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The realization of a large low-field magnetoresistance (LFMR) effect in free-standing magnetic oxide films is a crucial goal toward promoting the development of flexible, low power consumption, and nonvolatile memory devices for information storage. La0.7Sr0.3MnO3 (LSMO) is an ideal material for spintronic devices due to its excellent magnetic and electronic properties. However, it is difficult to achieve both a large LFMR effect and high flexibility in LSMO films due to the lack of research on LFMR-related mechanisms and the strict LSMO growth conditions, which require rigid substrates. Here, we induced a large LFMR effect in an LSMO/mica heterostructure by utilizing a disorder-related spin-polarized tunneling effect and developed a simple transfer method to obtain free-standing LSMO films for the first time. Electrical and magnetic characterizations of these free-standing LSMO films revealed that all of the principal properties of LSMO were sustained under compressive and tensile conditions. Notably, the magnetoresistance of the processed LSMO film reached up to 16% under an ultrasmall magnetic field (0.1 T), which is 80 times that of a traditional LSMO film. As a demonstration, a stable nonvolatile multivalue storage function in flexible LSMO films was successfully achieved. Our work may pave the way for future wearable resistive memory device applications.

Topological magnetic domains exhibit many fascinating features and great potential in information storage and spintronics owing to their unique spin textures. In order to investigate the topological properties of the domain structures, the spontaneous evolutions of magnetic moments are evaluated by using Landau–Lifshitz–Gilbert equation. The equilibrium phase diagrams of the system with randomly, radial and axial distributed initial magnetic moments have been studied in detail. Simulation results show that the changes of quality factor (Q) and aspect ratio (T/D) lead to great differences in magnetization process under different initial magnetization states. Vortex, biskyrmion, skyrmion and bubble are formed as the value of Q gradually increases from 0 to 1. The system with Q 1.0 are arranged along the easy axis. When Q and T/D are in the range of 0.6 ~ 0.8 and 0.10 ~ 0.16, respectively, it is conducive to the formation of nontrivial topological domain. Biskyrmion is spontaneously formed in the system of Q = 0.6 and T/D = 0.12, proving that skyrmion-like domain can be generated in the absence of Dzyaloshinskii–Moriya interaction or external field.

痛风是由高尿酸血症引起单钠尿酸盐晶体沉积所致的一组疾病，急性痛风性关节炎以突发关节红肿、剧烈疼痛及自发性缓解为主要特征。巨噬细胞是人体内重要的固有免疫细胞，在痛风的不同阶段分化为不同表型，参与炎症的启动与缓解。本文就巨噬细胞在急性痛风发作及缓解中的作用机制进行阐述，以期为防治急性痛风发作提供新思路。.

多学科合作在临床工作中越来越受到重视，在特殊疾病的诊断和治疗中发挥着越来越重要的作用。海绵窦综合征病因比较复杂，治疗比较困难。现报道多学科合作成功诊治海绵窦综合征患者1例，希望以此提高临床医生对此病的认识。.

Background A combination of analgesic agents with different mechanisms can induce additive or synergistic analgesia. The N-type voltage-dependent calcium channel (N-VDCC) is a novel therapeutic target for pain control. In addition to providing effective pain relief when used alone, N-VDCC blockers produce synergistic analgesia when used in combination with opiates. However, the interaction between N-VDCC blockers and nonsteroidal anti-inflammatory drugs (NSAIDs) remains unclear. Methods Using isobolographic analysis and composite additive curve analysis, the antinociceptive interaction between ZC88, a selective N-VDCC blocker and ibuprofen, a classical NSAID, was investigated in two mouse models of visceral and somatic inflammatory pain. Results In the acetic acid writhing test, both ZC88 (10.5-42 mg/kg, intraperitoneally) and ibuprofen (50-200 mg/kg, orally) produced dose-dependent antinociception, with ED50 values of 27.2 and 100.5 mg/kg, respectively. ZC88 in combination with ibuprofen (ZC88 + ibuprofen) also induced significant antinociception, and isobolographic analysis revealed a synergistic interaction at 50% effect level. The experimental ED50 (ED50 mix ) of this combination (34.5 mg/kg) was significantly lower than the theoretical ED50 (ED50 add ; 63.8 mg/kg). Additionally, composite additive curve analysis displayed synergistic interaction at other effect levels. In the formalin test, ZC88 or ibuprofen alone significantly reduced late-phase rather than early-phase pain, with ED50 values of 31.3 and 123.9 mg/kg, respectively. Similarly, both isobolographic analysis and composite additive curve analysis revealed synergistic antinociception of ZC88 + ibuprofen (40.6 mg/kg of ED50 mix vs. 77.6 mg/kg of ED50 add ). Conclusion ZC88 in combination with ibuprofen produces synergistic antinociception in mouse models of somatic and visceral inflammatory pain. Significance Because ZC88 + ibuprofen achieves the same antinociceptive effect at lower doses, the use of this combination could result in fewer dose-related untoward effects. The potentiation of ZC88 on ibuprofen-induced antinociception indicates that N-VDCC blocker has potential benefit to treat severe inflammatory pain.

