bluuebunny/crossref_metadata_2025 huggingface dataset:
Urban-rural variation in mortality and hospital admission rates for unintentional injury in Ireland
Authors: Boland M , Staines A , Fitzpatrick P , Scallan E
Published: February 2005

Objective:To explore urban-rural differences in the mortality and hospital admission rates for unintentional injuries in the Republic of Ireland.

Design:Standardised mortality ratios (SMRs) in residents of urban and non-city areas (called rural areas) from all causes of unintentional injury were calculated using Central Statistics Office mortality data from 1980–2000. Hospital admission data (Hospital In-Patient Enquiry) from 1993–2000 were used to calculate standardised hospital admission ratios (SARs) in urban and rural residents. Population data were obtained from the 1981, 1986, 1991, and 1996 censuses.

Results:The rate of unintentional injury mortality was significantly higher in rural residents for all-cause unintentional injury mortality (SMR 103.0, 95% confidence interval 101 to 105), and specifically for deaths related to motor vehicle trauma (MVT), drowning, machinery, and firearms. There were significantly higher SMRs in urban residents for falls and poisoning. The rate of unintentional injury hospital admission was significantly higher in rural residents for all-cause unintentional injury (SAR 104.6, 95% confidence interval 104 to 105) and specifically for injuries from falls, MVT, being struck by or against an object, injuries in pedal cyclists, fire/burn injuries, and machinery injuries. SARs were significantly higher in residents of urban areas for poisoning and injuries in pedestrians.

Conclusions:There are urban-rural differences in mortality and admissions for injuries in Ireland. Possible reasons for the higher rural mortality rates are higher case fatality in MVT and rural exposure to hazardous farm machinery, firearms, and open areas of water. This information could assist in targeting prevention programmes under the proposed National Injury Prevention Strategy.
Fatal motor vehicle crashes in rural and urban areas: decomposing rates into contributing factors
Authors: Zwerling C , Peek-Asa C , Whitten P S , Choi S-W , Sprince N L , Jones M P
Published: February 2005

Objectives:Motor vehicle crash fatality rates have been consistently higher in rural areas than in urban areas. However, the explanations for these differences are less clear. In this study the decomposition method was used to explore the factors associated with increased fatal crash involvement rates in rural communities.

Design:Using national databases, the fatal crash incidence density was decomposed into the product of three factors: the injury fatality rate, the crash injury rate, and the crash incidence density.

Results:As expected, the fatal crash incidence density was more than two times higher in rural than in urban areas. This was driven primarily by the injury fatality rate, which was almost three times higher in rural areas.

Conclusions:Further research should examine the relative roles of crash severity and the timely receipt of definitive medical care after a crash.
Teen drivers and the risk of injury to child passengers in motor vehicle crashes
Authors: Chen I G , Elliott M R , Durbin D R , Winston F K
Published: February 2005

Objectives:The first aim was to examine the relationship between driver’s age (novice teens, older teens, and adults) and child passenger’s restraint status, front row seating, and injury risk. The second aim was to explore whether there was an excess injury risk to child passengers in teen crashes compared to those in adult crashes by examining the contributing factors.

Methods:A cross sectional study involving telephone interviews with insured drivers in a probability sample of 12 163 crashes involving 19 111 children was conducted. Sequential logistic regressions were employed.

Results:Among child passengers aged 4–8, appropriate restraint was <1% for novice teens, 4.5% for older teens, and 23.6% for adults. Front row seating for children <13 years was more common in the novice teen group (26.8%) than in the other two groups. Compared with children riding with adults, those with both teen groups experienced excess injury risk. After adjusting for crash severity, there was a 43% reduction in the odds ratio (OR) for novice teens (OR 1.58, 95% confidence interval (CI) 1.14 to 2.19) and a 24% reduction for older teens (OR 2.15, 95% CI 1.42 to 3.26). After adjusting for vehicle type, child’s restraint status and front row seating, there was a further 19% reduction in the OR for novice teens (OR 1.37, 95% CI 1.00 to 1.88) and a further 13% reduction for older teens (OR 1.74, 95% CI 1.14 to 2.66).

Conclusion:These findings suggest ways in which graduated driver licensing laws may be further enhanced to better protect child passengers from the excess injury risk associated with teen crashes.
AN APPROACH TO CASE-BASED MAINTENANCE: SELECTING REPRESENTATIVE CASES
Authors: TSANG E. C. C. , WANG X. Z.
Published: February 2005

Case-based maintenance is an important issue in Case-Based Reasoning (CBR) System. Generally speaking, the larger the case-base, the more accurate the solution. However, if the case base is too large, it may include many redundant cases and the case retrieve will not be effective. Moreover redundant cases will affect the solution accuracy. Therefore, removing redundant cases is a fundamental issue in maintaining CBR systems. In this paper, a new approach based on the Generalization Capability of cases to select the representative cases for Case-Based Maintenance is proposed. Using this method, most redundant cases can be deleted and the most representative cases can be identified and retained. The experiments show that the proposed method can greatly remove the redundant cases as well as preserve a satisfying degree of accuracy of solutions when it is used for classification tasks.
A FIRST ORDER PREDICATE LOGIC FORMULATION OF THE 3D RECONSTRUCTION PROBLEM AND ITS SOLUTION SPACE
Authors: ROBINSON MARTIN , KUBIK KURT , LOVELL BRIAN
Published: February 2005

