The syntheses of poly (diethylene glycol adipate) in low-intensity ultrasound

Abstract Poly (diethylene glycol adipate) is an important product of chemical technology. Several grades of polyesters (P-9, P-9A) are produced in the industry, in which poly(diethylene glycol adipate) is the main component. These composites are used in production of binders of mixed rocket solid fuels, as well as consumer goods. Poly(diethylene glycol adipate) is obtained by polycondensation of diethylene glycol and adipic acid. Usually, the polycondensation is carried out using catalysts. The use of catalysts complicates this process: requires further purification process or in solvent free system might slow reaction rate due to the limiting diffusion between reactants and mass transfer limitations. Therefore, it was proposed to use low-intensity ultrasound, which allows to influence the kinetics of the process without complicating the system. In this work, the reaction of polycondensation of diethylene glycol and adipic acid in low-intensity ultrasound was studied. The results of applying low-intensity ultrasound to the preparation of poly(diethylene glycol adipate) showed an increase in the reaction rate of the formation of a high-molecular compound and a change in the thermal regime. Application of low-intensity ultrasound provides synchronization of vibration and rotation of self-organizing dissipative structures, which leads to the decrease in energy consumption for mass transfer, thereby increasing the reaction rate. The low-intensity ultrasound demonstrated to be an effective method to intensify the polycondensation reaction.

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Low-intensity ultrasound to induce proliferation and collagen Ι expression of adipose-derived mesenchymal stem cells and fibroblast cells in co-culture

Measurement ◽

10.1016/j.measurement.2020.108280 ◽

2021 ◽

Vol 167 ◽

pp. 108280

Author(s):

Zeinab Hormozi-Moghaddam ◽

Manijhe Mokhtari-Dizaji ◽

Mohammad-Ali Nilforoshzadeh ◽

Mohsen Bakhshandeh

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Fibroblast Cells ◽

Low Intensity ◽

Low Intensity Ultrasound

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EXPERIMENTAL COMPARISON OF MCF7 AND MCF10A RESPONSE TO LOW INTENSITY ULTRASOUND

Journal of Mechanics in Medicine and Biology ◽

10.1142/s021951941950057x ◽

2019 ◽

Vol 19 (06) ◽

pp. 1950057

Author(s):

MARIANTONIETTA IVONE ◽

LUCIANO LAMBERTI ◽

CARMINE PAPPALETTERE ◽

MARIANO FRANCESCO CARATOZZOLO ◽

APOLLONIA TULLO

Keyword(s):

Cell Stiffness ◽

Experimental Comparison ◽

Breast Adenocarcinoma ◽

Mcf7 Cells ◽

Low Intensity ◽

Cell Mortality ◽

The Us ◽

Fixed Power ◽

Breast Cells ◽

Low Intensity Ultrasound

The low-intensity ultrasound effects on MCF7 (human breast adenocarcinoma) and MCF10A (healthy breast cells) have been investigated at different sonication protocol to probe the effectiveness and the selectivity of the ultrasound (US) treatment and to understand the implications between cell mortality, biomechanical interactions and cell elastic modulus. Experiments performed at fixed and variable frequency demonstrated the effectiveness of some protocols in killing carcinogenic cells and the healthy cells insensitivity. Variation of elastic properties of MCF7 cells exposed to US under varying sonication conditions was examined. Sonication was carried out at fixed frequency (as it is usually done in therapy protocols), between 400[Formula: see text]kHz and 620[Formula: see text]kHz, following two protocols: (i) at fixed power output; (ii) at fixed voltage of the US generator. Evolution of cell stiffness during the US treatment was monitored via atomic force spectroscopy (AFS). It was found that cell mortality has a similar trend of variation with respect to sonication frequency regardless of the way specimens are exposed to US. Mechanical properties do not show a uniform trend with respect to frequency, but variations of Young’s modulus are more marked near the very low (400–480) kHz or very high frequencies (580–620) kHz. The observed variations may be related to mechanical interactions occurring in the cell culture, suggesting a primacy of the environment on other factors.

