Static Pressure-Volume Curves for the Lung of the Frog (Rana Pipiens)

1978 ◽  
Vol 76 (1) ◽  
pp. 149-165 ◽  
Author(s):  
G. M. HUGHES ◽  
G. A. VERGARA
Keyword(s):  
Volume Change ◽  
Rana Pipiens ◽  
Static Pressure ◽  
Large Diameter ◽  
The Difference ◽  
Isolated Lungs ◽  
Precise Role ◽  
Different Parts

1. Static pressure/volume curves have been determined for isolated frog lungs inflated with either air or saline. In both cases a hysteresis was present: the pressure required to produce unit change of volume being greater during inflation than deflation. 2. The pressure necessary for a given volume change was less for the saline-filled than the air-filled lungs. The difference between these curves is due to the surface tension at the air/lung interface. 3. Pressure/volume curves for air-filled lungs in situ were similar to curves for isolated lungs. However, a greater pressure was required for the same volume change during both inflation and deflation. 4. Compliance was calculated from different parts of air pressure/volume curves and gave values greater than those obtained using similar calculations for higher vertebrates. 5. These observations support other evidence for the presence of a surfactant in the lung lining of frogs in spite of the relatively large diameter of their ‘alveoli.’ The precise role of such a lining is uncertain and it is concluded that similar forces may be involved during the inflation and deflation of lungs of frogs and higher vertebrates in spite of differences in gross morphology.

Phosphagen and intracellular pH changes during contraction of creatine-depleted rat muscle

1986 ◽  
Vol 250 (2) ◽  
pp. C264-C274 ◽  
Author(s):  
R. A. Meyer ◽  
T. R. Brown ◽  
B. L. Krilowicz ◽  
M. J. Kushmerick
Keyword(s):  
Steady State ◽  
Intracellular Ph ◽  
Muscle Metabolism ◽  
Surface Coil ◽  
The Difference ◽  
Transfer Method ◽  
Fast Twitch ◽  
Resting Muscle

To evaluate the functional role of phosphocreatine (PCr) and creatine in muscle metabolism, these compounds were depleted by feeding rats the creatine analogue, beta-guanidinopropionate (beta-GPA, 2% of diet). Changes in phosphate metabolites and intracellular pH were monitored in gastrocnemius muscle in situ by phosphorus nuclear magnetic resonance (31P-NMR) at 162 MHz using the surface coil technique. After 3 mo of feeding, 25 mumol/g of phosphorylated beta-GPA (beta-GPAP) had accumulated, and PCr, creatine, and ATP levels were reduced to 6, 17, and 56%, respectively, compared with muscles of control animals. In resting muscle, there was no measurable exchange of phosphate between beta-GPAP and ATP by the NMR saturation transfer method. During muscle stimulation at 1 and 5 Hz, the maximum net rate of beta-GPAP hydrolysis was 10% that of PCr in control muscles, so that after 150 s inorganic phosphate had increased to less than 50% of the level attained in control muscles. At both rates, peak twitch force declined toward a steady state more rapidly in beta-GPA-loaded muscles, but after 100 s force was either not different (1 Hz) or significantly greater (5 Hz) in the beta-GPA-fed animals. Intracellular pH initially decreased more rapidly during stimulation and recovered more rapidly afterward in the beta-GPA-loaded muscles compared with controls. This difference could be explained by the difference in expected proton consumption due to net PCr hydrolysis. However, despite buffering by PCr hydrolysis, pH ultimately decreased more in control muscle (6.1 vs. 6.3 for 5 Hz), indicating greater acid accumulation compared with beta-GPA-loaded muscles. In the superficial, predominantly fast-twitch glycolytic section of muscles clamp-frozen after 5-Hz stimulation for 150 s, lactate accumulation was twofold greater in controls. The results indicate that PCr is not essential for steady-state energy production but that the phosphate from PCr hydrolysis may be important for maximum activation of glycogenolysis and/or glycolysis.

On the role of phonology and discourse in Francilian Frenchwh-questions

2010 ◽  
Vol 47 (1) ◽  
pp. 129-162 ◽  
Author(s):  
FATIMA HAMLAOUI
Keyword(s):  
Recent Work ◽  
Metropolitan Area ◽  
Theoretic Analysis ◽  
Discourse Context ◽  
The Difference ◽  
The Right ◽  
Sentence Stress

It is argued that in Francilian French, the dialect of French spoken in the Paris metropolitan area, in-situ and frontedwh-questions have the same answerhood conditions but vary with respect to their respective focus-set (Reinhart 2006). The difference between the two types of questions lies in the discourse status of their non-whportion. Whereas thewh-phrase is never discourse-given, the non-whportion may or may not be, depending on the discourse context. In Francilian French in-situwh-questions, the non-whportion must be discourse-given. As this language exhibits a strong requirement on sentence stress to be kept rightmost it cannot, in contrast with English, assign sentence stress to a frontedwh-phrase when the non-whportion is discourse-given and needs to be destressed. The only way to simultaneously destress discourse-given items and keep sentence stress rightmost is by aligning thewh-phrase with the right edge of the clause. Whereas in Hungarian prosody triggers movement (Szendrői 2003), in Francilian French, prosody prevents it from occurring. An Optimal Theoretic analysis in the spirit of much recent work on focus and givenness in declaratives (Samek-Lodovici 2005, Féry & Samek-Lodovici 2006) captures this phenomenon.

