bluuebunny/crossref_metadata_2025 huggingface dataset:
A sensitive fluorescence method for monitoring the kinetics of microemulsion polymerization
Authors: Feng Haike , Dan Yi , Zhao Yue
Published: March 2010

We present a fluorescence method that allows one to monitor the kinetics of microemulsion polymerization of very low monomer contents (water-to-monomer ratio can readily be superior to 1000). The microemulsion polymerization of methyl methacrylate (MMA) was investigated using N-(2-anthracene)methacrylamide (AnMA) as the probe whose fluorescence emission intensity was proportional to the conversion of MMA into the polymer. The real-time-measurement results show that in the regime of very low monomer contents, the surfactant exerted a profound effect on the kinetic process. In a microemulsion containing 0.1 wt% of MMA with respect to water, with the anionic surfactant of sodium dodecyl sulfate (SDS), the fast polymerization was preceded by an induction period whose length increased with reducing the concentration of the water-soluble initiator of potassium persulfate (KPS). By contrast, with the non-ionic surfactant of polyoxyethylene (20) oleyl ether (Brij98), the induction period was short and the decrease in the KPS concentration mainly resulted in a decrease of the reaction rate. The unprecedented sensitivity of this fluorescence method made it possible to access kinetic data of microemulsion polymerization with very low monomer contents for the first time, providing new insight into the effects of surfactant and initiator on this heterophase polymerization process.
Synthesis, photophysics, and electrochemistry of thiophene–pyridine and thiophene–pyrimidine dyad comonomers
Authors: Bolduc Andréanne , Dufresne Stéphane , Hanan Garry S. , Skene W. G.
Published: March 2010

A series of new π-conjugated donor (D) and acceptor (A) dyad comonomers were prepared using Suzuki coupling protocols. The D–A comonomers consisting of thiophene/bithiophene as donors and pyridine/pyrimidine as acceptors were prepared to investigate their photophysical and electrochemical properties. The dyads were spectroscopically confirmed to be highly conjugated. This was further supported by the X-ray crystal structure of the bithophene–pyridine dyad that showed all the heterocycles to be coplanar. It was further found that the fluorescence yields (Φfl) of the dyads were highly dependent on the number of thiophenes. The bithiophene derivatives exhibited Φfl values ≥ 0.3 while the thiophene derivatives did not fluoresce. The suppressed fluorescence observed for the thiophene derivatives was due to their higher triplet energy resulting in efficient intersystem crossing (ISC) to the triplet state with ΦISC ≥ 0.8. This was confirmed both by time-resolved and steady-state measurements. The singlet excited state of both thiophene and bithiophene dyads was deactivated solely by either fluorescence and (or) ISC. Owing to their donor and acceptor character, the dyads could be oxidized and reduced both electrochemically and photochemically to afford the radical cation and anion, respectively.
Climatic factors affecting radial growth of Betula ermanii and Betula platypylla in Kamchatka
Authors: Doležal Jiri , Ishii Hiroaki , Kyncl Tomáš , Takahashi Koichi , Vetrova Valentina P. , Homma Kosuke , Sumida Akihiro , Hara Toshihiko
Published: March 2010

Radial growth responses to climate were studied in two species of birch broadly distributed across Kamchatka Peninsula. Wood cores were obtained in different locations and environments, from upper to lower treelines, and from wet maritime sites at the Pacific to the subcontinental interior of the peninsula. Response functions were calculated using the four longest meteorological records (1920s–2000) in Kamchatka. In Betula ermanii Cham., the dominant species in mountains and maritime woodlands, ring width in high-elevation (500–600 m) trees increased with warm and less rainy June and July and decreased with rainy/snowy cool weather during the prior September and October. Radial growth in B. ermanii low-elevation trees increased with higher winter precipitation, suggesting that water from melting snow prevents water stress and possibly desiccation in low-elevation trees. In Betula platyphylla Sukaczev, a common taiga species in interior Kamchatka, low summer temperatures limited growth at its upper distributional limit (300–350 m) and in cool, wet sites dominated by Picea ajanensis Lindl. et Gord. On drier sites dominated by Larix cajanderii Mayr., growth was limited by warm April and dry June weather. Variable responses along elevation–continentality gradients reinforce the necessity of a site-dependent differentiation for the assessment of impacts of climate change on species performance and geographic range shifts.
Leaf area duration in natural range and exotic Pinus taeda
Authors: Albaugh Timothy J. , Allen H. Lee , Stape José Luiz , Fox Thomas R. , Rubilar Rafael A. , Carlson Colleen A. , Pezzutti Raul
Published: March 2010

Exotic Pinus taeda L. plantations may be more productive than native ones. Several hypotheses may explain this difference; however, process models with a light-interception-driving variable cannot test these hypotheses without foliage display first being quantified in native and exotic trees. We quantified leaf area duration in North Carolina, USA (natural), and Gobernador Virasoro, Argentina (exotic), with no additional nutrients and optimum fertilizer treatments. More (60%–100%) foliage was displayed but for a shorter (∼86 fewer days) time per fascicle in the exotics than in the naturals. Study inference was limited, with only one native and one exotic site. However, while the sites were markedly different in soils, climate, resource availability, and genetics, and we observed significant differences in fascicle display and longevity, most fascicles at both sites survived two growing seasons: the one in which they were produced and the subsequent one. This robust finding indicates it would be reasonable to use two growing seasons for fascicle longevity in process modeling to test hypotheses explaining growth differences in native and exotic loblolly. Fertilization had no effect on any exotic tree parameter, but it increased natural tree fascicle number (24%) and length (30%).
Wood stiffness and strength as selection traits for sawn timber in Acacia auriculiformis
Authors: Hai Phi Hong , Hannrup B. , Harwood C. , Jansson G. , Van Ban Do
Published: March 2010

