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Bestrophin-1 (Best1) is a calcium (Ca

The elevated temperature strength of multicomponent Al-Si alloys is greatly affected by the volume fraction and the interconnectivity of hard phases formed upon solidification. In the present investigation, such influences were examined for two Al-Si-Cu-Ni alloys with different total volume fractions of hard phases. To control the microstructural features related to the size of the phase, the specimens were prepared with and without ultrasonic melt treatment (UST) at different cooling rates. The microstructures of the alloys were composed of primary Si, eutectic Si, (Al,Si)3(Zr,Ni,Fe), Al9FeNi and Al3(Cu,Ni)2 phases. The microstructural features, such as the size and aspect ratio of each phase, changed with UST and cooling rate, and accordingly, the elevated temperature strength at 350 oC was changed. The alloy with a high volume fraction of about 30 vol.% exhibited increased elevated temperature strength at 350 oC when ultrasonic melt treated, and the alloy having a volume fraction as low as about 18 vol.% exhibited the opposite results. Considering the microstructural features of the multi-component Al-Si alloy, a hexagonal shear-lag model was suggested, based on the well-known shearlag model proposed by Nardone and Prewo (Scr. Metall. 20;1986:43-48). Using the 2-D microstructural factors such as the size, aspect ratio of the phase and secondary dendrite arm spacing, the elevated temperature strength was calculated and compared with the measured value. Based on the hexagonal shear-lag model, the influence of microstructural factors on the elevated temperature strength was discussed for multi-component Al-Si-Cu-Ni alloys.

20 μM TFP-treated group. The cell were recorded in 2 h after seeding on 6-well plate equipped with x10 objective lens. The video were recorded by Cell Observer (Carl Zeiss, Germany).

Supplementary Figure S1. TFP induces morphological change of U87MG cells, and cell death; Supplementary Figure S2. Body weight is not changed during TFP injection in in vivo glioblastoma skin xenograft model; Supplementary Figure S3. IP3R1, 2 and 3 shRNA knockdown test by western blot and functional knockdown test using GBL 28 primary glioblastoma cells; Supplementary Figure S4. TFP reduces cell viability of several GBL cells;Supplementary Table S1. IP3R 1, 2, 3 and CaM shRNA sequences

0.9% saline-treated control group. The cell were recorded in 2 h after seeding on 6-well plate equipped with x10 objective lens.

Monoamine oxidase B (MAOB) is a key enzyme for GABA production in astrocytes in several brain regions. To date, the role of astrocytic MAOB has been studied in MAOB null knockout (KO) mice, although MAOB is expressed throughout the body. Therefore, there has been a need for genetically engineered mice in which only astrocytic MAOB is targeted. Here, we generated an astrocyte-specific MAOB conditional KO (cKO) mouse line and characterized it in the cerebellar and striatal regions of the brain. Using the CRISPR-Cas9 gene-editing technique, we generated

The Golgi apparatus is a critical intracellular organelle that is responsible for modifying, packaging, and transporting proteins to their destinations. Golgi homeostasis involving the acidic pH, ion concentration, and membrane potential, is critical for proper functions and morphology of the Golgi. Although transporters and anion channels that contribute to Golgi homeostasis have been identified, the molecular identity of cation channels remains unknown. Here we identify TMEM87A as a novel Golgi-resident cation channel that contributes to pH homeostasis and rename it as GolpHCat (GolgipH-sensitiveCation channel). The genetic ablation of GolpHCat exhibits an impaired resting pH in the Golgi. Heterologously expressed GolpHCat displays voltage- and pH-dependent, non-selective cationic, and inwardly rectifying currents, with potent inhibition by gluconate. Furthermore, reconstitution of purified GolpHCat in liposomes generates functional channel activities with unique voltage-dependent gating and ion permeation. GolpHCat is expressed in various cell types such as neurons and astrocytes in the brain. In the hippocampus, GolpHCat-knockout mice show dilated Golgi morphology and altered glycosylation and protein trafficking, leading to impaired spatial memory with significantly reduced long-term potentiation. We elucidate that GolpHCat, by maintaining Golgi membrane potential, regulates ionic and osmotic homeostasis, protein glycosylation/trafficking, and brain functions. Our results propose a new molecular target for Golgi-related diseases and cognitive impairment.

