Rate Of Volume Increase Research Articles

Half‐graben basin filling models: new constraints on continental extensional basin development

AbstractThree end‐member models of half‐graben development (detachment fault, domino‐style, and fault growth) evolve differently through time and produce different basin‐filling patterns. The detachment fault model incorporates a basin‐bounding fault that soles into a subhorizontal detachment fault; the change in the rate of increase in the volume of the basin during uniform fault displacement is zero. Younger strata consistently pinch out against older synrift strata rather than pre‐rift rocks. Both basin‐bounding faults and the intervening fault blocks rotate during extension in the domino fault block model; a consequence of this rotation is that the change in the rate of increase of the volume of the basin is negative during uniform extension. Basin fill commonly forms a fanning wedge during fluvial sedimentation, whereas lacustrine strata tend to pinch out against older synrift strata. In the fault growth models, basins grow both wider and longer through time as the basin‐bounding faults lengthen and displacement accumulates; the change in the rate of increase in basin volume is positive. Fluvial strata progressively onlap pre‐rift rocks of the hanging wall block, whereas lacustrine strata pinch out against older fluvial strata at the centre of the basin but onlap pre‐rift rocks along the lateral edges. These fundamental differences may be useful in discriminating among the three end‐member models. The transition from fluvial to lacustrine deposition and hanging wall onlap relationships observed in numerous continental extensional basins are best explained by the fault growth models.

Infection of Pythium and Phytophthora species by Olpidiopsis gracilis (Oomycetes)

Zoospores from a culture of the biotrophic mycoparasite Olpidiopsis gracilis were inoculated on to vegetative hyphae of a range of Pythium and Phytophthora species. Twenty species of Pythium and two of Phytophthora were infected. The process of infection is described, and the optimum temperature for infection of Pythium sylvaticum was determined. Measurements of the expansion of infected portions of the hyphae of the Pythium host showed that despite the apparent hypertrophy, the rate of volume increase of the infected portions was not significantly different from that of uninfected hyphal apices.

Effects of a short period of drought on changes in tuber volume and specific leaf weight. I. Long-term changes

Single-stemmed potato plants, cv. Bintje, were grown on a nutrient solution under controlled conditions. They were exposed to a short drought stress, or remained untreated. Long-term measurements of tuber volume were carried out with a non-destructive volume-meter. Specific leaf weight was monitored with a β-gauge. Tubers from the same plant varied in rate and duration of growth. The relative growth of stressed tubers was 43–54% less than that of the control tubers. The hierarchy of tubers from one stem changed over time in plants that were exposed to the stress. Specific leaf weight declined during the stress period but there was a prompt recovery after the relief from drought. This response was similar to the response of the average rate of volume increase of the tuber.

Growth and Breakaway of Viscous Liquid Drops Hanging from a Tube

When a liquid drop hanging from the end of a vertical tube is increased in volume at a constant rate, the growth of the drop is divided into two stages. Until the volume of the drop reaches a certain critical value, the drop increases its vertical length in a stable manner. After that, the vertical length increases in an unstable manner, and is finally broken away. This experimental study is concerned with the effects of the increase rate of the drop volume and the viscosity of the drop substance upon the growth and the breakaway of the drop. The total volume of falling drops (a main drop and satellite drops) after breakaway increases with the increase rate of volume and the viscosity. Thus, the surface tension and the viscosity could be obtained by measuring the total volume of the falling drops for several increase rates of volume.

Diel changes in tuber volume

The long-term and short-term changes in volume of tubers from plants grown under controlled conditions, when assessed by an accurate, non-destructive tuber-volume meter, showed sigmoid increases in volume. The diel changes were remarkable: the rate of volume increase was very high shortly after the onset of the dark phase, but it declined sharply directly after the onset of the light phase; it was much faster during the night than during the day, especially in the later stages of growth. The nocturnal rate of volume increase was greatest when the tubers showed their greatest overall rate of growth. The daytime increases in volume were fastest during the early stages of tuber development. The key process underlying these phenomena seems to be the movement of water out of and into the tuber.

Ion transport by mitochondria-rich cells in toad skin.

