复频聚焦超声激活血卟啉杀伤肿瘤细胞K562的实验研究

为了研究单复频超声激活血卟啉对人体肿瘤细胞的杀伤效应，利用自制的复频聚焦换能器激活血卟啉，以肿瘤细胞K562：为研究对象，采用MTF法(四唑盐比色法)检测在不同超声处理时间、不同频率、不同溶液环境下、不同孵育时间条件下，声动力学激活血卟啉法对肿瘤细胞的杀伤效应。结果表明，复频聚焦超声激活血卟啉对肿瘤细胞具有较强的杀伤效应，是一种有应用前景的治疗肿瘤的新技术。     

用碘释放法研究低频超声的声化学产额

本文用碘释放法研究了２８ｋＨｚ超声的声化学产额随扬强和辐照时间的变化。表明声化学产额随声强呈非线性变化，而随辐照时间近似呈线性变化。进而研究了由２８ｋＨｚ与１．０６ＭＨｚ组成的正交辐照系统的声化学产额。     

Enhanced heat deposition using ultrasound contrast agent--modeling and experimental observations

Ultrasound contrast agents (UCA), created originally for visualization and diagnostic purposes, recently have been suggested as efficient enhancers of ultrasonic power deposition in tissue. The ultrasonic energy absorption by the contrast agents, considered as problematic in diagnostic imaging, might have beneficial impact in therapeutic applications such as targeted hyperthermia-based or ablation treatments. Introduction of gas microbubbles into the tissue to be treated can improve the effectiveness of current treatments by limiting the temperature rise to the treated site and minimizing the damage to the surrounding healthy tissues. To this end, proper assessment of the governing parameters of energy absorption by ultrasonically induced stabilized bubbles is important for both diagnostic and therapeutic ultrasound applications. The current study was designed to predict theoretically and measure experimentally the dissipation and heating effects of encapsulated UCA in a well-controlled and calibrated environment. The ultrasonic effects of the microbubble concentration, transmitted intensity, and frequency on power dissipation and stability of the UCA have been studied. The maximal temperature elevation obtained during 300 s experiments was 21 degrees C, in a 10 ml volume target containing UCA, insonifled by unfocused 3.2 MHz continuous wave (CW) at spatial average intensity of 1.1 W/cm2 (182 kPa). The results also suggest that higher frequencies are more efficiently absorbed by commonly used UCA. In particular, for spatial average intensity of 1.1 W/cm2 and concentration of 5 x 10(6) microspheres/cm3, no significant reduction of UCA absorption was noticed during the first 150 s for insonation at 3.2 MHz and the first 100 s for insonation at 1 MHz. In addition, when lower average intensity of 0.5 W/cm2 (160 kPa) at 3.2 MHz was used, the UCA absorptivity sustained for almost 200 s. Thus, when properly activated, UCA may be suitable for localized hyperthermic therapies.     

Water-cooled, high-intensity ultrasound surgical applicators with frequency tracking

High-intensity, focused ultrasound (HIFU) applicators have been developed for arresting bleeding with the ultimate intent of use in surgery. The design uses a tapered titanium component for transmission coupling of the ultrasound energy from a spherically curved transducer to biological tissues. The nominal operating frequency is 5.5 MHz, in a highly resonant mode (quality factor of 327 with water load). Liquid cooling is used to remove energy loss-important at net applied power greater than 18 W/cm/sup 2/ at the surface of the piezoelectric element. A downward resonance frequency shift (>20 kHz) occurs, even with cooling, as the applicator warms with normal operation. A feedback technique is used for maintaining the excitation near optimum resonance. Standing wave ratios of the applied power of 1.6 or less are thus sustained. The system and applicators have been found to be highly robust, effective in achieving hemostasis in the hemorrhaging liver, spleen, lung, or blood vessels in rabbit and pig experiments. One unit has been operated for over 1.7 hours in treating organ hemorrhage in blunt trauma experiments with nine swine with electrical net power of up to 158 W (31 W/cm/sup 2/ across the transducer) and intensity of 2560 W/cm/sup 2/ at focus.     