This paper defines the 3D reconstruction problem as the process of reconstructing a 3D scene from numerous 2D visual images of that scene. It is well known that this problem is ill-posed, and numerous constraints and assumptions are used in 3D reconstruction algorithms in order to reduce the solution space. Unfortunately, most constraints only work in a certain range of situations and often constraints are built into the most fundamental methods (e.g. Area Based Matching assumes that all the pixels in the window belong to the same object). This paper presents a novel formulation of the 3D reconstruction problem, using a voxel framework and first order logic equations, which does not contain any additional constraints or assumptions. Solving this formulation for a set of input images gives all the possible solutions for that set, rather than picking a solution that is deemed most likely. Using this formulation, this paper studies the problem of uniqueness in 3D reconstruction and how the solution space changes for different configurations of input images. It is found that it is not possible to guarantee a unique solution, no matter how many images are taken of the scene, their orientation or even how much color variation is in the scene itself. Results of using the formulation to reconstruct a few small voxel spaces are also presented. They show that the number of solutions is extremely large for even very small voxel spaces (5 × 5 voxel space gives 10 to 107 solutions). This shows the need for constraints to reduce the solution space to a reasonable size. Finally, it is noted that because of the discrete nature of the formulation, the solution space size can be easily calculated, making the formulation a useful tool to numerically evaluate the usefulness of any constraints that are added.
k-OUT-OF-n SYSTEM WITH SELF-LOOP UNITS
Authors: JENAB K. , DHILLON B. S.
Published: February 2005

This paper presents an analytical approach for a k-out-of-n system with units having the failure detection, isolation, and recovery mechanisms. The approach uses the flow-graph concept and moment generating function (MGF) to analyze the reliability of the k-out-of-n system with self-loop units. This newly developed analytical approach provides the probability of system failure, system mean, and standard deviation time to failure. A solved example is presented to demonstrate the application of the approach.
OPTIMAL PERIODIC REPLACEMENT POLICY WITH CHECKING TIME
Authors: SHEU SHEY-HUEI , CHEN YAN-CHUN , TENG LI-HSIU
Published: February 2005

This investigation considers a generalized inspection policy for a deteriorating production system with general random minimal repair costs. The inspection times for the inspection strategy are assumed to be non-negligible. Additionally, uncertainty probabilities associated with inspections are introduced. Using a dynamic programming formulation, the optimal inspection time for maximizing profit per unit time for a given overhaul/replacement time is determined. Next, the procedure is extended to determine the optimal periodic overhaul/replacement time, as well as the optimal number of inspections and their schedule.
SHOCK FILTER-BASED DIFFUSION FIELDS — APPLICATION TO GRAYSCALE CHARACTER IMAGE PROCESSING
Authors: CHERIET MOHAMED , DEMERS JEAN-CHRISTOPHE , DEBLOIS SYLVAIN
Published: February 2005

In this article, the new concept of diffusion fields based on partial differential equations is applied to character image processing. Specific diffusion fields are developed according to character image structures and features, depending, on the scope of application. Doing so allows the application of a straightforward one-dimensional numerical scheme to image enhancement, erosion, dilation and thinning. The strength of this approach is the flexibility brought by the diffusion field, which can be defined taking into account specific difficulties of grayscale character images with a minimum of prior information. Thus, the application of the algorithm is shown to be robust to singularity points, the creation of spurious branches, variations in stroke thickness and intensity, multimodality, noise and image background patterns. The resulting enhanced images are noise free with sharp edges and the local typical intensity levels preserved. Thinned characters are connected skeletons located on the ridge of the initial character. Again, the typical intensity of the character and background are preserved.
DOCUMENT IMAGE BINARIZATION WITH FEEDBACK FOR IMPROVING CHARACTER SEGMENTATION
Authors: CHI ZHERU , WANG QING
Published: February 2005

Binarization of gray scale document images is one of the most important steps in automatic document image processing. In this paper, we present a two-stage document image binarization approach, which includes a top-down region-based binarization at the first stage and a neural network based binarization technique for the problematic blocks at the second stage after a feedback checking. Our two-stage approach is particularly effective for binarizing text images of highlighted or marked text. The region-based binarization method is fast and suitable for processing large document images. However, the block effect and regional edge noise are two unavoidable problems resulting in poor character segmentation and recognition. The neural network based classifier can achieve good performance in two-class classification problem such as the binarization of gray level document images. However, it is computationally costly. In our two-stage binarization approach, the feedback criteria are employed to keep the well binarized blocks from the first stage binarization and to re-binarize the problematic blocks at the second stage using the neural network binarizer to improve the character segmentation quality. Experimental results on a number of document images show that our two-stage binarization approach performs better than the single-stage binarization techniques tested in terms of character segmentation quality and computational cost.
DISTORTION REMOVAL FOR CAMERA-IMAGED PRINT MATERIALS USING BOUNDARY INTERPOLATION
Authors: BROWN MICHAEL S. , TSOI YAU-CHAT
Published: February 2005

