scholarly journals Attachment of Paramecium to polystyrene surfaces: a model system for the analysis of sexual cell recognition and nuclear activation

1982 ◽  
Vol 58 (1) ◽  
pp. 185-199
Author(s):  
A. Kitamura
Keyword(s):  
Temperature Dependent ◽  
Polystyrene Surface ◽  
Nuclear Activation ◽  
Attachment Sites ◽  
Hydrophilic Nature ◽  
Ca Ions ◽  
Sexual Recognition ◽  
Conjugation Process ◽  
The Relationship ◽  
I Cells

In the ciliate Paramecium caudatum, only mating-reactive cells can attach to the polystyrene surface of Petri dishes. The attachment of mating-reactive cells occurs exclusively at the tips of ventrally located cilia (mating-reactive cilia) and appears to involve a hydrophobic interaction. An increase in the hydrophilic nature of the polystyrene surface following treatment with sulphuric acid results in the loss of attachment of reactive cells. The presence or absence of Ca ions and varying the ionic strength of the medium have no effect upon attachment. Although attachment reactivity is closely correlated with mating reactivity, the attachment sites appear distinct from the mating recognition sites, as suggested by the following experimental results: (I) cells that lose mating reactivity following treatment with trypsin are still able to attach to the polystyrene surface; (2) the attachment of cells appears temperature-dependent over a range where mating reactivity remains uneffected; (3) mating reactivity is quickly lost as a result of attachment to the surface of the dish. While the mechanism of attachment is not the same as sexual recognition, the attachment to the polystyrene surface initiates the early stages of the conjugation process. Cells that attach show micronuclear migration while unattached cells do not. The maximum rate of micronuclear migration occurs approximately 30 min after attachment. Meiosis does not occur following migration in the attached cells as in cells that are sexually mating. The relationship between the mating substance and the attachment substance is discussed, while the utilization of the attachment phenomenon for other experimental procedures is proposed.

Variations in magnetic properties of Mexican serpentinites and related micro-textures 

2021 ◽  
Author(s):  
Sandra B. Ramírez-García ◽  
Luis M. Alva-Valdivia
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Anisotropy Of Magnetic Susceptibility ◽  
Ultramafic Rocks ◽  
Magnetic Carrier ◽  
Temperature Dependent ◽  
Geochemical Studies ◽  
The Relationship ◽  
Magnetite Formation

<p>Magnetite formation of serpentinized ultramafic rocks leads to variations in the magnetic properties of serpentinites; however, magnetite precipitation is still on debate.</p><p>In this work, we analyzed 60 cores of ultramafic rocks with a variety of serpentinization degrees. These rocks belong to the ultramafic-mafic San Juan de Otates complex in Guanajuato, Mexico. Geochemical studies have been previously conducted, enabling us to compare changes in the magnetic properties against the chemical variations generated by the serpentinization process. By studying the density and magnetic properties such as anisotropy of magnetic susceptibility, hysteresis curves as well as magnetic and temperature-dependent susceptibility and, we were able to identify the relationship between magnetic content and serpentinization degree, the predominant magnetic carrier, and to what extent the magnetite grain size depends on the serpentinization.  Variations in these parameters allowed us to better constrain the temperature at which serpentinization occurred, the generation of other Fe-rich phases such as Fe-brucite and/or Fe-rich serpentine as well as distinctive rock textures formed at different serpentinization degrees.</p>

scholarly journals The influence of temperature on methane adsorption in coal: A review and statistical analysis

2019 ◽  
Vol 37 (9-10) ◽  
pp. 745-763 ◽  
Author(s):  
Zhijun Wang ◽  
Xiaojuan Wang ◽  
Weiqin Zuo ◽  
Xiaotong Ma ◽  
Ning Li
Keyword(s):  
Coalbed Methane ◽  
Methane Adsorption ◽  
Gas Content ◽  
Future Research ◽  
Temperature Dependent ◽  
Current State ◽  
Influence Of Temperature On ◽  
State Of Research ◽  
Increasing Temperature ◽  
The Relationship

The capacity of coal to adsorb methane is greatly affected by temperature and, in recent years, temperature-dependent adsorption has been studied by many researchers. Even so, comprehensive conclusions have not been reached and conflicting experimental results are common. This paper reviews the current state of research regarding the temperature-dependent adsorption of methane in coal and catalogs the conclusions from experiments conducted on that subject by 28 researchers, as published between 1995 and 2017. Probability theory and statistics are used to show that the conclusion generally accepted by most researchers is that the amount of methane adsorbed by coal decreases with increasing temperature. It is highly likely that the Langmuir volume decreases as the temperature rises, and it is also probable that the Langmuir pressure increases at higher temperatures. Equations are presented that express the relationships between methane adsorption, Langmuir volume, Langmuir pressure, and temperature. Future research should be directed toward determining the relationship between Langmuir pressure and temperature. The results of the study presented herein provide a theoretical basis for predicting the gas content in coal seams and improving the efficiency of coalbed methane development.

