bluuebunny/crossref_metadata_2025 huggingface dataset:
Finite-Difference Time-Domain Analysis of Twist-Defect-Mode Lasing Dynamics in Cholesteric Photonic Liquid Crystal
Authors: Matsui Tatsunosuke , Kitaguchi Masahiro
Published: April 2012

We have numerically investigated lasing dynamics from a twist defect in a cholesteric liquid crystal (CLC) by an auxiliary differential equation finite-difference time-domain (ADE-FDTD) method. As ADEs, the equation of motion of polarization described on the basis of the classical electron oscillator (Lorenz) model and the rate equation in a four-level energy structure are incorporated. A lower lasing threshold has been obtained from the twist-defect mode (TDM) than from band-edge lasing. Standing-wave-like electric fields are strongly localized only in the vicinity where a twist defect is introduced into a CLC, which works as a distributed feedback TDM laser source. The oscillation direction of a standing-wave electric field is not parallel or perpendicular to LC molecules, which is quite different from the bulk CLC case. Our results may be useful for creating more efficient TDM-based CLC lasers.
Analysis of the Performance of an Inverter Circuit: Varying the Thickness of the Active Layer in Polymer Thin Film Transistors with Circuit Simulation
Authors: Reséndiz Luis , Estrada Magali , Cerdeira Antonio , Cabrera Víctor
Published: April 2012

In this paper, we study, through simulation, the effects on the behavior of an inverter circuit when the active layer thickness of the polymer thin film transistor design is modified. A previously developed compact model for polymer transistors was implemented in standardized hardware description language. We validate results with measured characteristics of transistors fabricated with a poly(methyl methacrylate) layer on top of a poly(3-hexylthiophene-2,5-diyl). This analysis indicates that decreasing the thickness of the active layer can increase the output voltage swing and hence the noise margin in digital circuits. Higher noise margin and larger gain were found for inverters with active layer thicknesses less than 40 nm.
Structural and Molecular Changes of C60 Thin Films with Incorporated Magnesium Atoms
Authors: Morales Crisóforo , Kojima Nobuaki , Nishi Seiji , Yamaguchi Masafumi
Published: April 2012

Crystalline changes determined from the diffraction patterns of X-rays in C60 films were observed when magnesium atoms were incorporated into C60 films grown on mica substrates. The low full width at half maximum (FWHM) value for Mg-doped C60 on the mica substrate indicates the high crystalline quality at low magnesium concentrations. Infrared modes that were initially inactive became active owing to the interaction of magnesium atoms with the C60 molecule cage. The presence of the lines of triangular cyclic trimers suggests the presence of partially decomposed rhombohedral and rhombohedral polymers. Intermolecular bonds formed owing to the formation of polymeric phases in the film are responsible for the crystalline quality deterioration.
Organic Solar Cells Based on Electrodeposited Polyaniline Films
Authors: Inoue Kei , Akiyama Tsuyoshi , Suzuki Atsushi , Oku Takeo
Published: April 2012

Polyaniline thin films as hole transporting layers were fabricated on transparent indium–tin-oxide electrodes by electrodeposition of aniline in an aqueous H2SO4 electrolyte solution. Emerald-green polyaniline films were obtained, which showed stable redox waves. A mixed solution of polythiophene and fullerene derivative was spin-coated onto the electrodeposited polyaniline film. After the modification of titanium oxide film on the surface of the polythiophene/fullerene layer, an aluminum electrode was fabricated by vacuum deposition. The obtained solar cells generated stable photocurrent and photovoltage under light illumination.
Sub-micro-liter Electrochemical Single-Nucleotide-Polymorphism Detector for Lab-on-a-Chip System
Authors: Tanaka Hiroyuki , Fiorini Paolo , Peeters Sara , Majeed Bivragh , Sterken Tom , Beeck Maaike Op de , Hayashi Miho , Yaku Hidenobu , Yamashita Ichiro
Published: April 2012

A sub-micro-liter single-nucleotide-polymorphism (SNP) detector for lab-on-a-chip applications is developed. This detector enables a fast, sensitive, and selective SNP detection directly from human blood. The detector is fabricated on a Si substrate by a standard complementary metal oxide semiconductor/micro electro mechanical systems (CMOS/MEMS) process and Polydimethylsiloxane (PDMS) molding. Stable and reproducible measurements are obtained by implementing an on-chip Ag/AgCl electrode and encapsulating the detector. The detector senses the presence of SNPs by measuring the concentration of pyrophosphoric acid generated during selective DNA amplification. A 0.5-µL-volume detector enabled the successful performance of the typing of a SNP within the ABO gene using human blood. The measured sensitivity is 566 pA/µM.
Analysis of Sharp Dip Structures on Terahertz Transmission Spectra of Metallic Meshes
Authors: Hasebe Takayuki , Yamada Yuki , Tabata Hitoshi
Published: April 2012