Ultrasonic attenuation in human calcaneus from 0.2 to 1.7 MHz

Ultrasonic attenuation has been demonstrated to be a useful measurement in the diagnosis of osteoporosis. Most studies have employed ultrasound in a range of frequencies from about 200 kHz-300 kHz to 600 kHz-1 MHz, and many have assumed a linear dependence of attenuation on frequency. In order to investigate the attenuation properties of human calcaneus at higher frequencies, 16 defatted human calcanea were interrogated in vitro using two matched pairs of transducers with center frequencies of 500 kHz and 2.25 MHz. The linear dependence of attenuation on frequency seems to extend up to at least 1.7 MHz. The correlation between attenuation coefficient and frequency from 400 kHz to 1.7 MHz was r = 0.999 (95% confidence interval, CI, = 0.998-1.00). The measurements suggest that some deviations from linear frequency dependence of attenuation may occur at lower frequencies (below 400 kHz), however.     

常温下超声辅助合成乙酸正己酯的影响因素

以乙酸、正己醇为原料,浓硫酸为催化剂,在常温下用超声合成了乙酸正己酯。实验针对有无超声、超声频率、超声声强、温度、催化剂用量等参数对催化合成乙酸正己酯的影响。得到30℃下的优化工艺条件为：声频10 kHz,声强1.0 W/cm2,催化剂用量1.0%（v/v）。实验结果表明,超声在常温下辅助合成乙酸正己酯有很好的效果,酯化率能达到50%以上。该方法具有反应条件温和、操作简单且反应速度很快等优点。     

超声波强化庞庄煤制浆的试验研究

使用自制的新型萘油添加剂对庞庄煤制浆,考察了超声作用前后煤浆中煤粉粒度分布与添加剂在煤粒表面吸附能力的变化及其对水煤浆性能的影响。煤浆经超声作用后,浆体中细级煤粒的含量与煤粒对萘油添加剂的平衡吸附量都增加,煤浆稳定性显著提高。在超声发射强度为60W/cm2,频率为20kHz,萘油添加剂加入量为1%的条件下,超声辐照时间小于3min时煤浆粘度降低,辐照时间超过3min,煤浆粘度反而升高。当添加剂加入量为2%时,浆体粘度在试验超声作用时间内一直降低。     

双频复合超声强化无水葡萄糖溶液结晶成核研究

溶液结晶技术在许多领域有着广泛的应用,其中结晶成核是溶液结晶的关键环节。以无水α-葡萄糖为研究对象,采用双频复合超声(25 k Hz+40 k Hz)强化糖液结晶成核,研究了溶液浓度、超声功率和作用时间对成核速率的影响,对单频和双频作用的晶核形态进行了对比,并采用碘化钾溶液中碘的释放量研究超声空化产额。研究结果表明:在同等条件下,双频复合超声降低了溶液成核的初始浓度,提高了成核速率,同时得到粒度均匀的晶核;双频复合超声的空化产额远高于单频25 k Hz超声和单频40 k Hz超声的空化产额,双频复合超声具有协同作用。双频复合超声强化溶液成核是一种快速、高效、节能的方法。     

Superthreshold behavior and threshold estimates ofultrasound-induced lung hemorrhage in adult rats: role of beamwidth

It is well documented that ultrasound-induced lung hemorrhage can occur in mice, rats, rabbits, pigs, and monkeys. The objective of this study was to assess the role of the ultrasound beamwidth (beam diameter incident on the lung surface) on lesion threshold and size. A total of 144 rats were randomly exposed to pulsed ultrasound at three exposure levels and four beamwidths (12 rats per group). The three in situ peak rarefactional pressures were about 5, 7.5, and 10 MPa. The four 19-mm-diameter focused transducers had measured pulse-echo -6-dB focal beamwidths of 470 μm (2.8 MHz; f/1), 930 μm (2.8 MHz; f/2), 310 μm (5.6 MHz; f/1), and 510 μm (5.6 MHz; f/2). Exposure durations were 10 s, pulse repetition frequencies were 1 kHz, and pulse durations were 1.3 μs (2.8 MHz; f/1), 1.2 μs (2.8 MHz; f/2), 0.8 μs (5.6 MHz; f/1) and 1.1 μs (5.6 MHz; f/2). The lesion surface area and depth were measured for each rat as well as the percentage of rats with lesions per group. Logistic regression analysis and Gaussian-Tobit analysis methods were used to analyze the data. The effects of in situ peak rarefactional pressure and beamwidth were highly significant, but ultrasonic frequency was not significant. In addition, the estimated interaction between in situ peak rarefactional pressure and beamwidth was positive and highly significant. The ultrasound beamwidth incident on the lung surface was shown to strongly affect the percentage and size of ultrasound-induced lung hemorrhage lesions. Even though ultrasonic frequency was an experimental variable, it was not shown to affect the lesion percentage or size     

