Ultrasound-assisted cell

The general experimental procedure employed in the study here has been described previously (7), thus only a brief overview is presented here. For all experiments, 45 mL deionized water and catalyst (50 mg Pd-black for 3-buten-2-ol and 25 mg for l,4-pentadien-3-ol) were added to the reaction cell. For ultrasound-assisted, as well as stirred (blank) experiments, the catalyst was reduced with hydrogen (6.8 atm) in water for 5 minutes at an average power of 360 W (electrical 90% amplitude). The reagents (320 mg 3-buten-2-ol or 360 mg l,4-pentadien-3-ol) were added to the reduced catalyst solution to achieve... 

Doping is important for semiconductors in order to tune their optical and electrical properties for the potential applications in biotechnology and solar cells [65]. Ag-doped hexagonal CdS nanoparticles were successfully obtained by an ultrasound-assisted microwave synthesis method. Here, the doping of Ag in to CdS nanoparticles induced the evolution of crystal structure from cubic to hexagonal. Further support from photocatalytic experiment also clearly indicates the doping of Ag clusters into the CdS matrix. 

Figure 4.2. Sample cells for continuous ultrasound-assisted leaching. (A) One-piece cell and (B) DIsmountable cell. (Reproduced with permission of Elsevier, Ref [2].)...

Figure 4.6. Coupling of continuous ultrasound-assisted leaching and detection in an open (A) and a closed manifold with the detection system in the circuit for monitoring the leaching process (B). C — coil, D — debubbler, DS — detection system, FC — flow cell, L- leachant, LC — leaching chamber, PC — personal computer, PL — propagating liquid, PP — peristaltic pump, SV— switching valve, UP— ultrasonic probe, 1/1/— waste and WB — water bath.

The variables to be optimized in a continuous ultrasound-assisted leaching approach can be classified into two groups, namely those concerning the relative position of the probe and sample cell and their surroundings, and those related to the sonicator settings. 

Diverse Water, whole blood, culture cells Ultrasound-assisted filtration UV-Vis Diverse Multi-commuted flow injection system with three parallel analytical paths pressurised gas as the fluid propellent [150]... 

Wu, J., Lin, L., and Chau, F. 2001. Ultrasound-assisted extraction of ginseng saponins from ginseng roots and cultured ginseng cells. Ultrason. Sonochem. 8 347-352. 

Fig. 5.15 Scanningelectron microscopy images ofalbedo cells obtained from orange peel in case of (a) hot-air drying and (b) ultrasound-assisted hot-air drying. Illustration courtesyof Prof. Antonio Mulet and Juan A. Carcel, Universidad Polit nica de Valencia, Spain.

As water is entrapped in the intact cells of a plant tissue, ultrasound-mediated effects depend on cell damage due to enhanced dehydration. It is likely, that a cell disintegration by PEF prior to ultrasound-assisted drying would make the... 

The latest studies analyzing the mechanisms of contact ultrasound-assisted mass transfer have revealed that ultrasound-related cell disruption is limited to the thin layer of tissue that is in direct contact with the vibrating surface. In any tissue layers deeper than 1 mm, the structural changes that occur are attributed to water removal moreover, ultrasound can enhance such water removal as a result of mechanical effects that can loosen cell-boundary layers, and remove moisture from solid-liquid interfaces. The transport of moisture through the pore network can also be increased, and low-pressure cycles vhll enable an improved evaporation in the tissues. 

Parameter optimization in efficient processes is much more difficult when ultrasound is transmitted using liquids, as in the case of ultrasound-assisted osmotic dehydration. The strong physical and chemical effects of cavitation can easily cause cell disruption, with an associated loss of tissue firmness, leakage, and oxidation. 

The use of auxiliary energies to accelerate or increase the extraction efficiency of OBPs from OIW has scarcely been explored even though ultrasound and superheated extractants have been found to result in improved extraction. An attempt to extract BPs from alpemjo was made by using the continuous ultrasound-assisted method based on the approach illustrated in Figure 4.11, where the sample, held in the extraction chamber, was subjected to the action of an ultrasound probe meanwhile, the extractant (1 3 methanol-water) was recirculated in a closed circuit to ensure adequate mass transfer to the liquid phase under optimal working conditions. The direction of the extractant was changed at 40 s intervals to minimize dilution of the extract and compaction in the extraction cell, which could result in overpressure in the dynamic system [268]. 

Bandyopadhyay et al. [50] synthesized a series of novel N-substituted pyrrole derivatives. The autiiors sought a simple and solvent-free ultrasound-assisted reaction for tiie synthesis of N-substituted pyrroles (12) by reacting 2,5-dime-thoxytetrahydrofuran (10) with aromatic, aliphatic, polyaromatic, and heteropolyaromatic amines (11) using bismuth nitrate pentahydrate as catalyst (Scheme 4). It should be mentioned that the addition of the bismuth salt, which is environmentally benign and nontoxic, increased tiie reaction yield from 55% to 99% and reduced the reaction time from 5h to 5 min. 5-(lH-Pyrrol-l-yl)-l,10-phenantiiroline and l-(phenanthren-2-yl)-lH-pyrrole have demonstrated cytotoxic specificity against liver cancer cell lines in vitro when compared with normal cultured primary hepatocytes. 

The irradiation of a system with sound waves (usually ultrasound). Often used to disrupt cell membranes and in early steps in protein purification, it should also be noted that sonication can increase rates of reaction as well as assist in the preparation of vesicles. 

Figure 2.4. Commercial discrete devices for chemical reactions assisted by ultrasound probes. (A) Rosett cell, (B) indented cell, (C) Suslick cell and (D) cup horn.

Figure 2.8. Continuous-flow laboratory manifolds for US-assisted processes. (A) One-way system for liquid-liquid extraction, (B) Open, one- or two-way leaching system and (C) Closed, one- or two-way leaching system. C — coil, CR — collection reservoir, IV — injeotion valve, LP — liquid phase, PC — personal computer, PL — propagating liquid, PP — peristaltic pump, SC — sample cell, SL — sample loop, S / — switohing value, UP — ultrasound probe and WB — water bath.

Ultrasonic-assisted extraction (UAE) is the other common method that accelerates the extraction process [83]. The principle behind the UAE is similar to MAE, where the cell wall is destroyed by ultrasound that leads to active constituents being leached out from ruptured cells without modifying the polysaccharides. In general, UAE is able to extract polysaccharides at lower temperatures, which is about 25-70 °C at 120/300 W of ultrasonic power [89]. The extraction time is between 5 and 40 min. 

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