scholarly journals Pipes to Earth's subsurface: The role of atmospheric conditions in controlling air transport through boreholes and shafts

2018 ◽  
Author(s):  
Elad Levintal ◽  
Nadav G. Lensky ◽  
Amit Mushkin ◽  
Noam Weisbrod
Keyword(s):  
Large Diameter ◽  
Absolute Humidity ◽  
Barometric Pressure ◽  
Atmospheric Temperature ◽  
Air Transport ◽  
Atmospheric Conditions ◽  
Air Masses ◽  
Diurnal Cycles

Abstract. Understanding air exchange dynamics between underground cavities (e.g., caves, mines, boreholes, etc.) and the atmosphere is significant for the exploration of gas transport across the Earth-atmosphere interface. Here, we investigated the role of atmospheric conditions in air transport inside boreholes through in-situ observations. Three geometries were explored: (1) a narrow and deep shaft (0.1 m and 27 m, respectively), ending in a large underground cavity; (2) the same shaft after the pipe was lowered and separated from the cavity; and (3) a deep large-diameter borehole (3.4 m and 59 m, respectively). Absolute humidity was found to be a reliable proxy for distinguishing between atmospheric and cavity air masses and thus to explore air transport through the three geometries. Airflow directions in the first two narrow-diameter geometries were found to be driven by changes in barometric pressure whereas airflow in the large-diameter geometry was correlated primarily to the diurnal cycles of ambient atmospheric temperature. High CO2 concentrations (~ 2000 ppm) were found in all three geometries, which can indicate that the airflow to the atmosphere is also significant to the investigation of greenhouse gas emissions.

G-protein Golfalpha (GNAL) is expressed in the vestibular end organs and primary afferent neurons of Rattus norvegicus

2005 ◽  
Vol 15 (1) ◽  
pp. 11-15
Author(s):  
P. Ashley Wackym ◽  
Joseph A. Cioffi ◽  
Christy B. Erbe ◽  
Paul Popper
Keyword(s):  
G Protein ◽  
Membrane Bound ◽  
Polymerase Chain ◽  
G Protein Alpha Subunit ◽  
Guanine Nucleotide Binding ◽  
Nucleotide Binding Proteins ◽  
Guanine Nucleotide Binding Proteins ◽  
Precise Role

Guanine nucleotide binding proteins (G-proteins) play an important role in mediating signals transduced across the cell membrane by membrane-bound receptors. The precise role of these proteins and their coupled receptors in the physiology of the vestibular neuroepithelium is poorly understood. Although Golfalpha was originally discovered in the olfactory neuroepithelium and striatum, we recently identified this G-protein alpha subunit in a normalized cDNA library constructed from rat vestibular end organs and vestibular nerves including Scarpa's ganglia. In order to further characterize Golfalpha in the rat vestibular periphery, we used in situ hybridization and reverse transcription polymerase chain reaction to determine the anatomic context of this gene expression. Golfalpha was found in both the end organs and the ganglia and could serve unique roles in the physiology of the vestibular neuroepithelium.

scholarly journals The Role of Reduced Graphene Oxide in the Suspension Polymerization of Styrene and Its Effect on the Morphology and Thermal Properties of the Polystyrene/rGO Nanocomposites

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1468
Author(s):  
Marta Sieradzka ◽  
Janusz Fabia ◽  
Dorota Biniaś ◽  
Ryszard Fryczkowski ◽  
Jarosław Janicki
Keyword(s):  
Graphene Oxide ◽  
Thermal Properties ◽  
Reduced Graphene Oxide ◽  
Suspension Polymerization ◽  
Decomposition Temperature ◽  
Reduced Graphene ◽  
The Difference ◽  
Polar Functional Groups

Reduced graphene oxide (rGO) was used to obtain Polystyrene (PS)/rGO nanocomposites via in-situ suspension polymerization. The main goal of the article was to determine how rGO influences the morphology and thermal properties of PS beads. The obtained samples were studied by means of a scanning electron microscope (SEM), and calorimetric and thermogravimetric analysis (DCS, TGA). It was proven that the addition of rGO, due to the presence of polar functional groups, causes significant changes in bead sizes and size distribution, and in their morphology (on the surface and in cross-section). The increasing amount of rGO in the polymer matrix increased the size of beads from 0.36 to 3.17 mm for pure PS and PS with 0.2 wt% rGO content, respectively. PS/rGO nanocomposites are characterized by distinctly improved thermostability, which is primarily expressed in the increase in their decomposition temperature. For a sample containing 0.3 wt% rGO, the difference is more than 12 °C in comparison to pure PS beads.

