bluuebunny/crossref_metadata_2025 huggingface dataset:
CONTEXTUALITY, INCOMPATIBILITY AND BIASED INFERENCE IN A QUANTUM-LIKE FORMULATION OF COMPUTATIONAL TRUST
Authors: ASHTIANI MEHRDAD , AZGOMI MOHAMMAD ABDOLLAHI
Published: September 2014

Trust models play an important role in computational environments. One of the main aims of the work undertaken in this domain is to provide a model that can better describe the socio-technical nature of computational trust. It has been recently shown that quantum-like formulations in the field of human decision making can better explain the underlying nature of these types of processes. Based on this research, the aim of this paper is to propose a novel model of trust based on quantum probabilities as the underlying mathematics of quantum theory. It will be shown that by using this new mathematical framework, we will have a powerful mechanism to model the contextuality property of trust. Also, it is hypothesized that many events or evaluations in the context of trust can be and should be considered as incompatible, which is unique to the noncommutative structure of quantum probabilities. The main contribution of this paper will be that, by using the quantum Bayesian inference mechanism for belief updating in the framework of quantum theory, we propose a biased trust inference mechanism. This mechanism allows us to model the negative and positive biases that a trustor may subjectively feel toward a certain trustee candidate. It is shown that by using this bias, we can model and describe the exploration versus exploitation problem in the context of trust decision making, recency effects for recently good or bad transactions, filtering pessimistic and optimistic recommendations that may result in good-mouthing or bad-mouthing attacks, the attitude of the trustor toward risk and uncertainty in different situations and the pseudo-transitivity property of trust. Finally, we have conducted several experimental evaluations in order to demonstrate the effectiveness of the proposed model in different scenarios.
Cosmological constant and Euclidean space from nonperturbative quantum torsion
Authors: Dzhunushaliev Vladimir
Published: September 2014

Heisenberg's nonperturbative quantization technique is applied to the nonperturbative quantization of gravity. An infinite set of equations for all Green's functions is obtained. An approximation is considered where: (a) the metric remains as a classical field; (b) the affine connection can be decomposed into classical and quantum parts; (c) the classical part of the affine connection is the Christoffel symbols; (d) the quantum part is the torsion. Using a scalar and vector fields approximation it is shown that nonperturbative quantum effects give rise to a cosmological constant and an Euclidean solution.
The existence of small prime gaps in subsets of the integers
Authors: Benatar Jacques
Published: September 2014

We consider the problem of finding small prime gaps in various sets [Formula: see text]. Following the work of Goldston–Pintz–Yıldırım, we will consider collections of natural numbers that are well-controlled in arithmetic progressions. Letting qn denote the nth prime in [Formula: see text], we will establish that for any small constant ϵ > 0, the set {qn | qn+1 - qn ≤ ϵ log n} constitutes a positive proportion of all prime numbers. Using the techniques developed by Maynard and Tao, we will also demonstrate that [Formula: see text] has bounded prime gaps. Specific examples, such as the case where [Formula: see text] is an arithmetic progression have already been studied and so the purpose of this paper is to present results for general classes of sets.
Series representing transcendental numbers that are not U-numbers
Authors: Alkan Emre
Published: September 2014

Using integral representations with carefully chosen rational functions as integrands, we find new families of transcendental numbers that are not U-numbers, according to Mahler's classification, represented by a series whose terms involve rising factorials and reciprocals of binomial coefficients analogous to Apéry type series. Explicit descriptions of these numbers are given as linear combinations with coefficients lying in a suitable real algebraic extension of rational numbers using elementary functions evaluated at arguments belonging to the same field. In this way, concrete examples of transcendental numbers which can be expressed as combinations of classical mathematical constants such as π and Baker periods are given together with upper bounds on their wnmeasures.
ZnS NANOFLOWERS ON GRAPHENE FOR USE AS A HIGH-PERFORMANCE PHOTOCATALYST
Authors: BIN ZENG , HUI LONG
Published: September 2014

The nanocomposites of graphene loaded– ZnS nanoflowers (GR– ZnS ) had been successfully prepared. Materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectra (FTIR), photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS) spectra. A possible formation mechanism of this architecture was proposed. The experimental results revealed that these nanoflowers exhibited excellent UV-light photocatalytic activities for pollutant methyl orange (MO) dye degradation. These new nanostructures were expected to show considerable potential applications in the water treatment.
PHASE STABILITY OF L21 PHASE IN Co-BASED HEUSLER ALLOYS
Authors: UMETSU RIE Y. , OKUBO AKINARI , NAGASAKO MAKOTO , OHTSUKA MAKOTO , KAINUMA RYOSUKE , ISHIDA KIYOHITO
Published: September 2014

