scholarly journals A Comparative Study Of The Double Motor Innervation In Marine Crustaceans

1938 ◽  
Vol 15 (1) ◽  
pp. 18-31
Author(s):  
C. A. G. WIERSMA ◽  
A. VAN HARREVELD
Keyword(s):  
Mechanical Response ◽  
Time Interval ◽  
Muscle Action ◽  
Motor Innervation ◽  
Action Current ◽  
Marine Crustaceans ◽  
First Case ◽  
Slow Contraction ◽  
Thick Fibre ◽  
Stimulation Of

A double motor innervation has been shown for several muscles of marine crustaceans. The adductors of the claws of Randallia and Blepharipoda and the adductor of the dactylopodite of the walking leg of Cancer were studied physiologically. The two motor axons which innervate these muscles have a different diameter (ratio 1.4: 1). Stimulation of the thick fibre causes a response, which, though it is not always faster than the response of the thin fibre, must be considered as a "fast" contraction. In Randallia and in Blepharipoda the slow contraction is higher than the fast with frequencies of less than ± 50 per sec., in Cancer with frequencies less than 100 per sec. The action currents of the two kinds of contraction are different. Both show facilitation, but under the same conditions of stimulation the fast-action currents are higher. The first stimulus of the thick fibre causes an action current top which is clearly distinguishable, the action currents of the slow contraction show up only after a number of stimuli. Even when the mechanical reaction on stimulation of the thick fibre is smaller than on similar stimulation of the thin fibre, the action currents are higher in the first case. A single impulse in the thick fibre does not cause a contraction, but sets up a muscle-action current. The chronaxie of this action current in Blepharipoda and Randallia is 0.8σ and is about the same as that found for the action current of the nerve. Two impulses in the thick fibre may cause a mechanical response, as is shown by summation experiments. The pseudo-chronaxie of this contraction was measured as 3.5 σ. The second action current shows facilitation, when it follows the first within 1 sec.; a mechanical reaction results with summation intervals of two stimuli of less than 10σ. The facilitation of the action current increases with decrease of the time interval between the two impulses; with the shortest intervals that give summation the resulting action current is a smooth high spike.

scholarly journals CHEMICAL CHANGES IN THE ADDUCTOR MUSCLE OF THE CHELIPED OF THE CRAYFISH IN RELATION TO THE DOUBLE MOTOR INNERVATION

1938 ◽  
Vol 22 (2) ◽  
pp. 193-206 ◽  
Author(s):  
W. R. Bergren ◽  
C. A. G. Wiersma
Keyword(s):  
Lactic Acid ◽  
Adductor Muscle ◽  
Mechanical Action ◽  
Phosphate Content ◽  
Motor Innervation ◽  
Chemical Changes ◽  
Maximum Extent ◽  
Mechanical Effects ◽  
Slow Contraction ◽  
Stimulation Of

An investigation has been made of the phosphate and lactic acid changes in the adductor muscle of the cheliped of the crayfish Cambarus clarkii upon stimulation of the isolated axons for the fast and slow contractions at determined frequencies. The data obtained point to the following conclusions: 1. When the mechanical effects of the two types of contraction are the same, the chemical changes are of the same order. If the mechanical effects are different, the chemical changes likewise are not equivalent. This is especially to be seen in the case of stimulation at 50 shocks per second: a slowly rising, long continued, strong slow contraction takes place with no apparent change in the phosphate content; a quickly rising fast contraction occurs with a large increase in the phosphate. 2. Since equivalent chemical changes accompany equivalent mechanical action, the two types of contraction do not differ in the essential mechanism of the chemical changes involved, and only one type of contractile substance is present. 3. Even when a contraction has taken place to the maximum extent obtainable, only enough phosphate is found to correspond to one-fifth to one-third of the available phosphagen.

scholarly journals The Motor Innervation of a Triply Innervated Crustacean Muscle

1939 ◽  
Vol 16 (4) ◽  
pp. 398-402
Author(s):  
A. VAN HARREVELD
Keyword(s):  
Mechanical Injury ◽  
Muscle Fibres ◽  
Motor Innervation ◽  
Nerve Fibres ◽  
Crustacean Muscle ◽  
Conduction Process ◽  
Slow Contraction ◽  
Stimulation Of

