Metabolomic profiling in kidney cells treated with a sodium glucose-cotransporter 2 inhibitor.

We aimed to determine the metabolomic profile of kidney cells under high glucose conditions and following sodium-glucose cotransporter 2 (SGLT2) inhibitor treatment. Targeted metabolomics using the Absolute IDQ-p180 kit was applied to quantify metabolites in kidney cells stimulated with high glucose (25 and 50 mM) and treated with SGLT2 inhibitor, dapagliflozin (2 µM). Primary cultured human tubular epithelial cells and podocytes were used to identify the metabolomic profile in high glucose conditions following dapagliflozin treatment. The levels of asparagine, PC ae C34:1, and PC ae C36:2 were elevated in tubular epithelial cells stimulated with 50 mM glucose and were significantly decreased after 2 µM dapagliflozin treatment. The level of PC aa C32:0 was significantly decreased after 50 mM glucose treatment compared with the control, and its level was significantly increased after dapagliflozin treatment in podocytes. The metabolism of glutathione, asparagine and proline was significantly changed in tubular epithelial cells under high-glucose stimulation. And the pathway analysis showed that aminoacyl-tRNA biosynthesis, arginine and proline metabolism, glutathione metabolism, valine, leucine and isoleucine biosynthesis, phenylalanine, tyrosine, and tryptophan biosynthesis, beta-alanine metabolism, phenylalanine metabolism, arginine biosynthesis, alanine, aspartate and glutamate metabolism, glycine, serine and threonine metabolism were altered in tubular epithelial cells after dapagliflozin treatment following 50 mM glucose compared to those treated with 50 mM glucose.

Exploiting elastic buckling of high-strength gold nanowire toward stable electrical probing.

Buckling is a loss of structural stability. It occurs in long slender structures or thin plate structures which is subjected to compressive forces. For the structural materials, such a sudden change in shape has been considered to be avoided. In this study, we utilize the Au nanowire's buckling instability for the electrical measurement. We confirmed that the high-strength single crystalline Au nanowire with an aspect ratio of 150 and 230-nm-diameter shows classical Euler buckling under constant compressive force without failure. The buckling instability enables stable contact between the Au nanowire and the substrate without any damage. Clearly, the in situ electrical measurement shows a transition of the contact resistance between the nanowire and the substrate from the Sharvin (ballistic limit) mode to the Holm (Ohmic) mode during deformation, enabling reliable electrical measurements. This study suggests Au nanowire probes exhibiting structural instability to ensure stable and precise electrical measurements at the nanoscale.

Synaptic Current Response of a Liquid Ga Electrode via a Surface Electrochemical Redox Reaction in a NaOH Solution.

An ionic device using a liquid Ga electrode in a 1 M NaOH solution is proposed to generate artificial neural spike signals. The oxidation and reduction at the liquid Ga surface were investigated for different bias voltages at 50 °C. When the positive sweep voltage from the starting voltage (V S) of 1 V was applied to the Ga electrode, the oxidation current flowed immediately and decreased exponentially with time. The spike and decay current behavior resembled the polarization and depolarization at the influx and extrusion of Ca2+ in biological synapses. Different average decay times of ∼81 and ∼310 ms were implemented for V S of -2 and -5 V, respectively, to mimic the synaptic responses to short- and long-term plasticity; these decay states can be exploited for application in binary electrochemical memory devices. The oxidation mechanism of liquid Ga was studied. The differences in Ga ion concentration due to V S led to differences in oxidation behavior. Our device is beneficial for the organ cell-machine interface system because liquid Ga is biocompatible and flexible; thus, it can be applied in biocompatible and flexible neuromorphic device development for neuroprosthetics, human cell-machine interface formation, and personal health care monitoring.

Closed atraumatic complete rupture of the flexor halluces longus tendon during forward lunge exercise: A case report.