The effect of ultrasonic melt treatment (UST) on the solidification microstructure of an Al–5Ti–1B alloy containing high-volume fractions of Al3Ti and TiB2 particles is investigated for various UST times with different melt holding times. The as-cast Al–5Ti–1B alloy is composed of TiB2 and polygonal Al3Ti particles (present prior to UST), plate-like Al3Ti particles, and Al grains (formed during UST and/or solidification). The UST causes a size reduction and homogeneous distribution of the TiB2-agglomerated region containing many submicron-sized TiB2 particles pushed to the grain boundaries. The UST slightly decreases the size and improves the distribution of polygonal Al3Ti particles enriched in the TiB2-agglomerated region. Unlike the TiB2 and polygonal Al3Ti particles, which exhibit a minor refining effect, the plate-like Al3Ti particles show a significant refinement with UST application. The UST has a significant effect on the size distribution of Al grains by inducing the formation of medium-sized grains at the expense of small and large grains; however, it only has a slight effect on grain refinement. The degree of microstructure modification increases with increasing UST time but decreases with melt holding time after UST. The mechanisms for the refinement and dispersion of the TiB2 and Al3Ti particles and Al grains are discussed considering fragmentation, nucleation, and growth behaviors induced by the UST and subsequent solidification.

The principal inhibitory transmitter, γ-aminobutyric acid (GABA), is critical for maintaining hypothalamic homeostasis and released from neurons phasically, as well as from astrocytes tonically. Although astrocytes in the arcuate nucleus (ARC) of the hypothalamus are shown to transform into reactive astrocytes, the tonic inhibition by astrocytic GABA has not been adequately investigated in diet-induced obesity (DIO). Here, we investigated the expression of monoamine oxidase-B (MAOB), a GABA-synthesizing enzyme, in reactive astrocytes in obese mice. We observed that a chronic high-fat diet (HFD) significantly increased astrocytic MAOB and cellular GABA content, along with enhanced hypertrophy of astrocytes in the ARC. Unexpectedly, we found that the level of tonic GABA was unaltered in chronic HFD mice using whole-cell patch-clamp recordings in the ARC. Furthermore, the GABA-induced current was increased with elevated GABA

This work probes the effect of ultrasonic melt treatment (UST) on primary intermetallic particles and α-Al using pure Al and Al–Zr alloys (Al–0.3Zr–0.1Ti, Al–0.5Zr, Al–0.5Zr–0.5Mg–0.9Si) solidified at various cooling rates of 0.2–70 K s−1. The application of UST is shown to decrease the size and increase the number density and volume fraction of D023-structured primary Al3Zr and Al3(Zr,Ti) particles with a high nucleation potency for α-Al formation. High-resolution transmission electron microscopy analysis reveals that the cavitation-induced wetting and dispersion of γ-Al2O3 inoculant particles contribute to the refinement of primary intermetallic particles. The grain size of Al–Zr alloys increases with increasing cooling rate because of the concomitantly reduced formation of primary intermetallic inoculant particles. The UST-induced refinement of primary Al3Zr particles and the increased number density lead to grain refinement in Ti-free Al–Zr alloys. For the Ti-containing Al–Zr alloy, UST-induced grain refinement is achieved only at a very low cooling rate of 0.2 K s−1, possibly because of the side effects of UST on the growth-restricting influence of Ti. The fast cooling–induced solidification enables significant age-hardening by L12-Al3Zr nanoprecipitation (~5 nm) and is not affected by UST. Thus, this study shows that UST can be used to reduce the degree of grain coarsening of age-hardenable Al–Zr alloys at high cooling rates.

Ultrasonic melt treatment (UST) is known for refining microstructures including intermetallic compound (IMC)s, and it is expected that the microstructural benefits induced by UST may reduce the tim...

