Electrical Recording from the Contractile Ciliate Zoothamnium Geniculatum Ayrton

1979 ◽  
Vol 83 (1) ◽  
pp. 159-167
Author(s):  
R. B. MORETON ◽  
W. B. AMOS
Keyword(s):  
Body Surface ◽  
Complex Form ◽  
Spherical Body ◽  
Mechanical Stimulus ◽  
The Body ◽  
Negative Potential ◽  
Contractile Vacuole ◽  
Ciliate Protozoan ◽  
Electrical Recording

1. The spherical body (200 μm in diameter) of this ciliate protozoan was easily immobilized on a suction pipette and penetrated with glass micro electrodes. 2. No recordings could be made from the contractile stalk, but in the body a negative potential of 30.3 ± 125 mV was observed. 3. Approximately 9 ms after the onset of a mechanical stimulus, a rapid depolarization was observed. This was apparently simultaneous throughout the body surface. The amplitude was 38.9 ± 13.7 mV. Recordings with aphotomultiplier showed that contraction of the stalk began 10 ms later. 4. A slower depolarization of complex form was observed during systole of the contractile vacuole.

The Physiology of Contractile Vacuoles

1960 ◽  
Vol 37 (1) ◽  
pp. 73-82
Author(s):  
J. A. KITCHING ◽  
J. E. PADFIELD ◽  
M. H. ROGERS
Keyword(s):  
Body Surface ◽  
Normal Activity ◽  
The Body ◽  
Contractile Vacuole ◽  
Diffusion Constants ◽  
Contractile Vacuoles

1. The suctorian Discophrya collini (Root) has been subjected to D2O-H2O mixtures containing up to 99.7% D2O. 2. In 25% D2O or over there is a rapid but temporary shrinkage of the body. This shrinkage is difficult to estimate owing to the wrinkling of the body surface, but amounts to at least 10% in the undiluted (99.7%)D2O. 3. During the period of temporary shrinkage the contractile vacuole ceases activity. Normal activity is resumed when the normal volume is regained. In concentrations of D2O too low to cause shrinkage there is a temporary fall in the rate of vacuolar output. 4. Return to H2O leads to a brief but often very considerable rise in vacuolar output. 5. It is concluded that D2O penetrates less rapidly than H2O. A difference of at least 10% in the diffusion constants in the membrane would be required to explain our results. We cannot exclude this as unreasonable from our data, although an explanation based on differences in the equilibrium properties of D2O and H2O might also be invoked.

The Elicitation of the Predatory Labial Strike of Dragonfly Larvae in Response to a Purely Mechanical Stimulus

1983 ◽  
Vol 107 (1) ◽  
pp. 391-404 ◽  
Author(s):  
MASAMICHI KANOU ◽  
TATEO SHIMOZAWA
Keyword(s):  
Body Surface ◽  
Visual Information ◽  
Visual Cues ◽  
Mechanical Stimulus ◽  
Water Velocity ◽  
Water Jet ◽  
The Body ◽  
Head Orientation ◽  
Jet Nozzle ◽  
Higher Sensitivity

The predatory labial strike of dragonfly (Aeschna) larvae could be elicited by an artificial water jet stimulus. The larvae showed fair prey-catching ability even when visually deprived, whereas when deprived of mechanosensory and visual information, the ability decreased sharply. Also, immobilized prey were unable to elicit a strike even from intact larvae. The percentage of labial strike (PLS) increased in proportion to the logarithm of the water velocity at the body surface. Animals starved for 1 day or more showed higher PLS than satiated ones. In addition to the water velocity, the movement of the jet nozzle (temporary change in the velocity) was also important in eliciting the labial strike. Although repetitive stimuli resulted in a rapid habituation of the labial strike, the second stimulus in a series was always the most effective: an arousal state to the newness was observed. The anterior parts of the body surface (including the legs) showed higher sensitivity of PLS to the water jet stimulus, whereas the posterior parts elicited responses other than the labial strike: turning, head orientation and the setting of a posture. These results explain nocturnal predation of larvae and predation in turbid pond beds where visual cues will be unavailable.

scholarly journals The Physiology Of Contractile Vacuoles

1936 ◽  
Vol 13 (1) ◽  
pp. 11-27
Author(s):  
J. A. KITCHING
Keyword(s):  
Cell Membrane ◽  
Body Surface ◽  
Salt Concentration ◽  
Sea Water ◽  
Cane Sugar ◽  
The Body ◽  
Contractile Vacuole ◽  
Body Volume ◽  
Oxidative Process ◽  
Low Concentrations

