Improving the swelling capacity of granular cold-water rice starch by ultrasound-assisted alcoholic-alkaline treatment

The aim of this study was to determine the ability to improve the capacity of cold swelling and cold-water solubility of rice starch by ultrasonic-assisted alcohol-alkaline and alcohol-alkaline methods. To achieve this, ultrasound powers (U) were varied (30%, 70%, 100%) under the granular cold-water swelling starch (GCWSS) preparation (GCWSS + 30 %U, GCWSS + 70 %U, and GCWSS + 100 %U). The effects of these methods on morphological, pasting properties, amylose content, ratio of 1047/1022 spectra by FTIR, turbidity, freeze-thaw stability, and gel texture were also studied and compared. The results showed that the surface of GCWSS granules presented a honeycomb especially GCWSS + U treatments exhibited more porous on the surface of starch granules. The cold swelling power and solubility of GCWSS + U samples were increased which confirmed by reducing ratio of ordered structure to amorphous structure of starch, and turbidity was also decreased. Moreover, pasting temperature, breakdown, final viscosity, and setback decreased while peak viscosity increased as measured using a Rapid Visco Analyzer. The freeze-thaw stability of GCWSS + U was more resistant to syneresis than GCWSS under repeated freeze-thaw cycles. The reduction of gel hardness and springiness was observed using Texture Analyzer. These changes were enhanced with increasing ultrasound powers. Thus, the results indicate that the different ultrasound-assisted alcohol-alkaline treatments for preparing GCWSS show an effective use in the preparation of GCWSS with improved cold-water swelling and reduced retrogradation of rice starch.

Evaluation of the ethanolic ultrasound-assisted extraction from clove (Syzygium aromaticum) leaves and chemical characterization of the extracts

In this study, clove leaves (Syzygium aromaticum) were subjected to ultrasound-assisted extraction (UAE) with ethanol as the solvent, following a central composite design to evaluate the effects of time, amplitude, solvent/sample ratio, and temperature on the yield, eugenol content, and antioxidant capacity of the extracts. The results were compared with those obtained using the conventional method of maceration (ME). The optimum conditions for extract yield were achieved with an extraction time of 25 min,amplitude of 85%, solvent/sample ratio of 35 mL g^-1, and temperature of 70 °C, and the result (14.63 wt%) was three times higher than that of conventional extraction. Eugenol was detected in the extracts obtained by both methods, with the highest yield of 2.94 g eugenol kg leaves^-1obtained in the UAE method, while the ME method achieved 1.36 g eugenol kg leaves^-1.In general, the extracts exhibited high antioxidant capacities.

Ultrasound-assisted transesterification of soybean oil using low power and high frequency and no external heating source

In this work, high frequency and low power ultrasound without external heating source and mechanical stirring in biodiesel production were studied. Transesterification of soybean oil with methanol and catalyzed by KOH was investigated using ultrasound equipment and ultrasonic transducer. The effect of ultrasonic output power (3 W-9 W), ultrasonic frequency (1 MHz and 3 MHz), and alcohol to oil molar ratio (6:1 and 8:1) have been investigated. The increase in ultrasonic power provided higher conversion rates. In addition, higher conversion rates were obtained by increasing the ultrasonic frequency from 1 MHz to 3 MHz (48.7% to 79.5%) for the same reaction time. Results also indicate that the speed of sound can be used to evaluate the produced biodiesel qualitatively. Further, the ultrasound system presented electric consumption (46.2W∙h) four times lower than achieved using the conventional method (211.7W∙h and 212.3W∙h). Thus, biodiesel production using low power ultrasound in the MHz frequency range is a promising technology that could contribute to biodiesel production processes.

