基于边缘检测的图像分割的超声诊断机器人控制系统设计

传统系统在嵌入信息后峰值信噪比较高,使图像分割结果与实际效果相差较大,导致控制系统超声诊断结果并不精准,针对该问题,提出基于边缘检测的图像分割的超声诊断机器人控制系统设计。在控制系统的硬件结构部分,以STM32F103C8T6单片机为核心的控制器,使用型号为3MC58的步进电机驱动器,通过角位移量控制脉冲个数,以实现更加准确的定位。在软件设计中,通过图像分割技术检测图像边缘特征,提高图像分割精度和准确度,帮助诊断机器人提高诊断功能。分析不同嵌入率下峰值信噪比,在确定该值后将传统系统与该系统的超声诊断功能对比分析,由实验结果可知,该系统在嵌入信息后峰值信噪比较高的情况下也能保证图像分割结果与实际效果一致,对0.8 bpp嵌入率图像的分割处理效果平均值为89%,超声诊断准确率平均值为88.6%,表明该系统的控制性能较好,能够为医学、航天航空及军事领域提供设备支持。     

Assisted extraction of rosemary antioxidants with green solvents

The use of natural antioxidants in the food industry has increased in the last years and there is a growing interest in improving the extraction processes using GRAS (general recognize as safe) solvents. In this work the extraction of antioxidants from rosemary with ethanol and water as solvents has been studied using different extraction processes (conventional, microwave assisted - MAE - and ultrasound assisted - USAE -) and plant pretreatments (deoiled and milled, deoiled and fresh plant). Total phenolic compounds in the extracts were determined by the Folin-Ciocalteu assay and HPLC with UV detection was employed for the quantitation of the main antioxidant compounds: rosmarinic acid and carnosic acid. The antioxidant activity of the extract was determined by the DPPH scavenging assay. The double pretreatment, deoiling by solvent free microwave extraction (SFME) and milling, has shown to be essential to overcome inner mass transfer limitations. Extraction efficiency can be additionally enhanced by microwave and ultrasound assisted extraction process, being this latter more significant in aqueous extracts.     

超声技术在食品工业中的应用研究进展

超声波是频率超过20 k Hz的声波,其声场具有独特的空化现象,可同时产生热效应和机械效应,在食品加工领域应用具有处理效率高、可控性好、成本低等优点,近年来在食品加工领域被广泛关注。本文从超声技术作用机制出发,综述了国内外有关超声技术在食品加工业中的应用和研究新进展,主要包括利用高频和低频超声对不同食品原料进行超声提取、超声降解、超声辅助酶解、超声干燥、超声灭菌、超声乳化和超声嫩化等方面,并对其可能的作用机制进行了分析归纳。超声技术除具有传统破碎、断裂原料细胞作用之外,超声辅助酶解等生物物理结合加工方式也符合"十三五"食品科技创新专项规划中发展现代食品绿色加工与低碳制造技术的要求。本文为食品绿色制造和产业转型升级提供了理论依据。     

Application of power ultrasound on the convective drying of fruits and vegetables: effects on quality

Drying gives rise to products with a long shelf life by reducing the water activity to a level that is sufficiently low to inhibit the growth of microorganisms, enzymatic reactions and other deteriorative reactions. Despite the benefits of this operation, the quality of heat sensitive products is diminished when high temperatures are used. The use of low drying temperatures reduces the heat damage but, because of a longer drying time, oxidation reactions occur and a reduction of the quality is also observed. Thus, drying is a method that lends itself to being intensified. For this reason, alternative techniques are being studied. Power ultrasound is considered as an emerging and promising technology in the food industry. The potential of this technology relies on its ability to accelerate the mass transfer processes in solid–liquid and solid–gas systems. Intensification of the drying process with power ultrasound can be achieved by modifying the product behavior during drying, using pre‐treatments such as soaking in a liquid medium assisted acoustically or, during the drying process itself, by applying power ultrasound in the gaseous medium. This review summarises the effects of the application of the power ultrasound on the quality of different dried products, such as fruits and vegetables, when the acoustic energy is intended to intensify the drying process, either when the application is performed before pretreatment or during the drying process. © 2017 Society of Chemical Industry     

