bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonutility of routine testing of stool for ova and parasites in a tertiary care Canadian centre
Authors: Mosli Mahmoud , Gregor Jamie , Chande Nilesh , Lannigan Robert
Published: May 2012

Background In many clinical situations, stool examinations for ova and parasites (O&P) are routine in the work-up of patients with acute or chronic diarrhea. Frequently, these tests are found to be negative for pathogens. The purpose of this study was to examine the diagnostic yield of routine stool testing for O&P in a Canadian tertiary care centre and to estimate the potential clinical benefit of a positive result. Patients and Methods All stool samples sent to the central microbiology laboratory at London Health Sciences Centre were reviewed over a 5-year period ending January 2010. Initial screening was done by direct antigen testing using an enzyme immunoassay (EIA) technique followed by direct microscopy for negative results where there was a high index of suspicion and for positive results to rule out any concurrent parasites not included in the EIA kit. Pathogens identified were categorized and their potential susceptibility to metronidazole was estimated. No clinical data were available, as this was purely a utilization study. Results A total of 5812 stool tests were ordered. Of these, 5681 (97.7%) were completed. The most common reasons for an incomplete test were sample leakage (n = 38) and use of the incorrect collection kit (n = 32). Direct microscopy identified white blood cells in 17% of patients with positive testing. The most common pathogen was Giardia lamblia , which was detected in 45/83 (54%) of positive specimens. Entamoeba histolytica / Entamoeba dispar was identified in 16/83 (19%) and Cryptosporidium spp. in 10/83 (12%) of positive specimens. Microorganisms not thought to be pathogenic were identified in 7/83 (8%). Direct laboratory costs independent of labor were estimated at $1836 per clinically significant organism identified. Of the 77 specimens positive for pathogenic organisms, 62 (81%) were likely to be sensitive to treatment with metronidazole. Conclusion In a tertiary care centre, the diagnostic yield of routine testing of stool for O&P during the evaluation of patients with acute or chronic diarrhea is low. Most clinically significant positive results should be responsive to metronidazole, but empirical treatment is not encouraged. Strategies to identify patients with a higher likelihood of harboring pathogenic parasites and consideration of empiric metronidazole therapy for patients at highest risk merit further research.
Protective immune responses in mice induced by intramuscular and intranasal immunization with aMycoplasma pneumoniaeP1C DNA vaccine
Authors: Zhu Cuiming , Wu Yimou , Chen Sufang , Yu Minjun , Zeng Yanhua , You Xiaoxing , Xiao Jinhong , Wang Shiping
Published: May 2012

Mycoplasma pneumoniae is an important causative agent of atypical pneumonia. This study was to determine the ability of a DNA expression vector, which encodes the carboxy terminal region of the M. pneumoniae P1 protein (P1C), to induce humoral and cellular immune responses and to protect against M. pneumoniae infection in BALB/c mice. Mice were immunized with pcDNA3.1/P1C by either intramuscular injection (i.m.) or intranasal inoculation (i.n.). Our results showed that p1c DNA immunization generates detectable antibodies specific to M. pneumoniae, and elicits high levels of IgG1, IgG2a, and IgG2b isotypes (P < 0.01). The levels of IFN-γ and IL-4 in spleen cells of the immunized mice were significantly elevated by immunization via both the i.m. and i.n. methods. Moreover, p1c DNA-immunized mice exhibited detectable protection against M. pneumoniae infection. The lung tissue inflammation was relieved and the histopathologic score (HPS) of pcDNA3.1/P1C-immunized mice was significantly decreased than those in phosphate-buffed saline (PBS) or vaccine-vector-immunized mice (P < 0.01), whereas there were no significant differences in HPS between i.m. and i.n. vaccination (P > 0.05). Our results suggest that pcDNA3.1/P1C could be useful for developing a vaccine against M. pneumoniae infection.
PRINCIPLES OF SINGLE-MOLECULE MANIPULATION AND ITS APPLICATION IN BIOLOGICAL PHYSICS
Authors: CHEN WEI-HUNG , WILSON JONATHAN D. , WIJERATNE SITHARA S. , SOUTHMAYD SARAH A. , LIN KUAN-JIUH , KIANG CHING-HWA
Published: May 2012

Recent advances in nanoscale manipulation and piconewton force detection provide a unique tool for studying the mechanical and thermodynamic properties of biological molecules and complexes at the single-molecule level. Detailed equilibrium and dynamics information on proteins and DNA have been revealed by single-molecule manipulation and force detection techniques. The atomic force microscope (AFM) and optical tweezers have been widely used to quantify the intra- and inter-molecular interactions of many complex biomolecular systems. In this article, we describe the background, analysis, and applications of these novel techniques. Experimental procedures that can serve as a guide for setting up a single-molecule manipulation system using the AFM are also presented.
MODELING AND PREDICTING THE ELECTRICAL CONDUCTIVITY OF COMPOSITE CATHODE FOR SOLID OXIDE FUEL CELL BY USING SUPPORT VECTOR REGRESSION
Authors: TANG J. L. , CAI C. Z. , XIAO T. T. , HUANG S. J.
Published: May 2012