In this study, the martensite transformation of Ni37.5Co12.5Mn35Ti15 ribbon was studied and regulated by the electric field-induced strain in the PMN-PT substrate. The reversible magnetocaloric effect in the Ni37.5Co12.5Mn35Ti15/PMN-PT composite was enhanced by manipulating transition paths under the coupling of magnetic field and electric field, which is significantly important for applications in solid-state refrigeration. With the assistance of E = +8 kV/cm, the reversible entropy change increased from 19.5 to 25.7 J/kgK at 294.5 K. Meanwhile, the reversible cooling temperature span was also enlarged. Hence, the reversible refrigerant capacity was enhanced from 83 to 131 J/kg, and the increase ratio reached 58%. On this basis, an active magnetic regenerating cycle facilitated by an electric field was designed. This work provides an effective method for enhancing reversible caloric effects in first-order phase transition materials via electric fields.

Topological spin textures, such as magnetic skyrmion, have great promises in data storage applications due to their inherent stability. Contrary to the general idea, simulation results here indicate that spontaneous skyrmion equilibrium states can exist generally in certain materials without the assistance of Dzyaloshinskii-Moriya interaction, external fields or defects. The spin configurations are closely related to the variations of the magnetocrystalline anisotropy K1, exchange interaction A, and saturation magnetization MS. The system with low anisotropy is conducive to the formation of vortex, while a single domain can be formed in the large range of K1 and A in the system with small MS. Landau-Lifshitz-Gilbert equation is used to investigate the variations of different interaction energies in the formation of topological domains. In the range where skyrmions are formed, the anisotropic energy, exchange energy and demagnetization energy account for 40 ~ 80%, 10 ~ 20%, 10 ~ 40% of the total energy. Meanwhile, a phase diagram of equilibrium magnetic moment distribution under different intrinsic properties is obtained. The K1, A and MS values of skyrmions range from 1.6 ~ 2.5 × 105 J/m3, 1.6 ~ 6.8 × 10-12 J/m, and 7.1 ~ 8.8 × 105 A/m in this simulation. By adjusting the material parameters, various competing interactions in magnetic nanostructures can be controlled to form skyrmion textures, which provide important insights for understanding the formation mechanism of nontrivial topological domains.

The analysis method is developed to obtain dynamic characteristics of the rotating cantilever plate with thermal shock and tip-rub. Based on the variational principle, equations of motion are derived considering the differences between rubbing forces in the width direction of the plate. The transverse deformation is decomposed into quasi-static deformation of the cantilever plate with thermal shock and dynamic deformation of the rubbing plate under thermal shock. Then deformations are obtained through the calculation of modal characteristics of rotating cantilever plate and temperature distribution function. Special attention is paid to the influence of tip-rub and thermal shock on the plate. The results show that tip-rub has the characteristics of multiple frequency vibrations, and high frequency vibrations are significant. On the contrary, thermal shock shows the low frequency vibrations. The thermal shock makes the rubbing plate gradually change into low frequency vibrations. Because rub-induced vibrations are more complicated than those caused by thermal shock, tip-rub is easier to result in the destruction of the blade. The increasing friction coefficient intensifies vibrations of the rubbing plate. Minimizing friction coefficients can be an effective way to reduce rub-induced damage through reducing the surface roughness between the blade tip and the inner surface of the casing.

