructure as compared to those processed by conventional sintering techniques. The temperature at which the resistivity anomaly begins is observed to decrease with Sb₂O₃ and MgO contents. The Curie point of BaTiO₃-based ceramics can be altered by addition of Sb₂O₃, and the dielectric peak is maintained by the presence of MgO additive. Magnesium ions act as acceptors in the BaTiO₂ lattice, while antimony ions as donors. The presence of magnesium compensates some of the antimony, hence the doped-BaTiO₃ seminonductive region is pushed to higher contents.     

Photothermal nanoblade for large cargo delivery into mammalian cells

It is difficult to achieve controlled cutting of elastic, mechanically fragile, and rapidly resealing mammalian cell membranes. Here, we report a photothermal nanoblade that utilizes a metallic nanostructure to harvest short laser pulse energy and convert it into a highly localized explosive vapor bubble, which rapidly punctures a lightly contacting cell membrane via high-speed fluidic flows and induced transient shear stress. The cavitation bubble pattern is controlled by the metallic structure configuration and laser pulse duration and energy. Integration of the metallic nanostructure with a micropipet, the nanoblade generates a micrometer-sized membrane access port for delivering highly concentrated cargo (5 × 10(8) live bacteria/mL) with high efficiency (46%) and cell viability (>90%) into mammalian cells. Additional biologic and inanimate cargo over 3-orders of magnitude in size including DNA, RNA, 200 nm polystyrene beads, to 2 μm bacteria have also been delivered into multiple mammalian cell types. Overall, the photothermal nanoblade is a new approach for delivering difficult cargo into mammalian cells.     

Targeting PSEN1 by lnc-CYP3A43-2/miR-29b-2-5p to Reduce β Amyloid Plaque Formation and Improve Cognition Function

Presenilin-1 (PSEN1) is a crucial subunit within the γ-secretase complex and regulates β-amyloid (Aβ) production. Accumulated evidence indicates that n-butylidenephthalide (BP) acts effectively to reduce Aβ levels in neuronal cells that are derived from trisomy 21 (Ts21) induced pluripotent stem cells (iPSCs). However, the mechanism underlying this effect remains unclear. This article aims to investigate the possible mechanisms through which BP ameliorates the development of Alzheimer’s disease (AD) and verify the effectiveness of BP through animal experiments. Results from RNA microarray analysis showed that BP treatment in Ts21 iPSC-derived neuronal cells reduced long noncoding RNA (lncRNA) CYP3A43-2 levels and increased microRNA (miR)-29b-2-5p levels. Bioinformatics tool prediction analysis, biotin-labeled miR-29b-2-5p pull-down assay, and dual-luciferase reporter assay confirmed a direct negative regulatory effect for miRNA29b-2-5p on lnc-RNA-CYP3A43-2 and PSEN1. Moreover, BP administration improved short-term memory and significantly reduced Aβ accumulation in the hippocampus and cortex of 3xTg-AD mice but failed in miR-29b-2-5p mutant mice generated by CRISP/Cas9 technology. In addition, analysis of brain samples from patients with AD showed a decrease in microRNA-29b-2-5p expression in the frontal cortex region. Our results provide evidence that the LncCYP3A43-2/miR29-2-5p/PSEN1 network might be involved in the molecular mechanisms underlying BP-induced Aβ reduction.     

The application of neural networks in self-tuning constant force control

The constant force control gradually becomes an important technique of modern manufacturing processes. For example, the constant turning or cutting force is a useful approach for increasing the metal removal rate and increasing the tool life. The variation of machining condition may cause the robustness of a classical control theory (PID) to become ineffective, even make a control system unstable. The pole placement self-tuning control (PSTC) theory with a recursive least square parameters estimator is proposed to adapt the environmental variety. Unfortunately, the adaptability and the robustness of a self-tuning control system cannot be maintained in good condition simultaneously all the time. In this paper, a self-tuning controller equips with a neural network parameter classifier in conjunction with a least square estimator is developed to improve the adaptability and the robustness in suffering the obvious environmental variation. In order to verify the applicability of this control method, a prototype system is designed and constructed to resemble the feed rate mechanism of lathe. The dynamic responses of this force control system with different estimators are compared based upon the experimental data. The contact force is measured from a load cell and adjusted by regulating the feed rate.     

Enhancing distributed event predicate detection algorithms

Recently published algorithms for matching concurrent sets of events have the problem of unbounded message queue growth if events arrive in an undesirable order. This paper presents some algorithms that mitigate this problem by examining events waiting to be processed and removing those that cannot be part of a concurrent set     

Emergency postcoital contraception

Pancreatitis may be acute or chronic, mild or severe. Acute necrotizing pancreatitis remains the most serious form of acute pancreatitis and accounts for the majority of complications. Although there is an established nomenclature for pancreatitis and pancreatic fluid collections, such as pancreatic pseudocysts, it is not widely understood or recognized by gastroenterologists. Because the management options for the treatment of pancreatic fluid collections continues to evolve with an increased use of endoscopic therapy, gastroenterologists will be increasingly called on to treat patients with pancreatitis and its complications. This article addresses and summarizes pancreatic fluid collections and their management, with an emphasis on endoscopic drainage.     

Cellular thiols as a determinant of responsiveness to menadione in cardiomyocytes

The role of intracellular thiols in menadione-mediated toxicity was studied in neonatal rat cardiomyocytes. The sensitivity of cardiomyocytes to menadione was greater than that of skeletal muscle cells and 3T3 fibroblasts. Before cell degeneration, menadione induced marked depletion of intracellular thiols and an increase of oxidized glutathione. The sensitivity of these cells to menadione correlated with the level of depletion of intracellular thiols. After incubation of cardiomyocytes with menadione, glutathione reductase activity was inhibited and lipid peroxidation was increased. Both dicumarol (an inhibitor of DT-diaphorase) and diethyldithiocarbamate (an inhibitor of superoxide dismutase) enhanced the capacity of menadione to induce cellular damage and to cause depletion of intracellular glutathione. Decreasing intracellular glutathione by pretreatment of cells with N-ethylmaleimide or buthionine sulphoximine also increased menadione-induced cell degeneration. Preincubation with cysteine or dithiothreitol suppressed the capacity of menadione to damage the cells. Menadione-induced lipid peroxidation was also suppressed by the same treatment. These results show that the oxidative stress induced by menadione in cardiomyocytes results in the depletion of glutathione and protein thiols. Both DT-diaphorase and superoxide dismutase can protect cells from the toxicity of menadione. Cellular thiols are determinants of the responsiveness to menadione.     

What do they say about “Friends”? A cross-cultural study on Internet discussion forum

This exploratory study is to analyze the communication differences among viewers of US TV program Friends on Internet discussion forum in the US, Japan, and Taiwan. It intends to establish whether exposure to foreign TV could lead to similar communication content in the context of the virtual community between exporting and importing societies. Content analysis was used in this cross-cultural study, with the aim of understanding the ways in which dialogues posted on various discussion forums differed among the United States, Japan, and Taiwan. The results of this exploratory study support the notion that the process of cultural value influence is more complex than cultural imperialism advocates propose. Audiences respond actively rather than passively to foreign TV programs. Prior information structure of the audience is affecting the interpretation of subsequent information.