声化学激活血卟啉对瘤细胞K562作用的研究

文章研究了超声激活血卟啉对人体肿瘤细胞K562的作用以及声辐照剂量和血卟啉浓度对瘤细胞杀伤率的影响。结果表明，声辐射剂量和血卟啉浓度和瘤细胞杀伤率呈正相关系。当频率为1．8MHz、声强度为1．5W／cm^2、作用时间为60s、血卟啉浓度为200μg／mL时，超声激活血卟啉对K562肿瘤作用效果较佳，杀伤率达98％，超声单独作用仅为42％，单纯血卟啉无抗肿瘤效应。     

Sonochemical disinfection of municipal wastewater

The application of high intensity, low frequency ultrasound for the disinfection of simulated and septic tank wastewaters is evaluated in this work. Laboratory scale experiments were conducted at 24 and 80kHz ultrasound frequency with horn-type sonicators capable of operating in continuous and pulsed irradiation modes at nominal ultrasound intensities up to 450W. For the experiments with simulated wastewaters, Escherichia coli were used as biological indicator of disinfection efficiency, while for the experiments with septic tank wastewaters, the total microbiological load was used. Complete elimination of E. coli could be achieved within 20-30min of irradiation at 24kHz and 450W with the efficiency decreasing with decreasing intensity and frequency. Moreover, continuous irradiation was more effective than intermittent treatment based on a common energy input. Irradiation of the septic tank effluent prior to biological treatment at 24kHz and 450W for 30min resulted in a three-log total microbiological load reduction, and this was nearly equal to the reduction that could be achieved during biological treatment. Bacterial cell elimination upon irradiation was irreversible as no reappearance of the microorganisms occurred after 24h.     

Effects of contrast agent infusion rates on thresholds for tissue damage produced by single exposures of high-intensity ultrasound

Stabilized microbubble ultrasound contrast agents (UCA) have potential to aid tissue ablation during ultrasound surgery by enhancing both cavitational and thermal damage mechanisms. Previously, we showed UCA infused at a rate of 1 microL/kg/min prior to ultrasound exposure could reduce the total energy required to produce tissue damage by up to two orders of magnitude. In this paper, we evaluate thresholds for macroscopic tissue damage with UCA infusion rates (IR) of 0.1, 0.3, 1, 3, and 10 microL/kg/min to determine IR potentially effective for ultrasound therapy. Canine kidneys were surgically externalized and insonified with single exposures of focused ultrasound. Incident exposures were 1.44 MHz tone bursts, either 250 ms in duration with intensity between 500 W/cm2 and 3200 W/cm2, or 100 micros to 1 s in duration with intensity equal to 3200 W/cm2. Probabilities of tissue damage occurrence were determined for each set of exposure conditions (intensity, duration, and IR). A threshold intensity and threshold duration, defined as the quantities for which tissue damage occurred with probability equal to 0.5, were estimated for each IR. Results show that, as IR increased from 0.1 to 10 microL/kg/min, the threshold intensity decreased by up to a factor of 3, and threshold duration decreased by up to a factor of 200. Microbubble introduction at IR up to 10 microL/kg/min thus may be effective in aiding ultrasound therapy.     

