bluuebunny/crossref_metadata_2025 huggingface dataset:
Electroacupuncture Reduces the Dose of Midazolam Monitored by the Bispectral Index in Critically Ill Patients with Mechanical Ventilation: An Exploratory Study
Authors: Zheng Xia , Meng Jian-biao , Fang Qiang
Published: March 2012

Objective

Electroacupuncture, a modern variation on a traditional Chinese treatment, might be useful for sedation and analgesia. This study aims to investigate whether electroacupuncture can modify the dose of midazolam monitored by the bispectral index (BIS) in critically ill patients with mechanical ventilation.

Methods

Orotracheally intubated patients undergoing mechanical ventilation were randomly assigned into three groups (groups A, B and C). All patients were given an intravenous infusion of midazolam. Patients in group A received no additional treatment. Patients in group B were given acupuncture without electrical stimulation at acupuncture points GV24 and EX–HN3 ( Yintang) for 6 h simultaneously, and patients in group C were given electroacupuncture to the same points as in group B.

Results

Maintaining the BIS between 60 and 80, the hourly mean one dose of midazolam within the first 6 h after sedation in group C was 0.05 (±0.02 mg/kg per hour), which was significantly lower than both group A (0.08±0.03 mg/kg per hour, p<0.001) and group B (0.07±0.01 mg/kg per hour, p<0.021). The doses in groups A and B showed no significant difference. Between-group comparison analysis of hepatic and renal function and severe adverse reactions all showed no significant difference between the three groups.

Conclusions

Electroacupuncture appears to reduce markedly the dose of sedative drug required in critically ill patients with mechanical ventilation monitored by BIS, without any obvious severe adverse action, and larger studies to confirm the effect are justified.
Quality control by tissue microarray in immunohistochemistry: Figure 1
Authors: Tripodi Sergio Antonio , Rocca Bruno Jim , Hako Lizart , Barbagli Letizia , Bartolommei Sabrina , Ambrosio Maria Raffaella
Published: March 2012

Aims

An external positive control section is included in each immunohistochemical analysis as a well recognised and validated technique for standardising results. The method is time-consuming and expensive. On the contrary, internal controls are warranted and inexpensive, but their use is only feasible in selected diagnoses. The aim of this work is to show how the method of the authors allows improving the interpretation and cuts costs in the immunohistochemical analysis of bone marrow specimens.

Methods

A paraffin-embedded tonsil tissue cylinder was sampled from a donor block using an automated sampler and included as an ‘internal control’ together with a bone marrow biopsy in a recipient block, avoiding the use of external tonsil tissue control. To validate this technique, the authors compared the quality of immunohistochemistry, the workload and costs with routine external control in 50 consecutive bone marrow biopsies.

Results

Processing simultaneously the sample and the tissue control in the same block, 60 external positive control tests were spared. Only a few minutes were taken for the preparation of the recipient blocks, and no particular technical skill was required. Considering that the volume of antibodies used for the analysis of each sample was not increased, a considerable amount of the disposable material was saved. The workload of technicians was decreased and some potential technical bias was avoided. The time required for pathologists to interpret the slides was also reduced.

Conclusions

In conclusion, this seems to be a feasible, cost-cutting and quality-improving technique, not limited to haematopathology but potentially extensible to other fields of pathology.
Differential expression of TRPM7 in rat hepatoma and embryonic and adult hepatocytes
Authors: Lam D. Hung , Grant Caroline E. , Hill Ceredwyn E.
Published: March 2012

TRPM7 channels are implicated in cellular survival, proliferation, and differentiation. However, a profile of TRPM7 activity in a specific cell type has not been determined from embryonic to terminally differentiated state. Here, we characterized TRPM7 expression in a spectrum of rat liver cells at different developmental stages. Using the whole-cell patch clamp technique, TRPM7-like Na+ currents were identified in RLC-18 cells, a differentiated, proliferating hepatocellular line derived from day 17 embryonic rat liver. Currents were outwardly rectifying, enhanced in divalent-free solutions, and inhibited by intracellular Mg2+. Reverse transcription – polymerase chain reaction (RT–PCR) revealed that RLC-18 cells express both TRPM6 and TRPM7. However, mean currents were reduced almost 80% by 1 mmol/L 2-aminoethoxyphenylborate (2-APB) and were abolished in RLC-18 cells heterologously expressing a dominant negative TRPM7 construct, suggesting that TRPM7 is the major current carrier in these cells. Functional comparison showed that relative to terminally differentiated adult rat hepatocytes, currents were 1.8 and 3.9 times higher in, respectively, RLC-18 and WIF-B cells, a rat hepatoma – human fibroblast cross. Our results demonstrate that plasma membrane TRPM7 channels are more highly expressed in proliferating cells as compared with terminally differentiated and nondividing rat hepatocytes and suggest that downregulation of this channel is associated with hepatocellular differentiation.
Dunn’s index for cluster tendency assessment of pharmacological data sets
Authors: Rivera-Borroto Oscar Miguel , Rabassa-Gutiérrez Mónica , Grau-Ábalo Ricardo del Corazón , Marrero-Ponce Yovani , García-de la Vega José Manuel
Published: March 2012