Camera-based imaging is used to digitize printed materials whose shape and size are not suitable for flatbed and Xerox scanning. Because these materials are not physically pressed flat before imaging, the resulting imaged content often appears distorted due to the material's underlying shape. We present a novel approach to correct common image distortions that arise in camera-imaged printed materials. Our approach uses the boundary information of the imaged material to compute a corrective warp to undo the distortion. Our algorithm is unique in that it simultaneously corrects for a variety of distortions including skew, binder curl, and distortions from folds. In addition, 2.5D information about the boundary can be incorporated to compensate for depth distortion.
SHAPE FROM TEXTURE: LOCAL SCALES AND VANISHING LINE COMPUTATION TO IMPROVE RESULTS FOR MACROTEXTURES
Authors: LELANDAIS S. , BOUTTE L. , PLANTIER J.
Published: February 2005

The aim of "Shape From Texture (SFT)" methods is to obtain three dimensional information out of the monocular view of a scene. In this article, we detail a 2-step SFT computational method. A new local scales extraction technique is used in the first step to compute the local scale of each point of the picture through an interpolation of wavelet values. In the second step, the interpolation of the local scales map helps get a hold of the textured plane's orientation, using the perspective projection model. This method, which is an improvement over Lu's, was tested on synthetic and real textures. Results obtained were consistently better, notably in the case of small slant angles. We also improved the orientation computation by using the vanishing line equation for macrotextures.
HUMAN POSTURE RECONSTRUCTION AND ANIMATION FROM MONOCULAR IMAGES BASED ON GENETIC ALGORITHMS
Authors: ZHAO JIANHUI , LI LING , KEONG KWOH CHEE
Published: February 2005

The paper aims to propose a new approach towards human posture reconstruction and animation from monocular video sequences that contain any kind of human postures and movements. This is a way towards low cost motion capture and at the same time it avoids many limitations of those classical methods. A parameterized human skeleton model based on anatomy is adopted where the angular constraints are encoded in the joints. Criterion Function is defined to represent the residuals between feature points in the monocular image and the corresponding points resulted from projecting the human model to the projection plane. By transforming each segment of the human model to achieve the minimum value of the Criterion Function, the proper human posture that resembles the one represented by the monocular image can be generated. Different kinds of adjustments are utilized to adjust the body parts into the proper locations and orientations in 3D space without camera calibration. In order to find the optimal solution effectively in a high-dimensional parameter space by considering all the parameters simultaneously, the method of Genetic Algorithms is proposed. A procedure is developed to recover the whole body posture, and then a human animation system is developed to animate a series of human movements from monocular image sequences, during which information between consecutive frames is considered to improve the accuracy. Our technique makes it feasible to reconstruct any possible human postures, and experimental results from many monocular images and video sequences are encouraging.
PROJECTIVE VOLUME RENDERING BY EXCLUDING OCCLUDED VOXELS
Authors: WANG WENCHENG , SUN HANQIU , WU ENHUA
Published: February 2005

In volume rendering, an important issue in acceleration is to reduce the calculations for occluded voxels. Although this issue has been addressed in the ray casting approach, it is difficult to apply the idea to the projection approach due to uncertain termination conditions. In this paper, we propose a new method to effectively address the exclusion problem in the projection approach, so the rendering process can be accelerated without impairing the rendered image quality. In the rendering process, this new method employs the dynamic screen technique to manage the pixels whose accumulated opacity has not reached 1.0. A ray-cast link at each pixel is set up to record the rendered voxels for the corresponding ray cast from the pixel to intersect. According to the rendered voxels covering the pixels whose accumulated opacity value is below 1.0, visible voxels are selected to render from front to back by the neighboring relationship between the rendered voxels and the voxels to be rendered. Thus, the occluded voxels are dynamically excluded from the loading and rendering processes accurately. Our proposed method can be in general applied to both parallel and perspective projections, using regular and irregular volume datasets. Our experimental results showed that the proposed method can significantly accelerate volume rendering if the data volume has a high percentage of occluded voxels. This method can also perform fairly efficiently for the expensive shading calculations if requested in volume rendering.
PHASE DIAGRAM IN THE BONABEAU SOCIAL HIERARCHY MODEL WITH INDIVIDUALLY DIFFERENT ABILITIES
Authors: SCHULZE CHRISTIAN , STAUFFER DIETRICH
Published: February 2005

The 1995 model of Bonabeau et al. is generalized by giving each individual a different ability to win or lose a fight. We also introduce different groups such that the losers of fights between different groups are eliminated. The overall phase diagram for the first-order transition between egalitarian and hierarchical societies does not change much after these generalizations.
SYNCHRONIZING TO PERIODICITY: THE TRANSIENT INFORMATION AND SYNCHRONIZATION TIME OF PERIODIC SEQUENCES
Authors: FELDMAN DAVID P. , CRUTCHFIELD JAMES P.
Published: February 2005

