Journal articles: 'Vibro fluctuations'

1

Dong, Liang, Yuemin Zhao, Liping Peng, et al. "Characteristics of pressure fluctuations and fine coal preparation in gas-vibro fluidized bed." Particuology 21 (August 2015): 146–53. http://dx.doi.org/10.1016/j.partic.2014.08.011.

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Bajic´, Branko, and Andreas Keller. "Spectrum Normalization Method in Vibro-Acoustical Diagnostic Measurements of Hydroturbine Cavitation." Journal of Fluids Engineering 118, no. 4 (1996): 756–61. http://dx.doi.org/10.1115/1.2835506.

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Full-scale vibro-acoustical diagnostic measurements of cavitation in four Francis 6 MW double runner turbines were performed. Two types of sensors were used—a hydrophone sensing waterborne noise at the pressure side of a runner and an accelerometer mounted at various points at the outer turbine casing, facing the runner’s pressure side. The correlation of noise and acceleration intensity with suction-side pressure fluctuations and runner position was checked. A simple but efficient method of spectrum normalization, which rejects the influence of the measurement set characteristics and vibro-acoustical characteristics of a turbine, was developed. The resulting spectra reveal the dependence of cavitation source strength on the turbine power as a function of noise or acceleration frequency.

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Kadmiri, Y., J. Perret-Liaudet, E. Rigaud, A. Le Bot, and L. Vary. "Influence of Multiharmonics Excitation on Rattle Noise in Automotive Gearboxes." Advances in Acoustics and Vibration 2011 (September 5, 2011): 1–6. http://dx.doi.org/10.1155/2011/659797.

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We consider the automotive gearbox rattle noise resulting from vibro-impacts that can occur between the idle gears under excessive velocity fluctuations of the shaft-driving gears imposed by engine torque fluctuation. Even if the rattling phenomenon has no consequence on reliability, it may be particularly annoying for vehicle interior sound quality and acoustic comfort. The main parameters governing such kind of vibrations are the excitation source associated with engine torque fluctuation which can be modeled by an imposed displacement of the driveline, the inertia of the idle gear, the drag torque acting during the free flight motion, and the impact laws. In the case of rattle, it is reasonable to assume that duration of impacts between teeth is very short compared to the excitation period. Then, these impacts are modeled by a coefficient of restitution law. The excitation source is not composed only with fundamental component but also with other harmonic components. This study presents some effects of these additional components on the dynamic response of the idle gear.

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Brancati, Renato, Ernesto Rocca, Daniela Siano, and Massimo Viscardi. "Experimental vibro-acoustic analysis of the gear rattle induced by multi-harmonic excitation." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 232, no. 6 (2017): 785–96. http://dx.doi.org/10.1177/0954407017707670.

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The paper reports a wide vibro-acoustic experimental investigation of the gear rattle phenomenon induced by multi-harmonic excitation. The analysis is performed by using different measurement techniques which allow some of the significant parameters in this type of investigation to be acquired on a specific test rig: the angular rotations of the gears by using encoders; the accelerations obtained from a triaxial accelerometer; the sound pressure level determined by employing both acoustic microphones; the correct evaluation of the acoustic sources by utilizing a p–v sound intensity probe. Performance indices were adopted to compare the dynamic behaviours of the system with respect to some parameters, such as the speed of the pinion, the fluctuations in the speed of the pinion and the lubrication conditions. The results of the comparative analysis show very good agreement between the vibro-acoustic measurements and the results from the encoder-based method; this has helped us to interpret the physical behaviour of the gear pair with respect to the impacts occurring between the teeth during the different phases of the phenomenon. Moreover, the study indicates interesting aspects of the effects of multi-harmonic excitation on the rattle phenomenon, with particular attention to the influence of lubrication on the reduction in the rattle noise.

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Mironova, N. A. "Research of the heat of physical characteristics of fruit ossicles." Power engineering: research, equipment, technology 21, no. 6 (2020): 19–28. http://dx.doi.org/10.30724/1998-9903-2019-21-6-19-28.

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Utilization of fruit seeds plays a special role, since they are a valuable raw material for the oil and fat industry, at the enterprises of which the complex processing of seeds is carried out: oil is obtained from kernels, crumbs and powder are obtained from shells. Before placing the seeds in the oil and fat enterprises, they must be cleaned of impurities and dried, since the seeds extracted from the fruits have an increased humidity of 25-60% and contain a significant amount of impurities in the form of pulp and squeezes. However, due to the lack of specialized equipment for drying fruit seeds in canneries, their supply to the kernel oil plants is declining every year. In this case, tons of seeds are simply destroyed. Attempts to use existing industrial dryers proved to be ineffective, since they do not take into account the structural features of fruit seeds, and are also not very adapted to significant fluctuations in the moisture of raw seeds and the unevenness of their receipt on drying. The most appropriate method of drying fruit seeds is the use of infrared radiation and a vibro-boiling layer.

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Wang, Jing-Shang, Ye Huang, Shuping Zhang та ін. "A Protective Role of Paeoniflorin in Fluctuant Hyperglycemia-Induced Vascular Endothelial Injuries through Antioxidative and Anti-Inflammatory Effects and Reduction of PKCβ1". Oxidative Medicine and Cellular Longevity 2019 (10 квітня 2019): 1–11. http://dx.doi.org/10.1155/2019/5647219.

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Hyperglycemia fluctuation is associated with diabetes mellitus (DM) complications when compared to persistent hyperglycemia. Previous studies have shown that paeoniflorin (PF), through its antiapoptosis, anti-inflammation, and antithrombotic properties, effectively protects against cardiovascular and cerebrovascular disease. However, the mechanism underlying the protection from PF against vascular injuries induced by hyperglycemia fluctuations remains poorly understood. Herein, we investigated the potential protective role of PF on human umbilical vein endothelial cells (HUVECs) subjected to intermittent glucose levels in vitro and in DM rats with fluctuating hyperglycemia in vivo. A remarkable increased apoptosis associated with elevated inflammation, increased oxidative stress, and high protein level of PKCβ1 was induced in HUVECs by intermittently changing glucose for 8 days, and PF recovered those detrimental changes. LY333531, a potent PKCβ1 inhibitor, and metformin manifested similar effects. Additionally, in DM rats with fluctuating hyperglycemia, PF protected against vascular damage as what has been observed in vitro. Taken together, PF attenuates the vascular injury induced by fluctuant hyperglycemia through oxidative stress inhibition, inflammatory reaction reduction, and PKCβ1 protein level repression, suggesting its perspective clinical usage.