Cluster tendency assessment is an important stage in cluster analysis. In this sense, a group of promising techniques named visual assessment of tendency (VAT) has emerged in the literature. The presence of clusters can be detected easily through the direct observation of a dark blocks structure along the main diagonal of the intensity image. Alternatively, if the Dunn’s index for a single linkage partition is greater than 1, then it is a good indication of the blocklike structure. In this report, the Dunn’s index is applied as a novel measure of tendency on 8 pharmacological data sets, represented by machine-learning-selected molecular descriptors. In all cases, observed values are less than 1, thus indicating a weak tendency for data to form compact clusters. Other results suggest that there is an increasing relationship between the Dunn’s index as a measure of cluster separability and the classification accuracy of various cluster algorithms tested on the same data sets.
Autoantibodies against cardiac β1-adrenoceptor do not affect the low-affinity state β1-adrenoceptor-mediated inotropy in rat cardiomyocytes
Authors: Abdelkrim Mohammed Amine , Mallem Mohamed Yassine , Chatagnon Gérard , Gogny Marc , Desfontis Jean-Claude , Noireaud Jacques
Published: March 2012

Circulating autoantibodies directed against the 2nd extracellular loop (EL-2) of β1-adrenoceptors (β1-AABs) have been detected in the serum of patients with various cardiovascular pathologies. β1-AABs induce agonistic, positive inotropic effects via β1-adrenoceptors (β1ARs). In the mammalian heart, β1-AR can exist in 2 distinct activated configurations (the so-called high- and low-affinity states). The aim of the present study was to investigate whether the action of β1-AAB is dependent on the affinity state of β1AR in isolated ventricular cardiomyocytes of adult Wistar rats. Immunoglobulin G (IgG) containing β1-AAB obtained from animals immunized with a peptide corresponding to the EL-2 of human β1-AR, caused a dose-dependent increase in cell shortening. Isoproterenol-induced inotropy was significantly reduced in cardiomyocytes that had been preincubated with IgG containing β1-AAB and in cardiomyocytes isolated from immunized rats. The negative effects of preincubation with IgG containing β1-AAB on the response to isoproterenol was inhibited in the presence of bisoprolol. CGP 12177A and pindolol-induced inotropy was not affected by IgG preincubation or immunization. No detectable inotropic effect of cell shortening was obtained with IgG containing β1-AAB in the presence of propranolol and 3-isobutyl-1-methylxanthine. The present study demonstrates that β1-AABs have no agonist/antagonist-like effects upon low-affinity state β1-ARs. This result indicates that β1-AABs recognize and stabilize the high-affinity state, but are unable to stabilize and (or) induce the low-affinity state receptor.
A DERIVATION OF THE BREIT EQUATION FROM BARUT'S COVARIANT FORMULATION OF ELECTRODYNAMICS IN TERMS OF DIRECT INTERACTIONS
Authors: LOUIS-MARTINEZ DOMINGO J.
Published: March 2012

We study Barut's covariant equations describing the electromagnetic interactions between N spin-1/2 particles. In the covariant formulation each particle is described by a Dirac spinor. It is assumed that the interactions between the particles are not mediated by a bosonic field (direct interactions). Within this formulation, using the Lagrangian formalism, we derive the approximate (semirelativistic) Breit equation for two interacting spin-1/2 particles.
COMPARISON OF COLOR AND TEXTURE FOR IRIS RECOGNITION
Authors: BIRGALE LENINA , KOKARE MANESH
Published: March 2012

This paper proposes the utility of texture and color for iris recognition systems. It contributes for improvement of system accuracy with reduced feature vector size of just 1 × 3 and reduction of false acceptance rate (FAR) and false rejection rate (FRR). It avoids the iris normalization process used traditionally in iris recognition systems. Proposed method is compared with the existing methods. Experimental results indicate that the proposed method using only color achieves 99.9993 accuracy, 0.0160 FAR, and 0.0813 FRR. Computational time efficiency achieved is of 947.7 ms.
HIGH-PRESSURE SYNTHESIS AND CHARACTERIZATION OF NEW METASTABLE OXIDES
Authors: ALONSO J. A. , MARTÍNEZ-LOPE M. J. , DE LA CALLE C. , SÁNCHEZ-BENÍTEZ J. , RETUERTO M. , AGUADERO A. , FERNANDEZ-DÍAZ M. T.
Published: March 2012

Many transition-metal oxides in elevated valence states [e.g. Mn(V), Co(IV), Ni(III), Cu(III) ] present a metastable character and, given the difficulty of their synthesis, have been relatively little studied. However, they are very interesting materials presenting strong electronic correlations that are bound to exotic properties such as superconductivity, metal behavior, metal–insulator transitions or colossal magnetoresistance. The metastability of these compounds requires special synthesis conditions such as the application of high pressure. In the last years, we have prepared and investigated a good number of materials belonging to several families such as RNiO3 (R = rare earths), Ba3Mn2O8 , (Ba,Sr)CoO3 , La2(Ni,Co)O4+δ , etc. In the study and correct characterization of these oxides it has been decisive the use of elastic neutron diffraction, most of the times in powder samples. This technique has allowed us to access the structural details typically related to the octahedral tilting in perovskite structures, the oxygen stoichiometry and order–disorder of the oxygen sublattice, the distinction between close elements in the Periodic Table, the resolution of magnetic structures and, in general, the establishment of a correlation between the structure and the properties of interest. This letter is organized around the binomial "high-pressure synthesis" and "characterization by neutron diffraction" and illustrated with some selected examples among the metastable materials above mentioned.
PERFORMANCE OF Ce-INCORPORATED KIT-6 SUPPORTED COBALT CATALYSTS FOR FISCHER–TROPSCH SYNTHESIS
Authors: TAN GUODONG , LI JINLIN , LIEW KONGYONG
Published: March 2012