Screw in Lisfranc Ligament

2020 ◽  
pp. 193864002091344
Author(s):  
Stephen Sierra ◽  
Vinod K. Panchbhavi
Keyword(s):  
Case Reports ◽  
Average Distance ◽  
Healing Process ◽  
Interosseous Ligament ◽  
Screw Hole ◽  
Attachment Sites ◽  
Medial Cuneiform ◽  
Second Metatarsal ◽  
Relationship Of ◽  
The Relationship

Background. Injury to the Lisfranc interosseous ligament is currently managed with a screw. However, this can potentially further disrupt the ligament. The objective of this study was to observe the proximity of the screw or disruption it can cause at the ligament attachment sites. Methods. Twenty-three feet were studied. A 40-mm, 4.0, partially threaded, cannulated screw was inserted from the base of the second metatarsal into the medial cuneiform. The relationship of the ligament attachment sites to the screw hole were measured. Results. The screw hole contacted at least 1 of the ligament attachment sites in 20 of the 23 feet. The screw hole fully penetrated it in 7 feet, partially disrupted it in 4 feet, and had less than or equal to 1 mm of contact in 9 feet. There was no contact with either of the attachment sites in 3 feet, with an average distance of 1.5 mm separating them. Conclusion. Our results show the proximity of the ligament to the screw and the disruption that can result from its insertion. This is clinically relevant as some amount ligamentous disruption is likely to occur with insertion of the “Lisfranc screw,” which may interfere with its healing process. Levels of Evidence: Level V: Expert opinion includes case reports and technique tips

Temperature-dependent reproduction and survival of Gyrodactylus salaris Malmberg, 1957 (Platyhelminthes: Monogenea) on Atlantic salmon (Salmo salar L.)

Parasitology ◽  
1991 ◽  
Vol 102 (1) ◽  
pp. 105-112 ◽  
Author(s):  
P. A. Jansen ◽  
T. A. Bakke
Keyword(s):  
Atlantic Salmon ◽  
Water Temperature ◽  
Salmo Salar ◽  
Temperature Dependent ◽  
Survival And Reproduction ◽  
Two Temperatures ◽  
The Mean ◽  
Relationship Of ◽  
The Relationship ◽  
Capacity For Increase

SUMMARYThe relationship of survival and reproduction of Gyrodactylus salaris Malmberg on the Atlantic salmon (Salmo salar) to water temperature (2·5–19·0 °C), was studied on the basis of temporal sequence of births and age at death of individual parasites on isolated salmon, and of infrapopulation growth on isolated and grouped salmon. Mean life-span of the parasite was negatively correlated with water temperature: 33·7 days at 2·5 °C and 4·5 days at 19·0 °C. The average number of offspring per parasite peaked between 6·5 and 13·0 °C, and was approximately 2·4 at these two temperatures. Both the period between the successive births of the offspring (max 4) and the estimated generation time were negatively correlated with temperature. The innate capacity for increase (rm) was positively correlated with temperature: from 0·02 (/parasite/day) at 2·5 °C to 0·22 (/parasite/day) at 19·0 °C. Growth of the infrapopulations was positively correlated with water temperature and was higher on isolated fish than on grouped fish, though less than the potential parasite population growth estimated from rm. In the infrapopulations the mean intensity of parasites continued to increase throughout all the experiments on both isolated fish and on grouped fish.