In order to reduce the RE-Fe-B material cost and balance the utilization of rare earth sources, misch metal substitution for Nd in the sintered magnet becomes of many interests. Under the process of fabricating high magnetic properties magnet, the strip-casting (SC) technique plays a key role, a series of rapidly solidified [(PrNd)1-xMMx]13.8FebalCo0.5Cu0.1Al0.6Ga0.07B5.9 (x = 0 ~ 1.00) (MM, Misch Metal) strips were manufactured. Subsequently, the phase constitution, microstructure and the intrinsic magnetic properties were measured. There are always stable RE2Fe14B phase in the strips with MM, which is similar to Nd-Fe-B strip. Whereas, when x ≥ 0.50, there exists REFe2 phase inevitably, and the amount of REFe2 phase gradually increases with increasing MM content. Magnetic measurements indicated that intrinsic magnetic properties, such as the saturation magnetization Ms and magneto-anisotropy field HA, deteriorate gradually by substituting PrNd with MM except for x = 0.35. For x = 0.35, the abnormal phenomenon is ascribed to Ce valence shifting toward +3 that is caused by lattice expanding. In addition, when x ≥ 0.50, La and Ce is prior to aggregate in the RE-rich phase clusters, and the content of Fe rises with the increase of MM, moreover, the interfaces between of RE2Fe14B phase and RE-rich phase become indistinct.

Compare with Ce–Fe–B crystalline magnets, the amorphous alloy exhibit interesting properties due to their domains, low anisotropy energy, and microstructure contribution. In order to investigate magnetic properties and microstructures of the amorphous Ce–Fe–B system with Co substituting for Fe, the ribbons with a nominal composition of Ce13.5(Fe79.5-xCox)B7 (x = 0, 3, 6, 9, 12) were prepared using vacuum melt spinner at a wheel speed of 50 m/s. The XRD and the corresponding SAED Pattern indicate the uniform amorphous microstructure is well maintained in each sample. These ribbons are magnetically soft and undergo a second order phase transition from ferromagnetic to paramagnetic state. With the increasing Co content, the Curie temperature almost linearly increases with temperature during 270 K and 410 K. Results from Lorentz Transmission Electron Microscopy (L-TEM) and micromagnetic simulation prove that the vortex domains can form spontaneously and stability in Ce–Fe–B amorphous materials no matter doping Co or not. The nontrivial topological domain structures found in experiments and numerical calculations have potential applications in the field of information storage, which is helpful to develop new applications of high abundance rare earth elements in functional materials.

In this study, we investigated the spatial distribution of Culex tritaeniorhynchus Giles, 1901 (Diptera: Culicidae) (the vector of Japanese B Encephalitis) and geo-environmental features (rice fields, forests, watercourses, and highways) correlated with their abundance in pigsties of Dao County, Hunan Province, China. First, light trapping in pigsties was carried out to determine vector density. Second, based on Advanced Land Observing Satellite remote-sensing datasets, spatial datasets of mosquito density and various geo-environmental features were constructed using Geography Information System. Finally, spatial statistical analysis and general linear regression were used to analyze the spatial distribution of vectors in relation to the geo-environmental features correlating with the abundance of mosquitoes in pigsties. As the results show, the distribution of mosquitoes in pigsties was not spatially autocorrelated, and several geo-environmental features that were either positively or negatively correlated with mosquito abundance in pigsties were identified. The application of these results to improve the control of vectors of Japanese B Encephalitis is also discussed.

The evolution of topological magnetic domains microscopically correlates the dynamic behavior of memory units in spintronic application. Nanometric bubbles with variation of spin configurations have been directly observed in a centrosymmetric hexagonal magnet (Mn0.5Ni0.5)65(Ga1-yYy)35 (y = 0.01) using Lorentz transmission electron microscopy. Magnetic bubbles instead of biskyrmions are generated due to the enhancement of quality factor Q caused by the substitution of rare-earth element Y. Furthermore, the bubble density and diversified spin configurations are systematically manipulated via combining the electric current with perpendicular magnetic fields. The magnetic bubble lattice at zero field is achieved after the optimized manipulation.

The influence of interstitial hydrogen or carbon on the crystal structure of LaFe11.5Si1.5H delta (delta=0, 1.2, and 2) and LaFe11.5Si1.5C delta (delta=0, 0.1, 0.2, 0.3, 0.4, and 0.5) has been investigated based on the Rietveld analyses of powder X-ray diffraction spectra. Effects of Ce substitution for La are also studied for comparison. The incorporation of interstitial atoms causes a lattice expansion of the compounds while leaves the structural symmetry unchanged. Accompanying the lattice expansion, Fe-Fe bond exhibits a concomitant variation. Four of the five Fe-Fe bonds show a tendency to expansion. The largest elongation occurs for the shortest inter-cluster bond, and the relative change is as large as similar to 2.53% as delta increases from 0 to 2 for LaFe11.5Si1.5H delta. In contrast, the longest Fe-Fe bond shrinks considerably (-0.97%). Similarly effects on Fe-Fe bonds are produced by the paramagnetic to ferromagnetic transition, though the bond variation is smaller. Increase in Ce content produces, fascinatingly, essentially the same effects as the decrease of interstitial content, though Ce occupies different crystallographic sites than those occupied by interstitial atoms. Influence of interstitial atoms on magnetic behaviors may be dominated by the change of the shortest Fe-Fe bond. (C) 2011 Elsevier B. V. All rights reserved.

