bluuebunny/crossref_metadata_2025 huggingface dataset:
The NS3 Helicase and NS5B-to-3′X Regions Are Important for Efficient Hepatitis C Virus Strain JFH-1 Replication in Huh7 Cells
Authors: Murayama Asako , Date Tomoko , Morikawa Kenichi , Akazawa Daisuke , Miyamoto Michiko , Kaga Minako , Ishii Koji , Suzuki Tetsuro , Kato Takanobu , Mizokami Masashi , Wakita Takaji
Published: May 2007

The JFH-1 strain of hepatitis C virus (HCV) is a genotype 2a strain that can replicate autonomously in Huh7 cells. The J6 strain is also a genotype 2a strain, but its full genomic RNA does not replicate in Huh7 cells. However, chimeric J6/JFH-1 RNA that has J6 structural-protein-coding regions and JFH-1 nonstructural-protein-coding regions can replicate autonomously and produce infectious HCV particles. In order to determine the mechanisms underlying JFH-1 RNA replication, we constructed various J6/JFH-1 chimeras and tested their RNA replication and virus particle production abilities in Huh7 cells. Via subgenomic-RNA-replication assays, we found that both the JFH-1 NS5B-to-3′X (N5BX) and the NS3 helicase (N3H) regions are important for the replication of the J6CF replicon. We applied these results to full-length genomic RNA replication and analyzed replication using Northern blotting. We found that a chimeric J6 clone with JFH-1 N3H and N5BX could replicate autonomously but that a chimeric J6 clone with only JFH-1 N5BX had no replication ability. Finally, we tested the virus production abilities of these clones and found that a chimeric J6 clone with JFH-1 N3H and N5BX could produce infectious HCV particles. In conclusion, the JFH-1 NS3 helicase and NS5B-to-3′X regions are important for efficient replication and virus particle formation of HCV genotype 2a strains.
Work-organisational and personal factors associated with upper body musculoskeletal disorders among sewing machine operators
Authors: Wang Pin-Chieh , Rempel David M , Harrison Robert J , Chan Jacqueline , Ritz Beate R
Published: May 2007

Objective

: To assess the contribution of work-organisational and personal factors to the prevalence of work-related musculoskeletal disorders (WMSDs) among garment workers in Los Angeles.

Methods

: This is a cross-sectional study of self-reported musculoskeletal symptoms among 520 sewing machine operators from 13 garment industry sewing shops. Detailed information on work-organisational factors, personal factors, and musculoskeletal symptoms were obtained in face-to-face interviews. The outcome of interest, upper body WMSD, was defined as a worker experiencing moderate or severe musculoskeletal pain. Unconditional logistic regression models were adopted to assess the association between both work-organisational factors and personal factors and the prevalence of musculoskeletal pain.

Results

: The prevalence of moderate or severe musculoskeletal pain in the neck/shoulder region was 24% and for distal upper extremity it was 16%. Elevated prevalence of upper body pain was associated with age less than 30 years, female gender, Hispanic ethnicity, being single, having a diagnosis of a MSD or a systemic illness, working more than 10 years as a sewing machine operator, using a single sewing machine, work in large shops, higher work–rest ratios, high physical exertion, high physical isometric loads, high job demand, and low job satisfaction.

Conclusion

: Work-organisational and personal factors were associated with increased prevalence of moderate or severe upper body musculoskeletal pain among garment workers. Owners of sewing companies may be able to reduce or prevent WMSDs among employees by adopting rotations between different types of workstations thus increasing task variety; by either shortening work periods or increasing rest periods to reduce the work–rest ratio; and by improving the work-organisation to control psychosocial stressors. The findings may guide prevention efforts in the garment sector and have important public health implications for this workforce of largely immigrant labourers.
Interventions to prevent back pain and back injury in nurses: a systematic review
Authors: Dawson Anna P , McLennan Skye N , Schiller Stefan D , Jull Gwendolen A , Hodges Paul W , Stewart Simon
Published: May 2007

A systematic literature review was undertaken to assess the effectiveness of interventions that aim to prevent back pain and back injury in nurses. Ten relevant databases were searched; these were examined and reference lists checked. Two reviewers applied selection criteria, assessed methodological quality and extracted data from trials. A qualitative synthesis of evidence was undertaken and sensitivity analyses performed. Eight randomised controlled trials and eight non-randomised controlled trials met eligibility criteria. Overall, study quality was poor, with only one trial classified as high quality. There was no strong evidence regarding the efficacy of any interventions aiming to prevent back pain and injury in nurses. The review identified moderate level evidence from multiple trials that manual handling training in isolation is not effective and multidimensional interventions are effective in preventing back pain and injury in nurses. Single trials provided moderate evidence that stress management programs do not prevent back pain and limited evidence that lumbar supports are effective in preventing back injury in nurses. There is conflicting evidence regarding the efficacy of exercise interventions and the provision of manual handling equipment and training. This review highlights the need for high quality randomised controlled studies to examine the effectiveness of interventions to prevent back pain and injury in nursing populations. Implications for future research are discussed.
ELECTROSTATICS OF NANOWIRES AND NANOTUBES: APPLICATION FOR FIELD–EFFECT DEVICES
Authors: SHIK ALEXANDER , RUDA HARRY E. , ROTKIN SLAVA V.
Published: May 2007