Order–disorder phase transition temperature from L21 to B2 phase, [Formula: see text], in Co -based Heusler alloys was systematically investigated based on the Braggs–Williams–Gorsky (BWG) approximation. Because height of [Formula: see text] closely correlates to phase stability of the L21 phase, confirmation of [Formula: see text] would be a key to obtain a highly ordered L21 phase. From modification with the BWG approximation it was shown that the degree of order indicated temperature dependence, namely, the degree of order decreased above around 0.6 [Formula: see text] and reached zero at [Formula: see text]. Therefore, it should be better to select the Co -based Heusler alloys with a higher value of [Formula: see text] if the higher degree of order in the L21 phase is desired by thermal annealing at as low temperature as possible. From powder neutron diffraction (ND) studies of Co 2Y Ga (Y = Ti , V , Cr , Mn and Fe ) alloys it was actually confirmed that materials with higher value of [Formula: see text] indicated higher degree of order even in the same annealing temperature. Studies for the phase state in Co – Ti – Fe – Ga films also showed that a height of [Formula: see text] concretely correlated to the phase stability of the L21 phases, that is, the specimen with higher value of [Formula: see text] was easy to obtain with a higher degree of order.
POLYCRYSTALLINE CO-BASED FULL-HEUSLER-ALLOY FILMS FOR SPINTRONIC DEVICES
Authors: HIROHATA A. , SAGAR J. , FLEET L. R. , ENDO H.
Published: September 2014

For the implementation of Heusler-alloy films into next-generation magnetic memories and storages, the optimization of their polycrystalline nature is critical. In this review, we identify two key parameters for the optimization; grain volume for interfacial magnetism and activation volume for magnetic dynamics. We establish correlations between these structural and magnetic volumes and magnetic behavior and then optimize these properties. The optimized polycrystalline films possess exchange bias of 250 Oe induced by low-temperature annealing (400°C for 30 min.), which is induced by the grain volume matching between the Heusler-alloy and antiferromagnetic layers. Despite the matching size measuring 7–8 nm in diameter, the magnetic activation volumes are estimated to be almost 80 nm which is one order of magnitude greater than that for epitaxial films. These values satisfy the requirements for next-generation spintronic device applications and unambiguously prove the great potential of the polycrystalline Heusler-alloy films for future spintronic applications.
TETRAGONAL HEUSLER-LIKE Mn–Ga ALLOYS BASED PERPENDICULAR MAGNETIC TUNNEL JUNCTIONS
Authors: MA QINLI , SUGIHARA ATSUSHI , SUZUKI KAZUYA , ZHANG XIANMIN , MIYAZAKI TERUNOBU , MIZUKAMI SHIGEMI
Published: September 2014

Films of the Mn -based tetragonal Heusler-like alloys, such as Mn – Ga , exhibit a large perpendicular magnetic anisotropy (PMA), small damping constant, small saturation magnetization and large spin polarizations. These properties are attractive for the application to the next generation high density spin-transfer-torque (STT) magnetic random access memory (STT-MRAM). We reviewed the structure, magnetic properties and Gilbert damping of the alloy films with large PMA, and the current status of research on tunnel magnetoresistance (TMR) in perpendicular magnetic tunnel junctions (p-MTJs) based on Mn -based tetragonal Heusler-like alloy electrode, and also discuss the issues for the application of those to STT-MRAM.
Oxidation processes and their effects on the magnetic remanence of Early Cretaceous subaerial basalts from Sierra Chica de Córdoba, Argentina
Authors: Geuna S. E. , Lagorio S. L. , Vizán H.
Published: September 2014

We carried out magnetic analyses on a sequence of Cretaceous alkaline–transitional subaerial basalts of Córdoba Province, Argentina, which have high-Ti magnetite as the main opaque phase. Three different groups are identified based on the degree of high-temperature oxidation during the lava extrusion, combined with superimposed maghemitization and hematization. In the first group, titanomagnetites are optically homogeneous or exhibit coarse intergrowths with ilmenite. The magnetic susceptibility and its variation with temperature and magnetic field point to Ti-poorer compositions than those indicated by electron microprobe, which is interpreted as due to low-temperature oxidation with subsolvus microexsolution. The second group of basalts suffered moderate high-temperature oxidation, with crowded exsolved ilmenite laths within a Ti-poor magnetite
ss
host, followed by maghemitization and hematite replacement. The third group shows a strongly advanced degree of low-temperature alteration, with the virtual disappearance of magnetite. Based on magnetic properties and field tests applied to the magnetic remanence, we interpret that maghemitization and hematization must have been responsible for the acquisition of a stable magnetic remanence, in the presence of hydrothermal fluids coeval with volcanism. The most advanced degree of alteration, typical of highly porous amygdaloidal lava flows and volcanic breccias, occurred later, probably due to weathering.
Magma flow within dykes in submarine hyaloclastite environments: an AMS study of the Miocene Cabo de Gata volcanic units
Authors: Porreca M. , Cifelli F. , Soriano C. , Giordano G. , Mattei M.
Published: September 2014

The Miocene Cabo de Gata volcanic arc in SE Spain comprises a wide variety of volcanic facies and eruptive styles in subaqueous to subaerial environments. In the SW sector of the area, 5–100 m-thick, NNW–SSE-orientated dykes feed and intrude submarine hyaloclastite deposits. We analysed the anisotropy of magnetic susceptibility (AMS) of six dykes and five hyaloclastite sites from three volcanic units: the Cerro Cañadillas, Los Frailes, and El Barronal formations. The main magnetic minerals are primary low-Ti titanomagnetite and magnetite. The AMS ellipsoids in the dykes are generally oblate-triaxial in shape, with magnetic foliations subparallel to the dyke walls. Kinematic field evidence supports the inferred flow directions deduced from magnetic lineation and imbrication of magnetic foliation. The geometric relationships between dyke margins and AMS axes indicate that dykes at El Barronal were emplaced via prevalent subvertical upward magma flow. The inferred flow directions are reproduced well by analogue models of AMS simulating magma migration in dykes with a diapiric geometry. The other dykes were emplaced by lateral magma propagation. Conversely, hyaloclastite shows a large scatter of the AMS axes reflecting different degrees of fragmentation. We observe a gradual increase in scatter in the AMS from confined dykes to fragmented hyaloclastite.
Volcanic glass and its suitability to recover the ancient geomagnetic field strength
Authors: Ferk A. , Leonhardt R. , Hess K.-U. , Dingwell D. B.
Published: September 2014

