Home About us Contact
|
Home About us Contact | ||
|
|
||
Passive
Terms modified by Passive Selected AbstractsPassive Versus Active Parental Permission: Implications for the Ability of School-Based Depression Screening to Reach Youth at RiskJOURNAL OF SCHOOL HEALTH, Issue 3 2008March 2008 issue of Journal of School Health No abstract is available for this article. [source] The Effect of Ovariectomy and Estrogen on Penetrating Brain Arterioles and Blood-Brain Barrier PermeabilityMICROCIRCULATION, Issue 8 2009Marilyn J. Cipolla ABSTRACT Objective: We investigated the effect of estrogen replacement on the structure and function of penetrating brain arterioles (PA) and blood-brain barrier (BBB) permeability. Materials and Methods: Female ovariectomized Sprague-Dawley rats were replaced with estradiol (E2) and estriol (E3) (OVX + E;N=13) and compared to ovariectomized animals without replacement (OVX; N=14) and intact controls (CTL, proestrous; N=13). Passive and active diameters, percent tone, and passive distensibility of pressurized PA were compared. In addition, BBB permeability to Lucifer Yellow, a marker of transcellular transport, was compared in cerebral arteries. Results: Ovariectomy increased myogenic tone in PA, compared to CTL, that was not ameliorated by estrogen treatment. Percent tone at 75 mmHg for CTL vs. OVX and OVX + E was 44±3% vs. 51±1% and 54±3% (P<0.01 vs. CTL for both). No differences were found in passive diameters or distensibility between the groups. BBB permeability increased 500% in OVX vs. CTL animals; however, estrogen replacement restored barrier properties: flux of Lucifer Yellow for CTL, OVX, and OVX + E was (ng/mL): 3.4±1.2, 20.2±5.3 (P<0.01 vs. CTL), and 6.15±1.2 (n.s.). Conclusions: These results suggest that estrogen replacement may not be beneficial for small-vessel disease in the brain, but may limit BBB disruption and edema under conditions that cause it. [source] Omalizumab decreases nonspecific airway hyperresponsiveness in vitroALLERGY, Issue 2 2007P. Berger Background:, In asthmatic patients, both symptoms and hyperresponsiveness are related to immunoglobulin E (IgE) concentration in serum. The anti-IgE monoclonal antibody omalizumab improved the control of asthma, but its effect on airway hyperresponsiveness is controversial. Passive sensitization reproduced in vitro a bronchial hyperresponsiveness, an increase in IgE bearing cells, and a mast cell degranulation. This study was designed to examine the effect of omalizumab on passive sensitization-induced hyperresponsiveness, alterations in IgE positive inflammatory cells and mast cell degranulation within the bronchial wall. Methods:, Proximal (3,5 mm diameter) and distal (0.5,1.5 mm diameter) human bronchi dissected out from 10 lung specimens were incubated in normal or asthmatic serum containing various concentrations of omalizumab. Contractile responses to histamine or Dermatophagoides pteronyssinus (D. pter) were recorded using an organ bath system and expressed as percentage of maximal contractile response to acetylcholine (ACh). Immunohistochemistry was performed using monoclonal antibodies directed against IgE or tryptase. Mast cells were classified as fully granulated (type I), partly (type II) or largely degranulated (type III). Results:, The specific bronchial hyperresponsiveness to D. pter and the nonspecific bronchial hyperresponsiveness to histamine following passive sensitization were significantly inhibited by omalizumab in both distal and proximal airways. Passive sensitization-induced increase in IgE positive cells was also abolished by omalizumab in a concentration dependent manner. Mast cell degranulation which was inhibited by omalizumab was positively correlated with the contractile response to D. pter. Conclusions:, Omalizumab blocks specific and nonspecific bronchial hyperresponsiveness. Anti-IgE also decreases IgE bearing cell number and mast cell degranulation. [source] Sampling systems for isotope-ratio mass spectrometry of atmospheric ammoniaRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 2 2006Richard Skinner Passive and active ammonia (NH3) sampling devices have been tested for their nitrogen (N) capture potential and ,15N fractionation effects. Several sampling techniques produced significantly different ,15NH3 signals when sampling the same NH3 source released from field site fumigation campaigns. Conventional passive NH3 -monitoring systems have shown to provide insufficient N for isotope-ratio mass spectrometry and various modified devices have been developed, based on existing diffusion tube designs, to overcome this problem. The final sampler design was then tested in a wind tunnel to verify that sampling NH3 in different environmental conditions did not significantly fractionate the ,15N signal. Copyright © 2005 John Wiley & Sons, Ltd. [source] A modelling study of locomotion-induced hyperpolarization of voltage threshold in cat lumbar motoneuronesTHE JOURNAL OF PHYSIOLOGY, Issue 2 2002Yue Dai During fictive locomotion the excitability of adult cat lumbar motoneurones is increased by a reduction (a mean hyperpolarization of ,6.0 mV) of voltage threshold (Vth) for action potential (AP) initiation that is accompanied by only small changes in AP height and width. Further examination of the experimental data in the present study confirms that Vth lowering is present to a similar degree in both the hyperpolarized and depolarized portions of the locomotor step cycle. This indicates that Vth reduction is a modulation of motoneurone membrane currents throughout the locomotor state rather than being related to the phasic synaptic input within the locomotor cycle. Potential ionic mechanisms of this locomotor-state-dependent increase in excitability were examined using three five-compartment models of the motoneurone innervating slow, fast fatigue resistant and fast fatigable muscle fibres. Passive and active membrane conductances were set to produce input resistance, rheobase, afterhyperpolarization (AHP) and membrane time constant values similar to those measured in adult cat motoneurones in non-locomoting