We analyze how difficult it is to synchronize to a periodic sequence whose structure is known, when an observer is initially unaware of the sequence's phase. We examine the transient information T, a recently introduced information-theoretic quantity that measures the uncertainty an observer experiences while synchronizing to a sequence. We also consider the synchronization time τ, which is the average number of measurements required to infer the phase of a periodic signal. We calculate T and τ for all periodic sequences up to and including period 23. We show which sequences of a given period have the maximum and minimum possible T and τ values, develop analytic expressions for the extreme values, and show that in these cases the transient information is the product of the total phase information and the synchronization time. Despite the latter result, our analyses demonstrate that the transient information and synchronization time capture different and complementary structural properties of individual periodic sequences — properties, moreover, that are distinct from source entropy rate and mutual information measures, such as the excess entropy.
NETWORK DEPENDENCE OF STRONG RECIPROCITY
Authors: MENDES R. VILELA
Published: February 2005

Experimental evidence suggests that human decisions involve a mixture of self-interest and internalized social norms which cannot be accounted for by the Nash equilibrium behavior of Homo Economicus. This led to the notion of strong reciprocity (or altruistic punishment) to capture the human trait leading an individual to punish norm violators at a cost to himself. For a population with small autonomous groups with collective monitoring, the interplay of intra- and intergroup dynamics shows this to be an adaptive trait, although not fully invasive of a selfish population. However, the absence of collective monitoring in a larger society changes the evolution dynamics. Clustering seems to be the network parameter that controls maintenance and evolution of the reciprocator trait.
31P-NMR observation of free ADP during fatiguing, repetitive contractions of murine skeletal muscle lacking AK1
Authors: Hancock Chad R. , Brault Jeffrey J. , Wiseman Robert W. , Terjung Ronald L. , Meyer Ronald A.
Published: February 2005

Metabolic control within skeletal muscle is designed to limit ADP accumulation even during conditions where ATP demand is out of balance with ATP synthesis. This is accomplished by the reactions of adenylate kinase (AK; ADP+ADP ↔ AMP+ATP) and AMP deaminase (AMP+H2O → NH3+IMP), which limit ADP accumulation under these conditions. The purpose of this study was to determine whether AK deficiency (AK−/−) would result in sufficient ADP accumulation to be visible using 31P-NMRS during the high energy demands of frequent in situ tetanic contractions. To do this we examined the high-energy phosphates of the gastrocnemius muscle in the knockout mouse with AK1−/− and wild-type (WT) control muscle over the course of 64 rapid (2/s) isometric tetanic contractions. Near-complete depletion of phosphocreatine was apparent after 16 contractions in both groups. By ∼40 contractions, ADP was clearly visible in AK1−/− muscle. This transient concentration of the NMR visible free ADP was estimated to be ∼1.7 mM, and represents the first time free ADP has been directly measured in contracting skeletal muscle. Such an increase in free ADP is severalfold greater than previously thought to occur. This large accumulation of free ADP also represents a significant reduction in energy available from ATP, and has implications on cellular processes that depend on a high yield of energy from ATP such as calcium sequestration. Remarkably, the AK1−/− and WT muscles exhibited similar fatigue profiles. Our findings suggest that skeletal muscle is surprisingly tolerant to a large increase in ADP and by extension, a decline in energy from ATP.
Cholinergically stimulated gastric acid secretion is mediated by M3 and M5 but not M1 muscarinic acetylcholine receptors in mice
Authors: Aihara Takeshi , Nakamura Yusuke , Taketo Makoto M. , Matsui Minoru , Okabe Susumu
Published: February 2005

Muscarinic acetylcholine receptors play an important role in the regulation of gastric acid secretion stimulated by acetylcholine; nonetheless, the precise role of each receptor subtype (M1–M5) remains unclear. This study examined the involvement of M1, M3, and M5 receptors in cholinergic regulation of acid secretion using muscarinic receptor knockout (KO) mice. Gastric acid secretion was measured in both mice subjected to acute gastric fistula production under urethane anesthesia and conscious mice that had previously undergone pylorus ligation. M3 KO mice exhibited impaired gastric acid secretion in response to carbachol. Unexpectedly, M1 KO mice exhibited normal intragastric pH, serum gastrin and mucosal histamine levels, and gastric acid secretion stimulatied by carbachol, histamine, and gastrin. Pirenzepine, known as an M1-receptor antagonist, inhibited carbachol-stimulated gastric acid secretion in a dose-dependent manner in M1 KO mice as well as in wild-type (WT) mice, suggesting that the inhibitory effect of pirenzepine on gastric acid secretion is independent of M1-receptor antagonism. Notably, M5 KO mice exhibited both significantly lower carbachol-stimulated gastric acid secretion and histamine-secretory responses to carbachol compared with WT mice. RT-PCR analysis revealed M5-mRNA expression in the stomach, but not in either the fundic or antral mucosa. Consequently, cholinergic stimulation of gastric acid secretion is clearly mediated by M3 (on parietal cells) and M5 receptors (conceivably in the submucosal plexus), but not M1 receptors.
Heart mitochondrial nitric oxide synthase is upregulated in male rats exposed to high altitude (4,340 m)
Authors: Gonzales Gustavo F. , Chung Francisco A. , Miranda Sara , Valdez Laura B. , Zaobornyj Tamara , Bustamante Juanita , Boveris Alberto
Published: February 2005

