Tribological Characteristics of Smart Materials (Magneto-Rheological Fluids and Elastomers) and Their Applications

Magneto-rheological fluids (MRFs) and magneto-rheological elastomers (MREs), as smart materials, have been widely studied in various engineering fields to address vibration issues because the mechanical properties are controllable under the strength of a magnetic field. Their tribological characteristics are also important to be evaluated, as applications using MRFs and MREs contain various contact interfaces under reciprocating and rotating working conditions. The performance and durability of these materials are related to their tribological characteristics. Therefore, various working conditions and environmental conditions are taken into consideration, and their tribological characteristics are experimentally examined. In addition, applications using MRFs and MREs are introduced, and the tribological performances of these materials are evaluated

Putative cell adhesion membrane protein Vstm5 regulates neuronal morphology and migration in the central nervous system

During brain development, dynamic changes in neuronal membranes perform critical roles in neuronal morphogenesis and migration to create functional neural circuits. Among the proteins that induce membrane dynamics, cell adhesion molecules are important in neuronal membrane plasticity. Here, we report that V-set and transmembrane domain-containing protein 5 (Vstm5), a cell-adhesion-like molecule belonging to the Ig superfamily, was found in mouse brain. Knock-down of Vstm5 in cultured hippocampal neurons markedly reduced the complexity of dendritic structures, as well as the number of dendritic filopodia. Vstm5 also regulates neuronal morphology by promoting dendritic protrusions that later develop into dendritic spines. Using electroporationin utero, we found that Vstm5 overexpression delayed neuronal migration and induced multiple branches in leading processes during corticogenesis. These results indicate that Vstm5 is a new cell-adhesion-like molecule and is critically involved in synaptogenesis and corticogenesis by promoting neuronal membrane dynamics.SIGNIFICANCE STATEMENTNeuronal migration and morphogenesis play critical roles in brain development and function. In this study, we demonstrate for the first time that V-set and transmembrane domain-containing protein 5 (Vstm5), a putative cell adhesion membrane protein, modulates both the position and complexity of central neurons by altering their membrane morphology and dynamics. Vstm5 is also one of the target genes responsible for variations in patient responses to treatments for major depressive disorder. Our results provide the first evidence that Vstm5 is a novel factor involved in the modulation of the neuronal membrane and a critical element in normal neural circuit formation during mammalian brain development.</jats:p

Functional modulation of AMP-activated protein kinase by cereblon

AbstractMutations in cereblon (CRBN), a substrate binding component of the E3 ubiquitin ligase complex, cause a form of mental retardation in humans. However, the cellular proteins that interact with CRBN remain largely unknown. Here, we report that CRBN directly interacts with the α1 subunit of AMP-activated protein kinase (AMPK α1) and inhibits the activation of AMPK activation. The ectopic expression of CRBN reduces phosphorylation of AMPK α1 and, thus, inhibits the enzyme in a nutrient-independent manner. Moreover, AMPK α1 can be potently activated by suppressing endogenous CRBN using CRBN-specific small hairpin RNAs. Thus, CRBN may act as a negative modulator of the AMPK signaling pathway in vivo

Effect of Apneic Oxygenation via Nasal Prong on Gas Exchange and Vital Signs during Fiberoptic Intubation under General Anesthesia

A clinical study for the evaluation of the effect of apneic oxygenation by nasal prong during fiberoptic orotracheal intubation on gas exchange and vital signs has been done on the patients who received tympanomastoidectomy (ASA c1assfication 1 and 2, aged from 20 to 40). Among them, 22 patients were selected whose fiberoptic intubation lasted more than 3 but less than 4 minutes, to observe the changes of Pa02, PaC02, HR, and MAP. 11 patients who underwent fiberoptic orotracheal intubation in apneic state without oxygen administration (Group I) showed similar increases in vital signs to the other 11 patients who received apneic oxygenation (Group II). PaC02 increased more in Group I than in Group II, which was not statistically significant. The differences of Pa02 at 1 and 2 minutes between two groups after removal of oxygen mask and beginning of fiberoptic intubation, were not statistically significant but Group II showed a significantly lesser degree of decrease in Pa02 at 3 minutes. We might say that apneic oxygenation during fiberoptic intubation under general anesthesia is useful because it could delay the onset of hypoxia, thereby provide extra time for intubation. Therefore we could attempt intubation up to 3 minutes on the fully relaxed patient, if we give oxygen via nasal prong

Joint Transmit and Receive Filters Design for Multiple-Input Multiple-Output (MIMO) Systems

Manuscript received April 18, 2003; revised January 19, 2004; accepted April 8, 2004. The editor coordinating the review of this paper and approving it for publication is R. Murch.Multiple transmit (Tx) and multiple receive (Rx) antennas systems, referred to as multiple-input multiple-output (MIMO) systems, have been proposed to achieve higher data rates in wireless communication systems. In this paper, we investigate joint design of transmitter and receiver for the MIMO system when the channel information is available at both transmitter and receiver. We discuss the problem concerning the design of Tx and Rx filters with the aim of minimizing the bit-error probability (BEP).We derive the optimum Tx and Rx filters when the number of data symbols is two. For a general number of data symbols, we derive a Tx and Rx filters design criterion referred to as equal signal-to-noise plus interference ratio (SNIR) criterion, and propose Tx and Rx filters based on this equal SNIR criterion. The performance of the proposed filter is compared with that of the conventional minimum mean-squared error (MMSE) filter. Performance analysis shows that the proposed filter provides a significant improvement over the MMSE filter in BEP and spectral efficiency