Acoustic levitation method (ALM) is a container-less processing method with applications in various fields, including material processing, biology, and analytical chemistry. Because it is a ...container-less processing technique, ALM could prevent nucleation and contamination of materials being processed via contact with a container wall. It is well-known that evaporation of a sample is an important process in container-less processing of materials; however, the mechanism of evaporation in multicomponent droplets in a single acoustic levitator is still unclear. Thus, we evaluate and understand the evaporation of an acoustically levitated multicomponent droplet and manipulate the evaporation process of the sample in this study. Specifically, we investigate the evaporation process of pure and multicomponent droplets using container-less processing experimentally. The evaporation processes and temporal evolution of the surface temperature of a multicomponent droplet were evaluated using a high-speed camera and radiation thermometer, respectively. We used water, ethanol, methanol, hexane, acetone, pentane, and binary solutions (solution of 25 wt%, 50 wt%, and 75 wt% ethanol, methanol, and acetone, respectively) as test samples to study the effect of saturated vapor pressure on evaporation. Ethanol, methanol, and acetone droplets evaporate in two different stages. It was observed that the water vapor in the air condensed during the evaporation process of these water-soluble droplets; hence, our experimental data did not agree with the theoretical prediction in accordance with the d2 law. Nevertheless, the evaporation behavior in the first stage of evaporation was consistent with the theoretical prediction. Furthermore, for binary droplets, as the concentration of the resultant solution increased owing to evaporation, the transition time from the first to the second stage of evaporation also increased. Based on these observations, estimation equations for binary droplets were developed to ensure that the experimental and theoretical values were in good agreement.
The acoustic levitation method (ALM) is expected to be applied as a container-less processing technology in the material science, analytical chemistry, biomedical technology, and food science domains ...because this method can be used to levitate any sample in mid-air and prevent nucleation and contamination due to the container wall. However, this approach can lead to nonlinear behavior, such as acoustic streaming, which promotes the evaporation of a levitated droplet. This study aims to understand the evaporation and precipitation kinetics of an acoustically levitated multicomponent droplet. An experimental investigation of the evaporation process of a salt solution droplet was performed, and the experimental results were compared with those of the
-law. The droplet was noted to evaporate in two stages owing to the precipitation of the salt. Because of the vapor pressure depression, the experimental data did not agree with the classical prediction obtained using the
-law. However, the experimental results were in partial agreement with those of the
-law when the vapor pressure depression was considered by using the concentration estimate at each time, as obtained from the experimental results. In addition, it was observed that the time when the salt completely precipitated could be estimated by using the extended theory. These findings provide physical and practical insights into the droplet evaporation mid-air for potential lab-in-a-drop applications.
The development of contactless sample manipulation for microfluidic purposes has attracted significant attention within the physicochemical fields. Most existing studies focus on the interactions of ...unheated liquid substrates and on heated/unheated solid substrates. Therefore, the dynamics of droplets on heated liquid pools have yet to be explored. Here, we present an experimental investigation on the levitated and self-propelled droplets on a heated pool. We aim to identify the effect of the pool temperature and the thermophysical properties of droplets on the dynamics of a self-propelled Leidenfrost droplet on a heated pool. The motion of droplets after levitation on the heated pool is visualized. To elucidate the self-propulsion of Leidenfrost droplets, we quantify the thickness of the vapour film between the approaching droplet and the pool surface. Our experimental results show a quantitative agreement with the simple model prediction for self-propelled Leidenfrost droplets. Our results provide deeper physical insights into the dynamics of Leidenfrost droplets on a heated pool for contactless and contamination-free sample manipulation.
Acoustic manipulation by an ultrasonic phased array provides an entirely new approach to processes such as coalescence, mixing, separation, and evaporation occurring in the generation of new ...materials, physical property measurement, the biomedical industry, etc. However, to date, ultrasonic phased arrays have not been fully investigated for applications in fluid manipulation. This paper provides contactless coalescence and mixing techniques for droplets in air by controlling the acoustic potential by using an ultrasonic phased array. We focused on mode oscillation to propose an efficient mixing technique for liquid without contact. A comparison of mixing performance between cases with mode oscillation and without mode oscillation showed that the flow induced by mode oscillation promotes droplet mixing. Our paper demonstrates the feasibility of contactless coalescence and mixing as a first step in fluid manipulation with a phased array.
Background:The current status and outcomes of direct oral anticoagulant (DOAC) use have not been widely evaluated in unselected patients with atrial fibrillation (AF) in the real world.Methods and ...Results:The Fushimi AF Registry is a community-based prospective survey of AF patients who visited the participating medical institutions (n=80) in Fushimi, Kyoto, Japan. Follow-up data with oral anticoagulant (OAC) status were available for 3,731 patients by the end of November 2015. We evaluated OAC status and clinical outcomes according to OAC status. The number (incidence rate) of stroke/systemic embolism (SE) and major bleeding events during the median follow-up of 3.0 years was 224 (2.3%/year) and 177 (1.8%/year), respectively. After the release of DOAC, the prevalence of DOAC use increased gradually and steadily, and that of warfarin, DOAC and no OAC was 37%, 26% and 36%, respectively in 2015. On Cox proportional hazards modeling incorporating change in OAC status as a time-dependent covariate for stroke/SE and major bleeding events, use of DOAC compared with warfarin was not associated with stroke/SE events (HR, 0.95; 95% CI: 0.59–1.51, P=0.82) or major bleeding events (HR, 0.82; 95% CI: 0.50–1.36, P=0.45).Conclusions:In real-world clinical practice, there were no significant differences in stroke/SE events or major bleeding events for DOAC compared with warfarin in patients with AF.
