Search

Determining the neuronal circuitry responsible for specific behaviors is a major focus in the field of neurobiology. Activity-dependent immediate early genes (IEGs), transcribed and translated shortly after neurons discharge action potentials, have been used extensively to either identify or gain genetic access to neurons and brain regions involved in such behaviors. By using immunohistochemistry for the protein product of the IEG c-Fos combined with retrograde labeling of specific neuronal populations, precise experimental timing, and identical data acquisition and processing, we present a method to quantitatively identify specific neuronal subpopulations that were active during social encounters. We have previously used this method to show a stronger recruitment of ventral hippocampal neurons that project to the medial prefrontal cortex, compared to those that project to the lateral hypothalamus, following social interactions. After optimization of surgeries for the injection of retrograde tracers, this method will be useful for the identification and mapping of neuronal populations engaged in many different behaviors.

Aquarium pets release is an important vector for invasive species establishment in freshwater ecosystems. Here the perceptions and risk behaviors associated to this vector were evaluated using a survey. Portuguese aquarium hobbyists were interviewed through an on-line survey (Google forms) publicized in 9 web sites connected to this hobby (Facebook pages and internet forums). A Pet Propagule Pressure index (PPP), congregating information regarding pet’s popularity and electivity for discharge, was developed and applied in this study, so that relative comparisons can be made among different pet types (taxa). Additionally, non-metric Multidimensional Scaling (nMDS) was applied to pet owner’s data to identify indicator factors associated with risk behaviors and impacts’ awareness. Results indicated that aquarium pet owners usually only have one pet type, most commonly fish or turtles. Only 8% of the owners admit having discharged pets, being more commonly reported the release of only one pet. This risk behavior is connected mainly to the excessive growth of the pet and consequently lack of space in the aquariums. Pet’s discharge occurs until 100 km of distance from owner’s homes, being very common at distances lower than 1 km. The PPP index developed in this study, indicates the pet types with higher risk of discharge were the turtles and the fishes. Pet owner’s awareness regarding the pet discharges impacts in the environment seems to be lower than other risk groups connected to biological invasions in freshwaters, namely anglers. Pet owners most aware of these impacts were associated to higher education levels and higher experience on this hobby. Our study highlights the needs for more environmental education on particular social groups within aquarium pets’ owners, namely those that have started this activity or have lower education levels, to decrease the biological invasion risks associated to this hobby. Additionally, our findings regarding the patterns and drivers of discharge action itself are useful to model risk invasion, as well as for detection, management and control of these species.

As the final common pathway from the nervous system to muscle, the motor unit transmits an activation signal and transforms it into contractile activity. By varying the number of motor units that are activated for a specific action and the rates at which they discharge action potentials, the nervous system is able to control a range of muscle functions. The contractile properties of muscle comprise its force capacity (strength and power), the rate at which it can develop force (contractile speed), and the duration that it can sustain a specific force (fatigability). We discuss the key neuromuscular determinants for each of these attributes, how they can be measured, and how they can be modified by physical activity. The adaptations selectively involve structures and processes that extend from the cerebral cortex to the connective tissues involved in force transmission from the muscle fibers to the skeleton.

ABSTRACT Aim: Human embryonic stem cell (hESC)-derived motor neurons (MNs) can model neurodegenerative diseases, in other words, for the development of cell-based drug screening assays. However, efficient MN generation is challenging and high level of contamination of undifferentiated cells remains a significant problem when culturing hESC-derived MNs. We describe a protocol for the removal of undifferentiated cells using the DNA synthesis inhibitor arabinofuranosyl cytidine (Ara-C). Materials & methods: hESC-MNs were treated with Ara-C after the last step of differentiation. FACS analysis and fluorescence microscopy were used to identify and quantify MNs. Results: HB9/ChAT-positive live mature MNs were enriched 3.9-times in Ara-C-treated cultures when compared with untreated cells. The Ara-C-treated MNs are electrophysiologically functional and discharge action potentials. Conclusion: Ara-C selection of MNs can be combined with stem cell differentiation protocols to enrich MNs in culture.