RATIONALE: Acute rupture of the flexor halluces longus (FHL) tendon due to trauma or laceration is a well-known phenomenon. Partial rupture of the FHL tendon caused by tendinitis or stenosing tenosynovitis is common in ballet dancers and athletes. However, atraumatic complete rupture of the FHL is rare: as of 2018, only 7 cases of closed atraumatic complete rupture of the FHL tendon have been reported in the literature. Here, we report on a patient who presented with a closed atraumatic complete rupture of the FHL tendon during a forward lunge exercise. PATIENT CONCERNS: A 35-year-old female visited the clinic with pain in the plantar medial aspect of the left foot, along with weakness and loss of great toe flexion. The patient had a normal foot structure and no history of trauma or systemic disease. She performed a forward lunge exercise more than 50 times on 1 leg per day, more than once a week to strengthen her leg muscles. She reported that she felt a slight pain in her left, great toe while exercising for 3 weeks prior to her visit. One week prior to presentation, severe pain occurred suddenly when her left hallux dorsiflexed strongly during an anterior lunge exercise motion. DIAGNOSIS: Magnetic resonance imaging revealed complete rupture of the FHL tendon near the level of the metatarsal head and neck junction. The lesion was prolonged, with the proximal end displaced to the metatarsal shaft region. INTERVENTIONS: Complete rupture of the FHL tendon was treated with a primary suture. OUTCOMES: At the 1-year follow-up, active plantar flexion of the interphalangeal joint was possible but joint function had a range of 0° to 25°. Flexion strength was reduced slightly, measuring about 70% when compared to the contralateral side, but flexion strength of the metatarsophalangeal joint was normal. LESSONS: We describe an extremely rare case of complete rupture of the FHL tendon at the level of metatarsal head and neck junction. It should be understood that this injury can occur not only in professional athletes but also in the general public, and we recommend educating personal trainers on how to prevent it.

Effect of Fluoride Ions on Wet Etching of Copper/ Molybdenum in Hydrogen Peroxide Solution.

Copper metallization is a key issue for high performance thin film transistor technology. Hydrogen peroxide-based copper etchants are widely used in copper metallization. Recently, a hydrogen peroxide-based copper etchant for a copper/molybdenum double layer was investigated for its versatile use in both amorphous silicon TFTs and in metal-oxide TFTs. However, little is known about the etching mechanism for molybdenum and copper in a hydrogen peroxide solution containing fluorine ions. In this paper, it is shown that the amount of fluorine ions in the hydrogen peroxide-based copper etchant plays an important role in controlling the galvanic reaction between the copper and the molybdenum. A new mechanism of molybdenum dissolution in the presence of fluoride ions in 1.5 M hydrogen peroxide solution is suggested. The concentration of the fluoride ions is also important in eliminating the residue of molybdenum after wet patterning.

Investigation of Blood Flow During Intermittent Pneumatic Compression and Proposal of a New Compression Protocol.

INTRODUCTION: Intermittent pneumatic compression (IPC) is now a widely used therapy for the prophylaxis of deep vein thrombosis and pulmonary embolism. In general, the IPC sequence is composed of sequential compression and simultaneous deflation. Typically, veins are considered to be squeezed and emptied during the compression phase and to be refilled during the deflation phase. However, because the stop or sudden increase in blood flow can be dangerous, a further investigation is needed with respect to the blood flow. MATERIALS AND METHODS: We demonstrated a new compression protocol based on the investigation results of venous blood flow during IPC. This new compression protocol involves successive compression without the deflation phase; thus, the expelled blood volume flow during a given period can be maximized. To investigate the blood flow during IPC, sonography movie clips and in-laboratory developed blood flow analysis software was used. RESULTS: The increases in the peak volume flow during IPC were 49% (±24%) and 25% (±29%) with the conventional protocol and the new protocol, respectively, whereas the total volume flow (TVF) was not significantly changed (-1.0% and -13.0%, respectively). With the new protocol, the peak velocity (PV) was 49% lower than that with the conventional protocol. Thus, the new protocol has an effect of maintaining TVF without resulting in a sudden large increase or decrease in PV. CONCLUSION: The new suggested protocol might improve safety because it can maintain the stability of blood flow by reducing the risk of blood stasis and a rapid change in blood flow.

Ultrafast Sodiation of Single-Crystalline Sn Anodes.

Sodiation was performed on crystalline Sn cylinders using an in situ electron microscope to evaluate the rate performance of the Sn anode by directly measuring the sodiation rate. We observed that the sodiation rate of the Sn anode is more than 2 orders of magnitude higher than the lithiation rate of the Si anode under the same conditions. This unprecedented rate displayed by the Na-Sn system is attributed to the bond characteristics and crystalline-to-amorphous transformation of the Sn crystal at the thin interface of the Na-Sn diffusion couple. Here, using atomic simulations, we explain how and why the Sn anode exhibits this high rate performance by resolving the diffusion process of Na ions in the Na-Sn interfacial region and the electron structure of the crystalline Sn. This work provides a useful insight into the use of Sn as an attractive anode material for realizing ultrafast-charging batteries for electric vehicles and mobile devices.