The determination of the past ancient magnetic field intensity is typically very difficult and error prone. Fresh volcanic glass has been suggested to be an ideal material for obtaining direction and strength of the magnetic field. Domain state bias is generally absent, thermal alteration is normally negligible and, as demonstrated in this study, cooling-rate differences can be corrected for. Major issues remaining include alteration and the origin of the remanence: that is, whether it is a true thermo-, a thermochemical or, for altered samples, a chemical remanence. Hydration, devitrification and perlitization lead to incorrect estimates of the palaeointensity, which are very difficult to recognize as the palaeointensity analysis does not easily expose these biasing effects and points towards ‘reliable’ results. Particular care on sampling and/or volatile measurements are necessary to overcome these drawbacks.
Percolation of the interacting elastic stress fields of aligned cracks as an alternative explanation of critical crack densities
Authors: Heffer Kes
Published: September 2014

The concept that the lithosphere is in a general critical, or near-critical, mechanical state has previously assumed spatial intersection of fractures at the critical point. This paper provides an initial basis for an alternative mechanism in which elastic interactions between aligned, open, spatially separated (micro-)cracks in rock can, by themselves, lead to a continuous phase change at a critical threshold of crack density lower than that required for crack coalescence. The existence of a critical density of aligned cracks is first demonstrated on a regular 2D hexagonal grid when subjected to a central stress perturbation; at this critical density the elastic tensile stress interactions have a long-range effect. From the results of those calculations an approximation of the tensile stress field around a crack in 3D is provided. The percolation behaviour of such 3D bodies is discussed and a critical crack density in 3D for elastic interaction of 0.035 is deduced. This falls within the range of crack densities (0.015–0.045) interpreted from observations of shear-wave splitting in many different rocks. The possibility that critical crack interactions can be mostly elastic provides one explanation of the long-range nature of correlations in flowrate fluctuations in oilfields without large-scale seismicity.
Phosphate and acidosis act synergistically to depress peak power in rat muscle fibers
Authors: Nelson Cassandra R. , Debold Edward P. , Fitts Robert H.
Published: September 2014

Skeletal muscle fatigue is characterized by the buildup of H+ and inorganic phosphate (Pi), metabolites that are thought to cause fatigue by inhibiting muscle force, velocity, and power. While the individual effects of elevated H+ or Pi have been well characterized, the effects of simultaneously elevating the ions, as occurs during fatigue in vivo, are still poorly understood. To address this, we exposed slow and fast rat skinned muscle fibers to fatiguing levels of H+ (pH 6.2) and Pi (30 mM) and determined the effects on contractile properties. At 30°C, elevated Pi and low pH depressed maximal shortening velocity ( Vmax) by 15% (4.23 to 3.58 fl/s) in slow and 31% (6.24 vs. 4.55 fl/s) in fast fibers, values similar to depressions from low pH alone. Maximal isometric force dropped by 36% in slow (148 to 94 kN/m2) and 46% in fast fibers (148 to 80 kN/m2), declines substantially larger than what either ion exerted individually. The strong effect on force combined with the significant effect on velocity caused peak power to decline by over 60% in both fiber types. Force-stiffness ratios significantly decreased with pH 6.2 + 30 mM Pi in both fiber types, suggesting these ions reduced force by decreasing the force per bridge and/or increasing the number of low-force bridges. The data indicate the collective effects of elevating H+ and Pi on maximal isometric force and peak power are stronger than what either ion exerts individually and suggest the ions act synergistically to reduce muscle function during fatigue.
Enhanced breast cancer cell adherence to the lung endothelium via PAF acetylhydrolase inhibition: a potential mechanism for enhanced metastasis in smokers
Authors: Kispert Shannon E. , Marentette John O. , McHowat Jane
Published: September 2014

Cancer deaths are primarily caused by distant metastases, rather than by primary tumor growth; however, the role of smoking in metastasis remains unclear. We demonstrated previously that endothelial cell platelet-activating factor (PAF) production results in enhanced inflammatory cell recruitment to the lung. We propose that endothelial cell PAF accumulation plays a role in cancer cell migration to distal locations. We used cigarette smoke extract (CSE) to inhibit the activity of endothelial cell PAF acetylhydrolase (PAF-AH), which hydrolyzes and inactivates PAF, and determined whether this results in increased endothelial cell PAF accumulation and breast cancer adherence. Incubation of human lung microvascular endothelial cells (HMVEC-L) with CSE resulted in a significant inhibition of PAF-AH activity that was accompanied by increased PAF production and adherence of highly invasive MDA-MB-231 breast cancer cells. Pretreatment of HMVEC-L with ( S)-bromoenol lactone to inhibit calcium-independent phospholipase A2β (iPLA2β, which initiates endothelial cell PAF production) prior to CSE exposure resulted in complete inhibition of MDA-MB-231 cell adherence. Similarly, pretreatment of MDA-MB-231 cells with the PAF receptor antagonist Ginkgo biloba resulted in inhibition of adherence to the endothelium. Immunoblot analysis indicated an increase in MDA-MB-231 cell PAF receptor expression with CSE exposure. Taken together, our data indicate that CSE exposure increases endothelial cell PAF production, resulting in enhanced adherence of tumor cells to the endothelium. Our in vitro data indicate that increased tumor cell adherence would lead to enhanced metastasis formation in smokers. Potential therapeutic targets include endothelial cell iPLA2β or the tumor cell PAF receptor.
Cellular Mechanisms of Endoplasmic Reticulum Stress Signaling in Health and Disease. 3. Orchestrating the unfolded protein response in oncogenesis: an update
Authors: Manié Serge N. , Lebeau Justine , Chevet Eric
Published: September 2014