We present a quantum and classical theory of electronic devices with one–dimensional (1D) channels made of a single carbon nanotube or a semiconductor nanowire. An essential component of the device theory is a self–consistent model for electrostatics of 1D systems. It is demonstrated that specific screening properties of 1D wires result in a charge distribution in the channel different from that in bulk devices. The drift–diffusion model has been applied for studying transport in a long channel 1D field–effect transistor. A unified self–consistent description is given for both a semiconductor nanowire and a single–wall nanotube. Within this basic model we analytically calculate equilibrium (at zero current) and quasi–equilibrium (at small current) charge distributions in the channel. Numerical results are presented for arbitrary values of the driving current. General analytic expressions, found for basic device characteristic, differ from equations for a standard bulk three–dimensional field–effect device. The device characteristics are shown to be sensitive to the gate and leads geometry and are analyzed separately for bulk, planar and quasi–1D contacts. The basic model is generalized to take into account external charges which can be polarized and/or moving near the channel. These charges change the self–consistent potential profile in the channel and may show up in device properties, for instance, a hysteresis may develop which can have a memory application.
ON YUKAWA AND MASS TERMS IN NONLINEAR SUPERSYMMETRY EQUIVALENT RENORMALIZABLE THEORY
Authors: SHIMA KAZUNARI , TSUDA MOTOMU
Published: May 2007

We show explicitly in D = 2 that N = 2 nonlinear supersymmetric (SUSY) Volkov–Akulov model is equivalent to a spontaneously broken N = 2 linear SUSY interacting theory containing the ordinary Yukawa interactions and mass terms, which is renormalizable, by using SUSY invariant relations.
THERMODYNAMICS OF PSEUDO-HERMITIAN SYSTEMS IN EQUILIBRIUM
Authors: JAKUBSKÝ VÍT
Published: May 2007

In the study of pseudo(quasi)-hermitian operators, the key role is played by the positive-definite metric operator. It enables physical interpretation of the considered systems. In this paper, we study the pseudo-hermitian systems with constant number of particles in equilibrium. We show that the explicit knowledge of the metric operator is not essential for the study of thermodynamic properties of the system. We introduce a simple example where the physically relevant quantities are derived without explicit calculation of either metric operator or spectrum of the Hamiltonian.
ON (2+2)-DIMENSIONAL SPACE–TIMES, STRINGS AND BLACK HOLES
Authors: CASTRO C. , NIETO J. A.
Published: May 2007

We study black hole-like solutions (space–times with singularities) of Einstein field equations in 3+1 and 2+2 dimensions. We find three different cases associated with hyperbolic homogeneous spaces. In particular, the hyperbolic version of Schwarzschild's solution contains a conical singularity at r = 0 resulting from pinching to zero size r = 0 the throat of the hyperboloid [Formula: see text] and which is quite different from the static spherically symmetric (3+1)-dimensional solution. Static circular symmetric solutions for metrics in 2+2 are found that are singular at ρ = 0 and whose asymptotic ρ→∞ limit leads to a flat (1+2)-dimensional boundary of topology S1× R2. Finally we discuss the (1+1)-dimensional Bars–Witten stringy black hole solution and show how it can be embedded into our (3+1)-dimensional solutions. Black holes in a (2+2)-dimensional "space–time" from the perspective of complex gravity in 1+1 complex dimensions and their quaternionic and octonionic gravity extensions deserve furher investigation. An appendix is included with the most general Schwarzschild-like solutions in D ≥ 4.
GIANT QUASI-ATOMS AND SUPERHEAVY NUCLEI PRODUCED IN DAMPED COLLISIONS OF TRANSACTINIDES
Authors: GREINER WALTER , ZAGREBAEV VALERY
Published: May 2007

Low-energy damped collisions of very heavy nuclei (238 U +238 U , 232 Th +250 Cf and 238 U +248 Cm ) are investigated within the realistic model based on multi-dimensional Langevin equations. Large charge and mass transfer was found in these reactions due to the inverse (anti-symmetrizing) quasi-fission process leading to formation of survived superheavy long-lived neutron-rich nuclei. In many events lifetime of the composite system consisting of two touching nuclei (giant quasi-atoms) turns out to be rather long; sufficient for spontaneous positron formation from a super-strong electric field, a fundamental QED process.
OSCILLONS IN SCALAR FIELD THEORIES: APPLICATIONS IN HIGHER DIMENSIONS AND INFLATION
Authors: GLEISER MARCELO
Published: May 2007

The basic properties of oscillons — localized, long-lived, time-dependent scalar field configurations — are briefly reviewed, including recent results demonstrating how their existence depends on the dimensionality of space–time. Their role on the dynamics of phase transitions is discussed, and it is shown that oscillons may greatly accelerate the decay of metastable vacuum states. This mechanism for vacuum decay — resonant nucleation — is then applied to cosmological inflation. A new inflationary model is proposed which terminates with fast bubble nucleation.
STRANGENESS IN NEUTRON STARS
Authors: WEBER FRIDOLIN , HO ALEXANDER , NEGREIROS RODRIGO P. , ROSENFIELD PHILIP
Published: May 2007

It is generally agreed on that the tremendous densities reached in the centers of neutron stars provide a high-pressure environment in which several intriguing particles processes may compete with each other. These range from the generation of hyperons to quark deconfinement to the formation of kaon condensates and H-matter. There are theoretical suggestions of even more exotic processes inside neutron stars, such as the formation of absolutely stable strange quark matter. In the latter event, neutron stars would be largely composed of strange quark matter possibly enveloped in a thin nuclear crust. This paper gives a brief overview of these striking physical possibilities with an emphasis on the role played by strangeness in neutron star matter, which constitutes compressed baryonic matter at ultra-high baryon number density but low temperature which is not accessible to relativistic heavy ion collision experiments.
PHASE TRANSITION IN STRANGE QUARK MATTER WITH DENSITY DEPENDENT QUARK MASS
Authors: ORSARIA M. , RODRIGUES H. , DUARTE S. B.
Published: May 2007

