bluuebunny/crossref_metadata_2025 huggingface dataset:
ON d+id DENSITY WAVE AND SUPERCONDUCTING ORDERINGS IN HOLE-DOPED CUPRATES
Authors: GOSWAMI PARTHA , GAHLOT AJAY PRATAP SINGH , SINGH PANKAJ
Published: May 2013

The d+id-density wave (chiral DDW) order, at the anti-ferromagnetic wave vector Q = (π, π), is assumed to represent the pseudo-gap (PG) state of a hole-doped cuprate superconductor. The pairing interaction U(k, k′) required for d+id ordering comprises of (Ux2-y2(k, k′), Uxy(k, k′)), where [Formula: see text] and [Formula: see text] with U1 > U2. The d-wave superconductivity (DSC), driven by an assumed attractive interaction of the form [Formula: see text] where V1 is a model parameter, is discussed within the mean-field framework together with the d+id ordering. The single-particle excitation spectrum in the CDDW + DSC state is characterized by the Bogoluibov quasi-particle bands — a characteristic feature of SC state. The coupled gap equations are solved self-consistently together with the equation to determine the chemical potential (μ). With the pinning of the van Hove-singularities close to μ, one is able to calculate the thermodynamic and transport properties of the under-doped cuprates in a consistent manner. The electron specific heat displays non-Fermi liquid feature in the CDDW state. The CDDW and DSC are found to represent two competing orders as the former brings about a depletion of the spectral weight (and Raman response function density) available for pairing in the anti-nodal region of momentum space. It is also shown that the depletion of the spectral weight below Tc at energies larger than the gap amplitude occurs. This is an indication of the strong-coupling superconductivity in cuprates. The calculation of the ratio of the quasi-particle thermal conductivity αxx and temperature in the superconducting phase is found to be constant in the limit of near-zero quasi-particle scattering rate.
MODIFIED BCS GAP EQUATION FOR JAHN–TELLER DISTORTED HIGH TEMPERATURE SUPERCONDUCTORS
Authors: RAJ B. K. , PRADHAN B. , ROUT G. C.
Published: May 2013

In this communication we report the interplay of the normal electron-phonon (EP) interaction, dynamic Jahn–Teller (DJT) distortion and superconductivity in high temperature superconductors in presence of a static lattice strain. This model consists of a degenerate two orbital band separated by Jahn–Teller (JT) energy modified by the DJT interaction in the conduction band. The superconductivity is assumed to be s-wave type present in the same band. The interaction Hamiltonian is solved by Green's function method and a modified BCS gap equation is obtained with a modified conduction band energy [Formula: see text] and modified BCS order parameter [Formula: see text] with α = 1, 2 designating the two orbitals. This interplay displays some new interesting results which are different from the effect of the static lattice strain on superconducting (SC) order parameter. The interplay is studied by varying the normal EP coupling, the DJT coupling, the SC coupling, the phonon vibration frequency, the phonon wave vector and other model parameters of the system.
ENTIRE SOLUTIONS FOR LOTKA–VOLTERRA COMPETITION-DIFFUSION MODEL
Authors: WANG XIAOHUAN , LV GUANGYING
Published: May 2013

This paper is concerned with the existence of entire solutions of Lotka–Volterra competition-diffusion model. Using the comparing argument and sub-super solutions method, we obtain the existence of entire solutions which behave as two wave fronts coming from the both sides of x-axis, where an entire solution is meant by a classical solution defined for all space and time variables.
Molecular Mechanisms of RNA Interference
Authors: Wilson Ross C. , Doudna Jennifer A.
Published: May 2013

Small RNA molecules regulate eukaryotic gene expression during development and in response to stresses including viral infection. Specialized ribonucleases and RNA-binding proteins govern the production and action of small regulatory RNAs. After initial processing in the nucleus by Drosha, precursor microRNAs (pre-miRNAs) are transported to the cytoplasm, where Dicer cleavage generates mature microRNAs (miRNAs) and short interfering RNAs (siRNAs). These double-stranded products assemble with Argonaute proteins such that one strand is preferentially selected and used to guide sequence-specific silencing of complementary target mRNAs by endonucleolytic cleavage or translational repression. Molecular structures of Dicer and Argonaute proteins, and of RNA-bound complexes, have offered exciting insights into the mechanisms operating at the heart of RNA-silencing pathways.
Opposing effects of podocin on the gating of podocyte TRPC6 channels evoked by membrane stretch or diacylglycerol
Authors: Anderson Marc , Kim Eun Young , Hagmann Henning , Benzing Thomas , Dryer Stuart E.
Published: May 2013

