Search

It is crucial to better understand the magnetization reversal process between soft and hard magnets and to achieve a high maximum energy product in thick composite multilayers. In this study, we find that the exchange interactions dominate in soft–hard-magnetic composite bilayers, while dipole interactions are predominant in soft–hard-magnetic composite trilayers. Based on the first-order reversal curve, magnetization reversal models are developed for both the thick composite bilayer and trilayer. Dipole interactions play an important role in the long range, resulting in higher coercivity and remanence in the thick trilayer. A multilayer in a stacked trilayer structure is achieved, which is composed of thick films with a perpendicular magnetic anisotropy at a thickness of up to 16 μm. The enhanced dipole interactions lead to a remanent polarization of 1 T and a maximum energy product of 22.5 MGOe. This work contributes to the preparation of thick films with a high maximum energy product for applications in magnetic microelectromechanical systems. [ABSTRACT FROM AUTHOR]

Magnetic properties and coercivity mechanism of an anisotropic Ce–Nd–Fe–B film with a high Ce content (70 at. % Nd is replaced by Ce) have been investigated. After grain boundary diffusion with Tb layers, an enhancement of coercivity from 4150 to 9250 Oe is observed. Combining the initial magnetization curves, micromagnetic theory, and in-siut observation of magnetic domains in the demagnetization process, it is confirmed that the coercivity mechanism for the high-Ce-content magnets is the mixed type dominated by the pinning mechanism. Moreover, as the thickness of the Tb diffusion layer increases, the pinning center of domain walls changes from narrow planar inhomogeneities to wide planar inhomogeneities. A growing role of pinning plays in determining the coercivity of samples with increasing the thickness of Tb layer due to the increase in magnetocrystalline anisotropy after Tb substitution in the RE2Fe14B phase. In addition, the CeFe2 intergranular phase leads to the enhancement of coercivity due to decoupling the hard magnetic phase grains. Our results provide an insight into the coercivity mechanism of high-Ce-concentration Ce–Nd–Fe–B magnetic materials and promote the comprehension of the effect of Tb diffusion in the magnetization reversal process. [ABSTRACT FROM AUTHOR]

In composite magnets, an in-depth understanding of magnetization reversal behaviors promotes optimizing the structure design of a magnet and improving its performance. In this work, the perpendicular magnetic anisotropic Ta/La–Pr–Fe–B/Dy/La–Pr–Fe–B/Ta multilayers have been prepared by adjusting the thickness of the Dy layer. The domain reversal evolutionary procedure has been investigated in different aspects including the characterization of domain morphology, micromagnetic analysis, and irreversible reversal distribution. It is confirmed that the nucleation mechanism is dominant in determining the coercivity of the multilayers with Dy diffusion. Dy diffusion helps to enhance the coercivity of the multilayers. The formation of Dy-containing hard magnetic phases and rare-earth-rich grain boundary phases by adding the Dy element leads to a strong nucleation field and isolation of hard magnetic phase grains, respectively. Our results aid in the understanding of magnetization reversal behaviors and enhance the magnetic properties of highly abundant rare-earth permanent magnetic multilayer films with the doping element. [ABSTRACT FROM AUTHOR]

The magnetic properties and the possible interaction mechanisms of anisotropic soft- and hard-magnetic multilayers have been investigated by altering the thickness of different kinds of spacer layers. The metal Ta and the insulating oxides MgO, Cr2O3 have been chosen as spacer layers to investigate the characteristics of the interactions between soft- and hard-magnetic layers in the anisotropic Nd-Dy-Fe-Co-B/α-Fe multilayer system. The dipolar and exchange interaction between hard and soft phases are evaluated with the help of the first order reversal curve method. The onset of the nucleation field and the magnetization reversal by domain wall movement are also evident from the first-order-reversal-curve measurements. Reversible/irreversible distributions reveal the natures of the soft- and hard-magnetic components. Incoherent switching fields are observed and the calculations show the semiquantitative contributions of hard and soft components to the system. An antiferromagnetic spacer layer will weaken the interaction between ferromagnetic layers and the effective interaction length decreases. As a consequence, the dipolar magnetostatic interaction may play an important role in the long-range interaction in anisotropic multilayer magnets. [ABSTRACT FROM AUTHOR]