conditions. The parameters of 10 membrane conductances were then individually altered in an attempt to replicate the hyperpolarization of Vth that occurs in decerebrate cats during fictive locomotion. The goal was to find conductance changes that could produce a greater than 3 mV hyperpolarization of Vth with only small changes in AP height (< 3 mV) and width (< 1.2 ms). Vth reduction without large changes in AP shape could be produced either by increasing fast sodium current or by reducing delayed rectifier potassium current. The most effective Vth reductions were achieved by either increasing the conductance of fast sodium channels or by hyperpolarizing the voltage dependency of their activation. These changes were particularly effective when localized to the initial segment. Reducing the conductance of delayed rectifier channels or depolarizing their activation produced similar but smaller changes in Vth. Changes in current underlying the AHP, the persistent Na+ current, three Ca2+ currents, the ,h' mixed cation current, the ,A' potassium current and the leak current were either ineffective in reducing Vth or also produced gross changes in the AP. It is suggested that the increased excitability of motoneurones during locomotion could be readily accomplished by hyperpolarizing the voltage dependency of fast sodium channels in the axon hillock by a hitherto unknown neuromodulatory action. [source] A Study on the Mixing Behavior of Different Density Liquids in a Stirred Tank Reactor by Passive and Reactive TracersCHEMIE-INGENIEUR-TECHNIK (CIT), Issue 8 2005G. Hessel Dipl.-Phys. No abstract is available for this article. [source] Hybrid Control of Smart Structures Using a Novel Wavelet-Based AlgorithmCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 1 2005Hongjin Kim A new hybrid control system is presented through judicious combination of a passive supplementary damping system with a semi-active TLCD system. The new model utilizes the advantages of both passive and semi-active control systems, thereby improving the overall performance, reliability, and operability of the control system during normal operations as well as a power or computer failure. The robust wavelet-hybrid feedback least mean square (LMS) control algorithm developed recently by the authors is used to find optimal values of the control parameters. The effectiveness and robustness of the proposed hybrid damper-TLCD system in reducing the vibrations under various seismic excitations are evaluated through numerical simulations performed for an eight-story frame using three different simulated earthquake ground accelerations. It is found that the new model is effective in significantly reducing the response of the structure under various seismic excitations. [source] Cardiovascular function in the heat-stressed humanACTA PHYSIOLOGICA, Issue 4 2010C. G. Crandall Abstract Heat stress, whether passive (i.e. exposure to elevated environmental temperatures) or via exercise, results in pronounced cardiovascular adjustments that are necessary for adequate temperature regulation as well as perfusion of the exercising muscle, heart and brain. The available data suggest that generally during passive heat stress baroreflex control of heart rate and sympathetic nerve activity are unchanged, while baroreflex control of systemic vascular resistance may be impaired perhaps due to attenuated vasoconstrictor responsiveness of the cutaneous circulation. Heat stress improves left ventricular systolic function, evidenced by increased cardiac contractility, thereby maintaining stroke volume despite large reductions in ventricular filling pressures. Heat stress-induced reductions in cerebral perfusion likely contribute to the recognized effect of this thermal condition in reducing orthostatic tolerance, although the mechanism(s) by which this occurs is not completely understood. The combination of intense whole-body exercise and environmental heat stress or dehydration-induced hyperthermia results in significant cardiovascular strain prior to exhaustion, which is characterized by reductions in cardiac output, stroke volume, arterial pressure and blood flow to the brain, skin and exercising muscle. These alterations in cardiovascular function and regulation late in heat stress/dehydration exercise might involve the interplay of both local and central reflexes, the contribution of which is presently unresolved. [source] Confronting Uncertainty and Missing Values in Environmental Value Transfer as Applied to Species ConservationCONSERVATION BIOLOGY, Issue 5 2010SONIA AKTER conservación de especies; error de transferencia; incertidumbre; transferencia de valor ambiental; valores de no uso Abstract:,The nonuse (or passive) value of nature is important but time-consuming and costly to quantify with direct surveys. In the absence of estimates of these values, there will likely be less investment in conservation actions that generate substantial nonuse benefits, such as conservation of native species. To help overcome decisions about the allocation of conservation dollars that reflect the lack of estimates of nonuse values, these values can be estimated indirectly by environmental value transfer (EVT). EVT uses existing data or information from a study site such that the estimated monetary value of an environmental good is transferred to another location or policy site. A major challenge in the use of EVT is the uncertainty about the sign and size of the error (i.e., the percentage by which transferred value exceeds the actual value) that results from transferring direct estimates of nonuse values from a study to a policy site, the site where the value is transferred. An EVT is most useful if the decision-making framework does not require highly accurate information and when the conservation decision is constrained by time and financial resources. To account for uncertainty in the decision-making process, a decision heuristic that guides the decision process and illustrates the possible decision branches, can be followed. To account for the uncertainty associated with the transfer of values from one