Magnetization reversal and magnetic interactions in anisotropic Nd-Dy-Fe-Co-B/MgO/α-Fe disks and multilayers

We report on a field induced domain evolutionary procedure in the anisotropic Nd-Dy-Fe-Co-B/MgO/Fe multilayers by using first-order-reversal-curves and magnetic force microscopy. Different reversal behaviors and domain sizes are found in well coupled and decoupled multilayers by changing the thickness of the spacer layer. The competition between dipolar magnetostatic energy and Zeeman energy is evaluated by in-field observation throughout nucleation and annihilation processes. In addition, lithography-patterned arrays of soft Fe disks onto a continuous Nd-Dy-Fe-Co-B hard-magnetic layer are designed. By decreasing the applied field, it is found that magnetization orientations of the Fe disk and Nd-Dy-Fe-Co-B layer are aligned parallel. In the decoupled disk, although the out-of-plane magnetization orientations are observed, the orientation of the domains in the Fe disk is random. Furthermore, it is found that a stronger anisotropy of the Nd-Dy-Fe-Co-B layer decreases the interaction length. Our results provide a new understanding of anisotropic nanocomposite magnets with long-ranged magnetic interactions.

[Modified capsular arthroplasty for young patients with developmental dislocation of the hip]

Developmental dislocation of the hip(DDH) is one of the most serious hip diseases. Patients with unilateral DDH are prone to secondary osteoarthritis, low back pain, gait disturbance and compensatory scoliosis because of the leg length discrepancy. Total hip arthroplasty(THA) is the highly effective treatment for patients with hip pain or dysfunction caused by unilateral DDH, thus decrease the demand for hip-preserving surgeries such as capsular arthroplasty which may postpone or avoid hip replacement. However, the failure rate of THA for young patients is high and the majority of young patients may require one or more revision arthroplasties throughout their lifetime. The basic principle of capsular arthroplasty is that the femoral head wrapped by capsule is placed into a newly reamed socket on the location of true acetabulum. Therefore, hip replacement for patients with previous capsular arthroplasty becomes easier and safer than primary THA. However, the early capsular arthroplasty have been abandoned due to the relatively high rates of femoral head necrosis and hip stiffness. Ganz modified the early procedure with the technique of surgical hip dislocation in 2012, and emphasized the importance of postoperative rehabilitation. The incidence of complication, therefore, decreased greatly due to the preservation of main blood supply of femoral head as well as the proper postoperative management. In order to improve the clinical outcomes of this modified procedure, the selection of indications and surgeons' experience should also be taken into consideration.

[Novel biomarkers for latent tuberculosis infection by plasma proteomic profiling]

OBJECTIVE

To screen specific biomarkers for latent tuberculosis infection by comparing the plasma proteomic profiling between latent tuberculosis infection and healthy controls.

METHODS

The plasma proteins from 15 cases with latent tuberculosis infection and 15 healthy controls were detected by the label-free quantitative proteomic technology. Differential expressed proteins were analyzed by GO, KEGG, and BiNGO analysis. Student's t test was used to analyze the differential expression between 2 groups.

RESULTS

Twenty-three candidate proteins were identified, among which 15 proteins were downregulated (<0.5-fold at P<0.05) and 8 proteins were upregulated (>2.0-fold at P<0.05) in the latent tuberculosis infection group. Bioinformatic analysis revealed 3 proteins AAT, C3 and C4A to be the most significant.

CONCLUSION

There were differential plasma protein profiles between latent tuberculosis infection and healthy controls. Candidate proteins AAT, C3 and C4A were promising biomarkers for discriminating cases with latent tuberculosis infection from healthy persons.

