Dynamically Rotating Magnetic Levitation to Characterize the Spatial Density Heterogeneity of Materials.

Magnetic levitation (MagLev) is a promising technology for density-based analysis and manipulation of nonmagnetic materials. One major limitation is that extant MagLev methods are based on the static balance of gravitational-magnetic forces, thereby leading to an inability to resolve interior differences in density. Here a new strategy called "dynamically rotating MagLev" is proposed, which combines centrifugal force and nonlinear magnetic force to amplify the interior differences in density. The design of the nonlinear magnetic force in tandem with centrifugal force supports the regulation of stable equilibriums, enabling different homogeneous objects to reach distinguishable equilibrium orientations. Without reducing the magnetic susceptibility, the dynamically rotating MagLev system can lead to a relatively large change in orientation angle (∆ψ > 50°) for the heterogeneous parts with small inclusions (volume fraction VF = 2.08%). The rich equilibrium states of levitating objects invoke the concept of levitation stability, which is employed, for the first time, to characterize the spatial density heterogeneity of objects. Exploiting the tunable nonlinear levitation behaviors of objects provides a new paradigm for developing operationally simple, nondestructive density heterogeneity characterization methods. Such methods have tremendous potential in applications related to sorting, orienting, and assembling objects in three dimensions.

Self-vectoring electromagnetic soft robots with high operational dimensionality.

Soft robots capable of flexible deformations and agile locomotion similar to biological systems are highly desirable for promising applications, including safe human-robot interactions and biomedical engineering. Their achievable degree of freedom and motional deftness are limited by the actuation modes and controllable dimensions of constituent soft actuators. Here, we report self-vectoring electromagnetic soft robots (SESRs) to offer new operational dimensionality via actively and instantly adjusting and synthesizing the interior electromagnetic vectors (EVs) in every flux actuator sub-domain of the robots. As a result, we can achieve high-dimensional operation with fewer actuators and control signals than other actuation methods. We also demonstrate complex and rapid 3D shape morphing, bioinspired multimodal locomotion, as well as fast switches among different locomotion modes all in passive magnetic fields. The intrinsic fast (re)programmability of SESRs, along with the active and selective actuation through self-vectoring control, significantly increases the operational dimensionality and possibilities for soft robots.

Pump-free microfluidic magnetic levitation approach for density-based cell characterization.

Magnetic levitation (MagLev) provides a simple but promising method for density-based analysis and detection down to the individual cell level. However, each existing MagLev configuration for the single-cell density measurement, mainly consisting of a capillary (∼50 mm) placed between two magnets, yields a fairly low sample utilization because of no knowledge about the sample cells in the regions other than the limited microscope vision. Moreover, the quantitative analysis may be affected due to the unclearly defined measurement area, which is specifically associated with the uneven magnetization of magnets, cell size, degree of aggregation. In this work, we explore a pump-free microfluidic magnetic levitation approach for density-based cell characterization, enabling sensitive and effective cellular density measurement on small sample volumes. The microfluidic MagLev comprises a pump-free microfluidic chip placed between two ring magnets with like poles facing. With no external pumps, connectors or control facility, much smaller amounts of fluids (∼4 µL) could be driven automatically in the entire microchannel in 16 s. Based on the pump-free mechanism, unique density signatures of cells from different lineages (ARPE-19, HCT116, HeLa, HT1080, Huh7) are characterized by monitoring the levitation profiles. Furthermore, variation in density of A549 lung cancer cells subjected to a drug treatment are observed in our platform, allowing evaluation of the efficacy of the drug treatment at the individual cell level. Thereby, the proposed pump-free microfluidic MagLev platform, a low-cost, fully automatic and portable design for label-free density-based cell characterization, provides a universal detection tool that operates efficiently within small-volume environments.

Electrically Activated Soft Robots: Speed Up by Rolling.

Soft robots show excellent body compliance, adaptability, and mobility when coping with unstructured environments and human-robot interactions. However, the moving speed for soft locomotion robots is far from that of their rigid partners. Rolling locomotion can provide a promising solution for developing high-speed robots. Based on different rolling mechanisms, three rolling soft robot (RSR) prototypes with advantages of simplicity, lightweight, fast rolling speed, good compliance, and shock resistance are fabricated by using dielectric elastomer actuators. The experimental results demonstrate that the impulse-based and gravity-based RSRs can move both stably and continuously on the ground with a maximum speed higher than 1 blps (body length per second). The ballistic RSR exhibits a high rolling speed of ∼4.59 blps. And during its accelerating rolling process, the instantaneous rolling speed of the robot prototype reaches about 0.65 m/s (13.21 blps), which is much faster than most of the previously reported locomotion robots driven by soft responsive materials. The structure design and implementation methods based on different rolling mechanisms presented can provide guidance and inspiration for creating new, fast-moving, and hybrid mobility soft robots.

[Study on the encapsulation technique of high purity gamma-linolenic acid, part 1--saponification reaction and saponification value].