site to another, we developed a risk and simulation approach that uses Monte Carlo simulations to evaluate the net benefits of conservation investments and takes into account different possible distributions of transfer error. This method does not reduce transfer error, but it provides a way to account for the effect of transfer error in conservation decision making. Our risk and simulation approach and decision-based framework on when to use EVT offer better-informed decision making in conservation. Resumen:,El valor de no uso (o pasivo) de la naturaleza es importante pero su cuantificación con muestreos pasivos consume tiempo y es costosa. En ausencia de estimaciones de estos valores, es probable que haya menos inversión en acciones de conservación que generen beneficios de no uso sustanciales, tal como la conservación de especies nativas. Para ayudar a superar decisiones respecto a la asignación de dólares para conservación que reflejan la carencia de estimaciones de los valores de no uso, estos valores pueden ser estimados indirectamente por la transferencia de valor ambiental (TVA). La transferencia de valor ambiental utiliza datos existentes o información de un sitio de estudio de tal manera que el valor monetario estimado de un bien ambiental es transferido a otro sitio. Un reto mayor en el uso de TVA es la incertidumbre sobre la señal y el tamaño del error (i.e., el porcentaje en que el valor transferido excede al valor actual) que resulta de la transferencia de estimaciones directas de los valores de no uso de un sitio de estudio a uno político, el sitio adonde el valor es transferido. Una TVA es más útil si el marco de toma de decisiones no requiere información muy precisa y cuando la decisión de conservación está restringida por tiempo y recursos financieros. Para tomar en cuenta la incertidumbre en el proceso de toma de decisiones, se puede seguir una decisión heurística que guie el proceso de decisión e ilustre sobre las posibles ramificaciones de la decisión. Para tomar en cuenta la incertidumbre asociada con la transferencia de valores de un sitio a otro, desarrollamos un método de riesgo y simulación que utiliza simulaciones Monte Carlo para evaluar los beneficios netos de las inversiones de conservación y que considera posibles distribuciones diferentes de la transferencia de error. Este método no reduce el error de transferencia, pero proporciona una manera para considerar el efecto del error de transferencia en la toma de decisiones de conservación. Nuestro método de riesgo y simulación y el marco de referencia basado en decisones sobre cuando utilizar TVA permiten la toma de decisiones en conservación más informadas. [source] Motor impairments in young children with cerebral palsy: relationship to gross motor function and everyday activitiesDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 9 2004Sigrid Østensjø MSc PT In this study we assessed the distribution of spasticity, range of motion (ROM) deficits, and selective motor control problems in children with cerebral palsy (CP), and examined how these impairments relate to each other and to gross motor function and everyday activities. Ninety-five children (55 males, 40 females; mean age 58 months, SD18 months, range 25 to 87 months) were evaluated with the modified Ashworth scale (MAS), passive ROM, the Selective Motor Control scale (SMC), the Gross Motor Function Measure (GMFM), and the Pediatric Evaluation of Disability Inventory (PEDI). Types of CP were hemiplegia (n=19), spastic diplegia (n=40), ataxic diplegia (n=4), spastic quadriplegia (n=16), dyskinetic (n=9), and mixed type (n=7). Severity spanned all five levels of the Gross Motor Function Classification System (GMFCS). The findings highlight the importance of measuring spasticity and ROM in several muscles and across joints. Wide variability of correlations of MAS, ROM, and SMC indicates a complex relationship between spasticity, ROM, and selective motor control. Loss of selective control seemed to interfere with gross motor function more than the other impairments. Further analyses showed that motor impairments were only one component among many factors that could predict gross motor function and everyday activities. Accomplishment of these activities was best predicted by the child's ability to perform gross motor tasks. [source] Electrophysiological and morphological characterization of dentate astrocytes in the hippocampusDEVELOPMENTAL NEUROBIOLOGY, Issue 2 2005Masako Isokawa Abstract We studied electrophysiological and morphological properties of astrocytes in the dentate gyrus of the rat hippocampus in slices. Intracellular application of Lucifer yellow revealed two types of morphology: one with a long process extruding from the cell body, and the other with numerous short processes surrounding the cell body. Their electrophysiological properties were either passive, that is, no detectable voltage-dependent conductance, or complex, with Na+/K+ currents similar to those reported in the Ammon's horn astrocytes. We did not find any morphological correlate to the types of electrophysiological profile or dye coupling. Chelation of cytoplasmic calcium ([Ca2+]i) by BAPTA increased the incidence of detecting a low Na+ conductance and transient outward K+ currents. However, an inwardly rectifying K+ current (Kir), a hallmark of differentiated CA1/3 astrocytes, was not a representative K+ -current in the complex dentate astrocytes, suggesting that these astrocytes could retain an immature form of K-currents. Dentate astrocytes may possess a distinct current profile that is different from those in CA1/3 Ammon's horn. © 2005 Wiley Periodicals, Inc. J Neurobiol, 2005 [source] Alpha-melanocyte-stimulating hormone attenuates behavioral effects of corticotropin-releasing factor in isolated guinea pig pupsDEVELOPMENTAL PSYCHOBIOLOGY, Issue 5 2009Patricia A. Schiml-Webb Abstract During a 3-hr period of social isolation in a novel environment, guinea pig pups exhibit an initial active phase of behavioral responsiveness, characterized primarily by vocalizing, which is then followed by a stage of passive