Gain-of-function mutations in the transient receptor potential (TRP) cation channel subfamily C member 6 ( TRPC6) gene and mutations in the NPHS2 gene encoding podocin result in nephrotic syndromes. The purpose of this study was to determine the functional significance of biochemical interactions between these proteins. We observed that gating of TRPC6 channels in podocytes is markedly mechanosensitive and can be activated by hyposmotic stretch or indentation of the plasma membrane. Stretch activation of cationic currents was blocked by small interfering RNA knockdown of TRPC6, as well as by SKF-96365 or micromolar La3+. Stretch activation of podocyte TRPC6 persisted in the presence of inhibitors of phospholipase C (U-73122) and phospholipase A2 (ONO-RS-082). Robust stretch responses also persisted when recording electrodes contained guanosine 5′- O-(2-thiodiphosphate) at concentrations that completely suppressed responses to ANG II. Stretch responses were enhanced by cytochalasin D but were abolished by the peptide GsMTx4, suggesting that forces are transmitted to the channels through the plasma membrane. Podocin and TRPC6 interact at their respective COOH termini. Knockdown of podocin markedly increased stretch-evoked activation of TRPC6 but nearly abolished TRPC6 activation evoked by a diacylglycerol analog. These data suggest that podocin acts as a switch to determine the preferred mode of TRPC6 activation. They also suggest that podocin deficiencies will result in Ca2+ overload in foot processes, as with gain-of-function mutations in the TRPC6 gene. Finally, they suggest that mechanical activation of TRP family channels and the preferred mode of TRP channel activation may depend on whether members of the stomatin/prohibitin family of hairpin loop proteins are present.
Role for intestinal CYP2E1 in alcohol-induced circadian gene-mediated intestinal hyperpermeability
Authors: Forsyth Christopher B. , Voigt Robin M. , Shaikh Maliha , Tang Yueming , Cederbaum Arthur I. , Turek Fred W. , Keshavarzian Ali
Published: May 2013

We have shown that alcohol increases Caco-2 intestinal epithelial cell monolayer permeability in vitro by inducing the expression of redox-sensitive circadian clock proteins CLOCK and PER2 and that these proteins are necessary for alcohol-induced hyperpermeability. We hypothesized that alcohol metabolism by intestinal Cytochrome P450 isoform 2E1 (CYP2E1) could alter circadian gene expression ( Clock and Per2), resulting in alcohol-induced hyperpermeability. In vitro Caco-2 intestinal epithelial cells were exposed to alcohol, and CYP2E1 protein, activity, and mRNA were measured. CYP2E1 expression was knocked down via siRNA and alcohol-induced hyperpermeability, and CLOCK and PER2 protein expression were measured. Caco-2 cells were also treated with alcohol or H2O2 with or without N-acetylcysteine (NAC) anti-oxidant, and CLOCK and PER2 proteins were measured at 4 or 2 h. In vivo Cyp2e1 protein and mRNA were also measured in colon tissue from alcohol-fed mice. Alcohol increased CYP2E1 protein by 93% and enzyme activity by 69% in intestinal cells in vitro. Alcohol feeding also increased mouse colonic Cyp2e1 protein by 73%. mRNA levels of Cyp2e1 were not changed by alcohol in vitro or in mouse intestine. siRNA knockdown of CYP2E1 in Caco-2 cells prevented alcohol-induced hyperpermeability and induction of CLOCK and PER2 proteins. Alcohol-induced and H2O2-induced increases in intestinal cell CLOCK and PER2 were significantly inhibited by treatment with NAC. We concluded that our data support a novel role for intestinal CYP2E1 in alcohol-induced intestinal hyperpermeability via a mechanism involving CYP2E1-dependent induction of oxidative stress and upregulation of circadian clock proteins CLOCK and PER2.
Repeated variate stress in male rats induces increased voiding frequency, somatic sensitivity, and urinary bladder nerve growth factor expression
Authors: Merrill Liana , Malley Susan , Vizzard Margaret A.
Published: May 2013

Stress exacerbates symptoms of functional lower urinary tract disorders including interstitial cystitis (IC)/bladder pain syndrome (BPS) and overactive bladder (OAB) in humans, but mechanisms contributing to symptom worsening are unknown. These studies address stress-induced changes in the structure and function of the micturition reflex using an animal model of stress in male rats. Rats were exposed to 7 days of repeated variate stress (RVS). Target organ (urinary bladder, thymus, adrenal gland) tissues were collected and weighed following RVS. Evans blue (EB) concentration and histamine, myeloperoxidase (MPO), nerve growth factor (NGF), brain-derived neurotropic factor (BDNF), and CXCL12 protein content (ELISA) were measured in the urinary bladder, and somatic sensitivity of the hindpaw and pelvic regions was determined following RVS. Bladder function was evaluated using continuous, open outlet intravesical infusion of saline in conscious rats. Increases in body weight gain were significantly ( P ≤ 0.01) attenuated by day 5 of RVS, and adrenal weight was significantly ( P ≤ 0.05) increased. Histamine, MPO, NGF, and CXCL12 protein expression was significantly ( P ≤ 0.01) increased in the urinary bladder after RVS. Somatic sensitivity of the hindpaw and pelvic regions was significantly ( P ≤ 0.01) increased at all monofilament forces tested (0.1–4 g) after RVS. Intercontraction interval, infused volume, and void volume were significantly ( P ≤ 0.01) decreased after RVS. These studies demonstrate increased voiding frequency, histamine, MPO, NGF, and CXCL12 bladder content and somatic sensitivity after RVS suggesting an inflammatory component to stress-induced changes in bladder function and somatic sensitivity.
Chronic elevation of IL-1β induces diuresis via a cyclooxygenase 2-mediated mechanism
Authors: Boesen E. I.
Published: May 2013

