Symphonies of Growth: Unveiling the Impact of Sound Waves on Plant Physiology and Productivity.

The application of sound wave technology to different plant species has revealed that variations in the Hz, sound pressure intensity, treatment duration, and type of setup of the sound source significantly impact the plant performance. A study conducted on cotton plants treated with Plant Acoustic Frequency Technology (PAFT) highlighted improvements across various growth metrics. In particular, the treated samples showed increases in the height, size of the fourth expanded leaf from the final one, count of branches carrying bolls, quantity of bolls, and weight of individual bolls. Another study showed how the impact of a 4 kHz sound stimulus positively promoted plant drought tolerance. In other cases, such as in transgenic rice plants, GUS expression was upregulated at 250 Hz but downregulated at 50 Hz. In the same way, sound frequencies have been found to enhance the osmotic potential, with the highest observed in samples treated with frequencies of 0.5 and 0.8 kHz compared to the control. Furthermore, a sound treatment with a frequency of 0.4 kHz and a sound pressure level (SPL) of 106 dB significantly increased the paddy rice germination index, as evidenced by an increase in the stem height and relative fresh weight. This paper presents a complete, rationalized and updated review of the literature on the effects of sound waves on the physiology and growth parameters of sound-treated plants.

Investigating the effect of acoustic waves on spoilage fungal growth and shelf life of strawberry fruit.

The effects of acoustic waves on growth inhibition of food spoilage fungi (Aspergillus niger, Aspergillus flavus, Aspergillus parasiticus and Botrytis cinerea) on the medium and strawberry surfaces were investigated. Firstly, single-frequency sound waves (250, 500, 1000, 2000, 4000, 8000, 12,000 and 16,000 Hz) were induced on inoculated medium with fungi spores for 24 h and growth diameter of each mold was evaluated during the incubation period. In the second stage, the sound waves with two frequencies of 250 Hz and 16,000 Hz were induced on inoculated strawberries with fungi spores at 5 °C for different times (2, 4, 6, 8 and 10 days). The results from the first stage indicated that the sound waves inhibited the growth of A. niger (20.02%) at 250 Hz and B. cinerea (4/64%) at 4000 Hz on potato dextrose agar (PDA) surface. Also, comparison of the growth diameter of some species of Aspergillus revealed various responses in presence of 250 Hz frequency. In the second stage, applying a frequency of 250 Hz over a period of 10 days proved to be more effective in inhibiting the growth of A. niger and B. cinerea on strawberries inoculated with fungal spores. Consequently, the shelf lives of the strawberries significantly increased to 26 days and 18 days, respectively, under this treatment. Based on the findings, it is concluded that sounding with acoustic waves can be used as a green and cheap technology along with other technologies to improve food safety.

The influence of sound waves and musical experiences on movement coordination with beats.

Synchronizing movement with external stimuli is important in musicians and athletes. This study investigated the effects of sound characteristics, including sound with harmonics (square wave) and without harmonics (sine wave) and levels of expertise in sports and music on rhythmic ability. Thirty-two university students participated in the study. The participants were divided into sixteen music education (ME) and sixteen physical education (PE) majors. They were asked to perform finger tapping tasks with 1,2 and 3 Hz beat rates, tapping in time with the sine and square wave beat produced by a metronome. The relative phase angle of finger tapping and the onset time of metronome sound were calculated using circular statistics. The results showed that type of wave and music experience affected the rhythmic ability of participants. Our study highlights the importance of types of waves on rhythmic ability, especially for participants with no background in music. The square wave is recommended for athletes to learn to synchronize their movement with beats.

Acoustomicrofluidic Defect Engineering and Ligand Exchange in ZIF-8 Metal-Organic Frameworks.

A way through which the properties of metal-organic frameworks (MOFs) can be tuned is by engineering defects into the crystal structure. Given its intrinsic stability and rigidity, however, it is difficult to introduce defects into zeolitic imidazolate frameworks (ZIFs)-and ZIF-8, in particular-without compromising crystal integrity. In this work, it is shown that the acoustic radiation pressure as well as the hydrodynamic stresses arising from the oscillatory flow generated by coupling high frequency (MHz-order) hybrid surface and bulk acoustic waves into a suspension of ZIF-8 crystals in a liquid pressure transmitting medium is capable of driving permanent structural changes in their crystal lattice structure. Over time, the enhancement in the diffusive transport of guest molecules into the material's pores as a consequence is shown to lead to expansion of the pore framework, and subsequently, the creation of dangling-linker and missing-linker defects, therefore offering the possibility of tuning the type and extent of defects engineered into the MOF through the acoustic exposure time. Additionally, the practical utility of the technology is demonstrated for one-pot, simultaneous solvent-assisted ligand exchange under ambient conditions, for sub-micron-dimension ZIF-8 crystals and relatively large ligands-more specifically 2-aminobenzimidazole-without compromising the framework porosity or overall crystal structure.