We investigate the color superconducting phase transition in strange quark matter at zero temperature considering the density dependence of quark masses. At high densities, it is well known that cold quark matter is a color superconductor with favorable phase being the color flavor locked (CFL). We analyze the phase transition between the initially strange quark matter (SQM) and the CFL phases. The quark masses are parametrized with the baryon number density nB in the dense system.
PHASE TRANSITION IN ROTATING NEUTRON STARS
Authors: MARRANGHELLO G. F.
Published: May 2007

We review the properties of a phase transition from hadronic matter to deconfined strange quark matter in the core of neutron stars. The neutron star equation of state is computed using a non-linear field theoretical model and the MIT bag model. Rapidly rotating neutron star configurations are studied and the consequences of the conversion and a subsequently micro-collapse, such as gravitational wave emission and pulsar spin-up, are analyzed.
STABILITY OF NEUTRON STARS WITH A LARGE AMOUNT OF STRANGENESS
Authors: RAZEIRA MOISES , BODMANN BARDO E. J. , VASCONCELLOS CÉSAR A. ZEN , MESQUITA ALEXANDRE
Published: May 2007

We investigate the role of the strange σ* and ϕ meson fields on the delineation of the main properties of neutron stars using a parameterized Lagrangian density model in the effective baryon and meson sectors. We assume strange quarks are localized within the hyperon fields which carry the strangeness content of the model. Our main goal is to analyze stability conditions of neutron stars with a large amount of strangeness per baryon. Our main result indicates the inclusion of the strange meson fields σ* and ϕ into nuclear matter make the equation of state stiffer thereby increasing the gravitational mass of the neutron star.
MESON DECAY IN THE FOCK–TANI FORMALISM
Authors: DA SILVA DANIEL T. , DA SILVA MARIO L. L. , HADJIMICHEF DIMITER , VASCONCELLOS CESAR A. Z.
Published: May 2007

The Fock–Tani formalism is a first principle method to obtain effective interactions from microscopic Hamiltonians. Usually this formalism has been applied to scattering; here we introduce it to calculate partial decay widths for mesons.
Aging impairs neurogenic contraction in guinea pig urinary bladder: role of oxidative stress and melatonin
Authors: Gómez-Pinilla Pedro J. , Pozo Maria J. , Camello Pedro J.
Published: May 2007

The incidence of urinary bladder disturbances increases with age, and free radical accumulation has been proposed as a causal factor. Here we investigated the association between changes in bladder neuromuscular function and oxidative stress in aging and the possible benefits of melatonin treatment. Neuromuscular function was assessed by electrical field stimulation (EFS) of isolated guinea pig detrusor strips from adult and aged female guinea pigs. A group of adult and aged animals were treated with 2.5 mg·kg−1·day−1 melatonin for 28 days. Neurotransmitter blockers were used to dissect pharmacologically the EFS-elicited contractile response. EFS induced a neurogenic and frequency-dependent contraction that was impaired by aging. This impairment is in part related to a decrease in detrusor myogenic contractility. Age also decreased the sensitivity of the contraction to pharmacological blockade of purinergic and sensitive fibers but increased the effect of blockade of nitrergic and adrenergic nerves. The density of cholinergic and nitrergic nerves remained unaltered, but aging modified afferent fibers. These changes were associated with an increased level of markers for oxidative stress. Melatonin treatment normalized oxidative levels and counteracted the aging-associated changes in bladder neuromuscular function. In conclusion, these results show that aging modifies neurogenic contraction and the functional profile of the urinary bladder plexus and simultaneously increases the oxidative damage to the organ. Melatonin reduces oxidative stress and improves the age-induced changes in bladder neuromuscular function, which could be of importance in reducing the impact of age-related bladder disorders.
Tachykinin NK3 receptor contribution to systemic release of vasopressin and oxytocin in response to osmotic and hypotensive challenge
Authors: Haley Gwendolen E. , Flynn Francis W.
Published: May 2007

Activation of the neurokinin 3 receptor (NK3R) by a receptor agonist, hypotension, and hyperosmolarity results in the internalization of NK3R expressed by magnocellular neurons and the release of vasopressin (VP) and oxytocin (OT) into the circulation. The contribution of NK3R activation to the release of VP and OT in response to hyperosmolarity and hypotension was evaluated by measuring the release of both hormones following pretreatment with a selective NK3R antagonist, SB-222200. Freely behaving male rats were given an intraventricular injection of either 0.15 M NaCl or 250, 500, or 1,000 pmol SB-222200, and then were administered an intravenous infusion of 2 M NaCl or 0.15 M NaCl ( experiment 1), or a bolus intra injection of 0.15 M NaCl or hydralazine (HDZ), a hypotension-inducing drug ( experiment 2). Blood samples were taken from indwelling arterial catheters at various time points for 1–2 h, both before and after treatments. Plasma VP and OT levels were determined by ELISA. Blockade of NK3R did not affect the baseline levels of either hormone. In contrast, pretreatment with SB-222200 significantly reduced (∼60%) or abolished the release of VP and OT, respectively, to 2 M NaCl infusion. HDZ-induced VP and OT release was eliminated by pretreatment with 500 pmol SB-222200. Therefore, NK3R activation contributes significantly to the systemic release of both VP and OT in response to osmotic and hypotensive challenges.
Myocardial perfusion during exercise in endurance-trained and untrained humans
Authors: Laaksonen Marko S. , Kalliokoski Kari K. , Luotolahti Matti , Kemppainen Jukka , Teräs Mika , Kyröläinen Heikki , Nuutila Pirjo , Knuuti Juhani
Published: May 2007