A series of Ce -incorporated structure of cubic large mesoporous molecular sieves, KIT-6, with different Ce contents were synthesized by a direct hydrothermal process. A sample of Ce -loaded KIT-6 material was synthesised by incipent wetness impregnation. Similarly, catalysts with 15 wt.% Co loading on the above supports were also synthesized by incipient wetness impregnation. The supports and catalysts were characterized by X-ray diffraction, diffuse reflectance UV-vis, solid-state 29Si magic-angle spinning nuclear magnetic resonance, H2 -temperature programmed reduction, H2 -temperature programmed desorption and oxygen titration. The structure of the KIT-6 support was well retained after Ce incorporation. Small amounts of Ce in the Co catalyst were found to improve the activity and increase the selectivity to C5+ hydrocarbons for Fischer–Tropsch synthesis, while larger amounts of Ce had the reverse effect. Meanwhile, methane selectivity shows an opposite trend as compared with that of C5+ selectivity. Ce -loaded KIT-6 supported Co catalyst showed lower activity than KIT-6 supported Co catalyst.
LiFe1-xMnxPO4/C COMPOSITE AS CATHODE MATERIAL FOR LITHIUM ION BATTERY
Authors: LIU AI FANG , WEN ZU BIAO , LIU YA FEI , HU ZHONG HUA
Published: March 2012

LiFe 1-x Mn x PO 4/ C composites were prepared as cathode material for lithium ion battery via solid-state reaction and using glucose as reducing agent and carbon source. The crystal structure and morphology were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The resultant samples were pure olivine compounds with an orthorhombic structure. Their electrochemical performance was studied by galvanostatic charge–discharge test and cyclic voltammetry. The results showed that the sample LiFe0.8Mn0.2PO4/C with an average particle size of 400 nm exhibited the largest discharge capacity of 150 mAh g-1, excellent reversibility of charge–discharge and high capacity retention of 97% after a 50-cycle CV scanning. The improved electrical conductivity corresponding to the fine carbon layer around the LiFe0.8Mn0.2PO4 individual particle can be responsible for all these excellent electrochemical performance.
EXCELLENT CYCLING PERFORMANCE OF THREE-DIMENSIONAL-ORDERED MACROPOROUS NiFe2O4 AS ANODE MATERIAL FOR LITHIUM ION BATTERIES
Authors: ZHANG TIANJING , CAO HUJUN , PENG JUANJUAN , XIAO QIZHEN , LI ZHAOHUI , LEI GANGTIE
Published: March 2012

Three-dimensional ordered macroporous (3DOM) nickel ferrite ( NiFe2O4 ) anode material is synthesized via colloidal crystal template. A Close-packed poly(methyl methacrylate) (PMMA) spheres is used as template. Scanning electron microscopy observations reveal that the obtained 3DOM NiFe2O4 material has uniform spherical macropores with diameter about 140-nm and 20-nm size walls. The cyclic voltammogram and galvanostatic test are employed to evaluate the electrochemical characteristics of the as-prepared NiFe2O4 . It shows high initial discharge capacity (up to 1370 mAh g-1) and reversible capacity of 670 mAh g-1 at the current density of 0.2 mA cm-2. The results suggest that 3DOM nickel ferrite is a good candidate for anode material of lithium ion batteries.
THE STUDY ON SYNTHESIS AND MODIFICATION FOR IRON PHOSPHATE
Authors: YANG X. , ZHANG S. M. , ZHANG J. X. , XU M. Y. , REN P. , LI X. C. , YAN L. C.
Published: March 2012

In order to improve the electrochemical performance of FePO 4, the method of Cr 3+ ion-doped FePO 4 was proposed in this paper. FePO 4 and doped Fe 1-x Cr x PO 4 (x = 0.02,0.04,0.06 and 0.08) were prepared by homogeneous co-precipitation followed by spray drying method, and then the samples were sintered at different temperatures (380°C, 460°C, 550°C and 650°C). Physical-chemical properties were characterized by using thermogravimetric analysis (TG), X-ray diffraction (XRD) and scanning electron microscope (SEM); electrochemical behavior of the samples were analyzed using charge–discharge test, electrochemical impedance spectroscopy (EIS). The results indicated that the Cr 3+ doping can effectively improve the electrochemical performance of FePO 4. Fe 0.96 Cr 0.04 PO 4 sintered at 460°C showed the highest specific capacity of 109.7 mAh/g for the 1st cycle at 0.05 C. In addition, the doping mechanism for FePO 4 was discussed in this paper.
FACILE SYNTHESIS OF HUMIC ACID-COATED IRON OXIDE NANOPARTICLES AND THEIR APPLICATIONS IN WASTEWATER TREATMENT
Authors: ZHOU CHUNJIAO , WU ZHEN , ZHANG WENJIE , XIA MINGXIA , DAI GUOZHANG , ZENG GUANGMING , ZOU BINGSUO , ZHANG PANYUE
Published: March 2012

Humic acid (HA)-coated Fe3O4 ( Fe3O4 /HA) superparamagnetic nanoparticles were synthesized by a chemical co-precipitation method with cheap and environmental friendly iron salts and HA. The as-synthesized samples were characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometer (VSM). The Fe3O4 /HA nanoparticles showed faster adsorption rate and higher removal capacity of cationic organic dye Methylene blue (MB) in neutral water. Moreover, the MB desorption could be easily completed. And the reused performance of Fe3O4 /HA nanoparticles was also excellent.
SnO2 NANOCRYSTALLITE: NOVEL SYNTHETIC ROUTE FROM DEEP EUTECTIC SOLVENT AND LITHIUM STORAGE PERFORMANCE
Authors: GU C. D. , MAI Y. J. , ZHOU J. P. , TU J. P.
Published: March 2012