1. There was no change in the body volume of marine Peritricha subjected to reductions in the salt concentration of the medium, so long as the osmotic pressure of the medium was kept constant by the addition of urea, glycerol, or cane-sugar. In mixtures of isotonic non-electrolytes with sea water the rate of vacuolar output was decreased--more so in the case of urea than of glycerol. It is concluded that the cell membrane is relatively impermeable to urea, glycerol, and cane-sugar, and also to neutral salts. 2. Excretory substances could not be produced in sufficient quantity to attract water into the contractile vacuole by osmosis at the rate observed. The process of diastole therefore involves "secretion" of water by the vacuolar walls. 3. Cyanide and sulphide in very low concentrations rapidly caused a great reduction in the rate of output of the contractile vacuole of marine Peritricha. In the case of cyanide this effect was rapidly reversible. Alcohols and urethane only decreased the rate of vacuolar output when present in much higher concentrations. It is suggested that possibly vacuolar activity depends directly on an oxidative process. 4. When marine Peritricha were transferred from dilute sea water to dilute sea water of the same concentration+cyanide M/200 or M/500 (the pH being carefully controlled), the contractile vacuole was completely or almost completely stopped, and the body increased in volume. When the organism was transferred back to dilute sea water of the same concentration without cyanide, the contractile vacuole became active again and the body decreased in volume until a new steady value was attained which was rather below the value in dilute sea water before cyanide treatment. 5. The increase in body volume consequent on treatment with cyanide was greater the more dilute was the sea water. For sea water of concentrations of 100-75 per cent, no swelling was detectable when the organism was treated with cyanide. 6. The rate of output of the contractile vacuole is sufficiently great to account for the decrease in body volume during recovery from cyanide. 7. The permeability of the body surface to water is estimated as 0.05-0.10 cubic micra per square micron per atmosphere per minute.

The Role of Computer Modeling in Electrocardiography

1990 ◽  
Vol 29 (04) ◽  
pp. 282-288 ◽  
Author(s):  
A. van Oosterom
Keyword(s):  
Electrical Activity ◽  
Computer Modeling ◽  
Body Surface ◽  
Electrical Current ◽  
The Body ◽  
Volume Conductor ◽  
Current Generator ◽  
Cardiac Electrical Activity ◽  
Source Models

AbstractThis paper introduces some levels at which the computer has been incorporated in the research into the basis of electrocardiography. The emphasis lies on the modeling of the heart as an electrical current generator and of the properties of the body as a volume conductor, both playing a major role in the shaping of the electrocardiographic waveforms recorded at the body surface. It is claimed that the Forward-Problem of electrocardiography is no longer a problem. Several source models of cardiac electrical activity are considered, one of which can be directly interpreted in terms of the underlying electrophysiology (the depolarization sequence of the ventricles). The importance of using tailored rather than textbook geometry in inverse procedures is stressed.

The use of Body Surface Index as a Better Clinical Health indicators Compare to Body Mass Index and Body Surface Area for Clinical Application

2018 ◽  
pp. 131-136
Author(s):  
Shirazu I. ◽  
Theophilus. A. Sackey ◽  
Elvis K. Tiburu ◽  
Mensah Y. B. ◽  
Forson A.
Keyword(s):  
Surface Area ◽  
Body Surface Area ◽  
Clinical Application ◽  
Body Surface ◽  
Body Height ◽  
Health Indicators ◽  
The Body ◽  
Body Parameters ◽  
The Relationship ◽  
Individual Body

The relationship between body height and body weight has been described by using various terms. Notable among them is the body mass index, body surface area, body shape index and body surface index. In clinical setting the first descriptive parameter is the BMI scale, which provides information about whether an individual body weight is proportionate to the body height. Since the development of BMI, two other body parameters have been developed in an attempt to determine the relationship between body height and weight. These are the body surface area (BSA) and body surface index (BSI). Generally, these body parameters are described as clinical health indicators that described how healthy an individual body response to the other internal organs. The aim of the study is to discuss the use of BSI as a better clinical health indicator for preclinical assessment of body-organ/tissue relationship. Hence organ health condition as against other body composition. In addition the study is `also to determine the best body parameter the best predict other parameters for clinical application. The model parameters are presented as; modeled height and weight; modelled BSI and BSA, BSI and BMI and modeled BSA and BMI. The models are presented as clinical application software for comfortable working process and designed as GUI and CAD for use in clinical application.

