15 research outputs found
A Neural Correlate of Predicted and Actual Reward-Value Information in Monkey Pedunculopontine Tegmental and Dorsal Raphe Nucleus during Saccade Tasks
Dopamine, acetylcholine, and serotonin, the main modulators of the central nervous system, have been proposed to play important roles in the execution of movement, control of several forms of attentional behavior, and reinforcement learning. While the response pattern of midbrain dopaminergic neurons and its specific role in reinforcement learning have been revealed, the role of the other neuromodulators remains rather elusive. Here, we review our recent studies using extracellular recording from neurons in the pedunculopontine tegmental nucleus, where many cholinergic neurons exist, and the dorsal raphe nucleus, where many serotonergic neurons exist, while monkeys performed eye movement tasks to obtain different reward values. The firing patterns of these neurons are often tonic throughout the task period, while dopaminergic neurons exhibited a phasic activity pattern to the task event. The different modulation patterns, together with the activity of dopaminergic neurons, reveal dynamic information processing between these different neuromodulator systems
Inhibition of Ras activity coordinates cell fusion with cell-cell contact during yeast mating.
In the fission yeast Schizosaccharomyces pombe, pheromone signaling engages a signaling pathway composed of a G protein-coupled receptor, Ras, and a mitogen-activated protein kinase (MAPK) cascade that triggers sexual differentiation and gamete fusion. Cell-cell fusion requires local cell wall digestion, which relies on an initially dynamic actin fusion focus that becomes stabilized upon local enrichment of the signaling cascade on the structure. We constructed a live-reporter of active Ras1 (Ras1-guanosine triphosphate [GTP]) that shows Ras activity at polarity sites peaking on the fusion structure before fusion. Remarkably, constitutive Ras1 activation promoted fusion focus stabilization and fusion attempts irrespective of cell pairing, leading to cell lysis. Ras1 activity was restricted by the guanosine triphosphatase-activating protein Gap1, which was itself recruited to sites of Ras1-GTP and was essential to block untimely fusion attempts. We propose that negative feedback control of Ras activity restrains the MAPK signal and couples fusion with cell-cell engagement
Design and characterization of a linear quadrupole ion trap for high-resolution Coulomb-crystal time-of-flight mass spectrometry
The venodilation effects of tapping versus massaging for venipuncture
Aim To compare the effectiveness of tapping and massaging venodilation techniques by evaluating venous cross-sectional area, venous depth, venous palpation score, and questionnaire responses of study participants. Methods This study had a quasi-experimental design. Between August 2016 and October 2016, healthy adult volunteers (n = 30, mean +/- standard deviation of age: 22.3 +/- 2.2 years) were enrolled in this study. Three venodilation techniques were evaluated: the application of a tourniquet (Control Group), the application of a tourniquet and tapping of the participant's forearm (Tapping Group), and the application of a tourniquet and massaging of the participant's forearm (Massage Group). Results In all three groups, venous cross-sectional areas increased significantly after the application of the venodilation technique. The change ratio of venous cross-sectional area was significantly larger in the Massage Group than in the Control Group. Additionally, 83.3% of the participants selected massaging as their preferred venodilation technique, stating the technique was comfortable and provided a feeling of relief. Conclusions No significant differences were observed between the degrees of venodilation that were achieved using the three investigated venodilation techniques. Nonetheless, massaging was deemed the most effective technique after considering the participants' subjective comments
Do Tapping and Massaging during Tourniquet Application Promote Dilation of Forearm Cutaneous Veins? A Pilot Quasi-Experimental Study
Successful insertion of a peripheral intravenous catheterization requires that veins be sufficiently dilated. This study aimed to clarify the venous dilation effect of including tapping or massaging to the application of a tourniquet at the cutaneous veins of healthy adults’ forearms. This was a quasi-experimental study of 30 healthy adult volunteers. Each participant underwent all three venous dilation procedures, which included the tourniquet application (Control condition), the tourniquet application and tapping the participant’s forearm (Tapping condition), as well as the tourniquet application combined with massaging the participant’s forearm (Massage condition). To clarify the venous dilation effects, venous indices were measured, namely the venous diameter (mm), depth (mm), and palpation score. After applying all venous dilation procedures, the venous diameter and palpation score significantly increased. However, no significant difference was observed between the control condition and each intervention condition. The depth in the control and tapping conditions decreased significantly in contrast to the Massage condition. Moreover, a subgroup (nine participants with a venous diameter less than 3 mm after the control condition) had similar results. This study found that additional tapping or massaging after tourniquet application could be less effective in promoting dilation in the forearm veins of healthy adults. Future studies should examine the efficacy and effectiveness of venous dilation in a wide target population while considering intervention methods
Do Tapping and Massaging during Tourniquet Application Promote Dilation of Forearm Cutaneous Veins? A Pilot Quasi-Experimental Study
Paleomagnetism and paleomagnetic dating to large volcanic bombs: an example from the historical eruption of Azuma–Jododaira volcano, NE Japan
Abstract Vulcanian activity is one of the most common eruption styles of arc andesitic volcanism on Earth. It ejects and deposits volcanic bombs around the source crater. Although paleomagnetic studies of volcanic bombs are limited, such studies can potentially provide more opportunities for high-resolution paleomagnetic dating of volcanic activity. In this study, paleomagnetic dating was applied to large (> 1 m) volcanic bombs around active craters in the Azuma volcano group, NE Japan. Oriented samples were collected from the interior parts of five large volcanic bombs situated on gentle slopes, a few hundred meters from the source crater. More than six core samples were collected from each bomb and all samples were subjected to a range of rock magnetic experiments, including anisotropy of magnetic susceptibility (AMS) and thermal/alternating field demagnetization (THD/AFD) analyses. The Characteristic Remanent Magnetization (ChRM) directions for specimens from all bombs were well-defined, have small α95 (< 2.5º), and are in close agreement with each other. Comparing our measured overall mean direction (Dm = 355.5º, Im = 49.8º, α95 = 1.6º) with modeled geomagnetic field estimates and a reference secular variation curve for this area (using MATLAB-based archaeomagnetic dating tool), we suggest that the volcanic bombs were produced in the historical Meiji period (1893–1895 CE) eruption. In addition, a combination of the data of ChRM, AMS, thermomagnetic analyses, hysteresis measurement, and XRF analysis indicates that the volcanic bombs were derived from a plug of lava in the conduit under the solidification point (ca. 800 °C), but above the Curie point of the titanomagnetite remanence carrier (around 300 °C). We show that volcanic bombs can be powerful for paleomagnetic dating if certain sampling conditions, such as quantity, situation, size and portion are satisfied. Graphical Abstrac