Natural orifice transluminal endoscopic surgery with a snake-mechanism using a movable pulley.

BACKGROUND: Natural orifice transluminal endoscopic surgery is an emerging technique. We aimed to develop an advanced surgical robot mechanism for natural orifice surgery. METHODS: We propose the active-controlled overtube-type platform with multiple channels for an endoscopic camera and surgical tools. To make such a platform, we suggest an advanced snake mechanism comprising movable pulleys to make a snake mechanism with multiple degrees of freedom and high operating force. RESULTS: The stiffness and maneuverability of the active-controlled platform appeared satisfactory. Using prototypes and ex vivo experiments, we confirmed that the mechanism was suitable for a snake-like robotic platform for natural orifice surgery. CONCLUSIONS: The suggested snake mechanism using movable pulleys has the advantages of stiffness and maneuverability. This new mechanism can be an alternative platform for natural orifice surgery.

Development of a control algorithm for the ultrasound scanning robot (NCCUSR) using ultrasound image and force feedback.

BACKGROUND: Clinicians who frequently perform ultrasound scanning procedures often suffer from musculoskeletal disorders, arthritis, and myalgias. To minimize their occurrence and to assist clinicians, ultrasound scanning robots have been developed worldwide. Although, to date, there is still no commercially available ultrasound scanning robot, many control methods have been suggested and researched. These control algorithms are either image based or force based. If the ultrasound scanning robot control algorithm was a combination of the two algorithms, it could benefit from the advantage of each one. However, there are no existing control methods for ultrasound scanning robots that combine force control and image analysis. Therefore, in this work, a control algorithm is developed for an ultrasound scanning robot using force feedback and ultrasound image analysis. METHODS: A manipulator-type ultrasound scanning robot named 'NCCUSR' is developed and a control algorithm for this robot is suggested and verified. First, conventional hybrid position-force control is implemented for the robot and the hybrid position-force control algorithm is combined with ultrasound image analysis to fully control the robot. The control method is verified using a thyroid phantom. RESULTS: It was found that the proposed algorithm can be applied to control the ultrasound scanning robot and experimental outcomes suggest that the images acquired using the proposed control method can yield a rating score that is equivalent to images acquired directly by the clinicians. CONCLUSIONS: The proposed control method can be applied to control the ultrasound scanning robot. However, more work must be completed to verify the proposed control method in order to become clinically feasible. Copyright © 2016 John Wiley & Sons, Ltd.

Impedance and admittance control for respiratory-motion compensation during robotic needle insertion - a preliminary test.

BACKGROUND: Many robotic needle-biopsy systems have been developed to enhance the accuracy of needle-biopsy intervention. These systems can reduce the intervention time and the radiation exposure of clinicians. However, respiratory-motion compensation is needed to ensure the accuracy and efficiency of needle biopsy intervention. METHODS: Human respiratory-motion data were acquired using three inertial measurement units (IMUs), and respiratory motion was simulated using the Stewart-Gough platform. Robotic needle intervention was performed using impedance and admittance control algorithms for respiratory-motion compensation using the Stewart-Gough platform and a gelatin phantom. RESULTS: The impedance and admittance control algorithms can be used to compensate for respiratory motion during robotic needle insertion. The admittance control algorithm exhibits better performance than the impedance control algorithm. CONCLUSIONS: The impedance and admittance control algorithms can be applied for respiratory-motion compensation during robotic needle insertion. However, further study is needed for them to become clinically feasible.

Ultrahigh Tensile Strength Nanowires with a Ni/Ni-Au Multilayer Nanocrystalline Structure.

Superior mechanical properties of nanolayered structures have attracted great interest recently. However, previously fabricated multilayer metallic nanostructures have high strength under compressive load but never reached such high strength under tensile loads. Here, we report that our microalloying-based electrodeposition method creates a strong and stable Ni/Ni-Au multilayer nanocrystalline structure by incorporating Au atoms that makes nickel nanowires (NWs) strongest ever under tensile loads even with diameters exceeding 200 nm. When the layer thickness is reduced to 10 nm, the tensile strength reaches the unprecedentedly high 7.4 GPa, approximately 10 times that of metal NWs with similar diameters, and exceeding that of most metal nanostructures previously reported at any scale.