A new synthetic route to ~4 nm grain-sized SnO 2 was proposed which involved a homogeneous precipitation in a deep eutectic solvent (DES) at room temperature. The white SnO 2 precipitate was obtained from SnCl 2 ⋅ 2 H 2 O dissolved DES by injecting slow drop-wise H 4 N 2 ⋅ H 2 O under stirring. The as-prepared nanocrystalline SnO 2 has a Brunauer–Emmett–Teller surface area of 65.12m2/g with an average Barretl–Joyner–Halenda pore diameter of 3.5 nm. As anode for lithium ion batteries, the nanocrystalline SnO 2 electrode delivered an initial charge capacity as high as 1045 mAh/g and its capacity retention is 58% after 30 cycles.
ULTRATHIN Li4Ti5O12 NANOSHEETS AS A HIGH PERFORMANCE ANODE FOR Li-ION BATTERY
Authors: HONG ZHENSHENG , LAN TONGBIN , XIAO FUYU , ZHANG HUIXING , WEI MINGDENG
Published: March 2012

Ultrathin Li 4 Ti 5 O 12 (LTO) nanosheets were successfully synthesized for the first time using the ultrathin titanate nanowires as a precursor. The synthesized Li 4 Ti 5 O 12 nanosheets have a large surface area of 159.2m2g-1 and their thickness was found to be ca. 5–7 nm. These nanosheets were highly crystalline and used as anode materials in rechargeable lithium-ion batteries. A stable capacity of 150 mAhg-1 for LTO nanosheets can be retained after 70 cycles at a current density of 1 Ag-1 in the voltage window of 2.5–1.0 V. It is notable that a large capacity of 267.5 mAhg-1 was obtained at the second discharge and 166 mAhg-1 can be retained after 70 cycles at 1 Ag-1 in the voltage range of 2.5–0.02 V. These results indicate that the anode materials made of spinel LTO nanosheets displayed a large reversible capacity at a high charge/discharge rate.
Shottky Barrier Diodes on AlN Free-Standing Substrates
Authors: Irokawa Yoshihiro , Víllora Encarnación A. García , Shimamura Kiyoshi
Published: March 2012

Lateral Schottky rectifiers were fabricated on bulk single-crystal free-standing AlN substrates. The unintentionally doped substrates display n-type conductivity. The diode shows a low reverse leakage current of ∼0.1 nA at -40 V at room temperature. The ideality factor for forward characteristics is 11.7 at room temperature and shows temperature dependence, suggesting the lateral nonuniformities at the metal/semiconductor interface. The fabricated devices are stably operated even at 573 K, owing to the wide band gap (6.2 eV) of AlN. The reverse leakage current of the device is explained by either a trap-assisted tunneling process or one-dimensional variable-range-hopping conduction along the dislocations.
On-Chip High-Resolution Beam Scanner Based on Bragg Reflector Slow-Light Waveguide Amplifier and Tunable Micro-Electro-Mechanical System Vertical Cavity Surface Emitting Laser
Authors: Nakahama Masanori , Gu Xiaodong , Shimada Toshikazu , Koyama Fumio
Published: March 2012

We propose a monolithic beam scanner consisting of a Bragg reflector slow-light waveguide amplifier and a tunable micro-electro-mechanical vertical cavity surface emitting laser. Continuous beam steering of over 30° and a narrow divergence angle of below 0.1° are predicted, which gives us a number of resolution points over 300. In addition, the modeling on saturation characteristics of a slow light amplifier shows a possibility of the maximum output power of over 10 mW.
A Compact 2 Degree-of-Freedom Energy Harvester with Cut-Out Cantilever Beam
Authors: Wu Hao , Tang Lihua , Yang Yaowen , Soh Chee Kiong
Published: March 2012

In this work, a novel 2 degree-of-freedom (DOF) vibration energy harvester is proposed. The harvester comprises one main cantilever beam and one secondary cantilever beam cut out within the main beam. By varying the proof masses, the first two resonances can be tuned close to each other, while maintaining significant magnitudes, thus providing a useful wide bandwidth for energy harvesting. Unlike previous 2-DOF harvesters, the proposed harvester is compact and utilizes the beam more efficiently by generating energy from both the main and secondary cantilevers. Therefore, the proposed harvester is more adaptive and functional in practical random or frequency-variant vibrational circumstances.
Ta2O5 Polycrystalline Silicon Capacitors with CF4 Plasma Treatment
Authors: Kao Chyuan-Haur , Chen Hsiang
Published: March 2012

In this research, the effects of CF4 plasma treatment with post annealing on the electrical characteristics and material properties of Ta2O5 dielectrics were determined. The dielectric performance characteristics of samples under different treatment conditions were measured using equivalent oxide thickness (EOT), current density–electric field (J–E) characteristics, gate voltage shift versus time, and Weibull plots. In addition, X-ray diffraction (XRD) analysis provided insight into the changes in crystalline structure, atomic force microscopy (AFM) measurements visualized the surface roughness, and secondary ion mass spectroscopy (SIMS) revealed the distribution of fluorine ions inside the dielectric samples. Findings indicate that dielectric performance can be significantly improved by CF4 plasma treatment for 1 min with post annealing at 800 °C. The improvements in electrical characteristics were caused by the appropriate incorporation of the fluorine atoms and the removal of the dangling bonds and traps. The Ta2O5 dielectric incorporated with appropriate CF4 plasma and annealing treatments shows great promise for future generation of nonvolatile memory applications.
Light Trapping by Ag Nanoparticles Chemically Assembled inside Thin-Film Hydrogenated Microcrystalline Si Solar Cells
Authors: Mizuno Hidenori , Sai Hitoshi , Matsubara Koji , Kondo Michio
Published: March 2012