Mannose-binding C-type lectins as defense molecules on the body surface of the sea urchin Pseudocentrotus depressus

2021 ◽  
Vol 116 ◽  
pp. 103915
Author(s):  
Chihiro Iiyama ◽  
Fuyu Yoneda ◽  
Masaya Tsutsumi ◽  
Shigeyuki Tsutsui ◽  
Osamu Nakamura
Keyword(s):  
Sea Urchin ◽  
Body Surface ◽  
The Body ◽  
Mannose Binding ◽  
Defense Molecules

Development and Validation of a New Scoring Tool to Evaluate the Clinical Evolution of Adult Patients with Nonsegmental Vitiligo

Dermatology ◽  
2021 ◽  
pp. 1-9
Author(s):  
María Luisa Peralta-Pedrero ◽  
Denisse Herrera-Bringas ◽  
Karla Samantha Torres-González ◽  
Martha Alejandra Morales-Sánchez ◽  
Fermín Jurado Santa-Cruz ◽  
...  
Keyword(s):  
Body Surface ◽  
Task Force ◽  
Intraclass Correlation ◽  
The Body ◽  
Response To Treatment ◽  
Similar Response ◽  
Clinical Evolution ◽  
Wide Range ◽  
Patient Reported ◽  
Extreme Groups

<b><i>Background:</i></b> Vitiligo has an unpredictable course and a variable response to treatment. Furthermore, the improvement of some vitiligo lesions cannot be considered a guarantee of a similar response to the other lesions. Instruments for patient-reported outcome measures (PROM) can be an alternative to measure complex constructions such as clinical evolution. <b><i>Objective:</i></b> The aim of this study was to validate a PROM that allows to measure the clinical evolution of patients with nonsegmental vitiligo in a simple but standardized way that serves to gather information for a better understanding of the disease. <b><i>Methods:</i></b> The instrument was created through expert consensus and patient participation. For the validation study, a prospective cohort design was performed. The body surface area affected was measured with the Vitiligo Extension Score (VES), the extension, the stage, and the spread by the evaluation of the Vitiligo European Task Force assessment (VETFa). Reliability was determined with test-retest, construct validity through hypothesis testing, discriminative capacity with extreme groups, and response capacity by comparing initial and final measurements. <b><i>Results:</i></b> Eighteen semi-structured interviews and 7 cognitive interviews were conducted, and 4 dermatologists were consulted. The instrument Clinical Evolution-Vitiligo (CV-6) was answered by 119 patients with a minimum of primary schooling. A wide range was observed in the affected body surface; incident and prevalent cases were included. The average time to answer the CV-6 was 3.08 ± 0.58 min. In the test-retest (<i>n</i> = 53), an intraclass correlation coefficient was obtained: 0.896 (95% CI 0.82–0.94; <i>p</i> &#x3c; 0.001). In extreme groups, the mean score was 2 (2–3) and 5 (4–6); <i>p</i> &#x3c; 0.001. The initial CV-6 score was different from the final one and the change was verified with VES and VETFa (<i>p</i> &#x3c; 0.05, <i>n</i> = 92). <b><i>Conclusions:</i></b> The CV-6 instrument allows patient collaboration, it is simple and brief, and it makes it easier for the doctor to focus attention on injuries that present changes at the time of medical consultation.

scholarly journals Inter-body coupling in electro-quasistatic human body communication: theory and analysis of security and interference properties

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mayukh Nath ◽  
Shovan Maity ◽  
Shitij Avlani ◽  
Scott Weigand ◽  
Shreyas Sen
Keyword(s):  
Channel Capacity ◽  
Body Surface ◽  
Human Body ◽  
Communication Theory ◽  
The Body ◽  
Body Area ◽  
Theoretical Understanding ◽  
Communication Modality ◽  
Conductive Properties ◽  
Human Body Communication

AbstractRadiative communication using electromagnetic fields is the backbone of today’s wirelessly connected world, which implies that the physical signals are available for malicious interceptors to snoop within a 5–10 m distance, also increasing interference and reducing channel capacity. Recently, Electro-quasistatic Human Body Communication (EQS-HBC) was demonstrated which utilizes the human body’s conductive properties to communicate without radiating the signals outside the body. Previous experiments showed that an attack with an antenna was unsuccessful at a distance more than 1 cm from the body surface and 15 cm from an EQS-HBC device. However, since this is a new communication modality, it calls for an investigation of new attack modalities—that can potentially exploit the physics utilized in EQS-HBC to break the system. In this study, we present a novel attack method for EQS-HBC devices, using the body of the attacker itself as a coupling surface and capacitive inter-body coupling between the user and the attacker. We develop theoretical understanding backed by experimental results for inter-body coupling, as a function of distance between the subjects. We utilize this newly developed understanding to design EQS-HBC transmitters that minimizes the attack distance through inter-body coupling, as well as the interference among multiple EQS-HBC users due to inter-body coupling. This understanding will allow us to develop more secure and robust EQS-HBC based body area networks in the future.

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