The electrical conductivity of solid oxide fuel cell (SOFC) cathode is one of the most important indices affecting the efficiency of SOFC. In order to improve the performance of fuel cell system, it is advantageous to have accurate model with which one can predict the electrical conductivity. In this paper, a model utilizing support vector regression (SVR) approach combined with particle swarm optimization (PSO) algorithm for its parameter optimization was established to modeling and predicting the electrical conductivity of Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ-x Sm 0.5 Sr 0.5 CoO 3-δ (BSCF–xSSC) composite cathode under two influence factors, including operating temperature (T) and SSC content (x) in BSCF–xSSC composite cathode. The leave-one-out cross validation (LOOCV) test result by SVR strongly supports that the generalization ability of SVR model is high enough. The absolute percentage error (APE) of 27 samples does not exceed 0.05%. The mean absolute percentage error (MAPE) of all 30 samples is only 0.09% and the correlation coefficient (R2) as high as 0.999. This investigation suggests that the hybrid PSO–SVR approach may be not only a promising and practical methodology to simulate the properties of fuel cell system, but also a powerful tool to be used for optimal designing or controlling the operating process of a SOFC system.
Dilithium phthalocyanine as a catalyst for oxygen reduction in non-aqueousLi-O2cells
Authors: Selvaraj C. , Munichandraiah N. , Scanlon L.G.
Published: May 2012

The electrochemical performance of Li-O2cells depends mainly on the kinetics of the cathode reaction, namely, oxygen reduction reaction in non-aqueous electrolytes. The catalyst plays an important role on the kinetics of the reaction. In the present work, dilithium phthalocyanine is used as the catalyst in the cathode of Li-O2cells. Dual-layer O2electrodes are fabricated employing a high surface area microporous carbon with Ni gauge current collector present between the two layers. Discharge capacity of Li-O2cell measured at 0.2 mA.cm-2is about 30 mAh.cm-2. Phthalocyanine ring is considered to interact with O2producing Li2Pc+δ- O2-δas a reaction intermediate, which facilitates the electron-transfer reaction.
Crystal structure of a chiral binaphthyl porphyrin
Authors: Rose Eric , Raoul Nicolas , Ethève-Quelquejeu Mélanie , Gallo Emma , Boitrel Bernard , Pécaut Jacques , Dubois Lionel
Published: May 2012

Condensation of tetrakis-5,10,15,20-(α,β,α,β-2-aminophenyl)porphyrin atropoisomer with 1,1′-binaphthyl, 2,2′-dimethoxy-3,3′-diacetylchloride afforded the corresponding basket handle porphyrin whose structure has been analyzed by X-ray crystallography. The macrocycle presents a ruffled type plane according to Shelnutt method for classifying and quantifying the out-of-plane and in-plane distortion of a porphyrin. This structure clearly shows the position of the methoxy groups with respect to the center of the porphyrin and their possible role in the enantioselective epoxidation and cyclopropanation of olefins.
The overhanging carboxylic acid strategy: an alternative route to the porphyrin core expansion/modification for the coordination of large metal ions
Authors: Le Gac Stéphane , Boitrel Bernard
Published: May 2012

This account summarizes how the binding properties of a regular porphyrin macrocycle for large cations can be significantly modified and even tuned when the surrounding skeleton delivers at least one carboxylic acid group close to the N -core. While kinetics of metal insertion are drastically improved, unique dinuclear species can be obtained with a possible control of the nuclearity. The first incorporation of an α-core emitter radioisotope of particular interest for cancer therapy was recently demonstrated. All in all, this overhanging carboxylic acid strategy can be regarded as an alternative to either expanded porphyrins for the coordination of large cations from groups 14–15 (PbII, BiIII) or contracted and isomeric porphyrins for the coordination of smaller cations from group 12 (HgII)
10 Gbps Colorless Optical Source in Wavelength-Division Multiplexed Passive Optical Networks for Monolithic Integration of Deep-Ridge Waveguide Electroabsorption Modulator with Planar Buried-Heterostructure Semiconductor Optical Amplifier
Authors: Kim Dong Churl , Kim Ki Soo , Kim Hyun-Soo , Choi Byung-Seok , Kwon O-Kyun
Published: May 2012

For the 10 Gbps colorless optical source in wavelength-division multiplexed passive optical networks (WDM-PONs), we have fabricated a semiconductor optical amplifier-reflective electorabsorption modulator (SOA-REAM) by monolithic integration of deep-ridge waveguide REAM (DRW-REAM) with planar buried-heterostructure (PBH) SOA using a PNP-current blocking layer. The SOA-REAM has a spot-size convertor for easy fiber coupling. Using a butterfly module with an SMA connector, we have packaged the SOA-REAM. At a -10 dBm input power of 1550 nm, the saturation output power is about 6 dBm. At 10.7 Gbps, we can obtain clear eye diagrams, and the power penalty at 10-9 bit-error rate (BER) after 20 km transmission is less than 1 dB over 35 nm.
Crack-Free AlN/GaN Distributed Bragg Reflectors on AlN Templates
Authors: Yagi Kouta , Kaga Mitsuru , Yamashita Kouji , Takeda Kenichirou , Iwaya Motoaki , Takeuchi Tetsuya , Kamiyama Satoshi , Amano Hiroshi , Akasaki Isamu
Published: May 2012

We have demonstrated crack-free 30-pair-AlN/GaN distributed Bragg reflectors (DBRs) grown on AlN templates for the first time. A reasonably high reflectivity of 97.5% was obtained. X-ray diffraction measurements revealed that the AlN templates cause compressive stress in DBRs. At the same time, the AlN/GaN DBRs were found to relax to average AlGaN alloys with AlN mole fractions determined by the thickness ratio of the AlN layer to one pair of AlN and GaN in DBRs regardless of the underlying template, AlN or GaN.
Shape Control of Trenched 4H-SiC C-Face by Thermal Chlorine Etching
Authors: Koketsu Hidenori , Hatayama Tomoaki , Yano Hiroshi , Fuyuki Takashi
Published: May 2012