The endoplasmic reticulum (ER)-induced unfolded protein response (UPR) is an adaptive mechanism that is activated upon accumulation of misfolded proteins in the ER and aims at restoring ER homeostasis. In the past 10 years, the UPR has emerged as an important actor in the different phases of tumor growth. The UPR is transduced by three major ER resident stress sensors, which are protein kinase RNA-like ER kinase (PERK), activating transcription factor 6 (ATF6), and inositol-requiring enzyme-1 (IRE1). The signaling pathways elicited by those stress sensors have connections with metabolic pathways and with other plasma membrane receptor signaling networks. As such, the ER has an essential position as a signal integrator in the cell and is instrumental in the different phases of tumor progression. Herein, we describe and discuss the characteristics of an integrated signaling network that might condition the UPR biological outputs in a tissue- or stress-dependent manner. We discuss these issues in the context of the pathophysiological roles of UPR signaling in cancers.
Regulation of amniotic fluid volume: mathematical model based on intramembranous transport mechanisms
Authors: Brace Robert A. , Anderson Debra F. , Cheung Cecilia Y.
Published: September 2014

Experimentation in late-gestation fetal sheep has suggested that regulation of amniotic fluid (AF) volume occurs primarily by modulating the rate of intramembranous transport of water and solutes across the amnion into underlying fetal blood vessels. In order to gain insight into intramembranous transport mechanisms, we developed a computer model that allows simulation of experimentally measured changes in AF volume and composition over time. The model included fetal urine excretion and lung liquid secretion as inflows into the amniotic compartment plus fetal swallowing and intramembranous absorption as outflows. By using experimental flows and solute concentrations for urine, lung liquid, and swallowed fluid in combination with the passive and active transport mechanisms of the intramembranous pathway, we simulated AF responses to basal conditions, intra-amniotic fluid infusions, fetal intravascular infusions, urine replacement, and tracheoesophageal occlusion. The experimental data are consistent with four intramembranous transport mechanisms acting in concert: 1) an active unidirectional bulk transport of AF with all dissolved solutes out of AF into fetal blood presumably by vesicles; 2) passive bidirectional diffusion of solutes, such as sodium and chloride, between fetal blood and AF; 3) passive bidirectional water movement between AF and fetal blood; and 4) unidirectional transport of lactate into the AF. Further, only unidirectional bulk transport is dynamically regulated. The simulations also identified areas for future study: 1) identifying intramembranous stimulators and inhibitors, 2) determining the semipermeability characteristics of the intramembranous pathway, and 3) characterizing the vesicles that are the primary mediators of intramembranous transport.
Prevention of diabetic nephropathy by compound 21, selective agonist of angiotensin type 2 receptors, in Zucker diabetic fatty rats
Authors: Castoldi Giovanna , di Gioia Cira R. T. , Bombardi Camila , Maestroni Silvia , Carletti Raffaella , Steckelings U. Muscha , Dahlöf Bjorn , Unger Thomas , Zerbini Gianpaolo , Stella Andrea
Published: September 2014

The aim of this study was to evaluate the effect of compound 21 (C21), a selective AT2 receptor agonist, on diabetic nephropathy and the potential additive effect of C21, when associated with losartan treatment, on the development of albuminuria and renal fibrosis in Zucker diabetic fatty (ZDF) rats. The experiments lasted 15 wk (from 5 to 20 wk of age) and were performed in 40 ZDF rats and 12 control lean rats. ZDF rats were divided into 4 groups: 1) 9 rats were treated with losartan; 2) 10 rats were treated with C21; 3) 9 rats were treated with losartan plus C21; and 4) 12 rats were maintained without any treatment. ZDF rats showed an increase in blood glucose level, albuminuria, renal fibrosis, macrophage infiltration, and TNF-α expression and a reduction of glomerular nephrin expression compared with control lean rats. C21 treatment reduced renal glomerular, tubulointerstitial, and perivascular fibrosis, and macrophage infiltration and TNF-α expression in ZDF rats. C21 treatment caused a decrease in albuminuria in ZDF rats up to 11 wk of age. Losartan decreased macrophage infiltration, TNF-α expression, and renal glomerular and perivascular fibrosis, restored glomerular nephrin expression, but did not affect tubulointerstitial fibrosis. Losartan treatment caused a decrease in albuminuria in ZDF rats up to 15 wk of age. At the end of the protocol, only the combination of C21 plus losartan significantly reduced albuminuria in ZDF rats. These data demonstrate that C21 has beneficial effects on diabetic nephropathy, suggesting the combination of C21 and losartan as a novel pharmacological tool to slow the progression of nephropathy in type II diabetes.
c-Kit signaling determines neointimal hyperplasia in arteriovenous fistulae
Authors: Skartsis Nikolaos , Martinez Laisel , Duque Juan Camilo , Tabbara Marwan , Velazquez Omaida C. , Asif Arif , Andreopoulos Fotios , Salman Loay H. , Vazquez-Padron Roberto I.
Published: September 2014