A systematic study on the Ag nanoparticle (NP)-mediated light trapping in thin film hydrogenated microcrystalline Si (µc-Si:H) solar cells is described. In this study, a unique wet-chemical approach was applied to allow the assembly of light scattering Ag NPs inside the rear ZnO:Ga layer of µc-Si:H solar cells in a controlled manner. It was confirmed that both the surface coverage by the Ag NPs and the location of the Ag NPs in the ZnO:Ga layer have significant impacts on the final light trapping effect. By optimizing these two parameters, a 75% higher current density generated in the near-infrared range (700–1100 nm) was achieved in a Ag NP-incorporated cell compared with a cell without the Ag NP incorporation.
Fundamental Properties of Novel Design Microstrip Line Type of Liquid Crystal Phase Shifter in Microwave Region
Authors: Ito Ryouta , Kawakami Takayuki , Ito Yusuke , Sasamori Takayuki , Isota Yoji , Honma Michinori , Nose Toshiaki
Published: March 2012

A planar-type electrically tunable phase shifter is demonstrated in the microwave region by using liquid crystal (LC) materials. A novel planar waveguide structure based on the microstrip line, which can convert the normal microstrip line to the inverted one, is designed. The new conversion circuit enables us to introduce LC materials on the microstrip line as easily as in the case of using the coplanar waveguide type of liquid crystal phase shifters. Larger phase shifting properties are confirmed empirically up to approximately 10 GHz with the application of a driving voltage of less than 10 V.
AC Power Consumption of Single-Walled Carbon Nanotube Interconnects: Non-Equilibrium Green's Function Simulation
Authors: Yamamoto Takahiro , Sasaoka Kenji , Watanabe Satoshi
Published: March 2012

We theoretically investigate the emittance and dynamic dissipation of a nanoscale interconnect consisting of a metallic single-walled carbon nanotube using the non-equilibrium Green's function technique for AC electronic transport. We show that the emittance and dynamic dissipation depend strongly on the contact conditions of the interconnect and that the power consumption can be reduced by adjusting the contact conditions. We propose an appropriate condition of contact that yields a high power factor and low apparent power.
Theoretical Investigation of Chemical Spin Doping into Single Porphyrin Junctions toward Ultrahigh-Sensitive Nitric Oxide Sensor
Authors: Toyoda Kenji
Published: March 2012

We theoretically study chemical spin doping into single porphyrins connected to nanoelectrodes via benzenethiols, ethynyl-benzenethiols, and vinyl-benzenethiols using the adsorption of a nitric oxide (NO) molecule. For all three anchoring groups, the adsorption of a NO molecule injects one spin into single-molecule junctions and produces antiferromagnetic interactions between the injected spin and the original spins at the junctions, resulting in a decrease in the spin-polarized currents. We found that the magnitude of change in the spin-polarized current significantly depends on the type of anchoring groups; the magnitude is ordered by the following anchoring group: vinyl-benzenethiol > ethynyl-benzenethiol > benzenethiol. In particular, for vinyl-benzenethiol, spin doping causes not only π electron localization on molecular orbitals but also structural change.
Fabrication and Electrical Properties of Thermally Oxidized p-Channel Metal–Oxide–Semiconductor Field-Effect Transistors on 4H-SiC C-Face
Authors: Okamoto Mitsuo , Iijima Miwako , Fukuda Kenji , Okumura Hajime
Published: March 2012

We characterized the SiO2/SiC interface by capacitance–voltage (C–V) measurement in order to obtain p-channel metal–oxide–semiconductor field-effect transistors (MOSFETs) on the 4H-SiC(0001̄) C-face. Wet gate oxidation was preferable for both n- and p-type MOS capacitors, but p-type MOS interface properties were inferior to those of n-type MOS capacitors. The cause of the large flat-band shift for the p-type sample was discussed on the basis of C–V measurements by the light illumination technique. We also investigated the influence of the high-temperature annealing process after gate oxidation on the MOS interface properties. The p-type MOS interface was more sensitive to the annealing process than the n-type MOS interface. We fabricated 4H-SiC C-face p-channel MOSFETs by wet gate oxidation and low-temperature postdeposition annealing in He–H2 ambient. The normal FET operation was accomplished on the 4H-SiC C-face for the first time. Those devices, however, indicated low channel mobility and large threshold voltage.
Deciphering the mechanisms of the Na+/H+ exchanger-3 regulation in organ dysfunction
Authors: Girardi Adriana C. C. , Di Sole Francesca
Published: March 2012

The Na+/H+ exchanger-3 (NHE3) belongs to the mammalian NHE protein family and catalyzes the electro-neutral exchange of extracellular sodium for intracellular proton across cellular membranes. Its transport function is of essential importance for the maintenance of the body's salt and water homeostasis as well as acid-base balance. Indeed, NHE3 activity is finely regulated by a variety of stimuli, both acutely and chronically, and its transport function is fundamental for a multiplicity of severe and world-wide infection-pathological conditions. This review aims to provide a concise overview of NHE3 physiology and discusses the role of NHE3 in clinical conditions of prominent importance, specifically in hypertension, diabetic nephropathy, heart failure, acute kidney injury, and diarrhea. Study of NHE3 function in models of these diseases has contributed to the deciphering of mechanisms that control the delicate ion balance disrupted in these disorders. The majority of the findings indicate that NHE3 transport function is activated before the onset of hypertension and inhibited thereafter; NHE3 transport function is also upregulated in diabetic nephropathy and heart failure, while it is reported to be downregulated in acute kidney injury and in diarrhea. The molecular mechanisms activated during these pathological conditions to regulate NHE3 transport function are examined with the aim of linking NHE3 dysfunction to the analyzed clinical disorders.
Sensitivity of TRPM7 channels to Mg2+ characterized in cell-free patches of Jurkat T lymphocytes
Authors: Chokshi Rikki , Matsushita Masayuki , Kozak J. Ashot
Published: March 2012

