Degree Sign Research Articles

Pharmacokinetics of panobinostat: Inter-species difference in metabolic stability.

Panobinostat is a potent pan-HDAC inhibitor that has been tested in multiple studies for the treatment of brain tumors. There have been contrasting views surrounding its efficacy for the treatment of tumors in the CNS following systemic administration when examined in different models or species. We conducted experiments using three different mouse strains or genotypes to have a more comprehensive understanding of the systemic as well as the CNS distributional kinetics of panobinostat. Our study found that panobinostat experienced rapid degradation in vitro in FVB mouse matrices and a faster degradation rate was observed at 37{degree sign}C compared with room temperature and 4{degree sign}C, suggesting that the in vitro instability of panobinostat was due to enzymatic metabolism. Panobinostat also showed inter-strain and inter-species differences in the in vitro plasma stability; and was stable in human plasma. The objective of this study was to examine the in vitro metabolic stability of panobinostat in different matrices and assess the influence of that metabolic stability on the in vivo pharmacokinetics and CNS delivery of panobinostat. Importantly, the plasma stability in various mouse strains was not reflected in the in vivo systemic pharmacokinetic behavior of panobinostat. Several hypotheses arise from this finding, including: the binding of panobinostat to red blood cells, the existence of competing endogenous compounds to enzyme(s), the distribution into tissues with a lower level of enzymatic activity or the metabolism occurring in the plasma is a small fraction of the total metabolism in vivo Significance Statement Panobinostat showed different in vitro degradation in plasma from different mouse strains and genotypes. However, despite the differences surrounding in vitro plasma stability, panobinostat showed similar in vivo pharmacokinetic behavior in different mouse models. This suggests that the inter-strain difference in enzymatic activity did not affect the in vivo pharmacokinetic behavior of panobinostat and its CNS distribution in mice. This lack of translation between in vitro metabolism assays and in vivo disposition can confound drug development.

Impact of Catheter Contact Angle on Lesion Formation and Durability of Pulmonary Vein Isolation

Objectives: This study aimed to evaluate the impact of catheter contact angle on lesion formation and durability of pulmonary vein isolation (PVI). Background: Little is known on the effect of catheter contact angle on lesion formation and durability of PVI. Methods: Both in vitro experiment and retrospective observational study were conducted. For in vitro experiment, radiofrequency lesions were created on explanted swine hearts in three different catheter contact angles (0{degree sign}, 45{degree sign}, and 90{degree sign}). In the retrospective observational study, we assessed patients who had undergone repeat catheter ablation due to atrial fibrillation recurrence after initial PVI. When pulmonary vein (PV) reconnection was observed, we analyzed the previous ablation points within and without the gap area. The gap areas were where ablation had changed the PV activation sequence or eliminated the PV potential in the repeat session. Results: In the in vitro experiment, lesion width was the smallest (5.3 {plus minus} 0.4 mm) in perpendicular contact compared to 0{degree sign} (vs 5.8 {plus minus} 0.5 mm, p=0.040) and 45{degree sign} (vs 6.4 {plus minus} 0.4 mm, p<0.001). In the retrospective observational study, we assessed 666 tags of 16 patients with PV reconnections, and 60 tags were in the gap area. Tags in the gap area had longer interlesion distance (odds ratio [OR] 1.49, p < 0.001), greater contact force variability (OR 1.03, p = 0.008), and higher rate of perpendicular contact (OR 3.26, p < 0.001) on multivariate analysis. Conclusion:Perpendicular contact was associated with a smaller lesion and higher rate of PV reconnection