Stenosis of arteriovenous (A-V) fistulae secondary to neointimal hyperplasia (NIH) compromises dialysis delivery, which worsens patients' quality of life and increases medical costs associated with the maintenance of vascular accesses. In the present study, we evaluated the role of the receptor tyrosine kinase c-Kit in A-V fistula neointima formation. Initially, c-Kit was found in the neointima and adventitia of human brachiobasilic fistulae, whereas it was barely detectable in control veins harvested at the time of access creation. Using the rat A-V fistula model to study venous vascular remodeling, we analyzed the spatial and temporal pattern of c-Kit expression in the fistula wall. Interestingly, c-Kit immunoreactivity increased with time after anastomosis, which concurred with the accumulation of cells in the venous intima. In addition, c-Kit expression in A-V fistulae was positively altered by chronic kidney failure conditions. Both blockade of c-Kit with imatinib mesylate (Gleevec) and inhibition of stem cell factor production with a specific short hairpin RNA prevented NIH in the outflow vein of experimental fistulae. In agreement with these data, impaired c-Kit activity compromised the development of NIH in A-V fistulae created in c-KitW/Wvmutant mice. These results suggest that targeting of the c-Kit signaling pathway may be an effective approach to prevent postoperative NIH in A-V fistulae.
Live nephron imaging by MRI
Authors: Qian Chunqi , Yu Xin , Pothayee Nikorn , Dodd Stephen , Bouraoud Nadia , Star Robert , Bennett Kevin , Koretsky Alan
Published: September 2014

The local sensitivity of MRI can be improved with small MR detectors placed close to regions of interest. However, to maintain such sensitivity advantage, local detectors normally need to communicate with the external amplifier through cable connections, which prevent the use of local detectors as implantable devices. Recently, an integrated wireless amplifier was developed that can efficiently amplify and broadcast locally detected signals, so that the local sensitivity was enhanced without the need for cable connections. This integrated detector enabled the live imaging of individual glomeruli using negative contrast introduced by cationized ferritin, and the live imaging of renal tubules using positive contrast introduced by gadopentetate dimeglumine. Here, we utilized the high blood flow to image individual glomeruli as hyperintense regions without any contrast agent. These hyperintense regions were identified for pixels with signal intensities higher than the local average. Addition of Mn2+allowed the simultaneous detection of both glomeruli and renal tubules: Mn2+was primarily reabsorbed by renal tubules, which would be distinguished from glomeruli due to higher enhancement in T1-weighted MRI. Dynamic studies of Mn2+absorption confirmed the differential absorption affinity of glomeruli and renal tubules, potentially enabling the in vivo observation of nephron function.
Physiology and pathophysiology of the renal Na-K-2Cl cotransporter (NKCC2)
Authors: Castrop Hayo , Schießl Ina Maria
Published: September 2014

The Na-K-2Cl cotransporter (NKCC2; BSC1) is located in the apical membrane of the epithelial cells of the thick ascending limb of the loop of Henle (TAL). NKCC2 facilitates ∼20–25% of the reuptake of the total filtered NaCl load. NKCC2 is therefore one of the transport proteins with the highest overall reabsorptive capacity in the kidney. Consequently, even subtle changes in NKCC2 transport activity considerably alter the renal reabsorptive capacity for NaCl and eventually lead to perturbations of the salt and water homoeostasis. In addition to facilitating the bulk reabsorption of NaCl in the TAL, NKCC2 transport activity in the macula densa cells of the TAL constitutes the initial step of the tubular-vascular communication within the juxtaglomerular apparatus (JGA); this communications allows the TAL to modulate the preglomerular resistance of the afferent arteriole and the renin secretion from the granular cells of the JGA. This review provides an overview of our current knowledge with respect to the general functions of NKCC2, the modulation of its transport activity by different regulatory mechanisms, and new developments in the pathophysiology of NKCC2-dependent renal NaCl transport.
Developmental increase in hippocampal endocannabinoid mobilization: role of metabotropic glutamate receptor subtype 5 and phospholipase C
Authors: Liang Shu-Ling , Alger Bradley E. , McCarthy Margaret M.
Published: September 2014