Male rats exposed for 21 days to high altitude (4,340 m) responded with arrest of weight gain and increased hematocrit and testosterone levels. High altitude significantly (58%) increased heart mitochondrial nitric oxide (NO) synthase (mtNOS) activity, whereas heart cytosolic endothelial NOS (eNOS) and liver mtNOS were not affected. Western blot analysis found heart mitochondria reacting only with anti-inducible NOS (iNOS) antibodies, whereas the postmitochondrial fraction reacted with anti-iNOS and anti-eNOS antibodies. In vitro-measured NOS activities allowed the estimation of cardiomyocyte capacity for NO production, a value that increased from 57% (sea level) to 79 nmol NO·min−1·g heart−1(4,340 m). The contribution of mtNOS to total cell NO production increased from 62% (sea level) to 71% (4340 m). Heart mtNOS activity showed a linear relationship with hematocrit and a biphasic quadratic association with estradiol and testosterone. Multivariate analysis showed that exposure to high altitude linearly associates with hematocrit and heart mtNOS activity, and that testosterone-to-estradiol ratio and heart weight were not linearly associated with mtNOS activity. We conclude that high altitude triggers a physiological adaptive response that upregulates heart mtNOS activity and is associated in an opposed manner with the serum levels of testosterone and estradiol.
Temporary blockade of contractility during reperfusion elicits a cardioprotective effect of the p38 MAP kinase inhibitor SB-203580
Authors: Sumida Tomohiko , Otani Hajime , Kyoi Shiori , Okada Takayuki , Fujiwara Hiroyoshi , Nakao Yoshihisa , Kido Masakuni , Imamura Hiroji
Published: February 2005

p38 MAP kinase activation is known to be deleterious not only to mitochondria but also to contractile function. Therefore, p38 MAP kinase inhibition therapy represents a promising approach in preventing reperfusion injury in the heart. However, reversal of p38 MAP kinase-mediated contractile dysfunction may disrupt the fragile sarcolemma of ischemic-reperfused myocytes. We, therefore, hypothesized that the beneficial effect of p38 MAP kinase inhibition during reperfusion can be enhanced when contractility is simultaneously blocked. Isolated and perfused rat hearts were paced at 330 rpm and subjected to 20 min of ischemia followed by reperfusion. p38 MAP kinase was activated after ischemia and early during reperfusion (<30 min). Treatment with the p38 MAP kinase inhibitor SB-203580 (10 μM) for 30 min during reperfusion, but not the c-Jun NH2-terminal kinase inhibitor SP-600125 (10 μM), improved contractility but increased creatine kinase release and infarct size. Cotreatment with SB-203580 and the contractile blocker 2,3-butanedione monoxime (BDM, 20 mM) or the ultra-short-acting β-blocker esmorol (0.15 mM) for the first 30 min during reperfusion significantly reduced creatine kinase release and infarct size. In vitro mitochondrial ATP generation and myocardial ATP content were significantly increased in the heart cotreated with SB-203580 and BDM during reperfusion. Dystrophin was translocated from the sarcolemma during ischemia and reperfusion. SB-203580 increased accumulation of Evans blue dye in myocytes depleted of sarcolemmal dystrophin during reperfusion, whereas cotreatment with BDM facilitated restoration of sarcolemmal dystrophin and mitigated sarcolemmal damage after withdrawal of BDM. These results suggest that treatment with SB-203580 during reperfusion aggravates myocyte necrosis but concomitant blockade of contractile force unmasks cardioprotective effects of SB-203580.
Long-Evans and Sprague-Dawley rats exhibit divergent responses to refeeding after caloric restriction
Authors: Evans S. A. , Messina M. M. , Knight W. D. , Parsons A. D. , Overton J. M.
Published: February 2005

Mature male Sprague-Dawley (SD) and Long-Evans (LE) rats were instrumented with telemetry transmitters for measurement of heart rate (HR) and housed in room calorimeters for assessment of food intake and oxygen consumption (V̇o2) at standard laboratory temperatures (23°C) to examine physiological responses to caloric restriction (CR; 60% of baseline ad libitum calories for 2 wk) and refeeding. Ad libitum controls had stable food intake (84–88 kcal/day) and gained weight at rates of 3–4 g/day. Groups from both strains assigned to CR exhibited similar patterns of weight loss and reductions in V̇o2 and HR. Upon refeeding, SD rats exhibited a mild, transient hyperphagic response (1 day) accompanied by sustained suppression of V̇o2 and HR that remained evident 8 days after refeeding. In contrast, LE rats exhibited sustained daily hyperphagia that persisted 8 days after refeeding and was accompanied by a complete restoration of HR and V̇o2. The lower HR and V̇o2 observed during refeeding in SD rats were not due to reduced locomotor activity. The results reveal a strain-dependent divergent response to recovery from CR. We conclude that during recovery from CR, homeostatic stimulation of appetite or suppression of energy expenditure may occur selectively to restore body weight.
Elimination of rat spinal neurons expressing neurokinin 1 receptors reduces bladder overactivity and spinal c-fos expression induced by bladder irritation
Authors: Seki Satoshi , Erickson Kristin A. , Seki Masako , Nishizawa Osamu , Igawa Yasuhiko , Ogawa Teruyuki , de Groat William C. , Chancellor Michael B. , Yoshimura Naoki
Published: February 2005