Metallic meshes are designed for anomalous transmission phenomena in the THz region, which originates from the two contributions: one involves the surface waves excitations generated through periodically arranged metal holes, the other involves the half-wavelength resonance of the metal hole. Furthermore, metallic meshes are used to observe the sharp dip in the transmission spectrum. The sharp dip structure is very sensitive to change in the refractive index of materials attached on metallic meshes. However, the origin of the dip structure is still unclear. In this work, we investigate optical response of the dip structure in the THz region from experimental and theoretical viewpoints. It is found that the dip structure is related to cutoff frequency in the electric field distribution based on a transverse electric 11 (TE11) mode of the rectangular waveguide. Finally, we suggest a theoretical equation in order to explain the dip structure.
Anisotropic Weak Anti-Localization under In-Plane Magnetic Field and Control of Dimensionality via Spin Precession Length
Authors: Nonaka Shun , Kunihashi Yoji , Kohda Makoto , Nitta Junsaku
Published: April 2012

We have examined the newly proposed method in order to electrically deduce the ratio between the Rashba and Dresselhaus spin–orbit interaction (SOI) parameters. Anisotropic magneto-conductance in gate-fitted InGaAs narrow wires is observed under an in-plane magnetic field. From the comparison between experiments and calculated Rashba SOI parameters, we have found that the method is applicable only when the wire width is shorter than the spin precession length. A transition from narrow wires to two-dimensional (2D) wires is observed both by decreasing the spin precession length and by increasing wire width.
Temperature Dependence of Spin Relaxation Time in InAs Columnar Quantum Dots at 10 to 150 K
Authors: Nakanishi Sota , Sasayama Kazutoshi , Oyanagi Yoshitsugu , Yamaguchi Ryo , Lu Shulong , Li Lianhe , Fiore Andrea , Tackeuchi Atsushi
Published: April 2012

We have investigated carrier spin relaxation in InAs columnar quantum dots (CQDs) using time-resolved photoluminescence measurement. The CQDs were formed by depositing a 1.8 monolayer InAs seed dot layer and a short-period GaAs/InAs superlattice (SL). The spin relaxations of the 3- and 35-period SL CQDs show double exponential decay up to 50 and 130 K, respectively. The spin relaxation times of the fast component, whose amplitudes are 4–11 times larger than that of the slow component, are around 100 ps for the two samples. For the 3-period SL CQDs, the fast spin relaxation time shows no temperature dependence up to around 50 K, indicating the relevance of the Bir-Aronov-Pikus process. The slow spin relaxation time of the 35-period SL CQDs was found to decrease from 3.42 ns at 10 K to 0.849 ns at 130 K. This large change may be explained by the Elliott–Yafet process considering acoustic phonon scattering.
Direct Growth Properties of Graphene Layers on Sapphire Substrate by Alcohol-Chemical Vapor Deposition
Authors: Nakamura Atsushi , Miyasaka Yuta , Temmyo Jiro
Published: April 2012

Few nanometers thick graphene layers were directly grown on a-plane (112̄0) sapphire substrates by alcohol-chemical vapor deposition (alcohol-CVD) using ethanol as a carbon source and without any catalytic metal on the substrate surface. The growth relationship between the graphene layer and substrate was analyzed using a transmission electron microscope (TEM). The growth rate of graphene layers with different growth temperatures revealed that the Al atom act as a catalyst for synthesizing a graphitic material during the decomposition of ethanol. An optical transmittance and a sheet resistance of the graphene sheet directly grown on sapphire substrate were observed. SiO2/Si and n-6H-SiC substrates were also examined for graphene direct growth to discuss the catalytic behavior of Si atoms compared with Al atoms.
Reduction of Power Loss of Zero Current Switching Converter by Optimizing Power Devices
Authors: Machida Satoru , Kikuchi Naoto , Segawa Tsutomu , Shimo Yuichi , Kobayashi Masashi
Published: April 2012

This paper reports on a reduction of the power loss of the zero current switching (ZCS) converter by the power switching devices, the main and auxiliary switch (Si-IGBT), for the first time. The origin of a “current spike” which was observed during ZCS turn-off was investigated, and it was found that this distinctive phenomenon can be eliminated by shortening the turn-off time of main switch. An improvement of the switching loss reduction rate of a hard switching (HS) can be realized by selecting an optimal turn-off time of the main switch. In addition, the optimal turn-off time varies and has a strong correlation with the turn-off time of the auxiliary switch. It became clear that there is an optimal combination in the characteristics of the switching devices of the ZCS. It was confirmed that the power loss of the ZCS was improved by 17% by this power device optimization.
Surface Recombination of Crystalline Silicon Substrates Passivated by Atomic-Layer-Deposited AlOx
Authors: Arafune Koji , Miki Shohei , Matsutani Ryosuke , Hamano Junpei , Yoshida Haruhiko , Tachibana Tomihisa , Lee Hyun Ju , Ogura Atsuhi , Ohshita Yoshio , Satoh Shin-ichi
Published: April 2012