Endocannabinoids (eCBs) released from postsynaptic neurons mediate retrograde suppression of neurotransmitter release at central synapses. eCBs are crucial for establishing proper synaptic connectivity in the developing nervous system. Mobilization of eCBs is driven either by a rise in intracellular Ca2+ (depolarization-induced suppression of inhibition, DSI) or postsynaptic G protein-coupled receptors (GPCRs) that activate phospholipase C beta (PLCβ). To determine whether eCB mobilization changes between neonatal and juvenile ages, we used whole cell voltage-clamp recordings of CA1 neurons from rat hippocampal slices at postnatal days 1–18 (neonatal) and 19–43 (juvenile), because many neurophysiological parameters change dramatically between approximately postnatal days 18–20. We found that DSI was slightly greater in juveniles than in neonates, while eCB mobilization stimulated by GPCRs was unchanged. However, when DSI was elicited during GPCR activation, its increase was much greater in juveniles, suggesting that eCB mobilization caused by the synergy between the Ca2+ and GPCR pathways is developmentally upregulated. Western blotting revealed significant increases in both metabotropic type glutamate receptor 5 (mGluR5) and PLCβ1 proteins in juveniles compared with neonates. Responses to pharmacological activation or inhibition of PLC implied that eCB upregulation is associated with a functional increase in PLC activity. We conclude that synergistic eCB mobilization in hippocampal CA1 neurons is greater in juveniles than in neonates, and that this may result from increases in the mGluR5-PLCβ1 eCB pathway. The data enhance our understanding of the developmental regulation of the eCB system and may provide insight into diseases caused by improper cortical wiring, or the impact of cannabis exposure during development.
Activation of rostral ventromedial medulla neurons by noxious stimulation of cutaneous and deep craniofacial tissues
Authors: Khasabov Sergey G. , Malecha Patrick , Noack Joseph , Tabakov Janneta , Okamoto Keiichiro , Bereiter David A. , Simone Donald A.
Published: September 2014

The rostral ventromedial medulla (RVM) projects to the medullary and spinal dorsal horns and is a major source of descending modulation of nociceptive transmission. Traditionally, neurons in the RVM are classified functionally as ON, OFF, and NEUTRAL cells on the basis of responses to noxious cutaneous stimulation of the tail or hind paw. ON cells facilitate nociceptive transmission, OFF cells are inhibitory, whereas NEUTRAL cells are unresponsive to noxious stimuli and their role in pain modulation is unclear. Classification of RVM neurons with respect to stimulation of craniofacial tissues is not well defined. In isoflurane-anesthetized male rats, RVM neurons first were classified as ON (25.5%), OFF (25.5%), or NEUTRAL (49%) cells by noxious pinch applied to the hind paw. Pinching the skin overlying the temporomandibular joint (TMJ) altered the proportions of ON (39.2%), OFF (42.2%), and NEUTRAL (19.6%) cells. To assess the response of RVM cells to specialized craniofacial inputs, adenosine triphosphate (ATP; 0.01–1 mM) was injected into the TMJ and capsaicin (0.1%) was applied to the ocular surface. TMJ and ocular surface stimulation also resulted in a reduced proportion of NEUTRAL cells compared with hind paw pinch. Dose-effect analyses revealed that ON and OFF cells encoded the intra-TMJ concentration of ATP. These results suggest that somatotopy plays a significant role in the functional classification of RVM cells and support the notion that NEUTRAL cells likely are subgroups of ON and OFF cells. It is suggested that a portion of RVM neurons serve different functions in modulating craniofacial and spinal pain conditions.
Location matters: somatic and dendritic SK channels answer to distinct calcium signals
Authors: Rudolph Stephanie , Thanawala Monica S.
Published: September 2014

Voltage-dependent calcium channels (VDCCs) couple neuronal activity to diverse intracellular signals with exquisite spatiotemporal specificity. Using calcium imaging and electrophysiology, Jones and Stuart ( J Neurosci 33: 19396–19405, 2013) examined the intimate relationship between distinct types of VDCCs and small-conductance calcium-activated potassium (SK) channels that contribute to the compartmentalized control of excitability in the soma and dendrites of cortical pyramidal neurons. Here we discuss the importance of calcium domains for signal specificity, explore the possible functions and mechanisms for local control of SK channels, and highlight technical considerations for the optical detection of calcium signals.
Locomotor patterns in cerebellar ataxia
Authors: Martino G. , Ivanenko Y. P. , Serrao M. , Ranavolo A. , d'Avella A. , Draicchio F. , Conte C. , Casali C. , Lacquaniti F.
Published: September 2014

Several studies have demonstrated how cerebellar ataxia (CA) affects gait, resulting in deficits in multijoint coordination and stability. Nevertheless, how lesions of cerebellum influence the locomotor muscle pattern generation is still unclear. To better understand the effects of CA on locomotor output, here we investigated the idiosyncratic features of the spatiotemporal structure of leg muscle activity and impairments in the biomechanics of CA gait. To this end, we recorded the electromyographic (EMG) activity of 12 unilateral lower limb muscles and analyzed kinematic and kinetic parameters of 19 ataxic patients and 20 age-matched healthy subjects during overground walking. Neuromuscular control of gait in CA was characterized by a considerable widening of EMG bursts and significant temporal shifts in the center of activity due to overall enhanced muscle activation between late swing and mid-stance. Patients also demonstrated significant changes in the intersegmental coordination, an abnormal transient in the vertical ground reaction force and instability of limb loading at heel strike. The observed abnormalities in EMG patterns and foot loading correlated with the severity of pathology [International Cooperative Ataxia Rating Scale (ICARS), a clinical ataxia scale] and the changes in the biomechanical output. The findings provide new insights into the physiological role of cerebellum in optimizing the duration of muscle activity bursts and the control of appropriate foot loading during locomotion.
Relationship between individual neuron and network spontaneous activity in developing mouse cortex
Authors: Barnett Heather M. , Gjorgjieva Julijana , Weir Keiko , Comfort Cara , Fairhall Adrienne L. , Moody William J.
Published: September 2014