The role of differential phase contrast in electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 176-177
Author(s):  
E.M. Waddell ◽  
J.N. Chapman ◽  
R.P. Ferrier
Keyword(s):  
Phase Contrast ◽  
Practical Method ◽  
Position Vector ◽  
Differential Phase ◽  
Pure Phase ◽  
Differential Phase Contrast ◽  
The Difference ◽  
Image Position ◽  
First Moment

Dekkers and de Lang (1977) have discussed a practical method of realising differential phase contrast in a STEM. The method involves taking the difference signal from two semi-circular detectors placed symmetrically about the optic axis and subtending the same angle (2α) at the specimen as that of the cone of illumination. Such a system, or an obvious generalisation of it, namely a quadrant detector, has the characteristic of responding to the gradient of the phase of the specimen transmittance. In this paper we shall compare the performance of this type of system with that of a first moment detector (Waddell et al.1977).For a first moment detector the response function R(k) is of the form R(k) = ck where c is a constant, k is a position vector in the detector plane and the vector nature of R(k)indicates that two signals are produced. This type of system would produce an image signal given bywhere the specimen transmittance is given by a (r) exp (iϕ (r), r is a position vector in object space, ro the position of the probe, ⊛ represents a convolution integral and it has been assumed that we have a coherent probe, with a complex disturbance of the form b(r-ro) exp (iζ (r-ro)). Thus the image signal for a pure phase object imaged in a STEM using a first moment detector is b2 ⊛ ▽ø. Note that this puts no restrictions on the magnitude of the variation of the phase function, but does assume an infinite detector.

On the Role of Transferrin in 67Ga Uptake by Tumor Cells

1988 ◽  
Vol 27 (04) ◽  
pp. 151-153
Author(s):  
P. Thouvenot ◽  
F. Brunotte ◽  
J. Robert ◽  
L. J. Anghileri
Keyword(s):  
Specific Binding ◽  
Subcellular Fractionation ◽  
Animal Blood ◽  
Tumor Bearing ◽  
Cell Structures ◽  
The Difference ◽  
Sarcoma Cells ◽  
In Vitro Uptake

In vitro uptake of 67Ga-citrate and 59Fe-citrate by DS sarcoma cells in the presence of tumor-bearing animal blood plasma showed a dramatic inhibition of both 67Ga and 59Fe uptakes: about ii/io of 67Ga and 1/5o of the 59Fe are taken up by the cells. Subcellular fractionation appears to indicate no specific binding to cell structures, and the difference of binding seems to be related to the transferrin chelation and transmembrane transport differences

REFLECTION COEFFICIENT OF AN ELECTROMAGNETIC WAVE IN CONDUCTIVE MEDIA

2018 ◽  
pp. 100-106
Author(s):  
M. S. Sudakova ◽  
M. L. Vladov ◽  
M. R. Sadurtdinov
Keyword(s):  
Reflection Coefficient ◽  
Ground Penetrating Radar ◽  
Electromagnetic Waves ◽  
Water Contamination ◽  
Survey Design ◽  
Direct And Inverse Problems ◽  
The Difference ◽  
Ground Penetrating ◽  
Ideal Dielectric

Within the ground penetrating radar bandwidth the medium is considered to be an ideal dielectric, which is not always true. Electromagnetic waves reflection coefficient conductivity dependence showed a significant role of the difference in conductivity in reflection strength. It was confirmed by physical modeling. Conductivity of geological media should be taken into account when solving direct and inverse problems, survey design planning, etc. Ground penetrating radar can be used to solve the problem of mapping of halocline or determine water contamination.

Speculative Realism and Science Fiction

2017 ◽  
Author(s):  
Brian Willems
Keyword(s):  
Science Fiction ◽  
Identity Formation ◽  
Cormac Mccarthy ◽  
Doris Lessing ◽  
Speculative Realism ◽  
Neil Gaiman ◽  
The World ◽  
The Difference ◽  
Quentin Meillassoux

A human-centred approach to the environment is leading to ecological collapse. One of the ways that speculative realism challenges anthropomorphism is by taking non-human things to be as valid objects of investivation as humans, allowing a more responsible and truthful view of the world to take place. Brian Willems uses a range of science fiction literature that questions anthropomorphism both to develop and challenge this philosophical position. He looks at how nonsense and sense exist together in science fiction, the way in which language is not a guarantee of personhood, the role of vision in relation to identity formation, the difference between metamorphosis and modulation, representations of non-human deaths and the function of plasticity within the Anthropocene. Willems considers the works of Cormac McCarthy, Paolo Bacigalupi, Neil Gaiman, China Miéville, Doris Lessing and Kim Stanley Robinson are considered alongside some of the main figures of speculative materialism including Graham Harman, Quentin Meillassoux and Jane Bennett.

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