Coercivity temperature coefficient (β) of the permanent magnet depends on its intrinsic magnetic properties and microstructure. In this paper, the relationship between β and the temperature stabilities of magnetocrystalline anisotropy field (H a ) and saturation magnetization (M s ) as well as the microstructure is discussed. Regarding two concerned microstructural factors: grain size and grain boundary, coercivity thermal-stabilities of MM13.5Fe79.5B7 (MM-mischmetal: unseparated La-Ce-Pr-Nd alloy) and MMxFe94−xB6 (x = 12, 13, 14, 15, 16, 19) melt-spun ribbons, respectively, are investigated. High β values near the theoretical limit are obtained either by decreasing grain size or by reducing MM percentage. In addition, coercivities above room temperature of MM13.5Fe79.5−yCoyB7 (y = 0, 3, 6, 9, 12, 15) melt-spun ribbons are measured. The detailed influences of Co substitutions on β are analyzed, and the weak temperature dependence of M s is proved to the reason for the observed decrease of β. These findings suggest that proper strategy to minimize local stray fields is the key to enhance coercivity thermal-stability of 2:14:1 structure magnet.

The hard magnetic (La,Ce)Co5 nanoflakes with high coercivity and narrow thickness distribution have been successfully obtained by surfactant-assisted ball milling (SABM). The magnetic properties, morphology and interaction of (La,Ce)Co5 nanoflakes are studied in this work. The coercivity and remanence ratio of (La,Ce)Co5 nanoflakes are 5.48 kOe and 0.71, respectively. The X-ray powder diffraction (XRD) patterns indicate that the (La,Ce)Co5 nanoflakes are CaCu5-type hexagonal crystal structure. The average thickness and aspect ratio are 47 nm and 40, respectively. The intergrain interaction of the (La,Ce)Co5 nanoflakes is studied using the δm(H)-curves technique which shows the magnetostatic-dominated particle interaction. The high coercivity and narrow thickness distribution of (La,Ce)Co5 nanoflakes could be promising for the future development of the high performance soft/hard exchange spring magnets.

Using 3D micromagnetics package OOMMF, the ground states of Ce2Fe14B amorphous nanodisks with different dimensions, initial magnetization states and magnetocrystalline anisotropy constants (K) in zero external field were investigated. The simulations indicate that the disk size is the decisive factor in determining magnetic configurations. A diagram is constructed to bring out the dependence of the different equilibrium states on the disk thickness and diameter. When the ratio of thickness (T) to diameter (D) is smaller than 1, the vortex state is energetically more favorable than other states and the eigenfrequency of vortex approximately proportional to (T/D)1/2. A variety of magnetization distributions of ground states for different anisotropy strengths is obtained. The result shows the magnetocrystalline anisotropy not only shrinks or broadens the vortex core but also induces an out-of-plane magnetization component both at the edge and the center of disks. When the K strength reaches a threshold value, there is a transition from vortex state to Bloch-type Skyrmion state which suggests the possibility of Skyrmion in rare-earth materials. In addition, in the system with specific aspect ratio and low intrinsic anisotropy, the vortex domain can always be sustained under various initial conditions. Meanwhile, the existence of stable vortex domain is found by experimentation in amorphous Ce-Fe-B ribbons which is in good agreement with the simulation result.