The crustacean muscle is extremely sensitive to mechanical injury. This is due to the fact that the muscle fibres are innervated by a feltwork of nerve fibres which surrounds them. Apparéntly, there is a lack of a muscular conduction process in these muscles. Contractions have been observed in the same muscle fibres during stimulation of the axon for the fast contraction as well as during stimulation of the fibre for the slow contraction.

scholarly journals The STAFF-DWP wave instrument on the DSP equatorial spacecraft: description and first results

2005 ◽  
Vol 23 (8) ◽  
pp. 2785-2801 ◽  
Author(s):  
N. Cornilleau-Wehrlin ◽  
H. St. Alleyne ◽  
K. H. Yearby ◽  
B. de la Porte de Vaux ◽  
A. Meyer ◽  
...  
Keyword(s):  
Electromagnetic Waves ◽  
Broad Band ◽  
Temporal Analysis ◽  
Time Interval ◽  
Magnetic Fluctuations ◽  
Quiet Time ◽  
Waveform Data ◽  
Power Intensity ◽  
First Case ◽  
First Results

Abstract. The STAFF-DWP wave instrument on board the equatorial spacecraft (TC1) of the Double Star Project consists of a combination of 2 instruments which are a heritage of the Cluster mission: the Spatio-Temporal Analysis of Field Fluctuations (STAFF) experiment and the Digital Wave-Processing experiment (DWP). On DSP-TC1 STAFF consists of a three-axis search coil magnetometer, used to measure magnetic fluctuations at frequencies up to 4 kHz and a waveform unit, up to 10 Hz, plus snapshots up to 180 Hz. DWP provides several onboard analysis tools: a complex FFT to fully characterise electromagnetic waves in the frequency range 10 Hz-4 kHz, a particle correlator linked to the PEACE electron experiment, and compression of the STAFF waveform data. The complementary Cluster and TC1 orbits, together with the similarity of the instruments, permits new multi-point studies. The first results show the capabilities of the experiment, with examples in the different regions of the magnetosphere-solar wind system that have been encountered by DSP-TC1 at the beginning of its operational phase. An overview of the different kinds of electromagnetic waves observed on the dayside from perigee to apogee is given, including the different whistler mode waves (hiss, chorus, lion roars) and broad-band ULF emissions. The polarisation and propagation characteristics of intense waves in the vicinity of a bow shock crossing are analysed using the dedicated PRASSADCO tool, giving results compatible with previous studies: the broad-band ULF waves consist of a superimposition of different wave modes, whereas the magnetosheath lion roars are right-handed and propagate close to the magnetic field. An example of a combined Cluster DSP-TC1 magnetopause crossing is given. This first case study shows that the ULF wave power intensity is higher at low latitude (DSP) than at high latitude (Cluster). On the nightside in the tail, a first wave event comparison - in a rather quiet time interval - is shown. It opens the doors to future studies, such as event timing during substorms, to possibly determine their onset location.

Cross-Innervation of the Thyroarytenoid Muscle by a Branch from the External Division of the Superior Laryngeal Nerve

1997 ◽  
Vol 106 (7) ◽  
pp. 594-598 ◽  
Author(s):  
Sina Nasri ◽  
Joel A. Sercarz ◽  
Pouneh Beizai ◽  
Young-Mo Kim ◽  
Ming Ye ◽  
...  
Keyword(s):  
Vocal Fold ◽  
Superior Laryngeal Nerve ◽  
Laryngeal Nerve ◽  
Spasmodic Dysphonia ◽  
Clinical Implications ◽  
Motor Innervation ◽  
Vocal Fold Vibration ◽  
Adductor Spasmodic Dysphonia ◽  
Thyroarytenoid Muscle ◽  
Stimulation Of

The neuroanatomy of the larynx was explored in seven dogs to assess whether there is motor innervation to the thyroarytenoid (TA) muscle from the external division of the superior laryngeal nerve (ExSLN). In 3 animals, such innervation was identified. Electrical stimulation of microelectrodes applied to the ExSLN resulted in contraction of the TA muscle, indicating that this nerve is motor in function. This was confirmed by electromyographic recordings from the TA muscle. Videolaryngostroboscopy revealed improvement in vocal fold vibration following stimulation of the ExSLN compared to without it. Previously, the TA muscle was thought to be innervated solely by the recurrent laryngeal nerve. This additional pathway from the ExSLN to the TA muscle may have important clinical implications in the treatment of neurologic laryngeal disorders such as adductor spasmodic dysphonia.