AlO
x
films as passivation layers for p-type crystalline silicon were prepared by atomic layer deposition with ozone as an oxidant, and the effects of the AlO
x
film thickness and deposition temperature on the maximum recombination velocity (S
max) were evaluated. S
max is improved by increasing the layer thickness but saturates at a layer thickness of about 30 nm. In the case of samples deposited at room temperature, S
max is improved fivefold when the thickness is increased from 20 to 33 nm. S
max also improved as the deposition temperature was increased to 300 °C then deteriorated when it was further increased to 350 °C. After postdeposition annealing, we obtained an S
max of 8.5 cm/s.
Investigation of Hot Carrier Degradation in Shallow-Trench-Isolation-Based High-Voltage Laterally Diffused Metal–Oxide–Semiconductor Field-Effect Transistors by a Novel Direct Current Current–Voltage Technique
Authors: He Yandong , Zhang Ganggang
Published: April 2012

Shallow trench isolation (STI) based laterally diffused metal–oxide–semiconductor (LDMOS) devices have become popular with its better tradeoff between breakdown voltage and on-resistance and its compatibility with the standard complementary metal–oxide–semiconductor (CMOS) process. A novel direct current current–voltage (DCIV) technique demonstrated with multiple sharp peak signals is proposed to characterize interface state generation in the channel and in the STI drift regions separately. Degradation of STI-based LDMOS transistors in various hot-carrier stress modes is investigated experimentally by proposed technique. A two-dimensional numerical device simulation is performed to obtain insight into the proposed technique and device degradation characteristics under hot-carrier stress conditions. The impact of interface state location on device electrical characteristics is analyzed from measurement and simulation. Our results show that the maximum I
sub stress becomes the worst hot-carrier degradation mode in term of the on-resistance degradation, which is attributed to interface state generation under STI drift region.
Current Transport Characteristics of Quasi-AlxGa1-xN/SiC Heterojunction Bipolar Transistors with Various Band Discontinuities
Authors: Okuda Takafumi , Miyake Hiroki , Kimoto Tsunenobu , Suda Jun
Published: April 2012

The current transport characteristics of quasi-Al
x
Ga1-x
N/SiC heterojunction bipolar transistors (HBTs) with various band discontinuities were investigated in a low-current range using a Gummel plot. In the low-current range, the base currents of the HBTs were dominated by recombination currents. The collector current characteristics of the HBTs in the low-current range were almost the same in spite of the various band discontinuities, and the ideality factor n was 1.0. The band discontinuities at the heterojunction had no effect on electron injection in the low-current range. This is because the collector currents were dominated by diffusion process in the base region rather than by injection process at the AlGaN/SiC interface.
Proton block of the pore underlies the inhibition of hERG cardiac K+ channels during acidosis
Authors: Van Slyke Aaron C. , Cheng Yen May , Mafi Pouya , Allard Charlene R. , Hull Christina M. , Shi Yu Patrick , Claydon Tom W.
Published: April 2012

Human ether-a-go-go-related gene (hERG) potassium channels are critical determinants of cardiac repolarization. Loss of function of hERG channels is associated with Long QT Syndrome, arrhythmia, and sudden death. Acidosis occurring as a result of myocardial ischemia inhibits hERG channel function and may cause a predisposition to arrhythmias. Acidic pH inhibits hERG channel maximal conductance and accelerates deactivation, likely by different mechanisms. The mechanism underlying the loss of conductance has not been demonstrated and is the focus of the present study. The data presented demonstrate that, unlike in other voltage-gated potassium (Kv) channels, substitution of individual histidine residues did not abolish the pH dependence of hERG channel conductance. Abolition of inactivation, by the mutation S620T, also did not affect the proton sensitivity of channel conductance. Instead, voltage-dependent channel inhibition (δ = 0.18) indicative of pore block was observed. Consistent with a fast block of the pore, hERG S620T single channel data showed an apparent reduction of the single channel current amplitude at low pH. Furthermore, the effect of protons was relieved by elevating external K+ or Na+ and could be modified by charge introduction within the outer pore. Taken together, these data strongly suggest that extracellular protons inhibit hERG maximal conductance by blocking the external channel pore.
Calcium-sensing receptor inhibits secretagogue-induced electrolyte secretion by intestine via the enteric nervous system
Authors: Cheng Sam X.
Published: April 2012