The shape control inside a trenched 4H-SiC by atmospheric-pressure chlorine (Cl2) etching has been investigated. The trench fabricated by a plasma process on the 4H-SiC(0001̄) C-face with 4°-off toward [112̄0] was used. The inside of the 4H-SiC trench was thermally etched in Cl2 ambience at 900 °C. The subtrenches intentionally formed by the plasma process were successfully eliminated along with thermal Cl2 etching. With further Cl2 etching, the 4°-off (0001̄) C-face at the trench bottom disappeared and the V-shaped bottom with a specific angle for the (0001̄) basal plane was formed. The mechanism underlying the change inside the trench shape is discussed in comparison with the off-angle dependence of Cl2 etching rate.
Simulation of Material Properties of Barium Titanate Single Crystal with Multidomain Structure Using Modified Time-Dependent Devonshire–Ginzburg–Landau Model
Authors: Imanaga Syunji , Miura Kaoru
Published: May 2012

We simulated and compared the material properties of the tetragonal phase of barium titanate for two types of multidomain structures, namely, multidomain-1 including both 90 and 180° domains, and multidomain-2 including only the 180° domain, and a monodomain by using a modified time-dependent Devonshire–Ginzburg–Landau model of two dimensions. We found that the piezoelectric coefficient d
12 and dielectric susceptibility η22 of muiltidomain-1 are about 6.5 times larger than those of the monodomain, and the large values of d
12 and η22 of multidomain-1 are explained by considering its peculiar multidomain structure. Moreover, we found that the piezoelectric coefficient d
22 of muiltidomain-2 before polling is about one-half that of the monodomain, and that of muiltidomain-2 after polling is about two times larger than that before polling, whereas the value of η22 before polling is three times larger than that after polling.
Uniform Dispersion of Liquid Crystal Droplets in the Polymer Matrix by Chemical Affinity Difference-Induced Phase Separation
Authors: Shen Zheng-Guo , Lee Ji-Hoon , Yoon Tae-Hoon
Published: May 2012

We proposed a method to obtain uniformly dispersed liquid crystal (LC) droplets in the polymer matrix. Polymer spacers were formed on the bottom substrate and the LC–reactive monomer (RM) mixture was injected between the substrates in the isotropic phase. After cooling to the room temperature, the RM molecules which have higher chemical affinity to the polymer spacers were diffused to the polymer spacers. Simultaneously, the LC molecules were separated from the RM molecules and formed homogenously dispersed droplets with a uniform size. The phase retardation, mechanical tolerance, and response time of the cell suggested were examined.
Efficient Ultraviolet Rotational Raman Lidar for Temperature Profiling of the Planetary Boundary Layer
Authors: Imaki Masaharu , Kawai Hisaji , Kato Tadashi , Hasegawa Toshikazu , Kobayashi Takao
Published: May 2012

An efficient rotational Raman scattering lidar using an ultraviolet-wavelength laser has been developed for temperature profile measurement of the planetary boundary layer in the lower troposphere. In this system, the high rejection of intense elastic Rayleigh and Mie backscattering was realized by a rotational Raman spectrometer using a diffraction grating and dual interference filters. Temperature measurement in thin cloud was demonstrated, and it was shown that the temperature profile obtained by lidar measurement is in good agreement with that obtained by radiosonde measurement. A statistical error of less than 1 K was obtained up to 2.5 km height in daytime measurement and up to 4.6 km height in nighttime measurement in clear air with an observation time of 16 min.
Thermo-Optical Tuning of Whispering Gallery Modes in Erbium:Ytterbium Doped Glass Microspheres to Arbitrary Probe Wavelengths
Authors: Watkins Amy , Ward Jonathan , Chormaic Síle Nic
Published: May 2012

We present experimental results on an all-optical, thermally-assisted technique for broad range tuning of microsphere cavity resonance modes to arbitrary probe wavelengths. An erbium:ytterbium co-doped phosphate glass (Schott IOG-2) microsphere is pumped at 978 nm via the supporting stem and the heat generated by absorption of the pump light expands the cavity and changes the refractive index. This is a robust tuning method that decouples the pump from the probe and allows fine tuning of the microsphere's whispering gallery modes. Pump/probe experiments were performed to demonstrate thermo-optical tuning to specific probe wavelengths, including the5S1/2F= 3 to5P3/2F'= 4 laser cooling transition of rubidium-85. This is of particular interest for cavity quantum electrodynamics (QED)-type experiments, while the broad tuning range achievable is useful for integrated photonic devices, including sensors and modulators.
Transparent Conductive Distributed Bragg Reflectors Composed of High and Low Refractive Index Transparent Conductive Films
Authors: Lee Cheng-Chung , Li Meng-Chi , Chen Sheng-Hui , Kuo Chien-Cheng
Published: May 2012

This article has shown that the co-sputtering method and post-annealing treatment have successfully fabricated the transparent conductive distributed Bragg reflectors (TCDBR). The transparent conducting film, anatase Nb-doped TiO2 (TNO), which has a high refractive index can be combined with Al-doped ZnO (AZO) low refractive index transparent conducting films to make a TCDBR capable of transferring the current from electrode to semiconductor while still maintaining the advantage for the micro resonant cavity. The eight-period stack of AZO/TNO achieves a reflectivity of up to 90% centered at 550 nm and a resistivity of 1.88×10-3 Ω cm.
Synthesis and Magnetic Properties of NiSe, NiTe, CoSe, and CoTe
Authors: Umeyama Norio , Tokumoto Madoka , Yagi Shota , Tomura Masatoshi , Tokiwa Kazuyasu , Fujii Takenori , Toda Ryo , Miyakawa Nobuaki , Ikeda Shin-Ichi
Published: May 2012