Valence-band offset and forward-backward charge transfer in manganite/NiO and manganite/LaNiO3 heterostructures

The valence-band offset (VBO) of the La(0.67)Sr(0.33)MnO(3)/NiO (LSMO/NiO), LaMnO(3)/NiO (LMO/NiO), LSMO/LaNiO(3) (LSMO/LNO) and LMO/LaNiO(3) (LSMO/LNO) heterostructures has been investigated using X-ray photoemission spectroscopy. The VBO values are calculated to be -0.72, -0.05, +1.43 and +1.51 eV for the LSMO/NiO, LSMO/LNO, LMO/LNO and LMO/NiO heterostructures, respectively. Hence, when compared with NiO and LNO, the valence band of LSMO is shifted to a lower binding energy, whereas that of LMO is shifted to a higher binding energy. In addition, the charge transfer at the interfaces has been depicted as Mn(3.3+) + 0.7e→ Mn(2.6+), Mn(3.3+) + 0.1e→ Mn(3.2+), Mn(3.0+)- 0.4e→ Mn(3.4+) and Mn(3.0+)- 0.5e→ Mn(3.5+) for the LSMO/NiO, LSMO/LNO, LMO/LNO and LMO/NiO heterostructures, respectively. Thus, the charge transfer procedure can be described as electron hopping from NiO and LNO to LSMO in the LSMO/NiO and LSMO/LNO heterostructures, and electron hopping from LMO to NiO and LNO in the LMO/NiO and LSMO/LNO heterostructures. Therefore, the charge transfer is dependent on the VBO, and the charge transfer direction can be determined from the negative or positive values of the VBO.

CoxNi100-x nanoparticles encapsulated by curved graphite layers: controlled in situ metal-catalytic preparation and broadband microwave absorption

We report a one-step approach for preparing dispersive CoxNi100-x nanoparticles completely encapsulated by curved graphite layers. The nanoparticles were prepared by evaporating Co-Ni alloys and the shell of graphite layers was formed by in situ metal-catalytic growth on the surface of nanoparticles whose layer number was controlled by tuning the Co content of the alloys. By modulating the composition of the magnetic core and the layer number of the shell, the magnetic and dielectric properties of these core/shell structures are simultaneously optimized and their permeability and permittivity were improved to obtain the enhanced electromagnetic match. As a result, the bandwidth of reflection loss (RL) exceeding -20 dB (99% absorption) of the nanocapsules is 9.6 GHz for S1, 12.8 GHz for S2, 13.5 GHz for S3 and 14.2 GHz for S4. The optimal RL value reaches -53 dB at 13.2 GHz for an absorber thickness of 2.55 mm. An optimized impedance match by controlling the growth of the core and shell is responsible for this extraordinary microwave absorption.

Monopole excitations of a harmonically trapped one-dimensional Bose gas from the ideal gas to the Tonks-Girardeau regime

Using a time-dependent modified nonlinear Schrödinger equation (MNLSE)-where the conventional chemical potential proportional to the density is replaced by the one inferred from Lieb-Liniger's exact solution-we study frequencies of the collective monopole excitations of a one-dimensional Bose gas. We find that our method accurately reproduces the results of a recent experimental study [E. Haller et al., Science 325, 1224 (2009)] in the full spectrum of interaction regimes from the ideal gas, through the mean-field regime, through the mean-field Thomas-Fermi regime, all the way to the Tonks-Giradeau gas. While the former two are accessible by the standard time-dependent NLSE and inaccessible by the time-dependent local density approximation, the situation reverses in the latter case. However, the MNLSE is shown to treat all these regimes within a single numerical method.

Tailoring the magnetic anisotropy of Py/Ni bilayer films using well aligned atomic steps on Cu(001)

Tailoring the spin orientation at the atomic scale has been a key task in spintronics technology. While controlling the out-of-plane to in-plane spin orientation has been achieved by a precise control of the perpendicular magnetic anisotropy at atomic layer thickness level, a design and control of the in-plane magnetic anisotropy has not yet been well developed. On well aligned atomic steps of a 6° vicinal Cu(001) surface with steps parallel to the [110] axis, we grow Py/Ni overlayer films epitaxially to permit a systematic exploration of the step-induced in-plane magnetic anisotropy as a function of both the Py and the Ni film thicknesses. We found that the atomic steps from the vicinal Cu(001) induce an in-plane uniaxial magnetic anisotropy that favors both Py and Ni magnetizations perpendicular to the steps, opposite to the behavior of Co on vicinal Cu(001). In addition, thickness-dependent study shows that the Ni films exhibit different magnetic anisotropy below and above ~6 ML Ni thickness.