Bacterial toxins such as cholera toxin induce diarrhea by both direct epithelial cell generation of cyclic nucleotides as well as stimulation of the enteric nervous system (ENS). Agonists of the extracellular calcium-sensing receptor (CaSR) can reduce toxin-stimulated fluid secretion in ENS-absent colonic epithelial crypts by increasing phosphodiesterase-dependent cyclic-nucleotide degradation. Here we show that the CaSR is also highly expressed in tetrodotoxin (TTX)-sensitive neurons comprising the ENS, suggesting that CaSR agonists might also function through neuronal pathways. To test this hypothesis, rat colon segments containing intact ENS were isolated and mounted on Ussing chambers. Basal and cyclic nucleotide-stimulated electrolyte secretions were monitored by measuring changes in short-circuit current ( Isc). CaSR was activated by R-568 and its effects were compared in the presence and absence of TTX. Consistent with active regulation of anion secretion by the ENS, a significant proportion of Isc in the proximal and distal colon was inhibited by serosal TTX, both at basal and under cyclic AMP-stimulated conditions. In the absence of TTX, activation of CaSR with R-568 significantly reduced basal Isc and cyclic AMP-stimulated Isc; it also completely reversed the cAMP-stimulated secretory responses if the drug was applied after the forskolin stimulation. Such inhibitory effects of R-568 were either absent or significantly reduced when serosal TTX was present, suggesting that this agonist exerts its antisecretory effect on the intestine by inhibiting ENS. The present results suggest a new model for regulating intestinal fluid transport in which neuronal and nonneuronal secretagogue actions are modulated by the inhibitory effects of CaSR on the ENS. The ability of a CaSR agonist to reduce secretagogue-stimulated Cl− secretion might provide a new therapeutic approach for secretory and other ENS-mediated diarrheal conditions.
Impaired ghrelin signaling is associated with gastrointestinal dysmotility in rats with gastroesophageal reflux disease
Authors: Nahata Miwa , Muto Shuichi , Oridate Nobuhiko , Ohnishi Shunsuke , Nakagawa Koji , Sadakane Chiharu , Saegusa Yayoi , Hattori Tomohisa , Asaka Masahiro , Takeda Hiroshi
Published: April 2012

Gastroesophageal reflux disease (GERD) is often associated with decreased upper gastrointestinal motility, and ghrelin is an appetite-stimulating hormone known to increase gastrointestinal motility. We investigated whether ghrelin signaling is impaired in rats with GERD and studied its involvement in upper gastrointestinal motility. GERD was induced surgically in Wistar rats. Rats were injected intravenously with ghrelin (3 nmol/rat), after which gastric emptying, food intake, gastroduodenal motility, and growth hormone (GH) release were investigated. Furthermore, plasma ghrelin levels and the expression of ghrelin-related genes in the stomach and hypothalamus were examined. In addition, we administered ghrelin to GERD rats treated with rikkunshito, a Kampo medicine, and examined its effects on gastroduodenal motility. GERD rats showed a considerable decrease in gastric emptying, food intake, and antral motility. Ghrelin administration significantly increased gastric emptying, food intake, and antral and duodenal motility in sham-operated rats, but not in GERD rats. The effect of ghrelin on GH release was also attenuated in GERD rats, which had significantly increased plasma ghrelin levels and expression of orexigenic neuropeptide Y/agouti-related peptide mRNA in the hypothalamus. The number of ghrelin-positive cells in the gastric body decreased in GERD rats, but the expression of gastric preproghrelin and GH secretagogue receptor mRNA was not affected. However, when ghrelin was exogenously administered to GERD rats treated with rikkunshito, a significant increase in antral motility was observed. These results suggest that gastrointestinal dysmotility is associated with impaired ghrelin signaling in GERD rats and that rikkunshito restores gastrointestinal motility by improving the ghrelin response.
A model of preeclampsia in rats: the reduced uterine perfusion pressure (RUPP) model
Authors: Li Jing , LaMarca Babbette , Reckelhoff Jane F.
Published: April 2012

Preeclampsia is defined as new-onset hypertension with proteinuria after 20 wk gestation and is hypothesized to be due to shallow trophoblast invasion in the spiral arteries thus resulting in progressive placental ischemia as the fetus grows. Many animal models have been developed that mimic changes in maternal circulation or immune function associated with preeclampsia. The model of reduced uterine perfusion pressure in pregnant rats closely mimics the hypertension, immune system abnormalities, systemic and renal vasoconstriction, and oxidative stress in the mother, and intrauterine growth restriction found in the offspring. The model has been successfully used in many species; however, rat and primate are the most consistent in comparison of characteristics with human preeclampsia. The model suffers, however, from lack of the ability to study the mechanisms responsible for abnormal placentation that ultimately leads to placental ischemia. Despite this limitation, the model is excellent for studying the consequences of reduced uterine blood flow as it mimics many of the salient features of preeclampsia during the last weeks of gestation in humans. This review discusses these features.
Resistance exercise load does not determine training-mediated hypertrophic gains in young men
Authors: Mitchell Cameron J. , Churchward-Venne Tyler A. , West Daniel W. D. , Burd Nicholas A. , Breen Leigh , Baker Steven K. , Phillips Stuart M.
Published: April 2012

We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 ± 1 yr, 22.6 ± 2.1 kg/m2; means ± SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant ( P < 0.01), with no difference between groups: 30%-3 = 6.8 ± 1.8%, 80%-1 = 3.2 ± 0.8%, and 80%-3= 7.2 ± 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 ( P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions ( P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation ( P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.
Benign Granular Cell Tumor of the Vulva: First Report of Multiple Cases in a Family
Authors: Kardhashi Anila , Deliso Maria Assunta , Renna Alessandra , Trojano Giuseppe , Zito Francesco Alfredo , Trojano Vito
Published: April 2012