超声对黑曲霉产菊粉酶的影响

为了探索超声提高黑曲霉产菊粉酶的可能,考察了超声处理时间、超声频率和不同发酵时期超声处理等参数的影响。试验发现在黑曲霉的延滞期和对数增长期的初期阶段（〈30h）,40kHz和59kHz的超声处理均抑制了黑曲霉产菊粉酶的活力,高频超声的抑制效果更明显,菊粉酶活力降低了47.4%。在黑曲霉的对数增长期的后期阶段（〉36h）,这两种频率的超声处理均促进了黑曲霉产菊粉酶的活力,低频超声的促进作用更明显,菊粉酶活力提高了29.3%。结果表明,在一定条件下,超声能够促进微生物的发酵产酶。     

Case study of the sonochemical decolouration of textile azo dye Reactive Black 5

The decolouration and mineralization of reactive dye C.I. Reactive Black 5, a well-known representative of non-biodegradable azo dyes, by means of ultrasonic irradiation at 20, 279 and 817kHz has been investigated with emphasis on the effect of various parameters on decolouration and degradation efficiency. Characterization of the used ultrasound systems was performed using calorimetric measurements and oxidative species monitoring using Fricke and iodine dosimeter. Experiments were carried out with low frequency probe type, and a high-frequency plate type transducer at 50, 100 and 150W of acoustic power and within the 5-300mg/L initial dye concentration range. Decolouration, as well as radical production, increased with increasing frequency, acoustic power, and irradiation time. Any increase in initial dye concentration results in decreased decolouration rates. Sonochemical decolouration was substantially depressed by the addition of 2-methyl-2-propanol as a radical scavenger, which suggests radical-induced reactions in the solution. Acute toxicity to marine bacteria Vibrio fischeri was tested before and after ultrasound irradiation. Under the conditions employed in this study, no toxic compounds were detected after 6h of irradiation. Mineralization of the dye was followed by TOC measurements. Relatively low degradation efficiency (50% after 6h of treatment) indicates that ultrasound is rather inefficient in overall degradation, when used alone.     

Ultrasonic Plasma Spray--A New Plasma Spray Process

The method of arc- ultrasonic is introduced into plasma spray process. The process of spray ZrO2-NiCoCr AlY thermal barrier coatings (TBCs) using air plasma spray (APS) process is studied. A exciting source which can be adjusted from audio frequency to several hundred thousand Hertz is designed successfully. The ultrasonic exciting source is coupled with conventional DC spraying power supply. A few ultrasonic frequencies are selected in the testing. Several parts of the coatings with the coupling arc- ultrasonic are compared with the coatings without it. The results show: with 50 kHz and 80 kHz ultrasound, the coating qualities are improved, whereas 30 kHz has an opposite effect.     

A multifunctional nanoparticle system combines sonodynamic therapy and chemotherapy to treat hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common and deadly malignancies worldwide.To date,the survival of patients with HCC has not improved because of the insensitivity of HCC to conventional treatments.Sonodynamic therapy (SDT) is a promising new approach that shows remarkable potential in the treatment of HCC.Here,we designed a simple,biocompatible,and multifunctional nanosystem that combines SDT and chemotherapy to treat HCC.This nanosystem,called HPDF nanoparticles,had a core-shell structure in which hematoporphyrin (HP) was complexed with doxorubicin (DOX) to form the hydrophobic core and the surface was coated with Pluronic F68 to form the hydrophilic shell.In HCC cells,HPDF nanoparticles in combination with ultrasonic irradiation (1.0 MHz,1.5 W/cm2,30 s) exhibited potent cytotoxicity,resulting from the synergistic effects of a large amount of reactive oxygen species generated from HP and DOX-induced DNA damage.Notably,HPDF nanoparticles in combination with ultrasonic irradiation significantly reversed drug resistance in Nanog-positive cancer stem cells (CSCs) in HCC.In nude mice bearing HCC tumors,HPDF nanoparticles efficiently accumulated in the tumors and reached the maximum levels within 6-8 h,post intravenous injection.HPDF nanoparticles,in combination with ultrasonic irradiation (1.0 MHz,3 W/cm2,5 min),suppressed tumor growth,angiogenesis,and collagen deposition,considerably.In summary,our results show that HPDF nanoparticles can effectively combine SDT and chemotherapy to inhibit HCC growth and progression through multiple mechanisms in both cellular and animal models.     