Annexin A2 is implicated in multi-drug-resistance in gastric cancer through p38MAPK and AKT pathway

Studies have shown that Annexin A2 (ANXA2) is related with tumor proliferation, apoptosis, differentiation, invasion, migration, and drug resistance. The purpose of this study was to investigate the role and its mechanisms of ANXA2 in multi-drug-resistance (MDR) in gastric cancer. ANXA2 expression in both gastric cancer tissues and cell lines were detected by quantitative real-time PCR (RT-qPCR) and Western blotting. The cell proliferation was measured by SRB assay. The pool of siRNA against ANXA2 was designed and synthesized and then transfected into resistant gastric cancer SGC7901/DDP cells. ANXA2 expression was detected by RT-qPCR and Western blotting. Drug sensitivities of SGC7901/DDP cells to P-gp-related drug (doxorubicin) and P-gp-non-related drugs (5-FU and cisplatin) were measured by SRB assay. Expression of MDR-related genes and phosphorylation of AKT and MAPKs were also detected by RT-qPCR and Western blotting. Results showed that ANXA2 expression was significantly higher in gastric specimens than that in normal tissues, and negatively correlated with the differentiation level of gastric cancer. In addition, ANXA2 expression level was higher in SGC7901/DDP cells than that in parent SGC7901 cells. After knock-down ANXA2 expression using ANXA2 small interfering RNA, the drug sensitivity of SGC7901/DDP cells to doxorubicin, 5-FU and DDP increased. Delivery of ANXA2 siRNA significantly downregulated the expression of P-gp, MRP1 and Bcl-2, while markedly upregulated Bax in SGC7901/DDP cells. However, several other MDR factors such as GST-π, TOPO-I and TOPO-II had no obvious changes. Additionally, phosphorylation of P38MAPK and AKT, but not ERK1/2 or JNKs was specifically decreased in SGC7901/DDP cells after ANXA2 siRNA delivery. Importantly, P38MAPK and AKT inhibitor increased the drug sensitivity of SGC701/DDP cells in a similar way as ANXA2 siRNAs does. ANXA2 is involved in gastric cancer MDR through regulating p38MAPK and AKT pathways as well as certain MDR factors.

Granularity controlled nonsaturating linear magnetoresistance in topological insulator Bi2Te3 films

We report on the magnetotransport properties of chemical vapor deposition grown films of interconnected Bi2Te3 nanoplates. Similar to many other topological insulator (TI) materials, these granular Bi2Te3 films exhibit a linear magnetoresistance (LMR) effect which has received much recent attention. Studying samples with different degree of granularity, we find a universal correlation between the magnitude of the LMR and the average mobility (⟨μ⟩) of the films over nearly 2 orders of magnitude change of ⟨μ⟩. The granularity controlled LMR effect here is attributed to the mobility fluctuation induced classical LMR according to the Parish-Littlewood theory. These findings have implications to both the fundamental understanding and magnetoresistive device applications of TI and small bandgap semiconductor materials.