ЛІНГВОКУЛЬТУРНА СЕМАНТИКА ОРГАНОЛЕПТИВІВ У ГЛЮТОНІЧНОМУ ФРЕЙМІ

In the article S.M. Rudenko made an attempt of a comprehensive study of linguocultural semantics of terminal organoleptics – language signs of the peripheral zone of the gluttonic frame, which are a mental analogue of the perceptual characteristics of units of its nuclear zone. Folklore, ethnographic, ethnolinguistic, lexicographic and popular science sources were taken as a material for research. It is emphasized that in order to denote taste reception, modern Ukrainian language has a wide range of absolutely different units – from word to text. The main representatives of the analyzed case are the nominations of taste, smell, appearance, color, design of dishes and products, however, units representing sound, touch, and consistency also play an important role in describing food perception. Their semantics has cultural characteristics. In the course of the study, it was found that semantic features were invested in a special form of expression such as taste sensation, intensity (degree sign of the degree of manifestation or influence of taste omissions), assessment (positive or negative characteristic of taste sensations in terms of personal, subjective criteria; the presence or lack of evidence); syncretism (indivisibility) of sensory perception of taste and tactile sensations, taste and smell. Phraseological units of the Ukrainian language, which include gustative elements, are used not only in the language of gluttony, but also in the process of nominating the concepts of other areas of human activity, in particular the highest emotional. Text units, which reflect the model of color matching of dishes to the consumer’s taste expectations are of great importance. The obtained results make it possible to make a conclusion that the semantics of organoleptics in the gluttonic frame reflect both taste preferences developed over the centuries-old history of the Ukrainian people and its specific worldview character.

Modeling the distribution of circular polarization degree of microwave emission along the flare loops in event July 19, 2012

The distribution of the degree of circular polarization of microwave emission along the solar flare loops during the event on July 19, 2012, was analyzed with the use of data from the Nobeyama Radioheliograph (NoRH). It was found that the polarization degree in the loop footpoints remains negative (R–L 0 ) and also does not change over time. In the northern and southern legs of the loop, the polarization degree sign changes over time. The proposed explanation of this effect is based on modeling the kinetics of nonthermal electrons and the calculation of their gyrosynchrotron (GS) emission for the model loop located on the solar limb. It was shown that the observed change in the polarization sign in the event on July 19, 2012, can be caused by the presence of longitudinal anisotropy of energy electrons at the upper part of the flare loop.

Study Thermal Stability of Silicate Olivine Cathode Materials with and without Coating

In this research, oxygen release from Li2MnSiO4, Li2Mn0.5Fe0.5SiO4, and chemically delithiated Li2Mn0.5Fe0.5SiO4 at temperatures up to 800{degree sign}C was studied by thermogravimetric analysis (TGA). The results show that the silicate cathode materials release less oxygen (< 4 % weight loss up to 800{degree sign}C) at high temperatures than other cathode materials including LiFePO4, 5%; LiMnPO4, 7%; LiCoO2, 6%, and NCA, 22%. Limited DSC studies on carbon-coated Li2Mn0.5Fe0.5SiO4 show that after 45 cycles at 1/16C rate, the fully charged Li2-xMn0.5Fe0.5SiO4 in presence of electrolyte releases more heat at lower temperatures in comparison to published data on Li2-xMnSiO4 and Li2-xFeSiO4.

Novel Core/Shell Ni@NiO/Pt as High Efficient Electrocatalyst for Alkaline Direct Ethanol Fuel Cells

A one-dimensional core/shell hybrid electrocatalyst for alkaline direct ethanol fuel cells (ADEFC) has been fabricated using Ni@NiO nanowire arrays (NWA) as a novel support for porous Pt nanoparticles (Pt NP). The Ni@NiO NWA has been fabricated by direct electrodeposition inside a polycarbonate template and the subsequent conversion of the outer shell of Ni into an oxide by oxygen plasma annealing. The Pt NP have been deposited onto the Ni@NiO NWA surface by the borohydride technique. Transmission electron microscopy (TEM) has shown that the PtNP contain a homogeneous distribution of fine pores. The electro-catalytic activity for the electro-oxidation of ethanol in alkaline media for Ni@NiO NWA/Pt has been found to be 126 mA/cm2. Chronoamperometry has been used to show that the Ni@NiO NWA/Pt electrocatalyst exhibits favorable stability and activity as well as tolerance to CO-like poisoning during ethanol electro-oxidation at temperatures of 21{degree sign}C and 50 {degree sign}C. The Ni@NiO NWA/Pt electrocatalyst is a potential candidate to replace the commercial Pt/C NP anode electrocatalysts currently used in ADEFC.