Nociceptors are known to directly recognize bacterial cell wall components or secreted toxins, thereby leading to pain induced by bacterial infection. However, direct activation of nociceptors by bacterial metabolites remains unclear even though bacteria produce numerous metabolites related to health and disease. In the current study, we investigated whether and how a common bacterial metabolite, indole, which is produced by normal microflora of the gastrointestinal (GI) tract and oral cavity, can directly activate nociceptive sensory neurons. We found that indole elicits calcium response and evokes inward currents in subsets of dorsal root ganglia (DRG) neurons. Intraplantar (i.pl.) injection of indole produced nocifensive behaviors in adult mice, which were enhanced in complete Freund's adjuvant (CFA)-induced chronic inflammatory condition. Indole increased calcitonin gene-related peptide (CGRP) release in DRG neurons, and i.pl. injection of indole increased hind paw thickness, suggesting its role in generation of neurogenic inflammation. These in vitro and in vivo indole-induced responses were pharmacologically blocked by transient receptor potential ankyrin 1 (TRPA1) antagonist, HC-030031, and significantly abolished in TRPA1 knockout (KO) mice, indicating that indole targets TRPA1 for its action in DRG neurons. Nocifensive licking behavior induced by the injection of live Escherichia coli was significantly decreased in tryptophanase mutant (TnaA KO) E. coli-injected mice that lack indole production, further supporting the idea that bacteria-derived indole can induce pain during infection. Identifying the mechanism of action of indole through TRPA1 provides insights into bacteria-neuron interactions and the role of bacterial metabolites in pain signaling, especially in inflammation-accompanied bacterial infection.

Ultrasonic melt treatment (UST) was applied to Al-7Si-2Cu-1Mg melt at various temperatures of 620, 650, 700 and 785 °C. MgAl2O4 particles which were often found to be densely populated along oxide films, became effectively dispersed and well-wetted by UST. Transmission electron microscopy work combined with crystallography analysis clearly indicates that MgAl2O4 particles can act as α-Al nucleation site with the aid of UST. However, with UST, grain refinement occurred only at temperature of 620 °C and the grain size increased from 97 to 351 μm with increase of melt temperature to 785 °C for UST. In quantitative analysis of grain size and MgAl2O4 particle diameter, it was found that ultrasonic de-agglomeration decreased mean particle size of the MgAl2O4 particles, significantly reducing size from 1.2 to 0.4 μm when temperature increased from 620 to 785 °C. Such a size reduction with increased number of MgAl2O4 particles does not always guarantee grain refinement. Thus, in this work, detailed condition for achieving grain refinement by UST is discussed based on quantitative measurement. Furthermore, we tried to suggest the most valid grain refinement mechanism among the known mechanisms by investigation of the relationship between grain size and particle size with variation of melt temperature.

The correlation between primary Si and silicide refinement induced by ultrasonic treatment (UST) of multicomponent Al–Si alloy containing Ti, Zr, V, and P was investigated. UST significantly refined the primary Si phase owing to cavitation-induced wetting and deagglomeration of MgAl2O4 particles. Lowering the UST finish temperature caused deterioration of the degree of primary Si refinement, instead leading to silicide refinement. Cavitation-induced silicide nucleation on wetted MgAl2O4 consumed the MgAl2O4 particles, particularly in the case of primary Si nucleation. Similarly, the formation of an AlP phase on the silicide phase reduced the nucleation efficiency of the AlP phase. Poisoning of the MgAl2O4 and AlP phases by the silicide phase was responsible for the deterioration in primary Si refinement. Room-temperature tensile strength and high-temperature elongation were increased by UST and were dependent on the size of primary Si.

Aluminum alloys have been widely used in various industries, and continuous improvement in the properties of these alloys is required to meet consumer demand for high-performance devices. This review introduces five recent case studies where the CALPHAD method was applied in the development of high-performance Al alloys. CALPHAD calculations can reasonably predict the solidification microstructure of the Al-7Si-2Cu-1Mg alloy and 4343/3527/4343 brazing sheets, although, some deviations are caused by solid-state diffusion occurring during the actual solidification process. CALPHAD is useful for predicting the complex solidification behavior of Al-(12-18)Si piston alloys and Al-6Mg-9Si-10Cu-10Zn-3Ni natural composites, and the precipitation behavior of the Al matrix. The application of CALPHAD can also provide valuable information on the properties of Al alloys, such as that on the erosion of brazing sheets, fluidity of alloy melts, and refinement of secondary phases by melt treatment.