OBJECTIVE: To measure the saponification value and fatty acid formation of evening primrose oil, to study the effects of pH value on production yield and fatty acid formation during the saponification reaction, and to provide rationales for the selection of raw material, the enhancement of production yield of saponification, and the encapsulation of gamma-linolenic acid with urea. METHOD: To measure fatty acid's formation with gas chromatographic method and to measure the saponification value. RESULT: The content of gamma-linolenic acid is 7%-10% in evening primrose oil. The content of gamma-linolenic acid is inversely correlated with that of unsaturated fatty acid. The saponification value, the amount of KOH for saponification of evening primrose oil, and the pH value for subsequent isolations of oils are determined. From the measurement of fatty acids of evening primrose oil in two different cultivation locations, the content of gamma-linolenic acid is determined to be 7%-10%, unsaturated oils account for 90%. CONCLUSION: The saponification value of evening primrose oil is between 180-200, pH value of isolated oil is 1.5-2.0 after saponification reaction. Fatty acids mainly include palmitic acid, stearic acid, oleic acid, linolic acid and gamma-linolenic acid.

[Study on the encapsulation technique of high purity gamma-linolenic acid, part 1--Single factor, and two-factor tests for encapsulation process].

OBJECTIVE: To study the effects of all factors during the process of urea encapsulation of gamma-linolenic acid on the purity and yield. METHOD: To observe the material proportions, time, temperature and purity using single-factor and two-factor tests. RESULT: Single-factor test showed that the optimal ratio of all materials (oil, urea and 95% ethanol) was 1:3:8. A 30% purity after single encapsulation process was obtained, at the best temperature range was - 15 degrees C-20 degrees C, for 24 hours. Two-factor test showed that the optimal ratio of oil, urea and ethanol was 1:3:8, where the concentration of ethanol was 90%-95%. The purity reached 90% or higher, with three-time encapsulation process. CONCLUSION: An optimized process was identified where material ratios, encapsulation time, temperature, and ethanol concentrations were determined using single-factor and two-factor tests.

Effect of melatonin on the generation of nitric oxide in murine macrophages.

In the present investigation, the effects of melatonin on the generation of nitric oxide in stimulated murine macrophages were studied by electron paramagnetic resonance techniques, and the underlying mechanisms were discussed. Upon stimulation with lipopolysaccharide/interferon-gamma, macrophages generated a high concentration of nitric oxide. Melatonin pretreatment significantly inhibited the generation of nitric oxide. Western blot and reverse transcription polymerase chain reaction analysis showed that melatonin decreased the expression of inducible nitric oxide synthase at either the protein or mRNA level. Further investigation showed that melatonin significantly attenuated the nitration of cytoplasmic IkappaB-alpha, inhibited the degradation of IkappaB-alpha, and blocked the translocation of p65/RelA into the nuclei. The results suggest that melatonin inhibits the expression of inducible nitric oxide synthase by modulating the nuclear factor kappaB pathway.

Ameliorative effect of L-methionine on Pb-exposed mice.

The present investigation was carried out to study the ameliorative effects of L-Met (L-methionine) on Pb-exposed mice by the measurement of the weight gain, the weight of organs, the Hb content, the level of lipid peroxidation (LPO), and the Pb and Fe contents of selected organs and serum. Thirty mice were randomly divided into the healthy control group (A), the Pb control group (B), and the Pb+L-Met-treated group (C). Lead-induced depression of growth and Hb content was reversed when L-Met was added to the daily drinking water. The level of LPO of all the samples from group B was significantly higher than group A (p<0.05); however, in group C, it was lowered, especially that in the brain, kidney, and serum, which were not significantly different than normal (p>0.05). Significant enhancement of Pb content (p<0.05) and significant decrease of Fe content of all the samples in group B (p<0.05) were observed. However, dietary Met significantly lowered Pb concentration of all the samples (p<0.05) compared to that of the liver and kidney, reaching no significance in comparison to group A (p>0.05). The Fe concentration changed little (p>0.05). The result suggests that L-Met has an ameliorative effect on Pb-exposed mice.

[The improvement of taurine in learning and memory ability of rats exposed to lead].