The influence of a glow electrical discharge on the wake behind two cylinders was studied. This effect consists in a redistribution of the power in the velocity pulsation spectrum due to the discharge action on fluid flow. To treat this observation, we need a simple model of intermittent turbulent wake in the vicinity of cylinders. A variant of such model has been developed in the form of two coupled van-der-Pole oscillators representing two interacting von Karman vortex streets behind the cylinders. According to the model, the set of the global wake modes and its concurrence are discussed. Accordingly, a mechanism of the glow discharge effect on the cylinders wake has been proposed.

The force exerted by a muscle during a voluntary contraction depends on the number of motor units recruited for the action and the rates at which they discharge action potentials (rate coding). Over most of the operating range of a muscle, the nervous system controls muscle force by varying both motor unit recruitment and rate coding. Except at relatively low forces, however, the control of muscle force depends primarily on rate coding, especially during fast contractions. This review provides five examples of how the modulation of rate coding influences the force exerted by muscle during voluntary actions. The five examples comprise fast contractions, lengthening and shortening contractions, steady isometric contractions, fatiguing contractions, and contractions performed after a change in the daily level of physical activity.

New Findings What is the central question of this study? How long can humans sustain motor unit discharge during a voluntary contraction? What is the main finding and its importance? Human motor units can discharge action potentials for a longer time during a voluntary contraction than can be achieved by intracellular or extracellular current injection of motor neurons with in vivo and in vitro animal preparations. These recordings comprise a previously unexplored range of durations for human motor unit recordings during a continuously sustained isometric recording. The purpose of the study was to determine how long humans could sustain the discharge of single motor units during a voluntary contraction. The discharge of motor units in first dorsal interosseus of subjects (27.8 ± 8.1 years old) was recorded for as long as possible. The task was terminated when the isolated motor unit stopped discharging action potentials, despite the ability of the individual to sustain the abduction force. Twenty-three single motor units were recorded. Task duration was 21.4 ± 17.8 min. When analysed across discharge duration, mean discharge rate (10.6 ± 1.8 pulses s−1) and mean abduction force (5.5 ± 2.8% maximum) did not change significantly (discharge rate, P = 0.119; and abduction force, P = 0.235). In contrast, the coefficient of variation for interspike interval during the initial 30 s of the task was 22.2 ± 6.0% and increased to 31.9 ± 7.0% during the final 30 s (P

It is proposed to carry out pre-mine methane drainage using underground degassing holes made by downhole air hammer drills. The features of downhole air drills are described. The downhole air drill layout with the simple-shape striking part is presented with its pluses and minuses. The researchers point at available options to eliminate the shortcomings. The improved layout of the downhole air hammer drill is suggested. The paper ends with the test data on the prototype air hammer drill, its characteristics and trial drilling results.

The effect of atmospheric-pressure gliding discharge action on an electrolyte solution was studied. The hydrogen peroxide yields in the solutions were defined after the discharge treatment, as well as the pH and electroconductivity values. Gliding discharge was shown to be more effective than glow discharge for H2O2 formation in the electrolyte solution.