Meta-analysis demonstrates lack of association of the hOGG1 Ser326Cys polymorphism with bladder cancer risk

The functional polymorphism Ser326Cys (rs1052133) in the human 8-oxoguanine DNA glycosylase (hOGG1) gene has been implicated in bladder cancer risk. However, reports of this association between the Ser326Cys polymorphism and bladder cancer risk are conflicting. In order to help clarify this relationship, we made a meta-analysis of seven case-control studies, summing 2521 cases and 2408 controls. We used odds ratios (ORs) with 95% confidence intervals (95%CIs) to assess the strength of the association. Overall, no significant association between the hOGG1 Ser326Cys polymorphism and bladder cancer risk was found for Cys/Cys vs Ser/Ser (OR = 1.10, 95%CI = 0.74-1.65), Ser/Cys vs Ser/Ser (OR = 1.07, 95%CI = 0.81-1.42), Cys/Cys + Ser/Cys vs Ser/Ser (OR = 1.08, 95%CI = 0.87-1.33), and Cys/Cys vs Ser/Cys + Ser/Ser (OR = 1.04, 95%CI = 0.65-1.69). Even when stratified by ethnicity, no significant association was observed. We concluded that the hOGG1 Ser326Cys polymorphism does not contribute to susceptibility to bladder cancer.

High dielectric loss in graphite-coated Ti nanocapsules

Graphite-coated Ti nanocapsules, with Ti nanoparticles as core and onion-like graphite layers as shell, have been prepared by a modified arc-discharge method in ethanol atmosphere, and characterized by means of X-ray diffraction, transmission electron microscopy and Raman spectroscopy. The dielectric properties of the graphite-coated Ti nanocapsules have been investigated in the 2-18 GHz range. An equivalent circuit model was used to interpret the non-linear dielectric resonance behavior of the graphite-coated Ti nanocapsules. The high dielectric loss is mainly attributed to conductance loss and dipole-relaxation loss in the graphite-coated Ti nanocapsules. The graphite-coated Ti nanocapsules exhibit promising properties for application as a new type of shield or absorbent of electromagnetic waves.

ELAC2 polymorphisms and prostate cancer risk: a meta-analysis based on 18 case-control studies

Polymorphisms in the elaC homolog-2 (ELAC2)/HPC2 gene have been hypothesized to alter the risk of prostate cancer. However, the results of the related published studies remained conflicting. We performed a meta-analysis of 18 studies evaluating the association between ELAC2 Ser217Leu and Ala541Thr polymorphisms and prostate cancer risk. Overall, ELAC2 Leu217 allele was associated with increased prostate cancer risk as compared with the Ser217 allele (odds ratio (OR)=1.13, 95% confidence interval (CI): 1.03–1.24, P=0.019 for heterogeneity), as well as in the heterozygote comparison (OR=1.21, 95% CI: 1.07–1.36, P=0.034 for heterogeneity) and the dominant genetic model (OR=1.20, 95% CI: 1.07–1.35, P=0.025 for heterogeneity). Furthermore, the ELAC2 Thr541 allele was associated with increased prostate cancer risk as compared with the Ala541 allele (OR=1.22, 95% CI: 1.00–0.48, P=0.131 for heterogeneity). In the stratified analyses for Ser217Leu polymorphism, there was significantly increased prostate cancer risk in Asian and Caucasian populations, and studies using sporadic and familial prostate cancer cases. Similar result was found in the Asian population in the stratified analyses for Ala541Thr polymorphism. This meta-analysis showed evidence that ELAC2 Ser217Leu and Ala541Thr polymorphisms were associated with prostate cancer risk, and might be low-penetrance susceptibility markers of prostate cancer.

The Linear Thermal Expansion of Bulk Nanocrystalline Ingot Iron from Liquid Nitrogen to 300 K

The linear thermal expansions (LTE) of bulk nanocrystalline ingot iron (BNII) at six directions on rolling plane and conventional polycrystalline ingot iron (CPII) at one direction were measured from liquid nitrogen temperature to 300 K. Although the volume fraction of grain boundary and residual strain of BNII are larger than those of CPII, LTE of BNII at the six measurement directions were less than those of CPII. This phenomenon could be explained with Morse potential function and the crystalline structure of metals. Our LTE results ruled out that the grain boundary and residual strain of BNII did much contribution to its thermal expansion. The higher interaction potential energy of atoms, the less partial derivative of interaction potential energy with respect to temperature T and the porosity free at the grain boundary of BNII resulted in less LTE in comparison with CPII from liquid nitrogen temperature to 300 K. The higher LTE of many bulk nanocrystalline materials resulted from the porosity at their grain boundaries. However, many authors attributed the higher LTE of many nanocrystalline metal materials to their higher volume fraction of grain boundaries.