OBJECTIVE: To investigate the improvement of taurine (Tau) in learning and memory ability of rats exposed to lead. METHODS: Forty Wistar rats were randomly divided into control group: treated with distilled water; lead group: treated with lead acetate (40 mg.kg(-1).d(-1)); lead-taurine group 1, 2, 3: lead acetate (40 mg.kg(-1).d(-1)) + different concentrations of taurine (100, 400, 800 mg.kg(-1).d(-1)). The ability of learning and memory of rats were measured weekly by spatial water maze test from the 5th to 8th week. At the end of the experiment, the rats were killed, the samples of blood and brain were taken for test. RESULTS: (1) The time of seeking anchorage of lead-Tau 800 mg group in the 6th, 7th, 8th week and that of lead-Tau 400 mg group in the 6th week were significantly lower than that of lead group (P<0.05). (2) Blood lead contents in lead-Tau 100 mg and lead-Tau 400 mg group [(510.9 +/- 57.56) microg/L, (485.40 +/- 98.85) microg/L] were different from those in lead group (P<0.05). (3) The content of malondialdehyde (MDA) and the activities of superoxide dismutase (SOD), nitric oxide synthase (NOS), acetylcholinesterase (AChE) in brain of lead-Tau 800 mg group and lead-Tau 400 mg group were also different from those in lead group (P<0.05 or P<0.01). The content of GSH and the activity of GSH-Px in lead-Tau 800 mg group were different from those in lead group (P<0.05) as well. CONCLUSION: Taurine could improve learning and memory ability of rats exposed to lead and may play a protective role in brain.

[Effect of L-methionine on trace elements in lead-intoxicated mice].

OBJECTIVE: To investigate the effect of L-methionine (L-Met) on the content of Zn, Cu, Mn, Fe in liver, brain, spleen and kidney of lead intoxicated mice. METHODS: Distilled water was given to 10 mice (normal control group) and lead acetate solution of 400 micro g/ml Pb(2+) to 20 mice to serve as drinking water for 10 days. The lead administration was then withdrawn and lead exposed mice were randomly divided into two groups: the lead control group took distilled water as drinking water for 4 weeks to serve as positive control, the other one took L-Met solution (0.5 mg/ml) as drinking water for 4 weeks (Pb + L-Met group) to serve as the treatment group. All the animals were sacrificed on the 1st day after 4 weeks, and the contents of Zn, Cu, Fe, Mn, Pb in liver, brain, spleen and kidney were measured by Inductively Coupled Plasma (ICP) Emission Spectrometry. RESULTS: Lead contents in liver, brain, spleen and kidney of Pb control group [(1.490 +/- 1.654) micro g/g, (3.470 +/- 2.757) micro g/g, (4.975 +/- 2.993) micro g/g, (0.066 +/- 0.001) micro g/g respectively], were higher than those in normal control group [(0.015 +/- 0.001) micro g/g, (0.009 +/- 0.007) micro g/g, (0.027 +/- 0.002) micro g/g, (0.006 +/- 0.015) micro g/g, P < 0.05] while Zn contents in liver, brain, spleen and Fe and Mn content in liver, brain, spleen and kidney in Pb control group were lower than those in normal control group (P < 0.05). Pb contents of brain, spleen and Cu content of kidney in Pb + L-Met group were higher than those in normal control group (P < 0.05). Zn contents of liver, brain, spleen, Fe contents of liver, brain, spleen, kidney, and Mn contents of brain, spleen in Pb + L-Met group were lower than those in normal control group (P < 0.05). Fe contents of liver, brain, Zn content of spleen, Cu content of kidney and Mn contents of liver, brain, spleen in the Pb + L-Met group were higher than those in the Pb control group (P < 0.05). The lead levels of four organs in the Pb + L-Met group were lower than those in the Pb control group (P < 0.05). CONCLUSION: Lead could be eliminated by L-Met, which may affect the distribution and metabolism of trace elements in mice.

Hypoglycaemic effect of a novel insulin buccal formulation on rabbits.

Transmucosal delivery is a suitable route for insulin non-injection administration. In this study, the hypoglycaemic effect of INSULIN BUCCAL SPRAY (IBS), a formulation with soybean lecithin and propanediol combined as absorption enhancer for insulin on diabetic rabbits and rats, were investigated. The hypoglycaemic rate was calculated and the pharmacodynamics and pharmacokinetics of the formulation in rabbits were studied. The results show that when the diabetic rabbits were administrated with IBS in dosages of 0.5, 1.5 and 4.5Ukg(-1), the blood glucose level decreased significantly compared with that of the control group and the hypoglycaemic effect lasted over 5h. The blood glucose decreasing rates are 22.4, 48.1 and 53.5%, respectively. The average bioavailability of IBS by buccal delivery versus subcutaneous injection is 29.2%. Meanwhile, the diabetic rats were administrated with IBS in dosages of 1.0, 3.0 and 9.0Ukg(-1), the blood glucose level decreased significantly compared with that of the control group and the hypoglycaemic effect lasted over 4h. The blood glucose decreasing rates are 24.6, 47.5 and 59.6%, respectively. Furthermore, the penetration of fluorescein isothiocyanate (FITC)-labelled insulin through rabbit buccal mucosa was investigated by scanning the distribution of the fluorescent probe in the epithelium using confocal laser scanning microscopy. The results revealed that FITC-insulin can pass through the buccal mucosa promoted by the enhancer and the passage of insulin across the epithelium includes both intracellular and paracellular routes. From the rabbit and rat experimental results showed that IBS is an effective buccal delivery system, which is promising for clinical trial and the future clinical application.