scholarly journals The Hybrid Drive: a chronic implant device combining tetrode arrays with silicon probes for layer-resolved ensemble electrophysiology in freely moving mice

2021 ◽  
Author(s):  
Matteo Guardamagna ◽  
Ronny Eichler ◽  
Rafael Pedrosa ◽  
Arno Aarts ◽  
Arne F Meyer ◽  
...  
Keyword(s):  
Oscillatory Activity ◽  
Hybrid Drive ◽  
Spatial And Temporal Scales ◽  
Large Numbers ◽  
Pyramidal Layer ◽  
Major Species ◽  
Weight Structure ◽  
Series Of Experiments ◽  
Electrophysiological Signal ◽  
Silicon Probes

Understanding the function of brain cortices requires simultaneous investigation at multiple spatial and temporal scales and to link neural activity to an animal's behavior. A major challenge is to measure within- and across-layer information in actively behaving animals, in particular in mice that have become a major species in neuroscience due to an extensive genetic toolkit. Here we describe the Hybrid Drive, a new chronic implant for mice that combines tetrode arrays to record within-layer information with silicon probes to simultaneously measure across-layer information. The flexible, open-source design allows custom spatial arrangements of tetrode arrays and silicon probes to generate areas-specific layouts. We show that large numbers of neurons and layer-resolved local field potentials can be recorded from the same brain region across weeks without loss in electrophysiological signal quality. The drive's light-weight structure (3.5 g) leaves animal behavior largely unchanged during a variety of experimental paradigms, enabling the study of rich, naturalistic behaviors. We demonstrate the power of the Hybrid Drive in a series of experiments linking the spiking activity of CA1 pyramidal layer neurons to the oscillatory activity across hippocampal layers.

Stimulated Glanzmann’s Thrombasthenia Platelets Produce Microvesicles

1995 ◽  
Vol 74 (06) ◽  
pp. 1533-1540 ◽  
Author(s):  
Pål André Holme ◽  
Nils Olav Solum ◽  
Frank Brosstad ◽  
Nils Egberg ◽  
Tomas L Lindahl
Keyword(s):  
Complement System ◽  
Shape Change ◽  
Annexin V ◽  
Platelet Surface ◽  
Glanzmann’S Thrombasthenia ◽  
Large Numbers ◽  
Glanzmann's Thrombasthenia ◽  
Series Of Experiments ◽  
The Complement System ◽  
Number Of Particles

SummaryThe mechanism of formation of platelet-derived microvesicles remains controversial.The aim of the present work was to study the formation of microvesicles in view of a possible involvement of the GPIIb-IIIa complex, and of exposure of negatively charged phospholipids as procoagulant material on the platelet surface. This was studied in blood from three Glanzmann’s thrombasthenia patients lacking GPIIb-IIIa and healthy blood donors. MAb FN52 against CD9 which activates the complement system and produces microvesicles due to a membrane permeabilization, ADP (9.37 μM), and the thrombin receptor agonist peptide SFLLRN (100 μM) that activates platelets via G-proteins were used as inducers. In a series of experiments platelets were also preincubated with PGE1 (20 μM). The number of liberated microvesicles, as per cent of the total number of particles (including platelets), was measured using flow cytometry with FITC conjugated antibodies against GPIIIa or GPIb. Activation of GPIIb-IIIa was detected as binding of PAC-1, and exposure of aminophospholipids as binding of annexin V. With normal donors, activation of the complement system induced a reversible PAC-1 binding during shape change. A massive binding of annexin V was seen during shape change as an irreversible process, as well as formation of large numbers of microvesicles (60.6 ±2.7%) which continued after reversal of the PAC-1 binding. Preincubation with PGE1 did not prevent binding of annexin V, nor formation of microvesicles (49.5 ± 2.7%), but abolished shape change and PAC-1 binding after complement activation. Thrombasthenic platelets behaved like normal platelets after activation of complement except for lack of PAC-1 binding (also with regard to the effect of PGE1 and microvesicle formation). Stimulation of normal platelets with 100 μM SFLLRN gave 16.3 ± 1.2% microvesicles, and strong PAC-1 and annexin V binding. After preincubation with PGE1 neither PAC-1 nor annexin V binding, nor any significant amount of microvesicles could be detected. SFLLRN activation of the thrombasthenic platelets produced a small but significant number of microvesicles (6.4 ± 0.8%). Incubation of thrombasthenic platelets with SFLLRN after preincubation with PGE1, gave results identical to those of normal platelets. ADP activation of normal platelets gave PAC-1 binding, but no significant annexin V labelling, nor production of microvesicles. Thus, different inducers of the shedding of microvesicles seem to act by different mechanisms. For all inducers there was a strong correlation between the exposure of procoagulant surface and formation of microvesicles, suggesting that the mechanism of microvesicle formation is linked to the exposure of aminophospholipids. The results also show that the GPIIb-IIIa complex is not required for formation of microvesicles after activation of the complement system, but seems to be of importance, but not absolutely required, after stimulation with SFLLRN.