Because of technical challenges very little is known about absolute myocardial perfusion in humans in vivo during physical exercise. In the present study we applied positron emission tomography (PET) in order to 1) investigate the effects of dynamic bicycle exercise on myocardial perfusion and 2) clarify the possible effects of endurance training on myocardial perfusion during exercise. Myocardial perfusion was measured in endurance-trained and healthy untrained subjects at rest and during absolutely the same (150 W) and relatively similar [70% maximal power output ( Wmax)] bicycle exercise intensities. On average, the absolute myocardial perfusion was 3.4-fold higher during 150 W ( P < 0.001) and 4.9-fold higher during 70% Wmax( P < 0.001) than at rest. At 150 W myocardial perfusion was 46% lower in endurance-trained than in untrained subjects (1.67 ± 0.45 vs. 3.00 ± 0.75 ml·g−1·min−1; P < 0.05), whereas during 70% Wmaxperfusion was not significantly different between groups ( P = not significant). When myocardial perfusion was normalized with rate-pressure product, the results were similar. Thus, according to the present results, myocardial perfusion increases in parallel with the increase in working intensity and in myocardial work rate. Endurance training seems to affect myocardial blood flow pattern during submaximal exercise and leads to more efficient myocardial pump function.
Endothelial dysfunction and arterial pressure regulation during early diabetes in mice: roles for nitric oxide and endothelium-derived hyperpolarizing factor
Authors: Fitzgerald Sharyn M. , Kemp-Harper Barbara K. , Parkington Helena C. , Head Geoffrey A. , Evans Roger G.
Published: May 2007

We determined whether nitric oxide (NO) counters the development of hypertension at the onset of diabetes in mice, whether this is dependent on endothelial NO synthase (eNOS), and whether non-NO endothelium-dependent vasodilator mechanisms are altered in diabetes in mice. Male mice were instrumented for chronic measurement of mean arterial pressure (MAP). In wild-type mice, MAP was greater after 5 wk of Nω-nitro-l-arginine methyl ester (l-NAME; 100 mg·kg−1·day−1 in drinking water; 97 ± 3 mmHg) than after vehicle treatment (88 ± 3 mmHg). MAP was also elevated in eNOS null mice (113 ± 4 mmHg). Seven days after streptozotocin treatment (200 mg/kg iv) MAP was further increased in l-NAME-treated mice (108 ± 5 mmHg) but not in vehicle-treated mice (88 ± 3 mmHg) nor eNOS null mice (104 ± 3 mmHg). In wild-type mice, maximal vasorelaxation of mesenteric arteries to acetylcholine was not altered by chronic l-NAME or induction of diabetes but was reduced by 42 ± 6% in l-NAME-treated diabetic mice. Furthermore, the relative roles of NO and endothelium-derived hyperpolarizing factor (EDHF) in acetylcholine-induced vasorelaxation were altered; the EDHF component was enhanced by l-NAME and blunted by diabetes. These data suggest that NO protects against the development of hypertension during early-stage diabetes in mice, even in the absence of eNOS. Furthermore, in mesenteric arteries, diabetes is associated with reduced EDHF function, with an apparent compensatory increase in NO function. Thus, prior inhibition of NOS results in endothelial dysfunction in early diabetes, since the diabetes-induced reduction in EDHF function cannot be compensated by increases in NO production.
Are pacemaker properties required for respiratory rhythm generation in adult turtle brain stems in vitro?
Authors: Johnson Stephen M. , Wiegel Liana M. , Majewski David J.
Published: May 2007

The role of pacemaker properties in vertebrate respiratory rhythm generation is not well understood. To address this question from a comparative perspective, brain stems from adult turtles were isolated in vitro, and respiratory motor bursts were recorded on hypoglossal (XII) nerve rootlets. The goal was to test whether burst frequency could be altered by conditions known to alter respiratory pacemaker neuron activity in mammals (e.g., increased bath KCl or blockade of specific inward currents). While bathed in artificial cerebrospinal fluid (aCSF), respiratory burst frequency was not correlated with changes in bath KCl (0.5–10.0 mM). Riluzole (50 μM; persistent Na+channel blocker) increased burst frequency by 31 ± 5% ( P < 0.05) and decreased burst amplitude by 42 ± 4% ( P < 0.05). In contrast, flufenamic acid (FFA, 20–500 μM; Ca2+-activated cation channel blocker) reduced and abolished burst frequency in a dose- and time-dependent manner ( P < 0.05). During synaptic inhibition blockade with bicuculline (50 μM; GABAAchannel blocker) and strychnine (50 μM; glycine receptor blocker), rhythmic motor activity persisted, and burst frequency was directly correlated with extracellular KCl (0.5–10.0 mM; P = 0.005). During synaptic inhibition blockade, riluzole (50 μM) did not alter burst frequency, whereas FFA (100 μM) abolished burst frequency ( P < 0.05). These data are most consistent with the hypothesis that turtle respiratory rhythm generation requires Ca2+-activated cation channels but not pacemaker neurons, which thereby favors the group-pacemaker model. During synaptic inhibition blockade, however, the rhythm generator appears to be transformed into a pacemaker-driven network that requires Ca2+-activated cation channels.
Effects on protein kinase C-β inhibition on glomerular vascular endothelial growth factor expression and endothelial cells in advanced experimental diabetic nephropathy
Authors: Kelly Darren J. , Buck Danielle , Cox Alison J. , Zhang Yuan , Gilbert Richard E.
Published: May 2007