Orthorhombic CeNiSi2-type polycrystalline RNiSi2 (R=Gd, Dy, Ho, Er, Tm) compounds were synthesized and the magnetic and magnetocaloric properties were investigated in detail. The transition temperatures of RNiSi2 compounds are all in a very low temperature range (

Aims: To evaluate the protective effect of berberine on β-cell lipoapoptosis induced by palmitate and to explore the possible underlying mechanisms. Materials and methods: HIT-T15 pancreatic β-cells were divided into the following treatment groups: untreated controls; 100 μM berberine; 0.5 mM palmitate; 0.5 mM palmitate + 0.1 μM berberine; 0.5 mM palmitate + 1 μM berberine; 0.5 mM palmitate + 10 μM berberine; and 0.5 mM palmitate + 100 μM berberine. After 48 h, cell apoptosis was assessed by flow cytometry and the Hoechst 33258 fluorescent assay. Basal and glucose-stimulated insulin levels in culture medium were measured by radioimmunoassay. Peroxisome proliferator-activated receptor-γ (PPAR-γ) mRNA and protein levels were determined by real-time PCR and immunocytochemistry, respectively. Results: Apoptosis was significantly increased upon treatment with palmitate as compared to the untreated controls (p

In NaZn13-type PrzLa1-z(Fe1-yCoy)(11.8)Si-1.2 (0.07 < y < 0.09. z = 0-0.4) compound, besides adjusting the phase transition temperature to room temperature after the substitutions of Pr for La and Co for Fe, the character of magnetic first-order phase transition is strongly reduced. Thus, the hysteresis losses hardly exist in these compounds. Meanwhile, a large magnetic entropy change about 13.6-15.7J/(kg K), superior to that of Gd, is obtained in 0-5 T field change. So, these compounds are Suitable candidates for magnetic refrigerant near room temperature. (C) 2008 Elsevier Ltd. All rights reserved.

For the Nd0.1La0.9Fe11.5Al1.5 compound, the fine structure of the magnetic transition from the ferromagnetic (FM) to the antiferromagnetic (AFM) states has been studied carefully by means of magnetization ( M ) and heat capacity ( C p ) measurements. Although a single phase with the cubic NaZn13-type structure (Fm3c) has been proved by the room temperature X-ray diffraction pattern, the phase transition has been clearly found to be a stepwise process in M ( T ) and C p ( T ) curves under proper fields. Due to the strong competition between the FM order and AFM order, the characteristic is especially evident under low fields, weakens gradually with the increasing applied field and finally vanishes when the field is higher than 2 T. This multi-step magnetic transition results from the inhomogeneity of the sample, probably due to the inhomogeneous distribution of Nd atoms.

A field survey was conducted in the summer of 2003 and 2004 to evaluate resistance to deltamethrin on house flies, Musca domestica, from 17 urban garbage dumps in the cities of Beijing, Tianjin, and Zhangjiakou. Bioassays were carried out by topical application with technical deltamethrin to measure the levels of resistance to deltamethrin. Tests for synergism with piperonyl butoxide (PBO) were used to study the occurrence of metabolic resistance mechanisms. Competitive polymerase chain reaction (PCR) amplification of specific allele (cPASA) assay was used on individual house flies from these field populations to detect the presence of the kdr and super-kdr alleles associated with pyrethroid resistance. Another PCR followed by labeled allele-specific oligonucleotide hybridization (PCR-ASO) confirmed the presence of the mutation and hence checked the accuracy of cPASA. Deviation of genotype ratios from Hardy-Weinberg equilibrium was tested. Relative to a susceptible laboratory strain, field house ...

Structure, magnetic, and transport properties of the compounds Bi0.5Ca0.5Mn1−xCrxO3 (BCMCO) with 0⩽x⩽0.15 have been experimentally investigated. The substitution of Cr3+ ion for Mn3+ ion suppresses the charge-ordering (CO) state obviously, leading to a gradual reduction of the CO transition temperature (TCO). In contrast, the antiferromagnetic (AF) ordering temperature is essentially unaffected until x=0.024. A spin-glasslike behavior appears above x=0.024 due to the competition between the antiferromagnetic and ferromagnetic correlations. The latter emerges and develops with the incorporation of Cr. The AF phase disappears completely for x⩾0.1, whereas the CO phase is still perceptible for x=0.15. A further analysis indicates that Cr doping produces a similar effect on TCO for the Bi-based and lanthanide-based manganites: TCO decreases at the same rate of ∼8 K for 1% Cr, despite the different initial values of TCO. A striking observation of the present work is that for the manganites, there exists a char...