Chronic renal inflammation is an increasingly recognized phenomenon in multiple disease states, but the impact of specific cytokines on renal function is unclear. Previously, we found that 14-day interleukin-1β (IL-1β) infusion increased urine flow in mice. To determine the mechanism by which this occurs, the current study tested the possible involvement of three classical prodiuretic pathways. Chronic IL-1β infusion significantly increased urine flow (6.5 ± 1 ml/day at day 14 vs. 2.3 ± 0.3 ml/day in vehicle group; P < 0.05) and expression of cyclooxygenase (COX)-2, all three nitric oxide synthase (NOS) isoforms, and endothelin (ET)-1 in the kidney ( P < 0.05 in all cases). Urinary prostaglandin E metabolite (PGEM) excretion was also significantly increased at day 14 of IL-1β infusion (1.21 ± 0.26 vs. 0.29 ± 0.06 ng/day in vehicle-infused mice; P = 0.001). The selective COX-2 inhibitor celecoxib markedly attenuated urinary PGEM excretion and abolished the diuretic response to chronic IL-1β infusion. In contrast, deletion of NOS3, or inhibition of NOS1 with l-VNIO, did not blunt the diuretic effect of IL-1β, nor did pharmacological blockade of endothelin ETAand ETBreceptors with A-182086. Consistent with a primary effect on water transport, IL-1β infusion markedly reduced inner medullary aquaporin-2 expression ( P < 0.05) and did not alter urinary Na+or K+excretion. These data indicate a critical role for COX-2 in mediating the effects of chronic IL-1β elevation on the kidney.
Scavengers of reactive oxygen species, paracalcitol, RhoA, and Rac-1 inhibitors and tacrolimus inhibit angiotensin II-induced actions on glomerular permeability
Authors: Axelsson Josefin , Rippe Anna , Sverrisson Kristinn , Rippe Bengt
Published: May 2013

Systemic infusions of ANG II rapidly induce large, dynamic increases in the permeability of the glomerular filtration barrier (GFB) in rats. After binding to its receptor(s), ANG II generates reactive oxygen species (ROS) and produces Ca2+ influx into cells, leading to activation of a plethora of signaling cascades, including, e.g., calcineurin and small GTPases, such as Rac-1 and RhoA. In the present study we sought to interact with some of these cascades to test potential novel antiproteinuric agents. In anesthetized Wistar rats, the left urether was cannulated for urine collection, and blood access was achieved. Rats were infused with ANG II (16 ng·kg−1·min−1) alone, or together with the ROS scavengers tempol or dimethylthiourea (DMTU) or the D-vitamin analog paracalcitol, the RhoA-kinase inhibitor Y-27632, the Rac-1 inhibitor NSC-23766, or the calcineurin inhibitor tacrolimus. FITC-Ficoll-70/400 (mol.radius 10–80 Å) and 51Cr-EDTA were infused throughout the experiment. Plasma and urine samples were taken during baseline and at 5 and 15 min after the start of the infusions and analyzed by high-performance size-exclusion chromatography for determination of glomerular sieving coefficients (θ) for Ficoll10–80Å. ANG II infusion into rats caused marked increases in glomerular permeability to large Ficoll molecules (Ficoll50–80Å), which were abrogated by the ROS scavenger tempol and partly by DMTU. Paracalcitol, RhoA, and Rac-1 inhibition, and, to some extent tacrolimus, but not prostacyclin, could also inhibit the glomerular permeability actions of ANG II. Our data suggest that cellular ROS generation and active Ca2+ signaling are involved in ANG II-induced increases in glomerular permeability.
NF-κB activation mediates crystal translocation and interstitial inflammation in adenine overload nephropathy
Authors: Okabe Cristiene , Borges Raquel Lerner , de Almeida Danilo Candido , Fanelli Camilla , Barlette Grasiela Pedreira , Machado Flavia Gomes , Arias Simone Costa Alarcon , Malheiros Denise Maria Avancini Costa , Camara Niels Olsen Saraiva , Zatz Roberto , Fujihara Clarice Kazue
Published: May 2013

Adenine overload promotes intratubular crystal precipitation and interstitial nephritis. We showed recently that these abnormalities are strongly attenuated in mice knockout for Toll-like receptors-2, -4, MyD88, ASC, or caspase-1. We now investigated whether NF-κB activation also plays a pathogenic role in this model. Adult male Munich-Wistar rats were distributed among three groups: C ( n = 17), receiving standard chow; ADE ( n = 17), given adenine in the chow at 0.7% for 1 wk and 0.5% for 2 wk; and ADE + pyrrolidine dithiocarbamate (PDTC; n = 14), receiving adenine as above and the NF-κB inhibitor PDTC (120 mg·kg−1·day−1 in the drinking water). After 3 wk, widespread crystal deposition was seen in tubular lumina and in the renal interstitium, along with granuloma formation, collagen accumulation, intense tubulointerstitial proliferation, and increased interstitial expression of inflammatory mediators. Part of the crystals were segregated from tubular lumina by a newly formed cell layer and, at more advanced stages, appeared to be extruded to the interstitium. p65 nuclear translocation and IKK-α increased abundance indicated activation of the NF-κB system. PDTC treatment prevented p65 migration and normalized IKK-α, limited crystal shift to the interstitium, and strongly attenuated interstitial fibrosis/inflammation. These findings indicate that the complex inflammatory phenomena associated with this model depend, at least in part, on NF-κB activation, and suggest that the NF-κB system may become a therapeutic target in the treatment of chronic kidney disease.
Zyxin regulates migration of renal epithelial cells through activation of hepatocyte nuclear factor-1β
Authors: Choi Yun-Hee , McNally Brian T. , Igarashi Peter
Published: May 2013