Ruboxistaurin is an inhibitor of the β isoform of protein kinase C (PKC-β) that reduces the actions of vascular endothelial growth factor (VEGF) and attenuates the progression of diabetic retinopathy. In the glomerulus VEGF is constitutively expressed where it likely has a role in maintaining endothelial cell integrity, particularly in disease states. Given its potential use in diabetic nephropathy, we sought to determine the effects of PKC-β inhibition on VEGF and glomerular endothelial cells in experimental diabetic nephropathy. Studies were conducted in (mRen-2)27 rat, a transgenic rodent with hypertension and an enhanced renin-angiotensin system that following induction of diabetes with streptozotocin develops many of the features of diabetic nephropathy. Moreover, to mimic the clinical context, the effects of PKC-β inhibition were examined both with and without concomitant angiotensin-converting enzyme (ACE) inhibitor therapy. Diabetic Ren-2 rats were randomized to receive either vehicle, the ACE inhibitor, perindopril (0.2 mg/l in drinking water), ruboxistaurin (10 mg·kg−1·day−1, admixed in chow), or their combination and studied for 12 wk. Diabetic Ren-2 rats displayed glomerular endothelial cell loss in association with overexpression of VEGF mRNA. Both cell loss and VEGF overexpression were attenuated by the administration of either perindopril or ruboxistaurin, as single agent treatments with their combination providing additional, incremental improvements, reducing these manifestations of injury down to levels seen in nondiabetic, normotensive, nontransgenic animals. Combination therapy was also associated with additional improvements in albuminuria and glomerulosclerosis.
Evidence for gut factor in K+ homeostasis
Authors: Lee Felix N. , Oh Gisuk , McDonough Alicia A. , Youn Jang H.
Published: May 2007

We tested the hypothesis that K+ intake is sensed by putative K+ sensors in the splanchnic areas, and renal K+ handling is regulated by this signal. K+ was infused for 2 h into overnight-fasted rats via the jugular vein (systemic infusion), hepatic portal vein (intraportal infusion), or stomach (intragastric infusion) ( n = 5 each), and plasma K+ concentration ([K+]) and renal K+ excretion were measured during the 2-h preinfusion, 2-h K+ infusion, and 3-h washout periods. During systemic K+ infusion, plasma [K+] increased by ∼1.3 mM ( P < 0.05), and, on cessation of the K+ infusion, plasma [K+] fell to the preinfusion level within 1–2 h. Renal K+ excretion changed in proportion to the changes in plasma [K+]. During intraportal or intragastric K+ infusion, plasma [K+] and renal K+ excretion profiles were similar to those with systemic infusion. The effects of K+ infusions via the different routes ( n = 5 or 6 each) were also studied during simultaneous feeding of overnight-fasted rats with a K+-deficient diet. During the meal, intraportal infusion resulted in increases in plasma [K+] similar to those with the systemic K+ infusion, while intragastric K+ infusion did not significantly increase plasma [K+]. Thus, when the intragastric K+ infusion was combined with a meal, there was marked enhancement of clearance of the K+ infused, which was associated with an apparent increase in renal efficiency of K+ excretion. These data suggest that there may be a gut factor that enhances renal efficiency of K+ excretion during meal (or dietary K+) intake.
Circuit Motifs for Spatial Orientation Behaviors Identified by Neural Network Optimization
Authors: Dunn N. A. , Conery J. S. , Lockery S. R.
Published: May 2007

Spatial orientation behavior is universal among animals, but its neuronal basis is poorly understood. The main objective of the present study was to identify candidate patterns of neuronal connectivity (motifs) for two widely recognized classes of spatial orientation behaviors: hill climbing, in which the organism seeks the highest point in a spatial gradient, and goal seeking, in which the organism seeks an intermediate point in the gradient. Focusing on simple networks of graded processing neurons characteristic of Caenorhabditis elegans and other nematodes, we used an unbiased optimization algorithm to seek values of neuronal time constants, resting potentials, and synaptic strengths sufficient for each type of behavior. We found many different hill-climbing and goal-seeking networks that performed equally well in the two tasks. Surprisingly, however, each hill-climbing network represented one of just three fundamental circuit motifs, and each goal-seeking network comprised two of these motifs acting in concert. These motifs are likely to inform the search for the real circuits that underlie these behaviors in nematodes and other organisms.
EEG Sharp Waves and Sparse Ensemble Unit Activity in the Macaque Hippocampus
Authors: Skaggs William E. , McNaughton Bruce L. , Permenter Michele , Archibeque Matthew , Vogt Julie , Amaral David G. , Barnes Carol A.
Published: May 2007

Neural unit activity and EEGs were recorded from inferior temporal regions of three rhesus macaques chronically implanted with “hyperdrives” holding 12 individually movable tetrodes. Recordings were made from each monkey over a period of ∼3 mo, while the electrodes were moved by small increments through the hippocampus and neighboring structures. After recording, the monkeys were necropsied, and the brains were sectioned and Nissl-stained, permitting identification of individual electrode tracks. The results establish that hippocampal pyramidal cells are “complex spike cells,” firing at overall average rates of ∼0.3 Hz, with spike trains consisting of long periods of silence interspersed with bursts of activity. The results also establish that the monkey hippocampal EEG shows “sharp wave” events consisting of a high-frequency “ripple” oscillation (∼110 Hz) together with a large slow-wave EEG deflection lasting several hundred milliseconds. The evidence suggests that monkey sharp waves are probably generated mainly in the CA1 region and that sharp waves are associated with an inactive/drowsy-or-sleeping behavioral state, which is also associated with increased hippocampal pyramidal cell activity and increased hippocampal EEG amplitude. The results of this initial study of ensembles of primate hippocampal neurons are consistent with previous studies in rodents and consistent with the hypothesis that theories and models of hippocampal memory function developed on the basis of rat data may be applicable to a wide range of mammalian species.
Interspike Interval Analysis of Retinal Ganglion Cell Receptive Fields
Authors: Rathbun Daniel L. , Alitto Henry J. , Weyand Theodore G. , Usrey W. Martin
Published: May 2007