We present the world-first demonstration of 28-nm embedded MRAM (eMRAM) for frame buffer memory, highlighting the smallest macro size (0.08 mm2/Mb) reported to date. Compared to SRAM that is commonly used for frame buffer memory, eMRAM provides 47% area saving. For frame buffer applications, read disturbance and endurance are the most critical reliability considerations. With magnetic tunnel junction process improvements, we have verified sufficient read disturbance margins and met the endurance requirement (> 1E10 cycles) which corresponds to 10-year continuous usage. Compared to flash-type eMRAM, we have achieved 40% switching current reduction with < 50ns read/write speed.

In this study, microstructural evolution during solidification of a hypereutectic Al&ndash, Mn&ndash, Fe&ndash, Si alloy was investigated using semi-quantitative two-/three-dimensional phase-field modeling. The formation of facetted Al6Mn precipitates and the temperature evolution during solidification were simulated and experimentally validated. The temperature evolution obtained from the phase-field simulation, which was balanced between extracted heat and latent heat release, was compared to the thermal profile of the specimen measured during casting to validate the semi-quantitative phase-field simulation. The casting microstructure, grain morphology, and solute distribution of the specimen were analyzed using electron backscatter diffraction and energy-dispersive spectroscopy and compared with the simulated microstructure. The simulation results identified the different Fe to Mn ratios in Al6(Mnx,Fe1&minus, x) precipitates that formed during different solidification stages and were confirmed by energy-dispersive spectroscopy. The precipitates formed in the late solidification stage were more enriched with Fe than the primary precipitate due to solute segregation in the interdendritic channel. The semi-quantitative model facilitated a direct comparison between the simulation and experimental observations.

The effect of Cu/Mg solute combined with ultrasonic melt treatment (UST) on the microstructure and mechanical properties of a hypoeutectic Al-7Si alloy was investigated. Cu up to 4 wt pct and Mg to 1 wt pct were added to the alloy and UST was performed at about 100 °C above the liquidus temperature. UST at such a high temperature was ineffective in refining grain sizes but enhanced the microstructural homogeneity of the alloys with the refinement of α-Al secondary dendrite arm spacing (SDAS). It was found that both the grain size and the SDAS were solute sensitive: In the Al-7Si alloy with UST they insignificantly changed with Cu but decreased with an increase in Mg content. Along with the structural refinement, UST was likely to affect the solute redistribution and the subsequent formation of secondary phases (e.g., eutectic Si and Cu/Mg-rich intermetallic compounds (IMCs)). Quantitative analysis indicated that UST had significantly minimized microsegregation of Cu and Mg solutes, decreasing the amount of the IMCs finely and uniformly distributed. The underlying reason was attributed to the reduction in the size of the SDAS, which enabled the solid-state diffusion to occur more efficiently upon solidification. The most significant increase in the tensile properties was achieved for the Al-7Si-2Cu-1Mg alloy with UST where the SDAS was well refined and the grain size was the smallest among the alloys investigated. The important role of UST on the casting structure refinement and the solute distribution is discussed and the resulting mechanical properties are further explored.

Candida albicans is a yeast pathogen known for its virulence and high morbidity rate, and it easily colonizes host tissues and implant devices and forms mature biofilms, which play an important role in pathogenesis and drug resistance. In this study, we investigated the abilities of thermoresponsive oligomers of N-vinylcaprolactam (OVCLs) to inhibit biofilm formation by C. albicans. One synthetic and four commercial OVCLs (≤MW 240 000) at a concentration of 5 μg ml-1 were found to decrease C. albicans biofilm formation by more than 90% at 37°C, but to be less effective at 25°C. Microscopic observations showed that OVCLs clearly inhibited hyphal formation and cell aggregation by C. albicans, and this appeared to be responsible for their antibiofilm effects. In addition, effective antibiofouling coatings of OVCL/poly(lactic-co-glycolic acid) polymer blends were prepared on glass surfaces. Significance and impact of the study The emergence of multidrug-resistant Candida strains has prompted searches for new antifungals. The antibiofilm and antihyphae properties of OVCLs and OVCL coating against a fluconazole-resistant Candida albicans strain are present in this study. These findings suggest that OVCL and OVCL-coated biomaterials are potentially useful for controlling fungal biofilm formation by and the virulence of antifungal-resistant C. albicans.