Substance P (SP) binding to neurokinin 1 receptors (NK1R) in the spinal cord reportedly plays an important role in the micturition reflex as well as in nociceptive responses. We therefore investigated the effect of ablation of NK1R-expressing neurons in the spinal cord using saporin, a ribosome-inactivating protein, conjugated with [Sar9, Met (O2)11]SP, a specific ligand of NK1R (SSP-saporin), on the micturition reflex in rats. In female Sprague-Dawley rats, SSP-saporin (1.0 or 1.5 μM) or saporin (1.5 μM) only was injected through an intrathecal catheter implanted at the L6-S1 level of the spinal cord. Three weeks after intrathecal administration of SSP-saporin, NK1R immunoreactivity in lamina I of the spinal cord was significantly reduced, but cystometric parameters in awake rats were not altered. Instillation of capsaicin (15 μM) into the bladder of normal rats induced bladder overactivity. This response to capsaicin was significantly suppressed in SSP-saporin-treated animals. SSP-saporin treatment also decreased c- fos expression in the dorsal horn of the spinal cord induced by instillation of capsaicin into the bladder. These data indicate that NK1R-expressing neurons in the superficial layer of the dorsal horn play an important role in transmission of nociceptive afferent information from the bladder to induce bladder overactivity and spinal c- fos expression elicited by bladder irritation. Toxin-induced damage of NK1R-expressing neurons in the lumbosacral spinal cord may provide an effective modality for treating overactivity and/or nociceptive responses in the bladder without affecting normal micturition.
Temporal nitric oxide dynamics in the paranasal sinuses during humming
Authors: Menzel Lars , Hess Alexander , Bloch Wilhelm , Michel Olaf , Schuster Klaus-Dieter , Gäbler Ralph , Urban Wolfgang
Published: February 2005

In this study, the temporal shape of voice-induced nitric oxide (NO) signals in exhaled air has been investigated in eight healthy individuals by means of laser magnetic resonance spectroscopy. The results of the experimental part have been compared with calculated signals obtained by using a simple one-compartment model of the paranasal sinuses. In the experimental part, a rapidly increasing NO concentration has been found when the subjects started humming. After reaching a maximum, the emission starts to decrease with the shape of an exponential decay and finally reaches a constant level. The time constant of this decay (NO washout) is 3.0 ± 1.2 s. The peak height of the NO emission during humming increases when the time between two humming processes increases. When no voice-induced NO emission takes place, the NO concentration in the paranasal sinuses rebuilds again to a maximum concentration. The typical time constant for the NO recovery is 4.5 ± 3.2 min. A three-compartment model defining exactly the geometry and anatomy of the paranasal sinuses has been developed that is based on three main assumptions of the NO dynamics: 1) constant NO production of the epithelium in the sinuses; 2) the rate of the chemical reaction of NO with the epithelium of the paranasal sinuses is proportional to the NO concentration; and 3) the emission of NO from the sinuses (volume/s) is proportional to the NO concentration. It is shown that the three-compartment model under the experimental conditions can be reduced to a one-compartment model, which describes the complete temporal behavior of the NO exchange.
Spike-Train Variability of Auditory Neurons In Vivo: Dynamic Responses Follow Predictions From Constant Stimuli
Authors: Schaette Roland , Gollisch Tim , Herz Andreas V. M.
Published: February 2005

Reliable accounts of the variability observed in neural spike trains are a prerequisite for the proper interpretation of neural dynamics and coding principles. Models that accurately describe neural variability over a wide range of stimulation and response patterns are therefore highly desirable, especially if they can explain this variability in terms of basic neural observables and parameters such as firing rate and refractory period. In this work, we analyze the response variability recorded in vivo from locust auditory receptor neurons under acoustic stimulation. In agreement with results from other systems, our data suggest that neural refractoriness has a strong influence on spike-train variability. We therefore explore a stochastic model of spike generation that includes refractoriness through a recovery function. Because our experimental data are consistent with a renewal process, the recovery function can be derived from a single interspike-interval histogram obtained under constant stimulation. The resulting description yields quantitatively accurate predictions of the response variability over the whole range of firing rates for constant-intensity as well as amplitude-modulated sound stimuli. Model parameters obtained from constant stimulation can be used to predict the variability in response to dynamic stimuli. These results demonstrate that key ingredients of the stochastic response dynamics of a sensory neuron are faithfully captured by a simple stochastic model framework.
Possible Effects of Depolarizing GABAA Conductance on the Neuronal Input–Output Relationship: A Modeling Study
Authors: Morita Kenji , Tsumoto Kunichika , Aihara Kazuyuki
Published: February 2005