scholarly journals Effect of culture medium light and air circulation on sporulation of Neonectria ditissima

2014 ◽  
Vol 67 ◽  
pp. 123-132 ◽  
Author(s):  
R.W.A. Scheper ◽  
B.M. Fisher ◽  
N.T. Amponsah ◽  
M. Walter
Keyword(s):  
Culture Media ◽  
Ultra Violet ◽  
Fluorescent Light ◽  
Malt Extract ◽  
Causal Organism ◽  
Light Regimes ◽  
Large Numbers ◽  
Light Darkness ◽  
Series Of Experiments ◽  
Air Circulation

In culture most isolates of Neonectria ditissima the causal organism of European canker do not produce conidia Those that do often produce singlecelled conidia rather than the typical multicelled conidia that are found in nature A series of experiments was conducted to determine the conditions needed for conidium production Four culture media (malt extract agar modified Matsushimas medium (MM) apple sap amended water agar (ASAWA) and water agar) five light regimes including darkness near ultra violet (NUV) light and white fluorescent light and three plate sealing patterns were tested Subculturing isolates producing large numbers of viable conidia of which 71 produced multicelled conidia Similarly under a white fluorescent light/darkness regime all isolates produced viable conidia on MM and ASAWA and 100 and 97 of the isolates produced multicelled conidia respectively

scholarly journals Platelet Alterations Caused by Antiplatelet Antibodies in the Circulation

1977 ◽  
Author(s):  
T. Nagasawa ◽  
B.K. Kim ◽  
M.G. Baldini
Keyword(s):  
Platelet Count ◽  
Specific Activity ◽  
Rabbit Model ◽  
Antiplatelet Antibodies ◽  
Large Numbers ◽  
Severe Reduction ◽  
Series Of Experiments ◽  
Specific Activities

It is known that antiplatelet antibodies cause loss of platelet cytoplasmic and granular contents in vitro. It is, however, unknown whether similar platelet changes occur in vivo, in the circulation, leading to destruction and phagocytosis of platelets in the R.E. system. To study this possibility a rabbit model was devised. Severe and stable thrombocytopenia was first produced in rabbits by one intravenous injection of Adriamycin. Large numbers of allogenic platelets labeled in vitro with 51Cr and 14C-serotonin were then infused to raise the circulating platelet count to 180-250 × 103/mm3. A dilute heteroimmune antiplatelet serum prepared in the guinea pig was infused intravenously and platelet samples were collected four times during the subsequent 30 minutes to 24 hours. Platelet hexokinase and β-glucuronidase, 14C-serotonin and 51Cr were measured. Within the first 60 min the specific activity of 51Cr in platelets decreased by 21%, 14C-serotonin declined by 30%, hexokinase by 5% and β-glucuronidase by 29%. During the subsequent 24 hours only 51Cr and hexokinase registered a mild decrease but 51C-serotonin and β-glucuronidase remained essentially unchanged. In a second series of experiments the effect of platelet alloantibodies was studied in rabbits previously immunized with allogenic platelets. The decline in the specific activities of the enzymes and 14C-serotonin was similar to that observed in animals treated with heteroimmune sera but loss of 51Cr was more severe. These results demonstrate that the platelets remaining in the circulation after the disappearance of the immediate effect of hetero- or alloantibodies were qualitatively altered with a severe reduction of their granular and cytoplasmic contents.