Spontaneous synchronous activity (SSA) that propagates as electrical waves is found in numerous central nervous system structures and is critical for normal development, but the mechanisms of generation of such activity are not clear. In previous work, we showed that the ventrolateral piriform cortex is uniquely able to initiate SSA in contrast to the dorsal neocortex, which participates in, but does not initiate, SSA (Lischalk JW, Easton CR, Moody WJ. Dev Neurobiol 69: 407–414, 2009). In this study, we used Ca2+ imaging of cultured embryonic day 18 to postnatal day 2 coronal slices (embryonic day 17 + 1–4 days in culture) of the mouse cortex to investigate the different activity patterns of individual neurons in these regions. In the piriform cortex where SSA is initiated, a higher proportion of neurons was active asynchronously between waves, and a larger number of groups of coactive cells was present compared with the dorsal cortex. When we applied GABA and glutamate synaptic antagonists, asynchronous activity and cellular clusters remained, while synchronous activity was eliminated, indicating that asynchronous activity is a result of cell-intrinsic properties that differ between these regions. To test the hypothesis that higher levels of cell-autonomous activity in the piriform cortex underlie its ability to initiate waves, we constructed a conductance-based network model in which three layers differed only in the proportion of neurons able to intrinsically generate bursting behavior. Simulations using this model demonstrated that a gradient of intrinsic excitability was sufficient to produce directionally propagating waves that replicated key experimental features, indicating that the higher level of cell-intrinsic activity in the piriform cortex may provide a substrate for SSA generation.
Synaptic mechanisms underlying interaural level difference selectivity in rat auditory cortex
Authors: Kyweriga Michael , Stewart Whitney , Cahill Carolyn , Wehr Michael
Published: September 2014

The interaural level difference (ILD) is a sound localization cue that is extensively processed in the auditory brain stem and midbrain and is also represented in the auditory cortex. Here, we asked whether neurons in the auditory cortex passively inherit their ILD tuning from subcortical sources or whether their spiking preferences were actively shaped by local inhibition. If inherited, the ILD selectivity of spiking output should match that of excitatory synaptic input. If shaped by local inhibition, by contrast, excitation should be more broadly tuned than spiking output with inhibition suppressing spiking for nonpreferred stimuli. To distinguish between these two processing strategies, we compared spiking responses with excitation and inhibition in the same neurons across a range of ILDs and average binaural sound levels. We found that cells preferring contralateral ILDs (often called EI cells) followed the inheritance strategy. In contrast, cells that were unresponsive to monaural sounds but responded predominantly to near-zero ILDs (PB cells) instead showed evidence of the local processing strategy. These PB cells received excitatory inputs that were similar to those received by the EI cells. However, contralateral monaural sounds and ILDs >0 dB elicited strong inhibition, quenching the spiking output. These results suggest that in the rat auditory cortex, EI cells do not utilize inhibition to shape ILD sensitivity, whereas PB cells do. We conclude that an auditory cortical circuit computes sensitivity for near-zero ILDs.
A functional circuit model of interaural time difference processing
Authors: McColgan Thomas , Shah Sahil , Köppl Christine , Carr Catherine , Wagner Hermann
Published: September 2014

Inputs from the two sides of the brain interact to create maps of interaural time difference (ITD) in the nucleus laminaris of birds. How inputs from each side are matched with high temporal precision in ITD-sensitive circuits is unknown, given the differences in input path lengths from each side. To understand this problem in birds, we modeled the geometry of the input axons and their corresponding conduction velocities and latencies. Consistent with existing physiological data, we assumed a common latency up to the border of nucleus laminaris. We analyzed two biological implementations of the model, the single ITD map in chickens and the multiple maps of ITD in barn owls. For binaural inputs, since ipsi- and contralateral initial common latencies were very similar, we could restrict adaptive regulation of conduction velocity to within the nucleus. Other model applications include the simultaneous derivation of multiple conduction velocities from one set of measurements and the demonstration that contours with the same ITD cannot be parallel to the border of nucleus laminaris in the owl. Physiological tests of the predictions of the model demonstrate its validity and robustness. This model may have relevance not only for auditory processing but also for other computational tasks that require adaptive regulation of conduction velocity.
Electrical coupling betweenAplysiabag cell neurons: characterization and role in synchronous firing
Authors: Dargaei Zahra , Colmers Phillip L. W. , Hodgson Heather M. , Magoski Neil S.
Published: September 2014

In neuroendocrine cells, hormone release often requires a collective burst of action potentials synchronized by gap junctions. This is the case for the electrically coupled bag cell neurons in the reproductive system of the marine snail, Aplysia californica. These neuroendocrine cells are found in two clusters, and fire a synchronous burst, called the afterdischarge, resulting in neuropeptide secretion and the triggering of ovulation. However, the physiology and pharmacology of the bag cell neuron electrical synapse are not completely understood. As such, we made dual whole cell recordings from pairs of electrically coupled cultured bag cell neurons. The junctional current was nonrectifying and not influenced by postsynaptic voltage. Furthermore, junctional conductance was voltage independent and, not surprisingly, strongly correlated with coupling coefficient magnitude. The electrical synapse also acted as a low-pass filter, although under certain conditions, electrotonic potentials evoked by presynaptic action potentials could drive postsynaptic spikes. If coupled neurons were stimulated to spike simultaneously, they presented a high degree of action potential synchrony compared with not-coupled neurons. The electrical synapse failed to pass various intracellular dyes, but was permeable to Cs+, and could be inhibited by niflumic acid, meclofenamic acid, or 5-nitro-2-(3-phenylpropylamino)benzoic acid. Finally, extracellular and sharp-electrode recording from the intact bag cell neuron cluster showed that these pharmacological uncouplers disrupted both electrical coupling and afterdischarge generation in situ. Thus electrical synapses promote bag cell neuron firing synchrony and may allow for electrotonic spread of the burst through the network, ultimately contributing to propagation of the species.
Static roll-tilt over 5 minutes locally distorts the internal estimate of direction of gravity
Authors: Tarnutzer A. A. , Bockisch C. J. , Straumann D. , Marti S. , Bertolini G.
Published: September 2014