The effect of sintering process on the electrical properties of CaCu3Ti4O12 (CCTO) ceramic dielectrics were investigated in this paper. It was found that grain size is affected by sintering and the nonlinear current-voltage (I-V) property will decrease with the increased sintering time. Also, the frequency and temperature dependences of dielectric permittivity and loss in the ranges of 10-1-107 Hz and 130-270 K were studied. Two relaxation processes with activation energy of 0.51 eV and 0.10 eV, respectively, were found in the frequency dependence of tan δ and Cole-Cole planes, which can be interpreted in terms of insulating grain boundaries and semiconducting grains. It was suggested that grain boundary Maxwell-Wagner relaxation and ionization of oxygen vacancy VO++, proposed as extrinsic and intrinsic relaxations, are responsible for the dielectric behaviors of CCTO ceramics. [ABSTRACT FROM AUTHOR]

The combustion of anthracite and bituminite blends with different bituminite particle size was investigated with thermogravimetric analysis (TGA). It is indicated in the results that the increase of bituminite particle size may influence the pyrolysis of blends and consequently the decomposition of blends moved to higher temperature zones with the increase of bituminite particle size. However, the negative influence of specific area is not that significant to some bituminite and anthracite mixtures, the comprehensive combustion behavior of blends was stable when particle size of some bituminie PC was increased from 0,074 mm to 0,150 mm. [ABSTRACT FROM AUTHOR]

Although a variety of factors underlying diapause have been identified in arthropods and other organisms, the molecular mechanisms regulating diapause are still largely unknown. Here, to better understand this process, we examined diapause-associated genes in the two-spotted spider mite, Tetranychus urticae, by comparing the transcriptomes and proteomes of early diapausing and reproductive adult females. Amongst genes underlying diapause revealed by the transcriptomic and proteomic data sets, we described the noticeable change in Ca2+-associated genes, including 65 Ca2+-binding protein genes and 23 Ca2+ transporter genes, indicating that Ca2+ signalling has a substantial role in diapause regulation. Other interesting changes in diapause included up-regulation of (1) glutamate receptors that may be involved in synaptic plasticity changes, (2) genes involved in cytoskeletal reorganization including genes encoding each of the components of thick and thin filaments, tubulin and members of integrin signalling and (3) genes involved in anaerobic energy metabolism, which reflects a shift to anaerobic energy metabolism in early diapausing mites. [ABSTRACT FROM AUTHOR]

Intestinal transit is accelerated by volume distension and slowed by nutrient load. We hypothesized that the accelerating effect of volume distension might overcome the slowing effect of nutrient. To test this hypothesis, we compared intestinal transit in five dogs equipped with duodenal and mid-intestinal fistulas. The proximal half of the small intestine was perfused with 60 mM oleate, while the distal half of the small intestine was either perfused with buffer (with distension) or left unperfused (without distension). We found that intestinal transit was slowed by oleate (with marker recovery reduced from 85.8 +/- 5.3 to 39.4 +/- 7.5%) (P < 0.01) and that volume distension accelerated intestinal transit so that marker recovery increased from 39.4 +/- 7.5 without distension to 60.8 +/- 6.3% with distension (P < 0.05). We concluded that intestinal transit is accelerated by volume distension during fat-induced jejunal brake. [ABSTRACT FROM AUTHOR]