A Device for the rapid Counting of large Numbers of small Insects

1936 ◽  
Vol 27 (2) ◽  
pp. 269-271
Author(s):  
P. S. Milne
Keyword(s):  
Insect Trap ◽  
Large Numbers ◽  
Series Of Experiments ◽  
Speed And Accuracy

During a series of experiments at Rothamsted with the mechanical insect trap described by Williams & Milne (Bull. Ent. Res. 1935, 26, p. 543) it became necessary to make counts of large numbers of insects three or four times a day over periods of several weeks. The following is a description of a device which was designed to facilitate the handling of the insects and to increase the speed and accuracy of the counting.

Accuracies associated with the automated electron probe analysis of particulate populations

1992 ◽  
Vol 50 (2) ◽  
pp. 1494-1495
Author(s):  
John A. Small ◽  
Matthew A. Calderone
Keyword(s):  
Electron Probe ◽  
Compositional Analysis ◽  
Beam Current ◽  
Electron Probe Analysis ◽  
Electron Dose ◽  
Large Numbers ◽  
Series Of Experiments ◽  
The Individual ◽  
Automated Scanning ◽  
Individual Particles

The analysis of large numbers of particles by automated scanning electron microscopy/ electron probe (ASEM) has been used in conjunction with multivariate analysis algorithms to classify atmospheric particles into different groups based on size, shape, and elemental composition. These groups or clusters and the number of particles belonging to each are often used to develop source apportionment for the sampled aerosol.There are several limitations particularly with the compositional analysis aspects of the automated routines that may limit the information that can be obtained from the sample. One of the major limitations of ASEM analyses is associated with the relatively short counting times, typically between 10-30 s, used for the accumulation of x-ray spectra from the individual particles. In contrast, the counting times used for conventional electron probe analyses are on the order of 5 minutes.We are conducting a series of experiments to study the effects of accelerating voltage, and electron dose (beam current, and counting time) on the accuracy, precision, and detection limits of ASEM analyses. The degradation of accuracy, precision and detection will have a pronounced effect on the separation of particles with similar but different elemental compositions into groups.

Spatial-temporal patterns of self-organization: A dynamic 4D model for redeveloping the post-zoning city

2021 ◽  
pp. 239980832110413
Author(s):  
Daphna Levine ◽  
Shai Sussman ◽  
Meirav Aharon-Gutman
Keyword(s):  
Urban Planning ◽  
Planning System ◽  
Self Organization ◽  
Planning Support Systems ◽  
Web Based ◽  
Spatial And Temporal Scales ◽  
Urban Dynamics ◽  
Self Organized ◽  
Large Numbers ◽  
Flexible Planning

Time is the main axis for understanding the functional, economic, and social aspects of self-organized redevelopment. When such processes are intensive and are conducted contemporaneously by large numbers of urban agents on different spatial and temporal scales and as a result of different motivations, urban planning is fragmented into multiple simultaneous and unexpected projects. The post-zoning era in urban planning stemmed from a recognition of this kind of complexity of urban dynamics and the need for a flexible planning system. Web-based geographic information systems (GIS) and planning support systems (PSS) are employed widely as digital tools to support planning practices. Still, the solutions tend to be isolated implementations that do not achieve sophisticated management of the complex temporal-spatial urban dynamics of self-organization. To this end, the article presents a useful set of multidimensional (2D, 3D, and 4D) planning tools that can be implemented by municipal planning departments to improve planning practices with relative ease. This toolbox facilitates the real-time updating of changes to individual buildings and allows all parties to see where delays are occurring, where they are impacting one another, and where environments of accelerated development are evolving in nearby urban plots. Identifying redevelopment clusters enables the formulation of an urban time-based planning policy. Using a spatial-temporal toolbox for planning, we argue, can facilitate recognition of the potential of self-organization as the leading form of contemporary urban planning.

Early Paleoindian Women, Children, Mobility, and Fertility

2000 ◽  
Vol 65 (3) ◽  
pp. 493-508 ◽  
Author(s):  
Todd A. Surovell
Keyword(s):  
High Mobility ◽  
Archaeological Sites ◽  
High Fertility ◽  
Archaeological Record ◽  
Hunter Gatherers ◽  
Spatial And Temporal Scales ◽  
Raising Children ◽  
Large Numbers ◽  
Colonization Process ◽  
Reproductive Rates