The Electrochemical Corrosion of Bulk Nanocrystalline Ingot Iron in Acidic Sulfate Solution

The corrosion properties of bulk nanocrystalline ingot iron (BNII) fabricated from conventional polycrystalline ingot iron (CPII) by severe rolling were investigated by means of immersion test, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS) tests, and scanning electron microscopy (SEM) observation. These experimental results indicate that BNII possesses excellent corrosion resistance in comparison with CPII in acidic sulfate solution at room temperature. It may mainly result from different surface microstructures between CPII and BNII. However, the corrosion resistance of nanocrystalline materials is usually degraded because of their metastable microstructure nature, and the residual stress in nanocrystalline materials also can result in degradation of corrosion resistance according to the traditional point of view.

Dynamics of a bright soliton in Bose-Einstein condensates with time-dependent atomic scattering length in an expulsive parabolic potential

We present a family of exact solutions of the one-dimensional nonlinear Schro dinger equation which describes the dynamics of a bright soliton in Bose-Einstein condensates with the time-dependent interatomic interaction in an expulsive parabolic potential. Our results show that, under a safe range of parameters, the bright soliton can be compressed into very high local matter densities by increasing the absolute value of the atomic scattering length, which can provide an experimental tool for investigating the range of validity of the one-dimensional Gross-Pitaevskii equation. We also find that the number of atoms in the bright soliton keeps dynamic stability: a time-periodic atomic exchange is formed between the bright soliton and the background.

Preparation and Electrochemical Corrosion Behavior of Bulk Nanocrystalline Ingot Iron in HCl Acid Solution

Bulk nanocrystalline ingot iron (BNII) was produced by the severe rolling technique. The corrosion behaviors of BNII and as-received conventional polycrystalline ingot iron (CPII) in 1 M HCl solution were investigated by potentiodynamic polarization tests, electrochemical impedance spectroscopy measurement, and immersion tests at room temperature. For BNII, the anodic dissolution process is inhibited, but the cathodic process is enhanced. The corrosion current and average corrosion rate of BNII are 0.479 and 0.391 those of CPII, respectively. The resistance of the charge transfer of BNII is about 1.59 times higher than that of CPII. These results indicate that the corrosion resistance of BNII is improved in comparison with CPII.

The effects of gamma interferon on replication of foot-and-mouth disease virus in persistently infected bovine cells

Foot-and-mouth disease virus (FMDV) causes a highly contagious viral disease of cloven-hoofed animals, which has a considerable socio-economic impact on the countries affected. In addition, persistent infection can occur following clinical or sub-clinical disease in either vaccinated or non-vaccinated cattle. The mechanism(s) by which FMDV persistence is established and maintained is not fully understood. To better understand the basic mechanisms controlling the virus infection in cattle, the effects of interferon gamma (IFN-gamma) on the replication of FMDV was evaluated in vitro in persistently infected-epithelial cells isolated from FMDV infected cattle. Initially primary bovine thyroid (BTY) cells were treated with varying doses of bovine recombinant IFN-gamma. The cytokine activity was measured by detection of viral antigen in cell supernatants and viral RNA expression compared with cells without INF-gamma treatment. Pretreatment with IFN-gamma profoundly affected FMDV growth in BTY cells. The replication of FMDV was affected in the presence of more than 2.5 u/ml of IFN-gamma and the effect was both dose-dependent and related to the time of exposure. Analysis of the mechanism of inhibition suggests that IFN-gamma did not inhibit the viral replication through induction of nitric oxide. More interesting is the finding that continuous treatment with IFN-gamma severely restricts FMDV replication or even cures persistently infected bovine epithelial cells, indicating that a cytokine-mediated pathway may be involved in the in vivo clearance of persistent FMDV.

