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This study investigated the effect of magnetic particle size and volume fraction on the shear yield stress and dynamic viscosity of magnetorheological fluids. Magnetorheological fluids with varying volume fractions of micro‐ and nanoscale magnetic particles were prepared. A plate‐on‐plate shear test bench was constructed to evaluate the fluids under a constant shear rate, with the applied current ranging from 0 A to 1.2 A. Results indicated that the shear yield stress initially increased and then decreased as the volume fraction of magnetic nanoparticles increased, reaching a maximum of 47 kPa at a volume fraction of 7 %. However, the excessive addition of magnetic particles or large‐diameter particles led to settling and reduced stability of the fluids. The findings suggest that optimizing the size and volume fraction of magnetic particles is crucial for maximizing the shear yield stress of magnetorheological fluids. [ABSTRACT FROM AUTHOR]

If magnetorheological (MR) fluids are stored in porous materials, when excited by the external magnetic field, MR fluid will be drawn out and produce MR effect, which could be used to solve the following problems of the MR damper, such as the seal, volume and the cost of MR fluid damper. In this paper, the effect of structure of metal foams on the performance of MR fluid is investigated; the relationship between the penetrability and the porosity of the metal foams is measured, the change of MR fluid performance flowing though the metal foams is obtained. It shows that, after flowing through metal foams, the change of performance of MR fluid is about 2.5%. Compared to the sponge, the porous metal foams have the obvious advantages in high porosity and rigidity, which provide a convenient and low-cost way to design the MR damper. [ABSTRACT FROM AUTHOR]

The investigation of produced magnetorheological effect using porous materials (sponges, metal foams, etc.) to store MR fluids is a hot research topic, which can be used to solve the problem of dynamic seals and high cost for conventional MR fluid dampers. In this paper, the effect of the additional volume of MR fluid on the mechanical properties of metal foam MR materials is proposed. A set of plate-on-plate shearing test rigs is built up to evaluate experimentally the relationship between the mechanical properties (mainly shear torque) and the additional volume of this kind of metal foam MR materials in different currents and metal foams, which validates the effect of the MR fluid additional volume on the mechanical properties of metal foam MR materials. [ABSTRACT FROM AUTHOR]

In the present study, a sequential extraction procedure, recommended by the Community Bureau of Reference (BCR), was used for the fractionation of the heavy metals Cu, Zn, Pb and Cd in sewage sludge and its residues produced after pyrolysis at different temperatures from 250 to 700 °C. The results show that, in the sludge sample, the sum of the percentages of the reducible and oxidizable fractions for all metals except Cu was very high (65.4% for Cd, 85.7% for Pb, 78.7% for Zn), whereas the sum of the percentages of the oxidizable and residual fractions for Cu was very high (88.8%). The same result could be attained in the residues. Statistical analysis shows that at low temperatures the variation in pyrolysis temperature did not effectively contribute to the distribution of metal speciation in the residues. Meanwhile a modified Toxicity Characteristic Leaching Procedure (TCLP) was employed to determine the leachability of these four metals. The result indicates that the TCLP concentration of Cu, Zn, Pb and Cd dropped sharply after the temperature reached 350 °C, 550 °C, 500 °C and 400 °C respectively, which means pyrolysis can enhance the stability of these four metals when the temperature is high enough. [ABSTRACT FROM AUTHOR]

In this work we report experimental evidence for the weak high-temperature ferromagnetism in Bi 1- x R x FeO 3 ( R = Dy, Y) compounds by systematic characterizations, excluding the possible side-effects from other iron-based impurities. Remarkable saturated magnetic moment was observed in the Y-substituted samples, Bi 1- x Y x FeO 3 , which is larger than the moment obtained in Bi 1- x Dy x FeO 3 , the Dy-substituted samples with antiferromagnetic background. The physical origin of the weak ferromagnetic transition is discussed and serious lattice distortions have been identified based on the x-ray diffraction and Raman scattering data, although the rhombohedral structure symmetry remains unchanged upon the substitutions. It is believed that the structural distortion suppressed cycloid spin structure is the main factor for the enhanced magnetization in Bi 1- x R x FeO 3 compounds. Additionally, the Dy 3+ -Fe 3+ antiferromagnetic coupling, which strengthens the antiferromagnetic interaction in Bi 1- x Dy x FeO 3 compounds, acts as the driving force for the magnetic discrepancy between Bi 1- x Y x FeO 3 and Bi 1- x Dy x FeO 3 samples., (© 2021 IOP Publishing Ltd.)