Enhanced Oxygen Reduction Kinetics and Durability in PEMFCs at 120{degree sign}C and Low Relative Humidity Using Silicotungstic Acid

Silicotungstic acid (STA), a heteropolyacid, was added to the electrode of polymer electrolyte membrane fuel cells (PEMFCs) and evaluated for increased performance at high temperature and low relative humidity (RHs). Activity at 120{degree sign}C/35%RH was shown to increase by as much as 36% for cells dipped in STA compared to cells dipped in deionized water. Additionally, membrane resistance was improved by 28%. The performance impact of STA was extended out to higher current densities showing a significant improvement in cell performance.

2D Electro-Optic Scanner

In this paper, we present the design and fabrication of a 2D beam steering device using cascaded prism and grating deflectors. The device, based on a single prism with a maximum deflection angle of 5.6{degree sign}, is able to achieve a maximum deflection angle of 29.2o for the cascaded three-prism stage design in the horizontal direction, a 4.6o deflection angle from the grating stage in the vertical direction, and a collimated 4µm beam diameter profile.

Synthesis and Electrochemical Properties of Novel Co2+/Co3+ Layered Ordered Rock-Salt Structure Type Li0.75Ca0.25CoO¬2

New layered transition metal oxide cathode material, Li0.75Ca0.25CoO2 (Space Group = P63/mmc; a = 2.817 Å, b = 2.817 Å, c = 10.79 Å ß = 120{degree sign}) was prepared by a multistep synthetic technique. Electrochemical cycling of 0.75 Li+ per formula unit utilizes both the Co3+/Co4+ and Co2+/Co3+ redox couples. The presence of Ca2+ between CoO2 layers results in low volume difference (~0.8%) between fully lithiated and delithiated materials.

Effect of Preparation Methods on the Properties of Ni-YSZ Cermets for SOFC Anodes

Three methods were applied to prepare Ni-YSZ (Yttria-stabilized zirconia) anode cermets: NiO coating YSZ, YSZ coating NiO and mechanical mixing of NiO-YSZ powders. And finally they were reduced by H2. The structure and sintering properties of the cermets were characterized using TG-DSC, XRD, TEM, EDS and 4-probe direct-current (4-DC) conductivity measurements, respectively. Disk type of solid oxide fuel cells (SOFCs) LSSM-YSZ|YSZ|Ni-YSZ were prepared by a co-pressing method with the above three kinds of anodes. The results show that, the crystalline of all the three anode materials is composites of cubic fluorite YSZ and cubic NiO cermets, among which NiO-coated YSZ has the highest density, the lowest porosity, the highest electrical conductivity (e.g. 14,000 S/cm) and the lowest ionic conductivity. The SOFC prepared with NiO-coated YSZ anode exhibits the highest output performance with a maximum power density of 433 mW cm−2 at 750{degree sign}C fed with H2/air as fuel/oxidant.

Bottom-up Process to Fabricate Periodic Arrays of β-FeSi2 Nanopillars for Photonic Applications

We propose a novel self-assembly process to fabricate periodic arrays of β-FeSi2 nanopillars for photonic applications. Self-assembled monolayers of polystyrene nanospheres (PSNSs) are coated with SiO2 by oblique evaporation at a deposition angle of 70{degree sign}. After the PSNSs are removed by annealing in air at 650 {degree sign}C, periodic arrays of SiO2 nanospherical crowns (NSCs) remain. On the NSC template, Si and Fe are deposited alternatively at a deposition angle of 80{degree sign} and a substrate temperature of 470 {degree sign}C. Due to the strong shadowing effect, non-close-packed nanopillar arrays of β-FeSi2 are successfully fabricated. Periodic arrays of β-FeSi2 are useful to manipulate thermal and/or solar radiation.