Relative Humidity Measurement of Air in Low-Temperature Ranges Using Low-Frequency Acoustic Waves and Correlation Signal Processing Techniques.

Air relative humidity (RH) is an important control parameter in many industrial processes. The acoustic method is a novel technique to measure air humidity non-intrusively. Relevant research is limited. Existing methods use ultrasonic waves as a sound source and air humidity is measured by measuring the sound attenuation. In this paper, a novel air humidity measurement system using low-frequency sound waves as a sound source and two acoustic sensors is proposed. Air humidity is acquired by measuring sound speed in the air. Sound speed mainly depends on air temperature, humidity, atmospheric pressure, and air composition. The influence of air temperature, atmospheric pressure, and air constituent concentrations on the RH measurement is analyzed theoretically. A 0.1 s linear chirp signal in the frequency range of 200-500 Hz is selected as the sound source. Sound travel time is calculated by cross-correlating the sound signals received by the two acoustic sensors. To improve the accuracy of the sound speed measurement, sound speed under different RH points is obtained through reference RH experiments and substituted into the calibration equation. Then, equivalent sound path length and systematic delay are estimated using the least squares method. After obtaining these two parameter values, the sound speed measured by the system is closer to the theoretical value at the same RH point. In validation experiments using RH measured by a thermo-hygrometer as a comparison, the relative errors of the acoustically measured RH are within 9.9% in the RH range of 40.7-87.1%, and the standard deviation is within 4.8%.

Radial shockwave treatment promotes chondrogenesis in human growth plate and longitudinal bone growth in rabbits.

OBJECTIVE: The process of longitudinal bone growth occurs at the growth plate where the chondrocytes undergo apparent structural and molecular changes to promote growth. Recent reports suggest that radial shockwave treatment (rSWT) stimulates bone length in cultured fetal rat metatarsals. Therefore, we investigated if rSWT has similar growth promoting effects on cultured human growth plate fragments and addressed the same in a preclinical in vivo rabbit model by subjecting their growth plates to rSWT. METHODS: Short-term effects of high-energy rSWT were evaluated in a unique model of cultured human growth plate cartilage (n = 5) wherein samples exposed to rSWT were assessed for chondrogenic markers at 24 h in comparison to unexposed samples obtained from the same limb. Local in vivo effects were studied in six-week-old rabbits who had their distal femurs exposed to four weekly sessions of rSWT at low- and high-energy levels (n = 4 each). At sacrifice, histomorphometric and immunohistochemistry analyses were performed. For effect on longitudinal growth, proximal tibiae of 22-week-old rabbits (n = 12) were asymmetrically exposed to rSWT; the contralateral side served as untreated controls. At sacrifice, the final bone length was measured. RESULTS: In the ex vivo model of cultured human growth plate cartilage, rSWT exposure upregulated SOX9 and COL2A1 compared to control. In the immature rabbit model, an increased number of proliferative chondrocytes and column density was seen for both the energy levels. In the adolescent rabbits, an increase in tibial length was observed after the fourth session of high-energy rSWT and until six-weeks after rSWT compared to the untreated limb. CONCLUSIONS: Our preliminary experimental results suggest that rSWT may serve as a non-invasive treatment and possibly a safe strategy to stimulate longitudinal bone growth. However, further studies are needed to assess the in vivo effects of rSWT in models of disturbed bone growth.

The Effect of Music on Livestock: Cattle, Poultry and Pigs.

The welfare of animals, especially those kept in intensive production systems, is a priority for modern agriculture. This stems from the desire to keep animals healthy, to obtain a good-quality final product, and to meet the demands of today's consumers, who have been increasingly persuaded to buy organic products. As a result, new sound-based methods have been pursued to reduce external stress in livestock. Music therapy has been known for thousands of years, and sounds were believed to improve both body and spirit. Today, they are mostly used to distract patients from their pain, as well as to treat depression and cardiovascular disorders. However, recent studies have suggested that appropriately selected music can confer some health benefits, e.g., by increasing the level and activity of natural killer cells. For use in livestock, the choice of genre, the loudness of the music and the tempo are all important factors. Some music tracks promote relaxation (thus improving yields), while others have the opposite effect. However, there is no doubt that enriching the animals' environment with music improves their welfare and may also convince consumers to buy products from intensively farmed animals. The present paper explores the effects of music on livestock (cattle, poultry and pigs) on the basis of the available literature.