The optical sectioning video imaging technique was used for measurements of the volume of mitochondria-rich (m.r.) cells of the isolated epithelium of toad skin. Under short-circuit conditions, cell volume decreased by about 14% in response to bilateral exposure to Cl-free (gluconate substitution) solutions, apical exposure to a sodium-free solution, or to amiloride. Serosal exposure to ouabain resulted in a large increase in volume, which could be prevented either by the simultaneous application of amiloride in the apical solution or by the exposure of the epithelium to bilateral Cl-free solutions. Unilateral exposure to a Cl-free solution did not prevent ouabain-induced cell swelling. It is concluded that m.r. cells have an amiloride-blockable Na conductance in the apical membrane, a ouabain-sensitive Na pump in the basolateral membrane, and a passive Cl permeability in both membranes. From the initial rate of ouabain-induced cell volume increase the active Na current carried by a single m.r. cell was estimated to be 9.9 +/- 1.3 pA. Voltage clamping of the preparation in the physiological range of potentials (0 to -100 mV, serosa grounded) resulted in a cell volume increase with a time course similar to that of the stimulation of the voltage-dependent Cl conductance. Volume increase and conductance activation were prevented by exposure of the tissue to a Cl-free apical solution. The steady-state volume of the m.r. cells increased with the clamping voltage, and at -100 mV the volume was about 1.15 times that under short-circuit conditions. The rate of volume increase during current passage was significantly decreased by lowering the serosal K concentration (Ki) to 0.5 mM, but was independent of whether Ki was 2.4, 5, or 10 mM. This indicates that the K conductance of the serosal membrane becomes rate limiting for the uptake of KCl when Ki is significantly lower than its physiological value. It is concluded that the voltage-activated Cl currents flow through the m.r. cells and that swelling is caused by an uptake of Cl ions from the apical bath and K ions from the serosal bath. Bilateral exposure of the tissue to hypo- or hypertonic bathing solutions changed cell volume without detectable changes in the Cl conductance. The volume response to external osmotic perturbations followed that of an osmometer with an osmotically inactive volume of 21%.(ABSTRACT TRUNCATED AT 400 WORDS)

Role of metabolism in effects of diflubenzuron on growth of B16 melanomas in mice.

The insect growth regulator diflubenzuron (DFB), which also inhibits growth of experimental tumors in mice, was studied to determine the influence of in vivo microsomal metabolism on its antitumor activity. DFB inhibits chitin synthesis and growth of imaginal epidermis in insects and suppresses melanogenesis and uptake of nucleosides in mouse melanoma cells, but the means of cell growth regulation and the role of metabolism of DFB in such regulation have not been established. Five daily injections of DFB (total of 4000 mg/kg) into C57BL/6 mice with B16 melanomas induced an acute 11-20% decrease in tumor volume and a 2-3 day increase in the initial tumor volume doubling time (Td), but at mid-treatment tumors regained maximum (control-like) rate of volume increase. Tumors in mice conditioned with a mixed function oxidase inhibitor (CoCl2) and treated with DFB did not decrease in mean volume, but their rate of volume increase was reduced by about 75% and the Td was increased by 4.2 days. In contrast, induction of mixed function oxidase with 3-methylcholanthrene (3-MC) or beta-napthaflavone (B-NF) enhanced the effects of DFB by a factor of 1.5 to 2.0. Therefore, aromatic hydroxylation of DFB may be required for tumor growth regulation. Three metabolites of DFB--two hydroxylated forms and a scission product, 4-chlorophenylurea (CPU), were also tested for tumor growth regulation. CPU was ineffective; a form oxidized at the 3 carbon of the phenyl ring (3-OH-DFB) was only marginally effective; but the 2-carbon form (2-OH-DFB) induced a 24% decrease in mean tumor volume and a 2.4 day increase in Td. Pretreatment with 3-MC and treatment with 2-OH-DFB also resulted in a 24% decrease in tumor volume and a 2.2 day increase in Td, but also reduced tumor volume increase to 20% between the 5th and 10th days after the initial 2-OH-DFB injection, compared to a 125% increase without 3-MC. Further, 3-MC pretreatment caused the otherwise marginally effective 3-OH-DFB to become almost as effective as 2-OH-DFB. These data support our previous report that DFB alters tumor growth and show that mixed function oxidase enhances effects of DFB, 2-OH-DFB and 3-OH-DFB.