Polycrystalline NiSe, NiTe, CoSe, and CoTe have been synthesized by two methods, i.e., (1) the solid-state reaction in an evacuated quartz ampoule (QA) and (2) the high-pressure (HP) technique (HP) in a Au capsule using a cubic anvil cell. All the obtained samples have the nickel arsenide-type hexagonal crystal structure, except CoTe (HP), and their estimated lattice parameters, a and c, show almost the same values within 0.8% in comparison between samples prepared by the QA method and those by the HP method. On the other hand, a distinct difference between samples prepared by QA and HP processes is found in the magnetization of NiSe and NiTe. In particular, for NiTe, the temperature dependence of magnetization indicates two transition temperatures at about 20 and 130 K in samples prepared by the HP process. However, samples of NiTe
x
(x = 0.5, 0.66, 0.82, 1, 1.22, and 2) and NiTe containing Au prepared by QA process do not show similar magnetic orders in the temperature range between 2 and 300 K. Also, samples of NiSe (HP) show magnetic transition at ∼20 K, while those of NiSe (QA) show a magnetic inflection point at ∼10 K. To the best of our knowledge the remarkable difference in magnetic properties caused by the method of synthesis has not been reported. In this paper, we present comparative experimental results of magnetic, electric, and specific heat measurements of samples prepared by the two methods. A possible explanation for such a substantial difference in magnetic interaction will be discussed.
Quantum Transport Theory of Direct Current Conductivity in the Presence of Spin–Orbit Interaction
Authors: Kang Nam Lyong , Choi Sang Don
Published: May 2012

Utilizing the conductivity formula derived using the projection-reduction method, which combines a Kang–Choi (KC) reduction identity and a state-dependent projection operator in the linear response scheme, we investigate the effect of Rashba spin–orbit coupling on the direct current (dc) conductivity of a two-dimensional electron–phonon system when the perpendicular magnetic field is applied. A diagram representation of the formula is introduced, by which the validity of the theory is confirmed. We find that the dc conductivity oscillates with the inverse magnetic fields and the peak points of the oscillation appear near the reversion points of energy branches.
Simulation Study on Insulated Gate Bipolar Transistor Turn-Off Oscillations
Authors: Fujita Shigeto
Published: May 2012

High-frequency voltage oscillation is occasionally observed in insulated gate bipolar transistors during a turn-off operation. The turn-off oscillation generation was explained by the plasma extraction transit time oscillation theory. Its basic mechanism was the negative resistance creation. A negative RF power, which meant that the insulated gate bipolar transistor showed a “negative resistance”, was generated by the trapezoidal current density induced by holes and the RF voltage applied to the insulated gate bipolar transistor. However, the author showed that the induced current density oscillates with an almost negative phase compared with the RF voltage oscillation. He carried out an insulated gate bipolar transistor turn-off oscillation simulation using simplified simulation models. In this work, he showed the generation of the negative resistance and the turn-off oscillation in detail. He also showed the common and different points between his results and the plasma extraction transit time oscillation theory.
Buffer-Related Degradation Aspects of Single and Double-Heterostructure Quantum Well InAlN/GaN High-Electron-Mobility Transistors
Authors: Kuzmik Jan , Vitanov Stanislav , Dua Christian , Carlin Jean-Francois , Ostermaier Clemens , Alexewicz Alexander , Strasser Gottfried , Pogany Dionyz , Gornik Erich , Grandjean Nicolas , Delage Sylvain , Palankovski Vassil
Published: May 2012

We experimentally prove the viability of the concept of the double-heterostructure quantum well InAlN/GaN high-electron-mobility transistor (HEMT) for the device higher robustness and reliability. In the single quantum well InAlN/GaN HEMTs, the intrinsic channel resistance increases by 300% after 1 h off-state stress; much less degradation is observed in the double-heterostructure device with an AlGaN back barrier. Physics-based device simulation proves that the back barrier blocks the rate of carrier injection into the device buffer. However, whatever the quantum well design is, the energy of the injected electrons in the buffer of InAlN/GaN-based HEMTs is higher than that in the buffer of AlGaN/GaN HEMTs. This energy may be sufficient for releasing hydrogen from GaN point defects.
A New Two-Dimensional Analytical Threshold Voltage Model for Short-Channel Triple-Material Surrounding-Gate Metal–Oxide–Semiconductor Field-Effect Transistors
Authors: Wang Hsin-Kai , Wu Sean , Chiang Te-Kuang , Lee Maw-Shung
Published: May 2012

A new analytical model for the surface potential and threshold voltage of triple-material surrounding-gate (TM-SGT) metal–oxide–semiconductor field-effect transistors (MOSFETs) is proposed to investigate short-channel effects (SCEs). The TM-SGT MOSFET forms a two-step potential in the channel and effectively reduces the SCEs and the variation of threshold voltage compared with those of dual-material surrounding-gate (DM-SGT) and triple-material double-gate (TM-DG) MOSFETs. TM-SGT MOSFETs thus have better performance than DM-SGT and TM-DG MOSFETs.
Development of Low-Temperature Sintering Technique for Dye-Sensitized Solar Cells Combined with Dielectric Barrier Discharge Treatment
Authors: Zen Shungo , Teramoto Yoshiyuki , Ono Ryo , Oda Tetsuji
Published: May 2012