Transient receptor potential melastatin 7 (TRPM7) channels were originally identified electrophysiologically when depletion of cytosolic Mg2+ resulted in the gradual development of an outwardly rectifying cation current. Conversely, inclusion of millimolar Mg2+ in internal solutions prevented activation of these channels in whole cell patch clamp. We recently demonstrated that the Jurkat T-cell whole cell TRPM7 channels are inhibited by internal Mg2+ in a biphasic manner, displaying high [IC50(1) ≈ 10 μM] and low [IC50(2) ≈ 165 μM] affinity inhibitor sites. In that study, we had characterized the dependence of the maximum cell current density on intracellular Mg2+ concentration. To characterize Mg2+ inhibition in Jurkat T cells in more detail and compare it to whole cell results, we recorded single TRPM7 channels in cell-free membrane patches and investigated the dependence of their activity on Mg2+ added on the cytoplasmic side. We systematically varied free Mg2+ from 265 nM to 407 μM and evaluated the extent of channel inhibition in inside-out patch for 58 patches. We found that the TRPM7 channel shows two conductance levels of 39.0 pS (γ1) and 18.6 pS (γ2) and that both are reversibly inhibited by internal Mg2+. The 39.0-pS conductance is the dominant state of the channel, observed most frequently in this recording configuration. The dose-response relation in inside-out patches shows a steeper Mg2+ dependence than in whole cell, yielding IC50(1) of 25.1 μM and IC50(2) of 91.2 μM.. Single-channel analysis shows that the primary effect of Mg2+ in multichannel patches is a reversible reduction of the number of conducting channels (No). Additionally, at high Mg2+ concentrations, we observed a saturating 20% reduction in unitary conductance (γ1). Thus Mg2+ inhibition in whole cell can be explained by a drop in individual participating channels and a modest reduction in conductance. We also found that TRPM7 channels in some patches were not sensitive to this ion at submaximal Mg2+ concentrations. Interestingly, Mg2+ inhibition showed the property of use dependence: with repeated applications, Mg2+ effect became gradually more potent, which suggests that Mg2+ sensitivity of the channel is a dynamic characteristic that depends on other membrane factors.
An osteoclastic protein-tyrosine phosphatase regulates the β3-integrin, syk, and shp1 signaling through respective src-dependent phosphorylation in osteoclasts
Authors: William Lau K.-H. , Stiffel Virginia , Amoui Mehran
Published: March 2012

This study utilized the glutathione transferase (GST) pull-down assay to identify novel substrates of an osteoclastic protein-tyrosine phosphatase, PTP-oc. Consistent with the previous findings that the phosphorylated tyr-527 (pY527) of Src is a substrate of PTP-oc, the major protein pulled down with the phosphatase-deficient (PD)-PTP-oc-GST trapping mutant in RAW264.7 cells was Src. The GST-PD-PTP-oc also pulled down pY-Syk and pY-β3-integrin, but not after PP2 pretreatment. However, PTP-oc transgenic osteoclasts or PTP-oc-overexpressing RAW264.7 cells had elevated, and not reduced, levels of pY525/526-Syk and pY759-β3 integrin, and the PTP-oc siRNA treatment drastically reduced levels of pY525/526 Syk and pY759-β3-integrin in RAW264.7 cells. These findings are incompatible with the premise that they are substrates of PTP-oc. The PTP-oc-dependent increases in pY525/526-Syk and pY759-β3-integrin levels were completely blocked by PP2, indicating that these effects are secondary to PTP-oc-mediated activation of the Src protein-tyrosine kinase (PTK). Overexpression of PTP-oc increased, and siRNA-mediated suppression of PTP-oc reduced, pY160-Vav1, pY173-Vav3, and pY783-PLCγ levels, and Rac1 activation, which are downstream mediators of the ITAM/Syk signaling. Overexpression of PTP-oc also increased, and PTP-oc siRNA treatment decreased, the pY-Shp1 levels, which were blocked by PP2. Since Shp1 is a negative regulator of osteoclast activity and is a key mediator of the ITIM signaling, these findings suggest that PTP-oc is an upstream suppressor of the ITIM/Shp1 signaling through PTP-oc-induced Src-dependent Shp1 phosphorylation. In summary, PTP-oc plays a central regulatory role in the concerted regulation of the β3-integrin, the ITAM/Syk, and the ITIM/Shp1 signaling indirectly through activation of Src PTK.
New insights into the dynamic regulation of water and acid-base balance by renal epithelial cells
Authors: Brown Dennis , Bouley Richard , Pǎunescu Teodor G. , Breton Sylvie , Lu Hua A. J.
Published: March 2012

Maintaining tight control over body fluid and acid-base homeostasis is essential for human health and is a major function of the kidney. The collecting duct is a mosaic of two cell populations that are highly specialized to perform these two distinct processes. The antidiuretic hormone vasopressin (VP) and its receptor, the V2R, play a central role in regulating the urinary concentrating mechanism by stimulating accumulation of the aquaporin 2 (AQP2) water channel in the apical membrane of collecting duct principal cells. This increases epithelial water permeability and allows osmotic water reabsorption to occur. An understanding of the basic cell biology/physiology of AQP2 regulation and trafficking has informed the development of new potential treatments for diseases such as nephrogenic diabetes insipidus, in which the VP/V2R/AQP2 signaling axis is defective. Tubule acidification due to the activation of intercalated cells is also critical to organ function, and defects lead to several pathological conditions in humans. Therefore, it is important to understand how these “professional” proton-secreting cells respond to environmental and cellular cues. Using epididymal proton-secreting cells as a model system, we identified the soluble adenylate cyclase (sAC) as a sensor that detects luminal bicarbonate and activates the vacuolar proton-pumping ATPase (V-ATPase) via cAMP to regulate tubular pH. Renal intercalated cells also express sAC and respond to cAMP by increasing proton secretion, supporting the hypothesis that sAC could function as a luminal sensor in renal tubules to regulate acid-base balance. This review summarizes recent advances in our understanding of these fundamental processes.
Chemokine-like receptor 1 regulates skeletal muscle cell myogenesis
Authors: Issa Mark E. , Muruganandan Shanmugam , Ernst Matthew C. , Parlee Sebastian D. , Zabel Brian A. , Butcher Eugene C. , Sinal Christopher J. , Goralski Kerry B.
Published: March 2012

