Superconductor (SC)/ferromagnet (FM) Nb/Co multilayers have been produced by magnetron-sputtering with a 100nm thickness of Nb and 5, 10, and 20nm of Co. The superconducting properties have been ...investigated by electric transport measurements. It was found that the thicker Co layers decrease the superconducting transition temperature (Tc) less than the thinner ones. In order to understand this unexpected behavior, the microstructure of the layers has been investigated by means of Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM) and by energy-dispersive X-ray spectroscopy line scan analyses in scanning TEM (STEM) mode. It was found that the decisive parameter which determines the effect of magnetic layers on Tc of the superconducting layers is not only the roughness (R), but the ratio of the roughness to thickness (dCo) of the magnetic Co layer, δ=R/dCo. For δ>1 the magnetic stray field of the magnetic layers is the main reason for the Tc reduction.
•Multilayers of Nb/Co, with controlled thickness, have been prepared.•Thicker Co samples have higher superconducting transition temperature.•Roughness of the surface and interfaces has been studied.•The ratio of roughness to thickness of Co layers determines Tc.
Confronting reports of room temperature ferromagnetic ordering in bulk as well as thin films of dilute doped semiconductors motivated us to prepare and study some dilute Mn-doped (2% and 4%) ZnO ...polycrystalline pellets. Our aim was to find out how the changes in the electronic structure can correlate to the observed magnetic properties in such diluted magnetic semiconductor materials. The 2% Mn sample shows above room temperature magnetic ordering with further enhancement in magnetic properties upon cooling. The magnetic ordering gets completely quenched for 4% Mn doping at room temperature and no evidence of ordering found even down to 5K. The electronic structure of these two samples has been investigated using Mn L23 X-ray absorption spectroscopy, Zn 2p and 3p, Mn 3p and O 1s X-ray photoemission spectroscopy. Our results show that overall the manganese shifts toward the higher valence state upon Mn doping while there is no change in the zinc and oxygen valence. The concentration of divalent Mn state is found to be much higher in the ferromagnetic sample (Mn=2%). For the non-ferromagnetic sample a larger contribution of higher oxidation Mn states is present and also the oxygen content is found to be higher. These two factors have been correlated to the suppressed ferromagnetism but it is difficult to predict their relative weights.
Cancer metastasis can occur at the early stage of tumor development when a primary tumor is at the microscopic size. In particular, the interaction of malignant cells with other cell types including ...cancer-associated fibroblasts (CAF) in promoting metastasis at the early stage of tumor development remains largely unknown. Here, we investigated the role of CAFs in facilitating the initial events of cancer metastasis when primary tumors were at microscopic sizes.
Multicolor-coded cancer cells and CAFs were coimplanted into the transparent zebrafish body and metastasis at a single-cell level was monitored in living animals. Healthy fibroblasts, tumor factor-educated fibroblasts, and CAFs isolated from various tumors were tested for their ability to facilitate metastasis.
We showed that CAFs promoted cancer cell metastasis at the very early stage during primary tumor development. When a primary tumor was at the microscopic size consisting of a few hundred cells, CAFs were able to hijack cancer cells for dissemination from the primary site. Surprisingly, a majority of metastatic cancer cells remained in tight association with CAFs in the circulation. Furthermore, stimulation of non-metastasis-promoting normal fibroblasts with TGF-B, FGF-2, HGF, and PDGF-BB led to acquisition of their metastatic capacity.
Cancer metastasis occurs at the very early stage of tumor formation consisting of only a few hundred cells. CAFs are the key cellular determinant for metastasis. Our findings provide novel mechanistic insights on CAFs in promoting cancer metastasis and targeting CAFs for cancer therapy should be aimed at the early stage during cancer development.
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► IL6 has been implicated in pathogenesis of cerebral palsy and showed gender difference. ► Two SNPs of IL6 are associated with spastic tetraplegia in males. ► Genetic factors play an important role ...in cerebral palsy predisposition.
Cerebral palsy (CP) is a group of non-progressive motor impairment and permanent disorders causing limitation of activity and abnormal posture. It may be caused by infection (such as chorioamnionitis), asphyxia or multiple genetic factors. The Interleukin 6 gene (IL6) was suggested to be involved in the susceptibilities to CP risk as a kind of proinflammatory cytokine.