Acacia auriculiformis A. Cunn. ex Benth. is an important planting tree species, but little attention has been paid to its wood properties, such as shrinkage, stiffness, strength, and basic density, which are important for use in structural and appearance-grade timber applications. Here we report the genetic variation in static bending stiffness and strength of wood in a 5½-year-old clone trial in southern Vietnam and the genotypic correlations among these traits and tree diameter, wood shrinkage, and basic density. There was significant variation in stiffness and strength among 40 randomly selected clones. Clonal repeatability (H2) was high for stiffness and moderate for strength. There was no consistent pattern of difference between heartwood and sapwood for the estimates of H2 for stiffness and strength, whereas the estimates of H2 were lower for heartwood density than for sapwood density. Diameter showed a significant negative genotypic correlation with stiffness but a nonsignificant correlation with strength. Genotypic correlations between density and stiffness, and density and strength, were positive, but only the latter was significant. Stiffness and strength were not significantly correlated with wood shrinkage. There is potential to simultaneously improve tree growth, wood basic density, and the mechanical properties of juvenile wood of this species.
Sugar maple seedling carbon assimilation at the northern limit of its range: the importance of seasonal light
Authors: Kwit Matthew C. , Rigg Lesley S. , Goldblum David
Published: March 2010

Using in situ light curves and understory seasonal light measurements the importance of canopy avoidance was evaluated for a population of sugar maple ( Acer saccharum Marsh.) seedlings living at the boreal ecotone in Lake Superior Provincial Park, Ontario, Canada. At higher latitudes, the time period associated with canopy avoidance is shorter and occurs at cooler temperatures, increasing the risk of frost damage. In 2008, leaf-out began 5 days prior to the last frost of the season. By modeling the potential carbon gain of seedlings, it is clear that the short time period prior to canopy leaf-out still contributes a disproportionate amount of carbon to the overall budget of seedlings. Of the total seasonal carbon gain, 80.6% was assimilated in the initial 15 days following sugar maple seedling leaf-out. Based on our model, by leafing out only 6 days earlier than the average seedling leaf-out date, ∼200% more carbon could be assimilated during the course of the growing season. Vegetation phenology is cued by climatic triggers — as climate changes so too will phenological responses. These mechanisms add to the overall carbon budget of seedlings; recognizing these mechanisms is essential to thoroughly understand the natural history of this species.
Regional and ecological patterns in interior Douglas-fir climate–growth relationships in British Columbia, Canada
Authors: Griesbauer Hardy P. , Green D. Scott
Published: March 2010

How climate change will affect tree growth across species’ geographic and climatic ranges remains a critical knowledge gap. Tree-ring data were analyzed from 33 interior Douglas-fir ( Pseudotsuga menziesii var. glauca (Beissn.) Franco) stands spanning wide geographic and climatic conditions in the interior of British Columbia to gain insights into how within-species growth responses to climate can vary based on local environmental conditions over a broad climatic and geographic range, including populations growing at the species’ range and climatic margins. Populations growing in relatively warm and dry climates had growth patterns correlated mostly with annual precipitation, whereas populations growing in high-elevation wet and cold climates had growth patterns correlated with snowfall, winter and annual temperatures, and ocean–atmosphere climate systems. Populations growing at climatic extremes (e.g., coldest, driest, warmest) in each study region had the strongest responses to climate. Projected climate change may negatively influence Douglas-fir productivity across most of its range, and populations growing near the species’ climatic limits may provide early and strong indications of future responses.
COMPLETE TRAFFIC PATTERNS AROUND A T-SHAPED INTERSECTION
Authors: HUANG DING-WEI
Published: March 2010

We propose Asymmetric Simple Exclusion Processes to analyze the traffic states around a T-shaped intersection. The system consists of six roadways connected by the intersection. There are nine control-parameters separated into three categories: injection αi, removal βi, and turning Pi, (where i = 1, 2, 3). As these nine parameters change, traffic states on each roadway reveal a two-phase transition: free flow (F) and jam (J). Together, there can be 64 (=26) possible combinations for the traffic phases. We observe 63 distinct phases. We analyze three major causes of congestion:

(1) increase of traffic demand simulated by injection αi;

(2) decrease of roadway capacity simulated by removal βi;

(3) redistribution of traffic pattern simulated by turning Pi.

In case (1), congestion can be confined to the roadways heading toward the intersection. In case (2), spillovers can be observed and congestion will pervade the whole system. In case (3), congestion can be triggered by both increasing Pi and decreasing Pi. The phase diagram can be a convenient tool to summarize the results of numerical simulations. We also compare the unsignalized intersection to an intersection regulated by traffic signals. We find that the operation of traffic signals is very inefficient in resolving the congestion around a T-shaped intersection.
GENERALIZED PROJECTIVE SYNCHRONIZATION AND PARAMETERS ESTIMATION OF TWO NEW HYPERCHAOTIC SYSTEMS WITH FULLY UNCERTAIN PARAMETERS
Authors: ZHU CONG-XU
Published: March 2010