Recent in vitro experiments revealed that the GABAA reversal potential is about 10 mV higher than the resting potential in mature mammalian neocortical pyramidal cells; thus GABAergic inputs could have facilitatory, rather than inhibitory, effects on action potential generation under certain conditions. However, how the relationship between excitatory input conductances and the output firing rate is modulated by such depolarizing GABAergic inputs under in vivo circumstances has not yet been understood. We examine herewith the input–output relationship in a simple conductance-based model of cortical neurons with the depolarized GABAA reversal potential, and show that a tonic depolarizing GABAergic conductance up to a certain amount does not change the relationship between a tonic glutamatergic driving conductance and the output firing rate, whereas a higher GABAergic conductance prevents spike generation. When the tonic glutamatergic and GABAergic conductances are replaced by in vivo–like highly fluctuating inputs, on the other hand, the effect of depolarizing GABAergic inputs on the input–output relationship critically depends on the degree of coincidence between glutamatergic input events and GABAergic ones. Although a wide range of depolarizing GABAergic inputs hardly changes the firing rate of a neuron driven by noncoincident glutamatergic inputs, a certain range of these inputs considerably decreases the firing rate if a large number of driving glutamatergic inputs are coincident with them. These results raise the possibility that the depolarized GABAA reversal potential is not a paradoxical mystery, but is instead a sophisticated device for discriminative firing rate modulation.
Location and Intensity Discrimination in the Leech Local Bend Response Quantified Using Optic Flow and Principal Components Analysis
Authors: Baca Serapio M. , Thomson Eric E. , Kristan William B.
Published: February 2005

In response to touches to their skin, medicinal leeches shorten their body on the side of the touch. We elicited local bends by delivering precisely controlled pressure stimuli at different locations, intensities, and durations to body-wall preparations. We video-taped the individual responses, quantifying the body-wall displacements over time using a motion-tracking algorithm based on making optic flow estimates between video frames. Using principal components analysis (PCA), we found that one to three principal components fit the behavioral data much better than did previous (cosine) measures. The amplitudes of the principal components (i.e., the principal component scores) nicely discriminated the responses to stimuli both at different locations and of different intensities. Leeches discriminated (i.e., produced distinguishable responses) between touch locations that are approximately a millimeter apart. Their ability to discriminate stimulus intensity depended on stimulus magnitude: discrimination was very acute for weak stimuli and less sensitive for stronger stimuli. In addition, increasing the stimulus duration improved the leech's ability to discriminate between stimulus intensities. Overall, the use of optic flow fields and PCA provide a powerful framework for characterizing the discrimination abilities of the leech local bend response.
Spatial Distribution of Gravity-Dependent Gain Changes in the Vestibuloocular Reflex
Authors: Yakushin Sergei B. , Xiang Yongqing , Raphan Theodore , Cohen Bernard
Published: February 2005

This study determined whether dependence of angular vestibuloocular reflex (aVOR) gain adaptation on gravity is a fundamental property in three dimensions. Horizontal aVOR gains were adaptively increased or decreased in two cynomolgus monkeys in upright, side down, prone, and supine positions, and aVOR gains were tested in darkness by yaw rotation with the head in a wide variety of orientations. Horizontal aVOR gain changes peaked at the head position in which the adaptation took place and gradually decreased as the head moved away from this position in any direction. The gain changes were plotted as a function of head tilt and fit with a sinusoid plus a bias to obtain the gravity-dependent (amplitude) and gravity-independent (bias) components. Peak-to-peak gravity-dependent gain changes in planes containing the position of adaptation and the magnitude of the gravity-independent components were both ∼25%. We assumed that gain changes over three-dimensional space could be described by a sinusoid the amplitude of which also varied sinusoidally. Using gain changes obtained from the head position in which the gains were adapted, a three-dimensional surface was generated that was qualitatively similar to a surface obtained from the experimental data. This extends previous findings on vertical aVOR gain adaptation in one plane and introduces a conceptual framework for understanding plasticity in three dimensions: aVOR gain changes are composed of two components, one of which depends on head position relative to gravity. It is likely that this gravitational dependence optimizes the stability of retinal images during movement in three-dimensional space.
Clinical Applications of Stem Cells for the Heart
Authors: Wollert Kai C. , Drexler Helmut
Published: February 2005

Repair of the heart is an old dream of physicians caring for patients with cardiac disease. Experimental studies suggest that cardiac transfer of stem and progenitor cells can have a favorable impact on tissue perfusion and contractile performance of the injured heart. Some researchers favor stable stem cell engraftment by fusion or transdifferentiation into cardiomyocyte or vascular cell lineages as likely explanations for these beneficial effects. Others have proposed that transient cell retention may be sufficient to promote functional effects, eg, by release of paracrine mediators. Although the mechanistic underpinnings of stem cell therapy are still intensely debated, the concept of cell therapy has already been introduced into the clinical setting, where a flurry of small, mostly uncontrolled trials indicate that stem cell therapy may be feasible in patients. The overall clinical experience also suggests that stem cell therapy can be safely performed, if the right cell type is used in the right clinical setting. Preliminary efficacy data indicate that stem cells have the potential to enhance myocardial perfusion and/or contractile performance in patients with acute myocardial infarction, advanced coronary artery disease, and chronic heart failure. The field now is rapidly moving toward intermediate-size, double-blinded trials to gather more safety and efficacy data. Ultimately, large outcome trials will have to be conducted. We need to proceed cautiously with carefully designed clinical trials and keep in mind that patient safety must remain the key concern. At the same time, continued basic research to elucidate the underlying mechanism of stem cell therapy is clearly needed.
The Combined Effects of Inhibitory and Electrical Synapses in Synchrony
Authors: Pfeuty Benjamin , Mato Germán , Golomb David , Hansel David
Published: February 2005

