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Objective Atomoxetine and fluoxetine are psychopharmacologic agents associated with loss of appetite and weight. Adenosine monophosphate-activated protein kinase (AMPK) is the cellular energy sensor that regulate metabolism and energy, being activated by fasting and inhibited by feeding in the hypothalamus.Methods Human brain cell lines (SH-SY5Y and U-87 MG cells) were used to study the outcome of atomoxetine and fluoxetine treatment in the activity of AMPK-acetyl-CoA carboxylase (ACC)- carnitine palmitoyl transferase 1 (CPT1) pathway and upstream regulation by calcium/calmodulin-dependent kinase kinase β (CaMKKβ) using immunoblotting and CPT1 enzymatic activity measures.Results Phosphorylation of AMPK and ACC increased significantly after atomoxetine and fluoxetine treatment in the first 30–60 minutes of treatment in the two cell lines. Activation of AMPK and inhibition of ACC was associated with an increase by 5-fold of mitochondrial CPT1 activity. Although the neuronal isoform CPT1C could be detected by immunoblotting, activity was not changed by the drug treatments. In addition, the increase in phospho-AMPK and phospho-ACC expression induced by atomoxetine was abolished by treatment with STO-609, a CaMKKβ inhibitor, indicating that AMPK-ACC-CPT1 pathway is activated through CaMKKβ phosphorylation.Conclusion These findings indicate that at the cellular level atomoxetine and fluoxetine treatments may activate AMPK-ACC-CPT1 pathways through CaMKKβ in human SH-SY5Y and U-87 MG cells.

Supplemental Digital Content is Available in the Text. Acupuncture treatment for 6-month period altered DNA methylation patterns, particularly in the prefrontal cortex, in a mouse model of chronic neuropathic pain., Chronic pain reduces life quality and is an important clinical problem associated with emotional and cognitive dysfunction. Epigenetic regulation of DNA methylation is involved in the induction of abnormal behaviors and pathological gene expression. We examined whether acupuncture can restore epigenetic changes caused by chronic pain, and identified the underlying mechanisms in neuropathic pain mice. Acupuncture treatment for 6 months (3 days/week) improved mechanical/cold allodynia and the emotional/cognitive dysfunction caused by left partial sciatic nerve ligation (PSNL)-induced neuropathic pain. The effects of acupuncture were associated with global DNA methylation recovery in the prefrontal cortex (PFC). Analysis of DNA methylation patterns in PFC indicated that 1364 overlapping genes among 4442 and 4416 methylated genes in the PSNL vs sham and PSNL vs acupuncture points groups, respectively, were highly associated with the DNA methylation process. Acupuncture restored the reduced expression of 5-methylcytosine, methyl-cytosine-phospho-guanine binding protein 2, and DNA methyltransferase family enzymes induced by PSNL in PFC. Methylation levels of Nr4a1 and Chkb associated with mitochondrial dysfunction were decreased in PFC of the PSNL mice, and increased by acupuncture. By contrast, high expression of Nr4a1 and Chkb mRNA in PSNL mice decreased after acupuncture. We also found that acupuncture inhibited the expression of Ras pathway-related genes such as Rasgrp1 and Rassf1. Finally, the expression of Nr4a1, Rasgrp1, Rassf1, and Chkb mRNA increased in the neuronal cells treated with Mecp2 small interfering RNA. These results suggest that acupuncture can relieve chronic pain-induced comorbid conditions by altering DNA methylation of Nr4a1, Rasgrp1, Rassf1, and Chkb in the PFC.

The piezoelectric energy generation properties of transparent flexible devices (TFD) based on PbZr 0.52 Ti 0.48 O 3 (PZT) films, which were fabricated by laser lift-off (LLO) process, were studied for a piezoelectric energy harvester. Through the introduction of indium-tin-oxide (ITO) and polyethylene terephthalate (PET) substrates, TFDs were implemented, respectively. The TFDs based on PZT films generated an AC-type output signal and output power of 8.4 nW/cm 2 , at periodically bending and releasing motion. In addition, inverted output signals were observed when the manufactured TFDs were connected to the measuring equipment in reverse and were bended to the reverse direction, demonstrating that the generating signals originated from the piezoelectric effect of TFDs. The experimental results clearly showed that the TFDs based PZT film have potential for use in next generation of electronic devices applications such as flexible devices, transparent electronics, and energy harvester.