The chemokine-like receptor-1 (CMKLR1) is a G protein-coupled receptor that is activated by chemerin, a secreted plasma leukocyte attractant and adipokine. Previous studies identified that CMKLR1 is expressed in skeletal muscle in a stage-specific fashion during embryogenesis and in adult mice; however, its function in skeletal muscle remains unclear. Based on the established function of CMKLR1 in cell migration and differentiation, we investigated the hypothesis that CMKLR1 regulates the differentiation of myoblasts into myotubes. In C2C12 mouse myoblasts, CMKLR1 expression increased threefold with differentiation into multinucleated myotubes. Decreasing CMKLR1 expression by adenoviral-delivered small-hairpin RNA (shRNA) impaired the differentiation of C2C12 myoblasts into mature myotubes and reduced the mRNA expression of myogenic regulatory factors myogenin and MyoD while increasing Myf5 and Mrf4. At embryonic day 12.5 (E12.5), CMKLR1 knockout (CMKLR1−/−) mice appeared developmentally delayed and displayed significantly lower wet weights and a considerably diminished myotomal component of somites as revealed by immunolocalization of myosin heavy chain protein compared with wild-type (CMKLR1+/+) mouse embryos. These changes were associated with increased Myf5 and decreased MyoD protein expression in the somites of E12.5 CMKLR1−/− mouse embryos. Adult male CMKLR1−/− mice had significantly reduced bone-free lean mass and weighed less than the CMKLR1+/+ mice. We conclude that CMKLR1 is essential for myogenic differentiation of C2C12 cells in vitro, and the CMKLR1 null mice have a subtle skeletal muscle deficit beginning from embryonic life that persists during postnatal life.
Using lithium to probe sequential cation interactions with GAT1
Authors: Meinild Anne-Kristine , Forster Ian C.
Published: March 2012

Li+ interacts with the Na+/Cl−-dependent GABA transporter, GAT1, under two conditions: in the absence of Na+ it induces a voltage-dependent leak current; in the presence of Na+ and GABA, Li+ stimulates GABA-induced steady-state currents. The amino acids directly involved in the interaction with the Na+ and Li+ ions at the so-called “ Na2” binding site have been identified, but how Li+ affects the kinetics of GABA cotransport has not been fully explored. We expressed GAT1 in Xenopus oocytes and applied the two-electrode voltage clamp and 22Na uptake assays to determine coupling ratios and steady-state and presteady-state kinetics under experimental conditions in which extracellular Na+ was partially substituted by Li+. Three novel findings are: 1) Li+ reduced the coupling ratio between Na+ and net charge translocated during GABA cotransport; 2) Li+ increased the apparent Na+ affinity without changing its voltage dependence; 3) Li+ altered the voltage dependence of presteady-state relaxations in the absence of GABA. We propose an ordered binding scheme for cotransport in which either a Na+ or Li+ ion can bind at the putative first cation binding site ( Na2). This is followed by the cooperative binding of the second Na+ ion at the second cation binding site ( Na1) and then binding of GABA. With Li+ bound to Na2, the second Na+ ion binds more readily GAT1, and despite a lower apparent GABA affinity, the translocation rate of the fully loaded carrier is not reduced. Numerical simulations using a nonrapid equilibrium model fully recapitulated our experimental findings.
Systems genetic analysis of multivariate response to iron deficiency in mice
Authors: Yin Lina , Unger Erica L. , Jellen Leslie C. , Earley Christopher J. , Allen Richard P. , Tomaszewicz Ann , Fleet James C. , Jones Byron C.
Published: March 2012

The aim of this study was to identify genes that influence iron regulation under varying dietary iron availability. Male and female mice from 20+ BXD recombinant inbred strains were fed iron-poor or iron-adequate diets from weaning until 4 mo of age. At death, the spleen, liver, and blood were harvested for the measurement of hemoglobin, hematocrit, total iron binding capacity, transferrin saturation, and liver, spleen and plasma iron concentration. For each measure and diet, we found large, strain-related variability. A principal-components analysis (PCA) was performed on the strain means for the seven parameters under each dietary condition for each sex, followed by quantitative trait loci (QTL) analysis on the factors. Compared with the iron-adequate diet, iron deficiency altered the factor structure of the principal components. QTL analysis, combined with PosMed (a candidate gene searching system) published gene expression data and literature citations, identified seven candidate genes, Ptprd, Mdm1, Picalm, lip1, Tcerg1, Skp2, and Frzb based on PCA factor, diet, and sex. Expression of each of these is cis-regulated, significantly correlated with the corresponding PCA factor, and previously reported to regulate iron, directly or indirectly. We propose that polymorphisms in multiple genes underlie individual differences in iron regulation, especially in response to dietary iron challenge. This research shows that iron management is a highly complex trait, influenced by multiple genes. Systems genetics analysis of iron homeostasis holds promise for developing new methods for prevention and treatment of iron deficiency anemia and related diseases.
Tumor necrosis factor-α receptor type 1, not type 2, mediates its acute responses in the kidney
Authors: Castillo Alexander , Islam M. Toriqul , Prieto Minolfa C. , Majid Dewan S. A.
Published: March 2012