Estimation of Cavities beneath Plate Structures Using a Microphone: Laboratory Model Tests.

The objective of this study is to detect a cavity and estimate its size using sound waves in a laboratory model chamber filled with dry sand. One side of the chamber is covered with an acrylic plate, and a cavity is placed between the plate and sand. Sound waves are generated by impacting the plate with an instrumented hammer, and are measured using a microphone. The measured sound waves are analyzed with four comprehensive analyses including the measured area under the rectified signal envelope (MARSE) energy, flexibility, peak magnitude of wavelet transform, and frequency corresponding to the peak magnitude. The test results show that the accuracy of cavity detection using the MARSE energy is higher for thicker plates, whereas that using flexibility is higher for thinner plates. The accuracies of cavity detection using the peak magnitude of wavelet transform, and frequency corresponding to the peak magnitude are consistently high regardless of the plate thickness. Moreover, the cavity size may be under- or overestimated depending on the plate thickness and the selected analysis method. The average of the cavity sizes estimated by these methods, however, is slightly larger than the actual cavity size regardless of the plate thickness. This study demonstrates that microphones may be effectively used for the identification of a cavity and the estimation of its size.

Sounds Stimulation on In Vitro HL1 Cells: A Pilot Study and a Theoretical Physical Model.

Mechanical vibrations seem to affect the behaviour of different cell types and the functions of different organs. Pressure waves, including acoustic waves (sounds), could affect cytoskeletal molecules via coherent changes in their spatial organization and mechano-transduction signalling. We analyzed the sounds spectra and their fractal features. Cardiac muscle HL1 cells were exposed to different sounds, were stained for cytoskeletal markers (phalloidin, beta-actin, alpha-tubulin, alpha-actinin-1), and studied with multifractal analysis (using FracLac for ImageJ). A single cell was live-imaged and its dynamic contractility changes in response to each different sound were analysed (using Musclemotion for ImageJ). Different sound stimuli seem to influence the contractility and the spatial organization of HL1 cells, resulting in a different localization and fluorescence emission of cytoskeletal proteins. Since the cellular behaviour seems to correlate with the fractal structure of the sound used, we speculate that it can influence the cells by virtue of the different sound waves' geometric properties that we have photographed and filmed. A theoretical physical model is proposed to explain our results, based on the coherent molecular dynamics. We stress the role of the systemic view in the understanding of the biological activity.

Arrays Formation of Zinc Oxide Nano-Objects with Varying Morphology for Sensor Applications.

The regularities and features of the formation of arrays of zinc oxide nano-objects with varying morphology are determined by CO2 laser processing with intensification of diffusion processes in the solid state of Cu-Zn metallic materials which are selectively oxidizable. In the process of laser treatment in air using the synergy of heat exposure and vibrations induced by laser with a force fundamental frequency of 100 Hz, the brass surface of samples is oxidized mainly with the generation of ZnO nanowires. The condition for intensification is the local non-stationary deformation caused by sound waves induced by laser. Upon the initiation of the processes of exfoliation of the initially formed layers on the material surface, apart from a disordered structure, a structure was formed in the central region containing two-dimensional objects made of zinc oxide with characteristic thicknesses of 70-100 nm. Such arrays can provide the potential to create a periodic localized electric field applying direct current, this allows the production of electrically switched diffraction gratings with a variable nature of zones. It has been established that during laser pulse-periodic irradiation on brass, the component of the metal alloy, namely, zinc, will oxidize on the surface in the extent that its diffusion to the surface will be ensured. During laser pulse-periodic heating under conditions of the experiment, the diffusion coefficient was 2-3 times higher than from direct heating and exposure to a temperature of 700 °C. The study of the electrical resistance of the created samples by the contact probe method was performed by the four-point probe method. It was determined that the specific electrical resistance at the center of the sample was 30-40% more than at the periphery. To determine the possibility of using the obtained material based on zinc oxide for the creation of sensors, oxygen was adsorbed on the sample in an oxygen-argon mixture, and then the electrical resistance in the central part was measured. It was found that the adsorbed oxygen increases the electrical resistivity of the sample by 70%. The formation of an oxide layer directly from the metal substrate can solve problem of forming an electrical contact between the gas-sensitive oxide layer and this substrate.