Determination of thyroid volume using computerized ultrasonography and its clinical application

A new method for determining thyroid gland volume was developed by means of computerized ultrasonography. A maximum area of the thyroid (S) was obtained from coronal sections and a maximum thickness (C) was obtained from sagittal sections. The thyroid volume was then calculated by SXC. The volume of phantoms and pig thyroids obtained by this method was identical with the actual volume. The thyroid volume in this method correlated well with the estimated volume in patients with Graves' disease undergoing thyroidectomy (r = 0.954). The measurement was then performed in 56 healthy subjects (male 28, female 28, age 15-68 y.o.) and 126 patients with thyroid diseases. The thyroid volume in healthy men was significantly larger than that in women (18.4 +/- 6.1 ml vs 13.9 +/- 4.9 ml, Mean +/- SD, p less than 0.01). The thyroid volume in normal subjects correlated with body height, body weight or body surface area (p less than 0.01), which may explain the sex differences. An attempt was made to calculate the prospective thyroid volume (Y ml) from body height as follows; Y = 0.425 X - 52.8, X; body height (cm). Four out of thirty patients with untreated Graves' disease had a gland volume of the normal range, but in all patients the thyroid volume was larger than the prospective volume. The thyroid volume and the rate of volume increase (determined thyroid volume/calculated prospective volume) were correlated with the serum levels of T3, T4 concentration in the untreated stage. The volume and the rate of volume increase did not correlate with serum TSH receptor antibody activity. The thyroid volume in patients with Graves' disease who had been in remission (33.0 +/- 13.5 ml) was significantly smaller than that in untreated patients (51.8 +/- 24.4 ml, p less than 0.02). These findings indicate that the present method is reliable and clinically useful for the investigation of thyroid diseases.

Mixing Process of Arced Gas With Cold Gas in the Cylinder of Gas Circuit Breaker

Mixing process of high temperature and low temperature gases in the cylinder during arc back was observed for a model GCB with and without puffer action by shadow method. The volume and the temperature of the mixing region were estimated based on the results of the observation . The rate of volume increase of the mixed gas is expressed as a function of the arc power. The temperature of the mixed gas was found to decrease within ten milli-seconds after the arc initiation to around 300 K and 500 K in the cases with and without puffer action, respectively.

Effects of raised intraluminal pressure on gallbladder function and hepatic bile outflow in the cat.

Gallbladder concentrating function and motility and hepatic bile outflow were studied with a perfusion technique in anesthetized cats. The function of the gallbladder distended by an intraluminal pressure of 50 cm H2) was compared with its function at a pressure within the physiological range. It was found that gallbladder distention reduced the rate of net fluid absorption by 53% compared with controls. This reduction was abolished after intravenous administration of indomethacin, a prostaglandin synthetase inhibitor. At raised intraluminal pressure in the gallbladder a slow, continuous increase in the intraluminal capacity was seen. This rate of volume increase was markedly increased after indomethacin administration. A reduction of the hepatic bile outflow after indomethacin was seen in animals with distended gallbladder but not in controls. A mechanism by which gallbladder distention induces biosynthesis of prostaglandins in the gallbladder wall and thereby influences its function is suggested. The results are discussed in relation to clinical findings in man during acute cholecystitis, a situation in which the intraluminal pressure in the gallbladder usually is markedly elevated.

Development of the grape berry. I. Effects of time of flowering and competition

In an experiment on field-grown Vitis vinifera cv. Muscat Gordo Blanco, six times of flowering were established by using early and late developers amongst primary and secondary bunches on winter- and spring-pruned vines. Repeated measurements of the diameters of marked berries and of refraction (�Brix) of the juice of sampled berries were used to calculate berry volume and weight of solutes per berry. In a second experiment the effect of competition between bunches was tested by thinning. The volume-time curves were similar until 25 days after flowering, after which they diverged markedly. The chief reasons for divergence were the different rates and timing of deceleration during the first growth cycle, and the different lengths of the slow growth phase: berries from late flowers decelerated quickly but had a prolonged lag phase. Some, though not all, of these effects could be attributed to competition between bunches on the same vine. The inceptions of the solute accumulation phase and of the second growth cycle were coincident within treatments. The rates of increase in �Brix were uniform between treatments, despite large differences in berry volume increase. Solutes per berry increased linearly for 40 or more days, but at diverse rates that were influenced chiefly by the rate of volume increase in the second growth cycle. In some cases, solutes per berry continued to increase after berries had stopped growing. Temperature summations over the interval from flowering to 17�Brix were not constant.