Granular cell tumors (GCTs) are uncommon soft tissue tumors of neural derivation, as supported by immunohistochemical and ultrastructural evidence. Vulvar involvement has been reported in 7–16%. This paper presents the cases of a 60-year-old woman and her 32-year-old niece with a strong family history of cancer, both presenting with an enlarging mass on their left labia majora. The lesions were treated by simple surgical excision. Histopathological examination revealed a benign vulvar GCT in both lesions. This is the first reported case of GCT of the vulva in the same family. The possible familial component of GCT needs further investigation. A systematic review of the literature on vulvar GCTs is carried out, the most complete one to date. This review unexpectedly reveals that there have been more than 130 cases of GCT of the vulva reported to date, only 7 of which were malignant. Since 5–25% of patients have multiple lesions, before planning treatment, clinicians should exclude multicentric lesions. After surgical treatment, if there is any evidence of tumor in the surgical margin, wider local excision should be performed. Regular follow-up is important for diagnosing a possible recurrence or a new lesion.
Association of Nerve Growth Factor and Vascular Endothelial Growth Factor A with Psychometric Measurements of Opiate Dependence: Results of a Pilot Study in Patients Participating in a Structured Diamorphine Maintenance Program
Authors: Heberlein Annemarie , Dürsteler-MacFarland Kenneth M. , Frieling Helge , Gröschl Michael , Lenz Bernd , Bönsch Dominikus , Kornhuber Johannes , Wiesbeck Gerhard A. , Bleich Stefan , Hillemacher Thomas
Published: April 2012

Preclinical study results suggest that neurotrophic peptides like nerve growth factor (NGF) and vascular endothelial growth factor A (VEGF-A) may be associated with symptoms of addictive behavior like withdrawal symptoms and rewarding effects. We investigated alterations in NGF and VEGF-A serum levels in opiate-dependent patients (25 male patients), who received diamorphine (DAM, heroin) treatment within a structured opiate maintenance program, and compared the results with the NGF and VEGF-A serum levels of healthy controls (23 male controls). NGF and VEGF-A serum levels were assessed before and after DAM administration twice a day (in the morning (16 h after last application – t1) and in the afternoon (7 h after last application – t3)) in order to detect a possible immediate or summative (in the afternoon) heroin effect on these two neuropeptides. Moreover, we investigated possible associations between the serum levels of these neurotrophic growth factors and psychometric dimensions of addictive behavior, e.g. craving, withdrawal, depression. Whereas there was no direct effect of DAM application on the serum levels of both neurotrophic growth factors neither in the morning nor in the afternoon, the NGF serum levels of the patient group were found to be significantly increased at all four time points of investigation compared with the healthy controls. In contrast, VEGF-A serum levels did not differ significantly in the patient and control groups. We found a significant positive association between the NGF serum levels and several items of the short opiate withdrawal scale as well as a negative association between self-reported mood (measured by visual analogue scale) and mood before heroin application (in the morning as in the afternoon). Moreover, we found a significant positive association between the NGF serum levels (t1 and t3) and the self-reported craving for methadone. In contrast, we found a negative association between the VEGF-A serum levels and avoidance, anxiety, suicide intentions of the SCL-90 as well as a positive association between the VEGF-A serum levels and the subscales of the heroin craving questionnaire measuring the rewarding effects of heroin. In conclusion, the results of this pilot study show that there might be an association between symptoms of opiate dependence and withdrawal and serum levels of VEGF-A and NGF.
Antiulcer Activity of Methanol Extract of Melastoma malabathricum Leaves in Rats
Authors: Zabidi Z. , Wan Zainulddin W.N. , Mamat S.S. , Shamsahal Din S. , Kamisan F.H. , Yahya F. , Ismail N.A. , Rodzi R. , Hassan H. , Mohtarrudin N. , Somchit M.N. , Zakaria Z.A.
Published: April 2012

Objective: To determine the potential antiulcer activity of methanol extract of Melastoma malabathricum leaves (MEMM) using various established rat models. Materials and Methods: Ten groups of rats were used and orally administered 10% DMSO (negative control), 100 mg/kg ranitidine (positive control) or MEMM (50, 250 and 500 mg/kg) followed by gastric ulcer induction either using ethanol or indomethacin. The stomachs were collected and subjected to macroscopic and microscopic analyses. Results: MEMM exhibited significant (p < 0.05) antiulcer activity in the ethanol, but not in the indomethacin-induced gastric ulcer model. The percentage of antiulcer activity for 50–500 mg/kg MEMM ranged between 3 and 75%, respectively. The gross observations were supported by histological findings. MEMM also aggravated the indomethacin-induced gastric ulcer, leading to an increase in ulcer area formation and ulcer score. Conclusion: The M. malabathricum leaves showed antiulcer activity, which could be attributed to their antioxidant and anti-inflammatory activities. This requires further in-depth studies.
Copy Number Changes on the X Chromosome in Women with and without Highly Skewed X-Chromosome Inactivation
Authors: Jobanputra V. , Levy B. , Kinney A. , Brown S. , Shirazi M. , Yu C. , Kline J. , Warburton D.
Published: April 2012