A three-dimensional finite element model was performed to study the magnetization reversal of (CexNd1-x)2Fe14B nanocomposite permanent magnets. The influences of volume fraction, width and performance parameters of the grain boundary (GB) composition on the coercivity were analyzed by the method of micromagnetic simulation. The calculation results indicate that the structure and chemistry of GB phase play important roles in Nd2Fe14B-based magnets. An abnormal increase in the value of coercivity is found to be connected with the GB phase, approximately when the percentage of doped cerium is between 20% and 30%. While the coercivity decreases directly with the increase in cerium content instead of being abnormal when there is no GB phase in magnets at all or the value of magnetocrystalline anisotropy or exchange integral is too large.

The hard magnetic MMCo5 nanoflakes with high coercivity and narrow size distribution have been successfully obtained by three steps surfactant-assisted ball milling (SABM). The magnetic properties, phase structure and morphology of these MMCo5 nanoflakes were studied in this work. The coercivity and the remanence ratio of MMCo5 nanoflakes reached to 5.89 kOe and 0.75, respectively. The X-ray powder diffraction (XRD) patterns indicated that the MMCo5 nanoflakes were CaCu5-type hexagonal crystal structure. The average thickness, in-plane size and aspect ratio reached to 20 nm, 0.9 μm and 60, respectively. The low cost and great properties of MMCo5 nanoflakes with a centralized thickness distribution could be the building blocks for the future high-performance nanocomposite permanent magnets with an enhanced energy product.

MM14Fe79.9B6.1 magnets were prepared by conventional sintering method. The Curie temperature of the sintered MM2Fe14B magnet was about 210 °C. When the sintering temperature increased from 1010 °C to 1030 °C, the density of the magnet increased from 6.85 g/cm3 to 7.52 g/cm3. After the first stage tempering at 900 °C, the (BH)max and Hcj had a slight increase. The maximum value of (BH)max = 7.6 MGOe and Hcj = 1080 Oe was obtained when sintered at 1010 °C and tempering at 900 °C, respectively. The grain size grew very large when the sintering temperature increased to 1050 °C, and the magnetic properties deteriorated rapidly. La reduced by ∼ 7.5 at. % in grains, which is almost equal to the increased percentage of Nd. That is mainly because La-Fe-B is very difficult to form the 2: 14: 1 phase.

The structural and magnetic characteristics of Er2Co17-based ternaries, in which Co is partly substituted by Ga atoms, have been investigated by means of x-ray powder diffraction (XRPD) and magnetic measurements. XRPD patterns show that all samples are single phase with the rhombohedral Th2Zn17-type structure except the sample with x = 8 which contains a small amount of hcp Co and rare-earth-rich phase as impurity phases. The Ga substitution for Co in these compounds leads to a monotonic increase in unit cell volume and a monotonic decrease in Curie temperature. The saturation magnetization is found to approximately linearly decrease with increasing Ga concentration. For Er2Co17-xGax compounds with x = 4, 5 and 6, compensation points are observed in the corresponding temperature dependence of the magnetization. The values of compensation temperature are found to shift to higher temperature with increasing Ga content. The intersublattice-molecular-field coefficients, n(Er-Co), have been determined on the basis of magnetization curves measured at the compensation temperature. The exchange-coupling constants J(Er-Co) have been calculated by analysing the field dependence of the magnetization and by using the method based on magnetic-ordering temperatures; It has been found that the Ga substitution for Co in these compounds has little influence on Er-Co exchange interaction. XRPD patterns on magnetically aligned samples with x less than or equal to 5 show that the easy magnetization direction at room temperature corresponds to the c-axis.

Magneto-impedance effects have been studied in amorphous and nanocrystalline ribbons. Large magneto-impedance responses have been obtained in nanocrystalline samples by applying a longitudinal DC field, but not in amorphous samples. It was found that the transverse field dependences of the resistance and the reactance of nanocrystalline samples show very broad peaks at relatively high fields (above 35 Oe), while the longitudinal magnetic responses show very sharp peaks at the field of 2 - 7 Oe, sharing some common features with those reported for Co-based amorphous wire and ribbon samples, and can be understood from the same mechanism. It was also found experimentally that the properties of the longitudinal and transverse field dependences of the effective permeability of nanocrystalline samples correlates with those of the impedance, showing a sharp decrease for the longitudinal applied field and a slow decrease for the transverse applied field at a corresponding field value and, the higher the effective permeability, the larger is the magneto-impedance effect at a fixed frequency. and a sensitivity of 20% at a low field (2 Oe) are obtained in this paper.