Ultrasonic melt treatment (UST) was applied to an A390 hypereutectic Al–Si alloy in a temperature range of 750–800 °C and its influence on the solidification structure and the consequent increase in strength was investigated. UST at such a high temperature, which is about 100 °C above the liquidus temperature, had little effect on the grain refinement but enhanced the homogeneity of the microstructure with the uniform distribution of constituent phases (e.g. primary Si, α-Al and intermetallics) significantly refined. With the microstructural homogeneity, quantitative analysis confirmed that UST was found to suppress the formation of Cu-bearing phases, i.e., Q-Al5Cu2Mg8Si6, Al2Cu phases that form in the final stage of solidification while notably increasing the average Cu contents in the matrix from 1.29 to 2.06 wt%. A tensile test exhibits an increase in the yield strength of the as-cast alloy from 185 to 208 MPa, which is mainly associated with the solute increment within the matrix. The important role of UST in the microstructure evolution during solidification is discussed and the mechanism covering the microstructure-strengthening interrelationship of the ultrasonically treated A390 alloy is proposed.

A mechanism describing the synergistic effect of ultrasonic melt treatment (UST) and subsequent fast cooling on the refinement of primary Si particles in a hypereutectic Al−Si alloy was investigated by examining inoculant particles via high-resolution transmission electron microscopy, serial sectioning, and melt filtration. The application of UST activated non-wetting MgAl2O4 particles with diameters of ∼0.5 μm to nucleate the primary Si phase. The cavitation-enhanced wetting of MgAl2O4 particles caused the formation of the AlP phase at the MgAl2O4 interface, further improving the nucleation potential. The cavitation-enhanced wetting and dispersion of inclusions (such as MgAl2O4) also resulted in the refinement and de-agglomeration of AlP particles. The UST-induced changes to the inoculant particles ultimately increased their number density, and the observed effects became more pronounced after increasing the degree of undercooling up to 20 K, leading to enhanced refinement of primary Si particles at higher cooling rates (up to 102 K s−1).

This paper shows that the addition of transition elements significantly influences the microstructure and tensile properties of Al–12Si alloy cast under ultrasonic melt treatment (UST). The alloys contained primary Si, eutectic Si and a variety of intermetallic compounds (IMCs); the addition of Mn and Ni changed the solidification sequence by forming primary α-Al15(Fe,Mn)4Si2 and e-Al3Ni prior to primary Si formation. The primary Si and primary IMCs competitively consumed the nucleation sites introduced by UST, thereby influencing their refining efficiencies; the efficiency of primary Si refinement by UST increased with increasing the fraction of primary Si formed prior to IMC formation, whereas it deteriorated with increasing primary IMC fraction. The refining efficiency of eutectic Si and eutectic IMCs was not affected by the type and fraction of the primary phase. Using a Ti sonotrode for UST caused Ti contamination, resulting in grain refinement by forming Ti(Al,Si)3 particles and increasing the amount of Ti solutes. Regardless of transition elements content, the application of UST improved the tensile strength at 25 °C and 350 °C. The refinement of IMCs caused by UST allowed the alloy to contain more IMCs without deterioration of room-temperature tensile strength. This enhanced the increment of high-temperature tensile strength by IMCs. Ductility of heavily alloyed systems was also improved by UST.

The effects of ultrasonic melt treatment (UST) and solution treatment on the microstructure and mechanical properties of a low-density multicomponent Al70Mg10Si10Cu5Zn5 alloy at room and elevated temperatures were investigated. The as-cast Al70Mg10Si10Cu5Zn5 alloy was composed of an fcc Al solid-solution, coarse secondary phases (5–30 μm), fine Cu-containing precipitates (