Hepatocyte nuclear factor-1β (HNF-1β) is an epithelial tissue-specific transcription factor that regulates gene expression in the kidney, liver, pancreas, intestine, and other organs. Mutations of HNF-1β in humans produce renal cysts and congenital kidney anomalies. Here, we identify the LIM-domain protein zyxin as a novel binding partner of HNF-1β in renal epithelial cells. Zyxin shuttles to the nucleus where it colocalizes with HNF-1β. Immunoprecipitation of zyxin in leptomycin B-treated cells results in coprecipitation of HNF-1β. The protein interaction requires the second LIM domain of zyxin and two distinct domains of HNF-1β. Overexpression of zyxin stimulates the transcriptional activity of HNF-1β, whereas small interfering RNA silencing of zyxin inhibits HNF-1β-dependent transcription. Epidermal growth factor (EGF) induces translocation of zyxin into the nucleus and stimulates HNF-1β-dependent promoter activity. The EGF-mediated nuclear translocation of zyxin requires activation of Akt. Expression of dominant-negative mutant HNF-1β, knockdown of zyxin, or inhibition of Akt inhibits EGF-stimulated cell migration. These findings reveal a novel pathway by which extracellular signals are transmitted to the nucleus to regulate the activity of a transcription factor that is essential for renal epithelial differentiation.
Analysis of stimulus-related activity in rat auditory cortex using complex spectral coefficients
Authors: Krause Bryan M. , Banks Matthew I.
Published: May 2013

The neural mechanisms of sensory responses recorded from the scalp or cortical surface remain controversial. Evoked vs. induced response components (i.e., changes in mean vs. variance) are associated with bottom-up vs. top-down processing, but trial-by-trial response variability can confound this interpretation. Phase reset of ongoing oscillations has also been postulated to contribute to sensory responses. In this article, we present evidence that responses under passive listening conditions are dominated by variable evoked response components. We measured the mean, variance, and phase of complex time-frequency coefficients of epidurally recorded responses to acoustic stimuli in rats. During the stimulus, changes in mean, variance, and phase tended to co-occur. After the stimulus, there was a small, low-frequency offset response in the mean and modest, prolonged desynchronization in the alpha band. Simulations showed that trial-by-trial variability in the mean can account for most of the variance and phase changes observed during the stimulus. This variability was state dependent, with smallest variability during periods of greatest arousal. Our data suggest that cortical responses to auditory stimuli reflect variable inputs to the cortical network. These analyses suggest that caution should be exercised when interpreting variance and phase changes in terms of top-down cortical processing.
Amygdala inputs drive feedforward inhibition in the medial prefrontal cortex
Authors: Dilgen Jonathan , Tejeda Hugo A. , O'Donnell Patricio
Published: May 2013

Although interactions between the amygdala and prefrontal cortex (PFC) are critical for emotional guidance of behavior, the manner in which amygdala affects PFC function is not clear. Whereas basolateral amygdala (BLA) output neurons exhibit many characteristics associated with excitatory neurotransmission, BLA stimulation typically inhibits PFC cell firing. This apparent discrepancy could be explained if local PFC inhibitory interneurons were activated by BLA inputs. Here, we used in vivo juxtacellular and intracellular recordings in anesthetized rats to investigate whether BLA inputs evoke feedforward inhibition in the PFC. Juxtacellular recordings revealed that BLA stimulation evoked action potentials in PFC interneurons and silenced most pyramidal neurons. Intracellular recordings from PFC pyramidal neurons showed depolarizing postsynaptic potentials, with multiple components evoked by BLA stimulation. These responses exhibited a relatively negative reversal potential (Erev), suggesting the contribution of a chloride component. Intracellular administration or pressure ejection of the GABA-A antagonist picrotoxin resulted in action-potential firing during the BLA-evoked response, which had a more depolarized Erev. These results suggest that BLA stimulation engages a powerful inhibitory mechanism within the PFC mediated by local circuit interneurons.
Zingerone enhances glutamatergic spontaneous excitatory transmission by activating TRPA1 but not TRPV1 channels in the adult rat substantia gelatinosa
Authors: Yue Hai-Yuan , Jiang Chang-Yu , Fujita Tsugumi , Kumamoto Eiichi
Published: May 2013

Transient receptor potential (TRP) channels are thought to play a role in regulating nociceptive transmission to spinal substantia gelatinosa (SG) neurons. It remains to be unveiled whether the TRP channels in the central nervous system are different in property from those involved in receiving nociceptive stimuli in the peripheral nervous system. We examined the effect of the vanilloid compound zingerone, which activates TRPV1 channels in the cell body of a primary afferent neuron, on glutamatergic excitatory transmission in the SG neurons of adult rat spinal cord slices by using the whole cell patch-clamp technique. Bath-applied zingerone reversibly and concentration-dependently increased spontaneous excitatory postsynaptic current (EPSC) frequency. This effect was accompanied by an inward current at −70 mV that was resistant to glutamate receptor antagonists. These zingerone effects were repeated and persisted in Na+-channel blocker tetrodotoxin-, La3+-, or IP3-induced Ca2+-release inhibitor 2-aminoethoxydiphenyl borate-containing or Ca2+-free Krebs solution. Zingerone activity was resistant to the selective TRPV1 antagonist capsazepine but sensitive to the nonselective TRP antagonist ruthenium red, the TRPA1 antagonist HC-030031, and the Ca2+-induced Ca2+-release inhibitor dantrolene. TRPA1 agonist allyl isothiocyanate but not capsaicin inhibited the facilitatory effect of zingerone. On the other hand, zingerone reduced monosynaptically evoked EPSC amplitudes, as did TRPA1 agonists. Like allyl isothiocyanate, zingerone enhanced GABAergic spontaneous inhibitory transmission in a manner sensitive to tetrodotoxin. We conclude that zingerone presynaptically facilitates spontaneous excitatory transmission, probably through Ca2+-induced Ca2+-release mechanisms, and produces a membrane depolarization in SG neurons by activating TRPA1 but not TRPV1 channels.
Behavioral and modeling studies of sound localization in cats: effects of stimulus level and duration
Authors: Gai Yan , Ruhland Janet L. , Yin Tom C. T. , Tollin Daniel J.
Published: May 2013

