Thy-1 is a component common to multiple populations of synaptic vesicles

To understand the influence of the ascending path linking area 17 to area 18 of visual cortices, experiments were carried out in which a small neuronal population of area 17 was inactivated with GABA, while unitary responses were recorded in area 18. In the latter, cells are identified as belonging to the simple or complex family according to their firing pattern evoked in response to sine-wave gratings scrolling through the receptive fields. Anesthetized cats were prepared for single-cell recordings. In area 17, a GABA-containing pipette was placed in superficial layers in order to inactivate reversibly a small neuronal population. Prior to blockade, the orientation tuning curves were obtained in both areas and the difference in optimal orientation between areas 17 and 18 was recorded. In area 18, cells were classified as simple or complex. The strategy was to study the reaction of neurons in area 18 prior to, during and after area 17 depression. In most simple cells, whenever the difference in orientation was in the iso-range, that is when the difference in optimal orientations of the injected site (in area 17) and of the neuron in area 18 was less than 30 degrees, the GABA application produced a decline of the evoked discharges, whereas GABA injection augmented the evoked firing rate when the difference was in the cross-range (>60 degrees). In contrast to simple cells, GABA depression enhanced the responses in the majority of complex cells with like orientations in both areas. When the difference between recording sites was in the cross-range, then area 17 depression produced weaker evoked firing. A tangential penetration of the injecting pipette, allowing injection of different orientation sites while testing the same unit in area 18, revealed that the latter could react with an enhancement or a decline of the responses as the injecting pipette shifted from iso (or cross) to cross (or iso) disparity in optimal orientations between areas 17 and 18. These results suggest that the path connecting area 17 to area 18 may be functionally discriminated on the basis of the orientation domain and cell types. In addition, our data suggest that the ascending visual streams are required to generate orientation specificity in area 18.     

Patterns of GFAP-immunoreactivity parallel the tonotopic axis in the developing dorsal cochlear nucleus

The gain of the H reflex attenuates during passive stepping and pedalling movements of the leg. We hypothesized that the kinematics of the movement indirectly reflect the receptor origin of this attenuation. In the first experiment, H reflexes were evoked in soleus at 26 points in the cycle of slow, passive pedalling movement of the leg and at 13 points with the leg static (the ankle was always immobilized). Maximum inhibition occurred as the leg moved through its most flexed position (P < 0.05). Inhibition observed in the static leg was also strongest at this position (P < 0.05). The increase in inhibition was gradual during flexion movement, with rapid reversal of this increase during extension. In the second experiment, the length of stretch of the vasti muscles was modelled. Variable pedal crank lengths and revolutions per minute (rpm) altered leg joint displacements and angular velocities. Equivalent rates of stretch of the vasti, achieved through different combinations of joint displacements and velocities, elicited equivalent attenuations of mean reflex magnitudes in the flexed leg. Reflex gain exponentially related to rate of stretch (R2 = 0.98 P < 0.01). The results imply that gain attenuation of this spinal sensorimotor path arises from spindle discharge in heteronymous extensor muscles of knee and/or hip, concomitant with movement.     

The use of cluster analysis for cell typing

BACKGROUND: Experiments were designed to evaluate the effect of warm blood cardioplegia on endothelium-dependent contraction of the coronary endothelium after cardiac global ischemia and reperfusion. METHOD: Dogs (n = 12 in each group) were exposed to extracorporeal circulation with the body temperature at 37 degrees C (group 1) or 28 degrees C (groups 2 and 3). The ascending aorta was crossclamped for 120 minutes while continuous infusion of warm blood cardioplegec solution (group 1) or intermittent infusion of cold (4 degrees C) crystalloid cardioplegic solution (group 2) was performed via the coronary arteries through the aortic root. Cardioplegic solution was not used in group 3 animals. The heart was then allowed to function for 60 minutes of reperfusion. Reperfused (groups 1, 2, and 3) and control (group 4) coronary arteries were then harvested for study. RESULTS: Perfusate hypoxia caused endothelium-dependent contraction in the arteries of all four groups that could be attenuated by NG-monomethyl-L-arginine (L-NMMA) or L-NMMA plus D-arginine, but not by L-NMMA plus L-arginine or endothelin receptor A and B antagonist PD 145065. The endothelium-dependent contraction results in groups 2 and 3 (75% +/- 4% and 80% +/- 5%, respectively) were significantly greater than those in groups 1 and 4 (15% +/- 3% and 18% +/- 5%, respectively). Scanning electron microscope studies showed that platelet adhesion and aggregation, areas of microthrombi, disruption of endothelial cells, and separation of the intercellular junction could be found in coronary segments from groups 2 and 3, but not in vessels from groups 1 and 4. CONCLUSION: These experiments suggest that global ischemia and reperfusion enhances hypoxia-mediated endothelium-dependent contraction of the coronary endothelium and damages the ultrastructure. These kinds of changes can be prevented by continuous antegrade infusion of warm blood cardioplegic solution during global ischemia.     