Sound Velocities of Lennard-Jones Systems Near the Liquid-Solid Phase Transition.

Longitudinal and transverse sound velocities of Lennard-Jones systems are calculated at the liquid-solid coexistence using the additivity principle. The results are shown to agree well with the "exact" values obtained from their relations to excess energy and pressure. Some consequences, in particular in the context of the Lindemann's melting rule and Stokes-Einstein relation between the self-diffusion and viscosity coefficients, are discussed. Comparison with available experimental data on the sound velocities of solid argon at melting conditions is provided.

Sound perception in plants.

Can plants perceive sound? And what sounds are they likely to be "listening" to? The environment of plants includes many informative sounds, produced by biotic and abiotic sources. An ability to respond to these sounds could thus have a significant adaptive value for plants. We suggest the term phytoacoustics to describe the emerging field exploring sound emission and sound detection in plants, and review the recent studies published on these topics. We describe evidence of plant responses to sounds, varying from changes in gene expression to changes in pathogen resistance and nectar composition. The main focus of this review is the effect of airborne sounds on living plants. We also review work on sound emissions by plants, and plant morphological adaptations to sound. Finally, we discuss the ecological contexts where response to sound would be most advantageous to plants.

The assessment of tomato fruit quality parameters under different sound waves.

Sound stress is an abiotic stress factor wherein the sound wave form affects the growth and development of plants as an alternative mechanical stress. To explore this, 10-week-old tomato (Solanum lycopersicum) plants were used in this experiment. The tomato plants were exposed to three different frequency values consecutively: 600 Hz in the first week, 1240 Hz in the second week and 1600 Hz in the third week. The decibel (dB) value was adjusted to 90 dB in the sound amplifier. At the end of the experiment, lycopene, vitamin C, total sugar, total acid and total phenol levels were analysed and pH and 0Brix were measured in tomato fruits. As a result, it was determined that as the sound frequency intensity level increased, the concentration of fruit parameters also increased: lycopene, vitamin C, total sugar, total acid and total phenol. The total phenol content, lycopene content and ascorbic acid of the tomato plants that were exposed to sound waves at different frequencies increased at a rate of 70%, 20% and 14%, respectively. According to the results of all measured parameters in tomato fruits, 1600 Hz has been determined the best of sound wave frequency value.

Competing Lagrangians for incompressible and compressible viscous flow.

A recently proposed variational principle with a discontinuous Lagrangian for viscous flow is reinterpreted against the background of stochastic variational descriptions of dissipative systems, underpinning its physical basis from a different viewpoint. It is shown that additional non-classical contributions to the friction force occurring in the momentum balance vanish by time averaging. Accordingly, the discontinuous Lagrangian can alternatively be understood from the standpoint of an analogous deterministic model for irreversible processes of stochastic character. A comparison is made with established stochastic variational descriptions and an alternative deterministic approach based on a first integral of Navier-Stokes equations is undertaken. The applicability of the discontinuous Lagrangian approach for different Reynolds number regimes is discussed considering the Kolmogorov time scale. A generalization for compressible flow is elaborated and its use demonstrated for damped sound waves.

Sound Waves Induce Neural Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells via Ryanodine Receptor-Induced Calcium Release and Pyk2 Activation.

Mesenchymal stem cells (MSCs) have shown considerable promise as an adaptable cell source for use in tissue engineering and other therapeutic applications. The aims of this study were to develop methods to test the hypothesis that human MSCs could be differentiated using sound wave stimulation alone and to find the underlying mechanism. Human bone marrow (hBM)-MSCs were stimulated with sound waves (1 kHz, 81 dB) for 7 days and the expression of neural markers were analyzed. Sound waves induced neural differentiation of hBM-MSC at 1 kHz and 81 dB but not at 1 kHz and 100 dB. To determine the signaling pathways involved in the neural differentiation of hBM-MSCs by sound wave stimulation, we examined the Pyk2 and CREB phosphorylation. Sound wave induced an increase in the phosphorylation of Pyk2 and CREB at 45 min and 90 min, respectively, in hBM-MSCs. To find out the upstream activator of Pyk2, we examined the intracellular calcium source that was released by sound wave stimulation. When we used ryanodine as a ryanodine receptor antagonist, sound wave-induced calcium release was suppressed. Moreover, pre-treatment with a Pyk2 inhibitor, PF431396, prevented the phosphorylation of Pyk2 and suppressed sound wave-induced neural differentiation in hBM-MSCs. These results suggest that specific sound wave stimulation could be used as a neural differentiation inducer of hBM-MSCs.