Sound localization accuracy in elevation can be affected by sound spectrum alteration. Correspondingly, any stimulus manipulation that causes a change in the peripheral representation of the spectrum may degrade localization ability in elevation. The present study examined the influence of sound duration and level on localization performance in cats with the head unrestrained. Two cats were trained using operant conditioning to indicate the apparent location of a sound via gaze shift, which was measured with a search-coil technique. Overall, neither sound level nor duration had a notable effect on localization accuracy in azimuth, except at near-threshold levels. In contrast, localization accuracy in elevation improved as sound duration increased, and sound level also had a large effect on localization in elevation. For short-duration noise, the performance peaked at intermediate levels and deteriorated at low and high levels; for long-duration noise, this “negative level effect” at high levels was not observed. Simulations based on an auditory nerve model were used to explain the above observations and to test several hypotheses. Our results indicated that neither the flatness of sound spectrum (before the sound reaches the inner ear) nor the peripheral adaptation influences spectral coding at the periphery for localization in elevation, whereas neural computation that relies on “multiple looks” of the spectral analysis is critical in explaining the effect of sound duration, but not level. The release of negative level effect observed for long-duration sound could not be explained at the periphery and, therefore, is likely a result of processing at higher centers.
Input-output organization of inhibitory neurons in the interstitial nucleus of Cajal projecting to the contralateral trochlear and oculomotor nucleus
Authors: Sugiuchi Y. , Takahashi M. , Shinoda Y.
Published: May 2013

Neurons in the interstitial nucleus of Cajal (INC) that are known to be involved in eye and head movements are excitatory. We investigated the input-output organization of inhibitory INC neurons involved in controlling vertical saccades. Intracellular recordings were made in INC neurons activated antidromically by stimulation of the contralateral trochlear or oculomotor nucleus, and their synaptic input properties from the superior colliculi (SCs) and the contralateral INC were analyzed in anesthetized cats. Many INC neurons projected to the contralateral trochlear nucleus, Forel's field H, INC, and oculomotor nucleus, and mainly received monosynaptic excitation followed by disynaptic inhibition from the ipsi- and contralateral SCs. After sectioning the commissural connections between the SCs, these neurons received monosynaptic excitation from the ipsilateral medial SC and disynaptic inhibition via the INC from the contralateral lateral SC. Another group of INC neurons were antidromically activated from the contralateral oculomotor nucleus, INC and Forel's field H, but not from the trochlear nucleus, and received monosynaptic excitation from the ipsilateral lateral SC and disynaptic inhibition from the contralateral medial SC. The former group was considered to inhibit contralateral trochlear and inferior rectus motoneurons in upward saccades, whereas the latter was considered to inhibit contralateral superior rectus and inferior oblique motoneurons in downward saccades. The mutual inhibition existed between these two groups of INC neurons for upward saccades on one side and downward saccades on the other. This pattern of input-output organization of inhibitory INC neurons suggests that the basic neural circuits for horizontal and vertical saccades are similar.
Developmental changes in GABAergic neurotransmission to presympathetic and cardiac parasympathetic neurons in the brainstem
Authors: Dergacheva Olga , Boychuk Carie R. , Mendelowitz David
Published: May 2013

Cardiovascular function is regulated by a dynamic balance composed of sympathetic and parasympathetic activity. Sympathoexcitatory presympathetic neurons (PSNs) in the rostral ventrolateral medulla project directly to cardiac and vasomotor sympathetic preganglionic neurons in the spinal cord. In proximity to the PSNs in the medulla, there are preganglionic cardiac vagal neurons (CVNs) within the nucleus ambiguus, which are critical for parasympathetic control of heart rate. Both CVNs and PSNs receive GABAergic synaptic inputs that change with challenges such as hypoxia and hypercapnia (H/H). Autonomic control of cardiovascular function undergoes significant changes during early postnatal development; however, little is known regarding postnatal maturation of GABAergic neurotransmission to these neurons. In this study, we compared changes in GABAergic inhibitory postsynaptic currents (IPSCs) in CVNs and PSNs under control conditions and during H/H in postnatal day 2–5 (P5), 16–20 (P20), and 27–30 (P30) rats using an in vitro brainstem slice preparation. There was a significant enhancement in GABAergic neurotransmission to both CVNs and PSNs at age P20 compared with P5 and P30, with a more pronounced increase in PSNs. H/H did not significantly alter this enhanced GABAergic neurotransmission to PSNs in P20 animals. However, the frequency of GABAergic IPSCs in PSNs was reduced by H/H in P5 and P30 animals. In CVNs, H/H elicited an inhibition of GABAergic neurotransmission in all ages studied, with the most pronounced inhibition occurring at P20. In conclusion, there are critical development periods at which significant rearrangement occurs in the central regulation of cardiovascular function.
Pentoxifylline Loaded Floating Microballoons: Design, Development and Characterization
Authors: Malik Prashant , Nagaich Upendra , Malik Raj Kaur , Gulati Neha
Published: May 2013