responsiveness in which pups display a distinctive crouch, eye-closing, and extensive piloerection. Prior treatment of pups with alpha-melanocyte-stimulating hormone (,-MSH) reduces each of the passive behaviors. The onset of passive responding during separation can be accelerated with peripheral injection of corticotropin-releasing factor (CRF). To examine whether CRF produces its effects through a mechanism similar to that of prolonged separation, we examined the effect of administering ,-MSH to pups injected with CRF. As expected, CRF markedly enhanced passive responding during a 60-min period of separation. ,-MSH delivered by either intracerebroventricular infusion or intraperitoneal injection significantly reduced each of the passive behavioral responses without significantly affecting active behavior. These findings, together with previous results indicating that it is the anti-inflammatory property of ,-MSH that is responsible for its behavioral effects during prolonged separation, suggest that peripheral CRF speeds the induction of passive responding through a mechanism involving enhanced proinflammatory activity. © 2009 Wiley Periodicals, Inc. Dev Psychobiol 51: 399,407, 2009. [source] Understanding and beliefs of diabetes in the UK Bangladeshi populationDIABETIC MEDICINE, Issue 6 2009S. M. Choudhury Abstract Aims, To examine the understanding and beliefs of people with diabetes from the Bangladeshi community living in the UK. Methods, Structured interviews were carried out with 14 people invited to a peer educational programme. All interviews were on a one-to-one basis and were in Sylheti or in English. Interviews were transcribed and analysed by two independent researchers. Results, The majority of participants did not know what caused diabetes. Knowledge of the management of diabetes was linked to controlling sugar intake and a number of participants reported eating bitter foods such as bitter gourd to control their diabetes. There was little access to information as many participants did not speak English and did not have a Bengali-speaking doctor. The majority of participants felt that education classes should teach them what the doctor thought was important and that these classes would best be advertised by word of mouth. Therefore, participants were quite passive about their own self management and relied very strongly on the doctor's views and recommendations. Conclusions, Findings from this study can be used to help health professionals working with Bangladeshi people. There is a need for improved information for Bangladeshi people and much of this information might need to come from health professionals. In addition, there is a need for increased awareness by health professionals of practices used by Bangladeshi people, such as eating bitter gourd (which may enhance the effects of rosiglitazone), and the influence these practices could have on the individual's diabetes management. [source] Sensitivity of seismically isolated structuresEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 8 2009Ioannis Politopoulos Abstract In this paper we study the sensitivity of seismically isolated structures to a small variability of the earthquake excitation and of some structural properties with respect to the probability of failure and floor spectra. In particular, the influence of the nonlinear behaviour of the isolated superstructure on the vulnerability and on the floor spectra is investigated by means of a series of Monte Carlo simulations of simple two degrees-of-freedom systems. Several types of passive and active isolation systems are examined and three different idealized nonlinear constitutive laws are considered for the superstructure. It is found that, in general, the probability of failure does not depend on the specific cyclic behaviour of the assumed constitutive law and general trends regarding the impact of different isolation devices on vulnerability are established. As for the floor spectra, the influence of moderate nonlinear behaviour of isolated superstructures, with the exception of the case of a non-dissipative elastic nonlinear law, is negligible, contrary to the case of conventional structures. Copyright © 2008 John Wiley & Sons, Ltd. [source] Experimental performance evaluation of an equipment isolation using MR dampersEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 3 2009Yu-Cheng Fan Abstract Critical non-structural equipments, including life-saving equipment in hospitals, circuit breakers, computers, high technology instrumentations, etc., are vulnerable to strong earthquakes, and the failure of these equipments may result in a heavy economic loss. In this connection, innovative control systems and strategies are needed for their seismic protections. This paper presents the performance evaluation of passive and semi-active control in the equipment isolation system for earthquake protection. Through shaking table tests of a 3-story steel frame with equipment on the first floor, a magnetorheological (MR)-damper together with a sliding friction pendulum isolation system is placed between the equipment and floor to reduce the vibration of the equipment. Various control algorithms are used for this semi-active control studies, including the decentralized sliding mode control (DSMC) and LQR control. The passive-on and passive-off control of MR damper is used as a reference for the discussion on the control effectiveness. Copyright © 2008 John Wiley & Sons, Ltd. [source] Shaking table tests on reinforced concrete frames without and with passive control systemsEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 14 2005Mauro Dolce Abstract An extensive experimental program of shaking table tests on reduced-scale structural models was carried out within the activities of the MANSIDE project, for the development of new seismic isolation and energy dissipation devices based on shape memory alloys (SMAs). The aim of the experimental program was to compare the behaviour of structures endowed with innovative SMA-based devices to the behaviour of conventional structures and of structures endowed with currently