To explore the genetic association between the polymorphisms of the IL6 gene and CP in the Chinese population.
A total of 542 CP patients and 483 healthy control children were recruited in this study to detect five single nucleotide polymorphisms (rs1800796, rs2069837, rs2066992, rs2069840, and rs10242595) in the IL6 locus. Genotyping of SNPs was performed by the MassArray platform-based genotyping approach. The SHEsis program was applied to analyze the genotyping data.
Of the five selected SNPs, no significant allelic and genotypic association was found between CP patients and controls. However, subgroup analysis found significant differences in allele frequencies between spastic tetraplegia in males compared with controls at rs1800796 (OR=1.39, P=0.033, P=0.099 after SNPSpD correction) and rs2069837 (OR=1.58, P=0.012, P=0.035 after SNPSpD correction). The frequencies of the C allele of rs1800796 and the A allele of rs2069837 were greater in males with spastic tetraplegia than in the controls. The two SNPs haplotype rs1800796 (G) – rs2069837 (G) were also associated with a decreased risk of spastic tetraplegia in males (OR=0.619, P=0.009, P=0.027 after Bonferroni correction).
Genetic variation of the IL6 gene may influence susceptibility to spastic tetraplegia in males and its role in cerebral palsy deserves further evaluation in a large-scale and well-designed study.
The evolution of reversible room temperature ferromagnetism (RTFM) has been investigated in Co- and Fe-doped (5% each) and non-doped CeO
2
polycrystalline samples. Specimens with different oxygen ...vacancy (V
O
) concentration including the (i) as-synthesized, (ii) hydrogenated and (iii) re-annealed in air were investigated using SQUID magnetometry, x-ray diffraction and x-ray photoelectron spectroscopy. The influence of the electronic properties on the RTFM was examined/analysed systematically. Our findings confirm that the ferromagnetism observed in CeO
2
originates due to the oxygen vacancies, supporting the V
O
mediated ferromagnetic exchange mechanism. Additionally, the cationic (cerium and transition metal) valence states play a crucial role.
The interfacial magnetism of NiO/NiFe bilayers with different NiFe layer thicknesses, produced by DC and RF magnetron sputtering, has been studied by magnetometry and X-ray magnetic circular ...dichroism (XMCD). In magnetic hysteresis loops, the exchange bias field was found to be inversely proportional to the NiFe layer thickness. The fit using the Meiklejohn and Bean model gives a coupling energy at the NiO/NiFe interface of approximately 0.027
mJ/m
2. The analysis of the XMCD spectra of Fe and Ni, using the sum rules, shows a reduction of the effective spin magnetic moments in bilayers with NiFe thickness less than 4
nm. This reduction is attributed to hybridization of ferromagnetic and antiferromagnetic atoms
d orbitals near the interface and/or formation of antiferromagnetic alloys due to atomic diffusion at the interfaces.
The metal magnetic memory (MMM) technique is hardly capable of evaluating early damage quantitatively owing to the lack of a rigorous and self-consistent theoretical model. Taking into account that ...previous magnetic models focus mainly on magnetic signal variation with stress, in this
paper a linear magnetic dipole model has been developed to represent the self-magnetic leakage field distribution due to stress concentration in a V-notched plate. The magnetic charge density distribution is assumed to be identical to the dislocation density distribution in the plastic zone
at a crack tip. Simulation and analysis show that both the normal and tangential components of MMM signals can capture basic characteristics regarding the early damage obtained in experiments, and it is also shown that the MMM signals in the stress concentration zone decrease obviously with
increasing lift-off values, indicating that the proposed model can provide a quantitative prediction of the degree of damage and range, respectively.
Chronic obstructive pulmonary disease (COPD) is a common disease that severely threatens human health. Acute exacerbation of COPD (AECOPD) is a major cause of disease progression and death, and ...causes huge medical expenditures. This consensus statement represents a description of clinical features of AECOPD in the People's Republic of China and a set of recommendations. It is intended to provide clinical guidelines for community physicians, pulmonologists and other health care providers for the prevention, diagnosis, and treatment of AECOPD.
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