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Niccolini Marmont Du Haut Champ, Carlo Alberto, Aristide Fausto Massardo, Mario Luigi Ferrari, and Paolo Silvestri. "Surge prevention in gas turbines: an overview over historical solutions and perspectives about the future." E3S Web of Conferences 113 (2019): 02003. http://dx.doi.org/10.1051/e3sconf/201911302003.

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The aim of the present work is to retrace experimental, analytical and numerical analyses which deal with compressor instability phenomena, such as rotating stall and surge. While the first affects only the machine itself, the second involves the whole energy system. Surge onset is characterized by strong pressure and mass flow rate fluctuations which can even lead to reverse flow through the compressor. Experimental studies on prevention of axial compressor fluid dynamic instabilities, which can be propagated and eventually damage the solid structure, have been carried out by many authors. The first important studies on this topic tried to underline the main aspects of the complex detailed mechanism of surge, by replacing the compression system with an equivalent conceptual lumped parameter model. This is specially meant to capture the unsteady behaviour and the transient response of the compression system itself, particularly its dependence on variations in the volume of discharge downstream and in the settings of the throttle valve at its outlet (which simulates the actual load coupled to the compressor). Greitzer’s model is still regarded as the milestone for new investigations about active control and stabilization of surge and, more generally, about active suppression of aerodynamic instabilities in turbomachinery. During the last years, a lot of simulations and experimental studies about surge have been conducted on multistage centrifugal compressors with different architectures (e.g. equipped with vaneless or vaned diffusers). Moreover, further kinds of analysis try to extend the stable working zone of compressors, identifying stall and surge precursors extractable from information contained in the vibro-acoustical and rotodynamic response of the system.

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Kreeger, Lauren J., Arslaan Arshed, and Katrina M. MacLeod. "Intrinsic firing properties in the avian auditory brain stem allow both integration and encoding of temporally modulated noisy inputs in vitro." Journal of Neurophysiology 108, no. 10 (2012): 2794–809. http://dx.doi.org/10.1152/jn.00092.2012.

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The intrinsic properties of tonically firing neurons in the cochlear nucleus contribute to representing average sound intensity by favoring synaptic integration across auditory nerve inputs, reducing phase locking to fine temporal acoustic structure and enhancing envelope locking. To determine whether tonically firing neurons of the avian cochlear nucleus angularis (NA) resemble ideal integrators, we investigated their firing responses to noisy current injections during whole cell patch-clamp recordings in brain slices. One subclass of neurons (36% of tonically firing neurons, mainly subtype tonic III) showed no significant changes in firing rate with noise fluctuations, acting like pure integrators. In contrast, many tonically firing neurons (>60%, mainly subtype tonic I or II) showed a robust sensitivity to noisy current fluctuations, increasing their firing rates with increased fluctuation amplitudes. For noise-sensitive tonic neurons, the firing rate vs. average current curves with noise had larger maximal firing rates, lower gains, and wider dynamic ranges compared with FI curves for current steps without noise. All NA neurons showed fluctuation-driven patterning of spikes with a high degree of temporal reliability and millisecond spike time precision. Single-spiking neurons in NA also responded to noisy currents with higher firing rates and reliable spike trains, although less precisely than nucleus magnocellularis neurons. Thus some NA neurons function as integrators by encoding average input levels over wide dynamic ranges regardless of current fluctuations, others detect the degree of coherence in the inputs, and most encode the temporal patterns contained in their inputs with a high degree of precision.

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Demb, Jonathan B., Peter Sterling, and Michael A. Freed. "How Retinal Ganglion Cells Prevent Synaptic Noise From Reaching the Spike Output." Journal of Neurophysiology 92, no. 4 (2004): 2510–19. http://dx.doi.org/10.1152/jn.00108.2004.

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Synaptic vesicles are released stochastically, and therefore stimuli that increase a neuron's synaptic input might increase noise at its spike output. Indeed this appears true for neurons in primary visual cortex, where spike output variability increases with stimulus contrast. But in retinal ganglion cells, although intracellular recordings (with spikes blocked) showed that stronger stimuli increase membrane fluctuations, extracellular recordings showed that noise at the spike output is constant. Here we show that these seemingly paradoxical findings occur in the same cell and explain why. We made intracellular recordings from ganglion cells, in vitro, and presented periodic stimuli of various contrasts. For each stimulus cycle, we measured the response at the stimulus frequency (F1) for both membrane potential and spikes as well as the spike rate. The membrane and spike F1 response increased with contrast, but noise (SD) in the F1 responses and the spike rate was constant. We also measured membrane fluctuations (with spikes blocked) during the response depolarization and found that they did increase with contrast. However, increases in fluctuation amplitude were small relative to the depolarization (<10% at high contrast). A model based on estimated synaptic convergence, release rates, and membrane properties accounted for the relative magnitudes of fluctuations and depolarization. Furthermore, a cell's peak spike response preceded the peak depolarization, and therefore fluctuation amplitude peaked as the spike response declined. We conclude that two extremely general properties of a neuron, synaptic convergence and spike generation, combine to minimize the effects of membrane fluctuations on spiking.

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Hayashi, Kumiko, Yuta Tsuchizawa, Mitsuhiro Iwaki, and Yasushi Okada. "Application of the fluctuation theorem for noninvasive force measurement in living neuronal axons." Molecular Biology of the Cell 29, no. 25 (2018): 3017–25. http://dx.doi.org/10.1091/mbc.e18-01-0022.

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Although its importance is recently widely accepted, force measurement has been difficult in living biological systems, mainly due to the lack of the versatile noninvasive force measurement methods. The fluctuation theorem, which represents the thermodynamic properties of small fluctuating nonequilibrium systems, has been applied to the analysis of the thermodynamic properties of motor proteins in vitro. Here we extend it to the axonal transport (displacement) of endosomes. The distribution of the displacement fluctuation had three or four distinct peaks around multiples of a unit value, which the fluctuation theorem can convert into the drag force exerted on the endosomes. The results demonstrated that a single cargo vesicle is conveyed by one to three or four units of force production.

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Yokobori, A. T., T. Maeyama, T. Ohkuma, et al. "Bio-Medico-Mechanical Behavior of Natural Artery Blood Vessel Under Constant and Variable Internal Pulsatile Pressure Flow Test In Vitro." Journal of Biomechanical Engineering 108, no. 4 (1986): 295–300. http://dx.doi.org/10.1115/1.3138617.

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Studies have been carried out on the bio-medico-mechanical behavior in vitro of natural blood vessel (dogs) under constant and variable internal pulsatile pressure flow. The apparatus designed by us well simulated the arterial system. The studies were made for the case of pressure amplitude kept as constant, of the two-step-multi-duplicated pulsatile pressure and of the fluctuating pressure. For the case of the fluctuating pressure, the strength of the artery becomes considerably lower than those under constant amplitude and two-step-multi-duplicated pulsatile pressure. SEM observations of the inner walls of the artery shows that collagen fibers are more elongated under fluctuating pulsatile pressure flow. In conclusion, in order to avoid the mechanical deterioration of the artery strength, it is useful to keep the pulsatile blood pressure at constant amplitude. Even for the case of the blood pressure fluctuation, it is necessary to manage to keep the blood pressure as near a regular wave as possible, the total number of repeated pulse being equal.