Lead zirconate titanate (PZT) nanotubes fabricated by template-assisted method using sol–gel solution infiltration are applied for energy harvester. To fabricate PZT nanotubes, an anodic aluminum oxide is used for the template, and as-prepared PZT solution dropped on the surface of the AAO is infiltrated by vacuum pump into the pores in the AAO. The template including PZT solution is dried at 80 °C for 1 min and dried again at 300 °C for 10 min, and then it treated at 650 °C for 30 min to anneal PZT and form the expected perovskite phase. The fabricated nanotubes were mixed with PDMS polymer composite and polyimide films coated Pt/Ti were used for electrodes. Finally, it demonstrated that the energy harvester could generate the output power of 37 nW/cm2.

The ferroelectric properties of flexible devices based on 0.05Pb(Al 0.5 Nb 0.5 )O 3 –0.95Pb(Zr 0.52 Ti 0.48 )O 3 + 0.7 wt.%Nb 2 O 5 + 0.5 wt.%MnO 2 (PAN-PZT) thin films, which were fabricated using a laser lift-off (LLO) process, were investigated. The flexible devices based on PAN-PZT thin films were coated with a sacrificial layer, which prevented or minimized damage during LLO process. The structural and electrical properties of the PAN-PZT thin films before and after LLO process demonstrated that the crystallographic and ferroelectric properties of the device were retained after LLO process. Flexible devices based on PAN-PZT thin films coated with a sacrificial layer may be fabricated using the LLO process for the production of flexible electronic devices.

(Ba,Sr)TiO 3 (BST) thin film with a perovskite structure has a potential for the practical applications in various functional devices. Normally, the BST thin films derived from sol–gel and sputtering are amorphous or partially crystalline when processed below 700 °C. For the purpose of integrating BST thin film directly into system-on-package (SoP), it is necessary to process the BST film below 350 °C. The electrical properties of low-temperature crystallized BST film were studied in this paper. The BST thin films have been crystallized at 300 °C by excimer laser annealing (ELA). The BST films were exhibited in a single perovskite phase and have well-defined electrical properties such as high dielectric constant, low dielectric loss and low leakage current density. As a result, we demonstrated crystallized BST thin film which has permittivity of 143, dielectric loss of 0.028 and leakage current density of 0.9 μA/cm 2 below 300 °C.

Bilayer TiOx (oxygen rich, region 1)/TiOy (oxygen poor, region 2) homojunctions were evaluated as resistive switching elements where the TiOx layers were designed with various oxygen contents. Depending on the oxygen ion content, controllable memory windows were observed by changing the off-state (high-resistance state), while the on-state (low resistance) was left with very little change. The cause of the variable memory windows in resistive switching phenomena appears to be the increasing amounts of movable oxygen ions between the TiOx and TiOy layers. In addition, the X-ray photoelectron spectroscopy measurements of the initial, low resistance, and high-resistance states in the homojunctions demonstrated the possible change of metallic and insulating Ti sub-oxide phases at the interfaces and oxygen ion rich region due to the migration of oxygen ions.

Low-temperature-crystallized PbZr 0.52 Ti 0.48 O 3 (PZT) thin films, prepared using a sol-gel method, with a vanadium additive are demonstrated. The low crystallization and melting temperatures of vanadium oxide helped to reduce the crystallization temperature, and improved the grain growth in PZT thin films. Perovskite PZT thin films were obtained at a low annealing temperature of 450°C, and remarkable electrical properties such as a remnant polarization of 4.3 μC/cm 2 , a coercive field of 49.3 kV/cm, a dielectric constant of 585 at 1 MHz, a dielectric loss of 0.022 at 1 MHz, and a tunability of 64.5% were observed. The present results suggest that these low-temperature-crystallized PZT thin films could be used for integrated ferroelectric device applications.

Pt/CoOx/Pt tri-layers exhibited reproducible and stable unipolar switching under a dc sweeping voltage. In order to investigate the role of oxygen reduction in the metal-deficient CoOx layer, resistive switching of the post-annealed CoOx thin film was compared with those of the as-deposited CoOx thin film. X-ray photoemission spectroscopy showed larger reproducible resistance switching and decreasing of current level in the post-annealed CoOx thin film. This may be explained by a reduction in oxygen stoichiometry without phase transformation of the CoOx. In addition, stable switching in post-annealed CoOx layer is considered to originate from the decrease of the Co vacancies in local Co3O4 region partially distributed in the whole CoOx layer, not in the dominant CoO.