The manufacture of the dye-sensitized solar cell (DSSC) requires the sintering of TiO2 paste at 450–550 °C. High-temperature sintering is disadvantageous because it prevents the use of the materials with poor resistance to high sintering temperatures (e.g., substrate and transparent electrode). In this study, we develop a new technique of reducing the sintering temperature to 250–300 °C using dielectric barrier discharge (DBD) treatment. The DBD treatment of a 250–300 °C-sintered sample has the effects of removing the organic binder in the TiO2 paste, accelerating the necking of TiO2 nanoparticles, and chemically modifying the TiO2 surface. As a result, the energy conversion efficiency of low-temperature-sintered DSSC becomes approximately equivalent to 450–550 °C-sintered DSSCs. DBD treatment is also applied to a binder-free TiO2 paste that was developed for the low-temperature sintering of plastic substrate DSSCs. The energy conversion efficiency of the binder-free paste DSSC sintered at 150 °C is improved by a factor of 1.4 using DBD treatment.
Effect of Frequency on the Change in Backscattered Ultrasound Energy as a Function of Temperature
Authors: Tsui Po-Hsiang , Chien Yu-Ting
Published: May 2012

Clinical trials have demonstrated that hyperthermia improves cancer treatments. Previous studies have developed temperature imaging methods based on the change in the backscattered energy (CBE) of ultrasound in order to monitor temperature variations during hyperthermia. The CBE with temperature is primarily due to the temperature dependency of the backscattering coefficient, which largely depends on the ultrasound frequency. This study explored the effect of frequency on the CBE as a function of temperature. Phantom experiments involving uniform heating from 37 to 45 °C were carried out in a temperature-regulated water tank, and the raw backscattered signals were acquired using ultrasound transducers with center frequencies of 5, 10, and 15 MHz for CBE imaging. The compensation of echo shift due to temperature increase was not made for simplifying the algorithm. In the condition without motion compensation, the results showed that the absolute value of the CBE (ACBE) increases with increasing temperature. The dynamic range of the ACBE at the focus of the transducer between 37 and 45 °C increased from 5.6 to 10 dB when the ultrasound frequency increased from 5 to 15 MHz, demonstrating that the sensitivity of the CBE image in indicating the temperature variation may increase with the ultrasound frequency. However, the dynamic range of the ACBE over the same temperature range increased from only 5.5 to 6.2 dB when the CBE data were acquired from the far field of the transducer. This indicates that the beam diffraction of the transducer may reduce the dependence of the CBE on frequency, suggesting that the beam diffraction effect should be taken into account when CBE imaging employs a high-frequency transducer for sensitive temperature detection.
Tectonics of the New Guinea Region
Authors: Baldwin Suzanne L. , Fitzgerald Paul G. , Webb Laura E.
Published: May 2012

The New Guinea region evolved within the obliquely and rapidly converging Australian and Pacific plate boundary zone. It is arguably one of the most tectonically complex regions of the world, and its geodynamic evolution involved microplate formation and rotation, lithospheric rupture to form ocean basins, arc-continent collision, subduction polarity reversal, collisional orogenesis, ophiolite obduction, and exhumation of (ultra)high-pressure metamorphic rocks. We describe the major onshore and offshore tectonic and geologic components, including plate boundaries, seismicity, faults, and magmatism, and we integrate these with emerging ideas about mantle dynamics to evaluate the Cenozoic tectonic evolution of New Guinea. Future research opportunities to resolve the mantle structure beneath New Guinea will enable mantle dynamics to be linked to lithospheric and surface processes. Virtually all plate tectonic and mantle processes have been active in the New Guinea region throughout the Cenozoic, and, as such, its tectonic evolution has global significance.
Archean Subduction: Fact or Fiction?
Authors: van Hunen Jeroen , Moyen Jean-François
Published: May 2012

Subduction drives plate tectonics and builds continental crust, and as such is one of the most important processes for shaping the present-day Earth. Here we review both theory and observations for the viability and style of Archean subduction. High Archean mantle temperature gave low mantle viscosity and affected plate strength and plate buoyancy. This resulted in slower or intermittent subduction, either of which resulted in Earth cooling profiles that fit available data. Some geological observations are interpreted as subduction related, including an “arc” signature in various igneous rocks (suggesting burial of surface material to depths of 50–100 km), structural thrust belts and dipping seismic reflectors, and high-pressure–low-temperature and low-pressure–high-temperature paired metamorphic belts. Combined geodynamical and geochemical evidence suggests that subduction operated in the Archean, although not, as often assumed, as shallow flat subduction. Instead, subduction was more episodic in nature, with more intermittent plate motion than in the Phanerozoic.
Processes on the Young Earth and the Habitats of Early Life
Authors: Arndt Nicholas T. , Nisbet Euan G.
Published: May 2012

Conditions at the surface of the young (Hadean and early Archean) Earth were suitable for the emergence and evolution of life. After an initial hot period, surface temperatures in the late Hadean may have been clement beneath an atmosphere containing greenhouse gases over an ocean-dominated planetary surface. The first crust was mafic and it internally melted repeatedly to produce the felsic rocks that crystallized the Jack Hills zircons. This crust was destabilized during late heavy bombardment. Plate tectonics probably started soon after and had produced voluminous continental crust by the mid Archean, but ocean volumes were sufficient to submerge much of this crust. In the Hadean and early Archean, hydrothermal systems around abundant komatiitic volcanism may have provided suitable sites to host the earliest living communities and for the evolution of key enzymes. Evidence from the Isua Belt, Greenland, suggests life was present by 3.8 Gya, and by the mid-Archean, the geological record both in the Pilbara in Western Australia and the Barberton Greenstone Belt in South Africa shows that microbial life was abundant, probably using anoxygenic photosynthesis. By the late Archean, oxygenic photosynthesis had evolved, transforming the atmosphere and permitting the evolution of eukaryotes.
The Compositions of Kuiper Belt Objects
Authors: Brown Michael E.
Published: May 2012