The floating microballoons have been utilized to obtain prolonged and uniform release in the stomach. The objective of the present study involves design, development, and characterization of pentoxifylline loaded floating microballoons to prolong their gastric residence time. Pentoxifylline (trisubstituted xanthine derivative) loaded microballoons were prepared by the solvent evaporation technique using different concentrations of polymers like HPMC K4M and ethyl cellulose (EC) in ethyl alcohol and dichloromethane organic solvent system. Microballoons were characterized for their particle size, surface morphology, production yield, loading efficiency, buoyancy percentage, and in vitro drug release studies. From the characterization it was observed that increases in amount of polymers (HPMC K4M and EC) led to increased particle size, loading efficiency, and buoyancy percentage, and retarded drug release. The particle size, particle yield, loading efficiency, buoyancy percentage and in vitro drug release for optimized formulation (F3) were found to be 104.0±2.87 µm, 80.89±2.24%, 77.85±0.61%, 77.52±2.04%, and 82.21±1.29%, respectively. The data was fitted to different kinetic models to illustrate its anomalous (non-Fickian) diffusion. The in vitro result showed that formulations comprised of varying concentrations of ethyl cellulose in higher proportion exhibited much retarded drug release as compared to formulations comprised of higher proportion of varying concentrations of HPMC K4M.
Cortex Effect on Vacuum Drying Process of Porous Medium
Authors: Zhang Zhijun , Zhang Shiwei , Su Tianyi , Zhao Shuangshuang
Published: May 2013

Corns, fruits, and vegetables are usually used as porous medium in drying process. But in fact, it must be considered as the cortex effect on mass transfer because the mass transfer of cortex is very difficult than inner medium. Based on the theory of heat and mass transfer, a coupled model for the porous medium vacuum drying process with cortex effect is constructed. The model is implemented and solved using COMSOL software. The water evaporation rate is determined using a nonequilibrium method with the rate constant parameterKrthat has been studied. The effects of different vapor pressures (1000, 5000, and 9000 Pa), initial moisture contents (0.3, 0.4, and 0.5 water saturation), drying temperatures (323, 333, and 343 K), and intrinsic permeability for cortex part (10−13, 10−14, 10−15 m2) on vacuum drying process were studied. The results facilitate a better understanding of the porous medium vacuum drying process that nearer to the reality.
Numerical Analysis for Stochastic Partial Differential Delay Equations with Jumps
Authors: Li Yan , Hu Junhao
Published: May 2013

We investigate the convergence rate of Euler-Maruyama method for a class of stochastic partial differential delay equations driven by both Brownian motion and Poisson point processes. We discretize in space by a Galerkin method and in time by using a stochastic exponential integrator. We generalize some results of Bao et al. (2011) and Jacob et al. (2009) in finite dimensions to a class of stochastic partial differential delay equations with jumps in infinite dimensions.
Event-Triggered Reliable Control in Networked Control Systems with Probabilistic Actuator Faults
Authors: Zhai Yuming , Yan Ruixia , Liu Haifeng , Liu Jinliang
Published: May 2013

This paper introduces a novel event-triggered scheme into networked control systems which is used to determine when to transmit the newly sampled state information to the controller. Considering the effect of the network transmission delay and probabilistic actuator fault with different failure rates, a new actuator fault model is proposed under this event-triggered scheme. Then, criteria for the exponential mean square stability (EMSS) and criteria for codesigning both the feedback and the trigger parameters are derived by using Lyapunov functional method. These criteria are obtained in the form of linear matrix inequalities. A simulation example is employed to show that our event-triggered scheme can lead to a larger release period than some existing ones.
Synthesis, Structural, and Electrical Properties of Pure PbTiO3Ferroelectric Ceramics
Authors: Chaudhari Vijendra A. , Bichile Govind K.
Published: May 2013

Single-phase polycrystalline samples of lead titanate with perovskite structure have been synthesized using solid-state reaction technique. The processing parameters have been optimized to obtain phase pure, dense, crack-free, and homogeneous samples. The sintering behavior of PT-powders has been investigated using X-ray diffraction patterns. The X-ray powder diffraction data have been analyzed to confirm the phase formation and phase purity, to obtain unit cell parameters and unit cell volume. The porosity of the samples has been obtained through X-ray density and bulk density. The average particle sizes of the phase pure samples were obtained from the X-ray peak width using Scherrer’s formula. The influence of sintering temperature and time on the microstructure of samples has also been studied by carrying out SEM investigations. The notable feature of this microstructure study shows that the samples sintered at 900°C for 12 hours possess a fairly uniform grain distribution. The electrical behavior (complex impedance Z*, complex permittivityε*, etc.) of the samples sintered at 900°C for 12 hours has been studied by complex impedance spectroscopy. The temperature variation of real permittivity gives evidence of the ferroelectric phase transition as well as of the relaxation behavior.
Staggered-Grid Finite Difference Method with Variable-Order Accuracy for Porous Media
Authors: Gao Jinghuai , Zhang Yijie
Published: May 2013

The numerical modeling of wave field in porous media generally requires more computation time than that of acoustic or elastic media. Usually used finite difference methods adopt finite difference operators with fixed-order accuracy to calculate space derivatives for a heterogeneous medium. A finite difference scheme with variable-order accuracy for acoustic wave equation has been proposed to reduce the computation time. In this paper, we develop this scheme for wave equations in porous media based on dispersion relation with high-order staggered-grid finite difference (SFD) method. High-order finite difference operators are adopted for low-velocity regions, and low-order finite difference operators are adopted for high-velocity regions. Dispersion analysis and modeling results demonstrate that the proposed SFD method can decrease computational costs without reducing accuracy.
Opioid Mechanism Involvement in the Synergism Produced by the Combination of Diclofenac and Caffeine in the Formalin Model
Authors: Flores-Ramos José María , Díaz-Reval M. Irene
Published: May 2013