Magneto-impedance (MI) effects have been observed in amorphous and nanocrystalline Fe73.5CuNb3Si13.5B9 ribbons. Large MI values have been obtained in nanocrystalline samples (NCS), but not in as-quenched samples (AQS). The magnetic responses of impedance of nanocrystalline samples share some common features with that of Co-based amorphous wire and ribbon samples. The field dependencies of effective permeability for nanocrystalline samples have shown a sharp change at the anisotropy field. The effective permeability and the hysteresis loops for AQS and NCS have been shown to be responsible for their MI effects. The sensitivity of the magnetic responses in the nanocrystalline sample can reach 50%/Oe.

The structure, magnetic and magnetotransport properties of La1-xPbxMnO bulk manganese oxides prepared by the standard ceramic techniques were investigated by XRD, VSM, ESM and MR measurements. The sintering condition and the hole doped concentration x have a strong influence on the magnetic properties and magnetoresistance effect. The maximum MR, 20% at room temperature under a field of 2 T, was obtained for x = 0.4 and the sintered temperature Ts = 1260°C. The correlation among the structure, magnetic and MR is discussed.

In the present paper the diffusion behavior of nitrogen in Sm 2 Fe 17 has been investigated. The Curie temperatures of nitrides are experimentally found to vary in a very narrow temperature range. No other intermediate nitride with a small Curie temperature has been found. After the further annealing of non-fully nitrided powder in an Ar atmosphere, some of the nitrogen atoms, which have weak interactions with the interstitial site, can be excited from interstitial sites of Sm 2 Fe 17 molecule by thermal energy and migrate again. However, some of nitrogen atoms are still located at interstitial sites of Sm 2 Fe 17 molecule owing to the strong interaction between gas atoms and the interstitial site. In the nitrogen diffusion process, with increasing occupation of the interstitial site in Sm 2 Fe 17 by nitrogen atoms, the diffuse force for nitrogen atom decreases owing to the change in the chemical potential of system, which results in different diffusive activities of nitrogen atoms under different nitrogen absorption contents x in Sm 2 Fe 17 N x . Meanwhile the particle size dependence of the diffusion behavior has also been discussed. The surface and the grain boundary diffusion modes play important roles in the diffusion process of nitrogen atoms into Sm 2 Fe 17 particles especially for small particles.

Berberine exerts insulin resistance-improving effects, the underlying mechanism of which is not well understood. We herein aimed to examine the effects of berberine on mediators of insulin signaling in pancreatic β- and α- islet cells and hepatocytes using a rat obesity model. Rats were fed the following diets for 22 weeks: normal control (NC); normal+berberine (NC+BBR 200 mg/kg/day); high-fat (HF); HF+BBR(1) (BBR 100 mg/kg/day); HF+BBR(2) (BBR 200 mg/kg/day). Metabolic parameters were assessed and mediators of insulin signaling were quantified by immunohistochemistry. The HF diet significantly increased body weight (BW), visceral fat (VF), the visceral fat to BW ratio (VF/BW), and insulin resistance index in the HF group compared with the NC group. Both doses of BBR significantly reduced HF diet-induced increases in BW, VF, and VF/BW. IR and IRS-1 expression in β-cells was significantly lower in the HF group, but not the HF+BBR groups, compared with the NC and NC+BBR groups. Glucagon expression in α-cells was significantly higher in the HF group compared with all other groups. IR expression in α-cells was significantly lower in the HF group compared with the NC, NC+BBR, and HF+BBR(2) groups. IR expression in hepatocytes was significantly lower in the HF group compared with all groups. Our preliminary findings suggest that berberine may ameliorate the development of insulin resistance by differentially preventing alterations in expression of IR, IRS-1, and glucagon in β-cells, α-cells, and hepatocytes.

Culex pipiens complex mosquitoes are widely distributed throughout China and are known to be important disease vectors. Two pyrethroid resistance associated mutations have been identified in Cx. pipiens complex (Diptera: Culicidae), but there is little information on the diversity and distribution of kdr alleles in pyrethroid resistance in Cx. pipiens complex mosquitoes in China. In the present study, we report on a modified three tube allele-specific (AS)-PCR method for detecting the 1014F and 1014S alleles. The new technique was applied to identify the distribution of the two alleles in natural Cx. pipiens complex populations in China. The results confirmed that the new method is both sensitive and specific. The 1014F allele was found in all 14 of the field populations tested (frequency ranged from 6.8 to 76.2%) and the 1014S allele was found in almost two-thirds (frequency from 2.4 to 28.6%), indicating that the genotypes known to be associated with pyrethroid resistance are widespread in China. The resistance-associated alleles were more common in southern Chinese sampling sites than in northern sites. The coexistence of the two resistant mutations in individual mosquitoes was also observed in five of the field populations. Two alternative mutations within the L1014 codon were identified in Culex pipiens molestus Forskal, 1775, including a non-synonymous mutation resulting in a 1014C substitution.