Anomalous Stagewise Lithiation of Gold-Coated Silicon Nanowires: A Combined In Situ Characterization and First-Principles Study.

Through a combined density functional theory and in situ scanning electron microscopy study, the effects of presence of gold (Au) spreading on the lithiation process of silicon nanowire (SiNW) were systematically examined. Different from a pristine SiNW, an Au-coated SiNW (Au-SiNW) is lithiated in three distinct stages; Li atoms are found to be incorporated preferentially in the Au shell, whereas the thin AuSi interface layer may serve as a facile diffusion path along the nanowire axial direction, followed by the prompt lithiation of the Si core in the radial direction. The underlying mechanism of the intriguing stagewise lithiation behavior is explained through our theoretical analysis, which appears well-aligned with the experimental evidence.

Vision-based variable impedance control with oscillation observer for respiratory motion compensation during robotic needle insertion: a preliminary test.

BACKGROUND: To reduce the radiation exposure of patients and physicians during needle-based procedures, robotic needle insertion systems have been widely developed. However, during robotic needle insertion, the respiratory motion of the patient can cause serious injury. METHODS: A vision-based variable impedance control algorithm was introduced to compensate for the respiratory motion. The algorithm controls the robot so that the applied forces and moments on the needle are zero. Also, an oscillation observer was introduced to ensure patient safety. A preliminary test was performed using a seven degrees of freedom (7-DOF) robot and a phantom. RESULT: It was found that the proposed algorithm greatly decreases damage to the phantom due to respiratory motion. Also, the proposed oscillation observer was able to ensure robot stability. CONCLUSIONS: The proposed control scheme allows the robot to compensate for the respiratory motion to ensure patient safety during a needle-based procedure.

An Investigation of Gate Pulse Induced Degradation in a-InGaZnO Thin Film Transistors.

We investigated the effects of pulsed gate bias on degradation of amorphous indium gallium zinc oxide (a-InGaZnO) thin film transistors (TFTs). The waveform composed of 0 V and 20 V produced little degradation, but the waveform composed of -20 V and 0 V produced a considerable degradation on the turn-on current in the transfer characteristics. Those instabilities were found mostly in TFTs of which the concentration of Zn is higher than the other metallic components (In, Ga). In order to explain the anomalous degradation behaviors, we propose a possible degradation model which is different from the conventional model of charge trapping. Our proposed model is related to an increase of acceptor-like states in a-InGaZnO near the source and drain electrodes. More electrons can be trapped there, and the increased potential barrier hinders current flow in the channel. The proposed model can also account for the increased frequency dispersion in C-V characteristics of our a-InGaZnO TFTs after the waveform stress.

The Electrochemical Behavior of Mo-Ta Alloy in Phosphoric Acid Solution for TFT-LCD Application.

Molybdenum-tantalum alloy thin film is a suitable material for the higher corrosion resistance and low resistivity for gate and data metal lines. In this study, Mo-Ta alloy thin films were prepared by using a DC magnetron co-sputtering system on a glass substrate. An abrupt increase in the etching rates of low Mo-Ta alloys was observed. From the observed impedance analysis, the defect densities in the MoTa oxide films increased from 5.4 x 10(21) (cm(-3)) to 8.02 x 10(21) (cm(-3)) up to the 6 at% of tantalum level; and above the 6 at% of tantalum level, the defect densities decreased. This electrochemical behavior is explained by the mechanical instability of the MoTa oxide film.

Effects of Chlorine Ions on the Dissolution Mechanism of Cu Thin Film in Phosphoric Acid Based Solution.

The dissolution mechanisms of Cu thin film were studied with a focus on the effect of chlorine ion concentrations in mixture solutions of phosphoric and nitric acid. The dissolution behaviors of Cu thin film were investigated by using potentio-dynamic curves and impedance spectroscopy with varying chlorine ion concentrations. The copper dissolution rate decreased and as a result of this change, CuCl, salt films formed on the Cu surface in the presence of chlorine ions in the mixture solution. Such behavior was interpreted as being competitive adsorption between chlorine and nitrate ions on the copper surface. The passive oxide film on the Cu surface was further investigated in detail using X-ray photoelectron spectroscopy in both the absence and presence of differing chlorine ion concentrations.