This paper investigates adaptive generalized projective synchronization (GPS) between two novel hyperchaotic systems with different structure and fully uncertain parameters. Based on the Lyapunov stability theorem and the adaptive control theory, GPS between the two hyperchaotic systems is achieved by proposing a new adaptive controller and a novel parameters estimation update law. Strict theoretical proof is put forward. Numerical simulations are presented to demonstrate the effectiveness of the proposed GPS scheme and verify the theoretical results.
INTEGRATION OVER CONNECTIONS IN THE DISCRETIZED GRAVITATIONAL FUNCTIONAL INTEGRALS
Authors: KHATSYMOVSKY V. M.
Published: March 2010

The result of performing integrations over connection type variables in the path integral for the discrete field theory may be poorly defined in the case of non-compact gauge group with the Haar measure exponentially growing in some directions. This point is studied in the case of the discrete form of the first-order formulation of the Einstein gravity theory. Here the result of interest can be defined as generalized function (of the rest of variables of the type of tetrad or elementary areas), i.e. a functional on a set of probe functions. To define this functional, we calculate its values on the products of components of the area tensors, the so-called moments. The resulting distribution (in fact, probability distribution) has singular (δ-function-like) part with support in the nonphysical region of the complex plane of area tensors and regular part (usual function) which decays exponentially at large areas. As we discuss, this also provides suppression of large edge lengths which is important for internal consistency, if one asks whether gravity on short distances can be discrete. Some other features of the obtained probability distribution including occurrence of the local maxima at a number of the approximately equidistant values of area are also considered.
NILPOTENT QUANTUM MECHANICS
Authors: FRYDRYSZAK ANDRZEJ M.
Published: March 2010

We develop a generalized quantum mechanical formalism based on the nilpotent commuting variables (η-variables). In the nonrelativistic case such formalism provides natural realization of a two-level system (qubit). Using the space of η-wavefunctions, η-Hilbert space and generalized Schrödinger equation we study properties of pure multiqubit systems and also properties of some composed, hybrid models: fermion–qubit, boson–qubit. The fermion–qubit system can be truly supersymmetric, with both SUSY partners having identical spectra. It is a novel feature that SUSY transformations relate here only nilpotent object. The η-eigenfunctions of the Hamiltonian for the qubit–qubit system give the set of Bloch vectors as a natural basis.
QCD PRECISION MEASUREMENTS AND STRUCTURE FUNCTION EXTRACTION AT A HIGH STATISTICS, HIGH ENERGY NEUTRINO SCATTERING EXPERIMENT: NuSOnG
Authors: ADAMS T. , BATRA P. , BUGEL L. , CAMILLERI L. , CONRAD J. M. , DE GOUVÊA A. , FISHER P. H. , FORMAGGIO J. A. , JENKINS J. , KARAGIORGI G. , KOBILARCIK T. R. , KOPP S. , KYLE G. , LOINAZ W. A. , MASON D. A. , MILNER R. , MOORE R. , MORFÍN J. G. , NAKAMURA M. , NAPLES D. , NIENABER P. , OLNESS F. I. , OWENS J. F. , PATE S. F. , PRONIN A. , SELIGMAN W. G. , SHAEVITZ M. H. , SCHELLMAN H. , SCHIENBEIN I. , SYPHERS M. J. , TAIT T. M. P. , TAKEUCHI T. , TAN C. Y. , VAN DE WATER R. G. , YAMAMOTO R. K. , YU J. Y.
Published: March 2010

We extend the physics case for a new high-energy, ultra-high statistics neutrino scattering experiment, NuSOnG (Neutrino Scattering On Glass) to address a variety of issues including precision QCD measurements, extraction of structure functions, and the derived Parton Distribution Functions (PDF's). This experiment uses a Tevatron-based neutrino beam to obtain a sample of Deep Inelastic Scattering (DIS) events which is over two orders of magnitude larger than past samples. We outline an innovative method for fitting the structure functions using a parametrized energy shift which yields reduced systematic uncertainties. High statistics measurements, in combination with improved systematics, will enable NuSOnG to perform discerning tests of fundamental Standard Model parameters as we search for deviations which may hint of "Beyond the Standard Model" physics.
THE STUDY OF ELLIPTIC FLOWS OF IDENTIFIED HADRONS IN Au + Au COLLISIONS AT $\sqrt{s_{NN}} = 200~{\rm GeV}$ WITH A QUARK COMBINATION MODEL
Authors: ZHAO HONG-WEI , HAN WEI , SONG JUN , SHAO FENG-LAN
Published: March 2010

The elliptic flows of identified hadrons in Au + Au collisions at [Formula: see text] are systematically investigated within the framework of quark (re)combination/coalescence. The results indicate that the quark combination mechanism can describe self-consistently the elliptic flows of various hadrons from low to intermediate pT range.
MULTIPLE LOCAL LAGRANGIANS FOR n-COMPONENT SUPER-KORTEWEG–DE VRIES-TYPE BI-HAMILTONIAN SYSTEMS
Authors: OĞUZ ÖMER , YAZICI DEVRIM
Published: March 2010

The multiple Lagrangian formalism is constructed for n-component Korteweg–de Vries (KdV) type superintegrable systems. They all admit bi-Hamiltonian structure. The first two Lagrangians are local and degenerate. They contain Clebsch potentials for velocity fields and momentum maps in kinetic term. The first local Lagrangian for n-component supermodified KdV (smKdV) is also obtained by employing the multicomponent super-Miura transformation.
Glass Transition Temperature and Its Relevance in Food Processing
Authors: Roos Yrjö H.
Published: March 2010