The subjective visual vertical (SVV) indicates perceived direction of gravity. Even in healthy human subjects, roll angle-dependent misestimations, roll overcompensation (A-effect, head-roll > 60° and <135°) and undercompensation (E-effect, head-roll < 60°), occur. Previously, we demonstrated that, after prolonged roll-tilt, SVV estimates when upright are biased toward the preceding roll position, which indicates that perceived vertical (PV) is shifted by the prior tilt (Tarnutzer AA, Bertolini G, Bockisch CJ, Straumann D, Marti S. PLoS One 8: e78079, 2013). Hypothetically, PV in any roll position could be biased toward the previous roll position. We asked whether such a “global” bias occurs or whether the bias is “local”. The SVV of healthy human subjects ( N = 9) was measured in nine roll positions (−120° to +120°, steps = 30°) after 5 min of roll-tilt in one of two adaptation positions (±90°) and compared with control trials without adaptation. After adapting, adjustments were shifted significantly ( P < 0.05) toward the previous adaptation position for nearby roll-tilted positions (±30°, ±60°) and upright only. We computationally simulated errors based on the sum of a monotonically increasing function (producing roll undercompensation) and a mixture of Gaussian functions (representing roll overcompensation centered around PV). In combination, the pattern of A- and E-effects could be generated. By shifting the function representing local overcompensation toward the adaptation position, the experimental postadaptation data could be fitted successfully. We conclude that prolonged roll-tilt locally distorts PV rather than globally shifting it. Short-term adaptation of roll overcompensation may explain these shifts and could reflect the brain's strategy to optimize SVV estimates around recent roll positions. Thus postural stability can be improved by visually-mediated compensatory responses at any sustained body-roll orientation.
Intelligence moderates reinforcement learning: a mini-review of the neural evidence
Authors: Chen Chong
Published: September 2014

Our understanding of the neural basis of reinforcement learning and intelligence, two key factors contributing to human strivings, has progressed significantly recently. However, the overlap of these two lines of research, namely, how intelligence affects neural responses during reinforcement learning, remains uninvestigated. A mini-review of three existing studies suggests that higher IQ (especially fluid IQ) may enhance the neural signal of positive prediction error in dorsolateral prefrontal cortex, dorsal anterior cingulate cortex, and striatum, several brain substrates of reinforcement learning or intelligence.
A Novel Vision Sensing System for Tomato Quality Detection
Authors: Srivastava Satyam , Boyat Sachin , Sadistap Shashikant
Published: September 2014

Producing tomato is a daunting task as the crop of tomato is exposed to attacks from various microorganisms. The symptoms of the attacks are usually changed in color, bacterial spots, special kind of specks, and sunken areas with concentric rings having different colors on the tomato outer surface. This paper addresses a vision sensing based system for tomato quality inspection. A novel approach has been developed for tomato fruit detection and disease detection. Developed system consists of USB based camera module having 12.0 megapixel interfaced with ARM-9 processor. Zigbee module has been interfaced with developed system for wireless transmission from host system to PC based server for further processing. Algorithm development consists of three major steps, preprocessing steps like noise rejection, segmentation and scaling, classification and recognition, and automatic disease detection and classification. Tomato samples have been collected from local market and data acquisition has been performed for data base preparation and various processing steps. Developed system can detect as well as classify the various diseases in tomato samples. Various pattern recognition and soft computing techniques have been implemented for data analysis as well as different parameters prediction like shelf life of the tomato, quality index based on disease detection and classification, freshness detection, maturity index detection, and different suggestions for detected diseases. Results are validated with aroma sensing technique using commercial Alpha Mos 3000 system. Accuracy has been calculated from extracted results, which is around 92%.
A Simple Method for Establishing AdherentEx VivoExplant Cultures from Human Eye Pathologies for Use in Subsequent Calcium Imaging and Inflammatory Studies
Authors: Andjelic Sofija , Lumi Xhevat , Veréb Zoltán , Josifovska Natasha , Facskó Andrea , Hawlina Marko , Petrovski Goran
Published: September 2014

A novel, simple, and reproducible method for cultivating pathological tissues obtained from human eyes during surgery was developed using viscoelastic material as a tissue adherent to facilitate cell attachment and expansion and calcium imaging of cultured cells challenged by mechanical and acetylcholine (ACh) stimulation as well as inflammatory studies. Anterior lens capsule-lens epithelial cells (aLC-LECs) from cataract surgery and proliferative diabetic retinopathy (PDR) fibrovascular epiretinal membranes (fvERMs) from human eyes were used in the study. We hereby show calcium signaling in aLC-LECs by mechanical and acetylcholine (ACh) stimulation and indicate presence of ACh receptors in these cells. Furthermore, anex vivostudy model was established for measuring the inflammatory response in fvERMs and aLC-LECs upon TNFα treatment.