used passive control systems. This paper presents a comprehensive overview of the main results of the shaking table tests carried out on the models with and without special braces. Two different types of energy dissipating and re-centring braces have been considered to enhance the seismic performances of the tested model. They are based on the hysteretic properties of steel elements and on the superelastic properties of SMAs, respectively. The addition of passive control braces in the reinforced concrete frame resulted in significant benefits on the overall seismic behaviour. The seismic intensity producing structural collapse was considerably raised, interstorey drifts and shear forces in columns were drastically reduced. Copyright © 2005 John Wiley & Sons, Ltd. [source] Frequency domain modal analysis of earthquake input energy to highly damped passive control structuresEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 5 2004Izuru Takewaki Abstract A new complex modal analysis-based method is developed in the frequency domain for efficient computation of the earthquake input energy to a highly damped linear elastic passive control structure. The input energy to the structure during an earthquake is an important measure of seismic demand. Because of generality and applicability to non-linear structures, the earthquake input energy has usually been computed in the time domain. It is shown here that the formulation of the earthquake input energy in the frequency domain is essential for deriving a bound on the earthquake input energy for a class of ground motions and for understanding the robustness of passively controlled structures to disturbances with various frequency contents. From the viewpoint of computational efficiency, a modal analysis-based method is developed. The importance of overdamped modes in the energy computation of specific non-proportionally damped models is demonstrated by comparing the energy transfer functions and the displacement transfer functions. Through numerical examinations for four recorded ground motions, it is shown that the modal analysis-based method in the frequency domain is very efficient in the computation of the earthquake input energy. Copyright © 2004 John Wiley & Sons, Ltd. [source] Hybrid platform for vibration control of high-tech equipment in buildings subject to ground motion.EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 8 2003Part 2: analysis Abstract The experimental results of using a hybrid platform to mitigate vibration of a batch of high-tech equipment installed in a building subject to nearby traffic-induced ground motion have been presented and discussed in the companion paper. Based on the identified dynamic properties of both the building and the platform, this paper first establishes an analytical model for hybrid control of the building-platform system subject to ground motion in terms of the absolute co-ordinate to facilitate the absolute velocity feedback control strategy used in the experiment. The traffic-induced ground motion used in the experiment is then employed as input to the analytical model to compute the dynamic response of the building-platform system. The computed results are compared with the measured results, and the comparison is found to be satisfactory. Based on the verified analytical model, coupling effects between the building and platform are then investigated. A parametric study is finally conducted to further assess the performance of both passive and hybrid platforms at microvibration level. The analytical study shows that the dynamic interaction between the building and platform should be taken into consideration. The hybrid control is effective in reducing both velocity response and drift of the platform/high-tech equipment at microvibration level with reasonable control force. Copyright © 2003 John Wiley & Sons, Ltd. [source] Illumination influences the ability of migrating juvenile salmonids to pass a submerged experimental weirECOLOGY OF FRESHWATER FISH, Issue 2 2009P. S. Kemp Abstract,,, The downstream migration of juvenile salmonids has previously been considered predominantly passive. It has been argued that passive displacement during periods of darkness is, partially at least, a result of an inability to maintain a fixed position in the absence of visual cues. In this study, behaviour of juvenile Pacific salmonids was assessed under conditions of light and dark as they passed through an artificial channel and encountered a submerged weir. Results indicated that when light, fish formed schools and actively explored the channel. Conversely, when dark (infrared illumination only) they did not form schools, but maintained randomly distributed positions holding station against the flow. As a consequence, more fish approached and either passed, or rejected, the weir when light. The majority of fish that passed the weir did so within the first minute of each trial. Fish predominantly passed through the channel facing downstream and changed orientation prior to passing tail first over the weir crest in the presence and absence of visual cues. The orientation switch was less common when dark. This study shows, at a fine-resolution scale, that downstream movement of juvenile salmonids can be inhibited as fish exhibit alternative behaviours in the absence of visual cues. Downstream movement was not predominantly passive. Fish passage design should not be based on the assumption that downstream migration is passive. [source] Quantitative evaluation of sample application methods for semipreparative separations of basic proteins by two-dimensional gel electrophoresisELECTROPHORESIS, Issue 19-20 2003Richard C. Barry Abstract The use of cup-loading for sample application has become widely used in two-dimensional electrophoresis (2-DE) for resolution of basic proteins, but no side-by-side quantitative study has been published which compares cup-loading with the alternative passive and active rehydration methods to fully promote one type of loading method over another. Replicate 2-D gels from each loading method were quantitatively evaluated