Amorphous, noncrystalline solids are typical of low water content and frozen foods. Solids in these foods, e.g., confectionary, dehydrated foods, cereal foods, and frozen foods, often form nonequilibrium glass-like structures. The glassy state of the solids forms during food processing in a reversible glass transition. Vitrification can occur in numerous glassy states that exhibit various relaxations around the glass transition. The success of freeze drying, spray drying, and extrusion and the stability of dehydrated foods against flow, collapse, and crystallization is based on the control of the glassy state during the dehydration process and storage. Encapsulation processes often use glass-forming materials to entrap dispersed components or improve retention of volatiles. Plasticization of the noncrystalline structures by temperature or water reduce relaxation times exponentially above the glass transition, which results in rapid deterioration. Critical values for water activity and water content express the level of water plasticization leading to glass transition in food storage.
Food Powders Flowability Characterization: Theory, Methods, and Applications
Authors: Juliano Pablo , Barbosa-Cánovas Gustavo V.
Published: March 2010

Characterization of food powders flowability is required for predicting powder flow from hoppers in small-scale systems such as vending machines or at the industrial scale from storage silos or bins dispensing into powder mixing systems or packaging machines. This review covers conventional and new methods used to measure flowability in food powders. The method developed by Jenike (1964) for determining hopper outlet diameter and hopper angle has become a standard for the design of bins and is regarded as a standard method to characterize flowability. Moreover, there are a number of shear cells that can be used to determine failure properties defined by Jenike's theory. Other classic methods (compression, angle of repose) and nonconventional methods (Hall flowmeter, Johanson Indicizer, Hosokawa powder tester, tensile strength tester, powder rheometer), used mainly for the characterization of food powder cohesiveness, are described. The effect of some factors preventing flow, such as water content, temperature, time consolidation, particle composition and size distribution, is summarized for the characterization of specific food powders with conventional and other methods. Whereas time-consuming standard methods established for hopper design provide flow properties, there is yet little comparative evidence demonstrating that other rapid methods may provide similar flow prediction.
Fate of Starch in Food Processing: From Raw Materials to Final Food Products
Authors: Delcour Jan A. , Bruneel Charlotte , Derde Liesbeth J. , Gomand Sara V. , Pareyt Bram , Putseys Joke A. , Wilderjans Edith , Lamberts Lieve
Published: March 2010

Starch, an essential component of an equilibrated diet, is present in cereals such as common and durum wheat, maize, rice, and rye, in roots and tubers such as potato and cassava, and in legumes such as peas. During food processing, starch mainly undergoes nonchemical transformations. Here, we focus on the occurrence of starch in food raw materials, its composition and properties, and its transformations from raw material to final products. We therefore describe a number of predominant food processes and identify research needs. Nonchemical transformations that are dealt with include physical damage to starch, gelatinization, amylose-lipid complex formation, amylose crystallization, and amylopectin retrogradation. A main focus is on wheat-based processes. (Bio)chemical modifications of starch by amylolytic enzymes are dealt with only in the context of understanding the starch component in bread making.
Effects of bladder outlet obstruction on properties of Ca2+-activated K+channels in rat bladder
Authors: Kita Masafumi , Yunoki Takakazu , Takimoto Koichi , Miyazato Minoru , Kita Kaori , de Groat William C. , Kakizaki Hidehiro , Yoshimura Naoki
Published: March 2010

In this study, we investigated the effects of bladder outlet obstruction (BOO) on the expression and function of large conductance (BK) and small conductance (SK) Ca2+-activated K+channels in detrusor smooth muscle. The bladder from adult female Sprague-Dawley rats with 6-wk BOO were used. The mRNA expression of the BK channel α-subunit, β1-, β2-, and β4-subunits and SK1, SK2, and SK3 channels were investigated using real-time RT-PCR. All subunits except for the BK-β2, SK2, and SK3 channels were predominantly expressed in the detrusor smooth muscle rather than in the mucosa. The mRNA expression of the BK channel α-subunit was not significantly changed in obstructed bladders. However, the expression of the BK channel β1-subunit and the SK3 channel was remarkably increased in obstructed bladders. On the other hand, the expression of the BK channel β4-subunit was decreased as the severity of BOO-induced bladder overactivity progressed. In detrusor smooth muscle strips from obstructed bladders, blockade of BK channels by iberiotoxin (IbTx) or charybdotoxin (CTx) and blockade of SK channels by apamin increased the amplitude of spontaneous contractions. These blockers also increased the contractility and affinity of these strips for carbachol during cumulative applications. The facilitatory effects elicited by these K+channel blockers were larger in the strips from obstructed bladders compared with control bladders. These results suggest that long-term exposure to BOO for 6 wk enhances the function of both BK and SK types of Ca2+-activated K+channels in the detrusor smooth muscle to induce an inhibition of bladder contractility, which might be a compensatory mechanism to reduce BOO-induced bladder overactivity.
Initiating treadmill training in late middle age offers modest adaptations in Ca2+handling but enhances oxidative damage in senescent rat skeletal muscle
Authors: Thomas Melissa M. , Vigna Chris , Betik Andrew C. , Tupling A. Russell , Hepple Russell T.
Published: March 2010