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The reversal of MRP1 expression induced by low-frequency and low-intensity ultrasound and curcumin mediated by VEGF in brain glioma

OncoTargets and Therapy ◽

10.2147/ott.s195205 ◽

2019 ◽

Vol Volume 12 ◽

pp. 3581-3593

Author(s):

Lei Yao ◽

Zhen Zhang

Keyword(s):

Low Frequency ◽

Brain Glioma ◽

Low Intensity ◽

Low Intensity Ultrasound ◽

Mrp1 Expression

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Enhancement of Fracture Healing by Low Intensity Ultrasound

Clinical Orthopaedics and Related Research ◽

10.1097/00003086-199810001-00022 ◽

1998 ◽

Vol 355S ◽

pp. S216-S229 ◽

Cited By ~ 150

Author(s):

Michael Hadjiargyrou ◽

Kenneth McLeod ◽

John P. Ryaby ◽

Clinton Rubin

Keyword(s):

Fracture Healing ◽

Low Intensity ◽

Low Intensity Ultrasound

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Heat/mass transport in shear flow over a heterogeneous surface with first-order surface-reactive domains

Journal of Fluid Mechanics ◽

10.1017/jfm.2015.528 ◽

2015 ◽

Vol 782 ◽

pp. 260-299 ◽

Cited By ~ 8

Author(s):

Preyas N. Shah ◽

Eric S. G. Shaqfeh

Keyword(s):

Mass Transfer ◽

Shear Rate ◽

Shear Flow ◽

Reaction Rate ◽

Patch Size ◽

Patch Area ◽

First Order ◽

Effective Boundary ◽

Order Surface ◽

Slip Distance

Surfaces that include heterogeneous mass transfer at the microscale are ubiquitous in nature and engineering. Many such media are modelled via an effective surface reaction rate or mass transfer coefficient employing the conventional ansatz of kinetically limited transport at the microscale. However, this assumption is not always valid, particularly when there is strong flow. We are interested in modelling reactive and/or porous surfaces that occur in systems where the effective Damköhler number at the microscale can be $O(1)$ and the local Péclet number may be large. In order to expand the range of the effective mass transfer surface coefficient, we study transport from a uniform bath of species in an unbounded shear flow over a flat surface. This surface has a heterogeneous distribution of first-order surface-reactive circular patches (or pores). To understand the physics at the length scale of the patch size, we first analyse the flux to a single reactive patch. We use both analytic and boundary element simulations for this purpose. The shear flow induces a 3-D concentration wake structure downstream of the patch. When two patches are aligned in the shear direction, the wakes interact to reduce the per patch flux compared with the single-patch case. Having determined the length scale of the interaction between two patches, we study the transport to a periodic and disordered distribution of patches again using analytic and boundary integral techniques. We obtain, up to non-dilute patch area fraction, an effective boundary condition for the transport to the patches that depends on the local mass transfer coefficient (or reaction rate) and shear rate. We demonstrate that this boundary condition replaces the details of the heterogeneous surfaces at a wall-normal effective slip distance also determined for non-dilute patch area fractions. The slip distance again depends on the shear rate, and weakly on the reaction rate, and scales with the patch size. These effective boundary conditions can be used directly in large-scale physics simulations as long as the local shear rate, reaction rate and patch area fraction are known.

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A Novel Pore-Scale Thermal-Fracture-Acidizing Model With Heterogeneous Rock Properties

SPE Journal ◽

10.2118/167158-pa ◽

2016 ◽

Vol 21 (01) ◽

pp. 280-292 ◽

Cited By ~ 4

Author(s):

John Lyons ◽

Hadi Nasrabadi ◽

Hisham A. Nasr-El-Din

Keyword(s):

Mass Transfer ◽

Reactive Transport ◽

Reaction Rate ◽

Oil And Gas ◽

Injection Rate ◽

Rock Properties ◽

Thermal Fracture ◽

Pore Scale ◽

Heterogeneous Rock ◽

Acid Reaction

Summary Fracture acidizing is a well-stimulation technique used to improve the productivity of low-permeability reservoirs and to bypass deep formation damage. The reaction of injected acid with the rock matrix forms etched channels through which oil and gas can then flow upon production. The properties of these etched channels depend on the acid-injection rate, temperature, reaction chemistry, mass-transport properties, and formation mineralogy. As the acid enters the formation, it increases in temperature by heat exchange with the formation and the heat generated by acid reaction with the rock. Thus, the reaction rate, viscosity, and mass transfer of acid inside the fracture also increase. In this study, a new thermal-fracture-acidizing model is presented that uses the lattice Boltzmann method to simulate reactive transport. This method incorporates both accurate hydrodynamics and reaction kinetics at the solid/liquid interface. The temperature update is performed by use of a finite-difference technique. Furthermore, heterogeneity in rock properties (e.g., porosity, permeability, and reaction rate) is included. The result is a model that can accurately simulate realistic fracture geometries and rock properties at the pore scale and that can predict the geometry of the fracture after acidizing. Three thermal-fracture-acidizing simulations are presented here, involving injection of 15 and 28 wt% of hydrochloric acid into a calcite fracture. The results clearly show an increase in the overall fracture dissolution because of the addition of temperature effects (increasing the acid-reaction and mass-transfer rates). It has also been found that by introducing mineral heterogeneity, preferential dissolution leads to the creation of uneven etching across the fracture surfaces, indicating channel formation.

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