TEMPERATURE-DEPENDENT DEVELOPMENT OF EGGS AND LARVAE OF WINTHEMIA FUMIFERANAE TOTH. (DIPTERA: TACHINIDAE), A LARVAL–PUPAL PARASITOID OF THE SPRUCE BUDWORM (LEPIDOPTERA: TORTRICIDAE)

1990 ◽  
Vol 122 (2) ◽  
pp. 329-341 ◽  
Author(s):  
Christian Hébert ◽  
Conrad Cloutier
Keyword(s):  
Spruce Budworm ◽  
Development Rate ◽  
Temperature Dependent ◽  
Egg Development ◽  
Egg Hatching ◽  
Egg Deposition ◽  
Different Temperatures ◽  
Time Required ◽  
The Relationship ◽  
Eggs And Larvae

AbstractRelationships between temperature and development rates of eggs and larvae of Winthemia fumiferanae Toth. were experimentally determined, using the spruce budworm as host. Hatching of parasitoid eggs was triggered by host pupation. The median time required to complete egg development at different temperatures was estimated from distributions of percentage development success of the parasitoid over time between egg deposition and host pupation. For parasitoid eggs that had sufficient time to hatch, detachment from the host before pupation was the most important cause of mortality at 15 °C or higher, but was negligible below this temperature. A curvilinear model describing egg development rate as a function of temperature was used to simulate the development of W. fumiferanae eggs in the field. The relationship between larval development rate and temperature also was modelled, and the variability described. Simulations initiated by host pupation-driven egg hatching, and terminated with prepupal drop to the ground, are presented and discussed with respect to the appropriateness of using host pupation as an indicator of parasitoid egg hatching in the field.

scholarly journals Temperature-Dependent Broadening of the Ultraviolet Photoelectron Spectrum of Au(110)

Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5969
Author(s):  
Tomonari Nishida ◽  
Ikuo Kinoshita ◽  
Juntaro Ishii
Keyword(s):  
Fourier Transform ◽  
Temperature Dependence ◽  
Photoelectron Spectroscopy ◽  
Photoelectron Spectrum ◽  
Thermodynamic Temperature ◽  
Temperature Dependent ◽  
Photoelectron Emission ◽  
The Fourier Transform ◽  
The Relationship

To determine the thermodynamic temperature of a solid surface from the electron energy distribution measured by photoelectron spectroscopy, it is necessary to accurately evaluate the energy broadening of the photoelectron spectrum and investigate its temperature dependence. Broadening functions in the photoelectron spectrum of Au(110)’s surface near the Fermi level were estimated successfully using the relationship between the Fourier transform and the convolution integral. The Fourier transform could simultaneously reduce the noise of the spectrum when the broadening function was derived. The derived function was in the form of a Gaussian, whose width depended on the thermodynamic temperature of the sample and became broader at higher temperatures. The results contribute to improve accuracy of the determination of thermodynamic temperature from the photoelectron spectrum and provide useful information on the temperature dependence of electron scattering in photoelectron emission processes.

The Role of Calcium on the Release of Tissue Factor (Thromboplastie) Activity from Leukocytes

1975 ◽  
Author(s):  
T. W. Muhlfelder ◽  
I. Khan ◽  
J. Niemetz
Keyword(s):  
Tissue Factor ◽  
Maximum Activity ◽  
Release Mechanism ◽  
Temperature Dependent ◽  
Cell Contractility ◽  
Thromboplastic Activity ◽  
Significant Release ◽  
Ca Ions ◽  
The One

It is now well established that leukocytes may generate tissue factor (thromboplastic) activity (TFa), particularly after “stimulation” with endotoxin. As these leukocytes have also a thrombogenic effect, it appeared desirable to study the conditions in which the TFa was released. Leukocytes were obtained from the peritoneal cavity of rabbits after 2 doses of endotoxin and prepared as described previously (Nature New Biol. 232, 247, 1971). The leukocytes were incubated in siotonic buffered solutions, for up to 30 min then sedimented by centrifugation and the supemate removed for testing. The TFa was tested by the one stage test and the 2 stage assay. Significant release of procoagulant activity occured only when the leukocytes were suspended in solutions containing calcium. 2 mM of calcium caused maximum release of TFa while lower or higher concentrations were less effective. Other bivalent cations (Mg, Mn Zn) could not replace Ca ions and caused no release, while Co caused only very slight release of TFa. The release was time and temperature dependent: maximum activity being released at 37°C and almost no activity released at 4° C. When the effect of pH was studied, maximum release of TFa occurcd at pH 6.5–7.5. Substances which affect cell contractility such as vincristine, colchicine, cytochalasin B, as well as ouabain which affects some ATPase’s had no effect on release. These data show tlrat leukocyte tissue factor activity can be released from the cell in the presence of calcium. This release mechanism may play a role in some pathological conditions.(Supported in part by NIH Grant 13155 and VA 6060–01.)