Aim: To test the hypothesis that microdeletions or microduplications below the resolution of a standard karyotype may be a significant cause of highly skewed X-inactivation (HSXI) in women without a cytogenetically detected X-chromosome anomaly. Methods: Cases were women with HSXI, defined as ≥85% of cells in a blood sample with the same active allele at the HUMARA locus. The skewing in controls ranged from 50 to <75%. We performed an SNP microarray analysis using the Affymetrix 6.0 platform for 45 cases and 45 controls. Results: Cases and controls did not differ in the frequency of X-chromosome copy number changes ≥100 kb or in the frequency of copy number changes that contained genes. However, one woman with HSXI >90% in blood and left and right buccal smears had a 5.5-Mb deletion in Xp22.2p22.1. This deletion could affect the viability of male conceptions and may have led to the dysmorphology found in female carriers. Conclusion: HSXI in a blood sample is rarely due to X-chromosome copy number changes detectable by microarray.
Evo-Devo of the Germline and Somatic Gonad in Nematodes
Authors: Pires-daSilva A. , Parihar M.
Published: April 2012

Due to recent progress in the development of genetic tools, nematodes have become excellent models to address the mechanistic basis of evolution of development. The gonad is one of the most variable structures in nematodes, reflecting the diverse modes of reproduction and lifestyle in this phylum. During larval development, the gonad primordium has a key role in organizing the neighboring tissues. Therefore, changes in the development of the gonad do not only influence the evolution of its morphology but also the overall body plan of the nematode. Here, we review recent progress on the evolution of development of the germline and somatic gonad in nematodes.
Blood Pressure Control Among US Veterans
Authors: Fletcher Ross D. , Amdur Richard L. , Kolodner Robert , McManus Chris , Jones Ronald , Faselis Charles , Kokkinos Peter , Singh Steven , Papademetriou Vasilios
Published: April 2012

Background—

Hypertension treatment and control remain low worldwide. Strategies to improve blood pressure control have been implemented in the United States and around the world for several years. This study was designed to assess improvement in blood pressure control over a 10-year period in a large cohort of patients in the Department of Veterans Affairs.

Methods and Results—

A cohort of 582 881 hypertensive patients and 260 924 normotensive individuals treated in 15 Department of Veterans Affairs medical centers between 2000 and 2010 were examined. Strategies used system-wide included blood pressure control as a performance measure, automatic notification to healthcare providers, electronic reminders, and a systematic revisit schedule. The main outcome measure was the percentage of hypertensive patients whose hypertension was controlled and the level of blood pressure each month. In the hypertensive cohort (mean age 62.9±13.4 years, 96.0% male), 52.3% of patients were white, 25.1% were black, and 21.1% were Hispanic. Blood pressure control rates improved from 45.7% in September 2000 to 76.3% in August 2010. Improvements were similar across ethnic, racial, age, and sex groups. Average systolic/diastolic blood pressure decreased from 142.6/77.1 mm Hg in 2000 to 131.2/74.8 mm Hg in 2010, a decrease of 11.3/2.3 mm Hg (
P
<0.0001 for both). Systolic and diastolic blood pressures were lower in summer than in winter, and this trend continued through 2010. On average, control rates increased by 3.0% per year and were 6.8% higher in summer than in winter.

Conclusions—

High rates of blood pressure control can be achieved in all age and ethnic groups and in both sexes.
Wind Rose Bias Correction
Authors: Applequist Scott
Published: April 2012

Wind rose summaries, which provide a basis for understanding and evaluating the climatological behavior of local wind, have a directional bias if a conventional method is used in their generation. Three techniques used to remove this bias are described and are compared for theoretical and observed wind distributions. All three techniques successfully remove the bias, with the simplest of the three performing as well as the more-complex techniques.
On the Relationship between Decadal Buoyancy Anomalies and Variability of the Atlantic Meridional Overturning Circulation
Authors: Buckley Martha W. , Ferreira David , Campin Jean-Michel , Marshall John , Tulloch Ross
Published: April 2012

Owing to the role of the Atlantic meridional overturning circulation (AMOC) in ocean heat transport, AMOC variability is thought to play a role in climate variability on a wide range of time scales. This paper focuses on the potential role of the AMOC in climate variability on decadal time scales. Coupled and ocean-only general circulation models run in idealized geometries are utilized to study the relationships between decadal AMOC and buoyancy variability and determine whether the AMOC plays an active role in setting sea surface temperature on decadal time scales. Decadal AMOC variability is related to changes in the buoyancy field along the western boundary according to the thermal wind relation. Buoyancy anomalies originate in the upper ocean of the subpolar gyre and travel westward as baroclinic Rossby waves. When the buoyancy anomalies strike the western boundary, they are advected southward by the deep western boundary current, leading to latitudinally coherent AMOC variability. The AMOC is observed to respond passively to decadal buoyancy anomalies: although variability of the AMOC leads to meridional ocean heat transport anomalies, these transports are not responsible for creating the buoyancy anomalies in the subpolar gyre that drive AMOC variability.
Simulated Atlantic Multidecadal Oscillation during the Holocene
Authors: Wei Wei , Lohmann Gerrit
Published: April 2012