The purpose of the study was to determine whether pairs of motor units that discharge action potentials at different rates during isometric contractions exhibit different levels of motor unit synchronization or coherence. Twelve subjects (28.6 +/- 6.1 years) performed isometric contractions at target forces slightly above the recruitment threshold (1.02-20.9%) of an isolated motor unit. Based on audio feedback, subjects maintained a relatively constant discharge rate of the isolated unit for about 80 s. Intramuscular electrodes were used to record the discharge of 47 pairs of motor units at rates that ranged from 8.07 to 13.6 pps. Correlated discharge between pairs of motor units was quantified with the common input strength (CIS) index, k' index, and coherence spectrum. Greater discharge rates across pairs of motor units were predicted (R2 = 0.36, P < 0.001) by higher coherence from 8 to 13 Hz (r = -0.52) and lower coherence from 0 to 4 Hz (r = 0.37). Indexes of motor unit synchronization (CIS and k') were strongly associated with motor unit coherence from 16 to 32 Hz (CIS: R2 = 0.63; k': R2 = 0.4; P = 0.001). The CIS index of motor unit synchronization and the motor unit coherence from 16 to 32 Hz did not vary with discharge rate. In contrast, the k' index of motor unit synchronization declined with discharge rate (r2 = 0.20, P = 0.001). Furthermore, greater discharge rates across pairs of motor units were accompanied by higher motor unit coherence in the 8-13 Hz band and lower motor unit coherence in the 0-4 Hz band. These results demonstrate that differences in discharge rate between pairs of motor units in first dorsal interosseus during low-force, isometric contractions were associated with modulation of the correlation in the discharge times of the two motor units at frequencies less than 15 Hz.

Journal Article, SCOPUS: ar.j, info:eu-repo/semantics/published

Elizabeth Haines1, Robert van Amerongen2, Robert Birkhahn1, Wendy Wen1, Theodore Gaeta11Department of Emergency Medicine, 2Pediatric Emergency Services, New York Methodist Hospital, Brooklyn, NY, USAAbstract: Acute gastroenteritis accounts for 1–2 million annual pediatric emergency department visits in the US. The current literature supports the use of antiemetics, such as ondansetron, in the emergency department, reporting improved oral rehydration, cessation of vomiting, and reduction in the need for intravenous rehydration. However, there remains concern that using these agents may “mask alternative diagnoses” and negatively impact patient care. We present a case series of 29 patients who received a pediatric emergency department discharge action plan which allowed for a dose of ondansetron to be dispensed by the clinician at the time of discharge. Patients were instructed to administer the ondansetron at home for treatment of ongoing nausea and vomiting any time after 6 hours from the time of emergency department discharge. These patients were followed up at 3–5 days following discharge to assess for outcomes. Implications of this discharge action plan and future directions are discussed.Keywords: gastroenteritis, ondansetron, discharge action plan

The result of investigations of the main physical properties of pulse discharges of small energy in water is presented. The main types of discharge action on microorganisms (bacteria, etc.) and chemical substances existing in water are represented in the work. Preliminary data on pure (distilled) water properties appearing after discharge action is represented. In conclusion, a description of an industrial facility which can be used in different technological processes and examples of such facilities in the USA are presented.

BEFORE beginning my paper I wish to take the opportunity to express my appreciation of the honor extended to me in having been asked to deliver a paper before so distinguished a society. It was only with reluctance that I accepted the invitation, for I have nothing new or startling to present to you. However, I will try to describe to you the methods which we have found of practical value in the treatment of malignant disease at the State Institute at Buffalo. 1. Theories of Action Let us first consider briefly the theories of action. These may be summarized as: (1)Ionization, photochemical, or physical theory. This hypothesis assumes the collision of rays with the atomic cell structure, resulting in the formation of beta and secondary gamma rays and, perhaps, some unknown biochemical modification of the protoplasm. (2)Thermochemical action, as exemplified by the point heat theory of Dessauer. (3)Discharge action in which absorbed radiation serves to neutralize or discharge excessive accumulated tissue ch...

The nucleus locus coeruleus (LC) is a group of neurons situated close to the floor of the fourth ventricle at the upper border of the pons. The cells of the rat LC are homogeneous by certain criteria. Virtually all the cells contain noradrenaline and its synthesizing enzymes (Dahlstrom and Fuxe, 1964; Pickel et al., 1979), and, in the anesthetized animal, they all discharge action potentials at a rather regular and slow rate (0.5 to 2 Hz) (Korf et al., 1974).