[Determination of nickel in urine by ultrasonic-assisted ionic liquid microextraction-graphite furnace atomic absorption spectrometry]

Objective: To set up a new method to determine the nickel of urine in urine using dispersive liquid-liquid microextraction (DLLME) coupled with graphite furnace atomic absorption spectrometry (GFAAS) . Methods: From September 2018 to September 2019, the methanol, pyrrolidine dithiocarbamate and ionic liquid 1-hexyl-3-methyl-imidazolium hexafluorophosphate were used as dispersive solvent, the chelating agent and extraction solvent for the preconcentration of nickel, respectively. After adding into buffer solution of pH 9, ultrasonic dissolving for 10 minutes, centrifugal separation and then discarding the supernatant, the precipitate was saved. Dissolving the precipitate by methanol, mixing thoroughly on a vortex mixer, the 15 μl of the mixed solution was used for determination by graphite furnace atomic absorption spectrometry. Results: The linear correlation coefficient of urine nickel concentration in the range of 2.0-10.0 μg/L, r=0.999, with the detection limitation of 0.43 μg/L. The recovery rate and the relative standard deviations were 95.6%-103.7% and 2.53%-4.82%, respectively. Conclusion: The method, which has low detection limit, high recovery rate and good precision, is suitable for the determination of nickel in urine for the occupational populations exposure to nickel and non-occupational exposure.

Ultrasound assisted surface micro-dissolution to embed nano TiO2 on cotton fabrics in ZnCl2 aqueous solution

In this paper, a simple and environment friendly approach was used to prepare the multifunctional composite fabrics via coating commercial TiO₂ nanoparticles (NPs) on the surface of cotton fibers by surface micro-dissolution process in 55%wt ZnCl₂ aqueous solution under the aid of ultrasound without any adhesive. The TiO₂/cotton composite fabrics were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and thermal gravity (TG) methods. The treated fabric had photocatalytic property in Rhodamine B (RhB) degradation, and had good antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) cultures. The results of contamination degradation and antibacterial experiments confirmed that ultrasonic vibration had a significant effect on the tightly coating of nanoparticles on cotton fiber surface in the process of micro-dissolution. Even after intense ultrasonic washing, the contamination degradation rate and antibacterial efficiency of S3 (with ultrasonic) still reach 95% and 99% respectively, while S4 (without ultrasonic) only remained 72% and 59% of S2, which was attributed that ultrasonic facilitated the entry and load of nanoparticles onto the fabrics. The mechanical property of treated cotton fabrics kept well.

Fabrication of magnetic Fe3O4@nSiO2@mSiO2-NH2 core-shell mesoporous nanocomposite and its application for highly efficient ultrasound assisted dispersive µSPE-spectrofluorimetric detection of ofloxacin in urine and plasma samples

In this research, a sensitive, simple and rapid ultrasound assisted dispersive micro solid-phase extraction (USAD-µSPE) was developed using a synthesized core-shell magnetic mesoporous nanocomposite (Fe₃O₄@nSiO₂@mSiO₂-NH₂) as an efficient adsorbent for the preconcentration and spectrofluorometric determination of ofloxacin (OFL) in biological samples. The synthesized adsorbent was characterized using FT-IR spectroscopy, transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), energy dispersive X-ray (EDX) spectroscopy, thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET) analysis. The application of this magnetic nanocomposite as a sensitive solid phase for removal, preconcentration and spectrofluorometric quantification of trace amount of OFL was developed. Influence of various variables including pH, sorbent dosage, desorption solvent properties and sonication time on present method response was studied and optimized. The results showed that using the proposed method OFL can be determined in the linear concentration range of 1.0-500.0µgL^-1 with a limit of detection as low as 0.21µgL^-1 and relative standard deviation less than 2.5 (%). The results of human urine and blood plasma analysis showed that the method is a good candidate for biological sample analysis purposes.

Ultrasound assisted extraction of Maxilon Red GRL dye from water samples using cobalt ferrite nanoparticles loaded on activated carbon as sorbent: Optimization and modeling

In this research, a selective, simple and rapid ultrasound assisted dispersive solid-phase micro-microextraction (UA-DSPME) was developed using cobalt ferrite nanoparticles loaded on activated carbon (CoFe₂O₄-NPs-AC) as an efficient sorbent for the preconcentration and determination of Maxilon Red GRL (MR-GRL) dye. The properties of sorbent are characterized by X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Vibrating sample magnetometers (VSM), Fourier transform infrared spectroscopy (FTIR), Particle size distribution (PSD) and Scanning Electron Microscope (SEM) techniques. The factors affecting on the determination of MR-GRL dye were investigated and optimized by central composite design (CCD) and artificial neural networks based on genetic algorithm (ANN-GA). CCD and ANN-GA were used for optimization. Using ANN-GA, optimum conditions were set at 6.70, 1.2mg, 5.5min and 174μL for pH, sorbent amount, sonication time and volume of eluent, respectively. Under the optimized conditions obtained from ANN-GA, the method exhibited a linear dynamic range of 30-3000ngmL^-1 with a detection limit of 5.70ngmL^-1. The preconcentration factor and enrichment factor were 57.47 and 93.54, respectively with relative standard deviations (RSDs) less than 4.0% (N=6). The interference effect of some ions and dyes was also investigated and the results show a good selectivity for this method. Finally, the method was successfully applied to the preconcentration and determination of Maxilon Red GRL in water and wastewater samples.