Aging skeletal muscle shows an increased time to peak force and relaxation and a decreased specific force, all of which could relate to changes in muscle Ca2+handling. The purpose of this study was to determine if Ca2+-handling protein content and function are decreased in senescent gastrocnemius muscle and if initiating a training program in late middle age (LMA, 29 mo old) could improve function in senescent (34- to 36-mo-old) muscle. LMA male Fischer 344 × Brown-Norway rats underwent 5–7 mo of treadmill training. Aging resulted in a decrease in maximal sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) activity and a decrease in Ca2+release rate but no change in Ca2+uptake rate. Efficiency of the Ca2+pump was increased with age, as was the content of SERCA2a. Training caused a further increase in SERCA2a content. Aging also caused an increase in protein carbonyl and reactive nitrogen species damage accumulation, and both further increased with training. Consistent with the increase in oxidative damage, heat shock protein 70 content was increased with age and further increased with training. Together, these results suggest that while initiating exercise training in LMA augments the age-related increase in expression of heat shock protein 70 and the more efficient SERCA2a isoform, it did not prevent the decrease in SERCA activity and exacerbated oxidative damage in senescent gastrocnemius muscle.
Multiple mechanisms act to maintain kidney oxygenation during renal ischemia in anesthetized rabbits
Authors: Evans Roger G. , Eppel Gabriela A. , Michaels Sylvia , Burke Sandra L. , Nematbakhsh Mehdi , Head Geoffrey A. , Carroll Joan F. , O'Connor Paul M.
Published: March 2010

We examined the mechanisms that maintain stable renal tissue Po2 during moderate renal ischemia, when changes in renal oxygen delivery (Ḋo2) and consumption (V̇o2) are mismatched. When renal artery pressure (RAP) was reduced progressively from 80 to 40 mmHg, V̇o2 (−38 ± 7%) was reduced more than Ḋo2 (−26 ± 4%). Electrical stimulation of the renal nerves (RNS) reduced Ḋo2 (−49 ± 4% at 2 Hz) more than V̇o2 (−30 ± 7% at 2 Hz). Renal arterial infusion of angiotensin II reduced Ḋo2 (−38 ± 3%) but not V̇o2 (+10 ± 10%). Despite mismatched changes in Ḋo2 and V̇o2, renal tissue Po2 remained remarkably stable at ≥40 mmHg RAP, during RNS at ≤2 Hz, and during angiotensin II infusion. The ratio of sodium reabsorption to V̇o2 was reduced by all three ischemic stimuli. None of the stimuli significantly altered the gradients in Pco2 or pH across the kidney. Fractional oxygen extraction increased and renal venous Po2 fell during 2-Hz RNS and angiotensin II infusion, but not when RAP was reduced to 40 mmHg. Thus reduced renal V̇o2 can help prevent tissue hypoxia during mild renal ischemia, but when renal V̇o2 is reduced less than Ḋo2, other mechanisms prevent a fall in renal Po2. These mechanisms do not include increased efficiency of renal oxygen utilization for sodium reabsorption or reduced washout of carbon dioxide from the kidney, leading to increased oxygen extraction. However, increased oxygen extraction could be driven by altered countercurrent exchange of carbon dioxide and/or oxygen between renal arteries and veins.
Pentosan polysulfate treatment preserves renal autoregulation in ANG II-infused hypertensive rats via normalization of P2X1receptor activation
Authors: Guan Zhengrong , Fuller Barry S. , Yamamoto Tatsuo , Cook Anthony K. , Pollock Jennifer S. , Inscho Edward W.
Published: March 2010

Inflammatory factors are elevated in animal and human subjects with hypertension and renal injury. We hypothesized that inflammation contributes to hypertension-induced renal injury by impairing autoregulation and microvascular reactivity to P2X1receptor activation. Studies were conducted in vitro using the blood-perfused juxtamedullary nephron preparation. Rats receiving ANG II (60 ng/min) infusion were treated with the anti-inflammatory agent pentosan polysulfate (PPS) for 14 days. The magnitude and progression of hypertension were similar in ANG II and ANG II+PPS-treated rats (169 ± 5 vs. 172 ± 2 mmHg). Afferent arterioles from control rats exhibited normal autoregulatory behavior with diameter decreasing from 18.4 ± 1.6 to 11.4 ± 1.7 μm when perfusion pressure was increased from 70 to 160 mmHg. In contrast, pressure-mediated vasoconstriction was markedly attenuated in ANG II-treated rats, and diameter remained essentially unchanged over the range of perfusion pressures. However, ANG II-treated rats receiving PPS exhibited normal autoregulatory behavior compared with ANG II alone rats. Arteriolar reactivity to ATP and β,γ-methylene ATP was significantly reduced in ANG II hypertensive rats compared with controls. Interestingly, PPS treatment preserved normal reactivity to P2 and P2X1receptor agonists despite the persistent hypertension. The maximal vasoconstriction was 79 ± 3 and 81 ± 2% of the control diameter for ATP and β,γ-methylene ATP, respectively, similar to responses in control rats. PPS treatment significantly reduced α-smooth muscle actin staining in afferent arterioles and plasma transforming growth factor-β1 concentration in ANG II-treated rats. In conclusion, PPS normalizes autoregulation without altering ANG II-induced hypertension, suggesting that inflammatory processes reduce P2X1receptor reactivity and thereby impair autoregulatory behavior in ANG II hypertensive rats.
High-resolution spatial measurements of ventilation-perfusion heterogeneity in rats
Authors: Robertson H. Thomas , Krueger Melissa A. , Lamm Wayne J. E. , Glenny Robb W.
Published: March 2010