THE PHOTOBIOLOGY OF FERN GAMETOPHYTES. II. THE PHOTOCONTROL OF FILAMENTOUS GROWTH AND ITS IMPLICATIONS FOR THE PHOTOCONTROL OF THE TRANSITION TO TWO‐DIMENSIONAL GROWTH

Current descriptions of the photocontrol of the filamentous growth of fern gametophytes contain several apparent photobiological anomalies. These anomalies are the result of the fundamental assumption that the rate of filament elongation is the growth parameter under direct photocontrol. This paper constructs and tests a model for the photocontrol of filamentous growth: k = A(dl/dt), where k, A, and (dl/dt) represent a constant rate of volume increase, the cross‐sectional area of the filament tip, and the rate of filament elongation, respectively. This model predicts that the photocontrol of filamentous growth could involve the direct regulation of the cross‐sectional area. Because this alternative perspective resolves the apparent photobiological anomalies, the photoresponse of the cross‐sectional area should represent the correct measure of the photocontrol over filamentous growth. It follows from the experimental results that the photocontrol of filamentous growth does not antagonize but rather preconditions the transition to two‐dimensional growth. Therefore, the original grounds for postulating that the transition in growth form involves the photoinduction of specific genes for two‐dimensional growth are no longer valid.

The Photobiology of Fern Gametophytes. II. The Photocontrol of Filamentous Growth and Its Implications for the Photocontrol of the Transition to Two-Dimensional Growth

Current descriptions of the photocontrol of the filamentous growth of fern gametophytes contain several apparent photobiological anomalies. These anomalies are the result of the fundamental assumption that the rate of filament elongation is the growth parameter under direct photocontrol. This paper constructs and tests a model for the photocontrol of filamentous growth: k = A(dl/dt), where k, A, and (dl/dt) represent a constant rate of volume increase, the cross-sectional area of the filament tip, and the rate of filament elongation, respectively. This model predicts that the photocontrol of filamentous growth could involve the direct regulation of the cross-sectional area. Because this alternative perspective resolves the apparent photobiological anomalies, the photoresponse of the cross-sectional area should represent the correct measure of the photocontrol over filamentous growth. It follows from the experimental results that the photocontrol of filamentous growth does not antagonize but rather preconditions the transition to two-dimensional growth. Therefore, the original grounds for postulating that the transition in growth form involves the photoinduction of specific genes for two-dimensional growth are no longer valid.

The Growth of Pure Bromide Monosize Emulsions

Monosized pure bromide emulsions were produced from seed crystals maintained in a supersaturated solution by double jetting at constant pAg. The addition rates necessary to maintain the supersaturation at a maximum without renucleation occurring were determined; this enabled experiments to be carried out at a fixed, though unknown, supersaturation. Under these conditions the effects of crystal number, crystal size and inter-crystal distance were examined.The narrowest size distribution was obtained when the supersaturation (i.e. addition rate) was at maximum. Under optimum conditions emulsion of cubic crystals could be produced with a standard deviation of less than 0.02 µ. on an edge of 1.0 µ.The maximum addition rate was such that the rate of increase in volume of the crystals was proportional to the surface area plus a small constant, i.e. the rate of increase of linear dimensions was nearly a constant. From this and the effects of inter-crystal distance it was concluded that growth rate was controIled mainly by polynucleation on the crystal surface and not by diffusion.

Control of cell growth in bacteria: experiments with thymine starvation.

When cells of Escherichia coli THU were starved for thymine, they continued to grow without division for at least two successive volume doublings at their initial rate. Within experimental error this average rate of volume increase, 0.21 mum(3) per hr, was identical with that observed in control cultures during two generations of growth in the presence of thymine. This growth rate was also independent of the age of the cells at the time of starvation. These results are consistent with the hypothesis, proposed earlier, that growth rates are controlled by uptake sites for binding, transport, or accumulation of compounds into the cell, that the number of these sites is constant throughout most of the cell cycle, and that this number doubles near or at cell division.

Control mechanisms determining rate and depth of respiratory movements

The relationship between ventilation ( E), tidal volume (V T) and frequency (f) was studied in cats under various conditions with and without intact vagus nerves. Ventilation was increased by a rebreathing technique and the respiratory pattern was altered i.a. by thermal and electrical stimulation. With intact vagi the E - V T relationship was similar to that of man (hey et al., 1966). After vagotomy the slope constant became smaller since, in this situation, only V T, but not f, increased with increasing chemical drive. The slope constant increased with increasing temperature from < 35°C and upwards due to a selective increase of f, whether the vagi were intact or cut. It is concluded that the increase in f in response to CO 2 is entirely dependent on the vagal mechanisms, while the bulbopontine pacemaker mechanisms act as the f-govemor when f is selectively increased e.g. by thermal stimulation and decortication. It was confirmed that the rate of increase of inspiratory activity depends on the chemical drive but is independent of the f-determining mechanisms. V T thus depends both on the rate of volume increase and on the part of the f-govemor which determines inspiratory duration.