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IWABUCHI, Masatoshi, Yuusuke NAOI, Hideyasu SUMIYA, and Masatake SHIRAISHI. "302 Vibro Masseur Relaxation Device using Fluctuation Eect." Proceedings of Ibaraki District Conference 2008 (2008): 61–62. http://dx.doi.org/10.1299/jsmeibaraki.2008.61.

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Ishijima, Akihiko, Takashi Doi, Katsuhiko Sakurada, and Toshio Yanagida. "Sub-piconewton force fluctuations of actomyosin in vitro." Nature 352, no. 6333 (1991): 301–6. http://dx.doi.org/10.1038/352301a0.

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14

Schmedt, E., and L. Kleiman. "The measurement of the production of during erythroid differentiation of the Friend erythroleukemia cell." Biochemistry and Cell Biology 65, no. 3 (1987): 188–94. http://dx.doi.org/10.1139/o87-024.

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The production of [Formula: see text] during Friend cell erythroid differentiation has been studied. In vitro measurements of total nuclear RNA synthesis in nuclei isolated from Friend cells at different stages of differentiation show the total RNA synthesis increases 1.5-fold at day 1 of induction and then decreases through days 2 and 3 to approximately 75% of its rate of synthesis in the nuclei of uninduced cells. The synthesis of RNA polymerase III transcripts undergoes a similar fluctuation through day 2 of induction, but increases again at day 3. The specific synthesis of [Formula: see text] was measured by hybridization of labelled nuclear RNA to a [Formula: see text] gene probe. During erythroid differentiation the percentage of nuclear RNA represented by [Formula: see text] remains constant (0.065%), so that the absolute synthesis of [Formula: see text] fluctuates during differentiation, in parallel with the fluctuations in the synthesis of total nuclear RNA. The relative synthesis of [Formula: see text]in vivo was studied by labelling cells with 35Pi, isolating the resulting radioactive tRNA – 5S RNA population, and hybridizing this population to a [Formula: see text] gene probe. The ratio of [Formula: see text] in newly synthesized cytoplasmic RNA remains similar throughout differentiation (averaging 0.0171), implying that the fluctuations observed in the nuclear synthesis of [Formula: see text] during differentiation probably also occur for the nuclear synthesis of most tRNA and 5S RNA species. Attempts were made to measure the relative steady-state concentration of [Formula: see text] using both aminoacylation and in vitro end labelling of tRNA followed by hybridization to a [Formula: see text] gene probe. These two methods gave different results and we discuss the possible pitfalls of using enzymatic methods for quantitating tRNA concentrations in the cell.

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Townsley, Loni, Marilou P. Sison Mangus, Sanjin Mehic, and Fitnat H. Yildiz. "Response of Vibrio cholerae to Low-Temperature Shifts: CspV Regulation of Type VI Secretion, Biofilm Formation, and Association with Zooplankton." Applied and Environmental Microbiology 82, no. 14 (2016): 4441–52. http://dx.doi.org/10.1128/aem.00807-16.

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ABSTRACTThe ability to sense and adapt to temperature fluctuation is critical to the aquatic survival, transmission, and infectivity ofVibrio cholerae, the causative agent of the disease cholera. Little information is available on the physiological changes that occur whenV. choleraeexperiences temperature shifts. The genome-wide transcriptional profile ofV. choleraeupon a shift in human body temperature (37°C) to lower temperatures, 15°C and 25°C, which mimic those found in the aquatic environment, was determined. Differentially expressed genes included those involved in the cold shock response, biofilm formation, type VI secretion, and virulence. Analysis of a mutant lacking the cold shock genecspV, which was upregulated >50-fold upon a low-temperature shift, revealed that it regulates genes involved in biofilm formation and type VI secretion. CspV controls biofilm formation through modulation of the second messenger cyclic diguanylate and regulates type VI-mediated interspecies killing in a temperature-dependent manner. Furthermore, a strain lackingcspVhad significant defects for attachment and type VI-mediated killing on the surface of the aquatic crustaceanDaphnia magna. Collectively, these studies reveal thatcspVis a major regulator of the temperature downshift response and plays an important role in controlling cellular processes crucial to the infectious cycle ofV. cholerae.IMPORTANCELittle is known about how human pathogens respond and adapt to ever-changing parameters of natural habitats outside the human host and how environmental adaptation alters dissemination.Vibrio cholerae, the causative agent of the severe diarrheal disease cholera, experiences fluctuations in temperature in its natural aquatic habitats and during the infection process. Furthermore, temperature is a critical environmental signal governing the occurrence ofV. choleraeand cholera outbreaks. In this study, we showed thatV. choleraereprograms its transcriptome in response to fluctuations in temperature, which results in changes to biofilm formation and type VI secretion system activation. These processes in turn impact environmental survival and the virulence potential of this pathogen.

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Hammond, WP, TC Boone, RE Donahue, LM Souza, and DC Dale. "A comparison of treatment of canine cyclic hematopoiesis with recombinant human granulocyte-macrophage colony-stimulating factor (GM- CSF), G-CSF interleukin-3, and canine G-CSF." Blood 76, no. 3 (1990): 523–32. http://dx.doi.org/10.1182/blood.v76.3.523.523.

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Abstract Cyclic hematopoiesis in gray collie dogs is a stem cell disease in which abnormal regulation of cell production in the bone marrow causes cyclic fluctuations of blood cell counts. In vitro studies demonstrated that recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and granulocyte colony stimulating factor (G-CSF) all stimulated increases in colony formation by canine bone marrow progenitor cells. Based on these results, gray collie dogs were then treated with recombinant human (rh) GM-CSF, IL-3, or G-CSF subcutaneously to test the hypothesis that pharmacologic doses of one of these hematopoietic growth factors could alter cyclic production of cells. When recombinant canine G-CSF became available, it was tested over a range of doses. In vivo rhIL-3 had no effect on the recurrent neutropenia but was associated with eosinophilia, rhGM-CSF caused neutrophilia and eosinophilia but cycling of hematopoiesis persisted. However, rhG-CSF caused neutrophilia, prevented the recurrent neutropenia and, in the two animals not developing antibodies to rhG- CSF, obliterated periodic fluctuation of monocyte, eosinophil, reticulocyte, and platelet counts. Recombinant canine G-CSF increased the nadir neutrophil counts and amplitude of fluctuations at low doses (1 micrograms/kg/d) and eliminated all cycling of cell counts at high doses (5 and 10 micrograms/kg/d). These data suggest significant differences in the actions of these growth factors and imply a critical role for G-CSF in the homeostatic regulation of hematopoiesis.