Objective: To evaluate the accuracy of diffusion weighted magnetic resonance imaging (DWI-MRI) combined with high resolution temporal bone CT (HRCT) in the location diagnosis of middle ear cholesteatoma and its value in the postoperative follow-up. Methods: 134 patients with inital cholesteatoma and 22 patients with suspected recurrent cholesteatoma were selected for HRCT, conventional MRI and DWI examination. Based on the intraoperative and pathological diagnosis, DWI and HRCT images were combined to evaluate the consistency between the lesion location and invasion area of the initial cholesteatoma and intraoperative lesions. The results of HRCT and DWI in the diagnosis of recurrent middle ear cholesteatoma were statistically analyzed to evaluate their diagnostic efficacy. Results: The accuracy rate of DWI combined with HRCT was 90.3%.The sensitivity, specificity, positive predictive value and negative predictive value of HRCT and DWI in the diagnosis of recurrent middle ear cholesteatoma were 27.8%, 75.0%, 83.3%, 18.8% and 100%, 75.0%, 94.7% and 100%, respectively, and the Kappa values consistent with the pathological results were 0.024 and 0.843, respectively. Chi-square test confirmed that there were differences in the diagnosis between groups ( P< 0.001). Conclusions: Combined with the high sensitivity of DWI and the high resolution of HRCT, the accuracy of preoperative positioning of the newly diagnosed cholesteatoma can be improved and surgery strategy can be guided. DWI is also of high diagnostic value for recurrent cholesteatoma in the middle ear.

Objective: To analyze the related factors of portable monitoring and polysomnography in simultaneous monitoring of suspected OSAHS cases. To evaluate the application of portable monitoring in the diagnosis of OSAHS. Method: All patients underwent a simultaneous monitoring of both portable monitoring and polysomnography. Both the parameters of apnea hypopnea index (AHI), lowest oxygen saturation (LSaO₂), mean oxygen saturation (MSaO₂), percentage of time with an oxygen saturation below 90%(CT90%), oxygen desaturation index (ODI), the number of apnea and hypopnea were collected and analyzed. Result: Both the portable monitoring and polysomnography showed 39 cases met the diagnostic criteria for OSAHS. Polysomnography showed 26 severe cases, 8 moderate cases and 5 mild case. Portable monitoring showed 30 severe cases, 5 moderate cases and 4 mild cases. Comparing portable monitoring with polysomnography, the parameter of AHI had a significant difference. MSaO₂, LSaO₂, CT90%, ODI, the number of apnea and hypopnea had no significant difference. Conclusion: Compared portable monitoring's indicators with polysomnography's indicators, both correlated well. Portable monitoring has a high diagnostic value. But the diagnostic accuracy in the severity of the disease should be improved., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.)

A simple and rapid method has been developed for simultaneous determination of cholesterol and alpha-tocopherol in eggs. The method involves alcoholic KOH saponification of the samples, extraction with petroleum ether, and determination by wide-bore capillary gas chromatography. The recoveries of cholesterol and alpha-VE in eggs were 91.0%-93.3% and 82.5%-95.0%, with RSDs of 2.7%-3.1% and 4.9%-6.9% respectively.

A simple method for the analysis of residual benzene, toluene and N,N-dimethyl formamide (DMF) in acrylic fabrics by wide-bore capillary gas chromatography is presented. The sample was extracted by carbon disulfide (CS2) for an hour. The results showed that this is a rapid and sensitive method with less interferences and fairly good precision. The detection limits were 0.1, 0.1 and 2.0 ng for benzene, toluene and DMF respectively. The recoveries were 93.3%-101.8% and coefficients of variation were 2.0%-3.4%.

Morphine elicits a series of adverse effects including the inhibition of intestinal motility in addition to the therapeutic benefit of alleviating postoperative pain. To ascertain the role of electroacupuncture (EA) in diminishing those detrimental effects on recovery, we imitated the clinical procedures in rabbits. Morphine was given via a preimplanted cannula within spinal subarachnoid space, while the duodenal motility, respiration rate and arterial pressure were simultaneously recorded. It was found that morphine (6 mg/rabbit, IT) markedly suppressed duodenal peristalsis, decreased respiration rate throughout 90 min observation. When EA was administered together with morphine, peristalsis of the duodenum was much less inhibited (P < 0.05, vs morphine alone group), but no significant improvement of respiratory depression was noticed (P > 0.05), nor obvious change of arterial pressure in both groups. The results strongly recommend extensive application of EA in postoperative care, so as to decrease both the required dosage of morphine and the subsequent occurrence of postoperative ileus, while attaining sufficient analgesia.

In anther culture of Panax ginseng, its callus formation showed a wide adaptability to culture media. Large numbers of calli were induced on media exhibiting better effects of induction. Supplements of 5 mg 2,4-D/1 and 1 mg KT/1 to the media proved to be much effective. Regeneration of the whole plantlets from anther culture of Panax ginseng is usually quite difficult. During the past three years, however, sixteen of the 100 medium formulae tested were proved to be suitable. The formulae of MS + 0.5 mg BA/1 + 2 mg GA/1 + 1000 mg LH/1 + 3% sucrose were considered good and effective. A visibly differentiated body, which was light-milky white and later turned into a light green spot, was formed 40 days after the callus was transferred to the differentiation media. This body differentiated subsequently into buds, roots and, eventually, seedlings. The embryoid clones have been established in order to maintain its ability of continual differentiation into plantlets through successive culturings of many generations. The test-tube ginseng thus formed were transferred to regular flowerpots and grew well. Based upon chromosome examination of the callus cells and the root tips, we tentatively affirmed that the majority of these regenerated from anther of Panax ginseng were originated from pollen cells.