Motor innervation within supernumerary legs of cockroaches

1975 ◽  
Vol 63 (2) ◽  
pp. 497-503
Author(s):  
J. Westin ◽  
J. M. Camhi
Keyword(s):  
Motor Innervation ◽  
Stimulation Of

1. Clusters of legs having prothoracic and metathoracic origins were grown from the metathoracic coxa of the cockroach. 2. Or occasionally two, of the three major nerves innervating the cockroach leg. 3. Stimulation of a particular leg nerve (no. 3, 5 or 6) evoked movement at the same joints and in the same directions in a leg having only one nerve as in a normal leg. 4. Stimulation of a particular metathoracic nerve generally produced the same movements in a prothoracic leg transplanted to the metathoracic site as it did in a regenerated or intact metathoracic leg.

scholarly journals Reversible Actuation Ability upon Light Stimulation of the Smart Systems with Controllably Grafted Graphene Oxide with Poly (Glycidyl Methacrylate) and PDMS Elastomer: Effect of Compatibility and Graphene Oxide Reduction on the Photo-Actuation Performance

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 832 ◽  
Author(s):  
Josef Osicka ◽  
Miroslav Mrlik ◽  
Marketa Ilcikova ◽  
Barbora Hanulikova ◽  
Pavel Urbanek ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Glycidyl Methacrylate ◽  
Mechanical Response ◽  
Dynamic Mechanical Properties ◽  
Light Stimulation ◽  
Smart Systems ◽  
Elastomeric Matrix ◽  
Chain Mobility ◽  
Angle Measurements ◽  
Stimulation Of

This study is focused on the controllable reduction of the graphene oxide (GO) during the surface-initiated atom transfer radical polymerization technique of glycidyl methacrylate (GMA). The successful modification was confirmed using TGA-FTIR analysis and TEM microscopy observation of the polymer shell. The simultaneous reduction of the GO particles was confirmed indirectly via TGA and directly via Raman spectroscopy and electrical conductivity investigations. Enhanced compatibility of the GO-PGMA particles with a polydimethylsiloxane (PDMS) elastomeric matrix was proven using contact angle measurements. Prepared composites were further investigated through the dielectric spectroscopy to provide information about the polymer chain mobility through the activation energy. Dynamic mechanical properties investigation showed an excellent mechanical response on the dynamic stimulation at a broad temperature range. Thermal conductivity evaluation also confirmed the further photo-actuation capability properties at light stimulation of various intensities and proved that composite material consisting of GO-PGMA particles provide systems with a significantly enhanced capability in comparison with neat GO as well as neat PDMS matrix.

scholarly journals Observational study on healthcare workers protection in the angiographic suite during the SARS-CoV-2 pandemic: before and during vax era

2021 ◽  
Author(s):  
Massimiliano Cernigliaro ◽  
Davide Negroni ◽  
Miriana Sassone ◽  
Andrea Paladini ◽  
Alessandro Carriero ◽  
...  
Keyword(s):  
Healthcare Workers ◽  
Daily Activities ◽  
Radiology Department ◽  
Morbidity Rate ◽  
Time Interval ◽  
First Case ◽  
Working Shift ◽  
Cleaning Procedures ◽  
Interventional Radiology Department ◽  
New Mutations

Background: Since the first case of Coronavirus Disease 2019 (COVID-19) in Italy, all the hospital facilities had to reform their daily activities. Amidst them, the Interventional Radiology Department in the “Azienda Ospedaliera Universitaria” of Novara (Italy) had to create a dedicated protocol for the patent’s management during the pandemic.Design and Methods: The time interval between February 2020 and March 2021 was divided into three different periods and we reported the evolution of our safety protocol, the changes in our daily activities and the rates of Sars-CoV-2 infection among the healthcare workers (HCW) of the Angiographic Suite. Personnel who had positive partners/family members or who had established close contacts of another nature outside the workplace were excluded from the study, in order to reduce any bias.Results: A total of 35 HCWs served in 355 patient procedures on Sars-CoV-2 positive patients from February 2020 to March 2021. During the year there was a reduction in the morbidity rate first from 7.9% to 1.4% and then currently reaching 0%.Conclusions: Dedicated routes, elevators, establishing Filter Areas and a clear demarcation between clean and contaminated areas, Dressing and undressing procedures, Cleaning procedures and the obligation to always wear a surgical mask during the working shift are essential to prevent in-hospital infection. The vaccines’ arrival seems to further reduce the risk for healthcare workers, but it is still necessary to take docile precautions in view of the new mutations of the virus.