The effects of ultrasonic melt treatment (UST) on the microstructure and tensile properties of three multicomponent Al Si alloys with different Si contents (12, 15, and 18 wt%Si) and solution treatments were systematically investigated at room and elevated (350 °C) temperatures. The microstructures of these alloys consisted of primary Si, eutectic Si, Mg2Si, and various types of aluminides, but the average size and area fraction of the primary Si increased with Si content. The application of UST caused a transformation from dendritic to equiaxed cells and a reduction in grain size, with a significant reduction in the size of all secondary phases (i.e., Si, Mg2Si and aluminides). Both the strength and ductility at room and elevated temperatures were greatly improved by UST, mainly due to microstructure refinement. Improvements in the high-temperature tensile strength as a result of UST increased with increasing Si contents, due to the enhanced refinement of primary Si by UST with increasing Si contents. The spherodization of rigid phases induced by solution treatment can improve the strength and ductility at room temperature, but can also cause a loss of strength at elevated temperatures due to the relaxation of the interconnected network structure of rigid phases caused by their spherodization.

Calcium (Ca2+) signaling is an important signaling process, implicated in cancer cell proliferation and motility of the deadly glioblastomas that aggressively invade neighboring brain tissue. We have previously demonstrated that caffeine blocks glioblastoma invasion and extends survival by inhibiting Ca2+ release channel inositol 1,4,5-trisphosphate receptor (IP3R) subtype 3. Trifluoperazine (TFP) is an FDA-approved antipsychotic drug for schizophrenia. Interestingly, TFP has been recently reported to show a strong anticancer effect on lung cancer, hepatocellular carcinoma, and T-cell lymphoma. However, the possible anticancer effect of TFP on glioblastoma has not been tested. Here, we report that TFP potently suppresses proliferation, motility, and invasion of glioblastoma cells in vitro, and tumor growth in in vivo xenograft mouse model. Unlike caffeine, TFP triggers massive and irreversible release of Ca2+ from intracellular stores by IP3R subtype 1 and 2 by directly interacting at the TFP-binding site of a Ca2+-binding protein, calmodulin subtype 2 (CaM2). TFP binding to CaM2 causes a dissociation of CaM2 from IP3R and subsequent opening of IP3R. Compared with the control neural stem cells, various glioblastoma cell lines showed enhanced expression of CaM2 and thus enhanced sensitivity to TFP. On the basis of these findings, we propose TFP as a potential therapeutic drug for glioblastoma by aberrantly and irreversibly increasing Ca2+ in glioblastoma cells. Mol Cancer Ther; 16(1); 217–27. ©2016 AACR.

The combined effects of ultrasonic melt treatment (UST) with the cooling rate on the microstructural evolution in a multicomponent Al-14Si-CuNiMg casting alloy was investigated. UST was applied to a melt at 800°C, followed by casting into a steel step mold at cooling rates in the range of 4-32 K/s. UST in the fully liquid state significantly reduced the sizes of the primary phases (the phases formed before Al) crystallized in the initial stage of solidification, and the structural refinement by UST became more pronounced for a faster cooling. With trace additions of Ti, V and Zr, the primary phase is most likely (Al,Si)3(Zr,Ni,Fe), and primary Si and then Al3Ni are sequentially formed upon solidification. AlP particles, well-known nucleants for primary Si, were also found to exist inside the (Al,Si)3(Zr,Ni,Fe) and Al3Ni which exhibited a very low lattice misfit with AlP (~0.7 and 4.7%, respectively). This importantly suggests that AlP can nucleate all the primary phases while it has the highest efficiency of structural refinement by UST for (Al,Si)3(Zr,Ni,Fe) phase that first nucleated in the molten metal. The nucleation of the primary phases was quantified using an analytical model based on exponential statistics. The hierarchical refinement operated by UST is further discussed.

The effects of ultrasonic melt treatment (UST) on the microstructure and mechanical properties of Al-12.2Si-3.3Cu-2.4Ni-0.8Mg-0.1Fe (wt%) piston alloy were systematically investigated. Rigid colonies consisting of primary Si, eutectic Si, Mg 2 Si and various aluminides (e-Al 3 Ni, δ-Al 3 CuNi, π-Al 8 FeMg 3 Si 6 , γ-Al 7 Cu 4 Ni, Q-Al 5 Cu 2 Mg 8 Si 6 and θ-Al 2 Cu) were observed in the as-cast alloys. The sizes of the secondary phases, eutectic cell and grain were significantly decreased by UST because of the enhanced nucleation of each phase under ultrasonic irradiation. The yield strength, tensile strength and elongation at 25 °C were significantly improved by UST mainly because of the refinement of the microstructures. Both tensile strength and elongation at 350 °C were also improved by UST despite the unchanged yield strength.