for gel-to-gel reproducibility using IPG 6,11 strips and semipreparative protein loads (300 ,g). Gels were stained with SYPRO Ruby and analyzed with PDQuest. An inexpensive home-made assembly for cup-loading was used with the Protean IEF Cell for separation of whole cell extracts from the archaeon, Sulfolobus solfataricus. Cup-loading was determined to be far superior for IPG 6,11 separations than active or passive rehydration methods. Cup-loading consistently produced the greatest number of detectable spots, the best spot matching efficiency (56%), lowest spot quantity variations (28% coefficient of variation, CV), and the best-looking gels qualitatively. The least satisfactory results were obtained with active rehydration, followed closely by passive rehydration in off-line tubes. Passive rehydration experiments, performed using an on-line isoelectric focusing (IEF) tray, produced comparable spot numbers to cup-loading (84%), with 55% of the spots having higher intensity but 10% more spot quantity variance than cup-loading. [source] A Bridge Too Far?ENGLISH IN EDUCATION, Issue 2 2001Floppy Fail the Apprentice Reader, How Biff, Kipper Abstract This article is the result of a re-examination of reading scheme books. Taking a literary perspective, the implied reader was investigated in the most popular scheme, The Oxford Reading nee, in order to ascertain how the reader is constructed by the text. It is argued that such texts covertly construct a passive, struggling reader. As such, this has important implications for the National Literacy Strategy, particularly in the selection of texts for Guided Reading. Summary Reading scheme books are designed to bridge the gap between the oral language of the child and the literary language of the book. What is considered important is a recognisable primary world. There is little dialogue yet the language is supposed to reflect that of the child. Short simple sentences devoid of cohesive devices are considered easier to read because the apprentice reader is deemed not to have stamina. Key words such as nouns and verbs are emphasised and little attention is paid to rhythm, hence few elisions and much repetition. As such the reading scheme does not reflect the language of the child for there is little colloquial expression and the lack of literary features actually makes the text very difficult to read. Implied is a reader who is going to find the whole process difficult and has little to bring to the text. On the other hand the children's literature analysed enjoys a variety of narratives and subject matter yet all support the apprentice reader. Such literary texts employ cohesive devices, the third person has a sense of telling with echoes of the oral tradition while those in first person offer a sense of a teller close to the reader. Direct speech is used, which acts as a bridge from the oral to the literary world. The reader is being guided and helped and not left to struggle. Ironically, it is the literary text that offers more support than the supposedly carefully constructed reading scheme. Furthermore, it can be seen that the reading scheme examined constructs a passive reader to whom things happen. The construction of childhood itself is without joy, excitement and wonder. There is a dullness in the text and a dullness in the characters and the plot that constructs a negative view of reading and a negative construction of the child. The model in Figure 1 summarises the difference between the two types of text: Clearly this has implications for texts selected for pupils to read in the National Literacy Strategy, particularly for Guided Reading. There is no shortage in the UK of appropriate, well-written and superbly illustrated children's books that challenge, support and create an interest in literature. It remains a mystery why the dull reading scheme still has such a strong place in the primary classroom. [source] Evaluation of poly(ethylene-co-vinyl acetate-co-carbon monoxide) and polydimethylsiloxane for equilibrium sampling of polar organic contaminants in waterENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2009Jörgen A Magnér Abstract Abstract-The aim of the present study was to develop a passive a bsorptive equilibrium sampler that would enable the determination of the concentrations of polar organic compound (POC) in water more efficiently than existing techniques. To this end, a novel plastic material, poly(ethylene-co-vinyl acetate-co-carbon monoxide) (PEVAC), was evaluated and the results were compared with an existing silicone-based passive absorptive equilibrium device. Seven compounds (imidacloprid, carbendazim, metoprolol, atrazin, carbamazepine, diazinon, and chlorpyrifos), a mixture of pharmaceuticals, and pesticides with a logarithmic octanol-water partition coefficient ranging from 0.2 to 4.77 were selected as model substances for the experiments. The results showed that six of the seven selected POCs reached distribution equilibrium within 4 d in the two materials tested. A linear relation with a regression coefficient of more than 0.8906 between the established logarithmic absorbent-water partition coefficient and the calculated logarithmic dissociation partition coefficient of the selected compounds in the two polymers was observed. The correlation between these two coefficients was within one order of magnitude for the compounds that reached equilibrium in the two polymers, which demonstrates that both materials are suitable for mimicking biological uptake of POCs. The PEVAC material showed an enhanced sorption for all selected compounds compared to the silicone material and up to five times higher enrichment for the most polar compound. Fluorescence analysis of the sampler cross-section, following the uptake of fluoranthene, and proof that the sorption was independent of surface area variations demonstrated that the PEVAC polymer possessed absorptive rather than adsorptive enrichment of organic compounds. [source] Communications skills in dental education: a systematic research reviewEUROPEAN JOURNAL OF DENTAL EDUCATION, Issue 2 2010J. A. Carey Abstract