The interspike interval (ISI) preceding a retinal spike has a strong influence on whether retinal spikes will drive postsynaptic responses in the lateral geniculate nucleus (LGN). This ISI-based filtering of retinal spikes could, in principle, be used as a mechanism for processing visual information en route from retina to cortex; however, this form of processing has not been previously explored. Using a white noise stimulus and reverse correlation analysis, we compared the receptive fields associated with retinal spikes over a range of ISIs (0–120 ms). Results showed that, although the location and sign of retinal ganglion cell receptive fields are invariant to ISI, the size and amplitude of receptive fields vary with ISI. These results support the notion that ISI-based filtering of retinal spikes can serve as a mechanism for shaping receptive fields.
Serum High-Density Lipoprotein Cholesterol and Risk of Non-Hodgkin Lymphoma
Authors: Lim Unhee , Gayles Travis , Katki Hormuzd A. , Stolzenberg-Solomon Rachael , Weinstein Stephanie J. , Pietinen Pirjo , Taylor Philip R. , Virtamo Jarmo , Albanes Demetrius
Published: May 2007

Lymphoma patients often exhibit abnormal lipid metabolism. Recent evidence, however, suggests that a decrease in circulating high-density lipoprotein cholesterol (HDL-C) may occur during lymphomagenesis, reflecting underlying etiology such as inflammation. We investigated the relationship between prediagnostic HDL-C and non-Hodgkin lymphoma (NHL) in the Alpha-Tocopherol Beta-Carotene Cancer Prevention Study cohort. At baseline, serum HDL-C and total cholesterol concentrations from fasting blood, information on diet and lifestyle, and direct measurements of height, weight, and blood pressure were obtained from 27,074 healthy male smokers of ages 50 to 69 years. Cox proportional hazards models with age as underlying time metric was used to estimate relative risks (RR) and 95% confidence intervals (95% CI). We found no association between total or non-HDL cholesterol and the 201 incident NHL cases ascertained during the follow-up (1985–2002), but observed an inverse association between HDL-C and NHL, which changed with length of follow-up. High HDL-C was associated with lower risk of all NHL during the first 10 years (n = 148; RR for 5th versus 1st quintile, 0.35; 95% CI, 0.19–0.62; Ptrend < 0.0001), but not with diagnoses during later follow-up (n = 53; RR, 1.31; 95% CI, 0.55–3.10). The inverse association was similar for NHL subtypes and was not modified by obesity, blood pressure, physical activity, or alcohol intake, but seemed to be stronger in men with lower duration of smoking (Pinteraction = 0.06). Our findings implicate HDL-C as a preclinical indicator of NHL and warrant further prospective investigations for its etiologic contribution. [Cancer Res 2007;67(11):5569–74]
Generation of Synthetic Spike Trains with Defined Pairwise Correlations
Authors: Niebur Ernst
Published: May 2007

Recent technological advances as well as progress in theoretical understanding of neural systems have created a need for synthetic spike trains with controlled mean rate and pairwise cross-correlation. This report introduces and analyzes a novel algorithm for the generation of discretized spike trains with arbitrary mean rates and controlled cross correlation. Pairs of spike trains with any pairwise correlation can be generated, and higher-order correlations are compatible with common synaptic input. Relations between allowable mean rates and correlations within a population are discussed. The algorithm is highly efficient, its complexity increasing linearly with the number of spike trains generated and therefore inversely with the number of cross-correlated pairs.
Extracting Number-Selective Responses from Coherent Oscillations in a Computer Model
Authors: Miller Jeremy A. , Kenyon Garrett T.
Published: May 2007

Cortical neurons selective for numerosity may underlie an innate number sense in both animals and humans. We hypothesize that the number- selective responses of cortical neurons may in part be extracted from coherent, object-specific oscillations . Here, indirect evidence for this hypothesis is obtained by analyzing the numerosity information encoded by coherent oscillations in artificially generated spikes trains. Several experiments report that gamma-band oscillations evoked by the same object remain coherent, whereas oscillations evoked by separate objects are uncorrelated. Because the oscillations arising from separate objects would add in random phase to the total power summed across all stimulated neurons, we postulated that the total gamma activity, normalized by the number of spikes, should fall roughly as the square root of the number of objects in the scene, thereby implicitly encoding numerosity. To test the hypothesis, we examined the normalized gamma activity in multiunit spike trains, 50 to 1000 msec in duration, produced by a model feedback circuit previously shown to generate realistic coherent oscillations. In response to images containing different numbers of objects, regardless of their shape, size, or shading, the normalized gamma activity followed a square-root-of-n rule as long as the separation between objects was sufficiently large and their relative size and contrast differences were not too great. Arrays of winner-take-all numerosity detectors, each responding to normalized gamma activity within a particular band, exhibited tuning curves consistent with behavioral data. We conclude that coherent oscillations in principle could contribute to the number-selective responses of cortical neurons, although many critical issues await experimental resolution.
Misinterpretations of the “Cone of Uncertainty” in Florida during the 2004 Hurricane Season
Authors: Broad Kenneth , Leiserowitz Anthony , Weinkle Jessica , Steketee Marissa
Published: May 2007