This study was designed to validate a high-resolution method to measure regional ventilation (V̇a) in small laboratory animals, and to compare regional V̇a and perfusion (Q̇) before and after methacholine-induced bronchoconstriction. A mixture of two different colors of 0.04-μm fluorescent microspheres (FMS) was aerosolized and administered to five anesthetized, mechanically ventilated rats. Those rats also received an intravenous injection of a mixture of two different colors of 15-μm FMS to measure regional blood flow (Q̇). Five additional rats were labeled with aerosol and intravenous FMS, injected with intravenous methacholine, and then relabeled with a second pair of aerosol and intravenous FMS colors. After death, the lungs were reinflated, frozen, and sequentially sliced in 16-μm intervals on an imaging cryomicrotome set to acquire signal for each of the FMS colors. The reconstructed lung images were sampled using randomly placed 3-mm radius spheres. V̇a within each sphere was estimated from the aerosol fluorescence signal, and Q̇ was estimated from the number of 15-μm FMS within each sphere. Method error ranged from 6 to 8% for Q̇ and 0.5 to 4.0% for V̇a. The mean coefficient of variation for Q̇ was 17%, and for V̇a was 34%. The administration of methacholine altered the distribution of both V̇a and Q̇ within lung regions, with a change in V̇a distribution nearly twice as large as that seen for Q̇. The methacholine-induced changes in V̇a were not associated with compensatory shifts in Q̇. Cryomicrotome images of FMS markers provide a high-resolution, anatomically specific means of measuring regional V̇a/Q̇ responses in the rat.
Local hindlimb antioxidant infusion does not affect muscle glucose uptake during in situ contractions in rat
Authors: Merry T. L. , Dywer R. M. , Bradley E. A. , Rattigan S. , McConell G. K.
Published: March 2010

There is evidence that reactive oxygen species (ROS) contribute to the regulation of skeletal muscle glucose uptake during highly fatiguing ex vivo contraction conditions via AMP-activated protein kinase (AMPK). In this study we investigated the role of ROS in the regulation of glucose uptake and AMPK signaling during low-moderate intensity in situ hindlimb muscle contractions in rats, which is a more physiological protocol and preparation. Male hooded Wistar rats were anesthetized, and then N-acetylcysteine (NAC) was infused into the epigastric artery (125 mg·kg−1·h−1) of one hindlimb (contracted leg) for 15 min before this leg was electrically stimulated (0.1-ms impulse at 2 Hz and 35 V) to contract at a low-moderate intensity for 15 min. The contralateral leg did not receive stimulation or local NAC infusion (rest leg). NAC infusion increased ( P < 0.05) plasma cysteine and cystine (by ∼360- and 1.4-fold, respectively) and muscle cysteine (by 1.5-fold, P = 0.001). Although contraction did not significantly alter muscle tyrosine nitration, reduced (GSH) or oxidized glutathione (GSSG) content, S-glutathionylation of protein bands at ∼250 and 150 kDa was increased ( P < 0.05) ∼1.7-fold by contraction, and this increase was prevented by NAC. Contraction increased ( P < 0.05) skeletal muscle glucose uptake 20-fold, AMPK phosphorylation 6-fold, ACCβ phosphorylation 10-fold, and p38 MAPK phosphorylation 60-fold, and the muscle fatigued by ∼30% during contraction and NAC infusion had no significant effect on any of these responses. This was despite NAC preventing increases in S-glutathionylation with contraction. In conclusion, unlike during highly fatiguing ex vivo contractions, local NAC infusion during in situ low-moderate intensity hindlimb contractions in rats, a more physiological preparation, does not attenuate increases in skeletal muscle glucose uptake or AMPK signaling.
Cys-Loop Ligand-Gated Chloride Channels in Dorsal Unpaired Median Neurons ofLocusta migratoria
Authors: Janssen Daniel , Derst Christian , Rigo Jean-Michel , Van Kerkhove Emmy
Published: March 2010

In insects, inhibitory neurotransmission is generally associated with members of the cys-loop ligand-gated anion channels, such as the glutamate-gated chloride channel (GluCl), the GABA-gated chloride channels (GABACl), and the histamine-gated chloride channels (HisCl). These ionotropic receptors are considered established target sites for the development of insecticides, and therefore it is necessary to obtain a better insight in their distribution, structure, and functional properties. Here, by combining electrophysiology and molecular biology techniques, we identified and characterized GluCl, GABACl, and HisCl in dorsal unpaired median (DUM) neurons of Locust migratoria. In whole cell patch-clamp recordings, application of glutamate, GABA, or histamine induced rapidly activating ionic currents. GluCls were sensitive to ibotenic acid and blocked by picrotoxin and fipronil. The pharmacological profile of the L. migratoria GABACl fitted neither the vertebrate GABAAnor GABACreceptor and was similar to the properties of the cloned Drosophila melanogaster GABA receptor subunit (Rdl). The expression of Rdl-like subunit-containing GABA receptors was shown at the molecular level using RT-PCR. Sequencing analysis indicated that the orthologous GABACl of D. melanogaster CG10357-A is expressed in DUM neurons of L. migratoria. Histamine-induced currents exhibited a fast onset and desensitized completely on continuous application of histamine. In conclusion, within the DUM neurons of L. migratoria, we identified three different cys-loop ligand-gated anion channels that use GABA, glutamate, or histamine as their neurotransmitter.
MeCP2 Is Required for Normal Development of GABAergic Circuits in the Thalamus
Authors: Zhang Zhong-Wei , Zak Joseph D. , Liu Hong
Published: March 2010