Bubbles with shock waves and ultrasound: a review.

The study of the interaction of bubbles with shock waves and ultrasound is sometimes termed 'acoustic cavitation'. It is of importance in many biomedical applications where sound waves are applied. The use of shock waves and ultrasound in medical treatments is appealing because of their non-invasiveness. In this review, we present a variety of acoustics-bubble interactions, with a focus on shock wave-bubble interaction and bubble cloud phenomena. The dynamics of a single spherically oscillating bubble is rather well understood. However, when there is a nearby surface, the bubble often collapses non-spherically with a high-speed jet. The direction of the jet depends on the 'resistance' of the boundary: the bubble jets towards a rigid boundary, splits up near an elastic boundary, and jets away from a free surface. The presence of a shock wave complicates the bubble dynamics further. We shall discuss both experimental studies using high-speed photography and numerical simulations involving shock wave-bubble interaction. In biomedical applications, instead of a single bubble, often clouds of bubbles appear (consisting of many individual bubbles). The dynamics of such a bubble cloud is even more complex. We shall show some of the phenomena observed in a high-intensity focused ultrasound (HIFU) field. The nonlinear nature of the sound field and the complex inter-bubble interaction in a cloud present challenges to a comprehensive understanding of the physics of the bubble cloud in HIFU. We conclude the article with some comments on the challenges ahead.

Lifetime comparison of Y-TZP/porcelain crowns under different loading conditions.

OBJECTIVES: To compare the lifetime of Y-TZP/porcelain crowns under three different load conditions using step-stress accelerated lifetime testing. METHODS: The Y-TZP frameworks were milled using CAD/CAM, veneered with a porcelain and cemented onto dentine analogue dies. Specimens were divided according to the occlusal load condition (n=20): central fossa load (CFL), cusp tip load (CTL) and sliding contact (SC). For CFL and CTL, the cyclic load was applied parallel to the long axis of the preparation using a ceramic piston. For SC, the axial load was associated to 1mm lateral displacement at the disto-lingual cusp. Different stress profiles were used. Failures were detected with an acoustic system. A Weibull distribution (95% confidence boundary) was used to analyse the data, and fractographic principles were used to evaluate fractured specimens. RESULTS: The acoustic monitor was able to detect the initial crack. The probability of failure (at 300 N load and 200,000 cycles) was statistically greater for CTL (0.63; 0.44-0.81) compared to CFL (0.23; 0.12-0.43). The Weibull modulus of CFL (2.1; 1.5-3.6) was greater than for SC (0.7; 0.5-1.2), with no difference in the lifetime. All specimens failed by chipping, which originated predominantly at the contact (66.7%) on CTL, and in the bulk of the porcelain on CFL (100%) and SC (80%). CONCLUSIONS: Contact at the cusp tip is more harmful than at the central fossa. Data from sliding contact are less consistent than from axial contacts, but more clinically relevant. CLINICAL SIGNIFICANCE: The loading condition of Y-TZP/porcelain crowns can influence on the probability of failure and failure mode. The contact at the cusp tip is more harmful than at the central fossa, where the stress is better distributed. Sliding contact is a better simulator of the chewing cycle compared to axial contacts.

Evidence for two-dimensional solitary sound waves in a lipid controlled interface and its implications for biological signalling.

Biological membranes by virtue of their elastic properties should be capable of propagating localized perturbations analogous to sound waves. However, the existence and the possible role of such waves in communication in biology remain unexplored. Here, we report the first observations of two-dimensional solitary elastic pulses in lipid interfaces, excited mechanically and detected by FRET. We demonstrate that the nonlinearity near a maximum in the susceptibility of the lipid monolayer results in solitary pulses that also have a threshold for excitation. These experiments clearly demonstrate that the state of the interface regulates the propagation of pulses both qualitatively and quantitatively. Finally, we elaborate on the striking similarity of the observed phenomenon to nerve pulse propagation and a thermodynamic basis of cell signalling in general.

To the non-local theory of cold nuclear fusion.

In this paper, we revisit the cold fusion (CF) phenomenon using the generalized Bolzmann kinetics theory which can represent the non-local physics of this CF phenomenon. This approach can identify the conditions when the CF can take place as the soliton creation under the influence of the intensive sound waves. The vast mathematical modelling leads to affirmation that all parts of soliton move with the same velocity and with the small internal change of the pressure. The zone of the high density is shaped on the soliton's front. It means that the regime of the 'acoustic CF' could be realized from the position of the non-local hydrodynamics.