Objects in the Kuiper belt are difficult to study in detail, even with the best telescopes available. Therefore, for many years, studies of the compositions of these objects were relegated to collections of moderate-quality spectroscopic and photometric data that remained difficult to interpret. Much early effort was put into simple correlations of surface colors and identifications of spectral features, but connecting these observations to a larger understanding of the region remained elusive. The past decade, however, has seen a blossoming in our understanding, a product of the discoveries of larger—and thus easier to study—objects, continued collection of high-quality photometric and spectroscopic observations, and continued work at the laboratory and theoretical levels. Today, we now know of many processes that affect these objects' surface compositions, including atmospheric loss, differentiation and cryovolcanism, radiation processing, the effects of giant impacts, and the early dynamical excitation of the Kuiper belt. I review the large quantity of data now available and attempt to build a comprehensive framework for understanding the compositions and their causes.
History of Seawater Carbonate Chemistry, Atmospheric CO2, and Ocean Acidification
Authors: Zeebe Richard E.
Published: May 2012

Humans are continuing to add vast amounts of carbon dioxide (CO2) to the atmosphere through fossil fuel burning and other activities. A large fraction of the CO2is taken up by the oceans in a process that lowers ocean pH and carbonate mineral saturation state. This effect has potentially serious consequences for marine life, which are, however, difficult to predict. One approach to address the issue is to study the geologic record, which may provide clues about what the future holds for ocean chemistry and marine organisms. This article reviews basic controls on ocean carbonate chemistry on different timescales and examines past ocean chemistry changes and ocean acidification events during various geologic eras. The results allow evaluation of the current anthropogenic perturbation in the context of Earth's history. It appears that the ocean acidification event that humans are expected to cause is unprecedented in the geologic past, for which sufficiently well-preserved records are available.
Tracing Crustal Fluids: Applications of Natural129I and36Cl
Authors: Fehn Udo
Published: May 2012

The two cosmogenic isotopes129I and36Cl have half-lives and geochemical characteristics that make their application of interest in the tracing of crustal fluids, oil field brines, and geothermal fluids. The focus of this review is to compare129I data from volcanic fluids with those from mud volcanoes and gas hydrate locations associated with the same subduction zone in order to demonstrate that fundamentally different hydrologic systems are present in active margins. Whereas129I/I ratios in volcanic fluids are site dependent and show a relation to the ages of subducting marine sediments, ratios in fore arc fluids are similar in all sites investigated and are independent of the ages of the host sediments and the age of the subducting slab. Volcanic fluids contain iodine transported in sediments from the trench to the main volcanic zone, whereas iodine in fore arc fluids is derived from organic material stored in the upper plates of subduction zones.
Satellite Geomagnetism
Authors: Olsen Nils , Stolle Claudia
Published: May 2012

Observations of Earth's magnetic field from space began more than 50 years ago. A continuous monitoring of the field using low Earth orbit (LEO) satellites, however, started only in 1999, and three satellites have taken high-precision measurements of the geomagnetic field during the past decade. The unprecedented time-space coverage of their data opened revolutionary new possibilities for monitoring, understanding, and exploring Earth's magnetic field. In the near future, the three-satellite constellation Swarm will ensure continuity of such measurement and provide enhanced possibilities to improve our ability to characterize and understand the many sources that contribute to Earth's magnetic field. In this review, we summarize investigations of Earth's interior and environment that have been possible through the analysis of high-precision magnetic field observations taken by LEO satellites.
Mixing and Transport of Isotopic Heterogeneity in the Early Solar System
Authors: Boss Alan P.
Published: May 2012

Isotopic abundances of short-lived radioisotopes such as 26Al appear to provide precise chronometers of events in the early Solar System, assuming that they were initially homogeneously distributed. However, both 60Fe and 26Al were likely formed in a supernova and then injected into the solar nebula in a highly heterogeneous manner. Conversely, the abundances in primitive meteorites of the three stable oxygen isotopes exhibit mass-independent fractionations that somehow survived homogenization in the solar nebula. Both the presence of refractory particles in Comet 81P/Wild 2 and the anomalously high crystallinity observed in protoplanetary disks may require large-scale outward radial transport from the hotter inner disk regions, even as disk gas accretes onto the central protostar. We examine here theoretical efforts to solve these seemingly disparate cosmochemical puzzles and conclude that the mixing and transport produced by a phase of marginal gravitational instability appears to meet all of these constraints.
Geophysics of Chemical Heterogeneity in the Mantle
Authors: Stixrude Lars , Lithgow-Bertelloni Carolina
Published: May 2012

Chemical heterogeneity, produced by the near-surface rock cycle and dominated volumetrically by subducted oceanic crust and its depleted residue, is continuously subducted into the mantle. This lithologic-scale chemical heterogeneity may survive in the mantle for as long as the age of Earth because chemical diffusion is inefficient. Estimates of rates of subduction and mantle processing over geologic history indicate that most or all of the mantle may be composed of lithologically heterogeneous material. Mineralogical models of the mantle show that chemical heterogeneity over many decades in length scale may be detectable by geophysical probes via its influence on seismic-wave propagation. Grain-scale heterogeneity influences the aggregate absolute seismic velocity and its lateral variation with temperature. The elastic-wave velocity contrast associated with lithologic-scale heterogeneity may be sufficient to produce observable scattering of short-period seismic waves.
Central versus peripheral impact of estradiol on the impaired glucose metabolism in ovariectomized mice on a high-fat diet
Authors: Yonezawa Rika , Wada Tsutomu , Matsumoto Natsumi , Morita Mayuko , Sawakawa Kanae , Ishii Yoko , Sasahara Masakiyo , Tsuneki Hiroshi , Saito Shigeru , Sasaoka Toshiyasu
Published: May 2012