Analgesics can be administered in combination with caffeine for improved analgesic effectiveness in a process known as synergism. The mechanisms by which these combinations produce synergism are not yet fully understood. The aim of this study was to analyze whether the administration of diclofenac combined with caffeine produced antinociceptive synergism and whether opioid mechanisms played a role in this event. The formalin model was used to evaluate the antinociception produced by the oral administration of diclofenac, caffeine, or their combination. Opioid involvement was analyzed through intracerebroventricular (i.c.v.) administration of naloxone followed by the oral administration of the study drugs. Diclofenac presented a dose-dependent effect, with a mean effective dose (ED50) of 6.7 mg/kg. Caffeine presented an analgesic effect with a 17–36% range. The combination of subeffective doses of each of the two drugs presented the greatest synergism with an effect of 57.7 ± 5.6%. The maximal antinociceptive effect was obtained with the combination of 10.0 mg/kg diclofenac and 1.0 mg/kg of caffeine, with an effect of 76.7 ± 5.6%. The i.c.v. administration of naloxone inhibited the effect of diclofenac, both separately and combined. In conclusion, caffeine produces antinociceptive synergism when administered in combination with diclofenac, and this synergism is partially mediated by opioid mechanisms at the central level.
Rainfall Rate Duration Study for Performance Assessment of Satellite Communication Links
Authors: Cerqueira Jorge L. , Assis Mauro S.
Published: May 2013

The duration of rainfall events as a function of precipitation rate is investigated in this paper. The experimental data used in this study were measured along a rain gauge
network with 8 pluviographs located in the Amazon region. The most important point to be highlighted in this study is the evidence of a correlation between rain and fade events
durations observed in a 12 GHz satellite link. This result is quite important under the engineering point of view, once it can be used in the design of improvement techniques for low availability satellite systems.
Exacerbated Airway Toxicity of Environmental Oxidant Ozone in Mice Deficient inNrf2
Authors: Cho Hye-Youn , Gladwell Wesley , Yamamoto Masayuki , Kleeberger Steven R.
Published: May 2013

Ozone (O3) is a strong oxidant in air pollution that has harmful effects on airways and exacerbates respiratory disorders. The transcription factor Nrf2 protects airways from oxidative stress through antioxidant response element-bearing defense gene induction. The present study was designed to determine the role of Nrf2 in airway toxicity caused by inhaled O3in mice. For this purpose,Nrf2-deficient (Nrf2-/-) and wild-type (Nrf2+/+) mice received acute and subacute exposures to O3. Lung injury was determined by bronchoalveolar lavage and histopathologic analyses. Oxidation markers and mucus hypersecretion were determined by ELISA, and Nrf2 and its downstream effectors were determined by RT-PCR and/or Western blotting. Acute and sub-acute O3exposures heightened pulmonary inflammation, edema, and cell death more severely inNrf2-/-mice than inNrf2+/+mice. O3caused bronchiolar and terminal bronchiolar proliferation in both genotypes of mice, while the intensity of compensatory epithelial proliferation, bronchial mucous cell hyperplasia, and mucus hypersecretion was greater inNrf2-/-mice than inNrf2+/+mice. Relative toNrf2+/+, O3augmented lung protein and lipid oxidation more highly inNrf2-/-mice. Results suggest thatNrf2deficiency exacerbates oxidative stress and airway injury caused by the environmental pollutant O3.
A New Approach for Solving Fractional Partial Differential Equations
Authors: Meng Fanwei
Published: May 2013

We propose a new approach for solving fractional partial differential equations based on a nonlinear fractional complex transformation and the general Riccati equation and apply it to solve the nonlinear time fractional biological population model and the (4+1)-dimensional space-time fractional Fokas equation. As a result, some new exact solutions for them are obtained. This approach can be suitable for solving fractional partial differential equations with more general forms than the method proposed by S. Zhang and H.-Q. Zhang (2011).
Synthesis of Clinical-Grade [18F]-Fluoroestradiol as a Surrogate PET Biomarker for the Evaluation of Estrogen Receptor-Targeting Therapeutic Drug
Authors: Dixit Manish , Shi Jianfeng , Wei Ling , Afari George , Bhattacharyya Sibaprasad
Published: May 2013

16α-[18F]-fluoroestradiol ([18F]FES), a steroid-based positron emission tomography (PET) tracer, has emerged as a dependable tracer for the evaluation and management of estrogen receptor-positive (ER+) breast cancer patients. We have developed a fully automatic, one-pot procedure for the synthesis of [18F]FES using the Eckert & Ziegler (E & Z) radiomodular system. After [18F]fluorination, the intermediate was hydrolyzed with 2.0 M HCl twice and neutralized with sodium bicarbonate. After high-performance liquid chromatography (HPLC) purification, the decay-corrected radiochemical yield and purity of [18F]FES were 40 ± 5.0% (n=12) and >97%, respectively. The product was stable up to 10 h. Total synthesis time including HPLC purification was 80 min. This new, fully automated rapid synthetic procedure provided high and reproducible yields of [18F]FES. Quality control (QC) tests showed that the [18F]FES produced by this method met all specifications for human injection.
Cumulative Risk Assessment Toolbox: Methods and Approaches for the Practitioner
Authors: MacDonell Margaret M. , Haroun Lynne A. , Teuschler Linda K. , Rice Glenn E. , Hertzberg Richard C. , Butler James P. , Chang Young-Soo , Clark Shanna L. , Johns Alan P. , Perry Camarie S. , Garcia Shannon S. , Jacobi John H. , Scofield Marcienne A.
Published: May 2013