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Hammond, WP, TC Boone, RE Donahue, LM Souza, and DC Dale. "A comparison of treatment of canine cyclic hematopoiesis with recombinant human granulocyte-macrophage colony-stimulating factor (GM- CSF), G-CSF interleukin-3, and canine G-CSF." Blood 76, no. 3 (1990): 523–32. http://dx.doi.org/10.1182/blood.v76.3.523.bloodjournal763523.

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Cyclic hematopoiesis in gray collie dogs is a stem cell disease in which abnormal regulation of cell production in the bone marrow causes cyclic fluctuations of blood cell counts. In vitro studies demonstrated that recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and granulocyte colony stimulating factor (G-CSF) all stimulated increases in colony formation by canine bone marrow progenitor cells. Based on these results, gray collie dogs were then treated with recombinant human (rh) GM-CSF, IL-3, or G-CSF subcutaneously to test the hypothesis that pharmacologic doses of one of these hematopoietic growth factors could alter cyclic production of cells. When recombinant canine G-CSF became available, it was tested over a range of doses. In vivo rhIL-3 had no effect on the recurrent neutropenia but was associated with eosinophilia, rhGM-CSF caused neutrophilia and eosinophilia but cycling of hematopoiesis persisted. However, rhG-CSF caused neutrophilia, prevented the recurrent neutropenia and, in the two animals not developing antibodies to rhG- CSF, obliterated periodic fluctuation of monocyte, eosinophil, reticulocyte, and platelet counts. Recombinant canine G-CSF increased the nadir neutrophil counts and amplitude of fluctuations at low doses (1 micrograms/kg/d) and eliminated all cycling of cell counts at high doses (5 and 10 micrograms/kg/d). These data suggest significant differences in the actions of these growth factors and imply a critical role for G-CSF in the homeostatic regulation of hematopoiesis.

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Hatori, Kuniyuki, Hajime Honda, and Koichiro Matsuno. "ATP-dependent fluctuations of single actin filaments in vitro." Biophysical Chemistry 58, no. 3 (1996): 267–72. http://dx.doi.org/10.1016/0301-4622(95)00100-x.

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Tokarska, Malgorzata, Hubert Greppin, Claude Penel, and Marc Bonzon. "In Vitro Slow Fluctuation in Horseradish Peroxidase Activity." Chronobiology International 10, no. 4 (1993): 238–43. http://dx.doi.org/10.3109/07420529309059706.

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Tokarska, Malgorzata, Hubert Greppin, Claude Penel, and Marc Bonzon. "In Vitro Slow Fluctuation in Horseradish Peroxidase Activity." Chronobiology International 10, no. 4 (1993): 238–43. http://dx.doi.org/10.1080/07420529309059706.

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21

ARAKAWA, Yohei, Yuusuke NAOI, and Hideyasu SUMIYA. "1003 Vibro Masseur Relaxation Device Using Fluctuation Effect in Transverse lying posture." Proceedings of Ibaraki District Conference 2009 (2009): 257–58. http://dx.doi.org/10.1299/jsmeibaraki.2009.257.

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Qi, Liu, Tang Chao, and Ouyang Qi. "Fluctuation theorem for the mutation process in in vitro evolution." Chinese Physics B 19, no. 4 (2010): 040202. http://dx.doi.org/10.1088/1674-1056/19/4/040202.

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Hirata, Daigo, Toshiki Taba, Masaki Edamatsu, et al. "1P261 Fluctuation analysis of microtubule sliding over kinesin thick filaments in vitro(9. Molecular motor (I),Poster Session,Abstract,Meeting Program of EABS & BSJ 2006)." Seibutsu Butsuri 46, supplement2 (2006): S212. http://dx.doi.org/10.2142/biophys.46.s212_1.

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Henrici, Ryan C., Donelly A. van Schalkwyk, and Colin J. Sutherland. "Transient temperature fluctuations severely decrease P. falciparum susceptibility to artemisinin in vitro." International Journal for Parasitology: Drugs and Drug Resistance 9 (April 2019): 23–26. http://dx.doi.org/10.1016/j.ijpddr.2018.12.003.

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Ivić, Z., Ž. Pržulj, D. Kostić, D. Kapor, and M. Škrinjar. "Effects of quantum lattice fluctuations on vibron pairing in two-site systems." Physical Review B 54, no. 5 (1996): 2992–95. http://dx.doi.org/10.1103/physrevb.54.2992.

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Robertson, Lucy J. "Fluctuations in rat liver alanine-amino-transferase activity during experimental nippostrongylosis." Parasitology 98, no. 2 (1989): 301–6. http://dx.doi.org/10.1017/s0031182000062223.

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SUMMARYThe activity of the gluconeogenic enzyme, alanine-amino-transferase (ALT), in a preparation from the liver of rats was studied by means of an in vitro assay throughout the course of a primary infection of Nippostrongylus brasiliensis, established by a subcutaneous injection of approximately 4000 3rd-stage larvae. The activity was measured on days 1–14 p.i. in both uninfected and infected rats and a marked pattern in the enzyme's activity was observed. In infected rats, the activity increased from 1·46±0·19 U/g liver on day 1 p.i. to a peak on day 4 p.i. of 10·75±1·62 U/g liver, then decreased to a trough of 0·44±0·18 U/g liver on day 10 p.i. before returning to original levels by day 14 p.i., by which time the infection had been largely eliminated. In uninfected rats the activity of the liver enzyme remained constant throughout this period with a value of 2·54±0·12 U/g liver. The activity of the enzyme in vitro was found to be related to the size of the inoculum on days 4 and 10 p.i. It was proposed that these observations could be due to either (1) a direct effect of the parasite, or (2) a consequence of the host immune response to the infection. In order to investigate the second proposition more fully, liver ALT activity was investigated by in vitro assay on selected days p.i. in rats experiencing a secondary N. brasiliensis infection. In these rats the liver ALT activity was observed to reach a peak on day 2 p.i., with an activity of 3·87 ± 0-28 U/g liver, and a trough on day 4 p.i. with an activity of 0·11 ±0·03 U/g liver, returning to similar levels to those measured in uninfected rats by day 7 p.i. When serum prepared from rats having secondary N. brasiliensis infections collected on day 4 p.i. was added to the assay, a reduction in the activity of liver ALT activity from both the infected and uninfected rats was measured by in vitro assay. The results are discussed in relation to protein metabolism and gluconeogenesis in rats infected with N. brasiliensis, and also in relation to the host’s immune response to the parasitic infection.