Impact of nonthermal processing on different milk enzymes

Milk is highly perishable and deteriorates rapidly during storage. Although the thermal processing technologies successfully inactivate many enzymes and microorganisms up to a required level, they can negatively affect the natural flavour of dairy foods and decrease their nutritional value. Alternative nonthermal technologies have been established as an interesting approach to produce safe and healthy dairy products, without compromising their nutritional quality. These techniques have the ability to inactivate milk enzymes without affecting the milk quality. In addition, the combination of two different nonthermal techniques and mild heating has proven to be more effective to provide safety to milk when compared to the treatments alone. This review aims to evaluate the impact of nonthermal technologies, in particular, ultrasound, pulsed electric field, high‐pressure processing and ultraviolet irradiation on milk enzymes.     

Characterization of cake batters by ultrasound measurements

This work was undertaken in order to determine the feasibility of a low intensity ultrasonic sensor to be used in the control of the cake manufacturing process. A set of 27 batters with different oil, egg and sugar contents were elaborated to obtain products with different physical characteristics. The physical properties of batters (density, viscosity and rheology) and cakes (volume, symmetry, volume index, height and density) were correlated with ultrasonic measurements. Significant correlations were obtained between the acoustic impedance and the batter consistency (R² = 0.53), G″ (R² = 0.66), and G^* (R² = 0.53). The ultrasound measurement provided better correlations with physical properties of cakes than any of the conventional methods of batter measurement. This system has shown an interesting potential for industrial applications, especially in the detection of deficient batters.     

超声提取甘草色素及稳定性研究

采用超声法对新疆野生甘草色素进行提取,并对其在酸碱、金属离子等的稳定性进行了详细研究.结果表明:野生甘草色素耐热、耐光性较高,在碱性介质中可稳定存在,为甘草色素这种具有功能型性质的色素的开发、利用提供理论依据,同时为更充分地利用甘草资源提供了依据.     

Inactivation of Cronobacter sakazakii in head lettuce by using a combination of ultrasound and sodium hypochlorite

The present study investigated the synergistic effects of combined ultrasound (37 kHz, 380 W for 5–100 min) and sodium hypochlorite (NaOCl) (50–200 ppm) on reducing Cronobacter sakazakii KCTC 2949 in head lettuce. Ultrasound was not enough to inactivate C. sakazakii (0.01–0.58 log-reduction), whereas NaOCl significantly (P < 0.05) reduced C. sakazakii (0.58–2.77 log-reduction). Despite the significant reduction in C. sakazakii with NaOCl treatment (200 ppm), the combination of 100 min ultrasound and 200 ppm NaOCl resulted in an additional 1.67 log-reduction of C. sakazakii (4.44 log-reduction = 2.77 + 1.67 log). Synergistic reductions on C. sakazakii were observed in most combined treatments, although the most synergistic reduction values were <1.0 log₁₀ CFU/g. The highest synergistic value of reduction in head lettuce was 1.08 log₁₀ CFU/g when treated with a combination of 100 min ultrasound and 200 ppm NaOCl. Moreover, the pH and °Brix after combined treatment with 5–100 min ultrasound and 50–200 ppm NaOCl did not significantly differ from any single treated lettuce. These results indicate that combined treatment with 100 min ultrasound and 200 ppm NaOCl could be a potential approach to reduce C. sakazakii on post-harvest leaf vegetable during processing and enhance the shelf-life during distribution and storage.     

A new approach for measuring the trabecular bone density through the echosound backscattering: An ex vivo validation on human femoral heads

The aim of this paper was to propose a novel approach to the ultrasound (US) characterization of human bones through an improved measurement of the apparent integrated backscatter (AIB). Four intact human femoral heads were studied ex vivo in their physiologic morphological configuration, including cartilaginous, cortical and trabecular regions. Each sample underwent an US acquisition performed with a clinically-available echographic device and a micro-computed tomography (micro-CT) scan, whose spatial resolution was preliminarily optimized for this specific purpose. A dedicated US signal compensation was employed in the AIB computation, to take into account the variability of sample-probe distance and cortical bone thickness. Obtained results showed an appreciable global correlation between AIB and the trabecular bone volume fraction as quantified by the micro-CT parameter BV/TV (|r| = 0.69). The proposed approach has interesting perspectives for a clinical translation as an innovative method for in vivo US measurement of proximal femur bone density.