The Atlantic multidecadal oscillation (AMO) and its possible change during the Holocene are examined in this study, using long-term simulations of the earth system model Community Earth System Models (COSMOS). A quasi-persistent ~55–80-yr cycle characterizing in the North Atlantic sea surface temperature is highly associated with the multidecadal variability of the Atlantic meridional overturning circulation (AMOC) during the Holocene. This mode can be found throughout the Holocene, indicating that the AMO is dominated by internal climate variability. Stronger-than-normal AMOC results in warmer-than-normal surface temperature spreading over almost the whole North Hemisphere, in particular the North Atlantic Ocean. During the warm phase of the AMO, more precipitation is detected in the North Atlantic low and high latitudes. It also generates a dipolar seesaw pattern in the sea ice anomaly. The results reveal that the influence of the AMO can be amplified by a more vigorous AMOC variability during the early Holocene in the presence of a remnant of the Laurentide Ice Sheet and when freshwater entered the North Atlantic Ocean. This conclusion could have potential application for the past AMO reconstruction and the future AMO estimation.
Scintillometer-Based Estimates of Sensible Heat Flux Using Lidar-Derived Surface Roughness
Authors: Geli Hatim M. E. , Neale Christopher M. U. , Watts Doyle , Osterberg John , De Bruin Henk A. R. , Kohsiek Wim , Pack Robert T. , Hipps Lawrence E.
Published: April 2012

The estimation of sensible heat flux, H, using large aperture scintillometer (LAS) under varying surface heterogeneity conditions was investigated. Surface roughness features characterized by variable topography and vegetation height were represented using data derived from the highly accurate light detection and range (lidar) techniques as well as from traditional vegetation survey and topographic map methods. The study was conducted at the Cibola National Wildlife Refuge, Southern California, over a riparian zone covered with natural vegetation dominated by tamarisk trees interspersed with bare soil in a region characterized by arid to semiarid climatic conditions. Estimates of H were obtained using different representations of surface roughness features derived from both traditional and lidar methods to estimate LAS beam height [z(u)] at each increment u along its path, vegetation height (hc), displacement height (d), and roughness length (z0) combined with the LAS weighing function, W(u), along the path. The effect of the LAS 3D footprint was examined to account for the contribution from the individual patches in the upwind direction, hence on the estimates of H. The results showed better agreement between LAS and Bowen ratio sensible heat fluxes when lidar-derived surface roughness was used, especially when considering the LAS 3D footprint effects. It was also found that, under certain conditions, the LAS path weighted hc and d obtained using the LAS weighting function W(u) is a good approximation of the 3D weighted footprint values.
Data Transformation and Uncertainty in Geostatistical Combination of Radar and Rain Gauges
Authors: Erdin Rebekka , Frei Christoph , Künsch Hans R.
Published: April 2012

Geostatistics provides a popular framework for deriving high-resolution quantitative precipitation estimates (QPE) by combining radar and rain gauge data. However, the skewed and heteroscedastic nature of precipitation is in contradiction to assumptions of classical geostatistics. This study examines the potential of trans-Gaussian kriging to overcome this contradiction. Combination experiments are undertaken with kriging with external drift (KED) using several settings of the Box–Cox transformation. Hourly precipitation data in Switzerland for the year 2008 serve as test bed to compare KED with and without transformation. The impact of transformation is examined with regard to compliance with model assumptions, accuracy of the point estimate, and reliability of the probabilistic estimate. Data transformation improves the compliance with model assumptions, but some level of contradiction remains in situations with many dry gauges. Very similar point estimates are found for KED with untransformed and appropriately transformed data. However, care is needed to avoid excessive transformation (close to log) because this can introduce a positive bias. Strong benefits from transformation are found for the probabilistic estimate, which is rendered positively skewed, sensitive to precipitation amount, and quantitatively more reliable. Without transformation, 44% of all precipitation observations larger than 5 mm h−1 are considered as extremely unlikely by the probabilistic estimate in the test application. Transformation reduces this rate to 4%. Although transformation cannot fully remedy the complications for geostatistics in radar–gauge combination, it seems a useful procedure if realistic and reliable estimation uncertainties are desired, such as for the stochastic simulation of QPE ensembles.
Eddy-Train Encounters with a Continental Boundary: A South Atlantic Case Study
Authors: Azevedo José L. L. , Nof Doron , Mata Mauricio M.
Published: April 2012

Satellite altimetry suggests that large anticyclonic eddies (rings) originating from the Agulhas Current retroflection occasionally make their way across the entire South Atlantic Ocean. What happens when these rings encounter a western boundary current? In this work, interactions between a “train” of nonlinear lens-like eddies and a Southern Hemisphere continental boundary are investigated analytically and numerically on a β plane. The train of eddies is modeled as a steady double-frontal zonal current with the same vorticity and transport as the eddies themselves. The continental boundary is represented by a vertical wall, which is purely meridional in one case and is tilted with respect to the north in another case. It is demonstrated analytically that the eddy–wall encounter produces an equatorward flow parallel to the continental wall, thus suggesting a weakening of the transport of the associated (poleward flowing) western boundary current upstream of the encounter zone and unchanged transport downstream. A large stationary eddy is established in the contact zone because its β-induced force is necessary to balance the other forces along the wall. The size of this eddy is directly proportional to the transport of the eddy train and the meridional tilt of the wall. These scenarios are in good agreement with results obtained numerically using an isopycnal Bleck and Boudra model.
Making Redistributive Direct Democracy Matter
Authors: Gibson Christopher
Published: April 2012