Optical studies of the generation of noise in turbulent flames

A study of the mechanism of noise generation in turbulent premixed flames, turbulent diffusion flames and in liquid-spray combustion of hydrocarbon fuels is described. It is shown that all these flames may be represented acoustically as an assembly of monopole sound sources in their combustion zones. The radiated sound pressure is dependent upon the rate of change of the rate of increase of volume of the fuel and oxidant during combustion. The rate of volume increase is proportional to the rate of consumption of the fuel and oxidant in the flame. To measure this quantity, an optical technique has been employed that relies on observations of changes in the intensity of emission from the free radicals C 2 generated in the reaction zones of these flames. For the premixed flames, good quantitative agreement is obtained between the radiated sound pressure calculated from these intensity measurements, using simple acoustic theory, and the values recorded simultaneously with a microphone. Similar agreement is obtained for diffusion flames, with the assumption made that the fuel and oxidant burn in stoichiometric proportions. Qualitative agreement is obtained for the liquid-fuel flames. The mean intensities of emission from premixed flames, burning under varied conditions of turbulence, were found to depend linearly upon the total flow rate of the combustible mixture and to be independent of the conditions of turbulence. This observation is compatible with the wrinkled laminar flame model of turbulent flame propagation.

Sound emission from open turbulent premixed flames

A study of the noise produced by turbulent premixed flames stabilized on open burners is described. It is shown that such flames may be represented acoustically as a collection of monopole sound sources in the combustion zone. The radiated sound pressure is dependent on the rate of change of the rate of increase of volume of the gas during combustion, which varies owing to the turbulence in the flow. The rate of volume increase is proportional to the rate of consumption of combustible gas mixture in the flame. To measure this quantity, an optical technique has been developed which relies on observations of changes in the intensity of emission from the free radicals C 2 or CH generated in the reaction zone. Good quantitative agreement is obtained between the radiated sound pressures calculated from these intensity measurements and the values recorded simultaneously with a microphone. A correlation observed between the mean emission intensities of C 2 and CH radicals and the total flow rate of combustible gas mixture both in the laminar and turbulent flames, and in their transition region, supports the wrinkled laminar flame concept of turbulent flame propagation.

Flame noise: sound emission from spark-ignited bubbles of combustible gas

A study has been made of the noise produced by a flame developing in a spherical volume of homogeneous premixed combustible gas confined within a soap bubble and ignited by a spark. Such a spherically expanding flame was shown to act as a monopole source of sound, the pressure waveform being dependent on the rate of change of the rate of increase of volume of the gas during combustion. The rate of volume increase was proportional to the burning velocity of the combustible mixture multiplied by the flame area, and was estimated from optical measurements of flame movement which were made with a schlieren system and a rotating drum camera. Simultaneously the pressure in the sound wave emitted by the flame was recorded as a function of time. For a bubble ignited centrally, good quantitative agreement is obtained over a wide range of conditions between the measured pressure waveforms of the sound and those calculated from the optical records. The pressure amplitude in the sound wave increases markedly with burning velocity. It is shown that the sound pressure level in the radiated sound wave is substantially reduced by eccentric ignition compared with the centrally ignited case. The qualitative features of the pressure waveform obtained when a bubble is ignited eccentrically are adequately accounted for. It is further shown that the maximum fraction of energy of combustion that can be radiated as sound from a hydrocarbon-air flame of burning velocity 60 cm/s is of the order of 10 -6 .

Volume increase of kernels of corn and sorghum accompanying absorption of liquid water

AbstractThe linearity between weight and volume increases, which takes place when kernels of corn and sorghum are immersed in water, was established experimentally. The rate of volume increase was correlated according to an equation analogous to the diffusion equation. The coefficients of volume increase obeyed the Arrehenius equation. The results would be of practical value in designing steeping vessels, as well as of theoretical interest in elucidating the mechanism of water diffusion in cereal grains.