Communication is an essential element of the relationship between patient and dentist. Dental schools are required to ensure that undergraduates are adequately trained in communication skills yet little evidence exists to suggest what constitutes appropriate training and how competency can be assessed. This review aimed to explore the scope and quality of evidence relating to communication skills training for dental students. Eleven papers fitted the inclusion criteria. The review found extensive use amongst studies of didactic learning and clinical role-play using simulated patients. Reported assessment methods focus mainly on observer evaluation of student interactions at consultation. Patient involvement in training appears to be minimal. This review recommends that several areas of methodology be addressed in future studies, the scope of research extended to include intra-operative communication, and that the role of real patients in the development of communication skills be active rather than passive. [source] Neutralization of IL-17 by active vaccination inhibits IL-23-dependent autoimmune myocarditisEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 11 2006Ivo Sonderegger Abstract The most common reason for heart failure in young adults is dilated cardiomyopathy often resulting from myocarditis. Clinical studies and animal models provide evidence that an autoimmune response against heart myosin is the underlying reason for the disease. IL-12 has been suggested to play a key role in development of experimental autoimmune myocarditis (EAM), as IL-12p40 and IL-12R,1 knockouts are protected from disease. In this study, we have compared IL-12p40,/, mice, IL-12p35,/, mice and mice treated with a neutralizing IL-23 antibody in EAM and found that in fact IL-23, not IL-12, is responsible for inflammatory heart disease. However, these cytokines appear to have redundant activity for priming and expansion of autoreactive CD4 T cells, as specific T cell proliferation was only defective in the absence of both cytokines. IL-23 has been suggested to promote a pathogenic IL-17-producing T cell population. We targeted IL-17 by capitalizing on an active vaccination approach that effectively breaks B cell tolerance. Neutralization of IL-17 reduced myocarditis and heart autoantibody responses, suggesting that IL-17 is the critical effector cytokine responsible for EAM. Thus, targeting of IL-23 and IL-17 by passive and active vaccination strategies holds promise as a therapeutic approach to treat patients at risk for development of dilated cardiomyopathy. See accompanying commentary: http://dx.doi.org/10.1002/eji.200636760 [source] Structural and Theoretical Insights into Metal,Scorpionate Ligand ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 10 2007Matthias Schwalbe Abstract The syntheses of the complexes [M(TmMe)(CO)2(NO)] (M = Mo, W) by reaction of NOBF4 with [M(TmMe)(CO)3], are reported and their spectroscopic characterisation and crystal structures are described. The analogous Cr complex could not be prepared by this methodology. The complexes adopt the expected pseudo-octahedral geometry. Complexes [M(L)(CO)2(NO)] (M = Cr, Mo, W; L = Cp, Tp and TmMe) together with the hypothetical [Mo(CO)2(NO)]+ cation were subjected to DFT calculations. Geometry-optimised structures closely parallel the crystallographic determinations and indicate that the complex [Cr(TmMe)(CO)2(NO)] is not inherently unstable. The DFT calculations allow the assignment of the C,O and N,O stretches in the IR spectrum and give insight into both the M,NO bonding and the metal to tripodal ligand bonding. The electron-donor strengths are confirmed to lie in the order TmMe > Tp > Cp. A side reaction of the B,H moiety of the TmMe anion with NO+ results in the isolation of the dimethylformamide adduct of (trismethimazolyl)borane, providing further evidence that the reaction pathways of the TmR ligands are more varied and less passive than in the chemistry of the nitrogen-based scorpionates.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Facilitation of corticospinal excitability in the tibialis anterior muscle during robot-assisted passive stepping in humansEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2009Kiyotaka Kamibayashi Abstract Although phasic modulation of the corticospinal tract excitability to the lower limb muscles has been observed during normal walking, it is unclear to what extent afferent information induced by walking is related to the modulation. The purpose of this study was to test the corticospinal excitability to the lower limb muscles by using transcranial magnetic stimulation (TMS) and transcranial electrical stimulation of the motor cortex while 13 healthy subjects passively stepped in a robotic driven-gait orthosis. Specifically, to investigate the effect of load-related afferent inputs on the corticospinal excitability during passive stepping, motor evoked potentials (MEPs) in response to the stimulation were compared between two passive stepping conditions: 40% body weight unloading on a treadmill (ground stepping) and 100% body weight unloading in the air (air stepping). In the rectus femoris, biceps femoris and tibialis anterior (TA) muscles, electromyographic activity was not observed throughout the step cycle in either stepping condition. However, the TMS-evoked MEPs of the TA muscle at the early- and late-swing phases as well as at the early-stance phase during ground stepping were significantly larger than those observed during air stepping. The modulation pattern of the transcranial electrical stimulation-evoked MEPs was similar to that of the TMS-evoked MEPs. These results suggest that corticospinal excitability to the TA is facilitated by load-related afferent inputs. Thus, these results might be consistent with the notion that load-related afferent inputs play a significant role during locomotor training for gait disorders. [source] Effects of attention and arousal on early responses in striate cortexEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2005Vahe Poghosyan Abstract Humans employ attention to facilitate perception