Patients with fat intolerance complain of early satiety, bloating, nausea, and vomiting. Since these symptoms are similar to those of patients with postgastrectomy dumping syndrome, we hypothesized that fat intolerance may be associated with early, rapid gastric emptying. Using a three-meal gastric emptying study, we compared gastric emptying in nine patients with a history of fat intolerance and nine normal volunteers. On three separate days, 500-ml radiolabeled test meals containing 0, 15, or 60 g of fat were studied. The percentages of the test meal emptied at 15 and 60 min were analyzed by repeated measures two-way ANOVA. At 15 min (p < 0.05) but not 60 min, gastric emptying was faster in patients than normals. Gastric emptying at 15 min (p < 0.001) and 60 min (p < 0.001) depended on the dose of fat. We conclude that fat intolerance is associated with early, rapid gastric emptying. [ABSTRACT FROM AUTHOR]

Fat in the proximal and distal gut inhibits intestinal transit as the jejunal brake and the ileal brake. It is unknown, however, whether the intestinal transit response to fat in the proximal vs distal gut is different. Since surgical removal of the distal small intestine induced faster transit and greater steatorrhea than removal of the proximal small intestine, we hypothesized that the ileal brake inhibited intestinal transit more potently than the jejunal brake. In six dogs equipped with duodenal (10 cm from pylorus) and midintestinal (160 cm from pylorus) fistulas, we compared intestinal transit across an isolated 150-cm test segment (between fistulas), while 0 (buffer), 15, 30, or 60 mM oleate was delivered into either the proximal (between fistulas) or the distal (beyond the midintestinal fistula) half of the gut. The half of the gut not receiving oleate was perfused with buffer. Buffer perfused into both the proximal and the distal half of the gut served as the control. A meal was administered and diverted completely out of the duodenal fistula so that the studies were all done in the fed state. Intestinal transit was measured by counting for the recovery of a radioactive marker from the temporarily diverted output of the midintestinal fistula. We found that (1) intestinal transit was inhibited more potently by oleate in the distal than in the proximal half of the gut (region effect; P < 0.01), (2) oleate inhibited intestinal transit in a load-dependent fashion (dose effect; P < 0.05), and (3) load-dependent inhibition of intestinal transit by oleate depended on the region of exposure (interaction between load and region; P < 0.01). We conclude that intestinal transit is more potently inhibited by fat-induced ileal than jejunal brake. [ABSTRACT FROM AUTHOR]

Soy protein, in both intact and hydrolyzed forms, is widely used as the nitrogen source in infant and adult formulas. This protein is also consumed in vast quantities worldwide as soybean-based food products. Digestion is the rate-limiting step in the assimilation of proteins from the gut. As a result, intestinal transit must be slowed when a higher load of protein is available or when this nutrient is delivered in the intact rather than hydrolyzed form. However, little information is available on the effect of load and degree of hydrolysis of soy protein on intestinal transit and protein absorption. To test the hypothesis that inhibition of intestinal transit and protein absorption depend on the load of soy protein and the state of hydrolysis of this nutrient, we compared intestinal transit and protein absorption in dogs equipped with duodenal and midintestinal fistulas during intestinal perfusion with 0, 50, 100, or 200 g/L solutions of intact soy protein versus 0, 100, 200, 300, or 400 g/L solutions of hydrolyzed soy protein. We found that intestinal transit was slowed in a load-dependent fashion by intact (P < 0.001) and hydrolyzed (P < 0.05) soy protein. Soy protein inhibited intestinal transit more potently in the intact than hydrolyzed form (P < 0.05). A greater amount of protein was absorbed by the proximal half of the small intestine when soy protein was delivered in the hydrolyzed than intact form (P < 0.05), and the efficiency of protein absorption was maintained at a high and nearly constant level of 82.6 to 87.4% for intact soy protein and 89.0 to 92.3% for hydrolyzed soy protein. We conclude that in dogs intestinal transit and absorption of soy protein depend on the load and the degree of protein hydrolysis. [ABSTRACT FROM AUTHOR]