Age-related loss of ovarian function promotes adiposity and insulin resistance in women. Estrogen (E2) directly enhances insulin sensitivity and suppresses lipogenesis in peripheral tissues. Recently, the central actions of E2 in the regulation of energy homeostasis are becoming clearer; however, the functional relevance and degree of contribution of the central vs. peripheral actions of E2 are currently unknown. Therefore, we prepared and analyzed four groups of mice. 1) Control: sham-operated mice fed a regular diet, 2) OVX-HF: ovariectomized (OVX) mice fed a 60% high-fat diet (HF), 3) E2-SC: OVX-HF mice subcutaneously treated with E2, and 4) E2-ICV: OVX-HF mice treated with E2 intracerebroventricularly. OVX-HF mice showed increased body weight with both visceral and subcutaneous fat volume enlargement, glucose intolerance, and insulin resistance. Both E2-SC and E2-ICV equally ameliorated these abnormalities. Although the size of adipocytes and number of CD11c-positive macrophages in perigonadal fat in OVX-HF were reduced by both E2 treatments, peripherally administered E2 decreased the expression of TNFα, lipoprotein lipase, and fatty acid synthase in the white adipose tissue (WAT) of OVX-HF. In contrast, centrally administered E2 increased hormone-sensitive lipase in WAT, decreased the hepatic expression of gluconeogenic enzymes, and elevated core body temperature and energy expenditure with marked upregulation of uncoupling proteins in the brown adipose tissue. These results suggest that central and peripheral actions of E2 regulate insulin sensitivity and glucose metabolism via different mechanisms, and their coordinated effects may be important to prevent the development of obesity and insulin resistance in postmenopausal women.
Skeletal muscle nitric oxide signaling and exercise: a focus on glucose metabolism
Authors: McConell Glenn K. , Rattigan Stephen , Lee-Young Robert S. , Wadley Glenn D. , Merry Troy L.
Published: May 2012

Nitric oxide (NO) is an important vasodilator and regulator in the cardiovascular system, and this link was the subject of a Nobel prize in 1998. However, NO also plays many other regulatory roles, including thrombosis, immune function, neural activity, and gastrointestinal function. Low concentrations of NO are thought to have important signaling effects. In contrast, high concentrations of NO can interact with reactive oxygen species, causing damage to cells and cellular components. A less-recognized site of NO production is within skeletal muscle, where small increases are thought to have beneficial effects such as regulating glucose uptake and possibly blood flow, but higher levels of production are thought to lead to deleterious effects such as an association with insulin resistance. This review will discuss the role of NO in skeletal muscle during and following exercise, including in mitochondrial biogenesis, muscle efficiency, and blood flow with a particular focus on its potential role in regulating skeletal muscle glucose uptake during exercise.
Increased susceptibility to kidney injury by transfer of genomic segment from SHR onto Dahl S genetic background
Authors: Regner Kevin R. , Harmon Ashlyn C. , Williams Jan M. , Stelloh Cary , Johnson Ashley C. , Kyle Patrick B. , Lerch-Gaggl Alexandra , White Sarah M. , Garrett Michael R.
Published: May 2012

The Dahl salt-sensitive (S) rat is a widely studied model of salt-sensitive hypertension and develops proteinuria, glomerulosclerosis, and renal interstitial fibrosis. An earlier genetic analysis using a population derived from the S and spontaneously hypertensive rat (SHR) identified eight genomic regions linked to renal injury in the S rat and one protective locus on chromosome 11. The “protective” locus in the S rat was replaced with the SHR genomic segment conferring “susceptibility” to kidney injury. The progression of kidney injury in the S.SHR( 11 ) congenic strain was characterized in the present study. Groups of S and S.SHR( 11 ) rats were followed for 12 wk on either a low-salt (0.3% NaCl) or high-salt (2% NaCl) diet. By week 12 (low-salt), S.SHR( 11 ) demonstrated a significant decline in kidney function compared with the S. Blood pressure was significantly elevated in both strains on high salt. Despite similar blood pressure, the S.SHR( 11 ) exhibited a more significant decline in kidney function compared with the S. The decline in S.SHR( 11 ) kidney function was associated with more severe kidney injury including tubular loss, immune cell infiltration, and tubulointerstitial fibrosis compared with the S. Most prominently, the S.SHR( 11 ) exhibited a high degree of medullary fibrosis and a significant increase in renal vascular medial hypertrophy. In summary, genetic modification of the S rat generated a model of accelerated renal disease that may provide a better system to study progression to renal failure as well as lead to the identification of genetic variants involved in kidney injury.
Application of Electrocoagulation Process Using Iron and Aluminum Electrodes for Fluoride Removal from Aqueous Environment
Authors: Bazrafshan Edris , Ownagh Kamal Aldin , Mahvi Amir Hossein
Published: May 2012

Fluoride in drinking water above permissible level is responsible for human being affected by skeletal fluorosis. The present study was carried out to assess the ability of electrocoagulation process with iron and aluminum electrodes in order to removal of fluoride from aqueous solutions. Several working parameters, such as fluoride concentration, pH, applied voltage and reaction time were studied to achieve a higher removal capacity. Variable concentrations (1, 5 and 10 mg L-1) of fluoride solutions were prepared by mixing proper amount of sodium fluoride with deionized water. The varying pH of the initial solution (3, 7 and 10) was also studied to measure their effects on the fluoride removal efficiency. Results obtained with synthetic solution revealed that the most effective removal capacities of fluoride could be achieved at 40 V electrical potential. In addition, the increase of electrical potential, in the range of 10‐40 V, enhanced the treatment rate. Also comparison of fluoride removal efficiency showed that removal efficiency is similar with iron and aluminum electrodes. Finally it can be concluded that the electrocoagulation process has the potential to be utilized for the cost‐effective removal of fluoride from water and wastewater.
Experimental and Theoretical Studies of Ultrasonic Velocityin Binary Liquid Mixtures of Ethyl benzoate
Authors: Babu Shaik , Sastry S. V. Kumara , Tiong Ha Sie , Sastry S. Sreehari
Published: May 2012