Recent experimental results have shown that GABAergic interneurons in the central nervous system are frequently connected via electrical synapses. Hence, depending on the area or the subpopulation, interneurons interact via inhibitory synapses or electrical synapses alone or via both types of interactions. The theoretical work presented here addresses the significance of these different modes of interactions for the interneuron networks dynamics. We consider the simplest system in which this issue can be investigated in models or in experiments: a pair of neurons, interacting via electrical synapses, inhibitory synapses, or both, and activated by the injection of a noisy external current. Assuming that the couplings and the noise are weak, we derive an analytical expression relating the cross-correlation (CC) of the activity of the two neurons to the phase response function of the neurons. When electrical and inhibitory interactions are not too strong, they combine their effect in a linear manner. In this regime, the effect of electrical and inhibitory interactions when combined can be deduced knowing the effects of each of the interactions separately. As a consequence, depending on intrinsic neuronal proper-ties, electrical and inhibitory synapses may cooperate, both promoting synchrony, or may compete, with one promoting synchrony while the other impedes it. In contrast, for sufficiently strong couplings, the two types of synapses combine in a nonlinear fashion. Remarkably, we find that in this regime, combining electrical synapses with inhibition ampli-fies synchrony, whereas electrical synapses alone would desynchronize the activity of the neurons. We apply our theory to predict how the shape of the CC of two neurons changes as a function of ionic channel conduc-tances, focusing on the effect of persistent sodium conductance, of the firing rate of the neurons and the nature and the strength of their interac-tions. These predictions may be tested using dynamic clamp techniques.
Memory Capacity of Balanced Networks
Authors: Aviel Yuval , Horn David , Abeles Moshe
Published: February 2005

We study the problem of memory capacity in balanced networks of spiking neurons. Associative memories are represented by either synfire chains (SFC) or Hebbian cell assemblies (HCA). Both can be embedded in these balanced networks by a proper choice of the architecture of the network. The size WE of a pool in an SFC or of an HCA is limited from below and from above by dynamical considerations. Proper scaling of WE by √K, where K is the total excitatory synaptic connectivity, allows us to obtain a uniform description of our system for any given K. Using combinatorial arguments, we derive an upper limit on memory capacity. The capacity allowed by the dynamics of the system, αc, is measured by simulations. For HCA, we obtain αc of order 0.1, and for SFC, we find values of order 0.065.

The capacity can be improved by introducing shadow patterns, inhibitory cell assemblies that are fed by the excitatory assemblies in both memory models. This leads to a doubly balanced network, where, in addition to the usual global balancing of excitation and inhibition, there exists specific balance between the effects of both types of assemblies on the background activity of the network. For each of the memory models and for each network architecture, we obtain an allowed region (phase space) for WE √K in which the model is viable.
Robert Boyle, Georges Pierre des Clozets, and the Asterism: a New Source
Authors: Malcolm Noel
Published: February 2005

In 1677-8 Robert Boyle fell victim to a French confidence trickster, Georges Pierre des Clozets, who claimed to belong to a secret society of alchemists, 'the Asterism'; the leader of the Asterism was described as the 'Patriarch of Antioch', resident in Constantinople. New evidence shows that Georges Pierre had contrived to publish two short articles about this 'Patriarch' in a Dutch newspaper, and that one of these was given to Boyle to corroborate Pierre's claims. These articles provide further information about the nature of Pierre's invention. Most importantly, they show that his 'Patriarch of Antioch' was modelled on, and explicitly connected to, a contemporary alchemist in whom Boyle already had an interest: Francesco Giuseppe Borri.
Taking Democracy to Scale
Authors: Lukensmeyer Carolyn J. , Brigham Steven
Published: February 2005

This article explores the large-scale work of America Speaks in the public sector, engaging citizens in 21st Century Town Meetings in decisions that impact their lives. It first reviews the differences in practicing large group work in broader social systems versus more bounded organizational systems. It also reviews the core dimensions and principles of the America Speaks model followed by an examination of the use of these town meetings in land use planning, resource allocation, and policy formulation projects. Finally, the authors describe America Speaks’sintent to institutionalize the practice of national discussions on critical policy issues and highlight the work of other deliberative democracy practitioners over the past decade locally, regionally, nationally, and abroad.
Continuing Education Credit Article
Authors: Ethier Angela M.
Published: February 2005

A death-related sensory experience (DRSE) is a spiritually transforming experience occurring with the appearance of a messenger beyond the visible observable universe to guide a dying person through the dying process. DRSEs have been reported to occur among those who are dying, most commonly individuals with terminal illness. Known dead family members are most commonly seen, followed by religious beings. Communication takes place between the dying individual and the apparition. Feelings of peace and comfort are reported by the majority of individuals experiencing DRSEs. DRSEs can occur over a period of hours to months before death. They have been referred to as veridical hallucinations, visions of the dying, deathbed visions, and predeath visions. Reported throughout time, among people of all cultures, religions, races, ages, genders, socioeconomic status, and educational levels, DRSEs are intense spiritual experiences. Validating a child’s DRSE provides a way to start a dialogue regarding death. Research is needed to more fully understand DRSEs from the perspective of the dying child.