Aluminum matrix composites with a high volume fraction of B4C and TiB2 were fabricated by a novel processing technique - a quick spontaneous infiltration process. The process combines a pressureless infiltration with the combustion reaction of Al-Ti-B4C-CuO in molten aluminum. The process is realized in a simple and economical way in which the whole process is performed in air in a few minutes. To verify the rapidity of the process, the infiltration kinetics was calculated based on the Washburn equation in which melt flows into a porous skeleton. However, there was a noticeable deviation from the calculated results with the experimental results. Considering the cross-sections of the samples at different processing times, a new infiltration model (two step infiltration) consisting of macro-infiltration and micro-infiltration is suggested. The calculated kinetics results in light of the proposed model agree well with the experimental results.

A trace addition of Zr to a multicomponent Al-14Si-3Cu-4.5Ni casting alloy has often been found to form a coarse plate-like Zr-rich intermetallic compound with a size of a few tens of μm at the beginning of solidification. Evaluation of the phase composition has confirmed that the Zr-rich intermetallic phase consists of multicomponent constituent elements, mainly Al, Si, Ni and Fe, and is present in a form of (Al,Si)3(Zr,Ni,Fe). The existence of such a complex (Al,Si)3(Zr,Ni,Fe) phase has not yet been predicted by phase equilibria calculation of the multicomponent Al-14Si-CuNiMg systems. In this paper, transmission electron microscopy studies combined with electron backscattered diffraction pattern analysis reveals the crystallography information of the (Al,Si)3(Zr,Ni,Fe) phase for the first time and identifies it as a modified Al3Zr-D023 crystal (tetragonal, I4/mmm(139)) with slightly changed lattice parameters of a = b = 3.275 A and c = 15.475 A. The primary (Al,Si)3(Zr,Ni,Fe) phase is found to nucleate directly onto AlP particles. The mechanical properties of the Zr-rich intermetallics were also investigated using nanoindentation at both room and elevated temperatures and were compared to those of the Si phase.

Al–xMg–10Si–10Cu–10Zn (in wt%) alloy is fabricated with a high volume fraction of coarse multi-phase particles in the aluminum matrix. Permanent mold casting is carried out with a selective ultrasonic melt-treatment for 60 s at 1000 K. A step mold is used to achieve three different cooling rates. Blocky primary Mg2Si particles are homogeneously distributed through the Al matrix and eutectic phases such as Si, Q–Al5Cu2Mg8Si6, and θ-Al2Cu are found in the dendritic boundaries. Ultrasonication significantly decreases the porosity and the size of microstructural constituents such as primary Mg2Si phases. Refinement of primary Mg2Si by ultrasonication is more effective in the specimens with higher cooling rates. The compressive properties at room temperature and 623 K are enhanced in the ultrasonicated alloys. By heat treatment at 713 K, very fine θ′ precipitates with size less than 10 nm are formed through the Al matrix and blocky Mg2Si and Q phases were spheroidized.

A fully integrated 3–5 GHz CMOS IR-UWB RFIC for location based system is implemented on 0.18 μm CMOS technology. The receiver architecture adopts the energy detection method and OOK modulated signal is used. For high speed sampling, the equivalent time sampling technique is used and 4 bit ADC is also integrated. The digitally synthesized impulse transmitter is employed. The receiver's sensitivity is −85.7 dBm and consumes 32 mA at 1.8 V supply.