Ultrasonic velocity is measured at 2MHz frequency in the binary mixtures of Ethyl Benzoate with 1‐Propanol, 1‐Butanol, 1‐Pentanol and theoretical values of ultrasonic velocity have been evaluated at 303K using Nomoto′s relation, Impedance relation, Ideal mixture relation, Junjie′s method and free length theory. Theoretical values are compared with the experimental values and the validity of the theories is checked by applying the chi‐square test for goodness of fit and by calculating the average percentage error (APE). A good agreement has been found between experimental and Nomoto’s ultrasonic velocity.
Kinetics and Equilibrium Studies on Adsorption of Acid Red 18 (Azo‐Dye) Using Multiwall Carbon Nanotubes (MWCNTs) from Aqueous Solution
Authors: Shirmardi Mohammad , Mesdaghinia Alireza , Mahvi Amir Hossein , Nasseri Simin , Nabizadeh Ramin
Published: May 2012

Azo dyes are one of the synthetic dyes that are used in many textile industries. Adsorption is one of the most effective techniques for removal of dye‐contaminated wastewater. In this work, efficiency of multiwalled carbon nanotubes (MWCNTs) as an adsorbent for removal of Acid Red 18 (azo‐dye) from aqueous solution was determined. The parameters affecting the adsorption process such as contact time, pH, adsorbent dosage, and initial dye concentration were studied. Experimental results have shown by increasing the adsorbent dosage, the rate of dye removal was increased, but the amount of adsorbed dyes per mass unit of MWCNTs was declined. pH as one of the most important influencing factors on the adsorption process was evaluated. The best pH for adsorption process was acidic pH of about 3. To describe the equilibrium of adsorption, the Langmuir, Freundlich and Temkin isotherms were used. The Langmuir isotherm (R2=0.985) was the best fitted for experimental data with maximum adsorption capacity of 166.67 mg/g. A higher correlation value of the kinetic′s model was observed close to pseudo second order (R2=0.999) compared to other kinetic models.
Trichloroisocyanuric acid, a New and Efficient Catalyst for the Synthesis of 2′‐ Aminobenzothiazolo‐arylmethyl‐2‐naphthols
Authors: Yang Limin
Published: May 2012

An efficient one‐pot synthesis of 2′‐aminobenzothiazolo‐arylmethyl‐2‐naphthols is described. This involves the three‐component reaction of β‐naphthol, aromatic aldehydes and 2‐aminobenzothiazole in the presence of a catalytic amount of trichloroisocyanuric acid under solvent‐free conditions.
Synthesis and Characterisation of Penta‐Bismuth Hepta‐Oxide Nitrate, Bi5O7NO3, as a New Adsorbent for Methyl Orange Removal from an Aqueous Solution
Authors: Abdullah Eshraq Ahmed , Abdullah Abdul Halim , Zainal Zulkarnain , Hussein Mohd Zobir , Ban Tan Kar
Published: May 2012

This paper presents the synthesis of penta‐bismuth hepta‐oxide nitrate, Bi5O7NO3, via the chemical precipitation method. After calcination, the precipitate was characterised by several methods, which included X‐ray powder diffraction, X‐ray photoelectron spectroscopy, scanning and transmission electron microscopy, Fourier transform infrared, thermogravimetric analysis, BET surface area and pH drift method to determine the pH of point of zero charge (pHpzc). The study results revealed that Bi5O7NO3 had an orthorhombic crystal structure, a surface area of 1.6 m2 g‐1 and a point of zero charge at pH 9.7. The chemical state of Bi5O7NO3 indicated the presence of three oxidation states of bismuth centre. Furthermore, the decolourization ability of Bi5O7NO3 to remove the azo dye was also evaluated. Although it had lower surface area, the removal efficiency was extremely good. This finding suggests that Bi5O7NO3 could be used as a promising adsorbent for azo dye removal. The XPS spectra showed that the accumulation of dye onto Bi5O7NO3 could be due to the anion exchange process, suggesting the birth of a new anion exchanger for azo dye removal.
Nitrogen-Doped TiO2Nanotube Arrays with Enhanced Photoelectrochemical Property
Authors: Li Shipu , Lin Shiwei , Liao Jianjun , Pan Nengqian , Li Danhong , Li Jianbao
Published: May 2012

N-doped TiO2nanotube arrays were prepared by electrochemical anodization in glycerol electrolyte, followed by electrochemical deposition in NH4Cl solution. An orthogonal experiment was used to optimize the doping conditions. Electrolyte concentration, reaction voltage, and reaction time were the main factors to influence the N-doping effect which was the determinant of the visible range photoresponse. The optimal N-doping conditions were determined as follows: reaction voltage is 3 V, reaction time is 2 h, and electrolyte concentration is 0.5 M. The maximal photocurrent enhanced ratio was 30% under white-light irradiation. About 58% improvement of photocatalytic efficiency was achieved in the Rhodamine B degradation experiment by N doping. The kinetic constant of the N-doped TNT arrays sample was almost twice higher than that of the undoped sample. Further analysis by X-ray photoelectron spectroscopy supported that electrochemical deposition is a simple and efficient method for N doping into TiO2nanotube arrays.