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Raigorodskaya, M. R., and D. A. Sakharov. "Transcriptome analysis of signaling pathways involved in the formation of intestinal villi in Caco-2 cells." Biotekhnologiya 36, no. 1 (2020): 25–29. http://dx.doi.org/10.21519/0234-2758-2020-36-1-25-29.

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Caco-2 cells are traditionally used to construct in vitro models of the intestinal barrier. One of the characteristics of the mature intestine is the presence of villi, outgrowths of connective tissue covered with epithelial cells. Recently it has been shown that during prolonged cultivation Caco-2 cells form structures resembling intestinal villi. Here, using transcriptome analysis, we showed that BMP and PDGF signaling involved in the formation of villi in vivo significantly altered during the differentiation of Caco-2 cells and, thus, can participate in the formation of similar structures in vitro. In particular, a significant decrease in the expression of the BMP4, BMP7, and BMP8A genes in differentiated cells compared to undifferentiated ones was found. Periodic fluctuations in transepithelial resistance during the differentiation of Caco-2 cells have been discovered for the first time. The period of observed fluctuations indicates that they can arise in the result of cell proliferation during the formation of villi. According to the period of observed fluctuations, one can suppose that they arise in the result of cell proliferation during the formation of villi. impedance spectroscopy, intestine, villi, TEER, BMP, PDGF The study was funded by the Russian Science Foundation (project 16-19-10597).

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Lubejko, Susan T., Bertrand Fontaine, Sara E. Soueidan, and Katrina M. MacLeod. "Spike threshold adaptation diversifies neuronal operating modes in the auditory brain stem." Journal of Neurophysiology 122, no. 6 (2019): 2576–90. http://dx.doi.org/10.1152/jn.00234.2019.

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Single neurons function along a spectrum of neuronal operating modes whose properties determine how the output firing activity is generated from synaptic input. The auditory brain stem contains a diversity of neurons, from pure coincidence detectors to pure integrators and those with intermediate properties. We investigated how intrinsic spike initiation mechanisms regulate neuronal operating mode in the avian cochlear nucleus. Although the neurons in one division of the avian cochlear nucleus, nucleus magnocellularis, have been studied in depth, the spike threshold dynamics of the tonically firing neurons of a second division of cochlear nucleus, nucleus angularis (NA), remained unexplained. The input-output functions of tonically firing NA neurons were interrogated with directly injected in vivo-like current stimuli during whole cell patch-clamp recordings in vitro. Increasing the amplitude of the noise fluctuations in the current stimulus enhanced the firing rates in one subset of tonically firing neurons (“differentiators”) but not another (“integrators”). We found that spike thresholds showed significantly greater adaptation and variability in the differentiator neurons. A leaky integrate-and-fire neuronal model with an adaptive spike initiation process derived from sodium channel dynamics was fit to the firing responses and could recapitulate >80% of the precise temporal firing across a range of fluctuation and mean current levels. Greater threshold adaptation explained the frequency-current curve changes due to a hyperpolarized shift in the effective adaptation voltage range and longer-lasting threshold adaptation in differentiators. The fine-tuning of the intrinsic properties of different NA neurons suggests they may have specialized roles in spectrotemporal processing. NEW & NOTEWORTHY Avian cochlear nucleus angularis (NA) neurons are responsible for encoding sound intensity for sound localization and spectrotemporal processing. An adaptive spike threshold mechanism fine-tunes a subset of repetitive-spiking neurons in NA to confer coincidence detector-like properties. A model based on sodium channel inactivation properties reproduced the activity via a hyperpolarized shift in adaptation conferring fluctuation sensitivity.

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Imafuku, Y., Y. Y. Toyoshima, and K. Tawada. "Fluctuation in the microtubule sliding movement driven by kinesin in vitro." Biophysical Journal 70, no. 2 (1996): 878–86. http://dx.doi.org/10.1016/s0006-3495(96)79631-5.

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Stagner, J. I., and E. Samols. "Perturbation of insulin oscillations by nerve blockade in the in vitro canine pancreas." American Journal of Physiology-Endocrinology and Metabolism 248, no. 5 (1985): E516—E521. http://dx.doi.org/10.1152/ajpendo.1985.248.5.e516.

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The in vitro canine pancreas produces an oscillatory pattern of insulin secretion during a constant glucose concentration despite the lack of external nervous modulation or recirculating hormone feedback. The normal period of insulin fluctuations (7.4 +/- 0.34 min) is unaffected by combined adrenergic and cholinergic blockade by 5 microM atropine, 4 microM propranolol, and 4 microM phentolamine (8.0 +/- 0.31 min, P less than 0.20). To test the theory that the coordination of islet secretion may be controlled by an intrapancreatic nervous system (nonadrenergic, noncholinergic), nerve blockade was attempted by the infusion of tetrodotoxin (TTX) on a background of combined autonomic blockade. TTX infusion resulted in a change in the oscillatory pattern of insulin release by increasing net insulin release and shifting the period of oscillation to 4.5 +/- 0.29 min (P less than 0.0005) at both 88 and 200 mg/dl glucose. These results suggest that an intrinsic autonomously functioning pancreatic nervous system is responsible for the coordination of islet secretion and the production of periodic fluctuations of insulin secretion.

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Bruen, Christine M., Anthony P. Kett, Fiona O'Halloran, et al. "Effect of gelatinisation of starch with casein proteins on incretin hormones and glucose transporters in vitro." British Journal of Nutrition 107, no. 2 (2011): 155–63. http://dx.doi.org/10.1017/s0007114511002698.

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Foods that have a low glycaemic index or foods that contain slowly digestible starch are beneficial in controlling fluctuations in blood glucose and insulin levels. The study hypothesis is that gelatinisation of starch in structured casein networks provides a method for decreasing the digestion rate of the starch and, hence, minimising postprandial glucose fluctuations. This study examined the effect of starch gelatinisation with or without casein on (1) gene expression and peptide secretion levels of the incretin hormones glucagon-like peptide 1 and glucose-independent insulinotropic polypeptide and (2) gene expression of the sodium–glucose cotransporter and GLUT-2 in intestinal cell culture systems. The intestinal epithelial cell line, STC-1, and the enteroendocrine colonic cell line, Caco-2, were exposed to in vitro digested foods (starch gelatinised with α-casein, starch gelatinised with β-casein and gelatinised starch alone). The encapsulation of starch with casein before in vitro digestion lowers levels of incretin hormone secretion. Digestion of starch gelatinised with casein also releases less glucose than starch alone as indicated by significantly (P < 0·05) lower levels of glucose transporter mRNA transcripts. Some subtle cellular response differences were observed following exposure to starch gelatinised with α- compared to β-casein. Fractionation of α-casein and β-casein by reverse-phase HPLC identified that fractions that differed in hydrophobicity differed significantly (P < 0·05) in their ability to promote secretion of the incretin hormones. Evidence suggests that gelatinisation of starch with casein may be a functional food ingredient that minimises blood glucose fluctuations.