The correspondence between sentence production and corpus frequencies in modifier attachment

2002 ◽  
Vol 55 (3) ◽  
pp. 879-896 ◽  
Author(s):  
Timothy Desmet ◽  
Marc Brysbaert ◽  
Constantijn De Baecke
Keyword(s):  
Noun Phrase ◽  
Relative Clause ◽  
Relative Clauses ◽  
Noun Phrases ◽  
Sentence Production ◽  
Syntactic Ambiguity ◽  
Attachment Preference ◽  
Attachment Sites ◽  
The Relationship ◽  
Relative Clause Attachment

We examined the production of relative clauses in sentences with a complex noun phrase containing two possible attachment sites for the relative clause (e.g., “Someone shot the servant of the actress who was on the balcony.”). On the basis of two corpus analyses and two sentence continuation tasks, we conclude that much research about this specific syntactic ambiguity has used complex noun phrases that are quite uncommon. These noun phrases involve the relationship between two humans and, at least in Dutch, induce a different attachment preference from noun phrases referring to non-human entities. We provide evidence that the use of this type of complex noun phrase may have distorted the conclusions about the processes underlying relative clause attachment. In addition, it is shown that, notwithstanding some notable differences between sentence production in the continuation task and in coherent text writing, there seems to be a remarkable correspondence between the attachment patterns obtained with both modes of production.

Permittivity Study of a CuCl Residue at 13–450 °C and Elucidation of the Microwave Intensification Mechanism for Its Dechlorination

2019 ◽  
Vol 38 (2019) ◽  
pp. 135-142
Author(s):  
Guo Zhanyong ◽  
Li Fachaung ◽  
Su Guang ◽  
Zhai Demei ◽  
Cheng Fang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Microwave Irradiation ◽  
Loss Factor ◽  
Elevated Temperatures ◽  
Temperature Dependent ◽  
Positive Interaction ◽  
Increasing Temperature ◽  
Relationship Of ◽  
The Relationship ◽  
Metallurgy Process

AbstractPermittivity is a vitally important parameter for describing the absorbing and heating characteristics of a material under microwave irradiation, and it is also strongly dependent on temperature. However, the literature contains little information on this topic and even less particular permittivity data at elevated temperatures. In this paper, the permittivity of a CuCl residue at temperatures from 13 to 450 °C at 2.45 GHz was measured using the cavity perturbation method. The relationship of its real part (ε′) and imaginary part (ε″) with temperature (T) was deduced. In addition, the temperature-dependent tangent (tan δ) and the penetration depth (d) of microwaves into the material were calculated. The results of the permittivity study show that the dielectric constant (ε′) of the CuCl residue increased linearly with increasing temperature. In contrast, the dielectric loss factor (ε″) and loss tangent first maintained on a steady value between 13 and 300 °C and then substantially increased from 300 to 450 °C. The positive interaction of the dielectric property and temperature showed the reasonableness of our earlier metallurgy process, where the CuCl residue for dechlorination was roasted at 350–450 °C under microwave irradiation.

Skeletal muscle fatigue in vitro is temperature dependent

1986 ◽  
Vol 61 (2) ◽  
pp. 660-665 ◽  
Author(s):  
S. S. Segal ◽  
J. A. Faulkner ◽  
T. P. White
Keyword(s):  
Effect Of Temperature ◽  
Isometric Contractions ◽  
Temperature Dependent ◽  
Temperature Optimum ◽  
Constant Frequency ◽  
Protocol Development ◽  
Effects Of Temperature ◽  
The Relationship ◽  
Bell Shaped Curve

Our purpose was to determine the effect of temperature on the fatigability of isolated soleus and extensor digitorum longus (EDL) muscles from rats during repeated isometric contractions. Muscles (70–90 mg) were studied at 20–40 degrees C in vitro. Fatigability was defined with respect to both the time and number of stimuli required to reach 50% of the force (P) developed at the onset of the fatigue test. Fatigue was studied during stimulation protocols of variable [force approximately 70% of maximum force (Po)] and constant frequency (28 Hz). Results for soleus and EDL muscles were qualitatively similar, but fatigue times were longer for soleus than for EDL muscles. During the variable-frequency protocol, development of approximately 70% of Po required an increase in stimulation frequency as temperature increased. During stimulation at these frequencies, fatigue time shortened as temperature increased. For both fatigue protocols, the relationship between temperature and the number of stimuli required to reach fatigue followed a bell-shaped curve, with maximum values at 25–30 degrees C. The temperature optimum for maximizing the number of isometric contractions to reach fatigue reflects direct effects of temperature on muscle function.

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