Alkaline Durable Anion Exchange Membranes Based on Graft-Type Fluoropolymer Films for Hydrazine Hydrate Fuel Cell

Anion exchange membranes (AEMs) having polyvinylimidazolium grafts were synthesized by radiation-induced graft polymerization of N-vinylimidazole (NVIm) or the coplymerizaiton with styrene onto poly(ethylene-co-tetrafluoro-ethylene) (ETFE) film, followed by N-alkylation and ion exchange reactions. The alkaline durability of the membranes was evaluated in 1M KOH at 60 and 80{degree sign}C. The AEM consisting of the homopolymer and copolymer (1:1 molar ratio) grafts (AEM2 and AEM3) with the ion exchange capacity (IEC) of 0.86 and 1.18 mmol g-1 exhibited ionic conductivity of 23 and 63 mS cm-1, respectively. The homopolymer-type AEM2 showed alkaline stability at 60 {degree sign}C for 270 hours, but degraded at 80 {degree sign}C for ca. 150 hours. In contrast, the copolymer-type AEM3 kept its ion conductivity above 10 mS cm-1 in 1M KOH at 80 {degree sign}C for 250 h. The alkylimidazolium group in the copolymer grafts is a promising anion exchange group in AEMs for highly alkaline durable fuel cells.

Nanofiber Electrodes for High Power PEM Fuel Cells

Very high power was produced from membrane-electrode-assemblies (MEAs) with a Nafion 212 membrane and an electrospun nanofiber cathode that were prepared with Johnson-Matthey (JM) HiSpec{trade mark} 4000 catalyst. At a cathode Pt loading of 0.064 mg/cm2, the maximum power density for H2/air fuel cell operation at 80oC and ambient pressure was 538 mW/cm2. Fuel cell operation at two temperatures (60{degree sign}C and 80 {degree sign}C), backpressures up to 2.0 atmospheres, and a variety of gas feed flow rates was investigated. An electrospun cathode with a Pt loading of 0.055 mg/cm2 produced a maximum power density of 906 mW/cm2 at 80{degree sign}C, 2000 sccm fully humidified air, and a backpressure of 2 atm.

Water Distribution in GDL near Optimal Humidification

In order to better understand the two phase properties of the porous GDL, the liquid water pattern and local saturation in the Toray 060 gas diffusion layer (GDL) is visualized in-situ in cells close to the optimal performance point at 80 {degree sign}C by X-ray tomographic microscopy. A recording time of about 10 s is achieved. At the optimal performance point (dew point of reactant gases 74 {degree sign}C) the water volume fraction observed depends on the rib width. A variation of {plus minus} 8 {degree sign}C of the feed gas dew point leads to significant saturation and performance changes. For different current densities the water volume fraction and permeability of the liquid phase of the cathode are determined and analyzed.

Managing Basal Plane Dislocations in SiC: Perspective and Prospects

Conversion of basal plane dislocations (BPDs) to threading edge dislocations in 8 and 4{degree sign} offcut SiC material has been studied in order to eliminate the nucleation source of Shockley-type stacking faults in the active region of bipolar devices. Ex situ and in situ growth interrupts were used to convert BPDs in the 8{degree sign} material, where conversion rates up to 98% were achieved for in situ interrupts in epilayers with doping < 1x1016 cm-3. Complete spontaneous conversion of BPDs was found to be possible in 4{degree sign} offcut material after ~ 20 µm of epitaxial growth for both intentionally and unintentionally doped films.