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This paper compares batch and continuous technologies in terms of product quality and process performance in pharmaceutical tablet manufacturing using ethenzamide as the active ...pharmaceutical ingredient. Batch and continuous processes using wet granulation were investigated by performing experiments on the scale of 5 and up to 100 kg/lot, using the same raw materials. Three technologies were tested and compared: (i) batch technology using fluidized bed granulation, (ii) batch technology using high shear granulation, (iii) continuous technology using high shear granulation. In the full-scale experiment, in all three technologies including continuous technology, the quality of the tablets fulfilled the target values regarding hardness, active pharmaceutical ingredient content, and dissolution. The granules produced by different technologies, however, presented varying attributes regarding granule size distribution, loose bulk density, or scanning electron microscope images. The process performance, more specifically the yield, was slightly better for batch technologies than for the continuous technology, mainly due to losses in the start-up operation. Notably, this study has shown that continuous technology, which is generally believed to not entail scale-up procedures, could in fact, require parameter adjustment for prolonged operation. The results provided suggestions for improvements to implement large-scale continuous technologies in the pharmaceutical industry.
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This paper aims to determine key parameters that affect tablet quality and productivity in continuous tablet manufacturing. Experiments were performed based on design of experiments ...using a continuous high-shear granulator and ethenzamide as the active pharmaceutical ingredient. To guide a systematic and comprehensive parameter analysis, a parameter framework was defined that comprised five input parameters on raw material properties and process parameters, 11 intermediate parameters on granule properties, and 11 output parameters on tablet quality and productivity. The interrelationships were analyzed statistically and were described as matrix functions. The liquid/solid ratio was the key parameter that affected circularity, density, and flowability as the granule properties, and disintegration and dissolution as the tablet quality. The maximum acceptable manufacturing rate that governs productivity was also affected by the liquid/solid ratio. Circularity was found to affect disintegration and dissolution. This result was specific to the setup of the study, but suggested development opportunities for a new process analytical technology system/quality-by-design application based on circularity. In addition, practical findings were obtained as follows: (1) high-speed manufacturing favored a lower liquid/solid ratio, and (2) high circularity slowed down disintegration/dissolution. This obtained knowledge will enhance the applicability of continuous technology in an actual manufacturing environment.
Curcumin is a polyphenol that is commonly used for its perceived health benefits. However, the absorption efficacy of curcumin is too low to exhibit beneficial effects. We have successfully developed ...a highly absorptive curcumin dispersed with colloidal nano-particles, and named it THERACURMIN. The absorption efficacy of THERACURMIN was investigated and compared with that of curcumin powder. The area under the blood concentration–time curve (AUC) after the oral administration of THERACURMIN was found to be more than 40-fold higher than that of curcumin powder in rats. Then, healthy human volunteers were administered orally 30 mg of THERACURMIN or curcumin powder. The AUC of THERACURMIN was 27-fold higher than that of curcumin powder. In addition, THERACURMIN exhibited an inhibitory action against alcohol intoxication after drinking in humans, as evidenced by the reduced acetaldehyde concentration of the blood. These findings demonstrate that THERACURMIN shows a much higher bioavailability than currently available preparations. Thus, THERACURMIN may be useful to exert clinical benefits in humans at a lower dosage.
Previous studies have shown that green tea catechins (GTCs) have beneficial effects on obesity and metabolic syndromes. In this study, we prepared kosen-cha from green tea using high pressure ...extraction, to reduce the astringent taste of the green tea. We identified a large quantity of polymerized GTCs in kosen-cha. To investigate the effects of kosen-cha containing polymerized GTCs in obese Japanese patients, we designed an open-label pilot study in which 6 obese subjects (body mass index (BMI) >25 kg/m2) were administered kosen-cha (5 g/L/d) for 12 weeks. Body composition, serum lipids, insulin resistance, vascular functions, and cardiac hypertrophy were measured before and 12 weeks after kosen-cha administration. Kosen-cha showed no significant adverse effects on the patients. Body weights, BMI, waist circumferences, serum triglyceride (TG) levels, and homeostasis model assessment as an index of insulin resistance (HOMA-IR) levels were significantly decreased after the 12 weeks of administration. Flow-mediated dilation (FMD) (p = 0.0214), brachial-ankle pulse wave velocity (baPWV)(p = 0.0141), left ventricular mass indexes (p = 0.0120), and plasma brain natriuretic peptide (BNP) (p = 0.0144) were significantly improved. Overall, kosen-cha reduced obesity and improved insulin resistance, vascular function, and cardiac hypertrophy, indicating its preventive potential in obesity and metabolic syndrome.
This study aimed to improve and investigate the oscillation dynamics and levitation stability of acoustically levitated water droplets. Contactless sample manipulation technology in mid-air has ...attracted significant attention in the fields of biochemistry and pharmaceutical science. Although one promising method is acoustic levitation, most studies have focused on a single sample. Therefore, it is important to determine the stability of multiple samples during acoustic levitation. Here, we aim to understand the effect of multiple-sample levitation on levitation stability in acoustic fields. We visualized the oscillatory motion of multiple levitated droplets using a high-speed video camera. To characterize the dynamics of multiple levitating droplets, the oscillation frequency and restoring force coefficients of the levitated samples, which were obtained from the experimental data, were analyzed to quantify the droplet–droplet interaction. The oscillation model of the spring-mass system was compared with the experimental results, and we found that the number of levitating droplets and their position played an important role in the levitation stability of the droplets. Our insights could help us understand the oscillatory behavior of levitated droplets to achieve more stable levitation.
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