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Qian, Nianchao, Atsuhiko Ichimura, Daisuke Takei, et al. "TRPM7 channels mediate spontaneous Ca2+ fluctuations in growth plate chondrocytes that promote bone development." Science Signaling 12, no. 576 (2019): eaaw4847. http://dx.doi.org/10.1126/scisignal.aaw4847.

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During endochondral ossification of long bones, the proliferation and differentiation of chondrocytes cause them to be arranged into layered structures constituting the epiphyseal growth plate, where they secrete the cartilage matrix that is subsequently converted into trabecular bone. Ca2+ signaling has been implicated in chondrogenesis in vitro. Through fluorometric imaging of bone slices from embryonic mice, we demonstrated that live growth plate chondrocytes generated small, cell-autonomous Ca2+ fluctuations that were associated with weak and intermittent Ca2+ influx. Several genes encoding Ca2+-permeable channels were expressed in growth plate chondrocytes, but only pharmacological inhibitors of transient receptor potential cation channel subfamily M member 7 (TRPM7) reduced the spontaneous Ca2+ fluctuations. The TRPM7-mediated Ca2+ influx was likely activated downstream of basal phospholipase C activity and was potentiated upon cell hyperpolarization induced by big-conductance Ca2+-dependent K+ channels. Bones from embryos in which Trpm7 was conditionally knocked out during ex vivo culture exhibited reduced outgrowth and displayed histological abnormalities accompanied by insufficient autophosphorylation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) in the growth plate. The link between TRPM7-mediated Ca2+ fluctuations and CaMKII-dependent chondrogenesis was further supported by experiments with chondrocyte-specific Trpm7 knockout mice. Thus, growth plate chondrocytes generate spontaneous, TRPM7-mediated Ca2+ fluctuations that promote self-maturation and bone development.

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Russo, Vincenzo C., Sandra Higgins, George A. Werther, and Fergus J. Cameron. "Effects of Fluctuating Glucose Levels on Neuronal Cells In Vitro." Neurochemical Research 37, no. 8 (2012): 1768–82. http://dx.doi.org/10.1007/s11064-012-0789-y.

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Orsi, Nicolas M., Nadia Gopichandran, Henry J. Leese, Helen M. Picton, and Sarah E. Harris. "Fluctuations in bovine ovarian follicular fluid composition throughout the oestrous cycle." Reproduction 129, no. 2 (2005): 219–28. http://dx.doi.org/10.1530/rep.1.00460.

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Bovine oocyte maturation in vitro frequently results in abnormal cytoplasmic maturation and failure to acquire developmental competence. This is, in part, likely to be due to the non-physiological nutritional milieu to which oocytes are exposed. Improvements in oocyte developmental potential may be achieved by modelling nutrient profiles on those of preovulatory follicular fluid (FF). However, little is known about fluctuations in FF nutrient levels according to follicle dominance and oestrous cyclicity. This study therefore characterised the carbohydrate and amino acid profile of FF according to these parameters, and compared preovulatory FF composition with that of maturation medium. Carbohydrate concentrations (n = 121) were determined enzymatically whilst amino acid profiles (n = 40) were determined by reverse-phase HPLC. Pyruvate and glucose concentrations were unaffected by follicle dominance, whereas Stage III–IV lactate profiles were higher in non-dominant FF (P < 0.01). While most dominant FF amino acid concentrations were affected by oestrous stage, only glutamate, alanine, leucine and lysine levels fluctuated in non-dominant FF. Glucose and lactate concentrations were significantly negatively correlated, whereas most amino acids were significantly positively correlated with each other. Maturation medium had higher pyruvate and lower lactate concentrations than preovulatory FF (P < 0.001), whereas glucose level was similar. All amino acid levels (except histidine, taurine, alanine and tryptophan) differed significantly between maturation medium and preovulatory FF. These data indicated that FF composition varies throughout the oestrous cycle. Preovulatory FF nutrient profile differed from that of maturation medium, perhaps accounting for the poor developmental competence of in vitro matured oocytes. These data may contribute to the formulation of a nutritionally more physiological maturation medium.

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Hochman, S., and B. J. Schmidt. "Whole Cell Recordings of Lumbar Motoneurons During Locomotor-Like Activity in the In Vitro Neonatal Rat Spinal Cord." Journal of Neurophysiology 79, no. 2 (1998): 743–52. http://dx.doi.org/10.1152/jn.1998.79.2.743.

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Hochman, S. and B. J. Schmidt. Whole cell recordings of lumbar motoneurons during locomotor-like activity in the in vitro neonatal rat spinal cord. J. Neurophysiol. 79: 743–752, 1998. Whole cell current- and voltage-clamp recordings were obtained from lumbar motoneurons in the isolated neonatal rat spinal cord to characterize the behavior of motoneurons during neurochemically induced locomotor-like activity. Bath application of serotonin (10–100 μM) in combination with N-methyl-d-aspartate (1–12 μM) initially produced tonic membrane depolarization (mean = 26 mV), increased input resistance, decreased rheobase, and increased spike inactivation in response to depolarizing current pulse injections. After the initial tonic depolarization, rhythmic fluctuations of the motoneuron membrane potential (locomotor drive potentials; LDPs) developed that were modulated phasically in association with ventral root discharge. The peak and trough voltage levels of the LDP fluctuated above and below the membrane potential recorded immediately before the onset of rhythmic activity. Similarly, firing frequency was modulated above and below prelocomotion firing rates (in those motoneurons that displayed neurochemically induced tonic firing immediately before the onset of rhythmic activity). These observations are consistent with an alternation between phasic excitatory and inhibitory synaptic drives. The amplitude of LDPs and rhythmic excitatory drive current increased with membrane depolarization from −80 to −40 mV and then decreased with further depolarization, thus displaying nonlinear voltage-dependence. Faster frequency, small amplitude voltage fluctuations were observed superimposed on the depolarized phase of LDPs. In some motoneurons, the trajectory of these superimposed fluctuations was consistent with a synaptic origin, whereas in other cells, the regular sinusoidal appearance of the fluctuations and the occurrence of superimposed plateau potentials were more compatible with the activation of an intrinsic membrane property. One motoneuron displayed exclusively excitatory phasic drive, and another motoneuron was characterized by inhibitory phasic drive alone, during rhythmic activity. These findings are compatible with the concept of a central pattern generator that is capable of delivering both excitatory and inhibitory drive to motoneurons during locomotion. The data also suggest that the rhythmic excitatory and inhibitory outputs of the hypothetical half-center model can be dissociated and operate in isolation.