The vasorelaxation of cerebral arteries by carbon monoxide

Carbon monoxide (CO) is known to increase cerebral blood flow, but the effect of CO on the vascular tone of large cerebral arteries is uncertain. We tested whether CO affects cerebral artery tone by measuring tension generated by ex vivo segments of dog basilar artery upon exposure to CO. In cerebral artery segments contracted with either KCl or prostaglandin F(2alpha), CO caused a concentration-related relaxation beginning with a concentration of 57 microM. Relaxation did not occur if CO was administered in the presence of bubbling carboxygen (95% O(2):5% CO(2)), which reduces greater than 99% of CO from the solution. Furthermore, the CO-induced relaxation of cerebral artery segments was reduced in the presence of the guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 10 microM)or the potassium channel blocker tetraethylammonium (TEA, 1 mM). Neither ODQ nor TEA completely eliminated the relaxation caused by CO and there was no additive effect if ODQ and TEA were administered together. These results suggest that cerebral arteries are directly relaxed by CO and that this relaxation depends upon the activation of guanylyl cyclase and the opening of potassium channels.

Vasospasm in monkeys resolves because of loss of and encasement of subarachnoid blood clot

BACKGROUND AND PURPOSE

We studied in monkeys why vasospasm resolves after subarachnoid hemorrhage (SAH).

METHODS

Monkeys underwent angiography and right (n=17) or bilateral (n=8) SAH. Animals with bilateral SAH underwent angiography 1, 3, 5, and 7 days later. Animals with right SAH underwent angiography 7 days later. The clot was then not removed (n=5), removed and replaced with fresh clot (n=7), or removed and not replaced (n=5). At the same time on day 7, the removed clot (n=12) or fresh clot (n=5) was placed on the left side. Angiography was repeated every 2 days until day 14.

RESULTS

SAH caused significant vasospasm on day 7 that resolved by day 14. Removal of clot on day 7 resulted in more rapid resolution of vasospasm. Placement of fresh clot onto arteries that had already been exposed to clot for 7 days produced vasospasm that persisted without resolving for an additional 7 days. Placement of 7-day-old clot from the right onto previously unexposed left arteries or of clot from blood removed from an animal 7 days after SAH caused significantly more rapid onset of vasospasm compared with de novo vasospasm. Microscopic examination of the clots showed they were surrounded by macrophages 7 days after SAH. Arterial compliance and contractility were reduced in relation to duration of the exposure of arteries to clot.

CONCLUSIONS

Vasospasm resolves because of loss of subarachnoid blood clot. We hypothesize that reduced spasmogen release from the clot contributes to resolution of vasospasm. There was no response in the cerebral arteries that rendered them less responsive to the subarachnoid clot.

Synthesis, characterization, and magnetic properties of carbon- and boron-oxide-encapsulated iron nanocapsules

Carbon- and boron-oxide-encapsulated iron nanocapsules have been synthesized by arc discharge in methane (CH4) and diborane (B2H6) atmospheres respectively. The characterization and magnetic properties of carbon- and boron-oxide-encapsulated iron nanocapsules [abbreviated as Fe(C) and Fe(B) respectively] were investigated and compared. The structure of the Fe(B) nanocapsules is different from that of the Fe(C) nanocapsules. The Fe(C) nanocapsules consist of a crystalline graphite shell and a core of alpha-Fe and/or Fe3C. The Fe(B) nanocapsules consist of an amorphous boron-oxide layer and a core of Fe(B) solid solution, alpha-Fe, gamma-Fe, FeB, and/or Fe3B phases. The saturation magnetizations of both the Fe(C) and the Fe(B) nanocapsules below 300 K decrease monotonically with increasing temperature. The coercivities of the Fe(C) and Fe(B) nanocapsules are almost 2 orders of magnitude higher than that of bulk Fe. The temperature dependence of magnetization at high temperatures indicates the existence of some phase transformations.