Methyl-CpG binding protein 2 (MeCP2) is highly expressed in neurons in the vertebrate brain, and mutations of the gene encoding MeCP2 cause the neurodevelopmental disorder Rett syndrome. This study examines the role of MeCP2 in the development and function of thalamic GABAergic circuits. Whole cell recordings were carried out in excitatory neurons of the ventrobasal complex (VB) of the thalamus and in inhibitory neurons of the reticular thalamic nucleus (RTN) in acute brain slices from mice aged P6 through P23. At P14–P16, the number of quantal GABAergic events was decreased in VB neurons but increased in RTN neurons of Mecp2-null mice, without any change in the amplitude or kinetics of quantal events. There was no difference between mutant and wild-type mice in paired-pulse ratios of evoked GABAergic responses in the VB or the RTN. On the other hand, unitary responses evoked by minimal stimulation were decreased in the VB but increased in the RTN of mutants. Similar changes in the frequency of quantal events were observed at P21–P23 in both the VB and RTN. At P6, however, quantal GABAergic transmission was altered only in the VB not the RTN. Immunostaining of vesicular GABA transporter showed opposite changes in the number of GABAergic synaptic terminals in the VB and RTN of Mecp2-null mice at P18–P20. The loss of MeCP2 had no significant effect on intrinsic properties of RTN neurons recorded at P15–P17. Our findings suggest that MeCP2 differentially regulates the development of GABAergic synapses in excitatory and inhibitory neurons in the thalamus.
Control of the Firing Patterns of Vibrissa Motoneurons by Modulatory and Phasic Synaptic Inputs: A Modeling Study
Authors: Harish Omri , Golomb David
Published: March 2010

Vibrissa motoneurons (vMNs) generate rhythmic firing that controls whisker movements, even without cortical, cerebellar, or sensory inputs. vMNs receive serotonergic modulation from brain stem areas, which mainly increases their persistent sodium conductance ( gNaP) and, possibly, phasic input from a putative central pattern generator (CPG). In response to serotonergic modulation or just-suprathreshold current steps, vMNs fire at low rates, below the firing frequency of exploratory whisking. In response to periodic inputs, vMNs exhibit nonlinear suprathreshold resonance in frequency ranges of exploratory whisking. To determine how firing patterns of vMNs are determined by their 1) intrinsic ionic conductances and 2) responses to periodic input from a putative CPG and to serotonergic modulation, we construct and analyze a single-compartment, conductance-based model of vMNs. Low firing rates are supported in extended regimes by adaptation currents and the minimal firing rate decreases with gNaPand increases with M-potassium and h-cation conductances. Suprathreshold resonance results from the locking properties of vMN firing to stimuli and from reduction of firing rates at low frequencies by slow M and afterhyperpolarization potassium conductances. h conductance only slightly affects the suprathreshold resonance. When a vMN is subjected to a small periodic CPG input, serotonergically induced gNaPelevation may transfer the system from quiescence to a firing state that is highly locked to the CPG input. Thus we conclude that for vMNs, the CPG controls firing frequency and phase and enables bursting, whereas serotonergic modulation controls transitions from quiescence to firing unless the CPG input is sufficiently strong.
Triband Compact Antenna for Multistandard Terminals and User's Hand Effect
Authors: Koubeissi M. , Mouhamadou M. , Decroze C. , Carsenat D. , Monédière T.
Published: March 2010

A novel compact wideband triband antenna for mobile terminals based on PIFA element is proposed. The antenna operates at the following frequency bands: Wireless-LAN 802.11 b, g, a and WiMAX 3.5 GHz. The antenna was studied by means of numerical simulations as well as the ground plane dimensions and user's hand effects. The overall size of the radiating element which is  mm makes it suitable for use in terminals and appropriate to integrated as an internal laptop antenna. The measured bandwidths show that the proposed antenna can cover three bands (2.39–2.48 GHz), (3.36–3.76 GHz), and (4.7–6.3 GHz) and the total efficiency is better than 90%. The radiation patterns of the antenna were carried in an anechoic chamber and are given to demonstrate the antenna's performance.
Existence and Approximation of Fixed Points for Set-Valued Mappings
Authors: Reich Simeon , Zaslavski AlexanderJ
Published: March 2010

Taking into account possibly inexact data, we study both existence and approximation of fixed points for certain set-valued mappings of contractive type. More precisely, we study the existence of convergent iterations in the presence of computational errors for two classes of set-valued mappings. The first class comprises certain mappings of contractive type, while the second one contains mappings satisfying a Caristi-type condition.
Applications of Nanofluids: Current and Future
Authors: Wong Kaufui V. , De Leon Omar
Published: March 2010

Nanofluids are suspensions of nanoparticles in fluids that show significant enhancement of their properties at modest nanoparticle concentrations. Many of the publications on nanofluids are about understanding their behavior so that they can be utilized where straight heat transfer enhancement is paramount as in many industrial applications, nuclear reactors, transportation, electronics as well as biomedicine and food. Nanofluid as a smart fluid, where heat transfer can be reduced or enhanced at will, has also been reported. This paper focuses on presenting the broad range of current and future applications that involve nanofluids, emphasizing their improved heat transfer properties that are controllable and the specific characteristics that these nanofluids possess that make them suitable for such applications.
A Class of Weak Hopf Algebras
Authors: Cheng Dongming
Published: March 2010

We introduce a class of noncommutative and noncocommutative
weak Hopf algebras with infinite Ext quivers and study their structure. We decompose
them into a direct sum of two algebras. The coalgebra structures of these
weak Hopf algebras are described by their Ext quiver. The weak Hopf extension
of Hopf algebra Hn
has a quotient Hopf algebra and a sub‐Hopf algebra which are
isomorphic to Hn.
Downregulation of Epidermal Growth Factor Receptor Expression Contributes toα-TEA's Proapoptotic Effects in Human Ovarian Cancer Cell Lines
Authors: Shun Ming-Chieh , Yu Weiping , Park Sook-Kyung , Sanders Bob G. , Kline Kimberly
Published: March 2010