of relevant stimuli. Visual attention can bias the selection of a location in the visual field, a whole visual object or any visual feature of an object. Attention draws on both current behavioral goals and/or the saliency of physical attributes of a stimulus, and it influences activity of different brain regions at different latencies. Attentional effect in the striate and extrastriate cortices has been the subject of intense research interest in many recent studies. The consensus emerging from them places the first attentional effects in extrastriate areas, which in turn modulate activity of V1 at later latencies. In this view attention influences activity in striate cortex some 150 ms after stimulus onset. Here we use magnetoencephalography to compare brain responses to foveally presented identical stimuli under the conditions of passive viewing, when the stimuli are irrelevant to the subject and under an active GO/NOGO task, when the stimuli are cues instructing the subject to make or inhibit movement of his/her left or right index finger. The earliest striate activity was identified 40,45 ms after stimulus onset, and it was identical in passive and active conditions. Later striate response starting at about 70 ms and reaching a peak at about 100 ms showed a strong attentional modulation. Even before the striate cortex, activity of the right inferior parietal lobule was modulated by attention, suggesting this region as a candidate for mediating attentional signals to the striate cortex. [source] Enhancement of learning behaviour by a potent nitric oxide-guanylate cyclase activator YC-1EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2005Wei-Lin Chien Abstract Memory is one of the most fundamental mental processes, and various approaches have been used to understand the mechanisms underlying this process. Nitric oxide (NO), cGMP and protein kinase G (PKG) are involved in the modulation of synaptic plasticity in various brain regions. YC-1, which is a benzylindazole derivative, greatly potentiated the response of soluble guanylate cyclase to NO (up to several hundreds fold). We have previously shown that YC-1 markedly enhances long-term potentiation in hippocampal and amygdala slices via NO-cGMP-PKG-dependent pathway. We here further investigated whether YC-1 promotes learning behaviour in Morris water maze and avoidance tests. It was found that YC-1 shortened the escape latency in the task of water maze, increased and decreased the retention scores in passive and active avoidance task, respectively. Administration of YC-1 30 min after foot-shock stimulation did not significantly affect retention scores in response to passive avoidance test. Administration of scopolamine, a muscarinic antagonist, markedly impaired the memory acquisition. Pretreatment of YC-1 inhibited the scopolamine-induced learning deficit. The enhancement of learning behaviour by YC-1 was antagonized by intracerebroventricular injection of NOS inhibitor L-NAME and PKG inhibitors of KT5823 and Rp-8-Br-PET-cGMPS, indicating that NO-cGMP-PKG pathway is also involved in the learning enhancement action of YC-1. YC-1 is thus a good drug candidate for the improvement of learning and memory. [source] Design and comparison of different flux-switch synchronous machines for an aircraft oil breather applicationEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 6 2005Yacine Amara This paper presents a design procedure of a flux,switch synchronous machine for an aircraft oil breather application. This work is part of a European project called ,Power Optimised Aircraft'. The aim of this project is to replace some mechanical equipment by electromechanical devices to improve performance and reduce power consumption. The structure under study was developed at SATIE laboratory and it is based on the flux-switch principle. The permanent magnets are located in the stator, and the rotor is entirely passive. The study described in this paper is limited to the electromagnetic design. Copyright © 2005 John Wiley & Sons, Ltd. [source] The action of high K+ and aglycaemia on the electrical properties and synaptic transmission in rat intracardiac ganglion neurones in vitroEXPERIMENTAL PHYSIOLOGY, Issue 2 2009Jhansi Dyavanapalli We have investigated the action of two elements of acute ischaemia, high potassium and aglycaemia, on the electrophysiological properties and ganglionic transmission of adult rat intracardiac ganglion (ICG) neurones. We used a whole-mount ganglion preparation of the right atrial ganglion plexus and sharp microelectrode recording techniques. Increasing extracellular K+ from its normal value of 4.7 mm to 10 mm decreased membrane potential and action potential after-hyperpolarization amplitude but otherwise had no effect on postganglionic membrane properties. It did, however, reduce the ability of synaptically evoked action potentials to follow high-frequency (100 Hz) repetitive stimulation. A further increase in K+ changed both the passive and the active membrane properties of the postganglionic neurone: time constant, membrane resistance and action potential overshoot were all decreased in high K+ (20 mm). The ICG neurones display a predominantly phasic discharge in response to prolonged depolarizing current pulses. High K+ had no impact on this behaviour but reduced the time-dependent rectification response to hyperpolarizing currents. At 20 mm, K+ practically blocked ganglionic transmission in most neurones at all frequencies tested. Aglycaemia, nominally glucose-free physiological saline solution (PSS), increased the time constant and membrane resistance of ICG neurones but otherwise had no action on their passive or active properties or ganglionic transmission. However, the combination of aglycaemia and 20 mm K+ displayed an improvement in passive properties and ganglionic transmission when compared with 20 mm K+ PSS. These data indicate that the presynaptic terminal is the primary target of high extracellular potassium and that aglycaemia may have protective actions against this challenge. [source] | ||||||||||||||||||||||||||||||||||||||||||||||||||||