Existing sociological theories highlight five explanations of development, which focus on leftist political parties in state power, women’s office-holding, state capacity, social capital and resource mobilization, and state expenditure. Increasingly, however, the execution of development schemes by large democratic states of the global South relies on citizen participation in what I define as Redistributive Direct Democracy (RDD). RDD institutions devolve formal authorities and create political opportunities for participants to themselves allocate and claim development benefits. Within India’s approximately two million local governments, a permanent RDD institution called the gram sabha offers all participants the formal, constitutional authority to directly select recipients of state benefits such as public housing and latrines. Drawing on fixed-effects, multivariate OLS analyses of data collected in a stratified random sample of 72 Indian local governments with active gram sabhas, I argue for a sixth, complementary explanation of development in democracies of the global South: women’s participation in RDD. My analysis demonstrates strongly positive and highly significant effects of women’s gram sabha participation on local development and a contrasting absence of support for longstanding explanations. These findings suggest that women’s participation in RDD can make these new and popular, but poorly understood institutions matter for development outcomes.
Accounting for the Effects of Identity on Political Behavior
Authors: Chernyha Lachen T. , Burg Steven L.
Published: April 2012

This article examines the determinants of identification within the autonomous communities (ACs) of Spain and explores whether “activated identities” guide behavior. The authors test this hypothesized effect empirically and demonstrate that regional and especially (non-Spanish) national activated identity affect preferences for exclusionary policies and for greater autonomy or independence for the AC. Both preferences and activated identities increase the likelihood of voting for regional, rather than statewide, political parties. The authors argue that the strength of attachment to identity (i.e., to the AC to or Spain) and the effect of identities on preferences constitute the mechanisms that link identity to behaviors. Thus, the authors contribute to, and help to clarify, both the theoretical and empirical literatures focused on the relationship between identity and behaviors.
Having Your Day in Court
Authors: Doherty Brian , Hayes Graeme
Published: April 2012

Investigating the recent direct action campaigns against genetically modified crops in France and the United Kingdom, the authors set out to understand how contrasting judicial systems and cultures affect the way that activists choose to commit ostensibly illegal actions and how they negotiate the trade-offs between effectiveness and public accountability. The authors find evidence that prosecution outcomes across different judicial systems are consistent and relatively predictable and consequently argue that the concept of a “judicial opportunity structure” is useful for developing scholars’ understanding of social movement trajectories. The authors also find that these differential judicial opportunities cannot adequately account for the tactical choices made by activists with respect to the staging of covert or overt direct action; rather, explanations of tactical choice are better accounted for by movement ideas, cultures, and traditions.
The Assessment of Reliability Under Range Restriction
Authors: Fife Dustin A. , Mendoza Jorge L. , Terry Robert
Published: April 2012

Though much research and attention has been directed at assessing the correlation coefficient under range restriction, the assessment of reliability under range restriction has been largely ignored. This article uses item response theory to simulate dichotomous item-level data to assess the robustness of KR-20 (α), ω, and test–retest under varying selection ratios. These estimators, both corrected and uncorrected for range restriction, were compared in terms of both bias and precision. Test–retest reliability was usually the best estimator of reliability across a variety of conditions. Only under indirect range restriction did KR-20 and ω performed well. All estimators suffered imprecision as a function of range restriction, above and beyond the reduction in sample size. Based on the results, a set of recommendations are proposed.
Feasibility of recruiting peer educators for an online social networking-based health intervention
Authors: Young Sean D , Harrell Lauren , Jaganath Devan , Cohen Adam Carl , Shoptaw Steve
Published: April 2012

Objective:

This study aims to determine the feasibility of recruiting peer leaders to deliver a community-based health intervention using social media.

Method:

We recruited 16 African American and Latino men who have sex with men (MSM) as peer leaders for either an human immunodeficiency virus (HIV) prevention or general health intervention using social media. Inclusion criteria required that peer leaders were African American or Latino MSM health communication experts experienced using social media. To receive certification, peer leaders attended three training sessions on using social media for public health. Questionnaires asking about health knowledge and comfort using social media to discuss health-related topics were provided at baseline and post-training to ensure that peer leaders were qualified post-training. Repeated measures analysis of variance (ANOVA) models and χ2 tests tested for differences in peer leader knowledge and comfort using social media pre- and post-training.

Results:

After training, peer leaders were significantly more comfortable using social media to discuss sexual positions. There were no significant differences pre- and post-training on other comfort or knowledge measures as, at baseline, almost all peer leaders were already comfortable using social media.

Conclusion:

Results suggest that peer leaders can be recruited who are qualified to conduct health interventions without needing additional training. The discussed training plan can further ensure that any unqualified peer leaders will be prepared after training. To our knowledge, this is the first study to suggest that peer leaders can be recruited as peer health educators to communicate using social media.