Mic rotopography and combustion characteristics of carbonized corn straw and pine charcoal as well as anthracite were investigated to compare the property of fuel and analyze the application of corn straw in industrial activity. The reduction process of hematite with different reducing agent was studied with thermogravimetric analysis. It is indicated in the results that the initial reduction temperature was lower when carbonized corn straw was blended with hematite and an ideal reduction rate can be achieved with a C/O of 1.1, while the reduction rate of pine charcoal to hematite was lower and higher C/O is needed for anthracite to obtain the same reduction rate. [ABSTRACT FROM AUTHOR]

In fluence of microwave irradiation on gasification behavior and crystallite parameters of coke samples was studied in this research. The results indicated that microwave irradiation have significant influence on the carbon structure and the reactivity of coke in CO2 atmosphere. The thermogravimetric results showed that the temperature of coke at different conversion rates of 10 %, 20 % and 30 % were reduced by 20 °C, 30 °C and 50 °C respectively. Simultaneously, microwave irradiation may lead to variation in lateral size and stacking height of crystallite and subsequently reduce the gasification reaction rate of coke in CO2 atmosphere. [ABSTRACT FROM AUTHOR]

This paper presents a microfluidic system enabling continuous characterization of instantaneous Young's modulus (Einstantaneous) of single cells in suspension. In this study, cells were aspirated continuously through a constriction channel while cellular entry processes were monitored using a high-speed camera. Numerical simulations were conducted to model cellular entry process into the constriction channel where a visco-hyperelastic solid was used to model biological cells and the cellular friction with the constriction channel wall (ƒc) was properly addressed. Both experimental observations and numerical simulations confirmed the two-stage cellular entry process into the constriction channel: an instantaneous jump into the channel quantified by instantaneous aspiration length (Linstantaneous) followed by a creeping increase in aspiration length terminated by transitional aspiration length (Ltransitional). Numerical simulations reveal that Linstantaneous and Ltransitional are reversely proportional to Einstantaneous, which are affected by ƒc regardless of other cellular viscoelastic parameters. By combining measured Linstantaneous and Ltransitional with these obtained from numerical simulations, Einstantaneous and ƒc were quantified as 3.48 ± 0.86 kPa and 0.39 ± 0.11 for A549 cells (ncell = 199) and 2.99 ± 0.38 kPa and 0.37 ± 0.02 for 95C cells (ncell = 164). As a platform technology, this method can be used to characterize Einstantaneous of various cell types in a continuous manner for cellular biophysical property characterization. [ABSTRACT FROM AUTHOR]

Objective: To explore the value of predicting shunt-dependent hydrocephalus (SDHC) in patients with aneurysmal subarachnoid hemorrhage (aSAH) based on whole brain CT perfusion(CTP) and clinical data within 24 hours at admission. Methods: The clinical and imaging data of aSAH patients who received interventional embolization in our hospital were retrospectively collected from March 2018 to August 2022. All patients underwent one-stop whole brain CT examination within 24 hours after symptom onset, and the qualitative and quantitative CTP parameters were obtained after post-processing. Follow-up was conducted once every 2 months by consulting electronic medical records or by telephone for 6 months. According to whether SDHC occurred or not, the patients were divided into SDHC group and non-SDHC group. The differences between the two groups were compared. Logistic regression model was used to analyze and determine the predictive factors of SDHC, and the SDHC predictive model was established. The effectiveness of the predictive model was evaluated by drawing the receiver operating characteristic (ROC) curve of the subjects. Results: A total of 414 patients were included, including 132 males and 282 females, aged (59±11) years. 17.6%(73/414) patients had SDHC. There were significant differences in the occurrence of acute hydrocephalus, the World Neurosurgical League Scale (WFNS), the Hunt-Hess scale, the modified Fisher score (mFS), and the qualitative and quantitative parameters of CTP between the two groups (both P <0.001). Multivariate logistic regression analysis showed that acute hydrocephalus ( OR =8.621, 95% CI : 4.237-17.542),old age ( OR =1.107, 95% CI : 1.068-1.148), high mFS and high Hunt-Hess classification ( OR =3.740, 95% CI : 1.352-10.342) were the risk factors of SDHC in aSAH patients, and high mean cerebral blood flow (mCBF) ( OR =0.931, 95% CI : 0.885-0.980) was a protective factor of SDHC.The area under ROC curve (AUC) of the prediction model constructed by these five variables was 0.923(95% CI : 0.89-0.95), with 84.5% sensitivity and 87.7% specificity. Conclusion: The mCBF and acute hydrocephalus, age, mFS and Hunt-Hess classification within 24 hours at admission can be used to predict SDHC for aSAH patients.