The historical approach to assessing health risks of environmental chemicals has been to evaluate them one at a time. In fact, we are exposed every day to a wide variety of chemicals and are increasingly aware of potential health implications. Although considerable progress has been made in the science underlying risk assessments for real-world exposures, implementation has lagged because many practitioners are unaware of methods and tools available to support these analyses. To address this issue, the US Environmental Protection Agency developed a toolbox of cumulative risk resources for contaminated sites, as part of a resource document that was published in 2007. This paper highlights information for nearly 80 resources from the toolbox and provides selected updates, with practical notes for cumulative risk applications. Resources are organized according to the main elements of the assessment process: (1) planning, scoping, and problem formulation; (2) environmental fate and transport; (3) exposure analysis extending to human factors; (4) toxicity analysis; and (5) risk and uncertainty characterization, including presentation of results. In addition to providing online access, plans for the toolbox include addressing nonchemical stressors and applications beyond contaminated sites and further strengthening resource accessibility to support evolving analyses for cumulative risk and sustainable communities.
Antiproliferative Effect and the Isolated Compounds ofPouzolzia indica
Authors: Sangsuwon Chanyapat , Jiratchariyakul Weena , U-pratya Yaowalak , Kummalue Tanawan
Published: May 2013

Previous report showed the high potent antiproliferative effect of the methanolic part extracted from the aerial parts ofPouzolzia indicaon NB4 and HT93A acute leukemic cell lines with the IC50values of 28.5 and 49.8 μg/mL, respectively. The bioassay-guided fractionation of the methanolic part gave 5 fractions, that is, FFI–FFV. FFII, FFIII, and FFIV inhibited the above leukemic cell lines with the IC50values of 15.1 (FFII), 14.4 (FFIII), 32.1 (FFIV), and 31.0 (FFII), 9.7 (FFIII), 10.5 (FFIV) μg/mL, respectively. The compounds in these fractions were isolated using chromatographic technique. FFII contained friedelin1, 28-hydroxy-3-friedelanone2, and 7-methoxy-coumarin3. FFIII contained 6, 7-dimethoxy-coumarin4, scopoletin5, methyl caffeate6. FFIV contained sitosteryl glucoside7and a supposed glycosphingolipid8. The chemical structures were elucidated by spectroscopic methods.
Characterization and Photocatalytic Activity of TiO2Nanotube Films Prepared by Anodization
Authors: Wang Wen-Yu , Chen Bo-Ruei
Published: May 2013

Titanium dioxide nanotube (TNT) arrays were prepared in electrolytes containing fluoride by anodic oxidation. Different preparation parameters were investigated in order to evaluate their effects on length and inner diameter of nanotube, including weight ratio of glycerol to water, anodization voltage, electrolysis time, bath temperature, and electrolyte solution pH. The well defined and highly ordered TNT arrays were formed in electrolyte containing 40, and 20% water. The inner diameter of TNT was observed to increase as anodization voltage increased across the range of 10–40 V. The length of TNT was affected simultaneously by both anodization voltage and electrolysis time. The inner diameter and length depend on bath temperature below 60°C. The morphology of TNT was well defined and highly ordered only at electrolyte solution pH of 6 across the pH range of 2–10. Photocatalysis of methylene blue showed that reaction rate constants by TNT films were higher than P-25 films at comparable thickness. Reaction rate constants by TNT films increased as film thickness increased, but the enhancement was retarded when the length of TNT reached 2200 nm which appeared to be the limited penetration of incident UV light.
A P2P Framework for Developing Bioinformatics Applications in Dynamic Cloud Environments
Authors: Lin Chun-Hung Richard , Wen Chun-Hao , Lin Ying-Chih , Tung Kuang-Yuan , Lin Rung-Wei , Lin Chun-Yuan
Published: May 2013

Bioinformatics is advanced from in-house computing infrastructure to cloud computing for tackling the vast quantity of biological data. This advance enables large number of collaborative researches to share their works around the world. In view of that, retrieving biological data over the internet becomes more and more difficult because of the explosive growth and frequent changes. Various efforts have been made to address the problems of data discovery and delivery in the cloud framework, but most of them suffer the hindrance by a MapReduce master server to track all available data. In this paper, we propose an alternative approach, called PRKad, which exploits aPeer-to-Peer(P2P) model to achieve efficient data discovery and delivery. PRKad is a Kademlia-based implementation withRound-Trip-Time(RTT) as the associated key, and it locates data according toDistributed Hash Table(DHT) and XOR metric. The simulation results exhibit that our PRKad has the low link latency to retrieve data. As an interdisciplinary application of P2P computing for bioinformatics, PRKad also provides good scalability for servicing a greater number of users in dynamic cloud environments.
Fully Discrete Finite Element Approximation for the Stabilized Gauge-Uzawa Method to Solve the Boussinesq Equations
Authors: Pyo Jae-Hong
Published: May 2013

The stabilized Gauge-Uzawa method (SGUM), which is a 2nd-order projection type algorithm used to solve Navier-Stokes equations, has been newly constructed in the work of Pyo, 2013. In this paper, we apply the SGUM to the evolution Boussinesq equations, which model the thermal driven motion of incompressible fluids. We prove that SGUM is unconditionally stable, and we perform error estimations on the fully discrete finite element space via variational approach for the velocity, pressure, and temperature, the three physical unknowns. We conclude with numerical tests to check accuracy and physically relevant numerical simulations, the Bénard convection problem and the thermal driven cavity flow.