低强度超声波辐照引发MMA的本体聚合

利用功率密度仅有0.25 W/cm2的超声波为辐射源对溶有聚甲基丙烯酸甲酯(PMMA)的MMA物料体系进行辐照引发了MMA的本体聚合。考察了超声波、促进剂、阻聚剂、反应气氛等因素对聚合反应的影响,利用凝胶色谱仪对产物分子量及分布进行了表征。结果表明,该反应为自由基引发聚合,大分子与单体之间的摩擦力是产生自由基的根本原因;超声波频率、辐照时间等对聚合速率有明显影响;产物具有较为规整的分子量分布且几乎不含引发剂残基,可应用于对材料纯度有特殊要求的领域。     

Catalysis of advanced oxidation reactions by ultrasound: a case study with phenol

The present study is about the enhancement in ozone-mediated degradation and UV (254nm) photolysis of phenol in aqueous solutions by 300kHz acustic cavitation and the selection of operating parameters for optimum phenol removal efficiency. The method was based on monitoring of the concentration of phenol during 90min exposure to ozonation, sonication, UV photolysis, O(3)/ultrasound, UV/ultrasound and O(3)/UV/ultrasound operations. It was found that ozonation at alkaline pH was an effective method of phenol destruction, but it was considerably more effective when applied simultaneously with ultrasonic irradiation. The observed synergy particularly at alkaline pH was attributed to combined effects of: (i) increased ozone mass transfer (upon hydrodynamic shear forces created by ultrasonic bubbles) and (ii) excess hydroxyl radical formation (upon thermal decomposition of ozone in the gaseous cavity bubbles). Degradation of phenol by photolysis alone was negligible, while combination of UV-irradiation and ultrasound rendered considerable degrees of decay. The synergy here was explained by excess hydroxyl radicals that are formed by photolysis of ultrasound-generated H(2)O(2). Maximum rate of phenol degradation was observed in case of combined application of ozone, UV and ultrasound at basic pH.     

Chromatic aberration of an air-coupled ultrasonic Fresnel zone-plate

A micromachined Fresnel zone-plate has been used to focus ultrasonic waves in air over a range of frequencies (450 to 900 kHz). The zone-plate was mounted upon a planar micromachined air-coupled capacitance transducer, which was capable of generating toneburst ultrasonic waves in air over a wide frequency bandwidth (<100 kHz to 2 MHz). A second air-coupled capacitance detector (apertured to 200 mum) was scanned in the field of the zone-plate source in order to image the generated ultrasonic field at various frequencies of operation. It was found that the ~680 mum spot size of the experimental zone-plate did not vary appreciably with changing frequency, whereas the focal length increased markedly with increasing frequency (from ~5 mm at 450 kHz up to ~15 mm at 900 kHz). These findings are shown to be in excellent agreement with previously reported theoretical predictions by the authors.     

Circular acoustogyration effect on gold nanoparticles grown on indium tin oxide

Gold nanoparticles deposited on indium-tin-oxide coated substrates show substantial circularly polarized acoustically induced light gyration (AILG) at liquid-helium temperature. The effect was observed only during simultaneous treatment by two coherent acoustic waves with basic frequencies of 0.8-1.6 MHz and corresponding coherent double-frequency acoustical components. It was found that increasing the basic acoustical frequency to 1.6 MHz led to suppression of the effect. ATi:sapphire laser with a pulse duration of approximately 80 fs allowed us to achieve the maximal value for the AILG. Enhancement of the pulse duration higher than 200 fs also substantially diminished the effect. The maximally achieved value of the AILG susceptibility (described by a fourth-order axial tensor) caused by the circularly polarized acoustical probe field at an acoustical power density of approximately 3 W/cm2 at T = 4.2 K was equal to approximately 7.8 deg/mm for the circular acoustical wave polarization. The maximal AILG coefficient is achieved for samples that possess minimal resistivity. The investigated composites possess an acoustically induced helicoidal grating that disappeared 20 s after switching off the acoustical fields.