Posttransplantation lymphoproliferative disorder associated with OKT3 and decreased antiviral prophylaxis in pancreas transplant recipients

Between September 1994 and October 1995, we diagnosed and treated four cases of early onset posttransplantation lymphoproliferative disorder (PTLD) occurring within 62 days of pancreas transplantation. The development of PTLD was associated with both a significantly higher total muromonab-CD3 (OKT3) dose and a lack of ganciclovir/acyclovir prophylaxis, but it was not associated with the total dose of antithymocyte globulin or cytomegalovirus serostatus. All four patients were treated aggressively and survived without evidence of recurrent PTLD more than 1.5 years later. We conclude that the use of a high total dose of OKT3 puts pancreas transplant recipients at increased risk for early onset PTLD, while ganciclovir/acyclovir prophylaxis may help to prevent this disorder; however, if early onset PTLD does occur in these patients, aggressive therapy can lead to a favorable outcome.     

Analysis of flexible manufacturing systems with distinct repeated visits: DrQ

This article examines the performance effects caused by repeated part visits at the workstations of a flexible manufacturing system (FMS). Such repeated part visits to the same workstations are commonly associated with fixture changes for machining complex parts, reclamping, and remounting or reorienting them. Since each of the repeated visits to a workstation may require different processing requirements, the resulting queueing network does not have a product form solution. We therefore develop an approximate mean value analysis model for performance evaluation of an FMS that may produce multiple part types with distinct repeated visits.We provide numerical examples and validate the accuracy of our solution algorithm against simulation. These examples show that the proposed model produces accurate throughput and utilization predictions with minimal computational efforts. These examples reveal that increasing the total pallet population may result in a reduction of the aggregate throughput, and that the FMS's performance could be more sensitive to the mix of pallets and part routes than to the total number of pallets. Our model will be of use, in particular, when managers wish to control individual operations (e.g., to adjust individual operation times to achieve economic savings in tool wear and breakage costs) or to investigate the performance implications of route changes due to alternate assignments of particular manufacturing tasks to certain workstations.     

Of Embodied Action and Sensors: Knowledge and Expertise Sharing in Industrial Set-Up

Knowledge and expertise sharing has long been an important theme in CSCW and, importantly, one that has frequently challenged a prevailing view concerning knowledge management. This critique focused, initially, on the practical problems associated with issues of Organisational Memory (OM), and in particular the difficulties inherent in an oversimplified ‘repository’ model. Attention then turned to issues of contextuality and communication for expertise sharing, drawing on concepts such as communities of practice and social capital to understand, again, the sharing of knowledge and expertise in practice. Here, we report on how particular kinds of ‘embodied action’ can be identified in relation to the potential of cyber-physical infrastructures for knowledge sharing in an industrial context. We argue that, in a complex industrial domain, both the recording of physical movement – ‘showing’ – and the representation of local knowledge – ‘telling’ – are potentially relevant. Our proposal is that the evolution of cyber-physical infrastructures now offers a way of changing some early assumptions about how knowledge might be captured and displayed. We argue that we are entering a third generation of knowledge and expertise sharing research, where the use of augmented reality (AR) and sensor technology will result in significant new methodological innovations, including the capture and sharing of knowledge, embedded in embodied action.     

Effect of neutron irradiations on superconducting properties of A-15 compounds undoped and doped with 10B and 235U

The effect of lattice damage caused by room temperature irradiations with products of ¹⁰B(n, )⁷ Li reactions and ²³⁵U fissions and with fast neutrons on transition curves, quenching curves, and lattice constants of Nb₃Sn, Nb₃Al, Nb₃(Al, Ge), and V₃Si have been investigated. The critical currents in transverse magnetic fields could be increased up to more than one order of magnitude. For heavily irradiated samples drastically reduced values for the critical currents, the upper critical fields, and the transition temperatures were observed. The lattice constants were increased up to 0.5%; by irradiation.Some of the results in this paper were presented at the International Discussion Meeting on Flux Pinning in Superconductors, St. Andreasberg, West Germany, September 23–27, 1974.Part of this work was performed while the author was a Guest Scientist at the Brookhaven National Laboratory, Upton, New York, and at the Francis Bitter National Magnet Laboratory, which is supported at M.I.T. by the National Science Foundation.Work supported by the Deutsche Forschungsgemeinschaft.Work supported by the U. S. Atomic Energy Commission.     

The Mediatization of E‐Campaigning: Evidence From German Party Websites in State,National, and European Parliamentary Elections 2002–2009

The rise of e‐campaigning is often associated with its ability to circumvent journalistic principles of news selection and presentation. By this, parties and candidates are said to free themselves from the discretionary power of the mass media and to reach voters in an unfiltered way. This conventional wisdom is tested through a comparative content analysis of German party websites in state, national, and European parliamentary elections between 2002 and 2009. The results show that e‐campaigns in all elections adhere in their messages to the media logic. Specifically, they replicate those patterns of offline coverage that have been held accountable for rising political alienation and civic apathy. Moreover, the mediatization of German e‐campaigning grows over time.