Atomic Layer Deposition of Ru Thin Films Using a New Beta-Diketonate Ru Precursor and NH3 Plasma as a Reactant.

Ruthenium (Ru) thin films were grown on thermally-grown SiO2 substrates by plasma enhanced atomic layer deposition (PEALD) using a sequential supply of a new betadiketonate Ru metallorganic precursor, dicarbonyl-bis(5-methyl-2,4-hexanediketonato) Ru(II) (C16H22O6Ru) with a high vapor pressure and NH3 plasma as a reactant at the substrate temperature ranging from 175 and 310 degrees C. A self-limited film growth was confirmed at the deposition temperature of 225 degrees C and the growth rate was 0.063 nm/cycle on the SiO2 substrate with very short number of incubation cycles (approximately 10 cycles). The resistivity of PEALD-Ru films was dependent on the microstructural features characterized by grain size and crystallinity, which could be controlled by varying the deposition temperature. Ru film with the resistivity of -20 µΩ-cm and high density of 11.5 g/cm3 was obtained at the deposition temperature as low as 225 degrees C. It formed polycrystalline structure with hexagonal-close-packed phase that was confirmed by X-ray diffractometry and transmission electronic microscopy analysis. Step coverage of PEALD-Ru film deposited with the optimum condition was good (-75%) at the very small-sized trench (aspect ratio: -4.5 and the top opening size of 25 nm).

Simulation for Large-Area, Inductively-Coupled Plasma Systems Using an Ar/Cl2 Gas Mixture.

As research and development of high-performance devices are becoming increasingly important in the flat panel display industry, new structures and processes are essential to improve the performance of the TFT backplane. Also, high-density plasma systems are needed for new device fabrications. Chlorine-based, inductively-coupled plasma systems are widely used for highly-selective, anisotropic etching of polysilicon layers. In this paper, a plasma simulation for a large-area ICP system (8th glass size and 9 planar antenna set) was conducted using Ar/Cl2 gas. Transport models and Maxwell Equations were applied to calculate the plasma parameters such as electron density, electron temperature and electric potential. In addition, the spatial distribution of ions such as Ar+, Cl2+, Cl-, Cl+ were investigated respectively.

A Study on the Adhesion Properties of Reactive Sputtered Molybdenum Thin Films with Nitrogen Gas on Polyimide Substrate as a Cu Barrier Layer.

NiCr, Mo, and Mo-N thin copper diffusion barrier films are deposited on 200 um thick polyimide films spin-coated on glass substrates by dc reactive magnetron sputtering. The adhesion forces for three systems are measured by micro-scratch test analysis depending on oxygen plasma pretreatment, sputtering power density, moisture contents, and post annealing treatment. The values of adhesion forces for the three systems are linearly proportional to the oxygen plasma treatment time. As deposition power density increases, measured adhesion forces also increase. The existence of moisture adsorbed in the polymer substrate prior to initiating the sputtering process significantly reduces the adhesion force for all systems. Post annealing treatment at 150 degrees C for 12 hours after sputtering also deteriorates the adhesion between the barrier films and polymer substrate. Auger electron spectroscopy reveals that adhesion forces are significantly dependent on the types of compounds formed at the barrier layer/polymer interface. Changes in the adhesion properties of the MoN system as a function of the nitrogen content are explained in terms of the mechanical stability of the MoN(x)O(y) interface layer on the polymer substrate.

Negative gate bias and light illumination-induced hump in amorphous InGaZnO thin film transistor.

While observing the transfer characteristics of a-IGZO TFTs, it was noticed that a hump occurred in the subthreshold regime after light and bias stress. This study analyzes the mechanism of the hump occurrence. It was determined that hump characteristics were related with parasitic TFTs which formed at the peripheral edges parallel with the channel direction. It seems that the negative shift of the transfer characteristics of parasitic TFTs was larger than that of the main TFT under light and bias stress. Therefore, the difference in the negative shift between the main TFT and the parasitic TFT was the origin of the hump occurrence. We investigated the instability of a-IGZO TFTs under negative gate bias with light illumination for various channel structures in order to verify the above mechanism.