This article reviews the evolution, communication, and differing interpretations of the National Hurricane Center's “cone of uncertainty” hurricane forecast graphic. It concludes with a discussion of this graphic from the perspective of risk communication theory. The 2004 hurricane season, in which five named storms struck Florida, demonstrated that hurricane forecast graphics, despite admirable attempts by the forecast community to make user-friendly products, are still subject to misinterpretation by many members of the public. This exploratory analysis draws upon interviews with key government officials and media figures, archival research of Florida newspapers, analysis of 962 public comments on the National Hurricane Center's cone of uncertainty graphic, a separate multiagency study of2004 hurricane behavior, and relevant risk communication literature, to identify several characteristics of this graphic that likely contribute to public misinterpretation. Forecast providers should consider more formal, rigorous pretesting of forecast graphics, using standard social science techniques, in order to minimize the probability of misinterpretation.
Enhancing Water Cycle Measurements for Future Hydrologic Research
Authors: Loescher H. W. , Jacobs J. M. , Wendroth O. , Robinson D. A. , Poulos G. S. , McGuire K. , Reed P. , Mohanty B. P. , Shanley J. B. , Krajewski W.
Published: May 2007

The Consortium of Universities for the Advancement of Hydrologic Sciences, Inc., established the Hydrologic Measurement Facility to transform watershed-scale hydrologic research by facilitating access to advanced instrumentation and expertise that would not otherwise be available to individual investigators. We outline a committee-based process that determined which suites of instrumentation best fit the needs of the hydrological science community and a proposed mechanism for the governance and distribution of these sensors. Here, we also focus on how these proposed suites of instrumentation can be used to address key scientific challenges, including scaling water cycle science in time and space, broadening the scope of individual subdisciplines of water cycle science, and developing mechanistic linkages among these subdisciplines and spatiotemporal scales.
Transnational Political Alliances
Authors: Kennedy Scott
Published: May 2007

This article draws attention to an understudied phenomenon, transnational political alliances (TPA), which occur when multinational corporations cooperate with local companies to influence public policies of the host government. The article first explores the economic and political sources of TPAs, their structures, and the obstacles to their formation. It then examines TPAs in the context of China, a critical case because of the hostile political environment that discourages TPAs. However, the surprisingly common occurrence of TPAs in China indicates the power of economic incentives for political cooperation yet also suggests the need for further studies of TPAs in a wide variety of economic and political settings.
Monsters and angels
Authors: Wardle Claire
Published: May 2007

The crime of child murder is considered the most heinous and least comprehensible of all violent crimes. This study examines the visual representation of 12 high profile child abductions and murders in broadsheet and tabloid newspapers from two countries over a 70-year time frame. The body of coverage produced almost 1000 images and these were examined using a content analysis of the individual subjects of these photographs, followed by a qualitative analysis of the main patterns which emerged. The study produced two expected findings: that the coverage has become increasingly visual, and that the visuals were overwhelmingly `personal'. Within these overarching patterns, it was clear that the content of the visuals has changed over the three decades studied (the 1930s, 1960s and 1990s). In the earlier decades the visuals emphasized the role of the criminal justice system in capturing the perpetrators and bringing them to justice. In the 1990s there was a far greater focus on the victims' families, as well as the emotional responses of society as a whole: both grief for the child, and anger towards their killers and the authorities which `enabled' them to offend. I explore these changes and the possible impact this visual coverage could have on public understanding of this crime, those who commit it, and how we treat them.
Human multipotent mesenchymal stromal cells inhibit proliferation of PBMCs independently of IFNγR1 signaling and IDO expression
Authors: Gieseke Friederike , Schütt Burkhardt , Viebahn Susanne , Koscielniak Ewa , Friedrich Wilhelm , Handgretinger Rupert , Müller Ingo
Published: May 2007

Multipotent mesenchymal stromal cells (MSCs) inhibit proliferation, helper, and effector functions in most if not all peripheral blood mononuclear cell (PBMC) subpopulations in vitro. The molecular mechanism is widely thought to imply tryptophan degradation by the interferon-γ (IFNγ)–induced expression of indoleamine 2,3-dioxygenase (IDO). However, IDO inhibitors were not able to restore proliferation of PBMCs in each case. Moreover, human MSCs with an IFNγ receptor 1 (R1) defect inhibited proliferation of HLA-mismatched PBMCs to a similar extent as control MSCs. In contrast to healthy MSCs, IFNγR1-deficient MSCs showed no detectable mRNA for IDO—neither in the absence nor in the presence of recombinant human IFNγ, nor in coculture with HLA-mismatched PBMCs. Based on gene expression profiling, we were able to show that insulin-like growth factor (IGF)–binding proteins contribute to the inhibitory mechanism of MSCs. Taken together, human MSCs exert important immunomodulatory functions in the absence of IFNγR1 signaling and IDO, partially accounted for by IGF-binding proteins.
Expression of nitric oxide synthase isoforms in the dorsal horn of monoarthritic rats: effects of competitive and uncompetitive N-methyl-D-aspartate antagonists
Authors: Infante Claudio , Díaz Marcelo , Hernández Alejandro , Constandil Luis , Pelissier Teresa
Published: May 2007