Ultrasound assisted combined molecularly imprinted polymer for selective extraction of nicotinamide in human urine and milk samples: Spectrophotometric determination and optimization study

Ultrasound-assisted dispersive solid phase microextraction followed by UV-vis spectrophotometer (UA-DSPME-UV-vis) was designed for extraction and preconcentration of nicotinamide (vitamin B₃) by HKUST-1 metal organic framework (MOF) based molecularly imprinted polymer (MIP). This new material was characterized by FTIR and FE-SEM techniques. The preliminary Plackett-Burman design was used for screening and subsequently the central composite design justifies significant terms and possible construction of mathematical equation which give the individual and cooperative contribution of variables like HKUST-1-MOF-NA-MIP mass, sonication time, temperature, eluent volume, pH and vortex time. Accordingly the optimum condition was set as: 2.0mg HKUST-1-MOF-NA-MIP, 200μL eluent and 5.0min sonication time in center points other variables were determined as the best conditions to reach the maximum recovery of the analyte. The UA-DSPME-UV-vis method performances like excellent linearity (LR), limits of detection (LOD), limits of quantification of 10-5000μgL^-1 with R² of 0.99, LOD (1.96ngmL^-1), LOQ (6.53μgL^-1), respectively show successful and accurate applicability of the present method for monitoring analytes with within- and between-day precision of 0.96-3.38%. The average absolute recoveries of the nicotinamide extracted from the urine, milk and water samples were 95.85-101.27%.

Blind percutaneous liver biopsy in infants and children: Comparison of safety and efficacy of percussion technique and ultrasound assisted technique

BACKGROUND AND STUDY AIMS

Liver biopsy remains the most reliable method to diagnose various hepatic disorders in children. We aimed to assess the technical success and complication rate of ultrasound (US) assisted percutaneous liver biopsy versus transthoracic percussion guided technique in paediatrics.

PATIENTS AND METHODS

This randomized controlled study included all cases performing liver biopsy at Paediatric Hepatology Unit, Cairo University Paediatric Hospital over 12months.

RESULTS

Patients were 102 cases; 62 were males, with age range 18days to 12years. Fifty seven procedures were done using the percussion guided technique and 45 cases were US assisted. The total number of complicated biopsies was 14 (13.7%), with more serious complications occurring in the percussion group. Complications were more frequent with younger age, lower platelet count, number of passes and occurrence of hypotension.

CONCLUSION

US assisted percutaneous liver biopsy, although more costly, but may be safer to perform particularly in younger age.

Ultrasound-assisted ionic liquid dispersive liquid-liquid microextraction combined with graphite furnace atomic absorption spectrometric for selenium speciation in foods and beverages

A rapid and environmentally friendly ultrasound assisted ionic liquid dispersive liquid liquid microextraction (USA-IL-DLLME) was developed for the speciation of inorganic selenium in beverages and total selenium in food samples by using graphite furnace atomic absorption spectrometry. Some analytical parameters including pH, amount of complexing agent, extraction time, volume of ionic liquid, sample volume, etc. were optimized. Matrix effects were also investigated. Enhancement factor (EF) and limit of detection (LOD) for Se(IV) were found to be 150 and 12 ng L(-1), respectively. The relative standard deviation (RSD) was found 4.2%. The accuracy of the method was confirmed with analysis of LGC 6010 Hard drinking water and NIST SRM 1573a Tomato leaves standard reference materials. Optimized method was applied to ice tea, soda and mineral water for the speciation of Se(IV) and Se(VI) and some food samples including beer, cow's milk, red wine, mixed fruit juice, date, apple, orange, grapefruit, egg and honey for the determination of total selenium.