Magnetic, electronic, and thermal transport properties of ${\mathrm{Eu}}_{0.55}{\mathrm{Sr}}_{0.45}\mathrm{Mn}{\mathrm{O}}_{3}$ have been experimentally studied. The compound is found to exhibit a complex magnetic behavior with the change of temperature and magnetic field. Without magnetic field, it stays in a Griffiths-like state in a wide temperature range above $\ensuremath{\sim}100\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, characterized by the presence of ferromagnetic (FM) clusters of the size of $\ensuremath{\sim}8$ Mn ions, and an antiferromagnetic (AFM) state below $\ensuremath{\sim}100\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, evidenced by thermopower and heat conductivity. FM phase emerges and grows in the AFM matrix with applied field, resulting in a series of phase transitions from the paramagnetic (PM) state first to the AFM state, then to the FM and the AFM states upon cooling $(\ensuremath{\sim}0.8\phantom{\rule{0.3em}{0ex}}\mathrm{T}lHl\ensuremath{\sim}1\phantom{\rule{0.3em}{0ex}}\mathrm{T})$, or a simple PM-FM transition $(Hg\ensuremath{\sim}2.3\phantom{\rule{0.3em}{0ex}}\mathrm{T})$. The AFM state is unstable under high fields, and the high- and low-temperature AFM transitions are depressed by the fields above $\ensuremath{\sim}1$ and $\ensuremath{\sim}2.3\phantom{\rule{0.3em}{0ex}}\mathrm{T}$, respectively. The FM transition is incomplete when the field is below $\ensuremath{\sim}1.5\phantom{\rule{0.3em}{0ex}}\mathrm{T}$, leading to a coexistence of the FM and PM (or AFM) phases in the intermediate temperature range. A spin-glass-like behavior is observed in the AFM background below $\ensuremath{\sim}50\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. Significant response of resistance, thermopower, and heat conduction to magnetic transition, either FM or AFM transition, has been observed. Unlike the typical AFM manganites, for which usually a depression of thermal conduction occurs at the AFM state, the AFM transition in ${\mathrm{Eu}}_{0.55}{\mathrm{Sr}}_{0.45}\mathrm{Mn}{\mathrm{O}}_{3}$ enhances the thermal conduction. From the PM phase to the AFM phase and to the FM phase, thermal conductivity increases monotonically. A remarkable result of the present work is the different behaviors of thermopower and resistivity. The former displays a metallic behavior below a distinct temperature that is significantly lower than the metal-to-insulator transition temperature determined by resistivity. Furthermore, thermopower remains metallic while the resistivity shows up an upturn due to the AFM transition in the low-temperature range under the field of $1.5\phantom{\rule{0.3em}{0ex}}\mathrm{T}$. Based on these data, a magnetic phase diagram is proposed.

Effect of Ti doping on the electrical transport and magnetic properties of layered Na0.8Co1-xTixO2 compounds has been investigated. The lattice parameters a and c increase with x. A minor amount of Ti doping results in a metal-insulator transition at low temperatures. For samples with x > 0.03, the variable-range hopping process dominates the transport behavior above a certain temperature. The temperature dependence of magnetization of all the samples is found to obey the Curie-Weiss law. The mechanism of the doping effect is discussed., 19 pages, 6 figures, Solid State Commun. (in press)

Magnetic granular CoCu alloy ribbons were prepared by the melt‐spun method, and the structural, magnetotransport, magnetic properties, and the effects of annealing on these properties were studied by x‐ray diffraction, vibrating sample magnetometer, and magnetoresistance (MR) measurements at room temperature. Giant magnetoresistance was observed over a broad range of Co concentrations with a maximum MR ratio of 7.8% (at x=0.20 and 500 °C annealing) under a magnetic field of 20 kOe at room temperature. It is found that the relationship between MR and magnetic field H depended strongly on the annealing temperature and a linear MR‐H relation could be obtained at an optimum annealing condition. The MR ratio did not depend on the direction between H and electric current I. These features are very suitable for making isotropic magnetic field transducers.