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Noda, Naoki, Yasuhiro Imafuku, Akira Yamada, and Katsuhisa Tawada. "Fluctuation of actin sliding over myosin thick filaments in vitro." BIOPHYSICS 1 (2005): 45–53. http://dx.doi.org/10.2142/biophysics.1.45.

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Tsuruyama, Tatsuaki, Weizhi Liu, and Kenichi Yoshikawa. "In Vitro Murine Leukemia Retroviral Integration and Structure Fluctuation of Target DNA." PLoS ONE 7, no. 2 (2012): e31533. http://dx.doi.org/10.1371/journal.pone.0031533.

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Do, Giap Dang, Hien Thi Dieu Huynh, The Danh Tran, and Tuan Trong Tran. "USING NATURAL LIGHT ON MICROPROPAGATION OF SWEET POTATO ( Ipomoea batatas L. ) IN AREA OF HO CHI MINH CITY." Science and Technology Development Journal 15, no. 3 (2012): 36–46. http://dx.doi.org/10.32508/stdj.v15i3.1845.

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Plantlets of sweet potato ( Ipomoea batatas L. ) were cultured in vitro under three different ambient conditions including a standard culture room - PS, a culture room inside a glasshouse with natural light but controlled temperature - TH, and a standard glasshouse with natural light (natural fluctuations of temperature) - NP. Plantlets from three treatments were compared in terms of pathogen rate, growth, survival plant at the end of the in vitro stage and at the ex vitro acclimatization. This result showed that, after 28 days of culture, sweet potato plants were cultured in vitro TH conditions have reduced entirely due to susceptibility to fungal disease causing outside air. After 14 days of ex vitro acclimatization, plants originally grow in vitro under the TH condition had ability to adapt about field survival and growth rates better than the other two treatments.

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Botte, Ermes, Francesco Biagini, Chiara Magliaro, Andrea Rinaldo, Amos Maritan, and Arti Ahluwalia. "Scaling of joint mass and metabolism fluctuations in in silico cell-laden spheroids." Proceedings of the National Academy of Sciences 118, no. 38 (2021): e2025211118. http://dx.doi.org/10.1073/pnas.2025211118.

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Variations and fluctuations are characteristic features of biological systems and are also manifested in cell cultures. Here, we describe a computational pipeline for identifying the range of three-dimensional (3D) cell-aggregate sizes in which nonisometric scaling emerges in the presence of joint mass and metabolic rate fluctuations. The 3D cell-laden spheroids with size and single-cell metabolic rates described by probability density functions were randomly generated in silico. The distributions of the resulting metabolic rates of the spheroids were computed by modeling oxygen diffusion and reaction. Then, a method for estimating scaling exponents of correlated variables through statistically significant data collapse of joint probability distributions was developed. The method was used to identify a physiologically relevant range of spheroid sizes, where both nonisometric scaling and a minimum oxygen concentration (0.04 mol⋅m−3) is maintained. The in silico pipeline described enables the prediction of the number of experiments needed for an acceptable collapse and, thus, a consistent estimate of scaling parameters. Using the pipeline, we also show that scaling exponents may be significantly different in the presence of joint mass and metabolic-rate variations typically found in cells. Our study highlights the importance of incorporating fluctuations and variability in size and metabolic rates when estimating scaling exponents. It also suggests the need for taking into account their covariations for better understanding and interpreting experimental observations both in vitro and in vivo and brings insights for the design of more predictive and physiologically relevant in vitro models.

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Keenan, Joanne, Karina Horgan, Martin Clynes, et al. "Unexpected fluctuations of trace element levels in cell culture medium in vitro: caveat emptor." In Vitro Cellular & Developmental Biology - Animal 54, no. 8 (2018): 555–58. http://dx.doi.org/10.1007/s11626-018-0285-z.

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41

Martin, Yvan P., and Jean-Luc Bonnefont. "Variations annuelles et identification des Vibrions cultivant à 37 °C dans un effluent urbain, dans des moules et dans l'eau de mer en rade de Toulon (Méditerranée, France)." Canadian Journal of Microbiology 36, no. 1 (1990): 47–52. http://dx.doi.org/10.1139/m90-008.

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Annual variations of vibrios able to proliferate at 37 °C have been studied in various conditions: in urban waste water discharged in the Toulon harbour, in mussels subjected or not to those discharges, and in seawater far from the waste water effluent (for reference). Mean concentration values were nearly similar in the effluent and seawater samples, in the order of 500 bacteria/100 mL, and 400 bacteria/mL in ground mussels, with concentrations showing great variability. In all cases, seasonal abundance fluctuations occurred, with a minimum in winter. A total of 214 vibrio strains were analyzed and identified. The effluent population was the most diversified, including several species of sanitary interest such as Vibrio fluvialis (29.3%), V. cholerae (non O1) (13.4%), and V. metschnikovii (11.0%), as well as other species more typically marine, notably V. alginolyticus (11.0%). In seawater, the latter species was largely represented (48.6%), but other representatives of this genus were also present, such as V. harveyi, V. campbellii, or V. fishcheri; no strain of V. metschnikovii was isolated. The specific composition of the population associated with mussels was similar to that found in seawater. Key words: vibrios, urban sewage, mussels, seawater, annual fluctuations. [Journal translation]

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42

LaPrad, Adam S., Thomas L. Szabo, Béla Suki, and Kenneth R. Lutchen. "Tidal stretches do not modulate responsiveness of intact airways in vitro." Journal of Applied Physiology 109, no. 2 (2010): 295–304. http://dx.doi.org/10.1152/japplphysiol.00107.2010.

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Studies on isolated tracheal airway smooth muscle (ASM) strips have shown that length/force fluctuations, similar to those likely occurring during breathing, will mitigate ASM contractility. These studies conjecture that, solely by reducing length oscillations on a healthy, intact airway, one can create airway hyperresponsiveness, but this has never been explicitly tested. The intact airway has additional complexities of geometry and structure that may impact its relevance to isolated ASM strips. We examined the role of transmural pressure (Ptm) fluctuations of physiological amplitudes on the responsiveness of an intact airway. We developed an integrated system utilizing ultrasound imaging to provide real-time measurements of luminal radius and wall thickness over the full length of an intact airway ( generation 10 and below) during Ptm oscillations. First, airway constriction dynamics to cumulative acetylcholine (ACh) doses (10−7 to 10−3 M) were measured during static and dynamic Ptm protocols. Regardless of the breathing pattern, the Ptm oscillation protocols were ineffective in reducing the net level of constriction for any ACh dose, compared with the static control ( P = 0.225–0.793). Next, Ptm oscillations of increasing peak-to-peak amplitude were applied subsequent to constricting intact airways under static conditions (5.0-cmH2O Ptm) with a moderate ACh dose (10−5 M). Peak-to-peak Ptm oscillations ≤5.0 cmH2O resulted in no statistically significant bronchodilatory response ( P = 0.429 and 0.490). Larger oscillations (10 cmH2O, peak to peak) produced modest dilation of 4.3% ( P = 0.009). The lack of modulation of airway responsiveness by Ptm oscillations in intact, healthy airways suggests that ASM level mechanisms alone may not be the sole determinant of airway responsiveness.