If we take the archaeological record at face value, the colonization of unglaciated North America appears to have been very rapid. The highly consistent dating of Clovis archaeological sites (11,500-10,800 B.P.) suggests that this continent was populated within a matter of centuries. To explain the spatial and temporal scales of this phenomenon, it is necessary to invoke both high mobility and high fertility rates during the initial colonization process. However, it is widely believed that it is maladaptive for mobile foragers to have large numbers of offspring due to the costs of transporting those children. Thus, the archaeological record presents us with a paradox. Using a mathematical model that estimates the costs of raising children for mobile hunter-gatherers, this paper asks the question-is high mobility compatible with high fertility? It is concluded that high mobility, if defined as the frequent movement of residential base camps, is quite compatible with high fertility, and that early Paleoindians could indeed have been characterized by high reproductive rates. Therefore, it is quite possible that the Americas were populated very rapidly by highly mobile hunter-gatherers.

Role of the dog, fox, cat and human as carnivore vectors in the transmission of the Sarcosporidia that affect sheep meat production

1986 ◽  
Vol 37 (1) ◽  
pp. 79 ◽  
Author(s):  
GE Ford
Keyword(s):  
Meat Production ◽  
Predator Prey ◽  
Source Of Infection ◽  
Sheep Meat ◽  
Large Numbers ◽  
Faecal Samples ◽  
Pasture Contamination ◽  
Series Of Experiments ◽  
Sheep Production ◽  
Meat Animal

The roles of six carnivores as potential sources to sheep of the sarcosporidial parasites causing cysts in meat were compared in a series of experiments carried out between 1973 and 1980. The research was concomitant with other studies that confirmed the prey-predator-prey-predator cycle of transmission. Infected carnivores act as vectors, excreting in their faeces coccidial sporocysts infective to the meat animal. For 60 experimental infections, sheep meat containing sarcocysts or sarcocysts removed from sheep meat were fed to experimental carnivores. Faecal samples were examined for sporocysts over 60 days post infection. Neither macroscopic (visible) sarcocysts nor microscopic sarcocysts from sheep carcasses were transmissible by humans or by ferrets (domestic polecats). Microscopic sarcocysts were readily infective to dogs, both domestic and dingo, as well as to foxes, but not to cats. Large numbers of sporocysts that could contaminate the environment were excreted. Both fat and thin visible sarcocysts were transmitted exclusively to cats. Although cats responded with relatively low levels of sporocysts, these were considered adequate to provide sufficient pasture contamination for the life cycle to be perpetuated. It is concluded that, while domestic dogs may be the greatest source of infection for sheep with microscopic sarcocysts, foxes as vectors also pose a threat to sheep production. Similarly, due to their widespread presence, feral cats play a role as well as domestic or semi-domestic cats in the spread of sarcocysts causing visible carcass lesions.

scholarly journals Use of otolith quality flags to assess distributional dynamics in Baltic cod stocks

2016 ◽  
Vol 67 (7) ◽  
pp. 980 ◽  
Author(s):  
Sven Stötera ◽  
Uwe Krumme
Keyword(s):  
Close Association ◽  
Western Basin ◽  
Spatial And Temporal Scales ◽  
Large Numbers ◽  
Western Area ◽  
Mixing Dynamics ◽  
Basin Topography ◽  
Distributional Dynamics ◽  
The Baltic ◽  
Baltic Cod

In the Baltic Sea, cod spawn in several basins separated by shallower sills. The mixing dynamics between two cod stocks and their components remain largely unclear, yet such mixing has gained attention in recent years because signs of recovery in the eastern Baltic cod population suggested spillover into the western basin. In the present study, we assessed whether quality flags (QF) of cod otoliths (QF categories: readable, uncertain or unreadable) can be used to evaluate spillover. Analysis of ~80000 otoliths taken between 2007 and 2013 showed that the Darß and Drogden sills consistently separated large numbers of readable otoliths in the shallower western area (subdivision (SD) 21–SD23) from large proportions of uncertain and unreadable otoliths in the deeper eastern basins (SD25–SD29). SD24 was a mixing area: the western statistical rectangles resembled SD22 and SD23, whereas the eastern rectangles resembled SD25, in close association with basin topography. QF proportions did not differ on the various spatial and temporal scales examined, regardless of grouping by sex or length class. This suggests that increased spillover from the east has not occurred since 2007. However, the large proportion of uncertain otoliths in SD24 and inconsistencies in QF determination may mask the detection of trends in mixing.

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