The rutile TiO 2 thin film involving two different top electrodes (Pt and Al) clearly shows the unipolar and bipolar resistive switching transitions which are dependent on the degree of redox properties at TiO 2 layer-electrode interfaces. Detailed current level analysis coupled with Auger electron spectroscopy measurements of the Pt/TiO 2 /Pt and Al/TiO 2 /Pt structures in the on/off switching states revealed the implication of oxygen ion migration induced chemical reaction at the Al–TiO 2 interfaces. Therefore, it is expected that the bipolar transition nature of resistive switching with an Al electrode is the resulting formation of a thin AlO x layer due to redox reaction at Al–TiO 2 layer interfaces.

The bipolar resistive switching characteristics in polycrystalline TiO2 thin films after regular forming process were studied using two different top or bottom TiN electrodes (Sample A: top TiN/TiO2/Pt, Sample B: Pt/TiO2/TiN bottom). The sample A and B clearly showed two different switching directions of counter-clockwise (CCW) and clockwise (CW) bipolar switching behaviors, respectively, depending on the relative position of the TiN electrode. These switching characteristics in both samples could be understood by considering the forming and rupture of the conducting path due to the migration of oxygen ions between the TiO2 layer and the TiN electrode, which acts like the oxygen reservoir. In addition, both samples clearly display high reliable memory switching characteristics, such as stable switching speed (μs), endurance behaviors (>104), and long retention times (>104 s).

We systematically investigated the resistive switching properties of thin TiO₂ films on Pt/Ti/SiO₂/Si substrates that were embedded with a Co ultra thin layer. An in-situ sputtering technique was used to grow both films without breaking the chamber vacuum. A stable bipolar switching in the current-voltage curve was clearly observed in TiO₂ films with an embedded Co ultra thin layer, addressing the high and low resistive state under a bias voltage sweep. We propose that the underlying origin involved in the bipolar switching may be attributed to the interface redox reaction between the Co and TiO₂ layers. The improved reproducible switching properties of our novel structures under forward and reverse bias stresses demonstrated the possibility of future non-volatile memory elements in a simple capacitive-like structure.

Metal–oxide–semiconductor structures (MOS) with the embedded Co nanoparticles (NPs) were efficiently fabricated by utilizing an external laser irradiation technique for the application of nonvolatile memory. Images of high resolution transmission electron microscopy measurements exhibited that the Co NPs of 5 nm in diameter were clearly embedded in SiO 2 gate oxide. Capacitance–voltage measurements certainly exhibited flat-band voltage shift of 2.2 V from 2 V to −8 V in sweeping range. The retention characteristics of MOS capacitors with the embedded Co NPs were also studied as a function of tunnel oxide thickness to confirm the suitability of nonvolatile memory devices with metal NPs. The experimental results reveal that our unique laser process will give possible promise for experimental efficient formation or insertion of metal NPs inside the gate oxide.

We report the magnetic behaviors of Fe/sub 3/O/sub 4/ thin films grown by zero field growth (ZFG) and field growth (FG) techniques during the sputtering process. In FG conditions, an in situ 300 Oe field during growth is applied to a substrate, inducing an easy axis of magnetization. Structural observations obtained by high-resolution transmission electron microscopy measurements clearly depicted a significant reduction of the grain boundaries and voids in the Fe/sub 3/O/sub 4/ films grown under FG conditions, thus explaining the saturated magnetization of the Fe/sub 3/O/sub 4/ films at about 0.01 T. This behavior was expected due to a remarkable reduction of the antiferromagnetic exchange couplings between grains for FG conditions. In addition, the zero-field-cooled magnetization of the ZFG samples showed an abrupt change at about 285 K, confirming the existence of defects or other phases in the ZFG films.

Magnetic tunnel junctions (MTJs) with Fe 3 O 4 electrodes were prepared to observe spin- dependent tunneling effect of half-metallic materials through an insulating AlO x barrier at room temperature (RT). In addition, the plasma treatment with Ar gas was in situ performed to improve surface morphology of an as-deposited Fe 3 O 4 electrode. After Ar plasma treatment, the root mean square of as-deposited Fe 3 O 4 thin film was decreased from 4.5 A to 2.5 A. Magnetoresistance (MR) and electrical breakdown voltage of the MTJ were found to be 11% and 0.8 V at RT, respectively. This large MR value is ascribed to the enhanced surface morphology of Fe 3 O 4 electrode after plasma treatment. This MR value at RT gives a potential way of using Fe 3 O 4 thin films in the spintronic devices, together with the enhanced surface treatment technique.