In this study we describe measures taken in our laboratory to improve the long-term precision of nitrate and ammonia analysis in seawater using a microflow segmented-flow analyzer. To improve the nitrate reduction efficiency using a flow-through open tube cadmium reactor (OTCR), we compared alternative buffer formulations and regeneration procedures for an OTCR. We improved long-term stability for nitrate with a modified flow scheme and color reagent formulation and for ammonia by isolating samples from the ambient air and purifying the air used for bubble segmentation. We demonstrate the importance of taking into consideration the residual nutrient content of the artificial seawater used for the preparation of calibration standards. We describe how an operating procedure to eliminate errors from that source as well as from the refractive index of the matrix itself can be modified to include the minimization of dynamic refractive index effects resulting from differences between the matrix of the samples, the calibrants, and the wash solution. We compare the data for long-term measurements of certified reference material under two different conditions, using ultrapure water (UPW) and artificial seawater (ASW) for the sampler wash.

A feasible approach to fabricate an Al alloy composite reinforced with TiC and Al 2 O 3 (hereinafter, (TiC + Al 2 O 3 )/Al alloy composite) based on in-situ processing at low temperatures was proposed. With appropriate amounts of excess Al added to the (4Al + 3TiO 2 + 3C) powder system, the spontaneous combustion reactions for forming TiC and Al 2 O 3 were promoted, whereas a small amount of CuO added to the reagent powders caused triggering of the combustion reaction at lower temperatures (860 °C), which was thereafter self-maintaining. The TiC and Al 2 O 3 particles thus formed could be dispersed uniformly in the Al matrix and contributed to a considerable increase in the strength and stiffness of the resultant composite material, demonstrating the feasibility of the proposed technique for producing metal matrix composites for load-bearing applications. In this study, we report the method used to fabricate the (TiC + Al 2 O 3 )/Al alloy composite at low temperatures, its synthesis, and the resultant properties.

The effect of Ni on the thermal conductivity and fluidity of a low Si-added Al–Si casting alloy was investigated. The room temperature thermal conductivity of an Al–2 wt%Si alloy instantly dropped when adding 0.5 wt%Ni, whereas further additions of Ni up to 3 wt% had little influence on the thermal conductivity, which was in the range of 180–185 W/mK. The thermal conductivity was also estimated for the alloys cast at various cooling rates by measuring the electrical conductivity using the Wiedemann–Franz law and increased nearly linearly with an increase in the cooling rates. At such a low level of 2 wt%Si, the castability of the Al–Si alloys, which was evaluated by a fluidity spiral test, was enhanced by the Ni additions, exhibiting the maximum fluidity length at 0.5 wt%Ni.

Astrocytes and neurons are inseparable partners in the brain. Neurotransmitters released from neurons activate corresponding G protein-coupled receptors (GPCR) expressed in astrocytes, resulting in release of gliotransmitters such as glutamate, D-serine, and ATP. These gliotransmitters in turn influence neuronal excitability and synaptic activities. Among these gliotransmitters, ATP regulates the level of network excitability and is critically involved in sleep homeostasis and astrocytic Ca(2+) oscillations. ATP is known to be released from astrocytes by Ca(2+)-dependent manner. However, the precise source of Ca(2+), whether it is Ca(2+) entry from outside of cell or from the intracellular store, is still not clear yet. Here, we performed sniffer patch to detect ATP release from astrocyte by using various stimulation. We found that ATP was not released from astrocyte when Ca(2+) was released from intracellular stores by activation of Gαq-coupled GPCR including PAR1, P2YR, and B2R. More importantly, mechanical stimulation (MS)-induced ATP release from astrocyte was eliminated when external Ca(2+) was omitted. Our results suggest that Ca(2+) entry, but not release from intracellular Ca(2+) store, is critical for MS-induced ATP release from astrocyte.

Controlling the processing parameters is important to minimize such undesirable microstructural features in Al/TiC composites as unreacted C, incomplete reaction products of Al3Ti and TiC aggregates, which originate from the pellet microstructure upon the combustion reaction of an Al-Ti-C-CuO pellet in an Al melt. In particular, the mean particle size of elemental powders is a key factor linked to the formation of TiC aggregates, which is significantly suppressed with smaller initial particles of Ti and C by mixing them homogenously by ball milling. Al-Cu-Mg alloys reinforced with up to 12 vol pct TiC are fabricated by the developed process, followed by extrusion. The composites after heat treatment exhibit high elastic modulus and an ultimate tensile strength of 93 GPa and 461 MPa, respectively, with a low coefficient of thermal expansion of 17.11 ppm/K.