Objective: To explore the safety and myocardial protection efficacy of del Nido cardioplegia in adult cardiac and major vascular surgery with long aortic cross-clamp (ACC) time. Methods: A total of 2 536 patients who underwent adult cardiac and major vascular surgery with ACC time>90 min at Beijing Anzhen Hospital from March 2018 to March 2023 were collected. The patients were divided into two groups according to the type of cardioplegia solution: the del Nido cardioplegia solution group (DC group) and the cold blood cardioplegia solution group (BC group). Preoperative baseline data of the patients (age, gender, comorbidities, ejection fraction, etc) were adjusted using propensity score matching (PSM). Cardiopulmonary bypass (CPB) time, ACC time, total amount of cardioplegia solution, in-hospital mortality rate, length of intensive care unit (ICU) stay, mechanical ventilation time, postoperative complications, left ventricular ejection fraction, and troponin levels were compared between the two groups. Results: After PSM, a total of 306 patients were included, including 223 males and 83 females, with a mean age of (52.0±12.3) years. There were 153 cases in the DC group and 153 cases in the BC group. Compared with the DC group, the cross-clamp time was longer [109(100, 150) min vs 102(91, 133) min, P <0.001], the rate of return to spontaneous rhythm was lower [51.6% (79/153) vs 86.9%(133/153), P <0.001], and intraoperative peak glucose was higher [12.6 (6.5, 15.9) mmol/L vs 10.1 (8.5, 12.4) mmol/L, P= 0.005] in the BC group. In addition, perioperative mortality [4.6% (7/153) vs 3.3% (5/153), P =0.132], stroke[3.9% (6/153) vs 3.3% (5/153), P =0.759], renal insufficiency [3.3% (5/153) vs 6.5% (10/153), P =0.186], atrial fibrillation [4.6% (7/153) vs 2.6% (4/153), P =0.652] and low cardiac output syndrome [3.9% (6/153) vs 4.6% (7/153), P =0.716] did not differ between the two groups. Compared with BC group, DC group had lower level of high sensitivity troponin (hsTnI) [1.2 (0.8, 1.8) μg/L vs 1.3 (0.9, 2.3) μg/L, P =0.030] and creatine kinase isoenzyme (CK-MB) [31.0 (20.0, 48.9) μg/L vs 37.0 (24.0, 58.9) μg/L, P =0.011] at 24 h postoperatively, and shorter length of ICU stay [35.6 (19.8, 60.5) h vs 42.6 (21.9, 83.6) h, P =0.015] and mechanical ventilation time [20.5 (15.5, 41.0) h vs 31.5 (17.1, 56.0) h, P =0.012]. Subgroup analysis showed that in the 120-180 minute subgroup, patients in the DC group had a shorter cross-clamp time [132 (124, 135) min vs 136 (124, 138) min, P <0.001], while levels of hsTnI [1.6 (1.1, 2.0) μg/L vs 1.4 (1.0, 2.6) μg/L, P =0.030] and CK-MB [38.8 (23.5, 55.5) μg/L vs 37.0 (24.5, 62.3) μg/L, P =0.011] were higher than those in the BC group. Conclusions: In adult cardiac and major vascular surgery with ACC times>90 min, comparable myocardial protection is observed with the use of DC compared with BC. Additional advantages in glycemic control, return to spontaneous rhythm, and improved surgical procedures make DN an attractive alternative for myocardial protection in adult cardiac surgery.