Chronic pain is associated withN-methyl-D-aspartate (NMDA) receptor activation and downstream production of nitric oxide, which has a pivotal role in multisynaptic local circuit nociceptive processing in the spinal cord. The formation of nitric oxide is catalyzed by three major nitric oxide synthase (NOS) isoforms (neuronal, nNOS; inducible, iNOS; endothelial, eNOS), which are increased in the spinal cord of rodents subjected to some tonic and chronic forms of experimental pain. Despite the important role of NOS in spinal cord nociceptive transmission, there have been no studies exploring the effect of NMDA receptor blockade on NOS expression in the dorsal horn during chronic pain. Furthermore, NOS isoforms have not been fully characterized in the dorsal horn of animals subjected to arthritic pain. The aim of this work was therefore to study the expression of nNOS, iNOS and eNOS in the dorsal horns of monoarthritic rats, and the modifications in NOS expression induced by pharmacological blockade of spinal cord NMDA receptors. Monoarthritis was produced by intra-articular injection of complete Freund's adjuvant into the right tibio-tarsal joint. At week 4, monoarthritic rats were given either the competitive NMDA antagonist (±)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) or the uncompetitive NMDA antagonist ketamine. After 6 and 24 hours, animals were killed and posterior quadrants of the lumbar spinal cord were dissected. Sample tissues were homogenized and subjected to immunoblotting with anti-nNOS, anti-iNOS or anti-eNOS monoclonal antibodies. The nNOS isoform, but not the iNOS and eNOS isoforms, were detected in the dorsal horns of control rats. Monoarthritis increased the expression of nNOS, iNOS and eNOS in the dorsal horns ipsilateral and contralateral to the inflamed hindpaw. Intrathecal administration of CPP and ketamine reduced nNOS expression in monoarthritic rats but increased the expression of iNOS and eNOS. Results suggest that blockade of spinal cord NMDA receptors produces complex regulatory changes in the expression of NOS isoforms in monoarthritic rats that may be relevant for nitridergic neuronal/glial mechanisms involved in the pathophysiology of monoarthritis and in the pharmacological response to drugs interacting with NMDA receptors.
Changes in retinoic acid signaling alter otic patterning
Authors: Hans Stefan , Westerfield Monte
Published: May 2007

Retinoic acid (RA) has pleiotropic functions during embryogenesis. In zebrafish, increasing or blocking RA signaling results in enlarged or reduced otic vesicles, respectively. Here we elucidate the mechanisms that underlie these changes and show that they have origins in different tissues. Excess RA leads to ectopic foxi1 expression throughout the entire preplacodal domain. Foxi1 provides competence to adopt an otic fate. Subsequently, pax8, the expression of which depends upon Foxi1 and Fgf, is also expressed throughout the preplacodal domain. By contrast, loss of RA signaling does not affect foxi1 expression or otic competence, but instead results in delayed onset of fgf3 expression and impaired otic induction. fgf8 mutants depleted of RA signaling produce few otic cells, and these cells fail to form a vesicle, indicating that Fgf8 is the primary factor responsible for otic induction in RA-depleted embryos. Otic induction is rescued by fgf8 overexpression in RA-depleted embryos,although otic vesicles never achieve a normal size, suggesting that an additional factor is required to maintain otic fate. fgf3;tcf2 double mutants form otic vesicles similar to RA-signaling-depleted embryos,suggesting a signal from rhombomere 5-6 may also be required for otic fate maintenance. We show that rhombomere 5 wnt8b expression is absent in both RA-signaling-depleted embryos and in fgf3;tcf2 double mutants,and inactivation of wnt8b in fgf3 mutants by morpholino injection results in small otic vesicles, similar to RA depletion in wild type. Thus, excess RA expands otic competence, whereas the loss of RA impairs the expression of fgf3 and wnt8b in the hindbrain,compromising the induction and maintenance of otic fate.
Evolution of the dorsal-ventral patterning network in the mosquito,Anopheles gambiae
Authors: Goltsev Yury , Fuse Naoyuki , Frasch Manfred , Zinzen Robert P. , Lanzaro Gregory , Levine Mike
Published: May 2007

The dorsal-ventral patterning of the Drosophila embryo is controlled by a well-defined gene regulation network. We wish to understand how changes in this network produce evolutionary diversity in insect gastrulation. The present study focuses on the dorsal ectoderm in two highly divergent dipterans, the fruitfly Drosophila melanogaster and the mosquito Anopheles gambiae. In D. melanogaster, the dorsal midline of the dorsal ectoderm forms a single extra-embryonic membrane, the amnioserosa. In A. gambiae, an expanded domain forms two distinct extra-embryonic tissues, the amnion and serosa. The analysis of approximately 20 different dorsal-ventral patterning genes suggests that the initial specification of the mesoderm and ventral neurogenic ectoderm is highly conserved in flies and mosquitoes. By contrast, there are numerous differences in the expression profiles of genes active in the dorsal ectoderm. Most notably, the subdivision of the extra-embryonic domain into separate amnion and serosa lineages in A. gambiae correlates with novel patterns of gene expression for several segmentation repressors. Moreover, the expanded amnion and serosa anlage correlates with a broader domain of Dpp signaling as compared with the D. melanogaster embryo. Evidence is presented that this expanded signaling is due to altered expression of the soggene.
Zur Geschichte der Interpunktionskonzeptionen des Deutschen – dargestellt an der Kodifizierung des Punktes / On the history of the conception of punctuation in German - a description exemplified by the codification of the full stop
Authors: Bredel Ursula
Published: May 2007

This paper deals with the historical development of theories of German punctuation from the 15