RRR-α-tocopherol derivativeα-TEA (RRR-α-tocopherol ether-linked acetic acid analog) has been shown to be a potent antitumor agent both in vivo and in vitro. In this study, we investigated the effects ofα-TEA on the expression of epidermal growth factor receptor (EGFR) family members, ErbB1, 2 and 3, and the role of ErbB 2 and 3 inα-TEA-induced apoptosis and suppression of Akt, FLIP and survivin in the cisplatin-sensitive (A2780S) and -resistant (A2780/CP70R) human ovarian cancer cell lines. Data show thatα-TEA's ability to induced apoptosis was associated with reduced expression of ErbB1 (cisplatin-resistant cells), 2 and 3 (both cell types) and reduced levels of the phosphorylated (active) form of Akt; as well as, reduced levels of FLIP and survivin proteins in both cell types. Ectopic overexpression and siRNA knockdown studies showed that ErbB2, ErbB3, Akt, FLIP and survivin are involved inα-TEA-induce apoptosis and thatα-TEA downregulates FLIP and survivin via suppression of pAkt, which is mediated by ErbB2 and ErB3. Thus,α-TEA is a potent pro-apoptotic agent for both cisplatin-sensitive and -resistant ovarian cancer cell lines in cell culture and it produces cell death, at least in part, by downregulation of members of the EGFR family.
Overlap between Irritable Bowel Syndrome and Inflammatory Bowel Disease
Authors: Spiller Robin C.
Published: March 2010

While recent studies have indicated that the colonic mucosa in irritable bowel syndrome (IBS) shows an increase in inflammatory cells, this ‘inflammation’ is quantitatively less than in inflammatory bowel disease (IBD) and of a different nature with a predominance of mast cells, particularly in female patients. Inflammation can arise via numerous pathways including infection, stress, food allergy and changes in gut microbiota. Low-grade mucosal inflammation throughout the colon and including the terminal ileum can be seen for many months after an attack of acute gastroenteritis and is a feature of post-infective IBS. Measurements of gut permeability also show a prolonged increase in both the small and large bowel in both post-infective IBS and IBS with diarrhoea predominance. This has been linked to visceral hypersensitivity, but whether this is causal or an epiphenomenon remains uncertain. Studying the risk factors for post-infective IBS has shown the importance of both local and microbiological factors, as well as psychological factors, including adverse life events, anxiety and depression. Stress in both animals and humans can activate mast cells, which (by increasing gut permeability) may allow activation of the systemic immune system. Demonstration of the importance of the low-grade inflammation observed awaits definitive large scale trials of agents designed to specifically reverse these changes.
The Placebo Response Rate in Irritable Bowel Syndrome and Inflammatory Bowel Disease
Authors: Sands Bruce E.
Published: March 2010

The placebo response is the efficacy attributable to a treatment that is thought to have no specific pharmacologic effect on the condition being treated. Although potentially helpful in clinical practice, high and unpredictable placebo response rates present a major impediment to the success of clinical trials in inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). Diverse factors contribute to the placebo response rates observed in clinical trials. These include patient characteristics, physician factors, frequency of study visits, characteristics of the outcome measures, concomitant treatments, regression to the mean, properties of the intervention and treatment setting, timing of the primary endpoint and natural history of the condition. Measures that may minimize the placebo response in IBD clinical trials include early timing of the primary endpoint, minimizing the number of study visits, restricting the patient population to those with documented inflammation (such as elevated biomarkers of inflammation or evidence of mucosal inflammation), including patients with more severe symptoms (i.e. greater disease activity) and enrolling patients with prior failure of immune modulators or biologics. Attempts to limit the placebo response in IBS studies have proven more difficult. Factors associated with higher placebo response rates in IBS studies include longer duration of treatment, greater number of office visits, frequency of administration of study intervention and overall treatment effect of the active agent under study. In the future, improved understanding of the factors that drive the placebo response rate should lead to more efficient study design and drug development.
Acquisition, Evolution and Maintenance of the Normal Gut Microbiota
Authors: Macfarlane G.T. , Macfarlane L.E.
Published: March 2010

The gut is sterile at birth, but is rapidly colonised by faecal and vaginal bacteria of maternal origin. Over the succeeding weeks, months and years, a complex microbiota develops that plays a major role in host physiology. While the digestive tract is colonised to varying degrees by micro-organisms throughout its length, due to acid pH and the short retention time of gastric contents, bacterial numbers in the stomach are usually low. The rapid passage of digestive materials through the upper gut does not provide time for significant bacterial growth to occur, but cell numbers increase considerably in the distal ileum. The rate of movement of intestinal contents slows in the colon, which facilitates the development of complex bacterial communities. The large intestine is an intricate ecosystem that contains a complex microbiota composed of several hundred different types of bacteria. The growth and metabolism of microbial communities in the large intestine are determined by many factors, such as diet, environment and host physiological processes, as well as the anatomic structure of the digestive tract, disease, immunity, host genetics, drugs and ageing. Modifications in diet and host immune system activity, as well as physiological changes in the digestive tract affect microbiota composition in older people. The elderly have fewer bifidobacteria and higher numbers of enterobacteria and clostridia than young adults. Increased antibiotic use in older people and simply going into hospital have been shown to change bacterial community structure in the colonic microbiota, although the metabolic significance of this is unclear.