The single-layer 400 μm × 200 μm sized Ba0.6Sr0.4TiO3 thin-film embedded chip capacitors with two external electrodes fabricated on the surface of the chip capacitors have been demonstrated. The structure of the external electrodes placed on the same surface allows the reduction of connection length, resulting in low parasitic loss and noise of elecronic devices. The fabricated chip capacitors exhibited excellent electrical properties such as high capacitance density and dielectric constant (1687 nF/cm2 and 452) and a low dielectric loss of 0.052 at 1 kHz, respectively. In addition, the chip capacitors exhibited the superior temperature stability of X5R (ΔC/C = ±15% at -55°C to +85°C) characteristics. Such a low leakage current density of ~ 0.15 μA/cm2 at 3 V and a high breakdown voltage of 19.75 V were obtained as well. In conclusion, the chip capacitors are suggested as a candidate for the applications of embedded passive components.

We present some unusual spin-polarized transport phenomena in asymmetric double barrier magnetic tunneling junctions (ADBMTJs) with CoFe/AlOx/ferromagnetic nanoparticle (FM-NPs)/AlOx/Ta structures. The conductance curves and the magnetoresistance ratio clearly oscillate with applied bias voltage, indicating the presence of Coulomb blockade effects due to isolated ferromagnetic nanoparticles in the parallel configuration in the ADBMTJ. The oscillation period is about 1.5 mV at 2 K.

In this report, a phenomenon of superparamagnetism through Co nanodots (NDs) prepared by laser irradiation method is studied. These NDs are simply prepared on Si substrates by applying an external laser irradiation on ultra thin Co films at room temperature. The laser irradiation on these ferromagnetic thin films locally melt the film at an extremely shot time so that the melted films get together to form the NDs by the strain effect. Structural properties of these NDs are investigated by scanning electron microscope, atomic force microscope (AFM), and transmission electron microscope (TEM). The magnetization as a function of temperature with differential Co NDs is measured at field cooling (FC) and zero field cooling (ZFC) methods. Results show that at 0.3 T field, remanence magnetization M/sub r/ is saturated. The diameter of Co NDs is increased with an increase temperature of zero remanence value. The zero remanent value at each temperature demonstrates that below this temperature, the magnetic moments are at least partially blocked. In addition, Co NDs have relatively high anisotropy energy because of a field growth method which is the additional source of the anisotropy.

The ferromagnetic quantum dots (FMQDs) are fabricated by exposing a pulsed Nd:YAG laser (wavelength=355 nm) on ultrathin cobalt (Co) films under an external magnetic field of 1000 Oe. Various dot diameters and densities of more than 3.5×1010/cm2 are ultimately realized by changing laser power, scan condition and initial film thickness. In addition, both AlN and Ta thin films as capping layers are used to protect the FMQDs from natural oxidation effect. The observed coercivity values of uncapped and capped FMQDs are changed from 600 up to 200 Oe with the initial Co thickness of 2 nm, respectively. The observation of magnetic force microscopy and hysteresis loops clearly confirms in-plane single domain state for the Ta-capped FMQDs.

Resistance switching phenomena in an amorphous Ni-Ti-O film were investigated. Very clear bipolar resistive switching characteristics were observed with good reproducibility. Stable retention and on/off pulse switching operation was demonstrated. An analysis of x-ray photoelectron spectroscopy of the Ni-Ti-O film provided a clue that the observed unusual bipolar resistance switching in the film is due to a microscopic change in the Ni-O and Ti-O binding states at the Ni-Ti-O film/electrode interface.

We have investigated negative remanence in Co NP system. The Co NPs were uniquely fabricated by using a laser irradiation technique. Magnetization measurements performed on Co NP system show negative remanence taken at temperatures higher than 92 K. The observed negative remanence correlates to the blocking temperature of superparamagnetism. Although we have no clear explanation for negative remanence, this behavior is associated to the magnetic coupling characteristic between the superparamagnetic Co and antiferromagnetic CoO.

We demonstrated a way to fabricate the crystalline Ba0.6Sr0.4TiO3 (BST) thin films using excimer laser annealing technique on the amorphous BST thin films fabricated by sol-gel process. The grain size of the laser-annealed films is larger than that of the conventionally thermal-annealed films. However, an uncrystallized, amorphous layer was observed near the film/substrate interface due to the limited laser absorption depth. The uncrystallized layer has a critical influence on out-of-plane dielectric property of BST films. The significant difference of the relative dielectric permittivity (er) between in-plane (1383) and out-of-plane (184) directions is observed.

