Localized Dielectric Loss Heating in Dielectrophoresis Devices

Temperature increases during dielectrophoresis (DEP) can affect the response of biological entities, and ignoring the effect can result in misleading analysis. The heating mechanism of a DEP device is typically considered to be the result of Joule heating and is overlooked without an appropriate analysis. Our experiment and analysis indicate that the heating mechanism is due to the dielectric loss (Debye relaxation). A temperature increase between interdigitated electrodes (IDEs) has been measured with an integrated micro temperature sensor between IDEs to be as high as 70 °C at 1.5 MHz with a 30 Vpp applied voltage to our ultra-low thermal mass DEP device. Analytical and numerical analysis of the power dissipation due to the dielectric loss are in good agreement with the experiment data

A Patterned Single Layer Graphene Resistance Temperature Sensor

Micro-fabricated single-layer graphenes (SLGs) on a silicon dioxide (SiO2)/Si substrate, a silicon nitride (SiN) membrane, and a suspended architecture are presented for their use as temperature sensors. These graphene temperature sensors act as resistance temperature detectors, showing a quadratic dependence of resistance on the temperature in a range between 283 K and 303 K. The observed resistance change of the graphene temperature sensors are explained by the temperature dependent electron mobility relationship (~T−4) and electron-phonon scattering. By analyzing the transient response of the SLG temperature sensors on different substrates, it is found that the graphene sensor on the SiN membrane shows the highest sensitivity due to low thermal mass, while the sensor on SiO2/Si reveals the lowest one. Also, the graphene on the SiN membrane reveals not only the fastest response, but also better mechanical stability compared to the suspended graphene sensor. Therefore, the presented results show that the temperature sensors based on SLG with an extremely low thermal mass can be used in various applications requiring high sensitivity and fast operation

High-resolution analysis of condition-specific regulatory modules in Saccharomyces cerevisiae

A novel approach for identifying condition-specific regulatory modules in yeast reveals functionally distinct coregulated submodules

Elevated cellular cholesterol in Familial Alzheimer’s presenilin 1 mutation is associated with lipid raft localization of β-amyloid precursor protein

Familial Alzheimer’s disease (FAD)-associated presenilin 1 (PS1) serves as a catalytic subunit of γ-secretase complex, which mediates the proteolytic liberation of β-amyloid (Aβ) from β-amyloid precursor protein (APP). In addition to its proteolytic role, PS1 is involved in non-proteolytic functions such as protein trafficking and ion channel regulation. Furthermore, postmortem AD brains as well as AD patients showed dysregulation of cholesterol metabolism. Since cholesterol has been implicated in regulating Aβ production, we investigated whether the FAD PS1-associated cholesterol elevation could influence APP processing. We found that in CHO cells stably expressing FAD-associated PS1 ΔE9, total cholesterol levels are elevated compared to cells expressing wild-type PS1. We also found that localization of APP in cholesterol-enriched lipid rafts is substantially increased in the mutant cells. Reducing the cholesterol levels by either methyl-β-cyclodextrin or an inhibitor of CYP51, an enzyme mediating the elevated cholesterol in PS1 ΔE9-expressing cells, significantly reduced lipid raft-associated APP. In contrast, exogenous cholesterol increased lipid raft-associated APP. These data suggest that in the FAD PS1 ΔE9 cells, the elevated cellular cholesterol level contributes to the altered APP processing by increasing APP localized in lipid rafts

Functional Characterization of Siberian Wild Rye Grass \u3cem\u3eEsHSP 16.9\u3c/em\u3e Gene Conferring Diverse Stress Tolerance in Prokaryotic Cells

Siberian wild rye (Elymus sibiricus L.) is a perennial, caespitose, and self-pollinating grass indigenous to Northern Asia and also is widely distributed from Northern Europe to Japan. The plant shows strong environmental adaptability with tolerance to drought and cold; thus, it is often used as forage resources (Yan et al., 2007). Environmental stresses caused by global warming are acknowledged to be as a serious issue in agriculture due to reductions of crop productivity (Ahuja et al., 2010). Genetic natural breeding of Siberian wild rye would potentially increase the productivity of forage crops; however, genetic studies on this grass have yet to be conducted. Heat shock proteins (Hsps) are the well characterized stress inducible proteins playing as molecular chaperones in prokaryotes and eukaryotes. We have also identified two differently localized small Hsps: rice chloroplastic and alfalfa mitochondrial Hsps confer tolerance to oxidative and heat stresses in tall fescue and to salinity and arsenic stresses in E. coli, tobacco, and tall fescue, respectively (Lee et al., 2012a; Lee et al., 2012b). Here, we cloned the small Hsp16.9 gene from various heat stress-induced fragments in Siberian wild rye using differentially expressed gene (DEG) analysis. We examined the mRNA expression of EsHsp16.9, in vitro molecular chaperone activity and in vivo stress tolerance by using a prokaryotic system against diverse environmental stresse

Realization of giant magnetoelectricity in helimagnets

We show that low field magnetoelectric (ME) properties of helimagnets Ba0.5Sr1.5Zn2(Fe1-xAlx)12O22 can be efficiently tailored by Al-substitution level. As x increases, the critical magnetic field for switching electric polarization is systematically reduced from ~1 T down to ~1 mT, and the ME susceptibility is greatly enhanced to reach a giant value of 2.0 x 10^4 ps/m at an optimum x = 0.08. We find that control of nontrivial orbital moment in the octahedral Fe sites through the Al-substitution is crucial for fine tuning of magnetic anisotropy and obtaining the conspicuously improved ME characteristics

Electric polarization enhancement in multiferroic CoCr2O4 crystals with Cr-site mixing

Single crystals of multiferroic cobalt chromite Co (Cr2-x Cox) O4 have been grown via several methods to have different Co3+ doping levels (x=0.0, 0.14, and 0.18). Under magnetic fields, all the crystals display electric polarization reversal below their spiral spin ordering temperatures. We find that both saturated electric polarization and magnetization under magnetic fields increase significantly with the increase in x. This result can be qualitatively explained by a broken balance between at least two electric polarization contributions existing in CoCr2 O4 and is expected to be useful in tailoring electric polarization in similar kinds of multiferroics. © 2009 American Institute of Physics.open222

Could real-time ultrasonography guidance be useful for the effective deployment of FemoSeal in common femoral arteriotomy?

A vascular closure device is used for hemostasis after a procedure involving an arterial puncture. The increasing frequency of endovascular arterial interventions has caused these devices to play a more important role in clinical practice. FemoSeal is a popular vascular closure device, and its safety and effectiveness have been verified. However, complications still occur in some cases, including even disastrous complications on occasion. Even with little experience, it is possible to reduce the complication rate by using real-time ultrasonography monitoring during the deployment of this device. Based on our experiences, presented herein, we suggest that complications related to FemoSeal could be reduced by using our method