A Lepidopteran Saline: Effects of Inorganic Cation Concentrations on Sensory, Reflex and Motor Responses in a Herbivorous Insect

1966 ◽  
Vol 44 (1) ◽  
pp. 163-175 ◽  
Author(s):  
R. DE G. WEEVERS
Keyword(s):  
Divalent Cations ◽  
Herbivorous Insect ◽  
Muscle Action ◽  
Photometric Analysis ◽  
Action Current ◽  
Inorganic Cation ◽  
Muscle Action Potential ◽  
Muscle Receptors ◽  
Synthetic Media

1. The inorganic cations in the haemolymph of Antheræa pernyi larvae and pupae were analysed by flame photometry. 2. Synthetic media based on these analyses were compared with haemolymph in their effects on the muscle action potential and on the response of the dorsal muscle receptors to a standard stretch. 3. The best match with haemolymph was obtained in all cases with concentrations of divalent cations considerably below the values found by flame photometric analysis. Binding to haemolymph proteins is probably not the major factor responsible for lowering the ionic activities of calcium and magnesium. 4. The role of magnesium in neuromuscular transmission is discussed. It is concluded that in phytophagous Lepidoptera this ion may carry a proportion of the muscle action current.

A Case of Secretory Carcinoma in a Patient With a History of Contralateral Medullary Carcinoma

2022 ◽  
Vol 2 (1) ◽  
pp. 87-92
Author(s):  
RITA STEFANUCCI ◽  
DOMIZIANA SANTUCCI ◽  
SILVIA MARIA ROSSI ◽  
MATTEO SAMMARRA ◽  
ELIODORO FAIELLA ◽  
...  
Keyword(s):  
Ductal Carcinoma ◽  
Medullary Carcinoma ◽  
Caucasian Woman ◽  
Time Interval ◽  
Imaging Features ◽  
Secretory Carcinoma ◽  
Infiltrating Ductal Carcinoma ◽  
First Case ◽  
Medullary Cancer ◽  
History Of

Background: Secretory and medullary carcinomas of the breast are rare subtypes of infiltrating ductal carcinoma. The different histological behavior of medullary and secretory carcinomas is correlated with different imaging features on mammography, ultrasound, and magnetic resonance imaging. Case Report: We report the case of a Caucasian woman in which both subtypes of tumors were diagnosed in an 8-year time interval and evaluate, in antithesis, histopathological and imaging aspects of medullary and secretory carcinoma. Conclusion: To our knowledge, this is the first case reported in literature of secretory carcinoma with a complete imaging tumor evaluation in a patient with a previous contralateral medullary cancer.

Expansion and Contraction of the Oral Disc in the Sea Anemone Tealia Felina

1972 ◽  
Vol 57 (3) ◽  
pp. 633-649
Author(s):  
I. D. MCFARLANE ◽  
I. D. LAWN
Keyword(s):  
Recovery Period ◽  
Stimulus Frequency ◽  
Sensory Response ◽  
Frequency Range ◽  
Oral Disc ◽  
Nerve Net ◽  
Slow Contraction ◽  
Slow Onset ◽  
Radial Muscle ◽  
Stimulation Of

1. Electrical stimulation of the SS 1 of Tealia felina causes inhibition of spontaneousactivity and increase in length of oral disc radial muscle preparations. This response is elicited over a wide stimulus frequency range (1 every 2 sec to 1 every 30 sec). The response shows a slow onset and a long recovery period. 2. Stimulation of the nerve net at frequencies between 1 shock every 5 sec and 1 shock every 20 sec produces slow contraction. The radials also show fast contractions to shocks less than 2 sec apart. 3. Dissolved food substances excite the SS 1 in the column. The sensory response to application of food extract to a small area of the column shows evidence of sensory adaptation. 4. These observations are related to the pre-feeding response of Tealia and a model for oral disc expansion is described.

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