Reversible counter-clockwise and clockwise resistive switching in a TiN/TiO2/TiN structure was studied by different polarities of bias voltage. The nature of the bipolar switching phenomenon is related to the creation and annihilation of filament paths caused by redox reactions at locally confined interfaces between the TiO2 layer and TiN electrode. The analysis of electron energy loss spectroscopy (EELS) confirmed the formation of interfacial TiOxN1−x layer between the TiO2 and TiN bottom electrode. The TiOxN1−x layer reduces current levels of ON and OFF states by partially blocking oxygen ion drift to the TiN bottom electrode.

TiO2 (oxygen rich, region 1)/TiO2−x (oxygen poor, region 2) multilayer homojunctions were studied as alternative resistive switching structures for both high and low resistance transitions. Stable bipolar resistive switching characteristics, including stable switching speeds (microseconds) and endurance behaviors, as well as long retention times (>104 s) were demonstrated. The nature of the resistive switching phenomenon in multilayer structures seems to be a combination of the conduction path and the redox reaction, resulting from the oxygen ions drifting between the oxygen rich and poor regions of the multilayer structures. A possible conduction sketch for bipolar switching behaviors is also discussed.

We present experimental results for laser-induced Au nanoparticle (NP) embedded in a HfO2 high-k dielectric matrix. Cross-sectional transmission electron microscopy images showed that the Au NPs of 8nm in diameter were clearly embedded in HfO2 matrix. Capacitance-voltage measurements of Pt∕HfO2∕AuNPs∕HfO2 on p-type Si substrate reliably exhibited metal-oxide-semiconductor behavior with a large flatband shift of 4.7V. In addition, the charge retention time at room temperature was found to exceed 105h. This longer time was attributed to the higher electron barrier height via high work function of the Au NP.

Metal-oxide-semiconductor (MOS) capacitors with Co nanoparticles (Co NPs) were successfully fabricated by utilizing an external laser irradiation method for the application of nonvolatile memory. Experimental images of cross-sectional transmission electron microscopy showed that the Co NPs of 5nm in diameter were clearly embedded in SiO2 layer. Capacitance-voltage measurements of Pt∕SiO2∕Co NPs∕SiO2 on p-type Si (100) substrate certainly exhibited typical MOS behavior with a flatband voltage shift of 1.1V. In addition, the charge retention characteristics of MOS capacitors with the Co NP were investigated using capacitance-time measurements. The present results indicate that their unique laser process gives rise to a possible promise for the efficient formation or insertion of metal NPs inside the MOS structures.

Pseudobilayer HfO2∕HfSixOy gate dielectrics in metal-oxide-semiconductor devices were prepared using an inductively coupled rf plasma sputtering technique. This sputtering method was designed to improve the uniformity and efficiency of formation of high-quality gate dielectrics at room temperature. Crystallization of the gate dielectrics was easily controlled from amorphous to monoclinic by varying the external power from 0to60W at RT. The chemical bond states of the interfacial layers in the as-deposited and postannealed samples were analyzed with an x-ray photoelectron spectroscopy (XPS) system. The XPS results revealed that the interfacial layers of the as-deposited and annealed samples were hafnium silicide and hafnium silicate, respectively. Compared with the as-deposited sample, the pseudobilayer HfO2∕HfSixOy gate dielectric annealed at 750°C yielded excellent electrical characteristics due to the hafnium silicate interfacial layer. The dielectric constant and leakage current of the postannealed sam...

An in situ direct radiation annealing (IDRA) technique on the AlOx insulating barrier was performed to enhance the thermal stability of magnetic tunneling junctions (MTJs). Our method was found to improve the dielectric and structural properties of AlOx insulating barrier in MTJs. After the proper IDRA process, the conventional ex situ annealing process exhibited an additional enhancement of thermal stability by significantly reducing the interdiffusion process between Co80Fe20 electrode and AlOx insulating barriers. Experimentally observed tunneling magnetoresistance of MTJs after the IDRA process showed about 55% up to 350°C. Finally, a surface-plamon resonance spectroscope measurement observed that the dielectric constant of insulating barriers was increased from 2.7 to 3.2 after the IDRA process.