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Faez, Sanli, Sela Samin, Dashdeleg Baasanjav, Stefan Weidlich, Markus Schmidt, and Allard P. Mosk. "Nanocapillary electrokinetic tracking for monitoring charge fluctuations on a single nanoparticle." Faraday Discussions 193 (2016): 447–58. http://dx.doi.org/10.1039/c6fd00097e.

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We introduce nanoCapillary Electrokinetic Tracking (nanoCET), an optofluidic platform for continuously measuring the electrophoretic mobility of a single colloidal nanoparticle or macromolecule in vitro with millisecond time resolution and high charge sensitivity. This platform is based on using a nanocapillary optical fiber in which liquids may flow inside a channel embedded inside the light-guiding core and nanoparticles are tracked using elastic light scattering. Using this platform we have experimentally measured the electrophoretic mobility of 60 nm gold nanoparticles in an aqueous environment. Further, using numerical simulations, we demonstrate the underlying electrokinetic dynamics inside the nanocapillary and the necessary steps for extending this method to probing single biomolecules, which can be achieved with existing technologies. This achievement will immensely facilitate the daunting challenge of monitoring biochemical or catalytic reactions on a single entity over a wide range of timescales. The unique measurement capabilities of this platform pave the way for a wide range of discoveries in colloid science, analytical biochemistry, and medical diagnostics.

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Rudolph, Michael, Zuzanna Piwkowska, Mathilde Badoual, Thierry Bal, and Alain Destexhe. "A Method to Estimate Synaptic Conductances From Membrane Potential Fluctuations." Journal of Neurophysiology 91, no. 6 (2004): 2884–96. http://dx.doi.org/10.1152/jn.01223.2003.

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In neocortical neurons, network activity can activate a large number of synaptic inputs, resulting in highly irregular subthreshold membrane potential ( Vm) fluctuations, commonly called “synaptic noise.” This activity contains information about the underlying network dynamics, but it is not easy to extract network properties from such complex and irregular activity. Here, we propose a method to estimate properties of network activity from intracellular recordings and test this method using theoretical and experimental approaches. The method is based on the analytic expression of the subthreshold Vm distribution at steady state in conductance-based models. Fitting this analytic expression to Vm distributions obtained from intracellular recordings provides estimates of the mean and variance of excitatory and inhibitory conductances. We test the accuracy of these estimates against computational models of increasing complexity. We also test the method using dynamic-clamp recordings of neocortical neurons in vitro. By using an on-line analysis procedure, we show that the measured conductances from spontaneous network activity can be used to re-create artificial states equivalent to real network activity. This approach should be applicable to intracellular recordings during different network states in vivo, providing a characterization of the global properties of synaptic conductances and possible insight into the underlying network mechanisms.

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Hamada, Tomoyo, Fumimasa Nomura, Tomoyuki Kaneko, et al. "Toward quasi-in vivo from in vitro assay (III): Evaluation of temporal field potential duration fluctuation and spatial conduction velocity fluctuation of cardiomyocyte network for in vitro predictive cardiotoxicity measurement." Journal of Pharmacological and Toxicological Methods 68, no. 1 (2013): e25. http://dx.doi.org/10.1016/j.vascn.2013.01.096.

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TANAKA, Takashi, Arata MASUDA, and Akira SONE. "217 Integrity Diagnosis of Bolted Joint Based on Reflectivity Fluctuation Caused by Nonlinear Vibro-acoustic Modulation." Proceedings of the Symposium on Evaluation and Diagnosis 2013.12 (2013): 142–46. http://dx.doi.org/10.1299/jsmesed.2013.12.142.

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Kageyama, T. "In Vitro Evaluation of Pressure Fluctuations with Differing Height of the Infusion Bottle in Phacoemulsification." Japanese Journal of Ophthalmology 44, no. 6 (2000): 690–91. http://dx.doi.org/10.1016/s0021-5155(00)00249-5.

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Stricker, C., A. C. Field, and S. J. Redman. "Statistical analysis of amplitude fluctuations in EPSCs evoked in rat CA1 pyramidal neurones in vitro." Journal of Physiology 490, no. 2 (1996): 419–41. http://dx.doi.org/10.1113/jphysiol.1996.sp021155.

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Turner, Jeffrey W., Leena Malayil, Dominic Guadagnoli, D. Cole, and Erin K. Lipp. "Detection ofVibrio parahaemolyticus,Vibrio vulnificusandVibrio choleraewith respect to seasonal fluctuations in temperature and plankton abundance." Environmental Microbiology 16, no. 4 (2013): 1019–28. http://dx.doi.org/10.1111/1462-2920.12246.

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Balasso, Andrea, Marco Fritzsche, Dieter Liepsch, et al. "High-frequency wall vibrations in a cerebral patient-specific aneurysm model." Biomedical Engineering / Biomedizinische Technik 64, no. 3 (2019): 275–84. http://dx.doi.org/10.1515/bmt-2017-0142.

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Abstract The presence of high-frequency velocity fluctuations in aneurysms have been confirmed by in-vivo measurements and by several numerical simulation studies. Only a few studies have located and recorded wall vibrations in in-vitro experiments using physiological patient models. In this study, we investigated the wall fluctuations produced by a flowing perfusion fluid in a true-to-scale elastic model of a cerebral fusiform aneurysm using a laser Doppler vibrometer (LDV). The model was obtained from patient data. The experimental setup reproduced physiologically relevant conditions using a compliant perfusion system, physiological flow parameters, unsteady flow and a non-Newtonian fluid. Three geometrically identical models with different wall elasticities were used for measurements. The influence of five different flow rates was considered. Wall vibrations were predominantly found at frequencies in the range 40–60 Hz and 255–265 Hz. Their amplitude increased with increasing elasticity of the model, but the spectral peaks remained at about the same frequency. Varying the flow rate produced almost no changes in the frequency domain of the models. The frequency of the spectral peaks varied slightly between points at the lateral wall and at the bottom of the aneurysm. Indeed, embedding the model in a fluid during measurements produced higher and smoother amplitude fluctuations.

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Journal articles on the topic 'Vibro fluctuations'

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