Influence of Thermal Stress and Kinetic Bias Stress on the Electrical Performance of Mixed Oxide Thin Film Transistors

This study discusses thermally activated defects in the channel layer of indium zinc oxide (IZO) thin film transistors (TFTs) under electrical and thermal stress resembling practical stress scenarios. Operating temperatures of 20, 50, and 80 {degree sign}C have been chosen to establish a relation between temperature and failure mechanism. With increasing stress period, acceptor- and donor-like traps contribute towards degrading drain current and subthreshold swing. Low temperature long hour anneal for 12, 24, 36, 48 and 60 hr at 150 {degree sign}C are performed on the TFTs post fabrication to cure the defects formed during fabrication. Structures treated for 48 hr demonstrate high stability under extended kinetic stresses, maintaining a high transistor Ion/Ioff ratio of ~ 108. A physically-based mathematical model discusses the reduction in the density of acceptor-like trap states by 50 % for TFTs treated for 12 hrs, and to insignificant numbers for TFTs treated for 48 hr.

(Invited) The Thermal Budget of Hydrogen-Related Donor Profiles: Diffusion-Limited Activation and Thermal Dissociation

The impact of the thermal budget on hydrogen-related donor profiles in high purity silicon implanted with protons in the MeV energy range is investigated. The appearance of donor profiles is limited to the annealing temperature between 350 {degree sign}C and 500 {degree sign}C. The activation of doping profiles is limited by the diffusion of implanted hydrogen from the end-of-range region throughout the radiation-induced damage. This formation process of profiles is described by a diffusion model with an effective activation energy of 1.2 eV. The hydrogen-related donors are radiation-induced defect complexes decorated by hydrogen. The thermal stability of these donors is limited by dissociation. The deactivation of the doping is modeled by two hydrogen-related donor species with effective dissociation energies of 2.5 eV and 3 eV. The described formation and dissociation mechanisms define upper and lower limits of the post-implantation thermal budget, respectively, for sensible use of proton implantation doping in crystalline Silicon.

Oxygen Reduction Activity of Vapor-Grown Platinum Nanotubes

Supportless platinum nanotubes are synthesized by the decomposition of a platinum acetylacetonate vapor within anodic alumina templates at 210 {degree sign}C. As synthesized, the nanotubes are nanoparticulate aggregates composed of Pt crystallites approximately 3 nm in diameter and with a range of lengths from 1 μm to 20 μm. Annealing treatments result in crystallite growth and morphological evolution of the tubular nanostructures. The oxygen reduction activity of the PtNTs was investigated using the rotating disc electrode method at room temperature. PtNTs annealed at 500 {degree sign}C exhibited a specific activity of 2084 μA/cm2Pt at 0.9 V, a value approaching that of polycrystalline Pt. The electrochemical surface area of the annealed structures was found to be quite low, from 5-10 m2/g, resulting in moderate overall mass activity of up to 177 mA/mgPt.

Low-Temperature Cu-Cu Wafer Bonding

Metal thermo-compression bonding is a process suitable for 3D interconnects applications at wafer level. The process requires typically bonding temperatures of ~400{degree sign}C and high contact pressure applied during bonding. Temperature reduction below such values is required in order to solve some issues regarding wafer-to-wafer misalignment after bonding and to minimize thermo-mechanical stresses. Low-temperature (LT) Cu-Cu wafer bonding was successfully demonstrated at 175{degree sign}C. The bond quality, bond strength, metal interface layers microstructure and chemical composition of Cu-Cu wafer pairs bonded under different process conditions were investigated. Experimental results on various Cu native oxide methods evaluation as well as results obtained for various bonding and annealing temperatures are presented.

High Tensile Strained In-Situ Phosphorus Doped Silicon Epitaxial Film for nMOS Applications

In-situ phosphorus doped silicon epitaxial film with 2.8 X 1021cm-3 doping level is found to show high tensile stress comparable to carbon doped silicon with 1.8% substitutional carbon. As-grown samples show electrically activated dopant concentration of less than 2 X 1020 cm-3. The high tensile and low activation could be well explained by formation of a pseudocubic Si3P4 structure in silicon lattice. Film resistivity of 0.29 mOhm-cm could be obtained with 0.25 ms annealing at 1200 {degree sign}C, with slight reduction in tensile strain. Also, 0.23 mOhm-cm could be obtained by millisecond anneal at 1300 {degree sign}C, but with 30% reduction in tensile strain.