Acute administration of tumor necrosis factor-α (TNF-α) resulted in decreases in renal blood flow (RBF) and glomerular filtration rate (GFR) but induced diuretic and natriuretic responses in mice. To define the receptor subtypes involved in these renal responses, experiments were conducted to assess the responses to human recombinant TNF-α (0.3 ng·min−1·g body wt−1iv infusion for 75 min) in gene knockout (KO) mice for TNF-α receptor type 1 (TNFαR1 KO, n = 5) or type 2 (TNFαR2 KO, n = 6), and the results were compared with those obtained in corresponding wild-type [WT (C57BL/6), n = 6] mice. Basal levels of RBF (PAH clearance) and GFR (inulin clearance) were similar in TNFαR1 KO, but were lower in TNFαR2 KO, than WT mice. TNF-α infusion in WT mice decreased RBF and GFR but caused a natriuretic response, as reported previously. In TNFαR1 KO mice, TNF-α infusion failed to cause such vasoconstrictor or natriuretic responses; rather, there was an increase in RBF and a decrease in renal vascular resistance. Similar responses were also observed with infusion of murine recombinant TNF-α in TNFαR1 KO mice ( n = 5). However, TNF-α infusion in TNFαR2 KO mice caused changes in renal parameters qualitatively similar to those observed in WT mice. Immunohistochemical analysis in kidney slices from WT mice demonstrated that while both receptor types were generally located in the renal vascular and tubular cells, only TNFαR1 was located in vascular smooth muscle cells. There was an increase in TNFαR1 immunoreactivity in TNFαR2 KO mice, and vice versa, compared with WT mice. Collectively, these functional and immunohistological findings in the present study demonstrate that the activation of TNFαR1, not TNFαR2, is mainly involved in mediating the acute renal vasoconstrictor and natriuretic actions of TNF-α.
Protein abundance of urea transporters and aquaporin 2 change differently in nephrotic pair-fed vs. non-pair-fed rats
Authors: Bou Matar Raed N. , Malik Bela , Wang Xiaonan H. , Martin Christopher F. , Eaton Douglas C. , Sands Jeff M. , Klein Janet D.
Published: March 2012

Salt and water retention is a hallmark of nephrotic syndrome (NS). In this study, we test for changes in the abundance of urea transporters, aquaporin 2 (AQP2), Na-K-2Cl cotransporter 2 (NKCC2), and Na-Cl cotransporter (NCC), in non-pair-fed and pair-fed nephrotic animals. Doxorubicin-injected male Sprague-Dawley rats ( n = 10) were followed in metabolism cages. Urinary excretion of protein, sodium, and urea was measured periodically. Kidney inner medulla (IM), outer medulla, and cortex tissue samples were dissected and analyzed for mRNA and protein abundances. At 3 wk, all doxorubicin-treated rats developed features of NS, with a ninefold increase in urine protein excretion (from 144 ± 21 to 1,107 ± 165 mg/day; P < 0.001) and reduced urinary sodium excretion (from 0.17 to 0.12 meq/day; P < 0.001). Urine osmolalities were reduced in the nephrotic animals (1,057 ± 37, treatment vs. 1,754 ± 131, control). Unlike animals fed ad libitum, UT-A1 protein abundance was unchanged in nephrotic pair-fed rats. Glycosylated AQP2 was reduced in the IM base of both nephrotic groups. Abundances of NKCC2 and NCC were consistently reduced (71 ± 7 and 33 ± 13%, respectively) in both nephrotic pair-fed animals and animals fed ad libitum. In pair-fed nephrotic rats, we observed an increase in the cleaved form of membrane-bound γ-epithelial sodium channel (ENaC). However, α- and β-ENaC subunits were unaltered. NKCC2 and AQP2 mRNA levels were similar in treated vs. control rats. We conclude that dietary protein intake affects the response of medullary transport proteins to NS.
Rat airway morphometry measured from in situ MRI-based geometric models
Authors: Oakes Jessica M. , Scadeng Miriam , Breen Ellen C. , Marsden Alison L. , Darquenne Chantal
Published: March 2012

Rodents have been widely used to study the environmental or therapeutic impact of inhaled particles. Knowledge of airway morphometry is essential in assessing geometric influence on aerosol deposition and in developing accurate lung models of aerosol transport. Previous morphometric studies of the rat lung performed ex situ provided high-resolution measurements (50–125 μm). However, it is unclear how the overall geometry of these casts might have differed from the natural in situ appearance. In this study, four male Wistar rat (268 ± 14 g) lungs were filled sequentially with perfluorocarbon and phosphate-buffered saline before being imaged in situ in a 7-T magnetic resonance (MR) scanner at a resolution of 0.2 × 0.2 × 0.27 mm. Airway length, diameter, gravitational, bifurcation, and rotational angles were measured for the first four airway generations from 3D geometric models built from the MR images. Minor interanimal variability [expressed by the relative standard deviation RSD (=SD/mean)] was found for length (0.18 ± 0.07), diameter (0.15 ± 0.15), and gravitational angle (0.12 ± 0.06). One rat model was extended to 16 airway generations. Organization of the airways using a diameter-defined Strahler ordering method resulted in lower interorder variability than conventional generation-based grouping for both diameter (RSD = 0.12 vs. 0.42) and length (0.16 vs. 0.67). Gravitational and rotational angles averaged 82.9 ± 37.9° and 53.6 ± 24.1°, respectively. Finally, the major daughter branch bifurcated at a smaller angle (19.3 ± 14.6°) than the minor branch (60.5 ± 19.4°). These data represent the most comprehensive set of rodent in situ measurements to date and can be used readily in computational studies of lung function and aerosol exposure.